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Статті в журналах з теми "Soil compacity"
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Ping, W. Virgil, Ching-Chin Ling, and Robert K. H. Ho. "Influence of Soil Suction and Environmental Factors on Drying Characteristics of Granular Subgrade Soils." Transportation Research Record: Journal of the Transportation Research Board 1714, no. 1 (January 2000): 98–106. http://dx.doi.org/10.3141/1714-13.
Повний текст джерелаАнотація:
According to contractors in Florida, construction problems have emerged because pavement soils hold excessive water and are difficult to dry and compact. Recent research on the effects of soil suction and environmental conditions on drying rate characteristics of six types of troublesome granular soils is presented. Two types of tests were conducted for the study: soil suction tests using the thermocouple psy-chrometer method and drying rate tests using an environmental chamber. The experimental results showed that both the soil suction and relative humidity had direct effects on the soil-drying rate. The drying rate decreased with an increase in soil suction for each soil type and also decreased with an increase in the percentage of fines. The influence of relative humidity on the soil-drying rate was much more significant than the effect of the temperature. The rate of water evaporation was extremely low for the soils with a higher percentage of fines when the relative humidity was high. The A-2-4 soils with greater than 20 percent of fines may have such a low drying rate in an environment with high relative humidity that they are difficult to handle during construction.
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Aust, W. Michael, Masato Miwa, James A. Burger, Steve C. Patterson, and Emily A. Carter. "Wet-Weather Timber Harvesting and Site Preparation Effects on Coastal Plain Sites: A Review." Southern Journal of Applied Forestry 28, no. 3 (August 1, 2004): 137–51. http://dx.doi.org/10.1093/sjaf/28.3.137.
Повний текст джерелаАнотація:
Abstract Increased interest in sustainable forestry has intensified the need for information on the interactions of forest soils, harvesting methods, site disturbances, and the efficacy of methods for ameliorating disturbances. On wet pine flats, such as those commonly found in the Atlantic and Gulf Coastal Plains, conditions such as frequent rainfall, low relief, and poor internal soil drainage often predispose forest soils to harvest disturbances and potential damage. Typical forest operations use heavy logging equipment, such as rubber-tired feller-bunchers and skidders. During dry soil conditions, these machines cause little soil disturbance, but under moist to saturated conditions, such operations may compact soils and interfere with normal soil drainage. Many studies have been conducted to characterize soil disturbance and site preparation effects on tree seedling survival and growth and to evaluate the amelioration effect of site preparation on disturbed soils. However, results are sometimes contradictory due to site specificity, and results have not been summarized in the context of pine plantation management. This article summarizes previous research results of the wet-weather harvesting and bedding effects on soil properties as related to loblolly pine (Pinus taeda) productivity for a variety of Coastal Plain region sites types. South. J. Appl. For. 28(3):137–151.
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Holmstrom, D. A., and M. R. Carter. "Effect of subsoil tillage in the previous crop year on soil loosening and potato yield performance." Canadian Journal of Plant Science 80, no. 1 (January 1, 2000): 161–64. http://dx.doi.org/10.4141/p99-001.
Повний текст джерелаАнотація:
Soil compaction under potato rotations can be a common problem in Prince Edward Island. This can be further aggravated by naturally occurring compact subsoils. A study was conducted at eight sites on sandy loam soils in three regions of Prince Edward Island to determine whether the recommended practice of subsoiling the fall prior to the potato crop would improve the physical condition of the soil and result in improved yields. The study found that subsoiling provided only a marginal improvement in soil physical conditions. Soil loosening did not increase potato yield or quality. Key words: Potato, subsoiling, yield response, potato quality
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Ho, Soo Ying, Mohd Effendi Bin Wasli, and Mugunthan Perumal. "Evaluation of Physicochemical Properties of Sandy-Textured Soils under Smallholder Agricultural Land Use Practices in Sarawak, East Malaysia." Applied and Environmental Soil Science 2019 (February 6, 2019): 1–14. http://dx.doi.org/10.1155/2019/7685451.
Повний текст джерелаАнотація:
A study was conducted in the Sabal area, Sarawak, to evaluate the physicochemical properties of sandy-textured soils under smallholder agricultural land uses. Study sites were established under rubber, oil palm, and pepper land uses, in comparison to the adjacent secondary forests. The sandy-textured soils underlain in all agricultural land uses are of Spodosols, based on USDA Soil Taxonomy. The soil properties under secondary forests were strongly acidic with poor nutrient contents. Despite higher bulk density in oil palm farmlands, soil properties in rubber and oil palm land uses showed little variation to those in secondary forests. Conversely, soils under pepper land uses were less acidic with higher nutrient contents at the surface layer, especially P. In addition, soils in the pepper land uses were more compact due to human trampling effects from regular farm works at a localized area. Positive correlations were observed between soil total C and soil total N, soil exchangeable K, soil sum of bases, and soil effective CEC, suggesting that soil total C is the determinant of soil fertility under the agricultural land uses. Meanwhile, insufficient K input in oil palm land uses was observed from the partial nutrient balances estimation. In contrast, P and K did not remain in the soils under pepper land use, although the fertilizers application by the farmers was beyond the crop uptake and removal (harvesting). Because of the siliceous sandy nature (low clay contents) of Spodosols, they are poor in nutrient retention capacity. Hence, maintaining ample supply of organic C is crucial to sustain the productivity and fertility of sandy-textured soils, especially when the litterfall layers covering the E horizon were removed for oil palm and pepper cultivation.
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Papatheodorou, Effimia M., Spiros Papakostas, and George P. Stamou. "Fire and Rhizosphere Effects on Bacterial Co-Occurrence Patterns." Microorganisms 11, no. 3 (March 19, 2023): 790. http://dx.doi.org/10.3390/microorganisms11030790.
Повний текст джерелаАнотація:
Fires are common in Mediterranean soils and constitute an important driver of their evolution. Although fire effects on vegetation dynamics are widely studied, their influence on the assembly rules of soil prokaryotes in a small-scale environment has attracted limited attention. In the present study, we reanalyzed the data from Aponte et al. (2022) to test whether the direct and/or indirect effects of fire are reflected in the network of relationships among soil prokaryotes in a Chilean sclerophyllous ecosystem. We focused on bacterial (genus and species level) co-occurrence patterns in the rhizospheres and bulk soils in burned and unburned plots. Four soils were considered: bulk-burnt (BB), bulk-unburnt (BU), rhizosphere-burnt (RB), and rhizosphere-unburnt (RU). The largest differences in network parameters were recorded between RU and BB soils, while RB and BU networks exhibited similar values. The network in the BB soil was the most compact and centralized, while the RU network was the least connected, with no central nodes. The robustness of bacterial communities was enhanced in burnt soils, but this was more pronounced in BB soil. The mechanisms mainly responsible for bacterial community structure were stochastic in all soils, whether burnt or unburnt; however, communities in RB were much more stochastic than in RU.
