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Huang, Yue, Jasper F. Kok, Raleigh L. Martin, Nitzan Swet, Itzhak Katra, Thomas E. Gill, Richard L. Reynolds i Livia S. Freire. "Fine dust emissions from active sands at coastal Oceano Dunes, California". Atmospheric Chemistry and Physics 19, nr 5 (7.03.2019): 2947–64. http://dx.doi.org/10.5194/acp-19-2947-2019.
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Abstract. Sand dunes and other active sands generally have a low content of fine grains and, therefore, are not considered to be major dust sources in current climate models. However, recent remote sensing studies have indicated that a surprisingly large fraction of dust storms are generated from regions covered by sand dunes, leading these studies to propose that sand dunes might be globally relevant sources of dust. To help understand dust emissions from sand dunes and other active sands, we present in situ field measurements of dust emission under natural saltation from a coastal sand sheet at Oceano Dunes in California. We find that saltation drives dust emissions from this setting that are on the low end of the range in emissions produced by non-sandy soils for similar wind speed. Laboratory analyses of sand samples suggest that these emissions are produced by aeolian abrasion of feldspars and removal of clay-mineral coatings on sand grain surfaces. We further find that this emitted dust is substantially finer than dust emitted from non-sandy soils, which could enhance its downwind impacts on human health, the hydrological cycle, and climate.
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Chmiel, Stanisław, Stanisław Hałas, Sławomir Głowacki, Joanna Sposób, Ewa Maciejewska i Andrzej Trembaczowski. "Concentration of soil CO2 as an indicator of the decalcification rate after liming treatment". International Agrophysics 30, nr 2 (1.04.2016): 143–50. http://dx.doi.org/10.1515/intag-2015-0085.
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Abstract This paper presents the results of investigation of decalcification of acid sandy and loamy sand soils by infiltration waters, and potential Ca-leaching after liming treatment. For this purpose, monthly measurements were made of the concentration of CO2 in the soil air, dissolved inorganic carbon in the soil waters, and their ionic composition. The determined dissolved inorganic carbon ranged from 5.9 to 10.6 mg dm−3 and from 9.9 to 16.5 mg dm−3 for the sandy and loamy sand soil, respectively. The Ca concentration in soil waters was determined as 5.9-12.4 mg dm−3 in sandy soil and 14.2-19.8 mg dm−3 in soil loamy sand. The calculated rate of decalcification amounted to 23.0 kg ha−1 year−1 in soil sandy and 19.4 kg ha−1 year−1 in loamy sand soil. The potential Ca-leaching is predicted as 124 kg ha−1 year−1 for S and 87 kg ha−1 year−1 for loamy sand soil. At the treatment level of 3 000 kg ha−1 4 year−1 of CaO, ~20% of the Ca-fertilizer can be leached after the liming treatment. The results of the CO2 concentration in the soil air may be useful in estimation of Ca-leaching from soils developed by slightly clayey sands and clayey sands in zones with a moderate climate.
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MUZAFFAROVA, Mauzhuda. "DILATATION OF THE METHOD OF THE FIXATION OF MOVEABLE SANDS". Transport Problems 17, nr 4 (1.12.2022): 79–89. http://dx.doi.org/10.20858/tp.2022.17.4.07.
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A new method of physicochemical blocking deflation of movable sands has been developed that represents their fixation in a wet state with binders. It is proposed to carry out sand-fixing works during rainy periods or after preliminary moistening of the sandy surface in order to intensify and reduce the cost of sand-fixing works. The substantiation is carried out on the example of some of the approved and recommended binders based on the express method of studying the possibility of their application to obtain a polymer sandy protective crust on wet sand. The emerging defensive hull is characterized by resistance to wind-sand stream and evaluated by plastic quality and thickness. The impregnation of damp sand with a smaller sum of cover than dry sand is related to an alteration within the nature of impregnation from gravity to capillary. With a decrease in the specific surface of the bulk material and an increase in the pore space, gravitational forces are predominant. The process of wet sand impregnation is associated with the acceleration of the adsorption of the dispersed phase and a reduction in the hole covered due to the partial occupation of the interpore space with water. As a result, in wet sand, the depth of sand impregnation with the binder increases at a lower consumption per unit volume of sand. The following has been established: the possibility of impregnation of approved and recommended binders into wet sand, the inverse dependence of the binder concentration in emulsion forms on the humidity of the sandy surface, the time of application of various binders after moistening the sand and the possible savings of binders.
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Xia, Yu Bo, Yue Suo Yang i Xin Qiang Du. "The Characteristic of Petroleum Contaminant Adsorption Materials and the Estimation of Adsorption Attenuation". Advanced Materials Research 179-180 (styczeń 2011): 197–202. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.197.
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Based on the experiment in lab and the investigation in study site, we have studied the adsorption of fine sand, medium sand and coarse sand which composes the aquifer. The different type's soil is different to the petroleum adsorption, the adsorptive capacity of fine sand is strongest, the coarse sand adsorption is worst. The adsorptive capacity of Sandy in 33.8% to 46.1%, adsorptive capacity of gravel is 9.2%. Freundlich model is more accurate to explain the sorption of the sands. The adsorption reaction of sand is very rapid, and it often only needs less than a day to reach adsorption reaction balance. The pollution levels are underestimated, and has been underestimated approximately 37.1% to 41.4%, and adsorption attenuation is a main action in study site.
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Ma'shum, M., JM Oades i ME Tate. "The use of dispersible clays to reduce water repellency of sandy soils". Soil Research 27, nr 4 (1989): 797. http://dx.doi.org/10.1071/sr9890797.
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Water-repellency in sandy soils is determined by the amount of hydrophobic organic matter coating the sand particles and the specific surface area of the sands. The hydrophobic state can be simulated by coating hydrophilic sand with cetyl alcohol. Admixture of finely particulate materials with either naturally occurring water-repellent sands or the model cetyl alcohol-coated sand markedly reduced the water-repellency. Dispersible sodic clays were more effective than calcium saturated clays in reducing water-repellency, suggesting that the addition of dispersible, fine-grained illites and kaolinites couid play an important role in the rapid control of water-repellent soils in field situations.
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Marion, D., A. Nur, H. Yin i D. Han. "Compressional velocity and porosity in sand‐clay mixtures". GEOPHYSICS 57, nr 4 (kwiecień 1992): 554–63. http://dx.doi.org/10.1190/1.1443269.
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Laboratory measurements of porosity and compressional velocity were conducted on unconsolidated brine saturated clean Ottawa sand, pure kaolinite, and their mixtures at various confining pressures. A peak in P velocity versus clay content in unconsolidated sand‐clay mixtures at 40 percent clay by weight was found. The peak in velocity is 20–30 percent higher than for either pure clay or clean sand. A minimum in porosity versus clay content at 20–40 percent clay by weight is also observed. Such behavior is explained using a micro‐geometrical model for mixtures of sand and clay in which two classes of sediments are considered: (1) sands and shaley sands, in which clay is dispersed in the pore space of load bearing sand and thus reduces porosity and increases the elastic moduli of the pore‐filling material and (2) shales and sandy shales, in which sand grains are dispersed in a clay matrix. For these sediments, the model reproduces the extrema in velocity and porosity and accounts for much of the scatter in the velocity‐porosity relationship.
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Miranda, Marck Douglas Miranda, Érica Miranda Caetano, Fabiane Leocádia da Silva, Francielle Câmara Nogueira i Carlos Alberto Pereira. "Analysis of the mechanical behavior of an alternative sand for foundry molding". Concilium 24, nr 3 (22.02.2024): 50–62. http://dx.doi.org/10.53660/clm-2809-24c24.
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The exploration and beneficiation of iron ore result in a substantial generation of waste, predominantly directed towards tailings dams, heightening environmental concerns. Faced with this environmental challenge, numerous studies have been devoted to seeking sustainable solutions, aiming at the utilization of waste in various sectors of the economy. In this context, this study focuses on the technical feasibility investigation of using sandy iron ore waste as molding sand in foundry processes. Foundry molding sand, crucial in casting, must meet specific requirements and exhibit particular characteristics to effectively fulfill its function. To address this issue, test specimens were fabricated using three distinct types of sands: Standard Sand, Sand 01 (without magnetic separation), and Sand 02 (subjected to magnetic separation), combined with two binders (bentonite and sodium silicate). Subsequently, the test specimens underwent mechanical tests for tension, flexure, and compression, with the aim of evaluating their ability to withstand applied forces. The results of these tests revealed that Sand 02, when combined with sodium silicate, demonstrated satisfactory performance, in accordance with established standards and studies for obtaining sands intended for molding in foundry processes.
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Liu, Jin, Zezhuo Song, Yuxia Bai, Zhihao Chen, Jihong Wei, Ying Wang i Wei Qian. "Laboratory Tests on Effectiveness of Environment-Friendly Organic Polymer on Physical Properties of Sand". International Journal of Polymer Science 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/5865247.
