Linear Shape Research Articles

Exploring Acoustic Detection of α-Synuclein Fibrils.

Over the past decades, the incidence of Parkinson's disease (PD) cases has doubled in industrialized countries. While patients over 70years old still represent more than half of the cases, the disease is increasingly affecting younger individuals. Environmental factors have been implicated, such as the effects of certain pesticides or chemicals on neurons, such as rotenone or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Researchers have also demonstrated the influence of genetic mutations in younger patients. A-synuclein is a protein encoded by the SNCA gene, known to undergo various mutations in hereditary cases of PD. These mutations alter the composition and spatial arrangements of α-synuclein. The proteins, originally of linear shape, aggregate during the progression of PD, forming fibrillary structures that propagate through brain tissues. Among the physical therapies investigated for treating α-synuclein aggregation, ultrasonic waves, capable of altering protein and cell behaviors, have recently been used to disrupt α-synuclein fibrils within tissues in cellular and animal models, with the hope of developing treatments based on ultrasound properties. However, detecting fibrils typically requires invasive and non-biocompatible chemical compounds or cumbersome machinery. In this study, our acoustic experimental setup allowed us to investigate the response of α-synuclein to ultrasound perturbations. By capturing the transmitted wave across proteins over a frequency range 10kHz to 10MHz, no ultrasound signature indicating the presence of proteins was observed.Significance Statement: The results report there is no ultrasound signature of the presence of α-synuclein fibrils, from 10kHz to 10MHz.

An isolated organ feasibility study of deformable self-assembled magnetic anastomosis rings for esophageal stenosis anastomosis

Magnetic compression anastomosis (MCA) for esophageal stenosis requires the insertion of magnets through two channels, transoral and transgastrostomy. Herein, we designed a Y-Z deformable self-assembled magnetic anastomosis ring (Y-Z DSAMAR) for esophageal stricture anastomosis through the transoral passage only. We introduce a Y-Z DSAMAR and verify its feasibility for single-access esophageal stenosis anastomosis in isolated organs. We procured esophagi from 10 pigs. Next, we ligated the middle part of these esophagi with 7 − 0 silk to prepare an esophageal stenosis model. The linear Y-Z DSAMAR completed the deformation self-assembly and transitioned from its initial linear shape to a circular one while passing through the esophageal stenosis. The operation time, the success rate of the deformation self-assembly of Y-Z DSAMARs, and the successful MCA for esophageal stenosis were recorded. We successfully obtained a trapezoidal magnetic unit. Ten such magnetic units can self-assemble into a ring after the hard guide wire is withdrawn. The success rates for both self-assembly deformation and esophageal stenosis anastomosis were 93.33%, while that for esophageal stenosis anastomosis with successful deformation was 100%. Y-Z DSAMARs exhibit remarkable deformation-controllable characteristics. Further optimization of the operational procedure and verification through animal experiments are needed before they can be clinically applied.

Machine Vision-Based Real-Time Monitoring of Bridge Incremental Launching Method.

With the wide application of the incremental launching method in bridges, the demand for real-time monitoring of launching displacement during bridge incremental launching construction has emerged. In this paper, we propose a machine vision-based real-time monitoring method for the forward displacement and lateral offset of bridge incremental launching in which the linear shape of the bottom surface of the girder is a straight line. The method designs a kind of cross target, and realizes efficient detection, recognition, and tracking of multiple targets during the dynamic process of beam incremental launching by training a YOLOv5 target detection model and a DeepSORT multi-target tracking model. Then, based on the convex packet detection and K-means clustering algorithm, the pixel coordinates of the center point of each target are calculated, and the position change of the beam is monitored according to the change in the center-point coordinates of the targets. The feasibility and effectiveness of the proposed method are verified by comparing the accuracy of the total station and the method through laboratory simulation tests and on-site real-bridge testing.

