Visualization Of Field Research Articles

A validated finite element model for room acoustic treatments with edge absorbers

Porous acoustic absorbers have excellent properties in the low-frequency range when positioned in room edges, therefore they are a common method for reducing low-frequency reverberation. However, standard room acoustic simulation methods such as ray tracing and mirror sources are invalid for low frequencies in general which is a consequence of using geometrical methods, yielding a lack of simulation tools for these so-called edge absorbers. In this article, a validated finite element simulation model is presented, which is able to predict the effect of an edge absorber on the acoustic field. With this model, the interaction mechanisms between room and absorber can be studied by high-resolved acoustic field visualizations in both room and absorber. The finite element model is validated against transfer function data computed from impulse response measurements in a reverberation chamber in style of ISO 354. The absorber made of Basotect® is modeled using the Johnson-Champoux-Allard-Lafarge model, which is fitted to impedance tube measurements using the four-microphone transfer matrix method. It is shown that the finite element simulation model is able to predict the influence of different edge absorber configurations on the measured transfer functions to a high degree of accuracy. The evaluated third-octave band error exhibits deviations of 3.3–4.1 dB computed from third-octave band averaged spectra.

Large-Scale Oceanic Dynamic Field Visualization Based on WebGL

Large-Scale Oceanic Dynamic Field Visualization Based on WebGL

Welding Skill Education Using 3D Digital Welding Helmet with Extreme Wide- field Visualization Technology

Welding Skill Education Using 3D Digital Welding Helmet with Extreme Wide- field Visualization Technology

Advances in the Clinical Application of Trendelenburg Position.

The Trendelenburg position and reverse Trendelenburg position are frequently employed during lower abdominal surgery to achieve optimal surgical field visualization and complete exposure of the operative site, particularly under pneumoperitoneum conditions. However, these positions can have significant impacts on the patient's physiological functions. This article overviews the historical background of Trendelenburg position and reverse Trendelenbury position, their effects on various physiological functions, recent advancements in their clinical applications, and strategies for preventing and managing associated complications.

Fully coupled aero-hydrodynamic analysis of a biomimetic fractal semi-submersible floating offshore wind turbine under wind-wave excitation conditions

With wind energy utilization shifting to the deep sea, floating offshore wind turbines (FOWTs) have huge potential to improve the competitiveness of offshore wind energy generation. However, traditional FOWT systems are often in force imbalance due to the unique swaying characteristics caused by the unfixed foundation and high center of mass of the platform. Therefore, a novel bionic semi-submersible floating platform based on Victoria Amazonia (with random fractal structure) is proposed to increase the hydrodynamic stability of FOWT. A regular fractal structure with similar number of perforations and perforated area is also implemented to verify the effectiveness of the bionic FOWT. In this study, the unsteady computational fluid dynamic approach is adopted to simulate the aerodynamic and hydrodynamic response. More specifically, the dynamic fluid-body interaction module integrated in STAR-CCM+ is employed to establish a FOWT numerical model with rotating blades, tower, and mooring line system. Furthermore, the volume of fluid model in conjunction with the 6-DOF solver was used to efficiently solve the fluid-induced dynamic motion of FOWT in a multi-phase flow composed of air and water. Finally, the fully coupled calculation of the fractal structure FOWT was performed using the established reliable numerical model. The maximum average thrust and power of 736.43 kN and 5294.04 kW are obtained by random fractal FOWT in aerodynamic responses, while in hydrodynamic amplitude responses, the maximum decreases of 19.16% are obtained by both random fractal and regular fractal structures. As for amplitude responses in heave and surge, the random fractal FOWT of 12.91% and 5.05% decreases performs relatively better than the regular one (11.48% and 4.09% decreases). In addition, the visualization of unsteady flow fields and vortices in fractal structures is investigated in detail. Compared with the regular fractal structure, vortices within random fractal structure interact adequately with the pontoon walls, resulting in higher energy absorption effect and stability.