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The poor water stability, high penetrability, and low antierosion of sand affect the stability of the sandy soil slope. To understand the effectiveness of environment-friendly organic polymer on these physical properties of sand, a series of laboratory tests including water stability test, penetration test, and runoff erosion test of polymer reinforced sand were performed. The results of tests indicated that the organic polymers have obvious effects on the reinforced sand. The water stability of polymer reinforced sand had been improved strongly. All the reinforced sands with polymer ≥0.3% remained a stable structure at immersing time of 24 hours. The penetrability of the reinforced sand decreased with the increase of the polymer. The reinforced sand with polymer ≥7% was impermeable. The erosion resistance of sand increased with the increase of polymer content. With the polymer ≥4%, the sand surface kept intact with the scouring time more than 2 hours. The results could be applied as the reference for organic polymer reinforced sand engineering, especially for surface protection of embankment, slope, and landfill.
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Syvyj, M., i B. Gavrychok. "Construction sands of Podillya: patterns of distribution, resources and use". Journal of Geology, Geography and Geoecology 27, nr 3 (8.01.2019): 510–19. http://dx.doi.org/10.15421/111875.
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This article presents the characteristics of the resource base of building sands within the three Podillya regions, the patterns of sands distribution, and proposals for increasing the extraction of raw materials . The construction sands of Podillya are confined to the Upper Cretaceous, Neogene and Anthropogenicdeposits. The decrease of the thickness of the sandy strata of the Opilsk Neogene suite in the eastern direction was observed with the simultaneous increase in the thickness of the overlapping strata of the rocks. There is no apparent correlation between the thickness of sandy interlayers and the quality of sands. The interdependence of the chemical composition of Neogene sands and the sand size module is established.The genetic predisposition for the distribution of building sands in different parts of the Podillya territory has been established. Four groups of sand deposits of different age have been identified within the Podillya regions, which contrast sharply with single deposits in the neighbouring territories.There is a very uneven distribution of explored reserves of sandy raw materials across the region and accordingly in the provision of construction sands in the different oblasts /regions of Podillya. The areas best provided with sandy raw materials are the central districts of Ternopil region and Slavutsky district of Khmelnytsky region . Sands of the Baltic stage distributed in Vinnytsia region are mostly poor in quality, clogged with clay material and require enrichment. The further development of the mineral raw material base and the prospects for increasing the production of construction sand in the Podillya regions is associated with the increase in production at the prepared deposits, the commissioning of reserve deposits, the conducting of prospecting and exploration work in the proposed potentially exploitable areas and additional exploration of individual deposits that are exploited. The research allows us to evaluate objectively the existing base of sand raw materials for various purposes in the Podillya region and to develop on this basis measures to increase it. The importance of the study is determined by the acute shortage of the raw material in most administrative districts of Khmelnytsky and Vinnytsia regions, by the growth in the volume of construction work (and accordingly the requirements for sandy raw materials) both in Podillya and in the country.
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Soluk, Daniel A., i Hugh F. Clifford. "Microhabitat shifts and substrate selection by the psammophilous predator Pseudiron centralis McDunnough (Ephemeroptera: Heptageniidae)". Canadian Journal of Zoology 63, nr 7 (1.07.1985): 1539–43. http://dx.doi.org/10.1139/z85-228.
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The predaceous mayfly Pseudiron centralis McDunnough exhibited shifts in its association with different types of sandy substrate during larval development: stage I larvae were associated with marginal sands; stage II larvae exhibited no association; and stage III and IV larvae were associated with the substrate of the main-stream channel of the river, where sand is formed into active dunes (shifting sand). Ability to occupy areas of shifting sand is size related, probably because small larvae cannot cope with the physical stresses of these areas. Experiments indicate that stage III larvae avoid gravel, but do not differentiate between sand and silt. Shifting sands are hypothesized to be favourable environments for larger larvae because of greater accessibility of chironomid prey or the absence of potential predators in these areas. Larval spacing behavior is unlikely to affect patterns of larval distribution or density on the riverbed.
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Ćuk, Mirjana, Radenko Ponjarac, Dušan Igić, Miloš Ilić, Marius Oldja, Dragana Vukov i Andraž Čarni. "Historical overview of the Deliblato sands afforestation". Šumarski list 147, nr 7-8 (31.08.2023): 383–92. http://dx.doi.org/10.31298/sl.147.7-8.7.
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Deliblato Sands is one of the largest sandy areas in Europe. Given that developing of vegetation on the sand is a slow process, followed by human activities that devastate the plant cover (grazing, deforestation), the free-moving sand on Deliblato Sands exited until the 18th century. Unbound sand hindered the development of agriculture in the entire southern Banat region, so it was necessary to start a more intensive process of restraining sand masses. The afforestation of this area began in 1818 and is still ongoing. In the process of afforestation, nine periods can be recognized that differ in relation to afforestation/reforestation techniques, the choice of species or the organizational structure of the forestry units (and countries) of the area of Deliblato Sands belonged throughout history.The most significant results in the binding of free moving sand were achieved by the application of black locust (Robinia pseudoacacia L.) seedlings with juniper scrub (Juniperus communis L.) laid down on open sandy areas and sowing different species of grass between the rows of seedlings. This technique has been applied since the IV afforestation period (1878-1898). The largest areas were afforested in the V period (1898-1918), when parts of Deliblato Sands were formally protected for the first time in history as areas of importance for the preservation of biodiversity. The species most used in afforestation are black locust (Robinia pseudoacacia L.), Scots pine and black pine (Pinus sylvestris L., Pinus nigra J. F. Arnold), poplars (Populus sp.), and some shrubby (e.g. Juniperus virginiana L.) and herbaceous species (e. g. Ammophilla arenaria (L.) Link, Festuca vaginata Willd., Leymus arenarius (L.) Hochst., Carex arenaria L.). Today, Robinia pseudoacacia L. is most common tree species on Deliblato Sands and it occupies almost a third of the entire area.
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Rogerson, Andrew, Fiona Hannah, Gwen Hauer i Phillip Cowie. "Numbers of naked amoebae inhabiting the intertidal zone of two geographically separate sandy beaches". Journal of the Marine Biological Association of the United Kingdom 80, nr 4 (sierpień 2000): 731–32. http://dx.doi.org/10.1017/s0025315400002563.
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Numbers of naked amoebae (Gymnamoebae) inhabiting the lower intertidal zone of two sandy beaches were estimated using a novel enrichment cultivation method. Samples were collected between June and September, 1999. Beach sand at Kames Bay, Isle of Cumbrae, Scotland contained on average 2604 amoebae cm−3 while at Dania Beach, Florida, USA, sand harboured 4236 amoebae cm−3. This is the first study to focus on the abundance of naked amoebae inhabiting a sandy beach. These numbers are higher than densities generally reported for shallow subtidal sands and show that amoebae must be considered in future studies on the dynamics of sandy beach communities.
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Franco, CMM, ME Tate i JM Oades. "Studies on non-wetting sands .1. The role of intrinsic particulate organic-matter in the development of water-repellency in non-wetting sands". Soil Research 33, nr 2 (1995): 253. http://dx.doi.org/10.1071/sr9950253.
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The bulk of the organic matter in sands from the south-east of South Australia is present as discrete particles which constitute 4-6% of the mass of the sand. Hydrophobic particulate organic matter was separated from non-wetting sand obtained from two sites in the south-east of South Australia and characterized with respect to size and ability to induce water-repellency. When heated with both a wettable acid washed sand and a natural sand (non-wetting sand washed free of particulate organic matter), the intrinsic particulate organic matter induced strong water-repellence. The degree of hydrophobicity created was higher with the natural-washed sand than the acid-washed sand which indicated that a precoated surface, even one with a low initial hydrophobicity, has a strong enhancing effect. Particulate organic matter, especially the larger size fractions, acted as a reservoir of waxes or hydrophobic materials which diffused onto the surfaces of sand grains during heating, and particularly during wetting/heating/drying cycles. Thus, intrinsic particulate organic matter plays a substantial role in the development of water-repellency in sandy soils. In addition to hydrophobic waxes which diffuse out under environmental conditions prevalent in the field, water-repellency increases significantly when these hydrophobic particles interact with the natural precoated hydrophobic surface of the sand.
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H. O., Nwankwoala. "Geotechnical Investigation for Foundation Design at the West Bank of Light House Creek, Lagos Deep Offshore Logistics Free Zone, Nigeria". Engineering Management Research 8, nr 1 (7.05.2019): 31. http://dx.doi.org/10.5539/emr.v8n1p31.
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This study is aimed at investigation for foundation designs at the West Bank Creek, Lagos deep offshore. All field tests were conducted in accordance with standard geotechnical procedure. The soil profiles obtained within the depth explored at the site consist essentially of two soil zones. They are very soft silty clays and medium dense sands. Results revealed that within the depths bored, a relatively high deposit of clay overlies the boreholes from the river-bed to average depth of 3.0 m. In BHs 8, 10, 11 and 12, the clay extends beyond 3.0m thickness with varying depths ranging from 5.0 m to 8.0 m. However, prevalent deposits of sand underlie the clay to the end of the boreholes. In BHs 6 and 9, the entire holes are characterized by huge deposits of sand formation. Notably, the sandy formation exhibited appreciable Standard Penetration Test (SPT) blows indicating sands of medium densification. Based on the field investigations and comprehensive studies, the estimated volume of available sand fill material is 691,863 m3. Sand volume estimate was limited to -10.50 m from the river-bed. All the boreholes have potentials for sand borrows. Scooping of the clayey materials is required to expose the sand deposits. Dredging operation with appropriate dredger should be limited to the area covered by the survey.
