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151.
Shadpour Mallakpour Mohammad Zhiani Abdolvahid Barati Hussein Rostami 《International Journal of Hydrogen Energy》2013
The present investigation deals with the fabrication of new poly(vinyl alcohol)/titanium dioxide (PVA/TiO2) nanocomposites (NCs) with different titanium dioxide (TiO2) loading by using ultrasound irradiation. For the improvement of nanoparticles (NPs) dispersion and increasing possible interactions between NPs and PVA, the surface of TiO2 NPs was modified by γ-aminopropyltriethoxy silane. The as-prepared NCs were characterized by spectroscopic, thermogravimetric analysis and electron microscopy methods. The results demonstrate that NPs dispersed homogeneously within the PVA matrix on nanoscale, which could be assigned to the hydrogen and covalent bonds formed between PVA and NPs. The results indicated that heat stability of NCs was improved in the presence of modified TiO2 NPs. The mechanisms of surface modification and a possible mechanism of ultrasonic induced interaction between polymer and NPs have been analyzed. 相似文献
152.
With increases in storm frequency and intensity, municipalities are finding new ways of managing stormwater. Solutions require collaboration across planning disciplines and input from an informed public. This study compares a system of bioswales to existing curb and gutter infrastructure in a post-industrial streetscape of Hamilton, Ontario. Using the geodesign process, a section of Ottawa St. North was modelled to show how green infrastructure can ease the burden on aging, combined sewer systems. Qualitative data was gathered from residents of the neighbourhood through field notes, and quantitative geospatial data through GIS. Parametric modelling was used to generate a design, and scenarios created to show resulting impacts on stormwater run-off. The model was posted online as an interactive presentation, accessible to all stakeholders for review and comment. The results of the study demonstrate powerful new tools that can assist landscape architects in designing, collaborating and communicating stormwater strategies. 相似文献
153.
154.
Andrea Kleinsmith P. Ravindra De Silva Nadia Bianchi-Berthouze 《Interacting with computers》2006,18(6):1371-1389
Conveyance and recognition of human emotion and affective expression is influenced by many factors, including culture. Within the user modeling field, it has become increasingly necessary to understand the role affect can play in personalizing interactive interfaces using embodied animated agents. However, little research within the computer science field aims at understanding cultural differences within this vein. Therefore, we conducted a study to evaluate if differences exist in the way various cultures perceive emotion from body posture. We used static posture images of affectively expressive avatars to conduct recognition experiments with subjects from three cultures. After analyzing the subjects' judgments using multivariate analysis, we grounded the identified differences into a set of low-level posture features. We then used Mixture Discriminant Analysis (MDA) and an unsupervised expectation maximization (EM) model to build separate cultural models for affective posture recognition. Our results could prove useful to aide designers in creating more effective affective avatars. 相似文献
155.
Hussein A. Abbass 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2006,10(8):687-698
When an optimization problem encompasses multiple objectives, it is usually difficult to define a single optimal solution.
The decision maker plays an important role when choosing the final single decision. Pareto-based evolutionary multiobjective optimization (EMO) methods are very informative for the decision making process since they provide the decision maker with a set of efficient
solutions to choose from. Despite that the set of efficient solutions may not be the global efficient set, we show in this
paper that the set can still be informative when used in an interactive session with the decision maker. We use a combination
of EMO and single objective optimization methods to guide the decision maker in interactive sessions. 相似文献
156.
Kenneth Bryan Pádraig Cunningham Nadia Bolshakova 《IEEE transactions on information technology in biomedicine》2006,10(3):519-525
In a gene expression data matrix, a bicluster is a submatrix of genes and conditions that exhibits a high correlation of expression activity across both rows and columns. The problem of locating the most significant bicluster has been shown to be NP-complete. Heuristic approaches such as Cheng and Church's greedy node deletion algorithm have been previously employed. It is to be expected that stochastic search techniques such as evolutionary algorithms or simulated annealing might improve upon such greedy techniques. In this paper we show that an approach based on simulated annealing is well suited to this problem, and we present a comparative evaluation of simulated annealing and node deletion on a variety of datasets. We show that simulated annealing discovers more significant biclusters in many cases. Furthermore, we also test the ability of our technique to locate biologically verifiable biclusters within an annotated set of genes. 相似文献
157.
Samer Dessouky Eyad Masad Dallas Little Hussein Zbib 《Canadian Metallurgical Quarterly》2006,132(2):158-171
This paper presents the development of a methodology for microstructure analysis and modeling of hot mix asphalt (HMA). This methodology relies on using effective local material properties and strain gradient theory in the finite element analysis of HMA microstructure. The effective local properties are calculated using an analytical micromechanical model that captures the influence of percent of particles on the microscopic response of HMA. Strain gradient elasticity is used in order to account for the effect of particle size in the finite element analysis. The autocorrelation function and the moving window technique are used to determine the microstructure characteristic length scales that are used in strain gradient elasticity. A number of asphalt mixes with different aggregate types and size distributions are analyzed in this paper. 相似文献
158.
Elsayed Kandyel 《Journal of Superconductivity》1999,12(2):403-408
The single-phased series of Sr-bearing Hg-1212 superconducting cuprate,(Hg0.7Mo0.3)Sr2(Sr1–x
La
x
)Cu2O
z
has been prepared. X-ray diffraction showed that, the obtained samples belong to the 1212-structure with tetragonal space group P4/mmm, similar to that of (Hg, Mo)Sr2(Ca, Y)Cu2Oz, and stabilized in a wide compositional range of 0.25x0.75. Refinements of the structure are carried out in which the oxygen atoms at the (Hg, Mo) layer is shifted from high-symmetry position (0.5, 0.5, 0) to (x, x, 0). Magnetization and electrical resistivity measurements show that the as-prepared samples exhibit evidence for superconductivity and their superconducting properties were improved after O2 annealing with T
onset
c
as high as 92 K. 相似文献
159.
160.
A. A. Hussein 《Metallurgical and Materials Transactions A》1982,13(5):837-846
Dual-phase (α + martensite) microstructures were produced in binary Cu-Al alloys by quenching from the (α + β) phase field.
A wide range of martensite volume fraction VM was obtained, depending on alloy composition and quench temperatureT. Linear dependence onT of VM was established. Predefined values for VM can thus be achieved by adjustment ofT and alloy composition. Furthermore, the size, shape, and distribution of component phases can be varied in a predetermined
fashion by means of controlled cooling from the β range. The properties of α and martensite were tracedvia microhardness measurements. The microhardness of martensite increases with quench temperature in spite of the accompanying
decrease of its solute content. This is in accord with previous work and emphasizes the dominating role of martensite ordered
structure on strength. Such strength depends only on quench temperature irrespective of overall alloy composition or morphology.
The α microhardness is not affected by alloy composition or quench temperature. The martensitic phase can be hardened by means
of short time tempering due to order hardening or solute clustering effects. Depending on quench temperature, optimum use
of such temper hardening can be achieved. Moreover, cold working of dual-phase structures followed by annealing at temperatures
around 300 °C achieves substantial strengthening of both α and martensite. The strengthening of α is a consequence of anneal
hardening. Although such high strength levels are accompanied by reduction of the ductility (as measured by thickness reduction
achieved by cold rolling), the heat treatment schedule can be optimalized to achieve high strength while restoring ductility. 相似文献