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Poly (hydroxybutyrate-co-valerate) (PHBV) was the ideal replacement for petroleum-based plastic, owing to its biocompatible, non-toxicity and naturally by bacteria. However, PHBV has high brittleness due to high crystallinity, becoming a major challenge for PHBV commercial production and limiting its use in molded products. Natural rubber (NR) and cellulose nanocrystal (CNC) created an excellent opportunity to enhance the modulus and minimize the effect of non-degradable materials utilized in the polymer matrix. This study demonstrates the formation of PHBV/NR/CNC ternary nanocomposites to obtain a commodity biomaterial with improved mechanical properties. The effects of CNC loadings (1, 3, 5 wt.%) on the mechanical properties and structure of the PHBV/NR/CNC nanocomposites were investigated. Based on the tensile test, the use of the CNC brought a more pronounced positive impact (especially 1wt.% CNC) to the PHBV/NR blend matrix, where it enhanced the tensile Young's modulus of the PHBV/NR/CNC nanocomposites. Fourier transform infrared spectroscopy (FTIR) confirmed the success of peroxide crosslinking after the melt compounding process by using a heated two-roll mill. [ABSTRACT FROM AUTHOR]

The effect of 0.4, 0.6, and 0.8 moles of potassium addition in Y123 (YBCO) without changing the stoichiometric of YBCO through the thermal treatment synthesis method was investigated. The effect on potassium concentration addition on the crystal structure, surface morphology, and superconductivity property was determined by using X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), and AC susceptometer (ACS). From the XRD result, the crystal structure of YBCO showed potassium enhanced YBCO crystal growth in the direction of (00l) plane, and the volume fraction was increased when the potassium concentration increased, yet the orthormbicity decreased. However, no orthorhombic-to-tetragonal transition occurred as the structure was preserved in all samples. SEM result showed the grain size of Y123 was larger for the sample with potassium addition up to 6.37 µm for 0.6-mole potassium addition. This improved the linking of YBCO grains by narrowing the grain boundary, thus improving the pinning loss, Tp values up to 88.48 K. The intergranular loss peaks observed became narrow with the increasing of potassium concentration for sample 0.8 mole. From ACS analysis, the transition temperature (Tc) was reduced for samples with 0.4 moles and 0.6 moles of potassium and then increased for samples with 0.8 moles. The highest Tc was obtained in 0.8 moles followed by pure Y123 with 92.52 K and 92.34 K respectively. It shows the improvement of the Tc performance due to the well-oriented grains of the samples with a higher phase of YBCO than the pure sample. [ABSTRACT FROM AUTHOR]

A comprehensive investigation on the comparison of superconducting properties, normal state properties and surface morphology analysis for YBa2Cu3O7-δ (YBCO) substitution with alkali metals (K and Ca) at Y site was conducted via the simple thermal treatment method. The superconducting properties and surface morphology of the specimens were characterized by using electrical resistance measurement, Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-Ray Spectroscopy (EDX). From XRD result, the YBa2Cu3O7-δ (Y-123) substituted with K showed orthorhombic crystal structure with secondary phase BaCuO2 beside a small amount of (Y2BaCuO5) Y-211. However, for the case Ca substituted in Y-123, the phase of Y-211 was not seen. While, the superconducting properties improved after Ca substitution in the YBCO system with higher average grains size compared to that of the pure and K substitutions specimens Thus, it's hole concentration, p posted the highest value among the three specimens with the lowest superconducting transition width, ΔTc = 8.02 K (Tc-onset = 82.12 K and Tc(R=0) = 74.10 K). This is due to the reduced oxygen content in the Cu-O chain in Ca substituted specimen, which led to the higher amount of hole concentration in the specimen. Hence, the Ca substituted specimen with better grain growth and compactness surface morphology exhibited higher p as designated better coupling among the grains with stronger Josephson junction. In the other points, that may also be due to the increment grain growth of the secondary phase of BaCuO2 that generates and introduced as effective flux pinning site and might attribute to the enhancement p or critical current density Jc. This propose ideas were confirmed by EDX result that element Ca seen in the area of the peak with 1.0 atomic % and 0.98 atomic % (cross section), while K peaks couldn't be detected. Thus, we confirmed that Ca has fully introduced within the grain without altering the structural symmetry while K was decomposed in the sintering process in the high enough sintering temperature i.e. 920 °C. Moreover, this comparative study highlights the importance of alkali metals, K and Ca substitution in the YBCO system or bulk rare earth based (REBa2Cu3Oy (RE=bulk rare earth)) high temperature superconductors synthesized using thermal treatment method. [ABSTRACT FROM AUTHOR]