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Cucci, Giovanna, Giovanni Lacolla, Marcello Pagliai, and Nadia Vignozzi. "Effect of reclamation on the structure of silty-clay soils irrigated with saline-sodic waters." International Agrophysics 29, no. 1 (January 1, 2015): 23–30. http://dx.doi.org/10.1515/intag-2015-0005.
Повний текст джерелаАнотація:
Abstract The objective of the work was to evaluate, by using the micromorphometric method, the effects of reclamation on porosity of two different clay loam soils irrigated with saline-sodic waters. Soil samples of the Ap horizon were put in cylindrical containers and irrigated with 9 types of saline-sodic waters (3 levels of salinity combined with 3 levels of sodicity). After a 4-year period, correction treatments were initiated by addition of calcium sulphate and leaching until electrical conductivity and sodium absorption ratio values of the drainage water matched 3 dS m-1 and 9, respectively. After 2 years of correction treatments, undisturbed soil samples were taken from the surface layer and soil thin sections for porosity measurements. Both soils did not show critical macroporosity values (> 10%, below this threshold a soil is classified as compact). Nevertheless, the soils exhibited a different behaviour: total porosity of the Pachic Haploxeroll soil was not affected by difference in water salinity and alkalinity; on the contrary, the Udertic Ustochrept soil showed a lower porosity associated with higher salt concentration in the irrigation waters. This may be due to the different iron and aluminium sesquioxides content and, as a consequence, a different effect on soil aggregate stability.
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Vis, Benjamin N., Daniel L. Evans, and Elizabeth Graham. "Engagement with Urban Soils Part II: Starting Points for Sustainable Urban Planning Guidelines Derived from Maya Soil Connectivity." Land 12, no. 4 (April 15, 2023): 891. http://dx.doi.org/10.3390/land12040891.
Повний текст джерелаАнотація:
Using the Precolumbian lowland Maya model of urban soil connectivity discussed in Part I, we review how soil connectivity can transition into urban planning policy and, by extension, could ultimately become codified as vantages and guidelines for urban design. In Maya agro-urban landscapes, the interspersion of open and green space with construction and paving provides edges (or interfaces) between sealed and unsealed soils at which the potential for soil connectivity manifests. These edges create an undeniable opportunity for urban planning to determine methods, guidelines, and conditions that can enhance soil connectivity. We argue that adequate attention to soils in urban sustainability goals would counteract misconceptions about the compact city paradigm and compensation for soil sealing in urban practice. Through preserving and increasing urban soil availability, proximity, and accessibility, advisory policies can stimulate shared values and everyday behaviours that reinforce the responsible and productive use of urban soils. Such urban planning can enable and encourage widespread participation in urban soil management. To promote policymaking on urban soils, we assess the importance and challenges of using urban green space as a proxy for the presence of urban soils. Our review suggests that urban green space offers high potential for use in urban planning to develop habit architectures that nurture soil-oriented pro-environmental behaviour. However, we also acknowledge the need for consistent and systematic data on urban soils that match sustainable urban development concepts to assist the effective transition of soil connectivity into urban planning codifications. Formulating adequate soil-oriented planning guidelines will require translating empirical insights into policy applications. To this end, we propose methods for enhancing our understanding and ability to monitor urban soil connectivity, including onsite surveys of land-use and bottom-up experience of soils, the mapping of the edges between sealed and unsealed soils, and using landscape ecological scales of analysis. In conclusion, we position soil care and connectivity as a primary task for urban planning and design and digest our findings and empirical vantages into concrete starting points devised as instruments to support urban planning in achieving soil codification.
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Nickayin, Samaneh Sadat, Francesca Perrone, Barbara Ermini, Giovanni Quaranta, Rosanna Salvia, Filippo Gambella, and Gianluca Egidi. "Soil Quality and Peri-Urban Expansion of Cities: A Mediterranean Experience (Athens, Greece)." Sustainability 13, no. 4 (February 14, 2021): 2042. http://dx.doi.org/10.3390/su13042042.
Повний текст джерелаАнотація:
Soil loss and peri-urban settlement expansion are key issues in urban sustainability, with multi-disciplinary implications that go beyond individual ecological and socioeconomic dimensions. Our study illustrates an assessment framework diachronically evaluating urbanization-driven soil quality loss in a Southern European metropolitan region (Athens, Greece). We tested the assumption that urban growth is a process consuming high-quality soils in a selective way analyzing two spatial layers, a map illustrating the diachronic expansion of settlements at five time points (1948, 1975, 1990, 2000, and 2018), and a geo-database reporting basic soil properties. The empirical results showed that the urban expansion in the Athens region took place by consuming higher- quality soil in fertile, mostly flat, districts. It entailed a persistent soil quality decrease over time. This trend globally accelerated in recent years, but in a heterogeneous way. Actually, newly built, more compact areas expanded on soils with lower erosion risk than in the past. Besides, low-density land take is likely to be observed in soils with moderate-high or very-high qualities. These evidences reflect the need for a comprehensive evaluation of complex processes of land take informing spatial planning for metropolitan sustainability.
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Lavkulich, L. M., and J. M. Arocena. "Luvisolic soils of Canada: Genesis, distribution, and classification." Canadian Journal of Soil Science 91, no. 5 (October 2011): 781–806. http://dx.doi.org/10.4141/cjss2011-014.
Повний текст джерелаАнотація:
Lavkulich, L. M. and Arocena, J. M. 2011. Luvisols of Canada: Genesis, distribution, and classification. Can. J. Soil Sci. 91: 781–806. Luvisols link the soil continuum on the Quaternary landscapes. These soils are developed from parent materials rich in Ca and Mg in a relatively humid climate. An acidic eluvial horizon overlying a phyllosilicate-enriched illuvial Bt horizon is the common horizon sequence in Luvisolic soils. Lessivage or the translocation of clays with minimal chemical alteration is the characteristic soil-forming process and results to the diagnostic Bt horizon with well-developed, oriented clay skins or cutans. These soils commonly form intergrades with Chernozems, Podzols and Vertisols. With time, the eluvial horizons experience increased chemical weathering and further release of sequioxides to form Brunisolic and Podzolic sequences within the eluvial Ae in biseqeual soils. Lessivage significantly influences several ecosystem functions of soils. The high amounts of phyllosilicates in the Bt horizon serve as one of the most active sorption sites in soils for metals and organic materials including soil carbon. Sorption of cations takes place through cation exchange reactions and determines the availability of cations to plant roots as well as in the “colloid facilitated transport” of strongly sorbing metals and organic pollutants. Clays in Bt can be restrictive to water and air movement as well as to root growth and distribution. Agricultural and forestry practices such as tillage can compact the structure of Luvisols and may decrease soil productivity.
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Akyıldız, Mehmet Hayrullah, and Ergün Akbaş. "BASİT VE ÇOKLU REGRESYON ANALİZLERİ İLE KOMPAKSİYON PARAMETRELERİNİN TAHMİN EDİLMESİ VE F TESTİ İLE ANLAMLILIĞININ İNCELENMESİ." e-Journal of New World Sciences Academy 15, no. 4 (October 31, 2020): 186–95. http://dx.doi.org/10.12739/nwsa.2020.15.4.1a0461.
