Articoli di riviste: "Shallow water systems"

1

Clarkson, Peter A., e Thomas J. Priestley. "Shallow Water Wave Systems". Studies in Applied Mathematics 101, n. 4 (novembre 1998): 389–432. http://dx.doi.org/10.1111/1467-9590.00099.

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Saxena, Atanu Basu, N. K. "A Review of Shallow-Water Mapping Systems". Marine Geodesy 22, n. 4 (ottobre 1999): 249–57. http://dx.doi.org/10.1080/014904199273380.

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3

Browning, G. L., e H.-O. Kreiss. "Reduced Systems for the Shallow Water Equations". Journal of the Atmospheric Sciences 44, n. 19 (ottobre 1987): 2813–22. http://dx.doi.org/10.1175/1520-0469(1987)044<2813:rsftsw>2.0.co;2.

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4

Illes, Ladislav, Tomas Kalina, Martin Jurkovic e Vladimir Luptak. "Distributed Propulsion Systems for Shallow Draft Vessels". Journal of Marine Science and Engineering 8, n. 9 (29 agosto 2020): 667. http://dx.doi.org/10.3390/jmse8090667.

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The aim of this study was to investigate the impact of distributed propulsion systems used on inland and coastal navigation in shallow water. Five layouts were assessed by computational fluid dynamics (CFD) simulation. The hull/propulsion layout cases have been analyzed for discrete flow speed values in the range 0–6 m/s. All cases have been examined under restricted draft conditions in shallow water with a minimum of 0.3 m under keel clearance (UKC) and under unrestricted draft conditions in deep water. The results show that distributed propulsion consisting of 6 or 8 (in some cases, even more) units produces noticeable higher thrust effects in shallow water than the traditional layout. Under restricted conditions, the thrust increase between two distributed layouts with different numbers of propulsors is higher, in contrast to deep water, where differences in performance are not so significant.

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Korpusov, M. O., e E. V. Yushkov. "Solution blowup for systems of shallow-water equations". Theoretical and Mathematical Physics 177, n. 2 (novembre 2013): 1505–14. http://dx.doi.org/10.1007/s11232-013-0119-9.

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6

Sangapate, P. "Adaptive Control and Synchronization of the Shallow Water Model". Mathematical Problems in Engineering 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/529251.

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The shallow water model is one of the important models in dynamical systems. This paper investigates the adaptive chaos control and synchronization of the shallow water model. First, adaptive control laws are designed to stabilize the shallow water model. Then adaptive control laws are derived to chaos synchronization of the shallow water model. The sufficient conditions for the adaptive control and synchronization have been analyzed theoretically, and the results are proved using a Barbalat's Lemma.

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7

Hu, Qiaoyi, Zhixin Wu e Yumei Sun. "Liouville theorems for periodic two-component shallow water systems". Discrete & Continuous Dynamical Systems - A 38, n. 6 (2018): 3085–97. http://dx.doi.org/10.3934/dcds.2018134.

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8

Branco, Brett, Thomas Torgersen, John R. Bean, Gary Grenier e Dennis Arbige. "A new water column profiler for shallow aquatic systems". Limnology and Oceanography: Methods 3, n. 3 (marzo 2005): 190–202. http://dx.doi.org/10.4319/lom.2005.3.190.

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Didenkulova, Ira, e Efim Pelinovsky. "Rogue waves in nonlinear hyperbolic systems (shallow-water framework)". Nonlinearity 24, n. 3 (25 gennaio 2011): R1—R18. http://dx.doi.org/10.1088/0951-7715/24/3/r01.

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10

Pivnev, P. P., A. P. Voloshchenko e S. P. Tarasov. "Monitoring of Bioresources in Shallow Water by Parametric Systems". IOP Conference Series: Earth and Environmental Science 459 (15 aprile 2020): 042089. http://dx.doi.org/10.1088/1755-1315/459/4/042089.

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11

Gonzalo, Fernando del Ama, e Juan A. Hernandez Ramos. "Testing of Water Flow Glazing in Shallow Geothermal Systems". Procedia Engineering 161 (2016): 887–91. http://dx.doi.org/10.1016/j.proeng.2016.08.742.

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12

Yaşar, Emrullah, e Teoman Özer. "Conservation laws for one-layer shallow water wave systems". Nonlinear Analysis: Real World Applications 11, n. 2 (aprile 2010): 838–48. http://dx.doi.org/10.1016/j.nonrwa.2009.01.028.

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13

Lastra, Miguel, José M. Mantas, Carlos Ureña, Manuel J. Castro e José A. García-Rodríguez. "Simulation of shallow-water systems using graphics processing units". Mathematics and Computers in Simulation 80, n. 3 (novembre 2009): 598–618. http://dx.doi.org/10.1016/j.matcom.2009.09.012.