Batik industry is a growing textile industry in Kelantan. Improper treatment of wastewater from manufacture units leads to water pollution. One of the most abundant and harmful pollutants found in the batik industries effluents is Rhodamine 6G. A nanomagnetic adsorbent composite (NMAC) was used in this study to remove the Rhodamine 6G from aqueous solution. In this study, Box-Behnken Design is applied to obtain a model for optimum conditions for dye removal. A maximal dye removal (99.03%) was attained with optimum conditions; initial dye concentration of 26.12 mg L−1, contact time of 14.33 min, adsorbent dose of 0.05 g, particle size of 190.26 µm and pH of 6.54. A quadratic equation was validated with 99.97 % fit between predicted and experimental outcomes. [ABSTRACT FROM AUTHOR]

Transformation from traditional mass and batch manufacturing into lean manufacturing has helped many organisations to become more successful in their business. However, there are facts and figures that show most manufacturing organisations have failed to sustain this success in the long run. One of the reason is, the lack of effective measurement criteria to assess their progress in lean transformation. The purpose of this article was to develop a valid assessment tool that measures manufacturing organisations' lean transformation sustainability level. An assessment tool in the form of survey questionnaire was developed and tested for content validity using a panel of ten experts. An item content validity index was calculated for each indicator measuring lean transformation sustainability. Items with content validity indexes greater than 0.80 were retained and item with lower content validity index were discarded. The assessment tool has evidence of content validity and will need further test using statistical techniques to determine construct validity and reliability. [ABSTRACT FROM AUTHOR]

Hydroplaning is known as one of the factors which causes the highest rate of accident occurred on wet road condition. There are many factors that causes hydroplaning to occur on the tyre. The risk for hydroplaning occurs is related to one of these factors: tyre tread depth, tyre groove spacing, tyre groove width, surface depth water and pavement texture properties. All these have the factor for hydroplaning to occur on wet road condition. Tyre groove pattern has been commonly used in the industry to design daily used tyre for commercial passenger vehicle. It helps water escape through the groove tunnel during the drive. Hydroplaning speed can be increased through increasing the tyre groove depth. The aim of this study is to identify the groove pattern which has the highest risk of hydroplaning on wet road condition with three chosen tyre groove pattern. Rib pattern, lug pattern, block pattern have different characterize driving on road. From this study we can identify which is the best tyre groove pattern to reduce the risk of hydroplaning. Solidwork is used to visualize the 30 designs of the four tyre groove pattern. All of the tyre width are set to be at constant value with 185 mm. The 30 design can be analyzed and simulated through ANSYS software with the module Computational Fluid 0ynamic (CF0). CF0 allow us to simulate visualize the process of the tyre going through hydroplaning scenario stage by stage. The test environment for the simulation is set to be 500 x 500 x 5mm. The current finding shown that larger tyre groove width and depth and smaller tyre groove spacing experience higher hydroplaning speed. When the tyre contact point is at wet road surface, it will increase the rate of the water to escape though the channel. In conclusion, block groove tyre has is the best groove tyre to prevent the risk of hydroplaning. [ABSTRACT FROM AUTHOR]

