Synthesis and characterization of nickel oxide nanoparticles by self-propagating low temperature combustion method

Nickel Oxide (NiO) nanoparticles have been synthesised by self-propagating low temperature Combustion synthesis method using Nickel salt with polyethylene glycol as fuel. As synthesized NiO nanoparticles was characterized by employing Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy dispersive X-ray microanalysis studies (EDAX) techniques and X-ray diffraction (XRD) confirmed the formation of NiO nanoparticles in the range 20 to 40 nm. SEM images clearly shows the NiO particles are in Nano size.&nbsp

Metal Matrix Composites as Potential Armour Materials

To defeat a kinetic energy projectile the armour needs to be extremely hard on the surface, so as to blunt the projectile on initial impact. A ceramic material may be an ideal choice. However, to absorb and dissipate the complete kinetic energy of the projectile, the subsequent material has to be extremely tough with a very high work of fracture. It also needs to be a light weight material to keep the overall weight to a minimum possible value. A fibre reinforced polymer matrix composite can meet the requirement. The innermost laver needs to have a very high ductility so as to avoid any fracture and fragment formation which could be lethal. So it has to be a metallic material. Thus, the application requires a range of properties starting from that of a ceramic and ending with that of a metal. Metal matrix composites (MMCs) are essentially metals reinforced with ceramic reinforcements, which exhibit a combination of properties of both the constituents and could be tailored to suit the requirements. Discontinuously reinforced MMCs also have the added advantage of being amenable to conventional metal forming operations, which makes it easier to produce them in the required shapes. This paper would provide an introduction to MMCs and review the available literature on their evaluation for possible applications as armour materials.It would also present the results of the preliminary studies on the dynamic hardness measurements of discontinuously reinforced aluminium alloy composites which gives a good indication of their potential use as armour materials

Photo-Irradiated Biosynthesis of Silver Nanoparticles Using Edible Mushroom Pleurotus florida and Their Antibacterial Activity Studies

This is a report on photo-irradiated extracellular synthesis of silver nanoparticles using the aqueous extract of edible oyster mushroom (Pleurotus florida) as a reducing agent. The appearance, size, and shape of the silver nanoparticles are understood by UV-visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The X-ray diffraction studies, energy dispersive X-ray analysis indicate that particles are crystalline in nature. Fourier transform infrared spectroscopy analysis revealed that the nanoparticles are covered with biomoieties on their surface. As can be seen from our studies, the biofunctionalized silver nanoparticles thus produced have shown admirable antimicrobial effects, and the synthetic procedure involved is eco-friendly and simple, and hence high range production of the same can be considered for using them in many pharmaceutical applications

Rapid biosynthesis of silver nanoparticles using pepino (Solanum muricatum) leaf extract and their cytotoxicity on HeLa cells

[EN] Within nanotechnology, gold and silver nanostructures have unique physical, chemical, and electronic properties [1,2], which make them suitable for a number of applications. Moreover, biosynthetic methods are considered to be a safer alternative to conventional physicochemical procedures for both the environmental and biomedical applications, due to their eco-friendly nature and the avoidance of toxic chemicals in the synthesis. For this reason, employing bio routes in the synthesis of functionalized silver nanoparticles (FAgNP) have gained importance recently in this field. In the present study, we report the rapid synthesis of FAgNP through the extract of pepino (Solanum muricatum) leaves and employing microwave oven irradiation. The core-shell globular morphology and characterization of the different shaped and sized FAgNP, with a core of 20-50 nm of diameter is established using the UV-Visible spectroscopy (UV-vis), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Zeta potential and dynamic light scanning (DLS) studies. Moreover, cytotoxic studies employing HeLa (human cervix carcinoma) cells were undertaken to understand FAgNP interactions with cells. HeLa cells showed significant dose dependent antiproliferative activity in the presence of FAgNP at relatively low concentrations. The calculated IC50 value was 37.5 mu g/mL, similar to others obtained for FAgNPs against HeLa cells.We thank the Spanish Government (Projects MAT2015-64139-C4-1-R, AGL2015-70235-C2-2-R) and Generalitat Valenciana (Project PROMETEOII/2014/047) for support. R.B. and A.V. are thankful to Svagata.Eu program for their fellowships. The authors also thank the Electron Microscopy Service of the UPV for their support.Gorbe, M.; Bhat, R.; Aznar, E.; Sancenón Galarza, F.; Marcos Martínez, MD.; Herraiz García, FJ.; Prohens Tomás, J.... (2016). Rapid biosynthesis of silver nanoparticles using pepino (Solanum muricatum) leaf extract and their cytotoxicity on HeLa cells. Materials. 9(5). https://doi.org/10.3390/ma9050325S3259

