Optical properties and kinetic behavior of chlorine in pure water and swimming pool water using surface plasmon resonance technique

An optical sensor based on surface plasmon resonance phenomenon for detection of chlorine in pure water and swimming pool water is presented. The measurement was carried out at room temperature using Kretschmann surface plasmon resonance technique. When the air medium outside the metal film is changed to chlorine solution, the resonance angle shifted to the higher value. The shift of resonance angle (δθ) increases linearly with chlorine concentration in which the detection limit and sensor sensitivity could be quantified. In this work, the sensitivity of the detection was estimated to be 0.11°/ppm and 0.12°/ppm for Calcium Hypochlorite (G70) and Trichloroisocyanuric Acid (G90), respectively. The detection limit of this sensor is better than 0.1 ppm for chlorine samples and capable to monitor the chlorine concentration in swimming pool. We observed that the shift in the resonance angle (δθ) decreases with time due to reducing amount of chlorine in the solution. Result from real-time measurement of swimming pool water was compared with simulation result carried out in the laboratory. Both have shown that the resonance angle decreases with time due to releasing of chlorine gas to the atmosphere

Thermally induced nonlinear refraction of gold and silver polyvinvinylpyrrolidone nanofluid

The nonlinear refractive index of metal Au and Ag nano-fluids prepared by γ-radiation method was investigated by a single beam Z-scan technique. Under CW 532 nm laser excitation with power output of 40 mW, the Au and Ag nano-fluids show a large thermal-induced nonlinear refractive index. In the present work it was determined that the nonlinear refractive index for both Ag and Au nano-fluids are -4.80×10-8 cm2/W and -3.85×10-8 cm2/W respectively. The values of Δn0 for both samples were also calculated to be -2.05×10-4 and -1.64×10-4 respectively. Our measurements also confirmed that the nonlinear phenomenon was caused by the self-defocusing process making them good candidates for non linear optical devices

Thermal Diffusivity Measurement of Abrasive Paper Using Photoacoustic Technique

Measurements of thermal diffusivity of two types of abrasive papers are reported. We have chosen silicon carbide and aluminium oxide abrasive papers as our samples. Thermal diffusivity of silicon carbide abrasive paper with the grit size of 320,360,400, 600, 800, 1000, 1200, and 1500 were measured. On the other hand, only two grit size (120 and 240) of aluminium oxide abrasive papers were chosen in the present experiments. All the measurements were carried out at room temperature with the abrasive surface facing the laser beam. The effective thermal diffusivity values obtained for silicon carbide are in the range of (5.1 - 8.9) x 10-2 cm2/s, which is lower than the value of thermal diffusivity of pellet ceramic silicon carbide prepared from silicon carbide powder. For aluminium oxide abrasive papers the effective value of thermal diffusivity (0.18 cm2/s dan 0.35 cm2/s) is higher than the value reported for aluminium oxide ceramic. The surface structure of the sample was investigated using SEM with the magnification of 100X

Study the effect of volume fraction concentration and particles materials on thermal conductivity and thermal diffusivity of nanofluids.

Nanofluids, a mixture of nanoparticles and fluids, have exceptional potential to improve their effective thermal conductivity and thermal diffusivity, aluminum and aluminum oxide nanofluids with five different volume fractions of nanoparticle suspensions in different base fluids, i.e., distilled water, ethylene glycol (EG), and ethanol were prepared by mixing nanopowder and base fluids. Sonication with high-powered pulses was used to ensure the dispersion of nanoparticles in good uniformity in the base fluids. The hot wire-laser beam displacement technique was used to measure thermal conductivity and thermal diffusivity of the prepared nanofluids. The effects of the volume fraction concentration and particle materials on the thermal conductivity and thermal diffusivity of nanofluids were determined. The results showed that the thermal conductivity and thermal diffusivity increased linearly with increasing volume fraction concentration of nanoparticles in the respective base fluids. In addition, the thermal conductivity and thermal diffusivity increased faster in the Al2O3 nanofluids than in all the three base fluids

Characterization of the optical properties of heavy metal ions using surface plasmon resonance technique.

