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Musical and non-musical experiences of undergraduate music students’ mobility programme in South Korea between 2014 - 2016 / Lim Jia Yin
Get PDFNowadays, trend of international student mobility is increasing. Due by the growth of globalization international high education has been developing. There are many education institutions promote and offer the program of study abroad. This development has led to an increase of higher education research. There are substantial researchers are aiming to understand the influences, motivation, and benefits of study abroad. However, due to the increasing complexity of mobility, getting popular in contemporary period, there seem to be contradictions within their empirical data. By studying for a short term
in Korea, students are able to experience studying abroad through the lens of academic, musical, cultural, and lifestyle. This study aims to gain an insight of the international study mobility; to present the influences factors of international student mobility; to contribute to the scholastic resources for a deeper understanding of international student mobility; and to discover the achievements of the international student mobility
Development of Bragg fiber sensor for corrosion detection / Tan Cai Hui
Get PDFSteel corrosion has posed one of the major structural defects in the civil society today. Conventional methods for corrosion monitoring involve high maintenance cost and destructive methods with low accuracy. Recently, Fiber Bragg gratings (FBG) sensor with its high sensitivity in measuring strain and temperature have been widely studied and used in structural health monitoring (SHM). A non-destructive corrosion detection approach based on FBG sensors was developed and tested to monitor corrosion in this research work. The principle of FBG sensing is based on Bragg wavelength shifts that from the corrosion process that induced strain on the FBG due to mechanical expansion. The first method that had been carried out in this study was the Polydimethylsiloxane (PDMS) coated FBG; while second method was the development of new coating material with better sensitivity for corrosion detection, which was a mixture of PDMS strain sensitive materials and pH sensitive hydrogel. FBG were etched in hydrofluoric acid (HF) near to the core of 9.7 µm to enhance the FBG sensitivity before the application of a coating material. FBG sensors were embedded on the rebar specimen. This is to monitor the strain expansion caused by corrosion process. Their performances were then being monitored by observing the Bragg wavelength shift via FBGA. Generally, PDMS-hydrogel sensor better sensitivity for corrosion monitoring at 1.97 nm / mm / year followed by FBG-PDMS at 1.65 nm / mm / year, as compared to non-coated FBG at 1.21 nm / mm / year. Overall, this research work have revealed and proven that it is feasible to develop FBG sensors as a real-time non-destructive structural health monitoring system in civil engineering
Wideband and flat-gain optical amplifier with Hafnia-bismuth erbium co-doped fiber / Alabbas Ahmed Abduljabbar Al-Azzawi
Get PDFA compact optical amplifier with a flat-gain characteristic is demonstrated using hafnia bismuth-erbium co-doped fiber (HB-EDF) as the gain medium. The HB-EDF was recently fabricated using a modified chemical vapor deposition (MCVD) process in conjunction with solution doping (SD) technique. The fiber has an Erbium ions concentration of 12500 wt. ppm, which was realized due to the co-doping with Hafnium and Aluminum ions. Firstly, the proposed amplifier was investigated for both single and double-pass configurations. It is found that the 0.5m long HB-EDF is the optimum length for the C-band region. For double-pass HB-EDFA, at input signal power of -10 dBm, a flat-gain of 15.9 dB was realized with a gain ripple of less than 1.4 dB, along the 45 nm wavelength region from 1525 to 1570 nm. Within the flat-gain region, the noise figure was less than 8.1 dB. Secondly, a wideband HB-EDFA was demonstrated, utilizing two short lengths of HB-EDF to fulfill amplification in both C- and L-bands. The wideband HB-EDFA was achieved using two-stage in both series and parallel structures. It is found that both parallel and backward pumping-based series HB-EDFAs obtained flat-gain characteristics over a wideband operation wavelength. For instance, in parallel HB-EDFA using 1.72 m long HB-EDF, a flat-gain of 12.1 dB was realized with a gain ripple of less than 2 dB, along the wavelength region of 80 nm from 1525 to 1605 nm. Within the flat gain region, the noise figure values vary from 6 to 11.8 dB. Besides, in backward pumping-based series HB-EDFA using 2 m long HB-EDF, a flat-gain of 14.6 dB was realized with a gain ripple of less than 2 dB, along the wavelength region of 65 nm from 1530 to 1595 nm. Within the flat-gain region, the noise figure values vary from 6.8 to 10.2 dB. Finally, a wideband and flat-gain hybrid EDFA was investigated, by employing HB-EDF and zirconia-erbium doped fiber (Zr-EDF) as a hybrid active fiber, to improve the amplification bandwidth, flat-gain, and noise figure. In parallel hybrid EDFA, at -10 dBm input signal, a flat-gain of 15.6 dB was realized with a gain ripple of less than 1 dB, along the wideband wavelength region of 75 nm from 1525 to 1600 nm. Within the flat gain region, the noise figure values vary from 4.1 to 8.7 dB. Besides, for backward pumping-based series hybrid EDFA, at input signal level of -10 dBm, a flat-gain of 14.6 dB was realized with a gain ripple of less than 1.8 dB, along the 70 nm wavelength region from 1530 to 1600 nm. Within the-flat gain region, the noise figure values vary from 4.3 to 7.9 dB. The proposed amplifiers are successfully realized not only the functional requirements but also the economically viable, by mitigation the complexity and devices used. A broadband ASE light was also successfully demonstrated to cover both C- and L bands, using the hybrid active fibers in series and parallel structures. It is found that a broader and higher ASE spectrum can be achieved at the backward pumping-based series configuration
