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1

Use of Fluoroplastics in Packing Assemblies of Hydraulic Units  

Microsoft Academic Search

Hydraulic power drives (actuators) are widely used in various branches of engineering. Safety of equipment operation and product quality depend a great deal on the reliability of these drives. Experience of operation of hydraulic units shows [1] that in many cases their malfunctioning (failure) is due to packing assemblies. For instance, of the total number of failures, those due to

G. V. Bozhko

2001-01-01

2

Hydraulically refueled battery employing a packed bed metal particle electrode  

DOEpatents

A secondary zinc air cell, or another selected metal air cell, employing a spouted/packed metal particle bed and an air electrode is described. More specifically, two embodiments of a cell, one that is capable of being hydraulically recharged, and a second that is capable of being either hydraulically or electrically recharged. Additionally, each cell includes a sloped bottom portion to cause stirring of the electrolyte/metal particulate slurry when the cell is being hydraulically emptied and refilled during hydraulically recharging of the cell. 15 figs.

Siu, S.C.; Evans, J.W.

1998-12-15

3

Recover Power with Hydraulic Motors  

E-print Network

Anywhere liquid pressure is reduced across a throttling device, there is a potential application for a hydraulic power recovery motor (HPRM). Cost of power makes HPRM's attractive with recoveries as small as 25 hp on a continuous basis. When...

Brennan, J. R.

1982-01-01

4

Fluid Power/Basic Hydraulics. Instructor's Guide.  

ERIC Educational Resources Information Center

This guide is designed to assist industrial vocational instructors in teaching a course on fluid power and basic hydraulics. Covered in the unit on the basics of fluid power and hydraulics are the following topics: the fundamentals of fluid power and hydraulics, basic hydraulic circuits, and servicing a hydraulic jack. The second unit, consisting…

Stanbery, Richard

5

Hydraulic Wind Power Transfer Technology Afshin Izadian  

E-print Network

Hydraulic Wind Power Transfer Technology Afshin Izadian Purdue School of Engineering and Technology wind power, and by doing so, it reduces the capital equipment of the entire power plant and substantially increases power transfer efficiency. The system operates when a wind-driven hydraulic pump

Zhou, Yaoqi

6

Power Consumption Prediction and Power-Aware Packing in Consolidated  

E-print Network

Power Consumption Prediction and Power-Aware Packing in Consolidated Environments Jeonghwan Choi the power consumption of groups of colocated applications. Such characterization is crucial for effective prediction and enforcement of appropriate limits on power consumption--power budgets--within the data center

Urgaonkar, Bhuvan

7

Space Shuttle Upgrades Advanced Hydraulic Power System  

NASA Technical Reports Server (NTRS)

Three Auxiliary Power Units (APU) on the Space Shuttle Orbiter each provide 145 hp shaft power to a hydraulic pump which outputs 3000 psi hydraulic fluid to 41 hydraulic actuators. A hydrazine fuel powered APU utilized throughout the Shuttle program has undergone many improvements, but concerns remain with flight safety, operational cost, critical failure modes, and hydrazine related hazards. The advanced hydraulic power system (AHPS), also known as the electric APU, is being evaluated as an upgrade to replace the hydrazine APU. The AHPS replaces the high-speed turbine and hydrazine fuel supply system with a battery power supply and electric motor/pump that converts 300 volt electrical power to 3000 psi hydraulic power. AHPS upgrade benefits include elimination of toxic hydrazine propellant to improve flight safety, reduction in hazardous ground processing operations, and improved reliability. Development of this upgrade provides many interesting challenges and includes development of four hardware elements that comprise the AHPS system: Battery - The battery provides a high voltage supply of power using lithium ion cells. This is a large battery that must provide 28 kilowatt hours of energy over 99 minutes of operation at 300 volts with a peak power of 130 kilowatts for three seconds. High Voltage Power Distribution and Control (PD&C) - The PD&C distributes electric power from the battery to the EHDU. This 300 volt system includes wiring and components necessary to distribute power and provide fault current protection. Electro-Hydraulic Drive Unit (EHDU) - The EHDU converts electric input power to hydraulic output power. The EHDU must provide over 90 kilowatts of stable, output hydraulic power at 3000 psi with high efficiency and rapid response time. Cooling System - The cooling system provides thermal control of the Orbiter hydraulic fluid and EHDU electronic components. Symposium presentation will provide an overview of the AHPS upgrade, descriptions of the four hardware elements, and a summary of development results to date.

2004-01-01

8

Save energy with hydraulic power recovery turbines  

Microsoft Academic Search

The reverse running pump is used as a means of recovering power from process units but lacks the controlability and efficiency of hydraulic power recovery turbines. A comparison of these two devices is presented and also a discussion of why hydraulic turbines can be applied at a lower overall cost.

Franzke

1975-01-01

9

HYDRODYNAMIC BEHAVIOUR OF A BIOLOGICAL PACKED BED UNDER DIFFERENT HYDRAULIC AND ORGANIC LOADING  

Microsoft Academic Search

The hydraulic characteristics of a biological laboratory packed bed, filled with a volcanic stone (puzzolane), have been experimentally investigated through tracer tests. Fifteen sets of assays at flow rates from 1 to 2.5 L h -1 in clean conditions and for two different superficial organic loadings (4 and 52 mg C L-1) were performed The residential time distribution (RTD) curves

A. Albuquerque; F. Santana

2004-01-01

10

Hydraulically powered dissimilar teleoperated system controller design  

SciTech Connect

This paper will address two issues associated with the implementation of a hydraulically powered dissimilar master-slave teleoperated system. These issues are the overall system control architecture and the design of robust hydraulic servo controllers for the position control problem. Finally, a discussion of overall system performance on an actual teleoperated system will be presented.

Jansen, J.F.; Kress, R.L.

1996-04-01

11

8. HIGH POWER SPRAY IN MEN'S PACK ROOM. Hot ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. HIGH POWER SPRAY IN MEN'S PACK ROOM. - Hot Springs National Park Bathhouse Row, Maurice Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

12

Lightweight, Flexible, Thin, Integrated Solar-Power Packs  

NASA Technical Reports Server (NTRS)

Lightweight, flexible, thin, one-piece, solar-power packs are undergoing development. Each power pack of this type is a complete, modular, integrated power-supply system comprising three power subsystems that, in conventional practice, have been constructed as separate units and connected to each other by wires. These power packs are amenable to a variety of uses: For example, they could be laminated to the tops of tents and other shelters to provide or augment power for portable electronic equipment in the field, and they could be used as power sources for such small portable electronic systems as radio transceivers (including data relays and cellular telephones), laptop computers, video camcorders, and Global Positioning System receivers.

Hanson, Robert R.

2004-01-01

13

Centre Hydraulic Power Supply Unit University of Saskatchewan -Mechanical Engineering Fluid Power and Controls  

E-print Network

Centre Hydraulic Power Supply Unit University of Saskatchewan - Mechanical Engineering ­ Fluid Power and Controls ID: FP0003 Rev: 001 Date: May 31, 2010 Page: 1 of 7 Centre Hydraulic Power Supply;Centre Hydraulic Power Supply Unit University of Saskatchewan - Mechanical Engineering ­ Fluid Power

Saskatchewan, University of

14

HYPower Hydraulic Power Supply Unit University of Saskatchewan -Mechanical Engineering Fluid Power and Controls  

E-print Network

HYPower Hydraulic Power Supply Unit University of Saskatchewan - Mechanical Engineering ­ Fluid Power and Controls ID: FP0002 Rev: 002 Date: May 31, 2010 Page: 1 of 7 Hydraulic Power Supply (HYPower-5462 Secondary Contact: #12;HYPower Hydraulic Power Supply Unit University of Saskatchewan - Mechanical

Saskatchewan, University of

15

East Hydraulic Power Supply Unit University of Saskatchewan -Mechanical Engineering Fluid Power and Controls  

E-print Network

East Hydraulic Power Supply Unit University of Saskatchewan - Mechanical Engineering ­ Fluid Power and Controls ID: FP0004 Rev: 001 Date: May 31, 2010 Page: 1 of 7 East Hydraulic Power Supply and Test Bench. Approved By: Primary Contact: Doug Bitner Rm: 1B15.1 966-5462 Secondary Contact: #12;East Hydraulic Power

Saskatchewan, University of

16

Control\\/structure interaction in hydraulic power steering systems  

Microsoft Academic Search

A hydraulic power steering system uses feedback control to assist the driver in applying steering input commands to the vehicle. A small vibration, known as shudder, can occur in the system during low speed steering manoeuvres. It is shown that power steering shudder is a closed-loop limit cycle caused by the interaction of the hydraulic and structural dynamics of the

Gary R. Ferries; R. Larry Arbanas

1997-01-01

17

Control issues for a hydraulically powered dissimilar teleoperated system  

SciTech Connect

This paper will address two issues associated with the implementation of a hydraulically powered dissimilar master-slave teleoperated system. These issues are the overall system control architecture and the design of robust hydraulic servo controllers for the position control problem. Finally, a discussion of overall system performance on an actual teleoperated system will be presented. (Schilling`s Titan II hydraulic manipulators are the slave manipulators and the master manipulators are from the Oak Ridge National Laboratory-developed Advanced Servo Manipulator.)

Jansen, J.F.; Kress, R.L.

1995-12-31

18

Power-law friction in closely-packed granular materials  

E-print Network

In order to understand the nature of friction in closely-packed granular materials, a discrete element simulation on granular layers subjected to isobaric plain shear is performed. It is found that the friction coefficient increases as the power of the shear rate, the exponent of which does not depend on the material constants. Using a nondimensional parameter that is known as the inertial number, the power-law can be cast in a generalized form so that the friction coefficients at different confining pressures collapse on the same curve. We show that the volume fraction also obeys a power-law.

Takahiro Hatano

2007-05-08

19

Analysis of response lag in hydraulic power steering system  

Microsoft Academic Search

Response lag during rapid steering in the hydraulic power steering system of a vehicle was analyzed with a numerical simulation mathematical model which considered the propagation of pressure waves in a hydraulic line and visco-elastic characteristics of the hose. Pressure perturbation by pump flow ripple and self-excited vibration which were incompatible with the response, were analyzed by the simulation. From

Shinji Nishimura; Tsugiharu Matsunaga

2000-01-01

20

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.  

Code of Federal Regulations, 2012 CFR

...EQUIPMENT AND SYSTEMS Materials and... § 128.240 Hydraulic or pneumatic power...standard valves) for hydraulic or pneumatic power and control systems must meet the...Any non-standard hydraulic or...

2012-10-01

21

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.  

Code of Federal Regulations, 2011 CFR

...EQUIPMENT AND SYSTEMS Materials and... § 128.240 Hydraulic or pneumatic power...standard valves) for hydraulic or pneumatic power and control systems must meet the...Any non-standard hydraulic or...

2011-10-01

22

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.  

Code of Federal Regulations, 2014 CFR

...EQUIPMENT AND SYSTEMS Materials and... § 128.240 Hydraulic or pneumatic power...standard valves) for hydraulic or pneumatic power and control systems must meet the...Any non-standard hydraulic or...

2014-10-01

23

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.  

Code of Federal Regulations, 2013 CFR

...EQUIPMENT AND SYSTEMS Materials and... § 128.240 Hydraulic or pneumatic power...standard valves) for hydraulic or pneumatic power and control systems must meet the...Any non-standard hydraulic or...

2013-10-01

24

The Free Piston Power Pack: Sustainable Power for Hybrid Electric Vehicles  

Microsoft Academic Search

The Free Piston Power Pack (FP3) represents a new concept in the design of free piston engines. The FP3 is a free piston engine with an integral generator for electrical power output. Its novel features are an integral compressor and a passive intake valve located in the head of the piston. These improvements eliminate undesirable problems that affect conventional free

Douglas Carter; Edward Wechner

25

Two dimensional packing: the power of rotation Leah Epstein y  

E-print Network

-dimensional packing problem of packing rectangles into unit squares. However our problem is slightly di#11;er- ent are unit squares. The items are rectangles of sides bounded by 1. The items arrive one by one, each in the study of two-dimensional packing problems. In such problems the input items are rectangles which need

Epstein, Leah

26

Hydraulics.  

ERIC Educational Resources Information Center

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)…

Decker, Robert L.; Kirby, Klane

27

A Method for Optimal Scheduling of Hydraulically Coupled Power Plants  

NASA Astrophysics Data System (ADS)

This paper presents a novel method for optimal scheduling of hydraulically coupled power plants with operation constraints. In a hydro thermal power system, the operation schedule of hydro plants becomes more important to reduce the fuel cost of thermal plants, as the ratio of the hydro plants becomes larger. But hydraulically coupled power plants have some specific constraints depending upon the operations of the upstream plants, which makes the optimization problem more complicated. The proposed method is based on a decision process of an expert operation planner. First it calculates the most economical operation schedule without respect to the operation constraints of hydraulically coupled power plants. If this initial schedule violates the operation constraints of hydraulically coupled power plants, it is modified successively so as to dissolve each violation with most economical manner. The method is heuristic, but it can be widely applied to general problems as specify the river systems characteristics. Due to the above-mentioned method, the obtained schedule becomes easily acceptable because the intermediate schedules can be checked by the operation planners.

Kusano, Takashi; Sakurai, Takayoshi; Saito, Yutaka; Hiromasa, Katsutoshi; Kato, Masakazu; Nagata, Junichi

28

Distillation columns containing structured packings: A comprehensive model for their performance. 1. Hydraulic models  

Microsoft Academic Search

A mechanistically-based model has been developed to aid the analysis and design of distillation columns containing structured packings of the corrugated plate type. The model encompasses the important, and related, parameters of liquid holdup, pressure drop, flooding, and mass-transfer efficiency. Since it deals with the countercurrent contacting of liquid with gas or vapor, the model may also be applied to

J. Antonio Rocha; Jose L. Bravo; James R. Fair

1993-01-01

29

Mobile hydraulic power supply: Liquid piston Stirling engine pump  

Microsoft Academic Search

Conventional mobile hydraulic power supplies involve numerous kinematic connections and are limited by the efficiency, noise, and emissions of internal combustion engines. The Stirling cycle possesses numerous benefits such as the ability to operate from any heat source, quiet operation, and high theoretical efficiency. The Stirling engine has seen limited success due to poor heat transfer in the working chambers,

James D. Van de Ven

2009-01-01

30

Modeling and Co-simulation of Hydraulic Power Steering System  

Microsoft Academic Search

Hydraulic power steering systems, which can provide large steering assist force, are widely used for heavy- duty commercial vehicles to enhance the driving comfort. Such systems have great influences on vehicle controllability, steering stability and safety. However, interpolated table from experiment data was used as the assist force to study the vehicle dynamics in many previous works, so the transient

Ying Sun; Ping He; Yunqing Zhang; Liping Chen

2011-01-01

31

Low-power microfluidic electro-hydraulic pump (EHP).  

PubMed

Low-power electrolysis-based microfluidic pumps utilizing the principle of hydraulics, integrated with microfluidic channels in polydimethylsiloxane (PDMS) substrates, are presented. The electro-hydraulic pumps (EHPs), consisting of electrolytic, hydraulic and fluidic chambers, were investigated using two types of electrodes: stainless steel for larger volumes and annealed gold electrodes for smaller-scale devices. Using a hydraulic fluid chamber and a thin flexible PDMS membrane, this novel prototype successfully separates the reagent fluid from the electrolytic fluid, which is particularly important for biological and chemical applications. The hydraulic advantage of the EHP device arises from the precise control of flow rate by changing the electrolytic pressure generated, independent of the volume of the reagent chamber, mimicking the function of a hydraulic press. Since the reservoirs are pre-filled with reagents and sealed prior to testing, external fluid coupling is minimized. The stainless steel electrode EHPs were manufactured with varying chamber volume ratios (1 : 1 to 1 : 3) as a proof-of-concept, and exhibited flow rates of 1.25 to 30 microl/min with electrolysis-based actuation at 2.5 to 10 V(DC). The miniaturized gold electrode EHPs were manufactured with 3 mm diameters and 1 : 1 chamber volume ratios, and produced flow rates of 1.24 to 7.00 microl/min at 2.5 to 10 V(AC), with a higher maximum sustained pressure of 343 KPa, suggesting greater device robustness using methods compatible with microfabrication. The proposed technology is low-cost, low-power and disposable, with a high level of reproducibility, allowing for ease of fabrication and integration into existing microfluidic lab-on-a-chip and analysis systems. PMID:20024053

Lui, Clarissa; Stelick, Scott; Cady, Nathaniel; Batt, Carl

2010-01-01

32

Hydraulics.  

ERIC Educational Resources Information Center

These instructional materials provide an orientation to hydraulics for use at the postsecondary level. The first of 12 sections presents an introduction to hydraulics, including discussion of principles of liquids, definitions, liquid flow, the two types of hydraulic fluids, pressure gauges, and strainers and filters. The second section identifies…

Engelbrecht, Nancy; And Others

33

Sound power measurements on the M1E1 engine and total power pack  

NASA Astrophysics Data System (ADS)

A new technique to measure power was used to gather one-third octave emissions data on the M1E1 engine (AGT 1500) at the Stratford Army Engine Plant, CT and on the M1E1 power pack at Aberdeen Proving Ground, MD. To calculate sound power, acoustic intensity (the product of the scaler pressure and the vector velocity) was measured and integrated over an arbitrary surface enclosing the source. The data gathered and test results show this new technique is very powerful and robust and is applicable to many machinery quieting, source emission, or sound transmission measurements.

Schomer, P. D.

1983-05-01

34

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Hydraulic or pneumatic power and control-materials...Materials and Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials...flanges, and standard valves) for hydraulic or pneumatic power and control...

2010-10-01

35

49 CFR 173.172 - Aircraft hydraulic power unit fuel tank.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Aircraft hydraulic power unit fuel tank. 173.172 Section...Class 1 and Class 7 § 173.172 Aircraft hydraulic power unit fuel tank. Aircraft hydraulic power unit fuel tanks containing a...

2010-10-01

36

A NEW PASSIVE CONTROLLER FOR A HYDRAULIC HUMAN POWER AMPLIFIER Perry Y. Li  

E-print Network

A NEW PASSIVE CONTROLLER FOR A HYDRAULIC HUMAN POWER AMPLIFIER Perry Y. Li Department of Mechanical A new, intrinsically passive controller for hydraulic human power amplifier is presented. The hydraulic that humans manipulate directly, but have the ability to attenuate or amplify the apparent power

Li, Perry Y.

37

Nonlinear State Space Model of a Hydraulic Wind Power Transfer Masoud Vaezi1  

E-print Network

Nonlinear State Space Model of a Hydraulic Wind Power Transfer Masoud Vaezi1 , Majid Deldar1 1, IUPUI. Gearless hydraulic wind power systems are considered as nonlinear models because of some discrete nonlinear governing equations for the elements in the proposed hydraulic wind power configuration. Nonlinear

Zhou, Yaoqi

38

Powered orthosis and attachable power-assist device with Hydraulic Bilateral Servo System.  

PubMed

This paper discusses the developments and control strategies of exoskeleton-type robot systems for the application of an upper limb powered orthosis and an attachable power-assist device for care-givers. Hydraulic Bilateral Servo System, which consist of a computer controlled motor, parallel connected hydraulic actuators, position sensors, and pressure sensors, are installed in the system to derive the joint motion of the exoskeleton arm. The types of hydraulic component structure and the control strategy are discussed in relation to the design philosophy and target joints motions. PMID:24110321

Ohnishi, Kengo; Saito, Yukio; Oshima, Toru; Higashihara, Takanori

2013-01-01

39

46 CFR 111.97-5 - Electric and hydraulic power supply.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Electric and hydraulic power supply. 111.97-5 Section...Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric...operated watertight door system that uses a hydraulic system common to more than one...

2010-10-01

40

Simulation and experimental validation study on the drive performance of a new hydraulic power assist system  

Microsoft Academic Search

Hydraulic power assist system is a hydraulic regeneration system, which can improve fuel economy significantly coupled to a conventional bus operating in urban traffic. This paper presents a new hydraulic power assist system-HPAS. For the special configuration and control strategy, HPAS can be easily installed in an old bus as well as a new one. In this paper, more attention

Guo-Qing Liu; Ye-Cui Yan; Jie Chen; Tian-Ming Na

2009-01-01

41

Hydraulics.  

ERIC Educational Resources Information Center

Designed for use in courses where students are expected to become proficient in the area of hydraulics, including diesel engine mechanic programs, this curriculum guide is comprised of fourteen units of instruction. Unit titles include (1) Introduction, (2) Fundamentals of Hydraulics, (3) Reservoirs, (4) Lines, Fittings, and Couplers, (5) Seals,…

Decker, Robert L.

42

Coupled Monte Carlo neutronics and thermal hydraulics for power reactors  

SciTech Connect

The availability of high performance computing resources enables more and more the use of detailed Monte Carlo models even for full core power reactors. The detailed structure of the core can be described by lattices, modeled by so-called repeated structures e.g. in Monte Carlo codes such as MCNP5 or MCNPX. For cores with mainly uniform material compositions, fuel and moderator temperatures, there is no problem in constructing core models. However, when the material composition and the temperatures vary strongly a huge number of different material cells must be described which complicate the input and in many cases exceed code or memory limits. The second problem arises with the preparation of corresponding temperature dependent cross sections and thermal scattering laws. Only if these problems can be solved, a realistic coupling of Monte Carlo neutronics with an appropriate thermal-hydraulics model is possible. In this paper a method for the treatment of detailed material and temperature distributions in MCNP5 is described based on user-specified internal functions which assign distinct elements of the core cells to material specifications (e.g. water density) and temperatures from a thermal-hydraulics code. The core grid itself can be described with a uniform material specification. The temperature dependency of cross sections and thermal neutron scattering laws is taken into account by interpolation, requiring only a limited number of data sets generated for different temperatures. Applications will be shown for the stationary part of the Purdue PWR benchmark using ATHLET for thermal- hydraulics and for a generic Modular High Temperature reactor using THERMIX for thermal- hydraulics. (authors)

Bernnat, W.; Buck, M.; Mattes, M. [Institut fuer Kernenergetik und Energiesysteme IKE, Universitaet Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Zwermann, W.; Pasichnyk, I.; Velkov, K. [Gesellschaft fuer Anlagen- und Reaktorsicherheit GRS MbH, Forschungszentrum, Boltzmannstrase 14, 85748 Garching (Germany)

2012-07-01

43

A composite algorithm for flow rate reduction and stable body trajectory generation in a hydraulic actuated quadruped robot with kinematic redundancy  

Microsoft Academic Search

A hydraulic actuator has a various merits. It has a small size and a high power-to-weight ratio. So it is able to generate high torque in small size actuator. These features of hydraulic actuator are very useful for a walking robot. However, the hydraulic actuator needs a hydraulic power-pack which supplies pressure and flow. Usually, a big and heavy power-pack

Taeju Kim; Byung-Ju Yi

2011-01-01

44

Hydraulics  

NSDL National Science Digital Library

These interactive learning objects, created by instructors from Fox Valley Technical College and other colleges in the Wisconsin Technical College program, focus on concepts that cover a broad-based electromechanical program. Here visitors will find learning objects in Hydraulics with over 25 lessons in Actuators, Relief Valves, Basic Concepts, and Directional Control Valves.

45

Activity Packing in FPGAs for Leakage Power Reduction Hassan Hassan Mohab Anis Antoine El Daher Mohamed Elmasry  

E-print Network

of the CMOS technology has precipitated an expo- nential increase in subthreshold leakage currents. ThereforeActivity Packing in FPGAs for Leakage Power Reduction Hassan Hassan Mohab Anis Antoine El Daher are proposed for leakage power mitigation. The first algorithm is a connection- based packing technique

Boyer, Edmond

46

Optimal design of power-split transmissions for hydraulic hybrid passenger vehicles  

Microsoft Academic Search

Hydraulic hybrid vehicles are inherently power dense. Power-split or hydro-mechanical transmissions (HMT) have advantages over series and parallel architectures. In this paper, an approach for optimizing the configuration and sizing of a hydraulic hybrid power-split transmission is proposed. Instead of considering each mechanical configuration consisting of combinations of gear ratios, a generalized kinematic relation is used to avoid redundant computation.

Kai Loon Cheong; Perry Y. Li; Thomas R. Chase

2011-01-01

47

Development and testing of a hydraulic powered diver operated rock drill and sea floor fasteners  

Microsoft Academic Search

The Civil Engineering Laboratory has developed a hand held diver operated rock drill. The drill is hydraulically powered thus eliminating the percussion and visibility problems associated with the underwater use of pneumatic rock drills. Capable of drilling holes up to 2-1\\/2 inches in diameter and 18 inches deep, the hydraulic rock drill has been used to install various seafloor fasteners

R. Brackett

1975-01-01

48

Haptic-enabled control of hydraulic manipulators applied to power line maintenance: Concept & implementation  

Microsoft Academic Search

In this paper, we present development of a scheme enabling a commercially available hydraulic robot to work with a haptic device performing live-line maintenance tasks. Presently live line maintenance is done manually by operators working in locations high above the ground and near high voltage power lines. Ground-level teleoperation of a hydraulic manipulator using a haptic device can potentially increase

K. Zarei-nia; N. Sepehri; T. Olson; W. Mueller

2010-01-01

49

Feasibility of hydraulic power recovery from waste energy in bio-gas scrubbing processes  

Microsoft Academic Search

This paper investigates the feasibility of recovering waste energy from typical bio-gas upgrading facilities by means of a hydraulic turbine, and presents analysis of different types of hydraulic power recovery turbines. A selection method and analysis is developed which can be applied to an existing process to determine the effectiveness and energy savings of such a system for its economic

Pradeep Bansal; Nick Marshall

2010-01-01

50

Dynamic Modeling of Hydraulic Power Steering System with Variable Ratio Rack and Pinion Gear  

Microsoft Academic Search

A comprehensive mathematical model of a typical hydraulic power steering system equipped with variable ratio rack and pinion gear is developed. The steering system's dynamic characteristics are investigated and its forced vibrations are compared with those obtained from a counterpart system with a constant ratio rack and pinion gear. The modeling details of the mechanism subsystem, hydraulic supply lines subsystem

Nong Zhang; Miao Wang

2005-01-01

51

NEUTRONIC AND THERMAL HYDRAULIC DESIGNS OF ANNULAR FUEL FOR HIGH POWER DENSITY BWRS  

E-print Network

As a promising new fuel for high power density light water reactors, the feasibility of using annular fuel for BWR services is explored from both thermal hydraulic and neutronic points of view. Keeping the bundle size ...

Morra, P.

52

A power pack based on organometallic perovskite solar cell and supercapacitor.  

PubMed

We present an investigation on a power pack combining a CH3NH3PbI3-based solar cell with a polypyrrole-based supercapacitor and evaluate its performance as an energy pack. The package achieved an energy storage efficiency of 10%, which is much higher than that of other systems combining a PV cell with a supercapacitor. We find a high output voltage of 1.45 V for the device under AM 1.5G illumination when the CH3NH3PbI3-based solar cell is connected in series with a polypyrrole-based supercapacitor. This system affords continuous output of electric power by using CH3NH3PbI3-based solar cell as an energy source mitigating transients caused by light intensity fluctuations or the diurnal cycle. PMID:25611128

Xu, Xiaobao; Li, Shaohui; Zhang, Hua; Shen, Yan; Zakeeruddin, Shaik M; Graetzel, Michael; Cheng, Yi-Bing; Wang, Mingkui

2015-02-24

53

GridPACK Toolkit for Developing Power Grid Simulations on High Performance Computing Platforms  

SciTech Connect

This paper describes the GridPACK™ framework, which is designed to help power grid engineers develop modeling software capable of running on todays high performance computers. The framework contains modules for setting up distributed power grid networks, assigning buses and branches with arbitrary behaviors to the network, creating distributed matrices and vectors, using parallel linear and non-linear solvers to solve algebraic equations, and mapping functionality to create matrices and vectors based on properties of the network. In addition, the framework contains additional functionality to support IO and to manage errors.

Palmer, Bruce J.; Perkins, William A.; Glass, Kevin A.; Chen, Yousu; Jin, Shuangshuang; Callahan, Charles D.

2013-11-30

54

Modern water hydraulics—the new energy-transmission technology in fluid power  

Microsoft Academic Search

With the increasing demand for an environmentally-friendly fluid medium in the fluid-power industries, recent advances in water hydraulics technology have sparked renewed interest in the application of water, instead of oil, as the energy-transmission medium. This paper introduces the history of water hydraulics and its present research. The advantages and disadvantages of water as an energy-transmission medium are discussed. A

G. H. Lim; P. S. K. Chua; Y. B. He

2003-01-01

55

Portable ammonia-borane-based H2 power-pack for unmanned aerial vehicles  

NASA Astrophysics Data System (ADS)

An advanced ammonia borane (AB)-based H2 power-pack is designed to continually drive an unmanned aerial vehicle (UAV) for 57 min using a 200-We polymer electrolyte membrane fuel cell (PEMFC). In a flight test with the UAV platform integrated with the developed power-pack, pure hydrogen with an average flow rate of 3.8 L(H2) min-1 is generated by autothermal H2-release from AB with tetraethylene glycol dimethylether (T4EGDE) as a promoter. During take-off, a hybridized power management system (PMS) consisting of the fuel cell and an auxiliary lithium-ion battery supplies 500 We at full power simultaneously, while the fuel cell alone provides 150-200 We and further recharges the auxiliary battery upon cruising. Gaseous byproducts identified by in situ Fourier transform infrared (FT-IR) spectroscopy during AB dehydrogenation are sequestrated using a mixed absorbent in an H2 purification system. In addition, a real-time monitoring system is employed to determine the remaining filter capacity of the purifier at a ground control system for rapidly responding unpredictable circumstances during flight. Separate experiments are conducted to screen potential materials and methods for enhancing filter capacity in the current H2 refining system. A prospective reactor concept for long-term fuel cell applications is proposed based on the results.

Seo, Jung-Eun; Kim, Yujong; Kim, Yongmin; Kim, Kibeom; Lee, Jin Hee; Lee, Dae Hyung; Kim, Yeongcheon; Shin, Seock Jae; Kim, Dong-Min; Kim, Sung-Yug; Kim, Taegyu; Yoon, Chang Won; Nam, Suk Woo

2014-05-01

56

Study of hydraulic power recovery from New Mexico water distribution systems  

Microsoft Academic Search

The results of a survey of New Mexico water distribution systems suitable for hydroelectric power development are reported. The objectives of the survey were to determine the potential for hydraulic power recovery from existing and planned water systems, to identify potential sites, and to study and recommend promising sites for further development. The survey found eleven sites in New Mexico

Schoenmackers

1984-01-01

57

Base-Bleed Effect on X-33 Aerospike Plume Induced Base-Heating Environment During Power-Pack Out  

NASA Technical Reports Server (NTRS)

A computational heat transfer methodology was developed to study the dual-engine linear aerospike plume induced base-heating environment during one power-pack out, in ascent flight. One power-pack out results in reduction of power levels for both engines. That, in turn, reduces the amount of base-bleed and changes the distribution of base-bleed on the two pillows. Hence, the concern of increased base-heating during power-pack out. The thermo-flowfield of the entire vehicle was computed. The computational methodology for the convective heating is based on a three-dimensional, finite-volume, viscous, chemically reacting, and pressure-based computational fluid dynamics formulation. The computational methodology for the radiative heating is based on a three-dimensional, finite-volume, and spectral-line-based weighted-sum-of-gray-gases absorption computational radiation heat transfer formulation. A separate radiation model was used for diagnostic purposes. The computational methodology was systematically benchmarked. In this study, near-base radiative heat fluxes were computed and they compared well with those measured from an installed linear aerospike engine tests. The base-heating environment of 18 trajectory points selected from three power-pack out ascent scenarios was computed and is presented here. The power-pack out condition has the most impact on convective base-heating when it happens early in flight. The some of its impact comes from the asymmetric and reduced base-bleed.

Wang, Tee-See; Droege, Alan; D'Agostino, Mark; Lee, Young-Ching; Williams, Robert

2003-01-01

58

Geodynamic Effects on the Dams in Cascade of the Sulak Hydraulic Power Systems  

Microsoft Academic Search

In view of the passage of the Federal statute, ”On the safety of hydraulic structures,” in 1999 and 2000 the Institute of Physics of the Earth of the Russian Academy of Sciences, the Dagestan Power Authority, and the Dagestan Scientific Center (Russian Academy of Sciences) carried out field investigations of geodynamic effects on the safety of the cascade of Sulak

A. N. Marchuk; A. R. Abakarov; M. G. Daniyalov; O. A. Asmanov; M. M. Mirzaliev; R. A. Levkovich

2001-01-01

59

Performance of a hydraulic air compressor for use in compressed air energy storage power systems  

Microsoft Academic Search

A fluid mechanical analysis of a hydraulic air compression system for Compressed Air Energy Storage application is presented. With this compression concept, air is charged into an underground reservoir, for later use in power generation, by entraining bubbles into a downward flow of water from a surface reservoir. Upon releasing the air in the underground reservoir, the water is pumped

J. A. Berghmans; F. W. Ahrens

1978-01-01

60

The hydraulic conductivity of chopped sorghum  

SciTech Connect

Hydraulic conductivity of water through chopped sweet sorghum at various packing densities and soaking times was measured using permeameters. Hydraulic conductivity decreased by two orders of magnitude as packing density increased from 400 to 897 kg/m/sup 3/. Soaking time had less effect on hydraulic conductivity, and the effect depended on packing density.

Custer, M.H.; Reddell, D.L.; Sweeten, J.M.

1987-01-01

61

An Integrated Power Pack of Dye-Sensitized Solar Cell and Li Battery Based on Double-Sided TiO2 Nanotube Arrays  

E-print Network

An Integrated Power Pack of Dye-Sensitized Solar Cell and Li Battery Based on Double-Sided TiO2 harvest and storage processes. This power pack incorporates a series-wound dye- sensitized solar cell material.11,15 Compared with other integrated solar power supplies,16,17 double-sided TiO2 NTs with large

Wang, Zhong L.

62

Design, simulation, and testing of a novel hydraulic power take-off system for the Pelamis wave energy converter  

Microsoft Academic Search

The economic viability of a wave energy converter depends largely on its power take-off system. Active control of the power take-off is necessary to maximise power capture across a range of sea-states and can also improve survivability. The high force, low speed regime of wave energy conversion makes it a suitable application for high-pressure hydraulics.This paper describes the hydraulic power

Ross Henderson

2006-01-01

63

On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy  

NASA Technical Reports Server (NTRS)

Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kilowatt tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated.A second portion of this DOE project involves sizing and costing a 15 megawatt tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation's 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one megawatt per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine's Western Passage. All would be connected to a high-pressure (20 megapascals, 2900 pounds per square inch) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, water-miscible fluid. Hydraulic adaptations to ORPC's cross-flow turbines are also discussed.For 15 megawatt of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimball, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

2012-01-01

64

On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy  

NASA Technical Reports Server (NTRS)

Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kW tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated. A second portion of this DOE project involves sizing and costing a 15 MW tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation s 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one MW per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine s Western Passage. All would be connected to a high-pressure (20 MPa, 2900 psi) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, watermiscible fluid. Hydraulic adaptations to ORPC s cross-flow turbines are also discussed. For 15 MW of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimbrall, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

2012-01-01

65

Vehicle having hydraulic and power steering systems using a single high pressure pump  

DOEpatents

A vehicle comprises a plurality of wheels attached to a vehicle housing. Also attached to the vehicle housing is a power steering system, including a fluid flow circuit, which is operably coupled to a number of the wheels. An internal combustion engine attached to the vehicle housing is connected to a hydraulically actuated system that includes a high pressure pump. An outlet of the high pressure pump is in fluid communication with the fluid flow circuit.

Bartley, Bradley E. (Manito, IL); Blass, James R. (Bloomington, IL); Gibson, Dennis H. (Chillicothe, IL)

2001-06-22

66

The role of filament-packing dynamics in powering amoeboid cell motility  

PubMed Central

Although several models have been proposed to account for how cytoskeleton polymerization drives protrusion in cell motility, the precise mechanism remains controversial. Here, we show that, in addition to force exerted directly against the membrane by growing filaments, the way elongating filaments pack also contributes to protrusion by generating an expansion of the cytoskeleton gel. Tomography shows that filament packing in the major sperm protein (MSP) -based nematode sperm-motility machinery resembles that observed with rigid rods. Maximum rod-packing density decreases dramatically as the rods lengthen. Therefore, as filaments elongate, the cytoskeleton gel expands to accommodate their packing less densely. This volume expansion combines with polymerization to drive protrusion. Consistent with this hypothesis, an engineered MSP mutant that generates shorter filaments shows higher filament-packing density and slower movement. PMID:18385381

Miao, Long; Vanderlinde, Orion; Liu, Jun; Grant, Richard P.; Wouterse, Alan; Shimabukuro, Katsuya; Philipse, Albert; Stewart, Murray; Roberts, Thomas M.

