Artículos de revistas sobre el tema "Artificial and natural clay"
Siga este enlace para ver otros tipos de publicaciones sobre el tema: Artificial and natural clay.
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores artículos de revistas para su investigación sobre el tema "Artificial and natural clay".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Ward, PR y JM Oades. "Effect of clay mineralogy and exchangeable cations on water repellency in clay-amended sandy soils". Soil Research 31, n.º 3 (1993): 351. http://dx.doi.org/10.1071/sr9930351.
Texto completoResumen
Artificial water-repellent sands were prepared in the laboratory from acid-washed sand and either cetyl alcohol or organics extracted from a natural water-repellent sand. Added clays (at 0.5% w/w) had no effect when gently mixed with a natural and the two artificial water-repellent sands. After a wetting and drying cycle, kaolinite reduced repellency to a low level in the natural sand and the artificial sand with extracted organics, but montmorillonite was not effective. Na+-saturated clays were generally more effective than Ca2+-saturated clays. In the cetyl alcohol sand, montmorillonite was more effective than kaolinite. Neither artificial sand was a perfect model of the natural system, although the extracted organic model was far superior. Kaolinite did not strongly adsorb hydrophobic molecules, but was effective because it was able to cover the hydrophobic sand surface. Application of kaolinite clay to a water-repellent sand appears promising.
2
Shan, Yi, Xing Wang, Jie Cui, Haihong Mo y Yadong Li. "Effects of Clay Mineral Composition on the Dynamic Properties and Fabric of Artificial Marine Clay". Journal of Marine Science and Engineering 9, n.º 11 (3 de noviembre de 2021): 1216. http://dx.doi.org/10.3390/jmse9111216.
Texto completoResumen
Marine clays are easily affected by different mineral composition in cyclic load-based geological hazards. Therefore, based on analyzing the mineral composition of natural marine clay, it is the key to predict the dynamic properties of natural materials under cyclic loading by using quantitated artificial marine clay. In this study, the marine clay found in the South China Sea deltas was investigated. Based on the results of geological conditions and mineral composition analyses, raw non-clay minerals (such as quartz, albite) and clay minerals (such as Na-montmorillonite and kaolinite) were used to produce artificial marine clay, the dynamic properties of which were studied from the impact of mineral composition. Dynamic triaxial laboratory testing for artificial marine clay comprising various clay minerals was performed under identical test conditions. The artificial marine clay with high montmorillonite content exhibited slower development of strain, more sluggish growth in pore water pressure, more rounded hysteresis curves, greater stiffness, and more prolonged viscous energy growth than the clay with low montmorillonite content. In addition, the flocculated fabric of the artificial marine clay with high montmorillonite content demonstrated sufficient pore space changes, more uniform pore distribution, and larger specific surface area than the dispersed fabric of the clay with low montmorillonite content. The factors arising from the influence of montmorillonite may lead to microstructural and fabric changes, hinder the development of pore water, and increase intergranular contact stiffness as well as delay the cyclic strain amplitude at the breakpoint of viscous energy dissipation. In general, the results presented in this study confirm that clay minerals, especially montmorillonite, have significant influence on the dynamic properties of large strain.
3
Siepmann, R., F. von der Kammer y U. Förstner. "Colloidal transport and agglomeration in column studies for advanced run-off filtration facilities - particle size and time resolved monitoring of effluents with flow-field-flowfractionation". Water Science and Technology 50, n.º 12 (1 de diciembre de 2004): 95–102. http://dx.doi.org/10.2166/wst.2004.0700.
Texto completoResumen
The efficiency of road run-off filtration facilities based on ion-exchange materials is reduced by pollutants which are transported bound to particles. To quantify the factors governing particle transport phenomena, a simplified model consisting of quartz sand-filled columns representing the filter/soil was set up. Suspensions of artificial clays, cold water-extracted natural clays, and real run-off were used as model effluents. Five experiments were performed: breakthrough of a natural soil suspension, remobilization of a natural soil suspension after ionic strength-drop, the same two experiments with a suspension of the artificial clay mineral Laponite, and the remobilization of run-off accumulated on a column at high ionic strength with an ionic strength down-gradient. Short-interval effluent fractions were analysed by flow-field-flowfractionation (F4) to obtain the size distributions of the colloids present. The size distributions of subsequent fractions were then plotted in a staggered arrangement to give three-dimensional graphs that are time- and particle size-resolved. With this method the subsequent release of different agglomerate sizes formed on the column could be shown for the artificial clay mineral, questioning its use as a model colloid. The combined particle size- and time-resolved plots proved to be a powerful tool for monitoring colloidal solids in column effluents.
4
Tsetlin, Yu B. "The Origin of Pottery as a Result of Human Adaptive and Imitative Activity". Bulletin of the Irkutsk State University. Geoarchaeology, Ethnology, and Anthropology Series 41 (2022): 113–21. http://dx.doi.org/10.26516/2227-2380.2022.41.113.
Texto completoResumen
The study of the origin of pottery production includes a consideration of two important questions: 1) Why pottery production appeared? and 2) How it was? In European and American archaeological literature, we can find various approaches to these issues. This article proves the fact that pottery production appeared in the result of gradual accumulation of concrete human knowledge about the useful features of different natural materials distributed in the environment. The all useful knowledge in pottery making was found only by cut-and-try method. It was a long-time and step by step process, when positive acquirements became a part of local cultural traditions which passed down from generation to generation. Resemblance between stone, wicker, and clay vessels in general proportionality and volume shows that the emergence of pottery was an obligate course of development, when different natural materials were tested. The process had been finished by widespread distribution of clay vessels as universal things by their function. Since the emergence of pottery production was a polycentric process, a concrete ways of pottery technology development were different in various natural and climatic conditions. But in any cases, this process obeyed general laws, which are consisted in gradual knowing about important qualities of silt and then of clay plastic raw materials. The change from silt to clay was manifested itself in special imitation of complex constituent of silt by adding of different organic or mineral tempers in natural clay. The author shows that the development of vessels’ shapes passed from the use of natural containers then to artificial containers made of natural materials, and finally to artificial ones made of new special constructional materials (i.e., pottery pastes). Such clay containers could be fired with various regimes. So, we can do a conclusion, that the origin of pottery production was an obligate historical process of human adaptation to the natural environment, its imitation, and finally to the making a new artificial material which are absent in the world.
5
Ratajczak, Tadeusz, Elżbieta Hycnar y Piotr Bożęcki. "The beidellite clays from the Bełchatów lignite deposit as a raw material for constructing waterproofing barriers". Gospodarka Surowcami Mineralnymi 33, n.º 2 (27 de junio de 2017): 53–67. http://dx.doi.org/10.1515/gospo-2017-0014.
Texto completoResumen
Abstract Disposal sites for both industrial and communal waste are hazardous for the natural environment due to the accumulated materials and their chemical, physical and biological transformations. The products of these processes migrating at a significant distance contaminate mainly underground waters, surface waters and soils. The spreading of the pollutants may be prevented by horizons of clay rocks that form natural geological barriers. The clay rocks of properly selected parameters may be used in the environmental engineering for constructing artificial water-sealing layers. The mineral, chemical, physico-chemical and physico-mechanical properties of the beidellite clays occurring within the lignite deposit in Bełchatów were studied to find out whether they meet the criteria of waterproofing engineering contained in the Polish recommendations and instructions. The results indicate that the beidellite clays of Bełchatów are rocks suitable for this kind of environmental engineering and may be used in constructing the barriers preventing the migration of effluents from landfills.
6
Yin, Kexin, Anne-Laure Fauchille, Eugenia Di Filippo, Khaoula Othmani, Samuel Branchu, Giulio Sciarra y Panagiotis Kotronis. "The Influence of Mixing Orders on the Microstructure of Artificially Prepared Sand-Clay Mixtures". Advances in Materials Science and Engineering 2021 (10 de septiembre de 2021): 1–15. http://dx.doi.org/10.1155/2021/8552224.
Texto completoResumen
The mixing order of silica sand, clay (kaolinite), and water controls the microstructure of resulting artificial soil samples. Most homogeneous microstructures can be achieved by applying the mixing order “sand-water-clay.” The following methods were used to validate this statement: (1) optical observation, (2) X-ray tomography, (3) scanning electron microscopy, and (4) Mercury intrusion porosimetry. For all samples, clays are mainly organized in a homogeneous matrix but are also dispersed heterogeneously in micrometer-sized layers surrounding sand particles, particularly where sand grains show a greater roughness. At water contents ≥1.5 w L , the microstructures are visually similar from the mm to μm scale whatever mixing order is used. However, for water contents lower than 1.5 w L , the mixing order controls the distribution of the clay particles. This paper proposes a motivated choice of a preparation protocol of artificial clayey materials to be used in laboratory experiments. It might contribute to better understanding and modeling grain movements and arrangements in artificial muds, used for instance in underground mining, foundation settlement, hydraulic containment, road construction, soil stabilization, and in natural soils in the occurrence of soil liquefaction, industrial brick manufacturing, and in studying shear processes in tectonic fault zones.
