College of Science, Engineering and Food Science

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1,3-Dipolar cycloadditions of 2-thio-3-chloroacrylamides with diazoalkanes
(RSC Publishing, 2010-06-21) Kissane, Marie; Lawrence, Simon E.; Maguire, Anita R.; Irish Research Council for Science Engineering and Technology
2-Thio-3-chloroacrylamides undergo 1,3-dipolar cycloadditions with diazoalkanes leading to a series of novel pyrazolines and pyrazoles. The mechanistic and synthetic features of the cycloadditions to the 2-thio-3-chloroacrylamides at both the sulfide and sulfoxide levels of oxidation are rationalised on the basis of the nature of the substituents.
1,3-Dipolar cycloadditions of 2-thio-3-chloroacrylamides with nitrile oxides and nitrones
(Elsevier, 2010-06-19) Kissane, Marie; Lawrence, Simon E.; Maguire, Anita R.; Irish Research Council for Science Engineering and Technology
1,3-Dipolar cycloadditions of 2-thio-3-chloroacrylamides with nitrile oxides and nitrones is described. A series of novel isoxazolines are isolated from the nitrile oxide cycloadditions, whilst the isoxazolines generated from the nitrone cycloadditions undergo further ring opening to yield piperidines.
A 100 year review of electricity policy in Ireland (1916–2015)
(Elsevier Ltd., 2017-02-21) Gaffney, Fiac; Deane, John Paul; Ó Gallachóir, Brian P.; Bord Gáis Energy
Over the past century, Ireland's electricity sector has undergone a significant transformation. This paper documents the nation's struggle to build an electricity system, to improve security of electricity supply through portfolio diversification and to promote indigenous energy sources. This was a challenge for an (electrically) isolated island with little natural resources. The paper also identifies the ineffective policy decisions that left Ireland exposed to the 1970s energy crises. The crises did, however, provide a clear impetus for focusing Irish energy policy going forward. The successful deployment and integration of large-scale wind power was due to strong national and supranational policy decisions. In 2015, Ireland had the third highest wind energy share of national electricity demand (22.8%) of all IEA Wind Member Countries. The paper also traces Ireland's transition through market reform, regional fragmentation, and looks onwards to the EU internal market for electricity. In essence, this paper provides a holistic view of the implications of various policy decisions on the electricity sector along with the stresses of external factors on the electricity market and should be useful for policy makers elsewhere faced with similar decisions.
The 15-43 GHz parsec-scale circular polarization of 41 active galactic nuclei
(Oxford University Press, 2008) Vitrishchak, V. M.; Gabuzda, Denise; Algaba, Juan Carlos; Rastorgueva, E. A.; O'Sullivan, Shane P.; O'Dowd, A.
We present the results of parsec-scale circular-polarization measurements based on Very Long Baseline Array data for a number of radio-bright, core-dominated active galactic nuclei obtained simultaneously at 15, 22 and 43 GHz. The degrees of circular polarization m(c) for the Very Long Baseline Interferometry (VLBI) core region at 15 GHz are similar to the values reported earlier at this wavelength, with typical values of a few tenths of a per cent. We find that mc as often rises as falls with increasing frequency between 15 and 22 GHz, while the degree of circular polarization at 43 GHz is in all cases higher than at 22 and 15 GHz. This behaviour seems contrary to expectations, since the degree of circular polarization from both synchrotron radiation and the Faraday conversion of linear to circular polarization - the two main mechanisms considered thus far in the literature - should decrease towards higher frequencies if the source is homogeneous. The increase in mc at 43 GHz may be due to the presence of regions of both positive and negative circular polarization with different frequency dependences ( but decreasing with increasing frequency) on small scales within the core region; alternatively, it may be associated with the intrinsic inhomogeneity of a Blandford-Konigl like jet. In several objects, the detected circular polarization appears to be near, but not coincident with, the core, although further observations are needed to confirm this. We find several cases of changes in sign with frequency, most often between 22 and 43 GHz. We find tentative evidence for transverse structure in the circular polarization of 1055+018 and 1334-127, that is consistent with their being generated by either the synchrotron mechanism or the Faraday conversion in a helical magnetic field. Our results confirm the earlier finding that the sign of the circular polarization at a given observing frequency is generally consistent across epochs separated by several years or more, suggesting stability of the magnetic-field orientation in the innermost jets.
