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161.
Panagiotis A. Drakatos Vladimir A. Vissikirsky Ioannis K. Kalavrouziotis Dimitris G. Skuras Sofia P. Drakatu 《The International journal of environmental studies》2013,70(6):813-833
Cultivation of forests and plant species by utilizing processed wastewater and sludge from the wastewater treatment plants is an effective method to reduce the release of harmful substances and provide favorable conditions for the development of agricultural sector under the shortage of water resources. For this purpose, the experiments have been carrying out to investigate the ability of species to absorb chemical elements under increased concentrations in wastewater, as well as other characteristics and features of species’ behavior in biological, chemical and physical aspects. The behavior is a result of complex cause‐effect dynamical interactions in ecological networks with unknown mathematical models of underlying functional relationships. There are two important features inherent in the investigation of cultivating species by processed wastewater: empirical modeling of species’ behavior and qualitative reasoning with imprecise information about this behavior. Proceeding from analysis of chains of interactions viewed as functional mappings between factors and investigated objects, the paper proposes a solution to the development of fuzzy modeling tools to support the investigation process. The proposed architecture includes the following components: a model that describes an ecological network under investigation; artificial neural network modules that model complex direct cause‐effect interactions; a fuzzy inference system that provides the investigator with qualitative reasoning about these interactions within a framework of the model; and control system that, under the requests from the investigator, controls the operation of the above components. 相似文献
162.
163.
Tania Maria Haas Costa Helena Sofia Hoffmann Edilson Valmir Benvenutti Valter Stefani Marcia Russman Gallas 《Optical Materials》2005,27(12):1819-1824
Sol–gel method and high-pressure technique were associated to produce silica compacts with low porosity and doped with rhodamine 6G (R6G). Acid catalyzed solutions of tetraethyl orthosilicate mixed with dye previously dissolved in ethanol were used for the synthesis of doped silica gel. The monolith obtained was comminuted and the powder was compacted between 3.0 and 7.7 GPa, at room temperature, using a toroidal-type high-pressure chamber. Excitation–emission fluorescence spectroscopy was used to investigate the optical properties of R6G embedded in the closed pores of the silica matrix. Measurements of surface areas and pore size distribution for the powders and compacts, using the N2 isotherms were performed, showing a great reduction in surface area and porosity, after compaction. The dye entrapped in the compacted silica maintains its optical properties similar to that in ethanolic solutions, meaning that the dye is dispersed in a molecular level. Additionally, these samples are optically transparent, hard and resistant to dye leaching and to chemical attacks, being a promising material to be used in optical devices. 相似文献
164.
Sofia Pegiadou-Koemtzopoulou Ioannis Eleftheriadis Aristidis Kehayoglou 《Journal of surfactants and detergents》1998,1(1):59-64
The complex-forming interaction between two direct dyes, CI Yellow 106 and CI Blue 78, and two nonionic surfactants, namely,
polyoxyethylene nonyl phenyl ether (NP-12) and polyoxyethylene stearylamine (R-11), in aqueous solutions was studied. The
estimation was made by measuring surface tension and critical micelle concentration (CMC) changes as a function of dye concentration.
A decrease of NP-12 surface tension at low concentration and an increase of R-11 surface tension in the presence of both dyes
were observed along with a significant decrease of NP-12 CMC values. A difference in the spectrophotometric absorbance of
dye solutions in the presence of both surfactants, indicating a change in the environment of the dye chromophore, was also
visible. These results confirm the formation of hydrophobic complexes of NP-12 and hydrophilic complexes of R-11 with both
dyes. 相似文献
165.
166.
An economically designed, integrated quality and maintenance model using an adaptive Shewhart chart 总被引:1,自引:0,他引:1
Sofia Panagiotidou Author Vitae Author Vitae 《Reliability Engineering & System Safety》2009,94(3):732-741
This paper proposes a model for the economic design of a variable-parameter (Vp) Shewhart control chart used to monitor the mean in a process, where, apart from quality shifts, failures may also occur. Quality shifts result in poorer quality outcome, higher operational cost and higher failure rate. Thus, removal of such quality shifts, besides improving the quality of the outcome and reducing the quality cost, is also a preventive maintenance (PM) action since it reduces the probability of a failure and improves the equipment reliability. The proposed model allows the determination of the scheme parameters that minimize the total expected quality and maintenance cost of the procedure. The monitoring mechanism of the process employs an adaptive Vp-Shewhart control chart. To evaluate the effectiveness of the proposed model, its optimal expected cost is compared against the optimum cost of a fixed-parameter (Fp) chart. 相似文献
167.
