Validation of Instantaneous Velocities Measurements with ADV Equipment in Turbulent High Two-Phase Flows

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Pressure and velocity distributions in plunge pools

Presented at the Protections 2016: 2nd international seminar on dam protection against overtopping: concrete dams, embankment dams, levees, tailings dams held on 7th-9th September, 2016, at Colorado State University in Fort Collins, Colorado, USA. The increasing demand for dam and levee safety and flood protection has motivated new research and advancements and a greater need for cost-effective measures in overtopping protection as a solution for overtopping concerns at levees and dams. This seminar will bring together leading experts from practice, research, development, and implementation for two days of knowledge exchange followed by a technical tour of the Colorado State University Hydraulic Laboratory with overtopping flume and wave simulator. This seminar will focus on: Critical issues related to levees and dams; New developments and advanced tools; Overtopping protection systems; System design and performance; Applications and innovative solutions; Case histories of overtopping events; Physical modeling techniques and recent studies; and Numerical modeling methods.Includes bibliographical references.When dam overtopping produces rectangular free jets that discharge into plunge pool basins below the dam, the pressure and velocity distributions of the flow in the plunge pool must be estimated to evaluate potential scour that might destabilize the dam. The high turbulence and aeration phenomena that appear in falling jets and dissipation basins make it difficult to carry out studies based only on classical methodologies. This work addresses plunge pool flows, and compares numerical results against our own experiments. Instantaneous pressures, velocities and air entrainment were obtained with the use of piezoresistive transducers, Acoustic Doppler Velocimeter and optical fiber, respectively. Mean velocity field and turbulence kinetic energy profiles were determined. To identify the level of reliability of models, numerical simulations were carried out by using the "homogeneous" model of ANSYS CFX, together with different turbulence closures. The numerical results fall fairly close to the values measured in the laboratory, and with expressions for submerged hydraulic jumps and horizontal wall jets. The observations can be well predicted for horizontal velocities greater than 40% of the maximum velocity in each profile, and when the ratio of the water cushion depth to the jet thickness is lower than 20

Proposals of a procedure to asses Pollutographs. Application to Murcia's Combined Sewer Overflows (CSOs). Póster

Directives 91/271/EEC and 93/481/EEC set norms regarding the management of Combined Sewer Overflows. European Commission monitors the implementation status and implementation programmes. In fact, during the year 2019 all the utilities should be able to quantify the pollution spilled during storm events. And afterwards, plans have to be developed in order to reduce the impact of such events. In this paper, we proposed a method to estimate the transported pollution during events as well as to serve as a tool for developing plans to lessen the corresponding pollution. The procedure is divided into three steps: A. Periodical measurements of all relevant pollutants, e.g. total suspended solids and chemical oxygen demand, in wet and dry weather. Such pollutant “concentrations” are correlated with the turbidity, updating the relation among them [1]. B. Continuous measures of the turbidity. Turbidity is continously register in the sewer areas near overflow spillways. Turbidimeters are a very convenient equipment for this purpose [2]. Actually, it is reliable, its measures are very correlated with the total suspended solid concentration and its maintenance is easy. In this way, combining A. and B. turbidity measures provide us a real-time estimation of the pollutant concentration. on real time. C. Assesment of each catchment hydrograph. Depending on the available data, this step could be based on a design, a measured or a simulated hydrograph. In order to apply this methodology to Murcia’s Combined Sewer System, we have used simulated hydrographs based on real measured rainfall. Murcia’s utility has developed a calibrated SWMM model, and therefore, using the rainfall data, it is possible to estimate hydrographs for all the relevant points of the system. D. Estimation of each catchment pollutograph. Combining the pollutant concentration, estimated in the previous steps, with the hydrographs, we can asses how the mass of pollutants are transported. This information allows us to comply with EU Directives, but it will also be useful to design Murcia’s strategy to minimize environmental impacts

