Volume 5, Issue 9, September 2014

Advanced Materials World Congress (AMWC) - 2015, Sweden  

Ashutosh Tiwari

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 485-485
DOI: 10.5185/amlett.2014.9001

We are pleased to announce next Advanced Materials World Congress (AMWC), 23-26 August, 2015, www.vbripress.com/amwc. It is a four-day international event organised by the International Association of Advanced Materials and sponsored by the VBRI Press, which usually meets every two-year. The upcoming world congress is going to host in the city of Nobel Prize, Stockholm, Sweden. The venue of congress will be held on the Baltic Sea from Stockholm (Sweden) – Tallinn (Estonia) - Stockholm (Sweden) via Mariehamn and Helsinki, Finland by the Viking Line.

A Review On Tribology Of Surfaces And Interfaces

Ram Krishna Upadhyay; Lakshmi Annamalai Kumaraswamidhas

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 486-495
DOI: 10.5185/amlett.2014.5566

Tribological study includes surface interaction and mechanism involve between contacts. At contact points, surface forces affect the geometry and properties of material whereas stress concentration affects processes that involve during friction interactions. Nanomechanical behaviour of thin-film and surfaces has been largely studied during past years in the field of electronics industry such as microelectronics, optoelectronics application, aerospace industry, iron and steel industries and also adapted in the field of biological sector that likely to grow in near future extensively. High resolution microscope and computational techniques enable the material to investigate their interfacial problems at nanoscale. In this, we studied mechanism of tribology, with different deposition technique and their mechanical properties.

Influence Of Air Annealing On The Structural, Morphology And Optical Properties Of ZnSe Thin Films By CW-CO2 Laser Evaporation

Wuttichai Phae-ngam; Taswal Kumpeerapun;Voravit Kosalathip; Suebtarkul Suchat

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 496-500
DOI: 10.5185/amlett.2014.4577

 CW-CO2 laser evaporation was used to deposit ZnSe thin films onto glass microscope slides. The films prepared were annealed in air at annealing temperatures of 100, 200 and 300°C. The effect of annealing temperature on the surface morphology, crystal structure and optical properties was investigated. All samples were seen to have an homogeneous surface morphology. The as-deposited and low temperature annealed ZnSe films exhibited the cubic phase. As the annealing temperature increased, a hexagonal phase developed and at 300°C the ZnO phase began to appear. The average crystallite size of ZnSe films increased from 23.84 to 49.64 nm on annealing at 200°C. Dislocation density, strain in the film and film thickness decreased when the annealing temperature increased up to 200°C. The optical band-gap of the as-deposited film was 2.76 eV decreasing to about 2.70 eV at the 200°C anneal. The introduction of the ZnO phase at 300°C decreased crystallite size whereas it increased film strain. This work shows an easy and economical way to control band gap, crystallite size and film strain in ZnSe thin films by annealing in air. The lack of a pre-heated substrate and the ability to control band gap energy by annealing provides a versatile alternative source of ZnSe film deposition for potential optoelectronic applications.

Green Syntheis Of Silver Nanoparticles And Its Activity On SiHa Cervical Cancer Cell Line

Anal K. Jha; K. Prasad

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 501-505
DOI: 10.5185/amlett.2014.4563

 Biosynthesis and characterizations of nanoparticles has become an important branch of nanotechnology nowadays. In this paper, green synthesis of silver nanoparticles (AgNPs) using the alcoholic extract of Argemone mexicana Linn. as a reducing and stabilizing agent, has been discussed. This biosynthetic method is simple, cost-effective and reproducible. Formation of AgNPs was established by X-ray diffraction, transmission electron microscopy and UV-Visible spectroscopic techniques. Nanoparticles almost spherical in shape having a size of 2-6 nm are found. UV-visible study revealed the surface plasmon resonance at 414 nm. A possible involved mechanism for the biosynthesis of silver nanoparticles has also been proposed.  Further, it was found that AgNPs sol when applied to the SiHa cancer cell line was found to inhibit the growth by 70-80%. It is cumulative effect of the unutilized plant extract and nanosilver. The work signifies the importance of medicinal plants in synthesis of nanomaterials as it bestows double benefit in terms of drug delivery as well as safety. It may open a fresh avenue in future cancer therapeutics.

