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Formulation of a novel lightweight foamed composite based on by-product gypsum / Zhang Longjian
No full textBy-product gypsum is a solid waste generated from various industrial processes and contains mostly calcium sulfate. The storage and utilization of by-product gypsum has become a bottleneck restricting the development of industries that produce it. One common form of by-product gypsum is phosphogypsum (PG), generated from the production of phosphoric acid. Over 120 million tons of PG are produced annually worldwide, but it has a very low utilization rate. The effective utilization of this solid waste poses significant environmental challenges. At the same time, the construction industry is seeking sustainable and cost-effective alternative building materials to reduce reliance on natural resources. To address these issues, this study aims to develop a novel lightweight foamed composite using by-product gypsum as a primary resource, exploring its potential as a viable alternative to brick for non-load bearing applications in the construction industry. In this study, PG was initially subjected to calcination at different temperatures ranging from 100°C to 220°C. X-ray diffraction analyses confirmed complete dehydration occurred at 180°C, transforming PG to the hemihydrate form and the calcined PG had comparable strength as commercial building gypsum. Then, composite mixtures were prepared by incorporating calcined PG as the primary binder material, along with the addition of other materials such as ground granulated blast furnace slag (GGBS), recycled waste glass (RWG), and various types of fiber, namely polyvinyl alcohol fiber (PVA), basalt fiber, and glass fiber. The mixture variables included hemihydrate PG (HPG) content (60%-100%), GGBS replacement levels (0%-25%), RWG variation levels (0%-24%), and fiber additions (0%-1.35% by volume). The incorporation of 25% GGBS and 15% OPC as supplementary binder materials, along with 24% RWG as addition further improved water resistance of the PG-based composite without compromising strength. Fiber additions, especially 1% PVA fiber, enhanced flexural strength and limited cracks in PG-based composite at elevated temperatures up to 850°C. Besides that, foamed composite mixtures containing hydrogen peroxide as a foaming agent and calcium stearate as a foam stabilizer to study their effects. The inclusion of 1.5% hydrogen peroxide and 20% calcium sterate led to 55% lower bulk density but 66.2% lower thermal conductivity insulation and 45.5% better sound absorption, compared to the matrix without hydrogen peroxide and calcium sterate addition, due to increased number of pores and the more uniform distribution of those pores. Lastly, a novel lightweight brick developed from the optimized mixture containing 60% HPG, 15% OPC, 25% GGBS, 24% RWG, 1.0% PVA fiber, 1.5% hydrogen peroxide, and 20% calcium stearate exhibited bulk density (890 kg/m3) and compressive strength (5.2 MPa) was produced, meeting non-load bearing application along with lower thermal conductivity (0.238 W/m·K). Additionally, the developed brick presented no environmental threat, as it complied with the specified limit for leaching of heavy metals and adhered to safety standards for radionuclide content. This study thus systematically provides a better understanding of utilizing solid waste PG to produce a novel lightweight foamed composite, promoting the development of eco-friendly building material
A study of the variants of /r/ in Klang Valley Malay / Katherine Schmittauer
No full textThe Malay language has rich phonological variation based on geographic and social context. Previous research has identified /r/ as the consonant phoneme with greatest variation. This study aimed to combine perceptual and acoustic analysis to more accurately quantify the variants of /r/ used in the Klang Valley and to correlate the usage of these variants with social variables. Data collected consisted of speech recordings of two styles of speech and information about the speakers’ age, gender, educational and language background. Findings suggest that the variants of /r/ correlate with phonetic environment, age, gender, and language background. The study identified four rhotic variants including the tap [ɾ], trill [r], approximant [ɹ], and a zero-realization. The appearance of the approximant [ɹ], not previously documented in Peninsular Malay, possibly indicates a linguistic change in progress. The study was limited by the size of the sample and relative homogeneity of the speakers’ backgrounds
