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In this investigation, an attempt was made to identify quantitative trait locus (QTL)/gene associated with JIP-test parameters in rice. Thirty main effect additive QTLs (M-QTLs) along with more than 500 digenic epistatic QTLs were detected using a backcross-derived population from tolerant genotype Pokkali (AC41585) and the susceptible counterpart IR64. These M-QTLs were located in almost all the chromosomes except chromosome number 6 and 8. Most of the M-QTLs showed pleiotropic effects. Positional similarity of all these overlapping additive and additive × additive interaction, QTLs indicated the substantial resemblance of the genetic basis of many JIP-test parameters which imparted salinity tolerance in rice at the seedling stage. Twenty-three potential functional genes were also delineated inside these additive QTLs regions. The identified putative QTLs for JIP-test parameters and probable functional genes lying therein are useful for imparting greater photosynthetic potential in rice under salt stress. [ABSTRACT FROM AUTHOR]

Functionally graded in-situ A356-Mg 2 Si composites by centrifugal casting method have been studied with varying percentage of extra Mg additions during synthesis. The coarse primary Mg 2 Si particles and the Si morphology in eutectic do not yield appreciable mechanical properties. Solution treatment and artificial ageing (T6) are effective means to improve mechanical properties by refining the as-cast structure with additional formation of very fine precipitates during ageing. The microstructural evolution has been assessed by optical, scanning and transmission electron microscopy and X-ray diffraction analysis. Ageing curves are plotted with hardness versus ageing time. High temperature tensile properties are evaluated at room temperature, 150 °C and 300 °C at different layers of the graded composites and are compared between as-cast and T6 conditions. The tensile fracture mechanisms are explained from fractographs. A remarkable improvement in high temperature tensile strength at 150 °C with adequate ductility is observed in T6 condition with respect to as-cast condition. Image 1 • Functionally graded in-situ A356-Mg 2 Si composites with varying Mg additions are studied. • Microstructure and high temperature mechanical properties in as-cast and T6 are compared. • As-cast coarse eutectic Si is refined and nano-sized β" and β′–Mg 2 Si are formed in T6. • The ageing curves show a double peaks – due to formation of metastable β" and β′ phases. • Remarkable increases in tensile strengths are observed at the inner layers after T6 conditions. [ABSTRACT FROM AUTHOR]

Single crystals of thulium trifluoromethanesulfonate (TmTFMS) were grown and the principal magnetic susceptibility χ⊥ and magnetic anisotropy Δχ(=χ∥-χ⊥) were measured in the temperature range of 300–13.5 K and 300–80 K, respectively. Though the value of χ⊥ is found to rapidly increase with the decrease in temperature, the value of χ∥ slowly increases with the lowering of temperature down to ∼110 K, below which it slowly decreases. The hexagonal crystal structure of TmTFMS is similar to that of the isostructural series of hydrated rare earth ethylsulfates and the non-Kramers Tm3+ ion occupies a site of C3h symmetry. Our observed magnetic data were analyzed using crystal field (CF) analyses where the Hamiltonian includes the atomic free ion and (CF) (one-electron) interaction terms. The computed and measured paramagnetic susceptibilities of TmTFMS agree well in the temperature range of our study. Smooth variation of χ⊥ down to 13.5 K does not indicate any structural phase transition or symmetry breaking, at least down to 13.5 K. The computed nuclear quadruple splitting and electronic heat capacities give some interesting results. In order to substantiate the theoretical calculation, the Raman spectra of the compound were recorded in the wavenumber range of 10–1800 cm-1. It has been found that the theoretical values of the CF Stark energies in the ground multiplet are in good agreement with the Raman data. [ABSTRACT FROM AUTHOR]

Co doped ZnO nanoparticles were synthesized by a simple rheological phase reaction-precursors method using zinc acetate, cobalt acetate, and oxalic acid for different atomic percentages of Co doping. X-ray diffraction studies confirmed the correct phase formation, and the composition were obtained from the x-ray photoelectron spectroscopic studies. Particle size was obtained from the small angle x-ray scattering studies. It was observed that the static dielectric constant, calculated from the shift of band gap energy, shows a gradual decrease with Co doping. A simple theoretical model was developed to explain the observed change of dielectric constant on the doping concentration. The model could successfully describe the dependence of the static dielectric constant on the doping concentration. [ABSTRACT FROM AUTHOR]

Nanocrystalline, p-type semiconducting, transparent CuAlO2 thin films were deposited by direct current sputtering of a prefabricated polycrystalline CuAlO2 target, with deposition time as a variable parameter. Transmission electron micrographs reveal the formation of CuAlO2 nanoparticles. For the films deposited in 3, 9, and 15 min, the average particle sizes are determined to be around 10, 20, and 30 nm, respectively. The interplaner spacings calculated from selected area electron-diffraction patterns obtained from transmission electron microscopy confirmed the proper phase formation of the material. X-ray diffraction measurements of the films deposited for 15 and 45 min show some diffraction peaks, which depict the rhombohedral crystal structure of the material. The band-gap values obtained from the optical transmission and reflection data, for the films deposited in 3 and 9 min, are 3.94 and 3.84 eV, respectively, whereas for those films deposited in 15 and 45 min, the band-gap values lie in the range of 3.72–3.60 eV. These values are quite larger than that of bulk material, which is around 3.34 eV. The particle sizes in these cases are, respectively, 30 and 60 nm. It is well known that quantum confinement in semiconductor nanocrystals leads to the band-gap widening with respect to the bulk material. In this report we have observed an increase in the band gap of the nanostructured p-type semiconducting CuAlO2 thin film with the decrease in the particle size. Room-temperature photoluminescence measurements of this material are reported, which showed an ultraviolet near-band-edge emission around 3.60 eV, which originates from the generation and recombination of electron-hole pairs, namely, excitons. From the semiquantitative arguments it is supposed that the natural layered structure of delafossite CuAlO2 is responsible for the stability of the excitons. Also a blueshift of the emission peaks is observed with a decrease in the particle size, which may be described as another experimental indication of the quantum confinement effect within our nanocrystalline CuAlO2 thin films. The p-type nature of the films was established by hot-probe and thermopower measurements. [ABSTRACT FROM AUTHOR]

