Spatial Resolution Measurements Research Articles

Spatial conflict resolution in marine spatial plans and permitting procedures for offshore wind energy: an analysis of measures adopted in Denmark, England and the Netherlands

As activities in the North Sea are steadily increasing in both size and number, spatial conflicts are becoming increasingly inevitable. Marine Spatial Planning is widely adopted as an area-based planning approach to manage competing claims for maritime space, but spatial conflicts are also managed through permitting procedures for maritime activities. To explore how Denmark, England and the Netherlands resolve, minimize or mitigate spatial conflicts, this paper identifies what conflict resolution measures are adopted in marine spatial plans and permitting procedures, and analyzes how national institutional capacities shape their deployment. Collected data includes marine spatial plans and permitting documents as well as interviews with involved policy- and decision-makers. The findings demonstrate a common set of guiding principles for conflict resolution in their marine spatial plans across countries, including spatial reservation, multi- or co-use, ecosystem-based planning, and financial compensation. Within permitting procedures, a wide variety of spatial, physical-technical, logistic, and financial conflict resolution measures are adopted to minimize or mitigate spatial conflicts on project-specific levels. However, large differences exist in the degree to which decision-makers prescribe what conflicts must be addressed in what manner during project development. A lack of ecological and spatial knowledge and fragmented governmental responsibilities hinder decision-makers’ freedom to deviate from established types of conflict resolution measures. Overall, this paper presents valuable insights on how conflicts are addressed across the North Sea region as well as how institutional capacities, and institutional space in particular, shape the adoption of conflict resolution measures.

Spatial Resolution Measurement of Microviscosity Using Length-Regulated Aggregation-Induced Emission Probes.

The measurement of microviscosity gradients across different regions of self-assembled systems is crucial for optimizing their performance in both biological and industrial applications. However, this task has long been challenging due to the spatial barrier within the self-assembled systems, the interference from polarity gradients, and the lack of region-positioned probes. To overcome these challenges, we developed three kinds of length-regulated aggregation-induced emission (AIE) probes for the spatial resolution measurement of microviscosity. These AIE probes with varying alkyl chain lengths showed high sensitivity (0.81) over a viscosity range from 2 to 435 mPa s and unaffected luminescence to environmental polarity, ensuring accurate measurements in diverse environments. Using micelles as a model of self-assembled systems, these AIE probes were able to localize selectively in different regions ranging from the hydrophobic core to the hydrophilic shell and interface. The results indicated that microviscosity was highest in the core and gradually decreased toward the outer regions. Furthermore, these AIE probes were successfully applied for monitoring microviscosity in hydrogels and food thickeners, showing a strong correlation among fluorescence intensity, tensile strength, and thickening effects. These findings underscore the potential of length-regulated AIE probes for evaluating the microviscosity in diverse applications.

Robust interpolation of EEG/MEG sensor time-series via electromagnetic source imaging

Objective.electroencephalography (EEG) and magnetoencephalography (MEG) are widely used non-invasive techniques in clinical and cognitive neuroscience. However, low spatial resolution measurements, partial brain coverage by some sensor arrays, as well as noisy sensors could result in distorted sensor topographies resulting in inaccurate reconstructions of underlying brain dynamics. Solving these problems has been a challenging task. This paper proposes a robust framework based on electromagnetic source imaging for interpolation of unknown or poor quality EEG/MEG measurements.Approach.This framework consists of two steps: (1) estimating brain source activity using a robust inverse algorithm along with the leadfield matrix of available good sensors, and (2) interpolating unknown or poor quality EEG/MEG measurements using the reconstructed brain sources using the leadfield matrices of unknown or poor quality sensors. We evaluate the proposed framework through simulations and several real datasets, comparing its performance to two popular benchmarks-neighborhood interpolation and spherical spline interpolation algorithms.Results.In both simulations and real EEG/MEG measurements, we demonstrate several advantages compared to benchmarks, which are robust to highly correlated brain activity, low signal-to-noise ratio data and accurately estimates cortical dynamics.Significance.These results demonstrate a rigorous platform to enhance the spatial resolution of EEG and MEG, to overcome limitations of partial coverage of EEG/MEG sensor arrays that is particularly relevant to low-channel count optically pumped magnetometer arrays, and to estimate activity in poor/noisy sensors to a certain extent based on the available measurements from other good sensors. Implementation of this framework will enhance the quality of EEG and MEG, thereby expanding the potential applications of these modalities.

