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Validation of trap density theory in single layer organic light emitting diodes with tris(8 hydroxyquinolinato)aluminium as the emissive material / Mohd Suffian Zaini
No full textOrganic light-emitting diodes (OLEDs) rapidly evolving as the future of solid-state lighting and display application due to its numerous advantages and features. However, the efficiency, lifetime, and fabrication method still need to be improved. Even in solving efficiency issues in the device, there are many challenges to be addressed and overcome. In theory, charge transport phenomena contribute greatly towards increasing or improving the device efficiency. The magnitude of carrier mobility determines the performance of the device, as it influenced device efficiency. For organic semiconductor such as OLED, space-charge limited current (SCLC) theory was used to determine the mobility of the device. This theory is often true for a very basic structure in a simple organic semiconductor. One of the weaknesses in SCLC theory is that traps phenomena or trap density is neglected and not considered in formulating the mobility of charge carrier. In this thesis, a theoretical model for single-layer OLED that includes trap density is explained with the help of an equation. The focus of this thesis is to analyze and discussed the trap density effect in a single layer OLED. A single layer emissive OLED is fabricated for this project in order to validate the theory presented. Tris(8-hydroxyquinolinato )aluminium (Alq3) is chosen as the emissive material since it has been researched widely, and much-needed parameters can be easily obtained from previous research. The trap density value obtained at voltage 14 V when OLED A luminesces is 2.40 × 1015 cm-3. It is comparable with other results that have been reported indicating the method used is reliable. The rate of capturing process (trapping), Rn and de-trapping, Rn’ of the charge carriers on the localized state of the device are estimated. The parameters Rn and Rn' are plotted on the same graph to observe their relationship with the luminescence of the device. It can be observed that there are two significant regions in the plot, Rn > Rn’ and Rn < Rn’, and the intersection point of Rn with that of Rn’ indicate the voltage at which the device luminesces or known as the turn-on voltage of the device. Simulations are then performed by directly increasing the device trap density by two-fold to that of OLED A. The simulation has indicated that trap density has a strong influence on the Rn and Rn’ parameters. In order to verify the finding of the simulation, another device (OLED B) with a hole transport layer (HTL) of Poly(N,N’-bis-4 butylphenyl-N,N’-bisphenyl) benzidine (poly-TPD) of 40 nm thickness is fabricated by adding the HTL layer to the existing structure of that of OLED A. It has been proven in this work that OLED B, having a higher value of trap density luminesces at a much lower turn-on voltage, as has been predicted by the simulation results due to the influence of trap density to the parameters of Rn and Rn’ of the devices
The usage of Human Resources Management Information System (HRMIS) in the Malaysian Armed Forces: Empirical evidence in a military setting / Mohd Azmi Arifin
No full textThe use of information and communication technology (ICT) among individuals and organisations is growing in accordance with technology invention, innovation and consumer needs. Like other organisations, the Malaysian Armed Forces (MAF) are not left behind to adopt technology in its management and operations. In the individual context, the use of technology can enhance the performance and quality of MAF’s personnel work. However, the BADSA’s report in 2017 found that the use of HRMIS was not optimal in the MAF. Only 32.4 per cent of the 37 units that were audited had used the system. Therefore, this study aimed to investigate the factors that influence HRMIS use and its impact on MAF personnel. This study chose to use a quantitative method, starting with a preliminary study to identify initial factors that influence HRMIS use. The identified factors then have been integrated with the Information Systems Success Model (ISSM). From this integrated framework, measurement items have been developed by selecting items from previous studies. In addition, some items have been added based on FGDs and interviews results. The finalised items formed a set of questionnaires used in phase 2 of this study and were distributed to 750 HRMIS users in various MAF units. The analysis on the returned questionnaire has yielded findings which are significant factors in influencing the use of HRMIS and impact of HRMIS to MAF personnel. Findings from this study confirmed that factors influencing the use of HRMIS among MAF personnel are information quality, system quality, commander support, technical training, and ICT infrastructure. Based on these factors, this study recommends measures to improve the rate of HRMIS usage among MAF personnel. The study also found a significant positive relationship between HRMIS usage and individual benefits, thus showing the positive impact of HRMIS use on MAF personnel
The effect of corporate governance mechanisms and their interactions on earnings quality / Nasrin Azar
