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Antimicrobial and antioxidant activities from leaves and roots of (Elephantopus Scaber L.) extracted using different solvents
No full textMaster of Science in Bioprocess EngineeringMedicinal plants are used traditionally in treatment of various kinds of diseases since time
immemorial. The present study was carried out to evaluate the antimicrobial and
antioxidant activities of roots and leaves of Elephantopus scaber by using different
solvent (ethyl alcohol ,acetone and water). The ethyl alcohol, acetone and water extracts of
the roots and leaves were subjected to phytochemical analyses, which revealed the
presence of alkaloids, phenols, flavonoids, saponins, steroids, tannins, coumarins,
quinones and glycosides in most of the selected of roots and leaves useing different
solvents. Ethyl alcohol, acetone and water extracts of roots and leaves were investigated
for in.vitro.antimicrobial activity against Escherichia coli, Salmonella typhis, Klebsiella
pneumonia, Streptococcus pyogenes, Staphylococcus aureus, and Candida Albican by
well diffusion method using different concentrations (20, 40, 60, 80, 100)mg/ml. Bioassay
data obtained from the active extracts and oils were subjected to statistical analysis of
variance (ANOVA). Treatment means showing significant difference (p ≤ 0.05) were
separated using Student-Newman-Keuls test (SNK). Ethyl alcohol and acetone extract of
roots showed promising antimicrobial activity against all test organisms. Ethyl alcohol
extract of root gave a significant effect activity against all test organisms compared with
the other sample. Ethyl alcohol extract of leaves was also higher compared with the
acetone extract of roots for a concentrations of 100 and 20mg/ml. The water extract of
leaves has a weak activity against all test organisms and did not inhibit the growth of
Klebsiella pneumonia for a concentrations of 100mg/ml but at a concentrations of
20mg/ml did not inhibit the growth of all test organisms. The Minimum inhibitory
concentration (MIC) of the roots and leaves extracts by using different solvent were also
determined against different test organisms. The MIC value of roots and leaves extract
ranged from 100 mg/ml to 500 mg/ml. The ethyl alcohol, acetone and water extract of
roots and leaves were selected for possible antimicrobial activity. The antimicrobial
activity was studied against six microorganisms namely Escherichia coli, Salmonella
typhis, Klebsiella pneumonia, Streptococcus pyogenes, Staphylococcus aureus, and
Candida Albican. It was found that ethyl alcohol extract of roots showed height influence
against Escherichia coli, Salmonella typhis, Streptococcus pyogenes, Staphylococcus
aureus, and Candida Albican but less effective against Klebsiella pneumonia. The water
extract showed a weak effect against all tests organisms and did not has any effect against
Klebsiella pneumonia. The roots and leaves extract from Elephantopus scaber using
different solvents to extract were evaluated for antioxidant activity by using DPPH method
using a different concentrations (1, 10, 20, 30, 40, 60, 80, 100) μg/ml. The results from the
analysis were compared with ascorbic acid as standard
Thermo-mechanical properties of Napier particles filled polyester polymer
No full textMaster of Science in Mechanical EngineeringIn recent years, the incorporation of natural fibers as reinforcing agent in polymer composite has gained increasing interest which enhances optimal utilization of natural resources and particularly of renewable resources. Natural fibers have proven to be suitable reinforcement materials for composite; combination of good mechanical, high electrical (insulating), impact resistance, good thermal and acoustic insulating properties and with environmental advantages such as renewability and bio-degradability, comparable to synthetic fiber reinforced polymer. Hence, for these reasons it has not been surprising that the use of natural materials in the production of composites has gained significant importance in various fields from household articles to automotives. This research is to use Napier grass as filler contents on the properties of Napier filled polyster polymer are to
enhance the elastic modulus, strength and toughness without sacrificing the strain to failure and thermal stability of the polyester. The effects of polyester resin with different Napier filler contents i.e 1, 3 and 5wt.% had been studied. Specimens were prepared based on ASTM D695 and ASTM D638 standards for compression and tensile test respectively.
