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1
Noma, Kensuke, Naotsugu Oyama e James K. Liao. "Physiological role of ROCKs in the cardiovascular system". American Journal of Physiology-Cell Physiology 290, n. 3 (marzo 2006): C661—C668. http://dx.doi.org/10.1152/ajpcell.00459.2005.
Testo completoAbstract (sommario):
Rho-associated kinases (ROCKs), the immediate downstream targets of RhoA, are ubiquitously expressed serine-threonine protein kinases that are involved in diverse cellular functions, including smooth muscle contraction, actin cytoskeleton organization, cell adhesion and motility, and gene expression. Recent studies have shown that ROCKs may play a pivotal role in cardiovascular diseases such as vasospastic angina, ischemic stroke, and heart failure. Indeed, inhibition of ROCKs by statins or other selective inhibitors leads to the upregulation and activation of endothelial nitric oxide synthase (eNOS) and reduction of vascular inflammation and atherosclerosis. Thus inhibition of ROCKs may contribute to some of the cholesterol-independent beneficial effects of statin therapy. Currently, two ROCK isoforms have been identified, ROCK1 and ROCK2. Because ROCK inhibitors are nonselective with respect to ROCK1 and ROCK2 and also, in some cases, may be nonspecific with respect to other ROCK-related kinases such as myristolated alanine-rich C kinase substrate (MARCKS), protein kinase A, and protein kinase C, the precise role of ROCKs in cardiovascular disease remains unknown. However, with the recent development of ROCK1- and ROCK2-knockout mice, further dissection of ROCK signaling pathways is now possible. Herein we review what is known about the physiological role of ROCKs in the cardiovascular system and speculate about how inhibition of ROCKs could provide cardiovascular benefits.
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Zhang, Jin Yu, Huan Sheng Dong, Reza K. Oqani, Tao Lin, Jung Won Kang e Dong Il Jin. "Distinct roles of ROCK1 and ROCK2 during development of porcine preimplantation embryos". REPRODUCTION 148, n. 1 (luglio 2014): 99–107. http://dx.doi.org/10.1530/rep-13-0556.
Testo completoAbstract (sommario):
Cell-to-cell contact mediated by cell adhesion is fundamental to the compaction process that ensures blastocyst quality during embryonic development. In this study, we first showed that Rho-associated coiled-coil protein kinases (ROCK1 and ROCK2) were expressed both in porcine oocytes and IVF preimplantation embryos, playing different roles in oocytes maturation and embryo development. The amount of mRNA encoding ROCK1 and the protein concentration clearly increased between the eight-cell and morula stages, but decreased significantly when blastocysts were formed. Conversely, ROCK2 was more abundant in the blastocyst compared with other embryonic stages. Moreover, immunostaining showed that ROCK1 protein distribution changed as the embryo progressed through cleavage and compaction to the morula stage. Initially, the protein was predominantly associated with the plasma membrane but later became cytoplasmic. By contrast, ROCK2 protein was localized in both the cytoplasm and the spindle rotation region during oocyte meiosis, but in the cytoplasm and nucleus as the embryo developed. In addition, ROCK2 was present in the trophectoderm cells of the blastocyst. Treatment with 15 μM Y27632, a specific inhibitor of ROCKs, completely blocked further development of early four-cell stage embryos. Moreover, we did not detect the expression ofROCK1but did detectROCK2expression in blastocysts. Moreover, lysophosphatidic acid an activator of ROCKs significantly improved the rates of blastocyst formation. These data demonstrate that ROCKs are required for embryo development to the blastocyst stage. Together, our results indicate that ROCK1 and ROCK2 may exert different biological functions during the regulation of compaction and in ensuring development of porcine preimplantation embryos to the blastocyst stage.
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Bayrak, Galyna. "MORPHOLOGIC CLASSIFICATION OF THE BESKIDS ROCKS IN THE UKRAINIAN CARPATHIANS". PROBLEMS OF GEOMORPHOLOGY AND PALEOGEOGRAPHY OF THE UKRANIAN CARPATHIANS AND ADJACENT AREAS, n. 09 (01) (25 settembre 2019): 117–32. http://dx.doi.org/10.30970/gpc.2019.1.2806.
Testo completoAbstract (sommario):
The article deals with morphological classification of the sandstone rocks in the Ukrainian Carpathians Beskids. By the methods of field measurements and mathematical computations the rock peaks heights, their shape, basement lengths and strata thickness have been calculated. The highest rock peaks in the Beskids amounts 32–37 m. The classification from the morphological point of view on the base of rock forms studying has been done. All rocks are divided in two classes: the rocks-outliers and the rocks-outcrops. Among the rocks-outliers 4 types are defined: spire-shaped, chain-shaped, arc-shaped and combined. Spire-shaped rocks are divided into subtypes: tower, spoke and needle. Among the chain-shaped rocks 3 subtypes are defined: wall, bloc and slab. The rocks of combined form are divided into subtypes: 1) with defined form – those of the rocks which are similar to certain objects and 2) undefined forms (cliffs). Among the rocks-outcrops three types are defined: cliff-shaped, canyon-shaped and angular ones. The class of rocks-outliers occurs most often. Among the types the rocks-towers occur most often. They dominate in the rock formations of Urych, Yamelnytsia and Bubnyshche. Many bloc-shaped and plate-shaped rocks are located on the Kliuch Ridge, in Bubnys’ki Rocks, Yamelnytsia. There are rocks-walls of 50–60 m in Urych and Yamelnytsia. The longest rock-wall in Danylov tract near Yamelnytsia has been investigated. Its length is 150 m and height is 17 m. Some needle and spoke rocks are situated in Bubnys’ki Rocks (Odinets’ Rock, Golets’ Rock) and Urych (Hostryi Kamin’ (Sharp Stone) Rock. Unique types are very rare. For instance: Bronenosets’ Rock in Bubnys’ki Rocks (this rock has shape of sail), Sokil (Falcon) Rock in the Kliuch Ridge, mushroom-shaped rock in Yamelnytsia. There is also unique arc-rock in the Kliuch Ridge. In the class of rocks-outcrops the types of cliff and canyon occur equally. The angular-shaped rocks are rarer. The cliff-shaped rocks are situated near Sokolova Mountain, Pozhernytsia Mountain and Kniazhi (Princes) Rocks near Tyshivnytsia. Unique rocks-canyons, the effects of tectonic breaking and gravity-erosion processes, occur on the Kliuch Ridge. The worked out morphological classification of rocks can be used by ascertaining features of rock morphogenesis with education and scientific purposes as well as by assessment of safety level and protection possibilities. Morphological types of the rocks can be considered as valuable objects of geomorphologic heritage and attractions for geo-tourism. Key words: rocks; morphology type of the rock; rock shape; Beskids of Ukrainian Carpathians.
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Haga, Raquel B., Ritu Garg, Francesca Collu, Bárbara Borda D'Agua, Sofia T. Menéndez, Audrey Colomba, Franca Fraternali e Anne J. Ridley. "RhoBTB1 interacts with ROCKs and inhibits invasion". Biochemical Journal 476, n. 17 (13 settembre 2019): 2499–514. http://dx.doi.org/10.1042/bcj20190203.
Testo completoAbstract (sommario):
Abstract RhoBTB1 is an atypical Rho GTPase with two BTB domains in addition to its Rho domain. Although most Rho GTPases regulate actin cytoskeletal dynamics, RhoBTB1 is not known to affect cell shape or motility. We report that RhoBTB1 depletion increases prostate cancer cell invasion and induces elongation in Matrigel, a phenotype similar to that induced by depletion of ROCK1 and ROCK2. We demonstrate that RhoBTB1 associates with ROCK1 and ROCK2 and its association with ROCK1 is via its Rho domain. The Rho domain binds to the coiled-coil region of ROCK1 close to its kinase domain. We identify two amino acids within the Rho domain that alter RhoBTB1 association with ROCK1. RhoBTB1 is a substrate for ROCK1, and mutation of putative phosphorylation sites reduces its association with Cullin3, a scaffold for ubiquitin ligases. We propose that RhoBTB1 suppresses cancer cell invasion through interacting with ROCKs, which in turn regulate its association with Cullin3. Via Cullin3, RhoBTB1 has the potential to affect protein degradation.
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Zarraq, Ghazi. "Slope Stability Analysis of the Southwestern Limb of Kosret Anticline in Dokan, Northeastern Iraq". Iraqi Geological Journal 54, n. 2A (31 luglio 2021): 34–48. http://dx.doi.org/10.46717/igj.54.2a.3ms-2021-07-24.
Testo completoAbstract (sommario):
The stability of the rock slopes was studied on the southwestern limb of the Kosret Anticline in the Dokan Area in northeastern Iraq to analyze and indicate the danger of rock mass failures along the public street linking Dokan and Quesangaq, Erbil and the road which link between the city and the residential neighborhood of Dokan Lake, as well as the revealing and the analysis of the risk of landslides in the slopes and rocks detectors of exposed rocks of the formations in the study area. The stereographic projection was used in the analysis and classification of the rock slopes. This study has shown that the failures of rocks are fall and day lighting bedding plane. The factors that affect the stability of the slopes were assessed. This research mainly focuses on identifying the types of collapses along the rocky slopes and the factor that affects the instability of the studied slopes. It was found that it is the direction slopes and the interruption geometry. Different treatment methods have been proposed for the studied rock base on the rock slope analysis. The expected failure types that may occur along the road are plane sliding, rock fall, toppling, and probably the failure type in the future may be planner sliding due to the angle of the friction comes to zero degree. The rocky slopes along the road require constant monitoring due to their hazardous conditions. Where it was found that the attitude of the joints and their frequency with the relation between the attitude of the slopes and the rock beds played an important role in the failures, as well as the weak rocks of the Marl layers of the Shiranish, Kometan and Tanjero formations play a key role in responding to weathering and erosion factors that increase the failures of rock slopes.
