3D Profile Research Articles

Predicting capillary vessel network hemodynamics in silico by machine learning.

Blood velocity and red blood cell (RBC) distribution profiles in a capillary vessel cross-section in the microcirculation are generally complex and do not follow Poiseuille's parabolic or uniform pattern. Existing imaging techniques used to map large microvascular networks in vivo do not allow a direct measurement of full 3D velocity and RBC concentration profiles, although such information is needed for accurate evaluation of the physiological variables, such as the wall shear stress (WSS) and near-wall cell-free layer (CFL), that play critical roles in blood flow regulation, disease progression, angiogenesis, and hemostasis. Theoretical network flow models, often used for hemodynamic predictions in experimentally acquired images of the microvascular network, cannot provide the full 3D profiles either. In contrast, such information can be readily obtained from high-fidelity computational models that treat blood as a suspension of deformable RBCs. These models, however, are computationally expensive and not feasible for extension to the microvascular network at large spatial scales up to an organ level. To overcome such limitations, here we present machine learning (ML) models that bypass such expensive computations but provide highly accurate and full 3D profiles of the blood velocity, RBC concentration, WSS, and CFL in every vessel in the microvascular network. The ML models, which are based on artificial neural networks and convolution-based U-net models, predict hemodynamic quantities that compare very well against the true data but reduce the prediction time by several orders. This study therefore paves the way for ML to make detailed and accurate hemodynamic predictions in spatially large microvascular networks at an organ-scale.

Effect of Speed and Number of Sliding Cycles on the Film Formation Behavior of Fluorine-Based Grease

Grease, a type of lubricant, finds applications in various mechanical components due to advantages such as shape stability and sealing. However, grease is classified as a non-Newtonian fluid, and its film formation behavior is not fully understood to date due to variations in the mechanism related to the film formation behavior of grease based on factors like the base oil, bleed oil, thickener, and additives. In this study, the film formation behavior of fluorine-based grease was analyzed through the 3D profile of the grease after a friction test. In particular, the film formation behavior of the grease during sliding motion was analyzed. The experimental equipment used was a reciprocating-motion-type experimental equipment. Variations in the 3D profile were observed based on the speed and the cycle, indicating differences in the film formation behavior corresponding to changes in viscosity. In contrast to numerous studies that have observed the film formation behavior of grease under rolling motion, investigating the film formation behavior during the initial cycles of sliding motion will provide a profound understanding of the grease’s film formation process.

Assessing global beryllium erosion via tomographic reconstruction of 3D beryllium emission profiles in ITER

A new method for estimating the global erosion of beryllium (Be) in ITER is proposed. The method uses ray tracing-aided tomography to reconstruct the three-dimensional (3D) profile of beryllium visible-light emissivity in boundary plasma from images captured with filtered cameras of VIS/IR wide angle viewing system, H-alpha (and Visible) Spectroscopy diagnostics and signals collected with divertor impurity monitor. The light reflected into the detectors from metallic plasma-facing components (PFCs) is filtered out in the process. The reconstructed Be emissivity is then used to assess the Be influx density distribution along all Be PFCs by integrating the product of the emissivity and the S/XB coefficient along the normal to the PFC surface. The accuracy of this method is evaluated by a comparison with synthetic emissivity data produced by recent simulation of global Be erosion and migration in ITER using the ERO2.0 code. The impact of the uncertainty of PFC light reflection properties on the error in reconstructing the 3D Be emissivity profile and Be influx density is analyzed. The method allows to recover with good accuracy the Be influx density in plasma-wetted areas under the conditions of H-mode fusion power operation with high plasma density in far scrape-off layer (SOL). Under the conditions of lower far-SOL plasma density and L-mode operation, only the total Be influx integrated over the area of the first wall panels with relatively high Be erosion can be reconstructed with a high accuracy. It is shown that neglecting the effects of light reflection may lead to a twofold overestimation of the total Be influx.

Adaptive multi-point flexible-bending technology for improving the quality of profile using discrete dies driven by snake-shaped motion mechanism

Based on the application of snake-spine-like structures, this paper proposes a roller-type multi-point flexible 3D profile bending process with snake-spine-like structures (Flexible stretch-bending with roller dies - driven by snake-like mechanism, FSBRD-S), and establishes a finite element model. Taking the L-shaped cross-section profile as the research object, different working modes and contact modes are defined to study their impact on crease defects during the vertical bending step, and the new structure is designed to improve the forming quality of the products' surface. The research results show that changing the contact mode leads to a change in the relative angle between the die and the billet. In the process of larger angle vertical bending, the FSBRD-S process can effectively reduce the crease defects generated by the traditional FSBRD process, especially in the area near the clamp. Furthermore, this article proposes the FSBRD-S shape-adjusting technology, which allows for adjustments to the FSBRD-S process based on actual needs, to obtain products with different surface qualities.