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Ulyanov, V. Y. "Morphological Evaluation Results of Some Features of Alluvial Sands in the City of Dnipro". Science and Transport Progress, nr 6(96) (16.12.2021): 95–104. http://dx.doi.org/10.15802/stp2021/256577.
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Purpose. The research is aimed to obtain some missing data on the morphology of river sands within the city, in particular, reliable quantitative indicators that can be used in the calculation of soil bases. Methodology. According to the experimental-analytical method, a complex soil morphology was used, which takes into account the shape and nature of the grain surface in the entire sand volume studied. Morphological assessment was carried out not only for individual sand particles, but also for the entire volume of the soil studied, due to this an important factor in the formation of the shape and nature of the sand grain surface is the mineral composition of sand. For the most of the studied sands, quartz was the predominant mineral. In further studies, it is planned to study the Dnipro River sands of deeper horizons, which would make it possible to obtain data on the formation of contacts between sand grains, which can be lamellar or other shapes. Findings. This paper presents the results of determining morphological indicator, as well as studying the shape and nature of the surface of alluvial sand grains of the 1st floodplain terrace of the Dnieper River valley in the area of Monastyrskyi Island in the central part of the city. The results of similar works on the study of a number of genetic types of Quaternary sands of various genesis in the Dnieper River valley were also analyzed. Due to this analysis, data were obtained on the morphology of monomineral oligomictic alluvial sands, the shape and nature of the alluvium sand grains surface. Originality. For the first time for the central region of the city, some basic morphological characteristics of river Quaternary sands of the Dnieper River valley were obtained. It is also possible to note the tendency of decrease of morphology indicator in river sands of the Dnieper valley from sources to the mouth. Practical value. With all confidence, the results of the studies carried out can be implemented in the sandy soils of the foundations of buildings and structures of the city, as well as to artificial earthworks, in particular, alluvial massifs.
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Rhee, Seung Whee, i Woo Keun Lee. "Characteristics of Spent Foundry Sand - Loess Mixture as Ceramic Support Materials". Materials Science Forum 510-511 (marzec 2006): 378–81. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.378.
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Spent foundry sand (SFS) from cast iron industry mixed with loess was characterized to recycle spent foundry sand as ceramic support materials. Since SFS mostly consists of sand including binding agents and residue [1], it was used as permeable media, and loess, which has highly adsorptive and reactive properties, was used as support materials Leaching tests such as Korean Leaching Test (KLT) and TCLP (Toxicity Characteristics Leaching Procedure) showed that spent foundry sands from cast iron industry were not hazardous. Turbidity in furan sand was much higher than that in other sands, and turbidity was almost not changed with increasing amount of loess. The order of ORP (oxidation-reduction potential) in spent foundry sands was green sand > furan sand > CO2 sand. ORP was decreased with the amount of sand in furan sand and CO2 sand but was increased with the amount of sand in green sand. Hence, mixture of SFS and loess can be used as ceramic support materials with reductive or oxidative capability.
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Holtzer, M., D. Drożyński, A. Bobrowski i J. Makselon. "Method of the Moulding Sands Binding Power Assessment in Two-Layer Moulds Systems / Metoda oceny wielkości siły wiązania mas w układzie form dwuwarstwowych". Archives of Foundry Engineering 13, nr 2 (1.06.2013): 39–42. http://dx.doi.org/10.2478/afe-2013-0033.
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Abstract More and more foundry plants applying moulding sands with water-glass or its substitutes for obtaining the high-quality casting surface at the smallest costs, consider the possibility of implementing two-layer moulds, in which e.g. the facing sand is a sand with an organic binder (no-bake type) and the backing sand is a sand with inorganic binder. Both kinds of sands must have the same chemical reaction. The most often applied system is the moulding sand on the water-glass or geopolymer bases - as the backing sand and the moulding sand from the group of self-hardening sands with a resol resin - as the facing sand. Investigations were performed for the system: moulding sand with inorganic GEOPOL binder or moulding sand with water glass (as a backing sand) and moulding sand, no-bake type, with a resol resin originated from various producers: Rezolit AM, Estrofen, Avenol NB 700 (as a facing sand). The LUZ apparatus, produced by Multiserw Morek, was adapted for investigations. A special partition with cuts was mounted in the attachment for making test specimens for measuring the tensile strength. This partition allowed a simultaneous compaction of two kinds of moulding sands. After 24 hours of hardening the highest values were obtained for the system: Geopol binder - Avenol resin.
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Hachem, Rafika, Nassima Meftah i Ahmed Bouaziz. "A comparative analysis of the microstructural and physicochemical properties of alluvial and dune sands from northeast Algerian Sahara". Journal of Engineering and Exact Sciences 9, nr 6 (25.07.2023): 16222–01. http://dx.doi.org/10.18540/jcecvl9iss6pp16222-01e.
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This paper investigates the physical, chemical, and microstructural properties of two types of natural sand; alluvial sands and dune sand from the El-Oued region in the northeastern Algerian Sahara. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray Fluorescence (XRF), Scanning electron microscopy (SEM/EDS), and granulometry analysis have been performed. The FTIR and XRD analysis prove that the alluvial sand and dune sand consist of high percentages of ?-quartz (SiO2), low amounts of calcite (CaCO3), and gypsum minerals (CaSO4;2H2O). The chemical analysis confirmed that both types of sand have a high silica (SiO2) ratio, reaching 80% for dune sand and 70% for alluvial sand, besides very low quantities of Al2O3, Fe2O3, and K2O oxides. CaO content was higher in alluvial sand than in dune sand. The shapes of alluvial sand grain samples ranged from angular to well-rounded. However, the dune sands have shapes ranging from sub-angular to well-rounded. However, the dune sand is poorly graded sand with a mean grain size of 250?m; whereas, the alluvial sand is well-graded sand with a mean grain size of 406?m. These findings demonstrate that alluvial and dune sands are mineralogically stable and chemically suitable for use as fine aggregates in construction. Also, these sands could be significant sources of quartz minerals.
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Alutu, O. E., i B. K. Ifejika. "Strength Study of Concrete Made with Various Local Sands in Benin City, Nigeria". Advanced Materials Research 18-19 (czerwiec 2007): 21–26. http://dx.doi.org/10.4028/www.scientific.net/amr.18-19.21.
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The paper focuses on the effect which varying the type of sand used in concrete will have on the compressive strength of concrete and seeks to determine the suitability of each sand for use in concrete works. The sand samples used include Okhoro, Ikpoba, Ovia and Okhuahiaerosion sands and Ikpoba, Ovia and Okhuahia river sands. Particle size distribution of the sands was first determined and the result was used to design grades 20, 25, and 30 concretes to Department of Environment (DOE) mix design method. Twelve cubes were cast from one particular sand sample and three cubes were tested at 7, 14 and 28 days for each grade of concrete respectively .The result revealed that the sand samples that are well graded gave the highest compressive strength; while the poorly graded sands gave lower strengths. Okhuahia river sand gave the strongest concrete followed by Ikpoba, and Ovia river sands, Okhuahia, Ikpoba, Ovia and Okhoro erosion sands. Particle size distribution within a sand zone probably did not affect strength but the impurity content did. However, the inter-zonal differences in particle sizes probably did affect strength. The result also showed that only the river sands and Okhuahia erosion sand are good for concrete making.
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Kasprzak, Marek, i Michał Łopuch. "Sand: A Critical Component for Beach Volleyball Courts". Applied Sciences 12, nr 14 (10.07.2022): 6985. http://dx.doi.org/10.3390/app12146985.
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Beach volleyball is growing in popularity. However, the construction of beach sports courts away from the seashore requires the use of the right quality sand, the desired characteristics of which are defined by FIVB standards. We decided to test sand from 11 volleyball courts in Wrocław, Poland and sand from the Central Sport Centre-Olympic Preparation Centre (CSC-OPC) in Spała, the main training facility for Polish beach volleyball players. Laboratory tests showed that too coarse sand containing admixtures of dark minerals was used for most of the courts in Wrocław. The sand containing the properties most similar to FIVB standards is that at CSC-OPC. Even a small amount of silt found does not guarantee that a sandy surface will be dust-free. Silt can adhere to larger mineral grains and separate from them by mechanical impact or from crushing aggregates. In addition, we surveyed volleyball players. The players unequivocally interpreted the ease of play on finer-grained sands and the reduction of movement dynamics on courts with coarse-grained sand. Nevertheless, these are not the only factors determining their preference for their favourite court. Compliance with FIVB standards, however, guarantees comparable playing conditions.
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Eager, David, Chris Chapman, Yujie Qi, Karlos Ishac i Md Imam Hossain. "Additional Criteria for Playground Impact Attenuating Sand". Applied Sciences 11, nr 19 (22.09.2021): 8805. http://dx.doi.org/10.3390/app11198805.
