Non antimicrobial touch surface materials such as stainless steel can act as a medium for transmitting
microbes, leading to the increase of hospital-acquired infections and antibiotic-resistant microbes.
Copper can be used to replace the current non-antimicrobial touch surfaces, however, the high cost of
solid copper hampers copper from being the ideal choice. Therefore, stainless steel touch surfaces coated
with copper can become the option for a low cost yet effective alternative. In this study, electrodeposition
technique was used to coat copper on 304 stainless steel surface using 0.01 M CuSO4 solution, at pH 1.
The electrodeposition process was done using chronoamperometry by applying –0.25 V vs. Ag/AgCl for
15 min. Morphological observation revealed that 304 stainless steel surface was uniformly coated with
compact and dense copper. EDAX analysis showed the composition of copper of 98.9 wt. %, ranging
in diameter from 60-90 nm grain size. Thickness of the coating was approximately 105.8 nm. The
antibacterial property of copper coating was analysed by both Gram negative E. coli and Gram positive
S. aureus. Results indicated that copper coating has excellent antibacterial behaviour in destroying both
bacteria. E. coli was more sensitive to the biocidal action of the copper coating of which 100 % reduction
was observed within 5 min of exposure. As for S. aureus, a 100% reduction was achieved only after 10
min of exposure.
This animal modelling study aimed to investigate the effects of LDR exposure on cellular ROS production,
oxidative DNA damage, and alteration of cellular ultrastructure and apoptosis-related protein expressions.
Ten male ICR mice were randomly divided into two groups consisting of control (Cx) and radiation
(Rx) groups. On day 29 of post-acclimatisation, mice underwent total body irradiation with 100 µGy
X-ray. Liver and lung tissues were assessed for the levels of cellular ROS production and Apurinic/
Apyrimidinic sites generation. Ultrastructural alteration was detected using TEM, alteration of p53,
Bax, and Bcl-2 expressions was determined by western blotting. Results showed that exposure to LDR
significantly increased the levels of cellular ROS and AP sites in mice. Ultrastructure of the nucleus in
Rx showed nuclear blebbing and structural changes in morphology that indicate cell death. Meanwhile,
p53, Bax, and Bcl-2 proteins increased in expressions and altered the balance of Bax/Bcl-2 ratio. These
findings may postulate that LDR exposure may enhance oxidative DNA damage and alter expression
of apoptosis-related proteins.
This paper is a Computational Fluid Dynamics (CFD) study of the performance of a jet engine annular
combustor that was subjected to various loading conditions. The aim is to comprehend the effect of
various genuine working conditions on ignition and emission performance. The numerical models utilized for fuel ignition is the feasible k-ω model for turbulent stream, species transport (aviation fuel and air) with eddy-dissipation reaction modelling and pollution model for nitrogen oxides (NOX) emission. The results obtained confirm the findings described in the literature.
Kenaf natural fibre is used as a sustainable form of material to reinforce polymeric composite. However, natural fibres usually do not perform as well as synthetic fibres. Silica nanoparticle is a material with high surface area and its high interfacial interaction with the matrix results in its improvement. In this research, silica nanoparticles were introduced into epoxy resin as a filler material to improve the mechanical properties of the kenaf-reinforced epoxy. They were dispersed into the epoxy using a homogeniser at 3000 rpm for 10 minutes. The composites were fabricated by spreading the silica filled epoxy evenly onto the kenaf mat before hot pressing the resin wet kenaf mat. The results show for flexural properties, composites with higher fibre and silica volume content generally had better properties with specimen 601 (60 vol% kenaf and1 vol% silica) having the highest strength at 68.9 MPa. Compressive properties were erratic with specimen 201 (20 vol% kenaf and 1 vol% silica) having the highest strength at 53.6 MPa.
This paper presents a tracking method based on parameters between colour blobs. The colour blobs
are obtained from segmenting the overall target into multiple colour regions. The colour regions are
segmented using EM method that determines the normal colour distributions from the overall colour
pixel distribution. After segmenting into different regions on the different colour layers, parameters
can be generated between colour regions of interest. In this instance, the colour regions of interest are
the top and bottom colour regions. The parameters that are generated from these colour regions are
the vector magnitude, vector angle and the value difference between colour regions. These parameters
are used as a means for tracking targets of interest. These parameters are used for tracking the target
of interest across an array of cameras which in this instance are three cameras. Three cameras have
been set up with different background and foreground conditions. The summarised results of tracking
targets across three cameras have shown that the consistency of colour regions across different cameras
and different background settings provided sufficient parameters for targets to be tracked consistently.
