13474 research outputs found
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Behaviour of S-types shear connector in composite precast concrete sandwich wall panels / Herman Tawil
No full textPrecast concrete sandwich wall panels (PCSPs) have gained popularity in building exteriors due to their commendable thermal efficiency, composite performance, and cost-effectiveness in terms of manufacturing and maintenance. In a continuous effort to enhance efficiency and reduce material usage, researchers have explored into the possibility of decreasing panel thickness while maintaining thermal efficiency and ensuring the strength of cladding components. However, the critical aspect of shear connection, particularly involving steel plates, which is essential for durability and energy efficiency, has not received sufficient attention in existing research. This study focuses on investigating the shear behavior of PCSPs with an S-type shear connector (SSC), combining nine push-off tests with nonlinear finite element modelling using the Abaqus software. Parametric analyses were undertaken with the development of 192 models to investigate how the geometric properties of the SSC, steel yield strength, and insulation thickness affect the overall performance. The study findings provide interesting information. The maximum secant stiffness for SSCs is found to be achieved when the connector has a width of 101.4 mm and a thickness of 2 mm. Consequently, the study recommends that the width of SSCs should be constrained to this specific value or lower to optimize their performance. Furthermore, the research indicates that increasing steel yield strength beyond a thickness of 2 mm and a width of 101.4 mm does not yield additional benefits; instead, it adversely affects the secant stiffness of the SSCs. In essence, this research contributes valuable knowledge to the design and optimization of PCSPs, shedding light on the specific parameters that influence the shear behavior of these panels when utilizing an S-type shear connector. The findings provide practical recommendations for engineers seeking to strike a balance between material efficiency and structural integrity in the construction of building exteriors using precast concrete sandwich wall panels
A pilot scale study of low dissolved oxygen oxic-anoxic process for biological nitrogen removal from tropical sewage / Leong Chew Lee
No full textComplying with nitrogen effluent discharge limits in domestic sewage treatment comes with high energy and chemical costs. Conventional biological nitrogen removal (BNR) process, which maintains high dissolved oxygen (DO) concentrations (>2 mg/L), often consumes half of the total plant’s energy for aeration. Stakeholders in the sewage industry are seeking ways to improve energy sustainability. Low-DO oxic-anoxic (low- DO OA) meets the criteria as a simpler, cost-effective and efficient biological treatment process due to its operation at low DO level (<1 mg/L). The lab-scale low-DO OA reactor completely removed ammoniacal-nitrogen (NH4-N) and produced low effluent nitrate-nitrogen (NO3-N) when treating local sewage. However, the feasibility of the low-DO OA process has yet to be validated at a scaled-up level for nitrogen removal. This project aimed to evaluate the feasibility of an on-site pilot-scale low-DO OA process in treating domestic sewage with low chemical oxygen demand-to-nitrogen ratio (COD/N) in tropical climate. Despite the low COD/N influent sewage, further denitrification experiments revealed that slowly biodegradable COD (sbCOD), predominantly present in particulate settleable solids (PSS) in domestic wastewater, can effectively support nitrogen removal efficiency. Nitrification batch tests demonstrated that operating the BNR at low DO concentrations is feasible. Nitrifiers from low DO sludge samples have a higher oxygen affinity with a lower half-saturation constant
Influential factors in designing an immersive speech sound intervention method for young learners / Noormala Anuar Ali
No full textMastery of consonants production is a vital for children's speech development. Any sound errors lead to reduce speech clarity in verbal communication, which implies difficulty in learning, social interaction, and psychological problems. Several speech sound intervention (SSI) methods have been introduced to treat childrens’ speech. Auditory perception, cognitive-linguistic, and speech production approaches are usually utilized. This study aims to determine the influential factors in designing an immersive speech sound intervention (I-Speech) method for young learners. Factors selected were based on literatures, experts’ judgement process, and survey study to evaluate the consistency, reliability, validity, and correlation among the variables. Partial Least Square - Structural Equation Modeling (PLS-SEM) analysis resulted I-Speech instrument was valid, reliable, and internally consisitent. Moreover, two factors; speech sounds development (SD), and speech sounds errors (SE) have significant positive influence on target sound selection (TS). Meanwhile, another three factors were significant predictors for promote success of speech production (PS), there are auditory perception (AP), speech production (SP), and immersive learning (IL). This study manages to pioneer an innovative I-Speech model as a reference to implement SSI. In addition, the results contribute implication to instructional with the publication of learning module for speech sound intervention method. Future research may further explore the potential to implement the I-Speech model for elementary education and early intervention program