Static analysis of wind blades based on weight loads to the gravitation and the centrifugal forces Using Finite Element

Static analysis of wind turbine blades that convert kinetic energy using wind to electrical power has been analyzed using Ansys model. The geometry was imported in ANSYS workbench 2020R1, where the material was changed to Epoxy E-Glass Wet. The mesh independence that occurred at 800 and 600 element sizes and an element size of 800 was chosen for subsequent static analysis. The static analysis shows that the total deformation and von Mises stress of the wind turbine blade was improved at both the vertical position and the horizontal position by 40.0% and 38.61%, respectively. Besides, the static analysis showed an almost linear mode shape increased from mode lines. Nevertheless, Campbell's diagram showed that resonance vibration occurred at an amplitude of 5.5x106Pa with a corresponding frequency of 5Hz, which gave a rotational speed of 262.4x106 rpm. This shows that the impulse force is better applied in wind turbine blade transient analysis at a lower von Mises stress to attain a quicker damping response steady-state, which favors wind turbine blade analysis. Overall, the wind turbine blade is better designed at a vertical position to allow better deformation stress at a static position. Conversely, the von Mises stress showed 44.64% and 38.61% at horizontal and vertical positions. This also agrees with static total deformation, since stress is better managed at a lower percentage range.

Research on the Construction Mechanics and Stability Control Technology of Expressway Tunnel Based on Numerical Analysis

As an effective structural form, connecting arch tunnel has been widely used in practical engineering because of its smooth linear shape, small footprint and good bridge and tunnel connection. With the increase of domestic traffic volume year by year, the width of the even arch tunnel is gradually changed from two-way four lanes to two-way six lanes. I20 I-steel, spacing 0.75∼1 m, anchor length 3∼4 m, ring spacing 0.5∼1 m, the side ring spacing of the middle wall is 0.75 m, the side ring spacing of the side wall is 1 m, and the shotcrete thickness is 0.25∼0.3 m. The excavation span of a two-way six-lane continuous-arch tunnel is considerable, leading to complex stress characteristics, thereby posing risks to construction safety and structural stability. Following the construction of the initial tunnel, disturbance to the surrounding rock occurs, affecting subsequent excavation phases. The initial support requirements for subsequent excavations are more intricate, with increased internal forces compared to the initial tunnel segment. As the rear tunnel progresses, the surrounding rock near the middle wall shifts towards the rear tunnel, reducing internal forces in the concrete and steel arch frame. However, as the rear tunnel distance increases, concrete stress and axial forces on the middle wall side of the initial tunnel begin to rise. Throughout the construction, the steel arch frame’s internal forces and spray concrete stress on the middle wall side’s arch waist and foot are the highest, making them susceptible to disruption from construction on the opposite side, thus constituting critical tunnel components. Numerical simulations effectively capture surrounding rock and structural stress dynamics during large-span arch tunnel construction. Simulation outcomes align closely with field measurements, particularly in three-dimensional simulations, enhancing construction understanding and management.

An Artificial Neural Network Model for Short-Term Traffic Flow Prediction in Two Lane Highway in Khulna Metropolitan City, Bangladesh

Short-term traffic flow prediction is one of the most significant research topics in traffic engineering. It is instrumental in designing a more modern transport network to manage traffic signals and reduce congestion. Short-term traffic flow is a challenge that a third-world country like Bangladesh is all too familiar with. Like the other cities of Bangladesh, Khulna Metropolitan City is gradually becoming more aware of this situation. The Khulna-Jashore National Highway (N-7), which runs through the city and provides a linear shape, serves as the backbone of the Khulna Metropolitan City traffic flow. This study developed an Artificial Neural Network (ANN) model for the short-term Traffic Flow Prediction on Two-Lane Highway in Khulna Metropolitan City, Bangladesh. Data was collected from March 1, 2021, through June 30, 2021, during 600–900 hours and 1200–1500 hours. Good-quality electronic cameras recorded the vehicles at the full designated length. The regression graphs displayed the network outputs with targets for the training, validation, and test sets. The various speed level parameters for which the fit is reasonable for all data sets, with R values of 0.98426 in each case. The various traffic volume parameters for which the fit is reasonable for all data sets, with R values of 0.96758 in each case. The model's superiority is indicated by its low mean squared error values. This study demonstrated that the neural network has a good prediction effect on specific road traffic flow, which can achieve the goal of short-term prediction and has improved practicability through testing on real traffic data. This study provides an opportunity to provide a suitable alternative for short-term traffic flow forecasting in Khulna Metropolitan City with traffic flow conditions for two-lane undivided highways.