Get PDFCorporate governance (CG) mechanisms play an essential role in improving financial reporting quality, especially earnings quality. Due to corporate failures around the world, there has been a renewed interest in the effect of CG on earnings quality. The primary objectives of this thesis are to (1) investigate the impact of CG characteristics on earnings quality, and (2) examine whether the interactions between CG mechanisms influence earnings quality. Based on the agency and resource dependence theories, this study develops and examines ten main hypotheses (23 sub-hypotheses) to achieve these objectives. This study identifies CG mechanisms such as the board of directors, audit committee, external audit, and internal audit as well as the interaction among them. Earnings quality is measured using primary qualitative characteristics of accounting information (relevance and faithful representation of earnings) defined by FASB's/IASB's Conceptual Framework (2010). Relevance is operationalised by predictive value (PV) and confirmatory value (feedback value) (FV) of earnings. Faithful representation is defined by neutrality's concept using abnormal accrual. The analysis utilises panel data of 484 non-financial firms listed on the Malaysian Stock Exchanges for years 2007-2013. This study tests hypotheses using univariate and multivariate techniques. The appropriate regression model is Generalised Least Square (GLS). Further analyses, such as specification tests and sensitivity tests (OLS regression), are conducted. The results show that all board characteristics have a significant effect on PV and FV of earnings. However, board size has a negative association with them. All board characteristics have a significant relationship with neutrality except for board meetings frequency. However, the direction is positive for board independence and non-CEO duality. Board quality has a significant positive association with earnings quality. Audit committee independence and meetings frequency show a significant and positive influence on PV. Except for the audit committee meeting, none of the audit committee characteristics affects FV. Audit iv
committee meetings frequency and independence are significantly and positively, while audit committee size is significantly and negatively related to the neutrality of earnings. Audit committee expertise is not associated with the neutrality of earnings. Audit committee quality is positively associated with earnings quality. Internal audit experience has a significant positive impact on PV and neutrality of earnings, while there is no significant relationship between that and FV. Internal audit independence is negatively and significantly related to PV, FV, and neutrality of earnings. Internal audit quality also has no significant influence on PV and FV but has a significant negative effect on the neutrality of earnings. All external audit characteristics are positively and significantly related to PV. However, regarding FV and neutrality, there is no significant relationship between external audit size and them. External audit quality is significantly and positively related to earnings quality. Interactions between CG mechanisms have joint effects on earnings quality except for the interaction between board and internal audit quality, which follows substitution effects. This study contributes to the existing literature by using interaction among CG mechanisms and describing earnings quality based on FASB's/IASB's Conceptual Framework. The findings could be useful to users of accounting information, standard-setters, and regulators in reconsidering how the quality of monitoring mechanisms is improved and thus promote the fundamental qualitative characteristics of earnings
Hybrid non-destructive assessment for flow induced vibration piping systems using coupled fluid-structure interaction / Kong Keen Kuan
No full textPipelines and piping systems are of great importance in many industries such as water supply, petroleum and petrochemicals and nuclear power generation. They provide transport for high-velocity pressurized fluids operating under time-varying conditions. They are required to operate non-stop for a schedule of 24 hours a day, 7 days a week. Piping vibration failures have been one of the major causes of downtime, fires and explosions in industrial plant over the past 30 years. Failure of piping systems can have disastrous effects, leading to injuries and fatalities as well as to substantial cost to industry and the environment. Flow-induced vibration of the piping system is the most common causes of pipe cracking. The primary effect of flow-induced vibration is material fatigue from a large number of associated stress cycles. One of the normal ways of assessing the severity of piping vibration is to measure the associated dynamic stresses using strain gauges. However, it entails pre-determined measurement locations and depending on the complexity of the configuration, therefore this can be complicated, time-consuming, skill and experience-dependent. An alternative more objective non-destructive assessment stratagem is adopted using advanced experimental vibration analysis techniques, i.e., Operational Modal Analysis (OMA) and Operating Deflection Shape (ODS) analysis. An in-service piping