Measurement Geometry Research Articles

Simultaneous measurement of surface geometry and film thickness distribution by retroreflex ellipsometry

Simultaneous measurement of surface geometry and film thickness distribution by retroreflex ellipsometry

Silicon-via (Si-via) hole metrology and inspection by grayfield edge diffractometry

This paper introduces a novel silicon-via (Si-via) hole metrology and inspection method based on grayfield edge diffractometry, enabling simultaneous measurement of Si-via hole geometry and roughness. The edge diffraction interferogram occurs when incident light interacts with the via edge. A grayfield imaging system consists of a pair of axicon lenses, two objective lenses and imaging system was developed to capture the fringes. Here, a pair of axicon lenses shape the collimated beam into a donut-shaped beam profile. The shaped beam has an adjustable focus point, allowing scanning along the Si-via hole depth axis. The cross-correlation approach to comprehensive analysis of the fringes was performed to extract via roundness and via-edge roughness (VER). The relationship between cross-correlation output and VER was characterized, assuming the line-edge roughness (LER) represents VER. The proposed method was cross-verified with the conventional microscopy approach. In addition, the through-focus scanning optical microscopy method was also used to intuitively characterize the fringe feature in three-dimension. In conclusion, the proposed method can characterize Si-via hole's roundness and estimate VER, showcasing potential adaptability for automated Si-via hole inspections in wafer-level hybrid bonding applications.

Determinants of growth differentiation factor 15 plasma levels in outpatients with peripheral arterial disease.

Growth differentiation factor 15 (GDF-15) is a robust prognostic biomarker in patients with cardiovascular (CV) disease, and a better understanding of its clinical determinants is desirable. We aimed to study the associations between GDF-15 levels and traditional CV risk factors, indicators of atherosclerotic burden, and cardiac geometry and dysfunction in outpatients with peripheral arterial disease (PAD). An explorative cross-sectional study (Study of Atherosclerosis in Vastmanland, Västerås, Sweden) included 439 outpatients with carotid or lower extremity PAD. The mean age was 70 years (standard deviation [SD] 7), and 59% of the patients were men. Plasma levels of GDF-15 were obtained along with potential determinants, including medical history, biochemical data, echocardiographic measures of cardiac geometry and function, ankle-brachial index (ABI), and carotid ultrasonographic data on intima-media thickness (IMT) and occurrence of carotid stenosis. The relations between GDF-15 concentrations (transformed with the natural logarithm) and the different determinants were evaluated using uni- and multivariable linear regression models. All pre-specified variables were included in the multivariable models. The multivariable analysis identified independent relations of GDF-15 with several of the included variables (adjusted R 2 = 0.48). Diabetes (beta coefficient [β] of 0.37, 95% confidence interval [95% CI] 0.25 to 0.50), low-density lipoprotein (LDL) cholesterol (β = -0.22, 95% confidence interval [CI]: -0.34 to -0.09), and physical activity (β = -0.16, 95% CI: -0.25 to -0.06) had the strongest associations. In contrast, no significant independent associations with GDF-15 level were observed for cardiac geometry and function, ABI, IMT, or carotid stenosis. Circulating GDF-15 is more strongly associated with traditional CV risk factors, especially diabetes, LDL cholesterol, and physical activity than with specific indicators of atherosclerotic burden or cardiac dysfunction. To better understand the pathophysiological role of GDF-15 and its link to clinical outcomes in patients with PAD, future studies should focus on the metabolic processes involved in atherosclerotic disease.

Precise Measurements of the LMC Bar’s Geometry with Gaia DR3 and a Novel Solution to Crowding-induced Incompleteness in Star Counting