2008-01-01

67

Analysis of hydraulic power transduction in regenerative rotary shock absorbers as function of working fluid kinematic viscosity  

E-print Network

This investigation seeks to investigate the relationship of kinematic fluid viscosity to the effective power transduction seen by a hydraulic motor. Applications of this research specifically relate to energy recovery from ...

Avadhany, Shakeel N

2009-01-01

68

Dynamic Modeling of Hydraulic Power Steering System with Variable Ratio Rack and Pinion Gear  

NASA Astrophysics Data System (ADS)

A comprehensive mathematical model of a typical hydraulic power steering system equipped with variable ratio rack and pinion gear is developed. The steering system’s dynamic characteristics are investigated and its forced vibrations are compared with those obtained from a counterpart system with a constant ratio rack and pinion gear. The modeling details of the mechanism subsystem, hydraulic supply lines subsystem and the rotary spool valve subsystem are provided and included in the integrated steering system model. The numerical simulations are conducted to investigate the dynamics of the nonlinear parametric steering system. From the comparison between simulated results and the experimental ones, it is shown that the model accurately integrates the boost characteristics of the rotary spool valve which is the key component of hydraulic power steering system. The variable ratio rack-pinion gear behaviors significantly differently from its constant ratio counterpart does. It significantly affects not only the system natural frequencies but also reduces vibrations under constant rate and ramp torque steering inputs. The developed steering model produces valid predictions of the system’s behavior and therfore could assist engineers in the design and analysis of integrated steering systems.

Zhang, Nong; Wang, Miao

69

Hydraulic Car  

NSDL National Science Digital Library

In this activity, learners build cars using syringes and water-powered hydraulics. Learners construct the car frame out of cardboard and set up a hydraulic system to raise and lower the car. Use this project to introduce learners to incompressible fluids and Pascal's Principle.

Watsonville Environmental Science Workshop

2011-01-01

70

Numerical Hydraulic Study on Seawater Cooling System of Combined Cycle Power Plant  

NASA Astrophysics Data System (ADS)

As the rated flow and pressure increase in pumping facilities, a proper design against surges and severe cavitations in the pipeline system is required. Pressure surge due to start-up, shut-down process and operation failure causes the water hammer in upstream of the closing valve and the cavitational hammer in downstream of the valve. Typical cause of water hammer is the urgent closure of valves by breakdown of power supply and unexpected failure of pumps. The abrupt changes in the flow rate of the liquid results in high pressure surges in upstream of the valves, thus kinetic energy is transformed into potential energy which leads to the sudden increase of the pressure that is called as water hammer. Also, by the inertia, the liquid continues to flow downstream of the valve with initial speed. Accordingly, the pressure decreases and an expanding vapor bubble known as column separation are formed near the valve. In this research, the hydraulic study on the closed cooling water heat exchanger line, which is the one part of the power plant, is introduced. The whole power plant consists of 1,200 MW combined power plant and 220,000 m3/day desalination facility. Cooling water for the plant is supplied by sea water circulating system with a capacity of 29 m3/s. The primary focus is to verify the steady state hydraulic capacity of the system. The secondary is to quantify transient issues and solutions in the system. The circuit was modeled using a commercial software. The stable piping network was designed through the hydraulic studies using the simulation for the various scenarios.

Kim, J. Y.; Park, S. M.; Kim, J. H.; Kim, S. W.

2010-06-01

71

Development of a 7-function hydraulic underwater manipulator system  

Microsoft Academic Search

A 7-function underwater manipulator which is teleoperated by master-slave type is systemically developed. It is mainly comprised of master controller, connection box, slave arm, pressure compensator, valve pack and hydraulic power unit. The slave arm is operated by the master arm, which is fixed on the master controller used to operate, configure, and diagnose the manipulator system and is a

Jianjun Yao; Liquan Wang; Peng Jia; Zhuo Wang

2009-01-01

72

46 CFR 111.97-5 - Electric and hydraulic power supply.  

Code of Federal Regulations, 2012 CFR

...for each hydraulically operated watertight door system that uses a hydraulic system common to more than one watertight door must...operated watertight door system using an independent hydraulic system for each door operator must meet...

2012-10-01

73

46 CFR 111.97-5 - Electric and hydraulic power supply.  

Code of Federal Regulations, 2011 CFR

...for each hydraulically operated watertight door system that uses a hydraulic system common to more than one watertight door must...operated watertight door system using an independent hydraulic system for each door operator must meet...

2011-10-01

74

46 CFR 111.97-5 - Electric and hydraulic power supply.  

Code of Federal Regulations, 2014 CFR

...for each hydraulically operated watertight door system that uses a hydraulic system common to more than one watertight door must...operated watertight door system using an independent hydraulic system for each door operator must meet...

2014-10-01

75

46 CFR 111.97-5 - Electric and hydraulic power supply.  

Code of Federal Regulations, 2013 CFR

...for each hydraulically operated watertight door system that uses a hydraulic system common to more than one watertight door must...operated watertight door system using an independent hydraulic system for each door operator must meet...

2013-10-01

76

Thermal-hydraulics and safety analysis of sectored compact reactor for lunar surface power  

SciTech Connect

The liquid NaK-cooled, fast-neutron spectrum, Sectored Compact Reactor (SCoRe-N 5) concept has been developed at the Univ. of New Mexico for lunar surface power applications. It is loaded with highly enriched UN fuel pins in a triangular lattice, and nominally operates at exit and inlet coolant temperatures of 850 K and 900 K. This long-life reactor generates up to 1 MWth continuously for {>=} 20 years. To avoid a single point failure in reactor cooling, the core is divided into 6 sectors that are neutronically and thermally coupled, but hydraulically independent. This paper performs a 3-D the thermal-hydraulic analysis of SCoRe--N 5 at nominal operation temperatures and a power level of 1 MWth. In addition, the paper investigates the potential of continuing reactor operation at a lower power in the unlikely event that one sector in the core experiences a loss of coolant (LOC). Redesigning the core with a contiguous steel matrix enhances the cooling of the sector experiencing a LOC. Results show that with a core sector experiencing a LOC, SCORE-N 5 could continue operating safely at a reduced power of 166.6 kWth. (authors)

Schriener, T. M. [Inst. for Space and Nuclear Power Studies, Univ. of New Mexico, Albuquerque, NM (United States); Chemical and Nuclear Engineering Dept., Univ. of New Mexico, Albuquerque, NM (United States); El-Genk, M. S. [Inst. for Space and Nuclear Power Studies, Univ. of New Mexico, Albuquerque, NM (United States); Chemical and Nuclear Engineering Dept., Univ. of New Mexico, Albuquerque, NM (United States); Mechanical Engineering Dept., Univ. of New Mexico, Albuquerque, NM (United States)

2012-07-01

77

Asymmetric Base-Bleed Effect on Aerospike Plume-Induced Base-Heating Environment During Power-Pack Out  

NASA Technical Reports Server (NTRS)

A computational heat transfer design methodology was developed to study tbe dual-engine linear aerospike plume-induced base-heating environment during one power-pack out, in ascent flight. It includes a three-dimensional, finite volume, viscous, chemically reacting, and pressure-based computational fluid dynamics formulation, a special base-bleed boundary condition, and a three-dimensional, finite volume, and spectral-line-based weighted-sum-of-gray-gases absorption computational radiation heat transfer formulation. A separate radiation model was used for diagnostic purposes. The computational methodology was systematically benchmarked. in this study, near-base radiative heat fluxes were computed, and they compared well with those measured during static linear aerospike engine tests. The base-heating environment of 18 trajectory points secected from three power-pack out scenarios was computed. The computed asymmetric base-heating physics were analyzed. The power-pack out condition has the most impact on convective base heating when it happens early in flight. The soume of its impact comes from the asymmetric and reduced base bleed.

Wang, Ten-See; Droege, Alan; D'Agostino, Mark; Lee, Young-Ching; Williams, Robert

2003-01-01

78

Design of a hydraulic power take-off system for the wave energy device with an inverse pendulum  

NASA Astrophysics Data System (ADS)

This paper describes a dual-stroke acting hydraulic power take-off (PTO) system employed in the wave energy converter (WEC) with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth, fast rotation of an electrical generator. The design of the hydraulic PTO system and its control are critical to maximize the generated power. A time domain simulation study and the laboratory experiment of the full-scale beach test are presented. The results of the simulation and laboratory experiments including their comparison at full-scale are also presented, which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.

Zhang, Da-hai; Li, Wei; Zhao, Hai-tao; Bao, Jing-wei; Lin, Yong-gang

2014-04-01

79

Cavitation wear in hydraulic turbines at the Bratsk hydroelectric power plant  

Microsoft Academic Search

Conclusions  \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a A considerable cavitation wear of the runner blades at the Bratsk hydroelectric power plant occurred as the result of operating\\u000a the hydraulic turbines under conditions falling outside the design range and due to distortion of the blade profile caused\\u000a by electrode surfacing on a large scale carried out during repairs.\\u000a \\u000a \\u000a \\u000a \\u000a 2. \\u000a \\u000a The most effective method of reducing cavitation

I. S. Glukhov

1975-01-01

80

Numerical and field tests of hydraulic transients at Piva power plant  

NASA Astrophysics Data System (ADS)

In 2009, a sophisticated field investigation was undertaken and later, in 2011, numerical tests were completed, on all three turbine units at the Piva hydroelectric power plant. These tests were made in order to assist in making decisions about the necessary scope of the reconstruction and modernisation of the Piva hydroelectric power plant, a plant originally constructed in the mid-1970s. More specifically, the investigation included several hydraulic conditions including both the start-up and stopping of each unit, load rejection under governor control from different initial powers, as well as emergency shut-down. Numerical results were obtained using the method of characteristics in a representation that included the full flow system and the characteristics of each associated Francis turbine. The impact of load rejection and emergency shut-down on the penstock pressure and turbine speed changes are reported and numerical and experimental results are compared, showing close agreement.

Giljen, Z.

2014-12-01

81

Modeling the performance of the piston ring-pack with consideration of non-axisymmetric characteristics of the power cylinder system in internal combustion engines  

E-print Network

The performance of the piston ring-pack is directly associated with the friction, oil consumption, wear, and blow-by in internal combustion engines. Because of non-axisymmetric characteristics of the power cylinder system, ...

Liu, Liang, 1971-

2005-01-01

82

Valve Packing  

NASA Technical Reports Server (NTRS)

"S Glass" yarn was originally developed by NASA for high temperature space and aeronautical applications. When John Crane, Inc. required material that would withstand temperatures higher than 1,200 degrees Fahrenheit, they contacted Owens-Corning, which had developed a number of applications for the material. John Crane combines the yarn with other components to make Style 287-I packing. The product can be used in chemical processing operations, nuclear power stations, petroleum products, etc. Advantages include increased service life and reduced maintenance costs.

1992-01-01

83

Power function decay of hydraulic conductivity for a TOPMODEL-based infiltration routine  

NASA Astrophysics Data System (ADS)

TOPMODEL rainfall-runoff hydrologic concepts are based on soil saturation processes, where soil controls on hydrograph recession have been represented by linear, exponential, and power function decay with soil depth. Although these decay formulations have been incorporated into baseflow decay and topographic index computations, only the linear and exponential forms have been incorporated into infiltration subroutines. This study develops a power function formulation of the Green and Ampt infiltration equation for the case where the power n = 1 and 2. This new function was created to represent field measurements in the New York City, USA, Ward Pound Ridge drinking water supply area, and provide support for similar sites reported by other researchers. Derivation of the power-function-based Green and Ampt model begins with the Green and Ampt formulation used by Beven in deriving an exponential decay model. Differences between the linear, exponential, and power function infiltration scenarios are sensitive to the relative difference between rainfall rates and hydraulic conductivity. Using a low-frequency 30 min design storm with 4.8 cm h-1 rain, the n = 2 power function formulation allows for a faster decay of infiltration and more rapid generation of runoff. Infiltration excess runoff is rare in most forested watersheds, and advantages of the power function infiltration routine may primarily include replication of field-observed processes in urbanized areas and numerical consistency with power function decay of baseflow and topographic index distributions. Equation development is presented within a TOPMODEL-based Ward Pound Ridge rainfall-runoff simulation. Copyright

Wang, Jun; Endreny, Theodore A.; Hassett, James M.

2006-11-01

84

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

NASA Astrophysics Data System (ADS)

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.

Bucur, D. M.; Dunca, G.; Cervantes, M. J.; C?linoiu, C.; Isb??oiu, E. C.

2014-03-01

85

American Recovery & Reinvestment Act: Fuel Cell Hybrid Power Packs and Hydrogen Refueling for Lift Trucks  

SciTech Connect

HEB Grocery Company, Inc. (H-E-B) is a privately-held supermarket chain with 310 stores throughout Texas and northern Mexico. H-E-B converted 14 of its lift reach trucks to fuel cell power using Nuvera Fuel Cells’ PowerEdge™ units to verify the value proposition and environmental benefits associated with the technology. Issues associated with the increasing power requirements of the distribution center operation, along with high ambient temperature in the summer and other operating conditions (such as air quality and floor surface condition), surfaced opportunities for improving Nuvera’s PowerEdge fuel cell system design in high-throughput forklift environments. The project included on-site generation of hydrogen from a steam methane reformer, called PowerTap™ manufactured by Nuvera. The hydrogen was generated, compressed and stored in equipment located outside H-E-B’s facility, and provided to the forklifts by hydrogen dispensers located in high forklift traffic areas. The PowerEdge fuel cell units logged over 25,300 operating hours over the course of the two-year project period. The PowerTap hydrogen generator produced more than 11,100 kg of hydrogen over the same period. Hydrogen availability at the pump was 99.9%. H-E-B management has determined that fuel cell forklifts help alleviate several issues in its distribution centers, including truck operator downtime associated with battery changing, truck and battery maintenance costs, and reduction of grid electricity usage. Data collected from this initial installation demonstrated a 10% productivity improvement, which enabled H-E-B to make economic decisions on expanding the fleet of PowerEdge and PowerTap units in the fleet, which it plans to undertake upon successful demonstration of the new PowerEdge reach truck product. H-E-B has also expressed interst in other uses of hydrogen produced on site in the future, such as for APUs used in tractor trailers and refrigerated transport trucks in its fleet.

Block, Gus

2011-07-31

86

Control of Hydraulic Robots  

Microsoft Academic Search

\\u000a Hydraulic actuation has been widely used in industrial applications, attributed to its characteristic of having a large power\\u000a to mass ratio. Although this feature dramatically increases the operational capability of a hydraulically driven robot, the\\u000a inherent nonlinear dynamics associated with hydraulic cylinders substantially challenge the controller design. It is obvious\\u000a that the specific difficulties existed in the control of hydraulically

Wen-Hong Zhu

87

Evaluation of Army engine oils in hydraulic/power-transmission-system components. Final report, August 1984-November 1985  

SciTech Connect

The objective of the MACI Hydraulic System and Components Program is to perform technical evaluation and assessment of commerically available qualified and fielded Army engine oils and to determine if such oils can be used as hydraulic fluids in Army commercial construction equipment and material-handling equipment. Five Army specification engine lubricants--four MIL-L-2104D (one grade 10W, one grade 30, two grade 15W-40) and one MIL-L-46167, grade 0W-20--were evaluated using four critical component performance tests used by manufacturers. Data compiled from this and previous work have shown that the limiting factors of the Army engine oils used as hydraulic and multipurpose power transmission fluids appear to be (1) wet-brake chatter noise, (2) hydraulic-pump wear problems with some piston pumps using MIL-L-46167 Arctic engine oils at temperatures hotter-than-expected Arctic conditions, and possibly (3) copper corrosion. The prime area of concern is the wet-brake chatter noise.

Marbach, H.W.; Lestz, S.J.

1985-11-01

88

Performance Evaluation of IP Paging with Power Save Mechanism Ved Kafle, Sangheon Pack and Yanghee Choi  

E-print Network

foreign agents (RFAs). 2.1. Regional Registration To reduce signaling load in the IIPP, idle mobile nodes packet addressed to a dormant mobile node, it buffers the packet, and inquires the tracking agent about to the Mobile IP regional registration, the IIPP significantly reduces the average power consumption of a mobile

89

PowerPack: Energy Profiling and Analysis of High-Performance Systems and Applications  

E-print Network

and energy are primary concerns in modern high- performance computing system design. Operational costs. The need for high-performance comput- ing power efficiency is further amplified when considered]. To improve the energy efficiency of high-performance computing systems and applications, it is critical

90

Thermal-hydraulic analysis of cross-shaped spiral fuel in high power density BWRs  

E-print Network

Preliminary analysis of the cross-shaped spiral (CSS) fuel assembly suggests great thermal-hydraulic upside. According to computational models, the increase in rod surface area, combined with an increase in coolant turbulence ...

Conboy, Thomas M

2007-01-01

91

Treatment of screened dairy manure by upflow anaerobic fixed bed reactors packed with waste tyre rubber and a combination of waste tyre rubber and zeolite: effect of the hydraulic retention time.  

PubMed

Two laboratory-scale anaerobic fixed bed reactors were evaluated while treating dairy manure at upflow mode and semicontinuous feeding. One reactor was packed with a combination of waste tyre rubber and zeolite (R1) while the other had only waste tyre rubber as a microorganism immobilization support (R2). Effluent quality improved when the hydraulic retention time (HRT) increased from 1.0 to 5.5 days. Higher COD, BOD5, total and volatile solids removal efficiencies were always achieved in the reactor R1. No clogging was observed during the operation period. Methane yield was also a function of the HRT and of the type of support used, and was 12.5% and 40% higher in reactor R1 than in R2 for HRTs of 5.5 and 1.0 days, respectively. The results obtained demonstrated that this type of reactor is capable of operating with dairy manure at a HRT 5 times lower than that used in a conventional reactor. PMID:18280149

Umaña, Oscar; Nikolaeva, Svetlana; Sánchez, Enrique; Borja, Rafael; Raposo, Francisco

2008-10-01

92

Pack Saddle  

USGS Multimedia Gallery

This is a pack saddle used by Arnold Hague in the late 1800s. The wooden saddle has leather straps and a cinch used for the animal's comfort when carrying especially large loads. Pack saddles could be used to carry panniers or other large objects. Object ID: USGS-000014...

93

Technical specifications and norms for the design of hydraulic tunnels for hydroelectric power stations  

Microsoft Academic Search

Conclusions  \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a The construction plans for hydraulic tunnels and underground structures for hydroelectric stations require designing on the\\u000a basis of scientific investigations of the physicomechanical characteristics of rocks, carried out during excavation.\\u000a \\u000a \\u000a \\u000a \\u000a 2. \\u000a \\u000a For hydraulic tunnels and underground structures of all classes the calculation of rock pressure must be carried out on the\\u000a basis of scientific investigations. However, when carrying

A. G. Sarkisyan

1967-01-01

94

Frac pack technology still evolving  

SciTech Connect

Success of frac packs depends on candidate selection, treatment design, fluids and proppants, downhole tools, and treatment implementation. Current frac packing techniques have partially evolved from high-permeability stimulation in the Kuparuk field, Alaska. In the Gulf of Mexico (GOM), attempts were made as early as the mid-1960s to hydraulically fracture sands. These early treatments were not highly successful because of techniques, understanding of rock mechanical properties, and poor candidate selection. This article focuses primarily on frac packs in GOM wells, although this technique is also used in South America, Southeast Asia, Pakistan, Nigeria, Alaska, and Europe. Through mid-year 1995 in the GOM alone, there have been over 600 frac packs.

Ebinger, C.D. [Ely and Associates Inc., Houston, TX (United States)

1995-10-23

95

HYDRAULIC CONDUCTIVITY OF ESSENTIALLY SATURATED PEAT  

SciTech Connect

The Savannah River National Laboratory measured the hydraulic conductivity of peat samples using method ASTM D4511-00. Four samples of peat were packed into 73mm diameter plastic tubes and saturated from the bottom up with water. The columns were packed with Premier ProMoss III TBK peat to a dry density of approximately 0.16 gm/cc (10 lb/ft3). One column was packed using oven dried peat and the other 3 were packed using as delivered peat. The oven dried sample was the most difficult to saturate. All of the peat samples expanded during saturation resulting in a sample length (L) that was longer than when the sample was initially packed. Table 1 contains information related to the column packing. After saturation the hydraulic conductivity test was conducted using the apparatus shown in Figure 1. Three of the samples were tested at 2 different flow conductions, 1 high and 1 low. Table 2 and Figure 2 contain the results of the hydraulic conductivity testing. Each test was run for a minimum of 40 minutes to allow the test conditions to stabilize. The hydraulic conductivity at the end of each test is reported as the hydraulic conductivity for that test. The hydraulic conductivity of the 4 peat samples is 0.0052 {+-} 0.0009 cm/sec. This result compares well with the hydraulic conductivity measured in the pilot scale peat bed after approximately 2 months of operation. The similarity in results between the dry pack sample and moist pack samples shows the moisture content at the time of packing had a minimal effect on the hydraulic conductivity. Additionally, similarity between the results shows the test is reproducible. The hydraulic conductivity results are similar to those reported by other tests of peat samples reported in the literature.

Nichols, R

2008-02-27

96

HYDRAULIC POWER TRANSFER SYSTEMS. AGRICULTURAL MACHINERY--SERVICE OCCUPATIONS, MODULE NUMBER 9.  

ERIC Educational Resources Information Center

ONE OF A SERIES DESIGNED TO HELP TEACHERS PREPARE POSTSECONDARY-LEVEL STUDENTS FOR THE AGRICULTURAL MACHINERY SERVICE OCCUPATIONS AS PARTS MEN, MECHANICS, MECHANIC'S HELPERS, AND SERVICE SUPERVISORS, THIS GUIDE AIMS TO DEVELOP STUDENT COMPETENCY IN UNDERSTANDING BASIC HYDRAULICS AND ITS APPLICATION TO AGRICULTURAL MACHINERY. IT WAS DEVELOPED BY A…

Ohio State Univ., Columbus. Center for Vocational and Technical Education.

97

Novel Repair Technique for Life-Extension of Hydraulic Turbine Components in Hydroelectric Power Stations  

Microsoft Academic Search

A significant number of hydraulic turbines operated in Japan were installed in the first half of the 20th century. Today, aging degradation and flaws are observed in these turbine equipments. So far, Japanese engineers have applied NDI technology of Ultrasonic Testing (UT) to detect the flaws, and after empirical evaluation of the remaining life they decided an adequate moment to

Yoichi Hiramatsu; Jun Ishii; Kazuhiro Funato

2008-01-01

98

Relating relative hydraulic and electrical conductivity in the unsaturated zone  

NASA Astrophysics Data System (ADS)

Numerical modeling was used to generate pore-scale structures with different structural properties. They were partially saturated according to wetting and drainage regimes using morphological operations for a range of saturations. The hydraulic and electrical conductivities of the resulting partially saturated grain packs were numerically computed to produce relative hydraulic conductivity versus saturation and relative electrical conductivity versus saturation curves. The relative hydraulic conductivities were then compared to the relative electrical conductivities for the same saturations and it was found that relative hydraulic conductivity could be expressed as relative electrical conductivity to a power law exponent, ?. This exponent ? was not correlated to porosity, specific surface area, or tortuosity. It did change according to whether the soil was wetting or draining. However, a ? value of 2.1 reproduced relative hydraulic conductivity from relative electrical conductivity with little added error. The effects of surface conduction on the observed power law relationship due to either low fluid electrical conductivity or increased clay content were analyzed. The relationship was found to hold for fluid conductivities typical of groundwater and for clay content of less than 5% if the clays were layered perpendicular to electrical flow. The relationship breaks down for electrical flow parallel to clay layers, which makes the choice of electrode arrangement important in cases where clay may be present. This relationship can be used with secondary pressure or saturation data to characterize a soil's hydraulic conductivity curve.

Mawer, Chloe; Knight, Rosemary; Kitanidis, Peter K.

2015-01-01

99

Abstract--Small-scale hydraulics is ideal for powered human assistive devices including powered ankle foot orthoses because  

E-print Network

ankle foot orthoses because a large torque can be generated with an actuator that is small and light. A portable hydraulic ankle foot orthosis has been designed and is undergoing preliminary prototyping rehabilitation applications. I. INTRODUCTION A. Background An ankle-foot orthosis (AFO) is a device that assists

Durfee, William K.

100

Thermal-hydraulics Analysis of a Radioisotope-powered Mars Hopper Propulsion System  

SciTech Connect

Thermal-hydraulics analyses results produced using a combined suite of computational design and analysis codes are presented for the preliminary design of a concept Radioisotope Thermal Rocket (RTR) propulsion system. Modeling of the transient heating and steady state temperatures of the system is presented. Simulation results for propellant blow down during impulsive operation are also presented. The results from this study validate the feasibility of a practical thermally capacitive RTR propulsion system.

Robert C. O'Brien; Andrew C. Klein; William T. Taitano; Justice Gibson; Brian Myers; Steven D. Howe

2011-02-01

101

Degradation of Phosphate Ester Hydraulic Fluid in Power Station Turbines Investigated by a Three-Magnet Unilateral Magnet Array  

PubMed Central

A three-magnet array unilateral NMR sensor with a homogeneous sensitive spot was employed for assessing aging of the turbine oils used in two different power stations. The Carr-Purcell-Meiboom-Gill (CPMG) sequence and Inversion Recovery-prepared CPMG were employed for measuring the 1H-NMR transverse and longitudinal relaxation times of turbine oils with different service status. Two signal components with different lifetimes were obtained by processing the transverse relaxation curves with a numeric program based on the Inverse Laplace Transformation. The long lifetime components of the transverse relaxation time T2eff and longitudinal relaxation time T1 were chosen to monitor the hydraulic fluid aging. The results demonstrate that an increase of the service time of the turbine oils clearly results in a decrease of T2eff,long and T1,long. This indicates that the T2eff,long and T1,long relaxation times, obtained from the unilateral magnetic resonance measurements, can be applied as indices for degradation of the hydraulic fluid in power station turbines. PMID:24736132

Guo, Pan; He, Wei; García-Naranjo, Juan C.

2014-01-01

102

Degradation of phosphate ester hydraulic fluid in power station turbines investigated by a three-magnet unilateral magnet array.  

PubMed

A three-magnet array unilateral NMR sensor with a homogeneous sensitive spot was employed for assessing aging of the turbine oils used in two different power stations. The Carr-Purcell-Meiboom-Gill (CPMG) sequence and Inversion Recovery-prepared CPMG were employed for measuring the ¹H-NMR transverse and longitudinal relaxation times of turbine oils with different service status. Two signal components with different lifetimes were obtained by processing the transverse relaxation curves with a numeric program based on the Inverse Laplace Transformation. The long lifetime components of the transverse relaxation time T?eff and longitudinal relaxation time T? were chosen to monitor the hydraulic fluid aging. The results demonstrate that an increase of the service time of the turbine oils clearly results in a decrease of T?eff,long and T?,long. This indicates that the T?eff,long and T?,long relaxation times, obtained from the unilateral magnetic resonance measurements, can be applied as indices for degradation of the hydraulic fluid in power station turbines. PMID:24736132

Guo, Pan; He, Wei; García-Naranjo, Juan C

2014-01-01

103

Computerized valve packing program  

SciTech Connect

The purpose of this paper is to present the advantages of a computerized valve packing program and demonstrate Valveman{trademark}, a windows based, completely automated valve packing program. With deregulation of the power industry, it is evident to be more competitive, utilities are decreasing maintenance staffs. This challenges the personnel to be more productive. One area that is usually duplicated by various groups on a site is valve packing. So it is evident that a way of simplifying this process is very beneficial, not only from an efficiency stand point but also to a greater consistency and higher quality level. By establishing a consistency, it is easier to change personnel with a minimum learning curve. Also, the administration can get a complete picture of each job for better evaluation or to measure performance.

Taraszki, R. [Argo Packing Co., Aurora, IL (United States)

1996-11-01

104

Hydraulic resistance and convective heat transfer within independent power generation micro sources (IPM) channels  

NASA Astrophysics Data System (ADS)

The introduction of new structural materials and technologies contributes to the efficiency increase for the compact IPMs used in various branches of engineering. Use of a driving high-temperature (TIT600K), regenerative (the regeneration ratio is E>85%) micro gas turbine engine ?GTE, major components which are made of structural ceramics, allows not only to maintain the effective efficiency at ?e=26-30%, but, also, sharply reduce the material consumption rate for the micro source as a whole. Application of the laser prototyping technique to manufacture the air heater, which is a part of ?GTE, increases the IPM compactness. Miniaturization of the air heater, manufactured by the structural ceramics laser fusion, can significantly reduce the hydraulic diameter (dh<=1.0 mm) of the channels, designed to transport the working media inside it. Reducing dh leads to a significant increase in the hydraulic resistance of the micro channels. The associated increase in the energy consumption for ?GTE's own needs is compensated by increasing the TIT, E, and heat transfer coefficients in micro channels, and by eliminating the need in cooling for high temperature IPM components.

V, Sudarev A.; V, Sudarev B.; A, Suryaninov A.

2012-05-01

105

Novel Repair Technique for Life-Extension of Hydraulic Turbine Components in Hydroelectric Power Stations  

NASA Astrophysics Data System (ADS)

A significant number of hydraulic turbines operated in Japan were installed in the first half of the 20th century. Today, aging degradation and flaws are observed in these turbine equipments. So far, Japanese engineers have applied NDI technology of Ultrasonic Testing (UT) to detect the flaws, and after empirical evaluation of the remaining life they decided an adequate moment to replace the equipments. Since the replacement requires a large-scale field site works and high-cost, one of the solutions for life-extension of the equipments is introduction of repair services. We have been working in order to enhance the accuracy of results during the detection of flaws and flaws dimensioning, in particular focusing on the techniques of Tip-echo, TOFD and Phased-Array UT, accompanied by the conventional UT. These NDI methods made possible to recognize the entire image of surface and embedded flaws with complicated geometry. Then, we have developed an evaluation system of these flaws based on the theory of crack propagation, of the logic of crack growth driven by the stress-intensity factor of the crack tip front. The sophisticated evaluation system is constituted by a hand-made software and database of stress-intensity factor. Based on these elemental technologies, we propose a technique of repair welding to provide a life-extension of hydraulic turbine components.

Hiramatsu, Yoichi; Ishii, Jun; Funato, Kazuhiro

106

Particle-size distribution and packing fraction of geometric random packings  

Microsoft Academic Search

This paper addresses the geometric random packing and void fraction of polydisperse particles. It is demonstrated that the bimodal packing can be transformed into a continuous particle-size distribution of the power law type. It follows that a maximum packing fraction of particles is obtained when the exponent (distribution modulus) of the power law function is zero, which is to say,

H. J. H. Brouwers

2006-01-01

107

Effectiveness of hydraulic tomography: Sandbox experiments  

Microsoft Academic Search

Two sandbox experiments were conducted to evaluate the performance of a sequential geostatistical inverse approach for hydraulic tomography in characterizing aquifer heterogeneity. One sandbox was packed with layered sands to represent a stratified aquifer, while the other was packed with discontinuous sand bodies of different shapes and sizes to represent a more complex and realistic heterogeneous aquifer. Parallel to the

Shuyun Liu; T.-C. Jim Yeh; Ryan Gardiner

2002-01-01

108

46 CFR 58.30-10 - Hydraulic fluid.  

Code of Federal Regulations, 2012 CFR

...Fluid Power and Control Systems § 58.30-10 Hydraulic fluid. (a) The...b) The fluid used in hydraulic power transmission systems shall have a flashpoint...for operation of the hydraulic system through the entire...

2012-10-01

109

46 CFR 58.30-10 - Hydraulic fluid.  

Code of Federal Regulations, 2013 CFR

...Fluid Power and Control Systems § 58.30-10 Hydraulic fluid. (a) The...b) The fluid used in hydraulic power transmission systems shall have a flashpoint...for operation of the hydraulic system through the entire...

2013-10-01

110

46 CFR 58.30-10 - Hydraulic fluid.  

Code of Federal Regulations, 2011 CFR

...Fluid Power and Control Systems § 58.30-10 Hydraulic fluid. (a) The...b) The fluid used in hydraulic power transmission systems shall have a flashpoint...for operation of the hydraulic system through the entire...

2011-10-01

111

Hydraulic turbines: hydroelectric and tidal power systems. January, 1973-September, 1981 (citations from the BHRA Fluid Engineering data base). Report for Jan 73-Sep 81  

SciTech Connect

The hydrodynamics of adjustable blade hydraulic turbines are discussed as it applies to hydroelectric and tidal power generation. The adjustable blade concept is presented in terms of cavitation minimization as well as vibrational induced stresses on the blades. (Contains 91 citations fully indexed and including a title list.)

Not Available

1981-09-01

112

ENVIRONMENTAL HYDRAULICS  

EPA Science Inventory

The thermal, chemical, and biological quality of water in rivers, lakes, reservoirs, and near coastal areas is inseparable from a consideration of hydraulic engineering principles: therefore, the term environmental hydraulics. In this chapter we discuss the basic principles of w...

113

Hydraulic control for a power transmission with a manual range selector valve  

Microsoft Academic Search

This patent describes an improvement in power transmission controls having a plurality of shift control valve means including a forward valve means and a reverse valve means; forward-reverse direction control valve means; neutral valve means; regulator valve means; a plurality of solenoid means for controlling fluid pressure at control areas on the forward-reverse direction control valve means, the forward valve

1989-01-01

114

Basic Modeling and Simulation Tool for Analysis of Hydraulic Transients in Hydroelectric Power Plants  

Microsoft Academic Search

In this paper, the simulation system of a typical hydroelectric power plant was developed in a MATLAB\\/Simulink-based software environment, which has a high water head and a long penstock with upstream and downstream surge tanks and is equipped with a Francis turbine. With MATLAB\\/Simulink, the models of the proposed simulation system are all modularized and visualized, and can be reused

Hongqing Fang; Long Chen; Nkosinathi Dlakavu; Zuyi Shen

2008-01-01

115

Investigation of alternate power source for Space Shuttle Orbiter hydraulic system  

NASA Technical Reports Server (NTRS)

This investigation consists of a short-term feasibility study to determine whether or not an alternate electrical power source would trade favorably from a performance, reliability, safety, operation, and weight standpoint in replacing the current auxiliary power unit subsystems with its attendant components (water spray boiler, hydrazine fuel and tanks, feed and vent lines, controls, etc.), operating under current flight rules. Results of this feasibility study are used to develop recommendations for the next step (e.g., to determine if such an alternate electrical power source would show an advantage given that the current operational flight mode of the system could be modified in such a way as not to constrain the operational capability and safety of the vehicle). However, this next step is not within the scope of this investigation. This study does not include a cost analysis, nor does it include investigation of the integration aspects involved in such a trade, except in a qualitative sense for the determination of concept feasibility.

Simon, William E.; Young, Fred M.

1993-01-01

116

Hydraulics Lectures  

NSDL National Science Digital Library

This page from the WindTech TV project provides a link to lectures created by Jim Pytel for his hydraulics course at Columbia Gorge Community College. The lectures consist of live videos and screen capture style presentations and may be viewed free of charge. Clicking on the video link in the center of the page will lead users to a YouTube page with 31 lectures. Topics include hydraulics math, hydraulic safety, basic hydraulic schematics, viscosity, piston pumps, actuators, troubleshooting and more. These lectures would be extremely useful for technical and community college students taking a fundamental hydraulics course. Flash is required to view the videos.

Pytel, Jim

117

Portable Hydraulic Powerpack  

NASA Technical Reports Server (NTRS)

Rechargeable hydraulic powerpack functions as lightweight, compact source of mechanical energy. Self-contained hydraulic powerpack derives energy from solid chemical charge. Combustion of charge initiated by small hammer, and revolving feeder replaces charges expended. Combustion gases cool during expansion in turbine and not too hot for release to atmosphere. Unit has applications driving wheelchairs and operating drills, winches, and other equipment in remote areas. Also replaces electric motors and internal-combustion engines as source of power in explosive atmospheres.

