Journal of Applied Materials and Technology
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A Deep-Learning Approach to Load Modeling in Modern Power Distribution System
Get PDFModern Power Distribution Networks (MPDNs) are no longer passive because Distributed Generations (DGs) are integrated with them to enhance system reliability and power quality. For this reason, load modeling has to be updated to capture the new dynamics of active DNs. This paper presents a composite load modeling for a grid-connected photovoltaic (PV) distribution network using the Levenberg-Marquardt algorithm in the deep learning feed-forward neural network approach. Load modeling is constructing a relationship between input excitation(s) and output response(s); it can be used for simulation studies, stability analysis, and control/protection design. A grid-connected PV distribution network was modeled in Matlab/Simulink and generates data for training and model estimation. The estimated model was tested and validated using a laboratory experimental test bed. Results of the model exhibit a good fitness of 99.8% and 97.2% in active and reactive power models respectively during training. While 97.84% and 94.65% respectively were obtained during testing. The estimation errors were found to be 0.0025 and 0.0049 for active and reactive powers respectively with 0.0473 and 0.0701 corresponding errors in testing
Simulations of the Crude Oil Tank Refurbishment Project Risks Using Monte Carlo
Get PDFSimulation technology has assisted project stakeholders in predicting a range of the project results in the future under risks and uncertainties. The objectives of this article are to improve a comprehensive project planning in the perspective of the project scheduling by conducting simulations for the refurbishment of crude oil tank project risks using Monte Carlo simulations. The practical approaches for simulating the risks encompassed 3 stages: risk identification, assessment, and risk analysis using the Monte Carlo simulations. The implementation of Monte Carlo simulation in the form of stochastic approach however were not new, but the application of these approaches in the area of oil industrial projects was challenging. A Free Water Knock-Out (FWKO) tank project located in Duri, Indonesia was taken as a case study. The initial FWKO project duration was set up to be 180 working days, and it was delayed (up to 140% from the initial duration of the project planning). This study conducted deep questioner surveys from 25 oil industry stakeholders. It was identified 29 risk factors have been considered as the major causes of the project delay. The risk factors were then calculated qualitatively for performing risk indexes. Based on the risk simulations (after 1000 iterations) using Monte Carlo simulations utilizing @risk application package (under uncertainties) there was found that the possibility of this project would experience delays at the range of 47 days (126%) to 80 days (144%) from the initial project planning. This simulation had also identified the most sensitive activities causing project delays. The results was presented in the form of the spider graph diagram which assisted the project main stakeholders in developing a strategic decision during project planning phase
3D Finite Element Model for Shear-dominant Failure of Reinforced Concrete Beams
Get PDFThis study explores the 3D FE modelling approach in determining the behaviour of shear-dominant responses of RC beams. Five RC beams (A1, A2, B1, C2 and C3) with different cross-sections, amount of tension reinforcement area, amount of shear reinforcement and the length of the span was analysed and the results were compared with the results of the experiment and 2D analysis available in published literature. RC beams analysed in this FE study were constructed as a discrete model using ABAQUS software. The concrete and the plate for loading as well as for supports were modelled using the C3D8R element while longitudinal steel bars and stirrups were modelled with the T3D2 element. The interaction between the steel bar and the concrete in the FE model was assumed perfectly bond. The material behaviour of concrete was modelled with the damage plasticity model where the yield or failure of the material was governed by the tensile cracking and the compressive crushing of the concrete by introducing the hardening variables. The results showed that crack propagation in the FE analysis matched the cracks observed in the test. The crack pattern on Beam A1, A2, B1 and C2 indicated that the specimens experienced flexure and shear failure while Beam C3 experienced less brittle behaviour. Estimates of strength and the load–deformation response of 3D analysis were certainly achieved with reasonable accuracy compared to that of 2D analysis. The difference of experiment-to-2D strength (Pu,exp - Pu,2D / Pu,exp) had a mean of 4.53 whereas the difference of experiment-to-3D strength (Pu,exp - Pu,3D / Pu,exp) had a mean of 1.83. Furthermore, the displacements at ultimate load gained in the 3D analysis were comparable to those of experiments. The difference of experiment-to-2D (du,exp - du,2D / du,exp) and experiment-to-3D (du,exp - du,3D / du,exp) midspan displacement had a mean of 19.91 and 10.89, respectively
Determination of soluble hexavalent chromium in samples of Portland cement from Brazilian cement manufacturers
Get PDFUrbanization growing is nowadays highlighted in the big cities. Therefore, it is necessary to increase the production of cement, which is used in several areas of civil construction, to supplement the growing demand. Thus, the objective of this study was to determine the content of hexavalent soluble chromium in Portland cement samples from different cement industries in São Paulo state, Brazil, since this chemical species can cause adverse health effects as well as being a potential human carcinogenic for those who manipulate it. In Brazil, the emission of Cr6+ in the cement has no restrictions, since there is no current Brazilian law that determines the maximum concentration of it, whereas, in Europe, the current law 2003/53/EC establishes a maximum of 2 mg.kg-1. So, the Cr6+ content for different cement samples was determined by spectrophotometry based on the European standard EN196-10/2006. It was found by the analysis that among all types of cement produced in São Paulo, the only one that did not exceed the standard limit was the CP III, probably because this kind of cement has a high concentration of additions in its composition, responsible for diluting thereby chromium content. The other types of cement exceeded the established limit. It was concluded that Brazil urgently needs a law to regulate the hexavalent soluble chromium emission present in Portland cement to minimize the environmental and health effects that the cement out of specification may cause
