Carbon nanohorn‐graphene nanoplate hybrid: An excellent electrode material for supercapacitor application

This study describes the capacitor behavior of carbon nanohorn (CNH)/graphene nanoplate (GNP) hybrid (CNGN). The well‐CNH‐decorated GNP‐plate electrode materials show high capacitance value (≈677 F/g) and can be extensively used in new generation for energy storage. In the hybrid (CNGN), two nanofillers jointly affect the capacitance behavior and increase the capacitance value of the CNGN hybrid. Homogeneous coating of CNH over the GNP plate plays an effective role to enhance the capacitance behavior of the composite. Field emission scanning electron microscopy and high‐resolution transmission electron microscopy analysis of the composite confirmed the CNH coating on the GNP plate. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42118.     

High-temperature flexural strength of I-CVI processed Cf/SiC composites with variable interphases

The effect of single-layer pyrocarbon (PyC) and multilayered (PyC/SiC)_n=4 interphases on the flexural strength of un-coated and SiC seal-coated stitched 2D carbon fiber reinforced silicon carbide (C_f/SiC) composites was investigated. The composites were prepared by I-CVI process. Flexural strength of the composites was measured at 1200 °C in air atmosphere. It was observed that irrespective of the type of interphase, the seal coated samples showed a higher value of flexural strength as compared to the uncoated samples. The flexural strength of 470 ± 12 MPa was observed for the seal coated C_f/SiC composite samples with multilayered interphase. The seal coated samples with single layer PyC interphase showed flexural strength of 370 ± 20 MPa. The fractured surfaces of tested samples were analyzed in detail to study the fracture phenomena. Based on microstructure-property relations, a mechanism has been proposed for the increase of flexural properties of C_f/SiC composites having multilayered interphase.     

Cost analysis of a two unit repairable system subject to on-line preventive maintenance and/or repair

The purpose of this paper is to carry out the cost analysis of a two-unit repairable system subject to on-line preventive maintenance(PM) and repair. The policy adopted here is that the on-line PM work of the operating unit is undertaken followed by repair work of the failed unit(if any). All the random variables that. arise in the analysis are assumed to be independently and arbitrarily distributed. A mathematical model is developed using semi-regenerative phenomena and system of integral equations satisfied by various state probabilities corresponding to various initial conditions are obtained. An iterative numerical method is used to solve the system of integral equations. A cost function is built based on the expected number of various jobs completed by the server in [0, t].     

Synthesis and phosphorylation of macrophage membrane proteins in protein deficient rat

Changes in the biosynthesis and phosphorylation of rat peritoneal macrophage membrane proteins induced by protein malnutrition have been studied. The results clearly indicate that the biosynthesis of high molecular weight proteins (45-200 kDa) and their phosphorylation are significantly reduced in the macrophages isolated from protein deficient (4% protein-fed) rats compared to the control group fed 20% protein diet. Lipopolysaccharide (LPS) treatment both in vivo and in vitro enhanced the synthesis and phosphorylation of these proteins in both control and protein deficient groups; however, the extent of enhancement was much less in the deficient group. These results indicate that besides the down regulation of these membrane proteins, protein malnutrition seems to make these macrophages less responsive to potent immuno stimulants like LPS.     

Intrinsic characteristics as the interface between CAD and machine vision systems

Computer Aided Design systems are currently being used to drive machine vision analysis. We propose that the set of intrinsic 3-D shape characteristics provided by the CAD system be used to compare representational power of different CAD systems so far as the requirements for machine vision are concerned.     

Dynamic oscillatory shear properties of potentially melt processable high acrylonitrile terpolymers

Polyacrylonitrile (PAN) terpolymers consisting of acrylonitrile/methyl acrylate (AN/MA) systems with added amounts of a termonomer (acid based) were synthesized in an effort to generate melt spinnable carbon fiber precursors. The complex viscosity was measured as a function of time in the temperature range of 200-220 °C, and was found to be dependent on both, the amount, as well as the nature of the termonomer. For the different acid termonomers studied, the cyclization/crosslinking reactions occurring during stabilization as evidenced by the increase in viscosity over time of the PAN system ranged in the order, itaconic acid>acrylamide>methyl acrylic acid>acrylic acid (IA>AM>MAA>AA). Dynamic shear experiments indicated that an AN/MA system containing 3 mol% IA seemed well suited for melt spinning and stabilization. A chemorheological correlation was used to describe the viscosity variation in the PAN system as a function of IA content, temperature and time.     

Effect of comonomers on melt processability of polyacrylonitrile

This work is concerned with the feasibility of achieving melt‐processable polyacrylonitrile copolymer systems as precursors for the manufacture of carbon fibers. Identification of suitable comonomers and achieving the optimum content of the comonomer were some of the main objectives of this investigation. It was seen that methyl acrylate (MA) was found to be suitable for enabling the melt processing of polyacrylonitrile (PAN), in terms of melt viscosity, time stability, and char yield. Below 10 mol % of MA, the PAN copolymer exhibited no flowability, even at very low molecular weights (～ 20,000). The long‐range order inherently present in PAN is speculated to be broken down at a critical value of about 10% MA at 220°C in the PAN‐based system, enabling its melt flowability. It was also seen that the incorporation of MA was seen to improve the temperature and molecular weight window of processability of the PAN system. The molecular weight cutoff for the 90/10 mol % acrylonitrile/methyl acrylate (AN/MA) system was about 50,000 at 220°C, whereas it was increased to about 100,000 in the presence of 15 mol % MA comonomer. Feasibility studies on the use of other comonomers such as higher acrylates and acrylamides were also conducted. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 69–83, 2002     

Damage Assessment of 2.5D C/SiC Ceramic Matrix Composite: Effect of Fibre Off-Axis Orientation

Transactions of the Indian Institute of Metals - 2.5D C/SiC ceramic matrix composite is widely used for thermal protection and hot sections of gas turbine engines. The fibre axis in these...