Risk indicators for gingival recession in the esthetic zone: A cross-sectional clinical, tomographic, and ultrasonographic study.

To evaluate the risk indicators associated with midfacial gingival recessions (GR) in the natural dentition esthetic regions. Cone-beam computed tomography (CBCT) results of thirty-seven subjects presenting with 268 eligible teeth were included in the cross-sectional study. Clinical measurements included presence/absence of midfacial GR; the depth of the midfacial, mesial, and distal gingival recession; the recession type (RT); keratinized tissue width (KT); and attached gingiva width (AG). Questionnaires were utilized to capture patient-reported esthetics and dental hypersensitivity for each study tooth. Buccal bone dehiscence (cBBD) and buccal bone thickness (cBBT) were measured on the CBCT scans. High-frequency ultrasonography was performed to assess gingival thickness (GT) and buccal bone dehiscence (uBBD). Intraoral optical scanning was obtained to quantify the buccolingual position of each study site (3D profile analysis). Multilevel logistic regression analyses with generalized estimation equations were performed to assess the factors associated with the conditions of interest. The presence of midfacial GR was significantly associated with the history of periodontal treatment for pocket reduction (OR 7.99, p=0.006), KT (OR 0.62, p<0.001), cBBD (OR 2.30, p=0.015), GT 1.5mm from the gingival margin (OR 0.18, p=0.04) and 3D profile 1mm from the gingival margin (OR 1.04, p=0.001). The depth of midfacial GR was significantly correlated to previous history of periodontal treatment (OR 0.96, p=0.001), KT (OR -0.18, p<0.001), presence of bone fenestration (OR 0.24, p=0.044), and cBBD (OR 0.43, p<0.001). The depth of midfacial GR was also the only factor associated with patient-reported esthetics (OR -3.38, p=0.022), while KT (OR 0.77, p=0.018) and AG (OR 0.82, p=0.047) were significantly correlated with patient-reported dental hypersensitivity. Several risk indicators of midfacial and interproximal GR in the esthetic region were identified. The use of imaging technologies allowed for detection of parameters associated with the conditions of interest, and, therefore, their incorporation in future clinical studies is advocated. Ultrasonography could be preferred over CBCT for a noninvasive assessment of periodontal phenotype.

Deformation behaviors of defective aluminum honeycomb sandwich panels subjected to in-panel compressive loading: An experimental study with mirror-assisted multi-view DIC

Honeycomb sandwich panels have been extensively utilized in the aerospace and automotive industries for their prominent advantages of energy absorption, high strength and tailorable anisotropic mechanical properties. Nevertheless, the common presence of local core-to-skin disbonding poses an urgent need to understand the mechanical behaviors of defective honeycomb sandwich panels. The present work investigates the deformation behaviors and evolutions of aluminum honeycomb sandwich panels with varying sizes of circular artificial core-to-skin disbonding defects using mirror-assisted multi-view digital image correlation (MV-DIC). Based on the 3D profiles and dual-surface deformation fields obtained with mirror-assisted MV-DIC, it is revealed that disbonding defects induced local surface undulations with severe local strain concentrations and determined the mode of gradual bending and buckling. Defects with a diameter below 20 mm induced minor local surface undulations and slight decreases in buckling load. When the diameters of defects reach 30 mm, extensive surface convex deformation occurs and the buckling load decreases by 23 %. The results validate mirror-assisted MV-DIC as a cost-effective and practical technique for characterizing dual-surface 3D deformation of sheet composite materials and structures.

Tribological Behavior and Mechanism of Surface-Modified Mullite as Polyurea Grease Additive

Abstract The excellent tribological performance of nanoparticles as additives in lubricating greases has attracted widespread attention. In this study, a silane coupling agent (KH550) was used to chemically modify nanoscale mullite (composed of Al2O3 and SiO2), and the modified nano-KH-mullite was dispersed as an additive in polyurea grease at different ratios (0.01, 0.05, 0.07, 0.1, and 0.3 wt%). The friction and wear performance of the compound polyurea greases were evaluated using a four-ball friction tester. Professional instruments will be utilized to analyze the micro-morphology, 3D profile, elemental content, and valence state of the worn surface, aiming to investigate the lubrication and antiwear mechanism of the nano-KH-mullite additive. The results indicate that nano-mullite effectively improves the antiwear and antifriction performance of the polyurea grease. When the additional content is 0.05 wt%, the friction coefficient (COF) and the wear scar diameter (WSD) are reduced by approximately 19.97% and 11.1%, respectively, and the roughness of the worn surface is also reduced. The excellent tribological performance of the composite grease is attributed not only to the good dispersibility of KH-mullite but also to its ability to promote the formation of a composite lubrication film on the friction pair surface. The component KH-Al2O3 in the KH-mullite can fill and repair scratches and grooves on the worn surface, while the other component KH-SiO2 can bear the load and convert the friction mode to rolling friction.