However, proliferation used Napier filled polyster polymer have not yet reached their full potential as advanced engineering materials due to several hindrances such as agglomeration particles and poor dispersion dispersion introducing premature failure of the system, weak filler-matrix interface bonding reducing the stress transfer and the understanding of the dispersion of Napier fillers in matrix system. The main challenges is to achieve exfoliation of large stacks of Napier fillers into matrix system keeping in mind the manufacturing process limitations. Various methods of dispersion ( hand mixing, water shaker bath and hot plate stirrer) be investigated to achieve the best mix hence development of a stiffer and tougher matrix systems which improving the resistance to crack initiation and propagation. Napier filled polyester polymer samples were performed at room and elevated temperatures (Room temperature (25 °C), 35 °C, 55 °C and 75 °C) to study the effects of temperatures on polymers. In this research, the results show that the mechanical properties of compression and tensile test of Napier filled polyester were improved in
modulus with increasing the filler content. Thermal stability of the Napier filled polyester polymer increased as the Napier filler content was increased. The samples prepared by the hot plate stirrer(rotary mixing) method yielded the highest strength compared with manual hand mixing and water shaker bath (shear mixing). The temperature has even a more significant effect. It was observed that as the temperature decreases the material becomes brittle, has higher stiffness and fails at lower strains. High temperatures have the opposite effect, in that,as the temperature increases the material loses stiffness and becomes more
ductile. This result suggests that the Napier filler introduced additional mechanisms of energy absorbtion, improving the mechanical properties
Development of an improved microgrid-centralize power sharing scheme using fuzzy logic controller
No full textMaster of Science in Electrical System EngineeringA microgrid is a local energy grid with control capability, which means it can be connected to or disconnected from the traditional grid and operate autonomously. Recently, the droop control techniques are widely used to solve the problem of load sharing in microgrid system. These techniques have been improved to resolve the rising issues such as system stability and power sharing. Although the improved droop techniques improvise the stability of microgrid operations, however the power sharing
performance still not optimized and can be further improved. This thesis focuses on improving power sharing for parallel connected inverters in an islanded microgrid. A centralized power sharing scheme that utilizes Fuzzy Logic Controller (FLC) is proposed to improve the power sharing among parallel connected inverters in AC islanded microgrid. This proposed technique is implemented to control three parallel connected single-phase inverters in a microgrid. Central controller is used to process active and reactive output power information from all inverters and calculates the active and reactive output power references for each inverter based on the desired ratios of their output powers. The information from centralized control are then process by the FLC at each inverter to adjust the output voltage to an appropriate value to achieve the required power sharing. Several simulations have been conducted to verify the performance of the proposed power sharing scheme
Crushing behaviour of glass fibre/epoxy composite pipes: the effects of winding angles, ageing, and temperatures
No full textMaster of Science in Mechanical EngineeringThe effects of hydrothermal ageing on the crushing behaviour of glass fibre-reinforced epoxy (GRE) pipes are discussed. Pipes with three different winding angles (±45°, ±55°, ±63°) were manufactured using the filament winding process. Prior to the
compression tests, the pipes were hydrothermally aged in tap water at a constant temperature of 80°C for periods of 500, 1000, and 1500 hours. Uniaxial compressive tests were conducted on the virgin and aged samples using a universal testing machine
(UTM, Shimadzu) in accordance with ASTM D695-10. The tests were also performed at temperatures ranging from room temperature (RT) to 45°C, 65°C, and 95°C to study the response of the pipes at elevated temperatures. The temperatures were selected based on the results of differential scanning calorimetry (DSC) tests, where the value of the glass transition temperature (Tg) was determined to be 66.39°C. Scanning electron microscopy (SEM) images were captured and the relationship between the ageing period and strength of the GRE pipes was determined. The results indicate that the strength of the GRE pipes significantly decreases with increase in the temperature where pipes compressed at RT produced the highest strength while the lowest is at 95°C. The same could be observed for ageing periods where virgin pipes shows the highest compressive strength and the strength degrades as the ageing period was extended. The strength of GRE pipes increases as the winding angles decrease. ±45° winding angle has the highest strength followed by ±55°, and lastly ±63°. The experimental results were also compared with theoretical analysis obtained from Berbinau’s based model and the experimental values are found to correlate well with the predicted values
New empirical formula for reduction factor of head garment
