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- Publication3D rock slope stability assessment using anisotropic materials model(2020-10-01)Nagendran, Sharan KumarRock anisotropy is a well-known phenomenon relating to the heterogeneity of rock mass. Nevertheless, its influence in geotechnical design, especially in rock engineering, is often ignored. Slope with certain modes of failure can be evaluated conventionally as well as numerically. For this study, the rock slope assessment was conducted numerically using 2D and 3D Limit Equilibrium Method (LEM) utilizing the Slide program by Rocscience. The fundamental roles of the discontinuities present in the study area were evaluated to study their influence on slope stability. Anisotropic material model was incorporated in the LEM analysis to investigate the presence of discontinuities. The measurement of discontinuity orientation in the rock slope by traditional scanline survey is time-consuming and challenging due to accessibility issues. Structure from motion (SfM) photogrammetry using Unmanned Aerial Vehicle (UAV) allows a quick and cost-effective way to do survey mapping for geotechnical assessment on rock slope compared to terrestrial laser scanner (TLS). Dense point cloud is exported to the CloudCompare tool for geological plane extraction. The stability of the rock slope was evaluated using the deterministic 3D and 2D Limit Equilibrium Method (LEM) using the geometry of the 3D rock slope system. In this study, the anisotropic material model was utilized to examine the Factor of Safety (FoS) results. Generalized anisotropic material model was used for incorporating the Generalized Hoek Brown criterion (rock mass), Mohr Coulomb (weak joint) and Barton Bandis criterion (weak joint). The rock mass and shear strength parameter for numerical analysis were determined via destructive and non-destructive tests such as Uniaxial Compressive Strength (UCS), Schmidt Hardness and JRC estimation using Barton comb. The discontinuities extracted are reliable and accurate as they are within 10° of the data measured manually. By using discontinuity data, the kinematic analysis shows that the rock slope has 12.80% of risk in planar sliding, 6.67% in wedge sliding and 1.93% in flexural toppling. Mean dip / dip direction obtained was used as an input for the value of the anisotropic plane where it causes a weakness in the strength of the rock slope. The results of FoS shows that rock slope without anisotropy model is stable and analysis using anisotropic material model predicts that the slope may fail. 3D slope stability analysis was able to identify the weakest spot easily rather than to assume based on the results of 2D slope stability assessment which might represent the whole rock slope. 3D rock slope stability assessment proves to be very cost-effective method for remedial work whereas in 2D stability assessment, wrong cut-sections may provide inaccurate FoS. This study presents the approach of using anisotropic material model utilizing basic rock testing and field observation data to analyse the rock slope stability.
- PublicationA clinical test for a newly developed direct brain cooling system for the injured brain and pattern of cortical brainwaves in cooling, non-cooling and dead brain(2020)Yee, Ang SongA direct brain cooling system was newly innovated purposedly to ensure direct delivery of therapeutic hypothermia at a selected constant temperature to the injured brain. The practicality, effectiveness and safety of this system were tested clinically in our initial series of fourteen patients with severe head injuries. The patients were randomized into two groups – direct brain cooling at 32°C and the control group. The patients underwent standard decompressive craniectomy. Post operatively, all of them received intracranial pressure, focal brain oxygenation, brain temperature and direct cortical brainwave monitoring. The direct brain cooling group did better in the Extended Glasgow Outcome Scale at the time of discharge and at six months after trauma. This could be due to a trend in the monitored parameters; reduction in intracranial pressure, increment in cerebral perfusion pressure, optimal brainredox regulation, near-normal brain temperature and lessening of epileptic-like brainwave activities are likely reasons for better outcomes in the cooling group. Finally, this manuscript depicts interesting cortical brainwaves during a transition time of being alive to dead. The demonstrated cortical brainwaves are thought as obeying the principles in quantum physics.
- PublicationA retrospective study (2009-2018) on the outcome of uncomplicated twin pregnancies in Hospital Sultan Ismail Johor Bahru : the association between gestational age at delivery and the neonatal outcomes(2020)Nor, Nurliza MdIntroduction: The incidence of twin pregnancy is increasing worldwide1, and so does in Malaysia. It is associated with a higher risk of morbidity and mortality throughout pregnancy to both mother and fetus. This study aims to determine the maternal and fetal characteristic of twin pregnancies in Hospital Sultan Ismail Johor Bahru (HSIJB) and to observe the association between the gestational age at delivery and the delivery outcomes in uncomplicated twin pregnancies. Methodology: This is a retrospective observational study of women with uncomplicated monochorionic and dichorionic twin pregnancies delivered at 36 completed weeks or beyond from January 2009 until December 2018 in HSIJB. The data is divided into 36 weeks group, 37 weeks group, and ≥38 weeks group. The maternal demographic and pregnancy characteristics were observed. The primary outcome was neonatal composite morbidity, which was defined as having one or more of the following: neonatal intensive care unit's admission, low Apgar score, the requirement of mechanical ventilator support, respiratory distress syndrome, and stillbirth or perinatal/ neonatal mortality. The optimal gestational age for delivery according to chorionicity is determine based on the neonatal composite morbidity. Results: A total of 949 sets of twins delivered at HSIJB over ten years, from which 360 women with uncomplicated twin pregnancies and 720 neonatal outcomes were eligible for the study (144 DCDA and 216 MCDA). In DCDA twins, the composite morbidity was least in the 37 weeks group, followed by the ≥ 38 weeks group and then 36 weeks group. On the contrary, more composite morbidity wasseen in the MCDA twinning group at 36 weeks group, followed by the 37 weeks group and later in ≥ 38 weeks group. However, the association between the gestational age at delivery with composite morbidity in MCDA twin were insignificant. Conclusion: Our data suggest that the optimal gestational age for delivery in uncomplicated DCDA twins was at 37 weeks and MCDA twins at ≥38 weeks.