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Sirait, Happy Christin Natalia, e Veni Dewinta. "Petrology and Mineralogy of Metamorphic Rocks in The Pringsewu District, Lampung Province, Indonesia". Journal of Geoscience, Engineering, Environment, and Technology 8, n. 3 (30 agosto 2023): 203–11. http://dx.doi.org/10.25299/jgeet.2023.8.3.11347.
Testo completoAbstract (sommario):
The origin of metamorphic rock is greatly influenced by the temperature and pressure changes in every tectonic setting, especially in active subduction margins. One of the wide outcrops of metamorphic rock occurs in the Pringsewu District, Lampung, and it is a part of the Palaeozoic Gunung Kasih Complex. The presence of metamorphic rocks in Pringsewu has raised several questions and debates for some time due to the lack of research and field evidence found in this area, especially, since the origin of metamorphic rock in Lampung has been rarely studied. This research aims to determine the metamorphic rock facies and the tectonic setting underlying the formation of metamorphic rocks in the study area.
Petrographic analysis on 19 thin-section samples shows that metamorphic rock in the research area can be divided into two regions i.e., western and eastern regions. The Eastern part is characterized by muscovite-epidote schist and greenschist which consist of quartz, muscovite, actinolite, epidote, and garnet as index minerals. Whereas the western part is characterized by quartzite and biotite-epidote schist that consist of quartz, biotite, and muscovite. Based on the mineral index, metamorphic rock’s protoliths are pelitic rock, mafic rock, and quartz-feldspathic sandstone. The metamorphic rock zonation shows the created temperature is from 280-550oC.
The foliation structure such as schistose and porphyroblastic texture in the whole rocks sample indicated that metamorphic rocks are created in medium-grade metamorphism and are characterized by the greenschist facies to epidote-amphibolite facies. The abundance of quartz, k-feldspar, and labradorite minerals show that metamorphic rocks came from the microcontinent which was caused by a collision between the intra-oceanic Woyla plate and West Sumatra microcontinent in the Cretaceous. Indications of tectonic activity that create the lithology in Lampung Province need more geological study, especially to determine the absolute age of the metamorphic rock.
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Xie, Busheng, Lixin Wu, Wenfei Mao, Shengyu Zhou e Shanjun Liu. "An Open Integrated Rock Spectral Library (RockSL) for a Global Sharing and Matching Service". Minerals 12, n. 2 (20 gennaio 2022): 118. http://dx.doi.org/10.3390/min12020118.
Testo completoAbstract (sommario):
Minerals and rocks are important natural resources that are formed over a long period of geological history. Spectroscopy is the basis of the identification and characterisation of rocks and minerals via proximal sensing in the field or remote sensing systems with multi- and hyper-spectral capabilities. However, spectral data is scattered around different institutions worldwide and stored in various formats, resulting in poor data usability and an unnecessary waste of time and information. To improve the usability and performance of mineral spectral data, we developed an integrated open mineral spectral library (Rock Spectral Library, RockSL). Shared spectral data and related information were collected worldwide, and data cleaning measures were performed to retain the qualified spectra and merge all qualified data (raster, vector, and text formats) in a common framework to establish a reliable and comprehensive digital data set for an easy sharing and matching service. A software system was developed for the RockSL to manage, analyse, and apply the spectral data of minerals and rocks. We demonstrate how the information encoded in RockSL can determine the species of unknown rocks and describe specific mineral compositions. We also provide a reference scheme of the work chain and present key technologies for building different spectral libraries in diverse fields using RockSL. New contributions to RockSL are encouraged for this work to be improved to provide a better service and extend the applications of geo-sciences. This article introduces the characteristics of RockSL and demonstrates an experimental application.
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Kitchenham, Paul. "Rock Art: “Tatooing” Rocks?" Time and Mind 2, n. 3 (gennaio 2009): 347–48. http://dx.doi.org/10.2752/175169609x12464529903254.
Testo completo
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Evgenikou, V., A. Georgopoulos e M. Korres. "REASSEMBLY OF ROCK SEGMENTS, THE CASE OF AREOPAGUS HILL". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W9 (31 gennaio 2019): 325–32. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w9-325-2019.
Testo completoAbstract (sommario):
<p><strong>Abstract.</strong> There are no specifications and/or standards for the restoration of collapsed masses of rocks, as in most cases the rocks bear no historical/archaeological value and their restoration would require significant budget and resources. But plenty of colossal statues, ancient temples, tombs and whole cities are carved on the surface or even expand in the interior of solid natural rocks. These so-called rock-cut monuments are located all around the globe and, in most cases, are made on a grand scale. Earthquakes, rock’s faults, erosion and karst can lead to massive rock collapses.The purpose of this paper is to establish an integrated methodology for the relocation of detached rock segments to their original positions. Specifically, the proposed methodology is based on the case of the Areopagus Hill and involves the generation of 3d models of the rock segments, their virtual reassembly and their utilization for the reconstruction of a part of the peak of the hill.</p>
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Ren, Jia Guo, e Qian Qian Wu. "Discussion on Geological Experiment Technology in Geological Work". Advanced Materials Research 616-618 (dicembre 2012): 60–63. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.60.
Testo completoAbstract (sommario):
This essay puts silicate rocks test as example on the basic of the analysis of new technology and method of geological experiment. This essay analyses the experimental principal and process of silicate rock’s total iron content, and it based on geology experimental operation process. The essay tries to probe into silicate rock’s mineral chemical composition, rock structure and tectonics through the research of the iron content and other chemical components of silicate rocks. Furthermore, this essay also estimates the optional mineral’s component content of sandstone ore, and then evaluates mining products and industrial and economic value. It is very important to guide the development of the mine.
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Cooper, William E., e Wade C. Sherbrooke. "Choosing between a rock and a hard place: Camouflage in the round-tailed horned lizard Phrynosoma modestum". Current Zoology 58, n. 4 (1 agosto 2012): 541–48. http://dx.doi.org/10.1093/czoolo/58.4.543.
Testo completoAbstract (sommario):
Abstract The round-tailed horned lizard Phrynosoma modestum is cryptically colored and resembles a small stone when it draws legs close to its body and elevates its back. We investigated effectiveness of camouflage in P. modestum and its dependence on stones by placing a lizard in one of two microhabitats (uniform sand or sand with surface rocks approximately the same size as lizards). An observer who knew which microhabitat contained the lizard was asked to locate the lizard visually. Latency to detection was longer and probability of no detection within 60 s was higher for lizards on rock background than on bare sand. In arenas where lizards could choose to occupy rock or bare sand, much higher proportions selected rocky backgrounds throughout the day; at night all lizards slept among stones. A unique posture gives P. modestum a rounded appearance similar to many natural stones. Lizards occasionally adopted the posture, but none did so in response to a nearby experimenter. Stimuli that elicit the posture are unknown. That P. modestum is better camouflaged among rocks than on bare sand and prefers to occupy rocky areas suggests that special resemblance to rocks (masquerade) enhances camouflage attributable to coloration and immobility.
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Grzelak, Katarzyna, e Piotr Kuklinski. "Benthic assemblages associated with rocks in a brackish environment of the southern Baltic Sea". Journal of the Marine Biological Association of the United Kingdom 90, n. 1 (14 gennaio 2010): 115–24. http://dx.doi.org/10.1017/s0025315409991378.
Testo completoAbstract (sommario):
Sandy bottoms, with local patches of rocks, dominate the southern Baltic Sea coast. These rock patches create three-dimensional habitats with additional niches that can support diverse assemblages of organisms. In this study we investigated macrofaunal assemblages associated with the boulder field in the brackish Gulf of Gdansk. Of the 30 recorded taxa three animal species (Mytilus trossulus, Balanus improvisus and Electra crustulenta) together with five species of algae were directly attached to rocks. These engineering organisms provided habitats for a further 22 taxa. Among the fauna directly associated with rocks, barnacles (76%) were the most abundant while among indirectly associated biota, oligochaetes were the dominant group (45%). Rock size and algal biomass explained most variance in macrofaunal structure of the assemblages investigated. There were statistical differences in assemblage structure between two separate localities within the rocky patch, despite environmental homogeneity (salinity, water temperature and structure of sea bottom). These differences in assemblage structure were mostly due to differences in dominance of particular species rather than in species composition. Our results show that rocky patches in an otherwise soft sediment habitat provide additional living space for macrofauna leading to an increase in local biodiversity and organismal abundance.
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Cruden, D. M., e T. M. Eaton. "Reconnaissance of rockslide hazards in Kananaskis Country, Alberta". Canadian Geotechnical Journal 24, n. 3 (1 agosto 1987): 414–29. http://dx.doi.org/10.1139/t87-052.
