13474 research outputs found
Sort by
A case study of ownership and use of air conditioning in a tropical urban area and its impact on energy consumption / Shit Mun Chuan
No full textMalaysia, a tropical country had experienced a drastic increase of air conditioner ownership in the past few decades, data from market demand also suggest that the growth would maintain an upward trend in the future. This study aims to review on the trend of households’ ownership of air conditioners (AC) and the energy consumption of AC in residential and non-residential area. The selected area of study is Petaling Jaya, a tropical urban environment. Due to the rejection of waste heat from the air conditioner cooling process, it is suggested that there would be an increase in outdoor temperature where air conditioner is in used. This rise of temperature causes a higher average temperature in the urban area. Additionally, it is suggested that this will also increases the usage of air conditioning to maintain the thermal comfort of the indoor environment. This study also recommended alternative cooling methods in an urban area such as a building structure design, ventilation, increase vegetation, green roof and cool roof was recommended
Experimental analysis of indoor air quality for human comfort in vehicle cabin / Siti Nor' Ain Mokhtar
No full textIn present time more people spend a relatively longer time inside their vehicles. However, the microenvironment of a vehicle cabin is vulnerable to exposure of air contaminants such as carbon dioxide, Carbon Dioxide (CO2) and Particulate Matter PM10 originated from the surrounding and vehicle operation. Carbon Dioxide would cause acidosis, which is particularly harmful to the cells of the brain. Even at low-to-moderate, CO2 (>800ppm) has been found to be associated with headache, fatigue, kidney failure and reduce cognitive ability in humans. Exposure to Particulate Matter10 affects the lungs and heart, leading to health complication such as nonfatal heart attacks, irregular heartbeat, aggravated asthma, decreased lung function, and increased respiratory symptoms. The purpose of this study is to assess and analyze the indoor air quality Indoor Air Quality (IAQ) of a car travelling the route between UTeM main campus and FTK campus. This experiment was conducted for Perodua Myvi and Honda Freed for 2 condition of time there is morning and evening. The assessment was conducted in a car as it was travelling along the designated route. Total route of 2 destination are16km. The 3M EVM (Environmental Monitor) was set up to measure the parameters such as temperature, carbon dioxide (CO2), and particulate matter (PM10). Additionally, the study regarding the number of passengers and vehicle operation (driving/idling) was also done. The average temperature for Perodua Myvi during morning was 26.9°C, while 27.0°C for evening which staying within the DOSH acceptable range, 26-27.0°C. Whereas the average temperature for Honda Freed during morning and evening was 27.3°C and 27.5°C respectively which exceed than Department of Safety and Health (OSH) acceptable range. The overall mean of CO2 concentration for Perodua Myvi during morning for 2 and 5 passengers are 276 and 291 respectively. While during evening are 114 and 196 respectively. Honda Freed is gradually increase during evening up to 627 for 5 passengers compared with Perodua Myvi. In term of Particulate Matter, the experimental data for both cars during morning and evening are within acceptable range of 150μg/m3 from United States Environmental Protection Agency (USEPA)
Study on engine performance and exhaust pollutant using isobutanol - Calophyllum inophyllum biodiesel - diesel ternary blends in a diesel engine / Mohd Azham Mohd Alwi
No full textRenewable energy sources such as biodiesel and bio-alcohol are desirable and are alternative to meet energy demand and control emission, from renewable sources such as ethanol, methanol, butanol, and pentanol. Biodiesel has a notable interest in offering many advantages with few disadvantages and needs to be extended for comprehensive use. Applying greater alcohols such as butanol with biodiesel in fuel blends is a beneficial technic to enhance the fuel characteristics and use biodiesel and alcohol efficiently. Isobutanol is an organic compound that has very low volatility, higher-chain alcohols have energy densities close to gasoline. It is not as volatile or corrosive as ethanol and does not readily absorb water. Furthermore, branched