7
Zhou, Jian Mei. "Study on Application of Artificial Sand in Ready-Mixed Concrete". Advanced Materials Research 800 (septiembre de 2013): 40–43. http://dx.doi.org/10.4028/www.scientific.net/amr.800.40.
Texto completoResumen
Artificial sand can be obtained by mixing washed sand formed from the the poor quality of natural sand with high clay content and stone powder formed from processing and screening production by appropriate ratio, Which be applied to C20~C35 ready-mixed concrete. By studying the effect the artificial sand on the properties of fresh concrete and concrete after hardening, the result showed that artificial sand substitute for natural sand as ready-mixed concrete fine aggregate is entirely feasible. Key words: Artificial sand, Ready-mixed concrete, Property
8
Abbey, Samuel J., Eyo U. Eyo y Colin A. Booth. "Using Artificial Intelligence Techniques to Predict Intrinsic Compressibility Characteristic of Clay". Applied Sciences 12, n.º 19 (2 de octubre de 2022): 9940. http://dx.doi.org/10.3390/app12199940.
Texto completoResumen
Reconstituted clays have often provided the basis for the interpretation and modelling of the properties of natural clays. The term “intrinsic” was introduced to describe a clay remoulded or reconstituted at moisture content up to 1.5 times its liquid limit and consolidated one-dimensionally. In order to circumvent the difficulties of measuring an intrinsic constant called “intrinsic compressibility index” (C*c), a machine learning (ML) approach using traditional non-parametric tree-based and meta-heuristic ensembles was adopted in this study. Results indicated that tree-ensembles namely random decision forest (RDF) and boosted decision tree (BDT) performed better in C*c prediction (average R2 of 0.84 and root mean square error, RMSE of 0.51) compared to stand-alone models. However, models’ hyper parameters combined meta-heuristically, produced the highest accuracy (average R2 of 0.90 and root mean square error, RMSE of 0.34). The greatest capacity to distinguish between positive and negative soil classes (average accuracy of 0.95, precision and recall of 0.86) were demonstrated by meta-ensembles in multinomial classification.
9
Arkin, Yaacov y Lucian Michaeli. "Strength and consistency of artificial clay — carbonate mixtures: Simulation of natural sediments". Engineering Geology 26, n.º 3 (marzo de 1989): 201–13. http://dx.doi.org/10.1016/0013-7952(89)90009-4.
Texto completo
10
Deslouis, C., P. Falaras, O. Gil, M. Jeannin, V. Maillot y B. Tribollet. "Influence of clay on calcareous deposit in natural and artificial sea water". Electrochimica Acta 51, n.º 15 (abril de 2006): 3173–80. http://dx.doi.org/10.1016/j.electacta.2005.09.006.
Texto completo
11
Wang, Xiao Yun y Ai Min Fu. "Study on Sediment Characteristics in Artificial Wetland and Natural Wetland". Advanced Materials Research 599 (noviembre de 2012): 748–52. http://dx.doi.org/10.4028/www.scientific.net/amr.599.748.
Texto completoResumen
This paper studied the sidemen characteristics of artificial wetland and natural wetland by cumulant, sedimentary organic matter, DOC and nitrate content. The results showed that the sediments in artificial wetlands upper layer were instable and uncompacted and often had trouble collecting for various factors .which was different from in natural wetland. Artificial wetland must pass through the months and years pass by. Time operation due to be texture, cation exchange capacity and clay changes, resulting in increasing content of organic substances. Natural wetland sediments of dissolved organic carbon in a constructed wetland system is high and the overall performance is relatively stable. But nitrate content was higher and less stable than the constructed wetland sediments.
12
Li, Dongqing, Jianxin Wei, Bangrang Di, Da Shuai, Lihui Tian y Pinbo Ding. "Effect of fluid saturation on the shear modulus of artificial clay-rich tight sandstones". Geophysical Journal International 222, n.º 1 (23 de abril de 2020): 15–26. http://dx.doi.org/10.1093/gji/ggaa124.
Texto completoResumen
SUMMARY For many geophysical problems it is important to understand the influence of clay on the elastic behaviour of the rocks. However, this is difficult to measure because the complex petrophysical characteristics of tight sandstones make it challenging to control the clay parameters in natural samples. In this study, we synthesized nine tight sandstones with different clay types and content. Ultrasonic measurements and theoretical simulations were then used to analyse the influence of clay on the elastic modulus of brine saturated samples. We found that the shear modulus of smectite-rich samples decreased drastically after saturation, while the decrease observed in kaolinite-rich samples was relatively low. We propose that the reduction in surface energy caused by surface-particle clay hydration is a common mechanism that leads to shear softening in both kaolinite-rich and smectite-rich samples. However, the contact deformation caused by cation hydration of smectite is the primary mechanism leading to greater shear softening of tight sandstones containing smectite. Although the differential Kuster–Toksöz model is based on idealized pore shapes, a dual-porosity scheme can be used to explain and simulate the shear softening of artificial clay-rich tight sandstones.
13
Jia, Chao, Wenbo Cui, Lifeng Dong, Ruchun Wei, Hongyuan Ma y Pengpeng Ding. "Research on the Initial Settlement Depth of Artificial Reef on the Clay Seabed". Highlights in Science, Engineering and Technology 25 (13 de diciembre de 2022): 160–64. http://dx.doi.org/10.54097/hset.v25i.3460.
Texto completoResumen
The artificial reef is an artificial structure that simulates some characteristics of a natural reef. Its penetration depth in the seabed soil affects the stability of the reef on the seabed. In this paper, based on the CEL (Coupled Eulerian-Lagrangian analysis) method, a finite element model is established for the process of artificial reef entry and penetration, which simulates the speed change law of the artificial reef in the water and the penetration depth in the clay seabed, and The study analyzed the influence of different reef weights, penetration speeds, and seabed soil properties on the penetration depth of artificial reefs.
14
Barber, Nicholas A. "Clay Caterpillars: A Tool for Ecology & Evolution Laboratories". American Biology Teacher 74, n.º 7 (1 de septiembre de 2012): 513–17. http://dx.doi.org/10.1525/abt.2012.74.7.15.
Texto completoResumen
I present a framework for ecology and evolution laboratory exercises using artificial caterpillars made from modeling clay. Students generate and test hypotheses about predation rates on caterpillars that differ in appearance or “behavior” to understand how natural selection by predators shapes distribution and physical characteristics of organisms.
15
Kedi, Atolé Brice Bienvenu, Seka Simplice Kouassi, Vamoussa Coulibaly y Joseph Sei. "Elimination de polluants des déchets liquides d’une unité de production de sucre par des argiles naturelles de Côte d’Ivoire". International Journal of Biological and Chemical Sciences 15, n.º 2 (23 de junio de 2021): 803–15. http://dx.doi.org/10.4314/ijbcs.v15i2.31.
Texto completoResumen
L’impact des déchets liquides industriels sur l’environnement demeure une réalité et une menace pour la qualité des eaux souterraines et de surfaces. Parmi les méthodes de dépollution existantes, l’adsorption des polluants par les argiles naturelles reste une méthode moins couteuse, disponible et facilement utilisable. La plupart des études sur l’aptitude des argiles à éliminer les polluants est faite avec des déchets liquides artificiels dont les concentrations sont maitrisées. L’objectif de cette étude était d’éliminer les polluants dans les déchets liquides d’une unité industrielle agronomique (UIA) de production de sucre par deux argiles naturelles de Côte d’Ivoire. Trois sources de déchets liquides provenant des activités de laboratoire d’analyse des sols, de jus de canne et de canne à sucre de l’UIA. Le traitement aux argiles a montré des taux d’élimination à divers degrés des polluants. Les paramètres suivants ont été mesuré avant et après le traitement aux argiles : pH, conductivité, turbidité, phosphore total, azote total, cuivre, zinc, plomb et mercure. L’argile de Katiola présente des aptitudes plus élevées à éliminer les polluants, comparée à l’argile d’Anyama. Cette étude confirme l’intérêt de l’utilisation des argiles pour la dépollution.Mots clés : Eaux usées, métaux lourds, pollution, argiles, adsorption.
