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1

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. 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.

Siu, Stanley C. (Castro Valley, CA); Evans, James W. (Piedmont, CA)

1998-01-01

2

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

3

Power hydraulics - switched mode control of hydraulic actuation  

Microsoft Academic Search

This paper is concerned with the application of switching technology to hydraulic actuation. Over the last 50 years with advances in power electronics, faster and faster static switches have been developed and applied to the control of motors. Hydraulic technology evolved in the opposite direction: switching control was not considered, and more and more accurate proportional flow\\/pressure control devices (servovalves

Emanuele Guglielmino; Claudio Semini; Helmut Kogler; Rudolf Scheidl; Darwin G. Caldwell

2010-01-01

4

Thermal Hydraulic Analysis of a Packed Bed Reactor Fuel Element.  

National Technical Information Service (NTIS)

A model of the behavior of a packed bed nuclear reactor fuel element is developed. It is capable of predicting the temperature, pressure and velocity fields as a function of position throughout the fuel element in both transient and steady state condition...

R. S. Tuddenham

1989-01-01

5

Autoerotic fatalities with power hydraulics.  

PubMed

We report two cases in which men used the hydraulic shovels on tractors to suspend themselves for masochistic sexual stimulation. One man developed a romantic attachment to a tractor, even giving it a name and writing poetry in its honor. He died accidentally while intentionally asphyxiating himself through suspension by the neck, leaving clues that he enjoyed perceptual distortions during asphyxiation. The other man engaged in sexual bondage and transvestic fetishism, but did not purposely asphyxiate himself. He died when accidentally pinned to the ground under a shovel after intentionally suspending himself by the ankles. We compare these cases with other autoerotic fatalities involving perceptual distortion, cross-dressing, machinery, and postural asphyxiation by chest compression. PMID:8454997

O'Halloran, R L; Dietz, P E

1993-03-01

6

Hydraulic Wind Power Transfer Technology Afshin Izadian  

E-print Network

high cost of wind energy and technological dependency on countries such as China and Germany. ReducingHydraulic Wind Power Transfer Technology Afshin Izadian Purdue School of Engineering and Technology, Department of Engineering Technology Indiana University ­ Purdue University Indianapolis Abstract: Expiration

Zhou, Yaoqi

7

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

8

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

9

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

10

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

11

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

2006-12-14

12

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

13

Power cylinders in the hydraulic drives of machine tools  

Microsoft Academic Search

Numerous executive operations are performed in high-speed hydraulic machine tools and automatic lines, using bulk hydraulic drives [1]. These operations are accomplished by hydromechanical positioning devices that best meet the requirements regarding the executive operations in machine tools: high power combined with small size and mass; kinematic rigidity; excellent dynamic performance; and the possibility of constructing complex systems by simple

V. V. Burenin

2009-01-01

14

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

15

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

16

Hybrid hydraulic-electric power unit for field and service robots  

Microsoft Academic Search

Energetic autonomy of a hydraulic-based mobile field robot requires a power source capable of both electrical and hydraulic power generation. While the hydraulic power is used for locomotion, the electric power is used for the computer, sensors and other peripherals. An internal combustion engine was used as the prime mover due to the high energy density of gasoline. The primary

Kurt Amundson; Justin Raade; Nathan Harding; H. Kazerooni

2005-01-01

17

49 CFR 173.172 - Aircraft hydraulic power unit fuel tank.  

...hydraulic power unit fuel tank. Aircraft hydraulic power unit fuel tanks containing a mixture of anhydrous hydrazine and monomethyl hydrazine (M86 fuel) and designed for installation as complete units in aircraft are excepted from the...

2014-10-01

18

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 controlmaterials...flanges, and standard valves) for hydraulic or pneumatic power and control...

2010-10-01

19

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Hydraulic or pneumatic power and control-materials and pressure...Pressure Design 128.240 Hydraulic or pneumatic power and controlmaterials and pressure...and standard valves) for hydraulic or pneumatic power and control systems must...

2013-10-01

20

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Hydraulic or pneumatic power and control-materials and pressure...Pressure Design 128.240 Hydraulic or pneumatic power and controlmaterials and pressure...and standard valves) for hydraulic or pneumatic power and control systems must...

2012-10-01

21

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

22

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.

23

Hydraulic landscapes and imperial power in the Near East  

Microsoft Academic Search

Over the past 20years archaeological surveys and remote sensing have contributed significantly to the discovery of ancient\\u000a hydraulic systems in the Middle East. The significance of this increase, namely in the scale and number of canals, conduits\\u000a and qanats, is examined and related to the role of power and the administration of the later territorial empires which date\\u000a from the

Tony James Wilkinson; Louise Rayne

2010-01-01

24

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 Proportional-integral with velocity feedforward force controller [1] works well in the con- strained space

Li, Perry Y.

25

The hydraulic design of pump turbine for Xianyou pumped storage power station  

NASA Astrophysics Data System (ADS)

This paper presents the hydraulic design of pump turbines for Xianyou pumped storage power station. The method of improving the hydraulic performance of pump turbine with CFD analysis is given. The results of model test indicate that the final hydraulic design of pump turbine for Xianyou pumped storage power station is of high efficiencies, good

Zheng, J. S.; Liu, W. C.; Fu, Z. Y.; Shi, Q. H.

2012-11-01

26

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

Code of Federal Regulations, 2013 CFR

...uses a hydraulic system common to more...emergency lighting and power system. (d) The motor-driven...continuous deck, and be controlled from above the uppermost...f) The source of power for each hydraulically...operated watertight door system using an...

2013-10-01

27

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

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Electric and hydraulic power supply. 111.97-5...SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems...

2012-10-01

28

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

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Electric and hydraulic power supply. 111.97-5...SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems...

2011-10-01

29

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

Code of Federal Regulations, 2011 CFR

...pneumatic power and control-materials and pressure design. 128.240 Section 128...EQUIPMENT AND SYSTEMS Materials and Pressure Design 128.240 Hydraulic or pneumatic power and controlmaterials and pressure design. (a) Each standard...

2011-10-01

30

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.

31

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

32

Research on Discharge Circuit of Electro-Hydraulic Power Impulse Water Jets  

NASA Astrophysics Data System (ADS)

Electro-hydraulic power impulse water jets can convert the shock wave generated in the liquid by discharging into mechanical energy, and it has been widely used in material forming, surface cleaning, pipeline dirt cleaning and ore breaking process. Compared with the traditional high pressure water jets, the energy utilization of electro-hydraulic power impulse water jets is up to 80% while the water consumption is reduced by 40-55%. This paper has taken electro-hydraulic power impulse water jets as the research object, employed obtaining the maximum pressure of compression impulse matrix surface as the research goal, studied in depth the equivalent discharge circuit, characteristic equation and the relationship between the electrical parameters of the electro-hydraulic power impulse discharge circuit and built the calculation method of the voltage, the inductance, the capacitance and the electrode spacing parameter of electro-hydraulic power impulse water jets discharge circuit. So, it will provide important theoretical basis for further studies of electro-hydraulic power impulse technology and the existing water jets device.

Wang, Zhaohui; Gao, Quanjie; Wang, Wei; Liao, Zhenfang

2012-12-01

33

The Production of Electrochromatography Capillary Columns Using Gas Pressure Powered Dry-Packing Method  

Microsoft Academic Search

This paper introduces a dry-packing method of producing packed capillaries for using in capillary electrochromatography (CEC) or microbore HPLC. Several C18 packing materials with different particle size are studied. We compared the two methods of dry-packing and slurry-packing. The former yields analogous or better efficiency with a simpler apparatus using a shorter packing time. Besides, the columns are very stable

Changqiao Zhang; Chenfu Zhu; Xiuli Lin; Yunhe Wei

2003-01-01

34

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 57min 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 3.8L(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 500We at full power simultaneously, while the fuel cell alone provides 150-200We 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

35

Optimal Power Management for a Hydraulic Hybrid Delivery Truck  

E-print Network

demonstrate characteristics that are very different fromtheir electric counterparts, thus requiring unique characteristics of hydraulic components, and minimizes disadvantages of low energy density, to achieve enhanced faster rate than that of passenger cars. This is a consequence of increased proportion of light trucks

Peng, Huei

36

Power generation by packed-bed air-cathode microbial fuel cells.  

PubMed

Catalysts and catalyst binders are significant portions of the cost of microbial fuel cell (MFC) cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. Packed-bed air-cathodes were constructed without expensive binders or diffusion layers using four inexpensive carbon-based materials. Cathodes made from activated carbon produced the largest maximum power density of 676 93 mW/m(2), followed by semi-coke (376 47 mW/m(2)), graphite (122 14 mW/m(2)) and carbon felt (60 43 mW/m(2)). Increasing the mass of activated carbon and semi-coke from 5 to ? 15 g significantly reduced power generation because of a reduction in oxygen transfer due to a thicker water layer in the cathode (?3 or ?6 cm). These results indicate that a thin packed layer of activated carbon or semi-coke can be used to make inexpensive air-cathodes for MFCs. PMID:23732924

Zhang, Xiaoyuan; Shi, Juan; Liang, Peng; Wei, Jincheng; Huang, Xia; Zhang, Chuanyi; Logan, Bruce E

2013-08-01

37

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.

38

Resin Liner Recovery and Over-Packing at Ontario Power Generation's Western Waste Management Facility  

SciTech Connect

Spent resins generated from Ontario Power Generation (OPG)'s and Bruce Power's Candu reactor operations are stored at OPG's Western Waste Management Facility in Kincardine, Ontario, Canada. The older resins are contained in 3 m{sup 3} epoxy-coated cylindrical carbon steel containers known as resin liners. The liners are stored in a stacked configuration within cylindrical in-ground containers. Previous studies indicated evidence of unacceptable liner wall corrosion and the potential for eventual leakage of resin from the liners. Based on this, OPG elected to re-package the majority of the resin liners into stainless steel over-packs. A contract for this work was awarded to a project team consisting of Duratek of Canada, Kinectrics, Inc. and E.S. Fox. This paper provides an overall summary of project activities focusing on the effectiveness of the equipment utilized and the soundness of the developed programs, plans and procedures. Specific information is provided on key aspects of the project and the overall achievement of project goals. (authors)

Pearson, S.D. [EnergySolutions, Columbia, SC (Colombia); Husain, A. [Kinectrics, Toronto, Ontario (Canada)

2008-07-01

39

LVP modeling and dynamic characteristics prediction of a hydraulic power unit in deep-sea  

NASA Astrophysics Data System (ADS)

A hydraulic power unit (HPU) is the driving "heart" of deep-sea working equipment. It is critical to predict its dynamic performances in deep-water before being immerged in the seawater, while the experimental tests by simulating deep-sea environment have many disadvantages, such as expensive cost, long test cycles, and difficult to achieve low-temperature simulation, which is only used as a supplementary means for confirmatory experiment. This paper proposes a novel theoretical approach based on the linear varying parameters (LVP) modeling to foresee the dynamic performances of the driving unit. Firstly, based on the varying environment features, dynamic expressions of the compressibility and viscosity of hydraulic oil are derived to reveal the fluid performances changing. Secondly, models of hydraulic system and electrical system are accomplished respectively through studying the control process and energy transfer, and then LVP models of the pressure and flow rate control is obtained through the electro-hydraulic models integration. Thirdly, dynamic characteristics of HPU are obtained by the model simulating within bounded closed sets of varying parameters. Finally, the developed HPU is tested in a deep-sea imitating hull, and the experimental results are well consistent with the theoretical analysis outcomes, which clearly declare that the LVP modeling is a rational way to foresee dynamic performances of HPU. The research approach and model analysis results can be applied to the predictions of working properties and product designs for other deep-sea hydraulic pump.

Cao, Xue-peng; Ye, Min; Deng, Bin; Zhang, Cui-hong; Yu, Zu-ying

2013-03-01

40

Fuel Cell-Shaft Power Packs (FC-SPP) Frank Elefsen, Centre Manager, Ph.D., and Sten Frandsen, Head of Section  

E-print Network

Fuel Cell-Shaft Power Packs (FC-SPP) Frank Elefsen, Centre Manager, Ph.D., and Sten Frandsen, Head and an improved environment. 1 Fuel Cell-Shaft Power Packs (FC-SPP) A. Background In line with the growing global technology is receiving a great deal of attention. Hydrogen and fuel cells have the potential to replace

41

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

42

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

43

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

44

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

45

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.

Workshop, Watsonville E.

2011-01-01

46

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

47

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

48

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

49

Thermal-hydraulic tests of a recirculation cooling installation for the Rostov nuclear power station  

NASA Astrophysics Data System (ADS)

Results obtained from thermal-hydraulic tests of the recirculation cooling installation used as part of the air cooling system under the containments of the Rostov nuclear power station Units 3 and 4 are presented. The operating modes of the installation during normal operation (air cooling on the surface of finned tubes), under the conditions of anticipated operational occurrences (air cooling and steam condensation from a steam-air mixture), and during an accident (condensation of pure steam) are considered. Agreement is obtained between the results of tests and calculations carried out according to the recommendations given in the relevant regulatory documents. A procedure of carrying out thermal calculation for the case of steam condensation from a steam-air mixture on the surface of fins is proposed. The possibility of efficient use of the recirculation cooling installation in the system for reducing emergency pressure under the containment of a nuclear power station is demonstrated.

Balunov, B. F.; Balashov, V. A.; Il'in, V. A.; Krayushnikov, V. V.; Lychakov, V. D.; Meshalkin, V. V.; Ustinov, A. N.; Shcheglov, A. A.

2013-09-01

50

Thermal-Hydraulic Performance of Cross-Shaped Spiral Fuel in High-Power-Density BWRs  

SciTech Connect

Power up-rating of existing nuclear reactors promises to be an area of great study for years to come. One of the major approaches to efficiently increasing power density is by way of advanced fuel design, and cross-shaped spiral-fuel has shown such potential in previous studies. Our work aims to model the thermal-hydraulic consequences of filling a BWR core with these spiral-shaped pins. The helically-wound pins have a cross-section resembling a 4-petaled flower. They fill an assembly in a tight bundle, their dimensions chosen carefully such that the petals of neighboring pins contact each other at their outer-most extent in a self-supporting lattice, absent of grid spacers. Potential advantages of this design raise much optimism from a thermal-hydraulic perspective. These spiral rods possess about 40% larger surface area than traditional rods, resulting in increased cooling and a proportional reduction in average surface heat flux. The thin petal-like extensions help by lowering thermal resistance between the hot central region of the pin and the bulk coolant flow, decreasing the maximum fuel temperature by 200 deg. C according to Finite Element (COSMOS) models. However, COSMOS models also predict a potential problem area at the 'elbow' region of two adjoining petals, where heat flux peaking is twice that along the extensions. Preliminary VIPRE models, which account only for the surface area increase, predict a 22% increase in critical power. It is also anticipated that the spiral twist would provide the flowing coolant with an additional radial velocity component, and likely promote turbulence and mixing within an assembly. These factors are expected to provide further margin for increased power density, and are currently being incorporated into the VIPRE model. The reduction in pressure drop inherent in any core without grid-spacers is also expected to be significant in aiding core stability, though this has not yet been quantified. Spiral-fuel seems to be a favorable alternative to traditional pins from a thermal-hydraulic standpoint, though further study of the trends shown in this paper are required. (authors)

Conboy, Thomas; Hejzlar, Pavel [Massachusetts Institute of Technology, 77 massachusetts avenue cambridge, ma 02139-4307 (United States)

2006-07-01

51

The Combined Operation of Steam and Hydraulic Power in the Pennsylvania Water and Power Company System  

Microsoft Academic Search

The paper relates the experience of a large hydroelectric development on an erratic river, in endeavoring to accomplish most effective combined steam and hydroelectric operation, indicating that a river may be developed to an extent many times its low water flow where there is extended cooperation between customer and power company in determining, by experimenting, the economy of further supply

John Abbet Walls

1915-01-01

52

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 Nuveras 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-Bs 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

53

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...

2009-07-22

54

An integrated power pack of dye-sensitized solar cell and Li battery based on double-sided TiO2 nanotube arrays.  

PubMed

We present a new approach to fabricate an integrated power pack by hybridizing energy harvest and storage processes. This power pack incorporates a series-wound dye-sensitized solar cell (DSSC) and a lithium ion battery (LIB) on the same Ti foil that has double-sided TiO(2) nanotube (NTs) arrays. The solar cell part is made of two different cosensitized tandem solar cells based on TiO(2) nanorod arrays (NRs) and NTs, respectively, which provide an open-circuit voltage of 3.39 V and a short-circuit current density of 1.01 mA/cm(2). The power pack can be charged to about 3 V in about 8 min, and the discharge capacity is about 38.89 ?Ah under the discharge density of 100 ?A. The total energy conversion and storage efficiency for this system is 0.82%. Such an integrated power pack could serve as a power source for mobile electronics. PMID:22519631

Guo, Wenxi; Xue, Xinyu; Wang, Sihong; Lin, Changjian; Wang, Zhong Lin

2012-05-01

55

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

56

Packed Lunches.  

E-print Network

and vegetables varie~ dccording to season. During certain times of the year, eggs and some meats are also scarcer and more expensive. 3 Ham and cheese sandwich Carrot and celery strips Apple Iced tea or hot coffee Brown Bag Menu Frui~ Bread- Milk Meat... butter, nut spreads and egg yol k mixtures. Pack frozen in lunch box. Set aside areas in your refrigerator, freezer an cup- boards for lunch box foods, wrappings and contai for quick lunch preparations. To avoid the morning rush, pack lunch...

Reasonover, Frances L.

1982-01-01

57

Bin Packing  

E-print Network

and is able to break symmetry completely. The proposed ... Email addresses: fdabrandao@dcc.fc.up.pt (Filipe Brandao), jpp@fc.up.pt (Joao Pedro. Pedroso) ... In this section we will give account of previous approaches to bin packing and.

Filipe Brandao

2012-04-13

58

Hydraulic Transport of Ice-Water Mixtures  

NASA Astrophysics Data System (ADS)

When an ice thermal storage system is introduced into a district cooling system,the hydraulic ice transport system must have an advantage over a conventional water transport system in saving pipe sizes and pumping powers. Referring to the literature providing direct information on the hydraulic transport of ice-water mixtures,the author comments on the following subjects : Definitions of an ice packing factor. The capacity of heat transported with ice-water mixtures. District distribution system. Flow patterns in ice-water two-phase flow in straight pipes. General expressions for pressure losses in solid-liquid two-phase flow. The characteristics of pressure losses in ice-water two-phase flow. Choking phenomena in channels.

Fujita, Toshihiko

59

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

60

Hydraulic fracturing  

E-print Network

Hydraulic fracturing (also hydrofracturing, hydrofracking, fracking, or fraccing) is a well-stimulation technique in which rock is fractured by a hydraulically pressurized liquid. Some hydraulic fractures form naturallycertain veins or dikes are examp...

61

Method for dense packing discovery.  

PubMed

The problem of packing a system of particles as densely as possible is foundational in the field of discrete geometry and is a powerful model in the material and biological sciences. As packing problems retreat from the reach of solution by analytic constructions, the importance of an efficient numerical method for conducting de novo (from-scratch) searches for dense packings becomes crucial. In this paper, we use the divide and concur framework to develop a general search method for the solution of periodic constraint problems, and we apply it to the discovery of dense periodic packings. An important feature of the method is the integration of the unit-cell parameters with the other packing variables in the definition of the configuration space. The method we present led to previously reported improvements in the densest-known tetrahedron packing. Here, we use the method to reproduce the densest-known lattice sphere packings and the best-known lattice kissing arrangements in up to 14 and 11 dimensions, respectively, providing numerical evidence for their optimality. For nonspherical particles, we report a dense packing of regular four-dimensional simplices with density ?=128/219?0.5845 and with a similar structure to the densest-known tetrahedron packing. PMID:21230619

Kallus, Yoav; Elser, Veit; Gravel, Simon

2010-11-01

62

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 H-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; Garca-Naranjo, Juan C

2014-01-01

63

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

64

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

65

Bin Packing  

E-print Network

revious weaker bounds) actually holds for randomized algorithms against oblivious adversary. On the other hand, the best known deterministic algorithm is the 1:5888competitive HARMONIC+1 by Richey [8] which groups packets by size into more than 70 categories which are then packed independently. We will see next that a few simple greedy algorithms do not perform much worse. ffl Next-Fit (NF): There is always at most one active bin. If the next packet fits into the active bin, we add it to the active bin. Otherwise, the active bin is closed (and never used again) and we put the packet into a new bin which then becomes the new active bin. ffl First-Fit (FF): As we fill the bins, we number them 1; 2; 3; : : :. The next packet is then stored in the lowest-indexed bin which still has enough free capacity (or in a new bin if all bins are to

In The Bin

66

Thermo-Hydraulic Performance And High Power Transmission Characteristics Of The RS Torus Window Prototype  

Microsoft Academic Search

High power CVD-diamond torus windows being the 1 st tritium barrier of the ECRH upper port launcher should be able to provide continues transmission of 2 MW power beam at 170 GHz. Heating of the window due to power absorption in CVD diamond disk of about 0.1% of total power induces thermal (secondary) stresses. Moreover the mm-wave optic of the

I. Danilov; R. Heidinger; A. Meier; B. Piosczyk; M. Schmid; W. Bongers; M. Graswinckel; B. Lamers; A. G. A. Verhoeven

67

Automatic Differentiation: A Powerful Device for the Estimation of Hydraulic Parameters  

NASA Astrophysics Data System (ADS)

Our aim is to estimate the hydraulic transmission parameter T, in the confined aquifer equation: [1] ? / ? x}( T ? h} / ? x}) + ? / ? y}( T ? h} / ? y})=S ? h} / ? t}+q, which is typical case of an ill posed inverse problem. A widely used strategy to solve (1) in practice is to estimate T as the T0 solution of a certain kind of a nonlinear optimization problem such as: [2] minT F(T), F(T)= | hk(T)-h0 |2, where h0 is a real observations vector and hk(T) is the solution of (1) related to the actual Tk solution of (2), obtained by some iterative process. We shall present computational results of estimating T for the cuban Ariguanabo aquifer, emphasizing the use of automatic differentiation to solve the optimization problem (2), by comparing this alternative with the use of the divided differences method.

Alvarez, R. M.; Guerrero, J.

2008-12-01

68

Packed Bed Reactor Experiment  

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 ...

69

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

Code of Federal Regulations, 2010 CFR

...111.97-5 Section 111.97-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems ...

2010-10-01

70

Paper Number Sizing and Optimal Operation of a Power Split Hydraulic  

E-print Network

Y. Li Center for Compact and Efficient Fluid Power University of Minnesota ABSTRACT Hybrid drive components are selectively shut-off are proposed to improve fuel economy. Significant improvements in fuel configurations can be found on the market today. The electric hybrid technology, where the battery operates

Li, Perry Y.

71

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

2013-07-18

72

Pack a more powerful punch and lay the pipe: erectile enhancement discourse as a body project for masculinity  

Microsoft Academic Search

In this article, we analyze erectile enhancement as a postmodern body project that (re)codes hegemonic masculinity through new means. Erectile enhancement Internet ads create a text of masculinity through constructing a crisis of masculinity and selling the solution. The crisis is loss of power, control and the ability to dominate; the solution is a larger and more powerful penis that

Sarah Jane Brubaker; Jennifer A. Johnson

2008-01-01

73

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

74

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

75

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

E-print Network

- ing approach by which the weighted Hamming distance between the blocks activities is considered. After. Once the activity profiles are realized, sleep transistors are carefully positioned to contain-Vth (HVT) sleep transistors (STs) to cut off a low-Vth circuit from the power rails during the standby mode

Boyer, Edmond

76

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

77

Carbonization and activation of inexpensive semicoke-packed electrodes to enhance power generation of microbial fuel cells.  

PubMed

A simple and low-cost modification method was developed to improve the power generation performance of inexpensive semicoke electrode in microbial fuel cells (MFCs). After carbonization and activation with water vapor at 800-850?C, the MFC with the activated coke (modified semicoke) anode produced a maximum power density of 74 Wm(-3) , 17 Wm(-3) , and 681 mWm(-2) (normalized to anodic liquid volume, total reactor volume, and projected membrane surface area, respectively), which was 124 % higher than MFCs using a semicoke anode (33 Wm(-3) , 8 Wm(-3) , and 304 mWm(-2) ). When they were used as biocathode materials, activated coke produced a maximum power density of 177 Wm(-3) , 41 Wm(-3) , and 1628 mWm(-2) (normalized to cathodic liquid volume, total reactor volume, and projected membrane surface area, respectively), which was 211 % higher than that achieved by MFCs using a semicoke cathode (57 Wm(-3) , 13 Wm(-3) , and 524 mWm(-2) ). A substantial increase was also noted in the conductivity, C/O mass ratio, and specific area for activated coke, which reduced the ohmic resistance, increased biomass density, and promoted electron transfer between bacteria and electrode surface. The activated coke anode also produced a higher Coulombic efficiency and chemical oxygen demand removal rate than the semicoke anode. PMID:22639403

Wei, Jincheng; Liang, Peng; Zuo, Kuichang; Cao, Xiaoxin; Huang, Xia

2012-06-01

78

Approximate strip packing  

SciTech Connect

We present an approximation scheme for strip-packing, or packing rectangles into a rectangle of fixed width and minimum height, a classical NP-hard cutting-stock problem. The algorithm finds a packing of n rectangles whose total height is within a factor of (1 + {epsilon}) of optimal, and has running time polynomial both in n and in 1/{epsilon}. It is based on a reduction to fractional bin-packing, and can be performed by 5 stages of guillotine cuts.

Kenyon, C. [CNRS, Lyon (France); Remila, E. [LASPI, Roanne (France)

1996-12-31

79

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

80

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.

81

A method for dense packing discovery  

E-print Network

The problem of packing a system of particles as densely as possible is foundational in the field of discrete geometry and is a powerful model in the material and biological sciences. As packing problems retreat from the reach of solution by analytic constructions, the importance of an efficient numerical method for conducting \\textit{de novo} (from-scratch) searches for dense packings becomes crucial. In this paper, we use the \\textit{divide and concur} framework to develop a general search method for the solution of periodic constraint problems, and we apply it to the discovery of dense periodic packings. An important feature of the method is the integration of the unit cell parameters with the other packing variables in the definition of the configuration space. The method we present led to improvements in the densest-known tetrahedron packing which are reported in [arXiv:0910.5226]. Here, we use the method to reproduce the densest known lattice sphere packings and the best known lattice kissing arrangements in up to 14 and 11 dimensions respectively (the first such numerical evidence for their optimality in some of these dimensions). For non-spherical particles, we report a new dense packing of regular four-dimensional simplices with density $\\phi=128/219\\approx0.5845$ and with a similar structure to the densest known tetrahedron packing.

Yoav Kallus; Veit Elser; Simon Gravel

2010-03-17

82

Hydraulic calipers  

NASA Technical Reports Server (NTRS)

Hydraulic calipers determine area of annular openings in irregular or concealed passages. With modifications the device could be adapted to investigations of cross-sectional changes in heat flow passages, ducts, conduits, and heat exchanger elements.

Benson, J. A.

1969-01-01

83

Missile Roll Control We wish to design a feedback controller for a missile, using hydraulic-powered ailerons, that will  

E-print Network

Missile Roll Control We wish to design a feedback controller for a missile, using hydraulic several potential designs before reaching a final design. (Consider at least proportional feedback and proportional-plus-derivative feedback.) You should turn in the following: 1) a complete discussion of all

Hagan, Martin

84

Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs  

Microsoft Academic Search

Battery management systems in hybrid electric vehicle battery packs must estimate values descriptive of the packs present operating condition. These include: battery state of charge, power fade, capacity fade, and instantaneous available power. The estimation mechanism must adapt to changing cell characteristics as cells age and therefore provide accurate estimates over the lifetime of the pack.In a series of three

Gregory L. Plett

2004-01-01

85

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

86

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.

