UniMAP Library Digital Repository
Not a member yet
77924 research outputs found
Sort by
Microwave drying characteristics of Mas Cotek (Ficus deltoidea) leaves and its effects on colour and antioxidant properties
No full textMaster of Science in Bioprocess EngineerngFicus deltoidea or locally known as Mas Cotek in Malaysia is one of the 10 prioritized herbs shortlisted by the government of Malaysia in its Economic Transformation Programme (ETP). The herb is rich in chemical constituents which are known to have
diverse therapeutic potentials such as reducing level of sugar in blood, decreasing blood
pressure, contracting the vagina after delivery, delaying menopause and reducing the
risk of cancer. Ficus deltoidea is commonly consumed, stored and further processed in
its dried form. High quality dried Ficus deltoidea leaves are therefore sought after by
the end-users and drying is therefore the most effective method to remove moisture to
preserve and extent the shelf-life of the herb. In this study, the thin layer microwave
drying characteristics of Ficus deltoidea leaves were investigated and the corresponding
quality of the dehydrated leaves such as the colour, total phenolic content and
antioxidant properties, were evaluated with respect to the fresh leaves. Three microwave
power levels (300, 600 and 800 W) and three ventilation rates (0.00, 0.013 and 0.025
m3/s) were the combination of drying parameters used to examine the drying
characteristics and quality changes of dried Ficus deltoidea. A modified domestic
microwave heater was used in the study. Microwave power levels were found to
significantly (p < 0.05) affect the drying rate and the quality of the dehydrated Ficus
deltoidea leaves. The drying rate increased as the microwave power level increased. The
colour quality, total phenolic content and antioxidant properties were higher at the
microwave power level of 600 and 800 W as compared to 300 W (p < 0.05) irrespective
of ventilation rate. On the other hand, the effects of the ventilation rates on the drying
rate and quality of dehydrated Ficus deltoidea leaves were found to be insignificant (p >
0.05) at all drying treatments. The thin layer drying characteristics of Ficus deltoidea
leaves were evaluated and it was found that the drying took place in the falling rate
period only. Five established thin layer drying models were used to compare the
experimental and predicted drying kinetics by using statistical software analysis. Based
on the fitting criteria, Midili et al. model appeared to best fit the thin layer microwave
drying data. Finally, the assessment of sorption isotherm is crucial in order to ensure
stability of the dehydrated Ficus deltoidea leaves during storage. Static gravimetric
method was used to determine the moisture sorption isotherm (adsorption and
desorption) of Ficus deltoidea leaves at two temperatures (5 and 30 °C) and five relative
humidities ranged from 11.26 to 75.65 %. Five established isotherm models were used
to compare the experimental and predicted sorption isotherms by using statistical
software analysis. Based on the fitting criteria, Peleg model appeared to best fit the
sorption isotherms data. The characteristic of the shape of the sorption curves were
found to fall under the Type II category. As a conclusion, drying treatment of 600 W
and 0.013 m3/s is suggested as drying conditions of Ficus deltoidea leaves for optimum
dried leaves quality retention
Feature enhancement and selection methods for isolated Malay speech recognition
No full textDoctor of Philosophy in Biomedical Electronic EngineeringAutomatic speech recognition (ASR) is a technique to translate automatically incoming speech signal into their contextual information. In the pass few decade, various acoustic feature extraction and classification algorithms have been developed for native English speech recognition and different languages spoken around the world using acoustic signals. Research in Automatic Speech Recognition (ASR) by machines had been done for more than five decades. Various research findings have been reported in recent years in speech recognition for many different languages. However, every languages having
their own unique words structure. As examples, English words are formed due to the changes of phoneme in the based word itself according to its group of words and Malay words allow addition of affixes to the base word to form new words. In this research,