Anderson, L. A.; Henry, R. L.; Fedor, O. H.; Owens, L. J.

1986-01-01

118

Hydrodynamic and mass transfer characteristic of a novel grid-structured plastic packing  

NASA Astrophysics Data System (ADS)

The hydraulic and mass transfer characteristic of a novel grid-structured plastic packing is presented. The geometry of this structured packings differ substantially from conventional corrugated structured packings resulting in an open structure which enables a free exchange of vapour and liquid also in horizontal direction. The hydraulic performance has been measured by air-water experiments in a 440 mm diameter column, the mass transfer characteristic has been determined with the absorption system ammonia-air-water. Is is shown that the grid-structured plastic packing is highly efficient, particularly in terms of the hydraulic capacity compared with random plastic packings. Beside this, the main advantage of the packing is the easy handling and installation as well as the low investment costs compared to the well-known conventional corrugated structured packings.

Lehner, Markus; Hoffmann, Karin; Geipel, Werner

2011-08-01

119

Variable-Displacement Hydraulic Drive Unit  

NASA Technical Reports Server (NTRS)

Hydraulic power controlled through multiple feedback loops. In hydraulic drive unit, power closely matched to demand, thereby saving energy. Hydraulic flow to and from motor adjusted by motor-control valve connected to wobbler. Wobbler angle determines motor-control-valve position, which in turn determines motor displacement. Concept applicable to machine tools, aircraft controls, and marine controls.

Lang, D. J.; Linton, D. J.; Markunas, A.

1986-01-01

120

Well packing system  

Microsoft Academic Search

This patent describes a packing structure and method of packing which can be used in the wellbore of injection wells for the recovery of heavy oils, shale oils, and tars, and in well shafts for in-situ coal gasification. The packing can also be used in the wellbore of gas and light oil production wells. The packing is used to provide

Drnevich

1990-01-01

121

Hydraulics. FOS: Fundamentals of Service.  

ERIC Educational Resources Information Center

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…

John Deere Co., Moline, IL.

122

PERFORMANCE OF AN AERIAL VARIABLE-RATE APPLICATION SYSTEM WITH A HYDRAULICALLY POWERED CHEMICAL PUMP AND SPRAY VALVE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The performance was evaluated for a variable-rate system that consisted of a SATLOC M3 with AirTrac software with WAAS corrected DGPS (5 Hz position update) and an AutoCal II automatic flow controller. This system was installed on an Air Tractor 402B equipped with an auxiliary hydraulic package tha...

123

Field test for verifying the capability of two high-powered hydraulic small robots for rescue operations  

Microsoft Academic Search

We developed rescue robots and tools that are driven by hydraulic actuators. They are small-sized, have simple mechanisms, and are suitable for heavy-duty rescue operations. This report shows the results of field tests carried out to verify the possibility of the two rescue robots we developed; we named them the Jack Robot and the Cutter Robot. We classified disaster situations

Mayuko Mori; Junichi Tanaka; Koichi Suzumori; Takefumi Kanda

2006-01-01

124

Israelachvili Packing factor  

NSDL National Science Digital Library

Israelachvili Packing factor. The geometry of associated structures depends upon "packing" properties of the molecule: the optimal area of the head group, a0, volume of the chain, V, and the critical length of the tether, lc.

Iacovella, Christopher R.

2006-08-02

125

Stochastic hydraulics  

NASA Astrophysics Data System (ADS)

The Fourth IAHR International Symposium on Stochastic Hydraulics, cosponsored by AGU and the American Society of Civil Engineers, will be held July 31-August 2, 1984, at Urbana, 111. About 40 papers selected from submitted abstracts will be presented in the symposium.Topics covered will include (but not be limited to) the following areas: risk and reliability analysis; safety of dams and other hydraulic structures; stochastic models; and stochastic processes of hydraulic and hydrologic phenomena such as turbulence, sediment transport, dispersion and diffusion, and random waves.The proceedings of the Second International Conference, held in Urbana, Illinois, in June 1981, are available from Water Resources Publications, Littleton, Colo., under the title, “Urban Stormwater Hydraulics and Hydrology” and “Urban Stormwater Quality, Management, and Planning.”

126

Almost Square Packing  

Microsoft Academic Search

\\u000a The almost square rectangle packing problem involves packing all rectangles with sizes 1 ×2 to n ×(n?+?1) (almost squares) into an enclosing rectangle of minimal area. This extends the previously studied square packing problem\\u000a by adding an additional degree of freedom for each rectangle, deciding in which orientation the item should be packed. We\\u000a show how to extend the model

Helmut Simonis; Barry O’Sullivan

2011-01-01

127

On Discrete Hyperbox Packing  

E-print Network

Bin packing is a very important and popular research area in the computer science field. Past work showed many good and real-world packing algorithms. How- ever, due to the complexity of the problem in multiple-dimensional bin packing, also called...

Li, Xiafeng

2010-01-14

128

In-line hydraulic dashpot  

NASA Astrophysics Data System (ADS)

An in-line hydraulic dashpot is disclosed that effectively decelerates the piston of a power cylinder by controllably choking off the oil which is providing pressure to the piston. The in-line hydraulic dashpot of the invention includes a valve spool member movable between an open and closed position along a fluid flow path that supplies oil to the power cylinder. An actuator rod is cooperative with the valve spool member and the piston shaft of the power cylinder to move tile valve spool member between its open and closed positions. The in-line hydraulic dashpot eliminates the clashing of mechanical parts and therewith eliminates the noise that would otherwise be generated thereby. The in-line hydraulic dashpot of the present invention makes possible the adaptation of a fixed stroke power cylinder to applications that call for a variable stroke length.

Moody, Paul E.

1992-10-01

129

AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT III, AUTOMATIC TRANSMISSIONS--HYDRAULICS (PART I).  

ERIC Educational Resources Information Center

THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO INTRODUCE BASIC HYDRAULIC PRINCIPLES AND PROVIDE AN UNDERSTANDING OF HYDRAULIC TRANSMISSIONS USED IN DIESEL POWERED VEHICLES. TOPICS ARE WHY USE HYDRAULICS, REVIEWING BASIC PHYSICS LAWS IN RELATION TO HYDRAULICS, UNDERSTANDING THE HYDRAULIC SYSTEM, AND DEVELOPING A BASIC HYDRAULIC SYSTEM. THE MODULE…

Human Engineering Inst., Cleveland, OH.

130

Orderly packed anodes for high-power lithium-ion batteries with super-long cycle life: rational design of MnCO3/large-area graphene composites.  

PubMed

MnCO3 particles uniformly distributed on large-area graphene form 2D composites whose large-area character enables them to self-assemble face-to-face into orderly packed electrodes. Such regular structures form continuous and efficient transport networks, leading to outstanding lithium storage with high capacity, ultralong cycle life, and excellent rate capability--all characteristics that are required for high-power lithium-ion batteries. PMID:25523603

Zhong, Yiren; Yang, Mei; Zhou, Xianlong; Luo, Yuting; Wei, Jinping; Zhou, Zhen

2015-02-01

131

Thermal hydraulic calculations to support increase in operating power in McClellen Nuclear Radiation Center(MNRC) TRIGA reactor.  

SciTech Connect

The RELAP5/Mod3.1 computer program has been used to successfully perform thermal-hydraulic analyses to support the Safety Analysis for increasing the MNRC reactor from 1.0 MW to 2.0 MW. The calculation results show the reactor to have operating margin for both the fuel temperature and critical heat flux limits. The calculated maximum fuel temperature of 705 C is well below the 750 C operating limit. The critical heat flux ratio was calculated to be 2.51.

Jensen, R. T.

1998-05-05

132

Leaf Pack Network  

NSDL National Science Digital Library

The Leaf Pack Network (LPN) is a network of teachers and students investigating their local stream ecosystems by participating in the leaf pack experiment, which involves creating an artificial leaf pack (dry leaves in a mesh bag), immersing it in a stream for 3-4 weeks, and examining it for signs of aquatic insects as indicators of stream health. Participating classrooms share their data through the internet. This activity highlights the connection between streamside forests and the ecology of rivers and streams.

133

Hydraulic Conductivity Measurements Barrow 2014  

DOE Data Explorer

Six individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, in May of 2013 as part of the Next Generation Ecosystem Experiment (NGEE). Each core was drilled from a different location at varying depths. A few days after drilling, the cores were stored in coolers packed with dry ice and flown to Lawrence Berkeley National Laboratory (LBNL) in Berkeley, CA. 3-dimensional images of the cores were constructed using a medical X-ray computed tomography (CT) scanner at 120kV. Hydraulic conductivity samples were extracted from these cores at LBNL Richmond Field Station in Richmond, CA, in February 2014 by cutting 5 to 8 inch segments using a chop saw. Samples were packed individually and stored at freezing temperatures to minimize any changes in structure or loss of ice content prior to analysis. Hydraulic conductivity was determined through falling head tests using a permeameter [ELE International, Model #: K-770B]. After approximately 12 hours of thaw, initial falling head tests were performed. Two to four measurements were collected on each sample and collection stopped when the applied head load exceeded 25% change from the original load. Analyses were performed between 2 to 3 times for each sample. The final hydraulic conductivity calculations were computed using methodology of Das et al., 1985.

Katie McKnight; Tim Kneafsey; Craig Ulrich; Jil Geller

134

Simulation of the perceptible feed-forward and feed-back properties of hydraulic power-steering systems on the vehicle’s handling behavior using simple physical models  

Microsoft Academic Search

Today, often complex component-oriented simulation models are used to study the influences of hydraulic power-steering systems on the vehicle’s handling properties. In these simulation models, we have a detailed description of the vehicle suspension components (links, joints, springs, etc.) extended by complex component simulation models of tires, bushings, and of course also by power-steering models. These power-steering models contain a

D. Ammon; M. Börner; J. Rauh

2006-01-01

135

Giant electrical fluctuations in metallic disordered packings  

NASA Astrophysics Data System (ADS)

We have experimentally studied granular arches through electrical measurements. The packing is composed of 2d metallic pentagons and is submitted to small taps. Large electrical fluctuations are observed and they are distributed along power laws. This indicates the presence of long-time memory effects even the packing density remains constant around a value ? = 0.72 ± 0.02. Large electrical fluctuations should be associated with the breaking/creation of granular arches.

Vandewalle, N.; Dorbolo, S.

136

Giant electrical fluctuations in metallic disordered packings  

Microsoft Academic Search

:   We have experimentally studied granular arches through electrical measurements. The packing is composed of 2d metallic pentagons and is submitted to small taps. Large electrical fluctuations are observed and they are distributed along\\u000a power laws. This indicates the presence of long-time memory effects even the packing density remains constant around a value\\u000a ? = 0.72?0.02. Large electrical fluctuations should

N. Vandewalle; S. Dorbolo

2001-01-01

137

THERMAL HYDRAULICS KEYWORDS: thermal hydraulics,  

E-print Network

-fluid modeling of nuclear reactor systems. Thermal-hydraulic analysis codes such as RELAP5-3D ~Ref. 1! and FLICA regions of the system. In fact, the CFD code FLUENT has previously been coupled to RELAP5-3D ~Refs. 3 parameter model of the thermally limiting core locations. However, these codes are not intended to pre- dict

Smith, Barton L.

138

Hydraulic Arm Challenge  

NSDL National Science Digital Library

Students design and build a mechanical arm that lifts and moves an empty 12-ounce soda can using hydraulics for power. Small design teams (1-2 students each) design and build a single axis for use in the completed mechanical arm. One team designs and builds the grasping hand, another team the lifting arm, and a third team the rotation base. The three groups must work to communicate effectively through written and verbal communication and sketches.

Center for Engineering Educational Outreach,

139

Design, modeling, fabrication and testing of a piezoelectric microvalve for high pressure, high frequency hydraulic applications  

E-print Network

A piezoelectrically-driven hydraulic amplification microvalve for use in high specific power hydraulic pumping applications was designed, fabricated, and experimentally characterized. High frequency, high force actuation ...

Roberts, David C. (David Christopher)

2002-01-01

140

Physico-chemical characterization of mortars as a tool in studying specific hydraulic components: application to the study of ancient Naxos aqueduct  

NASA Astrophysics Data System (ADS)

Mortars and plasters from the ancient aqueduct on the island of Naxos, Greece, were studied with regard to mineralogical and chemical composition, grain size distribution, raw materials and hydraulic properties, in order to assess their characteristics and design compatible repair mortars. The authentic materials contained lime, crushed-brick, siliceous and calcitic aggregates, in different proportions according to mortar type. Crushed-bricks fired at low temperatures and lightweight volcanic aggregates contained amorphous phases, which upon reaction with lime yielded hydraulic components capable of protecting the construction from the continuous presence of water. Hydraulic calcium silicate/aluminate hydrates, the proportions and the perfect packing of the raw materials, along with the diligent application justify the longevity and durability of the studied samples. The hydraulic properties of samples were pointed out through (a) the well-established CO2/H2O ratio derived from the thermogravimetric analysis and (b) by introducing two powerful indices issued from the chemical analysis, namely CaOhydr and soluble SiO2 hydr. These indices improved the clustering of hydraulic mortars and provided better correlation between mortars, plasters and their binders. By comparing grain size distribution and hydraulicity indices it was possible to distinguish among the construction phases. Based on this study, repair mortars were formulated by hydraulic lime, siliceous sand, calcareous and crushed-brick aggregates, with the optimal water content, ensuring optimum workability and compatible appearance with the authentic ones.

Maravelaki-Kalaitzaki, P.; Galanos, A.; Doganis, I.; Kallithrakas-Kontos, N.

2011-07-01

141

Search Strategies for Rectangle Packing  

Microsoft Academic Search

Abstract. Rectangle (square) packing problems,involve packing all squares with sizes 1 × 1 to n × n into the minimum area enclosing rectangle (respectively, square). Rectangle packing is a variant of an important problem,in a variety of real-world settings. For example, in electronic design automation, the packing of blocks into a circuit layout is essentially a rectangle packing problem. Rectangle

Helmut Simonis; Barry O’Sullivan

2008-01-01

142

Random packings of frictionless particles  

Microsoft Academic Search

We conduct numerical simulations of random packings of particles interacting via repulsive, finite-range potentials to study a special point at T=0. This point marks the onset of jamming with increasing packing fraction. Static granular packings must necessarily lie near this point because the particles are hard and it is difficult to compress packings to higher packing fraction. We find that

Corey O'Hern; Stephen Langer; Andrea Liu; Sidney Nagel

2002-01-01

143

Random Packings of Frictionless Particles  

Microsoft Academic Search

We conduct numerical simulations of random packings of frictionless particles at T = 0. The packing fraction where the pressure becomes nonzero is the same as the jamming threshold, where the static shear modulus becomes nonzero. The distribution of threshold packing fractions narrows, and its peak approaches random close packing as the system size increases. For packing fractions within the

Corey S. O'Hern; Stephen A. Langer; Andrea J. Liu; Sidney R. Nagel

2002-01-01

144

Flat Pack Toy Design  

ERIC Educational Resources Information Center

In this article, the author introduces the concept of flat pack toys. Flat pack toys are designed using a template on a single sheet of letter-sized card stock paper. Before being cut out and built into a three-dimensional toy, they are scanned into the computer and uploaded to a website. With the template accessible from the website, anyone with…

Hutcheson, Brian

2007-01-01

145

Relating Relative Hydraulic Conductivity and Electrical Conductivity in the Unsaturated Zone  

NASA Astrophysics Data System (ADS)

Monitoring flow in the unsaturated zone is an important task, especially for overseeing managed aquifer recharge, tracking contaminant transport, and optimizing agricultural operations. Geophysical data can provide in-situ unsaturated subsurface information with much higher temporal and spatial resolution over a larger areal extent than traditional hydrologic methods. The measurement of electrical conductivity is a geophysical technique of particular interest in the vadose zone because the geophysical parameter that is obtained is highly correlated with saturation. Changes in saturation can then be used to make qualitative inferences on the rate of fluid motion within the unsaturated zone. However, quantitative information on infiltration rates and unsaturated flow rates via saturation is typically hard to find and usually requires a cumbersome hydrologic inversion that cannot be done in real-time. In this work, we used numerical simulations to find a relationship that relates electrical conductivity not to saturation, but to relative hydraulic conductivity, which has been shown to be a useful proxy for direct estimation of infiltration and unsaturated flow rates even under transient conditions. We obtained this relationship through numerical modeling by generating pore-scale soil structures, partially saturating them through morphological operations according to both wetting and draining schemes and calculating their hydraulic and electrical conductivities at a range of saturations. We found that a power law relationship exists between relative hydraulic conductivity (hydraulic conductivity divided by saturated conductivity) and relative electrical conductivity for each of the sixteen tested media. The power law exponent in the relationship changes depending on whether the medium is being wetted or drained as would be expected as hysteresis is evident in both unsaturated hydraulic and electrical conductivity. Parameters that are typically seen to be related to both saturated conductivities, such as tortuosity, porosity and surface area to volume ratio were calculated for each sphere pack and plotted against the exponent. No correlation was seen between the exponent and these parameters for either the wetting or draining curves. However, the exponent was well constrained for the wetting curve to between 2.45 and 3 and the draining curve to between 1.6 and 2.2. The error introduced by using values within these bounds to estimate the hydraulic conductivity of any of the numerical soil packs using electrical conductivity was negligible, meaning that mean values of 2.75 and 1.8 could be used to estimate the hydraulic conductivity for any pack. These results are applicable to media with minimal surface conduction. We went on to analyze the effects of surface conduction via mineralogy and clay on the power law relationship between electrical and hydraulic conductivity via a number of approaches. We found that the power law relationship between hydraulic and electrical conductivity breaks down when clay content exceeds 5%. However, for media with less clay, use of the relationship with the mean values for exponents found for the clean medium results in less than ten percent error.

Mawer, C. M.; Knight, R. J.; Kitanidis, P. K.

2013-12-01

146

Graphitic packing removal tool  

DOEpatents

Graphitic packing removal tools for removal of the seal rings in one piece. he packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal.

Meyers, Kurt Edward (Avella, PA); Kolsun, George J. (Pittsburgh, PA)

1997-01-01

147

Hydraulic wind energy conversion system  

NASA Astrophysics Data System (ADS)

The purpose of this reseach 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 ft, 3/4 in. 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 7 ft, 1 in. I-D-flexhose.

1981-07-01

148

Hydraulic generator with free-piston engine  

Microsoft Academic Search

A hydraulic generator is disclosed with a free-piston engine and hydropneumatic return cushion and with an associated hydraulic-fluid pumping piston feeding a hydraulic accumulator intended to be charged between two detected levels of pressure. The generator includes a lock device for the free piston at the power-stroke dead center with voluntary control, and servo-control means for this lock device with

P. Bouthers; O. Breting

1983-01-01

149

Packing Peanut Properties  

NSDL National Science Digital Library

Students work with various types of packing peanuts to investigate states of matter and chemical and physical changes. One of the activities involves making slime. The activities can easily be modified for students with learning disabilities.

Dori Hall

2002-02-02

150

Packing paths in digraphs  

E-print Network

f ~P1g, or f ~P1; ~P2g, the G-packing problem is NP-complete. When G = f ~P1g, the G-packing problem is simply the matching problem. We treat in detail the one remaining case, G = f ~P1; ~P2g. We give in this case a polynomial algorithm for the packing problem. We also give the following positive results: a Berge type augmenting configuration theorem, a min-max characterization, and a reduction to bipartite matching. These results apply also to packings by the family G consisting of all directed paths and cycles. We also explore weighted variants of the problem and include a polyhedral analysis.

Richard C. Brewster; Pavol Hell; Sarah H. Pantel; Romeo Rizzi; Anders Yeo

151

Nasal packing and stenting  

PubMed Central

Nasal packs are indispensable in ENT practice. This study reviews current indications, effectiveness and risks of nasal packs and stents. In endoscopic surgery, nasal packs should always have smooth surfaces to minimize mucosal damage, improve wound healing and increase patient comfort. Functional endoscopic endonasal sinus surgery allows the use of modern nasal packs, since pressure is no longer required. So called hemostatic/resorbable materials are a first step in this direction. However, they may lead to adhesions and foreign body reactions in mucosal membranes. Simple occlusion is an effective method for creating a moist milieu for improved wound healing and avoiding dryness. Stenting of the frontal sinus is recommended if surgery fails to produce a wide, physiologically shaped drainage path that is sufficiently covered by intact tissue. PMID:22073095

Weber, Rainer K.

2011-01-01

152

Fully Dynamic Bin Packing  

NASA Astrophysics Data System (ADS)

Classic bin packing seeks to pack a given set of items of possibly varying sizes into a minimum number of identical sized bins. A number of approximation algorithms have been proposed for this NP-hard problem for both the on-line and off-line cases. In this chapter we discuss fully dynamic bin packing, where items may arrive (Insert) and depart (Delete) dynamically. In accordance with standard practice for fully dynamic algorithms, it is assumed that the packing may be arbitrarily rearranged to accommodate arriving and departing items. The goal is to maintain an approximately optimal solution of provably high quality in a total amount of time comparable to that used by an off-line algorithm delivering a solution of the same quality.

Ivkovi?, Zoran; Lloyd, Errol L.

153

Sphere packings III  

Microsoft Academic Search

This is the fifth in a series of papers giving a proof of the Kepler conjecture, which asserts that the density of a packing of congruent spheres in three dimensions is never greater than $\\\\pi\\/\\\\sqrt{18}\\\\approx 0.74048...$. This is the oldest problem in discrete geometry and is an important part of Hilbert's 18th problem. An example of a packing achieving this

Thomas C. Hales

1998-01-01

154

Hydraulic fracturing-1  

SciTech Connect

This book contains papers on hydraulic fracturing. Topics covered include: An overview of recent advances in hydraulic fracturing technology; Containment of massive hydraulic fracture; and Fracturing with a high-strength proppant.

Not Available

1990-01-01

155

Flow Rate Dependence of Soil Hydraulic Characteristics D. Wildenschild,* J. W. Hopmans, J. Simunek  

E-print Network

Flow Rate Dependence of Soil Hydraulic Characteristics D. Wildenschild,* J. W. Hopmans, J. Simunek ABSTRACT referred to a study by Harris and Morrow (1964), who studied pendular rings in packs of relatively

Wildenschild, Dorthe

156

Development, setup and testing of a dynamic hydraulic fracture conductivity apparatus  

E-print Network

One of the most critical parameters in the success of a hydraulic fracturing treatment is to have sufficiently high fracture conductivity. Unbroken polymers can cause permeability impairment in the proppant pack and/or in the matrix along...

Pongthunya, Potcharaporn

2009-06-02

157

Numerical Analysis of Elastohydrodynamic Contacts Using Power-law Lubricant With Special Reference to Water-based Hydraulic Fluids  

Microsoft Academic Search

A numerical solution of the elastohydrodynamic lubrication problem for pure rolling with non-Newtonian lubricants is outlined. The non-Newtonian rheological model used is a modified power-law, ? = K · ?. At low shear rate, ? < ?b the lubricant is Newtonian, but when ? > ?b the lubricant becomes non-Newtonian, ? = K · ?. At high shear rate (?

Ove Isaksson

1986-01-01

158

Downhole hydraulic seismic generator  

SciTech Connect

This patent describes a downhole seismic source for operation within a borehole to produce seismic energy waves through surrounding earth strata. It includes an elongated housing adapted for lowering into the borehole by a cable means; a hydraulic oscillator means carried by the housing for producing seismic vibrations in the housing; a hydraulic pressure source carried by the housing for providing a flow of high pressure hydraulic fluid, comprising a pump means for recycling the hydraulic fluid and for recharging the downhole seismic source and an electric motor for driving the pump means, the hydraulic pressure source further comprising a low pressure fluid accumulator which receives spent hydraulic fluid from the hydraulic oscillator means and from the clamp valve means and outputs hydraulic fluid to any pump means which outputs a high pressure hydraulic fluid, a heat exchanger means for receiving the high pressure fluid from the pump means and for dissipating heat produced by the pump means in the hydraulic fluid, and a high pressure accumulator for receiving the high pressure hydraulic fluid from the heat exchanger means and for providing the high pressure fluid as an output to an electro-hydraulic servovalve means, whereby the downhole seismic source is recharged for future operation; an electro-hydraulic servovalve means operably connected between the hydraulic pressure source and the hydraulic oscillator means for controlling the flow of high pressure hydraulic fluid from the hydraulic pressure source into the hydraulic oscillator means which thus produces the seismic vibrations; and a clamping means.

Gregory, D.L.; Hardee, H.C.; Smallwood, D.O.

1992-05-19

159

Water hydraulic actuators for ITER maintenance devices  

Microsoft Academic Search

The characteristic advantages of hydraulics (high power density, simple construction and reliability) together with the characteristics of water as the pressure medium (fire and environmentally safe, chemically neutral, not activated nor affected by radiation) are highlighted in critical applications such as remote handling operations in international thermonuclear experimental reactor (ITER). However, lack of commercial selection of water hydraulic components, common

Mikko Siuko; M. Pitkäaho; A. Raneda; J. Poutanen; J. Tammisto; J. Palmer; M. Vilenius

2003-01-01

160

Random Packings of Frictionless Particles  

Microsoft Academic Search

We study random packings of frictionless particles at T=0.\\u000a The packing fraction where the pressure becomes nonzero is the same as the\\u000ajamming threshold, where the static shear modulus becomes nonzero. The\\u000adistribution of threshold packing fractions narrows and its peak approaches\\u000arandom close-packing as the system size increases. For packing fractions within\\u000athe peak, there is no self-averaging, leading

Corey S. O'Hern; Stephen A. Langer; Andrea J. Liu; R. Nagel

2002-01-01

161

46 CFR 58.30-10 - Hydraulic fluid.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Hydraulic fluid. 58.30-10 Section 58...and Control Systems § 58.30-10 Hydraulic fluid. (a) The requirements...inspection. (b) The fluid used in hydraulic power transmission systems shall...

2010-10-01

162

Bin Packing - Optimization Online  

E-print Network

However, the bin packing problem takes a list of items as input, while the cutting stock problem ..... For testing this model, we have done the following experiment. For each ..... Note that the average run time (tlp + tip) is less than 2 seconds.

Filipe Brandao

2012-04-13

163

Economics Action Pack.  

ERIC Educational Resources Information Center

One of five McDonald's Action Packs, this learning package introduces intermediate grade students to basic economic concepts. The fourteen activities include the topics of consumption (4 activities), production (5), the market system (3), a pretest, and a posttest. Specific titles under consumption include The Wonderful Treasure Tree (introduction…

McDonald's Corp., Oak Brook, IL.

164

Professional Training Information Pack  

E-print Network

in the year, to check how the training is progressing. You will be regarded as an employee of the hostIntending Professional Training Students Year 2 Information Pack #12;- 1 - Applying for a Professional Training Placement To be allowed to do the Professional Training you must have enrolled on one

Davies, Christopher

165

Crystallization of pentagon packings  

Microsoft Academic Search

We present an experiment of densification of a 2D horizontal assembly made of regular pentagons. The annealing leads to a dense crystalline arrangement with quasisixfold symmetry in spite of the geometrical characteristics of the grains and of the a priori short-range correlation length in the packing. This configuration yields the maximum average number of side to side contacts between the

Y. Limon Duparcmeur; A. Gervois; J. P. Troadec

1995-01-01

166

Packing Them In.  

ERIC Educational Resources Information Center

This activity involves students investigating the mathematics of packaging and exploring various concepts in geometry, including area and the Pythagorean theorem. Mathematics comes out of the discussion of packaging cans into six-packs and focuses on the cost-effectiveness of the horizontal storage area used. Students learn how knowledge of…

Carter, Claudia

1997-01-01

167

Analysis of agglomerated packings  

Microsoft Academic Search

Results of computer simulation of the packing of particles in compacts from agglomerated powders are presented. The effect of the characteristics of agglomerated powders, such as the number of particles in the agglomerates, the size distribution of agglomerates, and the volume share of the fine fraction (individual particles) on the factors that determine the sinterability of compacts, i.e., the density,

A. V. Galakhov; E. V. Tsibailo; G. A. Fomina; B. S. Mitin

1995-01-01

168

Nutrition Action Pack.  

ERIC Educational Resources Information Center

One of five McDonald's Action Packs, these instructional materials integrate elementary school-level nutrition education into other disciplines--biology, sociology, physiology, mathematics, and art. Contents include four units consisting of twelve activities. Unit 1, Why You Need Food, is a self-examination of what is needed for growth, health,…

Sockut, Joanne; Stumpe, Stephanie

169

Hydraulic set and straight pull release well packer  

Microsoft Academic Search

A well packer is described which is adapted to be set in a conduit disposed in a well bore having initially retracted packing seal means and initially retracted slip means which are set by opposing acting hydraulically actuated pistons. A single one-way clutch is connected between the pistons allowing simultaneous movement of the pistons for setting and holding the packer

Garner

1981-01-01

170

Packed Bed Combustion: An Overview  

E-print Network

Packed Bed Combustion: An Overview William Hallett Dept. of Mechanical Engineering Université d'Ottawa - University of Ottawa #12;Packed Bed Combustion - University of Ottawa - CICS 2005 Introduction air fuel feedproducts xbed grate Packed Bed Combustion: fairly large particles of solid fuel on a grate, air supplied

Hallett, William L.H.

171

Simultaneous hydraulic fracturing  

SciTech Connect

A process is described for simultaneous hydraulic fracturing of a hydrocarbonaceous fluid-bearing formation comprising: (a) determining a hydraulic pressure necessary to fracture the formation from at least two wells which penetrate the formation; (b) injecting a hydraulic fracturing fluid into both wells under the determined hydraulic pressure; and (c) applying simultaneously the determined hydraulic pressure to the hydraulic fluid contained in both wells which pressure is sufficient to fracture the formation thereby causing a fracture to be propagated from each well in a curved manner sufficient to intersect at least one natural hydrocarbonaceous fluid-bearing fracture.

Uhri, D.C.

1989-05-16

172

7 CFR 51.310 - Packing requirements.  

Code of Federal Regulations, 2011 CFR

...United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons...3 2 “Fairly tight” means that apples are of the proper size for...

2011-01-01

173

7 CFR 51.310 - Packing requirements.  

Code of Federal Regulations, 2014 CFR

...United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons...3 2 “Fairly tight” means that apples are of the proper size for...

2014-01-01

174

7 CFR 51.310 - Packing requirements.  

Code of Federal Regulations, 2010 CFR

...United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons...3 2 “Fairly tight” means that apples are of the proper size for...

2010-01-01

175

7 CFR 51.310 - Packing requirements.  

Code of Federal Regulations, 2013 CFR

...United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons...3 2 “Fairly tight” means that apples are of the proper size for...

2013-01-01

176

7 CFR 51.310 - Packing requirements.  

Code of Federal Regulations, 2012 CFR

...United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons...3 2 “Fairly tight” means that apples are of the proper size for...

2012-01-01

177

Local anisotropy in globally isotropic granular packings  

NASA Astrophysics Data System (ADS)

We study local stresses and elastic moduli defined at various coarse-graining scales, R, and volume fractions, ?, in a two dimensional (2D) mixture of frictionless granular particle packings. We measure the average deviatoric stress normalized by pressure, ?/p, and normalized anisotropic component of the shear modulus, ??/?, as a function of R. As the packings are prepared isotropically, both ?/p and ??/? vanish at large R. However, in local regions, where single force chains dominate, the response can be quite anisotropic. We show that ?/p exhibits two power-law regimes in R with a cross-over that is only weakly dependent on ?. In contrast, ??/?, behaves like a pure power law up to R˜640D (where D is the characteristic particle diameter) at all ?.

Karimi, Kamran; Maloney, Craig

2011-03-01

178

Granular packings and fault zones  

PubMed

The failure of a two-dimensional packing of elastic grains is analyzed using a numerical model. The packing fails through formation of shear bands or faults. During failure there is a separation of the system into two grain-packing states. In a shear band, local "rotating bearings" are spontaneously formed. The bearing state is favored in a shear band because it has a low stiffness against shearing. The "seismic activity" distribution in the packing has the same characteristics as that of the earthquake distribution in tectonic faults. The directions of the principal stresses in a bearing are reminiscent of those found at the San Andreas Fault. PMID:11017335

Astrom; Herrmann; Timonen

2000-01-24

179

Electrically recharged battery employing a packed/spouted bed metal particle electrode  

DOEpatents

A secondary metal air cell, employing a spouted/packed metal particle bed and an air electrode, is described. More specifically a zinc air cell well suited for use in electric vehicles which is capable of being either electrically or hydraulically recharged. 5 figs.

Siu, S.C.; Evans, J.W.; Salas-Morales, J.

1995-08-15

180

Packing Products: Polystyrene vs. Cornstarch  

ERIC Educational Resources Information Center

Packing materials such as polystyrene take thousands of years to decompose, whereas packing peanuts made from cornstarch, which some companies are now using, can serve the same purpose, but dissolve in water. The author illustrates this point to her class one rainy day using the sculptures students made from polystyrene and with the cornstarch…

Starr, Suzanne

2009-01-01

181

Response of Jammed Ellipsoid Packings  

Microsoft Academic Search

We investigate the nature of the jamming transition for packings of spheroids by examining the elastic moduli as a function of the aspect ratio of the particles ? and the compression. Irrespective of the particle aspect ratio, both shear modulus G and bulk modulus B show the same scaling as a function of compression as is found for packings of

Zorana Zeravcic; Andrea Liu; Sidney Nagel

2011-01-01

182

Hydraulic fracture design optimization  

SciTech Connect

This research and development investigation, sponsored by US DOE and the oil and gas industry, extends previously developed hydraulic fracture geometry models and applied energy related characteristic time concepts towards the optimal design and control of hydraulic fracture geometries. The primary objective of this program is to develop rational criteria, by examining the associated energy rate components during the hydraulic fracture evolution, for the formulation of stimulation treatment design along with real-time fracture configuration interpretation and control.

Lee, Tae-Soo; Advani, S.H.

1992-06-01

183

Hydraulic fracture design optimization  

SciTech Connect

This research and development investigation, sponsored by US DOE and the oil and gas industry, extends previously developed hydraulic fracture geometry models and applied energy related characteristic time concepts towards the optimal design and control of hydraulic fracture geometries. The primary objective of this program is to develop rational criteria, by examining the associated energy rate components during the hydraulic fracture evolution, for the formulation of stimulation treatment design along with real-time fracture configuration interpretation and control.

Lee, Tae-Soo; Advani, S.H.

1992-01-01

184

Packed Bed Reactor Technology for Chemical-Looping Combustion  

Microsoft Academic Search

Chemical-looping combustion (CLC) has emerged as an alternative for conventional power production processes to intrinsically integrate power production and CO2 capture. In this work a new reactor concept for CLC is proposed, based on dynamically operated packed bed reactors. With analytical expressions validated with a more detailed numerical model, it is demonstrated that a constant, very high temperature air stream

Sander Noorman; Sint Annaland van Martin; Hans Kuipers; N. A. M. Asbroek; P. H. M. Feron

2007-01-01

185

PackBot: a versatile platform for military robotics  

NASA Astrophysics Data System (ADS)

The iRobot PackBot is a combat-tested, man-portable UGV that has been deployed in Afghanistan and Iraq. The PackBot is also a versatile platform for mobile robotics research and development that supports a wide range of payloads suitable for many different mission types. In this paper, we describe four R&D projects that developed experimental payloads and software using the PackBot platform. CHARS was a rapid development project to develop a chemical/radiation sensor for the PackBot. We developed the CHARS payload in six weeks and deployed it to Iraq to search for chemical and nuclear weapons. Griffon was a research project to develop a flying PackBot that combined the capabilities of a UGV and a UAV. We developed a Griffon prototype equipped with a steerable parafoil and gasoline-powered motor, and we completed successful flight tests including remote-controlled launch, ascent, cruising, descent, and landing. Valkyrie is an ongoing research and development project to develop a PackBot payload that will assist medics in retrieving casualties from the battlefield. Wayfarer is an applied research project to develop autonomous urban navigation capabilities for the PackBot using laser, stereo vision, GPS, and INS sensors.

Yamauchi, Brian M.