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14

Zahoor, F., M. A. Malik, R. Anser, M. Shehzad, A. Saleem, M. Anser, M. H. Siddiqui, K. Mubeen e S. H. Raza. "Water Use Efficiency and Rain Water Productivity of Wheat under Various Tillage-Glyphosate Interactive Systems". Cercetari Agronomice in Moldova 48, n. 1 (1 marzo 2015): 25–36. http://dx.doi.org/10.1515/cerce-2015-0014.

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Abstract Rainfed wheat is generally grown in rotation with summer fallow in medium to high rainfall zone of Pothwar plateau of Pakistan. The present study was, therefore, conducted to investigate the impact of shallow and deep tillage practices, with and without herbicide (glyphosate) application, on moisture conservation and subsequent wheat yields. The study also aimed to examine the feasibility of substituting intensive shallow tillage with single application of glyphosate. The experiment was laid out in randomized complete block design with three replicates and net plot size of 14 m x 10 m, during 2007 and 2008 at two locations i.e high and medium rainfall. Wheat cultivar “GA-2002” was planted as a test crop. The data showed the superiority of conservation tillage in terms of conservation of moisture and increasing grain yields. Results also elaborated that tillage cannot be completely eliminated for profitable fallow management. However, deep ploughing with moldboard followed by single application of glyphosate proved potential option for substituting shallow tillage carried out during summer (kharif). The additional benefits under this tillage system included saving in fuel, labour and lower depreciation and maintenance costs for tillage machinery in addition to unquantifiable environmental benefits.

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15

Zhang, Zhujun, Wei Fan, Weicheng Bao, Chen-Tung A. Chen, Shuo Liu e Yong Cai. "Recent Developments of Exploration and Detection of Shallow-Water Hydrothermal Systems". Sustainability 12, n. 21 (2 novembre 2020): 9109. http://dx.doi.org/10.3390/su12219109.

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A hydrothermal vent system is one of the most unique marine environments on Earth. The cycling hydrothermal fluid hosts favorable conditions for unique life forms and novel mineralization mechanisms, which have attracted the interests of researchers in fields of biological, chemical and geological studies. Shallow-water hydrothermal vents located in coastal areas are suitable for hydrothermal studies due to their close relationship with human activities. This paper presents a summary of the developments in exploration and detection methods for shallow-water hydrothermal systems. Mapping and measuring approaches of vents, together with newly developed equipment, including sensors, measuring systems and water samplers, are included. These techniques provide scientists with improved accuracy, efficiency or even extended data types while studying shallow-water hydrothermal systems. Further development of these techniques may provide new potential for hydrothermal studies and relevant studies in fields of geology, origins of life and astrobiology.

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16

Hoekstra, N. J., J. A. Finn e A. Lüscher. "The effect of drought and interspecific interactions on the depth of water uptake in deep- and shallow-rooting grassland species as determined by δ18O natural abundance". Biogeosciences Discussions 11, n. 3 (15 marzo 2014): 4151–86. http://dx.doi.org/10.5194/bgd-11-4151-2014.

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Abstract. Increased incidence of weather drought, as predicted under climate change, has the potential to negatively affect grassland production. Compared to monocultures, vertical belowground niche complementarity between shallow- and deep-rooting species may be an important mechanism resulting in higher yields and higher resistance to drought in grassland mixtures. However, very little is known about the belowground responses in grassland systems and increased insight into these processes may yield important information both to predict the effect of future climate change and better design agricultural systems to cope with this. This study assessed the effect of a 10-week experimental summer drought on the depth of water uptake of two shallow-rooting species (Lolium perenne L. and Trifolium repens L.) and two deep-rooting species (Chicorium intybus L. and Trifolium pratense L.) in grassland monocultures and four-species-mixtures by using the natural abundance δ18O isotope method. We tested the following hypotheses: (1) drought results in a shift of water uptake to deeper soil layers, (2) deep-rooting species take up a higher proportion of water from deeper soil layers relative to shallow-rooting species, (3) as a result of interspecific interactions in mixtures, the water uptake of shallow-rooting species become shallower when grown together with deep-rooting species and vice versa, resulting in reduced niche overlap. The natural abundance δ18O technique provided novel insights into the depth of water uptake of deep- and shallow- rooting grassland species and revealed large shifts in response to drought and interspecific interactions. Compared to control conditions, drought reduced the proportional water uptake from 0–10 cm soil depth (PCWU0–10) of L. perenne, T. repens and C. intybus in monocultures by on average 54%. In contrast, the PCWU0–10 of T. pratense in monoculture increased by 44%, and only when grown in mixture did the PCWU0–10 of T. pratense decrease under drought conditions. In line with hypothesis 2, in monoculture, the PCWU0–10 of shallow-rooting species L. perenne and T. repens was 0.53 averaged over the two drought treatments, compared to 0.16 for the deep-rooting C. intybus. Surprisingly, in monoculture, water uptake by T. pratense was shallower than for the shallow-rooting species (PCWU0–10 = 0.68). Interspecific interactions in mixtures resulted in a shift in the depth of water uptake by the different species. As hypothesised, the shallow-rooting species L. perenne and T. repens tended to become shallower, and the deep-rooting T. pratense made a dramatic shift to deeper soil layers (reduction in PCWU0–10 of 58% on average) in mixture compared to monoculture. However, these shifts did not result in a reduction in the proportional similarity of the proportional water uptake from different soil depth intervals (niche overlap) in mixtures compared to monocultures. There was no clear link between interspecific differences in depth of water uptake and drought resistance. C. intybus, the species with water uptake from the deepest soil layers was one of the species most affected by drought. However, T. pratense, the species with the highest plasticity in depth of water uptake, was least affected by drought, suggesting an indirect effect of rooting depth on drought resistance. Our results show that niche complementarity in the depth of water uptake between shallow- and deep-rooting species may have contributed to the diversity effect in mixtures.

