Articoli di riviste: "Runoff Measurement Mathematical models"

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Taylor, K., J. A. D. Ranga Niroshan Appuhamy, J. Dijkstra e E. Kebreab. "Development of mathematical models to predict calcium, magnesium and selenium excretion from lactating Holstein cows". Animal Production Science 58, n. 3 (2018): 489. http://dx.doi.org/10.1071/an16307.

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The aim of this study was to develop and evaluate mathematical models that predict mineral excretion, particularly calcium (Ca), magnesium (Mg) and selenium (Se), from lactating dairy cows. Mineral excretion can be affected by several dietary factors. A deficiency in Ca or Mg application to pasture, among other factors, can contribute to grass tetany or wheat pasture poisoning in cows, whereas an excess can cause runoff into water supplies. Manure application with high Se concentration can also result in runoff, causing the bioaccumulation of selenium in aquatic ecosystems, wetland habitats and estuaries, leading to toxic levels in fish. A database composed of studies relating to mineral utilisation in lactating dairy cows conducted after and including the year 2000 was compiled. A meta-analysis was conducted with the aim of creating multiple empirical equations to predict Ca, Mg and Se excretion from lactating dairy cows. Calcium intake, feed Ca content, milk yield, milk protein content and acid detergent fibre content in diet were positively and linearly related to Ca excretion. Dietary crude protein content and milk fat content were negatively related to Ca excretion. Magnesium intake, feed Mg content and milk yield were positively and linearly related to Mg excretion. Selenium content of diet and dry matter intake were linearly and positively related to Se excretion. Two sets of models were developed using or excluding the intake variable and both sets of models were evaluated with independent data originating from commercial herd or individual animals. In general, intake measurements improved prediction when evaluated with independent datasets (root mean square prediction error = 8% to 19% vs 14% to 26% of the average observed value). There were substantial mean biases, particularly those evaluated with data from a commercial farm, perhaps due to inaccurate feed intake measurements. Although there was generally good agreement between predicted and observed mineral excretion, model development and evaluation would benefit from an expanded database.

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Chen, Jiongfeng, e Wan-chang Zhang. "A new numerical model for simulating top surface soil moisture and runoff". Engineering Computations 35, n. 3 (8 maggio 2018): 1344–63. http://dx.doi.org/10.1108/ec-01-2017-0031.

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PurposeThis paper aims to construct a simplified distributed hydrological model based on the surveyed watershed soil properties database.Design/methodology/approachThe new established model requires fewer parameters to be adjusted than needed by former hydrological models. However, the achieved stream-flow simulation results are similar and comparable to the classic hydrological models, such as the Xinanjiang model and the TOPMODEL.FindingsGood results show that the discharge and the top surface soil moisture can be simultaneously simulated, and that is the exclusive character of this new model. The stream-flow simulation results from two moderate hydrological watershed models show that the daily stream-flow simulation achieved the classic hydrological results shown in the TOPMODEL and Xinanjiang model. The soil moisture validation results show that the modeled watershed scale surface soil moisture has general agreement with the obtained measurements, with a root-mean-square error (RMSE) value of 0.04 (m3/m3) for one of the one-measurement sites and an averaged RMSE of 0.08 (m3/m3) over all measurements.Originality/valueIn this paper, a new simplified distributed hydrological model was constructed.

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Johst, M., S. Uhlenbrook, N. Tilch, B. Zillgens, J. Didszun e R. Kirnbauer. "An attempt of process-oriented rainfall-runoff modeling using multiple-response data in an alpine catchment, Loehnersbach, Austria". Hydrology Research 39, n. 1 (1 febbraio 2008): 1–16. http://dx.doi.org/10.2166/nh.2008.035.

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The development of process-oriented hydrological models, which are able to simulate hydrological processes distributed in space and time, is crucial for optimal management of water resources. The model TACD (tracer aided catchment model, distributed) was modified and applied to the mountainous Loehnersbach catchment (16 km2), Kitzbueheler Alps, Austria, with the aim of simulating the dominant hydrological processes in a distributed way. It can be seen as a further developed, fully distributed version of the HBV-model with a more process-based runoff generation routine, which uses a spatial delineation of hydrological response units (HRUs). Good overall runoff simulations could be obtained for the whole catchment. Additional data, i.e. discharge from sub-catchments, snow height measurements and dissolved silica concentrations, enabled to some extent the evalulation of the simulation of single processes. Certain periods, e.g. short-term runoff fluctuations during snow melt periods, could not be simulated well even when different model modifications were executed. This indicates model shortcomings because of incomplete process understanding and the necessity for further experimental research as well as for new concepts of model structure. In particular, the understanding and mathematical description of subsurface storm flows has to be improved. The impact of different HRU delineations on discharge simulations at the catchment outlet was relatively low, as long as the direct runoff producing units remained constant. However, the impact on runoff predictions at sub-catchment scale was significant. This indicates an ’averaging out’ effect for peculiarities and errors of runoff predictions at larger scales.

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Rosso, R., M. C. Rulli e D. Bocchiola. "Transient catchment hydrology after wildfires in a Mediterranean basin: runoff, sediment and woody debris". Hydrology and Earth System Sciences 11, n. 1 (17 gennaio 2007): 125–40. http://dx.doi.org/10.5194/hess-11-125-2007.

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Abstract. The transient effect of forest fires on runoff, erosion and yield of woody biomass has been investigated by combining the experimental approach with mathematical models of hydrological processes. The case study is the Branega creek in Liguria, Italy, where a forest fire in August 2003 caused substantial changes to soil and vegetation, and left a considerable amount of woody debris on the ground. Immediately after the fire, rainfall simulator experiments in adjacent burned and unburned plots showed the extent to which fire had increased runoff and erosion rates. A distributed hydrological model using the tube-flux approach, calibrated on experimental measurements, has been used to investigate hill slope and channel erosion in a small sub-catchment, 1.5 ha in area, nested in the Branega basin. Simulation runs show that the model accommodates the observed variability of runoff and erosion under disturbed and undisturbed conditions. A model component describing the delivery of wood from hill slopes to the channel in post-fire conditions, validated against local survey data, showed that the removal and transport of woody biomass can be reproduced using an integrated hydrological approach. Hence, transient complexity after wildfires can be addressed by such an approach with empirically determined physically-based parameters.

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Svetlitchnyi, А. A., e A. V. Piatkova. "Spatially distributed GIS-realized mathematical model of rainstorm erosion losses of soil". Journal of Geology, Geography and Geoecology 28, n. 3 (10 ottobre 2019): 562–71. http://dx.doi.org/10.15421/111953.

