Improving delamination resistance of carbon fiber reinforced polymeric composite by interface engineering using carbonaceous nanofillers through electrophoretic deposition: An assessment at different in-service temperatures

In this article, modification of carbon fiber surface by carbon based nanofillers (multi-walled carbon nanotubes [CNT], carbon nanofibers, and multi-layered graphene) has been achieved by electrophoretic deposition technique to improve its interfacial bonding with epoxy matrix, with a target to improve the mechanical performance of carbon fiber reinforced polymer composites. Flexural and short beam shear properties of the composites were studied at extreme temperature conditions; in-situ cryo, room and elevated temperature (−196, 30, and 120°C respectively). Laminate reinforced with CNT grafted carbon fibers exhibited highest delamination resistance with maximum improvement in flexural strength as well as in inter-laminar shear strength (ILSS) among all the carbon fiber reinforced epoxy (CE) composites at all in-situ temperatures. CNT modified CE composite showed increment of 9% in flexural strength and 17.43% in ILSS when compared to that of unmodified CE composite at room temperature (30°C). Thermomechanical properties were investigated using dynamic mechanical analysis. Fractography was also carried out to study different modes of failure of the composites.     

Fabrication and Characterisation of Rutile-TiO_2 Coatings on Metallic Alloy Substrates

RUTILE-TJO2is a versatile material possessing manyinteresting physical,chemical,optical and dielectricproperties[l].It is also a good tribological material thatcan offer low friction and low wear rate[2,3].However,the application of rutile in the tribological field hasbeen limited to titanium alloys only so far,for example,by thermal oxidation of titanium alloys[4,5].Very fewinvestigations have been directed to the tribologicalapplications of rutile films on substrates other thantitanium al…     

Microstructure and properties of flame sprayed tungsten carbide coatings

This article reports on feasibility experiments carried out with oxy-acetylene spray system with various oxygen to fuel ratios using two different tungsten carbide powders and powder feeding methods, to evaluate the newly developed fused WC, synthesised by transferred arc thermal plasma method. Transferred arc thermal plasma method is more economical and less energy intensive than the conventional arc method and results in a fused carbide powder with higher hardness. The microstructure and phase composition of powders and coatings were analysed by optical and scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Carbon content of the powders and coatings were determined to study the decarburisation of the material during spraying process. Coatings were also characterised by their hardness and abrasive wear. The effects of metallurgical transformation and phase content are related to wear performance. The results demonstrate that the powders exhibit various degree of phase transformation during the spray process depending on the type of powder, powder feeding and spray parameters. The carbon loss during the spray process in excess of 45% resulted in reduced hardness and wear resistance of the coatings. Coatings with high amount of WC and W₂C along with FeW₃C showed higher wear resistance. Thus, coatings of high wear resistance can be produced using fused tungsten carbide powder with WC and W₂C phases, which can be economically synthesised by thermal plasma transferred arc method.     

Combining the evidences of temporal and spectral enhancement techniques for improving the performance of Indian language identification system in the presence of background noise

Language Identification has gained significant importance in recent years, both in research and commercial market place, demanding an improvement in the ability of machines to distinguish between languages. Although methods like Gaussian mixture models, hidden Markov models and neural networks are used for identifying languages the problem of language identification in noisy environments could not be addressed so far. This paper addresses the performance of automatic language identification system in noisy environments. A comparative performance analysis of speech enhancement techniques like minimum mean squared estimation, spectral subtraction and temporal processing, with different types of noise at different SNRs, is presented here. Though these individual enhancement techniques may not yield good performance with different types of noise at different SNRs, it is proposed to combine the evidences of all these techniques to improve the overall performance of the system significantly. The language identification studies are performed using IITKGP-MLILSC (IIT Kharagpur-Multilingual Indian Language Speech Corpus) databases which consists of 27 languages.     

Glycated proteome: From reaction to intervention

Glycation, a nonenzymatic reaction between reducing sugars and proteins, is a proteome wide phenomenon, predominantly observed in diabetes due to hyperglycemia. Glycated proteome of plasma, kidney, lens, and brain are implicated in the pathogenesis of various diseases, including diabetic complications, neurodegenerative diseases, cancer, and aging. This review discusses the strategies to characterize protein glycation, its functional implications in different diseases, and intervention strategies to protect the deleterious effects of protein glycation.     

Water matrix effect on UV photodegradation of perfluorooctanoic acid

The widespread detection of perfluorinated compounds (PFCs) in the water environment has been a concern for the last several years, while effluents from wastewater treatment facilities are the major sources of these compounds. Even advanced oxidation technologies (AOTs) are not useful for mineralization of the compounds due to their very high stability. Photochemical techniques using particularly vacuum UV (VUV) have been found to be very promising in this regard. But the use of VUV in UV-based AOTs has still not progressed much. Moreover, the impact of water quality on PFCs photomineralization is unknown. This investigation aimed to assess photomineralization potentials of perfluorooctanoic acid (PFOA) in ultrapure water (UPW), tap water (TW), surface water and treated wastewater effluent using a reactor setup enabling maximum utilization of VUV emission of low pressure lamp in laboratory batch experiments. Neya River water (NRW) and the Nakahama Wastewater Treatment Plant Effluent (NWWTPE) represented surface water and treated wastewater effluent respectively. Also, tests were carried out in 50% diluted NRW and NWWTPE. PFOA photomineralization in terms of PFOA removal, defluorination and total organic carbon (TOC) removal are discussed. The usefulness of the method for PFOA mineralization in organic-rich wastewaters, and further research needs are also highlighted.     