English title: Removal of liquid waste pollutants from a sugar production unit using natural clays from Côte d'IvoireThe impact of industrial liquid waste on the environment remains a reality and a threat to groundwater and surface water quality. Among the existing depollution methods, the pollutants adsorption on natural clays remains a less expensive, available and easily usable method. Most studies on the ability of clays to remove pollutants are done with artificial liquid wastes whose concentrations are controlled. The objective of this study was to eliminate the pollutants in the liquid waste of an industrial agronomic sugar production unit using two natural clays from Côte d'Ivoire. Three sources of liquid wastes from the UIA's analysis laboratory activities. Treatment with clays showed varying degrees of removal of pollutants. The following parameters were measured before and after the clay treatment: pH, conductivity, turbidity, total suspended solids, total phosphorus, total nitrogen, copper, zinc, lead and mercury. The values of these parameters are compared to the national standard. Katiola clay exhibits higher abilities to remove pollutants compared to Anyama clay. This study confirms the value of using clays for depollution.Keywords: Wastewater, heavy metals, pollution, clays, adsorption.
16
Selin, D. V. y Yu P. Chemyakin. "Pottery of the Kalinkino Culture from the Barsov Gorodok III/2 Settlement: Technical and Technological Characteristics". Vestnik NSU. Series: History and Philology 22, n.º 3 (5 de marzo de 2023): 72–84. http://dx.doi.org/10.25205/1818-7919-2023-22-3-72-84.
Texto completoResumen
Purpose. Barsova Gora is a unique archaeological and landscape site located in the Tyumen Region (West Siberia) of the Russian Federation. The technical and technological analysis of Kalinkino ceramics from the Barsov gorodok III/2 settlement (25 vessels) was performed in accordance with the method developed by A. A. Bobrinsky.Results. For the manufacture of vessels at the Barsov gorodok III/2 settlement, ferruginous clays were selected. Five subspecies of clay have been identified, differing in the sandiness degree and natural impurities composition. The most common subspecies of clay is weakly sandy clay with natural inclusions of brown ironstone. Three recipes for molding compond were defined: 1) clay + chamotte (21 vessels); 2) clay + chamotte + sand (3 vessels); 3) clay + sand (1 vessel). Vessels were made using patchwork molding, presumably on a base mold. Surfaces of vessels were processed by mechanical smoothing and glossing. There are 10 variants of combining different tools. The most common variant is smoothing vessel both surfaces using a serrated tool. Firing of pottery could take place in reducing or semireducing gas environment.Conclusion. A comparison of pottery traditions of the Kalinkino culture from the Barsov gorodok III/2 settlement and the Barsova Gora III/20 settlement revealed their similarity. It is manifested in the selection of weakly sandy ferruginous clays for vessels production. The dominant recipe for molding compound on both sites is clay + chamotte. Vessels were made using patchwork overlay. There are differences in the range of artificial additives used in the ceramic production, recipes for molding compound, surface treatment options. Pottery of the Kalinkino culture from the Barsov Gorodok III/2 settlement demonstrates similarity with the Barsovo culture products. The similarity is manifested in the use of weakly sanded ferruginous clays and the use of chamotte as the main mineral impurity. It also converges with the pottery of the Surgut variant of the Kulay cultural-historical community due to use of chamotte and patchwork overlay. However, there are significant differences between ceramics of the Surgut variant of the Kulay cultural-historical community and the Kalinkino culture from the Barsov gorodok III/2 settlement manifested: it lies in the use of shadings and flap veneer in the Kulay pottery.
17
Zvikelsky, Ori, Noam Weisbrod y Avraham Dody. "A comparison of clay colloid and artificial microsphere transport in natural discrete fractures". Journal of Colloid and Interface Science 323, n.º 2 (julio de 2008): 286–92. http://dx.doi.org/10.1016/j.jcis.2008.04.035.
Texto completo
18
Umoh, John. "Understanding Clay Contamination as a Basic Step to Successful Ceramics Practice". International Journal of Innovative Research in Arts, Education and Technology 2, n.º 1 (1 de enero de 2021): 57–66. http://dx.doi.org/10.48028/iiprds/ijiraet.v2.i1.06.
Texto completoResumen
Clay as a product of igneous rock has over the centuries been the major material in ceramics production. Whether it is collected from its place of formation or its secondary location is not without other materials that have come in contact with. These materials otherwise referred to as contaminants can mar or enhance the performance of clay. The aim of this paper is to highlight the effects of clay contaminants in ceramic practice. The objectives will be, to look at the formation and types of clay, the contaminants and their functions in ceramics production, the natural and artificial contaminants and modifiers in clay body formulation. The truth is that over the years, potters have not really considered clay contaminants as basic ingredients for successful ceramic practice. Data collect from primary and secondary sources will help in the proper understanding of clay contamination and its role in successful ceramics practice.
19
Asamatdinov, Marat, Andrey Medvedev, Alexey Zhukov, Ervand Zarmanyan y Alexey Poserenin. "Modeling of the composition of ecologically safe clay-gypsum binders". MATEC Web of Conferences 193 (2018): 03045. http://dx.doi.org/10.1051/matecconf/201819303045.
Texto completoResumen
Clay-gypsum of each deposit are ecologically safe natural materials. They differ from others in their mineralogical and phase composition, they have different properties. Such a spread of properties of natural clay-gypsum, including after their heat treatment, makes it difficult to process them and, ultimately, use. The factor of "unpredictability of the obtained results" is one of the reasons why this type of natural composites are practically not used in modern construction. The paper presents the results of studies of the properties of model compositions of a clay-gypsum binder. The theoretical basis of the research is the methodology for the creation of new building materials, developed at the MSUCE. According to the proposed provisions, the properties of composite (or multicomponent) systems can be evaluated using the concept of a model body, in our case a "model material", manufactured with observance of certain technological parameters. According to the results of the first stage, the optimum temperature for calcination of an artificial clay-gypsum binder (which was 230-250°C) was established, and a graphical interpretation of the results was carried out using triple diagrams. By results of researches it is established, that the majority of natural structures in the natural state, or after modification can be used as a basis for reception of interior plaster mixes.
20
Mathé, V., A. Meunier y F. Lévêque. "Anthropic acceleration of a natural clay mineral reaction in marshland soils (Atlantic Coast, France)". Clay Minerals 42, n.º 1 (marzo de 2007): 1–12. http://dx.doi.org/10.1180/claymin.2007.042.1.01.
Texto completoResumen
AbstractSoil clay minerals in recent natural polders react on a human timescale in response to local environmental conditions. With increasing age, the mineral reaction leads to the dissolution of the chlorite component and a composition change of the different illite-smectite mixed-layer minerals (I-S MLMs): i.e. smectite layer content decreases and illite content increases. The process of oxidation, which is proven by magnetic susceptibility to trigger clay mineral reaction, changes the mineralogical composition of the sediment above the redox front. The mineral changes appear to be a non-linear function of time. In natural conditions the process lasts >1000 y. However, anthropoic forcing such as artificial drainage accelerates the oxidation reaction to complete the whole process in a few tens of years.
21
Wang, Xiuyu, Chuanying Zhang y Guorui Sun. "Investigation on Swelling Performance of Oil Sands and Its Impact on Oil Production during SAGD Processes". Energies 15, n.º 18 (15 de septiembre de 2022): 6744. http://dx.doi.org/10.3390/en15186744.
Texto completoResumen
SAGD (Steam Assisted Gravity Drainage) is used in Canadian fields where there are interlayers that impede steam chamber development and thus impede production. Many experiments have been conducted on the effect of interlayers on oil recovery. However, the swelling characteristics of interlayers under different conditions, as well as the possible clay mineral transformation and particle migration of clay particles at high temperatures, are rarely studied. In this paper, the swelling characteristics of natural oil sands and artificial clay samples were studied by high temperature hydration swelling experiments to obtain a better comparison. The effects of temperature, pressure and solution type on the swelling rate of oil sand were studied. The uniaxial compressive strength of the core in the presence of clay was studied by the scribe test. In addition, before and after the aging test at 220 °C and 2.5 MPa, the clay mineral composition was studied by the X-ray diffraction method, and the mineral transformation was proved. Finally, the impact of clay swelling on oil production is investigated by simulating the particle migration effect while considering the swelling effect. The results show that the swelling rate of oil sand increases with the increment of temperature and the decrement of pressure. The swelling rate of an artificial clay sample in distilled water is the highest, while a 1% KCl + 1% CaCl2 solution has the best swelling inhibition effect. This study aims to provide new insights into reservoir damage research during SAGD development.
