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Search results for: coefficient stability
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Comparative study on total nitrogen prediction in wastewater treatment 1 plant and effect of various feature selection methods on machine learning algorithms performance
PublicationWastewater characteristics prediction in wastewater treatment plants (WWTPs) is valuable and can reduce the number of sampling, energy, and cost. Feature Selection (FS) methods are used in the pre-processing section for enhancing the model performance. This study aims to evaluate the effect of seven different FS methods (filter, wrapper, and embedded methods) on enhancing the prediction accuracy for total nitrogen (TN) in the WWTP...
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Study on Dry Sliding Wear and Friction Behaviour of Al7068/Si3N4/BN Hybrid Composites
PublicationHybrid aluminium metal matrix composites have the potential to replace single reinforced aluminium metal matrix composites due to improved properties. Moreover, tribological performance is critical for these composites, as they have extensive application areas, such as the automotive, aerospace, marine and defence industries. The present work aims to establish the tribological characteristics of Al7068/Si3N4/BN hybrid metal matrix...
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Series-Slot-Fed Circularly Polarized Multiple-Input-Multiple-Output Antenna Array Enabling Circular Polarization Diversity for 5G 28-GHz Indoor Applications
PublicationIn this paper, a four-element circularly polarized series-slot-fed multiple-input-multiple-output (MIMO) antenna array with circular polarization diversity is presented. The proposed design utilizes a combination of 45-degree inclined slots and a straight microstrip line feeding technique. The two antennas are designed to operate with the opposite sense of circular polarization (CP). CP is achieved by placing a patch of just about...
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Standard and modified falling mass impact tests on preplaced aggregatefibrous concrete and slurry infiltrated fibrous concrete
PublicationAlthough several studies have been conducted to evaluate the impact response of concrete using theAmerican Concrete Institute (ACI) 544-2R falling mass impact test, the variations in test results are themain drawback of this testing method. This study aims to reduce the variations in experimental impacttest results by introducing two simple test setup modifications; (1) using coarse or fine aggregate bed-ding as an alternative...
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Nonlinear Free and Forced Vibrations of a Hyperelastic Micro/Nanobeam Considering Strain Stiffening Effect
PublicationIn recent years, the static and dynamic response of micro/nanobeams made of hyperelasticity materials received great attention. In the majority of studies in this area, the strain-stiffing effect that plays a major role in many hyperelastic materials has not been investigated deeply. Moreover, the influence of the size effect and large rotation for such a beam that is important for the large deformation was not addressed. This...
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Flow maldistribution and its mitigation in mini heat exchangers
PublicationIn the present paper, a detailed numerical investigation has been carried out to analyze the flow maldistribution in 50 parallel 1 mm x 1 mm rectangular minichannels and 1 mm depth minigap section with rectangular, trapezoidal, triangular or concave mani-folds in Z-type flow configuration (16 different cases). The working medium was ethanol and the mass flow rate was 5×10-4 kg/s. Both sections was heated from the bottom side. Heat...
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Frequency Selective Surface Based MIMO Antenna Array for 5G Millimeter-Wave Applications
PublicationAbstract: In this paper a radiating element consisting of a modified circular patch is proposed for MIMO arrays for 5G millimeter-wave applications. The radiating elements in the proposed 2×2 MIMO antenna array are orthogonally configured relative to each other to mitigate mutual coupling that would otherwise degrade the performance of the MIMO system. The MIMO array was fabri-cated on Rogers RT/Duroid high frequency substrate...
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Computational Complexity and Its Influence on Predictive Capabilities of Machine Learning Models for Concrete Mix Design
PublicationThe design of concrete mixtures is crucial in concrete technology, aiming to produce concrete that meets specific quality and performance criteria. Modern standards require not only strength but also eco-friendliness and production efficiency. Based on the Three Equation Method, conventional mix design methods involve analytical and laboratory procedures but are insufficient for contemporary concrete technology, leading to overengineering...
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Debonding of coin-shaped osseointegrated implants: Coupling of experimental and numerical approaches
PublicationWhile cementless implants are now widely used clinically, implant debonding still occur and is difficult to anticipate. Assessing the biomechanical strength of the bone–implant interface can help improving the understanding of osseointegration phenomena and thus preventing surgical failures. A dedicated and standardized implant model was considered. The samples were tested using a mode III cleavage device to assess the mechanical...
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A Low-Profile Metal-backed Dipole Loaded with Closely Coupled Arc-shaped Open Stubs for On-metal Tag Design with Wide Frequency Tuning Capability
PublicationThis research has presented a single-layer metal-backed dipole antenna, which consists of a feedline loaded with two pairs of closely-coupled arc-shaped open stubs, for designing a metal-mountable tag that features tuning capability over a wide range of frequency. Here, the stubs can generate sufficient inductive reactance for bringing down the tag resonant frequency tunable in both the regulated UHF RFID passbands (North American...