16S rRNA gene sequencing of mock microbial populations-impact of DNA extraction method, primer choice and sequencing platform
(BioMed Central, 2016-06-24) Fouhy, Fiona; Clooney, Adam G.; Stanton, Catherine; Claesson, Marcus J.; Cotter, Paul D.; Seventh Framework Programme; Science Foundation Ireland
Background: Next-generation sequencing platforms have revolutionised our ability to investigate the microbiota composition of complex environments, frequently through 16S rRNA gene sequencing of the bacterial component of the community. Numerous factors, including DNA extraction method, primer sequences and sequencing platform employed, can affect the accuracy of the results achieved. The aim of this study was to determine the impact of these three factors on 16S rRNA gene sequencing results, using mock communities and mock community DNA. Results: The use of different primer sequences (V4-V5, V1-V2 and V1-V2 degenerate primers) resulted in differences in the genera and species detected. The V4-V5 primers gave the most comparable results across platforms. The three Ion PGM primer sets detected more of the 20 mock community species than the equivalent MiSeq primer sets. Data generated from DNA extracted using the 2 extraction methods were very similar. Conclusions: Microbiota compositional data differed depending on the primers and sequencing platform that were used. The results demonstrate the risks in comparing data generated using different sequencing approaches and highlight the merits of choosing a standardised approach for sequencing in situations where a comparison across multiple sequencing runs is required.
177 dB linear dynamic range pixels of interest DSLR CAOS camera
(Institute of Electrical and Electronics Engineers Inc., 2019-04-04) Riza, Nabeel A.; Mazhar, Mohsin A.
For the first time, demonstrated is an extreme linear Dynamic Range (DR) Pixels of Interest (POI) [i.e., Coded Access Optical Sensor (CAOS)] Digital Single Lens Reflex (DSLR) camera design that engages three different types of photosensors within one optomechanical assembly to smartly identify POI across a one billion to one light irradiance range. A pixelated CMOS sensor provides a limited DR and linearity image by engaging a moveable mirror placed between the Digital Micromirror Device (DMD) and the frontend imaging lens. Next using DMD control, non-POI light is directed away from the chosen point photodetector (PD) engaged for high DR POI image recovery, giving the PD an improved use of quantum well capacity. For brighter POI, a solid state photodiode point PD with an electronic gain controlled amplifier is engaged while for weaker light POI, a photomultiplier tube (PMT) with variable optical gain is deployed. POI imaging is achieved using time-frequency CAOS modes via DMD control and time-frequency correlation and spectral digital signal processing. A 123.4 dB linear DR POI recovery is achieved for a custom incoherent white light 36-patch target while a record 177 dB linear DR recovery is demonstrated for a single patch 633 nm laser target. For the first time, a 1023 POI frame, real-time 48 frames/s update rate CAOS imaging is demonstrated for tracking a changing focal spot moving laser target.