Comment on ‘Frequency domain identification of Wiener models’, by E.W. Bai, Automatica 39 (2003), 1521–1530

A frequency-domain identification method is proposed by Bai (2003) for Wiener systems. The key component is a phase estimator that gives estimates of the linear subsystem phase for different frequencies. These estimates are then used to identify the whole system. In this note, it is shown that the phase estimator is not generally consistent. Consequently, consistency of the overall identification method is in turn not generally guaranteed.     

Complete relaxation and conformational exchange matrix (CORCEMA) analysis of NOESY spectra of interacting systems; two-dimensional transferred NOESY

A very general procedure entitled complete relaxation and conformational exchange matrix (CORCEMA) analysis has been developed to analyze the 2D-NOESY spectra of interacting systems undergoing multistate conformational exchange. This is an extension of earlier work from this laboratory on the methodological treatment of multistate conformational exchange [Krishna et al., Biopolymers 19, 2003 (1980)] and the theory of transferred NOESY for finite exchange off-rates [Lee and Krishna, J. Magn. Reson. 98, 36 (1992)]. The current theory is based on generalized rate matrices for relaxation and conformational exchange. The CORCEMA algorithm explicitly incorporates intermolecular dipolar cross relaxation between the molecules when they are complexed. It permits an analysis of NOESY intensities for the intra- as well as intermolecular contacts between the interacting molecules under a variety of binding conditions. Its application is illustrated on two examples of transferred NOESY simulations: (1) a two-state system involving a ligand and an enzyme forming a ligand-enzyme complex, and (2) a three-state system in which the ligand-enzyme complex can undergo a conformational transition from an "open state" to a "closed state," and can include conformational changes in both the complexed ligand and the complexed enzyme, such as hinge-bending motions. Simplifying expressions for generalized matrix analyses are derived for three limiting cases of the three-state system. This three-state example is illustrated using a hypothetical model of the hinge-bending motion in a thermolysin-inhibitor complex. It is shown that: (1) The neglect of cross relaxation between the interacting species in their complexed forms can lead to misleading conclusions on the "bound" conformation of the ligand. (2) If protein-mediated spin diffusion is dominant, caution is needed in analyses based on initial slopes alone due to one's inability to identify the exact range of the initial growth curve under poor signal/noise situations. (3) The neglect of conformational changes upon complexation, e.g., hinge-bending motions of the ligand-enzyme complex, can lead to erroneous results on the nature of "bound" conformations of the ligand. In this case, attempts to analyze the transferred NOESY data with a two-state model will result in a "virtual" conformation for the bound ligand. (4) When the hinge-bending rate is slower than the cross relaxation and enzyme off-rates, the bound conformation of a ligand deduced from the transferred NOESY experiment is more likely to represent nonspecific or weak binding in an open state of the enzyme.(ABSTRACT TRUNCATED AT 400 WORDS)     

Design of compact two-port dual-band dual-polarized MIMO antenna for CBRS and WLAN sub-6-GHz applications

This communication presents a compact field de-correlation lines integrated dual band with dual-polarized (LP & CP) multiple-input multiple-output (MIMO) antenna for the fifth generation (5G) sub-6-GHz wireless communication systems. Dual working bandwidths, smaller interelement gaps, and superior isolation within the MIMO components are the distinguishing characteristics that give the proposed MIMO system an aspect of novelty. The modeled MIMO antenna has compact configurations of 20 × 21 × 0.8 mm³. The unit cell consists of a microstrip feed line with optimized rectangular slots branches etched from the radiated patch. The MIMO module is generated by the antiparallel replication of a single unit cell. To enhance the isolation, two rectangular slots are incorporated on the patch between the unit elements, which act as field de-correlation lines. The MIMO identity is supported by diversity performance calculations in terms of ECC, DG, and TARC. Simulated and measured counterparts are found in the agreement.     

A Visible and Near-Infrared Light-Fueled Omnidirectional Twist-Bend Crawling Robot

In recent years, although light-driven soft actuators have attracted intense scientific attention and achieved remarkable progress, the design and construction of an intelligent robotic system with maneuverability, self-adaptability, untethered control, and greater freedom of action, in particular the omnidirectional motion capability on a plane, remains challenging. Herein, four types of photo-thermal fillers and an unprecedented twist-bend actuation mode is introduced into a liquid crystal elastomer-based soft robot. The obtained twist-bend crawling robot not only exhibits in situ rotation, four-way turning, and four-way linear motion under light irradiation with four wavelength bands (520, 655, 808, and 980 nm), but also demonstrates the ability to avoid obstacles in complex geographical environments. This work may bring a new perspective for fabrication and development of soft robots that can adapt to dynamic and complex environmental conditions.