Journal articles: 'Hydraulic'

1

Ferguson, R. I. "Hydraulics and hydraulic geometry." Progress in Physical Geography: Earth and Environment 10, no. 1 (March 1986): 1–31. http://dx.doi.org/10.1177/030913338601000101.

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Gisonni, Corrado. "Applied Hydraulics and Hydraulic Structures." Journal of Applied Water Engineering and Research 3, no. 1 (January 2, 2015): 1–2. http://dx.doi.org/10.1080/23249676.2015.1031981.

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Zhong, Xiang Qiang, and Li Dong Liang. "Mechanical-Hydraulic Coupling Simulation for Hydraulic Excavator Working Mechanism." Advanced Materials Research 538-541 (June 2012): 494–97. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.494.

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Hydraulic excavator is a typical and complicated engineering machine by combination of mechanical, control and hydraulic system. It is very important for coupling analysis by use of multiple simulation tools. Hydraulic excavator mechanical model was constructed based on Pro/E 4.0. Virtual prototype of hydraulic excavator was finished by use of ADAMS interface function and carried on a lot of kinematics and dynamics simulation analysis. Hydraulic cylinder circuit was derivated based on ADAMS/Hydraulics. Working principle of bucket arm hydraulic cylinder was analyzed. Mechanical and hydraulic simulation of bucket rod hydraulic cylinder was finished. Bucket rod hydraulic cylinder velocity was obtained. Simulation results show coupling simulations have certain theory value and practical significance. They can provide evidence for trial and optimization of physical prototype.

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Järvelä, Juha, and Terhi Helmiö. "Hydraulic considerations in restoring boreal streams." Hydrology Research 35, no. 3 (June 1, 2004): 223–35. http://dx.doi.org/10.2166/nh.2004.0016.

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The physical habitat that controls ecosystem functioning is determined by local hydraulics and channel morphology. Hydraulic field studies were conducted in a boreal stream (1) to test the hypothesis that the local hydraulic conditions are determined by cross-sectional geometry and flow resistance in boreal conditions by analysing the relationship between flow velocities, cross-sectional geometry and flow resistance, and (2) to suggest success criteria for the restoration of local hydraulic conditions. Results suggest that, in the case of small channels, cross-sectional geometry and flow resistance are weakly interconnected and influenced by factors such as local roughness elements and channel forms. The study showed that both flow resistance and cross-sectional geometry are vital factors in determining local hydraulics. In stream restoration, a design based on consideration of only one of these two factors is inadequate and may result in a failure to replicate natural hydraulic conditions. Simple success criteria for the restoration of local hydraulics are developed.

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Christoffersen, Bradley O., Manuel Gloor, Sophie Fauset, Nikolaos M. Fyllas, David R. Galbraith, Timothy R. Baker, Bart Kruijt, et al. "Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro)." Geoscientific Model Development 9, no. 11 (November 24, 2016): 4227–55. http://dx.doi.org/10.5194/gmd-9-4227-2016.

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Abstract. Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point πtlp, bulk elastic modulus ε, hydraulic capacitance Cft, xylem hydraulic conductivity ks,max, water potential at 50 % loss of conductivity for both xylem (P50,x) and stomata (P50,gs), and the leaf : sapwood area ratio Al : As). We embedded this plant hydraulics model within a trait forest simulator (TFS) that models light environments of individual trees and their upper boundary conditions (transpiration), as well as providing a means for parameterizing variation in hydraulic traits among individuals. We synthesized literature and existing databases to parameterize all hydraulic traits as a function of stem and leaf traits, including wood density (WD), leaf mass per area (LMA), and photosynthetic capacity (Amax), and evaluated the coupled model (called TFS v.1-Hydro) predictions, against observed diurnal and seasonal variability in stem and leaf water potential as well as stand-scaled sap flux. Our hydraulic trait synthesis revealed coordination among leaf and xylem hydraulic traits and statistically significant relationships of most hydraulic traits with more easily measured plant traits. Using the most informative empirical trait–trait relationships derived from this synthesis, TFS v.1-Hydro successfully captured individual variation in leaf and stem water potential due to increasing tree size and light environment, with model representation of hydraulic architecture and plant traits exerting primary and secondary controls, respectively, on the fidelity of model predictions. The plant hydraulics model made substantial improvements to simulations of total ecosystem transpiration. Remaining uncertainties and limitations of the trait paradigm for plant hydraulics modeling are highlighted.

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Windisch, Étienne J. "The hydraulics problem in slope stability analysis." Canadian Geotechnical Journal 28, no. 6 (December 1, 1991): 903–9. http://dx.doi.org/10.1139/t91-107.

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Hydraulic pressures and forces are obtained on a typical slice, as used in current methods of slope stability analysis, under hydrostatic and flowing groundwater conditions. It is shown that current methods do not satisfy some basic hydraulics and soil mechanics principles. The effective normal stress on the lower boundary of a slice is shown to be underestimated, and the resultant hydraulic force is not accounted for adequately. Key words: effective stress, hydraulic pressure, hydraulic gradient, hydraulic force, slope stability.

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Shallat, Todd, and Gunther Garbrecht. "Hydraulics and Hydraulic Research: A Historical Review." Technology and Culture 29, no. 4 (October 1988): 950. http://dx.doi.org/10.2307/3105074.

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Parekh, Siddharth, Ali Pilehvari, and Robert Serth. "Prediction of Fluid Behavior Using Generalized Hydraulic Calculation Method in Hydraulic Fractures." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 81, no. 1 (March 5, 2021): 120–30. http://dx.doi.org/10.37934/arfmts.81.1.120130.