Quantifying NO x Emission Sources in Houston, Texas Using Remote Sensing Aircraft Measurements and Source Apportionment Regression Models.

Air quality managers in areas exceeding air pollution standards are motivated to understand where there are further opportunities to reduce NO x emissions to improve ozone and PM2.5 air quality. In this project, we use a combination of aircraft remote sensing (i.e., GCAS), source apportionment models (i.e., CAMx), and regression models to investigate NO x emissions from individual source-sectors in Houston, TX. In prior work, GCAS column NO2 was shown to be close to the "truth" for validating column NO2 in model simulations. Column NO2 from CAMx was substantially low biased compared to Pandora (-20%) and GCAS measurements (-31%), suggesting an underestimate of local NO x emissions. We applied a flux divergence method to the GCAS and CAMx data to distinguish the linear shape of major highways and identify NO2 underestimates at highway locations. Using a multiple linear regression (MLR) model, we isolated on-road, railyard, and "other" NO x emissions as the likeliest cause of this low bias, and simultaneously identified a potential overestimate of shipping NO x emissions. Based on the MLR, we modified on-road and shipping NO x emissions in a new CAMx simulation and increased the background NO2, and better agreement was found with GCAS measurements: bias improved from -31% to -10% and r2 improved from 0.78 to 0.80. This study outlines how remote sensing data, including fine spatial information from newer geostationary instruments, can be used in concert with chemical transport models to provide actionable information for air quality managers to identify further opportunities to reduce NO x emissions.

Mechanical characterization of large diameter UHMWPE ropes under quasi-static tensile loading: An experimental study

The Large diameter UHMWPEFR (Ultra High Molecular Weight Polyethylene Fiber Rope) are ideal for heavy lifting and slinging, with their mechanical properties and behaviour characterisation are key to the application.Therefore, this study conducts uniaxial tensile tests on a 115 mm diameter rope (FR-115) to investigate its mechanical properties under quasi-static tensile conditions. considering the anisotropic structural characteristics of UHMWPEFR, a method and criteria for eliminating inter-strand gaps and uneven force through pre-tensioning were proposed. Subsequently, tensile tests were carried out to examine the mechanical properties and constitutive relationship of the rope. The experimental results indicate that pre-tensioning can effectively eliminate the influence of non-elastic deformation of the rope, meeting the formal tensioning requirements based on the stability criteria of the rope structure constructed from mechanical and physical parameters. The stress-strain curve of FR-115 shows a linear bilinear shape without a yield segment during the tensioning process, presenting a typical brittle failure mode. The mechanical behavior is closely related to the historical load effects and loading speed, with the rope transitioning from soft and tough to hard and brittle, exhibiting hysteresis. Based on the above analysis, the graded load and time-varying modulus parameter are fixed, and the internal force is more sensitive to the quasi-static tensile velocity; a two-stage principal model is established based on the analysis of curve characteristics and time-dependent correlation, with 50 % MBS(Minimum Break Strength) as the characterization point, and the UHMWPEFR principal relationship in the pre-period is linear-elastic, and the strain-rate effect is taken into account for the dense section, and the rate correlation and nonlinear characteristics of the dense section of the rope can be accurately portrayed with the introduction of Cowper-Symonds.

A biodegradable shape memory polyurethane film as a postoperative anti-adhesion barrier for minimally invasive surgery

