ABSTRACT The aim of this study is to test the utilization of Landsat TM-5 imagery in hydrological... more ABSTRACT The aim of this study is to test the utilization of Landsat TM-5 imagery in hydrological applications. The areas selected for the study are the: Nievole river basin (47 km2), a subcatchment of the Arno river basin (Toscana, Italy) and the Fucecchio marsh (50 km2 , Toscana, Italy). A linear relationship has been found between satellite data and soil parameters obtained from pedological maps available: fur the marsh area, such as hydraulic conductivity (K, mm/h) and soil water content (WC, mm). An example of obtaining runoff Curve Number, CN, is also presented. The same relation has been used for the hydraulic characterization of the Nievole river basin, marked by lack of pedologic maps. The procedure described in the article provides an accurate soil hydraulic characterization based on remote sensing for areas where soil maps are too expensive and time consuming to realize
Abstract Pore sizes and distribution in ultrafiltration membranes represent important parameters ... more Abstract Pore sizes and distribution in ultrafiltration membranes represent important parameters in the evaluation of the performances of a given membrane. At present, no standard procedure exists for this purpose. For membrane production as well as for ultrafiltration procedures the case of pore analysis is an important achievement for both performance control and materials characterization. For this purpose, a new apparatus has been realized and accurately set up. It is based on the combined principles of bubble pressure and solvent permeability, which allow a quick and precise measurement by means of a dedicated automatic instrument. In this work all relevant details concerning the procedure used, as well as the automatic instrumentation developed and the most relevant information on porosimetry obtainable are presented and discussed.
Skin layer porosity of ultrafiltration membranes was evaluated by an instrument based on the comb... more Skin layer porosity of ultrafiltration membranes was evaluated by an instrument based on the combined bubble pressure and solvent permeability methods. Nuclepore membranes were first tested for calibration and reproducibility purposes. Measurements were then carried out both on membranes prepared in our labs and an commercial ones. Porosity results are discussed in relation to membrane preparation variables as well as to phenomena controlling membrane performance during ultrafiltration application.
This article presents the experimental results obtained from a Froude model of flow between bridg... more This article presents the experimental results obtained from a Froude model of flow between bridge piers, semi-circular in front, for a moderately fast uniform current. The tests highlighted a hysteresis phenomenon relative to the energy limit of the transition flow across the critical state, which indicated the need for limit values higher than those obtained from a theoretical analysis of the energy behavior. An attempt is made to interpret the scale effects on the maximum water height in front of the piers, and the maximum level reached under the bridge. /TRRL/
This communication deals with the needs for improving the general knowledge in hydrological scien... more This communication deals with the needs for improving the general knowledge in hydrological sciences. In particular a special effort is devoted to define the concept of “entropy” as function of the knowledge, and to derive some simple reference ideas in order to analyze the general problem of the hydrological knowledge.
ABSTRACT Sommario Allo scopo di ricercare i limiti del campo di integrazione dell'equazio... more ABSTRACT Sommario Allo scopo di ricercare i limiti del campo di integrazione dell'equazione differenziale del moto per le correnti a pelo libero si completa la forma classica tramite l'introduzione di alcuni termini, raramente utilizzati nella pratica, ma parzialmente già introdotti da altri Autori.
The artificial neural network technique is experimented to cope with the study of the sub-annual ... more The artificial neural network technique is experimented to cope with the study of the sub-annual seasonal non-stationarity of the rainfall process. The homogeneity of the climatic signals inside each of the natural 12 monthly classes is analyzed, adopting a multilayer feed-forward network with error back-propagation. The possibility of identifying 'monthly based seasons' from only daily rainfall data is found to be quite limited. The coupling of rainfall and temperature statistics is instead confirmed to be a fundamental climatic indicator. Contrary to what is commonly expected, the season uncertainty appears higher in summer and in winter than in spring or autumn. The hypothesis of defining any monthly based pluviometric regime is however demonstrated to be generally difficult to sustain, revealing the necessity of adopting an unsupervised criterion to identify any seasonal filter of the rainfall process. Sommario. Viene sperimentata la tecnica delle reti neurali artificiali per affrontare lo studio della non-stazionarit~ stagionale del processo di precipitazione. Viene analizzata l'omogeneit~ dei segnali climatici all'intemo di ciascuna delle 12 naturali classi mensili, adottando un rete di tipo multistrato 'feed-forward' con retro-propagazione dell'errore. La possibilit~t di indentificare le stagioni su base mensile con i soli dati di precipitazione si dimostra essere piuttosto limitata. Viceversa, l'accoppiamento fra le statistiche di pioggia e temperatura si rivela essere un fondamentale indicatore climatico. AI contrario di quanto comunemente reputato, l'incertezza nella stagionalit~ appare essere pifi alta in estate ed in invemo che in primavera e in autunno. L'ipotesi sulla definizione su base mensile dei regimi pluviometrici appare comunque difficile da sostenere, rivelando la necessit~ di adottare un criterio senza supervisione per l'identificazione del filtro stagionale relativo al processo di precipitazione.