2004-09-01

186

Thermally Actuated Hydraulic Pumps  

NASA Technical Reports Server (NTRS)

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 vessels. Heretofore, electrically actuated hydraulic pumps have been used for this purpose. By eliminating the demand for electrical energy for pumping, the use of the thermally actuated hydraulic pumps could prolong the intervals between battery charges, thus making it possible to greatly increase the durations of undersea exploratory missions.

Jones, Jack; Ross, Ronald; Chao, Yi

2008-01-01

187

Packed Bed Reactor Experiment - Duration: 17 seconds.  

NASA Video Gallery

The purpose of the Packed Bed Reactor Experiment in low gravity is to determine how a mixture of gas and liquid flows through a packed bed in reduced gravity. A packed bed consists of a metal pipe ...

188

7 CFR 51.3055 - Standard pack.  

Code of Federal Regulations, 2013 CFR

... United States Standards for Florida Avocados Standard Pack § 51.3055 Standard pack. (a) The avocados shall be packed in accordance with...fruit in the container. Size of the avocados may be specified by count....

2013-01-01

189

7 CFR 51.3055 - Standard pack.  

Code of Federal Regulations, 2014 CFR

... United States Standards for Florida Avocados Standard Pack § 51.3055 Standard pack. (a) The avocados shall be packed in accordance with...fruit in the container. Size of the avocados may be specified by count....

2014-01-01

190

7 CFR 51.3055 - Standard pack.  

Code of Federal Regulations, 2011 CFR

... United States Standards for Florida Avocados Standard Pack § 51.3055 Standard pack. (a) The avocados shall be packed in accordance with...fruit in the container. Size of the avocados may be specified by count....

2011-01-01

191

7 CFR 51.3055 - Standard pack.  

Code of Federal Regulations, 2010 CFR

... United States Standards for Florida Avocados Standard Pack § 51.3055 Standard pack. (a) The avocados shall be packed in accordance with...fruit in the container. Size of the avocados may be specified by count....

2010-01-01

192

7 CFR 51.3055 - Standard pack.  

Code of Federal Regulations, 2012 CFR

... United States Standards for Florida Avocados Standard Pack § 51.3055 Standard pack. (a) The avocados shall be packed in accordance with...fruit in the container. Size of the avocados may be specified by count....

2012-01-01

193

Leaf Hydraulics Lawren Sack1  

E-print Network

Leaf Hydraulics Lawren Sack1 and N. Michele Holbrook2 1 Department of Botany, University of Hawai influence rates of transpiration and photosynthesis. Leaf hydraulic conductance (Kleaf) varies more than 65. #12;Contents INTRODUCTION. . . . . . . . . . . . . . . . . 362 LEAF HYDRAULIC CONDUCTANCE

Holbrook, N. Michele

194

Valve stem and packing assembly  

DOEpatents

A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

Wordin, John J. (Bingham County, ID)

1991-01-01

195

Valve stem and packing assembly  

DOEpatents

A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

Wordin, J.J.

1991-09-03

196

Environmentally adapted hydraulic oils  

Microsoft Academic Search

A comparison has been carried out between one mineral based hydraulic oil and three environmentally adapted hydraulic oils. Two of these are semi-synthetic oils, i.e. mixtures of vegetable base oil and synthetic esters, and the last is based on synthetic esters only. Technical properties such as viscosity, pour point etc., and chemical properties such as phosphorus and sulphur content etc.

Elisabet Kassfeldt; Göran Dave

1997-01-01

197

Bud development and hydraulics  

PubMed Central

The distal zone of one-year-old apple (Malus domestica) shoots was studied on five cultivars for bud size and composition (number of appendages) and hydraulic conductance before bud burst. Our hypothesis was that bud development was related to hydraulic conductance of the sap pathway to the bud independent of an acrotonic (proximal vs. distal) effect. Bud size and composition, and hydraulic conductance, were highly variable for all cultivars. A positive correlation was demonstrated between both the number of cataphylls and green-leaf primordia and hydraulic conductance. Cultivar and bud size affected the intercept of these relationships more than the slope suggesting similar scaling between these variables but different hydraulic efficiencies. A great proportion of small buds were also characterized by null values of hydraulic conductance. Our study suggests that hydraulically mediated competitions exist between adjacent buds within a same branching zone prefiguring the variability of lateral types in the following growing season. It is hypothesized that this developmental patterning is driven by hydraulic characteristics of the whole-metamer, including the subtending leaf, during bud development. PMID:19704779

Cochard, Hervé

2008-01-01

198

Enabling Microliquid Chromatography by Microbead Packing of Microchannels  

NASA Technical Reports Server (NTRS)

The microbead packing is the critical element required in the success of on-chip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and low-power element to separate amino acids and their chiral partners efficiently to understand better the origin of life. In order to densely pack microbeads into the microchannels, a liquid slurry of microbeads was created. Microbeads were extracted from a commercially available high-performance liquid chromatography column. The silica beads extracted were 5 microns in diameter, and had surface coating of phenyl-hexyl. These microbeads were mixed with a 200- proof ethanol solution to create a microbead slurry with the right viscosity for packing. A microfilter is placed at the outlet via of the microchannel and the slurry is injected, then withdrawn across a filter using modified syringes. After each injection, the channel is flushed with ethanol to enhance packing. This cycle is repeated numerous times to allow for a tightly packed channel of microbeads. Typical microbead packing occurs in the macroscale into tubes or channels by using highly pressurized systems. Moreover, these channels are typically long and straight without any turns or curves. On the other hand, this method of microbead packing is completed within a microchannel 75 micrometers in diameter. Moreover, the microbead packing is completed into a serpentine type microchannel, such that it maximizes microchannel length within a microchip. Doing so enhances the interactions of the analytes with the microbeads to separate efficiently amino acids and amino acid enantiomers.

Balvin, Manuel; Zheng, Yun

2013-01-01

199

Enabling Microliquid Chromatography by Microbead Packing of Microchannels  

NASA Technical Reports Server (NTRS)

The microbead packing is the critical element required in the success of on-chip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and low-power element to separate amino acids and their chiral partners efficiently to understand better the origin of life. In order to densely pack microbeads into the microchannels, a liquid slurry of microbeads was created. Microbeads were extracted from a commercially available high-performance liquid chromatography column. The silica beads extracted were 5 microns in diameter, and had surface coating of phenyl-hexyl. These microbeads were mixed with a 200- proof ethanol solution to create a microbead slurry with the right viscosity for packing. A microfilter is placed at the outlet via of the microchannel and the slurry is injected, then withdrawn across a filter using modified syringes. After each injection, the channel is flushed with ethanol to enhance packing. This cycle is repeated numerous times to allow for a tightly packed channel of microbeads. Typical microbead packing occurs in the macroscale into tubes or channels by using highly pressurized systems. Moreover, these channels are typically long and straight without any turns or curves. On the other hand, this method of microbead packing is completed within a microchannel 75 micrometers in diameter. Moreover, the microbead packing is completed into a serpentine type microchannel, such that it maximizes microchannel length within a microchip. Doing so enhances the interactions of the analytes with the microbeads to separate efficiently amino acids and amino acid enantiomers.

Balvin, Manuel; Zheng, Yun

2014-01-01

200

Downhole hydraulic seismic generator  

DOEpatents

A downhole hydraulic seismic generator system for transmitting energy wave vibrations into earth strata surrounding a borehole. The system contains an elongated, unitary housing operably connected to a well head aboveground by support and electrical cabling, and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a hydraulic oscillator containing a double-actuating piston whose movement is controlled by an electro-servovalve regulating a high pressure hydraulic fluid flow into and out of upper and lower chambers surrounding the piston. The spent hydraulic fluid from the hydraulic oscillator is stored and pumped back into the system to provide high pressure fluid for conducting another run at the same, or a different location within the borehole.

Gregory, Danny L. (Corrales, NM); Hardee, Harry C. (Albuquerque, NM); Smallwood, David O. (Albuquerque, NM)

1992-01-01

201

Downhole hydraulic seismic generator  

SciTech Connect

A downhole hydraulic seismic generator system for transmitting energy wave vibrations into earth strata surrounding a borehole. The system contains an elongated, unitary housing operably connected to a well head aboveground by support and electrical cabling, and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a hydraulic oscillator containing a double-actuating piston whose movement is controlled by an electro-servovalve regulating a high pressure hydraulic fluid flow into and out of upper and lower chambers surrounding the piston. The spent hydraulic fluid from the hydraulic oscillator is stored and pumped back into the system to provide high pressure fluid for conducting another run at the same, or a different location within the borehole. 4 figs.

Gregory, D.L.; Hardee, H.C.; Smallwood, D.O.

1990-12-31

202

Downhole hydraulic seismic generator  

SciTech Connect

A downhole hydraulic seismic generator system for transmitting energy wave vibrations into earth strata surrounding a borehole. The system contains an elongated, unitary housing operably connected to a well head aboveground by support and electrical cabling, and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a hydraulic oscillator containing a double-actuating piston whose movement is controlled by an electro-servovalve regulating a high pressure hydraulic fluid flow into and out of upper and lower chambers surrounding the piston. The spent hydraulic fluid from the hydraulic oscillator is stored and pumped back into the system to provide high pressure fluid for conducting another run at the same, or a different location within the borehole. 4 figs.

Gregory, D.L.; Hardee, H.C.; Smallwood, D.O.

1990-01-01

203

Method for packing chromatographic beds  

DOEpatents

Column chromatography beds are packed through the application of static force. A slurry of the chromatography bed material and a non-viscous liquid is filled into the column plugged at one end, and allowed to settle. The column is transferred to a centrifuge, and centrifuged for a brief period of time to achieve a predetermined packing level, at a range generally of 100-5,000 gravities. Thereafter, the plug is removed, other fixtures may be secured, and the liquid is allowed to flow out through the bed. This results in an evenly packed bed, with no channeling or preferential flow characteristics.

Freeman, David H. (Potomac, MD); Angeles, Rosalie M. (Germantown, MD); Keller, Suzanne (Rockville, MD)

1991-01-01

204

Packing grains by thermally cycling  

E-print Network

One of the oldest and most intriguing problems in the handling of materials is how a collection of solid grains packs together. While granular packing is normally determined by how grains are poured or shaken, we find that a systematic and controllable increase in packing is induced by simply raising and lowering the temperature, e.g., without the input of mechanical energy. The results demonstrate that thermal processing provides a largely unexplored mechanism of grain dynamics, as well as an important practical consideration in the handling and storage of granular materials.

K. Chen; J. Cole; C. Conger; J. Draskovic; M. Lohr; K. Klein; T. Scheidemantel; P. Schiffer

2006-08-04

205

Water vs. oil hydraulic actuation for a robot leg  

Microsoft Academic Search

The significant competitive advantage of hydraulics (high power density, large output force\\/torque and wide range of speeds) together with the properties of water (low compressibility, high thermal conductivity, low solubility of air, non-flammability and no environmental hazard) make water hydraulic actuation very suitable for systems such as legged robots. This paper addresses the comparison between a water and an oil

Yousheng Yang; Claudio Semini; Emanuele Guglielmino; Nikos G. Tsagarakis; Darwin G. Caldwell

2009-01-01

206

Response of Jammed Ellipsoid Packings  

NASA Astrophysics Data System (ADS)

We investigate the nature of the jamming transition for packings of spheroids by examining the elastic moduli as a function of the aspect ratio of the particles ? and the compression. Irrespective of the particle aspect ratio, both shear modulus G and bulk modulus B show the same scaling as a function of compression as is found for packings of spheres. Moreover, for any value of ?, G is proportional to the excess of the coordination number above that found at the jamming threshold; this recovers the result for frictionless spheres at ?=1. Our results imply a new diverging length scale associated with the loss of rigidity of these spheroid packings. The critical behavior of ellipsoid packings is an extension of that found for spheres.

Zeravcic, Zorana; Liu, Andrea; Nagel, Sidney

2011-03-01

207

Are proteins well-packed?  

PubMed Central

The average packing density inside proteins is as high as in crystalline solids. Does this mean proteins are well-packed? We go beyond average densities, and look at the full distribution functions of free volumes inside proteins. Using a new and rigorous Delaunay triangulation method for parsing space into empty and filled regions, we introduce formal definitions of interior and surface packing densities. Although proteins look like organic crystals by the criterion of average density, they look more like liquids and glasses by the criterion of their free volume distributions. The distributions are broad, and the scalings of volume-to-surface, volume-to-cluster-radius, and numbers of void versus volume show that the interiors of proteins are more like randomly packed spheres near their percolation threshold than like jigsaw puzzles. We find that larger proteins are packed more loosely than smaller proteins. And we find that the enthalpies of folding (per amino acid) are independent of the packing density of a protein, indicating that van der Waals interactions are not a dominant component of the folding forces. PMID:11463623

Liang, J; Dill, K A

2001-01-01

208

7 CFR 51.1270 - Packing.  

Code of Federal Regulations, 2011 CFR

...United States Standards for Summer and Fall Pears 1 Standard Pack § 51.1270 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2011-01-01

209

7 CFR 51.1311 - Packing.  

Code of Federal Regulations, 2013 CFR

... United States Standards for Winter Pears 1 Standard Pack § 51.1311 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2013-01-01

210

7 CFR 51.1311 - Packing.  

Code of Federal Regulations, 2012 CFR

... United States Standards for Winter Pears 1 Standard Pack § 51.1311 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2012-01-01

211

7 CFR 51.1270 - Packing.  

Code of Federal Regulations, 2010 CFR

...United States Standards for Summer and Fall Pears 1 Standard Pack § 51.1270 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2010-01-01

212

7 CFR 51.1311 - Packing.  

Code of Federal Regulations, 2014 CFR

... United States Standards for Winter Pears 1 Standard Pack § 51.1311 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2014-01-01

213

7 CFR 51.1270 - Packing.  

Code of Federal Regulations, 2013 CFR

...United States Standards for Summer and Fall Pears 1 Standard Pack § 51.1270 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2013-01-01

214

7 CFR 51.1311 - Packing.  

Code of Federal Regulations, 2011 CFR

... United States Standards for Winter Pears 1 Standard Pack § 51.1311 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2011-01-01

215

7 CFR 51.1270 - Packing.  

Code of Federal Regulations, 2014 CFR

...United States Standards for Summer and Fall Pears 1 Standard Pack § 51.1270 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2014-01-01

216

7 CFR 51.1311 - Packing.  

Code of Federal Regulations, 2010 CFR

... United States Standards for Winter Pears 1 Standard Pack § 51.1311 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2010-01-01

217

7 CFR 51.1270 - Packing.  

Code of Federal Regulations, 2012 CFR

...United States Standards for Summer and Fall Pears 1 Standard Pack § 51.1270 Packing...Each package shall be packed so that the pears in the shown face shall be reasonably...of the contents of the package. (b) Pears packed in any container shall be...

2012-01-01

218

THE SYMMETRY OF OPTIMALLY DENSE PACKINGS  

E-print Network

with packings of regular pentagons in the Euclidean plane, E 2 . First we recall that by a ``packing'' pTHE SYMMETRY OF OPTIMALLY DENSE PACKINGS by Charles Radin * Mathematics Department, University was the densest packings of simple bodies, for instance spheres or polyhedra, in Euclidean or hyperbolic spaces

219

Empirical equations for some soil hydraulic properties  

Microsoft Academic Search

with a power function relating soil moisture and hydraulic conductivitymis used to derive a formula for the wetting front suction required by the Green-Ampt equation. Representative parameters for the moisture charac- teristic, the wetting front suction, and the sorptivity, a parameter in the infiltration equation derived by Philip (1957), are computed by using the desorption data of Holtan et al.

Roger B. Clapp; George M. Hornberger

1978-01-01

220

Seawater hydraulic actuator system for underwater manipulator  

Microsoft Academic Search

A seawater hydraulic actuator system for a subsea robot has been developed. The system consists of a high pressure axial piston pump, flow control servovalves and actuators which transform controlled flow into motion, and it is very effective in miniaturizing a subsea robot. In order to confirm overall characteristic of this power systems, a prototype telemanipulator for underwater work has

Hiroshi YOSHINADA; Taku YAMAZAKI; Tatsunori SUWA; Toshihisa NARUSE; Hideo UEDA

1991-01-01

221

The crack tip region in hydraulic fracturing  

Microsoft Academic Search

We present analytical tip region solutions for fracture width and pressure when a power law fluid drives a plane strain fracture in an impermeable linear elastic solid. Our main result is an intermediate asymptotic solution in which the tip region stress is dominated by a singularity which is particular to the hydraulic fracturing problem. Moreover this singularity is weaker than

J. Desroches; E. Detournay; B. Lenoach; P. Papanastasiou; J. R. A. Pearson; M. Thiercelin; A. Cheng

1994-01-01

222

Using accumulators to solve hydraulic circuit problems  

Microsoft Academic Search

Accumulators can be useful to the plant engineer. Hydropneumatic or gas-charged version are used effectively in hydraulic circuits for auxiliary power, energy storage, emergency operation, leakage compensation or makeup fluid, and motor soft starts. Accumulators are also applied for shock absorption in pressure and tank lines, pulsation dampening, elimination of pump cavitation, and noise attenuation. The first reaction to a

Mordas

1994-01-01

223

Downstream hydraulic geometry relations: 1. Theoretical development  

E-print Network

In this study, it is hypothesized that (1) the spatial variation of the stream power of a channel for a given discharge is accomplished by the spatial variation in channel form (flow depth and channel width) and hydraulic variables, including energy...

Singh, Vijay P.; Yang, Chih Ted; Deng, Z. Q.

2003-12-04

224

AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT IX, AUTOMATIC TRANSMISSIONS--HYDRAULIC SYSTEM (PART I).  

ERIC Educational Resources Information Center

THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OIL FLOW WITHIN HYDRAULIC TRANSMISSIONS USED ON DIESEL POWERED VEHICLES. TOPICS ARE GENERAL DESCRIPTION, HYDRAULIC CIRCUITS, AND BRAKE HYDRAULIC CIRCUIT AND OPERATION. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL PROGRAMED TRAINING FILM "LEARNING ABOUT THE ALLISON…

Human Engineering Inst., Cleveland, OH.

225

POSITION TRACKING CONTROL OF MINIATURE LOW PRESSURE WATER HYDRAULIC CYLINDERS Russell Sindrey and Gary M. Bone  

E-print Network

POSITION TRACKING CONTROL OF MINIATURE LOW PRESSURE WATER HYDRAULIC CYLINDERS Russell Sindrey capability. Hydraulic cylinders offer many potential benefits as miniature actuators including: high power their benefits the control of hydraulic cylinders with bore diameters under 10 mm has not been previously studied

Bone, Gary

226

Hydraulic Fracturing Sand  

USGS Multimedia Gallery

Fine-grained silica sand is mixed with chemicals and water before being pumped into rock formations to prevent the newly created artificial fractures from closing after hydraulic fracturing is completed....

227

Automatic emergency hydraulic switch  

Microsoft Academic Search

tem automatically when large leaks appear in the system, or when the process piping ruptures suddenly, has been developed and tested at Penza Polytechnic Institute. This emergency hydraulic switch can be employed in various hydraulic systems serviug process machinery and equipment. It is designed to handle maximum flowrates at i00 liters\\/min, and to take pressures up to 200 kgf\\/cm 2.

B. T. Sitnikov; I. B. Matveev; V. N. Denisov

1972-01-01

228

Free-piston regenerative hot gas hydraulic engine  

NASA Technical Reports Server (NTRS)

A displacer piston which is driven pneumatically by a high-pressure or low-pressure gas is included in a free-piston regenerative hydraulic engine. Actuation of the displacer piston circulates the working fluid through a heater, a regenerator and a cooler. The present invention includes an inertial mass such as a piston or a hydraulic fluid column to effectively store and supply energy during portions of the cycle. Power is transmitted from the working fluid to a hydraulic fluid across a diaphragm or lightweight piston to achieve a hydraulic power out-put. The displacer piston of the present invention may be driven pneumatically, hydraulically or electromagnetically. In addition, the displacer piston and the inertial mass of the present invention may be positioned on the same side of the diaphragm member or may be separated by the diaphragm member.

Beremand, D. G. (inventor)

1980-01-01

229

Fluid flow through packings of rotating obstacles  

NASA Astrophysics Data System (ADS)

We investigate through numerical simulation the nonstationary flow of a Newtonian fluid through a two-dimensional channel filled with an array of circular obstacles of distinct sizes. The disks may rotate around their respective centers, modeling a nonstationary, inhomogeneous porous medium. Obstacle sizes and positions are defined by the geometry of an Apollonian packing (AP). To allow for fluid flow, the radii of the disks are uniformly reduced by a factor 0.6 ?s ?0.8 for assemblies corresponding to the four first AP generations. The investigation is targeted to elucidate the main features of the rotating regime as compared to the fixed disk condition. It comprises the evaluation of the region of validity of Darcy's law as well as the study of the nonlinear hydraulic resistance as a function of the channel Reynolds number, the reduction factor s , and the AP generation. Depending on a combination of these factors, the resistance of rotating disks may be larger or smaller than that of the corresponding static case. We also analyze the flow redistribution in the interdisk channels as a result of the rotation pattern and characterize the angular velocity of the disks. Here, the striking feature is the emergence of a stable oscillatory behavior of the angular velocity for almost all disks that are inserted into the assemblies after the second generation.

Oliveira, Rafael S.; Andrade, José S.; Andrade, Roberto F. S.

2015-03-01

230

Sleeping distance in wild wolf packs  

USGS Publications Warehouse

Sleeping distances were observed among members of 13 wild wolf (Canis lupus) packs and 11 pairs in northeastern Minnesota to determine if the distances correlated with pack size and composition. The study utilized aerial radio-tracking and observation during winter. Pack size and number of adults per pack were inversely related to pack average sleeping distance and variability. No correlation between sleeping distance and microclimate was observed. Possible relationships between social bonding and our results are discussed.

Knick, S.T.; Mech, L.D.

1980-01-01

231

Steady state thermal hydraulic analysis of hydride fueled BWRs  

E-print Network

(cont.) Since the results obtained in the main body of the analysis account only for thermal-hydraulic constraints, an estimate of the power reduction due to the application of neutronic constraints is also performed. This ...

Ferroni, Paolo, Ph. D. Massachusetts Institute of Technology

2006-01-01

232

IOWA INSTITUTE OF HYDRAULIC RESEARCH THE UNIVERSITY OF IOWA  

E-print Network

at Power Plants EPRIa Odgaard, Nakato Icing-Induced Vibration of Cables EPRIa Ettema, Nixon ** Hydraulic ** Test Erodibility of Rock From Mississippi River, U.S. 34 Bridge at Burlington, IA IDOT Nakato

Stanier, Charlie

233

Laboratory sandbox validation of transient hydraulic tomography  

Microsoft Academic Search

(1) Hydraulic tomography is a method that images the hydraulic heterogeneity of the subsurface through the inversion of multiple pumping or cross-hole hydraulic test data. Transient hydraulic tomography is different from steady state hydraulic tomography in that it utilizes transient hydraulic head records to yield the distribution of hydraulic conductivity (K) as well as specific storage (Ss) of an aquifer.

X. Liu; W. A. Illman; A. J. Craig; J. Zhu; T.-C. J. Yeh

2007-01-01

234

Hydraulic generator with free-piston engine  

SciTech Connect

A hydraulic generator is disclosed with a free-piston engine and hydropneumatic return cushion and with an associated hydraulic-fluid pumping piston feeding a hydraulic accumulator intended to be charged between two detected levels of pressure. The generator includes a lock device for the free piston at the power-stroke dead center with voluntary control, and servo-control means for this lock device with means for detection of the aforementioned two pressure levels, to assure locking the piston in response to detection of the aforementioned highest pressure level and to assure its unlocking in response to detection of the aforementioned lowest pressure level, and thus an automatic intermittent running of said engine.

Bouthers, P.; Breting, O.

1983-11-15

235

Cylinder valve packing nut studies  

SciTech Connect

The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

1991-12-31

236

Effect of exchangeable Mg on saturated hydraulic conductivity, disaggregation and clay dispersion of disturbed soils  

Microsoft Academic Search

Different opinions exist regarding the specific effect of Mg on soil physical and chemical properties. We hypothesized that Mg2+, compared with Ca2+, reduces saturated hydraulic conductivity (Ks) via promoting clay swelling, disaggregation, and clay dispersion. Two soils (mixed, mesic Typic Hapludalfs) in packed soil columns were leached with either Ca- or Mg-containing solutions at the successive concentrations of 250, 10,

X. C Zhang; L. D Norton

2002-01-01

237

Dense crystalline dimer packings of regular tetrahedra  

E-print Network

We present the densest known packing of regular tetrahedra with density phi = 4000/4671 = 0.856347... Like the recently discovered packings of Kallus et al. [arXiv:0910.5226] and Torquato-Jiao [arXiv:0912.4210], our packing is crystalline with a unit cell of four tetrahedra forming two triangular dipyramids (dimer clusters). We show that our packing has maximal density within a three-parameter family of dimer packings. Numerical compressions starting from random configurations suggest that the packing may be optimal at least for small cells with up to 16 tetrahedra and periodic boundaries.

Elizabeth R. Chen; Michael Engel; Sharon C. Glotzer

2010-07-25

238

Generation of Random Particle Packings for Discrete Element Models  

NASA Astrophysics Data System (ADS)

An important step in the setup process of Discrete Element Model (DEM) simulations is the generation of a suitable particle packing. There are quite a number of properties such a granular material specimen should ideally have, such as high coordination number, isotropy, the ability to fill arbitrary bounding volumes and the absence of locked-in stresses. An algorithm which is able to produce specimens fulfilling these requirements is the insertion based sphere packing algorithm originally proposed by Place and Mora, 2001 [2] and extended in this work. The algorithm works in two stages. First a number of "seed" spheres are inserted into the bounding volume. In the second stage the gaps between the "seed" spheres are filled by inserting new spheres in a way so they have D+1 (i.e. 3 in 2D, 4 in 3D) touching contacts with either other spheres or the boundaries of the enclosing volume. Here we present an implementation of the algorithm and a systematic statistical analysis of the generated sphere packings. The analysis of the particle radius distribution shows that they follow a power-law with an exponent ? D (i.e. ?3 for a 3D packing and ?2 for 2D). Although the algorithm intrinsically guarantees coordination numbers of at least 4 in 3D and 3 in 2D, the coordination numbers realized in the generated packings can be significantly higher, reaching beyond 50 if the range of particle radii is sufficiently large. Even for relatively small ranges of particle sizes (e.g. Rmin = 0.5Rmax) the maximum coordination number may exceed 10. The degree of isotropy of the generated sphere packing is also analysed in both 2D and 3D, by measuring the distribution of orientations of vectors joining the centres of adjacent particles. If the range of particle sizes is small, the packing algorithm yields moderate anisotropy approaching that expected for a face-centred cubic packing of equal-sized particles. However, once Rmin < 0.3Rmax a very high degree of isotropy is demonstrated in both 2D and 3D. The analysis demonstrates that this space-filling packing algorithm fulfills many of the requirements required to produce granular material specimens for DEM simulations. These include a high coordination number, isotropy and the absence of lock-in stresses. The algorithm has been implemented as a module (called gengeo[1]) for the Python[3] scripting language and provides the capacity to fill arbitrary bounding volumes or combinations of bounding volumes. The main disadvantage of this space-filling packing approach is the inability to specify a priori the particle size distribution of the final specimen.

Abe, S.; Weatherley, D.; Ayton, T.

2012-04-01

239

Microfabricated packed gas chromatographic column  

DOEpatents

A new class of miniaturized gas chromatographic columns has been invented. These chromatographic columns are formed using conventional micromachining techniques, and allow packed columns having lengths on the order of a meter to be fabricated with a footprint on the order of a square centimeter.

Kottenstette, Richard; Matzke, Carolyn M.; Frye-Mason, Gregory C.

2003-12-16

240

Packing Schemes for Gang Scheduling  

Microsoft Academic Search

. Jobs that do not require all processors in the system can bepacked together for gang scheduling. We examine accounting traces fromseveral parallel computers to show that indeed many jobs have small sizesand can be packed together. We then formulate a number of such packingalgorithms, and evaluate their effectiveness using simulations based onour workload study. The results are that two

Dror G. Feitelson

1996-01-01

241

Mirror, Mirror ClassPack  

NSDL National Science Digital Library

Using More Picture-Perfect Science Lessons: Using Children's Books to Guide Inquiry, K-4 in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatche

2010-04-25

242

Loco Beans ClassPack  

NSDL National Science Digital Library

Using More Picture-Perfect Science Lessons: Using Children's Books to Guide Inquiry, K-4 in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatche

2010-04-22

243

Roller Coasters ClassPack  

NSDL National Science Digital Library

Using More Picture-Perfect Science Lessons: Using Children's Books to Guide Inquiry, K-4 in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatche

2010-04-25

244

Wiggling Worms ClassPack  

NSDL National Science Digital Library

Using More Picture-Perfect Science Lessons: Using Children's Books to Guide Inquiry, K-4 in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatche

2010-04-23

245

Electromechanics of packed granular beds  

Microsoft Academic Search

Strong, electrical, interparticle forces are induced by applied electric fields within packed beds of dielectric particles. Proposed applications utilizing electropacked beds (EPBs) or electrofluidized beds (EFBs) include air filtration and gas clean-up, fine particle separation, commercial drying and coating processes, heat and mass transfer, and bulk bed control. A new distributed circuit model of the electrical interparticle force is presented

1982-01-01

246

Oil Spill! ClassPack  

NSDL National Science Digital Library

Using Picture-Perfect Science Lessons in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatched time-saver and a great deal. This Cla

2010-04-21

247

Grand Canyon ClassPack  

NSDL National Science Digital Library

Using Picture-Perfect Science Lessons in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatched time-saver and a great deal. This Cla

2010-04-22

248

Method of gravel packing wells  

Microsoft Academic Search

A method of gravel packing a well in an overpressured formation is described in which a gravel-carrying liquid is formed by mixing finely divided solid particles of a weighting agent with the liquid. The weighting agent is either soluble in, or can be made soluble by, a liquid that has no appreciable effect on the gravel. Gravel is suspended in

W. C. Jr. Goins; B. B. McGlothlin

1972-01-01

249

TU Delft: Hydraulic Engineering  

NSDL National Science Digital Library

Given the Dutch reputation for water management, it's no surprise that one of their leading technical institutes, The Technische Universiteit Delft, offers a program in Hydraulic Engineering. The website, in both Dutch and English, describes their program as an attempt "to bridge the gap between basic sciences (fluid mechanics and soil mechanics in particular) and practical engineering applications in the design, construction, maintenance, management and eventually the demolition of hydraulic structures." The Education section of the website posts MSc theses completed by their students. The research section describes current and recently completed research projects and includes a listing of publications, some of which are available to download. The website also has a link to a Hydraulic Engineering portal, which offers various publication databases (some in Dutch only), and the Civil Engineering Knowledge Centre, which provides library access and discussion forums for students and staff of Civil Engineering.

250

Hydrogen storage for fuel cell systems with stationary applications— I. Transient measurement technique for packed bed evaluation  

Microsoft Academic Search

Data are presented on a metal hydride storage unit used as a hydrogen source for a 500 W fuel cell power supply system powering the electrical components of a gas furnace. The investigated packed bed had special design features for the internal heat transfer optimization: the hydride material was packed into Al foam, and an inner coaxial U-shaped tube enabled

S Lévesque; M Ciureanu; R Roberge; Theodore Motyka

2000-01-01

251

Mechanical behavior and design database of packed beds for blanket designs  

Microsoft Academic Search

The mechanical behavior and properties of particle beds relevant to fusion ceramic breeder blanket designs are addressed through a combination of experimental and analytical studies. A series of uniaxial compression tests are performed in a INSTRON hydraulic-press test facility in which compressive loads are applied to Li2ZrO3 and aluminum packed beds. The experimental data shows that the mechanical properties such

Alice Y. Ying; Zi Lu; Mohamed A. Abdou

1998-01-01

252

Hydraulics of wells  

USGS Publications Warehouse

Although the subject of this lecture is supposed to be concerned primarily with the hydraulics of wells, Professor Weers has asked that I also discuss the effects tat geological formations have on the quantity and quality of water available to wells. I will discuss the geology of Colorado in relation to the availability and quality of water with particular reference to the most productive aquifers or water-bearing formations in the State. I will then discuss the hydraulics of wells with the aim of emphasizing the differences between water-table and artesian conditions.

McLaughlin, Thad G.

1955-01-01

253

What Is Hydraulic Fracturing?  

NSDL National Science Digital Library

Hydraulic fracturing is a process used in nine out of 10 natural gas wells in the United States, where millions of gallons of water, sand and chemicals are pumped underground to break apart the rock and release the gas. Scientists are worried that the chemicals used in fracturing may pose a threat either underground or when waste fluids are handled and sometimes spilled on the surface. This poster presentation illustrates the under surface process of hydraulic fracking and the distribution flow to the market.

2012-01-01

254

Geostatistical inference of hydraulic conductivity and dispersivities from hydraulic heads and tracer data  

E-print Network

Geostatistical inference of hydraulic conductivity and dispersivities from hydraulic heads; accepted 25 April 2006; published 10 August 2006. [1] In groundwater, hydraulic heads and solute arrival times depend primarily on the hydraulic conductivity field and hydraulic boundary conditions. The spread

Cirpka, Olaf Arie

255

Efficient hydraulic properties of root systems  

NASA Astrophysics Data System (ADS)

Understanding the mechanisms of ecosystem root water uptake (RWU) is paramount for parameterizing hydrological models. With the increase in computational power it is possible to calculate RWU explicitly up to the single plant scale using physical models. However, application of these models for increasing our understanding of ecosystem root water uptake is hindered by the deficit in knowledge about the detailed hydraulic parameter distribution within root systems. However, those physical models may help us to identify efficient parameterizations and to describe the influence of these hydraulic parameters on RWU profiles. In this research, we investigated the combined influence of root hydraulic parameters and different root topologies on shaping efficient root water uptake. First, we use a conceptual model of simple branching structures to understand the influence of branching location and transitions in root hydraulic properties on the RWU patterns in typical sub root structures. Second, we apply a physical model called "aRoot" to test our conclusions on complex root system architectures of single plants. aRoot calculates the distribution of xylem potential within arbitrary root geometries to satisfy a given water demand depending on the available water in the soil. Redistribution of water within the bulk soil is calculated using the Richards equation. We analyzed results using a measure of uptake efficiency, which describes the effort necessary for transpiration. Simulations with the conceptual model showed that total transpiration in sub root structures is independent of root hydraulic properties over a wide range of hydraulic parameters. On the other hand efficiency of root water uptake depends crucially on distribution hydraulic parameters in line with root topology. At the same time, these parameters shape strongly the distribution of RWU along the roots, and its evolution in time, thus leading to variable individual root water uptake profiles. Calculating RWU of three dimensional root architectures unveiled that the same effects can be observed at the single plant scale. Total transpiration is almost independent of root hydraulic properties. On the other hand, the arrangement of hydraulic properties significantly influences RWU efficiency. Furthermore the vertical root water uptake profiles are governed by the different root properties. They result from two combined re-distribution patterns over time: One within a rooting branch similar to the results mentioned above, and a second one between the different rooting branches within the root system. This leads to complex vertical uptake profiles, which cannot be predicted from a combination of root abundance and soil moisture, and depend strongly on the individual morphology.

Bechmann, Marcel; Schneider, Christoph; Carminati, Andrea; Hildebrandt, Anke

2013-04-01

256

Determining the Porosity and Saturated Hydraulic Conductivity of Binary Mixtures  

SciTech Connect

Gravels and coarse sands make up significant portions of some environmentally important sediments, while the hydraulic properties of the sediments are typically obtained in the laboratory using only the fine fraction (e.g., <2 mm or 4.75 mm). Researchers have found that the content of gravel has significant impacts on the hydraulic properties of the bulk soils. Laboratory experiments were conducted to measure the porosity and the saturated hydraulic conductivity of binary mixtures with different fractions of coarse and fine components. We proposed a mixing-coefficient model to estimate the porosity and a power-averaging method to determine the effective particle diameter and further to predict the saturated hydraulic conductivity of binary mixtures. The proposed methods could well estimate the porosity and saturated hydraulic conductivity of the binary mixtures for the full range of gravel contents and was successfully applied to two data sets in the literature.

Zhang, Z. F.; Ward, Anderson L.; Keller, Jason M.

2009-09-27

257

Contact forces in a granular packing.  

