Channel Deformation Research Articles

МОРФОЛОГИЧЕСКИЙ АНАЛИЗ РУСЛА РЕКИ КОНДЫ

The article presents the results of long-term studies of the Konda River basin (Khanty-Mansi Autonomous Okrug). Despite the fact that the Konda is one of the largest rivers in the region, hydrological studies of the river are fragmentary and there are no studies on channel processes. The Konda plays an important role in the social and economic life of the southwestern part of Khanty-Mansi Autonomous Okrug–Yugra as it is one of the main transport routes for interdistrict communication. This article is the first to give a generalized description of manifestations of channel processes – types of channels, bends, conditions and regularities of their development – for the navigable section of the Upper, Middle and Lower Konda (from Lake Tursuntsky Tuman to the mouth). The author discusses the issues related to the development of channel deformations, describes a typical set of morphometric characteristics for different types of channels, classifies them, shows the possibilities of practical use of the research results for forecasting channel deformations. It has been revealed that in the Lower Konda, with a great variety of channel types, the most active deformations are characteristic of channel bends and bends of floodplain branching arms and a bifurcated channel; in the Upper and Middle Konda, having a mainly meandering channel, bank erosion is confined to free channel bends.

Calculation of Total Erosion in the Lower Reaches of Mezhdurechensk Reservoir Using Empirical Morphometric Dependencies

The research aims are to develop a methodology and the choice of initial formulas for calculating channel deformations in the lower reaches of waterworks on rivers composed of easily eroded soils (like the Amu Darya river). To calculate the total erosion below the Mezhdurechensk reservoir, both theoretical equations of channel deformation (Saint-Venant equations) and empirical dependences of the transporting capacity of the flow (turbidity) and morphometric dependences of the connection of the width of the deformable channel from the average depth obtained for the lower reaches of the Takhiatash hydrounit, the stem of which is located slightly above the Mezhdurechensk hydrounit, were used. A hydrological series of years was formulated for the calculation (considering the actual frequency of low-water, medium-water, and high-water years). The results of calculating the total erosion of the bottom in the first ten years of the simulated hydrological series of years, provided that the width of the channel in the lower reaches is constant, is expected to be 0.17-0.41 m (with full flow clarification) and 0.16-0.38 m (with partial flow clarification ε = 0.8). The change in the cross-sectional area of the riverbed will be 304(292)m2. Provided that the width narrows to a stable width Bstable =kha : Δz = 0.41 m (with the concentration of the flow at a narrower width, the decrease will be correspondingly large). The proposed methodology can be applied to calculate the total erosion on rivers composed of easily eroded soils and having average slopes of the longitudinal profile of the river within 0.0001 (similar to the Amu Darya River).

Hydraulic resistances of eroded riverbed and assessment of their sustainability

In the world, due to the shortage of water resources, the most important issues are the rational use of water resources, the assessment, and the improvement of the capacity of riverbeds and channels. In this regard, research developments on improving the methods of the hydraulic calculation of the resistance and the stability of mobile river channels and channels are of particular importance. The results of some theoretical and experimental studies of hydraulic resistances and the stability of watercourses by scientists in the CIS and abroad are considered. The analysis of massive field data on the Darcy coefficient (Shezi) of earth channels covered in a sandy mobile bed is performed. With a change in the flow velocity field, the roughness of the channel surface changes, changing its size and shape, which determines the channel's resistance to flow movement. It is established that in stable channels with certain widths, the flow velocity is evenly distributed, having one maximum along the channel axis, and the movement is carried out in the form of a compact single jet along the flow cross-section. With changes in hydraulic conditions, the curvature of the isotopes is observed, the flow tends to split, and several closed systems of rotating the jet appear, which are signs of the development of channel deformations.