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In connection with the wide and ever increasing spread of erosion degradation of agricultural lands in Ukraine, the task of developing mathematical models and methods for calculating water erosion of soils corresponding to the current level of erosion study and the demands of soil protection practices is becoming increasingly important. The article is devoted to the development of a spatially distributed GIS-implemented mathematical model of rainstorm soil erosion, which accounts for most of the annual soil losses (in the Steppe zone, for example, about 90 %). The development of the model is based on the most theoretically and informationally grounded model for the Steppe and Forest-Steppe of Ukraine , “the logical-mathematical model of rainstorm soil outwash” developed by H. I. Shvebs (1974, 1981), as well as the results of theoretical and field studies and mathematical modeling of the slope runoff and water erosion of soil, carried out at the Department of Physical Geography and Environmental Management of Odessa I. I. Mechnikov National University in the 1990s - 2010s, and also the possibilities of modern geoinformation technologies. For the spatial implementation of the model, a raster model of spatial data and operators of the PCRaster GIS-package (University of Utrecht, the Netherlands) were used, integrated with the Basic programming language into a single system that provides an implementation of the computational algorithm. The developed physical-statistical model of soil erosion-sedimentation takes into account the peculiarities of the formation of slope runoff and soil outwash in conditions of excessive nonstationarity of heavy rainfall, as well as spatial heterogeneity of all major natural and economic factors of water erosion on a slope, including slope steepness, exposure, longitudinal and transverse forms of slopes, soil erodibility, structure of sown areas and anti-erosion measures. Checking the adequacy of the mathematical model was performed using observational data of four experimental catchments ; two runoff plots of the Moldavan water-balance station with total area of 0.08 ha, the Ploska catchment with area of 8.5 ha (Boguslav field experimental base of Ukrainian Hydrometeorological Institute) and the Sukha catchment with area of 63 ha (Veliko-Anadol water-balance station) with observation periods of 17-31 years. Comparison of the calculated average over the catchment area of mean annual values of rainstorm soil losses, with the corresponding values obtained from measurements on these catchments, made on the basis of Nash-Sutcliff efficiency criterion (NS), allowed us to evaluate the quality of the model as good (NS = 0.72).

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Djordjević, S., D. Prodanović, Č. Maksimović, M. Ivetić e D. Savić. "SIPSON – Simulation of Interaction between Pipe flow and Surface Overland flow in Networks". Water Science and Technology 52, n. 5 (1 settembre 2005): 275–83. http://dx.doi.org/10.2166/wst.2005.0143.

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The new simulation model, named SIPSON, based on the Preissmann finite difference method and the conjugate gradient method, is presented in the paper. This model simulates conditions when the hydraulic capacity of a sewer system is exceeded, pipe flow is pressurized, the water flows out from the piped system to the streets, and the inlets cannot capture all the runoff. In the mathematical model, buried structures and pipelines, together with surface channels, make a horizontally and vertically looped network involving a complex interaction of flows. In this paper, special internal boundary conditions related to equivalent inlets are discussed. Procedures are described for the simulation of manhole cover loss, basement flooding, the representation of street geometry, and the distribution of runoff hydrographs between surface and underground networks. All these procedures are built into the simulation model. Relevant issues are illustrated on a set of examples, focusing on specific parameters and comparison with field measurements of flooding of the Motilal ki Chal catchment (Indore, India). Satisfactory agreement of observed and simulated hydrographs and maximum surface flooding levels is obtained. It is concluded that the presented approach is an improvement compared to the standard “virtual reservoir” approach commonly applied in most of the models.

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Ellis, Kathryn K., Timothy Callahan, Dianne I. Greenfield, Denise Sanger, Joshua Robinson e Martin Jones. "Measuring and Modeling Flow Rates in Tidal Creeks: A Case Study from the Central Coast of South Carolina". Journal of South Carolina Water Resources, n. 4 (1 giugno 2017): 21–39. http://dx.doi.org/10.34068/jscwr.04.03.

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The purpose of this study was to collect site- and condition-specific hydrology data to better understand the water flow dynamics of tidal creeks and terrestrial runoff from surrounding watersheds. In this paper, we developed mathematical models of tidal creek flow (discharge) in relation to time during a tidal cycle and also estimated terrestrial runoff volume from design storms to compare to tidal creek volumes. Currently, limited data are available about how discharge in tidal creeks behaves as a function of stage or the time of tide (i.e., rising or falling tide) for estuaries in the southeastern United States, so this information fills an existing knowledge gap. Ultimately, findings from this study will be used to inform managers about numeric nutrient criteria (nitrogen-N and phosphorus-P) when it is combined with biological response (e.g., phytoplankton assemblages) data from a concurrent study. We studied four tidal creek sites, two in the Ashepoo-Combahee-Edisto (ACE) Basin and two in the Charleston Harbor system. We used ArcGIS to delineate two different watersheds for each study site, to classify the surrounding land cover using the NOAA Coastal Change Analysis Program (C-CAP) data, and to analyze the soils using the NRCS Soil Survey Geographic database (SSURGO). The size of the U.S. Geological Survey’s Elevation Derivatives for National Application (EDNA) watersheds varied from 778 to 2,582 ha; smaller geographic watersheds were delineated for all sites (except Wimbee) for stormwater modeling purposes. The two sites in Charleston Harbor were within the first-order Horlbeck Creek and the second-order Bulls Creek areas. The ACE Basin sites were within the third-order Big Bay Creek and the fourth-order Wimbee Creek areas. We measured the stage and discharge in each creek with an acoustic Doppler current profiler (ADCP) unit for multiple tide conditions over a 2-year period (2015–2016) with the goal of encompassing as large of a range of tide stage and discharge data measurements as possible. The Stormwater Runoff Modeling System (SWARM) was also used to estimate the potential water entering the creeks from the land surface; this volume was very small relative to the tide water volume except for the more-developed Bulls Creek watershed. The results show that the peak discharge occurred on the ebb tide and that the duration of the flood tide spanned a longer period of time; both of these observations are consistent with traits associated with an ebb-dominated tidal creek system. The tidal inflow and outflow (flood and ebb tides, respectively) showed an asymmetrical pattern with respect to stage and discharge; peak discharge during the flood (rising) tide occurred at a higher stage than for the peak discharge during the ebb (falling) tide. This is not an unexpected result, as the water on an ebb tide is moving down gradient funneled through the creek channel toward the coast. Furthermore, water moving with the rising flood tide must overcome frictional losses due to the marsh bank and vegetation; i.e., the peak discharge can only happen when the water has risen above these impediments. We infer from the flow dynamics data that faster water velocities during ebb tide imply that more erosive energy could transport a larger mass of suspended solids and associated nutrients (e.g., orthophosphate) from the estuary to the coastal ocean. However, the discharge and runoff modeling indicate that land-based flux was important in the developed Bulls Creek watershed, but not at the larger and less-developed Big Bay Creek watershed. At Big Bay Creek, the relatively large tidal discharge volume compared to the smaller potential runoff generated within the watershed indicates that the creek could potentially dilute terrestrial runoff contaminants. Smaller, more-urbanized tidal wetland systems may not benefit from such dilution effects and thus are vulnerable to increased runoff from adjacent developed landscapes.

