Sample records for strength hydraulic head

  1. Integrated hydraulic cooler and return rail in camless cylinder head

    Marriott, Craig D [Clawson, MI; Neal, Timothy L [Ortonville, MI; Swain, Jeff L [Flushing, MI; Raimao, Miguel A [Colorado Springs, CO


    An engine assembly may include a cylinder head defining an engine coolant reservoir, a pressurized fluid supply, a valve actuation assembly, and a hydraulic fluid reservoir. The valve actuation assembly may be in fluid communication with the pressurized fluid supply and may include a valve member displaceable by a force applied by the pressurized fluid supply. The hydraulic fluid reservoir may be in fluid communication with the valve actuation assembly and in a heat exchange relation to the engine coolant reservoir.

  2. Averaging hydraulic head, pressure head, and gravitational head in subsurface hydrology, and implications for averaged fluxes, and hydraulic conductivity

    G. H. de Rooij


    Full Text Available Current theories for water flow in porous media are valid for scales much smaller than those at which problem of public interest manifest themselves. This provides a drive for upscaled flow equations with their associated upscaled parameters. Upscaling is often achieved through volume averaging, but the solution to the resulting closure problem imposes severe restrictions to the flow conditions that limit the practical applicability. Here, the derivation of a closed expression of the effective hydraulic conductivity is forfeited to circumvent the closure problem. Thus, more limited but practical results can be derived. At the Representative Elementary Volume scale and larger scales, the gravitational potential and fluid pressure are treated as additive potentials. The necessary requirement that the superposition be maintained across scales is combined with conservation of energy during volume integration to establish consistent upscaling equations for the various heads. The power of these upscaling equations is demonstrated by the derivation of upscaled water content-matric head relationships and the resolution of an apparent paradox reported in the literature that is shown to have arisen from a violation of the superposition principle. Applying the upscaling procedure to Darcy's Law leads to the general definition of an upscaled hydraulic conductivity. By examining this definition in detail for porous media with different degrees of heterogeneity, a series of criteria is derived that must be satisfied for Darcy's Law to remain valid at a larger scale.

  3. Determination of Material Strengths by Hydraulic Bulge Test

    Hankui Wang


    Full Text Available The hydraulic bulge test (HBT method is proposed to determine material tensile strengths. The basic idea of HBT is similar to the small punch test (SPT, but inspired by the manufacturing process of rupture discs—high-pressure hydraulic oil is used instead of punch to cause specimen deformation. Compared with SPT method, the HBT method can avoid some of influence factors, such as punch dimension, punch material, and the friction between punch and specimen. A calculation procedure that is entirely based on theoretical derivation is proposed for estimate yield strength and ultimate tensile strength. Both conventional tensile tests and hydraulic bulge tests were carried out for several ferrous alloys, and the results showed that hydraulic bulge test results are reliable and accurate.

  4. Determination of Material Strengths by Hydraulic Bulge Test.

    Wang, Hankui; Xu, Tong; Shou, Binan


    The hydraulic bulge test (HBT) method is proposed to determine material tensile strengths. The basic idea of HBT is similar to the small punch test (SPT), but inspired by the manufacturing process of rupture discs-high-pressure hydraulic oil is used instead of punch to cause specimen deformation. Compared with SPT method, the HBT method can avoid some of influence factors, such as punch dimension, punch material, and the friction between punch and specimen. A calculation procedure that is entirely based on theoretical derivation is proposed for estimate yield strength and ultimate tensile strength. Both conventional tensile tests and hydraulic bulge tests were carried out for several ferrous alloys, and the results showed that hydraulic bulge test results are reliable and accurate.

  5. Experimental Study For Pizometric Head Distribution Under Hydraulic Structures

    Dr. Najm Obaid Salim Alghazali


    Full Text Available Abstract In this research the experimental method by using Hydraulic modeling used to determination the flow net in order to analyses seepage flow through single- layer soil foundation underneath hydraulic structure. as well as steady the consequence of the cut-off inclination angle on exit gradient factor of safety uplift pressure and quantity of seepage by using seepage tank were designed in the laboratory with proper dimensions with two cutoffs . The physical model seepage tank was designed in two downstream cutoff angles which are 90 and 120 and upstream cutoff angles 90 45 120. After steady state flow the flow line is constructed by dye injection in the soil from the upstream side in front view of the seepage tank and the equipotentials line can be constructed by pizometer fixed to measure the total head. From the result It is concluded that using downstream cut-off inclined towards the downstream side with amp1256 equal 120 that given value of redaction 25 is beneficial in increasing the safety factor against the piping phenomenon. using upstream cut-off inclined towards the downstream side with amp1256 equal 45 that given value of redaction 52 is beneficial in decreasing uplift pressure and quantity of seepage.

  6. Design Formulae for Hydraulic Stability and Structural Integrity of Dolos Breakwater Round-Heads

    Burcharth, H. F.; Jensen, Jacob Birk; Liu, Z.


    A rational design of Dolos armour unit should incorporate both the hydraulic stability and the structural integrity. The previous tests performed by Aalborg University (AU) resulted in design formulae for the trunk of a 1:1.5 slope Dolos breakwater without superstructure including both...... the hydraulic stability and the structural integrity. The objective of the round-head tests is to produce similar design formulae for Dolos armour in around-head. The tests will also include examinations of the hydraulic stability and run-up for a trunk section adjacent to the round-head. A run-up formula...

  7. Neck strength imbalance correlates with increased head acceleration in soccer heading.

    Dezman, Zachary D W; Ledet, Eric H; Kerr, Hamish A


    Soccer heading is using the head to directly contact the ball, often to advance the ball down the field or score. It is a skill fundamental to the game, yet it has come under scrutiny. Repeated subclinical effects of heading may compound over time, resulting in neurologic deficits. Greater head accelerations are linked to brain injury. Developing an understanding of how the neck muscles help stabilize and reduce head acceleration during impact may help prevent brain injury. Neck strength imbalance correlates to increasing head acceleration during impact while heading a soccer ball. Observational laboratory investigation. Sixteen Division I and II collegiate soccer players headed a ball in a controlled indoor laboratory setting while player motions were recorded by a 14-camera Vicon MX motion capture system. Neck flexor and extensor strength of each player was measured using a spring-type clinical dynamometer. Players were served soccer balls by hand at a mean velocity of 4.29 m/s (±0.74 m/s). Players returned the ball to the server using a heading maneuver at a mean velocity of 5.48 m/s (±1.18 m/s). Mean neck strength difference was positively correlated with angular head acceleration (rho = 0.497; P = 0.05), with a trend toward significance for linear head acceleration (rho = 0.485; P = 0.057). This study suggests that symmetrical strength in neck flexors and extensors reduces head acceleration experienced during low-velocity heading in experienced collegiate players. Balanced neck strength may reduce head acceleration cumulative subclinical injury. Since neck strength is a measureable and amenable strength training intervention, this may represent a modifiable intrinsic risk factor for injury.

  8. Locations of hydraulic-head observations (HOBS) for the Central Valley Hydrologic Model (CVHM)

    U.S. Geological Survey, Department of the Interior — This digital dataset defines the well locations for hydraulic-head observations used in the calibration of the transient hydrologic model of the Central Valley flow...

  9. Vertical groundwater storage properties and changes in confinement determined using hydraulic head response to atmospheric tides

    Acworth, R. Ian; Rau, Gabriel C.; Halloran, Landon J. S.; Timms, Wendy A.


    Accurate determination of groundwater state of confinement and compressible storage properties at vertical resolution over depth is notoriously difficult. We use the hydraulic head response to atmospheric tides at 2 cpd frequency as a tracer to quantify barometric efficiency (BE) and specific storage (Ss) over depth. Records of synthesized Earth tides, atmospheric pressure, and hydraulic heads measured in nine piezometers completed at depths between 5 and 55 m into unconsolidated smectitic clay and silt, sand and gravel were examined in the frequency domain. The barometric efficiency increased over depth from ˜0.05 in silty clay to ˜0.15 in sands and gravels. BE for silty clay was confirmed by calculating the loading efficiency as 0.95 using rainfall at the surface. Specific storage was calculated using effective rather than total moisture. The differences in phase between atmospheric pressure and hydraulic heads at 2 cpd were ˜180° below 10 m indicating confined conditions despite the low BE. Heads in the sediment above a fine sand and silt layer at 12 m exhibited a time variable phase difference between 0° and 180° indicating varying confinement. Our results illustrate that the atmospheric tide at 2 cpd is a powerful natural tracer for quantifying groundwater state of confinement and compressible storage properties in layered formations from hydraulic heads and atmospheric pressure records without the need for externally induced hydraulic stress. This approach could significantly improve the development of conceptual hydrogeological model used for groundwater resource development and management.

  10. Effect of hydraulic head and slope on water distribution uniformity of the IDE drip irrigation system

    Ella, Victor B.; Reyes, Manuel R.; R. Yoder


    Assessment of the effect of topography and operating heads on the emission uniformity distribution in drip irrigation systems is important in water management and could serve as the basis for optimizing water-use efficiency and crop productivity. This study was carried out to evaluate the effect of slope and hydraulic head on the water distribution uniformity of a low-cost drip irrigation system developed by International Development Enterprises (IDE). The drip system was tested for water dis...

  11. Hydraulic slotting technology to prevent coal and gas outburst during heading excavation

    Wei, G.; Guo, Z.; Xie, L.; Xin, X.; Shan, Z. [Henan Polytechnic University, Jiaozuo (China)


    The technology of measures to prevent coal and gas outburst was analyzed in serious outburst coal seam under research and experiments in real situations. A new measure, called hydraulic slotting, was described and studied in detail. The characteristic parameters of hydraulic slotting was given in the Jiaozuo mining area and the characteristics of validity, adaptability and security were evaluated. The research results show that slotting heading by high pressure large diameter jet releases not only the stress surrounding the strata but also the gas in coal seam is revealed. The resistance to coal and gas outburst was increased dramatically at once if the area of the slot was big enough. The experimentation succeeded in a 2000 m heading excavation and prevented coal and gas outburst. The heading driving speed was more than doubled. 6 refs., 3 figs., 3 tabs.

  12. Hydraulics.

    Decker, Robert L.; Kirby, Klane

    This curriculum guide contains a course in hydraulics to train entry-level workers for automotive mechanics and other fields that utilize hydraulics. The module contains 14 instructional units that cover the following topics: (1) introduction to hydraulics; (2) fundamentals of hydraulics; (3) reservoirs; (4) lines, fittings, and couplers; (5)…

  13. Pinhole test for identifying susceptibility of soils to piping erosion: effect water quality and hydraulic head

    Nadal Romero, E.; Verachtert, E.; Poesen, J.


    Piping has been observed in both natural and soils, as well as under different types of land uses and vegetation covers. Despite its importance, no standard widely-applied methodology exists to assess susceptibility of soils to piping. This study aims at evaluating the pinhole test for assessing the susceptibility of soils to piping under different conditions. More precisely, the effects of hydraulic head and water quality are being assessed. Topsoil samples (remoulded specimens) with a small range of water contents were taken in Central Belgium (Heverlee) and the susceptibility of these soil samples are investigated under standardized laboratory conditions with a pinhole test device. Three hydraulic heads (50,180 and 380 mm) and two water qualities (tap and distilled water) were used, reflecting dominant field conditions. (Author) 6 refs.

  14. Spring 1961 hydraulic head in the lower pumped zone of California's Central Valley (from Williamson and others, 1989)

    U.S. Geological Survey, Department of the Interior — This digital dataset defines the spring 1961 hydraulic head in the lower pumped zone of California's Central Valley. It was used to initiate the water-level...

  15. Evaluation of compressive strength of hydraulic silicate-based root-end filling materials.

    Walsh, Ryan M; Woodmansey, Karl F; Glickman, Gerald N; He, Jianing


    Hydraulic silicate cements such as mineral trioxide aggregate (MTA) have many clinical advantages. Newer hydraulic silicate materials have been developed that improve on the limitations of mineral trioxide aggregate such as the long setting time and difficult handling characteristics. The purpose of this study was to examine the effect of saline and fetal bovine serum (FBS) on the setting and compressive strength of the following hydraulic silicate cements: ProRoot MTA (white WMTA; Dentsply International, Tulsa Dental Specialties, Johnson City, TN), EndoSequence Root Repair Material (Brasseler USA, Savannah, GA), MTA Plus (MTAP; Avalon Biomed Inc, Bradenton, FL), and QuickSet (QS; Avalon Biomed Inc, Bradenton, FL). Samples of root-end filling materials were compacted into polyethylene molds. Samples were exposed to FBS or saline for 7 days. A universal testing machine was used to determine the compressive strengths. QS had significantly lower compressive strength than all other materials (P materials, other than QS, have compressive strength similar to MTA. Within the limits of this study, premixed materials and those mixed with antiwashout gel maintain their compressive strength when exposed to biological fluids. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Joint inversion of hydraulic head and self-potential data associated with harmonic pumping tests

    Soueid Ahmed, A.; Jardani, A.; Revil, A.; Dupont, J. P.


    Harmonic pumping tests consist in stimulating an aquifer by the means of hydraulic stimulations at some discrete frequencies. The inverse problem consisting in retrieving the hydraulic properties is inherently ill posed and is usually underdetermined when considering the number of well head data available in field conditions. To better constrain this inverse problem, we add self-potential data recorded at the ground surface to the head data. The self-potential method is a passive geophysical method. Its signals are generated by the groundwater flow through an electrokinetic coupling. We showed using a 3-D saturated unconfined synthetic aquifer that the self-potential method significantly improves the results of the harmonic hydraulic tomography. The hydroelectric forward problem is obtained by solving first the Richards equation, describing the groundwater flow, and then using the result in an electrical Poisson equation describing the self-potential problem. The joint inversion problem is solved using a reduction model based on the principal component geostatistical approach. In this method, the large prior covariance matrix is truncated and replaced by its low-rank approximation, allowing thus for notable computational time and storage savings. Three test cases are studied, to assess the validity of our approach. In the first test, we show that when the number of harmonic stimulations is low, combining the harmonic hydraulic and self-potential data does not improve the inversion results. In the second test where enough harmonic stimulations are performed, a significant improvement of the hydraulic parameters is observed. In the last synthetic test, we show that the electrical conductivity field required to invert the self-potential data can be determined with enough accuracy using an electrical resistivity tomography survey using the same electrodes configuration as used for the self-potential investigation.

  17. The strength/moisture relations and hydraulic conductivity of Mexican tepetate

    Nimlos, T.J. (Univ. of Montana, Missoula (USA)); Hillery P.A. (Environmental Information Center, Helena, MT (USA))


    Indurated soil material formed from volcanic-ash-flow tuff is widespread in the Pacific rim portions of Latin America. This material is called tepetate in Mexico where, in some areas, all soil overlying tepetate has been removed by erosion, leaving a barren landscape with a very slowly permeable surface that contributes to overland flow and flooding. Reclamation of this land involves ripping to break up the upper part of the tepetate or terracing to retain water so that it may infiltrate. Tepetate strength and hydraulic conductivity influence both treatments. The authors determined the change in tepetate strength with moisture. Unconfined compressive strength of eight typical samples was measured at four moisture contents. Strength declined with increasing moisture, especially in samples of high or moderate strength. These data suggest that tepetate of moderate or high strength should be reclaimed during the wet season, whereas low-strength tepetate can be reclaimed at any season. They also determined tepetate's saturated hydraulic conductivity; it varied from 1.5 {times} 10{sup {minus}7} to 36.0 {times} 10{sup {minus}7} m/s. These low values demonstrate the very slowly permeable nature of tepetate and account for the extensive erosion and flooding frequency.

  18. Straight-flow hydraulic turbine-generator for ultralow-head

    Kushimoto, Masakazu; Ujiie, Ryuichi (Fuji Electric Co., Ltd., Tokyo (Japan))


    This report introduces features and structures of the straight-flow hydraulic turbine-generator considered for ultralow-head hydropower generation. Largest feature of straight flow(S/F) is that the generator rotor is fitted so as to surround the periphery of runner. This fundamental structure is classified to overhang type, downstream stay-column type and others dependent on the arrangement of main bearing which supports the rotor weight. The essential part of the hydraulic turbine is the sealing equipment for the center part of the rotor. Special attention must be paid to the selection of material and structure of this equipment. The maximum point to determine the structure is the countermeasure for the radial and axial rigidity reduction in the S/F hydro-generator. It is also necessary to conduct moisture prevention for the generator and to insulate to prevent axial current. 13 refs., 6 figs.

  19. A new zonation algorithm with parameter estimation using hydraulic head and subsidence observations.

    Zhang, Meijing; Burbey, Thomas J; Nunes, Vitor Dos Santos; Borggaard, Jeff


    Parameter estimation codes such as UCODE_2005 are becoming well-known tools in groundwater modeling investigations. These programs estimate important parameter values such as transmissivity (T) and aquifer storage values (Sa ) from known observations of hydraulic head, flow, or other physical quantities. One drawback inherent in these codes is that the parameter zones must be specified by the user. However, such knowledge is often unknown even if a detailed hydrogeological description is available. To overcome this deficiency, we present a discrete adjoint algorithm for identifying suitable zonations from hydraulic head and subsidence measurements, which are highly sensitive to both elastic (Sske) and inelastic (Sskv) skeletal specific storage coefficients. With the advent of interferometric synthetic aperture radar (InSAR), distributed spatial and temporal subsidence measurements can be obtained. A synthetic conceptual model containing seven transmissivity zones, one aquifer storage zone and three interbed zones for elastic and inelastic storage coefficients were developed to simulate drawdown and subsidence in an aquifer interbedded with clay that exhibits delayed drainage. Simulated delayed land subsidence and groundwater head data are assumed to be the observed measurements, to which the discrete adjoint algorithm is called to create approximate spatial zonations of T, Sske , and Sskv . UCODE-2005 is then used to obtain the final optimal parameter values. Calibration results indicate that the estimated zonations calculated from the discrete adjoint algorithm closely approximate the true parameter zonations. This automation algorithm reduces the bias established by the initial distribution of zones and provides a robust parameter zonation distribution.

  20. Protective coating as a factor to ensure the strength and hydraulic performance of recoverable pipelines

    Orlov Vladimir Aleksandrovich; Zotkin Sergey Petrovich; Khrenov Konstantin Evgen’evich; Dezhina Irina Sergeevna; Bogomolova Irina Olegovna


    The authors present an analysis of various types of internal protective pipeline coatings to ensure the strength and hydraulic characteristics of a remodeled pipeline and related coating methods for effective trenchless renovation of engineering systems, water supply systems and sanitation. As protective coating the authors considered a round profile tube of a smaller diameter than of the old pipe, close to the old pipe, sprayed lining on the basis of inorganic and inorganic materials. The ar...

  1. Using environmental tracers and transient hydraulic heads to estimate groundwater recharge and conductivity

    Erdal, Daniel; Cirpka, Olaf A.


    Regional groundwater flow strongly depends on groundwater recharge and hydraulic conductivity. While conductivity is a spatially variable field, recharge can vary in both space and time. None of the two fields can be reliably observed on larger scales, and their estimation from other sparse data sets is an open topic. Further, common hydraulic-head observations may not suffice to constrain both fields simultaneously. In the current work we use the Ensemble Kalman filter to estimate spatially variable conductivity, spatiotemporally variable recharge and porosity for a synthetic phreatic aquifer. We use transient hydraulic-head and one spatially distributed set of environmental tracer observations to constrain the estimation. As environmental tracers generally reside for a long time in an aquifer, they require long simulation times and carries a long memory that makes them highly unsuitable for use in a sequential framework. Therefore, in this work we use the environmental tracer information to precondition the initial ensemble of recharge and conductivities, before starting the sequential filter. Thereby, we aim at improving the performance of the sequential filter by limiting the range of the recharge to values similar to the long-term annual recharge means and by creating an initial ensemble of conductivities that show similar pattern and values to the true field. The sequential filter is then used to further improve the parameters and to estimate the short term temporal behavior as well as the temporally evolving head field needed for short term predictions within the aquifer. For a virtual reality covering a subsection of the river Neckar it is shown that the use of environmental tracers can improve the performance of the filter. Results using the EnKF with and without this preconditioned initial ensemble are evaluated and discussed.

  2. Impact of uncertainty description on assimilating hydraulic head in the MIKE SHE distributed hydrological model

    Zhang, Donghua; Madsen, Henrik; Ridler, Marc E.


    uncertainty. In most hydrological EnKF applications, an ad hoc model uncertainty is defined with the aim of avoiding a collapse of the filter. The present work provides a systematic assessment of model uncertainty in DA applications based on combinations of forcing, model parameters, and state uncertainties....... This is tested in a case where groundwater hydraulic heads are assimilated into a distributed and integrated catchment-scale model of the Karup catchment in Denmark. A series of synthetic data assimilation experiments are carried out to analyse the impact of different model uncertainty assumptions...

  3. Modeling and experiments on the drive characteristics of high-strength water hydraulic artificial muscles

    Zhang, Zengmeng; Hou, Jiaoyi; Ning, Dayong; Gong, Xiaofeng; Gong, Yongjun


    Fluidic artificial muscles are popular in robotics and function as biomimetic actuators. Their pneumatic version has been widely investigated. A novel water hydraulic artificial muscle (WHAM) with high strength is developed in this study. WHAMs can be applied to underwater manipulators widely used in ocean development because of their environment-friendly characteristics, high force-to-weight ratio, and good bio-imitability. Therefore, the strength of WHAMs has been improved to fit the requirements of underwater environments and the work pressure of water hydraulic components. However, understanding the mechanical behaviors of WHAMs is necessary because WHAMs use work media and pressure control that are different from those used by pneumatic artificial muscles. This paper presents the static and dynamic characteristics of the WHAM system, including the water hydraulic pressure control circuit. A test system is designed and built to analyze the drive characteristics of the developed WHAM. The theoretical relationships among the amount of contraction, pressure, and output drawing force of the WHAM are tested and verified. A linearized transfer function is proposed, and the dynamic characteristics of the WHAM are investigated through simulation and inertia load experiments. Simulation results agree with the experimental results and show that the proposed model can be applied to the control of WHAM actuators.

  4. Numerical analysis of Coriolis effect on low-head hydraulic turbines

    Ahn, S. H.; Xiao, Y. X.; Zhou, X. Z.; Zhang, J.; Zeng, C. J.; Luo, Y. Y.; Xu, W.; Wang, Z. W.


    For the low-head hydropower station, the operating head is low, and the turbine intake channel is relatively short. The turbine internal flow behaviour can be influenced by fluid flows in the upstream reservoir easily, then it would influence the turbine hydraulic performance. Water flows in the upstream reservoir can be influenced by the Coriolis force by the Earth rotation, and it differs at the different Rossby number. In this paper, the Coriolis effect on the approach flows and the turbine performances are investigated numerically for the low-head units. Firstly, the Coriolis effect (under the different latitudes and the same characteristic length scale) on reservoir flows was predicted. Secondly, the prototype performance of a bulb-type turbine was simulated including the reservoir flow with the Coriolis effect, and then the effect on the turbine performance is be discussed. Results show that the flow field in the upstream reservoir at the low Rossby number, the ratio of inertial force to Coriolis force, can sufficiently influence the turbine intake flows and the turbine performances. Adjusting the side-wall distance can reduce the Coriolis effects.

  5. Success in the Classroom and in Life: Focusing on Strengths of the Head "and" Strengths of the Heart

    Pfeiffer, Steven I.


    "Strengths of the heart" is a new and potentially useful paradigm for understanding how the "whole" gifted child can thrive and flourish. Until recently, those who have written about and have researched the gifted have focused much of their work on "strengths of the head"--understanding, identifying, and promoting…

  6. Effect of hydraulic head and slope on water distribution uniformity of a low-cost drip irrigation system

    Ella, Victor B.; Reyes, Manuel R.; R. Yoder


    Metadata only record Assessment of the effect of topography and operating heads on the emission uniformity distribution in drip irrigation systems is important in irrigation water management and could serve as basis for optimizing water use efficiency and crop productivity. This study was carried out to evaluate the effect of hydraulic head and slope on the water distribution uniformity of a low-cost drip irrigation system developed by the International Development Enterprises (IDE), a non...

  7. Temporal and vertical variation of hydraulic head in aquifers in the Edgewood area, Aberdeen Proving Ground, Maryland

    Donnelly, Colleen A.; Tenbus, Fredrick J.


    Water-level data and interpretations from previous hydrogeological studies conducted by the U.S. Geological Survey in the Edgewood Area of Aberdeen Proving Ground (APG), Maryland, were compared to determine similarities and differences among the aquifers. Because the sediments that comprise the shallow aquifers are discontinuous, the shallow ground-water-flow systems are local rather than extensive across the Edgewood Area. Hydrogeologic cross sections, hydrographs of water levels, and vertical gradients calculated from previous studies in the Canal Creek area, Graces Quarters, the O-Field area, Carroll Island, and the J-Field area, over periods of record ranging from 1 to 10 years during 1986-97, were used to determine recharge and discharge areas, connections between aquifers, and hydrologic responses of aquifers to natural and anthropogenic stress. Each of the aquifers in the study areas exhibited variation of hydraulic head that was attributed to seasonal changes in recharge. Upward hydraulic gradients and seasonal reversals of vertical hydraulic gradients between aquifers indicate the potential for local ground-water discharge from most of the aquifers that were studied in the Edgewood Area. Hydraulic head in individual aquifers in Graces Quarters and Carroll Island responded to offsite pumping during part of the period of record. Hydraulic head in most of the confined aquifers responded to tidal loading effects from nearby estuaries.

  8. The Maintenance of Heading Machine Hydraulic System%掘进机液压系统的维护



    The paper mainly discussed the rotation of hydraulic tank, oil return filter system and the axial piston pump of heading machine's hydraulic system, the adjustment of axial piston pump, relief valve pressure and one-way throttle valve and the maintenance of hydraulic system and the using of hydraulic components.%本文主要阐述了掘进机液压系统的液压油箱、液压系统的回油过滤器、轴向柱塞泵的旋转、轴向柱塞泵、溢流阀压力的调整、单向节流阀的调整、液压系统维护、液压元件的使用等维护.

  9. Transient flow between aquifers and surface water: analytically derived field-scale hydraulic heads and fluxes

    G. H. de Rooij


    Full Text Available The increasing importance of catchment-scale and basin-scale models of the hydrological cycle makes it desirable to have a simple, yet physically realistic model for lateral subsurface water flow. As a first building block towards such a model, analytical solutions are presented for horizontal groundwater flow to surface waters held at prescribed water levels for aquifers with parallel and radial flow. The solutions are valid for a wide array of initial and boundary conditions and additions or withdrawals of water, and can handle discharge into as well as lateral infiltration from the surface water. Expressions for the average hydraulic head, the flux to or from the surface water, and the aquifer-scale hydraulic conductivity are developed to provide output at the scale of the modelled system rather than just point-scale values. The upscaled conductivity is time-variant. It does not depend on the magnitude of the flux but is determined by medium properties as well as the external forcings that drive the flow. For the systems studied, with lateral travel distances not exceeding 10 m, the circular aquifers respond very differently from the infinite-strip aquifers. The modelled fluxes are sensitive to the magnitude of the storage coefficient. For phreatic aquifers a value of 0.2 is argued to be representative, but considerable variations are likely. The effect of varying distributions over the day of recharge damps out rapidly; a soil water model that can provide accurate daily totals is preferable over a less accurate model hat correctly estimates the timing of recharge peaks.

  10. Impact of uncertainty description on assimilating hydraulic head in the MIKE SHE distributed hydrological model

    Zhang, Donghua; Madsen, Henrik; Ridler, Marc E.; Refsgaard, Jens C.; Jensen, Karsten H.


    The ensemble Kalman filter (EnKF) is a popular data assimilation (DA) technique that has been extensively used in environmental sciences for combining complementary information from model predictions and observations. One of the major challenges in EnKF applications is the description of model uncertainty. In most hydrological EnKF applications, an ad hoc model uncertainty is defined with the aim of avoiding a collapse of the filter. The present work provides a systematic assessment of model uncertainty in DA applications based on combinations of forcing, model parameters, and state uncertainties. This is tested in a case where groundwater hydraulic heads are assimilated into a distributed and integrated catchment-scale model of the Karup catchment in Denmark. A series of synthetic data assimilation experiments are carried out to analyse the impact of different model uncertainty assumptions on the feasibility and efficiency of the assimilation. The synthetic data used in the assimilation study makes it possible to diagnose model uncertainty assumptions statistically. Besides the model uncertainty, other factors such as observation error, observation locations, and ensemble size are also analysed with respect to performance and sensitivity. Results show that inappropriate definition of model uncertainty can greatly degrade the assimilation performance, and an appropriate combination of different model uncertainty sources is advised.

  11. Temporal response of hydraulic head, temperature, and chloride concentrations to sea-level changes, Floridan aquifer system, USA

    Hughes, J. D.; Vacher, H. L.; Sanford, Ward E.


    Three-dimensional density-dependent flow and transport modeling of the Floridan aquifer system, USA shows that current chloride concentrations are not in equilibrium with current sea level and, second, that the geometric configuration of the aquifer has a significant effect on system responses. The modeling shows that hydraulic head equilibrates first, followed by temperatures, and then by chloride concentrations. The model was constructed using a modified version of SUTRA capable of simulating multi-species heat and solute transport, and was compared to pre-development conditions using hydraulic heads, chloride concentrations, and temperatures from 315 observation wells. Three hypothetical, sinusoidal sea-level changes occurring over 100,000 years were used to evaluate how the simulated aquifer responds to sea-level changes. Model results show that hydraulic head responses lag behind sea-level changes only where the Miocene Hawthorn confining unit is thick and represents a significant restriction to flow. Temperatures equilibrate quickly except where the Hawthorn confining unit is thick and the duration of the sea-level event is long (exceeding 30,000 years). Response times for chloride concentrations to equilibrate are shortest near the coastline and where the aquifer is unconfined; in contrast, chloride concentrations do not change significantly over the 100,000-year simulation period where the Hawthorn confining unit is thick.

  12. Locations, values, and uncertainties of hydraulic-head observations for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    U.S. Geological Survey, Department of the Interior — This digital geospatial data set contains the locations, values, and uncertainties of hydraulic-head observations used in the calibration of the transient model of...

  13. Data tables of well locations, perforated intervals, and time series of hydraulic-head observations for the Central Valley Hydrologic Model (CVHM)

    U.S. Geological Survey, Department of the Interior — This digital dataset defines the well locations, perforated intervals, and time series of hydraulic-head observations used in the calibration of the transient...

  14. Initial hydraulic heads for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    U.S. Geological Survey, Department of the Interior — This digital data set defines the hydraulic-head values in 16 model layers used to initiate the transient simulation of the Death Valley regional ground-water flow...

  15. Locations, values, and uncertainties of hydraulic-head observations for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    U.S. Geological Survey, Department of the Interior — This digital geospatial data set contains the locations, values, and uncertainties of hydraulic-head observations used in the calibration of the transient model of...

  16. The Use of Hydraulic Head and Atmospheric Tritium to Identify Presence of Fractures in Clayey Aquitards: Numerical Analysis

    Farah, E. A.; Parker, B. L.; Cherry, J. A.


    Surficial clayey aquitards can provide underlying aquifers with strong protection from contamination if vertically connected open fractures are absent. Hence, methods are needed to identify such contaminant pathways. An existing two-dimensional model for steady-state groundwater flow and solute transport (FRACTRAN) was used for cross-sectional simulations to assess the prospects for using field measurements of hydraulic head and atmospheric (i.e. bomb) tritium in surficial aquitards to determine presence and nature of hydraulically connected fractures. Simulations for a 15-m thick horizontal aquitard, with shallow water table and downward groundwater flow, show that field measurements of head and tritium at points appropriately spaced along a horizontal line at the lower part of the aquitard provide unique insight since they offer the highest chance for detecting vertical fractures. Simulations represented sets of predominant vertical and horizontal fractures of uniform aperture (25 æm) and variable length. The simulations focused on fracture-network features assigned based on the literature of field investigations. The horizontal profiles show peaks and troughs for head, and always peaks for tritium concentrations at fracture localities. Use of only head or tritium alone may locate fractures, but may not discover whether each fracture is connected to the ground surface or aquifer top, or both. On the other hand, the coupled patterns of head and tritium can be used to identify fractures more accurately. For example, a head trough and a tritium sharp peak represent a fully penetrating fracture, while a head peak and a rounded-tip tritium peak represent a partially penetrating fracture. Moreover, these two are easily differentiated from an embedded fracture that is represented by a relatively small head trough and a short sharp tritium peak. The method of monitoring along a horizontal line was applied to the conceptual 15-m thick aquitard imitating horizontal

  17. The relationship between impact force, neck strength, and neurocognitive performance in soccer heading in adolescent females.

    Gutierrez, Gregory M; Conte, Catherine; Lightbourne, Kristian


    Head impacts are common in contact sports, but only recently has there been a rising awareness of the effects of subconcussive impacts in adolescent athletes. A better understanding of how to attenuate head impacts is needed and therefore, this study investigated the relationship between neck strength, impact, and neurocognitive function in an acute bout of soccer heading in a sample of female high school varsity soccer players. Seventeen participants completed the ImPACT neurocognitive test and had their isometric neck strength tested (flexion, extension, and bilateral flexion) before heading drills. Each participant was outfitted with custom headgear with timing switches and a three-dimensional accelerometer affixed to the back of the head, which allowed for measurement of impact during heading. Participants performed a series of 15 directional headers, including 5 forward, 5 left and 5 right headers in a random order, then completed the ImPACT test again. Neurocognitive tests revealed no significant changes following heading. However, there were statistically significant, moderate, negative correlations (r = -0.500:-0.757, p head injury prevention/reduction program.

  18. An Analytical Solution of Hydraulic Head due to an Oscillatory Pumping Test in a Confined, Unconfined or Leaky Aquifer

    Huang, C. S.; Yeh, H. D.


    This study builds a mathematical model for three-dimensional (3D) transient hydraulic head induced by an oscillatory pumping test in a confined, unconfined or leaky aquifer. The aquifers are of a rectangular shape where the four sides are under the Robin conditions. The 3D flow governing equation with a line sink term representing a vertical well is employed. The sink term has a cosine function for the oscillatory pumping. A general equation describing the head on the top of the three kinds of aquifers is considered. The analytical head solution of the model is derived by the direct Fourier method and the double-integral transform and in terms of a double series with fast convergence. With the aid of the solution, we have found that the vertical component of flow vanishes when Kv d2/(KhD2) > 1 where Kh and Kv are aquifer's hydraulic conductivities, respectively, D is aquifer's thickness, and d is a distance measured from the pumping well. Under the condition, temporal head distributions predicted by the present solution agree with those predicted by solutions developed based on two-dimensional flow by most previous researches.

  19. Protective coating as a factor to ensure the strength and hydraulic performance of recoverable pipelines

    Orlov Vladimir Aleksandrovich


    Full Text Available The authors present an analysis of various types of internal protective pipeline coatings to ensure the strength and hydraulic characteristics of a remodeled pipeline and related coating methods for effective trenchless renovation of engineering systems, water supply systems and sanitation. As protective coating the authors considered a round profile tube of a smaller diameter than of the old pipe, close to the old pipe, sprayed lining on the basis of inorganic and inorganic materials. The article analyzes the methods of trenchless renovation for applying protective coatings: routing in the old pipeline of new pipes made of polymeric materials or polymeric sleeves, centrifugal spraying on the inner surface of pipelines’ inorganic and organic protective coatings. Special attention was paid to bag technology, providing the required strength properties at specific values of the modulus of elasticity and a number of external factors such as the depth of the existing pipe, the existence and magnitude of the horizon groundwater over it. Also attention is paid to the application technology of tape coatings ribbed profile on the inner surface of pipelines. This technology has a unique feature, which is the ability of recoverable pipeline functioning during its renovation by winding an endless belt and the formation of a new pipe. The tape coating winding is carried out by different types of spiral winding machines. The thickness of the protective coating layer forming the tube remains minimal. Inorganic cement-sand and organic coatings were considered as alternative options for repair of pipelines, which allow to localize the defects in the form of a fistula, minor cracks and other damages. However it is noted that a cement-sandy covering is inferior to organic, because it does not provide the strength characteristics of the pipeline system. The main advantage of the organic coating is mudding fistula of a large diameter, making a high wear

  20. Simultaneous transient operation of a high head hydro power plant and a storage pumping station in the same hydraulic scheme

    Bucur, D. M.; Dunca, G.; Cervantes, M. J.; Cǎlinoiu, C.; Isbǎşoiu, E. C.


    This paper presents an on-site experimental analysis of a high head hydro power plant and a storage pumping station, in an interconnected complex hydraulic scheme during simultaneous transient operation. The investigated hydropower site has a unique structure as the pumping station discharges the water into the hydropower plant penstock. The operation regimes were chosen for critical scenarios such as sudden load rejections of the turbines as well as start-ups and stops with different combinations of the hydraulic turbines and pumps operation. Several parameters were simultaneously measured such as the pumped water discharge, the pressure at the inlet pump section, at the outlet of the pumps and at the vane house of the hydraulic power plant surge tank. The results showed the dependence of the turbines and the pumps operation. Simultaneous operation of the turbines and the pumps is possible in safe conditions, without endangering the machines or the structures. Furthermore, simultaneous operation of the pumping station together with the hydropower plant increases the overall hydraulic efficiency of the site since shortening the discharge circuit of the pumps.

  1. Modelling and assessment of the electric field strength caused by mobile phone to the human head

    Buckus Raimondas


    Full Text Available Background/Aim. Electromagnetic field exposure is the one of the most important physical agents that actively affects live organisms and environment. Active use of mobile phones influences the increase of electromagnetic field radiation. The aim of the study was to measure and assess the electric field strength caused by mobile phones to the human head. Methods. In this paper the software “COMSOL Multiphysics” was used to establish the electric field strength created by mobile phones around the head. Results. The second generation (2G Global System for Mobile (GSM phones that operate in the frequency band of 900 MHz and reach the power of 2 W have a stronger electric field than (2G GSM mobile phones that operate in the higher frequency band of 1,800 MHz and reach the power up to 1 W during conversation. The third generation of (3G UMTS smart phones that effectively use high (2,100 MHz radio frequency band emit the smallest electric field strength values during conversation. The highest electric field strength created by mobile phones is around the ear, i.e. the mobile phone location. The strength of mobile phone electric field on the phantom head decreases exponentially while moving sidewards from the center of the effect zone (the ear, and constitutes 1-12% of the artificial head’s surface. Conclusion. The highest electric field strength values of mobile phones are associated with their higher power, bigger specific energy absorption rate (SAR and lower frequency of mobile phone. The stronger electric field emitted by the more powerful mobile phones takes a higher percentage of the head surface. The highest electric field strength created by mobile phones is distributed over the user ear.

  2. Influence of various types of damage on the fracture strength of ceramic femoral heads.

    Wuttke, Viola; Witte, Hartmut; Kempf, Katrin; Oberbach, Thomas; Delfosse, Daniel


    Ceramic-on-ceramic articulations are a frequently used bearing for total hip replacements. This success mainly is due to their excellent tribological properties. Ceramics can withstand high pressure loads due to its brittleness but only low bending stresses. A ceramic ball head fracture is the result of subcritical crack growth. This kind of fracture in vivo can abet by damage or contamination of the stem cone. The main goal of this work is to provide a risk assessment of different possible damage mechanisms and contaminations that may result in lower fracture strength of a ceramic ball head. To simulate potential causes, different types and dimensions of metal wire, foils, hair, and lubricants were inserted between the ceramic ball head and the metal cone of the stem. The test results clearly show that fracture strength is negatively influenced by most of the inhomogeneities between the cone and the head because they increase the peak stresses acting on a part of the ceramic ball head. The results of this article clearly confirm the demand for an undamaged taper fit "free of contamination" between the ceramic head and the metal cone during implantation.

  3. Test-retest reliability of handgrip strength measurement using a hydraulic hand dynamometer in patients with cervical radiculopathy.

    Savva, Christos; Giakas, Giannis; Efstathiou, Michalis; Karagiannis, Christos


    The purpose of this study was to evaluate the test-retest reliability of handgrip strength measurement using a hydraulic hand dynamometer in patients with cervical radiculopathy (CR). A convenience sample of 19 participants (14 men and 5 women; mean ± SD age, 50.5 ± 12 years) with CR was measured using a Jamar hydraulic hand dynamometer by the same rater on 2 different testing sessions with an interval of 7 days between sessions. Data collection procedures followed standardized grip strength testing guidelines established by the American Society of Hand Therapists. During the repeated measures, patients were advised to rest their upper limb in the standardized arm position and encouraged to exert 3 maximum gripping efforts. The mean value of the 3 efforts (measured in kilogram force [Kgf]) was used for data analysis. The intraclass correlation coefficient, SEM, and the Bland-Altman plot were used to estimate test-retest reliability and measurement precision. Grip strength measurement in CR demonstrated an intraclass correlation coefficient of 0.976, suggesting excellent test-retest reliability. The small SEM in both testing sessions (SEM1, 2.41 Kgf; SEM2, 2.51 Kgf) as well as the narrow width of the 95% limits of agreements (95% limits of agreement, -4.9 to 4.4 Kgf) in the Bland-Altman plot reflected precise measurements of grip strength in both occasions. Excellent test-retest reliability for grip strength measurement was measured in patients with CR, demonstrating that a hydraulic hand dynamometer could be used as an outcome measure for these patients. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  4. Flow of variable-density formation water in deep sloping aquifers: minimizing the error in representation and analysis when using hydraulic-head distributions

    Bachu, Stefan; Michael, Karsten


    Although not fully adequate, freshwater hydraulic heads have been used historically to represent and analyze variable-density flow in sloping aquifers in sedimentary basins. The use of environmental heads is valid only for strictly vertical flow in unconfined aquifers, while using variable-density hydraulic heads contravenes Darcy's law. Although the use of hydraulic-head surfaces is the simplest and quickest means of flow analysis and interpretation, preceding other methods such as numerical modeling, it introduces some errors that should be assessed and minimized in order to provide the most accurate flow representation. A first error is introduced when approximating the potential and buoyancy components along aquifer slope of the flow-driving force with their projections onto the horizontal plane. This error is most probably negligibly small for sloping aquifers in undisturbed sedimentary basins, but may be significant for aquifers dipping at a significant angle, such as in folded strata. A second error is introduced when using only hydraulic heads in the representation and analysis, and neglecting the buoyancy component of the flow-driving force. The significance of this error can be assessed by performing a Driving Force Ratio (DFR) analysis. There is no single or critical value of the DFR, below which the error in using hydraulic heads alone is negligible, and above which it is not acceptable anymore; rather, the decision regarding the error acceptability should and can be made on a case by case basis. The DFR, hence the errors in flow direction and magnitude, can be minimized for any given aquifer by using an optimum reference density in hydraulic-head calculations that is the areally-weighted average density of formation water in that aquifer. In flow analyses based on potentiometric surfaces, the use of freshwater as the reference density actually maximizes the errors introduced by the neglect of the buoyancy component of the flow-driving force because it

  5. Hydraulic characteristics of converse curvature section and aerator in high-head and large discharge spillway tunnel


    The hydraulic characteristics and cavitation erosion near the converse curvature section in the high-head and large discharge spillway tunnel have been important issues of concern to the hydropower project.In this paper,the evolutions of hydraulic elements such as pressure,flow velocity,wall shear stress, the converse curvature section are analyzed and the impacts of bottom aerator on hydraulic characteristics are discussed,with the commercial software FLUENT6.3 as a platform and combining the k-model and VOF method.The flow pattern in the converse curvature section of spillway tunnel is given by the three-dimensional numerical simulation.It indicates that the pressure changes rapidly with great pressure gradient from the beginning to the end of the curve.It also shows that the shear stress on side wall just downstream the end of the converse curvature curve is still increasing;the aeration cavity formed downstream the bottom aerator may cause the side wall pressure decreased to worsen the cavitation characteristics near the side wall.By means of the physical model experiment,the three-dimensional aerator composed of side wall baffling aerator and bottom aerator is studied,the baffling aerator suitable for the water flow conditions with water depth of 6.0 to 8.0 m and flow velocity of 35 to 50 m/s is proposed.

  6. Empirical analysis of the stress-strain relationship between hydraulic head and subsidence in the San Joaquin Valley Aquifer

    Neff, K. L.; Farr, T.


    Aquifer subsidence due to groundwater abstraction poses a significant threat to aquifer sustainability and infrastructure. The need to prevent permanent compaction to preserve aquifer storage capacity and protect infrastructure begs a better understanding of how compaction is related to groundwater abstraction and aquifer hydrogeology. The stress-strain relationship between hydraulic head changes and aquifer compaction has previously been observed to be hysteretic in both empirical and modeling studies. Here, subsidence data for central California's San Joaquin Valley derived from interferometric synthetic aperture radar (InSAR) for the period 2007-2016 is examined relative to hydraulic head levels in monitoring and production wells collected by the California Department of Water Resources. Such a large and long-term data set is available for empirical analysis for the first time thanks to advances in InSAR data collection and geospatial data management. The California Department of Water Resources (DWR) funded this work to provide the background and an update on subsidence in the Central Valley to support future policy. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.

  7. Characterisation of hydraulic head changes and aquifer properties in the London Basin using Persistent Scatterer Interferometry ground motion data

    Bonì, R.; Cigna, F.; Bricker, S.; Meisina, C.; McCormack, H.


    In this paper, Persistent Scatterer Interferometry was applied to ERS-1/2 and ENVISAT satellite data covering 1992-2000 and 2002-2010 respectively, to analyse the relationship between ground motion and hydraulic head changes in the London Basin, United Kingdom. The integration of observed groundwater levels provided by the Environment Agency and satellite-derived displacement time series allowed the estimation of the spatio-temporal variations of the Chalk aquifer storage coefficient and compressibility over an area of ∼1360 km2. The average storage coefficient of the aquifer reaches values of 1 × 10-3 and the estimated average aquifer compressibility is 7.7 × 10-10 Pa-1 and 1.2 × 10-9 Pa-1 for the periods 1992-2000 and 2002-2010, respectively. Derived storage coefficient values appear to be correlated with the hydrogeological setting, where confined by the London Clay the storage coefficient is typically an order of magnitude lower than where the chalk is overlain by the Lambeth Group. PSI-derived storage coefficient estimates agree with the values obtained from pumping tests in the same area. A simplified one-dimensional model is applied to simulate the ground motion response to hydraulic heads changes at nine piezometers. The comparison between simulated and satellite-observed ground motion changes reveals good agreement, with errors ranging between 1.4 and 6.9 mm, and being 3.2 mm on average.

  8. Design Formulae for Hydraulic Stability and Structural Integrity of Dolos Breakwater Round-Heads

    Burcharth, H. F.; Jensen, Jacob Birk; Liu, Z.


    A rational design of Dolos armour unit should incorporate both the hydraulic stability and the structural integrity. The previous tests performed by Aalborg University (AU) resulted in design formulae for the trunk of a 1:1.5 slope Dolos breakwater without superstructure including both...

  9. Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones

    Doughty, Christine; Tsang, Chin-Fu; Rosberg, Jan-Erik; Juhlin, Christopher; Dobson, Patrick F.; Birkholzer, Jens T.


    Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

  10. Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones

    Doughty, Christine; Tsang, Chin-Fu; Rosberg, Jan-Erik; Juhlin, Christopher; Dobson, Patrick F.; Birkholzer, Jens T.


    Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

  11. Multilevel groundwater monitoring of hydraulic head and temperature in the eastern Snake River Plain aquifer, Idaho National Laboratory, Idaho, 2007-08

    Fisher, Jason C.; Twining, Brian V.


    During 2007 and 2008, the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, collected quarterly depth-discrete measurements of fluid pressure and temperature in six boreholes located in the eastern Snake River Plain aquifer of Idaho. Each borehole was instrumented with a multilevel monitoring system consisting of a series of valved measurement ports, packer bladders, casing segments, and couplers. Hydraulic heads (head) and water temperatures in boreholes were monitored at 86 hydraulically-isolated depth intervals located 448.0 to 1,377.6 feet below land surface. The calculation of head is most sensitive to fluid pressure and the altitude of the pressure transducer at each port coupling; it is least sensitive to barometric pressure and water temperature. An analysis of errors associated with the head calculation determined the accuracy of an individual head measurement at +/- 2.3 feet. Many of the sources of measurement error are diminished when considering the differences between two closely-spaced readings of head; therefore, a +/- 0.1 foot measurement accuracy was assumed for vertical head differences (and gradients) calculated between adjacent monitoring zones. Vertical head and temperature profiles were unique to each borehole, and were characteristic of the heterogeneity and anisotropy of the eastern Snake River Plain aquifer. The vertical hydraulic gradients in each borehole remained relatively constant over time with minimum Pearson correlation coefficients between head profiles ranging from 0.72 at borehole USGS 103 to 1.00 at boreholes USGS 133 and MIDDLE 2051. Major inflections in the head profiles almost always coincided with low permeability sediment layers. The presence of a sediment layer, however, was insufficient for identifying the location of a major head change in a borehole. The vertical hydraulic gradients were defined for the major inflections in the head profiles and were as much as 2.2 feet per foot. Head gradients

  12. Uncertainty analysis of a combined Artificial Neural Network - Fuzzy logic - Kriging system for spatial and temporal simulation of Hydraulic Head.

    Tapoglou, Evdokia; Karatzas, George P.; Trichakis, Ioannis C.; Varouchakis, Emmanouil A.


    The purpose of this study is to evaluate the uncertainty, using various methodologies, in a combined Artificial Neural Network (ANN) - Fuzzy logic - Kriging system, which can simulate spatially and temporally the hydraulic head in an aquifer. This system uses ANNs for the temporal prediction of hydraulic head in various locations, one ANN for every location with available data, and Kriging for the spatial interpolation of ANN's results. A fuzzy logic is used for the interconnection of these two methodologies. The full description of the initial system and its functionality can be found in Tapoglou et al. (2014). Two methodologies were used for the calculation of uncertainty for the implementation of the algorithm in a study area. First, the uncertainty of Kriging parameters was examined using a Bayesian bootstrap methodology. In this case the variogram is calculated first using the traditional methodology of Ordinary Kriging. Using the parameters derived and the covariance function of the model, the covariance matrix is constructed. A common method for testing a statistical model is the use of artificial data. Normal random numbers generation is the first step in this procedure and by multiplying them by the decomposed covariance matrix, correlated random numbers (sample set) can be calculated. These random values are then fitted into a variogram and the value in an unknown location is estimated using Kriging. The distribution of the simulated values using the Kriging of different correlated random values can be used in order to derive the prediction intervals of the process. In this study 500 variograms were constructed for every time step and prediction point, using the method described above, and their results are presented as the 95th and 5th percentile of the predictions. The second methodology involved the uncertainty of ANNs training. In this case, for all the data points 300 different trainings were implemented having different training datasets each time

  13. Design of Hydraulic Gauge Head of Differential Pressure Type and Parameter Optimization of the Gauge Head%差压式液压测头的设计及参数优化

    母德强; 崔博; 范以撒; 陈懿


    The design and working principle of a hydraulic gauge head is intruced in this paper, which is based on the differential pressure-measuring principle with liquid as working media. With the help of CFX, the differential pres-sure system characteristics curves are plotted and the influence level of the structure parameters on working perfor-mance of the hydraulic gauge head is also analyzed. Bsides, the parameters of the gauge head are optimized.%提出一种以液体为工作介质,基于差压法的液压测头的设计和工作原理。利用CFX软件绘制了Δp-s工作曲线图,分析了各参数对液压测头工作性能的影响,对液压测头的几个重要参数进行了优化。

  14. Stimulation strength and focality of electroconvulsive therapy and magnetic seizure therapy in a realistic head model.