Evaluating energy recovery potential in Murcia's water supply system

Murcia is the 7th most populated city in Spain. Its water supply system is extensively monitored through a large number of pressure gauges and flow meters. Murcia’s water supply network is fed from distribution reservoirs at enough elevation to avoid needing pumping stations for most of the city districts. Hydraulic resources have been evaluated throughout the water supply system. Besides the pressure reducing valves, where the assessment is quite straight forward [1], District Metered Areas (DMA) inlets have been evaluated. In these areas despite the hydraulic resources are not as great as in pressure reducing valves locations, their location is quite convenient. Actually, these positions are located inside the city, therefore making easy to use the produced energy in municipal self consumption or to provide facilities to the citizens. In order to perform such evaluation, a detailed model of the water supply network has been implemented in EPANET parting from a GIS model. The first step of the evaluation has consisted in the optimizing and validation of the model. Initially, the model was reviewed by comparing pressure and flow rate measurements in the main pipes. Then, an extensive experimental campaign was designed. In that campaign valves were switched so that each day a set of District Metered Areas (DMA) have just one metered inlet or at the most a very short number of metered inlets, whereas having a set of pressure measurements within the DMA. The obtained data was used to minimize errors in pressure time series, optimising roughness of the main pipes through Levenberg/Marquardt BFGS algorithm using EPANET ToolKit through Epanet-Octave [2]. Important roughness proposed changes tended to be located surrounding particular points, where errors in the GIS were located (mainly wrong diameter assignement). After patching all the errors the algorithm eased to localise, model errors were mostly below measures uncertainty, and therefore, the model was considered validated. Then, the hydraulic potential at the DMAs inlets has been evaluated by tracking the “instantaneous” minimum pressure and head within each DMA, as well as the flow rate entering the DMA. So that, the maximum head and the range of flow rates is established for the turbine. At the moment, once that all of these potentials have been assessed, a turbine prototype is being designed

Experimental and computational study of conductivity of multilayer graphene in polypropylene nanocomposites

