1401 research outputs found
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Data associated with 'Exogenous mineralization of hard tissues using photo-absorptive minerals and femto-second lasers; the case of dental enamel'
No full textA radical new methodology for the exogenous mineralization of hard tissues is demonstrated in the context of laser-biomaterials interaction. The proposed approach is based on the use of femtosecond pulsed lasers (fs) and Fe3+-doped calcium phosphate minerals (specifically in this work fluorapatite powder containing Fe2O3 nanoparticles (NP)). A layer of the synthetic powder is applied to the surface of eroded bovine enamel and is irradiated with a fs laser (1040 nm wavelength, 1 GHz repetition rate, 150 fs pulse duration and 0.4 W average power). The Fe2O3 NPs absorb the light and may act as thermal antennae, dissipating energy to the vicinal mineral phase. Such a photothermal process triggers the sintering and densification of the surrounding calcium phosphate crystals thereby forming a new, dense layer of typically ̴20 μm in thickness, which is bonded to the underlying surface of the natural enamel. The dispersed iron oxide NPs, ensure the localization of temperature excursion, minimizing collateral thermal damage to the surrounding natural tissue during laser irradiation. Simulated brushing trials (pH cycle and mechanical force) on the synthetic layer show that the sintered material is more acid resistant than the natural mineral of enamel. Furthermore, nano-indentation confirms that the hardness and Young’s modulus of the new layers are significantly more closely matched to enamel than current restorative materials used in clinical dentistry. Although the results presented herein are exemplified in the context of bovine enamel restoration, the methodology may be more widely applicable to human enamel and other hard-tissue regenerative engineering
Data associated with 'Links between climate change mitigation, adaptation and development in land policy and ecosystem restoration projects: lessons from South Africa'
No full textThematic analysis framework: fieldwork notes gathered through semi-structured interviews, focus group discussions and participatory site visits across study sites, South Afric
Dataset associated with "High-performance GaAs/AlAs superlattice electronic devices in oscillators at frequencies 100–320 GHz"
No full textNegative differential resistance devices were fabricated from two epitaxial wafers with very similar GaAs/AlAs super-lattices and evaluated in resonant-cap full-height waveguide cavities. These devices yielded output powers in the fundamental mode between 105 GHz and 175 GHz, with 14 mW generated at 127.1 GHz and 9.2 mW at 133.2 GHz. The output power of 4.2 mW recorded at 145.3 GHz constitutes a 50-fold improvement over previous results in the fundamental mode. The highest confirmed fundamental-mode oscillation frequency was 175.1 GHz. In a second-harmonic mode, the best devices yielded 0.92 mW at 249.6 GHz, 0.7 mW at 253.4 GHz, 0.61 mW at 272.0 GHz, and 0.54 mW at 280.7 GHz. These powers exceed those extracted previously from higher harmonic modes by orders of magnitude. The power of 0.92 mW constitutes an improvement by 77% around 250 GHz. The second-harmonic frequency of 317.4 GHz is the highest to date for superlattice electronic devices and is an increase by 25% over previous results
Dataset for "Dynamic Measurement of Low Contact Angles by Optical Microscopy"
No full textPrecise measurement of contact angles is an important challenge in surface science, in the design and characterisation of materials and in many crystallisation experiments. Here we present the dataset for a novel technique for measuring the contact angles of droplets between about 2° and 30°, with lowest experimental uncertainty at the lower end of this range, typically ±0.1°. The lensing effect of a droplet interface produces the appearance of bright circles in low-aperture light, whose diameter is related to the contact angle. The technique requires no specialised equipment beyond an ordinary optical microscope, and may be used to study the dynamic evolution of the contact angle in-situ during an experiment
Salt enhanced solvent relaxation during rapid spin-lattice NMR data set
No full textExperimental data: Particle size analysis with and without electrotlye, surface charge, NMR silica (ludox) calibration and relaxation rate data for titanium didoxide, silica and calcite with and without electrolyte. BET surface area isothermal data and pore size distributions for titanium didoxide, silica and calcite
Climate model data presented in 'Climatic effect of Antarctic meltwater overwhelmed by concurrent Northern hemispheric melt': hiS_leads_loN
