95 research outputs found
An Empirical Study and Analysis of Various Electroencephalography (EEG) Artefact Removal Methods
No full textInvestigation of Quasi-Static Indentation Response of Inkjet Printed Sandwich Structures under Various Indenter Geometries
No full textThe objective of this investigation was to determine the quasi-static indentation response and failure mode in three-dimensional (3D) printed trapezoidal core structures, and to characterize the energy absorbed by the structures. In this work, the trapezoidal sandwich structure was designed in the following two ways. Firstly, the trapezoidal core along with its facesheet was 3D printed as a single element comprising a single material for both core and facesheet (type A); Secondly, the trapezoidal core along with facesheet was 3D printed, but with variation in facesheet materials (type B). Quasi-static indentation was carried out using three different indenters, namely standard hemispherical, conical, and flat indenters. Acoustic emission (AE) technique was used to capture brittle cracking in the specimens during indentation. The major failure modes were found to be brittle failure and quasi-brittle fractures. The measured indentation energy was at a maximum when using a conical indenter at 9.40 J and 9.66 J and was at a minimum when using a hemispherical indenter at 6.87 J and 8.82 J for type A and type B series specimens respectively. The observed maximum indenter displacements at failure were the effect of material variations and composite configurations in the facesheet.ASTAR (Agency for Sci., Tech. and Research, S’pore)Published versio
Quasi-static indentation and sound-absorbing properties of 3D printed sandwich core panels
No full textThe use of 3D printing to produce acoustic panels with good mechanical and acoustic properties was investigated in this paper. Various fiber layups of the fiberglass face sheet and core designs were fabricated and tested for their indentation resistance and acoustic absorption performance. It was found that the bidirectional face sheet layup exhibited the best indentation energy absorption recording 4.2 J, which is 37% more than the 45-degree layout and 66% more than the quasi-isotropic layup. The specific energy absorption of the hybrid honeycomb core is the best among the three core designs recording 404 J/kg, which is 56% higher than the corrugated triangle with horizontal beam core (359 J/kg) and 20% higher than double ellipse core (335 J/kg). Computed-Tomography (CT) scan was used to study the fracture behavior of the sandwich structures. It was found that the bidirectional layup exhibited a different failure mode as compared to the 45-degree and quasi-isotropic layup. In terms of the acoustic properties, the face sheets with various layup patterns have a low acoustic absorption coefficient with minimal differences from each other at low frequencies (500 Hz–3000 Hz) and have higher absorption coefficients with greater differences from each other at frequencies between 3000 Hz–6500 Hz. The absorption curve was significantly affected by the design of the core. The orientation of the core also comes into play if the core is asymmetrical. The hybrid honeycomb sandwich structure was the optimal structure among the three designs for balanced indentation resistance and acoustic insulation.National Research Foundation (NRF)This research is supported by the National Research Foundation, Prime Minister's Office, Singapore under its Medium-Sized Centre funding scheme
Prediction of Absorption Spectrum Shifts in Dyes Adsorbed on Titania
Get PDFDye adsorption on metal-oxide films often results in small to substantial absorption shifts relative to the solution phase, with undesirable consequences for the performance of dye-sensitized solar cells and optical sensors. While density functional theory is frequently used to model such behaviour, it is too time-consuming for rapid assessment. In this paper, we explore the use of supervised machine learning to predict whether dye adsorption on titania is likely to induce a change in its absorption characteristics. The physicochemical features of each dye were encoded as a numeric vector whose elements are the counts of molecular fragments and topological indices. Various classification models were subsequently trained to predict the type of absorption shift i.e. blue, red or unchanged (|Δλ| ≤ 10 nm). The models were able to predict the nature of the shift with a good likelihood (~80%) of success when applied to unseen data.publishedVersionOpen Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Structure, morphology and electrical properties of graphene oxide: CuBiS reinforced polystyrene hybrid nanocomposites
No full text3D-SURFER: Software for high-throughput protein surface comparison and analysis
Get PDFSummary: We present 3D-SURFER, a web-based tool designed to facilitate high-throughput comparison and characterization of proteins based on their surface shape. As each protein is effectively represented by a vector of 3D Zernike descriptors, comparison times for a query protein against the entire PDB take, on an average, only a couple of seconds. The web interface has been designed to be as interactive as possible with displays showing animated protein rotations, CATH codes and structural alignments using the CE program. In addition, geometrically interesting local features of the protein surface, such as pockets that often correspond to ligand binding sites as well as protrusions and flat regions can also be identified and visualized. © The Author 2009. Published by Oxford University Press. All rights reserved
Out Of Plane Compressive Strength Of 3D Printed Vertical Pillared Corrugated Core Structure
No full textOut of plane compressive strength of the two new type 3D printed sandwich core structure has been investigated. The test specimens were designed in Solidworks and manufactured in Projet 5500X 3D printing machine with the combination of pure ABS and Rubber (Visijet CR-WT & Visijet CF-BK) material for making the sandwich core panel. Two design smaples, each of 5 test specimen were carried out for flatwise compression test in accordance with ASTM standards C365/C365-M. The experimental results would indicate the ultimate flatwise compressive strength Fzfcu and flatwise compressive modulus Ezfc.ASTAR (Agency for Sci., Tech. and Research, S’pore)Published versio
Investigation Of Quasi Static Indentation On 3D Printed Honeycomb Based Truncated-pyramid Square Structure
No full textThis research work presents the experimental, and numerical investigation of the Quasi-static indentation behavior of 3D printed honeycomb-based truncated pyramid square Structures. The truncated pyramid square structure was selected for analysis because of its high load bearing capacity. The quasi-static indentation test was carried out in accordance with ASTM D7766/D7766M standards. Force versus displacement curves obtained from the experiments were discussed. By this research, the damage diameter created by the indenter were arbitrary and had no relationship with the material property. Computational simulation was performed to compare with the experimental test results.ASTAR (Agency for Sci., Tech. and Research, S’pore)Published versio
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