13474 research outputs found
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Integration of polypyrrole with metal complexes of 2,6-pyridinedicarboxylic acid and their electrochemical studies as potential electrode material in supercapacitor application / Sadia Tanzim
No full textIn this study, four transition metal complexes of PDC namely: AgPDC, CdPDC, CuPDC and ZnPDC were synthesized, characterized and integrated with polypyrrole (PPY) to create four new composite materials: PPY-AgPDC, PPY-CdPDC, PPY-CuPDC and PPY-ZnPDC for studying their electrochemical performance. PPY and the composites were synthesized using two techniques: in-situ oxidative polymerization (powder) and electrochemical polymerization (thin films). The composite materials were characterized by FTIR spectroscopic technique, powder X-ray diffraction technique, TGA, FESEM and EDX. XRD studies reveal AgPDC, CuPDC and ZnPDC were similar to previously reported structures whereas CdPDC was identified as a new crystal structure. FESEM analysis of powder composites revealed that the complexes were encapsulated by the microspheres of PPY with an average size of 0.5 μm whereas, analysis of the film composites revealed that the complexes were embedded irregularly within the PPY microspheres with an average size of 1.2 μm. Powder PPY and its composites were mixed with carbon black and PVDF to form slurry and coated evenly over graphite sheet as working electrode. With Ag/AgCl reference and Pt wire counter electrode, the CV was performed in room temperature at potential range of -0.2 V to +0.8 V in 1 M H2SO4 electrolyte. Thin films of PPY and its composites on ITO glass as working electrode with Ag/AgCl reference and graphite rod counter electrode was used to perform CV in room temperature at potential range of -0.5 V to +0.9 V in 0.01 M K3[Fe(CN)6] + 0.1M KCl electrolyte solution. Based on the shape of the voltammograms at 10 mV.s-1 scan rate, the powder composites exhibited improved capacitive behaviour and the film composites exhibited better pseudocapacitive behaviour than PPY. EIS of the powder composites was performed in the same electrochemical cell set-up as CV, meanwhile the films were extracted from ITO and performed directly. The conductivity values determined for PPY powder slurry was 8.62 × 10-4 S.cm-1 and for PPY film was 1.04 × 10-5 S.cm-1. Powder composites exhibited conductivity in the range of 1.03 × 10-3 – 4.41 × 10-3 S.cm-1 and film composites were in range of 4.78 × 10-5 – 2.16 × 10-5 S.cm-1. All fabricated composites achieved higher conductivities, reduced resistance, than pure PPY. These electrochemical traits are promising for their future application as supercapacitors
A comparative geochemical study of humic coals from Cenozoic Sarawak basin, Malaysia and cretaceous Benue trough, Nigeria / Asiwaju Lanre Oluwaseun
No full textAlthough humic coal is generally described as a gas-prone source rock, a significant number of oil-prone coal-bearing sequences in Australasia and Southeast Asia have expelled commercial volumes of oil. Nevertheless, the mechanism of oil generation and expulsion from humic coals remains poorly understood. Therefore, this thesis seeks to provide new insights into the geochemical controls on the petroleum potential of humic coals. A total of sixty Tertiary and Upper Cretaceous coals from Sarawak Basin, Malaysia, and Benue Trough, Nigeria were investigated using bulk and molecular geochemical techniques such as standard proximate analysis, pyrolysis-gas chromatography (Py-GC), Rock-Eval pyrolysis, Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), elemental analyser isotope ratio mass spectrometry (EA-IRMS), and inductively coupled plasma mass spectrometry
