Additive manufacturing of advanced ceramics for demanding applications

Interest and investment in additive manufacturing (AM) has been growing exponentially in recent years. Many AM processes for polymers and metals are nearing maturity, however for ceramics there are fewer processes available and they are in their early stages of development, with a significantly narrower material selection. AM offers benefits of light-weighting and increased efficiency through complex functional designs not possible by conventional manufacturing techniques whilst reducing material waste and tooling costs for different components. Ceramic heaters that exhibit positive temperature coefficient of resistance (PTCR) could be fabricated by AM for improved use in automotive and aerospace applications. This project demonstrates the feasibility of using AM to fabricate PTCR heating elements in various shapes and sizes including honeycomb lattice structures with the same material extrusion equipment – thus signifying the flexibility and suitability of AM to manufacture complex heater geometries. The project work traverse through an entire power-to-product processing excursion to achieve a functional prototype PTCR ceramic heater. Barium titanate (BT) and lanthanum/manganese doped barium titanate (BT) based PTCR functional heater elements/structures were fabricated with desirable electrical properties for the first time using additive manufacturing by material-extrusion (robocasting). 3D printed components of varying size and shape, and prototype honeycomb lattices with high density were achieved with comparable and in some cases superior electrical properties. Aqueous, less organic containing (2.5 wt% additives versus 10-30 wt% added typically), eco-friendly ink formulations were developed with suitable rheological properties for 3D printing. For BT prints, the sintered densities of the 3D ceramic parts were found to be >99% TD, this is the highest reported value so far. The rheology of pastes required for robocasting was investigated in detail to understand the effect of dispersant, solids loading and viscofier contents. The rheological characteristics studied included yield stress, viscosity, shear stress, storage modulus and loss modulus. Different BT based PTCR mixtures were investigated through 3D printing, calcination, sintering along with conventional pressing & sintering for comparison. Effect of printing parameters on print quality and print microstructure were investigated. Drying of the prints was investigated as a parameter to allow printing of a wider range of pastes with different viscosity and yield stress. Yield stress of paste formulations and controlled drying were identified as key contributors to the successful 3D fabrication via robocasting. The microstructure, electrical properties and heating characteristics of the printed PTCR components were studied in detail and their thermal stability evaluated using infrared imaging and benchmarked against commercial PTCR heating element. The heating behaviour of the solid and porous 3D printed components was demonstrated to be similar, paving the way for light weight ( ̴47% reduction in weight) heaters suitable for automotive, aeronautical and even astronautical applications and the technique can also lead to significant materials savings during device fabrication. The general applicability of the robocasting-based AM technique augers well for its use to manufacture complex shaped advanced ceramics for demanding applications, for example, in automotive (heaters as described here), healthcare (biomedical implants - personalised dental and hip/knee implants), defence (high frequency, high temperature conformal antenna structures) and energy (battery components) sectors.</div

Effectiveness of stratospheric solar-radiation management as a function of climate sensitivity

If implementation of proposals to engineer the climate through solar-radiation management (SRM) ever occurs, it is likely to be contingent on climate sensitivity. However, modelling studies examining the effectiveness of SRM as a strategy to offset anthropogenic climate change have used only the standard parameterizations of atmosphere–ocean general circulation models that yield climate sensitivities close to the Coupled Model Intercomparison Project mean. Here, we use a perturbed-physics ensemble modelling experiment to examine how the response of the climate to SRM implemented in the stratosphere (SRM-S) varies under different greenhouse-gas climate sensitivities. When SRM-S is used to compensate for rising atmospheric concentrations of greenhouse gases, its effectiveness in stabilizing regional climates diminishes with increasing climate sensitivity. However, the potential of SRM-S to slow down unmitigated climate change, even regionally, increases with climate sensitivity. On average, in variants of the model with higher sensitivity, SRM-S reduces regional rates of temperature change by more than 90% and rates of precipitation change by more than 50%.Engineering and Applied Science

