Junction Angle Research Articles

Experimental study of liquid–liquid dispersion patterns in T-inlet microchannels with different junction angles

Liquid-liquid two-phase flow in T-inlet microchannels with different junction angles (θ = 30°, 60°, 90°, 120° and 150°) was investigated experimentally. Four flow regimes of the dispersed phase were identified, i.e., parallel flow, jetting, dripping and squeezing, and the distribution of flow regimes for the dispersed phase corresponding to variations in the junction angle was plotted. The consequences of varying junction angle and flow conditions in the squeezing regime on the generated droplet size were analyzed. The results indicate that low capillary number and large flow rate ratio are conducive to the formation of large-size droplets. For constant flow conditions, junction angle θ = 90° is detrimental to the formation of squeezing microdroplets. The increase in microchannel junction angle causes the droplet size to decrease until θ > 90°, where the droplet size increases with the junction angle. On the basis of experimental results, the scaling law correlation equations containing the junction angle for predicting the droplet length and droplet volume are proposed, respectively. The predicted values match well with the experimental data. The results of this work contribute to the enhancement of the monodispersity of microdroplets and the precise control over a wide range of the generated droplet size by adjusting the junction angle.

The response mechanism of transversal mixing of dissolved oxygen to the evolution of secondary flow at the confluence

In the natural river network, the confluences play an important role as control nodes. It is of great scientific value to study the transport and mixing process of water quality at the confluence of the mainstream and tributaries to improve the health of the river environment. In this study, dissolved oxygen (DO, the essential survival conditions for aquatic organisms) was used as a water quality index, and a 3D transport model of DO considering atmospheric reoxygenation and biodegradation oxygen consumption was constructed. The hydrodynamic mechanism of DO transport, mixing and reoxygenation at confluence under different flow ratios, junction angles and water temperature conditions was studied. The results show that the secondary flow is the main driving force of the transversal mixing at confluence, and there is a high coupling relationship between the evolution of the secondary flow and the mixing process of water quality at confluence. With the increase of flow ratio and junction angle, the intensity of secondary flow at confluence shows an exponential increase, which in turn promotes the transversal mixing efficiency of DO at confluence. The water quality of the polluted confluence under different water temperature conditions showed a trend of gradual recovery, but the higher the water temperature, the weaker the recovery rate. This study can provide theoretical support to deal with the threat to aquatic organisms caused by pollution accumulation at confluence, and provide scientific basis for the improvement of the water environment and water ecology protection in the river confluence and downstream.

The TIGR triangle of the pineal region: a virtual reality anatomic study.

In this morphometric study, we describe the anatomy of the TIGR triangle, which is bordered by the tentorial surface of the cerebellum, the internal cerebral vein and vein of Galen complex, and the vein of Rosenthal. These structures define the window, or deep keyhole, to access the pineal region in non-midline supracerebellar infratentorial approaches. The posterior fossa anatomy of 16 patients was studied in virtual reality (VR), and the TIGR triangles were defined and measured with special attention on its angular orientation in the posterior fossa. The angular expanse of the posterior fossa was measured and recorded as the transverse-sigmoid junction (TSJ) angle. Because a perpendicular corridor through an anatomic aperture provides the best exposure, we studied the starting point along the TSJ angle that offers the best exposure of TIGR. In the 31 posterior fossa sides included in the study, the perpendicular trajectory through the TIGR triangle was on average 27.13° CI 95% (range: 5.97°-48.53°) from the midline. When comparing the SCIT variants, both the paramedian and lateral approaches provided near-perpendicular trajectory through the TIGR triangle in a majority of specimens. However, the modified paramedian approach, with starting point defined as TSJ angle/3, provided the most perpendicular path through the TIGR triangle. We studied the size, spatial orientation, and morphology of the TIGR triangle. Our data indicated that the best exposure of TIGR is through a modified paramedian SCIT approach, in which the starting point one third of the way from midline to the TSJ.

