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Now showing 1 - 20 of 3249
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    0.13 𝛍𝒎 cmos class f rf power amplifier for iot application
    (2019-05-01)
    Liew, Xin Ye
    Internet of Things (IoT) industry keep growing in recent years. The design of RF power amplifier with high efficiency is thus crucial to reduce power consumption needed for data transmission which is high in capacity and speed. This project is a 0.13 μm CMOS Class-F Radio Frequency (RF) Power Amplifier (PA) which is designed for 2.45 GHz IoT application. The power amplifier design in this project consists of 3 parts including Input Impedance (IIP) match circuit, Class-F harmonics termination circuit and Output Impedance (OIP) match circuit. Smith chart for RF and Cadence software analysis tools are used in this design. For Bluetooth Low Energy (BLE), at least 4 dBm of output power is needed for signal transmission in BLE standard. In terms of performance, this PA design has power gain of 5.79 dB and output power of 5.79 dBm at operating frequency 2.45 GHz for the maximum Power Added Efficiency (PAE) of 31.62% with Output Third Order Intercept Point (OIP3) of 8 dBm. The maximum Output Third Order Intercept Point (OIP3) for this design is 15.7 dBm. At output power of 4 dBm (BLE standard), the PA’s power gain is 7.34 dB with PAE of 30% and OIP3 of 13 dBm. At the operating frequency of 2.45 GHz, the PA exhibits stability k-factor, 𝐾𝑓 value of more than 1 and thus the PA is unconditionally stable. Besides, the PA shows S-parameters performance of -19.25 dB for 𝑆11 and -13.97 dB for 𝑆22. These performances of PA are achieved at power supply of 1.2 V.
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    1.5-Bit stage analogue-to-digital converter (ADC)
    (2023-08)
    Ch’ng, Ooi Keat
    This report presents the design of 1.5-bit stage Analogue-to-Digital Converter (ADC). In this project, with some assumption considered, the minimum open-loop DC gain, AOL required for this project is calculated as 40dB. Meanwhile, the minimum unity gain frequency, fu of the OTA must be at least 16.0MHz as the ADC designed in this project will be clocked at 8MHz. Average power consumption of the main OTA is expected to be less than 40mW. Silterra 180nm process technology is used in this work. The architecture of 1.5-bit stage ADC mainly consists of an operational transconductance amplifier (OTA) as the core element. Generally, the 1.5-bit stage is made up of a 2-bit comparator, a digital logic circuit and a residue amplifier. The main function of the comparators is to emonstrate that an input signal is either larger or less than a predetermined reference voltage. The digital logic circuit serves as switches to allow the residue amplifier to function by receiving a 2-bit digital input from the comparator. Based on the results obtained, the main OTA in this project has specifications such that 45.0dB for the open-loop DC gain, 470.11MHz for unity-gain frequency, 79.52° for phase margin, and 27.117mW for average power consumption for the main OTA. In short, all the specifications for this main OTA have all achieved the minimum requirement of the main OTA design. The three blocks for the overall design of 1.5-bit stage ADC, which are the 2-bit comparator, digital logic circuit, and lastly the residue amplifier, are all carried out their specific. functions successfully as all of them are verified throughout the testbench simulations with the desired outcomes.
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    10-bit digital-to-analog converter (dac) using partial binary tree network (pbtn) dynamic element matching (dem) approach
    (2019-06-01)
    Tan, Zi Jun
    Digital-to-Analog converters (DAC) are an important element in many digital systems which demands high-performance data conversions. Due to factors like shrinking supply voltage and budget constraint, DAC highly relied on matched components to perform data conversion. However, matched components are nearly impossible to fabricate, because mismatch errors always occurred between designed and actual component value. One of the techniques to overcome the effect of mismatched components error is to use Dynamic Element Matching (DEM) method. This method randomizes the digital input codes before entering DAC block, making the time of each component position nearly equal. The drawback of this design is, it would suffer from excessive hardware complexity and causes glitches at the output signal. In this research, the DEM algorithm used is known as Partial Binary Tree Network (PBTN) algorithm. PBTN reduce the complexity of the circuit and produce an output signal with fewer glitches. In this research, the ideal Operational amplifier (Op-Amp) used to magnify the output current is replaced with an Op-Amp built by transistors. This thesis reports the simulation of 10-bit 1-MSB PBTN DAC using a non-ideal operational amplifier with DNL of -0.182979 LSB, INL of -0.959287 LSB and power consumption of 1.108 mW.