Numerical investigation of characteristics and mechanism of tunnel erosion of loess with coupled CFD and DEM method

Tunnel erosion of loess can cause geological disasters such as landslide and debris flow, as well as threaten the safety of civil engineering structures. Understanding the mechanism and evolution law of tunnel erosion is not only helpful to analyze the occurrence and development of gully erosion, but also conducive to the guidance of engineering practice. Although many scholars have carried out statistical analysis on loess tunnel erosion based on field investigation, quantitative analysis and visualization at the micro level are lacking. Because the combination of computational fluid dynamics (CFD) and discrete element method (DEM) has great advantages in studying the seepage erosion process. This manuscript adopts the CFD-DEM coupling method, and the virtual cement method is used to transform the failure of cemented matrix into the reduction law of bonding strength. The micro mechanism of tunnel erosion of three areas is discussed from the aspects of particle erosion rate, cement evolution and micro mechanical field. The results show that the more the fine particle content is, the greater the cementation is, the stronger the erosion resistance is, the less developed the erosion rate of the particles is, and the dissolution failure rate of the cement is usually earlier than the erosion rate of the particles, and the variation range of the anisotropy of the contact force is also the smallest. However, under high water pressure, their erosion rates are almost synchronous and reach the slow erosion stage quickly. The anisotropic parameters of the contact force of the three samples virtually decreased gradually in the process of erosion, and finally tended to be stable.

The Surgeon Ergonomic Impact of a Tubular-Based Digital Camera to Perform a Seated Posterior Cervical Foraminotomy

Posterior cervical decompression is a common spine procedure that can be performed with the patient in prone or sitting position. The sitting position provides the potential benefits of more facile retraction of surrounding soft tissues, increased operative field and fluoroscopic visualization, and decreased epidural bleeding. However, the surgeon's ergonomics of this positioning can be quite challenging when using the standard operative microscope to perform the procedure and may cause musculoskeletal harm to the surgeon. A sterile digital camera was brought into the field to perform a sitting foraminotomy completed through the tube retractor at both C6-7 and C7-T1 levels. For half of the procedure, a typical neurosurgical operative microscope was brought into the field to evaluate surgeon ergonomics using baseline Rapid Entire Body Assessment (REBA) scores for 2 surgeons of differing stature. The digital camera was inserted onto the tubular retractor, and REBA scores were calculated. With a microscope, the surgeon with taller stature scored a 5 on the initial REBA scale, and the surgeon with shorter stature scored a 6, placing both in the medium-risk category. Once the tubular-based camera was placed, repeated REBA score of both surgeons was 3, placing them in the low-risk category. Using a tubular-based digital camera system, the ergonomics of the surgery are substantially improved. The surgeon can stand closer to the operative field and look directly at a front-facing screen, allowing increased relaxation of the upper extremity and cervical musculature; improving overall ergonomic function.

Preventive sutures in nonischemic laparoscopic partial nephrectomy. Description of S.P. Botkin City Clinical Hospital technique

Background. Radical removal of the tumor while maximizing sparing of the renal function are the main goals of the partial nephrectomy. Shortening of the warm ischemia time is one of the best ways to achieve good functional results of the surgery. Aim. To present our technique of non-ischemic laparoscopic kidney resection with preventive suturing around the tumor.Materials and methods. Before tumor resection, sutures are placed around tumor spaced by 1 cm with moderate tension. Enucleoresection is performed between tumor and preplaced sutures in visually healthy plane. 30 patients underwent this technique.Results. Median tumor size was 3.6 (1.5–7.2) cm. All patients had negative surgical margin. Warm ischemia was needed in 8 (26.7 %) patients with a median time of 9 minutes. Median operative time was 115 (65–185) minutes. There were no intra or postoperative complications. Trifecta was achieved in all patients (100 %).Conclusion. This technique allows to perform the surgery in non-ischemic fashion, decrease bleeding and improve visualization of the resection field and achieve superior oncologic and functional results.

