Benefiting from biomimicry through 3D printing to enhance mechanical properties of polymeric structures: Simulation approach

© 2023 Aberystwyth University.Numerous biological structures have intricate compositional arrangements, well-organised pieces and stronger mechanical qualities than the materials that make them up. Therefore, this study focused on enhancing the mechanical characteristics of three-dimensional (3D)-printed acrylonitrile butadiene styrene (ABS) structures. Selected parts/systems of three natural (animal/plant) materials were designed/modelled and analysed to mimic their natural lattice structures (biomimicry), using CATIA V5 and finite element method/Ansys software. The simulation results showed that the tensile strength of the biomimetic-designed beetle increased by 13.63%, the bending strength of the biomimetic lotus stem improved by 2.00 and 19.86% in simple and three-point bending tests, and the compressive strength of biomimetic trabecular bone enhanced by 87.59%, when compared with their conventional structures. Also, the biomimetic design recorded 10.00% higher compressive strength than a fillet design and nearly 64.00% than the repeated pattern. It was evident that biomimetic designs enhanced the mechanical properties of all the 3D-printed ABS structures

Analysis on corrosion resistant of electrodeposited ternary Co-W-P alloy

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The interest in the electrodeposition of tungsten-rich binary and ternary alloys has increased in recent years due to their unique combination of electrical, tribological, electro-erosion and magnetic properties. A novel ternary alloy of Cobalt-Tungsten-Phosphorus (Co-W-P) for electroplating and operational parameters were proposed and optimised to give the best corrosion resistance. The development of a stable bath with relatively low pH levels and the use of complexing agents to stabilise it is critical to obtaining good quality films to increase its lifetime. The surface methodology and response were used as optimisation tools. The baths used for achieving this league without complexing agents were unstable. Analysis of the microstructure of the composite particle evaluates the 3D surface luminance structure and the profile structure of the electrodepositions of corrosion resistant of Co-W-P Alloy. Transverse-sectional views of the specimens were extracted and analysed, and the surface roughness, waviness profile, and Gaussian filter of the structures Co-W-P alloy were observed. Good quality Co-W-P alloy films were obtained using an electrochemical bath with the complexing agent. The coatings showed good adhesion on gloss. The characterisation of alloy morphology was performed using spectrometer fluorescence,Power Spectrum Density (PSD) and scanning electron microscopy (SEM). The excellent operating conditions for obtaining this film were a current density of 6 mA/cm 2 and pH 4.0

Model design of a superconducting quantum interference device of magnetic field sensors for magnetocardiography

Collaboration between De Montfort University and University of Leicester, Leicester, UK The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.In recent years, there has been an increase in the study of magnetocardiography (MCG), complementary to electrocardiography (ECG) research, with the purpose of increasing accuracy in the diagnosis of heart and brain pathologies. This research proposes the physical infrastructure of an advanced technology that can be used to obtain heart and brain signals from a specifically designed magnetic field. A generated magnetic sensor is proposed to sense weak magnetic fields in order to detect magnetic heart and brain activity, using interferometry methods. The method of detection of the magnetic field in the sensor, known as a superconducting quantum interference device (SQUID), is found in the interference that occurs during transmission of feeding currents, and the induced currents in the sensor. The sensor consists of two Josephson junctions, connected in parallel. This research presents a fabrication method and the characteristics of thin superconducting films, as an advance in the construction of a SQUID sensor. An ablation chamber is designed, and the deposition of the superconductor on a copper substrate is explored, to obtain thin films at lower cost. The results obtained show good characteristics of superconductivity which can produce a good quality magnetic sensor. There is an intention to further decrease the roughness of the material for the photo lithography process

Long Memory and Time Trends in Particulate Matter Pollution (PM2.5 1 and PM10) in the US States.

This paper focuses on the analysis of the time series behavior of the air quality in the 50 U.S. states by looking at the statistical properties of particulate matter (PM10 and PM2.5) datasets. We use long daily time series of outdoor air quality indices to examine issues such as the degree of persistence as well as the existence of time trends in data. For this purpose, we use a long-memory fractionally integrated framework. The results show significant negative time trend coefficients in a number of states and evidence of long memory in the majority of the cases. In general, we observe heterogeneous results across counties though we notice higher degrees of persistence in the states on the west with respect to those on the east, where there is a general decreasing trend. It is hoped that the findings in the paper will continue to assist in quantitative evidence-based air quality regulation and policies.pre-print857 K