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Hydraulic fracturing has been used as one of the stimulation techniques to economically increase oil and gas production by creating small cracks in subsurface geologic formations to allow oil or gas to move toward a producing well. Hydraulics plays a vital role in many oil field operations including drilling, completion, fracturing and production. In the case of fracturing, however, the role of hydraulics becomes important since optimized hydraulics can minimize the cost and conversely, any miscalculations may cause problems such as the fluid loss or may potentially even lead to loss of the well. The current methods of the hydraulic calculation for non-Newtonian fluids necessitate determination of the robust model. This paper presented a new method for calculating pressure losses in the hydraulic fractures. The objective of this study was to develop the generalized model for hydraulic calculation for non-Newtonian fluid and run the case studies for the model validation. In the present work, detailed algorithm for the hydraulic calculation has been developed and then programmed in C++. The only input to the program is the raw rheological data, shear stress versus shear rate and the geometrical characteristics of the slit. Model validation with the new method has established a very small percentage difference between the values predicted by the model and experimental data. The results demonstrate that the new method is accurately predicting the pressure drop in both laminar and turbulent flow regimes. It is shown that the fluid behavior is more accurately represented using the new method than that with the standard fluid models available in the petroleum industry. Further validation and development to be carried out using experimental data for variety of fluid types.

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Abduazizov, N. A., Zh B. Toshov, and A. Sh Zhuraev. "THE RESEARCH OF "HYDROBANK-COOLER" SYSTEMS OF HYDRAULIC POWER UNITS OF HYDRAULIC MINING MACHINES." EurasianUnionScientists 4, no. 2(71) (2020): 4–8. http://dx.doi.org/10.31618/esu.2413-9335.2020.4.71.598.

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Today, powerful expensive equipment is used in mining enterprises. Downtime, breakdowns and repairs of hydraulic mining machines lead to large financial losses of mining enterprises. Mechanical particles, microdroplets of water and air bubbles that fall into hydraulic fluids during operation, significantly affect the properties of the working fluid. In this regard, maintaining the quality of the working fluid used in expensive hydraulic mining machines is one of the most important tasks of modern hydraulics.

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Javaux, Mathieu, and Andrea Carminati. "Soil hydraulics affect the degree of isohydricity." Plant Physiology 186, no. 3 (March 31, 2021): 1378–81. http://dx.doi.org/10.1093/plphys/kiab154.

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A soil–plant hydraulic model shows that the degree of isohydricity is constrained by below-ground hydraulic limitations and that the shape of plant water potential (WP) curve depends on soil hydraulics.

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Paswan, Ramashankar, Jayanta Das, N. Kumar, Ajit Kumar, Santosh Kumar Mishra, and Kumar Sujit. "Hydraulic Circuit in Damper: An Overview." Applied Mechanics and Materials 592-594 (July 2014): 2056–60. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.2056.

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A Hydraulic circuit is a group of components such as pumps, actuators, and control valves so arranged that they will perform a useful task. When analyzing or designing a hydraulic circuit, the following three important considerations must be taken into account.Safety of operation,Performance of desired function, Efficiency of operation.It is very important for the fluid power ( Hydraulics and Pneumatics ) designer to have a working knowledge of components and how they operate in a circuit. Hydraulic circuits are developed through the use of graphical symbols for all components. Keywords: damper,hydraulic circuit,

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Arifjanov, Aybek. "Hydraulic Friction Coefficient at Hydraulic Mixing Movement in Pressure Pipelines." Journal of Advanced Research in Dynamical and Control Systems 12, SP7 (July 25, 2020): 1332–36. http://dx.doi.org/10.5373/jardcs/v12sp7/20202233.

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Yan, Bing Bing, Wen Bo Ren, Bao Lin Yin, and Yang Li. "Hydraulic System Simulation of 3-UPS Parallel Mechanism Based on ADAMS/Hydraulics." Key Engineering Materials 579-580 (September 2013): 430–33. http://dx.doi.org/10.4028/www.scientific.net/kem.579-580.430.

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In order to guaranty the work stability of the move-in-mud robot and movement relationship of wriggle turning joint, to use the 3-UPS parallel mechanism as the steering joint. Make full use of the characteristics flexibility, heavy force loading and small workspace of the parallel mechanism. Supporting link of the parallel mechanism driven by hydraulic cylinders, so a completely hydraulic system is an important factor to ensure the stationary work of parallel mechanism, provide the required power to go forward and ensure the forward speed of the move-in-mud robot. Establish the virtual prototype model of mechanical-hydraulic coupling system by using of Pro/E and ADAMS/Hydraulics software, do the dynamic simulation analysis of hydraulic control system based on Hydraulics module, the simulation process can be made more visual and vivid by three-dimensional visualization. Obtain the platform speed and hydraulic cylinder pressure curve after simulation, compare simulation results with theoretical calculations, and verify that the design is reasonable. The results show that it lays the foundation for the further optimization and research of the move-in-mud robot.

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Unterholzner, Lucrezia, Marco Carrer, Andreas Bär, Barbara Beikircher, Birgit Dämon, Adriano Losso, Angela Luisa Prendin, and Stefan Mayr. "Juniperus communis populations exhibit low variability in hydraulic safety and efficiency." Tree Physiology 40, no. 12 (August 12, 2020): 1668–79. http://dx.doi.org/10.1093/treephys/tpaa103.

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Abstract The performance and distribution of woody species strongly depend on their adjustment to environmental conditions based on genotypic and phenotypic properties. Since more intense and frequent drought events are expected due to climate change, xylem hydraulic traits will play a key role under future conditions, and thus, knowledge of hydraulic variability is of key importance. In this study, we aimed to investigate the variability in hydraulic safety and efficiency of the conifer shrub Juniperus communis based on analyses along an elevational transect and a common garden approach. We studied (i) juniper plants growing between 700 and 2000 m a.s.l. Innsbruck, Austria, and (ii) plants grown in the Innsbruck botanical garden (Austria) from seeds collected at different sites across Europe (France, Austria, Ireland, Germany and Sweden). Due to contrasting environmental conditions at different elevation and provenance sites and the wide geographical study area, pronounced variation in xylem hydraulics was expected. Vulnerability to drought-induced embolisms (hydraulic safety) was assessed via the Cavitron and ultrasonic acoustic emission techniques, and the specific hydraulic conductivity (hydraulic efficiency) via flow measurements. Contrary to our hypothesis, relevant variability in hydraulic safety and efficiency was neither observed across elevations, indicating a low phenotypic variation, nor between provenances, despite expected genotypic differences. Interestingly, the provenance from the most humid and warmest site (Ireland) and the northernmost provenance (Sweden) showed the highest and the lowest embolism resistance, respectively. The hydraulic conductivity was correlated with plant height, which indicates that observed variation in hydraulic traits was mainly related to morphological differences between plants. We encourage future studies to underlie anatomical traits and the role of hydraulics for the broad ecological amplitude of J. communis.

