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81.
Chandrashekhar P. Hiremath K. Senthilnathan Niranjan K. Naik Anirban Guha Asim Tewari 《Journal of Materials Engineering and Performance》2018,27(4):1685-1693
Representative volume element (RVE) has commonly been used to predict the stiffness of undamaged composite materials using finite element analysis (FEA). However, never has been an independently measured true microstructural damage quantity used in FEA to predict composite stiffness. Hence, in this work, measured fiber crack density in unidirectional fiber composite (generated using controlled fatigue loading) was used to predict reduction in stiffness using a RVE. It was found that the stiffness changes with change in depth of the volume element along the fiber direction and asymptotically reaches a constant value beyond a critical length called representative depth. It was argued that this representative depth should be more than the minimum of two characteristic length scales, twice of ineffective length and average length of broken fibers. Effective stiffness obtained from FEA of the optimum-sized RVE was in excellent agreement with the experimental results for given microstructural damage state. 相似文献
82.
Onur Celik Dolunay Sakar Fatih Cakar Ozlem Cankurtaran Ferdane Karaman 《应用聚合物科学杂志》2009,111(3):1328-1334
Crosslinked networks (NPPCS) and linear polymers (LPPCS) of poly (p‐chloro styrene) were synthesized by free‐radical polymerization of p‐chloro styrene. NPPCS networks were swollen in four different molecular weights of LPPCS solutions in toluene at three different concentrations. The equilibrium swelling results were evaluated by means of Flory‐Rehner theory to obtain network–linear polymer interaction parameter, χ′23 between NPPCS and LPPCS. It was concluded that the parameter χ′23 decreased with molecular weight but increased with concentration of LPPCS in outer solution. The solvent independent interaction parameter between NPPCS and PPCS was estimated as 0.7 by extrapolation of the values of χ′23 to zero value of the fraction ratio of solvent to linear polymer, ν1/ν3 inside the network. As well as, the binary interaction parameters, χ12 of NPPCS with benzene, ethyl benzene, n‐propyl benzene and isopropyl benzene were obtained by means of Flory‐Rehner theory at temperatures between 25 and 55°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
83.
Krishanu Sarkar Koushik Dhara Mahasweta Nandi Partha Roy Asim Bhaumik Pradyot Banerjee 《Advanced functional materials》2009,19(2):223-234
A highly ordered 2D‐hexagonal mesoporous silica material is functionalized with 3‐aminopropyltriethoxysilane. This organically modified mesoporous material is grafted with a dialdehyde fluorescent chromophore, 4‐methyl‐2,6‐diformyl phenol. Powder X‐ray diffraction, transmission electron microscopy, N2 sorption, Fourier transform infrared spectroscopy, and UV‐visible absorption and emission have been employed to characterize the material. This material shows excellent selective Zn2+ sensing, which is due to the fluorophore moiety present at its surface. Fluorescence measurements reveal that the emission intensity of the Zn2+‐bound mesoporous material increases significantly upon addition of various concentrations of Zn2+, while the introduction of other biologically relevant (Ca2+, Mg2+, Na+, and K+) and environmentally hazardous transition‐metal ions results in either unchanged or weakened intensity. The enhancement of fluorescence is attributed to the strong covalent binding of Zn2+, evident from the large binding constant value (0.87 × 104 M ?1). Thus, this functionalized mesoporous material grafted with the fluorescent chromophore could monitor or recognize Zn2+ from a mixture of ions that contains Zn2+ even in trace amounts and can be considered as a selective fluorescent probe. We have examined the application of this mesoporous zinc(II) sensor to cultured living cells (A375 human melanoma and human cervical cancer cell, HeLa) by fluorescence microscopy. 相似文献
84.
Service-oriented architecture (SOA) is defined as a paradigm for organizing and using distributed capabilities that might be under the control of different ownership domains. SOA is also known as a methodology for achieving application interoperability and reuse of IT assets in distributed computing environments characterized as transformable by the visibility, interaction, and effect dimensions. 相似文献
85.
A full band, three-dimensional, Monte Carlo simulator for deep sub-micron Si MOSFET like devices has been developed, with the goal to obtain optimal performance on a parallel system built from a cluster of commodity computers. A short-range carrier-carrier and carrier-ion model has been implemented within this framework, using Particle-Particle Particle-Mesh (P3M) algorithm. Test simulations include the 90 nm well-tempered MOSFET for which measurements are available. Simulation benchmarks have identified several factors limiting the overall performance of the code and suggestions for improvements in these areas are made. 相似文献
86.