No full textDoctor of Philosophy in Product Design EngineeringPressure garment is one of non-surgical method in pressure therapy treatment, which uses pressure as healing mechanism for hypertrophic scars caused from burn injuries. Previous studies proposed a fabrication method based on the modified Laplace`s Law to predict pressure outputs. From the Laplace`s Law, reduction factor is calculated using parameters of modulus elasticity of the fabric, body circumferences, and the targeted pressure. However, most of the previous studies conducted based on lower and upper limbs body parts (arms and legs) which consist more like cylindrical shapes with limited studies conducted for head segment. The aim of this study is to investigate the effectiveness of current methods used for pressure therapy treatment at facial area. Based on investigation and analysis from the current methods in terms of pressure performances, a new
fabrication method of head garment is introduced which capable to produce optimum pressure needed for the treatment. This study uses digital design approaches such as 3D scanning, computer aided design and additive manufacturing in design and development phases. Based on the previous reduction factor equation from literature, the produced head garment was tight and not suitable for the treatment. Hence, a new head garment fabrication method is proposed based on empirical approach to determine the reduction factor at particular circumferences of the body parts
Performance analysis of two dimensional wavelength/time OCDMA system for optical network
No full textMaster of Science in Communication EngineeringThe major interference factor in an Optical Code-Division Multiple-Access System (OCDMA) is the noise in the form of Multiple Access Interference (MAI), which induces the occurrence of Bit Error Rate (BER). Phase Induced Intensity Noise (PIIN) is the
dominant noise in the receiver that is closely related to MAI. The use of an ideal code with minimum cross-correlation will mitigate MAI, reduce PIIN, and expand code scalability. Many codes have been proposed for One-Dimension (1-D) systems. These
involve exploiting the wavelength or time resource. However, some of these codes have fixed or zero cross-correlation property which cancels out the MAI. However, the performance is still affected by the PIIN. 1-D codes need a very long code length when
there is a high cardinality. Therefore, the objectives of the thesis are, first, investigate the OCDMA codes to enhance the performance and decrease the required code length, such as the 2-D Perfect Difference (PD) code, and Wavelength/Time (W/T) 2-D Modified Double Weight - MDW), second the implementation and analysis of two-dimensional (2-D) codes for an OCDMA system via simulation. The thesis starts with an explicit
construction of an incoherent 2-D MDW OCDMA system with the allocation of
wavelength and time dimensions resource to achieving performance goals and design
parameters. The study of the properties of the code include a consideration of the
scientific functions of the performance by analyzing various parameters such as the output
signal spectrum and BER versus the length of the fibre, the number of users, data rate,
the use of Avalanche Photo-Detectors (APD) in the receiver, and the effective received
power ( srP ). Secondly, the 2-D MDW OCDMA code is designed in simulation
Synthesis and characterization of a two-step reduced Graphene Oxide for antena applications in the microwave resime
No full textMaster of Science in Materials EngineeringThis thesis presents the development of a two-step reduced graphene oxide that is to be implemented as the radiating element for a patch antenna. The two-step reduced graphene oxide is prepared with graphite powder and is oxidized using the Tour’s method. The graphene oxide produced from this procedure is cleaned and neutralized before microwave irradiation procedure is carried out to begin the reduction process, by which oxygen containing functional groups are removed from the material. The second step of the reduction process consists of using the strongest hydrohalic acid, hydroiodic acid, to reduce graphene oxide in a reflux setup. The two-step reduced graphene oxide and its precursors are characterized using Field Emission Scanning Electron Microscopy (FESEM), Thermogravimetric analyzer (TGA), Ultraviolet-Visible Spectroscopy (UVVis), Fourier Transform Infrared Spectroscopy (FTIR), 4-Point Probe Conductivity Test, X-Ray Diffraction analyzer (XRD), and Energy Dispersive X-Ray analyzer (EDX). The results of the two-step reduction process yielded a reduced graphene oxide with a net conductivity measured at 4.8 x 102 Sm-1. The measured resistivity and electrical conductivity results were higher in the two-stepped method than any measurement yielded from its precursor materials. This thesis explains the effects that microwave irradiation and chemical reduction has on the degree of reduction and the overall structure of reduced graphene oxide. The two-step reduced graphene oxide was used as the radiating element in a microstrip patch antenna to determine the antenna performance in
the microwave region
Development of a rapid and accurate system to differentiate Malaysian honey samples using UV and color image
No full textMaster of Science in Mechatronic EngineeringMalaysia is a country rich with natural forest resources such as spices, herbs and honey. Honey and honey-based products in Malaysia is gaining popularity as a result to the healthy lifestyle promotions by various groups including the government. This leads to the business opportunities to provide honey and its derivatives into the market. However, this also creates another problem in determining the quality, and types of honey offered by the market. This is because different honey types, for example, have different properties, which may be desirable for different purposes, and market segments. At the moment, the methods in determining the botanical origins of honey are all laboratory-based, which may be tedious, not portable, involve chemical