Example of tracking performance across three cameras were 0.88, 0.67 and 0.55. The remaining tracking
performances across three cameras are shown in Table 2. The tracking performance indicate that the
parameters between colour regions were able to be used for tracking a target across different cameras
with different background scenarios. Based on results obtained, parameters between segmented colour
regions have indicated robustness in tracking target of interest across three cameras.
An electric power system generate electricity to meet demands. Distributed Generation (DG) allows
electricity to be generated in a small capacity where the customer is located. In this paper, multi-objective
functions based on the indices of system performance are formulated and used to determine the best
location. The Differential Evolution technique (DE) has been employed to calculate optimal sizing for
each location. Unity power factor DG model have been studied in this work and the problems solved
with one DG unit. IEEE 14 bus has been used as a test system.
In this paper, a configuration of a single-stage AC-DC converter and a high voltage resonant controller
IC L6598 for LED street light driver is discussed. The converter is obtained by integrating two boost
circuits and a half-bridge LLC resonant circuit. A voltage double rectifier circuit is adopted as output
to lower the voltage stress on transformer and the associated core. The two boost circuits work in
boundary conduction mode (BCM) to achieve the power factor correction (PFC). The converter works
in soft-switching mode allowing the power switches to operate in zero-voltage-switching (ZVS) and
the output diodes to operate in zero-current-switching (ZCS). This reduces the switching losses and
enhances the efficiency. The converter features lower voltage stress on the power switches and the bus
voltage is reduced to slightly higher than the peak input voltage. Therefore, the converter can perform
well under high-input-voltage. Here, the DC bus and the output filter capacitances are greatly reduced.
So, electrolytic capacitor-less converter can be realized for a long lifetime LED driver. Simulation results
from PSpice are presented for a 100-W prototype.
Hydrogen fuel cell (HFC) is one of the renewable resources to address fossil fuel depletion and global
warming. Its primary advantages are power is generated from renewable fuel hydrogen and the emission
is only water. However, HFC supplies power in a slow dynamic response. In fuel cell electrical vehicle
(FCEV), energy storage system (ESS), i.e. supercapacitor and battery, is required to immediately
compensate the difference between load demand and power supply; the lifetime of HFC is affected
by current ripple. In order to manage power flow between HFC and load, HFC is interfaced with a
unidirectional DC-DC converter. The converter steps up the terminal fuel cell voltage and regulate the
voltage before it is connected to the load. Among the proposed HFC DC-DC converters, interleaved
DC-DC converter seems more suitable for FCEV application due to its advantages. When galvanic
isolation is required, current fed full bridge converter receives significant consideration as the module
of interleaved converter. This paper simulates interleaved current fed full bridge (ICFFB) converter and
discusses the suitability of ICFFB for FCEV application.
This paper proposes a novel double series resonant dc-dc converter with uniform voltage stress on a
transformer. It consists of a half-bridge inverter with two power switches (IGBTs), two series resonant
tank, two high-voltage transformers and a symmetrical voltage multiplier circuit. A symmetrical voltage
multiplier circuit is connected at the secondary side of the high voltage transformer to generate desired
high voltage dc output. Due to use of voltage multiplier circuit, the proposed converter requires smaller
turns ratio of the high voltage transformer, leading to reduction in size and volume of the transformer.
The proposed converter operates in discontinuous current mode by varying the switching frequency of
the converter. In a discontinuous current mode operation, all the power switches and output diodes of the
rectifier circuit turn-on and turn-off under zero current switching conditions. Therefore, it has features
of low switching losses and possibility of light-load operation. Besides, it costs less and is smaller in
size compared with conventional double series resonant dc-dc converter. It also has a simple operating
principle and suitable for high voltage and high power applications. Experimental results confirm the
proposed converter performs better than the others.