Experimental investigation of 3D taper profile machining of SS304 using WEDM

ABSTRACT Wire electrical discharge machining (WEDM) is an outstanding variety of EDM processes in which the tool is a wire electrode. The medical, electronics, tool, and die industries use stainless steel 304 (SS304). However, there are traditionally many complications that manufacturers face, while machining SS304. Also, the creation of 3D shapes using WEDM is challenging. Due to difficulties in normal machining and producing 3D profiles using conventional machining of SS304, this research aims to utilize the application of WEDM for creating complex shapes or products with top as square and bottom as rectangular shape to get a rectangular frustum. A ϕ 0.25 mm brass wire was used, and experiments were conducted as per L9 array. Further, the determination of the best process parameter (Ton, Toff, Voltage, current) combination for achieving the highest MRR, hardness, and minimal surface roughness (Ra) and kerf with analysis of machined surfaces using an SEM microstructure image was tried. The results indicated that MRR and Ra values varied from 7.05 to 47.29 mm3/min and 1.251 to 2.019 µm, respectively. Furthermore, the kerf ranged from 0.294 to 0.475 mm and hardness started at 164 to 233 HV. To optimize WEDM results Grey relational analysis (GRA) was utilized.

Preparation of PVDF/PVP blend polymer nanofiber films and application on screen-printed flexible electrodes

The preparation of three electrodes (working electrode, counter electrode, reference electrode) on soft, deformable, and breathable film substrates with good adhesion is a novel approach for the development of wearable devices for plants. In this study, the adsorption energy of carbon paste, graphite, and a polymer was calculated via molecular dynamics simulations, and the optimal polymer ratio was selected for the preparation of nanofiber films. Electrospinning technology was used to prepare a breathable ultrathin polymer film, which was used as a flexible substrate for three electrodes, and a conductive carbon paste was patterned on the nanofiber film substrate by screen printing. The properties of the composite nanofiber membrane substrate and flexible screen-printing electrode were studied by scanning electron microscopy (SEM), infrared (IR) spectroscopy, X-ray diffraction (XRD), 3D profile scanning, and electrochemical experiments. The combination of electrospinning technology and screen-printing technology is a new path for the preparation of nondestructive and wearable detection devices.

Influence of facial width on the perception of lip protrusion and its differences between profile and 3-dimensional video clip

This study evaluated the influence of facial width on the perception of lip protrusion and investigated the concordance between 2-dimensional (2D) profile images and 3-dimensional (3D) video clips in assessing lip protrusion. An Asian female standard head model was created using 3D modeling software. Eight head models were constructed by modifying the standard head model in terms of facial width (broad, neutral, and slim) and lip protrusion (retrusive, straight, and protrusive). Overall, 97 Asian raters rated the lip protrusion from the 2D profiles and 3D rotation video clips of the 9 models. No significant differences were found in the perception of lip protrusion in terms of sex, age, or occupation. Compared with the 2D profiles, the 3D video clips were rated as more protrusive in 8 of the 9 head models, with the retrusive broad, retrusive neutral, straight broad, and straight slim faces showing statistical significance (P<0.01). The rating is significantly higher in slim faces than in broad faces across the 3 groups of 2D profiles (P<0.01). For 3D video clips, the rating was higher in slim faces than in broad faces in all 3 groups, whereas differences were significant in the straight and protrusive groups only (P<0.01). In this study, 3D video clips were more sensitive to the perception of lip protrusion than were 2D profiles to some extent. The lips were rated relatively more protrusive in a slim face than in a broad face. Therefore, the relationship between facial width and lip protrusion should be considered in orthodontic treatment goals and treatment plans.

3D profiling in a laser micromachining station using dual-comb LiDAR

We present a coaxial dual-comb LiDAR integrated into a laser micromachining station, enabling in-situ 3D profiling of machined parts with sub-micrometer axial precision, offering a cost-effective solution with high precision capability.