system which is a highly pressurized gas transporting pipeline in an offshore platform is used as case study. An overall piping system including main pipeline and 3rd party components is investigated for problem severity identification purpose. This novel approach is complemented by Finite Element Analysis (FEA) where modal parameters such as natural frequency and mode shape extracted from OMA are used to correlate and verify the Finite Element (FE) model. Experimental based stress analysis is performed through FEA where ODS analysis result is used as initial displacement boundary condition to measure dynamic stresses. Complicated foundations involving weak joints on seams, various materials, and fracturing could be readily modelled, thus the highest stress concentration location could be identified through this method with higher accuracy. When different operating condition cases needed to be analysed and estimated, another set of experimental data have to be obtained, hence, in such situation it is time-consuming and labour intensive. The hybrid non-destructive assessment is further enhanced where the experimental based stress analysis is replaced by computational based stress analysis which utilises coupled Fluid-Structure Interaction (FSI) analysis computational mechanics. Operating parameters of the pipe, such as operating pressure, differential pressure, valve opening and flow rate are used as input for the well correlated FE model. Experimental and computational based stress analysis results in terms of vibration displacement and dynamic stress are compared. The results are in good agreement (less than 3% differences). Computational based approach is found to be more time and cost-saving where it can also be used to determine the maximum allowable operating condition for a complex piping system through examining the calculated dynamic stress of the piping system. In conclusion, the proposed hybrid non-destructive assessment is continuously enhanced in terms of time, accuracy, labour and complexity to rectify vibration-induced stress problem of in-service piping system
Improved characterization of thin bed and low-resistivity/low-contrast hydrocarbon reservoirs / Hijaz Kamal Hasnan
No full textThin-bed and low-resistivity/low-contrast (LRLC) reservoirs such tidal heterolithic
deposits contain a significant amount of the global hydrocarbon reserves. However, due
to millimetre-to-centimetre thin sandstone, forecasting hydrocarbon reserves and
production are challenging. Producing hydrocarbon economically from heterolithic
deposits in thin-bed reservoirs requires the characterisation of flow properties in thin beds
for improved hydrocarbon reserves and production estimates. Sedimentology
interpretation of the study area and reservoir in Malaysia shows that heterolithic deposits
are part of tidal bars in a shallow marine environment with a large areal extent that
suggests the substantial volume of heterolithic deposits which represent potential
hydrocarbon reserves. Conventional Well Logs and Experimental Core Analysis cannot
resolve and represent the flow properties in millimetre-to-centimetre scale sandstone
layers in heterolithic deposits, which resulted in underestimated hydrocarbon reserves
estimates. Characterisation of flow properties in thin sandstone layers is the first step in a
multiscale workflow in reservoir modelling that could improve hydrocarbon reserves
estimates in heterolithic deposits.
This thesis applied X-Ray Micro-CT Imaging and Analysis, Digital Core Analysis, gas
permeability analysis and 3D Visualisation on five mini-plugs from the sand dominated
regions of two muddy heterolithic core plugs, two laminated rock core plugs and one
sandy heterolithic core plug that represent sandstone units in the reservoir. The main
objectives are to characterise the porosity, permeability and connectivity of the thin
sandstone layers in the heterolithic samples and investigate the multi-scale impact of small-scale heterogeneities such as average grain size and carbonate laminates on
permeability.
Computed porosities of the five mini-plugs are consistent with the experimental results
that validated the computed porosity using digital core analysis. The computed
permeability of a mini plug from one heterolithic core plug is similar to the results of the
laminated sandstone mini-plugs which are benchmark reservoir sandstones. 3D
visualisation of the heterolithic core plug reveals laterally continuous thin sandstone
layers that are well connected and represent potential hidden sand pay and additional
hydrocarbon reserves in heterolithic deposits. Permeability gas probe measurements of
the surfaces of the core plugs validated the computed results of all samples. The results
verified the presence of permeable thin sandstone layers in the heterolithic core plug. Also,
3D visualisation of the sandstone core plugs reveals carbonate minerals. The carbonate
causes lower core plug permeability compared to their more homogeneous mini-plugs.
This result highlights the multi-scale effects of small-scale heterogeneities on
permeability at larger scales. Grain size analysis of all samples indicated that permeability
increases with smaller average grain sizes and is the main factor in permeability
difference between similar rock types.
