Hasil untuk "Hydraulic engineering"

Ko Yamamoto, Kyosuke Ishibashi, Hiroki Ishikawa et al.

This paper presents a design methodology of a hydraulically-driven soft robotic gripper for grasping a large and heavy object -- approximately 10 - 20 kg with 20 - 30 cm diameter. Most existing soft grippers are pneumatically actuated with several hundred kPa pressure, and cannot generate output force sufficient for such a large and heavy object. Instead of pneumatic actuation, hydraulic actuation has a potential to generate much larger power by several MPa pressure. In this study, we develop a hydraulically-driven soft gripper, in which its basic design parameters are determined based on a mathematical model that represents the relationship among the driving pressure, bending angle, object mass and grasping force. Moreover, we selected materials suitable for grasping a heavier object, based on the finite element analysis result of the detailed design. We report experimental results on a 20 kg object grasping and closed-loop control of the finger bending angle.

Jonathan D. Paul, Aneena Ajmi, Doris Bolaji‐Dada et al.

ABSTRACT Groundwater behavior in superficial gravel aquifers is globally poorly understood, especially across urban regions where drinking water is sourced from elsewhere. This study focuses on one such region around Staines, SE UK, where local River Terrace Gravels form a thin (< 10 m) superficial aquifer. The objective was to explain the unusually broad and long‐lived distribution of flooding by investigating local groundwater level fluctuations and flow. Over a period in January 2024, a targeted citizen science program was instigated to leverage local knowledge of floodwater, which was determined to match groundwater chemistry. Geophysical surveys (ground‐penetrating radar and seismic refraction) were designed to produce high‐resolution water table maps, validated against well measurements. Flow rates and hydraulic conductivity, K, of the gravels were determined both in the field (via pumping and tracer tests) and laboratory, to obviate any scale effects. K depended nonlinearly on hydraulic gradient, with Darcyan behavior breaking down at low (< 0.03) gradients, in conditions approaching turbulent flow. Large and localized fluctuations in groundwater level, combined with the existence of several fast‐flow pathways, are explained by the strong heterogeneity of the gravels, as well as their sensitivity to the imposition of subsurface obstacles such as clay‐lined backfilled gravel pits, or deep basements. These manifestations of urbanization drive observed patterns of groundwater emergence, together with aquifer thickness, rather than changes in river stage or surface elevation alone. Our experience motivates us to suggest that groundwater flooding be considered as significant as fluvial flooding in the production of risk maps by environmental regulatory bodies.

Abebe Birara Dessie, Taye Melese Mekie, Tadie Mirie Abate et al.

Daniela Córdova de Horta, Bryan Pérez León, Luis Fermín Córdova López

Este trabajo tiene como objetivo la simulación dinámica de las inundaciones pluviales causadas por eventos meteorológicos extremos, centrándose en el drenaje dual en zonas costeras mediante modelación numérica. Se analiza el Malecón Tradicional de La Habana a través de tres escenarios diferentes. En el primero, solo se considera el escurrimiento superficial provocado por la inundación pluvial. En el segundo, además del escurrimiento superficial, se incorpora el volumen de agua captado por los sumideros. Finalmente, en el tercer escenario se incluye también el funcionamiento de la red de drenaje pluvial. La comparación de estos escenarios permite evaluar la eficiencia del sistema de drenaje y su capacidad para mitigar inundaciones, proporcionando información clave para la planificación y gestión del drenaje urbano en entornos costeros vulnerables.

Rashina Hoda

Agentic AI is poised to usher in a seismic paradigm shift in Software Engineering (SE). As technologists rush head-along to make agentic AI a reality, SE researchers are driven to establish agentic SE as a research area. While early visions of agentic SE are primarily focused on code-related activities, early empirical evidence calls for a consideration of a wider range of socio-technical activities and concerns to make it work in practice. This paper contributes to the emerging visions by: (a) recommending an expansion of its scope beyond code, toward a 'whole of process' vision, grounding it in SE foundations and evolution and emerging agentic SE frameworks, (b) proposing a preliminary set of values and principles to guide community efforts, and (c) sharing guidance on designing and using well-defined vocabulary for agentic SE. It is hoped that these ideas will encourage collaborations and steer the SE community toward laying strong foundations of agentic SE so it is not limited to enabling coding acceleration but becomes the next process-level paradigm shift.