Postoperative adhesions commonly form in various tissues, resulting in serious implications and an increased risk of secondary surgery. The application of anti-adhesion films as physical barriers has proven effective in reducing adhesion incidence and severity. However, existing anti-adhesion films require manual deployment during minimally invasive surgery, posing inconvenience and possibility of further injury. To address these limitations, we have developed an intelligent anti-adhesion film based on shape memory polyurethane. In this work, a linear shape memory polyurethane (ISO2-PU), incorporating hexamethylene isocyanate and isosorbitol as hard segments and poly(D, L-lactic acid) macrodiol as soft segments, was fabricated into an anti-adhesion film. The favorable shape memory effect of the ISO2-PU film ensures its convenient delivery and automatic unfolding, as revealed by a simulation experiment for endoscopic surgical implantation. Furthermore, the glass transition temperature (Tg) close to body temperature endows the ISO2-PU film with good mechanical compliance, thus ensuring a reliable fit with the wounded tissue to avoid undesired folding. Finally, in vivo experiments using a rat cecal abdominal wall injury model demonstrated that the combination of reliable fit, appropriate degradation rate, and good cytocompatibility promises the ISO2-PU film with high anti-adhesion efficacy. This work validates the concept of shape memory anti-adhesion barrier and expands future directions for advanced anti-adhesion biomaterials. Statement of significancePostoperative adhesions are a common complication that occurs widely after various surgeries. This work developed an intelligent anti-adhesion film based on a linear shape memory polyurethane (ISO2-PU). This film is featured with remarkable shape memory effect and mechanical compliance at body temperature, appropriate degradability, and good cytocompatibility. These merits ensure convenient delivery and smart unfolding of ISO2-PU film during minimally invasive surgery and favorable postoperative anti-adhesion efficacy. The results validate the concept of shape memory anti-adhesion barrier and paves a way for designing next-generation anti-adhesion biomaterials.

Nanotechnology for thermal comfort and energy efficiency in educational buildings with a simulation and measurement approach in BSh climate

Educational buildings have a large share and impact on urban development. While research shows a significant portion of non-industrial energy consumption in these buildings, obtaining optimal thermal comfort in educational buildings remains one of the main concerns in achieving the grounds to promote students’ best performance and efficiency. Extensive research has been done in this field, however, this research presents a new approach to the diverse use of nanotechnology techniques which improve its properties and components in the buildings, aiming to reduce energy consumption and increase thermal comfort. In this paper, thermal comfort and energy consumption are evaluated in a 12-class elementary school located in Shiraz City. Aeropan and nano-Phase change materials (nano-PCMs) is used in the window glass and walls of the studied case. This evaluation presents the simulation and experimental analysis of thermal comfort (PMV) and energy consumption of three classroom alignments in the school building including the Linear-shape (LS), the Integrated Linear-shape (ILS), and the U-shaped (US) alignment. The simulation was performed using EnergyPlus 9.6 software, while the experimental data was collected using TESTO 425 device. The result of this research shows that after applying nano-PCM and Aeropan techniques in window glass and walls, the US alignment has the highest reduction in energy consumption (monthly average of 11.80%) compared to LS and ILS alignments. This alignment includes an energy consumption reduction of 12.03% in the coldest, and, 11.66% in the hottest day of the year in addition to increasing the monthly average thermal comfort of school by the use of nanomaterials.

Reconfigurable DNA Nanocage for Protein Encapsulation and Regulation.

Creating nanomachines capable of precisely capturing, organizing, and regulating the activity of target biomolecules holds profound significance for advancing nanotechnology and therapeutics. Here, we develop a multistage reconfigurable DNA nanocage that can enclose and modulate proteins through multivalent interactions, activated by specific molecular signals. By strategically designing and manipulating the strut architecture of the DNA nanocages, we can achieve precise control over their reconfiguration among pyramid, square, and linear branch shapes. Additionally, we demonstrated its ability to capture thrombin and effectively inhibit its coagulation activity by incorporating two thrombin-targeting aptamers into the designed arms of the DNA nanocage. The activity of thrombin can be recovered by rearranging the conformation of the DNA nanocage and exposing the protein, thereby activating the coagulation process. This approach enriches the design toolbox for dynamic nanomachines and inspires a new strategy for protein encapsulation and regulation with potential future therapeutic applications.

