2,926 research outputs found
Preparation and characterisation of irradiated waste eggshells as oil adsorbent
Adsorption method had been developed by using natural organic adsorbent for the
removal of oil because of its ability to bind the oil molecules into the surface of adsorbent. In
this study, chicken eggshells waste was used and it undergoes irradiation process with four
different amount of dose which was 0.5 kGy, 1.0 kGy, 1.5 kGy, and 2.0 kGy by using Gamma
Cell Irradiator. Three equipment had been used for the characterization process which were the
Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX), and
Fourier-Transform Infrared Spectroscopy (FTIR). The adsorption experiment was conducted
to calculate the sorption efficiency by using different mass of samples. The result showed that
irradiated chicken eggshells powder with 2.0 kGy amount of radiation dose has a best
performance as oil adsorbent
Arcing High Impedance Fault Detection Using Real Coded Genetic Algorithm
Safety and reliability are two of the most important aspects of electric power supply systems. Sensitivity and robustness to detect and isolate faults can influence the safety and reliability of such systems. Overcurrent relays are generally used to protect the high voltage feeders in distribution systems. Downed conductors, tree branches touching conductors, and failing insulators often cause high-impedance faults in overhead distribution systems. The levels of currents of these faults are often much smaller than detection thresholds of traditional ground fault detection devices, thus reliable detection of these high impedance faults is a real challenge. With modern signal processing techniques, special hardware and software can be used to significantly improve the reliability of detection of certain types of faults. This paper presents a new method for detecting High Impedance Faults (HIF) in distribution systems using real coded genetic algorithm (RCGA) to analyse the harmonics and phase angles of the fault current signals. The method is used to discriminate HIFs by identifying specific events that happen when a HIF occurs
MRI brain classification using support vector machine
The field of medical imaging gains its importance with increase in the need of automated and efficient diagnosis in a short period of time. Other than that, medical image retrieval system is to provide a tool for radiologists to retrieve the images similar to query image in content. Magnetic resonance imaging (MRI) is an imaging technique that has played an important role in neuroscience research for studying brain images. Classification is an important part in retrieval system in order to distinguish between normal patients and those who have the possibility of having abnormalities or tumor. In this paper, we have obtained the feature related to MRI images using discrete wavelet transformation. An advanced kernel based techniques such as Support Vector Machine (SVM) for the classification of volume of MRI data as normal and abnormal will be deployed
Improvement of strength and water absorption of Interlocking Compressed Earth Bricks (ICEB) with addition of Ureolytic Bacteria (UB)
Interlocking Compressed Earth Brick (ICEB) are cement stabilized soil bricks that allow for dry stacked construction. This characteristic resulted to faster the process of building walls and requires less skilled labour as the bricks are laid dry and lock into place. However there is plenty room for improving the interlocking bricks by increase its durability. Many studies have been conducted in order to improve the durability of bricks by using environmentally method. One of the methods is by introducing bacteria into bricks. Bacteria in brick induced calcite precipitation (calcite crystals) to cover the voids continuously. Ureolytic Bacteria (UB) was used in this study as a partial replacement of limestone water with percentage of 1%, 3% and 5%. Enrichment process was done in soil condition to ensure the survivability of UB in ICEB environment. This paper evaluates the effect of UB in improving the strength and water absorption properties of ICEB and microstructure analysis. The results show that addition of 5% UB in ICEB indicated positive results in improving the ICEB properties by 15.25% in strength, 14.72% in initial water absorption and 14.68% reduction in water absorption. Precipitation of calcium carbonate (CaCo3) in form of calcite can be distinguish clearly in microstructure analysis
Generalization Bounds in the Predict-then-Optimize Framework
The predict-then-optimize framework is fundamental in many practical
settings: predict the unknown parameters of an optimization problem, and then
solve the problem using the predicted values of the parameters. A natural loss
function in this environment is to consider the cost of the decisions induced
by the predicted parameters, in contrast to the prediction error of the
parameters. This loss function was recently introduced in Elmachtoub and Grigas
(2017) and referred to as the Smart Predict-then-Optimize (SPO) loss. In this
work, we seek to provide bounds on how well the performance of a prediction
model fit on training data generalizes out-of-sample, in the context of the SPO
loss. Since the SPO loss is non-convex and non-Lipschitz, standard results for
deriving generalization bounds do not apply.