    Lee, Won Hee; Lisanby, Sarah H; Laine, Andrew F; Peterchev, Angel V


    This study examines the characteristics of the electric field (E-field) induced in the brain by electroconvulsive therapy (ECT) and magnetic seizure therapy (MST). The electric field induced by five ECT electrode configurations (bilateral, bifrontal, right unilateral, focal electrically administered seizure therapy, and frontomedial) as well as an MST coil configuration (circular) was computed in an anatomically realistic finite element model of the human head. We computed the maps of the electric field strength relative to an estimated neural activation threshold, and used them to evaluate the stimulation strength and focality of the various ECT and MST paradigms. The results show that the median ECT stimulation strength in the brain is 3-11 times higher than that for MST, and that the stimulated brain volume is substantially higher with ECT (47-100%) than with MST (21%). Our study provides insight into the observed reduction of cognitive side effects in MST compared to ECT, and supports arguments for lowering ECT current amplitude as a means of curbing its side effects.

  15. Effect of Neck Muscle Strength and Anticipatory Cervical Muscle Activation on the Kinematic Response of the Head to Impulsive Loads

    Eckner, James T.; Oh, Youkeun K.; Joshi, Monica S.; Richardson, James K.; Ashton-Miller, James A.


    Background Greater neck strength and activating the neck muscles to brace for impact are both thought to reduce an athlete's risk of concussion during a collision by attenuating the head's kinematic response after impact. However, the literature reporting the neck's role in controlling postimpact head kinematics is mixed. Furthermore, these relationships have not been examined in the coronal or transverse planes or in pediatric athletes. Hypotheses In each anatomic plane, peak linear velocity (DV) and peak angular velocity (Dv) of the head are inversely related to maximal isometric cervical muscle strength in the opposing direction (H1). Under impulsive loading, DV and Dv will be decreased during anticipatory cervical muscle activation compared with the baseline state (H2). Study Design Descriptive laboratory study. Methods Maximum isometric neck strength was measured in each anatomic plane in 46 male and female contact sport athletes aged 8 to 30 years. A loading apparatus applied impulsive test forces to athletes' heads in flexion, extension, lateral flexion, and axial rotation during baseline and anticipatory cervical muscle activation conditions. Multivariate linear mixed models were used to determine the effects of neck strength and cervical muscle activation on head DV and Dv. Results Greater isometric neck strength and anticipatory activation were independently associated with decreased head DV and Dv after impulsive loading across all planes of motion (all P\\.001). Inverse relationships between neck strength and head DV and Dv presented moderately strong effect sizes (r = 0.417 to r = 0.657), varying by direction of motion and cervical muscle activation. Conclusion In male and female athletes across the age spectrum, greater neck strength and anticipatory cervical muscle activation (“bracing for impact”) can reduce the magnitude of the head's kinematic response. Future studies should determine whether neck strength contributes to the observed sex and

  16. Fracture hydraulic conductivity in the Mexico City clayey aquitard: Field piezometer rising-head tests

    Vargas, Carlos; Ortega-Guerrero, Adrián

    A regional lacustrine aquitard covers the main aquifer of the metropolitan area of Mexico City. The aquitard's hydraulic conductivity (K') is fundamental for evaluating the natural protection of the aquifer against a variety of contaminants present on the surface and its hydraulic response. This study analyzes the distribution and variation of K' in the plains of Chalco, Texcoco and Mexico City (three of the six former lakes that existed in the Basin of Mexico), on the basis of 225 field-permeability tests, in nests of existing piezometers located at depths of 2-85 m. Tests were interpreted using the Hvorslev method and some by the Bouwer-Rice method. Results indicate that the distribution of K' fits log-Gaussian regression models. Dominant frequencies for K' in the Chalco and Texcoco plains range between 1E-09 and 1E-08 m/s, with similar population means of 1.19E-09 and 1.7E-09 m/s, respectively, which are one to two orders of magnitude higher than the matrix conductivity. In the Mexico City Plain the population mean is near by one order of magnitude lower; K'=2.6E-10 m/s. The contrast between the measured K' and that of the matrix is attributed to the presence of fractures in the upper 25-40 m, which is consistent with the findings of previous studies on solute migration in the aquitard. Un imperméable régional d'origine lacustre recouvre le principal aquifère de la zone urbaine de la ville de Mexico. La conductivité hydraulique K' de cet imperméable est fondamentale pour évaluer la protection naturelle de l'aquifère, contre les différents contaminants présents en surface, et sa réponse hydraulique. Cette étude analyse et les variations de K' dans les plaines de Chalco, Texcoco et Mexico (trois des six anciens lacs qui existaient dans le Bassin de Mexico), sur la base de 225 essais de perméabilité sur le terrain, réalisés en grappes dans des piézomètres existants entre 2 et 85 m de profondeur. Les essais ont été interprétés avec la m

  17. The variation of the strength of neck extensor muscles and semispinalis capitis muscle size with head and neck position.

    Rezasoltani, A; Nasiri, R; Faizei, A M; Zaafari, G; Mirshahvelayati, A S; Bakhshidarabad, L


    Semispinalis capitis muscle (SECM) is a massive and long cervico-thoracic muscle which functions as a main head and neck extensor muscle. The aim of this study was to detect the effect of head and neck positions on the strength of neck extensor muscles and size of SECM in healthy subjects. Thirty healthy women students voluntarily participated in this study. An ultrasonography apparatus (Hitachi EUB 525) and a system of tension-meter were used to scan the right SECM at the level of third cervical spine and to measure the strength of neck extensor muscles at three head and neck positions. Neck extensor muscles were stronger in neutral than flexion or than extension positions while the size of SECM was larger in extension than neutral or than flexion position. The force generation capacity of the main neck extensor muscle was lower at two head and neck flexion and extension positions than neutral position. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. A geostatistical methodology for the optimal design of space-time hydraulic head monitoring networks and its application to the Valle de Querétaro aquifer.

    Júnez-Ferreira, H E; Herrera, G S


    This paper presents a new methodology for the optimal design of space-time hydraulic head monitoring networks and its application to the Valle de Querétaro aquifer in Mexico. The selection of the space-time monitoring points is done using a static Kalman filter combined with a sequential optimization method. The Kalman filter requires as input a space-time covariance matrix, which is derived from a geostatistical analysis. A sequential optimization method that selects the space-time point that minimizes a function of the variance, in each step, is used. We demonstrate the methodology applying it to the redesign of the hydraulic head monitoring network of the Valle de Querétaro aquifer with the objective of selecting from a set of monitoring positions and times, those that minimize the spatiotemporal redundancy. The database for the geostatistical space-time analysis corresponds to information of 273 wells located within the aquifer for the period 1970-2007. A total of 1,435 hydraulic head data were used to construct the experimental space-time variogram. The results show that from the existing monitoring program that consists of 418 space-time monitoring points, only 178 are not redundant. The implied reduction of monitoring costs was possible because the proposed method is successful in propagating information in space and time.

  19. Locations, values, and uncertainties of hydraulic-head observations for the steady-state, prepumped period of the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    U.S. Geological Survey, Department of the Interior — This digital geospatial data set contains the locations, values, and uncertainties of 700 hydraulic-head observations used in the steady-state, prepumped period of...

  20. Evaluation of advanced hydraulic turbomachinery for underground pumped hydroelectric storage. Part 1. Single-stage regulated pump turbines for operating heads of 500 to 1000 m

    Frigo, A.A.; Blomquist, C.A.; Degnan, J.R.


    High-head, large-capacity turbomachinery is needed for the concept of underground pumped hydroelectric storage to be technically and economically attractive. Single-stage, reversible, Francis-type pump turbines with adjustable wicket gates appear to offer the most economically attractive option for heads between about 500 and 1000 m. The feasibility of developing these types of machines for capacities up to 500 MW and operating heads up to 1000 m has been evaluated. Preliminary designs have been generated for six single-stage pump turbines. The designs are for capacities of 350 and 500 MW and for operating heads of 500, 750, and 1000 m. The report contains drawings of the machines along with material specifications and hydraulic performance data. Mechanical, hydraulic, and economic analyses indicate that these machines will behave according to the criteria used to design them and that they can be built at a reasonable cost. The stress and deflection responses of the 500-MW, 100-m-head pump turbine, determined by detailed finite element analysis techniques, give solid evidence of the integrity of the conceptual designs of the six units and indicate no unsolvable problems. Results of a life expectancy analysis of the wicket gates indicate that a near infinite life can be expected for these components when they are subjected to normal design loads. Efficiencies of 90.7 and 91.4% in the generating and pumping modes, respectively, can be expected for the 500-MW, 1000-m-head unit. Performances of the other five machines are comparable. The specific costs of the pump turbines in mid-1978 US dollars per kW vary from 19.2 to 11.8 over a head range of from 500 to 1000 m for the 500-MW machines and from 20.0 to 12.3 for the 350-MW machines.

  1. Application of SVP-A Hydraulic Support Strength Test Simulation System%SVP-A液压支架强度试验仿真系统的应用



    文章详细介绍了SVP-A液压支架强度试验仿真系统的实体模型及应用状况,分析了液压支架结构的应力分布特点,得出该系统具有较好的实用性和可普及性,是进行液压支架研究设计的有效工具。%This paper introduces the application of strength of SVP-A hydraulic support test simulation system, analysis of the structure characteristic of hydraulic support's stress distribution, the author concluded that the system has good practicability and universality, it is also a powerful tool for the study of hydraulic support design.

  2. Multilevel groundwater monitoring of hydraulic head and temperature in the eastern Snake River Plain aquifer, Idaho National Laboratory, Idaho, 2009–10

    Twining, Brian V.; Fisher, Jason C.


    During 2009 and 2010, the U.S. Geological Survey’s Idaho National Laboratory Project Office, in cooperation with the U.S. Department of Energy, collected quarterly, depth-discrete measurements of fluid pressure and temperature in nine boreholes located in the eastern Snake River Plain aquifer. Each borehole was instrumented with a multilevel monitoring system consisting of a series of valved measurement ports, packer bladders, casing segments, and couplers. Multilevel monitoring at the Idaho National Laboratory has been ongoing since 2006. This report summarizes data collected from three multilevel monitoring wells installed during 2009 and 2010 and presents updates to six multilevel monitoring wells. Hydraulic heads (heads) and groundwater temperatures were monitored from 9 multilevel monitoring wells, including 120 hydraulically isolated depth intervals from 448.0 to 1,377.6 feet below land surface. Quarterly head and temperature profiles reveal unique patterns for vertical examination of the aquifer’s complex basalt and sediment stratigraphy, proximity to aquifer recharge and discharge, and groundwater flow. These features contribute to some of the localized variability even though the general profile shape remained consistent over the period of record. Major inflections in the head profiles almost always coincided with low-permeability sediment layers and occasionally thick sequences of dense basalt. However, the presence of a sediment layer or dense basalt layer was insufficient for identifying the location of a major head change within a borehole without knowing the true areal extent and relative transmissivity of the lithologic unit. Temperature profiles for boreholes completed within the Big Lost Trough indicate linear conductive trends; whereas, temperature profiles for boreholes completed within the axial volcanic high indicate mostly convective heat transfer resulting from the vertical movement of groundwater. Additionally, temperature profiles

  3. Effects of carbon percentage, Stelmor cooling rate and laying head temperature on tensile strength gain in low carbon steels

    Gade, Surya Prakash

    Low carbon steel wire rods are used to produce finished products such as fine wire, coat hangers, staples, and roofing nails. These products are subjected to excessively high work hardening rates during wire drawing process resulting in a variation in wire tensile strength. This research analyzes the effects of carbon percentage, StelmorRTM cooling rate and laying head temperature on the tensile strength gain in wire drawn low carbon steels using design of experiments. The probable reasons for variations in tensile strength gain are analyzed by observing the microstructural changes during experiments. Microstructural analysis was done extensively using optical microscope and Transmission Electron Microscope (TEM) and it was found that the tensile strength gain variation is mainly caused by the increase in the dislocation density in wire rod and wire due to high cooling rate and high laying head temperature, within the range considered. This research concludes that a low carbon wire rod can be produced with minimum tensile strength gain, lower dislocation density and finer ferrite grain size by maintaining a low cooling rate in the StelmorRTM cooling zone and low laying head temperature, which is the temperature at which the wire rod coils are laid on the Stelmor RTM deck. It is also concluded from the results of the present study that: (1) The lowest tensile strength gain is for NS 1006T-3 (0.07 wt.% Carbon) with low cooling rate of 14°F/s and low laying head temperature of 1500°F. (2) The highest tensile strength gain is for NS 1006T-3 with high cooling rate of 26°F/s and high laying head temperature of 1650°F. (3) The effect of StelmorRTM cooling rate and laying head temperature and their interaction are found to be the significant factors causing the variation in wire tensile strength gain. The StelmorRTM cooling rate has the most significant effect on tensile strength gain among the three factors. (4) The effect of carbon percentage on wire tensile strength

  4. Isotopic and Hydraulic Head Evidence for Cross-formational Leakage of Saline Water From the Rio Grande Alluvium to the Hueco Bolson Aquifer, Trans-Pecos Texas

    Hibbs, B. J.; Eastoe, C. J.; Bangs, E.; Reinert, S.


    The twin-cities of El Paso and Juarez share the water resources of the Hueco Bolson, a Tertiary and Quaternary basin fill aquifer that spans the international border. Artesian conditions existed in the El Paso-Juarez Valley during predevelopment times, and dilute groundwaters in the Hueco Bolson flowed upward and mixed with the mineralized water in the shallow Rio Grande alluvium (alluvial deposits less than 60 m thick). The hydraulic gradient has been reversed since predevelopment times by heavy municipal pumping in the Hueco Bolson aquifer, and many of the deeper wells in the El Paso-Juarez Valley have been retired due to salinity exceeding 1500 mg/L TDS. Previous studies based on groundwater modeling suggested that salinity increased in deeper wells due to induced leakage of saline water from the shallow Rio Grande alluvium. Hydrochemical, isotopic and hydraulic head data collected in this study support this model. Tritium levels in several deeper wells in the El Paso-Juarez Valley (screens set from 90 to 210 m) vary from 1.2 to 7.9 TU, indicating post-bomb water from leakage from the Rio Grande and Rio Grande alluvium. The hydraulic head gradient is oriented vertically downward between the alluvial and bolson aquifers, reaching 0.14 (27 m/189 m) in one well nest. Groundwater from the same well nest gives δ18O and δ2H values plotting along a mixing curve, representing evaporated and saline waters in shallow alluvial wells (-7.2 to -8.3 δ18O \\permil, -66 to -71 δ2H \\permil), meteoric and dilute waters in the deepest bolson well (-10.7 δ18O \\permil, -76 δ2H \\permil), and intermediate and mixed saline water in middle bolson wells (-9.8 to -10.3 δ18O \\permil, -76 to -77 δ2H \\permil).

  5. Effects of leg strength and bicycle ergometry exercise on cardiovascular deconditioning after 30-day head-down bed rest

    Wu, Bin; Liu, Yusheng; Sun, Hongyi; Zhao, Dongming; Wang, Yue; Wu, Ping; Ni, Chengzhi


    The purpose of this study is to determine if the intermittent leg muscular strength exercise and bicycle ergometry exercise could attenuate cardiovascular deconditioning induced by prolonged -6° head-down bed rest (HDBR). Fifteen male subjects were randomly allocated into group A ( n=5, 30 days HDBR without exercise), group B ( n=5, 30 days HDBR with leg muscular strength exercise) and group C ( n=5, 30 days HDBR with bicycle ergometry exercise). The orthostatic tolerance (OT) was determined by +75°/20 min head-up tilt (HUT) test and the submaximal exercise capacity was determined by bicycle ergometry before and after HDBR. The results were as follows: (1) Compared with that before HDBR, OT time decreased dramatically by 57.6% ( pexercise time decreased significantly by 17.7% ( p0.77) in group C. (3) compared with that before HDBR, the changes of heart rate (HR) and blood pressure were slightly improved in group B and C, while deteriorated in group A during orthostatic test and exercise test after HDBR. The results indicate that leg muscular strength exercise and bicycle ergometry exercise could partially attenuate the cardiovascular deconditioning induced by 30 d HDBR, and the latter exercise training could fully provide the protection for the loss of exercise capacity.

  6. Hydraulic Actuators with Autonomous Hydraulic Supply for the Mainline Aircrafts

    I. S. Shumilov


    Full Text Available Applied in the aircraft control systems, hydraulic servo actuators with autonomous hydraulic supply, so-called, hydraulic actuators of integrated configuration, i.e. combination of a source of hydraulic power and its load in the single unit, are aimed at increasing control system reliability both owing to elimination of the pipelines connecting the actuator to the hydraulic supply source, and owing to avoidance of influence of other loads failure on the actuator operability. Their purpose is also to raise control system survivability by eliminating the long pipeline communications and their replacing for the electro-conductive power supply system, thus reducing the vulnerability of systems. The main reason for a delayed application of the hydraulic actuators in the cutting-edge aircrafts was that such aircrafts require hydraulic actuators of considerably higher power with considerable heat releases, which caused an unacceptable overheat of the hydraulic actuators. Positive and negative sides of the hydraulic actuators, their alternative options of increased reliability and survivability, local hydraulic systems as an advanced alternative to independent hydraulic actuators are considered.Now to use hydraulic actuators in mainline aircrafts is inexpedient since there are the unfairly large number of the problems reducing, first and last, safety of flights, with no essential weight and operational advantages. Still works to create competitive hydraulic actuators ought to be continued.Application of local hydraulic systems (LHS will allow us to reduce length of pressure head and drain pipelines and mass of pipelines, as well as to raise their general fail-safety and survivability. Application of the LHS principle will allow us to use a majority of steering drive advantages. It is necessary to allocate especially the following:- ease of meeting requirements for the non-local spread of the engine weight;- essentially reducing length and weight of

  7. Enhancement of force generated by individual myosin heads in skinned rabbit psoas muscle fibers at low ionic strength.

    Haruo Sugi

    Full Text Available Although evidence has been presented that, at low ionic strength, myosin heads in relaxed skeletal muscle fibers form linkages with actin filaments, the effect of low ionic strength on contraction characteristics of Ca(2+-activated muscle fibers has not yet been studied in detail. To give information about the mechanism of muscle contraction, we have examined the effect of low ionic strength on the mechanical properties and the contraction characteristics of skinned rabbit psoas muscle fibers in both relaxed and maximally Ca(2+-activated states. By progressively decreasing KCl concentration from 125 mM to 0 mM (corresponding to a decrease in ionic strength μ from 170 mM to 50 mM, relaxed fibers showed changes in mechanical response to sinusoidal length changes and ramp stretches, which are consistent with the idea of actin-myosin linkage formation at low ionic strength. In maximally Ca(2+-activated fibers, on the other hand, the maximum isometric force increased about twofold by reducing KCl concentration from 125 to 0 mM. Unexpectedly, determination of the force-velocity curves indicated that, the maximum unloaded shortening velocity Vmax, remained unchanged at low ionic strength. This finding indicates that the actin-myosin linkages, which has been detected in relaxed fibers at low ionic strength, are broken quickly on Ca(2+ activation, so that the linkages in relaxed fibers no longer provide any internal resistance against fiber shortening. The force-velocity curves, obtained at various levels of steady Ca(2+-activated isometric force, were found to be identical if they are normalized with respect to the maximum isometric force. The MgATPase activity of muscle fibers during isometric force generation was found not to change appreciably at low ionic strength despite the two-fold increase in Ca(2+-activated isometric force. These results can be explained in terms of enhancement of force generated by individual myosin heads, but not by any

  8. Isokinetic and isometric strength-endurance after 6 hours of immersion and 6 degrees head-down tilt in men

    Shaffer-Bailey, M.; Greenleaf, J. E.; Hutchinson, T. M.


    PURPOSE: To determine weight (water) loss levels for onset of muscular strength and endurance changes during deconditioning. METHODS: Seven men (27-40 yr) performed maximal shoulder-, knee-, and ankle-joint isometric (0 degree.s(-1) load) and isokinetic (60 degrees, 120 degrees, 180 degrees.s(-1) velocity) exercise tests during ambulatory control (AC), after 6 h of 6 degrees head-down tilt (HDT; dry-bulb temp. = 23.2 +/- SD 0.6 degrees C, relative humidity = 31.1+/- 11.1%) and after 6 h of 80 degrees foot-down head-out water immersion (WI; water temp. = 35.0 +/- SD 0.1 degree C) treatments. RESULTS: Weight (water) loss after HDT (1.10 +/- SE 0.14 kg, 1.4 +/- 0.2% body wt) and WI (1.54+/- 0.19 kg, 2.0 +/- 0.2% body wt) were not different, but urinary excretion with WI (1,354 +/- 142 ml.6 h(-1)) was 28% greater (p knee at 180 degrees.s(-1) for 30 s) was not different between AC and the WI or HDT treatments. Shoulder-, knee-, and ankle-joint strength was unchanged except for three knee-joint peak torques: AC torque (120 degrees.s(-1), 285 +/- 20 Nm) decreased to 268 +/- 21 Nm (delta = -6%, p torques (180 degrees.s(-1), 260 +/- 19 Nm) decreased to 236 +/- 15 Nm (delta = -9%, p joint strength and endurance decrements is more than 2% body weight (water) loss, while significant reduction in knee-joint muscular strength-endurance occurred only at moderate (120 degrees.s(-1) and lighter (180 degrees.s(-1)) loads with body weight loss of 1.4-2.0% following WI or HDT, respectively. These weight (water) losses and knee-joint strength decrements are somewhat less than the mean weight loss of 2.6% and knee-joint strength decrements of 6-20% of American astronauts after Skylab flights to 84 d.

  9. Unusually extensive head trauma in a hydraulic elevator accident: post-mortem MSCT findings, autopsy results and scene reconstruction.

    Jacobsen, Christina; Schön, Corinna A; Kneubuehl, Beat; Thali, Michael J; Aghayev, Emin


    Accidental or intentional falls from a height are a form of blunt trauma and occur frequently in forensic medicine. Reports describing elevator accidents as a small subcategory of falls from heights are rare in the medical literature and no report on injury patterns or scene reconstruction of such an accident was found. A case of an accident in a hydraulic elevator with a man falling 3m was examined using post-mortem multi-slice computed tomography (MSCT) and autopsy. The man suffered an unusually extensive trauma and died at the scene. Post-mortem MSCT examination showed a comminute fracture of the skull, the right femur and the first lumbar vertebra. Severe lacerations of the brain with epidural, subdural and subarachnoidal haemorrhages over both hemispheres were diagnosed. Autopsy confirmed these findings. To reconstruct the accident we used radiological and autopsy results as well as findings at the scene.

  10. Hydraulic continuity and biological effects of low strength very low frequency electromagnetic waves: Case of microbial biofilm growth in water treatment.

    Gérard, Merlin; Noamen, Omri; Evelyne, Gonze; Eric, Valette; Gilles, Cauffet; Marc, Henry


    This study aims to elucidate the interactions between water, subjected to electromagnetic waves of very low frequency (VLF) (kHz) with low strength electromagnetic fields (3.5 mT inside the coils), and the development of microbial biofilms in this exposed water. Experimental results demonstrate that in water exposed to VLF electromagnetic waves, the biomass of biofilm is limited if hydraulic continuity is achieved between the electromagnetic generator and the biofilm media. The measured amount of the biofilm's biomass is approximately a factor two lower for exposed biofilm than the non-exposed biofilm. Measurements of electromagnetic fields in the air and simulations exhibit very low intensities of fields (electromagnetic generator. Exposure to electric and magnetic fields of the quoted intensities cannot explain thermal and ionizing effects on the biofilm. A variable electrical potential with a magnitude close to 20 mV was detected in the tank in hydraulic continuity with the electromagnetic generator. The application of quantum field theory may help to explain the observed effects in this case.

  11. Neuromagnetic field strength outside the human head due to impedance changes from neuronal depolarization.

    Ahadzi, G M; Liston, A D; Bayford, R H; Holder, D S


    The holy grail of neuroimaging would be to have an imaging system, which could image neuronal electrical activity over milliseconds. One way to do this would be by imaging the impedance changes associated with ion channels opening in neuronal membranes in the brain during activity. In principle, we could measure this change by using electrical impedance tomography (EIT) but it is close to its threshold of detectability. With the inherent limitation in the use of electrodes, we propose a new scheme based on recording the magnetic field resulting from an injected current with superconducting quantum interference devices (SQUIDs), used in magnetoencephalography (MEG). We have performed a feasibility study using computer simulation. The head was modelled as concentric spheres to mimic the scalp, skull, cerebrospinal fluid and brain using the finite element method. The magnetic field 1 cm away from the scalp was estimated. An impedance change of 1% in a 2 cm radius volume in the brain was modelled as the region of depolarization. A constant current of 100 microA was injected into the head from diametrically opposite electrodes. The model predicts that the standing magnetic field is about 10 pT and changed by about 3 fT (0.03%) on depolarization. The spectral noise density in a typical MEG system in the frequency band 1-100 Hz is about 7 fT, so this places the change at the limit of detectability. This is similar to electrical recording, as in conventional EIT systems, but there may be advantages to MEG in that the magnetic field directly traverses the skull and instrumentation errors from the electrode-skin interface will be obviated.

  12. Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS-6 test data report : thermal hydraulic results, Rev. 0.

    Lomperski, S.; Farmer, M. T.; Kilsdonk, D.; Aeschlimann, B. (Nuclear Engineering Division)


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure? (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are being conducted to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium ({approx} {phi} 30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. The issue of crust strength is being addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus measures the fracture strength of the crust while it is either at room temperature or above, the latter state being achieved with a heating element placed below the crust. The two apparatuses used to measure the melt quench rate and crust strength are jointly referred to as SSWICS (Small-Scale Water Ingression and Crust Strength). This report describes results of the sixth water ingression test, designated SSWICS-6. This test

  13. Influence of geometry and materials on the axial and torsional strength of the head-neck taper junction in modular hip replacements: A finite element study.

    Fallahnezhad, Khosro; Farhoudi, Hamidreza; Oskouei, Reza H; Taylor, Mark


    The assembly force is important in establishing the mechanical environment at the head-neck taper junction of modular hip replacements. Previous experimental results of the assembled taper junctions with different material combinations (Co-28Cr-6Mo and Ti-6Al-4V) reported similar axial strengths (pull-off loads), but lower torsional strengths (twist-off moments) for the CoCr/CoCr junction. However, mechanics of the junction and the strength behaviour have not been understood yet. A three dimensional finite element model of an isolated femoral head-neck junction was developed to explore the assembly and disassembly procedures, particularly the axial and torsional strengths for different material combinations and geometries. Under the same assembly load, the contacting length between the CoCr head and titanium neck was greater than that of in CoCr/CoCr. The contact length in the titanium neck was more sensitive to the assembly force when compared to the CoCr neck. For instance, with increasing the assembly force from 1890 to 3700N, the contact length increased by 88% for CoCr/Ti and 59% for CoCr/CoCr junctions. The torsional strength of the junction was related to the lateral deformation of the neck material due to the applied moment. The angular mismatch existing between the head and neck components was found to play the main role in the torsional strength of the junction. The smaller mismatch angle the higher torsional strength. It is suggested to consider reducing the mismatch angle, particularly in CoCr/CoCr junctions, and ensure a sufficiently high assembly force is applied by impaction for this combination.

  14. Empowering Head Start African American and Latino Families: Promoting Strengths-Based Parenting Characteristics through Child Parent Relationship Training--An Evidence-Based Group Parenting Program

    Sheely-Moore, Angela I.; Ceballos, Peggy L.


    With the tendency of low-income African American and Latino children identified at-risk for school readiness and school success compared to their early-childhood counterparts, Head Start personnel are challenged to examine the role of family strengths in the promotion of academic success for these populations. This article provides a rationale for…

  15. 超低水头水轮机流动数值模拟及水力性能研究%Research on Flow Numerical Simulation and Hydraulic Performance of Ultra Low-head Water Turbine



    In order to develop economical and practical ultra low-head turbine (the net head low than 5m),the internal flow of ultra low-head water turbine with utilization of water and wave energy for generation is simulated by using computational fluid dynamics technology.The efficiency of the entire turbine is predicted and the hydraulic characteristics of the ultra low-head water turbine are analyzed.In the 1.5-5m head range,numerical simulations show that the ultra low-head water turbine has relatively high and slowly changing efficiency,and its output power basically depends on the head.%为开发经济实用超低水头(净水头低于5 m)的水轮机,基于流体动力学理论对可应用于水能、波浪能发电的某超低水头水轮机进行了内部流动数值模拟及性能预测,并分析了水头和转速特性.结果表明,在1.5~5.0m水头范围内,水轮机效率较高,变化平稳,输出功率主要取决于水头.

  16. In-situ falling-head test for hydraulic conductivity: Evaluation in layered sediments of an analysis derived for homogenous sediments

    Burnette, Matthew C.; Genereux, David P.; Birgand, François


    The hydraulic conductivity (K) of streambeds is a critical variable controlling interaction of groundwater and surface water. The Hvorslev analysis for estimating K from falling-head test data has been widely used since the 1950s, but its performance in layered sandy sediments common in streams and lakes has not previously been examined. Our numerical simulations and laboratory experiments show that the Hvorslev analysis yields accurate K values in both homogenous sediment (for which the analysis was originally derived) and layered deposits with low-K sand over high-K sand. K from the Hvorslev analysis deviated significantly from true K only when two conditions were present together: (1) high-K sand was present over low-K sand, and (2) the bottom of the permeameter in which K was measured was at or very near the interface between high-K and low-K. When this combination of conditions exists, simulation and laboratory sand tank results show that in-situ Hvorslev K underestimates the true K of the sediment within a permeameter, because the falling-head test is affected by low-K sediment outside of (below the bottom of) the permeameter. In simulation results, the maximum underestimation (occurring when the bottom of the permeameter was at the interface of high K over low K) was by a factor of 0.91, 0.59, and 0.12 when the high-K to low-K ratio was 2, 10, and 100, respectively. In laboratory sand tank experiments, the underestimation was by a factor of about 0.83 when the high-K to low-K ratio was 2.3. Also, this underestimation of K by the Hvorslev analysis was about the same whether the underlying low-K layer was 2 cm or 174 cm thick (1% or 87% of the domain thickness). Numerical model simulations were useful in the interpretation of in-situ field K profiles at streambed sites with layering; specifically, scaling the model results to the maximum measured K at the top of the field K profiles helped constrain the likely ratio of high K to low K at field locations with

  17. Water Treatment Technology - Hydraulics.

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on hydraulics provides instructional materials for three competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: head loss in pipes in series, function loss in…

  18. A study of the key problem of optimum hydraulic design for a pump system with low head%低扬程泵装置优化水力设计的关键问题

    徐磊; 陆林广; 梁金栋; 王刚; 董雷


    An in-depth study on the problem of optimum hydraulic design for a pump system with low head has been made in this paper. The efficiency of a pump system with low head is divided into two aspects: one is pump efficiency and the other is conduit efficiency. Some problems about the definition of pump segment in the pump system, efficiency modification for the pump segment and flow pattern of inlet conduit in the pump system are discussed. The influence of conduit hydraulic loss on the conduit efficiency and pump system efficiency is analyzed and the influence of both flow velocity and flow pattern on the conduit hydraulic loss is illustrated by calculation samples, from which the conclusions are drawn as follows: under the condition of low head, the key problem of how to increase the pump system efficiency is to reduce the conduit hydraulic loss as much as possible; The essential way to reduce the conduit hydraulic loss may be to lower the flow velocity and improve the flow pattern in the conduit. The approaches to reduce the conduit hydraulic loss mainly include: to choose the type of pump system and conduit with the optimal hydraulic performance, to suitably lower pump nD value, to choose better pump model, to suitably relax the restrictions for conduit control size, and to sufficiently optimize hydraulic design for conduit shape.%对低扬程泵装置的优化水力设计问题进行了较为深入的研究.将低扬程泵装置效率分解为水泵效率和流道效率两个方面,讨论了泵装置中泵段的概念和泵段效率的修正等问题,分析了流道水力损失对流道效率及泵装置效率的影响,通过实例说明了流道内的流速和流态对流道水力损失的影响,得到以下结论:在低扬程条件下,尽可能减小流道水力损失是提高泵装置效率的关键;减小流道水力损失的关键是降低流道内的流速和改善流道内的流态,其途径主要包括选择水力性能最优的泵装置型式和流道

  19. Hydraulic structures

    Chen, Sheng-Hong


    This book discusses in detail the planning, design, construction and management of hydraulic structures, covering dams, spillways, tunnels, cut slopes, sluices, water intake and measuring works, ship locks and lifts, as well as fish ways. Particular attention is paid to considerations concerning the environment, hydrology, geology and materials etc. in the planning and design of hydraulic projects. It also considers the type selection, profile configuration, stress/stability calibration and engineering countermeasures, flood releasing arrangements and scouring protection, operation and maintenance etc. for a variety of specific hydraulic structures. The book is primarily intended for engineers, undergraduate and graduate students in the field of civil and hydraulic engineering who are faced with the challenges of extending our understanding of hydraulic structures ranging from traditional to groundbreaking, as well as designing, constructing and managing safe, durable hydraulic structures that are economical ...

  20. 高水头水轮机底环的刚强度研究%Study on the Stiffness and Strength of the High Head Hydroturbine Bottom Ring

    陈光辉; 庞立军


    本文对高水头水轮机底环采用单独受力分析和联合受力分析的方法进行了有限元分析与对比,同时对底环进行结构优化和动态特性分析.%In this paper, the stiffness and strength of the high head hydroturbine bottom ring were studied by two methods of independent force analysis and unite force analysis, and the results were compared. At the same time, the structure of the bottom ring was optimized and the dynamic characteristic was analysed.


    Wiegand, D.E.


    A hydraulic servo is designed in which a small pressure difference produced at two orifices by an electrically operated flapper arm in a constantly flowing hydraulic loop is hydraulically amplified by two constant flow pumps, two additional orifices, and three unconnected ball pistons. Two of the pistons are of one size and operate against the additional orifices, and the third piston is of a different size and operates between and against the first two pistons. (AEC)

  2. Evaluation of advanced hydraulic turbomachinery for underground pumped hydroelectric storage. Part 2. Two-stage regulated pump/turbines for operating heads of 1000 to 1500 m

    Blomquist, C.A.; Frigo, A.A.; Degnan, J.R.


    This UPHS report applies to Francis-type, reversible pump/turbines regulated with gating systems. The first report, however, covered single-stage regulations; this report covers two-stage regulations. Development of a two-stage regulated pump/turbine appears to be attractive because the proposed single-drop UPHS concept requires turbomachinery with a head range of 1000 to 2000 m. With turbomachinery of this range available, the single-drop scheme offers a simple and economic UPHS option. Six different two-stage, top-gated pump/turbines have been analyzed: three that generate 500 MW and three that generate 350 MW. In each capacity, one machine has an operating head of 1000 m, another has a head of 1250 m, and the third has a head of 1500 m. The rated efficiencies of the machines vary from about 90% (1000-m head) to about 88% (1500-m head). Costs in 1978 $/kW for the three 500-MW units are: 20.5 (1000 m), 16.5 (1250 m), and 13.5 (1500 m). Corresponding costs for the three 350-MW units are 23, 18, and 14 $/kW. No major turbomachinery obstacles are foreseen that could hamper development of these pump/turbines. Further model testing and development are needed before building them.

  3. Basic hydraulics

    Smith, P D


    BASIC Hydraulics aims to help students both to become proficient in the BASIC programming language by actually using the language in an important field of engineering and to use computing as a means of mastering the subject of hydraulics. The book begins with a summary of the technique of computing in BASIC together with comments and listing of the main commands and statements. Subsequent chapters introduce the fundamental concepts and appropriate governing equations. Topics covered include principles of fluid mechanics; flow in pipes, pipe networks and open channels; hydraulic machinery;

  4. Hydraulic Structures

    Department of Homeland Security — This table is required whenever hydraulic structures are shown in the flood profile. It is also required if levees are shown on the FIRM, channels containing the...

  5. Maneuvering impact boring head

    Zollinger, W. Thor; Reutzel, Edward W.


    An impact boring head may comprise a main body having an internal cavity with a front end and a rear end. A striker having a head end and a tail end is slidably mounted in the internal cavity of the main body so that the striker can be reciprocated between a forward position and an aft position in response to hydraulic pressure. A compressible gas contained in the internal cavity between the head end of the striker and the front end of the internal cavity returns the striker to the aft position upon removal of the hydraulic pressure.

  6. Comparison of electric field strength and spatial distribution of electroconvulsive therapy and magnetic seizure therapy in a realistic human head model

    Lee, Won Hee; Lisanby, Sarah H.; Laine, Andrew F.; Peterchev, Angel V.


    Background This study examines the strength and spatial distribution of the electric field induced in the brain by electroconvulsive therapy (ECT) and magnetic seizure therapy (MST). Methods The electric field induced by standard (bilateral, right unilateral, and bifrontal) and experimental (focal electrically administered seizure therapy and frontomedial) ECT electrode configurations as well as a circular MST coil configuration was simulated in an anatomically realistic finite element model of the human head. Maps of the electric field strength relative to an estimated neural activation threshold were used to evaluate the stimulation strength and focality in specific brain regions of interest for these ECT and MST paradigms and various stimulus current amplitudes. Results The standard ECT configurations and current amplitude of 800–900 mA produced the strongest overall stimulation with median of 1.8–2.9 times neural activation threshold and more than 94% of the brain volume stimulated at suprathreshold level. All standard ECT electrode placements exposed the hippocampi to suprathreshold electric field, although there were differences across modalities with bilateral and right unilateral producing respectively the strongest and weakest hippocampal stimulation. MST stimulation is up to 9 times weaker compared to conventional ECT, resulting in direct activation of only 21% of the brain. Reducing the stimulus current amplitude can make ECT as focal as MST. Conclusions The relative differences in electric field strength may be a contributing factor for the cognitive sparing observed with right unilateral compared to bilateral ECT, and MST compared to right unilateral ECT. These simulations could help understand the mechanisms of seizure therapies and develop interventions with superior risk/benefit ratio. PMID:27318858

  7. OECD MCCI project Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS-1 test data report : thermal hydraulic results. Rev. 0 September 20, 2002.

    Lomperski, S.; Farmer, M. T.; Kilsdonk, D. J.; Aeschlimann, R. W.; Basu, S. (Nuclear Engineering Division); (NRC)


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure and (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are being conducted to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium ({approx}{phi}30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. The issue of crust strength will be addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus will measure the fracture strength of the crust while under a thermal load created by a heating element beneath the crust. The two apparatuses used to measure the melt quench rate and crust strength are jointly referred to as SSWICS (Small-Scale Water Ingression and Crust Strength). This report describes results of the first water ingression test, designated SSWICS-1. The report includes a description of the test apparatus, the

  8. OECD MMCI Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS-2 test data report : thermal hydraulic results, Rev. 0 September 20, 2002.

    Lomperski, S.; Farmer, M. T.; Kilsdonk, D. J.; Aeschlimann, R. W.; Basu, S. (Nuclear Engineering Division); (NRC)


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure and (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are being conducted to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium ({approx}{phi}30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. The issue of crust strength will be addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus will measure the fracture strength of the crust while under a thermal load created by a heating element beneath the crust. The two apparatuses used to measure the melt quench rate and crust strength are jointly referred to as SSWICS (Small-Scale Water Ingression and Crust Strength). This report describes results of the second water ingression test, designated SSWICS-2. The report includes a description of the test apparatus, the

  9. OECD MCCI Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS-3 test data report : thermal Hydraulic results, Rev. 0 February 19, 2003.

    Lomperski, S.; Farmer, M. T.; Kilsdonk, D.; Aeschlimann, B. (Nuclear Engineering Division)


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure and (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are being conducted to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium ({approx}{phi}30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. The issue of crust strength will be addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus will measure the fracture strength of the crust while under a thermal load created by a heating element beneath the crust. The two apparatuses used to measure the melt quench rate and crust strength are jointly referred to as SSWICS (Small-Scale Water Ingression and Crust Strength). This report describes results of the third water ingression test, designated SSWICS-3. This test investigated the quenching behavior of a fully

  10. 高水头条件下氯离子击穿高岭土衬垫的离心模型试验研究%Centrifuge Modeling for Chloridion Breaking Through Kaolin Clay Liner with High Hydraulic Head

    詹良通; 曾兴; 李育超; 钟孝乐; 陈云敏


    One-dimensional chloridion movement in a Kaolin clay liner is modeled by using 400 g-t. Centrifuge machine, liner model is prepared by consolidating a high water content Kaolin slurry in 1 g condition. The breakthrough of chloridion in the Kaolin clay liner under high hydraulic head is successfully simulated at SO g centrifugal acceleration for 3 hours and 52 minutes. The results indicate the liner model experienced further consolidation in the centrifuge due to the induced seepage force, and the consolidation-induced seepage resulted in a transient flow in the early stage. The transient flow influenced the chloridion movement process, which is inconsistent with the condition of Ogata's analytical solution (1961) for one-dimensional advection-dispersion problem. An equivalent time method is proposed in this paper to analyze the test results. The prototype breakthrough time was predicted by the fitted parameters. The experimental results demonstrated that under a hydraulic head of 10 m, the breakthrough time for 2 m-thick Kaolin clay liner with a hydraulic conductivity of 3.2 x 10-9 m/s was 1.97 year, and the stable leakage rate was 0.604 m/yr.%利用400 g-t土工离心机模拟了高水头条件下氯离子在高岭土衬垫中的一维运移及击穿过程.在1g条件下采用高含水率的高岭土泥浆加压固结制备形成衬垫模型,离心模型试验离心加速度50 g,历时3 h 52 min,成功模拟了高水头条件下氯离子击穿黏土衬垫的过程.试验结果表明:离心状态下模型在高渗透压力作用发生再固结,在约30 min固结过程中模型发生了非稳定渗流,对早期污染物运移过程具有一定的影响,导致该运移过程与Ogata (1961)提出的污染物一维对流-扩散解析解的求解条件有所差异.采用等效时间的方法对试验结果进行拟合,根据拟合的参数预测原型的击穿时间,发现渗透系数为3.2×10-9 m/s的2 m厚黏土衬垫在上覆10 m水头作用下的击穿时间仅为1


    Teodor Eugen Man


    Full Text Available This paper presents two examples of exploitation of water energy that can be used in the irrigation field. First of theseexamples is the hydraulic transformer type A. Barglazan used for irrigation, pumped water is taken directly from theriver’s well, using a hydraulic pump which simultaneously carried out a double transformation in this way: hydraulicenergy into mechanic energy and mechanical energy into hydraulic energy. Technology preparation and devices designwas done in record time, seeing that this constructive solution is more robust, reliable and with improved energyperformance versus the laboratory prototype. The experimental research which was made at 1:1 scale proved theirgood function over time. Another example is the hydraulic hammer (hydraulic pump that uses low-head energy topump water, with a global efficiency of about 10 - 50%. Currently, the new situation of private ownership of landprovides conditions for new pumping microstations to be made where irrigation is necessary and optimal hydrauliclocations exist.

  12. 风力发电机组液压变桨机构运动与强度分析%Analysis on kinematics and strength of the hydraulic pitch mechanism of a wind turbine

    张锁怀; 贾坤; 张平满


    After the Solidworks model being inputted into the ANSYS software, the file of mode is created,and the original rigid body is replaced with the flexible body to build a mixed rigid and flexible body model in ADAMS.Then kinematic accuracy of the pitch mechanism of a wind turbine is analyzed, which results show that the difference of the pitch angle and speed exist between the actual and theoretical value due to the elastic deformation of the parts and the hydraulic oil, therefore monitoring sensors are proposed to be fixed on the blade plate and used to control the hydraulic cylinder motion and compensate the moving errorA file related with loads information of the key parts is created after motion simulation. After the file being input in ANSYS,the strength of the key parts is analyzed Based on the results,the location, where the material was easy to yield or the maximum stress exist,is found,which should be protected during designing.%将各个构件的Solidworks实体模型导入ANSYS中,生成柔性体模态中性文件,将该柔性体导入ADAMS中替换原有的刚性体,建立变桨机构的刚柔混合体模型.利用ADAMS对风力发电机组变桨机构的模型进行变桨精度分析,发现实际变桨速度和角位移与理论值有一定误差,提出了在桨叶盘上增设位置传感器,利用传感器发出的信号控制液压缸动作,对变桨误差进行补偿;将运动仿真过程中产生的零件载荷文件,导入ANSYS中,对关键零件进行强度分析,指出了各零件易破坏位置与最大应力位置,设计时应注意保护.

  13. Hydraulic characterization of " Furcraea andina

    Rivera-Velasquez, M. F.; Fallico, C.; Molinari, A.; Santillan, P.; Salazar, M.


    The present level of pollution, increasingly involving groundwaters, constitutes a serious risk for environment and human health. Therefore the remediation of saturated and unsaturated soils, removing pollutant materials through innovative and economic bio-remediation techniques is more frequently required. Recent studies on natural fiber development have shown the effectiveness of these fibers for removal of some heavy metals, due to the lignin content in the natural fibers which plays an important role in the adsorption of metal cations (Lee et al., 2004; Troisi et al., 2008; C. Fallico, 2010). In the context of remediation techniques for unsaturated and/or saturated zone, an experimental approach for the hydraulic characterization of the "Furcraea andina" (i.e., Cabuya Blanca) fiber was carried out. This fiber is native to Andean regions and grows easily in wild or cultivated form in the valleys and hillsides of Colombia, Ecuador, and Peru. Fibers of "Furcraea andina" were characterized by experimental tests to determine their hydraulic conductivity or permeability and porosity in order to use this medium for bioremediation of contaminated aquifer exploiting the physical, chemical and microbial capacity of natural fiber in heavy metal adsorption. To evaluate empirically the hydraulic conductivity, laboratory tests were carried out at constant head specifically on the fibers manually extracted. For these tests we used a flow cell (used as permeameter), containing the "Furcraea andina" fibers to be characterized, suitably connected by a tygon pipe to a Marriott's bottle, which had a plastic tube that allow the adjustment of the hydraulic head for different tests to a constant value. By this experiment it was also possible to identify relationships that enable the estimation of permeability as a function of density, i.e. of the compaction degree of the fibers. Our study was carried out for three values of hydraulic head (H), namely 10, 18, and 25 cm and for each

  14. Permeâmetro de carga decrescente associado a programa computacional para a determinação da condutividade hidráulica do solo saturado Falling head permeameter and software to determine the hydraulic conductivity of saturated soil

    Paulo Ivonir Gubiani


    Full Text Available A condutividade hidráulica do solo saturado (Kθs é uma propriedade com grande variabilidade, o que exige a utilização de um número maior de determinações para que sua descrição possa ser feita adequadamente pela função densidade de probabilidade normal. Consequentemente, há aumento de trabalho e de tempo para a obtenção dos resultados, principalmente se as determinações forem feitas com equipamentos de pouca praticidade. A construção de equipamentos de maior praticidade e o desenvolvimento de ferramentas computacionais podem tornar o processo de análise mais rápido e preciso. Com esse objetivo, foi construído um permeâmetro de carga decrescente e desenvolvido um software para a aquisição de dados. As medidas de Kθs obtidas com esses equipamentos, em amostras de um Argissolo, mostraram menor variabilidade, avaliada pelo coeficiente de variação, o que resultou em maior precisão das determinações. Além disso, o tempo de análise foi reduzido em 30 %.The soil saturated hydraulic conductivity (Kθs is a property with great variability, which requires the use of a greater number of determinations so that they can be described by the normal probability density function. Consequently, there is an increase in time and labor to obtain Kθs results if determined by conventional equipment. The use of more practical equipment and computational tools allows a faster and more accurate analysis. With this aim a falling head permeameter was built and a software for data acquisition was developed. Values of Kθs obtained with this equipment in Hapludalf samples showed less variability, as assessed by the coefficient of variation, resulting in more precise measurements. Moreover, the time of analysis was reduced by 30 %.

  15. Gravity-Driven Hydraulic Fractures

    Germanovich, L. N.; Garagash, D.; Murdoch, L. C.; Robinowitz, M.


    This study is motived by a new method for disposing of nuclear waste by injecting it as a dense slurry into a hydraulic fracture that grows downward to great enough depth to permanently isolate the waste. Disposing of nuclear waste using gravity-driven hydraulic fractures is mechanically similar to the upward growth of dikes filled with low density magma. A fundamental question in both applications is how the injected fluid controls the propagation dynamics and fracture geometry (depth and breadth) in three dimensions. Analog experiments in gelatin [e.g., Heimpel and Olson, 1994; Taisne and Tait, 2009] show that fracture breadth (the short horizontal dimension) remains nearly stationary when the process in the fracture "head" (where breadth is controlled) is dominated by solid toughness, whereas viscous fluid dissipation is dominant in the fracture tail. We model propagation of the resulting gravity-driven (buoyant or sinking), finger-like fracture of stationary breadth with slowly varying opening along the crack length. The elastic response to fluid loading in a horizontal cross-section is local and can be treated similar to the classical Perkins-Kern-Nordgren (PKN) model of hydraulic fracturing. The propagation condition for a finger-like crack is based on balancing the global energy release rate due to a unit crack extension with the rock fracture toughness. It allows us to relate the net fluid pressure at the tip to the fracture breadth and rock toughness. Unlike the PKN fracture, where breadth is known a priori, the final breadth of a finger-like fracture is a result of processes in the fracture head. Because the head is much more open than the tail, viscous pressure drop in the head can be neglected leading to a 3D analog of Weertman's hydrostatic pulse. This requires relaxing the local elasticity assumption of the PKN model in the fracture head. As a result, we resolve the breadth, and then match the viscosity-dominated tail with the 3-D, toughness

  16. 考虑非线性因素的气缸盖刚强度分析与评估%Analysis and Evaluation of Strength and Stiffness for Cylinder Head Based on Non-linear Factors

    徐岩; 田小飞; 王艳霞


    The strength and deformation of cylinder head under different conditions were researched, the three-dimensional solid model of cylinder head-gasket-liner-block composites was built and finally mesh generation and simulation analysis were carried out. The non-linear factor of cylinder head and gasket contact, as well as that of gasket material, was taken into consideration in the calculatioa Based on the mechanical intensity calculation of normal conditions, the intensifying potentials of cylinder head were analyzed under the condition that the maximum cylinder pressure increased to 18 Mpa and 20 Mpa respectively. The stress distribution of largely concerned sites and the deformation of cylinder head fire surface were analyzed before and after strengthening.%对不同工况下气缸盖的强度和变形情况进行了研究,建立了气缸盖—气缸垫—气缸套—机体的组合体三堆实体模型,进行了网格划分及仿真分析.考虑了气缸盖与气缸垫之间接触非线性因素以及气缸垫的材料非线性因素对气缸盖刚强度的影响,在进行正常工况机械强度计算的基础上,缸内最高燃烧压力增加为18 MPa和20 MPa工况下,对气缸盖的强化潜力进行了对比分析,分析了强化前后工程中比较关注部位的应力分布以及气缸盖底板火力面的变形分布情况.


    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydraulic analysis for estimating flood stages for a flood insurance study. It...

  18. Hydraulic Hybrid Vehicles

    EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

  19. 修筑寒区小型水利工程的经验回顾%A Review of Experience in Constructing Low-head Hydraulic Projects in Permafrost Regions

    Rudolf V. Zhang


    The paper provides a review of experience with the construction of hydraulic projects in the permafrost regions. Principles for construction, operation and maintenance of earth dams are refined and formulated. High priority needs for improving the stability of structures are identified.

  20. On the Hydraulics of Flowing Horizontal Wells

    Bian, A.; Zhan, H.