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Mańko, Robert, e Norbert Laskowski. "Comparative analysis of the effectiveness of the conceptual rainfall-runoff hydrological models on the selected rivers in Odra and Vistula basins". ITM Web of Conferences 23 (2018): 00025. http://dx.doi.org/10.1051/itmconf/20182300025.

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Identification of physical processes occurred in the watershed is one of the main tasks in hydrology. Currently the most efficient hydrological processes describing and forecasting tool are mathematical models. They can be defined as a mathematical description of relations between specified attributes of analysed object. It can be presented by: graphs, arrays, equations describing functioning of the object etc. With reference to watershed a mathematical model is commonly defined as a mathematical and logical relations, which evaluate quantitative dependencies between runoff characteristics and factors, which create it. Many rainfall-runoff linear reservoirs conceptual models have been developed over the years. The comparison of effectiveness of Single Linear Reservoir model, Nash model, Diskin model and Wackermann model is presented in this article.

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Ebrahimian, H., e A. Liaghat. "Field evaluation of various mathematical models for furrow and border irrigation systems". Soil and Water Research 6, No. 2 (30 maggio 2011): 91–101. http://dx.doi.org/10.17221/34/2010-swr.

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In this study, three mathematical models in the SIRMOD package including the hydrodynamic (HD), zero inertia (ZI), and kinematic wave (KW) models were tested using the data from several field experiments for both border and furrow irrigation systems. Five data sets for borders and seven data sets for furrows were used in this assessment. The results indicated that the performance of all models was satisfactory for the prediction of the advance and recession times. There was no difference in the prediction of the advance and recession times and infiltrated and runoff volumes between the hydrodynamic and zero-inertia approaches of the SIRMOD software. The HD, ZI, and KW models predicted the recession times better than the advance times for both the experimental borders and furrows. The predicted advance and recession times were estimated by these models more accurately than the infiltrated and runoff volumes. Also the accuracy of these models for the prediction of the advance and recession times was better for the experimental furrows in comparison with the experimental borders.

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Stentsel, Y., O. Porkuian, K. Litvinov e T. Sotnikova. "Mathematical Models of Additional Measurement Errors of Control Means". Metrology and instruments, n. 2 (3 maggio 2019): 43–51. http://dx.doi.org/10.33955/2307-2180(2)2019.43-51.

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Studies have shown that under industrial conditions there is rarely a correction of the current measurement result when the influencing parameter deviates from the normalized value. The existing method of determining the additional measurement error is that in order to obtain the real value of the measurement result, the correction is calculated, which leads to the current value of indexes of control means. The correction value is determined by dividing the degree of the influencing parameter deviation by the normalized value of the additional error. This method of determining the correction is not accurate enough, since it does not take into account the nonlinear dependence of the additional measurement error on the change in the influencing parameter, as well as on the current value of the output signal of control means. To determine the real value of the measured parameter and the additional error, the method of integral-type functional is proposed. The essence of the method is in determining the difference of planes under the nominal and current parts of the static characteristic, limited by the measurement range. It is shown that the planes difference depends on the current and real values of the output signal of control means, as well as on the influencing parameter deviation. The method allows calculating the real values of the measured parameter only by the output signal of control means and the current values of the influencing parameter. The dependencies between the real value of the measured parameter, the current value of the output signal of control means and the influencing parameter deviation are established.

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Farkas, Csilla, Sigrun H. Kværnø, Alexander Engebretsen, Robert Barneveld e Johannes Deelstra. "Applying profile- and catchment-based mathematical models for evaluating the run-off from a Nordic catchment". Journal of Hydrology and Hydromechanics 64, n. 3 (1 settembre 2016): 218–25. http://dx.doi.org/10.1515/johh-2016-0022.

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AbstractKnowledge of hydrological processes and water balance elements are important for climate adaptive water management as well as for introducing mitigation measures aiming to improve surface water quality. Mathematical models have the potential to estimate changes in hydrological processes under changing climatic or land use conditions. These models, indeed, need careful calibration and testing before being applied in decision making. The aim of this study was to compare the capability of five different hydrological models to predict the runoff and the soil water balance elements of a small catchment in Norway. The models were harmonised and calibrated against the same data set. In overall, a good agreement between the measured and simulated runoff was obtained for the different models when integrating the results over a week or longer periods. Model simulations indicate that forest appears to be very important for the water balance in the catchment, and that there is a lack of information on land use specific water balance elements. We concluded that joint application of hydrological models serves as a good background for ensemble modelling of water transport processes within a catchment and can highlight the uncertainty of models forecast.

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SHENTZIS, I. D. "Mathematical models for long-term prediction of mountainous river runoff: methods, information and results". Hydrological Sciences Journal 35, n. 5 (ottobre 1990): 487–500. http://dx.doi.org/10.1080/02626669009492453.

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Khan, S. H., e L. Finkelstein. "Mathematical Modelling in Measurement and Instrumentation". Measurement and Control 44, n. 9 (novembre 2011): 277–82. http://dx.doi.org/10.1177/002029401104400904.

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This paper presents a brief outline of the use of mathematical modelling techniques in measurement and instrumentation systems and sub-systems. Following an overview of various models, it illustrates some of the recent advances in mathematical modelling of sensors and instrument transducers. This is illustrated in two case studies describing the use of numerical finite element (FE) modelling techniques for CAD and performance modelling of capacitive sensors and torque motor actuators.

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Kanso, A., B. Tassin e G. Chebbo. "A benchmark methodology for managing uncertainties in urban runoff quality models". Water Science and Technology 51, n. 2 (1 gennaio 2005): 163–70. http://dx.doi.org/10.2166/wst.2005.0044.

