Universiti Teknikal Malaysia Melaka: UTeM Open Journal System
Not a member yet
2735 research outputs found
Sort by
Review of Radiation Pattern Control Characteristics for The Microstrip Antenna Based On Electromagnetic Band Gap (EBG)
Get PDFRadiation Pattern of the antennas is necessary for many applications in the telecommunication field, such as wireless communications and radar. They lessen the interference by channelling the radiation of antenna to the interested direction to achieve the enhancement of spectrum efficiency and multipath propagation reduction that results in the saving of radiation power and the increase in gain. Various techniques have been used to implement beam steering for several years. Electromagnetic band gap (EBG) with unique features helps to prevent/assist the electromagnetic waves propagates in a specific band of frequency for all polarisation states and all incident angles. In this paper, the advantages of the EBG surface wave band gap feature were identified, if it is inserted with microstrip antennas design, which helps to rise the gain of antenna, reduce the back lobe and lessen the mutual coupling in array components. Additionally, more advantages due to the surface waves suppression and the stopping band and passing band of the EBG have been achieved in the beam steering by integrating the single patch microstrip antenna with EBG. Additionally, the new antenna structure based on the combination of the concept of a reconfigurable planar array antenna with the EBG elements requires further research to produce a new radiation pattern control technique
ENHANCING GRAPHITIC CARBON CONTENT OF CARBON-BASED ELECTRODE MATERIALS BY PULSED ELECTROPHORETIC DEPOSITION FOR ELECTROCHEMICAL CAPACITOR
Get PDFCrystallinity of carbon electrode materials and their deposition techniques are the crucial factors for electrochemical capacitor (EC) performance. The present work investigates deposit yield and graphitic content of activated carbon (AC) and CNT coatings deposited by pulsed electrophoretic deposition (EPD). Pulse voltage with pulse separation times of 30 to 50 s, alternated with the long pulse width (i.e. 2.5 min) was applied. Although the pulse separation time at 30 s reduced the CNT coating yield, its graphitic content increased by 40 % as compared to the CNT coating deposited by continuous voltage EPD, as indicated by the IG/ID ratio of Raman spectra. However, graphitic content increase was not observed in the deposition of AC. Consequently, the CNT deposition gained a higher graphitic-nongraphitic content ratio than the AC. This finding opened up the possibility of the EC performance enhancement by the graphitic CNT control in electrode materials through EPD process
A Framework for Improving Manufacturing Overall Equipment Effectiveness
Get PDFThe main motivation for improving productivity is to develop and implement manufacturing methods and concepts that provide stable, flexible and low cost production with high quality levels. However in the pursuit of increasing competitiveness may lead to plant downtime; which must be minimized wherever possible. Overall equipment effectiveness (OEE) is a metric to measure equipment performance and effectiveness and therefore, reduce equipment cost of ownership (COO). OEE topic has become progressively popular and widely used as a research discussion in operation management. However, OEE framework for previous studies was developed on a piecemeal basis. This paper presents a new and complete conceptual framework that illustrates the most important factors that influence and contribute to OEE improvement. The comprehensive framework is able to provide effective guidance and direction to industry practitioner on how to improve OEE
HYBRIDIZATION AND THERMAL STABILITY EFFECTS ON PHYSICAL PROPERTIES OF HYBRID GLASS/JUTE FIBER REINFORCED EPOXY COMPOSITES
No full textIncorporation of natural fibers with partial replacement of synthetic fibers leads to a new venture in composite tooling industries due to their recyclability limitation as well as potential for weight and cost reduction. This work compares the density and evaluates the effect of thermal cycles of 0, 1, 3, 7, 12, 20, 30 and 50 cycles at two different temperatures; i) 120°C and ii) 200°C to the physical properties of hybrid glass/jute fiber reinforced epoxy laminated composites. The composites were prepared via vacuum infusion working at a pressure of 100 kPa, soaking time of 120 minutes and with the use of flow media. The composite exposed to thermal cycles at 200°C exhibited lower density due to removal of volatile elements which lead to porous structures. It experienced higher weight loss from partial degradation of natural fibers at 200°C. The composite subjected to thermal cycle at 120°C showed stable physical properties even after 50 thermal cycles. The water absorption reflects the level of curing completeness, which varies with exposed temperature and number of thermal cycles. The findings indicate that the hybrid glass/jute fiber reinforced epoxy composite exhibits potential to be used as a tooling material with apparent weight reduction and dimensional stability under thermal effect
Study of Morphological, Optical and Electrical Properties of Graphene Oxide Thin Film Relative to the Reaction Time of Synthesis
No full textIn this work, graphene oxide (GO) was synthesized by treating graphite powder with potassium permanganate (KMnO4) and a mixture of concentrated sulphuric acid (H2SO4)/ phosphoric acid (H3PO4) at various reaction time. The GO thin film is coated on a glass substrate by using drop casting method. The morphological, optical and electrical properties of GO thin film were carried out by using scanning electron microscopy (SEM), UV-Vis spectroscopy (UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR), and current-voltage (I-V) characteristic. The morphological study of GO shows that more oxygen functional groups were observed as the reaction time increases from 24h to 96h and is justified from the optical properties of GO thin films. The optical and morphological properties of GO thin film affects the electrical properties as the resistivity increase from 9.33 x 106Ω.cm to 26.15 x 106Ω.cm. Morphological and optical data confirms that 48h is the optimized reaction time having a resistivity of 12.30 x 106Ω.cm
