Delta Shape Research Articles

New anti-mesenteric delta-shaped stapled anastomosis: Technical report with short-term postoperative outcomes in patients with Crohn's disease.

Medical treatment for Crohn's disease (CD) has continuously improved, which has led to a decrease in surgical recurrence rates. Despite these advancements, 25% of patients will undergo repeat intestinal surgery. Recurrence of CD commonly occurs on the mesentery side of the anastomosis site. To compare the new anti-mesenteric side-to-side delta-shaped stapled anastomosis (DSA) with the conventional stapled functional end-to-end anastomosis (CSA). This retrospective study included CD patients who underwent ileo-ileal or ileo-colic anastomosis between January 2020 and December 2023. The DSA technique employed a stapler to maintain the concept of anti-mesentery side-to-side anastomosis by performing a 90° vertical closure of the open window compared with the CSA technique. At the corner where the open window is closed, the DSA avoids forming a pouch and creates an anastomosis resembling a delta shape within the intestinal lumen. We compared demographics, preoperative condition, operative findings, and operative outcomes for the two techniques. The study included 175 patients, including 92 in the DSA group and 83 in the CSA group. The two groups were similar in baseline characteristics, preoperative medical treatment, and operative findings except for the Montreal classification location. The 30-days postoperative complication rate was significantly lower in the DSA group compared with the CSA group (16.3% vs 32.5%, P = 0.009). Ileus incidence was significantly lower in the DSA group than in the CSA group (4.3% vs 14.5%, P = 0.033), and the hospital stay was shorter in the DSA group than in the CSA group (5.67 ± 1.53 days vs 7.39 ± 3.68 days, P = 0.001). The DSA technique was feasible and showed comparable postoperative outcomes with lower short-term complications compared with the CSA technique. Further studies on CD recurrence and long-term complications are warranted.

Effects of upstream and downstream boundary conditions on lacustrine shallow-water delta morphologies: A numerical modeling approach

Lacustrine shallow-water deltas exhibit highly variable morphologies, owing to their high sensitivity to changes in the upstream and downstream boundary conditions, where a small change significantly alters their morphology. In this study, we present the results from a numerical model (DELFT3D) used to explore the mechanism of distributary network amalgamation and delta evolution under various boundary conditions. We established a reference case to model the delta building-out process considering the basin water depth difference (shallow and deep). Geological and hydrodynamic models were established by varying the water level under a steady river discharge and sediment supply. Despite similar initial conditions, each modeled delta exhibits a unique morphological evolution, progressing through distinct stages: (i) formation of unstable, narrow channels with quasi-radial shapes; (ii) channel development, shaping the delta based on controlling factors; (iii) reduction of deltaic activity and increased channel avulsion due to delta submergence, and; (iv) new channels emerging, paving the way for reshaping and migration towards new paths, resulting in fewer bifurcations and straighter channels. Quantitative relationships characterizing delta morphology and distributary channels were established, and the following results were noted: (i) a positive correlation between active and abandoned channels, distributary channel network opening angle, and delta area with discharge and sediment grain size, and negative correlation with basin depth and falling water level; (ii) a positive correlation of lobe elongation with basin depth and discharge, and a negative correlation with sediment grain size; and (iii) roughness and length-to-width ratio emerging as key predictors of delta shape. By applying the model predictions to real-world scenarios, including modern deltas (Sile and Chiemsee) and ancient systems (Bohai Bay Basin), this study can provide valuable insights into the dynamics of lacustrine deltaic systems and their responses to changing boundary conditions. This highlights the importance of understanding deltaic systems for both theoretical research and practical applications.

Effect of Roll Angle Configurations of a Reverse Delta Type Add-on Device on Wing Tip Vortex Alleviation

An add-on device in the shape of a reverse delta has shown the ability to alleviate wake vortices. The present work studies the interaction of the wing tip vortex and the reverse delta type add-on device vortices. This paper looks at the vortex interactions generated downstream of the wing tip in planes perpendicular to the free stream direction and their dependence on roll angles φ at a mean chord-based Reynolds number of Rec=2.75×105. The study reveals that the add-on device causes a reduction in the tangential velocity V and vorticity of the resultant vortex by up to 44.1% and 59.4%, respectively. Also, it is found that the resultant vortex core radius increased by 305%. The results indicate that the reverse delta type add-on device implants countersign vorticity into the wing tip vortex and modifies its roll-up process.

