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A series of conducting polymer polypyrrole (PPy) and polypyrrole/cadmium sulfide (PPy/CdS) composites were successfully synthesized using the chemical reaction method. PPy/CdS composites were prepared with CdS concentration percentages ranging from 2 to 10%. From the X-ray diffraction (XRD) results, the XRD pattern showed evidence of conducting structure of polymer PPy and PPy/CdS composites. The spectrum clearly indicated that PPy polymer was amorphous. From the PPy/CdS composites spectrum, the six major peaks that were observed for all the samples were well known peaks that originated from CdS. From the results obtained, it shows that the conductivity of conducting polymer PPy and PPy/CdS composites at the low temperature range increased with the increase in percentage of CdS. The electrical conductivity increased from 2.85 × 10-7 to 1.66 × 10-5 S/cm in the low temperature range of 100 to 300K. While for the PPy/CdS composites, the increase of conductivity showed the same trend with the low temperature studied where the values increase from 2.11 × 10-5 to 8.74 × 10-5 S/cm. Key words: Conducting polymer, polypyrrole, polypyrrole/cadmium sulfide composites, electrical Conductivity.

In this paper, we present thermal conductivity and thermal diffusivity of chromium (Cr) nanoparticle suspended in ethylene glycol at different volume fraction concentrations of nanoparticle. All samples have been prepared using single step method. The thermal conductivity and thermal diffusivity were measured via hot wire‐laser beam deflection method. A numerical simulation of the heat conduction equation and probe beam deflection has been performed to determine the effective thermal conductivity and effective thermal diffusivity of Cr nanofluids. By fitting the experimental data to the numerical data, the thermal conductivity and thermal diffusivity of chromium (Cr)‐ethylene glycol was obtained. The results also show that the effective thermal conductivity and thermal diffusivity of nanofluids increases with the increasing of nanoparticle volume fraction concentration in base fluid.

La0.67(Ba,Sr)0.33MnO3 were prepared via solid‐state reaction method. Rietveld refinement showed that when Ba2+(1.49A) is replaced with smaller ion, Sr2+(1.32A), 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.

Systematic series of (B2O3,P2O5)‐Bi2O3‐PbO glasses have been successfully prepared by using the rapid quenching technique in which each oxide content changes for every series on the basis of its weight percentage. Their amorphous natures were confirmed earlier by the x‐ray diffraction technique. The experimental results show that the density of both glasses, determined by using the Archimedes principle, increases with the glass modifier content. This is due to the replacement of Bi2O3 and PbO in the borate and phosphate glassy networks. The molar volume for borate glass increases with the addition of bismuth and lead oxides, but a reverse trend occurs for the phosphate glass. The longitudinal and shear ultrasound velocities, determined by the MBS 8000 system, of both lead bismuth borate and phosphate glasses show a decreasing trend as more PbO and Bi2O3 are added to the glass system. The increase in PbO/Bi2O3 content was probably related to the progressive increase in the concentration of non‐bridging oxygen (NBOs). Thermal studies of the glass, using the Labsys DTA‐Setaram machine, show that the value of the glass transition temperature (Tg) is closely related to the chemical bond in the system. In lead bismuth borate glasses, the addition of more Pb2+ and Bi3+ results in a more dominant ionic bond character in the system and hence decreases Tg of the sample. However, in lead bismuth phosphate glasses, the addition of Pb2+ and Bi3+ not only failed to weaken the covalent character in P–O–P bonds, but strengthened it further, leading to an increment in the values of Tg.

A simple method is described to measure a Gaussian laser beam diameter using piezoelectric detection. Scanning the beam with a single-edge razor blade and monitoring the transmitted beam with a PZT detector, an accuracy of within 10% was obtained for the He-Ne laser beam.

This article reports on the effect of aluminum (Al) volume fraction concentration on the thermal conductivity and thermal diffusivity of Al nanoparticles suspended in water, ethylene glycol, and ethanol based fluids prepared by the one step method. The Al nanoparticles were independently produced and then mixed with a base fluid to produce the nanoparticles suspension. The thermal conductivity and thermal diffusivity of the nanofluids were measured using the hot wire-laser beam displacement technique. The thermal conductivity and thermal diffusivity were obtained by fitting the experimental data to the numerical data simulated for Al in distilled water, ethylene glycol, and ethanol. The thermal conductivity and thermal diffusivity of the nanofluids increase with an increase in the volume fraction concentration.

