Horizontal Cross-section Research Articles

Pressure swirl nozzles with different discharge orifice shapes injecting into transverse airflow

In this study, the influence of the discharge orifice shape of swirl liquid jets injected in transverse gas flow was investigated by high-speed photography and shadowgraphy techniques. Three shapes of discharge orifice, including circular, square, and elliptical were tested at different flow conditions. Due to the cross-sectional asymmetry in the ellipse, it is important to place it horizontally or vertically in airflow, and these two states are considered in this study. The main characteristics of liquid jets in transverse air, including trajectory, breakup point, jet width, breakup length, drop size distribution, and Sauter mean diameter, were obtained by image processing. Visualization of flow development revealed that the asymmetry of the swirl hollow cone in the transverse air causes an expanded new structure that cannot be seen in the circular cross section. This structure was called the conical bag and the inflated sheet in elliptical and square cross sections, respectively. The results indicate that the variations of momentum ratio are more effective in the path of non-circular swirl jets. The ellipse in the horizontal direction and square cross section have the breakup point's lowest transverse and longitudinal coordinates, respectively. Theoretical models for predicting swirl liquid jet trajectory and its breakup point were developed and presented. Gamma probability distribution function was fitted on the drop size according to the discrete distribution of the drop size. The results indicated that the distribution of elliptical shapes in the horizontal direction produces the smallest droplets among them while square cross section has a wider distribution.

A Comprehensive Review of Mixed Convective Heat Transfer in Tubes and Ducts: Effects of Prandtl Number, Geometry, and Orientation

This paper presents a comprehensive review of mixed convective heat transfer phenomena involving fluids with varying Prandtl numbers, specifically focusing on their behavior in different geometries and orientations. This study systematically explores heat transfer characteristics for fluids with low, medium, and high Prandtl numbers across a range of tube geometries, including circular, rectangular, triangular, and elliptical cross-sections, and examines their effects in both horizontal and vertical tube orientations. By consolidating existing research findings and analyzing various experimental and numerical studies, this review elucidates the complex interactions between fluid properties, tube geometry, and flow orientation that influence mixed convection heat transfer. Key insights are provided into the mechanisms driving heat transfer enhancements or degradations in different scenarios. In view of the findings from this paper, more than 84% of studies were conducted in a horizontal orientation and circular cross-section with a tendency to use medium-to-high Prandtl numbers as the working fluid for the past 10 years. This paper also identifies critical gaps in current knowledge and suggests future research directions to advance the understanding and application of mixed convective heat transfer in diverse engineering systems. Furthermore, apart from having different geometries applied in industrial applications, there is still room for improvement through the addition of passive methods to the heat transfer system, including helical coils, corrugations, swirl generators, and ribs. Overall, from the literature review, it is found that there are few relevant numerical simulations and experimental studies concentrating on middle Prandtl number fluids. Hence, it is recommended to perform more research on medium Prandtl number fluids that can be used as energy storage systems (ESS) in concentrating solar power plants, nuclear reactors, and geothermal systems.

