3,861 research outputs found
A physically-based approach for evaluating the hydraulic invariance in urban transformations
Transformation of urban areas satisfies hydraulic invariance (HI) if the maximum flow rate outgoing
the area stays unchanged. The HI can be respected by dimensioning appropriate water storage
volumes or low impact developments (LID) to balance the soil sealing and ground levelling effects.
In order to comply with HI, some Italian regional legislation and river basin authority provide for
the creation of storage tanks whose volume must be estimated through simple conceptual rainfallrunoff
models. In this work a physically based approach for evaluating HI is proposed. It is based on
interpolating the results from a large number of hydraulic simulations conducted using FullSWOF,
which is an open source code developed by the University of Orléans. In this software the shallow
water equations are solved using a finite volume scheme and friction laws and infiltration models
are included. Simulations have been carried out considering the effect of three properties of the
area, that is: the saturated hydraulic conductivity of soil, the slope of ground surface and the standard
deviation of ground elevation around the mean level. Using the results, interpolating laws for
the peak discharge and the critical rainfall duration as function of the three basin parameters have
been derived. A parametric hydrograph as a function of the basin parameters and rainfall duration
is defined and a HI evaluation method based on routing the parametric hydrograph is proposed.
The results from this approach have been compared with those from non-physically based methods
currently used, such as the direct rainfall approach and the linear reservoir approach. The comparison
shows that the difference between these conceptual methods with that one proposed here
is strongly dependent on the runoff coefficient value. It is also not possible to predict whether they
are conservative or not
Demand uncertainty In modelling WDS: scaling laws and scenario generation
Water distribution systems (WDS) are critical infrastructures that should be designed to work properly in different conditions. The design and management of WDS should take into account the uncertain nature of some system parameters affecting the overall reliability of these infrastructures. In this context, water demand represents the major source of uncertainty. Thus, uncertain demand should be either modelled as a stochastic process or characterized using statistical tools. In this paper, we extend to the 3rd and 4th order moments the analytical equations (namely scaling laws) expressing the dependency of the statistical moments of demand signals on the sampling time resolution and on the number of served users. Also, we describe how the probability density function (pdf) of the demand signal changes with both the increase of the user’s number and the sampling rate variation. With this aim, synthetic data and real indoor water demand data are used. The scaling laws of the water demand statistics are a powerful tool which allows us to incorporate the demand uncertainty in the optimization models for a sustainable management of WDS. Specifically, in the stochastic/robust optimization, solutions close to the optimum in different working conditions should be considered. Obviously, the results of these optimization models are strongly dependent on the conditions that are taken into consideration (i.e. the scenarios). Among the approaches for the definition of demand scenarios and their probability-weight of occurrence, the moment-matching method is based on matching a set of statistical properties, e.g. moments from the 1st (mean) to the 4th (kurtosis) order
Tabvla Asiae VII
Publication: [Agrippinensium Colonia?] : [Excudebat Petrus Keschedt?], [1597?]
Physical Description: 1 map ; 14 x 18 cm, on sheet 17 x 23 cm
Language: Latin
Cartographic Mathematical Data: Scale not given, (E 49°35ʹ--E 82°05ʹ/N 43°33ʹ--N 26°01ʹ).
Notes: Ptolemaic map covering central Asia, including the Persian Gulf, Caspian Sea, Iran, Afghanistan, Pakistan, and India.
Relief shown pictorially.
Uncolored.
Copper-plate map.
Verso is page 22 of an unidentified text in Latin, with heading: Asiae Tabvla VI.
Taken from an early edition of Giovanni Antonio Magini\u27s Ptolemy\u27s Geographia, tentatively identified as: Ptolemy. Geographiae vniuersae tum veteris, tum nouae abolutissimum opus, duobus voluminibus districtum. Agrippinensium Colonia : Excudebat Petrus Keschedt, 1597
CERTIFICATION REPORT: The certification of the mass fractions of PBDEs in Fish Tissue: ERM®-CE102
This report describes the production of ERM®-CE102, which is a fish tissue certified for the mass fraction of polybrominated diphenyl ethers (PBDEs) on a wet weight basis. This material was produced following ISO 17034:2016 and is certified in accordance with ISO Guide 35:2017.
The Certified Reference Material is a fish tissue homogenate prepared from wild Wels catfish (Silurus glanis) originating from the Flix reservoir of the Ebro river (Spain) and aquaculture rainbow trout (Oncorhynchus mykiss) sourced in Belgium. The fish fillets were cut, shock-frozen in liquid nitrogen and cryogenically milled. After a pre-cooking step, a step-wise mixing and homogenisation were carried out. The resulting material was filled into jars, autoclaved for sterilisation and labelled as ERM-CE102.
Between unit-homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2017 [2]. Within-unit homogeneity was quantified to determine the minimum sample intake.
The material was characterised by an interlaboratory comparison of laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outlier was eliminated on statistical grounds only.