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    180° hybrid coupler implemented with 2x2 butler matrix
    (2019-06-01)
    Halmy, Nor Amylia Mohd
    Hybrid coupler is a four-port device where a directional coupler is designed to split power equally between two ports. Hybrid coupler can be used to decouple and increase the isolation between antenna ports. In this project, it is focus on how to design 180° Hybrid Coupler implemented with 2x2 Butler Matrix by using CST. The concept of transforming branch-line hybrid coupler into coupled-resonator network is presented in this project. The proposed of hybrid coupler with additional method with 2x2 Butler Matrix is to improve the isolation, size reduction, better terms of low production cost and good return loss. This project is focused on how to reduce the size of hybrid coupler so that it will obtain good S-Parameters. This design is fabricated using RO 4003C printed circuit board with dieletric constant, 𝜀(, 3.55 mm, thickness of substrate, H, 0.81 mm and thickness of copper, t, 0.035 mm. The design need to be operated at 2.4GHz. From the simulation and measured results, the 180° Hybrid Coupler implemented with 2x2 Butler Matrix nearly met the entire requirement needed such as return loss which is less than - 10 dB, isolation loss is nearly less than -5 dB. However, the isolation between ports is in the range frequency of 2.39 GHz to 2.54 GHz. It is still acceptable because the performance is not affected.
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    20 kwe biomass downdraft gasifier system
    (2005-03-01)
    Ishak, Mohd Asrul
    A small scale downdraft gasifier that has producing 20kW biomass generator had been set to provide electrical power for the rural areas have been developed. The downdraft gasifier is erected in the laboratory at the School of Mechanical Engineering, Universiti Sains Malaysia (USM). In this research, gasification system in used is gasifier in lower flow with a wood as a biomass sources. Many modification were made during installation and this experimented to make it suit with surrounding condition and to improve the performance of the system. Experiments have been performed of gasification of furniture wood as raw material. The system performance of the gasifier had been determined by finding the efficiency of the system, moisture content and diesel displacement. The system of the downdraft gasifier also involved the development of power absorbing system using 24 kW electrical loading as heating element has been successfully done. The overall efficiency of the system at full speed is 3.64% to 15.75% and minimum speed is 4.16% to 21.5% depending on the electrical load used to absorb the power from the generator. Air flow rate of the producer gas also increase with the speed of generator. The moisture content of the wet wood is quite small but still in the range.
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    2–18ghz radar pencari arah
    (2006-11-01)
    Hussin, Mohd Ridhuan
    This report presents the design of radar direction finder which will be use to detect the receiving signal in the frequency range of 2GHz to 18GHz. This range of frequency is commonly use by the military for their operations. This system is design with the combination of several parts such as receiver antenna, low noise amplifier circuit, mixer down converter circuit, varactor tuned oscillator circuit, band pass filter circuit, RF to DC voltage converter circuit, amplifier circuit, analog to digital converter (ADC) circuit, digital to analog converter (DAC) circuit and finally the 8051 microcontroller trainer board. In this system, the receiver antenna that will be use is from the antipodal vivaldi antenna type. Its need exactly eight identical antenna to make this direction finder system to works well. Each design and simulation done in this project is using the software called HPADS. The control and process unit for this system is done by the 8051 microcontroller.
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    3d networked virtual representation
    (2009-04-01)
    Tan, Hong Ping
    Three dimensional (3D) virtualization has been a popular method to observe and present data and simulation results. Although many robotic applications have applied 3D virtualization technology for simulation, there is not much applications which incorporate 3D technology into computer networking to develop a networked virtual environment (net-VE) with teleoperation ability. This project aimed to realise such system, where multiple users able to control and view the virtual mobile robots, in addition, able to teleoperate a real mobile robot through the virtual environment. This project presented the system, 3DVR©, which has all the features of a net-VE system with teleoperation function. 3DVR© is being developed using Python scripting language, and Panda3D® engine for 3D virtualization. The implementation of 3DVR© shows 3D virtualization of 3D models and environment in a graphical user interface (GUI) with functions in aiding the users to view and navigate around the virtual environment. There are four operation modes in 3DVR©; which are local virtual robot simulation, local real robot teleoperation, mobile robot teleoperation through local area network (LAN), and mobile robot teleoperation through internet. The four operation modes are successfully demonstrated with virtual mobile robot models and the results obtained are promising.