Повний текст джерелаАнотація:
Compaction is the compaction of the moist soil by laying it in layers, rolling it by applying vibration. Compaction is widely used both for the frequency control of road embankments and embankment dams and in other important engineering projects. Therefore, it is important to determine the compaction parameters correctly. The lack of sufficient laboratory equipment at the construction sites and the limited deadline of work increased the importance of correlation equations. If there are sufficient data and results are obtained within tolerable safety limits, it is considered appropriate to use statistics in estimation of compaction parameters. This situation provides a gain both in terms of economy and time. In the study, the compaction parameters were tried to be estimated by subjecting the soil index properties of Adıyaman Balkar, Çelik and Pınaryayla Ponds to simple and multiple regression analyzes. First, the data of the soils belonging to the ponds were used, then, as a result of the sieve analysis, the index properties of fine-grained soils containing only clay and silt were evaluated and compaction parameters were tried to be determined. Simple and multiple regression analyzes were made with the help of the Eview program, where the statistical analysis of the existing data was made, and the statistical significance of the obtained models was examined by performing the F test. It was determined that higher correlations were obtained compared to other sample data, especially by using the data of samples that do not contain sand and gravel material.
Дисертації з теми "Soil compacity"
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Richer, de Forges Anne. "Exploration du potentiel de données d'observations de terrain pour caractériser ou cartographier des propriétés ou des comportements des sols." Electronic Thesis or Diss., Orléans, 2024. http://www.theses.fr/2024ORLE1049.
Повний текст джерелаАнотація:
Lors de l'élaboration de cartographies des sols ou de la description des sols sur le terrain, de très nombreuses variables sont observées, collectées et enregistrées en base de données. Au fil du temps, ces données sur les sols deviennent disponibles en masse mais certaines n'ont jamais été étudiées dans leur globalité, ni valorisées pour caractériser ou cartographier des propriétés, des fonctionnements ou des comportements des sols. Ces données sont essentiellement qualitatives et souvent ordinales. L'hypothèse de notre travail est qu'il est possible de catégoriser ces variables, de les mettre en relation avec des données quantitatives et de les valoriser en cartographie des sols par modélisation statistique (ou digital soil mapping : DSM).Nous évaluons le bénéfice de l'apport de ces données incertaines en prenant deux exemples fondés sur la texture et la compacité. Nous simulons les conséquences d'utilisation de la texture de terrain sur la calibration et les performances d'une fonction de pédotransfert. Nous montrons également le potentiel important de cette donnée en DSM, tant comme donnée d'entrée, que comme donnée de validation de prédictions de fractions granulométriques. Cette masse de données, de sources parfois hétégogènes, permet également de révéler des structures spatiales non capturées par les variables quantitatives disponibles. Nous utilisons un test de terrain d'estimation de la compacité des sols pour mettre en évidence des clusters de comportement physique qui sont ensuite interprétés et cartographiés à l'échelle nationale.Par ces exemples, nous démontrons que l'utilisation en masse de données qualitatives peut apporter de nouvelles connaissances et être valorisée par l'exploration et le DSM. Nous confirmons également le potentiel de données issues de la télédétection, telle que la spectrogammamétrie aéroportée, comme covariable pour le DSM de la granulométrie des horizons de surface des sols. Nous montrons en particulier qu'il est possible d'extraire des bases de données des informations utilisables et spatialisables à partir de données qualitatives incertaines, sans nécessairement recourir à de nouvelles acquisitions plus coûteusesWhen carrying soil survey or describing soils in the field, a large number of variables are observed, recorded and stored in databases. Over time, this data on soils becomes available overwhelmingly. However, this data has never been studied in its entirety, nor used to characterize or map soil properties, functioning or behavior. These data are essentially qualitative and often ordinal. The hypothesis of our work is that it is possible to categorize these variables, to relate them to quantitative data and to use them in digital soil mapping (DSM).We evaluate the benefit of the contribution of this uncertain data by taking two examples based on soil texture and compactness. We simulate the consequences of using the hand-feel texture on the calibration and performance of a pedotransfer function. We also show the significant potential of this data in DSM of particle-size fractions, both as input data and as validation data. This mass of data, sometimes from heterogeneous sources, also makes it possible to reveal spatial structures not captured by the available quantitative variables. We use a field test to estimate soil compactness to bring out clusters of physical behavior which are then interpreted and mapped on a national scale.Through these examples, we demonstrate that the mass use of qualitative data can provide new knowledge and be enhanced by exploration and the DSM. We also confirm the potential of data from remote sensing, such as airborne spectrogammametry, as a covariate for the DSM of particle-size of topsoil. In particular, we show that it is possible to extract usable and spatially relevant information from uncertain qualitative data, without necessarily resorting to new, more costly acquisitions
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Effenguet, Hervé Crépin. "Écoulements préférentiels dans un sol fin compacté." Vandoeuvre-les-Nancy, INPL, 1998. http://www.theses.fr/1998INPLA94N.