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15

Ozalp, A. F., R. Polat, C. Cetinkaya, and M. H. Cetin. "Investigation of a Digital Hydraulic Valve Operated by Servo Motors." Engineering, Technology & Applied Science Research 11, no. 6 (December 11, 2021): 7957–63. http://dx.doi.org/10.48084/etasr.4598.

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This paper describes a new type of digital hydraulic valve run by two servo motors. Digital hydraulics is a cutting-edge technology, which saves more exhausted energy than conventional hydraulic valves. It includes conventional valves, but its working principle is different. Similar or different size valves constitute a digital hydraulic valve assembly. When the assigned valves are opened, a certain amount of flow is obtained from the output of the valve assembly. To control a digital hydraulic valve, Pulse Number Modulation (PNM) Control technique is used for equal valve flow rates, while Pulse Code Modulation (PCM) is used for different valve flow rates. Valves are exerted by independently launched electric coils. Previous studies used controller board and external power booster circuits for coils. In this study, a new type of digital hydraulic valve is designed, manufactured, and tested with the PNM method. The studied valve body has two different valve groups. Every group includes 16 equal valves and 1 camshaft rotated by 1 servo motor. The servo motors are controlled by a PLC. The calculated performance index is found to be 5.1ms which is similar to the results of previous studies. The experimental results showed that the cam and servo motor controlled digital hydraulics is applicable to variable speed control hydraulic systems.

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Nikora, V. I., D. G. Goring, and B. J. F. Biggs. "Silverstream eco‐hydraulics flume: Hydraulic design and tests." New Zealand Journal of Marine and Freshwater Research 32, no. 4 (December 1998): 607–20. http://dx.doi.org/10.1080/00288330.1998.9516848.

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Marcinek, Milan, and Iveta Marková. "Working Effectiveness of Hydraulic Rescue Equipments for Firefighters." Advanced Materials Research 1001 (August 2014): 517–25. http://dx.doi.org/10.4028/www.scientific.net/amr.1001.517.

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Author deals with the topic relating to use of hydraulic extrication tools at technical interventions in the field of person extrication and closer characterizes individual technical items. He characterizes material and technical equipage of responding units and emphasizes a need of systematic solving of each extraordinary emergency situation relating to persons extrication. The aim of paper is research of safe use of a method of DVT when cutting column B within the intervention of a traffic accident on the selected car. For the purpose of research are realized of comparison of times required for opening and closing of selected types of hydraulic. There are use hydraulic shears Holmatro ® CU 3040 NCTM, hydraulic shears Holmatro ® CU 4035 C, hydraulic shears Weber Hydraulik S-260.

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Mohammed, Jamal AK, Walaa M. Hashim, and Bahaa S. Beram. "Performance Improvement of a Conventional Hydraulic Elevator by Using Electro-Hydraulic Servo Mechanism." Engineering and Technology Journal 38, no. 5A (May 25, 2020): 748–60. http://dx.doi.org/10.30684/etj.v38i5a.367.

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An electro-hydraulic elevator is a new type of enhanced elevators that are used in low-rise buildings that do not exceed more than three floors. In this paper, an electro-hydraulic servo system for controlling the speed of a hydraulic elevator prototype by using a proportional valve and PID controller was investigated theoretically and experimentally. A three floors elevator prototype model with 76cm height was built including hydraulics components and electrical components. The elevator system is fully automated using the Arduino UNO board based Data Acquisition (DAQ) system. LabVIEW software is used to control the hydraulic elevator system through L298 DC drive via the DAQ board. The best PID gains was obtained experimentally. The elevator system prototype could be emplimented for educational purposes; such as learning the undergraduate students in the Electromechanical Engineering Department in the University of Technology how to structuring the electro-hydraulic elevator as well as the appropriate control strategy.

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Hotchkiss, Rollin H., Patrick J. Flanagan, and Kevin Donahoo. "Hydraulic Jumps in Broken-Back Culverts." Transportation Research Record: Journal of the Transportation Research Board 1851, no. 1 (January 2003): 35–44. http://dx.doi.org/10.3141/1851-04.

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A broken-back culvert has one or more changes in grade within the prismatic barrel profile. One section of a broken-back culvert is usually steep, with the steep slope contributing to high outlet velocities unless a hydraulic jump forms upstream from the culvert outlet. Predictive equations have been published for a wide range of experimental conditions but still do not describe the hydraulics of a jump as it traverses the steeply sloped section and the most downstream section of a broken-back culvert. A computer program, the Broken-Back Culvert Analysis Program (BCAP), analyzes the hydraulics of circular or box-shaped broken-back culverts and provides a comprehensive design tool for engineers. It predicts whether a hydraulic jump will occur and, if so, where it begins and ends. Analyses are performed for 10 discharges. Outputs include rating curves for headwater and outlet depths and outlet velocity and tabulations of hydraulic parameters for each discharge. The water surface profiles throughout the culvert, except through the hydraulic jump, are computed and are plotted on the screen. Experiments were performed with model culverts to assess the accuracy of the predictive equations in BCAP for headwater depth, the location of a hydraulic jump, and the hydraulic jump length. The predictions for the headwater depth at the culvert inlet matched the experimental observations well, but predictions for hydraulic jump location and length were less satisfactory. BCAP has been used for hundreds of design projects in Nebraska and has been downloaded almost 300 times from at least 22 different states. It is recommended that BCAP be improved as better experimental data become available.

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Prudovskii, A. M., V. B. Rodionov, and I. S. Ronzhin. "Hydraulic research in hydraulic engineering." Hydrotechnical Construction 33, no. 8-9 (August 1999): 452–58. http://dx.doi.org/10.1007/bf02801084.

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Ganthaler, Andrea, and S. Mayr. "Vaccinium gaultherioides: Another insight into water relations of alpine dwarf shrubs." Journal of Plant Hydraulics 2 (November 17, 2015): e004. http://dx.doi.org/10.20870/jph.2015.e004.