Riparian plant community structure and assembly processes differed by variations in riverbank curvatures: implications for restoring habitats along the Three Gorges Reservoir

Abstract A meandering riverbank plays a vital role in maintaining natural river ecosystems, providing habitats for riparian vegetation. However, dams have significantly altered riverbank shapes. To restore the riparian ecosystems, it is imperative to understand how different riverbank curvatures influence them. This study aims to uncover the ecological impacts of riverbank curvature on the structure and assembly process of plant communities in the riparian zone of the Yangtze River, regulated by the Three Gorges Dam (TGD) in China. We categorized the riparian zones into four types: cove, lobe, wavy, and linear shapes. We documented the composition and diversity of riparian plant communities. Our findings revealed that wavy and cove riverbanks exhibited greater species diversity (with Shannon-Wiener diversity index values 1.5 times higher) compared to communities along linear riverbanks. Furthermore, the analysis of functional traits indicated that wavy riverbanks promoted the differentiation of plant functional traits, thus enhancing ecosystem functions, with functional dispersion index (FDis) values 1.3 times higher than those of linear riverbanks. Significant variations in the assembly of riparian communities were also observed among different riverbanks, with standardized effect size (SES) values indicating a higher degree of niche differentiation in cove riverbanks (SES = 0.4) compared to linear riverbanks (SES = -0.6). These results highlight the ecological importance of diverse riverbank curvatures in influencing the diversity, structure, and assembly of riparian communities along waterway. In conclusion, this study underscores the necessity of maintaining or restoring various natural morphological curvatures when rehabilitating riparian communities along rivers impacted by human activities.

Association of baseline sleep duration and sleep quality with seizure recurrence in newly treated patients with epilepsy.

Although sleep duration and sleep quality are considered to be significant factors associated with epilepsy and seizure risk, findings are inconsistent, and their joint association remains uncertain. This study aimed to determine independent and joint associations of these two modifiable sleep features with seizure recurrence risk in newly treated patients with epilepsy (PWE). This is a prospective cohort study of newly treated PWE at a comprehensive epilepsy center in northeast China between June 2020 and December 2023. Self-reported sleep duration and sleep quality were collected at baseline. All patients were followed for 12 months for recurrent seizures. Cox proportional hazard regression models were used to estimate the hazard ratios (HRs) of seizure recurrence. Models fitted with restricted cubic spline were conducted to test for linear and nonlinear shapes of each association. A total of 209 patients were included, and 103 experienced seizure recurrence during follow-up. Baseline short sleep was significantly associated with greater risk of seizure recurrence (adjusted HR = 2.282, 95% confidence interval [CI] = 1.436-3.628, p < .001). Sleep duration (h/day) and recurrent seizure risk showed a significant nonlinear U-shaped association, with a nadir at 8 h/day. Baseline poor sleep quality was significantly associated with greater risk of seizure recurrence (adjusted HR = 1.985, 95% CI = 1.321-2.984, p < .001). Pittsburgh Sleep Quality Index score and seizure recurrence risk exhibited a positive linear association. Participants with a combination of poor quality-short sleep showed the highest risk of seizure recurrence (adjusted HR = 3.13, 95% CI = 1.779-5.507, p < .001) compared to the referent good quality-intermediate sleep group. Baseline sleep duration and sleep quality were independently and jointly associated with risk of seizure recurrence in newly treated PWE. Our results point to an important potential role of baseline sleep duration and sleep quality in shaping seizure risk.

Hip contact force pathways in total hip replacement differ between patients and activities of daily living

One of the main causes of implant failure and revision surgery in total hip replacement (THR) is aseptic loosening often caused by the accumulation of wear debris arising between the contact surfaces of the acetabular cup and femoral head during activities of daily living (ADL’s). However, limited information is available regarding the contact force pathways between these two surfaces during specific ADL’s. In this study, through musculoskeletal modelling, we aimed to estimate the orientation of the hip contact force pathway on the acetabular cup. One hundred and thirty-two THR patients underwent motion capture analysis whilst undertaking locomotor and non-locomotor ADL’s. Musculoskeletal simulations were performed to calculate contact force pathways using inverse dynamics analysis. We then qualitatively compared differences in the contact force pathways between patients and between ADL’s. Walking resulted in a typical figure-of-eight pattern, with the peak contact forces occurring in the superior-anterior area of the cup. The non-locomotive activities such as stand up, sit down and squat had a more linear shape, spanning across the superior-posterior quarter of the cup. Our results showed a large inter-patient variability in the shape and location of the contact force pathway.There is a distinct difference in the location and shape of the pathway between locomotor and non-locomotor activities and this could result in different wear accumulations. These results could enhance our understanding why revision rates vary across the population and could inform the development of personalised implant design.