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17

Kurganov, Alexander. "Finite-volume schemes for shallow-water equations". Acta Numerica 27 (1 maggio 2018): 289–351. http://dx.doi.org/10.1017/s0962492918000028.

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Shallow-water equations are widely used to model water flow in rivers, lakes, reservoirs, coastal areas, and other situations in which the water depth is much smaller than the horizontal length scale of motion. The classical shallow-water equations, the Saint-Venant system, were originally proposed about 150 years ago and still are used in a variety of applications. For many practical purposes, it is extremely important to have an accurate, efficient and robust numerical solver for the Saint-Venant system and related models. As their solutions are typically non-smooth and even discontinuous, finite-volume schemes are among the most popular tools. In this paper, we review such schemes and focus on one of the simplest (yet highly accurate and robust) methods: central-upwind schemes. These schemes belong to the family of Godunov-type Riemann-problem-solver-free central schemes, but incorporate some upwinding information about the local speeds of propagation, which helps to reduce an excessive amount of numerical diffusion typically present in classical (staggered) non-oscillatory central schemes. Besides the classical one- and two-dimensional Saint-Venant systems, we will consider the shallow-water equations with friction terms, models with moving bottom topography, the two-layer shallow-water system as well as general non-conservative hyperbolic systems.

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18

Bresch, Didier, Mathieu Colin, Khawla Msheik, Pascal Noble e Xi Song. "Lubrication and shallow-water systems Bernis-Friedman and BD entropies". ESAIM: Proceedings and Surveys 69 (2020): 1–23. http://dx.doi.org/10.1051/proc/202069001.

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This paper concerns the results recently announced by the authors, in C.R. Acad. Sciences Maths volume 357, Issue 1, 1-6 (2019), which make the link between the BD entropy introduced by D. Bresch and B. Desjardins for the viscous shallow-water equations and the Bernis-Friedman (called BF in our paper) dissipative entropy introduced to study the lubrication equations. More precisely different dissipative BF entropies are obtained from the BD entropies playing with drag terms and capillarity formula for viscous shallow water type equations. This is the main idea in the paper which makes the link between two communities. The limit processes employ the standard compactness arguments taking care of the control in the drag terms. It allows in one dimension for instance to prove global existence of nonnegative weak solutions for lubrication equations starting from the global existence of nonnegative weak solutions for appropriate viscous shallow-water equations (for which we refer to appropriate references). It also allows to prove global existence of nonnegative weak solutions for fourth-order equation including the Derrida-Lebowitz-Speer-Spohn equation starting from compressible Navier-Stokes type equations.

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19

Hammer, Donald A., e Robert L. Knight. "Designing Constructed Wetlands for Nitrogen Removal". Water Science and Technology 29, n. 4 (1 febbraio 1994): 15–27. http://dx.doi.org/10.2166/wst.1994.0148.

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Many constructed wetlands adequately treat BOD5, TSS, and bacteria. However, a review of nitrogen (N) data from 52 constructed and natural wetlands in the North American data base confirmed that N removal was variable. Nitrification and denitrification require aerobic and anaerobic conditions. This paper presents case histories of systems that use alternating shallow and deep water zones to create both environments. Regression analysis of N removal and N loadings in 18 shallow-deep water systems suggested that NH4+ loading (kg N/ha/day) could be used to predict effluent NH4+ values. Combinations of shallow water-emergent vegetation and deep water-submergent vegetation with low NH4+ (and TKN) loading rates can produce very low levels of discharged NH4+.

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20

Negri, Marco, e Stefano Malavasi. "Wave Energy Harnessing in Shallow Water through Oscillating Bodies". Energies 11, n. 10 (12 ottobre 2018): 2730. http://dx.doi.org/10.3390/en11102730.

