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Growth of semi-polar (11-22) GaN epitaxial layer on M-plane sapphire via MOCVD / Mohd Afiq Anuar
Get PDFIn the past few years, semi-polar (11-22) GaN has attracted much intention in the field of optoelectronics including light-emitting diodes (LEDs), laser diodes (LDs) and photodetectors. Commercially, GaN-based optoelectronic devices are grown along c-plane direction. However, c-oriented GaN-based optoelectronics suffer from piezoelectric polarization, which hinders the device performances. Conversely, semi-polar (11-22) GaN exhibits almost zero piezoelectric polarization effect. Furthermore, as the GaN wurtzite lattice is inclined approximately 58° respective to c-plane, it provides more sites for doping incorporation such as indium, silicon, aluminium, etc. Therefore, the semi-polar (11-22) GaN is presumed to be one of a promising candidate for efficient device applications. However, semi-polar GaN suffers from numerous crystal defects during the epitaxial process leading to poor crystal quality as well as surface properties. For decades, various approaches have been implemented to achieve an enhanced morphological and crystal quality of semi-polar (11-22) GaN. These approaches include the epitaxial lateral overgrowth (ELOG), surface selective growth on patterned substrates (SSG), and overgrowth on nano-rod array templates. However, such approaches require additional complex ex-situ processes with the use of dielectric materials. In addition, studies have also shown enhanced crystal qualities upon the utilization of in-situ techniques such as AlN/GaN multilayer and SiN interlayer. Nonetheless, such techniques require additional metal sources. In this study, enhanced surface morphological and crystal properties of semi-polar (11-22) gallium nitride (GaN) was successfully achieved via implementing an In-Situ Multiple Ammonia Treatment (I-SMAT) method. Utilization of an optimized flow of ammonia (2.3 SLM), surface striations of semi-polar (11-22) GaN was reduced yielding RMS roughness of 3.07 nm. Low scan sizes of the surface reveal an evolution of the atomic-sized terraces to a rather uniformly arranged distribution resulting in narrowing/shallowing of the interfacial valleys. X-ray rocking curve (XRC) analysis implies that I-SMAT would facilitate dislocation reduction through a selective-area etching process consequently enhancing the crystal quality. Conversely, excessive ammonia flux during the I-SMAT would degrade the structural and morphological properties of the semi-polar epilayer whereby the alternating thin GaN epilayer would undergo the selective-area etching to the extreme
Integrated in silico techniques for mechanism studies of antiviral and antidiabetic compounds / Diyana Mohd Isa
Get PDFDiscovery and development of drug is an iterative process that involves identification of target and leads discovery, lead optimization and pre-clinical of biological profile and is continued until the drugs are eligible to be tested in the clinical phase. Computer-aided drug design (CADD) is an efficient way to overcome the demands of cost, time consumption and drug validation. CADD utilizes in silico technique approaches such as molecular docking to understand their binding pattern and affinity with the target protein and molecular dynamic (MD) simulations to provide an atomic view of the dynamic behavior and stability of bioactive compound inside the target protein binding site in the aqueous solvent over a reasonable time scales. Thus, these computational techniques were able to accelerate and facilitate the drug discovery process in finding potential therapeutics lead. In this study, both methods were utilized to determine the key interaction that contributed to the optimal binding energy of antiviral and antidiabetic bioactive compounds. All compounds that were tested in in-vitro experiments gave a significant correlation with the computational calculation. Several residues were identified as key residues that provide significant information in improving and developing the compounds to be more potent towards the target or disease
Application development for goods management system towards waste minimization options / Wan Ahmad Nadzim
Get PDFWaste is a global concern. Increasing waste generation levels are causing the increase of waste management costs. In fact, the greatest costs of waste are measured by its impacts to the environment, society and economy. Prevention is better than cure—since all wastes come from goods, thus the best way to manage wastes is to manage goods. An application model of goods management system has been developed using GIS (Geographic Information System) and app prototyping. The primary purpose of goods management is to maximize goods and minimize waste by promoting reduction and reuse. GIS was used to perform spatial analyses on licensed goods and services providers in Kuala Lumpur in order to understand types of goods and services and their distribution patterns. Given the ubiquity of smartphones, app prototyping was carried out to design a platform to help people reduce and reuse. The prototype was designed to integrate GIS with features borrowed from shopping, reuse and how-to/product guide portals. The outcome of the model suggests goods management has many potentials for sustainable development. This makes goods management very useful not just in minimizing waste but also in improving the environment, society and economy