No full textOutput from a set of 9 global climate simulations for four transient scenarios of ice sheet meltwater contributions to the Meltwater Pulse 1a rapid sea level rise ~14.5 ka. The simulations were run with the HadCM3 general circulation model at the University of Leeds. They correspond to a 'background' meltwater flux (which comprises the first 525 years of all four meltwater pulse scenarios: teqjb) and the four transient meltwater pulse scenarios ('hiN_loS': teqjc + teqjg; 'hiS_loN': teqjd + teqjh; 'hiN_leads_loS': teqje + teqji; 'hiS_leads_loN': teqjf + teqjj), where the first simulation has a transient meltwater forcing for Meltwater Pulse 1a (teqjc, teqjd, teqje and teqjf, respectively), and the second simulation is a continuation returning to the 'background' meltwater flux (teqjg, teqjh, teqji and teqjj, respectively). All of these scenarios are fully described in the accompanying paper (Ivanovic et al., 2018, Geophysical Research Letters, doi: 10.1029/2018GL077623). The data is provided in NETCDF3 format within zipped directories corresponding to the meltwater scenarios. It consists of the freshwater forcing files (i.e. model input) and model output for each simulation. Model output is provided as time-series for a range of ocean, atmosphere and vegetation data. See the accompanying README.txt for a list of supplied output variables as well as more information on the directory structure for the supplied data
Data associated with 'The Influence of Calcium Sulfate Bone Void Filler on the Third Body Damage and Polyethylene Wear of Total Knee Replacements'
No full textThe dataset contains material to supplement the paper “The Influence of Calcium Sulfate Bone Void Filler on the Third Body Damage and Polyethylene Wear of Total Knee Replacements” including: wear rates and wear volumes of UHMWPE tibial components and surface roughness analysis of cobalt chrome femoral components following both third body damage simulation and experimental wear simulation using a contacting Form Talysurf
Dataset Associated with 'Deconvolution of Rashba and Dresselhaus spin-orbit coupling by crystal axis dependent measurements of coupled InAs/GaSb quantum wells'
No full textThe Dresselhaus spin-orbit interaction is expected to perturb the quantum spin Hall phase predicted to arise within InAs/GaSb coupled quantum wells. To gain a greater understanding of this interaction, the spin-orbit coupling in two InAs/GaSb coupled quantum well samples, grown along the [001] axis, was investigated along three different in-plane crystallographic axes. By measuring the crystallographic axis dependence of the Dresselhaus spin orbit coupling, we can deconvolute this coupling from the spin splitting arising from axis-invariant Rashba spin-orbit coupling. We find that the Dresselhaus parameter is robust against an external gate bias and small changes in growth conditions, with an associated Dresselhaus parameter of (0.20±0.08)×10^-11 eVm being measured across all samples and top gate bias conditions. In addition, we show that the asymmetries associated with the coupled quantum well structure, leading to Rashba spin-orbit coupling, are likely to play a dominant role in determining the spin-orbit interaction experienced by a quantum spin Hall state as the system is tuned towards charge neutrality
Dataset associated with Creation and topological charge switching of defect loops on a long fibre in the nematic liquid crystal dataset
No full textWe demonstrate new type of topological defects on a homeotropic fibre aligned perpendicular to the nematic director in a planar nematic cell. Contrary to expectations we can create defect loops which are encircling the fibre along its short axis and are strongly tilted with respect to the fibre. Such loops are always accompanied by two topological solitons, which emanate from the loop and propagate to the left and right hand side of the fibre. Unlike previously reported closed loops of either positive and negative charge, encircling the fibre parallel to the nematic director, these loops can carry either positive or negative charge, or can be charge neutral and very stable. We show how to switch the charge of individual loops from positive to neutral and negative charge by adding unit monopoles of appropriate topological charge. We demonstrate new type of interaction of dipolar colloids with these new topological entities on a fibre
Data associated with ‘Multi-modal millimeter-wave sensors for plastic polymer material characterization’
No full textThis paper presents, for the first time, a multimodal sensor for characterizing relative permittivity of plastic polymers by integrating in a single sensor (1) frequency-reconfigurable resonance technique at 98 and 100 GHz, and (2) 80-100-GHz broadband modified transmission-line technique. The sensor is designed based on a custom-made WR-10 waveguide featuring dual rectangular Complementary Split-Ring Resonators (CSRRs). By loading the CSRRs with a Material-Under-Test (MUT), the reflected and transmitted electromagnetic waves propagating inside the waveguide are changed depending on the dielectric properties of the material. Various plastic polymer materials, e.g. Polytetrafluoroethylene (PTFE), Polymethylmethacrylate (PMMA) and High-Density Polyethylene (HDPE), are characterized. The sensor in this paper offers various key advantages over any state-of-the-art material characterization techniques at millimeter-wave frequencies, e.g. multiple characterization techniques integrated in a single device, miniaturization, much higher tolerance to changes in the measurement environment, ease of design and fabrication, and better cost effectiveness