synthesis, time consuming and required expert personal. This research introduces a more efficient approach using UV for honey classification. This research work also shows that a low-cost approach using RGB digital camera, can also be used for the
same purpose. In addition to that, the work introduces the idea of fusion using the two approaches and shows an improvement in classification. The work presented the classification of the honey based on two characteristics from three (3) types of local
honey, namely the antioxidant contents and colour variations. The former uses the UV spectroscopy of selected wavelength range, and the latter using RGB digital camera. Principal Component Analysis (PCA) was used for both methods to reduce the
dimension of extracted data. Support Vector Machine (SVM) was used for the classification of honey. The assessment was done separately for each of the methods, and also on the fusion of both data after features extraction. The overall classification of
the fusion method improved significantly compared to single modality. Honey classification based on the fusion method was able to achieve 94% accuracy. Hence, the proposed methods have the ability to provide accurate and rapid classification of
honey products in terms of its origin. The proposed system can be applied to the Malaysian honey industry and further improve the quality assessment and provide tracebility
Wavelet based image denoising using raspberry PI
No full textMaster of Science in Embedded System Design EngineeringThere has been a huge demand for effective image restoration techniques since the increase in the production of the digital movies and images. No matter how good cameras are, an image improvement is always desirable to extend the image property and view. In image processing, it is very important to obtain precise images. Low image quality is an obstacle for effective feature extraction. Therefore, there is a fundamental need of noise reduction from images. current technique in reducing noise is efficient however focus on pc or desktop based processing. The drawback is the relatively high computational cost.
This modification is done to non-local means algorithm results in improved accuracy and computational performance. There are currently a number of imaging modalities that are used for study of image processing. The aim of image de-noising in image processing is to clear the unwanted noise from the noisy image and implement an effective image denoising algorithm with the help of the Python programming language. Improve the processing methods by implementation of Non-local means and wavelet hard thresholding. Raspberry Pi-based system is used to implement image denoising. In this
research, Gaussian noise is used, because noise property similar to a normal distribution.
Both method has been implemented in Raspberry pi environment using Python 2.7.9 with
Open CV 3.1.1. By used on both methods there are different result seen from the output.
Non-local means (NLM) produce smoothen image and less noise, while wavelet hard
thresholding have less error compared to Non-local means. The average difference
between the PSNR by the hard threshold method and the PSNR by the NLM method of
the images taken as an example of the image Lena the difference in succession according
to the use of sigma 25 is 1.4711, in image Pepper 2.2303, in image Boat 2.0481. In term
of processing time NLM is faster than wavelet hard thresholding. Both algorithm perform
well in Raspberry P
Development of gesture database for an adaptive gesture recognition system
No full textMaster of Science in Mechatronic EngineeringHuman gestural motion is one of the areas in studying human behaviour regardless the physical capability and intellectuality of each individual. In this research, the focus is to investigate human physical characteristics which contribute to the performance of
gestural motions. Every person has different body structure and physical distinctive that can be determined by calculating the person’s body mass index (BMI) and measuring the size represented by the weight an geometrical gestures. The geometrical gesture databases are developed based on human body characteristic features. These gesture databases are utilized to recognize and
identify an unknown gesture by gathering some information of human features for
further analysis. A motion capture system was used to capture gestural motions. Three
dimensional data obtained from motion capture system are analysed, classified and
stored in the gesture database. The resampling algorithm is developed to diminish the
excessive movement information which to be used in the represented form. Principal
Component Analysis (PCA) is used to reduce dimension of data and classify the gesture
data. PCA classifies three groups of people based on gestural motions of subjects. For
further clarification, data inside the group database were tested for similarity and
dissimilarity measured using Jaccard Similarity Measure; the result of total average is
90.8% dissimilarity of all five geometrical gestures between group #1, group #2 and
group #3 for all the three axes: X-axis, Y-axis and Z-axis. Consequently, adaptive
gesture recognition is introduced to select the suitable database especially for
identifying unknown gestures inserted into the system. The result of recognition shows
that recognition of individual database is 86.5%, group database 83.7% and the lowest
is recognition of universal database which is 82.8%. The experimental result shows that
the group database is preferable for an adaptive gesture recognition system