Damping and Mass Sensitivity of Laterally Vibrating Resonant Microcantilevers in Viscous Liquid Media

The effect of liquid viscosity and density on the characteristics of laterally excited microcantilevers is investigated and compared to transversely excited microcantilevers. When immersed into a viscous liquid medium such as water from air, the resonant frequency of laterally (in-plane) vibrating microcantilevers is shown to decrease by only 5-10% as compared to ~50% reduction for transversely (out-of-plane) vibrating microcantilevers. Furthermore, as the viscosity of the medium increases the resonant frequency of a laterally vibrating beam is shown to decrease at a slower rate than that of a transversely vibrating beam. The decreased viscous damping also leads to increases in the quality factor of the system by a factor of 4-5 compared to beams vibrating transversely. The mass sensitivities of laterally vibrating beams are also theoretically predicted to be roughly two orders of magnitude larger in water for some cantilever geometries. The increase in the quality factor and mass sensitivity indicate that operating in the in-plane flexural mode (lateral vibration) will decrease the limit of detection compared to operating in the more common out-of-plane flexural mode (transverse vibration). These improvements in device characteristics indicate that microcantilevers excited laterally are more suited for operating in media of high viscosities

Land-surface parameter optimisation using data assimilation techniques: The adJULES system V1.0

This is the final version of the article. Available from the European Geosciences Union (EGU) via the DOI in this record.Land-surface models (LSMs) are crucial components of the Earth system models (ESMs) that are used to make coupled climate-carbon cycle projections for the 21st century. The Joint UK Land Environment Simulator (JULES) is the land-surface model used in the climate and weather forecast models of the UK Met Office. JULES is also extensively used offline as a land-surface impacts tool, forced with climatologies into the future. In this study, JULES is automatically differentiated with respect to JULES parameters using commercial software from FastOpt, resulting in an analytical gradient, or adjoint, of the model. Using this adjoint, the adJULES parameter estimation system has been developed to search for locally optimum parameters by calibrating against observations. This paper describes adJULES in a data assimilation framework and demonstrates its ability to improve the model-data fit using eddy-covariance measurements of gross primary production (GPP) and latent heat (LE) fluxes. adJULES also has the ability to calibrate over multiple sites simultaneously. This feature is used to define new optimised parameter values for the five plant functional types (PFTs) in JULES. The optimised PFT-specific parameters improve the performance of JULES at over 85% of the sites used in the study, at both the calibration and evaluation stages. The new improved parameters for JULES are presented along with the associated uncertainties for each parameter.This work was supported by the UK Natural Environment Research Council (NERC) through the National Centre for Earth Observation (NCEO). This study used eddy-covariance data acquired by the FLUXNET community and in particular by the following networks: AmeriFlux (US Department of Energy, Biological and Environmental Research, Terrestrial Carbon Program (DE-FG02-04ER63917 and DE-FG02-04ER63911)), AfriFlux, AsiaFlux, CarboAfrica, CarboEuropeIP, CarboItaly, CarboMont, ChinaFlux, Fluxnet-Canada (supported by CFCAS, NSERC, BIOCAP, Environment Canada, and NRCan), GreenGrass, KoFlux, LBA, NECC, OzFlux, TCOSSiberia, USCCC. Support for eddy-covariance data harmonisation was provided by CarboEuropeIP, FAO-GTOS-TCO, iLEAPS, Max Planck Institute for Biogeochemistry, National Science Foundation, University of Tuscia, Université Laval and Environment Canada and US Department of Energy and the database development and technical support from Berkeley Water Center, Lawrence Berkeley National Laboratory, Microsoft Research eScience, Oak Ridge National Laboratory, University of California – Berkeley, University of Virginia. The authors are grateful to T. Kaminski and R. Giering from FastOpt for their contribution to the development of the adjoint model, and to M. Groenendijk, A. Harper, and the UK Met Office for processing and sharing their data. The authors are particularly grateful to two anonymous referees for their thoughtful and constructive reviews, which greatly improved this manuscript