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This paper deals with wave energy conversion in shallow water, analyzing the performance of two different oscillating-body systems. The first one is a heaving float, which is a system known in the literature. The second one is obtained by coupling the heaving float with a surging paddle. In order to check the different behaviors of the multibody system and the single-body heaving float, physical models of the two systems have been tested in a wave flume, by placing them at various water depths along a sloping bottom. The systems have been tested with monochromatic waves. For each water depth, several tests have been performed varying the geometrical and mechanical parameters of the two systems, in order to find their best configurations. It has been found that the multibody system is more energetic when the float and the paddle are close to each other. Capture width ratio has been found to significantly vary with water depth for both systems: in particular, capture width ratio of the heaving float (also within the multibody system) increases as water depth increases, while capture width ratio of the paddle (within the multibody system) increases as water depth decreases. At the end, the capture width ratio of the multibody system is almost always higher than that of the heaving float, and it increases as water depth increases on average; however, the multibody advantage over single body is significant for water depth less than the characteristic dimension of the system, and decreases as water depth increases.

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21

Allen, Diana M., Peter Bayer, Grant Ferguson e Philipp Blum. "Preface: Hydrogeology of shallow thermal systems". Hydrogeology Journal 22, n. 1 (24 dicembre 2013): 1–6. http://dx.doi.org/10.1007/s10040-013-1082-0.

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22

Hoekstra, N. J., J. A. Finn, D. Hofer e A. Lüscher. "The effect of drought and interspecific interactions on depth of water uptake in deep- and shallow-rooting grassland species as determined by δ18O natural abundance". Biogeosciences 11, n. 16 (25 agosto 2014): 4493–506. http://dx.doi.org/10.5194/bg-11-4493-2014.

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Abstract. Increased incidence of drought, as predicted under climate change, has the potential to negatively affect grassland production. Compared to monocultures, vertical belowground niche complementarity between shallow- and deep-rooting species may be an important mechanism resulting in higher yields and higher resistance to drought in grassland mixtures. However, very little is known about the belowground responses in grassland systems and increased insight into these processes may yield important information both to predict the effect of future climate change and better design agricultural systems to cope with this. This study assessed the effect of a 9-week experimental summer drought on the depth of water uptake of two shallow-rooting species (Lolium perenne L. and Trifolium repens L.) and two deep-rooting species (Cichorium intybus L. and Trifolium pratense L.) in grassland monocultures and four-species mixtures by using the natural abundance δ18O isotope method. We tested the following three hypotheses: (1) drought results in a shift of water uptake to deeper soil layers, (2) deep-rooting species take up a higher proportion of water from deeper soil layers relative to shallow-rooting species, and (3) as a result of interspecific interactions in mixtures, the water uptake of shallow-rooting species becomes shallower when grown together with deep-rooting species and vice versa, resulting in reduced niche overlap. The natural abundance δ18O technique provided novel insights into the depth of water uptake of deep- and shallow- rooting grassland species and revealed large shifts in depth of water uptake in response to drought and interspecific interactions. Compared to control conditions, drought reduced the proportional water uptake from 0–10 cm soil depth (PCWU0–10) of L. perenne, T. repens and C. intybus in monocultures by on average 54%. In contrast, the PCWU0–10 of T. pratense in monoculture increased by 44%, and only when grown in mixture did the PCWU0–10 of T. pratense decrease under drought conditions. In line with hypothesis (2), in monoculture, the PCWU0–10 of shallow-rooting species L. perenne and T. repens was 0.53 averaged over the two drought treatments, compared to 0.16 for the deep-rooting C. intybus. Surprisingly, in monoculture, water uptake by T. pratense was shallower than for the shallow-rooting species (PCWU0–10 = 0.68). Interspecific interactions in mixtures resulted in a shift in the depth of water uptake by the different species. As hypothesised, the shallow-rooting species L. perenne and T. repens tended to become shallower, and the deep-rooting T. pratense made a dramatic shift to deeper soil layers (reduction in PCWU0–10 of 58% on average) in mixture compared to monoculture. However, these shifts did not result in a reduction in the proportional similarity of the proportional water uptake from different soil depth intervals (niche overlap) in mixtures compared to monocultures. There was no clear link between interspecific differences in depth of water uptake and the reduction of biomass production under drought compared to control conditions (drought resistance). Cichorium intybus, the species with water uptake from the deepest soil layers was one of the species most affected by drought. Interestingly, T. pratense, which was least affected by drought, also had the greatest plasticity in depth of water uptake. This suggests that there may be an indirect effect of rooting depth on drought resistance, as it determines the potential plasticity in the depth of water uptake.

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23

Wiklund, K. "Wave interactions in a shallow-water model". Nonlinear Processes in Geophysics 5, n. 3 (30 settembre 1998): 137–44. http://dx.doi.org/10.5194/npg-5-137-1998.

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Abstract. By using a Hamiltonian method, non-linear three-wave interaction in a class of systems related to the shallow water model is considered and a general coupling coefficient is presented. In the special case where two inertial waves and one Rossby wave interact resonantly, it is found that even a very small shear of the background velocity can be important in the interaction process. The stability of the system is considered by using a pseudo-energy method. Some implications for the dynamics of atmospheric flows are pointed out.

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Prieto, Iván, Francisco I. Pugnaire e Ronald J. Ryel. "Water uptake and redistribution during drought in a semiarid shrub species". Functional Plant Biology 41, n. 8 (2014): 812. http://dx.doi.org/10.1071/fp13300.

