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1

Characteristics of a confined jet thrust vector control nozzle  

Microsoft Academic Search

A study of confined jet thrust vector control (CJTVC) is presented. By isolating an area of flow separation within the body of a nozzle, CJTVC has the advantage over other thrust vector controls using secondary injection (SI) in that it can operate independent of altitude. This makes it ideal for applications in small missiles and spacecraft attitude control. In this

A. J. Porzio

1984-01-01

2

Experimental Evaluation of Design Variables for Two-Dimensional Confined Jet Thrust Vector Control Nozzles.  

National Technical Information Service (NTIS)

An experimental study of the axial and vectoring performance of two - dimensional (2-D) confined jet thrust vector control (CJTVC) nozzles was performed. The effects of adding secondary injection ports and changing exit height and secondary injection port...

T. M. Hawkes

1991-01-01

3

Combining Countercurrent Shear Flow Control and Transverse Jets for Fluidic Thrust Vector Control  

Microsoft Academic Search

Countercurrent shear flow control has been established as an effective method for thrust vector control but has been challenged by hardware integration issues. Recent developments in fluidic thrust vector control have focused on nozzle interior methods that skew the throat of the nozzle using multiple transverse jets. The present work is motivated to combine these two flow control approaches to

Ignacio Echavarria Diaz-Guardamino; David Forliti

2007-01-01

4

Effect of Coflow on Counterflow Thrust Vectoring  

Microsoft Academic Search

A unique, fluidic-based thrust vectoring technique known as CounterFlow Thrust Vector Control (CFTVC) has been investigated at the Fluid Mechanics Research Laboratory (FMRL) over the past few years. These studies have demonstrated that CFTVC is a simple, robust and efficient method for thrust vectoring of supersonic jets of various geometries. In an effort to better evaluate the system performance under

F. S. Alvi; A. Krothapalli; P. J. Strykowski

1997-01-01

5

Experimental Study On Counter Flow Thrust Vector Control  

Microsoft Academic Search

Counter Flow Thrust Vectoring (CFTV) is possibly the most promising fluidic thrust vector control method for deflecting the exhaust thrust of a jet engine. CFTV works by generating a countercurrent shear layer in one side of a planar jet and hence by altering the transverse pressure gradient across the jet. Prediction and control of vector angle is the most important

Maria S. Madruga; Debopam Das; Paul J. Strykowski

2000-01-01

6

Fluidic thrust vector control  

Microsoft Academic Search

The design and testing of a fluidic control nozzle for tactical missile thrust vector control (TVC) are discussed. Attention is given to a nozzle with a circular cross section up to the point of flow separation, two control ports that alternately open and close, and a nozzle extension downstream of the control ports being a two-dimensional rectangular slot. Design of

V. E. Haloulakos

1982-01-01

7

Fluidic thrust vector control  

NASA Astrophysics Data System (ADS)

The design and testing of a fluidic control nozzle for tactical missile thrust vector control (TVC) are discussed. Attention is given to a nozzle with a circular cross section up to the point of flow separation, two control ports that alternately open and close, and a nozzle extension downstream of the control ports being a two-dimensional rectangular slot. Design of the TVC system involved characterizing the flow and the sensitivity parameters, the dynamic response, and the performance of hot-gas firings. The test firings verified the feasibility of a nozzle that could withstand 5000 F, the use of thrust vector angles of over 20 deg. A dynamic model test demonstrated a repeatable performance with pressures up to 2000 psia, driving frequencies up to 50 Hz, and a response of 10-15 msec. Adjustment of the chamber pressures permitted equivalent performance using with different heat ratios during cold dynamic tests with CH4.

Haloulakos, V. E.

8

STOL Tactical Aircraft Investigation. Volume IV. Analysis of Wind Tunnel Data: Vectored Thrust/Mechanical Flaps and Internally Blown Jet Flaps.  

National Technical Information Service (NTIS)

The report presents the analysis of 728 hours of testing, conducted in the Boeing V/STOL 20 x 20 ft. Wind Tunnel, on a model of a medium STOL transport with vectored thrust and jet flap powered-lift systems. The interactions between the two powered lift s...

J. L. Lee J. P. Palmer J. R. Monk

1973-01-01

9

Experimental Study On Counter Flow Thrust Vector Control  

NASA Astrophysics Data System (ADS)

Counter Flow Thrust Vectoring (CFTV) is possibly the most promising fluidic thrust vector control method for deflecting the exhaust thrust of a jet engine. CFTV works by generating a countercurrent shear layer in one side of a planar jet and hence by altering the transverse pressure gradient across the jet. Prediction and control of vector angle is the most important aspect in any thrust vectoring system. Experiments are conducted to obtain pressure distribution on the collar surface, which is used with a vacuum system to generate counter flow on one side of a rectangular (aspect ratio 4:1) jet. The exit Mach number of the ideally expanded jet considered here is 1.44. Gap height between the nozzle and collar surface is varied and vector angle for different mass flow rate has been obtained. The condition at which the jet attaches with the collar surface is found and compared with the predicted theoretical results.

Madruga, Maria S.; Das, Debopam; Strykowski, Paul J.

2000-11-01

10

Effect of Coflow on Counterflow Thrust Vectoring  

NASA Astrophysics Data System (ADS)

A unique, fluidic-based thrust vectoring technique known as CounterFlow Thrust Vector Control (CFTVC) has been investigated at the Fluid Mechanics Research Laboratory (FMRL) over the past few years. These studies have demonstrated that CFTVC is a simple, robust and efficient method for thrust vectoring of supersonic jets of various geometries. In an effort to better evaluate the system performance under real flight conditions, a study of the CFTVC system under "wind-on" conditions, using a rectangular Mach 1.4 jet, is currently in progress. The wind-on condition is simulated by providing a coflowing stream (i.e. flowing in the same direction as the primary jet) at the periphery of the countercurrent stream which surrounds the primary jet. Coflowing streams over a range of Mach numbers, from 0.3 to 0.7, will be tested. Preliminary results show that the coflowing stream has a relatively minor influence on CFTVC and that the jet can be easily vectored to large angles in the presence of coflow. These encouraging reuslts further demonstrate the potential of this system for future propulsion applications.

Alvi, F. S.; Krothapalli, A.; Strykowski, P. J.

1997-11-01

11

Feedback control for counterflow thrust vectoring  

Microsoft Academic Search

Thrust vector control is used to increase the maneuverability of aircraft. In current aircraft it is implemented using movable control surfaces such as vanes and flaps. Counterflow thrust vectoring (CFTV) is a fluidic approach to thrust vectoring that has the potential to improve on the conventional approaches by reducing weight and increasing the reaction speed. Open loop implementation of CFTV

Emmanuel G. Collins; Yanan Zhao; F. Alvi; M. I. Alidu; P. J. Strykowski

2004-01-01

12

An experimental investigation of active control of thrust vectoring nozzle flow fields  

Microsoft Academic Search

Fluidic thrust vector control is examined in a supersonic rectangular jet having a 4:1 aspect ratio. Experiments conducted at a Mach number of 2 reveal that the thrust vector angle of the jet can be continuously varied by up to at least 16 deg by applying a counterflowing stream to one of the primary jet shear layers. A technique using

P. J. Strykowski; A. Krothapalli

1994-01-01

13

Rotary-Jet Thrust Augmentor with Jet-Flapped Blades  

Microsoft Academic Search

The concepts and the mechanisms of thrust augmentation are analyzed. The theoretical performance of different types of thrust augmentors is discussed with an emphasis on the Rotary-Jet ejector. The application of thrust augmentors to STOVL aircrafts and the merits of the ejector in this application are discussed where the theoretical performance of the Rotary-Jet is shown to be particularly attractive.

Stephane Jean Cordier

1989-01-01

14

Theory of an Ideal Jet Thrust Augmentor  

Microsoft Academic Search

A theory of the ideal jet thrust augmentor is presented. The conditions of optimal outflow of the active (primary) and passive (secondary) jets from the device under consideration are obtained by solving the variational problem of maximum average thrust realization. The inlet values of the mass and total enthalpy fluxes for both flows, their entropies, and the inlet value of

N. L. Efremov; A. N. Kraiko

2004-01-01

15

Nonlinear dynamics of a vectored thrust aircraft  

Microsoft Academic Search

With realistic relations for the aerodynamic coefficients, numerical simulation is applied to study the longitudinal dynamics of a vectored thrust aircraft in the post-stall regime. As function of the thrust magnitude and the thrust vectoring angle the equilibrium state exhibits three Hopf bifurcations and two saddle-node bifurcations. Even when the equilibrium is stable, weakly damped oscillations occur with a period

Claus B. Sørensen; Erik Mosekilde; Péter Gránásy

1996-01-01

16

COMPUTATIONAL STUDY OF FLUIDIC THRUST VECTORING USING SEPARATION CONTROL IN A NOZZLE  

Microsoft Academic Search

A computational investigation of a two- dimensional nozzle was completed to assess the use of fluidic injection to manipulate flow separation and cause thrust vectoring of the primary jet thrust. The nozzle was designed with a recessed cavity to enhance the throat shifting method of fluidic thrust vectoring. The structured-grid, computational fluid dynamics code PAB3D was used to guide the

Karen A. Deere; Bobby L. Berrier; Jeffrey D. Flamm

2003-01-01

17

Computational Investigation of Fluidic Counterflow Thrust Vectoring.  

National Technical Information Service (NTIS)

A computational study of fluidic counterflow thrust vectoring has been conducted. Two-dimensional numerical simulations were run using the computational fluid dynamics code PAB3D with two-equation turbulence closure and linear Reynolds stress modeling. Fo...

C. A. Hunter K. A. Deere

1999-01-01

18

Fluidic Thrust Vectoring of an Axisymmetric Exhaust Nozzle at Static Conditions.  

National Technical Information Service (NTIS)

A sub-scale experimental static investigation of an axisymmetric nozzle with fluidic injection for thrust vectoring was conducted at the NASA Langley Jet Exit Test Facility. Fluidic injection was introduced through flush-mounted injection ports in the div...

D. J. Wing V. J. Giuliano

1987-01-01

19

Rotary-Jet Thrust Augmentor with Jet-Flapped Blades.  

NASA Astrophysics Data System (ADS)

The concepts and the mechanisms of thrust augmentation are analyzed. The theoretical performance of different types of thrust augmentors is discussed with an emphasis on the Rotary-Jet ejector. The application of thrust augmentors to STOVL aircrafts and the merits of the ejector in this application are discussed where the theoretical performance of the Rotary-Jet is shown to be particularly attractive. A review of previous steady-flow and Rotary-Jet ejector experimental data shows equivalent performance levels. Recent experimental work on the Rotary-Jet is analyzed and several factors adversely affecting performance are identified and discussed. To address these problems a new configuration is proposed where the rotor is fitted with blades, allowing better control of the primary/secondary interaction. The jet sheet exiting at the trailing edge of the foil forms a jet flap. A two-dimensional analysis of the aerodynamics around a jet-flapped airfoil is performed for the first time using a fluid finite element code. Whereas in previous models the presence of the pressure gradient across the jet sheet is an assumption, its presence is predicted by the present method. Results of a test run show good agreement with experimental results by others. This method is applied to the geometry of blade model #10. An original three-dimensional model of the self -driven, jet-flapped bladed rotor is presented which, given set geometrical parameters and operating conditions, solves at each section for the jet and blade angle and calculates the rotor thrust augmentation. The results of parametric runs identify favorable design trends which are applied to the design of prototype test models. An experimental test program has been performed. Flow visualization and local flow velocity and pressure measurements were used to identify favorable jet sheet characteristics. The presence of losses in the spinning rotor are evidenced. Seven blade models were tested in a parametric study. Rotor thrust augmentation without shroud is on the order of 1.0 with a maximum of 1.14. Within the range of parameters tested, optimum spin and flap angles were identified and a maximum thrust augmentation of 2.18 was reached. Tests with increasing exit to primary area ratio shows a monotonic increase in performance as opposed to the non-bladed rotary -jet, which reached a peak performance at a certain area ratio.

Cordier, Stephane Jean

20

Tertiary Flow Injection Thrust Vectoring System.  

National Technical Information Service (NTIS)

The tertiary flow injection thrust vectoring system adds to the secondary injection system disclosed in patent No. 3,144,752. The system involves the feature of a small amount of mass injection upstream of the secondary injection port to distort the prima...

C. E. Kepler

1965-01-01

21

Thrust vector control using electric actuation  

Microsoft Academic Search

Presently, gimbaling of launch vehicle engines for thrust vector control is generally accomplished using a hydraulic system. In the case of the space shuttle solid rocket boosters and main engines, these systems are powered by hydrazine auxiliary power units. Use of electromechanical actuators would provide significant advantages in cost and maintenance. However, present energy source technologies such as batteries are

Robert T. Bechtel; David K. Hall

1995-01-01

22

Computational Study of a New Dual Throat Fluidic Thrust Vectoring Nozzle Concept.  

National Technical Information Service (NTIS)

A computational investigation of a two-dimensional nozzle was completed to assess the use of fluidic injection to manipulate flow separation and cause thrust vectoring of the primary jet thrust. The nozzle was designed with a recessed cavity to enhance th...

K. A. Deere B. L. Berrier J. D. Flamm S. K. Johnson

2005-01-01

23

Test apparatus for measuring jet engine thrust  

SciTech Connect

This patent describes an apparatus for simultaneously measuring variables to calculate total thrust generated from a turbofan jet engine having a lengthwise axis and which is characterized by (1) a section for generating drive gases, (2) a fan section which rotates about the lengthwise axis in response to the drive gases and which includes (i) exterior blades which rotate with the fan section for generating a propelling force, and (ii) an outer cowling, and (3) an outlet section for exhausting the drive gases to the atmosphere to provide a further propelling force, the apparatus comprising: a. a cradle for supporting the engine; b. means for suspending the cradle from a support structure so as to permit movement of the cradle in the lengthwise direction; c. means for measuring a forward force generated by the drive gases which are exhausted to the atmosphere for calculating the nozzle gas thrust, the measuring means including load cell means which are connected between the support structure and the cradle; d. dynamometer means including a rotatable portion, for measuring a torque generated by the engine fan section for calculating the thrust output of the fan section; and e. drive gear means for connecting the dynamometer means to the engine fan section, the drive gear means including belt means which are removably connected to the fan section and to the rotatable portion of the dynamometer means so as to transmit a rotational force between the fan section and the dynamometer means.

Laskody, J.R.

1988-12-06

24

An experimental investigation of active control of thrust vectoring nozzle flow fields  

NASA Astrophysics Data System (ADS)

Fluidic thrust vector control is examined in a supersonic rectangular jet having a 4:1 aspect ratio. Experiments conducted at a Mach number of 2 reveal that the thrust vector angle of the jet can be continuously varied by up to at least 16 deg by applying a counterflowing stream to one of the primary jet shear layers. A technique using counterflow eliminates the bistable response known to plague fluidic elements and is shown to be effective in both hot and cold supersonic jets. Results are presented for jet stagnation temperatures between 300 K and 670 K. Measurements indicate that the thrust vector control is both efficient as well as a linear function of the static pressure developed in the counterflowing stream. The typical power required to vector the jet at 16 degrees was estimated to be less than 1 percent of the power developed in the primary jet. Thrust vector control employing counterflow has several advantages over current technologies, the most important of which is the elimination of movable control surfaces which add considerable weight to the aircraft.

Strykowski, P. J.; Krothapalli, A.

1994-01-01

25

EXPERIMENTAL STUDY OF A NOZZLE USING FLUIDIC COUNTERFLOW FOR THRUST VECTORING  

Microsoft Academic Search

A static experimental investigation of a counterflow thrust vectoring nozzle concept was performed. The study was conducted in the NASA Langley Research Center Jet Exit Test Facility. Internal performance characteristics were defined over a nozzle pressure ratio (jet total to ambient) range of 3.5 to 10.0. The effects of suction collar geometry and suction slot height on nozzle performance were

Jeffrey D. Flamm

1998-01-01

26

Numerical investigation of thrust vectoring by injection of secondary air into nozzle flows  

NASA Astrophysics Data System (ADS)

Injection of secondary air into nozzle flows is an efficient method to control the thrust vector angle of an aircraft. A numerical investigation of thrust vectoring has been carried out for hypersonic aircraft in the transonic flight regime. In this speed range, single duct asymmetrical single expansion ramp nozzles operate far off design due to large nozzle exit areas required for optimal thrust coefficients at hypersonic cruise Mach numbers, thus producing large thrust components in the downward direction. Injecting secondary air into the nozzle flow in the critical transonic flight Mach number regime can lead to favorable gross thrust vector angles and thus improved thrust efficiency in flight direction. For a hypersonic aircraft's rectangular convergent-divergent nozzle configuration with a single expansion ramp, two dimensional Euler calculations of the complete afterbody flow field were carried out in the transonic flight regime, investigating subsonic as well as supersonic injection of the aircraft's forebody boundary layer air into the nozzle flow. Subsonic flow of the injected air along the expansion ramp produces a favorable pressure distribution on the ramp and results in advantageous thrust vectors with small force components normal to the flight direction and in best thrust efficiency. The interaction between the external flow, the jet plume flow, and the secondary air flow, as well as the behavior of the thrust vector, due to pressure and temperature variations of the injected forebody boundary layer air, are discussed. Also investigated was the impact of the aircraft's angle of attack on the complete nozzle flow field.

Berens, T.

1993-11-01

27

Computational Investigation of the Aerodynamic Effects on Fluidic Thrust Vectoring.  

National Technical Information Service (NTIS)

A computational investigation of the aerodynamic effects on fluidic thrust vectoring has been conducted. Three-dimensional simulations of a two-dimensional, convergent-divergent (2DCD) nozzle with fluidic injection for pitch vector control were run with t...

K. A. Deere

2000-01-01

28

Reduced-length scarfed-nozzles for thrust vector adjustment  

NASA Astrophysics Data System (ADS)

The results of an investigation into the utilization of scarfed, truncated perfect-nozzles for thrust vector adjustment in tactical strap-on boosters is presented. The use of truncated perfect-nozzle expansion contours was evaluated as a means of achieving significant nozzle length reductions over conical nozzle designs without degrading axial thrust or thrust vector adjustment capability. Previously developed perfect-nozzle and scarfed-nozzle performance analysis computer codes were used to generate an extensive parametric study which characterized the influence of nozzle length and expansion ratio on axial thrust and thrust vector adjustment capability. Comparisons were made against the results obtained for scarfed-nozzles with conical expansion contours. The parametric study was utilized to develop a general scarfed truncated perfect-nozzle design. The axial performance and thrust vector adjustment capability of the nozzle design was experimentally verified through solid rocket motor static firings.

Lilley, Jay S.

1993-04-01

29

Ground Test of the D Shaped Vented Thrust Vectoring Nozzle.  

National Technical Information Service (NTIS)

Static ground tests of a large scale lift/cruise thrust vectoring nozzle were conducted to establish: (1) vectoring performance 'in' and 'out' of ground effect; (2) thrust spoilage capability; (3) compatibility of the nozzle with a turbotip fan; and (4) t...

D. W. Esker

1976-01-01

30

Estimation of thrust and mass flow in a jet engine  

Microsoft Academic Search

This paper addresses the problem of estimating unmeasurable quantities as the thrust and mass flow in a jet engine. An analytical single spool turbo jet engine model is for the sake of simplicity used as an example. A reduced order observer, in combination with a reduced order model, is deduced and compared to a full order Kalman filter using a

Mattias Henriksson; Claes Breitholtz

2004-01-01

31

High Thrust to Weight Bipropellant Reentry Vehicle Thrust Vector Control Thru Micro-Miniaturization.  

National Technical Information Service (NTIS)

With the advent of nanosat and picosat-size satellites, the design of miniature, efficient, high thrust-to-weight (T/W) ratio thrust vector control (TVC) thrusters with liquid bipropellants has been evolving. The extremely high T/W ratios achievable with ...

W. Figueiredo

2003-01-01

32

Solid Rocket Booster Thrust Vector Control Subsystem Description.  

National Technical Information Service (NTIS)

Major Solid Rocket Booster-Thrust Vector Control (SRB-TVC) subsystem components and subcomponents used in the Space Transportation System (STS) are identified. Simplified schematics, detailed schematics, figures, photographs, and data are included to acqu...

J. Redmon

1983-01-01

33

Design Enhancements of the Two-Dimensional, Dual Throat Fluidic Thrust Vectoring Nozzle Concept.  

National Technical Information Service (NTIS)

A Dual Throat Nozzle fluidic thrust vectoring technique that achieves higher thrust-vectoring efficiencies than other fluidic techniques, without sacrificing thrust efficiency has been developed at NASA Langley Research Center. The nozzle concept was desi...

J. D. Flamm K. A. Deere M. L. Mason B. L. Berrier S. K. Johnson

2006-01-01

34

Thrust vector control control using internal airfoils  

SciTech Connect

This patent describes an exhaust nozzle for an engine which generates thrust expulsion of gaseous products of fuel combustion. It comprises: a generally axisymmetric housing defined along a central thrust axis including a wall structure defining an exhaust duct, and axially adjacent radially inwardly converging portion, throat portion and radially outwardly diverging portion; and at least one airfoil sized to protrude into the exhaust a distance corresponding to about 15 to 35 percent of diameter of the throat portion disposed within the divergent portion at a location axially spaced from the axis portion a distance corresponding to from 20 per cent to 25 per cent of the axial extent of the divergent portion, the airfoil mounted on the wall structure for rotation about an axis substantially perpendicular to the thrust axis.

Herup, E.J.; Franke, M.E.; Friddell, J.H.

1992-10-13

35

FLUIDIC THRUST VECTORING OF AN AXISYMMETRIC EXHAUST NOZZLE AT STATIC CONDITIONS  

Microsoft Academic Search

A sub-scale experimental static investigation of an axisymmetric nozzle with fluidic injection for thrust vectoring was conducted at the NASA Langley Jet Exit Test Facility. Fluidic injection was introduced through flush-mounted injection ports in the divergent section. Geometric variables included injection-port geometry and location. Test conditions included a range of nozzle pressure ratios from 2 to 10 and a range

David J. Wing; Victor J. Giuliano

36

Feedback control for counterflow thrust vectoring with a turbine engine: Experiment design and robust control design and implementation  

Microsoft Academic Search

Engineering research over the last few years has successfully demonstrated the potential of thrust vector control using counterflow at conditions up to Mach 2. Flow configurations that include the pitch vectoring of rectangular jets and multi-axis vector control in diamond and axisymmetric nozzle geometries have been studied. Although bistable (on-off) fluid-based control has been around for some time, the present

Delfim Zambujo Das Dores

2005-01-01

37

Computational Investigation of Fluidic Counterflow Thrust Vectoring  

Microsoft Academic Search

A computational study of fluidic counterflow thrustvectoring has been conducted. Two-dimensionalnumerical simulations were run using the computationalfluid dynamics code PAB3D with two-equationturbulence closure and linear Reynolds stress modeling.For validation, computational results were compared toexperimental data obtained at the NASA Langley JetExit Test Facility. In general, computational resultswere in good agreement with experimental performancedata, indicating that efficient...

C. A. Hunter; K. A. Deere

1999-01-01

38

Design and test of electromechanical actuators for thrust vector control  

Microsoft Academic Search

New control mechanisms technologies are currently being explored to provide alternatives to hydraulic thrust vector control (TVC) actuation systems. For many years engineers have been encouraging the investigation of electromechanical actuators (EMA) to take the place of hydraulics for spacecraft control\\/gimballing systems. The rationale is to deliver a lighter, cleaner, safer, more easily maintained, as well as energy efficient space

J. R. Cowan; Rae Ann Weir

1993-01-01

39

Aircraft Ground Test and Subscale Model Results of Axial Thrust Loss Caused by Thrust Vectoring Using Turning Vanes.  

National Technical Information Service (NTIS)

The NASA-Dryden F/A-18 high alpha research vehicle was modified to incorporate three independently controlled turning vanes located aft of the primary nozzle of each engine to vector thrust for pitch and yaw control. Ground measured axial thrust losses we...

S. A. Johnson

1992-01-01

40

An Investigation of Corner Separation within a Thrust Augmenter Having Coanda Jets.  

National Technical Information Service (NTIS)

An investigation was conducted to determine the way separation develops in the corners of thrust augmenter wings, having Coanda jets. Hot film surface sensors and pressure transducers were used, and the results indicated that separation on the test augmen...

M. R. Seiler

1977-01-01

41

SUMMARY OF FLUIDIC THRUST VECTORING RESEARCH CONDUCTED AT NASA LANGLEY RESEARCH CENTER  

Microsoft Academic Search

Interest in low-observable aircraft and in lowering an aircraft's exhaust system weight sparked decades of research for fixed geometry exhaust nozzles. The desire for such integrated exhaust nozzles was the catalyst for new fluidic control techniques; including throat area control, expansion control, and thrust-vector angle control. This paper summarizes a variety of fluidic thrust vectoring concepts that have been tested

Karen A. Deere

2003-01-01

42

Implicit time-marching solution of the Navier-Stokes equations for thrust reversing and thrust vectoring nozzle flows  

NASA Astrophysics Data System (ADS)

An implicit finite volume method is investigated for the solution of the compressible Navier-Stokes equations for flows within thrust reversing and thrust vectoring nozzles. Thrust reversing nozzles typically have sharp corners, and the rapid expansion and large turning angles near these corners are shown to cause unacceptable time step restrictions when conventional approximate factorization methods are used. In this investigation these limitations are overcome by using second-order upwind differencing and line Gauss-Siedel relaxation. This method is implemented with a zonal mesh so that flows through complex nozzle geometries may be efficiently calculated. Results are presented for five nozzle configurations including two with time varying geometries. Three cases are compared with available experimental data and the results are generally acceptable.

Imlay, S. T.

1986-11-01

43

Experimental Study of an Axisymmetric Dual Throat Fluidic Thrust Vectoring Nozzle for Supersonic Aircraft Application.  

National Technical Information Service (NTIS)

An axisymmetric version of the Dual Throat Nozzle concept with a variable expansion ratio has been studied to determine the impacts on thrust vectoring and nozzle performance. The nozzle design, applicable to a supersonic aircraft, was guided using the un...

B. L. Berrier J. D. Flamm K. A. Deere M. L. Mason S. K. Johnson

2007-01-01

44

High Thrust to Weight Bipropellant Reentry Vehicle Thrust Vector Control Thru Micro-Miniaturization.  

National Technical Information Service (NTIS)

These briefing charts represent a speech given by the author at the AIAA Joint Propulsion Conference held in Huntsville, Alabama, on 20-23 2003. The speech covered the following topics: the high thrust-to-weight ratios achievable through micro-miniaturiza...

B. Figueiredo

2003-01-01

45

Steady-State Thrust Augmentors and Jet Pumps.  

National Technical Information Service (NTIS)

The state of the art in steady-state augmentors and jet pumps is briefly reviewed and a general performance theory developed. Generalized charts are presented giving the augmentation ratio obtainable from an optimized eductor, together with the associated...

P. R. Payne

1966-01-01

46

Hands-On Laboratory Experience via Remote Control: Jet Thrust Laboratory  

Microsoft Academic Search

This paper describes the development of a remote-controlled jet thrust laboratory for illustrating the fundamentals of compressible fluid mechanics as part of an undergraduate mechanical engineering curriculum. The laboratory is the first in a series to be developed jointly by faculty at Rutgers University and the University of Illinois at Urbana-Champagne. The sharing of resources significantly reduces the per institution

Madara Ogot; Gregory Elliott; Nick Glumac

2002-01-01

47

Variation of Pitching Moment with Engine Thrust for a Twin-Engine Commercial Jet Aircraft.  

National Technical Information Service (NTIS)

Flight tests were made to determine the effect of engine net thrust on airplane pitching moment for a twin-engine commercial jet transport in the approach, climbout and descent, and cruise configurations. The results indicate that for all the conditions a...

R. E. Shanks

1977-01-01

48

NLO Vector Boson Production With Light Jets  

SciTech Connect

In this contribution we present recent progress in the computation of next-to-leading order (NLO) QCD corrections for the production of an electroweak vector boson in association with jets at hadron colliders. We focus on results obtained using the virtual matrix element library BlackHat in conjunction with SHERPA, focusing on results relevant to understanding the background to top production. The production of a vector boson in association with several jets at the Large Hadron Collider (LHC) is an important background for other Standard Model processes as well as new physics signals. In particular, the production of a W boson in association with many jets is an important background for processes involving one or more top quarks. Precise predictions for the backgrounds are crucial to measurement of top-quark processes. Vector boson production in association with multiple jets is also a very important background for many SUSY searches, as it mimics the signatures of many typical decay chains. Here we will discuss how polarization information can be used as an additional handle to differentiate top pair production from 'prompt' W-boson production. More generally, ratios of observables, for example for events containing a W boson versus those containing a Z boson, are expected to be better-behaved as many uncertainties cancel in such ratios. Precise calculation of ratios, along with measurement of one of the two processes in the ratio, can be used in data-driven techniques for estimating backgrounds.

Bern, Z.; Diana, G.; Dixon, L.J.; Febres Cordero, F.; Forde, D.; Gleisberg, T.; Hoeche, S.; Ita, H.; Kosower, D.A.; Maitre, D.; Ozeren, K.

2012-02-15

49

Development and qualification of a STAR 48 rocket motor with thrust vector control  

NASA Astrophysics Data System (ADS)

A thrust vector control (TVC) nozzle for use on the STAR 48 rocket motor (STAR 48V) has been developed for use on the COMET program aboard the Conestoga launch vehicle. The first stages of qualification testing have been completed. The first STAR 48V has been successfully static-tested. The flexseal TVC nozzle design is based upon the qualified and flight-proven fixed nozzle design used on spin-stabilized spacecraft. The flexseal design and fabrication approach benefit from flight-proven and man-rated Thiokol Corporation flexseal designs. The thrust vector control system provides vectoring capability to 4 deg for use on nonspinning spacecraft. Electromechanical actuators coupled with a closed-loop controller provide thrust vector positioning and spacecraft attitude control.

Hamke, R.; Rade, J.; Weldin, R.

1992-07-01

50

Investigation of acoustic interactions in jet thrust augmenting ejectors  

Microsoft Academic Search

The performance of a constant area rectangular ejector with varying mixing length was investigated to determine the aeroacoustic interaction effects. The rectangular ejector investigation was conducted in two phases. The phase one investigation involved the testing of three different aspect ratio rectangular convergent nozzles at pressures between 15-45 psig to determine the acoustic and jet spreading characteristics. From these data

J. R. Campbell; K. D. Korkan; H. Viets

1981-01-01

51

Modeling and Thrust Optimization of a Bio-Inspired Pulsatile Jet Thruster  

NASA Astrophysics Data System (ADS)

A new type of thruster technology offers promising low speed maneuvering capabilities for underwater vehicles. Similar to the natural locomotion of squid and jellyfish the thruster successively forces fluid jets in and out of a small internal cavity. We investigate several properties of squid and jellyfish locomotion to drive the thruster design including actuation of nozzle geometry and vortex ring thrust augmentation. The thrusters are compact with no extruding components to negatively impact the vehicle's drag. These devices have thrust rise-times orders of magnitude faster than those reported for typical propeller thrusters, making them an attractive option for high accuracy underwater vehicle maneuvering. The dynamics of starting jet circulation, impulse, and kinetic energy are derived in terms of kinematics at the entrance boundary of a semi-infinite domain, specifically identifying the effect of a non-parallel incoming flow. A model for pressure at the nozzle is derived without the typical reliance on a predetermined potential function, making it a powerful tool for modeling any jet flow. Jets are created from multiple nozzle configurations to validate these models, and velocity and vorticity fields are determined using DPIV techniques. A converging starting jet resulted in circulation 90--100%, impulse 70--75%, and energy 105--135% larger than a parallel starting jet with identical volume flux and piston velocity, depending on the stroke ratio. The new model is a much better predictor of the jet properties than the standard 1D slug model. A simplified thrust model, was derived to describe the high frequency thruster characteristics. This model accurately predicts the average thrust, measured directly, for stroke ratios up to a critical value where the leading vortex ring separates from the remainder of the shear flow. A new model predicting the vortex ring pinch-off process is developed based on characteristic centerline velocities. The vortex ring pinch-off is coincides with this velocity criterion, for all cases tested. Piston velocity program and nozzle radius are optimized with respect to average thrust, and a quantity similar to propulsive efficiency. The average thrust is maximized by a critical nozzle radius. An approximate linear time-invariant (LTI) model of the thruster vehicle system was derived which categorizes maneuvers into different characteristic regimes. Initial thruster testing showed that open and closed loop frequency response were sufficiently approximated by the LTI model, and that the thruster is ideally suited for small scale high accuracy maneuvers.

Krieg, Michael W.

52

Control of Ducted Fan Flying Object Using Thrust Vectoring  

NASA Astrophysics Data System (ADS)

Recently, R/C helicopter is used in fields of aerial photography and aerial investigation. But helicopter rotor blades are not covered, and the thrust is generated by high rotational speed. Thus R/C helicopter has a high risk of damage. In this study, we developed a new flying object using ducted fans instead of rotor blades. At first, PD control was employed for pitch and roll attitude control, but it caused steady state error. Moreover, PI-D control was used instead of PD control, and it reduced the steady state error. We succeeded to achieve stable hovering by 3-axes (roll, pitch and yaw axis) attitude control.

Miwa, Masafumi; Shigematsu, Yuki; Yamashita, Takashi

53

Performance Characteristics of Two Multiaxis Thrust-Vectoring Nozzles at Mach Numbers Up to 1.28.  

National Technical Information Service (NTIS)

The thrust-vectoring axisymmetric (VA) nozzle and a spherical convergent flap (SCF) thrust-vectoring nozzle were tested along with a baseline nonvectoring axisymmetric (NVA) nozzle in the Langley 16-Foot Transonic Tunnel at Mach numbers from 0 to 1.28 and...

D. J. Wing F. J. Capone

1993-01-01

54

Trajectory tracking control for the planar dynamics of a thrust vectored airship  

Microsoft Academic Search

This paper addresses and solves the trajectory tracking problem for the planar dynamics of a thrust vectored airship. The proposed controller is based on a combination of two nonlinear control design techniques, backstepping and exact tracking error dynamics passive output feedback (ETDPOF). Numerical simulations show the performance of the proposed controller and some concluding remarks complete the paper.

G. Murguia-Rendon; H. Rodriguez-Cortes; M. Velasco-Villa

2009-01-01

55

Robust synthesized control of electromechanical actuator for thrust vector system in spacecraft  

Microsoft Academic Search

A kind of robust control of electromechanical actuator (EMA) system for thrust vector control in a spacecraft was investigated. In the flight of a spacecraft, the EMA system must overcome the influence of load disturbance and working point alteration to improve the robust control performances. Addressing this problem and considering the large inertia and low stiffness load of the EMA

Hao Lu; Yunhua Li; Chenglin Zhu

56

Posture Control of Electromechanical-Actuator-Based Thrust Vector System for Aircraft Engine  

Microsoft Academic Search

This paper deals with the dynamical modeling and posture control of the electromechanical actuator (EMA)-based thrust vector control (TVC) system for aircraft engines. Addressing the issues of the large inertia and low stiffness existing in the TVC system driven by EMA, this paper established a 2-DOF mathematical model to describe the EMA dynamic characteristics. In order to overcome the influence

Yunhua Li; Hao Lu; Shengli Tian; Zongxia Jiao; Jian-Tao Chen

2012-01-01

57

Simultaneous thrust vector control and vibration isolation of satellites using steerable smart platforms  

Microsoft Academic Search

This paper presents an innovative concept, control strategies and experimental verification of simultaneous thrust vector control and vibration isolation of satellites. First, the innovative concept is introduced by employing a smart platform as an active structural interface between the main thruster of a satellite and the satellite structure. Second, the inverse kinematics and singularity analysis of the smart platform are

Mehrdad N. Ghasemi-Nejhad; Kougen Ma

2010-01-01

58

Investigation of acoustic interactions in jet thrust augmenting ejectors  

NASA Astrophysics Data System (ADS)

The performance of a constant area rectangular ejector with varying mixing length was investigated to determine the aeroacoustic interaction effects. The rectangular ejector investigation was conducted in two phases. The phase one investigation involved the testing of three different aspect ratio rectangular convergent nozzles at pressures between 15-45 psig to determine the acoustic and jet spreading characteristics. From these data a rectangular ejector incorporating endwall and ejector flap blowing was fabricated and investigated at pressure ratios between 2.0 and 5.0. These investigations were conducted at ejector flap length (L) to ejector throat widths (W), L/W of 11.0, 9.5, 8.0, 6.5, 5.0, 3.5, 2.0, and 0.9 to determine the ejector performance. The data for the rectangular ejector configuration investigated showed an aeroacoustic interaction in the present ratio range of 3.3 - 3.8. However, the resulting performance was not improved to the degree experienced with axisymmetric ejectors.

Campbell, J. R.; Korkan, K. D.; Viets, H.

1981-03-01

59

Measurements of vector boson plus jets at the Tevatron  

SciTech Connect

We present preliminary measurements of Z/{gamma}* + jets, W + c and Z + b + X at the Tevatron, and review recent measurements of vector boson plus inclusive and heavy-flavor jets production. All measurements are in agreement with next-to-leading-order QCD calculations within the experimental and theoretical uncertainties. We also point to comparisons of the production rate and kinematics of the data with several Monte Carlo simulation programs of vector boson + jets processes.

Cerrito, Lucio; /Queen Mary, U. of London

2010-08-01

60

Development and qualification of a STAR 48 rocket motor with thrust vector control  

Microsoft Academic Search

A thrust vector control (TVC) nozzle for use on the STAR 48 rocket motor (STAR 48V) has been developed for use on the COMET program aboard the Conestoga launch vehicle. The first stages of qualification testing have been completed. The first STAR 48V has been successfully static-tested. The flexseal TVC nozzle design is based upon the qualified and flight-proven fixed

R. Hamke; J. Rade; R. Weldin

1992-01-01

61

Experimental and Computational Investigation of Multiple Injection Ports in a Convergent-Divergent Nozzle for Fluidic Thrust Vectoring.  

National Technical Information Service (NTIS)

A computational and experimental study was conducted to investigate the effects of multiple injection ports in a two-dimensional, convergent-divergent nozzle, for fluidic thrust vectoring. The concept of multiple injection ports was conceived to enhance t...

K. A. Waithe K. A. Deere

2003-01-01

62

Design and evaluation of single and dual flow thrust vector nozzles with post exit vanes  

NASA Astrophysics Data System (ADS)

This Thrust Vectored Research project required that a 1/24 scale model of the F/A-18 High Alpha Research Vehicle, (HARV), propulsion system be constructed on the university campus. This propulsion system was designed for cold flow testing on a multicomponent test rig. Forces and moments were measured to study nozzle performance parameters. The flow visualization technique of color Schlieren photography was performed to investigate the flow phenomena at the nozzle exit. The flow interactions that were identified consisted of vane nozzleing between the outer and lower vanes and vane tip interference. The thrust vectoring system consisted of three asymmetrically spaced vanes installed circumferentially on a maximum afterburner nozzle. The performance of the nozzle was investigated with the outer and lower vanes equally deflected, (-10 deg is less than delta(sub v) is less than 25 deg), and with the upper vane fully retracted, (delta(sub v) equals -10 deg). The nozzle pressure ratio ranged from 4 to 6. The results indicated that a vane nozzleing effect developed at nozzle pressure ratios of 4 and 6 when the outer and lower vanes were deflected far enough into the flow field such that the increase in vane area accelerated the flow past the vanes causing distorted shock waves. This accelerated flow was a result of a pressure differential existing between the inside surface of the vane and the ambient pressure. The stagnation pressure that developed along the inside surface of the vane accelerated the flow past the vanes causing it to equalize with ambient pressure, thus providing distorted shock waves. A tip interference was present at the trailing edge of the upper vane as a result of low nozzle pressure, NPR 4, with high vane deflection, delta(sub v) equals 25 degrees, and also with a high nozzle pressure, NPR 6, and low vane deflections, delta(sub v) equals 15 degrees.

Carpenter, Thomas W.; Vaccarezza, Stephen E.; Dobbins, Sean

1992-12-01

63

Refractory Air Vane and Refractory Material Research and Development. Task II - Refractory Materials for a Thrust Vector Control Valve.  

National Technical Information Service (NTIS)

This document reports the results of a 12-month contract to evaluate candidate refractory and insulator materials for use as the inlet duct liner, rotor, and nozzle exit, of a hot gas thrust vector control system. The purpose of this investigation was to ...

S. B. Moorhead

1974-01-01

64

Simulation of Thrust-Vectored Aircraft Maneuvers on a Human Centrifuge: Model Validation and Design for the Dynamic Environment Simulator.  

National Technical Information Service (NTIS)

This SBIR 2 final report covers three areas: (1) current state of the art of the human factors effects of flying thrust vectored, or supermaneuverable, aircraft, (2) the development and validation of a model of the 3 axis Dynamic Environment Simulator (DE...

J. A. VAN Poppel B. J. Barton D. J. Pancratz M. H. Rangel R. D. Banks

1998-01-01

65

Estimated optimum control of a spacecraft by the rocket engine thrust vector at the extraatmospheric section of the reentry of an artificial earth satellite  

Microsoft Academic Search

The paper investigates optimal, minimum-fuel control of a spacecraft by the rocket engine thrust vector on the extraatmospheric section of the reentry of a satellite. The control design, which provides for firing of the engine twice, is shown to be highly efficient. A high-speed algorithm is developed for calculating the estimated optimum reentry trajectories to the prescribed area of the

N. L. Sokolov; A. P. Sokolov; T. Iu. Smirnova

1992-01-01

66

Advanced solid rocket motor nozzle thrust vector control flexseal development status  

NASA Astrophysics Data System (ADS)

The advanced solid rocket motor (ASRM) flexseal development status is reviewed focusing on design goals and requirements, design configuration, analysis activities, and verification tests. It is concluded that the ASRM flexseal incorporates flight-proven materials in an innovative design configuration. Variable thickness shims and efficient packaging of the flexseal make it possible to achieve a significant weight reduction. A flexseal insulator design derived from strategic solid rocket motor experience will provide the necessary bearing thermal protection while minimizing vectoring torque variability.

Prins, William S.; Meyer, Scott A.; Cox, Paul D.

1992-07-01

67

Design of Supersonic Coanda Jet Nozzles.  

National Technical Information Service (NTIS)

The thrust vectoring of supersonic Coanda jets was improved by designing a nozzle to skew the initial jet velocity profile. A new nozzle design procedure, based on the method of characteristics, was developed to design a nozzle which produces a specified ...

P. M. Bevilaqua J. D. Lee

1987-01-01

68

Vector Boson Jets with BlackHat and Sherpa  

SciTech Connect

We review recent NLO QCD results for W, Z + 3-jet production at hadron colliders, computing using BlackHat and SHERPA, and including also some new results for Z + 3-jet production for the LHC at 7 TeV. We report new progress towards the NLO cross section for W + 4-jet production. In particular, we show that the virtual matrix elements produced by BlackHat are numerically stable. We also show that with an improved integrator and tree-level matrix elements from BlackHat, SHERPA produces well-behaved real-emission contributions. As an illustration, we present the real-emission contributions - including dipole-subtraction terms - to the p{sub T} distribution of the fourth jet, for a single subprocess with the maximum number of gluons.

Berger, C.F.; /MIT, LNS; Bern, Z.; /UCLA; Dixon, Lance J.; /SLAC; Cordero, F.Febres; /Simon Bolivar U.; Forde, D.; /CERN /NIKHEF, Amsterdam; Gleisberg, T.; /SLAC; Ita, H.; /UCLA; Kosower, D.A.; /Saclay, SPhT; Maitre, D.; /Durham U.

2010-08-25

69

The Effect Of Counterflow On The Acoustic Characteristics Of A Mach 1.44 Rectangular Jet  

Microsoft Academic Search

The application of counterflow around the periphery of a jet has been used to achieve elevated mixing levels in compressible shear layers and to provide fluidic thrust vector control of supersonic jets. Due to these benefits, an investigation is undertaken to determine the effect of counterflow on the acoustic properties of supersonic jets. Specifically, the aeroacousitc properties of a Mach

C. Shih; F. S. Alvi; A. Krothapalli

1996-01-01

70

Using jet mass to discover vector quarks at the CERN LHC  

NASA Astrophysics Data System (ADS)

We illustrate the utility of jet-mass distributions as probes of new physics at the LHC, focusing on a heavy vector-quark doublet that mixes with the top as a concrete example. For 1 TeV vector-quark masses, we find that signals with greater than 5? significance can be achieved after 100fb-1. More generally, jet-mass distributions have the potential to provide signals for heavy states that produce highly boosted weak gauge bosons and/or top quarks.

Skiba, Witold; Tucker-Smith, David

2007-06-01

71

Optimal thrust characteristics of a synthetic jet actuator for application in low speed maneuvering of underwater vehicles  

Microsoft Academic Search

Compact zero-mass pulsatile jet actuators are proposed for low speed maneuvering and station keeping of small underwater vehicles. The flow field of such jets are initially dominated by vortex ring formation. Prototypes of such actuators are built and tested. The current actuator design has a mechanical plunger system to generate pulsatile jets, whose oscillation frequency is varied between zero and

Michael Krieg; Aravind Pitty; Mostafa Salehi; Kamran Mohseni

2005-01-01

72

Search for vector-like quark production in the lepton+jets and dilepton+jets final states using 5.4 fb-1 of Run II data  

SciTech Connect

The Standard Model of particle physics provides an excellent description of particle interactions at energies up to {approx}1 TeV, but it is expected to fail above that scale. Multiple models developed to describe phenomena above the TeV scale predict the existence of very massive, vector-like quarks. A search for single electroweak production of such particles in p{anti p} collisions at a center-of-mass energy of 1.96 TeV is performed in the W+jets and Z+jets channels. The data were collected by the D0 detector at the Fermilab Tevatron Collider and correspond to an integrated luminosity of 5.4 fb{sup -1}. Events consistent with a heavy object decaying to a vector boson and a jet are selected. We observe no significant excess in comparison to the background prediction and set 95% confidence level upper limits on production cross sections for vector-like quarks decaying to W+jet and Z+jet. Assuming a vector-like quark -- standard model quark coupling parameter {tilde {kappa}}{sub qQ} of unity, we exclude vector-like quarks with mass below 693 GeV for decays to W+jet and mass below 449 GeV for decays to Z+jet. These represent the most sensitive limits to date.

Caughron, Seth; /Columbia U.

2010-10-01

73

Vector boson plus one jet production in POWHEG  

NASA Astrophysics Data System (ADS)

We present an implementation of the next-to-leading order vector boson plus one jet production process in hadronic collision in the framework of POWHEG, which is a method to implement NLO calculations within a Shower Monte Carlo context. All spin correlations in the vector boson decay products have been taken into account. The process has been implemented in the framework of the POWHEG BOX, an automated computer code for building implementations of NLO calculations that can be interfaced to a shower Monte Carlo program. We present phenomenological results for the case of the Z/ ? plus one jet production process, obtained by matching the POWHEG calculation with the shower performed by PYTHIA, for the LHC, and we compare our results with available Tevatron data.

Alioli, Simone; Nason, Paolo; Oleari, Carlo; Re, Emanuele

2011-01-01

74

Charge-charge correlations and the detection of weak vector bosons by hadronic jets inbar pp and pp collisions at collider energies  

NASA Astrophysics Data System (ADS)

We study the charge properties of quark jets within a chain decay model for quark jet fragmentation. Using the charge properties of quark jets, we define charge-charge two-jet cross sections and correlations. Inbar pp collisions these correlations show significant structure due to the weak vector bosons W ± and Z 0.

Ranft, J.; Ritter, S.

