Surface Profiler Research Articles

Custom chromatic confocal microscope for surface profilometry

In this work, a surface profiling system is introduced, employing a custom-designed chromatic confocal (CC) distance sensor. Today’s commercial sensors based on the CC principle have a major drawback of effectively coupling light from the illumination source into the optical imaging system, mainly due to etendue mismatch. Consequently, a substantial amount of light is lost, significantly reducing the overall SNR of the system. This limitation restricts its applicability primarily to highly reflective surfaces. To address this issue, an etendue-matched optical system is proposed, that incorporates an innovative superluminescent light source. Through this approach, the system achieves 4 orders of magnitudes higher illumination intensity concentrated within the focus spot compared to existing devices in the current market.

Picometer-Sensitivity Surface Profile Measurement Using Swept-Source Phase Microscopy

In recent years, the Swept-Source Phase Microscope (SS-PM) has gained more attention due to its greater robustness to sample motion and lower signal decay with depth. However, the mechanical wavelength tuning of the swept source creates small variations in the wavenumber sampling of spectra that introduce serious phase noise. We present a software post-processing method to eliminate phase noise in SS-PM. This method does not require high-quality swept light sources or high-precision synchronization devices and achieves ~72 pm displacement sensitivity using a conventional SS-PM system. We compare the performance of this method with traditional software-based methods by measuring phase fluctuations. The phase fluctuations in the traditional software-based method are five times those of the proposed method, which means the proposed method has better sensitivity. Using this method, we reconstructed phase images of air wedges and resolution plates to demonstrate the SS-PM’s potential for high-sensitivity surface profiling measurement. Finally, we discuss the advantages of SS-PM over traditional Spectral-Domain PM techniques.

Evaluating the damage of collapsed bridges using remote sensing technologies: Case study: Baltimore’s Francis Scott Key Bridge

Bridges are vital for linking communities and facilitating economic activity. However, in the face of disaster, like ship collisions pose a significant threat to bridge infrastructure, causing structural damage and potential safety hazards. Rapid and precise assessment of the damage is essential for effective emergency response and recovery operations. Remote sensing with near-real-time satellite imagery provides the disaster scenario. This paper presents a change detection using pre- and post-disaster satellite data for Baltimore’s Francis Scott Key Bridge to identify structural damage due to the collision of the ship with support pillars on 26 March 2024. Both optical and microwave satellite data were used from open data sources and analyzed based on geospatial techniques such as change detection and surface profiling. It is estimated that an 1100-meter span of bridge was affected due to this collision, which helped to estimate the damage and mobilize the rescue operations. It may need further validation from ground truth information. Hence, the current study emphasizes the potential of remote sensing satellite data to provide near-real-time impact on disaster analysis.

2-Axis controlled spray pyrolysis deposition device for Dye-sensitized Solar Cell (DSSC)

Dye-sensitized solar cells (DSSCs) are a promising alternative to traditional silicon-based photovoltaic systems due to their efficient light-to-electricity conversion. A critical component of DSSCs is titanium dioxide (TiO2), responsible for converting light into electrical energy. Spray pyrolysis was one of the methods for fabricating TiO2 thin films. However, there are several drawbacks, such as challenges in particle size control, maintaining homogeneity of the thin film, and scalability issues during the deposition process. Modifications to the manufacturing process are necessary to achieve optimal performance in DSSCs, particularly with the thickness of the cell. This work focuses on the 2-axis spray pyrolysis process, a cost-effective way to create thin and thick films. In particular, it focuses on TiO2 thin films utilized as working electrodes in DSSC applications. The method was performed at different motor speeds, namely MS80, MS100, and MS120. The X-ray diffraction (XRD) spectrum showed that the dominance of the anatase phase appeared in an MS100. The UV-Vis results depict that the band gap value is 3.02 eV. The surface profiler analysis indicates that sample MS100 has an optimal thickness of 15.17 µm. The DSSC achieved 9.4% efficiency with sample MS100. This finding demonstrates that using 2-axis controlled spray pyrolysis deposition improves DSSC performance with an optimal motor speed.

Axial length association with corneoscleral sagittal height and scleral asymmetry.