Повний текст джерелаАнотація:
Le développement des écoulements préférentiels dans les milieux poreux constitue un aspect qui doit être maîtrisé pour des études efficaces de caractérisation hydrodynamique de ces matériaux. Dans le but de comprendre ce phénomène dans les sols fins, une étude est réalisée suivant la méthode morphologique sur un sol fin peu plastique, le limon de Jossigny. Pour ce faire, un traceur, le Brillant Bleu, est utilisé. Le matériau pris à différentes teneurs en eau et tailles des mottes est compacté suivant différents modes de compactage (dynamique et semi-statique par couches). L'infiltration, sous différentes pressions hydrauliques, de la solution traçante a permis de noter l'instabilité du front d'humidité dans les éprouvettes de sol reconstituées dynamiquement, tandis que celles issues du compactage semi-statique présentent une répartition et évolution quasi-homogènes des écoulements dans le sol. Le développement des écoulements préférentiels aux faibles et moyennes teneurs en eau dans les éprouvettes reconstituées dynamiquement n'est pas fonction de l'état physique du sol et de la pression hydraulique appliquée, et est exclusivement lié à l'hétérogénéité structurale de tels milieux après compactage. Les données issues du traitement d'images sur ces éprouvettes sont par la suite utilisées pour une tentative de visualisation tridimensionnelle des chemins d'écoulement préférentiel dans ce type d'éprouvettes. La simulation est réalisée grâce au logiciel de modélisation gOcad. Les éprouvettes homogènes issues du compactage semi-statique sont reconstituées suivant une procédure particulière mise au point au cours du présent travail. Cette procédure est issue de la confrontation des résultats issus de l'étude des écoulements préférentiels avec ceux, d'une part, de répartition et d'évolution de la densité dans des éprouvettes dynamiquement reconstituées, et d'autre part, d'évolution de l'indice des vides lors du compactage semi-statique d'une couche épaisse de sol fin. Ces éprouvettes sont par la suite utilisées pour l'étude de l'infiltration dans un sol fin non saturé soumis à l'action d'une légère pression de confinement. Dans le cas du matériau utilisé, et pour les conditions d'essai et la procédure expérimentale considérées, une telle étude s'avère très difficile du fait des effets de paroi (écoulements sol-membrane) et des éventuels changements de la structure du sol dans sa zone humidifiée, sous l'action du confinement agissant simultanément au processus d'infiltration (couplage hydro-mécanique)The development of preferential flow paths in the porous medias constitutes an aspect which must be controlled for effective caracterizations of these materials. Ln order to understand this phenomenon in the fine soils, a study is realised according to the morphological method on a plastic fine soil, the silt of Jossigny. The Blue Brilliance is used to dye the preferential flow paths. The material at various water contents and sizes of the clods is compacted according to various methods of compaction (dynamic and semi-static) by layers. Infiltration of dye under various hydraulic pressures indicates the development of preferential flow paths in the dynamic compacted samples, while those resulting from the semi-static compaction present a quasi-homogeneous distribution and evolution of flow in the soil. The development of the preferential flow paths to low and average water contents in the dynamically compacted samples is not a function of the initial state of the soil and the applied hydraulic pressure. It depends exclusively to structural heterogeneity of such a medium after compaction. The data resulting from the image processing on these samples are used for an attempt at three-dimensional visualization of preferential flow paths. Simulation is realised with gOcad software modelisation. Homogeneous samples resulting trom semi-static compaction are prepared according to a particular proceeding developed during the present work. This proceeding results trom the study of preferential flows and the study of distribution and evolution of density in dynamically compacted samples, and the study of evolution of the void ratio in semi-static compaction of a fine soil. These homogeneous samples are used to study infiltration in a partir fine soil with a slight confining pressure. Ln the case of material used in this study, and for the conditions of test and experimental procedure considered, because of the soil-membrane effects and changes of the structure of the soil under the action of confining during infiltration process (hydro-mechanics coupling) some difficulties have been noted
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Li, Zhong-Sen. "Etudes des propriétés hydromécaniques des sols argileux non saturés proches de la saturation." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2015. http://www.theses.fr/2015ECAP0023/document.
Повний текст джерелаАнотація:
Cette thèse présente un ensemble de résultats expérimentaux sur une argile remaniée non saturée proche de la saturation, dont le degré de saturation est généralement supérieur à 70%.Après une série d’essais de caractérisation physique et mécanique du matériau, plusieurs méthodes expérimentales ont été utilisées pour étudier le comportement et certaines pathologies du sol compacté telles que l’orniérage et le matelassage.Une étude systématique du comportement du sol compacté sur chemins de drainage-humidification dans différents états initiaux a été effectuée, complétée par des mesures de succion par papier filtre et psychromètre. Les essais de porosimétrie par intrusion de mercure ont apporté un éclairage sur la microstructure du sol.La thèse a également permis d’étudier les variations de pression interstitielle du sol compacté sur chemin triaxial non drainé en utilisant la technique de translation d’axes, où quelques améliorations et modifications du montage ont été proposéesThis thesis present an experimental study of an unsaturated clayey soil close to saturation, whose degree of saturation is generally above 70%.After characterizing the physical and mechanical properties of the material, several experimental methods were used to study the behaviour and some pathologies of the compacted soil, such as rutting and quilting.A systematic study of the behaviour of the compacted soil on drying-wetting paths starting from different initial states was carried out, completed by suction measurements using filter-paper and psychrometer. Mercury intrusion porosimetry tests gave an insight of the soil microstructure.The thesis also addressed the question of the pore pressure variations of the compacted soil on undrained triaxial path using the axis-translation technique, where some improvements and modifications of the testing device were proposed
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Pradeep, Krishna. "Caractérisation et modélisation de la variabilité au niveau du dispositif dans les MOSFET FD-SOI avancés." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT020/document.
Повний текст джерелаАнотація:
Selon l’esprit de la “loi de Moore” utilisant des techniques innovantes telles que l’intégration 3D et de nouvelles architectures d’appareils, le marché a également évolué pour commencer à imposer des exigences spécifiques aux composants, comme des appareils à faible consommation et à faible fuite, requis par l’Internet des objets (IoT) applications et périphériques hautes performances demandés par les applications 5-G et les centres de données. Ainsi, le secteur des semi-conducteurs s’est peu à peu laissé guider par les avancées technologiques, mais aussi par les applications.La réduction de la tension d’alimentation est encore plus importante pour les applications à faible puissance, comme dans l’IoT, cela est limité par la variabilité du périphérique. L’abaissement de la tension d’alimentation implique une marge réduite pour que les concepteurs gèrent la variabilité du dispositif. Cela nécessite un accès à des outils améliorés permettant aux concepteurs de prévoir la variabilité des périphériques et d’évaluer son effet sur les performances des leur conception, ainsi que des innovations technologiques permettant de réduire la variabilité des périphériques.Cette thèse se concentre dans la première partie et examine comment la variabilité du dispositif peut être modélisée avec précision et comment sa prévision peut être incluse dans les modèles compacts utilisés par les concepteurs dans leurs simulations SPICE. La thèse analyse d’abord la variabilité du dispositif dans les transistors FD-SOI avancés à l’aide de mesures directes. À l’échelle spatiale, en fonction de la distance entre les deux dispositifs considérés, la variabilité peut être classée en unités de fabrication intra-matrice, inter-matrice, inter-tranche, inter-lot ou même entre différentes usines de fabrication. Par souci de simplicité, toute la variabilité d’une même matrice peut être regroupée en tant que variabilité locale, tandis que d’autres en tant que variabilité globale. Enfin, entre deux dispositifs arbitraires, il y aura des contributions de la variabilité locale et globale, auquel cas il est plus facile de l’appeler la variabilité totale. Des stratégies de mesure dédiées sont développées à l’aide de structures de test spécialisées pour évaluer directement la variabilité à différentes échelles spatiales à l’aide de caractérisations C-V et I-V. L’effet de la variabilité est d’abord analysé sur des facteurs de qualité (FOM) sélectionnés et des paramètres de procédés extraits des courbes C-V et I-V, pour lesquels des méthodologies d’extraction de paramètres sont développées