1981-09-01

75

Towards pp ? VVjj at NLO QCD: bosonic contributions to triple vector boson production plus jet  

NASA Astrophysics Data System (ADS)

In this work, some of the NLO QCD corrections for pp ? VVjj + X are presented. A program in Mathematica based on the structure of Feyn Calc which automatically simplifies a set of amplitudes up to the hexagon level of rank 5 has been created for this purpose. We focus on two different topologies. The first involves all the virtual contributions needed for quadruple electroweak vector boson production, i.e. pp ? VVVV + X. In the second, the remaining "bosonic" corrections to electroweak triple vector boson production with an additional jet ( pp ? VVVj + X) are computed. We show the factorization formula of the infrared divergences of the bosonic contributions for VVVV and VVVj production with V ? ( W, Z, ?). Stability issues associated with the evaluation of the hexagons up to rank 5 are studied. The CPU time of the FORTRAN subroutines rounds the 2 milliseconds and seems to be competitive with other more sophisticated methods. Additionally, in appendix A the master equations to obtain the tensor coefficients up to the hexagon level in the external momenta convention are presented including the ones needed for small Gram determinants.

Campanario, Francisco

2011-10-01

76

Thrust and Propulsive Efficiency from an Instructive Viewpoint  

ERIC Educational Resources Information Center

|In a typical engineering or physics curriculum, the momentum equation is used for the determination of jet engine thrust. Even a simple thrust analysis requires a heavy emphasis on mathematics that can cause students and engineers to lose a physical perspective on thrust. This article provides for this physical understanding using only static…

Kaufman, Richard D.

2010-01-01

77

THRUST BEARING  

DOEpatents

A thrust bearing suitable for use with a rotor or blower that is to rotate about a vertical axis is descrihed. A centrifagal jack is provided so thnt the device may opernte on one hearing at starting and lower speeds, and transfer the load to another bearing at higher speeds. A low viscosity fluid is used to lubricate the higher speed operation bearing, in connection with broad hearing -surfaces, the ability to withstand great loads, and a relatively high friction loss, as contraated to the lower speed operatio;n bearing which will withstand only light thrust loads but is sufficiently frictionfree to avoid bearing seizure during slow speed or startup operation. An axially aligned shaft pin provides the bearing surface for low rotational speeds, but at higher speed, weights operating against spring tension withdraw nthe shaft pin into the bearing proper and the rotor shaft comes in contact with the large bearing surfaces.

Heller, P.R.

1958-09-16

78

Jets.  

PubMed

This is a discussion of concentrated large-scale flows in planetary atmospheres and oceans, argued from the viewpoint of basic geophysical fluid dynamics. We give several elementary examples in which these flows form jets on rotating spheres. Jet formation occurs under a variety of circumstances: when flows driven by external stress have a rigid boundary which can balance the Coriolis force, and at which further concentration can be caused by the beta effect; when there are singular lines like the line of vanishing windstress or windstress-curl, or the Equator; when compact sources of momentum, heat or mass radiate jet-like beta plumes along latitude circles; when random external stirring of the fluid becomes organized by the beta effect into jets; when internal instability of the mass field generates zonal flow which then is concentrated into jets; when bottom topographic obstacles radiate jets, and when frontogenesis leads to shallow jet formation. Essential to the process of jet formation in stratified fluids is the baroclinic life cycle described in geostrophic turbulence studies; there, conversion from potential to kinetic energy generates eddy motions, and these convert to quasibarotropic motions which then radiate and induce jet-like large-scale circulation. Ideas of potential vorticity stirring by eddies generalize the notion of Rossby-wave radiation, showing how jets embedded in an ambient potential vorticity gradient (typically due to the spherical geometry of the rotating planet) gain eastward momentum while promoting broader, weaker westward circulation. Homogenization of potential vorticity is an important limit point, which many geophysical circulations achieve. This well-mixed state is found in subdomains of the terrestrial midlatitude oceans, the high-latitude circumpolar ocean, and episodically in the middle atmosphere. Homogenization expels potential vorticity gradients vertically to the top and bottom of the fluid, and sideways to the edges of flow domains or gyres; in both these ways is jet formation enhanced. PMID:12780108

Rhines, Peter B.

1994-06-01

79

Thrust bearing for turbocharger  

Microsoft Academic Search

A thrust bearing is described for sustaining the thrust load of the rotor shaft of a turbocharger, the thrust bearing having a first and second opposed side surface, comprising: A first groove formed in the first side surface of the thrust bearing for holding lubricating oil supplied to the bearing; at least one first oil passage extending from the groove

T. Tamura; N. Shibata; T. Kawakami

1987-01-01

80

Lifting Surface Theory for Thrust Augmenting Ejectors.  

National Technical Information Service (NTIS)

The circulation theory of airfoil lift has been applied to predict the static performance of thrust augmenting ejectors. The ejector shroud is considered to be 'flying' in the velocity field induced by the entrainment of the primary jets, so that the thru...

P. M. Bevilaqua

1982-01-01

81

vectors  

NSDL National Science Digital Library

The word vector comes from the Latin term vehere, to carry. In Biology, a vector is an agent which carries disease, such as a mosquito carrying infected blood from one patient to the next. In physics, a vector is a quantity which has both a magnitude and a direction associated with it. The most commonly used example of vectors in everyday life is velocity. When you drive your car, your speedometer tells you the speed of your car, but it doesn't tell you where you are going. The combination of both where you are going and how fast you are going there is your car's velocity.

Joiner, David; The Shodor Education Foundation, Inc.

82

Measuring axial pump thrust  

Microsoft Academic Search

An apparatus for measuring the hydraulic axial thrust of a pump under operation conditions is disclosed. The axial thrust is determined by forcing the rotating impeller off of an associated thrust bearing by use of an elongate rod extending coaxially with the pump shaft. The elongate rod contacts an impeller retainer bolt where a bearing is provided. Suitable measuring devices

Bernard P. Suchoza; Imre Becse

1988-01-01

83

Thrust stand for low-thrust liquid pulsed rocket engines  

Microsoft Academic Search

A thrust stand is developed for measuring the pulsed thrust generated by low-thrust liquid pulsed rocket engines. It mainly consists of a thrust dynamometer, a base frame, a connecting frame, and a data acquisition and processing system. The thrust dynamometer assembled with shear mode piezoelectric quartz sensors is developed as the core component of the thrust stand. It adopts integral

Qin Xing; Jun Zhang; Min Qian; Zhen-Yuan Jia; Bao-Yuan Sun

2010-01-01

84

Vectors  

NSDL National Science Digital Library

This web page introduces vectors as an extension of numbers having both magnitude and direction. The initial motivation is to describe velocity but the material includes a general discussion of vector algebra and an application to forces for the inclined plane. The page contains links to a related lesson plan and further opportunities to explore vectors. This is part of the extensive web site "From Stargazers to Starships", that uses space exploration and space science to introduce topics in physics and astronomy. Translations in Spanish and French are available.

Stern, David

2006-07-16

85

Jets of incipient liquids  

NASA Astrophysics Data System (ADS)

Jets of incipient water escaping into the atmosphere through a short channel are photographed. In some experiments. complete disintegration of the jet is observed. The relationship of this phenomenon with intense volume incipience is considered. The role of the Coanda effect upon complete opening of the jet is revealed. Measurement results of the recoil force R of the jets of incipient liquids are presented. Cases of negative thrust caused by the Coanda effect are noted. Generalization of experimental data is proposed.

Reshetnikov, A. V.; Mazheiko, N. A.; Skripov, V. P.

2000-05-01

86

Thrust bearing for turbocharger  

SciTech Connect

A thrust bearing is described for sustaining the thrust load of the rotor shaft of a turbocharger, the thrust bearing having a first and second opposed side surface, comprising: A first groove formed in the first side surface of the thrust bearing for holding lubricating oil supplied to the bearing; at least one first oil passage extending from the groove toward the axis of the rotor shaft; at least one second oil passage communicating with the first oil passage and having a plurality of oil holes connected thereto that extend respectively to a plurality of tapering land portions formed on the first and second side surfaces of the thrust bearing so that the axial thrust bearing clearance decreases in a direction of rotation of the shaft; a first and second leg portion defining a cut out portion formed exclusively in the lower end portion of the thrust bearing; a planar portion formed in the end surface of the thrust bearing along the first and second cut out portion and forming a portion of a closed loop; and a second groove formed between the planar portion and the surfaces on which the shaft bears wherein the oil holes are formed in proximity to a point of maximum thrust clearance of the tapering land portions.

Tamura, T.; Shibata, N.; Kawakami, T.

1987-01-27

87

Development of a polarization resolved spectroscopic diagnostic for measurements of the vector magnetic field in the Caltech coaxial magnetized plasma jet experiment.  

PubMed

In the Caltech coaxial magnetized plasma jet experiment, fundamental studies are carried out relevant to spheromak formation, astrophysical jet formation/propagation, solar coronal physics, and the general behavior of twisted magnetic flux tubes that intercept a boundary. In order to measure the spatial profile of the magnetic field vector for understanding the underlying physics governing the dynamical behavior, a non-perturbing visible emission spectroscopic method is implemented to observe the Zeeman splitting in emission spectra. We have designed and constructed a polarization-resolving optical system that can simultaneously detect the left- and right-circularly polarized emission. The system is applied to singly ionized nitrogen spectral lines. The magnetic field strength is measured with a precision of about ±13 mT. The radial profiles of the azimuthal and axial vector magnetic field components are resolved by using an inversion method. PMID:23464211

Shikama, T; Bellan, P M

2013-02-01

88

Jet Blast Hazards.  

National Technical Information Service (NTIS)

The report encompasses a broad review of hazards directly related to inadvertent use of jet thrust power and its adverse effects on other aircraft, airport-ramp personnel, passengers and airport equipment. These jet-blast hazards are illustrated by a repr...

1972-01-01

89

Aeroacoustics of hot jets  

Microsoft Academic Search

A systematic study has been undertaken to quantify the effect of jet temperature on the noise radiated by subsonic jets. Nozzles of different diameters were tested to uncover the effects of Reynolds number. All the tests were carried out at Boeing's Low Speed Aeroacoustic Facility, with simultaneous measurement of thrust and noise. It is concluded that the change in spectral

K. Viswanathan

2004-01-01

90

Variable thrust cartridge  

DOEpatents

The present invention is a variable thrust cartridge comprising a water-molten aluminum reaction chamber from which a slug is propelled. The cartridge comprises a firing system that initiates a controlled explosion from the reaction chamber. The explosive force provides a thrust to a slug, preferably contained within the cartridge.

Taleyarkhan, Rusi P. (Knoxville, TN)

2000-11-07

91

Axial Thrust Bearing.  

National Technical Information Service (NTIS)

The axial thrust bearing intended, for example, for a turbo-compressor used to supercharge an internal combustion engine, contains fixed and moving thrust elements in contact with the working shaft; it is distinguished by the fact that in order to increas...

L. A. Samarin S. T. Sharov V. A. Rakhmanov V. E. Vinyar Y. A. Trofimov

1971-01-01

92

MPD thrust chamber flow dynamics  

NASA Astrophysics Data System (ADS)

Flow within the thrust chamber of a Magnetoplasmadynamic (MPD) arcjet is examined experimentally and modeled with a 2-D magnetohydrodynamic code. Two quasi-steady MPD thrusters are considered under the same input conditions of current (21 kA) and total mass flow rate (0.006 kg/s, argon + 1.5 percent hydrogen). The arcjets have the same basic design, consisting of a central cathode, 3.8 cm diameter and 5 cm long, separated from a coaxial anode of equal length by a uniform gap of 2.3 cm. Two different mass injection arrangements are used (100 percent at mid-radius, and 50 percent at the cathode base, with the remainder at mid-radius). A new spectroscopic analysis procedure is developed that allows distributions of radial speed, heavy particle temperature and turbulent speed to be extracted from chordal measurements of light emission by the two species in the plasma flow. Good qualitative (and reasonable quantitative) agreement exists with distributions calculated by the MHD code, indicating that flow within the thrust chamber expands from an electromagnetically pumped plasma base (vs a pumped jet off the cathode tip). The significant variation of internal flow dynamics with mass injector arrangement implies the need for extensive experimentally validated code modeling in order to evaluate the potential performance of MPD thrusters.

1990-08-01

93

Jet-diffuser ejector - Attached nozzle design  

Microsoft Academic Search

Attached primary nozzles were developed to replace the detached nozzles of jet-diffuser ejectors. Slotted primary nozzles located at the inlet lip and injecting fluid normal to the thrust axis, and rotating the fluid into the thrust direction using the Coanda Effect were investigated. Experiments indicated excessive skin friction or momentum cancellation due to impingement of opposing jets resulted in performance

M. Alperin; J. J. Wu

1980-01-01

94

Classification of jet fuel properties by near-infrared spectroscopy using fuzzy rule-building expert systems and support vector machines.  

PubMed

Monitoring the changes of jet fuel physical properties is important because fuel used in high-performance aircraft must meet rigorous specifications. Near-infrared (NIR) spectroscopy is a fast method to characterize fuels. Because of the complexity of NIR spectral data, chemometric techniques are used to extract relevant information from spectral data to accurately classify physical properties of complex fuel samples. In this work, discrimination of fuel types and classification of flash point, freezing point, boiling point (10%, v/v), boiling point (50%, v/v), and boiling point (90%, v/v) of jet fuels (JP-5, JP-8, Jet A, and Jet A1) were investigated. Each physical property was divided into three classes, low, medium, and high ranges, using two evaluations with different class boundary definitions. The class boundaries function as the threshold to alarm when the fuel properties change. Optimal partial least squares discriminant analysis (oPLS-DA), fuzzy rule-building expert system (FuRES), and support vector machines (SVM) were used to build the calibration models between the NIR spectra and classes of physical property of jet fuels. OPLS-DA, FuRES, and SVM were compared with respect to prediction accuracy. The validation of the calibration model was conducted by applying bootstrap Latin partition (BLP), which gives a measure of precision. Prediction accuracy of 97 ± 2% of the flash point, 94 ± 2% of freezing point, 99 ± 1% of the boiling point (10%, v/v), 98 ± 2% of the boiling point (50%, v/v), and 96 ± 1% of the boiling point (90%, v/v) were obtained by FuRES in one boundaries definition. Both FuRES and SVM obtained statistically better prediction accuracy over those obtained by oPLS-DA. The results indicate that combined with chemometric classifiers NIR spectroscopy could be a fast method to monitor the changes of jet fuel physical properties. PMID:21073794

Xu, Zhanfeng; Bunker, Christopher E; Harrington, Peter de B

2010-11-01

95

Thrust stand for low-thrust liquid pulsed rocket engines  

NASA Astrophysics Data System (ADS)

A thrust stand is developed for measuring the pulsed thrust generated by low-thrust liquid pulsed rocket engines. It mainly consists of a thrust dynamometer, a base frame, a connecting frame, and a data acquisition and processing system. The thrust dynamometer assembled with shear mode piezoelectric quartz sensors is developed as the core component of the thrust stand. It adopts integral shell structure. The sensors are inserted into unique double-elastic-half-ring grooves with an interference fit. The thrust is transferred to the sensors by means of static friction forces of fitting surfaces. The sensors could produce an amount of charges which are proportional to the thrust to be measured. The thrust stand is calibrated both statically and dynamically. The in situ static calibration is performed using a standard force sensor. The dynamic calibration is carried out using pendulum-typed steel ball impact technique. Typical thrust pulse is simulated by a trapezoidal impulse force. The results show that the thrust stand has a sensitivity of 25.832 mV/N, a linearity error of 0.24% FSO, and a repeatability error of 0.23% FSO. The first natural frequency of the thrust stand is 1245 Hz. The thrust stand can accurately measure thrust waveform of each firing, which is used for fine control of on-orbit vehicles in the thrust range of 5-20 N with pulse frequency of 50 Hz.

Xing, Qin; Zhang, Jun; Qian, Min; Jia, Zhen-Yuan; Sun, Bao-Yuan

2010-09-01

96

Thrust stand for low-thrust liquid pulsed rocket engines.  

PubMed

A thrust stand is developed for measuring the pulsed thrust generated by low-thrust liquid pulsed rocket engines. It mainly consists of a thrust dynamometer, a base frame, a connecting frame, and a data acquisition and processing system. The thrust dynamometer assembled with shear mode piezoelectric quartz sensors is developed as the core component of the thrust stand. It adopts integral shell structure. The sensors are inserted into unique double-elastic-half-ring grooves with an interference fit. The thrust is transferred to the sensors by means of static friction forces of fitting surfaces. The sensors could produce an amount of charges which are proportional to the thrust to be measured. The thrust stand is calibrated both statically and dynamically. The in situ static calibration is performed using a standard force sensor. The dynamic calibration is carried out using pendulum-typed steel ball impact technique. Typical thrust pulse is simulated by a trapezoidal impulse force. The results show that the thrust stand has a sensitivity of 25.832 mV/N, a linearity error of 0.24% FSO, and a repeatability error of 0.23% FSO. The first natural frequency of the thrust stand is 1245 Hz. The thrust stand can accurately measure thrust waveform of each firing, which is used for fine control of on-orbit vehicles in the thrust range of 5-20 N with pulse frequency of 50 Hz. PMID:20887003

Xing, Qin; Zhang, Jun; Qian, Min; Jia, Zhen-yuan; Sun, Bao-yuan

2010-09-01

97

Vector Thrust Load Cell Feasibility Study.  

National Technical Information Service (NTIS)

This report describes the results of a research study and analysis of a 6-component force balance for testing rocket engines. The balance is essentially a self-contained, semi-portable structure of strain-gaged force links attached at the forward end of t...

R. W. Postma

1969-01-01

98

Longitudinal Double-Spin Asymmetry for Inclusive Jet Production in p-vector+p-vector Collisions at {radical}(s)=200 GeV  

SciTech Connect

We report a new STAR measurement of the longitudinal double-spin asymmetry A{sub LL} for inclusive jet production at midrapidity in polarized p+p collisions at a center-of-mass energy of {radical}(s)=200 GeV. The data, which cover jet transverse momenta 5

Abelev, B. I.; Barannikova, O.; Betts, R. R.; Callner, J.; Garcia-Solis, E.; Hofman, D. J.; Hollis, R. S.; Iordanova, A.; Suarez, M. C. [University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Aggarwal, M. M.; Bhati, A. K.; Kumar, A.; Pruthi, N. K.; Sharma, M. [Panjab University, Chandigarh 160014 (India); Ahammed, Z.; Chattopadhyay, S.; Das, D.; Dutta Mazumdar, M. R.; Ganti, M. S.; Ghosh, P. [Variable Energy Cyclotron Centre, Kolkata 700064 (India)] (and others)

2008-06-13

99

Finite-thrust optimization of interplanetary transfers of space vehicle with bimodal nuclear thermal propulsion  

Microsoft Academic Search

The nuclear thermal rocket (NTR) propulsion is one of the leading promising technologies for primary space propulsion for manned exploration of the solar system due to its high specific impulse capability and sufficiently high thrust-to-weight ratio. Another benefit of NTR is its possible bimodal design, when nuclear reactor is used for generation of a jet thrust in a high-thrust mode

Oleksii M. Kharytonov; Boris M. Kiforenko

2011-01-01

100

Flow measurements in a high pressure ratio thrust augmenting ejector  

Microsoft Academic Search

Pressure probing coupled with flow visualization was used to gain insight into the entrainment mechanisms occurring in an ejector duct with primary jet stagnation pressures up to 50 atmospheres. Variations in ejector thrust were matched by changes in the flow structure, involving unsteady phenomena which might be exploited to enhance mixing in certain specialized ejector applications.

S. A. Fisher; A. M. Abdel-Fattah

1987-01-01

101

Environmental Thrust Handbook.  

ERIC Educational Resources Information Center

|This handbook was prepared as a tool to assist U. S. Department of Agriculture (USDA) employees coordinate their resources and efforts to help people improve their environment. Twenty-two projects are outlined as potential environmental thrusts at the community level. It is the role of USDA employees to encourage and assist, in every way…

Department of Agriculture, Washington, DC.

102

Environmental Thrust Handbook.  

ERIC Educational Resources Information Center

This handbook was prepared as a tool to assist U. S. Department of Agriculture (USDA) employees coordinate their resources and efforts to help people improve their environment. Twenty-two projects are outlined as potential environmental thrusts at the community level. It is the role of USDA employees to encourage and assist, in every way possible,…

Department of Agriculture, Washington, DC.

103

Axisymmetric Coanda-assisted vectoring  

NASA Astrophysics Data System (ADS)

An experimental demonstration of a jet vectoring technique used in our novel spray method called Coanda-assisted Spray Manipulation (CSM) is presented. CSM makes use of the Coanda effect on axisymmetric geometries through the interaction of two jets: a primary jet and a control jet. The primary jet has larger volume flow rate but generally a smaller momentum flux than the control jet. The primary jet flows through the center of a rounded collar. The control jet is parallel to the primary and is adjacent to the convex collar. The Reynolds number range for the primary jet at the exit plane was between 20,000 and 80,000. The flow was in the incompressible Mach number range (Mach < 0.3). The control jet attaches to the convex wall and vectors according to known Coanda effect principles, entraining and vectoring the primary jet, resulting in controllable r - ? directional spraying. Several annular control slots and collar radii were tested over a range of momentum flux ratios to determine the effects of these variables on the vectored jet angle and spreading. Two and Three-component Particle Image Velocimetry systems were used to determine the vectoring angle and the profile of the combined jet in each experiment. The experiments show that the control slot and expansion radius, along with the momentum ratios of the two jets predominantly affected the vectoring angle and profile of the combined jets.

Allen, Dustin; Smith, Barton L.

2009-01-01

104

An experimental study of voice-coil driven synthetic jet propulsion for underwater vehicles  

Microsoft Academic Search

This paper investigates the thrust and flow structures produced by submerged synthetic jet actuators. Inspired by the propulsion methods of many sea creatures, such as jellyfish, squids, and salps; synthetic jets use vortex rings to create a net thrust. To assess the potential usability of these thrusters for propulsion and maneuvering of small underwater vehicles, a range of synthetic jet

A. M. Polsenberg-Thomas; Joel Burdick; Kamran Mohseni

2005-01-01

105

Rapidity correlations between high p{sub T} intermediate vector bosons and jets in {bar p}p collisions at {radical}s = 1.8 TeV  

SciTech Connect

D{O} has used W {yields} e{nu} and Z {yields} e{sup +}e{sup -} events produced in association with a high p{sub T}, jet to examine the effects of strong radiative corrections. We have compared the primary jet pseudorapidity distribution, as a function of reconstructed W or Z boson rapidity to leading order (LO) and Next-to-Leading order (NLO) QCD Monte Carlo generators, as well as a model based on extended color dipoles. We find that the primary jet is more central than either LO or NLO expectations. None of the Monte Carlo programs does a good job of predicting the shape of the jet distributions as a function of intermediate vector bosons rapidity.

Abachi, S.

1995-07-01

106

Development of a two-dimensional dual pendulum thrust stand for Hall thrusters  

SciTech Connect

A two-dimensional dual pendulum thrust stand was developed to measure thrust vectors (axial and horizontal (transverse) direction thrusts) of a Hall thruster. A thruster with a steering mechanism is mounted on the inner pendulum, and thrust is measured from the displacement between inner and outer pendulums, by which a thermal drift effect is canceled out. Two crossover knife-edges support each pendulum arm: one is set on the other at a right angle. They enable the pendulums to swing in two directions. Thrust calibration using a pulley and weight system showed that the measurement errors were less than 0.25 mN (1.4%) in the main thrust direction and 0.09 mN (1.4%) in its transverse direction. The thrust angle of the thrust vector was measured with the stand using the thruster. Consequently, a vector deviation from the main thrust direction of {+-}2.3 deg. was measured with the error of {+-}0.2 deg. under the typical operating conditions for the thruster.

Nagao, N.; Yokota, S.; Komurasaki, K.; Arakawa, Y. [Department of Aeronautics and Astronautics, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Advanced Energy, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Aeronautics and Astronautics, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2007-11-15

107

Characteristic jet engine parameters for project comparisons  

Microsoft Academic Search

Characteristic parameters for 98 jet engines are depicted in graphs and listed in tables. The main parameters considered are thrust, weight, specific fuel consumption, air mass flow rate, compression, pressure, ratio, diameter, and length.

Licklederer

1974-01-01

108

Jet-Diffuser Ejector - Attached Nozzle Design.  

National Technical Information Service (NTIS)

Attached primary nozzles were developed to replace the detached nozzles of jet-diffuser ejectors. Slotted primary nozzles located at the inlet lip and injecting fluid normal to the thrust axis, and rotating the fluid into the thrust direction using the Co...

M. Alperin J. J. Wu

1980-01-01

109

Study on the characteristics of supersonic Coanda jet  

NASA Astrophysics Data System (ADS)

Techniques using Coanda effect have been applied to the fluid control devices. In this field, experimental studies were so far performed for the spiral jet obtained by the Coanda jet issuing from a conical cylinder with an annular slit, thrust vectoring of supersonic Coanda jets and so on. It is important from the viewpoints of effective applications to investigate the characteristics of the supersonic Coanda jet in detail. In the present study, the effects of pressure ratios and nozzle configurations on the characteristics of the supersonic Coanda jet have been investigated experimentally by a schlieren optical method and pressure measurements. Furthermore, Navier-Stokes equations were solved numerically using a 2nd-order TVD finite-volume scheme with a 3rd-order three stage Runge-Kutta method for time integration. k - ? model was used in the computations. The effects of initial conditions on Coanda flow were investigated numerically. As a result, the simulated flow fields were compared with experimental data in good agreement qualitatively.

Matsuo, Shigeru; Setoguchi, Toshiaki; Kudo, Takemasa; Yu, Shen

1998-09-01

110

Optimal Thrust Development in Oscillating Foils with Application to Fish Propulsion  

Microsoft Academic Search

Oscillating foils produce thrust through the development of a jet-like average flow. It is found that such jets are convectively unstable with a narrow range of frequencies of maximum amplification, resulting in the formation of a staggered array of vortices with direction opposite to that of the classical Karman street. A stable co-existence of the jet profile and the large-scale

G. S. Triantafyllou; M. S. Triantafyllou; M. A. Grosenbaugh

1993-01-01

111

Flow Visualization and Interpretation of Visualization Data for Deflected Thrust V/STOL Nozzles.  

National Technical Information Service (NTIS)

Flow visualization studies were made for four deflected thrust nozzle models at subsonic speeds. Based on topological rules and the assumption that observed streaks constitute continuous vector fields, available visualization pictures are interpreted and ...

H. C. Kao P. L. Burstadt A. L. Johns

1984-01-01

112

Controls on thrust belt curvature, Wyoming-Idaho thrust belt  

SciTech Connect

Structural curvature in the northern part of the Wyoming-Idaho thrust belt (WITB) may be the result of either along-strike variations in pre-thrust stratigraphy or a buttress which physically concentrated shortening, or possibly both. Most thrust sheets of the WITB strike northward and were translated eastward, but in the Snake River Range (SRR) (the northernmost range in the WITB), structural strike curves from northward to nearly westward. Structural cross sections of the SRR are generally drawn in a radial pattern creating a volumetric imbalance in regional palinspastic restorations. Stratigraphic separation diagrams of major, through-going thrust faults in the SRR show extensive cut off in upper Paleozoic strata. New measured sections of upper Paleozoic stratigraphy at locations in several major thrust sheets of the WITB and in the foreland, new structural cross sections and mapping, and existing paleomagnetic data are used in a new interpretation of the origin of structural curvature in the WITB. Published paleomagnetic data require counterclockwise rotation of frontal thrust sheets along the northern boundary of the WITB, but no rotation of eastward-translated thrust sheets farther south along most of the WITB. Evidence for both a pre-existing west-trending depositional margin and rotation of frontal thrust sheets suggests that buttressing and modification of structural strike occurred along an oblique ramp where differences in stratigraphic thickness and possible pre-existing fault partitioning of the Paleozoic strata are localized.

Montgomery, J.M. Jr. (Univ. of Kentucky, Lexington, KY (United States). Dept. of Geological Sciences)

1993-04-01

113

Vacuum Thrust Optimised Expansion Deflection Nozzles  

NASA Astrophysics Data System (ADS)

ED nozzles have long been considered for launch vehicle applications, due to their postulated twin benefits of reduced length and altitude compensating capability. However, the difficulties involved in modelling the inviscid/viscous jet boundaries and associated flow phenomena during wake closure, have prevented the creation of a reliable method for the prediction of the performance characteristics of the type through atmospheric flight. However, if the operating regime of the nozzle is restricted to vacuum conditions (e.g. upper stages, and OTVs, etc), the wake region of the ED nozzle is permanently closed. Under these circumstances, the prediction of the pressure distribution along the viscous/inviscid flow boundary, and the complex interaction of the fluid flows during wake closure, becomes unnecessary. Therefore thrust calculation may be accomplished by conventional techniques, provided reliable methods are available for the prediction of the flow in the throat region (which may be arbitrarily displaced and inclined to the axis of revolution), and estimation of the pressure acting on the base of the central pintle. Prediction of ED nozzle throat flows has been accomplished by the use of CFD techniques, described in a previous paper. The analysis in this paper has been extended to complete nozzles by including a conventional method of characteristics based optimisation routine for the outer shroud contour, and a semi-empirical method for prediction of pintle base pressures. A brief parametric study is presented, outlining the effects of throat configuration (including throat wall radii, and radial displacement and inclination) on the performance of axisymmetric and planar ED nozzles under vacuum conditions. Whilst the method used for base pressure prediction requires several simplifying assumptions which affect the accuracy, results from an ongoing experimental program are reducing this uncertainty. Further as nozzles designed for vacuum operation are likely to have extremely high area ratios to maximise thrust coefficient, the relative magnitude of the pintle base pressure is small compared to the forces generated on the shroud, reducing the sensitivity of overall thrust calculations to errors in base pressure prediction. A comparison of thrust performance of bell and ED nozzles reveals that considerable reductions in length are possible, in the region of 30%. By implication this should result in a significant lowering of system mass. This conclusion is further supported by consideration of the unrealistic worst case scenario, which is the assumption of zero thrust contribution from the pintle. This analysis still produces length savings of over 20% when compared to conventional optimised bell nozzles.

Taylor, N. V.; Hempsell, C. M.

2002-01-01

114

Micro thrust and heat generator  

DOEpatents

A micro thrust and heat generator has a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator's ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachining techniques (LIGA).

Garcia, Ernest J. (Albuquerque, NM)

1998-01-01

115

Micro thrust and heat generator  

DOEpatents

A micro thrust and heat generator have a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator`s ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachining techniques (LIGA). 30 figs.

Garcia, E.J.

1998-11-17

116

Coanda Inlet/Jet Flap Diffuser Ejector.  

National Technical Information Service (NTIS)

The combination of a Coanda inlet and jet flap diffusion, for the achievement of high performance, low volume, thrust augmentation, has been investigated in a two-dimesnional experiment. The use of jet flap diffusion provides a mechanism for the achieveme...

M. Alperin

1972-01-01

117

Trajectories for missions of low-thrust spacecraft aimed at delivery of soil samples from main belt asteroids and Phobos  

NASA Astrophysics Data System (ADS)

Trajectories of spacecraft with electro-jet low-thrust engines are studied for missions planning to deliver samples of matter from small bodies of the Solar System: asteroids Vesta and Fortuna, and Martian moon Phobos. Flight trajectories are analyzed for the mission to Phobos, the limits of optimization of payload spacecraft mass delivered to it are determined, and an estimate is given to losses in the payload mass when a low-thrust engine with constant outflow velocity is used. The model of an engine with ideally regulated low thrust is demonstrated to be convenient for calculations and analysis of flight trajectories of a low-thrust spacecraft.

Akhmetshin, R. Z.; Efimov, G. B.; Eneev, T. M.

2009-02-01

118

THE EFFECTS OF WALL INCLINATION ON AN INCLINED OFFSET JET  

Microsoft Academic Search

There are numerous technological applications in which offset jets play an important role, such as entrainment and mixing processes in boiler and gas turbine combustion chambers, fuel injection systems, and thrust- augmenting ejectors for V\\/STOL aircraft. Although studies of both offset jets with zero angle of wall inclination and inclined wall jets (with no offset) using primarily pressure measurements and

Asghar Nasr

119

The Effect Of Counterflow On The Acoustic Characteristics Of A Mach 1.44 Rectangular Jet  

NASA Astrophysics Data System (ADS)

The application of counterflow around the periphery of a jet has been used to achieve elevated mixing levels in compressible shear layers and to provide fluidic thrust vector control of supersonic jets. Due to these benefits, an investigation is undertaken to determine the effect of counterflow on the acoustic properties of supersonic jets. Specifically, the aeroacousitc properties of a Mach 1.44 rectangular jet operating at on and off-design conditions are examined with several levels of counterflow. The acoustic measurements are obtained in the anechoic chamber of the High Speed Facility of the Fluid Mechanics Research Laboratory (FMRL) capable of providing cold and hot flow (up to 1000 deg. F). The preliminary results show that a change in both shock cell spacing and magnitude occurs when different levels of counterflow are applied to the jet. The modification of the shock associated noise and the overall sound pressure level suggests that the use of counterflow should be further explored as a potential noise suppression method for supersonic jets.

Washington, D.; Shih, C.; Alvi, F. S.; Krothapalli, A.

1996-11-01

120

Jet production in {gamma}{gamma} interactions at PEP  

SciTech Connect

We have used the TPC/Two-Gamma Facility at the SLAC e{sup +}e{sup {minus}} storage ring PEP to study the photon-photon reaction e{sup +}e{sup {minus}} {yields} e{sup +}e{sup {minus}} + hadrons, in both the single-tagged mode (one outgoing e{sup {plus_minus}} detected) and the untagged mode (neither e{sup {plus_minus}} detected). A thrust algorithm was used to find the jet axis in the hadronic center-of-mass, and this axis was used to calculate the transverse momentum with respect to the {gamma}{gamma} collision axis (p{sub t}). The (preliminary) p{sub t} and thrust distributions of both tagged and untagged data are well-described by the predictions of vector meson dominance (VDM) at low p{sub t}. For 3 < p{sub t} < 4.5 GeV, the tagged data are consistent with the prediction of the Quark Parton Model (QPM). In the intermediate region -- 1.5 < p{sub t} < 3 GeV -- an excess of events is seen in both samples. The p{sub t} and event topology of these excess events are compared to a 3-jet model based on QCD.

TPC /Two-Gamma Collaboration

1988-12-31

121

Lateral Dampers for Thrust Bearings.  

National Technical Information Service (NTIS)

The development of lateral damping schemes for thrust bearings was examined, ranking their applicability to various engine classes, selecting the best concept for each engine class and performing an in-depth evaluation. Five major engine classes were cons...

D. H. Hibner D. R. Szafir

1985-01-01

122

Pneumatically actuated micromachined synthetic jet modulators  

Microsoft Academic Search

Results presented in the synthetic jet literature have focused on the demonstration of and application of one or more single-orifice synthetic jet actuators in jet vectoring and other aerodynamic applications. For these applications, amplitude and phase modulation techniques are often used in conjunction with the oscillatory nature of the synthetic jet flow to achieve the desired results. In this work

David J. Coe; Mark G. Allen; Christopher S. Rinehart; Ari Glezer

2006-01-01

123

Prediction of thrusting sequences in accretionary wedges  

Microsoft Academic Search

The main objective is to determine the three stages of the life of a thrust in an accretionary wedge which are the onset of thrusting along its ramp, the development with the construction of the relief, and the arrest because of the onset of another thrusting event. A simple kinematics is proposed for the geometry of the developing thrust fold

N. Cubas; Y. M. Leroy; B. Maillot

2008-01-01

124

Finite-thrust optimization of interplanetary transfers of space vehicle with bimodal nuclear thermal propulsion  

NASA Astrophysics Data System (ADS)

The nuclear thermal rocket (NTR) propulsion is one of the leading promising technologies for primary space propulsion for manned exploration of the solar system due to its high specific impulse capability and sufficiently high thrust-to-weight ratio. Another benefit of NTR is its possible bimodal design, when nuclear reactor is used for generation of a jet thrust in a high-thrust mode and (with an appropriate power conversion system) as a source of electric power to supply the payload and the electric engines in a low-thrust mode. The model of the NTR thrust control was developed considering high-thrust NTR as a propulsion system of limited power and exhaust velocity. For the proposed model the control of the thrust value is accomplished by the regulation of reactor thermal power and propellant mass flow rate. The problem of joint optimization of the combination of high- and low-thrust arcs and the parameters of bimodal NTR (BNTR) propulsion system is considered for the interplanetary transfers. The interplanetary trajectory of the space vehicle is formed by the high-thrust NTR burns, which define planet-centric maneuvers and by the low-thrust heliocentric arcs where the nuclear electric propulsion (NEP) is used. The high-thrust arcs are analyzed using finite-thrust approach. The motion of the corresponding dynamical system is realized in three phase spaces concerning the departure planet-centric maneuver by means of high-thrust NTR propulsion, the low-thrust NEP heliocentric maneuver and the approach high-thrust NTR planet-centric maneuver. The phase coordinates are related at the time instants of the change of the phase spaces due to the relations between the space vehicle masses. The optimal control analysis is performed using Pontryagin's maximum principle. The numerical results are analyzed for Earth-Mars "sprint" transfer. The optimal values of the parameters that define the masses of NTR and NEP subsystems have been evaluated. It is shown that the low-thrust NEP subsystem with Brayton cycle power conversion system is preferable in comparison with NEP subsystem with thermoemission power conversion system.

Kharytonov, Oleksii M.; Kiforenko, Boris M.

2011-08-01

125

Parameters Governing Separation Control with Sweeping Jet Actuators  

NASA Astrophysics Data System (ADS)

Parameters governing separation control with sweeping jet actuators over a deflected flap are investigated experimentally on a generic "Multiple Flap Airfoil" (MFA). The model enables an extensive variation of geometric and aerodynamic parameters to aid the scaling of this novel flow control method to full-size applications. Sweeping jets exit from discrete, millimeter-scale nozzles distributed along the span and oscillate from side-to-side. The sweeping frequency is almost linearly dependent on the supplied flowrate per actuator. The measured thrust exerted by a row of actuators agrees well with vectored momentum calculations. Frequency and thrust measurements suggest that the jet velocity is limited to subsonic speeds and that any additional increase in flowrate causes internal choking of the flow. Neither the flowrate nor the momentum input is found to be a sole parameter governing the lift for varying distance between adjacent actuators. However, the product of the mass flow coefficient and the square root of the momentum coefficient collapses the lift onto a single curve regardless of the actuator spacing. Contrary to other actuation methods, separation control with sweeping jets does not exhibit any hysteresis with either momentum input or flap deflection. A comparison between sweeping and non-sweeping jets illustrates the superior control authority provided by sweeping jets. Surface flow visualization on the flap suggests the formation of counter-rotating pairs of streamwise vortices caused by the interaction of neighboring jets. The actuation intensity required to attach the flow increases with increasing downstream distance from the main element's trailing edge and increasing flap deflection. No obvious dependence of the ideal actuation location on actuator spacing, flap deflection, angle of attack, or actuation intensity is found within the tested range. Comparisons between experimental and numerical results reveal that the inviscid flow solution appears to be a suitable predictor for the effectively and efficiently obtainable lift of a given airfoil configuration. The flap size affects the achievable lift, the accompanying drag, and the required flap deflection and actuation intensity. By controlling separation, the range of achievable lift coefficients is doubled without significant penalty in drag even when considering a safety margin for the maximum applicable incidence.

Woszidlo, Rene

126

Thrust Coefficients, Thrust Deflection Angles, and Nondimensional Moments for Nozzles with Oblique Exit Planes.  

National Technical Information Service (NTIS)

Nozzles with oblique exit planes, scarfed nozzles, are encountered in aerospace applications such as reaction control and thrust reversal systems. This document provides thrust coefficient, thrust deflection angle, and nondimensional turning moment data f...

W. W. Phillips R. A. Fiedler R. G. Hopcroft

1968-01-01

127

Teach Engineering: May the Force Be With You: Thrust  

NSDL National Science Digital Library

This lesson is the third of a four-part unit for Grades 5-8 on the key forces in flight: lift, weight, thrust, and drag. In this lesson students will study how propellers and jet turbines generate thrust. It focuses on Newton's Third Law of Motion, which states that for every action there is an equal and opposite reaction. The lesson includes objectives, warm-up questions, background information for teachers, assessment questions, classroom activity, and web-based reference material. TeachEngineering is a Pathway project of the National Science Digital Library. It provides a large collection of teacher-tested, research-based content for K-12 teachers to connect real-world experiences with curricular content.

2011-10-10

128

Numerical investigation of the thrust efficiency of a laser-propelled vehicle  

NASA Astrophysics Data System (ADS)

The flow situation for a thruster propelled by ablated gas which is energized by a laser pulse is numerically simulated. The flow is axisymmetric and nonsteady, and is assumed to be inviscid due to its high Reynolds number. The high pressure expansion of the laser heated gas generated thrust as it pushes against the vehicle. Gas expansion lateral to the thrust vector causes performance to decrease. The vehicle geometry and the laser pulse characteristics determine the degree to which the flow is one dimensional. As the thruster's parameters are varied, its impulse is calculated and compared to the limiting impulse of a one-dimensional system, and thus the thrust efficiency is computed.

Mulroy, James Randolph

1991-05-01

129

Thrust aided sub-orbits  

Microsoft Academic Search

A discussion on thrust assisted sub-orbits is presented. This operation may be considered as a candidate means for providing station-keeping, for the interrogation of circulating satellites, and as an operational maneuver for pick-up, launch and\\/or inspection of experiment modules (and the like) from (say) the SHUTTLE spacecraft.

J. B. Eades

1977-01-01

130

MPD Thrust Chamber Flow Dynamics.  

National Technical Information Service (NTIS)

Flow within the thrust chamber of an MPD arcjet is examined experimentally and modeled with a two-dimensional MHD code. Two quasi-steady MPD thrusters are considered under the same input conditions of current (21 kA) and total mass flow rate (0.006 kg/s, ...

1990-01-01

131

Another Look at Rocket Thrust  

ERIC Educational Resources Information Center

|Rocket propulsion is often introduced as an example of Newton's third law. The rocket exerts a force on the exhaust gas being ejected; the gas exerts an equal and opposite force--the thrust--on the rocket. Equivalently, in the absence of a net external force, the total momentum of the system, rocket plus ejected gas, remains constant. The law of…

Hester, Brooke; Burris, Jennifer

2012-01-01

132

Thermal effects of thrust faulting  

Microsoft Academic Search

Calculations based on simple models of overthrust sheets in crystalline basement rocks show that significant thermal effects may result from their movements. If rates are sufficiently high (e.g. plate tectonic rates), the thrust sheets sufficiently thick (5, 10 and 15 km are modelled here), the distances moved sufficiently large, and for reasonable values of the coefficient of friction along the

Jon Brewer

1981-01-01

133

Debris Catcher for Thrust Temination Ports.  

National Technical Information Service (NTIS)

The patent application concerns an apparatus to reduce the degree of contamination in front of a solid propellant rocket motor following actuation of thrust termination devices. By erecting a debris catcher over the ports through which the thrust terminat...

J. D. Elias

1975-01-01

134

Experimental Study of Thrust Augmenting Ejectors.  

National Technical Information Service (NTIS)

An automated thrust augmentation data acquisition facility was designed and constructed. The facility provides the capability of measuring thrust augmentation ratio and mass flow augmentation ratio. A three dimensional graphics plot of exit flow is provid...

W. D. Lewis

1983-01-01

135

Pulsed Thruster Thrust Stand Measurement Evaluations  

Microsoft Academic Search

This paper presents a numerical analysis of thrust stand response during pulsed thruster operation. The system model incorporates an underdamped displacement-type thrust stand under a periodic, impulsive load. Analytic and numerical methods are used to examine thrust stand measurement characteristics during simulated operation. Displacement oscillation characteristics as a function of damping coefficient (alpha) and the ratio (tau) between the time

Keith A. McFall; G. G. Spanjers; J. H. Schilling

1998-01-01

136

Evaluation Report: AGARD Fluid Dynamics Panel Symposium on Fluid Dynamics of Jets with Application to V\\/STOL  

Microsoft Academic Search

Topics covered include: (1) jet interactions with neighboring surfaces; (2) jet structure and development; (3) wind tunnel simulation of flow field, forces moments; (4) injection and thrust augmentation; (5) theoretical models and their assessments; (6) two dimensional wall jets; and (7) the use of a tracer gas method for measuring entrainment of an axisymmetric free jet. Conclusions of a panel

B. M. Spee

1982-01-01

137

Thrust aided sub-orbits  

Microsoft Academic Search

A discussion on thrust assisted sub-orbits is presented. This operation may be considered as a candidate means for providing station-keeping, for the interrogation of circulating satellites, and as an operational maneuver for pick-up, launch and\\/or inspection of experiment modules (and the like) from (say) the SHUTTLE spacecraft. Examples, drawn from theoretical developments, are presented. These describe both the requirements and

J. B. Eades Jr.

1977-01-01

138

Investigation of Acoustic Interactions in Jet Thrust Augmenting Ejectors.  

National Technical Information Service (NTIS)

The performance of a constant area rectangular ejector with varying mixing length was investigated to determine the aeroacoustics interaction effects. The rectangular ejector investigation was conducted in two phases. The phase one investigation involved ...

J. R. Campbell K. D. Korkan H. Viets

1981-01-01

139

Crystalline thrust sheets: characteristics and mechanics  

SciTech Connect

Crystalline thrust sheets (CTS) are those partially or wholly composed of metamorphic and/or igneous rocks. They have been known for more than a century. People have recognized several types: 2) thin-skinned basement-cover sheets; 2) ophiolites; 3) tectonic slides; 4) basement uplifts; and 5) composite thrust sheets. The overthrust index ratio, B, may be obtained from dividing the total estimated displacement on CTS by the distance from the zero milligal contour on the prominent gravity gradient in an orogen, to the last thrust in the foreland. A fundamental property of CTS is the largest crystalline thrust sheet is always larger than the largest foreland thrust sheet in the same orogen, a property doubtlessly related to the relative strengths. Thicknesses of CTS are thus determined by the thermal flux through the crust. A mechanical model primarily for types 2 and 5 CTS relates cross-strike width (x) of thrust sheets to given values of tectonic compressive stress (sigma/sub c/), friction (tau/sub B/) and slope (..cap alpha..) of the basal thrust, and thrust sheet thickness (t). It requires low values of friction near 15 MPa and dips of 1 degree, based on observed thrust sheet widths and thicknesses, and assumes tectonic compression near 50 MPa. A mechanical model is provided for these thrust sheets. The equation can be used to relate observational data from deeply eroded ancient orogens to processes active during emplacement of CTS.

Hatcher, R.D. Jr.; Williams, R.T.

1985-01-01

140

Thrust generator for boring tools  

SciTech Connect

The present invention provides an electrically powered system for advancing a rotary boring tool in situations where the inclination of the bore hole is such that the force of gravity does not provide sufficient forward thrust. One or more marine screw propellers are rotated by the motor which itself is restrained from rotation by being fixedly connected to a flexible, twist resistant conduit for conducting the drilling fluid and electric power from the surface. The system may also provide for different rotative speeds for propeller and bit and for counter-rotating propellers to minimize torque forces on the conduit.

Dismukes, N.B.

1984-03-13

141

Low Thrust Orbital Maneuvers Using Ion Propulsion  

NASA Astrophysics Data System (ADS)

Low-thrust maneuver options, such as electric propulsion, offer specific challenges within mission-level Modeling, Simulation, and Analysis (MS&A) tools. This project seeks to transition techniques for simulating low-thrust maneuvers from detailed engineering level simulations such as AGI's Satellite ToolKit (STK) Astrogator to mission level simulations such as the System Effectiveness Analysis Simulation (SEAS). Our project goals are as follows: A) Assess different low-thrust options to achieve various orbital changes; B) Compare such approaches to more conventional, high-thrust profiles; C) Compare computational cost and accuracy of various approaches to calculate and simulate low-thrust maneuvers; D) Recommend methods for implementing low-thrust maneuvers in high-level mission simulations; E) prototype recommended solutions.

