Novel Single Phase Dc-Ac Inverter Topology With Enhanced Power Quality

Inverters are widely employed in many application such as photovoltaic (PV), uninterruptable power supply (UPS) etc for the conversion of direct current (DC) power to alternating current (AC) power. The key challenges in design and implementation of inverters are the realization of higher efficiency and good quality output power. To achieve these, this thesis presents a novel single phase DC-AC inverter topology with enhanced power quality. In this topology, a switch is connected at the lower arm of the full-bridge switches to control the output voltage across the full-bridge inverter. The switch at the lower arm of the full-bridge controls the output of full-bridge inverter by increasing or reducing the voltage level at the lower arm of the bridge. This switch of lower arm is controlled by a high frequency sinusoidal pulse width modulation (SPWM) switching signal. While the power switches of full-bridge inverter operate with square wave switching signal at a frequency of 50 Hz. The proposed topology produces a clean sinusoidal output waveform with low distortion and with minimum switching losses, thus yielding high quality output at high efficiency. Next, a random switching hybrid pulse width modulation (HPWM) inverter is developed in order to give a comparison between the proposed inverter and the random switching HPWM inverter. Both computer simulation and experiment were carried out to verify the performance of proposed topology. From the presented results, it is shown that proposed topology has superior performance compared to its conventional counterpart

Professional Learning Community in Secondary Schools Community in Malaysia

This paper outlines a research towards an initial assessment of the stage of the PLC in secondary schools in Malaysians secondary school with teachers as the main focus. A brief philosophy of the importance of learning organization and its development in various countries was reviewed and incorporated by the current situations, leading to the objectives and methodology for this study. The result showed the teachers can be active in their learning and improving their schools as to enhance the learning performance of the students in the first four characteristic dimensions refer to the practice of shared values, goals, mission and vision among teachers which play an important role in shaping the PLC in secondary school

USE OF SCENARIO PLANNING APPROACH TO EXPLORE HIGH-DENSE, MIXED-USE FUNCTION DISTRIBUTION: A CASE OF FINANCIAL VIABILITY, DAYLIGHT AVAILABILITY, AND SOLAR ENVELOPE RADIATION.

Master'sMASTER OF ARTS (ARCHITECTURE

PENGUJIAN BLACK BOX PADA WEBSITE PENDAFTARAN SISWA BARU DENGAN METODE GRAPH BASED TESTING

Sebuah sistem yang telah dibangun,  akan  melalui  tahapan  pengujian,  tahapan  pengujian  yang  dilakukan  menggunakan pengujian Black Box. Pengujian Black box merupakan pengujian perangkat lunak dimana yang diuji hanyalah fungsionalitasnya saja tanpa perlu menguji kode program atau pun desain dari perangkat lunak tersebut dan tanpa pengetahuan detil struktur internal dari sistem atau komponen yang dites. Pada awal tahun ajaran baru sekolah-sekolah melakukan pembukaan pendaftaran bagi calon siswa siswi secara serentak. Pendaftaran sekolah yang dilakukan pada saat ini sudah secara online. Pendaftaran secara online dilakukan melalui website yang dinilai lebih efektif dan efisien. Untuk mengetahui apakah aplikasi efektif dan efisien maka diperlukan pengujian terhadap system aplikasi website pendaftaran tersebut, yang mana untuk mengetahui apakah system tersebut berjalan sesuai dengan yang diharapkan atau tidak. Kata Kunci: Pengujian, Software, Black Box, Graph Based, Websit

Attitudes and motivation toward learning the English language among students from Islamic education system background: exploring the views of teachers

According to [1], motivation is one of the main determinants of second language (L2) or foreign language performance. Research in the field of attitudes and motivation has increasingly investigated the nature and role of motivation in L2 learning process, and many are inspired by Canadian psychologists, Robert Gardner and Wallace Lambert [1]. However, in Malaysia, there has been only a meagre number of researches that investigate teachers' perceptions on attitudes and motivation of students from religious school background. It is of great significance to explore the attitudes and motivation of these groups of students because the students appeared to be weak in the English language and they also held negative perceptions toward the language [2, 3]. The present study is needed to attain authentic information about possible connections between teachers' personal experiences, their perspectives and their practices regarding teaching and learning of students from the aforementioned background. This qualitative research study contains in-depth teacher interviews that document their personal perceptions, ways of dealing with students in the specified setting, and their suggestions on improving the attitudes and motivation of learning English for students from religious school background. Findings are presented according to the research questions intended for the study and several conclusions were drawn from the data. Keywords: Attitudes and motivation, English as a Second Language, Religious school backgroun

CFD simulation study of multistage vertical axis wind turbine (VAWT)