Streamline Selection around Critical Points of 3D Flow Fields by the Multi-View Clustering

When visualizing streamlines around critical points, the complex and diverse characteristics of the flow field and the possible existence of common points or symmetries among streamlines may lead to the failure of conventional geometric or similarity-based selection methods. Therefore, a data-driven streamline selection method around critical points, MvCcp, is proposed. It is a method based on multi-view clustering algorithm. By voxelizing the flow field with different granularity, the location distribution view and the geometric feature view data based on the histogram of their distance fields are generated, and the streamlines are selected by the multi-view clustering algorithm. The qualitative visualization of the 3D flow field around six typical critical points such as HalfCylinder was compared with three other typical selection methods, and the comparison experiments based on quantitative metrics such as MSE, PSNR, SSIM, AAD showed that MvCcp had more excellent and more stable performance in all experimental 3D flow fields.

Near‐Infrared Mechanoluminescence of Cr3+ Doped Gallate Spinel and Magnetoplumbite Smart Materials

AbstractMechanoluminescence (ML), as an optical response to deformation stimuli, shows great potential in high‐end stress sensing, ultrasonic field visualization, and multidimensional anti‐counterfeiting. However, processive practical applications in bio‐medicine are constrained by the discovery of near‐infrared (NIR) ML materials. Unlike lanthanides (Ln3+) with sharp multiplets, two kinds of Cr3+‐doped NIR ML materials, gallate spinel (ZnGa2O4:Cr3+, Zn3Ga2GeO8:Cr3+) and gallate magnetoplumbite (SrGa12O19:Cr3+) are here reported. Owing to the intrinsic cation antisite defects and cation vacancies in the matrix, these materials exhibit bright NIR ML under a relatively low load (20 N). In particular for SrGa12O19:Cr3+ (750 nm, peak; 100 nm, FWHM) with low persistent luminescence (PersL) interference, the ML behavior can be further rejuvenated under UV and sunlight irradiation. SrGa12O19:Cr3+ also shows bright NIR emission under photo‐ and thermo‐stimulation. Owing to their excellent tissue penetration and concealment capability, NIR ML materials show great potential in the fields of bio‐medicine and anti‐counterfeiting.

Анализ геоинформационных технологий в целях изучения визуализации и отображения вертикальных и горизонтальных деформаций поверхности Земли

Information on the movements and stress-strain state of the Earth`s surface and crust is necessary to predict catastrophic geodynamic processes, such as earthquakes, volcanic eruptions, landslides, glacier collapses, karst sinkholes and subsidence of soils in mining areas. The authors summarize the existing experience of applying geoinformation technologies for modeling Earth’s surface deformations; reveal the shortcomings of current software solutions and the approach to their joint use for analyzing these processes. The relevance of using spatial data infrastructure as a source of data on Earth`s surface deformations is noted. Solutions for improvement of Earth`s surface deformations imaging with the help of the three-dimensional vector fields visualization method, presented by the authors in previous surveys, as well as the results of visualization of the Earth`s surface displacements model, demonstrating applicability and operability of the method developed by the authors, are offered. The requirements and the general functional layout of the thematic geographic information system intended for geoinformation modeling of the Earth`s surface deformations and administrative tasks solution are formed.

Visualization Method for Porous Groundwater Seepage Flow Field Based on Particle Flow: Case of Yancheng City in the East Coast of China

Porous groundwater seepage flow field reflects the spatiotemporal dynamic characteristics of porous groundwater movement. The geometric point and vector line methods are the traditionally used visualization methods for groundwater seepage flow field; however, they exhibit difficulty in describing the characteristics and attributes of a seepage flow field. Therefore, a new particle flow method in the field of computer graphics is introduced in this study to visualize seepage flow field, including the storage conditions, transport mechanism, and seepage field properties of porous groundwater. This visualization method is discussed from four aspects: the generation of seed points, the life cycle of particles, the movement velocity of particles, and the formation of particle trajectory and smooth processing. The seepage field of confined aquifer III groundwater expressed via particle flow and the contour of critical groundwater level are superimposed and analyzed in Yancheng City in the east coast of China. Results show that particle flow can be effectively applied to the visualization of groundwater seepage flow field and provide spatial auxiliary decision-making support for the sustainable exploitation of groundwater and the formulation of geological environment protection measures.