Production of High Quality Syncrude from Lignocellulosic Biomass

[EN] Wood chips were hydrothermally treated in near critical point water in the presence of a catalyst to yield a raw biocrude, containing a wide range of organic components. This product was subsequently distilled to remove its heaviest fraction, which tends to yield chary products if heated above 350 degrees C. The biocrude obtained has an oxygen content of 12wt% and was subsequently hydrotreated to obtain a hydrocarbon stream. Varying the hydrotreatment operating conditions and catalyst yielded a deoxygenated syncrude which quality improved with operation severity. The hydroprocessed stream produced under very mild conditions can be further upgraded in conventional refinery operations while the stream produced after more severe hydrotreatment can be mixed with conventional diesel. This proof of concept was demonstrated with commercial hydrotreating catalysts, operating between 350 and 380 degrees C, 40 to 120bar pressure and 0.5 to 1h(-1) contact time.The authors thank Licella for material and financial support, as well as providing the biocrude used for the hydrotreating experiments. Licella gratefully acknowledges support from the Australian Government in the form of funding as part of the Advanced Biofuels Investment Readiness Program, received through the Australian Renewable Energy Agency (ARENA). Financial support by the Spanish Government-MINECO through program "Severo Ochoa" (SEV 2012-0267), CTQ2015-70126-R (MINECO/FEDER), and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is also acknowledged.Mathieu, Y.; Sauvanaud, LL.; Humphreys, L.; Rowlands, W.; Maschmeyer, T.; Corma Canós, A. (2017). Production of High Quality Syncrude from Lignocellulosic Biomass. ChemCatChem. 9(9):1574-1578. https://doi.org/10.1002/cctc.201601677S1574157899Huber, G. W., & Corma, A. (2007). Synergies between Bio- and Oil Refineries for the Production of Fuels from Biomass. Angewandte Chemie International Edition, 46(38), 7184-7201. doi:10.1002/anie.200604504Huber, G. W., & Corma, A. (2007). Synergien zwischen Bio- und Ölraffinerien bei der Herstellung von Biomassetreibstoffen. Angewandte Chemie, 119(38), 7320-7338. doi:10.1002/ange.200604504U.S. Department of Energy 2016.2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy Volume 1: Economic Availability of Feedstocks. M. H. Langholtz B. J. Stokes L. M. Eaton (Leads) ORNL/TM-2016/160. Oak Ridge National Laboratory Oak Ridge TN. 448p. DOI:10.2172/1271651.Klein-Marcuschamer, D., & Blanch, H. W. (2015). Renewable fuels from biomass: Technical hurdles and economic assessment of biological routes. AIChE Journal, 61(9), 2689-2701. doi:10.1002/aic.14755Maitlis, P. M., & de Klerk, A. (2013). New Directions, Challenges, and Opportunities. Greener Fischer-Tropsch Processes for Fuels and Feedstocks, 337-358. doi:10.1002/9783527656837.ch16De Miguel Mercader, F., Groeneveld, M. J., Kersten, S. R. A., Geantet, C., Toussaint, G., Way, N. W. J., … Hogendoorn, K. J. A. (2011). Hydrodeoxygenation of pyrolysis oil fractions: process understanding and quality assessment through