JIN Gaoyang, ZHU Sanhua, CAO Yihao

To study the changes in the riverbed of the Northwest River Delta and their relationship with saltwater intrusion,this paper builds a one-dimensional unsteady flow chlorine concentration mathematical model based on the collection and organization of previous research results,hydrological,meteorological,and river terrain data.The hydrodynamic and chlorine concentration verification results meet the relevant regulatory requirements and can be applied to calculate and analyze the impact of riverbed changes on saltwater intrusion.The research results are as follows.① From 1999 to 2016, the riverbed of the Northwest River Delta network was in an uneven downward cutting state,and the volume of the river continued to increase,resulting in a decrease in the resistance of the estuary to rising and falling tides.The upward tracing of high saltwater masses along the estuary was simpler,and the upward tracing of salt tides became increasingly severe.② The rising tide at each Koumen station increases,and the probability of removing freshwater from the saltwater boundary decreases.Under different inflow conditions in Sixianjiao,the average upward movement of the saltwater boundary at Modaomen Waterway is 3 735 m,and the average downward movement of the freshwater from Pinggang Pumping Station is 5.33%.The average upward movement of the saltwater boundary at Shawan Waterway is 2 369 m,and the average downward movement of the freshwater from Shawan No.1 Water Plant is 5.14%.These seriously affect the ecosystem and normal water intake demand in the estuarine area.The research results can provide basic support for the research and engineering design of water supply safety measures in the Northwest River Delta and estuarine areas.

Jun Wu, Jingke Zeng, Hao Tang et al.

Navigable tunnels serve as an effective method to connect upstream and downstream navigation structures in mountainous regions with sharp bends. The towing resistance of ships in navigable tunnels, a key technical indicator for towing equipment development, demands focused research. Utilizing the innovative top towing method for tunnels, this study develops a physical model for towed navigable tunnels, conducts ship model tests, and measures and calculates the total resistance of ships towing through navigation under various conditions. Through resistance test results, it analyzes factors influencing the total resistance of ship navigation. The findings reveal: (1) regarding towing speed, at speeds exceeding 1.5 m/s, resistance spikes by 100 kN to 560 kN; (2) concerning water depth, at depths lower than 5.5 m, the impact on a ship navigation’s total resistance is pronounced, reaching 5 to 13 times that of calm water; (3) in terms of flow velocity, at velocities over 2 m/s, the impact on a ship navigation’s total resistance is substantial, amounting to 1.5 to 2 times the resistance at a flow velocity of 1.5 m/s; (4) in comparative analyses, the total resistance of ships towing through navigation in narrow tunnels is significantly higher than calculations based on existing formulas, increasing by 7 to 138 times.

PENG Zicheng, YANG Xiaohu, YANG Haichang et al.

【Objective】 Evaluating evapotranspiration and soil salinization is critical for soil and water management but challenging on large scales. This paper investigates the feasibility of using remote sensing technologies and meteorological data to estimate evapotranspiration and soil salinization in irrigated areas. 【Method】 The study was conducted in the Manasi River Basin in Northeastern China. It was based on the Surface Energy Balance System (SEBS) model, using the Landsat-8 remote sensing data and field sampling to estimate spatial distribution of both evapotranspiration and soil salinity in the studied area. 【Result】 ① The normalized vegetation index (R2 = 0.644 8), surface specific emissivity (R2 = 0.637 7), and surface temperature (R2 = 0.558 3) all showed a strong correlation with soil salinity, while surface albedo (R2 = 0.198 6) had a weaker correlation with soil salinity. ② Daily evapotranspiration (ET) in the Manasi River Basin ranged from 0.024 to 5.403 mm, with an average of 3.866 mm. ET decreased from the Southern irrigation area to the Northern Gobi region. ③ ET values less than 3.60 mm/d were associated with non-saline and moderate saline soils. For areas with ET between 3.60 mm/d and 4.05 mm/d, moderate soil salinity dominated. For areas with ET exceeding 4.05 mm/d, the proportion of severe soil salinity increased significantly. 【Conclusion】 Using remotely sensed satellite imagery, the SEBS model provides an accurate, high-resolution estimate of evapotranspiration in terrestrial systems. The evapotranspiration was positively correlated with soil salinity in the Manasi River Basin. These results can help improve land and water management in the region.