    A flowing horizontal well is a special type of horizontal well that does not have pumping/injecting facility. The discharge rate of a flowing horizontal well is controlled by the hydraulic gradient between the aquifer and the well and it generally varies with time if the hydraulic head of the aquifer is transient. This type of well has been used in landslide control, mining dewatering, water table control, underground water transportation through a horizontal tunnel, agricultural water drainage, and other applications. Flowing horizontal wells have quite different hydrodynamic characteristics from horizontal wells with fixed pumping or injecting rates because their discharge rates are functions of the aquifer hydraulic heads (Zhan et al, 2001; Zhan and Zlotnik, 2002). Hydraulics of flowing horizontal wells have rarely been studied although the hydraulics of flowing vertical wells have been extensively investigated before. The purpose of this paper is to obtain analytical solutions of groundwater flow to a flowing horizontal-well in a confined aquifer, in a water table aquifer without precipitation, and in a water table aquifer with precipitation. The functions of the flowing horizontal well discharge rates versus time will be obtained under above mentioned different aquifer conditions. The relationships of the aquifer hydraulic heads versus the discharge rates of the well will be investigated. The rate of water table decline due to the dewatering of the well will also be computed, and this solution is particularly useful for landslide control and mining dewatering. The theoretical solutions will be compared with results of experiments that will be conducted in the hydrological laboratory at Texas A&M University. Reference: Zhan, H., Wang, L.V., and Park, E, On the horizontal well pumping tests in the anisotropic confined aquifers, J. hydrol., 252, 37-50, 2001. Zhan, H., and Zlotnik, V. A., Groundwater flow to a horizontal or slanted well in an unconfined aquifer

  1. Thermal Hydraulic Stability in a Coaxial Thermosyphon

    YANG Jianhui; LU Wenqiang; LI Qing; LI Qiang; ZHOU Yuan


    The heat transfer and thermal hydraulic stability in a two-phase thermosyphon with coaxial riser and down-comer has been experimentally investigated and theoretically analyzed to facilitate its application in cold neutron source. The flow in a coaxial thermosyphon was studied experimentally for a variety of heating rates, transfer tube lengths, charge capacities, and area ratios. A numerical analysis of the hydraulic balance between the driving pressure head and the resistance loss has also been performed. The results show that the presented coaxial thermosyphon has dynamic performance advantages relative to natural circulation in a boiling water reactor.

  2. Characteristics analysis for different water heads on the efficiency hill chart of Francis turbine

    Wang, Z. N.; Guo, P. C.; Luo, X. Q.; Wang, Y. L.; Sun, S. H.


    Based on the test results of Francis turbine, the causes and inevitability of various hydraulic phenomena in the model combined characteristic curve for typical water heads were analyzed in this paper. the difference of the model combined characteristic curve from the low water head to the high water head is compared, and the characteristics and commonness of the model combined characteristic curve about different water head are summarized. Further, hydraulic performance and geometric features of Francis turbine are revealed by particularly analyzing model combined characteristic curves, and to provide powerful theoretical basis and definite modification direction for the hydraulic design of hydraulic turbine.

  3. Spatial variability in streambed hydraulic conductivity of contrasting stream morphologies

    Sebök, Éva; Calvache, Carlos Duque; Engesgaard, Peter Knudegaard;


    Streambed hydraulic conductivity is one of the main factors controlling variability in surface water-groundwater interactions, but only few studies aim at quantifying its spatial and temporal variability in different stream morphologies. Streambed horizontal hydraulic conductivities (Kh) were...... therefore determined from in-stream slug tests, vertical hydraulic conductivities (Kv) were calculated with in-stream permeameter tests and hydraulic heads were measured to obtain vertical head gradients at eight transects, each comprising five test locations, in a groundwater-dominated stream. Seasonal...... small-scale measurements were taken in December 2011 and August 2012, both in a straight stream channel with homogeneous elevation and downstream of a channel meander with heterogeneous elevation. All streambed attributes showed large spatial variability. Kh values were the highest at the depositional...

  4. Thermally Actuated Hydraulic Pumps

    Jones, Jack; Ross, Ronald; Chao, Yi


    Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

  5. Hydraulic Conductivity Anisotropy of Heterogeneous Unsaturated Soils

    Sun, Dongmin; Zhu, Jianting


    The effects of saturation degree (or capillary pressure) on hydraulic conductivity anisotropy in unsaturated soils have not been fully understood. This study developed an approach based on a conceptualization of combining the neural network based pedo-transfer function (PTF) results with the thin layer concept to explore the capillary pressure-dependent anisotropy in relation to soil texture and soil bulk density. The main objective is to examine how anisotropy characteristics are related to the relationships between hydraulic parameters and the basic soil attributes such as texture and bulk density. The hydraulic parameters are correlated with the texture and bulk density based on the pedo-transfer function (PTF) results. It is demonstrated that non-monotonic behavior of the unsaturated soil anisotropy in relation to the capillary pressure is only observed when the saturated hydraulic conductivity and the shape parameter are both related to the mean particle diameter. When only one hydraulic parameter is related to the grain diameter or when both are not related to the same attribute simultaneously, the unsaturated soil anisotropy increases monotonically with the increasing capillary pressure head. Therefore, it is suggested that this behavior is mainly due to the coupled dependence of the layer saturated hydraulic conductivities and the shape factors on the texture and bulk density. The correlation between the soil grain diameter and bulk density decreases the anisotropy effects of the unsaturated layered soils. The study illustrates that the inter-relationships of soil texture, bulk density, and hydraulic properties may cause vastly different characteristics of anisotropic unsaturated soils.

  6. Vibration of hydraulic machinery

    Wu, Yulin; Liu, Shuhong; Dou, Hua-Shu; Qian, Zhongdong


    Vibration of Hydraulic Machinery deals with the vibration problem which has significant influence on the safety and reliable operation of hydraulic machinery. It provides new achievements and the latest developments in these areas, even in the basic areas of this subject. The present book covers the fundamentals of mechanical vibration and rotordynamics as well as their main numerical models and analysis methods for the vibration prediction. The mechanical and hydraulic excitations to the vibration are analyzed, and the pressure fluctuations induced by the unsteady turbulent flow is predicted in order to obtain the unsteady loads. This book also discusses the loads, constraint conditions and the elastic and damping characters of the mechanical system, the structure dynamic analysis, the rotor dynamic analysis and the system instability of hydraulic machines, including the illustration of monitoring system for the instability and the vibration in hydraulic units. All the problems are necessary for vibration pr...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... or potentially pose a risk, depending on their nature and the strength of the MRI magnet. Many ... is positioned around the head. If a contrast material will be used in the MRI exam, a ...

  8. Handbook of hydraulic fluid technology

    Totten, George E


    ""The Handbook of Hydraulic Fluid Technology"" serves as the foremost resource for designing hydraulic systems and for selecting hydraulic fluids used in engineering applications. Featuring new illustrations, data tables, as well as practical examples, this second edition is updated with essential information on the latest hydraulic fluids and testing methods. The detailed text facilitates unparalleled understanding of the total hydraulic system, including important hardware, fluid properties, and hydraulic lubricants. Written by worldwide experts, the book also offers a rigorous overview of h

  9. Head pulsations in a centrifugal pump

    Boiko, V. S.; Sotnyk, M. I.; Moskalenko, V. V.


    This article investigated the factors, which affect to the character of the head pulsations of a centrifugal pump. We investigated the dependence of the shape and depth of these pulsations from the operation mode of the pump. Was determined, that the head pulsations at the outlet of the impeller (pulsations on the blade passing frequency) cause head pulsations at the outlet of the pump, that have the same frequency, but differ in shape and depth. These pulsations depend on the design features of the flow-through part of the pump (from the ratio of hydraulic losses on the friction and losses on the vortex formation). A feature of the researches that were conducted is also the using of not only hydraulic but also electric modeling methods. It allows determining the values of the components of hydraulic losses.

  10. The influence of hydraulic forces on the selection of structural form

    Glerum, A.; Schippers, J.


    Besides that the hydraulic forces have an influence on the structure, the shape of the structure may often influence the hydraulic loads as well. A distinction should be made between hydrostatic forces which are for instance caused by a difference in head between two water levels and dynamic forces

  11. Root water extraction and limiting soil hydraulic conditions estimated by numerical simulation

    Jong van Lier, de Q.; Metselaar, K.; Dam, van J.C.


    Root density, soil hydraulic functions, and hydraulic head gradients play an important role in the determination of transpiration-rate-limiting soil water contents. We developed an implicit numerical root water extraction model to solve the Richards equation for the modeling of radial root water

  12. FEMA DFIRM Hydraulic Structures

    Minnesota Department of Natural Resources — This layer and accompanying attribute table is required whenever hydraulic structures are shown in the flood profile. It is also required if levees are shown on the...

  13. Water Hydraulic Systems

    Conrad, Finn


    The paper presents research results using IT-Tools for CAD and dynamic modelling, simulation, analysis, and design of water hydraulic actuators for motion control of machines, lifts, cranes and robots. Matlab/Simulink and CATIA are used as IT-Tools. The contributions include results from on......-going research projects on fluid power and mechatronics based on tap water hydraulic servovalves and linear servo actuators and rotary vane actuators for motion control and power transmission. Development and design a novel water hydraulic rotary vane actuator for robot manipulators. Proposed mathematical...... modelling, control and simulation of a water hydraulic rotary vane actuator applied to power and control a two-links manipulator and evaluate performance. The results include engineering design and test of the proposed simulation models compared with IHA Tampere University’s presentation of research...

  14. Constant-Pressure Hydraulic Pump

    Galloway, C. W.


    Constant output pressure in gas-driven hydraulic pump would be assured in new design for gas-to-hydraulic power converter. With a force-multiplying ring attached to gas piston, expanding gas would apply constant force on hydraulic piston even though gas pressure drops. As a result, pressure of hydraulic fluid remains steady, and power output of the pump does not vary.

  15. Trend of hydraulic units

    Deshimaru, Jun' ichi


    The gear, vane and piston pumps occupy a more then 90% share in the hydraulic pumps. Comparatively large pumps are mainly variable delivery piston pumps. The piston pumps are comparatively high in output density (output per unit weight), indicating the hydraulic pump in performance, and tend to become higher and higher in it. Though they are mainly 210 to 350kgf/cm/sup 2/ in rated pressure, some of them come to surpass 400kgf/cm/sup 3/ in it. While the progress in computation also requires the high speed operation, high accuracy and other severe conditions for the hydraulic units, which accordingly and increasingly intensify the requirement for hydraulic oil in abrasion resistibility, oxidation stability and response characteristics. While cavitation comes to easily occur, which considerably and disadvantageously influences hydraulic oil in life through degradation, noise level and respondingness. From now on, the development of high performance oil and study of mechanical structure are important. 19 references, 9 figures, 2 tables.

  16. Cavitation in Hydraulic Machinery

    Kjeldsen, M.


    The main purpose of this doctoral thesis on cavitation in hydraulic machinery is to change focus towards the coupling of non-stationary flow phenomena and cavitation. It is argued that, in addition to turbulence, superimposed sound pressure fluctuations can have a major impact on cavitation and lead to particularly severe erosion. For the design of hydraulic devices this finding may indicate how to further limit the cavitation problems. Chapter 1 reviews cavitation in general in the context of hydraulic machinery, emphasizing the initial cavitation event and the role of the water quality. Chapter 2 discusses the existence of pressure fluctuations for situations common in such machinery. Chapter 3 on cavitation dynamics presents an algorithm for calculating the nucleation of a cavity cluster. Chapter 4 describes the equipment used in this work. 53 refs., 55 figs.,10 tabs.

  17. Hydraulics and pneumatics

    Parr, Andrew


    Nearly all industrial processes require objects to be moved, manipulated or subjected to some sort of force. This is frequently accomplished by means of electrical equipment (such as motors or solenoids), or via devices driven by air (pneumatics) or liquids (hydraulics).This book has been written by a process control engineer as a guide to the operation of hydraulic and pneumatic systems for all engineers and technicians who wish to have an insight into the components and operation of such a system.This second edition has been fully updated to include all recent developments su

  18. Popeye Project: Hydraulic umbilical

    Jordan, K.G.; Williams, V.T.


    For the Popeye Project, the longest super-duplex hydraulic umbilical in the world was installed in the Gulf of Mexico. This paper reports on its selection and project implementation. Material selection addresses corrosion in seawater, water-based hydraulic fluid, and methanol. Five alternatives were considered: (1) carbon-steel with traditional coating and anodes, (2) carbon-steel coated with thermally sprayed aluminum, (3) carbon-steel sheathed in aluminum, (4) super-duplex, and (5) titanium. The merits and risks associated with each alternative are discussed. The manufacture and installation of the selected umbilical are also reported.

  19. Hydraulic Arm Modeling via Matlab SimHydraulics

    Věchet, Stanislav; Krejsa, Jiří


    System modeling is a vital tool for cost reduction and design process speed up in most engineering fields. The paper is focused on modeling of hydraulic arm as a part of intelligent prosthesis project, in the form of 2DOF open kinematic chain. The arm model combines mechanical, hydraulic and electric subsystems and uses Matlab as modeling tool. SimMechanics Matlab extension is used for mechanical part modeling, SimHydraulics toolbox is used for modeling of hydraulic circuit used for actuating...

  20. An evaluation of a hubless inducer and a full flow hydraulic turbine driven inducer boost pump

    Lindley, B. K.; Martinson, A. R.


    The purpose of the study was to compare the performance of several configurations of hubless inducers with a hydrodynamically similar conventional inducer and to demonstrate the performance of a full flow hydraulic turbine driven inducer boost pump using these inducers. A boost pump of this type consists of an inducer connected to a hydraulic turbine with a high speed rotor located in between. All the flow passes through the inducer, rotor, and hydraulic turbine, then into the main pump. The rotor, which is attached to the main pump shaft, provides the input power to drive the hydraulic turbine which, in turn, drives the inducer. The inducer, rotating at a lower speed, develops the necessary head to prevent rotor cavitation. The rotor speed is consistent with present main engine liquid hydrogen pump designs and the overall boost pump head rise is sufficient to provide adequate main pump suction head. This system would have the potential for operating at lower liquid hydrogen tank pressures.


    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydraulic procedures for estimating flood discharges for a flood insurance...

  2. Stress and Deformation Analysis of Cylinder-Crown Integrated Hydraulic Press with Large Capacity

    Weiwei Zhang; Xiaosong Wang; Zhongren Wang


    Cylinder⁃crown integrated hydraulic press ( CCIHP ) is a new press structure. The hemispherical hydraulic cylinder also functions as a main portion of crown, which has lower weight and higher section modulus compared with the conventional hydraulic cylinder and press crown. In order to design cylinder⁃crown integrated hydraulic press with large capacity, the theoretical design of hemispherical hydraulic cylinder was first proposed, and the structural parameters of 150 MN CCIHP were listed. Then the simulation was carried out to analyze the stress and deformation of CCIHP , and weight comparison was conducted between CCIHP and conventional press. It is shown that the weight reduction for hydraulic cylinder and press crown is about 20%compared with that for conventional press, and the stress and deformation are both within the range of constraints including strength and stiffness conditions. It is possible to manufacture cylinder⁃crown integrated hydraulic press with large capacity.

  3. Hydraulic hoist-press

    Babayev, Z.B.; Abashev, Z.V.


    The efficiency expert of the Angrenskiy production-technological administration of the production association Sredazugol A. V. Bubnov has suggested a hydraulic hoist-press for repairing road equipment which is a device consisting of lifting mechanism, press and test stand for verifying the high pressure hoses and pumps.

  4. Modelling of Hydraulic Robot

    Madsen, Henrik; Zhou, Jianjun; Hansen, Lars Henrik


    This paper describes a case study of identifying the physical model (or the grey box model) of a hydraulic test robot. The obtained model is intended to provide a basis for model-based control of the robot. The physical model is formulated in continuous time and is derived by application...

  5. Water Hydraulic Systems

    Conrad, Finn


    The paper presents research results using IT-Tools for CAD and dynamic modelling, simulation, analysis, and design of water hydraulic actuators for motion control of machines, lifts, cranes and robots. Matlab/Simulink and CATIA are used as IT-Tools. The contributions include results from on-going...

  6. Effects of model layer simplification using composite hydraulic properties

    Sepulveda, Nicasio; Kuniansky, Eve L.


    The effects of simplifying hydraulic property layering within an unconfined aquifer and the underlying confining unit were assessed. The hydraulic properties of lithologic units within the unconfined aquifer and confining unit were computed by analyzing the aquifer-test data using radial, axisymmetric two-dimensional (2D) flow. Time-varying recharge to the unconfined aquifer and pumping from the confined Upper Floridan aquifer (USA) were simulated using 3D flow. Conceptual flow models were developed by gradually reducing the number of lithologic units in the unconfined aquifer and confining unit by calculating composite hydraulic properties for the simplified lithologic units. Composite hydraulic properties were calculated using either thickness-weighted averages or inverse modeling using regression-based parameter estimation. No significant residuals were simulated when all lithologic units comprising the unconfined aquifer were simulated as one layer. The largest residuals occurred when the unconfined aquifer and confining unit were aggregated into a single layer (quasi-3D), with residuals over 100% for the leakage rates to the confined aquifer and the heads in the confining unit. Residuals increased with contrasts in vertical hydraulic conductivity between the unconfined aquifer and confining unit. Residuals increased when the constant-head boundary at the bottom of the Upper Floridan aquifer was replaced with a no-flow boundary.

  7. Mechanization of hydraulic testing of chemical equipment

    Bannikov, M.T.; Fridman, R.N.; Petrovnin, A.I.


    The Institute VNIIPTKhimmash has worked out a comprehensive list of equipment for testing for strength and tightness containers and heat exchangers with jackets, with mixers, also of individual parts and subassemblies for this equipment. Points out that in the test stands developed for hydraulic testing of vessels both individual and centralized recirculating water supply can be used. Concludes that a reduction in labor consumption in hydraulic testing and in servicing of all the equipment used, an increase in the mechanization of this kind of chemical equipment, and the solution of the problem of standardization not only with regard to dimensions and parameters, but also with regard to the makes and types of the materials used, will make possible a considerable increase in labor productivity and product quality.

  8. Performance and model of a novel multi-sparger multi-stage airlift loop membrane bioreactor to treat high-strength 7-ACA pharmaceutical wastewater: effect of hydraulic retention time, temperature and pH.

    Chen, Zhao-bo; He, Zhang-wei; Tang, Cong-cong; Hu, Dong-xue; Cui, Yu-bo; Wang, Ai-jie; Zhang, Ying; Yan, Li-long; Ren, Nan-qi


    In this study, three novel multi-sparger multi-stage airlift loop membrane bioreactors (Ms(2)ALMBRs) were set up in parallel for treating synthetic high-strength 7-ACA pharmaceutical wastewater under different HRTs, temperatures and pHs, respectively. During the 200-day operating time, average COD removal efficiencies were 94.96%, 96.05% and 93.9%. While average 7-ACA removal efficiencies were 66.44%, 59.04% and 59.60%, respectively. The optimal conditions were 10h, 15-35°C and 7-9 for HRT, temperature and pH, respectively. Moreover, the sludge characteristics and microorganism drug-resistances were explored. Results showed that different temperatures and pHs influenced contaminant removals by affecting MLSS concentration and β-lactamase activity significantly. In addition, mathematical statistical models, built on the polynomial and linear regression techniques, were developed for exploring the inner relationships between HRT, temperature and pH changes and MLSS concentrations, β-lactamase activities and contaminant removals of the Ms(2)ALMBR system.

  9. Hydraulic manipulator research at ORNL

    Kress, R.L.; Jansen, J.F. [Oak Ridge National Lab., TN (United States); Love, L.J. [Oak Ridge Inst. for Science and Education, TN (United States)


    Recently, task requirements have dictated that manipulator payload capacity increase to accommodate greater payloads, greater manipulator length, and larger environmental interaction forces. General tasks such as waste storage tank cleanup and facility dismantlement and decommissioning require manipulator life capacities in the range of hundreds of pounds rather than tens of pounds. To meet the increased payload capacities demanded by present-day tasks, manipulator designers have turned once again to hydraulics as a means of actuation. In order to successfully design, build, and deploy a new hydraulic manipulator (or subsystem), sophisticated modeling, analysis, and control experiments are usually needed. Oak Ridge National Laboratory (ORNL) has a history of projects that incorporate hydraulics technology, including mobile robots, teleoperated manipulators, and full-scale construction equipment. In addition, to support the development and deployment of new hydraulic manipulators, ORNL has outfitted a significant experimental laboratory and has developed the software capability for research into hydraulic manipulators, hydraulic actuators, hydraulic systems, modeling of hydraulic systems, and hydraulic controls. The purpose of this article is to describe the past hydraulic manipulator developments and current hydraulic manipulator research capabilities at ORNL. Included are example experimental results from ORNL`s flexible/prismatic test stand.


    WANG Fu-jun; LI Xiao-qin; MA Jia-mei; YANG Min; ZHU Yu-liang


    The features of unsteady flow such as pressure variation and fluctuation in a large hydraulic turbine usually lead to the instability of operation.This article reports the recent in site investigation concerning the characteristic frequencies in pressure fluctuation,shaft torsional oscillation and structural vibration of a prototype 700 MW Francis turbine unit.The investigation was carried out for a wide load range of 200 MW-700 MW in the condition of water head 57 m-90 m.An extensive analysis of both time-history and frequency data of these unsteady hydraulic behaviours was conducted.It was observed that the pressure fluctuation in a draft tube is stronger than that in upstream flow passage.The low frequency with about one third of rotation frequency is dominative for the pressure fluctuation in part load range.Also the unsteady features of vibration of head cover and torsional oscillation of shaft exhibited the similar features.Numerical analysis showed that the vibration and oscillation are caused by vortex rope in the draft tube.In addition,a strong vibration with special characteristic frequency was observed for the head cover in middle load range.The pressure fluctuation in the draft tube with the same frequency was also recorded.Because this special vibration has appeared in the designed normal running condition,it should be avoided by carefully allocating power load in the future operation.

  11. Remotely Adjustable Hydraulic Pump

    Kouns, H. H.; Gardner, L. D.


    Outlet pressure adjusted to match varying loads. Electrohydraulic servo has positioned sleeve in leftmost position, adjusting outlet pressure to maximum value. Sleeve in equilibrium position, with control land covering control port. For lowest pressure setting, sleeve shifted toward right by increased pressure on sleeve shoulder from servovalve. Pump used in aircraft and robots, where hydraulic actuators repeatedly turned on and off, changing pump load frequently and over wide range.

  12. Undular Hydraulic Jump

    Oscar Castro-Orgaz


    Full Text Available The transition from subcritical to supercritical flow when the inflow Froude number Fo is close to unity appears in the form of steady state waves called undular hydraulic jump. The characterization of the undular hydraulic jump is complex due to the existence of a non-hydrostatic pressure distribution that invalidates the gradually-varied flow theory, and supercritical shock waves. The objective of this work is to present a mathematical model for the undular hydraulic jump obtained from an approximate integration of the Reynolds equations for turbulent flow assuming that the Reynolds number R is high. Simple analytical solutions are presented to reveal the physics of the theory, and a numerical model is used to integrate the complete equations. The limit of application of the theory is discussed using a wave breaking condition for the inception of a surface roller. The validity of the mathematical predictions is critically assessed using physical data, thereby revealing aspects on which more research is needed

  13. Head Injuries

    ... object that's stuck in the wound. previous continue Concussions Concussions — the temporary loss of normal brain function due ... also a type of internal head injury. Repeated concussions can permanently damage the brain. In many cases, ...

  14. Head Tilt

    ... Healthy Living Healthy Living Healthy Living Nutrition Fitness Sports Oral Health Emotional Wellness Growing Healthy Sleep Safety & ... When this happens, the neck muscles go into spasm, causing the head to tilt to one side. ...

  15. Head Injuries

    ... ATV) Safety Balance Disorders Knowing Your Child's Medical History First Aid: Falls First Aid: Head Injuries Preventing Children's Sports Injuries Getting Help: Know the Numbers Concussions Stay Safe: Baseball Concussions Concussions: Getting Better Sports and Concussions Dealing ...

  16. Head MRI

    ... heart valves Heart defibrillator or pacemaker Inner ear (cochlear) implants Kidney disease or dialysis (you may not ... to: Abnormal blood vessels in the brain ( arteriovenous malformations of the head ) Tumor of the nerve that ...


    O. M. Pshinko


    Full Text Available Purpose. Scientific work aims at the development and testing of information system to meet the challenges of concrete composition design and control (for railway structures and buildings based on the physico-analytical method algorithm for hydraulic concrete composition calculation. Methodology. The proposed algorithm of hydraulic concrete composition calculation is based on the physicochemical mechanics and in particular on the rheology of elastic–viscous–plastic bodies. The system of canonical equations consists of the equations for concrete strength, absolute volume, concrete mix consistency as well as the equation for optimal concrete saturation with aggregates while minimizing cement content. The joint solution of these four equations related to composition allows determining for the materials the concrete composition of required strength, concrete workability with minimum cement content. The procedure for calculation of hydraulic concrete composition according to the physico-analytical method consists of two parts: 1 physical, which is laboratory testing of concrete mix components in different concrete compositions; 2 analytical, which represents the calculation algorithm for concrete compositions equivalent in concrete strength and workability that comply with the specific conditions of concrete placing. Findings. To solve the problem of designing the concrete composition with the desired properties for railway structures and buildings it was proposed to use the information technology in the form of a developed computer program whose algorithm includes the physico-analytical method for hydraulic concrete composition determination. Originality. The developed concrete composition design method takes into account the basic properties of raw materials, concrete mix and concrete, which are pre-determined. The distinctive feature of physico-analytical method is obtaining of a set of equivalent compositions with a certain concrete mix

  18. Hydraulic System Design of Hydraulic Actuators for Large Butterfly Valves

    HUANG, Ye; Liu, Changsheng; Shiongur Bamed


    Hydraulic control systems of butterfly valves are presently valve-controlled and pump-controlled. Valve-controlled hydraulic systems have serious power loss and generate much heat during throttling. Pump-controlled hydraulic systems have no overflow or throttling losses but are limited in the speed adjustment of the variable-displacement pump, generate much noise, pollute the environment, and have motor power that does not match load requirements, resulting in low efficiency under...

  19. Hydraulic System Design of Hydraulic Actuators for Large Butterfly Valves

    Ye HUANG


    Full Text Available Hydraulic control systems of butterfly valves are presently valve-controlled and pump-controlled. Valve-controlled hydraulic systems have serious power loss and generate much heat during throttling. Pump-controlled hydraulic systems have no overflow or throttling losses but are limited in the speed adjustment of the variable-displacement pump, generate much noise, pollute the environment, and have motor power that does not match load requirements, resulting in low efficiency under light loads and wearing of the variable-displacement pump. To overcome these shortcomings, this article designs a closed hydraulic control system in which an AC servo motor drives a quantitative pump that controls a spiral swinging hydraulic cylinder, and analyzes and calculates the structure and parameters of a spiral swinging hydraulic cylinder. The hydraulic system adjusts the servo motor’s speed according to the requirements of the control system, and the motor power matches the power provided to components, thus eliminating the throttling loss of hydraulic circuits. The system is compact, produces a large output force, provides stable transmission, has a quick response, and is suitable as a hydraulic control system of a large butterfly valve.

  20. Predicting saturated hydraulic conductivity using soil morphological properties

    Gülay Karahan


    Full Text Available Many studies have been conducted to predict soil saturated hydraulic conductivity (Ks by parametric soil properties such as bulk density and particle-size distribution. Although soil morphological properties have a strong effect on Ks, studies predicting Ks by soil morphological properties such as type, size, and strength of soil structure; type, orientation and quantity of soil pores and roots and consistency are rare. This study aimed at evaluating soil morphological properties to predict Ks. Undisturbed soil samples (15 cm length and 8.0 cm id. were collected from topsoil (0-15 cm and subsoil (15-30 cm (120 samples with a tractor operated soil sampler at sixty randomly selected sampling sites on a paddy field and an adjecent grassland in Central Anatolia (Cankırı, Turkey. Synchronized disturbed soil samples were taken from the same sampling sites and sampling depths for basic soil analyses. Saturated hydraulic conductivity was measured on the soil columns using a constant-head permeameter. Following the Ks measurements, the upper part of soil columns were covered to prevent evaporation and colums were left to drain in the laboratory. When the water flow through the column was stopped, a subsample were taken for bulk density and then soil columns were disturbed for describing the soil morphological properties. In addition, soil texture, bulk density, pH, field capacity, wilting point, cation exchange capacity, specific surface area, aggregate stability, organic matter, and calcium carbonate were measured on the synchronized disturbed soil samples. The data were divided into training (80 data values and validation (40 data values sets. Measured values of Ks ranged from 0.0036 to 2.14 cmh-1 with a mean of 0.86 cmh-1. The Ks was predicted from the soil morphological and parametric properties by stepwise multiple linear regression analysis. Soil structure class, stickiness, pore-size, root-size, and pore-quantity contributed to the Ks prediction

  1. Safety estimation of high-pressure hydraulic cylinder using FSI method

    KIM J.H.; HAN S.M.; KIM Y.J.


    Hydraulic cylinder is a primary component of the hydraulic valve systems.The numerical study of hydraulic cylinder to evaluate the stress analysis,the life assessment and the performance of operation characteristics in hydraulic cylinder were described.The calculation of safety factor,fatigue life,piston chamber pressure,rod chamber pressure and the change of velocity of piston with flow time after the beginning of hydraulic cylinder were incorporated.Numerical analysis was performed using the commercial CFD code,ANSYS with unsteady,dynamic mesh model,two-way FSI (fluid-struc-ture interaction)method and k-εturbulent model.The internal pressure in hydraulic cylinder through stress analysis show higher than those of the yield strength.

  2. Modelling of Hydraulic Robot

    Madsen, Henrik; Zhou, Jianjun; Hansen, Lars Henrik


    This paper describes a case study of identifying the physical model (or the grey box model) of a hydraulic test robot. The obtained model is intended to provide a basis for model-based control of the robot. The physical model is formulated in continuous time and is derived by application...... of the laws of physics on the system. The unknown (or uncertain) parameters are estimated with Maximum Likelihood (ML) parameter estimation. The identified model has been evaluated by comparing the measurements with simulation of the model. The identified model was much more capable of describing the dynamics...... of the system than the deterministic model....

  3. Hydraulic mining method

    Huffman, Lester H.; Knoke, Gerald S.


    A method of hydraulically mining an underground pitched mineral vein comprising drilling a vertical borehole through the earth's lithosphere into the vein and drilling a slant borehole along the footwall of the vein to intersect the vertical borehole. Material is removed from the mineral vein by directing a high pressure water jet thereagainst. The resulting slurry of mineral fragments and water flows along the slant borehole into the lower end of the vertical borehole from where it is pumped upwardly through the vertical borehole to the surface.

  4. Spinning hydraulic jump

    Abderrahmane, Hamid; Kasimov, Aslan


    We report an experimental observation of a new symmetry breaking of circular hydraulic jump into a self-organized structure that consists of a spinning polygonal jump and logarithmic-spiral waves of fluid elevation downstream. The waves are strikingly similar to spiral density waves in galaxies. The fluid flow exhibits counterparts of salient morphological features of galactic flows, in particular the outflow from the center, jets, circum-nuclear rings, gas inflows toward the galactic center, and vortices. The hydrodynamic instability revealed here may have a counterpart that plays a role in the formation and sustainability of spiral arms in galaxies.

  5. 46 CFR 28.880 - Hydraulic equipment.


    ... hydraulic equipment and the adjacent work area. Protection shall be afforded to the operator of hydraulic... 46 Shipping 1 2010-10-01 2010-10-01 false Hydraulic equipment. 28.880 Section 28.880 Shipping... INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.880 Hydraulic equipment. (a) Each hydraulic system must...

  6. Tidal modulation of two-layer hydraulic exchange flows

    L. M. Frankcombe


    Full Text Available Time-dependent, two layer hydraulic exchange flow is studied using an idealised shallow water model. It is found that barotropic time-dependent perturbations, representing tidal forcing, increase the baroclinic exchange flux above the steady hydraulic limit, with flux increasing monotonically with tidal amplitude (measured either by height or flux amplitude over a tidal period. Exchange flux also depends on the non-dimensional tidal period, γ, which was introduced by Helfrich (1995. Resonance complicates the relationship between exchange flux and height amplitude, but, when tidal strength is characterised by flux amplitude, exchange flux is a monotonic function of γ.


    Piyavskiy Semen Avraamovich


    Full Text Available The article covers the use of geosynthetic casings in hydraulic engineering. The authors describe the structure of earth dams that have geosynthetic casings used as the reinforcement of downstream slopes. Results of stability calculations are provided. The authors consider several examples of effective application of advanced geosynthetic materials used in combination with local building materials as structural elements of hydraulic engineering facilities. Their analysis has demonstrated a strong potential and expediency of application of geosynthetic casings in the course of construction and renovation of low-pressure earth dams. The authors have also developed a new structure of an earth dam. The new earth dam has geosynthetic casings used as structural reinforcing elements of the crown and the downstream slope. The dam structure contemplates the overflow of high water. The structural strengths of the proposed solution include a smaller material consumption rate, lower labour intensiveness and cost of the slope reinforcement due to the application of local building materials used to fill the casings, fast and easy depositing of slope reinforcing elements, and high workability of its dismantling for repair purposes. The authors have also completed the analysis of stability of geosynthetic casings of downstream slopes of an earth dam. The analysis has proven high efficiency of a small slope ratio in combination with its anchorage and reinforcement of the downstream toe with the help of high-strength geogrids.

  8. Applied hydraulic transients

    Chaudhry, M Hanif


    This book covers hydraulic transients in a comprehensive and systematic manner from introduction to advanced level and presents various methods of analysis for computer solution. The field of application of the book is very broad and diverse and covers areas such as hydroelectric projects, pumped storage schemes, water-supply systems, cooling-water systems, oil pipelines and industrial piping systems. Strong emphasis is given to practical applications, including several case studies, problems of applied nature, and design criteria. This will help design engineers and introduce students to real-life projects. This book also: ·         Presents modern methods of analysis suitable for computer analysis, such as the method of characteristics, explicit and implicit finite-difference methods and matrix methods ·         Includes case studies of actual projects ·         Provides extensive and complete treatment of governed hydraulic turbines ·         Presents design charts, desi...

  9. Hydraulic Conductivity of Residual Soil-Cement Mix

    Govindasamy, P.; Taha, M. R.


    In Malaysia, although there are several researches on engineering properties of residual soils, however study on the hydraulic conductivity properties of metasedimentary residual soils is still lacking. Construction of containment walls like slurry wall techniques can be achieved with hydraulic conductivity of approximately 5 x 10-7cm/sec. The objectives of the study were to determine the physical properties of metasedimentary residual soils and to determine the influence of 1%, 3%, 5% and 10% of cement on hydraulic conductivity parameters. The coefficient of hydraulic conductivity of the soil naturally and soil-cement mixtures were determined by using the falling head test. According to the test, the hydraulic conductivity of the original soil was 4.16 x 10-8 m/s. The value decreases to 3.89 x 10-8 m/s, 2.78 x 10-8 m/s then 6.83 x 10-9 m/s with the addition of 1%, 3% and 5% of cement additives, respectively. During the hydration process, cement hydrates is formed followed by the increase in pH value and Ca(OH)2 which will alter the modification of pores size and distribution. When the quantity of cement increases, the pores size decrease. But, the addition of 10% cement gives an increased hydraulic conductivity value to 2.78 x 10-8 m/s. With 10%, the pore size increase might due to flocculation and agglomeration reaction. The generated hydraulic conductivity values will indirectly become a guide in the preliminary soil cement stabilization to modify the properties of the soil to become more like the properties of a soft rock.1. Introduction

  10. Head Start.

    Greenman, Geri


    Discusses an art project in which students created drawings of mop heads. Explains that the approach of drawing was more important than the subject. States that the students used the chiaroscuro technique, used by Rembrandt and Caravaggio, in which light appears out of the darkness. (CMK)

  11. Numerical modeling of the effect of variation of boundary conditions on vadose zone hydraulic properties

    Tairone Paiva Leão


    Full Text Available An accurate estimation of hydraulic fluxes in the vadose zone is essential for the prediction of water, nutrient and contaminant transport in natural systems. The objective of this study was to simulate the effect of variation of boundary conditions on the estimation of hydraulic properties (i.e. water content, effective unsaturated hydraulic conductivity and hydraulic flux in a one-dimensional unsaturated flow model domain. Unsaturated one-dimensional vertical water flow was simulated in a pure phase clay loam profile and in clay loam interlayered with silt loam distributed according to the third iteration of the Cantor Bar fractal object Simulations were performed using the numerical model Hydrus 1D. The upper and lower pressure heads were varied around average values of -55 cm for the near-saturation range. This resulted in combinations for the upper and lower constant head boundary conditions, respectively, of -50 and -60 cm, -40 and -70 cm, -30 and -80 cm, -20 and -90 cm, and -10 and -100 cm. For the drier range the average head between the upper and lower boundary conditions was set to -550 cm, resulting in the combinations -500 and -600 cm, -400 and -700 cm, -300 and -800 cm, -200 and -900 cm, and -100 and -1,000 cm, for upper and lower boundary conditions, respectively. There was an increase in water contents, fluxes and hydraulic conductivities with the increase in head difference between boundary conditions. Variation in boundary conditions in the pure phase and interlayered one-dimensional profiles caused significant deviations in fluxes, water contents and hydraulic conductivities compared to the simplest case (a head difference between the upper and lower constant head boundaries of 10 cm in the wetter range and 100 cm in the drier range.

  12. The helical turbine: A new idea for low-head hydro

    Gorlov, A.M. [Northeastern Univ., Boston, MA (United States)


    Substantial potential exists at small hydro sites where heads are too low for conventional hydraulic turbines. A spiral-bladed turbine may offer a new alternative for tapping that potential in a cost-efficient manner.


    Huang Guan-hua; Zhang Ren-duo


    Stochastic approaches are useful to quantitatively describe transport behavior over large temporal and spatial scales while accounting for the influence of small-scale variabilities. Numerous solutions have been developed for unsaturated soil water flow based on the lognormal distribution of soil hydraulic conductivity. To our knowledge, no available stochastic solutions for unsaturated flow have been derived on the basis of the normal distribution of hydraulic conductivity. In this paper, stochastic solutions were developed for unsaturated flow by assuming the normal distribution of saturated hydraulic conductivity (Ks). Under the assumption that soil hydraulic properties are second-order stationary, analytical expressions for capillary tension head variance (σ2h) and effective hydraulic conductivity (K*ii) in stratified soils were derived using the perturbation method. The dependence of σ2h and K*ii on soil variability and mean flow variables (the mean capillary tension head and its temporal and spatial gradients) and mean flow conditions (wetting and drying) were systematically analyzed. The calculated variance of capillary tension head with the analytical solution derived in this paper was compared with field experimental data. The good agreement indicates that the analytical solution is applicable to evaluate the variance of capillary tension head of field soils with moderate variability.

  14. Hydraulic rams; a comparative investigation

    Tacke, J.H.P.M.


    A mathematical model describing the essential features of hydraulic ram operation is developed in order to clarify the possibilities and limitations of the ram relative to its site and its adjustments. The model distinguishes three different periods in the pumping cycle of the hydraulic ram: acceler

  15. Hydraulics. FOS: Fundamentals of Service.

    John Deere Co., Moline, IL.

    This manual on hydraulics is one of a series of power mechanics texts and visual aids for training in the servicing of agricultural and industrial machinery. Focus is on oil hydraulics. Materials provide basic information and illustrations for use by vocational students and teachers as well as shop servicemen and laymen. The twelve chapters focus…

  16. Hydraulic Stability of Accropode Armour

    Jensen, T.; Burcharth, H. F.; Frigaard, Peter

    , and to assess the influence of core permeability on the hydraulic stability of Accropodes. Two structures were examined, one with a relatively permeable core and one with a relatively impermeable core. In November/December 1995, Ph.D.-student Marten Christensen carried out the model tests on the structure...... with permeable core (crushed granite with a gradation of 5-8 mm). The outcome of this study is described in "Hydraulic Stability of Single-Layer Dolos and Accropode Armour Layers" by Christensen & Burcharth (1995). In January/February 1996, Research Assistant Thomas Jensen carried out a similar study......The present report describes the hydraulic model tests of Accropode armour layers carried out at the Hydraulics Laboratory at Aalborg University from November 1995 through March 1996. The objective of the model tests was to investigate the hydraulic stability of Accropode armour layers...

  17. Hydraulic Stability of Accropode Armour

    Jensen, T.; Burcharth, H. F.; Frigaard, Peter

    , and to assess the influence of core permeability on the hydraulic stability of Accropodes. Two structures were examined, one with a relatively permeable core and one with a relatively impermeable core. In November/December 1995, Ph.D.-student Marten Christensen carried out the model tests on the structure...... with permeable core (crushed granite with a gradation of 5-8 mm). The outcome of this study is described in "Hydraulic Stability of Single-Layer Dolos and Accropode Armour Layers" by Christensen & Burcharth (1995). In January/February 1996, Research Assistant Thomas Jensen carried out a similar study......The present report describes the hydraulic model tests of Accropode armour layers carried out at the Hydraulics Laboratory at Aalborg University from November 1995 through March 1996. The objective of the model tests was to investigate the hydraulic stability of Accropode armour layers...

  18. Hydraulic Yaw System

    Stubkier, Søren; Pedersen, Henrik C.; Mørkholt, M.

    As wind turbines increase in size, combined with increased lifetime demands, new methods for load reduction needs to be examined. One method is to make the yaw system of the turbine soft/flexible and hereby dampen the loads to the system, which is the focus of the current paper. By utilizing...... the HAWC2 aeroelastic code and an extended model of the NREL 5MW turbine combined with a simplified linear model of the turbine, the parameters of the soft yaw system are optimized to reduce loading in critical components. Results shows that a significant reduction in fatigue and extreme loads to the yaw...... system and rotor shaft when utilizing the soft yaw drive concept compared to the original stiff yaw system. The physical demands of the hydraulic yaw system are furthermore examined for a life time of 20 years. Based on the extrapolated loads, the duty cycles show that it is possible to construct...

  19. Electro Hydraulic Hitch Control

    Hansen, M. R.; Andersen, T. O.; Nielsen, B.


    system for agricultural applications and driving for transportation. During tranport phases, the lack of suspension causes the vehicle to bounce and pitch, and makes it difficalt to control. Many systems have been proposed to cope with the oscillatory behavior, and different solutions exist. Common......This paper present and discusses R&D results on electro hydraulic hitch control for off-road vehicle, in particular active damping of oscillation occuring on tractors. The research deals with analysis and control of the oscillations occuring on tractors which are design without any susspection...... for most of the systems are that they operate on the hydrailc actuators generally providing the motive forces for moving the implement and/or attachment, typically a plough. The basic idea and physical working principle are to use the implement, moveable relative to the vehicle, as a damper mass. The paper...

  20. Concept Design of Movable Beam of Hydraulic Press

    Li Yancong


    Full Text Available The hydraulic press movable beam is one of the key components of the hydraulic press; its design quality impacts the accuracy of the workpiece that the press suppressed. In this paper, first, with maximum deflection and material strength as constraints, mechanical model of the movable beam is established; next, the concept design model of the moveable beam structure is established; the relationship among the force of the side cylinder, the thickness of the inclined plate, outer plate is established also. Taking movable beam of the 100MN type THP10-10000 isothermal forging hydraulic press as an example, the conceptual design result is given. This concept design method mentoned in the paper has general meaning and can apply to other similar product design.

  1. Tradeoffs between hydraulic and mechanical stress responses of mature Norway spruce trunk wood.

    Rosner, Sabine; Klein, Andrea; Müller, Ulrich; Karlsson, Bo


    We tested the effects of growth characteristics and basic density on hydraulic and mechanical properties of mature Norway spruce (Picea abies (L.) Karst.) wood from six 24-year-old clones, grown on two sites in southern Sweden differing in water availability. Hydraulic parameters assessed were specific hydraulic conductivity at full saturation (ks100) and vulnerability to cavitation (Psi50), mechanical parameters included bending strength (sigma b), modulus of elasticity (MOE), compression strength (sigma a) and Young's modulus (E). Basic density, diameter at breast height, tree height, and hydraulic and mechanical parameters varied considerably among clones. Clonal means of hydraulic and mechanical properties were strongly related to basic density and to growth parameters across sites, especially to diameter at breast height. Compared with stem wood of slower growing clones, stem wood of rapidly growing clones had significantly lower basic density, lower sigma b, MOE, sigma a and E, was more vulnerable to cavitation, but had higher ks100. Basic density was negatively correlated to Psi50 and ks100. We therefore found a tradeoff between Psi50 and ks100. Clones with high basic density had significantly lower hydraulic vulnerability, but also lower hydraulic conductivity at full saturation and thus less rapid growth than clones with low basic density. This tradeoff involved a negative relationship between Psi50 and sigma b as well as MOE, and between ks100 and sigma b, MOE and sigma a. Basic density and Psi50 showed no site-specific differences, but tree height, diameter at breast height, ks100 and mechanical strength and stiffness were significantly lower at the drier site. Basic density had no influence on the site-dependent differences in hydraulic and mechanical properties, but was strongly negatively related to diameter at breast height. Selecting for growth may thus lead not only to a reduction in mechanical strength and stiffness but also to a reduction in

  2. Hydraulic conductivity of compacted zeolites.

    Oren, A Hakan; Ozdamar, Tuğçe


    Hydraulic conductivities of compacted zeolites were investigated as a function of compaction water content and zeolite particle size. Initially, the compaction characteristics of zeolites were determined. The compaction test results showed that maximum dry unit weight (γ(dmax)) of fine zeolite was greater than that of granular zeolites. The γ(dmax) of compacted zeolites was between 1.01 and 1.17 Mg m(-3) and optimum water content (w(opt)) was between 38% and 53%. Regardless of zeolite particle size, compacted zeolites had low γ(dmax) and high w(opt) when compared with compacted natural soils. Then, hydraulic conductivity tests were run on compacted zeolites. The hydraulic conductivity values were within the range of 2.0 × 10(-3) cm s(-1) to 1.1 × 10(-7) cm s(-1). Hydraulic conductivity of all compacted zeolites decreased almost 50 times as the water content increased. It is noteworthy that hydraulic conductivity of compacted zeolite was strongly dependent on the zeolite particle size. The hydraulic conductivity decreased almost three orders of magnitude up to 39% fine content; then, it remained almost unchanged beyond 39%. Only one report was found in the literature on the hydraulic conductivity of compacted zeolite, which is in agreement with the findings of this study.

  3. Computed Tomography (CT) -- Head

    Full Text Available ... Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special ... the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT ...

  4. The composition and compression of biofilms developed on ultrafiltration membranes determine hydraulic biofilm resistance.

    Derlon, Nicolas; Grütter, Alexander; Brandenberger, Fabienne; Sutter, Anja; Kuhlicke, Ute; Neu, Thomas R; Morgenroth, Eberhard


    This study aimed at identifying how to improve the level of permeate flux stabilisation during gravity-driven membrane filtration without control of biofilm formation. The focus was therefore on understanding (i) how the different fractions of the biofilms (inorganics particles, bacterial cells, EPS matrix) influence its hydraulic resistance and (ii) how the compression of biofilms impacts its hydraulic resistance, i.e., can water head be increased to increase the level of permeate flux stabilisation. Biofilms were developed on ultrafiltration membranes at 88 and 284 cm water heads with dead-end filtration for around 50 days. A larger water head resulted in a smaller biofilm permeability (150 and 50 L m(-2) h(-1) bar(-1) for biofilms grown at 88 cm and 284 cm water head, respectively). Biofilms were mainly composed of EPS (>90% in volume). The comparison of the hydraulic resistances of biofilms to model fouling layers indicated that most of the hydraulic resistance is due to the EPS matrix. The compressibility of the biofilm was also evaluated by subjecting the biofilms to short-term (few minutes) and long-term variations of transmembrane pressures (TMP). A sudden change of TMP resulted in an instantaneous and reversible change of biofilm hydraulic resistance. A long-term change of TMP induced a slow change in the biofilm hydraulic resistance. Our results demonstrate that the response of biofilms to a TMP change has two components: an immediate variation of resistance (due to compression/relaxation) and a long-term response (linked to biofilm adaptation/growth). Our results provide relevant information about the relationship between the operating conditions in terms of TMP, the biofilm structure and composition and the resulting biofilm hydraulic resistance. These findings have practical implications for a broad range of membrane systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Strength Training

    ... strengthens your heart and lungs. When you strength train with weights, you're using your muscles to ... see there are lots of different ways to train with weights. Try a few good basic routines ...

  6. Strength Training

    ... en español Entrenamiento de la fuerza muscular Strength training is a vital part of a balanced exercise routine that includes aerobic activity and flexibility exercises. Regular aerobic exercise, such as running or ...

  7. FOREWORD: 26th IAHR Symposium on Hydraulic Machinery and Systems

    Wu, Yulin; Wang, Zhengwei; Liu, Shuhong; Yuan, Shouqi; Luo, Xingqi; Wang, Fujun


    The 26th IAHR Symposium on Hydraulic Machinery and Systems, will be held in Beijing, China, 19-23 August 2012. It is jointly organized by Tsinghua University, State Key Laboratory of Hydro Science and Hydraulic Engineering, China, Jiangsu University, Xi'an University of Technology, China Agricultural University, National Engineering Research Center of Hydropower Equipment and Dongfang Electric Machinery Co., Ltd. It is the second time that China hosts such a symposium. By the end of 2011, the China electrical power system had a total of 1 050 GW installed power, out of which 220 GW was in hydropower plants. The energy produced in hydropower facilities was 662.6 TWh from a total of 4,720 TWh electrical energy production in 2011. Moreover, in 2020, new hydropower capacities are going to be developed, with a total of 180 GW installed power and an estimated 708 TWh/year energy production. And in 2011, the installed power of pumped storage stations was about 25GW. In 2020, the data will be 70GW. At the same time, the number of pumps used in China is increasing rapidly. China produces about 29,000,000 pumps with more than 220 series per year. By the end of 2011, the Chinese pumping system has a total of 950 GW installed power. The energy consumed in pumping facilities was 530 TWh in 2011. The pump energy consumption accounted for about 12% of the national electrical energy production. Therefore, there is a large market in the field of hydraulic machinery including water turbines, pump turbines and a variety of pumps in China. There are also many research projects in this field. For example, we have conducted National Key Research Projects on 1000 MW hydraulic turbine, and on the pump turbines with high head, as well as on the large capacity pumps for water supply. Tsinghua University of Beijing is proud to host the 26th IAHR Symposium on Hydraulic Machinery and Systems. Tsinghua University was established in 1911, after the founding of the People's Republic of China. It

  8. Hydraulic conductivity of organomodified soil

    Wallace, R.B.; Grant, J.M.; Voice, T.C.; Rakhshandehroo, G.; Xu, S.; Boyd, S.A. [Michigan State Univ., East Lansing, MI (United States)


    The effects of organomodification on soil hydraulic conductivity were investigated. Hydraulic conductivity and porosity of treated and untreated samples of a sandy loam were measured as a function of effective stress. Batch treatment with hexadecyltrimethyl ammonium (HDTMA) and dry packing produced organomodified samples that were 79% less conducive than untreated samples prior to loading. Treated samples lost less hydraulic conductivity as a result of loading than untreated samples so that treated samples had higher conductivity at high loads. Observed differences in conductivity are explained in terms of the role of the treated and untreated clay in controlling initial effective pore size and its change during consolidation.

  9. Hydraulic Tomography at North Campus Research Site: Let Data Tell the Story

    Tso, C. H. M.; Yeh, T. C. J.