Leaf litter decomposition and detrital communities following the removal of two large dams on the Elwha River (Washington, USA)

Large-scale dam removals provide opportunities to restore river function in the long-term and are massive disturbances to riverine ecosystems in the short-term. The removal of two dams on the Elwha River (WA, USA) between 2011 and 2014 was the largest dam removal project to be completed by that time and has since resulted in major changes to channel dynamics, river substrates, in-stream communities, and the size and shape of the river delta. To assess ecosystem function across the restored Elwha watershed, we compared leaf litter decomposition at twenty sites: 1) four tributary sites not influenced by restoration activities; 2) four river sites downstream of the upper dam (Glines Canyon Dam); 3) four river sites within the footprint of the former Aldwell Reservoir upstream of the lower dam (Elwha Dam); 4) four river sites downstream of the lower dam; and 5) four lentic sites in the newly developing Elwha delta. Three major findings emerged: 1) decomposition rates differed among sections of the Elwha watershed, with slowest decomposition rates at the delta sites and fastest decomposition rates just downstream of the upper dam; 2) aquatic macroinvertebrate communities establishing in leaf litterbags differed significantly among sections of the Elwha watershed; and 3) aquatic fungal communities growing on leaf litter differed significantly among sections. Aquatic macroinvertebrate and fungal diversity were sensitive to differences in canopy cover, water chemistry, and river bottom sediments across sites, with a stronger relationship to elevation for aquatic macroinvertebrates. As the Elwha River undergoes recovery following the massive sediment flows associated with dam removal, we expect to see changes in leaf litter processing dynamics and shifts in litter-dependent decomposer communities (both fungal and invertebrate) involved in this key ecosystem process.

Combination of clinical, radiomic, and "delta" radiomic features in survival prediction of metastatic gastroesophageal adenocarcinoma.

To identify combined clinical, radiomic, and delta-radiomic features in metastatic gastroesophageal adenocarcinomas (GEAs) that may predict survival outcomes. A total of 166 patients with metastatic GEAs on palliative chemotherapy with baseline and treatment/follow-up (8-12 weeks) contrast-enhanced CT were retrospectively identified. Demographic and clinical data were collected. Three-dimensional whole-lesional radiomic analysis was performed on the treatment/follow-up scans. "Delta" radiomic features were calculated based on the change in radiomic parameters compared to the baseline. The univariable analysis (UVA) Cox proportional hazards model was used to select clinical variables predictive of overall survival (OS) and progression-free survival (PFS) (p-value <0.05). The radiomic and "delta" features were then assessed in a multivariable analysis (MVA) Cox model in combination with clinical features identified on UVA. Features with a p-value <0.01 in the MVA models were selected to assess their pairwise correlation. Only non-highly correlated features (Pearson's correlation coefficient <0.7) were included in the final model. Leave-one-out cross-validation method was used, and the 1-year area under the receiver operating characteristic curve (AUC) was calculated for PFS and OS. Of the 166 patients (median age of 59.8 years), 114 (69%) were male, 139 (84%) were non-Asian, and 147 (89%) had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. The median PFS and OS on treatment were 3.6 months (95% CI 2.86, 4.63) and 9 months (95% CI 7.49, 11.04), respectively. On UVA, the number of chemotherapy cycles and number of lesions at the end of treatment were associated with both PFS and OS (p < 0.001). ECOG status was associated with OS (p = 0.0063), but not PFS (p = 0.054). Of the delta-radiomic features, delta conventional HUmin, delta gray-level zone length matrix (GLZLM) GLNU, and delta GLZLM LGZE were incorporated into the model for PFS, and delta shape compacity was incorporated in the model for OS. Of the treatment/follow-up radiomic features, shape compacity and neighborhood gray-level dependence matrix (NGLDM) contrast were used in both models. The combined 1-year AUC (Kaplan-Meier estimator) was 0.82 and 0.81 for PFS and OS, respectively. A combination of clinical, radiomics, and delta-radiomic features may predict PFS and OS in GEAs with reasonable accuracy.

