A Performance and Plume Comparison of Xenon and Krypton Propellant on the SPT-100

DTIC Science & Technology

2012-07-02

HET (1.35 kW), performance measurements were made using an inverted pendulum thrust stand. The plume was also characterized by a Faraday probe and RPA...performance reduction for the case of the flight model SPT-100 HET (1.35 kW), per- formance measurements were made using an inverted pendulum thrust stand...where high thrust at reduced specific impulse is advantageous, such as orbit raising missions. Bismuth’s main drawback is that the metal must be

Structural analysis using thrust-fault hanging-wall sequence diagrams: Ogden duplex, Wasatch Range, Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schirmer, T.W.

1988-05-01

Detailed mapping and cross-section traverses provide the control for structural analysis and geometric modeling of the Ogden duplex, a complex thrust system exposed in the Wasatch Mountains, east of Ogden, Utah. The structures consist of east-dipping folded thrust faults, basement-cored horses, lateral ramps and folds, and tear faults. The sequence of thrusting determined by means of lateral overlap of horses, thrust-splay relationships, and a top-to-bottom piggyback development is Willard thrust, Ogden thrust, Weber thrust, and Taylor thrust. Major decollement zones occur in the Cambrian shales and limestones. The Tintic Quartzite is the marker for determining gross geometries of horses. Thismore » exposed duplex serves as a good model to illustrate the method of constructing a hanging-wall sequence diagram - a series of longitudinal cross sections that move forward in time and space, and show how a thrust system formed as it moved updip over various footwall ramps. A hanging wall sequence diagram also shows the complex lateral variations in a thrust system and helps to locate lateral ramps, lateral folds, tear faults, and other features not shown on dip-oriented cross sections. 8 figures.« less

Tiltmeter studies in earthquake prediction

USGS Publications Warehouse

Johnston, M.

1978-01-01

tilt measurements give us a means of monitoring vertical displacements or local uplift of the crust. The simplest type of tiltmeter is a stationary pendulum (fig. 1). As the Earth's surface distorts locally, the pendulum housing is tilted while, of course, the pendulum continues to hang vertically (that is, in the direction of the gravity vector). The tilt angle is the angle through which the pendulum housing is tilted. The pendulum is the inertial reference (the force of gravity remains unchanged at the site), and tilting of the instrument housing represents the moving reference frame. We note in passing that the tiltmeter could also be used to measure the force of gravity by using the pendulum in the same way as Henry Kater did in his celebrated measurement of g in 1817. 

Analogue modelling of thrust systems: Passive vs. active hanging wall strain accommodation and sharp vs. smooth fault-ramp geometries

NASA Astrophysics Data System (ADS)

Rosas, F. M.; Duarte, J. C.; Almeida, P.; Schellart, W. P.; Riel, N.; Terrinha, P.

2017-06-01

We present new analogue modelling results of crustal thrust-systems in which a deformable (brittle) hanging wall is assumed to endure passive internal deformation during thrusting, i.e. exclusively as a consequence of having to adapt its shape to the variable geometry of a rigid footwall. Building on previous experimental contributions, we specifically investigate the role of two so far overlooked critical variables: a) concave-convex (CC) vs. flat-ramp-flat (FRF) thrust ramp geometry; and b) presence vs. absence of a basal velocity discontinuity (VD). Regarding the first variable, we compare new results for considered (CC) smoother ramp types against classical experiments in which (FRF) sharp ramp geometries are always prescribed. Our results show that the considered sharp vs. smooth variation in the thrust-ramp geometry produces important differences in the distribution of the local stress field in the deformable hanging wall above both (lower and upper) fault bends, with corresponding styles of strain accommodation being expressed by marked differences in measured morpho-structural parameters. Regarding the second variable, we for the first time report analogue modelling results of this type of experiments in which basal VDs are experimentally prescribed to be absent. Our results critically show that true passive hanging wall deformation is only possible to simulate in the absence of any basal VD, since active shortening accommodation always necessarily occurs in the hanging wall above such a discontinuity (i.e. above the lower fault bend). In addition, we show that the morpho-structural configuration of model thrust-wedges formed for prescribed VD absence conditions complies well with natural examples of major overthrusts, wherein conditions must occur that approximate a frictionless state along the main basal thrust-plane.

Electronic system for the complex measurement of a Wilberforce pendulum

NASA Astrophysics Data System (ADS)

Kos, B.; Grodzicki, M.; Wasielewski, R.

2018-05-01

The authors present a novel application of a micro-electro-mechanical measurement system to the description of basic physical phenomena in a model Wilberforce pendulum. The composition of the kit includes a tripod with a mounted spring with freely hanging bob, a module GY-521 on the MPU 6050 coupled with an Arduino Uno, which in conjunction with a PC acts as measuring set. The system allows one to observe the swing of the pendulum in real time. Obtained data stays in good agreement with both theoretical predictions and previous works. The aim of this article is to introduce the study of a Wilberforce pendulum to the canon of physical laboratory exercises due to its interesting properties and multifaceted method of measurement.

Limited fluid in carbonate-shale hosted thrust faults of the Rocky Mountain Fold-and-Thrust Belt (Sun River Canyon, Montana)

NASA Astrophysics Data System (ADS)

OBrien, V. J.; Kirschner, D. L.

2001-12-01

It is widely accepted that fluids play a fundamental role in the movement of thrust faults in foreland fold-and-thrust belts. We have begun a combined structure-geochemistry study of faults in the Rocky Mountain fold-and-thrust belt in order to provide more insight into the occurrence and role(s) of fluid in the deformation of thrust faults. We focus on faults exposed in the Sun River Canyon of Montana, an area that contains some of the best exposures of the Rocky Mountain fold-and-thrust belt in the U.S. Samples were collected from two well exposed thrusts in the Canyon -- the Diversion and French thrusts. Both faults have thrust Mississippian dolostones over Cretaceous shales. Displacement exceeds several kilometers. Numerous small-displacement, subsidiary faults characterize the deformation in the hanging wall carbonates. The footwall shales accommodated more penetrative deformation, resulting in well developed foliation and small-scale folds. Stable isotope data have been obtained from host rock samples and veins from these faults. The data delimit an arcuate trend in oxygen-carbon isotope space. Approximately 50 host rock carbonate samples from the hanging walls have carbon and oxygen isotope values ranging from +3 to 0 and 28 to 19 per mil, respectively. There is no apparent correlation between isotopic values and distance from thrust fault at either locality. Fifteen samples of fibrous slickensides on small-displacement faults in the hanging walls have similar carbon and lower oxygen isotope values (down to 16 per mil). And 15 veins that either post-date thrusting or are of indeterminate origin have carbon and oxygen isotope values down to -3 and12 per mil, respectively. The isotopic data collected during the initial stages of this project are similar to some results obtained several hundred kilometers north in the Front Ranges of the Canadian Rockies (Kirschner and Kennedy, JGR 2000) and in carbonate fold-thrust belts of the Swiss Helvetic Alps and Italian Apennines. These data are consistent with limited infiltration of fluid through fractures and minor faults into hanging walls of large-displacement thrust faults.

String & Sticky Tape Experiments: Two-Dimensional Collisions Using Pendulums.

ERIC Educational Resources Information Center

Edge, R. D.

1989-01-01

Introduces a method for two-dimensional kinematics measurements by hanging marbles with long strings. Describes experimental procedures for conservation of momentum and obtaining the coefficient of restitution. Provides diagrams and mathematical expressions for the activities. (YP)

Precarious rock and overturned transformer evidence for ground shaking in the Ms 7.7 Kern County earthquake: An analog for disastrous shaking from a major thrust fault in the Los Angeles basin

USGS Publications Warehouse

Brune, J.N.; Anooshehpoor, A.; Shi, B.; Zheng, Yen

2004-01-01

Precariously balanced rocks and overturned transformers in the vicinity of the White Wolf fault provide constraints on ground motion during the 1952 Ms 7.7 Kern County earthquake, a possible analog for an anticipated large earthquake in the Los Angeles basin (Shaw et al., 2002; Dolan et al., 2003). On the northeast part of the fault preliminary estimates of ground motion on the footwall give peak accelerations considerably lower than predicted by standard regression curves. On the other hand, on the hanging-wall, there is evidence of intense ground shattering and lack of precarious rocks, consistent with the intense hanging-wall accelerations suggested by foam-rubber modeling, numerical modeling, and observations from previous thrust fault earthquakes. There is clear evidence of the effects of rupture directivity in ground motions on the hanging-wall side of the fault (from both precarious rocks and numerical simulations). On the southwest part of the fault, which is covered by sediments, the thrust fault did not reach the surface ("blind" thrust). Overturned and damaged transformers indicate significant transfer of energy from the hanging wall to the footwall, an effect that may not be as effective when the rupture reaches the surface (is not "blind"). Transformers near the up-dip projection of the fault tip have been damaged or overturned on both the hanging-wall and footwall sides of the fault. The transfer of energy is confirmed in a numerical lattice model and could play an important role in a similar situation in Los Angeles. We suggest that the results of this study can provide important information for estimating the effects of a large thrust fault rupture in the Los Angeles basin, specially given the fact that there is so little instrumental data from large thrust fault earthquakes.

Test stand for precise measurement of impulse and thrust vector of small attitude control jets

NASA Technical Reports Server (NTRS)

Woodruff, J. R.; Chisel, D. M.

1973-01-01

A test stand which accurately measures the impulse bit and thrust vector of reaction jet thrusters used in the attitude control system of space vehicles has been developed. It can be used to measure, in a vacuum or ambient environment, both impulse and thrust vector of reaction jet thrusters using hydrazine or inert gas propellants. The ballistic pendulum configuration was selected because of its accuracy, simplicity, and versatility. The pendulum is mounted on flexure pivots rotating about a vertical axis at the center of its mass. The test stand has the following measurement capabilities: impulse of 0.00004 to 4.4 N-sec (0.00001 to 1.0 lb-sec) with a pulse duration of 0.5 msec to 1 sec; static thrust of 0.22 to 22 N (0.05 to 5 lb) with a 5 percent resolution; and thrust angle alinement of 0.22 to 22 N (0.05 to 5 lb) thrusters with 0.01 deg accuracy.

25. LOBBY FIREPLACE. NOTE THE GEYSER DECORATING THE FIREPLACE SCREEN ...

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

25. LOBBY FIREPLACE. NOTE THE GEYSER DECORATING THE FIREPLACE SCREEN AND THE WEIGHTS AND PENDULUM HANGING FROM THE CLOCK DESIGNED BY ARCHITECT ROBERT C. REAMER. - Old Faithful Inn, 900' northeast of Snowlodge & 1050' west of Old Faithful Lodge, Lake, Teton County, WY

PPT Thrust Stand

NASA Technical Reports Server (NTRS)

Haag, Thomas W.

1995-01-01

A torsional-type thrust stand has been designed and built to test Pulsed Plasma Thrusters (PPT's) in both single shot and repetitive operating modes. Using this stand, momentum per pulse was determined strictly as a function of thrust stand deflection, spring constant, and natural frequency. No empirical corrections were required. The accuracy of the method was verified using a swinging impact pendulum. Momentum transfer data between the thrust stand and the pendulum were consistent to within 1%. Following initial calibrations, the stand was used to test a Lincoln Experimental Satellite (LES-8/9) thruster. The LES-8/9 system had a mass of approximately 7.5 kg, with a nominal thrust to weight ratio of 1.3 x 10(exp -5). A total of 34 single shot thruster pulses were individually measured. The average impulse bit per pulse was 266 microN-s, which was slightly less than the value of 300 microN-s published in previous reports on this device. Repetitive pulse measurements were performed similar to ordinary steady-state thrust measurements. The thruster was operated for 30 minutes at a repetition rate of 132 pulses per minute and yielded an average thrust of 573 microN. Using average thrust, the average impulse bit per pulse was estimated to be 260 microN-s, which was in agreement with the single shot data. Zero drift during the repetitive pulse test was found to be approximately 1% of the measured thrust.

Direct thrust measurement of a permanent magnet helicon double layer thruster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, K.; Lafleur, T.; Charles, C.

2011-04-04

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.

Emplacement history of a thrust sheet based on analysis of pressure solution cleavage and deformed fossils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Protzman, G.M.; Mitra, G.

The emplacement history of a thrust sheet is recorded by the strain accumulated in its hanging wall and footwall. Detailed studies of second order structures and analysis of strain due to pressure solution and plastic deformation allow the authors to determine the deformation history of the Meade thrust in the Idaho - Wyoming thrust belt. Emplacement of the Meade thrust was accompanied by the formation of a series of second order in echelon folds in the footwall. Temporal relations based on detailed structural studies show that these folds, which are confined to the Jurassic Twin Creek Formation, formed progressively inmore » front of the advancing Meade thrust and were successively truncated and overridden by footwall imbricates of the Meade thrust. The Twin Creek Formation in both the hanging wall and footwall of the Meade thrust is penetratively deformed, with a well developed pressure solution cleavage. In addition, plastic strain is recorded by deformed Pentacrinus within fossil hash layers in the Twin Creek. Much of this penetrative deformation took place early in the history of the thrust sheet as layer parallel shortening, and the cleavage and deformed fossils behaved passively during subsequent folding and faulting. The later stages of deformation may be sequentially removed through balancing techniques to track successive steps in the deformation. This strain history, which is typical of an internal thrust sheet, is partly controlled by the lithologies involved, timing between successive thrusts, and the amount of interaction between major faults.« less

Structural analysis of hanging wall and footwall blocks within the Río Guanajibo fold-and-thrust belt in Southwest Puerto Rico

NASA Astrophysics Data System (ADS)

Laó-Dávila, Daniel A.; Llerandi-Román, Pablo A.

2017-01-01

The Río Guanajibo fold-and-thrust belt (RGFT), composed of Cretaceous serpentinite and volcano-sedimentary rocks, represents the deformation front of a contractional event in SW Puerto Rico during the Paleogene. Previous studies inferred structural and stratigraphic relationships from poorly exposed outcrops. New road cuts exposed the Yauco (YF) and El Rayo Formations (ERF) providing insights on the deformation of the hanging wall and footwall. We described the nature and orientation of faults and folds and analyzed the kinematic indicators to characterize the deformation. The YF occurs in the hanging wall and shows a sequence of folded, medium-bedded mudstone and thinly bedded shale and sandstone. Major folds strike NW-SE and are gentle with steeply inclined axial planes and sub-horizontal fold axes. Minor folds are open with moderately inclined axial planes and gently to moderately inclined SE-plunging fold axes. NW-SE striking reverse and thrust faults cut layers and show movement to the SW. Steep left-lateral faults strike NW-SE and NE-SW, and smaller right-lateral strike-slip faults strike NNE-SSW. At the footwall, the ERF consists of bioclastic limestone and polymictic orthoconglomerates and paraconglomerates. Reverse and strike-slip faults cut along lithological contacts. Results suggest that the hanging wall and footwall accommodated strain along preexisting weaknesses, which are dependent on lithology and sedimentary structures. The kinematic analysis suggests that shortening in the NE-SW direction was partitioned between folding and interlayer shortening, accommodated by flexural slip, and reverse and left-lateral faults that resulted from contraction. The RGFT represents the Paleogene back arc deformation of a bivergent thrust system.

Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum

NASA Technical Reports Server (NTRS)

Brady, David A.; White, Harold G.; March, Paul; Lawrence, James T.; Davies, Frank J.

2014-01-01

This paper describes the test campaigns designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma. This paper will not address the physics of the quantum vacuum plasma thruster (QVPT), but instead will describe the recent test campaign. In addition, it contains a brief description of the supporting radio frequency (RF) field analysis, lessons learned, and potential applications of the technology to space exploration missions. During the first (Cannae) portion of the campaign, approximately 40 micronewtons of thrust were observed in an RF resonant cavity test article excited at approximately 935 megahertz and 28 watts. During the subsequent (tapered cavity) portion of the campaign, approximately 91 micronewtons of thrust were observed in an RF resonant cavity test article excited at approximately 1933 megahertz and 17 watts. Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level. Test campaign results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma.

Thrust Slip Rates as a Control on the Presence and Spatial Distribution of High Metamorphic Heating Rates in Collisional Systems: The "Hot Iron" Model Revisited

NASA Astrophysics Data System (ADS)

Thigpen, R.; Ashley, K. T.; Law, R. D.; Mako, C. A.

2017-12-01

In natural systems, two key observations indicate that major strain discontinuities such as faults and shear zones should play a fundamental role in orogenic thermal evolution: (1) Large faults and shear zones often separate components of the composite orogen that have experienced broadly different thermal and deformational histories, and (2) quantitative metamorphic and diffusional studies indicate that heating rates are much faster and the duration of peak conditions much shorter in natural collisional systems than those predicted by numerical continuum deformation models. Because heat transfer processes such as conduction usually operate at much slower time scales than rates of other tectonic processes, thermal evolution is often transient and thus can be strongly influenced by tectonic disturbances that occur at rates much faster than thermal relaxation. Here, we use coupled thermal-mechanical finite element models of thrust faults to explore how fault slip rate may fundamentally influence the thermal evolution of individual footwall and hanging wall thrust slices. The model geometry involves a single crustal-scale thrust with a dip of 25° that is translated up the ramp at average velocities of 20, 35, and 50 km Myr-1, interpreted to represent average to relatively high slip rates observed in many collisional systems. Boundary conditions include crustal radioactive heat production, basal mantle heat flow, and surface erosion rates that are a function of thrust rate and subsequent topography generation. In the models, translation of the hanging wall along the crustal-scale detachment results in erosion, exhumation, and retrograde metamorphism of the emerging hanging wall topography and coeval burial, `hot iron' heating, and prograde metamorphism of the thrust footwall. Thrust slip rates of 20, 35, and 50 km Myr-1 yield maximum footwall heating rates ranging from 55-90° C Myr-1 and maximum hanging wall cooling rates of 138-303° C Myr-1. These relatively rapid heating rates explain, in part, the presence of chemical diffusion profiles in metamorphic minerals that are indicative of high heating rates. Additionally, the relatively high cooling rates explain preservation of chemical zoning, as rapid cooling prevents diffusive profiles from being substantially modified during exhumation.

Testing and evaluation of the LES-6 pulsed plasma thruster by means of a torsion pendulum system

NASA Technical Reports Server (NTRS)

Hamidian, J. P.; Dahlgren, J. B.

1973-01-01

Performance characteristics of the LES-6 pulsed plasma thruster over a range of input conditions were investigated by means of a torsion pendulum system. Parameters of particular interest included the impulse bit and time average thrust (and their repeatability), specific impulse, mass ablated per discharge, specific thrust, energy per unit area, efficiency, and variation of performance with ignition command rate. Intermittency of the thruster as affected by input energy and igniter resistance were also investigated. Comparative experimental data correlation with the data presented. The results of these tests indicate that the LES-6 thruster, with some identifiable design improvements, represents an attractive reaction control thruster for attitude contol applications on long-life spacecraft requiring small metered impulse bits for precise pointing control of science instruments.

Performance of a 100 kW class applied field MPD thruster

NASA Technical Reports Server (NTRS)

Mantenieks, Maris A.; Sovey, James S.; Myers, Roger M.; Haag, Thomas W.; Raitano, Paul; Parkes, James E.

1989-01-01

Performance of a 100 kW, applied field magnetoplasmadynamic (MPD) thruster was evaluated and sensitivities of discharge characteristics to arc current, mass flow rate, and applied magnetic field were investigated. Thermal efficiencies as high as 60 percent, thrust efficiencies up to 21 percent, and specific impulses of up to 1150 s were attained with argon propellant. Thrust levels up to 2.5 N were directly measured with an inverted pendulum thrust stand at discharge input powers up to 57 kW. It was observed that thrust increased monotonically with the product of arc current and magnet current.

Summary of the 2012 Inductive Pulsed Plasma Thruster Development and Testing Program

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Martin, A. K.; Eskridge, R. H.; Kimberlin, A. C.; Addona, B. M.; Devineni, A. P.; Dugal-Whitehead, N. R.; Hallock, A. K.

2013-01-01

Inductive pulsed plasma thrusters are spacecraft propulsion devices in which energy is capacitively stored and then discharged through an inductive coil. While these devices have shown promise for operation at high efficiency on a range of propellants, many technical issues remain before they can be used in flight applications. A conical theta-pinch thruster geometry was fabricated and tested to investigate potential improvements in propellant utilization relative to more common, flat-plate planar coil designs. A capacitor charging system is used to permit repetitive discharging of thrusters at multiple cycles per second, with successful testing accomplished at a repetition-rate of 5 Hz at power levels of 0.9, 1.6, and 2.5 kW. The conical theta-pinch thruster geometry was tested at cone angles of 20deg, 38deg, and 60deg, with single-pulse operation at 500 J/pulse and repetitionrate operation with the 38deg model quantified through direct thrust measurement using a hanging pendulum thrust stand. A long-lifetime valve was designed and fabricated, and initial testing was performed to measure the valve response and quantify the leak rate at beginning-of-life. Subscale design and testing of a capacitor charging system required for operation on a spacecraft is reported, providing insights into the types of components needed in the circuit topology employed. On a spacecraft, this system would accept as input a lower voltage from the spacecraft DC bus and boost the output to the high voltage required to charge the capacitors of the thruster.

Determination of tectonic shortening rates from progressively deformed flights of terraces above the Chelungpu and Changhua thrust ramps, Taiwan

NASA Astrophysics Data System (ADS)

Yue, L.; Suppe, J.

2007-12-01

The Chelungpu and Changhua thrust ramps in central Taiwan show contrasting hanging-wall structural geometries that suggest different kinematics, even though they involve the same stratigraphic section and basal detachment. The Chelungpu thrust shows a classic fault-bend folding geometry, which predicts folding solely by kink-band migration, whereas the hanging wall of the Changhua thrust demonstrates the characteristic geometry of a shear fault-bend folding, which predicts a progressive limb rotation with minor kink-band migration. We test the kinematic predictions of classic and shear fault-bend folding theories by analyzing deformed flights of terraces and coseismic displacements in the Mw=7.6 Chi-Chi earthquake. The Chelungpu terraces shows differences in uplift magnitudes across active axial surfaces that closely approximate the assumptions of classical fault-bend folding, including constant fault-parallel displacement, implying conservation of bed length, and hanging-wall uplift rates that are proportional to the sine of the fault dip. This provides a basis for precise determination of total fault slip since the formation of each terrace and combined with terrace dating gives long- term fault-slip rates for the Chelungpu thrust system. An estimation of the long term fault-slip rate of the Chelungpu thrust in the north Hsinshe terrace yields 15 mm/yr over the last 55 ka, which is similar to the combined shortening rate of 16 mm/y on the Chelungpu and Chushiang thrusts in the south estimated by Simoes et al. in 2006. Evan the coseismic displacements of 3 to 9m in the Chi-Chi earthquake are approximately fault-parallel but have additional transient components that are averaged out over the timescale of terrace deformation, which represents 10-100 large earthquakes. In contrast, terrace deformation in the hanging wall of the Changhua thrust ramp shows progressive limb rotation, as predicted from its shear fault-bend folding geometry, which combined with terrace dating allows an estimation of the long term fault-slip rate of 21 mm/yr over the last 31 ka. A combined shortening rate of 37 mm/yr is obtained for this part of the western Taiwan thrust belt, which is about 45 percent of the total plate-tectonic shortening rate across Taiwan. The Changhua shear fault-bend fold ramp is in the early stages of its development with only 1.7km total displacement whereas the Chelungpu classical fault-bend folding ramp in the same stratigraphy has nearly an order of magnitude more displacement (~14 km). We suggest that shear fault-bend folding may be favored mechanically at low displacement, whereas classical fault-bend folding would be favored at large displacement.

Determination of tectonic shortening rates from progressively deformed flights of terraces above the Chelungpu and Changhua thrust ramps, Taiwan

NASA Astrophysics Data System (ADS)

Yue, L.; Suppe, J.

2004-12-01

The Chelungpu and Changhua thrust ramps in central Taiwan show contrasting hanging-wall structural geometries that suggest different kinematics, even though they involve the same stratigraphic section and basal detachment. The Chelungpu thrust shows a classic fault-bend folding geometry, which predicts folding solely by kink-band migration, whereas the hanging wall of the Changhua thrust demonstrates the characteristic geometry of a shear fault-bend folding, which predicts a progressive limb rotation with minor kink-band migration. We test the kinematic predictions of classic and shear fault-bend folding theories by analyzing deformed flights of terraces and coseismic displacements in the Mw=7.6 Chi-Chi earthquake. The Chelungpu terraces shows differences in uplift magnitudes across active axial surfaces that closely approximate the assumptions of classical fault-bend folding, including constant fault-parallel displacement, implying conservation of bed length, and hanging-wall uplift rates that are proportional to the sine of the fault dip. This provides a basis for precise determination of total fault slip since the formation of each terrace and combined with terrace dating gives long- term fault-slip rates for the Chelungpu thrust system. An estimation of the long term fault-slip rate of the Chelungpu thrust in the north Hsinshe terrace yields 15 mm/yr over the last 55 ka, which is similar to the combined shortening rate of 16 mm/y on the Chelungpu and Chushiang thrusts in the south estimated by Simoes et al. in 2006. Evan the coseismic displacements of 3 to 9m in the Chi-Chi earthquake are approximately fault-parallel but have additional transient components that are averaged out over the timescale of terrace deformation, which represents 10-100 large earthquakes. In contrast, terrace deformation in the hanging wall of the Changhua thrust ramp shows progressive limb rotation, as predicted from its shear fault-bend folding geometry, which combined with terrace dating allows an estimation of the long term fault-slip rate of 21 mm/yr over the last 31 ka. A combined shortening rate of 37 mm/yr is obtained for this part of the western Taiwan thrust belt, which is about 45 percent of the total plate-tectonic shortening rate across Taiwan. The Changhua shear fault-bend fold ramp is in the early stages of its development with only 1.7km total displacement whereas the Chelungpu classical fault-bend folding ramp in the same stratigraphy has nearly an order of magnitude more displacement (~14 km). We suggest that shear fault-bend folding may be favored mechanically at low displacement, whereas classical fault-bend folding would be favored at large displacement.

Timing and conditions of peak metamorphism and cooling across the Zimithang Thrust, Arunachal Pradesh, India

NASA Astrophysics Data System (ADS)

Warren, Clare J.; Singh, Athokpam K.; Roberts, Nick M. W.; Regis, Daniele; Halton, Alison M.; Singh, Rajkumar B.

2014-07-01

The Zimithang Thrust juxtaposes two lithotectonic units of the Greater Himalayan Sequence in Arunachal Pradesh, NE India. Monazite U-Pb, muscovite 40Ar/39Ar and thermobarometric data from rocks in the hanging and footwall constrain the timing and conditions of their juxtaposition across the structure, and their subsequent cooling. Monazite grains in biotite-sillimanite gneiss in the hanging wall yield LA-ICP-MS U-Pb ages of 16 ± 0.2 to 12.7 ± 0.4 Ma. A schistose gneiss within the high strain zone yields overlapping-to-younger monazite ages of 14.9 ± 0.3 to 11.5 ± 0.3 Ma. Garnet-staurolite-mica schists in the immediate footwall yield older monazite ages of 27.3 ± 0.6 to 17.1 ± 0.2 Ma. Temperature estimates from Ti-in-biotite and garnet-biotite thermometry suggest similar peak temperatures were achieved in the hanging and footwalls (~ 525-650 °C). Elevated temperatures of ~ 700 °C appear to have been reached in the high strain zone itself and in the footwall further from the thrust. Single grain fusion 40Ar/39Ar muscovite data from samples either side of the thrust yield ages of ~ 7 Ma, suggesting that movement along the thrust juxtaposed the two units by the time the closure temperature of Ar diffusion in muscovite had been reached. These data confirm previous suggestions that major orogen-parallel out-of-sequence structures disrupt the Greater Himalayan Sequence at different times during Himalayan evolution, and highlight an eastwards-younging trend in 40Ar/39Ar muscovite cooling ages at equivalent structural levels along Himalayan strike.

Developing an inverted Barrovian sequence; insights from monazite petrochronology

NASA Astrophysics Data System (ADS)

Mottram, Catherine M.; Warren, Clare J.; Regis, Daniele; Roberts, Nick M. W.; Harris, Nigel B. W.; Argles, Tom W.; Parrish, Randall R.

2014-10-01

In the Himalayan region of Sikkim, the well-developed inverted metamorphic sequence of the Main Central Thrust (MCT) zone is folded, thus exposing several transects through the structure that reached similar metamorphic grades at different times. In-situ LA-ICP-MS U-Th-Pb monazite ages, linked to pressure-temperature conditions via trace-element reaction fingerprints, allow key aspects of the evolution of the thrust zone to be understood for the first time. The ages show that peak metamorphic conditions were reached earliest in the structurally highest part of the inverted metamorphic sequence, in the Greater Himalayan Sequence (GHS) in the hanging wall of the MCT. Monazite in this unit grew over a prolonged period between ∼37 and 16 Ma in the southerly leading-edge of the thrust zone and between ∼37 and 14.5 Ma in the northern rear-edge of the thrust zone, at peak metamorphic conditions of ∼790 °C and 10 kbar. Monazite ages in Lesser Himalayan Sequence (LHS) footwall rocks show that identical metamorphic conditions were reached ∼4-6 Ma apart along the ∼60 km separating samples along the MCT transport direction. Upper LHS footwall rocks reached peak metamorphic conditions of ∼655 °C and 9 kbar between ∼21 and 16 Ma in the more southerly-exposed transect and ∼14.5-12 Ma in the northern transect. Similarly, lower LHS footwall rocks reached peak metamorphic conditions of ∼580 °C and 8.5 kbar at ∼16 Ma in the south, and 9-10 Ma in the north. In the southern transect, the timing of partial melting in the GHS hanging wall (∼23-19.5 Ma) overlaps with the timing of prograde metamorphism (∼21 Ma) in the LHS footwall, confirming that the hanging wall may have provided the heat necessary for the metamorphism of the footwall. Overall, the data provide robust evidence for progressively downwards-penetrating deformation and accretion of original LHS footwall material to the GHS hanging wall over a period of ∼5 Ma. These processes appear to have occurred several times during the prolonged ductile evolution of the thrust. The preserved inverted metamorphic sequence therefore documents the formation of sequential 'paleo-thrusts' through time, cutting down from the original locus of MCT movement at the LHS-GHS protolith boundary and forming at successively lower pressure and temperature conditions. The petrochronologic methods applied here constrain a complex temporal and thermal deformation history, and demonstrate that inverted metamorphic sequences can preserve a rich record of the duration of progressive ductile thrusting.

Hall Effect Thruster Ground Testing Challenges

DTIC Science & Technology

2009-08-18

the specic impulse, g is Earth’s gravitational constant, η is the thrust efficiency, ṁ is the propellant...lines form a composite spring with an effective spring constant of K . The thruster displaces the inverted pendulum a distance x, and the thrust stand...destabilizing force as shown in Eqn. 5. x = T K − Mgh (5) The effective spring constant is adjusted such that the unstable condition of K = Mg/h is avoided,

Prograde evolution of the Scottish Caledonides and tectonic implications

NASA Astrophysics Data System (ADS)

Ashley, Kyle T.; Thigpen, J. Ryan; Law, Richard D.