Understanding and modeling of gas puff injection for diagnostic purposes.

This article presents an experimental setup capable of providing high spatial and temporal resolution measurements of neutral gas puff injection using a glow discharge to excite the neutral gas and an ultra-high-speed camera to record the emitted light. Using the proposed setup, the shape and propagation velocity of a thermal deuterium gas puff at 1bar have been measured. The cloud has a conical shape and a propagation velocity of vprop = 1870 ± 270m/s. Furthermore, a code has been developed with the aim of studying the relation between the propagation velocity and the initial injection velocity of the gas. The simulations show that an initial injection velocity in the range of vinj ∼ 1650-1950m/s can reproduce a propagation velocity of vprop = 1870 ± 270m/s.

Coupled echosounder and Doppler profiler measurements in the Strait of Gibraltar

Long time series of velocity profiles collected by up-looking acoustic profilers in the westernmost sill of the Strait of Gibraltar show an unexpected pattern in the deepest ∼80 m of the water column, consisting in an appreciable diurnal weakening of the measured horizontal velocity. A harmonic analysis performed on long time series reveals a surprising magnitude of S1 constituent (exactly 1 cpd of frequency) in the horizontal velocity and echo amplitude, which prevails over the rest of diurnal constituents within this depth range, including K1, despite being around 200 times smaller than it in the tide generating potential. High resolution echograms collected by a new instrument recently installed in the mooring line, point at the diel vertical migration of living acoustic scatterers (zooplankton) as the most reasonable cause. It provokes a nightly depletion of scatterers availability near the bottom, which is registered by the instrument as a nighttime weakening of the velocity, as well as an increase of its uncertainty, at the deepest part of the profile. Newly acquired high spatial resolution measurements of the velocity near the seafloor report intense currents which are incompatible with the ones produced by the scatterers scarceness. This result indicates an overall underestimation of the Mediterranean current in previous works of approximately 17% within the depth range of 280–360 m, which in turn translates into an underestimation of previously computed outflow of ∼5%. These new findings make it necessary the re-computation of all the near-20-year long (to date) series of Mediterranean outflow based on the observations collected at this sill of the Strait of Gibraltar.

A compact and mobile stray-field NMR sensor

In this paper, we introduce a compact, single-sided stray field sensor for NMR relaxometry applications. The sensor consists of four main components: the magnet, the RF coil, the spectrometer, and the translation stage. Our proposed magnet, an improved design of the Profile NMR-MOUSE, is designed for low weight, compactness, and magnetic field homogeneity, achieved through various shim strategies using a mixed genetic algorithm. The magnet comprises eight NdFeB blocks, generating a magnetic field of 0.424T within the sensitive region, positioned 12 mm above the magnet surface. For high spatial resolution measurements, we optimized the sensor performance by using a custom-designed rf coil, providing maximum sensitivity, lateral selectivity, and a dead time of less than 20µs. Moreover, we utilized 3D-printed structures to precisely align the sensitive slice within the object, using an experimental approach based on CPMG measurements. The presented setup achieved a spatial resolution of 50µm, with resolution changes proportional to acquisition time. We demonstrate the sensor's versatility and high resolution with measurements on materials such as cosmetics, elastomers, glue, and wood, verifying the good performance of our design, our alignment strategy, and the measuring scheme.