Воздействие отработанных месторождений россыпной платины на речную систему р. Вывенки (Камчатский край)

Geological exploration and mining operations have been conducted in the Vyvenka River basin on the Seinav-Galmoenan platinum deposit since 1994. The majority of the explored and prospective reserves are located in the valleys of spawning salmon tributaries, raising concerns about the environmental impact of mining activities. Despite the cessation of platinum mining in the 2010s, there has been a continuing impact on the river system in recent years, with extensive sediment plumes forming along the length of the rivers. This research aims to assess the dynamics of disturbed lands and determine the scale of sediment export into the river network from the territory of the ore mining sites of Vetvisty, Penisty, Ledyanoy, Yuzhny, and Levtyrinivayam. Field and satellite data were combined to analyze the suspended sediment discharge regime and the main sediment sources, i.e., the riverbank deformations along the mining sites. As of 2021, the total area of disturbed lands in the Vyvenka basin due to open-cast platinum mining is estimated to be 19.2 km2 corresponding to 0.15 % of the area of the Vyvenka River basin. Up to 75 % of the disturbed area consists of bare lands, making them prone to surface erosion. The largest amounts of sediment influx from the mining-affected river basins were observed in 2018 during the unevenly high freshet. The increased sediment discharge was due to the overflow of sedimentation ponds in certain areas. The study results indicate a prolonged anthropogenic impact on river ecosystems, manifested in the change of hydrological regime, activation of channel deformations, and the increased sediment influx to the river network from ore mining sites.

Моделирование русловых процессов в створе канала

An erosion mathematical model of a sand channel coastal slope, which occurs under the influence of passing flood wave, is formulated. The model includes the equation of motion of a quasi-steady hydrodynamic flow in the channel section. The movement of the bottom and bank surface of the channel is determined from the solution of the Exner equation, which is closed by an original analytical model of the movement of traction sediments. The model takes into account transit, gravitational and pressure mechanisms of movement of bottom material, and does not contain phenomenological parameters. The movement of the free surface of a hydrodynamic flow is determined from the interpolation of experimental data. The model takes into account changes in the average turbulent viscosity along the alignment when the channel alignment changes. The influence of quasi-steady hydrodynamic flow on mass loss in the channel section was studied. A criterion has been introduced to determine the disequilibrium of the channel flow. It is shown that to model channel deformations in this case, it is necessary to take into account a non-zero gradient of sediment movement along the channel axis. Numerical calculations have been carried out demonstrating the qualitative and quantitative influence of these features on the process of determining the turbulent viscosity of the flow and the erosion of the coastal slope of the channel. Data comparison on coastal deformations obtained as a result of numerical calculations with known flume experimental data showed their good agreement.

ОЦІНКА ВЕРТИКАЛЬНИХ РУСЛОВИХ ДЕФОРМАЦІЙ РІЧОК БАСЕЙНУ ТЕТЕРЕВА

The investigation of vertical channel deformations of the main rivers of the Teteriv basin over the last 40 years according to the data of 6 hydrological stations was carried out. The prerequisite for this was the establishment of trends in changes in the water discharge of the considered watercourses. A general decrease of these indicators, especially the average and maximum flow indicators, was revealed. This is confirmed by previously conducted studies on water level fluctuations of the researched rivers. The results proved a universal increase in water levels for the rivers of the basin at fixed water discharge within the river banks. This is evidence that accumulation processes are observed on all explored riverbeds, although their intensity may be manifested in different ways. It is shown that modern vertical channel deformations characterize the accumulation of sediments in the riverbeds of the basin, the average intensity of which varies within 0.27-1.31 cm/year. In general, this trend is confirmed by the change in the longitudinal profiles of the rivers during the specified period, where in the areas where the hydrological stations are located, a slight shift of one relative to the other can be observed, with the prevailing height positions of the longitudinal profile for the year 2020. Comparative analysis of discrete (according to flow curves based on data from hydrological stations) and continuous (according to longitudinal profiles) estimates of vertical channel deformations makes it possible to more objectively establish the trends of their manifestations.