The ultrafiltration of orange and lemon juices has been investigated on a pilot-plant scale at co... more The ultrafiltration of orange and lemon juices has been investigated on a pilot-plant scale at constant concentration using tubular configuration polymeric and ceramic membranes. The permeate fluxes were found to be strongly dependent on the tangential feed velocity at the membrane but almost independent of the driving force at average pressures over the membrane greater than = 0.2 MPa. These results are due to the formation of a pectin-pulp deposit on the membrane, which effectively controls the ultrafiltration. Because of their different st@ace structures and roughness this deposit has different properties for the ceramic and polymeric membranes. This causes the latter to behave as rough tubes. The ceramic membranes give higher permeate fluxes at a lower Reynolds number than the polymeric membranes. This and their smooth tube behaviour indicate the possibility of greater energy eficiency for the industrial application of the ceramic than of the polymeric membranes. 473
Journal of Computing in Civil Engineering, Jul 1, 1997
ABSTRACT A software environment for real-time flood forecasting using distributed models is prese... more ABSTRACT A software environment for real-time flood forecasting using distributed models is presented. The system, Real-time Interactive Basin Simulator (RIBS), provides an object-oriented framework for implementation of a class of distributed rainfall-runoff models satisfying certain formal requirements, live test models have been implemented within the system, allowing easy comparison of model performance under equal circumstances. RIBS manages process organization and data handling; facilitation of user interaction and result visualization and provision of access to model structure, hydrologic processes, and model inference, In this paper, software architecture is discussed, focusing on data representation, object organization, model inference, and interactive features of the graphic user interface.
SOMMARIO : Reeen/i risultati sperimenlali hanno evidenzialo l'influenza degli effetti della visco... more SOMMARIO : Reeen/i risultati sperimenlali hanno evidenzialo l'influenza degli effetti della viscosita superficiale in correnti di ]abora/orio e di conseguenza l'importanza di poter conh'ollare tale grandezza lramile tell misuratore. Parlendo dalle leorie esislenti si formula un sistema eli equazioni differenziali /a cui soluzione numerica ~ confrontata con risultati analitici di altri AulorL In ultimo si presenta ]a proposta eli un misuratore di viscosith superficiale che rich&de solo misure di tipo cinematico.
Ce travail entend analyser, avec l'emploi d’un modèle hydrologique distribué, la situation hy... more Ce travail entend analyser, avec l'emploi d’un modèle hydrologique distribué, la situation hydro-météorologique que produit l'événement de l'Octobre 1992 en un bassin versant d'environ 48 km2 dan la banlieue de la Ville de Florence, basin de la Rivière Amo en Italie. Le modèle de calcul adopté est entendu à simuler les caractéristiques du sol e des réseaux hydrologique sous ces précipitations. La répartition spatiale ainsi que temporal des pluies a été dérivée de mesures RADAR et de données ponctuelles. Aussi que la structure du modèle hydrologique adopté, on examine l’interpolation des mesures pluviométriques sur la base des images du radar avec des fonctionnes de corrélation ; aussi que la reconstruction de l'évolution dynamique du champ de précipitation dans les temps. Les résultats des calculs du modèle distribué sont comparer avec les témoignages directs.Becchi I., Caporali E., Castellani L., Castelli F. 23. - Le contrôle hydrologique des crues soudaines : le cas de Florence. In: Crues et inondations. 23èmes journées de l'hydraulique. Congrès de la Société Hydrotechnique de France. Nimes (France), 14-15-16 septembre 1994. Tome 2, 1994
ABSTRACT The aim of this study is to test the utilization of Landsat TM-5 imagery in hydrological... more ABSTRACT The aim of this study is to test the utilization of Landsat TM-5 imagery in hydrological applications. The areas selected for the study are the: Nievole river basin (47 km2), a subcatchment of the Arno river basin (Toscana, Italy) and the Fucecchio marsh (50 km2 , Toscana, Italy). A linear relationship has been found between satellite data and soil parameters obtained from pedological maps available: fur the marsh area, such as hydraulic conductivity (K, mm/h) and soil water content (WC, mm). An example of obtaining runoff Curve Number, CN, is also presented. The same relation has been used for the hydraulic characterization of the Nievole river basin, marked by lack of pedologic maps. The procedure described in the article provides an accurate soil hydraulic characterization based on remote sensing for areas where soil maps are too expensive and time consuming to realize
