The search for materials that are lightweight and can withstand extreme service conditions has been a major driving force for material development in recent decades. Ceramic materials, while stable at high temperatures and in harsh environments, are limited in their structural applications due to their inherent brittleness and low damage tolerance compared to their metallic materials. An emerging class of materials referred to as micro-architectured materials offer a potential breakthrough to overcome this limitation. Our preliminary experimental results suggest that large-scale 3D micro-architectured materials, even when made from linear elastic brittle parent materials at scales that resemble bulk materials can exhibit extreme damage tolerance. Thus, in this project we propose to develop a deeper understanding of fracture and damage tolerance in a wide variety of micro-architectured materials made from (ceramic/ceramic-like) purely brittle parent materials. Our proposed research is based on two underlying hypotheses: (1) The discrete nature of the 3D micro-architectures either inherently gives rise to crack-bridging, introduces local anisotropy in the fracture toughness or both that leads to the observed extreme damage tolerance of micro-architectured materials made of inherently brittle parent materials. (2) The topological stochasticity in the 3D micro-architectures made of inherently brittle parent materials will result in diffused damage zones and enhanced crack-bridging, leading to further increase in damage tolerance. The specific objectives of our proposal are twofold. First, ascertain the crack growth and damage tolerance mechanisms of large-scale 3D periodic micro-architectures made of linear elastic brittle parent materials. Second, extend the mechanistic understanding of fracture in periodic micro-architectures to stochastic micro-architectures made of brittle ceramic parent materials. This will enable us to test our hypotheses and address several fundamental questions of technological relevance that are raised in this proposal. Our proposed education and outreach plans are also fully integrated with the research plan through a common focus on mechanics of micro-architectured materials. Classical fracture mechanics has been a highly successful theory for analyzing fracture of continuum materials. However, our preliminary results indicate that these concepts do not directly extend to discrete 3D micro-architectured materials, even those made of purely linear-elastic brittle parent materials. In particular, the discreteness of the microstructure renders standard measures of fracture properties and fracture testing protocols inadequate. This project will expand upon the traditional understanding of classical fracture mechanics and associated testing protocols by developing a comprehensive mechanistic understanding of damage tolerance and devising a novel methodology to characterize fracture response of a wide variety of 3D micro-architectured materials made from purely brittle materials. Furthermore, by gaining a deeper understanding of the correlation between micro-architecture and fracture response, we will create fracture mechanism and performance maps that can be used for selecting an optimum micro-architecture based on parameters such as size and density of the structure and loading conditions. The project's main impact lies in the development of a methodology that will enable the discovery, design, and development of lightweight, damage-tolerant micro-architectured materials for extreme loading conditions. These materials have potential uses not only in structural applications but also in relevant contemporary technologies such as energy, biomedical and micromechanical devices. This project will facilitate damage tolerance and structural integrity analysis for reliable use of micro-architectured materials in these highly sought-after technologies.

Acoustic communication is widespread across the animal kingdom. For decades, studies of acoustically communicating animals have collectively revealed the intricate interplay and co-evolution between signal sender and receiver, as well as the diversity of morphological structures involved in hearing and sound production and their complex neurophysiological underpinnings. However, the current approach in the field of bioacoustics is often narrowly focused on a particular aspect of acoustic communication using single model organisms, making it challenging to draw a general conclusion about how singing and hearing have been shaped through time. This project will take an explicitly clade-based approach using a comprehensive dated phylogeny of Ensifera, the most diverse group of acoustically communicating animals, complemented with cutting-edge techniques in imaging, biophysics, and functional genomics to evaluate mechanisms of hearing and singing in a comparative framework. The ambitious scope of the proposed phylogenomic analysis will firmly establish evolutionary relationships among and within the major ensiferan lineages, which have remained elusive for many decades. The project will generate an unprecedented amount of detailed morphological, biophysical, and genetic data using X-ray micro and nano computed tomography, microscanning laser Doppler vibrometry, RNA-seq, and target capture sequencing. The results from this project will answer outstanding questions about when acoustic communication originated and how often it has been lost, how lineages independently evolved different mechanisms of hearing and signalling, what the physical, neural and genetic bases of these are, and how signal diversity is causally related to diversification and speciation. These findings will collectively reveal general insights about the evolution of acoustic communication.