Concave-to-convex curve conversion of fiber cells correlates with Y-shaped suture formation at the poles of the rodent lens

The eye lens contains convexly curved fiber cells that align in concentric layers around the lens anterior-posterior pole axis. For lens fiber differentiation at the equator, cells elongate with their apical and basal tips migrating towards the anterior and posterior poles, respectively. At each pole, the fiber tips meet opposing tips of other fiber cells, to form a suture. Although umbilical or point sutures are observed in fish and birds, line, Y- or star-shaped sutures are detected in other vertebrate lenses. Sutures that do not converge at the point are thought to result from intricate movements of the fiber tips, rather than a straightforward migration along a meridional path. The triggers that give rise to these variations are currently not understood. Our findings revealed that in the mouse embryo, the early-stage lens contains only concave curved fibers, and later, a zone of concave-to-convex curve conversion develops. At this point, a nascent suture in a linear shape appears at the posterior pole and subsequently progresses into a V-shape. This V-shape appears to further develop into a Y-shape as a branch extends from the apex of the V-shape. In lens of zebrafish and Xenopus larvae that form point sutures, this curve-conversion zone is not observed. In lens of adult birds (e.g. zebra finch) that form a point suture, these too also lack a curve-conversion zone. In our previous studies, we demonstrated that murine lens fibers undergoing curve conversion extend membrane protrusions, or lamellipodia, at their basal membranes. In line with this, we did not observe protrusions at the basal tips of fibers in the non-mammalian lenses of zebrafish, Xenopus, and zebra finch in which curve conversion does not occur. We propose that the concave-to-convex conversion in rodent lenses introduces defined paths for fiber cell tips, leading to a more elaborate and complex suture formation, compared to the simple point suture of lower vertebrates.

Effect of heat treatment on the stability of ultrasound-assisted cross-linked myofibrillar protein-stabilized emulsion filler phases via rheology and tribology

This work aimed to reveal the effect of heat treatment on the stability of ultrasound-assisted cross-linked myofibrillar protein-stabilized emulsion and its potential application as a filler phase. The interfacial dilatational rheology, emulsion droplets, linear and nonlinear shear rheological properties, microrheological properties, and tribological properties of emulsion fabricated by the original myofibrillar protein (MP) (NA), crosslinked MP (NAG), and sonication after crosslinked MP (MPGU) were determined at the heat temperature of 40 °C, 60 °C, and 80 °C. Results indicated that heat treatment would affect the stability and processing adaptability of the emulsion. The elasticity and strength of the interfacial film were enhanced with the treated temperature increased from 40 °C to 80 °C, and the MPGU group showed a more linear shape of interfacial Lissajous plot than the other groups even at large amplitudes. Based on the good interfacial properties, the MPGU group had the smaller emulsion droplets with more protein-coated, and the network structure was formed only at 80 °C. For the rheological properties, the lower apparent viscosity, elastic index (EI), and macroscopic viscosity index (MVI) in the MPGU group indicated the formation of a more stable emulsion. Furthermore, the lower closed area of Lissajous curves and friction coefficient for the MPGU group also proved the highest stability and lubrication of the emulsion after heat treatment. Therefore, this study indicated that ultrasound-assisted cross-linked myofibrillar protein-stabilized emulsions had good thermal stability and processing adaptability, which contributed to the fabrication of stable emulsion-filled foods.

Non-Fourier heat and mass transport enhancement by hybrid nanofluid-flow over a non-linearly stretchable surface having variable thickness

This article uses non-classical Fick's law, non-Fourier's law, and conservation laws for mass and thermal transport. The hybrid nanoparticles Cu and Al2O3 are considered. The new correlations among the thermo-physical properties of base fluid, Cu and Al2O3 are coupled with simplified nonlinear mathematical models. The resulting models are solved numerically by the finite element method (FEM). The linear shape functions are chosen for the approximation of residual equations. This approximation leads to a nonlinear algebraic system that is linearized by the Picard scheme. The numerical results are ensured to be grid-independent, and convergence is analyzed. The results are validated, and an excellent agreement is obtained between available benchmarks and current outcomes. Thermal solutal relaxation phenomena are responsible for a significant reduction in the transport of heat and mass in Newtonian fluids. These non-Fourier's and non-classical Fick's laws are capable of capturing thermal and solutal elastic phenomena, respectively. Cu and Al2O3 simultaneously act as good conductors of heat, and their simultaneous dispersion in base fluid results in a significant rise in thermal conductivity. Numerical experiments have shown that the transport of heat can be optimized by simultaneous suspension of Cu and Al2O3.