2 pi steradian coverage transmit-receive lasercom system using smart multiplexing of multiplexed optical scanners
(Society of Photo-Optical Instrumentation Engineers (SPIE), 2002-12-09) Yaqoob, Zahid; Riza, Nabeel A.; Defense Advanced Research Projects Agency
Wide area (such as 2pi steradian) coverage transmit-receive lasercom sub-system is proposed. The lasercom subsystem design utilizes recently proposed new beam scanning approach called Multiplexed Optical Scanner Technology (MOST) that promises high-speed reconfiguration, low power consumption, large aperture, and wide coverage desired for agile, low cost, and easy to install free-space optical link system. The stringent sub-system goals are met by introducing the concept of "Multiplexing" at both the scanner interconnection level and the light property level. The scanner interconnections can be parallel or serial or both. The light properties that can be multiplexed include polarization, time, wavelength, space, and spatial codes. Manipulating the mentioned parameters of light, various multiplexed optical scanners (MOSs) can be realized. The highly sought after lasercom sub-system design will consist of two or more MOSs combined together in a smart fashion.Wide area (such as 2pi steradian) coverage transmit-receive lasercom sub-system is proposed. The lasercom subsystem design utilizes recently proposed new beam scanning approach called Multiplexed Optical Scanner Technology (MOST) that promises high-speed reconfiguration, low power consumption, large aperture, and wide coverage desired for agile, low cost, and easy to install free-space optical link system. The stringent sub-system goals are met by introducing the concept of "Multiplexing" at both the scanner interconnection level and the light property level. The scanner interconnections can be parallel or serial or both. The light properties that can be multiplexed include polarization, time, wavelength, space, and spatial codes. Manipulating the mentioned parameters of light, various multiplexed optical scanners (MOSs) can be realized. The highly sought after lasercom sub-system design will consist of two or more MOSs combined together in a smart fashion.
A 2-legged XY parallel flexure motion stage with minimised parasitic rotation
(Sage, 2014-03) Hao, Guangbo
XY compliant parallel manipulators (aka XY parallel flexure motion stages) have been used as diverse applications such as atomic force microscope scanners due to their proved advantages such as eliminated backlash, reduced friction, reduced number of parts and monolithic configuration. This paper presents an innovative stiffness centre based approach to design a decoupled 2-legged XY compliant parallel manipulator in order to better minimise the inherent parasitic rotation and have a more compact configuration. This innovative design approach makes all of the stiffness centres, associated with the passive prismatic (P) modules, overlap at a point that all of the applied input forces can go through. A monolithic compact and decoupled XY compliant parallel manipulator with minimised parasitic rotation is then proposed using the proposed design approach based on a 2-PP kinematically decoupled translational parallel manipulator. Its load–displacement and motion range equations are derived, and geometrical parameters are determined for a specified motion range. Finite element analysis comparisons are also implemented to verify the analytical models with analysis of the performance characteristics including primary stiffness, cross-axis coupling, parasitic rotation, input and output motion difference and actuator nonisolation effect. Compared with the existing XY compliant parallel manipulators obtained using 4-legged mirror-symmetric constraint arrangement, the proposed XY compliant parallel manipulators based on stiffness centre approach mainly benefits from fewer legs resulting in reduced size, simpler modelling as well as smaller lost motion. Compared with existing 2-legged designs with the conventional arrangement, the present design has smaller parasitic rotation, which has been proved from the finite element analysis results.
The 2015 edition of the GEISA spectroscopic database
(Elsevier, 2016-06-23) Jacquinet-Husson, N.; Armante, R; Scott, N. A.; Chedin, A.; Crepeau, L.; Boutammine, C.; Bouhdaoui, A.; Crevoisier, C.; Capelle, V.; Boonne, C.; Poulet-Crovisier, N.; Barbe, A.; Benner, D. C.; Boudon, V.; Brown, L. R.; Buldyreva, J.; Campargue, A.; Coudert, L. H.; Devi, V. M.; Down, Michael J.; Drouin, B. J.; Fayt, A.; Fittschen, C.; Flaud, J. M.; Gamache, R. R.; Harrison, J. J.; Hill, Colin; Hodnebrog, O.; Hu, S. M.; Jacquemart, D.; Jolly, A.; Jimenez, E.; Lavrentieva, N. N.; Liu, A. W.; Lodi, L.; Lyulin, O. M.; Massie, S. T.; Mikhailenko, S.; Muller, H. S. P.; Naumenko, O. V.; Nikitin, A.; Nielsen, C. J.; Orphal, J.; Perevalov, V. I.; Perrin, A.; Polovtseva, E.; Predoi-Cross, A.; Rotger, M.; Ruth, Albert A.; Yu, S. S.; Sung, K.; Tashkun, S. A.; Tennyson, J.; Tyuterev, V. I. G.; Auwera, J. V.; Voronin, B. A.; Makie, A.; Centre National d’Etudes Spatiales; Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique; National Science Foundation; Russian Foundation for Basic Research; Science Foundation Ireland; Horizon 2020; European Commission; Fonds De La Recherche Scientifique - FNRS; Natural Sciences and Engineering Research Council of Canada