    Hydraulic tomography (HT) is a sequential cross-hole hydraulic test followed by inversion of the data to map the spatial distribution of aquifer hydraulic properties (Yeh and Liu, 2000). We provide a focused, qualitative discussion on the hydraulic tomography data reported in Berg and Illman (2011). At the North Campus Research Site (NCRS) of the University of Waterloo, 8 pumping tests are conducted sequentially at different locations of the well field while drawdown is monitored at 44 ports distributed at 8 other wells. Without conducting inverse modeling, we discuss the behavior of the drawdown curves and the temporal evolution head field in response to pumping location, heterogeneity in aquifer parameters (i.e. hydraulic conductivity (K) and specific storage (Ss)), flow regimes, and boundary conditions. We emphasize the importance and direct benefits for conducting hydraulic tomography surveys relies primarily on the collection of non-redundant data, not on the inverse models. This paper attempts to use an intuitive/logical approach to qualitative hydraulic tomography analysis. Our interpretation on the aquifer heterogeneity largely agrees with the intensive core sampling (i.e. local K measurements) and inverse modeling results. We conclude some of the inspection procedures can be beneficial before the inversion of data, while the quantitative and unifying estimation of hydraulic parameter fields can only be done using an inverse model.

  10. Measurement of soil hydraulic conductivity in relation with vegetation

    Chen, Xi; Cheng, Qinbo


    Hydraulic conductivity is a key parameter which influences hydrological processes of infiltration, surface and subsurface runoff. Vegetation alters surface characteristics (e.g., surface roughness, litter absorption) or subsurface characteristics (e.g. hydraulic conductivity). Field infiltration experiment of a single ring permeameter is widely used for measuring soil hydraulic conductivity. Measurement equipment is a simple single-ring falling head permeameter which consists of a hollow cylinder that is simply inserted into the top soil. An optimization method on the basis of objective of minimum error between the measured and simulated water depths in the single-ring is developed for determination of the soil hydraulic parameters. Using the single ring permeameter, we measured saturated hydraulic conductivities (Ks) of the red loam soil with and without vegetation covers on five hillslopes at Taoyuan Agro-Ecology Experimental Station, Hunan Province of China. For the measurement plots without vegetation roots, Ks value of the soil at 25cm depth is much smaller than that of surface soil (1.52×10-4 vs. 1.10×10-5 m/s). For the measurement plots with vegetation cover, plant roots significantly increase Ks of the lower layer soil but this increase is not significant for the shallow soil. Moreover, influences of vegetation root on Ks depend on vegetation species and ages. Ks value of the Camellia is about three times larger than that of seeding of Camphor (2.62×10-4 vs. 9.82×10-5 m/s). Ks value of the matured Camellia is 2.72×10-4 m/s while Ks value of the young Camellia is only 2.17×10-4 m/s. Key words: single ring permeameter; soil hydraulic conductivity; vegetation


    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...


    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...


    Federal Emergency Management Agency, Department of Homeland Security — This Hydraulic data was reviewed and approved by FEMA during the initial MT-2 processing. Recent developments in digital terrain and geospatial database management...


    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data in this submittal include spatial datasets and model outputs necessary for computation of the 1-percent flooding extent. The minimum requirement for...

  15. Hydraulic wind energy conversion system


    The purpose of this research was to design, build and test a hydraulic wind energy system. This design used a three bladed turbine, which drove a hydraulic pump. The energy is transmitted from the pump through a long hose and into a hydraulic motor, where the energy is used. This wind system was built and tested during the winter of 1980-1981. The power train included a five meter, three bladed wind turbine, a 9.8:1 ratio gearbox, a 1.44 cubic inch displacement pump with a small supercharge gear pump attached. The hydraulic fluid was pumped through a 70', 3/4'' I-D-high pressure flexhose, then through a volume control valve and into a 1.44 cubic inch displacement motor. The fluid was returned through a 70', 1'' I-D-flexhose.

  16. Head Position and Internally Headed Relative Clauses.

    Basilico, David


    Examines "Head Movement" in internally headed relative clauses (IHRCs). The article shows that in some cases, head movement to an external position need not take place and demonstrates that this movement of the head to a sentence-internal position results from the quantificational nature of IHRCs and Diesing's mapping hypothesis (1990, 1992). (56…

  17. 14 CFR 29.1435 - Hydraulic systems.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hydraulic systems. 29.1435 Section 29.1435... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows: (1) Each element of the hydraulic system...

  18. 14 CFR 23.1435 - Hydraulic systems.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hydraulic systems. 23.1435 Section 23.1435... § 23.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows: (1) Each hydraulic system and its elements must withstand, without yielding, the structural loads expected...

  19. 46 CFR 28.405 - Hydraulic equipment.


    ... 46 Shipping 1 2010-10-01 2010-10-01 false Hydraulic equipment. 28.405 Section 28.405 Shipping... Operate With More Than 16 Individuals on Board § 28.405 Hydraulic equipment. (a) Each hydraulic system... than four times the system maximum operating pressure. (c) Each hydraulic system must be equipped...

  20. Advanced Performance Hydraulic Wind Energy

    Jones, Jack A.; Bruce, Allan; Lam, Adrienne S.


    The Jet Propulsion Laboratory, California Institute of Technology, has developed a novel advanced hydraulic wind energy design, which has up to 23% performance improvement over conventional wind turbine and conventional hydraulic wind energy systems with 5 m/sec winds. It also has significant cost advantages with levelized costs equal to coal (after carbon tax rebate). The design is equally applicable to tidal energy systems and has passed preliminary laboratory proof-of-performance tests, as funded by the Department of Energy.

  1. Smart magnetic markers use in hydraulic fracturing.

    Zawadzki, Jarosław; Bogacki, Jan


    One of the main challenges and unknowns during shale gas exploration is to assess the range and efficiency of hydraulic fracturing. It is also essential to assess the distribution of proppant, which keeps the fracture pathways open. Solving these problems may considerably increase the efficiency of the shale gas extraction. Because of that, the idea of smart magnetic marker, which can be detected when added to fracturing fluid, has been considered for a long time. This study provides overview of the possibilities of magnetic marker application for shale gas extraction. The imaging methods using electromagnetic markers, are considered or developed in two directions. The first possibility is the markers' electromagnetic activity throughout the whole volume of the fracturing fluid. Thus, it can be assumed that the whole fracturing fluid is the marker. Among these type of hydraulic fracturing solutions, ferrofluid could be considered. The second possibility is marker, which is just one of many components of the fracturing fluid. In this case feedstock magnetic materials, ferrites and nanomaterials could be considered. Magnetic properties of magnetite could be too low and ferrofluids' or nanomaterials' price is unacceptably high. Because of that, ferrites, especially ZnMn ferrites seems to be the best material for magnetic marker. Because of the numerous applications in electronics, it is cheap and easily available, although the price is higher, then that of magnetite. The disadvantage of using ferrite, could be too small mechanical strength. It creates an essential need for combining magnetic marker with proppant into magnetic-ceramic composite.

  2. The application of explosive cladding technology in the process of hydraulic-cylinder production

    Soković, Mirko; Jovišević, Vid


    This paper treats the technologies for glide-pairs forming using bronze cladding and using the sheet-bronze explosive cladding technique over the glide surfaces of a steel hydraulic cylinder. In the paper the microhardness, the microstructure and the bond strength of the interface of a bi-metallic joint on the cross-section of the test hydraulic cylinder were investigated. A parallel results survey of the application of these two technologies is shown based on metallographic and mechanical in...

  3. Research on hydraulic slotting technology controlling coal-gas outbursts

    WEI Guo-ying; SHAN Zhi-yong; ZHANG Zi-min


    Measured to control serious coal-gas outburst in coal seam were analyzed by theory and experimented in test site. A new technique to distress the coal-bed and drain methane, called hydraulic slotting, was described in detail, and the mechanism of hydrau-lic slotting was put forward and analyzed. The characteristic parameter of hydraulic slotting was given in Jiaozuo mining area and the characteristic of validity, adaptability and secu-rity was evaluated. The results show that the stress surrounding the strata and the gas in coal seam is released efficiently and thoroughly while new techniques are taken, as slot-ting at heading face by high pressure large diameter jet. The resistance to coal and gas outbursts is increased dramatically once the area of slotting is increased to a certain size.In the process of driving 2 000 m tunnel by hydraulic slotting excavation, coal and gas outburst never occurre. The technique could be used to prevent and control potential coal-gas outburst in the proceeding of tunnel driving, and the speed tunneling could be as high as more than 2 times.

  4. Valorization of phosphogypsum as hydraulic binder.

    Kuryatnyk, T; Angulski da Luz, C; Ambroise, J; Pera, J


    Phosphogypsum (calcium sulfate) is a naturally occurring part of the process of creating phosphoric acid (H(3)PO(4)), an essential component of many modern fertilizers. For every tonne of phosphoric acid made, from the reaction of phosphate rock with acid, commonly sulfuric acid, about 3t of phosphogypsum are created. There are three options for managing phosphogypsum: (i) disposal or dumping, (ii) stacking, (iii) use-in, for example, agriculture, construction, or landfill. This paper presents the valorization of two Tunisian phosphogypsums (referred as G and S) in calcium sulfoaluminate cement in the following proportions: 70% phosphogypsum-30% calcium sulfoaluminate clinker. The use of sample G leads to the production of a hydraulic binder which means that it is not destroyed when immersed in water. The binder including sample S performs very well when cured in air but is not resistant in water. Formation of massive ettringite in a rigid body leads to cracking and strength loss.

  5. Avaliação hidráulica de um sistema de irrigação localizada de baixa pressão, projetado pelo software "bubbler" Design and hydraulics evaluation of a low-head microirrigation, bubbler system

    Ivam H. de Souza


    Full Text Available Conduziu-se este trabalho com o objetivo de avaliar o desempenho de um sistema de irrigação a baixa pressão, bubbler, em condições de campo. A avaliação consistiu de um estudo dividido em duas fases, em que, na primeira, foi elaborado o dimensionamento hidráulico do sistema de irrigação, com uso do programa computacional Bubbler versão 1.1, enquanto, na segunda fase, ocorreram a instalação e os testes de campo. Estabeleceram-se as alturas de 0,77; 0,71; 0,68 e 0,67 m na saída das mangueiras emissoras no campo, conforme recomendação do programa. Foram feitas as avaliações de vazão em cada mangueira emissora, para determinar o Coeficiente de Uniformidade de Christiansen (CUC, a Uniformidade de Distribuição (UD e a Eficiência de Aplicação (EA. Os testes mostraram CUC igual a 96,64%, UD igual a 95,85% e EA igual a 86,98%. O sistema no campo proporcionou vazão média de 64,8 L h-1 contra os 79,2 L h-1 estabelecidos pelo programa. Os valores encontrados de vazão diferiram dos valores projetados pelo aplicativo, em conseqüência da variação dos diâmetros e das perdas de carga (linear e localizada que apresentaram desvio-padrão de 0,23 m.This work was done with the objective of evaluating a low-pressure irrigation system (bubbler system, under field conditions. This evaluation consisted of a study divided in two phases: in the first, the hydraulic design of the irrigation system was elaborated with the use of the software named Bubbler version 1.1; while, in the second phase the installation and the field tests were done. Volumetric tests were accomplished in each emission hose to determine: the flow variation, the coefficients of uniformity, and the application efficiency. It was established the heights of the emitter hose exit at 0.77; 0.71; 0.68 and 0.67 m, on the field, following the recommendation of the software. The tests showed a Christiansen's Uniformity Coefficient (CUC of 96.64%, a Distribution Uniformity (DU of

  6. Scale dependence of the hydraulic properties of a fractured aquifer estimated using transfer functions

    Pedretti, D.; Russian, A.; Sanchez-Vila, X.; Dentz, M.


    We present an investigation of the scale dependence of hydraulic parameters in fractured media based on the concept of transfer functions (TF). TF methods provide an inexpensive way to perform aquifer parameter estimation, as they relate the fluctuations of an observation time series (hydraulic head fluctuations) to an input function (aquifer recharge) in frequency domain. Fractured media are specially sensitive to this approach as hydraulic parameters are strongly scale-dependent, involving nonstationary statistical distributions. Our study is based on an extensive data set, involving up to 130 measurement points with periodic head measurements that in some cases extend for more than 30 years. For each point, we use a single-porosity and dual-continuum TF formulation to obtain a distribution of transmissivities and storativities in both mobile and immobile domains. Single-porosity TF estimates are compared with data obtained from the interpretation of over 60 hydraulic tests (slug and pumping tests). Results show that the TF is able to estimate the scale dependence of the hydraulic parameters, and it is consistent with the behavior of estimates from traditional hydraulic tests. In addition, the TF approach seems to provide an estimation of the system variance and the extension of the ergodic behavior of the aquifer (estimated in approximately 500 m in the analyzed aquifer). The scale dependence of transmissivity seems to be independent from the adopted formulation (single or dual-continuum), while storativity is more sensitive to the presence of multiple continua.

  7. Technologies and Innovations for Hydraulic Pumps

    Ivantysynova, Monika


    Positive displacement machines working as hydraulic pumps or hydraulic motors have always been, are and will be an essential part of any hydraulic system. Current trends and future demands on energy efficient systems will not only drastically increase the number of positive displacement machines needed for modern efficient hydraulic circuits but will significantly change the performance requirements of pumps and motors. Throttleless system configurations will change the landscape of hydraulic...

  8. The Comparison of Predicted and Measured Hydraulic Conductivities of Soils having Different Physical Properties

    Zengin, Enes; Abiddin Erguler, Zeynal; Karakuş, Hüseyin


    Hydraulic conductivity is one of the most important parameter of earth science related studies such as engineering geology, soil physics, agriculture etc. In order to estimate the ability of soils to transport fluid through particles, field and laboratory tests have been performed since last decades of 19th century. Constant and falling head tests are widely used to directly measure hydraulic conductivity values in laboratory conditions for soils having different particle size distributions. The determination of hydraulic conductivity of soils by performing these methods are time consuming processes and also requires undisturbed samples to reflect in-situ natural condition. Considering these limitations, numerous approaches have been proposed to practically estimate hydraulic conductivity of soils by utilizing empirical equations based on simple physical and index properties such as grain size distribution curves related parameters, porosity, void ratio, etc. Many previous studies show that the hydraulic conductivity values calculated by empirical equations deviate more than two order magnitude than the measured hydraulic conductivity values obtained from convenient permeability tests. In order to investigate the main controlling parameters on hydraulic conductivity of soils, a comprehensive research program was carried out on some disturbed and undisturbed soil samples collected from different locations in Turkey. The hydraulic conductivity values of samples were determined as changing between 10-6 and 10-9 m/s by using falling head tests. In addition to these tests, basic soil properties such as natural water content, Atterberg limits, specific gravity and grain size analyses of these samples were also defined to be used as an input parameters of empirical equations for prediction hydraulic conductivity values. In addition, data from previous studies were also used for the aim of this study. The measured hydraulic conductivity values were correlated with all

  9. Cervical Resistance Training: Effects on Isometric and Dynamic Strength


    skinfold thicknesses . San Diego, CA: Naval Health Research Center; 1984. Report No: 84–39. 3. Coakwell MR, Bloswick DS, Moser R Jr. High-risk head and...Strength, Dynamic Strength, and Neck Circumference Isometric strength values are displayed in Table I. For isometric strength-flexion, the 2 2 ANOVA...Also, a main effect was observed TABLE I. RESISTANCE TRAINING VS. CONTROL GROUPS: ISOMETRIC STRENGTH (LB). RT Group (n 5) C Group (n 5) FLX EXT

  10. On the Choice of Structure and Layout of Rubble Mound Breakwater Heads

    Maciñeira, Enrique; Burcharth, Hans F.


     The paper discusses the various functional, environmental and structural conditions to consider related to the choice of breakwater head type. Results from hydraulic model tests of rubble mound and caisson head solutions for the new deep water port at Punto Langosteira, La Coruña, Spain, are pre...

  11. Estimating Hydraulic Parameters When Poroelastic Effects Are Significant

    Berg, S.J.; Hsieh, P.A.; Illman, W.A.


    For almost 80 years, deformation-induced head changes caused by poroelastic effects have been observed during pumping tests in multilayered aquifer-aquitard systems. As water in the aquifer is released from compressive storage during pumping, the aquifer is deformed both in the horizontal and vertical directions. This deformation in the pumped aquifer causes deformation in the adjacent layers, resulting in changes in pore pressure that may produce drawdown curves that differ significantly from those predicted by traditional groundwater theory. Although these deformation-induced head changes have been analyzed in several studies by poroelasticity theory, there are at present no practical guidelines for the interpretation of pumping test data influenced by these effects. To investigate the impact that poroelastic effects during pumping tests have on the estimation of hydraulic parameters, we generate synthetic data for three different aquifer-aquitard settings using a poroelasticity model, and then analyze the synthetic data using type curves and parameter estimation techniques, both of which are based on traditional groundwater theory and do not account for poroelastic effects. Results show that even when poroelastic effects result in significant deformation-induced head changes, it is possible to obtain reasonable estimates of hydraulic parameters using methods based on traditional groundwater theory, as long as pumping is sufficiently long so that deformation-induced effects have largely dissipated. ?? 2011 The Author(s). Journal compilation ?? 2011 National Ground Water Association.

  12. Multiple Small Diameter Drillings Increase Femoral Neck Stability Compared with Single Large Diameter Femoral Head Core Decompression Technique for Avascular Necrosis of the Femoral Head.

    Brown, Philip J; Mannava, Sandeep; Seyler, Thorsten M; Plate, Johannes F; Van Sikes, Charles; Stitzel, Joel D; Lang, Jason E


    Femoral head core decompression is an efficacious joint-preserving procedure for treatment of early stage avascular necrosis. However, postoperative fractures have been described which may be related to the decompression technique used. Femoral head decompressions were performed on 12 matched human cadaveric femora comparing large 8mm single bore versus multiple 3mm small drilling techniques. Ultimate failure strength of the femora was tested using a servo-hydraulic material testing system. Ultimate load to failure was compared between the different decompression techniques using two paired ANCOVA linear regression models. Prior to biomechanical testing and after the intervention, volumetric bone mineral density was determined using quantitative computed tomography to account for variation between cadaveric samples and to assess the amount of bone disruption by the core decompression. Core decompression, using the small diameter bore and multiple drilling technique, withstood significantly greater load prior to failure compared with the single large bore technique after adjustment for bone mineral density (pcore decompression techniques. When considering core decompression for the treatment of early stage avascular necrosis, the multiple small bore technique removed less bone volume, thereby potentially leading to higher load to failure.

  13. Analytical solution to problems of hydraulic jump in horizontal triangular channels

    I.M.H. Rashwan


    Full Text Available A hydraulic jump is formed in a channel whenever supercritical flow changes to subcritical flow in a short distance. It can be used in triangular ditch irrigation to raise the downstream water surface. The basic elements and characteristics of the hydraulic jump are provided to aid designers in selecting more practical basins. In the present study, the slope side, discharge and the energy loss in hydraulic jump in horizontal triangular section are known whereas one has to obtain the sequent depths. The specific force and specific energy equations in a horizontal triangular open channel are made dimensionless, writing it for the sequent depths as a function of discharge and head loss. The proposed modes for hydraulic jump elements are of high accuracy and applicable to a wide range of discharge intensity values and initial conditions without any limitations for the assumptions under consideration.

  14. Hamiltonian Monte Carlo algorithm for the characterization of hydraulic conductivity from the heat tracing data

    Djibrilla Saley, A.; Jardani, A.; Soueid Ahmed, A.; Raphael, A.; Dupont, J. P.


    Estimating spatial distributions of the hydraulic conductivity in heterogeneous aquifers has always been an important and challenging task in hydrology. Generally, the hydraulic conductivity field is determined from hydraulic head or pressure measurements. In the present study, we propose to use temperature data as source of information for characterizing the spatial distributions of the hydraulic conductivity field. In this way, we performed a laboratory sandbox experiment with the aim of imaging the heterogeneities of the hydraulic conductivity field from thermal monitoring. During the laboratory experiment, we injected a hot water pulse, which induces a heat plume motion into the sandbox. The induced plume was followed by a set of thermocouples placed in the sandbox. After the temperature data acquisition, we performed a hydraulic tomography using the stochastic Hybrid Monte Carlo approach, also called the Hamiltonian Monte Carlo (HMC) algorithm to invert the temperature data. This algorithm is based on a combination of the Metropolis Monte Carlo method and the Hamiltonian dynamics approach. The parameterization of the inverse problem was done with the Karhunen-Loève (KL) expansion to reduce the dimensionality of the unknown parameters. Our approach has provided successful reconstruction of the hydraulic conductivity field with low computational effort.

  15. Near-saturated hydraulic conductivity: database development, meta-analysis and pedotransfer functions

    Jarvis, Nicholas; Koestel, John; Messing, Ingmar; Lindahl, Anna


    Near-saturated hydraulic conductivity exerts a critical control on water flow and solute transport through the vadose zone, yet very little is known concerning how it is influenced by various soil properties and site factors and attributes. Starting from the 1980's, tension infiltrometers or disc permeameters have become an increasingly popular method to measure near-saturated hydraulic conductivity in undisturbed soil. In this presentation, we describe the development and organization of a large database of tension infiltrometer measurements (n>700) collated from the published literature. The raw datasets were standardized and summarized using a modified Kozeny-Carman model of near-saturated hydraulic conductivity (Jarvis, N.J. 2008. Near-saturated hydraulic properties of macroporous soils. Vadose Zone Journal, 7, 1302-1310). This model was found to accurately describe near-saturated conductivity for this large dataset (92% of cases had R2 values larger than 0.9). We will show the results of some initial analyses of the dataset, which show how hydraulic conductivity at pressure heads of -1 and -10 cm, as well as the slope of the near-saturated conductivity function, are affected by: i.) the choice of method to convert unconfined 3D infiltration to hydraulic conductivity, and ii.) interactions between soil properties such as texture and bulk density and site attributes such as land use and climate. We will also present some initial attempts to develop pedotransfer functions for parameters describing near-saturated hydraulic conductivity using the technique of random forests.

  16. Combining 3D Hydraulic Tomography with Tracer Tests for Improved Transport Characterization.

    Sanchez-León, E; Leven, C; Haslauer, C P; Cirpka, O A


    Hydraulic tomography (HT) is a method for resolving the spatial distribution of hydraulic parameters to some extent, but many details important for solute transport usually remain unresolved. We present a methodology to improve solute transport predictions by combining data from HT with the breakthrough curve (BTC) of a single forced-gradient tracer test. We estimated the three dimensional (3D) hydraulic-conductivity field in an alluvial aquifer by inverting tomographic pumping tests performed at the Hydrogeological Research Site Lauswiesen close to Tübingen, Germany, using a regularized pilot-point method. We compared the estimated parameter field to available profiles of hydraulic-conductivity variations from direct-push injection logging (DPIL), and validated the hydraulic-conductivity field with hydraulic-head measurements of tests not used in the inversion. After validation, spatially uniform parameters for dual-domain transport were estimated by fitting tracer data collected during a forced-gradient tracer test. The dual-domain assumption was used to parameterize effects of the unresolved heterogeneity of the aquifer and deemed necessary to fit the shape of the BTC using reasonable parameter values. The estimated hydraulic-conductivity field and transport parameters were subsequently used to successfully predict a second independent tracer test. Our work provides an efficient and practical approach to predict solute transport in heterogeneous aquifers without performing elaborate field tracer tests with a tomographic layout.

  17. Is HEADS in our heads?

    Boisen, Kirsten A; Hertz, Pernille Grarup; Blix, Charlotte


    BACKGROUND: Outpatient clinic visits are a window of opportunity to address health risk behaviors and promote a healthier lifestyle among young people. The HEADS (Home, Education, Eating, Activities, Drugs [i.e. substance use including tobacco, alcohol, and illegal drugs], Sexuality [including...... care professionals participated. We found only small reported differences between staff and young patients regarding whether home, education, and activity were addressed. However, staff reported twice the rate of addressing smoking, alcohol, illegal drugs, sexuality, and contraception compared to young...... patients. Young patients reported that smoking, alcohol, illegal drugs, sexuality, and contraception were addressed significantly more at adult clinics in comparison to pediatric clinics. After controlling for age, gender and duration of illness, according to young patients, adjusted odds ratios...


    Dixon, K; John Harbour, J; Mark Phifer, M


    The Saltstone Disposal Facility (SDF), located in the Z-Area of the Savannah River Site (SRS), is used for the disposal of low-level radioactive salt solution. The SDF currently contains two vaults: Vault 1 (6 cells) and Vault 4 (12 cells). Additional disposal cells are currently in the design phase. The individual cells of the saltstone facility are filled with saltstone. Saltstone is produced by mixing the low-level radioactive salt solution, with blast furnace slag, fly ash, and cement (dry premix) to form a dense, micro-porous, monolithic, low-level radioactive waste form. The saltstone is pumped into the disposal cells where it subsequently solidifies. Significant effort has been undertaken to accurately model the movement of water and contaminants through the facility. Key to this effort is an accurate understanding of the hydraulic and physical properties of the solidified saltstone. To date, limited testing has been conducted to characterize the saltstone. The primary focus of this task was to estimate the hydraulic and physical properties of three types of saltstone and two vault concretes. The saltstone formulations included saltstone premix batched with (1) Deliquification, Dissolution, and Adjustment (DDA) salt simulant (w/pm 0.60), (2) Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) salt simulant (w/pm 0.60), and (3) Salt Waste Processing Facility (SWPF) salt simulant (w/pm 0.60). The vault concrete formulations tested included the Vault 1/4 concrete and two variations of the Vault 2 concrete (Mix 1 and Mix 2). Wet properties measured for the saltstone formulations included yield stress, plastic viscosity, wet unit weight, bleed water volume, gel time, set time, and heat of hydration. Hydraulic and physical properties measured on the cured saltstone and concrete samples included saturated hydraulic conductivity, moisture retention, compressive strength, porosity, particle density, and dry bulk density. These properties

  19. Complex Fluids and Hydraulic Fracturing.

    Barbati, Alexander C; Desroches, Jean; Robisson, Agathe; McKinley, Gareth H


    Nearly 70 years old, hydraulic fracturing is a core technique for stimulating hydrocarbon production in a majority of oil and gas reservoirs. Complex fluids are implemented in nearly every step of the fracturing process, most significantly to generate and sustain fractures and transport and distribute proppant particles during and following fluid injection. An extremely wide range of complex fluids are used: naturally occurring polysaccharide and synthetic polymer solutions, aqueous physical and chemical gels, organic gels, micellar surfactant solutions, emulsions, and foams. These fluids are loaded over a wide range of concentrations with particles of varying sizes and aspect ratios and are subjected to extreme mechanical and environmental conditions. We describe the settings of hydraulic fracturing (framed by geology), fracturing mechanics and physics, and the critical role that non-Newtonian fluid dynamics and complex fluids play in the hydraulic fracturing process.

  20. Hydraulic properties of ladle slags

    J. Vlček


    Full Text Available The article presents results of examining of hydraulic properties of ladle slags formed during production of steel. The studied ladle slags were subjected to different cooling mode from the molten state. Based on the ability of the slag react with the water was assessed their hydraulic activity. The hydraulic properties are caused by the presence of minerals dicalcium silicate, tricalcium aluminate, mayenite, brownmillerite and dicalcium ferite. The emergence of required hydrating phases in the ladle slags is conditioned by a sufficient CaO content and their cooling rate. The contact the slag with water during processing and their ageing has a negative effect. The experiment has shown that the phase transformation of the mineral dicalcium silicate which occurs during cooling of the ladle slags cause their volume instability.

  1. Computed Tomography (CT) -- Head

    Full Text Available ... of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT scanning of the head is typically ...

  2. Computed Tomography (CT) -- Head

    Full Text Available ... of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT scanning of the head is typically ...

  3. Hydraulic resistance of biofilms

    Dreszer, C.


    Biofilms may interfere with membrane performance in at least three ways: (i) increase of the transmembrane pressure drop, (ii) increase of feed channel (feed-concentrate) pressure drop, and (iii) increase of transmembrane passage. Given the relevance of biofouling, it is surprising how few data exist about the hydraulic resistance of biofilms that may affect the transmembrane pressure drop and membrane passage. In this study, biofilms were generated in a lab scale cross flow microfiltration system at two fluxes (20 and 100Lm-2h-1) and constant cross flow (0.1ms-1). As a nutrient source, acetate was added (1.0mgL-1 acetate C) besides a control without nutrient supply. A microfiltration (MF) membrane was chosen because the MF membrane resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric substances (EPS) were determined, it was demonstrated that no internal membrane fouling occurred and that the fouling layer actually consisted of a grown biofilm and was not a filter cake of accumulated bacterial cells. At 20Lm-2h-1 flux with a nutrient dosage of 1mgL-1 acetate C, the resistance after 4 days reached a value of 6×1012m-1. At 100Lm-2h-1 flux under the same conditions, the resistance was 5×1013m-1. No correlation of biofilm resistance to biofilm thickness was found; Biofilms with similar thickness could have different resistance depending on the applied flux. The cell number in biofilms was between 4×107 and 5×108 cellscm-2. At this number, bacterial cells make up less than a half percent of the overall biofilm volume and therefore did not hamper the water flow through the biofilm significantly. A flux of 100Lm-2h-1 with nutrient supply caused higher cell numbers, more biomass, and higher biofilm resistance than a flux of 20Lm-2h-1. However, the biofilm thickness

  4. Controls of Hydraulic Wind Turbine

    Zhang Yin


    Full Text Available In this paper a hydraulic wind turbine generator system was proposed based on analysis the current wind turbines technologies. The construction and principles were introduced. The mathematical model was verified using MATLAB and AMsim. A displacement closed loop of swash plate of motor and a speed closed loop of generator were setup, a PID control is introduced to maintain a constant speed and fixed frequency at wind turbine generator. Simulation and experiment demonstrated that the system can connect grid to generate electric and enhance reliability. The control system demonstrates a high performance speed regulation and effectiveness. The results are great significant to design a new type hydraulic wind turbine system.

  5. 新型石油钻杆液压矫直机结构分析%Analysis and Design of Oil Drill Pipe Hydraulic Straightening Machine

    石永军; 白立剑; 王维旭


    Considering the disadvantages of the existing drill pipe hydraulic straightening machines which have low straightening accuracy and low efficiency,a new kind of drill pipe hydraulic straightening machine was designed,adopting three-point straightening principle to straighten curving drill pipe.Its rotating mechanism first rotates the curving drill pipe and detects the curving position,and then the movable machine moves the drill pipe to make the curving position aligned to the pressure head.The finite element method is used to check the key parts of strength,which satisfied the operating requirement.%目前的钻杆矫直装置存在矫直精度低和工作效率低的问题.设计了一种新型的石油钻杆液压矫直机.采用三点矫直原理对弯曲钻杆进行矫直,通过旋转机构旋转钻杆,并检测出弯曲位置.由移动式主机移动钻杆,使弯曲位置对准压头,提高了工作效率和矫直精度.应用有限元方法分析了关键部件的强度,满足使用要求.

  6. Integrating hydraulic equivalent sections into a hydraulic geometry study

    Jia, Yanhong; Yi, Yujun; Li, Zhiwei; Wang, Zhaoyin; Zheng, Xiangmin


    Hydraulic geometry (HG) is an important geomorphic concept that has played an indispensable role in hydrological analyses, physical studies of streams, ecosystem and aquatic habitat studies, and sedimentology research. More than 60 years after Leopold and Maddock (1953) first introduced the concept of HG, researchers have still not uncovered the physical principles underlying HG behavior. One impediment is the complexity of the natural river cross section. The current study presents a new way to simplify the cross section, namely, the hydraulic equivalent section, which is generalized from the cross section in the ;gradually varied flow of an alluvial river; (GVFAR) and features hydrodynamic properties and bed-building laws similar to those of the GVFAR. Energy balance was used to derive the stage Z-discharge Q relationship in the GVFAR. The GVFAR in the Songhua River and the Yangtze River were selected as examples. The data, including measured discharge, river width, water stage, water depth, wet area, and cross section, were collected from the hydrological yearbooks of typical hydrological stations on the Songhua River and the Yangtze River from 1955 to 1987. The relationships between stage Z-discharge Q and cross-sectional area A-stage Z at various stations were analyzed, and ;at-a-station hydraulic geometry; (AHG) relationships were obtained in power-law forms. Based on derived results and observational data analysis, the Z-Q and Z-A relationships of AHG were similar to rectangular weir flows, thus the cross section of the GVFAR was generalized as a compound rectangular, hydraulic equivalent cross section. As to bed-building characteristics, the bankfull discharge method and the stage-discharge-relation method were used to calculate the dominant variables of the alluvial river. This hydraulic equivalent section has the same Z-Q relation, Z-A relation, dominant discharge, dominant river width, and dominant water depth as the cross section in the GVFAR. With the

  7. Head Impact Laboratory (HIL)

    Federal Laboratory Consortium — The HIL uses testing devices to evaluate vehicle interior energy attenuating (EA) technologies for mitigating head injuries resulting from head impacts during mine/...

  8. A performance-based method for calculating the design thickness of compacted clay liners exposed to high strength leachate under simulated landfill conditions.

    Safari, Edwin; Jalili Ghazizade, Mahdi; Abdoli, Mohammad Ali


    Compacted clay liners (CCLs) when feasible, are preferred to composite geosynthetic liners. The thickness of CCLs is typically prescribed by each country's environmental protection regulations. However, considering the fact that construction of CCLs represents a significant portion of overall landfill construction costs; a performance based design of liner thickness would be preferable to 'one size fits all' prescriptive standards. In this study researchers analyzed the hydraulic behaviour of a compacted clayey soil in three laboratory pilot scale columns exposed to high strength leachate under simulated landfill conditions. The temperature of the simulated CCL at the surface was maintained at 40 ± 2 °C and a vertical pressure of 250 kPa was applied to the soil through a gravel layer on top of the 50 cm thick CCL where high strength fresh leachate was circulated at heads of 15 and 30 cm simulating the flow over the CCL. Inverse modelling using HYDRUS-1D indicated that the hydraulic conductivity after 180 days was decreased about three orders of magnitude in comparison with the values measured prior to the experiment. A number of scenarios of different leachate heads and persistence time were considered and saturation depth of the CCL was predicted through modelling. Under a typical leachate head of 30 cm, the saturation depth was predicted to be less than 60 cm for a persistence time of 3 years. This approach can be generalized to estimate an effective thickness of a CCL instead of using prescribed values, which may be conservatively overdesigned and thus unduly costly.

  9. Modeling transient streaming potentials in falling-head permeameter tests.

    Malama, Bwalya; Revil, André


    We present transient streaming potential data collected during falling-head permeameter tests performed on samples of two sands with different physical and chemical properties. The objective of the work is to estimate hydraulic conductivity (K) and the electrokinetic coupling coefficient (Cl ) of the sand samples. A semi-empirical model based on the falling-head permeameter flow model and electrokinetic coupling is used to analyze the streaming potential data and to estimate K and Cl . The values of K estimated from head data are used to validate the streaming potential method. Estimates of K from streaming potential data closely match those obtained from the associated head data, with less than 10% deviation. The electrokinetic coupling coefficient was estimated from streaming potential vs. (1) time and (2) head data for both sands. The results indicate that, within limits of experimental error, the values of Cl estimated by the two methods are essentially the same. The results of this work demonstrate that a temporal record of the streaming potential response in falling-head permeameter tests can be used to estimate both K and Cl . They further indicate the potential for using transient streaming potential data as a proxy for hydraulic head in hydrogeology applications.

  10. Heading and head injuries in soccer.

    Kirkendall, D T; Jordan, S E; Garrett, W E


    In the world of sports, soccer is unique because of the purposeful use of the unprotected head for controlling and advancing the ball. This skill obviously places the player at risk of head injury and the game does carry some risk. Head injury can be a result of contact of the head with another head (or other body parts), ground, goal post, other unknown objects or even the ball. Such impacts can lead to contusions, fractures, eye injuries, concussions or even, in rare cases, death. Coaches, players, parents and physicians are rightly concerned about the risk of head injury in soccer. Current research shows that selected soccer players have some degree of cognitive dysfunction. It is important to determine the reasons behind such deficits. Purposeful heading has been blamed, but a closer look at the studies that focus on heading has revealed methodological concerns that question the validity of blaming purposeful heading of the ball. The player's history and age (did they play when the ball was leather and could absorb significant amounts of water), alcohol intake, drug intake, learning disabilities, concussion definition and control group use/composition are all factors that cloud the ability to blame purposeful heading. What does seem clear is that a player's history of concussive episodes is a more likely explanation for cognitive deficits. While it is likely that the subconcussive impact of purposeful heading is a doubtful factor in the noted deficits, it is unknown whether multiple subconcussive impacts might have some lingering effects. In addition, it is unknown whether the noted deficits have any affect on daily life. Proper instruction in the technique is critical because if the ball contacts an unprepared head (as in accidental head-ball contacts), the potential for serious injury is possible. To further our understanding of the relationship of heading, head injury and cognitive deficits, we need to: learn more about the actual impact of a ball on the




    This Calculation Note performs and documents MCNP criticality calculations for plutonium (100% {sup 239}Pu) hydraulic fluid mixtures. Spherical geometry was used for these generalized criticality safety calculations and three geometries of neutron reflection are: {sm_bullet}bare, {sm_bullet}1 inch of hydraulic fluid, or {sm_bullet}12 inches of hydraulic fluid. This document shows the critical volume and critical mass for various concentrations of plutonium in hydraulic fluid. Between 1 and 2 gallons of hydraulic fluid were discovered in the bottom of HA-23S. This HA-23S hydraulic fluid was reported by engineering to be Fyrquel 220. The hydraulic fluid in GLovebox HA-23S is Fyrquel 220 which contains phosphorus. Critical spherical geometry in air is calculated with 0 in., 1 in., or 12 inches hydraulic fluid reflection.

  12. DCS Hydraulics Submittal, Butler County, Alabama, USA

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  13. DCS Hydraulics Submittal, Bullock County, Alabama, USA

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  14. DCS Hydraulics Submittal, Covington County, Alabama, USA

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  15. High Pressure Hydraulic Distribution System


    to 500 0 F. 5 cycles. 5000 F room temperature to 50001F; 45 ______________ Icycles The tesis planned for the distribution system demonstrator were...American Society for Testing and Materials ASTM D412 - Tension Testing of Vulcanized Rubber ASTM D571 - Testing Automotive Hydraulic Brake Hose Society of

  16. Hydraulic fracturing system and method

    Ciezobka, Jordan; Salehi, Iraj


    A hydraulic fracturing system and method for enhancing effective permeability of earth formations to increase hydrocarbon production, enhance operation efficiency by reducing fluid entry friction due to tortuosity and perforation, and to open perforations that are either unopened or not effective using traditional techniques, by varying a pump rate and/or a flow rate to a wellbore.

  17. Hydraulic jumps in a channel

    Bonn, D.; Andersen, Anders Peter; Bohr, Tomas


    We present a study of hydraulic jumps with flow predominantly in one direction, created either by confining the flow to a narrow channel with parallel walls or by providing an inflow in the form of a narrow sheet. In the channel flow, we find a linear height profile upstream of the jump as expected...

  18. Hydraulic Fracture Containment in Sand

    Dong, Y.


    The mechanism of hydraulic fracturing in soft, high permeability material is considered fundamentally different from that in hard, low permeability rock, where a tensile fracture is created and conventional linear elastic fracture mechanics (LEFM) applies. The fracturing and associated modeling work

  19. Design of hydraulic recuperation unit

    Jandourek Pavel


    Full Text Available This article deals with design and measurement of hydraulic recuperation unit. Recuperation unit consist of radial turbine and axial pump, which are coupled on the same shaft. Speed of shaft with impellers are 6000 1/min. For economic reasons, is design of recuperation unit performed using commercially manufactured propellers.

  20. Tree Hydraulics: How Sap Rises

    Denny, Mark


    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  1. Tree Hydraulics: How Sap Rises

    Denny, Mark


    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  2. A new linear type hydraulic motor

    Jiang, Dong; Zhang, Tong; Li, Wenhua; Chen, Xinyang


    This paper proposes the design of liner type hydraulic motor on the base of inner curved radial piston hydraulic motor. The hydraulic cylinders of the new type motor are in the straight line which will improve the utilization of the axial space and different out power can be supplied by changes the number of cylinders. In this paper, the structure and working principle of the liner type hydraulic motor is introduced.

  3. Attitude Strength.

    Howe, Lauren C; Krosnick, Jon A


    Attitude strength has been the focus of a huge volume of research in psychology and related sciences for decades. The insights offered by this literature have tremendous value for understanding attitude functioning and structure and for the effective application of the attitude concept in applied settings. This is the first Annual Review of Psychology article on the topic, and it offers a review of theory and evidence regarding one of the most researched strength-related attitude features: attitude importance. Personal importance is attached to an attitude when the attitude is perceived to be relevant to self-interest, social identification with reference groups or reference individuals, and values. Attaching personal importance to an attitude causes crystallizing of attitudes (via enhanced resistance to change), effortful gathering and processing of relevant information, accumulation of a large store of well-organized relevant information in long-term memory, enhanced attitude extremity and accessibility, enhanced attitude impact on the regulation of interpersonal attraction, energizing of emotional reactions, and enhanced impact of attitudes on behavioral intentions and action. Thus, important attitudes are real and consequential psychological forces, and their study offers opportunities for addressing behavioral change.

  4. Minimizing Head Acceleration in Soccer: A Review of the Literature.

    Caccese, Jaclyn B; Kaminski, Thomas W


    Physicians and healthcare professionals are often asked for recommendations on how to keep athletes safe during contact sports such as soccer. With an increase in concussion awareness and concern about repetitive subconcussion, many parents and athletes are interested in mitigating head acceleration in soccer, so we conducted a literature review on factors that affect head acceleration in soccer. We searched electronic databases and reference lists to find studies using the keywords 'soccer' OR 'football' AND 'head acceleration'. Because of a lack of current research in soccer heading biomechanics, this review was limited to 18 original research studies. Low head-neck segment mass predisposes athletes to high head acceleration, but head-neck-torso alignment during heading and follow-through after contact can be used to decrease head acceleration. Additionally, improvements in symmetric neck flexor and extensor strength and neuromuscular neck stiffness can decrease head acceleration. Head-to-head impacts and unanticipated ball contacts result in the highest head acceleration. Ball contacts at high velocity may also be dangerous. The risk of concussive impacts may be lessened through the use of headgear, but headgear may also cause athletes to play more recklessly because they feel a sense of increased security. Young, but physically capable, athletes should be taught proper heading technique in a controlled setting, using a carefully planned progression of the skill.

  5. 14 CFR 25.1435 - Hydraulic systems.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hydraulic systems. 25.1435 Section 25.1435... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1435 Hydraulic systems. (a) Element design. Each element of the hydraulic system must be designed to: (1) Withstand the proof...

  6. 14 CFR 27.1435 - Hydraulic systems.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hydraulic systems. 27.1435 Section 27.1435... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Safety Equipment § 27.1435 Hydraulic systems. (a) Design. Each hydraulic system and its elements must withstand, without yielding, any structural loads...

  7. Sex differences in head acceleration during heading while wearing soccer headgear.

    Tierney, Ryan T; Higgins, Michael; Caswell, Shane V; Brady, Jessica; McHardy, Krista; Driban, Jeffrey B; Darvish, Kurosh


    Researchers have indicated that female soccer players may be at greater risk of concussion compared with their male counterparts. Soccer headgear is marketed for reducing head acceleration and risk of concussion. To determine the effect of sex and soccer headgear on head impact kinematics and dynamic stabilization during soccer heading. Cross-sectional design. Research laboratory. Forty-four college-aged soccer players (29 women, 15 men). Using a head impact model, participants performed 4 soccer headers under 3 headgear conditions (control, Head Blast Soccer Band, and Full90 Select Performance Headguard). Dependent variables assessed before soccer heading were head-neck anthropometrics and isometric neck muscle strength, and those assessed during soccer headers were resultant linear head acceleration, Head Injury Criteria (HIC(36)), and superficial neck muscle electromyography. Statistical analyses included multivariate and univariate analyses of variance with repeated measures, independent-samples t tests, appropriate follow-up analyses of variance and post hoc t tests, and Pearson product moment correlations (alpha = .05). Head acceleration in women was 32% and 44% greater than in men when wearing the Head Blast (21.5 g versus 16.3 g) and Full90 Select (21.8 g versus 15.2 g), respectively (P head accelerations (20.2 g versus 18.2 g) during the control condition (P = .164). Female soccer players exhibited greater head accelerations than their male counterparts when wearing headgear. Our results are important clinically because they indicate that soccer headgear may not be an appropriate head injury prevention tool for all athletes.

  8. Review on hidden trouble detection and health diagnosis of hydraulic concrete structures

    WU; ZhongRu; LI; Ji; GU; ChongShi; SU; HuaiZhi


    A large number of hydraulic concrete structures have hidden defects such as cracks,erosion,freeze and thaw,thermal fatigue,carbonization.These hidden defects seriously affect the strength,stability and durability of structures.These problems are studied mainly by single monitoring or diagnosis methods at present.The integration of multiple monitoring and diagnosis methods is not applied widely.Besides,the analysis theory on these problems is not developed very well.The systemic study on the aging mechanism of hydraulic concrete structures,timevariation model and health diagnosis is still not enough.The support for engineering practice is limited.Aimed at these major scientific and technological problems and combined with specific projects,study on detection of hidden defects and health diagnosis of hydraulic concrete structure has been carried out.This study includes the following content: field non-destructive examination of hidden defects of hydraulic concrete structures,seepage detection,the construction of in-situ sensing system,the combination of field detection and in-situ monitoring,the mechanism of crack,freeze and thaw,erosion and carbonization of hydraulic concrete structure,mechanism of combination aging; time-variation model of hydraulic concrete structure,theories and methods for health diagnosis of hydraulic concrete structures.

  9. HT300高强度缸体缸盖材料熔炼技术研究%A Study on Melting Technique of HT300-Grade Hi-Strength Gray Iron for Cylinder Blocks and Heads



    The influences of melting process, carbon and silicon, manganese and sulphur, alloying and inoculation on molten iron quality of hi-strength gray irons were analyzed. It is considered that using pig iron in large fraction would increase shrinkage tendency of the molten iron and decrease properties of castings; selection of carburizing agent is the key of melting with full steel scrap charge; it is necessary, in order to produce hi-strength gray iron castings with relatively high carbon and silicon content, to take measures to increase graphite nuclei in the melting process and, at the same time, increase sulphur content to prevent the graphite from growing into coarse flakes; proper alloying and inoculation can obviously decrease the shrinkage tendency of the molten iron. It was pointed out that, by delaying knock out to let castings slowly cool in moulds, it is possible to eliminate casting stress and to offer the last guarantee for producing hi-quality castings.%分析了熔炼工艺、碳硅成分,锰硫成分、合金化及孕育处理对高强度灰铸铁铁液质量的影响,认为大量使用生铁使铁液收缩倾向增大且使铸件性能降低;增碳剂的选用是全废钢熔炼的关键;在较高碳硅含量条件下生产高强度灰铸铁件,必须设法在熔炼过程中增加石墨晶核,并增硫防止石墨长成粗大片状;适当的合金化和孕育处理,可以使铁液的收缩倾向得到明显改善.指出可以通过延迟开箱时间使铸件在砂箱中缓慢冷却以消除铸造应力,为生产优质铸件提供最后保证.

  10. The unsaturated hydraulic characteristics of the Bandelier Tuff

    Rogers, D.B.; Gallaher, B.M.


    This report summarizes the physical and, unsaturated hydraulic properties of the Bandelier Tuff determined from laboratory measurements made on core samples collected at Los Alamos National Laboratory. We fit new van Genuchten-type moisture retention curves to this data, which was categorized according to member of the Bandelier Tuff and subunit of the Tshirege Member. Reasonable consistency was observed for hydraulic properties and retention curves within lithologic units, while distinct differences were observed for those properties between units. With the moisture retention data, we constructed vertical profiles of in situ matric suction and hydraulic head. These profiles give an indication of the likely direction of liquid water movement within the unsaturated zone and allow comparison of core-scale and field-scale estimates of water flow and solute transport parameters. Our core-derived transport velocities are much smaller than values estimated from tritium, Cl, and NO{sub 3} contamination found recently in boreholes. The contaminant tracer-derived transport velocities from Los Alamos Canyon are greater than corederived values found for the Otowi Member, and for Mortandad Canyon, greater than core-derived values for that borehole. The significant difference found for Mortandad Canyon suggests that fracture or other fast-path transport may be important there. The relatively small difference between observed and predicted velocities at Los Alamos Canyon may mean that vadose zone transport there occurs by unsaturated matrix flow.




    Full Text Available The paper presents methodology used for determining the efficiency of a low head Kaplan hydraulic turbine with short converging intake. The measurement method used was the current meters method, the only measurement method recommended by the IEC 41standard for flow measurement in this case. The paper also presents the methodology used for measuring the flow by means of the current meters method and the various procedures for calculating the flow. In the last part the paper presents the flow measurements carried out on the Fughiu HPP hydraulic turbines for determining the actual operating efficiency.

  12. Thermal Hydraulic Performance of Tight Lattice Bundle

    Yamamoto, Yasushi; Akiba, Miyuki; Morooka, Shinichi; Shirakawa, Kenetsu; Abe, Nobuaki

    Recently, the reduced moderation spectrum BWR has been studied. The fast neutron spectrum is obtained through triangular tight lattice fuel. However, there are few thermal hydraulic test data and thermal hydraulic correlation applicable to critical power prediction in such a tight lattice bundle. This study aims to enhance the database of the thermal hydraulic performance of the tight lattice bundle whose rod gap is about 1mm. Therefore, thermal hydraulic performance measurement tests of tight lattice bundles for the critical power, the pressure drop and the counter current flow limiting were performed. Moreover, the correlations to evaluate the thermal-hydraulic performance of the tight lattice bundle were developed.

  13. Design of hydraulic output Stirling engine

    Toscano, W. M.; Harvey, A. C.; Lee, K.


    A hydraulic output system for the RE-1000 free piston stirling engine (FPSE) was designed. The hydraulic output system can be readily integrated with the existing hot section of RE-1000 FPSE. The system has two simply supported diaphragms which separate the engine gas from the hydraulic fluid, a dynamic balance mechanism, and a novel, null center band hydraulic pump. The diaphragms are designed to endure more than 10 billion cycles, and to withstand the differential pressure load as high as 14 MPa. The projected thermodynamic performance of the hydraulic output version of RE-1000 FPSE is 1.87 kW at 29/7 percent brake efficiency.

  14. Impacts of bedding directions of shale gas reservoirs on hydraulically induced crack propagation

    Keming Sun


    Full Text Available Shale gas reservoirs are different from conventional ones in terms of their bedding architectures, so their hydraulic fracturing rules are somewhat different. In this paper, shale hydraulic fracturing tests were carried out by using the triaxial hydraulic fracturing test system to identify the effects of natural bedding directions on the crack propagation in the process of hydraulic fracturing. Then, the fracture initiation criterion of hydraulic fracturing was prepared using the extended finite element method. On this basis, a 3D hydraulic fracturing computation model was established for shale gas reservoirs. And finally, a series of studies were performed about the effects of bedding directions on the crack propagation created by hydraulic fracturing in shale reservoirs. It is shown that the propagation rules of hydraulically induced fractures in shale gas reservoirs are jointly controlled by the in-situ stress and the bedding plane architecture and strength, with the bedding direction as the main factor controlling the crack propagation directions. If the normal tensile stress of bedding surface reaches its tensile strength after the fracturing, cracks will propagate along the bedding direction, and otherwise vertical to the minimum in-situ stress direction. With the propagating of cracks along bedding surfaces, the included angle between the bedding normal direction and the minimum in-situ stress direction increases, the fracture initiation and propagation pressures increase and the crack areas decrease. Generally, cracks propagate in the form of non-plane ellipsoids. With the injection of fracturing fluids, crack areas and total formation filtration increase and crack propagation velocity decreases. The test results agree well with the calculated crack propagation rules, which demonstrate the validity of the above-mentioned model.