X-Band Radar System to Detect Bathymetric Changes at River Mouths during Storm Surges: A Case Study of the Arno River

Storm surges are natural events that influence the dispersion of sediment along coasts, leading to sudden morphological changes in the seabed. From this perspective, we focused our study on the analysis of measurements from a mobile X-band radar system to survey the sea state and the changes in the seabed depth during storm surges. This analysis was supported by additional information from Sentinel 2 satellite images, the Gorgona wave buoy, the San Giovanni alla Vena hydrometric station, and an echosounder survey. The survey period was from 26 to 28 February and 3 March 2020. During these days, the simultaneous occurrence of a storm surge and flooding of the Arno River was monitored. The analysis of the marine X-band radar mobile images determined the formation and dismantling of seabed shapes. An elongated shoal and a bar-like shape are visible on the right side of the Arno River in the radar image of 26 February and at the Arno mouth on that of 28 February, respectively. The radar image of 3 March shows, near the mouth of the Arno, a delta shape probably due to the deposition of sediment favoured by the interaction between the river flow and storm waves. X-band coastal radar is a detection system that improves the effectiveness and reliability of coastal monitoring because it has a high temporal and spatial resolution. It can be considered a valuable warning system to monitor the sea-bed depth changes in strategic sites, such as harbour areas, during sea storms. Moreover, this system, together with a satellite observing system, is a valid tool for shedding light on the environmental drivers that reshape coastal areas.

Island area changes in the Sundarban region of the abandoned western Ganga–Brahmaputra–Meghna Delta, India and Bangladesh

Delta shapes are governed by relative dominance of wave, tidal, and fluvial processes, while their coastline changes primarily depend on activation and abandonment of distributary channels. The partly-reclaimed Sundarban Mangrove Wetlands occupy the fluvially abandoned western part of the macro-mesotidal Lower Ganga–Brahmaputra–Meghna Delta (GBMD) in India and Bangladesh. To ascertain the evolution of the planform of this 15,500-km2 region over a century, maps and images pertaining to 1904–24 (Survey of India topographical maps), 1967 (Corona space photographs), 2001 (IRS-1D LISS-3 + Pan merged images), and 2015–16 (Resourcesat-2 LISS-4 fmx images) were digitally compared for documenting the changes in the areas of ~250 mangrove-covered and reclaimed tidal islands above the spring high water level. Area change of the individual islands was also studied based on their relative north–south and west–east positions.The results indicated that while erosion of the estuary margins and the sea facing coastline —up to 40 m/yr—was continuing for decades in the southern islands, intervening channels between the northern islands were getting silted up, especially in the western sector, resulting in land gain. Area change in the central sector mostly tended to be small and erosional. Overall, the total island area & counts changed from 11,903 km2 & 253 (1904–24), respectively, through 11,663 km2 & 250 (1967), 11,506 km2 & 244 (2001), and 11,455 km2 & 251 (2015–16). The reduction rate of area, at −4.46 km2/yr, remained noticeably similar across all intervals of mapping / imaging years and projects that the region will lose 3.4 % of its present extent by 2100 if the observed tendencies continue. The trend of area reduction was 2.55-times higher in the western (Indian) segment of the region, than the eastern (Bangladeshi) section. At the level of individual islands, the trends of area change were classified into nine types involving linear and non-linear changes, with dominance of continuous (post-2001) erosion in 48.3 % (68.9 %) of the islands. Conversely, continuous (post-2001) accretion dominates in 15.8 % (31.1 %) of the islands.The retrogradation of the southern Sundarban can be ascribed to sediment starvation of the western GBMD due to abandonment of its deltaic distributaries and shelf bypassing of sediments through the Swatch of No Ground submarine canyon. On the other hand, the accretion of the northern interior areas, especially in the west, was mostly related to sediment reworking in a floodtide dominated environment, intervened by reclamation efforts. Factors like relative sea level rise, locational shifts in landfalls of cyclonic storms, and reclamation-related deforestation had little detectable influence on island area changes. As the observed tendencies of area change are likely to continue, planning for the region must integrate the transformations into management and development initiatives.