PubMed

We present the results of a systematic numerical investigation of force distributions in granular packings. We find that all the main features of force transmission previously established for two-dimensional systems of hard particles hold in three-dimensional systems and for soft particles, too. In particular, the probability distribution of normal forces falls off exponentially for forces above the mean force. For forces below the mean, this distribution is either a decreasing power law when the system is far from static equilibrium, or nearly uniform at static equilibrium, in agreement with recent experiments. Moreover, we show that the forces below the mean do not contribute to the shear stress. The subnetwork of the contacts carrying a force below the mean thus plays a role similar to a fluid surrounding the solid backbone composed of the contacts carrying a force above the mean. We address the issue of the computation of contact forces in a packing at static equilibrium. We introduce a model with no local simplifying force rules, that allows for an exact computation of contact forces for given granular texture and boundary conditions. (c) 1999 American Institute of Physics. PMID:12779850

Radjai, Farhang; Roux, Stephane; Moreau, Jean Jacques

1999-09-01

258

7 CFR 906.10 - Pack.  

Code of Federal Regulations, 2010 CFR

...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ORANGES AND GRAPEFRUIT GROWN IN LOWER RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Definitions § 906.10 Pack. Pack...

2010-01-01

259

7 CFR 958.16 - Pack.  

Code of Federal Regulations, 2012 CFR

...Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ONIONS GROWN IN CERTAIN DESIGNATED COUNTIES IN IDAHO, AND MALHEUR COUNTY, OREGON Order Regulating Handling Definitions § 958.16 Pack. Pack means a quantity...

2012-01-01

260

7 CFR 945.15 - Pack.  

Code of Federal Regulations, 2010 CFR

...and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN CERTAIN DESIGNATED COUNTIES IN IDAHO, AND MALHEUR COUNTY, OREGON Order Regulating Handling Definitions § 945.15 Pack. Pack means a quantity...

2010-01-01

261

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2014 CFR

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification. A cold pack is a...

2014-04-01

262

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2012 CFR

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification. A cold pack is a...

2012-04-01

263

7 CFR 917.13 - Pack.  

Code of Federal Regulations, 2010 CFR

...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 917.13 Pack. Pack means the specific...

2010-01-01

264

Laboratory Determination of Hydraulic Conductivity  

NSDL National Science Digital Library

From D.B. McWhorterand D. K. Sunda's 1977 Ground-Water Hydrology and Hydraulics, this two page excerpt outlines and details Laboratory Determination of Hydraulic Conductivity. Here, visitors will find illustrations and formula to understand the concept.

265

46 CFR 28.880 - Hydraulic equipment.  

Code of Federal Regulations, 2014 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2014-10-01

266

46 CFR 28.405 - Hydraulic equipment.  

Code of Federal Regulations, 2012 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2012-10-01

267

46 CFR 28.405 - Hydraulic equipment.  

Code of Federal Regulations, 2011 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2011-10-01

268

46 CFR 28.405 - Hydraulic equipment.  

Code of Federal Regulations, 2013 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2013-10-01

269

46 CFR 28.405 - Hydraulic equipment.  

Code of Federal Regulations, 2014 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2014-10-01

270

46 CFR 28.405 - Hydraulic equipment.  

Code of Federal Regulations, 2010 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2010-10-01

271

46 CFR 28.880 - Hydraulic equipment.  

Code of Federal Regulations, 2013 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2013-10-01

272

46 CFR 28.880 - Hydraulic equipment.  

Code of Federal Regulations, 2011 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2011-10-01

273

46 CFR 28.880 - Hydraulic equipment.  

Code of Federal Regulations, 2012 CFR

...Hydraulic equipment. (a) Each hydraulic system must be so designed and installed...operating pressure. (c) Each hydraulic system must be equipped with at least... (d) All material in a hydraulic system must be suitable for use...

2012-10-01

274

Random Close Packings of Regular Polygons  

NASA Astrophysics Data System (ADS)

We study by numerical simulation the progressive densification of assemblies of equal regular polygons (pentagons and heptagons). We follow the evolution of the packing fraction, of the coordination numbers and of the void space structure during the densification. At high packing fraction (Csim 0.83), ordered zones appear. This can be compared with what occurs in equal disc assemblies in which a Random Close Packing limit exists for a packing fraction Csim 0.83 above which some local order is present.

Limon Duparcmeur, Y.; Troadec, J. P.; Gervois, A.

1997-10-01

275

Integration in Hydraulics.  

ERIC Educational Resources Information Center

This paper presents an application of integration to the field of hydraulics. An integral relation for the time required to drop the fluid contained in a cylindrical tank from one level to another using a hole in the tank wall is derived. Procedures for constructing the experimental equipment and procedures for determining the coefficient of…

Sworder, Steven C.

276

Water Treatment Technology - Hydraulics.  

ERIC Educational Resources Information Center

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…

Ross-Harrington, Melinda; Kincaid, G. David

277

Hydraulic Shutdown Monitor  

NASA Technical Reports Server (NTRS)

Adding switch allows inappropriate control actions to be overridden. Four-pole, double-throw switch added to front panel of controller to disable tracking-error and endpoint-error circuitry yet still retain overload-detection capability. Previously, it was necessary to use adjustable-voltage-level detection equipment connected with cables to hydraulic "dump" or shutdown circuitry in controller.

Fleming, S. T.; Harrington, D. B.

1986-01-01

278

Modular hydraulic control system  

Microsoft Academic Search

A system of modular electrohydraulic servovalves is centrally controlled and may be used to control the operation of critical hydraulic actuators. A programmable controller operates a group of modular servovalves which each deliver a portion of the total actuator fluid requirements. The flow rate, valve position, and valve pressure of each servovalve is monitored by the controller and compared to

David C. Winyard; Waldemar C. Lindstrom

1994-01-01

279

Characteristics of hydrostatic bearing\\/seal parts for water hydraulic pumps and motors. Part 2: On eccentric loading and power losses  

Microsoft Academic Search

In this paper, the load-carrying capacity, power losses and stiffness of disk-type hydrostatic thrust bearings including the case of eccentric loading are discussed theoretically. The numerical analysis method is established based on a two-dimensional elastohydrostatic problem with an elastic deformation model, which is extended to adapt it for a non-axisymmetric load acting on the thrust bearing. The bearing is made

X. Wang; A. Yamaguchi

2002-01-01

280

Characteristics of fluidized-packed beds  

NASA Technical Reports Server (NTRS)

Study of fluidized-packed bed includes investigation of heat transfer, solids-gas mixing, and elutriation characteristics. A fluidized-packed bed is a system involving the fluidization of small particles in the voids of a packed bed of larger nonfluidized particles.

Gabor, J. D.; Mecham, W. J.

1968-01-01

281

Gas flow distribution in packed columns  

Microsoft Academic Search

The distribution of gas flow over the cross section of packed columns depends on the manner of gas flow feeding, on packing type, packing arrangement, and internal devices in the apparatus body. Various types of gas inlet devices are studied in order to estimate their ability for creation of uniform velocity profiles. The gas flow uniformity is characterized by the

Rumen Darakchiev; Chavdar Dodev

2002-01-01

282

7 CFR 51.1217 - Standard pack.  

Code of Federal Regulations, 2010 CFR

... United States Standards for Grades of Peaches Standard Pack § 51.1217 Standard...Each package shall be packed so that the peaches in the shown face shall be reasonably...the contents of the package. (b) Peaches packed in U.S. Standard bushel...

2010-01-01

283

Investigation of reliability of hydraulic-robots for hazardous environments using analytic redundancy  

Microsoft Academic Search

The Rosie mobile worksystem is a robot that is on the cutting edge of hazardous environment robotics. It is a heavy-duty hydraulic robot designed for nuclear reactor decontamination and dismantlement. The robot consists of a wheeled platform containing a central hydraulic power supply powered by an electric tether, four independently steerable wheels, and a heavy-duty crane\\/manipulator. The hydraulic wheel actuator

Martin L. Leuschen; Ian D. Walker; Joseph R. Cavallaro

1999-01-01

284

ccsd00000707 GALACTIC HYDRAULIC DROP?  

E-print Network

). #12; Figure 1: The circular hydraulic jump, as observed in any kitchen sink. The water chooses oneccsd­00000707 (version 1) : 10 Oct 2003 GALACTIC HYDRAULIC DROP? STEEN H. HANSEN University a break at some characteristic radius, providing us with a galactic hydraulic drop. In the #12;eld

285

Viscous Hydraulic Jumps Submitted by  

E-print Network

Viscous Hydraulic Jumps Submitted by Jeffrey M. Aristoff, Jeffrey D. Leblanc, Annette E. Hosoi, and John W. M. Bush, Massachusetts Institute of Technology We examine the form of the viscous hydraulic of height 2­10 mm. Elegaard et al.1 first demonstrated that the axial symme- try of the viscous hydraulic

Bush, John W.M.

286

Computer simulation of hydraulic fractures  

Microsoft Academic Search

We provide a brief historical background of the development of hydraulic fracturing models for use in the petroleum and other industries. We discuss scaling laws and the propagation regimes that control the growth of hydraulic fractures from the laboratory to the field scale. We introduce the mathematical equations and boundary conditions that govern the hydraulic fracturing process, and discuss numerical

J. Adachi; E. Siebrits; A. Peirce; J. Desroches

2007-01-01

287

Frac and pack stimulation: Application and field experience from Hylia Gabon, West Africa  

SciTech Connect

This paper describes a two-step frac/gravel pack completion procedure conducted from a jack-up rig offshore Gabon in 1993 and 1994. After an in-depth, sand production study, seven wells were completed using hydraulic fracturing and cased-hole gravel packs. Because the Anguille formation spreads over a large gross interval, production screens of 50 to 100 m in length were used. Single-stage internal gravel packs (IGPs) on such large intervals were considered impossible to achieve with reasonable skin values. The frac-pack technique was an attractive way to achieve good proppant placement, considering that the formation being fractured would have a more homogeneous conductivity across the whole zone and a uniform proppant placement would be achieved in the perforations as well as in the annulus. High-efficiency frac gel using cross-linked HPG and a low damage one using HEC were compared to determine the best fluid to be used for these completions. Bottom hole pressures during treatment operations, as well as post-treatment pressure build-ups from each well, were analyzed in order to make general recommendations on this hydraulic fracture design.

Petit, G.; Leschi, P.; Dusterhoft, R.

1995-12-31

288

Local Anisotropy in Globally Isotropic Granular Packings  

NASA Astrophysics Data System (ADS)

We report on two-dimensional computer simulations of frictionless granular packings at various area fractions ? above the jamming point ?c. We measure the anisotropy in coarse-grained stress ?s and shear modulus ?m as functions of coarse-graining scale, R. ?s can be collapsed onto a master curve after rescaling R by a characteristic length scale ? and ?s by an anisotropy magnitude A. Both A and ? accelerate as ???c from above, consistent with a divergence at ?c. ?m shows no characteristic length scale and has a nontrivial power-law form, ?m˜R-0.62, over almost the entire range of R at all ?. These results suggest that the force chains present in the spatial structure of the quenched stress may be governed by different physics than the anomalous elastic response near jamming.

Karimi, K.; Maloney, C. E.

2011-12-01

289

Shearing of frictional sphere packings  

Microsoft Academic Search

We measure shear response in packings of glass beads by pulling a thin,\\u000arough, metal plate vertically through a bed of volume fraction phi, which is\\u000aset, before the plate is pulled, in the range 0.575 to 0.628. The yield stress\\u000ais velocity independent over 4 decades and increases exponentially with phi,\\u000awith a transition at phi approximately 0.595. An

Jean-François Métayer; Donald J. Suntrup III; Charles Radin; Harry L. Swinney; Matthias Schröter

2010-01-01

290

Using accumulators to solve hydraulic circuit problems  

SciTech Connect

Accumulators can be useful to the plant engineer. Hydropneumatic or gas-charged version are used effectively in hydraulic circuits for auxiliary power, energy storage, emergency operation, leakage compensation or makeup fluid, and motor soft starts. Accumulators are also applied for shock absorption in pressure and tank lines, pulsation dampening, elimination of pump cavitation, and noise attenuation. The first reaction to a malfunction in a hydraulic circuit is to check the pump and valves. Many times the problem may be flow related, either too much or too little. Jeffrey B. Mordas of Hydac Corp. explains how an accumulator resolves difficulties with fluid circuits and provides auxiliary power, energy storage, shock absorption, pulsation dampening, and noise attenuation.

Mordas, J.B. (Hydac Corp., Bethlehem, PA (United States))

1994-01-01

291

Apollonian circle packings: Number theory II. Spherical and hyperbolic packings  

Microsoft Academic Search

Apollonian circle packings arise by repeatedly filling the interstices between mutually tangent circles with further tangent\\u000a circles. In Euclidean space it is possible for every circle in such a packing to have integer radius of curvature, and we\\u000a call such a packing an integral Apollonian circle packing. There are infinitely many different integral packings; these were studied in Part I (J. Number

Nicholas Eriksson; Jeffrey C. Lagarias

2007-01-01

292

On the dynamics of hydraulic lines supplying servosystems  

NASA Astrophysics Data System (ADS)

Measures for achieving an almost quiescent state of hydraulic power supply pressure are outlined. Models for hydraulic pipelines supplying hydraulic control systems, which integrate dynamic behavior of the pipelines, the pressure control valve, or pressure controlled variable displacement pump, gas accumulators, and Helmholtz resonators are developed. Experiments show that pressure fluctuations due to pump flow pulsations are suppressed by a selective filter or by a small gas accumulator. Helmholtz resonator is most effective for eliminating one specific frequency of pump flow pulsation. A gas accumulator close to the pump suppresses pulsations in a wide frequency range. Pressure fluctuations due to the varying servomotor oil consumption are suppressed by an accumulator near the servovalve.

Ham, A. A.

1982-01-01

293

Developments in hydraulic engineering - Volume 4  

SciTech Connect

State-of-the-art reviews are presented on the following topics: (1) lake hydraulics; (2) tidal power generation; (3) multiphase flows in porous media; (4) groundwater flows and pollution in fractured rock aquifers; (5) groundwater models; and (6) groundwater utilization and protection. These reviews are more extensive than papers in technical or scientific journals, yet shorter than books or monographs. One article is processed separately for inclusion in the appropriate data bases.

Novak, P. (ed.)

1987-01-01

294

Synchronization control of hydraulic horizontal regulation system  

Microsoft Academic Search

This paper presents a control algorithm to address the leveling issue for lifting vehicle. The leveling system is achieved by electro-hydraulic system because of its advantages, such as small size-to-power ratios and so on. As four cylinders used to achieve synchronization, the issue of cylinder redundancy appears. In order to address this issue, the approach that two cylinders are only

Haibin Dou; Shaoping Wang

2011-01-01

295

Piezoelectric Hydraulic Pump System Dynamic Model  

Microsoft Academic Search

A system dynamic model was developed for use in the design of piezohydraulic pumps. The model was implemented in MATLAB to predict the electrical\\/mechanical\\/fluid coupled behavior of the piezoelectric pump system. Model results were used in a performance assessment of a pumping system that was comprised of a stack actuator driven pump, accumulator, power supply, four-way valve, and hydraulic actuator.

William S. Oates; Christopher S. Lynch

2001-01-01

296

Adhesive Loose Packings of Small Particles  

E-print Network

We explore adhesive loose packings of dry small spherical particles of micrometer size using 3D discrete-element simulations with adhesive contact mechanics. A dimensionless adhesion parameter ($Ad$) successfully combines the effects of particle velocities, sizes and the work of adhesion, identifying a universal regime of adhesive packings for $Ad>1$. The structural properties of the packings in this regime are well described by an ensemble approach based on a coarse-grained volume function that includes correlations between bulk and contact spheres. Our theoretical and numerical results predict: (i) An equation of state for adhesive loose packings that appears as a continuation from the frictionless random close packing (RCP) point in the jamming phase diagram; (ii) The existence of a maximal loose packing point at the coordination number $Z=2$ and packing fraction $\\phi=1/2^{3}$. Our results highlight that adhesion leads to a universal packing regime at packing fractions much smaller than the random loose packing, which can be described within a statistical mechanical framework. We present a general phase diagram of jammed matter comprising frictionless, frictional, adhesive as well as non-spherical particles, providing a classification of packings in terms of their continuation from the spherical frictionless RCP.

Wenwei Liu; Shuiqing Li; Adrian Baule; Hernán A. Makse

2014-10-08

297

Hydraulic manipulator research at ORNL  

SciTech Connect

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.

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)

1997-03-01

298

Kinetics of pack aluminization of nickel  

NASA Technical Reports Server (NTRS)

The kinetics of pack aluminization of unalloyed nickel in packs of varying aluminum activity with various halide activators were studied. Surface compositions of the coatings as functions of time, temperature, and pack composition were obtained in order to establish the boundary conditions for diffusion in the system. The structure of the packs was also examined in order to clarify the mechanism of aluminum transport. The results indicate that the kinetics of pack aluminization are controlled jointly by gas diffusion in the pack and solid diffusion in the coating. Levine and Caves' model for gas diffusion was combined with calculations of rates of diffusion in the solid to formulate a more complete theory for the kinetics of pack aluminization.

Seigle, L. L.; Gupta, B. K.; Shankar, R.; Sarkhel, A. K.

1978-01-01

299

Combustion waves in hydraulically resisted systems.  

PubMed

The effects of hydraulic resistance on the burning of confined/obstacle-laden gaseous and gas-permeable solid explosives are discussed on the basis of recent research. Hydraulic resistance is found to induce a new powerful mechanism for the reaction spread (diffusion of pressure) allowing for both fast subsonic as well as supersonic propagation. Hydraulic resistance appears to be of relevance also for the multiplicity of detonation regimes as well as for the transitions from slow conductive to fast convective, choked or detonative burning. A quasi-one-dimensional Fanno-type model for premixed gas combustion in an obstructed channel open at the ignition end is discussed. It is shown that, similar to the closed-end case studied earlier, the hydraulic resistance causes a gradual precompression and preheating of the unburned gas adjacent to the advancing deflagration, which leads (after an extended induction period) to a localized autoignition that triggers an abrupt transition from deflagrative to detonative combustion. In line with the experimental observations, the ignition at the open end greatly encumbers the transition (compared with the closed-end case), and the deflagration practically does not accelerate up to the very transition point. Shchelkin's effect, that ignition at a small distance from the closed end of a tube facilitates the transition, is described. PMID:22213662

Brailovsky, I; Kagan, L; Sivashinsky, G

2012-02-13

300

Hydraulically actuated artificial muscles  

NASA Astrophysics Data System (ADS)

Hydraulic Artificial Muscles (HAMs) consisting of a polymer tube constrained by a nylon mesh are presented in this paper. Despite the actuation mechanism being similar to its popular counterpart, which are pneumatically actuated (PAM), HAMs have not been studied in depth. HAMs offer the advantage of compliance, large force to weight ratio, low maintenance, and low cost over traditional hydraulic cylinders. Muscle characterization for isometric and isobaric tests are discussed and compared to PAMs. A model incorporating the effect of mesh angle and friction have also been developed. In addition, differential swelling of the muscle on actuation has also been included in the model. An application of lab fabricated HAMs for a meso-scale robotic system is also presented.

Meller, M. A.; Tiwari, R.; Wajcs, K. B.; Moses, C.; Reveles, I.; Garcia, E.

2012-04-01

301

Optimal two-degree-of-freedom fuzzy control for locomotion control of a hydraulically actuated hexapod robot  

Microsoft Academic Search

Locomotion control of legged robots is a very challenging task because very accurate foot trajectory tracking control is necessary for stable walking. An electro-hydraulically actuated walking robot has sufficient power to walk on rough terrain and carry a heavier payload. However, electro-hydraulic servo systems suffer from various shortcomings such as a high degree of nonlinearity, uncertainty due to changing hydraulic

Ranjit Kumar Barai; Kenzo Nonami

2007-01-01

302

Design of a portable hydraulic ankle-foot orthosis.  

PubMed

Small-scale hydraulics is ideal for powered human assistive devices including powered ankle foot orthoses because a large torque can be generated with an actuator that is small and light. A portable hydraulic ankle foot orthosis has been designed and is undergoing preliminary prototyping and engineering bench test evaluation. The device provides 90 Nm of ankle torque and has an operating pressure of 138 bar (2,000 psi). The battery-operated hydraulic power supply weighs about 3 kg and is worn at the waist. The ankle component weighs about 1.2 Kg and connects to the power supply with two hoses. Performance simulation and preliminary bench testing suggests that the device could be useful in certain rehabilitation applications. PMID:25570175

Neubauer, Brett C; Nath, Jonathan; Durfee, William K

2014-08-01

303

Remotely Adjustable Hydraulic Pump  

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

304

A water hydraulic robot  

Microsoft Academic Search

The design of a novel robot is outlined. The robot has three important design features: water driven hydraulics, harmonic drive gearboxes used as differentials and a planar five-bar parallelogram mechanism. The water motor\\/valve characteristics are described for a pre-prototype system and these are used in a simulation of step responses which are shown to exhibit limit cycling behaviour for small

P. M. Taylor; J. Kieffer; R. Oldaker; A. J. Wilkinson; J. M. Gilbert

1993-01-01

305

Hydraulic set and straight pull release well packer  

SciTech Connect

A well packer is described which is adapted to be set in a conduit disposed in a well bore having initially retracted packing seal means and initially retracted slip means which are set by opposing acting hydraulically actuated pistons. A single one-way clutch is connected between the pistons allowing simultaneous movement of the pistons for setting and holding the packer centrally in the conduit. A releasable sub includes an abutment member initially positioned against the top of the packing seal means with a housing telescopically surrounding and initially holding the abutment in position. An outer member is releasably connected to the housing and to a packer expander sleeve and various coacting shoulders are provided between the components whereby vertical movement upwardly of the packer housing will release the set packer.

Garner, J.K.

1981-04-28

306

Prospects for improved thermodynamic efficiency in hydraulically driven robots  

Microsoft Academic Search

Several control strategies for reducing the power consumption of fluid power servo-systems are tested by computer simulation. Results are expressed in terms of a performance ratio, which compares the power input to a controlled system with the hydraulic power input to a reference (or conventional) system. Control strategies examined use modified servo-valves and\\/or variable supply pressures (e.g., one that maintains

B. J. Howley; S. L. Dickerson

1983-01-01

307

Shearing of frictional sphere packings  

E-print Network

We measure shear response in packings of glass beads by pulling a thin, rough, metal plate vertically through a bed of volume fraction phi, which is set, before the plate is pulled, in the range 0.575 to 0.628. The yield stress is velocity independent over 4 decades and increases exponentially with phi, with a transition at phi approximately 0.595. An analysis of the measured force fluctuations indicates that the shear modulus is significantly smaller than the bulk modulus.

Jean-François Métayer; Donald J. Suntrup III; Charles Radin; Harry L. Swinney; Matthias Schröter

2011-04-19

308

Shearing of frictional sphere packings  

NASA Astrophysics Data System (ADS)

We measure shear response in packings of glass beads by pulling a thin, rough, metal plate vertically through a bed of volume fraction phi, which is set, before the plate is pulled, in the range from 0.575 to 0.628. The yield stress is velocity independent over 4 decades and increases exponentially with phi, with a transition at phi?0.595. An analysis of the measured force fluctuations indicates that the shear modulus is significantly smaller than the bulk modulus.

Métayer, J.-F.; Suntrup, D. J., III; Radin, C.; Swinney, H. L.; Schröter, M.

2011-03-01

309

Packing defects functionalize soluble proteins.  

PubMed

This work explores the participation of protein packing defects, the so-called dehydrons, in biochemical events. We delineate the enabling role of dehydrons as activators of nucleophilic groups. This activation results from the induction of chemical basicity in interfacial water molecules, promoting deprotonation of adjacent nucleophiles. Through multiple steering molecular dynamics with pulling along the proton-displacement coordinate, we show that nucleophilic groups are functionally enabled by nearby dehydrons that promote proton transference. The computations are validated against experimentally determined pKa decreases at functional sites and biochemical probes of deregulated catalytic activity arising from dehydron-generating mutations. PMID:25771861

Fernández, Ariel

2015-04-13

310

Experimental study on temperature characteristics and energy conversion in packed bed reactor with dielectric barrier discharge  

NASA Astrophysics Data System (ADS)

The temperature characteristics and energy conversion in packed bed reactor combined with a dielectric barrier discharge (DBD) plasma was investigated experimentally. The pellet temperatures of two types packed bed reactor, cylindrical reactor and parallel-plate reactor, was measured in conditions of various inlet voltage of DBD plasma. The relationship between pellet temperature of the packed bed and applied voltage of DBD plasma was discovered. The experimental result indicates a tendency that the pellet temperature of packed bed increases as the applied voltage of inlet plasma increases. When the voltage of inlet plasma is high enough, the pellet temperature increment decreases. Simultaneously,the packed bed temperature is sensitive to the inlet plasma energy and there is a potential application to heat exchanger. Moreover the proportion of energy consumption of plasma inputting into packed bed reactor was analyzed and calculated. The mechanisms that electrical energy of inlet plasma is transformed into heat energy in the two phases, gaseous and pellets of the packed bed reactor are different. The energy consumption in pellet phase is dielectric polarization loss and depends on packed bed geometry and DBD plasma etc. The energy consumption in gaseous phase is plasma sheath procedure. The important factors effecting on gas discharge are gaseous component and voltage, frequency of power.

Li, Sen; Tang, Zuchen; Gu, Fan

2010-10-01

311

The Centre for Power Transmission  

E-print Network

systems, whether for aircraft control, robotic manipulation or other multi-axis applications that limit the leakage of fluid. Friction forces are usually overcome by the hydraulic actuation capability Bois) PTO #12;5. Modelling and Development of Low Noise Hydraulic Fluid Power Systems Hydraulic fluid

Burton, Geoffrey R.

312

Low-flow hydraulic conductivity tests at wells that cross the water table.  

PubMed

Wells with screens and sand packs that cross the water table represent a challenging problem for determining hydraulic conductivity by slug testing due to sand pack drainage and resaturation. Sand pack drainage results in a multisegmented recovery curve. One must then subjectively pick a portion of the curve to analyze. Sand pack drainage also results in a change in the effective radius of the well which requires a guess at the porosity or specific yield in analyzing the test. In the study of Robbins et al. (2009), a method was introduced to obtain hydraulic conductivity in monitoring wells using the steady-state drawdown and flow rate obtained during low-flow sampling. The method was tested in this study in wells whose screens cross the water table and shown to avoid sand pack drainage problems that complicate analyzing slug tests. In applying the method to low-flow sampling, only a single pair of steady-state flow rate and drawdown are needed; hence, to derive meaningful results, an accurate determination of these parameters is required. PMID:20726899

Aragon-Jose, Alejandra T; Robbins, Gary A

2011-01-01

313

Dense packing crystal structures of physical tetrahedra  

E-print Network

We present a method for discovering dense packings of general convex hard particles and apply it to study the dense packing behavior of a one-parameter family of particles with tetrahedral symmetry representing a deformation of the ideal mathematical tetrahedron into a less ideal, physical, tetrahedron and all the way to the sphere. Thus, we also connect the two well studied problems of sphere packing and tetrahedron packing on a single axis. Our numerical results uncover a rich optimal-packing behavior, compared to that of other continuous families of particles previously studied. We present four structures as candidates for the optimal packing at different values of the parameter, providing an atlas of crystal structures which might be observed in systems of nano-particles with tetrahedral symmetry.

Yoav Kallus; Veit Elser

2010-11-17

314

Dense packing crystal structures of physical tetrahedra  

E-print Network

We present a method for discovering dense packings of general convex hard particles and apply it to study the dense packing behavior of a one-parameter family of particles with tetrahedral symmetry representing a deformation of the ideal mathematical tetrahedron into a less ideal, physical, tetrahedron and all the way to the sphere. Thus, we also connect the two well studied problems of sphere packing and tetrahedron packing on a single axis. Our numerical results uncover a rich optimal-packing behavior, compared to that of other continuous families of particles previously studied. We present four structures as candidates for the optimal packing at different values of the parameter, providing an atlas of crystal structures which might be observed in systems of nano-particles with tetrahedral symmetry.

Kallus, Yoav

2010-01-01

315

Application of smart material-hydraulic actuators  

NASA Astrophysics Data System (ADS)

The application of a new class of actuators is considered. The actuators under development combine a high energy density smart material, specifically a piezoelectric material, with internal servohydraulic components. Large displacement outputs are produced, while the high force capacity of the stiff smart material is retained, for a net high-energy output. The actuator is considered "power-by-wire" because only electrical power is provided from the vehicle or system controller. A primary motivating application is in unmanned combat air vehicles (UCAVs). The particular actuation needs of these vehicles, in flight control and other utility functions, are described and distilled to a set of relevant device requirements. Other potential applications, such as flight motion simulation, are also highlighted. The new actuation architecture offers specific advantages over centralized hydraulic systems and has capabilities not present in electromechanical actuators (EMAs). The main advantage over centralized hydraulic systems is the elimination of the need for hydraulic lines. Compared to motor-driven ball screw type EMAs, the new actuators offer higher frequency response, and a larger peak-to-average output. A laboratory test facility designed to represent the loading experienced by a UCAV control surface is described. Key steps necessary to flight qualify the actuator are introduced.

Anderson, Eric H.; Bales, Gregory L.; White, Edward V.

2003-08-01

316

Close-packing of growing discs  

SciTech Connect

Spiral lattices are derived by allowing growing discs to aggregate under a close-packing rule. Both Fibonacci and Lucas numbers of visible spirals arise naturally, dependent only on the choice of growth centre. Both the rate of convergence towards an ideal spiral, and chirality, are determined by the initial placement of the first few discs (initial conditions). Thus the appearance of spiral packings is no more or less mysterious than the appearance of hexagonal packed arrays of equal discs.

Bursill, L.A.; Xudong, F. (Melbourne Univ., Parkville (Australia). School of Physics)

1988-12-01

317

Calculator programs determine drilling hydraulics  

SciTech Connect

Two TI-59 programs were prepared for the calculation of drilling hydraulics as set forth in the Hughes Tool Co. publication, Practical Hydraulics. One presents the stepwise determination of drill string pressure drop while the second, to be published in a future issue, calculates jet area, jet velocity and impact force along with bit pressure drop and hydraulic horsepower. Another section of the second program considers pump mechanics, calculating the required strokes per minute to attain a specific circulating rate, or the circulation that would result from a specific pump speed. Hydraulic horsepower of the pump is then calculated from this rate and a maximum pump pressure.

Landry, W.E.

1987-05-01

318

Dense crystalline dimer packings of regular tetrahedra  

E-print Network

We have discovered the densest known packing of regular tetrahedra with a density phi = 4000/4671 = 0.856347.... Like the recently discovered packings of Kallus et al. [arXiv:0910.5226] and Torquato-Jiao [arXiv:0912.4210], our packing is crystalline with a unit cell of four tetrahedra forming two triangular bipyramids (dimer clusters) and is cluster transitive. The densest packing is a special case of an analytical three-parameter family of dimer packings we have constructed. The slightly lower packing densities of phi = 100/117 = 0.854700... (Kallus et al.) and phi = 12250/14319 = 0.855506... (Torquato-Jiao), obtained via analytical one-parameter and two-parameter families of dimer packings, respectively, are shown to be suboptimal cases of our more general formalism. Numerical compressions starting from random configurations confirm that the reported packing is optimal at least for small systems with up to 16 tetrahedra. For all systems with four or more tetrahedra, we obtain packings with densities higher ...

Chen, Elizabeth R; Glotzer, Sharon C

2010-01-01

319

Geometry of Frictionless and Frictional Sphere Packings  

E-print Network

We study static packings of frictionless and frictional spheres in three dimensions, obtained via molecular dynamics simulations, in which we vary particle hardness, friction coefficient, and coefficient of restitution. Although frictionless packings of hard-spheres are always isostatic (with six contacts) regardless of construction history and restitution coefficient, frictional packings achieve a multitude of hyperstatic packings that depend on system parameters and construction history. Instead of immediately dropping to four, the coordination number reduces smoothly from $z=6$ as the friction coefficient $\\mu$ between two particles is increased.

Leonardo E. Silbert; Deniz Ertas; Gary S. Grest; Thomas C. Halsey; Dov Levine

2001-11-08

320

Iterative packing for demand matching and sparse packing.  

SciTech Connect

The main result we will present is a 2k-approximation algorithm for the following 'k-hypergraph demand matching' problem: given a set system with sets of size <=k, where sets have profits & demands and vertices have capacities, find a max-profit subsystem whose demands do not exceed the capacities. The main tool is an iterative way to explicitly build a decomposition of the fractional optimum as 2k times a convex combination of integral solutions. If time permits we'll also show how the approach can be extended to a 3-approximation for 2-column sparse packing. The second result is tight w.r.t the integrality gap, and the first is near-tight as a gap lower bound of 2(k-1+1/k) is known.

Parekh, Ojas

2010-11-01

321

Hydraulic mining method  

DOEpatents

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.

Huffman, Lester H. (Kent, WA); Knoke, Gerald S. (Kent, WA)

1985-08-20

322

Modular hydraulic control system  

NASA Astrophysics Data System (ADS)

A system of modular electrohydraulic servovalves is centrally controlled and may be used to control the operation of critical hydraulic actuators. A programmable controller operates a group of modular servovalves which each deliver a portion of the total actuator fluid requirements. The flow rate, valve position, and valve pressure of each servovalve is monitored by the controller and compared to expected values in memory to determine whether a servovalve malfunction exists. If so, the controller maintains the required flow rate to the actuator by closing the malfunctioning valve and either activating a spare or proportionally increasing the flow rates of the remaining servovalves to compensate for the loss.

Winyard, David C.; Lindstrom, Waldemar C.

1994-06-01

323

110. TUBING FOR HYDRAULIC FLUID AT BACK OF HYDRAULIC CONTROL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

110. TUBING FOR HYDRAULIC FLUID AT BACK OF HYDRAULIC CONTROL PANEL IN UMBILICAL MAST PUMP ROOM (109), LSB (BLDG. 770) ACCUMULATOR FOR MAST RETRACTION ON LEFT. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

324

128. TUBING FOR HYDRAULIC FLUID AT BACK OF HYDRAULIC CONTROL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

128. TUBING FOR HYDRAULIC FLUID AT BACK OF HYDRAULIC CONTROL PANEL IN UMBILICAL MAST PUMP ROOM (209), LSB (BLDG. 751). PUMP ON RIGHT; ACCUMULATOR FOR MAST RETRACTION ON LEFT. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

325

Dynamic Modeling and Analysis of the Hydraulic System of Automotive Automatic Transmissions  

Microsoft Academic Search

This paper presents a dynamic model of the power circuits of the hydraulic system of automotive automatic transmissions. The model includes a variable-displacement vane-pump, a regulator as a load. The load may be any combination of leakage, compliance, and time-dependent hydraulic resistance. This model was used to analyze the dynamics of the hydraulic system of a conventional step-transmission under both

A. M. Karmel

1986-01-01

326

Packing density of cementitious materials: part 2—packing and flow of OPC + PFA + CSF  

Microsoft Academic Search

The wet packing method developed in Part 1 [Wong HHC, Kwan AKH (2007) Packing density of cementitious materials: part 1 measurement\\u000a using a wet packing method. Mater Struct (Paper No. MAAS3281)] has been successfully applied to measure the packing densities\\u000a of cementitious materials containing ordinary Portland cement (OPC), pulverised fuel ash (PFA) and condensed silica fume (CSF).\\u000a The test results for

A. K. H. Kwan; H. H. C. Wong

2008-01-01

327

FOREWORD: 26th IAHR Symposium on Hydraulic Machinery and Systems  

NASA Astrophysics Data System (ADS)

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 was molded into a polytechnic institute focusing on engineering in the nationwide restructuring of universities and colleges undertaken in 1952. At present, the university has 14 schools and 56 departments with faculties in science, engineering, humanities, law, medicine, history, philosophy, economics, management, education and art. The University now has over 25 900 students, including 13 100 undergraduates and 12 800 graduate students. As one of China's most renowned universities, Tsinghua has become an important institution for fostering talents and scientific research. The International Association of Hydro-Environment Engineering and Research (IAHR) particularly promotes the advancement and exchange of knowledge through working groups, specialty symposia, congresses, and publications on water resources, river and coastal hydraulics, risk analysis, energy, environment, disaster prevention, and industrial processes. The IAHR Committee on Hydraulic Machinery and Systems deals with the advancement of technology associated with the understanding of steady and unsteady flow characteristics in hydraulic machinery and conduit systems connected to the machinery. The technology elements include the fluid behaviour within machine components, hydro-elastic behaviour of machine components, cavitation and two phase flow in turbines and pumps, hydraulic machine and plant control systems, the use of hydraulic machines to improve water quality, and even considerations to improve fish survival in their passage through hydro plants. The main emphases of the IAHR Committee on Hydraulic Machinery and Systems are to stimulate research and understanding of the technologies associated with hydraulic machinery and to promote interaction between the machine designers, machine users, the academic community, and the community as a whole. Hydraulic machinery is both cost effective and environmentally friendly. The goals of the IAHR Committee on Hydraulic Machinery and Systems are to improve the value of hydraulic machinery to the end user, to the societies, and to improve societies u

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

2012-11-01

328

A 6-DOF vibration isolation system for hydraulic hybrid vehicles  

NASA Astrophysics Data System (ADS)

This paper presents the results of vibration isolation analysis for the pump/motor component of hydraulic hybrid vehicles (HHVs). The HHVs are designed to combine gasoline/diesel engine and hydraulic power in order to improve the fuel efficiency and reduce the pollution. Electric hybrid technology is being applied to passenger cars with small and medium engines to improve the fuel economy. However, for heavy duty vehicles such as large SUVs, trucks, and buses, which require more power, the hydraulic hybridization is a more efficient choice. In function, the hydraulic hybrid subsystem improves the fuel efficiency of the vehicle by recovering some of the energy that is otherwise wasted in friction brakes. Since the operation of the main component of HHVs involves with rotating parts and moving fluid, noise and vibration are an issue that affects both passengers (ride comfort) as well as surrounding people (drive-by noise). This study looks into the possibility of reducing the transmitted noise and vibration from the hydraulic subsystem to the vehicle's chassis by using magnetorheological (MR) fluid mounts. To this end, the hydraulic subsystem is modeled as a six degree of freedom (6-DOF) rigid body. A 6-DOF isolation system, consisting of five mounts connected to the pump/motor at five different locations, is modeled and simulated. The mounts are designed by combining regular elastomer components with MR fluids. In the simulation, the real loading and working conditions of the hydraulic subsystem are considered and the effects of both shock and vibration are analyzed. The transmissibility of the isolation system is monitored in a wide range of frequencies. The geometry of the isolation system is considered in order to sustain the weight of the hydraulic system without affecting the design of the chassis and the effectiveness of the vibration isolating ability. The simulation results shows reduction in the transmitted vibration force for different working cycles of the regenerative system.