  15. A Laboratory Study of the Effects of Interbeds on Hydraulic Fracture Propagation in Shale Formation

    Zhiheng Zhao


    Full Text Available To investigate how the characteristics of interbeds affect hydraulic fracture propagation in the continental shale formation, a series of 300 mm × 300 mm × 300 mm concrete blocks with varying interbeds, based on outcrop observation and core measurement of Chang 7-2 shale formation, were prepared to conduct the hydraulic fracturing experiments. The results reveal that the breakdown pressure increases with the rise of thickness and strength of interbeds under the same in-situ field stress and injection rate. In addition, for the model blocks with thick and high strength interbeds, the hydraulic fracture has difficulty crossing the interbeds and is prone to divert along the bedding faces, and the fracturing effectiveness is not good. However, for the model blocks with thin and low strength interbeds, more long branches are generated along the main fracture, which is beneficial to the formation of the fracture network. What is more, combining the macroscopic descriptions with microscopic observations, the blocks with thinner and lower strength interbeds tend to generate more micro-fractures, and the width of the fractures is relatively larger on the main fracture planes. Based on the experiments, it is indicated that the propagation of hydraulic fractures is strongly influenced by the characteristics of interbeds, and the results are instructive to the understanding and evaluation of the fracability in the continental shale formation.

  16. Introduction of Explosive Cladding Technology for the Manufacturing of Hydraulic Cylinders

    Jovišević, V.; M. Soković; B. Kosec


    The microhardness, microstructure and bond strength of the interface of a bi-metallic joint on the cross-section of the testing hydraulic cylinder were investigated. Experimental findings of related to both method of cladding obtained with metallographic and mechanical investigations of the interface between the CuSn6 bronze and the TS5 (Č.1213) steel cylinder, are given.

  17. Hydraulic fracture during epithelial stretching

    Casares, Laura; Vincent, Romaric; Zalvidea, Dobryna; Campillo, Noelia; Navajas, Daniel; Arroyo, Marino; Trepat, Xavier


    The origin of fracture in epithelial cell sheets subject to stretch is commonly attributed to excess tension in the cells’ cytoskeleton, in the plasma membrane, or in cell-cell contacts. Here, we demonstrate that for a variety of synthetic and physiological hydrogel substrates the formation of epithelial cracks is caused by tissue stretching independently of epithelial tension. We show that the origin of the cracks is hydraulic; they result from a transient pressure build-up in the substrate during stretch and compression manoeuvres. After pressure equilibration, cracks heal readily through actomyosin-dependent mechanisms. The observed phenomenology is captured by the theory of poroelasticity, which predicts the size and healing dynamics of epithelial cracks as a function of the stiffness, geometry and composition of the hydrogel substrate. Our findings demonstrate that epithelial integrity is determined in a tension-independent manner by the coupling between tissue stretching and matrix hydraulics.

  18. Bio-based Hydraulic Fluids


    currently formulated with vegetable oils (i.e., rapeseed , sun flower, corn, soybean, canola, coconut, etc.) and synthetic ester, such as polyol ester...2008 Vegetable Oil • Excellent lubrication • Nontoxic • Biodegradable • Derived from renewable resources such as rapeseed , sunflower, corn...Mineral Oil 100 SAE 15W-40 G Rapeseed 32 Commercial HF H Polyol ester 22 MIL-PRF-32073 Grade 2 I Canola - Cooking Oil *Hydraulic fluid 3717 April

  19. Fire Resistant Aircraft Hydraulic System.


    and compounds based on new experimental elastomers as well as most commercially available elastomers were screened in seeking seals that were both...for hydraulic component testing. All of the available E6.5 stock was purchased for the screening tests. However, DuPont stated that other homologs of...with the lubricity and anti-wear additive olyvan A (molybdenum oxysulphide dithiocarbamate ) added in the quantity of less than one percent by weight


    V. V. Ivashechkin


    Full Text Available The article offers design of a hydraulic elevator installation for cleaning up water-source wells of sand packs. It considerers the installation hydraulic circuit according to which the normal pump feeds the high-level tank water into the borehole through two parallel water lines. The water-jet line with washing nozzle for destroying the sand-pack and the supply pipe-line coupled with the operational nozzle of the hydraulic elevator containing the inlet and the supply pipelines for respectively intaking the hydromixture and removing it from the well. The paper adduces equations for fluid motion in the supply and the water-jet pipelines and offers expressions for evaluating the required heads in them. For determining water flow in the supply and the water-jet pipe lines the author proposes to employ graphical approach allowing finding the regime point in Q–H chart by means of building characteristics of the pump and the pipe-lines. For calculating the useful vertical head, supply and dimensions of the hydraulic elevator the article employs the equation of motion quantity with consistency admission of the motion quantity before and after mixing the flows in the hydraulic elevator. The suggested correlations for evaluating the hydraulic elevator efficiency determine the sand pack removal duration as function of its sizes and the ejected fluid flow rate. A hydraulic-elevator installation parameters estimation example illustrates removing a sand pack from a water-source borehole of 41 m deep and 150 mm diameter bored in the village of Uzla of Myadelsk region, of Minsk oblast. The working efficiency of a manufactured and laboratory tested engineering prototype of the hydraulic elevator installation was acknowledged in actual tests at the indicated borehole site. With application of graphical approach, the suggested for the hydraulic elevator installation parameters calculation procedure allows selecting, with given depth and the borehole diameter

  1. Determination and discussion hydraulic retention time in membrane bioreactor system


    Based on the microorganism kinetic model, the formulafor computing hydraulic retention time in a membrane bioreactorsystem (MBR) is derived. With considering HRT as an evaluationindex a combinational approach was used to discuss factors whichhave an effect on MBR. As a result, the influencing factors werelisted in order from strength to weakness as: maximum specificremoval rate K, saturation constant Ks, maintenance coefficient m,Moreover, the formula was simplified, whose parameters wereexperimentally determined in petrochemical wastewater treatment. The simplified formula is (=1.1((1/(-1)(Ks+S)/KX0, forpetrochemical wastewater treatment K and Ks equaled 0.185 and154.2, respectively.

  2. Experimental Study about Activated Water Generated by the Electro-hydraulic Impulse Strengthening the Mechanical Performance of Concrete


    On the basis of a great number of experiments, it is proved that the strength of concrete is improved greatly when it is mixed with activated water produced by the electro-hydraulic impulse. With the proper parameters, the compression strength of concrete can be increased by 45%. The reason for improvement of concrete strength by using activated water is discussed from the aspect of the structure of molecule.

  3. SEISM SAFETY OF PRESSURE HEAD HYDRAULIC ENGINEERING CONSTRUCTIONS Сейсмобезопасность напорных гидротехнических сооружений

    Volosoukhin V. A.


    Full Text Available Experience of supervision of safety of the hydraulic engineering constructions, operating in our country since 1971, and the first 15 years of the Federal law of the Russian Federation No. 117-FZ from 21.07.1997 “About safety of hydraulic engineering constructions”, when persons under surveillance of GTS steel of power, the industry and a water economic complex is given. The majority (97 % potentially dangerous GTS of the Russian Federation treat the IV class of solidity with service life from 40 to 50 and more years where, as a rule, is absent or the operation service, insufficient quantity of instrumentation is small. Monitoring of a technical condition of similar GTS is possible with use of the mobile, mobile complexes equipped with the modern equipment (hydrological, geophysical, geodetic, mechanical, etc.. Safety of GTS is in many respects caused by a skill level of the operational personnel. For the solution of questions of increase of their safety amending the current legislation is necessary

  4. Hydraulic Redistribution: A Modeling Perspective

    Daly, E.; Verma, P.; Loheide, S. P., III


    Roots play a key role in the soil water balance. They extract and transport water for transpiration, which usually represents the most important soil water loss in vegetated areas, and can redistribute soil water, thereby increasing transpiration rates and enhancing root nutrient uptake. We present here a two-dimensional model capable of describing two key aspects of root water uptake: root water compensation and hydraulic redistribution. Root water compensation is the ability of root systems to respond to the reduction of water uptake from areas of the soil with low soil water potential by increasing the water uptake from the roots in soil parts with higher water potential. Hydraulic redistribution is a passive transfer of water through the root system from areas of the soil with greater water potential to areas with lower water potential. Both mechanisms are driven by gradients of water potential in the soil and the roots. The inclusion of root water compensation and hydraulic redistribution in models can be achieved by describing root water uptake as a function of the difference in water potential between soil and root xylem. We use a model comprising the Richards equation for the water flow in variably saturated soils and the Darcy's equation for the water flow in the xylem. The two equations are coupled via a sink term, which is assumed to be proportional to the difference between soil and xylem water potentials. The model is applied in two case studies to describe vertical and horizontal hydraulic redistribution and the interaction between vegetation with different root depths. In the case of horizontal redistribution, the model is used to reproduce the fluxes of water across the root system of a tree subjected to uneven irrigation. This example can be extended to situations when only part of the root system has access to water, such as vegetation near creeks, trees at the edge of forests, and street trees in urban areas. The second case is inspired by recent

  5. Development of 30Cr06A, a high strength cast steel and its welding ability

    GAO You-jin


    High performance hydraulic supports have a high requirement in strength, toughness and welding ability of socket ma- terial. Targeting this problem, we analyzed the properties of the high strength socket material 30Cr06, used in high performance hydraulic supports both at home and abroad and developed a new kind of high strength cast steel 30Cr06A, by making use of an orthogonal experiment, which provided the design conditions for its optimal composition. The result shows that the strength and toughness of the newly developed high strength cast steel 30Cr06A is much better than that of 30Cr06. Theoretical calculations, mechanical property tests and hardness distribution tests of welded joints were carried out for a study of the welding ability of the new material, which is proved to be very good. Therefore, this 30Cr06A material has been successfully used in the socket of high performance hydraulic support.

  6. A mini slug test method for determination of a local hydraulic conductivity of an unconfined sandy aquifer

    Hinsby, Klaus; Bjerg, Poul Løgstrup; Andersen, Lars J.;


    from level to level and thereby establish vertical profiles of the hydraulic conductivity. The head data from the test well are recorded with a 10 mm pressure transducer, and the initial head difference required is established by a small vacuum pump. The method described has provided 274 spatially......A new and efficient mini slug test method for the determination of local hydraulic conductivities in unconfined sandy aquifers is developed. The slug test is performed in a small-diameter (1 inch) driven well with a 0.25 m screen just above the drive point. The screened drive point can be driven...... distributed measurements of a local hydraulic conductivity at a tracer test site at Vejen, Denmark. The mini slug test results calculated by a modified Dax slug test analysing method, applying the elastic storativity in the Dax equations instead of the specific yield, are in good accordance with the results...

  7. Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at the Indian Point Energy Center, Buchanan, New York

    Williams, John H.


    Flow logs from 24 test wells were analyzed as part of the hydraulic characterization of the metamorphosed and fractured carbonate bedrock at the Indian Point Energy Center in Buchanan, New York. The flow logs were analyzed along with caliper, optical- and acoustic-televiewer, and fluid-resistivity and temperature logs to determine the character and distribution of fracture-flow zones and estimate their transmissivities and hydraulic heads. Many flow zones were associated with subhorizontal to shallow-dipping fractured zones, southeast-dipping bedding fractures, northwest-dipping conjugate fractures, or combinations of bedding and conjugate fractures. Flow-log analysis generally provided reasonable first-order estimates of flow-zone transmissivity and head differences compared with the results of conventional hydraulic-test analysis and measurements. Selected results of an aquifer test and a tracer test provided corroborating information in support of the flow-log analysis.

  8. Computed Tomography (CT) -- Head

    Full Text Available ... limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, more ... the body being studied. top of page How is the procedure performed? The technologist begins by positioning ...

  9. Designing of Hydraulically Balanced Water Distribution Network Based on GIS and EPANET

    RASOOLI Ahmadullah


    Full Text Available The main objectives of this paper are, designing and balancing of Water Distribution Network (WDN based on loops hydraulically balanced method as well as using Geographical Information System (GIS methodology with the contribution of EPANET. GIS methodology is used to ensure WDN’s integrity and skeletonized a proper and functional WDN by using Network Analyst utilizing the geometric network and topology network by hierarchical geo-databases. The problem is to make WDN hydraulically balanced by applying WDN balancing method. For that reason, we have analyzed water flows in each pipe and performed the iterations process on loops in order to make the algebraic summation of head loss“h_f” around any closed loop zero. In case, the summation of pipe flows must be equal to the flow amount entering or leaving the system through each node. At each iteration, reasonable changes occurred at pipes flow until the head loss has become very small or fixed zero as (optimizes correction by using excel sheet solver. Since this method is confirmed to be effective, simulations were done by using GIS and EPANET water distribution platform. As a result, we accomplished hydraulically balanced WDN. Finally, we have analyzed and simulated hydraulics parameters for the targeted area in Kabul city. Thus, determined successfully the hydraulics state of parameters around the network as a positive result. It is worth mentioning that, Hardy-cross method is being used for approaching more precise optimized correction and consequences concerning hydraulically-balanced and optimal WDN. This method can be done for complex loops WDN as well; the advantage of the method is simple math and self-correction. Managers and engineers who work in the field of water supply this methodology has been recommended as the more advantageous workflow in planning water distribution pattern.

  10. Experimental investigation of the dielectric properties of soil under hydraulic loading

    Bittner, Tilman; Bore, Thierry; Wagner, Norman; Karlovšek, Jurij; Scheuermann, Alexander


    An experimental set-up was developed in order to determine the coupled hydraulic, dielectric and mechanical properties of granular media under hydraulic loading. The set-up consisted of a modified column for permeability tests involving a flow meter and pressure transducers along the sample to quantify the hydraulic gradient. A newly developed open-ended coaxial probe allowed the measurement of the frequency dependent dielectric permittivity of the material under test. The shear strength of the sample within the column was measured using a conventional vane shear device. In this paper, the overall set-up is introduced with focus on the open-ended coaxial probe. The design and calibration of the probe are introduced in detail. A numerical study showed that the sensitive cylindrical volume of the probe was approximately 150 mm in diameter with a depth of 65 mm. An investigation with glass beads showed that the set-up allowed the parameterization of the hydraulic, mechanic and dielectric parameters of granular materials under the influence of vertical flow. A satisfactorily good correlation between porosity and the real part of the dielectric permittivity was detected. The critical hydraulic gradient defining the transition of a fixed bed of particles to fluidization was characterized by a sharp peak in the evolution of the hydraulic conductivity and could easily be determined from the measurements. The shear strength of the material under test reduces linearly with increasing hydraulic gradient. Future investigations will be carried out to provide the required parameterizations for experimental and numerical investigations of the internal erosion of granular media.

  11. Vibrations of hydraulic pump and their solution

    Dobšáková Lenka; Nováková Naděžda; Habán Vladimír; Hudec Martin; Jandourek Pavel


    The vibrations of hydraulic pump and connected pipeline system are very problematic and often hardly soluble. The high pressure pulsations of hydraulic pump with the double suction inlet are investigated. For that reason the static pressure and accelerations are measured. The numerical simulations are carried out in order to correlate computed data with experimental ones and assess the main source of vibrations. Consequently the design optimization of the inner hydraulic part of pump is done ...

  12. Temporal changes in hydraulic conductivity of sand porous media biofilters during wastewater infiltration due to biomat formation

    Beach, Deborah N. H.; McCray, John E.; Lowe, Kathryn S.; Siegrist, Robert L.


    Porous media biofilters (PMBs) are commonly used to treat domestic wastewater. Biomats develop at the infiltrative surface of PMBs due to continued wastewater application and create an impedance to flow. The goal of this research is to quantify the temporal evolution of normalized biomat hydraulic conductivity ( Kbm/ bbm) and effective hydraulic conductivity ( Ke). Ke is the overall hydraulic conductivity of the infiltrative zone, including biomat and unsaturated media below the biomat. Research was conducted using eight one-dimensional (1D) sand columns with gravel-free and gravel-laden infiltrative surfaces. The columns were loaded at design rates of 100-200 cm/d for 20 weeks of column operation. The Ke values for these continuously loaded columns were determined from analyses of bromide-tracer tests, falling-head permeability tests, and volumetric water content measurements during biomat development. The reduction in the Ke due to biomat formation is due to two factors: reduced hydraulic conductivity of the thin biomat, and a reduced hydraulic conductivity of the subsoil due to development of a biomat-induced unsaturated flow regime. Unsaturated hydraulic conductivities of the subsoil below the biomat ( Kss) were estimated from capillary curves and water content measurements. For observed final biomat thicknesses (less than 1 cm), the biomat hydraulic conductivity, Kbm, is three orders of magnitude smaller than the unsaturated hydraulic conductivity ( Kss). However, the relatively large thickness of the vadose zone causes the Kss to be an important contributor to the overall Ke value. For these columns, the final Ke values were approximately two orders of magnitude smaller than the original value. Because the exact thickness of the biomat ( bbm) is unknown during the flow experiments, the hydraulic conductance of the biomat zone is presented using a normalized hydraulic conductivity function ( Kbm/ bbm). A similar Kbm/ bbm is reached regardless of wastewater

  13. Hydraulic properties of typical salt-affected soils in Jiangsu Province,China

    CHEN Xiaomin; SHEN Qirong; XU Yangchun


    Every year about 1,500 ha of land is reclaimed from the sea along the coastline of Jiangsu Province,China.It is important to characterize the hydraulic properties of this reclaimed land to be able to predict and manage salt and water movement for amelioration of these saline soils.In this paper,we report hydraulic properties of these salt-affected soils.The pressure-plate method,constant head method,the crust method and Klute's method were used in this study.The satu rated hydraulic conductivities of the soils ranged from 128.66 to 141.26 cm/day and decreased with increasing soil depth.The unsaturated hydraulic conductivities followed an expo nential function of pressure head.The soil water retention curves were similar for three soil layers in the soil.The satu rated water content,field capacity and wilting point decreased with increasing soil depth.Plant available water contents of the three layers in the soil profile were 0.21,0.20 and 0.19 cm3/cm3,respectively.The unsaturated soil water diffu sivity of the studied soils ranged from 0.07 to 10.46 cm2/min,and was related to the water content via an exponential relationship.

  14. Effects of biochars on hydraulic properties of clayey soil

    Zhen, Jingbo; Palladino, Mario; Lazarovitch, Naftali; Bonanomi, Giuliano; Battista Chirico, Giovanni


    Biochar has gained popularity as an amendment to improve soil hydraulic properties. Since biochar properties depend on feedstocks and pyrolysis temperatures used for its production, proper selection of biochar type as soil amendment is of great importance for soil hydraulic properties improvement. This study investigated the effects of eight types of biochar on physical and hydraulic properties of clayey soil. Biochars were derived from four different feedstocks (Alfalfa hay, municipal organic waste, corn residues and wood chip) pyrolyzed at two different temperatures (300 and 550 °C). Clayey soil samples were taken from Leone farm (40° 26' 15.31" N, 14° 59' 45.54" E), Italy, and were oven-dried at 105 °C to determine dry bulk density. Biochars were mixed with the clayey soil at 5% by mass. Bulk densities of the mixtures were also determined. Saturated hydraulic conductivities (Ks) of the original clayey soil and corresponding mixtures were measured by means of falling-head method. Soil water retention measurements were conducted for clayey soil and mixtures using suction table apparatus and Richards' plate with the pressure head (h) up to 12000 cm. van Genuchten retention function was selected to evaluate the retention characteristics of clayey soil and mixtures. Available water content (AWC) was calculated by field capacity (h = - 500 cm) minus wilting pointing (h = -12000 cm). The results showed that biochar addition decreased the bulk density of clayey soil. The Ks of clayey soil increased due to the incorporation of biochars except for waste and corn biochars pyrolyzed at 550 °C. AWC of soils mixed with corn biochar pyrolyzed at 300 °C and wood biochar pyrolyzed at 550 °C, increased by 31% and 7%, respectively. Further analysis will be conducted in combination of biochar properties such as specific surface area and total pore volume. Better understanding of biochar impact on clayey soil will be helpful in biochar selection for soil amendment and

  15. Hydraulically Driven Grips For Hot Tensile Specimens

    Bird, R. Keith; Johnson, George W.


    Pair of grips for tensile and compressive test specimens operate at temperatures up to 1,500 degrees F. Grips include wedges holding specimen inside furnace, where heated to uniform temperature. Hydraulic pistons drive wedges, causing them to exert clamping force. Hydraulic pistons and hydraulic fluid remain outside furnace, at room temperature. Cooling water flows through parts of grips to reduce heat transferred to external components. Advantages over older devices for gripping specimens in high-temperature tests; no need to drill holes in specimens, maintains constant gripping force on specimens, and heated to same temperature as that of specimen without risk of heating hydraulic fluid and acuator components.

  16. Veining Failure and Hydraulic Fracturing in Shales

    Mighani, S.; Sondergeld, C. H.; Rai, C. S.


    During the hydraulic fracturing, the pressurized fluid creates new fractures and reactivates existing natural fractures forming a highly conductive Stimulated Reservoir Volume (SRV) around the borehole. We extend the previous work on Lyons sandstone and pyrophyllite to anisotropic shale from the Wolfcamp formation. We divide the rock anisotropy into two groups: a) conventional and b) unconventional (shaly) anisotropy. X-ray Computed Tomography (CT), compressional velocity anisotropy, and SEM analysis are used to identify three causes of anisotropy: bedding planes, clay lamination, and calcite veins. Calcite vein is a subsequently filled with calcite bonded weakly to the matrix. Velocity anisotropy and visual observations demonstrate the calcite filled veins to be mostly subparallel to the fabric direction. Brazilian tests are carried out to observe the fracture initiation and propagation under tension. High speed photography (frame rate 300,000 frame/sec) was used to capture the failure. Strain gauges and Acoustic Emission (AE) sensors recorded the deformation leading up to and during failure. SEM imaging and surface profilometry were employed to study the post-failure fracture system and failed surface topology. Fracture permeability was measured as a function of effective stress. Brazilian tests on small disks containing a centered single vein revealed the shear strength of the veins. We interpret the strain data and number, frequency, and amplitude of AE events which are correlated well with the observed fracture process zone, surface roughness, and permeability. The unpropped fracture has enhanced permeability by two orders of magnitude. The observed anisotropic tensile failure seems to have a universal trend with a minimum strength occurring at 15o orientation with respect to the loading axis. The veins at 15o orientation with respect to the loading axis were easily activated at 30% of the original failure load. The measured strength of the vein is as low as 6

  17. Design and Analysis of Hydraulic Chassis with Obstacle Avoidance Function

    Hong, Yingjie; Zhang, Xiang


    This article mainly expounds the design of hydraulic system for the hydraulic chassis with obstacle avoidance function. Including the selection of hydraulic motor wheels, hydraulic pump, digital hydraulic cylinder and the matching of engine power. And briefly introduces the principle of obstacle avoidance.

  18. Integration of Tracer Test Data to Refine Geostatistical Hydraulic Conductivity Fields Using Sequential Self-Calibration Method

    Bill X Hu; Jiang Xiaowei; Wan Li


    On the basis of local measurements of hydraulic conductivity, geostatistical methods have been found to be useful in heterogeneity characterization of a hydraulic conductivity field on a regional scale. However, the methods are not suited to directly integrate dynamic production data, such as,hydraulic head and solute concentration, into the study of conductivity distribution. These data, which record the flow and transport processes in the medium, are closely related to the spatial distribution of hydraulic conductivity. In this study, a three-dimensional gradient-based inverse method-the sequential self-calibration (SSC) method-is developed to calibrate a hydraulic conductivity field,initially generated by a geostatistical simulation method, conditioned on tracer test results. The SSC method can honor both local hydraulic conductivity measurements and tracer test data. The mismatch between the simulated hydraulic conductivity field and the reference true one, measured by its mean square error (MSE), is reduced through the SSC conditional study. In comparison with the unconditional results, the SSC conditional study creates the mean breakthrough curve much closer to the reference true curve, and significantly reduces the prediction uncertainty of the solute transport in the observed locations. Further, the reduction of uncertainty is spatially dependent, which indicates that good locations, geological structure, and boundary conditions will affect the efficiency of the SSC study results.

  19. Micro-process model of hydraulic shock absorber with abnormal structural noise


    In order to discover the causes of the abnormal noise of shock absorbers,it is necessary to identify the operating characteristics of the shock absorbers.A micro-process model for operation of the hydraulic shock absorber was presented.A novel concept,which describes the process of hydraulic shock absorber by dividing it into smaller steps,was proposed.The dynamic model and the differential equations were established.The results of numerical simulation agree well with data obtained from the vibrostand test,indicating that the collision between the piston and the oil,the alternation of static friction and sliding friction acted between the piston and the cylinder,and the adherence between valve plate and piston result in impact on the piston head near the top dead center and the bottom dead center.Ultimately,the impact excites the high-frequency vibration of the piston structure,which can generate the abnormal noise in the hydraulic shock absorber after its transfer.And the maximum vibration acceleration on the piston head and the abnormal noise increase with the increase of the gap between the oil and piston rod head,the maximum static friction force and the adhering function,respectively.

  20. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses ... of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical ...

  1. Helical coil thermal hydraulic model

    Caramello, M.; Bertani, C.; De Salve, M.; Panella, B.


    A model has been developed in Matlab environment for the thermal hydraulic analysis of helical coil and shell steam generators. The model considers the internal flow inside one helix and its associated control volume of water on the external side, both characterized by their inlet thermodynamic conditions and the characteristic geometry data. The model evaluates the behaviour of the thermal-hydraulic parameters of the two fluids, such as temperature, pressure, heat transfer coefficients, flow quality, void fraction and heat flux. The evaluation of the heat transfer coefficients as well as the pressure drops has been performed by means of the most validated literature correlations. The model has been applied to one of the steam generators of the IRIS modular reactor and a comparison has been performed with the RELAP5/Mod.3.3 code applied to an inclined straight pipe that has the same length and the same elevation change between inlet and outlet of the real helix. The predictions of the developed model and RELAP5/Mod.3.3 code are in fairly good agreement before the dryout region, while the dryout front inside the helical pipes is predicted at a lower distance from inlet by the model.

  2. Investigation of anistropic behavior of Montney Shale under indirect tensile strength test

    Keneti, S.A.R.; Wong, R.C.K. [Calgary Univ., Calgary, AB (Canada)


    The Montney Shale Formation is located near the British Columbia and Alberta borders and is one of the largest economically feasible resource plays in North America. Hydraulic fracturing is used to enhance the gas production. Initiation and propagation of hydraulically induced fracture is controlled by in-situ stresses magnitude and orientation and the reservoir tensile strength. The tensile strength becomes one of the most important parameters in governing hydraulic fracturing of the reservoir if the in-situ stresses composing one vertical and two horizontal stresses are comparable or lie within a narrow range. Different point and line load tests were used in this study to determine the tensile strength of Montney shale cores in two perpendicular directions. The paper discussed image analysis of Montney shale cores and tensile strength tests, including Brazilian tests for measuring tensile strength in the horizontal direction and point load tests for measuring tensile strength in the vertical direction. The effect of anisotropic tensile strength on hydraulic fracturing of Montney shale was also presented. It was concluded from the test results that the Montney shale exhibits a high anisotropy in tensile strength. 11 refs., 3 tabs., 11 figs.

  3. Aired-time and chamotte hydraulic mortars

    González Cortina, M.


    Full Text Available The aim of this research project has been to obtain aired-li me based hydraulic mortars with the addition of chamotte or burnt clay powder obtained from the ceramic industry waste. By doing this, hydraulic properties have been included into lime and hydraulic mortars with a great improvement in mechanical properties. In order to achieve this, different types of chamotte obtained from clay burnt at different temperatures have been tested, changing, at the same time, the proportions of lime, sand, chamotte and water. All the tests have been performed preparing a double set of test pieces to be kept at room temperature or to be immersed in water, determining the Shore C hardness and the mechanical compressive and tensile strengths. Further on, X-ray diffraction analysis have been developed to determine the qualitative composition of the crystalline structure, as well as micro structural analysis, using stereomicroscope and electric microscope scanning, with X-ray microanalysis have been used. As a conclusion, several types of mortars have been created with different proportions, which can be used, due to its characteristics, as keying mortars in brickwork, for restoration works as well as for new constructions.

    El objetivo de éste trabajo es el conseguir morteros hidráulicos, a partir de la cal aérea, con adición de chamota o polvo de arcilla cocida, obtenida de los residuos-desechos de la industria cerámica. De este modo se pretende infundir propiedades hidráulicas a la cal y obtener morteros hidráulicos, con una mejora sustancial de sus propiedades mecánicas. Para ello, se ha experimentado con diversos tipos de chamotas, obtenidas a partir de arcillas cocidas a diferentes temperaturas, y con diversas granulometrías, y se han realizado morteros con distintas dosificaciones, variando las proporciones de cal, arena, chamota y agua. En todos los casos se ha preparado una doble serie de probetas, para conservarlas al aire o


    CHEN Yun-liang; WU Chao; YE Mao; JU Xiao-ming


    The trace of vertical vortex flow at hydraulic intakes is of the shape of spiral lines, which was observed in the presented experiments with the tracer technique. It represents the fluid particles flow spirally from the water surface to the underwater and rotate around the vortex-axis multi-cycle. This process is similar to the movement of screw. To describe the multi-circle spiral characteristics under the axisymmetric condition, the vertical vortex would change not only in the radial direction but also in the axial direction. The improved formulae for three velocity components for the vertical vortex flow were deduced by using the method of separation of variables in this article. In the improved formulae, the velocity components are the functions of the radial and axial coordinates, so the multi-circle spiral flow of vertical vortex could be simulated. The calculated and measured results for the vertical vortex flow were compared and the causes of errors were analyzed.

  5. Hydroscoop - Bulletin of the small-scale hydraulic laboratory MHyLab; Hydroscoop - Bulletin d'information MHyLab laboratoire de petite hydraulique

    Denis, V.


    This is issue Nr. 5 of the news bulletin of MHyLab, the small-scale hydraulic laboratory in Montcherand, Switzerland. The history of MHyLab development is recalled. The objective of the laboratory is given: the laboratory development of efficient and reliable turbines for the entire small-scale hydraulic range (power: 10 to 2000 kW, flow rate: 0.01 to 10 m{sup 3}/s, hydraulic head: 1 m up to more than 700 m). The first period (1997-2001) was devoted to Pelton turbines for high heads (60 to 70 m) and the second (2001-2009) to Kaplan turbines for low and very low heads (1 to 30 m). In the third period (beginning 2008) diagonal turbines for medium heads (25 to 100 m) are being developed. MHyLab designed, modelled and tested all these different types. The small-scale hydraulic market developed unexpectedly quickly. The potential of small-scale hydraulics in the Canton of Vaud, western Switzerland is presented. Three implemented projects are reported on as examples for MHyLab activities on the market place. The MHyLab staff is presented.

  6. Design of Pumps for Water Hydraulic Systems

    Klit, Peder; Olsen, Stefan; Bech, Thomas Nørgaard


    This paper considers the development of two pumps for water hydraulic applications. The pumps are based on two different working principles: The Vane-type pump and the Gear-type pump. Emphasis is put on the considerations that should be made to account for water as the hydraulic fluid.......KEYWORDS: water, pump, design, vane, gear....

  7. Hydraulic fracturing with distinct element method

    Pruiksma, J.P.; Bezuijen, A.


    In this report, hydraulic fracturing is investigated using the distinct element code PFC2D from Itasca. Special routines were written to be able to model hydraulic fracturing. These include adding fluid flow to PFC2D and updating the fluid flow domains when fractures appear. A brief description of t

  8. Hydraulic Actuator for Ganged Control Rods

    Thompson, D. C.; Robey, R. M.


    Hydraulic actuator moves several nuclear-reactor control rods in unison. Electromagnetic pump pushes liquid lithium against ends of control rods, forcing them out of or into nuclear reactor. Color arrows show lithium flow for reactor startup and operation. Flow reversed for shutdown. Conceived for use aboard spacecraft, actuator principle applied to terrestrial hydraulic machinery involving motion of ganged rods.

  9. Control arrangement for the actuation of hydraulic consumers

    Kussel, W.; Dettmers, M.; Weirich, W.


    An arrangement for controlling the actuation of hydraulic consumers, by selectively connecting the consumers to hydraulic pressure and return lines; the control arrangement comprising a respective hydraulically operated directional control valve associated with each of the hydraulic consumers, a respective electro-magnetically operated pre-control valve associated with each of the hydraulic directional control valves, and further electro-magnetically operated directional control valve means associated with the pre-control valves, each of the hydraulic consumers being connectible to the hydraulic pressure or return lines via the associated hydraulically operated directional control valve which is actuatable by a hydraulic control line leading from the output of the associated pre-control valve, wherein the inputs of the pre-control valves are connected directly to the hydraulic return line and indirectly, via the further control valve means, to the hydraulic return line or to a hydraulic control pressure line.

  10. Scaling hydraulic properties of a macroporous soil

    Mohanty, Binayak P.


    Macroporous soils exhibit significant differences in their hydraulic properties for different pore domains. Multimodal hydraulic functions may be used to describe the characteristics of multiporosity media. I investigated the usefulness of scaling to describe the spatial variability of hydraulic conductivity (K(-h)) functions of a macroporous soil in Las Nutrias, New Mexico. Piecewise-continuous hydraulic conductivity functions suitable for macroporous soils in conjunction with a hybrid similar media-functional normalization scaling approach were used. Results showed that gravity-dominated flow and the related hydraulic conductivity (K(minus;h) functions of the macropore region are more readily scalable than capillary-dominated flow properties of the mesopore and micropore regions. A possible reason for this behavior is that gravity-dominated flow in the larger pores is mostly influenced by the pore diameter which remains more uniform as compared to tortuous mesopores and micropores with variable neck and body sizes along the pore length.

  11. Hydraulic conductivity of GCLs in MSW landfills

    LI Guo-cheng; YANG Wu-chao; DAN Tang-hui


    The state of the art of the study on the hydraulic conductivity of GCLs is presented in terms of the in-fluence of the effective stress, chemical interactions, freeze - thaw cycles and temperature gradients. The chan-ges of void ratio caused by changes of effective stress have a direct linear effect on the hydraulic conductivity, regardless of the cation concentration or the thickness of the adsorbed layer. The hydraulic conductivity is relat-ed to the relative abundance of monovalent and divalent cation(RMD), and RMD has a great effect on the hy-draulic conductivity in weak solution. The long-term susceptibility of GCLs to increased hydraulic conductivity as a response to repeated freeze-thaw cycling is minimal, which has been proved after 150 freeze-thaw cycles. The potential of desiccation cracking increases with the increasing temperature gradient and is related to the ini-tial subsoil water content, the applied overburden stress, etc.

  12. Modeling and Simulation of Hydraulic Engine Mounts

    DUAN Shanzhong; Marshall McNea


    Hydraulic engine mounts are widely used in automotive powertrains for vibration isolation.A lumped mechanical parameter model is a traditional approach to model and simulate such mounts.This paper presents a dynamical model of a passive hydraulic engine mount with a double-chamber,an inertia track,a decoupler,and a plunger.The model is developed based on analogy between electrical systems and mechanical-hydraulic systems.The model is established to capture both low and high frequency dynatmic behaviors of the hydraulic mount.The model will be further used to find the approximate pulse responses of the mounts in terms of the force transmission and top chamber pressure.The close form solution from the simplifiod linear model may provide some insight into the highly nonlinear behavior of the mounts.Based on the model,computer simulation has been carried out to study dynamic performance of the hydraulic mount.

  13. Hydraulic test for evaluation of hydrophone VSP

    Yabuuchi, Satoshi; Koide, Kaoru [Power Reactor and Nuclear Fuel Development Corp., Toki, Gifu (Japan). Tono Geoscience Center


    This hydraulic test was carried out at the test site of Tono Geoscience Center, Mizunami-shi, Gifu Pref. in order to evaluate the reliability of the hydraulic conductivity estimated from hydrophone VSP experiment. From March to April 1997, we carried out measurements of pore-water pressure at five depths and permeability tests at seven depths down to G.L.-300m, within a borehole drilled in granitic rock. We compared the results of hydraulic test with hydrophone VSP experiment on condition that a single open fracture existed, and we obtained two notable results. First, for the granitic rock at which a single open fracture was found by BTV and also detected by hydrophone VSP experiment, the hydraulic conductivity was 1.54 x 10{sup -7} cm/sec, while for the same granitic rock at which another single open fracture was found by BTV but not detected by hydrophone VSP experiment, the hydraulic conductivity was less than 6 x 10{sup -10} cm/sec. Second, we converted the hydraulic conductivity of 1.54 x 10{sup -7} cm/sec which was obtained in a hydraulic test section of length 2.5 m into an equivalent value for a single open fracture of width 1 mm. The converted value (3.8 x 10{sup -4} cm/sec) was similar to the hydraulic conductivity estimated from hydrophone VSP experiment. In conclusion, the hydraulic test result shows that hydrophone VSP is useful to estimate an approximate hydraulic conductivity of a single open fracture. (author)

  14. Reduction of saltwater intrusion by modifying hydraulic conductivity

    Strack, O. D. L.; Stoeckl, L.; Damm, K.; Houben, G.; Ausk, B. K.; de Lange, W. J.


    We present an approach for reducing saltwater intrusion in coastal aquifers by artificially reducing the hydraulic conductivity in the upper part of selected areas by using a precipitate. We apply a previously presented analytical approach to develop formulas useful for the design of artificial barriers. Equations for the location of the tip of the saltwater wedge are presented and verified through a sand-tank experiment. The analysis is capable of computing discharges exactly, but requires the Dupuit-Forchheimer approximation to compute points of the interface between flowing fresh and stationary saltwater. We consider a vertical coastline and boundaries in the freshwater zone of either given discharge or given head. We demonstrate in the paper that reduction of the hydraulic conductivity in the upper part of a coastal aquifer will result in a decrease of saltwater intrusion, and present analytic expressions that can be used for design purposes. The previously presented analytical approach can be applied to design systems to reduce saltwater intrusion caused by pumping inland from the zone that contains saline groundwater.

  15. Thermal-hydraulic modeling needs for passive reactors

    Kelly, J.M. [Nuclear Regulatory Commission, Washington, DC (United States)


    The U.S. Nuclear Regulatory Commission has received an application for design certification from the Westinghouse Electric Corporation for an Advanced Light Water Reactor design known as the AP600. As part of the design certification process, the USNRC uses its thermal-hydraulic system analysis codes to independently audit the vendor calculations. The focus of this effort has been the small break LOCA transients that rely upon the passive safety features of the design to depressurize the primary system sufficiently so that gravity driven injection can provide a stable source for long term cooling. Of course, large break LOCAs have also been considered, but as the involved phenomena do not appear to be appreciably different from those of current plants, they were not discussed in this paper. Although the SBLOCA scenario does not appear to threaten core coolability - indeed, heatup is not even expected to occur - there have been concerns as to the performance of the passive safety systems. For example, the passive systems drive flows with small heads, consequently requiring more precision in the analysis compared to active systems methods for passive plants as compared to current plants with active systems. For the analysis of SBLOCAs and operating transients, the USNRC uses the RELAP5 thermal-hydraulic system analysis code. To assure the applicability of RELAP5 to the analysis of these transients for the AP600 design, a four year long program of code development and assessment has been undertaken.

  16. DLC coatings for hydraulic applications



    Replacement of lubricating oils with water or low-viscosity fluids is highly desirable in many industrial fields, on account of the environmental and economical advantages. Low lubricity of water might be insufficient for proper operation of hydraulic components, and diamond-like carbon(DLC) coatings are very attractive as solid lubricant films. A remote-plasma PACVD process was utilized to deposit hydrogenated DLC coatings (a-C:H) on different substrates. Microindentation measurements show that the coating hardness is around 35 GPa. Tribological behavior was evaluated by block-on-ring tests performed in water and water with alumina. The wear rate was calculated after measuring the wear volume by a laser profilemeter. Morphological and compositional analysis of the wear tracks reveal that coating failure may occur by abrasive wear or delamination, depending on the substrate properties. Hard and smooth substrates give the best results and dispersed alumina particles increase the wear rate.

  17. Aircraft Hydraulic Systems Dynamic Analysis


    4400 PSIG OUTLET PRESSURE ~’f UM5 S1 l .( FIF ~0RV lR 1 .I. AP (c R (V) IFWM) APPROX C ASE !VPý :iI S ReUN N•;MRF.. r p kN i t, isI A! f IN, I:E • ’l...and 1F.GI pump modelo were assumed from data supplied by CECO. 165 _ -- --- - SECTION V HYDRAULIC MOTOR MODEL DEVELOPMENT AND VERIFICATION A fixed...3 70 P.,0 601 ~4 M24.0 3 1p ’, 4 r I 1 1 ISIS 2411 APPENDIX E (CONT.) HSFR TECHNICAL MANUAL (AFAPL-TR-76-43, VOL. IV) 4.15 VANE PU`MP SUBROUTINE 4.15A

  18. Permeability Enhancement in Enhanced Geothermal System as a result of Hydraulic Fracturing and Jacking

    Jalali, Mohammadreza; Klepikova, Maria; Fisch, Hansruedi; Amann, Florian; Loew, Simon


    -coring tests, these data were used to conclude on the local stress orientation and stress magnitudes. The hydraulic response of the rock mass under hydro-mechanical perturbations was investigated by conducting various hydraulic packer tests (e.g. pulse, constant rate and constant head) in multiple hydraulically isolated borehole sections before and after the stress measurements. Hydraulic testing of borehole sections which were previously fracked (during HF tests) didn't show a distinct increase in permeability. For the tested borehole sections without natural fractures, this can be explained by the fact that hydraulic fracturing was dominated by fracture normal opening (mode I). In this case, the implemented pressure range (less than 2 MPa) during the hydraulic packer tests was not sufficient to re-open the tensile fractures and permeability would remain unchanged. Conversely, in borehole sections with pre-existing ductile and/or brittle fractures and where HTPF-tests were conducted, the permeability increased by two orders of magnitude, from 10-11 m2/s to˜10-9 m2/s (results of hydraulic tests pre and post HTPF). These findings could be explained by permanent enhancement of permeability as a result of shear dilation of existing structures. Considering the efficiency of the hydraulic stimulation process observed at low differential injection pressures, even more significant permeability enhancement is expected during the upcoming stimulation experiments.

  19. Head and Neck

    Højgaard, Liselotte; Berthelsen, Anne Kiil; Loft, Annika


    Positron emission tomography (PET)/computed tomography with FDG of the head and neck region is mainly used for the diagnosis of head and neck cancer, for staging, treatment evaluation, relapse, and planning of surgery and radio therapy. This article is a practical guide of imaging techniques......, including a detailed protocol for FDG PET in head and neck imaging, physiologic findings, and pitfalls in selected case stories....

  20. Hydraulic fracture propagation modeling and data-based fracture identification

    Zhou, Jing

    Successful shale gas and tight oil production is enabled by the engineering innovation of horizontal drilling and hydraulic fracturing. Hydraulically induced fractures will most likely deviate from the bi-wing planar pattern and generate complex fracture networks due to mechanical interactions and reservoir heterogeneity, both of which render the conventional fracture simulators insufficient to characterize the fractured reservoir. Moreover, in reservoirs with ultra-low permeability, the natural fractures are widely distributed, which will result in hydraulic fractures branching and merging at the interface and consequently lead to the creation of more complex fracture networks. Thus, developing a reliable hydraulic fracturing simulator, including both mechanical interaction and fluid flow, is critical in maximizing hydrocarbon recovery and optimizing fracture/well design and completion strategy in multistage horizontal wells. A novel fully coupled reservoir flow and geomechanics model based on the dual-lattice system is developed to simulate multiple nonplanar fractures' propagation in both homogeneous and heterogeneous reservoirs with or without pre-existing natural fractures. Initiation, growth, and coalescence of the microcracks will lead to the generation of macroscopic fractures, which is explicitly mimicked by failure and removal of bonds between particles from the discrete element network. This physics-based modeling approach leads to realistic fracture patterns without using the empirical rock failure and fracture propagation criteria required in conventional continuum methods. Based on this model, a sensitivity study is performed to investigate the effects of perforation spacing, in-situ stress anisotropy, rock properties (Young's modulus, Poisson's ratio, and compressive strength), fluid properties, and natural fracture properties on hydraulic fracture propagation. In addition, since reservoirs are buried thousands of feet below the surface, the

  1. The Early Outcomes with Titanium Radial Head Implants in the Treatment of Radial Head Comminuted Fractures

    ZHAO Jijun; YANG Shuhua; HU Yong


    The study assessed the early functional outcomes with cemented titanium implants of ra- dius in the treatment of comminuted fractures of radial heads. The functional outcomes of arthro- plasty with cemented titanium implants of radius in the treatment of radial head fractures (Mason Type Ⅲ: 6; Mason Type Ⅳ: 4) in l0 consecutive patients (mean age, 38 years) were evaluated over a mean time of 23.7 months (18-31 months). The patients were assessed on the basis of physical ex- amination, functional rating (Mayo) and radiographic findings. The parameters evaluated included motion, stability, pain, and grip strength. Five patients were considered to have excellent results, 4 patients had good results and 1 patient had fairly good results. There were no cases of infection, prosthetic failure, heterotopic ossification or dislocation. When medial collateral ligament was injured, radial head became the main stabilizing structure of the elbow. Titanium radial head implant may provide the stability similar to that of native radial head. We believe that titanium radial head im- plants may be indicated for the Mason Type Ⅲ and Mason Type Ⅳ radial head fractures.

  2. Examinations of factors influencing toe grip strength.

    Soma, Masayuki; Murata, Shin; Kai, Yoshihiro; Nakae, Hideyuki; Satou, Yousuke; Murata, Jun; Miyazaki, Junya


    [Purpose] This study examined the relationship between toe grip strength and its associated factors by focusing on factors that were suggested to have a relationship with toe grip strength in previous studies, aiming to clarify the factors influencing the toe grip strength of healthy women. [Subjects and Methods] Twelve healthy young women were selected for this study. Their toe grip strength, angular changes in their ankle joint during toe grip, maximum voluntary contraction activities of the rectus femoris, biceps femoris, and tibialis anterior muscles, and the medial head of the gastrocnemius muscles were measured using electromyography. Their toe curl ability, foot-arch height ratio, and weight were also measured. [Results] Multiple regression analysis demonstrated that the predictors of toe grip strength in the resulting model were foot-arch height ratio and the percentage of integrated electromyography (%IEMG) of the tibialis anterior muscle, as the dependent variables. This reveals that women whose tibialis anterior muscle %IEMG values and foot-arch height ratio are high have greater %IEMG values have greater toe grip strength. [Conclusion] These findings suggest a significant relationship between foot-arch height ratio and toe grip strength, with a reciprocal interaction. These findings further indicate that the risk of falls by the elderly could be decreased if toe grip strength were enhanced, by increasing the height of a low foot-arch with the help of an inserted insole.

  3. Development and implementation of a fluid flow code to evaluate block hydraulic behaviors of the fractured rock masses

    Um, Jeong-Gi; Han, Jisu; Lee, Dahye; Cho, Taechin


    A computer program code was developed to estimate the hydraulic head distribution through the 2-D DFN(discrete fracture network) blocks considering hydraulic aperture of the individual fractures, and to determine flow quantity, directional block hydraulic conductivity and principal hydraulic conductivity tensor according to fracture geometry such as orientation, frequency and size of the fracture network systems. The generated stochastic DFN system is assumed to have a network structure in which the equivalent flow pipe composed linear fractures is complexly connected. DFN systems often include individual or group of sub-network that are isolated from a network that can act as fluid flow passages from one flow boundary to another, and the fluid flow is completely blocked due to lack of connectivity. Fractures that are completely or partially isolated in the DFN system do not contribute to the overall fluid flow through the DFN system and add to the burden of numerical computation. This sometimes leads to numerical instability and failure to provide a solution. In this study, geometric and mathematical routines were designed and implemented to classify and eliminate such sub-networks. The developed program code can calculate the total head at each node connected to the flow path with various aperture as well as hydraulic conductivity of the individual flow pipe using the SOR method. Numerical experiments have been carried out to explore the applicability of the developed program code. A total of 108 stochastic 2-D DFN blocks of 20 m×20 m with various hydraulic aperture were prepared using two joint sets with fixed input parameters of fracture orientation, frequency and size distribution. The hydraulic anisotropy and the chance for equivalent continuum behavior of the DFN system were found to depend on the variability of fracture aperture.

  4. Analyzing the effects of geological and parameter uncertainty on prediction of groundwater head and travel time

    He, X.; Sonneborg, T.O.; Jørgensen, F.


    in three scenarios involving simulation of groundwater head distribution and travel time. The first scenario implied 100 stochastic geological models all assigning the same hydraulic parameters for the same geological units. In the second scenario the same 100 geological models were subjected to model...

  5. Design optimization of harvester head and actuation system of forest harvester

    Andersen, Torben Ole; Hansen, Michael R.; Mouritsen, Ole Ø.


    This paper is on the analysis and subsequent efficiency optimization of a forrest harvester. As basis for the optimization the existing machine has undergone substantial experimental testing with a view to determine the loading that the harvester head is subjected to and also the corresponding ef...... efficiency of the hydraulic actuation system during a typical working cycle....

  6. Technical and Economical Evaluations of Canola Harvesting Losses in Different Maturity Stages Using Three Different Combine Harverster Heads

    J Taghinazhad


    Full Text Available Rapeseed cultivation in Iran is growing rapidly while this product has been facing specific problems. Every year a significant portion of edible oil is imported to the country from other countries. Despite this deficit, a great amount of canola is being lost every year. Therefore, in compliance with technical points, adding a suitable platform to the exisiting machineries may reduce the losses. A field study was conducted in Moghan Agricultural Research Centre to study the technical and economical characteristics of harvesting machineries and evaluate Canola harvesting losses in different maturity stages, using three different combine harvester heads. The experiments were conducted in a completely randomized\tsplit split plot design with four replications. The main plot included seed maturity stage at three levels: A 60%, B 70% and C 80%, and the subplot was the harvester’s ground speed at three levels: A 1.5, B 2.5 and C 3.5 km h-1. The sub-subplot was combine head type with three forms: A Mechanical, B Hydraulically Joybar and C Hydraulically Biso's Head. The results of ANOVA showed that maximum cutter bar losses occurred with Mechanical Head (5.36% while the loss of Hydraulically Joybar's and Biso's head were 4.28 and 4.13 %, respectively. The results also showed that the maximum cutter bar losses occurred when 80% of seeds were matured and adequate time for canola harvesting was 70% of seeds maturity. The results of analysing the effects of harvesting ground speeds showed that the maximum cutter bar losses occurred with the speed of 3.5 km h-1. Finally, the results showed that the minimum cutter bar loss was obtained with Hydraulically Joybar's head considering the benefit per cost ratio. The cost for Mechanical head and Hydraulically Biso's head were 13500 and 262500 Rial ha-1, respectively.

  7. Very Low Head Turbine Deployment in Canada

    Kemp, P.; Williams, C.; Sasseville, Remi; Anderson, N.


    The Very Low Head (VLH) turbine is a recent turbine technology developed in Europe for low head sites in the 1.4 - 4.2 m range. The VLH turbine is primarily targeted for installation at existing hydraulic structures to provide a low impact, low cost, yet highly efficient solution. Over 35 VLH turbines have been successfully installed in Europe and the first VLH deployment for North America is underway at Wasdell Falls in Ontario, Canada. Deployment opportunities abound in Canada with an estimated 80,000 existing structures within North America for possible low-head hydro development. There are several new considerations and challenges for the deployment of the VLH turbine technology in Canada in adapting to the hydraulic, environmental, electrical and social requirements. Several studies were completed to determine suitable approaches and design modifications to mitigate risk and confirm turbine performance. Diverse types of existing weirs and spillways pose certain hydraulic design challenges. Physical and numerical modelling of the VLH deployment alternatives provided for performance optimization. For this application, studies characterizing the influence of upstream obstacles using water tunnel model testing as well as full-scale prototype flow dynamics testing were completed. A Cold Climate Adaptation Package (CCA) was developed to allow year-round turbine operation in ice covered rivers. The CCA package facilitates turbine extraction and accommodates ice forces, frazil ice, ad-freezing and cold temperatures that are not present at the European sites. The Permanent Magnet Generator (PMG) presents some unique challenges in meeting Canadian utility interconnection requirements. Specific attention to the frequency driver control and protection requirements resulted in a driver design with greater over-voltage capability for the PMG as well as other key attributes. Environmental studies in Europe included fish friendliness testing comprised of multiple in

  8. Effects of volute geometry and impeller orbit on the hydraulic performance of a centrifugal pump

    Flack, R. D.; Lanes, R. F.