2015-05-01

Recent thermometric analyses of samples collected in thrust-parallel structural transects across the Scandian (435-415 Ma) orogenic wedge in northwest Scotland provide a comprehensive characterization of the synorogenic retro-wedge thermal architecture. However, the paucity of petrologically-important metamorphic mineral phases (e.g., staurolite, Al-silicates) has limited investigation of pressure-temperature (P-T) histories, which hinders our ability to examine the nature of orogen-scale kinematic and thermal coupling. New data collected along a foreland-to-hinterland transect from the Moine to the Naver thrust sheets provides additional constraints for characterizing the prograde metamorphic evolution. In addition, we characterized Ti diffusion profiles in quartz inclusions in garnet to constrain duration of metamorphic heating. These results are used to develop coupled kinematic-thermal models of Scandian orogenic evolution. Early garnet core growth conditions are constrained by isopleth intersections, with peak P-T estimates determined by conventional exchange and net transfer thermobarometry and thermodynamic calculations. Most samples follow normal prograde heating and burial profiles, with peak conditions of 450 °C and 5.0 kbar in the immediate hanging wall to the Moine thrust, increasing in temperature and pressure to 733 °C and 9.5 kbar in the immediate hanging wall to the Naver thrust. These normal prograde pressure trajectories are interpreted to reflect burial of incipient thrust sheets beneath the overriding wedge at the leading edge of the orogen. Prograde heating coeval with burial is interpreted to result from surface-directed isotherm perturbation due to thrust-related advection in the overriding wedge. One exception to this is a sample from the top of the Moine thrust sheet, where prograde heating occurs during decompression (540 °C and 8.1 kbar to 590 °C and 7.0 kbar). In this case, the short lag times between motion on the Moine and Ben Hope thrusts may have limited advectionary heating until after exhumation associated with motion on the underlying Moine thrust was underway. Ti diffusion profiles in quartz inclusions in garnet suggest the near-peak thermal evolution of these rocks occurred over very short time scales (< 200,000 years). While most of the garnets are inferred to be Scandian in age, we document evidence for pre-Scandian garnet cores in structurally higher (more hinterland positioned) samples that must have grown under higher temperatures. In the hanging wall of the Moine thrust, high grossular garnets with estimated formation conditions > 9 kbar are probably of detrital origin.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2011-08-15

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{sup -1}, while a larger thrust of 4 mN is obtained at a similar power for a length of 9.5 cm andmore » a flow rate of 1.65 mg s{sup -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.« less

Morphological evolution of spiders predicted by pendulum mechanics.

PubMed

Moya-Laraño, Jordi; Vinković, Dejan; De Mas, Eva; Corcobado, Guadalupe; Moreno, Eulalia

2008-03-26

Animals have been hypothesized to benefit from pendulum mechanics during suspensory locomotion, in which the potential energy of gravity is converted into kinetic energy according to the energy-conservation principle. However, no convincing evidence has been found so far. Demonstrating that morphological evolution follows pendulum mechanics is important from a biomechanical point of view because during suspensory locomotion some morphological traits could be decoupled from gravity, thus allowing independent adaptive morphological evolution of these two traits when compared to animals that move standing on their legs; i.e., as inverted pendulums. If the evolution of body shape matches simple pendulum mechanics, animals that move suspending their bodies should evolve relatively longer legs which must confer high moving capabilities. We tested this hypothesis in spiders, a group of diverse terrestrial generalist predators in which suspensory locomotion has been lost and gained a few times independently during their evolutionary history. In spiders that hang upside-down from their webs, their legs have evolved disproportionately longer relative to their body sizes when compared to spiders that move standing on their legs. In addition, we show how disproportionately longer legs allow spiders to run faster during suspensory locomotion and how these same spiders run at a slower speed on the ground (i.e., as inverted pendulums). Finally, when suspensory spiders are induced to run on the ground, there is a clear trend in which larger suspensory spiders tend to run much more slowly than similar-size spiders that normally move as inverted pendulums (i.e., wandering spiders). Several lines of evidence support the hypothesis that spiders have evolved according to the predictions of pendulum mechanics. These findings have potentially important ecological and evolutionary implications since they could partially explain the occurrence of foraging plasticity and dispersal constraints as well as the evolution of sexual size dimorphism and sociality.

Timing, quantification and tectonic modelling of Pliocene-Quaternary movements in the NW Himalaya: evidence from fission track dating

NASA Astrophysics Data System (ADS)

Jain, A. K.; Kumar, Devender; Singh, Sandeep; Kumar, Ashok; Lal, Nand

2000-07-01

Variable exhumation rates, deduced from the Pliocene-Quaternary FT zircon-apatite ages from the Himalayan Metamorphic Belt (HMB) of the NW Himalaya along the Sutlej Valley in Himachal Pradesh, have been modelled in the tectonic framework of fast exhumed Lesser Himalayan windows, which caused lateral extensional sliding of the metamorphic nappe cover along the well-known Main Central Thrust (MCT) and differential movements along thrust zones as well. In the northern belt of the Higher Himalayan Crystallines (HHC), two distinct clusters of the FT apatite ages have been deciphered: apatite ages having a weighted mean of 4.9±0.2 Ma (1 σ) in basal parts on the hanging wall of the MCT, and 1.49±0.07 Ma (1 σ) in the hanging wall of a newly, recognized NE, dipping Chaura thrust further north. Fast exhumation of the Chaura thrust hanging wall has been inferred at a rate of 4.82±0.55 mm/yr from the zircon-apatite cogenetic pairs during 1.54 Ma and 0.97 Ma, and 2.01±0.35 mm/yr since 1.49 Ma. In comparison, its foot wall has been exhumed at a much slower rate of 0.61±0.10 mm/yr since 4.9 Ma. The overlying Vaikrita Thrust zone rocks reveal an exhumation rate of 1.98±0.34 mm/yr from 2.70±0.40 Ma to 1.31±0.22 Ma and 2.29±0.66 mm/yr since 1.31±0.22 Ma. Using these data, a vertical displacement of ca. 2.08±0.68 km has been calculated along the Chaura thrust between 4.9 and 1.50 Ma on an average rate of 0.6 mm/yr. It is of the order of 1.18 km from 2.70 Ma to 1.54 Ma along the Vaikrita Thrust, and 0.78 mm/yr from 1.31 Ma to 0.97 Ma, and has behaved as an extensional normal fault during these periods. Tectonic modelling of the exhumation rates in the NW Himalaya reveals fastest uplifting Himalayan domes and windows like the Nanga Parbat in Pakistan, Suru and Chisoti domes in Zanskar and Kishwar-Kulu-Rampur Window axis in SE Kashmir and Himachal Pradesh during Pliocene-Quaternary. These windows appear to have caused lateral extensional sliding of the Himalayan metamorphic nappes in the lower parts. The middle parts of the HHC belt have witnessed both overthrusting and extensional faulting due to complex and variable exhumation patterns within the hanging and foot walls of the MCT and Vaikrita Thrust along the Sutlej Valley, thus causing movement of upthrust crustal wedge between the extensional ones. Thus, FT zircon-apatite ages provide evidence for the presence of a number of crustal wedges having distinct tectonothermal history within the HHC.

A Hydrous Seismogenic Fault Rock Indicating A Coupled Lubrication Mechanism

NASA Astrophysics Data System (ADS)

Okamoto, S.; Kimura, G.; Takizawa, S.; Yamaguchi, H.

2005-12-01

In the seismogenic subduction zone, the predominant mechanisms have been considered to be fluid induced weakening mechanisms without frictional melting because the subduction zone is fundamentally quite hydrous under low temperature conditions. However, recently geological evidence of frictional melting has been increasingly reported from several ancient accretionary prisms uplifted from seismogenic depths of subduction zones (Ikesawa et al., 2003; Austrheim and Andersen, 2004; Rowe et al., 2004; Kitamura et al., 2005) but relationship between conflicting mechanisms; e.g. thermal pressurization of fluid and frictional melting is still unclear. We found a new exposure of pseudotachylyte from a fossilized out-of-sequence thrust (OOST) , Nobeoka thrust in the accretionary complex, Kyushu, southwest Japan. Hanging-wall and foot-wall are experienced heating up to maximum temperature of about 320/deg and about 250/deg, respectively. Hanging-wall rocks of the thrust are composed of shales and sandstones deformed plastically. Foot-wall rocks are composed of shale matrix melange with sandstone and basaltic blocks deformed in a brittle fashion (Kondo et al, 2005). The psudotachylyte was found from one of the subsidiary faults in the hanging wall at about 10 m above the fault core of the Nobeoka thrust. The fault is about 1mm in width, and planer rupture surface. The fault maintains only one-time slip event because several slip surfaces and overlapped slip textures are not identified. The fault shows three deformation stages: The first is plastic deformation of phyllitic host rocks; the second is asymmetric cracking formed especially in the foot-wall of the fault. The cracks are filled by implosion breccia hosted by fine carbonate minerals; the third is frictional melting producing pseudotachylyte. Implosion breccia with cracking suggests that thermal pressurization of fluid and hydro-fracturing proceeded frictional melting.

Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum

NASA Technical Reports Server (NTRS)

Brady, David; White, Harold G.; March, Paul; Lawrence, James T.; Davies, Frank J.

2014-01-01

This paper describes the eight-day August 2013 test campaign designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma. This paper will not address the physics of the quantum vacuum plasma thruster, but instead will describe the test integration, test operations, and the results obtained from the test campaign. Approximately 30-50 micro-Newtons of thrust were recorded from an electric propulsion test article consisting primarily of a radio frequency (RF) resonant cavity excited at approximately 935 megahertz. Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level, within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure. Several different test configurations were used, including two different test articles as well as a reversal of the test article orientation. In addition, the test article was replaced by an RF load to verify that the force was not being generated by effects not associated with the test article. The two test articles were designed by Cannae LLC of Doylestown, Pennsylvania. The torsion pendulum was designed, built, and operated by Eagleworks Laboratories at the NASA Johnson Space Center of Houston, Texas. Approximately six days of test integration were required, followed by two days of test operations, during which, technical issues were discovered and resolved. Integration of the two test articles and their supporting equipment was performed in an iterative fashion between the test bench and the vacuum chamber. In other words, the test article was tested on the bench, then moved to the chamber, then moved back as needed to resolve issues. Manual frequency control was required throughout the test. Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article). Test data gathered includes torsion pendulum displacement measurements which are used to calculate generated force, still imagery in the visible spectrum to document the physical configuration, still imagery in the infrared spectrum to characterize the thermal environment, and video imagery. Post-test data includes static and animated graphics produced during RF resonant cavity characterization using the COMSOL Multiphysics® software application. Excerpts from all of the above are included and discussed in this paper. Lessons learned from test integration and operations include identification of the need to replace manual control of the resonant cavity target frequency with an automated frequency control capability. Future test plans include the development of an automatic frequency control circuit. Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma. Future test plans include independent verification and validation at other test facilities.

Pseudotachylyte formation vs. mylonitization - repeated cycles of seismic fracture and aseismic creep in the middle crust (Woodroffe Thrust, Central Australia)

NASA Astrophysics Data System (ADS)

Wex, Sebastian; Mancktelow, Neil; Hawemann, Friedrich; Camacho, Alfredo; Pennacchioni, Giorgio

2014-05-01

The Musgrave Ranges in Central Australia provide excellent exposure of the shallowly south-dipping Woodroffe Thrust, which placed ~1200 Ma granulites onto amphibolite facies gneisses. This ~400 km long E-W structure developed under mid-crustal conditions during the intracratonic Petermann Orogeny around 550 Ma. From field observations and measurements, the shortening direction is constrained to be N-S and the movement sense top-to-north. Ductile deformation during this process almost entirely localized in the footwall rocks, developing a zone of mylonites, ultramylonites and sheared pseudotachylytes, several hundred metres wide, with pseudotachylyte abundance rapidly decreasing further into the footwall. In contrast, the hanging wall behaved in a predominantly brittle manner, producing significant volumes of pseudotachylyte breccia and isolated veins, but was otherwise mostly unaffected and only weakly foliated. The difference in rheological behaviour is reflected in the pseudotachylyte fabric, which is dominantly sheared in the footwall and largely unsheared in the hanging wall. Low-strain domains in the footwall show that localized shearing initiated along pseudotachylyte veins and that shear zones and mylonitic foliations were in turn exploited by subsequent pseudotachylyte veins. Neither phyllonitization nor synkinematic growth of new muscovite is observed. In contrast to models with a simple brittle-to-viscous transition, these observations show that a continuous cycle of brittle fracturing and shearing is active in dry mid-crustal environments. The products of multiple earthquakes and ductile overprint, repeatedly exploiting the same structural discontinuity, are composite layers of sheared pseudotachylyte. In the Woodroffe Thrust, these layers are numerous and frequently observed parallel to the foliation in the footwall mylonites. The thickest of these sheared pseudotachylyte horizons (~15 m thick) mark the immediate contact to the hanging wall and almost entirely consist of pseudotachylyte matrix. Particularly in the footwall, but locally also in the hanging wall, shear strain can additionally be concentrated along the margins of dolerite dykes, whose mineral assemblages will be studied to determine the metamorphic conditions that were active during development of the Woodroffe Thrust.

Spatial heterogeneity of stress and driving fluid pressure ratio inferred from mineral vein orientation along seismogenic megasplay fault (Nobeoka Thrust, Japan)

NASA Astrophysics Data System (ADS)

Otsubo, M.; Miyakawa, A.; Kawasaki, R.; Sato, K.; Yamaguchi, A.; Kimura, G.

2015-12-01

Fault zones including the damage zone and the fault core have a controlling influence on the crust's mechanical and fluid flow properties (e.g., Faulkner et al., 2010). In the Nankai subduction zone, southwest Japan, the velocity structures indicate the contrast of the pore fluid pressure between hanging wall and footwall of the megasplay fault (Tsuji et al., 2014). Nobeoka Thrust, which is an on-land example of an ancient megasplay fault, provides an excellent record of deformation and fluid flow at seismogenic depths (Kondo et al., 2005; Yamaguchi et al., 2011). Yamaguchi et al. (2011) showed that the microchemical features of syn-tectonic mineral veins along fault zones of the Nobeoka Thrust. The inversion approaches by using the mineral vein orientations can provide stress regimes and fluid driving pressure ratio (Jolly and Sanderson, 1997) at the time of fracture opening (e.g., Yamaji et al., 2010). In this study, we show (1) stress regimes in co- and post seismic period of the Nobeoka Thrust and (2) spatial heterogeneity of the fluid driving pressure ratio by using the mineral veins (extension veins) around the fault zone in the Nobeoka Thrust. We applied the inversion approach proposed by Sato et al. (2013) to estimate stress regimes by using the mineral vein orientations. The estimated stresses are the normal faulting stress regimes of which sigma 3 axes are almost horizontal and trend NNW-SSE in both the hanging wall and the footwall. The stress regimes are the negative stress for the reverse faulting stress regime that Kawasaki et al. (2014) estimated from the minor faults in the core samples of the Nobeoka Thrust Drilling Project (Hamahashi et al., 2013). And, the orientation of the sigma 3 axes of the estimated stress regime is parallel to the slip direction of the Nobeoka Thrust (Top to SSE; Kondo et al., 2005). These facts indicate the normal faulting stress regime at the time of fracture opening is the secondary stress generated by the slip of the Nobeoka Thrust. We estimated the fluid driving pressure ratio P* at the time of fracture opening by using the Mohr circle analysis that has been carried out using the vein orientation data. The estimated P* are 0.05 and 0.15-0.40 in the hanging wall and footwall, respectively. These results indicate that there are spatial differences of pore fluid pressure in the interseismic period.

Experimental Results of Schlicher's Thrusting Antenna

NASA Technical Reports Server (NTRS)

Fralick, Gustave C.; Niedra, Janis M.

2001-01-01

Experiments were conducted to test the claims by Rex L. Schlicher, et al., (Patent 5,142,86 1) that a certain antenna geometry produces thrust greatly exceeding radiation reaction, when driven by repetitive, fast rise, and relatively slower decay current pulses. In order to test this hypothesis, the antenna was suspended by strings as a 3 in pendulum. Current pulses were fed to the antenna along the suspension path by a very flexible coaxial line constructed from loudspeaker cable and copper braid sheath. When driving the antenna via this cabling, our pulser was capable of sustaining 1200 A pulses at a rate of 30 per second up to a minute. In this way, bursts of pulses could be delivered in synch with the pendulum period in order to build up any motion. However, when using a laser beam passing through a lens attached to the antenna to amplify linear displacement by a factor of at least 25, no correlated motion of the beam spot could be detected on a distant wall. We conclude, in agreement with the momentum theorem of classical electromagnetic theory, that any thrust produced is far below practically useful levels. Hence, within classical electrodynamics, there is little hope of detecting any low level motion that cannot be explained by interactions with surrounding structural steel and the Earth's magnetic field.

Fault Structural Control on Earthquake Strong Ground Motions: The 2008 Wenchuan Earthquake as an Example

NASA Astrophysics Data System (ADS)

Zhang, Yan; Zhang, Dongli; Li, Xiaojun; Huang, Bei; Zheng, Wenjun; Wang, Yuejun

2018-02-01

Continental thrust faulting earthquakes pose severe threats to megacities across the world. Recent events show the possible control of fault structures on strong ground motions. The seismogenic structure of the 2008 Wenchuan earthquake is associated with high-angle listric reverse fault zones. Its peak ground accelerations (PGAs) show a prominent feature of fault zone amplification: the values within the 30- to 40-km-wide fault zone block are significantly larger than those on both the hanging wall and the footwall. The PGA values attenuate asymmetrically: they decay much more rapidly in the footwall than in the hanging wall. The hanging wall effects can be seen on both the vertical and horizontal components of the PGAs, with the former significantly more prominent than the latter. All these characteristics can be adequately interpreted by upward extrusion of the high-angle listric reverse fault zone block. Through comparison with a low-angle planar thrust fault associated with the 1999 Chi-Chi earthquake, we conclude that different fault structures might have controlled different patterns of strong ground motion, which should be taken into account in seismic design and construction.

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

USGS Publications Warehouse

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

1989-01-01

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

Direct measurement of the impulse in a magnetic thrust chamber system for laser fusion rocket

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maeno, Akihiro; Yamamoto, Naoji; Nakashima, Hideki

2011-08-15

An experiment is conducted to measure an impulse for demonstrating a magnetic thrust chamber system for laser fusion rocket. The impulse is produced by the interaction between plasma and magnetic field. In the experiment, the system consists of plasma and neodymium permanent magnets. The plasma is created by a single-beam laser aiming at a polystyrene spherical target. The impulse is 1.5 to 2.2 {mu}Ns by means of a pendulum thrust stand, when the laser energy is 0.7 J. Without magnetic field, the measured impulse is found to be zero. These results indicate that the system for generating impulse is working.

Thrust Stand Characterization of the NASA Evolutionary Xenon Thruster (NEXT)

NASA Technical Reports Server (NTRS)

Diamant, Kevin D.; Pollard, James E.; Crofton, Mark W.; Patterson, Michael J.; Soulas, George C.

2010-01-01

Direct thrust measurements have been made on the NASA Evolutionary Xenon Thruster (NEXT) ion engine using a standard pendulum style thrust stand constructed specifically for this application. Values have been obtained for the full 40-level throttle table, as well as for a few off-nominal operating conditions. Measurements differ from the nominal NASA throttle table 10 (TT10) values by 3.1 percent at most, while at 30 throttle levels (TLs) the difference is less than 2.0 percent. When measurements are compared to TT10 values that have been corrected using ion beam current density and charge state data obtained at The Aerospace Corporation, they differ by 1.2 percent at most, and by 1.0 percent or less at 37 TLs. Thrust correction factors calculated from direct thrust measurements and from The Aerospace Corporation s plume data agree to within measurement error for all but one TL. Thrust due to cold flow and "discharge only" operation has been measured, and analytical expressions are presented which accurately predict thrust based on thermal thrust generation mechanisms.

Simple Pendulum Determination of the Gravitational Constant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parks, Harold V.; Sandia National Laboratories, Albuquerque, New Mexico 87185; Faller, James E.

We determined the Newtonian constant of gravitation G by interferometrically measuring the change in spacing between two free-hanging pendulum masses caused by the gravitational field from large tungsten source masses. We find a value for G of (6.672 34{+-}0.000 14)x10{sup -11} m{sup 3} kg{sup -1} s{sup -2}. This value is in good agreement with the 1986 Committee on Data for Science and Technology (CODATA) value of (6.672 59{+-}0.000 85)x10{sup -11} m{sup 3} kg{sup -1} s{sup -2}[Rev. Mod. Phys. 59, 1121 (1987)] but differs from some more recent determinations as well as the latest CODATA recommendation of (6.674 28{+-}0.000 67)x10{sup -11}more » m{sup 3} kg{sup -1} s{sup -2}[Rev. Mod. Phys. 80, 633 (2008)].« less

Landforms along transverse faults parallel to axial zone of folded mountain front, north-eastern Kumaun Sub-Himalaya, India

NASA Astrophysics Data System (ADS)

Luirei, Khayingshing; Bhakuni, S. S.; Negi, Sanjay S.

2017-02-01

The shape of the frontal part of the Himalaya around the north-eastern corner of the Kumaun Sub-Himalaya, along the Kali River valley, is defined by folded hanging wall rocks of the Himalayan Frontal Thrust (HFT). Two parallel faults (Kalaunia and Tanakpur faults) trace along the axial zone of the folded HFT. Between these faults, the hinge zone of this transverse fold is relatively straight and along these faults, the beds abruptly change their attitudes and their widths are tectonically attenuated across two hinge lines of fold. The area is constituted of various surfaces of coalescing fans and terraces. Fans comprise predominantly of sandstone clasts laid down by the steep-gradient streams originating from the Siwalik range. The alluvial fans are characterised by compound and superimposed fans with high relief, which are generated by the tectonic activities associated with the thrusting along the HFT. The truncated fan along the HFT has formed a 100 m high-escarpment running E-W for ˜5 km. Quaternary terrace deposits suggest two phases of tectonic uplift in the basal part of the hanging wall block of the HFT dipping towards the north. The first phase is represented by tilting of the terrace sediments by ˜30 ∘ towards the NW; while the second phase is evident from deformed structures in the terrace deposit comprising mainly of reverse faults, fault propagation folds, convolute laminations, flower structures and back thrust faults. The second phase produced ˜1.0 m offset of stratification of the terrace along a thrust fault. Tectonic escarpments are recognised across the splay thrust near south of the HFT trace. The south facing hill slopes exhibit numerous landslides along active channels incising the hanging wall rocks of the HFT. The study area shows weak seismicity. The major Moradabad Fault crosses near the study area. This transverse fault may have suppressed the seismicity in the Tanakpur area, and the movement along the Moradabad and Kasganj-Tanakpur faults cause the neotectonic activities as observed. The role of transverse fault tectonics in the formation of the curvature cannot be ruled out.

Structural styles of the Guess Creek fault block beneath the Great Smoky thrust sheet, Blount County, Tennessee

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, M.W.; Davidson, G.L.; Heller, J.A.

1993-03-01

A road cut along US 321 N, approximately 1 km NW of Walland, TN, exposes a previously unexposed complexly deformed section of Middle Ordovician clastic wedge [Chickamauga Group, Sevier Shale] sedimentary rocks. It provides an excellent opportunity to analyze both the lithologic assemblages and complex folding and faulting beneath the Great Smoky thrust sheet. Arkosic quartzite of the Lower Cambrian Cochran Conglomerate [Chilhowee Group], has been thrust over weaker Sevier Shale in the hanging wall of the Guess Creek fault. Regionally, the Great Smoky fault separates metamorphosed Precambrian to Lower Cambrian clastic shelf, slope, and rift facies rocks of themore » western Blue Ridge from Cambro-Ordovician carbonate shelf and orogenic wedge deposits of the foreland fold and thrust belt. West of the Great Smoky fault, the Guess Creek fault has been interpreted to floor duplexed Cambro-Ordovician rocks exposed in windows beneath the Great Smoky thrust sheet in the vicinity of the Great Smoky Mountains National Park. The Sevier Shale here consists of variably cleaved shale, siltstone, sandstone, and conglomerate. It exhibits a variety of fold styles throughout the exposure, ranging from predominantly noncylindrical tight folds to broad, open structures. A weak axial-planar pencil cleavage is developed in the Middle Ordovician shale and siltstone, along with a secondary cleavage that transects the axial surfaces of the folds. Minor thrust faults within the Sevier Shale appear to have formed by propagation through tightened fold hinges or bedding-parallel slip. The fold pattern observed in the roadcut appears to be partly the result of movement along a tear fault that broke both the hanging wall and footwall of the Great Smoky thrust sheet after emplacement. Slickenline orientations along minor thrust surfaces in the Cochran Conglomerate indicate eastward-directed, oblique-slip movement of the tear fault.« less

Low-temperature thermochronology of the Laramide Ranges and eastward translation of shortening in the Sevier Belt, Wyoming, Utah and Montana

NASA Astrophysics Data System (ADS)

Peyton, Sara Lynn

This dissertation contains two studies that use very different techniques to investigate the Mesozoic and Cenozoic tectonics of the western USA. The first study investigates shortening in the Sevier thrust belt of northeast Utah and southwest Wyoming using cross sections and seismic reflection data. The second study investigates the low-temperature thermochronology of the Laramide Ranges using apatite (U-Th)/He dating. We used cross sections and seismic reflection data to investigate bed length discrepancies within the hanging wall of the Absaroka thrust in the Sevier thrust belt of northeast Utah and southwest Wyoming. Restoration of cross sections suggests that there was ˜8-14 km of pre-Absaroka-thrust shortening above the Jurassic Preuss salt detachment, but not below it, in the hanging wall of the Absaroka thrust. Reflection seismic data over the hanging wall of the Crawford thrust show that the Crawford thrust is not offset along the Preuss salt detachment, indicating that the additional shortening on the Absaroka plate was transferred east before main movement on the Crawford thrust. Although early displacement on the Crawford thrust cannot be ruled out as the cause of the extra shortening, surface and subsurface geology suggests slip from the western thrust system (Willard and Lost Creek thrusts) was transferred several tens of kilometers east along the Jurassic Preuss salt detachment between ˜102-90 Ma, to the future location of the Absaroka thrust hanging wall. The lack of deformation of the Crawford thrust on the seismic data, along with shortening and extension estimates from cross sections, also indicate that the magnitude of Paleocene and post-early Eocene shortening on the Medicine Butte thrust was essentially offset by subsequent extension on the middle Eocene to late Oligocene Almy-Acocks normal-fault system. For the second study in this dissertation, we dated 91 borehole and surface samples from Laramide-age, basement-cored uplifts of the Rocky Mountain foreland (Wind River, Beartooth, Bighorn and Laramie Ranges) and the Uncompahgre Uplift using the apatite (U-Th)/He system. Apatite (U-Th)/He ages generally decrease with increasing subsurface depth (decreasing elevation) and most samples show age dispersion ranging from tens to hundreds of Myr. Additionally, several samples show correlations between apatite (U-Th)/He age and effective U concentration (eU = [U] + 0.235[Th]) of the crystal, indicating that radiation damage has affected He diffusivity, and hence (U-Th)/ He age. Many surface and near-surface samples have apatite (U-Th)/He ages that are older than corresponding apatite fission-track ages. Forward modeling of Laramide-type thermal histories using a radiation damage diffusion model showed that (U-Th)/He ages may be widely dispersed, and may be older than corresponding apatite fission-track ages within a fossil He partial retention zone. Most of our samples, however, do not show the correlation between (U-Th)/He age and eU predicted by radiation damage diffusion models. We investigated the influence of both grain size and eU content and show that the effects of grain size can obscure (U-Th)/ He age-eU correlations and, similarly, the effect of eU variation can obscure (U-Th)/ He age-grain size correlations. (U-Th)/He ages that are older than fission-track ages from high peaks in the Wind River Range, and from some samples from the Beartooth Range, are most likely the result of He implantation from high eU phases. Best-fit thermal histories from the inversion of age-eU pairs were extrapolated to other elevations to create model age-elevation profiles for a range of eU concentrations. These model profiles approximate our real data. Inverse modeling of (U-Th)/He age data suggests that rapid exhumation within the Laramide province likely began earlier in the Bighorn Mountains (before ˜71 Ma) than the Beartooth Range (before ˜58 Ma), and that the borehole at the northern end of the Laramie Range penetrated a fault sliver at depth.

Laser Plasma Microthruster Performance Evaluation

NASA Astrophysics Data System (ADS)

Luke, James R.; Phipps, Claude R.

2003-05-01

The micro laser plasma thruster (μLPT) is a sub-kilogram thruster that is capable of meeting the Air Force requirements for the Attitude Control System on a 100-kg class small satellite. The μLPT uses one or more 4W diode lasers to ablate a solid fuel, producing a jet of hot gas or plasma which creates thrust with a high thrust/power ratio. A pre-prototype continuous thrust experiment has been constructed and tested. The continuous thrust experiment uses a 505 mm long continuous loop fuel tape, which consists of a black laser-absorbing fuel material on a transparent plastic substrate. When the laser is operated continuously, the exhaust plume and thrust vector are steered in the direction of the tape motion. Thrust steering can be avoided by pulsing the laser. A torsion pendulum thrust stand has been constructed and calibrated. Many fuel materials and substrates have been tested. Best performance from a non-energetic fuel material was obtained with black polyvinyl chloride (PVC), which produced an average of 70 μN thrust and coupling coefficient (Cm) of 190 μN/W. A proprietary energetic material was also tested, in which the laser initiates a non-propagating detonation. This material produced 500 μN of thrust.

Effect of applied magnetic nozzle on an MPD Thruster

NASA Astrophysics Data System (ADS)

Ando, Akira; Izawa, Yuki; Okawa, Kohei; Hashima, Yoko; Watanabe, Hiroshi; Tanaka, Nozomi

2012-10-01

Electric propulsion systems are suitable for long-term mission in space due to its higher specific impulse. An Magneto-Plasma-Dynamic Thruster (MPDT) is one of the promising thrusters of high power electric propulsion systems. It has been reported that the thrust performance of an MPDT can be improved by applying an axial magnetic field on it. In order to investigate the effect of applied field on an MPDT, we have investigated plume plasma parameters and thrust performance in an applied field MPDT. Different types of divergent magnetic nozzle were applied to an MPDT, and thrust was measured using a pendulum type thrust target. Experiments were performed with hydrogen, helium, and argon as propellant gas. Thrust increased with a discharge current up to 6kA and applied magnetic field up to 0.4T. Maximum thrust of 7N was obtained when the peak position of the applied magnetic field was set upstream of the muzzle of the MPDT. The highest thrust performance was obtained with hydrogen gas with divergent magnetic nozzle applied to the MPDT.