A Comparative Analysis with Exoscope and Optical Microscope for Intraoperative Visualization and Surgical Workflow in 5-Aminolevulinic Acid–Guided Resection of High-Grade Gliomas

The exoscope has been proposed as a valid tool in 5-aminolevulinic acid-guided resection of high-grade gliomas. However, it is not clear if, beyond ergonomics, the exoscope provides a real benefit over the optical microscope (OM). The aim of this study was to compare the exoscope with the OM in terms of surgical visualization and workflow in 5-aminolevulinic acid-guided brain surgery. Surgical videos of patients diagnosed with histopathologically confirmed, Shinoda stage I, high-grade gliomas who underwent surgery in from January to April 2022 were studied. Visualization under a 5-aminolevulinic acid blue filter for vessels, parenchyma, surgical instruments, and fluorescence was categorized for both superficial and deep fields. The following data were also recorded: median number of switches between white light and blue filter, average duration per switch, and amount of work under blue filter. There were 5 surgeries performed under OM guidance and 5 performed under exoscope guidance. Under a blue filter, the exoscope was significantly better than the OM in visualizing vessels, parenchyma, and surgical instruments for both superficial and deep surgical fields. The median number of switches between blue and white light was lower compared with the OM. Both median switch duration and percentage of work under the blue filter were superior when using the exoscope. Within the limitations of a preliminary analysis, use of the exoscope in fluorescence-guided surgery for high-grade gliomas provided significant advantages in terms of visualization of the surgical field under a blue filter and linearity of surgical flow.

Modified Polyethylene Foam for Critical Environments.

One of the most important priorities for all countries with property beyond the Arctic Circle and territories located in permafrost areas is the development of special construction technologies and systems. The required conditions are met by insulation systems based on seamless insulation shells made of polyethylene foam. The study of the strength and performance properties of polyethylene foam and its combinability was carried out according to standard methods and using the methods of experimental design and the analytical processing of the results. The change in material properties at negative temperatures was determined based on the results of climatic tests, followed by an evaluation of creep under load. The evaluation of the effectiveness of the design solutions was carried out using special computer programs. It was found that the performance characteristics of products made of polyethylene foam (rolls, mats) meet the requirements for insulation materials used at temperatures down to -60 °C. The resulting material is moderately combustible, which must be taken into account when developing recommendations for its use in insulation systems. A nomogram has been developed that makes it possible to predict the properties of a material and solve formulation problems. Insulation systems were developed, and a visualisation of the thermal fields of the insulation systems of the external walls and ceilings of a building was carried out.

GPU simulation of wake effects at the Horns Rev 1 offshore wind farm using the CFD porous disk wake model

To verify the effectiveness of the GPU simulation of wake effects at a large-scale offshore wind farm, we ran an in-house large-eddy simulation (LES) solver with a CFD porous disk wake model for the Horns Rev 1 wind farm. For this numerical research, we prepared the latest workstation equipped with a Xeon W-2265 CPU and an NVIDIA RTX A6000 GPU. We clarified that the calculation speed of the single GPU of the NVIDIA RTX A6000 is approximately 10 times faster than the calculation speed of the Xeon W-2265. Careful data analysis and visualization of the unsteady turbulent flow fields obtained in the current LES study suggest that the mutual interference of the wakes developed by wind turbines may frequently form a local speed-up region around wind turbines, located on the downstream side of large offshore wind farms.