(Invited) A New Perspective on Pore Growth in Anodic Alumina Films

Pores in the porous-type anodic oxide film of aluminum have conventionally been thought to grow vertically in a straight tube-like manner. However, branching and nano-branching pores (referred to as feather-like) typically observed in films generated in chromic acid solutions are considered non-steady-state morphologies. However, are these formed only under specific conditions? These have also been observed in neutral borate electrolytes, highlighting the need to clarify the dominant factors governing pore morphology. In this study, we report the results of observations and discussions on the fine structure of pore morphology, including typical films grown in oxalic acid or sulfuric acid, using state-of-the-art analytical techniques to elucidate the dominant factors influencing pore formation [1].Observation of the initial pore formation in the three types of electrolytes, sulfuric acid, oxalic acid, and phosphoric acid, reveals that the initial pores are considerably smaller in diameter and more numerous than the main pores. This is presumed to be due to pore formation through dissolution under low electric field strength caused by the presence of a thick barrier layer. Observation of the growth process of pores generated in sulfuric acid and oxalic acid electrolytes using high-resolution TEM revealed that neither film grows in a tubular manner but rather undergoes repeated branching at a fine scale. The cause of nano-branching in the main pores is similarly attributed to thickening of the barrier layer for some reason in the electrolyte, resulting in a decrease in the electric field. Thus, it is considered that pores do not grow in a straight tube-like manner but rather universally involve branching, and the grown pores are subsequently smoothed out by chemical dissolution.These results thus indicate that the formation of radial nano-branched pores is not unique to chromic acid films. Instead, this is a universal phenomenon of anodic films that frequently occurs when the electric field strength decreases during anodizing for the same reason. When Thompson et al. first reported horizontal cross-section observations of various porous anodic films in 1978, they stated that “steady-state anodizing is not as regular as previously assumed”. This remains true, and elucidation of the actual structure of the porous film is important for more effective application of the film.[1] S. Ono, H. Asoh, Electrochem. Comm. (2021). Figure 1

Material Flow and Microstructural Evolution in Friction Stir Welding of LAZ931 Duplex Mg-Li Alloys

The material flow behavior during friction stir welding (FSW) plays a critical role in the quality of final joints. In this study, the FSW of LAZ931 duplex Mg alloy was carried out at a rotation speed of 800 rpm and welding speeds of 50, 100, and 200 mm/min, respectively. A thin pure Mg strip inserted at the interface between the two Mg-Li alloy plates was used as a marker to study the flow behavior of the materials in the FSW process. Sound welds with no defects were obtained for all three welding speeds. The microstructural evaluations along the marker on the horizontal cross-section around the keyhole of the welds were characterized. As the welding speed increased, the marker came closer to the keyhole, indicating the decreased extent of the plastic deformation of the material. In the shoulder-affected zone (SAZ), the thickness of the marker reduced gradually in the accelerating stage and finally accumulated together in the decelerating stage. However, in the pin-affected zone (PAZ), the thickness of the marker reduced sharply in the accelerating stage and then became dispersed in the decelerating stage, and the degree of dispersion decreased as the weld speed increased. As a result, an elongated grain structure was formed in the SAZ, while two equiaxial grain structures were formed in the PAZ. The material on the advancing side was refined by the pin and deposited in the weld to form a fine equiaxial grain structure due to the high strain rate. In contrast, the material on the retreating side was pushed by the pin and thus directly deposited in the weld to form a coarse equiaxial grain structure. In addition, the area of the fine equiaxial grain structure was reduced obviously with the increase in welding speed.

Development of criteria for assessment of gas channelling phenomenon inside the blast furnace

Gas channelling is an uneven distribution of ascending gas through the burden layers in the blast furnace. This occurs due to the difference in permeability across the horizontal cross-section, which reduces the operational efficiency. When unattended, channelling can aggravate hanging and may further lead to burden slippage and chilling of the hearth, which is a nightmare for the blast furnace operator. The objective of this work is to develop a gas channelling assessment system based on statistical modelling by analysing the real-time data for parameters like stave temperature, pressure, gas utilisation ratio and uptake temperature. The criteria, which are indicative of the fluctuations in physical and chemical process parameters during gas channelling, are developed from process knowledge and theoretical understanding of the channelling with historical data of one of the blast furnaces of Tata Steel Jamshedpur, India. Optimum combinations of the criteria are found through fine-tuning of the statistical parameters and cross-validation with the preexisting events of gas channelling. The model is run on the test dataset, and the accuracy of the model is presented.

Imaging Metabolic Flow of Water in Plants with Isotope-Traced Stimulated Raman Scattering Microscopy.