Abstract We present new measurements of the 2D geometry of the LMC’s stellar bar with precise astrometric observations of red clump stars in Gaia DR3. We develop a novel solution to tackle crowding-induced incompleteness in Gaia data sets with the Gaia BP-RP color excess. Utilizing the color excess information, we derive a 2D completeness map of the LMC’s disk. We find that incompleteness biases the bar measurements and induces large uncertainties. With the completeness-corrected 2D red clump map, we precisely measure the LMC bar’s properties using Fourier decomposition. The bar radius (semimajor axis) is R bar = 2.13 − 0.04 + 0.03 kpc, and its position angle is 121.°26 ± 0.°21. The bar’s strength as quantified by the Fourier bi-symmetric amplitude is S bar = 0.27, indicating that the LMC has a significant bar perturbation. We find the bar has an axis ratio of 0.54 ± 0.03, and is offset with respect to the center of the outer disk isophote at R ≈ 5 kpc by 0.76 ± 0.01 kpc. These LMC bar properties agree with a hydrodynamic model where the SMC has undergone a recent direct collision with the LMC. We compare the LMC’s bar properties with other barred galaxies in the local Universe, and discover that the LMC is similar to other barred galaxies in terms of bar-galaxy scaling relations. We discuss how our completeness correction framework can be applied to other systems in the Local Group.

CTFFIND5 provides improved insight into quality, tilt, and thickness of TEM samples.

Images taken by transmission electron microscopes are usually affected by lens aberrations and image defocus, among other factors. These distortions can be modeled in reciprocal space using the contrast transfer function (CTF). Accurate estimation and correction of the CTF is essential for restoring the high-resolution signal in cryogenic electron microscopy (cryoEM). Previously, we described the implementation of algorithms for this task in the cisTEM software package (Grant et al., 2018). Here we show that taking sample characteristics, such as thickness and tilt, into account can improve CTF estimation. This is particularly important when imaging cellular samples, where measurement of sample thickness and geometry derived from accurate modeling of the Thon ring pattern helps judging the quality of the sample. This improved CTF estimation has been implemented in CTFFIND5, a new version of the cisTEM program CTFFIND. We evaluated the accuracy of these estimates using images of tilted aquaporin crystals and eukaryotic cells thinned by focused ion beam milling. We estimate that with micrographs of sufficient quality CTFFIND5 can measure sample tilt with an accuracy of 3° and sample thickness with an accuracy of 5 nm.

CTFFIND5 provides improved insight into quality, tilt, and thickness of TEM samples

Images taken by transmission electron microscopes are usually affected by lens aberrations and image defocus, among other factors. These distortions can be modeled in reciprocal space using the contrast transfer function (CTF). Accurate estimation and correction of the CTF is essential for restoring the high-resolution signal in cryogenic electron microscopy (cryoEM). Previously, we described the implementation of algorithms for this task in the cisTEM software package (Grant et al., 2018). Here we show that taking sample characteristics, such as thickness and tilt, into account can improve CTF estimation. This is particularly important when imaging cellular samples, where measurement of sample thickness and geometry derived from accurate modeling of the Thon ring pattern helps judging the quality of the sample. This improved CTF estimation has been implemented in CTFFIND5, a new version of the cisTEM program CTFFIND. We evaluated the accuracy of these estimates using images of tilted aquaporin crystals and eukaryotic cells thinned by focused ion beam milling. We estimate that with micrographs of sufficient quality CTFFIND5 can measure sample tilt with an accuracy of 3° and sample thickness with an accuracy of 5 nm.

A 3D Printed Air-Tight Cell Adaptable for Far-Infrared Reflectance, Optical Photothermal Infrared Spectroscopy, and Raman Spectroscopy Measurements

Material characterization and investigation are the basis for improving the performance of electrochemical devices. However, many compounds with electrochemical applications are sensitive to atmospheric gases and moisture; therefore, even their characterization should be performed in a controlled atmosphere. In some cases, it is impossible to execute such investigations in a glove box, and, therefore, in the present work, an air-tight 3D printed cell was developed that preserves samples in a controlled atmosphere while allowing spectroscopic measurements in reflectance geometry. Equipped with a cheap 1 mm thick CaF2 optical window or a more expensive 0.5 mm thick ZnS window, the cell was used for both optical photothermal infrared and Raman spectroscopy measures; imaging of the samples was also possible. The far-infrared range reflectance measurements were performed with a cell equipped with a diamond window.