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In arid systems, most plant mortality occurs during long drought periods when water is not available for plant uptake. In these systems, plants often benefit from scarce rain events occurring during drought but some of the mechanisms underlying this water use remain unknown. In this context, plant water use and redistribution after a large rain event could be a mechanism that allows deep-rooted shrubs to conservatively use water during drought. We tested this hypothesis by comparing soil and plant water dynamics in Artemisia tridentata ssp. vaseyana (Rydb.) Beetle shrubs that either received a rain event (20 mm) or received no water. Soil water content (SWC) increased in shallow layers after the event and increased in deep soil layers through hydraulic redistribution (HR). Our results show that Artemisia shrubs effectively redistributed the water pulse downward recharging deep soil water pools that allowed greater plant water use throughout the subsequent drought period, which ameliorated plant water potentials. Shrubs used shallow water pools when available and then gradually shifted to deep-water pools when shallow water was being used up. Both HR recharge and the shift to shallow soil water use helped conserve deep soil water pools. Summer water uptake in Artemisia not only improved plant water relations but also increased deep soil water availability during drought.

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Macêdo, Antônia B. M., Raimundo N. T. Costa, Danielle F. de Araújo e Kenya G. Nunes. "Water productivity with localized irrigation using groundwater and reuse water in the cultivation of plant species". Revista Brasileira de Engenharia Agrícola e Ambiental 24, n. 4 (aprile 2020): 219–24. http://dx.doi.org/10.1590/1807-1929/agriambi.v24n4p219-224.

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ABSTRACT This study aimed to analyze the water saving potential of replacing the traditional, furrow-irrigated banana crop in the Curu-Pentecoste Irrigated Perimeter with localized systems by inserting new cropping plans and sources of groundwater and reuse water. An analysis of the support capacity in shallow tube wells for irrigation was also performed, considering the scenario of full recharge and water scarcity. The economic analysis was performed using the profitability indicators of the investment analysis: benefit/cost ratio, net present value, internal rate of return and payback period. Water productivity data reveal that cropping plans associated with alternative sources of water from shallow tube wells and reuse of the excess surface irrigation water in localized systems are economically more attractive than traditional, furrow-irrigated banana crop. The support capacity of shallow tube wells reveals that the exploitation of this underground water resource in the region is a viable alternative for irrigation of small areas. With the exception of banana, the other scenarios analyzed showed positive cash flows from the second year.

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Yano, Jun-Ichi, James C. McWilliams, Mitchell W. Moncrieff e Kerry A. Emanuel. "Hierarchical Tropical Cloud Systems in an Analog Shallow-Water Model". Journal of the Atmospheric Sciences 52, n. 10 (maggio 1995): 1723–42. http://dx.doi.org/10.1175/1520-0469(1995)052<1723:htcsia>2.0.co;2.

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Lobeiras, Jacobo, Moisés Viñas, Margarita Amor, Basilio B. Fraguela, Manuel Arenaz, JA García e MJ Castro. "Parallelization of shallow water simulations on current multi-threaded systems". International Journal of High Performance Computing Applications 27, n. 4 (5 dicembre 2012): 493–512. http://dx.doi.org/10.1177/1094342012464800.

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Fu, Xiaoyu, e V. D. Sharma. "Cauchy problem for quasilinear hyperbolic systems of shallow water equations". Applicable Analysis 92, n. 11 (novembre 2013): 2309–19. http://dx.doi.org/10.1080/00036811.2012.734376.

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Schneider, Kleiton A., José M. Gallardo, Dinshaw S. Balsara, Boniface Nkonga e Carlos Parés. "Multidimensional approximate Riemann solvers for hyperbolic nonconservative systems. Applications to shallow water systems". Journal of Computational Physics 444 (novembre 2021): 110547. http://dx.doi.org/10.1016/j.jcp.2021.110547.

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Cardoso-Ribeiro, Flávio Luiz, Denis Matignon e Laurent Lefèvre. "Dissipative Shallow Water Equations: a port-Hamiltonian formulation". IFAC-PapersOnLine 54, n. 19 (2021): 167–72. http://dx.doi.org/10.1016/j.ifacol.2021.11.073.

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Yang, Zhuan Yun. "Feasibility Analysis and Status of Shallow Pipe-Jacking Technology in Urban Drainage Systems". Key Engineering Materials 480-481 (giugno 2011): 1278–82. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.1278.

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Considering the current domestic situation that there is no provision for shallow pipe-jacking (with overburden soil layer not thicker than 3 m and 1.5 times of the pipe external diameter) in the existing water supply and drainage pipeline engineering design and construction specifications, a comprehensive analysis and discussion, based on the actual domestic condition, is made on the feasibility of shallow pipe-jacking technology in urban drainage systems. The problems confronting the shallow pipe-jacking technology theory research are also analyzed and the research status of shallow curve pipe-jacking technology is introduced.