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Dwarf shrubs exhibit different requirements for a safe and efficient water supply compared to trees due their basitonic branching and low growth height. Though, only few studies dealt with the hydraulics of this growth form. Here we report key hydraulic parameters (vulnerability to drought-induced embolism, xylem hydraulic conductivity, cell osmotic potential, potential at turgor loss point) and related wood anatomical traits for Vaccinium gaultherioides, a wide-spread species in the European Alps. The results affirm the current knowledge, by indicating a relatively risky hydraulic strategy with low hydraulic safety compared to alpine trees and osmotic properties connected to the species’ soil humidity requirements.

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Yan, Tanbao, Peng Li, and Wei Niu. "Research on Modeling Technology of Aircraft Hydraulic System Based on AMESim." Journal of Physics: Conference Series 2183, no. 1 (January 1, 2022): 012007. http://dx.doi.org/10.1088/1742-6596/2183/1/012007.

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Abstract With the development of electro-hydraulic integration technology, the control accuracy, complexity and dynamic response characteristics of aircraft hydraulic system actions have become a hot topic in the field of hydraulics. The traditional hydraulic system design method mainly uses the designer’s knowledge and experience to construct a dynamic system with real components, and then tests on the system, this method is more difficult to adjust parameters. Therefore, taking the hydraulic system of an aircraft as an example, the simulation model of each component of the system is established by using modeling and simulation technology and graphical modeling method, so as to provide support for aircraft fault diagnosis and prediction.

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Wang, Huan Yun, Li Ma, and Xiu Fen Liu. "Analysis and Elimination of Common Faults of Hydraulic System." Advanced Materials Research 694-697 (May 2013): 601–4. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.601.

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In order to ensure the normal operation of the hydraulic system, the faults must be found and eliminated promptly and accurately. Most of the faults of hydraulic system don’t happen suddenly. generally, there are signs such as noise, vibration, lash, pollution and leakage etc.. If these phenomena can be found, controlled and eliminated promptly and properly, the system faults can be reduced accordingly. This paper introduces several common faults of hydraulic system and the elimination methods. which the hydraulics technicians can refer to.

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Hasanov, I. R., and M. A. Jamalbayov. "Specification of hydraulic resistance while gas filtration in porous medium in linear and filtration laws." Azerbaijan Oil Industry, no. 01 (January 15, 2022): 21–23. http://dx.doi.org/10.37474/0365-8554/2022-1-21-23.

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As it is known, unlike the formula for hydraulic resistance in reservoir conditions, there are numerous for tube hydraulics. Hydraulic resistance and Reynolds number are important characteristics of flow while gas filtration in porous medium. In this view, their specification is essential while hydrodynamic calculations and modeling of gas filtration in such a medium in reservoir conditions. The formula for the specification of hydraulic resistance coefficient both in linear and binomial filtration law, as well as those for Reynolds number depending on them have been obtained.

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Azzam, Israa, Keith Pate, Jose Garcia-Bravo, and Farid Breidi. "Energy Savings in Hydraulic Hybrid Transmissions through Digital Hydraulics Technology." Energies 15, no. 4 (February 13, 2022): 1348. http://dx.doi.org/10.3390/en15041348.

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Hydraulic hybrid drivetrains, which are fluid power technologies implemented in automobiles, present a popular alternative to conventional drivetrain architectures due to their high energy savings, flexibility in power transmission, and ease of operation. Hydraulic hybrid drivetrains offer multiple environmental benefits compared to other power transmission technologies. They provide heavy-duty vehicles, e.g., commercial transportation, construction equipment, wagon handling, drilling machines, and military trucks, with the potential to achieve better fuel economy and lower carbon emissions. Despite the preponderance of hydraulic hybrid transmissions, state-of-the-art hydraulic hybrid drivetrains have relatively low efficiencies, around 64% to 81%. This low efficiency is due to the utilization of conventional variable displacement pumps and motors that experience high power losses throughout the drive cycle and thus fail to maintain high operating efficiency at lower volumetric displacements. This work proposes and validates a new methodology to improve the overall efficiency of hydraulic hybrid drivetrains by replacing conventional pump/motor units with their digital counterparts. Compared to conventional pump/motors, the digital pump/motor can achieve higher overall efficiencies at a wide range of operating conditions. A proof-of-concept digital pump/motor prototype was built and tested. The experimental data were integrated into a multi-domain physics-based simulation model of a series hydraulic hybrid transmission. The proposed methodology permits enhancing the overall efficiency of a series hydraulic hybrid transmission and thus allows for energy savings. Simulating the system at moderate load-speed conditions allowed achieving a total efficiency of around 89%. Compared to the average efficiency of the series hydraulic hybrid drivetrains, our simulation results reveal that the utilization of the state-of-the-art digital pump enables improving the total efficiency of the series hydraulic hybrid drivetrain by up to 25%.

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Tanaka, Yutaka, and Hiroshi Yoshinada. "Special Issue on Sustainable Design for Hydraulic Systems." International Journal of Automation Technology 6, no. 4 (July 5, 2012): 409. http://dx.doi.org/10.20965/ijat.2012.p0409.

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Given the high human impact on the environment, whether intentional or not, the world now faces a situation in which industrial development cannot proceed further without harmony among human beings and the environment. Hydraulic technologies have matured in the last decade and new technologies have emerged related to information technology, energy saving, mechatronics, and water hydraulics. It is our view that innovations in hydraulic technology involving sustainable design for hydraulic systems are essential for sustainably developing fluid power technology. One reason for this special issue on Sustainable Design for Hydraulic Systems is to encourage incremental breakthroughs in research based upon existing foundations. Another reason is to expand coordination and cooperation among academic and industrial researchers and institutions to realize these innovations. This special issue covers recent developments in hydraulic technologies, including water hydraulics and functional fluids, basic research, applications and case studies. State-of-the-art papers on hydraulic systems and components place special emphasis on industrial applications and their engineering background. All of the papers in this special issue are of great interest and value in sustainably designing fluid power systems, and we are sure that these papers will contribute much to the further development of fluid power technology. We sincerely thank the authors for their submissions and the reviewers for their invaluable efforts, without which this special issue would not have been possible. We are most grateful to all who have contributed their time and effort to ensuring the success of this special issue.

