Wide Belt Research Articles

Effect of an abdominal binder on postoperative outcomes after ventral hernia repair: a systematic review and meta-analysis of randomized controlled trials.

Abdominal binders consist of a wide compression belt that encircles the abdomen, theoretically supporting the abdominal wall. However, their use after ventral hernia repair is debated. Therefore, this meta-analysis evaluates their efficacy. We searched PubMed, Embase, and Cochrane Central for randomized controlled trials (RCTs) comparing the effects of abdominal binders after ventral hernia repair. Outcomes included postoperative pain using the visual analog scale (VAS), surgical site infection (SSI), seroma formation and size, general well-being, activity limitation, forced expiratory volume in the first second (FEV1), and a 6-min walk test. Statistical analysis was performed with Review Manager 5.4.1 using a random-effects model. We included five RCTs encompassing 297 patients. Overall analysis showed decreased SSI rates (RR 0.21; 95% CI 0.07 to 0.59; p = 0.003; I2 = 0%) and reduced pain two weeks after surgery (MD -0.89; 95% CI -1.41 to -0.37; p = 0.0008; I2 = 0%) using abdominal binders. For patients undergoing open ventral hernia repair, it also demonstrated reduced SSI, pain four weeks after surgery (MD -0.60; 95% CI -0.88 to -0.32; p < 0.0001; I2 = 66%) and increased 6-min walk test performance four weeks after the procedure (MD 32.78m; 95% CI 15.28 to 50.29m; p = 0.0002; I2 = 0%). Abdominal binders may decrease SSI, postoperative pain, and increase physical condition, particularly in open ventral hernia repair. Further studies are still required to evaluate the role of abdominal binders in minimally invasive techniques.

Architecture and geomorphology of fluvial channel systems in the Arabian Basin

The architecture and geomorphology of fluvial channel system plays an important role in the interpretation of its sedimentary processes and characterization of the ability for subsurface storage. In the Arabian Basin, this system is considered a new petroleum play after a century of carbonate-play dominance with enormous petroleum reserves. In addition, the presence of publicly available 3D seismic refection data in the Arabian Basin is very limited, providing a condition that fluvial channel system knowledge becomes publicly less understood. Therefore, our study utilizes 3D seismic reflection data and aims to (1) interpret seismic facies and architecture, (2) map the unit thickness and lateral distribution, and (3) calculate morphometry of the Late Carboniferous to Early Permian fluvial channel systems in the Arabian Basin, and discuss its sedimentary processes, development and petroleum prospectivity. Seismic facies and seismic attribute analysis revealed three distinct fluvial channel systems including their crevasse-splay and flood plain. The channels are characterized by isolated bright on the RMS amplitudes, spectral decomposition, variance and sweetness with sinuous geomorphology and lobes (crevasse-splay) and variation of amplitude values in hummocky to sub-parallel and parallel (flood plain) reflection configuration. The morphometric analysis shows three clusters on the scaling relationship between maximum channel width and meander belt width, as well as the minor variation on the channel sinuosity index. These results indicated the dominance of the bed-load sediment transport mechanism in the fluvial depositional environment with a single-story channel body architecture. These factors provide the ability for fluvial channel systems in the studied area to act as petroleum reservoir as well as potential source rock, cap rock and stratigraphic traps. Furthermore, a single-story channel body indicated poorly connected among them, both in lateral and vertical extends that required horizontal wellbore for drainage the reservoir. Our study revealed that fluvial channel systems in the Arabian Basin has potentiality both in petroleum prospectivity as well as subsurface storage (carbon dioxide, waste, hydrogen). In addition, the workflow presented here could be applicable to characterize the fluvial channel system from 3D seismic reflection data in other basins, worldwide.

"The Neon Dress Drags a Wide Belt, Fluttering to Heaven"

This paper deeply analyzes the artistic characteristics of the dance "Flying Sky". By exploring its unique historical origin, movement vocabulary, dance design and the inheritance and development of skills, it shows how the work skillfully integrates classical beauty and modern aesthetics, vividly interprets the elegance and dexterity of the flying sky myth, and conveys profound cultural connotation and artistic charm.