Curing profile optimization of silver epoxy die attach in ball grid array package process / Ng Qian Qing
No full textBall grid array (BGA) packages are essential components in automotive applications, renowned for their compact form factor and high-density interconnections. However, the persistent issue of void formation within these packages poses a significant challenge to their performance and reliability. This challenge is primarily rooted in incomplete reactions between the die attach epoxy and the resin, resulting in the presence of unreacted curing agents. When exposed to moisture, these residual agents can trigger substrate surface degradation, potentially leading to critical electrical failures. This research endeavours to address the challenge of void reduction in 3‐IC‐Chip‐ MAPBGA packages, a subset of Ball‐Grid‐Array (BGA) packages, through systematic manipulation of epoxy curing parameters. The silver conductive epoxy used in this study possesses a composite structure consisting of cross-linked polymers with strong covalent bonds. Six cells, each containing eight samples, underwent testing. Four of these cells were subjected to two-step curing profiles, while two cells, including a control sample, were treated with single-step profiles. Post‐curing, comprehensive performance testing revealed the superior efficacy of two‐step profiles in void mitigation. The two-step curing profile is better than the single step curing profile because it allowed for a controlled, gradual curing process that reduced internal stress, improved outgassing of volatile components, and ensured thorough, uniform cross-linking of the epoxy. This resulted in fewer voids and enhanced the overall reliability and performance of the BGA packages. Specifically, Cell#3 and Cell#4, both utilizing two-step curing profiles with different first-step temperatures, exhibited minimal void formation percentages of 4.22% and 3.61%, respectively, compared to the control sample's 10.33%. The highest shear strength, reaching 97 MPa, was observed for Cell#4 at 25 °C. Additionally, Cell#4 exhibited a minimal percentage degradation of 3.6% in die shear strength when tested at the elevated temperature of 80 °C. The processing time for Cell#4 was found to be 105 min, the second shortest after the control sample, which had a processing time of 60 min. Overall, Cell#4, processed through a two‐step curing method, demonstrated optimal performance. Its curing conditions with higher first step ramp time and lower first step temperature is highly recommended for BGA packages, especially in high‐density interconnect applications within compact ICs, a common feature in the automobile industry. These findings pinpoint the optimal curing profile for the die attach process, strategically aimed at minimizing void formation within the package
Lower limb muscle responses by transcranial magnetic stimulation-evoked KNEE extension using mechanomyography / Zafirah Zakaria
No full textMechanomyography (MMG) and transcranial magnetic stimulation (TMS) are two non-invasive techniques that measure the mechanical responses of skeletal muscles and stimulate the motor cortex, respectively. Combining these methods can provide a more comprehensive understanding of the relationship between neural pathways and the muscular system, with potential applications in rehabilitation and the development of new treatments for muscle-related disorders. The primary objective of this study was to investigate whether specific motor control points in the motor cortex are necessary to generate a significant MMG peak amplitude (the maximum amplitude) that can produce functional muscle contractions leading to movement. Additionally, we aimed to analyze the relationship between TMS intensity and mechanical muscle output by analyzing the MMG mean peak amplitude and knee extension angle produced. Fourteen participants with no known neuromuscular or cognitive disorders underwent TMS with varying stimulation locations and intensities at a resting state throughout. This study found that specific point mapping of TMS locations did not produce significantly different muscle output compared to localization mapping, indicating that the location of motor control stimulation during TMS may not need to be specific to produce significant muscle outcomes. Despite the absence of voluntary contraction during the TMS procedure, MMG Mean Peak Amplitude increased with TMS intensity, and a specific threshold was identified at which the MMG Mean Peak Amplitude is significant and knee extension movement is present. This indicates that TMS can activate a sufficient number of motor neurons to produce a measurable mechanical response by the muscles, supporting the use of TMS for investigating the relationship between muscle output and joint angle during movement. This study also investigated whether there were differences in MMG Mean Peak Amplitude and knee angle responses to TMS-evoked contractions between active and sedentary groups, as well as between male and female participants. We found out that active participants and males had a lower threshold for TMS to produce a significant
