Karnival Jom Sains rangsang minat sains pelajar

SERDANG – Universiti Putra Malaysia (UPM) menganjurkan Karnival Jom Sains bagi merangsang dan memupuk minat masyarakat terhadap sains, teknologi, kejuruteraan dan matematik (STEM) yang berpotensi menjamin masa depan generasi muda serta ekonomi negara

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

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

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

Study of simple pendulum using tracker video analysis and high speed camera: an interactive approach to analyze oscillatory motion

In this paper, we report on the use of Tracker video analysis and high speed camera as an interactive approach to study oscillatory motion of a simple pendulum. Tracker software is basically a computer based learning tool and is preferred because it is free, user friendly and support effective learning and teaching. Combining with the high speed camera that records the motion of pendulum at a frame rate up to 1000 frames per second (fps), analysis of the motion is performed at different angles and video qualities. The periods obtained from the experiment are then compared with the exact period expression and Lima and Arun approximation in order to determine how well this approach suited for the large angle approximation. Results have shown that when the video qualities improved, errors are minimal but errors increased when the angle increased. This research finding shows that this approach is feasible in studying the motion of simple pendulum and at the same time, interactive and inexpensive

Surface plasmon resonance optical sensor for detection of essential heavy metal ions with potential toxicity: copper, zinc and manganes.

In this work, surface plasmon resonance (SPR) spectroscopy had been studied for detection of essential heavy metal ions with potential for toxicity: copper, zinc and manganese ions (Cu2+, Zn2+ and Mn2+). The sensitivity of SPR optical sensor had been enhanced by introducing a thin crosslinked chitosan layer on a gold film. Crosslinked chitosan solution was synthesized by homogeneous reaction of medium molecular weight chitosan in aqueous acetic acid solution with glutaraldehyde as crosslinking agent. It was deposited on gold film by spin coating. From the results we found that the change in the resonance angle (Δθ) is directly proportional to the concentration of heavy metal ions solution (0.5-100 ppm). The sensitivity of this optical sensor for the studied heavy metal ions are in following order: Cu2+ > Zn2+ > Mn2+. The gold/chitosan interface in SPR technique is highly sensitive for these heavy metal ions with detection limit as low as 0.5 ppm

Analysis of Pb(II) ion sensing by crosslinked chitosan thin film using surface plasmon resonance spectroscopy

The crosslinked chitosan thin film had been studied as a sensor element of surface plasmon resonance (SPR) optical sensor. Crosslinked chitosan solution was synthesized by homogeneous reaction of medium molecular weight chitosan in aqueous acetic acid solution with glutaraldehyde as crosslinking agent. It was deposited on gold film by spin coating. Using SPR technique, the optical properties of crosslinked chitosan thin film before and after contacting with different concentration of Pb(II) ion in a range of 0.5–100 ppm had been obtained by fitting. The resonance angle shifted to lower value as the Pb(II) ion concentration increased. Changes in the resonance angle (Δθ) are directly proportional to the concentration of Pb(II) ion solution. X-ray photoelectron spectroscopy (XPS) had been employed to confirm chemical elements and their bonding of the thin film prior to adsorption, as well as chemical interactions involved between Pb(II) ion and the thin film

Photoluminescence properties of Eu3+-doped low cost zinc silicate based glass ceramics

In this paper, Zn2SiO4:xEu3+ phosphors were synthesized with different concentrations of Eu3+ ions (x = 1, 3 and 5 wt.%) by using waste bottle glasses as silicate source. The structure, morphology, and luminescent properties of the phosphors were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and photoluminescence (PL) spectroscopy. The XRD analysis revealed that addition of dopant increased the crystallinity of the samples, and then were decreased dramatically when the dopant concentration further to 5 wt.%. The FESEM images showed the samples have irregular in shapes while their emission and excitation peak of Zn2SiO4:xEu3+ phosphor was observed at 600 and 400 nm, respectively

Immobilization of tetrabutyl thiuram disulfide in chitosan thin film for sensing zinc ion using surface plasmon resonance spectroscopy

Tetrabutyl thiuram disulfide (TBTDS) immobilized in chitosan thin film has been studied as a sensor element for zinc ion, Zn2+, using surface plasmon resonance (SPR). The TBTDS-immobilized chitosan thin film, which acts as an active layer, was coated on a gold film by spin coating. Zn2+ can be detected by measuring the SPR signal when TBTDS-immobilized chitosan thin film contacts with Zn2+ in solution. The sensor produced a linear response for Zn2+ ranging from 0.1 to 1 ppm with a sensitivity of 0.0317 degrees ppm(-1). Using immobilized TBTDS as an active layer, the Zn2+ can also be selectively detected when present in mixtures of heavy metal ions