Bamboo belts with variable fiber cell angles for winding applications: Development of a novel manufacturing technique and assessment of performance feasibility

In response to the environmental impacts of synthetic fiber production and disposal, coupled with limitations in the existing continuous processing methods for plant fibers, this study proposed a novel manufacturing approach for preparing wide and continuous bamboo winding belts. The current application scenarios of bamboo belt winding products are limited because the reinforcement orientation cannot be optimized due to the inherent stiffness of bamboo belts, and the variety of bamboo belt types is limited. This study employed two representative types of bamboo belts: bamboo slivers and thin bamboo veneers, which had varying cross-sectional aspect ratios. Verification demonstrated that this method enabled the production of bamboo winding products with any reinforcement orientations ranging from 0 radians to π radians. This addressed the challenge of optimizing reinforcement orientation in bamboo winding products and was anticipated to broaden the application of this method to other winding units with unidirectional reinforcement. Additionally, the performance feasibility of the two bamboo winding belts prepared using this method was evaluated in terms of microstructure, surface wettability, and mechanical properties. The bamboo slivers and thin bamboo veneers, with their rigid-flexible structure, hydrophilicity, and non-catastrophic fracture characteristics, enhanced their winding potential. These wide, continuous, and rigid-flexible features of the bamboo winding belts held promise for their expanded applications in bamboo winding products, thus promoting sustainable and environmentally friendly manufacturing practices.

Spatio-temporal migratory patterns, habitat crossing and within-individual movement repeatability of Central Mediterranean European Rollers Coracias garrulus

Populations of long-distance migratory species may exhibit dissimilarities in the leeway of scheduled annual migration programs, the routes they follow and their convergence at ecological barriers. The aim of this study was to fill the current geographical gap, spanning over 1,100 km longitudinally between southern France and eastern Austria, in the pan-European assessment of the migration ecology of the European Roller Coracias garrulus, and contribute to completing the puzzle of spatio-temporal patterns of migration, stopover and wintering at the Western-Palearctic scale for this species. We utilized high-resolution GPS tracking data from adult Rollers breeding in Italy and Croatia, tracked on their intercontinental seasonal journeys between 2018 and 2022 and modelled the variation of migratory components both at individual and population levels. Rollers from the Central Mediterranean exhibited a clockwise spring migration loop, following a Central African migration route and wintering across a wide longitudinal belt spanning from Namibia to Mozambique. Northern savannah zones were used as long stopovers, both in autumn (Chad/Sudan) and spring (Central African Republic/Cameroon). The probability of movement was significantly higher during the night and in spring. Migration speed varied according to season (> in spring) and the habitat crossed (sea > desert > rainforest > savannah). Individuals tracked in successive years showed high consistency of key migratory parameters and partial winter home ranges overlap, in contrast with the large variability of migratory parameters at the population level. This work bridges the current geographical gap of Roller migration ecology at the European level and helps meet conservation needs at the scale of the species’ flyway, with new ecological information valuable for the implementation of International Single Species Action Plans (ISSAP) dedicated to the Roller.Significance statementTracking studies help to disentangle intraspecific variation in migratory strategies and wintering destinations among populations, as well as investigate individual-level decisions taken en route across seasonal journeys. By GPS tracking the intercontinental migration of adult Rollers we found that spatio-temporal components of migratory and flight strategy largely depend on extrinsic factors such as daytime, season and the habitat they traversed, and vary at population level. In contrast, within-individual consistency in migratory and wintering patterns emerged across years. Our findings emphasize the need for effective conservation strategies at the flyway scale.