Self-supervised learning of neighborhood embedding for longitudinal MRI.

In recent years, several deep learning models recommend first to represent Magnetic Resonance Imaging (MRI) as latent features before performing a downstream task of interest (such as classification or regression). The performance of the downstream task generally improves when these latent representations are explicitly associated with factors of interest. For example, we derived such a representation for capturing brain aging by applying self-supervised learning to longitudinal MRIs and then used the resulting encoding to automatically identify diseases accelerating the aging of the brain. We now propose a refinement of this representation by replacing the linear modeling of brain aging with one that is consistent in local neighborhoods in the latent space. Called Longitudinal Neighborhood Embedding (LNE), we derive an encoding so that neighborhoods are age-consistent (i.e., brain MRIs of different subjects with similar brain ages are in close proximity of each other) and progression-consistent, i.e., the latent space is defined by a smooth trajectory field where each trajectory captures changes in brain ages between a pair of MRIs extracted from a longitudinal sequence. To make the problem computationally tractable, we further propose a strategy for mini-batch sampling so that the resulting local neighborhoods accurately approximate the ones that would be defined based on the whole cohort. We evaluate LNE on three different downstream tasks: (1) to predict chronological age from T1-w MRI of 274 healthy subjects participating in a study at SRI International; (2) to distinguish Normal Control (NC) from Alzheimer's Disease (AD) and stable Mild Cognitive Impairment (sMCI) from progressive Mild Cognitive Impairment (pMCI) based on T1-w MRI of 632 participants of the Alzheimer's Disease Neuroimaging Initiative (ADNI); and (3) to distinguish no-to-low from moderate-to-heavy alcohol drinkers based on fractional anisotropy derived from diffusion tensor MRIs of 764 adolescents recruited by the National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA). Across the three data sets, the visualization of the smooth trajectory vector fields and superior accuracy on downstream tasks demonstrate the strength of the proposed method over existing self-supervised methods in extracting information related to brain aging, which could help study the impact of substance use and neurodegenerative disorders. The code is available at https://github.com/ouyangjiahong/longitudinal-neighbourhood-embedding.

Visualization of the external flow field during a vented explosion for hydrogen-air mixtures: Effects of hydrogen concentrations and vent areas

To study the effects of hydrogen concentrations and vent areas on the vented hydrogen-air explosion, series of experiments were performed in a cylindrical tube under the conditions of 1 atm and 10 ℃. The pressure oscillation frequency is proportional to the hydrogen concentration, while the Helmholtz oscillation disappeared gradually with the increase of Kv. The position inside the container which was farther away from the vent cover would experience the higher dynamic loading. The volume concentration of the hydrogen at the external field (cExt) was always lower than the initial hydrogen concentration, that increased with the increase of the initial concentration, while it was zero at some concentrations with the increase of Kv. The external flame velocity of rich fuel was always larger than that of lean fuel. The deflagration to detonation (DDT) in the outer field was easier to achieve for the concentration near to 50 vol% and for lower Kv. The secondary explosion wave (PExt) increased firstly and then decreased with the increase of hydrogen concentration, which decreased with the increase of Kv in general. The maximum surface temperature rose with the increase of concentration and dropped with the increase of Kv in general. The high-temperature field was closer to the vent for lower concentration and higher Kv.

Minilaparoscopic CLIPLESS Cholecystectomy: Tips, Tricks and Advanced Maneuvers.