87

Measuring Frac-pack Conductivity at Reservoir Temperature and High Closure Stress  

E-print Network

Ultra-deepwater reservoirs are important non-conventional reservoirs that hold the potential to produce billions of barrels of hydrocarbons but present major challenges. Hydraulic fracturing or frac-packing high permeability reservoirs is different...

Fernandes, Preston X.

2010-10-12

88

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.

89

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

90

Nasal packing after septoplasty.  

PubMed

A prospective study to compare 3 different types of nasal pack after septoplasty with or without a supplementary turbinectomy has been performed with respect to discomfort and complications caused by the packing and the short-term results evaluated 3 months after operation. Fingerstall packings gave less problems than either Merocel or hydrocortisone-terramycine gauze packs with ventilation tubes. They were easier to remove and were associated with less persistent secretion in the post-operative period. No definite advantage from the patient's point of view has been demonstrated by the use of tubes and nasal packing. An analysis of the nasal patency 3 months post-operatively by peak-flow index and acoustic rhinometry revealed no differences between groups. PMID:1587033

Illum, P; Grymer, L; Hilberg, O

1992-04-01

91

Active (air-cooled) vs. passive (phase change material) thermal management of high power lithium-ion packs: Limitation of temperature rise and uniformity of temperature distribution  

Microsoft Academic Search

The effectiveness of passive cooling by phase change materials (PCM) is compared with that of active (forced air) cooling. Numerical simulations were performed at different discharge rates, operating temperatures and ambient temperatures of a compact Li-ion battery pack suitable for plug-in hybrid electric vehicle (PHEV) propulsion. The results were also compared with experimental results. The PCM cooling mode uses a

Rami Sabbah; R. Kizilel; J. R. Selman; S. Al-Hallaj

2008-01-01

92

Graphitic packing removal tool  

SciTech Connect

Graphitic packing removal tools are described for removal of the seal rings in one piece from valves and pumps. The 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, K.E.; Kolsun, G.J.

1996-12-31

93

Tiber winding pack design  

SciTech Connect

A preliminary winding pack design was performed with the goal of showing feasibility of producing 10-T maximum field with a pack current density of 40 A.mm/sup -2/ while accepting 2.7 kW per coil nuclear heating. A cable-in-conduit conductor design (CIC), reported at the 6th Topical Meeting on the Technology of Fusion Energy, was based on several key issues.

Miller, J.R.

1985-08-19

94

Electric versus hydraulics versus pneumatics  

SciTech Connect

This book presents a collection of papers from a conference which considered the advantages and disadvantages of electric, hydraulic and pneumatic drives and actuators. The volume follows on the success of the 1983 conference on electric and hydraulic drives. Topics considered include fork lift trucks - an ideal application for regenerative transmissions; a hybrid-electric power system with hydrostatic transmission; electrics and hydraulics on roadheader machinery; hydraulic, electrical, pneumatic control - which way to go. an electrically-powered servo to drive the two axes of a missile launching platform - pros and cons when compared with the traditional hydraulic solution; the encapsulation of a novel intrinsically safe displacement transducer; mobile cryogenic pumping systems; automation of a wood-turning machine, hydraulic or electric. The choice of a servo motor for a specific application; developments in the design and control of pneumatic linear actuators; compressed air purification for instrumentation in the high technology industries; trends in prime mover choice for powered hand tools; and choosing the drive system for the right application.

Not Available

1985-01-01

95

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

96

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

97

Hydraulic controls of summer Arctic pack ice albedo  

Microsoft Academic Search

Linkages between albedo, surface morphology, melt pond distribution, and properties of first-year and multiyear sea ice have been studied at two field sites in the North American Arctic between 1998 and 2001. It is shown that summer sea-ice albedo depends critically on surface melt-pond hydrology, controlled by melt rate, ice permeability, and topography. Remarkable short-term and interannual variability in pond

H. Eicken; T. C. Grenfell; D. K. Perovich; J. A. Richter-Menge; K. Frey

2004-01-01

98

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

99

Fireproof Brake Hydraulic System.  

National Technical Information Service (NTIS)

The feasibility of a fireproof two-fluid brake hydraulic system which utilizes nonflammable chlorotrifluoroethylene (CTFE) fluid in a dead ended brake hydraulic system mechanically isolated from the primary MIL-H-5606 hydraulic system was studied. Experim...

S. M. Warren, J. R. Kilner

1981-01-01

100

Fireproof Hydraulic Brake System.  

National Technical Information Service (NTIS)

The Fireproof Hydraulic Brake System (FHBS) flight test program verified that the FHBS is a feasible method of eliminating aircraft hydraulic fluid fires ignited by hot brakes. The FHBS uses a new nonflammable hydraulic fluid, chlorotrifluoroethylene (CTF...

M. W. Dillard

1986-01-01

101

46 CFR 112.50-3 - Hydraulic starting.  

Code of Federal Regulations, 2012 CFR

...SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets 112.50-3 Hydraulic starting. A hydraulic starting system must meet the...

2012-10-01

102

46 CFR 112.50-3 - Hydraulic starting.  

Code of Federal Regulations, 2011 CFR

...SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets 112.50-3 Hydraulic starting. A hydraulic starting system must meet the...

2011-10-01

103

46 CFR 112.50-3 - Hydraulic starting.  

Code of Federal Regulations, 2013 CFR

...SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets 112.50-3 Hydraulic starting. A hydraulic starting system must meet the...

2013-10-01

104

Professional Training Information Pack  

E-print Network

Intending 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 must talk to Dr J. M. Thompson immediately. General introduction to professional training Students

Davies, Christopher

105

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

106

Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs  

Microsoft Academic Search

Battery management systems in hybrid-electric-vehicle battery packs must estimate values descriptive of the packs present operating condition. These include: battery state-of-charge, power fade, capacity fade, and instantaneous available power. The estimation mechanism must adapt to changing cell characteristics as cells age and therefore provide accurate estimates over the lifetime of the pack.In a series of three papers, we propose methods,

Gregory L. Plett

2004-01-01

107

Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs  

Microsoft Academic Search

Battery management systems (BMS) in hybrid-electric-vehicle (HEV) battery packs must estimate values descriptive of the packs present operating condition. These include: battery state of charge, power fade, capacity fade, and instantaneous available power. The estimation mechanism must adapt to changing cell characteristics as cells age and therefore provide accurate estimates over the lifetime of the pack.In a series of three

Gregory L. Plett

2004-01-01

108

Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs  

Microsoft Academic Search

Abstract Battery management,systems in hybrid-electric-vehicle battery packs must estimate values descriptive of the packs present operating condition. These include: battery state-of-charge, power fade, capacity fade, and instantaneous available power. The estimation mechanism must adapt to changing,cell characteristics as cells age and therefore provide accurate estimates over the lifetime of the pack. In a series of three papers, we propose methods,

Gregory L. Plett

109

Converter Structure-Based Power Loss and Static Thermal Modeling of The Press-Pack IGBT Three-Level ANPC VSC Applied to Multi-MW Wind Turbines  

Microsoft Academic Search

Wind turbine converters demand high power den- sity due to nacelle space limitation and high reliability due to high maintenance cost. Depending on the converter structure, the converter thermal performance determines the converter power density and reliability. To estimate the converter thermal per- formance, the converter structure-based power loss and thermal models are developed in this study for the medium-voltage

Osman S. Senturk; Lars Helle; Stig Munk-Nielsen; Pedro Rodriguez; Remus Teodorescu

2011-01-01

110

Optimization of blended battery packs  

E-print Network

This thesis reviews the traditional battery pack design process for hybrid and electric vehicles, and presents a dynamic programming (DP) based algorithm that eases the process of cell selection and pack design, especially ...

Erb, Dylan C. (Dylan Charles)

2013-01-01

111

Robot Intelligence Leslie Pack Kaelbling  

E-print Network

Robot Intelligence Leslie Pack Kaelbling MIT CSAIL #12;A dream of robots Commercial reality Research frontier Leslie Pack Kaelbling, AAAI2010 #12;Robots and AI in artificial intelligence: planning, learning, reasoning, vision, natural language.... Leslie

Willsky, Alan S.

112

Modeling of a novel 3-way rotary type electro-hydraulic valve  

Microsoft Academic Search

Hydraulic actuation is characterized by fast dynamics, high power density, high stiffness, large output force\\/torque, and in recent years it has become an increasing attractive form of robot actuation. Hydraulic control valves that not only provide the interface between hydraulic power element and actuators, but also receive feedback signal and adjust the system output accordingly, are key components of hydraulic

Yousheng Yang; Emanuele Guglielmino; Jian S. Dai; Thiago Boaventura; Darwin G. Caldwell

2010-01-01

113

Universal Aircraft Seat Pack  

NASA Astrophysics Data System (ADS)

1 data display. Commands to the balloon are sent either by the computer or manually via thumb- wheels and the associated command encoder located on the front panel. The front panel commanding is backup for the computer commanding. Two redundant UHF command transmitters are used for up-link commanding to the balloon payload. Other Seat Pack features include an LDB Imarsat system for satellite data relay and a voice transceiver for air to ground voice communications with the operations center.

Barsic, J.; Depue, J.; Hadley, J.; Bunt, D.; Salter, R.

114

Promoting water hydraulics in Malaysia: A green educational approach  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

115

Development of the Packed Bed Reactor ISS Flight Experiment.  

National Technical Information Service (NTIS)

Packed bed reactors are compact, require minimum power and maintenance to operate, and are highly reliable. These features make this technology a leading candidate as a potential unit operation in support of long duration human space exploration. On earth...

A. E. Bruzas, B. J. Motil, E. Rame, M. O. Patton

2012-01-01

116

Adaptive multiple texture approach to texture packing for 3D video games  

Microsoft Academic Search

This paper presents an adaptive multiple texture approach to the problem of texture packing for 3D video games. In modern graphics hardware, texture size is typically constrained to width and height dimensions that are powers of two. To reduce the texture management overhead caused by storing individual textures, texture packing algorithms are used to pack multiple textures into a single

Alexander Wong; Andrew Kennings

2007-01-01

117

Dense periodic packings of tori  

E-print Network

Dense packings of nonoverlapping bodies in three-dimensional Euclidean space are useful models of the structure of a variety of many-particle systems that arise in the physical and biological sciences. Here we investigate the packing behavior of congruent ring tori, which are multiply connected nonconvex bodies of genus 1, as well as horn and spindle tori. We analytically construct a family of dense periodic packings of unlinked tori guided by the organizing principles originally devised for simply connected solid bodies [Torquato and Jiao, PRE 86, 011102 (2012)]. We find that the horn tori as well as certain spindle and ring tori can achieve a packing density higher than the densest known packing of both sphere and ellipsoids. In addition, we study dense packings of cluster of pair-linked ring tori (i.e., Hopf links).

Ruggero Gabbrielli; Yang Jiao; Salvatore Torquato

2014-02-26

118

*sja@iet.aau.dkwww.iet.aau.dk Development of a 400 W High Temperature PEM Fuel Cell Power Pack : Fuel Cell Stack Test  

E-print Network

temperature PEM (HTPEM) fuel cells has great advantages when using reformate fuel gas compared to low voltage drop, and hereby a power loss because of the lower temperature. The design of the gas channels primary drawback being the temperature gradient in the stack and a long start-up time because the system

Berning, Torsten

119

Multilayer DNA Origami Packed on Hexagonal and Hybrid Lattices  

PubMed Central

Scaffolded DNA origami has been proven to be a powerful and efficient approach to construct two-dimensional or three-dimensional objects with great complexity. Multilayer DNA origami has been demonstrated with helices packing along either honeycomb-lattice geometry or square-lattice geometry. Here we report successful folding of multilayer DNA origami with helices arranged on a close-packed hexagonal lattice. This arrangement yields a higher density of helical packing and therefore higher resolution of spatial addressing than has been shown previously. We also demonstrate hybrid multilayer DNA origami with honeycomb-lattice, square-lattice, and hexagonal lattice packing of helices all in one design. The availability of hexagonal close packing of helices extends our ability to build complex structures using DNA nanotechnology. PMID:22187940

Ke, Yonggang; Voigt, Niels V.; Gothelf, Kurt V.; Shih, William M.

2012-01-01

120

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

121

Safety and efficiency conflicts in hydraulic architecture: scaling from tissues to trees.  

PubMed

Tree hydraulic architecture exhibits patterns that propagate from tissue to tree scales. A challenge is to make sense of these patterns in terms of trade-offs and adaptations. The universal trend for conduits per area to decrease with increasing conduit diameter below the theoretical packing limit may reflect the compromise between maximizing the area for conduction versus mechanical support and storage. Variation in conduit diameter may have two complementary influences: one being compromises between efficiency and safety and the other being that conduit tapering within a tree maximizes conductance per growth investment. Area-preserving branching may be a mechanical constraint, preventing otherwise more efficient top-heavy trees. In combination, these trends beget another: trees have more, narrower conduits moving from trunks to terminal branches. This pattern: (1) increases the efficiency of tree water conduction; (2) minimizes (but does not eliminate) any hydraulic limitation on the productivity or tissue growth with tree height; and (3) is consistent with the scaling of tree conductance and sap flow with size. We find no hydraulic reason why tree height should scale with a basal diameter to the two-thirds power as recently claimed; it is probably another mechanical constraint as originally proposed. The buffering effect of capacitance on the magnitude of transpiration-induced xylem tension appears to be coupled to cavitation resistance, possibly alleviating safety versus efficiency trade-offs. PMID:18088335

Sperry, John S; Meinzer, Frederick C; McCulloh, Katherine A

2008-05-01

122

Hydraulic core cutting motor  

SciTech Connect

This patent describes an apparatus for drilling core cutting from the sidewall of a drill hole wherein the apparatus comprises an elongated housing with a hydraulic operated back-up shoe mounted within the housing for wedging the housing at a selected location in the drill hole and a hydraulic motor with a drilling bit connected thereto for rotation by the hydraulic motor and hydraulic means mounted within the housing and connected to the hydraulic motor for moving the bit into drilling engagement with the sidewall of the drill hole.

Kilmer, L.G.; Carter, J.W.

1987-11-24

123

Packing Steiner trees Microsoft Research  

E-print Network

@cs.toronto.edu Abstract The Steiner packing problem is to #12;nd the maximum number of edge-disjoint subgraphs of a given Steiner tree problem via the ellipsoid algorithm. 1 Introduction In the Steiner tree packing problem practical as well as theoretical considerations. The problem in its full generality (where for each Steiner

Salavatipour, Mohammad R.

124

Method for gravel packing wells  

SciTech Connect

This patent describes a method for gravel packing a perforated well which penetrates a formation or reservoir. It comprises placing into a solution a shear-thickening composition in an amount sufficient to form a carrier fluid having a viscosity sufficient to suspend gravel packing sand therein for a time sufficient to pack the well; adding gravel packing sand into the fluid thereby suspending the sand therein; injecting the carrier fluid and sand mixture into the well under conditions sufficient to cause the mixture to shear thicken so as to provide for transportation of the sand to perforations in the well without spreading from the mixture; and directing the mixture into the perforations which diminishes shear forces acting on the mixture thereby causing a reduction in viscosity of the carrier fluid, sand separation from the fluid, improved fluid leak-off into the formation, and uniform gravel packing of the perforations.

Yeh, C.S.

1991-12-31

125

Hydro turbine transfer functions with hydraulic coupling  

SciTech Connect

This paper deals with the development of transfer functions for hydraulic turbines connected to a common penstock. These turbines tend to be hydraulically coupled. Both the solid mass approximation and the pressure wave modeling approach are applied for the development of diagonal ([Delta]P[sub mi]/[Delta]g[sub i]) and coupling ([Delta]P[sub mi]/[Delta]g[sub j]) transfer functions. This modeling approach is applied to the Stratos hydro power station of PPC. It is shown that the solid mass approach gives relatively simple rational transfer functions that represent accurately the hydraulic coupling between turbines for a wide frequency range.

Vournas, C.D.; Zaharakis, A. (National Technical Univ., Athens (Greece). Electrical Energy Systems Lab.)

1993-09-01

126

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

127

Dog pack attack: hunting humans.  

PubMed

Dog bite-related fatalities, although unusual, accounted for 304 deaths in the United States between 1979 and 1996 and 6 fatalities in Canada between 1994 and 1996. Fatal dog pack attacks and attacks involving human predation are less common. The following describes a dog pack attack on a family of four involving 2 fatalities with predation of the victims. Factors previously identified that contribute to pack attacks and predation, including prior group hunting, social feeding, territorial defense, lack of human interaction, and prey stimuli, are discussed. PMID:10507791

Avis, S P

1999-09-01

128

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

129

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

130

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

131

Stochastic packing-market planning  

Microsoft Academic Search

Motivated by the problem of centralized market clearing in a mar- ket with probabilistic supply and demand, we introduce the Stochas- tic Packing-Market Planning problem (SPMP), which is a stochas- tic generalization of the Maximum k-Set Packing problem. We provide an O(k) approximation algorithm for SPMP, as well as a O(k) approximation mechanism that is truthful in expectation. This matches

Daniel Golovin

2007-01-01

132

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

133

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

134

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

135

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; Gran Dave

1997-01-01

136

HYDRAULIC CONTROL ROD ACTUATOR  

Microsoft Academic Search

An investigation was made of the conceptual feasibility and production ; of a prototype model of a Hydraulic Control Rod Drive Mechanism that utilizes ; primary reactor water as the hydraulic fluid and is sealed within the reactor ; pressure vessel. It is capable of controlling 2300-pound rods such as might be ; used in large pressurized-water reactors. By utilizing

R. B. Hussey; C. F. Cartledge

1963-01-01

137

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

Sack, Lawren

138

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

139

Nature of packs used in propellant modeling.  

PubMed

In recent years we have constructed closely packed spheres using the Lubachevsky-Stillinger algorithm to generate morphological models of heterogeneous solid propellants. Improvements to the algorithm now allow us to create large polydisperse packs on a laptop computer, and to create monodisperse packs with packing fractions greater than 70% which display significant crystal order. The use of these models in the physical context motivates efforts to examine in some detail the nature of the packs, including certain statistical properties. We compare packing fractions for binary packs with long-known experimental data. Also, we discuss the near-neighbor number and the radial distribution function (RDF) for monodisperse packs and make comparisons with experimental data. We also briefly discuss the RDF for bidisperse packs. We also consider bounded monodisperse packs, and pay particular attention to the near-wall structure where we identify significant order. PMID:18517690

Maggi, F; Stafford, S; Jackson, T L; Buckmaster, J

2008-04-01

140

Packing microstructure and local density variations of experimental and computational pebble beds  

SciTech Connect

In pebble bed type nuclear reactors the fuel is contained in graphite pebbles, which form a randomly stacked bed with a non-uniform packing density. These variations can influence local coolant flow and power density and are a possible cause of hotspots. To analyse local density variations computational methods are needed that can generate randomly stacked pebble beds with a realistic packing structure on a pebble-to-pebble level. We first compare various properties of the local packing structure of a computed bed with those of an image made using computer aided X-ray tomography, looking at properties in the bulk of the bed and near the wall separately. Especially for the bulk of the bed, properties of the computed bed show good comparison with the scanned bed and with literature, giving confidence our method generates beds with realistic packing microstructure. Results also show the packing structure is different near the wall than in the bulk of the bed, with pebbles near the wall forming ordered layers similar to hexagonal close packing. Next, variations in the local packing density are investigated by comparing probability density functions of the packing fraction of small clusters of pebbles throughout the bed. Especially near the wall large variations in local packing fractions exists, with a higher probability for both clusters of pebbles with low (<0.6) and high (>0.65) packing fraction, which could significantly affect flow rates and, together with higher power densities, could result in hotspots. (authors)

Auwerda, G. J.; Kloosterman, J. L.; Lathouwers, D.; Van Der Hagen, T. H. J. J. [Delft Univ. of Technology, Mekelweg 15, 2629 JB, Delft (Netherlands)

2012-07-01

141

Dual hydraulic set packer  

SciTech Connect

This patent describes a hydraulic well packer. It comprises: a tubular body mandrel having a longitudinal flow passage; a seal element assembly movably mounted on the tubular body mandrel; an anchor slip assembly supported by the tubular body mandrel; a hydraulic actuator assembly movably mounted onto the tubular body mandrel, the hydraulic actuator assembly including first and second movable force transmitting means engageable with the seal element assembly and the anchor slip assembly, respectively; the first movable force transmitting means having an axial slip pocket; a locking rod slideably received within the slip pocket, the locking rod being connected to the second movable force transmitting means.

Lane, A.R.; Sproul, R.M.

1990-06-05

142

DESIGN OF INTELLIGENT HYDRAULIC EXCAVATOR CONTROL SYSTEM BASED ON  

E-print Network

DESIGN OF INTELLIGENT HYDRAULIC EXCAVATOR CONTROL SYSTEM BASED ON PID METHOD Jun Zhang 1, an intelligent hydraulic excavator control system was designed based on rotational speed sensing method to improve energy efficiency. The control system was consisted of engine control module, pump power adjusted

143

IOWA INSTITUTE OF HYDRAULIC RESEARCH COLLEGE OF ENGINEERING  

E-print Network

* Hydraulic Model Study of Circulating Water Pump Structure for Marmara Erglisi Power Plant BVI Ettema Erosion Impact Assessment Study for the Upper Mississippi River/Illinois Waterway COE/SENES Oak Ridge ASCE Holly * ** Hydraulic Model Tests of the St. Louis County Water Company Meramec Plant Intakes No. 1

Stanier, Charlie

144

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

145

Ecology and Energy Action Pack.  

ERIC Educational Resources Information Center

One of five McDonald's Action Packs, these elementary school-level instructional materials are for use as an introduction to existing units of study, supplements to a textbook, or a source of special projects for environmental education. Contents include these six units: Make Your Own Ecology Mini-spinner, Let's Look at a Food Chain, Drip the

McDonald's Corp., Oak Brook, IL.

146

Teflon-packed flexible joint  

NASA Technical Reports Server (NTRS)

Teflon-packed flexible joint separates the movement of the shaker from the liquid nitrogen hose during the ground testing of cryogenic zero-g equipment. The joint allows the hose to lie on the floor in a stationary position as the shaker moves back and forth, thus, the hose is not subject to violent motion.

Belmont, G. E.

1969-01-01

147

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

148

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

149

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

150

Vendors for Hero Pack Items  

E-print Network

Program (603) 225-1215 Wing Family Program (603) 430-3545 Operation: Military Kids is a partnership)? When National Guard, Reserve, and other military families living in civilian communities become. Feel free to use either of these resources and/or your own sources for Hero Pack contents. Military

New Hampshire, University of

151

Wire and Packing Tape Sandwiches  

ERIC Educational Resources Information Center

In this article, the author describes how students can combine craft wire with clear packing tape to create a two-dimensional design that can be bent and twisted to create a three-dimensional form. Students sandwich wire designs between two layers of tape. (Contains 1 online resource.)

Rabinowitz, Sandy

2009-01-01

152

The packing factor Animesh Das  

E-print Network

et al. 2005, Reyes and Iglesia 1991). Deformable objects (for example foam) can generate even denser (?berg 1996a, 1996b, Alshibli and El-Saidany 2001). Figure 3: Foams can generate even denser packing. #12. E., The laws of proportioning concrete, Transactions of ASCE, ASCE, Vol. 59, 1907, pp.67

Das, Animesh

153

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

154

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

155

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

E-print Network

-the-shelf proportional valves that are compatible with hydraulic fluid and precise enough for the position control taskPOSITION TRACKING CONTROL OF MINIATURE LOW PRESSURE WATER HYDRAULIC CYLINDERS Russell Sindrey capability. Hydraulic cylinders offer many potential benefits as miniature actuators including: high power

Bone, Gary

156

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.

157

Bridges in three-dimensional granular packings: experiments and simulations  

E-print Network

In this letter, we present the first experimental study of bridge structures in three-dimensional dry granular packings. When bridges are small, they are predominantly 'linear', and have an exponential size distribution. Larger, predominantly 'complex' bridges, are confirmed to follow a power-law size distribution. Our experiments, which use X-ray tomography, are in good agreement with the simulations presented here, for the distribution of sizes, end-to-end lengths, base extensions and orientations of predominantly linear bridges. Quantitative differences between the present experiment and earlier simulations suggest that packing fraction is an important determinant of bridge structure.

Yixin Cao; Bandan Chakrabortty; G. C. Barker; Anita Mehta; Yujie Wang

2011-12-14

158

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

159

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

160

7 CFR 51.1311 - Packing.  

Code of Federal Regulations, 2010 CFR

...tightly packed. All packages shall be well filled but the contents shall not show excessive or unnecessary bruising because of overfilled packages. (c) Pears packed in boxes shall be arranged in containers according to the approved and recognized...

2010-01-01

161

7 CFR 51.1270 - Packing.  

Code of Federal Regulations, 2010 CFR

...tightly packed. All packages shall be well filled but the contents shall not show excessive or unnecessary bruising because of overfilled packages. (c) Pears packed in boxes shall be arranged in containers according to the approved and recognized...

2010-01-01

162

7 CFR 984.15 - Pack.  

Code of Federal Regulations, 2010 CFR

...AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Definitions 984.15 Pack. Pack means to bleach, clean, grade, shell or otherwise prepare walnuts for market as inshell or shelled walnuts. [73 FR 11337, Mar....

2010-01-01

163

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

164

7 CFR 917.13 - Pack.  

Code of Federal Regulations, 2011 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...

2011-01-01

165

7 CFR 906.10 - Pack.  

Code of Federal Regulations, 2010 CFR

...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 means the specific grade,...

2010-01-01

166

7 CFR 966.11 - Pack.  

Code of Federal Regulations, 2012 CFR

...Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2012-01-01

167

7 CFR 966.11 - Pack.  

...NUTS), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2014-01-01

168

7 CFR 966.11 - Pack.  

Code of Federal Regulations, 2011 CFR

...Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2011-01-01

169

7 CFR 966.11 - Pack.  

Code of Federal Regulations, 2010 CFR

...Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2010-01-01

170

7 CFR 966.11 - Pack.  

Code of Federal Regulations, 2013 CFR

...NUTS), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2013-01-01

171

On the kinetics of pack aluminization  

NASA Technical Reports Server (NTRS)

A theory of pack aluminization has been formulated by combining gaseous and solid-state diffusion rates. This theory relates the surface composition of the coating and therefore, in principle, the phase morphology and the growth rate of the coating, to pack operating parameters such as pack aluminum density, type of activator, temperature and others. Experimental data on the aluminization of unalloyed nickel in pure aluminum packs obtained to date are in good agreement with the predictions of the theory.

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

1975-01-01

172

Hydraulic dredging, a sediment removal technique  

SciTech Connect

Sediment was successfully removed from a Peabody Coal Company pond near Macon, Missouri, by a Mud Cat Model SP-810 hydraulic dredge. Previous attempts using land-based equipment had been unsatisfactory. The hydraulic-powered auger and submerged pump easily removed 882 m/sup 3/ (1154 yd/sup 3/) and pumped the slurry a distance of 305 m (1000 ft) to a disposal area. The hydraulic dredge was more effective and cheaper to operate than land-based equipment. The dredge cost was $1.31/m/sup 3/ ($1.00/yd/sup 3/), the dragline cost was $6.54/m/sup 3/ ($5.00/yd/sup 3/) and the front-end loader cost was $15.70/m/sup 3/ ($12.00/yd/sup 3/), under optimum conditions.

Spotts, J.W.

1980-12-01

173

Ant Colony Optimisation for Bin Packing and  

E-print Network

Ant Colony Optimisation for Bin Packing and Cutting Stock Problems Frederick Ducatelle T H E U N I of Informatics University of Edinburgh 2001 #12; Abstract The bin packing and the cutting stock problems are two and evolutionary programming. In this dissertation, I try to solve the bin packing and the cutting stock problem

Ducatelle, Frederick

174

7 CFR 51.1217 - Standard pack.  

Code of Federal Regulations, 2011 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...

2011-01-01

175

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

176

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.

177

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

178

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

179

Effects of packing rates of cubic-shaped polyurethane foam carriers on the microbial community and the removal of organics and nitrogen in moving bed biofilm reactors.  