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Toca, Andrei, Pedro Villar-Salvador, Juan A. Oliet, and Douglass F. Jacobs. "Normalization criteria determine the interpretation of nitrogen effects on the root hydraulics of pine seedlings." Tree Physiology 40, no. 10 (June 1, 2020): 1381–91. http://dx.doi.org/10.1093/treephys/tpaa068.

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Abstract Plant hydraulics is key for plant survival and growth because it is linked to gas exchange and drought resistance. Although the environment influences plant hydraulics, there is no clear consensus on the effect of nitrogen (N) supply, which may be, in part, due to different hydraulic conductance normalization criteria and studied species. The objective of this study was to compare the variation of root hydraulic properties using several normalization criteria in four pine species in response to three contrasting N fertilization regimes. We studied four closely related, yet ecologically distinct species: Pinus nigra J.F. Arnold, Pinus pinaster Ait., Pinus pinea L. and Pinus halepensis Mill. Root hydraulic conductance (Kh) was measured with a high-pressure flow meter, and values were normalized by total leaf area (leaf specific conductance, Kl), xylem cross-section area (xylem specific conductance, Ks), total root area (root specific conductance, Kr) and the area of fine roots (fine root specific conductance, Kfr). Controlling for organ size differences allowed comparison of the hydraulic efficiency of roots to supply or absorb water among fertilization treatments and species. The effect of N on the root hydraulic efficiency depended on the normalization criteria. Increasing N availability reduced Kl and Ks, but increased Kh, Kr and especially Kfr. The positive effect of N on Kr and Kfr was positively related to seedling relative growth rate and was also consistent with published results at the interspecific level, whereby plant hydraulics is positively linked to photosynthesis and transpiration rate and fast growth. In contrast, normalization by leaf area and xylem cross-sectional area (Kl and Ks) reflected opposite responses to Kr and Kfr. This indicates that the normalization criteria determine the interpretation of the effect of N on plant hydraulics, which can limit species and treatment comparisons.

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Jin, Ying, Chuankuan Wang, Zhenghu Zhou, and Zhimin Li. "Co-ordinated performance of leaf hydraulics and economics in 10 Chinese temperate tree species." Functional Plant Biology 43, no. 11 (2016): 1082. http://dx.doi.org/10.1071/fp16097.

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Exploring relationships between leaf hydraulics and economic traits is important in understanding the carbon–water coupling and in extending the leaf economics spectrum. In this study, leaf hydraulics, photosynthesis, structural and nutrient traits and photosynthetic resource use efficiency were measured for 10 temperate tree species in the north-eastern China. Leaf hydraulic conductance was positively correlated with photosynthetic traits, specific leaf area, leaf nitrogen concentration, photosynthetic water and nitrogen use efficiencies, suggesting co-ordination between leaf hydraulics and economic traits. Principal component analysis revealed that significant correlations existed among leaf hydraulic, photosynthetic and resource use traits (axis 1), and axis 2 was strongly associated with leaf structural and nutrient traits. The 10 species were distributed along the diagonal line between axis 1 and axis 2. Species displaying the ‘fast’ strategy tended to have higher photosynthetic rates, leaf hydraulic conductance and photosynthetic water and nutrient use efficiencies; however, they also had lower carbon investment and faced a greater risk of embolism. These findings indicate that leaf hydraulics, economics and resource uses together play an important role in determining species ecological strategies, and provide supports for the ‘fast–slow’ leaf economics spectrum.

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Frąckowiak, Damian. "Simulation study of the hydraulic transmitter-receiver system." MATEC Web of Conferences 254 (2019): 03001. http://dx.doi.org/10.1051/matecconf/201925403001.

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The paper presents a hydraulic transmitter receiver system which is characterized by the ability to remotely send information utilizing a single hydraulic line. The system was subject to computer simulation in the software Fluid-SIM Hydraulics, and based on the obtained measurement results the influence of the parameters of its components on the correct operation of the entire system was determined.

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Richardson, Freya, Gregory J. Jordan, and Timothy J. Brodribb. "Leaf hydraulic conductance is linked to leaf symmetry in bifacial, amphistomatic leaves of sunflower." Journal of Experimental Botany 71, no. 9 (January 23, 2020): 2808–16. http://dx.doi.org/10.1093/jxb/eraa035.

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Abstract The hydraulic implications of stomatal positioning across leaf surfaces and the impact on internal water flow through amphistomatic leaves are not currently well understood. Amphistomaty potentially provides hydraulic efficiencies if the majority of hydraulic resistance in the leaf exists outside the xylem in the mesophyll. Such a scenario would mean that the same xylem network could equally supply a hypostomatic or amphistomatic leaf. Here we examine leaves of Helianthus annuus to determine whether amphistomaty in this species is associated with higher hydraulic efficiency compared with hypostomatic leaves. We identified asymmetry in the positioning of minor veins which were significantly closer to the abaxial than the adaxial leaf surface, combined with lower Kleaf when transpiration was driven through the adaxial rather than the abaxial surface. We also identified a degree of coordination in stomatal behaviour driven by leaf hydraulics, where the hydraulic conditions experienced by an individual leaf surface affected the stomatal behaviour on the opposite surface. We found no advantage to amphistomaty based on efficiencies in construction costs of the venous system, represented by vein density:stomatal density, only limited hydraulic independence between leaf surfaces. These results suggest that amphistomaty does not substantially increase whole-leaf hydraulic efficiency.

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Schick, Tobias, Jochen Hörer, Klaus Ellenrieder, Karl-Heinz Blum, and Katharina Schmitz. "Sensitivity analysis of operating parameters in hydraulic systems with respect to the aging of hydraulic fluids." Tribologie und Schmierungstechnik 69, eOnly Sonderausgabe (November 18, 2022): 25–29. http://dx.doi.org/10.24053/tus-2022-0028.

