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Development of aerobic granular sludge using industrial latex wastewater
No full textDoctor of Philosophy in Environmental EngineeringAn attempt of developing aerobic granules using industrial latex wastewater sludge was conducted. Optimization of cycling time were investigated and assessment of the effect of fluctuating organic loading was performed. Subsequently followed by investigation of physical characteristics of a stable aerobic granules under inconsistent and constant organic loading. Finally, aerobic granular sludge produced was then characterized by a height to diameter ratio (H/D) of 2.7 and 14. Experimental
investigation was conducted in sequencing batch reactors R1, R2, R3 and R4 with
cycling time of 4 hours after selection of cycling time was conducted based on
preliminary investigation. Four batches of experiment were performed to support the
objectives of this study. Similar size of sludge flocs was inoculated to all four reactors
with reactor configuration of 2.7 and 14 together with various organic loading rate. R1
and R3 was introduced to real latex wastewater with varying chemical oxygen demand
(COD) loadings from as low as 0.01 to 0.28 kgCOD/m3/d. However, granules in R1
were cultivated with superficial air velocity (SAV) of 4.25 cm/s, whereas granules R3
utilized SAV of 1.1 cm/s. R2 and R4 was fed with synthetic wastewater with consistent
COD loadings of 0.07 kgCOD/m3/d but with different application of SAV. All four
reactors achieve granulation, although granules developed in R1 and R3 is bigger and
denser than in R2 and R4. But when compared to granules grown in R1 and R3, R2 and
R4 granules were less compact and smaller in size. R2 and R4 granules can reach
granule size of 0.2 to 0.6 mm within 210 days, compared to R1 and R3 granules that can
only developed up to 4.75 mm within 150 days. This result shows significant difference
between R1 and R3 with R2 and R4 granules, and that COD loadings appear to be a
crucial factor for complete granulation. When R1 granules were compared to granules
in R3, an apparent difference of granules characteristics were observed with a high
average settling velocity (SV) value in R3 than in R1. On the other hand, R2 and R4,
displayed unstable development of granules throughout the study but stable reactor
performance after formation of granules. Utilization of a constantly low organic loading
rate (OLR) does not seem to favour a stable granules formation, although high height to
diameter ratio was applied to enhance the SAV within the reactor in order to intensify
shear force optimizing the formation of a more stable and compact granules
Fabrication and characterization of tissue engineering scaffold based of nanohydroxyapatite - local rice starches
No full textMaster of Science in Biomedical Electronic EngineeringBone tissue scaffold had been ventured for over the decades as a solution for bone failure and trauma. Starch is the most common natural polymer that has been used as a biomaterials and a good candidate for scaffold fabrication as there are many resources of starch in Malaysia. Native starches may contribute differently in their structure in terms of the amylose content, interactions between granules, swelling ability and solubility in which those differences can be mainly due to the botanical origin. In Malaysia itself, there are various resources of rice starches. No research yet has been performed on the application of Malaysian rice starch as a bone tissue scaffold. Balik Wangi, Bubuk Wangi, and Bario rice starches were used to fabricate the scaffold via solvent casting and salt
leaching technique. These three types of rice starch originally from Sarawak, Malaysia.
From the study, the porosity and the density were examined via liquid displacement test
and it was found the higher the starch percentage results higher porosity percentage. Here,
the dielectric properties were obtained via the values of dielectric constant and dielectric
loss which are another type of indirect measurement to study the porosity of the scaffolds.
The porosity has the value of dielectric constant and loss air matrix whereby this air
matrix is represented by the pore in the scaffold. The morphologies and microstructures
were evaluated by using Scanning Electron Microscopic (SEM) and showed the
increasing pore size as increasing the starch percentage. The Young’s modulus is obtained
to study the mechanical strength of the scaffolds where Balik Wangi rice starch-nHA
scaffolds have the highest value of young’s modulus due to fibre content in the rice.
Whereas, the interaction of the starch and hydroxyapatite blends were analyzed via
Fourier Transform Infrared Spectroscopy (FTIR). Lastly, the crystallinity structure for all
the rice starch-nHA scaffolds is studied via the X-Ray diffraction analysis and basically
hydroxyapatite dominate the crystalinity structure of the scaffold
Wireless Rogowski coil sensor based on partial discharge detection signal for on-line condition monitoring in the medium voltage power cables
No full textDoctor of Philosophy in Electrical Systems EngineeringPartial discharge (PD) measurement provide a valuable information for assessing the insulation health in high voltage (HV) power system. In this research, a novel wireless Rogowski coil (RC) sensor based on PD detection in the medium voltage (MV) power
cables is presented. This research is divided into three sections which are RC sensor development, pre-filtering technique and wireless integration. A series of investigations on sensitivity and bandwidth for four types of RC sensors was demonstrated. The
prototype development first was carried out with the assistance of SolidWorks 3 dimension (3D) computer aided design (CAD) software and MakerBot 2X 3D printer. Subsequently, the sensors were modeled and simulated using Electromagnetic Transient
Program-Alternative Transient Program (EMTP-ATP) software environment based on
the lumped parameter identification. A single-end measuring technique was used as an
on-line PD monitoring system on the three-phase medium voltage underground cross-link
polyethylene (XLPE) insulated power cable with a 240 mm2 nominal area copper
conductor. In order to verify the simulation results, an experimental measurement was
carried out. This experiment was repeated concurrently for each design of the RC sensors
and the precise selection for the best sensor is paramount. In this case, the results indicated
that rectangular geometrical shape performed better with regard to the detection of the
PD signal. The rectangular shapes of RC sensor has been selected in order to compare
with the conventional RC sensor. Double-end technique measurement has been used
where two of RC sensor is placed on the certain distance to analyse the propagation
velocity and arrival time of PD signal captured by the sensor based on the different size
of XPLE power cables. The analysis on accuracy of double-end and multi-end PD
location technique have been conducted. The results between double-end and multi-end
technique have 0.138 % and 0.026 % percentage error of PD location respectively. An
experiment has been conducted in order to evaluate the effect of unshielded, shielded RC
sensor and terminating resistance, . The is a part of parameter which can improve
the performance of RC sensor. An operational amplifier (op-amp) and active Butterworth
high-pass filter which has been designed using Sallen-key topology that is used to amplify
and suppress the noise of output signal from RC sensor in the second section. The
integration of RC sensor into wireless communication system has been discussed in the
final section. High speed analog to digital converter (ADC) device is required to sample
the PD signal due. However, the conventional ADC in the market is expensive in high
speed rate. Thus, Sigma-Delta (ΣΔ) ADC topology is developed in Altera DE0-Nano
board. Peak detection with threshold technique is introduced in this section. Then, the
data transmitted wirelessly to the server unit using radio frequency (RF) module as a
transceiver and Altera DE2-115 board is used as a server unit. In order to achieve the
accurate digital sampling of high frequency PD signal, the N-bit resolution is paramount.
The finding of this analysis, 4-bit resolution is selected in this research as the best
resolution for the ΣΔ ADC to sampling the PD signal