Nguyen, The; Elahinia, Mohammad; Olson, Walter W.; Fontaine, Paul

2006-03-01

329

AmbiPack: A Systematic Algorithm for Packing of Macromolecular Structures With Ambiguous  

E-print Network

method to solve the packing and the assignment problems simultaneously given rigid monomer structuresAmbiPack: A Systematic Algorithm for Packing of Macromolecular Structures With Ambiguous Distance of multimers presents interesting new challenges. The structure(s) of the individual monomers must be found

Lozano-Perez, Tomas

330

14 CFR 25.1435 - Hydraulic systems.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Hydraulic systems. 25.1435 Section 25...Miscellaneous Equipment § 25.1435 Hydraulic systems. (a) Element design. Each element of the hydraulic system must be designed...

2010-01-01

331

Measurement and Modeling of Unsaturated Hydraulic Conductivity  

E-print Network

relationship between unsaturated hydraulic conductivity (K) and volumetric water content () is required techniques used to measure and model hydraulic conductivity as a function of water content, K21 Measurement and Modeling of Unsaturated Hydraulic Conductivity Kim S. Perkins United States

332

Hydraulic and Habitat Suitability Analyses Technical Memorandum  

E-print Network

Appendix D Hydraulic and Habitat Suitability Analyses Technical Memorandum #12;COPYRIGHT DECEMBER Series 2 and Pond Series 3 Hydraulic and Habitat Suitability Analyses Prepared for Bureau of Reclamation HILL, INC. III Hydraulic and Habitat Suitability Analyses

333

14 CFR 27.1435 - Hydraulic systems.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Hydraulic systems. 27.1435 Section 27.1435 Aeronautics...Equipment Safety Equipment § 27.1435 Hydraulic systems. (a) Design. Each hydraulic system and its elements must withstand,...

2010-01-01

334

14 CFR 25.1435 - Hydraulic systems.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Hydraulic systems. 25.1435 Section 25...Miscellaneous Equipment § 25.1435 Hydraulic systems. (a) Element design. Each element of the hydraulic system must be designed...

2014-01-01

335

14 CFR 29.1435 - Hydraulic systems.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Hydraulic systems. 29.1435 Section 29.1435 Aeronautics...Miscellaneous Equipment § 29.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2010-01-01

336

14 CFR 27.1435 - Hydraulic systems.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Hydraulic systems. 27.1435 Section 27.1435 Aeronautics...Equipment Safety Equipment § 27.1435 Hydraulic systems. (a) Design. Each hydraulic system and its elements must withstand,...

2013-01-01

337

14 CFR 23.1435 - Hydraulic systems.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Hydraulic systems. 23.1435 Section 23.1435 Aeronautics...Miscellaneous Equipment § 23.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2011-01-01

338

14 CFR 27.1435 - Hydraulic systems.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Hydraulic systems. 27.1435 Section 27.1435 Aeronautics...Equipment Safety Equipment § 27.1435 Hydraulic systems. (a) Design. Each hydraulic system and its elements must withstand,...

2014-01-01

339

14 CFR 29.1435 - Hydraulic systems.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Hydraulic systems. 29.1435 Section 29.1435 Aeronautics...Miscellaneous Equipment § 29.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2012-01-01

340

14 CFR 27.1435 - Hydraulic systems.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Hydraulic systems. 27.1435 Section 27.1435 Aeronautics...Equipment Safety Equipment § 27.1435 Hydraulic systems. (a) Design. Each hydraulic system and its elements must withstand,...

2012-01-01

341

14 CFR 29.1435 - Hydraulic systems.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Hydraulic systems. 29.1435 Section 29.1435 Aeronautics...Miscellaneous Equipment § 29.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2011-01-01

342

14 CFR 25.1435 - Hydraulic systems.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Hydraulic systems. 25.1435 Section 25...Miscellaneous Equipment § 25.1435 Hydraulic systems. (a) Element design. Each element of the hydraulic system must be designed...

2013-01-01

343

14 CFR 25.1435 - Hydraulic systems.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Hydraulic systems. 25.1435 Section 25...Miscellaneous Equipment § 25.1435 Hydraulic systems. (a) Element design. Each element of the hydraulic system must be designed...

2011-01-01

344

14 CFR 29.1435 - Hydraulic systems.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Hydraulic systems. 29.1435 Section 29.1435 Aeronautics...Miscellaneous Equipment § 29.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2013-01-01

345

14 CFR 23.1435 - Hydraulic systems.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Hydraulic systems. 23.1435 Section 23.1435 Aeronautics...Miscellaneous Equipment § 23.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2012-01-01

346

14 CFR 23.1435 - Hydraulic systems.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Hydraulic systems. 23.1435 Section 23.1435 Aeronautics...Miscellaneous Equipment § 23.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2013-01-01

347

14 CFR 23.1435 - Hydraulic systems.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Hydraulic systems. 23.1435 Section 23.1435 Aeronautics...Miscellaneous Equipment § 23.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2014-01-01

348

14 CFR 23.1435 - Hydraulic systems.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Hydraulic systems. 23.1435 Section 23.1435 Aeronautics...Miscellaneous Equipment § 23.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2010-01-01

349

14 CFR 25.1435 - Hydraulic systems.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Hydraulic systems. 25.1435 Section 25...Miscellaneous Equipment § 25.1435 Hydraulic systems. (a) Element design. Each element of the hydraulic system must be designed...

2012-01-01

350

14 CFR 27.1435 - Hydraulic systems.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Hydraulic systems. 27.1435 Section 27.1435 Aeronautics...Equipment Safety Equipment § 27.1435 Hydraulic systems. (a) Design. Each hydraulic system and its elements must withstand,...

2011-01-01

351

14 CFR 29.1435 - Hydraulic systems.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Hydraulic systems. 29.1435 Section 29.1435 Aeronautics...Miscellaneous Equipment § 29.1435 Hydraulic systems. (a) Design. Each hydraulic system must be designed as follows:...

2014-01-01

352

Field investigation of heat transfer in hydraulic fractures and the effect of heat transfer on fracturing fluid design  

SciTech Connect

Fracturing fluid temperature is a key variable in the design of hydraulic fracturing treatments and the formulation of fracturing fluids. Heat transfer in a hydraulic fracture dictates the fluid formulation and the concentration of chemical {open_quotes}breakers{close_quotes} used to degrade the fluid and maximize proppant pack conductivity. This paper contains the results of an investigation of heat transfer in hydraulic fractures, and documents the recording of bottomhole temperature during Piceance Basin Mesaverde fracturing treatments and during immediate flow back ({open_quotes}forced closure{close_quotes}). Bottomhole temperature was measured with a gauge set in a perforated interval, and the data shows minimal {open_quotes}cool down{close_quotes} of fracturing fluids, i.e., flow back temperatures increased rapidly to near bottomhole static temperature. Computer simulations are also presented and a fracturing fluid design methodology is suggested which balances fluid rheological requirements with degradation requirements, for maximizing proppant pack conductivity.

Craig, D.P.; Brown, T.D.; Ely, J.W.

1996-12-31

353

Water Resources: Hydraulics and Hydrology  

E-print Network

Water Resources: Hydraulics and Hydrology Interview with Margaret S. Petersen #12;This manuscript. Greenwood's interviews to appear in the series Water Resowces: Hydraulics and Hydrology. The others were of History, Headquarters, U.S. Army Corps of Engineers, Alexandria, Virginia. MARGARET So PETERSEN WATER

US Army Corps of Engineers

354

Tractor Hydraulics. A Teaching Reference.  

ERIC Educational Resources Information Center

The manual was developed to help provide a better understanding of how and why hydraulic principles serve the purposes of weight reduction, increase of physical effort, and more precise control to machines of all types. The four components that are necessary to have a workable hydraulic system--a reservoir, a pump, a valve, and a motor (cylinder)…

American Association for Vocational Instructional Materials, Athens, GA.

355

Record high wolf, Canis lupus, pack density  

USGS Publications Warehouse

This report documents a year-around wolf (Canis lupus) density of 18.2/100 m2 and summer density of 30.8/100 km2, in a northeastern Minnesota wolf pack. The previous record was a summer density of 14.1/100 km2, for a wolf pack on Vancouver Island, BC, Canada.

Mech, L.D.; Tracy, S.

2004-01-01

356

Record high Wolf, Canis lupus, pack density  

USGS Publications Warehouse

This report documents a year-around Wolf (Canis lupus) density of 18.2/100 km2 and a summer density of 30.8/100 km2, in a northeastern Minnesota Wolf pack. The previous record was a summer density of 14.1/100 km2, for a Wolf pack on Vancouver Island, British Columbia, Canada.

Mech, L.D.; Tracy, S.

2004-01-01

357

Axial effective thermal conductivities of packed beds  

Microsoft Academic Search

Experimental investigations have been carried out to measure axial effective thermal conductivities of packed beds for a number of particles and catalyst pellets. Measurements were made for three gases (air, nitrogen and carbon dioxide) in beds packed with ball bearings, copper chromite, chromia alumina, alumina hollow cylinders and alumina spheres. A glass vacuum vessel was employed for most measurements, but

M. Elsari; R. Hughes

2002-01-01

358

On packing squares into a rectangle  

Microsoft Academic Search

We prove that every set of squares with total area 1 can be packed into a rectangle of area at most 2867\\/2048=1.399…?. This improves on the previous best bound of 1.53. Also, our proof yields a linear time algorithm for finding such a packing.

Stefan Hougardy

2011-01-01

359

Is Incest Common In Gray Wolf Packs?  

NSDL National Science Digital Library

In early 2000 the Northern Prairie Wildlife Research Center posted this resource on wolves at their Website. "Is Incest Common In Gray Wolf Packs?" suggests that incest is rare in wolf packs. The resource may be downloaded as a .zip file.

Adams, Layne G.

360

Is incest common in gray wolf packs?  

Microsoft Academic Search

Wolf packs generally consist of a breeding pair and their maturing of&pring that help provision and protect pack young. Because the reproductive tenure in wolves is often short, reproductively mature offspring might replace their parents, resulting in sibling or parent-offspr ing matings. To determine the extent of incestuous pairings, we measured relatedness based on variability in 20 microsatellit e loci

Deborah Smith; Thomas Meier; Eli Geffen; L. David Mech; John W. Burch; Layne G. Adams; Robert K. Wayne

1997-01-01

361

NEW TEACHER WELCOME PACK: ELEMENTARY SCHOOL  

NSDL National Science Digital Library

Assortment of "Best-Selling" books for Elementary School Teachers. Pack includes the following books. Picture Perfect Science, Exemplary Science Grades K-4, Uncovering Student Ideas in Science, Volume 1, Using Science Notebooks, and Everyday Science Mysteries. Books are packed into a waterproof, nylon briefcase with handle and shoulder strap. Front flap of briefcase is printed with the NSTA logo.

1900-01-01

362

Softening of Granular Packings with Dynamic Forcing  

E-print Network

We perform numerical simulations of a two-dimensional bidisperse granular packing subjected to both a static confining pressure and a sinusoidal dynamic forcing applied by a wall on one edge of the packing. We measure the response experienced by a wall on the opposite edge of the packing and obtain the resonant frequency of the packing as the static or dynamic pressures are varied. Under increasing static pressure, the resonant frequency increases, indicating a velocity increase of elastic waves propagating through the packing. In contrast, when the dynamic amplitude is increased for fixed static pressure, the resonant frequency decreases, indicating a decrease in the wave velocity. This occurs both for compressional and for shear dynamic forcing, and is in agreement with experimental results. We find that the average contact number $Z_c$ at the resonant frequency decreases with increasing dynamic amplitude, indicating that the elastic softening of the packing is associated with a reduced number of grain-grain contacts through which the elastic waves can travel. We image the excitations created in the packing and show that there are localized disturbances or soft spots that become more prevalent with increasing dynamic amplitude. Our results are in agreement with experiments on glass bead packings and earth materials such as sandstone and granite, and may be relevant to the decrease in elastic wave velocities that has been observed to occur near fault zones after strong earthquakes, in surficial sediments during strong ground motion, and in structures during earthquake excitation.

C. J. Olson Reichhardt; L. M. Lopatina; X. Jia; P. A. Johnson

2014-06-17

363

Circle Packing Explorations Francesco De Comite  

E-print Network

circle packing generation becomes then: "Each time you define a new circle, fill it with a Steiner chainCircle Packing Explorations Francesco De Comit´e Laboratoire d'Informatique Fondamentale de Lille University of Sciences and Technology of Lille France Francesco.De-Comite@univ-lille1.fr Abstract Circle

Paris-Sud XI, Université de

364

Pack Density Limitations of Hybrid Parachutes  

NASA Technical Reports Server (NTRS)

The development and testing of the Orion crew capsule parachute system has provided a unique opportunity to study dense parachute packing techniques and limits, in order to establish a new baseline for future programs. The density of parachute packs has a significant influence on vibration loads, retention system stresses, and parachute mortar performance. Material compositions and pack densities of existing designs for space capsule recovery were compared, using the pack density of the Apollo main parachutes as the current baseline. The composition of parachutes has changed since Apollo, incorporating new materials such as Kevlar , Vectran , Teflon and Spectra . These materials have different specific densities than Nylon, so the densities of hybrid parachute packs cannot be directly compared to Nylon parachutes for determination of feasibility or volume allocation. Six parachute packs were evaluated in terms of weighted average solid density in order to achieve a non-dimensional comparison of packing density. Means of mitigating damage due to packing pressure and mortar firing were examined in light of the Capsule Parachute Assembly System (CPAS) and Apollo experience. Parachute design improvements including incorporation of modern materials and manufacturing processes serves to make CPAS the new knowledge base on which future spacecraft parachute systems will be built.

Zwicker, Matthew L.; Sinclair, Robert J.

2013-01-01

365

Air purification in disk-packing regenerators  

Microsoft Academic Search

The reasons for the entrainment of crystalline impurities from the packing are various. Extremely fine crystals are carried out of the generator by the sublimation of impurities frozen in the packing during the direct blast period. There is information in the literature indicating a relationship between the process of impurity accumulation in the generators and the quality of air purification

V. P. Alekseev; L. P. Danilenko; N. K. Polivalin

1981-01-01

366

Climate Change Action Pack Climate & Habitats  

E-print Network

Climate Change Action Pack Climate & Habitats B A C K G R O U DN C H E C K ! Habitat, Food, Water Change on habitats,and in particular at the impacts that could result from the warming of global the potential to affect plants,animals and humans around the globe. #12;Climate Change Action Pack 158 Habitat

Gunawardena, Arunika

367

Probe with integrated heater and thermocouple pack  

SciTech Connect

This patent describes a gamma thermometer probe for detecting heat produced within the thermometer probe. It comprises: an outer elongate thermometer sheath; an elongate rod; annular recesses; a longitudinal bore; and an integrated thermocouple pack. The thermocouple pack comprises: a first type wire, and second type wires. The second type wires comprises: an outer section; and an inner segment.

McCulloch, R.W.; Dial, R.E.; Finnell, W.F.R.

1988-02-16

368

Random Close Packings of Regular Polygons  

Microsoft Academic Search

We study by numerical simulation the progressive densification of assemblies of equal regular polygons (pentagons and heptagons). We follow the evolution of the packing fraction, of the coordination numbers and of the void space structure during the densification. At high packing fraction (Csim 0.83), ordered zones appear. This can be compared with what occurs in equal disc assemblies in which

Y. Limon Duparcmeur; J. P. Troadec; A. Gervois

1997-01-01

369

Method and tool for gravel pack evaluation  

Microsoft Academic Search

This patent describes a method for investigating a gravel pack located in the annulus between the tubing\\/screen and the casing of a borehole. It comprises: moving a logging tool through the tubing\\/screen over the depth region of the gravel pack, the logging tool including a neutron source able to emit neutrons at such an energy that their interaction with a

1990-01-01

370

Pack rats (Neotoma spp.): Keystone ecological engineers?  

Technology Transfer Automated Retrieval System (TEKTRAN)

The potential role of two species of pack rats (Neotoma albigula and Neotoma micropus) as keystone ecological engineers was examined by estimating the species diversity of invertebrates living in the nest middens, and nitrogen mineralization rates in soils associated with the middens. Although pack-...

371

7 CFR 51.630 - Standard Pack.  

Code of Federal Regulations, 2010 CFR

...specified as uniform in size. When packed in approved...Fairly uniform in size” means that not more...and II, are outside the ranges of diameters given in... Bushel Carton Pack size/number of grapefruit...and (2) 27 size and larger—not more than...

2010-01-01

372

New value packing technology extends service life  

SciTech Connect

New packing techniques can extend packing life and retain low stem leakage. The HPI can use these designs to avoid mandatory monitoring and repair schedules for valves that exceed the 500-ppm emission threshold. New EPA leakage limits will enforce monitoring and maintenance programs if more than 2% of the facility's valves exceed this limit. Because valves are dynamic, their control actions are prone to leakage. Also, the best fire-resistant packing material, graphite, has inherent deficiencies such as high compression stress and a high-friction coefficient that shortens its service life. Four basic principles overcome graphite packing's shortcomings for control valve applications. Examples show how these criteria improve sliding stem and rotary valve performance. Incorporating these principles into valve-packing designs can ensure long, low-maintenance service life, and the added benefit of low leakage. Graphite is a very important packing material for the HPI. Unlike fluoropolymer (e.g., PTFE) packing, graphite can tolerate high process temperature without decomposing or losing its sealing properties. More importantly, graphite packing is fire safe. It can survive a fire without a catastrophic failure that could add more flammable materials.

Miller, M.; Jackson, R. (Fisher Controls International, Inc., Marshalltown, IA (United States))

1993-10-01

373

Geometry of frictionless and frictional sphere packings  

Microsoft Academic Search

Dense amorphous packings of frictionless spheres have proven to be an extremely useful paradigm in a number of physical contexts including glasses, colloidal crystals, and emulsions. Granular materials are one such system, with a major difference: grain-grain interactions involve frictional forces. We investigated friction's effect on packings through extensive molecular dynamics simulations of frictionless and frictional spheres in three dimensions.

Gary Grest; Deniz Ertas; Thomas C. Halsey; Dov Levine

2002-01-01

374

Operation of Packed-Bed Reactors Studied in Microgravity  

NASA Technical Reports Server (NTRS)

The operation of a packed bed reactor (PBR) involves gas and liquid flowing simultaneously through a fixed-bed of solid particles. Depending on the application, the particles can be various shapes and sizes but are generally designed to force the two fluid phases through a tortuous route of narrow channels connecting the interstitial space. The PBR is the most common type of reactor in industry because it provides for intimate contact and high rates of transport between the phases needed to sustain chemical or biological reactions. The packing may also serve as either a catalyst or as a support for growing biological material. Furthermore, this type of reactor is relatively compact and requires minimal power to operate. This makes it an excellent candidate for unit operations in support of long-duration human space activities.

Motil, Brian J.; Balakotaiah, Vemuri

2004-01-01

375

Monument Creek hydraulics project  

NSDL National Science Digital Library

Students are given some general questions (file "IntroQuestions_07.pdf") related to project design during the class session before the main project is handed out. They need to use their textbook and/or other class resources to attempt to answer these questions and to prepare to discuss them the next class session. These questions concern field reconstruction of flood hydraulics, specifically. of bankfull flow. At this next class session we discuss their answers to the preliminary questions. Students are then given the main project handout (Monument_Ck_Problem_07.pdf). This gives them the general questions to be answered in the project. After reading it, students brainstorm again as a class about how to go about answering the questions. Students then divide themselves into research of three. These teams will synthesize data together and ultimately write up the project together. Each team then sends one member to join members of other teams to do one of the three main aspects of the field or computer work (1) field identification of the bankfull channel and measurement of bankfull channel geometry, (2) field determination of modern channel roughness from modern stream hydraulics (Manning's n is back-calculated from present channel geometry and flow), (3) development of a flood-frequency curve for this reach of Monument Creek from USGS discharge data. These working groups (with one member from each research team) work initially independently in the field and subsequently doing calculations in the lab, or on the computer. Once each working group has completed what it can do on its own, these groups split up and each member of each group carries the groups results back to his/her research team, and explains to the other members of the research team what he/she has done to this point and what results he/she has for the team. The team then works to synthesize he results into an overall answer to the questions posed at the beginning of the lab (confusing enough for you?). Each research team then writes up the results, sometimes (as in 2007) as a lab write up, in other years in scientific paper format. Whether the project is turned in simply as a lab write up or as a scientific paper, students are always asked to assess sources of error and how they might affect the results. Key words: Fluvial geomorphology, fluvial hydraulics, bankfull discharge, flood-frequency analysis Designed for a geomorphology course

Eric Leonard

376

Powered Remote Manipulators Perform Hazardous Retrieval, Handling, and Size Reduction Operations  

SciTech Connect

This paper describes a new lightweight, powered remote manipulator (PRM) that S.A.Robotics has developed for remote material handling and size reduction in hazardous environments such as reactor decommissioning projects. PRMs can be mounted to various deployment platforms such as remote controlled track-driven vehicles, commercial All Terrain Vehicles, or crane-mounted arms. They can also be installed as replacements for traditional Master-Slave Manipulators (MSMs) in hot cells. The PRM is a six degree of freedom manipulator with carbon fiber structural components that can provide up to a 3 meter (10 foot) reach. Either electric or hydraulic power options can be used and a variety of hydraulic fluids are available to meet combustible material limitations. The PRM is operated with easy-to-use joystick controls that allow operators to sit in a comfortable work station and handle 90 kg (200 pound) loads with a hydraulic power pack or 45 kg (100 pounds) with electric servo-motor driven equipment. With a quick disconnect tool changer, the manipulator can operate grippers, drills, shears, saws, sampling and survey instruments, and the arm can also deploy cameras and lights to support a wide range of remote applications. (authors)

Cole, M.D.; Owen, J.R.; Adams, S.R. [S.A.Robotics, Inc., 3985 S. Lincoln Avenue, Suite 100, Loveland, Colorado 80241 (United States)

2006-07-01

377

Hydraulic properties of coarsely and finely ground woodchips  

NASA Astrophysics Data System (ADS)

Recent evidence suggests that leachate from woodchips stockpiled at recycling facilities could negatively impact water quality. Models that can be used to simulate water movement/leachate production require information on water retention and hydraulic conductivity functions of the stockpiled material. The objectives of this study were to (1) determine water retention and hydraulic conductivity functions of woodchips with particle size distributions (PSDs) representative of field stockpiled material by modeling multistep outflow and (2) assess the performance of three pore structure models for their ability to simulate outflow. Six samples with contrasting PSDs were assessed in duplicate. Samples were packed in cylindrical columns (15.3 cm high, 12.1 cm wide) to measure saturated hydraulic conductivity (Ks), cumulative outflow and water content at equilibrium with pressure potentials of -2, -10 and -40 cm. Water retention at pressure potentials between -200 and -10,000 cm were obtained using pressure plate extractors and used to supplement data from the outflow experiment. Hydraulic parameters of the pore models were derived from these measurements using HYDRUS-1D run by DREAM(ZS). Ks was independent of PSD with values between 55 and 80 cm/h. Cumulative outflow at each pressure potential was correlated with the PSD geometric mean diameters, and was best predicted by a model having two interacting pore domains, each with separate hydraulic conductivity and water retention functions (DPeM). Unsaturated conductivities were predicted to drop on an average to 0.24 cm/h at -10 cm and 3 × 10-3 cm/h at -50 cm for the DPeM model, suggesting that water would move slowly through stockpiles except during intense rainfalls.

Subroy, Vandana; Giménez, Daniel; Qin, Mingming; Krogmann, Uta; Strom, Peter F.; Miskewitz, Robert J.

2014-09-01

378

Coalescence preference in densely packed microbubbles.  

PubMed

A bubble merged from two parent bubbles with different size tends to be placed closer to the larger parent. This phenomenon is known as the coalescence preference. Here we demonstrate that the coalescence preference can be blocked inside a densely packed cluster of bubbles. We utilized high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence events inside densely packed microbubbles with a local packing fraction of ~40%. The surface energy release theory predicts an exponent of 5 in a relation between the relative coalescence position and the parent size ratio, whereas our observation for coalescence in densely packed microbubbles shows a different exponent of 2. We believe that this result would be important to understand the reality of coalescence dynamics in a variety of packing situations of soft matter. PMID:25583640

Kim, Yeseul; Lim, Su Jin; Gim, Bopil; Weon, Byung Mook

2015-01-01

379

Coalescence preference in densely packed microbubbles  

PubMed Central

A bubble merged from two parent bubbles with different size tends to be placed closer to the larger parent. This phenomenon is known as the coalescence preference. Here we demonstrate that the coalescence preference can be blocked inside a densely packed cluster of bubbles. We utilized high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence events inside densely packed microbubbles with a local packing fraction of ~40%. The surface energy release theory predicts an exponent of 5 in a relation between the relative coalescence position and the parent size ratio, whereas our observation for coalescence in densely packed microbubbles shows a different exponent of 2. We believe that this result would be important to understand the reality of coalescence dynamics in a variety of packing situations of soft matter. PMID:25583640

Kim, Yeseul; Lim, Su Jin; Gim, Bopil; Weon, Byung Mook

2015-01-01

380

Comparative performance of a UASB reactor and an anaerobic packed-bed reactor when treating potato waste leachate  

Microsoft Academic Search

The results presented in this paper are from studies on a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor and an anaerobic packed-bed (APB) reactor treating potato leachate at increasing organic loading rates from 1.5 to 7.0gCOD\\/1\\/day. The hydraulic retention times ranged from 13.2 to 2.8 days for both reactors during the 100 days of the experiment. The maximum organic loading

W. Parawira; M. Murto; R. Zvauya; B. Mattiasson

2006-01-01

381

Hydraulic system for a ratio change transmission  

DOEpatents

Disclosed is a drive assembly (10) for an electrically powered vehicle (12). The assembly includes a transaxle (16) having a two-speed transmission (40) and a drive axle differential (46) disposed in a unitary housing assembly (38), an oil-cooled prime mover or electric motor (14) for driving the transmission input shaft (42), an adapter assembly (24) for supporting the prime mover on the transaxle housing assembly, and a hydraulic system (172) providing pressurized oil flow for cooling and lubricating the electric motor and transaxle and for operating a clutch (84) and a brake (86) in the transmission to shift between the two-speed ratios of the transmission. The adapter assembly allows the prime mover to be supported in several positions on the transaxle housing. The brake is spring-applied and locks the transmission in its low-speed ratio should the hydraulic system fail. The hydraulic system pump is driven by an electric motor (212) independent of the prime mover and transaxle.

Kalns, Ilmars (Northville, MI)

1981-01-01

382

Integrated modeling of an electro-hydraulic servo manipulator using linear graphs  

Microsoft Academic Search

Analysis and design of mechatronic systems require integrated and concurrent tools. This paper presents an integrated mechatronic modeling tool using linear graphs (LG) theory. To demonstrate the capabilities of the presented framework, an integrated model of a complex electro-hydraulic servo manipulator and its governing motion equations in the state space form are presented. It includes a hydraulic power supply unit,

M. Ganji; S. Behbahani; C. W. de Silva

2010-01-01

383

AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT X, AUTOMATIC TRANSMISSIONS--HYDRAULIC SYSTEMS (PART II).  

ERIC Educational Resources Information Center

THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO PROVIDE A SUMMARY OF MAINTENANCE PROCEDURES FOR AUTOMATIC TRANSMISSIONS USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) CHECKING THE HYDRAULIC SYSTEM, (2) SERVICING THE HYDRAULIC SYSTEM, (3) EXAMINING THE RANGE CONTROL VALVE, (4) EXAMINING THE LOCK-UP AND FLOW VALVE, (5) EXAMINING THE MAIN REGULATOR…

Human Engineering Inst., Cleveland, OH.

384

Performance evaluation of a refitted hydraulic press using for water hyacinth dewatering  

Microsoft Academic Search

This article describes the design and construction of a refitted hydraulic press used for water hyacinth dewatering. The performance under different pressures of the press was investigated. The press system mainly composed five parts: support frame, round press plates, cylindrical sieve vessel, collection bucket and hydraulic power system. When the pressure increased from 10 MPa to 35 MPa, the residues

Xu Dayong

2010-01-01

385

Continuously variable transmission hydraulic control system having two pressure regulating valves  

Microsoft Academic Search

A hydraulic control system is described for a continuously variable transmission having first and second variable-diameter pulleys provided on a first and a second shafts, a transmission belt connecting the first and second pulleys to transmit power from one of the first and second pulleys to the other, and a pair of hydraulic cylinders for changing an effective diameter of

D. Sawada; M. Sugaya; Y. Soga; R. Imai

1987-01-01

386

29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.  

Code of Federal Regulations, 2012 CFR

...Labor 8 2012-07-01 2012-07-01 false Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section...CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General...

2012-07-01

387

29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.  

Code of Federal Regulations, 2011 CFR

...Labor 8 2011-07-01 2011-07-01 false Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section...CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General...

2011-07-01

388

29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.  

Code of Federal Regulations, 2014 CFR

...Labor 8 2014-07-01 2014-07-01 false Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section...CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General...

2014-07-01

389

29 CFR 1926.305 - Jacks-lever and ratchet, screw, and hydraulic.  

Code of Federal Regulations, 2013 CFR

...Labor 8 2013-07-01 2013-07-01 false Jacks-lever and ratchet, screw, and hydraulic. 1926.305 Section...CONSTRUCTION Tools-Hand and Power § 1926.305 Jacks—lever and ratchet, screw, and hydraulic. (a) General...

2013-07-01

390

Numerical prediction of erosion on guide vanes and in labyrinth seals in hydraulic turbines  

Microsoft Academic Search

Erosion in hydraulic power plants is caused by sand particles in the flow. This is one of the major problems that restricts the lifetime between overhauls of water turbines. Especially those parts of the hydraulic turbine which are exposed to high flow velocities bear a considerable risk of being damaged by erosion processes. Therefore, suitable methods for the prediction of

Reiner Mack; Peter Drtina; Egon Lang

1999-01-01

391

MECHATRONIC APPROACH FOR DESIGN AND CONTROL OF A HYDRAULIC 3DOF PARALLEL ROBOT  

Microsoft Academic Search

Modern machine tools based on parallel kinematic architecture provide excellent performance in terms of stiffness\\/weight ratio. Also, hydraulic actuators are widely used in industrial applications due to several advantages like large force and torque, high power to weight ratio, rapid response. The current paper presents the mechatronic design of a translational 3-DOF parallel robot which uses three hydraulic actuators to

R. BALAN; S. STAN; C. LAPUSAN

2007-01-01

392

Grain packing resistance to particle mobility  

NASA Astrophysics Data System (ADS)

We report the first measurements of grain packing resistance to particle motion. Packing resistance was resolved as the difference between the total resistance acting on individual grains (measured with a load cell) and the resistance that occurs when grains interact with the geometry of their resting pocket (measured with a tilt board). Because paired measurements were not available, Monte Carlo simulations were conducted to develop distributions of packing resistance from observed distributions of total and pocket angle resistance. Expressed as coefficients of friction, grain packing increased with decreasing grain size and was close to 18 times higher for smaller grains (22.6 for the 5.7 mm size class) than larger grains (1.5 for the 22.6 mm size class) because small grains tend to be more embedded, which increases the extent of packing by surrounding grains. Grain weight is included in the packing resistance force, which increased with grain size from 5 grams-force to over 98 grams-force, and was the dominant form of resistance to grain motion, exceeding pocket angle resistance by up to 88%. Percentiles of packing forces and packing coefficients of friction diverge from common origins as a function of relative grain size (Di/D50). Packing force percentiles can be expressed as a function of grain size, embeddedness, and the standard deviation of grain sizes on the bed surface (sorting), which collectively control the friction surface area of the grain. Including packing in calculations of critical bed shear stress increased thresholds of grain motion by 8 to 46% (21% average) over that calculated with pocket angles of resistance alone. This has significant implications for bed load transport predictions, which are typically nonlinear functions of the difference between applied and critical shear stresses; as such, small differences in critical shear stress can cause large prediction errors. Given the importance of packing resistance, future studies are warranted to better understand the physical and biological controls on packing, as well as the mechanics of packing resistance.

Buxton, T.; Yager, E.; Buffington, J. M.; Hassan, M. A.; Fremier, A. K.

2013-12-01

393

A tracer study for assessing the interactions between hydraulic retention time and transport processes in a wetland system for nutrient removal  

Microsoft Academic Search

In this study, a new-generation subsurface upflow wetland (SUW) system packed with the unique sorption media was introduced\\u000a for nutrient removal. To explore the interface between hydraulic and environmental performance, a tracer study was carried\\u000a out in concert with a transport model to collectively provide hydraulic retention time (7.1 days) and compelling evidence\\u000a of pollutant fate and transport processes. Research findings

Ni-Bin Chang; Zhemin Xuan; Martin P. Wanielista

394

Laboratory imaging of stimulation fluid displacement from hydraulic fractures  

SciTech Connect

Laboratory experiments were conducted to physically investigate the processes governing stimulation fluid displacement from hydraulic fractures. Experiments were performed on two scales: meter-scale in a 1500 cm{sup 2} sand pack and core-scale in a 65 cm{sup 2} API linear conductivity cell. High-resolution light transmission imaging was employed at the meter-scale to visualize and quantify processes governing fluid displacement. For comparison, complimentary tests were performed using an API conductivity cell under ambient test conditions and at elevated closure stress. In these experiments viscous fingering and gravity drainage were identified as the dominant processes governing fluid displacement. Fluid viscosity was found to dictate the relative importance of the competing displacement processes and ultimately determine the residual liquid saturation of the sand pack. The process by which fluid displacement occurs was seen to effect the shape of both the gas and liquid phase relative permeability functions. Knowledge of such viscosity/relative permeability relationships may prove useful in bounding predictions of post-stimulation recovery of gels from the fracture pack.

Tidwell, V. [Sandia National Lab., Albuquerque, NM (United States); Parker, M. [SPE, Richardson, TX (United States)

1996-11-01

395

Hydraulic conductivity of compacted zeolites.  