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In this work, a novel oil aging test-rig based on a real hydraulic system is introduced. This device allows an accelerated fluid-aging rate under high hydraulic loads. Furthermore, it is possible to vary the operating parameters to evaluate the different factors that influence the aging behavior of hydraulic fluids. Oil samples, which are aged under different conditions, are analyzed using FTIR to estimate the rate of aging using the degradation process of Zinc dialkyl dithiophosphate (ZDDP). The results show a clear aging behavior dependent on different operating parameters in hydraulics. In addition to the degradation of ZDDP, the depletion of the phenolic antioxidant (AO) and the formation of a varnish film on metallic surfaces can be observed.

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Wang, Hua Bing, and Jun Ke Hu. "Durability Testing System with Power Recycle for the Variable Displacement Closed-Loop Hydraulic Pumps." Applied Mechanics and Materials 241-244 (December 2012): 1333–37. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.1333.

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A testing system scheme with power recycle for hydraulic pumps’ durability is present, which is based on a hydraulic motor with hydraulicly overridden pressure compensation. The hydraulic motor can adaptively adjust its displacement to meet the demand of displacement match of the power feedback in the system. The system pressure can be set by adjusting the starting control pressure of the motor. The rotating speed of the pump is guaranteed by the control of the driven electrical motor. A hydraulic bridge unit is used to guide the flow from the outport of the pump to the fixed inlet port of the hydraulic motor and thus causes the motor to rotate in a certain direction to drive the pump in order to recycle the power.

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Biswas, Biswajit, and Balai Chandra Das. "Hydraulic Parameters and Morphometric Variables Interactions in Bedrock Channel." Quaestiones Geographicae 35, no. 3 (September 1, 2016): 75–88. http://dx.doi.org/10.1515/quageo-2016-0028.

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Abstract Present study is on the interdependent nature of hydraulic parameters and morphometric variables of a bedrock river. In this study, using dumpy level, GPS, satellite images and some mathematical equations a data set on hydraulics and morphometric variables of a bedrock channel, named Bhatajhor, of eastern India was generated. That data set was used to (1) find out impulse-response relations between hydraulic variables (2) find out relations between morphometric variables and (3) find out relations between hydraulic and morphometric variables. Seven equations (5–11) were formulated based on this empirical study to the end. The seven empirical relations, most of which include only two variables, involve channel cross-section dimensions (area, width, mean depth, maximum depth, width/depth ratio, hydraulic radius), slope and hydraulic variables (velocity, kinetic energy, stream power, Manning’s n factor, Chezy’s C factor and shear stress). Observation shows relatively higher coefficient of determination (R2) between variables like velocity and Manning’s n factor (0.67), velocity and Chezy’s C factor (0.67), slope and τ (0.89), w/d ratio and hydraulic radius (0.53), slope and w/d ratio (0.50).

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34

Dickey, Frances. "“Hydraulic”." T. S. Eliot Studies Annual 3, no. 1 (July 1, 2021): 235–40. http://dx.doi.org/10.3828/tsesa.2021.vol3.22.

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35

Tung, Yeou-Koung. "Probabilistic hydraulic design: A next step to experimental hydraulics." Journal of Hydraulic Research 32, no. 3 (May 1994): 323–36. http://dx.doi.org/10.1080/00221689409498736.

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Killworth, Peter D. "Hydraulic control and maximal flow in rotating stratified hydraulics." Deep Sea Research Part I: Oceanographic Research Papers 42, no. 6 (June 1995): 859–71. http://dx.doi.org/10.1016/0967-0637(95)00032-2.

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Killworth, P. "Hydraulic control and maximal flow in rotating stratified hydraulics." International Journal of Multiphase Flow 22 (December 1996): 106. http://dx.doi.org/10.1016/s0301-9322(97)88238-9.

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38

Sui, Jueyi. "Fluvial Hydraulics Affected by River Ice and Hydraulic Structures." Water 15, no. 7 (March 23, 2023): 1262. http://dx.doi.org/10.3390/w15071262.

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Ivetić, Damjan, Željko Vasilić, Miloš Stanić, and Dušan Prodanović. "Speeding up the water distribution network design optimization using the ΔQ method." Journal of Hydroinformatics 18, no. 1 (January 21, 2015): 33–48. http://dx.doi.org/10.2166/hydro.2015.118.

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To optimize the design of a water distribution network (WDN), a large number of possible solutions need to be examined; hence computation efficiency is an important issue. To accelerate the computation, one can use more powerful computers, parallel computing systems with adapted hydraulic solvers, hybrid algorithms, more efficient hydraulic methods or any combination of these techniques. This paper explores the possibility to speed up optimization using variations of the ΔQ method to solve the network hydraulics. First, the ΔQ method was used inside the evaluation function where each tested alternative was hydraulically solved and ranked. Then, the convergence criterion was relived in order to reduce the computation time. Although the accuracy of the obtained hydraulic results was reduced, these were feasible and interesting solutions. Another modification was tested, where the ΔQ method was used just once to solve the hydraulics of the initial network, and the unknown flow corrections were added to the list of other unknown variables subject to optimization. Two case networks were used for testing and were compared to the results obtained using EPANET2. The obtained results have shown that the use of the ΔQ method in hydraulic computations can significantly accelerate the optimization of WDN.

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Yurov, V. M. "NITROGENING HYDRAULIC CYLINDER RODS." Eurasian Physical Technical Journal 17, no. 2 (December 24, 2020): 25–30. http://dx.doi.org/10.31489/2020no2/25-30.

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The paper considers the method of ion-plasma nitriding of polished rods of hydraulic cylinders. With ion nitriding, the surface hardening of parts is most pronounced. This is due to the fact that the surface layer of the part does not exceed 20 nm, that is, it is a nanostructure. In this nanostructure, nitrogen diffusion processes are significantly different from bulk ones. The size effects in the nanostructure lead to the fact that the “classical” Fick equations do not work in the layer, and the diffusion of nitrogen in this layer depends logarithmically on the properties of the steel. It was theoretically found that diffusion in a nanoplate depends both on the material of the plate through the diffusion coefficient of the bulk sample D0 and on the size factor α. In the classical case, there is no such dependence.