Low grade metamorphism fluid circulation in a sedimentary environment thrust fault zone: properties and modeling

NASA Astrophysics Data System (ADS)

Trincal, Vincent; Lacroix, Brice; Buatier, Martine D.; Charpentier, Delphine; Labaume, Pierre; Lahfid, Abdeltif

2014-05-01

In fold-and-thrust belts, shortening is mainly accommodated by thrust faults that can constitute preferential pathways for fluid circulation. The present study focuses on the Pic de Port Vieux thrust, a second-order thrust related to major Gavarnie thrust in the Axial Zone of the Pyrenees. The fault juxtaposes lower Triassic red siltstones and sandstones in the hanging-wall and Upper Cretaceous limestone in the footwall. A dense network of synkinematic quartz-chlorite veins is present in outcrop and allows to unravel the nature of the fluid that circulated in the fault zone. The hanging wall part of fault zone comprises a core which consists of intensely foliated phyllonite; the green color of this shear zone is related to the presence of abundant newly-formed chlorite. Above, the damage zone consists of red pelites and sandstones. Both domains feature kinematic markers like S-C type shear structures associated with shear and extension quartz-chlorite veins and indicate a top to the south displacement. In the footwall, the limestone display increasing mylonitization and marmorization when getting close to the contact. In order to investigate the mineralogical and geochemical changes induced by deformation and subsequent fluid flow, sampling was conducted along a complete transect of the fault zone, from the footwall limestone to the red pelites of the hanging wall. In the footwall limestone, stable isotope and Raman spectroscopy analyzes were performed. The strain gradient is strongly correlated with a high decrease in δ18OV PDB values (from -5.5 to -14) when approaching the thrust (i.e. passing from limestone to marble) while the deformation temperatures estimated with Raman spectroscopy on carbon remain constant around 300° C. These results suggest that deformation is associated to a dynamic calcite recrystallization of carbonate in a fluid-open system. In the hanging wall, SEM observations, bulk chemical XRF analyses and mineral quantification from XRD analyses were conducted in order to compare the green phyllonites from the fault core zone with the red pelites from the damage zone. Quartz, muscovite 2M1, chlorite (clinochlore), calcite and rutile are present in all samples. Hematite occurs in the damage zone but is absent in the core zone. Synkinematic chlorites are abundant in the core and damage zones and are mainly located in veins, sometimes in association with quartz. The temperature of formation of these newly-formed chlorites is 300-350° C according to Inoue (2009) geothermometer. Mössbauer spectroscopic analyses were performed on bulk rock samples. In the damage zone, Fe3+/Fetotal vary between 0.7 and 0.8, whereas in the core zone Fe3+/Fetotal is about 0.35. This decrease in Fe3+ from the damage zone to the core zone can be related to the dissolution of hematite. In contrast, Fe3+/Fetotal in phyllosilicates is clearly related to the chlorite content relative to mica, as Fe2+ increases with chlorite content. All these data allow us to propose a model of fluid circulation in relation with the Pic de Port Vieux thrust activity. The origin of the fluid, its interactions with host-rock and the consequences on fault zone mineralizations will be discussed. Inoue, A., Meunier, A., Patrier-Mas, P., Rigault, C., Beaufort, D., Vieillard, P., 2009. Application of chemical geothermometry to low-temperature trioctahedral chlorites. Clay Clay Min. 57, 371-382.

Major Oil Plays In Utah And Vicinity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas Chidsey

2007-12-31

Utah oil fields have produced over 1.33 billion barrels (211 million m{sup 3}) of oil and hold 256 million barrels (40.7 million m{sup 3}) of proved reserves. The 13.7 million barrels (2.2 million m3) of production in 2002 was the lowest level in over 40 years and continued the steady decline that began in the mid-1980s. However, in late 2005 oil production increased, due, in part, to the discovery of Covenant field in the central Utah Navajo Sandstone thrust belt ('Hingeline') play, and to increased development drilling in the central Uinta Basin, reversing the decline that began in the mid-1980s.more » The Utah Geological Survey believes providing play portfolios for the major oil-producing provinces (Paradox Basin, Uinta Basin, and thrust belt) in Utah and adjacent areas in Colorado and Wyoming can continue this new upward production trend. Oil plays are geographic areas with petroleum potential caused by favorable combinations of source rock, migration paths, reservoir rock characteristics, and other factors. The play portfolios include descriptions and maps of the major oil plays by reservoir; production and reservoir data; case-study field evaluations; locations of major oil pipelines; identification and discussion of land-use constraints; descriptions of reservoir outcrop analogs; and summaries of the state-of-the-art drilling, completion, and secondary/tertiary recovery techniques for each play. The most prolific oil reservoir in the Utah/Wyoming thrust belt province is the eolian, Jurassic Nugget Sandstone, having produced over 288 million barrels (46 million m{sup 3}) of oil and 5.1 trillion cubic feet (145 billion m{sup 3}) of gas. Traps form on discrete subsidiary closures along major ramp anticlines where the depositionally heterogeneous Nugget is also extensively fractured. Hydrocarbons in Nugget reservoirs were generated from subthrust Cretaceous source rocks. The seals for the producing horizons are overlying argillaceous and gypsiferous beds in the Jurassic Twin Creek Limestone, or a low-permeability zone at the top of the Nugget. The Nugget Sandstone thrust belt play is divided into three subplays: (1) Absaroka thrust - Mesozoic-cored shallow structures, (2) Absaroka thrust - Mesozoic-cored deep structures, and (3) Absaroka thrust - Paleozoic-cored shallow structures. Both of the Mesozoic-cored structures subplays represent a linear, hanging wall, ramp anticline parallel to the leading edge of the Absaroka thrust. Fields in the shallow Mesozoic subplay produce crude oil and associated gas; fields in the deep subplay produce retrograde condensate. The Paleozoic-cored structures subplay is located immediately west of the Mesozoic-cored structures subplays. It represents a very continuous and linear, hanging wall, ramp anticline where the Nugget is truncated against a thrust splay. Fields in this subplay produce nonassociated gas and condensate. Traps in these subplays consist of long, narrow, doubly plunging anticlines. Prospective drilling targets are delineated using high-quality, two-dimensional and three-dimensional seismic data, forward modeling/visualization tools, and other state-of-the-art techniques. Future Nugget Sandstone exploration could focus on more structurally complex and subtle, thrust-related traps. Nugget structures may be present beneath the leading edge of the Hogsback thrust and North Flank fault of the Uinta uplift. The Jurassic Twin Creek Limestone play in the Utah/Wyoming thrust belt province has produced over 15 million barrels (2.4 million m{sup 3}) of oil and 93 billion cubic feet (2.6 billion m{sup 3}) of gas. Traps form on discrete subsidiary closures along major ramp anticlines where the low-porosity Twin Creek is extensively fractured. Hydrocarbons in Twin Creek reservoirs were generated from subthrust Cretaceous source rocks. The seals for the producing horizons are overlying argillaceous and clastic beds, and non-fractured units within the Twin Creek. The Twin Creek Limestone thrust belt play is divided into two subplays: (1) Absaroka thrust-Mesozoic-cored structures and (2) Absaroka thrust - Paleozoic-cored structures. The Mesozoic-cored structures subplay represents a linear, hanging wall, ramp anticline parallel to the leading edge of the Absaroka thrust. Fields in this subplay produce crude oil and associated gas. The Paleozoic-cored structures subplay is located immediately west of the Mesozoic-cored structures subplay. It represents a very continuous and linear, hanging wall, ramp anticline where the Twin Creek is truncated against a thrust splay. Fields in this subplay produce nonassociated gas and condensate. Traps in both subplays consist of long, narrow, doubly plunging anticlines.« less

Evidence for Crustal-Scale Imbrication and non-Equilibrium Topography in the Southern Central Range, Taiwan

NASA Astrophysics Data System (ADS)

Byrne, T. B.; Huang, C.; Ouimet, W. B.; Rau, R.; Hsieh, M.; Lee, Y.

2011-12-01

We integrate a suite of new and recently re-interpreted profiles of the 3-D crustal velocity structure from the southern Central Range of Taiwan with geomorphic data from the range and propose that the topography is supported by a crustal-scale, west-verging thrust. The extent and geometry of the thrust is indicated by contours of P-wave velocity that are progressively overturned from south to north, placing high Vp rocks above low Vp rocks. The interpreted thrust dips gently east (15-20 degrees) and carries pre-Tertiary metamorphic rocks and Eocene to Miocene rocks with a well-developed slaty cleavage in its hanging wall. The thrust is interpreted to cut up section to the west and link with the basal detachment of the fold-and-thrust belt. Leveling data1 along the South Cross-Island Highway also suggest that the thrust is active. Along-strike profiles suggest that the thrust is propagating southward, consistent with a progressive decrease in mean elevation and an increase in reset apatite fission track ages from north to south. The hanging wall of the propagating thrust also correlates with anomalous areas of low topographic relief that straddle the crest of the southern part of the range. The areas of low relief are fringed by stream channels with relatively high stream gradient indexes and do not appear related to weaker rock types, glacial erosion, or lower rock uplift rates along the range crest. We propose that the surfaces represent relict topography that formed prior to a recent acceleration in rock uplift rate, consistent with the presence of a propagating, crustal-scale thrust in the subsurface. Taken together, these results raise questions about the notion of steady state topography and critically tapered wedges in Taiwan. 1) Ching, Kuo-En, Hsieh, M.-L., Johnson, K. M., Chen, K-H., Rau, R.-J., Yang M., Modern vertical deformation rates and mountain building in Taiwan from precise leveling and continuous GPS observations, 2000-2008, in press, JGR.

A 205 Hour Krypton Propellant Life Test of the SPT-100 Operating at 3 kW

DTIC Science & Technology

2013-09-01

advantageous, such as orbit raising missions. Bismuth’s main drawback is that the metal must be vaporized to be ionized and accelerated within a Hall...the performance of the SPT-100 operating on krypton was characterized using an inverted pendulum thrust stand over a wide range of thruster operating

A miniature electrothermal thruster using microwave-excited microplasmas: Thrust measurement and its comparison with numerical analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takao, Yoshinori; Eriguchi, Koji; Ono, Kouichi

2007-06-15

A microplasma thruster has been developed, consisting of a cylindrical microplasma source 10 mm long and 1.5 mm in inner diameter and a conical micronozzle 1.0-1.4 mm long with a throat of 0.12-0.2 mm in diameter. The feed or propellant gas employed is Ar at pressures of 10-100 kPa, and the surface-wave-excited plasma is established by 4.0 GHz microwaves at powers of <10 W. The thrust has been measured by a combination of target and pendulum methods, exhibiting the performance improved by discharging the plasma. The thrust obtained is 1.4 mN at an Ar gas flow rate of 60 SCCMmore » (1.8 mg/s) and a microwave power of 6 W, giving a specific impulse of 79 s and a thrust efficiency of 8.7%. The thrust and specific impulse are 0.9 mN and 51 s, respectively, in cold-gas operation. A comparison with numerical analysis indicates that the pressure thrust contributes significantly to the total thrust at low gas flow rates, and that the micronozzle tends to have an isothermal wall rather than an adiabatic.« less

Initiation process of a thrust fault revealed by analog experiments

NASA Astrophysics Data System (ADS)

Yamada, Yasuhiro; Dotare, Tatsuya; Adam, Juergen; Hori, Takane; Sakaguchi, Hide

2016-04-01

We conducted 2D (cross-sectional) analog experiments with dry sand using a high resolution digital image correlation (DIC) technique to reveal initiation process of a thrust fault in detail, and identified a number of "weak shear bands" and minor uplift prior to the thrust initiation. The observations suggest that the process can be divided into three stages. Stage 1: characterized by a series of abrupt and short-lived weak shear bands at the location where the thrust will be generated later. Before initiation of the fault, the area to be the hanging wall starts to uplift. Stage 2: defined by the generation of the new thrust and its active displacement. The location of the new thrust seems to be constrained by its associated back-thrust, produced at the foot of the surface slope (by the previous thrust). The activity of the previous thrust turns to zero once the new thrust is generated, but the timing of these two events is not the same. Stage 3: characterized by a constant displacement along the (new) thrust. Similar minor shear bands can be seen in the toe area of the Nankai accretionary prism, SW Japan and we can correlate the along-strike variations in seismic profiles to the model results that show the characteristic features in each thrust development stage.

Structural geology of western part of Lemhi Range, east-central Idaho

USGS Publications Warehouse

Tysdal, Russell G.

2002-01-01

The Poison Creek Anticline is a major fold that occupies a large part of the western part of the Lemhi Range. The fold is now broken by normal faults, but removal of displacement on the normal faults permitted reconstruction of the anticline. The fold formed during late Mesozoic compressional deformation in the hinterland of the Cordilleran thrust belt. It is in the hanging wall of the Poison Creek thrust fault, a major fault in east-central Idaho, that displaced Proterozoic strata over lower Paleozoic rocks.

A model for the origin of Himalayan anatexis and inverted metamorphism

NASA Astrophysics Data System (ADS)

Harrison, T. Mark; Grove, Marty; Lovera, Oscar M.; Catlos, E. J.

1998-11-01

The origin of the paired granite belts and inverted metamorphic sequences of the Himalaya has generally been ascribed to development of the Main Central Thrust (MCT). Although a variety of models have been proposed that link early Miocene anatexis with inverted metamorphism, recent dating studies indicate that recrystallization of elements of the MCT footwall occurred in the central Himalaya as recently as ˜6 Ma. The recognition that hanging wall magmatism and footwall metamorphism are not spatially and temporally related renders unnecessary the need for exceptional physical conditions to explain generation of the High Himalayan leucogranites and North Himalayan granites, which differ in age, petrogenesis, and emplacement style. We suggest that their origin is linked to shear heating on a continuously active thrust that cuts through Indian supracrustal rocks that had previously experienced low degrees of partial melting. Numerical simulations assuming a shear stress of 30 MPa indicate that continuous slip on the Himalayan decollement beginning at 25 Ma could trigger partial melting reactions leading to formation of the High Himalayan granite chain between 25 and 20 Ma and the North Himalayan belt between 17 and 8 Ma. The ramp-flat geometry we apply to model the Himalayan thrust system requires that the presently exposed rocks of the hanging wall resided at middle crustal levels above the decollement throughout the early and middle Miocene. Late Miocene, out-of-sequence thrusting within the broad shear zone beneath the MCT provides a mechanism to bring these rocks to the surface in their present location (i.e., well to the north of the present tectonic front) and has the additional benefit of explaining how the inverted metamorphic sequences formed beneath the MCT. We envision that formation of the MCT Zone involved successive accretion of tectonic slivers of the Lesser Himalayan Formations to the hanging wall and incorporate these effects into the model. The model predicts continued anatexis up to 400 km north of the Himalayan range, consistent with the timing and geochemistry of leucogranites exhumed on the flank of a south Tibetan rift.

Comparison of fault-related folding algorithms to restore a fold-and-thrust-belt

NASA Astrophysics Data System (ADS)

Brandes, Christian; Tanner, David

2017-04-01

Fault-related folding means the contemporaneous evolution of folds as a consequence of fault movement. It is a common deformation process in the upper crust that occurs worldwide in accretionary wedges, fold-and-thrust belts, and intra-plate settings, in either strike-slip, compressional, or extensional regimes. Over the last 30 years different algorithms have been developed to simulate the kinematic evolution of fault-related folds. All these models of fault-related folding include similar simplifications and limitations and use the same kinematic behaviour throughout the model (Brandes & Tanner, 2014). We used a natural example of fault-related folding from the Limón fold-and-thrust belt in eastern Costa Rica to test two different algorithms and to compare the resulting geometries. A thrust fault and its hanging-wall anticline were restored using both the trishear method (Allmendinger, 1998; Zehnder & Allmendinger, 2000) and the fault-parallel flow approach (Ziesch et al. 2014); both methods are widely used in academia and industry. The resulting hanging-wall folds above the thrust fault are restored in substantially different fashions. This is largely a function of the propagation-to-slip ratio of the thrust, which controls the geometry of the related anticline. Understanding the controlling factors for anticline evolution is important for the evaluation of potential hydrocarbon reservoirs and the characterization of fault processes. References: Allmendinger, R.W., 1998. Inverse and forward numerical modeling of trishear fault propagation folds. Tectonics, 17, 640-656. Brandes, C., Tanner, D.C. 2014. Fault-related folding: a review of kinematic models and their application. Earth Science Reviews, 138, 352-370. Zehnder, A.T., Allmendinger, R.W., 2000. Velocity field for the trishear model. Journal of Structural Geology, 22, 1009-1014. Ziesch, J., Tanner, D.C., Krawczyk, C.M. 2014. Strain associated with the fault-parallel flow algorithm during kinematic fault displacement. Mathematical Geosciences, 46(1), 59-73.

Contrasting terrace systems of the lower Moulouya river as indicator of crustal deformation in NE Morocco

NASA Astrophysics Data System (ADS)

Rixhon, Gilles; Bartz, Melanie; El Ouahabi, Meriam; Szemkus, Nina; Brückner, Helmut

2017-02-01

The Moulouya river has the largest catchment in Morocco and drains an area characterized by active crustal deformation during the Late Cenozoic due to the N-S convergence between the African and Eurasian plates. As yet, its Pleistocene terrace sequence remains poorly documented. Our study focuses on the lowermost reach of the river in north-eastern Morocco, which drains the Zebra-Triffa sedimentary basin directly upstream of the estuary. New field observations, measurements and sedimentological data reveal contrasting fluvial environments on each side of a newly identified, W-E striking thrust zone disrupting the sedimentary basin. On the one hand, long-lasting fluvial aggradation, materialized by 37 m-thick stacked terraces, has occurred in the footwall of the thrust. On the other hand, the hanging wall is characterized by a well-preserved terrace staircase, with three Pleistocene terrace levels. Whilst the identification of this thrust zone question some previous interpretations about the local (hydro-)geology, it is consistent with the statement that most of the Plio-Quaternary deformation in the eastern Rif mountains has concentrated in this region of Morocco. Our new data and interpretations also agree with morphometric indicators showing that the whole Moulouya catchment is at desequilibrium state (i.e. several knickzones in its longitudinal profile), showing several knickzones in its longitudinal profile, is at disequilibrium state. We also suggest that the knickzone in the Beni Snassen gorge, located directly upstream of the Zebra-Triffa sedimentary basin, could (partly) result from a transient fluvial reaction to Late Cenozoic thrusting activity and correlated uplift in the hanging wall.

Was Himalayan normal faulting triggered by initiation of the Ramgarh-Munsiari Thrust?

USGS Publications Warehouse

Robinson, Delores M.; Pearson, Ofori N.

2013-01-01

The Ramgarh–Munsiari thrust is a major orogen-scale fault that extends for more than 1,500 km along strike in the Himalayan fold-thrust belt. The fault can be traced along the Himalayan arc from Himachal Pradesh, India, in the west to eastern Bhutan. The fault is located within the Lesser Himalayan tectonostratigraphic zone, and it translated Paleoproterozoic Lesser Himalayan rocks more than 100 km toward the foreland. The Ramgarh–Munsiari thrust is always located in the proximal footwall of the Main Central thrust. Northern exposures (toward the hinterland) of the thrust sheet occur in the footwall of the Main Central thrust at the base of the high Himalaya, and southern exposures (toward the foreland) occur between the Main Boundary thrust and Greater Himalayan klippen. Although the metamorphic grade of rocks within the Ramgarh–Munsiari thrust sheet is not significantly different from that of Greater Himalayan rock in the hanging wall of the overlying Main Central thrust sheet, the tectonostratigraphic origin of the two different thrust sheets is markedly different. The Ramgarh–Munsiari thrust became active in early Miocene time and acted as the roof thrust for a duplex system within Lesser Himalayan rocks. The process of slip transfer from the Main Central thrust to the Ramgarh–Munsiari thrust in early Miocene time and subsequent development of the Lesser Himalayan duplex may have played a role in triggering normal faulting along the South Tibetan Detachment system.

Development of a Thrust Stand to Meet LISA Mission Requirements

NASA Technical Reports Server (NTRS)

Willis, William D., III; Zakrzwski, Charles M.; Merkowitz, Stephen M.

2002-01-01

A thrust stand has been built to measure the force-noise produced by electrostatic micro-Newton (muN) thrusters. The LISA mission's Disturbance Reduction System (DRS) requires thrusters that are capable of producing continuous thrust levels between 1-100 muN with a resolution of 0.1 muN. The stationary force-noise produced by these thrusters must not exceed 0.1 muN/dHz in the measurement bandwidth 10(exp -4) to 1 Hz. The LISA Thrust Stand (LTS) is a torsion-balance type thrust stand designed to meet the following requirements: stationary force-noise measurements from l0( -4) to 1 Hz with 0.1 muN/dHz sensitivity, absolute thrust measurements from 1-100 muN with better than 0.1 muN resolution, and dynamic thruster response from to 10 Hz. The LTS employs a unique vertical configuration, autocollimator for angular position measurements, and electrostatic actuators that are used for dynamic pendulum control and null-mode measurements. Force-noise levels are measured indirectly by characterizing the thrust stand as a spring-mass system. The LTS was initially designed to test the indium FEEP thruster developed by the Austrian Research Center in Seibersdorf (ARCS), but can be modified for testing other thrusters of this type.

Development of A Thrust Stand to Meet LISA Mission Requirements

NASA Technical Reports Server (NTRS)

Willis, William D., III; Zakrzwski, C. M.; Bauer, Frank H. (Technical Monitor)

2002-01-01

A thrust stand has been built and tested that is capable of measuring the force-noise produced by electrostatic micro-Newton (micro-Newton) thrusters. The LISA mission's Disturbance Reduction System (DRS) requires thrusters that are capable of producing continuous thrust levels between 1-100 micro-Newton with a resolution of 0.1 micro-Newton. The stationary force-noise produced by these thrusters must not exceed 0.1 pN/4Hz in a 10 Hz bandwidth. The LISA Thrust Stand (LTS) is a torsion-balance type thrust stand designed to meet the following requirements: stationary force-noise measurements from 10(exp-4) to 1 Hz with 0.1 micro-Newton resolution, absolute thrust measurements from 1-100 micro-Newton with better than 0.1 micro-Newton resolution, and dynamic thruster response from 10(exp -4) to 10 Hz. The ITS employs a unique vertical configuration, autocollimator for angular position measurements, and electrostatic actuators that are used for dynamic pendulum control and null-mode measurements. Force-noise levels are measured indirectly by characterizing the thrust stand as a spring-mass system. The LTS was initially designed to test the indium FEEP thruster developed by the Austrian Research Center in Seibersdorf (ARCS), but can be modified for testing other thrusters of this type.

Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 2: High pressure oxidizer turbo-pump turbine end bearing analysis

NASA Technical Reports Server (NTRS)

Sisk, Gregory A.

1989-01-01

The high-pressure oxidizer turbopump (HPOTP) consists of two centrifugal pumps, on a common shaft, that are directly driven by a hot-gas turbine. Pump shaft axial thrust is balanced in that the double-entry main inducer/impeller is inherently balanced and the thrusts of the preburner pump and turbine are nearly equal but opposite. Residual shaft thrust is controlled by a self-compensating, non-rubbing, balance piston. Shaft hang-up must be avoided if the balance piston is to perform properly. One potential cause of shaft hang-up is contact between the Phase 2 bearing support and axial spring cartridge of the HPOTP main pump housing. The status of the bearing support/axial spring cartridge interface is investigated under current loading conditions. An ANSYS version 4.3, three-dimensional, finite element model was generated on Lockheed's VAX 11/785 computer. A nonlinear thermal analysis was then executed on the Marshall Space Flight Center Engineering Analysis Data System (EADS). These thermal results were then applied along with the interference fit and bolt preloads to the model as load conditions for a static analysis to determine the gap status of the bearing support/axial spring cartridge interface. For possible further analysis of the local regions of HPOTP main pump housing assembly, detailed ANSYS submodels were generated using I-DEAS Geomod and Supertab (Appendix A).

Temporal evolution of surface rupture deduced from coseismic multi-mode secondary fractures: Insights from the October 8, 2005 (Mw 7.6) Kashmir earthquake, NW Himalaya

NASA Astrophysics Data System (ADS)

Sayab, Mohammad; Khan, Muhammad Asif

2010-10-01

Detailed rupture-fracture analyses of some of the well-studied earthquakes have revealed that the geometrical arrangement of secondary faults and fractures can be used as a geological tool to understand the temporal evolution of slip produced during the mainshock. The October 8, 2005 Mw 7.6 Kashmir earthquake, NW Himalaya, surface rupture provides an opportunity to study a complex network of secondary fractures developed on the hanging wall of the fault scarp. The main fault scarp is clearly thrust-type, rupture length is ~ 75 ± 5 km and the overall trend of the rupture is NW-SE. We present the results of our detailed structural mapping of secondary faults and fractures at 1:100 scale, on the hanging wall of the southern end of the rupture in the vicinity of the Sar Pain. Secondary ruptures can be broadly classified as two main types, 1) normal faults and, (2) right-lateral strike-slip 'Riedel' fractures. The secondary normal faults are NW-SE striking, with a maximum 3.3 meter vertical displacement and 2.5 meter horizontal displacement. Estimated total horizontal extension across the secondary normal faults is 3.1-3.5%. We propose that the bending-moment and coseismic stress relaxation can explain the formation of secondary normal faults on the hanging wall of the thrust fault. The strike-slip 'Riedel' fractures form distinct sets of tension (T) and shear fractures (R', R, Y) with right-lateral displacement. Field observations revealed that the 'Riedel' fractures (T) cut the secondary normal faults. In addition, there is kinematic incompatibility and magnitude mismatch between the secondary normal faults and strike-slip 'Riedel' fractures. The cross-cutting relationship, geometric and magnitude incoherence implies a temporal evolution of slip from dip- to strike-slip during the mainshock faulting. The interpretation is consistent with the thrust fault plane solution with minor right-lateral strike-slip component.

Driving mechanisms for >40 km of exhumation during contraction and extension in a continental arc, Cascades core, Washington

USGS Publications Warehouse

Paterson, Scott R.; Miller, R.B.; Alsleben, H.; Whitney, D.L.; Valley, P.M.; Hurlow, H.

2004-01-01

In the NW North American Cordillera, the Cascades core region of the Coast Plutonic Complex underwent Late Cretaceous (>96 Ma to locally 73 Ma) SW-NE contraction and crustal thickening followed by dextral transpression (???73 to 55 Ma), then transtension (3 mm /yr) by local thrusting in regions undergoing crustal thickening. In the central part of the core (Chelan block), >40 km of exhumation occurred between 91 and 45 Ma, about half of which occurred during early contraction (driven by thrusting) and half during top-to-north, arc-oblique shear during reactivation of a midcrustal Cretaceous thrust, the Dinkelman decollement. The footwall of this thrust consists of the Swakane Biotite Gneiss, a Cretaceous, metaclastic assemblage with recorded pressures of 10-12 kbar, no arc-related magmatism, and structures dominated by pervasive top-to-north shearing. The hanging wall consists of the Napeequa Complex, an oceanic assemblage with recorded pressures of 6-12 kbar, voluminous arc-related magmatism, and complex structures indicating early top-to-WSW shearing, younger top-to-north shearing, and widespread folding. In the Napeequa, top-to-north shearing started by 73 Ma during melt-present conditions at pressures ???6 kbar. Top-to-north shearing in both hanging wall and footwall continued during exhumation (???1.6 mm/yr) and cooling to greenschist facies conditions during which slip became increasingly localized, eventually resulting in formation of pseudotachylite on discrete slip surfaces. We suggest that arc-oblique extension was driven by along-arc heterogeneity in displacements/ erosion, initially during transpression and underplating of continental sediments, and later during transtension. Copyright 2004 by the American Geophysical Union.

Physical Fitness Test Battery for Mentally Retarded Children (Trainable and Educable).

ERIC Educational Resources Information Center

Fait, Hollis F.

A physical fitness test battery for educable and trainable mentally handicapped children is presented. Instructions are given for administering the test; descriptions are given of the seven test items, including the 25 yard run, bent arm hang, leg lift, static balance, thrust, and 300 yard run-walk. Rationale for the items and factors in…

Thrust-induced collapse of mountains-an example from the "Big Bend" region of the San Andreas Fault, western transverse ranges, California

USGS Publications Warehouse

Kellogg, Karl S.

2005-01-01

Mount Pinos and Frazier Mountain are two prominent mountains just south of the San Andreas fault in the western Transverse Ranges of southern California, a region that has undergone rapid Quaternary contraction and uplift. Both mountains are underlain, at least in part, by thrusts that place granitic and gneissic rocks over sedimentary rocks as young as Pliocene. Broad profiles and nearly flat summits of each mountain have previously been interpreted as relicts of a raised erosion surface. However, several features bring this interpretation into question. First, lag or stream gravels do not mantle the summit surfaces. Second, extensive landslide deposits, mostly pre?Holocene and deeply incised, mantle the flanks of both mountains. Third, a pervasive fracture and crushed?rock network pervades the crystalline rocks underlying both mountains. The orientation of the fractures, prominent in roadcuts on Mount Pinos, is essentially random. 'Hill?and?saddle' morphology characterizes ridges radiating from the summits, especially on Mount Pinos; outcrops are sparse on the hills and are nonexistent in the saddles, suggesting fractures are concentrated in the saddles. Latest movement on the thrusts underlying the two mountain massifs is probably early Quaternary, during which the mountains were uplifted to considerably higher (although unknown) elevations than at present. A model proposes that during thrusting, ground accelerations in the hanging wall, particularly near thrust tips, were high enough to pervasively fracture the hanging?wall rocks, thereby weakening them and producing essentially an assemblage of loose blocks. Movement over flexures in the fault surface accentuated fracturing. The lowered shear stresses necessary for failure, coupled with deep dissection and ongoing seismic activity, reduced gravitational potential by spreading the mountain massifs, triggering flanking landslides and producing broad, flat?topped mountains. This study developed from mapping in the western Transverse Ranges as part of the U.S. Geological Survey's Southern California Areal Mapping Project (SCAMP).

Performance characterization of a permanent-magnet helicon plasma thruster

NASA Astrophysics Data System (ADS)

Takahashi, Kazunori; Charles, Christine; Boswell, Rod

2012-10-01

Helicon plasma thrusters operated at a few kWs of rf power is an active area of an international research. Recent experiments have clarified part of the thrust-generation mechanisms. Thrust components which have been identified include an electron pressure inside the source region and a Lorentz force due to an electron diamagnetic drift current and a radial component of the applied magnetic field. The use of permanent magnets (PMs) instead of solenoids is one of the solutions for improving the thruster efficiency because it does not require electricity for the magnetic nozzle formation. Here the thrust imparted from a permanent-magnet helicon plasma thruster is directly measured using a pendulum thrust balance. The source consists of permanent magnet (PM) arrays, a double turn rf loop antenna powered by a 13.56 MHz rf generator and a glass source tube. The PM arrays provide a magnetic nozzle near the open exit of the source and two configurations, which have maximum field strengths of about 100 and 270 G, are tested. A thrust of 15 mN, specific impulse of 2000 sec and a thrust efficiency of 8 percent are presently obtained for 2 kW of input power, 24 sccm flow rate of argon and the stronger magnetic field configuration.

Width of surface rupture zone for thrust earthquakes: implications for earthquake fault zoning

NASA Astrophysics Data System (ADS)

Boncio, Paolo; Liberi, Francesca; Caldarella, Martina; Nurminen, Fiia-Charlotta

2018-01-01

The criteria for zoning the surface fault rupture hazard (SFRH) along thrust faults are defined by analysing the characteristics of the areas of coseismic surface faulting in thrust earthquakes. Normal and strike-slip faults have been deeply studied by other authors concerning the SFRH, while thrust faults have not been studied with comparable attention. Surface faulting data were compiled for 11 well-studied historic thrust earthquakes occurred globally (5.4 ≤ M ≤ 7.9). Several different types of coseismic fault scarps characterize the analysed earthquakes, depending on the topography, fault geometry and near-surface materials (simple and hanging wall collapse scarps, pressure ridges, fold scarps and thrust or pressure ridges with bending-moment or flexural-slip fault ruptures due to large-scale folding). For all the earthquakes, the distance of distributed ruptures from the principal fault rupture (r) and the width of the rupture zone (WRZ) were compiled directly from the literature or measured systematically in GIS-georeferenced published maps. Overall, surface ruptures can occur up to large distances from the main fault ( ˜ 2150 m on the footwall and ˜ 3100 m on the hanging wall). Most of the ruptures occur on the hanging wall, preferentially in the vicinity of the principal fault trace ( > ˜ 50 % at distances < ˜ 250 m). The widest WRZ are recorded where sympathetic slip (Sy) on distant faults occurs, and/or where bending-moment (B-M) or flexural-slip (F-S) fault ruptures, associated with large-scale folds (hundreds of metres to kilometres in wavelength), are present. A positive relation between the earthquake magnitude and the total WRZ is evident, while a clear correlation between the vertical displacement on the principal fault and the total WRZ is not found. The distribution of surface ruptures is fitted with probability density functions, in order to define a criterion to remove outliers (e.g. 90 % probability of the cumulative distribution function) and define the zone where the likelihood of having surface ruptures is the highest. This might help in sizing the zones of SFRH during seismic microzonation (SM) mapping. In order to shape zones of SFRH, a very detailed earthquake geologic study of the fault is necessary (the highest level of SM, i.e. Level 3 SM according to Italian guidelines). In the absence of such a very detailed study (basic SM, i.e. Level 1 SM of Italian guidelines) a width of ˜ 840 m (90 % probability from "simple thrust" database of distributed ruptures, excluding B-M, F-S and Sy fault ruptures) is suggested to be sufficiently precautionary. For more detailed SM, where the fault is carefully mapped, one must consider that the highest SFRH is concentrated in a narrow zone, ˜ 60 m in width, that should be considered as a fault avoidance zone (more than one-third of the distributed ruptures are expected to occur within this zone). The fault rupture hazard zones should be asymmetric compared to the trace of the principal fault. The average footwall to hanging wall ratio (FW : HW) is close to 1 : 2 in all analysed cases. These criteria are applicable to "simple thrust" faults, without considering possible B-M or F-S fault ruptures due to large-scale folding, and without considering sympathetic slip on distant faults. Areas potentially susceptible to B-M or F-S fault ruptures should have their own zones of fault rupture hazard that can be defined by detailed knowledge of the structural setting of the area (shape, wavelength, tightness and lithology of the thrust-related large-scale folds) and by geomorphic evidence of past secondary faulting. Distant active faults, potentially susceptible to sympathetic triggering, should be zoned as separate principal faults. The entire database of distributed ruptures (including B-M, F-S and Sy fault ruptures) can be useful in poorly known areas, in order to assess the extent of the area within which potential sources of fault displacement hazard can be present. The results from this study and the database made available in the Supplement can be used for improving the attenuation relationships for distributed faulting, with possible applications in probabilistic studies of fault displacement hazard.