22
Pivinskiy, Yu E., V. A. Doroganov y E. A. Doroganov. "Cement free castable. Part 6. Comparative assessment of natural (clay) and artificial ceramic binders (HCBS)". NOVYE OGNEUPORY (NEW REFRACTORIES), n.º 9 (25 de octubre de 2020): 25–31. http://dx.doi.org/10.17073/1683-4518-2020-9-25-31.
Texto completoResumen
A comparative assessment of artificial (based on highly concentrated ceramic binders suspensions - HCBS) and natural (based on clays and kaolins) ceramic binders of similar composition has been carried out. Analysis of their properties and characteristics shows both their significant similarity and significant difference. As with HCBS, the binding (strength) properties of clays and kaolins are determined by the content of colloidal particles and nanoparticles in them. In contrast to HCBS, clays and kaolins are characterized by a significant content of chemically bound water, a high water requirement of molding systems, and a sharp, different (by an order of magnitude and higher) shrinkage during drying. If binders based on clays are considered from the position of HCBS classification, then according to their chemical composition they can be classified as acid-amphoteric (like materials based on chamotte). However, in terms of chemically bound water, volumetric concentration of the suspension, they are closer to HCBS of amphoteric and basic compositions. The addition of refractory clays and kaolins is very effective in the production of ceramic concrete.
23
Purwana, Yusep Muslih, Bambang Setiawan, Raden Harya Danajaya y Brilliant Bagaskara. "PRELIMINARY STUDY ON PLASTICINE AS A SUBSTITUTE COHESIVE MATERIAL FOR GEOTECHNICAL PHYSICAL SOIL MODELING". Jurnal Riset Rekayasa Sipil 4, n.º 2 (10 de marzo de 2021): 53. http://dx.doi.org/10.20961/jrrs.v4i2.49197.
Texto completoResumen
<p>Plasticine is an artificial material made from solids such as gypsum, lime, mixed with petroleum jelly or micro wax and acid fat. The properties of plasticine are likely similar to natural clay and is influenced by oil content. The information about mechanical properties of plasticine is still very rare, and as such the study on it is riquired and must be conducted intensively. The preliminary laboratory study has been conducted to understand the behaviour of plasticines. Microwax and petroleum jelly based plasticines were utilised with the variation of oil content, whereas kaolin clay with the variation of water content is utilised as a reference material. The study is focusing on the stress-strain behaviour for both microwax and petroleum jelly based plasticines compared to the stress-strain behaviour of kaolin clay. This paper reports the result of preliminary investigation regarding the use of plasticine as an alternative artificial material for substitution of clay in soil modeling. Some engineering properties from unconfined compression strength (UCS) test and hand penetrometer are shown. The result indicates that the stress-strain behaviour of plasticine resembles the stress-strain behaviour of kaolin clay. The plasticine is suitable as a substitute cohesive material and it has a potential to be utilised for geotechnical material modelling in the future.</p>
24
Watanabe, Eiji, Kaori Nishizawa y Masaki Maeda. "Relationship between Chemical Composition and the Amount of Phosphorus Adsorbed". Materials Science Forum 695 (julio de 2011): 141–44. http://dx.doi.org/10.4028/www.scientific.net/msf.695.141.
Texto completoResumen
Relationship of the adsorption behaviors of phosphorus with several natural materials and artificial HAS-clay with various chemical compositions was investigated. The amounts of phosphorus adsorbed by them were closely related with the contents of aluminum in the material. It was found that the higher the aluminum contents of material, larger the amount of phosphorus were adsorbed.
25
Ketrot, D., A. Suddhiprakarn, I. Kheoruenromne y B. Singh. "Interactive effects of iron oxides and organic matter on charge properties of red soils in Thailand". Soil Research 51, n.º 3 (2013): 222. http://dx.doi.org/10.1071/sr13021.
Texto completoResumen
Iron (Fe) oxides and organic matter (OM) play important roles in maintaining the fertility of highly weathered soils. The main objective of this study was to investigate the interactive effects of variable surface charge minerals, particularly Fe oxide minerals, and OM on the charge properties of red soils from Thailand. We also evaluated the effect of the 5 m NaOH procedure, used to concentrate Fe oxides from soils, on the charge characteristics of Fe oxide concentrates. Fourteen clay fractions (untreated and OM-free clay fractions), and Fe oxide concentrates of these clays, were used in the study. Cation exchange capacity (CEC) and electrophoretic mobility (EM) were measured for the soil clays, artificial mixtures, and goethite adsorbed with humic acid (HA) and phosphate (P). Kaolinite and Fe oxides (predominantly a mixture of hematite and goethite) were the main minerals in the clay fraction. Results indicated that OM or metal–OM complexes may have blocked or neutralised negatively charged sites on clay minerals. After OM removal these sites became accessible, inducing an increase in CEC and shifting the EM values towards more negative values and the isoelectric point (IEP) towards lower pH for many samples. The CEC values of Fe oxide concentrates prepared by 5 m NaOH treatment were overestimated and their EM and IEP shifted towards more negative values. It is possible that the amorphous phase from clay dissolution was still present in the Fe oxide concentrates, or the adsorption of silicate ions modified the surfaces of Fe oxides concentrates. Humic acid and P adsorbed on Fe oxide surfaces caused the IEP to shift to lower values. In natural soil conditions, a variety of anions can be adsorbed on Fe oxide surfaces, which might lead to higher values of negative charge and lower IEP than observed for pure synthetic minerals.
26
Boychuk, O. V., Ye S. Pletenets y K. D. Pershina. "Thermoelectric properties of the modified natural aluminosilicates". Voprosy Khimii i Khimicheskoi Tekhnologii, n.º 6 (diciembre de 2023): 13–24. http://dx.doi.org/10.32434/0321-4095-2023-151-6-13-24.
Texto completoResumen
Natural layered bentonite and its artificial modifications have attracted growing interest in converting low-grade thermal energy into electricity. However, a substantial improvement in the thermoelectrical performance of modified clay remains a significant challenge. Modification is one way to solve the rising thermoelectrical efficiency of clays. Natural bentonite is a promising material for modifications by phosphate ions and magnetite because it is easily prepared in the water media. Such modifications demonstrated high thermoelectrical performance (increasing the Seebek coefficient by two times), thermostability, and durability. IR spectroscopy, X-ray diffraction analysis, atomic absorption spectroscopy, surface area measurements, SEM microscopy, and electrochemical impedance spectroscopy measurements have given the possibility to detect differences in the thermoelectric behavior of the natural and modified bentonite. Magnetite in bentonite enhances the Seebeck coefficient via localization of charge distribution and change in the size of pores, enlarging the non-linear distribution of the electrostatic capacitance due to changing the distribution of the absorbed water, surface, and structure's OH– groups in the natural bentonite. The modification by magnetite decreases the size of the pores to 50–100 nm in bentonite and increases the Seebeck coefficient by 30% on average. The incorporation of phosphate ions causes the decrease of the thermoelectric effect under rising the temperature. Design by PO43– increases the pore sizes more than two times and drops the Seebeck coefficient by 70% on average.
27
Sosnowska, Agnieszka, Tomasz Grabowski y Andrzej Harasimiuk. "Przyrodnicze i antropogeniczne uwarunkowania funkcjonowania krajobrazu równiny łowicko-błońskiej na przykładzie fragmentu Gongolina-Pawłowice". Prace i Studia Geograficzne 66, n.º 3 (31 de diciembre de 2021): 47–62. http://dx.doi.org/10.48128/pisg/2021-66.3-04.
Texto completoResumen
The Łowicz-Błonie Plain is a flat and monotonous part of the late-glacial landscape. The parent material is dominated by loam, silt and clay covered with sand of various thickness. The main aim of the study was to indicate the natural and anthropogenic determinants of the fertile plain landscape’s functions, which has been intensively used for agriculture. Natural environmental conditions are determined by the vicinity of contrasting in humidity and trophism areas. The current state of the natural environment is the result of both the natural basis and anthropogenic transformations. The biggest changes in expanding the possibilities of using the trophic potential are related to artificial water drainage system.
28
La Noce, Michele, Alessandro Lo Faro y Gaetano Sciuto. "Clay-Based Products Sustainable Development: Some Applications". Sustainability 13, n.º 3 (28 de enero de 2021): 1364. http://dx.doi.org/10.3390/su13031364.