A technical assessment of pneumatic conveying of solids at various operating temperatures for a high temperature solar particle receiver is reported. The power consumption of the conveying system was determined from a calculation of the pressure drop in the conveying pipes. The enthalpy loss of the transported particles was estimated from an energy balance and the heat losses through the wall. The power consumption of the pneumatic conveying system was found to decrease significantly with an increase in conveying temperature and to be less for a dense phase conveying system that for a skip hoist conveyor, where the solid input temperature is higher than 150 ˚C. The equivalent threshold temperature is 400 ˚C for a dilute phase conveying system. Nevertheless, including the enthalpy loss of the particles caused by the increases in both mechanical energy and gas enthalpy, the dense phase conveying is more energy efficient than skip hoist if the solid input temperature is higher than 450 ˚C while the dilute phase conveying always consumes more energy than skip hoist, under the studied conditions. [ABSTRACT FROM AUTHOR]

This paper proposes a new method of recycling spent acid from local cold rolling industry into iron oxide pigment that to be applied to the roof tiles. Pickling is a process in which a hot-rolled steel that has rusty scale is dipped into hydrochloric acid prior to further processing. The waste acid contains valuable elements that can be synthesized into iron oxide pigment materials. Through neutralization between a waste acid and three different alkalis namely sodium hydroxide, potassium hydroxide and calcium hydroxide, sludge is formed and further calcined into iron oxide pigment. Colour values include L*a*b* were measured using chromameter. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that sodium hydroxide and potassium hydroxide are the suitable alkalis in this study. Calcination at 600°C produced red iron oxide pigment materials with good colour properties. [ABSTRACT FROM AUTHOR]

After years of operation, oil and gas pipelines are subjected to various damage mechanisms such as third party damage, material defect, and corrosion. These damaged pipelines need to be repaired/rehabilitated to ensure safe operation in the future. Nowadays, numerous rehabilitation techniques and repair methods are available for onshore and offshore pipelines including the usage of Fibre-Reinforced Polymer composite. A composite repair system consists of three parts which are composite wrapper, adhesive and infill materials and it is the most preferable techniques in repairing damaged pipeline in oil and gas industry. High strength infill materials has the potential in improving overall repair performance of composite repair system. The purpose of this research is to investigate the effectiveness of graphene nanoplatelets as reinforcement to enhance the mechanical properties of epoxy grout used as infill materials by adding 0.01%, 0.05% and 0.1% of graphene nanoplatelets. The dispersion was done by calendaring technique using a three-roll mill machine where the graphene particles were de-agglomerated to achieve homogenous dispersion. The results of tensile and compression tests show increment of strength for all graphene-modified samples. The strength increment was recoded range from 23% to 50% and 9% to 22% under tensile and compression test, respectively. The highest tensile strength was recorded at 20.89 MPa for sample with 0.1% graphene while sample with 0.05% graphene shows 82.67 MPa in compressive strength. This signifies the effectiveness dispersion of graphene nanoplatelets as reinforcement in the epoxy grout. As a conclusion, graphene nanoplatelets has great potential to improve the mechanical properties of epoxy grout with the aid of proper dispersion process. [ABSTRACT FROM AUTHOR]

Inorganic-organic hydrogels based on dimethacrylated polydimethylsiloxane (PDMSMA) and diacrylated poly(ethylene glycol) (PEGDA) macromers were prepared via photocrosslinking method. Silane coupling agent was incorporated into the hydrogel formulations to overcome the phase incompatibility. Pure PEGDA (0:100) hydrogels showed the highest value of ESR %, while pure PDMSMA (100:0) hydrogels showed no swelling as we expected. Inclusion of more hydrophobic domains resulted in a lower value of ESR %, i.e. in 75:25 hybrid hydrogels. Beside, we had noticed 50:50 and 75:25 hybrid hydrogels disintegrate during swelling period. However, their integrity was improved and sustained after the coupling agent was added. Similarly, the value of E* for the hybrid hydrogels showed an increment after the coupling agent was incorporated, and this is in a good agreement with the SEM micrograph which display an improved interfacial adhesion. [ABSTRACT FROM AUTHOR]