MORPHOMETRIC CHARACTERISTICS OF THE MEANDERS OF THE DNIESTER ON THE PODILIA

The purpose of the work is to determine the exact number of formed meanders on the Podilia part of the Dniester, to provide them with the most complete morphometric characteristics, to separate them into separate groups according to the available morphometric data and territorial proximity. Morphometric characteristics of meanders is an important initial stage of their research. With the help of the Google Earth application, cartographic and generally descriptive methods, 30 separate meanders on the Dniester have been identified. To provide a complete morphometric characteristic of each meander, the following parameters were used in the work - the length of the meander in the circuit, the length of the meandering direction, the length and width of the meandering belt of adjacent meanders, the width of the meander deflection, the radius of curvature of the meander, the curvature of the meander bed and the shape of the meander. Each meander is given a separate name in order to distinguish it from other meanders and to use this name in subsequent works. The names of the meanders coincide with the corresponding name of the locality, which is located closest to the top of the meander. Each name of the meander is the author's and does not always coincide with the names given to them by previous researchers. In the work, detailed attention is paid to the presence or absence of tributaries of the Dniester near the windings. After all, this may indicate active neotectonic movements in this area and help determine the genesis of meanders. Separate large groups of meanders have been identified on the basis of available data - detailed morphometric characteristics and the presence of adjacent meanders in separate territories. It is also worth noting that in the last century such well-known scientists as Oleksandr Marynych and Kalenyk Gerenchuk [6] already carried out the zoning of the Dniester meanders. Everyone used their own methods, so the number of groups of meanders of the Dniester was different for everyone. The work also presents drawings depicting the largest meanders on the Dniester. Using the determined morphometric data, the largest and smallest meanders, the largest belts of meanders, compared different meanders with each other, determined the degree of meandering of the river in these areas, and also expressed the most probable reasons that influenced the development of this kind of meanders. Key words: meanders of the Dniester, morphometry, Podillia, morphometric characteristics of meanders.

Scour-depth variability controls channel-scale stratigraphy in experimental braided rivers

ABSTRACT Braided rivers distribute sediment across landscapes, often forming wide channel belts that are preserved in stratigraphy as coarse-grained deposits. Theoretical work has established quantitative links between the depth distribution of formative channels in a braided river and the geometry of their preserved strata. However, testing these predictive relationships between geomorphic process and stratigraphic product requires examining how braided rivers and their deposits coevolve, with high resolution in both space and time. Here, using a series of four runs of a physical experiment, we examine the controls of water discharge and slope on the resulting geometry of preserved deposits. Specifically, we focus on how a twofold variation in water discharge and initial riverbed slope affects the spatiotemporal distribution of channel depths and the geometry of preserved deposits of a braided river. We find that the channel depths in the laboratory experiment are described by a two-parameter gamma distribution and the deepest scours correspond to zones of erosion at channel-belt margins and channel-thread confluences in the channel belt. We use a reduced-complexity flow model to reconstruct flow depths, which were shallower compared to channel thalweg depths. Synthetic stratigraphy built from timeseries of topographic surfaces shows that the distribution of cut-and-fill-unit thickness is invariant across the experiments and is determined by the variability in scour depths. We show that the distribution of cut-and-fill-unit thickness can be used to reconstruct formative-channel-depth distributions and that the mean thickness of these units is 0.31 to 0.62 times the mean formative flow depth across all experiments. Our results suggest that variations in discharge and slope do not translate to measurable differences in preserved cut-and-fill-unit thickness, suggesting that changes in external forcings are likely to be preserved in braided river deposits only when they exceed a certain threshold of change.

Dengue: A review of laboratory diagnostics in the vaccine age

Background. Dengue is an important arboviral infection of considerable public health significance. It occurs in a wide global belt within a variety of tropical regions. The timely laboratory diagnosis of Dengue infection is critical to inform both clinical management and an appropriate public health response. Vaccination against Dengue virus is being introduced in some areas. Discussion. Appropriate diagnostic strategies will vary between laboratories depending on the available resources and skills. Diagnostic methods available include viral culture, the serological detection of Dengue-specific antibodies in using enzyme immunoassays (EIAs), microsphere immunoassays, haemagglutination inhibition or in lateral flow point of care tests. The results of antibody tests may be influenced by prior vaccination and exposure to other flaviviruses. The detection of non-structural protein 1 in serum (NS1) has improved the early diagnosis of Dengue and is available in point-of-care assays in addition to EIAs. Direct detection of viral RNA from blood by PCR is more sensitive than NS1 antigen detection but requires molecular skills and resources. An increasing variety of isothermal nucleic acid detection methods are in development. Timing of specimen collection and choice of test is critical to optimize diagnostic accuracy. Metagenomics and the direct detection by sequencing of viral RNA from blood offers the ability to rapidly type isolates for epidemiologic purposes. Conclusion. The impact of vaccination on immune response must be recognized as it will impact test interpretation and diagnostic algorithms.

Distribution pattern of large old Ginkgo biloba in China under climate change scenarios.