Nowadays, the generation of energy from wind power has grown significantly as one of the most important renewable energy sources in the world today. In this study, the performance of a multistage vertical axis wind turbine (VAWT) has been assessed through 3D computational fluid dynamics (CFD) simulation approach based on K-omega shear stress transport (SST) models using the ANSYS Software. The inexpensive, omnidirectional, compact and easy to assemble Savonius rotor has been applied in this study along with the multistage-rotor concept. Multistage-rotor is where one stage of the rotor is placed on top of another stage of the rotor. The wind speed tested ranges from 5 m/s to 11 m/s at a tip-speed ratio (TSR) ranging from 0.2 to 1.0. The findings for torque and power with different operating wind speed demonstrated that as the wind speed increases at constant tip-speed ratio (TSR), the torque also increases; meanwhile, the torque coefficient decreases. However, when the wind speed increases along with the increasing TSR, the power generated increases. Meanwhile, the performance power coefficient has a directly proportional relationship with the TSR and an inverse relation with the wind speed tested

Simulation study on the performance of a counter-rotating savonius vertical axis wind turbine

Wind power is an energy source that is becoming an alternative to burning fossil fuels that may harm the environment during operations due to the emission of harmful gases. In this study, simulation and performance investigations of a counter-rotating vertical axis wind turbine (VAWT) based on the Savonius S-type rotor have been analysed through a computational simulation approach. The foremost motive of this study is to widen the operating wind speed range of the counter-rotating concept in a VAWT while enhancing the conversion efficiency of a single-rotor VAWT system. The 3D simulations were performed based on the K-omega shear stress transport (SST) turbulence model. The results have shown that the counter-rotating model possesses better performance characteristics in terms of torque, power and their corresponding coefficients compared to a single-rotor design of a wind turbine. A maximum output of more than two times was obtained from the new CRWT system compared to that of a single-rotor wind turbine (SRWT). Moreover, the output of the top rotor was higher than the bottom rotor due to the increased higher rotational speed of the top rotor

Masalah disiplin murid Islam: strategi dan penyelesaian terhadap kurikulum Pendidikan Islam

Kajian ini dilaksanakan untuk mengenal pasti jangkaan masa depan mengenai masalah disiplin murid Islam dalam aspek amalan beragama dan strategi penyelesaian dalam aspek proses pengajaran dan pembelajaran kurikulum Pendidikan Islam. Untuk menjawab objektif tersebut, data dikutip menggunakan kajian Delphi sebanyak tiga sesi pusingan. Peserta kajian adalah dalam kalangan sepuluh orang pakar dalam bidang kepimpinan sekolah. Pada sesi pusingan pertama, data dikutip menggunakan kaedah temu bual. Dapatan temu bual tersebut telah membentuk item soal selidik bagi kegunaan Delphi sesi pusingan kedua dan ketiga. Data temu bual dianalisis menggunakan pendekatan tematik. Manakala, data soal selidik menggunakan kaedah statistik deskriptif iaitu median dan Julat Antara Kuartil (JAK). Kajian ini memperoleh tahap kesepakatan pakar yang tinggi untuk menyetujui setiap item apabila skor median melebihi 4 dan JAK kurang daripada 1. Dapatan kajian menemui jangkaan masalah disiplin murid Islam dalam aspek amalan beragama dengan bilangan tema dan subtema seperti berikut iaitu akhlak sebanyak 3 item, amalan membaca al-Quran (3 item), amalan solat (3 item), kesedaran terhadap hukum hakam (5 item), aktiviti bersosial (3 item) dan penggunaan bahan tegahan (3 item). Manakala, jangkaan strategi penyelesaian kepada masalah disiplin murid Islam dalam aspek pengajaran dan pembelajaran kurikulum Pendidikan Islam dengan bilangan tema dan subtema seperti berikut iaitu akhlak sebanyak 7 item, amalan membaca al-Quran (6 item), amalan solat (5 item), kefahaman terhadap hukum hakam (5 item), aktiviti bersosial (3 item) dan penggunaan bahan tegahan (4 item). Implikasi kajian ini adalah perlunya mengambil kira pandangan individu bergelar pakar dalam bidang tertentu dalam proses pembuatan keputusan

Socio-religious harmony index instrument indicators for Malaysia

The subject of inter-religious relationship among different religious adherents is crucial in determining social peace and harmony in a multi religious country like Malaysia. The question to what extend the society is susceptible to religious issues remains uncertain. This study will contribute in understanding the Malaysian socio-religious harmony status among the multi-religious adherents through development of the social religious index. To suffice part of this effort, the aim of this study was to develop the socio-religious harmony index instrument which is viable to measure socio-religious harmony level in Malaysia. However, the development of a reliable and valid instrument relies heavily on the quality of the variables or the indicators to be used to measure the index. Hence, the instrument was developed using key informants’ input via experts’ panelist which included selected stakeholders from various backgrounds such as academics, ministry officers, policy makers, non-government organization members, and head or representative of religious groups. To effectively manage the input from the expert panelists, the study adopted Fuzzy Delphi Method (FDM) as main methodology to determine the indicators and sub-indicators (quantitative indicators) to be included in the index instrument questionnaires. Fuzzy Delphi was conducted in two rounds: FDM round 1 to determine the main indicators and FDM 2 to determine the sub-indicators to measure each main indicators. Based on the experts’ consensus, the findings of FDM 1 proposed 22 socio-religious harmony indicators. For FDM 2, based on the indicators, the experts proposed 53 sub-indicators as quantitative indicators to measure each indicators. These indicators and their respective sub-indicators will be used to form the index instrument