Ramesh, Eric

2011-10-01

142

A study of variable thrust, variable specific impulse trajectories for solar system exploration  

NASA Astrophysics Data System (ADS)

A study has been performed to determine the advantages and disadvantages of variable thrust and variable Isp (specific impulse) trajectories for solar system exploration. There have been several numerical research efforts for variable thrust, variable Isp, power-limited trajectory optimization problems. All of these results conclude that variable thrust, variable Isp (variable specific impulse, or VSI) engines are superior to constant thrust, constant Isp (constant specific impulse; or CSI) engines. However, most of these research efforts assume a mission from Earth to Mars, and some of them further assume that these planets are circular and coplanar. Hence they still lack the generality. This research has been conducted to answer the following questions: (1) Is a VSI engine always better than a CSI engine or a high thrust engine for any mission to any planet with any time of flight considering lower propellant mass as the sole criterion? (2) If a planetary swing-by is used for a VSI trajectory, is the fuel savings of a VSI swing-by trajectory better than that of a CSI swing-by or high thrust swing-by trajectory? To support this research, an unique, new computer-based interplanetary trajectory calculation program has been created. This program utilizes a calculus of variations algorithm to perform overall optimization of thrust, Isp, and thrust vector direction along a trajectory that minimizes fuel consumption for interplanetary travel. It is assumed that the propulsion system is power-limited, and thus the compromise between thrust and Isp is a variable to be optimized along the flight path. This program is capable of optimizing not only variable thrust trajectories but also constant thrust trajectories in 3-D space using a planetary ephemeris database. It is also capable of conducting planetary swing-bys. Using this program, various Earth-originating trajectories have been investigated and the optimized results have been compared to traditional CSI and high thrust trajectory solutions. Results show that VSI rocket engines reduce fuel requirements for any mission compared to CSI rocket engines. Fuel can be saved by applying swing-by maneuvers for VSI engines; but the effects of swing-bys due to VSI engines are smaller than that of CSI or high thrust engines.

Sakai, Tadashi

143

Thrust control system design of ducted rockets  

NASA Astrophysics Data System (ADS)

The investigation of the thrust control system is aroused by the need for propulsion system of ducted rockets. Firstly the dynamic mathematical models of gas flow regulating system, pneumatic servo system and ducted rocket engine were established and analyzed. Then, to conquer the discussed problems of thrust control, the idea of information fusion was proposed to construct a new feedback variable. With this fused feedback variable, the thrust control system was designed. According to the simulation results, the introduction of the new fused feedback variable is valid in eliminating the contradiction between rapid response and stability for the thrust control system of ducted rockets.

Chang, Juntao; Li, Bin; Bao, Wen; Niu, Wenyu; Yu, Daren

2011-07-01

144

Development and test of electromechanical actuators for thrust vector control  

Microsoft Academic Search

A road map of milestones toward the goal of a full scale Redesigned Solid Rocket Motor\\/Flight Support Motor (RSRM\\/FSM) hot fire test is discussed. These milestones include: component feasibility, full power system demonstration, SSME hot fire tests, and RSRM hot fire tests. The participation of the Marshall Space Flight Center is emphasized.

Rae A. Weir; John R. Cowan

1993-01-01

145

Jet noise from ultrahigh bypass turbofan engines  

Microsoft Academic Search

Modern commercial jet transport aircraft are powered by turbofan engines. Thrust from a turbofan engine is derived in part from the exhaust of a ducted fan, which may or may not be mixed with the core exhaust before exiting the nacelle. The historical trend has been toward ever higher bypass ratios (BPRs). The BPR is the ratio of air mass

Joe W. Posey; Thomas D. Norum; Martha C. Brown; Thonse R. S. Bhat

2002-01-01

146

Libby thrust belt and adjacent structures - new factors to consider in thrust tectonics of northwestern Montana  

Microsoft Academic Search

About 40 mi (65 km) west of the Rocky Mountain trench and at least 9 mi (15 km) above the sole detachment of the Rocky Mountain thrust belt is a zone of Cretaceous-Tertiary thrust faults up to 25 mi (40 km) wide in middle Proterozoic and Cambrian rocks. This zone (the Libby thrust belt) extends northward from the Lewis and

J. E. Harrison; E. R. Cressman

1985-01-01

147

Angular distribution of thrust axis with power-suppressed contribution in e + e - annihilation  

NASA Astrophysics Data System (ADS)

Structure function of e + e - ? hadrons cross section proportional to the longitudinal part of the hadron tensor is power suppressed with respect to an event shape variable in the two-jet region. In the SCET framework, we study the event shape distribution for this structure function to NLL level of accuracy. As, a result we obtain the angular distribution of hadron jets as a function of the thrust, in the two jet region. We further examine effects of non-perturbative hadronization corrections by adopting a shape function that reproduce the observed event shape distributions. Impacts of our findings on the electroweak measurements via the jet angular forward-backward asymmetry are discussed.

Hagiwara, Kaoru; Kirilin, Grisha

2010-10-01

148

Measuring Model Rocket Engine Thrust Curves  

ERIC Educational Resources Information Center

|This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…

Penn, Kim; Slaton, William V.

2010-01-01

149

Effect of Boundary Layer on Thrust Deduction.  

National Technical Information Service (NTIS)

Methods of computing thrust deduction usually ignore viscous effects and assume that the flow field of the ship and propeller is irrotational. The present work was undertaken in order to compare the computed values of the thrust deduction with and without...

S. P. G. Dinavahi L. Landweber

1981-01-01

150

Flow Visualization in a Pocketed Thrust Washer  

Microsoft Academic Search

The objectives of this study were to experimentally and numerically investigate oil flow in surface-pocketed thrust washers. In order to achieve the experimental aspects of this investigation, a thrust washer test rig was designed and developed to visualize the lubricant flow at the contact interface. A novel approach for creating the pockets was developed to allow optical inspection of lubricant

Andrew T. Cross; Farshid Sadeghi; Lijun Cao; Richard G. Rateick Jr; Scott Rowan

2012-01-01

151

Current Techniques for Thrust Measurement at PERME Westcott.  

National Technical Information Service (NTIS)

Techniques are described for the measurement of axial thrust and thrust alignment of rocket motors. The dynamic response of systems is also considered and methods of evaluating errors derived. A ballistic technique for recording total impulse and thrust/t...

D. S. Dean

1978-01-01

152

Boundary Layer Influence on Supersonic Jet\\/Cross-Flow Interaction in Hypersonic Flow  

Microsoft Academic Search

\\u000a Supersonic lateral jets are a convenient method for aerodynamic steering of bodies flying at hypersonic speeds. An accurate\\u000a prediction of the resulting aerodynamic force is difficult, because the flowfield around such a jet in a hypersonic cross-flow\\u000a is quite complex. In addition to the jet thrust a considerable pressure load on the body earl be generated by the jet\\/cross-flow\\u000a interaction.

M. Havermaiin; F. Seiler

153

Extending acoustic data measured with small-scale supersonic model jets to practical aircraft exhaust jets  

Microsoft Academic Search

Modern military aircraft jet engines are designed with variable geometry nozzles to provide optimum thrust in different operating conditions within the flight envelope. However, the acoustic measurements for such nozzles are scarce, due to the cost involved in making full-scale measurements and the lack of details about the exact geometry of these nozzles. Thus the present effort at The Pennsylvania

Ching-Wen Kuo

2010-01-01

154

Low thrust chemical rocket technology  

NASA Astrophysics Data System (ADS)

An on-going technology program to improve the performance of low thrust chemical rockets for spacecraft on-board propulsion applications is reviewed. Improved performance and lifetime is sought by the development of new predictive tools to understand the combustion and flow physics, introduction of high temperature materials and improved component designs to optimize performance, and use of higher performance propellants. Improved predictive technology is sought through the comparison of both local and global predictions with experimental data. Predictions are based on both the RPLUS Navier-Stokes code with finite rate kinetics and the JANNAF methodology. Data were obtained with laser-based diagnostics along with global performance measurements. Results indicate that the modeling of the injector and the combustion process needs improvement in these codes and flow visualization with a technique such as 2-D laser induced fluorescence (LIF) would aid in resolving issues of flow symmetry and shear layer combustion processes. High temperature material fabrication processes are under development and small rockets are being designed, fabricated, and tested using these new materials. Rhenium coated with iridium for oxidation protection was produced by the Chemical Vapor Deposition (CVD) process and enabled an 800 K increase in rocket operating temperature. Performance gains with this material in rockets using Earth storable propellants (nitrogen tetroxide and monomethylhydrazine or hydrazine) were obtained through component redesign to eliminate fuel film cooling and its associated combustion inefficiency while managing head end thermal soakback. Material interdiffusion and oxidation characteristics indicated that the requisite lifetimes of tens of hours were available for thruster applications. Rockets were designed, fabricated, and tested with thrusts of 22, 62, 440 and 550 N. Performance improvements of 10 to 20 seconds specific impulse were demonstrated. Higher performance propellants were evaluated: Space storable propellants, including liquid oxygen (LOX) as the oxidizer with nitrogen hydrides or hydrocarbon as fuels. Specifically, a LOX/hydrazine engine was designed, fabricated, and shown to have a 95 pct theoretical c-star which translates into a projected vacuum specific impulse of 345 seconds at an area ratio of 204:1. Further performance improvment can be obtained by the use of LOX/hydrogen propellants, especially for manned spacecraft applications, and specific designs must be developed and advanced through flight qualification.

Schneider, Steven J.

1992-11-01

155

Collar nut and thrust ring  

DOEpatents

A collar nut comprises a hollow cylinder having fine interior threads at one end for threadably engaging a pump mechanical seal assembly and an inwardly depending flange at the other end. The flange has an enlarged portion with a groove for receiving an O-ring for sealing against the intrusion of pumpage from the exterior. The enlarged portion engages a thrust ring about the pump shaft for crushing a hard O-ring, such as a graphite O-ring. The hard O-ring seals the interior of the mechanical seal assembly and pump housing against the loss of lubricants or leakage of pumpage. The fine threads of the hollow cylinder provide the mechanical advantage for crushing the hard O-ring evenly and easily with a hand tool from the side of the collar nut rather than by tightening a plurality of bolts from the end and streamlines the exterior surface of the mechanical seal. The collar nut avoids the spatial requirements of bolt heads at the end of a seal and associated bolt head turbulence. 4 figs.

Lowery, G.B.

1989-04-20

156

Collar nut and thrust ring  

DOEpatents

A collar nut comprises a hollow cylinder having fine interior threads at one end for threadably engaging a pump mechanical seal assembly and an inwardly depending flange at the other end. The flange has an enlarged portion with a groove for receiving an O-ring for sealing against the intrusion of pumpage from the exterior. The enlarged portion engages a thrust ring about the pump shaft for crushing a hard O-ring, such as a graphite O-ring. The hard O-ring seals the interior of the mechanical seal assembly and pump housing against the loss of lubricants or leakage of pumpage. The fine threads of the hollow cylinder provide the mechanical advantage for crushing the hard O-ring evenly and easily with a hand tool from the side of the collar nut rather than by tightening a plurality of bolts from the end and streamlines the exterior surface of the mechanical seal. The collar nut avoids the spatial requirements of bolt heads at the end of a seal and associated bolt head turbulence.

Lowery, Guy B. (Aiken, SC)

1991-01-01

157

Fold–thrust styles in the Absaroka thrust sheet, Caribou National Forest area, Idaho–Wyoming thrust belt  

Microsoft Academic Search

The Bear Creek, Big Elk and Black Mountain anticlines are macroscopic structures located in the hanging wall of the Absaroka thrust within the Idaho–Wyoming fold–thrust belt. Structural mapping of the area was conducted by draping existing geologic maps and digital orthophotos over digital elevation models (DEM) to obtain a three-dimensional perspective of the area. The map was further refined by

Subhotosh Banerjee; Shankar Mitra

2005-01-01

158

Computational investigation on infrared radiation characteristic for two-dimensional vectoring nozzles with fluidic injection  

Microsoft Academic Search

Relative to the thrust vectoring nozzle by mechanical means, fluidic injection vectoring nozzle outshines on the strength of uncomplicated structure, light weight and low cost. Research on infrared characteristic of fluidic injection vectoring nozzles is highly vital for nozzle technology development and military application. Numerical simulation for infrared characteristic of the two-dimensional fluidic injection vectoring nozzles was conducted employing self-developed

Guanqun Kang; Qiang Wang

2011-01-01

159

Entrainment and Mixing in Thrust Augmenting Ejectors.  

National Technical Information Service (NTIS)

Experiments have been performed with subsonic and underexpanded choked two-dimensional primary nozzle ejector flow system without diffusion to evaluate the role of entrainment and mixing in thrust augmentation. Two-component Laser Doppler velocity measure...

L. Bernal V. Sarohia

1982-01-01

160

An experimental study of thrust augmenting ejectors  

NASA Astrophysics Data System (ADS)

An automated thrust augmentation data acquisition facility was designed and constructed. The facility provides the capability of measuring thrust augmentation ratio and mass flow augmentation ratio. A three dimensional graphics plot of exit flow is provided for flow analysis. Tests were conducted on a 4.4 in. diameter circular ejector, with eight primary nozzles mounted symmetrically along the perimeter of the inlet. A fixed ejector geometry was used. The ratio of mixing chamber area to diffuser exit area was 1.88. The fluid injection angle, measured from a line perpendicular to the ejector centerline, was varied and the thrust augmentation and mass flow augmentation ratios calculated. Both thrust augmentation and mass flow augmentation increased with fluid injection angle to the stall point where both decreased. Axial flow symmetry of primary air was found to affect stall along diffuser walls.

Lewis, W. D.

1983-12-01

161

Structural evolution of a thrust-related fold system in the Lewis thrust plate, northwestern Montana  

SciTech Connect

In order to understand interactions between motion along thrusts and the associated style of deformation and strain distribution in their hangingwalls, geologic mapping and strain measurements were conducted in an excellently exposed thrust-related fold system in the Lewis thrust plate, northwestern Montana. This system consists of (1) an E-directed basal thrust (the Gunsight thrust) that has a flat-ramp geometry and a slip of about 3.5 km, (2) an E-verging asymmetric anticline with its nearly vertical forelimb truncated by the basal thrust from below, (3) a 4-km wide fold belt, the frontal fold complex, that lies directly in front of the E-verging anticline, (4) a W-directed bedding-parallel fault (the Mt. Thompson fault) that bounds the top of the frontal fold belt and separates it from the undeformed to broadly folded strata above, and (5) regionally developed, W-dipping spaced cleavage. Strain in the thrust-related fold system was determined by the preferred orientation of mica and chlorite grains. The direction and magnitude of the post-compaction strain varies from place to place. Strains in the forelimb of the hangingwall anticline imply bedding-parallel thinning at some localities and thickening at others. The inhomogeneity may be caused by the development of thrusts and folds. Strain in the backlimb of the hangingwall anticline implies bedding-parallel stretching in the thrust transport direction. This could be the effect of bending as the E-verging anticline was tightened and transported across the basal thrust ramp. Strain measured next to the Gunsight thrust again indicates locally varying shortening and extension in the transport direction, perhaps in response to inhomogeneous friction on the fault or else to a history of alternating strain hardening and softening in the basal thrust zone.

Yin, A.; Oertel, G. (Univ. of California, Los Angeles, CA (United States). Dept. of Earth and Space Sciences)

1992-01-01

162

Shedding light on hydroelectric thrust bearing problems  

SciTech Connect

Why did thrust bearing failures, so rare in hydro plants built in the first decades of this century, increase greatly during and after World War II Engineers have found that modern manufacturing techniques created problems as well as solutions. Two primary reasons for failure are a too smooth surface finish, and an oil film force that causes the split runner in the thrust bearings to slip, which results in fretting.

Baudry, R.A.; Rielly, D.H. (ElectroMechanical Engineering Associates, Pittsburgh, PA (United States))

1991-07-01

163

Resummation of thrust distributions in DIS  

NASA Astrophysics Data System (ADS)

We calculate the resummed distributions for the thrust in DIS in the limit Trightarrow1. Two variants of the thrust are considered: that normalised to Q/2, and that normalised to the energy in the current hemisphere. The results expanded to second order are compared to predictions from the Monte Carlo programs DISENT and DISASTER++. A prescription is given for matching the resummed expressions with the full fixed order calculation.

Antonelli, Vito; Dasgupta, Mrinal; Salam, Gavin P.

2000-02-01

164

Axial thrust behavior in LOX-pump of rocket engine  

Microsoft Academic Search

The LOX pump of the first stage of the H-2 rocket, the next generation of large launch vehicle in Japan, has shown fairly good axial thrust performance. However, the behavior of the axial thrust is not well known because of the complicated mechanism of the thrust-balancing device. In order to elucidate the flow characteristic of the complicated thrust balancing device

Junichi Kurokawa; Kenjiro Kamijo; Takashi Shimura

1994-01-01

165

Autonomous low-thrust guidance: application to SMART-1 and BepiColombo.  

PubMed

Several techniques have been developed to obtain optimum trajectories with low-thrust propulsion. However, few low-thrust guidance schemes have been investigated to fly the reference optimum trajectories. The guidance algorithm successfully employed in the DeepSpace1 mission was the first approximation through the presented guidance schemes, valid for various interplanetary low-thrust trajectories, independently of the optimization technique they result from. A method is presented to transform any given thrust profile to a thrust law defined by a finite set of control variables. This law allows the definition of a control vector to be optimized for the guidance purposes. Simulations were carried out to compare the performances of the algorithms to very different missions, such as SMART-1 and BepiColombo. The good performance of the enhanced guidance schemes prove the generic applicability of the algorithm. Parametric analysis allows the assessment of stability and robustness of the schemes and the sensitivity to certain parameters. Table. PMID:15220153

Gil-Fernández, Jesús; Graziano, Mariella; Gómez-Tierno, M A; Milic, E

2004-05-01

166

Search for 3rd Generation Vector Leptoquarks in the Di-tau Di-jet Channel in Proton Antiproton Collisions at square root s = 1.96 TeV  

SciTech Connect

We search for third generation vector leptoquarks (V LQ3) produced in colliding p{bar p} beams operating at {radical}s = 1.96 TeV at the CDF experiment in Run II of the Fermilab Tevatron. We use 322 pb{sup -1} of data to search for the V LQ3 signal in the di-tau plus di-jet channel. For the first time, the full matrix element is used in the Monte Carlo simulation of this signal. With no events observed in the signal region, we set a 95% C.L. upper limit on the V LQ3 pair production cross section of {sigma} < 344fb, assuming Yang-Mills couplings and Br(V LQ3 {yields} b{tau}) = 1, and a lower limit on the V LQ3 mass of m{sub V LQ3} > 317 GeV=c{sup 2}. If theoretical uncertainties on the cross section are applied in the least favorable manner the results are {sigma} < 360fb and m{sub V LQ3} > 294 GeV=c{sup 2}. The Minimal coupling V LQ3 result is an upper limit on the cross section of {sigma} < 493fb ({sigma} < 610fb) and the lower limit on the mass is m{sub V LQ3} > 251 GeV=c{sup 2} (m{sub V LQ3} > 223 GeV=c{sup 2}) for the nominal (1{sigma} varied) theoretical expectation.

Forrester, Stanley Scott; /UC, Davis

2006-12-01

167

Middle Proterozoic thrusting in central New Mexico  

SciTech Connect

Ductile thrust faults truncate contact-metamorphic aureoles surrounding two 1.4 Ga plutons in central New Mexico. The Priest quartz monzonite (1440 Ma) and Sandia granite (1420 Ma) are 50 km apart in the continuous Sandia/Manzano mountain chain. Thermobarometry and phase relations demonstrate that country-rock temperatures rose from 700 C toward the pluton, at pressure near 4 kb. The northern edge of this aureole is cut by the southeast-dipping ductile Monte Largo thrust fault. Prograde, greenschist-facies metamorphism of footwall rocks accompanied local retrogression of hangingwall rocks during thrusting. This second metamorphism took place at P-T conditions of 2-3 kb and 450-475 C. Another contact aureole surrounds the Sandia granite. Mafic rocks near the granite reflect amphibolite-facies conditions, whereas pelites display low-pressure contact assemblages. Quantitative temperatures increase from 500--750 C toward the granite, at pressures of 2.5--3.5 kb. The shallowly southeast-dipping Vincent Moore fault truncates the Sandia granite and the southern portion of its contact aureole. This ductile shear zone emplaced greenschist-facies rocks northwestward above the Sandia contact aureole. Footwall rocks were retrograded to the greenschist facies within 100 m of this fault; the retrograde phases are aligned parallel to the trace of the thrust. Metamorphic temperatures in hangingwall rocks (during thrusting ) were 400-475 C at pressures above 2.75 kb. Additional northwest-vergent ductile thrusts are found elsewhere in the mountain chain. This may represent the age of thrusting and of the related greenschist and the related greenschist-facies metamorphic overprint.

Grambling, J.A.; Thompson, A.G. (Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences); Dallmeyer, R.D. (Univ. of Georgia, Athens, GA (United States). Dept. of Geology)

1992-01-01

168

Supersonic jet noise - Its generation, prediction and effects on people and structures  

Microsoft Academic Search

This paper presents the results of a study aimed at quantifying the effects of jet source noise reduction, increases in aircraft lift, and reduced aircraft thrust on the take-off noise associated with supersonic civil transports. Supersonic jet noise sources are first described, and their frequency and directivity dependence are defined. The study utilizes NASA's Aircraft Noise Prediction Program in a

J. S. Preisser; R. A. Golub; J. M. Seiner; C. A. Powell

1990-01-01

169

A Experimental Study of the Velocity Field of a Transverse Jet Injected Into a Supersonic Crossflow.  

NASA Astrophysics Data System (ADS)

The design of a supersonic combustor which uses transverse jet injection into a supersonic flow (TJISF) as a means of fuel injection and mixing requires a fundamental understanding of these flows. Such knowledge may also serve studies of the thrust vector control of rocket nozzles, the cooling of nozzle walls, and jet reaction force prediction. The present investigation is a quantitative, experimental study of a single, sonic, underexpanded, transverse jet injected into a Mach 1.6 crossflow. The motivation for this research program is to improve the fundamental understanding of the fluid dynamic mechanisms and mixing processes in this flow. Schlieren/shadowgraph photography, surface flow visualization, and two-component, frequency pre-shifted laser Doppler velocimetry (LDV) data have been obtained. Four LDV optical arrangements have been used to measure all three mean velocity components, five of the six kinematic Reynolds stresses, and the turbulent kinetic energy. The LDV system is equipped with a computer-controlled traverse system and has been used to provide velocity measurements at over 4,000 locations throughout the TJISF flowfield. The study focuses on the transverse, midline plane and two crossflow planes. The majority of the measurements in these planes has been made in the high gradient regions of the jet plume. Measurements of the mean and turbulent velocity fields helped resolve important issues in the study of the TJISF flowfield. These issues include the size and orientation of the recirculation regions upstream and downstream of the jet (including the horseshoe vortex just upstream of the jet); the structure and strength of the bow shock, barrel shock, and Mach disk; the structure, strength, and development of the kidney-shaped, counter-rotating vortex pair; the growth of the annular shear layer between the jet plume and the crossflow; the growth of the boundary layer beneath the jet plume; the Reynolds stress fields of the flow; the production of turbulent kinetic energy; and the degree of anisotropy of the turbulent stresses in this flow. In addition, the present study provides validation data for analytical and numerical predictions of the TJISF flowfield.

Santiago, Juan Gabriel

170

Vorticity dynamics and thrust during VRS  

NASA Astrophysics Data System (ADS)

Under certain conditions of rapid descent of a rotorcraft, the vortices that usually trail below a rotor disk to form the helical vortex wake collapse into a ring-like structure around the plane of the disk, which is known as the vortex ring state (VRS). The formation and subsequent breakdown of the ring-like vortex is accompanied by large thrust excursions. In axial descent the thrust excursions are aperiodic, while in non-axial descent a periodicity on the order of several tens of rotor revolutions is observed. We discuss here experimental observations of the phase relation between the thrust cycle and vorticity distribution. The experiments were performed in a towing tank using a three-blade rotor. Rotor thrust was measured by strain gages and the vorticity fields using PIV. The flow structure as marked by vorticity distribution highlight the changes in the flow topology during the VRS cycles contrast the flow behavior at the leading and the trailing edges. The flow over the trailing edge exhibits large variations, whereas that over the leading edge is more tamed. Maxima of the VRS thrust oscillations correlate well with the maxima of enstrophy observed at the trailing edge of the rotor disk.

Savas, Omer; Green, Richard; Caradonna, Francis

2007-11-01

171

Advanced thrust chambers for miniaturized engines  

NASA Astrophysics Data System (ADS)

The general approach in previous Kinetic Kill Vehicle (KKV) thruster design consisted of separate lightweight and low-cost thrust chambers, injectors and valves. A series of programs including hot-fire testing and hover flight tests has led to the design of a new generation liquid bipropellant thruster with an integrated chamber/injector/valve thruster design. System analyses indicate the composite approach provides thermal management for thrust chambers and that an integral injector/valve contributes to a high thrust to weight ratio thruster. Past experience and development test results of an Advanced Composite material are described. Advanced Composite material selection, chamber fabrication and testing program are discussed. The thrust chambers were evaluated on the basis of oxidation resistance, durability, permeability through the chambers walls, strength and performance with excellent results in all areas. Excellent thrust chamber durability was demonstrated with no measurable erosion after extensive accumulated hot-fire time at high chamber pressure. Results to date indicate that the existing technology provides producible, highly durable chambers for KKV applications.

Pavlinsky, Joseph

1992-07-01

172

A computational investigation of impulsive and pulsed starting annular jets  

NASA Astrophysics Data System (ADS)

A computational study is carried out on low Reynolds number impulsive and pulsating annular jets. This work is inspired by the biological flow of marine life that uses jet propulsion for self maneuver. Marine life such as squids and jellyfish propel themselves by discharging a water jet followed by a refilling phase. The discharging portion is a starting jet, i.e. the releasing of a moving fluid into a quiescent fluid, while the refilling phase can be viewed as an inflow jet. The combined jets will be called fully oscillating jets. Although fully oscillating jets have been indirectly examined experimentally, they have never been studied computationally. This dissertation is divided into three investigations that examine the starting jet, inflow jet, and fully oscillating jet based on the resultant force (i.e. either thrust or suction force) at the annulus exit plane, jet efficiency, and vortex dynamics. Furthermore, each of the following three performance criterion is examined under various velocity imposed boundaries (i.e. impulsive, unit pulsed, and sinusoidal pulsed jets), ambient pressure, and blocking ratios. An axisymmetric, incompressible and unsteady Navier Stokes numerical model was used to implement the analysis. The model was validated against theoretical and experimental results, where both result types bounded the computational results of this endeavor. In addition, numerical verification was carried out on each of the three investigations ensuring grid and time independent results. Several substantial outcomes were drawn from the results of the three investigations. The numerical results confirmed previously published experimental data regarding the universal dimensionless time scale (i.e. vortex formation number) of optimal vortex ring development triggered by starting jets. Moreover, the computational results showed evidence that the vortex formation number was not affected by ambient pressure nor blocking ratio. The computational results also confirmed earlier experimental findings that pulsed jet inflows trigger a standing vortex ring. Furthermore, the current study showed that impulsive jet inflows do not trigger vortex ring formation. In addition, unlike the expected net thrust of zero due to mass flux, fully oscillating jets showed evidence of thrust augmentation due to the enhanced entrainment caused by the vortex formation.

Abdel-Raouf, Emad Mohamed Refaat

173

Pulsed thrust measurements using electromagnetic calibration techniques  

SciTech Connect

A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 {mu}N s using a noncontact electromagnetic calibration technique is described. In particular, a permanent magnet structure was designed to produce a uniform magnetic field, and a multiturn coil was made to produce a calibration force less than 10 mN. The electromagnetic calibration force for pulsed thrust measurements was linear to the coil current and changed less than 2.5% when the distance between the coil and magnet changed 6 mm. A pulsed plasma thruster was first tested on the thrust stand, and afterward five single impulse bits were measured to give a 310 {mu}N s average impulse bit. Uncertainty of the measured impulse bit was analyzed to evaluate the quality of the measurement and was found to be 10 {mu}N s with 95% credibility.

Tang Haibin; Shi Chenbo; Zhang Xin'ai; Zhang Zun; Cheng Jiao [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

2011-03-15

174

Astrophysical Jets  

ScienceCinema

Many astrophysical sources - especially those powered by release of gravitational energy - are associated with an outflow of material, generally taking place along the axis of symmetry of the system. In the most extreme cases, the outflow is accelerated to relativistic speeds; such a phenomenon is known as an astrophysical jet. When a relativistic jet points close to our line of sight, the observed radiation is strongly Doppler-boosted. Most spectacular cases of astrophysical jets are those produced by active galactic nuclei, where the measured spectrum - presumably dominated by the radiation from the jet - reaches up to the multi-GeV range. Our knowledge of these jets is limited: we don't fully understand how are they formed, collimated, and accelerated, and what is the process of conversion of the bulk energy of the jet into radiation. We anticipate that the increased sensitivity of GLAST will provide us with spectacular data yielding new insights as to their origin and structure.

175

Low thrust NTP for manned Mars operations  

SciTech Connect

The impact on manned Mars operations of selecting a nuclear thermal propulsion (NTP) module with a relatively low total thrust, in the 222--445 kN (50--100 klbf) range, is explored. The propulsion module may consist of one or more engines. Selection of a low total thrust is robust across a wide range of payload masses provided perigee kicks are utilized for trans-Mars insertion (TMI). The longer time taken for TMI when using a low total thrust and perigee kicks allows for extensive system evaluation before commitment to Earth escape, but will require fuels with lifetimes of at least a few hours. Longer fuel life could be obtained without using advanced fuels by operating at lower fuel temperatures later in the mission. The additional traversals through the Van Allen belts inherent with using perigee kicks for TMI does not significantly increase the radiation exposure of the crew. Negative reactivity from xenon buildup between perigee kicks can be mitigated by coasting on the intermediate orbits, by altering the selection of the intermediate orbits, by deep throttling, or by building in sufficient excess reactivity. Thrust misalignments of a realistic magnitude do not pose an Earth impact hazard. Engine crosstalk in clusters is a very manageable problem. High propulsion module reliability can be achieved with a propulsion module consisting of a cluster of three or four small engines without dropping the module thrust-to-weight ratio below an acceptable level. A total design thrust in the 222--445 kN range is high enough for Earth return with only one of the engines of the cluster operating.

Olsen, T.; Madsen, W. (Idaho National Engineering Laboratory, EG G Idaho, Inc., P.O. Box 1625, Idaho Falls, Idaho 83415-3413 (United States)); Redd, L. (Department of Energy, Office of Space, Idaho Field Office, 785 D.O.E. Place, Idaho Falls, Idaho 83402 (United States))

1993-01-10

176

Future Jet Technologies. Part B. F-35 Future Risks v. JS-Education of Pilots & Engineers  

NASA Astrophysics Data System (ADS)

Design of “Next-Generation” airframes based on supermarket-jet-engine-components is nowadays passé. A novel integration methodology [Gal-Or, “Editorial-Review, Part A”, 2011, Gal-Or, “Vectored Propulsion, Supermaneuverability and Robot Aircraft”, Springer Verlag, Gal-Or, Int'l. J. of Thermal and Fluid Sciences 7: 1-6, 1998, “Introduction”, 2011] is nowadays in. For advanced fighter aircraft it begins with JS-based powerplant, which takes up to three times longer to mature vis-à-vis the airframe, unless “committee's design” enforces a dormant catastrophe. Jet Steering (JS) or Thrust Vectoring Flight Control, is a classified, integrated engine-airframe technology aimed at maximizing post-stall-maneuverability, flight safety, efficiency and flight envelopes of manned and unmanned air vehicles, especially in the “impossible-to-fly”, post-stall flight domains where the 100+ years old, stall-spin-limited, Conventional Flight Control fails. Worldwide success in adopting the post-stall, JS-revolution, opens a new era in aviation, with unprecedented design variables identified here for a critical review of F-35 future risks v. future fleets of jet-steered, pilotless vehicles, like the X-47B/C. From the educational point of view, it is also instructive to comprehend the causes of long, intensive opposition to adopt post-stall, JS ideas. A review of such debates may also curb a future opposition to adopt more advanced, JS-based technologies, tests, strategies, tactics and missions within the evolving air, marine and land applications of JS. Most important, re-education of pilots and engineers requires adding post-stall, JS-based studies to curriculum & R&D.

Gal-Or, Benjamin

2011-09-01

177

Gravitomagnetic jets  

SciTech Connect

We present a family of dynamic rotating cylindrically symmetric Ricci-flat gravitational fields whose geodesic motions have the structure of gravitomagnetic jets. These correspond to helical motions of free test particles up and down parallel to the axis of cylindrical symmetry and are reminiscent of the motion of test charges in a magnetic field. The speed of a test particle in a gravitomagnetic jet asymptotically approaches the speed of light. Moreover, numerical evidence suggests that jets are attractors. The possible implications of our results for the role of gravitomagnetism in the formation of astrophysical jets are briefly discussed.

Chicone, C.; Mashhoon, B. [Department of Mathematics and Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211 (United States); Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211 (United States)

2011-03-15

178

Micro Jet Generation with Annular Plasma Actuators  

NASA Astrophysics Data System (ADS)

The effectiveness of dielectric barrier discharge plasma actuators for use in micro thrusters and internal duct aerodynamics are investigated. The primary flow is driven by tha zero-net mass flux jet at the wall in a closed circumferential arrangemen that then entrains fluid in the core of the duct. This results in a unique configuration for studying impulsively started jet phenomena. Laser flow visualization is utilized to observe detailed flow structure wherein multiple vortex rings are formed immediately after pulsed actuation and evolve into a turbulent jet downstream. Measurements are made using PIV and the effects of modulation frequency and the duty cycle on the induced velocity and resulting thrust are observed. The values of the induced velocities increase with the forcing frequency and duty cycle although there is a peak value for the forcing frequency after which the velocity and thrust decrease. The influence of the length-to-diameter (l/di) ratio is also significant; the velocities and thrust increase as the inner diameter of the tubes are increased. Velocity profiles show a great difference with this ratio. As the inner diameter is increased, a recirculation region at the center of the tube with negative velocities can be observed. The effect of freestream on the induced veloicty profiles is also studied wherein the duct is placed inside a wind tunnel and tests are conducted at different Re.

Ozturk, Ceren; Jacob, Jamey

2008-11-01

179

Discrete tone generation from free and confined high pressure ratio axisymmetric jets  

Microsoft Academic Search

The discrete tone generation from axisymmetric high-pressure ratio supersonic jets issuing from convergent and convergent-divergent nozzles was investigated for both free jets and jets confined in a cylindrical duct, on the basis of spectral analyses of emitted noise. The experimental measurements included those on the emitted noise, the confining duct-wall static pressure, and the duct axial thrust. It was found

Adnan M. Abdel-Fattah

1989-01-01

180

Research and Development of Lift-Jet Engine, 2.  

National Technical Information Service (NTIS)

The lift jet engine JR100V, scheduled to power a research plane during VTOL mode operations is reviewed. The JR100V was developed as a version of the JR100 series engines. It features higher thrust to weight ratio than that of the JR100F which was equippe...

1982-01-01

181

Thrust reverser for high bypass turbofan engine  

SciTech Connect

This patent describes a thrust reverser for a gas turbine engine of the type which includes an outer wall spaced from the center body of a core engine to define a bypass duct therebetween. The thrust reverser comprising: circumferentially displaced blocker doors, each of the doors being movable between a normal position generally aligned with the outer wall and a thrust reversing position extending transversely of the bypass duct for blocking the exhaust of air through the bypass duct and directing the air through an opening in the outer wall for thrust reversal; each of the blocker doors being of lightweight construction and including a pit in the inner surface thereof in the normal position; means for covering the pit during normal flow of air through the bypass duct to reduce the pressure drop in the bypass duct and to reduce noise. The covering means including a pit cover hingedly mounted at one end thereof on the blocker door and means of biasing the pit cover away from the blocker door to a position providing smooth flow of air through the bypass duct during normal operation.

Matta, R.K.; Bhutiani, P.K.

1990-05-08

182

Vorticity dynamics and thrust during VRS  

Microsoft Academic Search

Under certain conditions of rapid descent of a rotorcraft, the vortices that usually trail below a rotor disk to form the helical vortex wake collapse into a ring-like structure around the plane of the disk, which is known as the vortex ring state (VRS). The formation and subsequent breakdown of the ring-like vortex is accompanied by large thrust excursions. In

Omer Savas; Richard Green; Francis Caradonna

2007-01-01

183

Vortex Ring State and Asymmetric Thrust Oscillations  

Microsoft Academic Search

When the helical vortices of a rotor are not convected away, the vortices may form a ring-like structure about the rotor disk. This vortex ring state (VRS) is most common during rapid descent and leads to thrust oscillations coupled to the formation and subsequent breakdown of the ring. Experimental observations at and near VRS were made using strobed particle image

Gregory McCauley; Omer Savas; Francis Caradonna

2008-01-01

184

Dynamic Calibrator Pulse Thrust Test Module.  

National Technical Information Service (NTIS)

This report describes the development of a dynamic calibrator mechanism which is incorporated as an integral part of a pulse thrust test stand system utilizing an acceleration-compensated load cell. The complete system is called a Dynamic Calibrator/Pulse...

R. E. Nelson J. V. Hobbs R. W. Postma

1969-01-01

185

The resummed thrust distribution in DIS  

NASA Astrophysics Data System (ADS)

We present preliminary results on the resummation of leading and next-to-leading logarithms for the thrust distribution in deep inelastic scattering. Our predictions, expanded to ?s2), are compared with corresponding results from the Monte Carlo programs DISASTER++ and DISENT.

Antonelli, V.; Dasgupta, M.; Salam, G. P.

2000-05-01

186

Synthetic jets  

Microsoft Academic Search

The evolution of a synthetic (zero-net mass flux) jet and the flow mechanisms of its interaction with a cross flow are reviewed. An isolated synthetic jet is produced by the interactions of a train of vortices that are typically formed by alternating momentary ejection and suction of fluid across an orifice such that the net mass flux is zero. A

Ari Glezer; Michael Amitay

2002-01-01

187

Volcanic jet noise: infrasonic source processes and atmospheric propagation  

NASA Astrophysics Data System (ADS)

Volcanic eruption columns are complex flows consisting of (possibly supersonic) injections of ash-gas mixtures into the atmosphere. A volcanic eruption column can be modeled as a lower momentum-driven jet (the gas-thrust region), which transitions with altitude into a thermally buoyant plume. Matoza et al. [2009] proposed that broadband infrasonic signals recorded during this type of volcanic activity represent a low-frequency form of jet noise. Jet noise is produced at higher acoustic frequencies by smaller-scale man-made jet flows (e.g., turbulent jet flow from jet engines and rockets). Jet noise generation processes could operate at larger spatial scales and produce infrasonic frequencies in the lower gas-thrust portion of the eruption column. Jet-noise-like infrasonic signals have been observed at ranges of tens to thousands of kilometers from sustained volcanic explosions at Mount St. Helens, WA; Tungurahua, Ecuador; Redoubt, AK; and Sarychev Peak, Kuril Islands. Over such distances, the atmosphere cannot be considered homogeneous. Long-range infrasound propagation takes place primarily in waveguides formed by vertical gradients in temperature and horizontal winds, and exhibits strong spatiotemporal variability. The timing and location of volcanic explosions can be estimated from remote infrasonic data and could be used with ash cloud dispersion forecasts for hazard mitigation. Source studies of infrasonic volcanic jet noise, coupled with infrasound propagation modeling, hold promise for being able to constrain more detailed eruption jet parameters with remote, ground-based geophysical data. Here we present recent work on the generation and propagation of volcanic jet noise. Matoza, R. S., D. Fee, M. A. Garcés, J. M. Seiner, P. A. Ramón, and M. A. H. Hedlin (2009), Infrasonic jet noise from volcanic eruptions, Geophys. Res. Lett., 36, L08303, doi:10.1029/2008GL036486.

Matoza, R. S.; Fee, D.; Ogden, D. E.

2011-12-01

188

Structural Analysis of Cylindrical Thrust Chambers, Volume 1.  

National Technical Information Service (NTIS)

Life predictions of regeneratively cooled rocket thrust chambers are normally derived from classical material fatigue principles. The failures observed in experimental thrust chambers do not appear to be due entirely to material fatigue. The chamber coola...

W. H. Armstrong

1979-01-01

189

14 CFR 33.79 - Fuel burning thrust augmentor.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.79 Fuel burning thrust augmentor. Each fuel burning thrust augmentor, including the...

2013-01-01

190

14 CFR 25.945 - Thrust or power augmentation system.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Thrust or power augmentation system. 25.945 Section 25...General § 25.945 Thrust or power augmentation system. (a) General. ...performance. (b) Fluid tanks. Each augmentation system fluid tank must meet the...

2009-01-01

191

14 CFR 25.945 - Thrust or power augmentation system.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Thrust or power augmentation system. 25.945 Section 25...General § 25.945 Thrust or power augmentation system. (a) General. ...performance. (b) Fluid tanks. Each augmentation system fluid tank must meet the...

2010-01-01

192

High-power, null-type, inverted pendulum thrust stand  

Microsoft Academic Search

This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error

Kunning G. Xu; Mitchell L. R. Walker

2009-01-01

193

High-power, null-type, inverted pendulum thrust stand  

Microsoft Academic Search

This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error

Kunning G. Xu; Mitchell L. R. Walker

194

Development of the Himalayan frontal thrust zone: Salt Range, Pakistan  

Microsoft Academic Search

The Salt Range is the active frontal thrust zone of the Himalaya in Pakistan. Seismic reflection data show that a 1 km offset of the basement acted as a buttress that caused the central Salt Range-Potwar Plateau thrust sheet to ramp to the surface, exposing Mesozoic and Paleozoic strata. The frontal part of the thrust sheet was folded passively as

Dan M. Baker; Robert J. Lillie; Robert S. Yeats; Gary D. Johnson; Mohammad Yousuf; Agha Sher Hamid Zamin

1988-01-01

195

Direct thrust controlled linear induction motor including end effect  

Microsoft Academic Search

As a special feature, the linear induction motor (LIM) has an end effect phenomena causing weakening in airgap flux also in thrust. In this paper, direct thrust control of linear induction motors is improved by considering the end effect in flux and thrust estimator part based on the mathematical model of LIM. To show the effectiveness of the improved system,

Berrin Susluoglu; Vedat M. Karsli

2008-01-01

196

Reconstruction of Hydroturbine Units with Transition to Stiff Thrust Bearing  

Microsoft Academic Search

Prevailing use of hydraulic thrust bearings in vertical high- and medium-power hydroturbine units for over 30 years has virtually eliminated the experience of mounting, adjusting, and servicing of thrust bearings on a stiff screw support. The author will make an attempt to fill the gap using data obtained in replacement of hydraulic thrust bearing of one of the hydroturbine units

A. I. Popov

2005-01-01

197

Kinematical bounds on jet variables and the heavy jet mass distribution  

NASA Astrophysics Data System (ADS)

We investigate the dependence of the bounds of several QCD jet variables on the order of perturbation theory. We show that the ratio of the heavy jet invariant mass squared to the c.m. energy, MH2/s, is bounded by 1/3 in every order of perturbation theory. To illustrate the consequences, using the recent gluon loop calculations of Ellis et al. we calculate d?/d(MH2/s) to order ?s2 and contrast it with the thrust distribution. It is suggested that the perturbation series for MH2/s converges faster and agrees better with experiment away from the infrared sensitive region.

Clavelli, L.; Wyler, D.

1981-07-01

198

Composite Octet Searches with Jet Substructure  

SciTech Connect

Many new physics models with strongly interacting sectors predict a mass hierarchy between the lightest vector meson and the lightest pseudoscalar mesons. We examine the power of jet substructure tools to extend the 7 TeV LHC sensitivity to these new states for the case of QCD octet mesons, considering both two gluon and two b-jet decay modes for the pseudoscalar mesons. We develop both a simple dijet search using only the jet mass and a more sophisticated jet substructure analysis, both of which can discover the composite octets in a dijet-like signature. The reach depends on the mass hierarchy between the vector and pseudoscalar mesons. We find that for the pseudoscalar-to-vector meson mass ratio below approximately 0.2 the simple jet mass analysis provides the best discovery limit; for a ratio between 0.2 and the QCD-like value of 0.3, the sophisticated jet substructure analysis has the best discovery potential; for a ratio above approximately 0.3, the standard four-jet analysis is more suitable.

Bai, Yang; /SLAC; Shelton, Jessie; /Yale U.

2012-02-14

199

On using multiple-jet nozzles to suppress industrial jet noise.  

PubMed

This work investigates the efficacy of multiple-jet nozzles in reducing exposure to noise radiated from high-speed jet flows that are frequently used for cleaning and other purposes. A single-jet nozzle is replaced by one with multiple and smaller outlets with the same combined exit area. Noise generated by multiple-jet nozzles will shift to higher frequencies due to the smaller openings; thus, a portion of the sound energy is moved to the ultrasonic range and the audible noise levels will be reduced. In this study, nozzle outlet sizes of 2.2 mm, 2 mm, 1 mm, and 0.7 mm are tested at various flow rates. Results show that the noise-abating effect of using smaller outlets is significant. Although industrial jet flows, in general, have multiple noise-generating mechanisms, the multiple-jet approach is effective for flows ranging from the subsonic to the highly choked. Noise spectra show that the reduction of noise level in the audible range is related to frequency shifting. The comparison of overall sound pressure levels generated by 1-mm and 0.7-mm outlets shows that even a raise of frequency by 40% can have a notable effect. As for the concern that the multiple-jet nozzles may suffer a drop in thrust, as long as the total exit area is fixed, thrust loss generally is not serious. One potential hazard of the multiple-jet nozzle is that posed by noise at frequencies higher than 10 kHz or ultrasound. More investigations in this field are suggested. PMID:17620188

Sheen, Shaw-Ching; Hsiao, Yi-Han

2007-09-01

200

Vector Addition  

NSDL National Science Digital Library

This 2D applet simulates vector addition geometrically. The user selects the angle and magnitude of two vectors, which are then added together by the applet. The resultant vector and the values of its magnitude and angle, as well as the values of the x and y components of all three vectors, are calculated and displayed.

Duffy, Andrew

2004-11-28

201

Vector Calculator  

NSDL National Science Digital Library

A simple Java applet enabling users to add two two-dimensional vectors. The user can choose the two vectors by clicking on a grid. The components, magnitude, and direction are immediately shown. Once the two vectors are chosen, a press of a button shows the vector sum, its components, its magnitude and its direction.

Gea-Banacloche

2009-08-10

202

Design, calibration and error analysis of a piezoelectric thrust dynamometer for small thrust liquid pulsed rocket engines  

Microsoft Academic Search

Small thrust liquid pulsed rocket engines operating in pulsed mode have gained a good reputation in attitude control applications for their potential reliability and efficiency. However, the pulsed characteristic creates a difficult measurement problem. In this paper, a novel thrust dynamometer with high natural frequency is developed for accurately measuring the pulsed thrust. It consists of two shear mode piezoelectric

Qin Xing; Jun Zhang; Min Qian; Zhenyuan Jia; Baoyuan Sun

2011-01-01

203

Structural geology and regional tectonic significance of the Ramgarh thrust, Himalayan fold-thrust belt of Nepal  

Microsoft Academic Search

The Ramgarh thrust is one of the major fault systems of the Himalayan thrust belt in Nepal and northern India. The Ramgarh thrust sheet is ?0.2–2.0 km thick and can be traced along strike the entire length of the Himalaya in Nepal. The fault generally places the oldest Paleoproterozoic rocks in the Lesser Himalayan series upon younger Lesser Himalayan rocks

Ofori N. Pearson; Peter G. DeCelles

2005-01-01

204

Thrust production by a mechanical swimming lamprey  

NASA Astrophysics Data System (ADS)

To develop a comprehensive model of lamprey locomotion, we use a robotic lamprey to investigate the formation of the wake structure, the shedding vorticity from the body, and the relationship between thrust production and pressure on the surface of the robot. The robot mimics the motion of living lamprey in steady swimming by using a programmable microcomputer to actuate 13 servomotors that produce a traveling wave along the length of the lamprey body. The amplitude of the phase-averaged surface pressure distribution along the centerline of the robot increases toward the tail, which is consistent with previous momentum balance experiments. This indicates that thrust is produced mainly at the tail. The phase relationship between the pressure signal and the vortex shedding from the tail is also examined, showing a clear connection between the location of vortex structures and the fluctuations of the pressure signal.

Leftwich, M. C.; Smits, A. J.