Testo completoAbstract (sommario):
Kananaskis Country is situated in the Front Ranges of the Canadian Rockies in southwestern Alberta. Sedimentary rock thrust northeastwards forms mountain ridges that trend northwest–southeast parallel to the major thrust faults. Older, Palaeozoic rocks—mainly limestone and dolomite—form the ridges and peaks. Younger, Mesozoic rocks—sandstones, quartzites, siltstones, shales, conglomerates, and coals—are more easily eroded and form mountain passes and valleys.A reconnaissance mapped 228 rockslides, 8 km2 of rockslide debris and 96 km2 of talus. The largest rockslide exceeds 50 × 106 m3. Rockslides are most probable in the Devonian Palliser Formation, then in the Permo-Pennsylvanian Rocky Mountain Group, Mississippian Rundle Group, Devonian Fairholme Group, Mississippian Banff Formation, and the younger detrital rocks. Rockslides are most probable on dip and overdip slopes, followed by reverse-dip slopes, oblique and strike-dip slopes, and underdip slopes. Large rock masses have not slid on slopes below their basic friction angle, [Formula: see text]The reconnaissance shows that certain facilities in valleys below steep mountain slopes are exposed to rockslide hazards, and provides a guide for the location of new facilities. Analyses of two mountain slopes show that there are large, hypothetical hazards in Kananaskis. Rockslides are likely and could be destructive. Key words: Front Ranges, Rocky Mountains, Alberta, rockslides, hazards.
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Pujar, Anant G., A. Sreenivasa e Ajaykumar N. Asode. "Petrography and Provenance Study of South-Central Part of Kaladgi Basin, Belgaum, Karnataka, India". International Journal of Economic and Environmental Geology 11, n. 1 (7 luglio 2020): 108–12. http://dx.doi.org/10.46660/ijeeg.vol11.iss1.2020.421.
Testo completoAbstract (sommario):
The area under investigation covers the south-central part of Kaladgi series comprising of sedimentary rocks, mainly quartzarenites. From the geological point of view the study area comprises southcentral part of Kaladgi basin covering around 54 km2 which encompasses rocky hills of moderate height, showing three types of facies i.e., argillaceous, arenaceous and rudaceous. Among these three, arenaceous facies is more prominent in the area. These sedimentary rocks rest unconformably over gneisses. Detailed study of the rocks exposed are done by studying the petrological aspects of the rock samples which were subjected to microscopic studies, bifurcating different minerals and counting each parameter of the minerals which is plotted in the QFR ternary diagram and further illustrating the tectonic provenance of the area. Present work mainly focuses on the studies related to petrological, diagenesis and provenance of the study area where the rocks exposed in the vicinity are quartz arenites indicating that these sediments were deposited in a riverine condition.
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Pujar, Anant G., A. Sreenivasa e Ajaykumar N. Asode. "Petrography and Provenance Study of South-Central Part of Kaladgi Basin, Belgaum, Karnataka, India". International Journal of Economic and Environmental Geology 11, n. 1 (7 luglio 2020): 108–12. http://dx.doi.org/10.46660/ojs.v11i1.421.
Testo completoAbstract (sommario):
The area under investigation covers the south-central part of Kaladgi series comprising of sedimentary rocks, mainly quartzarenites. From the geological point of view the study area comprises southcentral part of Kaladgi basin covering around 54 km2 which encompasses rocky hills of moderate height, showing three types of facies i.e., argillaceous, arenaceous and rudaceous. Among these three, arenaceous facies is more prominent in the area. These sedimentary rocks rest unconformably over gneisses. Detailed study of the rocks exposed are done by studying the petrological aspects of the rock samples which were subjected to microscopic studies, bifurcating different minerals and counting each parameter of the minerals which is plotted in the QFR ternary diagram and further illustrating the tectonic provenance of the area. Present work mainly focuses on the studies related to petrological, diagenesis and provenance of the study area where the rocks exposed in the vicinity are quartz arenites indicating that these sediments were deposited in a riverine condition.
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Dimitrov, Ivan. "Structural geological methods in the geotechnical practice – rock mass rating. Advantages and problems of the rating methods". Review of the Bulgarian Geological Society 81, n. 1 (2020): 35–54. http://dx.doi.org/10.52215/rev.bgs.2020.81.1.3.
Testo completoAbstract (sommario):
This paper presents a review of the most common geotechnical rock rating methods. The directional properties of the rock’s anisotropies are exemplified, by a case of resolution of stresses in folded and foliated metamorphic rocks. In such rocks, depending on the geometry of the folds, the ambient stress field can generate varying shear potential along the foliation planes in different parts of the excavation. The commonly used rating schemes, with accent on the geological feasibility of the classifications, are discussed – Protodiakonov’s rock scale, Terzaghi’s grading for construction of tunnels, then the rock quality designation of Deere, the Bieniawski’s rock mass rating (RMR), the Hoek, and Brown’s GSI and the Barton’s Q-system. It is emphasized that in spite of its broad use, the RQD is distorting the statistical weight of the joint groups as some steeply dipping joints may be completely neglected. It is recognized that the RMR is the simplest to use but underestimates the directional properties of the rock anisotropies, which require better definition and has no provision for lithologically varying rock packages, although it has the advantage of using the uniaxial compressive strength, which other systems do not employ. The Hoek and Brown’s criterion went too far with complex empirical relationships, which rely on extensive laboratory testing, so it is no more field criterion. Besides, its geological descriptive powers are rather poor and now, new form of GSI classification is offered for nearly every lithological type. Barton’s Q-system, being best suited to case studies of actual underground constructions, suffers from the fact that is centered nearly exclusively on joints, which may be justified in Norway, where mainly magmatic and high grade metamorphic rocks are present but should be applied cautiously in areas, where sedimentary, volcanic and strongly foliated rocks are exposed. In general, for all the discussed geomechanical classification systems (RMR, GSI, Q) the rule is valid, that they work better in an isotropic, strong but jointed rock masses and do not work well in week layered and foliated rocks.
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Priya, Rashmi, Xuan Liang, Jessica L. Teo, Kinga Duszyc, Alpha S. Yap e Guillermo A. Gomez. "ROCK1 but not ROCK2 contributes to RhoA signaling and NMIIA-mediated contractility at the epithelial zonula adherens". Molecular Biology of the Cell 28, n. 1 (gennaio 2017): 12–20. http://dx.doi.org/10.1091/mbc.e16-04-0262.
Testo completoAbstract (sommario):
Rho kinases (ROCK1 and ROCK2) function downstream of the small GTPase RhoA to drive actomyosin cytoskeletal remodeling. It has often been believed that ROCK1 and ROCK2 may be functionally redundant, as they share a highly conserved kinase domain. However, in this study, we report differential functional effects for these ROCKs at the epithelial zonula adherens (ZA). Using specific siRNA, we found that ROCK1 depletion disrupted cadherin organization at the ZA, accompanied by loss of F-actin and NMIIA, whereas ROCK2 knockdown had no significant effect. Further, ROCK1, but not ROCK2, was necessary to stabilize GTP-RhoA at the ZA, thereby sustaining junctional tension and inhibiting intraepithelial cell movement. We also found that nonmuscle myosin IIA is a major determinant of ROCK1 cortical stability. Thus, despite sharing the catalytic domain with ROCK2, ROCK1 appears to be the dominant kinase essential for junctional integrity and contractile tension at epithelial ZA.
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Dias, Gilmar Pauli, e Emílio Velloso Barroso. "Determinação experimental do coeficiente de restituição normal de rochas: aplicação na previsão do alcance de blocos em encostas". Anuário do Instituto de Geociências 29, n. 2 (1 gennaio 2006): 149–67. http://dx.doi.org/10.11137/2006_2_149-167.
Testo completoAbstract (sommario):
Among the several parameters involved in rock fall analisys, the restitution coefficient, which is related to the kinetic energy wasted after repeated impacts of a rocky body against the ground, is probably the most important and most difficult to acquire. There is the necessity of in situ tests where blocks of rocks are thrown down on the slopes. However these tests cannot be performed in places where people or urban equipments could be in risk. In this paper an acoustic method is used for the measurement of the normal restitution coefficient of rocks. This method is very well known by physicists but it has not been applied in the geosciences and engineering areas. It consists in the sound recording of successive impacts of a rock sphere against a smooth rocky surface. The gravity acceleration was back calculated from data obtained in order to verify if precision of the method is suitable. A sensibility analysis of the coefficient of restitution was already carried out simulating real rock fall problems.
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Wang, Yafei, Zhanrong Zhang, Xingpei Kang, Hao Xie, Chenchen Wang e Kun Liu. "Stability Analysis of Soil and Rock Mixed Slope Based on Random Heterogeneous Structure". Advances in Civil Engineering 2024 (19 febbraio 2024): 1–12. http://dx.doi.org/10.1155/2024/1448371.
