Investigation on AC breakdown of vegetable oils with insulated electrodes

Most of power transformer design today is still using oil filled type which laminated iron core with paper insulated copper conductors. Oil is an important part in power transformers as electrical insulation, information carrier and cooling medium. Besides oil, paper insulation also plays important role as dielectric material of transformer. The influence of oil especially vegetable-based oil and paper insulation on the dielectric strength of transformer oil has attracted many researchers to do investigation. This paper presents a study of the quasi-uniform field AC breakdown voltages under bare electrodes, paper insulation for barrier and covered electrodes (to replicate the transformer windings) of Palm Oil (PO), Coconut Oil (CO) and Mineral Oil (MO). The data obtained from all tests were analyzed using Gaussian and Weibull distribution to determine the withstand voltages for each type of oils. The experiments were using test cell as specified by IEC 156 with 2.5 mm gap distance under uniform field

Syngas production from glycerol dry reforming using Nd2RuO5 perovskite catalysts

Currently, fossil fuels as the global energy sources have become a liability due to the emission of greenhouse gases that causes global temperature elevated and climate changes to happen more frequently. As a result, glycerol dry reforming (GDR) has been a research priority, owing to its reforming capabilities in turning greenhouse gases (CO2) and biodiesel byproducts (glycerol) into syngas. The choice of catalysts is critical for increasing the efficiency of the syngas production process. Hence, this paper studies the application of Nd2RuO5 perovskite catalysts on the dry reforming of glycerol. Before characterization, the catalysts were prepared by using the Pechini Sol-Gel method. GDR reactions were conducted using a fixed-bed reactor at operating conditions; 873 – 1173 K and CO2 to Glycerol ratio (CGR) at 1:1. Based on XRD finding, the dominant phase belongs to Nd2RuO5, a pseudo double perovskite. The reduction profile from TPR showed a lowered reduction temperature which belongs to Ru that reduced into Ru0. The images of perovskite showed a well dispersed and smooth surface, and no agglomeration occurred on the pore sites. From the catalytic evaluation on the effect of temperature, the best temperature was observed at 1073 K, giving the highest glycerol conversion at 69%, whereas for H2, CO yields 20.8% and 13.8%, respectively. Intense carbon formation has been detected at post XRD analysis which later confirmed to be a filamentous type, that oxidized at low oxidation temperature from 400 – 500 K

FEKF Estimation for Mobile Robot Localization and Mapping Considering Noise Divergence

This paper proposed an approach of Fuzzy-Extended Kalman Filter(FEKF) for mobile robot localization and mapping under unknown noise characteristics. The technique apply the information extracted from EKF measurement innovation to derive the best estimation output for a mobile robot during its observations. These information is then fuzzified using Fuzzy Logic technique with very few design rules to control the information which at the end further reducing the error about the measurement and consequently provide better localization and mapping. Simulation results are also presented to describe the efficiency of the proposed method in comparison with the normal EKF estimation that emphasize FEKF exceeds the estimation results of normal EKF in non-Gaussian noise environment

FEKF ESTIMATION FOR MOBILE ROBOT LOCALIZATION AND MAPPING CONSIDERING NOISE DIVERGENCE

ABSTRACT This paper proposed an approach of Fuzzy-Extended Kalman Filter (FEKF) for mobile robot localization and mapping considering unknown noise characteristics. The techniques apply the information extracted from EKF measurement innovation to derive the best output for mobile robot estimation during its observations. This information is then fuzzified using Fuzzy Logic technique, designed with very few design rules to control the information. The method can further reduced measurement error and as a result provides better localization and mapping. Simulation results are also presented to describe the efficiency of the proposed method in comparison with the normal EKF estimation. Preliminary results emphasize that FEKF has exceeds the estimation results performance of normal EKF in non-Gaussian noise environment