(ICP-MS) to determine their thermal maturity, hydrocarbon generation potential, organic matter input, kerogen type, paleovegetation, paleoclimate, and environments of deposition. Furthermore, principal component analysis (PCA) of geochemical parameters was carried out to evaluate the probable controls on the hydrocarbon generation potential of the coals. First, vitrinite reflectance and Tmax data, and maturity-related biomarker parameters all signify low thermal maturity for all studied coals except the Lamja Formation coals of the Benue Trough which are in the early maturity stage. Furthermore, hydrogen index ( 20 wt. %), A-factor (> 0.4) and extract yield (> 10000 ppm) data for most of the coals indicate excellent potential for gas and mixed oil and gas generation. Rock-Eval, Py-GC, and source-related aliphatic and aromatic hydrocarbon parameters indicate that the coals are derived mainly from terrestrial organic matter but with a considerable proportion of marine algal organic
matter in the Benue Trough coals. Additionally, δ13C values and the abundance of terpenoids imply the predominant contribution of gymnosperms and angiosperms to the paleoflora of the Benue Trough and Sarawak Basin, respectively. Bimetal proxies (Sr/Ba, Sr/Cu, and C-value), and δD values are generally suggestive of a warm and humid climate during the accumulation of the paleopeats. However, the presence of ≥ 6-ring combustion-derived polycyclic aromatic hydrocarbons (PAHs) in the Gombe Formation coals of the Upper Benue Trough implies relatively drier conditions during the Maastrichtian. Additionally, n-alkane proxies (Pwax, Paq, n-C23/n-C29, etc.) suggest that Liang Formation coals of the Sarawak Basin were deposited under relatively drier and strongly seasonal paleoclimate during the Late Pliocene. When compared with published global average abundances, the investigated coals are mostly depleted in major oxides and trace elements, suggesting peat accumulation in freshwater-influenced environments. Furthermore, the low to moderately high ash content of the Sarawak Basin coals indicates the presence of ombrotrophic and rheotrophic peat deposits, while the relatively higher ash content of the Benue Trough coals is indicative of prevalent rheotrophic conditions.
PCA result of selected geochemical proxies suggests that thermal maturity, source input, peat hydrology, paleoflora, and marine incursions do not influence hydrocarbon generation potential. However, climatic, and depositional conditions both appear to slightly influence the hydrocarbon generation potential of the studied humic coals
Factors influencing the financial performance of selected Islamic Banks in Malaysia and Indonesia / Fitrah Rahmatika Muslih
No full textThese days, banking industry mostly uses a dual system, conventional banking and
Islamic banking. Although Islamic banking is still relatively new compared to
conventional banks, Islamic banking is recently growing rapidly throughout the world. In
particularly, Malaysia and Indonesia are two countries with high development of Islamic
banking compared to other countries in ASEAN. In fact, Malaysia and Indonesia were
ranked as the first and the second out of 50 countries on the Islamic Finance Country
Index (IFCI) in 2020. Therefore, this study was conducted to compare the factors that
influence the financial performance of Islamic banking in Malaysia and Indonesia. The
research objectives of this study are to investigate how the comparison of the effect of
financial ratios, macroeconomics, and Shariah screening on the financial performance of
Islamic banking in Malaysia and Indonesia and to identify which would be the most
influential factor that affects the financial performance of Islamic banking in Malaysia
and Indonesia.