- PublicationA retrospective study on survival analysis and its prognostic factors of prostate cancer patients in Hospital Universiti Sains Malaysia(2020)Lutfi, Ahmad Firdaus AhmadBackground: Prostate cancer is a leading cause of male morbidity and mortality globally and in Malaysia. This study assessed the five-year survival and prognostic factors among prostate cancer patients in Hospital USM, Kelantan. Methodology: We reviewed 150 medical records of patients diagnosed with prostate cancer, from 2009 to 2014. Survival time was analyzed in relation of patient demographics, Gleason score, ASA classification, ECOG scores, PSA level, family history, cancer staging, cancerrelated hematological parameters, and treatment method. Kaplan-Meier survival curves and Cox proportional hazards models are used for the analysis. Results: The prostate cancer five-year survival rate was 84.5%. Overall Kaplan-Meier survival curve showed good median survival times. Univariate regression analysis revealed significant prognostic factors including age (HR=1.06, 95% CI:1.00, 1.11, p=0.034), ASA 3 classification (HR=3.72, 95% CI:1.38, 10.00, p=0.009), ECOG score 2 (HR=17.98, 95% CI:3.98, 81.1, p<0.001), ECOG 3 (HR=33.94, 95% CI:7.41, 150.0, p<0.001), anemia (HR=9.07, 95% CI:3.33, 24.6, p<0.001), High LDH (HR=5.37, 95% CI:1.80, 15.90, p=0.003), High ALP (HR=8.94, 95% CI:3.31, 24.1, p<0.001), Nodular staging (HR=5.87, 95% CI:1.74, 19.85, p=0.004), Metastasis (HR=3.48, 95% CI:1.28, 9.44, p=0.014), Androgen Deprivation Therapy (HR= 0.29, 95% CI:0.08, 0.99, p=0.05) and Chemotherapy (HR=4.57, 95% CI:1.79, 11.6, p=0.001). Conclusion: The five-year survival rate of HUSM patients treated for prostate cancer was 84.5%. The survival rate reduces significantly due to prognostic factors like age, ASA classification, ECOG score, some hematological parameters, cancer staging and chemotherapy. However, patients received the ADT have a better survival rate, which suggests the main role of prompt initiation of the therapy in improving patient survival.
- PublicationA study of punch-die misalignment in square cup deep drawing process using experiment and finite element analysis(2022-09-01)Abdul Ghafar, AlimiSquare deep drawing is a forming process that transforms a flat sheet metal to a seamless vessel by using a set of punch and die. Any misalignment in the punch -die assembly during the process can cause thinning, which can result in the tearing of the drawn part. The onset of thinning due to punch-die misalignment is yet to be explored fully, thus understanding the thinning initiation will be useful for process optimization. In this study, a series of comprehensive methods to identify the presence of punch-die misalignment in square cup deep drawing process is implemented. These methods are deployed at the pre-drawing, during the drawing process and at the post drawing stage. In the pre-drawing stage, an image processing technique is utilized forpre-drawiing inspection. The captured images are analysed to identify the severity of misalignment between the punch and the die. At the second stage (during forming), an in-situ method is used to observe the presence of punch-die misalignment. For this purpose, a customised die rig is fabricated and installed on a universal tensile machine (UTM). A Commercial Electrolytic Zinc-Coated Steel Sheet (SECC) was used as the specimen for the deep drawing process, and the effect of misalignment severity on drawing force and wall thickness distribution are investigated. For comparison, a finite element (FE) simulation is utilized as an early prediction of the punch-die misalignment. The simulation was conducted using Abaqus/Explicit FEA software, utilitising the Hill’48 model, to determine the stress-strain diagram and forming limit diagram (FLD) of the SECC material. Two conditions of misalignment were simulated, 1) single axis punch-die misalignment and 2) multi axes punch-die misalignment with the misalignment severity of 0.1 mm to 0.5 mm. At the post-drawing stage, the wall thickness distributions of the cup for each misalignment conditions were investigated. Variations in wall thickness distributions would indicate the severity of misalignment between the punch and die. Specifically, a novel methods are introduced for detecting the presence of punch-die misalignment in square cup deep drawing process. Both the FE and experimental results were in good agreement with regard to the drawing forces and thinning patterns due to punch-die misalignment. Greater misalignment severity was observed to increase the drawing force and thinning in the wall of the drawn cup. For both misalignment conditions, similar wall thickness distribution patterns were observed, with the maximum thinning occurring in the cup sidewall and minimal thinning at the bottom of the cup. For single axis misalignment, the maximum thickening up to 18% has occured at the lowest misalignment severity of 0.1 mm. On the other hand, for misalignment severity of 0.3 mm and above, the maximum thinning in the x-axis was higher as compared to the y-axis by average of 0.53% and 1.72% based on FE and experimental results, respectively. For multi axes misalignment, the maximum thickening averages at 15%, while the thinning was more pronounced in the rolling direction as compared to the transverse direction. As a conclusion, this study had contribute a positive signification implication in die making, especially punch-die alignment issue in deep drawing process. Alignment punch-die is essential in square cup deep drawing process. A series of comprehensive approach for identifying punch-die misalignment issue according to this study can be referred by researcher and industrial practioner in making high quality square cup deep drawn product.
- PublicationA study on dengue fever presentation and outcome in Hospital Universiti Sains Malaysia(2020)Ismail, Abdullah LutfiDengue fever is one of the most endemic infectious disease in Malaysia and the number of cases increases each year. Patients may present in various phases and forms of dengue, which can progress to severe dengue. The aims of this study were to determine the presentations of dengue infection and factors associated with severe complications. Methods: This retrospective study involved patients aged 12 years and above with positive dengue infection presented to emergency department in our tertiary, suburban hospital and admitted, from year 2016-2018. Patients sociodemographic patterns, presentation and complications of dengue were identified. Factors associated with severe dengue were determined. Results: A total of 327 cases were included, with 66 patients (20.2%) contracted severe dengue. Most common symptoms was loss of appetite (75.2%), followed by fever (65.7%) and vomiting (55.7%). Most common complication was dengue shock syndrome (18.3%) followed by respiratory distress (1.2%). Factors predictive of severe dengue include shortness of breath (AOR 5.82, 95% CI 1.37-24.69, p=0.017), diarrhoea (AOR 0.49, 95% CI 0.27-0.91, p=0.023), tachycardia (AOR 2.85,95% CI 1.59-5.10, p=0.001 and hepatomegaly (AOR 2.76, 95% CI 1.24-6.18, p=0.013). Conclusions: Identifying factors predictive of severe dengue may help physicians in prioritizing the patients care and anticipate deterioration and complications. Factors associated with severe dengue in this study were shortness of breath, diarrhea, tachycardia and hepatomegaly.