Mediation analyses were conducted to explore the contribution of lifestyle behaviours in the ethnic pattern of poor health outcomes in Leicester, England. Cross-sectional study. The study used data on 1959 participants from the Leicester Health and Well-being Survey (2015). Lifestyle behaviours were physical activity, diet, smoking and alcohol drinking. Poor health outcomes were the presence of long-term illness and poor self-reported health. Poor health outcomes were less common in Black and Minority Ethnic groups (BMEs) than Whites. Smoking was less common in BMEs than Whites. Poor health outcomes were more common in ex-smokers and current smokers than never smokers. Health outcomes were associated with smoking even after adjusting for ethnicity. The association of ethnicity and health outcomes reduced after adjusting for smoking, suggesting that the effect was mediated by smoking. In Leicester, Whites had poorer health outcomes than BMEs, which were not mediated by physical activity, diet and alcohol drinking but were mediated by smoking. • Mediation analyses were conducted using data from the Leicester Health and Well-being Survey (2015), England. • In Leicester, Whites had poorer health outcomes than Black and Minority Ethnic groups. • In Leicester, poorer health outcomes were not mediated by physical activity, diet and alcohol drinking but by smoking. [ABSTRACT FROM AUTHOR]

A nanostructured surface layer with average grain size of about 25 nm was developed through ultrasonic shot peening (USSP) on the peak aged and retrogressed aluminium alloy 7075 (AA7075). Thermal stability and other features such as precipitation of hardening particles, grain growth kinetics and microstructural evolution of the nanostructured surface were investigated using XRD and TEM, following annealing at different temperatures from 150 °C to 350 °C. Small peaks of MgZn 2 precipitates were observed in the as USSP treated condition and also after annealing at 150 °C for 30 min. The intensity of these peaks was increased from annealing at 200 °C and the size of precipitates was increased. The nanograins formed from the USSP treatment were thermally stable up to 200 °C, recrystallized at 250 °C and started coarsening at 300 °C, however, the grain size following annealing even at 350 °C was <500 nm. Quantitative evaluation of the different strengthening processes showed that grain boundary strengthening as per the Hall-Petch relationship and dislocation induced hardening based on the Bailey-Hirsch relationship were the dominant mechanisms of strengthening. Unlabelled Image • Substantial grain refinement was resulted from the USSP specimen. • Excellent thermal stability of the nanograins was observed upto 250 °C. • Pinning of the precipitates grain boundaries retarded the grain growth. • Grain boundaries and dislocations dominated the strengthening phenomenon. [ABSTRACT FROM AUTHOR]

Presents a study that measured the electrical conductivity and Hall mobility of CuInSe[sub2] films. Experimental procedures; Results; Discussion.

Reports that electrolyte electroreflectance (EER) experiments were performed on In0.22Ga0.78As/GaAs single quantum wells grown by the conventional molecular-beam-epitaxy (MBE) shutter operation, and also by modified MBE shutter operation. Growth parameters for InGaAs/GaAs SQW samples; Energy band gap of InGaAs/GaAs; Depth profile analysis with etch steps.

The effect of Mg content (2.5 and 7.5 wt%) on the development of centrifugally cast in-situ A356-Mg 2 Si composite functionally graded material (FGM) has been investigated. The secondary dendrite arm spacing (SDAS) has the effect on size and volume% of Mg 2 Si particles. FGMs are characterized by optical and scanning electron microscopy, X-ray diffraction analysis, measurement of hardness and room and elevated temperature tensile properties (UTS). The microstructural features are correlated with room temperature and high temperature tensile properties at 150 °C and 300 °C. Since the population of Mg 2 Si particles are maximum at inner zones, the tensile strengths at these zones are maximum among the three zones. The room temperature tensile strength of FGM with 7.5 wt% Mg shows maximum value however it decreases at higher temperatures. The peak UTS of both FG composites in all three zones are attained at around 150 °C. Maximum peak UTS of 178 MPa is obtained with A356–2.5%Mg at this temperature. As the test temperature is increased, the fracture mode is changed from mixed mode to ductile mode. Particle cracking and decohesion of particles from the softer matrix are responsible for these two modes respectively. [ABSTRACT FROM AUTHOR]

The effect of ultrasonic shot peening (USSP) was studied on microstructural modification in the surface region and low cycle fatigue (LCF) behavior of the Ti–6Al–4V alloy, at room temperature. Nanostructure of 17–25 nm was developed in surface region of the alloy by USSP. Fatigue life of the USSPed samples was found to increase progressively with decrease in strain amplitude to much larger extent in comparison with those of the non-USSPed ones. Fatigue life of the USSPed sample was enhanced by four times at the lowest strain amplitude of ±0.60%. There was cyclic softening from the beginning until the failure, at the high strain amplitudes (Δε t /2≥ ±0.80%) whereas cyclic hardening was exhibited during the initial 100 cycles, followed by softening at the lower strain amplitudes (Δε t /2 ≤ ±0.70%). Deformation structure of the samples, tested at different strain amplitudes was analysed using TEM. The results are discussed in terms of increase in the resistance of the material against crack initiation due to grain refinement in the surface region and the associated compressive stresses induced from USSP. [ABSTRACT FROM AUTHOR]