Texto completoResumen
Clay has a low environmental impact and can develop into many different products. The research presents two different case studies. In the first, the clay is the binder of raw earth doughs in order to produce clay-bricks. We investigate the effects of natural fibrous reinforcements (rice straws and basalt fibers) in four different mixtures. From the comparison with a mix without reinforcements, it is possible to affirm that the 0.40% of basalt fibers reduce the shrinkage by about 25% and increase the compressive strength by about 30%. Future studies will focus on identifying the fibrous effects on tensile strength and elastic modulus, as well as the optimal percentage of fibers. In the second study, the clay, in form of brick powder (“cocciopesto”), gives high alkaline resistance and breathability performance, as well as rendering and color to the plaster. The latter does not have artificial additives. The plaster respects the cultural instance of the original building. The research underlines how the use of a local (and traditional) material such as clay can be a promoter of sustainability in the contemporary building sector. Future studies must investigate further possible uses of clay as well as a proper regulatory framework.
29
Ehret, David L., Carol Koch, Jim Menzies, Peter Sholberg y Tim Garland. "Foliar Sprays of Clay Reduce the Severity of Powdery Mildew on Long English Cucumber and Wine Grapes". HortScience 36, n.º 5 (agosto de 2001): 934–36. http://dx.doi.org/10.21273/hortsci.36.5.934.
Texto completoResumen
Foliar sprays of a nonswelling chlorite mica clay were applied to leaves of greenhouse-grown long English cucumber (Cucumis sativus L.) plants, either before or after an artificial inoculation with powdery mildew [Sphaerotheca fuliginea (Schlech.:Fr.) Poll.] and to field-grown wine grapes (Vitis vinifera L.) before natural inoculation with powdery mildew [Uncinula necator (Schwein.) Burrill]. In all cases, the clay sprays did not eradicate the pathogen, but resulted in significant reductions in disease severity. In cucumber, a single spray of 0.5% clay reduced colony numbers on leaves by up to 60%. Spraying after inoculation was generally more effective than spraying before inoculation. In grapes, repeated sprays of either 2% or 4% clay were applied through the season to `Reisling' and `Chancellor' vines. Four percent clay reduced the amount of leaf surface covered by mildew by 22% in `Reisling' and 51% in `Chancellor'. Both concentrations reduced the incidence of mildew on clusters and canes. No treatment effects were observed on fruit quality. Our results demonstrate that foliar sprays of clay can reduce the severity of Sphaerotheca fuliginea and Uncinula necator on cucumbers and grapes, respectively.
30
Hamisi, Risper Ann, Charles M. Warui y Peter Njoroge. "Nesting success of Sharpe’s Longclaw (Macronyx sharpei Jackson, 1904) around the grasslands of lake Ol’bolossat Nyandarua, Kenya". Journal of Threatened Taxa 14, n.º 1 (26 de enero de 2022): 20461–68. http://dx.doi.org/10.11609/jott.6762.14.1.20461-20468.
Texto completoResumen
Sharpe’s Longclaw Macronyx sharpei is an endangered Kenyan endemic bird restricted to high-altitude grasslands with long tussocks. The species occurs on the grasslands surrounding Lake Ol’Bolossat in Nyandarua, Kenya, an area that is globally recognized as an Important Bird and Biodiversity Area. The grasslands receive little conservation measures, which have led to the decline in the population density of Sharpe’s Longclaw. Nesting success in birds is crucial for their population growth. The daily survival rate for natural nests of Sharpe’s Longclaw in the grasslands of Lake Ol’Bolossat had not been systematically assessed prior to this study. Natural nests were actively searched during the breeding seasons of March–May 2016, while artificial nests were constructed using dry grass containing artificial eggs made of cream modeling clay. Natural nests had a higher daily nest survival percentage than artificial nests. The highest daily nest survival rate was 40% and the lowest 0.01%. Predators, livestock grazing and fires greatly reduced the survival of nestlings. We recommend intensive ecological management of the high-altitude grasslands of Lake Ol’Bolossat.
31
Dubovceva, EkaterinaNikolaevna Nikolaevna. "THE USE OF OCHRE IN CERAMIC PRODUCTION IN THE NORTH OF WESTERN SIBERIA". Samara Journal of Science 4, n.º 4 (1 de diciembre de 2015): 37–47. http://dx.doi.org/10.17816/snv20154204.
Texto completoResumen
A lot of evidence to the use of ochre in the manufacture of neolithic, eneolithic ceramics of the Urals and Western siberia are accumulated. the article discusses the cases of red ochre use as an inclusion in the clay and paints for ceramics. the main problem was to learn to distinguish between accidental and intentional use of ochre in ancient times. this problem was solved through a series of experiments. the focus of the study was the means of obtaining the ochre from limonite, methods of staining pottery and modeling of ochre as an inclusion in the texture. Besides, clay from various sources from the territory of Western siberia was investigated in order to determine the presence of limonite, which is ochre in its natural state. this allowed to identify archaeological sites where existed the tradition of using ochre for the manufacture and decoration of pottery. Based on the analysis of 35 samples of clay from russia and the results of experiments were identified criteria for distinguishing natural and artificial ocher impurities in the texture. as a result of technological analysis of ceramics from 50 archaeological sites north of Western siberia, it was found that there was a tradition use of ocher as inclusion in clay. it could be incorporated into the texture in the form of crushed fired limonite or hematite and dried red clay in the neolithic. these recipes are not mass, so the question about the function of ocher in the clay is very interesting, but this is a task for future research.
32
Pivinskii, Yu E., V. A. Doroganov y E. A. Doroganov. "Cement-Free Refractory Concretes. Part 6. Comparative Evaluation of Natural (Clay) and Artificial Ceramic Binders (HCBS)". Refractories and Industrial Ceramics 61, n.º 5 (enero de 2021): 507–12. http://dx.doi.org/10.1007/s11148-021-00512-9.
Texto completo
33
Vinsot, Agnès, C. Anthony J. Appelo, Mélanie Lundy, Stefan Wechner, Cristelle Cailteau-Fischbach, Philippe de Donato, Jacques Pironon, Yanick Lettry, Catherine Lerouge y Pierre De Cannière. "Natural gas extraction and artificial gas injection experiments in Opalinus Clay, Mont Terri rock laboratory (Switzerland)". Swiss Journal of Geosciences 110, n.º 1 (23 de febrero de 2017): 375–90. http://dx.doi.org/10.1007/s00015-016-0244-1.
Texto completo
34
Lin, Bin, Yongjia Zhao y Guoqiang Li. "Analysis of Damage Constitutive Model for Frozen Red Clay under Uniaxial Compression". Advances in Materials Science and Engineering 2022 (13 de octubre de 2022): 1–11. http://dx.doi.org/10.1155/2022/8001246.
Texto completoResumen
At present, it is in the peak period of infrastructure construction in western China, and due to the natural climate, the soil has been frozen for a long time, but there is little research on frozen red clay at present. Therefore, it is necessary to further study the mechanical properties of frozen red clay. In this paper, taking the remolded red clay as the test material, the change characteristics of uniaxial compression and uniaxial creep of frozen soil under different test factors are studied by artificial freezing method, and the damage theory is introduced to analyze the test results. The results of uniaxial compression test of frozen soil show that temperature has a great influence on the uniaxial compressive strength, and the compressive strength increases with the decrease of temperature, and the damage theory is introduced. It is found that the initial damage stress increases with the decrease of temperature, while the initial strain changes little with temperature. A damage constitutive equation which can well reflect the whole damage process of frozen red clay is established. The experimental research results of this paper can provide some theoretical reference for the engineering of soil quality for freezing red clay.
35
Solonenko, L. I., K. I. Uzlov, T. V. Kimstach, Ya V. Mianovska y D. Yu Yakymenko. "Influence of ice structure on vitability of frozen sand-water and sand-clay mixtures". Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, n.º 1 (29 de febrero de 2024): 32–40. http://dx.doi.org/10.33271/nvngu/2024-1/032.