Robotics in school: a stem approach for creativity and innovation

Nowadays, knowledge in the field of Science, Technology, Engineering and Mathematics (STEM) is becoming very important. In order to attract students’ interest in this field, robotics lesson by using LEGO MINDSTORM EV3 is introduced to schools around Pekan, Pahang in collaboration with Pejabat Pendidikan Pekan, Pahang. This lesson is not only focussing on learning, it also shows how to design and assemble a machine or a robot. Besides the project is able to motivate students to think creatively and innovatively when doing activities. A lot of programmes and activities have been organised such as workshop, class and exhibition to deliver the lesson. This entire programme helps students and teachers to assess their skills and knowledge in science and mathematics. These programs have indirectly increases the interest among students and teachers as well as improving their academic performances. Our preliminary analysis shows that a number of students participated in this program have gained good academic results especially in Science and Mathematics. Undeniably, this program is able to support Science, Technology, Engineering and Mathematics (STEM) program especially for students and teachers in Pekan, Pahang

Analyzing the Mobile Robot Localization Performance in Partially Observable Conditions

This paper deals with theoretical investigation of robot localization considering partial observability conditions. The problem is very important as most of the mobile robot applications are controllable but not observable due to some aspects. The paper investigate the importance of correlation to the mobile robot estimation through the technique of decorrelating some of the elements of state covariance of the updated state covariance. To demonstrate the effect of correlation, two cases of partial observability are examined which are the unstable and stable partial observability. The cases are build based on the configurations of the state covariance for mobile robot references when doing observations. Our preliminary results suggest that the system with stable partial observability shows very good and consistent estimation while the unstable case lead to inconsistency and erroneous estimation

A study on data-driven impedance matching in four channels bilateral teleoperation

A teleoperator system comprised of dual robots namely the master robot controlled by the human operators, and remote slave robots which tracks the motion of master, where it concurrently transmits the environment’s force back to the human operator. Problems arose when there exists a mismatch in terms of system dynamics between master and slave manipulators, which consequently yields to a distorted transparency between both sides of the systems. Therefore, there is a need to overcome the said mismatch pattern in the overall closed-loop architecture. The main objective of this research is to design and develop control algorithms to drive both sides of the master and slave system to attain symmetrical impedance between them. By ensuring that both sides are symmetry, a good transparency is feasible. The proposed techniques was to introduce an equalizer or controller connected to the master manipulator. Then, by utilizing the model-free approach, namely the Fictitious-Reference-Iterative-Tuning (FRIT), the controller can then be properly tuned to obtain a good control performance. This project focused on the computational modeling where the proposed impedance matching algorithms have been investigated and analyzed utilizing the Matlab (Simulink) Software. There are several possible applications that can employ the control algorithms derived from this project. Obviously, underwater tele-robotics may find the proposed technique is beneficial since the model-free approach which dealt mainly on the measured input-output data in tuning procedure, can help to overcome the uncertainty that exists in the underwater environment. Besides, we also had investigated and analyzed the feasibility of this technique when working with multi-slave manipulators configuration. Hence, this open the opportunity for applications that utilize the multi-robots configurations such as in automotive or manufacturing industries. In general, it was found that a symmetric impedance between the master and slave manipulators attainable with the utilization of equalizer in the form of Laguerre network connected in feedback-loop to the master manipulator. This was also applicable for the case of single-master-multiple-slaves system, but additional passive decomposition algorithm must also be employed to treat the multi-slaves manipulators into the Locked and Shape subsystems

Influence of g-C3N4 and PANI onto WO3 photocatalyst on the photocatalytic degradation of POME