This investigation addresses the effect of surface nanostructure developed through ultrasonic shot peening (USSP) on corrosion behavior of 7075 aluminum alloy. USSP develops surface nanostructure, induces severe plastic deformation, refines grain size up to certain depth and imparts compressive residual stress in the surface region. The sample USSPed for 15 s (USSP 15) exhibited lower current density (0.564 μA/cm 2 ) and higher corrosion potential (−0.695 V) as compared with that of the un-USSP specimen with 1.269 μA/cm 2 and -0.839 V respectively. The enhancement in corrosion resistance of USSPed sample is due to rapid development of uniform, homogeneous and effective passive layer on the nano-structured surface coupled with refinement of the coarse precipitates. Also, there is optimum combination of surface roughness, compressive residual stress, and dislocation density in the surface region to produce highest corrosion resistance in the USSP 15 condition. [ABSTRACT FROM AUTHOR]

Ultrasonic Shot Peening (USSP) is a novel process of refinement of surface grain to nanoscale and inducing compressive residual stress in surface region of metallic materials. The effect of USSP is studied on microstructure and low cycle fatigue (LCF) behavior of peak aged 7075 aluminium alloy, in the present investigation. The microstructure in surface region of the USSPed specimens is found nanostructured. Phase stability, crystallite size, and lattice strain resulting from USSP are analyzed by X-ray diffraction (XRD). The effect of surface roughness and the compressive residual stress induced by USSP is examined on LCF behavior of the material. Enhancement in LCF life is observed by USSP treatment up to the duration of 180 s, however, fatigue life is reduced from longer duration of USSP for 300 s. The enhancement in LCF life is from combined effects of the surface nanostructure and the associated compressive residual stresses. [ABSTRACT FROM AUTHOR]

Nanostructure of 17 to 25 nm was developed in surface region of the titanium alloy Ti–6Al–4V, up to the depth of ~ 30 μm, by ultrasonic shot peening. The effect of nanostructured surface was studied on corrosion behaviour of this alloy, in three different salt mixtures: 100 wt.% NaCl, 75 wt.% Na 2 SO 4 + 25 wt.% NaCl, and 90 wt.% Na 2 SO 4 + 5 wt.% NaCl + 5 wt.% V 2 O 5 ; at 400, 500 and 600 °C. Specimens were subjected to heating and cooling cycles with different hold periods in three blocks for total exposure of 100 h. The main corrosion products formed in the different salt mixtures were characterized as TiO 2 , Al 2 O 3 , V 2 O 3 , Ti 2 O 3 and V 2 O 5 oxides. The corrosion rate was found to be lower in the ultrasonic shot peened specimens as compared to those in the non-shot peened ones. [ABSTRACT FROM AUTHOR]

Surface nanostructure was induced in Ti–6Al–4V alloy by ultrasonic shot peening (USSP) for different durations, from 15 s to 30 min, and the modified surface was characterized by optical, scanning, atomic force and transmission electron microscopy. Nano size grains were observed to form on surface of the USSPed samples and surface roughness was increased with duration of USSP. Polarization study was carried out in Ringer's solution to examine the effect of surface nanostructuring on corrosion resistance of this alloy. Electrochemical corrosion was carried out for all the USSPed specimens as well as the non-USSPed sample in Ringer's solution. Surface morphology of the corroded samples was examined by SEM. In general, corrosion resistance was improved by USSP up to the duration of 15 min and there was maximum improvement in the specimen USSPed for 1 min. However, corrosion resistance was drastically reduced due to USSP for long duration of 30 min. [ABSTRACT FROM AUTHOR]

LASER shock peening (LSP) is an effective process of surface modification. This work is concerned with the effect of LSP on the modification of microstructure, hardness, microhardness profile, residual stress, tensile properties and corrosion behavior of interstitial free (IF) steel. In order to study the effect of pulse energy on hardness, samples were subjected to LSP at pulse energy of 170, 230, 290 and 340 mJ respectively. The effect of LSP time on hardness, microhardness profile and tensile properties was investigated by processing the samples for 5, 10, 15 and 20 min at pulse energy of 230 mJ and there was found to be significant increase in tensile strength. There was grain refinement to nano level in the surface region due to LSP. Hardness was observed to increase by LSP up to 10 min and tensile strength increased up to LSP of 5 min. However with the increase in LSP time beyond 10 min there was prominent ablation and melting. The effect of overlapped (OV) LASER shocks was also studied by comparing their behavior with that of single shock. The potentiodynamic polarization study showed significant increase in corrosion resistance of the LSPed IF steel. [ABSTRACT FROM AUTHOR]

Abstract: This paper highlights the role of globular microstructure on the weldability of semi-solid processed aluminum alloys via high temperature flow behavior. The investigation was carried out on the joining of thixocast A356 aluminum alloy components by friction welding. A thermomechanical model was developed to predict the temperature and stress distributions, as well as to identify the suitable and safe range of parameters. Good comparisons between numerical and experimental results were observed. In addition, metallographic examinations and hardness and tensile tests of the welded samples were carried out. It was found that the tensile strength of the joint is higher than the tensile strength of the parent material for the optimum set of parameters. [Copyright &y& Elsevier]