Load shedding scheme based on meta-heuristic techniques and multi-criteria decision making for islanded distribution systems / Hazwani Mohd Rosli
No full textIn modern power systems, ensuring stability during contingencies is essential for maintaining a reliable and secure operations. This study introduces a new Load Shedding Scheme (LSS) that incorporates advanced techniques to enhance system stability under adverse conditions. The proposed LSS utilizes discrete meta-heuristic techniques to intelligently select critical loads for shedding. It considers both voltage stability index and power mismatch as fitness functions. Among the techniques employed, Binary Zebra Optimization Algorithm (BZOA) demonstrates the best performance, as evidenced by its capability to achieve both minimum fitness values and minimum standard deviation. Multi-criteria decision-making approaches, including the Analytic Hierarchy Process (AHP) and the Weighted Sum Model (WSM), rank loads based on its priority, stability index, and sizing. The proposed LSS has undergone comprehensive testing on the 11 kV Malaysian distribution system for both 30-bus and 102-bus systems. The testing involved the utilization of various stability indices for assessing performance in both islanding and overloading events. Results consistently demonstrate that the proposed LSS outperforms adaptive techniques across all stability indices, showcasing superior frequency response characteristics. A significant improvement was also observed in both stability index values and voltage profiles for buses that underwent load shedding. Diverse scenarios were also investigated to assess the versatility of the proposed scheme. In an increased load scenario, the LSS adeptly prioritizes nonvital loads for shedding, effectively ensuring stable system operation with the system voltage approaching to 1.0 p.u. Additionally, the proposed scheme exhibits remarkable frequency recovery in scenarios involving both loss of synchronous and induction generator. Comparative analyses with previous techniques highlight the superiority of the proposed LSS in terms of rapid frequency recovery by as much as 73.75% and 28.51% for the 30-bus and 102-bus systems, respectively, compared to the adaptive technique
Minimizing charging cost of plug-in electric vehicle based on ensemble machine learning techniques and optimal control / Ali Najm Abdulnabi Alkawaz
No full textPlug-in Electric Vehicles (PEVs) offer an environmentally friendly alternative to conventional internal combustion engine vehicles, promising reduced greenhouse gas emissions and conservation of oil reserves. However, their increasing integration into the electric grid raises concerns about stability and reliability owing to heightened charging demands. Random or uncoordinated charging within the distribution network can exacerbate these challenges, leading to increased charging costs for PEV owners and potential strain on the grid. In the present study, a smart and coordinated charging approach with centralized control is proposed, aimed at minimizing charging costs and supporting grid stability. This is achieved using the optimal control (OC) technique, considering fixed fluctuations in electricity prices and various driving patterns. Empirical results indicate that, compared to a random charging plan, smart and coordinated charging strategies can reduce charging costs by up to 73% and 21%, respectively. A new hybrid machine learning (ML) model was proposed for electricity price forecasting (EPF) to further optimize charging costs. It integrates the linear automatic relevance determination (ARD) model, addressing trend and seasonality, with the ensemble bagging extra tree regression (ETR) model, capturing interactions. Validated with a Nord Pool market dataset, this approach surpassed other hybrid models, achieving reductions in testing mean absolute error and root mean square error values by 32.1% and 21.5%, respectively. Random PEV charging activities are well-recognized for their potential impacts on both vehicle owners and electric networks, resulting in elevated charging costs and degraded distribution system performance such as power loss, and voltage deviation. To address these challenges, scheduling of PEV charging activities is essential. Coordinated and smart charging strategies incorporated with EPF using ML and OC methods have been devised. These strategies not only lead to cost savings for PEV owners but also benefit electric utilities. To guide PEV charging decisions based on price forecasts, three ML classifiers were employed: neural network, naïve Bayes, and an ensemble approach. Empirical results show that the ensemble ML classifier outperforms its counterparts in various charging strategies. Remarkably, the proposed ensemble smart charging strategy recorded a PEV charging cost of £15, which was significantly lower than the £280 incurred using the random charging strategy. Moreover, compared to the base random charging case, the proposed ensemble-based smart and coordinated approaches reduced the charging cost by approximately 94% and 40%, respectively. To illustrate the impacts of the proposed coordinated and smart charging techniques compared to random charging at various levels of PEV penetration levels (16%, 28%, and 41%), both modified and standard IEEE 69-bus radial distribution systems were employed, smart and coordinated PEV charging showcased better performance in terms of power consumption, voltage drop, and system loss than those of random charging. Overall, this study indicates that an ensemble-based coordinated and smart PEV charging strategy is a promising approach for efficiently managing electricity usage. As PEV adoption increases, smart charging technologies are likely to become more widespread and help drive the transition to a more sustainable energy future