chain of alcohols such as isobutanol have higher-octane numbers resulting in less knocking in engines. The molecule has nearly 20 percent higher energy density compared to ethanol. The chemical structure and its production from renewable sources can enhance energy security and environmental challenges. To assess the suitability of isobutanol with biodiesel diesel blends and reveal the effects of it, 5%, 10% and 15% of isobutanol were blended with 5%, 10% and 15% of Calophyllum inophyllum biodiesel to enhance the fuel features and make them more viable with better engine efficiency. The experiment was carried out under distinct load circumstances on a single-cylinder compression ignition diesel engine, four-stroke, water-cooled, direct injection diesel engine, 1.97 bar to 7.88 bar brake mean effective pressure (BMEP). The fuel characteristics, engine efficiency, and exhaust pollutants were assessed and compared to biodiesel blends and diesel from petroleum. From the experiment, it is been discovered that the diesel engine operating with higher alcohol-biodiesel blended fuels has shown higher brake specific energy consumption and exhaust gas temperature, but lower brake thermal efficiency. Then, the HC, CO, and CO2 are decreased for all higher alcohol-
biodiesel blended fuels. However, NOx, showed an increasing trend due to the increase of injection quantity and lower cetane number. It can be proved that isobutanol may be utilized as a preferential substitution with biodiesel and petroleum diesel
Functionalized iron oxide supported on graphene oxide for hyperthermia application / Umar Ahmad Abulfathi
No full textCancer is one of the major causes of death globally (9.6 million in 2018). Magnetic
hyperthermia therapy (MHT), a cancer therapy carried out at cellular level, has prospects
in reducing these death rates. It is based on the concept that; magnetic nanoparticles
(MNPs) deposited at cancer sites generate heat when exposed to an alternating current
magnetic field and consequently destroy only the cancer cells by exploiting their
vulnerability to heat. Thus, flaws like damage to healthy tissues and multidrug resistance
associated with conventional treatments are avoided. As a challenge, using MNPs in their
bare form can result in phagocytic capture, reducing their general tolerance in MHT.
Henceforth, the surface of bare MNPs is modified. Unfortunately, such modification
significantly reduces its heating efficiency, which implies a decline in MHT performance.
This study curbed these challenges by fabricating a new magnetic hybrid nanostructure
(MHNS); it mainly comprises Fe3O4 nanoparticle (FeNPs; one of the unique phases of
MNPs), polyethylene glycol (PEG; a temperature-responsive surfactant) and graphene
oxide (GO) nanoplatform. In a facile stagewise ex-situ approach, FeNPs was synthesized,
functionalized with PEG (denoted as FAP), and finally grafted onto GO to form the
MHNS. Optimizing the process by varying the composition loading reflects in the
magnetic behavior; saturation magnetization values of 68.36, 60.89 and 40.76 emu/g were
recorded for FeNPs, FAP and MHNS, respectively. All the VSM magnetization curves
overlapped completely (S-shape), implying superparamagnetic behavior. Accordingly,
these indicate successful functionalization and grafting. Interestingly, these indications
also conform with the size increase (9.24, 11.97 and 12.25 nm, respectively) observed
from XRD analysis and the detection of Fe, C, O and N elements by FESEM-EDX
instrument. The presence of FeNPs in the synthesized products was affirmed by the
consistent appearance of peculiar IR-band (around 550 – 578 cm-1 which was assigned to
Fe – O vibration) in all the FTIR spectra. As aimed herein, the heating capacity of the
iv
MHNS quantified by specific absorption rate (SAR) should be efficient. It was observed
to depend on concentration, composition, viscosity, magnetic field strength and for the
first time pH. Grafting functionalized FeNPs (FAP) onto GO nanoplatform (which
supports clustering the FAP) at 4:1 ratio improved the heating efficiency by 1.7-fold;
dispensed 2-fold heat at simulated tumor microenvironment pH (4.5 – 6.98) compared to
healthy cells microenvironment pH (> 7); timely generate significant amount of heat for
prolonged period and reached 10 oC maximum temperature rise at 1.5 mg/mL, 15 kA/m
and 316 kHz. These introduced a smart self-control attribute that could only yield the
required thermal sensitization. Lastly, the SAR-viscosity relationship shows that SAR