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Žitný, R., A. Landfeld, J. Skočilas, J. Stancl, V. Flegl, M. Zachariášová, M. Jírů, and M. Houška. "Hydraulic characteristic of collagen." Czech Journal of Food Sciences 33, No. 5 (June 3, 2016): 479–85. http://dx.doi.org/10.17221/62/2015-cjfs.

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Hydraulic characteristic of collagen. Czech J. Food Sci., 33: 479–485. The hysteresis of a hydraulic characteristic while pumping an aqueous solution of collagen through a pipe at gradually increasing and decreasing flow rates (hysteresis means that the pressure drop curve during increased flow rate is above the pressure drop during decreasing flow rate) was observed. The problem was initiated by industry and by demand for an on-line recording of rheological properties of collagenous material used for extrusion of collagen casings. The Herschel-Bulkley rheological model was capable to describe rheograms in a wide range of deformation rates; however it was not able to describe and explain the hysteresis. As a possible reason thixotropic properties were identified and the hydraulic characteristic was calculated using a thixotropic generalisation of the Herschel-Bulkley model. The developed 1D numerical model can be applied for on-line modelling of transient flows of incompressible thixotropic food materials (startup flow) and at a limited range of flow rates it is also capable to describe the hysteresis of hydraulic characteristics.

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Majdan, R., Z. Tkáč, J. Kosiba, R. Abrahám, J. Jablonický, Ľ. Hujo, and M. Mojžiš. "Evaluation of tractor biodegradable hydraulic fluids on the basis of hydraulic pump wear." Research in Agricultural Engineering 59, No. 3 (September 18, 2013): 75–82. http://dx.doi.org/10.17221/18/2012-rae.

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Two types of biodegradable hydraulic fluids (HEES and HEPR) with the mineral oil-based hydraulic fluid (HV) were compared. The tests were performed using a test bench. During the tests with a tractor hydraulic pump, the fluids were loaded by a cyclic pressure load. The tests of fluids were evaluated on the basis of wear of the pump. Evaluation parameters were the flow characteristics of the pump and the cleanliness level of tested fluids. The temperature of the fluid under which the test was performed was measured in real operating conditions of the Zetor Forterra 11441 tractor. It is possible to state upon the test results that the mineral oil-based fluid was classified in the first place, the biodegradable fluid of the HEPR type in the second place, and the biodegradable fluid of the HEES type received the last position.  

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Buriennikov, Yurii, Leonid Kozlov, Oana Rusu, Viktor Matviichuk, Volodymyr Pyliavets, Natalia Semychasnova, and Ioan Rusu. "OPTIMIZATION OF PARAMETERS OF THE MOBILE MACHINE ADAPTIVE HYDRAULIC CIRCUIT." International Journal of Modern Manufacturing Technologies 13, no. 3 (December 25, 2021): 14–21. http://dx.doi.org/10.54684/ijmmt.2021.13.3.14.

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Mobile machine hydraulic circuits tend to adopt electrohydraulics. Such hydraulic circuits are based on controlled pumps, modulated hydraulics, sensors and controllers. This allows adapting the hydraulic circuit operating modes to the changes of external conditions of the machine operation. Application of hydraulic circuits with electrohydraulics in mobile machines allows to use mobile machines efficiently with a high number of removable endangers, increases their performance and improves the quality of performed works. The authors propose an adaptive hydraulic circuit for a mobile machine. The operation process in the adaptive hydraulic circuit in static and dynamic modes is determined by the interaction of the pump controller and pressure differential control valves. The hydraulic system operation stability, its fast response and readjustment are determined by the controller parameters. It has been revealed that the main parameters affecting the dynamic characteristics of the hydraulic system are: throttle area and coefficient of amplifying the pump controller orifice, dampener area and coefficient of amplifying the pressure differential control valve orifice. These parameters affect the stability, controlling and readjustment time in the hydraulic circuit differently. A functional including the values of controlling time , σ controlling and losses in the pump controller was used as an optimization criterion. The optimization has been made according to the developed mathematical model applying the method developed by I. Sobol and R. Statnikov. During the optimization each controller parameter changed on 3 levels. 81 tests were made and the best combination of controller parameters for the optimization criterion was determined. The following hydraulic circuit operation values were reached under the optimal values of parameters = 1.0·10-6 m2, = 1.0·10-3 m, = 1.2·10-6 m2, = 10·10-3 m: = 1.1 с, σ = 32 %, = 0.82 kW that comply with the requirements towards hydraulic circuits of mobile machines.

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Wang, Yujie, and Christian Frankenberg. "Technical note: Common ambiguities in plant hydraulics." Biogeosciences 19, no. 19 (October 5, 2022): 4705–14. http://dx.doi.org/10.5194/bg-19-4705-2022.

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Abstract. Plant hydraulics gains increasing interest in plant ecophysiology and vegetation modeling. However, the hydraulic properties and profiles are often improperly represented, thus leading to biased results and simulations, e.g., the neglection of gravitational pressure drop results in overestimated water flux. We highlight the commonly seen ambiguities and/or misunderstandings in plant hydraulics, including (1) the distinction between water potential and pressure, (2) differences among hydraulic conductance and conductivity, (3) xylem vulnerability curve formulations, (4) model complexity, (5) stomatal-model representations, (6) bias from analytic estimations, (7) whole-plant vulnerability, and (8) neglected temperature dependencies. We recommend careful thinking before using or modifying existing definitions, methods, and models.

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Dermawan, V., D. R. Dermawan, M. J. Ismoyo, and P. H. Wicaksono. "Investigation Of Hydraulic Flow Characteristics On Drop Structures." IOP Conference Series: Earth and Environmental Science 930, no. 1 (December 1, 2021): 012028. http://dx.doi.org/10.1088/1755-1315/930/1/012028.

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Abstract Drop structures are required if the slope of the ground level is steeper than the maximum allowable gradient channel. Drop structures become bigger as height increases. Its hydraulic capability may be reduced due to variations of jets falling on the stilling basin floor due to discharge changing. Drop structures should not be used if the change in energy level exceeds 1.50 m. The free-falling overflow on drop structures will hit the stilling basin and move downstream. As a result of overflows and turbulence in the pool below the nappe, some energy is dissipated at the front. The rest of the energy will be reduced downstream. The objectives of this study are to investigate the hydraulics flow behavior in straight and sloping drop structures and to investigate hydraulics flow behavior in a single and serial vertical drop (stepped drop). The hydraulic model results of single and stepped drop structures are compared to obtain flow behavior and energy dissipation information. The comparisons are specific to the flow parameters, including flow depth at the drop structures toe, flow depth after the jump, and hydraulic jump length.