Large old Ginkgo biloba trees (LOGTs), with profound ecological and cultural significance in China, face increasing threats from climate change and human activities. We employed the BIOCLIM and DOMAIN species distribution models to predict their spatial patterns under the present climate and doubled-CO2 climate change scenario in 2100. We collected 604 validated LOGT occurrence records and data on 19 bioclimate factors for the analysis. Our study yielded a LOGT geographic distribution pattern covering a wide latitudinal belt extending from south subtropical to temperate zones in central and eastern China, concentrating in low elevations and coastal regions. The principal component analysis identified the dominant bioclimatic factors shaping their distribution, namely annual precipitation and low winter temperatures. BIOCLIM and DOMAIN generated predicted suitable habitats that match the present distribution range well. However, under the future climate scenario, the models indicated habitat retentions mainly in the core distribution areas and habitat losses mainly in the southern edge of the present range and scattered pockets elsewhere. Some retained habitats, including excellent ones, will suffer from fragmentation. The predicted new habitats may permit some range expansion and migration but are beset by small patch size and large interpatch distance, bringing fragmentation and gene flow restrictions. The anticipated projected range decline highlights considerable threats climate change poses to the long-term survival of the precious natural-cum-cultural resource. Understanding the distribution patterns and underlying drivers and distillation of practical conservation measures can foster sustainable management vis-a-vis the looming global change.

Petrology and Geochemistry of the Ultramafic Rocks of Yerrabali Schist Belt, Eastern Dharwar Craton, Telangana, India

Abstract The Yerrabali schist Belt (YSB) is a NW–SE trending 10 km long and 4 km wide belt located at the north eastern corner of Eastern Dharwar Craton (EDC) consisting of Banded Magnetite Quartzite (BMQ), ultramafic rocks, quartz–cordierite– gedrite ± garnet bearing schist, sillimanite–garnet–cordierite schist, metadolomite, amphibolite, ferruginous quartzite, tremolite schist and dolerite dyke. The ultramafic rocks consist of olivine, orthopyroxene, clinopyroxene and spinel. The Fe content of olivine varies from 88-91 and consists of high amount of NiO (0.3-0.511%). Orthopyroxone are enstatitic and clinopyroxene are Mg-augite in nature. The spinel grains are rich in Al2O3 (48.32-59.09%) and show very low Cr# values (0.08-0.29). Thermo-barometric analyses show equilibrium condition of 700°-1100°C temperature and 19-21 kb pressure. Oxygen fugacity of the ultramafic rocks range from -0.035 to -1.356 log units below FMQ buffer. Low Cr# values of spinel along with low oxygen fugacity suggest their formation by low degrees of partial melting from a less refractory Mid Oceanic Ridge (MOR) type mantle.

CFD-DEM-based evaluation of main-channel sediment transport processes subject to supplement from a steep tributary

The accumulation of sediments within mountainous gullies serves as a significant source for the main channel. Understanding the transport characteristics is crucial for comprehending reach-scale sediment supply features and channel morphodynamics. This study addresses the previously unexplored challenges in accurately quantifying variations in sediment transport rates, particularly during critical transitions such as the mobilization of static sediment pulses into continuous motion. To accomplish this objective, a combined Computational Fluid Dynamics and Discrete Element Method (CFD-DEM) computational framework is employed to directly simulate the detailed trajectories of all particles. After validating the CFD-DEM model, we examine the effects of three major influential factors (particle size, channel slope and channel width) on sediment transport characteristics. The results indicate that the sediment transport rate exhibits rapid rise to peak followed by gradual attenuation process, described by a long-tail effect. The cross-sectional averaged sediment transport rate positively correlates with the width of sediment transport belt. The downstream propagation of sediment is enhanced by steeper channel slope and narrower channel width. In addition, we find that cross-sectional averaged sediment transport rate controlled by these factors exhibits inherent self-similarity. The temporal variation of dimensionless sediment transport rate for a certain section can be modeled by a modified two-branch Weibull function encompasses three model parameters dependent on influential factors and longitudinal location. The parameter variation of the functional model, combined with linear variation of the three main influencing factors, provides support for explaining sediment transport processes in channels of dimensions different from those studied. These findings enhance the understanding of the formation and evolution mechanism of sediment transport induced by upstream loose deposit destruction.