Uncertainties of the certified values were calculated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity, instability and characterisation.
The material is intended for the quality control and assessment of method performance. As with any reference material, it can be used for establishing control charts or in validation studies. ERM-CE102 is available in glass jars with twist-off lids containing at least 40 g of fish paste. The minimum amount of sample to be used is 8 g.JRC.F.6-Reference Material
Hemodynamic investigation of the flow diverter treatment of intracranial aneurysm
Flow diverter stents (FDS) are increasingly used for the treatment of complex intracranial aneurysms such as fusiform, giant, or wide-neck aneurysms. The primary goal of these devices is to reconstruct the diseased vascular segment by diverting blood flow from the aneurysm. The resulting intra-aneurysmal flow reduction promotes progressive aneurysm thrombosis and healing of the disease. In the present study, a numerical investigation was performed for modeling blood flow inside a patient-specific intracranial aneurysm virtually treated with FDS. The aim of the study is to investigate the effects of FDS placement prior to the actual endovascular treatment and to compare the effectiveness of devices differing in porosity. Numerical simulations were performed under pulsatile flow conditions, taking into account the non-Newtonian behavior of blood. Two possible post-operative conditions with virtual stent deployment were simulated. Hemodynamic parameters were calculated and compared between the pre-operative (no stent placement) and post-operative (virtual stent placement) aneurysm models. FDS placement significantly reduced intra-aneurysmal flow velocity and increased the Relative Residence Time (RRT) on the aneurysm, thus promoting thrombus formation within the dilatation and aneurysm occlusion. The results highlighted an increase in the effectiveness of FDS as its porosity increased. The proposed analysis provides pre-operative knowledge on the impact of FDS on intracranial hemodynamics, allowing the selection of the most effective treatment for the specific patient
USING A.R.P. PROXIMAL SURVEY TO MAP CALCIC HORIZON DEPTH IN VINEYARDS
The investigation of spatial variability of soil water retention capacity and depth is essential for a
correct and economical planning of water supply of a vineyard. The advantage of measuring soil
electrical properties by proximal sensors is the ability to operate with mobile and non-destructive
tools, quicker than the traditional soil survey. A.R.P. (Automatic Resistivity Profiling) is a mobile soil
electrical resistivity (ER) mapping system conceived by Geocarta (Paris, France), and it is
comprised by a couple of transmitter sprocket-wheels, which inject current within the soil, and three
couples of receiver sprocket-wheels, which measure the voltage-drop at three different depths,
about 0-50, 0-100 and 0-170 cm. Ten vineyards of “Villa Albius” farm in Sicily region (southern
Italy) were chosen to carry out the A.R.P. survey, for a overall surface of 45 hectares. The
vineyards were located in a wide Plio-Pleistocene marine terrace, characterized by a few meters
level of calcarenite, overlying partially cemented by calcium carbonate yellow sands. During the
A.R.P. survey, 12 boreholes were described and sampled for the laboratory analysis and other 6
boreholes were carried out to validade the map. All soils showed a calcic horizon (Bk, BCk or Ck)
with the upper limit at variable depths. The depth of calcic horizon (Dk) of each boreholes resulted
significantly correlated to ER, especially with the ER0-100 (R2 = 0.83). Dk map was interpolated
using the regression kriging and validated by the boreholes (R2 = 0.71) and with a NDVI map of
the same vintage (R2 = 0.95)
USING WRB TO MAP THE SOIL SYSTEMS OF ITALY
Aim of this work was to test the 2010 version of the WRB soil classification for compilating a map
of the soil systems of Italy at 1:500,000 scale. The source of data was the national geodatabase
storing information on 1,414 Soil Typological Units (STUs). Though, basically, we followed WRB
criteria to prioritize soil qualifiers, however, it was necessary to work out an original methodology in
the map legend representation to reproduce the high variability inside each delineation meanwhile
avoiding any loss of information. Each map unit may represent a combination of three codominant
STUs at the most. Dominant STUs were assessed summing up the occurrence of STUs
in the Land Components (LCs) of every soil system, where each LC is a specific combination of
morphology, lithology and land cover. STUs were classified according to the WRB soil
classification system, at the third level, that is, reference soil group and first two qualifiers, when
possible. Since the large number of delineations, map units grouping was needed to make the map
more legible. Legend colours were organized according to soil regions groups firstly, then by
considering the highest level of soil classification, so resulting a nidificated legend. The map
showed 3,357 polygons and 704 map units. The most common STU were Calcaric Cambisols, by
far followed by Calcaric Regosols, Eutric Cambisols, Haplic Calcisols, Vertic Cambisols, Cutanic
Luvisols, Leptic Pheozems, Chromic Luvisols, Dystric Cambisols, Fluvic Cambisols, and others
STUs belonging to almost all the WRB soil references. Keywords: geodatabase, soil system
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