Search results for "GRI"
showing 10 items of 10209 documents
Adsorption equilibria of water vapor on cork.
2010
International audience; We report here for the first time a complete thermodynamic study of water vapor adsorption on crude cork powder and plate. Adsorption−desorption isotherms were accurately measured by thermogravimetry at 283, 298, and 313 K in a large range of relative pressure. Adsorption enthalpies were determined by calorimetry as a function of loading. Adsorption−desorption isotherms exhibit a hysteresis due to the swelling of the material. The influence of the presence of lenticels on the adsorption properties of cork is found to be negligible. A detailed analysis and interpretation of adsorption data allow proposal of an adsorption mechanism in two steps. (i) First, water adsorb…
Functionalized halloysite nanotubes: Efficient carrier systems for antifungine drugs
2018
Abstract Halloysite-cyclodextrin hybrid was employed as carrier for sustained release of clotrimazole for vaginal or buccal treatment of Candidiasis. The nanocarrier was obtained by functionalization of halloysite surface with cyclodextrin moieties by means of microwave irradiation, with the final goal to obtain a scaffold for the covalent linkage of cysteamine hydrochloride. The interaction between clotrimazole and the pristine components, namely cyclodextrin and halloysite, was thoroughly investigated by several techniques such as DSC, TGA, UV–vis spectroscopy and some adsorption studies were, also, carried out. The release of the antifungine molecule was finally investigated in a medium …
Life Cycle Energy Consumption and Carbon Dioxide Emissions of Agricultural Residue Feedstock for Bioenergy
2021
The depletion of fossil fuels and climate change concerns are drivers for the development and expansion of bioenergy. Promoting biomass is vital to move civilization toward a low-carbon economy. To meet European Union targets, it is required to increase the use of agricultural residues (including straw) for power generation. Using agricultural residues without accounting for their energy consumed and carbon dioxide emissions distorts the energy and environmental balance, and their analysis is the purpose of this study. In this paper, a life cycle analysis method is applied. The allocation of carbon dioxide emissions and energy inputs in the crop production by allocating between a product (g…
Effect of high hydrostatic pressure on extraction of B-phycoerythrin from Porphyridium cruentum: Use of confocal microscopy and image processing
2019
International audience; The aim of the study was to extract B-phycoerythrin from Porphyridium cruentum while preserving its structure. The high hydrostatic pressure treatments were chosen as extraction technology. Different methods have been used to observe the effects of the treatment: spectrophotometry and confocal laser scanning microscopy followed by image processing analysis. Image processing led to the generation of masks used for the identification of three clusters: intra, extra and intercellular. All methods showed that high hydrostatic pressure treatments between 50 and 500 MPa failed to extract B-phycoerythrin from Porphyridium cruentum cells. The fluorescence emission was negati…
Five-years-long effects of the Italian policies for photovoltaics on the energy demand coverage of grid-connected PV systems installed in urban conte…
2016
Abstract The paper examines the responsiveness of the electricity demand coverage in urban contexts to the changes in the Italian policies for PV systems. The morphological configuration of building roofs according to the number of covered flats, annual data of PV generation and electricity consumptions were considered in the transition from the feed-in tariff (FIT) mechanism to the tax credits scheme currently in force. With the aim of assessing the changes over time in three representative cities, the fluctuations both in the premiums for the produced electricity and the tax credits applied to the PV system costs were observed from July 2010 to February 2016. Furthermore, the main time-va…
Solar and Heat Pump Systems for Domestic Hot Water Production on a Small Island: The Case Study of Lampedusa
2020
The achievement of United Nations Sustainable Development Goals, related to energy and resource use, is a critical issue for small and insulated communities. In many minor islands, solar energy is not correctly exploited, and electrical heaters are connected to weak grids with very a high share of generation by fossil fuels. As a consequence, there is the necessity to assess the potential and the suitability of diffusion of alternative systems to avoid dependency on the electrical grid and reduce carbon emissions. This paper aims to evaluate the technical and economic performances of some alternative systems exploiting renewable energy for domestic hot water production. Four different syste…
Technical Rules for Connecting PV Systems to the Distribution Grid: A Critical Comparison of the Italian and Vietnamese Frameworks
2018
In the last two decades, starting from the Kyoto protocol, decarbonization has promoted worldwide the rise of distributed generation from renewable energy sources. Currently, Vietnam is still showing a strong dependence on fossil fuels but with a great interest in investing in renewable, especially in photovoltaic (PV) systems. In this paper, the current Vietnamese technical and administrative framework for the connection of PV systems to the power grid is presented and critically compared to the Italian one, in order to define the bases for future cooperation in distributed generation and renewable sectors.
District heating networks: enhancement of the efficiency
2019
International audience; During the decades the district heating's (DH) advantages (more cost-efficient heat generation and reduced air pollution) overcompensated the additional costs of transmission and distribution of the centrally produced thermal energy to consumers. Rapid increase in the efficiency of low-power heaters, development of separated low heat density areas in cities reduce the competitiveness of the large centralized DH systems in comparison with the distributed cluster-size networks and even local heating. Reduction of transmission costs, enhancement of the network efficiency by optimization of the design of the DH networks become a critical issue. The methodology for determ…
Linking the Kinetic Energy Fraction and Equivalent Length Method for Trickle Irrigation Design under Local Losses
2020
New methods using analytical relationships to design drip irrigation laterals and subunits have been introduced in recent years based on the assumption that minor losses can be neglected. This assumption could be relaxed by applying the equivalent method, which makes it possible to account for minor losses, such as those caused by emitter connections, through formulas based on the rationale that an equivalent length of the drip lateral produces the same losses. However, equivalent length formulas are empirical; thus, they do not necessarily cover the entire range of conditions in the real-world contexts in which the formulas will be applied, and their extrapolation could lead to erroneous r…
Experimental study and numerical simulation of inclined rectangular weirs
2018
Inclined rectangular weirs, also named pivot weirs, are used both to adjust the upstream water level and to increase the flow capacity compared with that of normal rectangular weirs. However, the experimental studies available in the literature present contradictory conclusions for the inclined weir discharge capacity. In this paper, new experimental runs and numerical simulations were performed to investigate the effect of the rectangular weir inclination angle on the stage-discharge formula. The experiments were carried out using inclination angles ranging from 30° to 90°. Buckingham's theorem of dimensional analysis was used to obtain an equation for the flow magnification ratio (the dis…