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In this paper we present a benchmarking methodology, which aims at comparing urban runoff quality models, based on the Bayesian theory. After choosing the different configurations of models to be tested, this methodology uses the Metropolis algorithm, a general MCMC sampling method, to estimate the posterior distributions of the models' parameters. The analysis of these posterior distributions allows a quantitative assessment of the parameters' uncertainties and their interaction structure, and provides information about the sensitivity of the probability distribution of the model output to parameters. The effectiveness and efficiency of this methodology are illustrated in the context of 4 configurations of pollutants' accumulation/erosion models, tested on 4 street subcatchments. Calibration results demonstrate that the Metropolis algorithm produces reliable inferences of parameters thus, helping on the improvement of the mathematical concept of model equations.

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Nitzan, Meir, Ofer P. Tadmor, Yuri Skomorowski, Ron Rabinowitz e Yoram Díamant. "Mathematical Models for Fetal Growth: Application for Biparietal Diameter Measurement". Fetal Diagnosis and Therapy 9, n. 5 (1994): 321–26. http://dx.doi.org/10.1159/000263955.

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Stentsel, Yo I., e K. A. Litvinov. "Mathematical Models of Conservative Objects of Control". Metrology and instruments, n. 1 (2 marzo 2020): 30–36. http://dx.doi.org/10.33955/2307-2180(1)2020.30-36.

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Trend analysis and record charts different technological parameter in the heat power, chemical and oil refining industry showed, that most of them are oscillatory in nature. In order to reduce the amplitude of the oscillations, filters are used, and for the actual value of the measured quantity — their average value. Research has found, that the oscillatory-pulse nature of trends and diagrams of measured values is observed in multi-parameter technological objects of control, which have valve valve strapping on both input and output material, heat or energy flows. It is shown that valve-type regulating organs, which are used in automatic control systems, together with the technological apparatus create partial objects, which work on a conservative type. This creates new dynamic objects with three or more private conservative systems, which together create a complex multi-parameter technological control object with the oscillatory-pulse nature of the measured parameters. It was found that in many cases for such complex objects of control the average value of the measured parameter, defined with the trend, can differ significantly from its actual value. This leads to the appearance of significant measurement errors, and consequently, to an incorrect assessment of the quality of manufactured products. The task is to study the causes of the appearance of such vibrational-pulse systems, their properties, deviations of average readings along the trend from the actual value of the measured parameter, and also develop methods for reducing measurement errors. The paper presents mathematical and physical models of such conservative control systems, obtained on the basis of the theory of rheological transformations, as well as the results of their research. It is shown that the vibrational-pulse trends of the measurement parameters are a set of angular frequencies of private objects, the sum of which creates an oscillatory-pulse form of the signals of the measuring parameters.

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Bennett, J. C. "Assessment of the Impact of Land Use on Recreational Waters Using Mathematical Models". Water Science and Technology 21, n. 2 (1 febbraio 1989): 223–28. http://dx.doi.org/10.2166/wst.1989.0054.

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Mathematical models were used to assist in quantifying the impact of changing land use on the recreational waters of Pumicestone Passage. Runoff, washoff, hydrodynamic and water quality models were firstly calibrated and then used to predict levels of dissolved oxygen, total nitrogen, total phosphorus and E.coli in the Passage for two future land development scenarios. The models provided valuable tools for understanding the system response to non-point source pollutant loadings and assessing alternative scenarios. They indicated that planned development to the year 2000 would not result in significant water quality deterioration while extreme development is likely to do so to the extent of prejudicing some water uses.

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James, William, e Boregowda Shivalingaiah. "Storm water pollution modelling: buildup of dust and dirt on surfaces subject to runoff". Canadian Journal of Civil Engineering 12, n. 4 (1 dicembre 1985): 906–15. http://dx.doi.org/10.1139/l85-103.

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Many runoff models are currently in use to predict both the quantity and quality of storm water runoff. In most models, the quality algorithms need further development to gain the confidence of model users. The writers have attempted to disaggregate the accumulation process and to develop improved algorithms for pollutant buildup. The factors and processes that affect buildup include atmospheric dustfall due to plumes of dust-laden air, wind effects, vehicles, intentional removals (e.g., street cleaning), special activities (such as construction and demolition), biological decomposition, and population-related activities (e.g., vegetation density, insecticides, herbicides, fertilizers, and lawn cutting). Mathematical expressions for each of these mechanisms are presented and utilized to develop algorithms in the RUNOFF module of the SWMM3 package.A separate multiregression model is used to generate atmospheric dustfall from meteorological information; this is input to the new program (NEWBLD) to calculate pollutant accumulation on individual subcatchments. NEWBLD is interfaced with the RUNOFF block of SWMM3. A sensitivity analysis is carried out using data for the Chedoke Creek catchment in Hamilton, Ontario. The modified version of the SWMM3 RUNOFF block developed herein by incorporating the new water quality algorithms is called CHGQUAL. It is applied to an urban catchment in Hamilton, Ontario. Key words: storm water models, dust and dirt buildup, storm water pollution, urban hydrology, air pollution.

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Velmisov, Petr A., e Yuliya A. Tamarova. "Mathematical modeling of pressure measurement systems in gas-liquid media". Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva 22, n. 3 (30 settembre 2020): 352–67. http://dx.doi.org/10.15507/2079-6900.22.202003.352-367.

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The article discusses the initial-boundary value problems for systems of differential equations, which are mathematical models of the mechanical system "pipeline - pressure sensor that is designed to measure pressure in gas-liquid media. On the basis of the proposed models, the joint dynamics of the pressure sensor sensitive element and of the working medium in the pipeline connecting the sensor to the combustion chamber of the engine is investigated. To describe the movement of the working medium, linear models of the mechanics of liquid and gas are used; to describe the dynamics of the sensitive element, both linear and nonlinear models of the mechanics of a solid deformable body are used. The solutions of stated initial-boundary value problems are carried out on the basis of the Galerkin method and the finite-difference method.

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Plis, Marcin, e Henryk Rusinowski. "Identification of mathematical models of thermal processes with reconciled measurement results". Energy 177 (giugno 2019): 192–202. http://dx.doi.org/10.1016/j.energy.2019.04.076.

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Liang, Jing, Wenzhe Li, Scott Bradford e Jiří Šimůnek. "Physics-Informed Data-Driven Models to Predict Surface Runoff Water Quantity and Quality in Agricultural Fields". Water 11, n. 2 (24 gennaio 2019): 200. http://dx.doi.org/10.3390/w11020200.