only drops with intense rise in heating medium viscosity (760-fold) and remains roughly
constant at lower viscosities (ƞ < 34 mPa.s), an indication that the heating mechanism is
dominated by Néel relaxation. This relationship implies that the MHNS can perform in
complex media like lymph and Cerebro Spinal Fluid (ƞ < 6 mPa.s). These results pave
the way for fabricating new MHT materials, efficient at lower concentrations and cellular
level pH
Assessment of mental health of work from home employee due to movement control order / Duan Jin
No full textThe emergence of COVID-19 has crossed the borders at a speedy rate and has infected more than 80 million people from the worldwide. The emergence of lockdown and new
norms has drawn the public's attention to the economic recession and lifestyle changes. However, the public neglected their mental health at the same time. At the early stage of the Movement Control Order (MCO), we conducted a pre-survey on the psychosocial hazards faced resulted from work from home concept during the MCO. Among the responds collected from 67 respondents, the most feedbacks obtained are 89.55% of respondents complained their working environment at home is poor and not suitable for
long hours of working while 67.16% of them complained that their psychosocial issues arise from working alone at home for long hours and lack of social events. 44.78% of
respondents complained that household chores and disruption from family members make them mentally stressed. As for mental stress, ZUNG Anxiety Self-Assessment scale
was used to assess the employees’ anxiety level and the psychosocial safety climate was introduced to assess employees’ satisfaction towards their employers. The questionnaire was given out through an online platform and 95 responds were collected. According to the data analysis by SPSS software, we found that anxious symptoms do occur through participants. The most vulnerable group was assigned to the female employee, an employee with bigger household size and higher education level among our analysis. To
improve employees' mental health, the employer can pay more effort towards these vulnerable groups in psychosocial safety climate perspective by enhancing organization
participation and involvement
Machine learning-based classification of Covid-19 using chest radiography images / Chan Yu T'ng
No full textThe novel coronavirus disease, also known as COVID- 19, was first reported in Wuhan, China and has since spread around the world. Up to July 2021, it has infected over 197 million people and caused over 4 million associated death worldwide. As the number of reported cases escalates, most countries are running out of resources. The scarcity of testing kits, lengthy testing time, and the growing number of daily cases urged researchers around the world to devise alternative methods such as medical imaging to be used in conjunction with computer aided diagnosis systems, to assist radiologists and physicians in detecting COVID- 19 cases more quickly and reliably. The aim of this project is to implement a machine learning- based binary classifier that can detect COVID- 19 positive cases from COVID- 19 negative cases using chest CT images. Transfer learning technique in conjunction with VGG16 and ResNet50 architecture has been adopted in developing the binary classifier. To achieve an optimal performance of the baseline models, many performance improvement strategies such as data augmentation, re- training of weights, fine- tuning of hyperparameters, and 5- fold cross validation have been implemented and incorporated. Thorough experimentation demonstrates that the proposed classification models are computationally less expensive while yielding astoundingly good results where Model 1 based on VGG19 architecture achieved an accuracy of 95.19% and Model 2 based on ResNet50 architecture achieved an accuracy of 98.29%
Investigation of in vivo cardiac chambers composite rendering / Muhammad Abdullah Adli Ahmad Kamal