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    3D rock slope stability assessment using anisotropic materials model
    (2020-10-01)
    Nagendran, Sharan Kumar
    Rock anisotropy is a well-known phenomenon relating to the heterogeneity of rock mass. Nevertheless, its influence in geotechnical design, especially in rock engineering, is often ignored. Slope with certain modes of failure can be evaluated conventionally as well as numerically. For this study, the rock slope assessment was conducted numerically using 2D and 3D Limit Equilibrium Method (LEM) utilizing the Slide program by Rocscience. The fundamental roles of the discontinuities present in the study area were evaluated to study their influence on slope stability. Anisotropic material model was incorporated in the LEM analysis to investigate the presence of discontinuities. The measurement of discontinuity orientation in the rock slope by traditional scanline survey is time-consuming and challenging due to accessibility issues. Structure from motion (SfM) photogrammetry using Unmanned Aerial Vehicle (UAV) allows a quick and cost-effective way to do survey mapping for geotechnical assessment on rock slope compared to terrestrial laser scanner (TLS). Dense point cloud is exported to the CloudCompare tool for geological plane extraction. The stability of the rock slope was evaluated using the deterministic 3D and 2D Limit Equilibrium Method (LEM) using the geometry of the 3D rock slope system. In this study, the anisotropic material model was utilized to examine the Factor of Safety (FoS) results. Generalized anisotropic material model was used for incorporating the Generalized Hoek Brown criterion (rock mass), Mohr Coulomb (weak joint) and Barton Bandis criterion (weak joint). The rock mass and shear strength parameter for numerical analysis were determined via destructive and non-destructive tests such as Uniaxial Compressive Strength (UCS), Schmidt Hardness and JRC estimation using Barton comb. The discontinuities extracted are reliable and accurate as they are within 10° of the data measured manually. By using discontinuity data, the kinematic analysis shows that the rock slope has 12.80% of risk in planar sliding, 6.67% in wedge sliding and 1.93% in flexural toppling. Mean dip / dip direction obtained was used as an input for the value of the anisotropic plane where it causes a weakness in the strength of the rock slope. The results of FoS shows that rock slope without anisotropy model is stable and analysis using anisotropic material model predicts that the slope may fail. 3D slope stability analysis was able to identify the weakest spot easily rather than to assume based on the results of 2D slope stability assessment which might represent the whole rock slope. 3D rock slope stability assessment proves to be very cost-effective method for remedial work whereas in 2D stability assessment, wrong cut-sections may provide inaccurate FoS. This study presents the approach of using anisotropic material model utilizing basic rock testing and field observation data to analyse the rock slope stability.
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    3D-CT craniofacial morphometry among Malay down syndrome and normal subjects in Hospital Universiti Sains Malaysia
    (2018-05)
    Al-Shammari, Haider Ali Hasan
    This is the first three-dimensional computed tomography (3D-CT) study, as far as the author is aware, of the craniofacial morphology of Malay Down Syndrome (DS) subjects. This information is intended to increase understanding of the DS quantitative phenotypic features in order to improve the strategies required with the management of these patients. To study the size of the craniofacial structure which include linear and angular measurements in Malay DS subjects and to compare them with normal subjects. Additionally, sexual dimorphism and age differences of both the DS and normal subjects were also investigated. This is a cross sectional 3D-CT study on 240 Malays (Normal = 180, DS = 60) aged between 0 to 35 years old. The initial 2D formats were then reconstructed into 3D utilising Mimics V17.0 software. Linear and angular dimensions of craniofacial structures were measured for each subject using consistent landmark definitions. Comparisons were made between DS and normal subjects, between the males and females and among selected age groups. The selected ages are children (0 to 6 years), pre-adolescents (7 to 12 years), adolescents (13 to 20 years) and adults (21 to 35 years). High reliability of the examiner in carrying out the measurements was detected with ICC values in the range of 0.8 to 1. Generally, each craniofacial region showed unique growth pattern as observed from infancy to adulthood. Most of craniofacial measurements in DS subjects showed smaller values than normal from infancy to adulthood. Sexual This is the first three-dimensional computed tomography (3D-CT) study, as far as the author is aware, of the craniofacial morphology of Malay Down Syndrome (DS) subjects. This information is intended to increase understanding of the DS quantitative phenotypic features in order to improve the strategies required with the management of these patients. To study the size of the craniofacial structure which include linear and angular measurements in Malay DS subjects and to compare them with normal subjects. Additionally, sexual dimorphism and age differences