Equation of state and electron localisation in fcc lithium
Abstract not provided
36 MATERIALS SCIENCE↗
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Mechanically induced localisation of SECONDARY WALL INTERACTING bZIP is associated with thigmomorphogenic and secondary cell wall gene expression
Plant growth requires the integration of internal and external cues, perceived and transduced into a developmental programme of cell division, elongation and wall thickening. Mechanical forces contribute to this regulation, and thigmomorphogenesis typically includes reducing stem height, increasing stem diameter, and a canonical transcriptomic response. We present data on a bZIP transcription factor involved in this process in grasses. Brachypodium distachyon SECONDARY WALL INTERACTING bZIP (SWIZ) protein translocated into the nucleus following mechanostimulation. Classical touch-responsive genes were upregulated in B. distachyon roots following touch, including significant induction of the glycoside hydrolase 17 family, which may be unique to grass thigmomorphogenesis. SWIZ protein binding to an E-box variant in exons and introns was associated with immediate activation followed by repression of gene expression. SWIZ overexpression resulted in plants with reduced stem and root elongation. These data further define plant touch-responsive transcriptomics and physiology, offering insights into grass mechanotranduction dynamics.
Coomey, Joshua↗
Spatial localisation of Discoidin Domain Receptor 2 (DDR2) signalling is dependent on its collagen binding and kinase activity
Discoidin Domain Receptor 2 (DDR2) is a collagen-binding receptor tyrosine kinase that initiates delayed and sustained tyrosine phosphorylation signalling. To understand the molecular basis of this unique phosphorylation profile, here we utilise fluorescence microscopy to map the spatiotemporal localisation of DDR2 and tyrosine phosphorylated proteins upon stimulation with collagen. We show that cellular phosphorylated proteins are localised to the interface where DDR2 is in contact with collagen and not in the early endosomes or lysosomes. We find that DDR2 localisation is independent of integrin activation and the key DDR2 signalling effector SHC1. Structure-function analysis reveals that DDR2 mutants defective for collagen binding or kinase activity are unable to localise to the cell surface, demonstrating for the first time that both collagen binding and kinase functions are required for spatial localisation of DDR2. This study provides new insights into the underlying structural features that control DDR2 activation in space and time.
60 APPLIED LIFE SCIENCES↗
The Utility of Penile Bulb Contouring to Localise the Prostate Apex as Compared to Urethrography
High-precision radiotherapy relies on accurate anatomic localisation. Urethrography is often used to localise the prostatic apex. However, urethrography is an invasive localisation procedure and may introduce a systemic error. The penile bulb (PB) is contoured to minimise the risk of erectile dysfunction. The purpose of this study is to assess the value of using the PB, as an alternative to urethrography, to localise the prostate.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Fabrication of localised aluminium foam by a novel polymeric blowing agent
Highlights: • Polymeric blowing agent used to synthesize metallic foam for first time. • Localised region of a metallic part is foamed. • A novel semisolid route is used to control the pore size of the foams. • Heat-treatable foam with controllable absorption energy is obtained. - Abstract: Closed cell aluminium foams are highly pursued, due to their unique combination of properties. However, the current applicability of the aluminium foams is limited due to issues like high costs, density-gradient and brittleness of the cell walls, which are either related to use of metallic hydride as blowing agent or liquid-state processing. To address these issues, this study presents a first attempt to use polymer as a blowing agent to foam an aluminium alloy. A polymer is Poly (methyl hydro siloxane) was dispersed into an Al2024 sheet of 6 mm by Friction Stir Processing, in a localised region. This processed sample was pyrolysed at temperatures between solidus and liquidus (500–640 °C) of the alloy and at various durations (5–60 min) to foam the localised precursor. The density of resulting foams was measured by the Archemidies method and the resulting pore structures were characterised by Scanning Electron Microscopy (SEM) and micro X-ray Computed Tomography (CT). The results show that by as pyrolysis temperature increases relative density reaches a minimum of 0.65 at 560 °C. Beyond 590 °C, relative density increased from the optimum due to escape of foaming gasses. With increasing pyrolysis temperature, the pore size increased from few microns to several hundred microns. Further, quasi-static compression test was done on as processed, solutionized and aged foams. Due to increased strain hardening in aged samples energy absorbed during compression increased by 80% in the plateau region. Hence, polymeric a blowing agent can be used to synthesize heat-treatable foams with controllable absorption energy.