Haiyan Jia Erik Mailand Jiangtao Zhou Zhangjun Huang Giovanni Dietler John M. Kolinski Xinling Wang Mahmut Selman Sakar 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(4)
Here, a soft robotic microgripper is presented that consists of a smart actuated microgel connected to a spatially photopatterned multifunctional base. When pressed onto a target object, the microgel component conforms to its shape, thus providing a simple and adaptive solution for versatile micromanipulation. Without the need for active visual or force feedback, objects of widely varying mechanical and surface properties are reliably gripped through a combination of geometrical interlocking mechanisms instantiated by reversible shape‐memory and thermal responsive swelling of the microgel. The gripper applies holding forces exceeding 400 µN, which is high enough to lift loads 1000 times heavier than the microgel. An untethered version of the gripper is developed by remotely controlling the position using magnetic actuation and the contractile state of the microgel using plasmonic absorption. Gentle yet stable robotic manipulation of biological samples under physiological conditions opens up possibilities for high‐throughput interrogation and minimally invasive interventions. 相似文献
87.
In this paper, we present a new design of hollow, out-of-plane polymeric microneedle with cylindrical side-open holes for
transdermal drug delivery (TDD) applications. A detailed literature review of existing designs and analysis work on microneedles
is first presented to provide a comprehensive reference for researchers working on design and development of micro-electromechanical
system (MEMS)-based microneedles and a source for those outside the field who wish to select the best available microneedle
design for a specific drug delivery or biomedical application. Then, the performance of the proposed new design of microneedles
is numerically characterized in terms of microneedle strength and flow rate at applied inlet pressures. All the previous designs
of hollow microneedles have side-open holes in the lumen section with no integrated reservoir on the same chip. We have proposed
a new design with side-open holes in the conical section to ensure drug delivery on skin insertion. Furthermore, the present
design has an integrated drug reservoir on the back side of the microneedles. Since MEMS-based, hollow, side-open polymeric
microneedles with integrated reservoir is a new research area, there is a notable lack of applicable mathematical models to
analytically predict structural and fluid flow under various boundary conditions. That is why, finite element (FE) and computational
fluid dynamic (CFD) analysis using ANSYS rather than analytical systems has been used to facilitate design optimization before
fabrication. The analysis has involved simulation of structural and CFD analysis on three-dimensional model of microneedle
array. The effect of axial and transverse loading on the microneedle during skin insertion is investigated in the stress analysis.
The analysis predicts that the resultant stresses due to applied bending and axial loads are in the safe range below the yield
strength of the material for the proposed design of the microneedles. In CFD analysis, fluid flow rate and pressure drop in
the microneedles at applied inlet pressures are numerically and theoretically investigated. The CFD analysis predicts uniform
flow through the microneedle array for each microneedle. Theoretical and numerical results for the flow rate and pressure
drop are in close agreement with each other, thereby validating the CFD analysis. For the proposed design of microneedles,
feasible fabrication techniques such as micro-hot embossing and ultraviolet excimer laser methods are proposed. The results
of the present theoretical study provide valuable benchmark and prediction data to fabricate optimized designs of the polymeric,
hollow microneedles, which can be successfully integrated with other microfluidic devices for TDD applications. 相似文献
88.
Saeed Hafiz Hassaan Ashraf Muhammad Haseeb Kamiran Faisal Karim Asim Calders Toon 《Language Resources and Evaluation》2021,55(4):971-996
Language Resources and Evaluation - With the increasing popularity of user-generated content on social media, the number of toxic texts is also on the rise. Such texts cause adverse effects on... 相似文献
89.
Basudev Pradhan Ashwani K. Sharma Asim K. Ray 《Journal of Materials Science: Materials in Electronics》2009,20(3):267-271
Two types of suitably substituted organic dye molecules namely copper phthalocyanine and Rose Bengal were electrostatically
self-assembled on gold-coated glass substrates, the gold surface being modified with poly(allylaminehydrochloridethe). The
surface plasmon resonance technique was employed to investigate the sensing properties of organic dyes on exposure to three
different volatile organic compounds. The films using phthalocyanine molecules were considered to be an optimal material because
of its fast response and full recovery. This behaviour is attributed to the film surface morphology, molecular orientation
in the film architecture, and sizes and dipole moments of vapours. 相似文献
90.