Controlling the length scale and distribution of the ductile phase in metallic glass composites through friction stir processing

We demonstrate the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing (FSP) of titanium based in situ ductile-phase reinforced metallic glass composite. The average size of the dendrites was reduced by almost a factor of five (from 24 μm to 5 μm) for the highest tool rotational speed of 900 rpm. The large inter-connected dendrites become more fragmented with increased circularity after processing. The changes in thermal characteristics were measured by differential scanning calorimetry. The reduction in crystallization enthalpy after processing suggests partial devitrification due to the high strain plastic deformation. FSP resulted in increased hardness and modulus for both the amorphous matrix and the crystalline phase. This is explained by interaction of shear bands in amorphous matrix with the strain-hardened dendritic phase. Our approach offers a new strategy for microstructural design in metallic glass composites.     

Asia: identity,architecture and modernity

This paper argues the need to widen the discourse of modern architecture through an exploration of modern(ities) in Asia, and posits that modern(ities) of East and West are intertwined. The constructed and contested nature of identities, through the medium of colonial exhibitions, is discussed. Using Japan and India as examples, the paper examines the notion of one, none or many modernities and argues that there are multiple alternative modern(ities) that need to be theorised for different locations. The alternative modernities and their dilemmas are posited as being linked to postcolonial constructions of identities, albeit in different ways and in different Asian contexts. The Asian architect, while being both the product and subject of different types of historical lineages and power constellations, has been a key agent in the manifestations of modernity in different locations.     

Breeding of Pleurotus florida (oyster mushroom) for phenotypic pigmentation and high yield potential

BACKGROUND: Cross‐hybridisation is a technique for exchange of genetic material between two compatible nuclei to develop a recombinant genome with a probable expression for a desirable trait. This technique as an example of classical genetics has been applied in a heterothallic bifactorial/tetrapolar fungus Pleurotus florida. It has worked successfully during this study in a small number of experiments. RESULTS: Fruit bodies from the Pleurotus florida PAU‐5 were allowed to shed their basidiospores on filter paper under aseptic conditions. Forty‐nine monokaryons were isolated from three spore prints, namely Ja, Jb and K. Three hundred and fifty‐six crosses were laid to result in five compatible reactions (PFJ4, PFJ9, PFJ11, PFJ13 and PFJ14). The fruit bodies of the hybrid dikaryon PFJ4 were found to show grey pigmentation. The hybrid dikaryons PFJ11 and PFJ14 grew faster in wheat straw substrate to take 39 and 41 days, respectively, for complete mycelial impregnation as compared to the parent, PAU‐5 (48 days). The dikaryon PFJ11 out‐yielded the parent by giving 34.2% biological efficiency compared to 29.8% for the parent. CONCLUSION: Through cross‐hybridisation various changes at the genetic level are possible, showing altered phenotypic expression of the characters, such as change in fruiting efficiency and variability in fruit body characteristics (e.g., pileus shape and pigmentation). This technique can also be applied to other crops to improve their yield potential and bring about desirable phenotypic changes. Copyright © 2008 Society of Chemical Industry     

Theoretical study on the nature of S···H and O ··· H hydrogen bonds

Hydrogen bond acceptor ability of sulfur and oxygen has been analyzed in the adducts of dimethyl sulfide ((CH₃)₂S) and dimethyl ether ((CH₃)₂O) with H₂O, CH₃OH, HCOOH, NH₂OH, CH₃NH₂, NH₂NH₂, HCONH₂, HF and HCl. The stabilization energies have been evaluated using MP2/aug-cc-pVDZ, B3LYP/aug-cc-pVDZ, gaussian2 (G2) and complete basis set (CBS) theoretical levels. The contributors to stabilization energies are explored by employing symmetry adapted perturbation theory analysis, natural bond orbital analysis in addition to molecular orbital methods. Electrostatic component is the major contributor toward stabilization energy in both the type of adducts involving (CH₃)₂S and (CH₃)₂O which has been assigned to secondary electrostatic interactions. The second important contributor to comparable stabilization energies in the two series is the repulsive E_exch component which is relatively higher in adducts of (CH₃)₂O because of the relatively longer proximity of the monomeric units arising from smaller size of oxygen.     