Abstract Pore sizes and distribution in ultrafiltration membranes represent important parameters ... more Abstract Pore sizes and distribution in ultrafiltration membranes represent important parameters in the evaluation of the performances of a given membrane. At present, no standard procedure exists for this purpose. For membrane production as well as for ultrafiltration procedures the case of pore analysis is an important achievement for both performance control and materials characterization. For this purpose, a new apparatus has been realized and accurately set up. It is based on the combined principles of bubble pressure and solvent permeability, which allow a quick and precise measurement by means of a dedicated automatic instrument. In this work all relevant details concerning the procedure used, as well as the automatic instrumentation developed and the most relevant information on porosimetry obtainable are presented and discussed.
Skin layer porosity of ultrafiltration membranes was evaluated by an instrument based on the comb... more Skin layer porosity of ultrafiltration membranes was evaluated by an instrument based on the combined bubble pressure and solvent permeability methods. Nuclepore membranes were first tested for calibration and reproducibility purposes. Measurements were then carried out both on membranes prepared in our labs and an commercial ones. Porosity results are discussed in relation to membrane preparation variables as well as to phenomena controlling membrane performance during ultrafiltration application.
This article presents the experimental results obtained from a Froude model of flow between bridg... more This article presents the experimental results obtained from a Froude model of flow between bridge piers, semi-circular in front, for a moderately fast uniform current. The tests highlighted a hysteresis phenomenon relative to the energy limit of the transition flow across the critical state, which indicated the need for limit values higher than those obtained from a theoretical analysis of the energy behavior. An attempt is made to interpret the scale effects on the maximum water height in front of the piers, and the maximum level reached under the bridge. /TRRL/
This communication deals with the needs for improving the general knowledge in hydrological scien... more This communication deals with the needs for improving the general knowledge in hydrological sciences. In particular a special effort is devoted to define the concept of “entropy” as function of the knowledge, and to derive some simple reference ideas in order to analyze the general problem of the hydrological knowledge.
ABSTRACT Sommario Allo scopo di ricercare i limiti del campo di integrazione dell'equazio... more ABSTRACT Sommario Allo scopo di ricercare i limiti del campo di integrazione dell'equazione differenziale del moto per le correnti a pelo libero si completa la forma classica tramite l'introduzione di alcuni termini, raramente utilizzati nella pratica, ma parzialmente già introdotti da altri Autori.
The artificial neural network technique is experimented to cope with the study of the sub-annual ... more The artificial neural network technique is experimented to cope with the study of the sub-annual seasonal non-stationarity of the rainfall process. The homogeneity of the climatic signals inside each of the natural 12 monthly classes is analyzed, adopting a multilayer feed-forward network with error back-propagation. The possibility of identifying 'monthly based seasons' from only daily rainfall data is found to be quite limited. The coupling of rainfall and temperature statistics is instead confirmed to be a fundamental climatic indicator. Contrary to what is commonly expected, the season uncertainty appears higher in summer and in winter than in spring or autumn. The hypothesis of defining any monthly based pluviometric regime is however demonstrated to be generally difficult to sustain, revealing the necessity of adopting an unsupervised criterion to identify any seasonal filter of the rainfall process. Sommario. Viene sperimentata la tecnica delle reti neurali artificiali per affrontare lo studio della non-stazionarit~ stagionale del processo di precipitazione. Viene analizzata l'omogeneit~ dei segnali climatici all'intemo di ciascuna delle 12 naturali classi mensili, adottando un rete di tipo multistrato 'feed-forward' con retro-propagazione dell'errore. La possibilit~t di indentificare le stagioni su base mensile con i soli dati di precipitazione si dimostra essere piuttosto limitata. Viceversa, l'accoppiamento fra le statistiche di pioggia e temperatura si rivela essere un fondamentale indicatore climatico. AI contrario di quanto comunemente reputato, l'incertezza nella stagionalit~ appare essere pifi alta in estate ed in invemo che in primavera e in autunno. L'ipotesi sulla definizione su base mensile dei regimi pluviometrici appare comunque difficile da sostenere, rivelando la necessit~ di adottare un criterio senza supervisione per l'identificazione del filtro stagionale relativo al processo di precipitazione.