Evaluation of Mathematical and Scientific Competences in Primary Education STEAM Projects in Spain: A Systematic Review

The aim of this article is to present an overview of the current state of the mathematical and scientific competences in Primary Education in Spain and how their development is assessed in STEAM experiences (with students of 6–12 years of age). To this end, a systematic review based on the PRISMA 2020 protocol was carried out in the Scopus, Web of Sciences, and Dialnet databases, analyzing all articles published from 1993 to 2022 relating to the subject. In total, 53 articles were selected, most published in the last five years and primarily in the Dialnet database. It was found that the majority of the targeted objectives in the experiences were related to STEAM competence, but only 14 evaluated aspects related to mathematical or scientific competence. The mathematical competence was evaluated by the measurement of geometry or number content and their corresponding operations and by how information data (statistics) are graphically represented. In a few cases, the evaluation is also related to computational thinking and orientation skills. In the case of scientific competence, its evaluation was mainly based on the assessment of the understanding of concepts, with those concepts being related to Physics in 80% of the cases. The only evaluated aspect of scientific competence other than concept understanding was hypothesis formulation, which was featured in two articles. These results highlight the need to systematically incorporate assessments that provide a clearer view of mathematical or scientific competence development in implementing STEAM experiences in primary education.

Relationship Between Urinary Uranium and Cardiac Geometry and Left Ventricular Function: The Strong Heart Study

BackgroundUranium is a potentially cardiotoxic, nonessential element commonly found in drinking water throughout the United States. ObjectivesThe purpose of this study was to evaluate if urinary uranium concentrations were associated with measures of cardiac geometry and function among American Indian young adults from the Strong Heart Family Study. MethodsUrinary uranium was measured among 1,332 participants free of diabetes, cardiovascular disease, and <50 years of age at baseline (2001-2003). Transthoracic echocardiography and blood pressure were assessed at baseline and at a follow-up visit (2006-2009). We estimated adjusted mean differences in cardiac geometry and function measures at baseline and follow-up using linear mixed-effect models with a random intercept and slope over time. ResultsMedian (interquartile range) uranium was 0.029 (0.045) μg/g creatinine. In fully adjusted cross-sectional models, a log-doubling of urinary uranium was positively associated with left ventricular (LV) mass index (mean difference: 0.49 g/m2, 95% CI: 0.07-0.92 g/m2), left atrial systolic diameter (0.01 cm/m2, 0.01-0.02 cm/m2), and stroke volume (0.66 mL, 0.25-1.08 mL) at baseline. Prospectively, uranium was associated with increases in left atrial diameter (0.01 cm/m2, 0.01-0.02 cm/m2), pulse pressure (0.28 mm Hg, 0.05-0.52 mm Hg), and incident LV hypertrophy (odds ratio: 1.25, 95% confidence interval: 1.06, 1.48). ConclusionsUrinary uranium levels were adversely associated with measures of cardiac geometry and LV function among American Indian adults, including increases in pulse pressure and LV hypertrophy. These findings support the need to determine the potential long-term subclinical and clinical cardiovascular effects of chronic uranium exposure, and the need for future strategies to reduce exposure.

The Effect of Reduced Ambient Pressure on Plume-Surface Interaction Cratering Dynamics

This study investigates the differences in plume-surface interaction (PSI) cratering behavior between Earth atmospheric (101,325 Pa) and subatmospheric (33 Pa) ambient pressures. A stereo-photogrammetry technique was used to nonintrusively obtain 3D, time-resolved measurements of the full-domain crater geometry. Tests were conducted inside an optically accessible vacuum chamber where the PSI process was simulated using a sonic jet impinging on a bed of regolith simulant. Crater geometry measurements were taken at nozzle heights of 4.6 to 55.6 nozzle diameters above the simulant surface. Results show that the highly underexpanded plume under subatmospheric conditions resulted in broad and shallow craters compared to craters formed under Earth atmosphere. Some craters under subatmospheric conditions exhibited lobed geometry characterized by azimuthal depth variations. In these same cases, the deepest portion of the crater was located radially away from the center, and particles were observed moving toward the center resulting in fountain-like particle movement. Craters formed under Earth atmospheric conditions had an axisymmetric parabolic geometry with the location of maximum depth at the center. In general, subatmospheric crater growth was slower than Earth atmospheric. However, subatmospheric crater formation at nozzle heights of 9.3D and below was characteristically like Earth atmospheric crater formation at large nozzle heights.