Ricardo Villalba-Briones, Paola Calle, Marynes Montiel et al.

Hydrogeochemical and microbiological parameters of groundwater samples in the Paipayales agricultural community in western Ecuador were studied to evaluate groundwater origin, contamination, and suitability for domestic use and irrigation. The water wells studied are typically shared by multiple families which account for 37% of the total community population. A total of 31 parameters of water samples from the wells used by the community were analysed by four laboratories at the ESPOL University. The parameters analysed included microbiological and chemical compounds, along with physical characteristics typically influencing water quality. As regards the World Health Organization (WHO), U.S. Environmental Protection Agency (EPA), and Ecuadorian standards, all samples failed to meet the required concentrations for at least one compound. The chemical analysis showed eight elements (cadmium, aluminium, ammonia, iron, manganese, chloride, and bromide) exceeded the maximum limits for drinking water in at least one well. Seventy percent of sampled wells failed to meet the maximum permissible limits for at least one chemical parameter. Water in all wells showed the presence of microbiological contaminants. The high natural groundwater salinity limits the ability to use this groundwater for irrigation purposes. Water in open and closed wells shows different hydrochemical and microbiological patterns. The presence of domestic animals and the lack of protection for wells may influence the quality of water. It is highly recommended that the authorities increase water supply and storage capacity to improve the availability of drinkable water in rural communities in the area.

Masod Sadipour, Mohammad Masoud Momeni, Majid Soltani

In this study, a computational simulation is employed to place two essential parameters, the permeability of vessels and hydraulic conductivity, under assessment. These parameters impact the movement of drug particles through vessels, and normal and tumoral tissue to examine the concentration of nanoparticles, interstitial pressure, and velocity. To provide a geometric model detailing the capillary network under normal and tumoral tissue conditions, the geometry is extracted via real image processing. Subsequently, the real conditions were considered to solve the equations pertaining to drug transport and intravascular and interstitial flows in the tissue. The results showed that an increase in permeability and hydraulic conductivity leads to an increase in drug concentration in the tumor. Finally, Methotrexate drug has the most effect in the treatment of tumors. Overall, the computational model for anti-cancer delivery provides a powerful tool for understanding and optimizing drug delivery strategies for the treatment of cancer.

Ertugrul Basar

Noise: an enemy to be dealt with and a major factor limiting communication system performance. However, what if there is gold in that garbage? In conventional engineering, our focus is primarily on eliminating, suppressing, combating, or even ignoring noise and its detrimental impacts. Conversely, could we exploit it similarly to biology, which utilizes noise-alike carrier signals to convey information? In this context, the utilization of noise, or noise-alike signals in general, has been put forward as a means to realize unconditionally secure communication systems in the future. In this tutorial article, we begin by tracing the origins of thermal noise-based communication and highlighting one of its significant applications for ensuring unconditionally secure networks: the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange scheme. We then delve into the inherent challenges tied to secure communication and discuss the imperative need for physics-based key distribution schemes in pursuit of unconditional security. Concurrently, we provide a concise overview of quantum key distribution (QKD) schemes and draw comparisons with their KLJN-based counterparts. Finally, extending beyond wired communication loops, we explore the transmission of noise signals over-the-air and evaluate their potential for stealth and secure wireless communication systems.

Jiuzhou Han, Wray Buntine, Ehsan Shareghi

Semi-structured explanation depicts the implicit process of a reasoner with an explicit representation. This explanation highlights how available information in a specific query is utilised and supplemented with information a reasoner produces from its internal weights towards generating an answer. Despite the recent improvements in generative capabilities of language models, producing structured explanations to verify a model's true reasoning capabilities remains a challenge. This issue is particularly pronounced for not-so-large LMs (e.g., FLAN-T5-XXL). In this work, we first underscore the limitations of supervised fine-tuning (SFT) in tackling this challenge, and then introduce a carefully crafted reward engineering method in reinforcement learning (RL) to better address this problem. We investigate multiple reward aggregation methods and provide a detailed discussion which sheds light on the promising potential of RL for future research. Our proposed method on two semi-structured explanation generation benchmarks (ExplaGraph and COPA-SSE) achieves new state-of-the-art results.