Tectonic controls on large landslide complex: Williams Fork Mountains near Dillon, Colorado

USGS Publications Warehouse

Kellogg, K.S.

2001-01-01

An extensive (~ 25 km2) landslide complex covers a large area on the west side of the Williams Fork Mountains in central Colorado. The complex is deeply weathered and incised, and in most places geomorphic evidence of sliding (breakaways, hummocky topography, transverse ridges, and lobate distal zones) are no longer visible, indicating that the main mass of the slide has long been inactive. However, localized Holocene reactivation of the landslide deposits is common above the timberline (at about 3300 m) and locally at lower elevations. Clasts within the complex, as long as several tens of meters, are entirely of crystalline basement (Proterozoic gneiss and granitic rocks) from the hanging wall of the Laramide (Late Cretaceous to Early Tertiary), west-directed Williams Range thrust, which forms the western structural boundary of the Colorado Front Range. Late Cretaceous shale and sandstone compose most footwall rocks. The crystalline hanging-wall rocks are pervasively fractured or shattered, and alteration to clay minerals is locally well developed. Sackung structures (trenches or small-scale grabens and upslope-facing scarps) are common near the rounded crest of the range, suggesting gravitational spreading of the fractured rocks and oversteepening of the mountain flanks. Late Tertiary and Quaternary incision of the Blue River Valley, just west of the Williams Fork Mountains, contributed to the oversteepening. Major landslide movement is suspected during periods of deglaciation when abundant meltwater increased pore-water pressure in bedrock fractures. A fault-flexure model for the development of the widespread fracturing and weakening of the Proterozoic basement proposes that the surface of the Williams Range thrust contains a concave-downward flexure, the axis of which coincides approximately with the contact in the footwall between Proterozoic basement and mostly Cretaceous rocks. Movement of brittle, hanging-wall rocks through the flexure during Laramide deformation pervasively fractured the hanging-wall rocks. ?? 2001 Elsevier Science B.V. All rights reserved.

The Chunky Gal Mountain fault-detachment-normal fault providing evidence for Early-to-Middle Paleozoic extensional unroofing of the eastern Blue Ridge, or folded thrust

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatcher, R.D. Jr.

1993-03-01

The Chunky Gal Mountain fault (CGMF), located in the western Blue Ridge of southern NC and northern GA, contains unequivocal evidence for hanging wall-down-to-the-west movement. The 50 m-thick fault zone here consists of a series of shear zones in the footwall in a mass of mylonitized garnet-rich biotite gneiss. The main contact with the hanging wall reveals both a contrast in rock type and truncation of fabrics. Above the fault are amphibolite, ultramafic rocks, and minor metasandstone and pelitic schist of the Buck Creek mafic-ultramafic complex, while the footwall contains complexly folded metasandstone, pelitic schist, and calcsilicate pods of themore » Coleman River Formation. In the present orientation, the mylonitic foliation in the footwall rocks of the GGMF is subvertical; foliation in the hanging wall is subhorizontal at road level. These rocks were metamorphosed to upper amphibolite facies assemblages, and, after emplacement of the CGMF, were cut by brittle faults and trondhjemite dikes that contain no obvious tectonic fabric. Movement on the CGMF occurred near the thermal peak because enough heat remained in the rocks after movement to statically anneal the mylonite microfabric, but mesoscopic rotated porphyroclasts, rotated (dragged) earlier foliation, and some S-C fabrics clearly indicate the shear sense and vergence of this structure. Shear zones related to the CGMF transposed earlier fabrics, although some relicts preserving earlier structures remain in the shear zones. These rotated but untransposed relicts of amphibolite and garnet-rich biotite gneiss mylonite may indicate locally higher strain rates in subsidiary shear zones. The thermal/mechanical properties of the CGMF make it difficult to connect to the Shope Fork or Soque River thrusts farther south and east. Thus the hanging-wall-down configuration provides an alternative hypothesis that the CGMF may be a detachment-normal fault related to Taconian extensional unroofing of the Appalachians.« less

The Air Force Phillips Laboratory multimegawatt quasi-steady MPD thruster facility

NASA Astrophysics Data System (ADS)

Castillo, Salvador; Tilley, Dennis L.

1992-07-01

The operational multimegawatt quasi-steady MPD thruster facility is described in terms of its general design emphasizing the impulse thrust stand and diagnostics capabilities. The vacuum, propellant, and electrical systems are discussed with schematic diagrams of the respective component configurations and explanations of the needs of MPD thruster testing. The impulse thrust stand comprises an accelerometer/pendulum-impulse stand which can be used to correlate thruster impulse with accelerometer readings and thereby reduce measurement uncertainties. The diagnostics of the terminal characteristics of the thruster operation are complemented by diagnostics platforms that study plasma properties in the plume and the thruster. Preliminary tests indicate that the MPD thruster facility is prepared for detailed investigations of MPD thruster performance and plume diagnostics.

Laser-Driven Mini-Thrusters

NASA Astrophysics Data System (ADS)

Sterling, Enrique; Lin, Jun; Sinko, John; Kodgis, Lisa; Porter, Simon; Pakhomov, Andrew V.; Larson, C. William; Mead, Franklin B.

2006-05-01

Laser-driven mini-thrusters were studied using Delrin® and PVC (Delrin® is a registered trademark of DuPont) as propellants. TEA CO2 laser (λ = 10.6 μm) was used as a driving laser. Coupling coefficients were deduced from two independent techniques: force-time curves measured with a piezoelectric sensor and ballistic pendulum. Time-resolved ICCD images of the expanding plasma and combustion products were analyzed in order to determine the main process that generates the thrust. The measurements were also performed in a nitrogen atmosphere in order to test the combustion effects on thrust. A pinhole transmission experiment was performed for the study of the cut-off time when the ablation/air breakdown plasma becomes opaque to the incoming laser pulse.

Fluid-rock interactions related to metamorphic reducing fluid flow in meta-sediments: example of the Pic-de-Port-Vieux thrust (Pyrenees, Spain)

NASA Astrophysics Data System (ADS)

Trincal, Vincent; Buatier, Martine; Charpentier, Delphine; Lacroix, Brice; Lanari, Pierre; Labaume, Pierre; Lahfid, Abdeltif; Vennemann, Torsten

2017-09-01

In orogens, shortening is mainly accommodated by thrusts, which constitute preferential zones for fluid-rock interactions. Fluid flow, mass transfer, and mineralogical reactions taking place along thrusts have been intensely investigated, especially in sedimentary basins for petroleum and uranium research. This study combines petrological investigations, mineralogical quantifications, and geochemical characterizations with a wide range of analytical tools with the aim of defining the fluid properties (nature, origin, temperature, and redox) and fluid-host rock interactions (mass transfers, recrystallization mechanisms, and newly formed synkinematic mineralization) in the Pic-de-Port-Vieux thrust fault zone (Pyrenees, Spain). We demonstrate that two geochemically contrasted rocks have been transformed by fluid flow under low-grade metamorphism conditions during thrusting. The hanging-wall Triassic red pelite was locally bleached, while the footwall Cretaceous dolomitic limestone was mylonitized. The results suggest that thrusting was accompanied by a dynamic calcite recrystallization in the dolomitic limestone as well as by leaching of iron via destabilization of iron oxides and phyllosilicate crystallization in the pelite. Geochemical and physical changes highlighted in this study have strong implications on the understanding of the thrust behavior (tectonic and hydraulic), and improve our knowledge of fluid-rock interactions in open fluid systems in the crust.

Development of a Transient Thrust Stand with Sub-Millisecond Resolution

NASA Astrophysics Data System (ADS)

Spells, Corbin Fraser

The transient thrust stand has been developed to offer 0.1 ms time resolved thrust measurements for the characterization of mono-propellant thrusters for spacecraft applications. Results demonstrated that the system was capable of obtaining dynamic thrust profiles within 5 % and 0.1 ms. Measuring and improving the thrust performance of mono-propellant thrusters will require 1 ms time resolved forces to observe shot-to-shot variations, oscillations, and minimum impulse bits. To date, no thrust stand is capable of measuring up to 22 N forces with a time response of up to 10 kHz. Calibration forces up to 22 N with a frequency response greater than 0.1 ms were obtained using voice coil actuators. Steady state and low frequency measurements were obtained using displacement and velocity sensors and were combined with high frequency vibration modes measured using several accelerometers along the thrust stand arm. The system uses a predictor-based subspace algorithm to obtain a high order state space model of the thrust stand capable of defining the high frequency vibration modes. The high frequency vibration modes are necessary to provide the time response of 0.1 ms. Thruster forces are estimated using an augmented Kalman filter to combine sensor traces from four accelerometers, a velocity sensor, and displacement transducer. Combining low frequency displacement data with high frequency acceleration measurements provides accurate force data across a broad time domain. The transient thrust stand uses a torsional pendulum configuration to minimize influence from external vibration and achieve high force resolution independent of thruster weight.

Operating a magnetic nozzle helicon thruster with strong magnetic field

NASA Astrophysics Data System (ADS)

Takahashi, Kazunori; Komuro, Atsushi; Ando, Akira

2016-03-01

A pulsed axial magnetic field up to ˜2.8 kG is applied to a 26-mm-inner-diameter helicon plasma thruster immersed in a vacuum chamber, and the thrust is measured using a pendulum target. The pendulum is located 30-cm-downstream of the thruster, and the thruster rf power and argon flow rate are fixed at 1 kW and 70 sccm (which gives a chamber pressure of 0.7 mTorr). The imparted thrust increases as the applied magnetic field is increased and saturates at a maximum value of ˜9.5 mN for magnetic field above ˜2 kG. At the maximum magnetic field, it is demonstrated that the normalized plasma density, and the ion flow energy in the magnetic nozzle, agree within ˜50% and of 10%, respectively, with a one-dimensional model that ignores radial losses from the nozzle. This magnetic nozzle model is combined with a simple global model of the thruster source that incorporates an artificially controlled factor α, to account for radial plasma losses to the walls, where α = 0 and 1 correspond to zero losses and no magnetic field, respectively. Comparison between the experiments and the model implies that the radial losses in the thruster source are experimentally reduced by the applied magnetic field to about 10% of that obtained from the no magnetic field model.

How far can Tarzan jump?

NASA Astrophysics Data System (ADS)

Shima, Hiroyuki

2012-11-01

The tree-based rope swing is a popular recreational facility, often installed in outdoor areas. Hanging from a rope, users drop from a high platform and then swing at great speed like ‘Tarzan’, finally jumping ahead to land on the ground. The question naturally arises, how far can Tarzan jump using the swing? In this paper, I present an introductory analysis of the mechanics of the Tarzan swing, a large pendulum-like swing with Tarzan himself attached as weight. This enables determination of how much further forward Tarzan can jump using a given swing apparatus. The discussion is based on elementary mechanics and is, therefore, expected to provide rich opportunities for investigations using analytic and numerical methods.

The Electrostatic Gavimeter: An Alternative Way of Measuring Gravitational Acceleration

NASA Astrophysics Data System (ADS)

Kashinski, David

2005-03-01

In the past, Earth’s gravitational acceleration g has been measured in many ways, including the use of a pendulum as well as other models involving the use of a mass and a spring. We have designed a new method incorporating a spring with a capacitor and a voltmeter. This capacitor model still uses a hanging mass on a spring, but alters the method of determining the change in position of the spring due to the gravitational acceleration. We relate the change in position to the potential difference across the capacitor needed to cause a discharge through parallel plates. By relating this voltage directly to the gravitaional acceleration,a new method of measuring g is obtained.

Strain partitioning in the footwall of the Somiedo Nappe: structural evolution of the Narcea Tectonic Window, NW Spain

NASA Astrophysics Data System (ADS)

Gutiérrez-Alonso, Gabriel

1996-10-01

The Somiedo Nappe is a major thrust unit in the Cantabrian Zone, the external foreland fold and thrust belt of the North Iberian Variscan orogen. Exposed at the Narcea Tectonic Window are Precambrian rocks below the basal decollement of the Somiedo Nappe, which exhibit a different deformation style than the overlying Paleozoic rocks above the basal decollement. During Variscan deformation, folding and widespread subhorizontal, bedding-parallel decollements were produced in the hanging wall within the Paleozoic rocks. Vertical folding, with related axial-planar cleavage at a high angle to the decollement planes, developed simultaneously in the upper Proterozoic Narcea Slates of the footwall, below the detachment. The relative magnitude of finite strain, measured in the footwall rocks, diminishes towards the foreland. These observations indicate that (1) significant deformation may occur in the footwall of foreland fold and thrust belts, (2) the shortening mechanism in the footwall may be different from that of the hanging wall, and (3) in this particular case, the partitioning of the deformation implies the existence of a deeper, blind decollement surface contemporaneous with the first stages of the foreland development, that does not crop out in the region. This implies a significant shortening in the footwall, which must be taken into account when restoration and balancing of cross-sections is attempted. A sequential diagram of the evolution of the Narcea Tectonic Window with a minimum shortening of 85 km is proposed, explaining the complete Variscan evolution of the foreland to hinterland transition in the North Iberian Variscan orogen.

Structural analysis of the Gachsar sub-zone in central Alborz range; constrain for inversion tectonics followed by the range transverse faulting

NASA Astrophysics Data System (ADS)

Yassaghi, A.; Naeimi, A.

2011-08-01

Analysis of the Gachsar structural sub-zone has been carried out to constrain structural evolution of the central Alborz range situated in the central Alpine Himalayan orogenic system. The sub-zone bounded by the northward-dipping Kandovan Fault to the north and the southward-dipping Taleghan Fault to the south is transversely cut by several sinistral faults. The Kandovan Fault that controls development of the Eocene rocks in its footwall from the Paleozoic-Mesozoic units in the fault hanging wall is interpreted as an inverted basin-bounding fault. Structural evidences include the presence of a thin-skinned imbricate thrust system propagated from a detachment zone that acts as a footwall shortcut thrust, development of large synclines in the fault footwall as well as back thrusts and pop-up structures on the fault hanging wall. Kinematics of the inverted Kandovan Fault and its accompanying structures constrain the N-S shortening direction proposed for the Alborz range until Late Miocene. The transverse sinistral faults that are in acute angle of 15° to a major magnetic lineament, which represents a basement fault, are interpreted to develop as synthetic Riedel shears on the cover sequences during reactivation of the basement fault. This overprinting of the transverse faults on the earlier inverted extensional fault occurs since the Late Miocene when the south Caspian basin block attained a SSW movement relative to the central Iran. Therefore, recent deformation in the range is a result of the basement transverse-fault reactivation.

How to predict deformation for geometrically and mechanically non-uniform accretionary wedges

NASA Astrophysics Data System (ADS)

Souloumiac, Pauline; Cubas, Nadaya; Caër, Typhaine

2017-04-01

The mechanical understanding of fold-and-thrust belts and accretionary prisms strongly relies on the critical taper theory (CTT). The latter considers their mechanics as analogous to sand pushed by a moving bulldozer along a frictional décollement. The wedge evolves into a critical geometry, corresponding to a point of internal state of stress for which the whole wedge including the basal décollement is on the verge of Coulomb failure. If the décollement is planar and material properties are homogeneous and cohesionless, the critical wedge is triangular. The force of the CCT relies on the fact that conditions for stress equilibrium, Coulomb yielding of the wedge and basal frictional sliding have an analytical solution. However, this theory suffers from several limits. As stated above, the analytical solution applies for perfectly triangular wedges. However, the critical taper is shaped by internal thrusts that lead to a non-uniform topographic slope. What is then the scale of topographic variability for which the CCT will stand? The second limit is that CCT applies for homogeneous frictional properties in the wedge and as well as along the décollement. We can also wonder if there is a scaling parameter for which variations of properties along the decollement would impact the topography. We here show how the limit analysis, an efficient semi-analytical approach, can help us to overcome these limits. We aim to provide simple analytical solutions to structural geologists to evaluate the critical state of their field study cases. We first show that the effect of topographic slope variability relies on a competition between the surface of potential hanging-walls and the surface of theoretical critical hanging-walls. Dips of thrust and backthrust are controlled by the frictional parameters. Along a wedge with a non-regular topography, an out-of-sequence system will appear if there is a position along the wedge for which the hanging-wall will have a lower surface than the critical one. The impact of basal friction variations on the topography can be resolve in the same manner but by comparing force balances and not only surfaces. To validate our findings, analytical solutions are compared to sandbox experiments. We will also compare our results to natural cases such as the Jura (France) fold-and-thrust belt. Finally, we will discuss how the same approach can be applied to variations of the décollement geometry.

Exploring the shallow structure of the San Ramón thrust fault in Santiago, Chile (~33.5° S), using active seismic and electric methods

NASA Astrophysics Data System (ADS)

Díaz, D.; Maksymowicz, A.; Vargas, G.; Vera, E.; Contreras-Reyes, E.; Rebolledo, S.

2014-08-01

The crustal-scale west-vergent San Ramón thrust fault system, which lies at the foot of the main Andean Cordillera in central Chile, is a geologically active structure with manifestations of late Quaternary complex surface rupture on fault segments along the eastern border of the city of Santiago. From the comparison of geophysical and geological observations, we assessed the subsurface structural pattern that affects the sedimentary cover and rock-substratum topography across fault scarps, which is critical for evaluating structural models and associated seismic hazard along the related faults. We performed seismic profiles with an average length of 250 m, using an array of 24 geophones (Geode), with 25 shots per profile, to produce high-resolution seismic tomography to aid in interpreting impedance changes associated with the deformed sedimentary cover. The recorded travel-time refractions and reflections were jointly inverted by using a 2-D tomographic approach, which resulted in variations across the scarp axis in both the velocities and the reflections that are interpreted as the sedimentary cover-rock substratum topography. Seismic anisotropy observed from tomographic profiles is consistent with sediment deformation triggered by west-vergent thrust tectonics along the fault. Electrical soundings crossing two fault scarps were used to construct subsurface resistivity tomographic profiles, which reveal systematic differences between lower resistivity values in the hanging wall with respect to the footwall of the geological structure, and clearly show well-defined east-dipping resistivity boundaries. These boundaries can be interpreted in terms of structurally driven fluid content change between the hanging wall and the footwall of the San Ramón fault. The overall results are consistent with a west-vergent thrust structure dipping ~55° E in the subsurface beneath the piedmont sediments, with local complexities likely associated with variations in fault surface rupture propagation, fault splays and fault segment transfer zones.

Exploring the shallow structure of the San Ramón thrust fault in Santiago, Chile (∼33.5° S), using active seismic and electric methods

NASA Astrophysics Data System (ADS)

Díaz, D.; Maksymowicz, A.; Vargas, G.; Vera, E.; Contreras-Reyes, E.; Rebolledo, S.

2014-01-01

The crustal-scale west-vergent San Ramón thrust fault system at the foot of the main Andean Cordillera in central Chile is a geologically active structure with Quaternary manifestations of complex surface rupture along fault segments in the eastern border of Santiago city. From the comparison of geophysical and geological observations, we assessed the subsurface structure pattern affecting sedimentary cover and rock-substratum topography across fault scarps, which is critic for evaluating structural modeling and associated seismic hazard along this kind of faults. We performed seismic profiles with an average length of 250 m, using an array of twenty-four geophones (GEODE), and 25 shots per profile, supporting high-resolution seismic tomography for interpreting impedance changes associated to deformed sedimentary cover. The recorded traveltime refractions and reflections were jointly inverted by using a 2-D tomographic approach, which resulted in variations across the scarp axis in both velocities and reflections interpreted as the sedimentary cover-rock substratum topography. Seismic anisotropy observed from tomographic profiles is consistent with sediment deformation triggered by west-vergent thrust tectonics along the fault. Electrical soundings crossing two fault scarps supported subsurface resistivity tomographic profiles, which revealed systematic differences between lower resistivity values in the hanging wall with respect to the footwall of the geological structure, clearly limited by well-defined east-dipping resistivity boundaries. The latter can be interpreted in terms of structurally driven fluid content-change between the hanging wall and the footwall of a permeability boundary associated with the San Ramón fault. The overall results are consistent with a west-vergent thrust structure dipping ∼55° E at subsurface levels in piedmont sediments, with local complexities being probably associated to fault surface rupture propagation, fault-splay and fault segment transfer zones.

Ultra-Stable Beacon Source for Laboratory Testing of Optical Tracking

NASA Technical Reports Server (NTRS)

Aso, Yoichi; Marka, Szabolcs; Kovalik, Joseph

2008-01-01

The ultra-stable beacon source (USBS) provides a laser-beam output with a very low angular jitter and can be used as an absolute angular reference to simulate a beacon in the laboratory. The laser is mounted on the top of a very short (approximately equal to 1 m) inverted pendulum (IP) with its optical axis parallel to the carbon fiber pendulum leg. The 85-cm, carbon fiber rods making up the leg are very lightweight and rigid, and are supported by a flex-joint at the bottom (see figure). The gimbal-mounted laser is a weight-adjustable load of about 1.5 kg with its center of rotation co-located with the center of percussion of the inverted pendulum. This reduces the coupling of transverse motion at the base of the pendulum to angular motion of the laser at the top. The inverted pendulum is mounted on a gimbal with its center of rotation coinciding with the pivot position of the inverted pendulum flexure joint. This reduces coupling of ground tilt at the inverted pendulum base to motion of the laser mounted at the top. The mass of the top gimbal is adjusted to give the pendulum a very low resonant frequency (approximately equal to 10 mHz) that filters transverse seismic disturbances from the ground where the base is attached. The motion of the IP is monitored by an optical-lever sensor. The laser light is reflected by the mirror on the IP, and then is detected by a quadrant photo-detector (QPD). The position of the beam spot on the QPD corresponds to the tilt of the IP. Damping of this motion is provided by two coil and magnet pairs. The bottom gimbal mount consists of two plates. The IP is mounted on the second plate. The first plate is supported by two posts through needles and can be rotated about the axis connecting the tips of the needles. The second plate hangs from the first plate and can be rotated about the axis perpendicular to the first plate. As a result, the second plate acts as a two-axis rotation stage. Its center of rotation is located at the effective bending point of the flex-joint. The second plate is pressed against two screw actuators by the weight of the IP. The screw actuators are orthogonal to each other and are used to adjust the inclination of the second plate. The actuators are driven by stepper motors. The whole IP system is housed in a box made of Lexan plastic plates to provide isolation from air currents and temperature variations. The signals from the sensors are processed and recorded with a PC using the xPC Target realtime environment of Math- Works. The control algorithms are written using the Simulink package from The MathWorks.

Experimental investigation of a unique airbreathing pulsed laser propulsion concept

NASA Technical Reports Server (NTRS)

Myrabo, L. N.; Nagamatsu, H. T.; Manka, C.; Lyons, P. W.; Jones, R. A.

1991-01-01

Investigations were conducted into unique methods of converting pulsed laser energy into propulsive thrust across a flat impulse surface under atmospheric conditions. The propulsion experiments were performed with a 1-micron neodymium-glass laser at the Space Plasma Branch of the Naval Research Laboratory. Laser-induced impulse was measured dynamically by ballistic pendulums and statically using piezoelectric pressure transducers on a stationary impulse surface. The principal goal was to explore methods for increasing the impulse coupling performance of airbreathing laser-propulsion engines. A magnetohydrodynamic thrust augmentation effect was discovered when a tesla-level magnetic field was applied perpendicular to the impulse surface. The impulse coupling coefficient performance doubled and continued to improve with increasing laser-pulse energies. The resultant performance of 180 to 200 N-s/MJ was found to be comparable to that of the earliest afterburning turbojets.

Operating a magnetic nozzle helicon thruster with strong magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, Kazunori, E-mail: kazunori@ecei.tohoku.ac.jp; Komuro, Atsushi; Ando, Akira

A pulsed axial magnetic field up to ∼2.8 kG is applied to a 26-mm-inner-diameter helicon plasma thruster immersed in a vacuum chamber, and the thrust is measured using a pendulum target. The pendulum is located 30-cm-downstream of the thruster, and the thruster rf power and argon flow rate are fixed at 1 kW and 70 sccm (which gives a chamber pressure of 0.7 mTorr). The imparted thrust increases as the applied magnetic field is increased and saturates at a maximum value of ∼9.5 mN for magnetic field above ∼2 kG. At the maximum magnetic field, it is demonstrated that the normalized plasma density, and the ionmore » flow energy in the magnetic nozzle, agree within ∼50% and of 10%, respectively, with a one-dimensional model that ignores radial losses from the nozzle. This magnetic nozzle model is combined with a simple global model of the thruster source that incorporates an artificially controlled factor α, to account for radial plasma losses to the walls, where α = 0 and 1 correspond to zero losses and no magnetic field, respectively. Comparison between the experiments and the model implies that the radial losses in the thruster source are experimentally reduced by the applied magnetic field to about 10% of that obtained from the no magnetic field model.« less

Initiation of a thrust fault revealed by analog experiments

NASA Astrophysics Data System (ADS)

Dotare, Tatsuya; Yamada, Yasuhiro; Adam, Juergen; Hori, Takane; Sakaguchi, Hide

2016-08-01

To reveal in detail the process of initiation of a thrust fault, we conducted analog experiments with dry quartz sand using a high-resolution digital image correlation technique to identify minor shear-strain patterns for every 27 μm of shortening (with an absolute displacement accuracy of 0.5 μm). The experimental results identified a number of "weak shear bands" and minor uplift prior to the initiation of a thrust in cross-section view. The observations suggest that the process is closely linked to the activity of an adjacent existing thrust, and can be divided into three stages. Stage 1 is characterized by a series of abrupt and short-lived weak shear bands at the location where the thrust will subsequently be generated. The area that will eventually be the hanging wall starts to uplift before the fault forms. The shear strain along the existing thrust decreases linearly during this stage. Stage 2 is defined by the generation of the new thrust and active displacements along it, identified by the shear strain along the thrust. The location of the new thrust may be constrained by its back-thrust, generally produced at the foot of the surface slope. The activity of the existing thrust falls to zero once the new thrust is generated, although these two events are not synchronous. Stage 3 of the thrust is characterized by a constant displacement that corresponds to the shortening applied to the model. Similar minor shear bands have been reported in the toe area of the Nankai accretionary prism, SW Japan. By comparing several transects across this subduction margin, we can classify the lateral variations in the structural geometry into the same stages of deformation identified in our experiments. Our findings may also be applied to the evaluation of fracture distributions in thrust belts during unconventional hydrocarbon exploration and production.

A comprehensive cold gas performance study of the Pocket Rocket radiofrequency electrothermal microthruster

NASA Astrophysics Data System (ADS)

Ho, Teck Seng; Charles, Christine; Boswell, Roderick W.

2016-12-01

This paper presents computational fluid dynamics simulations of the cold gas operation of Pocket Rocket and Mini Pocket Rocket radiofrequency electrothermal microthrusters, replicating experiments performed in both sub-Torr and vacuum environments. This work takes advantage of flow velocity choking to circumvent the invalidity of modelling vacuum regions within a CFD simulation, while still preserving the accuracy of the desired results in the internal regions of the microthrusters. Simulated results of the plenum stagnation pressure is in precise agreement with experimental measurements when slip boundary conditions with the correct tangential momentum accommodation coefficients for each gas are used. Thrust and specific impulse is calculated by integrating the flow profiles at the exit of the microthrusters, and are in good agreement with experimental pendulum thrust balance measurements and theoretical expectations. For low thrust conditions where experimental instruments are not sufficiently sensitive, these cold gas simulations provide additional data points against which experimental results can be verified and extrapolated. The cold gas simulations presented in this paper will be used as a benchmark to compare with future plasma simulations of the Pocket Rocket microthruster.

Multiply charged ion generation according to magnetic field configurations in Hall thruster plasmas

NASA Astrophysics Data System (ADS)

Kim, Holak; Lee, Seunghun; Kim, Junbum; Lim, Youbong; Choe, Wonho; KIMS Collaboration

2016-09-01

Plasma propulsion is the most promising techniques to operate satellites for low earth orbit as well as deep space exploration. A typical plasma propulsion system is Hall thruster (HT) that uses crossed electromagnetic fields to ionize a propellant gas and to accelerate the ionized gas. In HT the tailoring of magnetic fields is significant due to that the electron confinement in the electromagnetic fields affects thruster performances such as thrust force, specific impulse, power efficiency, and life time. We designed an anode layer HT (TAL) with the magnetic field tailoring. The TAL is possible to keep discharge in 1 2 kilovolts, which voltage is useful to obtain high specific impulse The magnetic field tailoring is adapted to minimize undesirable heat dissipations and secondary electron emissions at a wall surrounding plasma In presentation, we will report TAL performances including thrust force, specific impulse, and anode efficiency measured by a pendulum thrust stand. This mechanical measurement will be compared to the plasma diagnostics conducted by angular Faraday probe, retarding potential analyzer, and ExB probe Grant No. 2014M1A3A3A02034510.

Geologic map of the Lockwood Valley Quadrangle, Ventura County, California

USGS Publications Warehouse

Kellogg, Karl S.

2001-01-01

The Lockwood Valley quadrangle is located in the western Transverse Ranges of California, about 10 km southwest of Frazier Park. It includes the western flank of Frazier Mountain, southern Lockwood Valley, and a region of the Los Padres National Forest near northern Piru Creek. The oldest rocks are mostly biotite augen gneiss, in the hanging wall of the Frazier Mountain thrust and in a large body south of the thrust. A U-Pb zircon age for the gneiss is 1690+5 Ma (W. Premo, unpublished data). Two Cretaceous intrusive rocks are named the quartz monzonite of Sheep Creek and the coarse-grained granodiorite of Lockwood Peak. A U-Pb zircon age on the latter is 76.05+0.22 Ma (W. Premo, unpublished data). The northeastern edge of a large Eocene marine basin, comprising the sandstones, shales, and conglomerates of the Juncal Formation, occupies the southwestern 25 percent of the quadrangle. Miocene fluvial rocks, including coarse boulder conglomerates, sandstones, and shale, of the Caliente Formation crop out mostly in the northwestern part of the quadrangle. Commercially exploitable Lockwood Clay unconformably overlies the Caliente, which, in turn, is overlain by the mostly fluvial Pliocene Quatal Formation. Two major south-directed thrusts, the Frazier Mountain thrust and the South Frazier Mountain thrust, place crystalline rocks over Miocene and Pliocene sedimentary rocks. The South Frazier Mountain thrust is transected by the newly recognized, north-directed Lockwood Peak reverse fault. In addition, the newly recognized south-directed Yellowjacket thrust displaces rocks of the Pliocene Quatal Formation.