- PublicationA study on low temperature synthesis of silicon carbide thermionic cathode and its electron emission analysis for thermionic energy converter(2020-07-01)Leong, Thye JienEnergy conversion of renewable and clean energy such as thermal energy is often related to solar cell and photovoltaic cell. These are the rising technology devices that generate electrical energy for the use in industrial and residential sectors. In order to seek for an alternative approach in meeting the growing energy demand and reducing the dependency on conventional energy resources such as biomass energy, another direct thermal energy to electricity conversion device namely Thermionic Energy Converter (TEC) is being studied. However, the technology involved in this device has one major limitation which is the unavailability of low cost cathode materials with low work function yet easily-obtained. This drawback has motivated the study of cathode material in term of lowering the work function by surface nanostructuring the thermionic cathode for TEC in the mentioned research direction. By using atmospheric pressure chemical vapor deposition (APCVD) method, a low temperature (600°C) synthesis thermionic cathode was developed, as validated by the literature (Xi et al., 2006). In this approach, silicon carbide (SiC) nanostructures were synthesized on the silicon substrate. This method was optimized based on two parameters which are controlling the thickness of catalyst (Magnesium) and the amount of precursors (silicon tetrachloride and 2-ethoxyethanol) used in the experiments. Some material characterization techniques, such as SEM, EDX, and FESEM were performed to the thermionic cathode to support the proposed synthesis method. Besides, a new in-house built TEC system that is equipped with a vacuum chamber, CO2 laser heating system, turbomolecular pump, and digital nanoammeter was developed, which can manipulate temperature of the thermionic cathode. The electron emission analysis of thermionic cathode was performed at different temperature ranges where a copper plate (4.7eV) was used as the anode. Based on the results, a total reduction of ~0.36 eV to the work function of the p-type silicon (111) with ~4.84 eV is achieved by the as-synthesized SiC nanowires thermionic cathode using M200SC3 - ~4.48 eV sample. Lastly, the Schottky effect is proven showing an enhancement to the current density of the SiC nanowires thermionic cathode by compromising a small deviation of the work function of ~0.02 eV. These findings prove that the presence of SiC nanostructures on the thermionic cathode has achieved higher current density, 87 nA cm-2 with the presence of applied voltage at 4000 V/cm and 71.8 nA cm-2 at zero field effect, as compared to 14.4 nA cm-2 for the control sample in this TEC study.
- PublicationAn assessment of optic nerve parameters in Malay normal tension glaucoma and Primary open angle glaucoma patients.(2012)Adlina Abdul RahimThe recent availability of retinal imaging device plays an important role to differentiate the appearance of optic nerve in normal tension glaucoma (NTG) and primary open angle glaucoma (POAG) patients. There no published literature of these two group of glaucoma in patients of Malay ethnicity, or even those who are living in South East Asian areas. To compare optic nerve head parameters among Malay NTG and POAG patients using HR.T III analysis. A comparative cross sectional study was carried out from November 2010 till February 2012 in two hospitals with availability of glaucoma service. A total of 154 eyes of 154 Malay patients were included in this study; 32 NTG patients, 45 POAG patients and 77 control group. All participants underwent a thorough ocular examination including visual acuity, subjective refraction, anterior segment and fundus examinations, Humphrey visual field 24-2, intraocular pressure measurement, gonioscopy examination and fundus photography. An assessment of optic nerve head parameters was conducted using FIRT III by an identified masked investigator in each hospital. Comparison of these two glaucoma groups was further analyzed according to the appearance on cup disc ratio on clinical assessment and AGIS scoring system. Both glaucoma groups had notably larger discs, larger cupping, smaller retinal rims area and thinner nerve fiber layers when compared to the control group (p<0.05). NTG patients revealed larger disc and cup areas when compared to the POAG patients (the mean (SD) for disc area was 2.65 (0.41) mm2 NTG group, and 2.40 (0.36) mm2 in POAG group, p = 0.006; the mean cup area (SD) of NTG patients was 1.54 (0.43) mm2 and 1.32 (0.40) mm2 in POAG group, p = 0.027). This observation was also parallel when they were further analyzed according to the severity of glaucoma in both studied groups. The optic nerve head parameters are significantly different in Malay NTG and POAG patients when compared to healthy individuals. Disc and cup areas are significantly larger in Malay NTG compared to POAG patients, while the other parameters are comparable in both groups
- PublicationAnalysis of brain activation and effective connectivity during self-paced unilateral and bilateral finger tapping using functional magnetic resonance imaging in patients with temporal lobe epilepsy(2021)Yusoff, Bazli MdBackground: Temporal lobe is the most frequent site of origin of partial seizures. Patients with Temporal Lobe Epilepsy (TLE) represent approximately two thirds of the intractable seizure population. Objectives: This study aims to compare the area of activation in between Healthy subjects and Temporal Lobe Epilepsy (TLE) patients as a result of increase in blood oxygen level in different parts of the brain during self-paced unilateral and bilateral finger tapping. In addition, this study also aims to compare the effective connectivity in between region of interest in Healthy subjects and TLE patients during self-paced unilateral and bilateral finger tapping. Methodology: This study involves 12 healthy subjects and 12 TLE patients. All of them undergone functional magnetic resonance imaging (fMRI) where they performed self-paced unilateral and bilateral finger tapping. The images were then pre-processed and undergone first level analysis using Statistical Parametric Mapping (SPM). Second level analysis were then performed to compare the area of activation in Healthy subjects and TLE patients. For effective connectivity, two regions of interest chosen which representing visual and motor region. Three models tested in between each region of interest which are bidirectional, visual to motor and motor to visual. These tests were conducted in each brain hemispheres of both Healthy subjects and TLE patients. Results: In both Healthy subjects and TLE patients, first level analysis showed intense activation at the visual area. Second level analysis was performed comparing the two group of samples, using two samples t-test, FWE p < 0.05, Healthy subjects showed more areas of significant activation. For effective connectivity, two regions of interest were tested, visual area and motor area. Three models were tested, bidirectional, visual to motor, and motor to visual. In healthy subjects, visual to motor was the dominant model with average value of 0.03Hz bilaterally. In TLE subjects, on the right hemisphere, a contrary result was observed whereby motor to visual area was the dominant model. On the left hemisphere, the same model as healthy subjects was the dominant model, visual to motor, but with higher average value of 0.1Hz. Conclusion: This study found that there was less area of brain that has significant activation in TLE patients during motor activity. TLE brains also exhibit different effective connectivity whereby in the right hemisphere, motor area exerts more influence on the visual area and in the left hemisphere, visual area exerts significantly more influence on the motor area. These findings suggest that there is alteration of the motor networks in TLE patients.