Methods of channel calculations to improve the operational mode of main canals

The article discusses solutions to improve the operational mode of the canal with an increase in throughput by means of self-washout, while maintaining the morphometric favorable stable cross-section of the canal for further reliable water supply of suspended crop areas. Taking into account the characteristics of the course of channel deformation processes, we have considered the modern dynamics of channel flows for accurate calculation of channel deformations using the systems of equations of one-dimensional flow in the deformable Saint-Venant channel or two-dimensional shallow water equations (planned task), which will give a positive result for the operational mode of the main canals.

СУЧАСНІ УМОВИ ФОРМУВАННЯ СТІЙКОСТІ РУСЕЛ РІЧОК РАЙОНУ РІЧКОВОГО БАСЕЙНУ ДНІПРА (В МЕЖАХ УКРАЇНИ)

Assessment of the stability of riverbeds is one of the most important components in the analysis of riverbed processes and is of great practical importance. At the same time, it includes an ecological content, which is primarily related to the analysis and forecast of the intensity of channel deformations, which can significantly affect the conditions of life and management within the river channel-flood complex. The concept of stability of riverbeds consists in their comparison based on the quantitative assessment of conditions and the rate of manifestation of channel deformations. The study of channel processes in rivers and the conditions that shape their stability is closely related to the mechanism of water erosion in their basins. Therefore, for a more objective assessment of channel processes in general and the stability of river channels in particular, it is necessary to take into account all water-erosion processes in the river basin. Research and classification of various approaches to assessing the stability of riverbeds has been carried out. An additional substantiation of the erosion resistance indicator Lo was confirmed and conducted. A retrospective analysis of its spatio-temporal changes in the erosion coefficient and erosion resistance index was carried out based on the data of 17 representative hydrological stations located on the rivers of the Dnieper basin (within Ukraine). The research results confirmed the low variability of the Lo indicator during the last 30 years with the presence of a tendency to increase the stability of riverbeds according to this indicator. A comparative analysis with other indicators of stability shows the best coincidence of the erosion indicator of channel stability Lo and the indicator of relative invariance Mx, which can be recommended for further use in the study of channel formation processes of the indicated rivers.

Assessment of problematic sections of raft transportation on the Verhnyaya Kama river from Bondyug village to Solikamsk caused by riverine deformations and ways to eliminate them

The analysis of channel deformations of the limiting sections of rivers is the basis for choosing a scheme for radically improving navigable conditions on them. On the example of the Verhnyaya Kama on the section from Bondyug village to Solikamsk, studies of longitudinal and planned long-term deformations causing difficulties for navigation were carried out. The characteristics of the sections difficult for navigation from the village of Bondyug to Solikamsk are given.The main trends in the development of the channel along the sections within the boundaries under consideration and the intensity of channel deformations are determined. The nature of long-term deformations is very diverse. The entire area is divided into short periods of sediment accumulation and longer periods of erosion. On the basis of the performed analysis of long-term channel deformations, a set of track works was proposed, including dredging and erection of corrective structures that contribute to the elimination of problematic water nodes.

Investigation of the current state of the tailwater of the Nizhny Novgorod hydroelectric power station, taking into account channel deformations and the effect of dredging

Integrated waterworks on rivers have a great impact on the state of natural waterways. With the commissioning of hydroelectric facilities and reservoirs that regulate river flow, a new hydrological and channel regime is created; the intensity and nature of channel processes change. The regulation of the runoff by hydropower systems introduces changes in the travel and navigation conditions of the river in question, especially in the lower pools. In this paper, an assessment is made of the current state of the lower pool of the Nizhny Novgorod hydroelectric power station, which is one of the areas limiting navigation throughout the entire unified deep-water system of the Russian Federation. The results of studies of the effect of dredging on the level regime of the tailwater are also presented.