signal processing techniques are applied to the acoustic signals in an effort to recognize
the Malay speech. To reduce the misclassification, the recorded speech signals were
segmented to remove the unvoiced speech (noise). In this research works, parametric
Linear Prediction Coefficients (LPC), Linear Prediction Cepstral Coefficient (LPCC),
Weighted Linear Prediction Coefficients (WLPCC), Mel-Frequency Cepstral
Coefficients (MFCC) and non-parametric Wavelet Packet Transform based Energy and
Entropy (WPT-EE) representations of features were extracted. The features extracted
were enhanced to increase the discriminant ability using artificial bee colony based
clustering. Then, the enhanced features set were dimensionally reduced by using two
feature selection techniques. They are binary particle swarm optimization (BPSO) and
discrete artificial bee colony (DABC) feature selection technique. Last, two classifiers
as the probabilistic neural network (PNN) and extreme learning machine (ELM) were
used to evaluate the performance of extracted and enhanced features from recorded
Malay speech signal. The proposed artificial bee colony based feature enhancement
(ABC-FE) features show promising average results of 99.61% (Speaker Dependent) and
96.21% (Speaker Independent). Experimental results showed that the average accuracy
obtained by using hybrid features of LPC, LPCC, WLPCC, MFCC and WPT-EE for
Speaker Dependent and Speaker Independent with ELM classifier were 97.89% (PSO)-
98 features and 99.33% (ABC)-67 features for Malay speech recognition
Characterization and mechanical properties of geopolymer materials using kaolin and white clay for coating application
No full textMaster of Science in Materials EngineeringGeopolymer exhibit a wide variety of properties in various applications including coating. Geopolymer as inorganic coating has good bonding structure of amorphous inorganic polymer which has excellent bonding agent properties and form at low temperature compare to organic coating. The use of new source materials such as kaolin and white clay has potential as geopolymer coating plus can reduce the use of existing cement as main material in existing cementitious coating. The performance of kaolin and white clay geopolymer coating has been tested on glass reinforced epoxy (GRE) pipe sample which provided from Saudi Arabia. The parameter to find the best mix design for kaolin and white clay is by fixing the solid/liquid ratio at 1.0 while the ratio of Na2SiO3/NaOH ratio is verified and has been cured at room temperature, 80°C, 200°C and 400°C to get the stable coating surface based on coating properties appearance before proceed to the strength testing. The microstructure of
kaolin and white clay geopolymer coating were testing under chemical composition analysis, phase analysis and morphology analysis for raw materials (kaolin and white clay) and geopolymer coating products (kaolin and white clay). After sample of Na2SiO3/NaOH ratio from 0.40 – 0.60 can stand cured at room temperature, 80°C, 200°C and 400°C, sample then is proceed to mechanical strength testing by flexural strength, adhesive strength, water absorption, and hardness to get the best formulation. The morphology of the interfacial layer contact between substrate (glass reinforced epoxy sample) and geopolymer coating (kaolin and white clay) layer is studied using optical microscope. The best mix design for kaolin geopolymer coating was at 0.45 ratio Na2SiO3/NaOH with maximum flexural strength at 33.88 MPa. The adhesive strength at this mix design was among the highest strength which is 5.5 MPa as well as the water absorption achieved the lowest percentage at this mix design which is 1.91 %. During hardness test, the highest strength (229.8 MPa) was identified in the best mix design kaolin geopolymer coating
Study on sensing properties of chitosan-polyethylene oxide-exfoliated graphite based toluene sensors
No full textMaster of Science in Polymer EngineeringChitosan was used as a material to fabricate film sensor because of its structure and properties where it consists of amino group which has free electron. In this study, chitosan was added with polyethylene oxide and exfoliated graphite to study the