A numerical analysis of particle encapsulation in a flow-focusing droplet generation device

In this paper, the process of encapsulating solid particle(s) into liquid droplets in a high-throughput flow-focusing microchannel is investigated numerically. Open source software is used, which computes fluid flow in an Eulerian framework and particle dynamics with a Lagrangian approach. Previous studies have demonstrated that if no action is taken, particles suspended in a liquid passing through a flow-focusing microchannel will be encapsulated at random. This is perhaps unsurprising, but in one such study, less than 35% of droplets were found to contain exactly one particle. The two aims of this study are (i) to explore the flow patterns arising in a microfluidic channel and (ii) to elucidate the effect of salient governing parameters on encapsulation efficiency (i.e., the fraction of droplets encapsulating one particle) by focusing on ordering the particles before reaching the droplet generation section. Following validation against experimental reference data, the capillary number is varied across the three droplet generation regimes: squeezing, dripping, and jetting. We demonstrate that under certain conditions, an encapsulation frequency of 100% can be achieved with ordered particles, but in most cases, this is significantly lower. We examine the flow field to help understand how this non-uniform distribution of particles occurs. Notably, we find the dripping to be the best option for particle encapsulation and in this case extend the study to explore the effect of junction angle, finding that an angle of 60° is the most favorable. Improved understanding of the encapsulation process derived from this study can help to improve design of high-throughput droplet generation microfluidic systems.

Physics-based modelling of wind-driven junction fires

Numerical simulations of laboratory-scale junction fires were performed for a shrub fuel bed, using the fully-physical model FIRESTAR3D under various unidirectional wind conditions on different terrain slopes and junction angles. Simulations were carried out for a junction angle ranging from 15° to 90°, for a slope angle varying between 0 and 40°, and for low to intermediate driving wind speed, ranging from 0 to 4 m/s. Simulations show surge-and-stall-like behaviour of fire spread that is irregularly enhanced by the action of wind. Results of fire spread show that the effect of the junction angle on fire behaviour is non-linear, becoming stronger as the angle decreases. Both wind and slope effects are concealed by the junction effect for small angles, while wind has a significant impact at intermediate values of the junction angle. The driving heat transfer mode in junction fires varies based on the slope condition: on sloping terrain, convection is dominant for any wind speed, while on non-sloping terrain, radiation is the driving mode in no-wind condition but convection plays the greater role as the wind speed increases.

Investigation of rivers planform change in a semi-arid region of high vulnerability to climate change: A case study of Tigris River and its tributaries in Iraq

In this paper, the planform changes of rivers in a semi-arid region, which are particularly vulnerable to the impacts of climate change, were investigated. This research provides valuable insights into the adaptation and mitigation efforts necessary for effective climate change risk management in this area. A comprehensive analysis was carried out using satellite images and GIS to investigate the changes in the planform of the Mosul-Makhool reach of the Tigris River and its Lesser Zab and Greater Zab tributaries as a case study. To date, no studies have examined the impact of dam construction and climate change on the planform changes of these rivers. A survey was conducted to analyze the channel planform from 1979 to 2021. Various channel planform features were computed, including sinuosity index, braiding index, erosion and accretion, migration rate, confluence point, and junction angle. Results demonstrated that the Tigris River has low meandering features, the Lesser Zab has moderate meandering features, and the Greater Zab has the highest sinuosity index value of 1.95, which indicates very high meandering features. The change in the sinuosity index was fairly small. Generally, the rivers tended slightly towards deposition rather than erosion. The migration rate of the meandering rivers was high, with the highest value recorded in the Tigris River and Greater Zab. The average movement rate of the Greater Zab-Tigris River confluence was 31.81 m/year, and the Lesser Zab-Tigris River confluence moved 20.2 m/year. The study results demonstrate that climate change and dam construction significantly impact the rivers' planform in semi-arid regions. This investigation holds significant importance in evaluating morphodynamic changes in river systems worldwide with great detail and accuracy using satellite data.

