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Rheological studies on unsymmetrical dimethyl hydrazine-methyl cellulose gelled system have been conducted under varying shear rates in order to establish its flow characteristics. The gel is found to behave as a pseudoplastic thixotrop. The viscosity build-up with respect to time has been traced till apparently a firm gel is set. The viscosity is found to increase with time rapidly in the beginning and minor changes are observed thereafter. The effect of temperature and extent of metal (Al and Mg) loading on apparent viscosity of the gelled system has also been investigated. Both the apparent viscosity and thixotropic character of the virgin gel are found to decrease with increase in temperature. An increase in rate of shear decreases the apparent viscosity significantly. The thixotropic character of the metallized gelled systems is observed to increase with metal content and that they exhibit a shearthinning behaviour too. Power law has been applied to assess the variation of pseudoplastic index n and consistency index K with temperature and metallization. The results reveal that n increases with temperature and decreases with metal loading whereas K shows an opposite trend. The yield value of gelled systems is noted to show decrease with temperature and increase with metal incorporation. 相似文献
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We investigate the oscillatory electro-oxidation of formic acid on platinum in a microchip-based dual-electrode cell with microfluidic flow control. The main dynamical features of current oscillations on single Pt electrode that had been observed in macro-cells are reproduced in the microfabricated electrochemical cell. In dual-electrode configuration nearly in-phase synchronized current oscillations occur when the reference/counter electrodes are placed far away from the micro-electrodes. The synchronization disappears with close reference/counter electrode placements. We show that the cause for synchronization is weak albeit important, bidirectional electrical coupling between the electrodes; therefore the unidirectional mass transfer interactions are negligible. The experimental design enables the investigation of the dynamical behavior in micro-electrode arrays with well-defined control of flow of the electrolyte in a manner where the size and spacing of the electrodes can be easily varied. 相似文献
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The purpose of this study was to determine and compare the bioadhesive profiles of hydroxypropylcellulose (HPC) polymer matrices as a function of Δ9-tetrahydrocannabinol (THC) content. In addition, the effect of processing temperature on the stability of THC and its extent of degradation to cannabinol (CBN) was investigated. A hot-melt cast molding method was used to prepare HPC polymer matrix systems incorporated with THC at 0, 4, 8, and 16 percent. Bioadhesive measurements including peak adhesive force, area under the curve, and elongation at adhesive failure were recorded utilizing the TA.XT2i Texture Analyzer™. Data obtained from these tests at various contact time intervals suggested that the incorporation of THC led to an increase in the bioadhesive strength of the HPC polymer matrices. To determine the stability of THC and the resulting CBN content in the matrices, three different processing temperatures were utilized (120, 160, and 200°C). Post-production High Performance Liquid Chromotography (HPLC) analysis revealed that the processed systems contained at least 94% of THC and the relative percent formation of CBN was 0.5% at 120°C and 0.4% at 160°C compared to 1.6% at 200°C. These findings indicate that the cannabinoid may be a plausible candidate for incorporation into systems utilizing hot-melt extrusion techniques for the development of an effective mucoadhesive transmucosal matrix system for delivery of THC. 相似文献
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Wireless Networks - The high speed railway (HSR) provides more convenience to people, so the main attention is given to provide the reliable communication inside the train. It is the challenging... 相似文献
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Time-domain-finite-wave analysis of engine exhaust systems is usually carried out by means of the method of characteristics.
The theory and the computational details of the stationary-frame method have been worked out in the accompanying paper (part
I). In this paper (part II), typical computed results are given and discussed. A setup designed for experimental corroboration
is described. The results obtained from the simulation are found to be in good agreement with experimental observations. 相似文献
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Mohd Zubair Ansari Mohd Faraz Sandeep Munjal Vikram Kumar Neeraj Khare 《Advanced Powder Technology》2017,28(9):2402-2409
Highly dispersible, uniform size (~7 nm) single-phase Cu2ZnSnS4 nanoparticles have been synthesized by hydrothermal method using non-toxic surfactant (oleic acid). High resolution transmission electron microscopy image indicates good crystallinity of the Cu2ZnSnS4 nanoparticles with the growth along (1 1 2) plane. X-ray photoelectron spectroscopy analyses suggested that the formation of with Cu, Zn, and Sn in +1, +2 and +4 oxidation states. The optical absorption spectrum of Cu2ZnSnS4 nanoparticles exhibits an absorption in the visible region and its optical band gap was found to be ~1.72 eV, which could be much more appropriate for photocatalytic application under visible light irradiation. These Cu2ZnSnS4 nanoparticles have been shown high photocatalytic degradation activity of methylene blue (MB) dye in the presence of visible light irradiation. The rate constant (k) value of Cu2ZnSnS4 nanoparticles is found to be 0.0144 min?1. We have discussed the mechanism of dye degradation process that drives the photocatalytic degradation process. The reusability of the Cu2ZnSnS4 nanoparticles for the dye degradation is also demonstrated. 相似文献
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Nina?OrlovskayaEmail author Mykola?Lugovy Vladimir?Subbotin Oleksandr?Radchenko Jane?Adams Munjal?Chheda James?Shih Jag?Sankar Sergey?Yarmolenko 《Journal of Materials Science》2005,40(20):5483-5490
Boron carbide-silicon carbide ceramic composites are very promising armor materials because they are intrinsically very hard.