Morphological response of the upper Yangtze Estuary to changes in natural and anthropogenic factors

AbstractGlobally, over the past few decades, extreme river channel deformation has been observed downstream of dams. Specially, estuarine channel deformation and its response to natural and anthropogenic factors are key issues influencing channel regulation and prediction of long‐term stability in large estuarine deltas. Herein, bathymetry data for the upper reaches of the Yangtze Estuary (YE), China was collected for the years 1995, 2003, 2008, 2013, and 2019 to analyze the channel deformation process. Our findings show that the total erosion volume was approximately 11.22 × 108 m3, an equivalent of 15.7 × 108 t of sediment assuming a bulk density of 1.4 t/m3 for the riverbed material during 1995–2019. Meanwhile, the annual erosion rate is 0.63 Mt/year in 1995–2019, and the annual erosion rate is 0.90, 0.12, 0.40 Mt/year in 1995–2003, 2008–2013 and 2013–2019, respectively. Meanwhile, the annual deposition rate is 0.7 Mt/year during 2003–2008. Further analysis indicated that continuous reduction of the sediment load due to the construction of dams (e.g., the Three Gorges Dam) in the basin was a key factor influencing channel erosion over the past 24 years. The channel deformation process was characterized by severe erosion during 1995–2003, a deposition period during 2003–2008, a dynamic equilibrium period from 2008–2013, and an erosion period after 2013. Due to floods with maximum peak discharge lower than 70,000 m3/s, despite the annual sediment load is reduced, the channel deposition phenomenon occurred in 2003–2008. The channel changed from a depositional system to an erosion system during 2008–2013. After 2013, the channel was dominated by extensive erosion, severe local deposition, or severe local erosion as a response to anthropogenic interventions. These findings are of great significance to river management and regulation, as well as to the navigational safety.

Численное моделирование самосогласованной динамики поверхностных вод, влекомых и взвешенных наносов: II. Исследование поперечных деформаций русла и перераспределения расходов воды по рукавам р. Волги при промышленной добыче песка

The dynamics of water levels, transverse channel deformations, and redistribution of water discharges along the branches of the Volga River, both during planned industrial sand mining and during extreme transformation of the bottom topography in the area of the quarry, have been studied. A real quarry of non-metallic building materials was considered, located at the mouth of the Volozhka Partridge of the Volga — Akhtuba floodplain (VAF) in the section 2549–2550 km of the Volga River. Mathematical modeling of the joint dynamics of shallow waters, traction and suspended sediments is carried out, which takes into account the nonlinear dynamics of the liquid and bottom deformations. For the numerical solution of the Saint-Venant and Exner equations, the CSPH-TVD method was used, the parallel CUDA algorithm of which is adapted for highperformance computing on supercomputers with graphics coprocessors (GPUs). It is shown that the conditions of quarry development, both during planned mining and under extreme bottom deformation, do not significantly affect the structure of channel flows along shipping routes.

An improved springback model considering the transverse stress in microforming

To satisfy the higher accuracy requirement in the microforming of thin-walled structures, the springback behavior under miniaturizing dimensions need to be accurately predicted and controlled. However, as the feature size approaches the thickness in microforming, many assumptions in conventional springback model for macroforming are not valid making these models can hardly provide effective springback analysis in microforming. In the present work, the applicability of a springback analytical framework of conventional stretch-bending was first explored via bending tests of 0.1 mm-thick SS316L sheets under different holding conditions with a punch radius from 3 to 5 mm which is much greater than the thickness. The analytical springback angle results agree with the experimental ones with the maximum error of 4.2% for different punch radii, grain sizes and stretching forces conditions, indicating the correctness of the model. The model was further verified in the microforming of parallel channels with a fillet radius of 0.15 mm. Finite element simulations were conducted to obtain the stretching loads for each channel. However, a significant underestimation of the channel height after springback for over 15% was found especially for the middle channel. The transverse stress is revealed to be no longer neglectable due to the strong stretching load and the small die radius during the microforming of parallel channels, which substantially contributes to yielding, hardening and thickness reduction in the stretch-bending area. In addition, the uneven stretching also affects the springback angle and channel height, which is caused by the nonuniform plastic deformation of the adjacent channels. By incorporating the effects of the transverse stress and the non-uniform stretching loads, an improved springback model was developed for microforming of parallel channels in this work. The shift distance of the neutral plane is better estimated by the improved model than by the conventional one. The predictive heights by the improved model are also revealed to agree with the experimental ones during the microforming of parallel channels with a maximum error of less than 5%.