A conceptual model explaining spatial variation in soil nitrous oxide emissions in agricultural fields

Soil emissions of nitrous oxide contribute substantially to global warming from agriculture. Spatiotemporal variation in nitrous oxide emissions within agricultural fields leads to uncertainty in the benefits of climate-smart agricultural practices. Here, we present a conceptual model explaining spatial variation in temporal patterns of soil nitrous oxide emissions developed from high spatial resolution measurements of soil nitrous oxide emissions, gross nitrous oxide fluxes, and soil physicochemical properties in two maize fields in Illinois, USA. In sub-field locations with consistently low nitrous oxide emissions, soil nitrate and dissolved organic carbon constrained nitrous oxide production irrespective of changes in soil moisture. In sub-field locations where high emissions occurred episodically, soil nitrate and dissolved organic carbon availability were higher, and increases in soil moisture stimulated nitrous oxide production. These findings form the ‘cannon model’ which conceptualizes how sub-field scale variation in soil nitrate and dissolved organic carbon determines where increases in soil moisture can trigger high soil nitrous oxide emissions within agricultural fields.

The water vapor distribution profile in dry soil layer during evaporating with high spatial resolution monitored by distributed fibre-optic sensing technology

The dry soil layer (DSL) typically forms on the surface of sandy soils during the evaporation process, with water in the DSL moving solely as vapor. Understanding the DSL thickness and its water vapor distribution is crucial for accurately estimating soil water flux, improving evaporation mechanisms, and enhancing ecological conservation efforts. This study employed distributed fibre-optic sensing (DFOS) technology to achieve high spatial resolution measurements (up to 1 mm) of the water vapor distribution within the DSL. We measured soil water vapor profiles in a sand column subjected to evaporation over 24 days using a 60 cm long relative humidity sensing probe and an optical frequency domain reflection (OFDR) interrogator. We effectively captured the downward migration of the evaporating surface from the sand surface and quantified the inhibitory effect of DSL thickness on evaporation using a logarithmic function. Additionally, we identified a linear distribution of water vapor with depth in the DSL. Our findings offer novel insights into the role of DSL in the hydrological behaviour of unsaturated soils and demonstrate the potential of our approach for investigating dynamic changes in in-situ DSLs, particularly in arid and semi-arid regions.

High Spatial Resolution and Accurate Temperature Profile Measurements in a Nuclear Reactor Core Enabled by Machine Learning

High Spatial Resolution and Accurate Temperature Profile Measurements in a Nuclear Reactor Core Enabled by Machine Learning

Detecting and Imaging of Magnons at Nanoscale with van der Waals Quantum Sensor

AbstractMagnonic devices are extensively studied for energy‐efficient information processing. High spatial resolution and high accuracy measurement is required to characterize the excitation and distribution of magnons. Here, sensing and imaging of magnons in the magnetic insulator (YIG) is realized with negatively charged boron vacancy () spin defects in 2D hexagonal boron nitride (hBN). Thermal magnon noise is studied through spin relaxometry, illustrating the nanometers proximity of the 2D quantum sensor over a large area. The small probe‐sample standoff distance helps to detect weak signals with diffraction‐limited spatial resolution. The uniform out‐of‐plane symmetry axis of is further utilized to study perpendicular magnetic anisotropy (PMA). It effectively extracts the stray field of microwave‐excited magnons from the direct stripline field. The distributions of propagating and localized magnons in different structures are subsequently imaged and analyzed. The work provides the strategy for utilizing the distinctive advantages of the van der Waals quantum sensor in magnetic imaging. The results will promote the development of magnonic devices for diverse applications.

The Method and Experiment of Detecting the Strength of Structural Components Utilizing the Distributed Strain of Sensing Optical Fibers Demodulated by OFDR.

Defects occurring during the welding process of metal structural components directly affect their overall strength, which is crucial to the load-bearing capacity and durability of the components. This signifies the importance of accurate measurement and assessment of weld strength. However, traditional non-destructive testing methods such as ultrasonic and non-contact camera inspection have certain technical limitations. In response to these issues, this paper analyzes the detection principle of weld strength, revealing that weld defects reduce the effective area of the structural bearing section and cause stress concentration around them. Through repeated experimental data analysis of samples, strain distribution data along the one-dimensional direction caused by defects such as slag inclusion and porosity were obtained. Experimental results show that this method can identify defect types in welds, including slag inclusion, porosity, and unevenness, and accurately measure the location and size of defects with a precision of 0.64 mm, achieving qualitative analysis of weld defects. Additionally, by deploying distributed optical fiber sensors (DOFS) at different vertical distances along the weld direction, the propagation law of stress induced by different types of weld defects on samples was thoroughly analyzed. This further validates the advantages of this method in weld strength detection, including high spatial resolution, high sensitivity, and non-destructive measurement.