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Falls within children’s playgrounds result in long bone and serious injuries. To lower the likelihood and severity of injury, impact attenuating surfaces (IAS) are installed within the impact area (fall zone). There are three primary IAS materials used, namely: granulated rubber products, wood fibre products, and sand. There is a deficiency with existing IAS test methods in that they do not take account of sand degradation over time. When children use the playground, sand degradation can occur when sand produces fines and smaller particles with low sphericity and angular which fill the voids between the sand particles. These fines and smaller particles tend to bind the sand and lower its impact attenuating performance. This paper proposes an additional IAS test to eliminate sands that degrade above an established threshold rate after installation due to normal usage. IAS degradation properties of fifteen IAS sands were tested including sand particle shape, sand particle distribution, percentage fines and sand particle degradation. This accelerated ageing test method is applicable only to sands and not rubber or wood fibre IAS products. The best IAS sands were sourced from quarries located on rivers that had eroded volcanic outcrops. These sands were shown to degrade the least and had little to no fines, and their particle shape was rounded to well-rounded. The most reliable source for good quality IAS sands on these rivers was on specific bends. The sand mined at these locations consistently had a tight particle size distribution.
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Jacobs, Trent. "How Wet-Sand Completions Became Key to Chesapeake’s Low-Cost Future". Journal of Petroleum Technology 73, nr 04 (1.04.2021): 29–31. http://dx.doi.org/10.2118/0421-0029-jpt.
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Matt Mantell wasn’t always sure that completing horizontal wells with wet sand was going to be as efficient as using smooth-flowing dry sand. But after proving how well it does work, and how much money it saves, the completions engineering advisor with Chesapeake Energy said the plan to use wet sand at every possible opportunity is moving “full-speed ahead.” Wet sand represents a new trend in the US shale sector that has spread from operator to operator. After the sand is washed free of unwanted particulates at the mine, it has historically been dried before being delivered to a wellsite. Wet sand is instead loaded straight from decanting piles. The gas-burning dryers are left off. Chesapeake’s numbers show that by using wet sand instead of dry sand, the operator saves about $11/ton. On a 10,000-ft lateral using 3,600 lb/ft, this translates to a savings of nearly $200,000, or 2% off the total well cost. In framing the impact of these reductions, Mantell said, “It’s right there with the type of shift we’ve made over the last few years to more regional sands. You’re looking at an opportunity to continue reducing the logistical cost, the trucking cost, from the mine to the wellsite.” Oklahoma City-based Chesapeake emerged from bankruptcy protection in February and is looking forward to leveraging the shale sector’s latest cost-saving evolutions in its renewed drive to become a low-cost shale producer. While this is easier said than done, wet proppants appear to be low-hanging fruit. As Chesapeake’s example demonstrates, successful adoption involves minimal trial and error. It also shows that the outlook for this trend will be bolstered by its lower energy inputs, which means wet-sand wells can boast slimmer carbon footprints. Gusto may be far from peaking, too. Chesapeake predicts that future mines will become small and mobile, further lowering capital costs. Learning the Ropes The operator’s first go with wet sand came in August 2019 during a refracturing operation at the Eagle Ford asset it acquired that same year in its purchase of WildHorse Resource Development. The trial in southeast Texas involved pumping wet sand into just a few stages, but it offered a low-risk opportunity to work through the hiccups that wet sand can introduce. One relatively minor issue discovered early on involved getting the wet sand to load evenly onto the conveyer belt that feeds the blending unit. The clumpy nature of wet sand led to a few big slugs of it hitting the blender all at once, making it difficult to meter just how much was going in. The issue was quickly worked out in part by simply paying greater attention to how the sand was loaded and unloaded, with the focus on spreading it out as evenly as possible. Adam Hoffman, a lead completions engineer in Chesapeake’s Eagle Ford asset, said the biggest learning, though, was that there is a “real fine line” between sand that is wet and sand that is too wet. If the moisture content As Chesapeake’s example demonstrates, successful adoption involves minimal trial and error. It also shows that the outlook for this trend will be bolstered by its lower energy inputs, which means wet-sand wells can boast slimmer carbon footprints. Gusto may be far from peaking, too. Chesapeake predicts that future mines will become small and mobile, further lowering capital costs.
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Meng, Lin, Ying Xin i Yu Sen Zhao. "Influence of Horqin Sandy Land Plant Sand Barrier on Soil Moisture". Advanced Materials Research 113-116 (czerwiec 2010): 1110–14. http://dx.doi.org/10.4028/www.scientific.net/amr.113-116.1110.
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In this paper, the shrub windbreak and sand-fixing sand barrier of Bairin Youqi in Chifeng in the east of Horqin Sandy Land is the research object, three different types of plant barriers including hedysarum laeve grid sand barrier, Salix gordejevii and hedysarum laeve grid sand barrier and caragana and hedysarum laeve patch sand barrier are respectively selected, and the shifting sandy land is selected as a contrast at the same time to study its influence on the soil moisture of sandy land in the method of field locating observation method from early May to late September of 2005. Except for the contrasted sandy land, the monthly average soil moisture in each layer of plant sand barrier presents a fluctuation trend. The monthly change trend of soil moisture in the 10~20cm soil layer of hedysarum laeve grid sand barrier is the same as that of caragana and hedysarum laeve patch sand barrier. The soil moisture in 20~40cm soil layer of the three plant barriers in every month shows a big change, with the fluctuation range larger than the contrasted sandy land. The 20~60 cm soil layer is the area where the roots of sand barrier plant are centralized, therefore, the soil moisture in the root intensive area is reduced. The monthly change trend of soil moisture in 60~80cm soil layer of hedysarum laeve grid sand barrier, caragana and hedysarum laeve patch sand barrier is the same as that of the contrasted sandy land. The monthly change trend of soil moisture in the 80~100 soil layers is basically same. The minimum value of monthly average soil moisture of all kinds of plant sand barriers appears when the contrasted sandy land is 1.40%, and the maximum value appears when caragana and hedysarum laeve patch sand barrier is 4.79%, 3.4 times higher than the contrasted sandy land. The annual dynamic condition of soil moisture can be divided into: consumption period from April to June, supply period from July to August, stable period in September, which shows that the plant sand barrier is favorable for increasing the soil moisture.
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Joshi, R. C., Gopal Achari, Shenbaga R. Kaniraj i H. Wijeweera. "Effect of aging on the penetration resistance of sands". Canadian Geotechnical Journal 32, nr 5 (1.10.1995): 767–82. http://dx.doi.org/10.1139/t95-075.
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The main objective of this study was to understand the effect of aging on the penetration resistance of freshly deposited sands. Two types of sand, locally available river sand used as masonry sand and Beaufort Sea sand, were selected for the study. The sands were allowed to age under a constant stress of 100 kPa in a specially designed apparatus in a dry state, as well as submerged in distilled water and in simulated sea water. Penetration resistance of the sand beds was measured periodically by pushing 4 probes into the sand bed. Mineralogical and fabric studies on freshly deposited and aged sand samples were conducted to detect the effect of aging, if any, on sand grains. The results indicate that aging significantly increases the penetration resistance of sands. The rate of increase in penetration resistance was higher for the submerged sand as compared with the dry sand. The increase in penetration resistance of the sand in a dry state was attributed to rearrangement of sand grains. In the submerged state, besides the rearrangement of sand particles, partial cementation caused by precipitation of salts and probably also silica on the sand grains and in the pores resulted in the larger increase in the penetration resistance. Key words : sand, aging, penetration resistance, freezing and thawing, sea water, distilled water.
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Secu, Cristian Vasilică, Cristian Constantin Stoleriu, Cristian Dan Lesenciuc i Adrian Ursu. "Normalized Sand Index for Identification of Bare Sand Areas in Temperate Climates Using Landsat Images, Application to the South of Romania". Remote Sensing 14, nr 15 (7.08.2022): 3802. http://dx.doi.org/10.3390/rs14153802.
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The expansion of bare sand surfaces indicates a tendency towards desertfication in certain periods as a result of the improper agricultural use of sand soils and of the significant changes in the climate in the past 30 years. The Normalised Sand Index (NSI) is a new index used to identify bare sand areas and their spatio-temporal evolution in SW Romania. Landsat scenes (1988, 2001, 2019), spectral and soil texture analysis (36 samples), covariates (e.g., soil map), and field observations allowed for the validation of the results. The performance of the NSI was compared with indices from the sand index family (e.g., Normalized Differential Sand Areas Index) and supervised classifications (e.g., Maximum Likelihood Classification) based on 47 random control square areas for which the soil texture is known. A statistical analysis of the NSI showed 23.6% (27,310.14 hectares) of bare sands in 1988, followed by an accelerated increase to 47.2% (54,737.73 hectares) in 2001 because of economic and land-use changes, and a lower increase by 2019, which reached 52.5% (60,852.42 hectares) due to reforestation programs. Compared to the NSI, the bare sand areas obtained with the tested indicator were almost 20% higher. The traditional classification shows smaller areas of bare sands but uses a higher complexity of land use classes, while the producer accuracy values are lower than those of the NSI. The new index has achieved a correct spatial delimitation of soils in the interdune-dune and major riverbed-interfluvial areas, but it is limited to the transition Arenosols-Chernozems by humus content and agrotechnical works. The new spectral index favours bare sand monitoring and is a fast and inexpensive method of observing the desertification trend of temperate sandy agroecosystems in the context of climate change.