- PublicationAnalysis of void formation for no-flow underfill process using numerical simulation and machine learning-based methods(2022-09-01)Nashrudin, Muhammad NaqibThe no-flow underfill process has been developed as an alternative to the conventional capillary flow underfill. It offers low cost and lead time production effectively due to the integration of simultaneous reflow of solder interconnect and cure of underfill material. Somehow, no-flow underfill also faces the same reliability issue which is the potential void formation during the process. The research on the void formation issue in no-flow underfill has been found scarce. In addition, the research works on no-flow underfill focused on the experimental method which is costly and very limited to study the root cause of the issue. Therefore, this research presents a numerical simulation study of the no-flow underfill which has the ability to track dynamically the movement of the flow of underfill in real time during the process. This research investigates and predicts the possible void formation of no-flow underfill. Three major parameters were selected to align with industry requirements which are chip placement speed, bump pitches and viscosity of underfill. Subsequently, previous literature of no-flow underfill experiment, industrial no-flow underfill experiment and current scaled-up imitated flip-chip experiment were compared in term of flow and void formation percentage to validate with the current numerical simulation. Overall, the current numerical simulation produced low discrepancy which is less than 15% error among all the experiments and affirmed the capability and accuracy of the numerical simulation model. It was found that the void formation rate increases with the chip placement speed but decreases with the increase in bump pitch. The highest chip placement speed of 14 mm/s produces 4-6% meanwhile, the low chip placement speed (2-5 mm/s) produces around 2-3.5% of void formation. Moreover, several supervised machine learning prediction-based methods such as linear regression, decision forest regression and neural network regression were implemented to train the numerical values and to investigate further the most significant parameter that affects the void formation in the chip. It is observed that linear regression, decision forest regression and neural network regression produced mean absolute errors between 0.1588, 0.176375, and 0.1818, respectively. The neural network regression is the preferred algorithm method of machine learning in the study since it shows the least error with a high R2 value of 0.95159. Based on permutation feature importance, the most significant parameter that affect the formation of void in the no-flow underfill was chip placement speed compared to bump pitches and underfill’s viscosity with a score of 1.7916, 0.2962 and 0.000878, respectively. This research provided engineers in the microelectronic industry with a deep understanding of the void formation and expected to provide an appropriate guide to minimize the failure for the development of no-flow underfill in the future.
- PublicationAnthropometric profiling of state level sepak takraw players(2016-06)Jamaluddin, Mohamad AnuarINTRODUCTION: Data of anthropometric measurement are important for talent identification and developmental program. To date, the profile of anthropometric components among state level sepak tak.raw players have been scarce. Thus, this study was carried out to provide data on anthropometric components of sepak tak.raw players for age under 15 and 18 year old especially at the state (developmental) level. PURPOSE: This study was carried out to access the anthropometric profile and body type of state level sepak tak.raw players. METHOD: Fifty four males participants (n = 54) participated in this study, who originated from Penang (n = 30) and Kelantan (n = 24 ). All participants were currently playing at state level and age ranging from 13 to 18 years old. The participants were measured for their standing and sitting height, weight, skinfold measurement (i .e. 8 sites skinfold), girth (i.e. calf and arm flexed with tensed) and breadth (i.e. humerus and femur) . RESULT: The result represented the participants' anthropometric data of the standing height, body weight, sitting height, percentage of body fat and somatotype value. The tallest between all three positions in under 15 category was server 165.57 ± 9.05 em. Under 18 category, the tallest player was the killer 168.31 ± 5.94 em. The total mean of BMI for all three positions for under 15 category was 19.43 ± 2.70 kgm-2 and 21.40 ± 2.45 kgm-2 for under 18 category respectively. The highest measure for sitting height between all three positions in under 15 and under 18 category was the server (85.56 ± 4.83 em) and (87.64 ± 3.02 em). The highest mean percentage of body fat for under 15 category was the server (6.53 ± 3.15 %) while the lowest value was the killer (4.45 ± 1.54 %). Meanwhile, the highest mean percentage of body fat for under 18 category players was the server (6.52 ± 3.51 %). Then, the lowest value was the killer (5 .15 ± 3.14 %). Finally, for somatotype, the total mean of somatotype value for players under 15 category was 2.3-4.4-3.2 which is refer to as ectomorphic-mesomorph category. In addition, the total mean of somatotype value for players under 18 category was 2.2-5-2 .8 which is refer to as ectomorphicmesomorph category. CONCLUSION: The measurement of the anthropometric and somatotype value of state level sepak takraw players showed different body physique and body composition among all three positions. Since there were limited data in previous study, thus, results of this study will provide new information and contribute to the athletes ' performance and selection of athletes in sepak takraw.