Graphene band structure can be modulated when dopant atoms are introduced into graphene sheets. As
a result, there is flexibility in design and optimisation of electronic devices. In this study, the effects
of atomic doping to graphene band structure were investigated by using boron and oxygen as dopant
atoms. Different dopant concentrations and dopant locations in graphene sub lattices were studied by
using a 4x4 graphene sub lattice which consists of 32 carbon atoms. Results show that both dopants
cause opening of energy band gap of mono layer graphene. The highest energy band gap (Eg) value for
graphene doped with boron is 0.52 eV and the highest Eg value for graphene doped with oxygen is 1.67
eV, in which both results are obtained for highest dopant concentration and farthest dopant’s distance in a
graphene sheet. This shows that higher dopant concentration and farther dopant’s location in a graphene
sheet lead to higher energy band gap.
Researchers have observed the impact of climate changes on overhead line outages. It is known that
overhead lines are very prone to lightning strikes due to their height and location which are normally in
an open and exposed area. Studies have also reported that transmission and distribution lines experience
very high failure rates due to lightning strikes. The tropics experience greater lightning activities and
have higher peaks where transmission lines suffer frequent line outages. This paper examined studies
that have been conducted on line outages due to lightning activities, especially in the tropical areas.
Lightning detection system is also discussed as well as how to evaluate line performance. Seasonal
variation of lightning occurrences and line outage pattern help to predict lightning occurrences and to
optimise a suitable power protection system of overhead lines. It has been widely reported that lightning
occurrences and line outages are significantly related and lightning activity was more prevalent during
inter monsoon seasons.
The radiation absorption distribution of electromagnetic energy into the breast phantom is of fundamental
importance in understanding its therapeutic capability emitted by the microstrip applicator for noninvasive
hyperthermia procedure. In this paper simple microstrip applicator with rectangular shape is
presented. Different operating frequency were investigated to observe radiation absorption distribution,
which is measured through specific absorption rate (SAR) parameter. The operational frequency was
915MHz and 2450MHz, the industry, scientific and medical (ISM) frequency range. As simulated by
using the finite difference time-domain (FDTD) computational simulation which is known as SEMCAD
X solver, the results shed an interesting observation on the SAR when frequency varies, which is shown
by the transformation onto the penetration depth and focusing capability onto the breast area to be treated.
Flexible AC Transmission System (FACTS) devices are used in to improve stability and loadability of
transmission networks as well as minimise losses . Types of FACTS that are normally used are Thyristor
Controller Series Compensator (TCSC) and Unified Power Flow Controller (UPFC) which is to control
power flow and stability of the power system at a certain location. The TCSC is suitable because it can
be installed in a long transmission line system while UPFC can solve any reactive power problems.
The objective of this study is to minimise total power losses and to improve the voltage profile by using
FACTS devices in the transmission system. This paper proposes a static voltage stability index (SVSI)
to determine the size and placement of TCSC and the Evolutionary Programming (EP) technique. The
results of the transmission line losses and voltage profile using TCSC and UPFC are compared in order
to demonstrate which FACTS device can produce better results. The IEEE 14 bus system is used in this
study to validate the findings.
Power systems are usually exposed to numerous disturbances that can have an adverse effect on system
operation. Insufficient generation could lead to frequency declination and subsequently system collapse
in the absence of immediate control action. Frequency Load Shedding (UFLS) is a technique commonly
applied to overcome overloading and restore the system frequency. This paper presents an adaptive load
shedding approach to determine the best location with minimum amount of load to be shed. Load Ranking
Fuzzy Logic (LRFL) is used to rank the load based on their sensitivity and stability index. In order to
achieve this, the proposed strategy is verified using 11 kV Malaysian distributed network consisting of
different type of loads connected with single and multiple Distribution Generator (DG). The simulation
results show that the proposed strategy successfully stabilizes the system’s frequency.