of both the DS and normal subjects were also investigated. This is a cross sectional 3D-CT study on 240 Malays (Normal = 180, DS = 60) aged between 0 to 35 years old. The initial 2D formats were then reconstructed into 3D utilising Mimics V17.0 software. Linear and angular dimensions of craniofacial structures were measured for each subject using consistent landmark definitions. Comparisons were made between DS and normal subjects, between the males and females and among selected age groups. The selected ages are children (0 to 6 years), pre-adolescents (7 to 12 years), adolescents (13 to 20 years) and adults (21 to 35 years). High reliability of the examiner in carrying out the measurements was detected with ICC values in the range of 0.8 to 1. Generally, each craniofacial region showed unique growth pattern as observed from infancy to adulthood. Most of craniofacial measurements in DS subjects showed smaller values than normal from infancy to adulthood. Sexual dimorphism was observed for linear and angular variables in both DS and normal subjects. The number of variables that showed sexual dimorphism increased from infancy to adulthood. Differences in size between males and females were not obvious during infancy as only a few variables showed significant differences. During preadolescent and adolescent stages, only some of the variables showed significant size differences between the sexes. Sexual dimorphism in the craniofacial region was most evident during adulthood with more variables displaying significant differences between the sexes. The majority of the craniofacial variables increased in size significantly from birth to 35 years of age in both DS and normal subjects. This study provides comprehensive description of the craniofacial dimensions of Malay DS subjects. This study has generated craniofacial reference data for DS and some additional normal data. These reference data is hoped to facilitate management of Malay DS subjects. Moreover, these information could also help maxillofacial, orthognathic, plastic and reconstructive surgeons, orthodontists, medico-legal experts and forensic scientists to perform objective and quantitative management, decide treatment strategies and assessment of treatment outcome. In addition, the size of craniofacial structures showed sexual dimorphism at most age categories. Gender consideration should be taken into account in clinical assessment and procedures which may affect the craniofacial complex. Furthermore, quantification based on 3D data provides new insights into craniofacial growth changes and morphology compared with conventional 2D approaches.
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    3d-printed hexagonal prism-shaped polylactic acid/chitosan/nanohydroxyapatite composites for heavy metal ion adsorption application
    (2024-08-01)
    Goh Chiu Bee
    The potential of 3D printing in wastewater treatment has been harnessed to design adsorbents for removing heavy metal contaminants. This research explores the potential of 3D-printed biobased composites for heavy metal adsorption in addressing limitations associated with conventional designs. Current 3D-printed filters for heavy metal removal often utilize block-like shapes (cubes or cylinders) which restricted the accessible surface area exposed to wastewater. This study proposes a novel approach by fabricating biobased scaffolds using fused deposition modeling (FDM). The unique design features hollow hexagonal prisms provide maximal surface area for the subsequently integrated chitosan/nanohydroxyapatite (CS/nHA) composite. Besides, the effect of pH and initial concentration on the adsorption capacity of the designed PLA/CS/nHA composites was investigated. The adsorption properties of the PLA/CS/nHA composite for copper (II) and cadmium (II) were tested by varying pH (3 to 6) and initial metal concentrations (20 mg/L to 100 mg/L). Copper and cadmium were chosen because of their high toxicity at trace levels. The concentration of heavy metal ions was measured using a UV-Visible Spectrophotometer (UV-Vis). The surface morphology and elemental compositions of PLA/CS/nHA composite were analyzed using field emission scanning electron microscopy (FESEM) equipped with energy-dispersive x-ray spectroscopy (EDX). Fourier Transform Infrared Spectroscopy (FTIR) was employed to examine the interactions between functional groups of adsorbents and heavy metal ions. The PLA/CS/nHA composite achieved a maximum adsorption capacity of 263.72 mg/g for Cu(II) at pH 5 and 213.34 mg/g for Cd(II) at pH 6. Notably, the adsorption capacity demonstrated a positive correlation with increasing initial metal concentrations. Cu(II) exhibited higher adsorption than Cd(II) due to smaller ionic radius and higher electronegativity. Both Langmuir and Freundlich isotherm models effectively described the experimental data, with the Freundlich model exhibiting a more dominant role. The involvement of hydroxyl, amine, and phosphate functional groups of CS/nHA in adsorption of Cu(II) and Cd(II) was confirmed by the FTIR results. Overall, the adsorption capacity of PLA/CS/nHA composite was enhanced significantly by the unique hexagonal prism design of the 3D printed biobased PLA scaffold. The innovative design with higher heavy metal removal capacity than conventional form (powder, beads, block-shaped) is expected to inspire future research in this field.