The GEISA database (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information) has been developed and maintained by the ARA/ABC(t) group at LMD since 1974. GEISA is constantly evolving, taking into account the best available spectroscopic data. This paper presents the 2015 release of GEISA (GEISA-2015), which updates the last edition of 2011 and celebrates the 40th anniversary of the database. Significant updates and additions have been implemented in the three following independent databases of GEISA. The “line parameters database” contains 52 molecular species (118 isotopologues) and transitions in the spectral range from 10−6 to 35,877.031 cm−1, representing 5,067,351 entries, against 3,794,297 in GEISA-2011. Among the previously existing molecules, 20 molecular species have been updated. A new molecule (SO3) has been added. HDO, isotopologue of H2O, is now identified as an independent molecular species. Seven new isotopologues have been added to the GEISA-2015 database. The “cross section sub-database” has been enriched by the addition of 43 new molecular species in its infrared part, 4 molecules (ethane, propane, acetone, acetonitrile) are also updated; they represent 3% of the update. A new section is added, in the near-infrared spectral region, involving 7 molecular species: CH3CN, CH3I, CH3O2, H2CO, HO2, HONO, NH3. The “microphysical and optical properties of atmospheric aerosols sub-database” has been updated for the first time since 2003. It contains more than 40 species originating from NCAR and 20 from the ARIA archive of Oxford University. As for the previous versions, this new release of GEISA and associated management software facilities are implemented and freely accessible on the AERIS/ESPRI atmospheric chemistry data center website.
2D and 3D photonic crystal materials for photocatalysis and electrochemical energy storage and conversion
(National Institute for Materials Science; Taylor & Francis, 2016-09) Collins, Gillian; Armstrong, Eileen; McNulty, David; O'Hanlon, Sally; Geaney, Hugh; O'Dwyer, Colm; National University of Ireland; Science Foundation Ireland
This perspective reviews recent advances in inverse opal structures, how they have been developed, studied and applied as catalysts, catalyst support materials, as electrode materials for batteries, water splitting applications, solar-to-fuel conversion and electrochromics, and finally as photonic photocatalysts and photoelectrocatalysts. Throughout, we detail some of the salient optical characteristics that underpin recent results and form the basis for light-matter interactions that span electrochemical energy conversion systems as well as photocatalytic systems. Strategies for using 2D as well as 3D structures, ordered macroporous materials such as inverse opals are summarized and recent work on plasmonic–photonic coupling in metal nanoparticle-infiltrated wide band gap inverse opals for enhanced photoelectrochemistry are provided.
2D and 3D vanadium oxide inverse opals and hollow sphere arrays
(Royal Society of Chemistry (RSC), 2014-10-24) Armstrong, Eileen; Osiak, Michal J.; Geany, Hugh; Glynn, Colm; O'Dwyer, Colm; Irish Research Council; Science Foundation Ireland; Seventh Framework Programme
High quality 2D and 3D inverse opals and hollow sphere arrays of vanadium oxide are grown on conductive substrates from colloidal polymer sphere templates formed by electrophoretic deposition or surfactant-assisted dip-coating. Inverse opals (IOs) are formed using variants of solution drop-casting, N2-gun assisted infiltration and high-rate (200 mm min−1) iterative dip-coating methods. Through Raman scattering, transmission electron microscopy and optical diffraction, we show how the oxide phase, crystallinity and structure are inter-related and controlled. Opal template removal steps are demonstrated to determine the morphology, crystallinity and phase of the resulting 2D and 3D IO structures. The ability to form high quality 2D IOs is also demonstrated using UV Ozone removal of PMMA spheres. Rapid hydrolysis of the alkoxide precursor allows the formation of 2D arrays of crystalline hollow spheres of V2O5 by utilizing over-filling during iterative dip-coating. The methods and crystallinity control allow 2D and 3D hierarchically structured templates and inverse opal vanadium oxides directly on conductive surfaces. This can be extended to a wide range of other functional porous materials for energy storage and batteries, electrocatalysis, sensing, solar cell materials and diffractive optical coatings.