Focused exhumation along megathrust splay faults in Prince William Sound, Alaska

NASA Astrophysics Data System (ADS)

Haeussler, P. J.; Armstrong, P. A.; Liberty, L. M.; Ferguson, K.; Finn, S.; Arkle, J. C.; Pratt, T. L.

2011-12-01

Megathrust splay faults have been identified as important for generating tsunamis in some subduction zone earthquakes (1946 Nankai, 1964 Alaska, 2004 Sumatra). The larger role of megathrust splay faults in accretionary prisms is not well known. In Alaska, we have new evidence that megathrust splay faults are conduits for focused exhumation. In the southern Alaska accretionary complex, in the Prince William Sound region above the 1964 M9.2 earthquake rupture, apatite (U-Th)/He (AHe) ages, with closure temperatures of about 65°C, are typically in the range of 10-20 Ma. These relatively old ages indicate little to no accumulation of permanent strain during the megathrust earthquake cycle. However, the youngest AHe ages in all of Prince William Sound are from Montague Island, with two ages of 1.4 Ma on the southwest part of the island and two ages of 4 Ma at the northeast end of the island. Montague Island lies in the hanging wall of the Patton Bay megathrust splay fault, which ruptured during the 1964 earthquake, and resulted in 9 m of vertical uplift. Two other megathrust splay faults also ruptured during the 1964 earthquake in the same area. New high-resolution bathymetry and seismic reflection profiles show abundant normal faults in the region adjacent and north of the megathrust splay faults. The largest of these is the Montague Strait fault, which has 80 m of post glacial offset (~12kya?). We interpret this extension in the hanging wall as accommodating the exhumation of the rocks on Montague Island along the megathrust splay faults. An examination of legacy seismic reflection profiles shows the megathrust splay faults rooting downward into the decollement. At least some extension in the hanging wall may also be related to thrusting over a ramp-flat geometry. These megathrust splay faults are out of sequence thrusts, as they are located about 130 km inboard from the trench. This out of sequence thrusting that is causing the exhumation on Montague Island may be driven by underplating or by the Yakutat microplate collision. We suggest that rapid exhumation along megathrust splay faults, in association with normal faulting, may be a feature along other megathrust splay faults around the world.

Using U-Th-Pb petrochronology to determine rates of ductile thrusting: Time windows into the Main Central Thrust, Sikkim Himalaya

NASA Astrophysics Data System (ADS)

Mottram, Catherine M.; Parrish, Randall R.; Regis, Daniele; Warren, Clare J.; Argles, Tom W.; Harris, Nigel B. W.; Roberts, Nick M. W.

2015-07-01

Quantitative constraints on the rates of tectonic processes underpin our understanding of the mechanisms that form mountains. In the Sikkim Himalaya, late structural doming has revealed time-transgressive evidence of metamorphism and thrusting that permit calculation of the minimum rate of movement on a major ductile fault zone, the Main Central Thrust (MCT), by a novel methodology. U-Th-Pb monazite ages, compositions, and metamorphic pressure-temperature determinations from rocks directly beneath the MCT reveal that samples from 50 km along the transport direction of the thrust experienced similar prograde, peak, and retrograde metamorphic conditions at different times. In the southern, frontal edge of the thrust zone, the rocks were buried to conditions of 550°C and 0.8 GPa between 21 and 18 Ma along the prograde path. Peak metamorphic conditions of 650°C and 0.8-1.0 GPa were subsequently reached as this footwall material was underplated to the hanging wall at 17-14 Ma. This same process occurred at analogous metamorphic conditions between 18-16 Ma and 14.5-13 Ma in the midsection of the thrust zone and between 13 Ma and 12 Ma in the northern, rear edge of the thrust zone. Northward younging muscovite 40Ar/39Ar ages are consistently 4 Ma younger than the youngest monazite ages for equivalent samples. By combining the geochronological data with the >50 km minimum distance separating samples along the transport axis, a minimum average thrusting rate of 10 ± 3 mm yr-1 can be calculated. This provides a minimum constraint on the amount of Miocene India-Asia convergence that was accommodated along the MCT.

Thrusting and back-thrusting as post-emplacement kinematics of the Almora klippe: Insights from Low-temperature thermochronology

NASA Astrophysics Data System (ADS)

Patel, R. C.; Singh, Paramjeet; Lal, Nand

2015-06-01

Crystalline klippen over the Lesser Himalayan Sequence (LHS) in the Kumaon and Garhwal regions of NW-Himalaya, are the representative of southern portion of the Main Central Thrust (MCT) hanging wall. These were tectonically transported over the juxtaposed thrust sheets (Berinag, Tons and Ramgarh) of the LHS zone along the MCT. These klippen comprise of NW-SE trending synformal folded thrust sheet bounded by thrusts in the south and north. In the present study, the exhumation histories of two well-known klippen namely Almora and Baijnath, and the Ramgarh thrust sheet, in the Kumaon and Garhwal regions vis-a-vis Himalayan orogeny have been investigated using Apatite Fission Track (AFT) ages. Along a ~ 60 km long orogen perpendicular transect across the Almora klippe and the Ramgarh thrust sheet, 16 AFT cooling ages from the Almora klippe and 2 from the Ramgarh thrust sheet have been found to range from 3.7 ± 0.8 to 13.2 ± 2.7 Ma, and 6.3 ± 0.8 to 7.2 ± 1.0 Ma respectively. From LHS meta-sedimentary rocks only a single AFT age of 3.6 ± 0.8 Ma could be obtained. Three AFT ages from the Baijnath klippe range between 4.7 ± 0.5 and 6.6 ± 0.8 Ma. AFT ages and exhumation rates of different klippen show a dynamic coupling between tectonic and erosion processes in the Kumaon and Garhwal regions of NW-Himalaya. However, the tectonic processes play a dominant role in controlling the exhumation. Thrusting and back thrusting within the Almora klippe and Ramgarh thrust sheet are the post-emplacement kinematics that controlled the exhumation of the Almora klippe. Combining these results with the already published AFT ages from the crystalline klippen and the Higher Himalayan Crystalline (HHC), the kinematics of emplacement of the klippen over the LHS and exhumation pattern across the MCT in the Kumaon and Garhwal regions of NW-Himalaya have been investigated.

MEMS-Based Solid Propellant Rocket Array Thruster

NASA Astrophysics Data System (ADS)

Tanaka, Shuji; Hosokawa, Ryuichiro; Tokudome, Shin-Ichiro; Hori, Keiichi; Saito, Hirobumi; Watanabe, Masashi; Esashi, Masayoshi

The prototype of a solid propellant rocket array thruster for simple attitude control of a 10 kg class micro-spacecraft was completed and tested. The prototype has 10×10 φ0.8 mm solid propellant micro-rockets arrayed at a pitch of 1.2 mm on a 20×22 mm substrate. To realize such a dense array of micro-rockets, each ignition heater is powered from the backside of the thruster through an electrical feedthrough which passes along a propellant cylinder wall. Boron/potassium nitrate propellant (NAB) is used with/without lead rhodanide/potassium chlorate/nitrocellulose ignition aid (RK). Impulse thrust was measured by a pendulum method in air. Ignition required electric power of at least 3 4 W with RK and 4 6 W without RK. Measured impulse thrusts were from 2×10-5 Ns to 3×10-4 Ns after the calculation of compensation for air dumping.

Evidence for Seismic and Aseismic Slip along a Foreland Thrust Fault, Southern Appalachians

NASA Astrophysics Data System (ADS)

Newman, J.; Wells, R. K.; Holyoke, C. W.; Wojtal, S. F.

2013-12-01

Studies of deformation along ancient thrust faults form the basis for much of our fundamental understanding of fault and shear zone processes. These classic studies interpreted meso- and microstructures as formed during aseismic creep. Recent experimental studies, and studies of naturally deformed rocks in seismically active regions, reveal similar microstructures to those observed locally in a carbonate foreland thrust from the southern Appalachians, suggesting that this thrust fault preserves evidence of both seismic and aseismic deformation. The Copper Creek thrust, TN, accommodated 15-20 km displacement, at depths of 4-6 km, as estimated from balanced cross-sections. At the Diggs Gap exposure of the Copper Creek thrust, an approximately 2 cm thick, vein-like shear zone separates shale layers in the hanging wall and footwall. The shear zone is composed of anastomosing layers of ultrafine-grained calcite and/or shale as well as aggregate clasts of ultrafine-grained calcite or shale. The boundary between the shear zone and the hanging wall is sharp, with slickensides along the boundary, parallel to the shear zone movement direction. A 350 μm-thick layer of ultrafine-grained calcite separates the shear zone and the footwall. Fault parallel and perpendicular calcite veins are common in the footwall and increase in density towards the shear zone. Microstructures within the vein-like shear zone that are similar to those observed in experimental studies of unstable slip include: ultrafine-grained calcite (~0.34 μm), nano-aggregate clasts (100-300 nm), injection structures, and vein-wrapped and matrix-wrapped clasts. Not all structures within the shear zone and ultrafine-grained calcite layer suggest seismic slip. Within the footwall veins and calcite aggregate clasts within the shear zone, pores at twin-twin intersections suggest plasticity-induced fracturing as the main mechanism for grain size reduction. Interpenetrating grain boundaries in ultrafine-grained calcite and a lack of a lattice preferred orientation suggest ultrafine-grained calcite deformed by diffusion creep accommodated grain boundary sliding. These structures suggest a strain-rate between 10-15 - 10-11 s-1, using calcite flow laws at temperatures 150-250 °C. Microstructures suggest both seismic and aseismic slip along this ancient fault zone. During periods of aseismic slip, deformation is accommodated by plasticity-induced fracturing and diffusion creep. Calcite veins suggest an increase in pore-fluid pressure, contributing to fluidized and unstable flow, but also providing the calcite that deformed by diffusion creep during aseismic creep.

Structural analysis of Nalagarh lobe, NW Himalaya: implication of thrusting across tectonic edge of NW limb of Nahan salient, Himachal Pradesh, India

NASA Astrophysics Data System (ADS)

Bhakuni, S. S.; Philip, G.; Suresh, N.

2017-07-01

The Main Boundary Fault (MBF), convex towards southwest, forms the leading edge of the Nahan salient. Near the southern end of an oblique ramp, a lobe-shaped physiographic front, named in this work as Nalagarh lobe, has developed across NW limb of salient. The lobe has formed across the MBF that separates the hanging wall Lower Tertiary Dharmsala rocks from the footwall Upper Tertiary Siwalik rocks and overlying Quaternaries. In front of lobe, thrust fault splays (Splay-1 and Splay-2) and associated tectonic fabrics have developed within the Late Pleistocene fan deposit. Structural elements developed across the front of Nalagarh lobe are analysed with reference to evolution of lobe. An unweathered 15-m-high hanging wall or wedge top forms the uplifted and rejuvenated bedrock fault scarp of the MBF. Below the MBF, the fan deposit has underthrust along Splay-1. Later the Splay-2 formed within fan deposit near south of Splay-1. Geometry of the overturned limb of tight to isoclinal fault propagation fold, formed on Splay-2 plane, suggests that the fold formed by normal drag, produced by intermittent fault-slips along Splay-2. The displacement along Splay-2 offset the marker bed to 1 m by which some clasts rotated parallel to the traces of brittle axial planes of fold. The variable fold geometry and style of deformation are analysed along length of thrust splays for 5 km. It is revealed that the lobe is bounded by transverse thrust faults along its NW and SE margins. The geometry of salient and oblique ramp suggests that the transverse thrust faults and associated transverse folds formed by right-lateral displacement along the NW limb of the salient. Marking the northern margin of the intermontane piggyback basin of Pinjaur dun, the MBF is interpreted to be an out-of-sequence thrust that has brought up the Lower Tertiary Dharmsala rocks over the Late Pleistocene fan deposit. The geometry of lobe and its bounding transverse faults suggest that faults are intimately associated with the kinematics of the transition between the Nahan salient and Kangra recess. The transition is a transfer zone forming a long pre-Himalayan lineament across which the stratigraphic set of the Tethys and Lesser Himalaya is different. The study suggests that the lateral ramp on the Main Himalayan Thrust does not exist beneath the apex and also beneath the SE limb of the salient in the Sub-Himalayan region. This ramp should be present only beneath near end point of SW limb of the Nahan salient.

Tertiary structural evolution of the Gangdese thrust system southeastern Tibet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, An; Harrison, M.; Ryerson, F.J.

1994-09-10

Structural and thermochronological investigations of southern Tibet (Xizang) suggest that intracontinental thrusting has been the dominant cause for formation of thickened crust in the southernmost Tibetan plateau since late Oligocene. Two thrust systems are documented in this study: the north dipping Gangdese system (GTS) and the younger south dipping Renbu-Zedong system (RZT). West of Lhasa, the Gangdese thrust juxtaposes the Late Cretaceous forearc basin deposits of the Lhasa Block (the Xigaze Group) over the Tethyan sedimentary rocks of the Indian plate, whereas east of Lhasa, the fault juxtaposes the Late Cretaceous-Eocene, Andean-type arc (the Gangdese batholith) over Tethyan sedimentary rocks.more » Near Zedong, 150 km southeast of Lhasa, the Gangdese thrust is marked by a >200-m-thick mylonitic shear zone that consists of deformed granite and metasedimentary rocks. A major south dipping backthrust in the hanging wall of the Gangdese thrust puts the Xigaze Group over Tertiary conglomerates and the Gangdese plutonics north of Xigaze and west of Lhasa. A lower age bound for the Gangdese thrust of 18.3{+-}0.5 Ma is given by crosscutting relationships. The timing of slip on the Gangdese thrust is estimate to be 27-23 Ma from {sup 40}Ar/{sup 39}Ar thermochronology, and a displacement of at least 46{+-}9 km is indicated near Zedong. The age of the Gangdese thrust (GT) is consistent with an upper age limit of {approximately}24 Ma for the initiation of movement on the Main Central thrust. In places, the younger Renbu-Zedong fault is thrust over the trace of the GT, obscuring its exposure. The RZT appears to have been active at circa 18 Ma but had ceased movement by 8{+-}1 Ma. The suture between India and Asia has been complexely modified by development of the GTS, RZT, and, locally, strike-slip and normal fault systems. 64 refs., 14 figs., 2 tabs.« less

Structural inheritance and selective reactivation in the central Andes: Cenozoic deformation guided by pre-Andean structures in southern Peru

NASA Astrophysics Data System (ADS)

Perez, Nicholas D.; Horton, Brian K.; Carlotto, Victor

2016-03-01

Structural, stratigraphic, and geochronologic constraints from the Eastern Cordillera in the central Andean plateau of southern Peru (14-15°S) demonstrate the existence and position of major pre-Andean structures that controlled the accumulation of Triassic synrift fill and guided subsequent Cenozoic deformation. The timing of initial clastic deposition of the Triassic Mitu Group is here constrained to ~ 242-233 Ma on the basis of detrital and volcanic zircon U-Pb geochronology. Regionally distinct provenance variations, as provided by U-Pb age populations from localized synrift accumulations, demonstrate Triassic erosion of multiple diagnostic sources from diverse rift-flank uplifts. Stratigraphic correlations suggest synchronous initiation of extensional basins containing the Mitu Group, in contrast with previous interpretations of southward rift propagation. Triassic motion along the NE-dipping San Anton normal fault accommodated up to 7 km of throw and hanging-wall deposition of a synrift Mitu succession > 2.5 km thick. The contrasting orientation of a non-reactivated Triassic normal fault suggests selective inversion of individual structures in the Eastern Cordillera was dependent on fault dip and strike. Selective preservation of a ~ 4 km thick succession of Carboniferous-Permian strata in the down-dropped San Anton hanging wall, beneath the synrift Mitu Group, suggests large-scale erosional removal in the uplifted footwall. Field and map observations identify additional pre-Andean thrust faults and folds attributed to poorly understood Paleozoic orogenic events preserved in the San Anton hanging wall. Selective thrust reactivation of normal and reverse faults during later compression largely guided Cenozoic deformation in the Eastern Cordillera. The resulting structural compartmentalization and across-strike variations in kinematics and deformation style highlight the influence of inherited Paleozoic structures and Triassic normal faults on the long-term history of convergent margin deformation in the Andes.

Splay fault slip in a subduction margin, a new model of evolution

NASA Astrophysics Data System (ADS)

Conin, Marianne; Henry, Pierre; Godard, Vincent; Bourlange, Sylvain

2012-08-01

In subduction zones, major thrusts called splay faults are thought to slip coseismically during large earthquakes affecting the main plate interface. We propose an analytical condition for the activation of a splay fault based on force balance calculations and suggest thrusting along the splay fault is generally conditioned by the growth of the accretionary wedge, or by the erosion of the hanging wall. In theory, normal slip on the splay fault may occur when the décollement has a very low friction coefficient seaward. Such a low friction also implies an unstable extensional state within the outer wedge. Finite element elasto-plastic calculations with a geometry based on the Nankai Kumano section were performed and confirm that this analytical condition is a valid approximation. Furthermore, localized extension at a shallow level in the splay hanging wall is observed in models for a wide range of friction coefficients (from ∼0 to the value of internal friction coefficient of the rock, here equals to 0.4). The timing of slip established for the splay fault branch drilled on Nankai Kumano transect suggests a phase of concurrent splay and accretionary wedge growth ≈2 Ma to ≈1.5 Ma, followed by a locking of the splay ≈1.3 Ma. Active extension is observed in the hanging wall. This evolution can be explained by the activation of a deeper and weaker décollement, followed by an interruption of accretion. Activation of a splay as a normal fault, as hypothesized in the case of the Tohoku 2011 earthquake, can be achieved only if the friction coefficient on the décollement drops to near zero. We conclude that the tectonic stress state largely determines long-term variations of tightly related splay fault and outer décollement activity and thus influences where and how coseismic rupture ends, but that occurrence of normal slip on a splay fault requires coseismic friction reduction.

Fault-related fold styles and progressions in fold-thrust belts: Insights from sandbox modeling

NASA Astrophysics Data System (ADS)

Yan, Dan-Ping; Xu, Yan-Bo; Dong, Zhou-Bin; Qiu, Liang; Zhang, Sen; Wells, Michael

2016-03-01

Fault-related folds of variable structural styles and assemblages commonly coexist in orogenic belts with competent-incompetent interlayered sequences. Despite their commonality, the kinematic evolution of these structural styles and assemblages are often loosely constrained because multiple solutions exist in their structural progression during tectonic restoration. We use a sandbox modeling instrument with a particle image velocimetry monitor to test four designed sandbox models with multilayer competent-incompetent materials. Test results reveal that decollement folds initiate along selected incompetent layers with decreasing velocity difference and constant vorticity difference between the hanging wall and footwall of the initial fault tips. The decollement folds are progressively converted to fault-propagation folds and fault-bend folds through development of fault ramps breaking across competent layers and are followed by propagation into fault flats within an upper incompetent layer. Thick-skinned thrust is produced by initiating a decollement fault within the metamorphic basement. Progressive thrusting and uplifting of the thick-skinned thrust trigger initiation of the uppermost incompetent decollement with formation of a decollement fold and subsequent converting to fault-propagation and fault-bend folds, which combine together to form imbricate thrust. Breakouts at the base of the early formed fault ramps along the lowest incompetent layers, which may correspond to basement-cover contacts, domes the upmost decollement and imbricate thrusts to form passive roof duplexes and constitute the thin-skinned thrust belt. Structural styles and assemblages in each of tectonic stages are similar to that in the representative orogenic belts in the South China, Southern Appalachians, and Alpine orogenic belts.

Modeling the evolution of a ramp-flat-ramp thrust system: A geological application of DynEarthSol2D

NASA Astrophysics Data System (ADS)

Feng, L.; Choi, E.; Bartholomew, M. J.

2013-12-01

DynEarthSol2D (available at http://bitbucket.org/tan2/dynearthsol2) is a robust, adaptive, two-dimensional finite element code that solves the momentum balance and the heat equation in Lagrangian form using unstructured meshes. Verified in a number of benchmark problems, this solver uses contingent mesh adaptivity in places where shear strain is focused (localization) and a conservative mapping assisted by marker particles to preserve phase and facies boundaries during remeshing. We apply this cutting-edge geodynamic modeling tool to the evolution of a thrust fault with a ramp-flat-ramp geometry. The overall geometry of the fault is constrained by observations in the northern part of the southern Appalachian fold and thrust belt. Brittle crust is treated as a Mohr-Coulomb plastic material. The thrust fault is a zone of a finite thickness but has a lower cohesion and friction angle than its surrounding rocks. When an intervening flat separates two distinct sequential ramps crossing different stratigraphic intervals, the thrust system will experience more complex deformations than those from a single thrust fault ramp. The resultant deformations associated with sequential ramps would exhibit a spectrum of styles, of which two end members correspond to ';overprinting' and ';interference'. Reproducing these end-member styles as well as intermediate ones, our models show that the relative importance of overprinting versus interference is a sensitive function of initial fault geometry and hanging wall displacement. We further present stress and strain histories extracted from the models. If clearly distinguishable, they will guide the interpretation of field observations on thrust faults.

Width of the Surface Rupture Zone for Thrust Earthquakes and Implications for Earthquake Fault Zoning: Chi-Chi 1999 and Wenchuan 2008 Earthquakes

NASA Astrophysics Data System (ADS)

Boncio, P.; Caldarella, M.

2016-12-01

We analyze the zones of coseismic surface faulting along thrust faults, whit the aim of defining the most appropriate criteria for zoning the Surface Fault Rupture Hazard (SFRH) along thrust faults. Normal and strike-slip faults were deeply studied in the past, while thrust faults were not studied with comparable attention. We analyze the 1999 Chi-Chi, Taiwan (Mw 7.6) and 2008 Wenchuan, China (Mw 7.9) earthquakes. Several different types of coseismic fault scarps characterize the two earthquakes, depending on the topography, fault geometry and near-surface materials. For both the earthquakes, we collected from the literature, or measured in GIS-georeferenced published maps, data about the Width of the coseismic Rupture Zone (WRZ). The frequency distribution of WRZ compared to the trace of the main fault shows that the surface ruptures occur mainly on and near the main fault. Ruptures located away from the main fault occur mainly in the hanging wall. Where structural complexities are present (e.g., sharp bends, step-overs), WRZ is wider then for simple fault traces. We also fitted the distribution of the WRZ dataset with probability density functions, in order to define a criterion to remove outliers (e.g., by selecting 90% or 95% probability) and define the zone where the probability of SFRH is the highest. This might help in sizing the zones of SFRH during seismic microzonation (SM) mapping. In order to shape zones of SFRH, a very detailed earthquake geologic study of the fault is necessary. In the absence of such a very detailed study, during basic (First level) SM mapping, a width of 350-400 m seems to be recommended (95% of probability). If the fault is carefully mapped (higher level SM), one must consider that the highest SFRH is concentrated in a narrow zone, 50 m-wide, that should be considered as a "fault-avoidance (or setback) zone". These fault zones should be asymmetric. The ratio of footwall to hanging wall (FW:HW) calculated here ranges from 1:5 to 1:3.

Tertiary deformation history of southeastern and southwestern Tibet during the Indo-Asian collision

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, A.; Harrison, T.M.; Murphy, M.A.

1999-11-01

Geologic mapping and geochronological analysis in southwest (Kailas area) and southeast (Zedong area) Tibet reveal two major episodes of Tertiary crustal shortening along the classic Indus-Tsangpo suture in the Yalu River valley. The older event occurred between ca. 30 and 24 Ma during movement along the north-dipping Gangdese thrust. The development of this thrust caused extensive denudation of the Gangdese batholith in its hanging wall and underthrusting of the Xigase forearc strata in its footwall. Examination of timing of major tectonic events in central Asia suggests that the initiation of the Gangdese thrust was approximately coeval with the late Oligocenemore » initiation and development of north-south shortening in the eastern Kunlun Shan of northern Tibet, the Nan Shan at the northeastern end of the Altyn Tagh fault, the western Kunlun Shan at the southwestern end of the Altyn Tagh fault, and finally the Tian Shan (north of the tarim basin). Such regionally synchronous initiation of crustal shortening in and around the plateau may have been related to changes in convergence rate and direction between the Eurasian plate and the Indian and Pacific plates. The younger thrusting event along the Yalu River valley occurred between 19 and 10 Ma along the south-dipping Great Counter thrust system, equivalent to the locally named Renbu-Zedong thrust in southeastern Tibet, the Backthrust system in south-central Tibet, and the South Kailas thrust in southwest Tibet. The coeval development of the Great Counter thrust and the North Himalayan granite-gneiss dome belt is consistent with their development being related to thermal weakening of the north Himalayan and south Tibetan crust, due perhaps to thermal relaxation of an already thickened crust created by the early phase of collision between India and Asia or frictional heating along major thrusts, such as the Main Central thrust, beneath the Himalaya.« less

Solid Propellant Microthruster Design, Fabrication, and Testing for Nanosatellites

NASA Astrophysics Data System (ADS)

Sathiyanathan, Kartheephan

This thesis describes the design, fabrication, and testing of a solid propellant microthruster (SPM), which is a two-dimensional matrix of millimeter-sized rockets each capable of delivering millinewtons of thrust and millinewton-seconds of impulse to perform fine orbit and attitude corrections. The SPM is a potential payload for nanosatellites to increase spacecraft maneuverability and is constrained by strict mass, volume, and power requirements. The dimensions of the SPM in the millimeter-scale result in a number of scaling issues that need consideration such as a low Reynolds number, high heat loss, thermal and radical quenching, and incomplete combustion. The design of the SPM, engineered to address these issues, is outlined. The SPM fabrication using low-cost commercial off-the-shelf materials and standard micromachining is presented. The selection of a suitable propellant and its customization are described. Experimental results of SPM firing to demonstrate successful ignition and sustained combustion are presented for three configurations: nozzleless, sonic nozzle, and supersonic nozzle. The SPM is tested using a ballistic pendulum thrust stand. Impulse and thrust values are calculated and presented. The performance values of the SPM are found to be consistent with existing designs.

The X3: A 200 kW Class Nested Channel Hall Thruster

NASA Astrophysics Data System (ADS)

Sheehan, J. P.

2016-10-01

Electric propulsion has seen rapid adoption in recent years for commercial, scientific, and exploratory space missions. The X3 is a three channel nested channel Hall thruster, designed to push the boundaries of high power electric propulsion for cargo transfer to Mars and large military assets. It has been operated at thermal steady state up to 30 kW of power. Thrust measurements were made on an inverted pendulum thrust stand, indicating over 2000 s specific impulse and 65 mN/kW thrust to power ratio. Detailed plume measurements were made with Faraday and Langmuir probes. The multiple concentric channels provide better performance than the sum of the individual channel operations due to superior propellant utilization from its compact design. Using a high speed camera, the breathing and spoke mode instabilities were captured in all three channels. Spoke and breathing instabilities couple between the channels, indicating that complex plasma and neutral interactions are at play. Electron transport, both cross field and in the cathode plume, are well suited to be explored in a thruster of this size. Supported under NASA contract No. NNH16CP17C.

Laramide structure of the central Sangre de Cristo Mountains and adjacent Raton Basin, southern Colorado

USGS Publications Warehouse

Lindsey, D.A.

1998-01-01

Laramide structure of the central Sangre de Cristo Mountains (Culebra Range) is interpreted as a system of west-dipping, basement-involved thrusts and reverse faults. The Culebra thrust is the dominant structure in the central part of the range; it dips 30 -55?? west and brings Precambrian metamorphic base-ment rocks over unmetamorphosed Paleozoic rocks. East of the Culebra thrust, thrusts and reverse faults break the basement and overlying cover rocks into north-trending fault blocks; these boundary faults probably dip 40-60?? westward. The orientation of fault slickensides indicates oblique (northeast) slip on the Culebra thrust and dip-slip (ranging from eastward to northward) movement on adjacent faults. In sedimentary cover rocks, east-vergent anticlines overlie and merge with thrusts and reverse faults; these anticlines are interpreted as fault-propagation folds. Minor east-dipping thrusts and reverse faults (backthrusts) occur in both the hanging walls and footwalls of thrusts. The easternmost faults and folds of the Culebra Range form a continuous structural boundary between the Laramide Sangre de Cristo highland and the Raton Basin. Boundary structures consist of west-dipping frontal thrusts flanked on the basinward side by poorly exposed, east-dipping backthrusts. The backthrusts are interpreted to overlie structural wedges that have been emplaced above blind thrusts in the basin margin. West-dipping frontal thrusts and blind thrusts are interpreted to involve basement, but backthrusts are rooted in basin-margin cover rocks. At shallow structural levels where erosion has not exposed a frontal thrust, the structural boundary of the basin is represented by an anticline or monocline. Based on both regional and local stratigraphic evidence, Laramide deformation in the Culebra Range and accompanying synorogenic sedimentation in the western Raton Basin probably took place from latest Cretaceous through early Eocene time. The earliest evidence of uplift and erosion of a highland is the appearance of abundant feldspar in the Late Cretaceous Vermejo Formation. Above the Vermejo, unconformities overlain by conglomerate indicate continued thrusting and erosion of highlands from late Cretaceous (Raton) through Eocene (Cuchara) time. Eocene alluvial-fan conglomerates in the Cuchara Formation may represent erosion of the Culebra thrust block. Deposition in the Raton Basin probably shifted north from New Mexico to southern Colorado from Paleocene to Eocene time as movement on individual thrusts depressed adjacent segments of the basin.

Seismic interpretation and thrust tectonics of the Amadeus Basin, central Australia, along the BMR regional seismic line

NASA Astrophysics Data System (ADS)

Shaw, Russell D.; Korsch, Russell J.; Wright, C.; Goleby, B. R.

At the northern margin of the Amadeus Basin the monoclinal upturn (the MacDonnell Homocline) is interpreted to be the result of rotation and limited back-thrusting of the sedimentary sequence in front of a southerly-directed, imbricate basement thrust-wedge. This thrust complex is linked at depth to the crust-cutting Redbank Thrust Zone. In the northern part of the basin immediately to the south, regional seismic reflection profiling across the Missionary Plain shows a sub-horizontal, north-dipping, parautochthonous sedimentary sequence between about 8.5 km and 12.0 km thick. This sedimentary sequence shows upturning only at the northern and southern extremities, and represents an unusual, relatively undeformed region between converging thrust systems. In this intervening region, the crust appears to have been tilted downwards and northwards in response to the upthrusting to the north. Still farther to the south, the vertical uplift of the southern hanging wall of the Gardiner Thrust is about 6 km. Seismic reflection profiling in the region immediately south of the Gardiner Thrust indicates repetition of the sedimentary sequence. At the far end of the profile, in the Kernot Range, an imbricate thrust system fans ahead of a ramp-flat thrust pair. This thrust system (the Kernot Range Thrust System) occurs immediately north of an aeromagnetic domain boundary which marks the southern limit of a central ridge region characterized by thin Palaeozoic sedimentary cover and shallow depths to magnetic basement. A planar seismic event, imaged to a depth of at least 18 km, may correspond to the same boundary and is interpreted as a pre-basin Proterozoic thrust. Overall, the structure in the shallow sedimentary section in the central-southern region of the Amadeus Basin indicates that north-directed thrusting during the Dovonian-Carboniferous Alice Springs Orogeny was thin-skinned. During this orogeny an earlier thrust system, formed during the Petermann Ranges Orogeny and precursor orogenies in the Late Proterozoic, was reactivated with Proterozoic salt deposits localising the decollement zone. The Alice Springs Orogeny also reactivated a major mid Proterozoic province boundary in the basement to the north of the basin, resulting in major thrust movement at the northern basin margin.