This study utilizes the secondary data collected from the annual financial reports of
ten Malaysian Islamic banks and ten Indonesian Islamic banks from 2015 to 2020. This
study categorized the explanatory variables into financial ratios, macroeconomics, and
Shariah screening. The financial ratio factors include Capital Adequacy Ratio (CAR),
Non-Performing Financing (NPF), and Financing to Deposit Ratio (FDR);
macroeconomics factors include inflation, Gross Domestic Product (GDP), and exchange
rate, while Shariah screening factors include Islamic investment, Islamic income, and
Profit-sharing ratio. In order to achieve the research objectives of this study, the researcher uses a panel
data multiple linear regression model to test the effect of independent variables on
dependent variables. Results have shown that for Malaysian Islamic banking’s
performance, there are three variables significantly influence the financial performance
of Malaysian Islamic banks: Capital Adequacy Ratio (CAR) of financial ratio factors,
Gross Domestic Product (GDP) of the macroeconomic factors, and Profit-sharing of
Shariah screening factors. In comparison to Indonesian Islamic banks, this study finds
that seven independent variables have a significant impact to the financial performance
of Islamic banks in Indonesia: Capital Adequacy Ratio (CAR), Non-Performing
Financing (NPF), and Financing to Deposit Ratio (FDR) of financial ratio factors; Gross
Domestic Product (GDP) and Exchange rate of the macroeconomic factors; and Islamic
investment and Islamic income of Shariah screening factors
The death penalty in the new Omani Penal Code passed by Royal Decree 7/2018 from shariah perspective: An analytical study / Malak Sultan Mohamed Alhabsi
No full textThe problem of the study is summed up in the legislation of the capital punishment in the new Omani Penal Code enacted by the Royal Decree (7/2018), despite the wide intellectual controversy stirred by the capital punishment (death penalty) because of the call of human rights organizations and many jurisprudents and jurists for the need to prevent the capital punishment. The study adopted the inductive methodology, and the analytical methodology. The study aimed to know what the capital punishment is, its legitimacy and the wisdom behind it in Islam, clarify the amendments to the new Omani Penal Code, identify its general features with regard to the capital punishment, analyze the opinions of thinkers about the capital punishment and its compatibility with the Islamic law, and find out the extent to which the capital punishment in ta’zeer is compatible with the Islamic Sharia. The study found a number of results, the most important of which are what follows. In the new Omani Penal Code issued by the Decree (7/2018), the Omani legislator considered the practical necessities that impose the retention of the capital punishment to counter the criminal cases intractable to any punitive procedure for the sake of protecting society. In addition, the mechanism with which the execution is carried out and the legal materials and penal procedures surrounding it confirm the Sultanate of Oman’s concern to implement the process Execution in full observance of the humanitarian aspects and the warranties of international law and human rights. The researcher recommends the need to activate the decisions prohibiting the implementation of the death penalty except by a final ruling issued by a competent court after legal procedures that provide all possible warranties to insure a fair trial
Formulation of final resistance of the air filters / Yit Jing Ee
No full textAir filters play an indispensable role in maintaining a good indoor air quality (IAQ) for the occupants in a building. However, a significant drawback of the air filter applications is the high pressure drop across it, causing a high energy consumption of the HVAC system. The dust cake formation on the filter media after a certain period of usage can even further increase the high energy consumption. Therefore, an accurate setpoint of the final resistance can ensure energy-saving of the system while the indoor air quality is not compromised. In the industrial practice, the final resistance is set twice the initial resistance according to ASHRAE 52.2-2020 recommendation or set using Rule of Thumbs as there is a lack of final resistance study in the literature. In this research, a pleated fibreglass air filter is studied to identify the factors affecting filtration performance and formulate the final resistance relationship. The filtration performance parameters, including the initial pressure drop, filtration efficiency, pressure drop across dust cake and the dust holding capacity of the filter, are