Ultrasound assisted one pot synthesis of nano-sized CuO and its nanocomposite with poly(vinyl alcohol)

The ultrasound (US) assisted one pot method has used to synthesize CuO nanoparticles. The fourier transform infrared spectroscopy (FTIR) spectrum shows a characteristic peak of metal–oxygen bond at 535 cm⁻¹, which confirms the CuO formation. The high resolution transmission electron microscope (HRTEM) images of the synthesized nano-CuO confirms the size of nanorods with the length of approximately 25–30 nm, and its breadth is less than one nanometer. X-ray diffraction (XRD) pattern of CuO can be readily assigned to those of crystalline CuO, indicating the formation of single-phase CuO with monoclinic structure. The synthesized nano-CuO is mixed with poly(vinyl alcohol) (PVA) to prepare the PVA/CuO nanocomposite to improve the thermal stability of PVA. Their physico-chemical properties are examined by means of FTIR, XRD, differential scanning calorimetry, thermogravimetric analysis, HRTEM, and scanning electron microscope (SEM) techniques.     

Use of cellulose-based wastes for adsorption of dyes from aqueous solutions

Low-cost banana and orange peels were prepared as adsorbents for the adsorption of dyes from aqueous solutions. Dye concentration and pH were varied. The adsorption capacities for both peels decreased in the order methyl orange (MO) > methylene blue (MB) > Rhodamine B (RB) > Congo red (CR) > methyl violet (MV) > amido black 10B (AB). The isotherm data could be well described by the Freundlich and Langmuir equations in the concentration range of 10-120 mg/l. An alkaline pH was favorable for the adsorption of dyes. Based on the adsorption capacity, it was shown that banana peel was more effective than orange peel. Kinetic parameters of adsorption such as the Langergren rate constant and the intraparticle diffusion rate constant were determined. For the present adsorption process intraparticle diffusion of dyes within the particle was identified to be rate limiting. Both peel wastes were shown to be promising materials for adsorption removal of dyes from aqueous solutions.     

Room temperature processing of epoxy-clay nanocomposites

Polymer/Clay nanocomposites consisting of an epoxy matrix filled with nanolayered silicate clay particles have been investigated. Recent and ongoing research has shown that dramatic enhancements can be achieved in mechanical and thermal properties by adding a small volume percent of clays. In the present work nanocomposites are processed by mechanical mixing of epoxy with organoclays and unmodified clays using a high speed electric shear mixer at room temperature. The addition of different organoclay wt% [1–3, 5 and 10] indicates good enhancement in hardness, dynamic mechanical properties, and also the molecular mobility of the polymer is reduced by the presence of the silicate layers, which in turn causes large stiffness improvements. X-ray diffraction (XRD) results show the intercalation/exfoliation of clays in the epoxy matrix. The influence of organoclay restricts the weight loss at varying temperatures. Experiments show improved elastic modulus for both modified and unmodified clays.     

Computer simulation for prediction of performance and thermodynamic parameters of high energy materials

A new code viz., Linear Output Thermodynamic User-friendly Software for Energetic Systems (LOTUSES) developed during this work predicts the theoretical performance parameters such as density, detonation factor, velocity of detonation, detonation pressure and thermodynamic properties such as heat of detonation, heat of explosion, volume of explosion gaseous products. The same code also assists in the prediction of possible explosive decomposition products after explosion and power index. The developed code has been validated by calculating the parameters of standard explosives such as TNT, PETN, RDX, and HMX. Theoretically predicated parameters are accurate to the order of +/-5% deviation. To the best of our knowledge, no such code is reported in literature which can predict a wide range of characteristics of known/unknown explosives with minimum input parameters. The code can be used to obtain thermochemical and performance parameters of high energy materials (HEMs) with reasonable accuracy. The code has been developed in Visual Basic having enhanced windows environment, and thereby advantages over the conventional codes, written in Fortran. The theoretically predicted HEMs performance can be directly printed as well as stored in text (.txt) or HTML (.htm) or Microsoft Word (.doc) or Adobe Acrobat (.pdf) format in the hard disk. The output can also be copied into the Random Access Memory as clipboard text which can be imported/pasted in other software as in the case of other codes.     

Establishment of process technology for the manufacture of dinitrogen pentoxide and its utility for the synthesis of most powerful explosive of today--CL-20

This paper reviews the recent work done on the synthesis as well as characterization of dinitrogen pentoxide (DNPO). The physico-chemical characteristics of DNPO are also discussed. The review brings out the key aspects of N2O5 technology with relevance to realize modern and novel HEMs. The paper also includes the aspects related with establishing the synthesis facility of dinitrogen pentoxide at HEMRL by gas phase interaction of N2O4 with O3. The process parameters for the synthesis of N2O5 at 50 g/batch have been optimized. The synthesized dinitrogen pentoxide has been characterized by UV [204, 213, 258 nm (pi-->pi*) 378 and 384 nm (n-->pi*)] and IR (1428, 1266, 1249, 1206, 1044, 822, 750, 546 and 454 cm(-1)) spectroscopy. The DSC clearly showed the sublimation of N2O5 at 32 degrees C. The nitration studies on 2,6,8,12-tetraacetylhexaaza tetracyclo[5,5,0,0(3,11)0(5,9)]dodecane (TAIW) proved its viability in 2,4,6,8,10,12-hexanitro-2,4,6,8(10,12))-hexaazatetracyclo [5,5,0,0(3,11)0(5,9)]dodecane (CL-20) synthesis. The synthesized CL-20 and its precursors have also been subjected to hyphenated TG-FTIR studies to understand decomposition pattern.     