2011-05-01

205

NATURAL BARRIERS TARGETED THRUST FY 2004 PROJECTS  

SciTech Connect

This booklet contains project descriptions of work performed by the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology and International's (OST&I) Natural Barriers Targeted Thrust during Fiscal Year (FY) 2004. The Natural Barriers Targeted Thrust is part of OST&I's Science and Technology Program which supports the OCRWM mission to manage and dispose of high-level radioactive waste and spent nuclear fuel in a manner that protects health, safety, and the environment; enhances national and energy security; and merits public confidence. In general, the projects described will continue beyond FY 2004 assuming that the technical work remains relevant to the proposed Yucca Mountain Repository and sufficient funding is made available to the Science and Technology Program.

NA

2005-07-27

206

Twin Jet.  

National Technical Information Service (NTIS)

Many subsonic and supersonic vehicles in the current fleet have multiple engines mounted near one another. Some future vehicle concepts may use innovative propulsion systems such as distributed propulsion which will result in multiple jets mounted in clos...

B. Henderson R. Bozak

2010-01-01

207

Low-thrust control of orbital elements  

NASA Astrophysics Data System (ADS)

This dissertation presents a method for controlling the orbital elements of a spacecraft using continuous low-thrust systems. The method involves the use of a general performance index, which is designed to minimize the difference between the instantaneous orbital elements of a spacecraft and some desired set of orbital elements. Due to the generality of the controller design, the resultant controller can be applied to a wide variety of scenarios about various bodies in space. To minimize the designed performance index, a shooting method and a Sequential Quadratic Programming algorithm are utilized and compared. The primary application of the general controller design in this study is the problem of generating and maintaining low-altitude, polar, Sun-synchronous orbits about the Moon. Such orbits are useful for lunar mapping missions, such as with NASA's Lunar Reconnaissance Orbiter (LRO) mission which began in June of 2009. While Sun-synchronous orbits are known to exist naturally about Earth, lunar Sun-synchronous orbits do not exist naturally and instead require a set of continuous low-thrust control actions for stationkeeping. In this dissertation, it is shown that Sun-synchronous orbits can be maintained for extended periods of time using low out-of-plane thrust levels. The steering profiles necessary for stationkeeping these orbits are shown to follow simple periodic profiles. From a literature search, this is the first known work which has studied the techniques required for maintaining Sun-synchronous orbits about the Moon. In order to demonstrate the effectiveness of the general controller design, it is also applied to two additional astronautical problems of interest. In particular, the controller design is applied to the problem of an orbit transfer between two inclined geosynchronous orbits about Earth and the problem of low-thrust asteroid deflection.

Harl, Nathan Robert

208

Discrete tone generation from free and confined high pressure ratio axisymmetric jets  

NASA Astrophysics Data System (ADS)

The discrete tone generation from axisymmetric high-pressure ratio supersonic jets issuing from convergent and convergent-divergent nozzles was investigated for both free jets and jets confined in a cylindrical duct, on the basis of spectral analyses of emitted noise. The experimental measurements included those on the emitted noise, the confining duct-wall static pressure, and the duct axial thrust. It was found that the pressure ratio at which frequency changes occurred varied with the nozzle expansion ratio and coincided with irregularities in the measured duct axial thrust and the bell-mouth static pressure characteristics. The overall sound pressure levels and discrete tone amplitudes for the confined jet were found to be always higher than those corresponding to the free jet.

Abdel-Fattah, Adnan M.

209

The thrust belts of Western North America  

SciTech Connect

Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

Moulton, F.C.

1993-08-01

210

Thrust Increase of Air Breathing Pulse Detonation Engine by High Supply Pressure  

NASA Astrophysics Data System (ADS)

For an application of PDE to hypersonic air-breathing engines, thrust performances of air-breathing PDEs are estimated analytically in this study. Thrust/weight ratio of the engine decreases with increasing flight speed because of a low density of atmospheric air. In order to improve this disadvantage, new concept air-breathing PDE is proposed. By closing the exit of the PDE combustion chamber during a filling phase, ram pressure of the intake can be utilized effectively. Furthermore, by cooling the intake exit air by the cryogenic fuel, flight range can be extended for M 0.5. After system analysis of the air-breathing PDE, PDRJE (Pulse Detonation Ram Jet Engine) with air precooler is proposed. Size of PDRJE is 0.3 m in cowl inlet diameter. Engine thrust and weight are estimated to be 4.6x103 N and 74 kg respectively. To evaluate the basic performances of the PDE, firing test of the scaled model was performed using GH2 and GOX. Heat flux of the combustion chamber was approximately 5 kW/m2/Hz.

Kojima, Takayuki; Kobayashi, Hiroaki

211

Jet measurements at D0 using a KT algorithm  

SciTech Connect

D0 has implemented and calibrated a k{perpendicular} jet algorithm for the first time in a p{bar p} collider. We present two results based on 1992-1996 data which were recently published: the subjet multiplicity in quark and gluon jets and the central inclusive jet cross section. The measured ratio between subjet multiplicities in gluon and quark jets is consistent with theoretical predictions and previous experimental values. NLO pQCD predictions of the k{perpendicular} inclusive jet cross section agree with the D0 measurement, although marginally in the low p{sub T} range. We also present a preliminary measurement of thrust cross sections, which indicates the need to include higher than {alpha}{sub s}{sup 3} terms and resumation in the theoretical calculations.

V.Daniel Elvira

2002-10-03

212

Jet-diffuser ejector - Attached nozzle design  

NASA Astrophysics Data System (ADS)

Attached primary nozzles were developed to replace the detached nozzles of jet-diffuser ejectors. Slotted primary nozzles located at the inlet lip and injecting fluid normal to the thrust axis, and rotating the fluid into the thrust direction using the Coanda Effect were investigated. Experiments indicated excessive skin friction or momentum cancellation due to impingement of opposing jets resulted in performance degradation. This indicated a desirability for location and orientation of the injection point at positions removed from the immediate vicinity of the inlet surface, and at an acute angle with respect to the thrust axis. Various nozzle designs were tested over a range of positions and orientations. The problems of aircraft integration of the ejector, and internal and external nozzle losses were also considered and a geometry for the attached nozzles was selected. The effect of leaks, protrusions, and asymmetries in the ejector surfaces was examined. The results indicated a relative insensitivity to all surface irregularities, except for large protrusions at the throat of the ejector.

Alperin, M.; Wu, J. J.

1980-05-01

213

Vector Voyage!  

NSDL National Science Digital Library

In this activity, students will use vector analysis to understand the concept of dead reckoning. Students will use vectors to plot their course based on a time and speed. They will then correct the positions with vectors representing winds and currents.

Integrated Teaching And Learning Program

214

K (transverse) jet algorithms in hadron colliders: The D0 experience  

SciTech Connect

D0 has implemented and studied a k{sub {perpendicular}} jet algorithm for the first time in a hadron collider. The authors have submitted two physics results for publication: the subjet multiplicity in quark and gluon jets and the central inclusive jet cross section measurements. A third result, a measurement of thrust distributions in jet events, is underway. A combination of measurements using several types of algorithms and samples taken at different center-of-mass energies is desirable to understand and distinguish with higher accuracy between instrumentation and physics effects.

V. Daniel Elvira

2002-12-05

215

$W/Z$ + jets results from CDF  

SciTech Connect

The CDF Collaboration has a comprehensive program of studying the production of vector bosons, W and Z, in association with energetic jets. Excellent understanding of the standard model W/Z+jets and W/Z+c,b-jets processes is of paramount importance for the top quark physics and for the Higgs boson and many new physics searches. We review the latest CDF results on Z-boson production in association with inclusive and b-quark jets, study of the p{sub T} balance in Z+jet events, and a measurement of the W+charm production cross section. The results are based on 4-5 fb{sup -1} of data and compared to various Monte Carlo and next-to-leading order perturbative QCD predictions.

Camarda, Stefano; /Barcelona, IFAE

2010-01-01

216

Reattachment of a three-dimensional, incompressible jet to an adjacent axisymmetric inclined surface  

NASA Astrophysics Data System (ADS)

A study was made of the fluid mechanics of a thrust reverser jet reattaching to an aircraft nozzle afterbody. The problem basically involves the Coanda effect flow of a three dimensional, incompressible jet to an adjacent axisymmetric, inclined surface. The equations were derived in integral form and programmed for numerical solution for the case of an exhaust flow with no opposing free stream flow. Test data are reported for a scale model of a nozzle afterbody exhausting against a target-type thrust reverser. Data are presented for surface pressure coefficient at various points along the model.

Niemi, E. E., Jr.

1983-03-01

217

Fluid Flow and Deformation Along the Glarus Thrust, Eastern Switzerland  

NASA Astrophysics Data System (ADS)

The Glarus thrust is a prominent tectonic feature in the eastern Helvetic Alps. It accommodated an at least 40 kilometre northward displacement of the Helfvetic nappe system in the hangingwall of the thrust with respect to the Infrahelvetic units in the footwall. The Glarus thrust was active at sub-greenschist to greenschist facies conditions during Miozene times. Oxygen, carbon and strontium isotope patterns as well as bulk rock chemical compositions give evidence of both flow along and across the thrust. The oxygen isotope compositions of the Lochseite calc mylonite, a metre thick mylonite layer at the thrust contact, are generally low (about 12 per mil relative to V-SMOW) in the south and relatively high (about 21 per mill) in the north. This may be interpreted as an isotopic front that resulted from the northwards migration of isotopically light fluid along the thrust. This fluid was most likely derived from dehydration reactions associated with progressive metamorphism in the root zone some 20 kilometres south of the southernmost present day outcrops of the thrust. Data from sampling profiles across the thrust indicate that cross thrust fluid flow also contributed to this regional pattern. In the southern section of the thrust, where the footwall is represented by Mesozoic limestone, a downwards directed sub-vertical transport component is identified. In contrast, cross thrust flow was upwards directed in the northern section, where the footwall is represented by Tertiary flysch, from which water was expelled during thrusting. In the north, relatively high fluid pressures caused by ponding of the ascending fluids at the thrust contact favoured fracturing and strain localisation in the Lochseiten calc mylonite and in the lowermost one to two meters of the Verrucano in the hangingwall of the thrust. In the south this fluid pressure effect is missing. Nevertheless there is evidence for fracturing, but thrust related deformation migrated up into the hangingwall over several tens of meters. Microstructures and textures indicate that, apart from fracturing, pressure solution and limited crystal plasticity were active probably intermittently during deformation. The different fluid flow regimes in the northern and southern parts of the thrust appear to have had a major influence on the degree of strain localisation. Strain localisation was pronounced in the northern section, where the thrust was lubricated by fluids that ascended from the flysch in the footwall, and it was less pronounced in the southern section, where fluid supply from the footwall was missing.

Abart, R.; Badertscher, N.; Burkhard, M.

2002-12-01

218

Spaced button thrust surface for earth boring bit  

SciTech Connect

An earth boring bit has thrust surfaces with enhanced cooling features. The bit has a body with three depending bearing pins. A cutter having an axial cavity is mounted on each bearing pin. The bearing pin and the cavity have one or more mating thrust surfaces that are perpendicular to the axis of the bearing pin. These thrust surfaces absorb outward forces that the cutter imposes on the bearing pin. At least one of the thrust surfaces consists of a series of tungsten carbide buttons spaced in a circular array. These buttons have flat ends for engaging the opposite thrust surfaces. The buttons protrude from the supporting metal, allowing cooling fluid to be circulated past to cool the thrust surfaces.

Shepherd, W.L.

1984-05-29

219

A double pendulum plasma thrust balance and thrust measurement at a tandem mirror exhaust  

Microsoft Academic Search

For the purpose of measuring the plasma momentum flux in a plasma system, a highly sensitive and precision balance has been developed. It can measure a force, an impulse, or thrust as low as 0.1 mN free of mechanical noise, electrical and magnetic pickups. The double pendulum system consists of two parallel conducting plates. One or both of the plates

T. F. Yang; Ping Liu; F. R. Chang-Díaz; Harvey Lander; R. A. Childs; H. D. Becker; S. A. Fairfax

1995-01-01

220

Nanonewton thrust measurement of photon pressure propulsion using semiconductor laser  

Microsoft Academic Search

To evaluate the thrust produced by photon pressure emitted from a 100 W class continuous-wave semiconductor laser, a torsion-balance precise thrust stand is designed and tested. Photon emission propulsion using semiconductor light sources attract interests as a possible candidate for deep-space propellant-less propulsion and attitude control system. However, the thrust produced by photon emission as large as several ten nanonewtons

K. Iwami; Taku Akazawa; Tomohiro Ohtsuka; Hiroyuki Nishida; Norihiro Umeda

2011-01-01

221

Defining the Himalayan Main Central Thrust in Nepal  

Microsoft Academic Search

An inverted metamorphic field gradient associated with a crustal-scale south-vergent thrust fault, the Main Central Thrust, has been recognized along the Himalaya for over 100 years. A major problem in Himalayan structural geology is that recent workers have mapped the Main Central Thrust within the Greater Himalayan Sequence high-grade metamorphic sequence along several different structural levels. Some workers map the

MICHAEL P. S EARLE; D. L AW; L AURENT G ODIN; K YLE P. L ARSON; M. C OT; J. J ESSUP

2008-01-01

222

Moment\\/thrust interaction diagrams for reinforced masonry sections  

Microsoft Academic Search

This paper presents a numerical analysis for estimating moment\\/thrust interaction diagrams for reinforced masonry sections. Realistic constitutive models are used for the masonry and steel reinforcement. Considering compatibility of strains and equilibrium of forces on reinforced masonry sections, the moment–curvature relationships for different axial thrusts are first produced. The moment–thrust interaction diagrams are then developed. Comparisons between the behaviour predicted

Y. Chen; A. F. Ashour; S. W. Garrity

2008-01-01

223

Ramp initiation and spacing in a homogeneous thrust wedge  

Microsoft Academic Search

Fold-and-thrust belts grow largely through sequential initiation of thrust faults and subsequent motion on them from hinterland to foreland, i.e., away from the plate boundary. While perturbations in basal geometry, stratigraphy, excess fluid pressure, folding, and surface slope have all been suggested as mechanisms for thrust ramp nucleation, we show that preexisting inhomogeneities are not necessary. We present a mechanically

John Panian; David Wiltschko

2007-01-01

224

Vacuum Thrust Optimised Expansion Deflection Nozzles  

Microsoft Academic Search

ED nozzles have long been considered for launch vehicle applications, due to their postulated twin benefits of reduced length and altitude compensating capability. However, the difficulties involved in modelling the inviscid\\/viscous jet boundaries and associated flow phenomena during wake closure, have prevented the creation of a reliable method for the prediction of the performance characteristics of the type through atmospheric

N. V. Taylor; C. M. Hempsell

2002-01-01

225

Cretaceous biostratigraphy in the Wyoming thrust belt  

SciTech Connect

Biostratigraphy is essential to exploration for oil and gas in the Wyoming thrust belt because fossils provide a temporal framework for interpretation of events of faulting, erosion, sedimentation, and the development of hydrocarbon traps and migration pathways. In the Cretaceous section, fossils are especially useful for dating and correlating repetitive facies of different ages in structurally complex terrain. The biostratigraphic zonation for the region is based on megafossils (chiefly ammonites), which permit accurate dating and correlation of outcrop sections, and which have been calibrated with the radiometric time scale for the Western Interior. Molluscan and vertebrate zone fossils are difficult to obtain from the subsurface, however, and ammonities are restricted to rocks of margin origin. Palynomorphs (plant microfossils) have proven to be the most valuable fossils in investigations of stratigraphy and structures in the subsurface of the thrust belt because palynomorphs can be recovered from drill cuttings. Palynomorphs also are found in both marine and nonmarine rocks and can be used for correlation between facies. In this paper, stratigraphic ranges of selected Cretaceous marine and nonmarine palynomorphs in previously designated reference sections in Fossil Basin, Wyoming, are correlated with the occurrence of ammonities and other zone fossils in the same sections. These correlations can be related to known isotopic ages, and they contribute to the calibration of palynomorph ranges in the Cretaceous of the Western Interior.

Nichols, D.J. (U.S. Geological Survey, Denver, CO); Jacobson, S.R.

1982-07-01

226

Plasma flow deflection systems created for space electric jet thrusters  

NASA Astrophysics Data System (ADS)

In this paper a long-term deflection system for the accelerator plasma flux control is considered. Such systems utilization will permit varying the thrust vector angle over a wide range under low energy expenditure (5-10 W/grade). As one of alternatives a focusing and defocusing system of the compensated ion flux was studied.

Avakimian, B. O.; Kolesnikov, A. V.

1992-08-01

227

Gas Jets.  

National Technical Information Service (NTIS)

A brief summary of the contents of this paper is presented here. In part I the differential equations of the problem of a gas flow in two dimensions is derived and the particular integrals by which the problem on jets is solved are given. Use is made of t...

S. Chaplygin

2003-01-01

228

Nanonewton thrust measurement of photon pressure propulsion using semiconductor laser  

NASA Astrophysics Data System (ADS)

To evaluate the thrust produced by photon pressure emitted from a 100 W class continuous-wave semiconductor laser, a torsion-balance precise thrust stand is designed and tested. Photon emission propulsion using semiconductor light sources attract interests as a possible candidate for deep-space propellant-less propulsion and attitude control system. However, the thrust produced by photon emission as large as several ten nanonewtons requires precise thrust stand. A resonant method is adopted to enhance the sensitivity of the biflier torsional-spring thrust stand. The torsional spring constant and the resonant of the stand is 1.245 × 10-3 Nm/rad and 0.118 Hz, respectively. The experimental results showed good agreement with the theoretical estimation. The thrust efficiency for photon propulsion was also defined. A maximum thrust of 499 nN was produced by the laser with 208 W input power (75 W of optical output) corresponding to a thrust efficiency of 36.7%. The minimum detectable thrust of the stand was estimated to be 2.62 nN under oscillation at a frequency close to resonance.

Iwami, K.; Akazawa, Taku; Ohtsuka, Tomohiro; Nishida, Hiroyuki; Umeda, Norihiro

2011-09-01

229

[Lifting-thrusting and rotating manipulations: a comparison on energy input].  

PubMed

Through the energy input model of lifting-thrusting and rotating manipulations, using the theory of energy density, energy flux density and sound intensity level in physics, the average energy flux intensity and frequency distributions of average poynting's vector were calculated respectively within the range of infrasound. According to the distribution table, it was discovered that both of the energy flux density and sound intensity level during the process of acupuncture were high. And it was concluded that the essence of meridians was probably fascial tissues which were rich in elastic fibers and collagenous fibers. The heat-producing needling with reinforcing effect (setting the moutain on fire) which focused on forceful thrusting was held to be the result of the action of same position solitary wave. And the coolness-producing needling with reducing effect (thorough heavenly cool) emphasized on the manipulation of forceful lifting was considered as the action of opposite position solitary wave. The energy input of lifting-thrusting manipulation is comparatively larger than the rotating method, however without significant difference. The speed of manipulations applied is regarded to have greater impact on energy transmission. And the energy produced by rotating manipulation can be better transmitted through meridians. PMID:21355164

Wang, Xi-ming

2011-01-01

230

In-line motion causes high thrust and efficiency in flapping foils that use power downstroke.  

PubMed

We show experimentally that flapping foil kinematics consisting of a power downstroke and a feathering upstroke together with a properly timed in-line motion, similar to those employed in forelimb propulsion of sea turtles, can produce high thrust and be hydrodynamically as efficient as symmetrically flapping foils. The crucial parameter for such asymmetrically flapping foils is a properly sized and timed in-line motion, whose effect is quantified by a new parameter, the advance angle, defined as the angle of the foil trajectory with respect to the horizontal, evaluated at the middle of the power downstroke. We show, in particular, that optimal efficiency in high aspect ratio rigid foils, accompanied by significant thrust production, is obtained for Strouhal numbers in the range 0.2-0.6 for Reynolds number equal to 13,000, and for values of the advance angle around 0.55pi (100 deg.). The optimized kinematics consist of the foil moving back axially during the downstroke, in the direction of the oncoming flow, and rotating with a large pitch angle. This causes the force vector to rotate and become nearly parallel to the steady flow, thus providing a large thrust and a smaller transverse force. During the upstroke, the foil is feathering while it moves axially forward, i.e. away from the vorticity shed during the power stroke; as a result, the transverse force remains relatively small and no large drag force is produced. Observations from turtles confirm qualitatively the findings from the foil experiments. PMID:20008363

Licht, S C; Wibawa, M S; Hover, F S; Triantafyllou, M S

2010-01-01

231

Onset of the Somali Jet in the Arabian Sea during June 1997  

Microsoft Academic Search

The National Aeronautics and Space Administration scatterometer surface wind vectors are used to describe the rapid onset of the Somali Jet throughout the Arabian Sea. In June 1997 the time of Somali Jet onset varied over the Arabian Sea, with June 17-18 the average time. The Somali Jet appeared first in the western Arabian Sea, expanded over 2 weeks to

David Halpern; Peter M. Woiceshyn

1999-01-01

232

Erosional history and possible passive uplift of Paris-Willard Thrust allochthon, Wyoming-Idaho-Utah Thrust Belt  

Microsoft Academic Search

Stratigraphic distribution of clast lithologies in Sevier foreland basin synorogenic conglomerates in the southwestern Wyoming-southeastern Idaho-northeastern Utah thrust belt provides evidence of the erosional history of the Paris-Willard thrust allochthon. Conglomerates of the Upper Jurassic-Lower Cretaceous Gannett Group were deposited in response to initial movement along the Paris-Willard thrust system and are comprised of cobbles and pebbles of Ordovician through

James G. Schmitt

1985-01-01

233

Erosional history and possible passive uplift of Paris-Willard Thrust allochthon, Wyoming-Idaho-Utah Thrust Belt  

SciTech Connect

Stratigraphic distribution of clast lithologies in Sevier foreland basin synorogenic conglomerates in the southwestern Wyoming-southeastern Idaho-northeastern Utah thrust belt provides evidence of the erosional history of the Paris-Willard thrust allochthon. Conglomerates of the Upper Jurassic-Lower Cretaceous Gannett Group were deposited in response to initial movement along the Paris-Willard thrust system and are comprised of cobbles and pebbles of Ordovician through Jurassic strata, with upper Paleozoic and lower Mesozoic clasts most common. Thus, by conclusion of initial Paris-Willard thrust movement, the allochthon had been affected by widespread erosion of lower Paleozoic through lower Mesozoic strata. Evidence for subsequent erosion to deeper stratigraphic levels is contained in the basal Hams Fork Conglomerate Member of the Upper Cretaceous-Paleocene Evanston Formation. This unit contains abundant Precambrian quartzite cobbles, which must have been derived from the Paris-Willard allochthon, the only thrust sheet that contains Precambrian quartzite units. Genesis of the Hams Fork Conglomerate has been related to latest Cretaceous major movement along the Absaroka thrust. Thus, either the Paris-Willard thrust was fortuitously reactivated at the same time as major Absaroka thrust movement or uplift associated with movement along the Absaroka thrust resulted in coeval uplift of the Paris-Willard allochthon.

Schmitt, J.G.

1985-05-01

234

Thrust Production in a Mechanical Swimming Lamprey  

NASA Astrophysics Data System (ADS)

To develop a comprehensive model of lamprey locomotion, we use a robotic lamprey as a means of investigating the surface pressure and wake structure during swimming. A programmable microcomputer actuates 11 servomotors that produce a traveling wave along the length of the lamprey body. The waveform is based on the motion of the American eel (Anguilla rostrata), as described by Tytell and Lauder (2004) and kinematic studies of living lamprey. The amplitude of the phase-averaged surface pressure distribution along the centerline of the robot increases toward the tail, which is consistent with previous momentum balance experiments indicating that thrust is produced mainly at the tail. The phase relationship between the pressure signal and the vortex shedding from the tail is also examined. The project is supported by NIH CNRS Grant 1R01NS054271.

Leftwich, Megan; Smits, Alexander

2008-11-01

235

Matter content in AGN jets: constraint from cocoon dynamics?  

NASA Astrophysics Data System (ADS)

The matter content of jets in active galactic nuclei is examined in a new way. We model the dynamical expansion of its cocoon embedded in the intra-cluster medium (ICM). By comparing the observed shape of the cocoon with that expected from the theoretical model, we estimate the total pressure (Pc) and electron temperature (Te) of the cocoon. The number density of the total electrons (ne-) is constrained by using the non-thermal spectrum of the hot spot and the analysis of the momentum balance between the jet thrust and the rum pressure of ICM. Together with the obtained Pc, Te and ne-, we constrain the matter content in the jets. We find that, in the case of Cygnus A, the ratio of number density of protons to that of electrons is of order of 10-3 . This implies the existence of a large number of positron in the jet.

Kino, M.; Kawakatu, N.

2005-11-01

236

Impinging axisymmetric jet  

Microsoft Academic Search

The characteristics of an axisymmetric air jet with a fully developed pipe flow exit condition impinging vertically onto a flat plate was studied experimentally using hot wire anemometry and flow visualization. The jet to plate spacings ranged from one to five jet diameters and Reynold numbers (based on jet centerline velocity and jet diameter) varied from 40 to 23000. A

Savas Aydore

1991-01-01

237

Measurement of Z \\/ ? ? + jet + X angular distributions in p p ¯ collisions at s = 1.96 TeV  

Microsoft Academic Search

We present the first measurements at a hadron collider of differential cross sections for Z\\/??+jet+X production in ??(Z,jet), |?y(Z,jet)| and |yboost(Z+jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative

V. M. Abazov; B. Abbott; M. Abolins; B. S. Acharya; M. Adams; T. Adams; E. Aguilo; M. Ahsan; G. D. Alexeev; G. Alkhazov; A. Alton; G. Alverson; G. A. Alves; L. S. Ancu; M. S. Anzelc; M. Aoki; Y. Arnoud; M. Arov; M. Arthaud; A. Askew; B. Åsman; O. Atramentov; C. Avila; J. BackusMayes; F. Badaud; L. Bagby; B. Baldin; D. V. Bandurin; S. Banerjee; E. Barberis; A.-F. Barfuss; P. Bargassa; P. Baringer; J. Barreto; J. F. Bartlett; U. Bassler; D. Bauer; S. Beale; A. Bean; M. Begalli; M. Begel; C. Belanger-Champagne; L. Bellantoni; A. Bellavance; J. A. Benitez; S. B. Beri; G. Bernardi; R. Bernhard; I. Bertram; M. Besançon; R. Beuselinck; V. A. Bezzubov; P. C. Bhat; V. Bhatnagar; G. Blazey; S. Blessing; K. Bloom; A. Boehnlein; D. Boline; T. A. Bolton; E. E. Boos; G. Borissov; T. Bose; A. Brandt; R. Brock; G. Brooijmans; A. Bross; D. Brown; X. B. Bu; D. Buchholz; M. Buehler; V. Buescher; V. Bunichev; S. Burdin; T. H. Burnett; C. P. Buszello; P. Calfayan; B. Calpas; S. Calvet; J. Cammin; M. A. Carrasco-Lizarraga; E. Carrera; W. Carvalho; B. C. K. Casey; H. Castilla-Valdez; S. Chakrabarti; D. Chakraborty; K. M. Chan; A. Chandra; E. Cheu; D. K. Cho; S. W. Cho; S. Choi; B. Choudhary; T. Christoudias; S. Cihangir; D. Claes; J. Clutter; M. Cooke; W. E. Cooper; M. Corcoran; F. Couderc; M.-C. Cousinou; D. Cutts; M. ?wiok; A. Das; G. Davies; K. De; S. J. de Jong; E. De La Cruz-Burelo; K. DeVaughan; F. Déliot; M. Demarteau; R. Demina; D. Denisov; S. P. Denisov; S. Desai; H. T. Diehl; M. Diesburg; A. Dominguez; T. Dorland; A. Dubey; L. V. Dudko; L. Duflot; D. Duggan; A. Duperrin; S. Dutt; A. Dyshkant; M. Eads; D. Edmunds; J. Ellison; V. D. Elvira; Y. Enari; S. Eno; M. Escalier; H. Evans; A. Evdokimov; V. N. Evdokimov; G. Facini; A. V. Ferapontov; T. Ferbel; F. Fiedler; F. Filthaut; W. Fisher; H. E. Fisk; M. Fortner; H. Fox; S. Fu; S. Fuess; T. Gadfort; C. F. Galea; A. Garcia-Bellido; V. Gavrilov; P. Gay; W. Geist; W. Geng; C. E. Gerber; Y. Gershtein; D. Gillberg; G. Ginther; B. Gómez; A. Goussiou; P. D. Grannis; S. Greder; H. Greenlee; Z. D. Greenwood; E. M. Gregores; G. Grenier; Ph. Gris; J.-F. Grivaz; A. Grohsjean; S. Grünendahl; M. W. Grünewald; F. Guo; J. Guo; G. Gutierrez; P. Gutierrez; A. Haas; P. Haefner; S. Hagopian; J. Haley; I. Hall; R. E. Hall; L. Han; K. Harder; A. Harel; J. M. Hauptman; J. Hays; T. Hebbeker; D. Hedin; J. G. Hegeman; A. P. Heinson; U. Heintz; C. Hensel; I. Heredia-De La Cruz; K. Herner; G. Hesketh; M. D. Hildreth; R. Hirosky; T. Hoang; J. D. Hobbs; B. Hoeneisen; M. Hohlfeld; S. Hossain; P. Houben; Y. Hu; Z. Hubacek; N. Huske; V. Hynek; I. Iashvili; R. Illingworth; A. S. Ito; S. Jabeen; M. Jaffré; S. Jain; K. Jakobs; D. Jamin; R. Jesik; K. Johns; C. Johnson; M. Johnson; D. Johnston; A. Jonckheere; P. Jonsson; A. Juste; E. Kajfasz; D. Karmanov; P. A. Kasper; I. Katsanos; V. Kaushik; R. Kehoe; S. Kermiche; N. Khalatyan; A. Khanov; A. Kharchilava; Y. N. Kharzheev; D. Khatidze; M. H. Kirby; M. Kirsch; B. Klima; J. M. Kohli; J.-P. Konrath; A. V. Kozelov; J. Kraus; T. Kuhl; A. Kumar; A. Kupco; T. Kur?a; V. A. Kuzmin; J. Kvita; F. Lacroix; D. Lam; S. Lammers; G. Landsberg; P. Lebrun; H. S. Lee; W. M. Lee; A. Leflat; J. Lellouch; L. Li; Q. Z. Li; S. M. Lietti; J. K. Lim; D. Lincoln; J. Linnemann; V. V. Lipaev; R. Lipton; Y. Liu; Z. Liu; A. Lobodenko; M. Lokajicek; P. Love; H. J. Lubatti; R. Luna-Garcia; A. L. Lyon; A. K. A. Maciel; D. Mackin; P. Mättig; R. Magaña-Villalba; P. K. Mal; S. Malik; V. L. Malyshev; Y. Maravin; B. Martin; R. McCarthy; C. L. McGivern; M. M. Meijer; A. Melnitchouk; L. Mendoza; D. Menezes; P. G. Mercadante; M. Merkin; K. W. Merritt; A. Meyer; J. Meyer; N. K. Mondal; R. W. Moore; T. Moulik; G. S. Muanza; M. Mulhearn; O. Mundal; L. Mundim; E. Nagy; M. Naimuddin; M. Narain; H. A. Neal; J. P. Negret; P. Neustroev; H. Nilsen; H. Nogima; S. F. Novaes; T. Nunnemann; G. Obrant; C. Ochando; D. Onoprienko; J. Orduna; N. Oshima; N. Osman; J. Osta; R. Otec; G. J. Otero y Garzón; M. Owen; M. Padilla; P. Padley; M. Pangilinan; N. Parashar; S.-J. Park; J. Parsons; R. Partridge; N. Parua; A. Patwa; B. Penning; M. Perfilov; K. Peters; Y. Peters; P. Pétroff; R. Piegaia; J. Piper; M.-A. Pleier; P. L. M. Podesta-Lerma; V. M. Podstavkov; Y. Pogorelov; M.-E. Pol; P. Polozov; A. V. Popov; M. Prewitt; S. Protopopescu; J. Qian; A. Quadt; B. Quinn; A. Rakitine; M. S. Rangel; K. Ranjan; P. N. Ratoff; P. Renkel; P. Rich; M. Rijssenbeek; I. Ripp-Baudot; F. Rizatdinova; S. Robinson; M. Rominsky; C. Royon; P. Rubinov; R. Ruchti; G. Safronov; G. Sajot; A. Sánchez-Hernández; M. P. Sanders; B. Sanghi; G. Savage; L. Sawyer; T. Scanlon; D. Schaile; R. D. Schamberger; Y. Scheglov; H. Schellman; T. Schliephake; S. Schlobohm; C. Schwanenberger; R. Schwienhorst; J. Sekaric; H. Severini; E. Shabalina; M. Shamim; V. Shary; A. A. Shchukin; R. K. Shivpuri; V. Siccardi; V. Simak

2010-01-01

238

Analysis of Thrust and Flow Augmentation of a Coanda Nozzle.  

National Technical Information Service (NTIS)

In order to evaluate the performance of a Coanda Nozzle and to determine its thrust and pumping capabilities, a series of tests were conducted on a Coanda Nozzle. The results showed that the nozzle was capable of creating thrust augmentation of about 1.25...

E. L. Victory

1965-01-01

239

Friction torque in grease lubricated thrust ball bearings  

Microsoft Academic Search

Thrust ball bearings lubricated with several different greases were tested on a modified Four-Ball Machine, where the Four-Ball arrangement was replaced by a bearing assembly. The friction torque and operating temperatures in a thrust ball bearing were measured during the tests. At the end of each test a grease sample was analyzed through ferrographic techniques in order to quantify and

Tiago Cousseau; Beatriz Graça; Armando Campos; Jorge Seabra

2011-01-01

240

Numerical simulation of thrust generating flow past a pitching airfoil  

Microsoft Academic Search

Earlier analytical and experimental studies predict that pitching motions at high frequency can generate thrust on the airfoil. The present work is an effort towards a systematic understanding of the influence of various parameters on thrust generation from a harmonically pitching airfoil. Quantitative instantaneous force computations have been discussed together with qualitative vortex patterns using a 2-D discrete vortex simulation

Sunetra Sarkar; Kartik Venkatraman

2006-01-01

241

Variation of pore fabric across a fold-thrust structure  

Microsoft Academic Search

Variations of pore orientation, pore shape, porosity, and hydraulic permeability, within a siltstone unit of a fold-thrust structure, are determined using magnatic pore fabric analysis, mercury injection porosimetry, and scanning electron microscopy (SEM). While samples in the foreland show evidence for the preservation of depositional pore geometry, the progressively deformed thrust sheet reveals increasingly oblate pore fabric anisotropy with microcrack

Sebastian Pfleiderer; Catherine Kissel

1994-01-01

242

Electronics Engineering Department Thrust Area report FY'84  

SciTech Connect

This report describes the work of the Electronics Engineering Department Thrust Areas for FY'84: diagnostics and microelectronic engineering; signal and control engineering; microwave and pulsed power engineering; computer-aided engineering; engineering modeling and simulation; and systems engineering. For each Thrust Area, an overview and a description of the goals and achievements of each project is provided.

Minichino, C.; Phelps, P.L. (eds.)

1984-01-01

243

ONBOARD THRUST DIRECTION COMPUTATION ALGORITHM FOR LOW-THRUST MINIMUM-TIME TRANSFERS  

Microsoft Academic Search

Efficient tools have been developed to solve low-thrust minimum-time transfers between arbitrary orbits around the Earth. The tool developed by CNES, called MIPELEC, is based on indirect method and uses the Pontryagin's maximum principle. MIPELEC solve the optimal control problem by obtaining the solution to the corresponding two-point boundary value problem (TPBVP). Averaging technique are used to solve the TPBVP

J. Fourcade

244

Measurements of the b quark forward-backward asymmetry around the Z $^0$ peak using jet charge and vertex charge  

Microsoft Academic Search

The b quark forward-backward asymmetry has been measured using approximately four million hadronic Z$^0$ decays collected with the OPAL detector at LEP. Both jet charge and vertex charge were used to estimate whether the b quark was produced in the forward or backward thrust hemisphere. The measured values corrected to the hadron-level thrust axis are \\\\[ \\\\begin{array}{llll} A^{\\\\rm b}_{\\\\rm FB}

Gideon Alexander; J Allison; N Altekamp; K A Ametewee; K J Anderson; S Anderson; S Arcelli; S Asai; D A Axen; Georges Azuelos; A H Ball; E Barberio; R J Barlow; R Bartoldus; J Richard Batley; J Bechtluft; C Beeston; T Behnke; A N Bell; K W Bell; G Bella; Stanislaus Cornelius Maria Bentvelsen; P Berlich; Siegfried Bethke; O Biebel; A Biguzzi; S D Bird; Volker Blobel; Ian J Bloodworth; J E Bloomer; M Bobinski; P Bock; H M Bosch; M Boutemeur; B T Bouwens; S Braibant; R M Brown; Helfried J Burckhart; C Burgard; R Bürgin; P Capiluppi; R K Carnegie; A A Carter; J R Carter; C Y Chang; D G Charlton; D Chrisman; P E L Clarke; I Cohen; J E Conboy; O C Cooke; M Cuffiani; S Dado; C Dallapiccola; G M Dallavalle; S De Jong; L A del Pozo; Klaus Desch; M S Dixit; E do Couto e Silva; M Doucet; E Duchovni; G Duckeck; I P Duerdoth; D Eatough; J E G Edwards; P G Estabrooks; H G Evans; M Evans; Franco Luigi Fabbri; M Fanti; P Fath; A A Faust; F Fiedler; M Fierro; H M Fischer; R Folman; D G Fong; M Foucher; A Fürtjes; P Gagnon; A Gaidot; J W Gary; J Gascon; S M Gascon-Shotkin; N I Geddes; C Geich-Gimbel; F X Gentit; T Geralis; G Giacomelli; P Giacomelli; R Giacomelli; V Gibson; W R Gibson; D M Gingrich; D A Glenzinski; J Goldberg; M J Goodrick; W Gorn; C Grandi; E Gross; Jacob Grunhaus; M Gruwé; C Hajdu; G G Hanson; M Hansroul; M Hapke; C K Hargrove; P A Hart; C Hartmann; M Hauschild; C M Hawkes; R Hawkings; Richard J Hemingway; M Herndon; G Herten; R D Heuer; M D Hildreth; J C Hill; S J Hillier; T Hilse; P R Hobson; R James Homer; A K Honma; D Horváth; R Howard; R E Hughes-Jones; D E Hutchcroft; P Igo-Kemenes; D C Imrie; M R Ingram; K Ishii; A Jawahery; P W Jeffreys; H Jeremie; Martin Paul Jimack; A Joly; C R Jones; G Jones; M Jones; R W L Jones; U Jost; P Jovanovic; T R Junk; D A Karlen; K Kawagoe; T Kawamoto; Richard K Keeler; R G Kellogg; B W Kennedy; J Kirk; S Kluth; T Kobayashi; M Kobel; D S Koetke; T P Kokott; M Kolrep; S Komamiya; T Kress; P Krieger; J Von Krogh; P Kyberd; G D Lafferty; H Lafoux; R Lahmann; W P Lai; D Lanske; J Lauber; S R Lautenschlager; J G Layter; D Lazic; A M Lee; E Lefebvre; Daniel Lellouch; J Letts; L Levinson; C Lewis; S L Lloyd; F K Loebinger; G D Long; Michael J Losty; J Ludwig; A Macchiolo; A L MacPherson; A Malik; M Mannelli; S Marcellini; C Markus; A J Martin; J P Martin; G Martínez; T Mashimo; W Matthews; P Mättig; W J McDonald; J A McKenna; E A McKigney; T J McMahon; A I McNab; R A McPherson; F Meijers; S Menke; F S Merritt; H Mes; J Meyer; Aldo Michelini; G Mikenberg; D J Miller; R Mir; W Mohr; A Montanari; T Mori; M Morii; U Müller; K Nagai; I Nakamura; H A Neal; B Nellen; B Nijjhar; R Nisius; S W O'Neale; F G Oakham; F Odorici; H O Ögren; N J Oldershaw; T Omori; M J Oreglia; S Orito; J Pálinkás; G Pásztor; J R Pater; G N Patrick; J Patt; M J Pearce; S Petzold; P Pfeifenschneider; J E Pilcher; James L Pinfold; D E Plane; P R Poffenberger; B Poli; A Posthaus; H Przysiezniak; D L Rees; D Rigby; S Robertson; S A Robins; N L Rodning; J M Roney; A M Rooke; E Ros; A M Rossi; M Rosvick; P Routenburg; Y Rozen; K Runge; O Runólfsson; U Ruppel; D R Rust; R Rylko; K Sachs; E Sarkisyan-Grinbaum; M Sasaki; C Sbarra; A D Schaile; O Schaile; F Scharf; P Scharff-Hansen; P Schenk; B Schmitt; S Schmitt; M Schröder; H C Schultz-Coulon; M Schulz; M Schumacher; P Schütz; W G Scott; T G Shears; B C Shen; C H Shepherd-Themistocleous; P Sherwood; G P Siroli; A Sittler; A Skillman; A Skuja; A M Smith; T J Smith; G A Snow; Randall J Sobie; S Söldner-Rembold; R W Springer; M Sproston; A Stahl; M Steiert; K Stephens; J Steuerer; B Stockhausen; D Strom; P Szymanski; R Tafirout; S D Talbot; S Tanaka; P Taras; S Tarem; M Thiergen; M A Thomson; E Von Törne; S Towers; I Trigger; T Tsukamoto; E Tsur; A S Turcot; M F Turner-Watson; P Utzat; R Van Kooten; G Vasseur; M Verzocchi; P Vikas; M G Vincter; E H Vokurka; F Wäckerle; A Wagner; C P Ward; D R Ward; J J Ward; P M Watkins; A T Watson; N K Watson; P S Wells; N Wermes; J S White; B Wilkens; G W Wilson; J A Wilson; G Wolf; S A Wotton; T R Wyatt; S Yamashita; G Yekutieli; V Zacek; D Zer-Zion

1997-01-01

245

Static thrust recovery of PAR craft on solid surfaces  

NASA Astrophysics Data System (ADS)

Power-Augmented-Ram Vehicles belong to a new class of ground-effect machines with hybrid support. Recovered static thrust and static lift on solid surfaces are important amphibious characteristics of this craft. Experimental data for the static thrust recovery and the transition to a hovering mode are obtained in the tests with a vehicle model on two types of ground surface and with variable engine thrust and flap trailing-edge gap. The uphill surface and increased mass of the model demonstrate reductions in thrust recovery. A comparison with a two-dimensional potential-flow theory is presented. The static thrust accumulation, identified in the pre-hovering regime of a model on solid surface, does not significantly benefit the low-speed forward motion.

Matveev, K. I.

2008-08-01

246

Controlling pulsatile jet formation number with variable diameter exit nozzle for maximum impulse generation  

NASA Astrophysics Data System (ADS)

Both jellyfish and Squid propel themselves by ejecting high momentum vortex rings. A set of vortex ring generating thrusters were developed and tested for application in underwater vehicle propulsion. Vortex rings generated from a steady piston cylinder mechanism have a universal formation time, known as the formation number (Gharib et al. 1998), associated with reaching maximum circulation, where the vortex ring separates from its trailing shear flow. The non-dimensional jet formation time (also called the stroke ratio) plays a key role in the thrust output of the device; since thrusters operating above the formation number re-ingest the trailing jet. A variable diameter exit nozzle was used to increase the formation number of the jet to maximize thrust (which is a technique observed in squid and jellyfish locomotion). Visualization studies confirmed the ability to delay the onset of ring ``pinch-off'', using a variable nozzle, and the thrust was empirically shown to achieve a higher maximum. Additionally, a fluid slug model which was developed to predict the thrust output was adapted to incorporate a changing nozzle diameter. This model was verified with the empirical thrust data and was again shown to be accurate for stroke ratios below the formation number.

Krieg, Mike; Thomas, Tyler; Mohseni, Kamran

2009-11-01

247

Geometry and lateral slip distribution along large thrust fault systems  

SciTech Connect

Quantitative relationships between fold and fault shapes allow detailed analyses of thrust fault geometries and slip histories. Fold limbs (kink bands) that grow by axial surface migration above bends in thrust faults record dip-slip motion. Folds imaged in high-resolution seismic reflection profiles record this total fault dip-slip and reflect causative thrust fault geometry. Growth (syntectonic) strata deposited during the active history of underlying thrusts develop limb widths equal to the amount of fault dip-slip since their deposition. Therefore, narrowing upward kink bands (growth triangles) form as sediments deposited earlier in the slip history record wider limb widths than do sediments deposited later. Ages of selected syntectonic strata (determined independently) in growth triangles allow estimates of long term fault-slip rates. Maps of axial surfaces that bound kink bands highlight changes in thrust fault geometry along strike and record lateral fault-slip distribution. In addition, end and offsets of kink bands in map view highlight fault terminations and lateral changes in thrust fault geometry. Detailed analyses of fold and fault geometries constrain balanced, three-dimensional structural models that show how large thrust faults develop and slip through time. These models and cross sections integrate G.P.S. measurements and seismicity from active thrust fault systems. Lateral variations in fold shape caused by changes in thrust fault geometry may form lateral closure along fold trends that trap hydrocarbons. Combined, fault slip rates and fault geometry yield estimates of the size and recurrence of potentially damaging earthquakes on blind thrust fault systems.

Shaw, J.H.; Genovese, P.W.; Suppe, J. (Princeton Univ., NJ (United States). Dept. of Geological and Geophysical Sciences)

1992-01-01

248

The smallest man-made jet engine.  

PubMed

The design of catalytic engines powered by chemical fuels is an exciting and emerging field in multidisciplinary scientific communities. Recent progress in nanotechnology has enabled scientists to shrink the size of macroengines down to microscopic, but yet powerful, engines. Since a couple of years ago, we have reported our progress towards the control and application of catalytic microtubular engines powered by the breakdown of hydrogen peroxide fuel which produces a thrust of oxygen bubbles. Efforts were undertaken in our group to prove whether the fabrication of nanoscale jets is possible. Indeed, the smallest jet engine (600 nm in diameter and 1 picogram of weight) was synthesized based on heteroepitaxially grown layers. These nanojets are able to self-propel in hydrogen peroxide solutions and are promising for the realisation of multiple tasks. PMID:21898776

Sanchez, Samuel; Solovev, Alexander A; Harazim, Stefan M; Deneke, Christoph; Mei, Yong Feng; Schmidt, Oliver G

2011-09-06

249

14 CFR 23.934 - Turbojet and turbofan engine thrust reverser systems tests.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Turbojet and turbofan engine thrust reverser systems tests... General § 23.934 Turbojet and turbofan engine thrust reverser systems tests. Thrust reverser systems of turbojet or turbofan engines must meet the...

2010-01-01

250

14 CFR 23.934 - Turbojet and turbofan engine thrust reverser systems tests.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Turbojet and turbofan engine thrust reverser systems tests... General § 23.934 Turbojet and turbofan engine thrust reverser systems tests. Thrust reverser systems of turbojet or turbofan engines must meet the...

2013-01-01

251

14 CFR 23.934 - Turbojet and turbofan engine thrust reverser systems tests.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Turbojet and turbofan engine thrust reverser systems tests... General § 23.934 Turbojet and turbofan engine thrust reverser systems tests. Thrust reverser systems of turbojet or turbofan engines must meet the...

2009-01-01

252

Minimum Propellant Solution to an Orbit-to-Orbit Transfer Using a Low Thrust Propulsion System.  

National Technical Information Service (NTIS)

The Space Exploration Initiative is considering the use of low thrust (nuclear electric, solar electric) and intermediate thrust (nuclear thermal) propulsion systems for transfer to Mars and back. Due to the duration of such a mission, a low thrust minimu...

S. S. Cobb

1991-01-01

253

Velocity field measurement of a round jet using quantitative schlieren.  

