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Artículos en revistas This paper describes the long term transmission expansion planning model CHOPIN. In CHOPIN, the network expansion is formulated as the static optimization problem of minimizing the global annual cost of electricity production, which is obtained as the sum of the annualized network investment cost, the operation cost and the reliability cost. The solution method takes advantage of the natural decomposition between the investment and operation submodels. The investment submodel is solved by a new heuristic procedure that in practice has invariably yielded the optimal plan. At the operation level CHOPIN optimizes over a multiplicity of scenarios which are characterized by the demand, the hydraulicity and the availability of components. The network is represented by any one out of four options: DC load flow (DCLF), transportation model and two hybrid models. Any of these models may consider the ohmic losses. The model is very efficient computationally; this fact was verified on rest examples, as well as on the actual transmission expansion planning of the Spanish system. info:eu-repo/semantics/publishedVersion

Artículos en revistas This paper presents a continuation and optimization based algorithm to detect power flow unsolvability. In addition, the algorithm obtains the power flow solution, if it exists, no matter how ill-conditioned the power system is. The proposed algorithm is based on the parameterization of the distance from the starting point to the real power flow to be solved, using a convergence margin. The performance of the algorithm is illustrated considering an highly loaded scenario of the operation of the Spanish power system. info:eu-repo/semantics/publishedVersion

Capítulos en libros This paper presents a method for calculation of stationary Power Quality Disturbances-PQD based on measurements, distribution system modeling and Monte Carlo techniques. A method to simulate PQD with specific random behavior based on Perfect Sampling is proposed. Three non-sinusoidal conditions power quantities are employed to illustrate the proposed methodology, and a proposal for statistical interpretation of simulated results is presented as well. info:eu-repo/semantics/publishedVersion

Abstract The Mediterranean region is one of the most vulnerable regions to climate change. The majority of climate models forecast a rise in temperatures and less rainfall, which have been observed in recent decades. These changes will affect several vegetation properties, especially phenological dynamics and traits, by increasing drought intensity and recurrence. In this climate change context, the present study aims to assess the evolution of vegetation state and its relation with the climate dynamics in the Mediterranean forest region of northeast Tunisia using Land Surface Phenology (LSP) metrics and the vegetation index (NDVI) analysis from 2000 to 2017. To conduct this work, we used precipitation and temperature data from the two closest weather stations and 16-day NDVI composite images from the MODIS satellite source, with 250-m spatial resolution. Three phenological metrics— start of season (SOS), end of season (EOS), and length of season (LOS) — were obtained and compared for different vegetation types. The LSP variation in response to climatic metrics was also analyzed. The results showed that the LSP in our study area changed significantly during the 2000–2017 period, which includes an average 7.8 days delay in the SOS, an average advance in the EOS by 5 days, and LOS shortened by an average 12.8 days. Autumn (Pr_9) and spring (Pr_3 and P3_4) precipitations, as well as maximum temperature (Tx9+10), represent the best climate parameters to explain the changes in LSP. Both the NDVI and SPEI showed a significant high correlation (p

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The use of plastic materials in agriculture causes the serious drawback of huge quantities of waste. The introduction of biodegradable materials, which can be disposed directly into the soil, can be one possible solution to this problem. Biodegradable materials are actually innovative materials; therefore, their physical properties must be evaluated in relation to their functionality during the use in field. In the present research results of experimental tests carried out on biodegradable films used in strawberries protected cultivation are presented. The decay of some relevant physical parameters of biodegradable films during the cultivation period was monitored by laboratory tests (SEM analysis, mechanical tensile tests and infrared reflectance spectroscopy). Infrared spectroscopy clearly indicated that the mechanical degradation starts from the starch component of the material. Tensile tests showed that the value of elongation at break of biodegradable materials decreased in some cases by 300% after 10 days of field application

AbstractBackgroundN2O is a powerful greenhouse gas emitted in nitric acid plants, and emission control technologies are required.ResultsA 0.25%Rh/50%Ce0.9Pr0.1O2/γ‐Al2O3 catalyst has been prepared and tested for N2O decomposition in a real nitric acid plant gas stream. The catalyst is active enough to achieve 100% N2O removal, maintaining a constant catalytic activity after 40 h operation without deactivating. Characterization of the fresh and used catalyst, using different techniques, revealed no changes during the N2O decomposition experiments: (i) XRD and Raman spectroscopy show the fluorite structure of the Ce–Pr mixed oxide before and after the catalytic tests, (ii) the crystal size of the Ce–Pr mixed oxide particles and the BET surface area of the catalyst is maintained, evidencing no sintering of ceria particles, (iii) H2‐TPR indicates that the reducibility of the catalyst is similar before and after the catalytic tests, revealing chemical stability, and (iv) TEM and XPS analysis indicated the high stability of the rhodium particle size and oxidation state.ConclusionAn active and stable catalyst with formulation 0.25%Rh/50%Ce0.9Pr0.1O2/γ‐Al2O3 has been prepared and successfully tested for N2O decomposition in a real nitric acid plant gas stream. © 2013 Society of Chemical Industry

The launch traffic to Low Earth Orbit (LEO) is undergoing significant changes: instead of launching few, complex, large and expensive spacecraft, the trend is now towards the use of multitudes of small, less complex and lower-cost satellites. Large constellations, encompassing thousands of satellites in restricted regions of space, are emerging as important space assets. The intensifying commercial use of LEO and international debate regarding the stability of the space environment is a growing discussion among policy makers. Utilizing the SDM 5.0 evolutionary model developed by the Italian National Council of Research (CNR), the first step of this analysis is to estimate the growth of the space objects in LEO in the next decades. The analysis considers the space objects >10 cm, including active and defunct satellites, spent rockets bodies and fragments, along with varying future traffic, mitigation and remediation scenarios. Subsequently, the analysis focuses on the probability of collision with active satellites and on related mitigation and remediation scenarios. Based on this, the study employs a qualitative and preliminary approach to assess satellite operators' economic convenience of adopting measures that can mitigate the risk of collision by comparing their cost to the damage costs that may occur in case of collision. Finally, the study dedicate its concluding considerations to discuss if a free market setting can stimulate the formation of effective solutions to space debris challenges (namely, if it provides operators with the economic incentive to adopt or develop mitigation measures) or if public institutions' intervention is needed to finance mitigation strategies and, in particular, complex technologies development and adoption.