[EN] We study the electric conductivity of compounds formed by multilayer graphene in polypropylene. Our study makes a comparative analysis between the experimental and computational results. To obtain an experimental measurement of the electronic properties, we deposited multilayer graphene (MLG) nanoparticles over a polypropylene matrix. The deposition was made over several stages, in which we added to the polymer matrix different percentages of MLG nanoparticles using the melt compounding technique, and we studied the conductivities of the nanocomposites by means of electrochemical impedance spectroscopy (EIS). The second part consists of computational calculations, in which we studied the electronic properties of a graphene sheet under a polypropylene molecule with different slabs in the monomer. In both analyses, there is a strong percolation phenomenon with a percolation threshold of around 18% of the MLG nanoparticles. Before the percolation threshold, the charge carriers are constrained in the polypropylene molecule, making the system an insulating material and creating p-type doping. After the percolation threshold, the charge carriers are constrained in the graphene, making the system a conductor material and creating n-type doping with conductivity values of around 20 S m(-1). This phenomenon is a consequence of a change in the mechanism of charge transfer in the interface between the polypropylene molecule and graphene sheet. To describe the charge transfer mechanism, it is necessary to consider the quantum effect. The incorporation of the quantum effects and the percolation phenomenon make it possible for the theoretical conductivity to be close to the conductivity measured experimentally.This research has been supported by the ENE/2015-69203-R project, granted by the Ministerio de Economia y Competitividad (MINECO), Spain. Also, the authors are grateful to UNAM-DGAPA-PAPIIT projects IG 100618 y IG 114818, DGTIC-UNAM for access to the Miztli-UNAM supercomputer LANCAD-UNAM-DGTIC-055, and UNAM-DGAPA for the Postdoctoral grant for Roxana M. del Castillo.Del Castillo, RM.; Del Castillo, LF.; Calles, AG.; Compañ Moreno, V. (2018). Experimental and computational study of conductivity of multilayer graphene in polypropylene nanocomposites. Journal of Materials Chemistry C. 6:7232-7241. https://doi.org/10.1039/c8tc01135dS723272416H. G. Karian , Handbook of polypropylene and polypropylene composites , RheTec, Inc. , Whitmore Lake, Michigan , 2nd edn, 2003 , https://books.google.es/books?hl=es&lr=&id=C0nzeNPUpoIC&oi=fnd&pg=PP1&dq=Handbook+of+polypropylene+and+polypropylene+composites&ots=LYqYBYg45n&sig=3gtYXigr8_O8CUJeefBCtGI7QXA#v=onepage&q=Handbook%20of%20polypropylene%20and%20polypropylene%20composites&f=falseRath, T., & Li, Y. (2011). Nanocomposites based on polystyrene-b-poly(ethylene-r-butylene)-b-polystyrene and exfoliated graphite nanoplates: Effect of nanoplatelet loading on morphology and mechanical properties. Composites Part A: Applied Science and Manufacturing, 42(12), 1995-2002. doi:10.1016/j.compositesa.2011.09.002Kim, M.-S., Yan, J., Kang, K.-M., Joo, K.-H., Kang, Y.-J., & Ahn, S.-H. (2013). Soundproofing ability and mechanical properties of polypropylene/exfoliated graphite nanoplatelet/carbon nanotube (PP/xGnP/CNT) composite. International Journal of Precision Engineering and Manufacturing, 14(6), 1087-1092. doi:10.1007/s12541-013-0146-3Zhang, K., Yu, H.-O., Shi, Y.-D., Chen, Y.-F., Zeng, J.-B., Guo, J., … Wang, M. (2017). Morphological regulation improved electrical conductivity and electromagnetic interference shielding in poly(l-lactide)/poly(ε-caprolactone)/carbon nanotube nanocomposites via constructing stereocomplex crystallites. Journal of Materials Chemistry C, 5(11), 2807-2817. doi:10.1039/c7tc00389gMohd Radzuan, N. A., Yusuf Zakaria, M., Sulong, A. B., & Sahari, J. (2017). The effect of milled carbon fibre filler on electrical conductivity in highly conductive polymer composites. Composites Part B: Engineering, 110, 153-160. doi:10.1016/j.compositesb.2016.11.021Li, Q., Yao, F.