- PublicationApplication of tin (IV) tetrachloride and jatropha curcas in coagulation-flocculation process for the treatment of stabilised landfill leachate(2021-11-01)Syed Zainal, Sharifah Farah FarizaLeachate is one of the most common problems faced by landfilling methods that can jeopardize the life and environment due to the excessive concentrations of pollutants. It must be treated first before discharge into the environment. The coagulation-flocculation (C-F) process has been extensively used in landfill leachate treatment. However, leachate needs high strength coagulant to remove higher pollutants. The application of tetravalent metal salts coagulant in combination with a natural coagulant and the effectiveness of tetravalent metal salts in a C–F process is still inclusive. This study was performed to determine the best C-F operational conditions such as pH and coagulant/flocculant dosage, rapid mixing, slow mixing, and settling on the removal of chemical oxygen demand (COD), colour, and suspended solids (SS) in a stabilised leachate from Alor Pongsu landfill site, Kerian, Perak as a case study site. Tin (IV) Chloride (SnCl4) and Jatropha curcas (JC) seed or ‘buah jarak’ was tested as a sole coagulant and later mixed with JC reacted as a flocculant. A series of jar tests were conducted, and the C-F mix was optimised using response surface methodology (RSM) and central composite design (CCD). Floc’s size and sludge properties were also evaluated, followed by an acute toxicity test on the raw and treated effluent. Excellent removals of 99.5 %, 98.4 %, and 71.5 % for SS, colour, and COD, respectively, were obtained by using 11.1 g/L of SnCl4 as coagulant alone at pH 8. JC seed was poor as a sole coagulant with only 33.9 % and 23 % reductions in colour and COD, respectively, with no removal in SS. However, with the combination of SnCl4 as a coagulant and 0.9 g/L of JC seed as a flocculant, the SnCl4 dose was reduced to xxiv 8.5 g/L with 99.8 %, 98.5 %, and 74.3 % reductions in SS, colour, and COD, respectively. The sludge and floc characteristics tested showed that JC helped in producing larger flocs, increasing the sludge velocity, and having a higher flocculation index. The treated sample with SnCl4 as coagulant and JC as a flocculant could reduce the toxicity effects to tested Tilapia fish and is safe to be discharged at appropriate dilution concentrations. It can be concluded that JC seeds have the potential to be applied as a natural flocculant with SnCl4 as the main coagulant in the treatment of leachate. This could reduce the dose of the inorganic commercial coagulants currently in use with better sludge properties.
- PublicationAssessing sustainability index of water resources system for lombok river basin(2022-05-01)Wit Saputra, Anggara WiyonoRiver basin sustainability is vital for the fulfilment of water demands, but the majority of river basins worldwide, including those in Indonesia, are increasingly being severely degraded, leading to their unsustainability. The Lombok river basin at Nusa Tenggara Barat province, Indonesia, is currently experiencing such problems. Water balance in the Lombok river basin is closely affected by climate conditions, which in turn affects the availability of water. In addition, the basin is experiencing shrinking reservoir storage due to sedimentation, deterioration of river headworks structure, and irrigation efficiency reduction, all of which have a reverse effect on maintaining the sustainability of the water resources system. This study focuses on the Lombok river basin, which experiences unique climate characteristics and conditions in variability which has generally affected water availability and its distribution. Interbasin transfer conveys water from the western area, which has surplus water, to the central and eastern parts of the river basin. This study aims to assess the water resources system sustainability in light of the availability of streamflow and fulfilment of water demand in the Lombok river basin to provide information for the stakeholders and decision-makers. The methodology includes simulation and optimization of the water resources system to assess the water resource system performance indicators (reliability, resilience, and vulnerability) and sustainability index for various system improvement scenarios. The SWAT model was employed to simulate the Lombok streamflow with the corresponding land use and soil map data based on historical data as the required inputs. Calibration and validation processes using SUFI-2 were done to get the appropriate parameters used in SWAT model. By applying simulated streamflow as an input, the MODSIM model was used to simulate and optimize water allocation in the system to predict performance indicators at each headwork for irrigation and domestic demand. The results show that the smallest watershed sustainability index for irrigation was in the Renggung watershed and the Palung watershed was the smallest domestic watershed sustainability. The results show that the smallest watershed sustainability index for irrigation was in the Renggung watershed at 0.188 in 2017-2025, which decreased to 0.177 in the climate change period (2032-2040). Babak watershed was the smallest domestic watershed sustainability index at 0.884 and down to 0.812 in the climate change period. Watershed index with the same weight of 0.50 for domestic and irrigation demand, respectively, showed the highest was Jangkok watershed followed by Dodokan, Meninting-Midang, Renggung, Babak, Palung, Rere Penembem, and Pare Ganti. Results from this study indicated that the operation of the new dams and improvement of irrigation efficiency enhanced the water sustainability index at most simulation scenarios. These results indicate that careful constructing of suitable new dams and improvement of irrigation efficiency is justified in the Lombok river basin as they contribute towards the enhancement of water sustainability in the river basin.
