Reference Surface Research Articles

Inherent scatter in pool boiling critical heat flux on reference surfaces

Evaluating boiling heat transfer enhancement depends on reliable reference values in the form of boiling curves and critical heat flux (CHF) values. Typically, the evaluation is performed in pool boiling conditions with water at atmospheric pressure. Literature includes a wide scatter in reference values, prompting this study to comprehensively evaluate boiling performance and CHF on reference surfaces to investigate the scatter's origin and set a definitive reference value. The study recorded 125 boiling curves and CHF values on nominally identical bare copper surfaces, establishing an average boiling curve and mean CHF value. Despite consistent experimental conditions, the recorded CHF values displayed significant variability with a mean CHF of 1112 ± 102 kW m−2 and a scatter from 902 kW m−2 (−19 % of average CHF) to 1339 kW m−2 (+25 % of average CHF). Using Rohsenow's correlation on the average boiling curve, a Csf factor of 0.0151 was obtained. The acquired CHF data is proposed to serve as a foundational benchmark for future research in enhancing pool boiling heat transfer.

Variability in oceanographic conditions affecting Mesophotic Ecosystems along the South Eastern Pacific: Latitudinal trends and potential for climate refugia

Oceans have been changing at the fastest pace since the beginning of the Holocene. The South Eastern Pacific (SEP), including the Humboldt Upwelling Ecosystem (HUE) is subject to changes in upwelling winds, temperature, El Niño, and the ever-increasing local anthropogenic stressors, all of which have been documented for surface coastal waters where in-situ and remote observations are readily available. Temporal and spatial changes in the adjacent deeper waters where diverse Mesophotic Ecosystems are found have been scarcely documented. These marine ecosystems have been the focus of ecological studies for less than two decades. Here we provide an overview of the thermal variability at mesophotic depths and assess their potential as climatic refugia along all SEP ecoregions. We analyzed a time series of temperature and salinity from a 19 yr reanalysis based on remote and in-situ observations (CTD, ARGO, XBTs, moorings) to quantify variability in the Tropical (0–5°S), Northern Warm Temperate (5–30°S); Southern Warm Temperate (30–39.5°S) and Magellanic subregions (39.5–45°S), at two mesophotic depth strata (50 and 100 m), and a reference surface (5 m) depth. We assessed variability in the seasonal, interannual (El Niño) and ‘long-term’ (ca. 20 yr) scales, and the relationship with wind velocities. The thermal depth gradient between surface and mesophotic depths did not change smoothly with latitude but peaked within the northern portion of the warm temperate subregion, decreasing towards lower and higher latitudes. Seasonal variation in temperature was also largest in the north and south temperate subregions and minimal in the Magellanic subregion. Depth dampening of seasonal temperature variation was also strengthened at intermediate latitudes and much reduced in the tropics, where seasonal variation at mesophotic depths was similar to that at the surface. The strong interannual El Niño events were identified at all depths in tropical and temperate subregions, with stronger standardized effects at mesophotic layers than at the surface. Long-term (ca. two decades) temperature trends were significant and changed direction from warming to cooling along the SEP but were generally patchier at mesophotic layers. Spatial temperature gradients have remained relatively stable over the past two decades and were stronger at the surface than at mesophotic depths, and stronger within the tropics than in all other subregions. Surprisingly, the velocity of climate change was patchier and generally faster at mesophotic layers than at the surface. We conclude that, judging solely by physical environmental conditions, mesophotic ecosystems may be used by species with very different temperature affinities in temperate subregions, while in the tropics, more overlap in temperature affinities of component species may be found. Importantly, while the seasonal amplitude is reduced at mesophotic depth in most subregions, except the tropics, interannual disturbances affect mesophotic depths at least as strongly as they do surface waters and climate change velocities are faster at mesophotic depths than at surface. Thus, these ecosystems are not sheltered from inter-annual and longer-term forcing and their biotas might be more vulnerable to climate change than shallow coastal ecosystems.

