The effect of carbon black concentration on the dynamic mechanical properties of bromobutyl rubber vulcanizates has been studied over a wide range of temperature (– 150 to + 250 °C), frequency (3.5 to 110 Hz) and dynamic strain amplitude (0.07 to 5%). The influence of carbon black concentration on the glass-rubber transition has also been investigated with respect to the isochronal variation in dynamic properties. The influence of carbon black concentration consists mainly of the change in the levels of the moduli values in the glassy and rubbery state. In the glassy region; the increase in stiffness with carbon black loading may be fully explained by the hydrodynamic effect of the carbon black particles embedded in the polymer continuum. With increased carbon black concentration the glass-rubber transition temperature (tan peak temperature) does not show a shift in its location but peak shoulder broadening and decrease in peak height are observed. At a particular temperature, the effect of carbon black concentration on dynamic properties of bromobutyl rubber is dependent on the combined effects of applied strain amplitude and frequency. With increase in filler concentration the thermal stability of the vulcanizate increases. 相似文献
Multimedia Tools and Applications - Indoor air pollutants e.g., Carbon dioxide (CO2), Particulate Matter(PM)2.5, PM10, Total Volatile Organic Compounds (TVOC), etc. have a serious impact on human... 相似文献
The present article proposes a geometry-based fuzzy relational technique for capturing gradual change in human emotion over time available from relevant face image sequences. As associated features, we make use of fuzzy membership arising out of five triangle signatures such as - (i) Fuzzy Isosceles Triangle Signature (FIS), (ii) Fuzzy Right Triangle Signature (FRS), (iii) Fuzzy Right Isosceles Triangle Signature (FIRS), (iv) Fuzzy Equilateral Triangle Signature (FES), and (v) Other Fuzzy Triangles Signature (OFS) to achieve the task of appropriate classification of facial transition from neutrality to one among the six expressions viz. anger (AN), disgust (DI), fear (FE), happiness (HA), sadness (SA) and surprise (SU). The effectiveness of the Multilayer Perceptron (MLP) classifier is tested and validated through 10 fold cross-validation method on three benchmark image sequence datasets namely Extended Cohn-Kanade (CK+), M&M Initiative (MMI), and Multimedia Understanding Group (MUG). Experimental outcomes are found to have achieved accuracy to the tune of 98.47%, 93.56%, and 99.25% on CK+, MMI, and MUG respectively vindicating the effectiveness by exhibiting the superiority of our proposed technique in comparison to other state-of-the-art methods in this regard.
The immobilization of strontium over titania was carried out by the method of coprecipitation. From a preliminary study, an appreciable uptake (52.8%) of90Sr was observed over preformed titania material. A weighable amount of strontium was coprecipitated with Ti(IV) hydroxide and a maximum of 34 wt% Sr was found to be adsorbed. The leachability of the mixed materials prepared by the addition of 250 and 400 mg Sr2+, calcined at 1000 °C, by soxhlet apparatus refluxing at 97 °C and repeated seven times at intervals of 24 h, was found to be of the order of 10–9 and 10–5 g cm–2 d–1, respectively. X-ray powder diffraction analysis revealed that strontium was immobilized in the crystalline matrix of rutile, which suffered some structural changes with the formation of new phases, SrTiO3+Sr2TiO4 and SrTiO3, respectively. 相似文献
Learning Management System (LMS) is an application software that is used in automation, delivery, administration, tracking, and reporting of courses and programs in educational sector. The LMS which exploits machine learning (ML) has the ability of accessing user data and exploit it for improving the learning experience. The recently developed artificial intelligence (AI) and ML models helps to accomplish effective performance monitoring for LMS. Among the different processes involved in ML based LMS, feature selection and classification processes find beneficial. In this motivation, this study introduces Glowworm-based Feature Selection with Machine Learning Enabled Performance Monitoring (GSO-MFWELM) technique for LMS. The key objective of the proposed GSO-MFWELM technique is to effectually monitor the performance in LMS. The proposed GSO-MFWELM technique involves GSO-based feature selection technique to select the optimal features. Besides, Weighted Extreme Learning Machine (WELM) model is applied for classification process whereas the parameters involved in WELM model are optimally fine-tuned with the help of Mayfly Optimization (MFO) algorithm. The design of GSO and MFO techniques result in reduced computation complexity and improved classification performance. The presented GSO-MFWELM technique was validated for its performance against benchmark dataset and the results were inspected under several aspects. The simulation results established the supremacy of GSO-MFWELM technique over recent approaches with the maximum classification accuracy of 0.9589. 相似文献
This paper presents various applications of evolutionary computing approach for architectural space planning problem. As such
the problem of architectural space planning is NP-complete. Finding an optimal solution within a reasonable amount of time
for these problems is impossible. However for architectural space planning problem we may not be even looking for an optimal
but some feasible solution based on varied parameters. Many different computing approaches for space planning like procedural
algorithms, heuristic search based methods, genetic algorithms, fuzzy logic, and artificial neural networks etc. have been
developed and are being employed. In recent years evolutionary computation approaches have been applied to a wide variety
of applications as it has the advantage of giving reasonably acceptable solution in a reasonable amount of time. There are
also hybrid systems such as neural network and fuzzy logic which incorporates the features of evolutionary computing paradigm.