Identification method of cyclic top defects in track geometry measurements in its early stage

Track irregularities in the long wavelengths are often overlooked in the development of new track identification and detection techniques, yet they can have serious implications for the safety of freight wagons and the comfort of passengers. This study is aimed to extend the current published literature, by proposing a methodology for the identification and classification of evolving cyclic top (CT) irregularities in the mid and long wavelength range between 25 and 70 m. The methodology required a dataset of historical vertical track geometry measurements to identify and classify CT irregularities, by analysing the growing wavelength contents. The classification of detected CT into early and advanced stage of evolution allows maintenance interventions to be timely planned, improving transportation efficiency. This study contributes to enhancing monitoring methodologies for track geometry and highlights the importance of considering mid and long wavelength irregularities.

A filter calibration method for laser-scanned weld toe geometries

The scanning of weld seams can be used to evaluate the local weld toe geometry for fatigue assessments. Laser scanned weld seam profiles often contain noise which complicates the accurate measurement of the weld toe geometry. For that reason, filtering of the scanned data is necessary. The issue at hand is that a filtering method can significantly affect the measurement results. Therefore, a calibration of the filter input parameters is needed. In this study, a calibration method for filtered laser-scanned weld profiles is presented by using artificial weld toe geometries. The adjustment of different filter functions is achieved by using an optimization method on predefined weld toes with an artificial noise. The resulting input data for the filter functions is tested on a real specimen to verify the method. Through the calibration method it is possible to achieve satisfactory measurement results with precisely set input parameters for the filter functions. The most suitable filter functions for the measurement of the weld toe are the Gaussian and the Lowpass filter. Both functions are adequate as a universally applicable filter. For the evaluation of the measurement results of the radii and angles, a tolerance range is introduced, which is defined by the theoretically minimum measurable radii and angles. Using an adjusted Lowpass filter and a point distance of 0.07 mm set by the laser scanner, a measurement within the tolerance range of 0.2 mm is achievable for the weld toe radius. For the weld toe angle, the tolerance range of 1.5° is achieved for the majority of measurements.

25 years field test history and fatigue damage analysis for a scrapped ladle crane

Fatigue performances of ladle cranes will gradually decrease with the increase of service years. The service history and the fatigue damage of a scrapped ladle crane were investigated and analyzed in this paper. The test history of the ladle crane was collected and concluded, and the statistical parameters of lifting capacity and the crack condition during service were determined. The last comprehensive field test before scrapping the ladle crane was introduced in detail and the damage evolution was analyzed. The geometry measurement showed that the main girders’ stiffness had changed obviously. The stress test of the crack-prone positions of the metal structure revealed their remaining bearing capacity and the damage evolution characteristics. Further analysis proved that the static stiffness of the main girder has a closer relationship with damage deterioration. Some material property inspections were carried out for samples cut from the scrapped crane’s main girder, which were of the load-carrying part and the non-load-carrying part respectively. Results showed that the elastic modulus and hardness of the materials decreased evidently after service, while other mechanical properties did not change significantly. This study will provide useful references for further understanding of the fatigue characteristics and evolution behaviors of ladle cranes.

Hip geometry and strength remain stable the first year after kidney transplantation—an ibandronate/placebo post hoc analysis

