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5 record(s) found

Thickness dependant effective radius of an optical trapping toward water-air interface

Abstract

This study aimed to determine the effect of sample thickness on optical trapping towards water-air interface. 3 µm polystyrene bead was diluted in deionised water and transferred to special test cell design to form 18, 70 and 141 µm. Bead was trapped by 975 nm laser from 20 to 220 kW/cm2 from the bottom glass-water interface towards water-air interface. The result showed that the bead is more confined with smaller effective radius in higher water thickness. ..

Article Published 2019 997 hits Available

The determination of an effective radius of an optically trapped polystyrene microbead distribution near a water air interface

Muhammad Safuan Mat Yeng@Mat Zin

Abstract

The research aimed to determine the effective radius (r*) of a trapped polystyrene microbead near a water-air interface and to develop a 3-dimensional piezostage control module for optical trapping within micrometre range. This study involved the development of a control program so called PZStage and the determination of r* near the water-air interface. PZStage was developed on the LabVIEW platform to control laser focus location in the trapping medium. A 3 µm bead was trapped in water at several heights towards the free space in a special design test cell. The temporal displacement data of the trapped bead was recorded by a quadrant photodiode (QPD) and analysed by a custom made program namely OSCal to determine r*. PZStage was well developed which enabled precise laser focus control in 20 µm range in three mutually orthogonal directions. The result showed that r* was constant at any focus height at fixed water thickness and laser power. .....

Thesis Published 2019 1672 hits Available

Optical trapping of a single chloroform microdroplet in water

Muhamad Safuan Mat Yeng

Abstract

The study aims to optically trap a single chloroform (CHCl3) microdroplet in water using optical tweezers. The study also investigates the effect of the preparation procedure by sonication on the chloroform microdroplet size and its stability in water. This microdroplet can potentially act as a carrier containing active molecules and for sensor applications in a fluid. The chloroform is sonicated in deionized water to produce a chloroform microdroplet solution. The size of the resultant microdroplets is observed under the optical microscope. The stability of the chloroform microdroplets in water was studied by monitoring the absorption spectra within a specified duration of time for 1 hour. A single chloroform microdroplet in the water is trapped using a 976 nm continuous laser beam with optical tweezers. The finding shows that the average size of the produced chloroform microdroplets does not vary significantly when the sonication time is less than 10 minutes. Furthermore, Chloroform .....

Article Published 2023 574 hits Available

Quantitative optical manipulation of a single 4-Cyano-4'-pentylbiphenyl microdroplet in water for actuating and sensing applications

Muhamad Safuan Mat Yeng@Mat Zin

Abstract

The study aims to formulate the production of 4-cyano-4’-pentylbiphenyl (5CB) microdroplets within a suitable range to be optically trapped, to optically trap a single 5CB microdroplet in water within a suitable size range, to optically micro-control the microdroplet using a circularly polarized laser, and to quantitatively determine factors affecting the optical manipulation of the microdroplet. 0.5 μL 5CB was mixed with the deionized water and sonicated to produce bipolar and radial 5CB microdroplet suspensions. The 5CB microdroplet was observed under optical microscopy and its size distribution was measured using ImageJ, while its stability was measured using UVVis spectroscopy. A linearly polarized laser beam of 976 nm wavelength was used to optically trap a single 5CB microdroplet in water at a specific laser power density. A circularly polarized laser beam was used to optically trap a single 5CB microdroplet to study its orientation control, rotatability control, an.....

Thesis Published 2024 625 hits Available

Effect of perceptual mode on the identification of expressiveness in piano performance

Chet, Yeng Loong

Abstract

The purpose of this study was to investigate whether the overall perception of the musical expressiveness of a piano performance is affected by the mode of presentation - audio, visual, or audio/visual combination - and whether or not mistakes made by the performer affect expressiveness scores. Subjects (N=90), were undergraduate music majors, randomly selected from two large state universities. A professional pianist performed an excerpt of a piece in three perceptual modes: audio only, visual only, and audio/visual combination, with and without mistakes. Subjects only saw, heard or heard and saw performances with and without mistakes and then rated each presentation for its musical expressiveness using a seven-point Likert scale. Two One- Way ANOVAs with repeated measures were used to analyze the data of audio only and audio/visual combination performances. A t-test with dependent variables was used to analyze the visual only mode. There were significant differences between the expre.....

Article Published 2013 189 hits Available

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