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Contaminants can be rapidly transported at the soil surface by runoff to surface water bodies. Physically-based models (PBMs), which are based on the mathematical description of main hydrological processes, are key tools for predicting surface water impairment. Along with PBMs, data-driven models are becoming increasingly popular for describing the behavior of hydrological and water resources systems since these models can be used to complement or even replace physically based-models. Here we propose a new data-driven model as an alternative to a physically-based overland flow and transport model. First, we have developed a physically-based numerical model to simulate overland flow and contaminant transport. A large number of numerical simulations was then carried out to develop a database containing information about the impact of various relevant factors on surface runoff quantity and quality, such as different weather patterns, surface topography, vegetation, soil conditions, contaminants, and best management practices. Finally, the resulting database was used to train data-driven models. Several Machine Learning techniques were explored to find input-output functional relations. The results indicate that the Neural Network model with two hidden layers performed the best among selected data-driven models, accurately predicting runoff water quantity and quality over a wide range of parameters.

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Li, Tilai, Xiangyu Gao, Xinzhou Zhang e Yinshuang Wang. "IMPACT OF RUNOFF ON SALT INTRUSION OF YANGTZE ESTUARY". Coastal Engineering Proceedings 1, n. 32 (2 febbraio 2011): 49. http://dx.doi.org/10.9753/icce.v32.management.49.

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Based on one-dimensional and two-dimensional mathematical coupling models of tidal current and salinity from Datong to Yangtze estuary, the impacting scope of salt intrusion are calculated when the runoff of Datong from 4,500m3/s to 30,000m3/s, and the maximum and average value of salinity at each representative point of the estuary are given. When flow of Datong is less than 10,000 m3/s, if projects of water transfer, pumping and diversion are not taken into account at the lower reaches of Datong, the maximum salinity at the downstream reaches of Xuliujing and the average salinity at the downstream reaches of Baimaosha will exceed drinking water criteria.

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Despotović, J., J. Petrović e N. Jacimović. "Measurement, calibration of rainfall-runoff models and assessment of the return period of flooding events at urban catchment Kumodraz in Belgrade". Water Science and Technology 45, n. 2 (1 gennaio 2002): 127–33. http://dx.doi.org/10.2166/wst.2002.0037.

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For the purpose of re-design and improvement of the combined sewer system at the Kumodraz catchment in Belgrade, measurements of rainfall and runoff at the catchment were established in late 1997. Observed data are used for calibration and validation of two rainfall-runoff models: the detailed model BEMUS (Belgrade Model) and a conceptual hydrologic model Visual OTTHYMO. The major facilities of the recommended solution for re-design of the existing system are three retention ponds and outlet into a trunk. The paper briefly presents assessment of design flows for these four locations of the catchment based on results from the calibrated models. Data on intense storms that caused severe flooding within the catchment (and also all over Belgrade and other parts of Serbia) in June and July 1999 are used for comparison of design flows with a real event. During these storms the flow gauging equipment at the catchment was destroyed and only the rainfall data was available. In order to analyze the system under extreme conditions it is therefore necessary to perform hydrograph simulations. The basic idea was to check return periods of rainfall and runoff for these storms.

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Dinu, Cristian, Radu Drobot, Claudiu Pricop e Tudor Viorel Blidaru. "Genetic Programming Technique Applied for Flash-Flood Modelling Using Radar Rainfall Estimates". Mathematical Modelling in Civil Engineering 13, n. 4 (20 dicembre 2017): 27–38. http://dx.doi.org/10.1515/mmce-2017-0012.

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AbstractThe rainfall-runoff transformation is a highly complex dynamic process and the development of fast and robust modelling instruments has always been one of the most important topics for hydrology. Over time, a significant number of hydrological models have been developed with a clear trend towards a process-based approach. The downside of these types of models is the significant amount of data required for building the model and for the calibration process: in practice, the collection of all necessary data for such models proves to be a difficult task. In order to cope with this issue, various data-driven modelling techniques have been introduced for hydrological modelling as an alternative to more traditional approaches, on the basis of their capacity of mapping out complex relationships from observation data. Having the capacity to generate meaningful mathematical structures as results, genetic programming (GP) presents a high potential for rainfall-runoff modelling as a data-driven method. Using ground and radar rainfall observation, the aim of this study is to investigate the GP technique capability for modelling the rainfall-runoff process, taking into consideration a flash-flood event.

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Piotrowski, Adam P., Marzena Osuch e Jarosław J. Napiorkowski. "Joint Optimization of Conceptual Rainfall-Runoff Model Parameters and Weights Attributed to Meteorological Stations". Water Resources Management 33, n. 13 (ottobre 2019): 4509–24. http://dx.doi.org/10.1007/s11269-019-02368-8.

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Abstract Conceptual lumped rainfall-runoff models are frequently used for various environmental problems. To put them into practice, both the model calibration method and data series of the area-averaged precipitation and air temperature are needed. In the case when data from more than one measurement station are available, first the catchment-averaged meteorological data series are usually obtained by some method, and then they are used for calibration of a lumped rainfall-runoff model. However, various optimization methods could easily be applied to simultaneously calibrate both the aggregation weights attributed to various meteorological stations to obtain a lumped meteorological data series and the rainfall-runoff model parameters. This increases the problem dimensionality but allows the optimization procedure to choose the data that are most important for the rainfall-runoff process in a particular catchment, without a priori assumptions. We test the idea using two conceptual models, HBV and GR4J, and three mutually different, relatively recently proposed Evolutionary Computation and Swarm Intelligence optimization algorithms, that are applied to three catchments located in Poland and northwestern USA. We consider two cases: with and without the model error correction applied to the rainfall-runoff models. It is shown that for the calibration period, joint optimization of the weights used to aggregate the meteorological data and the parameters of the rainfall-runoff model improves the results. However, the results for the validation period are inconclusive and depend on the model, error correction, optimization algorithm, and catchment.

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BANSUDE, S. N., G. L. CHUNALE, A. A. SHINDE e PRAVENDRA KUMAR. "Comparison between two different conceptual mathematical models in prediction of direct runoff hydrographs from a small watershed". INTERNATIONAL JOURNAL OF AGRICULTURAL ENGINEERING 8, n. 1 (15 aprile 2015): 60–65. http://dx.doi.org/10.15740/has/ijae/8.1/60-65.

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27

Bityukov, V. K., A. A. Khvostov, S. A. Titov, P. A. Sotnikov e M. A. Zaichikov. "Mathematical Models of Acoustic Measurement of the Degree of Crystallinity of Rubbers". International Polymer Science and Technology 34, n. 7 (luglio 2007): 35–40. http://dx.doi.org/10.1177/0307174x0703400707.

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28

Ilkiv, V. S., Z. M. Nytrebych, P. Ya Pukach, I. V. Kohut e B. B. Pakholok. "Analysis of measurement systems mathematical models by using the comparison of functions". Mathematical Modeling and Computing 6, n. 2 (5 dicembre 2019): 268–75. http://dx.doi.org/10.23939/mmc2019.02.268.