PubMed

This paper utilizes the background oriented schlieren (BOS) technique to measure the velocity field of a variable density round jet. The density field of the jet is computed based on the light deflection created during the passage of light through the understudy jet. The deflection vector estimation was carried out using phase-based optical flow algorithms. The density field is further exploited to extract the axial and radial velocity vectors with the aid of continuity and energy equations. The experiment is conducted at six different jet-exit temperature values. Additional turbulence parameters, such as velocity variance and power spectral density of the vector field, are also computed. Finally, the measured velocity parameters are compared with the hot wire anemometer measurements and their correlation is displayed. PMID:21343981

Iffa, Emishaw D; Aziz, A Rashid A; Malik, Aamir S

2011-02-10

254

Velocity field measurement of a round jet using quantitative schlieren  

SciTech Connect

This paper utilizes the background oriented schlieren (BOS) technique to measure the velocity field of a variable density round jet. The density field of the jet is computed based on the light deflection created during the passage of light through the understudy jet. The deflection vector estimation was carried out using phase-based optical flow algorithms. The density field is further exploited to extract the axial and radial velocity vectors with the aid of continuity and energy equations. The experiment is conducted at six different jet-exit temperature values. Additional turbulence parameters, such as velocity variance and power spectral density of the vector field, are also computed. Finally, the measured velocity parameters are compared with the hot wire anemometer measurements and their correlation is displayed.

Iffa, Emishaw D.; Aziz, A. Rashid A.; Malik, Aamir S.

2011-02-10

255

Kinematic history of the Meade Thrust based on provenance of the Bechler conglomerate at Red Mountain, Idaho, Sevier Thrust Belt  

NASA Astrophysics Data System (ADS)

With up to ˜45 km of slip, the Meade thrust fault in southeastern Idaho is one of the major thrusts in the Sevier thrust belt, yet its age of displacement has remained enigmatic because of the lack of a derivative synorogenic deposit. We propose that the synorogenic conglomerate produced by initial Meade thrusting crops out on Red Mountain, in southeastern Idaho, ˜1.5 km east of the present trace of the Meade thrust. This conglomerate historically has been considered part of the Ephraim Formation of the Lower Cretaceous Gannett Group, but we suggest that it is a conglomeratic facies of the Bechler Formation localized to the area of Red Mountain. Regional stratigraphic considerations and paleontological dates from underlying and overlying strata indicate that the Bechler conglomerate facies (BCF) is Aptian in age. The BCF is 850 m thick and consists of pebble- to boulder-conglomerate, sandstone, and mudrock deposited by fluvial and mass flow processes on medial to distal parts of an alluvial fan. Paleocurrent data indicate an eastward, fan-shaped dispersal pattern. The BCF contains clasts of micritic limestone, chert-pebble conglomerate, and cherty litharenite that were derived from the Ephraim Formation. In addition, the conglomerate contains abundant clasts of Ordovician, Carboniferous, and lower Mesozoic rocks that crop out on both the Meade thrust sheet and the Paris thrust sheet ˜25-30 km to the west. The base of the BCF is marked by a local 27° angular unconformity on top of the Ephraim Formation. The BCF contains intraformational, progressively rotated angular unconformities, internal growth folds, and minor dip discontinuities that were produced by simultaneous folding and sediment accumulation on the proximal footwall of the Meade thrust. Provenance modeling indicates that the BCF was derived from Mesozoic strata that were exposed along the frontal part of the Meade thrust sheet and from Paleozoic strata that were coevally exposed in the hindward located Paris thrust sheet. Topography on the Paris sheet was rejuvenated as it was carried passively over a major ramp in the Meade thrust. Provenance and structural data are combined to produce an incremental, bulk-rock retrodeformation of initial Meade displacement. Clasts of Jurassic Twin Creek Limestone with pressure-solution cleavage in the lower part of the BCF indicate that an episode of layer-parallel shortening occurred in the Meade hanging wall prior to Meade displacement; this may have been related to emplacement of the Paris thrust sheet. The BCF recorded ˜6 km of initial Meade-related shortening by thrust slip and fault-propagation folding during Aptian time. Illite crystallinity, systematic fracture sets in the Ephraim Formation and BCF, finite strain in Meade footwall and hanging wall rocks, and thermal models by previous workers indicate that the Meade thrust sheet ultimately overrode the BCF and other footwall rocks, probably during Albian-Cenomanian time. The BCF and the Meade thrust were folded during slip on thrust faults related to the northern Crawford thrust during Coniacian time. A revised interpretation of Gannett Group provenance throughout the thrust belt suggests that the Ephraim Formation was derived from both the Paris thrust sheet and an older, hindward located thrust sheet. The Bechler was derived from the Meade and Paris sheets.

Decelles, P. G.; Pile, H. T.; Coogan, J. C.

1993-12-01

256

Development of a Jet Engine Experiment for the Energy Systems Laboratory  

Microsoft Academic Search

Recently, a jet engine experiment was added to the Energy Systems Laboratory at Kettering University (formerly GMI). The educational objectives of this experiment are: to familiarize the students with the operation of a turbojet engine, the theory behind the thermodynamic processes involved, and the linear momentum equation; to determine theoretical and measured engine thrust and the efficiencies of the compressor,

A. Pourmovahed; C. M. Jeruzal; K. D. Brinker

257

Evaluation of thrust measurement techniques for dielectric barrier discharge actuators  

NASA Astrophysics Data System (ADS)

Despite its popularity in the recent literature, plasma actuators lack a consistent study to identify limitations, and remedy thereof, of various thrust measurement techniques. This paper focuses on comparing two different experimental techniques commonly used to measure the global, plasma-induced thrust. A force balance is used to make a direct measurement of the thrust produced, which is then compared with a control volume analysis on data obtained through particle image velocimetry. The local velocity measured by particle image velocimetry is also validated with a fine-tip pressure probe. For the direct thrust measurements, the effect of varying the actuator plate length upon which the induced flow acts is investigated. The results from these tests show that the length of the actuator plate is most influential at higher voltages with the measured thrust increasing as much as 20 % for a six times reduction in the length of the plate. For the indirect thrust measurement, the influence of the control volume size is analyzed. When the two methods are compared against each other, good agreement is found when the control volume size has a sufficient downstream extent. Also, the discharge length is optically measured using visible light emission. A linear correlation is found between the discharge length and the thrust measurements for the actuator configurations studied. Finally, the energy conversion efficiency curve for a representative actuator is also presented.

Durscher, Ryan; Roy, Subrata

2012-10-01

258

Effect of Tongue Thrust Swallowing on Position of Anterior Teeth  

PubMed Central

Background and aims There is no consensus about the effect of tongue thrusting on incisor position. The purpose of this study was to evaluate the position of anterior teeth in growing children with tongue thrust swallowing. Materials and methods In the present study 193 subjects with an age range of 9 to 13 years participated. All the patients were examined by a trained investigator and those having tongue thrust swallowing were selected and the position of their anterior teeth was compared with a control group consisting of 36 subjects with normal occlusion. Data was analyzed by independent sample t-test. Results Among the 193 students who were examined in this study, 10 cases (5%) were diagnosed to be tongue thrusters. Overjet was significantly increased in tongue thrust individuals (P < 0.05), while the other variables were not statistically different from the controls (P > 0.05). Conclusion The results indicated that tongue thrust may have an environmental effect on dentofacial structures. Considering the high incidence of tongue thrust in orthodontic patients, it is suggested that dental practitioners observe patients of all ages and those in all stages of orthodontic treatment for evidence of tongue thrust swallowing.

Jalaly, Tahereh; Ahrari, Farzaneh; Amini, Foroozandeh

2009-01-01

259

Thrusting Evolution in the Southern Cordillera Oriental (Northern Argentine Andes)  

NASA Astrophysics Data System (ADS)

Growth strata and unconformities observed in the Neogene-Quaternary synorogenic sediments in the southern Cordillera Oriental of northern Argentine Andes demonstrate that deformation migrated eastwards from the Puna to the Santa Bárbara system, as it is accepted and well documented. However, the newly described growth sequences and unconformities allow us to unravel a more precise timing of the structures and determining the partitioning of the deformation through time into the thrust and fold wedge. Thrust evolution was mostly controlled by the reactivation of earlier extensional faults of the Salta Rift Basin. The geometry of the inverted structures combined with the general forward migration of the deformation, resulted in different thrust sequences. The foreland dipping imbricate stack of the western Cordillera Oriental developed forwards during Middle-Upper Miocene, giving rise to a break back thrusting sequence. Thrust propagation rate increased at Upper Miocene- Lower Pliocene times when the eastern part of the Cordillera Oriental developed. At that time a widespread deformation and synchronous thrusting occurred in the Cordillera Oriental. Afterwards, deformation was mostly restricted in the eastern part of the Cordillera Oriental. Finally, during the Quaternary deformation involved a wider zone, including all the Cordillera Oriental and the Santa Barbara System, leading to the reactivation of previously developed thrusts.

Carrera, N.; Munoz, J.

2007-05-01

260

Reconciling Geodetic and Geologic Rates in Fold and Thrust Belts  

NASA Astrophysics Data System (ADS)

Although the scales of observation are not the same, thrust fault slip rates based on dated sediments often yield values an order less than those derived from geodesy (cm vs mm/yr). Moreover, the patterns of present surface motions compared to those accumulated over millions of years are somewhat different. For instance, results from the Idaho-Wyoming-Utah thrust belt and the Andes suggest that the initiation of thrusting progresses from hinterland to foreland. Certainty worsens with age because complexity of deformation increases with age, i.e., initiation of younger, deeper thrust fault rejuvenates older, higher ones and thrust sheets may move several times. Although preservation degrades toward the hinterland, thrusting appears to finally turn off from foreland to hinterland. Evidence for out-of-sequence thrusting is not common. Where timing data are unusually good (e.g., Pyrenees), displacement was evidently not constant in either space or time. This episodicity at times scales of 106 yrs may extend to individual thrust sheets. By contrast, geodetic data - which include both elastic strain accumulation and creep - indicate that all structures in southern Taiwan are moving. The frontal portion is slightly more active than areas to the east. Current geodetic motions are largely normal to local thrust fault traces, even coseismic slip such as that of the Chi-Chi earthquake. Fold growth may be nearly as important as fault slip, although greater data density is required. The discrepancy between geodetic and geologic rates may be attributed to the fact that in the two cases different quantities or aggregates of them are being measured. The difference in patterns is attributable to the different time scales of observation.

Wiltschko, D. V.

2007-12-01

261

Cretaceous biostratigraphy in the Wyoming thrust belt.  

USGS Publications Warehouse

In the Cretaceous section of the thrust belt, fossils are especially useful for dating and correlating repetitive facies of different ages in structurally complex terrain. The biostratigraphic zonation for the region is based on megafossils (chiefly ammonites) , which permit accurate dating and correlation of outcrop sections, and which have been calibrated with the radiometric time scale for the Western Interior. Molluscan and vertebrate zone fossils are difficult to obtain from the subsurface, however, and ammonites are restricted to rocks of marine origin. Palynomorphs (plant microfossils) have proven to be the most valuable fossils in the subsurface because they can be recovered from drill cuttings. Palynomorphs also are found in both marine and nonmarine rocks and can be used for correlation between facies. Stratigraphic ranges of selected Cretaceous marine and nonmarine palynomorphs in previously designated reference sections in Fossil Basin, Wyoming are correlated with the occurrence of ammonites and other zone fossils in the same sections. These correlations can be related to known isotopic ages, and they contribute to the calibration of palynomorph ranges in the Cretaceous of the Western Interior. -from Authors

Nichols, D. J.; Jacobson, S. R.

1982-01-01

262

Experimental Investigation of Thrust Faults in Homalite  

NASA Astrophysics Data System (ADS)

A sound interplay between experimental observations and numerical simulations can reveal a much greater insight into a scientific problem than either methodology alone, where numerics may direct the next experiment or vise-versa. With this motivation, experiments are designed to study the ground motion of thrust faults near the fault trace and to compare with true-to-life numerical simulation results. Through the application of an external load with a press to a thin sheet of Homalite, a high-density polymer, and discharging a capacitor across a wire, slip is initiated along a carefully treated interface. Several key parameters such as the angle of the interface and the applied load may be varied to achieve fundamentally different wave phenomenon, namely a super shear or sub-Rayleigh event. Laser vibrometers are used to record the velocity normal to the free surface on the hanging wall and the footwall. With high-speed cameras, photoelastic fringes are obtained in transmission through the Homalite slab, outputting information about the stress state in the material. Discoveries on the material response to the applied wave field are possible with the information from the photoelastic images in conjunction with the velocity traces, especially in the differences between a super shear and a sub Rayleigh event. Experimental results validate the salient features of the numerical simulations in 2D and even more closely in 3D.

Gabuchian, V.; Rosakis, A.; Lapusta, N.; Oglesby, D. D.

2010-12-01

263

Precision jet substructure from boosted event shapes.  

PubMed

Jet substructure has emerged as a critical tool for LHC searches, but studies so far have relied heavily on shower Monte Carlo simulations, which formally approximate QCD at the leading-log level. We demonstrate that systematic higher-order QCD computations of jet substructure can be carried out by boosting global event shapes by a large momentum Q and accounting for effects due to finite jet size, initial-state radiation (ISR), and the underlying event (UE) as 1/Q corrections. In particular, we compute the 2-subjettiness substructure distribution for boosted Z?qq[over ¯] events at the LHC at next-to-next-to-next-to-leading-log order. The calculation is greatly simplified by recycling known results for the thrust distribution in e(+)e(-) collisions. The 2-subjettiness distribution quickly saturates, becoming Q independent for Q > or approximately equal to 400 GeV. Crucially, the effects of jet contamination from ISR/UE can be subtracted out analytically at large Q without knowing their detailed form. Amusingly, the Q=? and Q=0 distributions are related by a scaling by e up to next-to-leading-log order. PMID:23002825

Feige, Ilya; Schwartz, Matthew D; Stewart, Iain W; Thaler, Jesse

2012-08-30

264

Electrically Driven Jets  

Microsoft Academic Search

Fine jets of slightly conducting viscous fluids and thicker jets or drops of less viscous ones can be drawn from conducting tubes by electric forces. As the potential of the tube relative to a neighbouring plate rises, viscous fluids become nearly conical and fine jets come from the vertices. The potentials at which these jets or drops first appear was

Geoffrey Taylor

1969-01-01

265

The Thrust Performance and Losses of a Family of Nozzles.  

National Technical Information Service (NTIS)

This study was made to identify and quantify the internal losses that occur in the primary flow nozzles of thrust augmenting ejectors. Fifteen individually fabricated slot nozzles were designed to have different internal geometries. Tests were conducted w...

B. P. Quinn K. K. Joshi

1975-01-01

266

53. THRUST SECTION HEATER AND GASEOUS NITROGEN PURGE CONTROLS ON ...  

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

53. THRUST SECTION HEATER AND GASEOUS NITROGEN PURGE CONTROLS ON EAST SIDE OF LAUNCH DECK. LAUNCHER IN BACKGROUND. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

267

Thrust Characteristics of Water Rocket and Their Improvement  

NASA Astrophysics Data System (ADS)

The propulsive characteristics of water rockets are analyzed theoretically and experimentally. The unsteady thrust force acting on a PET bottle and the air pressure inside the bottle are measured simultaneously by the thrust test stand we have developed. The semi-empirical thrust history is obtained utilizing the air pressure history and it is compared with the measured thrust history. The results show qualitative agreement. The observation of the flow inside bottle by a high-speed video camera shows that the air precedes water when it is about to be discharged entirely. We have developed a flow regulator attached to the nozzle cap to reduce the precursor air discharge that is considered as a result of the swirling flow inside the bottle. The experimental results show that the air discharge and the body vibration are suppressed effectively.

Watanabe, Rikio; Tomita, Nobuyuki; Takemae, Toshiaki

268

High Response, Low Level Pulse Engine Thrust Stand System.  

National Technical Information Service (NTIS)

A high response, low level pulse engine thrust stand system has been designed, fabricated, and installed at the Air Force Flight Test Center, Rocket Propulsion Laboratory, Edwards Air Force Base. This system is designed to measure rocket engine thurst in ...

A. J. Couvillion J. D. Smith R. Kuberek

1966-01-01

269

Alteration of Thrust Stand Dynamics Using Hydraulic Force Feedback.  

National Technical Information Service (NTIS)

The report is concerned with the dynamic behavior of a rocket motor and thrust stand combination when restrained by a hydraulic force balance system. The system is analyzed taking into account the nonlinearities caused by limiting flow and fluid compressi...

S. P. Ragsdale

1967-01-01

270

Optimization of Low Thrust Spacecraft Trajectories Using a Genetic Algorithm.  

National Technical Information Service (NTIS)

This thesis concerns the use of genetic algorithms in the optimization of the trajectories of low thrust spacecraft. Genetic algorithms are programming tools which use the principles of biological evolution and adaptation to optimize processes. These algo...

J. C. Eisenreich

1998-01-01

271

Thrust bearing loading arrangement for gas turbine engines  

SciTech Connect

In a gas turbine engine including a stationary wall and a rotor comprising a compressor and a turbine, a thrust bearing loading arrangement is described comprising: means for mounting the rotor for rotating movement. The means including a thrust ball bearing. The engine including at least one sealed cavity between a portion of the rotor and the stationary wall. The cavity including an aft wall and a forward wall, one of the walls having a greater surface area than the other of the walls. The stationary wall having an opening aft of the compressor for providing a path for flow of compressor discharge air into the cavity to increase the load on the thrust bearing. Means are responsive to compressor discharge pressure for controlling flow of compressor discharge air into the cavity to insure unidirectional loading on the thrust bearing throughout the normal operating range of the engine.

Haaser, F.G.

1988-03-15

272

Key Organizational Management and Research Thrusts in Europe.  

National Technical Information Service (NTIS)

A sabbatical at the University of Aston Management Centre, Birmingham, UK and visits to other similar UK and Dutch centers revealed major thrusts in the nature of organizational and management research in Europe. In general, there is considerable research...

J. G. Hunt

1980-01-01

273

Entrainment and Thrust Augmentation in Pulsatile Ejector Flows.  

National Technical Information Service (NTIS)

This study comprised direct thrust measurements, flow visualization by use of a spark shadowgraph technique, and mean and fluctuating velocity measurements with a pitot tube and linearized constant temperature hot-wire anemometry respectively. A gain in t...

V. Sarohia L. Bernal T. Bui

1981-01-01

274

Effect of thrust on the aeroelastic instability of a composite swept wing with two engines in subsonic compressible flow  

NASA Astrophysics Data System (ADS)

This paper aims to investigate aeroelastic stability boundary of subsonic wings under the effect of thrust of two engines. The wing structure is modeled as a tapered composite box-beam. Moreover, an indicial function based model is used to calculate the unsteady lift and moment distribution along the wing span in subsonic compressible flow. The two jet engines mounted on the wing are modeled as concentrated masses and the effect of thrust of each engine is applied as a follower force. Using Hamilton's principle along with Galerkin's method, the governing equations of motion are derived, then the obtained equations are solved in frequency domain using the K-method and the aeroelastic instability conditions are determined. The flutter analysis results of four example wings are compared with the experimental and analytical results in the literature and good agreements are achieved which validate the present model. Furthermore, based on several case studies on a reference wing, some attempts are performed to analyze the effect of thrust on the stability margin of the wing and some conclusions are outlined.

Firouz-Abadi, R. D.; Askarian, A. R.; Zarifian, P.

2013-01-01

275

Inside the Jet Stream  

NSDL National Science Digital Library

The jet stream is a complex phenomenon involving the interplay between many variables. This resource provides a variety of materials, including Giving Rise to the Jet Stream, which is a simplified introduction that shows what generates the jet stream and why it flows from west to east. The site also contains a five-day view of the jet stream, which is a realistic depiction of how the jet stream flows; a page that provides some answers to frequently asked questions about the jet stream; and a glossary of terms used in the Giving Rise to the Jet Stream feature.

Groleau, Rick

276

Thrust Performance of an Ideal Pulse Detonation Engine  

Microsoft Academic Search

Quasi-steady and two-dimensional unsteady formulations of the problem on the operation cycle of a pulse detonation engine are derived. A formula for the specific impulse is obtained, and the thrust performance of the engine is calculated. It is found that the thrust performance of this engine for flight Mach numbers M ? [0; 3.6] and compression ratios p2\\/p1 ? [1;

V. V. Mitrofanov; S. A. Zhdan

2004-01-01

277

Time-dependent changes in failure stress following thrust earthquakes  

Microsoft Academic Search

Two-dimensional (2-D) viscoelastic finite element models were used to calculate the time-dependent changes in Coulomb failure stresses following thrust earthquakes due to respective effects of relaxation of viscous lower crust or upper mantle and postseismic creep on the main fault or its downdip extension. Results suggest that thrust earthquakes cause a coseismic increase in Coulomb stress along antithetic lobes normal

Andrew M. Freed; Jian Lin

1998-01-01

278

Wake mechanics for thrust generation in oscillating foils  

Microsoft Academic Search

Foils oscillating transversely to an oncoming uniform flow produce, under certain conditions, thrust. It is shown through experimental data from flapping foils and data from fish observation that thrust develops through the formation of a reverse von Ka´rma´n street whose preferred Strouhal number is between 0.25 and 0.35, and that optimal foil efficiency is achieved within this Strouhal range.

M. S. Triantafyllou; G. S. Triantafyllou; R. Gopalkrishnan

1991-01-01

279

Generating Thrust with a Biologically-Inspired Robotic Ribbon Fin  

Microsoft Academic Search

Abstract—We present experimental results of thrust produced bya robotic propulsor, the design of which is inspired by the ribbon,fin of the ,South American ,black ghost knifefish (Apteronotus albifrons). This remarkably nimble fish moves by oscillating its ribbon fin rays out of phase and thereby passing a traveling, propulsive wave along the fin’s length. Combinations of thrust from the ribbon fin

Michael Epstein; J. Edward Colgate; Malcolm A. Maciver

2006-01-01

280

Development and Thrust Performance of a Microwave Discharge Hall Thruster  

Microsoft Academic Search

Microwave discharge Hall thrusters have been investigated as a double-stage Hall thruster. Our original microwave discharge Hall thruster, where 2.45-GHz microwaves were employed, needed voluminous waveguides for microwave transmission; therefore direct thrust measurements using a thrust stand were not achieved. Based on the background, by changing wave frequency from 2.45 GHz into 5.8 GHz and developing a new microwave discharge

Hirohisa KUWANO; Akira OHNO; Hitoshi KUNINAKA; Hideki NAKASHIMA

2007-01-01

281

Static thrust recovery of PAR craft on solid surfaces  

Microsoft Academic Search

Power-Augmented-Ram Vehicles belong to a new class of ground-effect machines with hybrid support. Recovered static thrust and static lift on solid surfaces are important amphibious characteristics of this craft. Experimental data for the static thrust recovery and the transition to a hovering mode are obtained in the tests with a vehicle model on two types of ground surface and with

K. I. Matveev

2008-01-01

282

Opposed button thrust surfaces for earth boring bits  

SciTech Connect

An earth boring bit has thrust surfaces with enhanced cooling features. The bit has a body with three depending bearing pins. A cutter having an axial cavity is mounted on each bearing pin. The bearing pin and the cavity have mating thrust shoulders. Hard metal inserts or buttons are spaced around each of the shoulders and secured interferingly in mating holes. The buttons in one of the shoulders protrude slightly from the shoulder to allow air to flow past.

Mullins, J. M.

1985-10-29

283

A double pendulum plasma thrust balance and thrust measurement at a tandem mirror exhaust  

SciTech Connect

For the purpose of measuring the plasma momentum flux in a plasma system, a highly sensitive and precision balance has been developed. It can measure a force, an impulse, or thrust as low as 0.1 mN free of mechanical noise, electrical and magnetic pickups. The double pendulum system consists of two parallel conducting plates. One or both of the plates can be suspended by needles. The needle suspended plate (or plates) can swing freely with negligible friction because of the sharp points of the needles. When one of the plates is impacted by an impulse it will swing relatively to the fixed plate or other movable plate. The capacitance between the plates changes as a result of such a motion. The change of capacitance as a function of time is recorded as an oscillating voltage signal. The amplitude of such a voltage signal is proportional to the impacting force or impulse. The proportional factor can be calibrated. The forces can thus be read out from the recorded value of the voltage. The equation of motion for the pendulum system has been solved analytically. The circuit equation for the electronic measurement system has been formulated and solved numerically. Using this balance the thrust at the exhaust of a Tandem Mirror plasma thruster has been measured. The analytical solution of the overall characteristics agrees greatly with the measurement. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Yang, T.F.; Liu, P.; Chang-Diaz, F.R.; Lander, H.; Childs, R.A.; Becker, H.D.; Fairfax, S.A. [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

1995-09-01

284

Fuel optimum low-thrust elliptic transfer using numerical averaging  

NASA Astrophysics Data System (ADS)

Low-thrust electric propulsion is increasingly being used for spacecraft missions primarily due to its high propellant efficiency. As a result, a simple and fast method for low-thrust trajectory optimization is of great value for preliminary mission planning. However, few low-thrust trajectory tools are appropriate for preliminary mission design studies. The method presented in this paper provides quick and accurate solutions for a wide range of transfers by using numerical orbital averaging to improve solution convergence and include orbital perturbations. Thus, preliminary trajectories can be obtained for transfers which involve many revolutions about the primary body. This method considers minimum fuel transfers using first-order averaging to obtain the fuel optimum rates of change of the equinoctial orbital elements in terms of each other and the Lagrange multipliers. Constraints on thrust and power, as well as minimum periapsis, are implemented and the equations are averaged numerically using a Gausian quadrature. The use of numerical averaging allows for more complex orbital perturbations to be added in the future without great difficulty. The effects of zonal gravity harmonics, solar radiation pressure, and thrust limitations due to shadowing are included in this study. The solution to a transfer which minimizes the square of the thrust magnitude is used as a preliminary guess for the minimum fuel problem, thus allowing for faster convergence to a wider range of problems. Results from this model are shown to provide a reduction in propellant mass required over previous minimum fuel solutions.

Tarzi, Zahi; Speyer, Jason; Wirz, Richard

2013-05-01

285

Characterization of aircraft noise during thrust reverser engagement  

NASA Astrophysics Data System (ADS)

Airport noise impact on communities has been an area of considerable study. However, it has been determined that thrust reverser engagement is an area requiring further research. This paper presents findings on thrust reverser from a noise study done at Washington-Dulles International Airport (IAD) in October of 2004. Previous studies have found that high levels of acoustic energy in commercial aircraft during takeoff are contained below 300 Hz [Sharp, Ben H., Guovich, Yuri A., and Albee, William, W., ``Status of Low-Frequency Aircraft Noise Research and Mitigation,'' Wyle Report WR 01-21, San Francisco, September 2001]. Preliminary analysis of thrust reverser signatures indicates similar findings. A categorization of aircraft noise during thrust reverser engagement is given and looks at factors that may affect the noise characteristics. Some of these factors include: plane type, engine type, and thrust ratings. In addition, a brief analysis of frequency weightings of the Equivalent Sound Level (Leq) and Sound Exposure Level (SEL) metrics, and their application to thrust reverser noise is discussed. [Work supported by the Federal Aviation Administration.

Gutierrez, Remy M.; Atchley, Anthony A.; Hodgdon, Kathleen K.

2005-09-01

286

PALEOMAGNETIC STUDY OF THRUST SHEET ROTATION DURING FORELAND IMPINGEMENT IN THE WYOMING-IDAHO OVERTHRUST BELT  

Microsoft Academic Search

Upper Jurassic and Lower Cretaceous strata in the Darby and Absaroka thrust sheets were sampled in order to paleomagnetically evaluate thrust sheet rotation in the Wyoming-Idaho overthrust belt. No significant rotations were found. Lack of rotation in these thrust sheets suggests that previously reported rotation of the Prospect thrust sheet was not transmit- ted to the older Darby and Absaroka

Susan Y. Schwartz; Rob Van der Voo

1984-01-01

287

Oscillatory and sector-zoned garnets record cyclic (?) rapid thrusting in central Nepal  

Microsoft Academic Search

Garnets with oscillatory zoning (repeated compositional reversals) and sector zoning (crystallographically controlled compositional differences) were discovered in rocks from near the Main Central Thrust in the Langtang region, central Nepal. This zoning results from crystal growth kinetic effects related to extraordinarily rapid, possibly cyclic thrusting. If cyclic thrusting occurred, then timescales of thrust rate inhomogeneities are ?25 Kyr, implying that

Matthew J. Kohn

2004-01-01

288

Deformation of brittle-ductile thrust wedges in experiments and nature  

Microsoft Academic Search

Even though the rheology of thrust wedges is mostly frictional, a basal ductile decollement is often involved. By comparison with purely frictional wedges, such brittle-ductile wedges generally display anomalous structures such as backward vergence, widely spaced thrust units, and nonfrontward sequences of thrust development. Laboratory experiments are used here to study the deformation of brittle-ductile thrust wedges. Results are compared

J. H. W. Smit; J. P. Brun; D. Sokoutis

2003-01-01

289

Navigational Vectors  

NSDL National Science Digital Library

This is a high school instructional unit that features nine lessons relating to vectors. Students build understanding of vector properties as they learn airplane navigation. Problem-based learning activities include reading real-time weather maps, tracking airplanes flying in U.S. skies, calculating vector components, analyzing effects of wind velocity, and completing training segments similar to a private pilot certification program. Participants have access to help from experts at the Polaris Career Center. Comprehensive teacher guides, student guides, reference materials, and assessments are included. This resource was developed by the Center for Innovation in Science and Engineering Education (CIESE). Participation is cost-free; additional options are available for registered users.

290

Numerical investigation of the thrust efficiency of a laser propelled vehicle  

SciTech Connect

This thesis is about the gasdynamics of laser propulsion, and studies the expansion efficiency of the blast wave generated when the propellant is superheated by laser. The flow situation for a thruster propelled by ablated gas which is energized by a laser pulse is numerically simulated. The flow is axisymmetric and nonsteady, and is assumed to be inviscid due to its high Reynolds number. The high pressure expansion of the laser heated gas generates thrust as it pushes against the vehicle. Gas expansion lateral to the thrust vector causes performance to decrease. The vehicle geometry and the laser pulse characteristics determine the degree to which the flow is one dimensional. As the thruster's parameters are varied, its impulse is calculated and compared to the limiting impulse of a one-dimensional system, and thus the thrust efficiency is computed. Lateral expansion losses computed by simulating the flow of the expanding gas time-accurately on a computer are far less than losses predicted using the method of characteristics, which is the best alternate means of computation. Flows which exhibit a substantial amount of lateral expansion can still yield an expression efficiency which exceeds 70%. Steger and Warming's flux split numerics for the Euler equations are modified for blast simulations into near vacuum ambient conditions. The majority of the calculations performed assume an ideal gas equation of state with {gamma} = 1.2. The propellant Lithium Hydride has shown excellent promise in the laboratory, yielding I{sub sp} = 800 --1000 sec. Equilibrium and kinetic modeling of LiH is undertaken. These additional mechanisms are then incorporated into the efficiency calculations. 32 refs., 54 figs., 16 tabs.

Mulroy, J.R. (Stanford Univ., CA (United States))

1990-08-01

291

Vector carpets  

SciTech Connect

Previous papers have described a general method for visualizing vector fields that involves drawing many small ``glyphs`` to represent the field. This paper shows how to improve the speed of the algorithm by utilizing hardware support for line drawing and extends the technique from regular to unstructured grids. The new approach can be used to visualize vector fields at arbitrary surfaces within regular and unstructured grids. Applications of the algorithm include interactive visualization of transient electromagnetic fields and visualization of velocity fields in fluid flow problems.

Dovey, D.

1995-03-22

292

Vector Calculus  

NSDL National Science Digital Library

This is a series of lectures, authored by Chris Tisdell of the University of New South Wales, for MATH2111 "Higher Several Variable Calculus" and "Vector Calculus", which is a 2nd-year mathematics subject taught at UNSW, Sydney. This playlist provides a shapshot of some lectures presented in Session 1, 2009. These lectures focus on presenting vector calculus in an applied and engineering context, while maintaining mathematical rigour. Thus, this playlist may be useful to students of mathematics, but also to those of engineering, physics and the applied sciences. There is an emphasis on examples and also on proofs.

Tisdell, Chris

2010-12-16

293

Bilateral and multiple cavitation sounds during upper cervical thrust manipulation  

PubMed Central

Background The popping produced during high-velocity, low-amplitude (HVLA) thrust manipulation is a common sound; however to our knowledge, no study has previously investigated the location of cavitation sounds during manipulation of the upper cervical spine. The primary purpose was to determine which side of the spine cavitates during C1-2 rotatory HVLA thrust manipulation. Secondary aims were to calculate the average number of pops, the duration of upper cervical thrust manipulation, and the duration of a single cavitation. Methods Nineteen asymptomatic participants received two upper cervical thrust manipulations targeting the right and left C1-2 articulation, respectively. Skin mounted microphones were secured bilaterally over the transverse process of C1, and sound wave signals were recorded. Identification of the side, duration, and number of popping sounds were determined by simultaneous analysis of spectrograms with audio feedback using custom software developed in Matlab. Results Bilateral popping sounds were detected in 34 (91.9%) of 37 manipulations while unilateral popping sounds were detected in just 3 (8.1%) manipulations; that is, cavitation was significantly (P < 0.001) more likely to occur bilaterally than unilaterally. Of the 132 total cavitations, 72 occurred ipsilateral and 60 occurred contralateral to the targeted C1-2 articulation. In other words, cavitation was no more likely to occur on the ipsilateral than the contralateral side (P = 0.294). The mean number of pops per C1-2 rotatory HVLA thrust manipulation was 3.57 (95% CI: 3.19, 3.94) and the mean number of pops per subject following both right and left C1-2 thrust manipulations was 6.95 (95% CI: 6.11, 7.79). The mean duration of a single audible pop was 5.66?ms (95% CI: 5.36, 5.96) and the mean duration of a single manipulation was 96.95?ms (95% CI: 57.20, 136.71). Conclusions Cavitation was significantly more likely to occur bilaterally than unilaterally during upper cervical HVLA thrust manipulation. Most subjects produced 3–4 pops during a single rotatory HVLA thrust manipulation targeting the right or left C1-2 articulation; therefore, practitioners of spinal manipulative therapy should expect multiple popping sounds when performing upper cervical thrust manipulation to the atlanto-axial joint. Furthermore, the traditional manual therapy approach of targeting a single ipsilateral or contralateral facet joint in the upper cervical spine may not be realistic.

2013-01-01

294

Development of the Himalayan frontal thrust zone: Salt Range, Pakistan  

SciTech Connect

The Salt Range is the active frontal thrust zone of the Himalaya in Pakistan. Seismic reflection data show that a 1 km offset of the basement acted as a buttress that caused the central Salt Range-Potwar Plateau thrust sheet to ramp to the surface, exposing Mesozoic and Paleozoic strata. The frontal part of the thrust sheet was folded passively as it overrode the subthrust surface on a ductile layer of Eocambrian salt. Lack of internal deformation of the rear part of the thrust sheet is due to decoupling of sediments from the basement along this salt layer. Early to middle Pliocene (approx. 4.5 Ma) conglomerate deposition in the southern Potwar Plateau, previously interpreted in terms of compressional deformation, may instead document uplift related to basement normal faulting. Stratigraphic evidence, paleomagnetic dating of unconformities, and sediment-accumulation rates suggest that the thrust sheet began to override the basement offset from 2.1 to 1.6 Ma. Cross-section balancing demonstrates at least 20 to 23 km of shortening across the ramp. The rate of Himalayan convergence that can be attributed to underthrusting of Indian basement beneath sediments in the Pakistan foreland is therefore at least 9-14 mm/yr, about 20-35% of the total plate convergence rate.

Baker, D.M.; Lillie, R.J.; Yeats, R.S.; Johnson, G.D.; Yousuf, M.; Zamin, A.S.H.

1988-01-01

295

Three-dimensional geometry and kinematics of the Gale-Buckeye thrust system, ouachita fold and thrust belt, Latimer and Pittsburg counties, Oklahoma  

SciTech Connect

The Gale-Buckeye thrust system consists of a series of blind thrusts and folds near the boundary between the Ouachita fold and thrust belt and the Arkoma basin in Oklahoma. A dense grid of high-resolution seismic reflection data, augumented by data from exploration and production wells, provides an opportunity to analyze the three-dimensional geometry and kinematics of these structures in detail. We recognized two previously unmapped transverse structures in the Gale-Buckeye thrust system: a sharp, left-stepping zone of oblique ramps and a tear fault within the Gale thrust sheet. These transverse structures are spatially coincident with similar structural trends in lower Paleozoic strata beneath the thrust system as well as outcropping structural trends on the surface. This interpretation extends thrust in the Gale-Buckeye system to minimum strike lengths of 7-9 mi (11- 15 km) and fault length-to-displacement ratios of about 10:1. Interpreted structural relationships suggest that the Gale and Buckeye thrusts formed in a backward-stepping manner. Measurement of differential transport angles from our interpretations of the Gale-Buckeye thrust system indicates that along-strike displacement variations of the Gale and Buckeye thrusts are consistent with thrusts from other nonmetamorphic fold and thrust belts. Using the differential transport model, we infer that the tear fault in the Gale thrust sheet indicates a region that became segmented to accommodate excessive along-strike differences in displacement. In addition, we use the model to explain errors in previous interpretations of the Gale-Buckeye thrust system that resulted in the drilling of dry holes. Integrating realistic differential transport angles with our interpretations for extent, style and sequence of thrusting provides new strategies for hydrocarbon exploration throughout the region. 43 refs., 17 figs., 4 tabs.

Wilkerson, M.S. (Univ. of Illinois, Urbana (United States) Exxon Production Research, Houston, TX (United States)); Wellman, P.C. (Exxon Exploration Company, Houston, TX (United States))

1993-06-01

296

Kink bands in thrust regime: Examples from Srinagar-Garhwal area, Uttarakhand, India  

NASA Astrophysics Data System (ADS)

This paper deciphers the late stress systems involved in the development of kink bands in the perspective of thrust regime. In kink bands, the correlation coefficient for ?- ? plots is positive near thrusts and negative away from thrusts. The plots show nearly linear relationship near thrusts and non-linear relationship away from thrusts. The rotation was prominent mechanism of kink band formation near thrusts and rotation coupled with shearing, along the kink planes away from thrusts. Along thrusts ? 1 is horizontal E-W trend and it rotates to horizontal N-S trend away from the thrust. The proposed model establishes that (1) the shearing along kink planes led to angular relationship, ? < ? and (2) the kink planes of conjugate kinks could be used for paleostress analysis even in those cases where shearing along these planes has occurred.

Shekhar, Shashank; Bhola, M.; Saklani, S.

2011-10-01

297

SYNCHROTRON RADIATION OF SELF-COLLIMATING RELATIVISTIC MAGNETOHYDRODYNAMIC JETS  

SciTech Connect

The goal of this paper is to derive signatures of synchrotron radiation from state-of-the-art simulation models of collimating relativistic magnetohydrodynamic (MHD) jets featuring a large-scale helical magnetic field. We perform axisymmetric special relativistic MHD simulations of the jet acceleration region using the PLUTO code. The computational domain extends from the slow-magnetosonic launching surface of the disk up to 6000{sup 2} Schwarzschild radii allowing jets to reach highly relativistic Lorentz factors. The Poynting-dominated disk wind develops into a jet with Lorentz factors of {Gamma} {approx_equal} 8 and is collimated to 1{sup 0}. In addition to the disk jet, we evolve a thermally driven spine jet emanating from a hypothetical black hole corona. Solving the linearly polarized synchrotron radiation transport within the jet, we derive very long baseline interferometry radio and (sub-) millimeter diagnostics such as core shift, polarization structure, intensity maps, spectra, and Faraday rotation measure (RM) directly from the Stokes parameters. We also investigate depolarization and the detectability of a {lambda}{sup 2}-law RM depending on beam resolution and observing frequency. We find non-monotonic intrinsic RM profiles that could be detected at a resolution of 100 Schwarzschild radii. In our collimating jet geometry, the strict bimodality in the polarization direction (as predicted by Pariev et al.) can be circumvented. Due to relativistic aberration, asymmetries in the polarization vectors across the jet can hint at the spin direction of the central engine.

Porth, Oliver; Fendt, Christian; Vaidya, Bhargav [Max Planck Institute for Astronomy, Koenigstuhl 17, 69117 Heidelberg (Germany); Meliani, Zakaria, E-mail: porth@mpia.de, E-mail: fendt@mpia.de [Centre for Plasma Astrophysics, K. U. Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium)

2011-08-10

298

Jet physics in ALICE  

Microsoft Academic Search

This work aims at the performance of the ALICE detector for the measurement of high-energy jets at mid-pseudo-rapidity in ultra-relativistic nucleus--nucleus collisions at LHC and their potential for the characterization of the partonic matter created in these collisions. In our approach, jets at high energy with E_{T}>50 GeV are reconstructed with a cone jet finder, as typically done for jet

Constantinos A. Loizides; Johann Wolfgang von Goethe

2005-01-01

299

Jet Noise: Since 1952  

Microsoft Academic Search

:   Jet noise research was initiated by Sir James Lighthill in 1952. Since that time, the development of jet noise theory has\\u000a followed a very tortuous path. This is, perhaps, not surprising for the understanding of jet noise is inherently tied to the\\u000a understanding of turbulence in jet flows. Even now, our understanding of turbulence is still tenuous. In the

Christopher K. W. Tam

1998-01-01

300

Miniconference on astrophysical jets  

SciTech Connect

This miniconference brought together observers of astrophysical jets, analytic and numerical modelers of both astrophysical jets and spheromaks, and laboratory experimentalists. The purpose of the miniconference was to encourage interaction between these diverse groups and also expose the plasma physics community to the interesting plasma issues associated with astrophysical jets. The miniconference emphasized magnetically driven astrophysical jets and consisted of three half-day sessions. The order of presentation was approximately: observations and general properties, experiments, numerical models, and special topics.

Bellan, P.M. [Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States)

2005-05-15

301

Quasar Jet Acceleration  

Microsoft Academic Search

We observed radio jets in six lobe-dominated quasars (LDQs) from 1995 to 2008 using the NRAO VLBA at 8.4 and 15 GHz. These observations have tracked jet component positions and velocities over that time period. There is a correlation between apparent jet speed and projected core distance in these LDQs at greater than 99 per cent confidence levels (Hough 2008,

Nicholas Polito; David Hough

2009-01-01

302

Radial loads and axial thrusts on centrifugal pumps  

SciTech Connect

The proceedings of a seminar organised by the Power Industries Division of the IMechE are presented in this text. Complete contents: Review of parameters influencing hydraulic forces on centrifugal impellers; The effect of fluid forces at various operation conditions on the vibrations of vertical turbine pumps; A review of the pump rotor axial equilibrium problem - some case studies; Dynamic hydraulic loading on a centrifugal pump impeller; Experimental research on axial thrust loads of double suction centrifugal pumps; A comparison of pressure distribution and radial loads on centrifugal pumps; A theoretical and experimental investigation of axial thrusts within a multi-stage centrifugal pump.

Not Available

1986-01-01

303

Extending acoustic data measured with small-scale supersonic model jets to practical aircraft exhaust jets  

NASA Astrophysics Data System (ADS)

Modern military aircraft jet engines are designed with variable geometry nozzles to provide optimum thrust in different operating conditions within the flight envelope. However, the acoustic measurements for such nozzles are scarce, due to the cost involved in making full-scale measurements and the lack of details about the exact geometry of these nozzles. Thus the present effort at The Pennsylvania State University and the NASA Glenn Research Center, in partnership with GE Aviation, is aiming to study and characterize the acoustic field produced by supersonic jets issuing from converging-diverging military style nozzles. An equally important objective is to develop a scaling methodology for using data obtained from small- and moderate-scale experiments which exhibits the independence of the jet sizes to the measured noise levels. The experimental results presented in this thesis have shown reasonable agreement between small-scale and moderate-scale jet acoustic data, as well as between heated jets and heat-simulated ones. As the scaling methodology is validated, it will be extended to using acoustic data measured with small-scale supersonic model jets to the prediction of the most important components of full-scale engine noise. When comparing the measured acoustic spectra with a microphone array set at different radial locations, the characteristics of the jet noise source distribution may induce subtle inaccuracies, depending on the conditions of jet operation. A close look is taken at the details of the noise generation region in order to better understand the mismatch between spectra measured at various acoustic field radial locations. A processing methodology was developed to correct the effect of the noise source distribution and efficiently compare near-field and far-field spectra with unprecedented accuracy. This technique then demonstrates that the measured noise levels in the physically restricted space of an anechoic chamber can be appropriately extrapolated to represent the expected noise levels at different noise monitoring locations of practical interest. With the emergence of more powerful fighter aircraft, supersonic jet noise reduction devices are being intensely researched. Small-scale measurements are a crucial step in evaluating the potential of noise reduction concepts at an early stage in the design process. With this in mind, the present thesis provides an acoustic assessment methodology for small-scale military-style nozzles with chevrons. Comparisons are made between the present measurements and those made by NASA at moderate-scale. The effect of chevrons on supersonic jets was investigated, highlighting the crucial role of the jet operating conditions on the effects of chevrons on the jet flow and the subsequent acoustic benefits. A small-scale heat simulated jet is investigated in the over-expanded condition and shows no substantial noise reduction from the chevrons. This is contrary to moderate-scale measurements. The discrepancy is attributed to a Reynolds number low enough to sustain an annular laminar boundary layer in the nozzle that separates in the over-expanded flow condition. These results are important in assessing the limitations of small-scale measurements in this particular jet noise reduction method. Lastly, to successfully present the results from the acoustic measurements of small-scale jets with high quality, a newly developed PSU free-field response was empirically derived to match the specific orientation and grid cap geometry of the microphones. Application to measured data gives encouraging results validating the capability of the method to produce superior accuracy in measurements even at the highest response frequencies of the microphones.

Kuo, Ching-Wen

304

EVIDENCE FOR HIGHLY RELATIVISTIC VELOCITIES IN THE KILOPARSEC-SCALE JET OF THE QUASAR 3C 345  

SciTech Connect

In this paper we use radio polarimetric observations of the jet of the nearby bright quasar 3C 345 to estimate the fluid velocity on kiloparsec scales. The jet is highly polarized, and surprisingly, the electric vector position angles in the jet are 'twisted' with respect to the jet axis. Simple models of magnetized jets are investigated in order to study various possible origins of the electric vector distribution. In a cylindrically symmetric transparent jet a helical magnetic field will appear either transverse or longitudinal due to partial cancellations of Stokes parameters between the front and back of the jet. Synchrotron opacity can break the symmetry, but it leads to fractional polarization less than that observed and to strong frequency dependence that is not seen. Modeling shows that differential Doppler boosting in a diverging jet can break the symmetry, allowing a helical magnetic field to produce a twisted electric vector pattern. Constraints on the jet inclination, magnetic field properties, intrinsic opening angle, and fluid velocities are obtained and show that highly relativistic speeds ({beta} {approx}> 0.95) are required. This is consistent with the observed jet opening angle, with the absence of a counter-jet, with the polarization of the knots at the end of the jet, and with some inverse-Compton models for the X-ray emission from the 3C 345 jet. This model can also apply on parsec scales and may help explain those sources where the electric vector position angles in the jet are neither parallel nor transverse to the jet axis.

Roberts, David H.; Wardle, John F. C., E-mail: roberts@brandeis.edu [Department of Physics MS-057, Brandeis University, Waltham, MA 02454-0911 (United States)

2012-11-10

305

Summary of Fluidic Thrust Vectoring Research Conducted at NASA Langley Research Center.  

National Technical Information Service (NTIS)

Interest in low-observable aircraft and in lowering an aircraft's exhaust system weight sparked decades of research for fixed geometry exhaust nozzles. The desire for such integrated exhaust nozzles was the catalyst for new fluidic control techniques; inc...

K. A. Deere

2003-01-01

306

Measurements of $W/Z$ Production in Association with Jets at D0  

SciTech Connect

Understanding the associated production of jets and vector bosons is of paramount importance for the top quark physics, for the Higgs boson and for many new physics searches. In this contribution, recent measurements of W/Z+jets and Z+b-jets processes by the D0 experiment are presented. The measurements are compared to theoretical predictions from next-to-leading order (NLO) perturbative QCD calculations where available, and to several Monte Carlo model predictions.