- PublicationAssessment of electric arc furnace slag as soil stabilizer and fertilizer for mangrove seedling(2022-02-01)Kong, Ern HunSlag from Electric Arc Furnace (EAF) is generated from steelmaking processes, and it is the most in term of volume among the by-products. Production practices and processes, and the skill of operator are among the factors that will cause significant variation in chemical and mineralogical properties. Successful recycling of the slags depends on understanding the differences and how the properties can be exploited. This project aims to evaluate each of the slags and explore their potential use in agriculture as soil modifier and nutrients source. Three slag samples of NL (normal production CaO saturated slag), HM (MgO saturated slag) and HF (high Fe slag), which were taken from different points in production and practices were characterized. The experimental works were carried out purely on the raw slag from production. It was crushed, ground, and sieved into three sizes of 0.15 – 0.25 mm, 0.25 – 0.50 mm and 0.5 – 1.0 mm. The slags were characterized by chemical, mineralogical and leaching study, and then evaluated for their effects to the growth rate of mangrove seedlings in field study. Preliminary study of leaching test and consideration of environment in field study were carried out to set the parameters for field works. Leaching test was carried out to confirm the leached elements meeting the environmental regulation standard and nutrient required by mangrove seedlings. Parameters for leaching test are different pH values (distilled water 6.8, rainwater 5.78 and seawater 8.37), stirring speed (350 and 700 rpm), and duration up to 16 weeks. Meanwhile, the field study was carried out with soil from mangrove forest and nursery center, treated with the three types of EAF C slag. The result of leaching test has confirmed the maximum level of 15.8 µg/L Cr (VI) is still far below the control limit of 50 µg/L in DOE requirement in Standard B Limit as per Malaysia Environmental Quality (Industrial Effluents) Regulations 2009 and WHO advisory Cr (VI) control limit for drinking water. Meanwhile, maximum 49.7 mg/L of Si, 45.7 mg/L of Ca, 0.581 mg/L of Fe, and 19.9 mg/L of Mg obtained from elemental leaching test has confirmed the availability of elements as nutrients for mangrove seedlings. As disturbed muddy soil in mangrove forest from natural disaster or human activities would lead to formation of sulphate, creating acidic condition soil which will affect the mangrove growth, alkaline slag could be used to neutralize the soil and improve growth. Slag NL with highest alkalinity of pH value 11, capable to increase the pH value of acidic soil from 3.65 to 8.5, which provides suitable condition for nutrients uptake for seedlings. The field study showed that not all the nutrients uptake by seedlings can be correlated with chemical content in slags, but seedlings treated with slags did achieve higher growth rate compared with seedlings without treatment, especially the stem height and seedling leaf area. Magnesium saturated slag with > 8% MgO and oxidized slag with > 35 % FeO is suitable for acidic muddy soil as they would enhance the leaf growth of seedlings. The highest leaf generation rate of 195.3 mm2/day, was achieved by seedling in soil MF treated with slag HF which contain 39.9 % of FeO compared with 164 mm2/day of leaf area generation in seedlings without slag treatment. The highest stalk growth rate of 3.73 mm/day was achieved by seedlings in soil NC treated with slag HM which contain 11.4 % MgO compared with 2.77 mm/day in seedlings without slag treatment. Based on this study, EAF C slag has great potential as soil modifier and nutrients source for mangrove seedlings in nursery center, and this re-use of slags is safe and would not leach out harmful elements into the environment.
- PublicationAssessment of inflammatory markers and periodontal outcomes in CKD patients with periodontitis(2022-06)Rahman, Nurul Aliya AbdulChronic kidney disease (CKD) and periodontitis have an impact on patient’s morbidity and mortality. The prevalence of comorbid CKD and periodontitis is shown to be frequent. Periodontitis increases the inflammatory burden, which has been shown to disrupt renal function by altering serum inflammatory levels, and potentially worsening CKD. Pro-inflammatory Interleukin-1 (IL-1) and anti-inflammatory Interleukin-10 (IL-10) have immunomodulatory properties that regulates host immune responses. Little is known about changes in the serum inflammatory markers of IL-1 and IL-10 following the periodontal therapy in CKD patients in our populations. Therefore, this study was aimed to assess and compare the levels of inflammatory markers IL-1 and IL-10 as well as periodontal parameters at baseline and after receiving NSPT. Twenty CKD patients (stage 3 and stage 4) with periodontitis (Group 1), twenty non-CKD patients with periodontitis (Group 2) and twenty healthy patients (Group 3) were selected. The dental parameters such as Periodontal Probing Depth (PPD), Clinical Attachment Loss (CAL), Gingival Bleeding Index (GI) and Plaque Score (PS) were measured in each patient during first visit (baseline) and six weeks later (second visit). Blood sample was collected during each visit and analysed for serum IL-1 and IL-10 concentration using Enzyme-Linked Immunosorbent Assay. Our findings shows that IL-1 and IL-10 levels were found significantly higher (p<0.05) in CKD patients with periodontitis (Group 1) as compared to non-CKD patients with periodontitis (Group 2) and healthy subjects (Group 3). When compared to other groups, the levels of dental parameters (PPD, PS and GBI in Group 1 were significantly higher (p<0.05). Following NSPT, there was significant reduction (p<0.05) in inflammatory markers and clinical periodontal parameters in Group 1 and Group 2. This study demonstrates that patients with CKD and periodontitis had a more severe systemic inflammatory response and poorer periodontal status than non-CKD. NSPT shown improvement in both inflammatory markers and dental parameters as well as delay the progression of CKD. IL-1 and IL-10 is a promising inflammatory marker to assess CKD progression. Therefore, multicentre and larger sample size studies are needed in the future.