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    5.8 GHz printable microstrip patch antenna for WI-FI applications
    (2024-07)
    Liu, Zhi Qi
    Modern communication systems, including computers, mobile phones, wireless devices and other gadgets, can be connected to the Internet via Wi-Fi, a wireless networking technology. This paper describes a microstrip patch antenna for Wi-Fi applications. Among Wi-Fi technologies, microstrip antennas have received the most comprehensive attention. This research involves the design of a low-profile flexible microstrip antenna for 5.8GHz Wi-Fi networks. Microwave studio using computer simulation technology (CST). The performance of the antenna is evaluated by considering the antenna return loss, radiation pattern, bandwidth and Smith diagram. The return loss must be less than -10dB, and the bandwidth must be greater than or equal to 0.1GHz. In this experiment, the S-parameter of the simulated antenna at 5.8GHz is -25.297797dB, and the lowest value of the test antenna is -34.0859dB at a frequency of 5.876GHz. An antenna resonates at the desired frequency using a rectangular patch on a dielectric substrate, and sputtering machine is used to make the antenna. This report details the design, simulation and testing of a microstrip patch antenna in the 5.8GHz band for Wi-Fi applications. This paper discusses the theoretical background of microstrip patch antenna, design considerations for achieving 5.8GHz resonance and the design method chosen. The selection of materials is introduced. Finally, the testing process of the antenna is given, and the test results are analysed according to the simulation data.
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    65nm CMOS bandgap voltage reference circuit
    (2023-07)
    Low, Chee Weng
    Bandgap voltage reference is a circuit that produces a stable output reference voltage that is not affected by the variation of process, voltage and temperature (PVT). BGR is an essential and important component that is used in many applications such as power converters, flash memory controllers, PLL, LDO, A/D converters. In a bandgap voltage reference circuit, the output reference voltage is generated by the summation of two voltages (VPTAT and VCTAT) with opposite temperature coefficients. This voltage is then amplified and filtered to generate a stable output reference voltage that is relatively insensitive to the changes in process, temperature and supply voltage variations. In this project, TSMC 65nm CMOS Bandgap Voltage Reference Circuit is designed. A stable of output reference voltage of 1.23V with supply voltage of 2V is expected from the outcome of this project. Next, the phase margin of the two-stage operational amplifier should achieve larger than 45°. Temperature coefficient of the BGR should achieve lower than 30ppm/°C and power consumption lower than 300µW is expected. The workflow of this project starts from calculations of parameters of MOSFETs and passive components, schematic design of the two-stage operational amplifier and bandgap voltage reference circuits until pre-layout simulation of both schematic circuits. As the output from pre-layout simulations, the DC gain and phase margin of the op-amp achieve 73.04892dB and 84.63997° respectively while the output reference voltage recorded is 1.22847V ~ 1.23819V with 0.81% (± 10mV) of inconsistency for supply voltage from 2V to 4V. Next, temperature coefficient of 27.81ppm/°C is obtained for temperature ranging from 40°C to 125°C. Lastly, the power consumption of the BGR circuit is 298.1µW.
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    8 Bit Cmos Hybrid Digital-To-Analog Converter For Bluetooth Low Energy Application
    (2019-03)
    Rosli, Alia
    In the bluetooth low energy implementation, the digital-to-analog converters act as the bridge gap between digital signal processing chips, and power amplifiers that transmit analog signals. This thesis presents the design of a hybrid Digital-lo-Analog Converter( DAC) intended for RF transmitter in 2.45 GHz Bluetooth Low Energy (BLE) application by using CMOS 180 nm technology. The hybrid DAC design strategy is based on iterative scheme whose variables are adjusted in a simple way, minimizing the power consumption as well as area and also meeting the design specifications.