Substantiation of conditions for the creation and use of navigable depths on the Upper Kama in the expedition period of navigation

The conditions for the creation and use of navigable depths on the Upper Kama were determined by studying the level regime in the section from Bondyug village to the Tyulkino urban settlement. On this section which is 97 km long, raft transportation is carried out only in the short-term full-flowing spring period, which limits the possibility of using water transport. In order to extend the period of withdrawal of rafts on the site and establish guaranteed dimensions of the ship's course, the proposed methodology substantiates the marks of the design levels for the reference hydraulic posts and evaluates the possibility of establishing guaranteed depths. The defining conditions for creating depths are the developed complex of track works and the hydraulic capabilities of the river, taking into account the peculiarities of channel deformations on the site. Recommendations on the organization of raft transportation depending on the depths in the extended expedition period are given.

Slope Deformation Prediction Based on MT-InSAR and Fbprophet for Deep Excavation Section of South–North Water Transfer Project

In the operation and maintenance of the South–North Water Transfer Project, monitoring and predicting the canal slope deformation quickly and efficiently is one of the urgent problems to be solved. To predict the slope deformation of the deep excavated canal section at the head of the canal. We propose a new idea of adopting the joint prediction of MT-InSAR and Fbprophet. Firstly, MT-InSAR monitoring technology was used to invert channel deformation using 88 Sentinel-1A orbit-raising image data with a time baseline from 2017 to 2019. The time-series deformation of nine monitoring points was also extracted, and it was found that the time-series curves of the cumulative deformation of the channel slope showed fluctuations. The Fbprophet algorithm was then used to train the prediction model in Python to predict the channel slope deformation over the next 365 days. Finally, the prediction results were compared with the MT-InSAR monitoring values to analyze the prediction accuracy and applicability of the Fbprophet algorithm for the slope deformation monitoring of the South–North Water Transfer Project. The results show that: the deformation rate of the slope of the deep excavation section is in the range of 10 mm/a to 25 mm/a, the maximum accumulated deformation is about 60 mm, and the slope of the excavation canal shows a lifting phenomenon; among the nine monitoring points, the minimum and maximum predicted values of deformation using the machine learning prediction model trained in this paper were 56 mm and 73 mm, respectively; comparing the predicted and monitored values, their correlation coefficients were 0.998 at the highest and 0.988 at the lowest, and the minimum and maximum values of RMSE (RootMean Square Error) were 0.72 mm and 2.87 mm, respectively. It shows that the prediction model trained by the Fbprophet algorithm in this paper applies to the prediction of slope deformation in the deep excavation section, and our prediction results can provide a data reference for disaster prevention and the sustainable development of the South–North Water Transfer Project.

Investigations on the intrinsic and template-dependent transformations of AlPO4-11 molecular sieve under high pressure

In this study, aluminophosphate molecular sieve AlPO4-11, with one-dimensional elliptical channels, was investigated under high pressure in non-penetrating silicone oil by X-ray powder diffraction, infrared spectroscopy and theoretical simulation, focusing on its intrinsic and template-modified mechanical behaviors. Two distinct compressible regimes were observed for both the calcined and as-synthesized AlPO4-11 frameworks before pressure-induced amorphization (PIA). The channel cross-section in the calcined AlPO4-11 framework showed an obvious increase in the ellipticity during this process. The framework structure began to lose crystallinity at approximately 2–3 GPa and underwent significant amorphization at 6.6 GPa. PIA was mainly induced via the destruction of the constructed species along the periodic crystallographic planes which are parallel to the channel axis. The bulk moduli showed that this empty framework was rather soft in these regimes. For the as-synthesized AlPO4-11 framework, the mechanical stability of the channels was markedly improved by the template molecules. A different elliptic deformation of the cross-section with a reduced contractility in the minor axis direction was presented. Discontinuous volume evolution occurs at 3–4 GPa and significant amorphization was postponed to 13.7 GPa. The as-synthesized AlPO4-11 was stiffer than calcined AlPO4-11 and showed a soft to hard transformation due to the strengthened host-guest interaction upon compression. Moreover, infrared spectra indirectly confirmed the structural collapses by detecting the vibrational characteristics of the embedded template molecules. The present results provided a comparative and basic knowledge of the intrinsic and extrinsic stability, compressibility, channel deformation and collapse of the AlPO4-11 framework under high pressure. This study emphasized the importance of guest molecules in modifying the mechanical behaviors of zeolites and resisting framework collapse.