In this work, Nd0.7Ba0.3MnO3 was synthesized via cryo-milling method to investigate the effect of calcination temperature on the structure, microstructure, magnetic and electrical properties. XRD analysis revealed all samples can be indexed to orthorhombic structure systems with Imma space group accompany with some minor phases of Mn2O4 and BaMnO3. FESEM analysis confirmed that a slight increase in the grain size from 117.4 nm (600°C), 119.5 nm (700°C), 121.0 nm (800°C), 123.1 nm (900°C) to 138.4 nm (1000°C) was observed when different calcination temperature was applied. Four Point Probe measurements showed that all samples are in paramagnetic insulating region and TMIT is lower than 20K. Resistivity increase when grain size reduces due to increase of effective grain boundary that weakens the electron hopping process via double exchange mechanism. Beside, a drastic increase of resistivity also observed due to present of minor secondary phase (BaMnO3) in sample C9. [ABSTRACT FROM AUTHOR]

In this work, Nd0.7Ba0.3MnO3 was synthesized via cryo-milling method to investigate the effect of calcination temperature on the structure, microstructure, magnetic and electrical properties. XRD analysis revealed all samples can be indexed to orthorhombic structure systems with Imma space group accompany with some minor phases of Mn2O4 and BaMnO3. FESEM analysis confirmed that a slight increase in the grain size from 117.4 nm (600°C), 119.5 nm (700°C), 121.0 nm (800°C), 123.1 nm (900°C) to 138.4 nm (1000°C) was observed when different calcination temperature was applied. Four Point Probe measurements showed that all samples are in paramagnetic insulating region and TMIT is lower than 20K. Resistivity increase when grain size reduces due to increase of effective grain boundary that weakens the electron hopping process via double exchange mechanism. Beside, a drastic increase of resistivity also observed due to present of minor secondary phase (BaMnO3) in sample C9. [ABSTRACT FROM AUTHOR]

Noble fluorescence nanocomposite compound based on barium titanate nanoparticles (BTO), polystyrene (PSt), and terbium ion (Tb3+) was synthesized by a combination of surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization, Friedel-Crafts alkylation reaction and coordinate chemistry. Initially, a modification of surface of BTO was conducted by an exchange process with S-benzyl S';-trimethoxysilylpropyltrithiocarbonate to create macro-initiator for polymerization of styrene. Subsequently, aryl carboxylic acid functionalized polystyrene grafted barium titanate (BTO-g-PSt-COOH) was generated by substitution reaction between 4-(Chloromethyl) benzoic acid and PSt chains. The coordination of the nanohybrids with Tb3+ ions afforded fluorescent Tb3+ tagged aryl carboxylic acid functionalized polystyrene grafted barium titanate (BTO-g-PSt-Tb3+) complexes. Structure, morphology, and fluorescence properties of nanohybrid complexes were investigated by respective physical and spectral studies. FT-IR and SEM analyses confirmed the formation of BTO-g-PSt-Tb3+nanohybrids. Furthermore, TGA profiles demonstrated the grafting of aryl carboxylic acid functionalized polystyrene on BTO surface. Optical properties of BTO-g-PSt-Tb3+ complexes were investigated by fluorescence spectroscopy. [ABSTRACT FROM AUTHOR]

Nano-size polycrystalline La0.67Sr0.33MnO3 was synthesized via co-precipitation (LSMO-CP) and sol-gel (LSMO-SG) method. X-ray diffraction (XRD) technique revealed that all the samples were trigonal crystal structure with space group of R-3c. Rietveld refinement analysis showed that elongation of c-axis and smaller a-b plane was observed in SG sample as compared with CP sample. Micrograph shows that all samples having grain size smaller than 1 μm. Higher coercivity and lower saturation magnetization were observed for SG sample which has smaller (∼100 nm) and narrower particle size distribution as compared to CP sample. This variation was believed to be due to the dead layer and domain effect. All prepared nano-size manganites are non-single domain particles and non-superparamagnetic (ferromagnetic) behavior. [ABSTRACT FROM AUTHOR]