Abstract: The paper reports the synthesis of Nb/Si multilayers (48/27nm) deposited on Si single crystal substrate by sequential laser ablation of elemental Nb and Si. Significant amount of Nb is found in the amorphous Si layer (~25–35at.% Nb). The Nb layer is found to be polycrystalline. The phase evolution of the multilayer has been studied by annealing at 600°C for various times and carrying out cross sectional electron microscopic studies. We report the formation of amorphous silicide layer at the Nb/Si interface followed by the formation of the NbSi2 phase in the Si layer. Further annealing leads to the nucleation of hexagonal Nb5Si3 grains in amorphous silicide layers at Nb/NbSi2 interfaces. These results are different from those reported for sputter deposited multilayer. [Copyright &y& Elsevier]

Undoped and phosphorus doped nanocrystalline nickel oxide thin films have been synthesized on silicon and glass substrates by RF magnetron sputtering technique in pure Ar atmosphere. Proper phase formation was confirmed by X-ray diffraction analysis. Energy band gaps were determined using UV-Vis spectra. Formation of NiO nanoparticle of dimension ~15 nm was confirmed using HRTEM. Doping of phosphorus as an impurity was confirmed from EDX spectra and XPS studies. Spectroscopic ellipsometric studies were performed on such films and the spectra were analyzed with a suitable model. Optical constants were determined and refractive indices were found to increase with increase of phosphorus doping percentages. [ABSTRACT FROM AUTHOR]

Resistance spot welding characteristics of martensitic sheet steel (M190) was investigated using a peel test, microhardness test, tensile shear test and fatigue test. Tensile shear test provides better spot weld quality than conventional peel test and hardness is not a good indicator of the susceptibility to interfacial fracture. Unlike DP 600 steel, the maximum load carrying capability is affected by the mode of fracture. At high load low cycle range, weld parameters have a significant difference in the S- N curves. But, almost similar fatigue behaviour of the spot welds is noted at low load high cycle range. However, when applied load was converted to stress intensity factor, the difference in fatigue behaviour between welds and even DP 780 steel diminished. Furthermore, a transition in fracture mode, that is, interfacial and plug and hole type at about 50% of yield load were observed. [* Note: Correction made on 16 Aug 2010 after first publication online on 28 June 2010. The authors' affiliations were corrected. Under Results and Discussion, in reference to the HAZ hazardness in the 'Micro hardness profile' section, Figure 2 was changed to Figure 3. In reference to the welding parameters under 'Tensile properties' section, note that Figure 4 represents 7/200 and Figure 5 represents 5/300. In reference to the low cycles behaviour of S-N curves in the 'Fatigue' section, Figure 5 was changed to Figure 6.] [ABSTRACT FROM AUTHOR]

Mixing time studies were performed on a one-fifth scale aqueous model of a single tapered ladle with different bottom purging locations. Two porous plugs were used simultaneously to purge compressed air as an analogue to argon and this was referred as dual purging. KCl solution (1 N) was used as the tracer for measuring mixing time. The scaled down gas flowrate varied from 10 to 80 L m–1. Around 400 experiments were done including all possible dual purging locations and the location which gives least mixing time was identified. The results were compared with corresponding single purging experiments and it was found that dual purging can reduce mixing time to a great extent even in the lower flowrate range and a location better than ±R/2 has been suggested. Effect of differential flow on mixing time has also been reported. [ABSTRACT FROM AUTHOR]

The material removal rate (MRR), along with the electrode wear rate (EWR), plays an important role in analysing machine output during electrical discharge machining. This work focuses on the improvement of machine output by introducing an induced magnetic field on the workpiece during rotary electrical discharge machining (REDM) of EN-8 steel with a rotary copper electrode. The workpiece was placed inside the induced magnetic field, wherein polarity of the magnetic field gets reversed periodically. Using Taguchi’s recommended design of experiments, we initially conducted experiments with eight input parameters at different levels . Significant parameters were identified with the help of the signal-to-noise ratio and ANOVA. Finally, another set of experiments was conducted for analysis of the process and development of empirical expressions for MRR and EWR. Experimental results established that rotary electrical discharge machining with a polarity reversal magnetic field delivers better machining output than machining in a non-magnetic field. Thus, this work benefits the EDM process by reducing the machining costs and by producing better geometrical trueness on workpieces, as MRR increased and EWR decreased. [ABSTRACT FROM AUTHOR]

Background & objectives: Nicotine intake through tobacco is very common in female population of lower socioeconomic level who are deprived of healthy diet. Women suffer consequences of smoking such as cardiovascular disorder, lung related diseases and oxidative stress, etc. No data are available of the influences of nicotine on lipid profile, lipid peroxidation and antioxidant enzymes levels under restricted dietary protein intake. The present study was carried out to investigate the effect of nicotine on such parameters of female rats fed with protein restricted diet (5% casein) as compared to those with normal protein diet (18% casein) with or without vitamin C or E supplementation. Methods: Subcutaneous injections of nicotine tartrate (3.5 mg/kg body weights per day for 15 days) were given to the rats and subsequent measurements of plasma lipid profile, plasma and ovary lipid peroxidation and antioxidant enzymes were done. Results: The results showed significant (P<0.01) increase of total cholesterol (TC) and more significant (P<0.001) increase of triglyceride and low-density lipoprotein cholesterol (LDL-C) of plasma under both dietary conditions. The increase of plasma very low-density lipoprotein cholesterol (VLDL-C) was highly significant under protein-restricted diet. The high-density lipoprotein cholesterol (HDLC) decreased significantly in both dietary conditions. Lipid peroxidation in plasma increased significantly in protein-restricted condition. Superoxide dismutase and catalase activities in the ovary tissue decreased significantly (P<0.001) by nicotine treatment in both dietary groups. Interpretation & conclusions: Our findings indicated that nicotine-induced toxicity is more in lipid profile (plasma) and lipid peroxidation (plasma and ovary tissue) under protein-restricted diet as compared to that of the normal protein diet. The antioxidant vitamins antagonized the nicotine-induced effects less effectively on the observed parameters under restricted dietary protein. [ABSTRACT FROM AUTHOR]