ou des méthodes existantes améliorées. Cette analyse aide à identifier la distribution des paramétres et les corrélations possibles présentes entre les paramètres.Ensuite, nous analysons la variabilité dépendante de la polarisation dans les courbes I-V et C-V. Pour cela, une métrique universelle, qui fonctionne quelle que soit l’échelle spatiale de la variabilité, est definée sur la base de l’analyse des appariement précédemment rapportée pour la variabilité locale. Cette thèse étend également cette approche à la variabilité globale et totale. L’analyse de l’ensemble des courbes permet de ne pas manquer certaines informations critiques dans une plage de polarisation particulière, qui n’apparaissaient pas dans les FOM sélectionnés.Une approche de modélisation satistique est utilisée pour modéliser la variabilité observée et identifier les sources de variations, en termes de sensibilité à chaque source de variabilité, en utilisant un modèle physique compact comme Leti-UTSOI. Le modèle compact est d’abord étalonné sur les courbes C-V et I-V dans différentes conditions de polarisation et géométries. L’analyse des FOM et de leurs corrélations a permis d’identifier les dépendances manquantes dans le modèle compact. Celles-ci ont également été incluses en apportant de petites modifications au modèle compactThe ``Moore's Law'' has defined the advancement of the semi-conductor industry for almost half a century. The device dimensions have reduced with each new technology node, and the design community and the market for the semiconductor have always followed this advancement of the industry and created applications which took better advantage of these new devices. But during the past decade, with the device dimensions approaching the fundamental limits imposed by the materials, the pace of this scaling down of device dimensions has decreased. While the technology struggled to keep alive the spirit of ``Moore's Law'' using innovative techniques like 3-D integration and new device architectures, the market also evolved to start making specific demands on the devices, like low power, low leakage devices demanded by Internet of Things (IoT) applications and high performance devices demanded by 5-G and data centre applications. So the semiconductor industry has slowly moved away from being driven by technology advancement, and rather it is now being driven by applications.Increasing power dissipation is an unavoidable outcome of the scaling process, while also targeting higher frequency applications. Historically, this issue has been handled by replacing the basic transistors (BJTs by MOSFETs), freezing the operation frequency in the system, lowering supply voltage, etc. The reduction of supply voltage is even more important for low power applications like in IoT, but this is limited by the device variability. Lowering the supply voltage implies reduced margin for the designers to handle the device variability. This calls for access to improved tools for the designers to predict the variability in the devices and evaluate its effect on the performance of their design and innovations in technology to reduce the variability in the devices. This thesis concentrates in the first part, and evaluates how the device variability can be accurately modelled and how its prediction can be included in the compact models used by the designers in their SPICE simulations.At first the thesis analyses the device variability in advanced FD-SOI transistors using direct measurements. In the spatial scale, depending on the distance between the two devices being considered, the variability can be classified into intra-die, inter-die, inter-wafer, inter-lot or even between different fabs. For the sake of simplicity all the variability within a single die can be grouped together as local variability, while others as global variability. Finally between two arbitrary device, there will be contributions from both local and global variability, in which case it is easier to term it as the total variability. Dedicated measurement strategies are developed using specialized test structures to directly evaluate the variability in different spatial scales using C-V and I-V characterisations. The effect of variability is first analysed on selected figure of merits (FOMs) and process parameters extracted from the C-V and I-V curves, for which parameter extraction methodologies are developed or existing methods are improved. This analysis helps identify the distribution of the parameters and the possible correlations present between the parameters.A very detailed analysis of the device variability in advanced FD-SOI transistors is undertaken in this thesis and a novel and unique characterisation and modelling methodology for the different types of variability is presented in great detail. The dominant sources of variability in the device behaviour, in terms of C-V and I-V and also in terms of parasitics (like gate leakage current) are identified and quantified. This work paves the way to a greater understanding of the device variability in FD-SOI transistors and can be easily adopted to improve the predictability of the commercial SPICE compact models for device variability
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Yang, Gang. "Compact Photonic Integrated Passive Circuits." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/26958.
Повний текст джерелаАнотація:
Photonic Integrated Circuits (PICs) based on silicon photonics have received great interest due to the low loss caused by the high-refractive-index contrast and the complementary metal-oxide semiconductor compatibility. The need for high-density, high-yield, low-cost, low-power consumption, and large-scale on-chip photonic integration requires the technologies to further minimize the size while exhibiting high performance. Moreover, the fast development and expansion of silicon photonics devices for different applications and functionalities require effective design approaches to optimize the device performance while reducing the design complexity.
In this thesis, several fundamental components for PICs are presented as the building blocks for advanced photonic circuits. To test the effectiveness of the design, Mach–Zehnder interferometers are simulated and fabricated on a Silicon-on-Insulator (SOI) platform, which shows a good agreement between the experimental and simulation results. Moreover, compact vertical grating couplers with broad optical bandwidth are studied. Experimental results show the compact size and the light coupling capabilities.
Multimode Interference (MMI) splitter acts as one critical component in PICs. However, the minimum requirement of mid-to-mid channel spacing to avoid crosstalk limits the MMI size to be further reduced and thus limits the component density in the photonic integration. To solve this problem, a compact SOI MMI power splitter based on optical strip barriers is presented to achieve high crosstalk reduction. Three different MMI power splitters are designed and simulated with an ultra-small device footprint, high uniformity, while maintaining a low insertion loss of 0.4dB.
Inverse design methods with different optimization algorithms are utilized to design compact and high-performance PIC components. Firstly, a sequential least-squares programming algorithm is introduced to inverse design a waveguide crossing. This gradient-based algorithm is suitable for simple structures with fewer parameters, or a good starting point can be obtained from experience or physical theories.
Secondly, a novel dynamic iterative batch optimization method is presented in the thesis to design a high-performance segmented mode expander. In the simulation, the optimized structure achieves a coupling efficiency of 81% for TE polarization at the wavelength of 1550nm. It also shows a simulated transmission loss of lower than -1.137dB within 60nm bandwidth. This approach paves the way for the rapid design of PIC components with a compact footprint. Additionally, a Direct Binary Search (DBS) algorithm is introduced for designing pixel-like structures with binary-value-represented topology patterns, where a 3dB beam splitter is used in the design. DBS algorithm can be utilized to generate a high-quality dataset used for deep learning acceleration methods.
To solve the time-efficiency and non-scalable issues of conventional inverse design methods, a neural network-based inverse design approach is presented and applied on the design of a wavelength demultiplexer structure. The method solves the data domain shift problem that existed in the conventional tandem network architecture and improves the prediction accuracy with a 99% validation accuracy. It also shows high stability and robustness to the quantity and quality of training data. The demonstrated wavelength demultiplexer has an ultra-compact footprint of 2.6×2.6μm2, a high transmission efficiency with a transmission loss of -2dB, and a low crosstalk around -7dB simultaneously.
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Darbandy, Ghader. "Compact modeling of gate tunneling leakage current in advanced nanoscale soi mosfets." Doctoral thesis, Universitat Rovira i Virgili, 2012. http://hdl.handle.net/10803/97215.
Повний текст джерелаАнотація:
En esta tesis se han desarrollado modelos compactos de corriente de fuga por túnel de puerta en SOI MOSFET (de simple y doble puerta) avanzados basados en una aproximación WKB de la probabilidad de túnel. Se han estudiado los materiales dieléctricos high-k más prometedores para los diferentes requisitos de nodos tecnológicos de acuerdo ala hoja de ruta ITRS de miniaturización de dispositivos electrónicos.