Numerical investigation of heat transfer performance of an air heater with delta flow obstruction

Air heaters are a vital component in many engineering systems, including room heating and agricultural dryers. The use of flow obstacles improves the convective heat transfer coefficient by interrupting the formation of a laminar sub-layer. In the previous studies reported, the thermal and frictional effects of various flow obstacle geometries were studied, but they are limited to non-inclined obstacles. The current research examines the thermal and hydraulic characteristics of air heaters with inclined and non-inclined delta shape obstacles using numerical techniques and compares the results with empirical predictions and literature data. The influence of flow rate and angle of attack (α) on Nusselt number (Nu) and friction factor (f) were evaluated using CFD for Reynolds numbers (Re) ranging from 5000 to 20,000 and for α ranging from 300 to 900. A rectangular duct (300 mm × 50 mm) with a constant heat flux of 800 W/m2 at the bottom surface of the air heater with delta obstructions of relative obstacle height (e/H) of 0.5 with a constant transverse (Pt/b) of 1.5 and longitudinal pitch (Pl/e) of 3 was considered. The Nu, f and Thermal Enhancement Factor (TEF) were calculated and investigated for various flow rates and attack angles. The predicted Nu and f values demonstrated a good agreement with empirical correlations, with an average variation of 5.68 percent and 7.2 percent, respectively. The CFD results were also consistent with earlier published experimental findings. The results indicate that using a delta obstruction enhances heat transfer rate considerably at the cost of increased pressure loss. The use of delta-shaped flow obstruction increases Nusselt number in the range of 71–162, with a 6–9.6 times increase in friction factor. A maximum TEF of 1.69 was obtained for the air heater with delta obstruction with α = 300 at Re = 5000.

Seismic performance of cable-stayed bridges with different geometric conditions

Cable-stayed bridges have gained greater coverage in the last few decades. This study focuses mainly on two parameters. Firstly, the shape of pylons; the performance of many shapes is investigated after being exposed to an earthquake. Secondly, the effect of changing deck width of an inverted Y-shaped pylon with variation in main span length. The numerical study was performed using MIDAS civil software. It was concluded that the most efficient pylon shape in terms of seismic performance was that of pyramid shape followed by a delta shape. In addition, it was found that changing deck width for the same main span gives a negligible difference to normalized shear force.

Wave‐Climate Asymmetry Influence on Delta Evolution and River Dynamics

AbstractOn wave‐influenced river deltas, wave‐driven sediment redistribution affects river progradation, and therefore avulsions, while avulsions change where sediment is delivered to the coastline, affecting coastline shape. Coastline shape, in turn, affects sediment redistribution rates and patterns. Here we use a numerical model to investigate how the asymmetry of wave climates affects delta avulsion behaviors, which are coupled with delta shape evolution. Increasing wave‐climate asymmetry tends to reduce (increase) the curvature of updrift (downdrift) delta flanks, by increasing (decreasing) local shoreline diffusivity. In our model experiments, reduced shoreline curvature restricts the possible updrift post‐avulsion river mouth locations, while increased curvature expands the possible downdrift locations, favoring “downdrift avulsions.” However, under some wave climates, local diffusivity on the downdrift flank can become negative, leading to convexity and shoreline accretion, inhibiting downdrift avulsions. Increasing wave heights and decreasing superelevation threshold for avulsions both tend to reduce delta morphologic asymmetry, and therefore avulsion tendency.

Numerical Assessment of a BAY-Type Model for different Vortex Generator Shapes Applied on a Wind Turbine Airfoil

Modern wind turbines are increasingly equipped with vortex generators in the inner part of the rotor blade. On large blades it is usual to install hundreds of these small passive devices to delay flow separation. Therefore, affordable numerical methods to include vortex generators in the design process are required. One very promising method based on the addition of source terms in the flow equations is the BAY model. In this work a BAY-type model is presented and assessed for three different vortex generator shapes (rectangular, delta and cropped-delta) placed on a DU 97-W-300 airfoil and computed with steady-state Reynolds-averaged Navier-Stokes numerical methods. In order to quantify the circulation of the main streamwise vortex, a method to identify the vortex core based on the λ2-criterion is presented and shows good results. The computations reveal very good agreement with the experimental data for attached flow in terms of lift and pressure distribution while drag is inherently underestimated by the BAY model due to the inviscid modelling of the vortex generators. It is displayed that this underestimation is proportional to the vortex generator surface area. Concerning the different shapes, it is shown that the delta shape reveals larger deviations from the fully resolved case than the other geometries and therefore requires higher mesh resolution.