The formation of an ω-Al7Cu2Fe phase during laser cladding of quasicrystal-forming Al65Cu23.3Fe11.7 alloy on a pure aluminium substrate is reported. This phase is found to nucleate at the periphery of primary icosahedral-phase particles. A large number of ω-phase particles form an envelope around the icosahedral phase. On the outer side, they form an interface with an α-Al solid solution. Detailed transmission electron microscopic observations show that the ω phase exhibits an orientation relationship with the icosahedral phase. Analysis of experimental results suggests that the ω phase forms by precipitation on an icosahedral phase by heterogeneous nucleation and grows into the aluminium-rich melt until supersaturation is exhausted. The microstructural observations are explained in terms of available models of phase transformations. [ABSTRACT FROM AUTHOR]

Abstract: The eutectic morphology of ternary Nb–Si–Mo alloys with hypereutectic (Nb–19Si–5Mo, and Nb–18Si–26Mo) and hypoeutectic (Nb–13Si–4Mo, and Nb–12Si–15Mo) compositions has been examined. The eutectic in these materials has been found to consist of a mixture of Nb solid solution and Nb5Si3 with lamellar or non-lamellar morphology. For similar concentration of Si, the volume fraction of non-lamellar eutectic in the hypoeutectic alloys increases with Mo content. However, the concentration of Mo has little effect on the non-lamellar eutectic content of hypereutectic alloys. Hypereutectic compositions, having higher concentration of Si, show a much larger volume fraction of non-lamellar eutectic compared to that found in the hypoeutectic compositions. The lamellar or non-lamellar character of the eutectic is attributed to the composition-dependent under-cooling behaviour of the ternary Nb–Si–Mo alloys during solidification and their volume fractions in these alloys assist to explain some of the structure–property relations. [Copyright &y& Elsevier]

Single crystals of thulium phosphates (TmPO4) are grown and the principal magnetic susceptibility perpendicular to the symmetry axis ‘c’ of the crystal $$\left( {{\text{ $ \chi $ }}_ \bot } \right)$$ and the magnetic anisotropy $$\Delta {\text{ $ \chi $ }}\left( {{\text{ = $ \chi $ }}_\parallel - {\text{ $ \chi $ }}_ \bot } \right)$$ are measured in the temperature range 300–13.5 K and 300–80 K, respectively. Though $${\text{ $ \chi $ }}_ \bot $$ increases rapidly with the decrease of temperature, $${\text{ $ \chi $ }}_\parallel $$ increases very slowly with the lowering of temperature. The tetragonal crystal structure of TmPO4 is similar to that of Tm3+ in YPO4 and LuPO4 and in all the cases the non-Kramers Tm3+ ion occupies a site of D2d symmetry. Our observed magnetic data on TmPO4 are analyzed using crystal field analysis where the Hamiltonian includes the atomic free ion and crystal field (one-electron) interaction term. The computed and measured paramagnetic susceptibilities of TmPO4 agree very well in the temperature range of our study. The magnetic behaviours of Tm3+ in YPO4 and LuPO4 are also studied and the results are compared with that of TmPO4. In all the cases the natures of thermal variations of average susceptibilities and magnetic anisotropies are mostly governed by the perpendicular susceptibilities as their values are higher and rapidly increase with the lowering of temperature compared to parallel susceptibilities. The computed nuclear quadruple splittings, electronic heat capacities of Tm3+ in three different hosts give some interesting results. [ABSTRACT FROM AUTHOR]

Abstract: The effect of Mo on the structure–property relationships of arc-melted cast in situ composites of Nb solid solution (Nbss) and α-(Nb,Mo)5Si3, with hypereutectic Nb–19.1Si–5.2Mo (A) and Nb–17.9Si–26.3Mo (B), and hypoeutectic Nb–12.8Si–4.1Mo (C) and Nb–12.3Si–14.8Mo (D) compositions has been studied. The influence of Mo concentration on lattice constants and microhardness of the constituent phases has been analyzed. The morphology, volume fraction and size distribution of the primary phase and the eutectic have been critically examined and related to the elastic modulus, hardness and fracture toughness of the composites. Fracture toughness values, determined through three-point bend and indentation tests, increase with higher amount of coarse eutectic but decrease with increasing Mo content. Indentation cracking exhibits R-curve type behaviour, promoted through bridging or arrest of cracks by the coarse Nbss in the eutectic. The study suggests promise for near-eutectic compositions of Nb–Si–Mo ternary system with low concentration of Mo for structural applications. [Copyright &y& Elsevier]

A letter to the editor on "Spontaneous formation of the B2 phase from a decagonal quasicrystal under reduced constraint," by S. H. Kim, K. Chattopadhyay, B. J. Inkson, G. Möbus, W. T. Kim, & D. H. Kim in the August 2006 issue is presented.