Hemos presentado un modelo compacto de particionamiento de la corriente de fuga de puerta para un MOSFET nanométrico de doble puerta (DG MOSFET), utilizando modelos analíticos de la corriente de fuga por el túnel directo de puerta. Se desarrollaron también Los modelos analíticos dependientes de la temperatura de la corriente de túnel en la región de inversión y de la corriente túnel asistido por trampas en régimen subumbral.
Finalmente, se desarrolló una técnica de extracción automática de parámetros de nuestro modelo compacto en DG MOSFET incluyendo efectos de canal corto. La corriente de la puerta por túnel directo y asistido por trampas modelada mediante los parámetros extraídos se verificó exitosamente mediante comparación con medidas experimentales.
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Hoang, Ngoc Lan. "Etudes des propriétés hydromécaniques d’un sable limoneux : de la saturation partielle à la saturation complète." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSET005/document.
Повний текст джерелаАнотація:
Cette thèse concerne la caractérisation expérimentale d’un sable limoneux provenant du barrage de Livet – Gavet (38) dans le cadre du projet ANR TerreDurable avec plusieurs objectifs : 1- Caractériser au travers d’essais de laboratoire le comportement hydromécanique d’un sable fin limoneux (sol A1 dans la classification GTR) en fonction de son état de saturation. Lors de cette étude, un accent particulier est porté sur la caractérisation de ce comportement dans le domaine proche de la saturation. 2- Interpréter le comportement hydrique du matériau sur chemin de drainage – imbibition en relation avec l’analyse de sa microstructure. 3- Fournir d’un point de vue général une base de données et d’analyses exhaustive permettant le développement et la calibration de modèles de comportement des sols fins proches de la saturation, en particulier en considérant des chemins de chargement hydromécanique complexes. Pour l’ensemble de cette étude, le matériau est considéré sous deux états : soit à l’état de pâte (matériau normalement consolidé) préparée à une teneur en eau proche de la limite de liquidité, soit sous forme compactée (matériau sur-consolidé) à différentes énergies de compactage et différentes teneurs en eau initialesThis thesis concerns the experimental characterization of a silty sand from the Livet - Gavet dam (38) as part of the ANR TerreDurable project, for following objectives: 1- Through laboratory tests, characterize the hydro-mechanical behaviour of a fine silty sand (Type A1 in the GTR classification) according to its saturation state. In this study, particular emphasis is placed on the characterization of this behaviour in the near-saturated domain. 2- Interpret the water behaviour of material on the drainage - imbibition cycles, in relation to the analysis of its microstructure. 3- From a general point of view, provide a comprehensive database and analysis allowing the development and calibration of models of near-saturated fine soil's behaviour, in particular, by considering complex hydro-mechanical loading paths. For all tests in this study, the material is considered in two states: either in the state of paste (normally consolidated material) prepared at water content close to the limit of liquidity, or in compacted state (over consolidated material) at different compaction energies and different initial water contents
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Diagne, Birahim. "Étude et modélisation compacte d'un transistor MOS SOI double-grille dédié à la conception." Phd thesis, Université Louis Pasteur - Strasbourg I, 2007. http://tel.archives-ouvertes.fr/tel-00206167.
Повний текст джерелаАнотація:
Nous proposons un modèle compact du transistor MOS double-grille silicium sur isolant (SOI) en mode de fonctionnement symétrique. Le modèle est basé sur le formalisme EKV et offre les caractéristiques suivantes : une expression analytique simple décrivant le comportement statique et dynamique du dispositif, des relations « directes » entre charges–tensions et tensions–courant, une méthode de calcul numérique robuste et rapide, une implémentation aisée du modèle dans un langage de haut niveau tel que VHDL-AMS permettant ainsi une simulation rapide et précise des caractéristiques électriques.Le modèle prend en compte non seulement les effets de petites géométries tels que l'abaissement de la barrière de potentiel induit par le drain, le partage de charge, la dégradation de la pente sous le seuil ainsi que la réduction de la mobilité des porteurs, mais également les effets dynamiques extrinsèques.
Il a été validé pour des dispositifs de longueur de canal de 60nm. Sa validation a été effectuée par comparaison de ses résultats avec ceux obtenus sur le simulateur de composants Atlas/SILVACO.
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Diagne, Birahim. "Etude et modélisation compacte d'un transistor MOS SOI double-grille dédié à la conception." Université Louis Pasteur (Strasbourg) (1971-2008), 2007. https://publication-theses.unistra.fr/public/theses_doctorat/2007/DIAGNE_Birahim_2007.pdf.
Повний текст джерелаАнотація:
Nous proposons un modèle compact du transistor MOS double-grille silicium sur isolant (SOI) en mode de fonctionnement symétrique. Le modèle est basé sur le formalisme EKV et offre les caractéristiques suivantes : une expression analytique simple décrivant le comportement statique et dynamique du dispositif, des relations "directes" entre charges-tensions et tensions-courant, une méthode de calcul numérique robuste et rapide, une implémentation aisée du modèle dans un langage de haut niveau tel que VHDL-AMS permettant ainsi une simulation rapide et précise des caractéristiques électriques. Le modèle prend en compte non seulement les effets de petites géométries tels que l'abaissement de la barrière de potentiel induit par le drain; le partage de charge, la dégradation de la pente sous le seuil ainsi que la réduction de la mobilité des porteurs, mais également les effets dynamiques extrinsèques. Il a été validé pour des dispositifs de longueur de canal de 60nm. Savalidation a été effectuée par comparaison de ses résultats avec ceux obtenus sur le simulateur de composants Atlas/SILVACO.
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Altındiş, Mustafa Güden Mustafa. "CaP coating of porous sintered Ti6Al4V powder compacts using biomimetic and sol-gel methods." [s.l.]: [s.n.], 2006. http://library.iyte.edu.tr/tezler/master/malzemebilimivemuh/T000544.pdf.
Повний текст джерелаКниги з теми "Soil compacity"
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Bingner, R. L. COMPACT: A reclamation soil compaction model. S.l: s.n, 1992.
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J, De Young R., Elsayid-Ele Hani, and Langley Research Center, eds. Compact ozone differential absorption lidar (DIAL) transmitter using soild-state dye polymers. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 2001.
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The Rough Guide to Soul 100 Essential CDs. Rough Guides, 2000.
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Tee, Ralph. The Best of Soul: The Essential Cd Guide (The Essential CD Guides). Collins Pub San Francisco, 1993.
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Tee, Ralph. The Best of Soul: The Essential Cd Guide (The Essential CD Guides). Collins Pub San Francisco, 1993.
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Bruegmann, Robert. Sprawl: A Compact History. University of Chicago Press, 2010.
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Bruegmann, Robert. Sprawl: A Compact History. University Of Chicago Press, 2005.
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Bruegmann, Robert. Sprawl: A Compact History. University Of Chicago Press, 2006.
Знайти повний текст джерелаЧастини книг з теми "Soil compacity"
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Wu, Weimin, Wei Yao, and Gennady Gildenblat. "PSP-SOI: A Surface-Potential-Based Compact Model of SOI MOSFETs." In Compact Modeling, 41–74. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8614-3_2.