Explainable Boosting Machine Model with a Parallel Ensemble Design Predicts Local Failure for Head and Neck Cancer With Clinical, CT, and Delta CBCT Radiomic Features

Local failure (LF) following chemoradiation for head and neck squamous cell carcinoma (HNSCC) is associated with poor overall survival. If machine learning techniques could stratify patients at risk of treatment failure based on baseline and intra-treatment imaging, such a model could facilitate response-adapted approaches to escalate, de-escalate, or switch therapy. Our hypothesis was that adding baseline CT (CT1) and delta CBCT radiomic features to a clinical model would improve its discriminatory ability at predicting LF.Participants treated at a single institution with definitive radiotherapy (RT) for HNSCC and who failed locally in-field at a primary or nodal structure (analyzed separately) were included and matched to controls (30 cases, 60 controls) based on the site of primary, T/N stage, and p16 status. Radiomic features were extracted from CT1 and CBCT scans at fractions 1 (CBCT01) and 21 (CBCT21; where CBCT21 - CBCT01 = delta features) of RT with open-source software and were selected for by: reproducibility (intra-class correlation coefficients < 0.95), redundancy (maximal relevance and minimal redundancy), and informativeness (recursive feature elimination). Separate models predicting LF of primaries or nodes were created using the explainable boosting machine classifier with 5-fold cross-validation for (1) clinical only, (2) radiomic only (CT1 and delta features), and (3) fused models (clinical and radiomic models fused). Twenty-five iterations were performed and predicted scores were averaged with a parallel ensemble design. Receiver operating characteristic (ROC) curves were compared against each other with paired-samples T tests in a statistical software with the ROC analysis function.The fused ensemble model for primaries achieved an area under the curve (AUC) of 0.871 with a sensitivity of 78.3% and specificity of 90.9% at the maximum Youden J statistic, which trended towards improvement when compared to the clinical (AUC = 0.788, P = 0.134) but only reached significance when compared to the radiomic ensemble model (AUC = 0.770, P = 0.017). For nodes, the fused ensemble model achieved an AUC of 0.910 with a sensitivity of 100.0% and specificity of 68.0%, which also trended towards improvement when compared to the clinical model (AUC = 0.865, P = 0.080) but did not reach significance. The most commonly included radiomic features in the ensemble were delta shape features, with change in maximum 3D diameter and change in sphericity being the most common for the primary (69.6%) and nodal (80.8%) models.The fused ensemble explainable boosting machine model achieved high discriminatory ability at predicting LF of HNSCC in independent primary and nodal structures. Although an additive benefit of delta radiomics over clinical factors could not be proven, the results trended towards improvement with the fused ensemble model, which are promising and worthy of further investigation in a larger cohort.

The “striated delta” signature of gravity waves generated near the jet stream during rapid extratropical cyclogenesis

AbstractDistinctive, triangular‐shaped “striated delta” clouds provide a novel framework for better understanding large‐amplitude gravity wave generation near upper‐tropospheric jets and fronts during rapid extratropical cyclogenesis, as the transverse cloud‐top banding is thought to be the imprint of gravity waves. For 28 striated deltas in the Australian region between May and September 2009, cloud formations have a mean length of 1,034 km, width of 537 km, lifetime of 7 hr and striation wavelength of 74 km. Composite analysis in ECMWF operational analysis data shows that deltas typically occur within the poleward jet exit during baroclinic evolution, located near the axis of inflection between an upstream upper trough and downstream ridge. Candidate gravity wave generation mechanisms in the vicinity of the upper jet coinciding with striated delta development are examined, including large parcel accelerations, nonlinear imbalance within the broadscale flow and deep moist convection. The striated delta shape is partly explained by a triangular pattern of Q‐vector convergence and quasi‐geostrophic adiabatic vertical motion forcing within the poleward jet exit, although the pattern is displaced a few hundred kilometres upstream.

Verification of SIMPACK-MoorDyn coupling using 15 MW IEA-Wind reference models Activefloat and WindCrete

The modelling of mooring lines and their behaviour is essential for the research and development of Floating Offshore Wind Turbines (FOWTs). Mooring lines’ dynamics impact the platform motions and hence the loads on the turbine’s blades. Therefore, coupling the mooring lines’ dynamics in the aero-hydro-servo-elastic models is a necessity. In this paper we couple Moordyn to SIMPACK which is a multibody system simulation software. Afterwards, we verify the coupling by comparing the results to OpenFAST v2.1. The IEA Wind 15 MW reference wind turbine coupled to Activefloat and WindCrete floaters, introduced in COREWIND project, are used for the verification process. The two floaters have two different mooring configurations; WindCrete is a spar floater with a symmetric delta shape catenary mooring line system, while Activefloat is a semi-submersible with simple catenary mooring configurations. During the verification, both steady and dynamic load cases are used for the responses of two mooring systems. After the verification, the coupling procedure is open access and can be used to model new innovations in FOWTs using SIMPACK benefiting from the tool’s flexibility.