The synthesis of urethane acrylate resin from palm fatty acid distillate and some mechanical properties / Teo Kim Teck
Get PDFDepletion of petroleum reserves and increasing environmental concerns have stimulated the efforts to explore materials from readily available, renewable natural resources, such as carbohydrates, oils, fats and proteins. Plant oil and its fatty acids are promising renewable resources to produce environmentally friendly polymeric materials. Palm oil is a major crop in Malaysia and consequently palm fatty acid distillate (PFAD) has been an abundant by-product during the refinery process. PFAD could be a renewable raw material for industrial application. Thus, we develop new PFAD-based acrylate resins UV curable for coatings applications. The resins could be produced by two approaches. Firstly, mixtures of varying amount of PFAD, isophthalic acid, phthalic anhydride, neopentyl glycol and pentaerythritol were reacted to produce hydroxyl terminated macromers. Five macromers with 15, 25, 45, 55 and 70% of PFAD were synthesized. Each macromer was reacted with toluene diisocyanate and 2-hydroxyl ethyl acrylate to produce a UV curable urethane acrylate resin. The content of PFAD has significant influence on the final UV cured film. The urethane acrylate resins with 15–55% PFAD in the macromers, could be UV-cured to form hard films with a Tg of 35–62°C. These resins have potential application for wood coatings. However, urethane acrylate resin with 70% PFAD, cured to form a soft film with Tg < 30°C and not useful for coating application. In particular, at around 45% PFAD, the resin could be UV-cured in 60 s to film that has achieved pendulum hardness of 107 s and Tg of 54C. In the second approach, the influence of different polybasic acids in PFAD-based urethane acrylate resin synthesis was studied. A series of PFAD urethane acrylate resins were synthesized, fixing the PFAD at 45%, and using isophthalic acid (IPA), terephthalic acid (TPA), phthalic anhydride (PA) and adipic acid (AA) as polybasic acid building block. All macromers were formulated with same hydroxyl value at 91 mgKOH/g and polybasic acid equivalent of 0.32 g/mol in 100 g of resin. The results showed that the different structure of polybasic acid has affected the performance of urethane acrylate resin. Generally, aromatic type of polybasic acid can produce higher Tg and hardness of UV cured film. Outstanding mechanical and physical properties such as adhesion, solvent, water, corrosion resistant can be achieved by using aromatic diacids in metal coating application. To a certain extent, good weathering resistance can be achieved on metal coating. Aliphatic type of diacid could impart good flexibility and soft film formation on the PFAD urethane acrylate UV cured film
Investigation of inflammatory responses following the use of novel anisotropic hydrogel tissue expander in the skin of maxillofacial region / Kholoud Mohamed Ali Salim Igdayir
Get PDFBackground: The purpose of tissue expander is to grow healthy supplementary tissue
under the controlled of mechanical force exerted by the tissue expander. In the field of
reconstructive and plastic surgery, the use of soft tissue expanders are important for
growing healthy supplementary tissue. However, the molecular mechanism associated
with the inflammatory response associated with the force generated from the use of
tissue expanders is still not characterized. Among the many types of tissue expanders,
anisotropic type of hydrogel tissue expander was chosen due to its ability to produce
controlled incremental inflation on the tissue that enhance cellular adaptation and the
ability of the cells to resist mechanical injury. Objective: To determine whether
anisotropic hydrogel tissue expander promotes subclinical inflammatory response by
triggering the secretion of pro-inflammatory cytokines. Material and Methods: Seven, 8
weeks old Sprague Dawley rats (300g ± 50g) were used as models. The rats were
randomly divided into two groups: control group (n=3) and expanded group (n=4). The
expanders were implanted subcutaneously at the forehead region for 28 days and
surgically removed. The rats were sacrificed and skin samples were harvested and
stored in 10% formaldehyde, fixed in formalin, and embedded in paraffin wax for
histological investigation. Hematoxylin and eosin staining was performed to detect
histological changes between the two groups and to detect the presence of an
inflammatory response in the expanded samples. Moreover, the expression level of proinflammatory cytokines IL-1, TNF-α, IL-8, and IL-6 were determined by
immunohistochemistry. Immune positivity was detected using secondary antibody
conjugated with horseradish peroxidase (HRP) after staining with diaminobenzidine
tetrahydrochloride (DAB). Results: Histological analysis showed no inflammatory
response was present in the expanded tissue. There was no significant difference in
cytokine production level between the expanded and control samples (p =0.071).