    Overall performance data was taken for a Plexiglas water pump with a logarithmic spiral volute and rectangular cross sectioned flow channels. Parametric studies were made in which the center of the impeller was offset from the design center of the volute. The rig was also designed such that the impeller was allowed to synchronously orbit by a fixed amount about any center. The studies indicate that decreasing the tongue clearance decreases the head at low flowrates and increases the head at high flowrates. Also, decreasing the volute area in the first half of the volute and holding the tongue clearance the same, resulted in a decreased head for low flowrates but performance at high flowrates was not affected. Finally, the overall hydraulic performance was not affected by the impeller orbitting about the volute center.

  9. Hydraulic Monitoring of Low-Permeability Argillite at the Meuse/Haute Marne Underground Research Laboratory

    Delay, Jacques; Cruchaudet, Martin

    ANDRA (Agence Nationale pour la Gestion de Déchets Radioactifs) has developed an electromagnetic permanent gauge (EPG) for long term monitoring of pore pressures in low permeability Callovo-Oxfordian argillites. The EPG is a pressure gauge that is permanently cemented into a borehole with no wire or tubing connections. The EPG transmits its data electromagnetically through the rock. Improvements in batteries have extended the life of the EPG to six years or more. Data from EPG installations in two holes near ANDRAs underground laboratory provide information on hydraulic conductivity and head. The heads in the argillites of the laboratory site are higher than heads in the two encasing carbonate units. These anomalous overpressures provide evidence for the very low permeability of the rock. Possible mechanisms for the overpressure include osmotic flows due to chemical potential gradients or delayed responses to the evolution of the regional groundwater hydrodynamics.


    Santos De La Cruz, Eulogio; Universidad Nacional Mayor de San Marcos; Rojas Lazo, Oswaldo; Universidad Nacional Mayor de San Marcos; Yenque Dedios, Julio; Universidad Nacional Mayor de San Marcos; Lavado Soto, Aurelio; Universidad Nacional Mayor de San Marcos


    A hydraulic system project includes the design, materials selection and construction of the hydraulic piston, hydraulic circuit and the joint with the pump and its accesories. This equiment will be driven by the force of moving fluid, whose application is in the devices of machines, tools, printing, perforation, packing and others. El proyecto de un sistema hidráulico, comprende el diseño, selección de materiales y construcción del pistón hidráulico, circuito hidráulico y el ensamble con l...

  11. Bubble visualization in a simulated hydraulic jump

    Witt, Adam; Shen, Lian


    This is a fluid dynamics video of two- and three-dimensional computational fluid dynamics simulations carried out at St. Anthony Falls Laboratory. A transient hydraulic jump is simulated using OpenFOAM, an open source numerical solver. A Volume of Fluid numerical method is employed with a realizable k-epsilon turbulence model. The goal of this research is to model the void fraction and bubble size in a transient hydraulic jump. This fluid dynamics video depicts the air entrainment characteristics and bubble behavior within a hydraulic jump of Froude number 4.82.

  12. Head Injuries in Children

    Pennington, Nicole


    School nurses play a crucial role in injury prevention and initial treatment when injuries occur at school. The role of school nurses includes being knowledgeable about the management of head injuries, including assessment and initial treatment. The school nurse must be familiar with the outcomes of a head injury and know when further evaluation…

  13. Hydraulic Fracturing and the Environment

    Ayatollahy Tafti, T.; Aminzadeh, F.; Jafarpour, B.; de Barros, F.


    In this presentation, we highlight two key environmental concerns of hydraulic fracturing (HF), namely induced seismicity and groundwater contamination (GC). We examine the induced seismicity (IS) associated with different subsurface fluid injection and production (SFIP) operations and the key operational parameters of SFIP impacting it. In addition we review the key potential sources for possible water contamination. Both in the case of IS and GC we propose modeling and data analysis methods to quantify the risk factors to be used for monitoring and risk reduction. SFIP include presents a risk in hydraulic fracturing, waste water injection, enhanced oil recovery as well as geothermal energy operations. Although a recent report (NRC 2012) documents that HF is not responsible for most of the induced seismicities, we primarily focus on HF here. We look into vaious operational parameters such as volume and rate of water injection, the direction of the well versus the natural fracture network, the depth of the target and the local stress field and fault system, as well as other geological features. The latter would determine the potential for triggering tectonic related events by small induced seismicity events. We provide the building blocks for IS risk assessment and monitoring. The system we propose will involve adequate layers of complexity based on mapped seismic attributes as well as results from ANN and probabilistic predictive modeling workflows. This leads to a set of guidelines which further defines 'safe operating conditions' and 'safe operating zones' which will be a valuable reference for future SFIP operations. We also illustrate how HF can lead to groundwater aquifer contamination. The source of aquifer contamination can be the hydrocarbon gas or the chemicals used in the injected liquid in the formation. We explore possible pathways of contamination within and discuss the likelihood of contamination from each source. Many of the chemical compounds used

  14. Ultra-low-head hydroelectric technology: A review

    Zhou, Daqing; Deng, Zhiqun (Daniel)


    In recent years, distributed renewable energy-generation technologies, such as wind and solar, have developed rapidly. Nevertheless, the utilization of ultra-low-head (ULH) water energy (i.e., situations where the hydraulic head is less than 3 m or the water flow is more than 0.5 m/s with zero head) has received little attention. We believe that, through technological innovations and cost reductions, ULH hydropower has the potential to become an attractive, renewable, and sustainable resource. This paper investigates potential sites for ULH energy resources, the selection of relevant turbines and generators, simplification of civil works, and project costs. This review introduces the current achievements on ULH hydroelectric technology to stimulate discussions and participation of stakeholders to develop related technologies for further expanding its utilization as an important form of renewable energy.

  15. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    Kim, Hyo-gon; Han, Changsoo [Hanyang University, Seoul (Korea, Republic of); Lee, Jong-won [Korea University of Science and Technology, Seoul (Korea, Republic of); Park, Sangdeok [Korea Institute of Industrial Technology, Seoul (Korea, Republic of)


    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program.

  16. Evaluation of actual and estimated hydraulic conductivity of sands with different gradation and shape.

    Cabalar, Ali Firat; Akbulut, Nurullah


    Hydraulic conductivities of sands with different gradation and grain shape were estimated experimentally at a relative density (Dr) of about 40 % and a 22 ± 2 °C of constant temperature. Narli Sand (NS) with 0.67 of sphericity (S) and 0.72 of roundness (R), and Crushed Stone Sand (CSS) with 0.55 of S and 0.15 of R values were artificially graded into sixteen different grain-size fractions (4.75-2, 2-1.18, 1.18-0.6, 0.6-0.425, 0.425-0.3, 0.3-0.075, 4.75-0.075, 2-0.075, 1.18-0.075, 0.6-0.075, 0.425-0.075, 4.75-0.6, 2-0.6, 4.75-0.425, 2-0.425, 1.18-0.425 mm). Hydraulic conductivities of the NS estimated by use of constant head test ranged from 1.61 to 0.01 cm/s, whilst those of the CSS estimated by the same test ranged from 2.45 to 0.012 cm/s. It was observed that the hydraulic conductivity values of the NS are lower than those of the CSS samples, which is likely to be the result of differences in shape, particularly in R values. The results clearly demonstrated that the hydraulic conductivity can be significantly influenced by grading characteristics (d10, d20, d30, d50, d60, cu, cc, n, Io). Furthermore, comparisons between results obtained in the present study and hydraulic conductivity estimated with other formulas available in the literature were made. The comparisons indicated that the best estimation of hydraulic conductivity changes based on the gradation and shape properties of the sands tested.


    coldhardened by deforming to 83%. It was found that it has low static notch sensitivity (lower than that of heat-treated steels), that static strength raised appreciably by increased cold plastic deformation, and that its fatigue strength is raised substantially by mechanical polishing. (Author)

  18. Ulnar Head Replacement and Related Biomechanics

    Sauerbier, Michael; Arsalan-Werner, Annika; Enderle, Elena; Vetter, Miriam; Vonier, Daniel


    A stable distal radioulnar joint (DRUJ) is mandatory for the function and load transmission in the wrist and forearm. Resectional salvage procedures such as the Darrach procedure, Bowers arthroplasty, and Sauvé-Kapandji procedure include the potential risk of radioulnar instability and impingement, which can lead to pain and weakness. Soft tissue stabilizing techniques have only limited success rates in solving these problems. In an attempt to stabilize the distal forearm mechanically following ulnar head resection, various endoprostheses have been developed to replace the ulnar head. The prostheses can be used for secondary treatment of failed ulnar head resection, but they can also achieve good results in the primary treatment of osteoarthritis of the DRUJ. Our experience consists of twenty-five patients (follow-up 30 months) with DRUJ osteoarthritis who were treated with an ulnar head prosthesis, with improvement in pain, range of motion, and grip strength. An ulnar head prosthesis should be considered as a treatment option for a painful DRUJ. PMID:24436786

  19. Parker Hybrid Hydraulic Drivetrain Demonstration

    Collett, Raymond [Parker-Hannifin Corporation, Cleveland, OH (United States); Howland, James [Parker-Hannifin Corporation, Cleveland, OH (United States); Venkiteswaran, Prasad [National Energy Technology Lab. (NETL), Morgantown, WV (United States)


    This report examines the benefits of Parker Hannifin hydraulic hybrid brake energy recovery systems used in commercial applications for vocational purposes. A detailed background on the problem statement being addressed as well as the solution set specific for parcel delivery will be provided. Objectives of the demonstration performed in high start & stop applications included opportunities in fuel usage reduction, emissions reduction, vehicle productivity, and vehicle maintenance. Completed findings during the demonstration period and parallel investigations with NREL, CALSTART, along with a literature review will be provided herein on this research area. Lastly, results identified in the study by third parties validated the savings potential in fuel reduction of on average of 19% to 52% over the baseline in terms of mpg (Lammert, 2014, p11), Parker data for parcel delivery vehicles in the field parallels this at a range of 35% - 50%, emissions reduction of 17.4% lower CO2 per mile and 30.4% lower NOx per mile (Gallo, 2014, p15), with maintenance improvement in the areas of brake and starter replacement, while leaving room for further study in the area of productivity in terms of specific metrics that can be applied and studied.

  20. Thermal hydraulics development for CASL

    Lowrie, Robert B [Los Alamos National Laboratory


    This talk will describe the technical direction of the Thermal-Hydraulics (T-H) Project within the Consortium for Advanced Simulation of Light Water Reactors (CASL) Department of Energy Innovation Hub. CASL is focused on developing a 'virtual reactor', that will simulate the physical processes that occur within a light-water reactor. These simulations will address several challenge problems, defined by laboratory, university, and industrial partners that make up CASL. CASL's T-H efforts are encompassed in two sub-projects: (1) Computational Fluid Dynamics (CFD), (2) Interface Treatment Methods (ITM). The CFD subproject will develop non-proprietary, scalable, verified and validated macroscale CFD simulation tools. These tools typically require closures for their turbulence and boiling models, which will be provided by the ITM sub-project, via experiments and microscale (such as DNS) simulation results. The near-term milestones and longer term plans of these two sub-projects will be discussed.

  1. Transputer Control of Hydraulic Actuators and Robots

    Conrad, Finn


    Results from a Danish mechatronics research program entitled IMCIA - Intelligent Control and Intelligent Actuators. The objective is development of intelligent actuators for intelligent motion control. A mechatronics test facility with a transputer controlled hydraulic robot suiteable for real...

  2. Concept Evaluation for Hydraulic Yaw System

    Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole


    a suspension system on a car, leading the loads away from the turbine structure. However, to realize a soft hydraulic yaw system a new design concept must be found. As a part of the development of the new concept a preliminary concept evaluation has been conducted, evaluating seven different hydraulic yaw...... concepts, ranging from a one-to-one copy of the electrical drive (electrical drives replaced by hydraulic dittos), to floating suspension systems mounted on hydraulic cylinders. Rough calculations of size and consequences of the different systems are presented ending up with the final concept for further...... investigation. Loads and yaw demands are based on the IEC 61400-1 standard for wind turbine design, and the loads for this examination are extrapolated from the HAWC2 aeroelastic design code. The concepts are based on a 5 MW off-shore turbine....


    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...


    Vijay P. SINGH


    Hydraulic geometry is of fundamental importance in planning, design, and management of river engineering and training works. Although some concepts of hydraulic geometry were proposed toward the end of the nineteenth century, the real impetus toward formulating a theory of hydraulic geometry was provided by the work of Leopold and Maddock (1953). A number of theories have since been proposed.Some of the theories are interrelated but others are based on quite different principles. All theories,however, assume that the river flow is steady and uniform and the river tends to attain a state of equilibrium or quasi-equilibrium. The differences are due to the differences in hydraulic mechanisms that the theories employ to explain the attainment of equilibrium by the river.

  5. Stream restoration hydraulic design course: lecture notes

    Newbury, R


    Steam restoration encompasses a broad range of activities and disciplines. This lecture series is designed for practitioners who must fit habitat improvement works in the hydraulics of degraded channels...

  6. Drawing a pictogram operator - hydraulic stowing assembly

    Bukhgol' ts, V.P.; Dinershtein, V.A.


    Hydraulic stowing is widely used during the extraction of coal from seams prone to spontaneous ignition or from seams situated under preserved structures. Experience has shown that the presence of a considerable number of controlling and measuring devices on hydraulic stowing assemblies results in erratic operations. The authors, after examining the controls of the hydraulic stowing complexes, recommend that all functions which the operator might perform badly or not at all should be controlled automatically. The operator must, however, have access to manual controls which should be included in the system in order to achieve an effective and trouble free operation. The authors propose a pictogram to explain the relationship between the human operator and the hydraulic complex, based on structural diagrams. The system developed, which was tried out at the Koksovaya mine, increased the efficiency of the complex and reduced the work load of the operator. 3 references.


    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...

  8. Hydraulic fracturing chemicals and fluids technology

    Fink, Johannes


    When classifying fracturing fluids and their additives, it is important that production, operation, and completion engineers understand which chemical should be utilized in different well environments. A user's guide to the many chemicals and chemical additives used in hydraulic fracturing operations, Hydraulic Fracturing Chemicals and Fluids Technology provides an easy-to-use manual to create fluid formulations that will meet project-specific needs while protecting the environment and the life of the well. Fink creates a concise and comprehensive reference that enables the engineer to logically select and use the appropriate chemicals on any hydraulic fracturing job. The first book devoted entirely to hydraulic fracturing chemicals, Fink eliminates the guesswork so the engineer can select the best chemicals needed on the job while providing the best protection for the well, workers and environment. Pinpoints the specific compounds used in any given fracturing operation Provides a systematic approach to class...

  9. Transputer Control of Hydraulic Actuators and Robots

    Conrad, Finn


    Results from a Danish mechatronics research program entitled IMCIA - Intelligent Control and Intelligent Actuators. The objective is development of intelligent actuators for intelligent motion control. A mechatronics test facility with a transputer controlled hydraulic robot suiteable for real...

  10. Is inversion based high resolution characterization of spatially heterogeneous river bed hydraulic conductivity needed and possible?

    W. Kurtz


    Full Text Available River-aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river-aquifer exchange fluxes tend to be strongly spatially variable and it is an open research question to which degree river bed heterogeneity has to be represented in a~model in order to achieve reliable estimates of river-aquifer exchange fluxes. This research question is addressed in this paper with help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river-aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated-saturated subsurface hydrological flow problem including river-aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with help of the Ensemble Kalman Filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high resolution L-fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher resolution L-fields (i.e., fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream-aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high resolution L-fields outperform the

  11. 46 CFR 112.50-3 - Hydraulic starting.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Hydraulic starting. 112.50-3 Section 112.50-3 Shipping... POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets § 112.50-3 Hydraulic starting. A hydraulic starting system must meet the following: (a) The hydraulic starting system must be...

  12. 21 CFR 870.2780 - Hydraulic, pneumatic, or photoelectric plethysmographs.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydraulic, pneumatic, or photoelectric... § 870.2780 Hydraulic, pneumatic, or photoelectric plethysmographs. (a) Identification. A hydraulic... using hydraulic, pneumatic, or photoelectric measurement techniques. (b) Classification. Class...



    The tensile strength of test liquid affects the cavitation inception numbers very seriously, and the zero-tensile strength as a criterion for detection of the cavitation inception numbers can be used, in order to reduce the influence of tensile strength. The scale effect on measuring zero-tensile strength of test liquid based on hydraulic methods must be considered. it is supposed that the zero-tensile strength can be defined by use of the comparative method, which unites the classical theory of cavitation inception with the modern one based on an identical criterion.


    Zhao Jingyi; Zhuoru; Wang Yiqun


    According to the demand of high reliability of the primary cylinder of the hydraulic press,the reliability model of the primary cylinder is built after its reliability analysis.The stress of the primary cylinder is analyzed by finite element software-MARC,and the structure reliability of the cylinder based on stress-strength model is predicted,which would provide the reference to the design.

  15. Introduction of Explosive Cladding Technology for the Manufacturing of Hydraulic Cylinders

    Jovišević, V.


    Full Text Available The microhardness, microstructure and bond strength of the interface of a bi-metallic joint on the cross-section of the testing hydraulic cylinder were investigated. Experimental findings of related to both method of cladding obtained with metallographic and mechanical investigations of the interface between the CuSn6 bronze and the TS5 (Č.1213 steel cylinder, are given.

  16. Determination of hydraulic conductivities of low permeability materials in the Sierra Ladrones Formation, Albuquerque basin

    Planert, C.S.


    Low permeability materials in the Sierra Ladrones Formation were sampled and analyzed to determine their hydraulic conductivities using the falling head centrifugation method (fc) as described by Nimmo et al. (1991). The method is similar to the traditional falling head method, only it uses greatly increased centrifugal forces, allowing measurements to make in a relatively short amount of time. Using these measurements, variations in saturated hydraulic conductivities between different sediment types were analyzed using Analysis of Variance (ANOVA). Sampling resulted in useable data chiefly from the clay and silt facies of the formation. The range of conductivities determined are representative of brown and red clays, and silts which make up the overbank deposits of this region. Hydraulic conductivities for these overbank fines were found to range from approximately log K = {minus}9 m/s to log K = {minus}7 m/s. The upper measurement limit of the centrifuge apparatus was determined to be approximately 1.43 {times} 10{sup {minus}7} m/s and the lower limit was approximately 7.6 {times} 10{sup {minus}12} m/s.

  17. Influence of aquifer heterogeneity on karst hydraulics and catchment delineation employing distributive modeling approaches

    S. Oehlmann


    Full Text Available Due to their heterogeneous nature, karst aquifers pose a major challenge for hydrogeological investigations. Important procedures like the delineation of catchment areas for springs are hindered by the unknown locations and hydraulic properties of highly conductive karstic zones. In this work numerical modeling was employed as a tool in delineating catchment areas of several springs within a karst area in southwestern Germany. For this purpose, different distributive modeling approaches were implemented in the Finite Element simulation software Comsol Multiphysics®. The investigation focuses on the question to which degree the effect of karstification has to be taken into account for accurately simulating the hydraulic head distribution and the observed spring discharges. The results reveal that the representation of heterogeneities has a large influence on the delineation of the catchment areas. Not only the location of highly conductive elements but also their geometries play a major role for the resulting hydraulic head distribution and thus for catchment area delineation. The size distribution of the karst conduits derived from the numerical models agrees with knowledge from karst genesis. It was thus shown that numerical modeling is a useful tool for catchment delineation in karst aquifers based on results from different field observations.



    A new typed hydraulic system of electro-hydraulic hammer is researched and developed.By means of power bond graphs the modeling and simulation to the dynamic characteristics of the new hydraulic system are performed. The experimental research which is emphasized on the blowing stroke is also performed. It is proved from the result of simulation and experiment that this new hydraulic system possesses such advantages as simplification of structure,flexibleness of operation and reliability of working. Especially it possesses better dynamic characteristics.

  19. Design of a laboratory hydraulic device for testing of hydraulic pumps

    Pavel Máchal


    Full Text Available The present contribution deals with solves problem of research of testing device to monitor of hydrostatic pumps durability about dynamic loading under laboratory conditions. When carrying out the design of testing device are based on load characteristics of tractor hydraulic circuit, the individual characteristics of hydraulic components and performed calculations. Load characteristics on the tractors CASE IH Magnum 310, JOHN DEERE 8100, ZETOR FORTERRA 114 41 and Fendt 926 Vario were measured. Design of a hydraulic laboratory device is based on the need for testing new types of hydraulic pumps or various types of hydraulic fluids. When creating of hydraulic device we focused on testing hydraulic pumps used in agricultural and forestry tractors. Proportional pressure control valve is an active member of the hydraulic device, which provides change of a continuous control signal into relative pressure of operating fluid. The advantage of a designed hydraulic system is possibility of simulation of dynamic operating loading, which is obtained by measurement under real conditions, and thereby creates laboratory conditions as close to real conditions as possible. The laboratory device is constructed at the Department of Transport and Handling, Faculty of Engineering, Slovak University of Agriculture in Nitra.

  20. Characterisation of river-aquifer exchange fluxes: The role of spatial patterns of riverbed hydraulic conductivities

    Tang, Q.; Kurtz, W.; Brunner, P.; Vereecken, H.; Hendricks Franssen, H.-J.


    KF and NS-EnKF improve the characterisation of non-MultiGaussian riverbed properties, hydraulic heads and exchange fluxes by piezometric head assimilation, and only NS-EnKF could preserve the initial distribution of riverbed hydraulic conductivities.

  1. Characterization of a hydraulically induced bedrock fracture


    Hydraulic fracturing is a controversial practice because of concerns about environmental impacts due to its widespread use in recovering unconventional petroleum and natural gas deposits. However, water-only hydraulic fracturing has been used safely and successfully for many years to increase the permeability of aquifers used for drinking and irrigation water supply. This process extends and widens existing bedrock fractures, allowing groundwater storage to increase. Researchers have studied ...


    Andersen, Torben Ole; Hansen, Michael Rygaard; Pedersen, Henrik C.;


    Generally most hydraulic systems are intrensically non-linear, why applying linear control techniques typically results in conservatively dimensioned controllers to obtain stable performance. Non-linear control techniques have the potential of overcoming these problems, and in this paper the focus...... is on developing and applying several different feedback linearisation (FL) controllers to the individual servo actuators in a hydraulically driven servo robot to evaluate and compare their possiblities and limitations. This is done based on both simulation and experimental results....

  3. Data Analytics of Hydraulic Fracturing Data

    Zhang, Jovan Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Viswanathan, Hari [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffery [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Middleton, Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    These are a set of slides on the data analytics of hydraulic fracturing data. The conclusions from this research are the following: they proposed a permeability evolution as a new mechanism to explain hydraulic fracturing trends; they created a model to include this mechanism and it showed promising results; the paper from this research is ready for submission; they devised a way to identify and sort refractures in order to study their effects, and this paper is currently being written.

  4. Chemical Contamination Sensor for Phosphate Ester Hydraulic Fluids

    Sumit Paul


    Full Text Available The paper deals with chemical contamination monitoring in phosphate-ester-based hydraulic fluids using nondispersive infrared (NDIR optical absorption. Our results show that NDIR monitoring allows detecting the take-up of water into such fluids and their hydrolytic disintegration as these become additionally stressed by Joule heating. Observations on the O–H stretching vibration band (3200–3800 cm−1 are used for determining the free water content (0–1.5% and the Total Acid Number (0–1 mgKOH/g. Both quantities can be assessed by monitoring the strength and the asymmetry of the O–H vibration band with regard to the free water absorption band centred around 3500 cm−1. As such optical parameters can be assessed without taking fluid samples from a pressurised hydraulic system, fluid degradation trends can be established based on regular measurements, before irreversible damage to the fluid has occurred. Therefore maintenance actions can be planned accordingly, which is very important for the airline, as unscheduled maintenance disturbs the flights organisation and often generates money loss.

  5. Current status of the quantification of roughness and the peak shear strength criteria for rock joints

    Park, Byoung Yoon; Kang, Chul Hyung


    In order to understand the effects of spent nuclear fuel on the hydraulic behaviour of the rock mass it is necessary to have knowledge about the relationship between the stresses and hydraulic properties of the fractures. The roughness of a fracture surface govern the dilation of the fracture and the displacement of the fracture surface under shear stress. The peak shear strength and hydraulic flow properties of fractures depend very much on the surface roughness. This report describes different methods and techniques used in the characterization of rock joint surfaces and their applications in rock mechanics. Joint roughness is an important factor in the shear resistance of a joint. The joint shear strength shows anisotropic properties due to roughness variation with the shearing direction in direct shear tests. Various shear strength criteria are described in this report. (author)

  6. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the head is performed ...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the head is performed ...

  8. Hydraulic Motor Driving Variable-Pitch System for Wind Turbine

    Ye HUANG


    Full Text Available The present hydraulic variable-pitch mechanism of wind turbine uses three hydraulic cylinders to drive three crank and connecting rod mechanisms respectively; the blades are moved with the cranks. The hydraulic variable-pitch mechanism has complex structure, occupies a lot of space and its maintenance is trouble. In order to make up for the shortcomings of hydraulic cylinder variable-pitch system, the present hydraulic variable-pitch mechanism should be changed as follows: hydraulic motors are used to drive gears; gears drive blades; the electro-hydraulic proportional valves are used to control hydraulic motors. The hydraulic control part and electrical control part of variable-pitch system is redesigned. The new variable-pitch system is called hydraulic motor driving variable-pitch system. The new variable-pitch system meets the control requirements of blade pitch, makes the structure simple and its application effect is perfect.    

  9. Ulnar head replacement.

    Herbert, Timothy J; van Schoonhoven, Joerg


    Recent years have seen an increasing awareness of the anatomical and biomechanical significance of the distal radioulnar joint (DRUJ). With this has come a more critical approach to surgical management of DRUJ disorders and a realization that all forms of "excision arthroplasty" can only restore forearm rotation at the expense of forearm stability. This, in turn, has led to renewed interest in prosthetic replacement of the ulnar head, a procedure that had previously fallen into disrepute because of material failures with early implants, in particular, the Swanson silicone ulnar head replacement. In response to these early failures, a new prosthesis was developed in the early 1990s, using materials designed to withstand the loads across the DRUJ associated with normal functional use of the upper limb. Released onto the market in 1995 (Herbert ulnar head prosthesis), clinical experience during the last 10 years has shown that this prosthesis is able to restore forearm function after ulnar head excision and that the materials (ceramic head and noncemented titanium stem), even with normal use of the limb, are showing no signs of failure in the medium to long term. As experience with the use of an ulnar head prosthesis grows, so does its acceptance as a viable and attractive alternative to more traditional operations, such as the Darrach and Sauve-Kapandji procedures. This article discusses the current indications and contraindications for ulnar head replacement and details the surgical procedure, rehabilitation, and likely outcomes.

  10. Investigation of the fluid-structure interaction of a high head Francis turbine using OpenFOAM and Code_Aster

    Eichhorn, M.; Doujak, E.; Waldner, L.


    The increasing energy consumption and highly stressed power grids influence the operating conditions of turbines and pump turbines in the present situation. To provide or use energy as quick as possible, hydraulic turbines are operated more frequent and over longer periods of time in lower part load at off-design conditions. This leads to a more turbulent behavior and to higher requirements of the strength of stressed components (e.g. runner, guide or stay vanes). The modern advantages of computational capabilities regarding numerical investigations allow a precise prediction of appearing flow conditions and thereby induced strains in hydraulic machines. This paper focuses on the calculation of the unsteady pressure field of a high head Francis turbine with a specific speed of nq ≈ 24 min-1 and its impact on the structure at different operating conditions. In the first step, unsteady numerical flow simulations are performed with the open-source CFD software OpenFOAM. To obtain the appearing dynamic flow phenomena, the entire machine, consisting of the spiral casing, the stay vanes, the wicket gate, the runner and the draft tube, is taken into account. Additionally, a reduced model without the spiral casing and with a simplified inlet boundary is used. To evaluate the accuracy of the CFD simulations, operating parameters such as head and torque are compared with the results of site measurements carried out on the corresponding prototype machine. In the second part, the obtained pressure fields are used for a fluid-structure analysis with the open-source Finite Element software Code_Aster, to predict the static loads on the runner.

  11. Evaluation of two methods for measuring saturated hydraulic conductivity of soils under two vegetation covers

    Rubio, C.M.; Josa, R.; Poyatos, R.; Llorens, P.; Gallart, F.; Latron, J.; Ferrer, F.


    The main goal of this work is to determine and to evaluate the saturated hydraulic conductivity for a silt loam soil in field and laboratory conditions. the experimental area was located in the Vallcebre research catchment, in headwaters of the Llobregat River (NE Spain). Hydraulic conductivity was measured in the field using the Guelph permeameter and field saturated hydraulic conductivity (K{sub f}s) based on Elrick equation was calculated. The Guelph permeameter measures were made in two conditions (dry and wet) and in profiles below two vegetation covers (meadows and forest). To determine the saturated hydraulic conductivity at the laboratory (K{sub s}) the constant head permeameter was used. The average K{sub f}s values for the wet period was about 2 cm.h{sup -}1. During the dry period, both soil profiles presented higher values, about 7.5 cm.h{sup -}1. Under laboratory conditions, means observed K{sub s} values were between 12 and 25 cm.h{sup -}1. The relationship K{sub f}s/k{sub s} was of 0.1 cm.h{sup -}1 in wet conditions and about 0.4 cm.h{sup -}1 in dry conditions. The results indicated significant differences between both methods and between both seasons. differences can be explained by the anisotropy of soils as a consequence of vegetation root system that promotes preferential flows paths. (Author) 10 refs.

  12. Comparison among monitoring strategies to assess water flow dynamic and soil hydraulic properties in agricultural soils

    Javier Valdes-Abellan


    Full Text Available Abstract Irrigated agriculture is usually performed in semi-arid regions despite scarcity of water resources. Therefore, optimal irrigation management by monitoring the soil is essential, and assessing soil hydraulic properties and water flow dynamics is presented as a first measure. For this purpose, the control of volumetric water content, θ, and pressure head, h, is required. This study adopted two types of monitoring strategies in the same experimental plot to control θ and h in the vadose zone: i non-automatic and more time-consuming; ii automatic connected to a datalogger. Water flux was modelled with Hydrus-1D using the data collected from both acquisition strategies independently (3820 daily values for the automatic; less than 1000 for the non-automatic. Goodness-of-fit results reported a better adjustment in case of automatic sensors. Both model outputs adequately predicted the general trend of θ and h, but with slight differences in computed annual drainage (711 mm and 774 mm. Soil hydraulic properties were inversely estimated from both data acquisition systems. Major differences were obtained in the saturated volumetric water content, θs, and the n and α van Genuchten model shape parameters. Saturated hydraulic conductivity, Ks, shown lower variability with a coefficient of variation range from 0.13 to 0.24 for the soil layers defined. Soil hydraulic properties were better assessed through automatic data acquisition as data variability was lower and accuracy was higher.

  13. Comparison among monitoring strategies to assess water flow dynamic and soil hydraulic properties in agricultural soils

    Valdes-Abellan, J.; Jiménez-Martínez, J.; Candela, L.; Tamoh, K.


    Irrigated agriculture is usually performed in semi-arid regions despite scarcity of water resources. Therefore, optimal irrigation management by monitoring the soil is essential, and assessing soil hydraulic properties and water flow dynamics is presented as a first measure. For this purpose, the control of volumetric water content, θ, and pressure head, h, is required. This study adopted two types of monitoring strategies in the same experimental plot to control θ and h in the vadose zone: i) non-automatic and more time-consuming; ii) automatic connected to a datalogger. Water flux was modelled with Hydrus-1D using the data collected from both acquisition strategies independently (3820 daily values for the automatic; less than 1000 for the non-automatic). Goodness-of-fit results reported a better adjustment in case of automatic sensors. Both model outputs adequately predicted the general trend of θ and h, but with slight differences in computed annual drainage (711 mm and 774 mm). Soil hydraulic properties were inversely estimated from both data acquisition systems. Major differences were obtained in the saturated volumetric water content, θs, and the n and α van Genuchten model shape parameters. Saturated hydraulic conductivity, Ks, shown lower variability with a coefficient of variation range from 0.13 to 0.24 for the soil layers defined. Soil hydraulic properties were better assessed through automatic data acquisition as data variability was lower and accuracy was higher. (Author)

  14. Analytical and numerical simulations of a hydraulic fracturing experiment

    Zhou, M.Z.; Namiq, M.A.; Zhou, L.; Gou, Y. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. of Petroleum Engineering


    Based on simulations of a previously published hydraulic fracturing experiment performed by Casas et al. (2006), this paper presents the performance assessment of the famous analytical fracture 2D-models (PKN and KGD) and a 3D numerical model (FDM program FLAC3D of the ITASCA Inc.). Strain-softening models are used in the FLAC3D to describe the fracture creation and propagation as well as to present the material softening properties (permeability, tensile strength, cohesion, friction and dilation angel) as functions of the plastic strain. The results show that the numerical simulator has a much better performance and produces more reliable results than the analytical fracture models. However, numerical models have limitations and thus potential for further development. (orig.)

  15. One-year results of cemented bipolar radial head prostheses for comminuted radial head fractures

    Laun, Reinhold


    Full Text Available Introduction: Comminuted radial head fractures (Mason type III continue to pose a challenge to orthopedic surgeons. When internal fixation is not possible, radial head arthroplasty has been advocated as the treatment of choice. The purpose of this retrospective study was to evaluate clinical and radiological short-term results of patients with Mason type III radial head fractures treated with a cemented bipolar radial prosthesis. Methods: Twelve patients received cemented bipolar radial head hemiarthroplasty for comminuted radial head fractures. In all patients a CT scan was obtained prior to surgical treatment to assess all associated injuries. Postoperatively an early motion protocol was applied. All patients were evaluated clinically and radiologically at an average of 12.7 months.Results: According to the Mayo Modified Wrist Score, the Mayo Elbow Performance Score, the functional rating index of Broberg and Morrey, and the DASH Score good to excellent results were obtained. Grip strength and range of motion were almost at the level of the unaffected contralateral side. Patient satisfaction was high, no instability or signs of loosening of the implant, and only mild signs of osteoarthritis were seen.Conclusion: Overall good to excellent short-term results for primary arthroplasty for comminuted radial head fractures were observed. These encouraging results warrant the conduction of further studies with long-term follow-up and more cases to see if these short-term results can be maintained over time.

  16. Acute effects of partial-body cryotherapy on isometric strength: maximum handgrip strength evaluation.

    De Nardi, M; Pizzigalli, L; Benis, R; Caffaro, F; Cremasco, M Micheletti


    The aim of the study was to evaluate the influence of a single partial-body cryotherapy (PBC) session on the maximum handgrip strength (JAMAR Hydraulic Hand dynamometer). Two hundred healthy adults were randomized into a PBC group and a control group (50 males and 50 females in each group). After the initial handgrip strength test (T0), the experimental group performed a 150 seconds session of PBC (temperature range between -130 and -160 °C), whilst the control group stayed in a thermo neutral room (22.0 ± 0.5 °C). Immediately after, both groups performed another handgrip strength test (T1). Data underlined that both groups showed an increase in handgrip strength values, especially the experimental group (Control: T0=39.48 kg, T1=40.01 kg; PBC: T0=39.61 kg, T1=41.34 kg). The analysis reported also a statistical effect related to gender (F=491.99, Pstrength values compared with males (females=30.43 kg, males=52.27 kg). Findings provide the first evidence that a single session of PBC leads to the improvement of muscle strength in healthy people. The results of the study implies that PBC could be performed also before a training session or a sport competition, to increase hand isometric strength.

  17. Strength criterion for rocks under compressive-tensile stresses and its application

    Mingqing You


    Full Text Available Estimating in-situ stress with hydraulic borehole fracturing involves tensile strength of rock. Several strength criteria with three parameters result in tensile strengths with great differences, although they may describe the relation between strength of rock and confining pressure with low misfits. The exponential criterion provides acceptable magnitudes of tensile strengths for granites and over-estimates that for other rocks, but the criterion with tension cut-off is applicable to all rocks. The breakdown pressure will be lower than the shut-in pressure during hydraulic borehole fracturing, when the maximum horizontal principal stress is 2 times larger than the minor one; and it is not the peak value in the first cycle, but the point where the slope of pressure-time curve begins to decline.

  18. Evaluation of the Strength Variation of Normal and Lightweight Self-Compacting Concrete in Full Scale Walls

    Hosseinali, M.; Ranjbar, M. M.; Rezvani, S. M.


    The strength of cast concrete along the height and length of large structural members might vary due to inadequate compaction, segregation, bleeding, head pressure, and material type. The distribution of strength within a series of full scale reinforced concrete walls was examined using non...... strength variation and the relationship to the strength of standard cube samples. Investigation of the strength variation along the height of the wall showed that SCC mixes had better strength uniformity and that the NC mix had the greatest strength variation. There were no significant strength differences...... between mixtures along the length of the walls. Furthermore, different admixture replacements did not have a meaningful effect on the strength distribution....

  19. Strength and Balance Exercises

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Strength and Balance Exercises Updated:Sep 8,2016 If ... Be Safe While Being Active - Stretching & Flexibility Exercises - Strength & Balance Exercises - Problems & Solutions for Being Active - FAQs ...

  20. Hydraulic Conductivity Estimate via Tracer Test and Ensemble Kalman Filter Data Assimilation: Theoretical and Numerical Fundamentals

    Crestani, E.; Camporese, M.; Salandin, P.


    subsequent conditional generation. The performance of the method is carefully analyzed in terms of root mean square error of the reconstructed hydraulic log-conductivity field. Besides to highlight its weakness and strength, the results show that the proposed approach can represent an effective tool for describing the hydraulic conductivity distribution at the locale scale.

  1. Early Head Start Evaluation

    U.S. Department of Health & Human Services — Longitudinal information from an evaluation where children were randomly assigned to Early Head Start or community services as usual;direct assessments and...

  2. Computed Tomography (CT) -- Head

    Full Text Available ... you! Do you have a personal story about radiology? Share your patient story here Images × Image Gallery ... Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to ...

  3. Head and face reconstruction

    ... work together. Head and neck surgeons also perform craniofacial reconstruction operations. The surgery is done while you are deep asleep and pain-free (under general anesthesia ). The surgery may take ...

  4. Computed Tomography (CT) -- Head

    Full Text Available ... headaches, dizziness, and other symptoms of aneurysm, bleeding, stroke and brain tumors. It also helps your doctor ... scanning provides more detailed information on head injuries, stroke , brain tumors and other brain diseases than regular ...

  5. Computed Tomography (CT) -- Head

    Full Text Available ... a stroke, especially with a new technique called Perfusion CT. brain tumors. enlarged brain cavities (ventricles) in ... X-Ray and CT Exams Blood Clots CT Perfusion of the Head CT Angiography (CTA) Stroke Brain ...

  6. Computed Tomography (CT) -- Head

    Full Text Available ... traditional x-rays, particularly of soft tissues and blood vessels. CT scanning provides more detailed information on head injuries, stroke , brain tumors and other brain diseases than ...

  7. Computed Tomography (CT) -- Head

    Full Text Available ... special x-ray equipment to help assess head injuries, severe headaches, dizziness, and other symptoms of aneurysm, ... cancer. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. ...

  8. Computed Tomography (CT) -- Head

    Full Text Available ... headaches, dizziness, and other symptoms of aneurysm, bleeding, stroke and brain tumors. It also helps your doctor ... scanning provides more detailed information on head injuries, stroke , brain tumors and other brain diseases than regular ...

  9. Computed Tomography (CT) -- Head

    Full Text Available ... images of internal organs, bones, soft tissue and blood vessels provide greater detail than traditional x-rays, particularly of soft tissues and blood vessels. CT scanning provides more detailed information on head ...

  10. Head CT scan

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... hold your breath for short periods. A complete scan usually take only 30 seconds to a few ...

  11. Head Start Impact Study

    U.S. Department of Health & Human Services — Nationally representative, longitudinal information from an evaluation where children were randomly assigned to Head Start or community services as usual;direct...

  12. Computed Tomography (CT) -- Head

    Full Text Available ... special x-ray equipment to help assess head injuries, severe headaches, dizziness, and other symptoms of aneurysm, ... cancer. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. ...

  13. Strength Training for Girls.

    Connaughton, Daniel; Connaughton, Angela; Poor, Linda


    Strength training can be fun, safe, and appropriate for young girls and women and is an important component of any fitness program when combined with appropriate cardiovascular and flexibility activities. Concerns and misconceptions regarding girls' strength training are discussed, presenting general principles of strength training for children…

  14. Strength Training for Girls.

    Connaughton, Daniel; Connaughton, Angela; Poor, Linda


    Strength training can be fun, safe, and appropriate for young girls and women and is an important component of any fitness program when combined with appropriate cardiovascular and flexibility activities. Concerns and misconceptions regarding girls' strength training are discussed, presenting general principles of strength training for children…

  15. Head and neck teratomas

    Shah, Ajaz; Latoo, Suhail; Ahmed, Irshad; Malik, Altaf H


    Teratomas are complex lesions composed of diverse tissues from all 3 germinal cell layers and may exhibit variable levels of maturity. Head and neck teratomas are most commonly cervical with the oropharynx (epignathus) being the second commonest location. In this article, clinical presentation, behaviour and associated significance of head and neck teratomas have been highlightened. Because of their obscure origin, bizarre microscopic appearance, unpredictable behaviour and often dramatic cli...

  16. Estimating Saturated Hydraulic Conductivity from Surface Ground-Penetrating Radar Monitoring of Infiltration

    Léger, Emmanuel; Coquet, Yves


    In this study we used Hydrus-1D to simulate water infiltration from a ring infiltrometer. We generated water content profiles at each time step of infiltration, based on a particular value of the saturated hydraulic conductivity while knowing the other van Genuchten parameters. Water content profiles were converted to dielectric permittivity profiles using the Complex Refractive Index Method relation. We then used the GprMax suite of programs to generate radargrams and to follow the wetting front using arrival time of electromagnetic waves recorded by a Ground-Penetrating Radar (GPR). Theoretically, the depth of the inflection point of the water content profile simulated at any infiltration time step is related to the peak of the reflected amplitude recorded in the corresponding trace in the radargram. We used this relationship to invert the saturated hydraulic conductivity for constant and falling head infiltrations. We present our method on synthetic examples and on two experiments carried out on sand. We f...

  17. Biomechanics of Heading a Soccer Ball: Implications for Player Safety

    Charles F. Babbs


    Full Text Available To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton�s second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established criteria for serious head injury from the motor vehicle crash literature. The results suggest heading is usually safe but occasionally dangerous, depending on key characteristics of both the player and the ball. Safety is greatly improved when players head the ball with greater effective body mass, which is determined by a player�s size, strength, and technique. Smaller youth players, because of their lesser body mass, are more at risk of potentially dangerous headers than are adults, even when using current youth size balls. Lower ball inflation pressure reduces risk of dangerous head accelerations. Lower pressure balls also have greater “touch” and “playability”, measured in terms of contact time and contact area between foot and ball during a kick. Focus on teaching proper technique, the re-design of age-appropriate balls for young players with reduced weight and inflation pressure, and avoidance of head contact with fast, rising balls kicked at close range can substantially reduce risk of subtle brain injury in players who head soccer balls.

  18. Biomechanics of heading a soccer ball: implications for player safety.

    Babbs, C F


    To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton's second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established criteria for serious head injury from the motor vehicle crash literature. The results suggest heading is usually safe but occasionally dangerous, depending on key characteristics of both the player and the ball. Safety is greatly improved when players head the ball with greater effective body mass, which is determined by a player"s size, strength, and technique. Smaller youth players, because of their lesser body mass, are more at risk of potentially dangerous headers than are adults, even when using current youth size balls. Lower ball inflation pressure reduces risk of dangerous head accelerations. Lower pressure balls also have greater "touch" and "playability", measured in terms of contact time and contact area between foot and ball during a kick. Focus on teaching proper technique, the re-design of age-appropriate balls for young players with reduced weight and inflation pressure, and avoidance of head contact with fast, rising balls kicked at close range can substantially reduce risk of subtle brain injury in players who head soccer balls.

  19. Effects of First-Order Approximations on Head and Specific Discharge Covariances in High-Contrast Log Conductivity

    van Lent, Thomas; Kitanidis, Peter K.


    The hydraulic head and the specific discharge fluctuations depend nonlinearly on the hydraulic conductivity. However, the methods most commonly used in the stochastic analysis of groundwater flow are based upon the linearization of these relations. In this paper we apply a numerical spectral approach to investigate the range of validity of the small perturbation approximation for head and specific discharge moments in two-dimensional finite domains. We find that the small perturbation approximation tends to underestimate the variance of large-scale head and specific discharge fluctuations and error increases with increasing log-conductivity variance and increasing domain size. The head fluctuations do not appear ergodic even when the small perturbation approximation predicts they will be ergodic. The specific discharge fluctuations, on the other hand, do appear ergodic. The small perturbation approximation performs well in estimating specific discharge variance in the longitudinal direction but significantly underestimates transverse specific discharge variance.

  20. Thermal-hydraulic modeling and analysis of hydraulic system by pseudo-bond graph

    胡均平; 李科军


    To increase the efficiency and reliability of the thermodynamics analysis of the hydraulic system, the method based on pseudo-bond graph is introduced. According to the working mechanism of hydraulic components, they can be separated into two categories: capacitive components and resistive components. Then, the thermal-hydraulic pseudo-bond graphs of capacitive C element and resistance R element were developed, based on the conservation of mass and energy. Subsequently, the connection rule for the pseudo-bond graph elements and the method to construct the complete thermal-hydraulic system model were proposed. On the basis of heat transfer analysis of a typical hydraulic circuit containing a piston pump, the lumped parameter mathematical model of the system was given. The good agreement between the simulation results and experimental data demonstrates the validity of the modeling method.

  1. Combining multi-objective optimization and bayesian model averaging to calibrate forecast ensembles of soil hydraulic models

    Vrugt, Jasper A [Los Alamos National Laboratory; Wohling, Thomas [NON LANL


    Most studies in vadose zone hydrology use a single conceptual model for predictive inference and analysis. Focusing on the outcome of a single model is prone to statistical bias and underestimation of uncertainty. In this study, we combine multi-objective optimization and Bayesian Model Averaging (BMA) to generate forecast ensembles of soil hydraulic models. To illustrate our method, we use observed tensiometric pressure head data at three different depths in a layered vadose zone of volcanic origin in New Zealand. A set of seven different soil hydraulic models is calibrated using a multi-objective formulation with three different objective functions that each measure the mismatch between observed and predicted soil water pressure head at one specific depth. The Pareto solution space corresponding to these three objectives is estimated with AMALGAM, and used to generate four different model ensembles. These ensembles are post-processed with BMA and used for predictive analysis and uncertainty estimation. Our most important conclusions for the vadose zone under consideration are: (1) the mean BMA forecast exhibits similar predictive capabilities as the best individual performing soil hydraulic model, (2) the size of the BMA uncertainty ranges increase with increasing depth and dryness in the soil profile, (3) the best performing ensemble corresponds to the compromise (or balanced) solution of the three-objective Pareto surface, and (4) the combined multi-objective optimization and BMA framework proposed in this paper is very useful to generate forecast ensembles of soil hydraulic models.

  2. A hybrid inverse method for hydraulic tomography in fractured and karstic media

    Wang, Xiaoguang; Jardani, Abderrahim; Jourde, Hervé


    We apply a stochastic Newton (SN) approach to solve a high-dimensional hydraulic inverse problem in highly heterogeneous geological media. By recognizing the connection between the cost function of deterministic optimizations and the posterior probability density of stochastic inversions, the Markov chain Monte Carlo (MCMC) sampler of SN is constructed by two parts: a deterministic part, which corresponds to a Newton step of deterministic optimization, and a stochastic part, which is a Gaussian distribution with the inverse of the local Hessian as the covariance matrix. The hybrid inverse method exploits the efficient tools for fast solution of deterministic inversions to improve the efficiency of the MCMC sampler. To address the ill-posedness of the inverse problem, a priori models, generated by a transition-probability geostatistical method, and conditioned to inter-well connection data, are used as regularization constraints. The effectiveness of the stochastic Newton method is first demonstrated by a synthetic test. The transmissivity field of the synthetic model is highly heterogeneous, and includes sharp variations. The inverse approach was then applied to a field hydraulic tomography investigation in a fractured and karstified aquifer to reconstruct its transmissivity field from a collection of real hydraulic head measurements. From the inversions, a series of transmissivity fields that produce good correlations between the inverted and the measured hydraulic heads were obtained. The inverse approach produced slightly different a posteriori transmissivity patterns for different a priori structure models of transmissivity; however, the trend and location of the high-transmissivity channels are consistent among various realizations. In addition, the uncertainty associated with each realization of the inverted transmissivity fields was quantified.

  3. Analyzing the effects of geological and parameter uncertainty on prediction of groundwater head and travel time

    X. He


    Full Text Available Uncertainty of groundwater model predictions has in the past mostly been related to uncertainty in the hydraulic parameters, whereas uncertainty in the geological structure has not been considered to the same extent. Recent developments in theoretical methods for quantifying geological uncertainty have made it possible to consider this factor in groundwater modeling. In this study we have applied the multiple-point geostatistical method (MPS integrated in the Stanford Geostatistical Modeling Software (SGeMS for exploring the impact of geological uncertainty on groundwater flow patterns for a site in Denmark. Realizations from the geostatistical model were used as input to a groundwater model developed from Modular three-dimensional finite-difference ground-water model (MODFLOW within the Groundwater Modeling System (GMS modeling environment. The uncertainty analysis was carried out in three scenarios involving simulation of groundwater head distribution and travel time. The first scenario implied 100 stochastic geological models all assigning the same hydraulic parameters for the same geological units. In the second scenario the same 100 geological models were subjected to model optimization, where the hydraulic parameters for each of them were estimated by calibration against observations of hydraulic head and stream discharge. In the third scenario each geological model was run with 216 randomized sets of parameters. The analysis documented that the uncertainty on the conceptual geological model was as significant as the uncertainty related to the embedded hydraulic parameters.

  4. Strength Modeling Report

    Badler, N. I.; Lee, P.; Wong, S.


    Strength modeling is a complex and multi-dimensional issue. There are numerous parameters to the problem of characterizing human strength, most notably: (1) position and orientation of body joints; (2) isometric versus dynamic strength; (3) effector force versus joint torque; (4) instantaneous versus steady force; (5) active force versus reactive force; (6) presence or absence of gravity; (7) body somatotype and composition; (8) body (segment) masses; (9) muscle group envolvement; (10) muscle size; (11) fatigue; and (12) practice (training) or familiarity. In surveying the available literature on strength measurement and modeling an attempt was made to examine as many of these parameters as possible. The conclusions reached at this point toward the feasibility of implementing computationally reasonable human strength models. The assessment of accuracy of any model against a specific individual, however, will probably not be possible on any realistic scale. Taken statistically, strength modeling may be an effective tool for general questions of task feasibility and strength requirements.

  5. The strength compass

    Ledertoug, Mette Marie

    Individual paper presentation: The ‘Strength Compass’. The results of a PhDresearch project among schoolchildren (age 6-16) identifying VIAstrengths concerning age, gender, mother-tongue-langue and possible child psychiatric diagnosis. Strengths-based interventions in schools have a theoretical...... foundation in research in VIA-strengths by Seligman & Peterson (2004) and in research on strengths by Linley (2008). Based on this research the VIA-test was created for adults and later for children and youths from the age of 10. For children younger than 10 years of age Peterson & Park (2011) have made...... interviews with the parents. For younger children there has been no possibility to test for strengths. In a Danish PhD project a tool to map children’s strengths was needed for children aged 6-16 and with permission from the VIA-institute ‘The Strength Compass’ was made in cooperation with The Danish...