Nieselektywne powierzchnie referencyjne w teledetekcji hiperspektralnej w zakresie dalekiej podczerwieni

This article focuses on the construction of reference surfaces with the desired spectral characteristics similar to a gray body. Using wooden plywood with a rough surface and coatings of various emissivity values, surfaces with non-selective spectral properties were created. The consistency of laboratory measurement results using a reflectance spectrometer with data obtained from a hyperspectral camera was confirmed. By utilizing multiple reference surfaces with precisely known emissivity characteristics, it will be possible to accurately determine the radiation components of the measured scene’s surroundings. Although the technology of these surfaces still requires improvement, their usefulness in remote sensing measurements is undeniable. Additionally, differences in response to solar radiation between various reference surfaces provide significant information that can be used in remote sensing and material identification. Incorporating the heating dynamics of the studied objects’ surfaces is crucial for accurate measurement modeling.

Connecting the Brazilian Vertical System to the International Height Reference Frame by estimating the vertical datum parameters

One of the challenges in the unification of the global vertical datum is to determine the vertical offset between the local vertical datum and the global vertical datum. Since 2015, the scientific community has been working on the unification of the global vertical datum, following the publication of the resolution for the definition and realization of an International Height Reference System. This paper aims to estimate the vertical offset in Brazil (Imbituba and Santana Data) by combining a regional gravity field model, using the Geodetic Boundary Value Problem approach applying the Remove-Compute-Restore procedure, and GNSS/leveling data. In the Imbituba vertical datum 1271 stations were used and 66 stations were connected to the Santana tide gauge. The results showed that the geopotential value of Imbituba was 62,636,849.87 ± 0.224 m2s-2, and the vertical offset concerning the reference surface (W0) was 0.358 ± 0.023 m. In Santana, the geopotential value was 62,636,836.88 ± 4.108 m2s-2, and the vertical offset was 1.689 ± 0.420 m. The offset between Imbituba and Santana was computed once the physical connection between Brazil's two local vertical data is a challenge. The estimated value was 1.331 ± 0.421 m. This means the Santana vertical datum is 1.331 m higher than the Imbituba vertical datum.

Determination of the Geoid Heights of Awka and Environ from the Satellite Altimetry data using Broadview RADAR Altimeter Toolbox (BRAT) and Sentinel-3 Missions

Satellite altimetry has revolutionized our ability to measure Earth's surface with unprecedented accuracy, offering invaluable insights into various geophysical phenomena. This study presents the determination of geoid heights (Ns) of Awka and Environ utilizing the Broadview RADAR Altimeter Toolbox (BRAT) in conjunction with data from the Sentinel-3 missions. The geoid, a surface of constant gravitational potential representing mean sea level, is a fundamental reference surface for geodetic measurements and understanding Earth's gravity field. The methodology involves processing raw altimetry data acquired by the Sentinel-3 missions using BRAT, followed by precise corrections for various factors affecting the altimeter measurements, such as atmospheric delays, sea state bias, and orbit errors. Subsequently, the derived SSH data are combined with precise geoid models to compute the geoid heights at different spatial resolutions. The results demonstrate the effectiveness of the approach in determining geoid height (N) with high precision and spatial resolution, offering valuable contributions to geodetic research and applications. The utilization of Sentinel-3 data combined with BRAT facilitates robust and accurate geoid determination, which is essential for a wide range of geospatial applications, including oceanography, geophysics, and climate studies. The integration of BRAT and Sentinel-3 missions offers a powerful tool for geodetic research and applications, contributing to our understanding of Earth's dynamic processes and improving the accuracy of geospatial measurements.

Measuring uncertainty of hydraulic generator efficiency by calorimetric method

Abstract Calorimetric method is generally performed on determination of hydraulic generator efficiency. Generator losses could be evaluated by measuring the heat taken by cooling medium or dissipated from a reference surface. To satisfy the requirements of measuring uncertainty in IEC 60034, special attention must be paid. An estimation method is proposed and performed on a hydraulic generator for calorimetric test. Estimation result shows that discharge of cooling water must be reduced to a rather low value to ensure the measuring uncertainty of calorimetry within 3%. Also, a lower cooling discharge can bring higher temperature rise then reduce the measuring uncertainty caused by temperature measurement. Furthermore, to reduce the measuring uncertainty of cooling discharge, flowmeters must be installed correctly.

