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131.
J. Borges de Sousa G. Andrade Gonçalves 《Clean Technologies and Environmental Policy》2011,13(2):369-380
Unmanned vehicles have already proved invaluable in environmental field studies by providing levels of spatial–temporal sampling resolution which could have not been attained before. Recent trends show that the levels of spatial–temporal sampling resolutions attained with individual vehicles are feasible for wide areas through the operation of persistent vehicle networks. The possibility of persistent sampling over wide areas has the potential to revolutionize environmental field studies. The roles of unmanned vehicle systems in future environmental field studies are discussed in the light of the recent technological developments and trends, along with the major challenges associated to this vision. The discussion is illustrated with examples of developments from the Underwater Systems and Technologies Laboratory from Porto University, Portugal. 相似文献
132.
Optimization of Multireservoir Systems by Genetic Algorithm 总被引:1,自引:1,他引:0
Application of optimization techniques for determining the optimal operating policy of reservoirs is a major issue in water resources planning and management. As an optimization Genetic Algorithm, ruled by evolution techniques, have become popular in diversified fields of science. The main aim of this study is to explore the efficiency and effectiveness of genetic algorithm in optimization of multi-reservoirs. A computer code has been constructed for this purpose and verified by means of a reference problem with a known global optimum. Three reservoirs in the Colorado River Storage Project were optimized for maximization of energy production. Besides, a real-time approach utilizing a blend of online and a posteriori data was proposed. The results obtained were compared to the real operational data and genetic algorithm was found to be effective and can be utilized as an alternative technique to other traditional optimization techniques. 相似文献
133.
134.
This paper presents a numerical method to calculate the value function for a general discounted impulse control problem for piecewise deterministic Markov processes. Our approach is based on a quantization technique for the underlying Markov chain defined by the post jump location and inter-arrival time. Convergence results are obtained and more importantly we are able to give a convergence rate of the algorithm. The paper is illustrated by a numerical example. 相似文献
135.
Bernardo Mançano Fernandes 《Landscape Research》2019,44(7):892-907
ABSTRACTFrom the perspective of Brazilian agrarian geography, the conflicts generated by land tenure disputes have as protagonists the families of the Landless Workers’ Movement (Movimento dos Trabalhadores Rurais Sem Terra), traditional landowners, and agribusiness corporations. In this article, we present a reflection on land conflicts and the spatial and territorial production of latifundia, peasant smallholders, and large-scale agribusiness through studies of the landscapes of two municipalities in the state of São Paulo. Among the various tools for analysing territorial disputes, Google Earth can be used for local, regional, and international comparative studies of how landscapes have been transformed. Informed by traditional research, the article analyses a diversity of photographs, from satellite to field shots, as evidence of landscapes that express conflicting social relations in disputes over different models of social and territorial development. 相似文献
136.
Simoens François Meilhan Jérôme Nicolas Jean-Alain 《Journal of Infrared, Millimeter and Terahertz Waves》2015,36(10):961-985
Journal of Infrared, Millimeter, and Terahertz Waves - Sensitive and large-format terahertz focal plane arrays (FPAs) integrated in compact and hand-held cameras that deliver real-time terahertz... 相似文献
137.
Kutlu B. Kavaklıoğlu Süheyla Aydin Miray Çelikbilek A. Erçin Ersundu 《International Journal of Applied Glass Science》2015,6(4):406-418
Thermal behavior, structural properties, and phase equilibria of the (100−x)TeO2-xNa2O system were studied in the 5 ≤ x ≤ 50 mol% composition range. Investigation of glass formation behavior in the binary system was realized, and the glass formation range was determined as 7.5 ≤ x ≤ 40 mol%. Differential thermal analysis (DTA) and Fourier transform infrared (FTIR) spectroscopy techniques were used for thermal and structural characterization of the glasses. Influence of Na2O content on glass transition temperature (Tg), glass stability (∆T), density (ρ), molar volume (VM), oxygen molar volume (VO), and oxygen packing density (OPD) values of sodium tellurite glasses was evaluated considering the structural transformations in the glass network. For the phase equilibria studies, DTA, X-ray diffraction (XRD), and scanning electron microscopy/energy dispersive X-ray (SEM/EDS) techniques were utilized to characterize the heat-treated samples. According to the phase equilibria studies, three eutectic regions were detected in the 0 < x < 50 mol% composition range of the (100−x)TeO2-xNa2O system. A new invariant endothermic reaction was detected for the compositions between 40 ≤ x ≤ 45 mol%. Na2O.8TeO2 (11.11 mol% Na2O) compound that was claimed to exist in the binary system in the literature was found to be the metastable δ-TeO2 phase. 相似文献
138.
In this study, bentonite originating from Turkey (Eski?ehir province) and activated carbon obtained from grapeseed were used as adsorbents for the removal of lead (Pb2+) and copper (Cu2+) ions from aqueous solutions. Experiments were performed in single- and binary-ion systems at constant temperature of 298 K and pH value of 5. In order to describe the adsorption mechanism Langmuir, Freundlich and Temkin isotherms were used. The total adsorption capacity values of adsorbents were compared. It was observed that the total adsorption capacity values were changed depending on the type of adsorbent used, type of metal ion and interaction between metal ions. 相似文献
139.
Platinum electrocatalysts were prepared using PtCl4 as a starting material and 1-decylamine, N,N-dimethyldecylamine, 1-dodecylamine, N,N-dimethyldodecylamine, 1-hexadecylamine, and 1-octadecylamine as surfactants. These surfactants were used for the first time in this synthesis to determine whether the primary and/or tertiary structure and/or chain length of the surfactants, affects the size and/or activity of the catalysts in C1–C3 alcohol electro-oxidation reactions. Electrochemical measurements (cyclic voltammetry and chronoamperometry) indicated that the highest electrocatalytic performance was observed for the Pt nanocatalysts that were stabilized by N,N-dimethyldecylamine, and this has a tertiary amine structure with a short chain length (R = C10H21). The high performance may be due to the high electrochemical surface area, Pt(0)/Pt(IV) ratio, %Pt utility, and roughness factor (R f). X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy, and transmission electron microscopy were used to determine the parameters that affect the catalytic activities. 相似文献
140.
Negar Naghavi Solange Temgoua Thibaud Hildebrandt Jean Franois Guillemoles Daniel Lincot 《Progress in Photovoltaics: Research and Applications》2015,23(12):1820-1827
The purpose of the present paper is to focus on the impact of oxygen gas partial pressure during the sputtering of i‐ZnO and ZnMgO on the transient behavior of Cu(In,Ga)Se2 (CIGSe) based solar cells parameters when a CBD‐Zn(S,O) buffer layer is used. Based on electrical characterization of cells, it is observed that the effect of light soaking is different on J–V characteristics depending on whether oxygen is or is not present during the first deposition time of the i‐ZnO or ZnMgO layers. In fact, when cells are prepared with standard i‐ZnO, the efficiencies are very low and a pronounced transient behavior is observed. However, when the first 10 nm of i‐ZnO or ZnMgO is formed by sputtered layer without adding oxygen during the process, depending on the thickness of the buffer layer, the transient effects strongly decreases. It is then possible to get stable cells reaching efficiencies quite similar to the CdS reference cells, especially with ZnMgO, without any post‐treatments. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献