Electrospun polyurethane and soy protein nanofibres for wound dressing applications

In this report, a novel wound dressing material has been woven by electrospinning technique and tested for its various properties. For the nanofibre mat, a mixture of polyurethane (PU) and soy protein isolate (SPI) was electrospun in conjugation with zinc oxide nanoparticles (ZnO Nps) and ciprofloxacin hydrochloride (CipHCl) to produce fibrous mats viz. PU/SPI/ZnO and PU/SPI/CipHCl. An optimum ratio (1 : 1) of PU/SPI was used as suitable polymeric ratio in order to produce homogenous nanofibres without beads having an average diameter in the range of 300–350 nm. The electrospun nanofibre‐based mats were characterised using X‐ray diffraction, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, thermogravimetric analysis and scanning electron microscope. The mechanical properties of the nanofibrous mats were tested using universal testing machine. The wettability analysis was done using the contact angle measurement based on the sessile drop test. This study revealed that the electrospun PU/SPI‐based nanofibres are non‐sensitizing, non‐allergic and non‐toxic and that it can be used as a peculiar wound healing material.Inspec keywords: polymer fibres, nanofibres, nanomedicine, biomedical materials, wounds, electrospinning, zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanoparticles, nanofabrication, X‐ray diffraction, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, thermal analysis, scanning electron microscopy, wetting, contact angle, toxicologyOther keywords: electrospun polyurethane nanofibres, soy protein nanofibres, wound dressing applications, electrospinning, nanofibre mat, soy protein isolate, zinc oxide nanoparticles, ciprofloxacin hydrochloride, X‐ray diffraction, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, thermogravimetric analysis, scanning electron microscope, mechanical properties, universal testing machine, wettability, contact angle measurement, sessile drop test, nonsensitizing nanofibres, nonallergic nanofibres, nontoxic nanofibres, wound healing material, wavelength 300 nm to 350 nm, ZnO     

Application specific thresholding scheme for handover reduction in 5G Ultra Dense Networks

Telecommunication Systems - Traditional multi-criteria decision making (MCDM) algorithms are used in the handover of user equipment (UE) in an Ultra Dense Network (UDN). UDN refers to the increased...     

Biosorption potential of Lysinibacillus fusiformis KMNTT-10 biomass in removing lead(II) from aqueous solutions

The biosorption and detoxification performance of Lysinibacillus fusiformis KMNTT-10 biomass for lead(II) was investigated. The optimum conditions for Pb(II) adsorption were found to be pH 6.0 and contact time 90 min at 27 ± 2°C. Equilibrium data of Pb(II) adsorption fitted well with the Langmuir isotherm model and followed pseudo-second-order model. SEM-EDX analysis revealed a blister like protrusions formed on the biomass surface after Pb(II) biosorption. FTIR spectra indicated that anionic functional groups on the biomass surface took part in the adsorption process. Further, X-ray diffraction analysis showed that the adsorbed Pb(II) was transformed (detoxified) into less soluble PbS (galena).     

Spatial modulation and physical layer network coding based bidirectional relay network with transmit antenna selection over Nakagami‐m fading channels

In this paper, a high data rate bidirectional relay network is proposed by combining the merits of spatial modulation (SM) and physical layer network coding. All nodes in the network are equipped with multiple antennas. Spatial modulation technique is used to reduce hardware complexity and interchannel interference by activating only one antenna at any time during transmission. In the proposed bidirectional relay network, transmit antennas are selected at the source nodes and relay node on the basis of the order statistics of channel power. It increases received signal power and provides a significant improvement in the outage performance. Also, the data rate of the proposed network is improved by physical layer network coding at the relay node. A closed form analytical expression for the outage probability of the network over Nakagami‐m fading channel is derived and validated by Monte Carlo simulations. In addition, asymptotic analysis is investigated at high signal‐to‐noise ratio region.The outage performance of the proposed network is compared with SM and physical layer network coding bidirectional relay network without transmit antenna selection and point‐to‐point SM. With approximate SNR≈1 dB difference between the two networks, the same data rate is achieved.     

Measurement of whole‐body vibration exposure from unsuspended cabin tractor semi‐trailers

Indian tractor semi‐trailer drivers are exposed to mechanical whole‐body vibration during their work. Some drivers suffer from low‐back pain from this vibration. However, there is no evidence of a relationship between the whole‐body vibration from tractor semi‐trailers and low‐back pain or occupational disease because of the lack of investigations. A field study was conducted to characterize the health risks associated with driving tractor semi‐trailers. Studies were conducted at different loadings and on different road surfaces as well as at different speeds, with the vibrations measured at the driver–seat interface on x‐longitudinal, y‐transverse and z‐vertical axes. The vibrations were compared with the health‐risk guidance according to Annex B of ISO 2631‐1 (ISO 2631/1, 1997). The findings of this study indicated that Indian tractor semi‐trailer drivers should not operate continuously more than 4 h a day under current working conditions. © 2011 Wiley Periodicals, Inc.