Performance of Modification of a Three Phase Dynamic Voltage Restorer (DVR) for Voltage Quality Improvement in Electrical Distribution System

There is growing concern over power quality of ac supply systems. Power quality can be defined as the ability of utilities to provide electric power without interruption. Various power quality problems can be categorized as voltage sags, swells, harmonics, transients and unbalance are considered are the most common power quality problems in electrical distribution systems (Elandy etl., 2006). These types of disturbances can cause fails in the equipments, raising the possibility of an energy interruption.Voltage swells can be defined as a short duration increase in rms of main source with an increase in voltage ranging from 1.1 p.u up to 1.8 p.u. of nominal voltage source. There are various solutions to these problem

Purchase Intention of Customers Toward Health Products in Melaka State

Abstract - Currently, the number of companies offering health products is increasing over the years. This varied range of options available for customers has driven the researchers to dig out what the factors are that influence the intentions of purchasing by customers. The importance of this research was to actually realize what are the factors that could impact the behavior of customers in deciding which product to be purchased or to be bought.  The objectives of this research are to investigate the impact or relationship of customer knowledge, product performance, and health concern towards the purchase intention of consumers toward health products. In addition, the research is classified as a descriptive study to collect data by using a quantitative method. The researcher had distributed survey questionnaires to 201 respondents through online distribution after manual questionnaires have been answered by 20 respondents during the pilot test.  Data gathered and analyzed by using SPSS software. The results obtained showed significant influences between customer experience, customer attitude, perceived values, perceived usefulness, and health background on purchase intention of consumers toward health products. However, perceived ease of use and health awareness failed to achieve a significant correlation with the intention of purchase by consumers. Based on the discussions made on findings, this research may be able to be explored deeper view through further research in the future and eventually contributing to the industry.Keywords - Health products, customer attitude, customer experiences, perceived values, perceived usefulness, health background, purchase intention towards health product

Internet-of-Things (IoT) for Human Thermal Comfort: A Simulative Investigation

Human thermal comfort is very important especially in an indoor environment as it can influence human’s health and welfare. In tropical countries like Malaysia, air conditioning system has become a necessary tool in creating a thermally comfortable ambience in an indoor environment. However, the current control mechanism of the system would allow the user to set into maximum cooling – at minimum temperature with maximum fan speed – which not only consumes more energy, but is not creating a thermally comfortable environment as well, as extreme coolness could also bring negative effect towards the human. Therefore, it is essential to integrate human thermal comfort factor into air conditioning system control as well. This paper will highlight the possibility of integrating thermal comfort control into air conditioning system in creating a comfortable indoor environment. It adopts an enhanced version of Predictive Mean Vote (PMV) approach, specifically in creating thermal comfort ambience for a small sedentary work-based indoor space, in tropical countries. As the Internet-of-Things has become a trend in the smart home application, its element is also integrated here, where an Android-based application is developed and tested towards controlling a hardware simulative model which represents an air conditioning system based on the user-defined PMV value. It is shown that the application is able to control the fan speed and temperature through the LED brightness as demanded by the user. It is not only expected to work with a real air conditioning system in the future to create a thermally comfortable environment, but could also allow the system to be operated in energy and cost-efficient manner

Simulation of grid connected THIPWM-three-phase inverter using SIMULINK

This paper presents a grid connected system. Three phase DC-AC inverters used to convert the regulated DC power to AC power suitable for grid connection. Third harmonic injection PWM (THIPWM) was employed to reduce the total harmonic distortion (THD) and for maximum use of the voltage source. the accurate generation of THIPWM minimize the THD and make the inverter suitable for grid connection, by synchronizing the inverter voltage with the grid voltage. The application of THIPWM to inverter increases efficiency of the inverter. Simulation results validate the developed model and the proposed system

Blowfly Larval Tissues as a Secondary Detector for Determining Paraquat-Related Death in Rabbit Carcass

Paraquat poisoning is commonly associated with suicide or homicide in Malaysia. In a case involving advanced body decomposition, pathological analysis regarding the cause of death may become difficult or almost impossible. Insects serve as common alternative matrix for poison detection in forensic analysis. Paraquat detection via secondary bioaccumulation in fly larvae tissue has never been reported. In this study, tissues from blowfly larvae collected from a rabbit carcass with paraquat poisoning were analyzed for secondary bioaccumulation. Larvae samples were collected and analyzed using liquid-liquid extraction. The detection was performed via reduction of quaternary ammonium presence in paraquat and analyzed using gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring mode (SIM mode). GC-MS showed the elution of reduced paraquat was at retention time 12.8min. Blowfly larvae tissue has proven useful as a secondary detector in paraquat-related deaths