Stiffness transitions in new walls post-cell division differ between Marchantia polymorpha gemmae and Arabidopsis thaliana leaves

Plant morphogenesis is governed by the mechanics of the cell wall-a stiff and thin polymeric box that encloses the cells. The cell wall is a highly dynamic composite material. New cell walls are added during cell division. As the cells continue to grow, the properties of cell walls are modulated to undergo significant changes in shape and size without breakage. Spatial and temporal variations in cell wall mechanical properties have been observed. However, how they relate to cell division remains an outstanding question. Here, we combine time-lapse imaging with local mechanical measurements via atomic force microscopy to systematically map the cell wall's age and growth, with their stiffness. We make use of two systems, Marchantia polymorpha gemmae, and Arabidopsis thaliana leaves. We first characterize the growth and cell division of M. polymorpha gemmae. We then demonstrate that cell division in M. polymorpha gemmae results in the generation of a temporary stiffer and slower-growing new wall. In contrast, this transient phenomenon is absent in A. thaliana leaves. We provide evidence that this different temporal behavior has a direct impact on the local cell geometry via changes in the junction angle. These results are expected to pave the way for developing more realistic plant morphogenetic models and to advance the study into the impact of cell division on tissue growth.

The mechanism of dissolved oxygen mixing and atmospheric reoxygenation at the confluence with different flow ratios and junction angles

As the control cell of river networks, the complex hydrodynamic conditions at river junctions pose significant challenges to pollution control and water ecology protection. The purpose of this study is to construct a 3D hydrodynamic model for dissolved oxygen (DO) transport at the confluence, studying its unsteady mechanism under different flow ratios and junction angles. The results of the study show that: i) The atmospheric reoxygenation distribution at the confluence exhibits a typical layered 3D feature, and the strong flow turbulence therein exerts a significant promoting effect on such reoxygenation. ii) The DO transport pattern at the confluence is characterized by the formation of an arc-shaped concentration distribution zone, followed by a contraction towards the opposite bank of the tributary and downstream transportation. A delay in DO concentration increase occurs within the separation area, while lateral oscillations are observed during downstream transport. iii) The flow ratio primarily governs the lateral migration extent of DO, while the junction angle serves as the main driver for downstream transport rate of DO. Increasing both flow ratio and junction angle can expedite mixing efficiency of DO at the confluence. The findings of this study can further enhance the hydrodynamic mechanism for water quality control at the confluent flume, and serve as a valuable reference for improving water environments and protecting water ecology in natural river confluence.

Metrics of Anterior Sclera in Normal Chinese Adults: Anterior Segment Imaging Using the Swept-Source Optical Coherence Tomography.

To measure the corneoscleral limbus and anterior sclera parameters of normal Chinese adults by swept-source optical coherence tomography (OCT). In this cross-sectional study, a total of 56 Chinese subjects with ametropia were evaluated in the Eye Hospital of Wenzhou Medical University from September 2020 to December 2020, including 26 (46.4%) men, with an average age of 24.7±1.8 years old. The OCT SS-1000 (CASIA, Tomey, Tokyo, Japan) was used to measure the sagittal height, corneoscleral junction (CSJ) angle, and scleral angle. The chord was across the corneal center and the line connecting the center of the cornea and the center of the chord was perpendicular to the chord. The mean sagittal height at chord lengths of 10.0, 12.3, and 15.0 mm were 1,756±72, 2,658±110, and 3,676±155 μm, respectively. The absolute values of the differences between horizontal and vertical meridians at three chord lengths were 54±40, 70±67, and 117±95 μm, respectively. One-way analysis of variance showed that the differences of CSJ angles at 12.3-mm chord and scleral angles at 15.0-mm chord in the four segments were statistically significant ( F values were 32.01 and 13.37, respectively, both P <0.001). The CSJ angles from low to high were 176.53±2.14° (nasal), 178.66±1.84° (inferior), 179.13±1.20° (temporal), and 179.31±1.68° (superior), and 87.5% of the nasal angles were less than 179°. The scleral angles from high to low were 38.35±2.47° (temporal), 38.26±3.37° (superior), 35.37±3.10° (nasal), and 35.30±4.71° (inferior). The morphology of corneoscleral limbus and anterior sclera is asymmetrical in normal Chinese adults. The nasal side of the corneoscleral limbus has the largest angle, and the superior and temporal sides of the scleral angle are larger.