Reka bentuk pembelajaran berasaskan khidmat untuk Pendidikan Moral sekolah menengah / Leong Hooi Li
No full textPengajaran dan pembelajaran Pendidikan Moral menekankan tiga domain moral iaitu penaakulan moral, emosi moral dan perlakuan moral untuk membentuk insan berakhlak mulia. Namun begitu, guru Pendidikan Moral sering menekankan penaakulan moral dan bukannya emosi moral dan perlakuan moral. Justeru, kajian ini mencadangkan reka bentuk Pembelajaran Berasaskan Khidmat (PBK) atau lebih dikenali Service Learning sebagai pendekatan pengajaran yang menghubungkan teori dan amalan dengan memberi peluang kepada pelajar kedua-duanya untuk mengambil bahagian dalam perkhidmatan yang memenuhi keperluan komuniti. Kajian ini menggunakan Aplikasi Fuzzy Delphi (FDM) dengan 15 pakar dari bidang sains sosial dan mempunyai pengalaman PBK untuk menentukan objektif pembelajaran, kandungan pelajaran, strategi pembelajaran dan penilaian pelajaran sebagai garis panduan bagi Pendidikan Moral sekolah menengah. Dapatan kajian menunjukkan bahawa keempat-empat konstruk utama telah mendapat kesepakatan pakar adalah melebihi 75%, nilai Threshold (d) <0.2 dan α–cut melebihi 0.5. Reka bentuk yang dicadangkan adalah garis panduan yang relevan dalam memperkenalkan PBK di sekolah menengah. Ini menunjukkan bahawa keempat-empat konstruk utama ini diperlukan dalam mengintegrasikan PBK sebagai wadah dalam mata pelajaran Pendidikan Moral
Anti-inflammatory effect of single and combined Christia vespertilionis leaf extract and palm tocotrienol-rich fraction / Izzah Farhah Zambari
No full textChristia vespertilionis were used traditionally to treat inflammation. Non-Steroidal Drugs (NSAIDs) are commonly prescribed to treat inflammation. However, long-term prescription of these NSAIDs will lead to adverse side-effect. This study was performed to evaluate anti-inflammatory properties of C. vespertilionis leaves besides purifying its protease and to determining its anti-inflammatory effect through in vitro and in vivo studies of extract combination with palm tocotrienol-rich fraction (TRF). Result showed that C. vespertilionis extract analysed using GC-MS contain anti-inflammatory compounds. Enzymatic protease was successfully extracted and purified through ammonium sulphate precipitation with further dialysis increases its yield by 53 % with specific activity 14.33 U/mg. The combination between C. vespertilionis protease (CVP) and palm tocotrienol-rich fraction (TRF) were tested synergistically to reduce inflammation were done through in vitro and in vivo studies and it shows that the combination of CVP and TRF (CVP+TRF) at the ratio of 14.10:8.48 μg/mL, gives 50 % inhibition (IC50) of nitric oxide (NO). In conclusion, this study managed to show the synergistic effect of the combination of CVP and TRF against LPS-stimulated RAW264.7 cells and carrageenan-induced BALB/c paw oedema. The treatment could be potentially effective in reducing inflammation, and thus could be an alternative approach to NSAIDs drugs
Antiproliferative effects of curcuma purpurascens on H103 and its interaction mechanism with human serum albumin / Nurul Jannah Mohd Asngari
No full textCurcuma purpurascens (C. purpurascens) commonly known as Temu tis is extensively utilised in Southeast Asian for culinary and therapeutic applications of diverse ailments, including cancer. In the present study, the possible mechanisms underlying the cytotoxic effects of C. purpurascens extracts against H103 human oral squamous carcinoma cells were investigated. The cytotoxic effects of the crude methanol and fractionated extracts (hexane, chloroform, ethyl acetate and water) of C. purpurascens against several human oral cancer cell lines and non-cancer gingival fibroblast cells were conducted using the MTT assay. The C. purpurascens chloroform fractionated extract (CPCE) was selected for further investigations on the induction of apoptosis as it exhibits high cytotoxicity effect against H103 cancer cells. The CPCE was also selected for further investigations on the interactions with human serum albumin (HSA) along with ar-turmerone and odanacatib (ODN) as comparison using spectroscopic, microscopic, and molecular docking approaches. Morphological observations by an inverted phase contrast microscope and double staining assay in the treated H103 cancer cells with the CPCE exhibited typical apoptotic morphology such as cell shrinkage, chromatin condensation and membrane blebbing. Flow cytometry analysis of CPCE-treated H103 cancer cells showed that apoptosis was triggered by the externalization of phosphatidylserine, significant disruption of mitochondrial membrane potential and DNA damage. The activation of caspases-3, -8 and -9 implied the trigger of both extrinsic and intrinsic pathways in the CPCE-treated H103 cancer cells. Furthermore, CPCE was able to induce cell cycle arrest in H103 cancer cell at G2/M