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Park, Seo Kyoung, Jang K. Kim i Han Gil Choi. "Effect of substratum types on the growth of assimilators and stolons of Caulerpa okamurae (Bryopsidales, Chlorophyta)". Algae 37, nr 4 (15.12.2022): 293–99. http://dx.doi.org/10.4490/algae.2022.37.12.10.
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To examine the effects of substratum types on the growth of Caulerpa okamurae, sand surface and sand burial experiments were conducted. Five assimilators (erect fronds) per replicate were cultured for 15 d on the surface of three different treatments: fine sand (200 μm), coarse sand (600 μm), and no sand (control). Also, three stolons and three assimilators were buried by fine grain or coarse grain sands and incubated for 15 d. In both experiments, other culture conditions included 25°C, 30 μmol photons m-2 s-1, and 16 : 8 h L : D (light : dark). In both experiments, stolon + assimilator-, assimilator-, and stolon-weights were measured. Relative growth rates (RGRs) of stolon + assimilator weights ranged from 0.43 to 1.95% d-1 at no sand and fine sand treatment, respectively. RGRs for the weight of stolon + assimilator and new assimilators were significantly greater on the fine- and coarse sand surface than the control. In the burial experiments, RGRs of stolons (4.28% d-1 at coarse sand and 5.57% d-1 at fine sand, respectively) were significantly greater than those of assimilators (1.38% d-1 at fine sand and 1.82% d-1 at coarse sand, respectively). When stolons were buried, RGRs for assimilators were greater at the fine sand than at the coarse sand treatment. On the other hand, RGRs of buried assimilators for total frond weights and for newly produced stolons were significantly greater at the coarse sands than at the fine sands. In conclusion, C. okamurae grew well with all substrates of sands and showed better growth on fine sands than coarse ones. This result suggests that the growth of stolons and assimilators of C. okamurae is stimulated after stable attachment to the sand substrates by rhizophores. In addition, stolons showed higher growth rates than the assimilators in the sand burial states, indicating that stolons are more tolerant to low light than assimilators of C. okamurae.
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Pallares, Jesus David Montero, Chenxi Wang, Mohammad Haftani i Alireza Nouri. "Aperture Design Optimization of Wire-Wrapped Screens for SAGD Production Wells". Eng 4, nr 2 (6.04.2023): 1058–70. http://dx.doi.org/10.3390/eng4020062.
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Wire-wrapped screens have been established as one of the primary sand control devices in Steam-Assisted Gravity Drainage (SAGD) wells due to the high open-to-flow area and superior plugging attributes. However, their design is still a point of interest for thermal operations. Generally, existing approaches rely on one or more particular points of reservoir sands’ particle size distribution (PSD) and rules of thumb inferred from other devices like the slotted liners. This study used Sand Retention Testing (SRT) to analyze the performance of WWS under various testing conditions, which were neglected in the current design criteria. The experimental investigation leads to a set of graphical design criteria that provide an optimum aperture size window. The results show that the sand retention performance of WWS is highly dependent on the flow velocities of the wetting phase. Moreover, the testing showed satisfactory plugging performance of WWS even with narrow aperture sizes, proving a superior performance for low-quality oil sands.
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Fazhan, Hanafiah, Khor Waiho, Alexander Chong Shu-Chien, Youji Wang, Mhd Ikhwanuddin, Muyassar H. Abualreesh, Nor Azman Kasan i in. "Fine sand facilitates egg extrusion and improves reproductive output in female mud crab genus Scylla". PeerJ 10 (23.08.2022): e13961. http://dx.doi.org/10.7717/peerj.13961.
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Mud crabs (genus Scylla) are gaining attention as potential aquaculture species due to their lucrative market price and high demand. One of the essential components of mud crab culture is broodstock quality. The optimisation of mud crab broodstock culture currently focused on its nutritional aspects and common rearing parameters, including stocking density and temperature. The use of sandy substrate to induce egg extrusion in female Scylla broodstock is common; however, its optimisation has never been conducted. This study investigated (1) the substrate association of two Scylla species (S. olivacea, S. paramamosain) during broodstock conditioning until egg extrusion when the choices of fine (66.99 ± 14.48 μm) and coarse (656.17 ± 38.13 μm) sands were given; (2) the female reproductive output when S. olivacea females were individually exposed to either fine sand, coarse sand, or no sand treatments. Females, spawners and non-spawners, of S. olivacea and S. paramamosain were associated with fine sand and none was observed to bury in the coarse sand tray. The occurrence of egg extrusion was not significantly different between species but moderately associated with the duration of visits (stayed in sand for 1 d, 2 d, ≥3 d). The final incubation period in the sand tray was more than 2 days in all cases, except for one female S. paramamosain (buried in the sand for 1 day prior to egg extrusion). When no choice was available, the highest percentage (58.3%) of females extruded eggs in fine sand treatment, followed by coarse sand treatment (33.3%), and no sand treatment (8.3%). Sand type influenced the weight of egg clutch, total egg number, fecundity, and clutch size. These results suggest that fine sand (<70 μm) substrate should be incorporated into Scylla broodstock rearing to maximise female reproductive output.
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Yannick, Tchedele Langollo, Bilkissou Alim, Njoya Mfokou Abdou Nasser, Oumar Ali Taïga, Njoya Moussa Jalil, Belinga Essama Boum Raphael i Mache Jacques Richard. "Comparative Study of Mortars Made with Sands of Different Geological Origin". Advances in Materials Science and Engineering 2023 (28.11.2023): 1–15. http://dx.doi.org/10.1155/2023/5139325.
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The present work is a comparative study of sand mortars from various geological origins to highlight their influence on mortar qualities. Five different sands and the cement CEM II/B–P 42.5R were used to produce mortars with similar water/cement ratios (W/C). These are the “Sanaga” sand from the Sanaga River, the “Wouri” sand from the Wouri River, the Nyambaka basalt sand, the Meiganga granite sand, and the Leboudi gneiss sand. The physical, chemical, and mineralogical features of these sands were used to characterize and classify them. They were then used to formulate mortars, which were analyzed and compared. According to the results of the mortar setting time tests, the initial setting time ranges from 195 minutes for Sanaga sand mortar (MS04) to 210 minutes for gneiss sand mortar (MGN03), passing Wouri sand mortar (MW05) with 200 minutes, basalt sand mortar (MB01) with 198 minutes, and granite sand mortar (MGR02) with 196 minutes. The final setting time ranged from 496 minutes (MGR02) to 510 minutes (MGN03), with an average of 300 minutes added to the initial setting time. The flexural strength tests of the mortars reveal that crushed sands outperform alluvial sands. They range from 1.64 to 2.18 MPa after 2 days, 3 to 3.90 MPa after 7 days, and 7 to 14.84 MPa after 28 days. The results of the compressive strength tests show that quarry sand mortars have greater average compressive strengths than alluvial sand mortars, with basalt sand providing the greatest performance. These strengths range from 6.35 to 10.83 MPa after 2 days, 7.55 to 18.96 MPa after 7 days, and 22.81 to 34.58 MPa after 28 days, with the MB01 being the best sand. These findings reveal that the geological origin of sands, which specifies certain of their physicochemical and mineralogical attributes, has an impact on the properties of mortars. This impact is also influenced by granulometry and organic matter concentration.
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Skrzyński, M., R. Dańko i J. Kamińska. "Reclamation of Mixtures of Spent Sands of Inorganic and Organic Type". Archives of Foundry Engineering 13, nr 4 (1.12.2013): 93–96. http://dx.doi.org/10.2478/afe-2013-0089.
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Abstract The results of investigations of the reclamation of spent moulding and core sands, originated from one of the Polish foundry plants, are presented in the paper. Four mixtures consisting of two types of spent sands (spent moulding sand and spent core sand) were subjected to the regeneration process. Each tested mixture consisted of an inorganic type spent moulding sand and of an organic type spent core sand. Proportions of mutual fractions of spent moulding and core sands in mixtures was 70%-30% and was representative for the waste sands from the foundry, from which these sands originated.
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Abdikerem, Xamxinur, Mamtimin Gheni, Abdurahman Ablimit i A. Fang Jin. "Dynamics and Numerical Modeling of Sandy Desert Morphology Caused by Aeolian Transport of Sand Particles". Key Engineering Materials 462-463 (styczeń 2011): 1038–43. http://dx.doi.org/10.4028/www.scientific.net/kem.462-463.1038.
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Wind caused the much sediment fluxes leading to both erosion and deposits in the sandy desertification area, and the much kind of beautiful sandy desert morphologies are formed. This is really crucial to the development of the dynamic behaviour of aeolian transport of sand particles. The sand desert morphologies are representing significant information archives for understanding the desertification problem. Dynamics and numerical modeling provides an essential tool for studying the aeolian transport of sand particle and morphology of sand desert such as ripple and dune. In this study, the mathematical models based on the dynamics are analyzed by considering the several keys as saltation, creep, suspension, avalanche and its threshold condition etc. for sand morphology forming processes. Then due to sand flow field real characteristics, the establishing process of stream flow field are analyzed, and the implication relationships as well as the coupling process between uniform stream flow field and the sand flow field are analyzed. Finally, the sand flow field models is discretized, and different kinds of sandy desert morphology are simulated by considering the sand particle size and mass in fixed, semi-fixed and free sand flow field area.