No full textHeart disease is the most common cause of death in the world annually. Many fatalities can be avoided if the anomalies in the condition of the heart can be detected earlier for which proper treatment and preventive action can be taken. Detection of this anomalies can be done noninvasively through medical imaging modalities such as by using Computed Tomography (CT) scan. However, accurate interpretation of the heart using 2D images are often hard to do as it is visualized on a flat plane. Therefore, it is important to have a clear representation of the heart using a 3D model which would enable a more accurate interpretation of the heart and its inner chamber to be done for the detection of any anomalies. A 3D model reconstructed through the VTK program software using layers of 2D CT scan images are therefore proposed for this purpose. In this study, 399 layers of 2D CT scan image was used for the 3D model reconstruction. As a comparison, another 3D model was also reconstructed with the same 2D CT scan images using another software, 3D slicer. Although both software is able to reconstruct a good model of the heart, VTK appears to be the superior option for investigating the inner chambers of the heart. Both software also allows the measurement of the length between two points which enables the length of object under investigation to be estimated. In conclusion, VTK is able to reconstruct a good 3-dimensional representation of the heart which helps medical practitioners to better detect anomalies in their patients
Solving fractional differential equations using iterative homotopy analysis method / Lee Meng Oon
No full textSolving fractional differential equations (FDEs) using homotopy analysis method has been a challenging issue. It is mainly related to the difficulty of evaluation and low convergence rate at necessarily high order approximations. This research proposes iterative homotopy analysis method (IHAM) to fill the gap in the existing approach. At each iteration, an optimal convergence control parameter is computed that corresponds to a global minimum error of solution. When a fractional derivative of a function is much harder to evaluate, especially those involving both left-handed and right-handed fractional derivatives, it is possible to approximate the function through Taylor expansion. Numerical comparisons were conducted through various FDEs selected from the literature. The presented results conclude that IHAM delivers faster convergence and better accuracy. We hope that this study will initiate further research to identify other properties that would lead to a stable analytical method for FDEs
Analysis of interface pressure for double curves in idiopathic scoliosis patients / Noor Asliza Ahmad
No full textScoliosis is a sideway curvature of the spine more than 10 degrees. Scoliosis is grouped
into age groups where the children under the age of three, the disease is called "infantile
scoliosis" and the ‘‘juvenile scoliosis’’ happen to children at the aged 3-10 years.
“Idiopathic scoliosis" usually occurs in adolescent aged 10-15 years or who have not yet
reached puberty. Scoliotic condition will get worse as the patient starts aging. This disease
can be controlled if it can be detected early. However, if left untreated, the condition of
the spine will get worse and will cause various health problems in the future including
death. To date, the main cause of the disease is still unknown. However, there are several
treatments available to control the progression.
The treatment of this disease is determined based on the degree of curvature of a
patient. For curve angle between 10 to 25 degrees, the way of treatment is observation
and appropriate exercises, while 20-45 degrees curve patients will be asked to use custommade
body braces. These special body braces are usually made up of plastic and need to
be worn for more than 20 hours a day.Body brace has been proven to be effective in
stopping the curve progression and delay the surgery. Chêneau brace is one of body brace
types. Chêneau brace has proven its effectiveness in treating patients with idiopathic
scoliosis for years. However, no studies have been reported on the analysis of interface
pressure in patients with double curve idiopathic scoliosis.
This thesis focuses on measuring the interface pressure exerted by the Chêneau brace.
A total of 72 (60 girls and 12 boys) patients aged 10 years and older participated in this
study. Two sensors were placed on the inside of the brace wall so that it is in contact with
patient’s body. The F-Socket Transducer (9811E) reading was used to assess the pressure
on the right thoracolumbar and left thoracic curves between normal and maximum tension
iv
and the pressure variation of this interface with some basic daily activities. Each patient
was asked to perform nine basic daily activities, and the interface pressure for each
activity were recorded for normal and maximum tension.