The aim of this research is to characterize the optical properties of heavy metal ions (Hg2+, Cu2+, Pb2+ and Zn2+) using surface plasmon resonance (SPR) technique. Glass cover slips, used as substrates were coated with a 50 nm gold film using sputter coater. The measurement was carried out at room temperature using Kretchmann SPR technique. When the air medium outside the gold film is changed to heavy metal ions solution, the resonance angle shifted to the higher value for all samples of heavy metal ions solution. By our developed fitting program (using Matlab software), the experimental SPR curves were fitted to obtain the refractive index of Hg2+, Cu2+, Pb2+ and Zn2+ ions solution with different concentrations. Both the real and imaginary part of refractive index of the heavy metal ions solution increased with the concentration. The results give the basic idea such that the SPR technique could be used as an alternative optical sensor for detecting heavy metal ions in solution

Utilization of chitosan-based sensor thin films for the detection of lead ion by surface plasmon resonance optical sensor

Chitosan-based sensor thin films were fabricated to detect trace amounts of lead ion using surface plasmon resonance (SPR) optical sensor. The gold surface used for SPR measure- ments was modified with chitosan and chitosan-tert- butylcalix[4]arene-tetrakis(N,N-dimethylthioacetamide) (chitosan-BCAT). Both chitosan and chitosan-BCAT layers were deposited on the gold surface by spin coating technique. The experiment has been carried out to monitor the SPR signals for lead ion with sensitive enhancement by chitosan and chitosan-BCAT layers. For both layers, the change in resonance angle (δθ) is directly proportional to the concentration of lead ion solution. The higher amounts of (δθ) were obtained for chitosan-BCAT film due to a specific binding of BCAT with lead ion. The chitosan-BCAT film enhanced the sensitivity of detection down to 0.03 ppm. Data analysis also has been done by Matlab software using Fresnel formula for multilayer system

Optical characterization of multi layer thin films using surface plasmon resonance method: from electromagnetic theory to sensor application

Surface plasmon resonance (SPR) is a quantum electromagnetic phenomenon arising from the interaction of light with free electrons at a metal-dielectric interface. SPR has emerged as a powerful optical sensor based on the sensing of the change in refractive index of a medium adjacent to the metal surface layer. In the present work, the data analysis in SPR method which involves determination of optical constants and thicknesses of multi layer thin films was investigated based on Kretschmann configuration. The SPR experimental results (reflectance versus incident angle plots) were analyzed by using Maxwell's and Fresnel's equations. The calculations involve transfer matrix method where the unknown optical parameters were obtained by fitting experimental SPR plots to calculated theoretical results. The utility of this transfer matrix has also been demonstrated for recently reported SPR experiment on sensor application

Measurement of Thermal Diffusivity, Optical Transmission and Optical Absorption Peaks of Laser Dyes R6G Doped in Poly (Methylmethacrylate) Using Photoacoustic Technique and Fibre Optics Spectrophotometer

Using the photoacoustic (PA) spectroscopic technique, we report the thermal diffusivity measurement of the Rhodamine 6G (R6G) doped at different concentrations in solid matrix poly(methylmethacrylate) (PMMA). The value of the thermal diffusivity was found increasing with dye concentration due to the increase of optical absorption of dye molecules in the polymer matrices. A uv-visible fibre optics spectrophotometer was also used to measure the optical spectrum of the samples. The result shows that the transmission cut off in a red region (500-600) nm shifted to the higher wavelength when the dye concentration increased. The maximum transmission (83%) was observed for the PMMA sample doped with the lowest concentration of dye, i.e. 3.1 x 104 mol/ l of R6G

Spektroskopi Impedans Getah Asli Terepoksida (SMR5 dan ENR25)

Kertas ini melaporkan pengukuran spektroskopi impedans getah asli terepoksida yang dilakukan dengan menggunakan spektrometer dielektrik pada suhu 303, 313, 333, 353 dan 373 K dalam julat frekuensi 10-2 ke 106 Hz. Hasil eksperimen menunjukkan bahawa frekuensi santaian atau cirian bagi Z", komponen maya impedans, bertambah dengan penambahan suhu. Model rangkaian litar setara (Re) yang dicadangkan di dalam kajian ini adalah bersetuju dengan data uji kaji yang diperoleh untuk julat frekuensi 10-2 - 106 Hz