Testo completoAbstract (sommario):
Due to the complexity in the heterogeneous internal structure and interactions between rocks and soil, the slide of soil–rock mixed slope is usually more complex than that of a homogeneous soil slope. This paper investigated the stability of soil–rock mixed slopes with finite element method (FEM) based on random heterogeneous structure. An image-aided approach was used to generate the 2-D and 3-D digital rocks to ensure the morphology of digital rocks was similar with the real rocks. The 2-D and 3-D soil–rock mixed slopes were then generated by placing the digital rocks into the soil matrix. The generated heterogeneous structures of soil–rock mixed slope were imported into ABAQUS for numerical analysis. The effect of rock content, spatial distributions, material properties, and rock–soil interface on the stability of soil–rock mixed slopes were analyzed. Results show that the stability factor of the soil–rock mixed slope increases with the increase of rock content. The rocks can play a certain degree of antislide effect in the slope. The uneven spatial distribution of rocks has effect on the overall stability of soil–rock mixed slope. This effect is more significant when the rock content is moderate. Rocks distributed in the middle layer of the slope may improve the overall antisliding performance of the slope. The stability factor decreases with the increase of rock density. While the effect of rock elastic modulus on stability of soil–rock mixed slope is relatively limited. The contact condition at the soil–rock interface has effect on the overall stability of soil–rock mixed slope. It is recommended to properly determine the interface properties for stability analysis of soil–rock mixed slope.
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Tang, Fujian, Yizheng Chen, Zhaochao Li, Xiuyan Hu, Genda Chen e Yan Tang. "Characterization and field validation of smart rocks for bridge scour monitoring". Structural Health Monitoring 18, n. 5-6 (22 gennaio 2019): 1669–85. http://dx.doi.org/10.1177/1475921718824944.
Testo completoAbstract (sommario):
In this study, two types of smart rocks are proposed, characterized, and validated for bridge scour monitoring, including the arbitrary oriented system smart rock and the automatically pointing to south system smart rock. Effect of the smart rocks on the geomagnetic field is numerically studied, and algorithms to localize the position of the smart rocks are developed. Field validation tests are conducted at an open area in Rolla, MO, USA. Results show that the magnetic intensity decreases in cubic function with a distance away from the smart rock. The algorithm can effectively localize the position of smart rocks during validation tests. The effective monitoring range of the two smart rocks is dependent on the flux (or size) of the magnet used to fabricate the smart rocks, the accuracy of the magnetometer, the direction of smart rocks, as well as the intensity and variation of the ambient magnetic field. Compared with arbitrary oriented system smart rock, less measurement points are needed to localize the automatically pointing to south system smart rock.
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Lee, Dong-Keun, Duk-Ho Chung, Woong-Hyeon Jeon e Chul-Min Lee. "Analysis of igneous rock classification process by earth science teachers using eye trackers". Korean Association For Learner-Centered Curriculum And Instruction 22, n. 15 (15 agosto 2022): 461–77. http://dx.doi.org/10.22251/jlcci.2022.22.15.461.
Testo completoAbstract (sommario):
Objectives The purpose of this study is to find out the characteristics that earth science teachers show in the process of classifying igneous rocks and the difficulties in classifying igneous rocks.
Methods To this end, the researchers collected gaze data and language data in the process of classifying igneous rocks by using a Eyetracker(Tobii Ⅱ) and a think-aloud method from five high school earth science teachers in Jeollabuk-do. Then, the collected data were analyzed using the gaze analysis program and the semantic network analysis, respectively.
Results First, in the process of classifying igneous rocks, earth science teacher’s gaze fixation duration was long in the order of diorite, andesite, rhyolite, gabbro, basalt, and granite. Second, in the semantic network for the classification of igneous rocks by earth science teachers, the eigenvector centrality of words related to the apparent characteristics of rocks such as “particles” and “rock color” was high. Third, in the process of classifying igneous rocks, earth science teachers found it difficult to determine the range of characteristics that determine each igneous rock, that is, the range of rock colors, particle sizes, stripes, etc. In other words, earth science teachers found it most difficult to distinguish diorite, and granite was the easiest to distinguish. In the process of classifying igneous rocks, they classified igneous rocks mainly based on the size of the particles that make up the rocks and the color shown by the rocks rather than the minerals that make up the rocks. In addition, earth science teachers were unclear about the scope of the criteria for classification of igneous rocks.
Conclusions Earth science teachers need to clearly establish personal standards for the classification of igneous rocks. And personal standard for rock classification can be established through various observation experiences as well as the geological knowledge they perceive. Therefore, earth science teachers should be provided with various types of rocks and typical rocks for extensive observation experiences, such as activities to observe rocks and various types of rocks.
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Ahmed, Tufail, Syed Hafeez Ur Rehman, Fahim Ahmed Ibupoto, Asif Abbas, Sami Ullah, Abbas Hussain e Shehzad Usman. "EXPERIMENTAL INVESTIGATION OF DURABILITY AND STRENGTH OF SANDSTONE AND SHALE OF UNITED MINERAL COAL COMPANY SOR-RANGE, BALOCHISTAN". Journal of Mountain Area Research 7 (19 maggio 2022): 56. http://dx.doi.org/10.53874/jmar.v7i0.143.
Testo completoAbstract (sommario):
Mining operations deal mainly with hard and soft rocks with different mechanical properties and varying strengths. The aim of the slake durability test is to present an index related to degradation resistance of rock when exposed to standard cycles of wetting and drying. Research in geology and rock mechanics is done to explain the influence of the rock index properties in determining the strength, durability and pulse velocity of the rock. This paper enlightens the prediction of the rock’s behavior and nature of the degradation of rocks The index values obtained for sandstone are varying from 97.36 to 99.04% and for shale it ranges from 10.21 to 14.06%. The slake durability index test for sandstone sample indicates that it is high durable and the shale indicates very low durability. The average value of uniaxial compressive strength was calculated to be 83.144 MPa.
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Shen, Shijie, Yanfang Gao e Lichun Jia. "A Comparison of the Relationship between Dynamic and Static Rock Mechanical Parameters". Applied Sciences 14, n. 11 (24 maggio 2024): 4487. http://dx.doi.org/10.3390/app14114487.
Testo completoAbstract (sommario):
The rock’s mechanical properties play an important role in the whole process of conventional and unconventional oil and gas exploration and progression. At present, there are two approaches to determining the mechanical parameters. One is to measure the rock sample in the laboratory (i.e., static elastic modulus Es). The other is to obtain parameters by geophysical logging data (i.e., dynamic elastic modulus Ed). In general, static parameters can more accurately reflect the mechanical properties of rock under actual geo-stresses. At the same time, their determinations are difficult. Therefore, one of the best methods is to establish the correlation between the dynamic and static parameters. This paper investigates the relation between the dynamic and static parameters using different methods for various rocks in the literature. Based on the relationship of Es=aEd+b, a correction between a and b is proposed using the multinomial form a=0.67+0.101b−0.006b2+0.0001b3. It is found that the Es can be derived from the Ed just when the parameter b is known. In terms of different types of rocks, for igneous and metamorphic rocks, the best correlation between Es and Ed obeys the power-law correlation; for sedimentary rocks, there are linear and logarithmic correlations. Theoretically, the difference between dynamic and static elastic moduli can be attributed to microcracks and pores within rocks. This study can provide guidance for engineers to predict the desired static parameters precisely using logging or seismic data.
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Shine, Richard, Jonathan K. Webb, Mark Fitzgerald e Joanna Sumner. "The impact of bush-rock removal on an endangered snake species, Hoplocephalus bungaroides (Serpentes : Elapidae)". Wildlife Research 25, n. 3 (1998): 285. http://dx.doi.org/10.1071/wr97022.
Testo completoAbstract (sommario):
We examined the impact of habitat degradation (removal of surface rocks) on an endangered snake species (Hoplocephalus bungaroides, Elapidae) at 23 sites in south-eastern Australia, by quantifying the impact of rock removal on (i) the availability of suitable shelter-sites for the snakes and their major prey species (the velvet gecko, Oedura lesueurii), and (ii) the numbers of snakes and geckos. Our survey showed that both the snakes and the geckos prefer rocks lying on other rocks, rather than on soil, and select rocks of particular sizes. The rocks removed by bush-rock collectors overlap considerably in size (diameter and thickness) and substrate (rock on rock) with those used by broad-headed snakes and velvet geckos. Multivariate path analysis suggests that population densities of broad-headed snakes (as measured by capture rates) may be determined primarily by gecko numbers, which in turn depend upon availability of suitable rocks. In some sites, rock numbers were substantially reduced by anthropogenic disturbance. Thus, our survey data suggest that bush-rock removal has contributed to the endangerment of H. bungaroides.
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Al-Azazi, Nabeel A. S., A. S. A. E. Alsrory e Mohammed Albaroot. "Upper Jurassic Source Rock Evaluation and Thermal Maturity Evolution of the NW Sab’Atayn Basin, Yemen". Geoinformatica Polonica 22 (1 dicembre 2023): 69–82. http://dx.doi.org/10.4467/21995923gp.23.006.18605.