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Harlamova, Anna Eduardovna, Mikhail Nikolaevich Pokusaev e Alexei Viktorovich Trifonov. "Analysis of ship accidents caused by unreliable operation of cooling systems of ship power plants". Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2023, n. 2 (18 maggio 2023): 30–40. http://dx.doi.org/10.24143/2073-1574-2023-2-30-40.

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The article considers transport accidents on watercrafts in inland waterways, sea and ocean waters caused by unreliable operation of the main systems during operation in ice and shallow water conditions difficult for naviga-tion and by the violations technical operation rules by the crew members. There are given the statistical data on the accidents and causes of accidents on the water. Frequent breakdowns due to unreliable operation of the open (two-circuit) cooling system of the ship’s power plants are stated. Open systems, in which fresh water circulating through cooled power equipment is cooled by the seawater, do not provide the required reliable operation in shallow water and broken ice, causing the shutdown of the ship power plant or an emergency situation. Mechanical impurities entering the cooling system cause corrosion-erosive destruction of the pipelines, main elements and operational load on seawater filters. In the winter, the operation of the ship in shallow sections of the routes leads to clogging of sea chests with small ice particles (studge ice) and a poor seawater intake for cooling ship power units. The ship systems fail using seawater, which makes difficult the operation of the cooling system of the power plant. It has been inferred that using closed cooling systems makes it possible to solve the problem of reliable functioning of the watercrafts in the conditions of shallow waters and broken ice.

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Park, Eungyu, e Hongbin Zhan. "Hydraulics of horizontal wells in fractured shallow aquifer systems". Journal of Hydrology 281, n. 1-2 (settembre 2003): 147–58. http://dx.doi.org/10.1016/s0022-1694(03)00206-3.

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Al-Khaled, Kamel, e M. K. Al-Safeen. "Homotopy Perturbation Method For Fractional Shallow Water Equations". Sultan Qaboos University Journal for Science [SQUJS] 19, n. 1 (1 giugno 2014): 74. http://dx.doi.org/10.24200/squjs.vol19iss1pp74-86.

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In this paper, the homotopy perturbation method is adopted to find explicit and numerical solutions for systems of non-linear fractional shallow water equations. The fractional derivatives are described in the Caputo sense. We apply both the homotopy perturbation method and the homotopy analysis method, to solve certain shallow water equations with time-fractional derivatives, and explicitly construct convergent power series solutions. The results obtained reveal that these methods are both very effective and simple for finding approximate solutions. Some numerical examples and plots are presented to illustrate the efficiency and reliability of these methods.

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35

Ferencz, Beata, e Jarosław Dawidek. "Water exchange of three shallow Łęczna-Włodawa Lakes". Limnological Review 12, n. 2 (1 dicembre 2012): 65–72. http://dx.doi.org/10.2478/v10194-011-0045-x.

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AbstractThe research was carried out in three Łęczna-Włodawa lake-catchment systems, during the hydrological years 2007-2009. The observed lakes varied in terms of basin morphometry and catchment features. The hydrological functioning of the lakes resulted from three main factors: 1) storage capacity of the lake basin, 2) catchment area and relief, 3) human impact on water distribution. The vertical water exchange ratio in Lake Sumin was almost four-times higher than flushing time. In Lakes Rotcze and Syczyńskie horizontal water exchange, presented as flushing time was significantly higher than the vertical one.

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36

Turbal, Yuriy, Mariana Turbal e Andrii Bomba. "Modeling of the solitary waves trajectories in “shallow water” environme". Modeling Control and Information Technologies, n. 6 (22 novembre 2023): 96–101. http://dx.doi.org/10.31713/mcit.2023.027.

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Solitary waves in the “shallow water” environment are considered and approximate approach to calculation and prediction of trajectories of these waves is proposed. We use an approach which was developed in recent years and was called the T-representations method. This method allows to move away from the exact solutions of the corresponding systems of differential equations and construct the trajectory approximately, in fact estimating only the point of maximum of the wave amplitude and its displacement. An appropriate mathematical simplification makes efficient computer simulations possible. In recent years, software packages have been actively used to monitor and predict a number of dangerous natural phenomena, such as Earth Alerts, Pacific Tsunami Warning System, Wave Monitoring Sites and others. But these systems do not take solitary waves into account. Using our approach, it is possible to refine the parameters of solitary waves in a specific environment, investigate whether such waves exist there at all and create functions taking into account solitary waves in monitoring systems.

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37

Ilin, Konstantin. "Shallow-water models for a vibrating fluid". Journal of Fluid Mechanics 833 (2 novembre 2017): 1–28. http://dx.doi.org/10.1017/jfm.2017.687.