Application of Geoid and Mean Dynamic Topography Models as an Alternative to the Mean Sea Level Approach in Determining Vertical Datum (Case Study: Java Island and Surrounding)

Abstract Indonesia’s archipelagic territory provides constraints for determining a seamless vertical datum throughout the region. The main constraint is how to connect the vertical datum between islands separated by sea. To define the physical height system of land areas, it usually refers to the Mean Sea Level (MSL), which has different values in each area, and the ideal MSL information is not yet available throughout regions with a minimum data duration of one cycle of 18.6 years. To overcome this constraint, in this research, another alternative method is used: applying a vertical datum that refers to a physical geoid reference surface, namely Mean Dynamic Topography (MDT) using Altimetry satellite data. The study area is Java Island and its surroundings, using vertical information from Geodetic Control Point stations, which also function as Tidal stations in the Indonesian Geospatial Reference System network. The range of MDT deviation values obtained from the Satellite Altimetry with Geodetic Ground Control data is ± 2 meters, which is a good value for coastal areas facing the open sea. This shows that the application of the geoid and MDT models can be used as an alternative, seamless MSL approach in the Java Island region and its surroundings.

Estimating differential penetration of green (532 nm) laser light over sea ice with NASA's Airborne Topographic Mapper: observations and models

Abstract. Differential penetration of green laser light into snow and ice has long been considered a possible cause of range and thus elevation bias in laser altimeters. Over snow, ice, and water, green photons can penetrate the surface and experience multiple scattering events in the subsurface volume before being scattered back to the surface and subsequently the instrument's detector, therefore biasing the range of the measurement. Newly formed sea ice adjacent to open-water leads provides an opportunity to identify differential penetration without the need for an absolute reference surface or dual-color lidar data. We use co-located, coincident high-resolution natural-color imagery and airborne lidar data to identify surface and ice types and evaluate elevation differences between those surfaces. The lidar data reveals that apparent elevations of thin ice and finger-rafted thin ice can be several tens of centimeters below the water surface of surrounding leads, but not over dry snow. These lower elevations coincide with broadening of the laser pulse, suggesting that subsurface volume scattering is causing the pulse broadening and elevation shift. To complement our analysis of pulse shapes and help interpret the physical mechanism behind the observed elevation biases, we match the waveform shapes with a model of scattering of light in snow and ice that predicts the shape of lidar waveforms reflecting from snow and ice surfaces based on the shape of the transmitted pulse, the surface roughness, and the optical scattering properties of the medium. We parameterize the scattering in our model based on the scattering length Lscat, the mean distance a photon travels between isotropic scattering events. The largest scattering lengths are found for thin ice that exhibits the largest negative elevation biases, where scattering lengths of several centimeters allow photons to build up considerable range biases over multiple scattering events, indicating that biased elevations exist in lower-level Airborne Topographic Mapper (ATM) data products. Preliminary analysis of ICESat-2 ATL10 data shows that a similar relationship between subsurface elevations (restored negative freeboard) and “pulse width” is present in ICESat-2 data over sea ice, suggesting that biased elevations caused by differential penetration likely also exist in lower-level ICESat-2 data products. The spatial correlation of observed differential penetration in ATM data with surface and ice type suggests that elevation biases could also have a seasonal component, increasing the challenge of applying a simple bias correction.

Application of laser treatment technology for boiling heat transfer augmentation

Abstract Boiling heat transfer can be enhanced when the heater’s surface morphology is altered. The paper discusses the use of the laser beam to produce efficient heat exchangers. Two types of samples were investigated with distilled water and ethyl alcohol as boiling agents. The specimens differed with the height of the microfins: 0.19 mm and 0.89 mm. It was observed that both of them enhanced boiling heat transfer in comparison to the smooth reference surface. However, the sample with higher microfins performed better, especially in the region of low temperature differences, where the heat flux was about three times higher than in the case of the smaller microfins. The comparison of the experimental data with selected models of boiling heat transfer revealed significant differences with regard to the heat flux. The laser-made samples dissipated larger heat fluxes than it could be anticipated according to the models. It might be linked with high surface roughness of the area between the microfins, generated as a result of the laser beam interaction with the surface.