2D image classification and alignment in single-particle Cryo-EM
(University College Cork, 2024) ZiJian, Bai; Huang, Jian; O'Sullivan, Finbarr; China Scholarship Council
Background and Objective: Single-particle Cryo-EM is a powerful tool for structural biologists to determine structures of macro-molecules at atomic resolution. In single-particle Cryo-EM, many individual biological molecular particles with identical structures are rapidly frozen at unknown, random orientations, and then imaged by transmission electron microscopy to generate a set of two-dimensional (2D) projection images. These generated images are treated as projections of one particle from various directions and used to reconstruct the 3D structure of the particle. Reconstruction in single-particle Cryo-EM is extremely challenging due to the lack of knowledge on the projection directions and low signal to noise ratios (SNR). To tackle this difficulty, most methods start by estimating an ab-initio model from class-averaged particle images. Then, this initial model is refined iteratively until a high resolution map is obtained, a task named ‘3D refinement’. There are two challenges in reconstructing a 3D particle structure from projection images in single-particle Cryo-EM. One is that as the particles are oriented randomly within the ice, the projection angle of the image is unknown. Another is the very low SNR, it is extremely hard to estimate projection angles. The main reason for the low SNR is the low electron doses allowed to be used for imaging. To improve the SNR in single-particle Cryo-EM, projection images are classified and averaged to generate the class-average images. This thesis focus on identifying and developing methods that can accurately and effectively compute class-averages. Methodology: Two important steps in class averaging are: (1) classifying images with similar viewing directions but with different in-plane rotations; (2) rotation alignment of images in each class. To perform rotation-invariant classification and rotation alignment, we first propose a non-uniform discrete Fourier transform (NUDFT) to calculate the Fourier transform of an image in polar coordinates. Based on the proposed NUDFT, we develop a rotation-invariant feature extraction algorithm. After using principal component analysis to reduce the dimension of the extracted rotation-invariant features and defining a distance between images using their corresponding features, K-means is employed to classify images. We also investigate combining spectral clustering with our NUDFT based rotation-invariant features for the image classification and compare its performance with the K-means. We build an algorithm for estimation of rotation between a pair of images on the base of proposed NUDFT. We also develop a novel spectral clustering method to improve the accuracy of image alignment in the same class. To demonstrate the efficiency of the algorithms, extensive simulations and experiments are performed to compare with rotation-invariant classification and rotation alignment based conventional FT and some existing algorithms in single-particle Cryo-EM. Results and conclusions: The results for the first set of simulation studies show that combining NUDFT with K-means has superior performance in rotation-invariant classification compared with K-means using features extracted by the classical FT and CL2D, displaying enhanced noise resistance, particularly in very low signal-to-noise ratio environments. The second set of simulation studies show that combining NUDFT with spectral clustering can further improve classification performance. In third set of simulation studies, the results show that NUDFT has superior performance in image rotation estimation compared with classical FT, it shows enhanced noise resistance in different SNR levels. The fourth set of simulation studies show that applying spectral clustering and Z-score method on the frequency information generated from NUDFT can further enhanced alignment performance. The overall studies show that NUDFT is effective and efficient in 2D class-averaging, and proposed algorithms can realize the potential of NUDFT and improve its performance.