Kumar, Ashish; /SUNY, Buffalo

2011-10-01

307

Extragalactic Jets: Some Unanswered Questions and the Prospects for GLAST  

NASA Astrophysics Data System (ADS)

An introduction to AGN jets is presented, paying particular attention to general questions that are currently being addressed or are likely to be addressed using imminent observational capabilities in the gamma ray and radio bands. It is argued that it should become possible to locate the sites of radio and gamma ray emission and to define the jet kinematical structure in a far more prescriptive fashion. Astrophysical arguments should then suffice to affirm (or refute) the common presumptions that synchrotron and inverse Compton emission dominate other processes and that the working substance changes from electromagnetic field to a pair plasma to an ionic plasma as the jet propagates away from the central black hole. Our understanding of jet dynamics can also improve through better characterization of the properties of the surrounding medium which should help decide if magnetic pinching is important and lead to more accurate measurements of jet powers, thrusts, discharges and currents. Combining jet and disk observations should test a ``Central Dogma'', namely that intrinsic AGN behavior is mainly dictated by the mass supply rate in units of the Eddington rate and the spin of the hole in units of its maximum allowed value, with the overall scale of power, variation etc determined by the hole mass. The connection between observed jet properties and the physical processes occurring around black holes is likely to remain conjectural for a while, though relevant numerical simulations are improving rapidly. Finally, the environmental impact of jets should become much clearer along with the role of AGN in the co-evolution of their host galaxies.

Blandford, R.

2008-06-01

308

The interaction between deepwater channel systems and growing thrusts and folds, toe-thrust region of the deepwater Niger Delta  

NASA Astrophysics Data System (ADS)

Gravity-driven seaward-verging thrusts, landward-verging back-thrusts and associated folds often characterize the slope and deepwater settings of passive margins. These structures, found in the "toe-thrust" region of the system, exert a significant control on sediment gravity flows because they create and determine the location and configuration of sediment depocentres and transport systems. However, to fully understand the interaction between sediment gravity flows and seabed topography we need to evaluate and quantify the geomorphic response of sub-marine channels to faulting in an area where the degree of tectonic shortening can be well constrained. This study exploits 3D seismic data in the outer toe-thrust region of the deepwater Niger Delta to analyze the interaction between Plio-Pleistocene channel systems and actively growing folds and thrusts. We first mapped folds and thrusts from the seismic data and we used this data to reconstruct the history of fold growth. We then used the sea-bed seismic horizon to build a 50 m resolution Digital Elevation Model (DEM) of the sea floor in Arc-GIS. From the DEM, we extracted channel long profiles across growing structures for both the current channel thalwegs and for the associated channel cut-and-fill sequences identified from the seismic data. We measured channel geometry at regular intervals along the channel length to evaluate system response to tectonic perturbation, and we used this data to help us approximate the down-system distribution of bed shear stress, and hence incision capacity. Initial results show that changes in submarine channel longitudinal profiles are directly correlated to underlying seabed thrusts and folds. Channels gradients are typically linear to slightly concave, and have an average gradient of 0.90. Actively growing thrusts are associated with a local steepening in channel gradient (up to 200% change), which typically extends 0.5 to 2 km upstream of the fault. Within these "knickzones", channel incision increases by approximately 50%, with a corresponding width decrease of approximately 25% or less. Our data demonstrate that submarine channel systems dynamically adjust their geometry and basal gradient in order to keep pace with the growth of tectonic structures and our results provide new data to test models of turbidite incision.

Jolly, B.; Lonergan, L.; Whittaker, A.

2012-04-01

309

Hydroacoustic pulsating jet generator  

NASA Astrophysics Data System (ADS)

A high pressure turbulent jet generator connected to a low pressure hydraulic tube is studied to investigate water hammer in tubes with fast flow variations, generating high pressure pulsating water jets. The pulsating jet generator consists of a tube, a hydraulic valve, a spring, and a water container. The jet is the effect of the combination of turbulent pipe flow with a valve for flow nozzle. The jet pressure depends on specific oscillation impedance and flow velocity variations. For inlet pressure of 0.5 to 2 bar the pressure rises to 40 bar. The described pulsating jet generator is more effective than the earlier model. A piezoelectric pressure controller is used to register pressure signals and high speed photos are made of the jet. Test results are consistent with theoretical calculation.

Unrau, A.; Meier, G. E. A.

1987-04-01

310

Numerical simulation of thrust reverser for rear mounted engine  

Microsoft Academic Search

The objectives of the study were to establish the feasibility of the evaluation of the performances of thrust reverser systems through numerical simulations, with Onera's Cedre computation code. Two configurations were retained, the first one was an isolated engine and the second one was an installed engine in a rear mounted generic configuration. The first configuration concerns the aft part

G. TURPIN; F. VUILLOT; C. CROISY; D. BERNIER

311

10. DETAIL SHOWING THRUST MEASURING SYSTEM. Looking up from the ...  

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

10. DETAIL SHOWING THRUST MEASURING SYSTEM. Looking up from the test stand deck to east. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

312

REAR DETAIL OF RIGHT ENGINE AND WING. THRUST REVERSER REMAINS ...  

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

REAR DETAIL OF RIGHT ENGINE AND WING. THRUST REVERSER REMAINS OPEN. MECHANICS JONI BAINE (R) AND BILL THEODORE(L) OPEN FLAP CARRIAGE ACCESS WITH AN IMPACT GUN. THEY WILL CHECK TRANSMISSION FLUID AND OIL THE JACK SCREW. AT FAR LEFT UTILITY MECHANICS BEGIN BODY POLISHING. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

313

Operant control of pathological tongue thrust in spastic cerebral palsy.  

PubMed Central

Pathological tongue thrust (reverse swallowing) has been associated with neuromuscular disorders and linked to dental malocclusion, articulation problems, difficulty in eating, and excessive drooling. In this study, observable tongue thrust in a 10-year-old retarded male was modified during mealtime using a procedure consisting of differential reinforcement (presentation of food contingent upon tongue in) and punishment (gently pushing the tongue back into the mouth with a spoon). Results of a reversal design showed substantial decreases in tongue thrust and food expulsion, and a large increase in observed chewing. These data compared favorably with data obtained for other retarded persons not judged to be tongue thrusters; in addition, the objective results of the treatment program were substantiated via pre-post evaluations done by occupational and physical therapists. These findings suggest that operant techniques may be an effective means of treating tongue thrust and its associated problems, and that further development and evaluation of behavioral interventions may provide a desirable alternative to more intrusive surgical or mechanical procedures.

Thompson, G A; Iwata, B A; Poynter, H

1979-01-01

314

Treatment of Tongue Thrust with Hypnosis: Two Case Histories  

Microsoft Academic Search

Tongue thrust is a relatively infrequent habit which can result in disruptive, permanent oral malocclusion, bone changes, and facial disharmony. The use of hypnotic phenomena can augment myofunctional therapy. Temperature control, glove anesthesia, relaxation, and imagery enhance demonstration of the proper way to swallow. The cornerstone of having the patient actually feel the contraction at the insertion of the masseter

Harold P. Golan

1991-01-01

315

Optimization of Low Thrust Trajectories With Terminal Aerocapture.  

National Technical Information Service (NTIS)

This thesis explores using a direct pseudospectral method for the solution of optical control problems with mixed dynamics. An easy to use MATLAB optimization package known as DIDO is used to obtain the solutions. The modeling of both low thrust interplan...

S. B. Josselyn

2003-01-01

316

DIRECT CONVERSION OF NUCLEAR ENERGY INTO ELECTRICAL OR THRUST ENERGY  

Microsoft Academic Search

Direct conversion of nuclear energy into electrical energy or thrust ; involves the confinement of a plasma at temperatures of the order of 10⁸ ; deg K and higher, which excludes physical walls. Two concepts through which this ; may be done are introduced. In both cases spherical waves propagate radially ; inward. In the first, the amplitude is the

Fuechsel

1962-01-01

317

Measurements of Compressibility Effects in Stepped Thrust Gas Film Bearings  

Microsoft Academic Search

Hydrodynamic gas film bearings are used for supporting high-speed, lightly loaded rotating machinery. Stepped-type gas film bearings are often used for such machinery because of theïr simple structure, high stability and load carrying capacity. This paper describes the measurements of compressibility effects on the static and dynamic characteristics of stepped thrust gas film bearings. In the experiments, the minimum film

H. Hashimoto; M. Ochiai

1999-01-01

318

STUDY OF A GAS THRUST BEARING WITH SUPPLY GROOVES  

Microsoft Academic Search

Plane externally pressurized thrust gas bearings for high speed spindles are considered. The behavior of the rotor-bearing system is studied both numerically and experimentally. A numerical model based on Reynolds equation is used to simulate the static and dynamic behavior of the system. Flow rate equation through inlet orifices is coupled with Reynolds equation. The flow rate is calculated by

Guido BELFORTE; Federico COLOMBO; Terenziano RAPARELLI; Andrea TRIVELLA; Vladimir VIKTOROV

2008-01-01

319

Thrust Ripples Suppression of Permanent Magnet Linear Synchronous Motor  

Microsoft Academic Search

The thrust ripples in permanent magnet linear synchronous motor (PMLSM) are mainly generated by the distortion of the stator flux linkage distribution, reluctance force due to the relative position between the mover and stator, cogging force caused by the interaction between the permanent magnet (PM) and the iron core, and the end effects. This is the significant drawback which will

Yu-Wu Zhu; Yun-Hyun Cho

2007-01-01

320

Design of Force Sensor Leg for a Rocket Thrust Detector  

Microsoft Academic Search

A hybrid rocket is composed of a solid fuel and a separate liquid or gaseous oxidizer. These rockets may be throttled like liquid rockets, are safer than solid rockets, and are much less complex than liquid rockets. However, hybrid rockets produce thrust oscillations that are not practical for large scale use. A lab scale hybrid rocket at the University of

Douglas Woten; Tripp McGehee; Anne Wright

2005-01-01

321

Minimum Propellant Low-Thrust Maneuvers near the Libration Points  

Microsoft Academic Search

The impulse technique certainly can bring the vehicle on orbits around the libration points or close to them. The question that aries is, by what means can the vehicle arrive in such cases at the libration points? A first investigation carried out in this paper can give an answer: the use of the technique of low-thrust, which, in addition, can

A. Marinescu; M. Dumitrache

2002-01-01

322

Passive Thrust Oscillation Mitigation for the CEV Crew Pallet System.  

National Technical Information Service (NTIS)

The Crew Exploration Vehicle (CEV) was intended to be the next-generation human spacecraft for the Constellation Program. The CEV Isolator Strut mechanism was designed to mitigate loads imparted to the CEV crew caused by the Thrust Oscillation (TO) phenom...

C. Powell J. Pellicciotti K. Johnson M. Sammons R. Buehrle

2012-01-01

323

A new NSF thrust: computer impact on society  

Microsoft Academic Search

The recently formed (Nov. 9, 1972) Computer Impact on Society Section in NSF's Office of Computing Activities reflected a growing need to understand the wide and deep impact which computers and associated information technology are having on our social organizations and way of life. The program has two principal thrusts, computer impact on organizations and computer impact on the individual,

Peter Lykos

1973-01-01

324

Digital field trip to the Central Nevada Thrust Belt  

SciTech Connect

Hydrocarbon exploration in the Central Nevada Thrust Belt is still in its infancy. However, this thrust belt contains all the elements necessary for hydrocarbon accumulations: thick, organically-rich shales; reefs, regional unconformities, karst surfaces, porous sandstones, and extensive and pervasive fractures; anticlines tens of miles long by miles wide; thrust faults that juxtapose potential source and reservoir rocks; and oil seeps. Along a fairway from Las Vegas to Elko, for example, thick Mississippian shales contain 4-6% total organic carbon and are oil-prone and thermally mature. This presentation from a laptop computer and LCD projector is a multimedia version of our October 12-14, 1995 field trip to document the hydrocarbon potential of the thrust belt in Clark, Lincoln, and Nye Counties. Outcrop images were recorded by a digital camera that has a resolution equivalent to a 14 inch computer screen; these images were then downloaded to the computer. All of the images were processed digitally on location to enhance picture quality and color contrast. Many were annotated on location with our observations, measurements, and interpretations. These field annotations are supplemented in this presentation by laboratory analyses. The presentation includes full-color, annotated outcrop images, sounds, and animations. The results show the viability of the new, inexpensive digital cameras to geologic field work in which a multimedia report, ready for presentation to management, can be generated in the field.

Chamberlain, A.K. (Cedar Strat Corp., Hiko, NV (United States)); Hook, S.C. (Texaco E P Technology Department, Houston, TX (United States)); Frost, K.R. (Texaco Exploration and Production, Inc., Houston, TX (United States))

1996-01-01

325

Repeated Palaeozoic thrusting and allochthoneity of Precambrian basement, northern Tasmania  

Microsoft Academic Search

Stratigraphic and structural relationships in northern Tasmania suggest a deformation sequence involving west?directed Cambrian and Devonian thrusting with imbrication of Precambrian basement, the Cambrian oceanic suite and the Ordovician continental margin overlap sequences. Section balancing requires a depth to detachment of 5–10 km and a total shortening on the order of 80 km, with at least half of this displacement

N. B. Woodward; D. R. Gray; C. G. Elliott

1993-01-01

326

Closed form low-thrust trajectories for Mars missions  

SciTech Connect

Several closed form trajectory solutions have been developed for low-thrust interplanetary flight and used with patched conics for analysis of combined propulsion systems. The solutions provide insight into alternative types of Mars missions, and show considerable mass savings for fast crewed missions with outbound trip times on the order of 90--100 days. 7 refs.

Purvis, J.W.

1992-01-01

327

Closed form low-thrust trajectories for Mars missions  

SciTech Connect

Several closed form trajectory solutions have been developed for low-thrust interplanetary flight and used with patched conics for analysis of combined propulsion systems. The solutions provide insight into alternative types of Mars missions, and show considerable mass savings for fast crewed missions with outbound trip times on the order of 90--100 days. 7 refs.

Purvis, J.W.

1992-08-01

328

Experimental Investigation of a Circular Thrust Augmenting Ejector.  

National Technical Information Service (NTIS)

A 4.4 in diameter circular ejector was tested to determine the effect on thrust augmentation ratio of the primary nozzle height and injection angle. Also tested were the effects of alternating primary nozzle injection angles, diffuser blowing and suction,...

G. C. Uhuad

1985-01-01

329

Aerodynamic Integration of Thrust Reversers on the Fokker 100.  

National Technical Information Service (NTIS)

The Fokker 100 is a twin engined T-tailed aircraft developed as a short to medium haul passenger and cargo transport. The engines are located on the aft fuselage. The development of thrust reversers on this type of aircraft was accomplished through differ...

J. Vanhengst

1992-01-01

330

Modal Response of Free Rockets under Thrust Loading.  

National Technical Information Service (NTIS)

In the report an analysis yielding the modal responses of a rocket, constrained or in free flight, is presented. The effects of a tangential end thrust are considered as are the influences of shear and structural joints. The modelling was accomplished by ...

H. B. Wilson J. J. Richardson

1974-01-01

331

The Effect of Atmospheric Pressure on Rocket Thrust -- Part I.  

ERIC Educational Resources Information Center

|The first of a two-part question asks: Does the total thrust of a rocket depend on the surrounding pressure? The answer to this question is provided, with accompanying diagrams of rockets. The second part of the question (and answer) are provided in v20 n7, p479, Oct 1982 of this journal. (Author/JN)|

Leitner, Alfred

1982-01-01

332

Axial Thrust Balancing of the LE-7 LOX Turbopump.  

National Technical Information Service (NTIS)

A self-balancing type axial-thrust balancing system referred to as balance piston was applied to the LE-7 LOX turbopump, the discharge pressure of which exceeds 30 MPa. A research model of the turbopump showed that pressure distribution in the balancing c...

S. Hasegawa T. Shimura

1993-01-01

333

Stress waves in an elastic rocket subjected to thrust loading  

Microsoft Academic Search

Stress wave pattern in an elastic rocket due to a sudden axial thrust loading is investigated. The rocket structure is assumed to be a nonhomogeneous elastic bar, and finite element method is employed in the investigation by averaging the elemental properties of each element. Dynamic deflections and stresses are determined and the corresponding wave patterns are discussed.

J. R. Banerjee; K. Ramadasa; B. Ramabhat

1977-01-01

334

Internal deformation of thrust sheets, Sawtooth Range, northwest Montana  

SciTech Connect

A popular conception in the geological community is that sedimentary rocks of the Cordilleran foreland fold-and-thrust belt are unmetamorphosed and lack significant internal deformation. This idea has been incorporated by many workers into regionally balanced cross sections and palinspastic restorations that yield approximately 50% shortening. This amount of shortening is based entirely on plane strain, rigid body translations, and rotations of strata above a regional decollement that becomes structurally and stratigraphically deeper to the west. Detailed field studies in the Sawtooth Range (Disturbed belt) of northwestern Montana challenge the popular model of thrust belt internal deformation and shortening. A variety of deformation fabrics exist at the microscopic and mesoscopic scales, including pervasive axial-planar pressure-solution cleavage, boudinage, pencil structures, deformed oolitic and pelletal carbonate grains, distributed shear zones, and a host of extension and shear fractures. These features demonstrate that these rocks have experiences substantial internal finite strains. The internal strains are primarily the result of layer-parallel longitudinal shortening, coupled with pure and simple shear. These observations are important for the following reasons. (1) The amount of total shortening across the fold-and-thrust belt has been traditionally underestimated, producing errors in palinspastic facies maps. (2) Internal deformational fabrics are important controls on reservoir heterogeneity and permeability. (3) Recognition of internal deformation requires the reevaluation of dynamic and thermochemical models for foreland thrust belt formation.

Lageson, D.R. (Montana State Univ., Bozeman (United States))

1991-06-01

335

Testing and Analysis of a Thrust Stand System.  

National Technical Information Service (NTIS)

This report presents the results of a dynamic evaluation of a Thrust Stand System. The testing includes sinusoidal power measurements from 10 cps to 2000 cps using an electrodynamic shaker as the input force and step unload force input with a decay time o...

A. J. Couvillion N. G. Tinling

1966-01-01

336

Viscid/Inviscid Interaction Analysis of Thrust Augmenting Ejectors.  

National Technical Information Service (NTIS)

A method has been developed for calculating the static performance of thrust augmenting ejectors by matching a viscous solution for the flow through the ejector to an inviscid solution for the flow outside the ejector. In effect, the ejector shroud is con...

P. M. Bevilaqua A. D. DeJoode

1978-01-01

337

Regenerative cooling for liquid propellant rocket thrust chambers  

Microsoft Academic Search

This work describes a calculation model for regeneratively cooled rocket thrust chambers. A computational program, based on a one-dimensional coolant pressure drop in the cooling channels. Radiation is included in the model. The channels have rectangular cross sections, the dimensions being determined during the calculations in order to maintain the wall temperature distributions at tolerable levels, with a minimum channel

Rafael Levy Rubin

1994-01-01

338

Flowfield performance prediction of a 2DCD vectored nozzle using self adaptive solution method  

NASA Astrophysics Data System (ADS)

The flowfield of a two-dimensional convergent-divergent (2DCD) vectored nozzle is analized using a self-adaptive solution-dependent grid-refinement method to obtain the Euler solution of the flowfield for the 2DCD nozzle geometry for several vectored positions. The pressure distribution from this analysis is compared with test data, demonstrating the computational accuracy of the numerical methods used in the analysis. Performance parameters such as the thrust coefficient, discharge coefficient, and thrust vector angle, are calculated for various 2DCD and axisymmetric nozzles and compared with test data. A comparison of predictions made with the adaptive unstructured grid of a complex shock structure in a 2DCD vectored nozzle with predictions made with a structured grid using the same geometry and flow conditions demonstrated the advantage of the adaptive grid.

Rowe, R. K.; Collopy, G. B.; Rout, R. K.

1991-06-01

339

Active tectonics of frontal thrust, southwestern Taiwan orogenic belt  

NASA Astrophysics Data System (ADS)

Thrust belts are characterized by great earthquakes, crustal shortening deformation, and extraordinary topographic relief and represent a fundamental manifestation of deformation in active orogenic belt. During the Quaternary period, Taiwan Orogen in arc-continent collisional convergent settings occurs as a result of the active thin-skin thrust belt which is displayed in the Western Foothills, western Taiwan. The Western Foothills represent a zone of ongoing convergence which shortening occurs in response to the thrusts westward movement. Recent geodetic studies indicate present shortening rates of ca. 40 mm/yr within the Western Foothills, southwestern Taiwan. It suggested high rates of deformation and is often considered to behave as a strong deformation within the southwestern Taiwan. In the study area is a ongoing deformation front which is dominated by a NE-SW trending structure fabric that consist of three active thrust faults. The geomorphic expression, which preserves a young surface features, is made up of five topographic and structural provinces of the Western Foothills, Chungchou Marine Terrace, Dawan Lowland, Tainan Tableland, and Chianan Coastal Plain from east to west which province due to the tectonic deformation were created during the late Pleistocene, that have been subsequently deformed by a major thrust of the Tainan fault and three imbricated faults of the Lungchuan, Meilin, and Chungchou faults. In this study we first use continuously cored boreholes to reconstruct the depositional architecture and 14C dating of the Holocene sediments, result of this analysis is able to assess the uplift rate and activity. The long-term vertical deformation rate of the Chianan Coastal Plain, Tainan Tableland, Dawan Lowland, Chungchou Marine Terrace, and Western Foothills was about -6 to 0, 0 to 5, -2 to 1, 1 to 4, and 6 to 7 mm/yr, respectively.

Chen, W.; Chou, F.; Yang, C.; Yang, H.

2009-04-01

340

Thrust Area Report, Engineering Research, Development and Technology  

SciTech Connect

The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the knowledge base, process technologies, specialized equipment, tools and facilities to support current and future LLNL programs. Engineering`s efforts are guided by a strategy that results in dual benefit: first, in support of Department of Energy missions, such as national security through nuclear deterrence; and second, in enhancing the nation`s economic competitiveness through our collaboration with U.S. industry in pursuit of the most cost- effective engineering solutions to LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) identify key technologies relevant to LLNL programs where we can establish unique competencies, and (2) conduct high-quality research and development to enhance our capabilities and establish ourselves as the world leaders in these technologies. To focus Engineering`s efforts technology {ital thrust areas} are identified and technical leaders are selected for each area. The thrust areas are comprised of integrated engineering activities, staffed by personnel from the nine electronics and mechanical engineering divisions, and from other LLNL organizations. This annual report, organized by thrust area, describes Engineering`s activities for fiscal year 1996. The report provides timely summaries of objectives, methods, and key results from eight thrust areas: Computational Electronics and Electromagnetics; Computational Mechanics; Microtechnology; Manufacturing Technology; Materials Science and Engineering; Power Conversion Technologies; Nondestructive Evaluation; and Information Engineering. Readers desiring more information are encouraged to contact the individual thrust area leaders or authors. 198 refs., 206 figs., 16 tabs.

Langland, R. T.

1997-02-01

341

Elimination of Intermediate-Frequency Combustion Instability in the Fastrac Engine Thrust Chamber.  

National Technical Information Service (NTIS)

A series of tests were conducted to measure the combustion performance of the Fastrac engine thrust chamber. The thrust chamber exhibited benign, yet marginally unstable combustion. The marginally unstable combustion was characterized by chamber pressure ...

M. Rocker T. E. Nesman

2001-01-01

342

Overview of the Capabilities of ARA for the Measurement of Nozzle Discharge and Thrust.  

National Technical Information Service (NTIS)

Details are given of the present nozzle thrust and discharge measuring ability of Aircraft Research Association (ARA) and the practical application of the measurements explained. Two major facilities for the measurement of thrust and discharge, the Mach S...

R. S. Sale M. Elliott I. F. Burns

1992-01-01

343

Low-Thrust Mission Risk Analysis, with Application to a 1980 Rendezvous with the Comet Encke.  

National Technical Information Service (NTIS)

A computerized failure process simulation procedure is used to evaluate the risk in a solar electric space mission. The procedure uses currently available thrust-subsystem reliability data and performs approximate simulations of the thrust sybsystem burn ...

C. L. Yen D. B. Smith

1973-01-01

344

Time of initial thrusting in the Sevier orogenic belt, Idaho-Wyoming and Utah  

Microsoft Academic Search

Reexamination of the distribution of fossils found in the earliest preserved synorogenic conglomerates within the Sevier thrust belt suggests that initial thrust movement may be no older than Aptian age. This interpretation is corroborated by subsidence analyses of sedimentary sequences lying within and east of the Idaho-Wyoming and Utah thrust belts. A major episode of middle Cretaceous (Aptian Cenomanian) subsidence

P. L. Heller; S. S. Bowdler; H. P. Chambers; J. C. Coogan; E. S. Hagen; M. W. Shuster; N. S. Winslow; T. F. Lawton

1986-01-01

345

Time of initial thrusting in the Sevier orogenic belt, Idaho-Wyoming and Utah  

Microsoft Academic Search

Reexamination of the distribution of fossils found in the earliest preserved synorogenic conglomerates within the Sevier thrust belt suggests that initial thrust movement may be no older than Aptian age. This interpretation is corroborated by subsidence analyses of sedimentary sequences lying within and east of the Idaho-Wyoming and Utah thrust belts. A major episode of middle Cretaceous (Aptian-Cenomanian) subsidence is

P. L. Heller; S. S. Bowdler; H. P. Chambers; J. C. Coogan; E. S. Hagen; M. W. Shuster; N. S. Winslow; T. F. Lawton

1986-01-01

346

The effect of compliant joint and caudal fin in thrust generation for robotic fish  

Microsoft Academic Search

Fish generates large thrust through an oscillating motion with a fin. It is assumed that the flexibility of a fin affects the thrust generated by the fish. However, detailed investigation on the relationship between the flexibility of the fin and thrust generation is lacking. In this paper, the driving mechanism of a robotic fish is implemented using a compliant joint

Yong-Jai Park; Useok Jeong; Jeongsu Lee; Ho-Young Kim; Kyu-Jin Cho

2010-01-01

347

OPTIMIZATION OF THRUST ALLOCATION IN THE PROPULSION SYSTEM OF AN UNDERWATER VEHICLE  

Microsoft Academic Search

The paper addresses methods of thrust distribution in a propulsion system for an unmanned underwater vehicle. It concen- trates on finding an optimal thrust allocation for desired values of forces and moments acting on the vehicle. Special attention is paid to the unconstrained thrust allocation. The proposed methods are developed using a configuration matrix describ- ing the layout of thrusters

JERZY GARUS

2004-01-01

348

Deformation in footwall of Clinchport thrust, valley and ridge of northwest Georgia  

SciTech Connect

The footwall of the Clinchport thrust in northwest Georgia contains small-displacement reverse faults, blind thrusts, and related small anticlines involving the Lower Silurian Red Mountain Formation which, because of its erosion resistance, has given rise to a distinctive topographic pattern. The eastern limb of a large syncline, adjacent to and overridden by the Clinchport thrust, is overturned in places and is faulted throughout its length. Deformation increases with proximity to the Clinchport thrust. Petrographic analyses show twinned carbonate crystals and veinlets in carbonate units and microfaults in sandstone units near the Clinchport thrust, whereas samples from the same horizon 3-5 mi westward, away from the Clinchport thrust, have no similar features. Smaller scale anticlines adjacent to the Clinchport thrust are superimposed on the eastern limb of the major syncline. Thin-skinned tectonic interpretation and unique fold axial directions support their origin by blind thrusting. Some of these anticlines are faulted by small-displacement reverse faults, which are prevalent in the footwall along the length of the Clinchport thrust. All features are interpreted as having formed in the footwall during a single deformational event as a response to continued movement on the Clinchport thrust plane. This type of footwall deformation probably exists adjacent to other Valley and Ridge thrusts. The presence of the Clinchport thrust near the highly resistant Red Mountain Formation results in topographic relief which makes the structure discernible.

Morris, W.L.

1987-05-01

349

14 CFR 25.1155 - Reverse thrust and propeller pitch settings below the flight regime.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Reverse thrust and propeller pitch settings below the flight regime...Accessories § 25.1155 Reverse thrust and propeller pitch settings below the flight regime. Each control for reverse thrust and for propeller pitch settings below the...

2013-01-01

350

Optical Proper Motion Measurements of the M87 Jet: New Results from the Hubble Space Telescope  

NASA Astrophysics Data System (ADS)

We report new results from a Hubble Space Telescope archival program to study proper motions in the optical jet of the nearby radio galaxy M87. Using over 13 yr of archival imaging, we reach accuracies below 0.1c in measuring the apparent velocities of individual knots in the jet. We confirm previous findings of speeds up to 4.5c in the inner 6'' of the jet, and report new speeds for optical components in the outer part of the jet. We find evidence of significant motion transverse to the jet axis on the order of 0.6c in the inner jet features, and superluminal velocities parallel and transverse to the jet in the outer knot components, with an apparent ordering of velocity vectors possibly consistent with a helical jet pattern. Previous results suggested a global deceleration over the length of the jet in the form of decreasing maximum speeds of knot components from HST-1 outward, but our results suggest that superluminal speeds persist out to knot C, with large differentials in very nearby features all along the jet. We find significant apparent accelerations in directions parallel and transverse to the jet axis, along with evidence for stationary features in knots D, E, and I. These results are expected to place important constraints on detailed models of kiloparsec-scale relativistic jets.

Meyer, Eileen T.; Sparks, W. B.; Biretta, J. A.; Anderson, Jay; Sohn, Sangmo Tony; van der Marel, Roeland P.; Norman, Colin; Nakamura, Masanori

2013-09-01

351

Jet Reconstruction and Spectroscopy at Hadron Colliders  

NASA Astrophysics Data System (ADS)

Dear colleagues and friends, Major new particle discoveries were made in the past by exploring the mass spectrum of lepton pairs. These searches still have great potential. However, new particle searches are now being extended to masses larger than the W, Z mass. More and more decay channels open up and the branching ratios into lepton pairs are reduced. Also, physics may dictate that states with heavy bosons and quarks become dominant. Examples are the decay of top quarks, and the expected final states of the standard model Higgs boson. Supersymmetry in any of its wide spectrum of models predicts intrigued final states where jets are major observables. To reconstruct masses and to study the dynamics of these states one must exploit the energy-momentum four-vectors of jets. Past experiments at the CERN SPS collider, at HERA, at LEP and now at the Tevatron collider and at LHC, have studied how best to reconstruct hadron jets. However, originally the role of jets in searching for new physics was primarily to sense new parton contact interactions by means of increased large pt tails in inclusive jet spectra, or studying jet events with large missing Et, or measuring branching ratios into jets of different flavour. These studies did not require as accurate a measure of jet four-momenta as needed in new particle searches in multi-jets final states. Figure 1 Figure 1. W, Z associated production in CDF events with large Et, miss and 2 jets. Consider for example (figure 1) the mass spectrum of dijets in events with large missing Et recently measured by CDF [1]. Trigger and analysis cuts were chosen so as to favour production of heavy boson pairs, with decay of one Z boson into neutrinos tagging the event and another W or Z boson decaying into jets. Associated production of boson pairs is observed, but the dijet mass resolution does not allow the separation of W from Z. A broad agreement of the overall observed rate with expectation is found, but a comparative study of the two processes cannot be made. The feeling of uneasiness becomes much worse by observing (figure 2) the invariant mass distribution of jet pairs produced in association with a W boson at dijet masses larger than the W, Z, recently studied by CDF [2]. Evidence is shown for a wide bump around 145 GeV/c2 which cannot be explained by known processes. Assuming that it is new physics, we do not know whether a single new state or a superposition of several processes is being observed. In an attempt to strengthen the significance of the result one would like to split this spectrum into jet flavour channels. Since the expected background is primarily composed by gluon jets, it ought to be different in different channels. The new process might stand up more prominently in some flavour-specific channel. However, at the present time this study can only be performed accurately for beauty-flavoured jets. Accurate flavour tagging for all jet flavours to include, in particular, gluon jets would be needed. Extending jet flavour studies much beyond the accuracy presently available is mandatory. Figure 2aFigure 2b Figure 2. Mass spectrum of dijets in W production events. The role of theory is extremely important for ensuring success to a renewed jet spectroscopy effort. Part of the theory effort would be in phenomenology. Tagging jet flavour requires an understanding of flavour-dependent jet fragmentation. This goal can be pursued by detailed measurements of jets of known flavour combined with their accurate phenomenological description. A probability tag for each flavour choice could become a standard 'observable' to be quoted as a jet parameter. Precise perturbative calculations can be made of the kinematical structure of the final state of multi-jets of heavy particle events. This is true for W, Z and top quark as well as for new exotic particles. Theoretical input will be vital in understanding the physics of such events. Such an input might be necessary for discovering new particles. Jet spectroscopy, as difficult as it might be, is a vital field of research. We should not gi

Bellettini, Giorgio

2011-11-01

352

Vector Addition Model  

NSDL National Science Digital Library

The Vector Addition model allows the user to practice vector addition of two vectors in two dimensions. You are given the magnitude and direction of the two vectors, and your goal is to fill in the nine values in the table (showing the x-component, y-component, and length) of the two vectors, and the resultant vector that is the sum of the first two vectors. The Vector Addition was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_addition.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-25

353

Date and origin of fluid flow events along the Moine Thrust, NW Scotland  

NASA Astrophysics Data System (ADS)

In this study, paleomagnetic and geochemical methods were used to date and determine the origin of fluids which migrated along the Moine Thrust Zone, NW Scotland. Torridon Sandstone (Precambrian) and Cambrian-Ordovician limestones/quartzites in and near the fault zone contain three magnetizations with southerly declinations and shallow to steep negative inclinations. A fold test indicates that a magnetization with southerly declinations and shallow negative inclinations is post tilting and the pole position (Lat: 37.4°, Long: 168.4°) suggests it is Permian in age. This remagnetization is localized in the fault zone and decreases away from the fault zone, suggesting that remagnetizing fluids moved along the fault zone and dissipated outward. On the Isle of Skye, the Torridon Sandstone and Lewisian Gneiss (Precambrian) in the fault zone contain a Tertiary magnetization with southerly declinations and steep negative inclinations. A third magnetization with southerly declinations and moderate up inclinations is found in some samples and is interpreted as a Triassic magnetization or a vector addition of the Permian and the Tertiary magnetizations. Some samples of the Torridon Sandstone also contain a primary magnetization or an early remagnetization. Rock magnetic results indicate that the magnetizations reside in hematite and petrographic studies identify abundant authigenic hematite. Fluid inclusion/isotopic studies indicate that the altering fluids were basinal in origin. The magnetizations are interpreted as chemical remanent magnetizations (CRMs) that were acquired when fluids migrated in the fault zone and precipitated hematite. On Skye, the CRM is the result of hydrothermal fluids associated with Tertiary intrusions. The Permian CRM and associated alteration are direct evidence for post-orogenic activity, in which the thrusts vented excess heat during regional crustal extension.

Blumstein, R.; Elmore, R. D.; Engel, M.; Parnell, J.

2003-04-01

354

Rates and spin properties of hadrons in jets  

Microsoft Academic Search

The hadronic Z0 decays, recorded by the OPAL detector at LEP, have been used to study strange hadron rates in quark and gluon jets and to determine the spin alignment of the ?(1020), D? and B? vector mesons. A first measurement of the spin content of the ?? and ??(??) systems is also presented.

G. Alexander; I. Cohen

1998-01-01

355

AEROACOUSTIC CHARACTERISTICS OF A RECTANGULAR MULTIELEMENT SUPERSONIC JET MIXER–EJECTOR NOZZLE  

Microsoft Academic Search

This paper provides a unique, detailed evaluation of the acoustics and aerodynamics of a rectangular multi-element supersonic jet mixer–ejector noise suppressor. The performance of such mixer–ejectors is important in aircraft engine applications for noise suppression and thrust augmentation. In contrast to most prior experimental studies on ejectors that reported either aerodynamicoracoustic data, the present work documentsbothtypes of data. Information on

G. Raman; R. Taghavi

1997-01-01

356

Interpretation of extragalactic jets  

SciTech Connect

The nature of extragalatic radio jets is modeled. The basic hypothesis of these models is that extragalatic jets are outflows of matter which can be described within the framework of fluid dynamics and that the outflows are essentially continuous. The discussion is limited to the interpretation of large-scale (i.e., kiloparsec-scale) jets. The central problem is to infer the physical parameters of the jets from observed distributions of total and polarized intensity and angle of polarization as a function of frequency. 60 refs., 6 figs.

Norman, M.L.

1985-01-01

357

Properties of gluon jets  

SciTech Connect

The properties of gluon jets are reviewed from an experimental point of view. The measured characteristics are compared to theoretical expectations. Although neither data nor models for the gluon jets are in the mature stage, there are remarkable agreements and also intriguing disagreements between experiment and theory. Since much interesting data have begun to emerge from various experiments and the properties of gluon jets are deeply rooted in the basic structure of non-Abelian gauge theory, the study of gluon jets casts further light on our understanding of QCD. Finally, the future prospects are discussed.

Sugano, K.

1986-09-01

358

Baroclinic splitting of jets  

NASA Astrophysics Data System (ADS)

Whether the split of the Somali jet, sometimes seen on monthly mean streamline analyses, is a climatological or a dynamical feature has been the subject of long-standing debate. This paper explores the dynamical conditions leading to a split jet within the framework of a simple barotropic dynamic system. The initial conditions for the dynamical system, along with three other parameters the jet width, the zonal wavelength, and the latitude of the ?-plane, form a parameter space for the problem consisting of a range of solutions for the evolution of the jet. This paper identifies a region in the parameter space in which these solutions support a splitting of the jet. The width and wavelength of the Somali jet determined from observations are such that for most initial conditions the solutions reside near the boundary in parameter space between the split and non-split regions. It is therefore concluded that the splitting of the Somali jet can be a dynamical feature given the observed jet width and wavelength. Whether a split does or does not occur is determined by the parameters defining the initial zonal mean and perturbation flow in the jet, with the solution being highly sensitive to these initial conditions.

Thompson, A.; Stefanova, L.; Krishnamurti, T. N.

2008-08-01

359

Hinterland-vergent tectonic wedge below the Riwat thrust, Himalayan foreland, Pakistan: Implications for hydrocarbon exploration  

SciTech Connect

The Riwat thrust, with a surface trace of over 50 km, is one of the major faults in the footwall of the main boundary thrust in the Himalayan foreland of Pakistan. Surface geology shows that the Riwat thrust is a foreland-vergent thrust along which lower to middle Siwalik molasse strata are thrust southward over upper Siwalik strata. Seismic reflection interpretation shows that the Riwat thrust developed as a roof thrust of a hinterland-vergent tectonic wedge (triangle zone) underlain by evaporites. The Riwat thrust propagates upsection from depth of about 4 km at the base of the Siwalik Group. At this depth, it merges into a hinterland-vergent blind thrust that propagates upsection as a ramp from Eocambrian evaporites covering the basement at a depth of about 6 km. Bounded between this set of conjugate faults, a tectonic wedge of Eocambrian (evaporites) to Neogene strata is thrust toward the hinterland to form a triangle zone. The roof thrusts of triangles zones have been widely mapped as backthrusts in deformed mountain fronts. Hinterland motion of tectonic wedges as in the Riwat thrust triangle zone may be a feature of the fold-and-thrust belts underlain by evaporites acting as an extremely weak decollement layer. Their recognition, with a trap-forming geometry below a thrust, is important for interpreting particular fold belts and for hydrocarbon exploration. These structures could be predicted by the surface geology data where hinterland vergence of a fold below a thrust is apparent; however, seismic reflection data appear to be critical in recognizing these structures.

Jadoon, I.A.K. [Quaid-i-Azam Univ., Islamabad (Pakistan); Frisch, W. [Eberhard-Karls-Universitaet Tuebingen (Germany)

1997-03-01

360

Numerical modeling of seismogenic stress pattern and cohesive strength along the Main Himalayan décollement thrust zone, NW-Himalaya  

NASA Astrophysics Data System (ADS)

Cohesive strength of the fault zones can play a pivotal role to accumulate seismogenic stress for the future earthquake during the interseismic period, and mainly controlled by several factors especially coseismic stress drop, recovery rates of stresses (shear/normal) and change in cohesion and angle of internal friction within the fault zone. Moreover, significant mineralogical changes, existing heat flow and fluid-rock reactions in the fault zone further affect the cohesive strength of the fault. In this contribution, we have present series of 2-D finite element numerical modeling experiments that incorporate faults, elastic rheology, topographic load due to gravity and plate velocity boundary conditions. A plain strain models presented here to understand and quantify the role of cohesive strength in interseismic period and its effect on interseismic deformation and earthquake generation in the Himalayan fold-and-thrust belt. In present study, we tested different values of cohesion ranged from 1 (weak fault) to 25 (strong fault) and angle of internal friction ranged from 10 (weak fault)to 60 (strong fault)consistent of the natural conditions of weak and strong faults. Morh-Coulomb failure criterion with different rock mechanical properties were applied to examine fault type. Numerical modeling results presented here are based on (i) orientation, distribution and magnitude of principle stresses (ii) strain distribution (iii) displacement vectors, and (iv) distribution and concentration of maximum shear stress contour lines. In case of weak fault assumption, simulation results show that the significant compressive stress and strain are mainly distributed along the Main Himalayan décollement thrust. However, in case of strong fault condition, there are no failure occurred along the Main Himalayan décollement thrust but the significant amount of maximum shear stress is accumulated in the northern segment of the Main Himalayan décollement thrust at shallow crustal depth. On the basis of simulation results we conclude that the cohesive strength have important role to accumulate considerable amount of seismogenic stress/strain in interseismic period to produce medium to large scale earthquakes along the active fault zone. Keywords: cohesive strength, fault zone, interseismic period, Himalayan décollement thrust, numerical modeling, NW-Himalaya

Joshi, Ganesh Raj; Hayashi, Daigoro

2010-05-01

361

30 CFR Jet - Surface Only  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Surface Only Jet Rotary Jet Piercing Mineral Resources MINE SAFETY AND HEALTH...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface and Underground §...

2010-07-01

362

Strain rate relaxation of normal and thrust faults in Italy  

NASA Astrophysics Data System (ADS)

We find that geodetic strain rate (SR) integrated with the knowledge of active faults points out that hazardous seismic areas are those with lower SR, where active faults are possibly approaching the end of seismic cycle. SR values estimated from GPS velocities at epicentral areas of large historical earthquakes in Italy decrease with increasing elapsed time, thus highlighting faults more prone to reactivation. We have modelled an exponential decrease relationship between SR and the time elapsed since the last largest earthquake, differencing historical earthquakes according to their fault rupture style. Then, we have estimated the characteristic times of relaxation by a non-linear inversion, showing that events with thrust mechanism exhibit a characteristic time (˜ 990 yr) about three times larger than those with normal mechanism. Assuming standard rigidity and viscosity values we can infer an average recurrence time of about 600 yr for normal faults and about 2000 yr for thrust faults.

Riguzzi, Federica; Crespi, Mattia; Devoti, Roberto; Doglioni, Carlo; Pietrantonio, Grazia; Pisani, Anna Rita

2013-11-01

363

Strain rate relaxation of normal and thrust faults in Italy  

NASA Astrophysics Data System (ADS)

We find that geodetic strain rate (SR) integrated with the knowledge of active faults points out that hazardous seismic areas are those with lower SR, where active faults are possibly approaching the end of seismic cycle. SR values estimated from GPS velocities at epicentral areas of large historical earthquakes in Italy decrease with increasing elapsed time, thus highlighting faults more prone to reactivation. We have modelled an exponential decrease relationship between SR and the time elapsed since the last largest earthquake, differencing historical earthquakes according to their fault rupture style. Then, we have estimated the characteristic times of relaxation by a non-linear inversion, showing that events with thrust mechanism exhibit a characteristic time (˜ 990 yr) about three times larger than those with normal mechanism. Assuming standard rigidity and viscosity values we can infer an average recurrence time of about 600 yr for normal faults and about 2000 yr for thrust faults.

Riguzzi, Federica; Crespi, Mattia; Devoti, Roberto; Doglioni, Carlo; Pietrantonio, Grazia; Pisani, Anna Rita

2013-08-01

364

Slip vectors and fault mechanics in the Makran Accretionary Wedge, southwest Pakistan  

NASA Astrophysics Data System (ADS)

The Makran is a broadly east-west trending arcuate accretionary wedge currently forming where the oceanic floor of the Gulf of Oman is being subducted north-northeastward beneath the south Asian margin. Two traverses across the Makran Coast Ranges, extending about 80 km inland from the coastline (which lies about 100 km north of the wedge front), show that the structure of this region is dominated by large back-rotated south directed thrust faults and associated folds. Related structures include duplexes, fault gouge containing Reidel shears, and melange along fault zones. These structures are cut by later north directed backthrusts, out-of-sequence south directed thrusts, and apparently conjugate sets of NNE trending sinistral and NW trending dextral strike-slip faults. Slip vectors were determined from slickenlines, fiber lineations, gouge fabrics, and Riedel shears. Vectors from early thrusts and bedding-parallel slip surfaces, corrected for tectonic rotation, form a broad south directed concentration lying between the normal to the regional strike (varying from 160° to 180°) and the present plate convergence vector (200°). Locally, the concentration is bimodal. This pattern may represent the interaction between plate forces and body forces in the accretionary wedge. The late thrusts have widely variable slip vectors and stair-step off the early thrusts. They overlap in orientation and slip vector with gently dipping sinistral strike-slip faults, suggesting that they also stair-step in plan off the latter. The steep strike-slip faults represent the final tectonic stage, involving minor N-S shortening and longitudinal extension. These three stages probably occurred in sequence in any one area but migrated diachronously southward as the wedge grew.

Platt, John Paul; Leggett, Jeremy K.; Alam, S.

1988-07-01

365

Direct thrust measurement of a permanent magnet helicon double layer thruster  

NASA Astrophysics Data System (ADS)

Direct thrust measurements of a permanent magnet helicon double layer thruster have been made using a pendulum thrust balance and a high sensitivity laser displacement sensor. At the low pressures used (0.08 Pa) an ion beam is detected downstream of the thruster exit, and a maximum thrust force of about 3 mN is measured for argon with an rf input power of about 700 W. The measured thrust is proportional to the upstream plasma density and is in good agreement with the theoretical thrust based on the maximum upstream electron pressure.

Takahashi, K.; Lafleur, T.; Charles, C.; Alexander, P.; Boswell, R. W.; Perren, M.; Laine, R.; Pottinger, S.; Lappas, V.; Harle, T.; Lamprou, D.

2011-04-01

366

Finite element analysis of direct thrust-controlled linear induction motor  

SciTech Connect

This paper describes the finite element analysis of a direct thrust-controlled linear induction motor (LIM). The time-stepping finite element method and the moving mesh technique are used to calculate the dynamic characteristics of LIM during the direct thrust control. Because LIM has the end effect, thrust correction coefficient is introduced to predict an actual thrust in control. The simulation results, the thrust and the stator flux linkage are shown below and the stator current is compared with an experimental one.

Kwon, B.I.; Woo, K.I.; Kim, S. (Hanyang Univ., Ansan (Korea, Republic of). Dept. of Electrical Engineering)

1999-05-01

367

Direct thrust measurement of a permanent magnet helicon double layer thruster  

SciTech Connect

Direct thrust measurements of a permanent magnet helicon double layer thruster have been made using a pendulum thrust balance and a high sensitivity laser displacement sensor. At the low pressures used (0.08 Pa) an ion beam is detected downstream of the thruster exit, and a maximum thrust force of about 3 mN is measured for argon with an rf input power of about 700 W. The measured thrust is proportional to the upstream plasma density and is in good agreement with the theoretical thrust based on the maximum upstream electron pressure.