To determine how corneoscleral geometry changes with axial length and to assess the usefulness of including the sagittal configuration of the anterior segment when predicting the axial length. An observational study was performed including 96 healthy subjects (96 eyes). Axial length was calculated from optical biometry (IOL Master 500). Corneal curvature and scleral sagittal height parameters at 13, 14 and 15 mm were obtained automatically using corneoscleral topography (eye surface profiler; ESP). In addition, corneal and scleral sagittal heights at numerous locations (21 radii: 0-10 mm from the corneal apex at 12 angles: 0-330°) were calculated using the raw height data extracted from the ESP. The relationships between axial length and the study parameters were analysed using Pearson correlation analysis. The equations for the prediction of axial length were obtained by fitting multiple linear regression models. The temporal-nasal scleral asymmetry at 13-, 14- and 15-mm chord lengths was significantly correlated with axial length (r2 ≤ 0.26; p < 0.001). Significant inverse correlations were found between the temporal scleral sagittal height and axial length (r2 ≤ 0.28; p ≤ 0.02). The nasal scleral sagittal height was not associated with axial length. Three significant multiple linear regression models were fitted based on spherical equivalent, corneal radius and scleral asymmetry at 13 (r2 = 0.79; p < 0.001), 14 (r2 = 0.80; p < 0.001) and 15 (r2 = 0.80; p < 0.001) mm chord lengths. Larger ocular globes show reduced temporal-nasal scleral asymmetry, mainly due to the lower sagittal height of the temporal sclera. Thus, the geometry of the temporal scleral may be a factor of interest during myopia progression.

Efficient Strategy to Discover DNA Aptamers Against Low Abundance Cell Surface Proteins in Scarce Samples.

Molecular recognition probes targeting cell surface proteins such as aptamers play crucial roles in precise diagnostics and therapy. However, the selection of aptamers against low-abundance proteins in situ on the cell surface, especially in scarce samples, remains an unmet challenge. In this study, we present a single-round, single-cell aptamer selection method by employing a digital DNA sequencing strategy, termed DiDS selection, to address this dilemma. This approach incorporates a molecular identification card for each DNA template, thereby mitigating biases introduced by multiple PCR amplifications and ensuring the accurate identification of aptamer candidates. Through DiDS selection, we successfully obtained a series of high-quality aptamers against cell lines, clinical specimens, and neurons. Subsequent analyses for target identification revealed that aptamers derived from DiDS selection exhibit recognition capabilities for proteins with varying abundance levels. In contrast, multiple rounds of selection resulted in the enrichment of only one aptamer targeting a high-abundance target. Moreover, the comprehensive profiling of cell surfaces at the single-cell level, utilizing an enriched aptamer pool, revealed unique molecular patterns for each cell line. This streamlined approach holds promise for the rapid generation of specific recognition molecules targeting cell surface proteins across a broad range of expression levels and expands its applications in cell profiling, specific probe identification, biomarker discovery, etc.

Evaluating the damage of collapsed bridges using remote sensing technologies: Case study: Baltimore’s Francis Scott Key Bridge

&lt;p class="MsoNormal" style="line-height: 120%; layout-grid-mode: char; mso-layout-grid-align: none; margin: 12.0pt 0cm 6.0pt 147.4pt;"&gt;&lt;span lang="EN-US" style="font-size: 10.0pt; line-height: 120%; mso-fareast-font-family: 'Times New Roman'; mso-font-kerning: 0pt; mso-fareast-language: JA; mso-no-proof: no;"&gt;Bridges are vital for linking communities and facilitating economic activity. However, in the face of disaster, like ship collisions pose a significant threat to bridge infrastructure, causing structural damage and potential safety hazards. Rapid and precise assessment of the damage is aid for effective emergency response and recovery operations. Remote sensing with near real-time satellite imagery provides the disaster scenario. This paper presents a change detection using pre and post-disaster satellite data for Baltimore&amp;rsquo;s Francis Scott Key Bridge to identify structural damage due to the collision of the ship with support pillars on 26 March 2024. Both optical and microwave satellite data were used from open data sources and analyzed based on geospatial techniques such as change detection and surface profiling. It is estimated that an 1100 m span of bridge was affected due to this collision, which helped to estimate the damage and mobilize the rescue operations. It may need further validation from ground truth information. Hence, the current study emphasizes the potential of remote sensing satellite data to provide near-real-time impact on disaster analysis.&lt;/span&gt;&lt;/p&gt;

Ultrafast and Chemoselective Biotinylation of Living Cell Surfaces for Time-Resolved Surfaceome Analysis.