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    9th International conference on biosience, biochemistry & bioinformatics 2018.
    (2019)
    Transient receptor potential cation channel subfamily M member 4 (TRPM4) is overexpressed in activated B-cell-like subtype of diffuse large B-cell lymphoma (ABC-DLBCL) associated with poor survival. In this study, its functions in the disease and the potency of its inhibitor 9-phenanthrol were investigated. The biological functions associated with TR.PM4 mRNA expression were examined through Gene Set Enrichment Analysis (GSEA) in ABC-DLBCL cases (n=15). The cytotoxicity of 9-phenanthrol in three ABC-DLBCL cell lines (SUDHL2, OCI-LY3, OCI-LYIO) was tested at six different concentrations (0.0InM, 0.1 nM, InM, lOnM, 25nM, 50nM). GSEA results showed that cell cycle gene sets conferred the highest number of gene sets representing 42% (n=21/50) of the top 50 most significantly enriched gene sets ranked according to false discovery rate (FDR; all 50 gene sets had FDRO.OI), followed by DNA replication (n=8/50; 16%) and RNA processing (n=8/50; 16%), suggesting the roles of TRPM4 in cell cycle progression and cellular division of ABC-DLBCL. In terms of the cytotoxicity effects of 9-phenanthrol, the resulting GI50 for all ABC-DLBCL cell lines ranged from 19nM-41,88nM. In conclusion, TRPM4 is potentially involved in the cell cycle progression and cellular division of ABC-DLBCL cells, and the TRPM4 inhibitor 9-phenanthrol was cytotoxic against ABC-DLBCL cells.
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    A literature study of sabah sarawak peninsular Malaysia
    (2008-08-01)
    Loh, Swee Aun
    Nowadays, High voltage direct current (HVDC) is used to transmit large amounts of power over long distances or for interconnections between asynchronous grids and underwater or submarine transmission. It has become an integral part of the delivery of electricity in many countries throughout the world. This is because there are a number of advantages over AC transmission system in certain cases. The objectives of this literature survey are to study the application of HVDC and the reasons of using HVDC in transmission system. Some basic theories related to HVDC are also examined and analyzed in this survey. A case study on the Sabah/Sarawak-Peninsular Malaysia interconnection HVDC transmission system is discussed. This case study on the project is chosen because this transmission system will be the longest transmission system on the world and will benefit to Malaysia. This transmission system will launch in Malaysia soon. The analysis and discussion on the case study are done based on the theories studied.
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    A 11-year review of emergency obstetric hysterectomy (eoh) in Hospital Universiti Sains Malaysia Kubang Kerian, Kelantan January 2007 – December 2017
    (2020)
    Hashim, Noor Adibah Hanum Che
    Introduction: Emergency obstetric hysterectomy (EOH) is one of the life saving procedure performed in cases of intractable hemorrhage due to uterine atony, rupture uterus and placental disorders and it is usually reserved for the situations where conservative measures fail to control the hemorrhage. It is sometimes associated with both maternal and perinatal morbidity and mortality. Objective: To evaluate the prevalence, indications, maternal and perinatal outcome associated with emergency obstetric hysterectomy in a tertiary care hospital. Methodology: A retrospective study conducted in the Department of Obstetric & Gynaecology in Hospital Universiti Sains Malaysia (HUSM) for 11 years from January 2007 until December 2017 involving a total of 43 women who underwent emergency obstetric hysterectomy. The records of all cases of emergency obstetric hysterectomy were analyzed included patient profile, obstetric history, details of present labour, indications for obstetric hysterectomy and the fetomaternal morbidity and mortality associated with emergency obstetric hysterectomy. Results: Among 79,777 deliveries, there were 43 cases of emergency obstetric hysterectomy, giving the prevalence of emergency obstetric hysterectomy was 0.29 per 1000 deliveries. Maternal demographic characteristics showed that mean age was 36 years old in caesarean hysterectomy group while mean age for postpartum hysterectomy group was 33 years old. The most common parity group encountered in emergency obstetric hysterectomy was para two to para five. Whether or not women underwent prior uterine surgery was investigated and 30 women (69.77%) had history of previous caesarean section. Of the 30 women with an obstetric history of caesarean delivery, 15 (50%) had more than two caesarean deliveries. Placenta accreta was the most common indication for emergency obstetric hysterectomy (30 women, 69.8%) followed by uterine atony (10 women, 23.3%), uterine rupture (2 women, 4.7%) and extended tear (1 woman, 2.3%). Futhermore, about 93.33% (28 out of 30 patients) with adherent placenta had history of caesarean section prior. No maternal mortality reported