mechanomyography response, likely due to greater cortical excitability in these groups. Overall, the findings suggest that TMS with mechanomyography has potential implications for the development of innovative approaches in studying and enhancing muscle function, particularly in individuals with neuromuscular disorders. By providing a direct measure of muscle output, mechanomyography can help quantify the effectiveness of motor rehabilitation programs. This study contributes to the understanding of the underlying mechanisms of muscle contraction and the use of TMS with mechanomyography in clinical settings
A reliable time base routing framework with seamless networking operation for SDN / Nauman Khan
No full textThe rise of software-defined networking (SDN) has revolutionized the networking industry, offering agility and flexibility through programmable networks. As SDN adoption increases in enterprise and telecom sectors, organizations face challenges in maintaining network productivity during switch and router maintenance and upgrades and in traditional networks, also known as distributed network. This thesis presents a preventive maintenance time-based routing framework (PMTRF) to optimize the recovery of data plane failures in SDN-based networks during maintenance, such as multiple links or switch failures. The proposed framework addresses the limitations of traditional reactive and proactive approaches and focuses on enhancing backup path reliability and isolating the maintenance switch during maintenance time. By dynamically calculating the reliability of backup paths based on switch port fluctuations, the PMTRF ensures seamless and reliable network operations during maintenance. It is framed as a mixed-integer linear programming problem. To address this complexity, this work presents a multi-objective heuristic algorithm in the framework with the help of other module inputs that efficiently determines the best path for upcoming affected flows and timely isolates the maintenance switch except for the critical switch. PMTRF modules and their algorithms enable the isolation of the maintenance switch and the selection of the most reliable path for future affected flows based on input time provided by the administrator. By incorporating this approach, efficient and effective network recovery is ensured. Furthermore, identifying critical switches and their locations offers valuable information to the administrator, enabling them to avoid endto- end reachability issues during maintenance activities in the network. This work includes comprehensive experiments to assess the effectiveness of the proposed PMTRF approach. The results validate our approach’s superiority over previous methods across various performance metrics. Specifically, PMTRF approach achieves notable improvements in end-to-end delay, reducing packet loss. Additionally, it significantly reduces failure recovery time to less than 50 ms for carrier-grade networks. The proposed approach optimizes switch resource utilization by effectively managing additional flow rules in switches. Furthermore, PMTRF exhibits its resilience and adaptability to changing network conditions, accurately detects faulty switches, which is useful for fore-cast switch failures based on switch reliability within the network. By adopting PMTRF, organizations can achieve seamless and reliable network operations during maintenance, reducing downtime, increasing reliability, and improving overall network performance. This research makes a significant contribution to the field of SDN and opens avenues for future advancements in this area
Facial micro-expression spotting and recognition using deep learning / Liong Gen Bing