phase. Both CPCE and ar-turmerone binding to HSA quenched the protein fluorescence intensity, but only HSA spectrum at 90 μM ar-turmerone yielded a 2 nm blueshift. In contrast, ODN binding to HSA resulted in fluorescence enhancement and 4 nm blueshift. Since CPCE is composed of many compounds, it binds to HSA with a low binding constant (Ka) value of (1.27±0.05) × 102 mg/l. A moderate binding affinity was obtained for ar-turmerone-HSA and ODN-HSA binding, with Ka values of 104 M−1. CPCE and ODN binding to HSA caused the hyperchromic effect and ar-turmerone binding caused the hypochromic effect of the HSA’s absorption mainly near the Trp residue, indicating a static mechanism interaction. Circular dichroism results suggested that the overall secondary and tertiary structures of HSA remained unaltered or slightly altered upon CPCE, ar-turmerone and ODN binding. The presence of CPCE, ar-turmerone and ODN causes aggregation on the HSA’s surface morphology confirming the complex formations. Ar-turmerone and ODN showed competitive behaviour as they preferably bind to site III in subdomain IB of HSA. Their interactions were mainly stabilised by hydrogen bonds, hydrophobic and van der Waals forces. Conclusively, these findings suggest CPCE possesses a potential therapeutic role in treating oral cancer. The characterisation of CPCE, ar-turmerone and ODN binding to HSA provide a better understanding on the interaction mechanism of these ligands in blood circulation and their pharmacokinetics properties that may enhance their solubility, reduce the side effects and help in designing new therapeutic drugs for various diseases, particularly in cancer treatments
Knowledge, attitude, and practice of traditional and complementary medicine among university students in Malaysia / Kanchana Raviendran
No full textIn Malaysia, Traditional and Complementary Medicine (T&CM) is gaining popularity and expanding its role in addressing both physical and mental health issues, while also enhancing overall well-being. With the increasing interest in T&CM and its potential integration into conventional healthcare, understanding university students' perspectives is essential. This study aimed to assess the knowledge, attitudes, and practices of T&CM among university students in Malaysia. This study was conducted on 392 university students from all over Malaysia. A self-administered questionnaire was used to gather the data and descriptive analysis was applied using SPSS. The study revealed that university students in Malaysia generally hold a positive attitude towards Traditional and Complementary Medicine (T&CM) and are supportive of its integration with conventional medicine. Specifically, 66.9% of students expressed a positive view of T&CM. Knowledge levels varied significantly among different T&CM modalities. For instance, 36.7% of students had good knowledge of massage, while only 0.3% were well-informed about Unani medicine. Massage, aromatherapy, and herbal medicine were the most frequently practiced, reflecting their widespread acceptance and perceived effectiveness. In contrast, practices like hijama and Unani medicine were less commonly used. This study reveals growing interest and positive attitudes of university students toward T&CM. While there is a general willingness to integrate T&CM with conventional medical practices, there are notable gaps in students' knowledge about various T&CM modalities and their associated safety and efficacy. To address these, universities should implement targeted educational programs that provide detailed information on various T&CM modalities, including their benefits, safety, and effectiveness, to improve students' knowledge and support informed decision-making in integrating T&CM with conventional healthcare
Mandarin language teaching and learning in two Indonesian public universities / Du Yu
No full textIndonesia is a country in Southeast Asia with a large Chinese community that includes many native Chinese language speakers. In Indonesia, Chinese language education has undergone a tumultuous development process. The purpose of this study is to examine how two public universities in Indonesia, i.e. Universitas Negeri Jakarta (UNJ) and Universitas Negeri Surabaya (UNESA), have developed their Chinese language programs. Drawing upon the SWOT analysis theory, this research delves deeper into the strengths, weaknesses, opportunities, and challenges of Chinese language courses in these two public universities in Indonesia. The primary data for this study was collected through survey questionnaires administered to a sample of current and graduated students from Chinese language departments in two public universities in Indonesia. Qualitative data was gathered through interviews conducted with department heads and Chinese language instructors. Secondary data was obtained from books, journal articles, and dissertations related to the study of Chinese education. The research findings reveal the strengths, weaknesses, opportunities, and challenges faced by the Chinese language departments in these two public universities during their development process, and provide strategies for further improvement in these areas. Finally, considering the context of the "Belt and Road Initiative" (BRI), this study offers insights and recommendations for the future development of the Chinese language in Indonesia. The data and conclusions of this research can serve as a resource for future researcher