in this study. The most significant maternal complications postoperatively include coagulopathy (12 out of 43 women), where 27.91% required massive transfusion protocol, followed with re-laparotomy (4 women, 9.3%), and febrile illness (3 women, 6.98%). Most of the babies were born with good Apgar score. The perinatal complication include perinatal death, 2 out of 43 babies, 4.65% were fresh stillbirth were both cases were referred to our center for abruptio placenta. Conclusions: Caesarean section, especially repeat caesarean sections in women with placenta previa and uterine atony, significantly increased the risks of emergency obstetric hysterectomy. Emergency obstetric hysterectomy is safe with reduce complications compared to before with advancement of obstetric care and good clinical practice. Early decision to perform emergency obstetric hysterectomy is essential before the patient’s condition deteriorates
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    A 5-year review of recurrent pelvic organ prolapse following pelvic reconstructive surgeries in Hospital Sultanah Nur Zahirah.
    (2020)
    Recurrent pelvic organ prolapse after primary pelvic reconstructive surgery is common with recurrence rate 29-34%. The study was carried out to determine the local prevalence of recurrent pelvic organ prolapse (POP) and to determine the associated factors for its recurrence following primary pelvic reconstructive surgery (PRS). It was a retrospective observational study which was carried out at Hospital Sultanah Nur Zahirah, Kuala Terengganu involving all patient who underwent PRS between 1st January 2011 and 31st December 2015. Case notes were review and patients who had recurrent POP more or equal to grade 2 Baden-Walker System within two years of the operation were included. A total of 125 patients were involved. The prevalence of recurrent POP following primary PRS in studied population was 24.8%. The association between each related variable towards recurrent POP was examined. However, no variables were found to be significant at the end. The prevalence of recurrent pelvic organ prolapse in HSNZ was 24.8% within two years interval between primary operation and recurrence. There were no significant risk factors identified to be associated with the recurrence in the studied population. However, the age was the nearest factor that influence recurrence of POP.
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    A benchmark low voltage of microgrid network
    (2010-04-01)
    Zulkifli, Nurul Asiah
    A study about microgrid network has been conducted to explore new and environmental friendly renewable energy. A few relevant papers concerning the microgrid network as higher energy efficiency and by facilitating the integration of renewable sources that is potential in the future market have been collected and studied. New renewable and efficient energy resources offers an alternative solution which integrating a network that is microgrid network. Microgrid can be connected to the main power network or be operated autonomously, similar to power systems of physical islands. Microgrid network is usually connected to an electrical distribution network in an autonomous way and employs various distributed generation technologies such as micro-turbines, fuel-cell, photovoltaic arrays, wind turbines and others system together with energy storage devices such as battery, condenser and flywheel. In addition, the benchmark low voltage provides the guidelines in the design of low voltage microgrid network. Moreover, standardizing case study grids to provide benchmark networks suitable for microgrid design would further enhances their merit and utility. Microgrid may potentially offer various advantages to end-customers, utilities and society, such as; improved energy efficiency, minimized overall energy consumption, improved services quality and reliability and also cost efficiency electricity infrastructure replacement.
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    A Case Control Study To Determine The Association Of Blood Groups And Allergic Rhinitis
    (2022-08)
    Chai Hui Yi
    The primary objective is to discover the association between ABO/rhesus blood groups and allergic rhinitis. Also, this study aimed to find out the association of demographic factors (gender and races) of patients and ABO blood groups.
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    A Case Study Of The Factors Influencing Argumentative Writing Activities Via Whatsapp Among Low Proficiency Esl University Students
    (2023-06)
    Haeza Binti Haron
    This case study examines low-proficiency university students’ views of three learning factors that influence ESL argumentative writing skills. This case study focuses on three factors: mobile technology via WhatsApp, peer interaction and teacher’s role to examine the low proficiency students at the university level view these factors as important learning criteria that can develop and support their ESL argumentative writing in answering the research questions.