The possibility of synthesis of quasicrystalline and associated approximant phases during mechanical alloying and subsequent heat treatment of Al 65 Cu 20 Fe 10 Si 5 alloy powders has been investigated. It is shown that, in addition to the stable ordered quasicrystal and 1/1 cubic approximant, two more phases having orthorhombic symmetry coexist. The a and c parameters of both these phases are similar to the lattice parameters of the cubic approximant, whereas their b parameters are, respectively, three and four times larger than the c parameters. It is suggested that these phases evolve on account of local symmetry breaking of the cubic approximant phase, possibly due to ordering. [ABSTRACT FROM AUTHOR]

We report the synthesis of nanoembedded biphasic alloy particles of In–Sn near eutectic alloy compositions embedded in an aluminium matrix by rapid solidification processing. Detailed transmission electron microscopy indicates that the two phases present at room temperature in as-synthesized samples are β and γ phases with tetragonal and hexagonal crystal structures, respectively. These co-exist with a small amount of single phase In or Sn particles with sizes less than 10&ThickSpace;nm. Low temperature magnetization measurements indicate a superconducting transition temperature of 5&ThickSpace;K, suggesting complete decomposition of the β-phase at small sizes and at low temperature. The small particles show type II behavior with a critical field H c 1 ≈44&ThickSpace;G and two values for H c 2 of 250 and 1000&ThickSpace;G, respectively. These values are considerably lower than those observed in bulk In–Sn alloys. [ABSTRACT FROM AUTHOR]

The effect of size on the alloying and transformation behavior of multicomponent metallic systems has received very little attention. The present study reports a preliminary result in this direction involving Pb–In nanosized alloy particles embedded in an aluminum matrix. With the help of various techniques including in situ electron microscopy, we show that at small sizes, the Pb–In alloys particles are single-phase solid solution having fcc structure at the composition range covering both Pb and In rich regions. The results of in situ microscopy also indicate that the melting point and roughening behavior of these particles differ from particle to particle. The results are compared with that available for pure Pb particles. [ABSTRACT FROM AUTHOR]

Thin films of cubic boron nitride were deposited on silica and Si substrates by inductively coupled radio-frequency plasma chemical vapour deposition (IPCVD) technique using a B2H6&ThickSpace;+&ThickSpace;N2&ThickSpace;+&ThickSpace;Ar gas mixture. Cubic phase formation was confirmed by glancing-angle X-ray diffraction studies, which showed reflections up to (311). Fourier-transform infrared (FTIR) spectra also indicated the predominantly cubic nature of the deposited films. The optical properties of the films were studied in the wavelength range 200–1000&ThickSpace;nm. Both direct and indirect transitions were found to be present. Mechanical stress in the grain-boundary region of the films seems to contribute significantly to the optical absorption below the band gap. The intercrystalline barrier height ( E b) and the trap state density ( Q t ) were obtained from an analysis of the effects of grain boundaries on the optical properties of the samples. [ABSTRACT FROM AUTHOR]

Abstract: We report the melting behavior of nanometric-Bi particles embedded in the zinc matrix synthesized by the rapid solidification processing. These particles have specific orientation relation with the matrix given by {0001}Zn ∥{10–12}Bi and 〈11–20〉Zn nearly ∥〈1–210〉Bi. A change in melting behavior is observed on thermal cycling. The differential scanning calorimetry (DSC) results reveal that a fraction of Bi particles melts at 91–95 K below the bulk melting temperature during the second DSC-cycle. It is shown that the division of a single crystalline nano-Bi particle into several grains during solidification results in the significant reduction in melting, which can be explained by the phenomenological theory of melting. [Copyright &y& Elsevier]

The concept of P-spaces was first initiated by Gillman and Henriksen in 1954 and the property of a P-space is intrinsically related with the cofinality character w0 of the real line. In this paper, we will show that the properties of countable cofinality and Cauchy completeness determine the class of P-spaces. Also, there are indeed innumerous ordered fields that are Cauchy complete and has a countable cofinality character, and a generic method to construct them is provided in Theorem 3.9. This paper contains a cardinal extension of the easier side of Theorem 3.8 and ends with an open question. [ABSTRACT FROM AUTHOR]

Input of mechanical energy at a high rate can drive a system and induce phase transformations and chemical reactions away from equilibrium. The evolution of such a change depends on both thermodynamic as well as kinetic factors. Besides the microstructural changes like attainment of nanostructure, which alters the overall free energy, the high rate of mechanical energy input also changes the kinetics by influencing the mass transport and related processes. In order to understand these factors, we have recently started a programme of looking at the influence of mechanical energy on driving simple chemical reactions in solid state. In this presentation we shall present and discuss the results of two kinds of situation that we have studied. The first one is simple electrochemical replacement reactions between metals and metal sulphates in solid state. We show that the mechanical milling alters the kinetics of these reactions, which can be rationalized by considering the phenomena taking place at the microscopic level. For example we will show that the crystal structure of the sulphate and the nature of the reaction product at the interface influence the mechanochemistry significantly. It is even possible in some special cases to alter the direction of the chemical reaction. In the second set of results we shall present the effect of mechanical milling on the site occupancy in ferrites, which can lead to a significant change in magnetic behaviour. [ABSTRACT FROM AUTHOR]