An Insight to the Sedimentological Developments of Quaternary Detritus Ring Fluvial Network, Altun Kupri Paleolake, NE IRAQ

During the Quaternary, an active basin in the shape of open lake originated along the Lesser Zab river at Altun Kupri area. The radial complex of fluvial deposit morphologically initiated by the coarse detritus material, that were transported by the Lesser Zab river and other surrounded valleys in a shape of delta towards the proximal part of coastal plain and the fine sediment to the distal part of it. The coarse one prograde along the fine gradually resulting in the accumulation of about 60 m thickness of continuous Pleistocene fluvial succession mostly of coarse grained sediments with minor sand, silt and clay intervals and some tongues and bands of calcareous mud. The bulk of basin fill is made of two depositional systems, the western and southwestern side was filled up by progradation delta systems, but the northern side was gradually filled up by fluvial sediment of Lesser Zab channel. The water impounded in this lake because of Awanah anticline as a ridge in front of the lake which is open with output channel that crosses the shallow gorge and the gorge became deeper and deeper gradually till the water drooped from the lake. There are several possibilities that this ring shape depression of Altun Kupri paleolake generated, first: the depression at Altun Kupri is formed as a result of dissolving lenses of Anhydrite and gypsum of the Fat’ha Formation beneath the northern limb of Awanah Anticline after the collapse of the cavity roof. second: the presence of ring shape cliffs of about 50m thick and depression is bounded by 8km in diameter of cross bedded conglomerates and sandstone and the third: the depression of Altun Kupri paleolake can be developed by meteoritic impact, with several sedimentological and structural evidence such as a delta distributary fan, and there was a hanging terrace at a high level along the gorge

Higher-order particle representation for particle-in-cell simulations

In this paper we present an alternative approach to the representation of simulation particles for unstructured electrostatic and electromagnetic PIC simulations. In our modified PIC algorithm we represent particles as having a smooth shape function limited by some specified finite radius, r0. A unique feature of our approach is the representation of this shape by surrounding simulation particles with a set of virtual particles with delta shape, with fixed offsets and weights derived from Gaussian quadrature rules and the value of r0. As the virtual particles are purely computational, they provide the additional benefit of increasing the arithmetic intensity of traditionally memory bound particle kernels. The modified algorithm is implemented within Sandia National Laboratories' unstructured EMPIRE-PIC code, for electrostatic and electromagnetic simulations, using periodic boundary conditions. We show results for a representative set of benchmark problems, including electron orbit, a transverse electromagnetic wave propagating through a plasma, numerical heating, and a plasma slab expansion. Good error reduction across all of the chosen problems is achieved as the particles are made progressively smoother, with the optimal particle radius appearing to be problem-dependent.

Motion behavior of micro-bubbles in a delta shape tundish using impact pad

Micro-bubbles were generated using gas injection through tiny orifices located at the upper part of the ladle shroud, for deep cleaning the liquid steel. An impact pad was employed to improve the dispersion of micro-bubbles in the liquid bath, reduce the collision between bubbles, as well as to achieve the conventional functions of a turbulent inhibitor. A 3-D numerical modeling was developed to predict the flow characteristics and bubble motion behaviors under the effect of the impact pad, with the bubble sizes obtained from the measurements in full-scale water experiments. For comparison, the corresponding numerical simulation was also carried out in the tundish with a conventional turbulent inhibitor. It was found that the impact pad promotes the spreading of micro-bubbles in the tundish bath, which could effectively reduce the coalescence of bubbles, so as to restrain the secondary bubble grow-up. The global efficiency of inclusion removal by bubble flotation was evaluated, considering the mechanism of repeated bubble sweeps in each element. The inclusion removal was raised by 14.33–37.09% due to the extended area of bubbles dispersion, even with the same bubble amount and size.