co-processing in refinery units. Energy & Environmental Science, 4(3), 985. doi:10.1039/c0ee00523aGoudriaan, F., & Peferoen, D. G. R. (1990). Liquid fuels from biomass via a hydrothermal process. Chemical Engineering Science, 45(8), 2729-2734. doi:10.1016/0009-2509(90)80164-aPeterson, A. A., Vogel, F., Lachance, R. P., Fröling, M., Antal, Jr., M. J., & Tester, J. W. (2008). Thermochemical biofuel production in hydrothermal media: A review of sub- and supercritical water technologies. Energy & Environmental Science, 1(1), 32. doi:10.1039/b810100kToor, S. S., Rosendahl, L., & Rudolf, A. (2011). Hydrothermal liquefaction of biomass: A review of subcritical water technologies. Energy, 36(5), 2328-2342. doi:10.1016/j.energy.2011.03.013Oasmaa, A., & Czernik, S. (1999). Fuel Oil Quality of Biomass Pyrolysis OilsState of the Art for the End Users. Energy & Fuels, 13(4), 914-921. doi:10.1021/ef980272bElliott, D. C., Biller, P., Ross, A. B., Schmidt, A. J., & Jones, S. B. (2015). Hydrothermal liquefaction of biomass: Developments from batch to continuous process. Bioresource Technology, 178, 147-156. doi:10.1016/j.biortech.2014.09.132http://www.licella.com.au/commercial-demonstration-plant/.L. J.Humphreys (Ignite Energy Resources Pty Ltd) WO Pat. 2011/032202(A1) 2011.T.Maschmeyer L. J.Humphreys (Licella Pty Ltd) WO Pat. 2011/123897(A1) 2011.Wang, W., Yang, Y., Luo, H., Hu, T., & Liu, W. (2011). Amorphous Co–Mo–B catalyst with high activity for the hydrodeoxygenation of bio-oil. Catalysis Communications, 12(6), 436-440. doi:10.1016/j.catcom.2010.11.001Monnier, J., Sulimma, H., Dalai, A., & Caravaggio, G. (2010). Hydrodeoxygenation of oleic acid and canola oil over alumina-supported metal nitrides. Applied Catalysis A: General, 382(2), 176-180. doi:10.1016/j.apcata.2010.04.035Kubička, D., & Kaluža, L. (2010). Deoxygenation of vegetable oils over sulfided Ni, Mo and NiMo catalysts. Applied Catalysis A: General, 372(2), 199-208. doi:10.1016/j.apcata.2009.10.034Huber, G. W., O’Connor, P., & Corma, A. (2007). Processing biomass in conventional oil refineries: Production of high quality diesel by hydrotreating vegetable oils in heavy vacuum oil mixtures. Applied Catalysis A: General, 329, 120-129. doi:10.1016/j.apcata.2007.07.002Anthonykutty, J. M., Van Geem, K. M., De Bruycker, R., Linnekoski, J., Laitinen, A., Räsänen, J., … Lehtonen, J. (2013). Value Added Hydrocarbons from Distilled Tall Oil via Hydrotreating over a Commercial NiMo Catalyst. Industrial & Engineering Chemistry Research, 52(30), 10114-10125. doi:10.1021/ie400790vH. P.Ruyter J. H. J.Annee (Shell Oil Co) US Pat. no. 4670613A 1987.S. Jones et al. Process Design and Economics for the Conversion of Algal Biomass to Hydrocarbons: Whole Algae Hydrothermal Liquefaction and Upgrading PNNL report 23227 2014.Baker, E. G., & Elliott, D. C. (1988). Catalytic Hydrotreating of Biomass-Derived Oils. Pyrolysis Oils from Biomass, 228-240. doi:10.1021/bk-1988-0376.ch021Kubička, D., & Horáček, J. (2011). Deactivation of HDS catalysts in deoxygenation of vegetable oils. Applied Catalysis A: General, 394(1-2), 9-17. doi:10.1016/j.apcata.2010.10.03