The ultrafiltration of orange and lemon juices has been investigated on a pilot-plant scale at co... more The ultrafiltration of orange and lemon juices has been investigated on a pilot-plant scale at constant concentration using tubular configuration polymeric and ceramic membranes. The permeate fluxes were found to be strongly dependent on the tangential feed velocity at the membrane but almost independent of the driving force at average pressures over the membrane greater than = 0.2 MPa. These results are due to the formation of a pectin-pulp deposit on the membrane, which effectively controls the ultrafiltration. Because of their different st@ace structures and roughness this deposit has different properties for the ceramic and polymeric membranes. This causes the latter to behave as rough tubes. The ceramic membranes give higher permeate fluxes at a lower Reynolds number than the polymeric membranes. This and their smooth tube behaviour indicate the possibility of greater energy eficiency for the industrial application of the ceramic than of the polymeric membranes. 473
Journal of Computing in Civil Engineering, Jul 1, 1997
ABSTRACT A software environment for real-time flood forecasting using distributed models is prese... more ABSTRACT A software environment for real-time flood forecasting using distributed models is presented. The system, Real-time Interactive Basin Simulator (RIBS), provides an object-oriented framework for implementation of a class of distributed rainfall-runoff models satisfying certain formal requirements, live test models have been implemented within the system, allowing easy comparison of model performance under equal circumstances. RIBS manages process organization and data handling; facilitation of user interaction and result visualization and provision of access to model structure, hydrologic processes, and model inference, In this paper, software architecture is discussed, focusing on data representation, object organization, model inference, and interactive features of the graphic user interface.
SOMMARIO : Reeen/i risultati sperimenlali hanno evidenzialo l'influenza degli effetti della visco... more SOMMARIO : Reeen/i risultati sperimenlali hanno evidenzialo l'influenza degli effetti della viscosita superficiale in correnti di ]abora/orio e di conseguenza l'importanza di poter conh'ollare tale grandezza lramile tell misuratore. Parlendo dalle leorie esislenti si formula un sistema eli equazioni differenziali /a cui soluzione numerica ~ confrontata con risultati analitici di altri AulorL In ultimo si presenta ]a proposta eli un misuratore di viscosith superficiale che rich&de solo misure di tipo cinematico.
Ce travail entend analyser, avec l'emploi d’un modèle hydrologique distribué, la situation hy... more Ce travail entend analyser, avec l'emploi d’un modèle hydrologique distribué, la situation hydro-météorologique que produit l'événement de l'Octobre 1992 en un bassin versant d'environ 48 km2 dan la banlieue de la Ville de Florence, basin de la Rivière Amo en Italie. Le modèle de calcul adopté est entendu à simuler les caractéristiques du sol e des réseaux hydrologique sous ces précipitations. La répartition spatiale ainsi que temporal des pluies a été dérivée de mesures RADAR et de données ponctuelles. Aussi que la structure du modèle hydrologique adopté, on examine l’interpolation des mesures pluviométriques sur la base des images du radar avec des fonctionnes de corrélation ; aussi que la reconstruction de l'évolution dynamique du champ de précipitation dans les temps. Les résultats des calculs du modèle distribué sont comparer avec les témoignages directs.Becchi I., Caporali E., Castellani L., Castelli F. 23. - Le contrôle hydrologique des crues soudaines : le cas de Florence. In: Crues et inondations. 23èmes journées de l'hydraulique. Congrès de la Société Hydrotechnique de France. Nimes (France), 14-15-16 septembre 1994. Tome 2, 1994
Uploads
Papers by Ignazio Becchi