Magnetic nickel ferrite (NiFe2O4) nanoparticles have been synthesized via co-precipitation method by varying the metal precursors ratio. Four different precursors ratio (Fe:Ni) are varied at 40:60, 50:50, 60:40 and 80:20. The size of the nanoparticles is found to increase with increasing iron (Fe) content. In addition, the morphology of the particles are observed to change from spherical to a shape similar to a nanooctahedral particle when the Fe content in the initial precursors ratio increases. The X-ray Diffraction (XRD) patterns have proved the presence of nickel ferrite nanoparticles. The magnetic properties characterized by Vibrating Sample Magnetometer (VSM) at room temperature proved that the assynthesized nickel ferrite nanoparticles are ferromagnetic and the saturation magnetization (Ms) increases with the content of Fe in the sample. [ABSTRACT FROM AUTHOR]

Perovskite PrMnO3 (PMO) had been prepared in bulk by solid state reaction and thin films on corning glass, fused silica and MgO (100) glass substrate by pulsed laser deposition technique. SEM micrographs show that grains with size 2∼3 μm is observed in bulk PMO while thin films PMO show strongly connected grain structure with particle size that not larger than 100 nm. X-ray diffraction analysis shows that all samples are in single phase with orthorhombic crystal structure. Bulk PMO sample had lattice strain of 0.134% which is the lowest value among others. However, larger lattice strain was observed in thin film samples due to lattice mismatch between film-substrate and caused the MnO6 to deform. All samples shown paramagnetic or antiferromagnetic behavior, enhancement in magnetization value occurred for all PMO grew as film. We believe that larger lattice strain favor the grain growth of PMO towards more order phase. In summary, formation of structure and microstructure of thin film PMO depends on type of substrate used and it affect the magnetic property. [ABSTRACT FROM AUTHOR]

Polycrystalline perovskite manganite of Pr0.67Ba0.33MnO3 (PBMO) bulk ceramic samples were prepared by conventional solid-state reaction method. The structures, typical magnetic properties and magnetoresistance were studied. At lower sintering temperature (900 °C to 1100 °C), formation of PBMO phase accompany by secondary phases of BaMnO3 and Pr6O11 were observed. However, at 1200 °C, pure single phase of PBMO was obtained. PBMO compounds become denser upon the increase in sintering temperature. A reduction of secondary phases as sintering temperature increased lead to the enhancement of magnetization value. The highest room temperature %MR of 17.1% was found in sample sintered at 1200 °C in 10 kG external magnetic field. In summary, higher sintering temperature reduced multiphase formation and enhanced the magnetic and magnetoresistance properties. [ABSTRACT FROM AUTHOR]

In this study we report the effect of the sintering temperature of polycrystalline La0.67Ba0.33MnO3 (LBMO) manganites synthesized via solid state reaction method. LBMO have been sintered at 900 to 1200 °C in intervals of 100 °C. X-ray diffraction spectrum confirms that LBMO phase formation starts at 900 °C accompany by a minor second phase of BaMnO3 and fully forms into single phase of LBMO at 1200 °C. SEM images showed that, the grain size increased with sintering temperature and leading to densifications or lower porosity. The Tp was not affected by the sintering temperature. However, the electrical resistances of samples were decreased with the sintering temperature. At higher sintering temperature, due to grain growth and reduction of insulating BaMnO3 phase, the intergrain connectivity has been improved and the resistance drops. [ABSTRACT FROM AUTHOR]

Polycrystalline perovskite manganite of Pr0.67Ba0.33MnO3 (PBMO) bulk ceramic samples were prepared by conventional solid-state reaction method. The structures, typical magnetic properties and magnetoresistance were studied. At lower sintering temperature (900 °C to 1100 °C), formation of PBMO phase accompany by secondary phases of BaMnO3 and Pr6O11 were observed. However, at 1200 °C, pure single phase of PBMO was obtained. PBMO compounds become denser upon the increase in sintering temperature. A reduction of secondary phases as sintering temperature increased lead to the enhancement of magnetization value. The highest room temperature %MR of 17.1% was found in sample sintered at 1200 °C in 10 kG external magnetic field. In summary, higher sintering temperature reduced multiphase formation and enhanced the magnetic and magnetoresistance properties. [ABSTRACT FROM AUTHOR]