Effect of geometry and hydraulic parameters on the bed morphology in a confluence using numerical approach

The confluence of rivers is an important phenomenon that is really vital for irrigation and water transmission networks. Investigation on bed morphology at the junction of two streams is of great importance. Flow complexity at confluences, as well as being at risks of rising water levels and flooding, interfering with the use of bridges, filling the inlets of the ponds and reducing the efficiency of water transport are resulted by this phenomenon. The purpose of this research is to investigate the effect of geometric and hydraulic parameters, such as junction angle, width ratio of two intersected canals, and Froude number on the bed morphology at intersection, using SSIIM2. Validation of the results of numerical model in terms of hydraulic and morphology parameters indicated good correlations coefficients of 0.9 and 0.68, respectively. In the next step, the effect of intersection angle (45, 60, 75, 90 and 105 degrees) on the scour depth was investigated. By decreasing the junction angle from 105° to 45°, the maximum scour depth reduced to about 96% and the scour hole dimensions were smaller and moved toward the confluence shore. Furthermore, the results showed that by increasing the width ratio from 0.5 to 1, and also, decreasing the Froude number ratio of tributary to main channel from 3 to 0.68, maximum scour depth decreased by 25% and 30%, respectively.

Droplet dynamics in asymmetric microfluidic junctions

Droplet-based microfluidics has received increasing interest over the last two decades, due to its extensive applications in drug delivery, cell encapsulation, protein crystallization, biochemical synthesis and high-throughput screening. As one of the key units in the microfluidic channels, asymmetric microfluidic junctions provide more opportunities to control and organize the droplets with different sizes, however, few studies have been reported to explore the effect of the junction angle on droplet behaviour in the asymmetric junctions. This work presents a numerical investigation of the droplet behaviour in asymmetric microfluidic junctions. The effect of the junction angle on the droplet breakup is explored in detail. Droplet breakup and non-breakup are found in asymmetric junctions. In the regime of the asymmetric breakup, the volume of the daughter droplet in the uphill branching channel is always larger than that in the downhill branching channel. Interestingly, in the regime of non-breakup, droplets are sorted into the uphill or downhill branching channels, suggesting that this asymmetric junction could be used for passive droplet sorting. The physical mechanisms behind droplet breakup and sorting are explored. Both the junction angle and the initial tip-to-tip length of the droplet play essential roles in the droplet behaviour in the asymmetric junctions. A phase diagram of the droplet behaviour is presented in this work. A scaling model is proposed to predict the transition between the breakup and non-breakup of the droplets in the asymmetric junctions.

The influence of soft contact lens material on the corneoscleral profile.

To objectively quantify changes in corneoscleral profile, as evaluated by the limbus position and corneoscleral junction (CSJ) angle, as a consequence of wearing different soft contact lens (CL) materials. Twenty-two healthy participants wore silicone hydrogel (SiHy, MyDay, CooperVision) and hydrogel (Hy, Biomedics 1 day extra, CooperVision) soft CLs for 8 h per lens in their left eye. In each session, corneoscleral topography was captured before and immediately after CL removal with an Eye Surface Profiler. Previously validated automatic and objective algorithms for limbal position and CSJ angle calculation were applied to 360 semi-meridians to investigate the effect of short-term CL wear on corneoscleral topography, globally and by sectors, depending on the soft CL material worn. Short-term soft CL wear significantly impacted limbal position (SiHy: 120 ± 97 μm, Hy: 128 ± 85 μm) and CSJ angle (SiHy: 0.57 ± 0.36°, Hy: 0.55 ± 0.40°); all p < 0.05. A statistically significant difference was found between the sectors with regard to limbus position and CSJ angle before CL wear that remained following lens wear (all pairwise comparisons, p < 0.001). Although individual differences were observed, there was no evidence that one material caused more substantial corneoscleral alterations. Corneoscleral profile parameters were altered significantly following 8 h of soft CL wear. The observed changes in limbus position and CSJ angle support the importance of participant-material biocompatibility.