Water plays a vital role in the life cycle of plants, participating in various critical biochemical reactions during both non-photosynthetic and photosynthetic processes. Direct visualization of the metabolic activities of water in plants with high spatiotemporal resolution is essential to reveal the functional utilization of water. Here, stimulated Raman scattering (SRS) microscopy is applied to monitor the metabolic processes of deuterated water (D2O) in model plant Arabidopsis thaliana (A. thaliana). The work shows that in plants uptaking D2O/water solution, proton-transfer from water to organic metabolites results in the formation of C-D bonds in newly synthesized biomolecules (lipid, protein, and polysaccharides, etc.) that allow high-resolution detection with SRS. Reversible metabolic pathways of oil-starch conversion between seed germination and seed development processes are verified. Spatial heterogeneity of metabolic activities along the vertical axis of plants (root, stem, and tip meristem), as well as the radial distributions of secondary growth on the horizontal cross-sections are quantified. Furthermore, metabolic flow of protons from plants to animals is visualized in aphids feeding on A. thaliana. Collectively, SRS microscopy has potential to trace a broad range of matter flows in plants, such as carbon storage and nutrition metabolism.

Laser Scanner-Based Hyperboloid Cooling Tower Geometry Inspection: Thickness and Deformation Mapping.

Hyperboloid cooling towers are counted among the largest cast-in-place industrial structures. They are an essential element of cooling systems used in many power plants in service today. Their main structural component, a reinforced-concrete shell in the form of a one-sheet hyperboloid with bidirectional curvature continuity, makes them stand out against other towers and poses very high construction and service requirements. The safe service and adequate durability of the hyperboloid structure are guaranteed by the proper geometric parameters of the reinforced-concrete shell and monitoring of their condition over time. This article presents an original concept for employing terrestrial laser scanning to conduct an end-to-end assessment of the geometric condition of a hyperboloid cooling tower as required by industry standards. The novelty of the proposed solution lies in the use of measurements of the interior of the structure to determine the actual thickness of the hyperboloid shell, which is generally disregarded in geometric measurements of such objects. The proposal involves several strategies and procedures for a reliable verification of the structure's verticality, the detection of signs of ovalisation of the shell, the estimation of the parameters of the structure's theoretical model, and the analysis of the distribution of the thickness and geometric imperfections of the reinforced-concrete shell. The idea behind the method for determining the actual thickness of the shell (including its variation due to repairs and reinforcement operations), which is generally disregarded when measuring the geometry of such structures, is to estimate the distance between point clouds of the internal and external surfaces of the structure using the M3C2 algorithm principle. As a particularly dangerous geometric anomaly of hyperboloid cooling towers, shell ovalisation is detected with an innovative analysis of the bimodality of the frequency distribution of radial deviations in horizontal cross-sections. The concept of a complete assessment of the geometry of a hyperboloid cooling tower was devised and validated using three measurement series of a structure that has been continuously in service for fifty years. The results are consistent with data found in design and service documents. We identified a permanent tilt of the structure's axis to the northeast and geometric imperfections of the hyperboloid shell from -0.125 m to +0.136 m. The results also demonstrated no advancing deformation of the hyperboloid shell over a two-year research period, which is vital for its further use.

Influence of a Background Shear Flow on Cyclone–Anticyclone Asymmetry in Ageostrophic Balanced Flows

In this paper, we study how cyclonic and anticyclonic vortices adapt their shape and orientation to a background shear flow in an effort to understand geophysical vortices. Here we use a balanced model that incorporates the effects of rotation and density stratification to model the case of an isolated vortex of uniform potential vorticity subjected to a background shear flow that mimics the effect of surrounding vortices. We find equilibrium states and analyze their linear stability to determine the vortex characteristics at the margin of stability. Differences are found between the cyclonic and anticyclonic equilibria depending on the background flow parameters. When there is only horizontal strain, the vertical aspect ratio of the vortex does not change, whereas increasing the imposed background strain rate causes a change in the horizontal cross section, with cyclones being more deformed than anticyclones for a given value of strain. Vertical shear not only causes changes in the vertical axis but also causes the vortex to tilt away from it upright position. Overall, anticyclonic equilibria tend to have a more circular horizontal cross section, a longer vertical axis, and a larger tilt angle with respect to cyclonic equilibria. The strongest asymmetry between the horizontal cross section of cyclonic and anticyclonic vortices occurs for low values of vertical shear, while the strongest asymmetry in the vertical axes and tilt angle occurs for large vertical shear. Finally, by expanding the vortex shape and orientation in terms of the strain rate, we derive simple formulas that provide insights into how the vortex equilibria depend on the background flow.