36 MATERIALS SCIENCE↗
Efficient two-dimensional sub-wavelength atom localisation via probe absorption in a four-level Λ-shaped atomic system
Two-dimensional (2D) atom localisation of a four-level Λ-shaped atomic system with a nearly hyper-fine doublet interacting with two orthogonal standing-wave fields is investigated. The spatial information of a moving atom in xy plane is obtained by measuring the probe field absorption. The effect of quantum interference on two-dimensional atom localisation is described. The intensity of standing-waves and the detuning of the probe and standing-wave fields are found to strongly affect the two-dimensional atom localisation that lead to different spatial distribution patterns. (paper)
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Surface localisation of laser photoelectron emission using Cu{sub 2}O and Ag film structures
A laser electron source localised on a photocathode surface was developed on the basis of Ag and Cu{sub 2}O thin films sequentially deposited by magnetron sputtering on a glass substrate. Photoemission of electrons under the action of the fourth (263 nm) harmonic of a femtosecond fibre laser was initiated from the surface of an Ag film deposited on the substrate surface. Photoelectron source localisation on the photocathode surface was provided by sputtering the Cu{sub 2}O copper oxide film on its surface, which significantly (about 50 times) reduced the photoemission efficiency, and by subsequent removal of the copper oxide layer in the photoemission spot with a diameter of ∼15 μm by means of focused second-harmonic radiation of a femtosecond fibre laser. In conducting research on the photocathode surface, a grid of photoemission spots was formed, which greatly facilitated the laser beam alignment with the photoemission spot. A decrease in the noises of ultrafast transmission electron microscope, associated with spatial fluctuations of the laser beam initiating pulsed photoelectron emission from the microscope photocathode when using a localised electron source on the basis of a structure of thin Cu{sub 2}O and Ag films, was experimentally demonstrated. (paper)
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Accelerating structural dynamics simulations with localised phenomena through matrix compression and projection‐based model order reduction
In this work, a novel approach is introduced for accelerating the solution of structural dynamics problems in the presence of localised phenomena, such as cracks. For this category of problems, conventional projection-based Model Order Reduction (MOR) methods are either limited with respect to the range of system configurations that can be represented or require frequent solutions of the Full Order Model (FOM) to update the low-dimensional spaces, in which solutions are represented. In the proposed approach, low-dimensional spaces, constructed for the healthy structure, are enriched with appropriately selected columns of the flexibility matrix of the system. It can be shown that these spaces contain the solution to the original problem for the static case, while their dimension is much smaller. In order to allow their online construction for arbitrary localised features, the full flexibility matrix of the system should be available. To this end, a hierarchical representation is used for the matrices involved, allowing to compute the flexibility matrix efficiently and with reduced memory requirements. The resulting method offers significant speedups, without sacrificing the flexibility and accuracy of the full order model. The performance and limitations of the approach are studied through a series of examples in structural dynamics.
fracture mechanics↗
Spin-current-mediated rapid magnon localisation and coalescence after ultrafast optical pumping of ferrimagnetic alloys
Sub-picosecond magnetisation manipulation via femtosecond optical pumping has attracted wide attention ever since its original discovery in 1996. Furthermore, the spatial evolution of the magnetisation is not yet well understood, in part due to the difficulty in experimentally probing such rapid dynamics. Here, we find evidence of rapid magnetic order recovery in materials with perpendicular magnetic anisotropy via nonlinear magnon processes. We identify both localisation and coalescence regimes, whereby localised magnetic textures nucleate and subsequently evolve in accordance with a power law formalism. Coalescence is observed for optical excitations both above and below the switching threshold. Simulations indicate that the ultrafast generation of noncollinear magnetisation via optical pumping establishes exchange-mediated spin currents with an equivalent 100% spin polarised charge current density of 108 A/cm 2 . Such large spin currents precipitate rapid recovery of magnetic order after optical pumping. These processes suggest an ultrafast optical route for the stabilization of desired meta-stable states, e.g., isolated skyrmions.