Kijang sebagai simbol dalam rekaan logo Bank Negara Malaysia / Mohd Helmi Mohd Isa
Get PDFThe main purpose of this research was to identify the symbol of barking deer used in the design logo of Bank Negara Malaysia from the aspects of significant and the elements of art usage that are in it. In this study, the authors selected Bank Negara Malaysia as a sample of the organizations to study the symbol of barking deer designed by the famous sculptor Abdul Wahab. This research covers aspects of understanding and significant of the barking deer and the use of elements of art. In addition, there were also interviews with academicians on the design, arts and the Malay studies to get their views and perceptions of the barking deer symbol on the logo. The result of this research is to analyze the meaning of the use of the actual barking deer symbol in the logo design
Pulsed laser generation in S+/S band using thulium fluoride fiber with saturable absorber / Siti Aisyah Reduan
Get PDFDemands on photonic applications has become highly saturated in C-band and L-band region, forcing the needs to work in S band region for the development of alternative data network and photonics technology tools to fulfill the future needs. There are only a few reports on exploiting S band fiber laser operation which mainly used depressed-cladding erbium-doped fiber (DC-EDF) as gain medium. The region covers only ~1480 nm to 1510 nm as mentioned by previous works. Other than that, there is limitation in the selection of rare-element gain medium to generate the emission in S band region. The use of thulium-fluoride fiber (TFF) as gain medium has been focusing in S band fiber laser since it allows the laser amplification that covers a shorter wavelength in S band region. Besides that, the ability of TFF to generate emission in S band region by a single up-conversion pumping which is a simpler and more cost-effective way, is seen to be the advantages compared to the other pumping scheme. The aim of this study is to investigate the generation of S+/S band fiber laser by using Thulium-Fluoride Fiber as a gain medium purposefully for photonics applications. Besides the investigation on TFF fiber laser in S band region, the gain profile will be calculated to identify the amplification of the proposed fiber laser. The tunability of the TFF laser will be studied by integrating the tunable band-pass filter (TBPF) into the cavity and precisely identifying the wavelength range that can be tuned. The accessibility of the generated laser in S band region for photonics applications will be identified. Saturable absorber (SA) is inserting into the cavity to investigate the generation of pulsed laser which are Q-switching and mode-locking, in S band region. Preparations and characterization of the SA will be done to identify the properties of the SA. The generation of dual-wavelength, Q-switched laser in the proposed experiment will be investigated by inserting an SA and Photonic crystal fiber (PCF) into the cavity. PCF is the potential optical media that will be used to study the generation of dual-wavelength laser in the proposed experiment. The studies commenced and the results obtained in this study can contribute to expanding telecommunication operation band and availability of photonics applications in shorter wavelength of S+/S band region
The study on the use of project success framework among project personnel / Joshua Suring
Get PDFProjects, programs and portfolios are essential for human endeavors since time immemorial. However, project success rates in various sectors are dismal and not up to expectations. This research aims to investigate the use of a multilevel project success framework among project personnel in various sectors to identify essential success levels and criteria and determine any weaknesses and gaps for enhancing the framework. This is a qualitative study during which a conceptual framework was developed and tested with data gathered using a questionnaire survey with open-ended questions which was distributed to project personnel based on snowball sampling. A total of 52 responses out of 500 questionnaires sent out were received, giving a response rate of 10.4%. The results found six levels and criteria of the project success continuum in addition to existence of the stakeholder and derived value continuums, several gaps in the use and weaknesses of the project success frameworks and thus the framework was enhanced by adding the input level, owner and sponsor and customer into the stakeholder continuum and operational value to the value continuum. Past researches show no agreement and consensus on a standardized and holistic project success framework, lack of empirical evidence of its relevance, completeness of its criteria and its practical utility and bifurcation between project management and project successes from the outcome and impact success levels. This research provides an enhanced multilevel project success framework with three continuums, the required empirical evidence for the framework and the integration of the bifurcated success continuum which can be used by project personnel to accomplish project success and organization performance excellence in general.