Modified technique for sutured scleral fixated intraocular lens in a patient with post-traumatic aniridia and aphakia: a case report

BackgroundA modified surgical technique of sutured scleral fixated intraocular lens (SSF-IOL) was applied in a patient with post-traumatic aniridia and aphakia.Case presentationA 51-year-old man was referred to our clinic with decreased vision (finger count) in his right eye. This patient had previously undergone primary repair of the ruptured globe and pars plana vitrectomy to manage ocular trauma in the same eye. On presentation, the best corrected visual acuity in his right eye was 20/40. The slit lamp examination of his right eye revealed loss of total iris and lens. Corneal endothelial cell density was 1462 cells/mm2. Fundoscopic examination of the right eye revealed a retinal attachment. For IOL implantation, a rigid poly methyl methacrylate IOL was used with a 2-point scleral fixation performed using a polypropylene suture. One year postoperatively, the uncorrected distance visual acuity was 20/32, and the manifest refraction was − 0.5/–1.5 × 130 (20/20). Pentacam revealed that the astigmatism of the anterior corneal surface and the total cornea was 1.1 D (axis: 59.8°) and 1.0 D (axis: 35.6°), respectively. The horizontal (3°–183°) cross-section image displayed an IOL with a 1° tilt and 0.425 mm decentration. The patient reported no dysphotopsia or photophobia and was satisfied with the visual results. OPD-scan III revealed that higher-order aberrations in the right eye were slightly higher than those in the left eye. No suture-related or other serious complications were observed.ConclusionThe modified SSF-IOL technique can offer improved visual quality for patients with aniridia and aphakia by ensuring proper IOL positioning and reducing astigmatism.

Anatomical evaluations of the adipose tissue surrounding the flexor hallucis longus tendon

This study aimed to evaluate the presence of adipose tissue surrounding the flexor hallucis longus (FHL) tendon through gross dissection and magnetic resonance imaging (MRI). Grossly, we observed the FHL tendon and surrounding tissues in nine cadavers. Using MRI, we quantitatively evaluated each tissue from the horizontal plane in 40 healthy ankles. Macroscopic autopsy revealed the presence of adipose tissue behind the ankle joint between the FHL and fibula, and horizontal cross-sections showed an oval-shaped adipose tissue surrounding the tendon. The cross-sectional area on MRI was 14.4 mm2 (11.7–16.7) for the FHL tendon and 120.5 mm2 (100.3–149.4) for the adipose tissue. Additionally, the volume of the adipose tissue was 963.3 mm3 (896.2–1115.6). There is an adipose tissue around FHL tendon and maybe this close anatomical relationship might influence the function of the tendon and be involved in its pathologies.

Imaging-Based Detection of Anterior Chamber Inflammation: A Comparative Diagnostic Accuracy Study