Pool boiling performance for GaldenR HT 55 subject to smooth, pin fin, and sintered pin fin heat sink

The dielectric fluid of GaldenR HT 55 (Perfluoropolyether) is regarded as a potential candidate for two-phase immersion cooling since its boiling point at 1 atm is 55 °C which is quite suitable for electronics cooling. The fluid is of special interest since the main vender of dielectric fluid will no longer produce FGAS after 2024. However, very rare nucleate boiling performance data for HT55 were reported in the literature. The objective of this study aims to provide nucleate boiling performance data for various heat sinks applicable for nucleate boiling. The test samples include a smooth reference surface (#1), 2 pin fins (the pin diameters are 1 mm (#2) and 2 mm (#3), and 3 pin fin with various sintered coatings (powder size: 150–200 μm (#4), 200–250 μm (#5), and 250–350 μm (#6)). Heat flux spans from 80 to 600 kW/m2. HTC for small pin fin (#2) is marginally higher than that of smooth surface, and large pin fin (#3) shows about 40 % enhancement compared to smooth surface at 140 kW/m2. HTCs for sintered pin fins are much higher than those of pin fin or smooth surface with approximately 90–95 % enhancement relative to the smooth surface at low heat flux. The visual observations indicate that sample #6 yields the largest bubble departure diameter and departure frequency. Yet bubble generations are especially pronounced on top of the pin fin. The CHF of the tested surfaces are following the sequence: #5 > #6 > #4 > #3 > #2 > #1. The sample #5 contains a CHF over 600 kW/m2 which is about four times higher than that of the smooth surface.

Ocean Satellite Data Fusion for High-Resolution Surface Current Maps

Real-time reconstruction of ocean surface currents is a challenge due to the complex, non-linear dynamics of the ocean, the small number of in situ measurements, and the spatio-temporal heterogeneity of satellite altimetry observations. To address this challenge, we introduce HIRES-CURRENTS-Net, an operational real-time convolutional neural network (CNN) model for daily ocean current reconstruction. This study focuses on the Mediterranean Sea, a region where operational models have great difficulty predicting surface currents. Notably, our model showcases higher accuracy compared to commonly used alternative methods. HIRES-CURRENTS-Net integrates high-resolution measurements from the infrared or visible spectrum—high resolution Sea Surface Temperature (SST) or chlorophyll (CHL) images—in addition to the low-resolution Sea Surface Height (SSH) maps derived from satellite altimeters. In the first stage, we apply a transfer learning method which uses a high-resolution numerical model to pre-train our CNN model on simulated SSH and SST data with synthetic clouds. The observation of System Simulation Experiments (OSSEs) offers us a sufficient training dataset with reference surface currents at very high resolution, and a model trained on this data can then be applied to real data. In the second stage, to enhance the real-time operational performance of our model over previous methods, we fine-tune the CNN model on real satellite data using a novel pseudo-labeling strategy. We validate HIRES-CURRENTS-Net on real data from drifters and demonstrate that our data-driven approach proves effective for real-time sea surface current reconstruction with potential operational applications such as ship routing.

Multisource elevations strategy obtaining robust seed points and reference surfaces for ground points extraction in complex terrain area

The appearance of unmanned aerial vehicle photogrammetry and airborne lidar makes it possible to obtain measurement data for complex terrains such as gullies and mountainous regions. However, extracting ground points from these abundant and massive measurement datasets is challenging. In traditional extractions, their essence is to determine the surfaces that can describe the terrain from the seed points in the grid and use them as the basis for separating non-ground points. For effective extraction, this study proposes a multisource elevations strategy (MES) obtaining robust seed points and reference surfaces. First, two-level extended grids were constructed as the basic units. Then, to select more robust values between measurement and interpolation elevations, an elevation-determination rule was established for seed points. After, based fitting and interpolation elevations of grid nodes, the correction range is determined and the elevation is corrected for reference surfaces. In two representative complex terrain areas, when non-ground points were marked as seed points, the MES effectively reduced the phenomenon of seed points moving away from the ground. Reference surfaces can also accurately represent the global change trend and local elevation of the ground in areas where the terrain changes rapidly. This strategy provides a new thinking for ground point extraction from point cloud.

Shot Peening Effect on Sliding Wear in 0.9% NaCl of Additively Manufactured 17-4PH Steel.