However, their fracture toughness is not very high. Their ballistic performance could be significantly increased if the brittleness
of these materials could be decreased. Here we report development of boron carbide-silicon carbide layered ceramics with controlled
compressive and tensile stresses in separate layers. Such B4C-SiC laminates with strong interfaces can provide high apparent fracture toughness and damage tolerance along with high protection
capabilities.
The theory of heterogeneous layered systems was used to develop optimal design parameters allowing the evaluation and maximization
of apparent fracture toughness. The layered composites were designed in a way to achieve high compressive residual stresses
in thin B4C-SiC based layers and low tensile residuals stresses in thick B4C layers. The residual stresses were controlled by the phase composition of layers and the layers thickness. The estimated
apparent fracture toughness was calculated for both three layered and nine layered composites. B4C-30 wt%SiC/B4C laminates were made based on the optimized design for high apparent fracture toughness. Processing of laminates involved
preprocessing of powders, forming green tapes and hot pressing. Work is in progress to measure fracture toughness of laminates,
as well as their strength, hardness and the ballistic performance. 相似文献
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Srishti Munjal Smriti R. Deka Santosh Yadav Preeti Goyal Ashwani K. Sharma Pradeep Kumar 《IET nanobiotechnology / IET》2018,12(6):814
Small molecule‐based amphiphiles self‐assemble into nanostructures (micelles) in aqueous medium which are currently being explored as novel drug delivery systems. Here, naproxen‐polyethylene glycol (N‐PEG), a small molecule‐derived amphiphile, has been synthesised, characterised and evaluated as hydrophobic drug carrier. 1 H, 13 C Nuclear magnetic resonance (NMR), mass spectrometry (MS) and Fourier‐transform infrared spectroscopy (FTIR) confirmed the formation of N‐PEG and dynamic light scattering (DLS) revealed the formation of nano‐sized structures of ∼228 nm. Transmission electron microscope (TEM) analysis showed aggregation behaviour of the structures with average size of ∼230 nm. Biodegradability aspect of the micellar‐structured N‐PEG was demonstrated by lipase‐mediated degradation studies using DLS and TEM. High encapsulation efficiency followed by release in a sustained manner of a well‐known anticancer drug, doxorubicin, demonstrated the feasibility of the new drug delivery system. These results advocate the promising potential of N‐PEG micelles as efficient drug delivery system for specific delivery to cancerous cells in vitro and in vivo.Inspec keywords: cancer, biodegradable materials, cellular biophysics, encapsulation, biomedical materials, drugs, nanofabrication, drug delivery systems, nanomedicine, self‐assembly, nanoparticles, transmission electron microscopy, colloids, molecular biophysics, light scattering, hydrophobicity, biochemistry, enzymes, core‐shell nanostructures, nanocomposites, proton magnetic resonance, Fourier transform infrared spectra, mass spectroscopic chemical analysisOther keywords: hydrophobic drug carrier, nanosized structures, transmission electron microscope analysis, doxorubicin, N‐PEG micelles, core/shell nanoassembly, amphiphilic naproxen‐polyethylene glycol, drug delivery system, small molecule‐based amphiphiles self‐assemble, small molecule‐derived amphiphile, 1 H NMR, 13 C NMR, MS, FTIR, dynamic light scattering, aggregation behaviour, biodegradability aspect, lipase‐mediated degradation studies, encapsulation efficiency, cancerous cells 相似文献
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Agarwal Mohit Munjal Amit Wadibhasme Nilesh Dusane Rajiv 《Wireless Personal Communications》2021,120(4):3057-3069
Wireless Personal Communications - The wireless sensor network (WSN) consist of battery-powered sensor nodes which are self-configured and are deployed for monitoring several physical or... 相似文献