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Ahlbäck, Lina, i Åsa Berggren. "The effect of landscape structure and habitat composition on the presence of the threatened parasitic sand-living beetle Apalus bimaculatus (Coleoptera: Meloidae)". Canadian Entomologist 145, nr 6 (28.08.2013): 626–38. http://dx.doi.org/10.4039/tce.2013.43.
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AbstractApalus bimaculatus (Linnaeus) (Coleoptera: Meloidae) is a beetle currently managed for conservation in Sweden. The species inhabits at-risk ephemeral and patchily distributed sandy habitats. However, little is known about its ecology and the factors important for its distribution. We censused 158 discrete sand patches within 31 potential sites for A. bimaculatus and examined which environmental variables predicted the probability of finding the beetle. Apalus bimaculatus was found at 17 sites, its presence at sand-patch scale was positively correlated with sand-patch area, sand temperature, and medium-sized sand grains. Although the beetle is assumed to be a parasite on the solitary bee, Colletes cunicularius (Linnaeus) (Hymenoptera: Colletidae), presence of the bee was a very weak predictor for A. bimaculatus, while other sand-living Hymenoptera were a strong predictor. At site-level scale, the beetle was positively correlated with total amount of sandy habitat and presence of sand-living Hymenoptera. Our study suggests that management strategies for this species should not consider sandy habitats equally. Rather, management efforts should focus on maintaining sites with larger total sandy areas, creating larger sand patches with medium-grained sand and a high degree of sun exposure. We also highlight that biotic interactions between the beetle and sand-living Hymenoptera are still poorly understood but potentially important for successful A. bimaculatus management.
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Kotwicki, Artur, Mirza Hassan Baig, Yngve Bolstad Johansen, Guro Leirdal, Brage Vikaune Aftret, Odd Arne Sandstad, Anne Mette Anthonsen, Bruis Gianotten, Tor Arne Hansen i Mauro Firinu. "Evaluating Petrophysical Properties and Volumetrics Uncertainties of Sand Injectite Reservoirs – Norwegian North Sea". Petrophysics – The SPWLA Journal of Formation Evaluation and Reservoir Description 63, nr 1 (1.02.2022): 82–103. http://dx.doi.org/10.30632/pjv63n1-2022a5.
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Sand injectites on the Norwegian Continental Shelf have proven their commercial significance. Some are already producing, e.g., Volund, Viper, Balder, Ringhorne, and Kobra Fields, while others such as in production licenses (PL) 340 and 869 have recently been discovered and appraised. Extensive literature on the geology of sand injectites has been published (e.g., Jenssen et al., 1993; Jolly and Lonergan, 2002; Huuse et al., 2003; Hurst et al., 2005). However, few references are available on the petrophysical and geophysical aspects of sand injectite reservoirs. This paper discusses the petrophysical properties of sand injectite facies, dykes, sills, and brecciated sands, along with their identification from seismic data. A perception that volumetrics of sand injectite reservoirs cannot be reliably evaluated is assessed. Sand injectites in PL 340 and 869 were interpreted as remobilized sands from the Hermod and Heimdal Formations of Paleocene age injected into the overlying Balder Formation and Hordaland Group mudstones of Eocene age. The mudstones acted as a seal, forming an intrusive stratigraphic trap. The trap geometry varied locally depending upon the dyke and sill geometries of the sandstone. Dykes had large vertical reach with the corresponding high-hydrocarbon column, while sills had low-vertical relief with large lateral extent. Intervals of brecciated sands were also observed within the injectite complex, especially where sands were thin. These brecciated sands contained large amounts of angular mudstone clasts of different dimensions suspended in an overall sandy matrix. Close examination of cored dykes made it possible to observe this, while it might not be as obvious when looking at bulk well logs. Petrophysical-log responses for clean sills and dykes behaved the same way as they would in a clean sandstone reservoir. If sills and dykes were very thin, they would also risk not being counted as net or pay (Suau et al., 1984; Dromgoole et al., 2000; Flølo et al., 2000;). Such errors can impact in-place volumes in a significant way. Sills appeared as blocky clean sand on logs, but it was difficult to differentiate a dyke from a sill or thin sands using logs. Dykes are high-angle features and are identified either by core studies or borehole images when intersected by a well or, if large enough, observable on seismic. Brecciated sand intervals appeared with cm-to-dm-scale mudstone clasts suspended in sand with approximately 40 to 60% net to gross. Log responses over these intervals indicated shaly sand or thin sands. Resistivity and thermal neutron porosity logs were highly affected by the shale clasts. For this reason, a fractional net/gross interpretation technique was used to evaluate the sand content and hydrocarbon pore volume. To further verify these results, they were compared to observations directly on the core. To qualify to what extent petrophysical logs and interpreted products thereof can be relied on to evaluate hydrocarbon volumes of sand injectite reservoirs, a high-resolution petrophysical interpretation was generated using a computerized tomography (CT) scanned core image. Core image sand counting and image-derived high-resolution bulk density logs with shale-corrected resistivity were used. Results of this high-resolution interpretation featured an excellent match with routine core analysis data and manual core observations in the core laboratory. The fractional net/gross method used is the modified Thomas-Stieber method (Johansen et al., 2018). Its results compared well to the high-resolution CT-scan image results and better evaluated the hydrocarbon pore volume of sand facie compared to the conventional bulk formation evaluation approach. This result confirms that the Thomas-Stieber method can be used for brecciated rocks, which leads to some useful recommendations on how to best log and perform a petrophysical evaluation in such reservoirs.
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Li, Zhenhua, Zihao Zhu, Yahong Zhao, Cong Zeng i Peng Zhang. "Experimental Investigation on the Diffusion Law of Polymer Slurry Grouted in Sand". Polymers 14, nr 17 (2.09.2022): 3635. http://dx.doi.org/10.3390/polym14173635.
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Polymer slurry is widely used in underground engineering treatment, but due to the concealed nature of underground projects, the diffusion pattern of slurry in the sand has been little studied. In this study, the basic physical properties of water-based polyurethane, oil-based polyurethane, and acrylate and epoxy resin were compared, and the performance of chemical grouted sands with different polymer slurry/sand mass ratios (PS/S) was tested. The higher the PS/S, the better the mechanical and impermeability properties of the chemical grouted sands. In this paper, water-based polyurethane was selected to carry out orthogonal tests on the diffusivity of slurry in sands. This experiment investigated the degree of influence of sand quality, grouting pressure and sand compactness on the diffusion of slurry in sands. The test results show that, in terms of factors affecting the final pressure of grouting, the sand density has the greatest influence, followed by the sand quality, and the grouting pressure is the smallest. In terms of slurry diffusibility, grouting pressure has the greatest influence, followed by sand compactness, and the sand quality is the smallest. The diffusion mechanism of slurry in the sand was deduced from the morphology of chemical grouted sands. Water-based polyurethane showed splitting-compression-penetration diffusion in sands of different grades, and the diffusion pattern of the slurry was not the same in low-pressure (1–1.5 MPa) grouting and high-pressure (2 MPa) grouting, and lateral splitting occurred in the case of high-pressure grouting diffusion.
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Fouad, Mohamed Riad. "Physical characteristics and Freundlich model of adsorption and desorption isotherm for fipronil in six types of Egyptian soil". Current Chemistry Letters 12, nr 1 (2023): 207–16. http://dx.doi.org/10.5267/j.ccl.2022.8.003.
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The soil type and temperature are considered important parameters that can influence the rates and equilibria of different environmental processes. Therefore, the adsorption and desorption isotherms of fipronil in clay loam, clay, sandy loam, sandy clay loam, sand and loamy sand soils at 25 and 50˚C was studied. The amount of fipronil adsorbed and desorbed by different soils was significantly influenced by the temperature. Adsorption was higher in clay loam, clay, sandy clay loam and sandy soil at 25°C, while sand soil and loamy sand soil at 50°C. The non-desorbed amount was greater at 25°C in different types of soil except for clay loam soil. The negative ΔG˚ indicated that the adsorption/desorption in different types of soil was spontaneous at different temperatures. The value of standard enthalpy change (ΔH˚) was positive in clay soil, sandy loam soil, sandy clay loam soil and loamy sand soil for adsorption and sandy loam soil, sand soil and loamy sand soil for desorption. Moreover, the standard entropy change (ΔS˚) was negative in soils for adsorption and desorption isotherms except clay loam soil. Adsorption and desorption isotherms trends as well as the values of the correlation coefficients indicated that the adsorption and desorption isotherms of fipronil in tested soils were fitted to the Freundlich model because the correlation coefficient is very close to 0.999.
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Peterson, Ivars. "Dry Sand, Wet Sand". Science News 152, nr 12 (20.09.1997): 186. http://dx.doi.org/10.2307/3980994.
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Stănilă, Anca-Luiza, Cătălin Cristian Simota, Iulian Răţoi, Aurelia Diaconu, Mihail Dumitru i Sorina Iustina Dumitru. "Research on Sandy Soils from Oltenia Plain and Their Cultivation". Journal of Applied Biotechnology 6, nr 2 (25.07.2018): 49. http://dx.doi.org/10.5296/jab.v6i2.13423.