Testo completoAbstract (sommario):
Of Yemen’s Mesozoic basins, the Sab’atayn Basin offers the most significant potential for oil and gas exploration. The key consideration in the evaluation of source rocks to hydrocarbon exploration is the quantity and nature of the organic materials in sedimentations. Using organic geochemistry and total organic carbon content, organic-rich sediments from the Meem (Lower) and Lam (Upper) members from four wells in the NW Sab’atayn Basin were evaluated. The information gained reveals that the Meem source rocks have a total organic carbon content (TOC) value between 0.2–1.68 wt%, therefore suggests fair to very good source rocks. Only two samples in the Kamaran-01 well had values greater than 3 wt%, compared to the Lam source rocks’ values, which range from 0.2 to 3.81 wt%, which suggest excellent source rocks. The majority of the samples are made up of reworked organic debris, with no possibility for interesting source rocks, according to the Rock-Eval pyrolysis data. The majority of the Meem and Lam source rocks samples under study have Tmax values below 440 °C, placing them in the immature to marginally mature and on the main periphery of main phases of hydrocarbon formation. Based on the results of the Meem source rocks’ generative potential (GP), it may be inferred that non-generative rocks status of Meem source rocks due to GP values less than 2 mg HC/gm rock. Additionally, if the burial depth is sufficient to generate the necessary temperature and pressure, source rocks with extraordinarily high GP values of more than 10 mg Hc/g rock may serve as an efficient source rock for the Dahamr Ali-01 well. On the other hand Lam source rock is classified as moderate source rocks. Non-generative potential has been reported from Lam source rock in Himyar-01 well where the GP is less than 1 mg HC/g rock. The cross-plots of pyrolysis characteristics, such as HI versus Tmax (modified van Krevelen diagram) and TOC vs S2, which are most likely the result of deposition of more terrigenous type III organic materials derived from terrestrial in the study area, can be used to determine the kerogen type for Lam and Meem source units. The analysis of Meem source rocks demonstrated that they are typically plotted in the mature zone; however samples of Lam source rocks proved that they have been still immature, merely marginally mature in the Dahamr Ali-01 and Saba-01 wells.
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Korol, Anton. "The influence of the rigidity of mining security structures on the stability of side rocks in the coal-rock massif". Technology audit and production reserves 3, n. 1(59) (30 giugno 2021): 19–22. http://dx.doi.org/10.15587/2706-5448.2021.235403.
Testo completoAbstract (sommario):
The object of research is the processes of controlling the state of side rocks to prevent the collapse of the stratified rock strata in the coal-rock massif containing the workings. The studies carried out made it possible to establish the influence of the rigidity of the guard structures of mine workings on the stability of side rocks in the coal-rock massif. It is proved that as a result of the action of an external compressive load on the supporting lateral rocks, the structure, in the form of a model of bunches made of wooden posts, increases its rigidity until the destruction of the security structure. After that, there is an increase in the convergence of side rocks and their destruction. The change in the stiffness of the crushed rock in the filling massif model, which is used to support the lateral rocks, occurs as a result of the compaction of the original material. This is due to repackaging of crushed rock fractions of different sizes and its additional grinding. As a result of this interaction of the side rocks with the filling massif, the integrity of the roof and soil is ensured and convergence is limited. To assess the stability of side rocks, it is proposed to use a dimensionless stress concentration factor k. This coefficient takes into account the rigidity of the guard structures of the mine workings and the flexural rigidity of the side rocks. It was found that when the values of the coefficient k are close to zero (k→0), there is a loss of stability of the guard structures of mine workings and the destruction of side rocks in the coal-rock massif. The preservation of the integrity of the side rocks and the stability of security structures is ensured at values of k>0.1, which corresponds to the parameters of the pliable supporting structures. Most favorably on the condition of side rocks in the coal-rock massif is influenced by the method of backing up the mined-out space of crushed rock. The use of this method excludes the collapse of side rocks. When solving the problem of stability of mine workings at the stage of making technical decisions, it is necessary to predetermine the issues of rigidity of security structures with deformation characteristics of side rocks.
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Iamrurksiri, Anusorn, Takashi Tsubouchi e Shigeru Sarata. "Rock Moving Operation Using a Rod-Shaped Manipulator". Journal of Robotics and Mechatronics 25, n. 1 (20 febbraio 2013): 232–39. http://dx.doi.org/10.20965/jrm.2013.p0232.
Testo completoAbstract (sommario):
At the working front in a quarry, a hydraulic breaker is used to break large rocks into suitable sizes before they are fed into a rock crusher machine. The purpose of this study is to automate the rock breaking operation using a hydraulic breaker. In rock breaking operations, because the range of motion of hydraulic breakers suitable for breaking rocks is limited, the operator of a hydraulic breaker has to use a chisel, which is located at the top of the hydraulic hammer, to bring large rocks closer before they are broken. In this paper, we describe an approach, using stereo vision, to recognize the positions and shapes of large rocks and the automation of rock moving operations. For rock recognition and rock moving experiments, we set up a scaled down experimental environment in a laboratory and use small rocks and a robotic manipulator in the experiments.
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Zhang, Ying Hua, Bo Chuan Zhao, Zhou Jing Ye, Zhi An Huang e Ming Shan Gong. "Experiment Research of Luming Molybdenum Mine Rock Physical and Mechanical Properties". Advanced Materials Research 881-883 (gennaio 2014): 1726–31. http://dx.doi.org/10.4028/www.scientific.net/amr.881-883.1726.
Testo completoAbstract (sommario):
Physical and mechanical properties of rocks are the fundamental factors affecting the slope stability, the rock physical and mechanical properties of the Luming molybdenum mine were tested and analyzed in the laboratory. The results can provide us the basic data and reference to do numerical simulation and physical simulation of slope stability. The experimental results showed that: the greater the depth of rock of Luming molybdenum mine, the greater the density becomes,so as the freeze-thaw coefficient; the rock strength complies with the general rule; uniaxial tensile strength of dried rocks is much larger than water-saturated rocks; various rocks compressive strength σ3 rose up with σ1 rising; the shear strength of the rocks containing weak structure surface is far less than the shear strength of the intact rocks.
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Bakri, Hasbi, Imran Imran, Ulva Irvan e Adi Maulana. "Petrology and Geochemistry of Intrusive Rocks in the Tanjung Area, South Sulawesi, Indonesia: Implications for Magma Origin, Source Materials, and Geodynamic Setting". Iraqi Geological Journal 57, n. 1C (31 marzo 2024): 165–86. http://dx.doi.org/10.46717/igj.57.1c.12ms-2024-3-24.
Testo completoAbstract (sommario):
The origin of magma, source materials, and geodynamic setting of plutonic and volcanic rocks was elucidated by studying the characteristics of the rocks in the Tanjung area, South Sulawesi, Indonesia. The composition of plutonic rocks is dominated by granodiorite, granite, monzonite, and quartz monzonite, whereas volcanic rocks consist of porphyry basalt, amygdaloidal basalt, trachyte, and trachy-andesite. The main minerals in the rocks are quartz, K-feldspar plagioclase feldspars, Hornblende, biotite, pyroxene, and some opaque minerals. Plots of plutonic rock samples with calc-alkaline affinity indicated a typical I-type granitic rock. Meanwhile, plots of volcanic rock samples with calc-alkaline to shoshonitic affinity indicated S- and I-type basaltic rocks. Harker diagrams suggested that the rocks underwent crystallisation fractionation during magma evolution. Plutonic and Volcanic rocks showed enrichment of LILE and LREE and negative Eu anomalies, which resemble continental crust affinity. It is a product of partial melting in the upper continental crust. The geochemical characteristics demonstrate the relationship between the subduction environment and a continental arc.
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Liu, Weiji, Feilong Yang e Xiaohua Zhu. "Investigating the Impact of Pores on Rock Damage during Thermal Spalling Drilling". International Journal of Petroleum Technology 10 (27 ottobre 2023): 96–114. http://dx.doi.org/10.15377/2409-787x.2023.10.8.
Testo completoAbstract (sommario):
Numerous microcracks and pores in geological rock formations cause early flaws. High temperatures increase these fractures and pores, thermally damaging reservoir rocks and changing the rock failure mechanism. However, research on pores' high-temperature thermal spalling and fragmentation effects on heterogeneous rocks is sparse. This study built a finite element numerical model of heterogeneous granite rock thermal damage with pores based on rock thermal fracture theory and the Voronoi method and explored the mechanism under varied pore settings. The research's findings indicate that the application of high temperatures to local heterogeneous porous rocks results in a higher proportion of tensile damage. The proportion of shear damage and tensile damage constantly varies due to the changing position and shape of the pores. The rock's porosity has the effect of decreasing temperature in the direction of heat transfer while increasing the extent of temperature transfer along the pore parallel to the heating surface. The potential degree of damage increases as the density of pores increases, the distances between them decrease, and the pore lengths increase. The thermal damage resulting from heating in the vicinity of the pore is primarily localized in the area between the pore and the heated surface. This effect becomes more significant as the distance between them decreases. The findings of this study can serve as a theoretical framework for understanding the impact of rock pores on rock thermal fracturing and fragmentation in the thermal spalling-assisted development of deep oil and gas resources.
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Love, Sean D., e Robert C. Bailey. "Community development of epilithic invertebrates in streams: independent and interactive effects of substratum properties". Canadian Journal of Zoology 70, n. 10 (1 ottobre 1992): 1976–83. http://dx.doi.org/10.1139/z92-268.
Testo completoAbstract (sommario):
The composition of macroinvertebrate communities living on rocks in streams depends on arrivals at a particular rock, available microhabitats, and biotic interactions among colonizers. We manipulated the color (dark, light), size (82 – 1320 cm2 surface area), and shape (sphere, rectangle, cube) of individual rocks to assess their independent and interactive effects on the development of the epilithic community and the physical displacement (i.e., disturbance) of the particles. Disturbance depended on the size and shape of the rocks. Smaller particles were more disturbed, while rectangular rocks of a given size had more frequent disturbance events than spheres or cubes. Many interactions among the manipulated factors were detected in their effects on taxonomic richness and total invertebrate abundance and density. Although several commonly observed effects were found (e.g., increased richness with greater substratum complexity and size), these patterns depended in many cases on the particular set of shapes and colors examined. Additionally, the site (5 m2) within the experimental area where a rock was located had strong effects on both disturbance and the invertebrate community. The two most common taxa also differed in their relationship with disturbance on different particle shapes: Chironomidae were relatively common on more frequently disturbed rectangular and cubic shapes, while Simulium were more common on the less disturbed spheres. Generalizations about the effects of substratum characteristics (e.g., size, "complexity") should be made with caution. Different features of the rock itself, qualities of the rock's location at a larger spatial scale, seasonal influences, and variation in response among taxa may all influence the development of the epilithic community in an interactive fashion.