Takahashi, K.; Lafleur, T.; Charles, C.; Alexander, P.; Boswell, R. W. [Space Plasma, Power and Propulsion Group, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Perren, M.; Laine, R. [ASTRIUM-EADS, 6 rue Laurent Pichat, 75016 Paris (France); Pottinger, S.; Lappas, V.; Harle, T.; Lamprou, D. [Surrey Space Centre, University of Surrey, Guildford GU2 7XH (United Kingdom)

2011-04-04

368

Optimization of the Thrust Performance of a Pulsed Detonation Engine  

Microsoft Academic Search

The problem of modeling the operation cycle of a pulse detonation engine and estimating its highest possible thrust performance\\u000a is considered. Self-similar and non-self-similar flows in an axisymmetric duct of finite length and variable cross section\\u000a which arise from detonation propagation from the closed end of the duct are studied for the model of an infinitely thin detonation\\u000a wave. Analytical

V. A. Levin; I. S. Manuilovich; V. V. Markov

2010-01-01

369

Thrust Production and Wake Structure of an Actuated Lamprey Model  

NASA Astrophysics Data System (ADS)

Thrust generation is studied for a flexible lamprey model which is actuated periodically to produce a streamwise traveling wave. Shape memory alloy actuators are used to achieve this deformation. The flow field is investigated using DPIV and flow visualization for a range of Strouhal numbers based on peak-to-peak amplitude of the trailing edge. The vortex kinematics in the spanwise and streamwise planes are examined, and a three-dimensional unsteady vortex model of the wake will be discussed.

Buchholz, James; Smits, Alexander

2004-11-01

370

Biomimetic thrust production with a modified Schmidt wave propeller  

Microsoft Academic Search

An important feature of fish-like swimming is the interaction of large-scale body-shed vortices with an oscillating tail fin. The vortices are sensed along the sides of the body before reaching the tail fin and if the motion of the tail fin is actively coordinated with the arrival of the oncoming vortices, thrust can be produced very efficiently. A Schmidt wave-propeller

Karl von Ellenrieder; Joe Buzard; Hannuman Bull

2004-01-01

371

A lithospheric-scale seismogenic thrust in central Italy  

Microsoft Academic Search

In this paper, the relatively deep (up to 90 km) seismicity of central Italy is considered in comparison with the upper crust seismicity at the outer front of the Apennine fold-and-thrust belt system and with the major crust-scale tectonic discontinuities outlined by deep crust seismic reflection and refraction profiles. In particular, attention is given to the presence of a Plio-Quaternary

Giusy Lavecchia; Paolo Boncio; Nicola Creati

2003-01-01

372

Drainage responses to oblique and lateral thrust ramps: a review  

Microsoft Academic Search

The relationships between oblique or lateral ramps in fold-and-thrust belts and their impact on syntectonic fluvial drainage are analysed in this review. Both ancient and recent cases from Cenozoic belts are examined. The southern flank of the Pyrenees provides good examples to decipher the long-term effects of oblique ramps on fluvial arrangement. Recent examples from the Indus River across the

JAUME VERGÉS

373

Particle image velocimetry and thrust of flagellar micro propulsion systems  

NASA Astrophysics Data System (ADS)

Miniature smart devices and micro-swimming robots that can perform in vivo interventions and diagnostic procedures inside the human body require efficient low Re number propulsions systems. A static test-bench to acquire simultaneous thrust and 3D velocity measurements of flagellar micro-propulsion systems is developed. Validation experiments of this set-up involving full computational fluid dynamics (CFD) solutions and approximate Resistive Force Theory (RFT) comparisons at variable rotational speeds (5-13 Hz) and for two different parametric thruster configurations are performed up to Re=0.1. 3D velocity fields are obtained with both side view and bottom view PIV configurations are evaluated for the single helix flagellar thruster configuration. To calculate the control volume thrust 20 PIV slices (acquired by 18 degrees shift of the encoder trigger signal) are interpolated on a cylindrical volumetric grid. CFD studies are in progress. A comparison between PIV results, thrust-cell measurements and RFT theory indicated high sensitivity on RFT drag coefficients. In future studies this measurement protocol will be applied to alternative and non-conventional bio-inspired thruster-configurations.

Danis, Umit; Sitti, Metin; Pekkan, Kerem

2008-11-01

374

Taconian foreland-style thrust system in the Great Smoky Mountains, Tennessee  

NASA Astrophysics Data System (ADS)

Four major thrust faults dominate the Great Smoky Mountains foothills region: the Greenbrier, Dunn Creek, Miller Cove, and Great Smoky. The Greenbrier and Dunn Creek thrust sheets were emplaced prior to Taconian regional cleavage development and peak metamorphism. Cleavage and most deformation features formed during the emplacement of a thrust sheet now floored by the Miller Cove thrust fault. Alleghanian emplacement of the Great Smoky-Miller Cove thrust sheet dissected these earlier structures. If the effects of the younger structures are removed, the basal faults of the Dunn Creek and Greenbrier sheets reveal ramp- flat geometries typical of foreland fold-thrust belts including bedding-parallel faults, ramps, and angular ramp-related folds. The Great Smoky Mountains region is therefore unique in the southern Appalachians because a foreland-style fold- thrust belt of Taconian age is well preserved.

Connelly, Jeffrey B.; Woodward, Nicholas B.

1992-02-01

375

Jet A Volatility Survey.  

National Technical Information Service (NTIS)

In response to the July 1996 TWA Flight 800 disaster, the Federal Aviation Administration (FAA) collected jet fuel samples from domestic and international flights to determine the actual flash point of jet fuel in service. This data was collected to help ...

S. Byrnes

2007-01-01

376

Plasma heating in JET  

Microsoft Academic Search

Heating the JET plasma well above temperatures reached in the ohmic phase is the aim of the two additional heating systems planned for JET: ion cyclotron resonance heating (ICRF) and neutral beam injection (NBI). Operations with the latter started in February 1986, initially with hydrogen injection, up to a power level of 7 MW. ICRF power has been delivered to

A. Ainsworth; H. Altmann; R. J. Anderson; J. Arbez; D. Bartlett; W. Bailey; K. Behringer; E. Bertolini; P. Bertoldi; C. H. Best; V. Bhatnagar; R. J. Bickerton; G. Boissin; T. Bonicelli; S. Booth; A. Boschi; G. Bosia; M. Botman; H. Brelen; H. Brinkschulte; M. L. Browne; M. Brusati; T. Budd; M. Bures; P. Butcher; H. Buttgereit; D. Cacaut; C. Caldwell-Nichols; D. Campbell; J. Carwardine; G. Celentano; C. D. Challis; A. Cheetman; J. Christiansen; C. Christodoulopoulos; P. Chuilon; R. Claesen; J. P. Coad; M. Cooke; J. G. Cordey; W. Core; S. Corti; A. E. Costley; G. Cottrell; J. Dean; E. Deksnis; G. Deschamps; K. J. Dietz; J. Dobbing; S. E. Dorling; D. F. Duechs; G. Duesing; H. Duquenoy; L. de Kock; A. Edwards; W. Engelhardt; F. Erhorn; B. Eriksson; H. Falter; T. Hellsten; J. L. Hemmerich; R. Hemsworth; F. Hendriks; R. F. Herzog; L. Horton; J. How; M. Huart; A. Hubbard; M. Hugon; P. Jones; J. Kaeline; A. Kaellne; A. Kaye; B. E. Keen; M. Keilhacker; G. Kinahan; A. Konstantellos; P. Kupschus; P. Lallia; J. R. Last; N. Foden; C. Froger; K. Fullard; A. Galetsas; A. Gallacher; A. Gibson; R. D. Gill; A. Geode; A. Gondhalekar; N. A. Gottardi; C. Gowers; R. Granetz; B. Green; S. Gregoli; F. S. Griph; R. Haange; C. J. Hancock; P. Harbour; R. F. Herog; J. Kaellne; L. Lauro-Taroni; E. Lazzaro; R. C. Lobel; P. Lomas; M. Lorenzo-Gottardi; C. Lowry; G. Magyar; D. Maissonneir; M. Malacarne; V. Marchese; P. Massmann; P. McMullen; M. J. Mead; P. Meriguet; V. Merlo; S. Mills; P. Millward; A. Moissonnier; P. L. Mondini; P. Morgan; G. Murphy; M. F. Nave; L. Nickesson; P. Nielson; P. Noll; S. Nowak; W. Obert; B. Oliver; M. Olsson; J. O'Rourke; M. G. Pacco; J. Paillere; L. Pannacione; S. Papastergiou; D. Pasini; M. Pescatore; J. Planncoulaine; J. P. Poffe; R. Prentice; T. Raimondi; C. Raymond; P. H. Rebut; J. Removille; W. Riediker; R. Roberts; A. Rolfe; R. T. Ross; G. Sadler; J. Saffert; N. Salmon; A. Sand; A. Santagiustina; R. Saunders; M. Schmid; F. C. Schueller; K. Selin; R. Shaw; D. Sigournay; R. Simonini; P. Smeulders; L. Sonnerup; K. Sonnenberg; M. Stamp; C. A. Steed; D. Stork; P. E. Stott; T. E. Stringer; D. Summers; A. Tanga; A. Taroni; A. Terrington; A. Tesini; P. R. Thomas; E. Thompson; F. Tibone; R. Tivery; E. Usselmann; H. Van der Beken; M. Von Hellerman; J. E. Van Montfoort; T. Wade; C. Walker; B. A. Wallander; M. Walravens; K. Walter; M. L. Watkins; M. Watson; D. Webberley; J. Wesson; J. Wilks; T. Winkel; C. Woodward; M. Wykes; D. Young; L. Zennelili; J. Zwart; B. Beaumont; D. Gambier; D. Moreau; J. Ehrenberg; H. Jaeckel; S. Kissel; U. Kuephnapfel; R. Mueller; A. Staebler; A. Weller; J. H. Hamnen; M. Evrared; M. Gadeberg; K. Thomsen; P. Dupperrex; G. Tonetti; N. Lopez-Cardozo; B. Tubbing; J. Von Seggern; J. Tagle; F. Bombarda; G. Bracco; R. Giannella; R. Carolan; M. Cox; M. Forrest; D. Goodall; N. Hawkes; P. Haynes; J. Hugill; K. D. Lawson; G. McCracken; J. Partridge; N. Peacock; J. Snipes; T. Todd; H. Schamel; H. Summers; S. Tsuji; G. Tallents

1986-01-01

377

Jet Flap Diffuser Ejector.  

National Technical Information Service (NTIS)

The use of a jet flap diffuser for recovery of ejector jet kinetic energy has been investigated in a two-dimensional experiment, utilizing an ejector which employs a Coanda inlet for ninety degree rotation of the primary flow. Performance is compared to a...

G. L. Marlotte M. Alperin

1971-01-01

378

The Structure and Linear Polarization of the Kiloparsec-scale Jet of the Quasar 3C 345  

NASA Astrophysics Data System (ADS)

Deep Very Large Array imaging of the quasar 3C 345 at 4.86 and 8.44 GHz has been used to study the structure and linear polarization of its radio jet on scales ranging from 2 to 30 kpc. There is a 7-8 Jy unresolved core with spectral index ? ~= -0.24 (I ?vprop??). The jet (typical intensity 15 mJy beam-1) consists of a 2.''5 straight section containing two knots, and two additional non-co-linear knots at the end. The jet's total projected length is about 27 kpc. The spectral index of the jet varies over -1.1 <~ ? <~ -0.5. The jet diverges with a semi-opening angle of about 9°, and is nearly constant in integrated brightness over its length. A faint feature northeast of the core does not appear to be a true counter-jet, but rather an extended lobe of this FR-II radio source seen in projection. The absence of a counter-jet is sufficient to place modest constraints on the speed of the jet on these scales, requiring ? >~ 0.5. Despite the indication of jet precession in the total intensity structure, the polarization images suggest instead a jet re-directed at least twice by collisions with the external medium. Surprisingly, the electric vector position angles in the main body of the jet are neither longitudinal nor transverse, but make an angle of about 55° with the jet axis in the middle while along the edges the vectors are transverse, suggesting a helical magnetic field. There is no significant Faraday rotation in the source, so that is not the cause of the twist. The fractional polarization in the jet averages 25% and is higher at the edges. In a companion paper, Roberts & Wardle show that differential Doppler boosting in a diverging relativistic velocity field can explain the electric vector pattern in the jet.

Roberts, David H.; Wardle, John F. C.; Marchenko, Valerie V.

2013-02-01

379

High-resolution rotational kinematics in fold-and-thrust belts; what is new and what is left to do?. The experience from the Southern Pyrenees  

NASA Astrophysics Data System (ADS)

The Southwestern Pyrenees are an excellent natural laboratory to study the evolution of fold-and-thrust belts (FAT belts). Together with outstanding outcropping conditions of syntectonic materials, the geometric and diachronic kinematic setting has produced a rotational FAT belt characterized by a complete catalogue of complex structures that includes superposed folding, conical and plunging folds, oblique thrust ramps, etc…. The application of paleomagnetic techniques in the Southwestern Pyrenees during the last decades has followed two complementary ways of research; on the one hand the highly dense characterization of rotations magnitudes (more than 2000 points) and, on the other side, the dating of synsedimentary piles and deformation processes by means of magnetostratigraphic studies (more than 85 km of series). Both techniques have been lately assembled together to characterize the rotational kinematics providing the first rotation speed values of single thrust sheets in FAT belts. Thrust sheets (as deduced from their associated anticlines; Pico del Aguila, Boltaña and Balzes) may rotate at rates reaching 20°/Ma although moderate magnitudes are more frequent around 10°/Ma. These kinematic data open a new way of understanding FAT belts in 4D (particularly the severe space problems). On the other hand, paleomagnetic vectors can now be used to restore complex folded geometries in 3D. A new method recently launched considers the paleomagnetic information to obtain more reliable reconstructions of the underground (Ramón et al., 2012-J. Struc. Geol.). In the External Sierras front two structures (Sto. Domingo and Balzes anticline) fulfilled the basic requirements to be restored using this methodology; they represent complex geometries (conical and curved geometries respectively), both have undergone important rotations and they are characterized by hundreds of paleomagnetic vectors evenly distributed and they are provided by high resolution magnetostratigraphic studies that have yield an accurate dating of the stratigraphic sequences and the recorded folding, thrusting and rotation times and rates. Despite this large, dense, detailed and reliable dataset some problems have arisen and should be tackled in the near future. The first one is related to the resolution and reliability of the datasets; how many data are needed to obtain a reliable vector in a portion of the FAT belt?, which criteria should be used to filter the noise at the sample, site and thrust sheet scales?. The second issue is related to the management of errors; apart from inclination flattening or non-dipolar records of the magnetic field, some sources of error (like the overlapping of vectors, internal deformation and incorrect restoration of vectors to the paleo-horizontal) are related to the geometry of folding (and thrusting). Some of them have been already studied in structural or paleomagnetic works but a thorough and comprehensive method to unravel at once all these systematic errors is still to be done. A comprehensive quantitative integration of structural and paleomagnetic data could change our view of the FAT belts in the future if these issues are satisfactorily resolved.

Pueyo, Emilio L.; José Ramón, Mª; Rodríguez-Pintó, Adriana; Oliva-Urcia, Belén; Mochales, Tania; Sánchez, Elisa; Pueyo-Anchuela, Oscar; Oliván, Carlota; López, Gelu; San Miguel, Galo

2013-04-01

380

Jet physics at CDF  

SciTech Connect

We present high E{sub T} jet measurements from CDF at the Fermilab Tevatron Collider. The incfilusive jet cross section at {radical}s = 1800 GeV with {approximately} 5 times more data is compared to the published CDF results, preliminary D0 results, and next-to-leading order QCD predictions. The {summation}E{sub T} cross section is also compared to QCD predictions and the dijet angular distribution is used to place a limit on quark compositeness. The inclusive jet cross section at {radical}s = 630 GeV is compared with that at 1800 GeV to test the QCD predictions for the scaling of jet cross sections with {radical}s. Finally, we present momentum distributions of charged particles in jets and compare them to Modified Leading Log Approximation predictions.

Melese, P.

1997-05-01

381

Studying Z/gamma*+Jet Production  

SciTech Connect

The production of jets in association with a Z/{gamma}* boson is an example of an important class of processes at hadron colliders, namely vector boson + jet (V + jet) production. Comparisons of measurements of this class of processes with theory predictions constitute an important, fundamental test of the Standard Model of particle physics, and of the theory of QCD in particular. While having a smaller cross section than other V +jet processes, Z/{gamma}*({yields} e{sup +}e{sup -}) + jets production, with Z/{gamma}* {yields} e{sup +}e{sup -}/{mu}{sup +}{mu}{sup -}, has a distinct experimental signature allowing for measurements characterized by low backgrounds and a direct, precise measurement of the properties of the decay products of the Z/{gamma}* boson. In this thesis, several new measurements of the properties of jets produced in association with a Z/{gamma}* boson in p{bar p} collisions at {radical}s = 1.96 TeV are presented. The cross section for Z/{gamma}*({yields} e{sup +}e{sup -}) + N jet production (N {le} 3) is measured, differential in the transverse momentum of the Nth jet in the event, normalized to the inclusive Z/{gamma}* cross section. Also, the cross section for Z/{gamma}*({yields} e{sup +}e{sup -}) + N jets (N {ge} 1) is measured, differential in the difference in azimuthal angle between the di-electron system and any jet in the event, normalized to unity. The data used in the measurements were collected by the D0 experiment located at the Tevatron Collider of the Fermi National Accelerator Laboratory and correspond to an integrated luminosity of 1.04 fb{sup -1}. The measured jet transverse momentum spectra are compared with the predictions of perturbative calculations at the next-to-leading order in the strong coupling constant. Given the low sensitivity of the calculations to model parameters, these comparisons represent a stringent test of perturbative QCD. One of the main goals currently being pursued in particle physics is the discovery of the only particle predicted by the Standard Model which has so far no been detected experimentally, namely the Higgs boson. It is assumed that the ATLAS and CMS experiments located at the Large Hadron Collider (LHC), a proton-proton collider at {radical}s = 14 TeV, will be able to detect the Higgs boson, or rule out its existence, within the next few years. The collisions delivered by the LHC will also be used to perform a long range of searches for other new particles, for instance particles predicted by models based on the principle of supersymmetry. The associated production of vector bosons with jets has relatively large production rates at the LHC and can produce a long list of different final states which can include charged leptons, missing transverse energy, as well as light- and heavy-flavour jets. This makes V + jet production a major source of background events to many searches for new particles. Most techniques used for estimating the expected number of background events to searches rely on passing the stable final-state particles of simulated hadron collisions generated using a so-called event generator code, through a simulation of the experimental detector system. The development of event generators which are capable of reliably predicting the properties of jets produced in association with a core process, e.g. the production of a vector boson, has been the subject of a large amount of research activity during the last ten years. These efforts have led to the appearance of the CKKW and MLM algorithms which are implemented in several event generators, among them SHERPA and ALPGEN + PYTHIA. The large data sample collected by the D0 experiment during Run II offers an excellent opportunity for validating these new event generators against experimental measurements of V + jet production. As argued above, the Z/{gamma}*({yields} e{sup +}e{sup -}) + jets process offers the combination of a clean experimental signature and large production rates, making it the process of choice for these studies.

Nilsen, Henrik Wold; /Freiburg U.

2009-07-01

382

Understanding jet scaling and jet vetos in Higgs searches.  

PubMed

Jet counting and jet vetos are crucial analysis tools for many LHC searches. We can understand their properties from the distribution of the exclusive number of jets. LHC processes tend to show either a distinct staircase scaling or a Poisson scaling, depending on kinematic cuts. We illustrate our approach in a detailed study of jets in weak boson fusion Higgs production. PMID:22400730

Gerwick, Erik; Plehn, Tilman; Schumann, Steffen

2012-01-18

383

Gravity sliding, thrusting, and petroleum traps in the Magdalena Basins and Cordillera Orientale, Colombia  

SciTech Connect

Major gravity slides on flanks of mountain belts can be misinterpreted as tectonic thrusts. They occur as synclines ([open quotes]fauteuils glisses[close quotes]) striking sub-parallel to dip slopes of major uplifts, overlie low-angle listric thrusts which pass upslope into listric or bedding-parallel normal faults, and may be associated with gravity-driven buried thrust fronts. The Nuevo Mondo syncline, underlain by the La Salinas thrust, and similar synclines along the east side of the Magdalena valley are interpreted as [open quotes]fauteuils glisses[close quotes], whose occurrence at the edge of the Cordillera Orientale creates an illusion of westward thrusting. Minor faults, formerly interpreted as east-dipping reverse faults along the west edge of the Cordillera Orientale are too small to have uplifted the Cordillera or to be correlatable with the major thrusts beneath synclines. They are reinterpreted as major west-dipping parallel faults, pass downslope westward beneath the synclines and/or into blind imbricate thrust structures. The Magdalena basins contain attractive east-verging tectonic thrust traps for hydrocarbons, and less attractive post-tectonic west-verging thrust traps formed by sliding down the east flank of the basin. Interpretation of these structures as post-deformational features allows modeling of the Cordillera Orientale as an overthrust sheet about 10 km thick that moved over 160 km southeastward. Its ramp underlies the east flank of the Magdalena basins. Its buried thrust front marks the edge of the Llanos basin.

Jones, P.B. (International Tectonic Consultants Ltd., Calgary, Alberta (Canada))

1993-02-01

384

Structural evidence for northeastward movement on the Chocolate Mountains thrust, southeasternmost Calfornia  

SciTech Connect

The Late Cretaceous Chocolate Mountains thrust of southeastern California and southwestern Arizona places a block of Proterozoic and Mesozoic continental crust over the late Mesozoic continental margin oceanic sedimentary and volcanic rocks of the regionally distinctive Orocopia Schist. The Chocolate Mountains thrust is interpreted as a thrust (burial, subduction) fault rather than a low-angle normal (exhumation, unroofing, uplift) fault. The Chocolate Mountains thrust zone contains sparse to locally abundant mesoscopic asymmetric folds. Fabric relations indicate that these folds are an integral part of and coeval with the thrust zone. On a lower hemisphere equal-area plot representing the orientation and sense of asymmetry of 80 thrust zone folds from 36 localities, spread over an area 60 by 10 km, Z folds plot northwest of and S folds plot southeast of a northeast-southwest striking vertical plane of overall monoclinic symmetry. The only sense of movement consistent with the collective asymmetry of the thrust zone folds is top to the northeast. Paleomagnetic data suggest that the original sense of thrusting, prior to Neogene vertical axis tectonic rotation related to the San Andreas fault system, was northward. The essential point is that movement of the upper plate of the Chocolate Mountains thrust evidently was continentward. Continentward thrusting suggests a tectonic scenario in which an insular or peninsular microcontinental fragment collided with mainland southern California. Alternative tectonic models involving subduction of the Orocopia Schist eastward beneath continental southern California circumvent the suture problem but are presently not supported by any direct structural evidence.

Dillon, J.T. (Alaska Div. of Geological and Geophysical Surveys, Fairbanks (USA)); Haxel, G.B. (Geological Survey, Flagstaff, AZ (USA)); Tosdal, R.M. (Geological Survey, Menlo Park, CA (USA))

1990-11-10

385

Parton shower effects on W and Z production via vector boson fusion at NLO QCD  

NASA Astrophysics Data System (ADS)

We present the implementation of electroweak Zjj and Wjj production via vector boson fusion with fully leptonic decays at NLO QCD in the P owheg framework. These processes represent an important background to Higgs searches in vector boson fusion, but they also can be seen as signal processes to study anomalous triple vector boson couplings as well as the impact of a central jet veto. Observables related to the third jet are sensitive to the parton shower which is used, a fact which is demonstrated by a comparison between P ythia, the standard angular-ordered H erwig++ shower and the new p T -ordered Dipole Shower in H erwig++.

Schissler, Franziska; Zeppenfeld, Dieter

2013-04-01

386

Top-quark charge asymmetry with a jet handle  

NASA Astrophysics Data System (ADS)

Pairs of top and antitop quarks are produced at the LHC to a large extent in association with a hard jet. We investigate the charge asymmetry in tt¯+j production in quantum chromodynamics (QCD) and with additional massive color-octet vector bosons. The total charge asymmetry at the LHC is suppressed by the large charge-symmetric background from gluon-gluon fusion. We show to what extent the asymmetry can be enhanced by suitable phase space cuts and, in particular, elaborate on the kinematics of the hard jet in the tt¯+j final state. We demonstrate that in QCD, the asymmetry amounts to 1.5% for central jets without an excessive reduction of the cross section. By applying additional kinematical cuts, the asymmetry can be enhanced to 4%, but at the cost of a strong reduction of the cross section. Massive color-octet states can generate sizeable effects in tt¯+j production, both on the charge asymmetry and on the cross section. The charge asymmetry probes both vector and axial-vector couplings to quarks. We show that massive color octets can generate asymmetries up to ±10% for moderate and up to ±30% for strong kinematical cuts to be used in experimental analyses at the LHC. Jet kinematics can be used to obtain further information about the nature of the couplings and thereby to discriminate between different models.

Berge, Stefan; Westhoff, Susanne

2012-11-01

387

Large-scale geometry of Montana thrust belt  

SciTech Connect

Regional plunge of a structural culmination in the Sawtooth Mountains, combined with seismic profiles and borehole data, show that the imbricated faults of the Montana Disturbed belt gather upward to merge into a duplex beneath a large thrust plate dominated by the Precambrian Belt Supergroup. The duplex formed after deposition of the Paleocene St. Mary River Formation. This thrust plate overlies the Lewis, Hoadley, El dorado, Steinbach, and related thrust faults and forms the main ranges of the Montana Rocky Mountains. The plate is shaped like a northeasterly tapering wedge; it is 3 to 4 km (10,000 to 13,000 ft) thick at its leading edge, but thickens to more than 25 km (15 mi) to the southwest. At its leading edge, the plate carries lower parts of the Belt supergroup, including the Greyson, Empire, and Spokane formations. These units and overlying parts of the Belt Supergroup thicken dramatically westward within the plate, and the older, very thick, metamorphosed Prichard Formation emerges along the Purcell and related anticlinoria. The plate forms a south-facing monocline along the Lewis and Clark line. The monocline is corrugated into a series of southeast-plunging en echelon folds of Late Cretaceous age and merges with the southern terminus of the Purcell anticlinorium. Along these folds, metamorphosed Belt strata of the plate plunge systematically beneath Paleozoic and Mesozoic rocks that are preserved in a regional structural depression at the foot of the monocline. Geometric constructions based on areal geology suggest that the monocline has 25 km (15 mi) of structural relief and overlies a major footwall ramp that continues northward beneath the Purcell anticlinorium. This footwall ramp corresponds to the depositional locus for the easterly tapering belt strata of the plate, suggesting a total northeasterly displacement of about 50 km (30 mi) for the plate.

Sears, J.W.; Dolberg, D.M.

1986-08-01

388

Jet Physics at CDF  

SciTech Connect

Jets have been studied by the CDF Collaboration [1] as a means of searching for new particles and interactions, testing a variety of perturbative QCD predictions, and providing input for the global parton distribution function (PDF) fits. Unless otherwise indicated below, the jets were reconstructed using a cone algorithm [2] with cone radius R = 0.7 from data taken at the Fermilab Tevatron collider in Run 2, 2001-2003, with {radical}s = 1.96 TeV. Central jets, in the pseudorapidity range relative to fixed detector coordinates 0.1 < |{eta}| < 0.7, are used.

Sally Seidel

2004-06-28

389

Trajectory control with continuous thrust applied to a rendezvous maneuver  

NASA Astrophysics Data System (ADS)

A rendezvous mission can be divided into the following phases: launch, phasing, far range rendezvous, close range rendezvous and mating (docking or berthing). This paper aims to present a close range rendezvous with closed loop controlled straight line trajectory. The approaching is executed on V-bar axis. A PID controller and continuous thrust are used to eliminate the residual errors in the trajectory. A comparative study about the linear and nonlinear dynamics is performed and the results showed that the linear equations become inaccurate insofar as the chaser moves away from the target.

Santos, W. G.; Rocco, E. M.

2013-10-01

390

Very high thrust-to-weight rocket engines  

NASA Astrophysics Data System (ADS)

High delta-V earth-to-orbit missions have put a premium on high performance booster rocket engines. While significant improvements to specific impulse are unlikely, high thrust-to-weight design provides a promising avenue for improving mission and vehicle capabilities and margins. Several approaches can contribute to achieving such engine designs, including proper design optimization, simplification, geometry, propellant selection, and the application of advanced materials. Incorporation of the first four approaches can yield factors of about two improvements in current liquid engine designs. The utilization of emerging material capabilities could yield another factor of two improvement with the possibility of even larger gains with far-term materials and designs.

Glass, James F.; Goracke, B. David; Levack, Daniel J. H.

1998-01-01

391

Three dimensional thermal analysis of rocket thrust chambers  

SciTech Connect

A numerical model for the three dimensional thermal analysis of rocket thrust chambers and nozzles has been developed. The input to the model consists of the composition of the fuel/oxidant mixture and flow rates, chamber pressure, coolant entrance temperature and pressure, dimensions of the engine, materials and the number of nodes in different parts of the engine. The model allows for temperature variation in three dimensions: axial, radial and circumferential directions and by implementing an iterative scheme, it provides nodal temperature distribution, rates of heat transfer, hot gas and coolant thermal and transport properties.

Naraghi, M.H.N.; Armstrong, E.S.

1988-06-01

392

Time of initial thrusting in the Sevier orogenic belt, Idaho-Wyoming and Utah  

NASA Astrophysics Data System (ADS)

Reexamination of the distribution of fossils found in the earliest preserved synorogenic conglomerates within the Sevier thrust belt suggests that initial thrust movement may be no older than Aptian age. This interpretation is corroborated by subsidence analyses of sedimentary sequences lying within and east of the Idaho-Wyoming and Utah thrust belts. A major episode of middle Cretaceous (Aptian Cenomanian) subsidence is interpreted as recording the initiation of thrust loading deformation in the adjacent Sevier orogenic belt. An earlier subsidence event took place during Middle Jurassic time, more than 30 m.y. prior to the Cretaceous event, and may be the result of tectonic events to the west that are unrelated to thrust deformation in the Idaho-Wyoming and Utah thrust belts. We find no verifiable evidence to support previous interpretations that Sevier belt deformation and uplift began in Late Jurassic time.

Heller, P. L.; Bowdler, S. S.; Chambers, H. P.; Coogan, J. C.; Hagen, E. S.; Shuster, M. W.; Winslow, N. S.; Lawton, T. F.

1986-05-01

393

Thrust faults and related structures in the crater floor of Mount St. Helens volcano, Washington  

USGS Publications Warehouse

A lava dome was built in the crater of Mount St. Helens by intermittent intrusion and extrusion of dacite lava between 1980 and 1986. Spectacular ground deformation was associated with the dome-building events and included the development of a system of radial cracks and tangential thrust faults in the surrounding crater floor. These cracks and thrusts, best developed and studied in 1981-1982, formed first and, as some evolved into strike-slip tear faults, influenced the subsequent geometry of thrusting. Once faulting began, deformation was localized near the thrust scarps and their bounding tear faults. The magnitude of displacements systematically increased before extrusions, whereas the azimuth and inclination of displacements remained relatively constant. The thrust-fault scarps were bulbous in profile, lobate in plan, and steepened during continued fault movement. The hanging walls of each thrust were increasingly disrupted as cumulative fault slip increased. -from Authors

Chadwick, Jr, W. W.; Swanson, D. A.

1989-01-01

394

Direct thrust measurements and modelling of a radio-frequency expanding plasma thruster  

NASA Astrophysics Data System (ADS)

It is shown analytically that the thrust from a simple plasma thruster (in the absence of a magnetic field) is given by the maximum upstream electron pressure, even if the plasma diverges downstream. Direct thrust measurements of a thruster are then performed using a pendulum thrust balance and a laser displacement sensor. A maximum thrust of about 2 mN is obtained at 700 W for a thruster length of 17.5 cm and a flow rate of 0.9 mg s-1, while a larger thrust of 4 mN is obtained at a similar power for a length of 9.5 cm and a flow rate of 1.65 mg s-1. The measured thrusts are in good agreement with the maximum upstream electron pressure found from measurements of the plasma parameters and in fair agreement with a simple global approach used to model the thruster.

Lafleur, T.; Takahashi, K.; Charles, C.; Boswell, R. W.

2011-08-01

395

Crustal scale geometry of the Zagros fold–thrust belt, Iran  

Microsoft Academic Search

Balanced cross-sections across the Zagros fold–thrust belt in Iran are used to analyze the geometry of deformation within the sedimentary cover rocks, and to test the hypothesis of basement involved thrusting throughout the fold–thrust belt. Although the Zagros deformation front is a relatively rectilinear feature, the sinuous map-view morphology of the mountain front is a result of a 6 km

Nadine McQuarrie

2004-01-01

396

Structural evidence for northeastward movement on the Chocolate Mountains Thrust, southeasternmost California  

NASA Astrophysics Data System (ADS)

The Late Cretaceous Chocolate Mountains thrust of southeastern California and southwestern Arizona places a block of Proterozoic and Mesozoic continental crust over the late Mesozoic continental margin oceanic sedimentary and volcanic rocks of the regionally distinctive Orocopia Schist. The Chocolate Mountains thrust is interpreted as a thrust (burial, subduction) fault rather than a low-angle normal (exhumation, unroofing, uplift) fault. An important parameter required to understand the tectonic significance of the Chocolate Mountains and related thrusts is their sense of movement. The Chocolate Mountains thrust zone contains sparse to locally abundant mesoscopic asymmetric folds. Fabric relations, supported by regional geologic evidence, indicate that these folds are an integral part of and coeval with the thrust zone. On a lower hemisphere equal-area plot representing the orientation and sense of asymmetry of 80 thrust zone folds from 36 localities, spread over an area 60 by 10 km, Z folds plot northwest of and S folds plot southeast of a northeast-southwest striking vertical plane of overall monoclinic symmetry. The only sense of movement consistent with the collective asymmetry of the thrust zone folds is top to the northeast. Asymmetric microstructures studied at several localities also indicate top to the northeast movement. Paleomagnetic data suggest that the original sense of thrusting, prior to Neogene vertical axis tectonic rotation related to the San Andreas fault system, was northward. The essential point is that movement of the upper plate of the Chocolate Mountains thrust evidently was continentward. Continentward thrusting suggests a tectonic scenario in which an insular or peninsular microcontinental fragment collided with mainland southern California. The suture predicted by this model is elusive; but the Chocolate Mountains thrust and underlying Orocopia Schist themselves may represent the suture, at the present level of exposure. Alternative tectonic models involving subduction of the Orocopia Schist eastward beneath continental southern California circumvent the suture problem but are presently not supported by any direct structural evidence.

Dillon, John T.; Haxel, Gordon B.; Tosdal, Richard M.

1990-11-01

397

Controls on the architecture of the Sierra Madre Oriental fold-thrust belt  

Microsoft Academic Search

Geologic mapping and structural analysis of east-central Mexico were conducted to assess the architecture and structural evolution of the SMO fold-thrust belt. We present a regional map that synthesizes our results from the hinterland to foreland of the SMO fold-thrust belt over a distance of 180 km. Our results show that several regional east-directed thrust faults step-up structurally via flats

M. A. Murphy

2007-01-01

398

Direct Optimization of Low-thrust Many-revolution Earth-orbit Transfers  

Microsoft Academic Search

Low-thrust Earth-orbit transfers with 10?5-order thrust-to-weight ratios involve a large number of orbital revolutions which poses a real challenge to trajectory optimization. This article develops a direct method to optimize minimum-time low-thrust many-revolution Earth-orbit transfers. A parameterized control law in each orbit, in the form of the true optimal control, is proposed, and the time history of the parameters governing

Gao Yang

2009-01-01

399

Jets in hadronic reactions  

SciTech Connect

Recent experimental data on the properties of jets in hadronic reactions are reviewed and compared with theoretical expectations. Jets are clearly established as the dominant process for high E/sub T/ events in hadronic reactions. The cross section and the other properties of these events are in qualitative and even semiquantitative agreement with expectations based on perturbative QCD. However, we can not yet make precise tests of QCD, primarily because there are substantial uncertainties in the theoretical calculations. 45 references. (WHK)

Paige, F.E.

1983-01-01

400

Simulations of Pulse Detonation Engines with MHD Thrust Augmentation  

NASA Astrophysics Data System (ADS)

Pulse detonation rocket engines (PDREs) have received significant attention in recent years due to their potentially superior performance over constant-pressure engines. Yet unsteady chamber pressures cause the PDRE flow to be either over-expanded or under-expanded for the majority of the cycle, with substantial performance loss in atmospheric flight applications. The present computational studies examine the potential benefits of using magneto-hydrodynamic (MHD) thrust augmentation by extracting energy via a generator in the PDRE nozzle and applying it to a separate, secondary stream. In the present studies, which involve both transient quasi-1D and 2D numerical simulations, the energy extracted from the nozzle flow is directly applied to a by-pass air stream through an MHD accelerator. The air stream is first shocked by the under-expanded nozzle flow and raised to high temperature, allowing thermal ionization. The specific conditions for thrust augmentation are examined. Alternative configurations utilizing a magnetic piston in the PDRE chamber are also explored. Results show potential performance gains but with significant challenges, depending on the operating and flight conditions.

Zeineh, Christopher; Roth, Timothy; Cole, Lord; Karagozian, Ann; Cambier, Jean-Luc

2008-11-01

401

Compact and High Thrust Air Turbo Ram Engine  

NASA Astrophysics Data System (ADS)

The Air Turbo Ramjet (ATR) is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds and therefore the ATR is an attractive propulsion system for the wide operation range (e.g. Mach 0 to Mach 4). The ATR can provide a higher specific impulse than a solid fuel rocket engine and a higher thrust per frontal area than a turbojet engine. The major ATR components are the inlet, fan (compressor), turbine, gas generator, combustor and exhaust nozzle. In the ATR, the turbine drive gas is generated by a decomposed liquid or solid fuel gas generator. In order to carry heavier payloads and to attain shorter flight time, the compact and high thrust engine is required. In this study, the ram combustor with the double-staged flameholders and the fan with tandem blade were introduced to shorten the engine length and to increase the fan pressure ratio, respectively. Furthermore, the engine testing was carried out on sea level static condition to confirm the engine component integration technologies for the ATR propulsion system.

Hasegawa, Hiroaki; Kitahara, Kazuki; Inukai, Yasuo

402

Preloading of the thrust phase in cross-country skiing.  

PubMed

Based on the assumption that the stretch-shortening cycle is a natural way of muscle function, the occurrence of such a cycle was investigated in a diagonal technique of cross-country skiing. Cinematographic, special force platform, and telemetered EMG techniques were employed. The four subjects studied were all elite international level cross-country skiers, and the measurements were taken either under world championship conditions (cinematography) or during special test situations outdoors (EMG, force platform, and cinematography). The skiing was performed on the fixed uphill course (competition) and on the variable uphill tracks (2.5 degrees-11 degrees). The latter condition allowed mounting of a special long force platform system under the track. The results indicated that the leg kick phase is preceded by a typical unweighting phase, which is followed by braking and propulsion phases. Angular velocity curves of the hip, knee, and ankle joints revealed indirectly the segmental occurrence of the stretch-shortening cycle. Similar phenomena could be identified for the elbow joint during the pole plant and thrust phases. On a steep uphill track, the muscle activation pattern and the ground reaction forces resembled in many instances those of slow level running. Based on the results, a model was suggested to describe how the preloading of the leg thrust phase takes place as a sequential flow from one joint to another. PMID:3583520

Komi, P V; Norman, R W

1987-03-01

403

Measurement of the strong coupling ?S from four-jet observables in e+e- annihilation  

NASA Astrophysics Data System (ADS)

Data from e+e- annihilation into hadrons at centre-of-mass energies between 91 GeV and 209 GeV collected with the OPAL detector at LEP, are used to study the four-jet rate as a function of the Durham algorithm resolution parameter ycut. The four-jet rate is compared to next-to-leading order calculations that include the resummation of large logarithms. The strong coupling measured from the four-jet rate is ?_{text{S}(M_{text{Z}^0})}=0.1182±0.0003(text{stat.})±0.0015(text{exp.}) ±0.0011(text{had.})±0.0012(text{scale})±0.0013(text{mass}), in agreement with the world average. Next-to-leading order fits to the D-parameter and thrust minor event-shape observables are also performed for the first time. We find consistent results, but with significantly larger theoretical uncertainties.

Abbiendi, G.; Ainsley, C.; Åkesson, P. F.; Alexander, G.; Anagnostou, G.; Anderson, K. J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R. J.; Batley, R. J.; Bechtle, P.; Behnke, T.; Bell, K. W.; Bell, P. J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, R. M.; Burckhart, H. J.; Campana, S.; Capiluppi, P.; Carnegie, R. K.; Carter, A. A.; Carter, J. R.; Chang, C. Y.; Charlton, D. G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; de Roeck, A.; de Wolf, E. A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I. P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, J. W.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, M.; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwé, M.; Günther, P. O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G. G.; Harel, A.; Hauschild, M.; Hawkes, C. M.; Hawkings, R.; Hemingway, R. J.; Herten, G.; Heuer, R. D.; Hill, J. C.; Horváth, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T. R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R. K.; Kellogg, R. G.; Kennedy, B. W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Krämer, T.; Krasznahorkay, A.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G. D.; Landsman, H.; Lanske, D.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S. L.; Loebinger, F. K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A. J.; Mashimo, T.; Mättig, P.; McKenna, J.; McPherson, R. A.; Meijers, F.; Menges, W.; Merritt, F. S.; Mes, H.; Meyer, N.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D. J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H. A.; Nisius, R.; O'Neale, S. W.; Oh, A.; Oreglia, M. J.; Orito, S.; Pahl, C.; Pásztor, G.; Pater, J. R.; Pilcher, J. E.; Pinfold, J.; Plane, D. E.; Pooth, O.; Przybycie?, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J. M.; Rossi, A. M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E. K. G.; Schaile, A. D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schörner-Sadenius, T.; Schröder, M.; Schumacher, M.; Seuster, R.; Shears, T. G.; Shen, B. C.; Sherwood, P.; Skuja, A.; Smith, A. M.; Sobie, R.; Söldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, D.; Ströhmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M. A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trócsányi, Z.; Tsur, E.; Turner-Watson, M. F.; Ueda, I.; Ujvári, B.; Vollmer, C. F.; Vannerem, P.; Vértesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C. P.; Ward, D. R.; Watkins, P. M.; Watson, A. T.; Watson, N. K.; Wells, P. S.; Wengler, T.; Wermes, N.; Wilson, G. W.; Wilson, J. A.; Wolf, G.; Wyatt, T. R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, L.

2006-08-01

404

Coiling of viscous jets  

NASA Astrophysics Data System (ADS)

A stream of honey poured from a sufficient height forms a series of helical coils as it approaches a piece of toast. I have studied the dynamics of this instability using an asymptotic theory for a thin inertia-free viscous jet that deforms under the action of gravity and surface tension. The jet's shape is described by the radius of its cross-section and the curvature and torsion of its axis, as functions of arclength and time. Such a jet can experience four distinct modes of deformation: stretching/shortening; bending in the local osculating plane; bending out of the osculating plane; and twisting. The instantaneous response of the jet to applied loads is described by a twelfth-order system of coupled ordinary differential equations, comprising the equations of global (integrated) force and moment balance together with appropriate constitutive relations for the stress resultants and bending moments. The temporal evolution of the jet's radius and axial shape is described by additional kinematic equations of hyperbolic type. The equations are solved numerically using a relaxation method for the instantaneous response and a staggered leapfrog scheme for the time evolution. The critical feature of the dynamics is a bifurcation from a state of ``forced'' coiling in which buoyancy forces are negligible to one of ``free'' coiling in which those forces are dominant. I will present scaling laws for the coiling frequency in both regimes, as functions of the pouring height, the flow rate, the initial jet radius, and the fluid properties.

Ribe, Neil

2002-11-01

405

The elusive optical jets  

SciTech Connect

Imaging observations in the U band of eight radio galaxies are presented. No optical counter-part to the radio jets are found. For the three radio galaxies 3C 147, 3C 279, and 3C 433, it is shown that the radio to optical spectral index of the jet is significantly higher than the typical values found in the three best-known opticals jets (M87, 3C 273, and 3C 66B). It is concluded that the cutoff frequencies are lower than 10 to the 14th Hz in these cases. For the 3C 31 jet, data are consistent with the radio to optical spectral index being comparable to the typical values. This result is in contradiction with the detection of the optical jet in the B band by Butcher et al. (1980). Finally, the lower limit on the radio to optical spectral index obtained for the four other radio jets of the sample is still consistent with the typical values. 35 refs.

Fraix-Burnet, D.; Nieto, J.L.; Golombek, D.; Macchetto, F.; Lelievre, G. (Observatoire Midi-Pyrenees, Toulouse (France) Space Telescope Science Institute, Baltimore, MD (USA) Paris Observatoire (France))

1991-01-01

406

Vector-valued wavelets and vector filter banks  

Microsoft Academic Search

In this paper, we introduce vector-valued multiresolution analysis and vector-valued wavelets for vector-valued signal spaces. We construct vector-valued wavelets by using paraunitary vector filter bank theory. In particular, we construct vector-valued Meyer wavelets that are band-limited. We classify and construct vector-valued wavelets with sampling property. As an application of vector-valued wavelets, multiwavelets can be constructed from vector-valued wavelets. We show

Xiang-Gen Xia; B. W. Suter

1996-01-01

407

Vector Addition Patterns Model  

NSDL National Science Digital Library

The Vector Addition Patterns model illustrates the tail-to-tip method of adding vectors. The table at the bottom shows the components and lengths of the vectors. You can also rotate the vectors and trace out some interesting patterns. The Vector Addition Patterns model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_addition_patterns.jar file will run the program if Java is installed.

Duffy, Andrew

2010-05-02

408

Physics of Coanda jet detachment at high-pressure ratio  

NASA Astrophysics Data System (ADS)

Experimental measurements of surface pressure for an underexpanded two-dimensional supersonic Coanda flow with static conditions exterior to the jet flow was obtained for a fixed slot height to a radius ratio of 0.04. The data demonstrate that an oblique shock forms near the jet exit plane which vectors the jet flow from the curved surface at a pressure ratio of 7.6. The jet detachment occurs at a pressure ratio which is a function of the ratio of slot height to cylinder radius. An increase in the pressure ratio to 11.5 before jet detachment has been demonstrated by the translation of the upper wall providing for a converging-diverging geometry. The physics of the Coanda expansion and the jet detachment are qualitatively described using an optical schlieren system. A compressible inviscid model was derived analytically to demonstrate the variation in Mach number and surface pressure as a function of the geometric parameters with increasing pressure ratio.

Cornelius, Kenneth C.; Lucius, Gerald A.

1994-05-01

409

Contrasting strike-slip motions on thrust and normal faults: Implications for space-geodetic monitoring of surface deformation  

NASA Astrophysics Data System (ADS)

Recent GPS records of surface deformation caused by earthquakes on intra-continental dip-slip faults revealed in unprecedented detail a significant strike-slip component near the fault tips, which is markedly different for thrust and normal faults. In the hanging wall of the thrust fault ruptured during the 2003 Chengkung (Taiwan) earthquake, a divergent displacement pattern was recorded (Hsu et al., 2009). In contrast, a convergent slip pattern was observed in the hanging wall of the normal fault that produced the 2009 L'Aquila (Italy) earthquake (Cheloni et al., 2010; Serpelloni et al., 2012). Remarkably, such convergent slip patterns are also evident in field records of cumulative fault slip (e.g., Jackson et al., 1982; Roberts & Koukouvelas 1996), which underlines the coseismic origin of the cumulative slip pattern. Here we use three-dimensional numerical modeling to demonstrate that the observed fault-parallel motions are a characteristic feature of the coseismic slip pattern on normal and thrust faults (Hampel et al., in press). Modeled slip vectors converge toward the center of normal faults whereas they diverge for thrust faults, which causes contrasting fault-parallel displacements at the model surface. Our model also predicts divergent movements in normal fault footwalls, which were recorded for the first time during the L'Aquila earthquake. During the postseismic phase, viscous flow in the lower crust induces fault-parallel surface displacements, which have the same direction as the coseismic displacements but are distributed over a larger area that extends far beyond the fault tips. Hence, detecting this signal requires GPS stations in the prolongation of the fault's strike. Postseismic velocities vary over several orders of magnitude depending on the lower-crustal viscosity and may reach tens of millimeters per year for low viscosities. Our study establishes the link between coseismic and cumulative slip patterns on normal and thrust faults and emphasizes that understanding fault-parallel slip components and associated surface displacements is essential for inferring regional deformation patterns from space-geodetic and fault-slip data. References: Cheloni, D., N. D'Agostino, E. D'Anastasio, A. Avallone, S. Mantenuto, R. Giuliani, M. Mattone, S. Calcaterra, P. Gambino, D. Dominici, F. Radicioni, G. Fastellini (2010) Coseismic and initial post-seismic slip of the 2009 Mw 6.3 L'Aquila earthquake, Italy, from GPS measurements: Geophysical Journal International, 181, 1539-1546. Hampel, A., T. Li, G. Maniatis (in press) Contrasting strike-slip motions on thrust and normal faults: Implications for space-geodetic monitoring of surface deformation: Geology. Hsu, Y.-J., S.-B Yu, H.-Y. Chen (2009) Coseismic and postseismic deformation associated with the 2003 Chengkung, Taiwan, earthquake: Geophysical Journal International, 176, 420-430. Jackson, J.A., J. Gagnepain, G. Houseman, G.C.P. King, P. Papadimitriou, C. Soufleris, J. Virieux (1982) Seismicity, normal faulting, and the geomorphological development of the Gulf of Corinth (Greece): The Corinth earthquakes of February and March 1981: Earth and Planetary Science Letters, 57, 377-397. Roberts, G.P., I. Koukouvelas (1996) Structural and seismological segmentation of the Gulf of Corinth fault system: Implications for models of fault growth: Annali di Geofisica, 39, 619-646. Serpelloni, E., L. Anderlini, M.E. Belardinelli (2012) Fault geometry, coseismic-slip distribution and Coulomb stress change associated with the 2009 April 6, Mw 6.3, L'Aquila earthquake from inversion of GPS displacements: Geophysical Journal International, 188, 473-489.