Design of Flexible Pressure Sensor Applied to Mechanical Gripper

Flexible electronic devices have emerged as a novel and popular research direction in the field of artificial intelligence, in which flexible sensor is an indispensable branch of flexible devices. In this article, a flexible pressure sensor is developed based on a liquid metal microchannel, which has the advantages of convenient measurement and easy integration. The sensor adopts Dragon skin 20 as the sensor matrix and Ga-In-Sn alloy as the conductive liquid. Meanwhile, there are two kinds of sensor structures are introduced which are the sensor only has a sensing layer and the sensor with an amplification layer. Through comparison of mechanical simulation models, the results suggest that adding the amplification layer structure can make the channel deformation more obvious, and the resistance change will be larger under the identical pressure, which indicating that adding amplification layer can effectively improve the sensitivity of sensor. We further demonstrate the basic characteristics of the sensor, and finally, it is proved by experiments that it can be installed on the mechanical gripper used to sense the pressure. This indicates that the flexible pressure sensor has relatively high sensitivity and the resistance value of sensor can well change with the size of pressure, which also indicates that the flexible pressure sensor has the possibility of applying in orchard manipulator picking for grasping force sensing to prevent peel breakage.

Reinforced Metal Bipolar Plate Structure with Stiffening Rib Channel for Proton Exchange Membrane Fuel Cell

Clean energy has become a concern because fossil fuels are the primary cause of climate change and air pollution. A proton exchange membrane fuel cell (PEMFC) is an environmentally friendly vehicle's alternative energy source. Bipolar plates, gaskets, gas diffusion layers, and a membrane electrode assembly (MEA) constitute a PEMFC. The bipolar plate accounts for a large portion of the fuel cell stack cost. Metallic bipolar plates are utilized in vehicle fuel cell stacks because of its low fabrication cost, high manufacturability, mechanical strength, and low weight. Despite the benefits, a thin metal plate's major drawbacks are deformation and corrosion resistance.Stamping metallic plates form trapezoidal cross-section channels, whereas machined graphite bipolar plates can form rectangular cross-section channels. These trapezoidal channels make dimensional errors such as draft angle and fillet radius. Besides, the spring back effect makes shape errors in the manufacturing process. Many kinds of research are conducted to understand the impact of channel tolerances on the performance of PEMFCs. Mainly, inhomogeneous compression in the gas diffusion layer results from channel deformation caused by unevenly distributed clamping force and shape inaccuracy of the metal bipolar plates. High contact resistance and non-uniform reactant gas distribution would result from inhomogeneous compression of GDL.A reinforced metal bipolar plate structure with a stiffening rib channel is proposed in this work to reduce bipolar plate deformation and improve gas transfer. Stiffening ribs are imprinted on the top of the channel. The geometric parameters of the stiffening ribs are shown in Fig. 1. Four geometric design parameters are selected in this study, the distance between the ribs d1, length of the rib l1, height of the rib l2, width of the rib l3. The stainless steel with a thickness of 0.1mm, 50mm×50mm active area, is used. The influence of stiffening ribs on mechanical and fluid characteristics is investigated through numerical analyses and experiments. The static structural analysis illustrated the deformation of the bipolar plates and GDL under the clamping force. The stiffening rib design improves the structure's mechanical strength, lowering bipolar plate deformation. When the endplates clamp the stack, the stiffening rib supports more stress to prevent deformation. The flow distribution in the flow field channel and GDL was then visualized using computational fluid analysis. Stiffening ribs increase the velocity of the reactant. Enhanced under rib convection makes reactant gas evenly distributed. In addition, stiffening ribs causes a convective flow beneath the rib, which improves PEMFC performance. Finally, single-cell studies proved that the modeling results are valid. Under the same operating conditions with the same geometry to the model, electrochemical reactions are investigated to decouple the leading cause of the resistances. The ohmic resistance decreases with the robust structural stiffening ribs, and the mass transport resistance decreases with the well-distributed reactants flow. Figure 1