Thermal Spraying, Optimization And Characterization Of Abradable Seal Coating For Gas Turbine For Service Temperature Up To 750° C

M. Shadab Siddiqui; Pankaj Joshi; N. Nayak; K. Vidyasagar

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 506-510
DOI: 10.5185/amlett.2014.588

In thermal power plants, significant improvements in overall efficiencies can be achieved by reducing the leakage flows in compressor and turbine sections. One way to minimize these leakages is by the use of thermally sprayed abradable sealing coatings. This paper discusses the development of abradable coating for gas turbine shroud segments for service temperatures up to 750 ºC. The abradable coating is developed using plasma coating technique. Effects of coating properties on changing the coating parameters are also discussed. Porosity, bond strength, micro hardness, erosion and abradability tests were performed over the plasma coated samples. Porosity, bond strength, micro hardness and erosion tests results were coming within the bracket suggested by the previous researchers; however abradability tests were not upto the mark. An in house abradability test rig was developed and abradable testing at room temperature was performed using this rig. The results obtained with the abradable test rig were not upto the mark and more testing and analysis is currently being performed to achieve more satisfactory results with the test rig.

Effect Of Laser And Visible Light Irradiation On Structural And Optical Properties Of Thin Films Of Amorphous Selenium And Selenium Mercury (80:20 Composition)

Shabir Ahmad; Mohsin Ganaie; Mohd. Shahid Khan; M. Zulfequar

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 511-519
DOI: 10.5185/amlett.2014.590

This study is carried out the effect of laser and solar light irradiation on the structural and optical properties of amorphous Selenium and selenium mercury (80:20 composition). Bulk samples were prepared by thermal quenching technique and thin films were papered by thermal evaporation technique on glass substrates. Thin films of a-Se and a-SeHg were irradiated by diode laser (wavelength=405nm, power=100mW) and solar light (energy ~ 0.3MeV calculated by E =hc/λ) for different durations of time. XRD analysis of a-Se and a-SeHg show increase of peak intensity and crystallite size after irradiation indicates the enhancement of crystallinity. Raman analysis of a-Se and a-SeHg also favors this improvement of crystallinity after laser and solar light irradiation. The UV analysis shows the value of optical band gap of a-Se and a-SeHg decreases after irradiation (both laser and solar light). Also it was found that the value of Urbach’s energy decreases after laser and solar light irradiation indicates that the disorder has been reduced after irradiation. The other optical parameters like extinction coefficient and absorption coefficient changes accordingly discussed in this study. It was also found that the change of structural and optical parameters is much more in case of solar light irradiation.

Green Synthesis, Characterization And Optical Properties Of Zinc Oxide Nanosheets Using Olea Europea Leaf Extract

Akl M. Awwad; Borhan Albiss; Ahmad L. Ahmad

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 520-524
DOI: 10.5185/amlett.2014.5575

In this paper, a green method is reported for synthesis and characterization of zinc oxide nanosheets using Olea europea leaf extract. ZnO nanosheets were characterized by UV-vis absorption spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The UV-vis absorption spectrum shows an absorption band at 374 nm due to ZnO nanosheets. XRD characterize the final product as highly crystalline ZnO with sizes in the range 18-30 nm. The SEM results reveal a presence of network of randomly oriented ZnO nanosheets or nanoplatelets with an average size of 500 nm and thicknesses of about 20 nm. This facile and green approach may provide a useful tool to large scale synthesis other nanoparticles that have potential biotechnology.

Elastic Plastic Fracture Toughness Of Aluminium Alloy AA6061 Fly Ash Composites

Ajit Bhandakkar; R. C. Prasad; Shankar M. L. Sastry

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 525-530
DOI: 10.5185/amlett.2014.5571

Aluminium fly ash metal matrix composites (MMCs) find important applications in aerospace and automobiles where specific stiffness is important. Low cost fly ash and silicon carbide reinforcement are widely used in aluminium metal and matrix composite due to its low density, high young modulus and strength apart from good mechanical and chemical compatibility & thermal stability. However the MMCs often suffer from low ductility, toughness and fatigue crack growth resistance relative to the matrix alloy. Linear elastic fracture mechanics (LEFM) has been used to characterize the plane strain fracture toughness using various specimen geometries and notches but very few studies using EPFM are reported in literature. In the present paper the influences of weight fraction of particulate reinforcement on tensile, fracture toughness have been evaluated. The tensile strength of aluminium fly ash composites increases with the addition of fly ash reinforcement. However the fracture toughness (KIC) of the aluminium fly ash composite decreases that of base alloy. The fracture toughness KQ of AA6061 ALFA composites varied between 13-14 MPa/m as compared to 18 MPa/m for the re-melted base alloy. Similarly the Elastic plastic fracture toughness JQ for the base alloy AA6061 lies is the range of 20-23 kJ/m 2 and that of composites in the range 6-16 kJ/m 2 . The fracture behavior and micro-mechanism of failure in base alloy and composites have been observed under SEM and optical microscopy.