Evaluation of Convective Heat Transfer and Natural Circulation in an Evacuated Tube Solar Collector

The evacuated tube solar collector ETC is studied intensively and extensively by experimental andtheoretical works, in order to investigate its performance and enhancement of heat transfer, for Baghdad climatefrom April 2011 till the end of March 2012. Experimental work is carried out on a well instrumented collectorconsists of 16 evacuated tubes of aspect ratio 38.6 and thermally insulated tank of volume 112L. The relationbetween convective heat transfer and natural circulation inside the tube is estimated, collector efficiency, effect oftube tilt angles, incidence angle modifier, The solar heating system is investigated under different loads pattern (i.eclosed and open flow) to evaluate the heat loss coefficient from tank and tubes, test the collector with variousaspect ratios (32.9 and 27.2). The enhancement in collector performance is studied by using two reflectors (FlatPlate and Curved Plate) and nanofluid (Water-AL2O3).Theoretical work is run by software (Fluent 6.3), to computethe velocity and temperature profiles within the tube, for different tube diameters, effect of tube junction angle andstagnant region in the bottom of the evacuated tube. The experimental results shows that the heat loss coefficientfor tube is W/m2.K and for tank is W/m2.K, the maximum collector temperature is 79°C in winter and99°C in summer, while that belong to nanofluid collector is 99°C in winter. The best tilted angle (optimum) ofevacuated tube is 41° annually. The collector efficiency increased when using nanofluid of (1, 0.6, 0.3)% volumefraction as(28.4, 6.8, 0.6)% respectively. The efficiency decreases as (33, 62)% when decreasing tube aspect ratiofrom 38.6% to 32.9% and 27.2% respectively. An increase of (16.9 and 7.08)% in collector efficiency is obtainedwhen using curved and flat plate reflectors respectively. From simulation the best junction angle of the tank is22.5°. The stagnant region is influenced with changing heat flux, tilted angle and aspect ratio.

Simulating the shrinkage-induced interfacial damage around Class I composite resin restorations with damage mechanics.

To investigate the shrinkage-induced damage at the composite-tooth interface by finite element analysis (FEA) using the cohesive zone model (CZM). Axisymmetric models of Class I restorations were created to illustrate the interfacial damage around composite resin restorations of different dimensions, with polymerization shrinkage modeled analogously to thermal shrinkage. The damage to the adhesive interface was determined using a CZM based on the fracture strength and fracture energy. To show the effects of damage, conventional models with perfectly bonded composite resin restorations were created as controls. The results indicated interfacial damage at the butt-joint cavosurface margin, dentinoenamel junction, and internal line angle. The percentage of damaged interfacial area was found to increase with decreasing diameter for restorations of the same height. For a given diameter, the damage was more severe for restorations of greater depth. The effects of the damage were further illustrated in the model with a restoration of 2-mm diameter and height. The interfacial damage occurred primarily at the internal line angle (83.3% of all the damaged interfacial area), leading to local stress relief (from 18.3MPa to 12.8MPa), but also higher stress at the damage fronts. Greater local shrinkage was found in composites adjacent to the damage. The damage mechanics-based CZM is an essential refinement of the FEA to predict interfacial damage and its implications. The extent of damage was found to be greater around restorations with smaller diameters and greater depths. The entire simulation is available via an open-source platform to facilitate further applications in adhesive dentistry.

Advantages of Posterior Indirect Decompression Surgery in Thoracolumbar Burst Fractures with Neurologic Symptoms

Objective: Approximately 90% of spinal fractures occur at the thoracolumbar (T-L) junction and may be accompanied by neurological symptoms, in which decompression and post-fixation are generally performed. However, decompression surgery can aggravate patients’ symptoms due to adverse incidents, such as developing postoperative hematomas or iatrogenic spinal cord injury. This study compared the surgical and radiographic outcomes of patients with T-L junction burst fractures and neurological deficits who underwent direct or indirect decompression.Methods: We retrospectively reviewed all patients who had undergone posterior surgical treatment for T-L junction burst fractures with neurologic deficits. Patients were classified according to the procedure: indirect decompression (group 1) or spinal decompression through laminectomy and facetectomy (group 2). Clinical results and radiologic findings were compared between the two groups for 2 years.Results: Among 57 patients who met the inclusion criteria, 29 were categorized into group 1, and 28 were categorized into group 2. Group 1 had a statistically significantly lower Oswestry Disability Index score than group 2 at the final follow-up visit (p=0.03). In group 1, both the T-L junction angle and wedge angle of the injured vertebrae improved significantly, both immediately after surgery (p=0.02 and p=0.01, respectively) and at the final follow-up visit (p=0.01 and p=0.01, respectively). In group 2, the difference between the pelvic incidence and lumbar lordosis was significantly greater than in group 1 at the final follow-up visit (p=0.02).Conclusion: This study confirmed that symptoms could be sufficiently improved with indirect decompression, which should be kept in mind for cases where it is difficult to perform direct decompression,