Cell surface proteins participate in many important biological processes, such as cell-to-cell interaction, signal transduction, cell adhesion, and protein transportation. In-depth study of the cell surface protein group is of great significance. Nevertheless, detection and analysis of the surfaceome remain a significant challenge due to their low abundance and hydrophobicity. Herein, we reported an ultrafast and chemoselective labeling method using our newly developed trifunctional probe, the OPA-S-S-alkyne, which labeled cell surface lysine residues, and then established a novel cell surfaceome profiling approach. According to our experimental results, the OPA-S-S-alkyne probe can react extremely fast with living cells, labeling cells in only 1 min, while traditional NHS (labeling cell surface lysine with N-hydroxysuccinimide ester probe) and CSC (labeling cell surface glycan with hydrazide biotin probe) methods normally take longer time of more than 30 min and 1 h, respectively. Taking advantage of this ultrafast property of the method, we highlight the utility of this method by exploring the temporal dynamic changes of surfaceome upon EGF stimulation in living Hela cells and reported "early" and "late" EGF-regulated cell surface proteins, which are difficult to be distinguished by the current cell surface profiling approaches.

Fabrication of micropatterned PCL-collagen nanofibrous scaffold for cellular confinement induced early osteogenesis

The intricate interaction of the scaffold's architecture/geometry and with the cells is essential for tissue engineering and regenerative medicine. Cells sense their surrounding dynamic cues such as biophysical, biomechanical, and biochemical, and respond to them differently. Numerous studies have recently explored and reported the effect of contact guidance by culturing various types of cells on different types of micropatterned substrates such as microgrooves, geometric (square and triangle) micropattern, microstrips, micropatterned nanofibers. Amongst all of these micropatterned polymeric substrates; electrospun nanofibers have been regarded as a suitable substrate as it mimics the native ECM architectures. Therefore, in the present study; stencil-assisted electrospun Grid-lined micropatterned PCL-Collagen nanofibers (GLMPCnfs) were fabricated and its influence on the alignment and differentiation of pre-osteoblast cells (MC3T3-E1) was investigated. The randomly orientated Non-patterned PCL-Collagen nanofibers (NPPCnfs) were used as control. The patterns were characterized for their geometrical features such as area and thickness of deposition using surface profiler and scanning electron microscopy. A 61 % decrease in the overall area of GLMPCnfs as compared to the stencil area demonstrated the potential of electrofocusing phenomenon in the process of patterning electrospun nanofibers into various micron-scale structures. The MC3T3-E1 cells were confined and aligned in the direction of GLMPCnfs as confirmed by a high cellular aspect ratio (AR = 5.41), lower cellular shape index (CSI = 0.243), and cytoskeletal reorganization assessed through the F-actin filament immunocytochemistry (ICC) imaging. The aligned cells along the GLMPCnfs exhibited elevated alkaline phosphatase activity and enhanced mineralization. Furthermore, the gene expression profiling revealed upregulation of key osteogenic markers, such as ALP, OCN, OPN, COL1A1, and osteocyte markers DMP1, and SOST. Consequently, the research highlights the impact of GLMPCnfs on the cellular behaviour that results to the pre-osteoblast differentiation and the potential for stimulant-free early osteogenesis. These results offer an extensive understanding and mechanistic insight into how scaffold topography can be modified to influence cellular responses for effective bone regeneration strategies.