Meander Morphologic Characteristics in an Alluvial Channel

Meander bends are one of the most common morphological features of rivers. Their formation is the result of interactions between bank erosion and several other river characteristics, such as the bed topography resulting from bank erosion, sinuosity, channel flow, and riffle-pool sequencing. Many studies have emphasized proportional relationships between channel widths and different aspects of meander morphology, such as wavelength, curvature of the radius, and belt width. These relationships have been studied for bankfull level width in high-order channels. It is not clear how such relationships vary in low-order headwater streams. This research addresses those gaps in low-order streams of which little is known. Field surveys were conducted in nine meander bends of a low-order alluvial channel in Virginia. The results suggest that in a low-order channel, the ratios of width with wavelength, the radius of curvature, and belt width are mostly similar between the meanders’ beginning and tail endpoints. The stream also has similar meander morphologic characteristics and ratios as anticipated from the literature on high-order streams.

Effects of the abdominal belt on the reduction of spinal forces and muscle activities during extreme transits of high-speed craft

Repeated high-g shocks and whole-body vibration (WBV) as experienced by operators of High-Speed Craft (HSC) increase the risk of fatigue, back pain, and acute and chronic injuries, especially in the lumbar region of the spine. Studies on abdominal belts have suggested their beneficial effects on lumbar torso stabilisation and back pain mitigation in both weight lifting and HSC scenarios. This paper presents a human musculoskeletal model to simulate belt effects for occupants on HSC under high-g shocks. Parameters included the shock severity with peak acceleration ranging from 3 g to 10 g, human dimensions and muscle strengths, the belt width and belt forces are investigated. The results show an average of 120% increase in the intra-abdominal pressure (IAP), a 9% reduction in the transverse abdominis activities, and a 12% reduction in the spinal compressive force at the L4/L5 joints when the abdominal belt is added to the human model. In conclusion, wearing an abdominal belt significantly assists abdominal muscles and maintains a solid core during intense WBV generated in different shock severity levels. It may cause a small negative influence on the neck region with a 2.4% increase in the shear force at the C4/C5 joints.

ТЕОРЕТИЧЕСКОЕ ОБОСНОВАНИЕ ТРАНСПОРТЕРА ДЛЯ ВЫГРУЗКИ КОРНЕПЛОДОВ ОВОЩНЫХ КУЛЬТУР И КЛУБНЕЙ КАРТОФЕЛЯ ИЗ ХРАНИЛИЩА

The need to develop specialized machines and equipment for laboratory and field research on potato breeding is due to the fact that the methodology of breeding processes and the first stages of seed production involves comparing many plants of different origins and selecting the best for further work up to the creation of a new variety or transfer of seeds for propagation in production conditions. The large variability of machines for unloading vegetables and potatoes does not adequately prevent damage to vegetable and potato products, which is due to the imperfect design of such machines, including the imperfection or absence of patterns of automated control of the technological process of work and justification of the parameters of their working parts. The purpose of the study is to substantiate the parameters of the conveyor for unloading vegetable crops and potatoes into storage and to determine the patterns of formation of the control signal of the transfer function of automatic control of operation. The power required to move the pick-up depends on the maximum pressure force of introducing the intake element into the embankment, the mass of the pick-up and the rolling resistance coefficients of the running wheels of the pick-up and transport sections. The length of the unloading conveyor of the machine is determined by the reserve zone to prevent wheels from hitting the tubers, their maximum difference in the embankment, the height of the layer, as well as the angle of inclination of the unloading conveyor. The width of the conveyor belt for unloading products from storage is determined by the values of the coefficient of friction of root crops on the surface of the belt, the coefficient of working time utilization and the forward speed of the conveyor belt. After removing the collapsed mass of tubers, the line of crumbling slopes and the limiting equilibrium are a straight line, characterized by an empirical equation for determining the coordinates of the tuber collapse point, the height of the tuber layer and the embankment collapse coefficient. When the feeder tubers are introduced into the surface of the embankment, the formation of slopes occurs in four stages: the formation of a natural slope, a limiting equilibrium slope, a shedding slope and a product collapse slope.