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Ohkura, Michiko, Yasuyuki Yanagida, Taro Maeda e Susumu Tachi. "Measurement of auditory alleys in a virtual environment and their mathematical models". Systems and Computers in Japan 31, n. 4 (aprile 2000): 12–21. http://dx.doi.org/10.1002/(sici)1520-684x(200004)31:4<12::aid-scj2>3.0.co;2-#.

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30

Sun, Yuzhu, Xingfu Song, Jin Wang, Yan Luo e Jianguo Yu. "Unseeded Supersolubility of Lithium Carbonate: Experimental Measurement and Simulation with Mathematical Models". Journal of Crystal Growth 311, n. 23-24 (dicembre 2009): 4714–19. http://dx.doi.org/10.1016/j.jcrysgro.2009.09.013.

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31

Patel, Ajaykumar Bhagubhai, e Geeta S. Joshi. "Modeling of Rainfall-Runoff Correlations Using Artificial Neural Network-A Case Study of Dharoi Watershed of a Sabarmati River Basin, India". Civil Engineering Journal 3, n. 2 (28 febbraio 2017): 78–87. http://dx.doi.org/10.28991/cej-2017-00000074.

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The use of an Artificial Neural Network (ANN) is becoming common due to its ability to analyse complex nonlinear events. An ANN has a flexible, convenient and easy mathematical structure to identify the nonlinear relationships between input and output data sets. This capability could efficiently be employed for the different hydrological models such as rainfall-runoff models, which are inherently nonlinear in nature. Artificial Neural Networks (ANN) can be used in cases where the available data is limited. The present work involves the development of an ANN model using Feed-Forward Back Propagation algorithm for establishing monthly and annual rainfall runoff correlations. The hydrologic variables used were monthly and annual rainfall and runoff for monthly and annual time period of monsoon season. The ANN model developed in this study is applied to Dharoi reservoir watersheds of Sabarmati river basin of India. The hydrologic data were available for twenty-nine years at Dharoi station at Dharoi dam project. The model results yielding into the least error is recommended for simulating the rainfall-runoff characteristics of the watersheds. The obtained results can help the water resource managers to operate the reservoir properly in the case of extreme events such as flooding and drought.

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Fedorko, Gabriel, David Heinz, Vieroslav Molnár e Tomáš Brenner. "Use of mathematical models and computer software for analysis of traffic noise". Open Engineering 10, n. 1 (10 marzo 2020): 129–39. http://dx.doi.org/10.1515/eng-2020-0021.

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AbstractNoise measurement and evaluation of the existing noise situation is carried out in the vicinity of selected roads to demonstrate the need for the design of anti-noise measures or to assess the effectiveness of the measures. The selection and number of measuring points, time and intervals, the road noise measurement procedure and the measuring instruments used shall be used in accordance with the provisions of the STN ISO 1996-1 and STN ISO 1996-2 standards. During the measurement, it is also necessary to determine the microclimatic conditions of measurement, such as temperature and relative humidity, wind direction and speed, barometric pressure, duration and intensity of precipitation at the measuring point. The determinant for the definition of road traffic noise is the equivalent sound level A or the equivalent sound level in the third octave bands over a given time interval. In specific cases, it is possible to determine the equivalent sound pressure level from individual vehicle transit.

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Panidi, E., L. Trofimetz, J. Sokolova e E. Kunaeva. "LARGE-SCALE INDICATIVE MAPPING OF SOIL RUNOFF". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W2 (16 novembre 2017): 175–78. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w2-175-2017.

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In our study we estimate relationships between quantitative parameters of relief, soil runoff regime, and spatial distribution of radioactive pollutants in the soil. The study is conducted on the test arable area located in basin of the upper Oka River (Orel region, Russia). Previously we collected rich amount of soil samples, which make it possible to investigate redistribution of the Chernobyl-origin cesium-137 in soil material and as a consequence the soil runoff magnitude at sampling points. <br><br> Currently we are describing and discussing the technique applied to large-scale mapping of the soil runoff. The technique is based upon the cesium-137 radioactivity measurement in the different relief structures. Key stages are the allocation of the places for soil sampling points (we used very high resolution space imagery as a supporting data); soil samples collection and analysis; calibration of the mathematical model (using the estimated background value of the cesium-137 radioactivity); and automated compilation of the map (predictive map) of the studied territory (digital elevation model is used for this purpose, and cesium-137 radioactivity can be predicted using quantitative parameters of the relief). The maps can be used as a support data for precision agriculture and for recultivation or melioration purposes.

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Li, Yu Hong, Wei Ding e Shan Ding. "Laser Beam Measurement Based on Image Enhancement Algorithm". Advanced Materials Research 225-226 (aprile 2011): 666–69. http://dx.doi.org/10.4028/www.scientific.net/amr.225-226.666.

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This paper puts forwards a novel algorithm for laser beam measurement based on the enhancement of infrared image, which has strong noise background and low contrast. First, laser beam image were divided by “three order invariant moments” with the idea of statistical probability, and objects that need to be measured were extracted; Then, four mathematical models were established on the basis of “γ-correcting” algorithm, and an improved“(a, b, γ)-correction” algorithm which is based on PSO algorithm has been proposed by solving the mathematical models respectively. The PSO algorithm will be used in the process of the enhancement of laser beam.

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HRISSANTHOU, V., e A. PSILOVIKOS. "Distributed modeling of soil erosion and sediment transport". Bulletin of the Geological Society of Greece 34, n. 2 (1 agosto 2018): 763. http://dx.doi.org/10.12681/bgsg.17354.

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A mathematical model is used for the estimation of the annual sediment yield resulting from rainfall and runoff at the outlet of Nestos River basin (Toxotes, Thrace, Greece), where the ecologically interesting Nestos delta exists. The model is applied to that part of Nestos River basin (838 km2) which lies downstream of three dams. Two dams (Thissavros and Platanovryssi) have been already constructed, while the third one (Temenos) is under construction. The model consists of three sub-models: a rainfall-runoff sub-model, a surface erosion sub-model and a sediment transport sub-model for streams. This model is also capable of computing the annual erosion amount and sediment yield in the individual sub-basins

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Seleznev, Vadim E. "Numerical Adaptation of Pipeline Network Models on Measurement Archive". ISRN Applied Mathematics 2014 (9 febbraio 2014): 1–6. http://dx.doi.org/10.1155/2014/146591.

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We propose an adaptation method for gas dynamic pipeline network models to enable credible representation of actual properties of real simulation objects. The presentation is illustrated by fitting equivalent pipeline section roughnesses used in the models to accommodate the influence of flow resistance on gas transport parameters. The method is based on the setting up and solution of a series of special parametric identification problems based on a limited set of field measurement data at local (in space) network points. This method can be used by specialists in mathematical modeling of gas transport systems to solve practical parametric identification problems.