A machine learning method to infer clusters of galaxies mass radial profiles from mock Sunyaev-Zel’dovich maps with The Three Hundred clusters

Our study introduces a new machine learning algorithm for estimating 3D cumulative radial profiles of total and gas mass in galaxy clusters from thermal Sunyaev-Zel’dovich (SZ) effect maps. We generate mock images from 2522 simulated clusters, employing an autoencoder and random forest in our approach. Notably, our model makes no prior assumptions about hydrostatic equilibrium. Our results indicate that the model successfully reconstructs unbiased total and gas mass profiles, with a scatter of approximately 10%. We analyse clusters in various dynamical states and mass ranges, finding that our method’s accuracy and precision are consistent. We verify the capabilities of our model by comparing it with the hydrostatic equilibrium technique, showing that it accurately recovers total mass profiles without any bias.

Digital twin approach with minimal sensors for Riser's fatigue-damage estimation

This study proposes riser fatigue monitoring based on digital twin models with a motion sensor attached to the platform and riser. The reference model was a spread-moored Floating Production Storage and Offloading (FPSO) with Steel Lazy-Wave Risers (SLWR). Coupled dynamics simulations under given environmental conditions were performed to generate synthetic sensor signals for digital twin models. Finite-element-based riser digital twin models were then constructed to run with the synthetic sensor inputs. A machine learning algorithm that estimates the 3D current profile along the water column was employed to improve the digital twin models by inputting the estimated current profile as additional loads. The digital twin models with or without the estimated current produce the time histories of behaviors and stresses along the riser, and the corresponding fatigue damage and life were estimated by the rainflow-counting method. The fatigue assessment results demonstrate its feasibility through small errors in fatigue damage.

Light-curing units for composite resin polymerization

Light-curing units for light polymerization of composite resins are important instruments of dental practice, and their proper use has a direct impact on the physical characteristics of the material being illuminated, its biocompatibility, as well as on the overall clinical success and durability of dental composites. Irradiance represents the power of radiation per unit of irradiated surface and should be distinguished from irradiance measured directly at the lamp head, which is called output irradiance or emittance. Also, different areas on the surface of the material can be exposed to different radiation powers, which sometimes significantly deviate from the given average value. The reason for this is the inhomogeneity of the radiation beam. The 3D profile of the light beam gives the most precise information about the quality of radiation to which the material will be exposed. Due to the existence of different photoinitiator systems, the use of devices with a wider emission spectrum that covers a larger range of light wavelengths is often recommended today. An important characteristic of the light-curing unit is its power, but the use of lamps of higher power does not mean a proportional reduction in polymerization time. The quality and maintenance of light sources are certainly one of the important factors that influence the success of restorations.

Research on carbon deposition method and characterization of nozzle in direct injection gasoline engine

Based on Geely JLE-4G18TDB 1.8T gasoline engine stand and optical 3D profile measuring instrument, this paper explores the rapid carbon accumulation process and characterization about carbon deposition of nozzle in a direct injection gasoline engines. By using aging accelerators, cycle conditions and long-term fuel pulse width correction coefficient, rapid carbon accumulation close to actual road conditions is achieved. The carbon accumulation situation of the nozzle was mastered in the state of the engine without stopping, and the carbon accumulation characteristics of the nozzle were characterized by optical means. The volume data, three-dimensional image and carbon volume distribution map of the injector before and after carbon deposition were obtained under the condition that the carbon in the surface area of the injector was not destroyed, which played an important role in the evaluation of the gasoline purifier and purifier synergist.

Hyperspectral imaging and TRI3DYN simulation study of physical sputtering from a fuzzy surface

The influence of a fuzzy surface on the physical sputtering of Mo in He plasmas has been studied with hyperspectral imaging (HSI) measurements and simulations that couple the TRI3DYN code with an impurity transport code. The 2D profiles of the Mo I line emission intensity from HSI images reveal that the sputtering yield, Y, is reduced to ∼40 % of the smooth-surface value due to the presence of a fuzz layer, while the angular distribution of the sputtered Mo atoms might not change significantly. The simulations reproduce the Y reduction successfully, but indicate that fuzz causes an increase in the small-angle distribution of sputtered atoms. However, the increase is too small to produce an observable change in the Mo I emission profiles. A simple analytical model that assumes a single collision mean free path for a fuzz layer and considers only the primary sputtering events qualitatively reproduces the Y reduction and the small-angle distribution enhancement, explaining the geometrical effect of fuzz on physical sputtering.