Influence of Elements in Steel With Anode Plasma Electrolytic Boriding on Hardness Gradient and Tribological Properties

Abstract The influence of elements in steel on anode plasma electrolytic boriding has been studied. The modified layers and surfaces on steel samples were analyzed by a scanning electron microscope, an X-ray diffractometer, a surface profiler, a microhardness tester, and a ball-disc tribometer. With 1045 steel as the control group, the same treatment parameters (treatment with 5 min, 200 V of voltage, 5% boric acid, and 10% ammonium chloride) were implemented on various steel substrates. It was found that a low content of carbon would hinder the penetration of boron, and other metallic elements can improve the mircrohardness gradient and decrease the wear-rate. Chromium and manganese can increase the maximum microhardness than treated 1045 by about 15%, but have a detrimental effect on surface flatness. Nevertheless, manganese has the ability to rapidly create a layer of oxide that enhances the tribological characteristics, leading to a remarkably low average friction coefficient of 0.26 for 1046 steel. The presence of molybdenum in the element composition of 4140 steel results in a notable enhancement of surface properties, namely in terms of wear resistance, with a minimum wear-rate 2.1 × 10−6 g/Nm for 4140 steel. Nickel does not appear to have a notable impact on the surface characteristics of the modified samples.

A three-degrees-of-freedom motion error measurement system based on Mach–Zehnder interferometry

This paper proposes a three-degree-of-freedom motion error measurement system based on Mach–Zehnder interferometry. The system consisted of an optical flat, beam-splitting prisms, and a reflector. When the stage was moving, the straightness error of the linear guides changed the optical path difference, which in turn caused a phase shift in the interferogram. This phase shift could be calculated by utilizing an image processing algorithm that was also developed during this study. The 3-DOF straightness errors, which included one linear error and two angular errors could be calculated. A commercial laser interferometer and a chromatic confocal sensor were used as reference sensors. The experimental results showed that the linear and angular measurement errors of the system were within ± 0.05 μm and ± 0.3″, respectively over measurement ranges of 100 mm and 60″. The repeatability, which was expressed by the standard deviation, was within 40 nm and 0.3″ for the linear and angular measurements, respectively. The proposed Mach-Zehnder interferometer has been successfully applied in a high-accuracy 3D surface topographic measurement system. It was able to effectively compensate the motion error and improve the accuracy for surface profiling.

Design and Experiment of Ordinary Tea Profiling Harvesting Device Based on Light Detection and Ranging Perception

Due to the complex shape of the tea tree canopy and the large undulation of a tea garden terrain, the quality of fresh tea leaves harvested by existing tea harvesting machines is poor. This study proposed a tea canopy surface profiling method based on 2D LiDAR perception and investigated the extraction and fitting methods of canopy point clouds. Meanwhile, a tea profiling harvester prototype was developed and field tests were conducted. The tea profiling harvesting device adopted a scheme of sectional arrangement of multiple groups of profiling tea harvesting units, and each unit sensed the height information of its own bottom canopy area through 2D LiDAR. A cross-platform communication network was established, enabling point cloud fitting of tea plant surfaces and accurate estimation of cutter profiling height through the RANSAC algorithm. Additionally, a sensing control system with multiple execution units was developed using rapid control prototype technology. The results of field tests showed that the bud leaf integrity rate was 84.64%, the impurity rate was 5.94%, the missing collection rate was 0.30%, and the missing harvesting rate was 0.68%. Furthermore, 89.57% of the harvested tea could be processed into commercial tea, with 88.34% consisting of young tea shoots with one bud and three leaves or fewer. All of these results demonstrated that the proposed device effectively meets the technical standards for machine-harvested tea and the requirements of standard tea processing techniques. Moreover, compared to other commercial tea harvesters, the proposed tea profiling harvesting device demonstrated improved performance in harvesting fresh tea leaves.

SiC plasma characterization produced by 3 ns pulse laser at 1010 W/cm2 intensity

A silicon carbide (SiC) plasma has been produced by a Q-switched laser at 1064 nm, 3 ns pulse and 1010 W/cm2 intensity, in high vacuum to investigate the fundamental mechanisms of laser-semiconductor interaction. Although the high hardness and chemical stability restrain the SiC micromachining, it is a valuable semiconductor for devices working under extreme conditions. The plasma has been characterized by using time-of-flight (TOF) measurements of ions detected by an ion collector ring (ICR) and an ion energy analyzer (IEA). Fast CCD camera, quadrupole mass spectroscopy (QMS) and surface profiler have been employed to provide deep insights into the laser-SiC interaction mechanisms. Ion kinetic energies, charge states, plasma expansion velocity, ablation yield per laser pulse, plasma temperature and density have been measured. Applications of the laser-generated plasma are presented and discussed.

Ultra-wide range non-contact surface profilometry based on reconfigurable fiber interferometry.

