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Sleep hygiene practice and sleep quality among undergraduate students in School of Health Sciences Universiti Sains Malaysia
(2023-06)
Solihudin, Nurul Izzah
Undergraduate students are commonly vulnerable to suboptimal sleep quality due to increased academic demand. Sleep hygiene is a set of good sleep habits that is believed to be associated with sleep quality. A cross-sectional study was conducted to determine the level of practice of sleep hygiene, the level of sleep quality, and the association between sleep hygiene practice and sleep quality among undergraduate students in School of Health Sciences (SoHS), USM. The questionnaires used in this study were Sleep Hygiene Index (SHI) adopted from Mastin et al., (2006) and Pittsburgh Sleep Quality Index (PSQI) adopted from Buysse et al., (1989). A total of 201 undergraduate students who fulfilled the inclusion were involved in this study. They were selected by a simple random sampling method. Data collected were statistically analyzed by using the Statistical Package Social Science (SPSS) software version 26. This study shows that 116 (57%) respondents had poor sleep hygiene practice level. Meanwhile, 187 (93.0%) respondents have poor quality of sleep. This study also revealed that there is no significant association between sleep hygiene and quality of sleep among undergraduate students in School of Health Science, USM (p=0.243). This study’s finding demonstrated that most undergraduate students in School of Health Sciences USM have poor sleep hygiene and poor quality of sleep. Therefore, sleep education programs as an intervention and prevention strategy are suggested to improve sleep quality and adoption of sleep hygiene practice among students.
System design optimisation of dual thrust solid rocket motor using pso algorithm
(2023-04-01)
Ahmed Mahjub M. Alhaj
So far, chemical rocket propulsion is the only practical means to reach space. Among this rocket propulsion category, Solid Rocket Motor (SRM) placed itself well as the simplest and cheapest propulsion system compared to liquid and hybrid propulsion systems. The design of modern SRMs is a complicated and highly interactive process that involves significant trade-offs between competing objectives such as performance, cost, safety, size, weight, etc. One of these designs is the dualthrust single-chamber SRM (DT-SRM) that is used in several new rocket vehicles. In the literature, the design of DT-SRM has only been treated from the propellant grain perspective ignoring the inherent interaction with other motor design parameters.Moreover, most of these design models were numerical which increased the computational burden. Such approach is limited when implemented on a real-world problem, where all design parameters are affecting each other, and subsequently need to be optimized from a system point of view to give a more efficient and reliable design. Consequently, the ultimate goal of this thesis is to propose, validate, and implement a cost-effective and integrated system design optimisationframework to the preliminary design of DT-SRM based on the main motor design disciplines namely, casing, propellant grain, nozzle, and mass. To satisfy the condition of the dual thrust, an analytical mathematical model for the complex 3-D finocyl propellant grain shape is built and integrated to the other motor design models to form a system design model. The particle swarm optimisation (PSO) algorithm was utilized, with slight modification, in a multidisciplinary design optimisation (MDO) framework to search for the optimum design variables that minimize the total mass of the motor under specified performance and geometrical constraints. The validation results against existing test-firing data confirmed the reliability of the proposed system designoptimisation approach. The proposed approach was successfully implemented in thepreliminary design of a DT-SRM test case, where the performance simulation results of the optimized system showed an improved DT-SRM system design. As a complementary study, the design optimisation results were supported by a flight performance analysis using a six-degrees of freedom (6-DOF) simulation, in which the optimized DT-SRM was capable to deliver a certain payload to a certain distance in a stable flight path. The proposed approach represents an affordable and reliable tool to the preliminary design and optimisation of DT-SRMs intended to serve as a propulsion system for medium-size aerospace vehicles.