Retrieval of Aerosol and Surface Properties at High Spatial Resolution: Hybrid Approach and Demonstration Using Sentinel‐5p/TROPOMI and PRISMA

AbstractSatellite remote sensing of aerosol is largely conducted at moderate or coarse spatial resolution around 1–10 km. Nevertheless, at urban areas with high human activity, aerosol can originate from complex emission sources and may also vary strongly in space. Therefore, aerosol characterization at fine spatial resolution is essential for air quality study and assessment of anthropogenic pollution as well as climate effects. However, space‐borne instruments with high spatial resolution are usually limited in swath width or spectral coverage which result in lowering information content required for aerosol and surface retrieval. Based on the Generalized Retrieval of Atmosphere and Surface Properties (GRASP) algorithm, we propose a hybrid approach by combining fine and coarse spatial resolution measurements to retrieve aerosol and surface properties simulataneously at fine spatial resolution. The instruments with coarse spatial resolution and high revisting time can provide advanced aerosol characterization. At the same time, the instruments with fine spatial resolution are sensitive to spatial variability of aerosol nearby sources. In this study, the GRASP/Hybrid approach is demonstrated and tested based on the European Space Agency Sentinel‐5p/TROPOMI together with the Italian Space Agency PRISMA satellite data. Specifically, the detailed aerosol microphysical properties from Sentinel‐5p/TROPOMI 10 km retrievals are used as a priori information for PRISMA to derive aerosol loading and surface properties at 100 meter (m) spatial resolution. The PRISMA 100 m aerosol and surface retrieval based on the developed GRASP/Hybrid approach are evaluated using available ground‐based and satellite measurements, including AERONET, VIIRS/DB aerosol and PRISMA Level 2 surface reflectance products.

Characteristics of the prototype LAMPS TPC for low-energy nuclear collisions at RAON

Characteristics of the prototype LAMPS TPC for low-energy nuclear collisions at RAON

Spatial resolution measurement method for 3D displays from contrast modulation

Augmented Reality 3D head-up displays use a autostereoscopic 3D display as a panel. The 3D optical unit of autostereoscopic 3D displays controls the direction of the light rays in each pixel, allowing the users enjoy 3D world without glasses. However, these 3D optics cause image quality degradation. Deterioration of resolution has a serious impact on 3D image quality. Therefore, it is important to properly measure the 3D resolution according to 3D optics and analyze its impact. In this study, a method for measuring spatial resolution in 3D displays using contrast modulation is proposed. We describe a conventional 2D resolution measurement methods that are standardized. Based on the existing 2D resolution methods, we propose a 3D resolution method. The spatial and frequency signal responses of 3D displays were investigated. The first method is determined by the predominant frequency series. The second method is conducted by contrast modulation. Through experiments with 3D displays, 3D resolution was measured using the proposed method, and the relationship between the parameters and resolution of 3D optics was examined.

Quantifying Impacts of Local Traffic Policies on PM Concentrations Using Low Cost Sensors in Berlin

Urban air pollution remains a challenge in European cities, despite decades of improvement, especially with respect to recent updates to the World Health Organization’s (WHO) air quality guidelines in 2021. At the same time, a new generation of small sensors for air pollution measurement have opened up new avenues for understanding air pollution in cities. In this study, we use Plantower PMS 5003 sensors to measure PM2.5 alongside three local traffic policies implemented in 2020 and 2021. These measures include a new bike-lane and a temporary community space, as well as the creation of a pedestrian zone through the closure of a street to through-traffic. The measurement campaign used the sensors in both mobile and stationary deployments, utilizing their small size and lower cost to increase spatial and temporal resolution measurements. We calibrate the Plantower sensors using Schmitz et al.’s (2021b) methodology and test three different models: multiple linear regression (MLR), gradient-boosting machines (GBM), and support vector machines (SVM). Results show that sensors are useful for measuring PM2.5. We also find no significant effect of any of the local transport policies on local concentrations of PM2.5, despite previous studies of these policies showing reductions in local NO2 concentrations. This indicates that larger-scale policies tackling urban and regional emissions of PM will be needed to improve PM concentrations and meet WHO standards.