As the world sought the 'Holy Grail' of scarless surgery, minimizing access seemed to be the natural path to follow, and minilaparoscopy (MINI) was considered to be a natural advancement of standard laparoscopy. It aims at minimizing surgical trauma by further reducing the diameter of standard instruments, without compromising range of motion, triangulation or safety. Several different terms have been coined to address this sophisticated reduced-port technique, which is characterized by the use of instruments 3 mm or less in diameter: acuscopic surgery, minilaparoscopy, needlescopic surgery and microlaparoscopy. The early adoption of MINI was mostly inhibited by the limitations of first-generation instruments, especially with respect to functionality, cost and durability. Furthermore, mini cholecystectomy demanded the use of mini optics, which suffered from poor imaging quality and a short lifetime of the scopes. Newer-generation mini instruments have mitigated these issues through the use of improved effector tips, better insulation, strength and durability, and superior optics. During the early MINI years, surgeons clipped most structures, but sturdy mini clip appliers were either unavailable or did not hold the requisite-size clips. Clipping with MINI required the use of a standard clip applier and the scope had to be changed several times during a procedure, making MINI not only more complicated but also boring and time-consuming. The development and popularization of the clipless technique allowed the surgeon to get free from the expensive and cumbersome minilaparoscopic clip appliers, and replace clips with knots. The marked improvements in instrumentation and the development of the clipless technique have occurred simultaneously with the development of NOTES, LESS and Robotic surgery, which may have contributed to a greater push towards MINI. MINI has been proven to offer more than just better cosmesis. Other advantages include better visualization of the surgical field and, with the development of precisely engineered low-friction trocars, which enhance surgical precision during dynamic and delicate tasks (knotting and suturing small structures), less stress and higher efficiency, which makes the procedure easier to perform. Furthermore, transmission of electro cautery through mini instruments has led to less lateral spread of electric current and subsequent less tissue trauma. For more than 20 years, our team has successfully used minilaparoscopy. Even with the rising popularity of robotic surgery, which still uses 8 mm instruments, minilaparoscopy remains an attractive option that is far from becoming obsolete.

Efficacy of oral diltiazem on the intraoperative bleeding in functional endoscopic sinus surgery

BackgroundThis study aimed to evaluate the effect of oral diltiazem premedication on blood loss during functional endoscopic sinus surgery (FESS). Study designRandomized, controlled, double-blind study. SettingsUniversity Hospital. PatientsThe study included forty patients aged 18-60 years, with an ASA grade of I-II, scheduled for FESS. InterventionsPatients were randomized into two groups. Group I (n = 20) received preoperative oral diltiazem tablets, and Group II (n=20) received a placebo. MeasurementsThe primary outcome was intraoperative blood loss (total and rate of loss). The secondary outcomes were the surgical field score and hemodynamic parameters. ResultsThe rate of blood loss was significantly lower in group I than in group II (P = 0.023). The surgical field was better in group I than in group II (P < 0.001). No hemodynamic adverse effects were reported in both groups . ConclusionOral diltiazem premedication can improve intraoperative surgical field visualization in functional endoscopic sinus surgeries without any hemodynamic adverse effects.

Ultrafast visualization of an electric field under the Lorentz transformation

In special relativity, four-vectors, such as space–time, energy–momentum and electromagnetic potential vectors, follow the Lorentz transformation. The transformations of space–time and energy–momentum vectors have been tested by time dilation and rest mass energy experiments, respectively. However, the Lorentz transformation of electromagnetic potentials has never been directly demonstrated in experiments due to the limitations of the diagnostics. Here we show the spatiotemporal electric-field profiles around a highly energetic electron beam with a subpicosecond temporal resolution obtained by a terahertz technique based on electro-optic sampling. We observe the Coulomb field contraction in the propagation direction of the beam under the Lorentz transformation. After passing the beam through a metallic plate, we investigate the birth of the Coulomb field around it and follow the spatiotemporal evolution of the spherical wavefront, which is derived by the Liénard–Wiechert potentials. The measured electric-field profile in the far propagation distance is experimentally confirmed to coincide with the calculation of the Liénard–Wiechert potentials and the Lorentz transformation. Our ultrafast measurement of a spatiotemporal relativistic electric field provides both additional experimental evidence of special relativity and a platform for detailed experimental research of energetic charged particle beams and electromagnetic radiation physics.