PurposeWe investigated the impact of operator parameters on the diagnostic performance of danterior segment optical coherence tomography (AS-OCT) in anterior uveitis. DesignProspective comparative diagnostic analysis. MethodsSetting: Single site.Study Population: Children aged under 18 years with anterior uveitis, recruited consecutively.Observation Procedures: Index testing: Optovue RTVue80 AS-OCT using ‘low-volume’ (LV, horizontal and vertical cross-sections) and ‘high-volume’ (HV, 68 horizontal cross-sections) protocols. Reference testing: slit lamp examination with anterior chamber inflammation graded using standardisation of uveitis nomenclature (SUN).Main Outcome Measure: Index test performance metrics (sensitivity, specificity, likelihood ratios), utility for ‘ruling-in’ and ‘ruling-out’ disease (positive / negative predictive values, PPV/NPV), receiver operating characteristic (ROC) curves to explore the impact of different imaging derived metrics, multivariable multilevel regression analyses to quantify correlation of index to reference testing, and repeatability indices across protocols. Results40 children (77 eyes: 51 eyes at SUN grade 0, 10 at SUN0.5+, 8 at SUN1+, 8 SUN≥2+ or higher) were included. There was high repeatability across protocols (0.98, p<0.001, 95% CI 0.75-1.0). OCT resulted in strong predictive values for ‘ruling-out’ (LV-scan NPV 82.9%, 95% CI 71.5 - 90.4%; HV-scan NPV 100%, 95% CI 3% to 100%), and but less predictive value for ‘ruling-in’ SUN≥0.5+ (LV-scan PPV 52.8% 95% CI 41.5 - 63.7%; HV-scan PPV 34.2%, 95% CI 33.3 to 35.1%). Detection of more than 1 cell within a cross sectional scan was strongly suggestive of clinical activity, with area under the curve of 0.76 (95% CI 0.62 - 0.89) for SUN≥0.5+, and 0.85 (95% CI 0.73- 0.98), for the detection of SUN≥1+. Cell count correlated with SUN grades at higher levels of inflammation (SUN≥2+ both protocols, SUN≥1+ HV-scans). There was an independent positive association between age and AS-OCT cell (adjusted correlation coefficient 0.2 cells for each additional year of age). ConclusionsOperator dependent factors impact the diagnostic and quantification performance of AS-OCT for anterior chamber inflammation. However, the strong, ‘dose-respondent’ correlation of low-volume protocols with SUN grading promises clinical utility without the storage and analysis burden of high-volume approaches. Further work will involve exploration of the need for age-specific image metric interpretation.

Učinak veličine stupa i kuta nagiba pukotina na stabilnost podzemnih prostorija u poroznim vapnencima

Pillars play an essential role in the stability of an underground cavity. Their most important parameters are the dimensions, material parameters, condition, and joint geometry. This research investigates the impact of geometrical horizontal cross section and joint’s dip angle on the stability of the pillar, which affects the stability of cavities. The chosen study site is in a cellar system in Budapest, Hungary. According to the laboratory and on-site investigations, the cellar’s host rock is porous limestone with a low strength but a massive rock mass with few discontinuities. In some of the previously investigated cellar systems the edge of the pillars was cut because of space requirements. Therefore, this study aims to determine the effect of such geometrical changes on the stability of the cellar. A 25 m2 room with a single square-based pillar was used to model the stability. Material parameters were determined through various laboratory tests such as UCS, triaxial, and discontinuity shear strength tests, as well as rock mass classification. Three-dimensional finite element software (RS3) was used to evaluate the stability of the studied pillar. Overall, this study provides valuable insights into the factors that influence stability of pillars in underground cavities and highlights the importance of carefully considering these factors when designing, verifying, and constructing support systems for underground structures.

A case study on early-age cracking of high-strength concrete construction by coupled thermal-mechanical analysis and field monitoring

The use of high-strength concrete (HSC) in constructing high-rise reinforced concrete buildings and their deep foundations is becoming more popular because of the significant reduction in member size and, thus, self-weight in structural members. However, the higher cement content in HSC may result in increased heat of hydration and autogenous shrinkage, growing concerns about forming early-age cracks in HSC structural members. This case study assessed the early-age cracking of HSC in bored pile construction of high-rise buildings. A nonlinear transient coupled thermal-mechanical response analysis was performed to evaluate the potential of early-age cracking caused by the heat of hydration generated in the HSC using ABAQUS and two subprograms, USDFLD and UEXPAN. A 3-D finite element model was developed considering thermal effects, time-dependent evolution of early-age strength and stiffness of HSC, crack strain development, autogenous shrinkage, and stress-relaxation in the analysis. Field measurements were carried out on a 3-m diameter bored pile constructed using Grade C50/60 HSC (fck,cube = 60 MPa) for a high-rise building project in Hong Kong to evaluate the validity of the numerical model. Optical fiber sensors were used to monitor the temperature changes of the pile for approximately 380 hours after casting. The temporal and spatial temperature distributions measured in the field measurements agree well with the simulations. Large thermal gradients and high tensile stress zones were observed across the horizontal cross-sections of the pile, resulting in the formation of vertical annular cracks. Based on the results of the analysis, the maximum crack widths were predicted and compared with the durability crack width limits.