S.N. Ariffin , H.N. Lim , Z.A. Talib , A. Pandikumar , N.M. Huang d a Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia b Functional Device Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia c Department of Physics, Faculty of Science,Universiti PutraMalaysia, 43400, Serdang, SelangorDarul Ehsan,Malaysia d Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia

Due to an oversight, the data of the last column “Vs” in Table 1 was missing in the original version of this article [1]. [...]

The concept of surface plasmons originates from the application of Maxwell's to plasma whereby, the free electrons of a metal are treated as an electron fluid of high density (plasma). The density fluctuations occurring on the surface of such a fluid are called surface plasmons. Optical excitation of plasmons is not possible by direct impact of light on a metallic surface, so a prism coupling arrangement is needed. One possibility is to use a Kretschmann configuration [1] in which a p-polarized, collimated light beam passing through a glass prism undergoes total internal reflection (TIR) at glass-thin-metal film-dielectric interface. In this set-up plasmons are excited by (TIR) associated an evanescent wave after penetrating up to the metal-dielectric boundary. The surface plasmon resonance condition is given as

The nonlinear optical properties of a phosphate vitreous system [(ZnO)x − (MgO)30−x − (P2O5)70], where x = 8, 10, 15, 18, and 20 mol% synthesized through the melt-quenching technique have been investigated by using the Z-scan technique. In the experiment, a continuous-wave laser with a wavelength of 405 nm was utilized to determine the sign and value of the nonlinear refractive (NLR) index and the absorption coefficient with closed and opened apertures of the Z-scan setup. The NLR index was found to increase with the ZnO concentration in the glass samples by an order of 10−10 cm2centerdotW−1. The real and imaginary parts of the third-order nonlinear susceptibility were calculated by referring to the NLR index (n2) and absorption coefficient (β) of the samples. The value of the third-order nonlinear susceptibility was presented by nonlinear refractive or absorptive behavior of phosphate glasses for proper utilization in nonlinear optical devices. Based on the measurement, the positive sign of the NLR index shows a self-focusing phenomenon. The figures of merit for each sample were calculated to judge the potential of phosphate glasses for application in optical switching.

A series of ternary tellurite based glasses [(TeO2)70 (B203)30]100–x [ZnO]x glasses with different compositions of ZnO (x= 5 to 30 wt.% in steps of 5 wt.%) have been synthesized by melt quenching method. The role of ZnO to the glasses structure was studied by IR spectroscopy. FTIR spectra revealed broad, weak and strong absorption bands in the investigated range of wavenumber from 280–4000 cm−1 which associated with their corresponding bond modes of vibration and the glass structure. The indirect optical band gap and the direct optical band gap are in the range 2.08–3.12 and 1.54–2.36 eV, respectively. A decrease in the values of energy band gap Eg may come down to the reason that the non-bridging oxygen ion content increases with increasing ZnO content and shifting the band edge to lower energies. The optical band gap and Urbach energies were calculated from the absorption spectra measured between 190 and 900 nm at room temperature. The refractive index, n of the glasses change from 1.84–2.00 while the molar refractivities decrease from 13.06 to 12.00 with the increase of ZnO in mol%.

A series of hybrid multilayers of CuCo/Cu had been fabricated using RF magnetron sputtering technique. Investigation on film's surface morphology, structural and magnetoresistance properties had been carried out using atomic force microscope (AFM), X-ray diffraction (XRD) and four-point probe method. AFM image show that Cu layer consist of uniform size of particles size distribution. However, the CuCo show broad particles size distribution. XRD spectrum shows that both Cu and CuCo layers is Cu(111), Cu(200) and Cu(220) oriented with the formation of Cu(111) structure is dominant. The GMR ratio for all sample are small. The highest GMR value of -0.6% is obtained for sample with 5 layers. It is believed to be due to the formation of superparamagnetic particles in the sample that needed higher magnetic field to saturate it. The results also show that number of layer did not influence much to improve the GMR value.

In this study, mixtures of rice husk/rice husk ashes (RHA) with RB on different ratios were prepared. Dielectric permittivity ( ' e ), loss factor ( " e ) and AC conductivity ( ' σ ) were measured in the frequency range of 4 Hz to 1 MHz in ambient temperature. Results for mixture of RHA and RB indicate that a dipolar relaxation occurring between 10 3 - 10 5 Hz and the peak is depressed and shifted to lower frequency as the RB content increases in the mixture. Moreover, AC conductivity decreases as the RB content increase. This may attributed to production of natural oil content from RB. In contrast, a dielectric characteristic for RH is generally not affected by the RB contents. This study explore dielectric characteristic of mixture between RH/RHA and RB in low frequency range because lack of literature is reported on low frequency response. Additionally, the potential application of RH/RHA and RB could be explored in effort to diminish waste disposal and enhance environmental protection.