studied experimentally and via CFD. A triangular pleat is found to have the lowest initial pressure drop, and it is found that the fibre diameter, filtration velocity, pleat density and pleat depth are the contributing factors affecting filtration performance. The empirical models of filtration performance parameters are expressed in terms of the contributing factors. The models are validated that the predicted models are acceptable as the difference between predicted and validated R2 values are only less than 1.5 %. The validated empirical models are used for the prediction in the final resistance model in consideration of the filter lifespan and the energy cost. The findings of this study can effectively provide a guideline to the filter manufacturers in the filter design stage or the filter selection stage. The filtration performance can be easily predicted by inserting the design parameters into the empirical models. The final resistance can also be determined analytically with the proposed model in consideration of the predicted filter lifespan and energy cost. The proposed filtration performance parameter models and final resistance model can provide a better filter selection for the end-users, giving a better solution in maintaining the building’s IAQ and, at the same time, minimizing the operation cost
Palm-based liquid crystals containing schiff base ester linking group: Synthesis and structure-mesomorphic properties / Lee Weng Nam
No full textIn the present study, one of the five basic building blocks of oleochemicals, palm fatty acid, was chosen as flexible moiety in the synthesis of liquid crystals (LCs) due to its good reactivity for chemical modifications and non-toxicity. Three new series of palm-based liquid crystals (PBLCs), namely, PB1 – PB3, PB4 – PB6 and PB7 – PB9 consisting of Schiff base ester-based mesogenic core have been successfully synthesized. The chemical structure of all synthesized PBLCs was characterized and confirmed by Fourier Transform Infrared Spectroscopy (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR). Polarizing Optical Microscopy (POM) revealed that the synthesized PBLCs were monomorphic and enantiotropic in nature exhibiting only smectic A phase upon heating and cooling except for PB9 in which smectic A phase can only be seen in the cooling cycle (monotropic). The phase transition temperatures observed under POM were found to be in good agreement with the Differential Scanning Calorimetry (DSC) thermograms obtained. The mesophase texture of smectic A phase was further verified by Small Angle X-ray Scattering (SAXS). The presence of a three-ring Schiff base ester-based mesogeniccore with a terminal bromo group within the series of PB1 – PB3 has led to higher molecular linearity and polarizability which eventually resulted in a stable mesophase range. As for the unsubstituted analogues of PB4 – PB6 series, the mesophase range was found to be narrower due to lower molecular polarizability with the absence of bromo group as terminal substituent. PB7 – PB9 series is composed of a mesogenic core with one less phenyl ring and an ester group. Therefore, owing to its lower molecular linearity and polarizability, PB7 – PB9 exhibited the least stable smectic A phase. As far as thermal stability is concerned, all synthesized PBLCs were found to be thermally stable above 300oC except for PB3 (decomposed with 5% weight loss at 281.66oC), PB4 and PB5 (decomposed with 5% weight loss at 201oC)
Keberkesanan strategi pemetaan semantik terhadap penguasaan kolokasi bahasa Arab / Uraidah Abdul Wahab
No full textSaiz dan kedalaman kosa kata merupakan dua dimensi ilmu kosa kata yang berkait rapat antara satu sama lain. Antara elemen kedalaman kosa kata yang penting dalam meningkatkan penguasaan kosa kata, kecekapan komunikasi dan kelancaran berbahasa seperti penutur jati adalah pengetahuan kolokasi. Namun, menjadi kesukaran kepada pelajar bahasa asing untuk menguasai pengetahuan kolokasi apatah lagi mengekalkannya dalam memori jangka panjang disebabkan keterbatasan pengetahuan penggunaan kata dan kekeliruan makna. Justeru, kajian gabungan Urutan Penjelasan ini bertujuan mengkaji hubungan saiz kosa kata dan pengetahuan kolokasi serta keberkesanan strategi pemetaan semantik (SPS) dalam pembelajaran kolokasi bahasa Arab sebagai bahasa asing bagi membantu pelajar menguasai dan mengingat kolokasi. Data kuantitatif dikumpul melalui kaedah kuasi eksperimen ujian pra-pasca, manakala data kualitatif diperolehi melalui kaedah tinjauan temu bual semi struktur. Subjek kajian terdiri daripada 150 orang pelajar Sijil Tinggi Agama Malaysia (STAM) di Sekolah Agama Bantuan Kerajaan (SABK). Dapatan kajian menunjukkan bahawa saiz kosa kata kumpulan