139 research outputs found

    Negative correlation between soil salinity and soil organic carbon variability

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    We gratefully acknowledge The Climate and Environmental Research Institute NILU for providing the computational and storage resources and facilities essential for conducting this research (project NILU #B106057). Additional funding through the project SIS-EO (NILU #B121004) is gratefully acknowledged. N.S. would like to acknowledge funding for AI4SoilHealth project from the European Union’s Horizon Europe research and innovation programme under grant agreement No.101086179.Peer reviewe

    MULTIPLE INTELLIGENCES AS PREDICTORS OF READING COMPREHENSION AND VOCABULARY KNOWLEDGE

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    Abstract: The present study was conducted to investigate types of Multiple Intelligences as predictors of reading comprehension and vocabulary knowledge. To meet this objective, a 60-item TOEFL test and a 90-item multiple intelligences questionnaire were distributed among 240 male and female Iranians studying English at Qazali and Parsian Universities in Qazvin. Data were analyzed using a multiple regression procedure. The result of the data analysis indicated that musical, interpersonal, kinesthetic, and logical intelligences were predicators of reading comprehension. Moreover, musical, verbal, visual, kinesthetic and natural intelligences made significant contributions to predicting vocabulary knowledge.  Key words: Multiple intelligences, reading comprehension, vocabulary knowledge

    Fundamental investigation of foam flow in a liquid-filled Hele-Shaw cell

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    The relative immobility of foam in porous media suppresses the formation of fingers during oil displacement leading to a more stable displacement which is desired in various processes such as Enhanced Oil Recovery (EOR) or soil remediation practices. Various parameters may influence the efficiency of foam-assisted oil displacement such as properties of oil, the permeability and heterogeneity of the porous medium and physical and chemical characteristics of foam. In the present work, we have conducted a comprehensive series of experiments using customised Hele-Shaw cells filled with either water or oil to describe the effects of foam quality, permeability of the cell as well as the injection rate on the apparent viscosity of foam which is required to investigate foam displacement. Our results reveal the significant impact of foam texture and bubble size on the foam apparent viscosity. Foams with smaller bubble sizes have a higher apparent viscosity. This statement only applies (strictly speaking) when the foam quality is constant. However, wet foams with smaller bubbles may have lower apparent viscosity compared to dry foams with larger bubbles. Furthermore, our results show the occurrence of more stable foam-water fronts as foam quality decreases. Besides, the complexity of oil displacement by foam as well as its destabilizing effects on foam displacement has been discussed. Our results extend the physical understanding of foam-assisted liquid displacement in Hele-Shaw cell which is a step to required to understanding the foam flow behaviour in more complex systems such as porous media

    Foam improved oil recovery : modelling the effect of an increase in injection pressure

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    A model, called pressure-driven growth, is analysed for propagation of a foam front through an oil reservoir during improved oil recovery using foam. Numerical simulations of the model predict, not only the distance over which the foam front propagates, but also the instantaneous front shape. A particular case is studied here in which the pressure used to drive the foam along is suddenly increased at a certain point in time. This transiently produces a concave front shape (seen from the domain ahead of the front): such concavities are known to be delicate to handle numerically. As time proceeds however, the front evolves back towards a convex shape, and this can be predicted by a long-time asymptotic analysis of the model. The increase in driving pressure is shown to be beneficial to the improved oil recovery process, because it gives a more uniform sweep of the oil reservoir by the foam

    A Novel Analytical Solution to Steady-State Evaporation from Soil and Film Region Thickness

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    Evaporation from soil and other porous media constitutes a significant source of water loss affecting global water balance and energy exchange between land and atmosphere. The presence of a shallow water table can lead to sustained water loss that is dependent on porous media hydraulic properties and water table depth among other factors. In this paper, an exact analytical solution to steady state evaporation from porous media is developed using the Brooks-Corey hydraulic conductivity model. The solution is presented in terms of a set of infinite series. An advantage of this solution compared to previous derivations is that the infinite series can be very closely approximated using a closed-form solution (i.e., excluding integrals or series). The novel solution shows excellent agreement with the exact solution for a broad range of soil texture from sand to clay. The applicability of the solution to predict the location of the drying front was also verified using experimental data taken from the literature. The solution may be used for directly modeling steady state evaporation or for inverse determination of the Brooks-Corey hydraulic parameters

    Modelling foam improved oil recovery within a heterogeneous reservoir

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    The displacement of foam within a heterogeneous reservoir during foam improved oil recovery is described with the pressure-driven growth model. The pressure-driven growth model has previously been used to study foam motion for homogeneous cases. Here the foam model is modified in such a way that it includes terms for variable permeability. This model gives the evolution of the foam motion over time and the shape of the foam front, a wet foam zone between liquid-filled and gas-filled zones. The foam front shape for a heterogeneous or stratified reservoir develops concave and convex regions. For shapes such as these, the numerical solution of pressure-driven growth requires special numerical techniques, particularly in the case where concavities arise. We also present some analysis of the level of heterogeneity and how it affects the displacement, the shape of the front developing a set of concave corners. In addition to this we consider a heterogeneous and isotropic reservoir, in which case the foam front can sustain concavities, without these concavities having the same tendency to develop into corners

    Global predictions of primary soil salinization under changing climate in the 21st century

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    From Springer Nature via Jisc Publications RouterHistory: received 2020-11-01, accepted 2021-10-28, registration 2021-10-29, pub-electronic 2021-11-18, online 2021-11-18, collection 2021-12Publication status: PublishedFunder: RCUK | Engineering and Physical Sciences Research Council (EPSRC); doi: https://doi.org/10.13039/501100000266; Grant(s): EP/K011820/1Funder: 1- Presidential Doctoral Scholarship Award at The University of Manchester and 2- Institute of Geo-Hydroinformatics at Hamburg University of TechnologyAbstract: Soil salinization has become one of the major environmental and socioeconomic issues globally and this is expected to be exacerbated further with projected climatic change. Determining how climate change influences the dynamics of naturally-occurring soil salinization has scarcely been addressed due to highly complex processes influencing salinization. This paper sets out to address this long-standing challenge by developing data-driven models capable of predicting primary (naturally-occurring) soil salinity and its variations in the world’s drylands up to the year 2100 under changing climate. Analysis of the future predictions made here identifies the dryland areas of South America, southern and western Australia, Mexico, southwest United States, and South Africa as the salinization hotspots. Conversely, we project a decrease in the soil salinity of the drylands in the northwest United States, the Horn of Africa, Eastern Europe, Turkmenistan, and west Kazakhstan in response to climate change over the same period
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