Surface characterization is essential for a technical evaluation of device performance and to assess surface dynamics in fabrication units. In this regard, a number of surface profiling techniques have been developed that accurately map sample topography but have significantly limited detection range. Here, we demonstrate a cascaded non-contact fiber interferometer-based approach for real-time high-precision surface profiling with ultrawide detection range (nm to mm). This compact interferometers' system operates by wavelength interrogation that provides a scope to study several types of surfaces and has a tunable cavity configuration for varying the sensitivity and range of the detectable features' size. The proposed system enables nanoscale profiling over 10-1000 nm with resolution of 10 nm and microscale mapping over 1-1000 µm with resolution of 0.2 µm. The technique is utilized to map the features of nanostructured surfaces and estimate the surface roughness of standardized industrial samples.

Fracture mechanisms of selective laser sintered parts manufactured in build direction

Selective laser sintering (SLS) is an additive manufacturing process that, in addition to rapid prototyping, is becoming increasingly popular to produce end-use parts. Predictable mechanical properties of the produced parts through this process is a desired primary goal. It has long been known that the mechanical properties especially the elongation at break of SLS components decrease in the build direction. In various test series with tensile specimen fabricated in build direction by SLS, it was found that, on the one hand, these have a very large scatter of the elongation at break, and, on the other hand, it was noticed that these frequently break outside the test range in the upskin radius. The upskin area describes regions that point in a positive build direction relative to the building plate. The fracture occurs at a point where, due to the specimen cross-section, a lower fracture stress occurs than in the test area of the specimen. This fracture leads to a much lower elongation at break than in the case of specimens that fracture in the test area. This study investigates which mechanism triggers this behavior. It turns out that different roughnesses can be determined in the upskin and downskin radius and different defects can be seen in the fracture surfaces, especially in the edge areas. It cannot be predicted based on surface roughness measurements or surface profiling exactly where, or in which layer the fracture occurs. However, the defects lead to a local stress spike, at which the failure of the specimen begins.

Tribological behaviour of a-C:H films with Cu cover layers: Formation and influence of tribo-induced Cu/Cu2O nanograins

This study focuses on the tribological behaviour of Cu-layer covered a-C:H films and the transfer film formation mechanisms, by means of tribological test, surface profiling, Raman spectroscopy and in-depth transmission electron microscopy, etc. Results showed that introducing a Cu cover layer with proper thickness would significantly enhance the tribological performance of a-C:H films at low sliding speed. The CoF of a-C:H was reduced to 0.004 (superlubricating) at the optimal Cu-layer thickness of ∼32 nm. The transferred material on counterpart was composed of a dense Cu layer and an a-C/(nc-Cu/Cu2O) composite layer, which promoted the formation of a similar layer on a-C:H wear track. The strength and durability of a-C/(nc-Cu/Cu2O) composite layer was double-reinforced by “physical pinning” and Cu-O-C “chemical bonding”.

Global flattening realization and kinematic analysis of UV-assisted low-speed 3D dynamic friction-polished diamonds

Diamond has attracted extensive attention from many scholars because of its unique properties. However, there are still bottlenecks in how to achieve high efficiency polishing and global flattening of diamond which restrict its application. The aim of this study is to obtain a globally homogeneous flattened diamond surface in macro dimension by introducing a compound motion of the polished workpiece. It is shown that ultra-smooth diamond surface machining with global flattening can be realized by UV-assisted low-speed dynamic friction polishing technique, and the typical roughness is 0.175 nm as measured by 3D optical surface profiler. These experimental results demonstrate that the catalytic phase transition process of UV light is the underlying mechanism to realize the diamond surface polishing under low rotational speed conditions. Additionally, the composite motion of the diamond sample with the metal disk brings large enhancement to the effect of polishing global flattening on the sample surface. The theoretical and experimental studies in this paper provide novel ideas for achieving efficient and polished global flattening of diamond.