eksperimen dan kawalan berkorelasi secara signifikan (r=.73,.78,p=.000) dengan pengetahuan kolokasi bahasa Arab bahkan perhubungan ini adalah positif yang kuat. Analisis statistik turut membuktikan bahawa keberkesanan penggunaan strategi pemetaan semantik bukan sekadar mempengaruhi tahap penguasaan kolokasi bahasa Arab secara individu (UJIAN [F(1.94,287.90)=2249.90, p<.05]), malah memberi kesan interaksi kepada penguasaan kolokasi bahasa Arab dan pengekalannya dalam memori jangka panjang secara berkumpulan (UJIAN*KUMPULAN [F(1.95,287.90)=1586.43, p<.05]). Berdasarkan penjelasan dan keupayaan pelajar membezakan ciri pemetaan semantik dengan strategi pembelajaran lain, membuktikan bahawa mereka telah melalui proses pengecaman dan kesedaran kolokasi. Implikasi kajian ini jelas menunjukkan bahawa wujud keserasian strategi pemetaan semantik dalam pembelajaran kolokasi leksikal bahasa Arab melalui penekanan aspek perkaitan antara konsep, pengelompokan dan kefasihan berbahasa
Mediation-moderation model of trust in colleagues and emotional intelligence on the relationship between professional learning communities, collective efficacy and job satisfaction among Malaysian primary school teachers / Nidhi Singh
No full textIn the Malaysian Education Blueprint (2013 - 2025) the government has emphasized the need of improving students' academic outcomes to drive equivalence with international standards. To achieve this goal, it is important to establish, evolve and cultivate professional learning communities at schools, as they directly affect teachers' collective efficacy beliefs and job satisfaction, the two most important factors responsible for students' academic outcomes. However, Malaysian research literature shows a clear gap for the impact of professional learning communities on schools, teachers, and students. Therefore, this study aimed to understand the relationship between these variables. The main research objectives were: (1) to examine the direct relationship between professional learning communities, teachers' collective efficacy, and job satisfaction, (2) to identify the significant mediating role of teachers' trust in colleagues, and (3) to identify the significant moderating effect of teachers' emotional intelligence. The study used Bandura’s social cognitive theory to conceptualize the relationship between the variables. In this causal relationship study, questionnaires were used for data collection and a total of 307 primary school teachers participated in the study. The research instruments used for the study included English and Malay versions of the teachers' demographic information, Professional Learning Communities Assessment-R, Collective Teacher Belief Scale, Spector's Job Satisfaction Survey, Omnibus-T Scale, and Wong & Law Emotional Intelligence Scale. A total of 18 primary schools from the state of Selangor were randomly selected to participate in this study. Descriptive data analysis was performed using the software Statistical Packages for the Social Sciences (SPSS). Thereafter, structural equation modeling (SEM) using SmartPLS was done to study the direct, mediating, and moderating effects between the variables. Study findings confirmed the presence of professional learning communities (Mean = 3.25; SD = 0.42) at primary schools in Selangor, Malaysia. Also, teachers reported moderate to high levels of collective teacher efficacy (Mean = 7.09; SD = 0.94), trust in colleagues (Mean = 5.04; SD = 0.63), and perceived emotional intelligence (Mean = 5.73; SD = 0.61) and overall satisfaction with their job (Mean = 4.54; SD = 0.58). A direct and positive relationship was found between professional learning communities and collective teacher efficacy ( = 0.25; p<0.01), which was significantly mediated by trust in colleagues ( = 0.22; p<0.01) and between professional learning communities and teachers' job satisfaction ( = 0.28; p<0.01), mediated by trust in colleagues ( = 0.23; p<0.01). Teachers' perceived emotional intelligence significantly but negatively, moderated the relationship between professional learning communities and job satisfaction ( = -0.08; p<0.05), however, moderating effect for professional learning communities and collective teacher efficacy was insignificant. This study shows that professional learning communities can benefit teachers, policymakers, and schools in achieving desired academic outcomes for Malaysian students. The present study highlights the importance of maintaining trust relationships at schools and the possible benefits of teachers’ participation in emotional intelligence programs. Finally, implications of the study and recommendations for future research were presented
