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71.
72.
High-silica zeolites exchanged with transition metal ions (TMIs) are the subject of great interest for their unusual catalytic activity and selectivity. Structural information like coordination and accessibility of TMIs in zeolites are important factors for understanding their catalytic activity. Siting of TMIs in zeolites is typically obtained by spectroscopic (EXAFS, EPR, UV–vis and IR) and computational methods, as in the case of Co-ferrierite. However, some controversy exists in the literature concerning the model for incorporation of bare Co ions in ferrierite. We show here that the results of our synchrotron X-ray powder diffraction studies on Co- and Ni-exchanged ferrierite (Si/Al = 8.5) are in a good agreement with the model of Co siting based on an indirect spectroscopic approach and help to validate this model. By direct structural evidences, a possible explanation for the larger catalytic activity of Co sites in the main channels of ferrierite can be inferred. A combination of data from in situ XRD continuous monitoring of the Co ion migration during calcination and crystal-chemical considerations allows to device a strategy for the design of optimised co-cations containing Co-ferrierite catalysts.  相似文献   
73.
A distillation process for the production of hyperazeotropic ethanol from a dilute wine obtained from the fermentation of biomass has been studied. This process utilizes the coupling of a soft preconcentration stage and of a dehydration stage based on the salting-out effect produced by calcium chloride on the ethanol in an aqueous solution, with the disappearance of the azeotrope. The salt is employed in a close cycle, due to the presence of a regeneration stage, therefore no consumption of calcium chloride is noticed.

The distillation process utilizes one column consisting of two sections operating at different pressures in order to reach an efficient heat recovery.

In this paper, a simplified flow-sheet of the process and the principal operating conditions of the distillation column are illustrated. When compared with other processes, conventional or under development, this one is characterized by the promising reduction of the specific energy requirement.

The operating conditions chosen for the distillation with salt have been experimentally checked using a laboratory column running continuously with calcium chloride as salting-out agent. Moreover, the experiments confirmed the reliability of the mathematical model of the process. Further experiments are in progress with the aim of utilizing a mixture of salts which can be fed from the bottom of the dehydration section back to the fermentor, so that the salt regeneration stage can be reduced.  相似文献   