Texto completoResumen
Purpose. To establish influence regularity of sand, water and clay preparation conditions on vitability of frozen mixtures made from combinations of these components and to increase the castings quality in foundries, as well as to improve technologies for artificial freezing of soils for underground constructions. Methodology. In this research, sand, clay, and water are used. Ice quality is estimated visually after water freezing at -15 °C in glass tubes. Frozen mixtures’ vitability at -15 °C is studied on beam-type samples. As indicators of survivability, the time to 1 mm bending of samples on supports and the time to their destruction are accepted. The time is recorded with a stopwatch, the temperature with an alcohol thermometer, the mass with electronic scales and the deflection arrow with a clock-type indicator. Findings. The presence and amount of water-soluble impurities in rare water significantly influence the nature, size and distribution of gas bubbles in ice, as well as frozen sand-water mixtures vitability. Frozen mixtures’ survivability increases with water content in them increasing, and, for sand water mixtures, survivability is maximum if ice has a homogeneous structure. Among mixtures with clays, the mixture with non-swollen kaolin clay has the greatest vitability. Regarding survivability, recommendations for manufacturing products from frozen foundry mixtures have been developed. Originality. For the first time, deformation change kinetics (bending arrows) under the influence of beam-type samples’ self-mass from mixtures of quartz sand and water and quartz sand, clay and water frozen at -15 °C, which have been previously prepared in different ways, have been investigated. Insights into the influence of various factors and ice quality on the vitability of frozen mixtures have been further developed. Practical value. The obtained results can be useful for expanding ideas about natural frozen soils’ behavior during their cyclic temperature changes, soils artificially frozen during mine shafts elaboration, escalators’ and junctions’ tunnels, etc. when constructing subways. In foundries, the developed recommendations will reduce technological losses and will improve casting quality made using frozen casting molds and cores from sand-water or sand-clay-water mixtures, castings’ patterns and their pouring systems from sand-water mixtures.
36
Pendyurin, E. A., S. Yu Rybina, L. M. Smolenskaya y M. M. Latypova. "Research on Some Physicochemical Parameters of Artificially Created Soil Mixtures". Ecology and Industry of Russia 24, n.º 9 (1 de septiembre de 2020): 27–31. http://dx.doi.org/10.18412/1816-0395-2020-9-27-31.
Texto completoResumen
Compositions of artificial soil mixtures, including sand, clay, defecation mud, waste from wet magnetic separation and plant residues in different proportions have been developed. The components were preliminarily comminuted by an auger-drill in order to obtain a homogeneous composition with subsequent granulation, stored in natural conditions in the autumn-winter period, followed by filling in experimental vessels. No any phytotoxic effect for the initial components and for all analyzed samples of the obtained artificial soil mixtures was detected. The chemical composition and some physicochemical properties of artificial soil mixtures, such as density, deposit of moisture and humus content, were determined. It was shown that the samples of the obtained soil mixtures are close to the control (dark gray forest soil of the Belgorod region) and can be recommended for further use in creating cultural landscapes as a substitute for natural soil. The developed type of artificial soil mixtures is suitable for the cultivation of bulbous crops; moreover, a large increase in yield in comparison with the control for some compositions was found. Artificially created soil mixtures reduce the harmful effect on the environment by eliminating the storage of industrial waste such as iron ore and food, plant residues used in the composition of the artificial soil mixture. Artificial soil mixture can be used for remediation of technologically disrupted areas, which will allow restoring disturbed lands and reducing man-caused impact on solid waste landfills. The addition of industrial waste allows them to be re-involved in the technological cycle, which contributes to the development of low-waste and waste-free technologies. The results obtained indicate the possibility of using the studied soil mixtures for cultivation of the decorative bulbous plants. To recommend the developed compositions for the use in agriculture, it is necessary to assess the possibility of impurity translocation from soil samples into cultivated crops.
37
Grenier, Martine, Sovan Lek, Marco A. Rodríguez, Alain N. Rousseau y Stéphane Campeau. "Algae-based Biomonitoring: Predicting Diatom Reference Communities in Unpolluted Streams using Classification Trees, Random Forests, and Artificial Neural Networks". Water Quality Research Journal 45, n.º 4 (1 de noviembre de 2010): 413–25. http://dx.doi.org/10.2166/wqrj.2010.041.
Texto completoResumen
Abstract The Eastern Canadian Diatom Index (IDEC) was developed to evaluate the ecological integrity of streams along a pollution gradient, as a function of the dissimilarity between current diatom communities and suitable reference communities. Distinguishing natural variations in community structure from those induced by human activities is essential for proper assessment of dissimilarity. To account for the effect of the natural variation in pH on this assessment, two IDEC subindices were used: one for sites with diatom reference communities typical of naturally alkaline water pH, and another for sites with communities typical of naturally circumneutral water pH. This study used three statistical models, namely classification trees (CT), random forests (RF), and artificial neural networks (ANN) to: (i) identify the environmental variables discriminating between alkaline and neutral reference communities (“biotypes”), and (ii) compare their predictive capacities. Models identified clay rocks, gneiss/paragneiss rocks, siliceous rocks, and carbonated rocks as the main geological features discriminating reference biotypes. For the reference streams, clay, siliceous, and carbonated rocks were associated with high water pH while gneiss/paragneiss rocks were associated with low water pH. Both ANN and RF models behaved similarly across all performance criteria and yielded general models useful for identifying the appropriate IDEC sub-index.
38
Havryushenko, Oleksandr O., Oleksandr O. Mytsyk, Mykola M. Kharytonov, Natalia V. Honchar, Mykhailo G. Babenko, Valentyna T. Pashova y Yuriy I. Tkalich. "The suitability of physical and chemical properties of rocks for land reclamation in different subzones of the Ukrainian Steppe". Journal of Geology, Geography and Geoecology 31, n.º 2 (3 de agosto de 2022): 251–59. http://dx.doi.org/10.15421/112223.
Texto completoResumen
The study of the properties of disturbed soils and rocks makes it possible to establish the parameters of the natural fertility of the studied substrates, to detect limiting factors, and to determine a set of restoration measures. The tested overburden rocks with the largest stratigraphic share of the open-pit quarries of the Nikopol manganese and Kerch iron ore deposits were loamy-like loess (Quaternary) and grey-green clay (Neogene). There is a certain parametric relationship between texture, density, porosity, the structural and physical state of different models of artificial reclaimed profiles. The composition and properties of rocks of edaphic structures of technosoils differ according to zonal natural and climatic conditions of the subzones of the Ukrainian Steppe. Loess-like loam and grey-green clay of the Kerch iron ore deposit are distinguished by a higher bulk density, lower porosity, and wilting moisture compared to samples from the Nikopol manganese ore basin. The use of the rotor complex leads to mechanical destruction and an increase in the content of small particles of rocks. Self-compacting processes occur to a large extent in multilayer structures. This pattern is observed at the boundary of the backfill differentiated in texture layers of technosoils. This indicates the existence of a barrier that prevents the relationship of edaphic properties between substrata stratums. Optimal ratio of clay minerals provides a rather high capacity of grey-green clay for water absorption. The model of technosoil composed of grey-green clay differs in a larger number of water-resistant micro-aggregates. The best conditions for land reclamation are connected with including grey-green clay in two- and three-layer constructions of technosoils, providing a waterproofing effect.
39
Rayhani, M. HT, E. K. Yanful y A. Fakher. "Desiccation-induced cracking and its effect on the hydraulic conductivity of clayey soils from Iran". Canadian Geotechnical Journal 44, n.º 3 (1 de marzo de 2007): 276–83. http://dx.doi.org/10.1139/t06-125.
Texto completoResumen
Clay materials have many environmental applications, especially in situations where a hydraulic barrier is desired. However, as the plasticity of clay increases, cracks tend to develop during cycles of long dry spells. This is particularly a concern in the construction of covers or installation of landfill liners prior to waste filling. In the present study, specimens prepared from three natural clayey soils from Iran used for clay barrier construction, and one artificial clayey soil, were subjected to cycles of wetting and drying. Surface cracks of different dimensions formed as a result of drying. Specimens with the largest volumetric shrinkage strains typically contained the highest number of cracks. Specimens that developed cracks were subjected to hydraulic conductivity testing. The results showed that the dimension of cracks increased with increasing plasticity index and clay content and, so, the initial hydraulic conductivity increased with increasing plasticity index and cycles of drying and wetting. Cracking increased the hydraulic conductivity by 12–34 times, depending on the plasticity of the soil. After a long saturation time, the hydraulic conductivity of the soils decreased with an increase in saturation time, which could be associated with a self-healing process that affects the soils by different degrees.Key words: desiccation, cracking, plasticity, hydraulic conductivity, clay barriers, self-healing, volumetric shrinkage.
40
Ni, Jing, Gang-Lai Hao, Jia-Qi Chen, Lei Ma y Xue-Yu Geng. "The Optimisation Analysis of Sand-Clay Mixtures Stabilised with Xanthan Gum Biopolymers". Sustainability 13, n.º 7 (26 de marzo de 2021): 3732. http://dx.doi.org/10.3390/su13073732.