PubMed

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 (?(dmax)) of fine zeolite was greater than that of granular zeolites. The ?(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 ?(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. PMID:23460541

Oren, A Hakan; Ozdamar, Tu?çe

2013-06-01

396

Fluid Power  

NSDL National Science Digital Library

Hydraulics and pneumatics are both forms of fluid power, a common means of driving and controlling mechanical motions. It is one of the three kinds of power, with the other two being mechanical and electrical. Fluid power systems are widely used in most machinery, such as automobiles and construction equipment.The National Fluid Power Association (1) has an excellent introduction to the topic, which includes a general overview and descriptions of over 20 practical applications. It also looks at the current state of fluid power technology and how it has progressed in recent years. For a more detailed discussion of fluid power principles and how hydraulic and pneumatic devices operate, Integrated Publishing (2) offers twelve chapters of material, complete with diagrams. Fluid Power Web (3) is a comprehensive source of information about components, vendors, and software. Ideas and Applications is an especially interesting section, as it periodically gives a new article about clever, innovative ways of using fluid power systems. Every two months, the Fluid Power Society (4) publishes a journal with a few articles about industry news and trends. Three specialized issues are offered each year, and there is an archive with issues that date back to 1998. A complete hydraulics system is broken down into its constituent parts and explained at this Web site (5). The author uses many drawings and animations to illustrate the physical processes involved in hydraulics. The Institute of Hydraulics and Automation (6), located at the University of Tampere in Finland, has a very active research program with many focus areas. Telerobotics, mobile hydraulics, cavitation, and virtual testing are all investigated at the institute, and project descriptions in each of these areas are given on the site. The Division of Fluid Power Technology (7) at a Swedish university has developed a digital simulation tool for fluid power system design. Called HOPSAN, the software can be freely downloaded from the Web site to run on the Windows operating system (a Fortran compiler is required for Windows 95 and newer). Students at Purdue University (8) have recently built "what is thought to be the first vehicle that uses water in all of its hydraulic systems." This article highlights the students' achievement and considers the rationale behind this original design.

Leske, Cavin.

2002-01-01

397

Continuously variable transmission hydraulic control system having two pressure regulating valves  

SciTech Connect

A hydraulic control system is described for a continuously variable transmission having first and second variable-diameter pulleys provided on a first and a second shafts, a transmission belt connecting the first and second pulleys to transmit power from one of the first and second pulleys to the other, and a pair of hydraulic cylinders for changing an effective diameter of the pulleys engaging the belt. The hydraulic control system consists of: a hydraulic source delivering a pressurized fluid; a first pressure regulating device for regulating the pressurized fluid to apply a first line pressure to one of the hydraulic cylinders for controlling a tension of the transmission belt; flow control means for controlling flow of the fluid into the other hydraulic cylinder and flow of the fluid from the other hydraulic cylinder, thereby changing the effective diameters of the pulleys to vary a speed ratio of the transmission; a second pressure regulating device provided between the hydraulic source and the first pressure regulating device, and regulating the pressurized fluid to apply a second line pressure to the flow control means, the second line pressure being higher than a pressure in the other hydraulic cylinder or the first line pressure by a predetermined value; and releasing means for releasing the second pressure regulating device from its pressure regulating operation while the speed ratio of the transmission is changed with the fluid discharged from the other hydraulic cylinder, or while the speed ratio is held constant.

Sawada, D.; Sugaya, M.; Soga, Y.; Imai, R.

1987-08-11

398

Internal packing of helical membrane proteins  

PubMed Central

Helix packing is important in the folding, stability, and association of membrane proteins. Packing analysis of the helical portions of 7 integral membrane proteins and 37 soluble proteins show that the helices in membrane proteins have higher packing values (0.431) than in soluble proteins (0.405). The highest packing values in integral membrane proteins originate from small hydrophobic (G and A) and small hydroxyl-containing (S and T) amino acids, whereas in soluble proteins large hydrophobic and aromatic residues have the highest packing values. The highest packing values for membrane proteins are found in the transmembrane helix–helix interfaces. Glycine and alanine have the highest occurrence among the buried amino acids in membrane proteins, whereas leucine and alanine are the most common buried residue in soluble proteins. These observations are consistent with a shorter axial separation between helices in membrane proteins. The tight helix packing revealed in this analysis contributes to membrane protein stability and likely compensates for the lack of the hydrophobic effect as a driving force for helix–helix association in membranes. PMID:10823938

Eilers, Markus; Shekar, Srinivasan C.; Shieh, Ted; Smith, Steven O.; Fleming, Patrick J.

2000-01-01

399

Perchlorate remediation using packed-bed bioreactors and electricity generation in microbial fuel cells (MFCs)  

NASA Astrophysics Data System (ADS)

Two pilot-scale fixed bed bioreactors were operated in continuous mode in order to treat groundwater contaminated by perchlorate. The bioreactors were constructed and operated side-by-side at the Texas Street Well Facility in Redlands, California. Each reactor was packed with either sand or plastic media. A perchlorate-reducing bacterium, Dechlorosoma sp. KJ, was used to inoculate the bioreactors. Perchlorate was successfully removed down to a non-detectable level (<4mug/L) in both bioreactors with acetate as a carbon source and nutrients at loading rates less than 0.063 L/s (1 gpm; 0.34 L/m2s). The sand medium bioreactor could achieve complete-perchlorate removal up to flow rate of 0.126 L/s. A regular backwashing cycle (once a week) was an important factor for completely removing perchlorate in groundwater. Power generation directly from pure or mixed organic matter was examined using microbial fuel cells (MFCs), which were run either in batch or continuous mode. In batch experiments, both a pure culture (Geobactor metallireducens) and a mixed culture (wastewater inoculum) were used as the biocatalyst, and acetate was added as substrate in the anode chamber of the MFC. Power output in a membrane MFC with either inoculum was essentially the same, with 40 +/- 1 mW/m2 for G. metallireducens and 38 +/- 1 mW/m2 for mixed culture. A different type of the MFC containing a salt bridge instead of a membrane system was examined to generate power using the same substrate and pure culture as used in the membrane MFC. Power output in the salt bridge MFC was 2.2 mW/m 2. It was found that the lower power output was directly attributed to the higher internal resistance of the salt bridge system (19920 +/- 50 O) in comparison with that of the membrane system (1286 +/- 1 O). Continuous electricity generation was examined in a flat plate microbial fuel cell (FPMFC) using domestic wastewater and specific organic substrates. The FPMFC, containing a combined electrode/proton exchange membrane (PEM), was initially acclimated for one month to domestic wastewater, and then was operated as a plug flow reactor system. Power density using domestic wastewater as a substrate was 72 +/- 1 mW/m2 at a liquid flow rate of 0.39 mL/min (1.1 hr hydraulic retention time, HRT), and COD removal was 42%. At a longer HRT of 4.0 hr, the COD removal increased to 79%, and power density was 43 mW/m2. Several organic compounds (about 1000 mg-COD/L) also generated high power densities including: glucose (212 +/- 2 mW/m2), acetate (286 +/- 3 mW/m2), butyrate (220 +/- 1 mW/m2), dextran (150 +/- 1 mW/m 2), and starch (242 +/- 3 mW/m2). Therefore, it was shown that power could be successfully generated in a continuous-mode MFC with a variety of organic substrates. Animal wastewater was also tested as substrate to generate power in an air-cathode single chamber MFC operated in batch mode. This preliminary experiment demonstrated that power generation could be sustained with animal wastewater and that wastewater strength and odors were substantially reduced in the reactor after only one day of operation.

Min, Booki

400

Modular Approach for Continuous Cell-Level Balancing to Improve Performance of Large Battery Packs: Preprint  

SciTech Connect

Energy storage systems require battery cell balancing circuits to avoid divergence of cell state of charge (SOC). A modular approach based on distributed continuous cell-level control is presented that extends the balancing function to higher level pack performance objectives such as improving power capability and increasing pack lifetime. This is achieved by adding DC-DC converters in parallel with cells and using state estimation and control to autonomously bias individual cell SOC and SOC range, forcing healthier cells to be cycled deeper than weaker cells. The result is a pack with improved degradation characteristics and extended lifetime. The modular architecture and control concepts are developed and hardware results are demonstrated for a 91.2-Wh battery pack consisting of four series Li-ion battery cells and four dual active bridge (DAB) bypass DC-DC converters.

Muneed ur Rehman, M.; Evzelman, M.; Hathaway, K.; Zane, R.; Plett, G. L.; Smith, K.; Wood, E.; Maksimovic, D.

2014-10-01

401

Integral packing of trees and branchings  

SciTech Connect

This article continues the discussion of the author`s results on strictly polynomial algorithms for network strength problems (it is assumed that the reader is familiar with the previous publications). It considers the problem of optimal integral packing of spanning trees in a graph and proposes a strictly polynomial algorithm for the solution of this problem. The spanning tree packing and network covering algorithms described produce noninteger solutions. However, the Tutte-Nash-Williams theorem provides a good characterization for the solution of the corresponding problems for trees with integral cardinalities. Interger solutions can be obtained by Cunningham`s general algorithm, which produces an integer solution for the problem of packing of bases of a polymatroid polyhedron. This algorithm, however, is characterized by high time complexity. Moreover, the number of packed bases (in our case, spanning trees) in Seriver`s modification is double the theoretical minimum. In this paper, we apply the results to propose on O(n{sup 2} mp) algorithm for the problem of integral packing of spanning trees, where n and m respectively are the number of vertices and edges in the graph G and p is the time complexity of the maximum flow problem on G. The algorithm constructs a basis solution, so that the optimal solution contains a minimum number of spanning trees of nonzero cardinalities. In other words, the number of nonzero components forming the optimal packing does not exceed n. The proposed algorithm is easily modified for the solution of problems of minimum integral packing and covering described elswhere, and its elaboration for the present case is left to the reader. The spanning tree packing problem is transformed into a similar problem for digraphs, specifically, the problem of packing branchings into a given digraph with a distinguished root. A good characterization of this problem is provided by the Edmonds theorem.

Trubin, V.A.

1995-09-01

402

Electrokinetic high pressure hydraulic system  

DOEpatents

A compact high pressure hydraulic pump having no moving mechanical parts for converting electric potential to hydraulic force. The electrokinetic pump, which can generate hydraulic pressures greater than 2500 psi, can be employed to compress a fluid, either liquid or gas, and manipulate fluid flow. The pump is particularly useful for capillary-base systems. By combining the electrokinetic pump with a housing having chambers separated by a flexible member, fluid flow, including high pressure fluids, is controlled by the application of an electric potential, that can vary with time.

Paul, Phillip H. (Livermore, CA); Rakestraw, David J. (Fremont, CA)

2000-01-01

403

Calculator programs determine drilling hydraulics  

SciTech Connect

This paper describes Hydraulics II, which is prepared for the calculation of bit hydraulics and pump performance on the TI-59 using a PC-100C printer. The operator is prompted for the required input data with a printed register number and an abbreviated title. Output is printed and labeled. As in Hydraulics I, three magnetic cards are required, two for the program and the third for the alphanumeric memory of the prompts and output labels. Lines 000 through 100 are the same in both of these programs. The alphanumerics are stored in registers 31 through 53. The machine is partitioned 479.59.

Landry, W.E.

1987-06-01

404

Changes in entrapped gas content and hydraulic conductivity with pressure.  

PubMed

Water table fluctuations continuously introduce entrapped air bubbles into the otherwise saturated capillary fringe and groundwater zone, which reduces the effective (quasi-saturated) hydraulic conductivity, K(quasi), thus impacting groundwater flow, aquifer recharge and solute and contaminant transport. These entrapped gases will be susceptible to compression or expansion with changes in water pressure, as would be expected with water table (and barometric pressure) fluctuations. Here we undertake laboratory experiments using sand-packed columns to quantify the effect of water table changes of up to 250 cm on the entrapped gas content and the quasi-saturated hydraulic conductivity, and discuss our ability to account for these mechanisms in ground water models. Initial entrapped air contents ranged between 0.080 and 0.158, with a corresponding K(quasi) ranging between 2 and 6 times lower compared to the K(s) value. The application of 250 cm of water pressure caused an 18% to 26% reduction in the entrapped air content, resulting in an increase in K(quasi) by 1.16 to 1.57 times compared to its initial (0 cm water pressure) value. The change in entrapped air content measured at pressure step intervals of 50 cm, was essentially linear, and could be modeled according to the ideal gas law. Meanwhile, the changes in K(quasi) with compression-expansion of the bubbles because of pressure changes could be adequately captured with several current hydraulic conductivity models. PMID:22320934

Marinas, Maricris; Roy, James W; Smith, James E

2013-01-01

405

Leadership in wolf, Canis lupus, packs  

USGS Publications Warehouse

I examine leadership in Wolf (Canis lupus) packs based on published observations and data gathered during summers from 1986 to 1998 studying a free-ranging pack of Wolves on Ellesmere Island that were habituated to my presence. The breeding male tended to initiate activities associated with foraging and travel, and the breeding female to initiate, and predominate in, pup care and protection. However, there was considerable overlap and interaction during these activities such that leadership could be considered a joint function. In packs with multiple breeders, quantitative information about leadership is needed.

Mech, L.D.

2000-01-01

406

Modeling of subsidence and stress-dependent hydraulic conductivity for intact and fractured porous media  

NASA Astrophysics Data System (ADS)

This study investigates the changes in deformation and stress dependent hydraulic conductivities that occur as a result of underground mining in intact and fractured porous media. The intact porous medium is assumed to be comprised of regularly packed spherical grains of uniform size. The variation in grain size or pore space due to the effect of changing intergranular stresses results in a change in rock hydraulic conductivity. A model is developed to describe the sensitivity of hydraulic conductivity to effective stresses through Hertzian contact of spherical grains. The fractured porous medium is approximated as an equivalent fracture network in which a single fracture is idealized as a planar opening having a constant equivalent thickness or aperture. Changes in fracture aperture as a result of changes in elastic deformation control the variation of hydraulic conductivity. A model is presented to illustrate the coupling between strain and hydraulic conductivity. Subsidence induced deformations that result from mining induced changes in hydraulic conductivity in both intact and fractured media. These changes are examined and compared with results from a mining case study.

Bai, M.; Elsworth, D.

1994-10-01

407

Model-based remote handling with the MAESTRO hydraulic manipulator  

Microsoft Academic Search

A powerful hydraulic manipulator may be a useful tool to deal efficiently with the remote handling, dexterous operations required during the Divertor maintenance. Its main advantages are a good weight capacity, the large range of tasks that can be addressed and its capability to recover from unforeseen situations. On the other hand, it implies intensive video monitoring and the use

Philippe Gravez; C. Leroux; M. Irving; L. Galbiati; A. Raneda; M. Siuko; D. Maisonnier; J. D. Palmer

2003-01-01

408

Fault diagnosis of water hydraulic actuators under some simulated faults  

Microsoft Academic Search

Water hydraulics captured the imagination of engineers some 2500 years ago and recently it has revived to become a powerful alternative in areas where the environment and health are of great concern. Previously, this field of knowledge suffered some setbacks as technology was still at its developing stage, but with better tolerances and the availability of better materials, this technology

Alfred C. H. Tan; Patrick S. K. Chua; G. H. Lim

2003-01-01

409

Development of a miniaturised hydraulic actuation system for artificial hands  

Microsoft Academic Search

This article will present a powerful miniaturised hydraulic system of compact design that is used for the actuation of artificial hands. This system was developed as an alternative to today's commonly used electromechanical prosthetic actuation systems. System components and hand prototypes reflect many years of experience of our laboratory in rehabilitation medicine, CAD design and prototyping, mechanical engineering, electronic construction,

A. Kargov; T. Werner; C. Pylatiuk; S. Schulz

2008-01-01

410

Analysis of Small-Scale Hydraulic Actuation Jicheng Xia  

E-print Network

of force and power while at the same time being relatively light weight compared to the equivalent to an equivalent electromechanical system comprised of off-the-shelf components. Calculation results revealed that high operating pressures are needed for small-scale hydraulics to be lighter than the equivalent

Durfee, William K.

411

Design of hydraulic output Stirling engine  

Microsoft Academic Search

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

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

1983-01-01

412

Hydraulic control unit for automotive transmissions  

Microsoft Academic Search

This patent describes a hydraulic control unit for use in an automotive transmission having a speed change gear and a clutch, the hydraulic control unit including a housing, a change gear operating mechanism means for hydraulically operating the speed change gear, and a clutch operating mechanism means for hydraulically operating the clutch. The change gear operating mechanism means and the

Y. Kojima; H. Ishida

1986-01-01

413

Combined hydraulic and regenerative braking system  

Microsoft Academic Search

A combined hydraulic and regenerative braking system and method for an electric vehicle is disclosed. The braking system is responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially

R. R. Venkataperumal; G. E. Mericle

1979-01-01

414

Combined hydraulic and regenerative braking system  

Microsoft Academic Search

A combined hydraulic and regenerative braking system and method is disclosed for an electric vehicle. The braking system being responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially

G. E. Mericle; R. R. Venkataperumal

1981-01-01

415

Combined hydraulic and regenerative braking system  

Microsoft Academic Search

A combined hydraulic and regenerative braking system and method for an electric vehicle, with the braking system being responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially regenerative

Rama R. Venkataperumal; Gerald E. Mericle

1981-01-01

416

A Hermite cubic collocation scheme for plane strain hydraulic fractures Department of Mathematics, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z2  

E-print Network

A Hermite cubic collocation scheme for plane strain hydraulic fractures A. Peirce Department Accepted 13 February 2010 Available online 4 March 2010 Keywords: Hydraulic fractures Integro the propagation of a hydraulic fracture in a state of plane strain. Special blended cubic Hermite-power­law basis

Peirce, Anthony

417

A Hermite cubic collocation scheme for plane strain hydraulic fractures Department of Mathematics, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z2  

E-print Network

A Hermite cubic collocation scheme for plane strain hydraulic fractures A. Peirce Department Accepted 13 February 2010 Available online xxxx Keywords: Hydraulic fractures Integro-partial differential of a hydraulic fracture in a state of plane strain. Special blended cubic Hermite-power­law basis functions

Peirce, Anthony

418

Hydraulic drive system prevents backlash  

NASA Technical Reports Server (NTRS)

Hydraulic drive system uses a second drive motor operating at reduced torque. This exerts a relative braking action which eliminates the normal gear train backlash that is intolerable when driving certain heavy loads.

Acord, J. D.

1965-01-01

419

Hydraulic tests of emergency cooling system: L-Area  

SciTech Connect

The delay in L-Area startup provided an opportunity to obtain valuable data on the Emergency Cooling System (ECS) which will permit reactor operation at the highest safe power level. ECS flow is a major input to the FLOOD code which calculates reactor ECS power limits. The FLOOD code assesses the effectiveness of the ECS cooling capacity by modeling the core and plenum hydraulics under accident conditions. Presently, reactor power is not limited by the ECS cooling capacity (power limit). However, the manual calculations of ECS flows had been recently updated to include piping changes (debris strainer, valve changes, pressure release systems) and update fitting losses. Both updates resulted in reduced calculated ECS flows. Upon completion of the current program to update, validate, and document, reactor power may be limited under certain situations by ECS cooling capacity for some present reactor charge designs. A series of special hydraulic tests (Reference 1, 3) were conducted in L-Area using all sources of emergency coolant including the ECS pumps (Reference 2). The tests provided empirical hydraulic data on the ECS piping. These data will be used in computer models of the system as well as manual calculations of ECS flows. The improved modeling and accuracy of the flow calculations will permit reactor operation at the highest safe power level with respect to an ECS power limit.

Hinton, J H

1988-01-01

420

Indirect Adaptive Robust Control of Electro-Hydraulic Systems Driven by Single-Rod Hydraulic Actuator  

E-print Network

Indirect Adaptive Robust Control of Electro-Hydraulic Systems Driven by Single-Rod Hydraulic) of electro-hydraulic systems driven by single- rod hydraulic actuators. Unlike the tracking that the proposed IARC achieves good tracking performance and accurate parameter estimation. INTRODUCTION Electro-hydraulic

Yao, Bin

421

Numerical simulation of hydraulic fracturing  

E-print Network

NUMERICAL SIMULATION OF HYDRAULIC FRACTURING A Thesis by JOSEPH BARNES WARNER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1987 Maj or Subj ect...: Petroleum Engineering NUMERICAL SIMULATION OF HYDRAULIC FRACTURING A Thesis by JOSEPH BARNES WARNER Approved as to style and content by: S. A. Holditch (Chairman of Committee) D. D. Van Fleet (member) J. E. Russell (m be ) W. D. Von onten ( ead...

Warner, Joseph Barnes

1987-01-01

422

Prevention and suppression of metal packing fires.  

PubMed

Structured packing has been widely used because of large surface area that makes possible columns with high capacity and efficiency. The large surface area also contributes to fire hazards because of hydrocarbon deposits that can easily combust and promote combustion of the thin metal packing materials. Materials of high surface area that can fuel fires include reactive metals, such as titanium, and materials that are not considered combustible, such as stainless steel. Column design and material selection for packing construction is discussed together with employee training and practices for safe column maintenance and operations. Presented also are methods and agents for suppression of metal fires. Guidance for prevention and suppression of metal fires is related to incidents involving packing fires in columns. PMID:14602413

Roberts, Mark; Rogers, William J; Sam Mannan, M; Ostrowski, Scott W

2003-11-14

423

Extension of Pack Method for Compressive Tests  

NASA Technical Reports Server (NTRS)

The pack method for determining compressive stress-strain graphs described in NACA Report No. 649 has been modified to extend it's application to thinner gages and stronger materials. The principal modifications consisted in the provision of additional support against instability cementing the specimens of the pack together with fused shellac and the provision of special clamps to hold the specimens together while the test is in progress. The shellac was found to increase the buckling load of the pack without any appreciable effect on the compressive stress-strain graph of the material. The extended pack method described in this note has made possible the application of stresses in excess of 220 kips per square inch to sheet material having a thickness of only 0.02 inch.

Aitchison, C S

1940-01-01

424

Similarity of wet granular packing to gels  

NASA Astrophysics Data System (ADS)

To date, there is still no general consensus on the fundamental principle that governs glass transition. Colloidal suspensions are ordinarily utilized as model systems to study the dynamical arrest mechanisms in glass or gels. Here, we tackle the problem using athermal granular particles. Slow dynamics and structural evolution of granular packing upon tapping are monitored by fast X-ray tomography. When the packing are wet and short-range attractive interactions exist, we find a large amount of locally favoured structures with fivefold symmetry, which bear great structural similarity to colloidal gels. In addition, these structures are almost absent in dry packing with similar packing fractions. The study leads strong support for the geometrical frustration mechanism for dynamic arrest in both thermal and athermal systems with attractive interactions. It also suggests nontrivial structural mechanism, if exists, for dynamic arrest in systems with purely repulsive interactions.

Li, Jindong; Cao, Yixin; Xia, Chengjie; Kou, Binquan; Xiao, Xianghui; Fezzaa, Kamel; Wang, Yujie

2014-09-01

425

Groundwater well with reactive filter pack  

DOEpatents

A method and apparatus are disclosed for the remediation of contaminated soil and ground water wherein a reactive pack material is added to the annular fill material utilized in standard well construction techniques. 3 figs.

Gilmore, T.J.; Holdren, G.R. Jr.; Kaplan, D.I.

1998-09-08

426

7 CFR 29.3538 - Packing.  

Code of Federal Regulations, 2011 CFR

...AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3538 Packing. A lot of tobacco...

2011-01-01

427

7 CFR 29.3538 - Packing.  

Code of Federal Regulations, 2010 CFR

...AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3538 Packing. A lot of tobacco...

2010-01-01

428

Geometrical families of mechanically stable granular packings  

E-print Network

We enumerate and classify nearly all of the possible mechanically stable (MS) packings of bidipserse mixtures of frictionless disks in small sheared systems. We find that MS packings form continuous geometrical families, where each family is defined by its particular network of particle contacts. We also monitor the dynamics of MS packings along geometrical families by applying quasistatic simple shear strain at zero pressure. For small numbers of particles (N 16, we observe an increase in the period and random splittings of the trajectories caused by bifurcations in configuration space. We argue that the ratio of the splitting and contraction rates in large systems will determine the distribution of MS-packing geometrical families visited in steady-state. This work is part of our long-term research program to develop a master-equation formalism to describe macroscopic slowly driven granular systems in terms of collections of small subsystems.

Guo-Jie Gao; Jerzy Blawzdziewicz; Corey S. O'Hern

2009-09-03

429

A Versatile, Automatic Chromatographic Column Packing Device  

ERIC Educational Resources Information Center

Describes an inexpensive apparatus for packing liquid and gas chromatographic columns of high efficiency. Consists of stainless steel support struts, an Automat Getriebmotor, and an associated three-pulley system capable of 10, 30, and 300 rpm. (MLH)

Barry, Eugene F.; And Others

1977-01-01

430

Densification of the packing structure under vibrations  

NASA Astrophysics Data System (ADS)

Two packing structures with the maximum packing densities of 0.64 and 0.74 for the amorphous state and crystalline state, respectively, were numerically reproduced in the packing densification of equal spheres subjected to onedimensional and three-dimensional vibrations using the discrete element method (DEM), and the results were physically validated. These two packing structures were analyzed in terms of coordination number (CN), radial distribution function (RDF), angular distribution function (ADF), and pore size distribution (Voronoi/Delaunay tessellation). It is shown that CN distributions have the peak values of 7 and 12 for the amorphous state and crystalline state, respectively. RDF and ADF distributions show isolated peaks and orientation preferences for the crystalline state, indicating the long range and angle correlation among particles commonly observed in the crystalline state. Voronoi/Delaunay tessellation also shows smaller and narrower pore size distribution for the crystalline state.

An, Xi-zhong

2013-05-01

431

48-Pack low level waste storage facility  

SciTech Connect

ComEd has completed a design for a low level radioactive waste (LLW) storage facility, dubbed the {open_quotes}48-Pack{close_quotes}. The 48-Pack, so named because of its ability to hold 48 high integrity containers (HICs), is a modular, heavily shielded, concrete bunker. The facility was designed to serve as an effective means of augmenting the Company`s existing process waste storage capacity if and when the need arose. This paper identifies how ComEd addressed the potential need to supplement the storage capacity at its six nuclear stations through the development of the 48-Pack. Based on the criteria of meeting safety and regulatory requirements, low cost, short lead time for construction, universal design, and modularity, the 48-Pack concept was anticipated to meet and exceed the Company`s storage needs which were anticipated to end with the availability of a Central Midwest Compact (CMC) disposal facility.

Bilik, T.J. [ComEd, Downers Grove, IL (United States)

1995-11-01

432

Groundwater well with reactive filter pack  

DOEpatents

A method and apparatus for the remediation of contaminated soil and ground water wherein a reactive pack material is added to the annular fill material utilized in standard well construction techniques.

Gilmore, Tyler J. (Pasco, WA); Holdren, Jr., George R. (Kennewick, WA); Kaplan, Daniel I. (Richland, WA)

1998-01-01

433

Packing Unit Squares in a Rectangle  

Microsoft Academic Search

For a positive integer N ,l ets(N) be the side length of the minimum square into which N unit squares can be packed. This paper shows that, for given real numbers a;b 2, no more than ab (a +1 d ae) (b +1 d be) unit squares can be packed in any a0 b0 rectangle R with a0

434

NEW TEACHER WELCOME PACK: MIDDLE SCHOOL  

NSDL National Science Digital Library

Assortment of "Best Selling" books for Middle School Science Teachers. Pack includes the following books. Help! I'm Teaching Middle School Science, Exemplary Science Grades 5-8, Uncovering Student Ideas in Science, Volume 2, Doing Good Science in Middle School, Stop Faking It: Force and Motion. Books are packed into a waterproof, nylon briefcase with handle and shoulder strap. Front flap of briefcase is printed with the NSTA logo. Includes a free sample of the journal, Science Scope .

1900-01-01

435

NEW TEACHER WELCOME PACK: HIGH SCHOOL  

NSDL National Science Digital Library

Assortment of "Best Selling" books for High School Science Teachers. Pack includes the following books. Investigating Safely, Science Educator's Guide to Laboratory Assessment, How to Write to Learn Science, Science as Inquiry in the Secondary Setting, and The Biologist's Handbook. Books are packed into a waterproof, nylon briefcase with handle and shoulder strap. Front flap of briefcase is printed with the NSTA logo. Includes free sample of the journal, The Science Teacher .

1900-01-01

436

Packing numbers of rational ruled 4-manifolds  

Microsoft Academic Search

We completely solve the symplectic packing problem with equally sized balls for any rational, ruled, symplectic 4-manifolds. We give explicit formulae for the packing numbers, the generalized Gromov widths, the stability numbers, and the corresponding obstructing exceptional classes. As a corollary, we give explicit values for when an ellipsoid of type $E(a, b)$, with $\\\\frac{b}{a} \\\\in \\\\N$, embeds in a

Olguta Buse; Martin Pinsonnault

2011-01-01

437

Decontamination of pesticide packing using ionizing radiation  

NASA Astrophysics Data System (ADS)

The Brazilian agriculture activities have consumed about 288,000 tons of pesticides per year conditioned in about 107,000,000 packing with weight of approximately 23,000 tons. The discharge of empty plastic packing of pesticides can be an environmental concern causing problems to human health, animals, and plants if done without inspection and monitoring. The objective of this work is to study the ionizing radiation effect in the main pesticides used in Brazil for plastic packing decontamination. Among the commercial pesticides, chlorpyrifos has significant importance because of its wide distribution and extensive use and persistence. The radiation-induced degradation of chlorpyrifos in liquid samples and in polyethylene pack was studied by gamma radiolysis. Packing of high-density polyethylene (HDPE) three layer coextruded, named COEX, contaminated with chlorpyrifos, were irradiated using both a multipurpose Co-60 gamma irradiator and a gamma source with 5000 Ci total activity Gamma cell type. The chemical analysis of the chlorpyrifos was made using a gas chromatography associated to the Mass Spectrometry—GCMS from Shimadzu Model QP 5000. Gamma radiation was efficient for removing chlorpyrifos from the plastic packing, in all studied cases.

Duarte, C. L.; Mori, M. N.; Kodama, Yasko; Oikawa, H.; Sampa, M. H. O.

2007-11-01

438

Free volume distribution of nearly jammed hard sphere packings  

NASA Astrophysics Data System (ADS)

We calculate the free volume distributions of nearly jammed packings of monodisperse and bidisperse hard sphere configurations. These distributions differ qualitatively from those of the fluid, displaying a power law tail at large free volumes, which constitutes a distinct signature of nearly jammed configurations, persisting for moderate degrees of decompression. We reproduce and explain the observed distribution by considering the pair correlation function within the first coordination shell for jammed hard sphere configurations. We analyze features of the equation of state near jamming, and discuss the significance of observed asphericities of the free volumes to the equation of state.

Maiti, Moumita; Sastry, Srikanth

2014-07-01

439

Free volume distribution of nearly jammed hard sphere packings  

E-print Network

We calculate the free volume distributions of nearly jammed packings of monodisperse and bidisperse hard sphere configurations. These distributions differ qualitatively from those of the fluid, displaying a power law tail at large free volumes, which constitutes a distinct signature of nearly jammed configurations, persisting for moderate degrees of decompression. We reproduce and explain the observed distribution by considering the pair correlation function within the first coordination shell for jammed hard sphere configurations. We analyze features of the equation of state near jamming, and discuss the significance of observed asphericities of the free volumes to the equation of state.

Moumita Maiti; Srikanth Sastry

2014-07-25

440

Free volume distribution of nearly jammed hard sphere packings.  

PubMed

We calculate the free volume distributions of nearly jammed packings of monodisperse and bidisperse hard sphere configurations. These distributions differ qualitatively from those of the fluid, displaying a power law tail at large free volumes, which constitutes a distinct signature of nearly jammed configurations, persisting for moderate degrees of decompression. We reproduce and explain the observed distribution by considering the pair correlation function within the first coordination shell for jammed hard sphere configurations. We analyze features of the equation of state near jamming, and discuss the significance of observed asphericities of the free volumes to the equation of state. PMID:25084929

Maiti, Moumita; Sastry, Srikanth

2014-07-28

441

Compound hydraulic shear-modulated vortex amplifiers  

NASA Technical Reports Server (NTRS)

A novel two-stage shear-modulated hydraulic vortex amplifier (U.S. patent 3,520,317) has been fabricated and put through preliminary steady-state testing at the 1000 psi supply pressure level with flows up to 15 gpm. The invention comprises a conventional fluidic vortex power stage and a shear-modulated pilot stage. In the absence of any mechanical moving parts, water may be used as the hydraulic medium thus opening the way to many underseas applications. At blocked load, a control input from 0 to 150 psi was required to achieve an output from 0 to 900 psi; at wide-open load, a control input of 0 to 120 psi was needed to achieve an output from 0 to 15 gpm. The power stage has been found unsuitable for the proportional control mode because of its nonlinear performance in the intermediate load range and because of strong pressure fluctuations (plus or minus 150 psi) in the intermediate control range. The addition of the shear-modulated pilot stage improves intermediate load linearity.

Goldschmied, F. R.

1977-01-01

442

Automated hydraulic tensor for Total Knee Arthroplasty.  

PubMed

To obtain a long lifespan of knee prosthesis, it is necessary to restore the alignment of the lower limb. In some cases of severe arthrosis, the ligament envelope of the joint may be deformed, inducing an asymmetric laxity once the lower limb is realigned. Because there is not yet unanimity regarding how to optimally measure or implement soft tissue balance, we provide a means to acquire a variety of measurements. In traditional surgery, the surgeon sometimes uses a "tensor", which acts like a forceps. This system was redesigned, instrumented, actuated, and integrated into a navigation system for orthopaedic surgery. Improving the perception of the surgeon, it helps him to address the ligament balancing problem. Our first prototype has been tested on sawbones before being validated in an experiment on two cadavers. In our first attempt, the surgeon was able to assess soft tissue balance but judged the device not powerful enough, which led us to develop a new more powerful hydraulic system. In this paper, we present our approach and the first results of the new hydraulic tensor which is currently in an integration process. PMID:17518405

Marmignon, C; Leimnei, A; Lavallée, S; Cinquin, P

2005-12-01

443

Measuring Hydraulic Properties of Soil-Foundry Sand Mixtures  

NASA Astrophysics Data System (ADS)

The foundry industry produces clay coated sand particles that have potential to affect soil water retention and conductivity if mixed with soils at the proper ratio. The purpose of our study was to determine the effects of mixing foundry sand on increasing the saturated hydraulic conductivity of slowly permeable soils. Our methods included mixing Walla-Walla silt loam soil with increasing volumes of foundry sand from 0% to 100%. We then used several packing methods to determine the optimum bulk density for our automated retention and outflow experiments. To increase the range of the retention function, we also measured soil water retention using pressure plates at pressures between 1000 and 15000 cm pressure head. We measured saturated hydraulic conductivity using the constant head method and a single blind approach (the Ksat was measured in two labs, one had knowledge of the mixtures and one had no knowledge of the mixtures). The single blind approach was used to reduce the chance of bias in measuring Ksat and water retention. Our results for the saturated hydraulic conductivity did indicate that additions of foundry sand had a limited effect on Ksat until a critical level of sand was added to the mixture. The retention function was similarly affected by increasing volumes of foundry sand. The rankings of the Ksat measurements between the labs was constant, but the values obtained did differ (some significantly). For the Walla-Walla soil, additions of foundry sands exceeding 40% were needed to affect the measured Ksat and retention function. At these large volumes of foundry sands, it may be more appropriate to use the sands for new installations of turf grass such as athletic fields, and/or golf greens. We are continuing to study the characteristics of different foundry sands and quantifying their effects on the hydraulic properties of clay soils.

Shouse, P. J.; Dungan, R. S.; Dees, N.; Fargerlund, J.

2005-12-01

444

Control apparatus for hydraulically driven generator  

SciTech Connect

Apparatus for controlling a hydraulically driven generator for supplying electrical power to power mains. The generator is coupled to a turbine driven by a fluid flow through a duct. The duct has a one-fourth turn butterfly valve controlled by a fluid-actuated operator and the operator receives fluid from the duct by way of a normally closed valve which, when energized, creates water pressure on the operator for opening the butterfly valve. A second, normally open solenoid provides an emergency exit for the water from the operator to relieve the water pressure thereon and thereby close the butterfly valve when certain conditions exist, such as sudden loss of line voltage, overvoltage or deviation in frequency of the line voltage. A differential pressure switch across the turbine rotor also controls the starting of the system to assure proper flow of fluid through the duct before commencing operation of the generator itself.