A Review on Optimal Siting and Sizing of DSTATCOM
Get PDFThe continuous demand for electrical energy by industries and domestic users have stressed the electricity consumption to a high level. Because most components of domestic and industrial systems are made of power electronics devices in their designs. In addition, modern electrical power distribution networks (DNs) are subjected to major disturbances. Consequently, today’s power system is laden with power quality problems such as excessive energy losses, voltage deviations, poor power factor (PF), voltage instability and reliability issues to mentioned just a few. To forestall these disturbances, Distribution Engineers have introduced the use of Custom Power Devices (CPDs) in order to reduce power losses so as improve power quality. Amongst CPDs, Distribution Static Compensator (D-STATCOM) proves most promising in minimizing power quality issues because it generates minimal harmonics, waste less power, has small size, high regulatory capability and cost effective. Researchers in recent years have focused on methodologies required for identifying the most suitable location and rating of D- STATCOM device based on divergent views. However, to date, only one author has so far reviewed a paper on this aspect of study. This paper discusses the latest study on appropriate installation and rating of D-STATCOM techniques for balanced and unbalanced radial distribution networks (UBRDNs). The paper has also provided a comprehensive literature study on the location of DSTATCOM in RDNs for power loss reduction and power quality enhancement. Comparative analyses of various techniques for development of DSTATCOM Objective functions and constraints; Merits and Demerits are presented
Aluminium Tertiary Industry Waste and Ashes Samples for Development of Zeolitic Material Synthesis
Get PDFWastes generated in large amounts have been recognized as sustainable sources of raw materials for the synthesis of adsorbents. The synthesis of zeolite through wastes recycling of two different ash sources (coal bottom ash and sugarcane waste ash) and industrial aluminum waste was evaluated. The molar ratio of SiO2/Al2O3 for zeolite 4A formation was achieved by the addition of aluminum waste from tertiary industry as aluminum source. Coal bottom ash and sugarcane waste ash were used as a source of both silica and alumina. The synthesized materials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and cation exchange capacity (CEC). The analysis of the properties of the products demonstrates that the by-products can be used to produce zeolite A. The utilization of synthesized zeolites as adsorbent for cadmium removal from aqueous solution was conducted following the concept of implementation of utilization of waste materials as a component of the circular economy in the wastewater sector
Electroencephalogram (EEG) Based Imagined Speech Decoding and Recognition
Get PDFThe recent investigations and advances in imagined speech decoding and recognition has tremendously improved the decoding of speech directly from brain activity with the help of several neuroimaging techniques that assist us in exploring the neurological processes of imagined speech. This development leads to assist people with disabilities to benefit from neuroprosthetic devices that improve the life of those suffering from neurological disorders. This paper presents the summary of recent progress in decoding imagined speech using Electroenceplography (EEG) signal, as this neuroimaging method enable us to monitor brain activity with high temporal resolution, it is very portable, low cost, and safer as compared to other methods. Therefore, it is a good candidate in investigating an imagined speech decoding from the human cortex which remains a challenging task. The paper also reviews some recent techniques, challenges, future recommendations and possible solutions to improve prosthetic devices and the development of brain computer interface system (BCI)
Lifting removal of cationic dye (methylene blue) from wastewater by improving Zr-MOFs via second metal Al coordination
Get PDFMetal organic frameworks (MOFs) are frequently used as adsorbents in adsorption processes to remove dyes from effluent produced by the textile industry. Today, dye contaminants have become an important environmental problem. One of these dyes is methylene blue (MB) and its removal from wastewater is a priority because it is persistent and nondegradable. MB is used in many industries although it has potential harmful effects on human and aquatic life and can be considered a hazardous chemical when in wastewater. The present study shows the potential applications for enhanced forms of UiO-66 MOFs, such as UiO-66, UiO-66-10%Al and UiO-66-30%Al. These forms were prepared to remove MB from wastewater using batch experiments. Characterisation of adsorbents were accomplished successfully using Fourier transform infrared, X-ray powder diffraction, Brunauer–Emmett–Teller surface area and thermogravimetric analysis techniques. To investigate equilibrium adsorptive behaviour, Langmuir and Freundlich isotherm models were tested against the experimental data. Based on linear regression correlation coefficient (R2), the Freundlich model described the equilibrium isotherm of MOF/MB better than the Langmuir model. Of all forms of UiO-66 MOF, UiO-66-10%Al had the maximum Langmuir adsorption capacity at 49.26 mg/g. A kinetics study examined pseudo first-order, pseudo second order and Elovich models to determine which could explain the sorption mechanism. While the pseudo second order and Elovich models showed a good fit with the experimental data, the correlation coefficient of the pseudo second-order model was the highest. These results indicate that adsorption of MB is controlled by a chemisorption mechanism. Further, intraparticle diffusion was utilised to describe the adsorption mechanism and determine the rate-limiting steps in the adsorption process
Front Matter
No full textStatements of fact and opinion in the articles in the Journal of Applied Materials and Technology are those of the respective authors and contributors and not of Journal of Applied Materials and Technology or the institution of Applied Materials and Technology Society and Faculty of Engineering, Universitas Riau. Neither Applied Materials and Technology Society and Faculty of Engineering, Universitas Riau nor Journal of Applied Materials and Technology make any representation, express or implied, in respect of the accuracy of the material in this journal and cannot accept any legal responsibility or liability for any errors or omissions that may be made by the reader should make her or his own evaluation as to the appropriateness or otherwise of any experimental technique described