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Ghosh, Souvik, Tuffail Dar, Charusluk Viphavakit, Chao Pan, N. Kejalakshmy, and B. M. A. Rahman. "Compact Photonic SOI Sensors." In Computational Photonic Sensors, 343–83. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-76556-3_14.
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Morthier, Geert, Gunther Roelkens, and Dries Van Thourhout. "III-V Compact Lasers Integrated onto Silicon (SOI)." In Compact Semiconductor Lasers, 195–230. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527655342.ch5.
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Boeve, Marlon. "Environmental Law Tools for the Idea of a Compact City. Learning from the Dutch Case." In International Yearbook of Soil Law and Policy 2018, 113–29. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-00758-4_5.
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Amoozegar, A. "Compact Constant Head Permeameter: A Convenient Device for Measuring Hydraulic Conductivity." In Advances in Measurement of Soil Physical Properties: Bringing Theory into Practice, 31–42. Madison, WI, USA: Soil Science Society of America, 2012. http://dx.doi.org/10.2136/sssaspecpub30.c3.
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Morleghem, Daniel. "Les tombes rupestres de Touraine : caractérisation morphologique, technologique, topographique et chronologique." In Rencontre autour des typo-chronologies des tombes à inhumation, 353–58. Tours: Fédération pour l’édition de la Revue archéologique du Centre de la France, 2022. http://dx.doi.org/10.4000/12phr.
Повний текст джерелаАнотація:
Les tombes rupestres de Touraine peuvent être définies comme des fosses creusées sur toute leur hauteur dans un substrat rocheux homogène et compact – en général une roche calcaire dure –, le plus souvent depuis le sol de circulation, et dont la réalisation a nécessité l’usage d’un outillage et d’un savoir-faire similaires à ceux de la taille de pierre. Mais, dans quelle mesure la tombe rupestre peut-elle être considérée, en Touraine, comme un type de tombe spécifique ?
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Ernst, T., A. Vandooren, S. Cristoloveanu, T. E. Rudenko, and J. P. Colinge. "Recombination Current in Fully-Depleted SOI DIODES: Compact Model and Lifetime Extraction." In Perspectives, Science and Technologies for Novel Silicon on Insulator Devices, 213–16. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4261-8_20.
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Mishra, Sikha, Soumya S. Mohanty, Subhashree Bhol, and Guru Prasad Mishra. "A Compact Analytical Model and Electrostatic Performance Investigation of Multilayer Groove Gate SOI-MOSFET." In ICICCT 2019 – System Reliability, Quality Control, Safety, Maintenance and Management, 753–60. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-8461-5_86.
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Raach, Fatma, and Hiba Sha’ath. "Tunisia-EU Cooperation in Migration Management: From Mobility Partnership to Containment." In International Perspectives on Migration, 219–32. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-74866-0_13.
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AbstractThis chapter examines select political, legal, and financial instruments regarding asylum, protection, and mobility between Tunisia and the EU. We have assessed the effectiveness, fairness, and consistency of these instruments, to determine whether they have been successful in achieving their stated aims, have been designed and implemented with accountability mechanisms, and have been aligned with international and regional human rights standards. The chapter concludes that while some of the instruments have achieved their stated results of building the Tunisian state’s capacity to host refugees, they have been lacking in transparency, accountability mechanisms, and compatibility with international and regional human rights laws. With the focus predominantly having been on the containment of refugees to Tunisia through emphasis on border protection programs and readmission agreements, the instruments’ alignment with the Global Compact for Refugees is limited, as there is far more pressure exerted on Tunisia to host a growing number of third country nationals and prevent their onward movement to Europe, with few other initiatives aimed at easing this burden. While the continued absence of asylum legislation has been a barrier to upholding refugees’ rights in the country, we argue that Tunisian officials’ refusal to pass national asylum legislation has been their way of resisting EU pressure to become a safe third country of asylum, as they fear this will pave the way to other EU actions of deporting third country nationals to Tunisia, and to set up offshore asylum processing centres on Tunisian soil. The Chapter critiques the EU’s approach in its mobility partnership with Tunisia to date due to its outsized focus on security and insufficient attention to the needs and perceptions of Tunisian counterparts.
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Kim, Seong-Dong, Jeffrey B. Johnson, Jun Yuan, and Jason C. S. Woo. "Optimization of Recessed and Elevated Silicide Source/Drain Contact Structure Using Physical Compact Resistance Modeling and Simulation in Ultra-Thin Body SOI MOSFETs." In Simulation of Semiconductor Processes and Devices 2004, 247–50. Vienna: Springer Vienna, 2004. http://dx.doi.org/10.1007/978-3-7091-0624-2_57.
Повний текст джерелаТези доповідей конференцій з теми "Soil compacity"
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McIlwain, Sam, Bruce Hamersley, William Wu, and Tian Wang. "Viaduct Solutions for Unstable Slopes in the Kicking Horse Canyon." In IABSE Congress, San José 2024: Beyond Structural Engineering in a Changing World, 533–41. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2024. https://doi.org/10.2749/sanjose.2024.0533.
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<p>This paper presents an innovative viaduct solution using accelerated bridge construction techniques crossing a series of unstable slopes, active landslides, and avalanche and rock fall paths along a treacherous highway section of the Kicking Horse Canyon Phase 4 project in British Columbia, Canada. The utilization of compact precast concrete components significantly minimized on-site labour requirements, improved the constructability, and reduced the construction schedule and cost. Approximately 1.8 km of viaduct structures were designed to span the unstable soils. Significant loads from avalanches and landslides were imposed on the viaducts. The piled foundations were designed to resist the loads as soil failed around the piles during a landslide, rather than fully stabilize the slopes. A unique “drift-link” detail connected the piles to the pier caps to accommodate thermal movement, as well as provide load-sharing between piles for lateral loads.</p>
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Di Martino, Gerardo, Alessio Di Simone, and Antonio Iodice. "Polarimetric Two-Scale Model for Soil Moisture Estimation from Hybrid Compact Polarimetry SAR Data." In IGARSS 2024 - 2024 IEEE International Geoscience and Remote Sensing Symposium, 4457–60. IEEE, 2024. http://dx.doi.org/10.1109/igarss53475.2024.10642885.
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Liu, XinjieJeff, David Verity, Antony Sou, and Thomas Gneiting. "Application of SOI Compact Model to a-IGZO Technology." In 2024 IEEE International Flexible Electronics Technology Conference (IFETC), 1–3. IEEE, 2024. https://doi.org/10.1109/ifetc61155.2024.10771856.
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Cheng, Weiqing, Xiao Sun, Shengwei Ye, Bocheng Yuan, John H. Marsh, and Lianping Hou. "Subwavelength Grating Cascaded Microring Resonator Biochemical Sensors with Record-High Sensitivity." In CLEO: Science and Innovations, SF2J.8. Washington, D.C.: Optica Publishing Group, 2024. http://dx.doi.org/10.1364/cleo_si.2024.sf2j.8.