No full textFacial Micro-Expressions (MEs) are subtle involuntary actions that reveal a person’s hidden emotions in high-stakes situations within a fraction of a second. The diverse range of practical applications has garnered significant interest among researchers. However, limited research exists on ME analysis in untrimmed video datasets, where the challenge lies in seamlessly spotting the MEs and recognizing the associated emotions within videos containing unrelated facial movements. Furthermore, despite the recent emergence of multimodal ME datasets with an additional depth dimension, the exploration of ME analysis in line with 3D human visual perception remains subdued. Additionally, the scarcity of labeled ME samples presents a challenge to developing robust networks. These limitations are addressed explicitly in this thesis. This thesis proposes a network architecture named the Micro-Expression Analysis Network (MEAN), characterized by its shallow, multi-stream, and multi-output design tailored for the task of ME analysis. The MEAN architecture consists of three modules: a shared module for extracting lower-level features, a spotting module for identifying the ME intervals, and a recognition module for predicting the emotion classes. To preserve learned knowledge, an Inductive Transfer Learning (ITL) is adopted in the two-step network learning process. Besides, a fairer metric is promoted to measure the efficacy of a complete ME analysis system. The effectiveness is evaluated through qualitative and quantitative assessments on both trimmed and untrimmed video datasets. As one of the pioneering works on multimodal ME datasets, the additional depth information is incorporated to enhance the representations of MEs. Particularly, the scene flow is computed as a feature descriptor to estimate 3D motion changes on the face by leveraging both color and depth modalities. In line with this, the Scene Flow Attention-based Network (SFAMNet) is presented in this thesis. SFAMNet takes the scene flow as input for performing ME spotting, ME recognition, and ME analysis tasks. To facilitate the learning process, data augmentation and end-to-end network optimization are employed. Experimental studies have been conducted to highlight the importance of depth dimension in capturing the subtle temporal changes associated with MEs. Given the limited availability of labeled ME samples, it is hypothesized that Self- Supervised Learning (SSL) can suggest valuable visual cues to the networks by utilizing the self-supervisory signals generated from unlabeled data. Drawing inspiration from the distinct micro-movements phases, a novel SSL pretext task is introduced, allowing the network to learn meaningful spatiotemporal features from unlabeled video sequences. The learned knowledge from this pretext task is then transferred and fine-tuned on several downstream tasks, including ME recognition, ME spotting, as well as Micro-Gesture (MG) recognition. As SSL is still relatively new in the ME domain, some popular pretext tasks are implemented as the baselines for comparison. As a whole, promising results are obtained compared to the existing traditional, SSL, and supervised learning methods, thus demonstrating the effectiveness of the proposed SSL approach
Pemikiran akidah Tuan Minal dalam kitab Aqidah al-Najin: Kajian keselarasannya bagi membentuk Kemahiran Berfikir Aras Tinggi (KBAT) dalam Dokumen Standard Kurikulum dan Pentaksiran (DSKP) / Pauzi Yusoff
No full textPenekanan kepada kemahiran berfikir aras tinggi (KBAT) menjadi fokus utama dalam kemahiran abad ke-21. Sehubungan itu, Kementerian Pendidikan Malaysia (KPM) telah menyediakan Dokumen Standard Kurikulum dan Pentaksiran (DSKP) yang memberi perhatian terhadap aspek pembudayaan berfikir aras tinggi dalam kurikulum akidah. Standard kandungan akidah yang disediakan dalam DSKP adalah ringkas dan ini telah menyebabkan sebahagian pendidik berdepan dengan ketandusan idea sekali gus membantutkan usaha dalam membentuk KBAT. Oleh itu, seorang ulama akidah yang terkenal iaitu Tuan Minal menerusi karyanya ʽAqīdah al-Nājīn telah dipilih sebagai objek kajian bagi meneliti idea-ideanya itu. Objektif kajian ini ialah mengkaji pemikiran akidah Tuan Minal dalam kitab ʽAqīdah al-Nājīn dan mengenal pasti keselarasannya dari segi standard kandungan akidah, menganalisis bentuk-bentuk kemahiran berfikir aras tinggi (KBAT) yang diaplikasinya dalam kitab ʽAqīdah al-Nājīn dan menilai bentuk-bentuk pemikirannya bersandarkan standard kandungan akidah yang dapat membentuk KBAT menurut perspektif Jurulatih Utama (JU) Negeri. Kajian ini berbentuk kualitatif yang melibatkan metode analisis dokumen dan analisis tematik. Bagi mencapai objektif terakhir pengkaji menggunakan perisian Atlas.ti V8 sebagai alat