The Planar Mixing Layer Flame (PMLF): a canonical configuration for studying non-premixed combustion chemistry and soot inception

The study of fuel chemistry and soot inception in non-premixed combustion can be advanced by characterizing flame configurations in which the advection and diffusion transport can be finely controlled, with the ability to decouple pyrolysis from oxidation. Also, the ideal flames to be investigated should be perturbed minimally by probes and thick enough for sampling techniques to yield spatially resolved measurements of their structure. The Planar Mixing Layer Flame (PMLF) configuration introduced herein is established between a fuel and an oxidizer slot jet adjacent to each other and shielded from the ambient air by annularly co-flowing inert nitrogen. The PMLF flow is kept laminar and steady by an impinging flat plate equipped with a rectangular exhaust slit opening which anchors the position of the hot combustion products via buoyancy. The PMLF is accessible to sampling and its flow stability is preserved when using any tested probe. The experiments are complemented with 2D- Computational Fluid Dynamics (CFD) modeling with detailed chemical kinetics. The results demonstrate that the PMLF has a self-similar boundary layer structure whose horizontal cross-sections are equivalent to properly selected and equally thick 1D- Counterflow Flames (CFs). The equivalence allows for excellent predictions of the PMLF thermochemical structure characterized experimentally but at a small fraction of the 2D-CFD computational cost. The 1D-CF equivalence affects even aromatics less than twofold despite their kinetics being known to be very sensitive to the temperature field. Importantly, the PMLF thickness is several millimeters and grows at increasing HABs so that the equivalent 1D-CFs have strain rates as small as 7.0 /s which cannot be studied in CF experiments. As a result, the PMLF emerges as a promising canonical non-premixed flame configuration for studying flame chemistry and soot inception on time scales of tens of milliseconds typical of many combustion applications.

Effects of different irrigation activation methods on root canal treatment of primary teeth.

There is currently a lack of research on the application of newly developed irrigation techniques in root canal treatment of primary teeth. This study aimed to evaluate the effects of various irrigation activation techniques on two key parameters: apical debris extrusion (ADE) and dentinal tubule penetration depth (DTPD) of the root canal filling material. A total of 96 primary mandibular second molars were randomly divided into 4 groups: Group 1-Conventional Needle Irrigation (CNI), Group 2-XP-Endo Finisher (XPF), Group 3-EndoActivator (EA), and Group 4-Passive Ultrasonic Irrigation (PUI). In all groups, the One Reci single-file system was used for root canal preparation. For ADE measurement, each group was rinsed with distilled water. For DTPD assessment, sodium hypochlorite (NaOCl) was applied. ADE quantification was performed by collecting debris in pre-weighed Eppendorf tubes. A combination of fluorescent dye and root canal filling material (DiaPex Plus) was used for root canal filling. In order to examine DTPD, horizontal cross-sections of the coronal and apical regions of the teeth were taken with a thickness of 1 mm. The maximum and mean DTPD was examined by confocal laser scanning microscopy. Data were analyzed using the Kruskal-Wallis, One-way ANOVA, and Mann-Whitney U tests (p = 0.05). As a result, PUI had the highest mean ADE and CNI had the lowest mean ADE, while CNI had the highest mean DTPD in both the coronal and apical regions, whereas PUI had the lowest mean DTPD in the coronal region, and EA had the lowest mean DTPD in the apical region. There were no statistically significant differences in DTPD and ADE among the four groups. Comparing intragroup maximum DTPD across all groups, it was significantly higher in the coronal region than in the apical region (p < 0.05). ADE and DTPD of root canal filling materials in primary teeth did not differ significantly among CNI, XPF, EA and PUI irrigation activation techniques.