Localized Flow of Frictional Or Creeping Materials In A Lower Flat Thrust To Ramp Transition

NASA Astrophysics Data System (ADS)

Maillot, B.; Leroy, Y.

The passage of rock through zones of localized shear deformation in the form of back- thrusts or kink planes is common in fold and thrust belts. The stationary flow through these two types of hinges is examined for the particular case of a lower flat to ramp transition of a fault-bend fold. The simple shear transformation resulting in strain lo- calization is studied both analytically and numerically. The overall equilibrium of the hanging wall, accounting for friction over the ramp, constrains the shear and normal forces acting on the hinge boundaries. For frictional materials, the localization oc- curs in the form of a velocity discontinuity, defining the backthrust, with a dip which is shown not to bissect ramp angle nor to conserve the thrust nappe thickness, if a criteria based on a minimization of the total dissipation is considered. For creeping materials, the strain localization as a kink plane is shown to require a destabilizing deformation mechanism, selected here to be flexural slip. The rotation of the stress tensor due to the gradient in pressure, the thicknening and thinning of the creeping material, the rate and amount of flexural slip through the hinge are analyzed to define potential tectonic markers.

Lateral propagation of folding and thrust faulting at Mahan, S.E. Iran

NASA Astrophysics Data System (ADS)

Walker, R. T.

2003-12-01

Folding identified near the town of Mahan in S.E. Iran has no record of historical activity, and yet there are clear geomorphological indications of recent fold growth, presumably driven by movements on underlying thrust faults. The structures at Mahan may still be capable of producing destructive earthquakes, posing a considerable hazard to local population centres. We describe a drainage evolution that shows the effect of lateral propagation of surface folding and the effect of tilting above an underlying thrust fault. River systems cross and incise through the fold segments. Each of these rivers show a distinct deflection parallel to the fold axis. This deflection starts several kilometres into the hanging-wall of the underlying thrust fault. Remnants of several abandoned drainage channels and abandoned alluvial fans are preserved within the folds. The westward lateral propagation of folding is also suggested by an increase in relief and exposure of deeper stratigraphic layers across fold segments in the east of the system, implying a greater cumulative displacement in the east than in the west. The preservation of numerous dry valleys across the fold suggests a continual forcing of drainage around the nose of the growing fold, rather than an along strike variation in slip-rate.

Morphologic evolution of the Central Andes of Peru

NASA Astrophysics Data System (ADS)

Gonzalez, Laura; Pfiffner, O. Adrian

2012-01-01

In this paper, we analyze the morphology of the Andes of Peru and its evolution based on the geometry of river channels, their bedrock profiles, stream gradient indices and the relation between thrust faults and morphology. The rivers of the Pacific Basin incised Mesozoic sediments of the Marañon thrust belt, Cenozoic volcanics and the granitic rocks of the Coastal Batholith. They are mainly bedrock channels with convex upward shapes and show signs of active ongoing incision. The changes in lithology do not correlate with breaks in slope of the channels (or knick points) such that the high gradient indices (K) with values between 2,000-3,000 and higher than 3,000 suggest that incision is controlled by tectonic activity. Our analysis reveals that many of the ranges of the Western Cordillera were uplifted to the actual elevations where peaks reach to 6,000 m above sea level by thrusting along steeply dipping faults. We correlate this uplift with the Quechua Phase of Neogene age documented for the Subandean thrust belt. The rivers of the Amazonas Basin have steep slopes and high gradient indices of 2,000-3,000 and locally more than 3,000 in those segments where the rivers flow over the crystalline basement of the Eastern Cordillera affected by vertical faulting. Gradient indices decrease to 1,000-2,000 within the east-vergent thrust belt of the Subandean Zone. Here a correlation between breaks in river channel slopes and location of thrust faults can be established, suggesting that the young, Quechua Phase thrust faults of the Subandean thrust belt, which involve Neogene sediments, influenced the channel geometry. In the eastern lowlands, these rivers become meandering and flow parallel to anticlines that formed in the hanging wall of Quechua Phase thrust faults, suggesting that the river courses were actively displaced outward into the foreland.

Stratigraphy and structure of the Sevier thrust belt and proximal foreland-basin system in central Utah: A transect from the Sevier Desert to the Wasatch Plateau

USGS Publications Warehouse

Lawton, T.F.; Sprinkel, D.A.; Decelles, P.G.; Mitra, G.; Sussman, A.J.; Weiss, M.P.

1997-01-01

The Sevier orogenic belt in central Utah comprises four north-northwest trending thrust plates and two structural culminations that record crustal shortening and uplift in late Mesozoic and early Tertiary time. Synorogenic clastic rocks, mostly conglomerate and sandstone, exposed within the thrust belt were deposited in wedge-top and foredeep depozones within the proximal part of the foreland-basin system. The geologic relations preserved between thrust structures and synorogenic deposits demonstrate a foreland-breaking sequence of thrust deformation that was modified by minor out-of-sequence thrust displacement. Structural culminations in the interior part of the thrust belt deformed and uplifted some of the thrust sheets following their emplacement. Strata in the foreland basin indicate that the thrust sheets of central Utah were emplaced between latest Jurassic and Eocene time. The oldest strata of the foredeep depozone (Cedar Mountain Formation) are Neocomian and were derived from the hanging wall of the Canyon Range thrust. The foredeep depozone subsided most rapidly during Albian through Santonian or early Campanian time and accumulated about 2.5 km of conglomeratic strata (Indianola Group). The overlying North Horn Formation accumulated in a wedge-top basin from the Campanian to the Eocene and records propagation of the Gunnison thrust beneath the former foredeep. The Canyon Range Conglomerate of the Canyon Mountains, equivalent to the Indianola Group and the North Horn Formation, was deposited exclusively in a wedge-top setting on the Canyon Range and Pavant thrust sheets. This field trip, a three day, west-to-east traverse of the Sevier orogenic belt in central Utah, visits localities where timing of thrust structures is demonstrated by geometry of cross-cutting relations, growth strata associated with faults and folds, or deformation of foredeep deposits. Stops in the Canyon Mountains emphasize geometry of late structural culminations and relationships of the Canyon Range thrust to growth strata deposited in the wedge-top depozone. Stops in the San Pitch Mountains illustrate deposits of the foredeep depozone and younger, superjacent wedge-top depozone. Stops in the Sanpete Valley and western part of the Wasatch Plateau examine the evolution of the foreland-basin system from foredeep to wedge-top during growth of a triangle zone near the front of the Gunnison thrust.

Deformation of Fold-and-Thrust Belts above a Viscous Detachment: New Insights from Analogue Modelling Experiments

NASA Astrophysics Data System (ADS)

Nogueira, Carlos R.; Marques, Fernando O.

2015-04-01

Theoretical and experimental studies on fold-and-thrusts belts (FTB) have shown that, under Coulomb conditions, deformation of brittle thrust wedges above a dry frictional basal contact is characterized by dominant frontward vergent thrusts (forethrusts) with thrust spacing and taper angle being directly influenced by the basal strength (increase in basal strength leading to narrower thrust spacing and higher taper angles); whereas thrust wedges deformed above a weak viscous detachment, such as salt, show a more symmetric thrust style (no prevailing vergence of thrusting) with wider thrust spacing and shallower wedges. However, different deformation patterns can be found on this last group of thrust wedges both in nature and experimentally. Therefore we focused on the strength (friction) of the wedge basal contact, the basal detachment. We used a parallelepiped box with four fixed walls and one mobile that worked as a vertical piston drove by a computer controlled stepping motor. Fine dry sand was used as the analogue of brittle rocks and silicone putty (PDMS) with Newtonian behaviour as analogue of the weak viscous detachment. To investigate the strength of basal contact on thrust wedge deformation, two configurations were used: 1) a horizontal sand pack with a dry frictional basal contact; and 2) a horizontal sand pack above a horizontal PDMS layer, acting as a basal weak viscous contact. Results of the experiments show that: the model with a dry frictional basal detachment support the predictions for the Coulomb wedges, showing a narrow wedge with dominant frontward vergence of thrusting, close spacing between FTs and high taper angle. The model with a weak viscous frictional basal detachment show that: 1) forethrusts (FT) are dominant showing clearly an imbricate asymmetric geometry, with wider spaced thrusts than the dry frictional basal model; 2) after FT initiation, the movement on the thrust can last up to 15% model shortening, leading to great amount of displacement along the FT; 3) intermittent reactivation of FTs also occurs despite the steepening of the FT plane and existence of new FT ahead, creating a high critical taper angle; 4) injection of PDMS from the basal weak layer into the FTs planes also favours to the long living of FTs and to the high critical taper angle; 5) vertical sand thickening in the hanging block also added to the taper angle.

New Structural Interpretation of the Central Confusion Range, Western Utah, Based On Balanced Cross Sections

NASA Astrophysics Data System (ADS)

Yezerski, D.; Greene, D. C.

2009-12-01

The Confusion Range is a topographically low mountain range in the Basin and Range of west-central Utah, located east of and in the hanging wall of the Snake Range core complex. Previous workers have used a gravity sliding model to interpret the Confusion Range as a large structural trough or synclinorium (e.g. Hose, 1977). Based on existing mapping (Hose, 1965; Hintze, 1974) and new field data, we use balanced and restored cross sections to reinterpret the structure of the Confusion Range as an east-vergent fold-and-thrust belt formed during the Sevier Orogeny. The Confusion Range consists of Cambro-Ordovician through Triassic strata, with predominantly thick-bedded, competent carbonate rocks in the lower Paleozoic (lPz) section and incompetent shales and thin-bedded carbonates in the upper Paleozoic (uPz) section. The contrasting mechanical behavior of these stratigraphic sections results in faulted folds within uPz carbonates above detachments in shale-rich units, deforming in response to ramp-flat thrust faulting of the underlying lPz units. East of the axis of the Conger Mountain (Mtn) syncline, we attribute the increase in structural elevation of lPz rocks to a subsurface thrust sheet consisting of lPz strata that advanced eastward via a high-angle ramp from a lower detachment in the Kanosh Shale to an upper detachment in the Pilot Shale. The doubling of lPz strata that resulted continues through the eastern Confusion Range where a series of small-displacement thrust faults comprising the Kings Canyon thrust system gently tilt strata to the west. In the Conger Range, west of the Conger Mtn syncline, our analysis focuses on reinterpreting the geometrically unlikely folding depicted in previous cross sections as more admissible, fault-cored, asymmetric, detached folding. In our interpretation, resistance created by a steeply-dipping thrust ramp in the lPz section west of Conger Mtn resulted in folding of uPz strata into an east-vergent anticline. Continued east-vergent contraction against the ramp resulted in the west-dipping limb of the anticline, consisting of Ely Limestone, developing into an overturned, west-vergent, synclinal backfold detached in the Chainman Shale. Further contraction exceeded the fold capacity of the detachment fold and resulted in the formation of the Browns Wash fault as an east-vergent thrust fault. The Browns Wash fault is a key component in the development of the present structural geometry, emplacing a west-vergent overturned syncline (detachment fold) in the hanging wall against an east-vergent overturned syncline (footwall syncline) in the footwall. Further west, underlying the western Conger Range and Buckskin Hills, lPz strata are exposed in what we interpret to be a ramp anticline overlying a subsurface thrust ramp. This interpretation implies a lateral ramp separating lPz rocks in the Buckskin Hills from uPz rocks exposed in the Knoll Hill anticline to the north. UPz and Mesozoic strata exposed to the west on the edge of Snake Valley were emplaced by a Tertiary west-dipping normal fault that truncated the west limb of the ramp anticline.

Folding of a detachment and fault - Modified detachment folding along a lateral ramp, southwestern Montana, USA

NASA Astrophysics Data System (ADS)

Schmidt, Christopher; Whisner, S. Christopher; Whisner, Jennifer B.

2014-12-01

The inversion of the Middle Proterozoic Belt sedimentary basin during Late Cretaceous thrusting in Montana produced a large eastwardly-convex salient, the southern boundary of which is a 200 km-long oblique to lateral ramp subtended by a detachment between the Belt rocks and Archean basement. A 10 km-long lateral ramp segment exposes the upper levels of the detachment where hanging wall Belt rocks have moved out over the Paleozoic and Mesozoic section. The hanging wall structure consists of a train of high amplitude, faulted, asymmetrical detachment folds. Initial west-east shortening produced layer parallel shortening fabrics and dominantly strike slip faulting followed by symmetrical detachment folding. 'Lock-up' of movement on the detachment surface produced regional simple shear and caused the detachment folds to become asymmetrical and faulted. Folding of the detachment surface after lock-up modified the easternmost detachment folds further into a southeast-verging, overturned fold pair with a ramp-related fault along the base of the stretched mutual limb.

Slosh dynamics of a spin-stabilized spacecraft comprising off-axis tanks filled partially with liquid propellant

NASA Technical Reports Server (NTRS)

Fontenot, L. L.

1981-01-01

The fundamental nonlinear equations of motion were derived and the specialized to a steady-state rotation of the vehicle about a given axis of rotation. A thrust about the spin axis was introduced. A perturbation solution was derived which linearizes the problem. The effect of the centrifugal and coriolis accelerations together with vorticity are implicitly taken into consideration in the formulation. A variational formulation of the associated boundary conditions is presented. For practical cases it is shown that the simple classical pendulum representation for slosh is not very appealing for a spinning spacecraft unless severe restrictions are allowed.

Contrasted terrace systems of the lower Moulouya valley as indicator of crustal deformation in NE Morocco

NASA Astrophysics Data System (ADS)

Rixhon, Gilles; Bartz, Melanie; El Ouahabi, Meriam; Szemkus, Nina; Brueckner, Helmut

2016-04-01

The Moulouya river has the largest catchment in Morocco and drains an area which is characterized by active crustal deformation during the Late Cenozoic due to the convergence between the African and Eurasian plates. As yet, its Pleistocene terrace sequence remains poorly documented. Our study focuses on the lowermost reach of the river in NE Morocco, which drains the Triffa sedimentary basin directly upstream of the estuary. New field observations, measurements and sedimentological data reveal contrasted fluvial environments on either side of a newly identified thrust zone, which disrupts the whole sedimentary basin and is associated with N-S compressive shortening in this region (Barcos et al., 2014). Long-lasting fluvial aggradation, materialized by ≥37 m-thick stacked fill terraces, and the development of a well-preserved terrace staircase, with (at least) three Pleistocene terrace levels, occur in the footwall and the hanging wall of the thrust, respectively. Same as for the Pleistocene terrace sediments of the middle Moulouya, a recurrent sedimentary pattern, characterized by fining-upward sequences was observed in the studied terrace profiles. Assessing the rates of crustal deformation along this main thrust zone requires age estimations for these Pleistocene terrace deposits of the lower Moulouya on each side of the thrust. Samples for luminescence (OSL/IRSL), electron spin resonance (ESR, on quartz) and cosmogenic nuclide dating (26Al/10Be, burial dating) were collected in terrace deposits located both in the foot- and hanging walls. Sample preparation and analysis as well as age determination are in progress. The preliminary data mentioned above, soon to be completed by chronological data, agree well with morphometric indicators stating that the whole Moulouya catchment is at disequilibrium state (Barcos et al., 2014). This is confirmed by several knickpoints in its longitudinal profile. Late Cenozoic uplift associated with crustal shortening, which occurred in the lowermost reach of the river, may have both hindered profile rectification of the Moulouya and, at the same time, buffered the effects of long-term base-level changes due to eustatic sea-level variations. Reference: Barcos, L., Jabaloy, A., Azdimousa, A., Asebriy, L., Gómez-Ortiz, D., Rodríguez-Peces, M.J., Tejero, R., Pérez-Peña, J.V., 2014. Study of relief changes related to active doming in the eastern Moroccan Rif (Morocco) using geomorphological indices. J. African Earth Sci. 100, 493-509.

Implications of meso- to micro-scale deformation for fault sealing capacity: Insights from the Lenghu5 fold-and-thrust belt, Qaidam Basin, NE Tibetan Plateau

NASA Astrophysics Data System (ADS)

Xie, Liujuan; Pei, Yangwen; Li, Anren; Wu, Kongyou

2018-06-01

As faults can be barriers to or conduits for fluid flow, it is critical to understand fault seal processes and their effects on the sealing capacity of a fault zone. Apart from the stratigraphic juxtaposition between the hanging wall and footwall, the development of fault rocks is of great importance in changing the sealing capacity of a fault zone. Therefore, field-based structural analysis has been employed to identify the meso-scale and micro-scale deformation features and to understand their effects on modifying the porosity of fault rocks. In this study, the Lenghu5 fold-and-thrust belt (northern Qaidam Basin, NE Tibetan Plateau), with well-exposed outcrops, was selected as an example for meso-scale outcrop mapping and SEM (Scanning Electron Microscope) micro-scale structural analysis. The detailed outcrop maps enabled us to link the samples with meso-scale fault architecture. The representative rock samples, collected in both the fault zones and the undeformed hanging walls/footwalls, were studied by SEM micro-structural analysis to identify the deformation features at the micro-scale and evaluate their influences on the fluid flow properties of the fault rocks. Based on the multi-scale structural analyses, the deformation mechanisms accounting for porosity reduction in the fault rocks have been identified, which are clay smearing, phyllosilicate-framework networking and cataclasis. The sealing capacity is highly dependent on the clay content: high concentrations of clay minerals in fault rocks are likely to form continuous clay smears or micro- clay smears between framework silicates, which can significantly decrease the porosity of the fault rocks. However, there is no direct link between the fault rocks and host rocks. Similar stratigraphic juxtapositions can generate fault rocks with very different magnitudes of porosity reduction. The resultant fault rocks can only be predicted only when the fault throw is smaller than the thickness of a faulted bed, in which scenario self-juxtaposition forms between the hanging wall and footwall.

Complex rupture mechanism and topography control symmetry of mass-wasting pattern, 2010 Haiti earthquake

NASA Astrophysics Data System (ADS)

Gorum, Tolga; van Westen, Cees J.; Korup, Oliver; van der Meijde, Mark; Fan, Xuanmei; van der Meer, Freek D.

2013-02-01

The 12 January 2010 Mw 7.0 Haiti earthquake occurred in a complex deformation zone at the boundary between the North American and Caribbean plates. Combined geodetic, geological and seismological data posited that surface deformation was driven by rupture on the Léogâne blind thrust fault, while part of the rupture occurred as deep lateral slip on the Enriquillo-Plantain Garden Fault (EPGF). The earthquake triggered > 4490 landslides, mainly shallow, disrupted rock falls, debris-soil falls and slides, and a few lateral spreads, over an area of ~ 2150 km2. The regional distribution of these slope failures defies those of most similar earthquake-triggered landslide episodes reported previously. Most of the coseismic landslides did not proliferate in the hanging wall of the main rupture, but clustered instead at the junction of the blind Léogâne and EPGF ruptures, where topographic relief and hillslope steepness are above average. Also, low-relief areas subjected to high coseismic uplift were prone to lesser hanging wall slope instability than previous studies would suggest. We argue that a combined effect of complex rupture dynamics and topography primarily control this previously rarely documented landslide pattern. Compared to recent thrust fault-earthquakes of similar magnitudes elsewhere, we conclude that lower static stress drop, mean fault displacement, and blind ruptures of the 2010 Haiti earthquake resulted in fewer, smaller, and more symmetrically distributed landslides than previous studies would suggest. Our findings caution against overly relying on across-the-board models of slope stability response to seismic ground shaking.

Earthquake swarm of Himachal Pradesh in northwest Himalaya and its seismotectonic implications

NASA Astrophysics Data System (ADS)

Singh, Rakesh; Prasath, R. Arun; Paul, Ajay; Kumar, Naresh

2018-02-01

On the 27th of August 2016, a seismic swarm activity consisting of 58 earthquakes (1.5 ≤ ML ≤ 4.4), which occurred in Rampur area of the Kullu-Rampur Tectonic window of Himachal Pradesh in Northwest Himalaya. The epicenters of these events are located at the northern front of the Berinag Thrust in its hanging wall. To better understand the seismotectonics of this region, we analyzed the spectral source parameters and source mechanism of this swam activity. Spectral analysis shows the low stress drop values (from 0.05 to 28.9 bars), suggesting that the upper crust has low strength to withstand accumulated strain energy in this region. The Moment Tensor solutions of 12 earthquakes (≥2.7ML) obtained by waveform inversion yield the shallow centroid depths between 5 and 10 km. All these events are of dominantly thrust fault mechanism having an average dip angle of ∼30°. The P-axes and the maximum horizontal compressive stresses are NE-SW oriented; the relative motion of the Indian Plate. The present study reveals that the swarm activity in the Himachal region of NW Himalaya is related to the out-of-sequence thrusting or the Lesser Himalayan Duplex system.

Geophysical Evidence for the Tectonic Evolution of the Inverted Belt-Purcell Basin, Northwestern Montana

NASA Astrophysics Data System (ADS)

Rutherford, B. S.; Speece, M. A.; Constenius, K. N.

2015-12-01

The geometry of the Precambrian Belt-Purcell basin and subsequent allochthon, that dominates the geology of northwestern Montana, played a critical role in the development of compressional structures during orogenesis and their ensuing reactivation during the later phase of extensional collapse. Five reprocessed seismic reflection profiles provide images in the Swan Range and adjacent valleys that we have correlated to published seismic data north into Canada. Reflections from syndepositional sills encased within Lower Belt rocks offer clues to the configuration of the basin prior to its tectonic inversion. Thick basinal facies of the Lewis salient are contrasted by thin shelfal facies found in hanging wall rocks of frontal Belt carrying thrusts south of the salient. The along strike change in hanging wall rocks reflects the original configuration of the Belt basin margin. Rocks of the Lewis salient were deposited in an embayment on the northeastern margin of the Belt basin. Shelfal accumlations of the embayment comprise an autochthonous wedge that has remained in the footwall of the Lewis thrust system. South of the embayment and related salient, nearly the entire Belt basin was detached from pre-Belt crystalline rocks and inverted at the latitude of the Sawtooth Range. Deeply exhumed Phanerozoic rocks of the Sawtooth Range are a direct consequence of the thin wedge geometry of the detached basin south of the Lewis salient that required growth of a substantial orogenic wedge to obtain critical taper values. We offer an alternate interpretation of a >10 km high, west facing décollement ramp that coincides with the Belt-Purcell basin margin. Previous interpretations in Montana have inferred the location of the basin margin ramp to approximate the trace of the Purcell Anticlinorium. Seismic data and cross-section balancing suggest the Rocky Mountain Trench as a more accurate location. Based on our proposed position of the basin margin the Belt-Purcell allocthon requires insignificant rotation during thrust emplacement which is in agreement with published interpretations of paleomagnetic data. We suggest small (<5°) clockwise rotation is due to an increase in extensional slip from the international border south to the Flathead Valley as opposed to an increase in compressional shortening to the north.The geometry of the Precambrian Belt-Purcell basin and subsequent allochthon, that dominates the geology of northwestern Montana, played a critical role in the development of compressional structures during orogenesis and their ensuing reactivation during the later phase of extensional collapse. Five reprocessed seismic reflection profiles provide images in the Swan Range and adjacent valleys that we have correlated to published seismic data north into Canada. Reflections from syndepositional sills encased within Lower Belt rocks offer clues to the configuration of the basin prior to its tectonic inversion. Thick basinal facies of the Lewis salient are contrasted by thin shelfal facies found in hanging wall rocks of frontal Belt carrying thrusts south of the salient. The along strike change in hanging wall rocks reflects the original configuration of the Belt basin margin. Rocks of the Lewis salient were deposited in an embayment on the northeastern margin of the Belt basin. Shelfal accumlations of the embayment comprise an autochthonous wedge that has remained in the footwall of the Lewis thrust system. South of the embayment and related salient, nearly the entire Belt basin was detached from pre-Belt crystalline rocks and inverted at the latitude of the Sawtooth Range. Deeply exhumed Phanerozoic rocks of the Sawtooth Range are a direct consequence of the thin wedge geometry of the detached basin south of the Lewis salient that required growth of a substantial orogenic wedge to obtain critical taper values. We offer an alternate interpretation of a >10 km high, west facing décollement ramp that coincides with the Belt-Purcell basin margin. Previous interpretations in Montana have inferred the location of the basin margin ramp to approximate the trace of the Purcell Anticlinorium. Seismic data and cross-section balancing suggest the Rocky Mountain Trench as a more accurate location. Based on our proposed position of the basin margin the Belt-Purcell allocthon requires insignificant rotation during thrust emplacement which is in agreement with published interpretations of paleomagnetic data. We suggest small (<5°) clockwise rotation is due to an increase in extensional slip from the international border south to the Flathead Valley as opposed to an increase in compressional shortening to the north.

Initial Thrust Measurements of Marshall's Ion-ioN Thruster

NASA Technical Reports Server (NTRS)

Caruso, Natalie R. S.; Scogin, Tyler; Liu, Thomas M.; Walker, Mitchell L. R.; Polzin, Kurt A.; Dankanich, John W.

2015-01-01

Electronegative ion thrusters are a variation of traditional gridded ion thruster technology differentiated by the production and acceleration of both positive and negative ions. Benefits of electronegative ion thrusters include the elimination of lifetime-limiting cathodes from the thruster architecture and the ability to generate appreciable thrust from both charge species. While much progress has been made in the development of electronegative ion thruster technology, direct thrust measurements are required to unambiguously demonstrate the efficacy of the concept and support continued development. In the present work, direct thrust measurements of the thrust produced by the MINT (Marshall's Ion-ioN Thruster) are performed using an inverted-pendulum thrust stand in the High-Power Electric Propulsion Laboratory's Vacuum Test Facility-1 at the Georgia Institute of Technology with operating pressures ranging from 4.8 x 10(exp -5) and 5.7 x 10(exp -5) torr. Thrust is recorded while operating with a propellant volumetric mixture ratio of 5:1 argon to nitrogen with total volumetric flow rates of 6, 12, and 24 sccm (0.17, 0.34, and 0.68 mg/s). Plasma is generated using a helical antenna at 13.56 MHz and radio frequency (RF) power levels of 150 and 350 W. The acceleration grid assembly is operated using both sinusoidal and square waveform biases of +/-350 V at frequencies of 4, 10, 25, 125, and 225 kHz. Thrust is recorded for two separate thruster configurations: with and without the magnetic filter. No thrust is discernable during thruster operation without the magnetic filter for any volumetric flow rate, RF forward Power level, or acceleration grid biasing scheme. For the full thruster configuration, with the magnetic filter installed, a brief burst of thrust of approximately 3.75 mN +/- 3 mN of error is observed at the start of grid operation for a volumetric flow rate of 24 sccm at 350 W RF power using a sinusoidal waveform grid bias at 125 kHz and +/- 350 V. Similar bursts in thrust are observed using a square waveform grid bias at 10 kHz and +/- 350 V for volumetric flow rates of 6, 10, and 12 sccm at 150, 350, and 350 W respectively. The only operating condition that exhibits repeated thrust spikes throughout thruster operation is the 24 sccm condition with a 5:1 mixture ratio at 150 W RF power using the 10 kHz square waveform acceleration grid bias. Thrust spikes for this condition measure 3 mN with an error of +/- 2.5 mN. There are no operating conditions tested that show continuous thrust production.

Geomorphic indices indicated differential active tectonics of the Longmen Shan

NASA Astrophysics Data System (ADS)

Gao, M.; Xu, X.; Tan, X.

2012-12-01

The Longmen Shan thrust belt is located at the eastern margin of the Tibetan Plateau. It is a region of rapid active tectonics with high erosion rates and dense vegetation. The structure of the Longmen Shan region is dominated by northeast-trending thrusts and overturned folds that verge to the east and southeast (Burchfiel et al. 1995, Chen and Wilson 1996). The Longmen Shan thrust belt consists of three major faults from west to east: back-range fault, central fault, and frontal-range fault. The Mw 7.9 Wenchuan earthquake ruptured two large thrust faults along the Longmen Shan thrust belt (Xiwei et al., 2009). In this paper, we focus on investigating the spatial variance of tectonic activeness from the back-range fault to the frontal-range fault, particular emphasis on the differential recent tectonic activeness reflected by the hypsometry and the asymmetric factor of the drainage. Results from asymmetric factor indicate the back-rannge thrust fault on the south of the Maoxian caused drainage basins tilted on the hanging wall. For the north of the Maoxian, the strike-slip fault controlled the shapes of the drainage basins. Constantly river capture caused the expansion of the drainage basins which traversed by the fault. The drainages on the central fault and the frontal-range fault are also controlled by the fault slip. The drainage asymmetric factor suggested the central and southern segments of the Longmen Shan are more active than the northern segment, which is coherence with results of Huiping et al. (2010). The results from hypsometry show the back-range fault is the most active fault among the three major faults. Central fault is less active than the back-range fault but more active than the frontal-range fault. Beichuan is identified as the most active area along the central fault. Our geomorphic indices reflect an overall eastward decreasing of tectonic activeness of the Longmen Shan thrust belt.

The anatomy of a major late-stage thrust and implications for models of late-stage collisional orogenesis in the Caledonian crust of northern Scandinavia

NASA Astrophysics Data System (ADS)

Anderson, Mark; Hames, Willis; Stokes, Alison

2010-05-01

Within the stack of Caledonian crystalline thrust sheets of northern Scandinavia, a single amphibolite facies lithotectonic unit, the Småtinden nappe, is identified as a major, basement-coupled ("stretching") shear zone. This dominantly pelitic unit achieved peak metamorphic conditions of 535-550°C and 8-9kbars, and the stretching geometry suggests that this most likely occurred in response to overthrusting of a hot, pre-assembled Caledonian thrust stack. Along-strike variations in microstructural geometries and patterns of mineral zoning in widely developed porphyroblast phases suggest, however, subsequent strain partitioning within the zone during late-stage decoupling of the thrust stack from the basement along major out-of-sequence thrusts. Large parts of the nappe are characterised by relatively late, static growth preserving concordant Si-Se relationships, and typically symmetrical external fabrics consistent with formation under dominantly pure shear conditions. In the Salangen area, however, the nappe is characterised by early garnet growth, with discordant Si-Se relationships and asymmetric external fabric geometries consistent with formation during ESE-directed simple shear. Remarkably consistent thermometric estimates from chlorites in both regimes (post- and syn-shearing) suggest that out-of-sequence ramping occurred at temperatures in the range 370-400 ̊C, within the typical range of blocking temperatures for argon retention in muscovite. 40Ar-39Ar dating of muscovites from S-C fabrics in the out-of-sequence shear zone suggest that late-stage thrusting occurred during the middle-late Devonian (ca. 395-375 Ma). Hanging-wall and footwall geometries coupled with these radiometric dates indicate that the development of these late thrusts closely relates to reactivation of pre-Caledonian Baltic basement during the Devonian (400-370 Ma). East-west contraction during the upper end of this time frame is peculiar considering that this was the period of large magnitude and rapid extension in western Norway.