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Assessment of Sewage Molecular Markers: Linear Alkylbenzenes in Sediments of an Industrialized Region in Peninsular Malaysia
PublicationIn this study, the use of linear alkylbenzenes (LABs) was employed to pinpoint the sources of human activity that cause detrimental impacts on the coastal environment and river ecosystems. LABs were detected using GC–MS in sediment samples assembled from Kim Kim River (KKR) and the Port Dickson coast (PDC). To assess the significance of variations in the distribution and concentrations of LABs across the sampling sites, this study...
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Evolution of charge density wave order in continuous solid solutions Lu(Ni1-xCox)C2
PublicationPseudo-ternary solid solutions, Lu(Ni1-xCox)C2 (0 ≤ x ≤ 1), were studied by means of powder X-ray diffraction, differential thermal analysis as well as electrical resistivity and heat capacity measurements. The crystal structure of the Lu(Ni1-xCox)C2 series, as investigated by means of X-ray powder diffraction, is of structure type CeNiC2, space group Amm2, Pearson symbol oS8. The structural analysis reveals a non-monotonous evolution,...
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Improved surface coverage of an optical fibre with nanocrystalline diamond by the application of dip-coating seeding
PublicationGrowth processes of diamond thin films on the fused silica optical fibres (10 cm in length) were investigated at various temperatures. Fused silica pre-treatment by dip-coating in a dispersion consisting of detonation nanodiamond (DND) in dimethyl sulfoxide (DMSO) with polyvinyl alcohol (PVA) was applied. Nanocrystalline diamond (NCD) films were deposited on the fibres using the microwave plasma assisted chemical vapour deposition...
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Seismic damage diagnosis in adjacent steel and RC MRFs considering pounding effects through improved wavelet-based damage-sensitive feature
PublicationThis paper aims to propose complex Morlet (cmorfb-fc) wavelet-based refined damage-sensitive feature (rDSF) as a new and more precise damage indicator to diagnose seismic damages in adjacent steel and Reinforced Concrete (RC) Moment Resisting Frames (MRFs) assuming pounding conditions using acceleration responses. The considered structures include 6- and 9-story steel and 4- and 8-story RC benchmark...
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Oil refinery dusts: morphological and size analysis by TEM
PublicationThe objectives of this work were to develop a means of sampling atmospheric dusts on the premises of an oil refinery for electron microscopic study to carry out preliminary morphological analyses and to compare these dusts with those collected at sites beyond the refinery limits. Carbon and collodion membranes were used as asupport for collection of dust particles straight on transmission electron microscopy (TEM) grids. Micrographs...
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Low temperature growth of diamond films on optical fibers using Linear Antenna CVD system
PublicationIt is not trivial to achieve a good quality diamond-coated fibre interface due to a large difference in the properties and composition of the diamond films (or use coating even) and the optical fibre material, i.e. fused silica. One of the biggest problems is the high temperature during the deposition which influences the optical fibre or optical fibre sensor structure (e.g. long-period gratings (LPG)). The greatest advantage of...
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Determination of MDPBP in postmortem blood samples by gas chromatography coupled with mass spectrometry
PublicationMDPBP (1-(3,4-methylenedioxyphenyl)-2-(1-pyrrolidinyl)-1-butanone) is a new psychoactive substance sold on the black market. It has been a controlled drug of abuse in Poland and China since 2015 as some toxic and fatal cases connected with use of synthetic cathinone derivatives were observed. The fatal case outlined here concerns a 19 year-old man, who was found dead with an envelope containing white powder lying nearby the cadaver....
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Estimation of Stresses in a Dry Sand Layer Tested on Shaking Table
PublicationTheoretical analysis of shaking table experiments, simulating earthquake response of a dry sand layer, is presented. The aim of such experiments is to study seismic-induced compaction of soil and resulting settlements. In order to determine the soil compaction, the cyclic stresses and strains should be calculated first. These stresses are caused by the cyclic horizontal acceleration at the base of soil layer, so it is important...
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In silico modelling for predicting the cationic hydrophobicity and cytotoxicity of ionic liquids towards the Leukemia rat cell line, Vibrio fischeri and Scenedesmus vacuolatus based on molecular interaction potentials of ions
PublicationIn this study we present prediction models for estimating in silico the cationic hydrophobicity and the cytotoxicity (log [1/EC50]) of ionic liquids (ILs) towards the Leukemia rat cell line (IPC-81), the marine bacterium Vibrio fischeri and the limnic green algae Scenedesmus vacuolatus using linear free energy relationship (LFER) descriptors computed by COSMO calculations. The LFER descriptors used for the prediction model (i.e....
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Enhanced-Performance Circularly Polarized MIMO Antenna with Polarization/Pattern Diversity
PublicationDesign of a compact wideband circularly polarized (CP) multiple-input multiple-output (MIMO) antenna with polarization diversity is proposed and characterized for off-body communication. The antenna is based on a simple coplanar waveguide (CPW)-fed monopole extension of the microstrip line. The orthogonal field components required by CP are induced using a simply modified right/left side ground plane. In particular, a stub extending...