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A compact SOI-based subwavelength grating cascaded microring resonator is demonstrated with a record-high sensitivity of 810 nm/RIU and a limit of detection of 2.04×10-5 RIU. The measured concentration sensitivity is 1430 pm/%.
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Crismaru, Valentin. "Evolutia structurii semanaturilor cu culturi agricole de câmp în regiunea de dezvoltare centru." In Impactul antropic asupra calitatii mediului. Institute of Ecology and Geography, Republic of Moldova, 2019. http://dx.doi.org/10.53380/9789975330800.31.
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This paper present data regarding evolution of surface of the technical, hoeing and compact crops in the Development Region Central. Due to the growing of the technical and hoeing crops situation worsened considerably as result negative impact over the soil of Region Central. The impact of agricultural activities and pressure of various factors, also led to decrease of soil quality and the growth the areas of soils eroded.
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Lundberg, Anders Beijer, Fredrik Resare, and Gary Axelsson. "Numerical Modelling of Inclined Piles in Settling Soil." In The 13th Baltic Sea Region Geotechnical Conference. Vilnius Gediminas Technical University, 2016. http://dx.doi.org/10.3846/13bsgc.2016.019.
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The allowable load for slender end-bearing piles in soft soils driven or drilled to compact till or rock frequently depends on the structural capacity of the pile. Pile groups consisting of such slender preceast concrete or steel piles often include inclined piles, since such small-diameter piles have a limited horizontal bearing capacity. Inclined piles placed in settling soil are subjected to a lateral force, which reduces the pile structural capacity. The simplified beam-spring design methods normally used to predict the impact on the structural capacity of inclined piles in settling soil are currently very crude because of the simplified description of the real pile and soil. On the other hand, the possibility to accurately calculate settlements in soft soil is highly developed, and it is possible to include creep effects in routine settlement calculations. There is currently no direct link between the advanced settlement analysis and the crude beam-spring idealization of inclined piles in settling soil. A full numerical model containing both the pile soilstructure interaction and the settlement process is very time-consuming to run and associated with mesh convergence and contact formulation problems. Herein a suitable modelling idealization of the settling soil is discussed, in which a settlement distribution from an advanced FEM-analysis is adapted to a simplified FEM or beam spring analysis suitable for practical design. The calculation method is compared to field measurements, and is shown to compare well with the field case. A strategy to adapt the settlement profile to model calculation of inclined piles is discussed.
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Bulimaga, Constantin, Aureliu Burghelea, Corina Certan, Maria Rusu, and Nicolae Bodrug. "Procesul de evoluare a regosolului pe suprafața haldei de steril în cariera de calcar lafarge ciment (Moldova) s.a. din Rezina." In Provocări şi tendinţe actuale în cercetarea componentelor naturale şi socio-economice ale ecosistemelor urbane şi rurale. Institute of Ecology and Geography, Republic of Moldova, 2020. http://dx.doi.org/10.53380/9789975891608.13.
Повний текст джерелаАнотація:
Soil profiles made on the platform with recent deposits under multiannual plants and under trees have shown that they represent regosols (in fact, conventional, because they were recently deposited and flattened (a. 2017) and are composed of fossil soils and unconsolidated rocks) luto-clay with ocher horizont. Layer I (0-2 cm) - the litter is well pronounced, dark brown, resinous, clay-clay, dusty, the structure of the fossil soil was preserved, on the basis of which it formed, loosened, porous, the passage between the underlying clear horizon after compactness. Layer II (2-10 cm) - represents recent deposits, formed on the basis of the fossil soil, reavane, luto-clay, prismatic structure slightly pronounced, more compact than the overlying layer. Layer III (10-38 cm) - recent deposits, formed on the basis of the fossil soil, differs from the overlying layer with a high degree of settling. The fourth layer (38-60 cm) - recent deposits, formed on the basis of the fossil soil, differs from the overlying layer with a high degree of settling. The humus content in the beds under multi-annual plants and under the trees indicated that the humus content in the litter under the perennial plants is 5 times higher than in the litter under the trees, which is explained by the amount of high organic matter which is generated by species of perennial plants rather than trees, which ensures the generation of higher humus content (organic matter).
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Chen, Weixing, and Robert Sutherby. "Environmental Effect of Crack Growth Rate of Pipeline Steel in Near-Neutral pH Soil Environments." In 2004 International Pipeline Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ipc2004-0449.
Повний текст джерелаАнотація:
The laboratory work reported here was initiated to determine whether different soils can be shown to give rise to different growth rate for a given pipeline steel. Two soil synthetic environments with different near neutral pH value were designed based on various soil chemistries collected near the pipeline in the field where near-neutral pH SCC was found. The crack growth behavior in both the environments were determined using compact tension specimen. The crack growth rate was in situ monitored by the potential drop system. It was found that soil chemistry has a profound effect on crack growth rate. Although it is insensitive to the soil chemistry and cyclic frequency, the crack growth rate in the high ΔK regime has been significantly enhanced in comparison with that in air. In the low ΔK regime, the growth rate is shown to have minor dependence on ΔK value but strong dependence on the testing environments. The observed crack growth behavior in different ΔK regimes and environments was related to the crack tip sharpness and crack crevice wideness as a result of corrosion and room temperature creep deformation. Soil solutions with low general corrosion rate are associated with a blunt crack tip and wide crack crevice, which would result in lower stress intensity at the crack tip and weaker crack closure effect, respectively. Similarly, a loading wave allowing shorter creep time on a given volume of material at the crack tip at high loading stress tends to produce a sharper crack tip and narrow crack crevice. These two factors have opposite effect on crack growth rate, and the observed crack growth rate reflects the combined effect of these two opposite factors.
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A Hamed, Hesham, Savas Kaya, and Janusz Starzyk. "Compact Tunable Current-Mode Analog Circuits Using DGMOSFETs." In 2006 IEEE international SOI. IEEE, 2006. http://dx.doi.org/10.1109/soi.2006.284437.
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Ashigaki, K., D. Hagiwara, K. Negishi, S. Yoshihama, M. Ueda, Y. Yasuyuki, and T. Nakamura. "Soil Transport Experiment by Peristaltic Transport Machine for Compact Automatic Transportation System of Excavated Soil." In 2018 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM). IEEE, 2018. http://dx.doi.org/10.1109/aim.2018.8452425.
Повний текст джерелаЗвіти організацій з теми "Soil compacity"
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Li, J., S. Wang, and H. A. J. Russell. Downscaling SMAP soil moisture using radarsat constellation mission (RCM) compact polarimetric SAR data: A case study in southern Ontario. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2020. http://dx.doi.org/10.4095/321102.
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Compact Subsurface Soil Investigation System. Innovative Technology Summary Report. Office of Scientific and Technical Information (OSTI), December 1998. http://dx.doi.org/10.2172/7504.
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