2D nanosheet paint from solvent-exfoliated Bi2Te3 ink
(American Chemical Society, 2017-08-09) Carroll, Elaine; Buckley, Darragh; Mogili, N. V. V.; McNulty, David; Moreno, M. Sergio; Glynn, Colm; Collins, Gillian; Holmes, Justin D.; Razeeb, Kafil M.; O'Dwyer, Colm; Irish Research Council; Science Foundation Ireland; Consejo Nacional de Investigaciones Científicas y Técnicas; Agencia Nacional de Promoción Científica y Tecnológica; Horizon 2020; Analog Devices; Ministry of Science, Technology, Innovation and Communication, Brazil
Embedding 2D layered materials into polymers and other materials as composites has resulted in the development of ultrasensitive pressure sensors, tunable conductive stretchable polymers, and thermoelectric coatings. As a wettable paint or ink, many 2D materials may be penciled, printed, or coated onto a range of surfaces for a variety of applications. However, the intrinsic conductive properties of painted coatings using 2D and layered materials are not completely understood, and conductive polymer additives may mask underlying properties such as directional conductivity. We report a process for making a paint from solvent-exfoliated Bi2Te3 into solution-dispersible 2D and few-layer (multiple quintuple) nanosheet inks, that form smooth, uniform paint blends at several concentrations of Bi2Te3. The individual solvent-exfoliated nanosheets are edge-coated by (poly)ethylene glycol to produce a paint, stable over extended period in solution. Electrical transport is found to be sensitive to aspect ratio, and conduction along the painting direction is suppressed for longer strips so long as the aspect ratio is high (4–10× or more), but for short and wide paint strips (aspect ratio ≤1), conductance is improved by a factor of 3×. Square 2D paint regions show no clear directional preference for conductance at room temperature but are markedly affected by higher temperatures. Conductivity along a preferential conduction pathway through the nanosheet ensemble is modulated by 2D nanosheet stacking along the direction of paint application for a given aspect ratio. This paint and insights into geometrical 2D composite conduction may have implications for conductive composites, thermoelectrics, and writable circuits using 2D material paints or inks.
360 video DASH dataset
(Association for Computing Machinery, 2023-06-08) Raca, Darijo; Jadhav, Yogita; Quinlan, Jason J.; Zahran, Ahmed H.; Science Foundation Ireland
Different industries are observing the positive impact of 360 video on the user experience. However, the performance of VR systems continues to fall short of customer expectations. Therefore, more research into various design elements for VR streaming systems is required. This study introduces a SW tool that offers straight-forward encoding platforms to simplify the encoding of DASH VR videos. In addition, we developed a dataset composed of 9 VR videos encoded with seven tiling configurations, four segment durations, and up to four different bitrates. A corresponding tile size dataset is also provided, which can be utilised to power network simulations or trace-driven emulations. We analysed the traffic load of various films and encoding setups using the dataset that was presented. Our research indicates that, while smaller tile sizes reduce traffic load, video decoding may require more computational power.
3d absorption-spectra of Sr I through Sr IV
(American Physical Society, 1995) McGuinness, C.; O'Sullivan, G.; Carroll, P. K.; Audley, D.; Mansfield, Michael W. D.
The extreme ultraviolet photoabsorption spectra of neutral to three-times-ionized strontium have been recorded in a comprehensive series of experiments with the dual laser-produced plasma technique. Striking differences were found in the spectra, which can be attributed to the transfer of oscillator strength from 3d→np to 3d→nf transitions at Sr2+ due to nf wave-function contraction. In Sr and Sr+, 3d→5p transitions dominate; in Sr2+, 3d→nf transitions are most intense, while in Sr3+ the 4p subshell opens and 3d→4p transitions are the strongest features. Partial cross sections for 3d→ɛf and 3d→ɛp photoionization were calculated and compared with experiment.