We know some vehicles are bad emitters, i.e., they are continuous or intermittent high emitters of one or more priority pollutant. We do not know exact numbers, but we suspect some are poorly engineered vehicles, some are deliberately tampered vehicles and some are incorrectly or unmaintained vehicles [1]. Vehicle Emissions Remote Sensing Systems (VERSSs) provide a measure of across-fleet emissions and have often been used to generate '20% of fleet cause 80% of emissions' headlines [see e.g. 2,3]. However, they give a 'snap-shot' measurement that most likely misassigns both occasional high emissions from otherwise properly functioning emissions systems as bad vehicles, and better measurements from vehicles with failing emissions systems as good vehicles [4]. The unknown scale of such false-negatives and false-positives prevents us from using such techniques to do what we would most like to, namely to reliably target individual vehicles. Elsewhere, others have already begun to look at alternative techniques, for example both California ARB and Texas COG have instigated work on other passing vehicle emissions monitoring methods like OHMS and PEAQS [5,6]. Both are high-volume active air sampling methods that trade by comparison to VERSSs, reduced fleet capture rates for longer duration but therefore more representative measures of passing vehicle emissions. While these techniques improve confidence, they are still limited by fixed-point deployment, limiting our ability to engine-load profile emissions. Car-chaser vehicle that include on-board monitors configurated to measure the emissions of other followed vehicles, although out of favour for conventional monitoring activities, could provide us with a better option to target and optimise evidence gathering elements of our efforts to identify and take action against the highest emitting vehicles on our roads. Therefore, the objectives here are two-fold: (1) To explore options to enhance our understanding of high emitters, through the focused analysis of US EPA emission archives, which TTI have access to via established Research Collaboration Agreement. And (2), To repurpose and redeploy conventional in-vehicle emissions measurement systems for car-chaser work focused on the characterisation of followed-vehicle emissions as good or bad, with an aim of scoping the potential for such systems for a role in (near-term) future emissions reduction policy. References: [1] Ligterink, N., 2017. Real-world Vehicle Emissions. International Transport Forum Discussion Paper 2017-06. [2] Pujadas, M., Dominguez-Saez, A. and De la Fuente, J., 2017. Real-driving emissions of circulating Spanish car fleet in 2015 using RSD Technology. Science of the Total Environment, 576, pp.193-209. [3] Wang, J.M., Jeong, C.H., Zimmerman, N., Healy, R.M., Wang, D.K., Ke, F. and Evans, G.J., 2015. Plume-based analysis of vehicle fleet air pollutant emissions and the contribution from high emitters. Atmospheric Measurement Techniques, 8(8), p.3263. [4] Huang, Y., Organ, B., Zhou, J.L., Surawski, N.C., Hong, G., Chan, E.F. and Yam, Y.S., 2018. Remote sensing of on-road vehicle emissions: Mechanism, applications and a case study from Hong Kong. Atmospheric Environment. 182, 58-74. [5] Bishop, G.A., Hottor-Raguindin, R., Stedman, D.H., McClintock, P., Theobald, E., Johnson, J.D., Lee, D.W., Zietsman, J. and Misra, C., 2015. On-road heavy-duty vehicle emissions monitoring system. Environmental science & technology, 49(3), pp.1639-1645. [6] Smith, J.D., Ham, W., Burnitzki, M., Downey, S., Howard, C., Quiros, D., Hu, S., Chernich, D., Huai. 2018. Quantification of HD in-use Vehicles using the Portable Emissions AcQuisition System (PEAQS). 28th CRC Real World Emissions Workshop March, 18th-21st, 2018, Anaheim, California, US.

A range of researcher-based activities, including researcher exchanges between the University of Nottingham, Imperial College and Texas A&M University, workshops and research seminars, will be used to develop international and cross-disciplinary collaboration in the field of pavement engineering materials. The strategic areas of adhesion and the physicochemical interfacial properties of bitumen and aggregate, and the micro-structural characterisation of asphalt materials will form the basis for the research activities. Two-way researcher exchanges will form the main component of the activities and provide researchers with the opportunity to work closely with other international research groups as well as inter-disciplinary groups. The face-to-face dialogue that will be possible with these extended research visits will allow researchers the unique opportunity to identify research challenges and develop innovative approaches and research solutions to the various issues associated with the performance of pavement materials.

The proposal is concerned with studying vertically structured nanocomposite (VSCN) films which can give better physical properties compared to single layer or multilayer films. Under a currently funded proposal together, we have demonstrated several remarkable functional enhancements as well as interesting spontaneously ordered structures (nanocheckerboards) and unprecendented levels of strain in thick film. In particular, we have shown that an important ferroelectric material can be made to work well at several hundred degrees above its normal operation temperature. We believe this is the beginning of the road for the field and there are many new things still to be explored and discovered. We aim to continue with this exploration together. Basic science will be undertaken to understanding of the limitations to the level of strain, the interface compatibilities, and the lateral ordering. New systems will grown and explored to demonstrate the power of the VSCN method, and finally demonstrations of the functional applicability of the strongly enhanced BaTiO3 system will be carried out.