electrical properties toward wet air, dry air and toluene. Chitosan powder was dissolved in 2.00 v/v% of acetic acid to form chitosan solution. Then, the chitosan solution was added with polyethylene oxide and exfoliated graphite based on the ratio needed. The composition of the materials was varied and fabricated on gold plated printed circuit board by using electrical deposition technique. Chitosan/polyethylene oxide/exfoliated graphite matrix films were prepared to observe the effect of exfoliated graphite concentration on microstructure, electrical conductivity, and sensing properties of the films. The chitosan/polyethylene oxide/exfoliated graphite film was prepared with various concentration of exfoliated graphite to obtain the best concentration of exfoliated graphite to achieve the excellent properties of the films. The SEM technique was employed to analyse the micro- structure of the prepared chitosan/ polyethylene oxide / exfoliated graphite. The FT-IR was used to analyse the functional groups existence in the chitosan/polyethylene oxide/exfoliated graphite films. From the result obtained, this project successfully proved that the addition 0.4w/v % of exfoliated graphite onto chitosan/polyethylene oxide film has improved the sensing properties of the films. The chitosan/polyethylene oxide/exfoliated graphite films have better response, sensitivity and stability compare to chitosan/polyethylene oxide films
Citric acid leaching process for silica extracted from oil palm ash for zeolite synthesis
No full textDoctor of Philosophy in Materials EngineeringAgricultural wastes such as oil palm ash have a possibility to be utilized as a useful renewable source for production of energy and silica (SiO2). Extensive researches have been carried out to extract silica from agricultural wastes, due to silica as a useful raw material for industrial application. Oil palm ash is one of the waste material from the palm oil industry where is was obtained from the burning process of solid waste such as empty fruit bunch, shell and fiber. Oil palm ash contains a large amount of silica. This study has been conducted to extract silica from palm ash by removing impurities using citric acid via leaching process. Various experimental parameters, such as acid concentration (1 to 6 %), reaction time (30 to 180 minutes), leaching temperature (30 to 90 C) and solid/liquid ratio (1:50 – 1:10) were investigated. Then, the effect of each parameter towards extraction process was evaluated using XRF, FTIR, XRD and SEM. The optimum extracting condition was achieved at 3% concentration of citric acid, 70C of solution temperature, 60 minutes of reaction time and 1:25 ratio of solid/liquid. XRF results show that the content of silica in treated palm ash can reach up to 92% after citric acid leaching treatment. The transmittance peaks at 798 - 778 cm-1 show that silica element is absent in the treated palm ash. Preliminary tests have shown that there is a possibility of using silica extracted from palm ash to synthesize zeolite
Hybrid filters for edge detection and its new fuzzy performance evaluation technique
No full textMaster of Science in Engineering MathematicsEdge detection is an important operation in digital image processing and also very important in field of computer vision, image segmentation and object recognition. Edge is line between two corners or surface which also a significant colour transition in an
image. It also can be defined as an abrupt change in intensity of pixels and discontinuity in image brightness. The primary goal of edge detection methods is to extract the important feature or information in an image. In this study seven different techniques are
used to extract the edge points for two different images. The seven techniques are
involved the classical edge detectors as well the hybrid of the filters such as Sobel,
Prewitt, Freichen, Robert, Sobel-Prewitt, Sobel-Freichen and Robert-Freichen.
Performance factors are analysed in term of qualitative and quantitative aspect.
Frequency distribution is used to measure the number active pixels in edge detected
images. Frequency distribution is a measurement of quantitative based on the edge maps
to each other relatively through statistical evaluation. The evaluation process is all added
with qualitative aspect by visual analysis in term of good localization using fuzzy logic.