Binary tomography on the isometric tessellation involving pixel shape orientation

In this study, a tomography reconstruction problem of binary images is considered on the isometric grid. On this grid, the triangle pixels have two types of orientations, accordingly, the authors call them delta or nabla shape pixels. The proposed reconstruction method uses data of projections of three natural directions. They are the lane directions of the triangular tessellation (these directions are somewhat analogous to row/column directions on the rectangular grids). The projection ray, penetrating through a grid lane, now not passing through the middle of pixels (i.e. through the middle line of triangle shape pixels), as usually taken, but little bit shifted from the middle parallel to the lane. This method provides the exact information about the number of nabla and delta shape triangle pixels in each lane of the image. This additional information is included in the reconstruction process to improve the quality of reconstruction. They formulate the suggested model into an energy-minimisation problem and apply a gradient-based approach for its minimisation. They show and analyse various experimental results on test images. The presented approach shows both better quality reconstructions and shorter running time than the earlier approaches.

Design of an Aircraft Wing Structure for Static&amp; Fatigue Life Prediction

A wing is a type of blade with a ground that produces streamlined power for flight or strain via the surroundings, (o r) through every other vaporous or fluid liquid. In that potential, wings have an airfoil form, a streamlined pass-sectional form handing over carry. A wing's streamlined e satisfactory is communicated as its increase-to-drag percentage. The increase a wing creates at a given velocity and approach may be one to 2 units of quantity extra fantastic than the absolute delay the wing. A excessive convey-to-drag percentage calls for an altogether littler push to pressure the wings through the air at true sufficient raise. The conditions for the air deliver wing are excessive firmness, high extremely good, high durability and occasional weight. In shape and constrained issue research of flying system wing is planned and confirmed in three-d displaying programming CATIA. The wing is altered with the aid of manner of 3 noteworthy arrangement structure geometries figuring out with decrease share are rectangular, trapezoidal and delta shape. to be able to assemble the great of the wing Trapezoidal maximum ideal for out of 3 shapes. So Trapezoidal form air uniqueness wing is applied in those art work. in this the NACA-4 digit affiliation is carried out for making wing skeleton form and later we made showing, Fatigue and auxiliary research on wing Skelton structure by way of using ANSYS paintings BENCH. The substances applied for air deliver wings are for the maximum factor steel mixtures. on this postulation, the substances are supplanted via composite materials S2 Glass and Kevlar 40 nine. Static examination is completed to determine the distortion ,stresses and lines added by means of making use of loads. weak spot exam to appraise the existence ,harm and well being component of the wing. Modular examination is completed on the air deliver wing to decide the misshapenings and frequencies, worry because of frequencies. investigation is completed in ANSYS.

Reservoir deltas and their role in pollutant distribution in valley-type dam reservoirs: Les Království Dam, Elbe River, Czech Republic

Interpretation of catchment pollution history from sediment cores is a common approach for dam reservoirs, but relatively little is known about the spatial distribution of pollutants in the lithologically diverse depositional subsystems. We studied the depositional system of a hundred-year-old valley-type reservoir of the Les Království Dam built in 1919 on the upper reaches of the Elbe River, Czechia. Based on the analysis of pre-dam river valley morphology using historical topography maps with 1 m vertical resolution, 30 ground-penetrating radar sections on the lake and 137Cs dating of four cores, we described a deltaic sediment body with maximum thickness of ~11 m, accumulation rates ranging from 3.6 to 9.7 cm/yr, and an annual loss in reservoir capacity of 0.8%. The sediment body has a distinct delta shape in the longitudinal section, with a delta platform dissected by a channel (topsets) and delta slope (foresets) and a ponded basin (bottomsets) located near the dam. The upstream sections of the channels are prone to erosion and sediment redistribution into downstream parts of the reservoir, as indicated by ground-penetrating radar sections and distribution of 137Cs in younger sediment strata.We retrieved four cores 1.0 to 1.6 m long from different parts of the delta and analysed the sediment grain size using laser granulometry, geochemical composition (X-ray fluorescence, ICP-MS lithogeochemistry, total organic carbon (TOC)) and concentrations of polycyclic aromatic hydrocarbons (PAH). The grain size variation between the delta platform (sandy silts and silty sands) and prodelta (clayey silts) sediments strongly controls the concentrations of lithogenic elements (Al, Fe, K and Ti) but it has a relatively little effect on distribution of toxic metals (Zn, Cu, Pb) and TOC concentrations. The toxic metals show strong affinity to TOC and PAH show a distinct sawtooth vertical distribution suggesting that they were deposited from depositional events during hyperpycnal flows induced by river floods. This study shows that a hyperpycnal delta may serve as a good predicable model for toxic metal- and organic pollutant distribution in dam reservoirs. The role of hyperpycnal flows should not be overlooked in contamination studies of dam reservoirs.