Abstract The sensitivity of bone mineral density (BMD) to identify patients with high fracture risk after kidney transplantation is low, therefore alternative tools are needed. Hip Structure Analysis (HSA) provides an estimation of hip structural geometry and strength based on conventional DXA scans for hip analyses. We aimed to investigate the effect of antiresorptive therapy on hip geometrical and strength parameters by HSA. In a post hoc analysis of a 12-month randomized, double-blind, placebo-controlled trial evaluating the effect of ibandronate in addition to active vitamin D and calcium in kidney transplant recipients (KTR), we re-analyzed dual total hip and femoral neck DXA scans to measure cortical bone thickness (CBT) in the femoral neck (CBTNECK), calcar (CBTCALCAR), and shaft (CBTSHAFT), along with femur neck width, hip axis length, and to estimate buckling ratio and strength index. DXA measurements were performed within 5 weeks after transplantation and repeated at 10 weeks and 1-year post-transplant. The study included a total of 127 de novo KTR with estimated glomerular filtration rate &amp;gt;30 mL/min at baseline. The 5 geometrical and the strength and stability hip parameters remained stable over the first post-transplant year irrespective of antiresorptive therapy. We detected no statistically significant between-group differences in any of the HSA measures. Change in geometrical hip parameters and buckling ratio over the study duration was not correlated with change in plasma parathyroid hormone or change in dual total hip BMD. In this study, the so far largest of HSA in KTR, antiresorptive therapy with ibandronate for 12 months did not affect measures of hip geometry or strength. Clinical Trial Registration: www.clinicaltrials.gov as NCT00423384, EudraCT number 2006-003884-30.

The impact of neurological impairment and tone on hip joint development.

The purpose of this study was to define how different force environments by neuromuscular diagnosis (hypertonic versus hypotonic) impact the growth and morphology of the proximal femoral and acetabular regions relative to typically developing children. Children with cerebral palsy and spinal muscular atrophy were compared with typically developing children aged 6 months to 11 years. Routine pelvic radiographs were evaluated using measures of hip geometry for the proximal femur and acetabulum. The data were analyzed using general linear models to estimate the developmental patterns according to age and diagnosis. One hundred eighty-four children met the inclusion criteria: 58 spastic cerebral palsy Gross Motor Function Classification System I-V (263 hips), 32 spinal muscular atrophy (79 hips)), and 94 typically developing (187 hips) were included with a mean age of 4.9 ± 3.1 years. Using spinal muscular atrophy as a reference, significant differences in proximal femoral development included long thin versus short neck (p < 0.01) and round versus flat epiphysis (p = 0.001). A thin neck-wide epiphysis was found in spinal muscular atrophy versus thick neck-small epiphysis for typically developing (p < 0.05). The ratio of acetabular width to proximal femoral epiphysis width differed significantly for typically developing (p = 0.001) compared with cerebral palsy and spinal muscular atrophy. There was a negative correlation between migration percentage and acetabular width to epiphysis width in children with cerebral palsy, but no correlation in children with spinal muscular atrophy. Hip geometry was impacted by the force environment experienced during growth. These findings emphasize the crucial roles of gross motor function, muscle tone, and strength differences in determining hip morphology. III, retrospective case control.

Natural geometrical variations of Italian Phyllostachys edulis bamboo culms for construction purposes

Amid the increasing scarcity of raw materials, utilizing bamboo as a renewable building material offers significant environmental and economic benefits for the European construction sector. However, in Europe, the use of bamboo for construction remains limited due to a lack of studies on geometrical and material characteristics of European-cultivated bamboo species. Although bamboo is not typically grown in Europe, the number of bamboo plantations is steadily increasing in countries like Spain, France and Italy. Bamboos growing in temperate climates, however, are exposed to different environmental conditions during growth compared to bamboos from subtropical and tropical climates, such as those in China or Vietnam. As bamboo’s geometric properties are strongly influenced by the environmental conditions during growth, it is essential to investigate how bamboo culms of the same species grown in Europe compare to those from other regions. The present article reports findings on the geometry and geometric imperfections of 90 four-meter Italian bamboo culms. First, the Italian Phyllostachys edulis bamboo culms examined in this study are briefly introduced. Following, geometric imperfections of bamboo culms are defined, and the geometry measurement concept is presented. Subsequently, variations in internode lengths, diameters, wall thicknesses, ovalities, stem tapers and pre-deflections are described and analyzed. Finally, the findings from the Italian culms are compared with those from Asian Phyllostachys edulis. In summary, this article enhances the understanding of the geometric properties of bamboo grown in Europe, thereby advancing the use of cultivated bamboo culms in Europe and improving the overall understanding of bamboo characteristics across different climatic zones.