Fluorescence-Based Calibration Model for In-Situ Measurement of Micro-scaled Lubricant Thickness Distribution at Indentation Interface

This study proposes a model for the measurement of microscale liquid film thickness distribution using fluorescence signals. The interfacial conditions between the tool and the workpiece in mechanical machining are important for understanding these phenomena and mechanisms. In this study, indentation tests with transparent tools were used to observe interfaces; however, it was challenging to obtain the signal from a thin fluorescent liquid film on smooth and steeply inclined surfaces. Therefore, fluorescence-based measurement, such as laser-induced fluorescence, was employed. To measure the absolute thickness of the thin fluorescent film, calibration of the measurement system is necessary. Therefore, a theoretical model was proposed considering the multiple reflections of excitation light and fluorescence at the inclined surface between the indenter and workpiece. By measuring the profile of the surface topography of the indented workpiece and comparing the results with those measured by a surface profiler, the validity of the proposed calibration method and the performance of this measurement system were demonstrated. The measured surface profiles, including scratches of 2–4 µm, were in good agreement, demonstrating the validity of the proposed method.

Deep learning-based predictive models for pavement patching and manholes evaluation

ABSTRACT Deep Learning (DL) techniques have been applied to the processing and evaluation of pavement conditions. DL-based predictive models are rapid and have higher accuracy compared to traditional methods. In this research, some models were developed to appraise pavement patching by considering the severity and the manhole cover utilising images collected by the Road Surface Profiler (RSP) from Bus Rapid Transit (BRT) lines in Tehran, Iran. Two cases (scenarios) were regarded in this research: 1) Patching without considering the severity, and 2) Patching by considering the severity. YOLOv5, YOLOv6, and YOLOv7 as one-stage object detection algorithms, and Faster R-CNN (ResNet-50) and Faster R-CNN (MobileNet_v3) as two-stage object detection algorithms were evaluated to choose the desired algorithm. The results exhibited that the trained model on YOLOv5 has better performance and is faster than the rest of the algorithms. In addition, the influence of the classes’ combination on model performance was scrutinised. Based on the results of the other classes, the outcomes of the study suggested that the model can detect and train better when the model is trained by a dataset with all classes. Furthermore, the performance of the model was also investigated by examining the effect of image size and YOLOv5's architectures. Based on the obtained results, YOLOv5 and an image size of 640*640 outperformed the rest. In Case 1, the precision, recall, F1-score, and mAP were 75.8%, 67.4%, 71.35%, and 77.4%, respectively. Moreover, the values of these metrics in Case 2, were 70%, 61.2%, 65.3%, and 64.4%, respectively. Hence, the results demonstrated that the developed model can be used with high performance in the detection and evaluation of pavement patching by severity, and manholes in Pavement Management Systems (PMS) and maintenance and rehabilitation plans.

Transdermal Delivery of Niacin Through Polysaccharide Films Ameliorates Cutaneous Flushing in Experimental Wistar Rats.

Niacin, an established therapeutic for dyslipidemia, is hindered by its propensity to induce significant cutaneous flushing when administered orally in its unmodified state, thereby constraining its clinical utility. This study aimed to fabricate, characterize, and assess the in-vitro and in-vivo effectiveness of niacin-loaded polymeric films (NLPFs) comprised of carboxymethyl tamarind seed polysaccharide. The primary objective was to mitigate the flushing-related side effects associated with oral niacin administration. NLPFs were synthesized using the solvent casting method and subsequently subjected to characterization, including assessments of tensile strength, moisture uptake, thickness, and folding endurance. Surface characteristics were analyzed using a surface profiler and scanning electron microscopy (SEM). Potential interactions between niacin and the polysaccharide core were investigated through X-ray diffraction experiments (XRD) and Fourier transform infrared spectroscopy (FTIR). The viscoelastic properties of the films were explored using a Rheometer. In-vitro assessments included drug release studies, swelling behavior assays, and antioxidant assays. In-vivo efficacy was evaluated through skin permeation assays, skin irritation assays, and histopathological analyses. NLPFs exhibited a smooth texture with favorable tensile strength and moisture absorption capabilities. Niacin demonstrated interaction with the polysaccharide core, rendering the films amorphous. The films displayed slow and sustained drug release, exceptional antioxidant properties, optimal swelling behavior, and viscoelastic characteristics. Furthermore, the films exhibited biocompatibility and non-toxicity towards skin cells. NLPFs emerged as promising carrier systems for the therapeutic transdermal delivery of niacin, effectively mitigating its flushing-associated adverse effects.