Texto completoResumen
Sand–clay mixtures can be encountered in both natural soils (e.g., residual soils, clay deposits and clinosols) and artificial fills. The method of utilising biopolymers in ground improvement for sand–clay mixtures has emerged recently. However, a full understanding of the strengthening effect of biopolymer-treated sand–clay mixtures has not yet been achieved due to a limited number of relevant studies. In this study, xanthan gum (XG), as one of the eco-friendly biopolymers, was used to treat reconstituted sand–clay mixtures that had various compositions in related to clay (or sand) content and clay type (kaolin and bentonite). A series of laboratory unconfined compression strength (UCS) tests were conducted to probe the performances of XG-treated sand–clay mixtures from two aspects, i.e., optimum treatment conditions (e.g., XG content and initial moisture content) to achieve the maximum strengthening effect and strengthening efficiency for the sand–clay mixtures with different compositions. The experimental results indicated that the optimum initial moisture content decreased as the sand content increased. The optimum XG content, which also decreased with the increasing sand content, remained approximately 3.75% for all sand–kaolin mixtures and 5.75% for all sand–bentonite mixtures if calculated based on clay fraction. While untreated sand–kaolin mixtures and sand–bentonite mixtures had comparable UCS values, XG-treated sand–kaolin mixtures seemed to have better improved mechanical strength due to higher ionic (or hydrogen) bonds with XG and low-swelling properties compared with bentonite. The deformation modulus of XG-treated sand–clay mixtures were positively related with UCS. The variation in UCS and stiffness for each treatment condition increased as the sand content was elevated for both sand-kaolin and sand-bentonite mixtures. An increment in the proportion of the heterogeneous composite formed by irregular sand particles conglomerated with the XG–clay matrix in total soil might be responsible for this phenomenon.
41
Maslikova, K. P. "Eсomorphic structure of the soil macrofauna communities of technosols of the Nikopol Manganese Ore Basin". Biosystems Diversity 26, n.º 2 (11 de abril de 2018): 85–91. http://dx.doi.org/10.15421/011813.
Texto completoResumen
This study established features of the animal population of artificial soil-like bodies – technosols in terms of ecomorphic analysis. The survey was conducted at the research station of the Dnipro State Agricultural University in the city Pokrov in 2012–2014. The experimental polygons were laid within four technosol types: pedozems, sod loess-like lithogenic soils on loam, grey-green clay and red-brown clay. The polygon consisted of 15 transects and each transect was composed of seven test sites. The distance between rows in the polygon was 3 m. Each test site was a square with size 3 × 3 m. The manual sorting of the soil-zoological samples was conducted within each site for areas 0.25 × 0.25 m to the depth where animals were found. Samples were taken in late April or early May. In general, for each period of counting for each polygon 105 soil-zoological samples were taken 123 species of invertebrates were found in the soil macrofauna community of the technosols. These communities are a steppe monoceonosis with a tendency to transformations into pseudoomonoceonosis on account of increased share of pratants. The soil macrofauna of sod lithogenic soils on grey-green clay and loam on loes-like clays is most adapted to xerophilous condition. Animal communities in pedozems and sod-lithogenic soils or on red-brown clay have a more mesophilic character. The trophoceonomorphic structure of the soil macrofauna community indicates a significant potential of the fertility of artificial soil. The aeromorphs’ structure reveals a significant ability of technosols to create cracks and pores, which can lead to hyperaeration. The dominant part of the of soil macrofauna community was hypercarbonatophils. Against the background of the steppe character, the soil macrofauna community had a topomorphic structure that is unusual for natural steppe black soil biogeocenoses on loess-like loam. The trophomorph structure was greatly dominated by phytophages, which indicates the prevalence of processes of mineralization of plant residues under the humification process. The phoromorphic spectrum of soil animal communities was dominated by ecological groups which move without the active construction of tunnels.
42
Koňáková, Dana y Eva Vejmelková. "Effect of Metashaleas SCM on Mechanical and Thermal Properties in Concrete Production". Applied Mechanics and Materials 763 (mayo de 2015): 41–46. http://dx.doi.org/10.4028/www.scientific.net/amm.763.41.
Texto completoResumen
This article is focused on SCM questions. Studied material - metashale belongs among artificial pozzolana with natural origin. Shale is clay mineral and by its burning at 700°C similar material as metakaolin arises. Metashale is used as cement replacement up to 60% in concrete production. By means of measurement of basic physical properties, mechanical strength and thermal characteristic the effect of metashale is determined. Concrete containing 20% of metashale shows improvement of studied properties except of thermal conductivity. The 40% of the SCM leads to concrete production with same properties as the reference concrete. And when 60% of the burnt clay is utilized, final values of studied properties shows little deteriorations. However all studied materials shows appropriate properties to be applicable in civil engineering branch as load-bearing concrete.
43
Rati Syafiana Putri y Desyandri. "JENIS TEKNIK DAN BAHAN BAHAN YANG DIGUNAKAN PADA KERAJINAN TANGAN SUMBER BELAJAR SENI BUDAYA DAN PRAKARYA DI SEKOLAH DASAR". Didaktik : Jurnal Ilmiah PGSD STKIP Subang 9, n.º 3 (31 de julio de 2023): 994–1006. http://dx.doi.org/10.36989/didaktik.v9i3.1572.
Texto completoResumen
The study aims at describing a variety of handicraft techniques and materials which exist in Sumatera Barat. This study employed qualitative descriptive approach. The subject of this study was handicraft home industry in Sumatera Barat. The data collection of this study obtained by conducting observation, documentation, and interviews. The results indicated that (1) home industry of handicraft in Sumatera Barat is feasible to be utilized as a learning resource in elementary school. In addition, the variety of technique of making handicrafts noted within this study are wickerworking, carving, sewing, tie, stringing-beading, application, embroidering, batik, folding, clay crafting, spinning, rotating, printing, screen printing, painting, scratching and lathing. (2) The variety of handicrafts materials selected or used is in the form of natural and artificial materials such as clay, katu, corn husk, cloth, plastic, and paper.
44
Blaise Ngwem Bayiha, Benjamin Bahel, Fabien Kenmogne, Ulrich Nota Yemetio, Emmanuel Yamb y Ndigui Billong. "Comparative study of the effects of a natural pozzolan and an artificial pozzolan on the hydraulic properties of Portland cement mortar". Global Journal of Engineering and Technology Advances 14, n.º 1 (30 de enero de 2023): 107–19. http://dx.doi.org/10.30574/gjeta.2023.14.1.0021.
Texto completoResumen
The comparative study of some effects of natural and artificial pozzolans on the hydraulic properties of Portland cement mortar is performed in this work. The natural pozzolan used coming from the Djoungo deposit, Moungo department in the Littoral region (Cameroon) was finely ground and then sieved at 100 μm. The artificial pozzolan used is the alluvial clay of Etoa collected from Yaoundé III District in Mfoundi Division of the Centre Region of Cameroon. It was thermally activated at 700°C after grinding and sieving. The chemical and mineralogical analysis of the raw materials were studied by X-ray fluorescence, infrared spectrometry (FTIR) and X-ray diffraction (XRD) then the specific surfaces and the absolute densities were determined. The formulation of the pastes and mortar was obtained by substituting Portland cement with different pozzolans at different percentages, while the initial and final setting time of the fresh pastes were determined. Linear shrinkage, water absorption, apparent density, flexural strength and compressive strength tests at 7 and 28 days were determined on the hardened mortars. The results obtained show an increasing in the initial and final setting time with the addition of the amount of pozzolan (natural or artificial), the pozzolans played the role of setting retarder in the mixtures, finer particles of the artificial pozzolan speed up the setting time of pastes as compared to that with natural pozzolan. The shrinkage of the hardened mortars increased with the addition of the pozzolans, but it was less than 0.2% in all the samples, the specimens with artificial pozzolans were more affected by the drying shrinkage. The mortars had good mechanical resistance but from 30 to 40% pozzolan, whether artificial or natural, the resistance dropped, the dilution phenomenon caused by the partial replacement of the cement was responsible for the drop in resistance with the addition of pozzolans. The water absorption rate and the apparent density of the specimens decrease when the percentage of pozzolan increases in the mortars. Artificial pozzolan offers a better water absorption rate compared to natural pozzolan due to its higher specific surface. Natural pozzolan makes it possible to obtain a denser mortar.