Analysis of Nonlinear PID Controller for Tracking Performance of Ball Screw Drive
No full textIn control system industry, it is crucial to have good tracking performance at higher speed. However, cutting force disturbances in machining affect the performance. Therefore, a good controller is important to compensate the disturbances. The focus area in this paper is to evaluate the tracking performance of Nonlinear PID (NPID) controllers based on two conditions. The first condition is based on a bounded nonlinear gain, K(e) and secondly is based on constructing two parameters of integral controlled quantity, Ui and differential control efficient, Kd. The performance measures for this research are 10mm for every 0.4Hz and 0.7Hz of reference input to evaluate the tracking performance of the controllers. This research focuses on the comparison of two sets of the condition of NPID controllers for x-axis of ball screw drive. There are three analyses to classify the performances; maximum tracking error, root means square error (RMSE) and error reduction. The results show that NPID based on a bounded nonlinear gain K(e) has better tracking performance than NPID based on Ui and Kd. NPID controller (K(e) based) successfully reduced 33%-37% of error compared to NPID controller (Ui and Kd based). The designed controllers can have an adaptive algorithm to improve the adaptation of the controllers to the system as the recommended purposes
Design, Simulation and Fabrication of Dual-Band Polarized Microstrip Patch Antenna
No full textA new design of a simple dual-band and dualpolarised microstrip patch antenna is presented with a single feeding. Paper present two designs to make antenna compact without much alteration results. The proposed antennas are designed, simulated and fabricated and tested to be used in dual frequency bands which are GSM900 and 1800 bands. The Design I can be operated at frequency ranges from 924MHz to 1790MHz for simulation and real measurement from 938MHz to 1837MHz. Meanwhile, the operating frequency ranges for Design II from 900MHz to 1760MHz for simulation and real measurement between 904MHz to 1775MHz. The results show the simulated and measured result are in good agreement
Modeling of Energy Production of Sengguruh Hydropower Plant Using Neuro Fuzzy Network
No full textThe hydroelectric power plant needs to be operated carefully to obtain optimal results, as it is highly dependent on water availability. Factors to take into account are the water discharge and the duration of time for the operation. Decomposition analysis method is the method chosen to manage the operation of hydropower. This paper discusses the hydropower operation model using artificial intelligence with Neuro Fuzzy Takagi-Sugeno (NFTS) network technique. The Hydropower plants selected for modeling is Sengguruh Hydroelectric Power Plant with a capacity of 29 MW. This model was developed using three factors as inputs. They are the discharge of water, turbine water discharge and duration of operation time. The output is electric energy production. The data used is the operating data for one year, from January to December. The model testing shows satisfactory results as it reveals the real conditions and the errors occurred on the network was below 6.7%
Readiness of Information Security Management Systems (ISMS) Policy on Hospital Staff Using e-Patuh System
No full textISO 27001:2013 is the best-known standard providing requirements for information security management systems (ISMS). An ISMS is a systematic approach to manage sensitive information through people, processes and IT systems. In a hospital, a patient's individual medical record is highly private and sensitive. This study performed qualitative questionnaire based on the ISO27001:2013 policy. Seven hospitals in Malaysia were involved in this study. This study focus on the Data Center as it contains a high risk server. This study reveals the non-compliance issues among the sampled hospitals in Malaysia. The participation of the hospitals in trainings related to information security awareness and education were still not adequate due to lack of support from the top management. The Malaysian Administrative Modernisation and Management Planning Unit (MAMPU), the Ministry of Health Malaysia and the top management in hospitals in Malaysia play vital roles to educate and ensure the compliance of ISO 27001:2013
Classification of The NTEV Signal Problem via the Incorporation of S-Transform Features and Different Types of Neural Network
No full textClassification of power quality (PQ) disturbance on the commercial building is one of the most important parts in monitoring, identifying and mitigating of PQ disturbance to avoid misunderstanding the behavior of events. A novel on the Neutral to Earth Voltage (NTEV) classification using Stransform (ST) and different type of neural networks are proposed. The types of a neural network composed of general regression neural network (GRNN), probabilistic neural network (PNN) and radial basis function neural network (RBFNN). NTEV signals are needed to analyse using ST to extract their features that used as an input for the neural network classification. Finally, the GRNN, PNN, and RBFNN are trained and tested using 100 and 150 samples respectively. The performance of GRNN, PNN, and RBFNN are compared in which to identify the best technique in classification the NTEV