Presently, the blossoming interest for efficient photocatalytic degradation has come to fruition, which is a promising candidate towards clean energy and a sustainable environment. Introducing doping factor is a great strategy to promote photocatalytic performance of catalysts. For a more effective boost of Aeration-POME (Ae-POME) degradation and efficient photocatalytic visible light absorption, the tungsten trioxide (WO3) was wrapped on graphite carbon nitride (g-C3N4), and the polyaniline (PANI) were prepared using a facile method. The binary photocatalysts was characterized by zeta potential and Fourier-transform infrared spectroscopy (FTIR). As anticipated, WO3/g-C3N4 and WO3/PANI showed excellent catalytic and photocatalytic performance of the color and COD removal of Ae-POME. The WO3/g-C3N4 composite removed color and COD at approximately 30% and 37% of POME, respectively, as compared to WO3/PANI in the absence of light, where less than 30% of color were removed under visible light irradiation and energy storage scheme. In addition, the FTIR studies support the discussions on the effect of doping on POME photocatalytic activity. The significantly enhanced photocatalytic performance is attributed to the synergetic effect of g-C3N4 and PANI, which can create the internal driving force to improve the separation efficiency of charge carriers in WO3. This doping method and the energy storage principle will provide a valuable strategy for the development of a feasible photocatalyst with specific unique structures

Effects of operating parameters on cadmium removal for wastewater treatment using zeolitic imidazolate framework-L/graphene oxide composite

Water pollution due to heavy metal contamination has become a critical environmental issue. Thus, effective treatment for polluted water, such as simple adsorption to remove heavy metals, is gaining importance. Towards this end, zeolitic imidazolate framework-L (ZIF-L) with graphene oxide (GO) was successfully incorporated in the synthesis of novel ZIF-L/GO 20 and ZIF-L/GO 50 adsorbents using 20% and 50% loading percentages of GO, respectively, with ultrapure water as the solvent. The morphologies of ZIF-L changed to a flower-like structure with the introduction of 20% GO and turned into smaller irregular shapes when 50% GO was added. These novel adsorbents have demonstrated high adsorption capacities for Cd(II) adsorption at 172.42 mg/g (ZIF-L/GO 20) and 188.68 mg/g (ZIF-L/GO 50), with the optimum dosage of 0.2 g/L of adsorbents. The adsorption isotherms fit Langmuir isotherm, which suggested that adsorption occurred through uniform and monolayer sorption on the surface sites. The electrostatic attraction between the cationic Cd(II) and negatively charged surface played a crucial role as the main pathway in Cd(II) adsorption. Based on the investigated kinetic models, Cd(II) adsorption had a better correlation with the pseudo-second-order kinetic model, which showed that chemisorption occurred during the Cd(II) removal process. The findings of this study revealed that ZIF-L/GO has the potential of becoming the perfect adsorbent for cadmium removal from aqueous solutions

Zeolitic imidazolate framework-L incorporated graphene oxide hybrid for cadmium removal

The removal of cadmium from wastewater is crucial to avoid its harmful effects on the ecosystem. Thus, in this study, novel composites were prepared by in situ synthesis of zeolitic imidazolate framework-L (ZIF-L) incorporated with graphene oxide (GO) of different loading ratios to produce ZIF-L/GO 20 and ZIF-L/GO 50. The adsorbents were characterized using X-ray Diffractometer (XRD), Fourier-transform Infrared Spectroscopy (FT-IR), and Scanning Electron Microscopy (SEM). The effects of Cd(II) adsorption with respect to the initial pH solution, adsorbent dosage, initial Cd(II) concentration, and contact time were investigated. Both ZIF-L/GO 20 and ZIF-L/GO 50 showed superior performance in removing Cd(II) as compared with ZIF-L (62.32% within 160 min), which were 64.35% and 70.41% within 60 min and 180 min, respectively. The optimum dosage obtained was 0.2 g/L for the removal of 100 mg/L Cd(II) synthetic wastewater. The protruding grains of flower-like ZIF-L/GO 20 allowed for faster adsorption time, whereas the smaller size of irregular shapes ZIF-L/GO 50 increased the surface area for higher adsorption capacity. Also, the adsorption of Cd(II) had fitted well with pseudo-second-order kinetic model and Langmuir isotherm. The Langmuir maximum adsorption capacities for ZIF-L, ZIF-L/GO 20, and ZIF-L/GO 50 were 163.93, 172.42, and 188.68 mg/g, respectively. The novel adsorbents ZIF-L/GO 20 and ZIF-L/GO 50 showed promising performance in the removal of Cd(II) ion from the aqueous solution