Opportunities in upgrading biomass crudes

[EN] An unconventional crude from biomass (biocrude) has been processed to yield a hydrocarbon stream that is not only fully processable in conventional refineries but is already close to the specification of commercial fuels such as transportation diesel. The upgrading of biocrude was carried out with a combination of hydrotreatment and catalytic cracking, yielding middle distillate as the main product.The authors thank Licella for material and financial support, as well as providing the biocrude used for the hydrotreating experiments. Licella gratefully acknowledges support from the Australian Government in the form of funding as part of the Advanced Biofuels Investment Readiness Program, received through the Australian Renewable Energy Agency (ARENA). Financial support by the Spanish Government-MINECO through program "Severo Ochoa" (SEV 2012-0267), CTQ2015-70126-R (MINECO/FEDER), and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is also acknowledged.Mathieu, Y.; Sauvanaud, LL.; Humphreys, L.; Rowlands, W.; Maschmeyer, T.; Corma Canós, A. (2017). Opportunities in upgrading biomass crudes. Faraday Discussions. 197:389-401. https://doi.org/10.1039/c6fd00208kS389401197U.S. Department of Energy. 2016. 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy, Volume 1: Economic Availability of Feedstocks. M. H. Langholtz, B. J. Stokes, and L. M. Eaton (Leads), ORNL/TM-2016/160. Oak Ridge National Laboratory, Oak Ridge, TN. 448ppP. M. Maitlis and A.de Klerk, Greener Fischer-Tropsch Processes for Fuels and Feedstocks, Wiley, 2013, ch. 16De Miguel Mercader, F., Groeneveld, M. J., Kersten, S. R. A., Geantet, C., Toussaint, G., Way, N. W. J., … Hogendoorn, K. J. A. (2011). Hydrodeoxygenation of pyrolysis oil fractions: process understanding and quality assessment through co-processing in refinery units. Energy & Environmental Science, 4(3), 985. doi:10.1039/c0ee00523aGoudriaan, F., & Peferoen, D. G. R. (1990). Liquid fuels from biomass via a hydrothermal process. Chemical Engineering Science, 45(8), 2729-2734. doi:10.1016/0009-2509(90)80164-aPeterson, A. A., Vogel, F., Lachance, R. P., Fröling, M., Antal, Jr., M. J., & Tester, J. W. (2008). Thermochemical biofuel production in hydrothermal media: A review of sub- and supercritical water technologies. Energy & Environmental Science, 1(1), 32. doi:10.1039/b810100kToor, S. S., Rosendahl, L., & Rudolf, A. (2011). Hydrothermal liquefaction of biomass: A review of subcritical water technologies. Energy, 36(5), 2328-2342. doi:10.1016/j.energy.2011.03.013Oasmaa, A., & Czernik, S. (1999). Fuel Oil Quality of Biomass Pyrolysis OilsState of the Art for the End Users. Energy & Fuels, 13(4), 914-921. doi:10.1021/ef980272bhttp://www.licella.com.au/commercial-demonstration-plant/Bridgwater, A. V. (1994). Catalysis in thermal biomass conversion. Applied Catalysis A: General, 116(1-2), 5-47. doi:10.1016/0926-860x(94)80278-5De Miguel Mercader, F., Groeneveld, M. J., Kersten, S. R. A., Way, N. W. J., Schaverien, C. J., & Hogendoorn, J. A. (2010). Production of advanced biofuels: Co-processing of upgraded pyrolysis oil in standard refinery units. Applied Catalysis B: Environmental, 96(1-2), 57-66. doi:10.1016/j.apcatb.2010.01.033Wang, C., Li, M., & Fang, Y. (2016). Coprocessing of Catalytic-Pyrolysis-Derived Bio-Oil with VGO in a Pilot-Scale FCC Riser. Industrial & Engineering Chemistry Research, 55(12), 3525-3534. doi:10.1021/acs.iecr.5b03008Fogassy, G., Thegarid, N., Schuurman, Y., & Mirodatos, C. (2012). The fate of bio-carbon in FCC co-processing products. Green Chemistry, 14(5), 1367. doi:10.1039/c2gc35152hRezaei, P. S., Shafaghat, H., & Daud, W. M. A. W. (2014). Production of green aromatics and olefins by catalytic cracking of oxygenate compounds derived from biomass pyrolysis: A review. Applied Catalysis A: General, 469, 490-511. doi:10.1016/j.apcata.2013.09.036Hughes, R., Hutchings, G. J., Koon, C. L., McGhee, B., Snape, C. E., & Yu, D. (1996). Deactivation of FCC catalysts using n-hexadecane feed with various additives. Applied Catalysis A: General, 144(1-2), 269-279. doi:10.1016/0926-860x(96)00106-8Huber, G. W., O’Connor, P., & Corma, A. (2007). Processing biomass in conventional oil refineries: Production of high quality diesel by hydrotreating vegetable oils in heavy vacuum oil mixtures. Applied Catalysis A: General, 329, 120-129. doi:10.1016/j.apcata.2007.07.002Anthonykutty, J. M., Van Geem, K. M., De Bruycker, R., Linnekoski, J., Laitinen, A., Räsänen, J., … Lehtonen, J. (2013). Value Added Hydrocarbons from Distilled Tall Oil via Hydrotreating over a Commercial NiMo Catalyst. Industrial & Engineering Chemistry Research, 52(30), 10114-10125. doi:10.1021/ie400790vS. Jones , Y.Zu, D.Anderson, R.Allen, D.Elliot, A.Schmidt, K.Albrecht, T.Hart, M.Butcher, C.Drennan, L.Snowden-Swan, R.Davis and C.Kinchin, PNNL report 23227, March 2014Corma, A., González-Alfaro, V., & Orchillés, A. . (2001). Decalin and Tetralin as Probe Molecules for Cracking and Hydrotreating the Light Cycle Oil. Journal of Catalysis, 200(1), 34-44. doi:10.1006/jcat.2001.3181CORMA, A., & ORTEGA, F. (2005). Influence of adsorption parameters on catalytic cracking and catalyst decay. Journal of Catalysis, 233(2), 257-265. doi:10.1016/j.jcat.2005.04.02