An Eccentric Binary Millisecond Pulsar in the Galactic Plane

Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+0327, a radio pulsar with a rotational period of 2.15 ms in a highly eccentric (e = 0.44) 95-day orbit around a solar mass companion. Infrared observations identify a possible main-sequence companion star. Conventional binary stellar evolution models predict neither large orbital eccentricities nor main-sequence companions around millisecond pulsars. Alternative formation scenarios involve recycling a neutron star in a globular cluster then ejecting it into the Galactic disk or membership in a hierarchical triple system. A relativistic analysis of timing observations of the pulsar finds its mass to be 1.74+/-0.04 Msun, an unusually high value.Comment: 28 pages, 4 figures inc Supplementary On-Line Material. Accepted for publication in Science, published on Science Express: 10.1126/science.115758

PSR J1856+0245: Arecibo Discovery of a Young, Energetic Pulsar Coincident with the TeV Gamma-ray Source HESS J1857+026

We present the discovery of the Vela-like radio pulsar J1856+0245 in the Arecibo PALFA survey. PSR J1856+0245 has a spin period of 81ms, a characteristic age of 21kyr, and a spin-down luminosity Edot = 4.6 x 10^36 ergs/s. It is positionally coincident with the TeV gamma-ray source HESS J1857+026, which has no other known counterparts. Young, energetic pulsars create wind nebulae, and more than a dozen pulsar wind nebulae have been associated with very-high-energy (100GeV-100TeV) gamma-ray sources discovered with the HESS telescope. The gamma-ray emission seen from HESS J1857+026 is potentially produced by a pulsar wind nebula powered by PSR J1856+0245; faint X-ray emission detected by ASCA at the pulsar's position supports this hypothesis. The inferred gamma-ray efficiency is epsilon_gamma = L_gamma/Edot = 3.1% (1-10TeV, for a distance of 9kpc), comparable to that observed in similar associations.Comment: 13 pages, 1 figure, accepted for publication in The Astrophysical Journal Letter

PSR J1856+0245: Arecibo discovery of a young energetic pulsar coincident with the TeV g-RAY source HESS J1857+026

We present the discovery of the Vela-like radio pulsar J1856+0245 in the Arecibo PALFA survey. PSR J1856+0245 has a spin period of 81 ms, a characteristic age of 21 kyr, and a spin-down luminosity Ė p 4.6 x 10 36 ergs s-1. It is positionally coincident with the TeV γ-ray source HESS J1857+026, which has no other known counterparts. Young, energetic pulsars create wind nebulae, and more than a dozen pulsar wind nebulae have been associated with very high energy (100 GeV-100 TeV) γ-ray sources discovered with the HESS telescope. The γ-ray emission seen from HESS J1857+026 is potentially produced by a pulsar wind nebula powered by PSR J1856+0245; faint X-ray emission detected by ASCA at the pulsar\u27s position supports this hypothesis. The inferred γ-ray efficiency is εγ p Lγ/Ė p 3.1 % (1-10 TeV, for a distance of 9 kpc), comparable to that observed in similar associations. © 2008. The American Astronomical Society

Arecibo pulsar survey using ALPHA: Probing radio pulsar intermittency and transients

We present radio transient search algorithms, results, and statistics from the ongoing Arecibo Pulsar ALFA (PALFA) survey of the Galactic plane. We have discovered seven objects through a search for isolated dispersed pulses. All of these objects are Galactic and have measured periods between 0.4 and 4.7 s. One of the new discoveries has a duty cycle of 0.01%, smaller than that of any other radio pulsar. We discuss the impact of selection effects on the detectability and classification of intermittent sources, and compare the efficiencies of periodicity and single-pulse (SP) searches for various pulsar classes. For some cases we find that the apparent intermittency is likely to be caused by off-axis detection or a short time window that selects only a few bright pulses and favors detection with our SP algorithm. In other cases, the intermittency appears to be intrinsic to the source. No transients were found with DMs large enough to require that they originate from sources outside our Galaxy. Accounting for the on-axis gain of the ALFA system, as well as the low gain but large solid-angle coverage of far-out sidelobes, we use the results of the survey so far to place limits on the amplitudes and event rates of transients of arbitrary origin. © 2009. The American Astronomical Society. All rights reserved.

The implementation of decentralised biogas plants in Assam, NE India: the impact and effectiveness of the National Biogas and Manure Management Programme

The Indian Government’s National Biogas and Manure Management Programme (NBMMP) aims to deliver renewable energy services to households across the country by incentivising the deployment of family-sized (<6m3) anaerobic (biogas) digesters. We investigated how NBMMP policy is implemented at three levels, from government and state nodal agency, via private contractors to households. We analysed the scheme across two districts in Assam, north-east India, interviewing stakeholders in rural households, state and non-state institutions. We found a top-down, supply-side approach which enables central government to set targets and require individual states to deploy the scheme. Participation in the NBMMP was found to deliver improved energy service outcomes to a majority of households that can afford to participate, although the level of knowledge and understanding of the technology amongst users was limited. Improved training of householders, and particularly women, is needed in relation to the maintenance of digesters, feedstock suitability and the environmental and potential livelihood benefits of digestate. A policy revision which highlights the contextual and demand-side issues around adopting the technology, may deliver monetary benefits from market competition and enable development of community-focused microfinance schemes to improve the affordability of biogas systems