The present paper aims to compare the various aspects and merits/demerits of each of these methods developed so far. Sixteen
papers have been reviewed and compared on various parameters such as input features, output produced, set of constraints,
scope of space coverage-single floor, multi-floor and urban spaces. Recent publications emphasized on energy aspect as well.
The paper will help the better understanding of the Evolutionary computing perspective of solving architectural space planning
problem. The findings of this paper provide useful insight into current developments and are beneficial for those who look
for automating architectural space planning task within given design constraints. 相似文献
Keeping in mind the significance of hydrogels as an external stimuli sensitive super absorbing material, some transparent
covalent hydrogels of chitosan were prepared by crosslinking with varying amounts of formaldehyde solution used as crosslinking
agent. The characteristics of hydrogels were investigated by Fourier transform infrared (FT-IR) spectroscopy and swelling
experiments. The effect of crosslinking agent on water absorbency has been investigated. The hydrogels exhibited a relatively
higher swelling ratio in the range of 2066–3306% and equilibrium water content (EWC) in the range of 95-38–97 06% at pH 7
and 35°C temperature. The influence of external stimuli such as pH, temperature, and ionic strength of the swelling media
on equilibrium swelling properties has been observed. Hydrogels showed a typical pH and temperature responsive behaviour such
as low pH and high temperature has maximum swelling while high pH and low temperature show minimum swelling. An increase in
the ionic strength of swelling media caused a continuous decrease in the swelling of hydrogels at both acidic and basic pH. 相似文献
Fabrication and characterization of cast Al–2Mg alloy matrix composites reinforced with short steel fibers are dealt with in the present study. Three types of steel fiber were used: uncoated, copper coated and nickel coated. All the composites were prepared by the liquid metal route using vortex methods. When tested in tension, all composites exhibited improvement in strength due to high relative strength of steel fibers. The ductility was lowered except for the composite with copper coated fibers. Copper coated fiber reinforced composites gave the highest strength. Higher strength accompanied with appreciable ductility demonstrated by composites with copper coated fibers is attributed to the solid solution and fiber strengthening as well as good bonding at the interface. Composites reinforced with uncoated and Ni coated steel fibers did not exhibit strengthening to the level exhibited with copper coated fibers because brittle intermetallic phases are formed at the interface. These phases promote initiation and facilitate propagation of cracks. The observed fracture mechanism of composites was dimple formation, fiber breakage and pullout of fibers. Fracture surface of uncoated and Ni coated composites showed extensive pull out of fibers as well as fiber breakage confirming the above inference. In case of the copper coated composites dimple formation and coalescence was more extensive. EDX analysis showed a build up Cu, Ni, and Fe at the interface. 相似文献
Fracture assessment of pipe bends or elbows with postulated through wall crack is very essential for leak-before-break qualification of primary heat transport system piping of nuclear power plants. The methodology for fracture assessment of cracked elbows is still in developing stage. Any new development in theoretical aspect requires experimental validation. However, fracture test data on cracked elbows is not so abundant as straight pipes. The earlier experiments on cracked elbows were focused mainly on the determination of limit load. Other fracture parameters e.g. crack growth, crack initiation load or crack opening displacement were not reported in the open literature. Against this backdrop, a comprehensive experimental and theoretical program on component integrity has been initiated at Reactor Safety Division (RSD) of Bhabha Atomic Research Center (BARC), India. Under this program, a number of fracture tests have been carried out on elbows with through wall circumferential/axial cracks subjected to in-plane closing/opening bending moment. These test data are then thoroughly analysed numerically through non-linear finite element analyses, analytically through limit load comparison and also through comparison of crack initiation loads by finite element and R6 methods. These test data may be utilized in future for validation of new theoretical developments in the integrity assessment of through wall cracked elbows. 相似文献