Multilayers of Ni and Al of 1:1 ratio, 50 nm periodicity, were deposited using sputtering. Progress in phase evolution in these films upon annealing and laser mixing has been studied. Characterization of the as deposited and the treated states were carried out with X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) techniques. As-deposited state reveals the presence of elemental Ni and Al with grain size comparable to the film thickness. Phase evolution upon annealing occurs in several stages determined by the kinetics of nucleation and growth. Al3Ni and Al3Ni2 initially form at 673 K and transforms to a mixture of AlNi and Ni3Al at about 873 K. Films were also treated with nanosecond laser pulse of 20–200 mJ energy with spot size of 1 and 1.5 mm. The major phase obtained after laser irradiation is B2 with grain size increasing with increasing imparted pulse energy. In addition to B2, microtwins and tweed microstructures are often observed. The origin and the nature of twins have been analysed in details. Formation of this type of microstuctures in polycrystalline thin films and with Ni content <62 at.% has not been reported previously. [Copyright &y& Elsevier]

Nanocrystalline microstructures with a high fraction of intermetallic phases were synthesized in a series of Al based systems, Al–X–Zr (X=Si, Cu, Ni) by using rapid solidification processing. The intermetallic phases and the nano scaled grains both contribute to the very high hardness values, up to 5 GPa, for the as melt spun ternary alloys. The ternary Zr additions were found to achieve an increase in the hardness at least two times that of the corresponding binary eutectics, and nearly five times that of coarse grained Al. Several mechanisms of strengthening tend to operate simultaneously in such multiphase fine grained materials. An estimate of the different contributions to the strength via an analysis of their hardness, reveals that the strengthening due to grain refinement is the strongest mechanism. The Hall–Petch effect dominates over the Orowan strengthening by a factor of 4. However, the grain size effect is not a classical one, and is found to be substantially modified by the role played by the grain boundary precipitates. [Copyright &y& Elsevier]

Nanoscaled (In, Sn) alloy inclusions in Al matrix have been synthesized via rapid solidification processing route. Preliminary characterization of the samples has been done by X-ray diffraction. The microstructure of these alloy inclusions has been analyzed using transmission electron microscopy. Both In and Sn are immiscible with Al, and the miscibility gap can be accessed under rapid solidification conditions. In and Sn react with each other to form two intermediate phases, viz. β and γ respectively, which together form a eutectic. The morphology and orientation relationship of this β–γ eutectic system in nanoscale is reported here. TEM study reveals that majority of the alloy inclusions possess near cuboctahedral symmetry and that they are bicrystalline. Distinct two-phase contrast of these phases is observed in most cases. Melting and solidification characteristics of these alloy inclusions have been investigated via DSC. A melting peak at higher temperature is observed in the first cycle in addition to the eutectic melting event. Multiple solidification exotherms in the DSC is observed with maximum undercooling of 5 °C in the present case. [Copyright &y& Elsevier]

A large number of nonequilibrium processes for synthesizing metastable materials use mechanical energy for driving the process. The mechanical energy can also alter chemical reactions in a significant manner. In order to understand the role of mechanical energy we have initiated a program of research to explore basic processes behind the mechanical energy induced changes by designing experiments using simple systems. We show that milling leads to both the enhancement of the thermodynamic driving force and the transport kinetics. The former is achieved through reduction in length scale and possible breaking of the bonds. The defects also enhance kinetics. The relative importance of these two factors depends on the system being studied. Analysis of mechanochemical reactions using simple electrochemical replacement reactions involving ionic bonds elucidates the roles of thermodynamics and kinetics. Finally, it is shown that under certain conditions, it is possible to induce reverse reaction by mechanical milling. [Copyright &y& Elsevier]

Nanocrystalline undoped and Mn doped zinc sulphide (ZnS) thin films were synthesized by a wet chemical route without using any capping agent. The x-ray diffraction pattern showed the typical interplanar spacings corresponding to the cubic phase of ZnS. Transmission electron microscopy (TEM) studies confirmed the nanocrystalline nature with an average particle size [inline image] nm. Compositional information was obtained from the energy dispersive x-ray studies. A UV–visible optical spectroscopy study was carried out to determine the bandgap of the nanocrystalline ZnS and it showed a blue-shift with respect to the bulk value. Variation of bandgap energies with annealing temperature was also studied in detail. A photoluminescence (PL) study of the ZnS and ZnS:Mn films at room temperature (300 K) indicated a strong luminescence band at energy 2.07 eV. [ABSTRACT FROM AUTHOR]

We report the early stage friction and wear characteristics of aluminium containing nanosized lead dispersions. The nanocomposite was produced by rapid solidification. The experimental results indicate a significant decrease in friction and wear rate in comparison to its coarse grained counterparts. We show that the observed results suggest an adhesive type of wear mechanism. However, increase in hardness due to refinement of the aluminium grains cannot quantitatively rationalize the results. We explore and discuss the role of nanoscaled lead particles and the mass transport between the sample and counterface via mechanical alloying, in the formation of tribolayers affecting the tribological properties. The plane view and cross-sectional transmission electron microscopy reveals significant elongation as well as coarsening of the lead particles during the process of wear. We attempt to understand these results in the framework of moving dislocations and their assistance to the mass transport among the dispersed lead particles. [Copyright &y& Elsevier]