PubMed

The effects of packing rates (20%, 30%, and 40%) of polyurethane foam (PUF) to the removal of organics and nitrogen were investigated by continuously feeding artificial sewage in three aerobic moving bed biofilm reactors. The results indicated that the packing rate of the PUF carriers had little influence on the COD removal efficiency (81% on average). However, ammonium removal was affected by the packing rates, which was presumably due to the different relative abundances of nitrifying bacteria. A high ammonium removal efficiency of 96.3% at a hydraulic retention time of 5h was achieved in 40% packing rate reactor, compared with 37.4% in 20% packing rate. Microprofiles of dissolved oxygen and nitrate revealed that dense biofilm limits the DO transfer distance and nitrate diffusion. Pyrosequencing analysis of the biofilm showed that Proteobacteria, Bacteroidetes and Verrucomicrobia were the three most abundant phyla, but the proportions of the microbial community varied with the packing rate of the PUF carriers. PMID:22621807

Feng, Quan; Wang, Yuxiao; Wang, Tianmin; Zheng, Hao; Chu, Libing; Zhang, Chong; Chen, Hongzhang; Kong, Xiuqin; Xing, Xin-Hui

2012-08-01

180

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 Lvesque; M Ciureanu; R Roberge; Theodore Motyka

2000-01-01

181

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, ?mR-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

182

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

183

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; Hernn A. Makse

2014-10-08

184

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.

2008-02-07

185

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

186

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

187

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

188

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.

189

Small hydraulic turbine drives  

NASA Technical Reports Server (NTRS)

Turbine, driven by the fluid being pumped, requires no external controls, is completely integrated into the flow system, and has bearings which utilize the main fluid for lubrication and cooling. Torque capabilities compare favorably with those developed by positive displacement hydraulic motors.

Rostafinski, W. A.

1970-01-01

190

Fireproof Hydraulic Brake System.  

National Technical Information Service (NTIS)

The design, development, and manufacture of a flightworthy two-fluid fireproof hydraulic brake system (FHBS) kit for flight testing on a C/KC-135 has been accomplished. The results of system concepts trade studies, the concept selection procedure and rati...

D. W. Huling, F. H. Hillman

1985-01-01

191

DSP Controls Hydraulic Axis  

Microsoft Academic Search

ABSTRACT Advantages are shown by using the DSP for the real time online control of hydraulic axis. The interrupt latency time is the most important factor for equidistant position samples to control the velocity as accurately as possible. The trajectory calculations for the velocity and position are presented as well as their derivation for Scurvatures. The control of the velocity,

Petr Jan Horn

2004-01-01

192

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

193

Battery pack circuit design for safety and protection  

SciTech Connect

Do our fast-paced lifestyles drive new technology, or is new technology partly to blame for continuing to increase the pace of our lifestyles? We want to be connected and productive - or entertained - even during our traditional times of leisure and recreation. Our tools for connectivity and productivity - and our toys for entertainment - support us by continuing to become smaller, lighter and more mobile, even as functionality increases. This drive toward increasing portability, mobility and functionality has had many interesting results. One result is that high-energy battery packs are becoming pervasive in our professional and personal lives. But the high power-delivery and energy-storage capabilities of packs for these power-hungry devices generally remain invisible to end-users. In reality, most packs have the potential not only for damaging themselves, but also for imposing damage on their surroundings, even if used exclusively in accordance with manufacturers` instructions. And newer battery technologies that offer longer runtimes or less weight can pose higher risks. This paper compares and contrasts the characteristics of various safety practices and devices used in designing and assembling high-energy battery packs.

Dewey, M.; Chandler, D.; Tamura, A. [Raychem Corp., Menlo Park, CA (United States)

1995-12-31

194

Cradle modification for hydraulic ram  

SciTech Connect

The analysis of the cradle hydraulic system considers stress, weld strength, and hydraulic forces required to lift and support the cradle/pump assembly. The stress and weld strength of the cradle modifications is evaluated to ensure that they meet the requirements of the American Institute for Steel Construction (AISC 1989). The hydraulic forces are evaluated to ensure that the hydraulic system is capable of rotating the cradle and pump assembly to the vertical position (between 70{degrees} and 90{degrees}).

Koons, B.M.

1995-03-02

195

Hydraulic charcterization of carbonatic rock  

Microsoft Academic Search

The hydraulic conductivity, K(theta), and the water retention, theta(h), are needed to predict the flow of water and solute transport in unsaturated porous media. During recent decades methods have been developed to determine these hydraulic properties for rock. We have developed a methodology, based on Wind's evaporation method for soils, to measure in the laboratory the water retention and hydraulic

M. C. Caputo; A. Basile; R. de Mascellis; J. R. Nimmo; M. Vurro; N. Walsh

2003-01-01

196

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.

197

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

198

Water Resources: Hydraulics and Hydrology  

E-print Network

Water Resources: Hydraulics and Hydrology Interview with Margaret S. Petersen #12;This manuscript RESOURCES: HYDRAULICS AND HYDROLOGY #12;Approved for public release distribution IS unlimited. #12;Preface The United States Army Corps of Engineers significantly contributed to hydraulic and hydrologic engineering

US Army Corps of Engineers

199

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

200

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.

2011-02-14

201

Hydrodynamics of a packed countercurrent column for the gas extraction  

SciTech Connect

The hydraulic capacity of a countercurrent column with gauze packing was examined at pressures between 8 and 30 MPa and temperatures between 313 and 373 K. The systems used were water + carbon dioxide, aqueous surfactant solution + carbon dioxide, and Toco, a substance whose physical properties are roughly similar to those of {alpha}-Tocopherol + carbon dioxide. A distinctive change in the flooding mechanisms from liquid layer flooding to bubble column flooding was observed. The different liquids, water and Toco, showed the same flooding behavior, indicating that the influence of the density on the flooding behavior prevails over the influence of any other physical property of the liquid. The foamability of the surfactant solution decreased significantly with increasing pressure--its influence on the flooding behavior could not be proved. The liquid holdup ranged between 2% and 6%. The dry pressure drop adhered to the Ergun equation.

Stockfleth, R.; Brunner, G.

1999-10-01

202

Predictive control of hydraulic winch motion control  

Microsoft Academic Search

Hydraulic winch is widely used in field of engineering mechanism. Motion control is an important application for hydraulic winch. The hydraulic winch is a mechanism with heavy load and big inertia. The response speed of hydraulic winch deeply affects the controlling precision when the hydraulic winch is in motion control to track a definite motion. Feedforward control of hydraulic winch

Zhou Entao; Yang Wenlin; Lin Junzhe

2009-01-01

203

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

204

The Packing of Granular Polymer Chains  

SciTech Connect

Rigid particles pack into structures, such as sand dunes on the beach, whose overall stability is determined by the average number of contacts between particles. However, when packing spatially extended objects with flexible shapes, additional concepts must be invoked to understand the stability of the resulting structure. Here, we examine the disordered packing of chains constructed out of flexibly connected hard spheres. Using x-ray tomography, we find that long chains pack into a low-density structure whose mechanical rigidity is mainly provided by the backbone. On compaction, randomly oriented, semi-rigid loops form along the chain, and the packing of chains can be understood as the jamming of these elements. Finally, we uncover close similarities between the packing of chains and the glass transition in polymers.

Zou, Ling-Nan; Cheng, Xiang; Rivers, Mark L.; Jaeger, Heinrich M.; Nagel, Sidney R.; UC

2009-12-01

205

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

206

Fluctuations, structure factor and polytetrahedra in random packings of sticky hard spheres  

E-print Network

Sequentially-built random sphere-packings have been numerically studied in the packing fraction interval $0.329 structure factors $S(Q)$ of the aggregates. Among various parameters (Voronoi tessellation, contact coordination number distribution,...), fluctuations were quantitatively evaluated by the direct evaluation of the fluctuations of the local sphere number density, which appears to follow a power law. The FWHM of the Voronoi cells volume shows a regular variation over the whole packing fraction range. Dirac peaks appear on the pair correlation function as the packing fraction of the aggregates decreases, indicating the growth of larger and larger polytetrahedra, which manifest in two ways on the structure factor, at low and large $Q$values. These low PF aggregates have a composite structure made of regular polytetrahedra embedded in a more disordered matrix. Incidentally, the irregularity index of the building tetrahedron appears as a better parameter than the packing fraction to describe various features of the aggregates structure.

Marc Bletry; Jean Bletry

2014-09-08

207

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

208

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

209

Theory of cylindrical dense packings of disks  

NASA Astrophysics Data System (ADS)

We have previously explored cylindrical packings of disks and their relation to sphere packings. Here we extend the analytical treatment of disk packings, analyzing the rules for phyllotactic indices of related structures and the variation of the density for line-slip structures, close to the symmetric ones. We show that rhombic structures, which are of a lower density, are always unstable, i.e., can be increased in density by small perturbations.

Mughal, A.; Weaire, D.

2014-04-01

210

Design of Intelligent Hydraulic Excavator Control System Based on PID Method  

Microsoft Academic Search

\\u000a Most of the domestic designed hydraulic excavators adopt the constant power design method and set 85%~90% of engine power\\u000a as the hydraulic system adoption power, it causes high energy loss due to mismatching of power between the engine and the\\u000a pump. While the variation of the rotational speed of engine could sense the power shift of the load, it provides

Jun Zhang; Shengjie Jiao; Xiaoming Liao; Penglong Yin; Yulin Wang; Kuimao Si; Yi Zhang; Hairong Gu

2009-01-01

211

Approximation Algorithms for Extensible Bin Packing  

E-print Network

In a variation of bin packing called extensible bin packing, the number of bins to use is specified as part of the input, and bins may be extended to hold more than the usual unit capacity. The cost of a bin is one if it is not extended, and the size if it is extended. The goal is to pack a set of items of given sizes with minimum cost. Adapting ideas in [6, 7, 3], we give a fully polynomial asymptotic approximation scheme for this extensible bin packing. We also show that the additive constant in the approximation bound cannot be eliminated unless P = NP .

E. G. Coffman, Jr.; George S. Lueker

212

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

213

Cocaine body packing in pregnancy.  

PubMed

Ingesting multiple packets of drugs ("body packing") is a well-described method of smuggling. Although older reports suggested that body packers were mostly young men, the demographics of this group may be changing because children, older patients, and pregnant women may be involved. Pregnant patients represent a challenge in management, particularly in the event of package rupture. Modification of standard management protocols, which were developed for nonpregnant body packers, may be necessary to address the anatomic and physiologic changes of pregnancy. We report the case of a pregnant cocaine body packer who required a perimortem cesarean section after the rupture of a cocaine packet. The care of the pregnant body packer is discussed. PMID:16934653

Cordero, Dwight R; Medina, Carlos; Helfgott, Andrew

2006-09-01

214

Simulation Model of Hydraulic Turbine Speed Control System and Its Parameters Identification Based on Resilient Adaptive Particle Swarm Optimization Algorithm  

Microsoft Academic Search

A new simulation model of hydraulic turbine speed control system and mathematical models of microcomputer governor is proposed, and to investigate the first and second regulation characteristics of hydraulic turbine speed control system, after hydraulic turbine group connected to the major power systems. Simulation model established and parameters were identified intelligently by using resilient adaptive particle swarm optimization algorithm. The

Bai Ji-zhong; Xie Ai-guo; Yu Xin-hua; Zhou Li-kun

2010-01-01

215

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

216

McDonald's Ecology Action Pack.  

ERIC Educational Resources Information Center

This ecology pack, designed for teacher use, focuses on the development of environmental awareness. The materials in the pack are designed to be used to introduce existig units of study, serve as a high interest supplement, or as a source of special projects. They are intended to stimulate thinking and activity that will carry beyond the school.

McDonald's Corp., Oak Brook, IL.

217

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

218

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

219

Mud pack therapy in rheumatoid arthritis  

Microsoft Academic Search

Summary Twenty-eight patients with classical or definite rheumatoid arthritis were randomly divided into two groups of fourteen patients each. All patients were treated once a day with mud packs derived from the Dead Sea heated to 40C and applied over the four extremities, neck and back for 20 minutes. Group 1 was treated with the true mud packs and Group

S. Sukenik; D. Buskila; L. Neumann; A. Kleiner-Baumgarten

1992-01-01

220

VripPack User's Guide Brian Curless  

E-print Network

and compiling vrip is fairly straightforward. VripPack depends on Tcl/Tk being installed and has been compiled most recently against Tcl/Tk version 8.4. VripPack comes with these libraries for Linux, but you may. The following web page is a good reference for installing Cygwin and Tcl/Tk as needed for vrip: http

Davis, James E.

221

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

222

Kid's PACK: Population Awareness Campaign Kit.  

ERIC Educational Resources Information Center

This fun and educational kit is designed specifically for elementary students. The "Kid's PACK" (Population Awareness Campaign Kit) entertains and informs children on the environment and human population growth through stories, games, and concrete ideas for making a difference. In three booklets, the "Kid's PACK" offers elementary students

Zero Population Growth, Inc., Washington, DC.

223

Circle packing immersions form regularly exhaustible surfaces  

Microsoft Academic Search

Circle packing imbeddings determine quasiconformai mappings which, in certain situations, approximate conformal mappings. In the more general case of circle packing immersions, it has not been proven that the associated immersion mappings are again quasiregular (i.e., of bounded dilatation but not necessarily univalent). If this were true, then their muitisheeted image surfaces would be regularly exhaustible and consequently Ahlfors' value

Kevin Callahan; Burt Rodin

1993-01-01

224

Microbial community analysis in biocathode microbial fuel cells packed with different materials  

PubMed Central

Biocathode MFCs using microorganisms as catalysts have important advantages in lowering cost and improving sustainability. Electrode materials and microbial synergy determines biocathode MFCs performance. In this study, four materials, granular activated carbon (GAC), granular semicoke (GS), granular graphite (GG) and carbon felt cube (CFC) were used as packed cathodic materials. The microbial composition on each material and its correlation with the electricity generation performance of MFCs were investigated. Results showed that different biocathode materials had an important effect on the type of microbial species in biocathode MFCs. The microbes belonging to Bacteroidetes and Proteobacteria were the dominant phyla in the four materials packed biocathode MFCs. Comamonas of Betaproteobacteria might play significant roles in electron transfer process of GAC, GS and CFC packed biocathode MFCs, while in GG packed MFC Acidovorax may be correlated with power generation. The biocathode materials also had influence on the microbial diversity and evenness, but the differences in them were not positively related to the power production. PMID:22458430

2012-01-01

225

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

226

COMPARACIN DE METODOLOGAS DE CLCULO DE PROPIEDADES HIDRULICAS DE UN SUELO A PARTIR DE DATOS MEDIDOS CON INFILTRMETRO DE DISCO Comparison of calculation methodologies of hydraulic properties of a soil from data measured with a disc infiltrometer  

Microsoft Academic Search

A B S T R A C T Tension disc infiltrometers are being increasingly used for determining in situ saturated and near-saturated soil hydraulic properties. The objective of this paper was to compare two calculation methodologies for different soil hydraulic properties starting from data measured with a disc tension infiltrometer. The experiment was carried out on packed soil in samples

Antonio M. Aoki; Roberto Sereno

227

Computer assisted sphere packing in higher dimensions  

SciTech Connect

A computer was used to help study the packing of equal spheres in dimension four and higher. A candidate for the densest packing in 4-space is described. The configuration of 24 spheres touching a central sphere in this packing is shown to be rigid, unlike the analogue in 3-space, in which the spheres can slide past each other. A system for interactively manipulating and visualizing such configurations is described. The Voronoi cell for a sphere is the set of points closer to its center than to any other sphere in the packing. The packing density is the ratio of a sphere's volume to the average of the volumes of the Voronoi cells. A method of constructing Voronoi cells and computing their volumes is presented, which works in any dimension. Examples of Voronoi cell volumes are given. 8 figs., 1 tab.

Max, N.

1991-01-01

228

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

229

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

230

Influence of nitrate, sulfate and operational parameters on the bioreduction of perchlorate using an up?flow packed bed reactor at high salinity  

Microsoft Academic Search

In this study we have investigated whether electron acceptors, such as nitrate or sulphate ions, competitively inhibit the reduction of perchlorate in brine in continuous up?flow packed bed bioreactors. The effect of pH and hydraulic retention time (HRT) on the reduction of perchlorate at high salinity has also been examined. Reduction of perchlorate was found to be only moderately influenced

J. Chung; S. Shin; J. Oh

2010-01-01

231

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

232

Packing of charged chains on toroidal geometries.  

PubMed

We study a strongly adsorbed flexible polyelectrolyte chain on tori. In this generalized Thomson problem, the patterns of the adsorbed chain are analyzed in the space of the toroidal coordinates and in terms of the orientation of each chain segment. Various patterns are found, including double spirals, disclination-like structures, Janus tori, and uniform wrappings, arising from the long-range electrostatic interaction and the toroidal geometry. Their broken mirror symmetry is quantitatively characterized by introducing an order parameter, an integral of the torsion. The uniform packing, which breaks the mirror symmetry the least, has the lowest value of the order parameter. In addition, it is found that the electrostatic energy of confined chains on tori conforms to a power law regardless of the screening effect in some typical cases studied. Furthermore, we study random walks on tori that generate chain configurations in the large screening limit or at large thermal fluctuation; some features associated with the toroidal geometry are discussed. PMID:23410352

Yao, Zhenwei; Olvera de la Cruz, Monica

2013-01-01

233

Monitoring Three-Dimensional Packings in Microgravity  

E-print Network

We present results from experiments with granular packings in three dimensions in microgravity as realized on parabolic flights. Two different techniques are employed to monitor the inside of the packings during compaction: (1) X-ray radiography is used to measure in transmission the integrated fluctuations of particle positions. (2) Stress-birefringence in three dimensions is applied to visualize the stresses inside the packing. The particle motions below the transition into an arrested packing are found to produce a well agitated state. At the transition, the particles lose their energy quite rapidly and form a stress network. With both methods, non-arrested particles (rattlers) can be identified. In particular, it is found that rattlers inside the arrested packing can be excited to appreciable dynamics by the rest-accelerations (g-jitter) during a parabolic flight without destroying the packings. At low rates of compaction, a regime of slow granular cooling is identified. The slow cooling extends over several seconds, is described well by a linear law, and terminates in a rapid final collapse of dynamics before complete arrest of the packing.

Peidong Yu; Stefan Frank-Richter; Alexander Borngen; Matthias Sperl

2013-12-21

234

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.

235

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

Leonard, Eric

236

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

237

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

238

Hydraulically actuated well shifting tool  

SciTech Connect

This patent describes a hydraulically actuated shifting tool for actuating a sliding member in a well tool. It comprises: a housing having a hydraulic fluid bore therein; shifting dog means positioned on the housing for movement away and toward the housing; locking dog means positioned on the housing for movement away and toward the body; shifting dog hydraulic actuating means in fluid communication with the bore for causing engagement of the shifting dogs with the sliding member; locking dog hydraulic actuating means in communication with the bore for causing engagement of the locking dogs with the locking means; and hydraulic shifting means in communication with the bore for causing relative movement between the shifting dog means and the locking dog means for shifting the sliding sleeve.

Roth, B.A.

1992-10-20

239

Structural properties of dense hard sphere packings.  

PubMed

We numerically study structural properties of mechanically stable packings of hard spheres (HS), in a wide range of packing fractions 0.53 ? ? ? 0.72. Detailed structural information is obtained from the analysis of orientational order parameters, which clearly reveals a disorder-order phase transition at the random close packing (RCP) density, ?c ? 0.64. Above ?c, the crystalline nuclei form 3D-like clusters, which upon further desification transform into alternating planar-like layers. We also find that particles with icosahedral symmetry survive only in a narrow density range in the vicinity of the RCP transition. PMID:25098389

Klumov, Boris A; Jin, Yuliang; Makse, Hernn A

2014-09-11

240

DEM simulation of experimental dense granular packing  

SciTech Connect

In this study we present numerical analysis performed on the experimental results of sphere packings of mono-sized hard sphere whose packing fraction spans across a wide range of 0.59<{Phi}<0.72. Using X-ray Computed Tomography (XCT), we have full access to the 3D structure of the granular packings. Numerical analysis performed on thr data provides the first experimental proofs of how densification affects local order parameters. Furthermore by combining Discrete Element Method (DEM) and the experimental results from XCT, we investigate how the intergranular forces change with the onset of crystallization.

Hanifpour, Maryam; Allaei, Mehdi Vaez [Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of); Francois, Nicolas; Saadatfar, Mohammad [Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University, Canberra (Australia)

2013-06-18

241

Improved Taxation Rate for Bin Packing Games  

NASA Astrophysics Data System (ADS)

A cooperative bin packing game is a N-person game, where the player set N consists of k bins of capacity 1 each and n items of sizes a 1, ? ,a n . The value of a coalition of players is defined to be the maximum total size of items in the coalition that can be packed into the bins of the coalition. We present an alternative proof for the non-emptiness of the 1/3-core for all bin packing games and show how to improve this bound ?= 1/3 (slightly). We conjecture that the true best possible value is ?= 1/7.

Kern, Walter; Qiu, Xian

242

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

243

Amazon flood wave hydraulics  

NASA Astrophysics Data System (ADS)

SummaryA bathymetric survey of 575 km of the central Amazon River and one of its tributaries, the Purus, are combined with gauged data to characterise the Amazon flood wave, and for hydraulic modelling of the main channel for the period June 1995-March 1997 with the LISFLOOD-FP and HEC-RAS hydraulic models. Our investigations show that the Amazon flood wave is subcritical and diffusive in character and, due to shallow bed slopes, backwater conditions control significant reach lengths and are present for low and high water states. Comparison of the different models shows that it is necessary to include at least the diffusion term in any model, and the RMSE error in predicted water elevation at all cross sections introduced by ignoring the acceleration and advection terms is of the order of 0.02-0.03 m. The use of a wide rectangular channel approximation introduces an error of 0.10-0.15 m on the predicted water levels. Reducing the bathymetry to a simple bed slope and with mean cross section only, introduces an error in the order of 0.5 m. These results show that when compared to the mean annual amplitude of the Amazon flood wave of 11-12 m, water levels are relatively insensitive to the bathymetry of the channel model. The implication for remote sensing studies of the central Amazon channel, such as those proposed with the Surface Water and Ocean Topography mission (SWOT), is that even relatively crude assumptions regarding the channel bathymetry will be valid in order to derive discharge from water surface slope of the main channel, as long as the mean channel area is approximately correct.

Trigg, Mark A.; Wilson, Matthew D.; Bates, Paul D.; Horritt, Matthew S.; Alsdorf, Douglas E.; Forsberg, Bruce R.; Vega, Maria C.

2009-07-01

244

Some Fundamental Mechanisms of Hydraulic Fracturing.  

E-print Network

??This dissertation focuses mainly on three topics: (1) mixed-mode branching and segmentation of hydraulic fractures in brittle materials, (2) hydraulic fracture propagation in particulate materials, (more)

Wu, Ruiting

2006-01-01

245

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

246

Beta dose distribution for randomly packed microspheres  

E-print Network

of radiation dose distribution when utilizing this technique. This study focuses on random packing of microspheres and seeks to determine dose distributions for specific cases. The Monte Carlo Neutral Particle code (MCNP) developed by Los Alamos National...

Urashkin, Alexander

2007-04-25

247

Induction Pack for students with health  

E-print Network

Induction Pack for students with health conditions, disabilities, or mental health issues - Accommodation - Disabled Students' Allowances - International Students - Enrolling at the University - Parking Team assist students with: · accessing and applying for additional funding such as the Disabled

Anderson, Jim

248

7 CFR 29.1048 - Packing.  

Code of Federal Regulations, 2010 CFR

...AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Standards Official Standard Grades for Flue-Cured Tobacco (u.s. Types 11, 12, 13, 14 and Foreign Type 92) 29.1048 Packing. A lot of tobacco...

2010-01-01

249

Universal structural characteristics of planar granular packs.  

PubMed

The dependence of structural self-organization of granular materials on preparation and grain parameters is key to predictive modeling. We study 60 different mechanically equilibrated polydisperse disc packs, generated numerically by two protocols. We show that, for same-variance disc size distributions (DSDs), (1) the mean coordination number of rattler-free packs versus the packing fraction is a function independent of initial conditions, friction, and the DSD, and (2) all quadron volume and cell order distributions collapse to universal forms, also independent of the above. This apparent universality suggests that, contrary to common wisdom, equilibrated granular structures may be determined mainly by the packing protocol and higher moments of the DSD. PMID:24655281

Matsushima, Takashi; Blumenfeld, Raphael

2014-03-01

250

Mechanical Characterization of Partially Crystallized Sphere Packings  

NASA Astrophysics Data System (ADS)

We study grain-scale mechanical and geometrical features of partially crystallized packings of frictional spheres, produced experimentally by a vibrational protocol. By combining x-ray computed tomography, 3D image analysis, and discrete element method simulations, we have access to the 3D structure of internal forces. We investigate how the network of mechanical contacts and intergranular forces change when the packing structure evolves from amorphous to near perfect crystalline arrangements. We compare the behavior of the geometrical neighbors (quasicontracts) of a grain to the evolution of the mechanical contacts. The mechanical coordination number Zm is a key parameter characterizing the crystallization onset. The high fluctuation level of Zm and of the force distribution in highly crystallized packings reveals that a geometrically ordered structure still possesses a highly random mechanical backbone similar to that of amorphous packings.

Hanifpour, M.; Francois, N.; Vaez Allaei, S. M.; Senden, T.; Saadatfar, M.

2014-10-01

251

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

252

Similarity of wet granular packing to gels.  

PubMed

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. PMID:25247441

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

2014-01-01

253

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

254

Mechanical characterization of partially crystallized sphere packings.  

PubMed

We study grain-scale mechanical and geometrical features of partially crystallized packings of frictional spheres, produced experimentally by a vibrational protocol. By combining x-ray computed tomography, 3D image analysis, and discrete element method simulations, we have access to the 3D structure of internal forces. We investigate how the network of mechanical contacts and intergranular forces change when the packing structure evolves from amorphous to near perfect crystalline arrangements. We compare the behavior of the geometrical neighbors (quasicontracts) of a grain to the evolution of the mechanical contacts. The mechanical coordination number Z_{m} is a key parameter characterizing the crystallization onset. The high fluctuation level of Z_{m} and of the force distribution in highly crystallized packings reveals that a geometrically ordered structure still possesses a highly random mechanical backbone similar to that of amorphous packings. PMID:25325661

Hanifpour, M; Francois, N; Vaez Allaei, S M; Senden, T; Saadatfar, M

2014-10-01

255

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

256

Finite Element Simulation of Dense Wire Packings  

E-print Network

A finite element program is presented to simulate the process of packing and coiling elastic wires in two- and three-dimensional confining cavities. The wire is represented by third order beam elements and embedded into a corotational formulation to capture the geometric nonlinearity resulting from large rotations and deformations. The hyperbolic equations of motion are integrated in time using two different integration methods from the Newmark family: an implicit iterative Newton-Raphson line search solver, and an explicit predictor-corrector scheme, both with adaptive time stepping. These two approaches reveal fundamentally different suitability for the problem of strongly self-interacting bodies found in densely packed cavities. Generalizing the spherical confinement symmetry investigated in recent studies, the packing of a wire in hard ellipsoidal cavities is simulated in the frictionless elastic limit. Evidence is given that packings in oblate spheroids and scalene ellipsoids are energetically preferred to spheres.

R. Vetter; F. K. Wittel; N. Stoop; H. J. Herrmann

2011-11-22

257

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2010 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices 890.5700 Cold pack. ...contour of the body and that provides cold therapy for body surfaces. (b)...

2010-04-01

258

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2011 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices 890.5700 Cold pack. ...contour of the body and that provides cold therapy for body surfaces. (b)...

2011-04-01

259

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2012 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices 890.5700 Cold pack. ...contour of the body and that provides cold therapy for body surfaces. (b)...

2012-04-01

260

21 CFR 890.5700 - Cold pack.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices 890.5700 Cold pack. ...contour of the body and that provides cold therapy for body surfaces. (b)...