45
Risdanareni, Puput, Yury Villagran, Katrin Schollbach, Jianyun Wang y Nele De Belie. "Properties of Alkali Activated Lightweight Aggregate Generated from Sidoarjo Volcanic Mud (Lusi), Fly Ash, and Municipal Solid Waste Incineration Bottom Ash". Materials 13, n.º 11 (2 de junio de 2020): 2528. http://dx.doi.org/10.3390/ma13112528.
Texto completoResumen
Production of artificial lightweight aggregate (LWA) from industrial by-products or abundant volcanic mud is a promising solution to prevent damaging the environment due to the mining of natural aggregate. However, improvements are still needed in order to control the high water absorption of LWA and strength reduction in resulting concrete or mortar. Hence in this research, fly ash, municipal solid waste incineration bottom ash (MSWI BA), and Sidoarjo volcanic mud (Lusi) were employed as a precursor and activated using NaOH 6 M and Na2SiO3 in producing LWA. The influence of the type of the precursors on the physical properties of resulting LWA was investigated. The effect of replacing natural fine aggregate with the resulting LWA on the compressive strength and volume density of mortar was also determined. Finer particles, a high amount of amorphous phase, and low loss on ignition (LOI) of the raw material improved the properties of resulting LWA. Mortar compressive strength was decreased by 6% when replacing 16% by volume of natural fine aggregate with fly ash based LWA. Compared to the expanded clay LWA, the properties of alternative LWAs in this study were slightly, but not significantly, inferior. Alternative LWA becomes attractive when considering that expanded clay LWA requires more energy during the sintering process.
46
Selin, Dmitrii V. y Yuriy P. Chemyakin. "Features of Ceramics of the Kulai Culture (Surgut Variant) of the Barsov gorodok I/32 Site (Surgut-Ob Region)". Archaeology and Ethnography 20, n.º 5 (2021): 116–28. http://dx.doi.org/10.25205/1818-7919-2021-20-5-116-128.
Texto completoResumen
Purpose. Barsova Gora is a unique archaeological and landscape site located in the Tyumen Region of the Russian Federation. The archaeological site Barsov gorodok I/32 is located on the edge of the bank of Utoplaya river. A visual comparison of the ceramics of the early Iron Age from the Barsov gorodok I/31–32 sites and the ceramics of the Barsov gorodok I/4 site from the east showed their great similarity, if not their identical nature. For a correct comparison and identification of similarities and differences in the ceramics of these sites, it is necessary to conduct a comprehensive study of the products of each settlement using a unified technique. The study is devoted to the analysis of ceramics of the Barsov gorodok I/32 site. Results. The most common motifs are rows of ‘ducks’. Other common patterns are: short wavy horizontal and vertical prints (‘birds’ and ‘snakes’), rows of stamp prints, notches and ‘pearls’. There are no non-ornamented dividing zones on the vessels. There are no ornaments in the form of a series of hemotheric figures and meanders. The upper edges of the vessels are flat (28 %) or beveled inward (72%). In 33% of cases, a cornice is present. The ceramics are made from low-sand ferruginous clays with a natural admixture of sand, mica, brown iron ore, and scraps of vegetation. Artificial impurities are represented by chamotte, broken stone and organic matter. Four recipes of clay paste have been revealed: clay + broken stone; clay + broken stone + chamotte; clay + chamotte; clay + chamotte + organic matter. The ceramics are made with ribbons. The shape of the vessels is cauldron-like. Conclusion. The absence of non-ornamented dividing zones, the presence of rows of short wavy horizontal and vertical impressions (‘birds’ and ‘snakes’), the presence of inwardly beveled upper edges of the vessels with ornamented cornices testify to the late existence of this pottery. The ceramics of the Barsov gorodok I/32 site can be attributed to the late stage of the Kulai culture (Surgut variant).
47
Corinaldesi, Valeria. "Influence of Lightweight Aggregates and GRP By-Product Powders on the Properties of Self-Compacting Concretes". Advanced Materials Research 548 (julio de 2012): 215–20. http://dx.doi.org/10.4028/www.scientific.net/amr.548.215.
Texto completoResumen
Self-compacting lightweight concrete was developed to attain good workability, high compressive strength (at least 50 MPa), minimum cracks, and low specific weight (less than 2000 kg/m3), as well as low elastic modulus (about 30 GPa). The attention was also focused on sustainability of this construction material, which was improved by using in the mixture both GRP industrial by-product as filler and artificial (light expanded clay) or recycled (demolished concrete) as coarse aggregates replacing natural gravel. Satisfactory, if not excellent, results were obtained from the collected experimental data.
48
Syahyadi, Rizal, Nelly Safitri, Riza Widia, Safriadi y Azwar. "Building Integrated Photovoltaic (BIPV): Implementing Artificial Intelligent (AI) on Designing Rooftile Photovoltaic". International Journal of Data Science 4, n.º 1 (20 de mayo de 2023): 60–66. http://dx.doi.org/10.18517/ijods.4.1.60-66.2023.
Texto completoResumen
The monocrystalline photovoltaic (PV) is integrating into the natural clay used to fabric the terracotta rooftile. The enlargement of the rooftile's dimension increased the power output of the PVs. This paper describes briefly the technology of building integrated photovoltaic (BIPV) development and integration to buildings and houses, especially by using artificial intelligent (AI) while composing and designing the terracotta rooftile PV. The examination of property’s parameter namely dimensions of the terracotta rooftile PVs on top of the house, the voltage, current, power, and efficiency of the PVs themselves were also considered. As the examination run, we also compare the results to the convenient mounted rooftop PV. The results showed that the output power of the PV reached its maximum power as the dimension of the terracotta rooftile PVs enlarge to fully cover the roof.
49
Pluim, Babette M., Benjamin Clarsen y Evert Verhagen. "Injury rates in recreational tennis players do not differ between different playing surfaces". British Journal of Sports Medicine 52, n.º 9 (16 de febrero de 2017): 611–15. http://dx.doi.org/10.1136/bjsports-2016-097050.
Texto completoResumen
ObjectiveThe aim of this study was to determine whether there is a difference in the prevalence of tennis injuries between the four most common court surfaces in the Netherlands, including hard court, clay, sand-fill artificial grass and red-sand-fill artificial grass. Natural grass was not included in this study.MethodsThis was a repeated cross-sectional study over 6 months, involving members of the Royal Netherlands Lawn Tennis Association (KNLTB). A monthly questionnaire was sent to a random sample of 20 000 KNLTB members, stratified by their club’s playing surface. The questionnaire included questions on court surface, tennis exposure and physical complaints, using the Oslo Sports Trauma Research Centre questionnaire on health problems.ResultsA total of 3656 (18%) of the 20 000 invited members completed at least one of the monthly questionnaires [mean age 49 years (15)]. A total of 4047 injuries were reported by 1957 respondents. Of these injuries, 3246 (80%) were overuse and 801 (20%) were acute. There were no statistically significant differences in injury prevalence between groups who played primarily on any one of the four court surfaces. However, players who played on multiple surfaces had a higher injury prevalence, particularly of overuse injuries, than those who primarily played on one court surface. Compared with the other court surfaces, there was a higher prevalence of lower limb overuse injuries when playing on hard court.ConclusionThere is no significant difference in the overall prevalence of injury on clay, hard court, sand-fill artificial grass and red-sand-fill artificial grass.
50
Winsley, J. Bright Brabin y M. Muthukannan. "Behaviour of Expanded Flyash Clay Aggregate Concrete Exposed to Elevated Temperature". International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems 29, Supp01 (26 de marzo de 2021): 181–91. http://dx.doi.org/10.1142/s0218488521400109.
Texto completoResumen
Expanded flyash clay aggregate (EFCA) is a promising sustainable alternative to coarse aggregate in concrete. Concrete specimens with conventional natural aggregate and EFCA as coarse aggregates were prepared separately and exposed to elevated temperatures of range 200°C, 400°C, 600°C and 800°C, observed for surface changes like change in color and formation of visual cracks, tested for loss in mass, strength and water absorption, analyzed by XRD for mineralogical changes through variation in chemical composition. Specimens when exposed up to 400°C has not shown any notable changes in the above property, beyond which strength of both specimens started to decrease gradually, at higher temperature EFCA mix showed loss in mass of 4.5% compared with normal concrete, visual observation of specimen surface showed EFCA specimens sustained cracks till 600°C. EFCA mix also showed a constant rate of water absorption. Concrete with EFCA showed consistently higher compressive strength at higher temperature up to 400°C and found satisfactory in all aspects tested made EFCA as coarse aggregate in concrete as a sustainable alternative to natural aggregates.