Laser Scan Compression for Rail Inspection

The automation of rail track inspection addresses key issues in railway transportation, notably reducing maintenance costs and improving safety. However, it presents numerous technical challenges, including sensor selection, calibration, data acquisition, defect detection, and storage. This paper introduces a compression method tailored for laser triangulation scanners, which are crucial for scanning the entire rail track, including the rails, rail fasteners, sleepers, and ballast, and capturing rail profiles for geometry measurement. The compression technique capitalizes on the regularity of rail track data and the sensors’ limited measurement range and resolution. By transforming scans, they can be stored using widely available image compression formats, such as PNG. This method achieved a compression ratio of 7.5 for rail scans used in the rail geometry computation and maintained rail gauge reproducibility. For the scans employed in defect detection, a compression ratio of 5.6 was attained without visibly compromising the scan quality. Lossless compression resulted in compression ratios of 5.1 for the rail geometry computation scans and 3.8 for the rail track inspection scans.

Performance of a Radio-Frequency Two-Photon Atomic Magnetometer in Different Magnetic Induction Measurement Geometries.

Measurements monitoring the inductive coupling between oscillating radio-frequency magnetic fields and objects of interest create versatile platforms for non-destructive testing. The benefits of ultra-low-frequency measurements, i.e., below 3 kHz, are sometimes outweighed by the fundamental and technical difficulties related to operating pick-up coils or other field sensors in this frequency range. Inductive measurements with the detection based on a two-photon interaction in rf atomic magnetometers address some of these issues as the sensor gains an uplift in its operational frequency. The developments reported here integrate the fundamental and applied aspects of the two-photon process in magnetic induction measurements. In this paper, all the spectral components of the two-photon process are identified, which result from the non-linear interactions between the rf fields and atoms. For the first time, a method for the retrieval of the two-photon phase information, which is critical for inductive measurements, is also demonstrated. Furthermore, a self-compensation configuration is introduced, whereby high-contrast measurements of defects can be obtained due to its insensitivity to the primary field, including using simplified instrumentation for this configuration by producing two rf fields with a single rf coil.

Real-Time Video Processing for Measuring Zigzag Length of Pantograph–Catenary Systems Based on GPS Correlation

Recent years have seen outstanding developments in research and technology, highlighting the importance of railway transportation, especially the implementation of high-speed trains, which is becoming more and more challenging. This facilitates extensive research into the science and technology of the electrical interaction between the components of pantograph–catenary systems (PCSs). Problems regarding the PCS can result in infrastructure incidents, potentially stopping train operations. A common cause of failure in electrified railway PCS is a contact wire’s zigzag length that exceeds the prescribed technical limit, which can be caused by missing droppers or faults in the mounting mechanism. This work proposes a video camera-based monitoring technique for zigzag geometry measurement that additionally employs a Global Positioning System (GPS) sensor to detect the current geographical position of the point of zigzag length measurement. There are two proposed techniques for measuring the length of the zigzag based on image processing. In the first technique, using previously recorded data, the images are analyzed in the laboratory, and in the second, the images are analyzed in real time. Based on the results, we suggest a model and prediction of zigzag length employing hybrid deep neural networks.

A Review of the Application of the Laser-Light Backscattering Imaging Technique to Agricultural Products

Growing concerns about food safety and waste have increased consumer demand for high-quality agricultural products, particularly at the postharvest stage. This demand has prompted the development of non-destructive methods to assess or inspect the internal quality of fruits and vegetables. The backscattering imaging technique, also known as diffuse reflectance imaging, is considered a highly promising approach. Numerous studies have focused on practical applications, using laser light at selected wavelengths to develop quick multispectral methods. Due to the rapid interaction of photons with biological tissue, together with the highly computational performance of machine vision, backscattering imaging can offer a valuable alternative to traditional methods. Its primary benefits include quick measurements without chemical sample preparation, easy integration with high-throughput automatic quality control, and reduced waste, since this non-destructive technique does not damage samples. This review presents a comprehensive overview of backscattering imaging, including the measurement geometry, data analysis, and design considerations for vision systems. Additionally, it explores this technique’s advantages, challenges, and accuracy, as demonstrated using various case studies.