74.
Particle tracking in turbulent flows in complex domains requires accurate interpolation of the fluid velocity field. If grids are non-orthogonal and curvilinear, the most accurate available interpolation methods fail. We propose an accurate interpolation scheme based on Taylor series expansion of the local fluid velocity about the grid point nearest to the desired location. The scheme is best suited for curvilinear grids with non-orthogonal computational cells. We present the scheme with second-order accuracy, yet the order of accuracy of the method can be adapted to that of the Navier-Stokes solver.An application to particle dispersion in a turbulent wavy channel is presented, for which the scheme is tested against standard linear interpolation. Results show that significant discrepancies can arise in the particle displacement produced by the two schemes, particularly in the near-wall region which is often discretized with highly-distorted computational cells.  相似文献   
75.
Andreozzi R  Caprio V  Marotta R 《Water research》2002,36(11):2761-2768
The oxidation by H2O2 of 3,4-dihydroxybenzoic acid (3,4-DHB) in aqueous/goethite slurry at varying operating conditions (catalyst load, temperature, pH, substrate and hydrogen peroxide starting concentration) is investigated. At adopted catalyst loads the observed kinetic developments are consistent with a non-radicalic oxidation mechanism involving the interaction between hydrogen peroxide and 3,4-DHB acid both adsorbed on the active sites of the catalyst. The temperature dependence of rate parameters for the proposed model is also assessed.  相似文献   
76.
The physical gestures that operate music instruments are responsible for the qualities of the sound being produced in a performance. Gestural information is thereby crucial for a model of music performance, paired with a model of sound synthesis where this information is applied. The highly constrained nature of performers gestures makes this task suitable to be modeled via a constraint-based approach, coupled with a strategy aimed at maximizing the gestural comfort of performers. We illustrate the problem representation, the search strategy and a validation of the model against human performance.  相似文献   
77.
“场所精神”早在古罗马的传统信仰文化中就有所体现,古罗马人认为,每一种“独立的”本体(包括人和场所)都有自己的灵魂(genius)守护神灵,灵魂赋予本体以生命,如影随形,始终决定其外在的特征并反映其内在的本质。从“genius loci”这个词的组合上就可以看出,“genius”表示“What a thing is”,即“物之为何”,意味着理解力(intel igence)或精神技能的最高水平,而“loci”则为“地点”、“场所”之意,又“特定已知存在的地方”或“某事物的中心所在”,合起来就成为了一个标识场所本质的词条。而在某种意义上讲,场所也被认为是“一个人记忆的一种物体化和空间化”,或是“对一个地方的认同感和归属感”。著名的城市建筑学家诺贝格·舒尔茨(Christian Norberg-Schulz)在1979年明确提出“场所精神”的概念,认为场所是具有清晰特性的空间。如今,“场所精神”经常被用来指具有与众不同的氛围的场所或地点,或者是某种“精神性的场所(spirit of place)”,而不仅仅指某一位守护神。而在同种类型的建筑当中,其“场所精神”所表现出的气质往往是相同的,以至于每一类别的建筑都有其共通的“场所精神”,反映着相似的内在本质。这也在一定程度上诠释了为什么具备同种精神职能的建筑能够赋予人们同样的心灵体验。通常情况下,建筑艺术通过一些相类似的外在特征来表现这种近乎“同一”的内涵。例如,传统佛教建筑就常常通过“聚集”或“向心”的符号象征来重现佛陀讲经说法时的场景,并表达宇宙人生的真相。无论何时何地,只要不偏离符号象征的原型(prototype),这种“场所精神”就能够得到有效的延续。  相似文献   
78.
Applied Intelligence - The paper reports the results of an analysis of COVID-19 diffusion in Italy. The analysis was carried out with a new method based on the combined use of a 3 Way Decisions...  相似文献   
79.
Information system design and sizing constitute a complex, top-down process that tailors the technology architecture to application requirements. Practitioners usually tackle this top-down process by focusing on individual design aspects, such as data or specific applications, and by relying on their previous experiences to compare alternative architectural solutions. Acquisition costs are usually accounted for, but related operating and maintenance costs are often neglected or underestimated. The complexity of optimizing individual design problems leads researchers to avoid a global optimization perspective and, thus, the IS architecture is usually a result of the juxtaposition of multiple local optima.This paper takes an overall perspective on the cost minimization problem of information system design to achieve a better trade-off between cost and performance over the whole expected life of the technology architecture. A comprehensive design methodology is discussed as an integrating framework that accounts for all categories of costs, including design, implementation, maintenance, and operation, to achieve a globally cost-minimizing solution.  相似文献   
80.
Mussel-inspired chemistry was usefully exploited here with the aim of developing a high-efficiency, environmentally friendly material for water remediation. A micro-structured material based on polydopamine (PDA) was obtained by using liposomes as templating agents and was used for the first time as an adsorbent material for the removal of methylene blue (MB) dye from aqueous solutions. Phospholipid liposomes were made by extrusion and coated with PDA by self-polymerization of dopamine under simple and mild conditions. The obtained Liposome@PDA microspheres were characterized by DLS and Zeta potential analysis, TEM microscopy, and FTIR spectroscopy. The effects of pH, temperature, MB concentration, amount of Liposome@PDA, and contact time on the adsorption process were investigated. Results showed that the highest adsorption capacity was obtained in weakly alkaline conditions (pH = 8.0) and that it could reach up to 395.4 mg g−1 at 298 K. In addition, adsorption kinetics showed that the adsorption behavior fits a pseudo-second-order kinetic model well. The equilibrium adsorption data, instead, were well described by Langmuir isotherm. Thermodynamic analysis demonstrated that the adsorption process was endothermic and spontaneous (ΔG0 = −12.55 kJ mol−1, ΔH0 = 13.37 kJ mol−1) in the investigated experimental conditions. Finally, the applicability of Liposome@PDA microspheres to model wastewater and the excellent reusability after regeneration by removing MB were demonstrated.  相似文献   
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