A theory of many-body wave scattering is developed under the assumption a << d << λ, where a is the characteristic size of the small body, d is the distance between neighboring bodies and λ is the wave-length in the medium in which the bodies are embedded. The multiple scattering is essential under these assumptions. The author’s theory is used for creating materials with a desired refraction coefficient. This theory can be used in practice. A recipe for creating materials with a desired refraction coefficient is formulated. Materials with a desired radiation pattern, for example, wave-focusing materials, can be created.
The PPP scholarly work has effectively explored the material values attached to PPPs such as efficiency of services, value for money and productivity, but little attention has been paid to procedural public values. This paper aims to address this gap by exploring how Enfidha Airport in Tunisia failed to achieve both financial and procedural values that were expected from delivering the airport via the PPP route, and what coping strategies the public and private sectors deployed to ameliorate any resultant value conflicts. Based on the analysis of Enfidha Airport, it is argued that PPP projects are likely to fail to deliver financial and procedural values when the broader institutional context is not supportive of PPP arrangements, and when political and security risks are not adequately counted for during the bidding process.
The conversion of the energy supply to renewable sources (wind, photovoltaics) will increase the volatility in electricity generation in the future. In order to ensure a balanced power balance in the power grid, storage is required - not only for a short time, but also seasonally. The bidirectional coupling of existing energy infrastructure with the power grid can help here by using the electricity in electrolysis systems to produce hydrogen. The hydrogen can be mixed with natural gas in the existing infrastructure (gas storage, pipelines) to a limited extent or converted directly to methane in a gas-catalytic reaction, methanation, with carbon dioxide and/or carbon monoxide. By using the natural gas infrastructure, the electricity grids are relieved and renewable energies can also be stored over long periods of time. Another advantage of this technology, known as “Power-to-Gas”, is that the methane produced in this way represents a sink for CO2 emissions, as it replaces fossil sources and CO2 is thus fed into a closed cycle.
Research in the field of Power-to-Gas technology is currently addressing technological advances both in the field of electrolysis and for the subsequent methanation, in particular to reduce investment costs. In the field of methanation, load-flexible processes are to be developed that are adapted to the fluctuating supply of hydrogen. The profitability of the Power-to-Gas process chain can be increased through synergistic integration into existing industrial processes. For example, an integrated smelting works offers a promising infrastructural environment, since, on the one hand, process gases containing carbon are produced in large quantities and, on the other hand, the oxygen as a by-product from the water electrolysis can be used directly. Such concepts suggest an economic application of Power-to-Gas technology in the near future.
A review of the CARG Project of the Campania Region (marine counterpart) up to water depths of 200 m is herein proposed referring to the Gulf of Naples (southern Tyrrhenian Sea) aimed at focusing on the main scientific results obtained in the frame of this important project of marine geological cartography. The Gulf of Naples includes several geological sheets, namely n. 464 “Island of Ischia” both at the 1:25,000 and 1:10,000 scale, n. 465 “Island of Procida” at the 1:50,000 scale, n. 466–485 “Sorrento–Termini” at the 1:50,000 scale, n. 446–447 Naples at the 1:50,000 scale, and n. 484 “Island of Capri” at the 1:25,000 scale. The detailed revision of both the marine geological and geophysical data and of the literature data has allowed us to outline new perspectives in marine geology and cartography of Campania Region, including monitoring of coastal zone and individuation of coastal and volcano-tectonic and marine hazards.
The objective of the work was to evaluate and compare the physicochemical characteristics of an experimental cabotiá hybrid with the commercial hybrid Tetsukabuto. The genotypes were divided according to mass (kg), and were evaluated for quality. The color parameters evaluated showed no significant difference, although visually the hybrid was different from the commercial variety. It was possible to conclude that the size of the fruits does not influence the concentration of the compounds, and also, an inferiority of HC05 was observed with respect to the relevant quality characteristics in pumpkins, such as soluble solids content, carotenoids and vitamin C.
Horticulture is a widespread activity in family farming in the Transamazonian region—Pará, with emphasis on production aimed at the family’s own consumption. The lettuce cultivar Vanda (Lactuca sativa L.) represents a significant part of this production, which prioritizes the use of internal labor. The main objective of this work was to evaluate the development of lettuce CV Vanda grown in beds using organic compost and chemical fertilization (NPK). The criteria considered to evaluate this performance were: Root system development, plant height and total fresh mass production. The best averages in relation to root development occurred in the plots cultivated with organic compost in the proportion of 5 kg/m2, due to its characteristics as a fertilizer and soil conditioner. The cultivation with the use of NPK provided the best averages in relation to the production of total fresh mass and plant height, results that were mainly attributed to the extra supply of nitrogen in the covering fertilization, which consisted in the addition of 10 g urea per square meter via soil. Statistical analysis showed no statistically significant difference regarding plant height for both treatments. And in relation to root development, the difference was statistically significant.
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