The results showed that the mean peak pressure produced in adolescent idiopathic
scoliosis curve was higher for right thoracic curve than left thoracolumbar curve in all
tasks. Pressure increased significantly at the maximum inspiration task (p <0.0001) for
both indentation types for normal and maximum stresses. Patient were followed-up for
six months and patients were asked to wear the brace in maximum tension at all times of
possible. The levels of correction for thoracic and thoracolumbar indentations were
23.2% and 34.5%, respectively, after 6 months of brace use (23 hours per day). However,
we could not find a large correlation between the mean peak pressure in the standing
position and the degree of scoliosis correction for the two curves having values of r =
0.158, p = 0.356 and r = –0.024, p = 0.889
Anxiety, depression and insomnia during Covid-19 pandemic among the public in Malaysia: The association with knowledge, attitude and practice (KAP), and social media addiction / Lim Kuok Quan
No full textBackground: The COVID-19 pandemic caused severe distress to the government and the
public. The community had to adapt to the movement control order, impacting social
interaction, employment, and schooling. The public’s knowledge, attitude, and practice
(KAP) of the pandemic and possibly frequent social media usage during sudden and
prolonged social isolation might affect one’s mental health.
Objectives: The study measured anxiety, depression and insomnia in the participants and
its association with knowledge, attitude, practice (KAP) and social media usage during the
pandemic.
Methods: This cross-sectional online survey study was conducted between April 2020
and June 2020. The participants were from the public who could understand and read
adequate Malay or English, and ≥ 18 years old.
A total of 353 participants responded and were recruited in the online survey. The
participants were assessed using the Knowledge, Attitudes, and Practices towards COVID�19 Pandemic (KAP), the Social Media Addiction during COVID-19 pandemic (SMACOP),
Insomnia Severity Index, Generalized Anxiety Disorder Scale – 7 (GAD-7), and Patient
Health Questionnaire – 9 (PHQ-9). In the KAP, scores of 13 and below were considered low,
v
while scores more than 13 were adequate. The cut-off point for depression is ≥ 5, and for
anxiety is ≥ 6. The multivariate logistic regression analysis was used for the purpose to
explore the influential factors.
Results: The average age of the participants was 42 years old, and more than half were
female (63.5%). Two-thirds of the participants were Chinese, followed by Indian (22.1%),
and only about 12% were Malay; 77% of the individuals were still working. Most of the
participants were married, and more than 70% had tertiary educational levels and above.
More than half the participants (77.3%) were equipped with adequate KAP towards this
pandemic and about half of them (45.6%) were classified as social media addicts. There were
a considerably high proportion of them had insomnia (34.0) while in 32.0% of the
participants experienced symptomatic depression. Anxiety-wise, a total of 89 individuals
(25.2%) had symptomatic anxiety.
The total KAP was significantly correlated with total insomnia (rho = -0.211; p <0.01),
anxiety (rho = -0.187; p <0.01), and depression (rho = -0.169; p <0.01) symptoms. The total
social media addiction was fair to moderately correlated with having insomnia (rho = 0.315;
p <0.01), anxiety (rho = 0.318; p <0.01), and depression (rho = 0.244; p <0.01). Multivariate
analysis revealed that insomnia was significantly related to KAP and SMACOP (95% CI: -
0.0098, -0.007; p = 0.025) and (95% CI: 0.044, 0.087) respectively. For anxiety symptoms,
there was significant association with KAP (95% CI: -0.119 to -0.019), SMACOP (95% CI:
0.057, 0.104), age (95% CI: -0.021, -0.008), and being female (95% CI: 0.063, 0.408). For
depression symptoms, there was significant association with SMACOP (adjusted B = 0.048,
95% CI: 0.025, 0.070), and age (adjusted B = -0.018, 95% CI: -0.025, -0.011).
vi
Conclusions: There is significant prevalence of anxiety, depression and insomnia among
the public during the COVID-19 pandemic. Knowledge, attitudes, and practices (KAP)
regarding the COVID-19 pandemic are crucial in determining the risk of developing mental
health issues. The higher the levels of knowledge, attitudes, and practices towards COVID�19, the lower the levels of anxiety and insomnia among the public during the COVID-19
pandemic. Misinformation and disinformation adversely affect psychological wellbeing. The
higher the levels of social media addiction, the higher the levels of anxiety, depression and
insomnia among the public during the COVID-19 pandemic. Thus, all relevant authorities
play a pivotal role in disseminating and monitoring facts and misinformation to the general
public