2013-04-01

261

Packed capillary columns for liquid chromatography  

Microsoft Academic Search

SummaryFused silica capillaries, ? 130 ? 0.32mm have been packed with small reversed phase spherical silica particles, 3 or 2?m,\\u000a in order to achieve LC-systems giving high plate numbers at relatively low pressure drop in short analysis times. At optimal\\u000a conditions, columns packed with 3?m particles showed reduced plate heights, h, around 2.5, and the column flow resistance,\\u000a ?, was

S. Hoffmann; L. Blomberg

1987-01-01

262

Geometrical families of mechanically stable granular packings  

NASA Astrophysics Data System (ADS)

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 find that the dynamics is deterministic and highly contracting. That is, if the system is initialized in a MS packing at a given shear strain, it will quickly lock into a periodic orbit at subsequent shear strain, and therefore sample only a very small fraction of the possible MS packings in steady state. In studies with 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.

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

2009-12-01

263

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

264

Water hydraulics - A novel design of spool-type valves for enhanced dynamic performance  

Microsoft Academic Search

Hydraulic systems provide the most powerful actuators available. In the last decades however, their use in mechatronic systems has decreased, mainly because of two factors: the nature of the actuators themselves (such as noise, cleanliness, size) and the ease of use of electric systems. Water hydraulics, which use water instead of oil as working medium, have several advantages and could

Y. S. Yang; C. Semini; N. G. Tsagarakis; D. G. Caldwell; Yuquan Zhu

2008-01-01

265

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

266

Paper Number: 20.2 Direct Displacement Control of Hydraulic Actuators Based on  

E-print Network

Paper Number: 20.2 Direct Displacement Control of Hydraulic Actuators Based on a Self and Efficient Fluid Power University of Minnesota ABSTRACT Throttling loss of hydraulic systems is a major loss proportional valve. A hybrid nonlinear control strategy based on back-stepping technique and consideration

Li, Perry Y.

267

Effects of hydraulic pressure on the performance of single chamber air-cathode microbial fuel cells.  

PubMed

Scaling up of microbial fuel cells (MFCs) without losing power density requires a thorough understanding of the effect of hydraulic pressure on MFC performance. In this work, the performance of an activated carbon air-cathode MFC was evaluated under different hydraulic pressures. The MFC under 100 mmH2O hydraulic pressure produced a maximum power density of 1260 24 mW m(-2), while the power density decreased by 24.4% and 44.7% as the hydraulic pressure increased to 500 mmH2O and 2000 mmH2O, respectively. Notably, the performance of both the anode and the cathode had decreased under high hydraulic pressures. Electrochemical impedance spectroscopy tests of the cathode indicated that both charge transfer resistance and diffusion transfer resistance increased with the increase in hydraulic pressure. Denaturing gradient gel electrophoresis of PCR-amplified partial 16S rRNA genes demonstrated that the similarity among anodic biofilm communities under different hydraulic pressures was ? 90%, and the communities of all MFCs were dominated by Geobacter sp. These results suggested that the reduction in power output of the single chamber air-cathode MFC under high hydraulic pressures can be attributed to water flooding of the cathode and suppression the metabolism of anodic exoelectrogenic bacteria. PMID:24514078

Cheng, Shaoan; Liu, Weifeng; Guo, Jian; Sun, Dan; Pan, Bin; Ye, Yaoli; Ding, Weijun; Huang, Haobin; Li, Fujian

2014-06-15

268

Experimental Results of Pebble Beds Thermal Hydraulic Characteristics  

SciTech Connect

The purpose of this paper is to present the results of the experimental investigation of the thermal hydraulic characteristics for two types of test sections - thin annular pebble beds (i.e. spheres dumped in thin annular slots) and pebble beds placed between cylinders. The experimental results of heat transfer from the spheres and from a cylinder, as well as hydraulic drag for both types of test sections are presented in this paper. The results of performed experiments in the case of thin annular pebble beds demonstrated that maximum heat transfer and hydraulic drag is at the relative width of the annular slot K equal to 1.07 and 1.75 of spheres diameter. The heat transfer in internal layers at these values of K is equal to the heat transfer in the internal layers of large (unlimited) rhombic packing. The results of the experimental investigation of pebble beds between cylinders demonstrated that the randomly arranged pebble bed is preferable to the regular rhombic structure from the point of view of design simplicity, heat transfer from the cylinder and drag coefficient. (authors)

Rimkevicius, S.; Uspuras, E. [Lithuanian Energy Institute, 3 Breslaujos str., LT-44403 Kaunas (Lithuania)

2006-07-01

269

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

270

Packed Bed Combustion: An Overview  

E-print Network

in pulp and paper plants - trash incineration - power gen. (eg Denmark) - small scale district energy - CICS 2005 surface reduction oxidation primary air feed Ash products grate C + CO2 6 2CO C + 0.5 O2 6 CO of Ottawa - CICS 2005 Overfeed Char Bed - Operating Diagram 0 0.04 0.08 0.1 0 0.4 0.8 1 0 primary air mass

Hallett, William L.H.

271

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

2012-06-07

272

Circle Packings, Conformal Mappings, and Probability Edward Crane  

E-print Network

Circle Packings, Conformal Mappings, and Probability Edward Crane University of Bristol LMS packings Some open problems Edward Crane (Bristol) Circle Packings LMS Prospects in Mathematics Durham, 20 / 64 #12;Edward Crane (Bristol) Circle Packings LMS Prospects in Mathematics Durham, 20 / 64 #12;Maths

Wirosoetisno, Djoko

273

Hardness and Approximation Results for Packing Steiner Trees Joseph Cheriyan  

E-print Network

of approximation for several versions of the problem of packing Steiner trees. For packing edge-disjoint Steiner algorithms and hardness of approximation for several versions of the problem of packing Steiner trees. Given, are optional). The basic problem of packing edge-disjoint undirected Steiner trees is to #12;nd as many edge

Salavatipour, Mohammad R.

274

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:10 of transmissivity, hydraulic conductivity, or storativity in an aquifer system given measurements of hydraulic headEnsemble smoother assimilation of hydraulic head and return flow data to estimate hydraulic

Bau, Domenico A.

275

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

276

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

277

Pneumatic and Hydraulic Systems in Coal Fluidized Bed Combustor  

Microsoft Academic Search

Problem statement: This study designed the pneumatic and hydraulic systems in coal fluidized bed combustor. These are fluidization of silica sand bed material, Air distributor, centrifugal fan, electric motor power drive and surface heat exchanger. Approach: The effects of increased gas velocity on silica sand and the resultant drag force formed the basic equations in fluidization. Air distributor was introduced

I. A. Adetunde

278

First Fit bin packing: A tight analysis  

E-print Network

In the bin packing problem we are given an instance consisting of a sequence of items with sizes between 0 and 1. The objective is to pack these items into the smallest possible number of bins of unit size. FirstFit algorithm packs each item into the first bin where it fits, possibly opening a new bin if the item cannot fit into any currently open bin. In early seventies it was shown that the asymptotic approximation ratio of FirstFit bin packing is equal to 1.7. We prove that also the absolute approximation ratio for FirstFit bin packing is exactly 1.7. This means that if the optimum needs Opt bins, FirstFit always uses at most ?1.7 OPT? bins. Furthermore we show matching lower bounds for a majority of values of Opt, i.e., we give instances on which FirstFit uses exactly ?1.7 OPT ? bins. Such matching upper and lower bounds were previously known only for finitely many small values of OPT. The previous published bound on the absolute approximation ratio of FirstFit was 12/7 ? 1.7143. Recently a bound of 101/59 ? 1.7119 was claimed.

Gyrgy Dsa; Ji? Sgall

2013-01-01

279

2D packing using the Myriad framework  

NASA Astrophysics Data System (ADS)

Myriad is a framework for building networked and distributed vision systems and is described in a companion paper in this conference. Myriad allows the components of a multi-camera, multi-user vision system (web-cameras, image processing engines, intelligent device controllers, databases and the user interface terminals) to be interconnected and operated together, even if they are physically separated by many hundreds, or thousands, of kilometres. This is achieved by operating them as Internet services. The principal objective in this article is to illustrate the simplicity of harmonising visual control with an existing system using Myriad. However, packing of 2-dimensional blob-like objects is of considerable commercial importance in some industries and involves robotic handling and/or cutting. The shapes to be packed may be cut from sheet metal, glass, cloth, leather, wood, card, paper, composite board, or flat food materials. In addition, many 3D packing applications can realistically be tackled only by regarding them as multi-layer 2D applications. Using Myriad to perform 2D packing, a set of blob-like input objects ("shapes") can be digitised using a standard camera (e.g. a "webcam"). The resulting digital images are then analysed, using a separate processing engine, perhaps located on a different continent. The packing is planned by another processing system, perhaps on a third continent. Finally, the assembly is performed using a robot, usually but not necessarily, located close to the camera.

Chatburn, Luke T.; Batchelor, Bruce G.

2004-02-01

280

Review and assessment of factors affecting hydraulic conductivity values determined from slug tests. Final report  

SciTech Connect

The purpose of the study was to evaluate factors that influence hydraulic conductivity values determined by slug tests in typical monitoring wells. Procedures for conducting tests and methods for analyzing test results are summarized and compared. Sensitivity analyses were conducted to identify and evaluate the factors influencing the calculated hydraulic conductivity values for available slug test solutions. These factors include mathematical approximation of the shape of the screen intake, the presence of a less or more permeable well skin, determination of the radius of influence, formation anisotropies and heterogeneities, partial penetration and boundary conditions, and filter sand pack drainage from wells with screens that span the water table (partially submerged well screens). A method is presented to calculate the filter sand's specific yield from hydraulic head versus time curves for incorporation into existing slug test solutions.

Binkhorst, G.K.; Robbins, G.A.

1994-02-01

281

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

282

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

283

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

284

Safety considerations for fabricating lithium battery packs  

NASA Technical Reports Server (NTRS)

Lithium cell safety is a major issue with both manufacturers and end users. Most manufacturers have taken great strides to develop the safest cells possible while still maintaining performance characteristics. The combining of lithium cells for higher voltages, currents, and capacities requires the fabricator of lithium battery packs to be knowledgable about the specific electrochemical system being used. Relatively high rate, spirally wound (large surface area) sulfur oxychloride cells systems, such as Li/Thionyl or Sulfuryl chloride are considered. Prior to the start of a design of a battery pack, a review of the characterization studies for the cells should be conducted. The approach for fabricating a battery pack might vary with cell size.

Ciesla, J. J.

1986-01-01

285

Kinase packing defects as drug targets  

PubMed Central

Protein packing defects constitute structural singularities arising from backbone overexposure to water. Such features may be targeted in kinase-inhibitor design to achieve specificity, to control cross reactivity and to overcome drug resistant mutations. Protein kinases constitute major targets in molecular cancer therapy. The structural conservation of kinases causes specificity problems in most drug inhibitors, often resulting in dangerous side effects. Here we survey recent approaches in drug design that exploit a molecular marker for specificity: the pattern of packing defects. These packing defects are solvent-exposed intramolecular hydrogen bonds that may be protected by drugs upon association. In this light, we review design strategies to achieve paralog discrimination, to control cross reactivity and to overcome drug resistance induced by target mutations. Introduction PMID:17993409

Crespo, Alejandro; Fernandez, Ariel

2007-01-01

286

The Centre for PTMC provides an industrial focus for training, consultancy and research in power transmission and motion  

E-print Network

The Centre for PTMC provides an industrial focus for training, consultancy and research in power of Continuing Professional Development (CPD) courses is offered: Introduction to Hydraulic Circuits and Components Component Selection for Hydraulic Systems Simulation of Hydraulic Systems Control

Burton, Geoffrey R.

287

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

288

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

289

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

290

Correlation between Voronoi volumes in disc packings  

E-print Network

We measure the two-point correlation of free Voronoi volumes in binary disc packings, where the packing fraction $\\phi_{\\rm avg}$ ranges from 0.8175 to 0.8380. We observe short-ranged correlations over the whole range of $\\phi_{\\rm avg}$ and anti-correlations for $\\phi_{\\rm avg}>0.8277$. The spatial extent of the anti-correlation increases with $\\phi_{\\rm avg}$ while the position of the maximum of the anti-correlation and the extent of the positive correlation shrink with $\\phi_{\\rm avg}$. We conjecture that the onset of anti-correlation corresponds to dilatancy onset in this system.

Song-Chuan Zhao; Stacy Sidle; Harry L. Swinney; Matthias Schrter

2011-09-05

291

Modelling liquid redistribution in a packed bed  

NASA Astrophysics Data System (ADS)

The paper is devoted to the computational fluid dynamics (CFD) simulation of liquid spreading process in a packed bed. The volume of fluid (VOF) approach was applied to simulate the flow in a realistic porous region composed of 6mm Raschig rings. Modelling results were used to determine the probability density function (PDF) distribution of liquid velocity vector orientation angle which was then implemented into 2-fluid Euler-Euler multiphase model of packing column. The simulation showed that the model is capable to simulate adequately the liquid redistribution in a porous region being, however, much more efficient computationally than the VOF method.

Niegodajew, Pawe?; Asendrych, Dariusz; Marek, Maciej; Drobniak, Stanis?aw

2014-08-01

292

On Variable-Sized Bin Packing  

E-print Network

In variable sized bin packing, a number of bin types are given and the goal is to pack a list of items by choosing appropriate bins such that the total size of bins used is minimized. In this paper, we present absolute worst-case analysis for on-line algorithms. Then we consider an related problem: how to design k different bin sizes such that for any item list the waste space of bins used is minimized. A best possible off-line algorithm is showed for arbitrary k and a best possible on-line algorithm is derived for any fixed number k.

Guochuan Zhang

293

Finding bridges in packings of colloidal spheres  

E-print Network

We identify putative load-bearing structures (bridges) in experimental colloidal systems studied by confocal microscopy. Bridges are co-operative structures that have been used to explain stability and inhomogeneous force transmission in simulated granular packings with a range of densities. We show that bridges similar to those found in granular simulations are present in real experimental colloidal packings. We describe critically the bridge-finding procedure for real experimental data and propose a new criterion-Lowest Mean Squared Separation (LSQS)-for selecting optimum stabilisations.

Matthew C. Jenkins; Mark D. Haw; Gary C. Barker; Wilson C. K. Poon; Stefan U. Egelhaaf

2010-06-17

294

THE THREE DIMENSIONAL THERMAL HYDRAULIC CODE BAGIRA.  

SciTech Connect

BAGIRA - a thermal-hydraulic program complex was primarily developed for using it in nuclear power plant simulator models, but is also used as a best-estimate analytical tool for modeling two-phase mixture flows. The code models allow consideration of phase transients and the treatment of the hydrodynamic behavior of boiling and pressurized water reactor circuits. It provides the capability to explicitly model three-dimensional flow regimes in various regions of the primary and secondary circuits such as, the mixing regions, circular downcomer, pressurizer, reactor core, main primary loops, the steam generators, the separator-reheaters. In addition, it is coupled to a severe-accident module allowing the analysis of core degradation and fuel damage behavior. Section II will present the theoretical basis for development and selected results are presented in Section III. The primary use for the code complex is to realistically model reactor core behavior in power plant simulators providing enhanced training tools for plant operators.

KALINICHENKO,S.D.; KOHUT,P.; KROSHILIN,A.E.; KROSHILIN,V.E.; SMIRNOV,A.V.

2003-05-04

295

1. 1. In this class, the two of us will teach you about hydraulics.  

E-print Network

; and design dams, weirs, hydraulic power plants, and so on. 10. 10. In coastal engineering, we can calculate such as pressure, temperature, and salinity. 7. 7. Compressibility is the deformation characteristics of a fluid

Takahashi, Ryo

296

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

...SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power 1926.305 Jackslever and ratchet, screw, and hydraulic. (a) General requirements. (1)...

2014-07-01

297

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

298

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

299

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

300

Fluid shear influences on the performance of hydraulic flocculation systems.  

PubMed

Gravity driven hydraulic flocculators that operate in the absence of reliable electric power are better suited to meet the water treatment needs of green communities, resource-poor communities, and developing countries than conventional mechanical flocculators. However, current understanding regarding the proper design and operation of hydraulic flocculation systems is insufficient. Of particular interest is the optimal fluid shear level needed to produce low turbidity water. A hydraulic tube flocculator was used to study how fluid shear levels affect the settling properties of a flocculated alum-kaolin suspension. A Flocculation Residual Turbidity Analyzer (FReTA) was used to quantitatively compare the sedimentation velocity distributions and the post-sedimentation residual turbidities of the flocculated suspensions to see how they were affected by varying fluid shear, G, and hydraulic residence time, ?, while holding collision potential, G?, constant. Results show that floc breakup occurred at all velocity gradients evaluated. High floc settling velocities were correlated with low residual turbidities, both of which were optimized at low fluid shear levels and long fluid residence times. This study shows that, for hydraulic flocculation systems under the conditions described in this paper, low turbidity water is produced when fluid shear is kept at a minimum. Use of the product G? for design of laminar flow tube flocculators is insufficient if residual turbidity is used as the metric for performance. At any G? within the range tested in this study, best performance is obtained when G is small and ? is long. PMID:21880341

Tse, Ian C; Swetland, Karen; Weber-Shirk, Monroe L; Lion, Leonard W

2011-11-01

301

78 FR 4092 - Airworthiness Directives; Cessna Aircraft Company Airplanes  

Federal Register 2010, 2011, 2012, 2013

...inspect the aircraft's hydraulic power pack wiring for incorrect installation...FOR FURTHER INFORMATION CONTACT: Richard Rejniak, Aerospace Engineer, Wichita...inspect the aircraft's hydraulic power pack wiring for incorrect...

2013-01-18

302

7 CFR 51.2338 - Standard pack.  

Code of Federal Regulations, 2011 CFR

... (1) Fruit packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end. (f) In order...

2011-01-01

303

7 CFR 51.3152 - Standard pack.  

Code of Federal Regulations, 2011 CFR

...Nectarines packed in containers equipped with cell compartments, cardboard fillers or molded trays shall be of the proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end of the fruit....

2011-01-01

304

7 CFR 51.2338 - Standard pack.  

Code of Federal Regulations, 2010 CFR

... (1) Fruit packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end. (f) In order...

2010-01-01

305

7 CFR 51.3152 - Standard pack.  

Code of Federal Regulations, 2013 CFR

...Nectarines packed in containers equipped with cell compartments, cardboard fillers or molded trays shall be of the proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end of the fruit....

2013-01-01

306

7 CFR 51.2338 - Standard pack.  

Code of Federal Regulations, 2012 CFR

... (1) Fruit packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end. (f) In order...

2012-01-01

307

7 CFR 51.3152 - Standard pack.  

...Nectarines packed in containers equipped with cell compartments, cardboard fillers or molded trays shall be of the proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end of the fruit....

2014-01-01

308

7 CFR 51.3152 - Standard pack.  

Code of Federal Regulations, 2012 CFR

...Nectarines packed in containers equipped with cell compartments, cardboard fillers or molded trays shall be of the proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end of the fruit....

2012-01-01

309

7 CFR 51.2338 - Standard pack.  

Code of Federal Regulations, 2013 CFR

... (1) Fruit packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end. (f) In order...

2013-01-01

310

7 CFR 51.3152 - Standard pack.  

Code of Federal Regulations, 2010 CFR

...Nectarines packed in containers equipped with cell compartments, cardboard fillers or molded trays shall be of the proper size for the cells, fillers, or molds in which they are...measured at right angles to a line from stem to blossom end of the fruit....

2010-01-01

311

Sheffield Students' Union Freshers'Media Pack  

E-print Network

Quarter page, 170 x 131 mm: £200 DIGITAL MEDIA Advertise with us online and target students 24 hours a daySheffield Students' Union Freshers'Media Pack With around 8,000 new students heading to Sheffield this year will be even bigger! Premium stall (Including sponsorship): £1200 + (Dependent on level

Li, Yi

312

Sheffield Students' Union Freshers' Media Pack 2013  

E-print Network

Quarter page, 170 x 131 mm: £200 DIGITAL MEDIA Advertise with us online and target students 24 hours a daySheffield Students' Union Freshers' Media Pack 2013 With around 8,000 new students heading (Including logo on publicity): £1200 + (Dependent on level of sponsoship) Gold (Front of the Octagon): £1000

Oakley, Jeremy

313

Porous bead packings for gas chromatography  

NASA Technical Reports Server (NTRS)

Porous polyaromatic packing beads have low polarity, high efficiency, short retention time, and may be synthesized in size range of 50 to 150 micrometers (100 to 270 mesh). Mechanically strong beads may be produced using various materials depending on elements and compounds to be identified.

Pollock, G. E.; Woeller, F. H.

1979-01-01

314

Packing Costas Arrays J.H. Dinitz  

E-print Network

Packing Costas Arrays J.H. Dinitz Department of Mathematics and Statistics University of Vermont. Cheriton School of Computer Science University of Waterloo Waterloo Ontario, N2L 3G1, Canada February 4, 2011 Dedicated to Ralph Stanton Abstract A Costas latin square of order n is a set of n disjoint Costas

Stinson, Douglas

315

Hear Your Heart 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

316

Contact forces in a granular packing  

Microsoft Academic Search

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

Farhang Radjai; Stphane Roux; Jean Jacques Moreau

1999-01-01

317

Comparison of some bin packing heuristics  

E-print Network

of an approximation algorithm involve worst case and average case analyses. A well known problem in the field of approximation algorithms is a bin packing problem : given a list of sizes in the range (0,1] and an unlimited number of bins of size 1, find an assignment...

Blach, Beata Bozena

2012-06-07

318

7 CFR 51.1217 - Standard pack.  

Code of Federal Regulations, 2010 CFR

...packages shall be well filled and tightly packed but the contents shall not show excessive or unnecessary bruising because of overfilled packages. The number of peaches in the box shall not vary more than 4 from the number indicated on the box. (d)...

2010-01-01

319

That Magnetic Dog 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

2010-04-24

320

Random lasing in closely packed resonant scatterers  

Microsoft Academic Search

We report experimental and theoretical studies of the random lasing threshold and its fluctuation in an ensemble of highly packed spherical dielectric scatterers. The ratio of the sphere diameter to the lasing wavelength was varied in a wide range, which covered the transition from the weak Rayleigh scattering regime to the strong Mie scattering regime. Experimentally, when the diameters of

Xiaohua H. Wu; Alexey Yamilov; Heeso Noh; Hui Cao; Eric W. Seelig; Robert P. H. Chang

2004-01-01

321

Stuffed Derivatives of Close-Packed Structures  

ERIC Educational Resources Information Center

Decades ago Buerger described and later Palmer reviewed stuffed silica crystal structures widely used by mineralogists. Many publications and books have discussed common crystal structures in terms of close-packing of one set of atoms or ions (P sites) with other atoms or ions in tetrahedral (T) or octahedral (O) sites. Douglas and Ho described

Douglas, Bodie E.

2007-01-01

322

PROTEIN RECOVERY FROM BEEF PACKING EFFLUENT  

EPA Science Inventory

The wastewater from a beef packing plant contained 4,600 mg/1 COD and 2,500 mg/1 of suspended solids. A physiochemical wastewater treatment process that recovers protein removed 80% of the oxygen demand and suspended solids, and 94% of the fat, oil, and grease. Total cost was $3 ...

323

Packing frustration in dense confined fluids.  

PubMed

Packing frustration for confined fluids, i.e., the incompatibility between the preferred packing of the fluid particles and the packing constraints imposed by the confining surfaces, is studied for a dense hard-sphere fluid confined between planar hard surfaces at short separations. The detailed mechanism for the frustration is investigated via an analysis of the anisotropic pair distributions of the confined fluid, as obtained from integral equation theory for inhomogeneous fluids at pair correlation level within the anisotropic Percus-Yevick approximation. By examining the mean forces that arise from interparticle collisions around the periphery of each particle in the slit, we calculate the principal components of the mean force for the density profile - each component being the sum of collisional forces on a particle's hemisphere facing either surface. The variations of these components with the slit width give rise to rather intricate changes in the layer structure between the surfaces, but, as shown in this paper, the basis of these variations can be easily understood qualitatively and often also semi-quantitatively. It is found that the ordering of the fluid is in essence governed locally by the packing constraints at each single solid-fluid interface. A simple superposition of forces due to the presence of each surface gives surprisingly good estimates of the density profiles, but there remain nontrivial confinement effects that cannot be explained by superposition, most notably the magnitude of the excess adsorption of particles in the slit relative to bulk. PMID:25194375

Nygrd, Kim; Sarman, Sten; Kjellander, Roland

2014-09-01

324

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Hydraulic, pneumatic, or photoelectric plethysmographs...Devices 870.2780 Hydraulic, pneumatic, or photoelectric plethysmographs...Identification. A hydraulic, pneumatic, or photoelectric...

2012-04-01

325

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

...2014-04-01 false Hydraulic, pneumatic, or photoelectric plethysmographs...Devices 870.2780 Hydraulic, pneumatic, or photoelectric plethysmographs...Identification. A hydraulic, pneumatic, or photoelectric...

2014-04-01

326

Hydraulic charcterization of carbonatic rock  

NASA Astrophysics Data System (ADS)

The hydraulic conductivity, K(?), and the water retention, ?(h), are needed to predict the flow of water and solute transport in unsaturated porous media. During recent decades methods have been developed to determine these hydraulic properties for rock. We have developed a methodology, based on Wind's evaporation method for soils, to measure in the laboratory the water retention and hydraulic conductivity in coherent porous rock. This methodology requires matric potential and water content estimation at three depths of the rock sample during a transient evaporation process. We applied this methodology to calcarenite, a sedimentary carbonate rock of marine environment. Little compacted, with a granular skeleton constituted by equal quantities of lithoclasts and bioclasts soaked in a matrix, this rock is widely represented in the Mediterranean basin, and often constitutes a thick layer of the vadose zone. Samples of three different lithotypes of calcarenites have been used for the tests: two of them (lithotypes A and B) came from the same place but different depths and the third lithotype, M, from an outcrop in another area. The water retention curves show similar values near saturation, indicating similar total porosity for the different lithotypes. For matric potential below -20 cm the curves differ; at the same matric potential the water content of lithotype M exceeds that of lithotypes A and B; moreover, at higher matric potential the curve of M shows smaller slope than those of A and B. Therefore M has a greater water retention capacity and spread of pore-size distribution. The results for hydraulic conductivity show greater values for A and B than for M over the entire range of matric potential investigated, though at high water content the differences are small. Therefore the hydraulic behaviour of the analysed rocks is very similar near the saturation while it differs in unsaturated conditions. These considerations point out the need of accurate studies on unsaturated hydraulic behaviour of carbonatic rocks.

Caputo, M. C.; Basile, A.; de Mascellis, R.; Nimmo, J. R.; Vurro, M.; Walsh, N.

2003-04-01

327

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

328

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

329

Inverse modeling of hydraulic tests in fractured crystalline rock based on a transition probability geostatistical approach  

NASA Astrophysics Data System (ADS)

This paper presents numerical simulations of a series of hydraulic interference tests conducted in crystalline bedrock at Olkiluoto (Finland), a potential site for the disposal of the Finnish high-level nuclear waste. The tests are in a block of crystalline bedrock of about 0.03 km3 that contains low-transmissivity fractures. Fracture density, orientation, and fracture transmissivity are estimated from Posiva Flow Log (PFL) measurements in boreholes drilled in the rock block. On the basis of those data, a geostatistical approach relying on a transitional probability and Markov chain models is used to define a conceptual model based on stochastic fractured rock facies. Four facies are defined, from sparsely fractured bedrock to highly fractured bedrock. Using this conceptual model, three-dimensional groundwater flow is then simulated to reproduce interference pumping tests in either open or packed-off boreholes. Hydraulic conductivities of the fracture facies are estimated through automatic calibration using either hydraulic heads or both hydraulic heads and PFL flow rates as targets for calibration. The latter option produces a narrower confidence interval for the calibrated hydraulic conductivities, therefore reducing the associated uncertainty and demonstrating the usefulness of the measured PFL flow rates. Furthermore, the stochastic facies conceptual model is a suitable alternative to discrete fracture network models to simulate fluid flow in fractured geological media.