  6. Bone properties of the humeral head and resistance to screw cutout

    Frich, L. H.; Jensen, N. C.


    anisotropy was also found. We found in particular a lower bone strength and density in the posterior and inferior regions of the humeral head. A rapid decline in bone strength within a few mm below a relatively thin subchondral plate was also reported. Clinical Relevance: We have in this paper explored some...... screw directions will predictably place screws in areas of the humeral head comprising low density and low strength cancellous bone. New concepts of plates and plating techniques for the surgical treatment of complex fractures of the proximal humerus should take bone distribution, strength...

  7. Effect of Natural Fractures on Hydraulic Fracturing

    Ben, Y.; Wang, Y.; Shi, G.


    Hydraulic Fracturing has been used successfully in the oil and gas industry to enhance oil and gas production in the past few decades. Recent years have seen the great development of tight gas, coal bed methane and shale gas. Natural fractures are believed to play an important role in the hydraulic fracturing of such formations. Whether natural fractures can benefit the fracture propagation and enhance final production needs to be studied. Various methods have been used to study the effect of natural fractures on hydraulic fracturing. Discontinuous Deformation Analysis (DDA) is a numerical method which belongs to the family of discrete element methods. In this paper, DDA is coupled with a fluid pipe network model to simulate the pressure response in the formation during hydraulic fracturing. The focus is to study the effect of natural fractures on hydraulic fracturing. In particular, the effect of rock joint properties, joint orientations and rock properties on fracture initiation and propagation will be analyzed. The result shows that DDA is a promising tool to study such complex behavior of rocks. Finally, the advantages of disadvantages of our current model and future research directions will be discussed.

  8. Microbial effect on soil hydraulic properties

    Furman, Alex; Rosenzweig, Ravid; Volk, Elazar; Rosenkranz, Hella; Iden, Sascha; Durner, Wolfgang


    Although largely ignored, the soil contains large amount of biofilms (attached microbes) that can affect many processes. While biochemical processes are studied, biophysical processes receive only little attention. Biofilms may occupy some of the pore space, and by that affect the soil hydraulic properties. This effect on unsaturated soils, however, was not intensively studied. In this research we directly measure the hydraulic properties, namely the soil's unsaturated hydraulic conductivity function and retention curve, for soils containing real biofilm. To do that we inoculate soil with biofilm-forming bacteria and incubate it with sufficient amounts of nutrient until biofilm is formed. The hydraulic properties of the incubated soil are then measured using several techniques, including multi-step outflow and evaporation method. The longer measurements (evaporation method) are conducted under refrigeration conditions to minimize microbial activity during the experiment. The results show a clear effect of the biofilm, where the biofilm-affected soil (sandy loam in our case) behaves like a much finer soil. This qualitatively makes sense as the biofilm generates an effective pore size distribution that is characterized by smaller pores. However, the effect is much more complex and needs to be studied carefully considering (for example) dual porosity models. We compare our preliminary results with other experiments, including flow-through column experiments and experiments with biofilm analogues. Clearly a better understanding of the way microbial activity alters the hydraulic properties may help designing more efficient bioremediation, irrigation, and other soil-related processes.

  9. Vibration Isolation for Parallel Hydraulic Hybrid Vehicles

    The M. Nguyen


    Full Text Available In recent decades, several types of hybrid vehicles have been developed in order to improve the fuel economy and to reduce the pollution. Hybrid electric vehicles (HEV have shown a significant improvement in fuel efficiency for small and medium-sized passenger vehicles and SUVs. HEV has several limitations when applied to heavy vehicles; one is that larger vehicles demand more power, which requires significantly larger battery capacities. As an alternative solution, hydraulic hybrid technology has been found effective for heavy duty vehicle because of its high power density. The mechanical batteries used in hydraulic hybrid vehicles (HHV can be charged and discharged remarkably faster than chemical batteries. This feature is essential for heavy vehicle hybridization. One of the main problems that should be solved for the successful commercialization of HHV is the excessive noise and vibration involving with the hydraulic systems. This study focuses on using magnetorheological (MR technology to reduce the noise and vibration transmissibility from the hydraulic system to the vehicle body. In order to study the noise and vibration of HHV, a hydraulic hybrid subsystem in parallel design is analyzed. This research shows that the MR elements play an important role in reducing the transmitted noise and vibration to the vehicle body. Additionally, locations and orientations of the isolation system also affect the efficiency of the noise and vibration mitigation. In simulations, a skyhook control algorithm is used to achieve the highest possible effectiveness of the MR isolation system.

  10. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  11. Missouri: Early Head Start Initiative

    Center for Law and Social Policy, Inc. (CLASP), 2012


    Missouri's Early Head Start/Child Care Partnership Project expands access to Early Head Start (EHS) services for children birth to age 3 by developing partnerships between federal Head Start, EHS contractors, and child care providers. Head Start and EHS contractors that participate in the initiative provide services through community child care…

  12. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  13. Economics of head injuries

    Singh Manmohan


    Full Text Available Summary: Head injuries account for significant proportion of neurosurgical admissions and bed occupancy. Patients with head injuries also consume significant proportions of neurosurgical resources. A prospective 6-month study has been carried out to evaluate the expenditure incurred on head injury patients in a modern neurosurgical center equipped with state of the art infrastructure. Costing areas included wages / salaries of health care personnel, cost of medicines / surgical items / crystalloids, general store items, stationary, all investigation charges, equipment cost, overhead building cost, maintenance cost, electricity and water charges and cost of medical gases, air conditioning and operation theatre expenses. Expenditure in each area was calculated and apportioned to each bed. The statistical analysis was done using X2 test. The cost of stay in ward was found to be Rs. 1062 / bed / day and in neurosurgical ICU Rs. 3082 / bed / day. The operation theatre cost for each surgery was Rs. 11948. The cost of hospital stay per day for minor, moderate and severe head injury group was found to be Rs. 1921, Rs. 2569 and Rs. 2713 respectively. The patients who developed complications, the cost of stay per day in the hospital were Rs. 2867. In the operative group, the cost of hospital stay per day was Rs. 3804. The total expenditure in minor head injury was Rs. 7800 per patient, in moderate head injury was Rs. 22172 per patient, whereas in severe head injury, it was found to be Rs. 32852 per patient. Patients who underwent surgery, the total cost incurred was Rs. 33100 per operated patient.

  14. A Computational Model of Hydraulic Volume Displacement Drive

    V. N. Pil'gunov


    Full Text Available The paper offers a computational model of industrial-purpose hydraulic drive with two hydraulic volume adjustable working chamber machines (pump and motor. Adjustable pump equipped with the pressure control unit can be run together with several adjustable hydraulic motors on the principle of three-phase hydraulic socket-outlet with high-pressure lines, drain, and drainage system. The paper considers the pressure-controlled hydrostatic transmission with hydraulic motor as an output link. It shows a possibility to create a saving hydraulic drive using a functional tie between the adjusting parameters of the pump and hydraulic motor through the pressure difference, torque, and angular rate of the hydraulic motor shaft rotation. The programmable logic controller can implement such tie. The Coulomb and viscous frictions are taken into consideration when developing a computational model of the hydraulic volume displacement drive. Discharge balance considers external and internal leakages in equivalent clearances of hydraulic machines, as well as compression loss volume caused by hydraulic fluid compressibility and deformation of pipe walls. To correct dynamic properties of hydraulic drive, the paper offers that in discharge balance are included the additional regulated external leakages in the open circuit of hydraulic drive and regulated internal leakages in the closed-loop circuit. Generalized differential equations having functional multipliers and multilinked nature have been obtained to describe the operation of hydraulic positioning and speed drive with two hydraulic volume adjustable working chamber machines. It is shown that a proposed computational model of hydraulic drive can be taken into consideration in development of LS («Load-Sensing» drives, in which the pumping pressure is tuned to the value required for the most loaded slave motor to overcome the load. Results attained can be used both in designing the industrial-purpose heavy

  15. Evaluating Freeze-Thaw Deterioration with Tensile Strength

    Komar, A. J. K.; Boyd, A. J.


    Freeze-thaw damage is one of the leading contributors to infrastructure deterioration in temperate northern climates. Deterioration caused by freeze-thaw cycling is primarily induced by hydraulic pressures within the hydrated cement paste matrix that cause tensile cracking. Such damage should, therefore, be more effectively detected with tensile testing. This work presents the detection and evaluation of ongoing freeze-thaw (F/T) damage in plain concrete cylinders using the pressure tensile strength test, as it compares to compressive strength evaluation. Pressure tension test results exhibited significantly higher levels of deterioration compared to compression testing, with the samples losing up to 90% of their undamaged tensile capacity. Moreover, it was shown that tensile strength testing is far more sensitive to freeze-thaw deterioration, evidenced by a significant drop in the tensile to compressive strength ratio to below 5%.

  16. Measurement and evaluation of static characteristics of rotary hydraulic motor

    Hružík Lumír


    Full Text Available The paper describes experimental equipment for measurement of static characteristics of rotary hydraulic motor. It is possible to measure flow, pressure, temperature, speed and torque by means of this equipment. It deals with measurement of static characteristics of a gear rotary hydraulic motor. Mineral oil is used as hydraulic liquid in this case. Flow, torque and speed characteristics are evaluated from measured parameters. Measured mechanical-hydraulic, flow and total efficiencies of the rotary hydraulic motor are adduced in the paper. It is possible to diagnose technical conditions of the hydraulic motor (eventually to recommend its exchange from the experimental measurements.

  17. Promoting water hydraulics in Malaysia: A green educational approach

    Yusof, Ahmad Anas; Zaili, Zarin Syukri; Hassan, Siti Nor Habibah; Tuan, Tee Boon; Saadun, Mohd Noor Asril; Ibrahim, Mohd Qadafie


    In promoting water hydraulics in Malaysia, this paper presents research development of water hydraulics educational training system for secondary and tertiary levels in Malaysia. Water hydraulics trainer with robotic attachment has been studied in order to promote the usefulness of such educational tools in promoting sustainability and green technology in the country. The trainer is being developed in order to allow constructive curriculum development and continuous marketing research for the effectiveness and usefulness of using water in hydraulic power trainer. The research on water-based hydraulic trainer is now possible with the current development in water hydraulics technology.

  18. Hydraulic characterization of hydrothermally altered Nopal tuff

    Green, R.T.; Meyer-James, K.A. [Southwest Research Institute, San Antonio, TX (United States); Rice, G. [George Rice and Associates, San Antonio, TX (United States)


    Understanding the mechanics of variably saturated flow in fractured-porous media is of fundamental importance to evaluating the isolation performance of the proposed high-level radioactive waste repository for the Yucca Mountain site. Developing that understanding must be founded on the analysis and interpretation of laboratory and field data. This report presents an analysis of the unsaturated hydraulic properties of tuff cores from the Pena Blanca natural analog site in Mexico. The basic intent of the analysis was to examine possible trends and relationships between the hydraulic properties and the degree of hydrothermal alteration exhibited by the tuff samples. These data were used in flow simulations to evaluate the significance of a particular conceptual (composite) model and of distinct hydraulic properties on the rate and nature of water flow.

  19. Simulation of a Hydraulic Pump Control Valve

    Molen, G. Vander; Akers, A.


    This paper describes the mode of operation of a control valve assembly that is used with a hydraulic pump. The operating system of the valve is modelled in a simplified form, and an analogy for hydraulic resonance of the pressure sensing system is presented. For the control valve investigated, air entrainment, length and diameter of the resonator neck, and valve mass produced the greatest shift in resonant frequency. Experimental work was conducted on the hydraulic system so that the resonance levels and frequencies could be measured and the accuracy of the theory verified. The results obtained make it possible to evaluate what changes to any of the variables considered would be most effective in driving the second harmonic frequency above the operating range.

  20. Soil Structure and Saturated Hydraulic Conductivity

    Houskova, B.; Nagy, V.

    The role of soil structure on saturated hydraulic conductivity changes is studied in plough layers of texturally different soils. Three localities in western part of Slovakia in Zitny ostrov (Corn Island) were under investigation: locality Kalinkovo with light Calcaric Fluvisol (FAO 1970), Macov with medium heavy Calcari-mollic Fluvisol and Jurova with heavy Calcari-mollic Fluvisol. Soil structure was determined in dry as well as wet state and in size of macro and micro aggregates. Saturated hydraulic conductivity was measured by the help of double ring method. During the period of ring filling the soil surface was protected against aggregates damage by falling water drops. Spatial and temporal variability of studied parameters was evaluated. Cultivated crops were ensilage maize at medium heavy and heavy soil and colza at light soil. Textural composition of soil and actual water content at the beginning of measurement are one of major factor affecting aggregate stability and consequently also saturated hydraulic conductivity.

  1. Universal asymptotic umbrella for hydraulic fracture modeling

    Linkov, Aleksandr M


    The paper presents universal asymptotic solution needed for efficient modeling of hydraulic fractures. We show that when neglecting the lag, there is universal asymptotic equation for the near-front opening. It appears that apart from the mechanical properties of fluid and rock, the asymptotic opening depends merely on the local speed of fracture propagation. This implies that, on one hand, the global problem is ill-posed, when trying to solve it as a boundary value problem under a fixed position of the front. On the other hand, when properly used, the universal asymptotics drastically facilitates solving hydraulic fracture problems (both analytically and numerically). We derive simple universal asymptotics and comment on their employment for efficient numerical simulation of hydraulic fractures, in particular, by well-established Level Set and Fast Marching Methods.


    YE Fei; GAO Xue-ping


    The hydraulic characteristics at the side inlet/outlet of pumped storage plants is studied by numerical simulations, covering the flow distribution, head loss, vortex, and others.Based on the physical model test, the realizable k - ε turbulence model is used in the 3-D simulation of the side inlet/outlet.A new scheme is suggested to obtain the uneven flow distribution over three branch orifices.The variation of the free surface with the reservoir water level under the pumped condition is simulated, with results consistent with the experimental results.

  3. Laboratory evaporation experiments in undisturbed peat columns for determining peat soil hydraulic properties

    Dettmann, U.; Frahm, E.; Bechtold, M.


    Knowledge about hydraulic properties of organic soils is crucial for the interpretation of the hydrological situation in peatlands. This in turn is the basis for designing optimal rewetting strategies, for assessing the current and future climatic water balance and for quantifying greenhouse gas emissions of CO2, CH4 and N2O, which are strongly controlled by the depth of the peat water table. In contrast to mineral soils, the hydraulic properties of organic soils differ in several aspects. Due to the high amount of organic components, strong heterogeneity, and shrinkage and swelling of peat, accompanied by changing soil volume and bulk density, the applicability of standard hydraulic functions developed for mineral soils for describing peat soil moisture dynamics is often questioned. Hence, the objective of this study was to investigate the applicability of the commonly applied van Genuchten-Mualem (VGM) parameterization and to evaluate model errors for various peat types. Laboratory column experiments with undisturbed peat soils (diameter: 30 cm, height: 20 cm) from 5 different peatlands in Germany were conducted. In numerical simulations using HYDRUS-1D the experimental data were used for an inverse estimation of the soil hydraulic parameters. Using the VGM parameterization, the model errors between observed and measured pressure heads were quantified with a root mean square error (RMSE) of 20 - 65 cm. The RMSE increased for soils with higher organic carbon content and higher porosity. Optimizing the VGM 'tortuosity' parameter (τ) instead of fixing it to its default of 0.5 strongly reduced the RMSE, especially for the soils that showed high pressure head gradients during the experiment. Due to the fact, that very negative pressure heads in peatlands occur rarely, we reduced the range of pressured heads in the inversion to a 'field-relevant' range from 0 to -200 cm which strongly reduced the RMSE to 6 - 12 cm and makes the VGM parameterization applicable for all


    ZHANG Jun; XU Shao-hui; LIU Jian-li; ZHANG Jia-bao


    Transient outflow experiments coupling with an inverse method are promising to derive soil hydraulic information. The water retention curves obtained from one-step and multi-step outflow experiments were compared with those from the pressure cell method. We found that in one-step experiments the increment of pressure would reduce the non-uniqueness of inverse technique and that in multi-step experiment the combination of cumulative outflow with pressure head in the objective function would improve the final estimation and also reduce the non-uniqueness of inverse problem.

  5. Numerical study of rotor-stator interactions in a hydraulic turbine with Foam-extend

    Romain, Cappato; Guibault, François; Devals, Christophe; Nennemann, Bernd


    In the development of high head hydraulic turbines, vibrations are one of the critical problems. In Francis turbines, pressure fluctuations occur at the interface between the blades of the runner and guide vanes. This rotor-stator interaction can be responsible for fatigue failures and cracks. Although the flow inside the turbomachinery is complex, and the unsteadiness makes it difficult to model, the choice of an appropriate setup enables the study of this phenomenon. This study validates a numerical setup of the Foam-extend open source software for rotor-stator simulations. Pressure fluctuations results show a good correspondence with data from experiments.

  6. Detection of QTL for exudation rate at ripening stage in rice and its contribution to hydraulic conductance.

    Yamamoto, Toshio; Suzuki, Tadafumi; Suzuki, Kenji; Adachi, Shunsuke; Sun, Jian; Yano, Masahiro; Ookawa, Taiichiro; Hirasawa, Tadashi


    Dry matter production of crops is determined by how much light they intercept and how efficiently they use it for carbon fixation; i.e., photosynthesis. The high-yielding rice cultivar, Akenohoshi, maintains a high photosynthetic rate in the middle of the day owing to its high hydraulic conductance in comparison with the elite commercial rice cultivar, Koshihikari. We developed 94 recombinant inbred lines derived from Akenohoshi and Koshihikari and measured their exudation rate to calculate hydraulic conductance to osmotic water transport in a paddy field. A quantitative trait locus (QTL) for exudation rate was detected on the long arm of chromosome 2 at the heading and ripening stages. We developed chromosome segment substitution lines which carried Akenohoshi segments in the Koshihikari genetic background, and measured hydraulic conductance to both osmotic and passive water transport. The QTL was confirmed to be located within a region of about 4.2Mbp on the distal end of long arm of chromosome 2. The Akenohoshi allele increased root surface area and hydraulic conductance, but didn't increase hydraulic conductivity of a plant.

  7. Self-potential observations during hydraulic fracturing

    Moore, Jeffrey R.; Glaser, Steven D.


    The self-potential (SP) response during hydraulic fracturing of intact Sierra granite was investigated in the laboratory. Excellent correlation of pressure drop and SP suggests that the SP response is created primarily by electrokinetic coupling. For low pressures, the variation of SP with pressure drop is linear, indicating a constant coupling coefficient (Cc) of -200 mV/MPa. However for pressure drops >2 MPa, the magnitude of the Cc increases by 80% in an exponential trend. This increasing Cc is related to increasing permeability at high pore pressures caused by dilatancy of micro-cracks, and is explained by a decrease in the hydraulic tortuosity. Resistivity measurements reveal a decrease of 2% prior to hydraulic fracturing and a decrease of {approx}35% after fracturing. An asymmetric spatial SP response created by injectate diffusion into dilatant zones is observed prior to hydraulic fracturing, and in most cases this SP variation revealed the impending crack geometry seconds before failure. At rupture, injectate rushes into the new fracture area where the zeta potential is different than in the rock porosity, and an anomalous SP spike is observed. After fracturing, the spatial SP distribution reveals the direction of fracture propagation. Finally, during tensile cracking in a point load device with no water flow, a SP spike is observed that is caused by contact electrification. However, the time constant of this event is much less than that for transients observed during hydraulic fracturing, suggesting that SP created solely from material fracture does not contribute to the SP response during hydraulic fracturing.

  8. Measurement and modeling of unsaturated hydraulic conductivity

    Perkins, Kim S.; Elango, Lakshmanan


    The unsaturated zone plays an extremely important hydrologic role that influences water quality and quantity, ecosystem function and health, the connection between atmospheric and terrestrial processes, nutrient cycling, soil development, and natural hazards such as flooding and landslides. Unsaturated hydraulic conductivity is one of the main properties considered to govern flow; however it is very difficult to measure accurately. Knowledge of the highly nonlinear relationship between unsaturated hydraulic conductivity (K) and volumetric water content is required for widely-used models of water flow and solute transport processes in the unsaturated zone. Measurement of unsaturated hydraulic conductivity of sediments is costly and time consuming, therefore use of models that estimate this property from more easily measured bulk-physical properties is common. In hydrologic studies, calculations based on property-transfer models informed by hydraulic property databases are often used in lieu of measured data from the site of interest. Reliance on database-informed predicted values with the use of neural networks has become increasingly common. Hydraulic properties predicted using databases may be adequate in some applications, but not others. This chapter will discuss, by way of examples, various techniques used to measure and model hydraulic conductivity as a function of water content, K. The parameters that describe the K curve obtained by different methods are used directly in Richards’ equation-based numerical models, which have some degree of sensitivity to those parameters. This chapter will explore the complications of using laboratory measured or estimated properties for field scale investigations to shed light on how adequately the processes are represented. Additionally, some more recent concepts for representing unsaturated-zone flow processes will be discussed.

  9. Large-eddy simulation in hydraulics

    Rodi, Wolfgang


    Complex turbulence phenomena are of great practical importance in hydraulics, including environmental flows, and require advanced methods for their successful computation. The Large Eddy Simulation (LES), in which the larger-scale turbulent motion is directly resolved and only the small-scale motion is modelled, is particularly suited for complex situations with dominant large-scale structures and unsteadiness. Due to the increasing computer power, LES is generally used more and more in Computational Fluid Dynamics. Also in hydraulics, it offers great potential, especially for near-field probl

  10. Mineral resource of the month: hydraulic cement

    van Oss, Hendrik G.


    Hydraulic cements are the binders in concrete and most mortars and stuccos. Concrete, particularly the reinforced variety, is the most versatile of all construction materials, and most of the hydraulic cement produced worldwide is portland cement or similar cements that have portland cement as a basis, such as blended cements and masonry cements. Cement typically makes up less than 15 percent of the concrete mix; most of the rest is aggregates. Not counting the weight of reinforcing media, 1 ton of cement will typically yield about 8 tons of concrete.

  11. Pediatric head injury.

    Tulipan, N


    Pediatric head injury is a public health problem that exacts a high price from patients, their families and society alike. While much of the brain damage in head-injured patients occurs at the moment of impact, secondary injuries can be prevented by aggressive medical and surgical intervention. Modern imaging devices have simplified the task of diagnosing intracranial injuries. Recent advances in monitoring technology have made it easier to assess the effectiveness of medical therapy. These include intracranial pressure monitoring devices that are accurate and safe, and jugular bulb monitoring which provides a continuous, qualitative measure of cerebral blood flow. The cornerstones of treatment remain hyperventilation and osmotherapy. Despite maximal treatment, however, the mortality and morbidity associated with pediatric head injury remains high. Reduction of this mortality and morbidity will likely depend upon prevention rather than treatment.

  12. Enhanced shear strength of sodium bentonite using frictional additives

    Schmitt, K.E. [GeoSyntec Consultants, Huntington Beach, CA (United States); Bowders, J.J.; Gilbert, R.B. [Univ. of Texas, Austin, TX (United States); Daniel, D.E. [Univ. of Illinois, Urbana, IL (United States)


    One of the most important obstacles to using geosynthetic clay liners (GCLs) in landfill cover systems is the low shear strength provided by the bentonitic portion of the GCL. In this study, the authors propose that granular, frictional materials might be added to the bentonite to form an admixture that would have greater shear strength than the bentonite alone while still raining low hydraulic conductivity. Bentonite was mixed with two separate granular additives, expanded shale and recycled to form mixtures consisting of 20-70% bentonite by weight. In direct shear tests at normal stresses of 34.5-103.5 kPa, effective friction angles were measured as 45{degrees} for the expanded 36{degrees} for the recycled glass, and 7{degrees} for the hydrated granular bentonite. The strength of the expanded shale mixtures increased nearly linearly as the percentage shale in the mixture increased, to 44{degrees} for a bentonite mixture with 80% shale. The addition of recycled glass showed little effect on the shear strength of the mixtures of glass and bentonite. Hydraulic conductivity measurements for both types of mixtures indicated a linear increase with log(k) as the amount of granular additive increased. For applications involving geosynthetic clay liners for cover systems, a mixture of 40% expanded shale and 60% bentonite is recommended, although further testing must be done. The 40/60 mixture satisfies the hydraulic equivalency requirement, with k = 5.1X10{sup -9} cm/sec, while increasing the shear strength parameters of the bentonitic mixture to {phi}{prime} = 17{degrees} and c{prime} = 0.

  13. Interrelations among the soil-water retention, hydraulic conductivity, and suction-stress characteristic curves

    Lu, Ning; Kaya, Murat; Godt, Jonathan W.


    The three fundamental constitutive relations that describe fluid flow, strength, and deformation behavior of variably saturated soils are the soil-water retention curve (SWRC), hydraulic conductivity function (HCF), and suction-stress characteristic curve (SSCC). Until recently, the interrelations among the SWRC, HCF, and SSCC have not been well established. This work sought experimental confirmation of interrelations among these three constitutive functions. Results taken from the literature for six soils and those obtained for 11 different soils were used. Using newly established analytical relations among the SWRC, HCF, and SSCC and these test results, the authors showed that these three constitutive relations can be defined by a common set of hydromechanical parameters. The coefficient of determination for air-entry pressures determined independently using hydraulic and mechanical methods is >0.99, >0.98 for the pore size parameter, and 0.94 for the residual degree of saturation. One practical implication is that one of any of the four experiments (axis-translation, hydraulic, shear-strength, or deformation) is sufficient to quantify all three constitutive relations.

  14. Head First Statistics

    Griffiths, Dawn


    Wouldn't it be great if there were a statistics book that made histograms, probability distributions, and chi square analysis more enjoyable than going to the dentist? Head First Statistics brings this typically dry subject to life, teaching you everything you want and need to know about statistics through engaging, interactive, and thought-provoking material, full of puzzles, stories, quizzes, visual aids, and real-world examples. Whether you're a student, a professional, or just curious about statistical analysis, Head First's brain-friendly formula helps you get a firm grasp of statistics

  15. Head first Ajax

    Riordan, Rebecca M


    Ajax is no longer an experimental approach to website development, but the key to building browser-based applications that form the cornerstone of Web 2.0. Head First Ajax gives you an up-to-date perspective that lets you see exactly what you can do -- and has been done -- with Ajax. With it, you get a highly practical, in-depth, and mature view of what is now a mature development approach. Using the unique and highly effective visual format that has turned Head First titles into runaway bestsellers, this book offers a big picture overview to introduce Ajax, and then explores the use of ind

  16. Rocket injector head

    Green, C. W., Jr. (Inventor)


    A high number of liquid oxygen and gaseous hydrogen orifices per unit area are provided in an injector head designed to give intimate mixing and more thorough combustion. The injector head comprises a main body portion, a cooperating plate member as a flow chamber for one propellant, a cooperating manifold portion for the second propellant, and an annular end plate for enclosing an annular propellant groove formed around the outer edge of the body. All the openings for one propellant are located at the same angle with respect to a radial plane to permit a short combustion chamber.

  17. Strength of Plastics,

    evaluating the strength of structural elements is examined. The book is intended for design engineers, factory laboratory personnel, scientific research workers, and the design institutes. (Author-PL)

  18. Measurement of residual CO2 saturation at a geological storage site using hydraulic tests

    Rötting, T. S.; Martinez-Landa, L.; Carrera, J.; Russian, A.; Dentz, M.; Cubillo, B.


    Estimating long term capillary trapping of CO2 in aquifers remains a key challenge for CO2 storage. Zhang et al. (2011) proposed a combination of thermal, tracer, and hydraulic experiments to estimate the amount of CO2 trapped in the formation after a CO2 push and pull test. Of these three types of experiments, hydraulic tests are the simplest to perform and possibly the most informative. However, their potential has not yet been fully exploited. Here, a methodology is presented to interpret these tests and analyze which parameters can be estimated. Numerical and analytical solutions are used to simulate a continuous injection in a porous medium where residual CO2 has caused a reduction in hydraulic conductivity and an increase in storativity over a finite thickness (a few meters) skin around the injection well. The model results are interpreted using conventional pressure build-up and diagnostic plots (a plot of the drawdown s and the logarithmic derivative d s / d ln t of the drawdown as a function of time). The methodology is applied using the hydraulic parameters estimated for the Hontomin site (Northern Spain) where a Technology Demonstration Plant (TDP) for geological CO2 storage is planned to be set up. The reduction of hydraulic conductivity causes an increase in observed drawdowns, the increased storativity in the CO2 zone causes a delay in the drawdown curve with respect to the reference curve measured before CO2 injection. The duration (characteristic time) of these effects can be used to estimate the radius of the CO2 zone. The effects of reduced permeability and increased storativity are well separated from wellbore storage and natural formation responses, even if the CO2-brine interface is inclined (i.e. the CO2 forms a cone around the well). We find that both skin hydraulic conductivity and storativity (and thus residual CO2 saturation) can be obtained from the water injection test provided that water flow rate is carefully controlled and head build

  19. Strength Training and Your Child

    ... Feeding Your 1- to 2-Year-Old Strength Training and Your Child KidsHealth > For Parents > Strength Training ... prevent injuries and speed up recovery. About Strength Training Strength training is the practice of using free ...

  20. Mechatronic Hydraulic Drive with Regulator, Based on Artificial Neural Network

    Burennikov, Y.; Kozlov, L.; Pyliavets, V.; Piontkevych, O.


    Mechatronic hydraulic drives, based on variable pump, proportional hydraulics and controllers find wide application in technological machines and testing equipment. Mechatronic hydraulic drives provide necessary parameters of actuating elements motion with the possibility of their correction in case of external loads change. This enables to improve the quality of working operations, increase the capacity of machines. The scheme of mechatronic hydraulic drive, based on the pump, hydraulic cylinder, proportional valve with electrohydraulic control and programmable controller is suggested. Algorithm for the control of mechatronic hydraulic drive to provide necessary pressure change law in hydraulic cylinder is developed. For the realization of control algorithm in the controller artificial neural networks are used. Mathematical model of mechatronic hydraulic drive, enabling to create the training base for adjustment of artificial neural networks of the regulator is developed.

  1. DCS Hydraulics Submittal, Valencia County, New Mexico, USA

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  2. Chapter 12. Pure Tap Water Hydraulic Systems and Applications

    Conrad, Finn; Adelstorp, Anders


    Presentation of developed a modern pure tap water hydraulic components (Nessie), systems and industrial applications.......Presentation of developed a modern pure tap water hydraulic components (Nessie), systems and industrial applications....

  3. A tensor approach to the estimation of hydraulic conductivities in ...


    Jul 3, 2006 ... The HC values computed from the data measured on the weathered or ... Keywords: hydraulic conductivity tensor, roughness, combined stress, hydraulic aperture, Table Mountain ... the anisotropic nature of studied media.

  4. Effects of radial diffuser hydraulic design on a double-suction centrifugal pump

    Hou, H. C.; Zhang, Y. X.; Xu, C.; Zhang, J. Y.; Li, Z. L.


    In order to study effects of radial diffuser on hydraulic performance of crude oil pump, the steady CFD numerical method is applied and one large double-suction oil pump running in long-distance pipeline is considered. The research focuses on analysing the influence of its diffuser vane profile on hydraulic performance of oil pump. The four different types of cylindrical vane have been designed by in-house codes mainly including double arcs (DA), triple arcs (TA), equiangular spiral line (ES) and linear variable angle spiral line (LVS). During design process diffuser vane angles at inlet and outlet are tentatively given within a certain range and then the wrapping angle of the four types of diffuser vanes can be calculated automatically. Under the given inlet and outlet angles, the linear variable angle spiral line profile has the biggest wrapping angle and profile length which is good to delay channel diffusion but bring more friction hydraulic loss. Finally the vane camber line is thickened at the certain uniform thickness distribution and the 3D diffuser models are generated. The whole flow passage of oil pump with different types of diffusers under various flow rate conditions are numerically simulated based on RNG k-ɛ turbulent model and SIMPLEC algorithm. The numerical results show that different types of diffusers can bring about great difference on the hydraulic performance of oil pump, of which the ES profile diffuser with its proper setting angle shows the best hydraulic performance and its inner flow field is improved obviously. Compared with the head data from model sample, all designed diffusers can make a certain improvement on head characteristic. At the large flow rate conditions the hydraulic efficiency increases obviously and the best efficiency point shift to the large flow rate range. The ES profile diffuser embodies the better advantages on pump performance which can be explained theoretically that the diffuser actually acts as a diffusion

  5. Groundwater Flow and Thermal Modeling to Support a Preferred Conceptual Model for the Large Hydraulic Gradient North of Yucca Mountain

    McGraw, D.; Oberlander, P.


    The purpose of this study is to report on the results of a preliminary modeling framework to investigate the causes of the large hydraulic gradient north of Yucca Mountain. This study builds on the Saturated Zone Site-Scale Flow and Transport Model (referenced herein as the Site-scale model (Zyvoloski, 2004a), which is a three-dimensional saturated zone model of the Yucca Mountain area. Groundwater flow was simulated under natural conditions. The model framework and grid design describe the geologic layering and the calibration parameters describe the hydrogeology. The Site-scale model is calibrated to hydraulic heads, fluid temperature, and groundwater flowpaths. One area of interest in the Site-scale model represents the large hydraulic gradient north of Yucca Mountain. Nearby water levels suggest over 200 meters of hydraulic head difference in less than 1,000 meters horizontal distance. Given the geologic conceptual models defined by various hydrogeologic reports (Faunt, 2000, 2001; Zyvoloski, 2004b), no definitive explanation has been found for the cause of the large hydraulic gradient. Luckey et al. (1996) presents several possible explanations for the large hydraulic gradient as provided below: The gradient is simply the result of flow through the upper volcanic confining unit, which is nearly 300 meters thick near the large gradient. The gradient represents a semi-perched system in which flow in the upper and lower aquifers is predominantly horizontal, whereas flow in the upper confining unit would be predominantly vertical. The gradient represents a drain down a buried fault from the volcanic aquifers to the lower Carbonate Aquifer. The gradient represents a spillway in which a fault marks the effective northern limit of the lower volcanic aquifer. The large gradient results from the presence at depth of the Eleana Formation, a part of the Paleozoic upper confining unit, which overlies the lower Carbonate Aquifer in much of the Death Valley region. The

  6. The use of asphalt in hydraulic engineering

    Van de Velde, P.A.; Ebbens, E.H.; Van Herpen, J.A.


    Asphalt products have been used in the Netherlands in hydraulic engineering for a long time on a large scale, especially after the great disaster in 1953 when a large part of western Holland was flooded by the sea. After the disaster a great number of dikes had to be repaired very quickly and this w

  7. Elevator and hydraulics; Elevator to yuatsu

    Nakamura, I. [Hitachi, Ltd., Tokyo (Japan)


    A hydraulic type elevator is installed in relatively lower buildings as compared with a rope type elevator, but the ratio in the number of installation of the former elevator is increasing. This paper explains from its construction and features to especially various control systems for the riding comfort and safety. A direct push-up system with hydraulic jacks arranged beneath a car, and an indirect push-up system that has hydraulic jacks arranged on flank of a car and transmits the movement of a plunger via a rope are available. The latter system eliminates the need of large holes to embed hydraulic jacks. While the speed is controlled by controlling flow rates of high-pressure oil, the speed, position, acceleration and even time differential calculus of the acceleration must be controlled severely. The system uses two-step control for the through-speed and the landing speed. Different systems that have been realized may include compensation for temperatures in flow rate control valves, load pressures, and oil viscosity, from learning control to fuzzy control for psychological effects, or control of inverters in motors. 13 refs., 12 figs., 1 tab.

  8. Hydraulic adjustment of Scots pine across Europe

    Martínez-Vilalta, J.; Cochard, H.; Mencuccini, M.; Sterck, F.J.; Herrero, A.; Korhonen, J.F.J.; Llorens, P.; Nikinmaa, E.; Nolè, A.; Poyatos, R.; Ripullone, F.; Sass-Klaassen, U.; Zweifel, R.


    The variability of branch-level hydraulic properties was assessed across 12 Scots pine populations covering a wide range of environmental conditions, including some of the southernmost populations of the species. The aims were to relate this variability to differences in climate, and to study the po

  9. Influence of tray hydraulics on tray column

    Betlem, Bernardus H.L.; Rijnsdorp, J.E.; Rijnsdorp, J.E.; Azink, R.F.


    To column control, in contrast to column design, tray hold-up and dependencies of tray hold-up on the operating conditions play an important role. The essence of this article is the development of an improved model of tray hydraulics over a broad operating range and its experimental validation by

  10. Design of a hydraulic bending machine

    Steven G. Hankel; Marshall Begel


    To keep pace with customer demands while phasing out old and unserviceable test equipment, the staff of the Engineering Mechanics Laboratory (EML) at the USDA Forest Service, Forest Products Laboratory, designed and assembled a hydraulic bending test machine. The EML built this machine to test dimension lumber, nominal 2 in. thick and up to 12 in. deep, at spans up to...

  11. Sustainable hydraulic engineering through building with nature

    Vriend, de H.J.; Koningsveld, van M.; Aarninkhof, S.G.J.; Vries, de M.B.; Baptist, M.J.


    Hydraulic engineering infrastructures are of concern to many people and are likely to interfere with the environment. Moreover, they are supposed to keep on functioning for many years. In times of rapid societal and environmental change this implies that sustainability and adaptability are important

  12. The use of asphalt in hydraulic engineering

    Van de Velde, P.A.; Ebbens, E.H.; Van Herpen, J.A.


    Asphalt products have been used in the Netherlands in hydraulic engineering for a long time on a large scale, especially after the great disaster in 1953 when a large part of western Holland was flooded by the sea. After the disaster a great number of dikes had to be repaired very quickly and this w

  13. International Institute for Hydraulic and Environmental Engineering

    Mostertman, L. J.


    Describes the activities of the International Institute for Hydraulic and Environmental Engineering (IHE), whose primary function is the promotion of the better use of water resources as a vehicle of development by the transfer of knowledge and experience. (Author/RK)

  14. Digital hydraulic valving system. [design and development


    The design and development are reported of a digital hydraulic valving system that would accept direct digital inputs. Topics include: summary of contractual accomplishments, design and function description, valve parameters and calculations, conclusions, and recommendations. The electrical control circuit operating procedure is outlined in an appendix.

  15. Sustainable hydraulic engineering through building with nature

    Vriend, de H.J.; Koningsveld, van M.; Aarninkhof, S.G.J.; Vries, de M.B.; Baptist, M.J.


    Hydraulic engineering infrastructures are of concern to many people and are likely to interfere with the environment. Moreover, they are supposed to keep on functioning for many years. In times of rapid societal and environmental change this implies that sustainability and adaptability are important

  16. Reactive barriers: hydraulic performance and design enhancements.

    Painter, B D M


    The remediation of contaminated ground water is a multibillion-dollar global industry. Permeable reactive barriers (PRBs) are one of the leading technologies being developed in the search for alternatives to the pump-and-treat method. Improving the hydraulic performance of these PRBs is an important part of maximizing their potential to the industry. Optimization of the hydraulic performance of a PRB can be defined in terms of finding the balance between capture, residence time, and PRB longevity that produces a minimum-cost acceptable design. Three-dimensional particle tracking was used to estimate capture zone and residence time distributions. Volumetric flow analysis was used for estimation of flow distribution across a PRB and in the identification of flow regimes that may affect the permeability or reactivity of portions of the PRB over time. Capture zone measurements extended below the base of partially penetrating PRBs and were measured upgradient from the portion of aquifer influenced by PRB emplacement. Hydraulic performance analysis of standard PRB designs confirmed previously presented research that identified the potential for significant variation in residence time and capture zone. These variations can result in the need to oversize the PRB to ensure that downgradient contaminant concentrations do not exceed imposed standards. The most useful PRB design enhancements for controlling residence time and capture variation were found to be customized downgradient gate faces, velocity equalization walls, deeper emplacement of the funnel than the gate, and careful manipulation of the hydraulic conductivity ratio between the gate and the aquifer.



    Newton's general similarity criterion was applied to the distorted model. The results for the similarities of gravity force, drag force and pressure force are identical with those derived from relevant differential equations of fluid flow. And the selected limits of the distorted ratio were studied and the simulation of roughness coefficient of distorted model was conducted by means of hydraulic test.

  18. Separation and pattern formation in hydraulic jumps

    Bohr, Tomas; Ellegaard, C.; Hansen, A. Espe;


    We present theory and experiments on the circular hydraulic jump in the stationary regime. The theory can handle the situation in which the fluid flows over an edge far away from the jump. In the experiments the external height is controlled, and a series of transitions in the flow structure appe...


    The hydraulic conductivity of three 2.9 m2 (32 sq ft) geosynthetic clay liners (GCLs) was measured. Tests were performed on individual sheets of the GCLs, on overlapped pieces of GCLs, and on composite liners consisting of a punctured geomembrane overlying a GCL. Hyd...

  20. Towards Autonomous Control of Hydraulic Actuator Systems

    Hansen, Poul Erik; Conrad, Finn


    Presentation of new developed control algorithms to increase autonomy and intelligence of hydraulic control systems. A refinement of relaytuning method is used to determine the control parameters of a lag/lead controller and a poleplacement controller. Further, a fail-safe function is developed t...

  1. Power management in hydraulically actuated mobile equipment

    Pedersen, Henrik Clemmensen; Andersen, Torben Ole; Hansen, Michael Rygaard


    The focus of the current paper is on the control of hydraulic systems when utilizing the advances that electronic control may bring with regard to power management, prioritized flow sharing and anti-stall, arising from being able to control both pump, valves and engine electronically. A simple mo...

  2. Dentin permeability: determinants of hydraulic conductance.

    Reeder, O W; Walton, R E; Livingston, M J; Pashley, D H


    A technique is described which permits measurements of the ease with which fluid permeates dentin. This value, the hydraulic conductance of dentin, increased as surface area increases and/or as dentin thickness decreases. It increased 32-fold when dentin was acid etched due to removal of surface debris occluding the tubules.

  3. Analysis of Innovative Design of Energy Efficient Hydraulic Actuators

    M Osman Abdalla


    Hydraulic cylinder actuators are used extensively in industrial, construction and agricultural works. The small sized outlet ports of the cylinders resist the flow of discharged oil; and as a result the piston motion is slowed down. This causes a lot of heat generation and energy loss within the actuators. The study investigates and analyzes the possibilities of reducing the hydraulic resistance and increasing efficiency of the hydraulic actuator. Conventional hydraulic cylinders are simulate...


    Jiahua FAN


    Traveling and stationary internal hydraulic jumps in density currents with positive or negative entrainment coefficients were analyzed based on simple assumptions. An expression of internal hydraulic jumps with entrainment coefficients was derived. Experimental data, published in literature, of stationary internal hydraulic jumps in turbid, thermal and saline density currents including measured values of water entrainment were used to compare with theory. Comparison was also made of traveling internal hydraulic jumps between measured data and theory.

  5. Heading in soccer: dangerous play?

    Spiotta, Alejandro M; Bartsch, Adam J; Benzel, Edward C


    Soccer is the world's most popular sport and unique in that players use their unprotected heads to intentionally deflect, stop, or redirect the ball for both offensive and defensive strategies. Headed balls travel at high velocity pre- and postimpact. Players, coaches, parents, and physicians are justifiably concerned with soccer heading injury risk. Furthermore, risk of long-term neurocognitive and motor deficits caused by repetitively heading a soccer ball remains unknown. We review the theoretical concerns, the results of biomechanical laboratory experiments, and the available clinical data regarding the effects of chronic, subconcussive head injury during heading in soccer.



    A method of the optimal hydraulic design and CAD application of runner blades of axial-flow hydraulic turbines are discussed on the basis of optimization principle and CAD technique in this paper. Based on the theory of fluid dynamics, the blade′s main geometrical parameter, working parameters and performances index of the blades and the relationship between them are analysed, and the mathematical model of optimal hydraulic design of axial-flow runners has been established. Through nonlinear programming, the problems can be solved. By making use of the calculation geometry and computer graphics, the distribution method of the singular points, and an CAD applied software, an optimal hydraulic design are presented.

  7. Hydraulic Bureaucracy in a Modern Hydraulic Society – Strategic Group Formation in the Mekong Delta, Vietnam

    Hans-Dieter Evers


    Among these strategic groups, the hydraulic bureaucracy and hydraulic construction business are the most crucial in terms of the specific role they play in the hydraulic landscape of the Mekong delta. Both groups exert considerable influence on water resources management and strive for the same resources, namely public funds (including Overseas Development Aid that is directed to hydraulic infrastructure development. This paper illustrates how both groups have emerged due to the growing need for water resources management in the delta and how they have set up alliances for mutually sharing resources in the long run. Furthermore, it is shown how both groups have adapted their resource-oriented strategies and actions to respond to the changes in the economic and political environment in Vietnam’s recent history.

  8. Computed Tomography (CT) -- Head

    Full Text Available ... are present in the paranasal sinuses. plan radiation therapy for cancer of the brain or other tissues. guide the ... Radiation Therapy for Brain Tumors Radiation Therapy for Head and Neck Cancer Others American Stroke Association National Stroke Association top ...

  9. Head space analysis

    Stekelenburg, G.J. van; Koorevaar, G.

    Additional analytical information is given about the method of head space analysis. From the data presented it can be concluded that this technique may be advantageous for enzyme kinetic studies in turbid solutions, provided a volatile organic substance is involved in the chemical reaction. Also

  10. Sculpting Ceramic Heads.

    Sapiro, Maurice


    Clay sculpture is difficult to produce because of the requirements of kiln firing. The problems can be overcome by modeling the original manikin head and making a plaster mold, pressing molding slabs of clay into the plaster mold to form the hollow clay armature, and sculpting on the armature. (IS)

  11. Lubricating the swordfish head

    Videler, John J.; Haydar, Deniz; Snoek, Roelant; Hoving, Henk-Jan T.; Szabo, Ben G.


    The swordfish is reputedly the fastest swimmer on Earth. The concave head and iconic sword are unique characteristics, but how they contribute to its speed is still unknown. Recent computed tomography scans revealed a poorly mineralised area near the base of the rostrum. Here we report, using magnet

  12. Prognosis in head injury.

    Jane, J A; Rimel, R W


    The prognosis of head injury when viewed from the perspective of the Glasgow Coma Scale confirms the utility of this measure. In particular, decrease in mortality is associated with an increase in GCS. In addition, the motor score portion of the GCS was of predictive value when taken alone. The outcome of patients in coma (GCS less than 8) was closely related to three preventable or treatable factors, namely, hypoxia, shock, and increased intracranial pressure. These three factors, when considered in combination, powerfully predicted mortality. Of considerable interest was the finding that moderate head injury (GCS 9-12) was associated with a small but perhaps preventable mortality. The morbidity was intermediate between that of severe and minor and was surprisingly high. Minor head injury, while not associated with significant mortality, also resulted in considerable morbidity. Neuropsychological evaluation of the patients and an experimental study suggests that an organic component may be involved even in this group. To deal with head injury, distinctions must be made between grades of severity. The Glasgow Coma Scale is suited for this task. Nonetheless, the recognition of this basic continuity should elicit the further recognition that different health providers may be involved in the case of, say, severe, as opposed to mild, injury, and that different outcome measures are suitable for one group but not another.

  13. Experiment on Hydraulic Fracturing in Rock and Induced Earthquake

    Yan Yuding; Li Yalin; Zhang Zhuan; Ouyang Lisheng; Xie Mingfu


    Experiment on rock hydraulic fracturing strength under different confining pressures was conducted on a series of test specimens with various pre-cracks prepared from 7 types of rock.Combining the data of an actual reservoir-induced earthquake with the experimental results of the contemporary tectonic stress field according to the theory of rock strength and the principle and method of rock fracture mechanics, the authors tentatively investigated the earthquakes induced by pore-water pressure in rock and obtained the initial results as follows: ( 1 ) One type of induced earthquake may occur in the case of larger tectonic stress on such weak planes that strike in similar orientation of principle tectonic compressional stress in the shallows of the rock mass; the pore-water pressure σp may generate tensile fracture on them and induce small earthquakes; (2) Two types of induced earthquake may occur in the case of larger tectonic stress, i.e., ① on such weakness planes that strike in similar orientation of principle tectonic compressioual stress, σ1, in the shallows of the rockmass, the pore-water pressure, σp, may generate tensile fracture on them and induce small earthquakes; ② When the tectonic stress approximates the shear strength of the fracture, the pore-water pressure σp may reduce the normal stress, σn, on the fracture face causing failure of the originally stable fracture,producing gliding fracture and thus inducing an earthquake. σp may also increase the fracture depth, leading to an induced earthquake with the magnitude larger than the previous potential magnitude; (3) There is a depth limit for each type of rock mass, and no induced earthquake will occur beyond this limit.

  14. Head injuries, heading, and the use of headgear in soccer.

    Niedfeldt, Mark W


    Soccer has more than 265 million players around the world and is the only contact sport with purposeful use of the head for controlling and advancing the ball. Head contact in soccer has the potential to cause acute traumatic brain injury including concussion or, potentially, a pattern of chronic brain injury. Although early retrospective research on the effects of soccer heading seemed to suggest that purposeful heading may contribute to long-term cognitive impairment, prospective controlled studies do not support this and, in fact, suggest that purposeful heading may not be a risk factor for cognitive impairment. Headgear has not been shown to be effective in reducing ball impact but may be helpful in reducing the force of non-ball-related impacts to the head. There are concerns that universal use of headgear may cause more aggressive heading and head challenges, leading to increased risk of injury.

  15. Strengths of Remarried Families.

    Knaub, Patricia Kain; And Others


    Focuses on remarried families' (N=80) perceptions of family strengths, marital satisfaction, and adjustment to the remarried situation. Results indicated that although most would like to make some changes, scores on the measurements used were high. A supportive environment was the most important predictor of family strength and success. (JAC)

  16. Building on Our Strengths.

    Hill, Robert


    Comments on the feeling that the American family is disintegrating, and that many criticisms traditionally made about Black families are now made about White families. Suggests that people need to stress family strengths. As an example, five major strengths of Black families are described: flexibility, work and achievement ethics, religiosity, and…

  17. Hydraulic power take-off for wave energy systems

    Christensen, Georg Kronborg


    Investigation and laboratory experiments with a hydraulic power conversion system for converting forces from a 2.5m diamter float to extract energy from seawaves. The test rig consists of a hydraulic wave simulator and a hydraulic point absorber. The absorber converts the incomming forces...

  18. 21 CFR 880.5110 - Hydraulic adjustable hospital bed.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydraulic adjustable hospital bed. 880.5110... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5110 Hydraulic adjustable hospital bed. (a) Identification. A hydraulic adjustable...

  19. 14 CFR 33.72 - Hydraulic actuating systems.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hydraulic actuating systems. 33.72 Section... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.72 Hydraulic actuating systems. Each hydraulic actuating system must function properly under all conditions in which...

  20. 7 CFR 2902.10 - Mobile equipment hydraulic fluids.


    ... Comprehensive Procurement Guideline, 40 CFR 247.11. ... 7 Agriculture 15 2010-01-01 2010-01-01 false Mobile equipment hydraulic fluids. 2902.10 Section... PROCUREMENT Designated Items § 2902.10 Mobile equipment hydraulic fluids. (a) Definition. Hydraulic...