untuk mencari tema-tema yang terdapat dalam pemikiran Tuan Minal berdasarkan standard kandungan akidah. Sehubungan itu, seramai sepuluh orang peserta telah dijadikan persampelan dan ianya dipilih secara rawak menggunakan strategi persampelan variasi maksimum. Dapatan kajian ini menunjukkan terjawabnya persoalan kajian kerana hasil kajian menunjukkan berlaku ketidakselarasan dalam standard kandungan DSKP dengan kitab ʽAqīdah al-Nājīn iaitu dalam tema ketuhanan dan akhlak tetapi mempunyai keselarasan yang tinggi dalam tema kenabian dan perkara al-samʽiyyāt. Punca ketidakselarasan ini adalah disebabkan DSKP yang telah dikemaskini sekarang telah memperbanyakkan tajuk Nama-Nama Allah SWT dan hanya mengekalkan dua tajuk tentang Sifat 20. Ketidakselarasan yang berlaku dalam tema akhlak dan adab juga disebabkan pendekatan dalam DSKP yang lebih terarah kepada usaha memupuk akhlak secara menyeluruh berbanding dengan pendekatan Tuan Minal yang lebih memberi fokus kepada usaha mendidik hati. Dapatan ini juga menunjukkan aras-aras berfikir yang diketengahkan oleh Tuan Minal adalah bersifat anjal dan selari dengan hierarki Taksonomi Bloom. Selain itu, dapatan akhir menunjukkan pemikiran Tuan Minal itu adalah bersifat kritis dan kreatif dan melaluinya ia berupaya mencetuskan idea-idea lain dalam kalangan peserta kajian. Kesimpulannya pemikiran Tuan Minal ini bersifat anjal dan selari dengan KBAT yang menekankan kepada kemahiran berfikir secara kritis dan kreatif. Malah pemikiran beliau ini sangat relevan untuk diaplikasikan dalam DSKP serta boleh dijadikan bahan rujukan dalam pembinaan DSKP pada masa hadapan
An assessment model to evaluate the level of collaborative manufacturing practices for tool and die development in Malaysia / Suman Selvarajoo
No full textIndustrial Revolution 4.0 (IR 4.0) has been getting much interest in many countries including Malaysia. As IR 4.0 looks at the vertical and horizontal integration, some of the key elements are the capacity and capability towards collaborative manufacturing across the manufacturing setup. Understanding the current practices in Malaysia, is important towards strategizing IR 4.0 integration within the Malaysian industries relying on tool and die, which is the focus of this study. The initial step of the research was site observation of manufacturing plants and tool and die fabricators. Followed by host company observation and then for a broader view, an industry survey was conducted involving industry practitioners in the local tool and die industry on the areas that contribute towards tool and die development and the issues surrounding it. This paved the way to understand the condition of the Malaysian industry through the samples which showed poor implementation of collaborative manufacturing. From those findings, a maturity assessment model was developed to evaluate the present state of the collaborative manufacturing of tool and die development of an organisation. The outcome from the literature review, site observation, host company observation, industry survey and C expert feedback provided the basis for the formation of the model which was then defined as Maturity Assessment of Collaborative Manufacturing of Tool and Die Development (MACM - T&D) based on 6 dimensions namely quality collaboration, design collaboration, technology, internal collaboration, management and external collaboration. The model was validated through case studies and anticipated to assist organisations to align their operation towards collaborative manufacturing while modernising their operation to escalate collaborative practices and progress towards IR 4.0. The model recorded positive feedback from the users who agreed with the model outcome and believed it would assist in their future orientation
Wind mapping of Malaysia using ward’s method of clustering and the effect study to lattice structure / Muhamad Amar Azhar
No full textMalaysian media have highlighted the event of strong wind that occurs in multiple
locations in Malaysia. The damage caused by this strong wind has been tremendously
costly to the nation. Malaysian Standard, Code of Practice on Wind Loading for Building
Structure (MS 1553, 2002), was developed in 2002 to predict the highest wind loading in
Malaysia. However, the Code only separates coastal and mainland by using the mean
wind speed. Moreover, due to two monsoons affecting the country, predicting a higher
wind speed period is challenging. However, with the help of the Malaysian Metrological
Department (MET), the collection of the highest wind data was available to be studied