Nanosized magnetic particles are the subject of research interest because of their potential in high density magnetic recording. In this paper, iron cobalt (FeCo) magnetic nanoparticles are synthesized by co-precipitation and the magnetic and structural properties of the nanoparticles are investigated. The particles are formed through simultaneous reduction of Iron (III) chloride and cobalt (II) chloride in the presence of reducing agents. Growth of the particles size and shape due to various experimental conditions are investigated. Chemical synthesis has been successfully used to prepare monodispersed FeCo nanoparticles in the range of 10 to 20 nm. These nanoparticles are superparamagnetic at room temperature. The size and structure variations are analyzed by Transmission Electron Microscopy (TEM) and X-Ray Diffractions (XRD). The magnetic properties of the nanoparticles are characterised by saturation magnetization, remanent magnetization and coercivity from hysteresis loop by Vibrating Sample Magnetometer (VSM). [ABSTRACT FROM AUTHOR]

The Large Synoptic Survey Telescope (LSST) will be a large, wide-field ground-based system designed to obtain, starting in 2015, multiple images of the sky that is visible from Cerro Pachon in Northern Chile. About 90% of the observing time will be devoted to a deep-wide-fast survey mode which will observe a 20,000 deg2 region about 1000 times during the anticipated 10 years of operations (distributed over six bands, ugrizy). Each 30-second long visit will deliver 5σ depth for point sources of r∼24.5 on average. The co-added map will be about 3 magnitudes deeper, and will include 10 billion galaxies and a similar number of stars. We discuss various measurements that will be automatically performed for these 20 billion sources, and how they can be used for classification and determination of source physical and other properties. We provide a few classification examples based on SDSS data, such as color classification of stars, color-spatial proximity search for wide-angle binary stars, orbital-color classification of asteroid families, and the recognition of main Galaxy components based on the distribution of stars in the position-metallicity-kinematics space. Guided by these examples, we anticipate that two grand classification challenges for LSST will be 1) rapid and robust classification of sources detected in difference images, and 2) simultaneous treatment of diverse astrometric and photometric time series measurements for an unprecedentedly large number of objects. [ABSTRACT FROM AUTHOR]

The effect of Ba-substitution at Sr site on the structure, magnetoresistance and magnetic properties of La0.67(Sr1-xBax)0.33MnO3 samples with x = 0.00, 0.25, 0.50, 0.75 and 1.00 has been investigated. Single phase samples were obtained by a conventional solid state reaction method with rhombohedral (x = 0.00) and orthorombic (x = 1.00) structure. The grain size increases with Ba content. Low field magnetoresistance phenomenon at low temperature can be observed for all samples. However it vanishes at 300 K for x = 0.75 and 1.00. The variation of MR% value is small ranging between 16 to 18% at 100 K in an applied field of 1 T. All samples show a single magnetic transition from the ferromagnetic (FM) state to the paramagnetic (PM) state as the temperature increases. Curie temperature, Tc decrease with increasing Ba concentration. [ABSTRACT FROM AUTHOR]