Inequalities in children’s mental health prescribing and referrals for specialist mental health services

Peer reviewe

Massive post-starburst galaxies at z > 1 are compact proto-spheroids

We investigate the relationship between the quenching of star formation and the structural transformation of massive galaxies, using a large sample of photometrically-selected poststarburst galaxies in the UKIDSS UDS field. We find that post-starburst galaxies at highredshift (z > 1) show high Sérsic indices, significantly higher than those of active star-forming galaxies, but with a distribution that is indistinguishable from the old quiescent population. We conclude that the morphological transformation occurs before (or during) the quenching of star formation. Recently quenched galaxies are also the most compact; we find evidence that massive post-starburst galaxies (M_ > 1010:5 M_) at high redshift (z > 1) are on average smaller than comparable quiescent galaxies at the same epoch. Our findings are consistent with a scenario in which massive passive galaxies are formed from three distinct phases: (1) gas-rich dissipative collapse to very high densities, forming the proto-spheroid; (2) rapid quenching of star formation, to create the “red nugget” with post-starburst features; (3) a gradual growth in size as the population ages, perhaps as a result of minor mergers

The identification of post-starburst galaxies at z∼1 using multiwavelength photometry: a spectroscopic verification

Despite decades of study, we still do not fully understand why some massive galaxies abruptly switch off their star formation in the early Universe, and what causes their rapid transition to the red sequence. Post-starburst galaxies provide a rare opportunity to study this transition phase, but few have currently been spectroscopically identified at high redshift (z > 1). In this paper, we present the spectroscopic verification of a new photometric technique to identify post-starbursts in high-redshift surveys. The method classifies the broad-band optical–nearinfrared spectral energy distributions (SEDs) of galaxies using three spectral shape parameters (supercolours), derived from a principal component analysis of model SEDs. When applied to the multiwavelength photometric data in the UKIDSS Ultra Deep Survey, this technique identified over 900 candidate post-starbursts at redshifts 0.5 5 angstrem) and Balmer break, characteristic of post-starburst galaxies.We conclude that photometric methods can be used to select large samples of recently-quenched galaxies in the distant Universe