Improving the 3D Printability of Sugar Glass to Engineer Sacrificial Vascular Templates.

A prominent obstacle in scaling up tissue engineering technologies for human applications is engineering an adequate supply of oxygen and nutrients throughout artificial tissues. Sugar glass has emerged as a promising 3D-printable, sacrificial material that can be used to embed perfusable networks within cell-laden matrices to improve mass transfer. To characterize and optimize a previously published sugar ink, we investigated the effects of sucrose, glucose, and dextran concentration on the glass transition temperature (Tg), printability, and stability of 3D-printed sugar glass constructs. We identified a sucrose ink formulation with a significantly higher Tg (40.0 ± 0.9°C) than the original formulation (sucrose-glucose blend, Tg = 26.2 ± 0.4°C), which demonstrated a pronounced improvement in printability, resistance to bending, and final print stability, all without changing dissolution kinetics and decomposition temperature. This formulation allowed printing of 10-cm-long horizontal cantilever filaments, which can enable the printing of complex vascular segments along the x-, y-, and z-axes without the need for supporting structures. Vascular templates with a single inlet and outlet branching into nine channels were 3D printed using the improved formulation and subsequently used to generate perfusable alginate constructs. The printed lattice showed high fidelity with respect to the input geometry, although with some channel deformation after alginate casting and gelation-likely due to alginate swelling. Compared with avascular controls, no significant acute cytotoxicity was noted when casting pancreatic beta cell-laden alginate constructs around improved ink filaments, whereas a significant decrease in cell viability was observed with the original ink. The improved formulation lends more flexibility to sugar glass 3D printing by facilitating the fabrication of larger, more complex, and more stable sacrificial networks. Rigorous characterization and optimization methods for improving sacrificial inks may facilitate the fabrication of functional cellular constructs for tissue engineering, cellular biology, and other biomedical applications.

Similar simulation test study on the influence of mining on shaft deflection of deep soil based on hydraulic permeability model

Ensuring shaft safety is critical in the process of coal mining. During coal mining in the Guotun coal mine, Shandong Province, China, issues, such as shaft deflection, tank channel and shaft deformation, and tank jamming, which did not appear in the shaft before, brought huge hidden dangers to safety. In this study, a set of three-dimensional analog simulation systems for assessing the influence of mining on shaft deflection was designed by using penetration force simulations of gravity fields. In this system, electromagnetic displacement meter is used to collect surface settlement data, which verifies the feasibility of using hydraulic pillow to simulate formation disturbance caused by coal mining. the strain of the shaft is measured by optical fibers and strain gauges, and the amount that mining influenced the deflection of the shaft is obtained. The results show that there is an approximately positive linear correlation between the horizontal displacement of the shaft caused by mining and the mining thickness of the coal. The horizontal displacement of shaft caused by coal mining is inversely proportional to the moving Angle within a reasonable range. The horizontal displacement of shaft is affected by mining mode, and symmetrical mining can significantly reduce the horizontal displacement of shaft. The horizontal displacement of the shaft at different depths caused by mining decreases with increasing shaft depth, which is the main cause of shaft deflection.