3D modelling of concrete tunnel segmental joints and the development of a new bolt-spring model
(Elsevier Ltd., 2021-01-21) Wang, Fei; Huang, Hongwei; Soga, Kenichi; Li, Zili; National Natural Science Foundation of China
In a segmental metro tunnel, it is widely observed that cracks, water leakage and other structural defects usually appear at segmental joint section of a smaller stiffness than main tunnel segment section. In this study, a 3D finite element analysis was conducted to simulate a typical concrete segmental joint explicitly using 3D continuum elements, and the performance of 3D continuum model was validated against laboratory tests available in literature. Since such continuum model may cost excessive computational time when a large-scale tunnel structure is analysed, a new bolt-spring model was developed to simplify the structural features of concrete segmental joint. In the bolt-spring model, the interaction between bolt and segment was modelled by a set of normal springs and shear springs: the stiffness of the normal springs is mainly determined by the bolt itself, whilst the shear springs take account of bolt-segment friction, interaction and shear resistance of the bolt. In the meanwhile, the interaction between two adjoining tunnel segments is explicitly modelled using contact elements. The proposed bolt-spring model is able to simulate the details of joint deformation and contact pressure between segments more realistically than previously available by conventional methods (e.g. continuous ring, beam-spring model (BSM)), where segment-segment interaction is not explicated modelled. Compared to the continuum model, the bolt-spring model saves up to 90% computational time without compromising numerical accuracy. Furthermore, this paper compared the mechanical behaviour of a concrete joint against that of a cast-iron one with particular emphasis on the development of different bolt-spring models.
3D open-worked inverse opal TiO2 and GeO2 materials for long life, high capacity Li-ion battery anodes
(Elsevier, 2017-10-18) McNulty, David; Lonergan, Alex; O'Hanlon, Sally; O'Dwyer, Colm; Science Foundation Ireland; Irish Research Council
In this short review, we overview some advancements made in Li-ion battery anode development, where the structural arrangement of the material plays an important role. Specifically, we summarise the benefits of 3D macroporous structure imposed the anode material, in order to improve ionic and electronic conductivity in the absence of conductive additives and binders. Two anode materials are overviewed: TiO2 and GeO2. These are either high capacity anode materials or accessible, abundant materials that are capable of very stable and long-term cycling. We have focused this review on 3D inverse opal structures of these anodes and summarise their enhanced behaviour by comparing their performance metrics to a range of nanoscale and porous analogues of these materials.
3D printed rechargeable aqueous and non-aqueous lithium-ion batteries: Evolution of design and performance
(Electrochemical Society, 2023-12-12) Egorov, Vladimir; Gulzar, Umair; O'Dwyer, Colm; Horizon 2020; European Regional Development Fund; Irish Research Council; Enterprise Ireland; Higher Education Authority
Here we describe the modeling and design evolution of vat polimerized (Vat-P) stereolithographic apparatus (SLA) 3D printed coin cell-type aqueous and non-aqueous rechargeable lithium-ion batteries, cases and current collectors. We detail the rationale for design evolution that improved performance, handling and assembly of the printed batteries. Some guidance into the modeling, 3D printing process, material choice, chemical and electrochemical stability, assembly, sealing, and performance of 3D printed Li-ion batteries is outlined. 3D printed Li-ion batteries demonstrated promising results in terms of gravimetric capacity, rate capability, and capacity per unit footprint area compared to conventional coin cells in both aqueous and non-aqueous systems. For aqueous cells, the cell level capacity is a factor of 2–3x higher than similar metal coin cells due to the lighter weight and better rate response. We also outline design requirements for a Vat-P printed battery that are compatible with organic carbonate-based electrolytes, where the cell provides 115 mAh g−1 specific capacity using an LiCoO2–graphite chemistry, which is only ∼20% less than the maximum reversible capacity of LCO. Despite the challenges faced in optimizing the design and materials for 3D printed Li-ion batteries, this study provides valuable information for future research and development.