Synthesis of a boronic acid anhydride based ligand and its application in beryllium coordination

The synthesis of a boronic acid anhydride‐based ligand containing one three‐ and one four‐coordinated boron atom is presented. This ligand was successfully employed as a tridentate κ¹N,κ²O‐ligand in the coordination of beryllium chloride and both the ligand and the resulting complex have been structurally characterized. While the boron‐element separations are within the typical range of related homo‐nuclear compounds, the corresponding beryllium‐element distances are rather long, suggesting unexpectedly high electron density at the beryllium center. Incorporation of a beryllium atom in a six‐membered ring causes no more distortion than the corresponding boron atom, suggesting that analogous ligand systems could be used in boron and beryllium coordination chemistry. The generated hetero‐tri‐nuclear complex enables the direct comparison of bond lengths and angles at beryllium and boron atoms in similar coordination environments and can act as a monomolecular model for beryllium borates

Serious mental health diagnoses in children on the child protection register: a record linkage study.

Children with experience of maltreatment, abuse or neglect are known to have a higher prevalence of poor mental health. Child Protection Services identify children most at risk of harm and in need of intervention. Mental healthcare usage in this population is not well understood as registration data is not routinely linked to health records. We undertook data linkage to describe the population on the register, their mental healthcare usage and to calculate age- and sex-specific incidence rates of mental health outcomes. We analysed records from the Aberdeen City Council Child Protection Register and for mental health prescribing and referrals to child and adolescent mental health services (CAMHS) for the NHS Grampian region between 1st January 2012 and 31st December 2022. We identified 1,498 individuals with a Child Protection Register registration, of which 70% were successfully matched to health records. 20% of registrations occurred before birth and the median age of registration was 3 years. 10.1% of children with a registration ever received a mental health prescription, 5.1% for treatment of attention deficit hyperactivity disorder and 1.7% for treatment of depression. 18.9% received a referral to specialist outpatient Child and Adolescent Mental Health Services. Age- and sex- standardised incidence rates for mental health prescribing and referrals are higher for children with a child protection registration compared to the general population. Children identified as being at significant risk of harm and involved with child protection services are at greater risk of seeking or receiving professional mental health support than their peers. Clinical services should investigate additional ways to support this population’s mental well-being as a priority. Efforts to reduce the exposure of children to potentially harmful environments at a societal level should also be pursued

Post-Starburst Properties of Post-Merger Galaxies

Post-starburst galaxies (PSBs) are transition galaxies showing evidence of recent rapid star formation quenching. To understand the role of galaxy mergers in triggering quenching, we investigate the incidence of PSBs and resolved PSB properties in post-merger galaxies using both SDSS single-fiber spectra and MaNGA resolved IFU spectra. We find post-mergers have a PSB excess of 10 - 20 times that relative to their control galaxies using single-fiber PSB diagnostics. A similar excess of ~ 19 times is also found in the fraction of central (C)PSBs and ring-like (R)PSBs in post-mergers using the resolved PSB diagnostic. However, 60% of the CPSBs + RPSBs in both post-mergers and control galaxies are missed by the single-fiber data. By visually inspecting the resolved PSB distribution, we find that the fraction of outside-in quenching is 7 times higher than inside-out quenching in PSBs in post-mergers while PSBs in control galaxies do not show large differences in these quenching directions. In addition, we find a marginal deficit of HI gas in PSBs relative to non-PSBs in post-mergers using the MaNGA-HI data. The excesses of PSBs in post-mergers suggest that mergers play an important role in triggering quenching. Resolved IFU spectra are important to recover the PSBs missed by single-fiber spectra. The excess of outside-in quenching relative to inside-out quenching in post-mergers suggests that AGN are not the dominant quenching mechanism in these galaxies, but that processes from the disk (gas inflows/consumption and stellar feedback) play a more important role.Comment: Accepted in MNRAS on May 12 2023, 19 pages, 15 figures, 4 table