Blessent, Daniela; Therrien, Ren; Lemieux, Jean-Michel

2011-12-01

330

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

331

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.

332

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.

333

THERMAL HYDRAULICS KEYWORDS: neutron activation,  

E-print Network

as a neutron source, and the detection of the induced 16 N activity in the flow was performed by two bismuth portable is the pulsed-neutron activation ~PNA! method. This method is based on the detection of radiationTHERMAL HYDRAULICS KEYWORDS: neutron activation, flow measurements, evaluation methods FLOWACT

Pázsit, Imre

334

Hydraulic drive for control rods  

Microsoft Academic Search

A nuclear reactor is disclosed wherein hydraulic drive mechanisms for control rods are provided with a positive mechanical latching arrangement to maintain the control rods in a withdrawn position with respect to the core. With this arrangement, the coil of an associated electromagnet must be deliberately energized in order to insert the control rod into the core thus making accidental

E. Frisch; H. N. Andrews

1976-01-01

335

DC\\/DC Converters Design and Control for Hybrid Power System  

Microsoft Academic Search

This paper presents ultracapacitor and battery pack modeling with a DC\\/DC converter in a hybrid power system. Ultracapacitor is dimensioned for peak power requirement and battery pack provides the power in steady state. A Topology structure was analyzed that the ultracapacitor system is connected with battery pack parallel after a bidirectional DC\\/DC converter. A detailed theoretical analysis on the control

He Hongwen; Xiong Rui

2010-01-01

336

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

337

27 CFR 24.308 - Bottled or packed wine record.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Bottled or packed wine record. 24.308 Section 24.308 ...BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Records and Reports 24.308 Bottled or packed wine record. A proprietor who bottles,...

2010-04-01

338

27 CFR 24.255 - Bottling or packing wine.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Bottling or packing wine. 24.255 Section 24.255 Alcohol...BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Storage, Treatment and Finishing of Wine Bottling, Packing, and Labeling of Wine...

2010-04-01

339

Energy Saving in Distillation Using Structured Packing and Vapor Recompression  

E-print Network

"Distillation is a big consumer of energy in process plant operations. A first step to energy cost savings is the use of high efficiency structured packing in place of trays or dumped packings in conventionally operated distillation columns. Larger...

Hill, J.H.

340

Interstitial-Scale Modeling of Packed-Bed Reactors.  

E-print Network

??Packed-beds are common to adsorption scrubbers, packed bed reactors, and trickle-bed reactors widely used across the petroleum, petrochemical, and chemical industries. The micro structure of (more)

Combest, Daniel Parks

2012-01-01

341

11. Boiler building at west end of Packing house adjacent ...  

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

11. Boiler building at west end of Packing house adjacent to railroad tracks, looking east, northeast. - College Heights Lemon Packing House, 519-532 West First Street, Claremont, Los Angeles County, CA

342

7 CFR 51.2840 - Export packing requirements.  

Code of Federal Regulations, 2010 CFR

...OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Onions (Other Than Bermuda-Granex-Grano and Creole Types) Export Packing Requirements 51.2840 Export packing requirements....

2010-01-01

343

7 CFR 51.2840 - Export packing requirements.  

Code of Federal Regulations, 2011 CFR

...OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Onions (Other Than Bermuda-Granex-Grano and Creole Types) Export Packing Requirements 51.2840 Export packing requirements....

2011-01-01

344

Hydraulic characterization of " Furcraea andina  

NASA Astrophysics Data System (ADS)

The present level of pollution, increasingly involving groundwaters, constitutes a serious risk for environment and human health. Therefore the remediation of saturated and unsaturated soils, removing pollutant materials through innovative and economic bio-remediation techniques is more frequently required. Recent studies on natural fiber development have shown the effectiveness of these fibers for removal of some heavy metals, due to the lignin content in the natural fibers which plays an important role in the adsorption of metal cations (Lee et al., 2004; Troisi et al., 2008; C. Fallico, 2010). In the context of remediation techniques for unsaturated and/or saturated zone, an experimental approach for the hydraulic characterization of the "Furcraea andina" (i.e., Cabuya Blanca) fiber was carried out. This fiber is native to Andean regions and grows easily in wild or cultivated form in the valleys and hillsides of Colombia, Ecuador, and Peru. Fibers of "Furcraea andina" were characterized by experimental tests to determine their hydraulic conductivity or permeability and porosity in order to use this medium for bioremediation of contaminated aquifer exploiting the physical, chemical and microbial capacity of natural fiber in heavy metal adsorption. To evaluate empirically the hydraulic conductivity, laboratory tests were carried out at constant head specifically on the fibers manually extracted. For these tests we used a flow cell (used as permeameter), containing the "Furcraea andina" fibers to be characterized, suitably connected by a tygon pipe to a Marriott's bottle, which had a plastic tube that allow the adjustment of the hydraulic head for different tests to a constant value. By this experiment it was also possible to identify relationships that enable the estimation of permeability as a function of density, i.e. of the compaction degree of the fibers. Our study was carried out for three values of hydraulic head (H), namely 10, 18, and 25 cm and for each constant head we repeated the test for three different rate of fiber compaction within the flow cell, corresponding to three different densities (146 kg/m3, 200 kg/m3 and 240 kg/m3). We observed that with increasing density of the fibers there is an increase of hydraulic conductivity. The importance of the experimental results on permeability acquires greater relevance when compared to the values of hydraulic conductivity already known from the literature for different soils types. In this study, special attention has been given to the value of hydraulic conductivity of this fiber, considering that in the framework of groundwater remediation strategies if the hydraulic conductivity in the barrier is lower than that of the surrounding aquifer, the plume may change its natural pathway, bypassing the barrier and veering towards larger hydraulic conductivity. Reference Lee, B. G. and Rowell, R. M.: Removal of heavy metal ions from aqueous solutions using lignocellulosic fibers, J. Natural Fibers, 1, 97-108, 2004. Troisi, S., Fallico, C., Straface, S., and Mazzuca, L.: Biodreni per la bonifica di siti contaminati realizzati con fibre naturali liberiane ad elevato sviluppo superficiale. Brevetto dell'Universit della Calabria (n.: CS2008A00018), 2008. C. Fallico, S. Troisi, A. Molinari, and M. F. Rivera.: Characterization of broom fibers for PRB in the remediation of aquifers contaminated by heavy metals, Biogeosciences journal , 7, 2545-2556, 2010

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

2012-04-01

345

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

346

An alternative cooling system to enhance the safety of Li-ion battery packs  

Microsoft Academic Search

A passive thermal management system is evaluated for high-power Li-ion packs under stressful or abusive conditions, and compared with a purely air-cooling mode under normal and abuse conditions. A compact and properly designed passive thermal management system utilizing phase change material (PCM) provides faster heat dissipation than active cooling during high pulse power discharges while preserving sufficiently uniform cell temperature

Riza Kizilel; Rami Sabbah; J. Robert Selman; Said Al-Hallaj

2009-01-01

347

23 CFR 650.111 - Location hydraulic studies.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Location hydraulic studies. 650.111 Section 650...STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains 650.111 Location hydraulic studies. (a) National...

2010-04-01

348

Hydraulically actuated fuel injector including a pilot operated spool valve assembly and hydraulic system using same  

Microsoft Academic Search

The present invention relates to hydraulic systems including hydraulically actuated fuel injectors that have a pilot operated spool valve assembly. One class of hydraulically actuated fuel injectors includes a solenoid driven pilot valve that controls the initiation of the injection event. However, during cold start conditions, hydraulic fluid, typically engine lubricating oil, is particularly viscous and is often difficult to

Scott F

2002-01-01

349

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

350

Electro-Hydraulic Proportional Synchronous Control System of Ring Gate for Hydraulic Turbine  

Microsoft Academic Search

Based on the analysis of opening and closing control manner for ring gate of hydraulic turbine, the electro-hydraulic proportional control system for ring gate of hydraulic turbine was studied. A new control system, which combines mechanics, hydraulics and electrics, was presented. More particularly, the modules of speed control and multi-cylinder synchronous control for the movement of ring gate was designed.

Juliang Xiao; Guodong Wang; Weike Song

2009-01-01

351

Flow through packed bed reactors: 1. Single-phase flow  

Microsoft Academic Search

Single-phase pressure drop was studied in a region of flow rates that is of particular interest to trickle bed reactors (10Re?*500). Bed packings were made of uniformly sized spherical and non-spherical particles (cylinders, rings, trilobes, and quadralobes). Particles were packed by means of two methods: random close or dense packing (RCP) and random loose packing (RLP) obtaining bed porosities in

Damjan Nemec; Janez Levec

2005-01-01

352

Land Use Effects on Soil Hydraulic Properties  

Microsoft Academic Search

Tillage alters the pore structure and hydraulic properties of soils. Likewise, reestablishment of grass on cropland will, over time, produce changes in soil hydraulic properties that can influence the amount of plant available water. We conducted a study to characterize and compare soil hydraulic properties on adjacent native grassland, cropland, and Conservation Reserve Program (CRP) sites at three locations in

R. C. Schwartz; P. W. Unger; S. R. Evett

353

May 10, 2013 Determining Soil Hydraulic Conductivity  

E-print Network

May 10, 2013 Determining Soil Hydraulic Conductivity from Cosmic-ray Neutron Data Adam M Current methods used to quantify hydraulic conductivity require either lab testing of soil samples trends of the COSMOS soil moisture signal, it may be possible to estimate area averaged soil hydraulic

Fay, Noah

354

4, 37193769, 2007 A model for hydraulic  

E-print Network

HESSD 4, 3719­3769, 2007 A model for hydraulic redistribution G. G. Amenu and P. Kumar Title Page are under open-access review for the journal Hydrology and Earth System Sciences A model for hydraulic;HESSD 4, 3719­3769, 2007 A model for hydraulic redistribution G. G. Amenu and P. Kumar Title Page

Paris-Sud XI, Université de

355

Hydraulic Geometry: Empirical Investigations and Theoretical Approaches  

E-print Network

Hydraulic Geometry: Empirical Investigations and Theoretical Approaches B.C. Eatona, a Department of Geography, The University of British Columbia 1984 West Mall, Vancouver, BC, V6T 1Z2 Abstract Hydraulic. One approach to hydraulic geometry considers temporal changes at a single location due to variations

Eaton, Brett

356

Hydraulic conductivity tests on compacted clay  

Microsoft Academic Search

Permeability tests were performed in the laboratory on compacted clay to study the effects of type of permeameter, hydraulic anisotropy, diameter of test specimens, storage time, and desiccation cracking. Essentially identical hydraulic conductivities were measured with compaction-mold, consolidationcell, and flexible-wall permeameters. With good bonding between lifts, hydraulic conductivity was isotropic. Test specimens having a diameter of 15 cm were twice

Stephen S. Boynton; David E. Daniel

1985-01-01

357

LA-12968-MS The Unsaturated Hydraulic  

E-print Network

LA-12968-MS The Unsaturated Hydraulic Characteristics of the BandelierTuff LosN A T I O N A L L A B technical correctness. #12;The Unsaturated Hydraulic Characteristics of the Bandelier Tuff David B. Rogers........................................................................................................4 Hydraulic Data Presentation

358

Numerical Study of a Turbulent Hydraulic Jump  

E-print Network

Numerical Study of a Turbulent Hydraulic Jump Qun Zhao, Shubhra Misra, Ib. A. Svendsen and James T of a Turbulent Hydraulic Jump ­ p.1/14 #12;Objective Our ultimate goal is to study the breaking waves. Numerical Study of a Turbulent Hydraulic Jump ­ p.2/14 #12;A moving bore Qiantang Bore China (Courtesy of Dr J

Zhao, Qun

359

Hydraulic Cooling Tower Driver- The Innovation  

E-print Network

-drive eliminates these items from the drive train and puts the same electric motor HP at ground level close coupled to a hydraulic pump, filters, and oil reservoir. Hydraulic lines bring oil pressure to the hydraulic motor, which is more than 75% less weight than...

Dickerson, J. A.

360

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

361

Hydraulic Fracture: multiscale processes and moving  

E-print Network

Hydraulic Fracture: multiscale processes and moving interfaces Anthony Peirce Department Siebrits (SLB, Houston) #12;2 Outline · What is a hydraulic fracture? · Mathematical models of hydraulic fracture · Scaling and special solutions for 1-2D models · Numerical modeling for 2-3D problems

Peirce, Anthony

362

Steady-state thermal-hydraulic analysis of the pellet-bed reactor for nuclear thermal propulsion  

SciTech Connect

The pellet-bed reactor (PBR) for nuclear thermal propulsion is a hydrogen-cooled, BeO-reflected, fast reactor, consisting of an annular core region filled with randomly packed, spherical fuel pellets. The fuel pellets in the PBR are self-supported, eliminating the need for internal core structure, which simplifies the core design and reduces the size and mass of the reactor. Each spherical fuel pellet is composed of hundreds of fuel microspheres embedded in a zirconium carbide (ZrC) matrix. Each fuel microsphere is composed of a UC-NbC fuel kernel surrounded by two consecutive layers of the NbC and ZrC. Gaseous hydrogen serves both as core coolant and as the propellant for the PBR rocket engine. The cold hydrogen flows axially down the inlet channel situated between the core and the external BeO reflector and radially through the orifices in the cold frit, the core, and the orifices in the hot frit. Finally, the hot hydrogen flows axially out the central channel and exits through converging-diverging nozzle. A thermal-hydraulic analysis of the PBR core was performed with an emphasis on optimizing the size and axial distribution of the orifices in the hot and cold frits to ensure that hot spots would not develop in the core during full-power operation. Also investigated was the validity of the assumptions of neglecting the axial conduction and axial cross flow in the core.

El-Genk, M.S.; Morley, N.J.; Yang, J.Y. (Institute for Space Nuclear Power Studies, Albuquerque, NM (United States))

1992-01-01

363

Is incest common in gray wolf packs?  

USGS Publications Warehouse

Wolf packs generally consist of a breeding pair and their maturing offspring that help provision and protect pack young. Because the reproductive tenure in wolves often is short, reproductively mature offspring might replace their parents, resulting in sibling or parent-offspring matings. To determine the extent of incestuous pairings, we measure relatedness based on variability in 20 microsatellite loci of mated pairs, parent-offspring pairs and siblings in two populations of gray wolves. Our 16 sampled mated pairs had values of relatedness not overlapping those of known parent-offspring or sibling dyads, which is consistent with their being unrelated or distantly related. These results suggest that full siblings or a parent and their offspring rarely mate and that incest avoidance is an important constraint on gray wolf behavioral ecology.

Smith, D.; Meier, T.; Geffen, E.; Mech, L.D.; Burch, J.W.; Adams, L.G.; Wayne, R.K.

1997-01-01

364

Origins of Pulsing Regime in Cocurrent Packed-Bed Flows  

E-print Network

). A common configuration for carrying out such reactions is a three-phase packed- bed reactor, in whichOrigins of Pulsing Regime in Cocurrent Packed-Bed Flows B.A. Wilhite+ , B. Blackwell+ , J. Kacmar of the formation for cocurrent downflow pulse flow was studied experimentally in a packed-bed of inert spheres of 3

McCready, Mark J.

365

Pressure drop effects in packed capillary column supercritical fluid chromatography  

Microsoft Academic Search

The subject of column pressure drop has generated much controversy when using packed columns in supercritical fluid chromatography (SFC), since packed columns usually exhibit a ssignificant pressure drop along the column. In this paper, the effect of pressure drop on the chromatographic behavior of capillary columns packed with small spherical silica particles in SFC was studied using neat carbon dioxide

Wenbao Li; Abdul Malik; Milton L. Lee

1997-01-01

366

HIGH QUALITY ANISOTROPIC TETRAHEDRAL MESH GENERATION VIA ELLIPSOIDAL BUBBLE PACKING  

E-print Network

the behavior of soap bubbles in nature. If we pack soap bubbles in a volumetric domain, the bubblesHIGH QUALITY ANISOTROPIC TETRAHEDRAL MESH GENERATION VIA ELLIPSOIDAL BUBBLE PACKING Soji Yamakawa1 through a physically based particle simulation, which we call 'bubble packing.' Ellipsoidal bubbles

Shimada, Kenji

367

1. Contextual view looking west, showing packing house and Union ...  

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

1. Contextual view looking west, showing packing house and Union Ice building, which is located to the north of Packing House (right hand side in photo) - College Heights Lemon Packing House, 519-532 West First Street, Claremont, Los Angeles County, CA

368

36 CFR 2.16 - Horses and pack animals.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Horses and pack animals. 2.16 Section...PUBLIC USE AND RECREATION 2.16 Horses and pack animals. The following are...transporting equipment. (b) The use of horses or pack animals outside of trails,...

2010-07-01

369

36 CFR 1002.16 - Horses and pack animals.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Horses and pack animals. 1002.16 Section...PUBLIC USE AND RECREATION 1002.16 Horses and pack animals. The following are...transporting equipment. (b) The use of horses or pack animals outside of trails,...

2010-07-01

370

Force transmission in a packing of pentagonal particles  

Microsoft Academic Search

We perform a detailed analysis of the contact force network in a dense confined packing of pentagonal particles simulated by means of the contact dynamics method. The effect of particle shape is evidenced by comparing the data from pentagon packing and from a packing with identical characteristics, except for the circular shape of the particles. A counterintuitive finding of this

Emilien Azma; Farhang Radja; Robert Peyroux; Gilles Saussine

2007-01-01

371

Force transmission in a packing of pentagonal particles  

Microsoft Academic Search

We perform a detailed analysis of the contact force network in a dense confined packing of pen- tagonal particles simulated by means of the contact dynamics method. The effect of particle shape is evidenced by comparing the data from pentagon packing and from a packing with identical char- acteristics except for the circular shape of the particles. A counterintuitive finding

Emilien Azema; Farhang Radja; Robert Peyroux; Gilles Saussine

2007-01-01

372

ROV PACK: INFORMATION AND GUIDELINES www.serpentproject.com  

E-print Network

ROV PACK: INFORMATION AND GUIDELINES www.serpentproject.com SERPENT Project Office 496/02 National © 2008, SERPENT. CONFIDENTIAL. ALL RIGHTS RESERVED. #12;ROV PACK: INFORMATION AND GUIDELINES www WELCOME! A BRIEF INTRODUCTION 3 OUR DEEPWATER MISSION 3 OUR PRIORITIES 3 ROV PACKS 4 OUR LOCATIONS 5 AIMS

National Oceanography Centre, Southampton

373

Harmonic algorithm for 3-dimensional strip packing problem  

Microsoft Academic Search

In the three dimensional strip packing problem, we are given a set of three-dimensional rectangular items I = {(xi, yi, zi) : i = 1, ..., n} and a three dimensional box B. The goal is to pack all the items in the box B without any overlap, such that the height of the packing is minimized. We consider the

Nikhil Bansal; Xin Han; Kazuo Iwama; Maxim Sviridenko; Guochuan Zhang

2007-01-01

374

36 CFR 1002.16 - Horses and pack animals.  

...of horses or pack animals on trails, except...Allowing horses or pack animals to proceed in excess of a slow walk when passing in the immediate vicinity...considering the nature and purpose of...while horses or pack animals are passing....

2014-07-01

375

36 CFR 2.16 - Horses and pack animals.  

Code of Federal Regulations, 2012 CFR

...of horses or pack animals on trails, except...Allowing horses or pack animals to proceed in excess of a slow walk when passing in the immediate vicinity...considering the nature and purpose of...while horses or pack animals are passing....

2012-07-01

376

36 CFR 1002.16 - Horses and pack animals.  

Code of Federal Regulations, 2013 CFR

...of horses or pack animals on trails, except...Allowing horses or pack animals to proceed in excess of a slow walk when passing in the immediate vicinity...considering the nature and purpose of...while horses or pack animals are passing....

2013-07-01

377

36 CFR 1002.16 - Horses and pack animals.  

Code of Federal Regulations, 2011 CFR

...of horses or pack animals on trails, except...Allowing horses or pack animals to proceed in excess of a slow walk when passing in the immediate vicinity...considering the nature and purpose of...while horses or pack animals are passing....

2011-07-01

378

36 CFR 2.16 - Horses and pack animals.  

Code of Federal Regulations, 2013 CFR

...of horses or pack animals on trails, except...Allowing horses or pack animals to proceed in excess of a slow walk when passing in the immediate vicinity...considering the nature and purpose of...while horses or pack animals are passing....

2013-07-01

379

36 CFR 1002.16 - Horses and pack animals.  

Code of Federal Regulations, 2012 CFR

...of horses or pack animals on trails, except...Allowing horses or pack animals to proceed in excess of a slow walk when passing in the immediate vicinity...considering the nature and purpose of...while horses or pack animals are passing....

2012-07-01

380

36 CFR 2.16 - Horses and pack animals.  

Code of Federal Regulations, 2011 CFR

...of horses or pack animals on trails, except...Allowing horses or pack animals to proceed in excess of a slow walk when passing in the immediate vicinity...considering the nature and purpose of...while horses or pack animals are passing....

2011-07-01

381

77 FR 55770 - Airworthiness Directives; Cessna Aircraft Company Airplanes  

Federal Register 2010, 2011, 2012, 2013

...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

382

Trip packing in petrol stations replenishment  

Microsoft Academic Search

This paper considers a generalized version of the trip packing problem that we encountered as a sub-problem of the petrol stations replenishment problem. In this version we have to assign a number of trips to a fleet composed of a limited number of non-identical tank-trucks. Each trip has a specific duration, working time of vehicles is limited and the net

Fayez F. Boctor; Jacques Renaud; Fabien Cornillier

2011-01-01

383

Pressure tunes atomic packing in metallic glass  

Microsoft Academic Search

By employing the state-of-the-art in situ high-pressure synchrotron x-ray measurements and ab initio modeling, we have resolved atomic-level packing details in a metallic glass as a function of pressure. We demonstrate pronounced changes in atomic size ratio (and correspondingly coordination number) with increasing pressure and the accompanying conversion of prism-type coordination to icosahedral short-range order.

H. W. Sheng; E. Ma; H. Z. Liu; J. Wen

2006-01-01

384

Maximum Bounded Rooted-Tree Packing Problem  

E-print Network

Given a graph and a root, the Maximum Bounded Rooted-Tree Packing (MBRTP) problem aims at finding K rooted-trees that span the largest subset of vertices, when each vertex has a limited outdegree. This problem is motivated by peer-to-peer streaming overlays in under-provisioned systems. We prove that the MBRTP problem is NP-complete. We present two polynomial-time algorithms that computes an optimal solution on complete graphs and trees respectively.

Kerivin, Herve; Simon, Gwendal; Zhou, Fen

2011-01-01

385

Computational modelling of large aerated lagoon hydraulics.  

PubMed

A good understanding of the hydraulic performance of aerated lagoons is required for their design and operation. A comprehensive numerical procedure has been developed for the three-dimensional computational modelling of the flow in large lagoons including high-speed floating mechanical surface aerators. This paper describes the procedure that consists of separate aerator modelling, then applying the obtained results as boundary data for a full lagoon model. A model application to an industrial aerated lagoon serves as an example of flow analysis. Post processing of the results by calculating the local average residence time (age of fluid) provides a powerful and intuitive technique to visualize and analyse the lagoon performance. The model has been verified by comparing the local average residence time predictions with measurements from a dye study. It is shown that the numerical modelling proposed is feasible and constitutes an effective new tool in improving the performance and design of industrial lagoons. PMID:17418879

Pougatch, Konstantin; Salcudean, Martha; Gartshore, Ian; Pagoria, Philip

2007-05-01

386

PackHelix: a tool for helix-sheet packing during protein structure prediction  

PubMed Central

The three-dimensional structure of a protein is organized around the packing of its secondary structure elements. Predicting the topology and constructing the geometry of structural motifs involving ?-helices and/or ?-strands are therefore key steps for accurate prediction of protein structure. While many efforts have focused on how to pack helices and on how to sample exhaustively the topologies and geometries of multiple strands forming a ?-sheet in a protein, there has been little progress on generating native-like packing of helices on sheets. We describe a method that can generate the packing of multiple helices on a given ?-sheet for ??? sandwich type protein folds. This method mines the results of a statistical analysis of the conformations of ??2 motifs in protein structures to provide input values for the geometric attributes of the packing of a helix on a sheet. It then proceeds with a geometric builder that generates multiple arrangements of the helices on the sheet of interest by sampling through these values and performing consistency checks that guarantee proper loop geometry between the helices and the strands, minimal number of collisions between the helices, and proper formation of a hydrophobic core. The method is implemented as a module of ProteinShop. Our results show that it produces structures that are within 46 RMSD of the native one, regardless of the number of helices that need to be packed, though this number may increase if the protein has several helices between two consecutive strands in the sequence that pack on the sheet formed by these two strands. PMID:21905109

Hu, Chengcheng; Koehl, Patrice; Max, Nelson

2011-01-01

387

Probe with integrated heater and thermocouple pack  

DOEpatents

A probe for measuring heat includes an elongate rod fitted within a sheath, and a plurality of annular recesses are formed on the surface of the rod in a spaced-apart relationship to form annular chambers that are resistant to heat flow. A longitudinal bore extends axially into the rod and within the cylinders defined by the annular chambers, and an integrated heater and thermocouple pack is dimensioned to fit within the bore. In construction, the integrated pack includes a plurality of wires disposed in electrical insulation within a sheath and a heater cable. These wires include one common wire and a plurality of thermocuple wires. The common wire is constructed of one type of conductive material while the thermocouple wires are each constructed of two types of materials so that at least one thermocouple junction is formed therein. All of the wires extend the length of the integrated pack and are connected together at their ends. The thermocouple wires are constructed to form thermocouple junctions proximate to each annular chamber for producing electromotive forces corresponding to the temperature of the rod within the annular chambers relative to outside the chambers. In the preferred embodiment, each thermocouple wire forms two thermocouple junctions, one junction being disposed within an annular chamber and the second junction being disposed outside of, but proximate to, the same annular chamber. In one embodiment two thermocouple wires are configured to double the sensitivity of the probe in one region.

McCulloch, Reg W. (Oak Ridge, TN); Dial, Ralph E. (Concord, TN); Finnell, Wilber K. R. (Kingston, TN)

1990-01-01

388

Probe with integrated heater and thermocouple pack  

DOEpatents

A probe for measuring heat includes an elongate rod fitted within a sheath, and a plurality of annular recesses are formed on the surface of the rod in a spaced-apart relationship to form annular chambers that are resistant to heat flow. A longitudinal bore extends axially into the rod and within the cylinders defined by the annular chambers, and an integrated heater and thermocouple pack is dimensioned to fit within the bore. In construction, the integrated pack includes a plurality of wires disposed in electrical insulation within a sheath and a heater cable. These wires include one common wire and a plurality of thermocouple wires. The common wire is constructed of one type of conductive material while the thermocouple wires are each constructed of two types of materials so that at least one thermocouple junction is formed therein. All of the wires extend the length of the integrated pack and are connected together at their ends. The thermocouple wires are constructed to form thermocouple junctions proximate to each annular chamber for producing electromotive forces corresponding to the temperature of the rod within the annular chambers relative to outside the chambers. In the preferred embodiment, each thermocouple wire forms two thermocouple junctions, one junction being disposed within an annular chamber and the second junction being disposed outside of, but proximate to, the same annular chamber. In one embodiment two thermocouple wires are configured to double the sensitivity of the probe in one region.