A set of rules based on intensity of edges such as rate of ‘missing edges’,’thick edges’
and ‘broken edges’ defined. The conventional method required the human interpretation
to decide upon the detection. Finally, performance evaluation is compared using Edge
detection index. The indices used in Edge Detection Index are the sum of frequency
distribution and visual perception scale of an image which will be obtained from fuzzy
logic. The higher value of edge detection index indicates the better the filter. Overall
findings indicated hybrid of Robert Freichen outperformed other combination of gradient
filters with value of 2.73 in edge detection index for image 1(Lena) and 2.65 for image
2(Mechanical parts)
Enhancing the thermal performance of courtyard office building in hot-humid climate : a case study of development department building UniMAP
No full textMaster of Science in Building EngineeringCourtyard is considered a natural alternative for cooling since it has high ability to create
a local climate within a building that is nicer than the outside which leads to create
temperature difference between indoor and outdoor. The efficiency of courtyard in hothumid
climate still questionable due there are minimal research reported especially in
Malaysia. The objective of this research is to perform a simulation study using
EnergyPlus simulator to explore the influence of the presence of a courtyard in a single
storey office building via investigating the impact of natural ventilation, window glazing
and window blind shading on the thermal performance of the building on 21 April and 21
October that representing the dry season and wet season days in Malaysia. The
Development Department building at University Malaysia Perlis (UniMAP) that is
located in Pauh Putra Campus has been taken as a case study. The results show that the
stack ventilation is the most effective way to reduce the indoor air temperature due to its
high ability on exchanging the indoor warm air with the cooler one in the courtyard. In
contrary, the cross ventilation has the greatest impact on reducing the relative humidity
within the building since it is capable to dilute the moist concentration in the interior
spaces as a result of airflow. The best PMV values for ventilation effect is obtained for
stack ventilation, indicating its effectiveness in enhancing the thermal comfort of the
building. Moreover, venetian blind shading is capable to reduce the indoor air temperature
for the building and using external blind is more effective due to its impact on blocking
sun radiation. Additionally, the external venetian blind causes to increase the relative
humidity within the building compared to no window shading case due to the reduction
of air temperature. Generally, window shading reveals an enhancement on PMV values
and the external blind has the most effective where it is capable to shift PMV values
within comfortable level during wet season, but it does not much impact on the thermal
sensation level during dry season. Using double and triple glazing windows able to
reduces the indoor air temperature and in contrary, relatively increases the humidity
within the building compared to using single glazing window. The PMV values of glazing
effect revealed that using multi-layered glazing window slightly enhances the thermal
sensation for occupants but it is not able to reduce the uncomfortable hours on both design
days. Finally, it can be observed that the ventilation is the most effective factor on
reducing the air temperature and relative humidity, as well as to enhance the thermal
comfort level for courtyard buildings in hot-humid climate among the other studied
parameters. This work contributes to sustainable architecture where courtyard application
concept is used in hot-humid climate specifically for Malaysia due to its effective ability
to enhance the thermal performance and help in improving the thermal comfort level near
to the desired values
Computational design and development of molecular imprint polymer for selective extraction of andrographolide from andrographis paniculata
No full textMaster of Science in Bioprocess EngineeringThis research study highlighted on computational design and molecular imprint polymer
development for the extraction of andrographolide from Andrographis paniculata (A.
Paniculata). Molecularly Imprinted Polymer (MIP) is one of the “Lock and Key”
approach, where MIP is the lock and andrographolide is the key which fits the MIP lock
both physically and chemically. Hyperchem 8.0.10 software was used to simulate and
determine the suitable functional monomer and optimum template-functional monomer
ratio for the best complexity among them. The MIPs were prepared by non-covalent
precipitation polymerization. Andrographolide, methacrylic acid, and ethylene glycol
dimethacrylate were used as template, functional monomer, and cross-linker,
respectively. Non-imprinted polymer (NIP) was developed in the same manner as a
control. The template molecules were removed from MIP polymer particles using
methanol: acetic acid (1:1 v/v) solvent. MIP and NIP were characterized by Fouriertransform
Infrared Spectroscopy, Scanning Electron Microscope and dynamic asorption
study. The efficiency of andrographolide imprinted MIP were evaluated in separation and
sensor applications. For the separation analysis, rebinding assay and adsorption isotherm
studies were conducted. The imprinting factor of MIP is 2.26 with cavities distribution
of 55.45 ml.g-1. The binding assay was analyzed by three types of non-linear adsorption
isotherm. The developed MIP follows Langmuir-Freundlich isotherm with maximum
binding capacity of 149.59 μg.g-1 where the experimental binding capacity was calculated
as 167.86 μg.g-1. MIP-SPME was used to extract andrographolide from A. paniculata
with 92.3 % of recovery. The LOD and LOQ of MIP-SPME is 0.14 and 0.466 μg.ml-1,
respectively. MIP was applied in sensor development using Quartz Crystal Microbalance
(QCM) 200 where MIP was electrodeposited using cyclic voltammetry. QCM 200 device
gives the frequency changes corresponding to the selective adsorption of andrographolide
from A. panciulata. The maximum binding sites on the MIP-QCM sensor by applying
linear Langmuir isotherm is 18.02 ng.cm-2. In addition, MIP-QCM sensor could be used
in real sample analysis. It was found that 45.53 % of andrographolide detected in 0.10
μg.ml-1 of plant extract with LOD and LOQ of 1.206 ng.cm-2 and 4.020 ng.cm-2
respectively. This is the first research using MIP based QCM sensor for the quantification
of andrographolide from A. paniculata. This project demonstrated that the
andrographolide imprinted polymer can be applied both in analytical separation and
sensor development for the detection and quantification of andrographolide from A.