Matthew Tyler, Hengyun Zhou, Leigh S. Martin et al.

We introduce a framework for designing Hamiltonian engineering pulse sequences that systematically accounts for the effects of higher-order contributions to the Floquet-Magnus expansion. Our techniques result in simple, intuitive decoupling rules, despite the higher-order contributions naively involving complicated, non-local-in-time commutators. We illustrate how these rules can be used to efficiently design improved Hamiltonian engineering pulse sequences for a wide variety of tasks, such as dynamical decoupling, quantum sensing, and quantum simulation.

Yu Zhang, Dingli Zhang, Qian Fang et al.

Abstract Fluid flow in porous media is very important in a wide range of hydraulic and geotechnical engineering fields. The theoretical basis of fluid flow in porous media is based on the Darcy’s law. There are evidences that the fluid flow in porous media does not follow the Darcy’s law at very low velocity. The Darcy’s law is inappropriate for the low-permeability grouting zone of a subsea tunnel. Therefore, in this paper, we propose the impact of nonlinearity of low velocity flows on the drainage design of grouted subsea tunnels. The analytical solutions are derived by complex variable functions based on Hansbo's non-Darcy seepage model. The advantages of considering non-Darcy effects in the design of tunnel drainage system have been proved by both field monitoring and experimental data. The applicable conditions of our analytical solutions in subsea tunnel design and constructions are given. The analytical solutions are verified by numerical simulations and analytical analyses. The influences of non-Darcy parameters on the total hydraulic head and water inflow of grouted subsea tunnels are discussed. The design parameters of the grouted subsea tunnels, such as the ratio of permeability coefficients kr/kg and the grouted zone thickness hc, are investigated considering non-Darcy seepage. The results show that the non-linear seepage parameters have great influences on water inflow and water pressure of subsea tunnels. Our proposed methods can provide references for the drainage design in subsea tunnel projects.

F. Zhu, Lan Ding, Bin Huang et al.

Abstract Tidal turbine is a device which converts the kinetic energy of water into electric energy. The blade element momentum theory (BEM) is used to design the blade in this paper. Although tidal power resources are abundant, the actual operation of hydraulic turbines is not very good due to the limitations of turbine conversion efficiency and production cost. Therefore, this paper establishes a neural network model for variables and objective functions, and then applies multi-objective optimization algorithm to genetic optimization of the power coefficient, the main index of hydraulic performance of tidal turbines. The optimized results are verified by model test and sea trial. The results show that after optimizing the blade chord length distribution and pitch Angle distribution, the power coefficient of the turbine increases by 2%, and the optimal tip speed ratio range is also expanded, which is more conducive to the actual tidal turbine power generation, and has certain engineering significance.

Sambit Prasanajit Naik, Nihar Ranjan Patra, Javed N. Malik

Abstract The A.D. 1803 and 1934 Bihar-Nepal border earthquake affected Indo-Gangetic Plain with evidences of liquefaction in cities like Patna, Varanasi, Agra, and Delhi in historical past. Recent strong shaking all along the Indo-Gangetic Plains and seismic induced damage to the buildings in Bihar during Mw 7.8 Gorkha earthquake raises the concern for site specific liquefaction potential estimation of alluvial soils. Cyclic triaxial tests were conducted on soil samples from Kanpur, Allahabad, Patna city to know the cyclic behavior, estimate the dynamic soil properties and the effect of relative density, confining pressure and frequency of loading on the cyclic behavior of the soil tested. The test results indicate the cyclic strength of Allahabad soil is less than Patna and Kanpur soil. The Allahabad soil with 80% sand, 10% silt and clay each is more prone to liquefaction than Kanpur soil (82% silt, 16% clay and 2% sand) and Patna soil (10% Kankar, 95% sand, 5% silt). This study indicates soils having sand with silt percentage are more liquefiable than clean sand or silty soil. It can be concluded that the soil of Allahabad and Patna city is more prone to liquefaction than Kanpur soil.

Can Yang, Zhibin Hao, Huaqi Yuan et al.