- PublicationAssociation of genetic polymorphisms and their attributing factors with lipid profiles among outpatient statin users in Hospital USM(2022-07)Shamsudin, Amirul FaezStatins, or 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, are routinely used to lower lipid levels primarily low-density lipoprotein cholesterol (LDL-c). Treatment guidelines recommend LDL-c as the primary target of therapy in hyperlipidaemic patients. Inter-individual variation in LDL-c-lowering efficacy and side effects of statins are due to genetic polymorphisms and environmental factors. However, pharmacogenetics studies on the effects of the aforementioned factors on the lipid profiles of statin users in Malaysia are still lacking. We evaluated the association of patient’s genetic polymorphisms, demographic profiles, and clinical factors with lipid profiles among outpatient statin users from Hospital Universiti Sains Malaysia (HUSM). In a cross-sectional retrospective study, a total of 229 hyperlipidaemic statin users were recruited and the patients' genotypes for eight single nucleotide polymorphisms (SNPs) in seven candidate genes were determined using the polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method and validated by sequencing analysis. Using a dominant genetic model, an independent t-test was used to compare total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), LDL-c and triglycerides (TG), and the results with significant differences were stratified according to gender. A multiple binary logistic regression model was conducted, with LDL-c < 2.6 mmol/L at the endpoint serving as the dependent variable while other explanatory factors as independent variables. Minor allele frequency (MAF) of the studied SNPs as follow; CETP rs708272 = 0.39, ABCG2 rs2231142 = 0.12, ABCC2 rs717620= 0.58, APOE E4 = 0.35, GATM rs9806699 = 0.63, COQ2 rs4693075= 0.96, and APOA5 rs662799= 0.45. Only CETP rs708272 and COQ2 rs4693075 were matched to the MAF of the reference population (i.e., East Asian populations) obtained from the ENSEMBLE database (P>0.05). Of all SNPs genotyped, two SNPs (CETP rs708272 and ABCG2 rs2231142) were associated with baseline lipid parameters. At the baseline before statin treatment, female minor allele carriers of CETP rs708272 were associated with higher LDL-c (4.02 ± 1.44 mmol/L vs 3.44 ± 0.84 mmol/L, P=0.007) and lower TG levels (1.52 ± 0.63 mmol/L vs 1.90 ± 0.98 mmol/L, P=0.044). ABCG2 rs2231142 was associated with higher HDL-c levels in both overall (1.38 ± 0.37 mmol/L vs 1.25 ± 0.26 mmol/L, P=0.035) and females group (1.49 ± 0.38 mmol/L vs 1.33 ± 0.27 mmol/L, P=0.047). After the initiation of statin treatment, two SNPs (ABCC2 rs717620 and APOA5 rs662799) were associated with anti-atherogenic effects. In particular, ABCC2 rs717620 was associated with significant reduction of TG levels in the overall (1.48 ± 0.75 mmol/L vs 2.17 ± 1.14 mmol/L, P=0.009) and males group (1.48 ± 0.85 mmol/L vs 2.40 ±0.91 mmol/L, P=0.006). Similarly in males, minor allele carriers of APOA5 rs662799 resulted in higher HDL-c (1.20 ± 0.25 mmol/L vs 1.07 ± 0.15 mmol/L, P=0.006) and lower TG levels (1.42 ± 0.81 mmol/L vs 1.69 ± 0.75 mmol/L, P=0.038). In the multiple binary logistic regression analysis, only pravastatin users independently predicted patient’s achieving LDL-target of <2.6 mmol/L (P=0.040, OR=0.110). In conclusion, CETP rs708272 and ABCG2 rs2231142 determined the baseline lipid differences in females, whereas ABCC2 rs717620 and APOA5 rs662799 determined the lipid differences after statin initiation in males group.
- PublicationBio-based and hybrid based polymer composites for enclosures of memory storage device application(2022-08-01)Janakiraman, Vishnu ChandarA large proportion of consumer electrical and electronic packaging applications were made up of thermoplastics. Casings or enclosures are generally used in circuit boards, and data storage which is made up of plastic to ensure the appliances are mobile, lightweight while being tough and durable and at the same time, the plastics used in these applications are very high and also not biodegradable. This research aims to reduce the usage of plastics in storage applications via two approaches, i.e., bio-based and hybrid-based polymer composites. In this work, pure polymer [polylactic acid (PLA), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), cellulose acetate (CA)] and its bio-based composite ((PLA/Aluminium oxide (Al2O3)/Boron Nitride (BN)), PLA/BN/Graphene tubes (GT), PHBV/Al2O3/BN, PHBV/BN/GT, CA/Al2O3/BN, CA/BN/GT) sheets with different concentration of hybrid filler [(Aluminium oxide (Al2O3)/Boron nitride (BN), BN/Graphene tubes (GT)] were fabricated. Similarly, pure thermoplastics (polyoxymethylene (POM), polypropylene(PP), polycarbonate (PC)) and its hybrid-based composite POM/PHBV/Al2O3/BN, POM/PHBV/BN/GT, PP/cellulose fiber (CF)/Al2O3/BN, PP/CF/BN/GT, PC/basalt fiber (BF)/Al2O3/BN, PC/BF/BN/GT) sheets with different concentration of hybrid fillers were fabricated using internal mixer equipment and compression molding method. The effect of fillers on the structural, optical, thermal, thermophysical, mechanical, surface, electrical properties of the pure polymer and its bio-based and hybrid-based polymer composite sheets were studied, compared, and suggested for electronic packaging applications. XRD results confirm the presence of polymers and fillers (ceramic, carbon, and natural) in the prepared bio-based and hybrid-based composites. The prepared bio-based (PLA/BN/GT, PHBV/BN/GT, CA/BN/GT) and hybrid-based (POM/PHBV/BN/GT, PP/CF/BN/GT, PC/BF/BN/GT) polymer composites exhibit high UV-VIS-NIR absorption, thermal conductivity (0.29 - 0.51 W/mK and 0.35 – 0.53 W/mK), flexural strength (34.2 – 66.4 MPa and 59.1 –74.8 MPa), flexural modulus (1088 – 3239 MPa and 1313 – 3424 MPa), storage modulus (726 – 2130 MPa and 1492 – 3132 MPa), scratch hardness (0.43 – 0.73 GPa and 0.44 – 1.19 GPa), and low CTE (17 - 42.9 µm/m ºC and 38.6 – 114 µm/m ºC), ESD (<10V to <100V and <10V) compared to composites with Al2O3/BN filler and pure polymer that may be due to the high thermal conductivity, mechanical strength and synergetic effect of BN and GT filler. As for dielectric permittivity, Al2O3/BN reinforced composites exhibit favourable dielectric constant (3.02 - 4.74 and 2.72 –3.37) and loss (< 0.02), whereas BN/GT reinforced polymer composites shows higher values at a lower frequency. Like bio-based, hybrid-based polymer composites also follows the same trend in dielectric permittivity. On comparing the bio-based composites, CA/BN/GT polymer composites are suitable for USB products with high storage capacity as per the obtained melting, glass transition temperature, CTE, ESD, mechanical, and scratch performance, whereas PLA/BN/GT and PHBV/BN/GT polymer composites are suitable for USB products with very low storage capacity and can ultimately reduce 98% of plastics. Similarly, the prepared hybrid-based polymer composites (POM/PHBV, PP/CF, PC/BF) with BN/GT filler are suitable for USB, SSD, and HDD products with both low and high capacity as per the obtained thermal, ESD, mechanical, and scratch performance and can ultimately reduce 15-40% of plastics in enclosure applications.