-Z., Liu, Y., Zhang, G., Wang, H., & Wang, Q. (2018). High-Temperature Dielectric Materials for Electrical Energy Storage. Annual Review of Materials Research, 48(1), 219-243. doi:10.1146/annurev-matsci-070317-124435Qiao, Y., Yin, X., Zhu, T., Li, H., & Tang, C. (2018). Dielectric polymers with novel chemistry, compositions and architectures. Progress in Polymer Science, 80, 153-162. doi:10.1016/j.progpolymsci.2018.01.003Rosehr, A., & Luinstra, G. A. (2017). Polypropylene composites with finely dispersed multi-walled carbon nanotubes covered with an aluminum oxide shell. Polymer, 120, 164-175. doi:10.1016/j.polymer.2017.05.045Bolotin, K. I., Sikes, K. J., Jiang, Z., Klima, M., Fudenberg, G., Hone, J., … Stormer, H. L. (2008). Ultrahigh electron mobility in suspended graphene. Solid State Communications, 146(9-10), 351-355. doi:10.1016/j.ssc.2008.02.024Banszerus, L., Schmitz, M., Engels, S., Goldsche, M., Watanabe, K., Taniguchi, T., … Stampfer, C. (2016). Ballistic Transport Exceeding 28 μm in CVD Grown Graphene. Nano Letters, 16(2), 1387-1391. doi:10.1021/acs.nanolett.5b04840Terrés, B., Chizhova, L. A., Libisch, F., Peiro, J., Jörger, D., Engels, S., … Stampfer, C. (2016). Size quantization of Dirac fermions in graphene constrictions. Nature Communications, 7(1). doi:10.1038/ncomms11528Zhang, H.-B., Zheng, W.-G., Yan, Q., Yang, Y., Wang, J.-W., Lu, Z.-H., … Yu, Z.-Z. (2010). Electrically conductive polyethylene terephthalate/graphene nanocomposites prepared by melt compounding. Polymer, 51(5), 1191-1196. doi:10.1016/j.polymer.2010.01.027Chung, D. D. L. (2015). A review of exfoliated graphite. Journal of Materials Science, 51(1), 554-568. doi:10.1007/s10853-015-9284-6T. Bayerl , A.Benedito , A.Gallegos , G. B.Mitschang and B.Galindo , Melting of Polymer-Polymer Composites by Particulate Heating Promoters and Electromagnetic Radiation , in Synthetic Polymer-Polymer Composites , ed. D. Bhattacharyya and S. Fakirov , Carl HanserVerlag GmbH & Co. KG , 2012 , ch. 24, pp. 39–64 10.3139/9781569905258.002Harper, J., Price, D., & Zhang, J. (2005). Use of Fillers to Enable the Microwave Processing of Polyethylene. Journal of Microwave Power and Electromagnetic Energy, 40(4), 219-227. doi:10.1080/08327823.2005.11688543Galindo, B., Benedito, A., Gimenez, E., & Compañ, V. (2016). Comparative study between the microwave heating efficiency of carbon nanotubes versus multilayer graphene in polypropylene nanocomposites. Composites Part B: Engineering, 98, 330-338. doi:10.1016/j.compositesb.2016.04.082Asadi, K., Kronemeijer, A. J., Cramer, T., Jan Anton Koster, L., Blom, P. W. M., & de Leeuw, D. M. (2013). Polaron hopping mediated by nuclear tunnelling in semiconducting polymers at high carrier density. Nature Communications, 4(1). doi:10.1038/ncomms2708Fan, Z., Gong, F., Nguyen, S. T., & Duong, H. M. (2015). Advanced multifunctional graphene aerogel – Poly (methyl methacrylate) composites: Experiments and modeling. Carbon, 81, 396-404. doi:10.1016/j.carbon.2014.09.072Zabihi, Z., & Araghi, H. (2016). Monte Carlo simulations of effective electrical conductivity of graphene/poly(methyl methacrylate) nanocomposite: Landauer-Buttiker approach. Synthetic Metals, 217, 87-93. doi:10.1016/j.synthmet.2016.03.024Xia, X., Zhong, Z., & Weng, G. J. (2017). Maxwell–Wagner–Sillars mechanism in the frequency dependence of electrical conductivity and dielectric permittivity of graphene-polymer nanocomposites. Mechanics of Materials, 109, 42-50. doi:10.1016/j.mechmat.2017.03.014F. M. Bickelhaupt and E. J.Baerends , Kohn–Sham Density Functional Theory: Predicting and Understanding Chemistry . in Reviews in Computational Chemistry , 2007 , ed. K. B. Lipkowitz and B. Boyd Donald , John Wiley & Sons, Inc. , vol. 15, pp. 1–89 10.1002/9780470125922.ch1/summaryPerdew, J. P., Burke, K., & Ernzerhof, M. (1996). Generalized Gradient Approximation Made Simple. Physical Review Letters, 77(18), 3865-3868. doi:10.1103/physrevlett.77.3865Methfessel, M., & Paxton, A. T. (1989). High-precision sampling for Brillouin-zone integration in metals. Physical Review B, 40(6), 3616-3621. doi:10.1103/physrevb.40.3616Monkhorst, H. J., & Pack, J. D. (1976). Special points for Brillouin-zone integrations. Physical Review B, 13(12), 5188-5192. doi:10.1103/physrevb.13.5188Files: C.pbe-van_ak.UPF, H.pbe-van_ak.UPF, N.pbe-van_ak.UPF, and O.pbe-van_ak.UPF, http://www.quantum-espresso.orgVanderbilt, D. (1990). Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. Physical Review B, 41(11), 7892-7895. doi:10.1103/physrevb.41.7892Sørensen, T. S., & Compañ, V. (1995). Complex permittivity of a conducting, dielectric layer containing arbitrary binary Nernst–Planck electrolytes with applications to polymer films and cellulose acetate membranes. J. Chem. Soc., Faraday Trans., 91(23), 4235-4250. doi:10.1039/ft9959104235Drüschler, M., Huber, B., & Roling, B. (2011). On Capacitive Processes at the Interface between 1-Ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate and Au(111). The Journal of Physical Chemistry C, 115(14), 6802-6808. doi:10.1021/jp200395jSerghei, A., Tress, M., Sangoro, J. R., & Kremer, F. (2009). Electrode polarization and charge transport at solid interfaces. Physical Review B, 80(18). doi:10.1103/physrevb.80.184301F. Kremer and A.Schoenhals , Broadban Dielectric Spectroscopy , Springer , Berlin , 2003Coelho, R. (1983). Sur la relaxation d’une charge d’espace. Revue de Physique Appliquée, 18(3), 137-146. doi:10.1051/rphysap:01983001803013700Macdonald, J. R. (1953). Theory of ac Space-Charge Polarization Effects in Photoconductors, Semiconductors, and Electrolytes. Physical Review, 92(1), 4-17. doi:10.1103/physrev.92.4Klein, R. J., Zhang, S., Dou, S., Jones, B. H., Colby, R. H., & Runt, J. (2006). Modeling electrode polarization in dielectric spectroscopy: Ion mobility and mobile ion concentration of single-ion polymer electrolytes. The Journal of Chemical Physics, 124(14), 144903. doi:10.1063/1.2186638Greenhoe, B. M., Hassan, M. K., Wiggins, J. S., & Mauritz, K. A. (2016). Universal power law behavior of the AC conductivity versus frequency of agglomerate morphologies in conductive carbon nanotube-reinforced epoxy networks. Journal of Polymer Science Part B: Polymer Physics, 54(19), 1918-1923. doi:10.1002/polb.24121Novoselov, K. S. (2004). Electric Field Effect in Atomically Thin Carbon Films. Science, 306(5696), 666-669. doi:10.1126/science.1102896Del Castillo, R. M., & Sansores, L. E. (2015). Study of the electronic structure of Ag, Au, Pt and Pd clusters adsorption on graphene and their effect on conductivity. The European Physical Journal B, 88(10). doi:10.1140/epjb/e2015-60001-2Galpaya, D., Wang, M., Liu, M., Motta, N., Waclawik, E., & Yan, C. (2012). Recent Advances in Fabrication and Characterization of Graphene-Polymer Nanocomposites. Graphene, 01(02), 30-49. doi:10.4236/graphene.2012.12005I. Zvyagin . Charge Transport via Delocalized States in Disordered Materials . in Charge Transport in Disordered Solids with Applications in Electronics , ed. S. Baranovsky , John Wiley & Sons, Inc. , 2006 , pp. 1–48 10.1002/0470095067.ch1/summaryLeenaerts, O., Partoens, B., & Peeters, F. M. (2009). Adsorption of small molecules on graphene. Microelectronics Journal, 40(4-5), 860-862. doi:10.1016/j.mejo.2008.11.022Hashemi, R., & Weng, G. J. (2016). A theoretical treatment of graphene nanocomposites with percolation threshold, tunneling-assisted conductivity and microcapacitor effect in AC and DC electrical settings. Carbon, 96, 474-490. doi:10.1016/j.carbon.2015.09.103Xia, X., Wang, Y., Zhong, Z., & Weng, G. J. (2017). A frequency-dependent theory of electrical conductivity and dielectric permittivity for graphene-polymer nanocomposites. Carbon, 111, 221-230. doi:10.1016/j.carbon.2016.09.078The determination of the elastic field of an ellipsoidal inclusion, and related problems. (1957). Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 241(1226), 376-396. doi:10.1098/rspa.1957.0133Trotta, S., Marmo, F., & Rosati, L. (2017). Evaluation of the Eshelby tensor for polygonal inclusions. Composites Part B: Engineering, 115, 170-181. doi:10.1016/j.compositesb.2016.10.018L. D. Landau , E. M.Lifshitz and L. P.Pitaevskii , Electrodynamics of Continuous Media , Pergamon Press , New York , 3rd edn, 1984Wang, Y., Weng, G. J., Meguid, S. A., & Hamouda, A. M. (2014). A continuum model with a percolation threshold and tunneling-assisted interfacial conductivity for carbon nanotube-based nanocomposites. Journal of Applied Physics, 115(19), 193706. doi:10.1063/1.4878195Wang, Y., Shan, J. W., & Weng, G. J. (2015). Percolation threshold and electrical conductivity of graphene-based nanocomposites with filler agglomeration and interfacial tunneling. Journal of Applied Physics, 118(6), 065101. doi:10.1063/1.4928293Wehling, T. O., Yuan, S., Lichtenstein, A. I., Geim, A. K., & Katsnelson, M. I. (2010). Resonant Scattering by Realistic Impurities in Graphene. Physical Review Letters, 105(5). doi:10.1103/physrevlett.105.056802Stauber, T., Peres, N. M. R., & Guinea, F. (2007). Electronic transport in graphene: A semiclassical approach including midgap states. Physical Review B, 76(20). doi:10.1103/physrevb.76.205423R. M. Del Castillo and L. E.Sansores . Adsorption of Metal Clusters on Graphene and Their Effect on the Electrical Conductivity , in Graphene Materials – Advanced Applications , ed. G. Z. Kyzas and A. C. Mitropoulos , INTECH , 2017 , https://www.intechopen.com/books/graphene-materials-advanced-applications/adsorption-of-metal-clusters-on-graphene-and-their-effect-on-the-electrical-conductivit