A Circulating Water Channel (CWC) is an important piece of equipment for hydrodynamic tests in ocean engineering, the quality of the flow field produced by the CWC directly affects the accuracy of the experimental results. Optimizing the key parts of the CWC device can efficiently improve the velocity uniformity and helps to achieve a high-level flow performance. In this paper, a CWC flume is set up numerically, and a series of hydrodynamic tests were carried out to evaluate the flow uniformity by optimizing the turning vane and contraction section. The numerical model is solved based on the RANS equation by using the RNG model to simulate turbulence. The improved design of the CWC includes the investigations of the flow guiding vane at the turning corners and the contraction section in the flow acceleration zone. The turning vane cross-sectional shape, the straight-edged length of the wing, and the layout of the contraction transition section design were considered and verified. The obtained results show that the wing-type turning vane with appropriate straight-edged length can help to improve the velocity uniformity of the flow field. The Witozinsky transition curve could achieve better pressure gradient effects for CWC contraction section design, and the flow uniformity improved by increasing the contraction transition length. Based on the optimal design, the internal flow characteristics of the circulating water channel have been greatly improved, laying a solid foundation for wind-wave-current multifunction CWC equipment applications for future experiments.

Tao Zhang, Yumei Li, Hui Lu et al.

The radial jet drilling (RJD) is a key technology to improve the development efficiency of low-permeability oil and gas resources. In order to seek a reasonable hydraulic engineering parameter combination of hydraulic radial jet drilling, to obtain the optimal hydraulic energy distribution, a jet radial horizontal drilling simulation experiment system of the casing windowing is designed. A sequence of experimental investigations focused on engineering parameters of pump displacement, rotating speed, and frequency of high-pressure plunger pump is performed, and the operability and the feasibility of the experiment are verified. To evaluate the maximum drillable length and the self-propelled force of a jet nozzle, a 3D numerical model based on ANSYS-CFX is developed to evaluate the effects of the inlet flow displacement, the flow rates ratio K, and the angle ratio F:B of the forward orifice and backward orifice of the jet nozzle on its maximum drillable length and self-propelled force by sensitivity analysis. Finally, the comparison of numerical simulation results (Ln), mathematical results (Lm), and experiment results (Le) of the maximum drillable length are presented. It is observed that the simulation results are consistent with the experiment results with an average accuracy of 97.07%. Therefore, the proposed numerical model has a good performance in predicting the maximum drillable length of the multiorifice nozzle. The research results can provide theoretical guidance for improving the rock breaking and drilling capability of radial jet drilling technology.

XIE Yi-fan 1, 2, XIE Zhen-ze 1, 2, WU Ji-chun 3, ZHANG Wei 4, XIE Chun-hong 5, LU Chun-hui 1, 2, 6

The traditional finite element method often requires fine element grids to describle the heterogeneity of medium to ensure the accuracy for numerical modeling of groundwater, which leads to a large amount of calculation consumption. The multiscale finite element method can alleviate this problem, but it still needs a high cost to formulate the basis function when dealing with high computational complexity. A multiscale finite element method-triple grid model (MSFEM-T) is proposed for the simulation of groundwater flows. The MSFEM-T introduces an intermediate grid between the coarse grid and the fine grid, so that the basis function in the coarse grid can be established using the MSFEM instead of the FEM based on the intermediate and fine grids, therefore reducing the construction consumption of the basis function and improving the overall calculation efficiency. Moreover, the MSFEM-T uses an over-sampling method based on the coarse, intermediate and fine grids, which can further improve its calculation accuracy. The results show that the accuracy of the MSFEM-T is similar to that of the MSFEM and the finite element method of fine elements (LFEM-F), but the computational efficiency is much higher.

Songbai Li, Changrong Shen, Tao Sun et al.

Based on the Reynolds time mean N-S equation and standard k-ε turbulence model and using Computational Fluid Dynamics technology, this study aims to integrate the brake pump to carry out numerical simulation. Through the adoption of different arrangements of impending height and spacing, the hydraulic characteristics of the full tubular pump unit are analyzed. The two-dimensional streamline, velocity and pressure distribution, and three-dimensional streamline, axial velocity and vorticity distribution of the front pool of each scheme are displayed. The results show that the recommended pump installation height is 0.8 <i>D</i>_d, the maximum limit value of the pump station design specification; in the dual-pump mode, the recommended pump spacing is 2.00 <i>D</i>_s.