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He, M. M., F. Pang, H. T. Wang, J. W. Zhu e Y. S. Chen. "Energy Dissipation-Based Method for Strength Determination of Rock under Uniaxial Compression". Shock and Vibration 2020 (13 agosto 2020): 1–13. http://dx.doi.org/10.1155/2020/8865958.
Testo completoAbstract (sommario):
The energy conversion in rocks has an important significance for evaluation of the stability and safety of rock engineering. In this paper, some uniaxial compression tests for fifteen different rocks were performed. The evolution characteristics of the total energy, elastic energy, and dissipated energy for the fifteen rocks were studied. The dissipation energy coefficient was introduced to study the evolution characteristics of rock. The evolution of the dissipation energy coefficient for different rocks was investigated. The linear interrelations of the dissipation energy coefficients and the yield strength and peak strength were explored. The method was proposed to determine the strength of rock using the dissipation energy coefficients. The results show that the evolution of the dissipation energy coefficient exhibits significant deformation properties of rock. The dissipation energy coefficients linearly increase with the compaction strength, but decrease with the yield strength and peak strength. Moreover, the dissipation energy coefficient can be used to determine the rock burst proneness and crack propagation in rocks.
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Prémaillon, Mélody, Vincent Regard, Thomas J. B. Dewez e Yves Auda. "GlobR2C2 (Global Recession Rates of Coastal Cliffs): a global relational database to investigate coastal rocky cliff erosion rate variations". Earth Surface Dynamics 6, n. 3 (9 agosto 2018): 651–68. http://dx.doi.org/10.5194/esurf-6-651-2018.
Testo completoAbstract (sommario):
Abstract. Rocky coast erosion (i.e., cliff retreat) is caused by a complex interaction of various forcings that can be marine, subaerial or due to rock mass properties. From Sunamura's seminal work in 1992, it is known that cliff retreat rates are highly variable over at least four orders of magnitude, from 1 to 10 mm yr−1. While numerous local studies exist and explain erosion processes at specific sites, there is a lack of knowledge at the global scale. In order to quantify and rank the various parameters influencing erosion rates, we compiled existing local studies into a global database called GlobR2C2 (which stands for Global Recession Rates of Coastal Cliffs). This database reports erosion rates from publications, cliff setting and measurement specifications; it is compiled from peer-reviewed articles and national databases. In order to be homogeneous, marine and climatic forcings were recorded from global models and reanalyses. Currently, GlobR2C2 contains 58 publications that represent 1530 studied cliffs and more than 1680 estimated erosion rate. A statistical analysis was conducted on this database to explore the links between erosion rates and forcings at a global scale. Rock resistance, inferred using the criterion of Hoek and Brown (1997), is the strongest signal explaining variation in erosion rate. Median erosion rates are 2.9 cm yr−1 for hard rocks, 10 cm yr−1 for medium rocks and 23 cm yr−1 for weak rocks. Concerning climate, only the number of frost days (number of day per year below 0 ∘C) for weak rocks shows a significant, positive, trend with erosion rate. The other climatic and marine forcings do not show any clear or significant relationship with cliff retreat rate. In this first version, GlobR2C2, with its current encompassing vision, has broad implications. Critical knowledge gaps have come to light and prompt a new coastal rocky shore research agenda. Further study of these questions is paramount if we one day hope to answer questions such as what the coastal rocky shore response to sea-level rise or increased storminess may be.
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Fu, Mengxiong, Shuaishuai Huang, Shaowei Liu e Housheng Jia. "Experimental Study on the Size of Rock Fragments Ejected from Boreholes Drilled in Coal Mine Roadway Floors". Minerals 13, n. 3 (10 marzo 2023): 392. http://dx.doi.org/10.3390/min13030392.
Testo completoAbstract (sommario):
Borehole drilling is required if floor heave in underground mines is to be controlled using bolts through the floor. How well the bolt is anchored depends, in part, on the borehole’s quality. A major factor that can reduce borehole quality is the difficulty of discharging rock fragments from a small-diameter borehole drilled at a downward angle. Therefore, a fuller understanding of the sizes of the rock fragments will aid attempts to achieve smooth fragment discharge. In this study, drilling experiments in the laboratory and SEM imaging were carried out to determine the size and shape of the fragments generated when drilling boreholes in three sedimentary rocks typically found in roadway floors. The results show that the size distribution of the rock fragments conformed to the three-parameter generalized extreme value distribution. The mean fragment size increased with rock density and the mean size of the fragments larger than 1.5 mm increased with the rock’s uniaxial compressive strength. The fractal dimension of the cracks in the fragments was lower for high-density rocks and the mean fragment size was larger for rocks whose cracks had a lower fractal dimension. When a drill rod drills through very dense or high-strength rock, the mean size of the fragments will increase and the discharge power should be increased to prevent fragment discharge blockages. This paper may provide a theoretical basis and a data reference for discharge power settings and discharge channel optimization.
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Al-Rubiaa, S. H., e M. F. Al-Shahwan. "Rock typing and Prediction Permeability Using Machine Learning Techniques in Mishrif formation, southern Iraq". IOP Conference Series: Earth and Environmental Science 1300, n. 1 (1 febbraio 2024): 012040. http://dx.doi.org/10.1088/1755-1315/1300/1/012040.
Testo completoAbstract (sommario):
Abstract Mishrif Formation is one of the major carbonate reserves. Classifying rock types and Predicted Permeability in the Mishrif Formation in four wells (A, B, C, and D) is the primary goal of this research. Using Machine Learning Techniques, this research applies rock-typing techniques like the Flow Zone Indicator (FZI) method. In a core plug dataset, we can use unsupervised learning methods to automatically cluster hydraulic flow units (HFU) based on flow zone indicators (FZI), and we can use a supervised learning method by combining core and well log data to predict HFU (rock type) for the interval depths of the wells without core data. In this method, we were able to classify rocks into five distinct groups, or “rock types,” or “RT” for short. RT1 rocks are the highest quality reservoir rocks, RT2 rocks are of good quality, RT3 rocks are of intermediate quality, RT4 rocks are of poor quality, and RT5 rocks are of very poor quality. Accurately estimating permeability in each rock type, not only does this help reduce uncertainty that occurs in reservoirs, but it also drives improvements in project economics by optimizing resource allocation and lowering costs. This is all thanks to the use of machine learning algorithms, which have proven to be highly effective in significantly enhancing the accuracy and precision of permeability predictions.
36
Xia, Bin Wei, Ke Hu, Yi Yu Lu, Dan Li e Zu Yong Zhou. "Model Test Study on Influences of Layered Rock Mass Dip Angle on Stability of Deep-Buried Tunnel". Applied Mechanics and Materials 90-93 (settembre 2011): 2363–71. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2363.
Testo completoAbstract (sommario):
Physical models of layered rock mass with different dip angles are built by physical model test in accordance with the bias failure characteristics of surrounding rocks of layered rock mass in Gonghe Tunnel. Bias failure characteristics of surrounding rocks in thin-layered rock mass and influences of layered rock mass dip angle on stability of tunnel are studied. The research results show that failure characteristics of physical models generally coincide with those of surrounding rocks monitored from the tunnel site. The failure regions of surrounding rock perpendicular to the stratification planes are obviously larger than those parallel to. The stress distributions and failure characteristics in the surrounding rocks are similar to each physical model of different dip angles. The stress distributions and failure regions are all elliptic in shape, in which the major axis is in the direction perpendicular to the stratification planes while the minor axis is parallel to them. As a result, obvious bias failure of surrounding rocks has gradually formed. The physical model tests provide reliable basis for theoretical analysis on the failure mechanism of deep-buried layered rock mass.
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Fernández, F. J., e S. Llana-Fúnez. "Deformación asociada a la falla de Valdoviño (Noroeste del Macizo Ibérico) Deformation related to the Valdoviño fault (Northwest Iberian Massif)". Trabajos de Geología 36, n. 36 (12 settembre 2018): 95. http://dx.doi.org/10.17811/tdg.36.2016.95-118.