36 MATERIALS SCIENCE↗
Monitoring of chlorin-based photosensitiser localisation with dual-wavelength fluorescence imaging: numerical simulations
An approach to the estimation of chlorin-based photosensitiser localisation with dual-wavelength fluorescence imaging after topical application or intravenous injection is developed based on numerical simulations. Fluorescence imaging, which is commonly used for the monitoring of photosensitiser distribution within tissue, does not allow for its depth-resolved imaging. Chlorin-based photosensitisers feature two peaks in their absorption spectra corresponding to 402 and 662 nm, which allows for fluorescence excitation at two wavelengths with significantly different light penetration depths into biotissues. The ratio of fluorescence signals detected upon irradiation at different excitation wavelengths is shown to provide the information about photosensitiser localisation. The cases of exponential in-depth decay of the photosensitiser concentration and uniform photosensitiser distribution within the layer at a certain depth within the medium are analysed. These cases simulate topical application of photosensitiser and its intravenous injection and further accumulation in tumour, respectively. (paper)
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Quantifying and Visualizing Uncertainty for Source Localisation in Electrocardiographic Imaging
Electrocardiographic imaging (ECGI) presents a clinical opportunity to noninvasively understand the sources of arrhythmias for individual patients. To help increase the effectiveness of ECGI, we provide new ways to visualise associated measurement and modelling errors. Here, we study source localisation uncertainty in two steps: First, we perform Monte Carlo simulations of a simple inverse ECGI source localisation model with error sampling to understand the variations in ECGI solutions. Second, we present multiple visualisation techniques, including confidence maps, level-sets, and topology-based visualisations, to better understand uncertainty in source localization. Our approach offers a new way to study uncertainty in the ECGI pipeline.
47 OTHER INSTRUMENTATION↗
Spin-current-mediated rapid magnon localisation and coalescence after ultrafast optical pumping of ferrimagnetic alloys
We identify both localisation and coalescence regimes, whereby localised magnetic textures nucleate and subsequently evolve in accordance with a power law formalism. Coalescence is observed for optical excitations both above and below the switching threshold. Simulations indicate that the ultrafast generation of noncollinear magnetisation via optical pumping establishes exchange-mediated spin currents with an equivalent 100% spin polarised charge current density of 108 A/cm2. Such large spin currents precipitate rapid recovery of magnetic order after optical pumping. These processes suggest an ultrafast optical route for the stabilization of desired meta-stable states, e.g., isolated skyrmions.
14 SOLAR ENERGY↗
Experimental conditions to suppress edge localised modes by magnetic perturbations in the ASDEX Upgrade tokamak
For this, access conditions for full suppression of Edge Localised Modes (ELMs) by Magnetic Perturbations (MP) in low density high confinement mode (H-mode) plasmas are studied in the ASDEX Upgrade tokamak. The main empirical requirements for full ELM suppression in our experiments are: 1. The poloidal spectrum of the MP must be aligned for best plasma response from weakly stable kink-modes, which amplify the perturbation, 2. The plasma edge density must be below a critical value, 3.3 × 10 19 m -3 . The edge collisionality is in the range v $*\atop{i}$ = 0.15 - 0.42 (ions) and v $*\atop{e}$ = 0.15 - 0.25 (electrons). However, our data does not show that the edge collisionality is the critical parameter that governs access to ELM suppression. 3. The pedestal pressure must be kept sufficiently low to avoid destabilisation of small ELMs. This requirement implies a systematic reduction of pedestal pressure of typically 30% compared to unmitigated ELMy H-mode in otherwise similar plasmas. 4. The edge safety factor q 95 lies within a certain window. Within the range probed so far, q 95 = 3.5 - 4.2, one such window, q 95 = 3.57-3.95 has been identified. Within the range of plasma rotation encountered so far, no apparent threshold of plasma rotation for ELM suppression is found. This includes cases with large cross field electron flow in the entire pedestal region.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Localisation in a Growth Model with Interaction
This paper concerns the long term behaviour of a growth model describing a random sequential allocation of particles on a finite cycle graph. The model can be regarded as a reinforced urn model with graph-based interaction. It is motivated by cooperative sequential adsorption, where adsorption rates at a site depend on the configuration of existing particles in the neighbourhood of that site. Our main result is that, with probability one, the growth process will eventually localise either at a single site, or at a pair of neighbouring sites.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Localised instability of titanium during its erosion-corrosion in simulated acidic hydrometallurgical slurries
Electrochemical techniques were used to investigate the erosion-corrosion of titanium in simulated acidic mineral leaching slurries. Erosion-corrosion of titanium was caused by solid particle impingement. Electrochemical noise revealed that solid particle impacts resulted in localised fracture of the passive film, and erosion-corrosion of titanium proceeded in the form of current transients. As conditions become more abrasive, erosion-corrosion is an increasing threat to titanium equipment exposed to acidic slurries.