Diagnosis of Forme Fruste Keratoconus Using Corvis ST Sequences with Digital Image Correlation and Machine Learning.

This study aimed to employ the incremental digital image correlation (DIC) method to obtain displacement and strain field data of the cornea from Corvis ST (CVS) sequences and access the performance of embedding these biomechanical data with machine learning models to distinguish forme fruste keratoconus (FFKC) from normal corneas. 100 subjects were categorized into normal (N = 50) and FFKC (N = 50) groups. Image sequences depicting the horizontal cross-section of the human cornea under air puff were captured using the Corvis ST tonometer. The high-speed evolution of full-field corneal displacement, strain, velocity, and strain rate was reconstructed utilizing the incremental DIC approach. Maximum (max-) and average (ave-) values of full-field displacement V, shear strain γxy, velocity VR, and shear strain rate γxyR were determined over time, generating eight evolution curves denoting max-V, max-γxy, max-VR, max-γxyR, ave-V, ave-γxy, ave-VR, and ave-γxyR, respectively. These evolution data were inputted into two machine learning (ML) models, specifically Naïve Bayes (NB) and Random Forest (RF) models, which were subsequently employed to construct a voting classifier. The performance of the models in diagnosing FFKC from normal corneas was compared to existing CVS parameters. The Normal group and the FFKC group each included 50 eyes. The FFKC group did not differ from healthy controls for age (p = 0.26) and gender (p = 0.36) at baseline, but they had significantly lower bIOP (p < 0.001) and thinner central cornea thickness (CCT) (p < 0.001). The results demonstrated that the proposed voting ensemble model yielded the highest performance with an AUC of 1.00, followed by the RF model with an AUC of 0.99. Radius and A2 Time emerged as the best-performing CVS parameters with AUC values of 0.948 and 0.938, respectively. Nonetheless, no existing Corvis ST parameters outperformed the ML models. A progressive enhancement in performance of the ML models was observed with incremental time points during the corneal deformation. This study represents the first instance where displacement and strain data following incremental DIC analysis of Corvis ST images were integrated with machine learning models to effectively differentiate FFKC corneas from normal ones, achieving superior accuracy compared to existing CVS parameters. Considering biomechanical responses of the inner cornea and their temporal pattern changes may significantly improve the early detection of keratoconus.

Numerical study of raceway behaviours of a slow-moving packed bed solid fuel gasifier

The moving-bed gasifier of solid fuels (e.g., coal or biomass) is a key chemical reactor to convert coal or biomass to clean fuel, where the profile of the raceway cavity and its flow-thermal-chemical behaviours can affect the performance of the gasifier, however, they are not well understood because of the process complexity and modelling challenge. In this study, an advanced 3D multi-fluid model, based on the Eulerian-Eulerian method, coupled with heat transfer and heterogenous reactions, is developed to describe the reacting flow behaviours inside and around the raceways. It is found that raceways inside the slow-moving packed bed gasifier are of balloon-like shapes; they are built in just a few seconds after issuing the jet from gas entry, and then both the average velocity for gas and particle are relatively stable. The gauge pressure conditions are not isobaric, and high temperatures, small gas densities and high reaction rates are observed near the raceway “shell”. Besides, it is found the raceway behaviours on horizontal cross-section feature more symmetry compared to those on other directions. In addition, probability theory and statistics are used to analyse the quantitative raceway results, and possibilities related to the distributions of gas properties, momentum and species are discussed. This model provides an effective tool to systematically study and optimise raceway behaviours inside a slow-moving packed bed solid fuel gasifier.