Sofia Luiza Brito Paulina Maria Maia‐Barbosa Ricardo Motta Pinto‐Coelho 《Lakes & Reservoirs: Research and Management》2011,16(4):253-264
The physical and chemical variables of the water, and the composition and structure of the zooplankton communities, in Três Marias and Furnas Reservoirs in Minas Gerais, Brazil, were compared to characterize these environments in relation to their trophic state. Higher values of electrical conductivity and chlorophyll‐a, total solids, suspended organic matter and total nitrogen concentrations were recorded in Três Marias Reservoir. Higher water transparency and nitrite and nitrate concentrations were observed in Furnas (P < 0.000). Higher zooplankton densities were always obtained in Três Marias Reservoir and, during the rainy period (P < 0.000), with mean values in the dry and rainy periods of 23 721 and 90 872 org m?3, respectively, in Três Marias Reservoir and 9022 and 40 434 org m?3, respectively, in Furnas Reservoir. Copepoda was the dominant group in both reservoirs, mainly the younger stages (nauplii and copepodids). Based on the absolute and relative values, the contribution of rotifers was higher in Três Marias Reservoir than in Furnas Reservoir. Although the Trophic State Index, based on water transparency and chlorophyll‐a and total phosphorus concentrations, indicated an oligotrophic state for both reservoirs, the higher densities of the zooplankton community in Três Marias Reservoir, as well as the predominance of cyclopoids and smaller‐sized species such as bosminids, characterized this environment as mesotrophic. Larger‐sized species such as calanoids, daphniids and sidids in Furnas Reservoir characterized the better water quality of this reservoir. 相似文献
168.
Silicon - The aim of this research work is to study the effects of non-uniform emitter sheet resistance on the performance of PERC solar cells. For this purpose, we used different simulation... 相似文献
169.
Álvaro J. Leite Mariana B. Oliveira Sofia G. Caridade João F. Mano 《Advanced functional materials》2017,27(28)
Platforms containing multiple arrays for high‐throughput screening are demanded in the development of biomaterial libraries. Here, an array platform for the combinatorial analysis of cellular interactions and 3D porous biomaterials is described. Using a novel method based on computer‐aided manufacturing, wettable regions are printed on superhydrophobic surfaces, generating isolated spots. This freestanding benchtop array is used as a tool to deposit naturally derived polymers, chitosan and hyaluronic acid, with bioactive glass nanoparticles (BGNPs) to obtain a scaffold matrix. The effect of fibronectin adsorption on the scaffolds is also tested. The biomimetic nanocomposite scaffolds are shown to be osteoconductive, non‐cytotoxic, promote cell adhesion, and regulate osteogenic commitment. The method proves to be suitable for screening of biomaterials in 3D cell cultures as it can recreate a multitude of combinations on a single platform and identify the optimal composition that drives to desired cell responses. The platforms are fully compatible with commercially routine cell culture labware and established characterization methods, allowing for a standard control and easy adaptability to the cell culture environment. This study shows the value of 3D structured array platforms to decode the combinatorial interactions at play in cell microenvironments. 相似文献
170.
Sofia Benyahya Bernard Boutevin Sylvain Caillol Vincent Lapinte Jean‐Pierre Habas 《Polymer International》2012,61(6):918-925
Polyhydroxyurethanes (PHUs) produced by the reaction between dicyclocarbonate and diamine groups are often presented as possible candidates to substitute for classical polyurethanes based on isocyanate precursors. In the literature, the synthesis of this class of polymers is often performed according to arbitrary conditions of time and temperature without any scientific justification. As such, the real potential of PHUs is probably not fully known. Numerous contradictions in previously published results seem to support this hypothesis. Our paper proposes two methodologies based on dynamic rheometry to determine optimized conditions for the synthesis of PHUs. The case of a PHU formed by the reaction between 1,10‐diaminodecane and a dicyclocarbonate bearing a central aromatic group is described more precisely. The first approach consists of conducting various rheological experiments (kinetics, thermomechanical analyses) in situ on the reaction mixture. The second one retains the same technique to qualify the viscoelastic properties of PHUs synthesized according to various conditions. In this latter case, all samples show thermomechanical behaviour of amorphous thermoplastic polymers. But discrepancies are observed with regard to the value of the glass transition temperature and the existence or not of a rubbery zone. Comparison of these data with size exclusion chromatography results shows that these differences are direct consequences of the polymer molecular weight that can be predicted using macromolecular theory. The properties of the PHUs obtained after optimization of the polymerization reaction were compared with literature data in order to complete the evaluation of the efficiency of the rheological methodology. Copyright © 2012 Society of Chemical Industry 相似文献