36 MATERIALS SCIENCE↗
Deformation localisation in ion-irradiated Fe and Fe10Cr
Determining the mechanisms for irradiation-induced ductility loss is crucial for the design of reactor structural components. Here, the deformation characteristics around nanoindents in Fe and Fe10Cr irradiated with Fe ions to ~1 displacement-per-atom at 313 K are non-destructively studied. Slip steps surrounding the nanoindents indicate that deformation is localised in the irradiated materials. Lattice rotation and strain fields near the indent site show over 87% confinement of plasticity in the irradiated material. Cr has little effect on the irradiation-induced changes in pile-up topography and deformation fields, suggesting it has limited impact on retaining strain hardening capacity and reducing irradiation-induced embrittlement.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Characterising the polymorphic phase transformation at a localised point on a Cu6Sn5 grain
Highlights: • A single-targeted Cu{sub 6}Sn{sub 5} grain adjacent to Sn-rich sites and Cu{sub 3}Sn was investigated using HVTEM. • Phase transformation from hexagonal to monoclinic in a single-targeted Cu{sub 6}Sn{sub 5} grains. • A time-temperature transformation (TTT) diagram was constructed using the HVTEM results. - Abstract: Cu{sub 6}Sn{sub 5} is an important intermetallic for electric interconnects and anode material of Li-ion batteries, with a polymorphic transformation from hexagonal eta-Cu{sub 6}Sn{sub 5} at temperatures higher than 186 °C to monoclinic eta′-Cu{sub 6}Sn{sub 5} at lower temperatures. The polymorphic transformation of Cu{sub 6}Sn{sub 5} has the potential to generate internal stresses in soldered joints during both the soldering process and subsequent device operation involving thermal cycling. Here we developed a systematic method to characterise the polymorphic transformations at localised points in a single grain of Cu{sub 6}Sn{sub 5} that is in intimate contact with adjacent Sn rich and Cu{sub 3}Sn phases to establish a time–temperature transformation (TTT) diagram of the eta to eta′-Cu{sub 6}Sn{sub 5} transformation. The method involves in situ temperature-controlled high-voltage transmission electron microscopy (HVTEM) of a single-targeted Cu{sub 6}Sn{sub 5} grain with observation of diffraction patterns during multiple heating and cooling experiments on a 0.5 μm thick sample made by focused ion beam milling (FIB). The results are compared to previously reported powder X-ray diffraction data. It is concluded that there is good agreement between both techniques and the transformations observed in the powder are representative of those in individual grains present in polycrystalline structures. Based on the newly developed TTT, it was established that the high-temperature eta-Cu{sub 6}Sn{sub 5} could be stablised down to room temperature if the cooling rate exceeded 20 °C min{sup −1}.
36 MATERIALS SCIENCE↗
Pedestal origin and extrapolation of high-density small edge-localised-modes peak parallel energy fluence in ITER and SPARC
Experimental analysis and simulations with the BOUT++ code show that small edge-localised modes (ELMs) in reactor-relevant high-density regimes originate in a region close to the separatrix and only marginally perturb the pedestal structure. The measured divertor peak parallel energy fluence (ε ∥,peak ) for a database of small ELM scenarios in DIII-D and ASDEX Upgrade can be reproduced, within 40 % accuracy on average, if an ad hoc modification of the Eich peak parallel ELM energy fluence model is applied to account for the small ELM pedestal birth location. This allows for first-order extrapolation of small-ELM divertor ε ∥,peak to ITER and SPARC, resulting in values that satisfy the nominal melting threshold of tungsten monoblocks of 12 MJ m −2 . The findings reported in this study, both via modelling and direct measurements, constitute a step forward in assessing small ELMs in high edge-collisionality scenarios as a viable plasma regime for the operation of next-generation fusion machines.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