Integrated multiband front-end radio frequency energy harvesting system for low-power IOT devices / Lian Wen Xun
No full textThe rapid growth of the Internet of Things (IoT) has driven the expansion of wireless sensor networks (WSNs). However, traditional battery-based power sources for WSNs are impractical due to their physical size and life-cycle limitations. As a result, energy harvesting has emerged as a viable renewable solution by converting ambient energy into usable electrical energy. Among all the energy harvesting sources, such as solar, thermal, kinetic, and Radio Frequency (RF), RF stands out as a suitable choice for WSNs due to its availability, especially when there is data communication; then, there will be RF energy. RF energy harvesting (RFEH) systems, consisting of crucial blocks such as the impedance matching network (IMN) and rectifier, plays a vital role in energy conversion. While most existing RFEH designs are off-chip, on-chip implementations are preferable for biomedical implants and IoT applications. Furthermore, relying solely on a single-band RFEH system limits the practicality when RF energy fluctuates, or the RF at the desired frequency is unavailable. Therefore, the development of multiband RFEH systems becomes crucial to address these challenges. In CMOS rectifier design, achieving high sensitivity for initiating the scavenging process is essential. Current rectifier topologies involve trade-offs such as the number of stages, transistor types, harvesting frequency, and enhancement techniques. The sensitivity of CMOS rectifiers to scavenge RF energy from longer distances requires further improvement. Moreover, extending the power dynamic range (PDR) of CMOS rectifiers presents challenges in performance trade-offs. To address these research gaps, this work aims to develop a novel mathematical design formulation for on-chip multiband IMN, along with a high- sensitivity cross-coupled differential drive (CCDD) rectifier and a wide PDR reconfigurable CMOS rectifier. The proposed mathematical model addresses the gaps in IMN design formulation for multiband RFEH systems. The designed tri-band RFEH system achieves peak power conversion efficiency (PCE) of 42.8%, 37.1%, and 30.4% at 900MHz, 1.9GHz, and 2.4GHz, respectively. The fabricated CCDD rectifier demonstrates a sensitivity of -22dBm and peak PCE of 86% at 900MHz. Furthermore, the novel reconfigurable rectifier achieves a PDR of 23dB with a peak PCE of 88.7%
Penerokaan seni grafiti dalam membantu mengurangkan gangguan emosi murid sekolah rendah di Kuala Lumpur / Chan Min Xuan
No full textEmosi dalam diri seseorang murid merupakan elemen yang penting bagi mewujudkan pembelajaran dan pemudahcaraan (PdPc) yang berkesan. Namun didapati semakin ramai murid sekolah rendah yang menghadapi masalah gangguan emosi kerana masalah peribadi, masalah keluarga, masalah rakan dan media sosial serta masalah guru dan sekolah sehinggakan guru perlu memikirkan solusi untuk membantu mereka. Kajian ini bertujuan untuk meneroka penggunaan seni grafiti dalam membantu mengurangkan gangguan emosi murid sekolah rendah di Kuala Lumpur. Secara khususnya, kajian mencadangkan reka bentuk seni grafiti sekolah rendah, proses penghasilan dan implementasi seni grafiti terhadap emosi murid. Kajian berbentuk kualitatif telah dijalankan di sebuah sekolah rendah dengan melibatkan empat orang murid. Peserta kajian dipilih secara persampelan bertujuan berdasarkan prestasi dalam kelas dan ujian minda sihat. Data dikumpul dengan menggunakan kaedah analisis dokumen, pemerhatian dan temu bual. Data kajian dianalisis secara deskriptif. Dapatan kajian menunjukkan reka bentuk seni grafiti yang digunakan oleh murid sekolah rendah ialah reka bentuk huruf dan gabungan. Pemilihan adalah berdasarkan kefahaman dan kebolehan mereka dalam seni huruf. Menerusi dapatan, proses menghasilkan grafiti oleh murid-murid sekolah rendah diperlihatkan dalam lima langkah, iaitu proses penyediaan awal, proses eksperimentasi, proses melakar, proses mewarna dan proses pengemasan dan penambahbaikan. Berdasarkan proses penghasilan karya yang dilakukan, didapati emosi murid adalah positif dan bertambah baik khususnya dari aspek keyakinan, motivasi dan kepuasan murid semasa proses penghasilan seni grafiti. Konklusinya, seni grafiti dapat membantu mengurangkan gangguan emosi murid-murid sekolah rendah dengan mengekspresikan emosi masing-masing dengan kaedah yang menarik. Guru-guru boleh merancang aktiviti seni grafiti bagi murid-murid dengan mengambilkira reka bentuk dan proses untuk menghasilkan seni grafiti dari kajian ini. Justeru, kajian mencadangkan supaya seni grafiti boleh digunakan sebagai terapi untuk murid sekolah yang menghadapi masalah emosi dan boleh diperluaskan di sekolah menengah