for both Semenanjung Malaysia and Borneo region. Based on the maximum monthly
wind speed capture by 42 MET Station, 30 years of yearly maximum wind speed trend
can be developed to predict the maximum speed in a particular region. Furthermore, due
to the large area of Malaysia, including the Borneo region, clustering of these trends can
further develop a map with a similar maximum speed wind trend. Based on the Malaysian
Standard for wind loading, the Basic Wind Speed (Vs) was based on the basic wind speed
of Semenanjung Malaysia. However, the basic wind speed cannot be expressed as the
maximum wind action towards structures. Therefore, this study suggests with the new
mapping produced, Vs shall be taken as the maximum wind speed with regards to the new
map. The wind speed analysis is then further tested to the three types of lattice structures
where the study focuses on the displacement and highest stress within the structure. This
was achieved by using the 95% confidence interval method to find the mean of the
monthly maximum wind speed. The trend of the maximum wind speed was produced for
30 years where overall finding shows that the highest wind speed trend started from July
until September, and the slowest time of the year is between January and February. The mean maximum wind trend was further analysed by clustering method according to two
main locations of Malaysia, Semenanjung and Borneo. The analysis found that the area
can be clustered into two main groups. The Semenanjung clustering shows that
Semenanjung can be divided into two groups. The first group started from Perlis and
ended at Selangor. The second cluster started at Kelantan and ended in Johor. The Borneo
clustering shows that the coastal area of Sabah and Sarawak can be divided with the
inland. Therefore, the study proposed to use Vs according to the highest wind speed in
the group. The structure analysis also shows a significant increase in deflection of the
structure. The shear analysis also indicates that the most affected member was at the 1st
segment of the structure. The result of this research shows that there is a significant effect
of not adopting the latest highest wind speed during the design. The design parameters
used in the Malaysian Standard are based on the 80’s – 90’s weather conditions.
Therefore, there is a need to update the wind map to minimize the damage due to wind action
Simultaneous extraction of sulfur and nitrogen compounds from model diesel fuel using deep eutectic solvents / Hurun ‘Ein Suhaimi
No full textRemoval of nitrogen and sulfur compounds from diesel fuel is essential to comply with the increasing stringent regulations. Deep Eutectic Solvents (DESs) have garnered attention as promising candidates for this task due to their unique properties, such as low toxicity, tunability, and biodegradability. The primary objective of the study is to address the imperative need for the removal of nitrogen and sulfur compounds from diesel fuel. To achieve this, the study focuses on the extraction capabilities of two selected DESs, namely tetrabutylphosphonium bromide:ethylene glycol (TBPBr/EG, molar ratio 1:2) and tetrabutylammonium bromide:ethylene glycol (TBABr/EG, molar ratio 1:2). The screening of these DESs is conducted via COSMO-RS (Conductor-like Screening Model for Real Solvents), providing crucial insights into their potential performance prior experimental validation of their performance in concurrently extracting sulfur and nitrogen compounds. Two ternary phase diagrams of TBPBr/EG + (pyridine + indoline + DBT) + n-hexadecane and TBABr/EG + (pyridine + indoline + DBT) + n-hexadecane were predicted via COSMO-RS and experimentally validated via liquid-liquid equilibrium at 298.15 K and 1 atm. Compositional analysis by gas chromatography was done and validated via proton nuclear magnetic resonance. The tie lines obtained for both COSMO-RS and experiments were in agreement and has root mean square deviation (RMSD) values of less than 5% for both systems. Selectivity and distribution ratio calculated indicate the suitability of both DESs in extracting sulfur and nitrogen compounds from hexadecane. Two parameters, namely extraction efficiency α and extraction affinity β were introduced to ease the performance comparison of these two solvents. TBPBr/EG shows a slightly better performance than TBABr/EG with α ranging between 77.8% to 89.1 % whereas TBABr:EG has a range between 76.1 to 85.2%. The presence of multiple solutes shows low effects on the performance of these solvents