Preliminary Study on Floral Distribution, Abundance and Diversity of Mangroves in Vankalai, North-west Coast of Sri Lanka

Sri Lanka harbors a remarkable amount of mangrove habitats. Northern Province shares about 16% of the total mangrove extent of the country. Vankalai consists of several ecosystems which range from arid-zone thorn scrubland, arid-zone pastures and maritime grasslands, sand dunes, mangroves, salt marshes, lagoons, tidal flats, sea-grass beds and shallow marine areas. Due to the integrated nature of shallow wetland and terrestrial coastal habitats, this sanctuary is highly productive, supporting high ecosystem and species diversity. The research was aimed to identify the distribution, abundance and diversity of mangroves in Vankalai of the Northern Province, Sri Lanka. Ten 25m wide belt transects with 10m intervals were randomly arranged in the small patch of mangrove vegetation perpendicular to the 350m of shoreline across the water-land gradient. Each transect was divided into five 5mx5m subplots for convenience of sampling. True mangrove species in each transect were identified and counted. The quantitative data has been used to compute the Shannon diversity index (H), Simpson Index (D) and Shannon Evenness (E), which were used to compare the diversity of the study sites. Ten different mangrove species including Avicennia marina (n=115), Avicennia officinalis (n=73), Rhizophora apiculate (n=33), Rhizophora mucronata (n=102), Sonneratia alba (n=3), Pemphis acidula (n=4), Excoecaria agallocha (n=40), Lumnitzera racemose (n=91), Bruguiera cylindrical (n=97), Ceriops tagal (n=31) were identified and they were belonging to five families; Avicenniaceae (n=2), Rhizophoraceae (n=5), Lythraceae (n=1), Euphorbiaceae (n=1) and Combretaceae (n=1). Further, based on the IUCN status, two mangrove species (Sonneratia alba and Bruguiera cylindrical) were identified as endangered species. The highest Shannon diversity index (H=2.21) and the lowest Simpson index value (D=0.14) were observed in the transects of point 1 due to minimal disturbances. The least Shannon diversity index and evenness were recorded in the point 5 as 1.65 and 0.85 respectively at the point 5 since fishing and tourism activities take place in the proximity of this place. The Shannon diversity index varied at the points of 1 (H=2.21)&gt;2 (H=2.10)&gt;3 (H=1.89)&gt;4 (H=1.84)&gt;5 (H=1.65) whereas Simpson index value were varied at the points of 1 (D=0.14)&lt;2 (D=0.17)&lt;3,4 (D=0.18)&lt;5 (D=0.19) respectively. Pollution and human interaction would have degraded the environmental quality of the mangrove habitats. Based on the observations it was found that the extent of disturbances was minimum at the points of 1 and 2 whereas anthropogenic influence was increased at the points of 3&lt;4&lt;5 respectively. Further, use of mangrove poles and sticks to build fish baits and fishing rods by the anglers could possibly destroy these small patches of mangroves. Hence, actions should be taken for conservation of existing patch and replenishment of new mangroves. &#x0D; Keywords: Mangroves, Diversity, Shannon Diversity Index (H), Simpson Index (D) and Shannon Evenness (E)

Timescale of the Morphodynamic Feedback Between Planform Geometry and Lateral Migration of Meandering Rivers

AbstractAcross varied environments, meandering channels evolve through a common morphodynamic feedback: the sinuous channel shape causes spatial variations in boundary shear stress, which cause lateral migration rates to vary along a meander bend and change the shape of the channel. This feedback is embedded in all conceptual models of meandering channel migration, and in numerical models, it occurs over an explicit timescale (i.e., the model time step). However, the sensitivity of modeled channel trajectory to the time step is unknown. In numerical experiments using a curvature‐driven model of channel migration, we find that channel trajectories are consistent over time if the channel migrates ≤10% of the channel width over the feedback timescale. In contrast, channel trajectories diverge if the time step causes migration to exceed this threshold, due to the instability in the co‐evolution of channel curvature and migration rate. The divergence of channel trajectories accumulates with the total run time. Application to hindcasting of channel migration for 10 natural rivers from the continental US and the Amazon River basin shows that the sensitivity of modeled channel trajectories to the time step is greatest at low (near‐unity) channel sinuosity. A time step exceeding the criterion causes over‐prediction of the width of the channel belt developed over millennial timescales. These findings establish a geometric constraint for predicting channel migration in landscape evolution models for lowland alluvial rivers, upland channels coupled to hillslopes and submarine channels shaped by turbidity currents, over timescales from years to millennia.