This research presents compensation of current harmonic disturbance in power system network using
shunt active power filter. In this paper, harmonic extraction using Synchronous Reference Frame
Fundamental technique (SRFF) was investigated for three phase 3-wire system. It proposes a method
based on direct current measurement of load currents using a band pass filter at low cut off frequencies
to improve the filtering ability in highly contaminated loads. The proposed filter consists of second
order low pass and high pass filters cascaded together at suitable frequencies, estimated based on the
output of these units to mitigate the current harmonics. The performance of the system was simulated
in Matlab Platform and evaluated considering total harmonic distortion of the source current in a threephase
balanced network. The simulation results show the ability of the proposed tracking scheme to
accurately estimate harmonics.
Negative bias temperature instability (NBTI) is a common phenomenon in a p-channel MOSFET device
under a negative gate-to-source voltage at a high stress temperature. This paper presents the NBTI
characterisation based on different analysis methods and stress conditions on p-MOSFET devices. The
atomic hydrogen concentration is probed at interface, Poly-Si and channel of p-MOSFET under study
using SILVACO TCAD tool. In addition, the behaviour of the permanent and recoverable component
was investigated based on AC stress at different stress conditions using Modelling Interface Generation
(MIG) tool. The results show that increases in temperature, negative voltage stress gate and decreases
in frequency increase the threshold voltage shift, thus enhancing NBTI degradation.
This paper presents a methodology to determine the economic power factor at the point of power transfer
between transmission and distribution (T & D) system for a vertically integrated utility company. An
integrated reactive power management strategy is developed to optimize the planting up of reactive power
compensation devices in the transmission and distribution system. The transmission and distribution
network is modelled and simulated using commercially available software to analyse the transmission
network losses, capacity released and voltage stability due to capacitor plant up. Economic analysis on
the total cost of ownership of capacitor banks is used to determine the economic benefits of technical
losses reduction and capacity. released in transmission and distribution equipment through the planting
up of capacitor bank. The proposed methodology can be used by a vertically integrated power utility
where a single utility own both the transmission and distribution system. A software base data analytic,
power system automation and economic analysis tool was developed to facilitate the planning engineer
in reactive power planning and management.
Planar electromagnetic sensors are widely used in many applications due to its low cost, simple
architecture, and fast response. Currently, there are many types of membranes which have been introduced
to remove contaminants from an aqueous solution. Hence, the water quality could be maintained and
safe to consume. The objective of this paper is to apply and investigate the effectiveness of a selective
membrane in detecting nitrate, phosphate, zinc, and nickel ions by means of planar electromagnetic
sensors array (PESA). The samples have four different concentration levels, 5 ppm, 25 ppm, 75 ppm,
and 100 ppm. The selective membrane’s performance is evaluated based on absolute average sensitivity
(|Z%|). This performance is compared with conventional coating such as incralac. The developed
membrane consists of two elements which are polymer and solvent. Modified silica is selected as a
polymer material while N-(2-Aminoethyl)-3 Aminipropyltrimethoxysilane is selected as a solvent. The
selection of these materials is based on their ability to attract the contaminants in the aqueous solution
and hence increased the selectivity. The proposed sensor with a membrane shows its higher sensitivity
compared to incralac. The highest sensitivity is 338 % which observed in the presence of membrane
for the nickel detection. Meanwhile, the lowest sensitivity using membrane is 12 % for zinc detection.
Radio telescope is an application that requires a precise position control as it should point to the exact
coordinate so that it could receive the desired signal. The main idea of this paper is to optimise the PID
controller by introducing slope variation method in order to control the position of a radio telescope.
This proposed method is also validated with the presence of disturbance, such as wind gust disturbance
with different speed amplitude. The results indicate that the proposed optimisation method has a better
result with no overshoot and able to attenuate wind gust disturbance when compared with conventional
PID controller.
In this study, nitrogen doped titanium dioxide-based dye-sensitised solar cell was successfully fabricated
using screen printing technique to discover the optimisation of process parameters for the solar cell
efficiency using response surface methodology (RSM). Parameter optimisation has been a major concern
in solar cell fabrication. The selected parameters were: nitrogen concentration (15-25 mg of urea), the
film thickness (25-60 µm) and dye loading time (12-24 hours), the optimum condition which yields the
highest efficiency of 3.5% was at 15 mg nitrogen concentration, 25 µm film thickness and 24-hours dye
loading time. Film thickness was found to have a significant influence on efficiency while the loading
time exceeding 18 hours has the least significant effect.