Hampel, Andrea; Li, Tao; Maniatis, Georgios

2013-04-01

410

Vector Components Model  

NSDL National Science Digital Library

The Vector Components model allows the user to split a vector into its components, and practice finding the magnitude and direction of a vector if you know the components. In the "Find components" mode, you are given the magnitude and direction of the vector, and your goal is to find the x-component and the y-component of the vector. In the "Find magnitude and direction" mode, you are given the two components, and you need to find the magnitude and direction of the vector. The Vector Components was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_components.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-27

411

An airborne jet train that flies on a soft porous track  

NASA Astrophysics Data System (ADS)

This paper explores the quantitative feasibility of developing an airborne jet train that flies on a soft porous track within centimeters of the earth's surface at speeds approaching current commercial jet aircraft. The jet train employs a lift mechanism first proposed in Feng & Weinbaum (2000) J. Fluid Mech. 422:282 and a nearly frictionless track suggested in Wu et al. (2004) Phys. Rev. Lett. 93(19):194501. Using an asymptotic analysis for large values of the permeability parameter H/Kp, where H is the porous layer thickness and Kp the Darcy permeability, we first show that it is possible to support a 70 metric ton jet train carrying 200 passengers on a confined porous material if its Kp is approximately 5 x 10-9 m^2. For this Kp one finds that the tilt of the planform is < 0.1 degrees and the lift-off velocity is < 5 m/s. Compression tests on a fiber-fill material with these properties show that the fibers contribute < 0.2 percent of the total lift and hence the friction force of the fiber phase is negligible. Using jet engines of 10,000 lbf thrust, about 1/5 that of a 200 passenger jet aircraft, one is able to obtain a cruising velocity approaching 700 km/hr. This would allow for huge fuel savings, especially on short flights where much of the energy is used to climb to altitude and overcoming lift induced drag.

Mirbod, Parisa; Andreopoulos, Yiannis; Weinbaum, Sheldon

2008-11-01

412

Flow structures of gaseous jets injected into water for underwater propulsion  

NASA Astrophysics Data System (ADS)

Gaseous jets injected into water are typically found in underwater propulsion, and the flow is essentially unsteady and turbulent. Additionally, the high water-to-gas density ratio can result in complicated flow structures; hence measuring the flow structures numerically and experimentally remains a challenge. To investigate the performance of the underwater propulsion, this paper uses detailed Navier-Stokes flow computations to elucidate the gas-water interactions under the framework of the volume of fluid (VOF) model. Furthermore, these computations take the fluid compressibility, viscosity, and energy transfer into consideration. This paper compares the numerical results and experimental data, showing that phenomena including expansion, bulge, necking/breaking, and back-attack are highlighted in the jet process. The resulting analysis indicates that the pressure difference on the rear and front surfaces of the propulsion system can generate an additional thrust. The strong and oscillatory thrust of the underwater propulsion system is caused by the intermittent pulses of the back pressure and the nozzle exit pressure. As a result, the total thrust in underwater propulsion is not only determined by the nozzle geometry but also by the flow structures and associated pressure distributions.

Tang, Jia-Ning; Wang, Ning-Fei; Shyy, Wei

2011-08-01

413

Lithospheric Scale Deformation in Mega-thrust Subduction Zones  

NASA Astrophysics Data System (ADS)

Although the general plate tectonic model of subduction zone deformation and its relationship to the earthquake cycle for mega-thrust earthquakes is well known, there is neither consistency in such descriptions nor compatibility among seismological, geodetic, and geologic frameworks for such events. In particular in most seismologic studies of mega-thrust earthquakes there is an implicit assumption that the co-seismic slip is essentially symmetric across the fault surface - that is both the upper and lower plates moved equal amounts (but in opposite directions) during the rupture. Implicit in many geologic studies along convergent margins is the assumption that most permanent deformation is within the upper plate and the subducting slab basically transits the seismogenic zone with little permanent deformation. This perspective serves as the framework for many animations of subduction zone tectonics. Two subduction zone locales, the Kuriles and Solomon Islands, that have hosted recent Mw 8+ earthquakes demonstrate two end-member styles of subduction zone processes neither consistent with the conventional view. The November 2006 (thrust) and January 2007 (normal) earthquake pair in the Kuriles provide an opportunity to quantify the deformation within the subducting Pacific slab during the interseismic period. Based on the correspondence in slip during these events, we are able to both estimate the deformation (dominantly in the subducting slab and not in the overriding plate) and place a constraint on the static frictional strength of the megathrust interface of approximately 2-5 MPa. The 2007 Solomon Island Mw 8+ earthquake shows a distinctly different pattern of interseismic deformation. During this event, the propagating rupture traversed an active transform plate boundary between the separately subducting Australia and Solomon Sea plates. We interpret this to represent a situation in which interseismic deformation is primarily in the upper (Pacific) plate allowing the rupture to jump the fundamental barrier of a plate boundary. This is also compatible with limited GPS data available for the Australia plate near the trench indicating unimpeded subduction of Australia and thus little internal deformation of the subducting slab. These two subduction regimes indicate that there is likely a full continuum in how deformation is accommodated during subduction, and implies that attempts to determine the megathrust (and associated tsunami) potential of subduction zones using observations of upper-plate deformation is problematic.

Furlong, K. P.; Ammon, C.; Lay, T.

2008-12-01

414

Measurement of Z/gamma*+jet+X angular distributions in p anti-p collisions at s**(1/2) = 1.96.TeV  

SciTech Connect

We present the first measurements at a hadron collider of differential cross sections for Z/{gamma}* + jet + X production in {Delta}{phi}(Z, jet), |{Delta}y(Z, jet)| and |y{sub boost}(Z + jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.

Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; /Oklahoma U.; Abolins, Maris A.; /Michigan State U.; Acharya, Bannanje Sripath; /Tata Inst.; Adams, Mark Raymond; /Illinois U., Chicago; Adams, Todd; /Florida State U.; Aguilo, Ernest; /Alberta U. /Simon Fraser U. /York U., Canada /McGill U.; Ahsan, Mahsana; /Kansas State U.; Alexeev, Guennadi D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls /Northeastern U.

2009-07-01

415

B-jets and z + b-jets at CDF  

SciTech Connect

The authors present CDF cross-section measurements for the inclusive production of b jets and the production of b jets in association with a Z{sup 0} boson. Both measurements are in reasonable agreement with NLO QCD predictions.

Jeans, Daniel; /Rome U.

2006-06-01

416

Multi-wavelength and Stereoscopic observations of a coronal jet supporting the emerging flux reconnection model  

NASA Astrophysics Data System (ADS)

We have investigated a coronal jet near the limb on 2010 June 27 by Hinode/X-Ray Telescope (XRT), EUV Imaging Spectrograph (EIS), Solar Optical Telescope (SOT), SDO/Atmospheric Imaging Assembly (AIA), and STEREO. From EUV (AIA and EIS) and soft X-ray (XRT) images we identify the erupting jet feature in cool and hot temperatures. It is noted that there was a small loop eruption at the low temperature from the SOT observation before the jet eruption. Using the high temporal and multi wavelength AIA images, we found that the hot jet preceded its associated cool jet. The jet also shows the helical-like structures during the rising period. According to the spectroscopic analysis, the jet structure changes from blue shift to red one with time, implying the helical structure of the jet. The STEREO observation, which enables us to observe this jet on the disk, shows that there was a dim loop associated with the jet. Comparing observations from the AIA and STEREO, the dim loop corresponds to the jet structure which implies the heated loop. Considering that the structure of its associated active region seen in STEREO is similar to that in AIA observed 5 days before, we compared the jet morphology on the limb with the magnetic fields extrapolated from a HMI vector magnetogram observed on the disk. Interestingly, the comparison also shows that the open field corresponds to the jet which is seen as the dim loop in STEREO. Our observations (XRT, SDO, SOT, and STEREO) are well consistent with the numerical simulation of the emerging flux reconnection model predicted.

Lee, K.; Innes, D.; Moon, Y.; Shibata, K.

2011-12-01

417

Rhotrix Vector Spaces  

ERIC Educational Resources Information Center

|By rhotrix we understand an object that lies in some way between (n x n)-dimensional matrices and (2n - 1) x (2n - 1)-dimensional matrices. Representation of vectors in rhotrices is different from the representation of vectors in matrices. A number of vector spaces in matrices and their properties are known. On the other hand, little seems to be…

Aminu, Abdulhadi

2010-01-01

418

Nonviral Vector Systems  

Microsoft Academic Search

Gene therapy requires efficient vectors for delivering therapeutic genes. Advances in developments of nonviral vectors have\\u000a been established for improving the efficiency of gene delivery. This chapter describes different nonviral methods as well\\u000a as their applications. Some new directions in developing nonviral vectors are also discussed.

Pui-yan Lee; Leaf Huang

419

Asymptotic Code Vector Density in Topographic Vector Quantizers.  

National Technical Information Service (NTIS)

A noise robust vector quantizer model is used to derive expressions for the asymptotic code vector density in various types of topographic vector quantizers. A topographic vector quantizer is not identical to a standard (i.e., Kohonen) topographic mapping...

S. P. Luttrell

1990-01-01

420

Palinspastic reconstruction of the Alpine thrust belt at the Alpine-Carpathian transition - A geological Sudoku  

NASA Astrophysics Data System (ADS)

The palinspastic reconstruction of the Austroalpine thrust belt is part of the project Karpatian Tectonics, which is funded by OMV Austria. The objective is to reconstruct the evolution of the thrust belt through the Early to Middle Miocene in order to obtain information on the palaeogeographic position of the Northern Calcareous Alps (NCA) in the region of the present Vienna Basin. A particular goal of the study is to constrain the position of reservoir rocks within the Rhenodanubic Flysch units and the NCA with respect to the autochthonous Malmian source rocks overlying the European basement below the Alpine-Carpathian thrust wedge, and to constrain the burial history of these source rocks. Reconstruction uses regional 2D seismic lines crossing from the European foreland into the fold-thrust belt, 3D seismic data covering the external thrust sheets, and lithostratigraphic data from a total of 51 selected wells, which were drilled and provided by OMV Austria. The main criterion, whether a well was suitable for palinspastic reconstruction or not, was its penetration of Alpine thrust sheets down to the Autochthonous Molasse of the foreland. Additional wells, which do not penetrate the entire Alpine thrust complex but include the Allochthonous Molasse or the external Alpine-Carpathian nappes (Waschberg and Roseldorf thrust unit, Rhenodanubic Flysch nappes) in their well path, were also taken into account. The well data in particular comprise stratigraphic information on the youngest overthrust sediments of the different thrust units and the underlying Autochthonous foreland Molasse. These data allow constraining the timing of thrust events in the allochthonous thrust units and overthrusting of the Autochthonous Molasse. In the particular case of overthrust Autochthonous Molasse, additionally to the timing of overthrusting, which can be derived from the youngest overthrust sediments, the palaeogeographic position of the Alpine Carpathian thrust front could directly be inferred from well data for the specific time period. By further utilization of geological maps, geological cross sections and two regional c. 80 km long composite 2D seismic sections through the external Alpine thrusts, the positions of major thrusts could be approximated for five time slices. This procedure was applied for the front of the allochthonous Molasse units, the floor thrust of the Roseldorf thrust unit, the Waschberg thrust unit and the frontal thrusts of the Rhenodanubic Flysch and the NCA. In addition, several out-of-sequence thrusts within the Waschberg unit, the Molasse unit, the Rhenodanubic Flysch and the Calcareous Alps (floor thrust of the NCA and two internal thrusts) were taken into account. The reconstruction results in 5 palinspastic maps for the time slices early Egerian (25 Ma), early Eggenburgian (20 Ma), Ottnangian (17.5 Ma), Lower Karpatian (16.5 Ma) and the Karpatian/ Badenian stage boundary (16 Ma). Convergence rates, which were calculated for the four intervening time intervals, range from about 3 mm/yr to 5 mm/yr. These values compare well with estimated convergence rates reconstructed for the Miocene in the western Eastern Alps (Schmid et al., 1996), as well as with plate tectonic constraints on Tertiary convergence rates (Dewey et al., 1989). Dewey, J., Helman, M.L., Turco, E., Hutton, D.H.W.&Knott, S.D., 1989. Kinematics of the western Mediterranean, in: N.P. Coward, D. Dietrich & R.G. Park (eds.), Alpine Tectonics, Geol. Soc. Spec. Publ., 45: 265-283. Schmid, S.M., Pfiffner, O.A., Frotzheim, N., Schönborn, G. & Kissling, E., 1996. Geophysical-geological transect and tectonic evolution of the Swiss-Italian Alps. Tectonics, 15: 1036-1064.

Beidinger, A.; Decker, K.; Zamolyi, A.; Hölzel, M.; Hoprich, M.; Strauss, P.

2009-04-01

421

Differential displacement and rotation in thrust fronts: A magnetic, calcite twinning and palinspastic study of the Jones Valley thrust, Alabama, US Appalachians  

Microsoft Academic Search

To test whether a displacement gradient along a curved fault structure requires rotation, we studied the northeast-striking, northwest-verging, large-displacement Jones Valley thrust fault of the Appalachian thrust belt in Alabama. Paleomagnetism, anisotropy of magnetic susceptibility (AMS) and calcite twinning analysis, complemented by balanced cross-sections, were used to evaluate the presence and magnitude of any rotation. Remanence directions from the Silurian

James S. Hnat; Ben A. van der Pluijm; Rob Van der Voo; William A. Thomas

2008-01-01

422

Relative timing of calcite twinning strain and fold-thrust belt development; Hudson Valley fold-thrust belt, New York, U.S.A  

Microsoft Academic Search

Coarse-grained limestone samples were collected across the Hudson Valley Fold-Thrust Belt with the aim of determining the temporal and spatial relationship between calcite twinning strain and fold-thrust belt development. The majority of the samples have well defined oblate strain ellipsoids with the maximum shortening axes (e3) perpendicular to bedding strike, and e3 magnitudes that range from ? 1.5% to 6.5%.

John H. Harris; Ben A. Van Der Pluijm

1998-01-01

423

Coseismic fault-related fold model, growth structure, and the historic multisegment blind thrust earthquake on the basement-involved Yoro thrust, central Japan  

NASA Astrophysics Data System (ADS)

We use high-resolution seismic reflection profiles, boring transects, and mapping of fold scarps that deform late Quaternary and Holocene sediments to define the kinematic evolution, subsurface geometry, coseismic behavior, and fault slip rates for an active, basement-involved blind thrust system in central Japan. Coseismic fold scarps on the Yoro basement-involved fold are defined by narrow fold limbs and angular hinges on seismic profiles, suggesting that at least 3.9 km of fault slip is consumed by wedge thrust folding in the upper 10 km of the crust. The close coincidence and kinematic link between folded horizons and the underlying thrust geometry indicate that the Yoro basement-involved fold has accommodated slip at an average rate of 3.2 ± 0.1 mm/yr on a shallowly west dipping thrust fault since early Pleistocene time. Past large-magnitude earthquakes, including an historic M˜7.7 event in A.D. 1586 that occurred on the Yoro blind thrust, are shown to have produced discrete folding by curved hinge kink band migration above the eastward propagating tip of the wedge thrust. Coseismic fold scarps formed during the A.D. 1586 earthquake can be traced along the en echelon active folds that extend for at least 60 km, in spite of different styles of folding along the apparently hard-linked Nobi-Ise blind thrust system. We thus emphasize the importance of this multisegment earthquake rupture across these structures and the potential risk for similar future events in en echelon active fold and thrust belts.

Ishiyama, Tatsuya; Mueller, Karl; Sato, Hiroshi; Togo, Masami

2007-03-01

424

1st ACT global trajectory optimisation competition: Results found at the Jet Propulsion Laboratory  

NASA Astrophysics Data System (ADS)

Results obtained at the Jet Propulsion Laboratory for the 1st ACT global trajectory optimisation competition are presented and the methods used to obtain them are described. The search for the globally optimal, low-thrust, gravity-assist trajectory for maximally deflecting an asteroid is performed in two steps. The first step involves a rough global search of the global search space, which has, however, been somewhat bounded based on prior mission-design experience, intuition, and energy arguments. A shape-based method is used to represent the low-thrust arcs, while the ballistic portions are searched almost exhaustively. The second step involves local optimisation of trajectories which stand out from the rough global search. The low-thrust optimisation problem is turned into a parameter optimisation problem by approximating the continuous thrusting as a series of impulsive manoeuvres. Of the many trajectories found, three optimal trajectories are reported and compared, including the one submitted for the competition. The best one employed a double-Venus, quadruple-Earth, Jupiter Saturn Jupiter gravity-assist sequence. The trajectory submitted for the competition used one less Venus flyby and one less Earth flyby.

Petropoulos, Anastassios E.; Kowalkowski, Theresa D.; Vavrina, Matthew A.; Parcher, Daniel W.; Finlayson, Paul A.; Whiffen, Gregory J.; Sims, Jon A.

2007-11-01

425

Jet penetration in glass  

SciTech Connect

We describe a phenomenological model which accounts for the mechanical response of glass to intense impulsive loading. An important aspect of this response is the dilatancy accompanying fracture. We have also conducted a number of experiments with 38.1-mm diameter precision shaped charges to establish the performance against various targets and to allow evaluation of our model. At 3 charge diameters standoff, the data indicate that both virgin and damaged glass offer better (Bernoulli-scaled) resistance to penetration than either of 4340 steel, or 6061-T6 aluminum alloy. Time-resolved measurements indicate two distinct phases of jet penetration in glass: An initial hydrodynamic phase, and a second phase characterized by a slower penetration velocity. Our calculations show that at early time, a crater is formed around the jet and only the tip of the undisturbed jet interacts with the glass. At late time the glass has collapsed on the jet and degraded penetration continues via a disturbed and fragmented jet.

Moran, B.; Glenn, L.A.; Kusubov, A.

1991-05-01

426

Jet propulsion without inertia  

NASA Astrophysics Data System (ADS)

A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e., jetting) surfaces are considered and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number, which corresponds to the potential flow created by a source dipole at the sphere center. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increases as the body becomes more oblate and limits to approximately 162% in the case of a flat plate swimming along its axis of symmetry. Our results are discussed in the light of slime extrusion mechanisms occurring in many cyanobacteria.

Spagnolie, Saverio E.; Lauga, Eric

2010-08-01

427

Negatively buoyant starting jets  

NASA Astrophysics Data System (ADS)

The initial development of negatively buoyant jets has been investigated experimentally and numerically, focusing on the role played by gravity in the evolution of the leading vortex ring. Under the experimental conditions considered in this work, the densimetric Froude number, Fr=?jUj2/[(?0-?j)gD], which represents the ratio between the jet momentum and the buoyancy forces, emerges as the most relevant parameter characterizing the dynamics of the flow. Two different flow regimes have been observed depending on the Froude number: for sufficiently small Fr, the vortex ring generated initially is pushed radially away by gravity forces before it has time to detach from the shear layer originating at the orifice. On the other hand, when the Froude number is larger than a critical value, Fr>Frc~1, the vortex ring detaches from the injection orifice and propagates downstream into the stagnant ambient followed by a trailing jet until it eventually reaches a maximum penetration depth. In order to clarify the mechanisms leading to the transition between the two regimes, and to gain physical understanding of the formation dynamics of negatively buoyant starting jets, the total and the vortex circulation, as well as the trajectory of the vortex center, have been measured and compared to the case of neutrally buoyant jets. Finally, based on the experimental measurements and on the results of the numerical computations, a kinematic model that successfully describes the evolution of both total circulation and vortex trajectory is proposed.

Marugán-Cruz, C.; Rodríguez-Rodríguez, J.; Martínez-Bazán, C.

2009-11-01

428

Thrust Measurements in Ballistic Pendulum Ablative Laser Propulsion Experiments  

NASA Astrophysics Data System (ADS)

This paper describes a setup for thrust measurement in ablative laser propulsion experiments, based on a simple ballistic pendulum associated to an imaging system, which is being assembled at IEAv. A light aluminium pendulum holding samples is placed inside a 100 liters vacuum chamber with two optical windows: the first (in ZnSe) for the laser beam and the second (in fused quartz) for the pendulum visualization. A TEA-CO2 laser beam is focused to the samples providing ablation and transferring linear moment to the pendulum as a whole. A CCD video camera captures the oscillatory movement of the pendulum and the its trajectory is obtained by image processing. By fitting the trajectory of the pendulum to a dumped sinusoidal curve is possible to obtain the amplitude of the movement which is directly related to the momentum transfered to the sample.

Brazolin, H.; Rodrigues, N. A. S.; Minucci, M. A. S.

2008-04-01

429

Hudson Valley Fold and Thrust Belt Field Trip (Structural Geology)  

NSDL National Science Digital Library

This structural geology field trip in the Hudson Valley region reinforces class discussions about fold and thrust belts and thin-skinned tectonics. Students observed a ramp anticline over a ramp-flat geometry fault. The anticline has minor faulting and veining in the hinge zone and folding occurred by flexural slip (evident from down-dip slickenlines on bedding surfaces). Students make observations and sketches of the outcrop and take strike and dip measurements of bedding and fault surfaces. Students can also look for a very weak cleavage. Students can use attitude measurements to reinforce key principles of stereonets including plotting lines, planes, and poles and interpreting the orientation of the fold axis (or other information) from these nets.

Growdon, Martha

430

Resonant Operation of a Micro-Newton Thrust Stand  

NASA Astrophysics Data System (ADS)

A computer automated technique suitable for evaluating micro pulsed plasma thruster (uPPT) performance has been constructed and validated in the micro-Newton (micro N) force range. A swinging gate pendulum architecture oscillates with an 3 second period. Force is applied resonantly with oscillation each half period. The calibration method utilizes an electromagnet to pick up and drop masses to apply a known force in the same resonant fashion as thruster operation. The resulting equilibrium amplitudes are linearly proportional to the applied force with an intercept near zero. Thrust measurements are insensitive to short term random vibrational noise because of the resonant operation and are insensitive to long term drift because the amplitude measurements are relative, rather than absolute.

Adkison, Paul B.; Dulligan, Michael J.

2002-06-01

431

Extreme Earth tides strongly trigger shallow, thrust earthquakes  

NASA Astrophysics Data System (ADS)

We observe tidal triggering of shallow, thrust events by strong tidal stresses. Our dataset consists of the 9350 global earthquakes of M 5.5 or greater from 1977 to 2000 in the Harvard CMT catalogue. These events include 2823 reverse, 1040 normal, 3597 strike-slip, and 1890 oblique earthquakes. We examined the entire dataset and subsets of the data for correlations with Earth tides, taking into account the amplitude of tidal stress. Tidal stress calculations include both a direct solid-Earth term and an indirect ocean-loading term. Both components must be accurately determined to fully resolve tidal influences on earthquakes triggered globally. We sort the catalog by the average of the peak Coulomb stress amplitudes before and after each event, assuming a coefficient of friction of 0.6. For the 1% of events with the highest averaged peak stress, we find significant tidal correlation, with a corresponding phase near the peak stress promoting failure. The highest correlation is seen for thrust events at or above 20 km depth with peak tidal stresses above 0.14 bars. Schuster's test, used to find statistical significance of periodicity, gives a p-value of 0.68%, or in other words there is only 0.68% chance that the distribution is randomly distributed. A second test shows that the non-random distribution peaks near the peak Coulomb stress; with 39 out of 53 earthquakes (74%) occurring in half of the time of encouraging stress. A simple binomial test of significance shows that this distribution of events corresponds to a tidal correlation at the 99.96% significance level. This result demonstrates that the tides modulate the occurrence of earthquakes at stress levels similar to those observed for the triggering of shallow aftershocks by mainshock stress redistribution.

Cochran, E. S.; Vidale, J. E.; Tanaka, S.

2004-05-01

432

Influence of material properties on the drilling thrust to hardness ratio  

Microsoft Academic Search

A drilling method developed by the authors for the measurement of the hardness profile for surface heat treated steels is based on the proportionality between drilling thrust and material hardness. However, parameters other than hardness related to the material can modify the cutting thrust level. In order to study the influence of the microstructure, the ductility, the toughness and the

G. Mauvoisin; O. Bartier; R. El Abdi; A. Nayebi

2003-01-01

433

The presence of thrust-block naled after a major surge event: Kuannersuit Glacier, West Greenland  

NASA Astrophysics Data System (ADS)

Thrust-block naled in front of Kuannersuit Glacier, West Greenland, appears to have formed during the termination of a terrestrial surge event by a combination of enhanced winter runoff, rapid advance of the glacier terminus, and proglacial stress release by thrusting and stacking of naled blocks. This process is equivalent to the formation of thrust-block moraines. The thrust-block naled consists of at least seven thrust sheets, which are characterized by stratified ice with beds composed of a lower debris-rich lamina, an intermediate dispersed lamina and a top clean-ice lamina, and underlain by frozen outwash deposits. The thrust-block naled differs from basal stratified ice in the absence of internal deformation structures, a relatively low debris concentration, a clay-rich particle-size distribution and a preferential sorting of lighter minerals. The oxygen isotope composition of the thrust-block naled is indistinguishable from ?18O values from meteoric glacier ice and bulk meltwater, but different from basal stratified ice facies. The d-?D relationship indicates that thrust-block naled has been formed by freezing of successive thin layers of bulk waters with variable isotopic composition, whereas basal stratified ice has developed in a subglacial environment with regelation. This work shows that the association between proglacial naled and rapidly advancing glaciers may have significant consequences for the proglacial geomorphology and the interpretation of basal ice layers.

Yde, Jacob C.; Knudsen, N. Tvis; Larsen, Nicolaj K.; Kronborg, Christian; Nielsen, Ole B.; Heinemeier, Jan; Olsen, Jesper

434

Role of shear in development of the Helvetic fold-thrust belt of Switzerland  

Microsoft Academic Search

The geometric features of the Helvetic nappes of the Alps show intense internal deformation set up predominantly by simple shear during nappe transport. The nappes are bounded by thrusts that parallel incompetent layers and ramp upward stratigraphically across competent units in the direction of tectonic transport; stratal layering is oblique to nappe boundaries. Thrust surfaces formed after ductile shear zones

John G. Ramsay; Martin Casey; Roy Kligfield

1983-01-01

435

Combustion-Characteristic-Based Active Thrust Modulation of a Solid Rocket Motor  

Microsoft Academic Search

A new concept of thrust modulation of solid propellant rocket motor is proposed. Some propellants cannot burn at intermediate pressure, while they can burn at lower and higher pressures. When one applies such a propellant to a motor, two combustion modes or two thrust levels are attainable without any change of the nozzle configuration. In the experiments different ignition conditions

Masafumi Tanaka; Guillaume Gaspard; Katsuya Urakawa

2010-01-01

436

Application of three fault growth criteria to the Puente Hills thrust system, Los Angeles, California, USA  

Microsoft Academic Search

Three-dimensional mechanical models are used to evaluate the performance of different fault growth criteria in predicting successive growth of three échelon thrust faults similar to the segments of the Puente Hills thrust system of the Los Angeles basin, California. Four sequential Boundary Element Method models explore the growth of successive échelon faults within the system by simulating snapshots of deformation

Erik L. Olson; Michele L. Cooke

2005-01-01

437

Theoretical analysis of effects of boundary layer bleed on scramjet thrust  

NASA Astrophysics Data System (ADS)

The effects of boundary layer bleed on the scramjet thrust are studied in the present paper. A theoretical model is developed to evaluate the thrust increment and influencing factors. The thrust increment resulting from the bleed is dominated by the rise in total pressure recovery and bleed mass flow rate. The bleed mass flow rate exerts stronger impact on the engine thrust than the total pressure. According to current bleed design, it is a severe challenge for the engine to enhance its total pressure to maintain the original thrust when there is no bleeding. Furthermore, the initial total pressure recovery, fuel mass addition, combustion efficiency and area ratio of engine exit to entrance can affect the contributions of the bleeding to the thrust increment. The scramjet needs a higher rise in total pressure recovery to counteract the negative effect of bleed mass loss at higher initial total pressure recovery or larger area ratio of engine exit/entrance. More heat release results in a little lower demand on the rise in total pressure recovery for maintaining the scramjet thrust. These results will aid in understanding the fundamental mechanism of bleeding on engine thrust.

Yue, LianJie; Xu, XianKun; Chang, XinYu

2013-10-01

438

Experimental Investigation of Thermal and Hydrodynamic Effects on Radially Grooved Thrust Washer Bearings  

Microsoft Academic Search

In this study, an experimental investigation on the effects of grooves on thrust washer bearings is investigated. Eight equally sized grooves are machined about 100 ? m deep into one side of a flat-faced steel washer. This thrust washer bearing is located between a helical gear and its carrier and is tested on a test rig capable of measuring frictional

Dooroo Kim; Robert L. Jackson; Itzhak Green

2006-01-01

439

A self-acting gas thrust bearing for high-speed microrotors  

Microsoft Academic Search

Micromachines rotating at high speeds require low drag bearings with adequate load capacity and stability. Such bearings must be compatible with the capabilities of microfabrication technology. A self-acting (hydrodynamic) gas thrust bearing was designed, fabricated and tested on a silicon microturbine. Conventional thrust bearing design techniques were adapted from macroscale literature. Microbearing design charts are presented that relate bearing performance

Chee Wei Wong; Xin Zhang; Stuart A. Jacobson; Alan H. Epstein

2004-01-01

440

Thrust Control Mechanism of VTOL UAV Cyclocopter with Cycloidal Blades System  

Microsoft Academic Search

This study describes the control mechanism of a VTOL UAV cyclocopter. The cycloidal blades system (CBS), which is a thrust system of cyclocopter is composed of several blades rotating about a horizontal axis. To generate the required thrust, the pitch angles of the blades are periodically oscillated by a pitch control mechanism. And it can change both the magnitude and

Chul Yong Yun; Ill Kyung Park; In Seong Hwang; Seung Jo Kim

2005-01-01

441

Thrust Analysis of the Linear Proportional Solenoid for a Hydraulic Control Valve  

Microsoft Academic Search

The linear proportional solenoid (LPS) is an actuator for a proportional control valve used in hydraulic pressure-control devices. The LPS must have a constant thrust over a designated displacement range, and the thrust must also increase in proportion to the exciting current. This paper deals with the effect of using dither to remove hysteresis phenomena, and describes numerical solutions for

H. Yamada; H. Nakagawa; M. Yamaguchi; K. Hagiwara; Y. Dai

1994-01-01

442

Closed Loop Control System Applied to Earth-Moon Transfer Maneuver Using Continuous Thrust  

Microsoft Academic Search

This work considers the problem of controlling the trajectory during orbital transfer maneuvers, using a propulsive system capable of applying continuous thrust for a long period of time. Some non-ideality of the thrusters and their effects on the control system during the transfer orbit were analyzed. It was considered a control system in closed loop and low-thrust propulsion with high

Evandro Marconi Rocco; Helio Koiti Kuga; Antonio Prado; Eliel Wellington Marcelino

2010-01-01

443

Oceanside and Thirtymile Bank blind thrusts: Implications for earthquake hazards in coastal southern California  

Microsoft Academic Search

We define an active blind thrust system in offshore southern California that extends from Los Angeles south to the United States Mexico international border. These blind thrusts formed by tectonic inversion of Miocene extensional detachments. We attribute the 1986 Oceanside (ML 5.3) earthquake, local uplift of marine terraces, seafloor fold scarps, and observed geodetic convergence to motion on these faults.

Carlos Rivero; John H. Shaw; Karl Mueller

2000-01-01

444

Structural development and petroleum potential of the Dagestan foreland thrust belt, Terek-Caspian Basin, Russia  

SciTech Connect

The Dagestan foreland thrust belt represents a transition zone between the Terek-Caspian basin and Caucasus. Boreholes and seismic data obtained during the last decade in the course of petroleum exploration reveal considerable differences between the surface and subsurface structures of the area. The new data suggest that the allochthonous assemblage of the belt is formed mainly by stacked north-verging thrust sheets made up mostly of Mesozoic carbonates and sandstones bounded at the top and bottom by conjugate detachment surfaces. The thrust sheets are interpreted to be inserted into the clastic section of the Terek-Caspian foredeep along the base of Oligocene-early Miocene mudstones. The interpreted geometry of the thrust-belt front implies a shortening of about 20-50 km. The blind subsurface thrusts have been active since late Miocene and Holocene. The interpreted structural relationships between Mesozoic-Cenozoic stratigraphic units imply that principal thrusts were formed due to reactivation and inversion of low-angle normal faults, which were active in the Jurassic - early Miocene. Mechanical weakness and low density of the overpressured Oligocene - lower Miocene Maykop Formation aided subsurface thrusting. The new interpretation of the regional structure offers a petroleum exploration play consisting of structural traps within the buried antiformal stacks. Oil- and gas-bearing Upper Cretaceous and Upper Jurassic carbonate rocks involved in thrust sheets are considered primary prospecting targets.

Sobornov, K. (All-Russian Research Geological Oil Institute, Moscow (Russian Federation))

1994-07-01

445

Lateral Thrust and Aerodynamics Blended Control System Design Based on Variable Structure Model Following  

Microsoft Academic Search

Variable structure model following technique is applied to the synthesis of a longitudinal autopilot for a missile with lateral thrust and aerodynamics blended. Firstly, the lateral thrust and aerodynamics blended control system model and the ideal reference model are established. Secondly, a variable structure model following controller is designed, and the stability and robustness of system are analyzed. Finally, the

Yuhang Wang; Yu Yao; Kemao Ma

2006-01-01

446

Second-Order QCD Corrections to the Thrust Distribution in Electron-Positron Annihilation  

SciTech Connect

We compute the next-to-next-to-leading-order (NNLO) QCD corrections to the thrust distribution in electron-positron annihilation. The corrections turn out to be sizable, enhancing the previously known next-to-leading-order prediction by about 15%. Inclusion of the NNLO corrections significantly reduces the theoretical renormalization scale uncertainty on the prediction of the thrust distribution.

Gehrmann-De Ridder, A. [Institute for Theoretical Physics, ETH, CH-8093 Zurich (Switzerland); Gehrmann, T. [Institut fuer Theoretische Physik, Universitaet Zuerich, CH-8057 Zurich (Switzerland); Glover, E. W. N. [Institute of Particle Physics Phenomenology, Department of Physics, University of Durham, Durham, DH1 3LE (United Kingdom); Heinrich, G. [School of Physics, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)

2007-09-28

447

An early pliocene thermal disturbance of the main central thrust, central nepal: implications for himalayan tectonics  

Microsoft Academic Search

Since the beginning of the collision betwee India and Asia at about 50 Ma, the convergence in the Himalaya has largely been taken up along major thrust zones. In this study, samples of the Lesser Himalaya Formations, up to 10 km below the Main Central Thrust (MCT), and the Greater Himalaya Sequence, up to 12 km above the MCT, have

Peter Copeland; T. Mark Harrison; Kip V. Hodges; Patricia Mauéejol; Patrick Le Fort; Arnaud Pecher

1991-01-01

448

Structural evidence for northeastward movement on the Chocolate Mountains Thrust, southeasternmost California  

USGS Publications Warehouse

The Late Cretaceous Chocolate Mountains Thrust of southeastern California and southwestern Arizona places a block of Proterozoic and Mesozoic continental crust over the late Mesozoic continental margin oceanic sedimentary and volcanic rocks of the Orocopia Schist. The Chocolate Mountains Thrust is interpreted as a thrust (burial, subduction) fault rather than a low-angle normal fault. An important parameter required to understand the tectonic significance of the Chocolate Mountains and related thrusts is their sense of movement. The only sense of movement consistent with collective asymmetry of the thrust zone folds is top to the northeast. Asymmetric microstructures studied at several localities also indicate top to the northeast movement. Paleomagnetic data suggest that the original sense of thrusting, prior to Neogene vertical axis tectonic rotation related to the San Andreas fault system, was northward. Movement of the upper plate of the chocolate Mountains thrust evidently was continentward. Continentward thrusting suggests a tectonic scenario in which an insular or peninsular microcontinental fragment collided with mainland southern California. -from Authors

Dillon, J. T.; Haxel, G. B.; Tosdal, R. M.

1990-01-01

449

Tme-300 Computer Evaluation of Telectro-Mek, Inc. Ram Drag and Thrust Computers.  

National Technical Information Service (NTIS)

The net thrust (TME-300), gross thrust (TME-300C1), ram drag (TME-300-C2) computers were evaluated on a J79-GE-8 engine at a simulated flight conditions ranging from static sea level to 50,000 ft, M = 1.4. The purpose of these tests was to determine the a...

J. E. Femia

1965-01-01

450

Thermal ground water flow systems in the thrust zone in southeastern Idaho  

SciTech Connect

The results of a regional study of thermal and non-thermal ground water flow systems in the thrust zone of southern Idaho and western Wyoming are presented. The study involved hydrogeologic and hydrochemical data collection and interpretation. Particular emphasis was placed on analyzing the role that thrust zones play in controlling the movement of thermal and non-thermal fluids.

Ralston, D.R.

1983-05-01

451

Effect of J-Groove on the Axial Thrust in Centrifugal Pump  

Microsoft Academic Search

In order to reduce the axial thrust of centrifugal pump, the J-Groove (shallow and wide groove along the pressure gradient) is put on the casing wall. With adequate shape of the grooves, the axial thrust can be reduced about 38% at the best efficiency point, and much more at the partial discharge area. Other performances such as head coefficient and

Jun Matsui; Takahiro Mugiyama

2010-01-01

452

Thrust belt geometry in the central Carolina slate belt North Carolina  

SciTech Connect

Newly recognized eastward-directed thrust faults and associated folds and cleavage constitute a major structural element in the central Carolina slate belt near Albemarle, North Carolina. At least two northwest-trending imbricate thrusts occur in a 10 km wide zone that trends 30 km along a northeast strike. Reconnaissance mapping suggests the presence of faults with similar style towards the west of this zone. Rocks directly involved in the thrust include the deep water rhythmites of the Tillery Formation that act as surface of detachment, and, also, a mafic rock that previously was mapped as a gabbro sill. Other field evidence documenting the thrusts includes: drag folds with a pronounced axial planar cleavage that parallels the faults; ramp areas with characteristic rootless folds; dragging of an earlier cleavage into fault surfaces; shear zones and kink bands with the same sense of movement as the thrusts. Axial planar cleavage results in part from pressure solution. The intensity of cleavage and the relative overall strain of the rocks increases from west to east across the thrust zone and suggests that thrusting progressed by successive propogation of footwall faults. Systematic and regular changes in the ratio of Bouma sequence intervals ((A+B+C+D)/E) show a marked discontinuity at the faults and suggest relative horizontal displacements of up to 14 km. Reconnaissance work suggests that the thrust may pre-date but are not younger than the regional low grade metamorphism.

Huntsman, J.R.; Dockal, J.A.

1985-01-01

453

Comparison of the dynamic response of radial and tangential magnetic flux thrust bearings  

Microsoft Academic Search

Theoretical predictions were made for the dynamic performance of a tangential flux magnetic thrust bearing. A prototype bearing was built with the stators and rotors made from tape wound strip. The performance of this bearing was measured and compared to the theoretical predictions and also to the performance of a radial flux thrust bearing. Tangential flux bearings are intrinsically amenable

Andrew Kenny; Alan B. Palazzolo

2002-01-01

454

Inelastic bowing of multispan fuel rods subjected to axial thrust and temperature gradients (LWBR Development Program)  

Microsoft Academic Search

Bowing of multispan rod-type fuel elements depends upon heat-generation gradients, variations in heat transfer processes, and axial thrust. The fundamental aspects of the analysis of axially compressed multispan inelastic beams are presented. Flexibility of supports in both axial and transverse directions is considered and the method is applicable to problems in which the thrust depends upon the transverse deflection as

1968-01-01

455

A thrust formula for an MPD thruster with applied-magnetic field  

NASA Astrophysics Data System (ADS)

In this paper a thrust formula for applied field MPD will be presented. The swirling velocity will be derived from the magnetic stress tensor and its conversion into axial energy into the magnetic nozzle will be analytically treated. The theoretical prediction of both swirling velocity and thrust will be compared to the measurements showing a reasonable agreement.

Coletti, M.

2012-12-01

456

Influence of axial thrust bearing defects on the dynamic behavior of an elastic shaft  

Microsoft Academic Search

In this work, the non-linear dynamic behavior of a flexible shaft is presented. The shaft is mounted in two journal bearings and axial load is supported by a hydrodynamic thrust bearing, at one end. The coupling between the axial thrust bearing behavior and the bending vibrations of the shaft is especially studied. The shaft is modeled by a typical beam

Sébastien Berger; Olivier Bonneau; Jean Frêne

2000-01-01

457

Non-contact thrust stand calibration method for repetitively pulsed electric thrusters.  

PubMed

A thrust stand calibration technique for use in testing repetitively pulsed electric thrusters for in-space propulsion has been developed and tested using a modified hanging pendulum thrust stand. In the implementation of this technique, current pulses are applied to a solenoid to produce a pulsed magnetic field that acts against a permanent magnet mounted to the thrust stand pendulum arm. The force on the magnet is applied in this non-contact manner, with the entire pulsed force transferred to the pendulum arm through a piezoelectric force transducer to provide a time-accurate force measurement. Modeling of the pendulum arm dynamics reveals that after an initial transient in thrust stand motion the quasi-steady average deflection of the thrust stand arm away from the unforced or "zero" position can be related to the average applied force through a simple linear Hooke's law relationship. Modeling demonstrates that this technique is universally applicable except when the pulsing period is increased to the point where it approaches the period of natural thrust stand motion. Calibration data were obtained using a modified hanging pendulum thrust stand previously used for steady-state thrust measurements. Data were obtained for varying impulse bit at constant pulse frequency and for varying pulse frequency. The two data sets exhibit excellent quantitative agreement with each other. The overall error on the linear regression fit used to determine the calibration coefficient was roughly 1%. PMID:22380121

Wong, Andrea R; Toftul, Alexandra; Polzin, Kurt A; Pearson, J Boise

2012-02-01

458

Thermal evolution of the Redbank thrust system, central Australia: Geochronological and phase-equilibrium constraints  

NASA Astrophysics Data System (ADS)

We constrain the thermal history of the Redbank thrust in central Australia by reviewing and substantially expanding on a small set of thermobarometric and field data, 40Ar/39Ar hornblende and biotite ages as well as chemical Th-U-Pb monazite and xenotime ages. Metamorphic PT data indicate peak conditions between 620°C and 800°C and between ˜6 and 8 kbar within the thrust system. For at least 50 km north of the thrust system (hanging wall) peak metamorphic conditions are fairly uniformly around ˜850°C and 10 kbar. The geochronological data are interpreted to indicate that these PT conditions were reached around 1780 Ma (Strangways Orogeny) north of the Redbank thrust zone and between around 1680 and ˜1600 (Argilke and Chewings tectonic events). Major cooling below or reheating up to 500°C of the entire region occurred around 1140 Ma (Teapot event). However, initial 40Ar/39Ar ages of biotites within and north of the thrust zone define the initiation of (re)activation along the Redbank thrust around 420 Ma. In combination we interpret the data to indicate exhumation of the thrust system from near 20 km to the surface between 420 Ma and 320 Ma. Recent authors have shown that exhumation processes like that described for the Redbank thrust here may have a substantial influence on the occurrence of intraplate orogeny by truncating a highly radioactive upper crust. Thus, our data may help to constrain the nature of intraplate orogeny in central Australia.

Biermeier, C.; Stüwe, K.; Foster, D. A.; Finger, F.

2003-02-01

459

Three-dimensional vortex analysis and aeroacoustic source characterization of jet core breakdown  

NASA Astrophysics Data System (ADS)

The three-dimensional behavior of jet core breakdown is investigated with experiments conducted on a free water jet at Re = 5000 by time-resolved tomographic particle image velocimetry (TR-TOMO PIV). The investigated domain encompasses the range between 0 and 10 jet diameters. The characteristic pulsatile motion of vortex ring shedding and pairing culminates with the growth of four primary in-plane and out-of-plane azimuthal waves and leads to the formation of streamwise vortices. Vortex ring humps are tilted and ejected along the axial direction as they are subjected to higher axial velocities. By the end of the potential core, this process causes the breakdown of the vortex ring regime and the onset of streamwise filaments oriented at 30°-45° to the jet axis and ``C'' shaped peripheral structures. The latter re-organize further downstream in filaments oriented along the azimuthal direction at the jet periphery. Instead, in the vicinity of the jet axis the filaments do not exhibit any preferential direction resembling the isotropic turbulent regime. Following Powell's aeroacoustic analogy, the instantaneous spatial distribution of the acoustic source term is mapped by the second time derivative of the Lamb vector, revealing the highest activity during vortex ring breakdown. A three-dimensional modal analysis of velocity, vorticity, Lamb vector, and Lamb vector second time derivative fields is conducted by proper orthogonal decomposition (POD) within the first 10 modes. The decomposed velocity fluctuations describe a helical organization in the region of the jet core-breakdown and, further downstream, jet axis flapping and precession motions. By the end of the potential core, vorticity modes show that vortex rings are dominated by travelling waves of radial and axial vorticity with a characteristic 40°-45° inclination to the jet axis. The Lamb vector and the Lamb vector second time derivative modes exhibit similar patterns for the azimuthal component, whereas the vortex ring coherence is described by the radial and the axial components. While velocity, vorticity, and Lamb vector modes are typically associated with Strouhal numbers (St) smaller than 0.9, the modes of the Lamb vector second time derivative are also related to higher frequencies (1.05 <= St <= 1.9) ascribed to the three-dimensional travelling waves. Far-field acoustic predictions are obtained on the basis of direct evaluation of Powell's analogy with TR-TOMO PIV data. The spectral analysis returns peaks at pairing (St = 0.36) and shedding (St = 0.72) frequency. A broader distribution with a hump between St = 1 and 2.25 is observed, which corresponds to the breakdown of ring vortices.

Violato, Daniele; Scarano, Fulvio

2013-01-01

460

Macro motion vector quantization  

NASA Astrophysics Data System (ADS)

A new algorithm is developed for reducing the bit rate required for motion vectors. This algorithm is a generalization of block matching motion estimation in which the search region is represented as a codebook of motion vectors. The new algorithm, called macro motion vector quantization (MMVQ), generalized our earlier MVQ by coding a group of motion vectors. The codebook is a set of macro motion vectors which represent the block locations of the small neighboring blocks in the previous frame. We develop an interative design algorithm for the codebook. Our experiments show that the variances of displaced frame differences (DFDs) are reduced significantly compared to block matching algorithm (BMA) with the macroblock size.

Lee, Yoon Y.; Woods, John W.

1995-04-01