paniculata plant extract. Therefore, a novel molecular imprint polymer was synthesized
by precipitation polymerization which could be applied in separation and sensor studie
Development od SiC reinforced SnCu and SAC based lead-free solder composite via powder metallurgy route
No full textMaster of Science in Materials EngineeringNowadays, composite solder has gain researcher’s attention due to its promising improvement in physical and mechanical properties for lead free solder. This study was carried out to investigate the effect of SiC particle on microstructure evolution, physical and mechanical properties of SAC and SnCu based solder alloys. Both SAC and SnCu
composite solders were synthesized by powder metallurgy method (PM), which consistsof several processes such as mechanical blending, compaction and sintering. Five different weight percentages of SiC particles; 0.00, 0.25, 0.50, 0.75 and 1.00 were
mechanically blended with SAC and SnCu lead-free solder. There were two phases
involved. The first phase was investigation on the bulk composite solder properties and
the second phase was investigation on the as-soldered composite solder connection. The
wettability result showed the smallest contact angle for SnCu-SiC which is 18.60
degrees with 0.75 wt.% of SiC. While the smallest contact angle for SAC-SiC which is
20.00 degrees with 1.00 wt.% SiC. The optimum density value for SnCu-SiC and SACSiC
were 7.162 g/cm3 and 7.274 g/cm3 respectively when 0.75 wt.% of SiC. The
hardness values for SnCu-SiC samples was 13.0 HV starting at 0.75 wt.% to 1.00 wt.%
of SiC addition while SAC-SiC reach the maximum value 18.6 HV at 1.00 wt.% of SiC
addition. The shear strength for SnCu-SiC reach 14.95 MPa as an optimum value with
addition 0.50 wt.% of SiC. After that, the value decreased until the addition 1.00 wt.%
of SiC. The optimum value of SAC-SiC shear strength, 17.79 MPa was reached with the
addition 0.50 wt.% of SiC. After that the value was decreased when the SiC addition
has exceeded 0.75 wt.%. The electrical resistivity (ρ) of bulk SnCu-SiC and SAC-SiC
composite lead-free solders was measured with a four-point probe. The result showed
there only slightly affected by the addition of SiC for SnCu-SiC and SAC-SiC
composite lead-free solders. The value of electrical resistivity for SnCu-SiC and SACSiC
composite solder are decreasing when 0.75 wt. % and 1.00 wt. % of SiC particles
were added which is their value is 1.18 μΩ.cm, 1.12 μΩ.cm, 0.88 μΩ.cm and 0.81
μΩ.cm respectively. As overall, the result detailed in this work indicate that the addition
of SiC particles into SnCu and SAC based lead-free solder able to enhance their
physical and mechanical properties
Taguchi Method for p-MOS threshold voltage optimization with a gate length of 22nm
Get PDFLink to publisher's homepage at http://ijneam.unimap.edu.my/This paper describes the virtual design of a 22nm gate length p-type metal oxide
semiconductor, PMOS. Silvaco, TCAD tools were used to fabricate the device design and to
characterize the device’s electrical properties. Fixed field scaling rules are applied to obtain
the transistor’s electrical parameters set by ITRS 2013. In order to take the challenges that
arise in the fabrication of nano-sized transistors and enhance their performance, advanced
and novel technologies are applied. Using the statistical modelling of L9 Taguchi
methodology, the development process is primarily focused on the tool's edge voltage. Four
parameters have been divided into three distinct steps in order to conduct nine different
experiments. The final confirmation result indicates that VTH is closer to the nominal value
-0.206V following optimization techniques. This matches the ITRS 2013 requirements for
high performance. This paper examines the design of a p-MOS double gate containing a layer
of graphene as it is known to have a high mobility valu