Geometry of a large-scale low-angle mid-crustal thrust (Woodroffe Thrust, Central Australia)

NASA Astrophysics Data System (ADS)

Wex, Sebastian; Mancktelow, Neil S.; Hawemann, Friedrich; Pennacchioni, Giorgio; Camacho, Alfredo

2015-04-01

Young orogens, such as the Alps, mainly expose the upper part of the continental crust and it is not possible to follow large-scale thrusts (e.g. the Glarus Thrust) to great depth in order to study their changing rheological behavior. This knowledge, however, is crucial for determining the overall kinematic and dynamic response during collision, as middle to lower crustal rocks represent the major part of the total crustal section. Information from deeper parts of the continental crust can only be obtained directly by investigating regions where these levels are now exhumed. The Musgrave Ranges in Central Australia is a very well exposed, semi-desert area, in which numerous large-scale shear zones developed during the Petermann Orogeny around 550 Ma. The most prominent structure is the ˜400 km long E-W trending Woodroffe Thrust, which placed ˜1.2 Ga granulites onto similarly-aged amphibolite and granulite facies gneisses along a generally south-dipping thrust plane with a top-to-north shear sense. Geothermobarometric calculations on the associated mylonites established that the structure developed under mid-crustal conditions (500-650°C, 0.8-1 GPa). Regional P/T variations in the direction of thrusting are small, but show trends consistent with the south-dipping orientation of the thrust plane, which predicts deeper levels and a higher metamorphic grade in the south than in the north. They imply a very low gradient of only around 3°C/km for a distance of some 30 km in the movement direction of the thrust. Combined with a geothermal gradient on the order of 20°C/km, calculated from four separate P/T estimates from the hanging wall and footwall, this regional gradient indicates that the Woodroffe Thrust was originally shallow-dipping at an average angle of only around 9°. This suggests that upper crustal brittle thrusts do not necessarily steepen into the middle to lower crust, but can define very shallow-dipping, large-scale planar features, with dimensions in the order of hundreds of kilometres. Such a geometry would require the rocks to be weak, but field observations (e.g. large volumes of syn-tectonic pseudotachylyte) argue for strong behaviour, involving alternating fast (seismic) fracturing and slow (aseismic) creep.

A Change of Inertia-Supporting the Thrust Vector Control of the Space Launch System

NASA Technical Reports Server (NTRS)

Dziubanek, Adam J.

2012-01-01

The Space Launch System (SLS) is America's next launch vehicle. To utilize the vehicle more economically, heritage hardware from the Space Transportation System (STS) will be used when possible. The Solid Rocket Booster (SRB) actuators could possibly be used in the core stage of the SLS. The dynamic characteristics of the SRB actuator will need to be tested on an Inertia Load Stand (ILS) that has been converted to Space Shuttle Main Engine (SSME). The inertia on the pendulum of the ILS will need to be changed to match the SSME inertia. In this testing environment an SRB actuator can be tested with the equivalent resistence of an SSME.

Kinematics of syn- and post-exhumational shear zones at Lago di Cignana (Western Alps, Italy): constraints on the exhumation of Zermatt-Saas (ultra)high-pressure rocks and deformation along the Combin Fault and Dent Blanche Basal Thrust

NASA Astrophysics Data System (ADS)

Kirst, Frederik; Leiss, Bernd

2017-01-01

Kinematic analyses of shear zones at Lago di Cignana in the Italian Western Alps were used to constrain the structural evolution of units from the Piemont-Ligurian oceanic realm (Zermatt-Saas and Combin zones) and the Adriatic continental margin (Dent Blanche nappe) during Palaeogene syn- and post-exhumational deformation. Exhumation of Zermatt-Saas (U)HP rocks to approximately lower crustal levels at ca. 39 Ma occurred during normal-sense top-(S)E shearing under epidote-amphibolite-facies conditions. Juxtaposition with the overlying Combin zone along the Combin Fault at mid-crustal levels occurred during greenschist-facies normal-sense top-SE shearing at ca. 38 Ma. The scarcity of top-SE kinematic indicators in the hanging wall of the Combin Fault probably resulted from strain localization along the uppermost Zermatt-Saas zone and obliteration by subsequent deformation. A phase of dominant pure shear deformation around 35 Ma affected units in the direct footwall and hanging wall of the Combin Fault. It is interpreted to reflect NW-SE crustal elongation during updoming of the nappe stack as a result of underthrusting of European continental margin units and the onset of continental collision. This phase was partly accompanied and followed by ductile bulk top-NW shearing, especially at higher structural levels, which transitioned into semi-ductile to brittle normal-sense top-NW deformation due to Vanzone phase folding from ca. 32 Ma onwards. Our structural observations suggest that syn-exhumational deformation is partly preserved within units and shear zones exposed at Lago di Cignana but also that the Combin Fault and Dent Blanche Basal Thrust experienced significant post-exhumational deformation reworking and overprinting earlier structures.

Soro West: A non-seismically defined, fault cut-off prospect in the Papuan Fold and Thrust Belt, Papua New Guinea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, W.F.; Swift, C.M. Jr.

Soro West is a fault cut-off prospect located in the frontal portion of the Papuan Fold and Thrust Belt. Prospective Toro and Imburu sandstones are interpreted to be in the hanging wall of the Soro Thrust. Truncation against the thrust, both updip and through lateral ramps, provides the trapping mechanism. The Soro West Prospect was defined using geological, geochemical, remote sensing, and geophysical data. The definition and location of the trap is a primary risk and work was focused on this aspect. Surface geological data (lithology, strikes, and dips) topography and synthetic aperture radar imagery were incorporated into the evaluation.more » Statistical curvature analysis techniques helped define the shape of the structure and the locations of the lateral ramps. Strontium isotope analyses of Darai Limestone surface samples refined erosional levels using a locally-derived reference curve. Severe karst precludes the acquisition of coherent surface seismic data, so the primary geophysical tool used was magnetotellurics (MT). A detailed, pre-survey feasibility study defined expected responses from alternative structural models. The MT data demonstrated that the limestone at surface is underlain by thick conductive clastics and not another Darai Limestone sheet. The data also constrained the range of fault cut-off positions significantly. Multiple, three-dimensionally consistent, restorable alternative structural models were created using results from all analyses. These led to a positive assessment of the prospect and an exploratory test is to be drilled in 1996.« less

Evidence for large-scale imbrication during Eocene syn-orogenic exhumation of the Hellenic subduction channel (Cyclades, Greece)

NASA Astrophysics Data System (ADS)

Grasemann, Bernhard; Huet, Benjamin; Schneider, David; Rice, Hugh; Lemonnier, Nicolas; Tschegg, Cornelius

2017-04-01

In the Cyclades, Miocene post-orogenic back-arc extension overprinted the exhumed syn- orogenic Eocene subduction channel. Whereas the exact geometry and kinematics of the syn-orogenic exhumation are still controversial, but must have involved a floor thrust and an apparent normal fault at the roof, the post-orogenic extension, leading to the exhumation of Cordilleran-type metamorphic core complexes, is well constrained by several major detachment systems. On the island of Milos, which is part of the South Aegean Volcanic Arc, minor outcrops of schist occur. New data indicate that these witnessed Eocene blueschist facies metamorphism at 8.5 kbar and 400°C, but escaped the Miocene extensional overprint, as they lie in the hanging wall of the West Cycladic Detachment System. In contrast, eclogite pebbles in "Green Lahars" on Milos yield metamorphic conditions of 19.5 kbar at 550°C. Both high-pressure units belong to the Cycladic Blueschist Unit and can only have been juxtaposed by thrusting. This indicates that two nappes, the newly defined Cycladic Blueschist Nappe and the overlying Cycladic Eclogite Nappe, both comprising rocks of the Cycladic Blueschist Unit, exist on Milos. These nappes probably also form the other Cycladic islands, separated by a syn-orogenic thrust, which we name the Trans Cycladic Thrust. The Trans Cycladic Thrust, which traces the orientation of the syn-orogenic exhumation channel, is partly offset by the post-orogenic Miocene extensional detachment systems. As a result of the Mid- to Late Miocene clockwise crustal block rotation, the syn-orogenic channel, and hence the Trans Cycladic Thrust, bends through 90° at Milos, changing from a W-E trending to a N-S trending extrusion-related stretching lineation. Restoration of the Miocene block-rotation and extension results in syn-orogenic thrusting kinematics (top-SSW) in the Cycladic Blueschist Nappe and along the Trans Cycladic Thrust and syn-orogenic apparent normal faulting kinematics (top-NNE) at the roof of the Cycladic Eclogite Nappe, consistent with the Eocene extrusion of the high-pressure rocks in the Cyclades.

Large-scale fault interactions at the termination of a subduction margin

NASA Astrophysics Data System (ADS)

Mouslopoulou, V.; Nicol, A., , Prof; Moreno, M.; Oncken, O.; Begg, J.; Kufner, S. K.

2017-12-01

Active subduction margins terminate against, and transfer their slip onto, plate-boundary transform faults. The manner in which plate motion is accommodated and partitioned across such kinematic transitions from thrust to strike-slip faulting over earthquake timescales, is poorly documented. The 2016 November 14th, Mw 7.8 Kaikoura Earthquake provides a rare snapshot of how seismic-slip may be accommodated at the tip of an active subduction margin. Analysis of uplift data collected using a range of techniques (field measurements, GPS, LiDAR) and published mapping coupled with 3D dislocation modelling indicates that earthquake-slip ruptured multiple faults with various orientations and slip mechanisms. Modelled and measured uplift patterns indicate that slip on the plate-interface was minor. Instead, a large offshore thrust fault, modelled to splay-off the plate-interface and to extend to the seafloor up to 15 km east of the South Island, appears to have released subduction-related strain and to have facilitated slip on numerous, strike-slip and oblique-slip faults on its hanging-wall. The Kaikoura earthquake suggests that these large splay-thrust faults provide a key mechanism in the transfer of plate motion at the termination of a subduction margin and represent an important seismic hazard.

Fold-to-fault progression of a major thrust zone revealed in horses of the North Mountain fault zone, Virginia and West Virginia, USA

USGS Publications Warehouse

Orndorff, Randall C.

2012-01-01

The method of emplacement and sequential deformation of major thrust zones may be deciphered by detailed geologic mapping of these important structures. Thrust fault zones may have added complexity when horse blocks are contained within them. However, these horses can be an important indicator of the fault development holding information on fault-propagation folding or fold-to-fault progression. The North Mountain fault zone of the Central Appalachians, USA, was studied in order to better understand the relationships of horse blocks to hanging wall and footwall structures. The North Mountain fault zone in northwestern Virginia and eastern panhandle of West Virginia is the Late Mississippian to Permian Alleghanian structure that developed after regional-scale folding. Evidence for this deformation sequence is a consistent progression of right-side up to overturned strata in horses within the fault zone. Rocks on the southeast side (hinterland) of the zone are almost exclusively right-side up, whereas rocks on the northwest side (foreland) of the zone are almost exclusively overturned. This suggests that the fault zone developed along the overturned southeast limb of a syncline to the northwest and the adjacent upright limb of a faulted anticline to the southeast.

Dynamic recrystallization mechanisms and their transition in the Daling Thrust (DT) zone, Darjeeling-Sikkim Himalaya

NASA Astrophysics Data System (ADS)

Ghosh, Subhajit; Bose, Santanu; Mandal, Nibir; Dasgupta, Sujoy

2016-04-01

The Daling Thrust (DT) delineates a zone of intense shear localization in the Lesser Himalayan Sequence (LHS) of the Darjeeling-Sikkim Himalaya. From microstructural studies of deformed quartzite samples, we show a transition in the dynamic recrystallization mechanism with increasing distance from the DT, dominated by grain boundary bulging (BLG) recrystallization closest to the DT, and progressively replaced by sub-grain rotation (SGR) recrystallization away from the thrust. The transition is marked by a characteristic variation in the fractal dimension (D) of grain boundaries, estimated from the area-perimeter method. For the BLG regime, D ≈ 1.046, which decreases significantly to a value as low as 1.025 for the SGR regime. Using the available thermal data for BLG and SGR recrystallization, we infer increasing deformation temperatures away from the DT in the hanging wall. Based on the quartz piezometer our estimates reveal strong variations in the flow stress (59.00 MPa to 16.00 MPa) over a distance of 1.2 km from the DT. Deformation mechanism maps constructed for different temperatures indicate that the strain rates (10- 12 S- 1 to 10- 14 S- 1) comply with the geologically possible range. Finally, we present a mechanical model to provide a possible explanation for the cause of stress intensification along the DT.

Subsurface structural interpretation by applying trishear algorithm: An example from the Lenghu5 fold-and-thrust belt, Qaidam Basin, Northern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Pei, Yangwen; Paton, Douglas A.; Wu, Kongyou; Xie, Liujuan

2017-08-01

The application of trishear algorithm, in which deformation occurs in a triangle zone in front of a propagating fault tip, is often used to understand fault related folding. In comparison to kink-band methods, a key characteristic of trishear algorithm is that non-uniform deformation within the triangle zone allows the layer thickness and horizon length to change during deformation, which is commonly observed in natural structures. An example from the Lenghu5 fold-and-thrust belt (Qaidam Basin, Northern Tibetan Plateau) is interpreted to help understand how to employ trishear forward modelling to improve the accuracy of seismic interpretation. High resolution fieldwork data, including high-angle dips, 'dragging structures', thinning hanging-wall and thickening footwall, are used to determined best-fit trishear model to explain the deformation happened to the Lenghu5 fold-and-thrust belt. We also consider the factors that increase the complexity of trishear models, including: (a) fault-dip changes and (b) pre-existing faults. We integrate fault dip change and pre-existing faults to predict subsurface structures that are apparently under seismic resolution. The analogue analysis by trishear models indicates that the Lenghu5 fold-and-thrust belt is controlled by an upward-steepening reverse fault above a pre-existing opposite-thrusting fault in deeper subsurface. The validity of the trishear model is confirmed by the high accordance between the model and the high-resolution fieldwork. The validated trishear forward model provides geometric constraints to the faults and horizons in the seismic section, e.g., fault cutoffs and fault tip position, faults' intersecting relationship and horizon/fault cross-cutting relationship. The subsurface prediction using trishear algorithm can significantly increase the accuracy of seismic interpretation, particularly in seismic sections with low signal/noise ratio.

Active tectonic of the Medlicott Wadia Thrust (Western Himalaya) inferred from morphotectonic analysis

NASA Astrophysics Data System (ADS)

Vignon, V.; Mugnier, J. L.; Replumaz, A.; Vassallo, R.; Ramakrishnan, R.; Srivastava, P.; Malik, M. M.; Jouanne, F.; Carcaillet, J.

2010-12-01

We study the main emergence of the Main Himalayan Thrust (MHT), in the western Himalaya. The MHT is the active Indian/Asian plate boundary and is responsible for M > 8 shallow earthquakes. Its main emergence in west Himalaya occurred along the Medlicott Wadia Thrust (MWT) responsible for the 2005 M 7.6 Balakot earthquake in Pakistan. In the Riasi area, two major rivers, the Chenab and the Anji, have built large fluvial terraces across the MWT. We have mapped the geometry of the terraces and the elevation of the tectonic scarps using kinematic GPS, total station measurements and satellite imagery. The terraces have been dated combining several methods: cosmogenic-nuclide dating (10Be) on boulders constituting the terrace treads, and Optically Stimulated Luminescence (OSL) on fine-grained deposit layers. At the hanging wall of the fault, the Palaeozoic limestone bedrock is deeply incised by Chenab River that formed a series of stepped strath terraces from the present river level up to 350 m above it. We have mapped and measured the relative height of 8 terraces and of their alluvial cover. To estimate the incision rate of the hanging wall, we dated 3 terraces, situated respectively 375 m, 250m and 100m above the present day river bed. The highest terrace has a minimum exposure age of 28 ka. This yield a maximum incision rate of 1,3 cm/yr over the last 28 ka. At the foot wall of the fault, we have mapped 6 terraces deposited above tertiary foreland basin sediment (Siwalik). The most extended terrace, on which the Riasi city is built, forms the top of a more than 40 m thick aggradation sedimentary body, deposited between 16 and 14 ka. A tributary inflowing stream (Nodda River) deposited a steep alluvial fan above the active fault. Nodda River incised since ~4 ka its own deposits and provides a natural trench, revealing three splays of the Riasi thrust. Along the northern splay, Precambrian limestones are thrust over Quaternary sediments. This splay is sealed by Chenab and Nodda deposits and the last motion occurred in a syn-sedimentary context between 35-39 ka. Colluvial wedges related to ~few-meters-displacement paleoearthquakes are preserved within the sedimentary pile. The second splay cuts through the alluvial fan, leading to a scarp that increases towards East reaching more than 37-m-high. The southern splay folds the alluvial fan into a fault-cored anticline, leading to a 34-m-high scarp. These two fault segments are the most recent active structures of the MHT. With a total vertical displacement of ~70 m of a surface dated at around 14 ka the long term slip rate can be estimated between 4.5 and 9 mm/yr. This work confirms that the Medlicott Wadia Thrust is one of the main emergences of the Main Himalayan Thrust in western Himalaya and suggests that it is more active in the Riasi area than in the Balakot area. Considering a 5 centuries seismic gap on a >70 km segment, and a faulting behaviour able to generate several meters co-seismic movement, we may expect a major event in the next few decades in the Riasi region.

Fluid-rock interaction recorded in fault rocks of the Nobeoka Thrust, fossilized megasplay fault in an ancient accretionary complex

NASA Astrophysics Data System (ADS)

Hasegawa, R.; Yamaguchi, A.; Fukuchi, R.; Kitamura, Y.; Kimura, G.; Hamada, Y.; Ashi, J.; Ishikawa, T.

2017-12-01

The relationship between faulting and fluid behavior has been in debate. In this study, we clarify the fluid-rock interaction in the Nobeoka Thrust by major/trace element composition analysis using the boring core of the Nobeoka Thrust, an exhumed analogue of an ancient megasplay fault in Shimanto accretionary complex, southwest Japan. The hanging wall and the footwall of the Nobeoka Thrust show difference in lithology and metamorphic grade, and their maximum burial temperature is estimated from vitrinite reflectance analysis to be 320 330°C and 250 270°C, respectively (Kondo et al., 2005). The fault zone was formed in a fluid-rich condition, as evidenced by warm fluid migration suggested by fluid inclusion analysis (Kondo et al., 2005), implosion brecciation accompanied by carbonate precipitation followed by formation of pseudotachylyte (Okamoto et al., 2006), ankerite veins coseismically formed under reducing conditions (Yamaguchi et al., 2011), and quartz veins recording stress rotation in seismic cycles (Otsubo et al., 2016). In this study, first we analyzed the major/trace element composition across the principal slip zone (PSZ) of the Nobeoka Thrust by using fragments of borehole cores penetrated through the Nobeoka Thrust. Many elements fluctuated just above the PSZ, whereas K increase and Na, Si decrease suggesting illitization of plagioclase, as well as positive anomalies in Li and Cs were found within the PSZ. For more detail understanding, we observed polished slabs and thin sections of the PSZ. Although grain size reduction of deformed clast and weak development of foliation were observed entirely in the PSZ by macroscopic observation, remarkable development of composite planar fabric nor evidence of friction melting were absent. In this presentation, we show the result of major/trace element composition corresponding to the internal structure of PSZ, and discuss fluid-rock interaction and its impact to megasplay fault activity in subduction zones.

Experimental and numerical investigations on PDE performance augmentation by means of an ejector

NASA Astrophysics Data System (ADS)

Canteins, G.; Franzetti, F.; Zocłońska, E.; Khasainov, B. A.; Zitoun, R.; Desbordes, D.

2006-06-01

To improve the performance of pulse detonation engines, a 48 cm long cylindrical combustion chamber of 5cm internal diameter (i.d.) is fitted with an ejector of constant section. The role of the ejector is (i) to provide partial confinement of the detonation products escaping from the chamber and (ii) to suck in fresh air and then to increase the mass ejected compared to the ejection of burned gases alone. The combustion chamber is fully filled with a stoichiometric ethylene/oxygen mixture at ambient conditions. Three parameters of the ejector are varied: the i.d. D, the length L, and the position d relative to the thrust wall of the combustion chamber. For various configurations, the specific impulse ( I sp) is determined in single shot experiments. The maximum operating frequency ( f max) and the maximum thrust are then deduced. I sp is measured by means of the ballistic pendulum method, and f max is derived from the pressure signal recorded on the combustion chamber thrust wall. The addition of an ejector increases the specific impulse up to 60% in the best configuration tested, from 164s without ejector to 260s with ejector. The specific impulse can be represented by a single curve using suitable dimensionless parameters. The thrust results for the main ejector studied ( D = 80mm) indicate an optimal ( L, d) configuration that provides a 28% thrust gain. For the same ejector, f max remains constant and equal to the frequency obtained without ejector in a large range of ( L, d) values, before decreasing. Two-dimensional unsteady numerical computations agree reasonably with the experiments, slightly overestimating the experimental values. The results indicate that 80% of the I sp gain comes from the action of the expanding detonation products on the annular end surface of the combustion chamber, governed by the tube wall thickness.

Geometric and kinematic analysis of structural elements along north front of Bagharan Kuh Mountain, NE Iran

NASA Astrophysics Data System (ADS)

Samimi, S.; Gholami, E.

2017-03-01

At the end of the western part of Bagharan Kuh Mountain in the northeast of Iran, mountain growth has been stopped toward the west because of the stress having been consumed by the thrusting movements and region rising instead of shear movement. Chahkand fault zone is situated at the western part of this mountain; this fault zone includes several thrust sheets that caused upper cretaceous ophiolite rocks up to younger units, peridotite exposure and fault related fold developing in the surface. In transverse perpendicular to the mountain toward the north, reduction in the parameters like faults dip, amount of deformation, peridotite outcrops show faults growth sequence and thrust sheets growth from mountain to plain, thus structural vergence is toward the northeast in this fault zone. Deformation in the east part of the region caused fault propagation fold with axial trend of WNW-ESE that is compatible with trending of fault plane. In the middle part, two types of folds is observed; in the first type, folding occurred before faulting and folds was cut by back thrust activity; in the second type, faults activity caused fault related folds with N60-90W axial trend. In order to hanging wall strain balance, back thrusts have been developed in the middle and western part which caused popup and fault bend folds with N20-70E trend. Back thrusts activity formed footwall synclines, micro folds, foliations, and uplift in this part of the region. Kinematic analysis of faults show stress axis σ1 = N201.6, 7, σ2 = N292.6, 7.1, σ3 = N64.8, 79.5; stress axis obtained by fold analysis confirm that minimum stress (σ3) is close to vertical so it is compatible with fault analysis. Based on the results, deformation in this region is controlled by compressional stress regime. This stress state is consistent with the direction of convergence between the Arabian and Eurasian plates. Also study of transposition, folded veins, different movements on the fault planes and back thrusts confirm the progressive deformation is dominant in this region that it increases from the east to the west.

Up-dip partitioning of displacement components on the oblique-slip Clarence Fault, New Zealand

NASA Astrophysics Data System (ADS)

Nicol, Andrew; Van Dissen, Russell

2002-09-01

Active strike-slip faults in New Zealand occur within an obliquely-convergent plate boundary zone. Although the traces of these faults commonly delineate the base of mountain ranges, they do not always accommodate significant shortening at the free surface. Along the active trace of Clarence Fault in northeastern South Island, New Zealand, displaced landforms and slickenside striations indicate predominantly horizontal displacements at the ground surface, and a right-lateral slip rate of ca. 3.5-5 mm/year during the Holocene. The Inland Kaikoura mountain range occupies the hanging wall of the fault and rises steeply from the active trace to altitudes of ca. 3 km. The geomorphology of the range indicates active uplift and mountain building, which is interpreted to result, in part, from a vertical component of fault slip at depth. These data are consistent with the fault accommodating oblique-slip at depth aligned parallel to the plate-motion vector and compatible with regional geodetic data and earthquake focal-mechanisms. Oblique-slip on the Clarence Fault at depth is partitioned at the free surface into: (1) right-lateral displacement on the fault, and (2) hanging wall uplift produced by distributed displacement on small-scale faults parallel to the main fault. Decoupling of slip components reflects an up-dip transfer of fault throw to an off-fault zone of distributed uplift. Such zones are common in the hanging walls of thrusts and reverse faults, and support the idea that the dip of the oblique-slip Clarence Fault steepens towards the free surface.

Magnetic Field Tailored Annular Hall Thruster with Anode Layer

NASA Astrophysics Data System (ADS)

Lee, Seunghun; Kim, Holak; Kim, Junbum; Lim, Youbong; Choe, Wonho; Korea Institute of Materials Science Collaboration

2016-09-01

Plasma propulsion system is one of the key components for advanced missions of satellites as well as deep space exploration. A typical plasma propulsion system is Hall effect thruster that uses crossed electric and magnetic fields to ionize a propellant gas and to accelerate the ionized gas to generate momentum. In Hall thruster plasmas, magnetic field configuration is important due to the fact that electron confinement in the electromagnetic fields affects both plasma and ion beam characteristics as well as thruster performance parameters including thrust, specific impulse, power efficiency, and life time. In this work, development of an anode layer Hall thruster (TAL) with magnetic field tailoring has been attempted. The TAL is possible to keep discharge in 1 to 2 kilovolts of anode voltage, which is useful to obtain high specific impulse. The magnetic field tailoring is used to minimize undesirable heat dissipation and secondary electron emission from the wall surrounding the plasma. We will report 3 W and 200 W thrusters performances measured by a pendulum thrust stand according to the magnetic field configuration. Also, the measured result will be compared with the plasma diagnostics conducted by an angular Faraday probe, a retarding potential analyzer, and a ExB probe.

Magnitude, Timing, and Geometry of Extension in the Southern Sevier Desert Basin From Piercing Points, Seismic-Stratigraphic Reconstruction, and Deep well Data

NASA Astrophysics Data System (ADS)

Coogan, J. C.; Decelles, P. G.

2007-12-01

Palinspastic reconstruction of Mesozoic thrust sheets provides the main constraint for an estimated 47 km of Cenozoic extensional displacement along the Sevier Desert detachment (SDD) in the central Sevier Desert Basin. Hanging wall and footwall piercing points indicate that the SDD accommodated a minimum of 35 km of extensional displacement in the narrower southern part of the basin. The piercing points for the SDD are defined by the intersection of the SDD, the Canyon Range thrust (CRT), and a regional early Cenozoic erosion surface (ES). The hanging wall piercing point lies immediately northeast of the Cricket Mountains, where the SDD-CRT- ES intersection is narrowly defined by intersecting structure maps derived from published seismic reflection data. The footwall piercing point lies in the southern foothills of the Canyon Range, where the SDD breakaway plane is well constrained by an industry seismic line that lies within 2 km of the exposed intersection of the CRT with the base of the Oligocene Oak City Formation. Timing of extension in the southern Sevier Desert basin is constrained by a kinematic reconstruction of detachment and imbricate fault displacement, footwall uplift, and supradetachment sedimentation for Oligocene, Miocene, and Plio-Pleistocene seismic sequences. The reconstruction is centered on a seismic reflection and gravity interpretation along the published Pan Canadian profiles 2 and 3 that is tied to dated intervals in six industry wells. Fault restoration indicates that Oligocene and Miocene phases of slip each accounted for about 40 percent of the total displacement. Simultaneous backstripping of the Oligocene, Miocene, and Plio-Pleistocene supradetachment sequences records hanging wall subsidence simultaneous with footwall uplift, with a footwall burial history that is consistent with published Miocene apatite and zircon fission-track ages of footwall samples. The geometric evolution of the southern SDD extensional system is consistent with its development above a broad westward-migrating "rolling hinge" zone associated with isostatic uplift of the detachment footwall. Hanging wall normal faults east of the footwall crest exhibit small post-Miocene displacement, with demonstrable Quaternary slip restricted to the crest and western limb of the uplift, most notably along the Black Rock and Clear Lake fault zones. Early abandonment of the eastern part of the detachment may explain the indistinct geomorphic and structural expression of the break-away zone at the surface. The deepest level of the southern SDD also presents a complex geometry and kinematic history. The 1996 Chevron 1-29 Black Rock Federal well through the western basin margin penetrated a normal fault that places Jurassic over lower Cambrian strata at 4650 m measured depth, well above the principal SDD seismic reflection. The fault is not correlated to any large- displacement high-angle fault at shallow levels, and may form the abandoned roof to an extensional duplex.

Responding to Mechanical Antigravity

NASA Technical Reports Server (NTRS)

Millis, Marc G.; Thomas, Nicholas E.

2006-01-01

Based on the experiences of the NASA Breakthrough Propulsion Physics Project, suggestions are offered for constructively responding to proposals that purport breakthrough propulsion using mechanical devices. Because of the relatively large number of unsolicited submissions received (about 1 per workday) and because many of these involve similar concepts, this report is offered to help the would-be submitters make genuine progress as well as to help reviewers respond to such submissions. Devices that use oscillating masses or gyroscope falsely appear to create net thrust through differential friction or by misinterpreting torques as linear forces. To cover both the possibility of an errant claim and a genuine discovery, reviews should require that submitters meet minimal thresholds of proof before engaging in further correspondence; such as achieving sustained deflection of a level-platform pendulum in the case of mechanical thrusters.

Helicopter vibration suppression using simple pendulum absorbers on the rotor blade

NASA Technical Reports Server (NTRS)

Pierce, G. A.; Hanouva, M. N. H.

1982-01-01

A comprehensive anaytical design procedure for the installation of simple pendulums on the blades of a helicopter rotor to suppress the root reactions is presented. A frequency response anaysis is conducted of typical rotor blades excited by a harmonic variation of spanwise airload distributions as well as a concentrated load at the tip. The results presented included the effect of pendulum tuning on the minimization of the hub reactions. It is found that a properly designed flapping pendulum attenuates the root out-of-plane force and moment whereas the optimum designed lead-lag pendulum attenuates the root in-plane reactions. For optimum pendulum tuning the parameters to be determined are the pendulum uncoupled natural frequency, the pendulum spanwise location and its mass. It is found that the optimum pendulum frequency is in the vicinity of the excitation frequency. For the optimum pendulum a parametric study is conducted. The parameters varied include prepitch, pretwist, precone and pendulum hinge offset.

Optical Kapitza pendulum

NASA Astrophysics Data System (ADS)

Jones, Philip H.; Smart, Thomas J.; Richards, Christopher J.; Cubero, David

2016-09-01

The Kapitza pendulum is the paradigm for the phenomenon of dynamical stabilization, whereby an otherwise unstable system achieves a stability that is induced by fast modulation of a control parameter. In the classic, macroscopic Kapitza pendulum, a rigid pendulum is stabilized in the upright, inverted pendulum using a particle confined in a ring-shaped optical trap, subject to a drag force via fluid flow and driven via oscillating the potential in a direction parallel to the fluid flow. In the regime of vanishing Reynold's number with high-frequency driving the inverted pendulum is no longer stable, but new equilibrium positions appear that depend on the amplitude of driving. As the driving frequency is decreased a yet different behavior emerges where stability of the pendulum depends also on the details of the pendulum hydrodynamics. We present a theory for the observed induced stability of the overdamped pendulum based on the separation of timescales in the pendulum motion as formulated by Kapitza, but with the addition of a viscous drag. Excellent agreement is found between the predicted behavior from the analytical theory and the experimental results across the range of pendulum driving frequencies. We complement these results with Brownian motion simulations, and we characterize the stabilized pendulum by both time- and frequency-domain analyses of the pendulum Brownian motion.