Keywords: Project success framework, Success criteria, Stakeholders, Value, Project Management
Quality management in oil and gas turnaround/shutdown projects / Ghadaffi Rosli
Get PDFThis study discusses the problem of defining quality in the oil and gas industry, to determine possible benefits of implementing quality, and to identify barriers of quality implementation in the oil and gas industry. Quality management is the process for ensuring that all project activities necessary to design, plan and implement a project are effective and efficient with respect to the purpose of the objective and its performance. Specifically in the oil and gas Turnaround Maintenance / Shut down Maintenance project, a comprehensive understanding of issues related to project quality is required. This research aims to investigate the benefit and barrier of quality management in the oil and gas industry. The main objective of this research is to determine the importance of quality management implementation in oil and gas TAM/SM projects. This research also aims to highlight the benefits of implementing the quality management to the overall project delivery. In addition, recommendations to improve the quality management implementation in Malaysia�s oil and gas industry will be made. Data for this research was conducted by sending questionnaire survey to the oil and gas industry players. From the data collected, it has been found that the client satisfaction, education, and training are the most important measure to improve quality performance. The findings show that certified quality programmes such as the ISO 9000 series are important.
Keywords: quality management; oil and gas; industry
New metal based saturable absorber for ultrashort pulse generation / Muhammad Taufiq Ahmad
Get PDFCost-efficient, robust and flexible laser systems are vital for a wide-range of applications ranging from high-precision material processing to biomedicine. This thesis aims to explore pure silver and gold based saturable absorbers (SAs) as Q-switcher and mode-locker in various fibre laser cavities. The generations of Q-switched pulses in 1-,1.55-, and 2-micron regions have been successfully demonstrated using a pure gold, which was deposited using electron beam deposition onto a PVA thin-film as SA. For instance, a stable Q-switched thulium-doped fibre laser (TDFL) operating at 1949 nm was successfully demonstrated with the gold SA. The proposed laser generates Q switched pulses with the maximum repetition rate of 21.95 kHz, the thinnest pulse width of 2.60 μs and the maximum pulse energy of 92.8 nJ. Passively Q-switched TDFL and erbium-doped fibre laser (EDFL) were also successfully demonstrated using a pure Ag thin-film, which was obtained using same technique and has 2% modulation depth. The silver-based Q-switched TDFL generates pulses at 28.33 kHz with pulse width of 4.82 μs and energy of 161.7 nJ at pump power of 498 mW. Passively Q-switched and mode locked EDFLs were also successfully achieved by utilizing D-shaped fibre deposited silver as SA. The generated Q-switched pulses exhibit maximum repetition rate of 66.74 kHz, the minimum pulse width of 6.12 μs and maximum pulse energy of 139.08 nJ which is comparable to other passively Q-switched EDFL system. The mode locked EDFL operates at 1.0 MHz repetition rate with 455 ns pulse width and pulse energy of 10.73 nJ. These findings show that pure gold and silver material have a great potential for photonic applications
Urban heat in tropicaL Kuala Lumpur: Microclimate, outdoor thermal comfort and mitigation by land-cover modification / Fong Chng Saun
Get PDFUrban heat island (UHI) is an urban warming phenomenon characterized by steep urban-rural temperature difference. Rapid land-use change in the urbanization process has introduced urban morphologies with impermeable surfaces and materials which causes higher heat retention in city centres. The emergence of urban hotspots is a growing concern due to the impact on the urban microclimate and human population. The comprehension of the multi-dimensional impact of UHI has become imperative to ensure good urban liveability especially in tropical cities where it is hot and humid annually. Hence, this study aims to explore the complex nexus of urban heat in terms of microclimate variations, human health implications and mitigation measures in Kuala Lumpur (KL), a rapidly developing tropical city. A study area with 500 m radius was chosen following standard microclimate monitoring procedure. Masjid Jamek (MJ), which is the selected study area from KL represents common urban morphology characterised with heterogeneous land cover and built types. This research is conducted in three phases in MJ. In Phase 1, continuous monitoring of the meteorological parameters is carried out at 2m height to identify urban microclimate variations near-surface level. In Phase 2, a cross-sectional approach is undertaken to identify the influence of urban heat on the outdoor thermal comfort (OTC) level and heat-related health implications. In Phase 3, a microclimate modelling and simulation approach is undertaken to explore urban heat mitigation measures in urban hotspots identified in the study area. Results from urban microclimate observation indicate the exposure of urban communities to distinctive hot and humid climate with high monthly air temperature (x̄=30.23°C, SD=3.90°C), monthly relative humidity (x̄=69.09%, SD=13.75%) and daily solar radiation (SR) (x̄=98.21 W/m2 , SD=119.74 W/m2 ). The hot-humid urban environment and predominant (43.3%) low wind activity of 0.5 to 1.5 m/s could be the reason for the thermal discomfort in the study area. Results from 1160 eligible respondents indicated more than half of the urban dwellers (n=633, 