3D printing of dairy-based ingredients and investigation into Irish consumer acceptance of 3D food printing applications
(University College Cork, 2022-05-05) Ross, Megan M.; Kelly, Alan; Morrison, Alan P.; Crowley, Shane; Mccarthy, Mary; The Lauritzson Foundation
Three-dimensional (3D) food printing is a type of additive manufacture in which foods with certain rheological characteristics are mechanically layered to create 3D structures from a digitally model. 3D food printing can potentially offer consumers a range of benefits, such as personalised nutrition, customisable textures and unique structures and shapes. This multidisciplinary thesis outlines research completed in three key areas: engineering, food science and consumer science, reflecting the importance of evaluating 3D food printing in this holistic manner. The primary objectives of this work was three-fold: (1) to develop a practical 3D food printer design suitable for printing dairy-based ingredients; (2) to identify and develop suitable dairy-based recipes and investigate factors affecting their printability; and (3) to explore determinants of Irish consumer willingness to try 3D food printing applications. The rationale behind two selected 3D food printer designs (Cartesian and Delta), as well as a brief comparison between the functionality of both designs, are reported. The effects of printing parameters (i.e., nozzle diameter, distance to print bed, print speed etc.) on print quality are also discussed. Certain physicochemical factors such as pH and structural protein content were found to significantly affect the printability and texture of a basic processed cheese recipe. Samples with a higher pH (pH 5.8) tended to print less accurate grids and were significantly softer and less gummy, chewy and resilient than those with lower pH (≤ pH 5.6). Printed processed cheese recipes formulated with fresh curd (high structural protein content) resulted in significantly harder prints, yet printed grids inaccurately due to the material dragging during printing. Viscosity profiles were created for each processed cheese recipe using rheological methods and correlated with absolute printing precision values to identify a range of suitable recipes for accurate printing. The effect of various factors on the printability and functionality of Micellar Casein Concentrate (MCC) suspensions was also investigated. Increasing calcium chloride concentration (5 mM) of suspensions lead to significantly harder printed samples, which had lower dissolution and solubility rates than control or printed samples with lower calcium chloride concentration (1 mM). MCC suspensions printed in porous lattice structures were found to dissolve at a quicker rate than those printed in a hemisphere structure due to a higher surface area to volume ratio. An example of possible 3D-printed product concepts demonstrating the potential of MCC as a printing material is presented. In order to achieve a balanced and comprehensive understanding of 3D food printing technology from a number of perspectives, consumer acceptance research was incorporated into this study to compliment the food science and engineering narrative. Using qualitative methods, a series of themes were identified as forming Irish consumers’ perceptions of 3D food printing applications. Consumers’ affinity for naturalness and a strong association for unprocessed, homemade meals were considered barriers to acceptance of 3D-printed foods. As an extension of this study, data from quantitative research further revealed perceived personal relevance as a significant determinant affecting the dependent variable (i.e., willingness to try 3D food printing applications in the food service sector). Trust in science was found to diminish the negative effects of novel food technology neophobia on willingness to try. Potential solutions for negating factors affecting consumer acceptance are also discussed, which may be of benefit to those looking to market 3D food printing applications in the Irish marketplace. The findings from these studies present an opportunity for food sector stakeholders to utilise this knowledge as part of their foundation to build upon and create novel 3D food printer designs and printable formulations which are suitable for acceptance in the consumer market.
3D vanadium oxide inverse opal growth by electrodeposition
(Electrochemical Society, 2015) Armstrong, Eileen; O'Sullivan, Maria; O'Connell, John; Holmes, Justin D.; O'Dwyer, Colm; Science Foundation Ireland
Three-dimensional vanadium pentoxide (V2O5) material architectures in the form of inverse opals (IOs) were fabricated using a simple electrodeposition process into artificial opal templates on stainless steel foil using an aqueous solution of VOSO4.χH2O with added ethanol. The direct deposition of V2O5 IOs was compared with V2O5 planar electrodeposition and confirms a similar progressive nucleation and growth mechanism. An in-depth examination of the chemical and morphological nature of the IO material was performed using X-ray crystallography, X-ray photoelectron spectroscopy, Raman scattering and scanning/transmission electron microscopy. Electrodeposition is demonstrated to be a function of the interstitial void fraction of the artificial opal and ionic diffusivity that leads to high quality, phase pure V2O5 inverse opals is not adversely affected by diffusion pathway tortuosity. Methods to alleviate electrodeposited overlayer formation on the artificial opal templates for the fabrication of the porous 3D structures are also demonstrated. Such a 3D material is ideally suited as a cathode for lithium ion batteries, electrochromic devices, sensors and for applications requiring high surface area electrochemically active metal oxides.

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