Estimation of synthetic flood design hydrographs using a distributed rainfall–runoff model coupled with a copula-based single storm rainfall generator

In this paper a procedure to derive synthetic flood design hydrographs (SFDH) using a bivariate representation of rainfall forcing (rainfall duration and intensity) via copulas, which describes and models the correlation between two variables independently of the marginal laws involved, coupled with a distributed rainfall–runoff model, is presented. Rainfall–runoff modelling (R–R modelling) for estimating the hydrological response at the outlet of a catchment was performed by using a conceptual fully distributed procedure based on the Soil Conservation Service – Curve Number method as an excess rainfall model and on a distributed unit hydrograph with climatic dependencies for the flow routing. Travel time computation, based on the distributed unit hydrograph definition, was performed by implementing a procedure based on flow paths, determined from a digital elevation model (DEM) and roughness parameters obtained from distributed geographical information. In order to estimate the primary return period of the SFDH, which provides the probability of occurrence of a hydrograph flood, peaks and flow volumes obtained through R–R modelling were treated statistically using copulas. Finally, the shapes of hydrographs have been generated on the basis of historically significant flood events, via cluster analysis. <br><br> An application of the procedure described above has been carried out and results presented for the case study of the Imera catchment in Sicily, Italy

Supercapacitors based on AC/MnO2 deposited onto dip-coated carbon nanofiber cotton fabric electrodes

This work introduces the preparation of flexible carbon composite electrodes based on the top-down approach starting from the dip-coating of carbon nanofibers (CNFs) onto a cotton fabric. On these so-obtained conductive cotton fabrics, further layers of activated carbon and manganese oxide (MnO2) materials were subsequently added to enhance the electrochemical performances of negative and positive electrodes. At the end, two different types of asymmetric supercapacitors (SCs) were assembled with those textile electrodes by using porous paper and Nafion-Na ion-exchange membranes as separators. The different SCs were electrochemically characterized by means of cyclic voltammetry (CV), galvanostatic charge/discharge (G–CD) and electrochemical impedance spectroscopy (EIS). These hybrid carbon-based textile SCs exhibited capacitance performance of 138 and 134 F g–1 with the porous paper and Nafion membrane, respectively, and low self-discharge rates. Furthermore, in this study is considered the combination of two methods (cycling and floating) for studying the long-term durability tests of SCs. In particular, the floating methodology utilizes much more harsh conditions than the common cycling based on G-CD tests at high currents usually discussed in literature. The solid-state (Nafion membrane) hybrid device demonstrated very long durability with 10 K cycles and additional 270 h at a constant voltage of 1.6 V. In summary, the hybrid SCs fabricated with low cost materials and simple methodologies reported in this study showed very promising results for flexible energy storage applications.This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology (project POCI-01-0145-FEDER-007136). A.J. Paleo acknowledges the European COST Action CA15107- Multi-Functional Nano-Carbon Composite Materials Network (MultiComp) for its support with a Short Term Scientific Mission (STSM) grant at CNR-ITAE of Messina

Development of carbon/MnO₂ coated on nanofiber textile electrodes for hybrid solid-state supercapacitors

This work is focused on the design and development of hybrid solid-state energy storage devices with high capacitive performance. In particular, the work includes, the preparation of carbon composite electrodes based on a carbon nanofibers (CNF) supported on a cotton fabric. The coating of CNF to the cotton cloth is obtained by the dip and dry method. On these so-obtained composite substrates, further layers of activated carbon (Norit A Supra Eur) and manganese oxide (MnO2) material have been subsequenlty deposited to enhance the electrochemical performances of negative and positive electrodes, respectively. The preparation of carbon-based active layers comprises the spreading on the negative CNF-substrate of a slurry containing the activated carbon (AC) material, graphite fibres and polyvinylidene difluoride (PVDF) in N,N dimethylacetamide (DMA). Whereas the positive electrode is prepared by spreading a slurry of MnO2, carbon black, graphite fibers, PVDF in DMA. A 1M Na2SO4 solution impregnated in the porous paper separator (Nippon Kodoshi Corportion, Japan) and a polymer electrolyte membrane (Nafion 115) have been employed as electrolytes. The different supercapacitors were electrochemically characterized by cyclic voltammetry (CV), galvanostatic charge/discharge (G–CD), electrochemical impedance spectroscopy (EIS) and long-term cycling stability tests. The hybrid carbon-based textile supercapacitors exhibited capacitance performance of 137 and 120 F/g with the porous separator and Nafion 115 membrane, respectively. Specially, the solid-state (Nafion membrane) hybrid device demonstrated very long stability in cycling (10000 cycles) and holding voltage condition at 1.6 V (more than 200 h). Besides, these textile-based capacitors also showed really slow self-discharge.info:eu-repo/semantics/publishedVersio

Carbon and MnO₂ materials on carbon nanofibers cotton textile substrate for hybrid solid-state supercapacitors

This work is focused on the design and development of hybrid solid-state energy storage devices with high capacitive performance. In particular, the work includes, the preparation of carbon composite electrodes based on a carbon nanofibers (CNF) supported on a cotton fabric. The coating of CNF to the cotton cloth is obtained by the dip and dry method. On these so-obtained composite substrates, further layers of activated carbon (Norit A Supra Eur) and manganese oxide (MnO2) material have been subsequenlty deposited to enhance the electrochemical performances of negative and positive electrodes, respectively. The preparation of carbon-based active layers comprises the spreading on the negative CNF-substrate of a slurry containing the activated carbon (AC) material, graphite fibres and polyvinylidene difluoride (PVDF) in N,N dimethylacetamide (DMA). Whereas the positive electrode is prepared by spreading a slurry of MnO2, carbon black, graphite fibers, PVDF in DMA. A 1M Na2SO4 solution impregnated in the porous paper separator (Nippon Kodoshi Corportion, Japan) and a polymer electrolyte membrane (Nafion 115) have been employed as electrolytes. The different supercapacitors were electrochemically characterized by cyclic voltammetry (CV), galvanostatic charge/discharge (G–CD), electrochemical impedance spectroscopy (EIS) and long-term cycling stability tests. The hybrid carbon-based textile supercapacitors exhibited capacitance performance of 137 and 120 F/g with the porous separator and Nafion 115 membrane, respectively. Specially, the solid-state (Nafion membrane) hybrid device demonstrated very long stability in cycling (10000 cycles) and holding voltage condition at 1.6 V (more than 100 h). Besides, these textile-based capacitors also showed slow self-discharge.This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology (project POCI-01-0145-FEDER-007136). A. J. Paleo acknowledges the European COST Action CA15107- Multi-Functional Nano-Carbon Composite Materials Network (MultiComp) that conceded a Short Term Scientific Mission (STSM) at CNR-ITAE of Messina.info:eu-repo/semantics/publishedVersio