- PublicationBioactive glass-cordierite ceramics for biomaterials application(2022-06-01)Mohd Mokhtar, Ahmad Kamil FakhruddinBioactive glass (BG) is one of the biomaterials that are widely used in various biomedical applications such as dental implant, due to its excellent ability to bind with tissue through a bonding formation with apatite layer. However, BG demonstrated low mechanical strength to withstand external force. In this study, bioactive glass-cordierite ceramic (BG-cord) composite was developed to overcome this issue. BG and cordierite were synthesized using glass melting method prior to BG-cord fabrication in pellet shape. In the fabrication process, the milling time of cordierite (0.5 to 5 h), the composition of BG and cordierite, and the sintering temperature of BG-cord (600 – 1000 ºC) were studied. An improvement in the mechanical properties of BG was observed with the addition of cordierite, proven by the superior diametral tensile strength (DTS) of BG-cord to BG. The DTS of BG increased from 6.29 MPa to 14.01 MPa upon milling with 30% cordierite for 3 hours. A further increase in DTS value from 14.01 MPa to 30.54 MPa was recorded when the BG-cord was sintered from 600 °C to 925 °C. The optimum BG-cord exhibited physical characteristics of 2.33 g/cm3 bulk density, 8.92% porosity, 30.54 MPa DTS, 93.75 MPa compressive strength, and 153.93 Hv hardness. A positive response of bioactivity performance was observed in the BG-cord with apatite formation as detailed in the in-vitro analysis using scanning electron microscope (SEM). X-ray diffraction (XRD) analysis revealed apatite peaks proved the formation of apatite. The increase of intensity of P-O and C-O spectra from Fourier transform infrared (FTIR) analysis after bioactivity test also proved the apatite formation. As a conclusion, the BG-cord produced from the current study has potential application as a dental implant material.
- PublicationBiodegradation of natural rubber latex films filled metroxylon sagu pith waste by immobilised bacillus cereus(2020-09-01)Adzami, Nuraiffa SyazwiThe accumulation of NR gloves for biodegradation is occurred continuously at the disposal site due to the slow biodegradation process. The incorporation of treated sago pith waste (TSPW) in natural rubber (NR) latex films were prepared to enhance the biodegradability of the films. Bleaching treatment and ball milling were carried out to treat the TSPW as filler for NR latex films. The rubber-degrading bacteria is identified to monitor the biodegradation of films. Two types of system with freely suspended bacteria and immobilised bacteria through batch study were studied and the culture conditions were optimised. It was found that TSPW filled NR latex films showed optimum mechanical properties and good colloidal stability of the NR compound. Tensile strength and tear strength were recorded as 23.83 MPa and 63.87 N/mm. Bacillus cereus ATCC 14579 (B. cereus) is identified to utilize these films as the sole carbon and energy sources. Granular activated carbon (GAC) is used as adsorbent to adsorb B. cereus. This system called B. cereus-GAC system followed Freundlich isotherm and Pseudo-second-order kinetic model. In 14 days of biodegradation, both systems show significant weight loss and mechanical properties reduction of TSPW filled NR latex films as compared to unfilled NR latex films. Thus, TSPW filled NR latex films and B. cereus have the potency to provide a biotechnological solution to the waste NR gloves disposal problem.
- PublicationBrain activation changes during positive and neutral emotion regulation task following brief mindfulness: an fMRI study(2022-05)Balakrishnan, Dhiviya GopalIntroduction: Mindfulness is used to bring awareness and focus to a present state of mind. It also enhances positive emotion where people with a mindfulness state have control of their emotion and reduces the regulation of negative emotion. Objective: This study focuses to identify the associated brain activation of positive and neutral emotion regulation task following brief mindfulness exercises. Methodology: This study focuses on the healthy and young adult population. A neurotechnology tool is used which is functional magnetic resonance imaging (fMRI) to identify the brain activation of positive and neutral emotions. The positive and neutral emotion regulation task which was measured during the pre and post task consisted of positive word and neutral word stimuli which are extracted from Affective Norms for English Words (ANEW). Mindfulness state is assessed using the Mindful Attention Awareness Scale (MAAS) and the affect of the positive emotion regulation task is assessed using the Positive Affect and Negative Affect Scale – Expanded (PANAS-X). Results: Six participants were included in this study. The mindfulness group for positive emotion showed activation in the inferior frontal operculum, tri – inferior frontal, superior frontal and calcarine, while the neutral emotion showed activation in Rolandic operculum, postcentral gyri, calcarine and precentral gyri. The response time for both groups was insignificant (p > 0.05) but displayed a large size effect over the post-task. The positive effect for both groups was insignificant (p > Introduction: Mindfulness is used to bring awareness and focus to a present state of mind. It also enhances positive emotion where people with a mindfulness state have control of their emotion and reduces the regulation of negative emotion. Objective: This study focuses to identify the associated brain activation of positive and neutral emotion regulation task following brief mindfulness exercises. Methodology: This study focuses on the healthy and young adult population. A neurotechnology tool is used which is functional magnetic resonance imaging (fMRI) to identify the brain activation of positive and neutral emotions. The positive and neutral emotion regulation task which was measured during the pre and post task consisted of positive word and neutral word stimuli which are extracted from Affective Norms for English Words (ANEW). Mindfulness state is assessed using the Mindful Attention Awareness Scale (MAAS) and the affect of the positive emotion regulation task is assessed using the Positive Affect and Negative Affect Scale – Expanded (PANAS-X). Results: Six participants were included in this study. The mindfulness group for positive emotion showed activation in the inferior frontal operculum, tri – inferior frontal, superior frontal and calcarine, while the neutral emotion showed activation in Rolandic operculum, postcentral gyri, calcarine and precentral gyri. The response time for both groups was insignificant (p > 0.05) but displayed a large size effect over the post-task. The positive effect for both groups was insignificant (p > 0.05) but the audiobook group, showed a medium size effect while the mindfulness group showed a large size effect in the positive affect of PANAS – X. Conclusion: Visual, motor, and language had higher activation which would be defined by the presence of the audiobook and mindfulness audio and word stimuli while the mindfulness audio group showed a slight regulation of positive emotion. The small sample size showed the reduced efficiency of the results, but the large effect size indicated that differences in response time and positive effects are worth to be conducted in future studies. The study is suggested to be expanded to all age groups. In this preliminary study, a brief mindfulness exercise with 15 minutes time frame was able to identify the emotional effect on an individual.