Buoyancy influences on local heat transfer characteristic of supercritical LNG across the pseudo-phase transition in variable cross-section horizontal channels

The regasification process within the printed circuit heat exchanger (PCHE) channel for supercritical liquefied natural gas (S-LNG) will produce a large temperature difference. This process is considered a pseudo-phase transition process, and the resulting density difference driving buoyancy has a crucial action in influencing the heat transfer and flow of S-LNG. Three horizontal variable cross-section channels are established to examine the buoyancy impact on the local heat transfer and flow of S-LNG within the pseudo-phase transition process in the PCHE channel. It comprehensively analyzes the buoyancy impact on local heat transfer and flow under different channel shapes and mass flow rates. The findings demonstrated that the eddy blockage caused by buoyancy mainly acts on the top of the channel and mainly occurs in the liquid-like and pseudo-critical regions, resulting in the deterioration of local heat transfer on the upper and lower walls of the channel. The hybrid channel achieves the intended design goal, and the diverging channel is almost unaffected by buoyancy. The overall performance evaluation criterion (PEC) is used to evaluate the thermal and hydraulic performance of each channel under different mass flow rates. The data show that the diverging channel has the best thermal and hydraulic performance, and its PEC can reach 1.28. The hybrid channel also achieves the expected effect, and its PEC can reach 1.09.

Selection of areas prospective for the search of primary hydrogen in the territory of Ukraine (based on the data of the 3D P-velocity model of the mantle)

The work aimed to identify promising areas for the search for primary hydrogen in Ukraine using a 3D P-velocity model of the mantle under Ukraine and its surroundings. The work uses a 3D P-velocity model of the mantle under the territory of Ukraine and its surroundings from a depth of 50 to 1700 km north of 50° NL and up to 2500 km to the south. The model is derived using ISC bulletin data from 1964 and is presented as horizontal and vertical cross-sections.&#x0D; Since the manifestation of hydrogen is primarily associated with the release of ultra-deep fluid tracks in the mantle, a brief analysis of them was presented. A detailed analysis of all nine superdeep mantle fluids isolated on the territory of Ukraine and their velocity characteristics was carried out. A comparison of the location of the routes of passage of superdeep fluids and the velocity structure of the mantle of the considered territory showed that they are confined to tectonically activated areas. In order to confirm the possible pre­sence of primary hydrogen in selected tracks of superdeep mantle fluids, heat flow density maps, a temperature map at a depth of 50 km, a map of the depth of the Moho boundary, a conductivity density map, and a fault map of the Ukrainian Shield were considered.&#x0D; A comparative analysis of maps of the location of superdeep mantle fluids and regions on the territory of Ukraine with increased heat flow, increased depth of the Moho boun­dary, and the presence of mantle conductors and faults was carried out. Summarizing the results of the comparative analysis, the most promising areas for the search for primary hydrogen were selected, corresponding to the following routes of superdeep fluids: f12, the northeastern part of f3, the southern part of f4 (the area of the Dnipro-Donetsk basin), the southwestern part of f1 (the area of the Western Ukrainian oil and gas-bearing region) and f9 and f10 (region of the South Crimean oil and gas-bearing province).

Analysis of food inflation convergence in NUTSII regions of Türkiye

In this research, it is examined whether the increase in food inflation observed in Turkey in recent years due to global factors as well as the slowdown in food inflation convergence among regions. In this context, the research aims to analyze the food inflation convergence among NUTS II regions. Since it takes into account the effect of global shocks, tests that take structural break into account are used. In addition, first and second generation tests that do not take into account the structural break are also used and the all test findings are compared. The findings differ according to the consideration of horizontal cross-section dependence and structural break. In addition, the findings also vary according to the a priori determination of the structural break. According to the findings of the test taking into account the soft break, the existence of food inflation convergence among regions except TR83 region is found. The second generation test findings also support this result. In line with the findings, it is concluded that the increase in food inflation observed in Turkey in recent years is not due to the slowdown in food inflation convergence across regions.