APC-driven actin nucleation powers collective cell dynamics in colorectal cancer cells

Cell remodeling relies on dynamic rearrangements of cell contacts powered by the actin cytoskeleton. The tumor suppressor adenomatous polyposis coli (APC) nucleate actin filaments (F-actin) and localizes at cell junctions. Whether APC-driven actin nucleation acts in cell junction remodeling remains unknown. By combining bioimaging and genetic tools with artificial intelligence algorithms applied to colorectal cancer cell, we found that the APC-dependent actin pool contributes to sustaining levels of F-actin, as well as E-cadherin and occludin protein levels at cell junctions. Moreover, this activity preserved cell junction length and angle, as well as vertex motion and integrity. Loss of this F-actin pool led to larger cells with slow and random cell movement within a sheet. Our findings suggest that APC-driven actin nucleation promotes cell junction integrity and dynamics to facilitate collective cell remodeling and motility. This offers a new perspective to explore the relevance of APC-driven cytoskeletal function in gut morphogenesis.

The quantitative response of pollutant spatial distribution and mixing dynamics to confluent conditions in an asymmetric open-channel confluence

River confluences are key nodes of pollutant transport in fluvial ecosystems and they are accompanied by complex hydrodynamic and mixing processes. The generalization and quantitative response of mixing to highly variable confluent conditions remain unclear. This studyinvestigates the spatial distribution and mixing process of pollutants through a series of meticulous experiments in an asymmetric open-channel confluence. Furthermore, we propose quantitative responses and characterization equations for the mixing rate and mixing metric for various confluent conditions, namely junction angle, momentum flux ratio, and width-depth ratio. The spatial distribution of pollutants have a strong three-dimensional structure, with a narrow-long pollution belt near the tributary and an almost vertical mixing interface adjacent to the downstream junction corner; this interface exhibits a logarithmic growth trend downstream and is affected by shear layer distortion. The standard deviation of the cross-sectional pollutant concentration at the confluence decreases gradually along with the downstream mixing of convergent flows, and the fitting curve slope increases as the junction angle, momentum ratio, and width-depth ratio increase. The mixing rate is promoted by the enhancements of helical motion, lateral advection, and turbulent diffusion caused by the strengthening of mutual deflection and lateral momentum flux under a large junction angle and momentum ratio, as well as the reductions of vertical velocity gradient and cross-sectional area under large width-depth ratio conditions. Sufficient and complete mixing occurs under a larger momentum ratio condition of >1 within a short distance of 4–5 widths of the main channel. In addition, the mixing metric shows a strong linear relationship with each of the three confluent conditions. In summary, the significant (p < 0.001) quantitative responses of the mixing rate and mixing metric can be characterized by a polynomial equation. These results have major implications for the systematic understanding of the three-dimensional distribution characteristics, mixing patterns, and mixing dynamics of pollutants at asymmetric confluences, as well as for the prediction or calculation of the downstream mixing metric.

Scheimpflug imaging for grading and measurement of corneo-scleral-profile in different quadrants.