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Sandy soils from Oltenia Plain occupies the largest area in the country, about 209.400 ha and are situated on terraces of the Danube, the Jiu and Olt River and west Oltenia Plain. The primary material of the origin of the sand in the south Oltenia is the Carpathians South of Olt and Jiu, the differences consisting of the amount somewhat less coarse sand by the Danube, rich in calcium carbonate thereof as compared to the sand and sandy soils from Left Jiu. The territory between Olt, Jiu, and Danube consists of two distinct areas: one field Leu-Rotunda, located in southeastern Oltenia. This field is a continuation of the surface of the plateau levatinului Piedmont. The second area is formed by terraces Olt, Jiu and Danube. This area has the absolute altitude between 110-140 m with slopes to the east and south. As such relief formations have shown sandy dunes and interdune form. Dunes had heights of 5-15 m and 100-500 m width were interdune. Area with sandy soils in southern Oltenia is crossed by a river system, represented by the Danube River to the south, Olt River to the east and west Jiu River. Plant growth and development of the sandy, is related to the presence of water, which has a decisive role. Low rainfall, high temperatures and Austru wind, warm and dry, make sands of Oltenia sometimes take the form of semi-desert. From an textural, in most cases, the percentage of coarse sand is higher and the lower sand on the dune and the interdune increase both the proportion of sand and the clay. In Oltenia Plain appear dominant cernisols represented by typical chernozems, calcic chernozems, cambic chernozems, gleyic chernozems and argic chernozems, which are added some luvisols of type reddish preluvosols and typical luvosols and some typical eutricambosols. Not missing hidrisols nor salsodisols, and in floodplains and terraces predominate protisols with distric psamosols and eutric aluviosols. Lately, as a result of pedoameliorative measures, such as shaping and leveling, were essential changes in both the forms of relief, and the main physical and chemical properties, disappearing dunes due to mobilization on higher ground sand and depositing the material in interdune. Excavated and deposited quantities of sand are varied both in terms of origin and physic and chemical properties. Production potential is medium. Requires to stem deflation, the increase in organic matter in the soil and especially in the areas set (level model), the fertilization and maintaining forest cover.
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Wallis, MG, DJ Horne i AS Palmer. "Water repellency in a New Zealand development sequence of yellow brown sands". Soil Research 31, nr 5 (1993): 641. http://dx.doi.org/10.1071/sr9930641.
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A series of sands on the west coast of the lower North Island, New Zealand, were studied to investigate the effects of time, topography and vegetation cover upon the development of soil water repellency. Severe repellency was measured with the molarity of ethanol droplet (MED) index in the Waitarere and Motuiti dune phase sands, of age <130 years and c. 500 years respectively. In each dune phase, the dune sands were more repellent than the lower lying soils of the sand plains. Low or zero MED values were measured in the 1600-6000 year old Foxton dune phase sands and 10 000-25 000 year old Koputaroa dune phase sandy loams under either pasture or native bush. There was no consistent relationship between bush or pasture cover and repellency severity in the Foxton and Koputaroa soils, however, the species composition of the pasture and bush differed. The Waitarere sand was the most repellent soil, despite a low organic carbon content. The carbon content profiles of most of the soils did not appear to be related to the respective MED profiles of repellency severity. The MED values of the surface layer from five dune sands were generally related inversely to the fulvic acid (FA) content and proportionally to the humic acid to fulvic acid ratio (HA/FA), which were measured in a previous study. The pH of the five soils ranged from 5.61 to 6.89, with no apparent relationship between pH and MED. A study of soil water content indicated that repellency reduced rainfall infiltration into the Waitarere and Motuiti sands and the Himatangi sand, found on elevated sand plains. The most severely repellent sands had the greater variability in soil water content after rainfall.
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Pratiwi, Wieke, Gaos Abdul Karim i Titi Rachmawati. "Local Silica Sand as a Substitute for Standard Ottawa Sand in Testing of Cement Mortar". Materials Science Forum 1000 (lipiec 2020): 220–26. http://dx.doi.org/10.4028/www.scientific.net/msf.1000.220.
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Compressive strength of cement mortar is an important parameter in the quality control of Portland cement. The limitation of Ottawa sand imports has prompted a study on the potential and utilization of local silica sand available in several regions in Indonesia. The purpose of this study was to investigate the potential and possibility of utilizing local silica sand from several regions in Indonesia including Bangka, Belitung, Sidrap (South Sulawesi Province) as a substitute for standard Ottawa sand in cement mortar testing. Evaluation of local silica sands consisted of SEM analysis, characterization of silica sands and testing of cement mortar compressive strength. Silica sands from Bangka, Belitung and Tuban had silica content of more than 90%, while that from Sidrap was more or less 90%. Based on the SEM analysis, characteristic of silica sands, and compressive strength of cement mortar, local silica sand from Sidrap (South Sulawesi Province) has a good potential to be used as a substitute for standard Ottawa sand in testing of cement mortar.
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Zhang, Rui, Hai Bao Liu, Si Hua Zhang, Gui Yin Zeng i Jian Qiao Li. "Finite Element Analysis in the Characteristics of Ostrich Foot Toenail Traveling on Sand". Applied Mechanics and Materials 461 (listopad 2013): 213–19. http://dx.doi.org/10.4028/www.scientific.net/amm.461.213.
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The ostrich foot toenail plays a crucial role in the process of ostrich foot traveling on sand. 3D laser scanner was used to measure the three-dimensional point clouds of ostrich foot toenail surface morphology, and the three-dimensional model of ostrich foot toenail was reconstructed by using reverse engineering technology. The finite element analysis in the interactions between ostrich foot toenail and sand was implemented by Abaqus and Hypermesh. The quasi-static analytical results of ostrich foot toenail inserting the sands showed that the groove structure of the toenail had a better sand fixation effects, the tiptoe structure was conducive to insert into the sands, and the inverted triangular structure of the toenail had the weak disturbance on the sands which produced the less resistance of the toenail inserting the sands. According to the velocity and the stress fields in the process of the ostrich foot toenail dynamically traveling on sand, ostrich foot toenail tiptoe could help to improve the thrust of traveling on sand, the groove area of the toenail played the effects of sand fixation and flow limitation in the process of ostrich foot toenail traveling on sand. Keywords: ostrich foot toenail, reverse engineering, model reconstruction, finite element simulation, sand fixation and flow limitation.
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Ding, Chun Sheng, Xiao Yan Ma, Ying Long Zhou i Ping Ning. "Experimental Study on Preparation and Pb2+ Adsorption Capability of Ferric Salt Modified Sands". Applied Mechanics and Materials 130-134 (październik 2011): 852–55. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.852.
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Ferric salt modified sands were prepared with quartz sand as a carrier and ferric salt coating by the two methods of repeat high-temperature process and repeat alkaline deposition process. The specific surface area of two ferric salt modified sands were detected, and their Pb2+ adsorption capability in different conditions were also described in this paper. The results showed that the specific surface area of ferric chloride and ferric nitrate modified sand was 2.468m2/g and 4.247m2/g respectively, which was 6.910 and 12.612 times more than that of raw quartz sand. In the neutral pH condition, the removal efficiency of Pb2+ by raw quartz sands was approximately 37%, in contrast, the removal efficiency reached 85% by ferric nitrate modified sand and over 90% by ferric chloride modified sand, and it was much higher than that of raw quartz sand.
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Benjelloun, Mohamed, Rachid Bouferra, Hassan Ibouh, Frederic Jamin, Ismail Benessalah i Ahmed Arab. "Mechanical Behavior of Sand Mixed with Rubber Aggregates". Applied Sciences 11, nr 23 (1.12.2021): 11395. http://dx.doi.org/10.3390/app112311395.
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The main objective of this study is to compare the mechanical behavior of two sands (Hostun or Dune sands) mixed with crushed rubber obtained from used tires. However, it is essential to ensure that his geotechnical application do not result in long-term negative impacts on the environment. The chemical properties of these two sands are given by energy dispersive analysis X-ray fluorescence spectrometry. The mineral composition of these two sands is performed by X-ray diffractometry. The morphological characteristics of the sand grains are given by the analysis of the images of the two sands given by the scanning electron microscope. This study is based on 120 direct shear tests performed on sand-rubber aggregate mixtures. The results show that the rubber content of the aggregates has a significant effect on the shear strength of sand-rubber mixtures in both cases of sand. In fact, the shear strength of the sand-rubber mixture increases with increasing crushed rubber up to 20% for different normal stresses. The analysis of the test results also shows the effect of the angular shape of the sand grains on the interparticle friction. The contribution of the structure effect in the mobilized friction is analyzed by comparing the shear test results of Hostun and dune sand mixtures.
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Khouadjia, M. L. K., K. Abdou, A. A. Belkadi, O. Kessal i B. Mezghiche. "Effect of Sands on the Evolution of the Modulus of Deformability and Longitudinal and Transverse Elasto-Instantaneous Deformations as a Function of the Relative Constraint in Concrete". Journal of Applied Engineering Sciences 12, nr 2 (1.12.2022): 185–92. http://dx.doi.org/10.2478/jaes-2022-0025.