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We consider a layer of an inviscid fluid with a free surface which is subject to vertical high-frequency vibrations. We derive three asymptotic systems of equations that describe slowly evolving (in comparison with the vibration frequency) free-surface waves. The first set of equations is obtained without assuming that the waves are long. These equations are as difficult to solve as the exact equations for irrotational water waves in a non-vibrating fluid. The other two models describe long waves. These models are obtained under two different assumptions about the amplitude of the vibration. Surprisingly, the governing equations have exactly the same form in both cases (up to the interpretation of some constants). These equations reduce to the standard dispersionless shallow-water equations if the vibration is absent, and the vibration manifests itself via an additional term which makes the equations dispersive and, for small-amplitude waves, is similar to the term that would appear if surface tension were taken into account. We show that our dispersive shallow-water equations have both solitary and periodic travelling wave solutions and discuss an analogy between these solutions and travelling capillary–gravity waves in a non-vibrating fluid.

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38

Ion, Stelian, Dorin Marinescu e Stefan-Gicu Cruceanu. "Riemann Problem for Shallow Water Equation with Vegetation". Analele Universitatii "Ovidius" Constanta - Seria Matematica 26, n. 2 (1 luglio 2018): 145–73. http://dx.doi.org/10.2478/auom-2018-0023.

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Abstract We investigate the existence of the solution of the Riemann Problem for a simplified water ow model on a vegetated surface - system of shallow water type equations. It is known that the system with discontinuous topography is non-conservative even if the porosity is absent. A system with continuous topography and discontinuous porosity is also non-conservative. In order to define Riemann solution for such systems, it is necessary to introduce a family of paths that connects the states defining the Riemann Problem. We focus our attention towards choosing such a family based on physical arguments. We provide the structure of the solution for such Riemann Problems.

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39

Umar, Emi Prasetyawati, Alfian Nawir, Hariani M. Pakka, Jamaluddin Jamaluddin, Nurfadhilah Sam Tappa e Watcharin Joemsittiprasert. "Analysis of Shallow Groundwater Quality as Consumable Water in Maros Baru District Aquifer Systems, South Sulawesi, Indonesia". International Journal of Hydrological and Environmental for Sustainability 1, n. 1 (12 febbraio 2022): 33–40. http://dx.doi.org/10.58524/ijhes.v1i1.55.

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Water is a source of necessity for humans. Water quality is very important to be considered as the source of clean water. Some people in Maros Baru District use ground wells as the source of water needs. Therefore it is important to know the physical quality and pH level of shallow wells and to know the worthiness of shallow wells in Maros Baru District with reference to Permenkes No.492/ 2010. This study examined the feasibility of water based on the physical quality and the pH level of water taken from shallow wells. The research was carried out directly in field with 14 sampling points scattered in the north, east, south, west and at the center of field. The method in observing pH value is by litmus paper and observation on the physical condition of water, well depth, well diameter and surface level of water. The result shows there were 2 locations with saltwater taste, as the location is near from the sea and rivers, while turbidity of the water influenced by condition of surround environment that was not properly maintained. From data processing, it can be concluded that as many as 5 of the 14 sampling points did not meet the eligibility standards of Permenkes No.492/2010 to be used as a source of clean water intended for drinking water.

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40

Tarasov, Sergei, Zhu Jianjun, Petr Pivnev e Mikhail Gubko. "Low-frequency parametric systems in the shallow sea". E3S Web of Conferences 196 (2020): 02017. http://dx.doi.org/10.1051/e3sconf/202019602017.

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The theoretical model of acoustic wave propagation in the ice-water layer is developed, with, taking into account the velocity dispersion. New opportunities for monitoring the marine environment on long routes, including those covered with ice, are discussed when using parametric sonar antennas. The results of research demonstrating single-mode excitation of a waveguide by a parametric array in a wide frequency band are presented. The possibility of compression of a broadband signal during its propagation, as a result of waveguide dispersion, which leads to an increasing of signal intensity, is shown. The results of experimental studies of the propagation characteristics of a wide-band acoustic signal of a parametric hydroacoustic array in a shallow sea are presented.

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41

Bresch, Didier, Benoît Desjardins e Chi-Kun Lin. "On Some Compressible Fluid Models: Korteweg, Lubrication, and Shallow Water Systems". Communications in Partial Differential Equations 28, n. 3-4 (6 gennaio 2003): 843–68. http://dx.doi.org/10.1081/pde-120020499.

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42

Bellafiore, D., L. Zaggia, R. Broglia, C. Ferrarin, F. Barbariol, S. Zaghi, G. Lorenzetti, G. Manfè, F. De Pascalis e A. Benetazzo. "Modeling ship-induced waves in shallow water systems: The Venice experiment". Ocean Engineering 155 (maggio 2018): 227–39. http://dx.doi.org/10.1016/j.oceaneng.2018.02.039.

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43

Bouarfa, S., e D. Zimmer. "Water-table shapes and drain flow rates in shallow drainage systems". Journal of Hydrology 235, n. 3-4 (agosto 2000): 264–75. http://dx.doi.org/10.1016/s0022-1694(00)00280-8.