McCulloch, Reginald W. (Oak Ridge, TN); Dial, Ralph E. (Concord, TN); Finnell, Wilber K. R. (Kingston, TN)

1988-01-01

389

Influence of fiber packing structure on permeability  

NASA Technical Reports Server (NTRS)

The study on the permeability of an aligned fiber bundle is the key building block in modeling the permeability of advanced woven and braided preforms. Available results on the permeability of fiber bundles in the literature show that a substantial difference exists between numerical and analytical calculations on idealized fiber packing structures, such as square and hexagonal packing, and experimental measurements on practical fiber bundles. The present study focuses on the variation of the permeability of a fiber bundle under practical process conditions. Fiber bundles are considered as containing openings and fiber clusters within the bundle. Numerical simulations on the influence of various openings on the permeability were conducted. Idealized packing structures are used, but with introduced openings distributed in different patterns. Both longitudinal and transverse flow are considered. The results show that openings within the fiber bundle have substantial effect on the permeability. In the longitudinal flow case, the openings become the dominant flow path. In the transverse flow case, the fiber clusters reduce the gap sizes among fibers. Therefore the permeability is greatly influenced by these openings and clusters, respectively. In addition to the porosity or fiber volume fraction, which is commonly used in the permeability expression, another fiber bundle status parameter, the ultimate fiber volume fraction, is introduced to capture the disturbance within a fiber bundle.

Cai, Zhong; Berdichevsky, Alexander L.

1993-01-01

390

Design of hydraulic output Stirling engine  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

391

Parenteral poppy seed tea packs a powerful punch.  

PubMed

Poppy seed tea (PST) has a long history of use for its medicinal (analgesic, anti-diarrhoeal, anxiolytic) effects. It is also commonly used as a recreational drug in its oral form throughout the world, but reports of intravenous use are very rare. We present two cases of intravenously injected PST with dramatic effects in order to create awareness among health professionals of this method of drug use and its potential complications, as well as to help clinicians dealing with opiate-dependent patients to warn them of the risk. PMID:24362742

Monaghan, Dominic; Peckler, Brad

2013-01-01

392

Volatile species in halide-activated-diffusion coating packs  

NASA Technical Reports Server (NTRS)

An atmospheric pressure sampling mass spectrometer was used to identify the vapor species generated in a halide-activated cementation pack. Pack powder mixtures containing a Cr-Al binary masteralloy powder, an NH4Cl activator salt, and either ZrO2 or Y2O3 (or neither) were analyzed at 1000 C. Both the equilibrium calculations for the pack and mass spectrometer results indicated that volatile AlCl(x) and CrCl(y) species were generated by the pack powder mixture; in packs containing the reactive element oxide, volatile ZrCl(z) and YCl(w) species were formed by the conversion of their oxide sources.

Bianco, Robert; Rapp, Robert A.; Jacobson, Nathan S.

1992-01-01

393

Vasopressin pack for treatment of bleeding after myoma resection.  

PubMed

In 17 women with refractory bleeding after myoma resection a dilute vasopressin pack was applied. Twenty units of vasopressin was diluted with 30 ml normal saline solution. A 1-inch new gauze pack was soaked in the dilute vasopressin and packed into the uteri of patients with bleeding from the beds of resected submucous myomas. The pack was left in place for no more than an hour. In none of the cases was there bleeding after the removal of the pack nor were there any side effects that could be attributed to the vasopressin. PMID:1957869

Townsend, D E

1991-11-01

394

Using Stream Leaf Packs to Explore Community Assembly  

NSDL National Science Digital Library

In this TIEE experiment, students will explore functional and taxonomic diversity in a stream ecosystem, learn about food web relationships, and learn about the ways in which abiotic and biotic factors determine what organisms are present in a community. Students will make and install artificial leaf packs in a stream, wait for the leaf packs to be colonized by stream organisms, measure abiotic variables that could influence leaf pack colonization, retrieve the leaf packs and classify the organisms they find in both taxonomic and functional ways, and participate in a class discussion of how the leaf pack community is situated within a larger ecosystem.

Hartley, Laurel

2011-08-29

395

Dense packings of polyhedra: Platonic and Archimedean solids  

NASA Astrophysics Data System (ADS)

Understanding the nature of dense particle packings is a subject of intense research in the physical, mathematical, and biological sciences. The preponderance of previous work has focused on spherical particles and very little is known about dense polyhedral packings. We formulate the problem of generating dense packings of nonoverlapping, nontiling polyhedra within an adaptive fundamental cell subject to periodic boundary conditions as an optimization problem, which we call the adaptive shrinking cell (ASC) scheme. This optimization problem is solved here (using a variety of multiparticle initial configurations) to find the dense packings of each of the Platonic solids in three-dimensional Euclidean space R3 , except for the cube, which is the only Platonic solid that tiles space. We find the densest known packings of tetrahedra, icosahedra, dodecahedra, and octahedra with densities 0.823, 0.836, 0.904, and 0.947, respectively. It is noteworthy that the densest tetrahedral packing possesses no long-range order. Unlike the densest tetrahedral packing, which must not be a Bravais lattice packing, the densest packings of the other nontiling Platonic solids that we obtain are their previously known optimal (Bravais) lattice packings. We also derive a simple upper bound on the maximal density of packings of congruent nonspherical particles and apply it to Platonic solids, Archimedean solids, superballs, and ellipsoids. Provided that what we term the asphericity (ratio of the circumradius to inradius) is sufficiently small, the upper bounds are relatively tight and thus close to the corresponding densities of the optimal lattice packings of the centrally symmetric Platonic and Archimedean solids. Our simulation results, rigorous upper bounds, and other theoretical arguments lead us to the conjecture that the densest packings of Platonic and Archimedean solids with central symmetry are given by their corresponding densest lattice packings. This can be regarded to be the analog of Keplers sphere conjecture for these solids. The truncated tetrahedron is the only non-centrally symmetric Archimedean solid, the densest known packing of which is a non-lattice packing with density at least as high as 23/24=0.958333 . We discuss the validity of our conjecture to packings of superballs, prisms, and antiprisms as well as to high-dimensional analogs of the Platonic solids. In addition, we conjecture that the optimal packing of any convex, congruent polyhedron without central symmetry generally is not a lattice packing. Finally, we discuss the possible applications and generalizations of the ASC scheme in predicting the crystal structures of polyhedral nanoparticles and the study of random packings of hard polyhedra.

Torquato, S.; Jiao, Y.

2009-10-01

396

Development of a HydroMechanical Hydraulic Hybrid Drive Train with Independent Wheel Torque Control for an Urban Passenger Vehicle  

Microsoft Academic Search

This paper presents a hydraulic hybrid vehicle drive train to improve the fuel efficiency of a passenger car. The developed hydro-mechanical drive train enables independent control of the torque at each wheel. The motivation for developing this drive train is a hydraulic hybrid vehicle test bed for the Center for Compact and Efficient Fluid Power at the University of Minnesota.

James D. Van de Ven; Michael W. Olson; Perry Y. Li

397

Hydraulic wellbore erosion while drilling  

SciTech Connect

This article is the first to identify nozzle hydraulic effects in a field evaluation of hole erosion. Common practice normally identifies annular velocity as the culprit for excessive hole washout. But field tests in this article clearly identify excessive nozzle hydraulics as the cause for hole erosion. Both oil-based and water-based drilling fluids were used during the field test. The primary contribution of this study is a simple guideline to assist drillers in preventing excessive hole erosion. This article describes drilling conditions and caliper logs, and discusses sequences of events that could explain the observations. Some preliminary guidelines are presented so that drillers can prevent erosion of the wellbore from high shear rates at bit nozzles.

Chemerinski, B. [British Borneo Exploration, Houston, TX (United States); Robinson, L. [OGCI, Houston, TX (United States)

1996-12-01

398

Non-Euclidean geometry of twisted filament bundle packing  

PubMed Central

Densely packed and twisted assemblies of filaments are crucial structural motifs in macroscopic materials (cables, ropes, and textiles) as well as synthetic and biological nanomaterials (fibrous proteins). We study the unique and nontrivial packing geometry of this universal material design from two perspectives. First, we show that the problem of twisted bundle packing can be mapped exactly onto the problem of disc packing on a curved surface, the geometry of which has a positive, spherical curvature close to the center of rotation and approaches the intrinsically flat geometry of a cylinder far from the bundle center. From this mapping, we find the packing of any twisted bundle is geometrically frustrated, as it makes the sixfold geometry of filament close packing impossible at the core of the fiber. This geometrical equivalence leads to a spectrum of close-packed fiber geometries, whose low symmetry (five-, four-, three-, and twofold) reflect non-Euclidean packing constraints at the bundle core. Second, we explore the ground-state structure of twisted filament assemblies formed under the influence of adhesive interactions by a computational model. Here, we find that the underlying non-Euclidean geometry of twisted fiber packing disrupts the regular lattice packing of filaments above a critical radius, proportional to the helical pitch. Above this critical radius, the ground-state packing includes the presence of between one and six excess fivefold disclinations in the cross-sectional order. PMID:22711799

Bruss, Isaac R.; Grason, Gregory M.

2012-01-01

399

Hydraulic redistribution may stimulate decomposition  

Microsoft Academic Search

Roots influence root litter decomposition through multiple belowground processes. Hydraulic lift or redistribution (HR) by\\u000a plants is one such process that creates diel dryingrewetting cycles in soil. However, it is unclear if this phenomenon influences\\u000a decomposition. Since decomposition in deserts is constrained by low soil moisture and is stimulated when dry soils are rewetted,\\u000a we hypothesized that diel dryingrewetting, via

Zachary T. Aanderud; James H. Richards

2009-01-01

400

Strain Stiffening in Random Packings of Entangled Granular Chains  

SciTech Connect

Random packings of granular chains are presented as a model system to investigate the contribution of entanglements to strain stiffening. The chain packings are sheared in uniaxial compression experiments. For short chain lengths, these packings yield when the shear stress exceeds the scale of the confining pressure, similar to granular packings of unconnected particles. In contrast, packings of chains which are long enough to form loops exhibit strain stiffening, in which the effective stiffness of the material increases with strain, similar to many polymer materials. The latter packings can sustain stresses orders-of-magnitude greater than the confining pressure, and do not yield until the chain links break. X-ray tomography measurements reveal that the strain-stiffening packings contain system-spanning clusters of entangled chains.

Brown, Eric; Nasto, Alice; Athanassiadis, Athanasios G.; Jaeger, Heinrich M. (UC)

2012-04-02

401

The application of hydraulics in the 2,000 kW wind turbine generator  

NASA Technical Reports Server (NTRS)

A 2000 kW turbine generator using hydraulic power in two of its control systems is being built under the management of NASA Lewis Research Center. The hydraulic systems providing the control torques and forces for the yaw and blade pitch control systems are discussed. The yaw-drive-system hydraulic supply provides the power for positioning the nacelle so that the rotary axis is kept in line with the direction of the prevailing wind, as well as pressure to the yaw and high speed shaft brakes. The pitch-change-mechanism hydraulic system provides the actuation to the pitch change mechanism and permits feathering of the blades during an emergency situation. It operates in conjunction with the overall windmill computer system, with the feather control permitting slewing control flow to pass from the servo valve to the actuators without restriction.

Onufreiczuk, S.

1978-01-01

402

Mapping the distribution of packing topologies within protein interiors shows predominant preference for specific packing motifs  

PubMed Central

Background Mapping protein primary sequences to their three dimensional folds referred to as the 'second genetic code' remains an unsolved scientific problem. A crucial part of the problem concerns the geometrical specificity in side chain association leading to densely packed protein cores, a hallmark of correctly folded native structures. Thus, any model of packing within proteins should constitute an indispensable component of protein folding and design. Results In this study an attempt has been made to find, characterize and classify recurring patterns in the packing of side chain atoms within a protein which sustains its native fold. The interaction of side chain atoms within the protein core has been represented as a contact network based on the surface complementarity and overlap between associating side chain surfaces. Some network topologies definitely appear to be preferred and they have been termed 'packing motifs', analogous to super secondary structures in proteins. Study of the distribution of these motifs reveals the ubiquitous presence of typical smaller graphs, which appear to get linked or coalesce to give larger graphs, reminiscent of the nucleation-condensation model in protein folding. One such frequently occurring motif, also envisaged as the unit of clustering, the three residue clique was invariably found in regions of dense packing. Finally, topological measures based on surface contact networks appeared to be effective in discriminating sequences native to a specific fold amongst a set of decoys. Conclusions Out of innumerable topological possibilities, only a finite number of specific packing motifs are actually realized in proteins. This small number of motifs could serve as a basis set in the construction of larger networks. Of these, the triplet clique exhibits distinct preference both in terms of composition and geometry. PMID:21605466

2011-01-01

403

Gas Distribution in Shallow Packed Beds.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. Packed beds have many industrial applications and are increasingly used in the process industries due to their low pressure drop. Obtaining uniform gas distribution in such beds is of crucial importance in minimising operating costs and optimising plant performance. Since to some extent a packed bed acts as its own distributor the importance of obtaining uniform gas distribution has increased as aspect ratios (bed height to diameter) decrease. There is no rigorous design method for distributors due to a limited understanding of the fluid flow phenomena and in particular of the effect of the bed base/free fluid interface. This study is based on a combined theoretical and modelling approach. The Ergun Equation is used to determine the pressure drop over a bed where the flow is uni-directional. This equation has been used in a vectorial form so that it can be applied to maldistributed and multi -directional flows and has been realised in the Computational Fluid Dynamics code PHOENICS. The use of this equation and its application has been verified by modelling experimental measurements of maldistributed gas flows, where there is no free fluid/bed base interface. A novel, two-dimensional experiment has been designed to investigate the fluid mechanics of maldistributed gas flows in shallow packed beds. The results from this apparatus provide useful insights into the fluid mechanics of flow in and around a shallow packed bed and show the critical effect of the bed base. The PHOENICS/vectorial Ergun Equation model has been adapted to model this situation. The model has been improved by the inclusion of spatial voidage variations in the bed and the prescription of a novel bed base boundary condition. The flow in a curved bed section, which is three -dimensional in nature, is examined experimentally. The effect of the walls and the changes in gas direction on the gas flow are shown to be particularly significant. The model and improved understanding of the underlying physical phenomena form the basis for the development of new distributors and rigorous design methods for them. (Abstract shortened by UMI.).

Parsons, Ian Miles

404

Packed fluidized bed blanket for fusion reactor  

DOEpatents

A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

Chi, John W. H. (Mt. Lebanon, PA)

1984-01-01

405

Comparing Online Algorithms for Bin Packing Problems  

E-print Network

Abstract The relative worst-order ratio is a measure of the quality of online algorithms. In contrast to the competitive ratio, this measure compares two online algorithms directly instead of using an intermediate comparison with an optimal offline algorithm. In this paper, we apply the relative worst-order ratio to online algorithms for several common variants of the bin packing problem. We mainly consider pairs of algorithms that are not distinguished by the competitive ratio and show that the relative worst-order ratio prefers the intuitively better algorithm of each pair.

Leah Epstein; Lene M. Favrholdt; Jens S. Kohrt

406

Radiative transfer in closely packed realistic regoliths  

NASA Astrophysics Data System (ADS)

We have developed a regolith radiative transfer model (RRT) based on a first-principles approach to regolith modeling that is essential for near-to-far infrared observations of grainy surfaces, and is readily configured to answer fundamental questions about popular models with which all remote observations of all airless solar system bodies with granular surfaces are currently interpreted. Our model accounts for wavelength-size regolith particles which are closely packed and can be heterogeneous in composition and arbitrarily shaped. Here we present preliminary results showing the role of porosity on layer reflectivity.

Vahidinia, S.; Cuzzi, J.; Draine, B.; Marouf, E.

2011-10-01

407

Considerations for Modeling Bacterial-Induced Changes in Hydraulic Properties of Variably Saturated Porous Media  

SciTech Connect

Bacterial-induced changes in the hydraulic properties of porous media are important in a variety of disciplines. Most of the pervious research on this topic has focused on liquid-saturated porous media systems that are representative of aquifer sediments. Unsaturated or variably saturated systems such as soils require additional considerations that have not been fully addressed in the literature. This paper reviews some of the earlier studies on bacterial-induced changes in the hydraulic properties of saturated porous media, and discusses characteristics of unsaturated or variably saturated porous media that may be important to consider when modeling such phenomena in these systems. New data are presented from experiments conducted in sand-packed columns with initially steady unsaturated flow conditions that show significant biomass-induced changes in pressure heads and water contents and permeability reduction during growth of a Pseudomonas fluorescens bacterium.

Rockhold, Mark L.; Yarwood, R. R.; Niemet, Michael R.; Bottomley, Peter J.; Selker, John S.

2002-07-26

408

Considerations for modeling bacterial-induced changes in hydraulic properties of variably saturated porous media  

NASA Astrophysics Data System (ADS)

Bacterial-induced changes in the hydraulic properties of porous media are important in a variety of disciplines. Most of the previous research on this topic has focused on liquid-saturated porous media systems that are representative of aquifer sediments. Unsaturated or variably saturated systems such as soils require additional considerations that have not been fully addressed in the literature. This paper reviews some of the earlier studies on bacterial-induced changes in the hydraulic properties of saturated porous media, and discusses characteristics of unsaturated or variably saturated porous media that may be important to consider when modeling such phenomena in these systems. New data are presented from experiments conducted in sand-packed columns with initially steady unsaturated flow conditions that show significant biomass-induced changes in pressure heads and water contents and permeability reduction during growth of a Pseudomonas fluorescens bacterium.

Rockhold, M. L.; Yarwood, R. R.; Niemet, M. R.; Bottomley, P. J.; Selker, J. S.

409

Young adult smokers perceptions of cigarette pack innovation, pack colour and plain packaging  

Microsoft Academic Search

In jurisdictions where most forms of marketing tobacco are prohibited by law, such as the United Kingdom (UK), the tobacco industry is increasingly turning to innovative packaging to promote their products. Using focus group research we explored perceptions of packaging innovation (including cigarette packs with novel shapes and method of opening), and also plain packaging (all branding removed), among 54

Crawford Moodie; Allison Ford

2011-01-01

410

Optimal packing of a rotating packed bed for H(2)S removal.  

PubMed

The existence of H2S in a system could lead to catalyst deactivation, pipeline corrosion, and environmental pollution. A rotating packed bed (RPB), a novel reactor with high mass transfer efficiency and small dimension, is employed in this study to remove H2S. For RPB, the most significant section for mass transfer is the end-effect zone of packing. A mathematical model for liquid flow in the packing is established to quantify the length of the end-effect zone. A simple and effective visual experimental method is then proposed to investigate the end-effect zone in the RPB. A gas-liquid mass transfer experiment is finally employed to confirm the validity of the proposed mathematical model. With the aid of this model, the length of packing of a RPB used for pilot-scale H2S removal is optimized. The optimized RPB removes 99.8% of H2S (15 vol % to 0.03 vol %) from the system. The proposed model can help optimize the design of a RPB reactor. PMID:24798198

Guo, Kai; Wen, Jiawu; Zhao, Ying; Wang, Yu; Zhang, Zhenzhen; Li, Zongxiang; Qian, Zhi

2014-06-17

411

Sound wave velocities in dry and lubricated granular packings packings: numerical simulations and experiments  

Microsoft Academic Search

Numerical simulations are used to investigate the origins of the different wave velocities measured in dense granular samples assembled with different methods. Glass bead packings are prepared in the lab either by pouring and vibrating the dry material in a container, or by mixing with a very small amount of a viscous lubricant. Lubricated samples, although less dense, exhibit significantly

Ivana Agnolin; Jean-Nol Roux; Pascal Massaad; Xiaoping Jia; Pierre Mills

2009-01-01

412

Effective Thermal Conductivity of Adsorbent Packed Beds  

NASA Astrophysics Data System (ADS)

The effective thermal conductivity of adsorbent packed beds of granular zeolite 13X and granular silica gel A in the presence of stagnant steam or air was measured under different conditions of the adsorbent bed temperature, particle size and filler-gas pressure. The measured effective thermal conductivity showed to become smaller with decreasing particle size or decreasing pressure, but it was nearly independent of the bed temperature. When steam was the filler-gas, the rise in the thermal conductivity of the adsorbent particles due to steam adsorption led to the increase in the effective thermal conductivity of the bed, and this effect was not negligible at high steam pressure for the bed of large particle size. It was found that both the predictions of the effective thermal conductivity by the Hayashi et al.'s model and the Bauer-Schlnder model generally agreed well with the measurements, by considering the particle thermal conductivity rise due to steam adsorption. The thermal conductivity of a consolidated bed of granular zeolite 13X was also measured, and it was found to be much larger than that of the packed bed especially at lower pressure. The above prediction models underestimated the effective thermal conductivity of the consolidated bed.

Mori, Hideo; Hamamoto, Yoshinori; Yoshida, Suguru

413

Understanding shape entropy through local dense packing.  

PubMed

Entropy drives the phase behavior of colloids ranging from dense suspensions of hard spheres or rods to dilute suspensions of hard spheres and depletants. Entropic ordering of anisotropic shapes into complex crystals, liquid crystals, and even quasicrystals was demonstrated recently in computer simulations and experiments. The ordering of shapes appears to arise from the emergence of directional entropic forces (DEFs) that align neighboring particles, but these forces have been neither rigorously defined nor quantified in generic systems. Here, we show quantitatively that shape drives the phase behavior of systems of anisotropic particles upon crowding through DEFs. We define DEFs in generic systems and compute them for several hard particle systems. We show they are on the order of a few times the thermal energy ([Formula: see text]) at the onset of ordering, placing DEFs on par with traditional depletion, van der Waals, and other intrinsic interactions. In experimental systems with these other interactions, we provide direct quantitative evidence that entropic effects of shape also contribute to self-assembly. We use DEFs to draw a distinction between self-assembly and packing behavior. We show that the mechanism that generates directional entropic forces is the maximization of entropy by optimizing local particle packing. We show that this mechanism occurs in a wide class of systems and we treat, in a unified way, the entropy-driven phase behavior of arbitrary shapes, incorporating the well-known works of Kirkwood, Onsager, and Asakura and Oosawa. PMID:25344532

van Anders, Greg; Klotsa, Daphne; Ahmed, N Khalid; Engel, Michael; Glotzer, Sharon C

2014-11-11

414

Packing material formulation for odorous emission biofiltration.  

PubMed

In biological gas treatment, like biofiltration of volatile organic compounds or odorous substances, the microbial nutritional needs could be a key factor of the process. The aim of this work is to propose a new packing material able to provide the lacking nutrients. In the first part of this study, two kinds of material composed of calcium carbonate, an organic binder and two different nitrogen sources, ammonium phosphate and urea phosphate (UP), were compared. The new supports present bulk densities between 0.88 and 1.15g cm(-3), moisture retention capacities close to 50% and 70%, and water cohesion capacities greater than six months for the material with 20% binder. In the second part, oxygen consumption measurements in liquid experiments show that these packing materials could enhance bacterial growth compared to pine bark or pozzolan and have no inhibitory effect. The biodegradation of different substrates (sodium sulfide and ammonia) and the support colonization by the biomass were evaluated. Finally, UP 20 was chosen and tested in a hydrogen sulfide or ammoniac biofiltration process. This showed that, for H2S concentrations greater than 100mg m(-3), UP 20 has a real advantage over pine bark or pozzolan. PMID:17889256

Gaudin, Franois; Andres, Yves; Le Cloirec, Pierre

2008-01-01

415

Combined hydraulic and regenerative braking system  

DOEpatents

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 at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.

Venkataperumal, Rama R. (Troy, MI); Mericle, Gerald E. (Mount Clemens, MI)

1981-06-02

416

Combined hydraulic and regenerative braking system  

SciTech Connect

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 regenerative at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.

Mericle, G.E.; Venkataperumal, R.R.

1981-06-02

417

Fault Detection and Isolation for Hydraulic Control  

NASA Technical Reports Server (NTRS)

Pressure sensors and isolation valves act to shut down defective servochannel. Redundant hydraulic system indirectly senses failure in any of its electrical control channels and mechanically isolates hydraulic channel controlled by faulty electrical channel so flat it cannot participate in operating system. With failure-detection and isolation technique, system can sustains two failed channels and still functions at full performance levels. Scheme useful on aircraft or other systems with hydraulic servovalves where failure cannot be tolerated.

1987-01-01

418

Hydraulic Extractor For Electronic Connectors  

NASA Technical Reports Server (NTRS)

Tool separates multipin electrical connectors in electronic equipment. Based on use of hydraulic pressure to apply balanced forces to connector and gently pull it free without damage. Easily assembled from readily available parts. Includes actuator syringe, two extractor syringes of disposable plastic 5-mL type, several pieces of flexible plastic tubing, and adjustable mounting components that brace tool in desired spacing configuration to suit connector extracted. Tubes and syringes filled with suitable fluid. Designed specifically for use on "D"-type connectors, also adapted for use wherever linear extraction motion used.

Smith, Larry D.

1994-01-01

419

RELAP5-3D Thermal Hydraulics Computer Program Analysis Coupled with DAKOTA and STAR-CCM+ Codes  

E-print Network

, and thermal-hydraulic parameters which caused greatest sensitivity where identified: inlet core temperature and reactor thermal power. These variables, along with break size and discharge coefficients, were used for further investigation of the sensitivity...

Rodriguez, Oscar

2012-12-06

420

Monitoring hydraulic fracture growth: Laboratory experiments  

SciTech Connect

The authors carry out small-scale hydraulic fracture experiments to investigate the physics of hydraulic fracturing. The laboratory experiments are combined with time-lapse ultrasonic measurements with active sources using both compressional and shear-wave transducers. For the time-lapse measurements they focus on ultrasonic measurement changes during fracture growth. As a consequence they can detect the hydraulic fracture and characterize its shape and geometry during growth. Hence, this paper deals with fracture characterization using time-lapse acoustic data. Hydraulic fracturing is used in the oil and gas industry to stimulate reservoir production.

Groenenboom, J.; Dam, D.B. van

2000-04-01

421

Power  

NASA Technical Reports Server (NTRS)

The space station requires an increase in power or energy of at least several orders of magnitude compared to previous space missions. With the requirement up in the range of 10 kilowatt hours, this obviiously requires the development of new technology. Although the power area is very well integrated in the spacecraft itself, it represents a diverse set of components necessary for energy conversion, electronics, and energy distribution. Considerable work is ongoing at NASA Lewis in the power devices development area, including transformers, large area solid-state chips, transistors, and fast recovery diodes. This work is oriented toward eventual application to both AC and DC power conversion approaches. In the energy storage area, there are many options available to fit into the space station representing various degrees of risk and leverage combination, such as the near-term integral-pressure-vessel nickel hydrogen battery, an advanced Ni-H2 battery concept, and the regenrative hydrogen-oxygen system utilizing essentially the Shuttle orbiter type of fuel cell.

Corbett, R.

1984-01-01

422

Continuous phosphorus removal from water by physicochemical method using zero valent iron packed column.  

PubMed

Excessive phosphorus in aquatic systems causes algal bloom resulting in eutrophication. To treat wastewater including effluent of wastewater treatment plant containing various amounts of phosphorus, a series of continuous experiments on removal of phosphorus from water were performed by using an electrochemical method. The spherical type of zero valent iron (ZVI) and silica sand were packed at appropriate volume ratio of 1:2 in a cylindrical column. An electric potential was applied externally, which can be changed as per the operational requirement. The results indicate that optimum hydraulic retention time of 36 min was required to meet the effluent standards with our laboratory-scale experimental setup. Lower amounts of phosphorus were removed by precipitation due to contact with iron, and additional electric potential was not required. In order to remove high amounts of phosphorus (around 150 mg/L as phosphate), external electric potential of 600 V was applied to the reactor. As the precipitation of phosphate mainly occurs at neutral pH, it is likely that FeHPO4 will be the main phosphorus-containing compound. Through the results of the large-scale experiments, the ZVI packed reactor can be used as a filter for removal of phosphorus of less than 10 mg/L as phosphate concentration. PMID:25225938

Jeong, Joo-Young; Ahn, Byoung-Min; Kim, Yu-Jin; Park, Joo-Yang

2014-01-01

423

Column performance of granular activated carbon packed bed for Pb(II) removal.  