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Lopez, V., F. Napolitano e F. Russo. "Calibration of a rainfall-runoff model using radar and raingauge data". Advances in Geosciences 2 (24 marzo 2005): 41–46. http://dx.doi.org/10.5194/adgeo-2-41-2005.

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Abstract. Since raingauges give pointwise measurements the small scale variability of rainfall fields leads to biases on the estimation for the rainfall over the whole basin. In this context meteorological radars have several advantages since a single site is able to obtain coverage over a wide area with high temporal and spatial resolution. The purpose of this study is to compare the capability of the two different measurement systems in order to give correct input to drive rainfall-runoff models. Therefore a geomorphological model was calibrated, using firstly raingauge data and secondly radar rainfall estimates, for the Treja river basin. In this way it is possible to determine different sets of parameters and the influence of measurement system in hydrological modelling. The results shown that radar rainfall data is able to improve significantly hydrographs reconstructions.

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Cohen, S. Z., R. D. Wauchope, A. W. Klein, C. V. Eadsforth e R. L. Graney. "Pesticides report 35. Offsite transport of pesticides in water: Mathematical models of pesticide leaching and runoff (Technical Report)". Pure and Applied Chemistry 67, n. 12 (1 gennaio 1995): 2109–48. http://dx.doi.org/10.1351/pac199567122109.

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39

Yang, Ting, Quanjiu Wang, Yanli Liu, Pengyu Zhang e Laosheng Wu. "A comparison of mathematical models for chemical transfer from soil to surface runoff with the impact of rain". CATENA 137 (febbraio 2016): 191–202. http://dx.doi.org/10.1016/j.catena.2015.09.014.

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40

López Machado, Nelson Andrés, Christian Gonzalo Domínguez Gonzalez, Wilmer Barreto, Néstor Méndez, Leonardo José López Machado, María Gabriela Soria Pugo, Ronnie Xavier Lizano Acevedo e Vanessa Viviana Montesinos Machado. "Rainwater storage in urban environments using green roofs". La Granja 32, n. 2 (28 agosto 2020): 54–71. http://dx.doi.org/10.17163/lgr.n32.2020.05.

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This article discusses the use of green roofs as rainfall water storage in its soil matrix. The methodology is analytical based on mathematical models, where runoff produced in an urban area is compared with current conditions of ordinary roofs with ceramic or bituminous materials as the original scenario, against another where green roofs are used. The study area is located in the Palavecino municipality of Lara state in Venezuela, in the flood zone of Quebrada Tabure. In this research, a quantitative comparison of the direct runoff hydrographs of the proposed scenarios was used, obtaining as a main result the reduction of runoff between 60% and 80% according to the period of return. An interesting point of this research was the incorporation of the routing of hydrographs on the roofs, reducing even more the peak flow over 90%, and delaying the peak time of the generated hydrographs between 10 and 12 minutes while the total duration of the hydrographs increase more than three times.

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Kukushkin, S. S., e O. E. Khromov. "Methods of simplifying mathematical measurement models by means of nontraditional finite-field theory". Measurement Techniques 50, n. 10 (ottobre 2007): 1028–34. http://dx.doi.org/10.1007/s11018-007-0191-3.

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42

Feng, Shide. "The Measurement of Capital Stock of China". E3S Web of Conferences 214 (2020): 01037. http://dx.doi.org/10.1051/e3sconf/202021401037.

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Capital stock is an important indicator in economics, it is an important indicator to measure the social and economic development status. But the research of capital stock is not wildly contributed. This paper is to measure capital stock and forecast future capital stock with time series models. The author conducts empirical methods based on the measurement methods of previous scholars. The paper concludes that the capital stock is growing stably, and with established new mathematical models and time series models, and combined with the latest data, measures the capital stock of China.

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Ranieri, Vittorio, Pasquale Colonna, John J. Sansalone e Alessio Sciddurlo. "Measurement of Hydraulic Conductivity in Porous Mixes". Transportation Research Record: Journal of the Transportation Research Board 2295, n. 1 (gennaio 2012): 1–10. http://dx.doi.org/10.3141/2295-01.

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In the past two decades, runoff-permeable porous pavement and porous friction courses of pavement systems have been implemented more frequently, first in Europe and subsequently in the United States. Consequently, research and case studies are increasing, with a commensurate increase in the knowledge base for these drainable pavement matrices and systems. The main distinguishing parameter of these porous matrices is the hydraulic conductivity (k), as compared with traditional impervious pavements. Equipment and standards for measuring k vary widely. This variability includes laboratory and field permeameters, constant-head and falling-head permeameters, and methods based on differing equipment and differing protocols. In many cases, such variability generates results that are either difficult to compare or not comparable. As a result, the value of k that is generated from different methods and different equipment is uncertain. The disparate methods and measurement of k as a parameter challenge the researcher and the practitioner. During the development and specifying phase, the researcher and the designer require a representative value of k to ensure proper predictive models and design. During and after construction, the engineer and the practitioner require k for quality control. This paper illustrates and summarizes the available methods for measuring the k of pavement porous mixes. Some case studies are examined to verify the differences between methods and equipment used for determination of k. The European Standard UNI EN 12697-19 is examined through an experimental study. Theoretical and practical results help explain the measurement of k for pavements as a primary parameter of porous runoff-permeable mixes.

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Dibike, Yonas B., e Paulin Coulibaly. "TDNN with logical values for hydrologic modeling in a cold and snowy climate". Journal of Hydroinformatics 10, n. 4 (1 ottobre 2008): 289–300. http://dx.doi.org/10.2166/hydro.2008.049.

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Watershed runoff in areas with heavy seasonal snow cover is usually estimated using physically based conceptual hydrologic models. Such simulation models normally require a snowmelt algorithm consisting of a surface energy balance and some accounting of internal snowpack processes to be part of the modeling system. On the other hand, artificial neural networks are flexible mathematical structures that are capable of identifying such complex nonlinear relationships between input and output datasets from historical precipitation, temperature and streamflow records. This paper presents the findings of a study on using a form of time-delayed neural network, namely time-lagged feedforward neural network (TLFN), that implicitly accounts for snow accumulation and snowmelt processes through the use of logical values and tapped delay lines. The logical values (in the form of symbolic inputs) are used to implicitly include seasonal information in the TLFN model. The proposed method has been successfully applied for improved precipitation–runoff modeling of both the Chute-du-Diable reservoir inflows and the Serpent River flows in northeastern Canada where river flows and reservoir inflows are highly influenced by seasonal snowmelt effects. The study demonstrates that the TLFN with logical values is capable of modeling the precipitation–runoff process in a cold and snowy climate by relying on ‘logical input values’ and tapped delay lines to implicitly recognize the temporal input–output patterns in the historical data. The study results also show that, once the appropriate input patterns are identified, the time-lagged neural network based models performed quite well, especially for spring peak flows, and demonstrated comparable performance in simulating the precipitation–runoff processes to that of a physically based hydrological model, namely HBV.