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Abstract The production of crushed sand is accompanied by the production of fine particles. The proportion of these fine particles varies from one sand to another. The current publications of standards for reference in the construction industry have been adapted by increasing the limit of fine particles in crushed sand, but this is insufficient because sands with high rate of fine particles are not used in the industry. The principal objective of this study is to investigate the influence of crushed sands with different mineralogical natures (limestone and siliceous) and with varying proportions of fine particles on the evolution of the modulus of deformability and of longitudinal and transverse Elasto-instantaneous deformations. The experimental results showed that the longitudinal and transverse Elasto-instantaneous deformations and the modulus of deformability varied according to the nature of the sands (river sand, quarry sand, dune sand) and according to the fine content of the sands. Logarithmic regressions showed an accurate fit for the correlation coefficient R2. The test results demonstrated that deformations are influenced by sand type and indicated an optimal of 10% of fine particles. Empirical equations can predict the modulus of deformability from prismatic concretes.
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Ngo, Chi Kim Thi, Long Van Hoang, Binh Van Phan, Tinh Nguyen Trinh, Trung Tu Do, Hiep Huu Nguyen i Nghiem Van Dao. "The characteristics of the surface sediments in Co To island". Journal of Mining and Earth Sciences 61, nr 2 (29.04.2020): 33–40. http://dx.doi.org/10.46326/jmes.2020.61(2).04.
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552 grain size samples and 33 mineral quality defined samples have been collected in the Co To island, Tonkin Bay of Vietnam, to study the distribution and the sediment provenance. The field investigation method, the grain analysis, and the detrital composition examination method have been used to study the characteristics of the surface sediments in Co To island. The obtained results show that the surface sediments in the area consist of ten different fields, namely: sandy gravel, gravelly sand, sand, gravelly muddy sand, sand mixed gravel, muddy sand, gravelly mud mixed sand, silty sand, muddy sandy gravel, and sandy mud. The mineral component method shows that quartz is the main contain of the surface sediment (72,0÷90,6%), less rock detritus, felspat, mica, and very few of the shells. It is to confirm that the continent is the main primary material source of the study area. The distribution of the sediment is complicated. As the East-Southeast side of the research area, the sediment distribution following gravity way, coarse grain near the shore (gravel, sandy gravel,…), finer grain far off the shore (gravelly muddy sand, silty sand,…), choice level is very low. Which This is saying that the movement of sediment in the area is dominant, ; the flow energy is governed by the topography near the island and seafloor. In tMhe meanwhile, the west-northwest side, the topography of seafloor is the complicated, coarse sediment grains (gravel, sand), ); the roundness is bad, which is saying that the hydrodynamic flow there plays an important role in the sediment distribution.
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Sun, Jimin. "Origin of Eolian Sand Mobilization during the Past 2300 Years in the Mu Us Desert, China". Quaternary Research 53, nr 1 (styczeń 2000): 78–88. http://dx.doi.org/10.1006/qres.1999.2105.
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AbstractEolian sand dunes and sand sheets are extensive in the semiarid regions of northern-central China. Previous studies indicated that these eolian sands mainly formed during historical times. However, the sand sources and their reworking processes have not been well studied, and even the reasons for their occurrence are still controversial. Field investigation and sedimentary evidence indicate that both the inner Mu Us Desert and its southern marginal region, both sources of modern eolian sand, are largely associated with reworking of sands of the last glaciation. Based on geological, documentary, and archaeological data, three phases of land cultivation during the past 2300 years, together with historical droughts, high wind energy, and the easily reworked sand sources, largely account for the occurrence of active sand dunes and sand sheets in the Mu Us Desert.
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Alutu, O. E., i A. Omorogie. "The Influence of Vibration Time and Sand Type on the Compressive Strength of Sandcrete Hollow Blocks". Advanced Materials Research 62-64 (luty 2009): 24–30. http://dx.doi.org/10.4028/www.scientific.net/amr.62-64.24.
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The purpose of this study is to see if varying the vibration time and sand type during moulding of blocks would affect the strength of the blocks. To this end, seven types of sands: Okhuahie and Ovia river sands; Okhuahie, Ovia, Ikpoba flood and Okhoro erosion sands were collected for the study. A total of 315 blocks each in 150mm and 225mm sizes with cement to sand ratios of 1:6 were made using the seven brands of sand. The blocks were vibrated for 10, 15, 20, 25, and 30 seconds and tested for compressive strength at 7 days, 14 days and 28 days respectively. The result showed that the relationship between compressive strength of the blocks and the vibration time for various sand types was linear up to vibration time of 30 secs. The sand type also influenced the strength of the blocks as Okhuahie river sand gave the highest compressive strength followed by Ovia river sand and the least was Okhoro erosion sand. At least 52% increase in compressive strength of 150mm and 225mm sandcrete blocks were achieved by raising the vibration time from 15 seconds to 25 seconds in the seven types of sand and 100% increase was achieved by raising the vibration time from 15 to 30 seconds.
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Huang, An-Bin, Huai-Houh Hsu i Jia-Wei Chang. "The behavior of a compressible silty fine sand". Canadian Geotechnical Journal 36, nr 1 (8.08.1999): 88–101. http://dx.doi.org/10.1139/t98-090.
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Publications associated with sands are often limited to clean (i.e., little fines content), uniform, uncemented silica or quartz sand. On the other hand, the importance of mineral content, particle shapes, as well as gradation to the behavior of sand has long been recognized. Although systematic studies of sands other than clean quartz sand have been limited, there is increasing attention being paid to sands with an appreciable fines content. Because of a major construction project, extensive field and laboratory experiments were performed on a silty fine sand from Mai-Liao, which is located on the central west coast of Taiwan. Results show that Mai-Liao Sand (MLS), a silty sand, can be significantly more compressible than clean quartz sand under static load. The particles of MLS have moderate strength, and significant crushing can be induced by triaxial shearing. As a result, MLS has low dilatancy and a relatively small range of peak friction angles. Cone penetration tests in MLS were conducted in a calibration chamber. Analyses of the data indicate that interpreting cone tip resistance in MLS using methods developed based on clean quartz sand without considering the differences of compressibility can be unrealistic. This paper documents results of the experimental studies on MLS.Key words: silty fine sand, strength, dilatancy, compressibility, crushing, in situ test.
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Ward, PR, i JM Oades. "Effect of clay mineralogy and exchangeable cations on water repellency in clay-amended sandy soils". Soil Research 31, nr 3 (1993): 351. http://dx.doi.org/10.1071/sr9930351.
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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.
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Yang, Jianyu, Yanhui Cheng i Weichao Chen. "Experimental Study on Diffusion Law of Post-Grouting Slurry in Sandy Soil". Advances in Civil Engineering 2019 (3.03.2019): 1–11. http://dx.doi.org/10.1155/2019/3493942.
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In order to study the diffusion law of grouting slurry in sand areas, the grouting of cement slurry in sand was analyzed by the indoor grouting test under different water-cement ratios, grouting pressures, grouting amounts, and soil qualities, and the law of the post-grouting slurry is obtained. The results show that the grouting method is affected by the grouting pressure, water-cement ratio, grouting amount, and soil quality. Under the same grouting pressure, the diffusion modes of different water-cement ratio grouts in sands with different permeability coefficients, which are mainly manifested as osmotic diffusion, are basically the same; under the same water-cement ratio, when the grouting pressure is relatively small, the diffusion of modes of slurry is mainly osmotic in sand. The diffusion radius of cement slurry in sand has a good power function relationship with grouting pressure, water-cement ratio, permeability coefficient, and grouting amount. And, the empirical function model of slurry diffusion radius is proposed by regression analysis. The research results provide a certain theoretical and experimental reference for post-grouting in sandy areas.
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Quanrud, David M., Robert G. Arnold, L. Gray Wilson i Martha H. Conklin. "Effect of soil type on water quality improvement during soil aquifer treatment". Water Science and Technology 33, nr 10-11 (1.05.1996): 419–31. http://dx.doi.org/10.2166/wst.1996.0700.
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Bench-scale soil column experiments were performed at The University of Arizona to examine the effects of soil type and infiltration rate on the removal of wastewater organics during soil aquifer treatment (SAT). The suitability of such waters for potable uses following a combination of above-ground treatments and SAT polishing was under investigation. SAT was simulated in 1-meter soil columns containing repacked homogenized soils ranging from poorly graded sands to silty sands. Soils were obtained from existing and potential effluent recharge sites in Arizona. All columns received chlorinated/dechlorinated secondary effluent, ponded to a 25-cm depth above the soil surface, under alternating wet/dry conditions. Treatment efficiencies in biologically active and inhibited columns were compared to determine the mechanism(s) of water quality improvements and the sustainability of SAT. Water quality parameters included: (i) non-purgable dissolved organic carbon and (ii) UV absorbance at 254 nm (used as a measure of disinfection-by-product precursors). Differences in through-column removal of non-purgable dissolved organic carbon were significant for columns containing sandy loam (56%), sand (48%) and silty sand (44%). Removal of UV-absorbing organics was not significantly different for columns containing sand and sandy loam (22 and 20%, respectively). There was no significant correlation between infiltration rate and removal efficiency of either organic parameter for both soils.