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21.
Experimental adsorption isotherm of two basic dyes: Basic Blue 3 and Basic Red 24 from aqueous solution onto modified nylon 6,6 were analyzed by using a double layer adsorption model with two energy levels. Such model is based on statistical physics treatment. The parameters involved in the analytical expression of this model such as the fraction or the number of adsorbed dye molecule(s) per site, n, the receptor sites density, NM, and the energetic parameters, c1 and c2, were determined by fitting the experimental adsorption isotherms at four temperatures between 293 and 353 K with different degrees of grafting between 20 and 80%. The evolution of these parameters versus temperature and the grafting percent allows us to interpret and better understand this adsorption process at molecular level. Two different behaviors of the two dye molecules were highlighted according to their localized and non localized charges. The configurational entropy at various temperatures has also been studied. This parameter allowed to deduce some results related to the evolution of the disorder at the adsorption surface. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   
22.
Since the early 1990s, there has been a growing interest in four‐dimensional computer aided design (4D CAD) for construction project planning. Commercial 4D CAD applications are becoming more accessible and the use of this technology allows the construction planner to produce more rigorous schedules. A review of the technical competencies of these packages highlights that most of the commercially available packages concentrate on the use of 4D CAD simulations for aesthetic visualization purposes. Very few packages offer the ability to carry out analytical tasks on the developed simulation and this is often left to the interpretation of the user. A thorough appraisal of emerging research developments in 4D planning highlights that this technology is employed for various applications; however, the amount of detail required in a 4D simulation is still ambiguous. A model is proposed to determine the attributes required for use with each of the various applications of 4D CAD simulations. Finally, various lines of future research are highlighted, including the need for improved use of data exchange standards and the automation of linking the construction tasks to the 3D CAD model.  相似文献   
23.
Higher‐resolution schemes are presented for convective flow approximation on highly distorted unstructured grids. The schemes are coupled with continuous full‐tensor Darcy‐flux approximations. A sequence of non‐uniform and distorted grid formulations are developed and compared for a range of unstructured meshes with variable grid spacing. The higher‐order schemes are constructed using non‐uniform grid slope limiters such that they are stable with a local maximum principle, ensuring that solutions are free of spurious oscillations. Benefits of the resulting schemes are demonstrated for classical test problems in reservoir simulation including cases with full‐tensor permeability fields. The test cases involve a range of unstructured grids with variations in grid spacing, orientation and permeability that lead to flow fields that are poorly resolved by standard simulation methods. The higher‐order formulations are shown to effectively reduce numerical diffusion, leading to improved resolution of concentration and saturation fronts. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
24.
The objective of this study was to investigate the chemical composition of the essential oils from citrus species, as well as their antioxidant and antimicrobial activities. By gas chromatography-mass spectrometry, we identified thirty-seven metabolites and a range of unique compounds, contributing to the discrimination of the species. Different biological potentialities were detected depending on the species supported the significant effect of the genetic factor. C. aurantium and C. limon exhibited the highest antioxidant activities which make them a potential source of natural preservative. C. limon exhibited the highest antibacterial activities and C. reticulata the highest antifungal activities. Essential oils extracted from these agro-wastes could serve as natural food preservatives to prevent food pathogens and then extending the shelf life. A set of potential metabolites could be implicated in the observed biological activity, underlying that the antimicrobial activity is a complex trait.  相似文献   
25.
There is an opportunity for real-estate services sector to deliver more accurate, faster and quality building surveys and information models. This paper reports on a study, designed to establish automated procedures for the development of a digital model to assist in faster and better services and delivery of real-estate services by integrating 3D laser scanning and BIM technology. It proposes an intuitive and interactive building model that is easy to query and navigate, and thus support property developers, buyers and sellers in the property sales sector. An outline of the new approach is provided to illustrate the benefits of the proposed method to the real-estate services sector. The key arguments in the paper are consolidated by the results of a qualitative study amongst real-estate professionals, which sought to determine the added value of BIM-3D laser scanning in comparison to conventional building surveying and Computer Aided Design (CAD) methods.  相似文献   
26.
The aim of this work was to simulate in two-dimensions the spatio-temporal evolution of the moisture content, the temperature, and the mechanical stress within a highly deformable and water saturated product during convective drying. The material under study was an elongated potato sample with a square section placed in hot air flow. A comprehensive hydro-thermal model had been merged with a mechanical model, assuming a viscoelastic material, a plane deformation, and an isotropic linear hydric-shrinkage of the sample. This model was validated on the basis of the average water content and core temperature curves for drying trials under different operating conditions. The material viscoelastic properties were measured by means of stress relaxation tests at different water contents. The viscoelastic behavior was described by a generalized Maxwell model whose parameters were correlated to water content. The simulations of the spatio-temporal distributions of mechanical stress were performed and interpreted in terms of product potential damage. The sample shape was also predicted all aver the drying process with reasonable accuracy.  相似文献   
27.
With reference to a preceding paper, this paper allows, in a first step, to determine, at low and high frequencies, approached expressions of the induced common mode voltages at the extremities of a shielded line influenced by a punctual current injection along the shield. These expressions are established for the case of a helicoidal screen with four different schemes of earth connections at the extremities. In a second step, the correction function, i.e. the ratio between the exact and approached solution, and the limit of validity of this latter at high frequencies are addressed.  相似文献   
28.
Use of Power Lines Communication for purpose such as Internet access or in-home applications seems to be a very attractive way, however, the problem of conducted and radiated electromagnetic emissions due to these new systems is quite set. The risk of disturbing the Radio communications is, at all, critical in the so-called Short Waves band, from 1 MHz to 30 MHz, allowed to PLC. This paper is aimed in analysing the phenomena that rise to these radiated electromagnetic emissions. We focus especially the analysis to the characterisation of magnetic field by means of simple physical concepts. The experimental and theoretical investigations involve usual power lines owning different dimension and complexity. A large part of this paper is devoted to physical interpretations of the measurement results, underlining the correlation between the magnetic field emission and the common and differential modes currents driven through the line, as well as the connection with the geometrical parameters of the line and with the connected loads. Finally, we present an approach that allows the assessment of the power deliverable by PLC. devices in accordance with the requirements of the harmonised standard EN55022 dealing with conducted emission on the power network.  相似文献   
29.
Water Resources Management - Rainfall, as one of the key components of hydrological cycle, plays an undeniable role for accurate modelling of other hydrological components. Therefore, a precise...  相似文献   
30.
OBJECTIVE: To review recent experience of gastroschisis at the Royal Children's Hospital, Melbourne. METHODOLOGY: Retrospective review of admissions over a 13 year period, June 1980-June 1993 inclusive, including an analysis of those factors influencing mortality, morbidity and complications. RESULTS: There were 49 infants, of whom two died (4%), both having an associated bowel atresia. Mode of delivery, age at operative repair, birthweight centile and silo repair had no significant effect on the duration of total parenteral nutrition (TPN) or hospital stay. The presence of short gut and/or gut resection and localized bowel narrowing or bowel atresia resulted in a significant increase in the duration of TPN and hospital stay. The presence of a central venous line was a highly significant risk factor for the development of systemic sepsis. CONCLUSION: Currently gastroschisis has a good outlook with a low mortality. Infants with short gut/resection and bowel atresia have a long duration of TPN and hospitalization, with significant morbidity and complications.  相似文献   
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