We first derive bounds based on the Natarajan dimension that, in the case of
a polyhedral feasible region, scale at most logarithmically in the number of
extreme points, but, in the case of a general convex feasible region, have
linear dependence on the decision dimension. By exploiting the structure of the
SPO loss function and a key property of the feasible region, which we denote as
the strength property, we can dramatically improve the dependence on the
decision and feature dimensions. Our approach and analysis rely on placing a
margin around problematic predictions that do not yield unique optimal
solutions, and then providing generalization bounds in the context of a
modified margin SPO loss function that is Lipschitz continuous. Finally, we
characterize the strength property and show that the modified SPO loss can be
computed efficiently for both strongly convex bodies and polytopes with an
explicit extreme point representation.Comment: Preliminary version in NeurIPS 201
Malaysia attempts in reduce carbon dioxide (CO2) emission and sequestration in bio-concrete system; a future direction
In Malaysia, upbringing the production of mussel is one of the most second important aquaculture The greenhouse gasses increase in this century especially carbon dioxide (CO2) compare to the previous centuries due to the increase of anthropogenic activities in all countries around the world [1][2][3]. The high concentration CO2 in the atmospheric cause a catastrophic environmental issues such as; global warming, change in rainfall, rise of sea level and climatic changes.
Development of Ultra-Wideband (UWB)Horn Antenna Using Approximation Method
This paper presents a design of an ultra wide-band
(UWB) horn antenna for microwave imaging radar system. The
key purpose of the study is to design a horn antenna which is used in medical imaging system. The proposed antenna operates within 3.1-10.6 GHz as it is the band allocated for medical industry usage. The antenna known as a directional antenna which is supported by rectangular waveguide. The horn antenna is purposely chosen to design in order to increase the directivity of the antenna within 15-20 dB and achieve higher gain and wider bandwidth as possible. This horn antenna is capable to produce return loss as minimum as possible. The antenna is designed and simulated using CST Microwave Studio. The simulation results show that the pyramidal horn antenna structure exhibits low VSWR as well as good radiation pattern over 3.1-10.6 GHz frequency ban
Assessment of the Reaction Time on the Morphology and Quality of Carbon Nanotubes – Silica Microparticles
AbstractCarbon nanotube has been grafted in-situ on the surface of spherical silica gel via floating-catalyst chemical vapour deposition method. The reaction temperature was set to be 760°C and 5wt. % of ferrocene catalyst (dissolved in toluene) injected into the furnace at a rate of 0.04ml/min. The reaction time was varied from 1 hour to 8hours, with one hour interval. It was found that the reaction time of 3hours yields the best quality hybrid particles. Prolonging the reaction time more than 3hours resulted in the formation of CNT that consists of thicker tubes, based on the observation via Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (TEM). Secondary overgrowth was observed via TEM for tubes synthesized at 7hours and 8hours. These results were in agreement with Raman Spectroscopy analysis where the IG/ID ratio were very small, indicating high defects and impurities in the samples synthesized at reaction time higher than 3hours
Antimicrobial activities of marine fungi from Malaysia
Copyright 2011 Elsevier B.V., All rights reserved.Peer reviewedPublisher PD
Ventricular arrhythmias classification and onset determination system
Accurately differentiating between ventricular fibrillation (VF) and ventricular tachycardia (VT) episodes is crucial in preventing potentially fatal missed interpretations that could lead to needless shock to the patients, resulting in damaging the heart. Apart from accurately classifying between VT and VF, the predetermination of the onset of the ventricular arrhythmias is also important in order to allow for more efficient monitoring of patients and can potentially save one’s life. Thus, this research intends to focus on developing a system called Classification and Onset Determination System (CODS) that is able to classify, track and monitor ventricular arrhythmias by using a method called Second Order Dynamic Binary Decomposition (SOD-BD) technique. Two significant characteristics (the natural frequency and the input parameter) were extracted from Electrocardiogram (ECG) signals that are provided by Physiobank database and analyzed to find the significant differences for each ventricular arrhythmia types and classify the ECGs accordingly (N, VT and VF). The outcome from these ECG extractions was also used to locate the onset of ventricular arrhythmia that is useful to predict the occurrence of the heart abnormalities. All the ECGs analysis, parameters extraction, classification techniques, and the CODS are developed using LabVIEW software
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