Aerated jets and pressure fluctuation in plunge pools

Proceedings of the Seventh International Conference on Hydroscience and Engineering, Philadelphia, PA, September 2006. http://hdl.handle.net/1860/732In this paper are presented the principal results of a theoretical analysis and revaluation of experimental data corresponding to different investigation about mean and fluctuating dynamic pressure in plunge pools. These results are discussed and compared with the case of circular jets and it is demonstrated that knowledge of the falling jet process is of crucial importance for the characterization of the downstream physical phenomena. Thus, observations and formulae are proposed in the following subjects: initial jet turbulence intensity Tu, jet break-up length Lb, impingement jet thickness Bj, mean dynamic pressure coefficient Cp and fluctuating dynamic pressure coefficient C´p. Some examples are provided to demonstrate how the findings may be used in practice and also like a verification of the proposed methodology

Endometrial blood flow mapping using transvaginal power Doppler sonography in women with postmenopausal bleeding and thickened endometrium

Objective To evaluate the role of transvaginal power Doppler sonography to discriminate between benign and malignant endometrial conditions in women presenting with postmenopausal bleeding and thickened endometrium at baseline sonography. Methods Ninety-one postmenopausal women (median age, 58 years; range, 47–83 years) presenting with uterine bleeding and a thickened endometrium (≥5-mm doublelayer endometrial thickness) on transvaginal sonography were included in this prospective study. Endometrial blood flow distribution was assessed in all patients by power Doppler immediately after B-mode transvaginal sonography. Three different vascular patterns were defined: Pattern A: multiple-vessel pattern, Pattern B: single-vessel pattern and Pattern C: scattered-vessel pattern. Histological diagnoses were obtained in all cases. No patient taking tamoxifen citrate or receiving hormone replacement therapy was included. Results Histological diagnoses were as follows: endometrial cancer: 33 (36%), endometrial polyp: 37 (41%), endometrial hyperplasia: 14 (15%), endometrial cystic atrophy: 7 (8%). Blood flow was found in 97%, 92%, 79% and 85% of cases of carcinoma, polyp, hyperplasia and endometrial cystic atrophy, respectively. A total of 81.3% of vascularized endometrial cancers showed Pattern A, 97.1% of vascularized polyps exhibited Pattern B and 72.7% of vascularized hyperplasias showed Pattern C. Sensitivity and specificity for endometrial cancer were 78.8% and 100%. For endometrial polyp these respective values were 89.2% and 87% and for hyperplasia they were 57.1% and 88.3%. Conclusions Transvaginal power Doppler blood flow mapping is useful to differentiate benign from malignant endometrial pathology in women presenting with postmenopausal bleeding and thickened endometrium at baseline sonography

Numerical Simulations And Laboratory Measurements In Hydraulic Jumps

Hydraulic jump is one of the most extended and effective mechanism for hydraulic energy dissipation. Usually, hydraulic jump characteristics have been studied through physical models. Nowadays, computational fluid dynamics (CFD) are an important tool that can help to analyze and to understand complex phenomena that involve high turbulence and air entrainment cases. Free and submerged hydraulic jumps with Froude numbers from 2.9 to 5.5 are studied in a rectangular channel downstream a sluice gate. Velocity measurements with different flow rates are carried out by using Acoustic Doppler Velocimeter (ADV) and Particle Image Velocimeter (PIV) instrumentations. In this paper, laboratory measurements are used to calibrate and to validate open source and commercial CFD programs. Air-water two-phase flows are considered in the simulations. The closure problem is solved by using different turbulence models. Water depths, hydraulic jumps lengths, velocity profiles and energy dissipation rates are compared with laboratory measurements and other referenced results

Estimating of bootstrap confidence intervals for freight transport matrices

Freight transport studies require, as a preliminary step, a survey to be conducted on a sample of the universe of agents, vehicles and/or companies of the transportation system. The statistical reliability of the data determines the goodness of the outcomes and conclusions that can be inferred from the analyses and models generated. The methodology contained herein, based on bootstrapping techniques, allows us to generate the confidence intervals of origin-destination pairs defined by each cell of the matrix derived from a freight transport survey. To address this study a data set from a statistically reliable freight transport study conducted in Spain at the level of multi-province inter-regions has been used.Public Road Agency of the Andalusian Regional Government (AOP-JA, Spain Project G-GI3000/IDII)EU FEDE