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Wang, Ze Hong, Yue Xin Han e Bing Chen Chen. "A Mathematical Model for Predicting the Internal Parameters of Ball Mill". Advanced Materials Research 454 (gennaio 2012): 151–56. http://dx.doi.org/10.4028/www.scientific.net/amr.454.151.

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The internal parameters of ball mill are very important in the grinding process and have significant impact on the grinding results. Accurate measurement of the internal parameters of ball mill is crucial and indispensable for optimization and control of grinding process. In this paper, a novel tri-sensor measurement method was used to measure the external signals (i.e., bearing pressure, sound intensity and power consumption) of ball mill. Mathematical models, which link the external signals of ball mill with its internal parameters, were established to predict the internal parameters of ball mill. Experimental results showed that the mathematical models could directly predict the internal parameters of ball mill once the external signals were obtained. The tri-sensor measurement method and the mathematical models proposed in this paper provided a new way and solid basis for optimization and control of ball milling.

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Agrawal, Ashish, Anil Kumar Kothari, Arun Kumar, Manish Kumar Singh, Shivendra Kumar Dubey, R. V. Ramna e Shambhu Nath. "Advances in thermal level measurement techniques using mathematical models, statistical models and decision support systems in blast furnace". Metallurgical Research & Technology 116, n. 4 (2019): 421. http://dx.doi.org/10.1051/metal/2019019.

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The estimation of thermal level in blast furnace is of utmost importance, because the processes occurring inside the blast furnace are complex in nature and any drift in thermal level could lead to abnormal furnace state. The present review is made to understand the methods for estimating thermal level in blast furnace, and the drift in estimation of the thermal level. The thermal level estimation is divided into 3 categories, viz. mathematical models, statistical models and decision support systems. The mathematical models are based on the first principle of thermodynamics and give an estimate of the thermal level in blast furnace. On the other hand, the statistical models are mainly the data-based approach that uses the historical data to predict the instability in blast furnace. Lastly, the decision support systems are the prescriptive models that give the recommendations for making the necessary corrections in the process parameters to avoid occurrence of abnormality in blast furnace. Further, the drifts in estimation of thermal level by these techniques are identified and recommendations are made to improve the accuracy of thermal level estimation. The recommendations to control thermal level in blast furnace are provided which when applied in the industrial blast furnace, can avoid the occurrence of catastrophic condition.

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Nesterov, Evgeni, Grigori Frumin, Pavel Egorov e Alexander Lyubimov. "Diffuse biogenic load from the catchment area of small watercourses". E3S Web of Conferences 169 (2020): 01006. http://dx.doi.org/10.1051/e3sconf/202016901006.

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The article systematizes information on quantitative parameters for assessing the modules of the background runoff of nutrients (total phosphorus and total nitrogen) with the catchment of rivers and lakes. A new approach proposed for estimating the modules of the background runoff of nutrients based on mathematical models. A methodology for calculating the modules of the background runoff of nutrients from the catchments of the rivers of the Baltic Sea basin developed. The study of the dependence of the trophic level of the water reservoir on the amount of phosphorus and nitrogen entering it led to the development of the so-called load concept, which is based on the idea of the existence of a quantitative relationship between the amount of phosphorus intake and the reaction of the reservoir. The maximum allowable export to the Gulf of Finland is 4860 t/year of total phosphorus and 106680 t/year of total nitrogen. These values significantly exceed the total load on the Novaya river from its catchment area: 0.072 t/year for total phosphorus and 0.066 t/year for total nitrogen.

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Carson, Ewart R. "Measurement, Models and Medicine: Computer Modelling in hEalth Care Delivery". Measurement and Control 26, n. 4 (giugno 1993): 105–8. http://dx.doi.org/10.1177/002029409302600403.

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Computational modelling is becoming of increasing importance in assisting with, and enhancing, the processes of decision-making in clinical medicine and in health care delivery, processes which depend upon the effective interpretation of data yielded by measurement practice. Using conceptual models of health care delivery, a framework can be established within which the role of specific computational modelling paradigms can be clearly identified. Some of the methodological issues which underpin computer modelling are considered across the range of realizations (mathematical, logical, statistical and graphical) that find application in the clinical and health care domains. Examples are given of both quantitative modelling and qualitative model-based reasoning as important adjuncts to measurement practice.

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Wang, Hong Bo, Ying Xue Yao e Yong Zhan Zhou. "Research on Measurement of Viscosity Based on Cylinder Rotation". Applied Mechanics and Materials 16-19 (ottobre 2009): 1030–32. http://dx.doi.org/10.4028/www.scientific.net/amm.16-19.1030.

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Value of viscosity of liquid at an arbitrary velocity is important in many manufacturing processes, method of rotation is used commonly to measure it at a scheduled velocity, but it is not convenient to measure it at an arbitrary velocity. A method based on cylinder rotation is presented in the paper and it is used to measure it at an arbitrary velocity. Derivation of mathematical models is executed and a simulation is carried in Matlab. Results show that the velocity of the cylinder in the liquid attenuates by exponential law and it is in accordance with mathematical models. Error analysis indicates that that the generation of them mainly results from unsuited velocity of cylinder, slippage between the cylinder and the liquid and misalignment between the cylinder and the cup.

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Chvatalova, Zuzana, e Iveta Simberova. "ECONOMIC PHENOMENA VIA MATHEMATICAL MODELLING IN MAPLE SYSTEM". Business, Management and Education 9, n. 2 (28 novembre 2011): 260–76. http://dx.doi.org/10.3846/bme.2011.18.

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Nowadays, economics utilizes more and more frequently quantitative methods. This is an important phenomenon in the process of education. The paper deals with application of the Maple system for on-line creation of mathematical models in economic sectors. Means of Maple represent an important challenge for application in practice or research – resolve specific problems, apply mathematical models in many science fields, create intelligent documents for the presentation of modelling and analyses with computations, visualizations, animations, simulations. The paper incorporates selected samples of models in Maple and indicates further fields of its practical using, e.g. for measurement of marketing activity effectiveness.

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