To sum up, the methodology used in this thesis characterised the permeability of wellconnected
millimetre-to-centimetre scale reservoir sandstone layers in heterolithic
deposits that represent additional net sand pay and potential hydrocarbon reserves in
heterolithic deposits. Our methodology and results contribute to the first stages of a multiscale
workflow for reservoir modelling of heterolithic deposits in thin-bed LRLC
reservoirs. Our methods can incorporate the properties millimetre-to-centimetre scale
sandstone layers and other small-scale heterogeneities into reservoir models for improved
the hydrocarbon reserves and production forecasts
Performance of a new passive damper for seismic protection of structures / Khaled Ghaedi
No full textPassive energy dissipation devices have been successfully implemented in buildings around the world to reduce structural responses primarily to earthquakes, wind and other dynamic loads. Unlike active and semi-active control systems, passive systems make use of control devices that serve secondary functions. They are connected to structural members to increase structural damping without the use of external forces. The aim of this research is to introduce and investigate the performance of a new passive damper device called bar damper (BD), which is made of a number of solid bars sandwiched between two plates. The concept, placement and material properties of the device are initially presented and described. Subsequently, the test setup and loading procedures are presented and the performance of the proposed damper is assessed. For this purpose, two experimental test stages were implemented with cyclic loading applied. In the first stage, the BD was tested on its own keeping in view a number of design parameters, including the height, diameter and number of solid bars used in the design of the damper device. In the second stage, the bar damper was installed in a structural frame and experimentally tested under cyclic loading to monitor the performance of the device and frame structure equipped with the BD device. The results obtained in the first stage confirmed that the BD specimens exhibited stable hysteretic behavior with a smooth change from elastic to inelastic regime. The experiments also showed that the BD specimens were very efficient in energy dissipation and demonstrated appropriate tolerance in cumulative displacement as well as very ductile performance without significant strength or stiffness degradation. In addition to the experimental study, a finite element (FE) analysis was also done. The analysis results were compared with the experimental results and these were in good agreement. In accordance with the experimental and FE analysis outcomes, a simplified bilinear model of the BD was proposed to enhance practical use of the device. Moreover, theoretical equations of the damper device were derived based on its plastic mechanism. It is noted that the strength and ductility of the device estimated from the theoretical equations corresponded well with the results obtained from the experiments done in the first stage. It is also interesting to mention that it was possible to achieve suitable performance of the device in terms of increasing energy dissipation level, strength, stiffness and ductility either with the proposed formulas or according to the FE analysis. The results from the experiments on the test frames conducted in the second stage also proved the positive effect of the BD devices on the overall performance of the test frame where strength, stiffness, deformation capacity and energy dissipation level of the frame increased. Moreover, a FE model of the tested frames was developed for further investigation. Overall, it is believed that since the proposed damper achieved excellent performance, it can be adopted for practical use by structural designers to protect new and existing buildings and bridges
The effects of mobile-assisted problem-based language learning on speaking proficiency of Iranian language learners in the second language / Loghman Ansarian
No full textProblem-Based Language Learning (PBLL) is a cognitive and collaborative approach to language learning which has gained attention of language educators in the last two decades. Although previous researches have revealed that PBLL is a promising approach to language learning, a detailed look at the effects of mobile-assisted PBLL on linguistic features of speaking proficiency of the learners and the learners' views with regard to this approach are absent. In an attempt to shed light on this issue, a confirmatory sequence mixed-methods study in the EFL context of Iran was conducted. The effects of mobile-assisted PBLL was compared to the conventional language learning approach. The experimental group (n=37) went through mobile-assisted PBLL instruction and the control group (n=33) went through conventional instruction. The PBLL model was designed based on Hmelo Silver's (2004) model and Hung's (2006) 3C3R model. The Oxford Placement Test (OPT) was administered as a placement test, IELTS speaking test (Parts 2 and 3) was once administered as the homogeneity test-pretest and 3 times as posttests. A semi-structured interview was also conducted twice, once at the middle and the other, at the end of the treatment with the experimental group participants (n=17). The results of multivariate ANOVA (MANOVA) analysis after 26 sessions of treatment revealed that PBLL can positively affect the participants' proficiency in terms of accuracy of grammatical structures, vocabulary, spoken fluency, and pronunciation; however, in terms of task achievement, no significant effect was found. In addition to this, it was found that the participants’ views with regard to mobile-assisted PBLL are mostly positive. The learners believed that this approach provides them with more practice in the form of monologues and dialogues to deal with real-life issues, and it also reveals their weaknesses to them. Furthermore, it increases their self-confidence, provides them with opportunities to check their pronunciation with peers in class and to compare them to valid online sources, which also affects their incidental vocabulary knowledge, their listening and speaking proficiency at the same time. This study can have pedagogical implications for curriculum designers, language teachers, material developers, and language test designers
Design of personalised m-learning curriculum implementation model for diploma in hospitality management / R Moganadass Ramalingam