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Mursinna, A., Erica McCormick, Katie Van Horn, Lisa Sartin, and Ashley Matheny. "Plant Hydraulic Trait Covariation: A Global Meta-Analysis to Reduce Degrees of Freedom in Trait-Based Hydrologic Models." Forests 9, no. 8 (July 25, 2018): 446. http://dx.doi.org/10.3390/f9080446.

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Current vegetation modeling strategies use broad categorizations of plants to estimate transpiration and biomass functions. A significant source of model error stems from vegetation categorizations that are mostly taxonomical with no basis in plant hydraulic strategy and response to changing environmental conditions. Here, we compile hydraulic traits from 355 species around the world to determine trait covariations in order to represent hydraulic strategies. Simple and stepwise regression analyses demonstrate the interconnectedness of multiple vegetative hydraulic traits, specifically, traits defining hydraulic conductivity and vulnerability to embolism with wood density and isohydricity. Drought sensitivity is strongly (Adjusted R2 = 0.52, p < 0.02) predicted by a stepwise linear model combining rooting depth, wood density, and isohydricity. Drought tolerance increased with increasing wood density and anisohydric response, but with decreasing rooting depth. The unexpected response to rooting depth may be due to other tradeoffs within the hydraulic system. Rooting depth was able to be predicted from sapwood specific conductivity and the water potential at 50% loss of conductivity. Interestingly, the influences of biome or growth form do not increase the accuracy of the drought tolerance model and were able to be omitted. Multiple regression analysis revealed 3D trait spaces and tradeoff axes along which species’ hydraulic strategies can be analyzed. These numerical trait spaces can reduce the necessary input to and parameterization of plant hydraulics modules, while increasing the physical representativeness of such simulations.

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Perrin, O., S. Christophe, F. Jacquinod, and O. Payrastre. "VISUAL ANALYSIS OF INCONSISTENCIES IN HYDRAULIC SIMULATION DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B4-2020 (August 25, 2020): 795–801. http://dx.doi.org/10.5194/isprs-archives-xliii-b4-2020-795-2020.

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Abstract. We present our contribution to the geovisualization and visual analysis of hydraulic simulation data, based on an interdisciplinary research work undertaken by researchers in geographic information sciences and in hydraulics. The positive feedback loop between researchers favored the proposal of visualization tools enabling visual reasoning on hydraulic simulated data so as to infer knowledge on the simulation model. We interactively explore and design 2D multi-scale styles to render hydraulic simulated data, in order to support the identification over large simulation domains of possible local inconsistencies related to input simulation data, simulation parameters or simulation workflow. Models have been implemented into QGIS and are reusable for other input data and territories.

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Vorozhtsov, O. V., I. E. Plaksin, and A. V. Trifanov. "Application of gear hydraulic machines in the composition of hydrostatic transmissions." IOP Conference Series: Earth and Environmental Science 979, no. 1 (February 1, 2022): 012023. http://dx.doi.org/10.1088/1755-1315/979/1/012023.

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Abstract Hydraulic machines serve either to impart energy to the fluid flowing through them, or to obtain energy from the fluid for its further useful use. The number of hydraulic machines used in the national economy is increasing annually, due to the fact that, in comparison with electric motors, they have smaller overall dimensions and weight, and also have a higher ratio of torque on the output shaft to the moment of inertia of the rotor. In agriculture, hydraulic machines are widely used in crop production. Through the use of hydraulics and automation, the development of complex mechanization of production processes is carried out, which provides for the development of machines of increased power and reliability. Also, the use of hydraulic machines allows you to relieve the structure of rigid mechanical connections and allows a wide range of adjustment of the unit operation. The most widely used today are two types of hydraulic machines - piston and gear. The use of hydraulic piston machines places high demands on the degree of purification and quality of transmission oil, as well as on the qualifications of technical personnel to ensure quality maintenance. Gear hydraulic machines are less demanding on the purity of the working fluid, as well as simplicity in design, are quite reliable, have a low cost price and a wide range of rotational speeds, in addition, they are able to create a relatively high pressure with low weight. The overall efficiency of gear hydraulic machines, which is 90%, is slightly inferior to that of piston hydraulic machines, which reaches 93%, respectively. The given characteristics of gear hydraulic machines allow us to consider them, taking into account modern design features, as a power basis for a hydrostatic transmission, with a limitation in power of application.

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Pobędza, Janusz, and Andrzej Sobczyk. "Modern Coating Used in High Pressure Water Hydraulic Components." Key Engineering Materials 542 (February 2013): 143–55. http://dx.doi.org/10.4028/www.scientific.net/kem.542.143.

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Water hydraulics is coming back as an alternative to oil and other not environment friendly working fluids used in very wide range of fluid drive and control systems. One of the barrier causing that water hydraulics is cost of water resistant materials for components, especially moving parts such as pump pistons, surface of cylinder tubes and rods, poppet and seats, etc. to avoid corrosion. One of common solution is to use stainless steel there, where it can cooperate with other nonmetallic material such as plastic or other noncorrosive metallic composite to reduce friction. Thus some of research were directed to elaboration of special coating for covering surfaces in critical regions of water hydraulic components. The article describe results of pilot research on selected components where such coating were introduced on regular carbon steel parts, same as used for oil hydraulics. First part of the article contents description of coating technology and some characteristics of coating layers. Second quotes selected results of conducted by authors research on coated hydraulic cylinders and poppet valves.

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Burlachenko, O. V., N. V. Fomenko, and A. A. Lyashenko. "Ground vehicles hydraulic system pneumatic hydraulic valve." IOP Conference Series: Materials Science and Engineering 709 (January 3, 2020): 033027. http://dx.doi.org/10.1088/1757-899x/709/3/033027.

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Journal articles on the topic 'Hydraulic'

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