Testo completoAbstract (sommario):
Resumen: La sección costera de la falla de Valdoviño expone rocas de falla deformadas en las proximidades de la base de la zona sismogénica de la corteza Ibérica Varisca, en la que estructuras frágiles discretas afectan una zona de deformación predominantemente dúctil. El núcleo de la falla contiene rocas ultramáficas, rocas máficas con granate, anfibolitas, neises cuarzo-feldespáticos y metavulcanitas básicas entre las facies deformadas del granitoide Varisco de A Espenuca. Este artículo describe la deformación y microestructuras relacionadas con la falla desarrolladas en el granitoides. La composición y características tectonometamórficas del resto de rocas presentes en el núcleo de la falla sugieren que las estructuras asociadas a la falla se superpusieron a fábricas tectónicas previas, similares a las que presentan las rocas de los complejos alóctonos del NO del Macizo Ibérico.Palabras clave: microestructura, rocas de falla, corteza continental, EBSD, Orógeno Varisco.Abstract: The coastal section across the Valdoviño fault exposes fault-related rocks deformed at the base of the seismogenic zone of the Iberian Variscan crust. Discrete brittle structures are superimposed over previous predominant ductile deformation fabrics in most rocks. The core of the fault contains ultramafic rocks, garnet-bearing mafic rocks, amphibolites, quartzo-feldspathic gneisses and basic metavulcanites, in between the deformed facies of the A Espenuca Variscan granitoid. We show the deformation and microstructures related to the fault developed in the Variscan granitoid. The composition and tectonometamorphic features of the rest of the related rocks at the core of the fault suggest that deformation structures are superposed onto earlier tectonic fabrics, similar to those present in the rocks of the allochthonous complexes of the NW Iberian Massif.Keywords: microstructure, fault-related rocks, continental crust, SEM-EBSD, Variscan Orogeny.
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Cai, Yuhe, Yankun Ma, Teng Teng, Yi Xue, Linchao Wang, Zhengzheng Cao e Zhizhen Zhang. "Risk Assessment and Analysis of Rock Burst under High-Temperature Liquid Nitrogen Cooling". Water 16, n. 4 (6 febbraio 2024): 516. http://dx.doi.org/10.3390/w16040516.
Testo completoAbstract (sommario):
Rock burst, an important kind of geological disaster, often occurs in underground construction. Rock burst risk assessment, as an important part of engineering risk assessment, cannot be ignored. Liquid nitrogen fracturing is a new technology used in the geological, oil, and gas industries to enhance productivity. It involves injecting liquid nitrogen into reservoir rocks to induce fractures and increase permeability, effectively reducing rock burst occurrences and facilitating the flow of oil or gas toward the wellbore. The research on rock burst risk assessment technology is the basis of reducing rock burst geological disasters, which has important theoretical and practical significance. This article examines the temperature treatment of two types of rocks at 25 °C, 100 °C, 200 °C, 300 °C, and 400 °C, followed by immersion in a liquid nitrogen tank. The temperature difference between the liquid nitrogen and the rocks may trigger rock bursting. The research focused on analyzing various characteristics of rock samples when exposed to liquid nitrogen. This included studying the stress–strain curve, elastic modulus, strength, cross-section analysis, wave velocity, and other relevant aspects. Under the influence of high temperature and a liquid nitrogen jet, the wave velocity of rocks often changes. The structural characteristics and possible hidden dangers of rocks can be understood more comprehensively through section scanning analysis. The stress–strain curve describes the deformation and failure behavior of rocks under different stress levels, which can help to evaluate their stability and structural performance. The investigation specifically focused on the behavior of rocks subjected to high temperatures and liquid nitrogen. By analyzing the stress–strain curves, researchers were able to identify the precursors and deformation processes that occur before significant deformation or failure. These findings have implications for the mechanical properties and stability of the rocks.
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Sánchez-Delgado, N., L. Calleja, A. Rodríguez-Rey, A. Setién e V. G. Ruiz de Argandoña. "Revisión crítica de los ensayos de abrasividad en las rocas y de la influencia de las características petrográficas Critical review of abrasivity tests in rocks and the influence of the petrographic features". Trabajos de Geología 36, n. 36 (12 settembre 2018): 347. http://dx.doi.org/10.17811/tdg.36.2016.347-366.
Testo completoAbstract (sommario):
Resumen: La abrasividad de las rocas tiene gran influencia en algunas de sus aplicaciones, como en los sectores de la piedra natural y en el de ingeniería y obra civil. Para su cuantificación existen más de 15 métodos de ensayo. En este trabajo se hace una revisión de estos métodos clasificándolos en dos grandes grupos: en el caso de la piedra natural se considera el desgaste de los materiales rocosos en contacto con un útil de desgaste, mientras que, en obra civil, por el contrario, se presta atención al desgaste que la roca provoca en los útiles de corte o perforación. Por otra parte, se consideran también aquellos métodos en los que la abrasividad de las rocas se define en función de la variación del valor de alguna de sus propiedades.Palabras clave: Abrasividad, metodos de ensayo, rocas, propiedades fisicas, petrografia.Abstract: The abrasiveness of the rocks has a great influence in some of their applications, such as in the natural stone and in the civil engineering sectors. There are more than 15 test methods for its quantification. This work summarizes these methods and their classification into two large groups: in the case of natural stones the wear of the rock materials when in contact with a wear tool is taken into account; on the other hand, in civil engineering attention is paid to the wear that the rock causes in the cutting or drilling tools. In addition, those methods, in which the abrasiveness of rocks is defined according to the variation of the value of some of its properties, are also considered.Keywords: Abrasivity, testing methods, rocks, physical properties, petrography.
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Pegu, Ajanta. "Hydrocarbon Source Rock Analysis of Barail & Disang group". International Journal for Research in Applied Science and Engineering Technology 10, n. 5 (31 maggio 2022): 2305–12. http://dx.doi.org/10.22214/ijraset.2022.42814.
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Abstract: Petroleum source rocks are those which has sufficient amount of organic matter to generate and expel hydrocarbons to form a commercial accumulation of oil or gas. The objective of this project is to analyze the principal learning on the application of the formation of petroleum source rocks and hydrocarbon generation to exploration activities along with evaluation of petroleum source rocks and hydrocarbon generation. In this project, samples of Barail Group and Disang Group of rocks of Naga-Schuppen Belt were analyzed to determine their source rock characteristics and petroleum generative potentials Keywords: source rock, van Krevelen, Rock Eval pyrolysis, Hydrogen Index, Total organic Carbon content
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Zhang, Lei, Xufeng Wang, Zhijun Niu e Jianbo Dai. "Simulation Analysis of the Influence of Amplitude on Deformation and Fracture Characteristics of Hard Rock under Ultrasonic Vibration Load". Processes 12, n. 1 (28 dicembre 2023): 74. http://dx.doi.org/10.3390/pr12010074.
Testo completoAbstract (sommario):
The utilization of auxiliary tools employing ultrasonic high-frequency vibration to enhance rock breaking efficiency holds significant potential for application in underground hard rock excavation engineering. To investigate the failure mechanism of rocks under high frequency ultrasonic vibration load, this study employs particle flow software PFC2D for numerical simulation. By incorporating boundary conditions from actual ultrasonic vibration rock breaking experiments and utilizing a parallel bond model to construct the rock, we analyze the deformation, damage, fracture, and energy evolution process of hard rocks subjected to vibrational loads. The results demonstrate that the maximum displacement in hard rocks increases nearly linearly with vibrations until reaching 5.0199 × 10−3 m, after which it plateaus. Additionally, macroscopic fissures formed during rock failure exhibit an X-shaped pattern. Furthermore, based on our model, we examine the impact of amplitude variation on hard rocks with an equal number of cycles (5,000,000 cycles). Under ultrasonic vibration loads, amplitude influences the total input energy within the rock system. While increasing amplitude does not alter maximum deformation in rocks, it enhances fragmentation degree, fracture degree and energy dissipation coefficient—thereby improving rock breaking efficiency.
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Farida, Meutia, Moh Junaedy Burhan, Hamid Umar, A. M. Imran, Nur Ikhwana e Asmita Ahmad. "Sandstone Provenance of Walanae Formation as a Parent Rock in Bulukumpa area, Bulukumba Regency, South Sulawesi". Jurnal Ecosolum 12, n. 2 (31 dicembre 2023): 178–91. http://dx.doi.org/10.20956/ecosolum.v12i2.31432.
Testo completoAbstract (sommario):
The Walanae Formation has a wide distribution in the southern arm of Sulawesi, this rock formation was deposited during the formation of the basin due to the Walanae strike-slip fault. The Walanae Formation in the study area comprises sedimentary rocks and pyroclastic rocks, which give different soil characteristics. This study aims to determine the types of sandstones, rocks of origin, and provenance of sandstones in the study area by using spot sampling at representative stations and petrographic analysis. The sandstones of the study area are divided into two groups based on Folk (1974), namely arkose lithic and feldspathic litharenite. Based on the type of quartz, rock fragments, and associated minerals, the origin of the sandstones in the study area are plutonic igneous rocks, volcanic rocks, sedimentary rocks, and metamorphic rocks. The results show that the types of provenance sandstones in the study area are magmatic arc and recycled orogenic.
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Chung, Duk-Ho, e Kyeong-Jin Park. "Analysis of Earth Science Teachers’ Gaze Characteristics and Accuracy of Rock Identification According to the Level of Information Provided in the Metamorphic Rock Classification Process". Korean Association For Learner-Centered Curriculum And Instruction 23, n. 4 (28 febbraio 2023): 495–512. http://dx.doi.org/10.22251/jlcci.2023.23.4.495.
Testo completoAbstract (sommario):
Objectives The purposes of this study is to find out whether there is a difference in earth science teachers’ gaze characteristics and accuracy of rock identification according to the level of information provided in the metamorphic rock classification process.
Methods To this end, 6 samples of metamorphic rocks (phyllite, slate, gneiss, hornfels, marble, and schist) were selected, and by using them, tasks related to metamorphic rock classification with different levels of information were developed. Afterwards, the developed task was applied to 21 earth science teachers, and quantitative data on gaze movement in the process of classifying metamorphic rock was collected and analyzed using a eye tracker (Tobii Pro Glasses 2 model).