Encoded Magnetization for Programmable Soft Miniature Machines by Covalent Assembly of Modularly Coupled Microgels

AbstractThe bottom‐up assembly of premagnetized microgels offers remarkable flexibility in programmability, material selection, and complexity for fabricating programmable magnetic soft machines with discrete 3D magnetization profiles. However, the current microgel bonding encounters challenges due to the utilization of adhesives for attachment, biocompatibility for in vivo applications, and the need for elevated temperature for self‐healing materials. Here, an approach is presented that leverages N‐hydroxysuccinimide ester‐activated sodium alginate (SA‐NHS) and chitosan (CS) to form modular gels for on‐demand assembly through covalent bonding, yielding a tough and durable interface. Photolithography‐based patterning and magnetic maneuverability are imparted by introducing poly(ethylene glycol) diacrylate and ferromagnetic particles into SA‐NHS or CS, resulting in the creation of modularized magnetic or nonmagnetic microgels. Different magnetization profiles of the modular microgel can be achieved by magnetizing the ferromagnetic particles inside the microgel. To prove the versatility of the proposed method, several programmable magnetic soft machines are developed for various application scenarios, including heterogeneous cell‐laden hydrogel assemblies, multisegmented magnetic soft swimmers, programmable magnetic switches for electric circuits, and magnetically triggered release from drug‐encapsulated magnetic capsules. This proposed approach holds great potential to engineer highly intricate and hierarchical architectures, enhancing the functionality, versatility, and adaptability of programmable soft machines.

Research on petrophysical properties and porosity evolution of fractured coal mass under cyclic impact for coalbed methane exploitation

In the process of coalbed methane (CBM) extraction, coal seam penetration modification is frequently subjected to several cycle impact due to drilling-blasting method and deflagration fracturing method. Therefore, the split Hopkinson pressure bar (SHPB) was utilized to investigate the impact cycle effect and confining pressure effect on dynamic behavior of coal. Furthermore, the low-field nuclear magnetic resonance (NMR) was utilized to evaluate the modification of multiscale pore before and after 5 cycles impacts. Finally, the 3D profile scanner was utilized to quantify fracture surfaces and assess fracture roughness variation. The results showed that there existed the 6 MPa critical confining pressure that altered the dynamic mechanical properties of coal. Due to the combined effect of the confining pressure and cycle impact, the damage variable based on the energy method showed a log-normal distribution. With increasing strain rate, the micropores evolved into mesopores and macropores. There was a critical strain rate that caused the ratio of effective porosity to total porosity to shift from increasing to decreasing. Furthermore, the fracture roughness was shown to be positively correlated with the ratio and negatively correlated with seepage fractal dimension. The research findings can provide theoretical guidance for the safer and more efficient CBM exploitation.

High accuracy calibration method for multi-line structured light three-dimensional scanning measurement system based on grating diffraction.

Multi-line structured light three-dimensional (3D) scanning measurement system enables to obtain the richer 3D profile data of the object simultaneously during one frame, ensuring high accuracy while structured light is deformed for the modulation by the object. Nevertheless, current calibration methods cannot fully take advantage of its high precision. In this paper, a fast and high-accuracy 3D measurement system based on multi-line lasers with a spatially precise structure via integrating a diffraction grating was proposed. This helps achieve precise calibration results of the light planes by introducing spatial constraint relations of the diffractive light, thus improving measurement accuracy. The operating principle and the workflow of the proposed system were described in detail. The measurement accuracy of the developed prototype was verified through contrastive experiments. At a working distance of 400 mm, the results show that the root mean square error (RMSE) of the proposed system is 0.083 mm, which is improved by 37.6% compared to the traditional calibration method of light planes for the ranging system. The system utilizing a grating that facilitates the integration of the device has great application value.

Bound Ca2+ moves faster and farther from single open channels than free Ca2.

A concept of Ca2+ nanodomains established in the cytoplasm after opening single-calcium channels helps mechanistically understand the physiological mechanisms of Ca2+ signaling. It predicts standing gradients of cytoplasmic free Ca2+ around single channels in the plasma membrane. The fate of bound Ca2+ attracted much less attention. This study aimed to examine the profiles of Ca2+ bound to low-mobility buffers such as bulky Ca2+-binding proteins. The solution of non-linear PDEs for an immobile buffer predicts fast decay of free [Ca2+] from the channel lumen and the traveling wave for bound Ca2+. For low-mobility buffers like calmodulin, the calculated profiles of free and bound Ca2+ are similar. Theoretical predictions are tested by imaging 1D profiles of Ca2+ bound to low-mobility fluo-4-dextran. The traveling waves of bound Ca2+ are observed that develop during the opening of single channels. The findings tempt to propose that Ca2+ signaling may not be solely related by the absolute free [Ca2+] at the sensor location, which is extremely localized, but determined by the time when a wave of bound Ca2+ reaches a threshold needed for sensor activation.