Beckwith, S.

1985-08-06

445

THE JOLT-PACK FABRICATION OF SPECIAL CERAMIC WARE  

Microsoft Academic Search

The jolt-pack method for fabrication of refractory crucibles and other ; shapes is described. The particle size distribution of the material to be packed ; was found to be an important consideratibn in this method. Data are presented on ; packing densities of various graded fractions of beryllia and the development of ; a dense-packing mixture is described. (auth);

F. W. Calderwood; D. R. Wilder; H. A. Wilheim

1961-01-01

446

A genetic algorithm for packing in three dimensions  

Microsoft Academic Search

Recent research in Bin Packing haa almost exclusively been in two dimensions. In this paper we extend the classic Bin Packing problem to three dimensions. We investigate the solutions for the three dmenaicmal packing problem using fust fit ond next fit packing strategies with and without genetic algorithms. Five data sets were used to test our algorithms, both random and

Arthur L. Corcoran III; Roger L. Wainwright

1992-01-01

447

Determining the Molecular Packing Arrangements on Protein Crystal Faces by Atomic Force Microscopy  

NASA Technical Reports Server (NTRS)

Periodic Bond Chain (PBC) analysis of the packing of tetragonal lysozyme crystals have revealed that there are two possible molecular packing arrangements for the crystal faces. The analysis also predicted that only one of these, involving the formation of helices about the 4(sub 3) axes, would prevail during crystal growth. In this study high resolution atomic force microscopy (AFM) was employed to verify these predictions for the (110) crystal face. A computer program was developed which constructs the expected AFM image for a given tip shape for each possible molecular packing arrangement. By comparing the actual AFM image with the predicted images the correct packing arrangement was determined. The prediction of an arrangement involving 4(sub 3) helices was confirmed in this manner,"while the alternate arrangement was not observed. The investigation also showed the protein molecules were packed slightly closer about the 4(sub 3) axes than in the crystallographic arrangement of the crystal interior. This study demonstrates a new approach for determining the molecular packing arrangements on protein crystal faces. It also shows the power of combining a theoretical PBC analysis with experimental high resolution AFM techniques in probing protein crystal growth processes at the molecular level.

Li, Huayu; Perozzo, Mary A.; Konnert, John H.; Nadarajan, Arunan; Pusey, Marc L.

1998-01-01

448

Application study of magnetic fluid seal in hydraulic turbine  

NASA Astrophysics Data System (ADS)

The waterpower resources of our country are abundant, and the hydroelectric power is developed, but at present the main shaft sealing device of hydraulic turbine is easy to wear and tear and the leakage is great. The magnetic fluid seal has the advantages of no contact, no wear, self-healing, long life and so on. In this paper, the magnetic fluid seal would be used in the main shaft of hydraulic turbine, the sealing structure was built the model, meshed the geometry, applied loads and solved by using MULTIPHYSICS in ANSYS software, the influence of the various sealing structural parameters such as tooth width, height, slot width, sealing gap on the sealing property were analyzed, the magnetic fluid sealing device suitable for large-diameter shaft and sealing water was designed, the sealing problem of the hydraulic turbine main shaft was solved effectively which will bring huge economic benefits.

Yu, Z. Y.; Zhang, W.

2012-11-01

449

Dense periodic packings of tetrahedra with small repeating units  

E-print Network

We present a one-parameter family of periodic packings of regular tetrahedra, with the packing fraction $100/117\\approx0.8547$, that are simple in the sense that they are transitive and their repeating units involve only four tetrahedra. The construction of the packings was inspired from results of a numerical search that yielded a similar packing. We present an analytic construction of the packings and a description of their properties. We also present a transitive packing with a repeating unit of two tetrahedra and a packing fraction $\\frac{139+40\\sqrt{10}}{369}\\approx0.7194$.

Yoav Kallus; Veit Elser; Simon Gravel

2010-03-19

450

Galactic hydraulic drop?  

E-print Network

Galaxies and galaxy clusters are observed to have a rather non-trivial radial behaviour. The observations show that the radial profiles change from one power-law profile near the centre to another power-law profile in the outer region. We present a simple explanation for this complex behaviour by finding the analytical solutions to the governing hydrodynamic equations. We see that the origin of this complexity is the collisional nature of the baryonic plasma, possibly related to a turbulence-enhanced viscosity.

Steen H. Hansen

2003-10-10

451

Modeling biooxidation of iron in packed-bed reactor  

SciTech Connect

Acid mine drainage (AMD) from active and abandoned mines continues to be an important source of water pollution in the US and around the world. AMD typically has high levels of acidity, sulfate, and metals. A model based on Monod kinetics and originally developed for use with rotating biological contactors was modified for use with a packed-bed column reactor. The reactor was filled with expanded polystyrene beads to immobilize chemolithotrophic bacteria and fed up to 570 mg L{sup {minus}1} ferrous iron [Fe(II)] in simulated acid mine drainage. A tracer study indicated changing behavior as a function of hydraulic residence time (HRT), with a transition from complete mix flow behavior to plug flow behavior as HRT decreased. The Fe(II) oxidation efficiency exceeded 95% until the HRT was reduced below 0.5 h. The reactor performance could be predicted with the model using estimates from the literature for {cflx u} and Y. The experimentally determined half-saturation constant K{sub s} was found to range from 5 to 12 mg L{sup {minus}1}. The maximum volumetric capacity constant R{sub max} was estimated to be {approximately}360 mg Fe(II)h{sup {minus}1} L{sup {minus}1} beads under complete mix flow conditions but appeared to be as high as 724 mg Fe(II)h{sup {minus}1} L{sup {minus}1} beads as conditions approached plug flow at short HRTs.

Diz, H.R. [Gannon Univ., Erie, PA (United States). Dept. of Environmental Science and Engineering] [Gannon Univ., Erie, PA (United States). Dept. of Environmental Science and Engineering; Novak, J.T. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)] [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)

1999-02-01

452

Application of new packing material in endoscopic nasal surgery  

PubMed Central

Objective: To show the efficacy and comfort of pneumatic bag packing after the endoscopic nasal surgery. Pneumatic bag packing may be recommendable in terms of comfort and efficacy after endoscopic nasal surgery. Significant findings: There were statistical significant differences between the pneumatic bag packing and the expansive sponge packing regarding subjective symptoms and objective findings after surgery. Conclusions: Pneumatic bag packing may be recommendable in terms of comfort and efficacy after endoscopic nasal surgery. PMID:25785173

Yin, Haiying; Han, Fei; Cui, Zhaoyang

2015-01-01

453

7 CFR 3201.28 - Stationary equipment hydraulic fluids.  

Code of Federal Regulations, 2014 CFR

...false Stationary equipment hydraulic fluids. 3201.28 Section...28 Stationary equipment hydraulic fluids. (a) Definition...formulated for use in stationary hydraulic equipment systems that have various...

2014-01-01

454

7 CFR 3201.28 - Stationary equipment hydraulic fluids.  

Code of Federal Regulations, 2012 CFR

...false Stationary equipment hydraulic fluids. 3201.28 Section...28 Stationary equipment hydraulic fluids. (a) Definition...formulated for use in stationary hydraulic equipment systems that have various...

2012-01-01

455

7 CFR 3201.28 - Stationary equipment hydraulic fluids.  

Code of Federal Regulations, 2013 CFR

...false Stationary equipment hydraulic fluids. 3201.28 Section...28 Stationary equipment hydraulic fluids. (a) Definition...formulated for use in stationary hydraulic equipment systems that have various...

2013-01-01

456

7 CFR 2902.28 - Stationary equipment hydraulic fluids.  

Code of Federal Regulations, 2011 CFR

...false Stationary equipment hydraulic fluids. 2902.28 Section...28 Stationary equipment hydraulic fluids. (a) Definition...formulated for use in stationary hydraulic equipment systems that have various...

2011-01-01

457

77 FR 55770 - Airworthiness Directives; Cessna Aircraft Company Airplanes  

Federal Register 2010, 2011, 2012, 2013, 2014

...from the area of the landing gear's hydraulic power pack system. This proposed AD would require you inspect the aircraft's hydraulic power pack wiring for incorrect installation...from the area of the landing gear's hydraulic power pack system and resulted in a...

2012-09-11

458

Effects of Nasopore Packing on Dacryocystorhinostomy  

PubMed Central

Purpose To investigate the effects of placement of the absorbable packing material Nasopore at the anastomosis site of newly formed mucosal flaps on postoperative re-bleeding, discomfort, and on the success rate of dacryocystorhinostomy (DCR). Methods A review of the medical records of patients with primary acquired nasolacrimal duct obstruction that underwent external or endonasal DCR by a single surgeon was performed. The degree of re-bleeding, discomfort, and postoperative results, including anatomical success, functional success and postoperative nasal findings such as granulation, synechiae, and membrane formation were compared in patients whose anastomosis site was packed with either Nasopore or Merocel, a non-absorbable packing material. Results A total of 77 patients (101 eyes) were included. Of the 101 eyes, 30 were packed with Nasopore, while 71 were packed with Merocel. The Nasopore group showed significantly better results than the Merocel group in the degree of re-bleeding and the level of patient discomfort (p = 0.000, 0.039, respectively; Pearson's chi-square test), whereas there were no statistically significant differences between the two groups in postoperative anatomical and functional success (p > 0.05). Conclusions Nasopore significantly reduced postoperative nasal re-bleeding and patient discomfort during the early post-surgical period, but failed to show an effect on the postoperative anatomical and functional success of DCR. PMID:23543801

Jang, Sun Young; Lee, Kyou Ho; Lee, Sang Yeul

2013-01-01

459

Soft particle packings near jamming: correlations in static structure  

NASA Astrophysics Data System (ADS)

We extend our previous results report on 2D simulations of soft harmonic packings at various area fractions above the jamming point c. We employ several statistical analyses to determine whether one or more characteristic lengths can be associated with either the quenched stress field in the packing or the structure of local elastic moduli. First, we define a locally anisotropic variant of the standard two-point correlation function. This anisotropic correlation function follows a power law even in globally isotropic stress states with a independent exponent and no discernible cutoff within the statistically accessible regime. Secondly, we define a coarse-grained stress field on a scale R. The average anisotropic component and the fluctuations in the trace can both be collapsed onto similar master curves after rescaling R by a characteristic length scale ?. ? accelerates as approaches c, consistent with a divergence at c. Surprisingly, a similar analysis on the local coarse-grained elastic modulus tensor shows a non-trivial power-law scaling behavior as a function of the coarse-graining size yet no characteristic ? as exhibited by the stress.

Karimi, Kamran; Maloney, Craig

2013-03-01

460

Method for directional hydraulic fracturing  

DOEpatents

A method for directional hydraulic fracturing using borehole seals to confine pressurized fluid in planar permeable regions, comprising: placing a sealant in the hole of a structure selected from geologic or cemented formations to fill the space between a permeable planar component and the geologic or cemented formation in the vicinity of the permeable planar component; making a hydraulic connection between the permeable planar component and a pump; permitting the sealant to cure and thereby provide both mechanical and hydraulic confinement to the permeable planar component; and pumping a fluid from the pump into the permeable planar component to internally pressurize the permeable planar component to initiate a fracture in the formation, the fracture being disposed in the same orientation as the permeable planar component.

Swanson, David E. (West St. Paul, MN); Daly, Daniel W. (Crystal, MN)

1994-01-01

461

Electrokinetic high pressure hydraulic system  

DOEpatents

An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based systems. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (Microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

Paul, Phillip H. (Livermore, CA); Rakestraw, David J. (Fremont, CA); Arnold, Don W. (Livermore, CA); Hencken, Kenneth R. (Pleasanton, CA); Schoeniger, Joseph S. (Oakland, CA); Neyer, David W. (Castro Valley, CA)

2001-01-01

462

Electrokinetic high pressure hydraulic system  

DOEpatents

An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based system. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

Paul, Phillip H.; Rakestraw, David J.; Arnold, Don W.; Hencken, Kenneth R.; Schoeniger, Joseph S.; Neyer, David W.

2003-06-03

463

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.  

Code of Federal Regulations, 2011 CFR

...supplies energy, in the event of a primary brake power source failure. Brake power assist unit means a device installed in a hydraulic...muscular force on the service brake control. Brake power unit means a device installed in a brake...

2011-10-01

464

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.  

Code of Federal Regulations, 2014 CFR

...supplies energy, in the event of a primary brake power source failure. Brake power assist unit means a device installed in a hydraulic...muscular force on the service brake control. Brake power unit means a device installed in a brake...

2014-10-01

465

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.  

Code of Federal Regulations, 2012 CFR

...supplies energy, in the event of a primary brake power source failure. Brake power assist unit means a device installed in a hydraulic...muscular force on the service brake control. Brake power unit means a device installed in a brake...

2012-10-01

466

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.  

Code of Federal Regulations, 2010 CFR

...supplies energy, in the event of a primary brake power source failure. Brake power assist unit means a device installed in a hydraulic...muscular force on the service brake control. Brake power unit means a device installed in a brake...

2010-10-01

467

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.  

Code of Federal Regulations, 2013 CFR

...supplies energy, in the event of a primary brake power source failure. Brake power assist unit means a device installed in a hydraulic...muscular force on the service brake control. Brake power unit means a device installed in a brake...

2013-10-01

468

Robust Force Control of a 6-Link Electro-Hydraulic Manipulator  

NASA Astrophysics Data System (ADS)

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. This maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulator because hydraulic manipulators have the advantage of electric insulation and power/mass density. Meanwhile an electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous assembly tasks using hydraulic manipulators. In this paper, the robust force control of a 6-link electro-hydraulic manipulator system used in the real maintenance task of active electic line is examined in detail. A nominal model for the system is obtained from experimental frequency responses of the system, and the deviation of the manipulator system from the nominal model is derived by a multiplicative uncertainty. Robust disturbance observers for force control are designed using this information in an H? framework, and implemented on the two different setups. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved even if the stiffness of environment and the shape of wall change.

Ahn, Kyoungkwan; Yokota, Shinichi

469

Advantages of Oscillatory Hydraulic Tomography  

NASA Astrophysics Data System (ADS)

Characterizing the subsurface is significant for most hydrogeologic studies, such as those involving site remediation and groundwater resource explo¬ration. A variety of hydraulic and geophysical methods have been developed to estimate hydraulic conductivity and specific storage. Hydraulic methods based on the analysis of conventional pumping tests allow the estimation of conductivity and storage without need for approximate petrophysical relations, which is an advantage over most geophysical methods that first estimate other properties and then infer values of hydraulic parameters. However, hydraulic methods have the disadvantage that the head-change signal decays with distance from the pumping well and thus becomes difficult to separate from noise except in close proximity to the source. Oscillatory hydraulic tomography (OHT) is an emerging technology to im¬age the subsurface. This method utilizes the idea of imposing sinusoidally varying pressure or discharge signals at several points, collecting head observations at several other points, and then processing these data in a tomographic fashion to estimate conductivity and storage coefficients. After an overview of the methodology, including a description of the most important potential advantages and challenges associated with this approach, two key promising features of the approach will be discussed. First, the signal at an observation point is orthogonal to and thus can be separated from nuisance inputs like head fluctuation from production wells, evapotranspiration, irrigation, and changes in the level of adjacent streams. Second, although the signal amplitude may be weak, one can extract the phase and amplitude of the os¬cillatory signal by collecting measurements over a longer time, thus compensating for the effect of large distance through longer sampling period.

Kitanidis, P. K.; Bakhos, T.; Cardiff, M. A.; Barrash, W.

2012-12-01

470

Electokinetic high pressure hydraulic system  

DOEpatents

A compact high pressure hydraulic system having no moving parts for converting electric potential to hydraulic force and for manipulating fluids. Electro-osmotic flow is used to provide a valve and means to compress a fluid or gas in a capillary-based system. By electro-osmotically moving an electrolyte between a first position opening communication between a fluid inlet and outlet and a second position closing communication between the fluid inlet and outlet the system can be configured as a valve. The system can also be used to generate forces as large as 2500 psi that can be used to compress a fluid, either a liquid or a gas.

Paul, Phillip H. (Livermore, CA); Rakestraw, David J. (Fremont, CA)

2000-01-01

471

Hydraulic jumps on an incline  

E-print Network

When a fluid jet strikes an inclined solid surface at normal incidence, gravity creates a flow pattern with a thick outer rim resembling a parabola and reminiscent of a hydraulic jump. There appears to be little theory or experiments describing simple aspects of this phenomenon, such as the maximum rise height of the fluid above the impact point, and its dependence on jet velocity and inclination angle. We address this with experiments, and present a simple theory based on horizontal hydraulic jumps which accounts for the rise height and its scaling, though without describing the shape of the parabolic envelope.

Jean-Luc Thiffeault; Andrew Belmonte

2010-09-01

472

Poroelasticity in hydraulic fracturing simulators  

SciTech Connect

This paper describes a 2D hydraulic fracturing simulator that relies on Biot's theory of poroelasticity. The simulator is based on a poroelastic extension of the displacement-discontinuity (DD) method: it uses time and space distributions of impulse-point DD's and impulse-point sources. Because both solutions satisfy Biot's equations, the model fully accounts for the coupling between fluid diffusion and rock deformation. Thus, this model yields a rigorous determination of the influences of fluid leakoff on fracture width and of opening distribution on reservoir pore pressures. Some preliminary results relevant to hydraulic fracturing are presented.

Vandamme, L. (Noranda Technology Centre, Pte. Claire, Quebec (CA)); Roegiers, J.C. (School of Petroleum and Geological Engineering, Univ. of Oklahoma, OK (US))

1990-09-01

473

Method for packed column separations and purifications  

DOEpatents

The invention encompasses a method of packing and unpacking a column chamber. A mixture of a fluid and a matrix material are introduced through a column chamber inlet so that the matrix material is packed within a column chamber to form a packed column. The column chamber having the column chamber inlet or first port for receiving the mixture further has an outlet port and an actuator port. The outlet port is partially closed for capturing the matrix material and permitting the fluid to flow therepast by rotating relative one to the other of a rod placed in the actuator port. Further rotation relative one to the other of the rod and the column chamber opens the outlet and permits the matrix material and the fluid to flow therethrough thereby unpacking the matrix material from the column chamber.

Holman, David A. (Richland, WA); Bruckner-Lea, Cynthia J. (Richland, WA); Brockman, Fred J. (Kennewick, WA); Chandler, Darrell P. (Richland, WA)

2006-08-15

474

Mechanical Behavior of Randomly Packed Nanoellipsoid Films  

NASA Astrophysics Data System (ADS)

We investigate the mechanical behavior of films composed of randomly packed nanoellipsoids with varying aspect ratio using nanoindentation. The packing fraction of nanoellispoids, determined using gravimetric analysis, is found to have excellent agreement with previously reported results based on simulations. Our study shows that the volume fraction of the films rather than the aspect ratio of the particles is the primary factor that determines the modulus and hardness of nanoellipsoid films. We show, however, that the aspect ratio of the nanoellipsoids has a significant impact on the toughness and the failure mechanism of nanoellipsoid films. While short aspect ratio nanoellipsoid films develop shear bands under nanoindentation, films with high aspect ratio nanoellipsoids do not exhibit shear band formation. We will discuss the potential relevance of our results to other types of random packings such as granular materials and bulk metallic glasses.

Lee, Daeyeon; Zhang, Lei; Feng, Gang

2013-03-01

475

Spontaneous Crystallization in Athermal Polymer Packings  

PubMed Central

We review recent results from extensive simulations of the crystallization of athermal polymer packings. It is shown that above a certain packing density, and for sufficiently long simulations, all random assemblies of freely-jointed chains of tangent hard spheres of uniform size show a spontaneous transition into a crystalline phase. These polymer crystals adopt predominantly random hexagonal close packed morphologies. An analysis of the local environment around monomers based on the shape and size of the Voronoi polyhedra clearly shows that Voronoi cells become more spherical and more symmetric as the system transits to the ordered state. The change in the local environment leads to an increase in the monomer translational contribution to the entropy of the system, which acts as the driving force for the phase transition. A comparison of the crystallization of hard-sphere polymers and monomers highlights similarities and differences resulting from the constraints imposed by chain connectivity. PMID:23263666

Karayiannis, Nikos Ch.; Foteinopoulou, Katerina; Laso, Manuel

2013-01-01

476

Climbing robot actuated by meso-hydraulic artificial muscles  

NASA Astrophysics Data System (ADS)

This paper presents the design, construction, experimental characterization, and system testing of a legged, wall-climbing robot actuated by meso-scale hydraulic artificial muscles. While small wall-climbing robots have seen increased research attention in recent years, most authors have primarily focused on designs for the gripping and adhesion of the robot to the wall, while using only standard DC servo-motors for actuation. This project seeks to explore and demonstrate a different actuation mechanism that utilizes hydraulic artificial muscles. A four-limb climbing robot platform that includes a full closed-loop hydraulic power and control system, custom hydraulic artificial muscles for actuation, an on-board microcontroller and RF receiver for control, and compliant claws with integrated sensing for gripping a variety of wall surfaces has been constructed and is currently being tested to investigate this actuation method. On-board power consumption data-logging during climbing operation, analysis of the robot kinematics and climbing behavior, and artificial muscle force-displacement characterization are presented to investigate and this actuation method.

Bryant, Matthew; Fitzgerald, Jason; Miller, Samuel; Saltzman, Jonah; Kim, Sangkyu; Lin, Yong; Garcia, Ephrahim

2014-03-01

477

Hydraulic geometry of river cross sections; theory of minimum variance  

USGS Publications Warehouse

This study deals with the rates at which mean velocity, mean depth, and water-surface width increase with water discharge at a cross section on an alluvial stream. Such relations often follow power laws, the exponents in which are called hydraulic exponents. The Langbein (1964) minimum-variance theory is examined in regard to its validity and its ability to predict observed hydraulic exponents. The variables used with the theory were velocity, depth, width, bed shear stress, friction factor, slope (energy gradient), and stream power. Slope is often constant, in which case only velocity, depth, width, shear and friction factor need be considered. The theory was tested against a wide range of field data from various geographic areas of the United States. The original theory was intended to produce only the average hydraulic exponents for a group of cross sections in a similar type of geologic or hydraulic environment. The theory does predict these average exponents with a reasonable degree of accuracy. An attempt to forecast the exponents at any selected cross section was moderately successful. Empirical equations are more accurate than the minimum variance, Gauckler-Manning, or Chezy methods. Predictions of the exponent of width are most reliable, the exponent of depth fair, and the exponent of mean velocity poor. (Woodard-USGS)

Williams, Garnett P.

1978-01-01

478

Abdominal packing for surgically uncontrollable hemorrhage.  

PubMed Central

Planned intra-abdominal packing for surgically uncontrollable hemorrhage from liver and retroperitoneal injuries exacerbated by hypothermia, acidosis, and coagulopathy regained popularity over the past decade. The authors reviewed 39 patients injured between August 1985 and September 1990; 31 packed for liver injuries, eight for nonliver injuries. The overall mortality rate was 44% (17/39); 9 (23%) exsanguinated, 3 (8%) died of head injuries, 3 (8%) of multisystem organ failure, 2 (5%) of late complications. The mean age was 33.9 +/- 16.2 (range, 16 to 79); there were 26 men and 13 women. Relaparotomy for pack removal was performed 2.0 +/- 1.1 days (range, 1 to 7) after initial operation. The authors identified intraoperative risk factors of pH less than or equal to 7.18, temperature less than or equal to 33 C, prothrombin time greater than or equal to 16, partial thromboplastin time greater than or equal to 50, and transfusion of 10 units or more of blood as highly predictive of outcome. Patients with four to five risk factors (n = 3) had a 100% mortality rate (p less than 0.04); two to three risk factors (n = 12), 83% mortality rate (p less than 0.003), compared with zero to one risk factors (n = 24), 18% mortality rate. Complications developed in six of 22 survivors (27%): 5 abdominal abscesses (23%), 2 wound dehiscences (9%), and 2 enterocutaneous fistulae (9%). Intra-abdominal packing will not stop all bleeding; 23% of the patients exsanguinated. In 77%, packing helped achieve hemostasis we believed was not otherwise possible. Packing may be done to prevent the development of acidosis, hypothermia, and coagulopathy or may be done early in the treatment of cold, acidotic patients rather than massive transfusion in the face of surgically uncorrectable bleeding. PMID:1616383

Sharp, K W; Locicero, R J

1992-01-01

479

Assessing plant hydraulic architecture with ultrasonic acoustic emission techniques  

NASA Astrophysics Data System (ADS)

Water is transported through the xylem of plants under tension (negative pressure). If the tension within a xylem conduit exceeds a critical value, cavitation can occur, which if followed by embolism leads to blockage of water transport through the conduit. Plant species and different organs within the plant such as roots, stems and leaves vary widely in the xylem tension thresholds at which cavitation events begin to occur. Massive cavitation and embolism can lead to catastrophic hydraulic failure and plant death from dehydration. Ultrasonic acoustic emission (UAE) transducers provide a non-invasive means of detecting cavitation events in plants and recording the accumulation of these events through time. When used in combination with other techniques, recording of UAEs can be a powerful tool for characterizing and understanding plant hydraulic architecture; the collection of properties that determine the efficiency and vulnerability of water transport from roots to leaves. The hydraulic architecture of leaves is particularly complex because water must traverse the dead cells of the xylem plus an extra-xylary pathway consisting of living cells and intercellular spaces before it arrives at the internal evaporating surfaces. We used UAE, imaging and other techniques to determine the extent to which dehydration-induced declines in leaf hydraulic conductance were associated with xylem cavitation and embolism versus changes in the conductance of the extra-xylary pathway. In most of the evergreen and deciduous tree species studied there was a close correspondence between the trajectories of cumulative UAEs and loss of whole-leaf hydraulic conductance during dehydration. The mean amplitude of UAEs was positively correlated with mean conduit diameter indicating that in addition to detecting cavitation events, analysis of UAE features can provide information about relative changes in xylem hydraulic conductivity because conductivity is a function of conduit radius to the fourth power. We were unable to detect UAEs from conduits smaller than about 4 micrometers in diameter. The occurrence of embolism in leaf xylem was confirmed independently with cryo-SEM and light microscopy imaging. As expected, there was considerable variation among species in the leaf water potential thresholds at which xylem cavitation and loss of hydraulic conductance began to occur. Contrary to suggestions from some published studies, we saw no evidence of reversible partial xylem conduit collapse instead of cavitation during dehydration. Results from our field studies indicate that dehydration-induced embolism in leaf xylem is completely reversible over a 24-hour cycle, but the mechanism for refilling xylem conduits is unknown. We discuss constraints on the application of UAE techniques for studying plant hydraulics.

Meinzer, F. C.; Johnson, D.; McCulloh, K.; Woodruff, D.

2012-12-01

480

Plankton filtration with compressible crumb rubber packs.  

PubMed

The experiments described provide insight into the feasibility of using compressible particulate packs to filter live plankton. The pore constriction sizes are controlled by subjecting the filter pack to isotropic confinement, thereby allowing for: (1) enhanced filtration upon confinement and (2) enhanced unclogging upon relaxation. Results show that filtration efficiency increases with increasing confinement; however, complete plankton retention is difficult to attain due to the plankton's ability to pass through pore constrictions that are smaller than the plankton size. The results are anticipated to offer potential benefits to ballast treatment and aquatic filtration operations. PMID:21126750

Karanikola, Vasiliki; Ngo, Anh T; Valdes, Julio R

2011-01-01

481

46 CFR 28.880 - Hydraulic equipment.  

Code of Federal Regulations, 2010 CFR

...880 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.880 Hydraulic equipment. (a) Each hydraulic system...

2010-10-01

482

Removing freon gas from hydraulic fluid  

NASA Technical Reports Server (NTRS)

Dissolved freon gas is removed from hydraulic fluid by raising temperature to 150 F and bubbling dry nitrogen gas through it, even while fluid circulates through hydraulic system. Procedure reduces parts corrosion, sludge formation, and contamination.

Williams, B. B.; Mitchell, S. M.; State, T. S.

1981-01-01

483

CRITICALITY CURVES FOR PLUTONIUM HYDRAULIC FLUID MIXTURES  

SciTech Connect

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.

WITTEKIND WD

2007-10-03

484

Ensemble smoother assimilation of hydraulic head and return flow data to estimate hydraulic conductivity distribution  

E-print Network

and return flow data to estimate hydraulic conductivity distribution, Water Resour. Res., 46, W12543, doi:10Ensemble smoother assimilation of hydraulic head and return flow data to estimate hydraulic and data measurements, an ensemble smoother (ES) to provide enhanced estimates of aquifer hydraulic

Bau, Domenico A.

485

Hydraulic conductivity imaging from 3-D transient hydraulic tomography at several pumping/observation densities  

E-print Network

Hydraulic conductivity imaging from 3-D transient hydraulic tomography at several pumping August 2013; accepted 7 September 2013; published 13 November 2013. [1] 3-D Hydraulic tomography (3-D HT (primarily hydraulic conductivity, K) is estimated by joint inversion of head change data from multiple

Barrash, Warren

486

Hydraulic Properties of Unsaturated Soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

Many agrophysical applications require knowledge of the hydraulic properties of unsaturated soils. These properties reflect the ability of a soil to retain or transmit water and its dissolved constituents. The objective of this work was to develop an entry for the Encyclopedia of Agrophysics that w...

487

Introduction to Hydraulics. Student's Manual.  

ERIC Educational Resources Information Center

This manual on hydraulics is one of a series of individualized instructional materials for students. The manual is self-paced, but is designed to be used under the supervision of an instructor. The manual contains 10 assignments, each with all the information needed, a list of objectives that should be met, and exercise questions that can help in…

Texas Univ., Austin. Extension Instruction and Materials Center.

488

Introduction to Hydraulics. Instructor's Guide.  

ERIC Educational Resources Information Center

This instructor's guide on hydraulics is part of a series of individualized instructional materials. The guide is provided to help the instructor make certain that each student gets the most benefit possible from both the student's manual and what he/she does on the job. Notes for the instructor contain suggestions on how the student should use…

Texas Univ., Austin. Extension Instruction and Materials Center.

489

Thermal-Hydraulic-Analysis Program  

NASA Technical Reports Server (NTRS)

ELM computer program is simple computational tool for modeling steady-state thermal hydraulics of flows of propellants through fuel-element-coolant channels in nuclear thermal rockets. Evaluates various heat-transfer-coefficient and friction-factor correlations available for turbulent pipe flow with addition of heat. Comparisons possible within one program. Machine-independent program written in FORTRAN 77.

Walton, J. T.

1993-01-01

490

Flow Distribution in Hydraulic Systems  

NASA Technical Reports Server (NTRS)

General Flow Distribution Program analyzes pressure drops and flow distribution in closed and open hydraulic systems. Analyzes system on basis of incompressible flow though system may contain either compressible or incompressible fluid. Program solves fixed or variable flow problems for series, parallel, or series/parallel systems.

Nguyen, S. N.

1983-01-01

491

Hydro Hydraulics - a disappearing art?  

Microsoft Academic Search

Over the past decade, there have been several instances where the performance of new hydro developments has been compromised by unsatisfactory operation of some component associated with the hydraulic design of the facility. This paper will outline the types of deficiencies encountered, and suggest some remedies. The incidents include - gravel entrainment at intakes; \\

J. L. Gordon

2007-01-01

492

Passing Fish Through Hydraulic Turbines  

Microsoft Academic Search

Beginning in 1959, the Walla Walla District, U. S. Army Corps of Engineers, under auspices of the Corps of Engineers' Fisheries Engineering Research Program, has conducted extensive tests on downstream passage of fish through hydraulic turbines, utilizing both model and prototype installations. Purposes of the tests were (1) to establish design criteria for high-head Francis-type turbines that will provide optimum

Frederick K. Cramer; Raymond C. Oligher

1964-01-01

493

Manual or hydraulic gearshifting apparatus  

SciTech Connect

A vehicle transmission control apparatus is described which consists of: a plurality of shift members for operating a vehicle transmission; a lever adapted for linear movement into a plurality of positions, one each of the lever being operatively coupled to a different one of the shift members in each of the positions; the lever being further adapted for pivotal movement in response to which the one end of the lever actuates the operatively coupled shift member; a select actuator means comprising a select hydraulic cylinder and a select piston retained thereby, the select piston being coupled to the lever and hydraulically controlled to produce the linear movement thereof; a shift actuator means comprising a shift hydraulic cylinder and a shift piston retained thereby, the shift piston being coupled to the lever and hydraulically controlled to produce the pivotal movement thereof; a casing means retaining the lever, the select actuator means, and the shift actuator means; and a control member comprising a portion within the casing means and coupled to the lever and a manually accessible portion always disposed outside the casing means and having means adapted for manual actuation to produce either the linear or the pivotal movement of the lever.

Ishida, H.; Kojima, Y.

1986-04-08

494

Tree Hydraulics: How Sap Rises  

ERIC Educational Resources Information Center

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…

Denny, Mark

2012-01-01

495

Hydraulic fracturing with a refractory proppant for sand control  

SciTech Connect

A sand control and heat transfer method is described for use in a borehole having an unconsolidated or loosely consolidated oil or gas reservoir which is otherwise likely to introduce substantial amounts of sand into the borehole, comprising: (a) providing a borehole casing through the reservoir; (b) perforating the casing at preselected intervals therealong to form at least one of longitudinal, in-line perforations; (c) hydraulically fracturing the reservoir by injecting a fracturing fluid containing a fine grain fused refractory material which comprises substantially silicon carbide or silicon nitride, and a clay stabilizing agent; (d) injecting a proppant comprising a gravel packing fused refractory material comprised substantially of silicon carbide or silicon nitride into the fracture, whereby a first layer of fine grain fused refractory material is held in place along the entire face of the fracture by a second layer of gravel packing fused refractory material also extending along the entire length of the fracture thereby excluding fines; and (e) producing oil or gas from the reservoir through the fracture into the borehole casing via a thermal oil recovery method which proppant and layers provide for increased heat transfer into the formation.

Jennings, A.R. Jr.; Stowe, L.R.

1989-04-04

496

Computer-monitored hydraulic bulging of tubes  

Microsoft Academic Search

A hydraulic bulging machine with independent pressure and axial-force control has been designed and constructed. This machine consists of a horizontal press frame with two opposed hydraulic units at the ends of two sliding units carrying the die halves. Two sets of three hydraulic cylinders open and close the die halves containing the tube to be bulged. Once the die

S. Thiruvarudchelvan; G. L. Seet; H. E. Ang

1996-01-01

497

Hydraulic actuator motion limiter ensures operator safety  

NASA Technical Reports Server (NTRS)

Device regulates action of hydraulic linkage to control column to minimize hazard to operator. Primary components of device are flow rate control valve, limiter accumulator, and shutoff valve. Limiter may be incorporated into other hydraulic systems to prevent undue wear on hydraulic actuators and associated components.

Steinmetz, C. P.

1971-01-01

498

Nonlinear Control of a Hydraulic Parallel Manipulator  

Microsoft Academic Search

An adaptive nonlinear controller is proposed for position tracking in hydraulic robots by adopting the backstepping methodology. Full system models including rigid body and hydraulic dynamics are incorporated in the design. The tracking errors are shown to be asymptotically stable in the presence of parametric uncertainties using Lyapunov analysis. The controller is applied to a Stewart type hydraulic manipulator. Simulation

Mohammad Reza Sirouspour; S. E. Salcudean

2001-01-01

499

Original article Root and shoot hydraulic conductance  

E-print Network

@univ.trieste.it A low hydraulic conductance in xylem is expected to cause a low leaf water potential, because leaf waterOriginal article Root and shoot hydraulic conductance of seven Quercus species Andrea Nardini) and shoot (KS) hydraulic conductances of seven different Quercus species, as well as the leaf blade

Paris-Sud XI, Université de

500

Design and Technology for Hydraulic Clay Fills  

Microsoft Academic Search

Hydraulic fills (HFs), in accordance with a classification of hydraulic structures, have been assigned to a class of temporary long-term collectors of industrial wastes which operate under the conditions of excess hydrostatic pressure that usually come from imperfections of the dredging technology orand improper operation of the water discharge system. By design, a hydraulic fill, in distinction from a storage

V. I. Kaminskaya

2004-01-01