54.7%) reported thermal discomfort characterized with slight physiological heat stress (x̄=29.45°C PET, SD=2.11°C PET). Commonly reported heat-related health symptoms include heat exhaustion (n=569, 49.2%), tiredness (n=891, 77.0%), trouble relaxing (n=509, 44.0%) and being easily annoyed (n=471, 40.7%). Through Exploratory Factor Analysis, the 38 heat-related health symptoms are clustered into eight groups. Only pain (p=0.016), anxiety (p=0.022) and somatization (p=0.041) related symptoms were found to be significantly affected by UHI. Confounding factors such as gender, age group, ethnicity and duration of outdoor exposure in a day have varying influence towards the heat-related health outcomes. The Urban Microclimate Model developed through ENVI-MET for urban microclimate modelling and simulation was found to be reliable and accurate with moderate to strong (r=0.490 to 0.951) reproducibility of actual microclimate. Urban vegetation is the most effective urban heat mitigation strategy according to simulation results. A 15% increase in grass and tree coverage in the urban hotspot can result in a reduction of daily air temperature by 0.1°C and improvement in OTC level by 0.62°C PET. In conclusion, this study provided evidence of the deterioration of urban microclimate which led to a decline in OTC level and repercussions in heat-related health symptoms in a tropical city. The findings from the current study are expected to contribute to existing sustainable town planning practices in line with the vision of transforming KL into a top-tier liveable city
Investors’ reaction to fund’s performance: A study on fund flow-performance relationship in Islamic equity funds - an international evidence / Maimunah Johari
Get PDFFor many Islamic fund investors, in particular, the Muslims, the aim of their investment is not solely for financial rewards. Spiritual merits accrued through the observance of the Islamic principles brought forth another form of satisfaction. The compulsion to any investment, which involves any prohibited elements and businesses as prescribed by Shari’ah law, becomes an unidentified persuasion. These were despite theories, which expound that Islamic investment is a unique category of ethical investment invites a myriad of issues of investment inefficiencies. Investors who choose to invest with Islamic funds are considered irrational as they are ignoring the profitability and performance aspects of the investment. Attempting to investigate this puzzle, this thesis presents the empirical studies on Islamic fund investors’ reaction towards a fund’s performance through the measurement of fund flow-performance relationship of Islamic equity funds (IEFs). Three countries with different levels of Islamic financial development, namely Malaysia, Saudi Arabia and, Indonesia, were chosen. Data on the relationship between the fund flow and fund’s performance over the study period of 2007-2019 allowed the study to capture how investors react to top-performing and poor-performing funds through directing money into or out of the funds. The differences in Shari’ah screening criteria and the level of Islamic financial development across these countries provided ample ground to examine the reactions of investors under different jurisdictions and markets. Specifically, by using panel data analysis of static panel on monthly unbalanced panel data, this thesis strives to achieve four objectives. The first and second objectives aim to investigate the existent of asymmetric relation in IEFs across-countries and individual country. The third objective aims to make a comparison with the conventional equity funds (CEFs). The fourth objective aims to determine the influence of Islamic
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financial development on the sensitivity of the fund flow-performance relationship. The current study contributes to the literature by presenting several new findings. It reveals that the fund flow-performance relationship of IEFs across-countries as well as in the individual country is inconsistent with the asymmetric relationship. Instead, the results suggest that both the bottom and top performances attracted more outflows (inflows) when performances are down (up). Furthermore, when the sensitivities of fund flow to funds’ performance of IEFs were compared to the conventional counterpart, the findings found that investors of IEFs across-countries reacted to the poor-performing funds and best-performing funds in the same way as CEFs investors do. Meanwhile, in the individual country, investors of IEFs in Malaysia are more sensitive to poor-performing funds in current performance, while having either no reaction or less sensitive to poorˇperforming funds of past performance as compared to their CEFs investors. Besides, IEFs investors in Malaysia are perceived to be more sensitive to the best-performing funds' performances. For Saudi Arabia, IEFs investors are more responsive to the poorˇperforming funds and best-performing funds in past performances as compared to their CEFs investors. Whereas, IEFs investors in Indonesia are either less responsive or did not react to fund’s performances. Moreover, the current study could also conclude that both IEFs and CEFs investors respond equally to the fund’s performance. Finally, the current study further ascertains that Islamic financial system development across countries influence the IEFs investors’ decision making. Although the development of Islamic banking and Islamic funds industries across-countries does not influence investors’ sophistication, however, IEFs investors in Malaysia are found to be more sophisticated where the investors are not chasing for best-performing funds while flocking out of poor performing funds