Results In the process of classifying metamorphic rocks, earth science teachers tended to focus too much on specific areas or unique features of the rock surface rather than the overall characteristics of the rock, and tended to classify rocks based on the limited information collected in this way. Second, although there are some differences depending on the type of rock, the more specific the information provided, the more the teachers’ total duration of fixation and number of fixation tended to decrease. Third, as the information provided was more specific, the accuracy of rock identification increased, and the types of rocks mentioned tended to decrease. Fourth, according to the level of information provided by earth science teachers, the most accurate pattern for classifying rocks was ‘wrong answer-wrong answer-correct answer’.
Conclusions Through the result of this study, it was confirmed that it is necessary to provide a systematic manual on matters to be paid attention to when observing the characteristics of metamorphic rocks, and to reduce the cognitive loads of learners through effective rock arrangement enhance understanding of metamorphic rocks classification.
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Ahrari-Roudi, Mohyeddin, e Mojtaba Zaresefat. "Armourstone Quality Analysis for Coastal Construction in Chabahar, Southeast Iran". Water 15, n. 1 (30 dicembre 2022): 151. http://dx.doi.org/10.3390/w15010151.
Testo completoAbstract (sommario):
Natural stones (armourstones) of varying sizes and qualities are frequently used to construct breakwaters to protect coastal engineering structures from wave actions for economic reasons. Time-related armourstone deterioration in the form of abrasion and disintegration may result in structural damage. Therefore, it is necessary to investigate the performance and quality of the armourstones, which should be robust and long-lasting. The study aimed to examine the quality of two distinct types of rocks from three breakwaters used as armourstones in the Chabahar region and compare the results to the observed field performance. This study aimed to illustrate why it is crucial to characterise rocks thoroughly before deciding which ones to use in a particular project and to evaluate how well current classification techniques account for the observed field performance of stones that may have complex geological compositions. The physical and mechanical properties of the rock were evaluated through both on-site observation and laboratory testing. The results indicated that the class of rocks used in the breakwater had a wide range of suitability ratings. It was discovered that sedimentary rocks have the best water absorption and porosity properties. In addition, age is a positive factor, as the rate of destruction decreases with age. Component and particle size can also play a role in lithology, which is a significant factor in the rock’s durability. Also, the findings demonstrated that the marine organisms in the rock component play an important role in the stability of these structures, even though rock mass breakwaters are less qualified for breakwater construction as per international coastal engineering standards. According to the findings, a breakwater made of lumachel rock boulders, or alternatively sandstone boulders, will last the longest.
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Ariansyah, Muhammad Resky, Muhammad Fawzy Ismullah Massinai e Muhammad Altin Massinai. "Rock Types Classification and Distribution on Anabanua Village, Barru Regency, South Sulawesi". Jurnal Geomine 8, n. 1 (27 giugno 2020): 1–8. http://dx.doi.org/10.33536/jg.v8i1.530.
Testo completoAbstract (sommario):
Anabanua Village, Barru Regency is one of the areas in South Sulawesi that has quite unique geological conditions. This condition inseparably comes from the complicated geological process that took place during the formation of the island, Sulawesi. In Anabanua Village, there are many types of rocks such as sedimentary rocks, metamorphic rocks and igneous rocks. This paper aims to map and classify the types of rock by taking samples on different places in the research area. Then we observe the samples physical properties. The results showed, from taking 10 rock samples in different places, they have various characteristics. 8 of them were sedimentary rocks, they are Limestone Quartz, Limestone Sand, Shale, Sandstone, Coal, Limestone Bioturbation, Breccia, and Chert Stone. The other 2 samples were metamorphic rocks, they are Greenschist and Quartzite.
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Muhammad, W. N., N. I. Setiawan, S. Husein e M. Nukman. "A preliminary study of geology and skarn of Cemorosewu Area, Bayat, Central Java, Indonesia". IOP Conference Series: Earth and Environmental Science 851, n. 1 (1 ottobre 2021): 012045. http://dx.doi.org/10.1088/1755-1315/851/1/012045.
Testo completoAbstract (sommario):
Abstract We present the first finding of skarn rocks in Cemorosewu area of East Jiwo Hill, Bayat, Central Java, Indonesia. The geological conditions of this area which related to the appearance of the skarn is also reported. The methods used in this research are DEM acquisition using drone to generate basemap for geological mapping and thin section petrographic analyses. The geological map shows that Cemorosewu area consists of metamorphic rocks (mica phyllite, graphite phyllite, with quartzite and marble lenses), sedimentary rocks (carbonate breccia and siltstone), and igneous rock (microdiorite). Based on the field observation and geological map, the regional metamorphic rocks are the oldest units in this area followed by sedimentary rocks and igneous rock which intruded both rocks. Skarn rocks were cropped out as a boulder along the Kluwihan creek with the maximum size of 8 m in length. The skarn consists of garnet, clinopyroxene, zoisite, actinolite, and minor quartz. Metasiltstone and skarn rock are suggested formed by contact metamorphism of microdiorite intrusion. The marble, which lenses within the phyllites, is suggested to be the protolith of the skarn formation in this area.
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Titamgim, R. Dirk. "Questions and Answers about Rocks: Rock Chips: How Should Rocks Be Labeled?" Rocks & Minerals 63, n. 5 (settembre 1988): 407. http://dx.doi.org/10.1080/00357529.1988.11761873.
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Titamgim, R. Dirk. "Questions and Answers about Rocks: Rock Chips: Are There Rocks That Bend?" Rocks & Minerals 67, n. 3 (giugno 1992): 194–98. http://dx.doi.org/10.1080/00357529.1992.9926483.
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Sengupta, Mita, e Shannon L. Eichmann. "Computing elastic properties of organic-rich source rocks using digital images". Leading Edge 40, n. 9 (settembre 2021): 662–66. http://dx.doi.org/10.1190/tle40090662.1.
Testo completoAbstract (sommario):
Digital rocks are 3D image-based representations of pore-scale geometries that reside in virtual laboratories. High-resolution 3D images that capture microstructural details of the real rock are used to build a digital rock. The digital rock, which is a data-driven model, is used to simulate physical processes such as fluid flow, heat flow, electricity, and elastic deformation through basic laws of physics and numerical simulations. Unconventional reservoirs are chemically heterogeneous where the rock matrix is composed of inorganic minerals, and hydrocarbons are held in the pores of thermally matured organic matter, all of which vary spatially at the nanoscale. This nanoscale heterogeneity poses challenges in measuring the petrophysical properties of source rocks and interpreting the data with reference to the changing rock structure. Focused ion beam scanning electron microscopy is a powerful 3D imaging technique used to study source rock structure where significant micro- and nanoscale heterogeneity exists. Compared to conventional rocks, the imaging resolution required to image source rocks is much higher due to the nanoscale pores, while the field of view becomes smaller. Moreover, pore connectivity and resulting permeability are extremely low, making flow property computations much more challenging than in conventional rocks. Elastic properties of source rocks are significantly more anisotropic than those of conventional reservoirs. However, one advantage of unconventional rocks is that the soft organic matter can be captured at the same imaging resolution as the stiff inorganic matrix, making digital elasticity computations feasible. Physical measurement of kerogen elastic properties is difficult because of the tiny sample size. Digital rock physics provides a unique and powerful tool in the elastic characterization of kerogen.
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Uchida, Etsuo, e Takumi Yokokura. "Differences in Geochemical Characteristics and Tectonic Settings between Hai Van Granitic Rocks in Da Nang Province and Van Canh Plutonic Rocks in Quang Nam Province, Central Vietnam". Geosciences 14, n. 1 (31 dicembre 2023): 13. http://dx.doi.org/10.3390/geosciences14010013.
Testo completoAbstract (sommario):
Research was conducted on plutonic rocks, previously referred to as the Hai Van granitic rocks, distributed in Da Nang and Quang Nam provinces in Central Vietnam. The granitic rocks in Da Nang Province have low magnetic susceptibilities and have geochemical signatures typical of S-type. Additionally, a negative Eu anomaly suggests that the source rock is an organic matter-bearing sedimentary rock. The granitic rocks were likely formed during the collision between the Indochina and South China blocks. In contrast, plutonic rocks in Quang Nam Province have high magnetic susceptibilities and have geochemical signatures of I-type. No Eu anomaly was observed, and they are adakitic rocks in nature. Based on these findings, the plutonic rocks in Quang Nam Province are distinctly different from the Hai Van granitic rocks in Da Nang Province, but they are Van Canh plutonic rocks. The Hai Van granitic rocks in Da Nang Province and the Van Canh plutonic rocks in Quang Nam Province are located in the Truong Son Fold Belt. The Van Canh plutonic rocks are located farther away from the Song Ma Suture Zone than the Hai Van granitic rocks. The Van Canh plutonic rocks were generated due to the subduction of the hot Song Ma Ocean beneath the Indochina Block. The Hai Van granitic rocks are understood to have been generated in a compressional field where the Song Ma Ocean was pushing against the Indochina Block; however, the Van Canh plutonic rocks are supposed to have been generated in an extensional field, like in a back-arc-like environment generated by the subduction of the Song Ma Ocean beneath the Indochina Block.