Modelling joint outsourcing and offshoring decisions

Offshoring and outsourcing have emerged as two most essential and important strategies for the manufacturing firms globally. This has happened due to the relentless forces of competition and globalisation, which has forced modern manufacturing firms to disaggregate themselves and reach for foreign investments, technological inputs through collaboration and cooperation among markets and partners. Outsourcing and offshoring simultaneously has potential to help the firm to meet three strategic goals i.e. ‘efficiency’ through cost minimisation; ‘exploration’ through an access to the right and technologically capable firm vendors/ Suppliers/ players; and ‘exploitation’ from development of global markets. Both outsourcing and offshoring have grown to a great extent either by the number of companies involved or by the number of multiple nations are involved. Hence, addressing both offshoring and outsourcing strategies together can provides value to the supply chain in economical and efficient way. Therefore, this paper is an attempt to model joint outsourcing and offshoring decision integrated with fuzzy-MCDM approaches using fuzzy data to optimise total cost through right selection of suppliers to meet demand of global markets, thus, achieving efficiency, exploration and exploitation. The model addresses qualitative and quantitative criteria in joint decisions and is also illustrated to show the cost effectiveness.     

Amorphous Metallic Alloys: Pathways for Enhanced Wear and Corrosion Resistance

Amorphous metallic alloys are widely used in bulk form and as coatings for their desirable corrosion and wear behavior. Nevertheless, the effects of heat treatment and thermal cycling on these surface properties are not well understood. In this study, the corrosion and wear behavior of two Zr-based bulk metallic glasses were evaluated in as-cast and thermally relaxed states. Significant improvement in wear rate, friction coefficient, and corrosion penetration rate was seen for both alloys after thermal relaxation. A fully amorphous structure was retained with thermal relaxation below the glass transition. There was an increase in surface hardness and elastic modulus for both alloys after relaxation. The improvement in surface properties was explained based on annihilation of free volume.     

Effect of Cryogenic Treatment on AISI M2 High Speed Steel: Metallurgical and Mechanical Characterization

This study aims to present the metallurgical and mechanical characterization of cryogenically treated AISI M2 high speed steel (HSS) in terms of carbide precipitation and wear behavior. The samples of commercially available conventionally quenched and tempered AISI M2 HSS were procured and subjected to cryogenic treatment at two levels ?110?°C (shallow treatment) and ?196?°C (deep treatment) of temperature. The microstructures obtained after cryogenic treatments have been characterized with a prominence to comprehend the influence of cryogenic treatment vis-à-vis conventional quenching and tempering on the nature, size, and distribution of carbides. The mechanical properties such as hardness and wear rate of the specimens have also been compared by performing Rockwell C hardness test and pin-on-disc wear test, respectively. Microstructures, hardness, wear rate and analysis of worn surface reveal the underlying metallurgical mechanism responsible for the improving mechanical properties of the AISI M2 HSS.     

Characterization, Corrosion Resistance, and Cell Response of High-Velocity Flame-Sprayed HA and HA/TiO2 Coatings on 316L SS

The main aim of this study is to evaluate corrosion and biocompatibility behavior of thermal spray hydroxyapatite (HA) and hydroxyapatite/titania bond (HA/TiO₂)-coated 316L stainless steel (316L SS). In HA/TiO₂ coatings, TiO₂ was used as a bond coat between HA top coat and 316L SS substrate. The coatings were characterized by x-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy, and corrosion resistance determined for the uncoated substrate and the two coatings. The biological behavior was investigated by the cell culture studies using osteosarcoma cell line KHOS-NP (R-970-5). The corrosion resistance of the steel was found to increase after the deposition of the HA and HA/TiO₂ bond coatings. Both HA, as well as, HA/TiO₂ coatings exhibit excellent bond strength of 49 and 47?MPa, respectively. The cell culture studies showed that HA-coated 316L SS specimens appeared more biocompatible than the uncoated and HA/TiO₂-coated 316L SS specimens.