3D printing and morphological characterisation of polymeric composite scaffolds

© 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/.3D-printing is an efficient method of designing customised structures and producing synthetic bone grafts appropriate for bone implants. This research aimed to manufacture a new multi-functionalised 3D-printed poly(lactic acid)/carbonated hydroxyapatite (PLA/cHA) scaffolds with mass proportions of 100/0, 95/5 and 90/10 in a bid to verify their potential application in tissue regeneration. The filaments of these hybrid materials were obtained by extrusion technique and subsequently used to manufacture the 3D-printed scaffolds, using a fused deposition modelling (FDM) technique. The scaffolds were characterised based on their thermal properties, microstructure and geometry by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), respectively, in addition to determination of their apparent porosities. The degradation of the scaffolds and the liberation of degradation products were evaluated in in vitro for different days under simulated physiological conditions. New microanalyses of mechanical behaviour of the materials: tensile and compression stresses, density, frequency analysis and optimisation with DSC were performed. While, evaluation of the surface luminance structure and the profile structure of the nanostructured PLA composite materials was done by SEM, in 3D printed form. The filter profile of cross-sectional view of the specimen was extracted and evaluated with Firestone curve of the Gaussian filter; checking the roughness and waviness profile of the structure. It was observed that the thermal properties of the composites were not affected by the manufacturing process. The microstructural analysis showed the effective incorporation of the ceramic filler in the polymer matrix as well as an acceptable PLA/cHA interaction. The degradation tests showed the presence of calcium and phosphorus in the studied medium, confirming their liberation from the composites during the incubation periods.Peer reviewedFinal Accepted Versio

Analytical modelling of in-situ layer-wise defect detection in 3D Printed parts: Additive Manufacturing

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This study analyses a software algorithm developed on MATLAB, which can be used to examine fused filament fabrication-based 3D printed materials for porosity and other defects that might affect the mechanical property of the final component under manufacture or the general aesthetic quality of a product. An in-depth literature review into the 3D printed materials reveals a rapidly increasing trend in its application in the industrial sector. Hence the quality of manufactured products cannot be compromised. Despite much research found to be done on this subject, there is still little or no work reported on porosity or defect detection in 3D printed components during (real-time) or after manufacturing operation. The algorithm developed in this study is tested for two different 3-D object geometry and the same filament color. The results showed that the algorithm effectively detected the presence or absence of defects in a 3D printed part geometry and filament colors. Hence, this technique can be generalized to a considerable range of 3-D printer geometries, which solve material wastages by spotting defects during the workpieces layer-wise manufacturing process, thereby improving the economic advantages of additive manufacturing

Case Report: Unilateral post-tuberculosis lung destruction and massive haemoptysis in pregnancy with successful outcome

Post-tuberculosis destroyed lung is a fatal complication of pulmonary tuberculosis which can manifest with severe life-threatening haemoptysis. Its occurrence during pregnancy is rare and challenging because of the significant risk to both the mother and the foetus. We present an unbooked 36 year old G6P4+1 (4 alive) woman who presented with chronic cough, massive haemoptysis and multiple pregnancy (twin) at 35 week gestation. She had completed anti-tuberculosis treatment twice at and over nine years prior to presentation. On evaluation, there were clinical and radiological evidences of unilateral (right) destroyed lung but no evidence of active tuberculosis; resuscitation was with antibiotics, blood transfusion and oxygen therapy followed by an emergency caesarean delivery due to significant maternal compromise. The  symptoms resolved following antibiotic therapy and she was subsequently discharged home. Post-tuberculosis destroyed lung is a fatal uncommon condition that may present during pregnancy and requires a multi-disciplinary specialist care to ensure good maternal and foetal outcome. Keywords: Unilateral post-tuberculosis lung destruction; Massive haemoptysis; Twin pregnanc

3D printing of bone scaffolds with hybrid biomaterials

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.In this research, a novel hybrid material bone implant manufacturing through the integration of two materials using additive manufacturing (AM) technology is proposed. Biomimetic application can manufacture high strength biomechanical implants with optimised geometry and mass. The combination of polymers allows a significant leap in the development and production of a great diversity of components and applications of biomaterials. A novel hybrid scaffold with a poly lactic acid (PLA) matrix reinforced with carbohydrate particles (cHA) is analysed using digital surface software in the mass proportions of 100/0, 95/5, 90/10 and 80/20 for application in tissue and regenerative engineering, seeking a higher proposition strength of PLA. Filaments are used to fabricate scaffolds by 3D printing, using the fused deposition method. The frameworks are submitted to bioactivity tests, surface roughness evaluation, apparent porosity and mechanical analysis. Analysis of the microstructure of the composite particle evaluates the 3D surface luminance structure and the profile structure. Cross-sectional views of the specimens are extracted and analysed, and the surface roughness, waviness profile, and Gaussian filter of the structures are observed. In summary the structures are checked and analysed by SEM and EDS where possible, to observe the bioactive behaviour of the materials. The relationship between cHA content and roughness is shown to be proportional. The mechanical properties are shown to be affected by the reduced interaction between the PLA matrix and the cHA particle