iv
However, there was very strong expression of IL-1 in the expanded tissue as 83 % of
the cells were immune-positive compared to the controls. In contrast, there was no
significant difference in IL-6, IL-8, and TNF-α production. A negative non-significant
correlation between IL-1 immune-positive cells and the inflammatory cells in the
expanded tissue was observed with a Spearman’s correlation coefficient of r= -0.500,
p=0.667. Conclusion: The in vivo experiment revealed a high biocompatibility of the
anisotropic self-inflating hydrogel tissue expander and no significant immunological or
inflammatory reaction were observed between the control and tissue expanded groups
Water-soluble graphene in agar gel as electrolyte for magnesium-air battery / Liew Siaw Ying
Get PDFPresently, ever-increasing demands on energy and the global environmental issues have given the impetus to investigate the new battery systems which are inexpensive, efficient, having high performance, and also green to the environment. Among all the battery technologies, magnesium-air (Mg-air) battery is an attractive battery to be developed owing to the interesting properties of the Mg anode. Mg has high specific energy (6.46 kWh kg-1) and reactivity, apart from its high abundance, lower cost, low toxicity, and comparatively safe to handle in the atmosphere. Nevertheless, Mg-air battery is still not being widely investigated as compared to the other batteries. Electrolyte is one of the vital components in Mg-air battery. Mg corrodes readily in conventional aqueous electrolytes, resulting in battery self-discharge. Moreover, the aqueous electrolytes used may leak and evaporate through the open cell structure. Therefore, a gel polymer electrolyte with the corrosion inhibition property could be a new electrolyte material for Mg-air battery. Water-soluble graphene (WSG) was successfully synthesised through simplified Hummers’ method followed by chemical reduction (with the addition of ammonia, NH3). WSG was incorporated into agar (a natural polymer) as an environment-friendly gel polymer electrolyte for Mg-air battery. Continuous efforts have been focused on the improvement in electrochemical performance of Mg-air battery via the preparation of different WSG-AGAR gel electrolytes. Detailed investigations on different parameters, for instance, synthesis condition of WSG, agar concentration, WSG concentration, and types of electrolyte were conducted in order to produce the optimal WSG-AGAR gel electrolyte. It was found that the incorporation of 0.1% w/v WSG-7 in 3.5% w/v sodium chloride (NaCl), entrapped in 3% w/v agar gel exhibited the greatest electrochemical performance due to the optimisation between high ionic conductivity and sufficient anodic corrosion resistance. The optimal gel electrolyte had an ionic conductivity of 9.40 × 10-2 S cm-1. The discharge capacity and energy density of assembled Mg-air battery with respect to the mass of Mg anode consumed during discharging can reach up to 1303.94 mAh g-1 and 1820.70 mWh g-1, respectively, at the constant current density of 11.11 mA cm-2. The incorporation of WSG-7 (optimal WSG) in agar gel electrolyte had demonstrated the improvement in ionic conductivity by 32.96% and discharge capacity by 58.34% as compared to that without electrolyte additive. The Mg-air battery with the optimal WSG-AGAR gel electrolyte was further discharged at different current densities. The peak discharge capacity and energy density with respect to the mass of Mg anode consumed during discharging were achieved at the current density of 1.11 mA cm-2, with the value of 1632.74 mAh g-1 and 2432.78 mWh g-1, respectively. The performance of the assembled Mg-air battery with this economical, inherently safe, and environmentally benign biopolymer electrolyte was notable
Simulation and optimal control of crude oil separation process at offshore facilities to improve efficiency of oil and condensate recovery / Chin Yee Kai
Get PDFCrude oil separation process is the most crucial process in offshore production facilities in ensuring the well fluid is separated efficiently and persistently. Waxy crude or sluggish feed stream is the major disturbance that could cause operational issues and production loss due to process upset. The main objective of this research is to model offshore crude oil separation process and introduce state space control to optimize the control of total liquid and water level within the permissible range as well as to evaluate the effect of disturbances to the controls. This work presents two different modelling methods in developing three-phase separator model and application of state space control in optimizing the level control. The three-phase separator model is developed for liquid level and water phase level control using mathematical modelling and data driven modelling method via HYSYS. The mathematical model is based on two dynamic state equations representing the levels of the liquid and water and gas pressure with inflow and outflow dynamics. HYSS is used to simulate the three-separator dynamic process in a more realistic environment. The dynamic responses of liquid and water level to the command input of respective control valves are used to obtain data that is required to develop state space model. Application of state space (modern) control which are the feedback, feedforward control and integral action is investigated and evaluated in terms of its performance in controlling outflows of the separator in optimizing control of the separation process as well as in rejecting various disturbances such as slugging. In the end of this research, the simulation results show that state space control is able to control the crude oil separation process as desired while rejecting disturbances without causing process upsets. It was also found that by implementing integral action control, fast response time and zero steady state error can be achieved indicating that in the meantime, process fluctuation can be minimized and system response faster whereby it would help to improve the overall separation process efficiency