PubMed

The excessive release of lead from lead acid batteries, smelting plant into the environment is a major concern worldwide. Adsorption process is among the most effective techniques for lead removal from wastewater and activated carbon has been widely used as an adsorbent. In this paper an attempt has been made to investigate the adsorption behaviour of Pb(II) from aqueous systems onto granular activated carbon using the batch mode and continuous mode in a packed bed column with more successive service and regeneration. The experiments were performed at constant temperature and dimensions of column and packed bed of granular activated carbon with variation of flows through the bed and concentrations of lead solutions. Breakthrough points were found out for the adsorption of lead on the adsorbent using continuous-flow column operation by varying different operating parameters like hydraulic loading rate from 4 to 16 m(3)/h m(2) and feed concentrates from 20 to 60 mg/l. Granular activated carbon column regeneration using 0.5 M concentration of HNO(3) has been investigated. Results indicate encouraging performance towards removal of Pb(II). PMID:18249492

Dwivedi, Chandra P; Sahu, J N; Mohanty, C R; Mohan, B Raj; Meikap, B C

2008-08-15

424

Wave-operated power plant  

Microsoft Academic Search

This wave-operated power plant comprises a perforated caisson breakwater in which propellers, or turbines, are mounted in the perforations or openings and drives hydraulic pumps connected thereto, which in turn drives a hydraulic motor coupled to an electric generator. One-way flap valves are mounted in the openings. Some of said flap valves allow the rushing waves to enter the caisson,

Ghesquiere

1980-01-01

425

Redesign of the SNS Modulator H-Bridge for Utilization of Press-Pack IGBTs  

SciTech Connect

The power conversion group at SLAC is currently redesigning the H-bridge switch plates of the High Voltage Converter Modulators at the Spallation Neutron Source. This integral part to the modulator operation has been indentified as a source of several modulator faults and potentially limits reliability with pulse width modulation operation. This paper is a presentation of the design and implementation of a redesigned switch plate based upon press-pack IGBTs.

Kemp, Mark A.; Burkhart, Craig; /SLAC; Anderson, David E.; /Oak Ridge

2008-09-25

426

Basin filling algorithm for the circular packing problem with equilibrium behavioral constraints  

Microsoft Academic Search

With the background of the satellite module layout design, the circular packing problem with equilibrium behavioral constraints\\u000a is a layout optimization problem and NP-hard problem in math. For lack of a powerful optimization method, this problem is\\u000a hard to solve. The energy landscape paving (ELP) method is a class of stochastic global optimization algorithms based on the\\u000a Monte Carlo sampling.

JingFa Liu; Gang Li

2010-01-01

427

Performance characteristics of an electric vehicle lead-acid battery pack at elevated temperatures  

NASA Technical Reports Server (NTRS)

Discharge testing data electric car battery pack over initial electrolyte temperature variations between 27 and 55 C are presented. The tests were conducted under laboratory conditions and then compared to detailed electric vehicle simulation models. Battery discharge capacity increased with temperature for constant current discharges, and battery energy capacity increased with temperature for constant power discharges. Dynamometer tests of the electric test vehicle showed an increase in range of 25% for the higher electrolyte temperature.

Chapman, P.

1982-01-01

428

Characterization of aquifer heterogeneity using transient hydraulic tomography  

Microsoft Academic Search

Hydraulic tomography is a cost-effective technique for characterizing the heterogeneity of hydraulic parameters in the subsurface. During hydraulic tomography surveys a large number of hydraulic heads (i.e., aquifer responses) are collected from a series of pumping or injection tests in an aquifer. These responses are then used to interpret the spatial distribution of hydraulic parameters of the aquifer using inverse

Junfeng Zhu; Tian-Chyi J. Yeh

2005-01-01

429

Packed bed carburization of tantalum and tantalum alloy  

DOEpatents

Packed bed carburization of a tantalum or tantalum alloy object is disclosed. A method for producing corrosion-resistant tantalum or tantalum alloy objects is described. The method includes the steps of placing the object in contact with a carburizing pack, heating the packed object in vacuum furnace to a temperature whereby carbon from the pack diffuses into the object forming grains with tantalum carbide along the grain boundaries, and etching the surface of the carburized object. This latter step removes tantalum carbides from the surface of the carburized tantalum object while leaving the tantalum carbide along the grain boundaries. 4 figs.

Lopez, P.C.; Rodriguez, P.J.; Pereyra, R.A.

1999-06-29

430

Packed bed carburization of tantalum and tantalum alloy  

DOEpatents

Packed bed carburization of a tantalum or tantalum alloy object. A method for producing corrosion-resistant tantalum or tantalum alloy objects is described. The method includes the steps of placing the object in contact with a carburizing pack, heating the packed object in vacuum furnace to a temperature whereby carbon from the pack diffuses into the object forming grains with tantalum carbide along the grain boundaries, and etching the surface of the carburized object. This latter step removes tantalum carbides from the surface of the carburized tantalum object while leaving the tantalum carbide along the grain boundaries.

Lopez, Peter C. (Espanola, NM); Rodriguez, Patrick J. (Espanola, NM); Pereyra, Ramiro A. (Medanales, NM)

1999-01-01

431

Flow characterization using PIV measurements in a low aspect ratio randomly packed porous bed  

NASA Astrophysics Data System (ADS)

Low aspect ratio porous beds (bed width to bead diameter) have engineering applications such as catalytic reactors, combustors and heat exchangers. The nature of the packing within the bed and the influence of the near-wall region especially for randomly packed beds are expected to affect the velocity field and consequently the statistical characteristics of the flow. Planar PIV measurements were taken using refractive index matching at discrete locations throughout a randomly packed bed with aspect ratio of 4.67 for steady, low pore Reynolds number flows, Re pore ~ 4. Details of the measurement uncertainties as well as methods to determine local magnification and determination of the dynamic velocity range are presented. The data are analyzed using the PIV correlation averaging method with the largest velocity uncertainties arising from out-of-plane motion. Results show the correspondence with the geometric and velocity correlation functions across the bed and that the centerline of the bed shows a random-like distribution of velocity with an integral length scale on the order of one hydraulic diameter (or 0.38 bead diameters based on the porosity for this bed). The velocity variance is shown to increase by a factor of 1.8 when comparing the center plane data versus using data across the entire bed. It is shown that the large velocity variance contributes strongly to increased dispersion estimates and that based on the center plane data of the variance and integral length scales, the dispersion coefficient matches well with that measured in high aspect ratio beds using global data.

Patil, Vishal A.; Liburdy, James A.

2013-04-01

432

Control rod drive hydraulic system  

DOEpatents

A hydraulic system for a control rod drive (CRD) includes a variable output-pressure CR pump operable in a charging mode for providing pressurized fluid at a charging pressure, and in a normal mode for providing the pressurized fluid at a purge pressure, less than the charging pressure. Charging and purge lines are disposed in parallel flow between the CRD pump and the CRD. A hydraulic control unit is disposed in flow communication in the charging line and includes a scram accumulator. An isolation valve is provided in the charging line between the CRD pump and the scram accumulator. A controller is operatively connected to the CRD pump and the isolation valve and is effective for opening the isolation valve and operating the CRD pump in a charging mode for charging the scram accumulator, and closing the isolation valve and operating the CRD pump in a normal mode for providing to the CRD through the purge line the pressurized fluid at a purge pressure lower than the charging pressure.

Ose, Richard A. (San Jose, CA)

1992-01-01

433

Centrifugal compression of soft particle packings: theory and experiment.  

PubMed

An exact method is developed for computing the height of an elastic medium subjected to centrifugal compression, for arbitrary constitutive relation between stress and strain. Example solutions are obtained for power-law media and for cases where the stress diverges at a critical strain--for example as required by packings composed of deformable but incompressible particles. Experimental data are presented for the centrifugal compression of thermo-responsive N-isopropylacrylamide (NIPA) microgel beads in water. For small radial acceleration, the results are consistent with Hertzian elasticity, and are analyzed in terms of the Young elastic modulus of the bead material. For large radial acceleration, the sample compression asymptotes to a value corresponding to a space-filling particle volume fraction of unity. Therefore we conclude that the gel beads are incompressible, and deform without deswelling. In addition, we find that the Young elastic modulus of the particulate gel material scales with cross-link density raised to the power 3.30.8, somewhat larger than the Flory expectation. PMID:21230273

Nordstrom, K N; Verneuil, E; Ellenbroek, W G; Lubensky, T C; Gollub, J P; Durian, D J

2010-10-01

434

Thermal vacancies in close-packing solids  

E-print Network

Based on Stillinger's version of cell cluster theory, we derive an expression for the equilibrium concentration of thermal monovacancies in solids which allows for a transparent interpretation of the vacancy volume and the energetic/entropic part in the corresponding Gibbs energy of vacancy formation $\\Delta G_{\\rm v}$. For the close--packing crystals of the hard sphere and Lennard--Jones model systems very good agreement with simulation data is found. Application to metals through the embedded--atom method (EAM) reveals a strong sensitivity of the variation of $\\Delta G_{\\rm v}$ with temperature to details of the EAM potential. Our truncation of the cell cluster series allows for an approximate, but direct measurement of crystal free energies and vacancy concentration in colloidal model systems using laser tweezers.

Mostafa Mortazavifar; Martin Oettel

2013-11-20

435

K.K. Gan ATLAS Opto-Pack Review 1 Report on OSU Opto-Pack Prototypes  

E-print Network

material tested: aluminum silicate and macor difficult to obtain consistent precision ! redesign base ! no degradation observed #12;K.K. Gan ATLAS Opto-Pack Review 20 PIN Opto-pack Responsivity q PIN opto-pack responsivity is above spec. 0 0.2 0.4 0.6 0.8 1 0 1 2 3 4 5 6 7 Responsivity Trial specification #12;K.K. Gan

Gan, K. K.

436

Hydraulic Actuator for Ganged Control Rods  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

437

Geostatistical Estimations of Regional Hydraulic Conductivity Fields  

Microsoft Academic Search

Direct and indirect measurements of hydraulic conductivity (K) are commonly performed, providing information on the magnitude of this parameter at the local scale (tens of centimeters to hundreds of meters) and at shallow depths. By contrast, field information on hydraulic conductivities at regional scales of tens to hundreds of kilometers and at greater depths is relatively scarce. Geostatistical methods allow

D. Patriarche; M. C. Castro; P. Goovaerts

2004-01-01

438

Two new advances in well hydraulics  

Microsoft Academic Search

1) Shape factors for double-packer permeameters. The double-packer permeameter can be used for either constant head or slug tests. Local values of hydraulic conductivity are obtained by dividing the test result by a shape factor. Previously used shape factors have assumed that the packers are infinitely large. Such shape factors may lead to overestimates of hydraulic conductivity as they ignore

S. A. Mathias; A. P. Butler

2006-01-01

439

On the Hydraulics of Flowing Horizontal Wells  

Microsoft Academic Search

A flowing horizontal well is a special type of horizontal well that does not have pumping\\/injecting facility. The discharge rate of a flowing horizontal well is controlled by the hydraulic gradient between the aquifer and the well and it generally varies with time if the hydraulic head of the aquifer is transient. This type of well has been used in

A. Bian; H. Zhan

2003-01-01

440

Pressure variable orifice for hydraulic control valve  

NASA Technical Reports Server (NTRS)

Hydraulic valve absorbs impact energy generated in docking or joining of two large bodies by controlling energy release to avoid jarring shock. The area of exit porting presented to the hydraulic control fluid is directly proportional to the pressure acting on the fluid.

Ammerman, R. L.

1968-01-01

441

Institute of Hydraulics and Automation (IHA)  

NSDL National Science Digital Library

The Institute of Hydraulics and Automation, located at the University of Tampere in Finland, has a very active research program with many focus areas. Digital and water hydraulics, condition control, and virtual technologies are all investigated at the institute, and project descriptions in each of these areas are given on the site. Course descriptions and a research publications index are also available to visitors.

2008-03-13

442

SAR imagery of the Grand Banks (Newfoundland) pack ice pack and its relationship to surface features  

NASA Technical Reports Server (NTRS)

Synthetic Aperture Radar (SAR) data and aerial photographs were obtained over pack ice off the East Coast of Canada in March 1987 as part of the Labrador Ice Margin Experiment (LIMEX) pilot project. Examination of this data shows that although the pack ice off the Canadian East Coast appears essentially homogeneous to visible light imagery, two clearly defined zones of ice are apparent on C-band SAR imagery. To identify factors that create the zones seen on the radar image, aerial photographs were compared to the SAR imagery. Floe size data from the aerial photographs was compared to digital number values taken from SAR imagery of the same ice. The SAR data of the inner zone acquired three days apart over the melt period was also examined. The studies indicate that the radar response is governed by floe size and meltwater distribution.

Argus, S. D.; Carsey, F. D.

1988-01-01

443

14 CFR 35.43 - Propeller hydraulic components.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Propeller hydraulic components. 35.43 Section 35...and Inspections 35.43 Propeller hydraulic components. Applicants must show...that propeller components that contain hydraulic pressure and whose structural...

2010-01-01

444

49 CFR 570.55 - Hydraulic brake system.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Hydraulic brake system. 570.55 Section...Than 10,000 Pounds 570.55 Hydraulic brake system. The following requirements apply to vehicles with hydraulic brake systems. (a) Brake...

2010-10-01

445

7 CFR 2902.28 - Stationary equipment hydraulic fluids.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Stationary equipment hydraulic fluids. 2902.28 Section 2902...2902.28 Stationary equipment hydraulic fluids. (a) Definition. Fluids formulated for use in stationary hydraulic equipment systems that...

2010-01-01

446

Effective hydraulic conductivity of bounded, strongly heterogeneous porous media  

E-print Network

Effective hydraulic conductivity of bounded, strongly heterogeneous porous media Evangelos K of Arizona, Tucson Abstract. We develop analytical expressions for the effective hydraulic conductivity Ke boundaries. The log hydraulic conductivity Y forms a Gaussian, statistically homogeneous and anisotropic

Tartakovsky, Daniel M.

447

23 CFR 650.111 - Location hydraulic studies.  

Code of Federal Regulations, 2012 CFR

...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains 650.111 Location hydraulic studies....

2012-04-01

448

Scaling hydraulic properties of a macroporous soil Binayak P. Mohanty  

E-print Network

Scaling hydraulic properties of a macroporous soil Binayak P. Mohanty U.S. Salinity Laboratory, Riverside, California Abstract. Macroporous soils exhibit significant differences in their hydraulic properties for different pore domains. Multimodal hydraulic functions may be used to describe

Mohanty, Binayak P.

449

23 CFR 650.111 - Location hydraulic studies.  

Code of Federal Regulations, 2011 CFR

...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains 650.111 Location hydraulic studies....

2011-04-01

450

23 CFR 650.111 - Location hydraulic studies.  

Code of Federal Regulations, 2013 CFR

...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains 650.111 Location hydraulic studies....

2013-04-01

451

Soil Hydraulic Characteristics of a Small Southwest Oregon Watershed Following  

E-print Network

--------------------------------------------- Soil Hydraulic Characteristics of a Small Southwest by a high-intensity burn over areas of steep topography. The areal distribution of soil hydraulic of infiltration capacity, saturated hydraulic conductivity, and soil moisture characteristics. Also, measures

Standiford, Richard B.

452

7 CFR 2902.10 - Mobile equipment hydraulic fluids.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Mobile equipment hydraulic fluids. 2902...PROCUREMENT Designated Items 2902.10 Mobile equipment hydraulic fluids. (a) Definition...procurement preference for qualifying biobased mobile equipment hydraulic fluids. By...

2010-01-01

453

Hydraulic Permeability of Resorcinol-Formaldehyde Resin  

SciTech Connect

An ion exchange process using spherical resorcinol-formaldehyde (RF) resin is the baseline process for removing cesium from the dissolved salt solution in the high-level waste tanks at the Hanford Site, using large scale columns as part of the Waste Treatment Plant (WTP). The RF resin is also being evaluated for use in the proposed small column ion exchange (SCIX) system, which is an alternative treatment option at Hanford and at the Savannah River Site (SRS). A recirculating test loop with a small ion exchange column was used to measure the effect of oxygen uptake and radiation exposure on the permeability of a packed bed of the RF resin. The lab-scale column was designed to be prototypic of the proposed Hanford columns at the WTP. Although the test equipment was designed to model the Hanford ion exchange columns, the data on changes in the hydraulic permeability of the resin will also be valuable for determining potential pressure drops through the proposed SCIX system. The superficial fluid velocity in the lab-scale test (3.4-5.7 cm/s) was much higher than is planned for the full-scale Hanford columns to generate the maximum pressure drop expected in those columns (9.7 psig). The frictional drag from this high velocity produced forces on the resin in the lab-scale tests that matched the design basis of the full-scale Hanford column. Any changes in the resin caused by the radiation exposure and oxygen uptake were monitored by measuring the pressure drop through the lab-scale column and the physical properties of the resin. Three hydraulic test runs were completed, the first using fresh RF resin at 25 C, the second using irradiated resin at 25 C, and the third using irradiated resin at 45 C. A Hanford AP-101 simulant solution was recirculated through a test column containing 500 mL of Na-form RF resin. Known amounts of oxygen were introduced into the primary recirculation loop by saturating measured volumes of the simulant solution with oxygen and reintroducing the oxygenated simulant into the feed tank. The dissolved oxygen (DO) concentration of the recirculating simulant was monitored, and the amount of oxygen that reacted with the resin was determined from the change in the DO concentration of the recirculating simulant solution. Prior to hydraulic testing the resin for runs 2 and 3 was covered with the simulant solution and irradiated in a spent fuel element at the Oak Ridge National Laboratory High Flux Isotope Reactor (HFIR). Both batches of resin were irradiated to a total gamma dose of 177 Mrad, but the resin for run 2 reached a maximum temperature during irradiation of 51 C, while the resin for run 3 reached a temperature of 38 C. The different temperatures were the result of the operating status of HFIR at the time of the irradiation and were not part of the test plan; however, the results clearly show the impact of the higher-temperature exposure during irradiation. The flow rate and pressure drop data from the test loop runs show that irradiating the RF resin reduces both the void fraction and the permeability of the resin bed. The mechanism for the reduction in permeability is not clear because irradiation increases the particle size of the resin beads and makes them deform less under pressure. Microscopic examination of the resin beads shows that they are all smooth regular spheres and that irradiation or oxygen uptake did not change the shape of the beads. The resin reacts rapidly with DO in the simulant solution, and the reaction with oxygen reduces the permeability of a bed of new resin by about 10% but has less impact on the permeability of irradiated resin. Irradiation increases the toughness of the resin beads, probably by initiating cross-linking reactions in them. Oxygen uptake reduces the crush strength of both new and irradiated resin; however, the pressures that caused the beads to crush are much higher than would be expected during the operation of an ion exchange column. There was no visible evidence of broken beads in any of the resin samples taken from the test loop. Reaction with oxygen red

Taylor, Paul Allen [ORNL

2010-01-01

454

Hydraulic Geometry and Channel Roughness  

NSDL National Science Digital Library

In this field exercise, students measure channel cross sections in a rough alluvial and smooth bedrock-floored reach in a local stream. This exercise is hypothesis-driven. The hypothesis states that increasing roughness decreases average stream velocity, and so the depth and/or width must increase for the rougher bed. Working in groups, students use hand levels, tape measures, and surveying rods to document channel geometry. They then must reduce the data and plot it as distance-elevation on a chart. Finally, they analyze and compare the results to the predicted roughness-hydraulic geometry relation. Students learn simple surveying methods to collect field data. Students compare real world data to theoretical predictions. Students gain insight into how bank and bed roughness influences water flow, and thus can also influence flood heights. Designed for a geomorphology course Integrates geomorphology into a core course in geology Designed for an introductory geology course Uses geomorphology to solve problems in other fields

Hasbargen, Les

455

Thermal hydraulics development for CASL  

SciTech Connect

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

Lowrie, Robert B [Los Alamos National Laboratory

2010-12-07

456

CONCRETE OPTIMISATION WITH REGARD TO PACKING DENSITY AND RHEOLOGY  

E-print Network

CONCRETE OPTIMISATION WITH REGARD TO PACKING DENSITY AND RHEOLOGY François de Larrard LCPC Centre/organizers): .............. Keywords: packing density, rheology, grading curve, optimisation, self-compacting concrete, roller-compacted concrete. Author contacts Authors E-Mail Fax Postal address LCPC Centre de Nantes François de Larrard

Paris-Sud XI, Université de

457

CIRCLE PACKINGS ON SURFACES WITH PROJECTIVE STRUCTURES AND UNIFORMIZATION  

E-print Network

CIRCLE PACKINGS ON SURFACES WITH PROJECTIVE STRUCTURES AND UNIFORMIZATION Sadayoshi Kojima, Shigeru be identified with the set of all pairs of a projective structure and a circle packing on it with nerve isotopic to , is homeomorphic to R6g-6 , and moreover that the forgetting map of C to the space of projective structures

Tan, Ser Peow

458

CIRCLE PACKINGS ON SURFACES WITH PROJECTIVE STRUCTURES AND UNIFORMIZATION  

E-print Network

CIRCLE PACKINGS ON SURFACES WITH PROJECTIVE STRUCTURES AND UNIFORMIZATION Sadayoshi Kojima, Shigeru be identified with the set of all pairs of a projective structure and a circle packing on it with nerve isotopic to # , is homeomorphic to R 6g-6 , and moreover that the forgetting map of C # to the space of projective structures

Tan, Ser Peow

459

The packing and compaction dynamics of granular polymers  

NASA Astrophysics Data System (ADS)

While the packing of hard spheres has been the subject of intense research, the packing of objects with reduced symmetries is far less well-studied, both experimentally and theoretically. Here, we report an experimental study on the packing of a granular polymer analogue --- chains of hollow, spherical brass beads, 1.9 mm in diameter, ranging in length from a 1 to 42 700 beads per chain. In particular, we systematically measure the density ? of the bead-chain pack as a function of the number of beads per chain M (i.e. the molecular weight of the granular polymer). The density decreases from the random close packed density ?RCP 0.64 for single beads to an asymptotic density ?? 0.39 in the limit of very long chains; the form of the density fall-off is rather slow, the effect is noticeable even when M is much larger than the chain persistence length. In terms of dynamics, the compaction of bead-chain packs appears to obey the same logarithmic relaxation form found in the compaction of single bead packs [1], but with a puzzling, M-dependent sensitivity to initial conditions. We shall discuss these results in the context of, and attempt to make connections to, the packing of single hard spheres on one hand and the physics of polymer melts on the other. [1] J. B. Knight et al., Phys. Rev. E 51, 3957 - 3963 (1995).

Zou, Ling-Nan; Cheng, Xiang; Jaeger, Heinrich; Nagel, Sidney

2007-03-01

460

Metallic witness packs for behind-armour debris characterisation  

Microsoft Academic Search

For the experimental characterisation of behind-armour debris so-called metallic witness packs can be used. A metallic witness pack consists of an array of metallic plates interspaced by polystyrene foam sheets. To quantify the fragment mass and velocity from the corresponding hole area and position in the individual witness plates, perforation threshold curves must be available to provide the ballistic limit

J. L. Verolme; M. Szymczak; J. P. F. Broos

1999-01-01

461

Biological phenol removal using suspended growth and packed bed reactors  

Microsoft Academic Search

Phenol removal was studied using batch cultures of free suspended cells and attached growth processes. Indigenous bacteria from olive pulp were enriched and used as inoculum for the filter and a suspended-growth flask reactor. A pilot-scale packed bed reactor was constructed and operated for biological phenol removal from industrial wastewater. The packed bed reactor was found to be more resistant

G. Tziotzios; M. Teliou; V. Kaltsouni; G. Lyberatos; D. V. Vayenas

2005-01-01

462

Cell packing influences planar cell polarity signaling , Keith Amonlirdvimanb,1  

E-print Network

Cell packing influences planar cell polarity signaling Dali Maa,1 , Keith Amonlirdvimanb,1 , Robin wing, a combination of cell geometry and nonautonomous signaling at clone boundaries determines with a local feedback mechanism to overcome irregu- larities in cell packing geometry during PCP signaling

Abate, Alessandro

463

Paired Science: A Resource Pack for Parents and Children.  

ERIC Educational Resources Information Center

This pack of resource materials is designed for students in Scotland, ages 5-7, to be done with their parents at home or with another student in school. Forty-five activity sheets cover 7 different areas of science: Air, Magnets, Moving Things, Light, Heat, Myself and Water. The pack also includes a leaflet for parent or peer tutors, lists of

Croft, Susan; Topping, Keith

464

Scheduling Mixed Tasks with Deadlines in Grids Using Bin Packing  

Microsoft Academic Search

This paper addresses the problem of scheduling independent tasks with different priorities and deadline constraints in computational grids. The problem is first formulated as a bin packing problem. We propose a heuristic algorithm named Residual Capacity Maximization Scheduling (RCMS), which integrates the ideas of a classical bin packing algorithm (Best Fit) and a mixed integer quadratic programming modeling approach. RCMS

Cong Liu; Sanjeev Baskiyar

2008-01-01

465

Perfusion chromatography characterization of column packings for chromatography of proteins  

Microsoft Academic Search

A Van Deemter equation modeling columns packed with spherical monodisperse perfusive media was utilized to calculate the predicted values of the effective pore diffusivity (Dp) and split ratio (?) of columns packed with POROS and Oligo R3 media. The validity of the model was established by calculating consistent values of Dp and ? for lysozyme, ?-chymotrypsinogen A and IgG using

Mark McCoy; Krishna Kalghatgi; Fred E. Regnier; Noubar Afeyan

1996-01-01

466

Packed bed reactor for photochemical .sup.196 Hg isotope separation  

DOEpatents

Straight tubes and randomly oriented pieces of tubing having been employed in a photochemical mercury enrichment reactor and have been found to improve the enrichment factor (E) and utilization (U) compared to a non-packed reactor. One preferred embodiment of this system uses a moving bed (via gravity) for random packing.

Grossman, Mark W. (Belmont, MA); Speer, Richard (Reading, MA)

1992-01-01

467

Porosity distribution in random packed columns by gamma ray tomography  

Microsoft Academic Search

Gamma ray tomography experiments have been carried out to detect any spatial patterns in the porosity in a 0.6 m diameter packed column. Three different sizes of stainless steel Pall rings (16, 25 and 38 mm) have been examined. The primary objective is to detect spatial patterns and statistical information on porosity variation in packed distillation columns. Such data are

Zhongcheng Wang; Artin Afacan; K. Nandakumar; Karl T. Chuang

2001-01-01

468

Backfilling with Lookahead to Optimize the Packing of Parallel Jobs  

E-print Network

Backfilling with Lookahead to Optimize the Packing of Parallel Jobs Edi Shmueli Department@cs.huji.ac.il Abstract The utilization of parallel computers depends on how jobs are packed together: if the jobs may conflict with goals of fairness or even progress for all jobs. The common solution is to use

Feitelson, Dror

469

Heat Transfer Studies on Packed Bed Using Non Newtonian Fluid  

Microsoft Academic Search

This project aims to study and compare the heat transfer characteristics for Countercurrent flow and Parallel Flow through Packed Bed by determining the overall heat transfer coefficient, effectiveness, cold side efficiency and hot side efficiency for water-water system and Carboxymethylcellulose (CMC)-water system with various compositions on volume basis. In Packed Bed, the inlet temperatures of both hot and cold fluids

D. Priyadharisani; M. Thirumarimurugan; T. Kannadasan

2011-01-01

470

Complexity in Surfaces of Densest Packings for Families of Polyhedra  

NASA Astrophysics Data System (ADS)

Packings of hard polyhedra have been studied for centuries due to their mathematical aesthetic and more recently for their applications in fields such as nanoscience, granular and colloidal matter, and biology. In all these fields, particle shape is important for structure and properties, especially upon crowding. Here, we explore packing as a function of shape. By combining simulations and analytic calculations, we study three two-parameter families of hard polyhedra and report an extensive and systematic analysis of the densest known packings of more than 55 000 convex shapes. The three families have the symmetries of triangle groups (icosahedral, octahedral, tetrahedral) and interpolate between various symmetric solids (Platonic, Archimedean, Catalan). We find optimal (maximum) packing-density surfaces that reveal unexpected richness and complexity, containing as many as 132 different structures within a single family. Our results demonstrate the importance of thinking about shape not as a static property of an object, in the context of packings, but rather as but one point in a higher-dimensional shape space whose neighbors in that space may have identical or markedly different packings. Finally, we present and interpret our packing results in a consistent and generally applicable way by proposing a method to distinguish regions of packings and classify types of transitions between them.