  1. Comparison of four methods to assess hydraulic conductivity

    Benson, C.H. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering; Gunter, J.A. [Gunter (John A.), Round Rock, TX (United States); Boutwell, G.P. [STE, Inc., Baton Rouge, LA (United States); Trautwein, S.J. [Trautwein Soil Testing Equipment Co., Houston, TX (United States); Berzanskis, P.H. [Hoechst-Celanese, Inc., Pampa, TX (United States)


    A hydraulic conductivity assessment that was conducted on four test pads constructed to the same specifications with soil from the same source by four different contractors is described. The test pads had distinctly different field hydraulic conductivities, even though they were constructed with similar soil, to similar compaction conditions, and with similar machinery. Adequate hydration time was key in achieving low field hydraulic conductivity. More extensive processing was another factor responsible for low field hydraulic conductivity. Four different test methods were used to assess the hydraulic conductivity of each test pad: (1) sealed double-ring infiltrometers (SDRIs); (2) two-stage borehole permeameters; (3) laboratory hydraulic conductivity tests on large block specimens; and (4) laboratory hydraulic conductivity tests on small specimens collected in thin-wall sampling tubes. The tests were conducted independently by each of the writers. After the tests were completed, the results were submitted and compared. Analysis of the test results show that the three large-scale test methods generally yield similar hydraulic conductivities. For two of the test pads, however, the hydraulic conductivities of the specimens collected in sampling tubes were significantly lower than the field hydraulic conductivities. Both of these test pads had high field hydraulic conductivity. Thus, there is little value in using small specimens to assess field hydraulic conductivity.

  2. 23 CFR 650.111 - Location hydraulic studies.


    ... 23 Highways 1 2010-04-01 2010-04-01 false Location hydraulic studies. 650.111 Section 650.111 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains §...

  3. Study of heat treatment parameters for large-scale hydraulic steel gate track

    Ping-zhou CAO


    Full Text Available In order to enhance external hardness and strength, a large-scale hydraulic gate track should go through heat treatment. The current design method of hydraulic gate wheels and tracks is based on Hertz contact linear elastic theory, and does not take into account the changes in mechanical properties of materials caused by heat treatment. In this study, the heat treatment parameters were designed and analyzed according to the bearing mechanisms of the wheel and track. The quenching process of the track was simulated by the ANSYS program, and the temperature variation, residual stress, and deformation were obtained and analyzed. The metallurgical structure field after heat treatment was predicted by the method based on time-temperature-transformation (TTT curves. The results show that the analysis method and designed track heat treatment process are feasible, and can provide a reference for practical projects.

  4. Influence of Spacer Grid Outer Strap on Fuel Assembly Thermal Hydraulic Performance

    Jingwen Yan


    Full Text Available The outer strap as a typical structure of a spacer grid enhances the mechanical strength, decreases hang-up susceptibility, and also influences thermal hydraulic performance, for example, pressure loss, mixing performance, and flow distribution. In the present study, a typical grid spacer with different outer strap designs is adopted to investigate the influence of outer strap design on fuel assembly thermal hydraulic performance by using a commercial computational fluid dynamics (CFD code, ANSYS CFX, and a subchannel analysis code, FLICA. To simulate the outer straps’ influence between fuel assemblies downstream, four quarter-bundles from neighboring fuel assemblies are constructed to form the computational domain. The results show that the outer strap design has a major impact on cross-flow between fuel assemblies and temperature distribution within the fuel assembly.


    Lee, S.; Barnes, O.


    The hydraulic results demonstrate that pump head pressure of 20 psi recirculates about 5.6 liters/min flowrate through the existing 0.131-inch orifice when a valve connected to NT-41 is closed. In case of the valve open to NT-41, the solution flowrates to HB-Line tanks, NT-21 and NT-41, are found to be about 0.5 lpm and 5.2 lpm, respectively. The modeling calculations for the mixing operations of miscible fluids contained in the HB-Line tank NT-21 were performed by taking a three-dimensional Computational Fluid Dynamics (CFD) approach. The CFD modeling results were benchmarked against the literature results and the previous SRNL test results to validate the model. Final performance calculations were performed for the nominal case by using the validated model to quantify the mixing time for the HB-Line tank. The results demonstrate that when a pump recirculates a solution volume of 5.7 liters every minute out of the 72-liter tank contents containing two acid solutions of 2.7 M and 0 M concentrations (i.e., water), a minimum mixing time of 1.5 hours is adequate for the tank contents to get the tank contents adequately mixed. In addition, the sensitivity results for the tank contents of 8 M existing solution and 1.5 M incoming species show that the mixing time takes about 2 hours to get the solutions mixed.

  6. Hydraulic behaviour of the floating wave energy converter Wave Dragon



    The objective of the project is to establish a scale 1:4.5 test model of the floating offshore wave energy converter - Wave Dragon - for testing at 5 m water depth in the Inlet Nissum Bredning. The test model will be equipped with an existing diameter 340 mm model turbine plus additional outlet tubes simulating the resistance from 1 - 16 turbines. The model will be designed to stay afloat even with a total loss of air pressure in the open bottom buoyancy chambers. The test series will primarily focus on measurements of hydraulic response, forces in the mooring system and overtopping quantities. Also data such as head, rotational speed and power production from the turbine will be monitored during the whole test period. The project will verify the effect of the pressured air buoyancy system, which cannot be scaled correctly in laboratory scale models. The test results will allow for an evaluation of the Wave Dragon power production as a function of sea state and freeboard height, in order to calibrate the existing WD-power simulation software. The model can be utilized for further testing of turbine regulation and stress and strain in the structure, establishing the necessary knowledge base for deploying a full-scale demonstration plant. This CD-ROM contains various videos, reports, notes, conference papers and Power Point presentations on the making of the wave energy converter Wave Dragon. (BA)

  7. Effects of Head Size on the Performance of Twist-Off Bolts

    Schnupp, Keith Otto


    This study examines a specific application of button-head type twist-off bolts. Currently, the Research Council on Structural Connections Specification (2000) removes the requirement for ASTM F436 washers (ASTM 2000a) under the bolt head of twist-off bolts where the head diameter equals or exceeds that of an ASTM F436 washer when oversized and slotted holes are used. The need for washers is also removed for A490 strength bolts used on steels with specified yield strengths less than 40 ksi p...

  8. Internal hydraulic loss in a seal-less centrifugal Gyro pump.

    Makinouchi, K; Ohara, Y; Sakuma, I; Damm, G; Mizuguchi, K; Jikuya, T; Takatani, S; Noon, G P; Nosé, Y


    A new index "loss factor Z" defined by Eq. 1 was introduced as the absolute expression of the mock loop resistance for testing a nonpulsatile pump. [formula: see text] where gamma is specific gravity of the fluid, g is the acceleration of gravity, delta P is total pressure head, and Q is flow. Z is expected to be constant, regardless of the pumping parameters. Z values obtained in the same mock loop but with different rotary blood pumps were almost identical and were defined as Z0. New methods of analysis of the flow-restrictive conditions of various rotary blood pumps are proposed in this paper: namely, differential loss factor delta Z, and loss factor sensitivity delta Z/delta A. The proposed Z-Q curves demonstrated better performance mapping than the conventional delta P-Q curves. Delta Z is the difference between the Z-Q curves of two different pumps. A is a design parameter of the pump; therefore delta Z/delta A is a quantitative expression of the effect of the design change on the hydraulic performance. These various indices were used to analyze the internal hydraulic loss of a centrifugal pump (Gyro pump). The relationship between its gap size (rotor casing) and hydraulic performance was assessed quantitatively by these indices. In this paper, the derivation processes and above-mentioned indices are described.

  9. Application of Large-Scale Inversion Algorithms to Hydraulic Tomography in an Alluvial Aquifer.

    Fischer, P; Jardani, A; Soueid Ahmed, A; Abbas, M; Wang, X; Jourde, H; Lecoq, N


    Large-scale inversion methods have been recently developed and permitted now to considerably reduce the computation time and memory needed for inversions of models with a large amount of parameters and data. In this work, we have applied a deterministic geostatistical inversion algorithm to a hydraulic tomography investigation conducted in an experimental field site situated within an alluvial aquifer in Southern France. This application aims to achieve a 2-D large-scale modeling of the spatial transmissivity distribution of the site. The inversion algorithm uses a quasi-Newton iterative process based on a Bayesian approach. We compared the results obtained by using three different methodologies for sensitivity analysis: an adjoint-state method, a finite-difference method, and a principal component geostatistical approach (PCGA). The PCGA is a large-scale adapted method which was developed for inversions with a large number of parameters by using an approximation of the covariance matrix, and by avoiding the calculation of the full Jacobian sensitivity matrix. We reconstructed high-resolution transmissivity fields (composed of up to 25,600 cells) which generated good correlations between the measured and computed hydraulic heads. In particular, we show that, by combining the PCGA inversion method and the hydraulic tomography method, we are able to substantially reduce the computation time of the inversions, while still producing high-quality inversion results as those obtained from the other sensitivity analysis methodologies.

  10. HydrogeoEstimatorXL: an Excel-based tool for estimating hydraulic gradient magnitude and direction

    Devlin, J. F.; Schillig, P. C.


    HydrogeoEstimatorXL is a free software tool for the interpretation of flow systems based on spatial hydrogeological field data from multi-well networks. It runs on the familiar Excel spreadsheet platform. The program accepts well location coordinates and hydraulic head data, and returns an analysis of the area flow system in two dimensions based on (1) a single best fit plane of the potentiometric surface and (2) three-point estimators, i.e., well triplets assumed to bound planar sections of the potentiometric surface. The software produces graphical outputs including histograms of hydraulic gradient magnitude and direction, groundwater velocity (based on a site average hydraulic properties), as well as mapped renditions of the estimator triangles and the velocity vectors associated with them. Within the software, a transect can be defined and the mass discharge of a groundwater contaminant crossing the transect can be estimated. This kind of analysis is helpful in gaining an overview of a site's hydrogeology, for problem definition, and as a review tool to check the reasonableness of other independent calculations.

  11. Results of hydraulic tests in wells DOE-1, 2, 3, Salt Valley, Grand County, Utah

    Rush, F. Eugene; Hart, I.M.; Whitfield, M.S.; Giles, T.F.; D'Epagnier, T. E.


    Three exploratory wells were drilled for geological, geophysical, and hydrological purposes in Salt Valley, Grand County, Utah. Cap rock, salt, and interbeds of the Paradox Member of the Hermosa Formation of Middle Pennsylvanian age were penetrated. The observed depth below land surface of the cap rock-salt interface ranges from 163 meters (m) to 191 meters. Approximately the upper 100 meters of cap rock were unsaturated by ground water. Within the saturated part of the cap rock, hydraulic heads generally decrease with depth and southwestward. Ion concentrations generally increase with depth in the saturated cap rock.Hydraulic conductivity of cap rock, as determined from pumping tests, may be on the order of 5 x 10-3 meters per day; as a result, ground-water flow rates in the cap rock are probably very low. A carbon 14 specific activity for cap rock water yielded an uncorrected "age" of greater than 36,000 years. Salt and interbeds have hydraulic conductivities probably less than 1 x 10-4 meters per day.

  12. Experiences with the hydraulic design of the high specific speed Francis turbine

    Obrovsky, J.; Zouhar, J.


    The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of ČKD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between ns=425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper.

  13. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain ...

  14. Head Lice: Prevention and Control

    ... Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Prevention & Control Language: English Español (Spanish) Recommend on Facebook Tweet ... that can be taken to help prevent and control the spread of head lice: Avoid head-to- ...

  15. Head and Neck Cancer Treatment

    ... Professions Site Index A-Z Head and Neck Cancer Treatment Head and neck cancer overview What are my ... and neck cancer. For updated information on new cancer treatments that are available, you should discuss these issues ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... to remain perfectly still and follow breath-holding instructions while the images are being recorded. If you ... Images related to Magnetic Resonance Imaging (MRI) - Head Videos related to Magnetic Resonance Imaging (MRI) - Head Sponsored ...

  17. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... the limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) ... ray, CT and ultrasound. top of page How is the procedure performed? MRI examinations may be performed ...

  18. Head and Neck Cancer Treatment

    ... oncologist will listen to the history of your problem and perform a physical examination. Consultations with other members of the head and neck team, such as the head and neck surgeon, pathologist, ...

  19. Sports-related Head Injury

    ... difficulty expressing words or thoughts; dysarthric speech Head Injury Prevention Tips Buy and use helmets or protective head gear approved by the ASTM for specific sports 100 percent of the time. The ASTM has ...

  20. Preventing head injuries in children

    Concussion - preventing in children; Traumatic brain injury - preventing in children; TBI - children; Safety - preventing head injury ... Helmets help to prevent head injuries. Your child should wear a ... sports or activities: Playing contact sports, such as lacrosse, ...

  1. Role of loading on head stability and effective neck stiffness and viscosity.

    Simoneau, Martin; Denninger, Marc; Hain, Timothy C


    This experiment tests the hypothesis that loading the head would increase head stability. In particular, we hypothesized that an arrangement of the head so that muscle activation is required to counteract a load would significantly increase effective neck stiffness and viscosity, which would be associated with lower peak head angular velocity following abrupt force perturbations applied to the head. Seven young healthy subjects had their head loaded (preload) using a weight/pulley apparatus. Then, the head was pulled either forward or backward by dropping an additional weight onto the preload, causing an impulse of force followed by an increase in load. We recorded the applied force and head angular velocity. Neck viscoelastic properties as a function of loading were estimated by fitting experimental data to a second-order mathematical model of the head biomechanics. Across preloads varying from 2.22 to 8.89 N, peak head angular velocity decreased by 18.2% for the backward and by 19.9% for forward perturbations. As preload increased, simulated effective neck stiffness and viscosity significantly increased leading to lower peak angular velocity. These results demonstrated that loading reduces peak head angular velocity and that change in muscle stiffness and viscosity is a feasible explanation for this effect. We propose that reduction in peak head velocity could be caused by modulation of the strength of the vestibulo-collic reflex.

  2. Effects of simultaneous training for strength and endurance on upper and lower body strength and running performance.

    Hortobágyi, T; Katch, F I; Lachance, P F


    This study examined simultaneous training for strength and endurance during a 13-week, 3-day a week program of hydraulic resistive circuit training and running. Eighteen college males (U.S. Army ROTC) were placed into low resistance (LR; n = 10) or high resistance (HR; n = 8) groups, and 10 college males were controls and did not train. There were 20 exercise stations (7 upper and lower body, and 6 supplementary). LR and HR performed 2 circuits with a work/rest ratio of 20 to 40 s during the 40 min workout. LR trained at two low resistances (approximately 100 cm.s-1), while HR trained at a higher resistance (approximately 50 cm.s-1). Following the workout, subjects ran 2 miles. Pre and post tests included strength, physical fitness, and anthropometry. Strength was assessed with (1) hydraulic resistance dynamometry for 4 exercises at 2 speeds using a computerized dynamometer (Hydra-Fitness, Belton, TX); (2) isokinetic and isotonic upright squat and supine bench press using the Ariel Exerciser (Trabuco Canyon, CA); (3) concentric and eccentric arm flexion/extension at 60 and 120 degrees.s-1 on the Biodex dynamometer (Shirley, NY), and (4) 1-RM free weight concentric and eccentric arm flexion and extension. The fitness tests included 2-mile run, sit-ups, and push-ups. Anthropometry included 3 fatfolds, 6 girths, and arm and leg volume. There were no significant changes in body composition or interactions between the fitness test measures and the 2 training groups (p greater than 0.05). Improvements averaged 15% (run time), 30% (push-ups), and 19% (sit-ups; p less than 0.05). Significant improvements also occurred in 3 of 8 measures for hydraulic testing (overall change 8.8%), in 3 of 4 1-RM tests (9.4%), and in 2 of 8 Biodex tests (6%), but no significant changes for isokinetic and isotonic squat and bench press (1.9%). The change in overall strength averaged 6.5% compared to 16% in a prior study that used hydraulic resistive training without concomitant running. We

  3. The puzzle of high heads beneath the West Cumbrian coast, UK: a possible solution

    Black, John H.; Barker, John A.


    A region of high heads within the Borrowdale Volcanic Group (BVG; a fractured crystalline rock) beneath the coastal plain of West Cumbria, England (UK), is identified as a possible relic left over by the Late Devensian ice sheet. It was found during investigations in the 1990s. Contemporary modelling work failed to produce a satisfactory explanation of the high heads compatible with the `cold recharge' isotopic signature of the groundwater. This study has reassessed the original hydraulic testing results. By plotting density-adjusted heads versus their depth below the water table in the immediate vicinity of the borehole in which they were measured, a depth profile resembling a `wave' was revealed with a peak value located at 1,100 m depth. The possibility that this wave represents relic heads from the last major ice sheet has been assessed using one-dimensional mathematical analysis based on a poroelastic approach. It is found that a wet-based ice sheet above the West Cumbrian coast was probably thick enough and sufficiently long-lasting to leave such relic heads providing that the hydraulic diffusivity of the BVG is in the order of 10-6 m s-1. Initial assessment 20 years ago of the long-interval slug tests suggested that such low values are not likely. More recent interpretation argues for such low values of hydraulic diffusivity. It is concluded that ice sheet recharge is the most likely cause of the raised heads, that the BVG contains significant patches of very low conductivity rock, and that long-interval single-hole tests should be avoided in fractured crystalline rock.

  4. Joint assimilation of piezometric heads and groundwater temperatures for improved modelling of river-aquifer interactions

    Kurtz, Wolfgang; Hendricks-Franssen, Harrie-Jan; Vereecken, Harry


    Measured groundwater temperatures close to streams contain valuable information for the assessment of mass transfer rates between river and aquifer and the hydraulic properties around a streambed. For groundwater management close to rivers, the characterization of these hydraulic properties is of special interest because exchange fluxes between river and aquifer influence the sustainability of groundwater abstraction and the quality of pumped drinking water. Additionally, it can be important for groundwater management to gain reliable predictions of groundwater temperatures, e.g. in order to regulate the temperature of extracted drinking water. Data assimilation techniques, like the ensemble Kalman filter (EnKF), provide a flexible stochastic framework to merge model simulations with different types of measurement data in order to enhance the (real-time) prediction of groundwater states and to improve the estimation of uncertain hydraulic subsurface parameters. EnKF has already been used for managed river-aquifer systems to improve the prediction of groundwater levels and the estimation of hydraulic parameters by the assimilation of measured piezometric head data. As temperature data can provide additional information on stream-aquifer exchange it is investigated whether this information further constrains states, fluxes and parameters of the river-groundwater system. For this purpose, we performed data assimilation experiments with two different model setups: (i) a simple synthetic model of a river-aquifer system where the parameters and simulation conditions were perfectly known (ii) a more complex model of the Limmat aquifer in Zurich where real-world data were assimilated. Results for the synthetic case suggest that a joint assimilation of piezometric heads and groundwater temperatures together with updating of uncertain hydraulic conductivities and leakage coefficients gives the best estimation of states, fluxes and hydraulic properties (i.e., hydraulic

  5. Short and long-term strength of shale rocks

    Rybacki, Erik; Dresen, Georg


    Stimulation of oil and gas bearing shales commonly utilizes advanced hydraulic fracturing techniques to enhance the production rate. Successful hydrofrac campaigns depend on the geomechanical properties of the reservoir. For example, the short term strength and brittleness may control the hydraulic breakdown pressure and borehole stability. The long term creep properties may determine the closure rate of hydraulically induced fractures, for example by proppant embedment. We performed a series of mechanical tests on shales with different mineral content, porosity and maturity. Cylindrical samples of 1-5 cm in diameter and 2-10 cm in length were deformed at confining pressures of 0.1 - 400 MPa and temperatures of 25°-400°C in constant strain rate and constant stress mode in order to evaluate the influence of loading conditions and composition on their strength and ductility. Short-term constant strain rate tests show that, at fixed loading direction with respect to bedding orientation, the peak strength and Young's modulus vary with mineral content, humidity and porosity, but depend also on applied pressure, temperature and strain rate. The (porosity-corrected) variation of peak strength and Young's modulus with composition can be roughly estimated from the mechanical behavior of all components at given pressure-temperature conditions and their volumetric proportion. Samples deforming in the brittle-semibrittle regime may be characterized by empirical brittleness indices based on their deformation behavior, Young's modulus, or bulk composition. These indices are correlated at low pressure-temperature conditions (corresponding to long-term deformation experiments at constant load show transient viscoplastic creep behavior. The associated strain rates increase with increasing differential stress, increasing temperature and decreasing pressure, accompanied by slight porosity reduction. Therefore, estimates of fracture healing rates by proppant embedment require to

  6. Assimilation of temperature and hydraulic gradients for quantifying the spatial variability of streambed hydraulics

    Huang, Xiang; Andrews, Charles B.; Liu, Jie; Yao, Yingying; Liu, Chuankun; Tyler, Scott W.; Selker, John S.; Zheng, Chunmiao


    Understanding the spatial and temporal characteristics of water flux into or out of shallow aquifers is imperative for water resources management and eco-environmental conservation. In this study, the spatial variability in the vertical specific fluxes and hydraulic conductivities in a streambed were evaluated by integrating distributed temperature sensing (DTS) data and vertical hydraulic gradients into an ensemble Kalman filter (EnKF) and smoother (EnKS) and an empirical thermal-mixing model. The formulation of the EnKF/EnKS assimilation scheme is based on a discretized 1D advection-conduction equation of heat transfer in the streambed. We first systematically tested a synthetic case and performed quantitative and statistical analyses to evaluate the performance of the assimilation schemes. Then a real-world case was evaluated to calculate assimilated specific flux. An initial estimate of the spatial distributions of the vertical hydraulic gradients was obtained from an empirical thermal-mixing model under steady-state conditions using a constant vertical hydraulic conductivity. Then, this initial estimate was updated by repeatedly dividing the assimilated specific flux by estimates of the vertical hydraulic gradients to obtain a refined spatial distribution of vertical hydraulic gradients and vertical hydraulic conductivities. Our results indicate that optimal parameters can be derived with fewer iterations but greater simulation effort using the EnKS compared with the EnKF. For the field application in a stream segment of the Heihe River Basin in northwest China, the average vertical hydraulic conductivities in the streambed varied over three orders of magnitude (5 × 10-1 to 5 × 102 m/d). The specific fluxes ranged from near zero (qz < ±0.05 m/d) to ±1.0 m/d, while the vertical hydraulic gradients were within the range of -0.2 to 0.15 m/m. The highest and most variable fluxes occurred adjacent to a debris-dam and bridge pier. This phenomenon is very likely

  7. Soil water balance in an unsaturated pyroclastic slope for evaluation of soil hydraulic behaviour and boundary conditions

    Pirone, Marianna; Papa, Raffaele; Nicotera, Marco Valerio; Urciuoli, Gianfranco


    Flowslides in granular soils pose a major threat to life and the environment. Their initiation in unsaturated soils is regulated by rainfall infiltration which reduces the matric suction and hence shear strength. Analysis of such phenomena is of strategic importance especially when it aims to mitigate landslide risk by means of early warning systems (EWSs). In this framework, physically-based models need to reproduce the hydro-mechanical behaviour of the slopes through numerical analyses, whose main uncertainty concerns the hydraulic conditions at the boundaries of the studied domain and hydraulic conductivity functions of unsaturated soils. Hence consummate knowledge of both these factors is absolutely necessary for efficient predictions. In this paper hydraulic boundary conditions and hydraulic conductivity functions are investigated at the scale of the slope through an application of soil water balance based on in-situ monitoring at the test site of Monteforte Irpino (southern Italy). Meteorological data, matric suction and soil water content measurements were collected over four years at the test site. The soil water balance was analysed on a seasonal time scale with regard to the whole pyroclastic cover resting on the steep limestone substratum. Infiltration and runoff are estimated, interaction between the soil cover and the substratum is investigated, and the hydraulic conductivity functions operative at the site scale are defined.

  8. Simulating the Effects of Structural Parameters on the Hydraulic Performances of Venturi Tube

    Yanqi Sun


    Full Text Available The effects of Venturi structural parameters on its hydraulic performance were studied, which provided theoretical basis for the design of Venturi injector. With an inlet diameter of 50 mm, based on the method of computational fluid dynamics (CFD, the effects of the structural parameters (such as throat taper, throat contraction ratio, and throat length on their hydraulic performance (such as outlet faceted average velocity, minimum pressure, and critical pressure were studied under different inlet pressures and pressure differences between inlet and outlet. A power function relationship existed between the mean velocity in outlet section and pressure difference, with an approximate flow stance index of 0.53. Minimum pressure occurred in the throat inlet wall and there was a linear relationship between the minimum pressure and the pressure difference at the inlet and outlet. The throat contraction ratio was the main factor on the effect of Venturi injector performance, which was positively correlated with outlet velocity, negatively to critical pressure, the minimal in-tube pressure, coefficient of local head loss, and fertilizer absorption ratio. For designing Venturi injector, contraction ratio should be reasonably selected according to the coefficient of local head loss and fertilizer absorption ratio.

  9. Hydraulics and pneumatics a technician's and engineer's guide

    Parr, Andrew


    Hydraulics and Pneumatics: A Technician's and Engineer's Guide provides an introduction to the components and operation of a hydraulic or pneumatic system. This book discusses the main advantages and disadvantages of pneumatic or hydraulic systems.Organized into eight chapters, this book begins with an overview of industrial prime movers. This text then examines the three different types of positive displacement pump used in hydraulic systems, namely, gear pumps, vane pumps, and piston pumps. Other chapters consider the pressure in a hydraulic system, which can be quickly and easily controlled

  10. Is high-resolution inverse characterization of heterogeneous river bed hydraulic conductivities needed and possible?

    W. Kurtz


    Full Text Available River–aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river–aquifer exchange fluxes tend to be strongly spatially variable, and it is an open research question to which degree river bed heterogeneity has to be represented in a model in order to achieve reliable estimates of river–aquifer exchange fluxes. This research question is addressed in this paper with the help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river–aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated–saturated subsurface hydrological flow problem including river–aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with the help of the ensemble Kalman filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high-resolution L fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher-resolution L fields (i.e. fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream–aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high

  11. Multiobjective Optimization of Effective Soil Hydraulic Properties on a Lysimeter from a Layered, Gravelly Vadose Zone

    Werisch, Stefan; Lennartz, Franz


    Estimation of effective soil hydraulic parameters for characterization of the vadose zone properties is important for many applications from prediction of solute and pesticide transport to water balance modeling in small catchments. Inverse modeling has become a common approach to infer the parameters of the water retention and hydraulic conductivity functions from dynamic experiments under varying boundary conditions. To gain further inside into to the water transport behavior of an agricultural field site with a layered, gravelly vadose zone, a lysimeter was taken and equipped with a total of 48 sensors (24 tensiometers and 24 water content probes). The sensors were arranged in 6 vertical arrays consisting of 4 sensor pairs, respectively. Pressure heads and water contents were measured in four depths in each of the arrays allowing for the estimation of the soil hydraulic properties of the three individual soil layers by inverse modeling. For each of the soil horizons, a separate objective function was defined to fit the model to the observation. We used the global multiobjective multimethod search algorithm AMALGAM (Vrugt et al., 2007) in combination with the water flow and solute transport model Hydrus1D (Šimúnek et al., 2008) to estimate the soil hydraulic properties of the Mualem van Genuchten model (van Genuchten, 1980). This experimental design served for the investigation of two important questions: a) do effective soil hydraulic properties at the lysimeter scale exist, more specifically: can a single representative parameter set be found which describes the hydraulic behavior in each of the arrays with acceptable performance? And b) which degree of freedom is necessary or required for an accurate description of the one dimensional water flow at each of the arrays? Effective soil hydraulic parameters were obtained for each of the sensor arrays individually, resulting in good agreement between the model predictions and the observations for the individual

  12. "Head versus heart"

    Paul Rozin


    Full Text Available Most American respondents give ``irrational,'' magical responses in a variety of situations that exemplify the sympathetic magical laws of similarity and contagion. In most of these cases, respondents are aware that their responses (usually rejections, as of fudge crafted to look like dog feces, or a food touched by a sterilized, dead cockroach are not ``scientifically'' justified, but they are willing to avow them. We interpret this, in some sense, as ``heart over head.'' We report in this study that American adults and undergraduates are substantially less likely to acknowledge magical effects when the judgments involve money (amount willing to pay to avoid an ``unpleasant'' magical contact than they are when using preference or rating measures. We conclude that in ``head-heart'' conflicts of this type, money tips the balance towards the former, or, in other words, that money makes the mind less magical.

  13. Development of New, Low-Head Hydropower Turbine - Modeling & Laboratory Test DE-EE0005426

    Krouse, Wayne [Hydro Green Energy, Westmont, IL (United States)


    Hydro Green Energy, LLC (HGE) will complete the design, fabrication and laboratory testing of a scaled, vertically stackable, low-head hydropower turbine called the Modular Bulb Turbine (MBT). HGE will also complete a summary report that includes the laboratory testing results and analysis of the tests. Project Goals: Design, model and test modular bulb turbine for installation in numerous HGE low-head hydropower projects at non-powered USACE dams. Project Results: The sub-scale prototype was tested successfully at a leading US hydraulic laboratory. Laboratory data results agreed well with predicted results from numerical modeling.

  14. "Head versus heart"


    Most American respondents give ``irrational,'' magical responses in a variety of situations that exemplify the sympathetic magical laws of similarity and contagion. In most of these cases, respondents are aware that their responses (usually rejections, as of fudge crafted to look like dog feces, or a food touched by a sterilized, dead cockroach) are not ``scientifically'' justified, but they are willing to avow them. We interpret this, in some sense, as ``heart over head.'' We report in this ...

  15. A novel energy recovery system for parallel hybrid hydraulic excavator.

    Li, Wei; Cao, Baoyu; Zhu, Zhencai; Chen, Guoan


    Hydraulic excavator energy saving is important to relieve source shortage and protect environment. This paper mainly discusses the energy saving for the hybrid hydraulic excavator. By analyzing the excess energy of three hydraulic cylinders in the conventional hydraulic excavator, a new boom potential energy recovery system is proposed. The mathematical models of the main components including boom cylinder, hydraulic motor, and hydraulic accumulator are built. The natural frequency of the proposed energy recovery system is calculated based on the mathematical models. Meanwhile, the simulation models of the proposed system and a conventional energy recovery system are built by AMESim software. The results show that the proposed system is more effective than the conventional energy saving system. At last, the main components of the proposed energy recovery system including accumulator and hydraulic motor are analyzed for improving the energy recovery efficiency. The measures to improve the energy recovery efficiency of the proposed system are presented.

  16. Optical fiber grating vibration sensor for vibration monitoring of hydraulic pump

    Zhang, Zhengyi; Liu, Chuntong; Li, Hongcai; He, Zhenxin; Zhao, Xiaofeng


    In view of the existing electrical vibration monitoring traditional hydraulic pump vibration sensor, the high false alarm rate is susceptible to electromagnetic interference and is not easy to achieve long-term reliable monitoring, based on the design of a beam of the uniform strength structure of the fiber Bragg grating (FBG) vibration sensor. In this paper, based on the analysis of the vibration theory of the equal strength beam, the principle of FBG vibration tuning based on the equal intensity beam is derived. According to the practical application of the project, the structural dimensions of the equal strength beam are determined, and the optimization design of the vibrator is carried out. The finite element analysis of the sensor is carried out by ANSYS, and the first order resonant frequency is 94.739 Hz. The vibration test of the sensor is carried out by using the vibration frequency of 35 Hz and the vibration source of 50 Hz. The time domain and frequency domain analysis results of test data show that the sensor has good dynamic response characteristics, which can realize the accurate monitoring of the vibration frequency and meet the special requirements of vibration monitoring of hydraulic pump under specific environment.

  17. Materials for a Stirling engine heater head

    Noble, J. E.; Lehmann, G. A.; Emigh, S. G.


    Work done on the 25-kW advanced Stirling conversion system (ASCS) terrestrial solar program in establishing criteria and selecting materials for the engine heater head and heater tubes is described. Various mechanisms contributing to incompatibility between materials are identified and discussed. Large thermal gradients, coupled with requirements for long life (60,000 h at temperature) and a large number of heatup and cooldown cycles (20,000) drive the design from a structural standpoint. The pressurized cylinder is checked for creep rupture, localized yielding, reverse plasticity, creep and fatigue damage, and creep ratcheting, in addition to the basic requirements for bust and proof pressure. In general, creep rupture and creep and fatigue interaction are the dominant factors in the design. A wide range of materials for the heater head and tubes was evaluated. Factors involved in the assessment were strength and effect on engine efficiency, reliability, and cost. A preliminary selection of Inconel 713LC for the heater head is based on acceptable structural properties but driven mainly by low cost. The criteria for failure, the structural analysis, and the material characteristics with basis for selection are discussed.

  18. Strength of Hard Alloys,

    Partial replacement of titanium carbide by tantalum carbide in three-phase WC-TiC-Co alloys tends to have a favorable effect on mechanical properties such as fatigue strength under bending and impact durability.

  19. Technology of load-sensitivity used in the hydraulic system of an all-hydraulic core rig

    XIN De-zhong; CHEN Song-ling; WANG Qing-feng


    The existing hydraulic system always have problems of temperature rise, run-ning stability and anti-interference of the implementation components, reliability of hydrau-lic components, maintenance difficulties, and other issues. With high efficiency, energy saving, reliability, easy operating, stable running, anti-interference ability, and other ad-vantages, the load-sensitive hydraulic system is more suitable for coal mine all-hydraulic core rig. Therefore, for the technical development of the coal mine all-hydraulic core rig, the load-sensitive technology employed by the rig should be of great significance.

  20. Trends in Design of Water Hydraulics

    Conrad, Finn


    The paper presents and discusses a R&D-view on trends in development and best practise in design of both low-pressure and high-pressure tap water hydraulic components and systems for motion control as well as open-ended solutions various industrial applications. The focus is on the advantages using...... ordinary tap water and the range of application areas are illustrated with examples, in particular within the food processing industry, humidification operations, water mist systems for fire fighting, high water pressure cleaners, water moisturising systems for wood processing, lumber drying process...... operate with pure water from the tap without additives of any kind. Hence water hydraulics takes the benefit of pure water as fluid being environmentally friendly, easy to clean sanitary design, non-toxic, non-flammable, inexpensive, readily available and easily disposable. The low-pressure tap water...

  1. The hydraulic fracturing of geothermal formations

    Naceur, K. Ben; Economides, M.J.; Schlumberger, Dowell


    Hydraulic fracturing has been attempted in geothermal formations as a means to stimulate both production and injection wells. Since most geothermal formations contain fissures and on occasion massive natural fissures, the production behavior of the man-made fractures results in certain characteristic trends. A model is offered that allows the presence of a finite or infinite conductivity fracture intercepting a fissured medium. The method is based on a numerical discretization of the formation allowing transient interporosity flow. Type curves for pressure drawdown and cumulative production are given for infinite acting and closed reservoirs. Since most of the fissured formations exhibit a degree of anisotropy, the effects of the orientation of the hydraulic fracture with respect to the fissure planes, and of the ratio between the directional permeabilities are then discussed. Guidelines are offered as to the size of appropriate stimulation treatments based on the observed fissured behavior of the reservoir.

  2. Plug & Play Control of Hydraulic Networks

    Jensen, Tom Nørgaard


    Process Control research program, which the work presented here is a part of. An industrial case study involving a large-scale hydraulic network with non-linear dynamics is studied. The hydraulic network underlies a district heating system, which provides heating water to a number of end-users in a city...... structure has the additional benefit that structural changes such as the addition or removal of end-users are easily implementable. In this work, the problem of controlling the pressure drop at the end-users to a constant reference value is considered. This is done by the use of pumps located both...... are considered. Some of the work considers control actions which are constrained to non-negative values only. This is due to the fact that the actuators in this type of system typically consist of centrifugal pumps which are only able to deliver non-negative actuation. Other parts of the work consider control...

  3. Concept Evaluation for Hydraulic Yaw System

    Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole


    a suspension system on a car, leading the loads away from the turbine structure. However, to realize a soft hydraulic yaw system a new design concept must be found. As a part of the development of the new concept a preliminary concept evaluation has been conducted, evaluating seven different hydraulic yaw......The yaw system is the subsystem on a wind turbine which ensures that the rotor plane of the turbine always is facing the wind direction. Studies from [1] show that a soft yaw system may be utilized to dampen the loads in the wind turbine structure. The soft yaw system operates much like...... investigation. Loads and yaw demands are based on the IEC 61400-1 standard for wind turbine design, and the loads for this examination are extrapolated from the HAWC2 aeroelastic design code. The concepts are based on a 5 MW off-shore turbine....

  4. New parameters influencing hydraulic runner lifetime

    Sabourin, M.; Thibault, D.; Bouffard, D. A.; Lévesque, M.


    Traditionally, hydraulic runner mechanical design is based on calculation of static stresses. Today, validation of hydraulic runner design in terms of reliability requires taking into account the fatigue effect of dynamics loads. A damage tolerant approach based on fracture mechanics is the method chosen by Alstom and Hydro-Québec to study fatigue damage in runners. This requires a careful examination of all factors influencing material fatigue behavior. Such material behavior depends mainly on the chemical composition, microstructure and thermal history of the component, and on the resulting residual stresses. Measurement of fracture mechanics properties of various steels have demonstrated that runner lifetime can be significantly altered by differences in the manufacturing process, although remaining in accordance with agreed practices and standards such as ASTM. Carbon content and heat treatment are suspected to influence fatigue lifetime. This will have to be investigated by continuing the current research.

  5. Pilot testing of a hydraulic bridge exciter

    Andersson Andreas


    Full Text Available This paper describes the development of a hydraulic bridge exciter and its first pilot testing on a full scale railway bridge in service. The exciter is based on a hydraulic load cylinder with a capacity of 50 kN and is intended for controlled dynamic loading up to at least 50 Hz. The load is applied from underneath the bridge, enabling testing while the railway line is in service. The system is shown to produce constant load amplitude even at resonance. The exciter is used to experimentally determine frequency response functions at all sensor locations, which serve as valuable input for model updating and verification. An FE-model of the case study bridge has been developed that is in good agreement with the experimental results.


    KE Zunrong; ZHU Yuquan; LING Xuan


    A new hydraulic actuator-hydraulic muscle (HM) is described, and the actuator's features and applications are analyzed, then a position servocontrol system in which HM is main actuator is set up. The mathematical model of the system is built up and several control strategies are discussed. Based on the mathematical model, simulation research and experimental investigation with subsection PID control, neural network self-adaptive PID control and single neuron self-adaptive PID control adopted respectively are carried out, and the results indicate that compared with PID control, neural network self-adaptive PID control and single neuron self-adaptive PID control don't need controlled system's accurate model and have fast response, high control accuracy and strong robustness, they are very suitable for HM position servo control system.

  7. Advanced Hydraulic Studies on Enhancing Particle Removal

    He, Cheng

    The removal of suspended solids and attached pollutants is one of the main treatment processes in wastewater treatment. This thesis presents studies on the hydraulic conditions of various particle removal facilities for possible ways to increase their treatment capacity and performance by utilizing...... and improving hydraulic conditions. Unlike most traditional theses which usually focus only on one particular subject of study, this thesis contains four relatively independent studies which cover the following topics: a newly proposed particle settling enhancement plate, the redesign of the inlet zone......, introduction and conclusions as well as the study results. All studies were carried out with a combination of numerical model and measurements. In the first part of the thesis a new concept of using a vortex to increase particle removal from liquid was proposed and the new particle settling enhancement plates...

  8. Thermal Hydraulic Design of PWT Accelerating Structures

    Yu, David; Chen Ping; Lundquist, Martin; Luo, Yan


    Microwave power losses on the surfaces of accelerating structures will transform to heat which will deform the structures if it is not removed in time. Thermal hydraulic design of the disk and cooling rods of a Plane Wave Transformer (PWT) structure is presented. Experiments to measure the hydraulic (pressure vs flow rate) and cooling (heat removed vs flow rate) properties of the PWT disk are performed, and results compared with simulations using Mathcad models and the COSMOSM code. Both experimental and simulation results showed that the heat deposited on the structure could be removed effectively using specially designed water-cooling circuits and the temperature of the structure could be controlled within the range required.

  9. Hydraulic conductivity and diffusion characterization of GCLs

    Mukunoki, T.; Rowe, R.K.; Li, H.M.; Sangam, H.P.; Hurst, P.; Bathurst, R.J. [Queen' s Univ., Kingston, ON (Canada)]|[Royal Military Coll. of Canada, Kingston, ON (Canada); Badv, K. [Urmia Univ. (Iran, Islamic Republic of)


    This paper reports on the characterization of the hydraulic conductivity and diffusion of a geosynthetic clay liner (GCL) installed at a site off the southeast coast of Baffin Island, in the Canadian Arctic, following different levels of freeze-thaw exposure and under low temperature conditions. The authors presented a summary of the results obtained for hydraulic conductivity tests on GCLs subjected to freeze-thaw cycles, and specimens permeated with jet fuel (Arctic diesel). They also reported on diffusion tests conducted at 22 Celsius and 5 Celsius, followed by a discussion of the effect of temperature. The results indicate that there is no significant impact on GCL performance due to freeze-thaw cycles, permeation by jet fuel or diffusion at the lower temperatures expected in the north for the short term (up to approximately four years). Additional studies are needed to confirm long term behaviour. 24 refs., 2 tabs., 4 figs.

  10. Thermal-hydraulic analysis of nuclear reactors

    Zohuri, Bahman


    This text covers the fundamentals of thermodynamics required to understand electrical power generation systems and the application of these principles to nuclear reactor power plant systems. It is not a traditional general thermodynamics text, per se, but a practical thermodynamics volume intended to explain the fundamentals and apply them to the challenges facing actual nuclear power plants systems, where thermal hydraulics comes to play.  Written in a lucid, straight-forward style while retaining scientific rigor, the content is accessible to upper division undergraduate students and aimed at practicing engineers in nuclear power facilities and engineering scientists and technicians in industry, academic research groups, and national laboratories. The book is also a valuable resource for students and faculty in various engineering programs concerned with nuclear reactors. This book also: Provides extensive coverage of thermal hydraulics with thermodynamics in nuclear reactors, beginning with fundamental ...

  11. The Hydraulic Ram (Or Impulse) Pump

    Mills, Allan


    The hydraulic impulse pump utilizes a fraction of the momentum of a flowing stream to lift a small portion of that water to a higher level. There it may be accumulated in an elevated cistern to provide sufficient water for several families, for the pump works 24 h a day with no additional source of energy. The operation of the pump is described,…

  12. Hydraulic Aspects of Vegetation Maintanence in Streams

    Larsen, Torben; Vestergaard, Kristian


    This paper describes the importance of the underwater vegetation on Danish streams and some of the consequences of vegetation maintenance. the influence of the weed on the hydraulic conditions is studied through experiments in a smaller stream and the effect of cutting channels through the weed...... is measured. A method for predicting the Manning's n as a function of the discharge conditions is suggested, and also a working hypothesis for predictions of the effect of channel cutting is presented....

  13. Rapid Hydraulic Assessment for Stream Restoration


    account the hydraulic conditions of the stream being restored. This is true whether the project involves a few feet of bank stabilization or several...coefficient, α, expresses a correction for nonuniformity in the velocity distribution, and in most applications this value is assumed to be 1 or read from...a table (e.g., Chow 1959, p.28). The depth and slope angle terms can be replaced by a vertical expression of the depth, y, because in most rivers

  14. Estimation of ground water hydraulic parameters

    Hvilshoej, Soeren


    The main objective was to assess field methods to determine ground water hydraulic parameters and to develop and apply new analysis methods to selected field techniques. A field site in Vejen, Denmark, which previously has been intensively investigated on the basis of a large amount of mini slug tests and tracer tests, was chosen for experimental application and evaluation. Particular interest was in analysing partially penetrating pumping tests and a recently proposed single-well dipole test. Three wells were constructed in which partially penetrating pumping tests and multi-level single-well dipole tests were performed. In addition, multi-level slug tests, flow meter tests, gamma-logs, and geologic characterisation of soil samples were carried out. In addition to the three Vejen analyses, data from previously published partially penetrating pumping tests were analysed assuming homogeneous anisotropic aquifer conditions. In the present study methods were developed to analyse partially penetrating pumping tests and multi-level single-well dipole tests based on an inverse numerical model. The obtained horizontal hydraulic conductivities from the partially penetrating pumping tests were in accordance with measurements obtained from multi-level slug tests and mini slug tests. Accordance was also achieved between the anisotropy ratios determined from partially penetrating pumping tests and multi-level single-well dipole tests. It was demonstrated that the partially penetrating pumping test analysed by and inverse numerical model is a very valuable technique that may provide hydraulic information on the storage terms and the vertical distribution of the horizontal and vertical hydraulic conductivity under both confined and unconfined aquifer conditions. (EG) 138 refs.

  15. Monitoring hydraulic fracturing with seismic emission volume

    Niu, F.; Tang, Y.; Chen, H.; TAO, K.; Levander, A.


    Recent developments in horizontal drilling and hydraulic fracturing have made it possible to access the reservoirs that are not available for massive production in the past. Hydraulic fracturing is designed to enhance rock permeability and reservoir drainage through the creation of fracture networks. Microseismic monitoring has been proven to be an effective and valuable technology to image hydraulic fracture geometry. Based on data acquisition, seismic monitoring techniques have been divided into two categories: downhole and surface monitoring. Surface monitoring is challenging because of the extremely low signal-to-noise ratio of the raw data. We applied the techniques used in earthquake seismology and developed an integrated monitoring system for mapping hydraulic fractures. The system consists of 20 to 30 state-of-the-art broadband seismographs, which are generally about hundreds times more sensible than regular geophones. We have conducted two experiments in two basins with very different geology and formation mechanism in China. In each case, we observed clear microseismic events, which may correspond to the induced seismicity directly associated with fracturing and the triggered ones at pre-existing faults. However, the magnitude of these events is generally larger than magnitude -1, approximately one to two magnitudes larger than those detected by downhole instruments. Spectrum-frequency analysis of the continuous surface recordings indicated high seismic energy associated with injection stages. The seismic energy can be back-projected to a volume that surrounds each injection stage. Imaging seismic emission volume (SEV) appears to be an effective way to map the stimulated reservior volume, as well as natural fractures.

  16. Partially decoupled modeling of hydraulic fracturing processes

    Settari, A.; Puchyr, P.J.; Bachman, R.C. (Simtech Consulting Services, Calgary (CA))


    A new method of partial decoupling of the problem of modeling a hydraulic fracture in a reservoir is described. According to the authors this approach has significant advantages over previous methods with fully coupled or completely uncoupled models. Better accuracy can be achieved in modeling the fracture propagation, and the new system is very efficient and versatile. Virtually any reservoir model can be used for predicting postfracture productivity. Examples of single- and multiphase applications for modeling fractured wells are discussed.

  17. Effects of substrate properties on the hydraulic and thermal behavior of a green roof

    Sandoval, V. P.; Suarez, F. I.; Victorero, F.; Bonilla, C.; Gironas, J. A.; Vera, S.; Bustamante, W.; Rojas, V.; Pasten, P.


    Green roofs are a sustainable urban development solution that incorporates a growing media (also known as substrate) and vegetation into infrastructures to reach additional benefits such as the reduction of: rooftop runoff peak flows, roof surface temperatures, energy utilized for cooling/heating buildings, and the heat island effect. The substrate is a key component of the green roof that allows achieving these benefits. It is an artificial soil that has an improved behavior compared to natural soils, facilitating vegetation growth, water storage and typically with smaller densities to reduce the loads over the structures. Therefore, it is important to study the effects of substrate properties on green roof performance. The objective of this study is to investigate the physical properties of four substrates designed to improve the behavior of a green roof, and to study their impact on the efficiency of a green roof. The substrates that were investigated are: organic soil; crushed bricks; a mixture of mineral soil with perlite; and a mixture of crushed bricks and organic soil. The thermal properties (thermal conductivity, volumetric heat capacity and thermal diffusivity) were measured using a dual needle probe (Decagon Devices, Inc.) at different saturation levels, and the hydraulic properties were measured with a constant head permeameter (hydraulic conductivity) and a pressure plate extractor (water retention curve). This characterization, combined with numerical models, allows understanding the effect of these properties on the hydraulic and thermal behavior of a green roof. Results show that substrates composed by crushed bricks improve the thermal insulation of infrastructures and at the same time, retain more water in their pores. Simulation results also show that the hydraulic and thermal behavior of a green roof strongly depends on the moisture content prior to a rainstorm.

  18. Polyacrylamide effect on hydraulic conductivity of hardsetting soils in Northeast of Brazil

    Silva, Laércio; Almeida, Brivaldo; Melo, Diego; Marques, Karina; Almeida, Ceres


    Among soil hydro-physical properties, hydraulic conductivity is more sensitive to changes in soil structure. Hydraulic conductivity describes the ease with which a fluid (usually water) can move through pore spaces or fractures. It depends on the intrinsic permeability of the material and on the degree of saturation, and on the density and viscosity of the fluid. Hardsetting soils present very low hydraulic conductivity values. When dry, these soils show high penetration resistance and consistency extremely hard, but change to friable when moist. In this condition are poorly structured, slaking when moist, limit agricultural machinery use and it may reduce the growth of the root system. In Brazil, these soils occur throughout of coastal zone in flat areas called "coastal tableland". Chemical ameliorant, such as polymers based on anionic polyacrylamide (PAM), improve hydraulic conductivity of soil in hardsetting soils. The primary functions of polyacrylamide soil conditioners are to increase soil tilth, aeration, and porosity and reduce compaction and water run-off. PAM effect is attributed to its ability to expand when placed in water, storing it in soil pore space, releasing it gradually to the plants. This process occurs by reducing the water flow through the pores of the soil, due to water molecules can be absorbed by PAM, providing water gradually. Thus, this study tested the hypothesis that PAM reduces the soil hardsetting character. The area is located in coastal zone in Goiana city, Pernambuco, northeastern of Brazil. This soil is typical hardsetting soil. Intact soil cores were collected from four horizons until 70cm depth. In the laboratory, the soil cores were saturated with different PAM concentrations (0.01, 0.005, 0.00125%) and H2O (control). Saturated hydraulic conductivity (Ksat) was determined using a constant head method, according to Klute and Dirksen (1986). Four replicates were used for each horizon and Tukey test at 5% probability was used by

  19. Flow characteristics of variable hydraulic transformer

    杨冠中; 姜继海


    A new kind of hydraulic transformer, called variable hydraulic transformer (VHT), is proposed to control its load flow rate. The hydraulic transformer evolves from a pressure transducer to a power transducer. The flow characteristics of VHT, such as its instantaneous flow rates, average flow rates, and flow pulsations in the ports, are investigated. Matlab software is used to simulate and calculate. There are five controlled angles of the port plate that can help to define the flow characteristics of VHT. The relationships between the flow characteristics and the structure in VHT are shown. Also, the plus−minus change of the average flow rates and the continuity of the instantaneous flow rates in the ports are presented. The results demonstrate the performance laws of VHT when the controlled angles of the port plate and of the swash plate change. The results also reveal that the special principle of the flow pulsation in the ports and the jump points of the instantaneous curves are the two basic causes of its loud noise, and that the control angles of the port plate and the swash plate and the pressures in the ports are the three key factors of the noise.

  20. Measuring Disturbance Impact on Soil Hydraulic Properties

    Hinshaw, S.; Mirus, B. B.


    Disturbances associated with land cover change such as forest clearing and mono-cropping can have a substantial impact on soil-hydraulic properties, which in turn have a cascading impact on surface and near-surface hydrologic response. Although disturbances and vegetation change can alter soil-water retention and conductivity relations, hydrologic models relying on traditional soil-texture based pedotransfer functions would not be able to capture the disturbance impact on infiltration and soil-moisture storage. Therefore, in-situ estimates of characteristic curves of soil water retention and hydraulic conductivity relations are needed to understand and predict hydrologic impacts of land cover change. We present a method for in-situ estimates of effective characteristic curves that capture hysteretic soil-water retention properties at the plot scale. We apply this method to two different forest treatments and in urban settings to investigate the impact of land-use disturbances on soil-hydraulic properties. We compare our in-situ estimation method to results for simple pedotransfer functions to illustrate how this approach can improve understanding of disturbance impacts on hydrologic processes and function.