The corneo-scleral-profile (CSP) describes the transition from cornea to sclera, while the corneo-scleral junction angle (CSJ), is the angle formed between the cornea and the sclera. The aims of this study were (i) to analyse the CSP and CSJ in different quadrants and (ii) to test correlation and repeatability of an established observational grading and measurement method, using Scheimpflug images. The nasal, temporal, superior and inferior CSP of 35 healthy eye participants (mean age 25.5 SD±3.1years; 20 female) was imaged using the corneo-scleral-profile module of the Pentacam (Oculus, Wetzlar, Germany). On the captured Scheimpflug images CSP was subjectively graded into five different corneo-scleral transitions, using the Meier grading scale (profile 1 fluid-convex; profile 2 fluid-tangential; profile 3 marked-convex; profile 4 marked-tangential; profile 5 concave). The CSJ was measured on the same images using ImageJ v1.8.0. Grading and measurement was repeated at a second session. Intra-observer reliability for the CSP-grading was analysed by Cohen's Kappa. Differences between repeated CSJ-measurements and different quadrants were analysed by paired-t-test and ANOVA. The eta-coefficient was used to determine the association between subjective CSP-grading and CSJ-measurement. Intra-observer reliability for the CSP grading system was poor (kappa=0.098) whereas repeated measurements of CSJ angle showed no statistically significant difference between sessions (0.04°; 95% CI - 0.21° to 0.29°; p=0.77). CSJ angles ranged from 172° to 180° with no statistically significant differences between nasal, temporal, superior and inferior (p=0.24). Eta-coefficient indicated a weak association between CSP-grading and CSJ-measurement (η=0.27; p=0.04). The subjective CSP-grading showed poorer repeatability than the objective CSJ-measurement, which did not detect any differences in angles between the meridians. The weak association between CSP-grading and CSJ-measurement is likely caused by the limited intra-observer reliability of the Meier grading scale. Furthermore, the CSP-grading scale seems to consider other aspects beside the CSJ angle, such as scleral radius.

Evaluation of maxillary palatal process pneumatization by cone-beam computed tomography

PurposeThe aim of this study is to investigate the pneumatization type of the palatal process (PTP) and angular and distance measurements of neighbouring structures on cone beam computed tomography (CBCT) images. Materials and Methods400 maxillary sinuses (MS) of 200 patients (96 female; 104 male; mean age: 43.2) were retrospectively evaluated. PTP was divided into three as types 1,2 and 3 and evaluated at distances 4, 8, 16, and 24 mm posterior to incisive foramen. The sinus and alveolar ridge height, palatonasal recess angle (PRA) and palatal junction angle (PJA) were also measured and recorded. ResultsPTP I (101, 25.3%) was the most frequent type, followed by PTP II (95, 23.8%), and the least was PTP III (4, 1%). In patients with PTP I, the alveolar ridge height in the 4 mm and 8 mm group was significantly higher than in the patients with PTP II and III (p<0.05). In patients with PTP I, PRA in the 4 mm and 16 mm groups was significantly higher than in patients with PTP II and III (p<0.05). Sinus and alveolar ridge height, PRA and PJA did not differ significantly between the right and left sides in the 4 mm, 8 mm, 16 mm, and 24 mm groups (p>0.05). ConclusionKnowing the anatomy of the MS is very important for a successful surgical procedure in this area. Anatomy and pathology of the MS can be understood more clearly in CBCT.

Physics-based modelling of junction fires: parametric study

Background Junction fires occur when two fire fronts merge. The rate of spread (ROS) and heat release rate (HRR) of the junction increase more quickly than that of each fire front, this effect exacerbated by slopes. Aims Numerical modelling of junction fires and an interpretation of their behaviour are given examining the key influencing factors. Methods Twenty physics-based simulations of laboratory-scale junction fires were performed for a shrub fuel bed using FIRESTAR3D, varying slope (0°–40°) and junction angles (15°–90°). Key results Accelerative and decelerative behaviours were observed for junction angles lower than 45°, but above this, deceleration was absent. The behaviour was firmly related to junction angle evolution, which controlled the flame and interactions between fire fronts. HRR followed similar trends; maximum HRR increased with increasing junction angle. Convection was the primary heat transfer mode in the initial propagation phase. In no-slope cases, radiation was the dominant method of heat transfer, but convection dominated fires on slopes. Conclusions The physics-based model provided great insight into junction fire behaviour. The junction angle was critical for determining ROS and fire behaviour. Implications The research helped to assess the effects of some topographical parameters in extreme fires. Situational awareness, operational predictions and firefighter safety will consequently improve.