No full textPersonalised m-learning allows learner to create learning experience around his mobile devices by tailoring learning materials according to his demand. This could be possible by incorporating personalised m-learning into formal education to assist students to fulfil their learning needs and learning outcomes. Therefore, this study was conducted to develop a personalised m-learning curriculum implementation model for students enrolled in Food and Beverage Service course in their diploma in hospitality programme. This study employed the Design and Development Research (DDR) approach. The Needs Analysis phases is the first phase which aimed to investigate problems and justifications for developing the personalised m-learning curriculum implementation model for Food and Beverage Service course in diploma in hospitality programme at a private higher education institution in Malaysia. The instrument used for this phase was a need analysis survey questionnaire which was constructed based on Unified Theory of Acceptance and Use of Technology (UTAUT). The survey was conducted among fifty (50) students enrolled in Food and Beverage Service course to get their feedback on the current situation of their learning and what they expected from the implementation of personalised m-learning in this course. The second phase was the development phase which adopted Nominal Group Technique (NGT) and Interpretive structural modeling (ISM) techniques to develop the proposed model. There were 31 personalised m-learning elements finalised through NGT process. The outcomes of this phase was the experts' view on personalised m-learning elements and the relationship among these elements. The third phase is the evaluation phase where it focuses on the suitability of the model to support formal face-to-face classroom teaching and learning. This phase employed a modified Fuzzy Delphi Method (FDM) to analyse a five-linguistic scale evaluation survey questionnaire to get consensus views and opinions from 25 selected panel of experts. The experts' consensus for questionnaire items determined by the threshold value 'd' while defuzzification (Amax) values for the items used to determine the agreement of the experts. The findings from Phase 1 showed the need to develop personalised m-learning model whereas the outcomes from Phase 2 was the development of the model. The experts proposed that the final ISM model for personalised m-learning to be divided into three domains: Device Adaptation domain, Learner Adaptation domain and Situated Adaptation domain. Based on elements' driving power and dependence power, the personalised m-learning elements are further classified according to clusters using MICMAC analysis. These four clusters are Autonomous elements; Dependent elements; Linkage elements; and Independent elements. The findings from Phase 3 revealed that all experts consensually agreed with the evaluation's questionnaire items. This can be viewed from the triangular fuzzy number and deffuzification process which shows that all the items have met the requirements needed. Finally, the findings of the study can be used as a guideline when implementing personalised m-learning in formal teaching and learning process
Pemahaman ungkapan algebra dalam kalangan murid tingkatan dua / Azizah Hamid
No full textPemahaman tentang konsep ungkapan algebra penting bagi murid sekolah menengah kerana ia merupakan asas kepada pembelajaran matematik di peringkat menengah dan peringkat pengajian tinggi memandangkan kesukaran dalam pembelajaran algebra menjadi semakin kritikal. Kajian ini adalah untuk mengenal pasti pemahaman murid Tingkatan Dua tentang ungkapan algebra dengan berlandaskan konstruktivisme radikal. Penyelidikan ini menggunakan kajian kes sebagai reka bentuk kajian, yang membabitkan data berbentuk kualitatif. Peserta kajian membabitkan enam murid dari tiga kategori pencapaian akademik dengan menggunakan teknik persampelan bertujuan. Data kajian terkumpul melalui tiga sesi temu duga klinikal dengan menggunakan perakam video, catatan murid dan pengkaji. Data kajian dianalisis dengan menggunakan teknik analisis kualitatif yang merangkumi penyediaan data, penentuan unit makna, pengekodan, kajian rintis, pengekodan sebenar, semak semula, membuat kesimpulan dan menulis laporan. Perbincangan data bertumpu kepada tujuh aspek membabitkan gambaran mental, perwakilan, makna, hubung kait, komunikasi, penaakulan, dan penyelesaian masalah bagi ungkapan algebra. Dapatan kajian mendapati pemahaman murid dalam kajian ini tentang ungkapan algebra dibina sendiri dengan adaptasi pengalaman mereka melalui pengetahuan yang telah dipelajari dan perkara yang berada di persekitaran semasa murid
Teacher-tool relationship of Maldivian ESL teachers: A multiple case study / Aishath Wadheefa
No full textPrevious research has revealed the various ways teachers use the curriculum in classroom teaching. The way teachers use the curriculum not only impacts the effective implementation of the curriculum but, it also impacts the classroom instruction. This study intended to describe the teacher-tool relationship and the factors which shape this teacher-tool relationship. It particularly focused on ESL instruction in the context of Maldivian Key stage two teachers. Framing the study to include the unique characteristics of the island contexts, a qualitative multiple case study design informed by the interpretivist research paradigm was used in this study. Four schools across Maldives were purposefully selected for this study. Hence, the six teachers who were teaching English for grade six became the participants of this study. Data were collected through in-depth interviews, lesson observations and document reviews. Thematic analysis was used to analyse the descriptive data collected in this study. Furthermore, cross-case and within-case analysis was done to get an in-depth understanding of the similarities and differences between the teachers. The findings of the study suggested that there was a dynamic teacher-tool relationship, which varies from one teacher to another, from one lesson to another and from one activity to another activity. Various factors related to teachers, curriculum tools and the context were identified shaping the teacher-tool relationship. The specific characteristics of the island context including professional guidance available for teachers, the parents’ involvement, short-and long-term job opportunities available in the island, the school goals and the students’ second language experiences played a significant role in shaping the teacher-tool relationship in the remote and isolated islands of the Maldives