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44

Eskilsson, C., e S. J. Sherwin. "Discontinuous Galerkin Spectral/hp Element Modelling of Dispersive Shallow Water Systems". Journal of Scientific Computing 22-23, n. 1-3 (giugno 2005): 269–88. http://dx.doi.org/10.1007/s10915-004-4140-x.

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45

Yan, Kai, e Zhaoyang Yin. "Initial boundary value problems for the two-component shallow water systems". Revista Matemática Iberoamericana 29, n. 3 (2013): 911–38. http://dx.doi.org/10.4171/rmi/744.

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46

Castro Díaz, M. J., J. A. López-García e Carlos Parés. "High order exactly well-balanced numerical methods for shallow water systems". Journal of Computational Physics 246 (agosto 2013): 242–64. http://dx.doi.org/10.1016/j.jcp.2013.03.033.

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47

Ostapenko, V. V. "Complete systems of conservation laws for two-layer shallow water models". Journal of Applied Mechanics and Technical Physics 40, n. 5 (settembre 1999): 796–804. http://dx.doi.org/10.1007/bf02468461.

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48

CASTRO, MANUEL J., ALBERTO PARDO MILANÉS e CARLOS PARÉS. "WELL-BALANCED NUMERICAL SCHEMES BASED ON A GENERALIZED HYDROSTATIC RECONSTRUCTION TECHNIQUE". Mathematical Models and Methods in Applied Sciences 17, n. 12 (dicembre 2007): 2055–113. http://dx.doi.org/10.1142/s021820250700256x.

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Abstract (sommario):

The goal of this paper is to generalize the hydrostatic reconstruction technique introduced in Ref. 2 for the shallow water system to more general hyperbolic systems with source term. The key idea is to interpret the numerical scheme obtained with this technique as a path-conservative method, as defined in Ref. 35. This generalization allows us, on the one hand, to construct well-balanced numerical schemes for new problems, as the two-layer shallow water system. On the other hand, we construct numerical schemes for the shallow water system with better well-balanced properties. In particular we obtain a Roe method which solves exactly every stationary solution, and not only those corresponding to water at rest.

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49

Niroumand-Jadidi, Milad, Nima Pahlevan e Alfonso Vitti. "Mapping Substrate Types and Compositions in Shallow Streams". Remote Sensing 11, n. 3 (29 gennaio 2019): 262. http://dx.doi.org/10.3390/rs11030262.

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Remote sensing of riverbed compositions could enable advances in hydro-morphological and habitat modeling. Substrate mapping in fluvial systems has not received as much attention as in nearshore, optically shallow inland, and coastal waters. As finer spatial-resolution image data become more available, a need emerges to expand research on the remote sensing of riverbed composition. For instance, research to date has primarily been based on spectral reflectance data from above the water surface without accounting for attenuation by the water-column. This study analyzes the impacts of water-column correction for substrate mapping in shallow fluvial systems (depth < 1 m). To do so, we performed three different experiments: (a) analyzing spectroscopic measurements in a hydraulic laboratory setting, (b) simulating water-leaving radiances under various optical scenarios, and (c) evaluating the potential to map bottom composition from a WorldView-3 (WV3) image of a river in Northern Italy. Following the retrieval of depth and diffuse attenuation coefficient ( K d ), bottom reflectances were estimated using a water-column correction method. The results indicated significant enhancements in streambed maps based on bottom reflectances relative to maps produced from above-water spectra. Accounting for deep-water reflectance, embedded in the water-column correction, was demonstrated to have the greatest impact on the retrieval of bottom reflectance in NIR bands, when the water column is relatively thick (>0.5 m) and/or when the water is turbid. We also found that the WV3’s red-edge band (i.e., 724 nm) considerably improved the characterization of submerged aquatic vegetation (SAV) densities from either above-water or retrieved bottom spectra. This study further demonstrated the feasibility of mapping SAV density classes from a WV3 image of the Sarca River in Italy by retrieving the bottom reflectances.

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50

Pearson, H. W., S. T. Silva Athayde, G. B. Athayde e S. A. Silva. "Implications for physical design: the effect of depth on the performance of waste stabilization ponds". Water Science and Technology 51, n. 12 (1 giugno 2005): 69–74. http://dx.doi.org/10.2166/wst.2005.0429.

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Studies on experimental primary facultative ponds showed that varying the depth from 1.25 m to 2.3 m had no effect on the rates of BOD removal. In contrast k values for FC removal rates were higher in the shallower (1.25 m) facultative ponds. The risk of odour release via H2S production was higher in the 2.2 m ponds than the 1.25 m ponds and NH3 removal was much better in the 1.25 m facultative ponds. A comparison of the efficiency of shallow 5-pond series (1.0 m and 0.61 m deep) with a 2.2 m deep series showed that the shallow systems were more efficient at FC removal, but the deeper series actually saved land area for the same FC final effluent quality under tropical conditions. However, efficient nutrient removal (N and P) only occurred in the shallow series and effluent standards for nutrient concentrations are unlikely to be met by 2.2 m deep 5-pond series in contrast to the norms for pathogen removal.

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