A comprehensive review of synchronization methods for grid-connected converters of renewable energy source

Recent interest in the integration of renewable energy sources (RES) into the power grid has raised concerns in synchronization of the various RES. Grid variables such as voltage, phase angle and frequency should be continuously monitored to guarantee correct operation and synchronization of power converters connected to the power grid. Numerous synchronization methods have been presented over the years to address issues such as unbalanced condition and frequency variation. This paper presents a review of past studies on synchronization methods for grid-connected converters together with their control and modeling techniques. Various estimation techniques for phase angle, frequency and harmonic are discussed and examined. Key challenges for a smart and efficient synchronization are briefly overviewed and possible future works are also recommended. A consolidated review is the particular focus of this paper, as is the provision of information on the best method for synchronizing grid-connected converters

A numerical model for the simulation of double-diffusive natural convection in a right-angled triangular solar collector

A numerical model is presented for the simulation of double-diffusive natural convection in a triangular solar collector. This design is encountered in greenhouse solar stills where vertical temperature and concentration gradients between the saline water and transparent cover induce flows in a confined space. This phenomenon plays an important function in the water distillation process and in the biological comfort. In this double-diffusion problem, the ratio Br of the relative magnitude thermal and compositional buoyancy and Rayleigh numbers are key parameters. Finite element technique is used to solve the governing equations. Numerical results are presented for the effect of the abovementioned parameters on local heat and mass transfer rate. In addition, results for the average heat and mass transfer rate are offered and discussed for the mentioned parametric conditions. Some interesting results are found in this investigation

Detection of Colletotrichum Gloeosporioides Fungus Isolates Development/Spread for Mango (Mangifera Indica L.) Cultivar from Electronic Nose Using Multivariate-Statistical Analysis

Agriculture plays a very important role in Asia economic sectors. For Malaysia, it plays a big contribution towards the country’s development. Mangifera Indica L., commonly known as Mango, is one of the fruit that has high economic demand and potential in Malaysia export business. However, due to radical climate changes from hot to humid, Mango is exposed towards a number of disease and this will affect its production. Colletotrichum gloeosporioides is one of the major diseases that could occur on any types of Mango. This fungus can attack on fruit skin and leaf, therefore a method that able to detect and control it would be much appreciated. Hence, this paper shows that the presence of Colletotrichum gloeosporioides type of pathogen can be detected by using Electronic Nose (E-Nose). The E-Nose will detect the Volatile Organic Compound (VOC) that produced from this fungus. Further analysis and justification on its existence are completed by using one of Multivariate-Statistical Analysis method which is Principal Component Analysis (PCA).The analysis results effectively show that the PCA is able to classify the number of isolating days of this type of fungus after cultured. Furthermore the potential of pre-symptomatic detection of the plant diseases was demonstrated

The Effect of Different Binder Compositions in Fabricating Silica Foam (SiO2) Via Replication Method / N.A.Nazaruddin...[et al.]

Ceramic foams or reticulated porous ceramic are form highly porous ceramic with closed, fully open and partially interconnected structure of porosity and wide range of application of the catalyst, electrical conductivity, refractory insulation of furnaces, filtration, adsorption and separation. There are various conventional method in fabrication silica foam such as direct forming, steam heating, freeze casting method and polymeric sponge method which is also well-known also as replication method. In this study, silica foam was fabricated using a 55wt. % of silica powder with different binder compositions of polyethylene glycol (PEG) and carboxymethyl cellulose (CMC) via replication method. The present work focuses in the effect of three variable compositions of PEG and CMC at high sintering temperature of 1250ºC in producing silica foams. The polyurethane foam (PU) acts as the template for slurry from silica powder compounds and mixed together with binders and distilled water. All samples are immersed into the SiO2 slurry and dried at a temperature of 100ºC for 24 hours. The green bodies of foams were further sintered at temperature of 1250ºC. The morphological analyses depicted that the size of the silica foam pores were in the range of 259.15μm to 559.83μm. It was found that the density of silica foam in the range of 0.4953 g/cm3 to 0.7170 g/ cm3. Whereas, the result of porosity percentage obtained from 61.38 % to 71.9 %. Density and porosity analysis shows that the density of foams increased with decreased porosity of the silica foam. Mechanical properties analysis with compressive strength give a result in a range of 0.1310 N/mm2 to 0.2329 N/mm2 respectively. Thus, the replication method adopted for the SiO2 foam fabrication was proven a success