Chen, Elizabeth R.; Klotsa, Daphne; Engel, Michael; Damasceno, Pablo F.; Glotzer, Sharon C.

2014-01-01

471

Packing variations on a ripple of nearly monodisperse dry sand  

Microsoft Academic Search

Dielectric measurements reveal that bulk density on the surface of recently mobilized dry ripples of a nearly monodisperse desert sand varies from the random jammed packing at troughs to the minimum value for a stable packing at crests, suggesting that active ripples are relatively loose structures moving above a more consolidated substratum. Although the wind-driven evolution of static pressure on

M. Y. Louge; A. Valance; A. Ould el-Moctar; P. Dupont

2010-01-01

472

UPGRADING MEAT PACKING FACILITIES TO REDUCE POLLUTION. WASTE TREATMENT  

EPA Science Inventory

;Contents: Micro-organisms and their role in waste treatment; Waste loads from the meat packing industry; Procedures in the planning, design, and construction of a wastewater-treatment system; Wastewater-treatment methods for the meat packing industry; Operation and maintenance o...

473

Hydraulic fracturing of jointed formations  

SciTech Connect

Measured by volume, North America's largest hydraulic fracturing operations have been conducted at Fenton Hill, New Mexico to create geothermal energy reservoirs. In the largest operation 21,000 m/sup 3/ of water were injected into jointed granitic rock at a depth of 3.5 km. Microearthquakes induced by this injection were measured with geophones placed in five wells drilled into, or very close, to the reservoir, as well as 11 surface seismometers. The large volume of rock over which the microearthquakes were distributed indicates a mechanism of hydraulic stimulation which is at odds with conventional fracturing theory, which predicts failure along a plane which is perpendicular to the least compressive earth stress. A coupled rock mechanics/fluid flow model provides much of the explanation. Shear slippage along pre-existing joints in the rock is more easily induced than conventional tensile failure, particularly when the difference between minimum and maximum earth stresses is large and the joints are oriented at angles between 30 and 60 degrees to the principal earth stresses, and a low viscosity fluid like water is injected. Shear slippage results in local redistribution of stresses, which allows a branching, or dendritic, stimulation pattern to evolve, in agreement with the patterns of microearthquake locations. These results are qualitatively similar to the controversial process known as ''Kiel'' fracturing, in which sequential injections and shut-ins are repeated to create dendritic fractures for enhanced oil and gas recovery. However, we believe that the explanation is shear slippage of pre-existing joints and stress redistribution, not proppant bridging and fluid blocking as suggested by Kiel. 15 refs., 10 figs.

Murphy, H.D.; Fehler, M.C.

1986-01-01

474

Evolving Design Rules for the Inverse Granular Packing Problem  

E-print Network

If a collection of identical particles is poured into a container, different shapes will fill to different densities. But what is the shape that fills a container as close as possible to a pre-specified, desired density? We demonstrate a solution to this inverse-packing problem by framing it in the context of artificial evolution. By representing shapes as bonded spheres, we show how shapes may be mutated, simulated, and selected to produce particularly dense or loose packing aggregates, both with and without friction. Moreover, we show how motifs emerge linking these shapes together. The result is a set of design rules that function as an effective solution to the inverse packing problem for given packing procedures and boundary conditions. Finally, we show that these results are verified by experiments on 3D-printed prototypes used to make packings in the real world.

Marc Z. Miskin; Heinrich M. Jaeger

2014-03-17

475

Statistical theory of correlations in random packings of hard particles  

NASA Astrophysics Data System (ADS)

A random packing of hard particles represents a fundamental model for granular matter. Despite its importance, analytical modeling of random packings remains difficult due to the existence of strong correlations which preclude the development of a simple theory. Here, we take inspiration from liquid theories for the n-particle angular correlation function to develop a formalism of random packings of hard particles from the bottom up. A progressive expansion into a shell of particles converges in the large layer limit under a Kirkwood-like approximation of higher-order correlations. We apply the formalism to hard disks and predict the density of two-dimensional random close packing (RCP), ?rcp=0.850.01, and random loose packing (RLP), ?rlp=0.670.01. Our theory also predicts a phase diagram and angular correlation functions that are in good agreement with experimental and numerical data.

Jin, Yuliang; Puckett, James G.; Makse, Hernn A.

2014-05-01

476

Random close packing of disks and spheres in confined geometries  

NASA Astrophysics Data System (ADS)

Studies of random close packing of spheres have advanced our knowledge about the structure of systems such as liquids, glasses, emulsions, granular media, and amorphous solids. In confined geometries, the structural properties of random-packed systems will change. To understand these changes, we study random close packing in finite-sized confined systems, in both two and three dimensions. Each packing consists of a 50-50 binary mixture with particle size ratio of 1.4. The presence of confining walls significantly lowers the overall maximum area fraction (or volume fraction in three dimensions). A simple model is presented, which quantifies the reduction in packing due to wall-induced structure. This wall-induced structure decays rapidly away from the wall, with characteristic length scales comparable to the small particle diameter.

Desmond, Kenneth W.; Weeks, Eric R.

2009-11-01

477

A critical review of dispersion in packed beds  

NASA Astrophysics Data System (ADS)

The phenomenon of dispersion (transverse and longitudinal) in packed beds is summarized and reviewed for a great deal of information from the literature. Dispersion plays an important part, for example, in contaminant transport in ground water flows, in miscible displacement of oil and gas and in reactant and product transport in packed bed reactors. There are several variables that must be considered, in the analysis of dispersion in packed beds, like the length of the packed column, viscosity and density of the fluid, ratio of column diameter to particle diameter, ratio of column length to particle diameter, particle size distribution, particle shape, effect of fluid velocity and effect of temperature (or Schmidt number). Empirical correlations are presented for the prediction of the dispersion coefficients ( D T and D L) over the entire range of practical values of Sc and Pem, and works on transverse and longitudinal dispersion of non-Newtonian fluids in packed beds are also considered.

Delgado, J. M. P. Q.

2006-02-01

478

Statistical theory of correlations in random packings of hard particles  

E-print Network

A random packing of hard particles represents a fundamental model for granular matter. Despite its importance, analytical modeling of random packings remains difficult due to the existence of strong correlations which preclude the development of a simple theory. Here, we take inspiration from liquid theories for the $n$-particle angular correlation function to develop a formalism of random packings of hard particles from the bottom-up. A progressive expansion into a shell of particles converges in the large layer limit under a Kirkwood-like approximation of higher-order correlations. We apply the formalism to hard disks and predict the density of two-dimensional random close packing (RCP), $\\phi_{\\rm rcp} = 0.85\\pm0.01$, and random loose packing (RLP), $\\phi_{\\rm rlp} = 0.67\\pm0.01$. Our theory also predicts a phase diagram and angular correlation functions that are in good agreement with experimental and numerical data.

Yuliang Jin; James G. Puckett; Hernan A. Makse

2014-05-10

479

Single-well interference slug tests to assess the vertical hydraulic conductivity of unconsolidated aquifers  

NASA Astrophysics Data System (ADS)

SummaryMeaningful understanding of flow and solute transport in general requires the knowledge of hydraulic conductivity and its anisotropy. Various field methods allow the measurement of the horizontal component (Kh), but vertical hydraulic conductivity (Kv) is rarely measured, for lack of practical field tests. This paper proposes vertical interference slug tests, an adaptation of inter-well interference slug tests to a single well, for the efficient field measurement of Kv. The test is carried out in a single well between a stress and an observation interval that are vertically isolated with a three-packer assembly. An instantaneous pressure pulse is induced in the stress interval and resulting drawdowns are recorded in both the stress and the observation intervals. In a proof-of-concept field study, 12 vertical interference tests were carried out sequentially along a fully-screened well across a moderately heterogeneous and highly anisotropic aquifer made up of littoral silts and sands. A direct-push method was used to install the well, which was completed without sand-pack to allow the natural collapse of sediments in the thin annular space around the screen. Direct-push wells allow the measurement of in situ hydraulic properties of sediments and minimize well construction interferences with hydraulic tests. Drawdowns measured in stress and observation intervals of multiple tests were simultaneously inverted numerically to reconstruct heterogeneous profiles of Kh, hydraulic conductivity anisotropy (Kv/Kh), and specific storage (Ss). Results were validated by comparison of observed versus predicted drawdowns and with field and laboratory measurements of Kh and Kv made along the tested well. Results indicate that the profile of Kv values obtained with vertical interference slug tests follows a similar pattern with depth than the profile with lab measurements made with a permeameter on soil samples collected in the same intervals as the interference tests, which demonstrates that vertical interference slug tests could provide an efficient method for the field measurement of well-scale Kv values.

Paradis, Daniel; Lefebvre, Ren

2013-01-01

480

Dependence of sintering temperature of BaTiO3 pellets on NOx removal in a packed-bed plasma reactor  

Microsoft Academic Search

The NOx removal from air streams has been investigated using a packed-bed plasma reactor. In this study, BaTiO3 pellets are prepared at various sintering temperatures by the authors and the effect of sintering temperature of the pellets on NOx removal are studied experimentally. The packed-bed plasma is generated by a 25 kHz AC high voltage power supply. Experiments are carried

Toshikazu Ohkubo; Toshiyuki Kawasaki; Seiji Kanazawa; Yukiharu Nomoto

1998-01-01

481

The 25 kWe solar thermal Stirling hydraulic engine system: Conceptual design  

NASA Technical Reports Server (NTRS)

The conceptual design and analysis of a solar thermal free-piston Stirling hydraulic engine system designed to deliver 25 kWe when coupled to a 11 meter test bed concentrator is documented. A manufacturing cost assessment for 10,000 units per year was made. The design meets all program objectives including a 60,000 hr design life, dynamic balancing, fully automated control, more than 33.3 percent overall system efficiency, properly conditioned power, maximum utilization of annualized insolation, and projected production costs. The system incorporates a simple, rugged, reliable pool boiler reflux heat pipe to transfer heat from the solar receiver to the Stirling engine. The free-piston engine produces high pressure hydraulic flow which powers a commercial hydraulic motor that, in turn, drives a commercial rotary induction generator. The Stirling hydraulic engine uses hermetic bellows seals to separate helium working gas from hydraulic fluid which provides hydrodynamic lubrication to all moving parts. Maximum utilization of highly refined, field proven commercial components for electric power generation minimizes development cost and risk.

White, Maurice; Emigh, Grant; Noble, Jack; Riggle, Peter; Sorenson, Torvald

1988-01-01

482

Consolidation of the packing material in chromatographic columns under dynamic axial compression IV. Mechanical properties of some packing materials  

Microsoft Academic Search

Dynamic axial compression columns were packed with three C18 silica materials used as statinalry phases in preparative chromatography, one made of irregular and two of spherical particles. Measurements of column lenght vs. time and axial compression pressure, obtained for several columns, have been previously reported. These results are discussed here in terms of packing density, internal porosity, and external porosity,

Brett J. Stanley; Matilal Sarker; Georges Guiochon

1996-01-01

483

Mass-transfer performance of rotating packed beds equipped with blade packings in VOCs absorption into water  

Microsoft Academic Search

This work examined the mass transfer of the rotating packed bed (RPB) equipped with blade packings using VOCs absorption. Ethanol, acetone and ethyl acetate were used as the model VOCs herein. The overall volumetric gas-side mass-transfer coefficient (KGa) for three VOCs absorption was observed to increase with the rotor speed, the gas flow rate and the liquid flow rate. Moreover,

Chia-Chang Lin; Kuo-Shin Chien

2008-01-01

484

Development of Hydraulic Friction Brake for Railway Rolling Stock  

NASA Astrophysics Data System (ADS)

In this study, a novel hydraulic brake system is proposed in order to increase the reliability of railway brake systems. The reason hydraulic brake systems have not been taken up as a practical railway brake system until now is that the brake pressure control valve inherently has internal leakage and this causes insufficient fail-safe function. Accordingly, We focus on the development of a hydraulic brake pressure control valve (BPC valve) in this study. By virtue of adopting poppet elements in the valve, the braking force is maintained without internal leakage even when the electric power supply fails. The developed BPC valve includes a built-in pressure feedback mechanism and it enables the pressure control function to be maintained when the pressure transducer is broken. The operating principle and wear compensation methods for poppet elements are also examined in this study. The experimental results verify the linearity of static behavior, the stability, and the performance of the valve in maintaining output pressure.

Chenvisuwat, Thum; Park, Sung-Hwan; Kitagawa, Ato

485

Vapor diffusion in partially saturated packed beds  

SciTech Connect

The objective of this experimental and numerical study is to quantify the vapor diffusion enhancement factor resulting from pore-level evaporation/condensation in porous media subjected to a temperature gradient. In an earlier paper the enhancement factor {beta}, extracted from nonisothermal diffusion experiments, was shown to increase to approximately 1.0, which is equivalent to the free space diffusion coefficient, as average saturation in the packed bed increases from 0 to 0.2. The results of a drying experiment involving an initially partially saturated bed are presented in this paper. Numerical simulations of the nonisothermal diffusion and drying experiments using the TOUGH2 code were performed. The predicted vapor fluxes in both transient and quasi-steady simulations for the nonisothermal diffusion experiment are in good agreement with the experimental results when the experimentally determined enhancement factor is incorporated into the code. Simulated saturation profiles for drying are in qualitative agreement with experimental results. In both simulations the discrepancy between the predicted and observed saturation distributions may be the result of capillary hysteresis which is not included in the TOUGH2 code. Comparison between the experiments and simulations supports the existence of the enhanced vapor diffusion mechanism and indicates that the enhancement factor ranges from 0.3 to 1.0 depending on the moisture content.

Gu, L.; Ho, C.K.; Plumb, O.A.; Webb, S.W.

1999-07-01

486

Automated packing systems: review of industrial implementations  

NASA Astrophysics Data System (ADS)

A rich theoretical background to the problems that occur in the automation of material handling can be found in operations research, production engineering, systems engineering and automation, more specifically machine vision, literature. This work has contributed towards the design of intelligent handling systems. This paper will review the application of these automated material handling and packing techniques to industrial problems. The discussion will also highlight the systems integration issues involved in these applications. An outline of one such industrial application, the automated placement of shape templates on to leather hides, is also discussed. The purpose of this system is to arrange shape templates on a leather hide in an efficient manner, so as to minimize the leather waste, before they are automatically cut from the hide. These pieces are used in the furniture and car manufacturing industries for the upholstery of high quality leather chairs and car seats. Currently this type of operation is semi-automated. The paper will outline the problems involved in the full automation of such a procedure.

Whelan, Paul F.; Batchelor, Bruce G.

1993-08-01

487

Granular packings: nonlinear elasticity, sound propagation, and collective relaxation dynamics.  

PubMed

Experiments on isotropic compression of a granular assembly of spheres show that the shear and bulk moduli vary with the confining pressure faster than the 1/3 power law predicted by Hertz-Mindlin effective medium theories of contact elasticity. Moreover, the ratio between the moduli is found to be larger than the prediction of the elastic theory by a constant value. The understanding of these discrepancies has been a long-standing question in the field of granular matter. Here we perform a test of the applicability of elasticity theory to granular materials. We perform sound propagation experiments, numerical simulations, and theoretical studies to understand the elastic response of a deforming granular assembly of soft spheres under isotropic loading. Our results for the behavior of the elastic moduli of the system agree very well with experiments. We show that the elasticity partially describes the experimental and numerical results for a system under compressional loads. However, it drastically fails for systems under shear perturbations, particularly for packings without tangential forces and friction. Our work indicates that a correct treatment should include not only the purely elastic response but also collective relaxation mechanisms related to structural disorder and nonaffine motion of grains. PMID:15697350

Makse, Hernn A; Gland, Nicolas; Johnson, David L; Schwartz, Lawrence

2004-12-01

488

Bubble visualization in a simulated hydraulic jump  

E-print Network

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

Witt, Adam; Shen, Lian

2013-01-01

489

Real-time and post-frac' 3-D analysis of hydraulic fracture treatments in geothermal reservoirs  

SciTech Connect

Economic power production from Hot Dry Rock (HDR) requires the establishment of an efficient circulation system between wellbores in reservoir rock with extremely low matrix permeability. Hydraulic fracturing is employed to establish the necessary circulation system. Hydraulic fracturing has also been performed to increase production from hydrothermal reservoirs by enhancing the communication with the reservoir's natural fracture system. Optimal implementation of these hydraulic fracturing applications, as with any engineering application, requires the use of credible physical models and the reconciliation of the physical models with treatment data gathered in the field. Analysis of the collected data has shown that 2-D models and 'conventional' 3-D models of the hydraulic fracturing process apply very poorly to hydraulic fracturing in geothermal reservoirs. Engineering decisions based on these more 'conventional' fracture modeling techniques lead to serious errors in predicting the performance of hydraulic fracture treatments. These errors can lead to inappropriate fracture treatment design as well as grave errors in well placement for hydrothermal reservoirs or HDR reservoirs. This paper outlines the reasons why conventional modeling approaches fall short, and what types of physical models are needed to credibly estimate created hydraulic fracture geometry. The methodology of analyzing actual measured fracture treatment data and matching the observed net fracturing pressure (in realtime as well as after the treatment) is demonstrated at two separate field sites. Results from an extensive Acoustic Emission (AE) fracture diagnostic survey are also presented for the first case study aS an independent measure of the actual created hydraulic fracture geometry.

Wright, C.A.; Tanigawa, J.J.; Hyodo, Masami; Takasugi, Shinji

1994-01-20

490

The circular internal hydraulic jump  

NASA Astrophysics Data System (ADS)

Circular hydraulic jumps are familiar in single layers. Here we report the discovery of similar jumps in two-layer flows. A thin jet of fluid impinging vertically onto a rigid horizontal plane surface submerged in a deep layer of less-dense miscible fluid spreads radially, and a near-circular internal jump forms within a few centimetres from the point of impact with the plane surface. A jump is similarly formed as a jet of relatively less-dense fluid rises to the surface of a deep layer of fluid, but it appears less stable or permanent in form. Several experiments are made to examine the case of a downward jet onto a horizontal plate, the base of a square or circular container. The inlet Reynolds numbers, Re, of the jet range from 112 to 1790. Initially jumps have an undular, laminar form with typically 2-4 stationary waves on the interface between the dense and less-dense layers but, as the depth of the dense layer beyond the jump increases, the transitions become more abrupt and turbulent, resulting in mixing between the two layers. During the transition to a turbulent regime, single and sometimes moving multiple cusps are observed around the periphery of jumps. A semi-empirical model is devised that relates the parameters of the laboratory experiment, i.e. flow rate, inlet nozzle radius, kinematic viscosity and reduced gravity, to the layer depth beyond the jump and the radius at which an undular jump occurs. The experiments imply that surface tension is not an essential ingredient in the formation of circular hydraulic jumps and demonstrate that stationary jumps can exist in stratified shear flows which can be represented as two discrete layers. No stationary circular undular jumps are found, however, in the case of a downward jet of dense fluid when the overlying, less-dense, fluid is stratified, but a stationary turbulent transition is observed. This has implications for the existence of stationary jumps in continuously stratified geophysical flows: results based on two-layer models may be misleading. It is shown that the Froude number at which a transition of finite width occurs in a radially diverging flow may be less than unity.

Thorpe, S. A.; Kavcic, I.

491

Hydraulic Fracturing and the Environment  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

492

Wellbore pressure differential control for gravel pack screen  

SciTech Connect

A method is described for minimizing cross-flow of fluid in a wellbore in an earth formation and fitted with a gravel packing and an auger-type gravel pack screen, comprising the steps of: providing an auger-type gravel pack screen having a generally tubular liner member defining a space therewithin; providing a quantity of wellbore fluid loss control material comprising a graded particulate salt disposed in said space which will provide a substantially impermeable barrier to the flow of fluid out of said space through said liner into said gravel packing and said earth formation; filling at least a portion of said space with said material; installing said screen in said gravel packing; removing said material from said space after installation of said screen in said gravel packing by entraining said material in a carrier fluid while allowing at least some of said material to flow out of said space through said screen to form a filter cake on at least one of said gravel packing and said earth formation to minimize said cross-flow of fluid into said earth formation.

Cornette, H.M.

1993-08-10

493

Influence of Particle Size Distribution on Random Close Packing  

E-print Network

The densest amorphous packing of rigid particles is known as random close packing. It has long been appreciated that higher densities are achieved by using collections of particles with a variety of sizes. The variety of sizes is often quantified by the polydispersity of the particle size distribution: the standard deviation of the radius divided by the mean radius. Several prior studies quantified the increase of the packing density as a function of polydispersity. Of course, a particle size distribution is also characterized by its skewness, kurtosis, and higher moments, but the influence of these parameters has not been carefully quantified before. In this work, we numerically generate many packings with different particle radii distributions, varying polydispersity and skewness independently of one another. We find two significant results. First, the skewness can have a significant effect on the packing density and in some cases can have a larger effect than polydispersity. Second, the packing fraction is relatively insensitive to the value of the kurtosis. We present a simple empirical formula for the value of the random close packing density as a function of polydispersity and skewness.

Kenneth W. Desmond; Eric R. Weeks

2013-03-19

494

Packing and self-assembly of truncated triangular bipyramids  

NASA Astrophysics Data System (ADS)

Motivated by breakthroughs in the synthesis of faceted nano- and colloidal particles, as well as theoretical and computational studies of their packings, we investigate a family of truncated triangular bipyramids. We report dense periodic packings with small unit cells that were obtained via numerical and analytical optimization. The maximal packing fraction ?max changes continuously with the truncation parameter t. Eight distinct packings are identified based on discontinuities in the first and second derivatives of ?max(t). These packings differ in the number of particles in the fundamental domain (unit cell) and the type of contacts between the particles. In particular, we report two packings with four particles in the unit cell for which both ?max(t) and ?max'(t) are continuous and the discontinuity occurs in the second derivative only. In the self-assembly simulations that we perform for larger boxes with 2048 particles, only one out of eight packings is found to assemble. In addition, the degenerate quasicrystal reported previously for triangular bipyramids without truncation [Haji-Akbari , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.215702 107, 215702 (2011)] assembles for truncations as high as 0.45. The self-assembly propensities for the structures formed in the thermodynamic limit are explained using the isoperimetric quotient of the particles and the coordination number in the disordered fluid and in the assembled structure.

Haji-Akbari, Amir; Chen, Elizabeth R.; Engel, Michael; Glotzer, Sharon C.

2013-07-01

495

Packing and self-assembly of truncated triangular bipyramids.  

PubMed

Motivated by breakthroughs in the synthesis of faceted nano- and colloidal particles, as well as theoretical and computational studies of their packings, we investigate a family of truncated triangular bipyramids. We report dense periodic packings with small unit cells that were obtained via numerical and analytical optimization. The maximal packing fraction ?(max) changes continuously with the truncation parameter t. Eight distinct packings are identified based on discontinuities in the first and second derivatives of ?(max)(t). These packings differ in the number of particles in the fundamental domain (unit cell) and the type of contacts between the particles. In particular, we report two packings with four particles in the unit cell for which both ?(max)(t) and ?(max)'(t) are continuous and the discontinuity occurs in the second derivative only. In the self-assembly simulations that we perform for larger boxes with 2048 particles, only one out of eight packings is found to assemble. In addition, the degenerate quasicrystal reported previously for triangular bipyramids without truncation [Haji-Akbari et al., Phys. Rev. Lett. 107, 215702 (2011)] assembles for truncations as high as 0.45. The self-assembly propensities for the structures formed in the thermodynamic limit are explained using the isoperimetric quotient of the particles and the coordination number in the disordered fluid and in the assembled structure. PMID:23944434

Haji-Akbari, Amir; Chen, Elizabeth R; Engel, Michael; Glotzer, Sharon C

2013-07-01

496

Epitaxial growth of ordered and disordered granular sphere packings  

NASA Astrophysics Data System (ADS)

We demonstrate that epitaxy can be used to obtain a wide range of ordered to disordered granular packings by simply changing the deposition flux. We show that a defect-free face-centered-cubic (fcc) monocrystal can be obtained by depositing athermal granular spheres randomly into a container with a templated surface in a gravitational field without direct manipulation. This packing corresponds to the maximum sphere packing fraction and is obtained when the substrate is templated corresponding to the (100) plane of a fcc crystal and the container side is an integer multiple of the sphere diameter. We find that the maximum sphere packing is obtained when the deposited grains come to rest, one at a time, without damaging the substrate. A transition to a disordered packing is observed when the flux is increased. Using micro x-ray computed tomography, we find that defects nucleate at the boundaries of the container in which the packing is grown as grains cooperatively come to rest above their local potential minimum. This leads to a transition from ordered to disordered loose packings that grow in the form of an inverted cone, with the apex located at the defect nucleation site. We capture the observed decrease in order using a minimal model in which a defect leads to growth of further defects in the neighboring sites in the layer above with a probability that increases with the deposition flux.

Panaitescu, Andreea; Kudrolli, Arshad

2014-09-01

497

Linear hydraulic drive system for a Stirling engine  

SciTech Connect

A hydraulic drive system operating from the periodic pressure wave produced by a Stirling engine along a first axis thereof and effecting transfer of power from the Stirling engine to a load apparatus therefor and wherein the movable, or working member of the load apparatus is reciprocatingly driven along an axis substantially at right angles to the first axis to achieve an arrangement of a Stirling engine and load apparatus assembly which is much shorter and the components of the load apparatus more readily accessible. 2 figs.

Walsh, M.M.

1984-02-21

498

Linear hydraulic drive system for a Stirling engine  

DOEpatents

A hydraulic drive system operating from the periodic pressure wave produced by a Stirling engine along a first axis thereof and effecting transfer of power from the Stirling engine to a load apparatus therefor and wherein the movable, or working member of the load apparatus is reciprocatingly driven along an axis substantially at right angles to the first axis to achieve an arrangement of a Stirling engine and load apparatus assembly which is much shorter and the components of the load apparatus more readily accessible.

Walsh, Michael M. (Schenectady, NY)

1984-02-21

499

The influence of topology on hydraulic conductivity in a sand-and-gravel aquifer.  

PubMed

A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand-and-gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts. Geophysical logs and flowmeter/pumping measurements were obtained to estimate vertical profiles of porosity phi, hydraulic conductivity K, temperature, and bulk electrical conductivity under background, freshwater conditions. Saline-tracer fluid was then injected into the well for 2 h and its radial migration into the surrounding deposits was monitored by recording an electromagnetic-induction log every 10 min. The field data are analyzed and interpreted primarily through the use of Archie's (1942) law to investigate the role of topological factors such as pore geometry and connectivity, and grain size and packing configuration in regulating fluid flow through these coarse-grained materials. The logs reveal no significant correlation between K and phi, and imply that groundwater models that link these two properties may not be useful at this site. Rather, it is the distribution and connectivity of the fluid phase as defined by formation factor F, cementation index m, and tortuosity alpha that primarily control the hydraulic conductivity. Results show that F correlates well with K, thereby indicating that induction logs provide qualitative information on the distribution of hydraulic conductivity. A comparison of alpha, which incorporates porosity data, with K produces only a slightly better correlation and further emphasizes the weak influence of the bulk value of varphi on K. PMID:19878327

Morin, Roger H; LeBlanc, Denis R; Troutman, Brent M

2010-01-01

500

When do Jammed Particulate Packings have a Linear Regime?  

E-print Network

Packings of frictionless athermal particles that interact only when they overlap experience a jamming transition as a function of packing density. Such packings provide the foundation for the theory of jamming. This theory rests on the observation that, despite the multitude of disordered configurations, the mechanical response to linear order depends only on the distance to the transition. We investigate the validity and utility of such measurements that invoke the harmonic approximation, and show that there is a well-defined linear regime in the thermodynamic limit.

Carl P. Goodrich; Andrea J. Liu; Sidney R. Nagel

2014-02-25