Lobar collapse: what radiologists need to know

Radiologists have to diagnose lobar collapse routinely, so they should be familiar with the direct and indirect signs of lobar atelectasis and with uncommon findings, for being able to make early diagnosis. Atelectasis can be caused by several mechanisms: by obstruction (due to neoplastic or non-neoplastic causes), by loss of negative pressure in the pleural space and/or by compression of lung parenchyma (e.g., pneumothorax, hydrothorax, and pleural effusion) or by an increase in alveolar surface tension (e.g., acute respiratory distress syndrome and neonatal respiratory distress syndrome). Collapses, moreover, can be observed in several ways. Lobar atelectasis occurs when entire pulmonary lobe is collapsed. Linear atelectasis (previously “plate like” or “band like”) is a local collapse with linear, plate-like or band-like shape which usually parallels the hemidiaphragms. Rounded atelectasis is a consequence of chronic or recurrent pleural effusion, which could be related to asbestos disease, chronic cardiac or renal failure, and thoracic malignancies. It occurs as a rounded mass abutting the pleura with adjacent pleural thickening. Collapsed lobes can assume quite limited forms and radiologists require familiarity with radiographic findings for helping clinical physician in the diagnostic process.

Experimental study on the effect of longitudinal ventilation on spill fire characteristics in sloped tunnels

A series of spill fire tests were carried out in a reduced-scale tunnel (6 m × 0.6 m × 0.45 m), considering different discharge rates (60–140 ml/min), ventilation rates (0∼1.26 m/s), and tunnel slopes (3 %, 5 %, 7 %). Some crucial characteristic parameters during the quasi-steady combustion stage of tunnel spill fires were analyzed, including the diffusion shape of the liquid fuel, mass burning rate per unit area, flame morphology and plume temperature, and the critical ventilation velocity. The results show that as the tunnel slope increases, the diffusion shape of the liquid fuel transitions from circular to an ellipse shape and then to rectangular or linear shape. Moreover, the mass burning rate per unit area decreases with increasing ventilation rates at low ventilation (V < 0.5 m/s), while it remains almost constant at high ventilation rates (V ≥ 0.5 m/s). This could be attributed to variations in flame tilt behavior under different ventilation conditions. Predictive models for the flame tilt angle and the vertical temperature distribution of tunnel spill fires under the effect of ventilation were further established and verified. Furthermore, the critical ventilation velocity of tunnel spill fires remains essentially unchanged as the discharge rate (or fire source power) increases. This phenomenon was explained by analyzing the resistance of the spill fire plume and the buoyancy generated by the smoke temperature. This work could serve as a critical reference for assessing disaster risks and executing emergency rescue operations during tunnel spill fires.

Some Unfamiliar Structural Stability Aspects of Unsymmetric Laminated Composite Plates.

It is widely recognized that certain structures, when subjected to static compression, may exhibit a bifurcation point, leading to the potential occurrence of a secondary equilibrium path. Also, there is a tendency of deflection increment without a bifurcation point to occur for imperfect structures. In this paper, some relatively unknown phenomena are investigated. First, it is demonstrated that in some conditions, the linear buckling mode shape may differ from the result of geometrically nonlinear analysis. Second, a mode jumping phenomenon is described as a transition from a secondary equilibrium path to an obscure one as a tertiary equilibrium path or a second bifurcation point. In this regard, some non-square plates with unsymmetric layer arrangements (in the presence of extension-bending coupling) are subjected to a uniaxial in-plane compression. By considering the geometrically linear and nonlinear problems, the bucking modes and post-buckling behaviors, e.g., the out-of-plane displacement of the plate versus the load, are obtained by ANSYS 2023 R1 software. Through a parametric analysis, the possibility of these phenomena is investigated in detail.