Dielectric And Impedance Spectroscopic Studies Of Multiferroic BiFe1-xNixO3

M. R. Biswal; J. Nanda; N. C. Mishra; S. Anwar; A. Mishra

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 531-537
DOI: 10.5185/amlett.2014.4566

Multiferroic bismuth ferrites (BFO) and Ni substituted bismuth ferrites (BFNO) were synthesized by standard solid state reaction route. The structural and microstructural studies were carried out. The effect of Ni substitution on dielectric constant and dielectric loss of the samples was studied in a wide range of frequency (100 Hz- 1 MHz) and temperature (27 o C – 420 o C). It has been observed that the dielectric constant increases with increase in Ni doping concentration and attained a maximum value for BFNO(x = 0.075) sample while the dielectric loss has been found to decrease with the doping concentration. This implies a reduction in the conductivity and hence improved the dielectric properties of Ni doped BFO. The anomalous peaks in temperature dependent dielectric studies indicate the increase in antiferromagnetic ordering temperature and possible existence of spin glass states upon Ni substitution in place of Fe. The complex impedance spectroscopic analysis suggests purely the intrinsic nature of the dielectric anomalies. Temperature dependent non-Debye type of dielectric relaxation has also been observed. The Nyquist plots show the negative temperature coefficient of resistance behavior of these compounds. Further it would be interesting to study their magnetic and magnetoelectric properties with the aim of identifying new multifunctional device applications.

Bio- Polymer Assisted Solvothermal Growth And Optical Characterization Of CdS Nanostructures

J. S. Roy; K. Pal; T. Pal Majumder

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 538-542
DOI: 10.5185/amlett.2014.4561

Various nanostructured CdS samples have been synthesized with assistance of starch (bio-polymer) by solvothermal method. We have synthesized nano-regime, nanorods and nanoparticles by simply changing the starch-solvent combinations. The highly polymeric (branched) structure of starch capped the CdS samples to modify the surfaces and hence tune the optical properties. The optical band gaps for three samples are 2.34, 2.37 and 2.38 eV. The photoluminescence emission peak also changes with surface modification of the nanomaterials. The sensitivity of the optical properties of CdS nanomaterials with structural modification by means of polymer may be used for practical application like solid state lighting.

Effect Of Catalyst Concentration On The Synthesis Of MWCNT By Single Step Pyrolysis

B. V. Mohan Kumar; R. Thomas; A. Mathew; G. Mohan Rao; D. Mangalaraj; N. Ponpandian; C. Viswanathan

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 543-548
DOI: 10.5185/amlett.2014.592

Multiwall carbon nanotubes (MWCNT) are synthesised by cost effective method of pyrolysing xylene (as hydrocarbon, precursor) in the presence of ferrocene (as catalyst) at 750 o C. The so obtained MWCNTs has a length ranging from 90 µm to 300 µm and diameter ranging from 20 nm to 200 nm depending on the amount of ferrocene added to the xylene for the synthesis. The diameter of the MWCNT’s increased with the increase in ferrocene content in the precursor solution. Bigger agglomerates of iron particle lead to the growth of larger diameter MWCNTs. These MWCNTs with higher concentration of iron nanoparticles in it are useful for catalytic applications. X-ray diffraction (XRD) of the as-synthesised MWCNTs showed a graphitic-like peak (002). Field emission scanning electron microscope (FESEM) is utilized for its morphological analysis, Raman analysis showed the presence of D band (about 1350 cm -1 ) and G band (about 1580 cm -1 ) indicating high crystalline graphitic layers. Fourier transform infrared (FTIR) studies in the transmission mode were carried out in the range 400 - 4000 cm -1 (peaks at 1386, 1639, 2363, 3434, 3747 cm -1 etc.) for bond stretching analysis. All the characterization processes were carried out before and after purification process. The MWCNT’s diameter and their distribution are studied with the help of ImageJ software using the FESEM micrographs.