Analysis of Friction Characteristics of Valve Plate Pair in an Axial Piston Pump Considering Cylinder Block Dynamics

Abstract The lubrication properties and friction characteristics of the valve plate pair play a vital role in determining the overall lifespan of the axial piston pump, which makes the analysis of these parameters of significant importance. In this paper, the lubrication model of the cylinder block/valve plate sliding interface of the axial piston pump, considering elastic deformation and cylinder block dynamics, is established. The oil film carrying pressure and asperity microcontact pressure are calculated using the Reynolds equation, Greenwood–Williamson asperity microcontact model, and Hertz contact theory. The dynamic analysis is carried out, and the Newton–Raphson iterative method is introduced to solve the nonlinear equations. The influence of working pressure, cylinder speed, and sealing belt width on the friction characteristics of the valve plate pair is analyzed using the numerical calculation model. The simulation results demonstrate the dynamic changes of the cylinder block and the impact of them on lubrication properties and friction characteristics. The experimental results of the friction coefficient at different cylinder speeds are consistent with the simulation results in trend and accurately reflect the fluctuation of the friction coefficient.

Optimal Layout of the Head Drive for a Self-Supporting Bucket Elevator of High Productivity

The article deals with bucket elevators of high productivity. The demand for grain crops is growing worldwide, requiring transportation, transshipment, and storage in huge volumes. Based on this, it is urgent to solve the problem of increasing the productivity of bucket elevators in the self-supporting version. The problem is that increasing performance requires increasing the drive’s power, leading to a significant weight increase. This imposes a limit on the height of the bucket elevator. A considerable weight at a high altitude significantly reduces the stability of the structure itself. For the most part, this problem was solved by limiting the height or productivity of the bucket elevator. The construction of a self-supporting bucket elevator, possible layouts of the head drive, and advantages and disadvantages were considered. Three bucket elevators with different heights, productivity, and belt width were selected to determine the optimal layout. Four drive options were calculated for each design, and a comparative analysis was carried out using a graphical method. The analysis showed that one of the biggest problems is the displacement of the center of mass relative to the central plane of the bucket elevator. As a result, means to ensure the smallest displacement coefficient relative to the vertical axis of the bucket elevator were presented. Advantages, disadvantages, and the possibility of constructive implementation of the layouts were also considered.

ОЦЕНКА ПАРАМЕТРОВ ПЛОСКОРЕМЕННОЙ ПЕРЕДАЧИ, РАССЧИТАННЫХ В МОДУЛЕ АРМ TRANS СИСТЕМЫ АРМ WINMACHINE, ПРИ ИЗМЕНЯЮЩИХСЯ КИНЕМАТИЧЕСКИХ УСЛОВИЯХ

An analysis was made of the flat-belt transmission parameters calculated in the APM Trans module of the APM WinMachine system. In the calculation methodology, traction capacity (reliability of adhesion of the belt to the pulley) and durability, determined by the fatigue strength of the belt, are taken as criteria for transmission performance. In accordance with this, the design calculation is made for traction capacity depending on the operating conditions of the transmission (with changing gear ratios), and the verification calculation is made for durability. Analysis of the calculation results shows that the geometric parameters of the flat belt transmission and the force dependencies for the calculated belt thicknesses did not change at the given gear ratios. In this case, the calculated belt thicknesses are the determining parameters in the recommendations for choosing the minimum diameters of the drive pulleys. To organize the operation of the transmission, it is necessary to ensure pre-tension of the belt, while the driving and driven branches will experience the same force. The results of calculating the power parameters of the transmission show that with an increase in the transmission ratio, the pre-tensioning force and the load on the shafts and supports decrease. After applying the transmitted working load, a redistribution of tension occurs in the belt branches: when the flexible element runs around the drive pulley, its tension decreases, and on the driven pulley it increases. The force parameters were calculated using recommendations taking into account the equilibrium of the pulleys and Euler's equations. Calculations have established that various physical approaches at a certain friction coefficient and sliding arc length give comparable results (relative error no more than 2.4%). A durability test based on the results of a computer calculation revealed that the maximum stresses of the belt endurance limit were exceeded (the strength of the flexible element depends on the thickness and width of the belt). It is shown that in order to meet the strength condition, it is necessary to make adjustments to the design calculation: take the belt width from a number of standard sizes in the direction of increasing values. Strength calculations based on adjusted geometric dimensions determined the areas of use of flat belt drives.