Cr2+:ZnSe is now known as a room-temperature widely tunable solid-state mid-infrared laser material. Optimization of laser performance requires first and foremost optimization of the Cr2+-doping level in the crystals. A simple theoretical model has been developed for evaluation of the thermal diffusivity of Cr2+ ions in bulk ZnSe single crystals and polycrystalline window materials, from optical absorption measurements in the 1200–2800 nm spectral region. Sputtered metallic chromium and powders have been used as dopant sources. Diffusion appears to be faster in polycrystalline materials than in single crystals for annealing temperatures below 910°C. The activation energy, which is lower in polycrystals, depends on the nature of the dopant source. For mid-IR laser application, the model predicts for example, non-negligible optical losses due to passive self-absorption in the 2000–3000 nm spectral region for chromium-doped polycrystalline materials after annealing at temperatures above 900°C for 1.75 days. [Copyright &y& Elsevier]

This work reports the synthesis of pure and nickel-doped graphitic carbon nitride (GCN) by simple thermal decomposition of urea at a moderate temperature (550 °C). The concentration of nickel was increased systematically to see the effect of dopant concentration. Both the pure and doped samples were characterized by techniques like X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (FESEM), UV–Vis, Fourier transformed infrared (FTIR), and Raman spectroscopy. The thermal stability of the sample was analyzed with the help of a thermal gravimetric and differential thermal analysis (TG–DTA) study. XPS confirms the successful doping, whereas both XRD and FESEM show that when pure GCN gets doped with the transition metal, the crystal structure, as well as the morphology of the sample, changes. The Kubelka–Munk plot shows the monotonic decrease of the optical band gap of the material. Photoluminescence (PL) spectra of the GCN showed quenching of the intensity when nickel was introduced. The efficacy of the as synthesized material in removing textile dyes like Rhodamine B (Rh-B) through the process of photo-catalysis (PC) which is catalytic reaction under the influence of photons of suitable wavelength has been tested. It was seen that the observed PL quenching, in contradiction to the expected result, does not support PC when attempting to remove Rh–B under UV light. The pure GCN shows the best removal efficiency, achieving approximately 100% within a time duration of 70 min. The reaction mechanism has been explained in view of the pseudo-1st-order reaction. The anomaly of the PC results was qualitatively explained in terms of the abundance of oxygen and changes in the surface area. This is the 1st report where GCN shows a simultaneous enhancement of PL and PC properties. [ABSTRACT FROM AUTHOR]

Additive Manufacturing (AM) is an emerging technology for fabrication of structural components, which refers to the processing through layer by layer addition of material using sliced CAD model of the desired geometry. Maraging steels are especially used in aerospace and tool industries due to their excellent combination of strength and fracture toughness. The present work aims at studying the effect of build orientation on microstructure and tensile behaviour of maraging steel (M300) processed by one of the AM techniques, namely, Selective Laser Melting (SLM). Initially, AM plates were processed in orientations of 0°, 45° and 90° and were further given solution treatment and aging. Measurement of density, surface roughness, hardness, residual stress and microstructural characterization of all samples were carried out and compared with those of conventionally melted (CM) samples. Transmission Electron Microscopy (TEM) confirmed the presence of Ni 3 Ti needle shaped precipitates and Fe 2 Mo globular precipitates after AM processing and also after heat treatment. Tensile testing of samples was conducted at a strain rate of 1 × 10−3 s−1. Better strength with reasonable ductility was observed in the samples built in 45° orientation compared to those at other build orientations and the properties in CM conditions. Solution treatment followed by aging decreased microstructural anisotropy caused by layer-wise effect due to laser processing. Surprisingly, most of the AM samples after heat treatment showed increase in strength without significant loss of ductility. Larger degree of work hardening and reversion of martensite to austenite might be the reasons for the observed behaviour. Typical ductile fracture featuring dimples due to microvoid coalescence were observed in all samples. Heat treatment not only improved tensile properties but also reduced anisotropy and residual stresses introduced during material processing. [ABSTRACT FROM AUTHOR]

A theoretical approach for predicting glass forming ability of transition metal alloys is proposed. This is an attempt for synergistic understanding of the effects of thermodynamics and local geometry on glass forming ability. The enthalpy of formation has been estimated by a modified Miedema’s model and used as a criterion for stability. The lattice strain energy has been estimated by a modified Miracle’s model. The coordination numbers of the solute centered clusters have been used for establishing a set of inequalities that demarcate geometrically favored composition regimes. Glass formation within the geometrically favored areas is dictated by thermodynamics. [ABSTRACT FROM AUTHOR]

Surface nanostructure was developed on the peak aged IN718 superalloy using surface mechanical attrition treatment (SMAT) and its influence was studied on low cycle fatigue (LCF) behaviour. The gauge section of LCF samples was SMATed with steel balls of 3 mm for the duration of 5 min at constant frequency of 20 kHz using StressVoyager to modify the surface. Surface grains of 36 μm were refined to ~49 to 73 nm following SMAT. Strain controlled cyclic tests were performed for the non-SMATed and SMATed samples at ±Δε t /2 from ±0.50% to ±1.0% at strain rate (ė) 1 × 10−3 s−1 under reversed loading (R = –1) at room temperature. LCF life of the SMATed specimen at Δε t /2 = ±0.50%, was enhanced by more than twice that of the non-SMATed specimen. • Surface grain of peak aged IN718 superalloy were refined to nano level (49-73 nm) by SMAT. • The grain refinement was observed up to a depth of ~200 μm from the SMATed surface. • Low cycle fatigue life was improved by two times at lower strain amplitude of ±0.50%, from SMAT. [ABSTRACT FROM AUTHOR]