Inner and outer radial density functions in correlated two-electron systems

A method is presented for determining inner and outer one-electron radial density functions for two electron systems by partitioning the fully correlated two-electron radial density function. This is applied to the helium isolectronic series (Z=1 to 10 and 100) and the critical nuclear charge system, which has the minimum charge for which the atomic system has at least one bound state, to separate out the motions of the two electrons in both weakly and strongly correlated systems. It is found that the inner electron experiences an anti-shielding effect due to the perturbation by the other electron which increases with increasing Z. For the weakly bound systems the inner radial density distribution closely resembles that of a hydrogenic atom with the outer radial density distribution becoming very diffuse

Scoping study for a foresight on new and emerging occupational safety and health (OSH) risks and challenges

This report presents findings from the first two elements of a research project commissioned from IES by EU-OSHA to undertake an exercise which will make recommendations about which new emerging OSH trends and challenges are relevant to explore in the next proposed large-scale foresight study, accompanied by recommendations concerning the most suitable methodology. These will then be finalised by EU-OSHA in consultation with its stakeholders

Big business: The private sector market for image and performance enhancing drug harm reduction in the UK

This article draws on three mutually independent ethnographic studies to explore the private sector market for image and performance enhancing drug (IPED) harm reduction in the UK, specifically examining (1) steroid accessory supplements; (2) blood testing services; and (3) bloodletting services. After contextualising the work with a discussion of IPED use and harm reduction and the substantial growth of the global health and fitness industry, each private sector provision is critically interrogated with the following questions in mind: what is the role and utility of these services compared to public sector provision? Why has the private sector begun to deliver IPED harm reduction products and services in the UK? And how does this provision relate to the health and fitness industry more broadly? The paper concludes with some reflections about the future direction of IPED harm reduction, the importance of community-led services, and the need to think innovatively if we are to best protect users’ health and wellbeing

Acoustic Hologram Enhanced Phased Arrays for Ultrasonic Particle Manipulation

The ability to shape ultrasound fields is important for particle manipulation, medical therapeutics, and imaging applications. If the amplitude and/or phase is spatially varied across the wave front, then it is possible to project “acoustic images.” When attempting to form an arbitrary desired static sound field, acoustic holograms are superior to phased arrays due to their significantly higher phase fidelity. However, they lack the dynamic flexibility of phased arrays. Here, we demonstrate how to combine the high-fidelity advantages of acoustic holograms with the dynamic control of phased arrays in the ultrasonic frequency range. Holograms are used with a 64-element phased array, driven with continuous excitation. Movement of the position of the projected hologram via phase delays that steer the output beam is demonstrated experimentally. This allows the creation of a much more tightly focused point than with the phased array alone, while still being reconfigurable. It also allows the complex movement at a water-air interface of a “phase surfer” along a phase track or the manipulation of a more arbitrarily shaped particle via amplitude traps. Furthermore, a particle manipulation device with two emitters and a single split hologram is demonstrated that allows the positioning of a “phase surfer” along a one-dimensional axis. This paper opens the door for new applications with complex manipulation of ultrasound while minimizing the complexity and cost of the apparatus

3D printing for Growth Adaptive Medical Devices: an alternative approach for craniosynostosis

An adaptive medical device is a piece of equipment designed to adjust or respond to changes in a patient’s condition or environment. The use of 3D printing technology for the development of adaptive medical devices has opened up new possibilities for customization, efficiency, and accessibility in healthcare. Sagittal craniosynostosis is a birth defect that arises due to a premature fusion of the sagittal suture in infants. This disease causes a misshapen skull and a rise of intracranial pressure that can lead to cognitive impairments. At six months of age, the preferred technique for craniosynostosis is an open vault remodeling surgery, an extremely invasive procedure with severe blood loss for the patient and significant postoperative pain. In this context, growth adaptive cranial plates, that can be tuned depending on the patient to achieve the desired skull shape through the deformation of the structure, can be a valid alternative. Cellular and lattice structures offer tailorable mechanical properties in relation to the designed geometry. Specifically, the geometry of cellular materials can be modified in relation to the final mechanical requirements. In this study, the predictability of the deformation of a PLA structure composed by honeycomb unit cells was studied performing compression simulations. The geometry was then modified, simulations and compression tests were then repeated in order to find an equation that could describe the relation between the internal angle of the honeycomb and the relative Poisson ratio. This relation can be further exploited for the production of customized adaptive devices for the treatment of sagittal craniosynostosis