Shelf and Lower-Shoreface Deposits in the Upper Midway Group and the Transition into Fluvial-Dominated Deltaic Deposits in the Hooper Formation (Lower Wilcox Group) in the Southeastern Texas Gulf Coast

The Paleocene Upper Midway Group in the southeastern Texas Gulf Coast records a stratigraphic succession of shelf and lower-shoreface systems. Four (4) recognition criteria for these systems include (1) thin (&lt;2 ft [&lt;0.6 m]), erosion-based and lenticular, very fine-grained and fine-grained sandstone beds with swaley cross-stratification, (2) a diverse Cruziana trace-fossil assemblage consisting of Teichichnus, Palaeophycus, Planolites, and Schaubcylindrichnus, (3) net-sandstone trends consisting of strike-elongate ribbons and pods that merge updip (north and northwest) into broad, sheet-like patterns, and (4) an absence of northwestern and northern feeder systems inferred from net-sandstone maps. Net-sandstone trends in Upper Midway shelf deposits in southeastern Texas are irregular and narrow, strike-elongate pods and ribbons ranging in thickness from 20 to 35 ft (6 to 11 m). They grade southward and southeastward into extensive, muddy areas with &lt;10 ft (&lt;3 m) of net sandstone. In contrast, lower-shoreface deposits at the top of the Upper Midway Group contain wide (&gt;10 mi [&gt;16 km]) strike-elongate belts of &gt;40 ft (&gt;12 m) of net sandstone. These belts extend northeastward &gt;50 mi (&gt;80 km) along depositional strike. Sandstone-body continuity, inferred from wireline-log cross-sections, differs greatly among these shelf and lower-shoreface deposits. Sandstone-body continuity in Upper Midway lower-shoreface deposits at 10 mi (16 km) well spacing is approximately 60%, whereas it is only 20% at the same well spacing in shelf deposits. At 20 mi (32 km) well spacing, lower-shoreface sandstone-body continuity is 37% but only 4% in shelf deposits. Microscale heterogeneity in the Upper Midway Group is related to sedimentary structures and accessory features that disrupt vertical sandstone-bed continuity over scales of millimeters to centimeters. These include mudstone drapes, scour surfaces, shell debris, mudstone clasts, and trace fossils. Mesoscale heterogeneity, inferred from cores and wireline-log cross-sections, is defined by lateral sandstone-body pinchouts and vertical stacking patterns. In contrast, macroscale heterogeneities in the Upper Midway Group, inferred from net-sandstone maps, compose facies architecture at a regionally-mappable scale. They include paleogeographic elements such as shelf sand-shoal complexes, strike-fed shoreface systems, and abandoned-deltaic headlands. These paleogeographic elements extend for tens of miles or kilometers along depositional strike from southwest to northeast. The transition in depositional systems in the Upper Midway Group to the Lower Wilcox Group is abrupt, recording a change from wave-dominated shelf and shoreface systems to fluvial-dominated deltaic depositional systems. Dip-elongate, fluvial-dominated deltaic deposits at the base of the Wilcox Group (Hooper 1 depositional unit) have depositional axes oriented orthogonally with respect to those in the underlying Midway Group. Hooper 1 depositional axes are narrow (commonly &lt;4 mi [&lt;6.4 km] across. They are erosionally-based, net upward-fining, and composed of fine- to medium-grained sandstone with abundant siltstone and mudstone rip-up clasts. Distributary-channel trends in the Hooper 1 depositional unit are connected southward and southwestward to downdip-bifurcating trends representing upward-coarsening sub-delta deposits that pinch out into interdistributary mudstones. Microscale heterogeneity in fluvial-dominated deltaic deposits in the lower part of the Hooper Formation occurs at the scale of large (&gt;2 in [&gt;5.1 cm]) diameter siltstone and mudstone clasts in distributary-channel deposits. Mesoscale heterogeneity is controlled by lateral pinchouts of distributary-channel sandstone bodies into floodplain and interdistributary mudstones. Macroscale heterogeneity is represented by numerous dip-elongate distributary-channel depositional axes that segment lower-coastal-plain systems into discrete sandy depocenters. Six Hooper 1 deltaic depocenters occur along a 60 mi (96 km) span along the Angelina-Caldwell Flexure. Sandstone-body continuity along depositional strike (southwest to northeast) in the Hooper 1 depositional unit is poor, being only approximately 25% at 10 mi (16 km) well spacing. These sandstone-body continuity values record the presence of multiple, locally occurring deltaic depocenters within a fluvial-dominated deltaic system, in contrast to the wave-dominated shelf and lower-shoreface deposits in the underlying Upper Midway Group.