The growing demand for modern steels showing corrosion and tribological resistance has led to their increased use in the production of medical devices. This study analyzed the effect of shot peening on wear resistance in 0.9% NaCl solution of 17-4PH steel produced by direct laser metal sintering (DMLS) technology. The study's novelty relies on revealing the effect of shot peening (SP) surface treatment on the wet sliding wear resistance of 17-4PH steel produced with DMLS. Moreover, in the context of 17-4PH steel application for medical devices, the 0.9% NaCl tribological environment were selected, and SP processes were conducted using steel CrNi shot and ceramic (ZrO2) beads. The up-to-date scientific literature has not identified these gaps in the research. DMLS technology makes it possible to obtain products with complex architectures, but it also faces various challenges, including imperfections in the surface layer of products due to the use of 3D printing technology itself. The chemical and phase composition of the materials obtained, Vickers hardness, surface roughness, and microscopic and SEM imaging were investigated. Tribological tests were carried out using the ball-on-disc method, and the surfaces that showed traces of abrasion to identify wear mechanisms were subjected to SEM analysis. The XRD phase analysis indicates that austenite and martensite were found in the post-production state, while a higher martensitic phase content was found in peened samples due to phase transformations. The surface hardness of the peened samples increased by more than double, and the post-treatment roughness increased by 12.8% after peening CrNi steels and decreased by 7.8% after peening ZrO2 relative to the reference surfaces. Roughness has an identifiable effect on sliding wear resistance. Higher roughness promotes material loss. After the SP process, the coefficient of friction increased by 15.5% and 20.7%, while the wear factor (K) decreased by 25.9% and 32.7% for the samples peened with CrNi steels and ZrO2, respectively. Abrasive and adhesive mechanisms were dominant, featured with slight fatigue. The investigation showed a positive effect of SP on the tribological properties of DMSL 17-4PH.

Clinical practicality and patient performance for surface-guided automated VMAT gating for DIBH breast cancer radiotherapy

Background and purposeTo evaluate the performance of automated surface-guided gating for left-sided breast cancer with DIBH and VMAT. Materials and methodsPatients treated in the first year after introduction of DIBH with VMAT were retrospectively considered for analysis. With automated surface-guided gating the beam automatically switches on/off, if the surface region of interest moved in/out the gating tolerance (±3 mm, ±3°). Patients were coached to hold their breath as long as comfortably possible. Depending on the patient’s preference, patients received audio instructions during treatment delivery. Real-time positional variations of the breast/chest wall surface with respect to the reference surface were collected, for all three orthogonal directions. The durations and number of DIBHs needed to complete dose delivery, and DIBH position variations were determined. To evaluate an optimal gating window threshold, smaller tolerances of ±2.5 mm, ±2.0 mm, and ±1.5 mm were simulated. Results525 fractions from 33 patients showed that median DIBH duration was 51 s (range: 30–121 s), and median 4 DIBHs per fraction were needed to complete VMAT dose delivery. Median intra-DIBH stability and intrafractional DIBH reproducibility approximated 1.0 mm in each direction. No large differences were found between patients who preferred to perform the DIBH procedure with (n = 21) and without audio-coaching (n = 12). Simulations demonstrated that gating window tolerances could be reduced from ±3.0 mm to ±2.0 mm, without affecting beam-on status. ConclusionIndependent of the use of audio-coaching, this study demonstrates that automated surface-guided gating with DIBH and VMAT proved highly efficient. Patients’ DIBH performance far exceeded our expectations compared to earlier experiences and literature. Furthermore, gating window tolerances could be reduced.

Evaluating the Impact of the Recent Combined and Satellite-Only Global Geopotential Model on the Gravimetric Geoid Model

