Search results for "Note"
showing 10 items of 10709 documents
Closed-form solutions of the energy balance equation for drip laterals under the Darcy-Weisbach resistance formula
2018
Many studies have investigated easy methods to design drip laterals, as well as the best resistance equation to use, which is fundamental to accurately account for friction losses. This paper addresses both the features of lateral design relationships and the influence of the friction-loss equation on the design variables. First, simple closed-form solutions of the energy balance equation for both sloped and horizontal drip laterals are derived with the simplified Darcy-Weisbach resistance formula by assuming the Darcy friction factor as invariant versus the Reynolds number. Second, an error analysis is performed assuming the friction factor as constant in the design, which is compared to u…
Perspective on hydrogen energy carrier and its automotive applications
2014
The paper outlines the concept of energy carrier with a particular reference to hydrogen, in view of a more disseminated employment in the field of automotive applications. In particular hydrogen production is analyzed considering the actual state of the art and recent technologies applied in production from the primary sources (fossil fuels, renewable energies, and water electrolysis). Then the problem of hydrogen storage is considered both from technical and economical point of views. In particular, differences between physical and chemical storage are here considered with a particular glance to the most innovative technologies including carbon nanostructures. A review on the main problem…
Nano-structured materials in new and existing buildings: to improved performance and saving of energy
2009
Improving well-being in buildings, in relation to energy conservation, represents a great challenge. In southern Italy a basic problem is that of keeping buildings cool in the summer months. This problem affects not only newly-erected buildings, but also the large number of existing buildings, some of which are of historical importance. Nano-technology represents an excellent opportunity to harness the salvage of existing buildings to the living requirements of contemporary society. The use of nano-structured materials in newly-erected buildings will lead to improved performance and a considerable saving of energy. Above all, the use of nano-structured materials in existing buildings will p…
Synthesis and characterization of zinc carboxy–porphyrin complexes for dye sensitized solar cells
2018
Two zinc porphyrins, 2 and 8, have been synthesized. Porphyrin 8 displays better electronic communication between the dye and the TiO2 electrode. Photophysical measurements and electrochemistry experiments suggest that both porphyrins are very promising sensitizers for dye-sensitized solar cells (DSSCs). It was found that their molecular orbital energy levels favor electron injection and dye regeneration in DSSCs. Solar cells sensitized by 2 and 8 were fabricated, and it was found that they show power conversion efficiencies (PCEs) of 5.27% and 7.13%, respectively. Photovoltaic measurements (J–V curves) together with the incident photon-to-electron conversion efficiency spectra of the two c…
Near-infrared emissive bacteriochlorin-diketopyrrolopyrrole triads: Synthesis and photophysical properties
2019
International audience; The synthesis of unprecedented energy transfer triads containing a near-infrared (NIR) emissive bacteriochlorin subunit and two diketopyrrolopyrrole (DPP) moieties linked to each other via ethynyl or zero-carbon spacers is presented. Their optical and fluorescence properties were determined in CHCl3 and toluene. These photophysical measurements highlight the ability of DPP scaffold to act as an effective energy donor, which once excited in the range 450-550 nm resulting nearly exclusively NIR emission of hydroporphyrin (ETE > 96%). Since DPP dyes are valuable structurally tunable fluorophores that may be used in the construction of high-performance multicomponent pho…
Nanotechnologies for Active and Intelligent Food Packaging: Opportunities and Risks
2017
This chapter focuses on providing a comprehensive review on the current development of nanotechnology in the field of active and intelligent packaging for food. Systems devoted to intelligent food packaging require easy-to-read, cheap, robust, and safe systems that are able to provide on time information. Food and Drug Administration (FDA) considers that evaluations of safety, effectiveness, public health impact, or regulatory status of nanotechnology products should consider any unique properties and behaviors that the application of nanotechnology may impart. The lack of regulatory support providing standardized risk assessments of engineered nanomaterials (ENM) through integration of haz…
Automatic Recognition and Analysis of Scanned Non-crimp Fabrics for Calculation of their Fluid Flow Permeability
2007
Automatic recognition of scanned images of distorted bi-axial fiber bundle arrangements is considered in order to obtain the overall permeability of the formed fiber network. Scanned images are pre-processed with color normalization followed by usage of a threshold to find the pixels belonging to the bundles, the threads keeping the bundles together, and the distinct gaps formed between the bundles. Since the scanned images virtually have a perfect grayscale, the intensity can be treated as a corresponding signal of the image. Next the regular character of the fiber network is investigated using Fourier analysis on the fiber bundles as well as on the threads. The direction, position, and s…
Advanced models for smart multilayered plates based on Reissner Mixed Variational Theorem
2017
In the present work, families of equivalent singe layer and layer-wise models for the static and free vibrations analysis of magneto-electro-elastic multilayered plates are developed. The models are defined in the framework of a unified formulation, which offers a systematic approach for generating refined plate theories through suitable expansions of the through-the-thickness components of the relevant fields, considering the expansion order as a free parameter. The key features of the developed formulation are: a) the condensation of the electric and magnetic description into the mechanical representation, based on the quasi-static electric-magnetic approximation, which allows to reduce t…
Quality Assurance and Support Measures for Solar Cooling on System Level
2016
Abstract Within the IEA SHC Task 48 “Quality assurance and support measures for Solar Cooling” the analysis and evaluation of the systems has been one of the four main focuses. Here the activities are including the lab- and field-based characterization of the systems, the definition and application of performance figures, a guideline for a reliable monitoring procedure including methods for automated error detection and an updated overview on worldwide installed DEC systems including hints and good practice examples. They are furthermore leading to three different easy-to-use tools for solar cooling systems: The LCA tool considers environmental and energetic values for the evaluation, the P…
Smart Materials in Architecture
2016
The project activity presides over the choice of materials and technical capacity within two dimensions of action: the previous knowledge and the tension about the future. That allowed us to identify the succession of the “technological and material” paradigms that have come and gone, featuring the project with the arrival of new materials and production processes. The advent of composite smart materials has challenged all the materials overturning the features.