This paper reports the preparation and the characterization of the (CuSe)1-xSex metal chalcogenide semiconductor compounds with different stoichiometric compositions of Se (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) in bulk form. The (CuSe)1-xSex compounds were prepared using the solid state reaction by varying the ratio of CuSe:Se in the reaction mixture. X-ray powder diffraction analysis is used to identify and measure the mass absorption coefficient of the (CuSe)1-xSex compounds to support the thermal diffusivity behaviour. The thermal diffusivity of the polycrystalline (CuSe)1-xSex compounds were measured and analyzed for the first time, using the photoflash technique. The thermal diffusivity values were determined to be in the range of 2.524 × 10-3 cm2/s to 1.125 × 10-2 cm2/s. It was found that the thermal diffusivity value tends to decrease as the parameter x increases. The relationship between the thermal diffusivity, mass absorption coefficient and density of the (CuSe)1-xSex are discussed in detail. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this study, polycrystalline of La0.8Na0.2MnO3 bulk and thin films deposited on MgO (100) and corning 7059 glass have been prepared via solid-state and pulsed laser deposition method (PLD), respectively. From the Rietveld analysis, all samples are in trigonal crystal structure with space group of R-3C (167). Bulk and thin films showed different microstructure and structure, where thin film have relatively much smaller average grain size as compare bulk sample and the lattice parameter differ when deposited in different types of substrate. Bulk exhibits a metal insulator transition temperature (Tp) at 228K. However, the Tp of thin film on MgO (100) and corning 7059 glass samples shifted to higher value of 244 K and 252 K, respectively. The resistance for film is relatively higher due to its smaller crystalline size and hence increased its magnetically disordered state at the surface of grains. Hence, structure and electric property of the film is affected by the type of substrate used. [ABSTRACT FROM AUTHOR]

Bulk polycrystalline of Pr0.67Ba0.33MnO3 (PBMO) ceramic prepared via solid-state reaction and converted into thin films on corning glass, fused silica and MgO (100) by pulsed laser deposition (PLD) technique. As compared to bulk PBMO, the unit cell in thin film PBMO experienced positive misfit due to lattice strain induced by substrate used resulting MnO6 to deform (change in Mn-O-Mn bond angle and Mn-O bond length). Bulk PBMO had large grains (∼1.5μm) as compared to thin film which are nano-sized (<100 nm). Two metal-insulator transition temperatures, TP (156 K and 190 K) were observed in bulk due to core-shell effect as proposed by Zhang et al.. In summary, variation of electrical behaviour was observed between bulk and thin film samples which believed to be due to the difference of ordering in core (body) and grain surface. [ABSTRACT FROM AUTHOR]

La0.67(Ba,Sr)0.33MnO3 were prepared via solid-state reaction method. Rietveld refinement showed that when Ba2+(1.49Å) is replaced with smaller ion, Sr2+(1.32Å), its lattice parameter, volume, bond distance and angle decreases, and also different microstructure was obtained. Transition temperature, Tp shifted to higher temperature while the resistance and magnetoresistance (MR) behaviour of samples were quite similar. This phenomenon believed to be due to the variation of spin-dependent scattering and/or spin-polarization tunneling across the grain surface/boundary. Typical polycrystalline (intrinsic and extrinsic MR) type of MR is shown for both samples. The highest % of low-field magnetoresistance (LFMR) (at 0.1T) of -11.5% and -10.2% at 80 K was given by La0.67Ba0.33MnO3 (LBMO) and La0.67Sr0.33MnO3 (LSMO) samples respectively. [ABSTRACT FROM AUTHOR]

A series of polycrystalline compounds with a nominal composition of Y(Ba1-xCax)2Cu3O7-δ (0<=x<=0.05) had been synthesized using solid state reaction method. Crystal structure of those samples was characterized by Rietveld refinement on the x-ray powder diffraction data. It was found that the structural parameters were not changed appreciably with Ca content in Y(Ba1-xCax)2Cu3O7-δ. While c-axis remained almost unchanged, both a and b axes decreased slightly leading to the decrease in orthorhombicity of Y-123 phase. The superconducting transition temperature, Tc was determined by measuring the change of electrical resistance versus temperature (50 K-300 K) using a four point probe technique. The Tc was observed to decrease gradually by Ca doping from 91 K for x = 0.00 to 88 K for x = 0.05 attributable to oxygen vacancy disorder. In addition, the superconducting transition breadth, ΔT, increased with Ca doping because of degraded crystallinity or inhomogeneity of the samples. Finally, scanning electron micrographs indicated grain growth induced by Ca doping. [ABSTRACT FROM AUTHOR]