Performance Characteristics of the NeuroEXPLORER, a Next-Generation Human Brain PET/CT Imager.

The collaboration of Yale, the University of California, Davis, and United Imaging Healthcare has successfully developed the NeuroEXPLORER, a dedicated human brain PET imager with high spatial resolution, high sensitivity, and a built-in 3-dimensional camera for markerless continuous motion tracking. It has high depth-of-interaction and time-of-flight resolutions, along with a 52.4-cm transverse field of view (FOV) and an extended axial FOV (49.5 cm) to enhance sensitivity. Here, we present the physical characterization, performance evaluation, and first human images of the NeuroEXPLORER. Methods: Measurements of spatial resolution, sensitivity, count rate performance, energy and timing resolution, and image quality were performed adhering to the National Electrical Manufacturers Association (NEMA) NU 2-2018 standard. The system's performance was demonstrated through imaging studies of the Hoffman 3-dimensional brain phantom and the mini-Derenzo phantom. Initial 18F-FDG images from a healthy volunteer are presented. Results: With filtered backprojection reconstruction, the radial and tangential spatial resolutions (full width at half maximum) averaged 1.64, 2.06, and 2.51 mm, with axial resolutions of 2.73, 2.89, and 2.93 mm for radial offsets of 1, 10, and 20 cm, respectively. The average time-of-flight resolution was 236 ps, and the energy resolution was 10.5%. NEMA sensitivities were 46.0 and 47.6 kcps/MBq at the center and 10-cm offset, respectively. A sensitivity of 11.8% was achieved at the FOV center. The peak noise-equivalent count rate was 1.31 Mcps at 58.0 kBq/mL, and the scatter fraction at 5.3 kBq/mL was 36.5%. The maximum count rate error at the peak noise-equivalent count rate was less than 5%. At 3 iterations, the NEMA image-quality contrast recovery coefficients varied from 74.5% (10-mm sphere) to 92.6% (37-mm sphere), and background variability ranged from 3.1% to 1.4% at a contrast of 4.0:1. An example human brain 18F-FDG image exhibited very high resolution, capturing intricate details in the cortex and subcortical structures. Conclusion: The NeuroEXPLORER offers high sensitivity and high spatial resolution. With its long axial length, it also enables high-quality spinal cord imaging and image-derived input functions from the carotid arteries. These performance enhancements will substantially broaden the range of human brain PET paradigms, protocols, and thereby clinical research applications.

Towards integration of LOTOS-EUROS high resolution simulations and heterogenous low-cost sensor observations

Towards integration of LOTOS-EUROS high resolution simulations and heterogenous low-cost sensor observations

Calibration and performance evaluation of an N-type HPGe detector for a collimated and focused PGNAA system by experimental and Monte Carlo methods

Calibration and performance evaluation of an N-type HPGe detector for a collimated and focused PGNAA system by experimental and Monte Carlo methods

The spatial resolution measurements on the small prototype of the Super Charm-Tau Factory drift chamber

The spatial resolution measurements on the small prototype of the Super Charm-Tau Factory drift chamber

Static and moving minimum audible angle: Independent contributions of reverberation and position.

Two measures of auditory spatial resolution, the minimum audible angle and the minimum audible movement angle, have been obtained in a simulated acoustic environment using Ambisonics sound field reproduction. Trajectories were designed to provide no reliable cues for the spatial discrimination task. Larger threshold angles were found in reverberant compared to anechoic conditions, for stimuli on the side compared to the front, and for moving compared to static stimuli. The effect of reverberation appeared to be independent of the position of the sound source (same relative threshold increase) and was independently present for static and moving sound sources.