Preventing delayed cracks in SUS304 deep drawn cups using extreme blank holding forces aided by nanolubrication / Muhammad Shafiq Ibrahim
Get PDFThis study was to investigate the formation and reformation of delayed cracks of SUS304 cylindrical drawn cups under elevated blank holding force (BHF) from 8~32 kN with 1~3 wt% SiO2 nanolubricants concentrations. The widest crack-free BHF range i.e. from 29 ~ 31 kN was determined for 2 wt% of SiO2 in the experiment. Delayed cracks were also observed below and beyond this BHF range. There was an increment of frictional force at the cup flange region when entering the crack-free BHF range, as proven by the rebound in sidewall thickness, relative intensity of α′-martensite, elongated height and drawing force beyond 28 kN. The crack reformation after exiting crack-free BHF range was due to the worsened nanolubricant tribological performance when undergoing excessive pressure, hence, allowing high friction induction. The α’–martensite had the highest relative intensity (%) at 93.7 % for BHF = 28 kN, leading to the delayed cracks. The relative intensity slightly decreased after the peak within the crack-free range with intensities ranging from 83.8 ~ 89.9 % before experiencing a sharp decrease to 50.7 % for 32 kN leading to the reformation of the cracks again. Residual stresses were developed along the outer surface of the cup due to the unbending of the material when the material left the draw die profile, hence, the increase in frictional force in the radial direction along the flange surfaces reduced the circumferential tensile residual stress of the cup, particularly at 80 % cup height. The elimination of the cracks was attributed to the decrease in intensity of the α’-martensite and the lower tensile stress gradient. The minimum BHF required for eliminating the cracks was hardly altered by the increase in concentration of SiO2
Kinetic study of in-pipe water flow for power generation / Venuthan Surendaran
Get PDFIn-pipe turbine generator has a potential to harvest energy from an existing water flow from distribution pipe which have natural and pumping capacity. That flow will be used to convert kinetic energy from the pipe to rotate the turbine. In turn, the turbine may be connected to a generator to produce electric power. The fact that the in-pipe turbine generator will be a useful energy harvesting tool with potential with industrial application is recommended by many scholars. However, there is a concern where there are many types and sizes of pipe that is readily used in the water works industry. Since that concern arises a kinetic study is required to analyze and observe the flow, velocity, and kinetic energy present in different pipes. A kinetic study of pipe water flow will further enhance and familiarize industry players with the in-pipe turbine generator. The reason is that a kinetic study will give more information to turbine manufacturer to size turbine accordingly based on flow data which is available. Observing the simulation results obtained from various pipe dimensions there is a trend that kinetic energy is observed maximum at a reduced diametrical point of the pipe rather than at the pipe’s maximum diameter. When sizing turbine proper attention must be given details such as maximum velocity at various diameter to be able to maximize rate of energy harvesting. A turbine cannot be sized to be the same size as the pipe diameter as it will not be able to harvest energy at an optimum rate. This study focusses on geometry of different pipe sizes to evaluate the flow, velocity, and kinetic energy. The results obtained from this study is hoped to aid in proper sizing of turbine for industrial level applicatio
Conjugacy separability and cyclic conjugacy separability of certain HNN extensions, generalised free products and tree products / Lim Hui Min
Get PDFIn this thesis, we study two interrelated strong residually finite properties of groups, namely conjugacy separability and cyclic conjugacy separability. We extend them to certain HNN extensions, generalized free products and tree products where the associated subgroups and amalgamated subgroups are not necessarily cyclic. In the first part of the thesis, we consider HNN extensions. We begin by establishing two criteria, one for conjugacy separability and another for cyclic conjugacy separability. Using these two criteria we establish conditions for HNN extensions where the associated subgroups are central or they are a finite extension of a central subgroup or cyclic to be conjugacy separable and cyclic conjugacy separable. In the second part of the thesis, we consider generalized free products and tree products. We shall consider only cyclic conjugacy separability as results on conjugacy separability are already known. Again we begin by establishing a criterion for cyclic conjugacy separability. We then prove that certain generalized free products and tree products where the amalgamated subgroups are central or they are a finite extension of a central subgroup or cyclic are again cyclic conjugacy separable