Fractal analysis approach in the characterisation of cerebrovascular complexity in asymptomatic cerebral small vessel disease
(2023-02)
Aminuddin, Niferiti
Cerebral small vessel disease (CSVD) refers to a spectrum of clinical and neuroimaging findings caused by pathological damage of small vessels of the cerebral parenchyma. Cerebral white matter hyperintensity (WMH) is one of the commonest neuroimaging findings of CSVD. Often, CSVD is diagnosed once the symptoms developed. Detection of the underlying vascular structural changes might facilitate early disease risk stratification and disease monitoring as vascular alteration precedes cerebral parenchymal injury. Of interest, fractal analysis allows us to quantitatively measure the complexity of the cerebral vascular structure in terms of fractal dimension (Df). The cerebral vascular Df changes are indicative of inefficient tissues perfusion which renders the cerebral parenchyma vulnerable to damage. The aim of this study is to explore a novel vascular neuroimaging marker of asymptomatic CSVD by characterising the complexity of the circle of Willis (CoW) and its tributaries as measured by Df. An exploratory cross-sectional study was conducted involving 22 subjects of age between 25 - 75 years old with low to moderate QRISK2 score who underwent magnetic resonance imaging/angiography (MRI/MRA) examination. These subjects presented with or without WMH. The cerebral vascular complexity of the MRA image was characterised using Df. The cerebral vascular Df was compared between asymptomatic subjects with (WMH+; n = 8) and without cerebral WMH (WMH-; n = 14). Furthermore, cerebral vascular Df was also compared between asymptomatic subjects with both CSVD risk factors and cerebral WMH (RF+ & WMH+; n = 6), subjects with CSVD risk factors only (RF+ & WMH-; n = 5), and subjects without both CSVD risk factors and cerebral WMH (RF- & WMH-; n = 9). Simple linear regression (SLR) was performed between QRISK2 score and cerebral vascular Df. Mean cerebral vascular Df was significantly lower in the WMH+ group than WMH- group. Moreover, the mean cerebral vascular Df of the RF+ & WMH- and RF+ & WMH+ groups were significantly lower than RF- & WMH- group. The SLR model had indicated that increased QRISK2 score significantly predicted reduction in cerebral vascular Df. The cerebral vascular Df was reduced in the subjects with CSVD risk factors and asymptomatic CSVD subjects with WMH. The SLR model had indicated that QRISK2 score significantly predicted cerebral vascular Df. The results indicate that cerebral vascular Df is a promising biomarker of asymptomatic CSVD subjects with WMH. Larger-scaled studies are required to explore its potential in a broader population setting.
Development and validation of the measurement tools and health education module on knowledge and practices for dengue among kindergarten children in Kelantan
(2023-03)
Subramaniam, Neevaarthana
Dengue had been classified as one of the longest existing vector-borne diseases in Malaysia. Community members of all age groups had been prone to dengue infection, however, awareness related studies on dengue among kindergarten children aged five to six years had not been widely explored. Hence, this study aims to assess knowledge and practice levels and test the educational intervention programmes for young children in urban, sub-urban and rural areas of Kelantan. To achieve the objective, this study consisted of a cross-sectional and interventional study design which was conducted in four different phases. In Phase I, a guided interview-based questionnaire with 40 initial items to measure knowledge and practice levels was developed. Flashcards representing the illustration for selected items were also developed. The interview-based questionnaire was then validated and revised through content validity and face validity. The revised interview-based questionnaire was proceeded for item, factor and reliability analysis. The finalised interview-based questionnaire was then pre-tested following a cross-sectional study design among randomly selected 200 kindergarten children. In Phase II, a total of 396 kindergarten children were recruited to obtain knowledge and practice levels using the pre-validated interview-based questionnaire. Next, in Phase III, activity-based and module-based intervention programmes were developed, validated by experts and revised accordingly. In Phase IV, the revised activity and module intervention programmes were proceeded to be tested among 46 and 72 kindergarten children, respectively. Data from all the phases were analysed using the Statistical Package of the Social Sciences (SPSS) according to the respective tests needed to produce the results. For the outcome of this study, the final version of questionnaire consisted of 33 items, with a good internal consistency of Cronbach Alpha of 0.788. Through the measurement of knowledge and practice, practice levels were seen to be significantly higher in both urban and sub-urban areas compared to the rural area (p < 0.05). Significant differences (p < 0.001) were observed in both knowledge and practice scores among participants after implementation of educational intervention programmes. Therefore, this study concludes that the approach using the interview-based questionnaire and the specifically designed educational intervention programmes are effective. They can be considered valid and reliable study instruments for early exposure of dengue knowledge and practices among kindergarten children aged five to six years old.
Removal of arsenic from aqueous solution by various natural soil-based adsorbents
(2023-03)
Fairuz, Farah Shahirah Mohd
Rapid industrialization, mining and agricultural activities lead to the release of contaminants such as arsenic (As) into the water sources that causes adverse effect to living organism. Thus, the application of effective and efficient removal method is crucial. The objective of the study is to apply the adsorption method by utilizing natural soil-based adsorbents including red, clay, sandy and black soil for removal of arsenic from aqueous solution. This study involved the characterisation of heavy metal content and physicochemical characteristic of soil adsorbents, followed by batch adsorption process and the study of adsorption model and mechanism. The results for concentration of arsenic in all soil adsorbents were lower than the permissible limit stated by European United (EU) and mean concentration of iron (Fe) observed to be higher in red soil compared to in other soil samples. For the physicochemical characterisation analysis, red soil has highest number of functional group, content of Fe based minerals, surface area and pore volume with the smallest particle size. From this study, the optimum removal conditions of arsenic from aqueous solution were 2.2 g/50 mL dosage of adsorbents for 60 minutes of contact time at pH of 5.5±0.5 and temperature of 40°C. The adsorption capability and efficiency of soil adsorbent in removing arsenic from aqueous solution were red soil> clay soil> sandy soil> black soil. The kinetic, isotherm and thermodynamic model showed that the mechanism of adsorption of arsenic was a chemisorption, non-spontaneous and endothermic process.