Geoid represents Earth’s surface, ocean, and gravitational field, which influence the elevations, shape, and mass distribution of the geopotential surface, a hypothetical surface that is perpendicular to the direction of gravity at every point. This geopotential surface serves as a reference for measuring elevations and is used as a fundamental reference surface for geodetic and surveying purposes. In this study, the Least Squares Modification of Stokes Formula (LSMS) with Additive Corrections (AC), also known as the KTH method, is used to generate a new gravimetric geoid model for Peninsular Malaysia. The KTH method was developed at the Royal Institute of Technology (KTH) in Stockholm-Sweden. The dataset used is the most recent global digital elevation model, Shuttle Radar Topography Mission (SRTM) 1 Arc-Second Global, generated by the National Aeronautics and Space Administration (NASA) and the National Imagery and Mapping Agency (NIMA). In addition to this elevation data, the dataset includes the Global Geopotential Model (GGM), which is composed of the XGM2016, XGM2019e, Tongji_GGMG2021S, and Tongji-Grace02k models. Furthermore, it incorporates sets of regional gravity data, including terrestrial gravity, airborne gravity, and marine gravity anomalies, all of which are derived from the Technical University of Denmark (DTU 21). The actual 45 Global Navigation Satellite System (GNSS)-levelling points data have been compared to the gravimetric geoid model developed in this study and the geoid acquired from Department of Survey and Mapping Malaysia (DSMM). According to the statistical results, NXGM2019e provides better accuracy, with the Root Mean Square Error (RMSE) geoid model errors of ±0.033 m, compared to the deviations in free-air anomalies, XGM2019e, which has the minimum RMSE of 10.291 mGal. Meanwhile, Tongji-GMMG2021S has the maximum RMSE of 14.792 mGal. The geoid is derived from the XGM2019e model and has maximum and minimum values of 0.032 m and 0.147 m, respectively, with mean residuals of 0.089 m. In conclusion, the XGM2019e has the potential to determine a precise local geoid model for Peninsular Malaysia

Asymptotic distribution of nodal intersections for ARW against a surface

We investigate Gaussian Laplacian eigenfunctions (Arithmetic Random Waves) on the three-dimensional standard flat torus, in particular the asymptotic distribution of the nodal intersection length against a fixed regular reference surface. Expectation and variance have been addressed by Maffucci [Ann. Henri Poincaré 20(11), 3651–3691 (2019)] who found that the expected length is proportional to the square root of the eigenvalue times the area of the surface, while the asymptotic variance only depends on the geometry of the surface, the projected lattice points being equidistributed on the two-dimensional unit sphere in the high-energy limit. He also noticed that there are “special” surfaces, so-called static, for which the variance is of smaller order; however he did not prescribe the precise asymptotic law in this case. In this paper, we study second order fluctuations of the nodal intersection length. Our first main result is a Central Limit Theorem for “generic” surfaces, while for static ones, a sphere or a hemisphere e.g., our main results are a non-Central Limit Theorem and a precise asymptotic law for the variance of the nodal intersection length, conditioned on the existence of so-called well-separated sequences of Laplacian eigenvalues. It turns out that, in this regime, the nodal area investigated by Cammarota [Trans. Am. Math. Soc. 372(5), 3539–3564 (2019)] is asymptotically fully correlated with the length of the nodal intersections against any sphere. The main ingredients for our proofs are the Kac-Rice formula for moments, the chaotic decomposition for square integrable functionals of Gaussian fields, and some arithmetic estimates that may be of independent interest.

Nature-inspired parylene/SiO2 core-shell micro-nano pillars: Effect of topography and surface chemistry

We investigated the synergy of surface topography and chemistry in micro/nanostructured pillars inspired by nature, specifically mimicking tokay gecko (Gekko gecko Linnaeus, 1758) feet and sacred lotus (Nelumbo nucifera Gaertn., 1788) leaves. The aim is to understand and replicate their adhesive and self-cleaning properties for diverse applications. Through a detailed fabrication process and chemical modifications, the surfaces exhibit superhydrophobic characteristics. The research precisely examines the fabrication of surfaces with well-defined micropillars using lithography and deep silicon substrate etching. Diverse surface treatments, including silanization and O2 plasma, are applied to tailor the chemical composition of microstructured surfaces. Utilizing a ≈ 5 nm thin SiO2 interface layer, the study reveals superhydrophobic properties post-silanization and an eightfold increase in adhesion force (FA) between the studied surface and reference surfaces. FA measurements using atomic force microscopy reveal an eightfold increase in adhesion on both flat and microstructured surfaces, emphasizing the transformative effects of microstructures on surface morphology. The findings highlight the potential for multifunctional surface designs, elucidating that superhydrophobic properties correlate with structure topography while FA amplitude is predominantly determined by surface termination. Inspired by nature, this research unveils novel possibilities in functional materials and surface engineering, with broad implications across various applications.

Four decades of global surface albedo estimates in the third edition of the CM SAF cLoud, Albedo and surface Radiation (CLARA) climate data record

Abstract. We present the surface albedo data in the third edition of the CM SAF cLoud, Albedo and surface Radiation (CLARA) data record family. The temporal coverage of this edition is extended from 1979 until the near-present day. The core algorithms and data format remain unchanged from previous editions, but now white- and blue-sky albedo estimates are also available for the first time in CLARA data. We present an overview of the retrieval, followed by an assessment of the accuracy and stability of the data record, based on collocated comparisons with reference surface albedo measurements and intercomparisons with preceding satellite-based albedo data records. Specific attention is paid to addressing the spatial representativeness problem inherent in the “point-to-pixel” validation of satellite-based coarse surface albedo estimates against in situ measurements. We find the CLARA-A3 albedo data to match or improve upon the accuracy and robustness of the predecessor record (CLARA-A2), with good agreement found when compared to in situ measurements. In cases of a large bias, the spatial representativeness of the measurement site typically explains most of the increase. We conclude with a summarizing discussion on the observed strengths and weaknesses of the new data record, including guidance for potential users. The data are available at https://doi.org/10.5676/EUM_SAF_CM/CLARA_AVHRR/V003 (Karlsson et al., 2023b).

Correlation between Disc Imaging Observations and Clinical Efficacy after Percutaneous Endoscopic Lumbar Discectomy: A 1-Year Follow-up Study.

The connection between alterations in the disc structure following percutaneous endoscopic lumbar discectomy (PELD) and symptoms in patients postsurgery has not been reported yet. The purpose of the present study was to discuss the potential correlation between the changes in the morphological characteristics of various reference surfaces of the intervertebral disc after percutaneous endoscopic lumbar discectomy (PELD) and clinical outcomes, to identify the morphological parameters that affect efficacy and provide an evidence-based foundation for assessing postoperative efficacy. From October 2019 to October 2021, after percutaneous endoscopic lumbar discectomy (PELD), 98 individuals were enrolled. MRI DICOM data of the lumbar spine were obtained before and after surgery, specifically around 3 months. The morphological parameters of the operated and adjacent segments of the discs were measured using T2-weighted images from three reference planes. Outcomes were assessed using the Oswestry disability index (ODI), visual analogue pain scores for the back and leg (VAS-back/VAS-leg), Japanese Orthopaedic Association (JOA) scores, and recovery rates. Postoperative changes in disc parameters and outcomes were compared between patients with different severity and types of LDH based on the MSU staging. Patients completed the questionnaire during outpatient follow-up appointments 3, 6, and 12 months after the surgery. The follow-up period was 14.69 ± 4.21 months, ranging from 12 to 24 months. Parameters such as area and circumference of intervertebral discs in the cross-section were not associated with the change in the efficacy index. Postoperatively, a negative correlation between the variation of the disc height, disc height index, and protrusion distance and the difference in VAS scores for low back pain at 3 and 6 months was observed among the two sagittal change parameters. Differences between changes in disc imaging parameters and postoperative efficacy were not statistically significant between various types of lumbar disc herniation. For the patients after percutaneous endoscopic lumbar discectomy, the changes in parameters such as disc area and circumference in the cross-sectional plane are not associated with efficacy, and the changes in disc height and herniation distance in the sagittal plane provide a morphologic basis for the assessment of short-term postoperative efficacy. In addition, the changes in disc morphologic parameters and postoperative efficacy do not differ between various types of lumbar disc herniation.

Manufacturing errors detection and visualization system for parts with complex internal cavity structural through industrial CT image

To address the challenge of detection and visualization manufacturing errors in part with complex internal cavity structures, this paper present a method based on industrial computed tomography (CT) image. First, a two-dimensional (2D) CT sequence slice images are obtained using fan-beam high energy industrial CT scanning, which is then reconstructed into a three-dimensional (3D) measurement model. The measurement 3D model is registered with the original design model, and the surface information of the part is obtained by segmenting the surfaces. The error between reference surface of original design model and test surface of measurement model is calculated. By comparing the error value with the tolerance, the detection result is obtained and analyzed. The developed software system enables areas that do not meet the tolerance requirements to be visualized. This method can detect manufacturing errors for part with complex internal cavity structures, such as planeness error, cylindricity error, verticality error, and parallelism error. This method provides a basis for assessing the manufacturing and processing quality of part with complex internal cavity structures.