A Personal Navigation System Based on Inertial and Magnetic Field Measurements

DTIC Science & Technology

2010-09-01

MATLAB IMPLEMENTATION.................................................................74 G. A MODEL FOR PENDULUM MOTION SENSOR DATA...76 1. Pendulum Model for MATLAB Simulation....................................76 2. Sensor Data Generated with the Pendulum Model... PENDULUM ..................................................................................................88 I. FILTER PERFORMANCE WITH REAL PENDULUM DATA

Broadband pendulum energy harvester

NASA Astrophysics Data System (ADS)

Liang, Changwei; Wu, You; Zuo, Lei

2016-09-01

A novel electromagnetic pendulum energy harvester with mechanical motion rectifier (MMR) is proposed and investigated in this paper. MMR is a mechanism which rectifies the bidirectional swing motion of the pendulum into unidirectional rotation of the generator by using two one-way clutches in the gear system. In this paper, two prototypes of pendulum energy harvester with MMR and without MMR are designed and fabricated. The dynamic model of the proposed MMR pendulum energy harvester is established by considering the engagement and disengagement of the one way clutches. The simulation results show that the proposed MMR pendulum energy harvester has a larger output power at high frequencies comparing with non-MMR pendulum energy harvester which benefits from the disengagement of one-way clutch during pendulum vibration. Moreover, the proposed MMR pendulum energy harvester is broadband compare with non-MMR pendulum energy harvester, especially when the equivalent inertia is large. An experiment is also conducted to compare the energy harvesting performance of these two prototypes. A flywheel is attached at the end of the generator to make the disengagement more significant. The experiment results also verify that MMR pendulum energy harvester is broadband and has a larger output power at high frequency over the non-MMR pendulum energy harvester.

Dynamic characteristics of rotor blades with pendulum absorbers

NASA Technical Reports Server (NTRS)

Murthy, V. R.; Goglia, G. L.

1977-01-01

The point transmission matrix for a vertical plane pendulum on a rotating blade undergoing combined flapwise bending, and chordwise bending and torsion is derived. The equilibrium equation of the pendulum is linearized for small oscillations about the steady state. A FORTRAN program was written for the case of a vertical plane pendulum attached to a uniform blade with flapwise bending degree of freedom for cantilever boundary conditions. The frequency has a singular value right at the uncoupled pendulum natural frequency and thus introduces two frequencies corresponding to the nearest natural frequency of the blade without pendulum. In both of these modes it was observed that the pendulum deflection is large. One frequency can be thought of as a coupled pendulum frequency and the other as a coupled bending and pendulum frequency.

Mesozoic contractile and extensional structures in the Boyer Gap area, northern Dome Rock Mountains, Arizona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boettcher, S.S.

1993-04-01

Mesozoic polyphase contractile and superposed ductile extensional structures affect Proterozoic augen gneiss, Paleozoic metasedimentary rocks, and Jurassic granitoids in the Boyer Gap area of the northern Dome Rock Mtns, W-central Arizona. The nappe-style contractile structures are preserved in the footwall of the Tyson Thrust shear zone, which is one of the structurally lowest thrust faults in the E-trending Jurassic and Cretaceous Maria fold and thrust belt. Contractile deformation preceded emplacement of Late Cretaceous granite (ca 80 Ma, U-Pb zircon) and some may be older than variably deformed Late Jurassic leucogranite. Specifically, detailed structural mapping reveals the presence of a km-scalemore » antiformal syncline that apparently formed as a result of superposition of tight to isoclinal, south-facing folds on an earlier, north-facing recumbent fold. The stratigraphic sequence of metamorphosed Paleozoic cratonal strata is largely intact in the northern Dome Rock Mtns, such that overturned and upright stratigraphic units can be distinguished. A third phase of folding in the Boyer Gap area is distinguished by intersection lineations that are folded obliquely across the hinges of open to tight, sheath folds. The axial planes of the sheet folds are subparallel to the mylonitic foliation in top-to-the-northeast extensional shear zones. The timing of ductile extensional structures in the northern Dome Rock is constrained by [sup 40]Ar/[sup 39]Ar isochron ages of 56 Ma and 48 Ma on biotite from mylonitic rocks in both the hanging wall and footwall of the Tyson Thrust shear zone. The two early phases of folding are the dominant mechanism by which shortening was accommodated in the Boyer Gap area, as opposed to deformation along discrete thrust faults with large offset. All of the ductile extensional structures are spectacularly displayed at an outcrop scale but are not of sufficient magnitude to obliterate the km-scale Mesozoic polyphase contractile structures.« less

Core-Log-Seismic Integrative Study of a Subduction Zone Megasplay Fault -An Example from the Nobeoka Thrust, Shimanto Belt, Southwest Japan

NASA Astrophysics Data System (ADS)

Hamahashi, M.; Tsuji, T.; Saito, S.; Tanikawa, W.; Hamada, Y.; Hashimoto, Y.; Kimura, G.

2016-12-01

Investigating the mechanical properties and deformation patterns of megathrusts in subduction zones is important to understand the generation of large earthquakes. The Nobeoka Thrust, a fossilized megasplay fault in Kyushu Shimanto Belt, southwest Japan, exposes foliated fault rocks that were formed under the temperature range of 180-350° (Kondo et al., 2005). During the Nobeoka Thrust Drilling Project (2011), core samples and geophysical logging data were obtained recovering a continuous distribution of multiple fault zones, which provide the opportunity to examine their structure and physical properties in various scales (Hamahashi et al., 2013; 2015). By performing logging data analysis, discrete sample physical property measurements, and synthetic modeling of seismic reflections along the Nobeoka Thrust, we conducted core-log-seismic integrative study to characterize the effects of damage zone architecture and structural anisotropy towards the physical properties of the megasplay. A clear contrast in physical properties across the main fault core and surrounding damage zones were identified, where the fault rocks preserve the porosity of 4.8% in the hanging wall and 7.6% in the footwall, and P-wave velocity of 4.8 km/s and 4.2 km/s, respectively. Multiple sandstone-rich- and shale-rich damage zones were found from the drilled cores, in which velocity decreases significantly in the brecciated zones. The internal structure of these foliated fault rocks consist of heterogeneous lithology and texture, and velocity anisotropy ranges 1-18% (P-wave) and 1.5-80% (S-wave), affected by structural dip angle, foliation density, and sandstone/mudstone ratio. To evaluate the fault properties at the seismogenic depth, we developed velocity/earth models and synthetic modeling of seismic reflection using acoustic logs across the thrust and parameterized lithological and structural elements in the identified multiple damage zones.

Cold seeps and splay faults on Nankai margin

NASA Astrophysics Data System (ADS)

Henry, P.; Ashi, J.; Tsunogai, U.; Toki, T.; Kuramoto, S.; Kinoshita, M.; Lallemant, S. J.

2003-04-01

Cold seeps (bacterial mats, specific fauna, authigenic carbonates) are common on the Nankai margin and considered as evidence for seepage of methane bearing fluids. Camera and submersible surveys performed over the years have shown that cold seeps are generally associated with active faults. One question is whether part of the fluids expelled originate from the seismogenic zone and migrate along splay faults to the seafloor. The localisation of most cold seeps on the hanging wall of major thrusts may, however, be interpreted in various ways: (a) footwall compaction and diffuse flow (b) fluid channelling along the fault zone at depths and diffuse flow near the seafloor (c) erosion and channelling along permeable strata. In 2002, new observations and sampling were performed with submersible and ROV (1) on major thrusts along the boundary between the Kumano forearc basin domain and the accretionary wedge domain, (2) on a fault affecting the forearc (Kodaiba fault), (3) on mud volcanoes in the Kumano basin. In area (1) tsunami and seismic inversions indicate that the targeted thrusts are in the slip zone of the To-Nankai 1944 earthquakes. In this area, the largest seep zone, continuous over at least 2 km, coincides with the termination of a thrust trace, indicating local fluid channelling along the edge of the fault zone. Kodaiba fault is part of another splay fault system, which has both thrusting and strike-slip components and terminates westward into an en-echelon fold system. Strong seepage activity with abundant carbonates was found on a fold at the fault termination. One mud volcano, rooted in one of the en-echelon fold, has exceptionally high seepage activity compared with the others and thick carbonate crusts. These observations suggest that fluid expulsion along fault zones is most active at fault terminations and may be enhanced during fault initiation. Preliminary geochemical results indicate signatures differ between seep sites and suggests that the two fault systems tap in different sources.

Fault propagation folds induced by gravitational failure and slumping of the Central Costa Rica volcanic range: Implications for large terrestrial and Martian volcanic edifices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borgia, A.; Burr, J.; Montero, W.

1990-08-30

Long sublinear ridges and related scarps located at the base of large volcanic structures are frequently interpreted as normal faults associated with extensional regional stress. In contrast, the ridges bordering the Central Costa Rica volcanic range (CCRVR) are the topographic expression of hanging wall asymmetric angular anticlines overlying low-angle thrust faults at the base of the range. These faults formed by gravitational failure and slumping of the flanks of the range due to the weight of the volcanic edifices and were perhaps triggered by the intrusion of magma over the past 20,000 years. These anticlines are hypothesized to occur alongmore » the base of the volcano, where the thrust faults ramp up toward the sea bottom. Ridges and scarps between 2,000 and 5,000 m below sea level are interpreted as the topographic expression of these folds. The authors further suggest that the scarps of the CCRVR and valid scaled terrestrial analogs of the perimeter scarp of the Martian volcano Olympus Mons. They suggest that the crust below Olympus Mons has failed under the load of the volcano, triggering the radial slumping of the flanks of the volcano on basal thrusts. The thrusting would have, in turn, formed the anticlinal ridges and scarps that surround the edifice. The thrust faults may extend all the way to the base of the Martian crust (about 40 km), and they may have been active until almost the end of the volcanic activity. They suggest that gravitational failure and slumping of the flanks of volcanoes is a process common to most large volcanic edifices. In the CCRVR this slumping of the flanks is a slow intermittent process, but it could evolve to rapid massive avalanching leading to catastrophic eruptions. Thus monitoring of uplift and displacement of the folds related to the slump tectonics could become an additional effective method for mitigating volcanic hazards.« less

The effect of complex fault rupture on the distribution of landslides triggered by the 12 January 2010, Haiti earthquake

USGS Publications Warehouse

Harp, Edwin L.; Jibson, Randall W.; Dart, Richard L.; Margottini, Claudio; Canuti, Paolo; Sassa, Kyoji

2013-01-01

The MW 7.0, 12 January 2010, Haiti earthquake triggered more than 7,000 landslides in the mountainous terrain south of Port-au-Prince over an area that extends approximately 50 km to the east and west from the epicenter and to the southern coast. Most of the triggered landslides were rock and soil slides from 25°–65° slopes within heavily fractured limestone and deeply weathered basalt and basaltic breccia. Landslide volumes ranged from tens of cubic meters to several thousand cubic meters. Rock slides in limestone typically were 2–5 m thick; slides within soils and weathered basalt typically were less than 1 m thick. Twenty to thirty larger landslides having volumes greater than 10,000 m3 were triggered by the earthquake; these included block slides and rotational slumps in limestone bedrock. Only a few landslides larger than 5,000 m3 occurred in the weathered basalt. The distribution of landslides is asymmetric with respect to the fault source and epicenter. Relatively few landslides were triggered north of the fault source on the hanging wall. The densest landslide concentrations lie south of the fault source and the Enriquillo-Plantain-Garden fault zone on the footwall. Numerous landslides also occurred along the south coast west of Jacmél. This asymmetric distribution of landsliding with respect to the fault source is unusual given the modeled displacement of the fault source as mainly thrust motion to the south on a plane dipping to the north at approximately 55°; landslide concentrations in other documented thrust earthquakes generally have been greatest on the hanging wall. This apparent inconsistency of the landslide distribution with respect to the fault model remains poorly understood given the lack of any strong-motion instruments within Haiti during the earthquake.

Crustal implications of bedrock geology along the Trans-Alaska Crustal Transect (TACT) in the Brooks Range, northern Alaska

USGS Publications Warehouse

Moore, Thomas E.; Wallace, W.K.; Mull, C.G.; Adams, K.E.; Plafker, G.; Nokleberg, W.J.

1997-01-01

Geologic mapping of the Trans-Alaska Crustal Transect (TACT) project along the Dalton Highway in northern Alaska indicates that the Endicott Mountains allochthon and the Hammond terrane compose a combined allochthon that was thrust northward at least 90 km in the Early Cretaceous. The basal thrust of the combined allochthon climbs up section in the hanging wall from a ductile shear zone, in the south through lower Paleozoic rocks of the Hammond terrane and into Upper Devonian rocks of the Endicott Mountains allochthon at the Mount Doonerak antiform, culminating in Early Cretaceous shale in the northern foothills of the Brooks Range. Footwall rocks north of the Mount Doonerak antiform are everywhere parautochthonous Permian and Triassic shale of the North Slope terrane rather than Jurassic and Lower Cretaceous strata of the Colville Basin as shown in most other tectonic models of the central Brooks Range. Stratigraphic and structural relations suggest that this thrust was the basal detachment for Early Cretaceous deformation. Younger structures, such as the Tertiary Mount Doonerak antiform, deform the Early Cretaceous structures and are cored by thrusts that root at a depth of about 10 to 30 km along a deeper detachment than the Early Cretaceous detachment. The Brooks Range, therefore, exposes (1) an Early Cretaceous thin-skinned deformational belt developed during arc-continent collision and (2) a mainly Tertiary thick-skinned orogen that is probably the northward continuation of the Rocky Mountains erogenic belt. A down-to-the-south zone of both ductile and brittle normal faulting along the southern margin of the Brooks Range probably formed in the mid-Cretaceous by extensional exhumation of the Early Cretaceous contractional deformation. copyright. Published in 1997 by the American Geophysical Union.

The 2015 April 25 Gorkha Earthquake and its Aftershocks: Implications for lateral heterogeneity on the Main Himalayan Thrust

NASA Astrophysics Data System (ADS)

Mitra, S.; Kumar, A.; Priestley, K. F.

2016-12-01

The 2015 Gorkha earthquake (Mw 7.8) occurred by thrust faulting on a ˜150 km long and ˜70 km wide, locked downdip segment of the Main Himalayan Thrust (MHT), causing the Himalaya to slip SSW over the Indian Plate, and was followed by major-to-moderate aftershocks. Back projection of teleseismic P-wave and inversion of teleseismic body waves provide constraints on the geometry and kinematics of the mainshock rupture and source mechanism of aftershocks. The mainshock initiated ˜80 km west of Katmandu, close to the locking line on the MHT and propagated eastwards, along ˜117° azimuth, for a duration of ˜70 s, in multi-stage rupture. The mainshock has been modeled using four sub-events, propagating from west-to-east. The first sub-event (0-20 s) ruptured at a velocity of ˜3.5 km/s on a ˜6° N dipping flat segment of the MHT with thrust motion. The second sub-event (20-35 s) ruptured a ˜18° W dipping lateral ramp on the MHT in oblique thrust motion. The rupture velocity dropped from 3.5 km/s to 2.5 km/s, as a result of updip propagation of the rupture. The third sub-event (35-50 s) ruptured a ˜7° N dipping, eastward flat segment of the MHT with thrust motion and resulted in the largest amplitude arrivals at teleseismic distances. The fourth sub-event (50-70 s) occurred by left-lateral strike-slip motion on a steeply dipping transverse fault, at high angle to the MHT and arrested the eastward propagation of the mainshock rupture. Eastward stress build-up following the mainshock resulted in the largest aftershock (Mw 7.3), which occurred on the MHT, immediately east of the mainshock rupture. Source mechanism of moderate aftershocks reveal stress adjustment at the edges of the mainshock fault, flexural faulting on top of the downgoing Indian Plate and extensional faulting in the hanging wall of the MHT.

The 2015 April 25 Gorkha (Nepal) earthquake and its aftershocks: implications for lateral heterogeneity on the Main Himalayan Thrust

NASA Astrophysics Data System (ADS)

Kumar, Ajay; Singh, Shashwat K.; Mitra, S.; Priestley, K. F.; Dayal, Shankar

2017-02-01

The 2015 Gorkha earthquake (Mw 7.8) occurred by thrust faulting on a ˜150 km long and ˜70 km wide, locked downdip segment of the Main Himalayan Thrust (MHT), causing the Himalaya to slip SSW over the Indian Plate, and was followed by major-to-moderate aftershocks. Back projection of teleseismic P-wave and inversion of teleseismic body waves provide constraints on the geometry and kinematics of the main-shock rupture and source mechanism of aftershocks. The main-shock initiated ˜80 km west of Katmandu, close to the locking line on the MHT and propagated eastwards along ˜117° azimuth for a duration of ˜70 s, with varying rupture velocity on a heterogeneous fault surface. The main-shock has been modelled using four subevents, propagating from west-to-east. The first subevent (0-20 s) ruptured at a velocity of ˜3.5 km s- 1 on a ˜6°N dipping flat segment of the MHT with thrust motion. The second subevent (20-35 s) ruptured a ˜18° W dipping lateral ramp on the MHT in oblique thrust motion. The rupture velocity dropped from 3.5 km s- 1 to 2.5 km s- 1, as a result of updip propagation of the rupture. The third subevent (35-50 s) ruptured a ˜7°N dipping, eastward flat segment of the MHT with thrust motion and resulted in the largest amplitude arrivals at teleseismic distances. The fourth subevent (50-70 s) occurred by left-lateral strike-slip motion on a steeply dipping transverse fault, at high angle to the MHT and arrested the eastward propagation of the main-shock rupture. Eastward stress build-up following the main-shock resulted in the largest aftershock (Mw 7.3), which occurred on the MHT, immediately east of the main-shock rupture. Source mechanisms of moderate aftershocks reveal stress adjustment at the edges of the main-shock fault, flexural faulting on top of the downgoing Indian Plate and extensional faulting in the hanging wall of the MHT.

Evaluation of Alternative Seismic Source Characterization Models for the Inner Borderlands of Southern California

NASA Astrophysics Data System (ADS)

Hanson, K. L.; Angell, M.; Foxall, W.; Rietman, J.

2002-12-01

Alternative source characterizations for seismic hazard analysis are developed to capture the range of plausible fault geometries and interactions between postulated thrusts (i.e., the Oceanside blind thrust (OBT) and San Joaquin Hills blind fault (SJBF)) and strike-slip faults (Rose Canyon (RC)-Newport Inglewood (NI) faults) along the Southern California inner borderlands. Evaluation of 2D and high-resolution shallow seismic data show evidence for a relatively continuous zone of deformation (OZD) linking the RC and NI, both of which are active strike-slip faults, based on seismicity and paleoseismic data. Geodetic data are consistent with NNW-shear and show little or no convergence across the inner borderland, or evidence of a regional "driving" force that would reactivate a large seismogenic thrust (see Moriwaki and others, this volume). Fault and fold deformation observed along the OZD between the RC and NI is consistent with transpressional right lateral slip along a N20W-trending fault zone. Evidence to support reactivation of the entire OBT in the current tectonic environment is not demonstrated. Seismicity and possible late Pleistocene/Holocene reverse faults and associated folding can be explained by localized contraction in left steps or bends in a transpressional right-slip tectonic environment. Clockwise rotation of crustal blocks in the inner borderland (which is not inconsistent with geodetic data suggesting a component of extension across the southern inner borderland) could account for the greater intensity of contractional structures in the hanging wall of the northern OBT west of the OZD. This might explain the local reactivation of portions of the OBT, but would not require reactivation of the entire detachment. Much of the contractional deformation observed in the inner borderland (e.g., the San Mateo thrust belt) could have occurred during the Pliocene. Regional coastal uplift, which has been cited as evidence that the Oceanside and Thirtymile Bank thrusts are active on a regional basis, may be attributed to other processes, such as rift shoulder thermal isostasy (e.g., Kier et.al, Tectonics 2002). We present relative weights for three alternative source models that consider a throughgoing strike-slip fault system (inactive OBT), a regional blind thrust (OBT), or an oblique fault in which strain is partitioned updip onto a strike-slip (offshore strike-slip fault) and reactivated thrust (OBT).

Balanced sections and the propagation of décollement: A Jura perspective

NASA Astrophysics Data System (ADS)

Laubscher, Hans

2003-12-01

The propagation of thrusting is an important problem in tectonics that is usually approached by forward (kinematical) modeling of balanced sections. Although modeling techniques are similar in most foreland fold-thrust belts, it turns out that in the Jura, there are modeling problems that require modifications of widely used techniques. In particular, attention is called to the role of model constraints that complement the set of observational constraints in order to fully define the model. In the eastern Jura, such model constraints may be inferred from the regional geology, which shows a peculiar noncoaxial relation between thrusts and subsequent folds. This relation implies changes in the direction of translation and the mode of deformation in the course of the propagation of décollement. These changes are conjectured to be the result of a change in partial decoupling between the thin-skinned fold-thrust system (nappe) and the obliquely subducted foreland. As a particularly instructive case in point, a cross section through the Weissenstein range is discussed. A two-step forward (kinematical) model is proposed that uses both local observational constraints as well as model constraints inferred from regional data. As a first step, a fault bend fold is generated in the hanging wall of a thrust of 1500 m shortening. As a second step, this structure is transferred by flexural slip into the actual fold observed at the surface. This requires an additional 1600 m of shortening and leads to folding of the original thrust. Thereafter, the footwall is deformed so as to respect the constraint that this deformation must fit into the space defined by the folded thrust as the upper boundary and the décollement surface as the lower boundary, and that, in addition, should be confined to the area immediately below the fold. In modeling the footwall deformation a mix of balancing methods is used: fault propagation folds for the competent intervals of the stratigraphic column and area balancing for the incompetent ones. Further propagation of décollement into the foreland is made possible by the folding process, which is dominated by a sort of kinking and which is the main contribution to structural elevation and hence to producing a sort of critical taper of the moving thin-skinned wedge.

Measuring g with a classroom pendulum using changes in the pendulum string length

NASA Astrophysics Data System (ADS)

Oliveira, V.

2016-11-01

This frontline presents a simple apparatus for measuring the acceleration of gravity using a classroom pendulum. Instead of the traditional method where the pendulum period is measured as a function of its length, here the period is measured as a function of changes in the pendulum string length. The major advantage of this method is that students can measure these changes with a greater accuracy than measuring the total pendulum length.

Strain softening along the MCT zone from the Sikkim Himalaya: Relative roles of Quartz and Micas

NASA Astrophysics Data System (ADS)

Bhattacharyya, Kathakali; Mitra, Gautam

2011-06-01

In the Darjeeling - Sikkim Himalaya, two distinct faults form the Main Central thrust (MCT), the structurally higher MCT1 and the lower MCT2; each has accommodated translation greater than 100 km. The lower MCT2 places Greater Himalayan amphibolite grade Paro-Lingtse gneiss over Lesser Himalayan greenschist grade Daling metapelites. The MCT2 is folded by the underlying Lesser Himalayan duplex and is exposed at different structural positions of the fold. At Pelling, the MCT2 zone is exposed as a ˜373 m thick NW dipping fault zone that exposes ˜19 m of hanging wall mylonitized Lingtse gneiss. The Lingtse protolith shows evidence of amphibolite grade plastic deformation features in quartz and feldspar. Within the hanging wall mylonite zone (HWMZ), quartz and feldspar have undergone grain-size reduction by different deformation mechanisms and feldspars are sericitized suggesting the presence of fluids during deformation. We estimate a temperature of ˜300 °C within the fault zone during fluid-assisted retrogression and deformation. Reaction softening of feldspars produced a large proportion of intrinsically weak matrix. This, in combination with development of a strong foliation defined by parallel mica grains, resulted in strain softening along the MCT2 zone, and concentrated the deformation along a thin zone or zones.

Post-Seismic Deformation from the 2009 Mw 6.3 Dachaidan Earthquake in the Northern Qaidam Basin Detected by Small Baseline Subset InSAR Technique

PubMed Central

Liu, Yang; Xu, Caijun; Wen, Yangmao; Li, Zhicai

2016-01-01

On 28 August 2009, one thrust-faulting Mw 6.3 earthquake struck the northern Qaidam basin, China. Due to the lack of ground observations in this remote region, this study presents high-precision and high spatio-temporal resolution post-seismic deformation series with a small baseline subset InSAR technique. At the temporal scale, this changes from fast to slow with time, with a maximum uplift up to 7.4 cm along the line of sight 334 days after the event. At the spatial scale, this is more obvious at the hanging wall than that at the footwall, and decreases from the middle to both sides at the hanging wall. We then propose a method to calculate the correlation coefficient between co-seismic and post-seismic deformation by normalizing them. The correlation coefficient is found to be 0.73, indicating a similar subsurface process occurring during both phases. The results indicate that afterslip may dominate the post-seismic deformation during 19–334 days after the event, which mainly occurs with the fault geometry and depth similar to those of the c-seismic rupturing, and partly extends to the shallower and deeper depths. PMID:26861330

Post-Seismic Deformation from the 2009 Mw 6.3 Dachaidan Earthquake in the Northern Qaidam Basin Detected by Small Baseline Subset InSAR Technique.

PubMed

Liu, Yang; Xu, Caijun; Wen, Yangmao; Li, Zhicai

2016-02-05

On 28 August 2009, one thrust-faulting Mw 6.3 earthquake struck the northern Qaidam basin, China. Due to the lack of ground observations in this remote region, this study presents high-precision and high spatio-temporal resolution post-seismic deformation series with a small baseline subset InSAR technique. At the temporal scale, this changes from fast to slow with time, with a maximum uplift up to 7.4 cm along the line of sight 334 days after the event. At the spatial scale, this is more obvious at the hanging wall than that at the footwall, and decreases from the middle to both sides at the hanging wall. We then propose a method to calculate the correlation coefficient between co-seismic and post-seismic deformation by normalizing them. The correlation coefficient is found to be 0.73, indicating a similar subsurface process occurring during both phases. The results indicate that afterslip may dominate the post-seismic deformation during 19-334 days after the event, which mainly occurs with the fault geometry and depth similar to those of the c-seismic rupturing, and partly extends to the shallower and deeper depths.

A remote sensing study of active folding and faulting in southern Kerman province, S.E. Iran

NASA Astrophysics Data System (ADS)

Walker, Richard Thomas

2006-04-01

Geomorphological observations reveal a major oblique fold-and-thrust belt in Kerman province, S.E. Iran. The active faults appear to link the Sabzevaran right-lateral strike-slip fault in southeast Iran to other strike-slip faults within the interior of the country and may provide the means of distributing right-lateral shear between the Zagros and Makran mountains over a wider region of central Iran. The Rafsanjan fault is manifest at the Earth's surface as right-lateral strike-slip fault scarps and folding in alluvial sediments. Height changes across the anticlines, and widespread incision of rivers, are likely to result from hanging-wall uplift above thrust faults at depth. Scarps in recent alluvium along the northern margins of the folds suggest that the thrusts reach the surface and are active at the present-day. The observations from Rafsanjan are used to identify similar late Quaternary faulting elsewhere in Kerman province near the towns of Mahan and Rayen. No instrumentally recorded destructive earthquakes have occurred in the study region and only one historical earthquake (Lalehzar, 1923) is recorded. In addition GPS studies show that present-day rates of deformation are low. However, fault structures in southern Kerman province do appear to be active in the late Quaternary and may be capable of producing destructive earthquakes in the future. This study shows how widely available remote sensing data can be used to provide information on the distribution of active faulting across large areas of deformation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montgomery, S.L.

Recent discovery of natural gas in sandstones of the Jackfork Group of southeastern Oklahoma has led to revised interpretations of hydrocarbon potential in the Ouachita thrust province of eastern Oklahoma. Jackfork reservoirs consist of fine to very fine grained, submarine-fan lobe sandstones with low matrix permeability and porosity. Production is dependent upon natural fractures, enhanced in most cases by artificial stimulation. Individual wells have produced at rates of 1.3-5.7 Mcf per day and possess estimated reserves in the range of 2.0-7.6 Gcf. Hyperbolic decline suggests gas contribution from the matrix, possibly due to the presence of microfractures. Drilling has concentratedmore » on two subsidiary thrust blocks in the hanging wall of the Ti Valley thrust, southern Latimer County. However, recent outcrop, petrographic, and sedimentological analyses have shown that traditional depositional models of the Jackfork are overly limited and that potential Jackfork reservoirs exist across a broad area to the south of the current play. Such analyses have revealed the existence of thick, medium-coarse-grained channel sequences at a number of localities in the Lynn Mountain syncline. Similar sequences may also exist well to the south, in the Boktukola syncline, where thick sand intervals have been identified. Petrographic study of samples from the Lynn Mountain syncline suggests that channel sequences may have significantly higher reservoir quality than is found in productive Jackfork sandstones to the north. Traditional assumptions postulating low regional hydrocarbon potential for the Jackfork therefore stand in need of revision.« less

A new class of compact high sensitive tiltmeter based on the UNISA folded pendulum mechanical architecture

NASA Astrophysics Data System (ADS)

Barone, Fabrizio; Giordano, Gerardo

2018-02-01

We present the Extended Folded Pendulum Model (EFPM), a model developed for a quantitative description of the dynamical behavior of a folded pendulum generically oriented in space. This model, based on the Tait-Bryan angular reference system, highlights the relationship between the folded pendulum orientation in the gravitational field and its natural resonance frequency. Tis model validated by tests performed with a monolithic UNISA Folded Pendulum, highlights a new technique of implementation of folded pendulum based tiltmeters.

Experiment with Conical Pendulum

ERIC Educational Resources Information Center

Tongaonkar, S. S.; Khadse, V. R.

2011-01-01

Conical pendulum is similar to simple pendulum with the difference that the bob, instead of moving back and forth, swings around in a horizontal circle. Thus, in a conical pendulum the bob moves at a constant speed in a circle with the string tracing out a cone. This paper describes an experiment with conical pendulum, with determination of g from…

Response of Pendulums to Translational and Rotational Components of Ground Motion

NASA Astrophysics Data System (ADS)

Graizer, V.; Kalkan, E.

2008-12-01

Dynamic response of most seismological instruments and many engineering structures to ground shaking can be represented via response of a pendulum (single-degree-of-freedom oscillator). Pendulum response is usually simplified by considering the input from uni-axial translational motion only. Complete ground motion however, includes not only translational components but also rotations (tilt and torsion). We consider complete equations of motion for three following types of pendulum: (i) conventional mass-on-rod, (ii) mass- on-spring type, and (iii) inverted (astatic), then their response sensitivities to each component of complex ground motion are examined. Inverted pendulums are used in seismology for more than 100 years, for example, classical Wiechert's horizontal seismograph built around 1905 and still used at some seismological observatories, and recent Guralp's horizontal seismometers CMG-40T and CMG-3T. Inverted pendulums also have significant importance for engineering applications where they are often used to simulate the dynamic response of various structural systems. The results of this study show that a horizontal pendulum similar to a modern accelerometer used in strong motion measurements is practically sensitive to translational motion and tilt only, while inverted pendulum is sensitive not only to translational components, but also to angular accelerations and tilt. For better understanding of the inverted pendulum's dynamic behavior under complex ground excitation, relative contribution of each component of motion on response variants is carefully isolated. The responses of pendulums are calculated in time-domain using close-form solution Duhamel's integral with complex input forcing functions. As compared to a common horizontal pendulum, response of an inverted pendulum is sensitive to acceleration of gravity and vertical acceleration when it reaches the level close to 1.0 g. Gravity effect introduces nonlinearity into the differential equation of motion, and results in shift of the frequency response to lower frequencies. The equations of inverted pendulum represent elastic response of pendulums (as material behavior), with nonlinearity created by time and amplitude dependence of equation coefficients. Sensitivity of inverted pendulum to angular acceleration of tilt is proportional to the length of a pendulum, and should be taken into consideration since it can produce significant effect especially for long pendulums, idealizing for instance, bridge piers, bents, elevated water tanks, telecommunication towers, etc.

Late Quaternary Arc-parallel Extension of the Kongur Extensional System (KES), Chinese Pamir

NASA Astrophysics Data System (ADS)

Chen, Jie; Schoenbohm, Lindsay M.; Yuan, Zhaode; Li, Wenqiao; Li, Tao; Owen, Lewis A.; Sobel, Edward R.; Hedrick, Kate

2015-04-01

Active deformation in the Chinese Pamir plateau is dominated by east-west extension along the active Kongur extensional system (KES). The KES lies along the northeastern margin of the Pamir at the western end of the Himalayan-Tibetan orogenic belt, and is part of a regional fault system which accommodates east-west extension in the hanging wall of the active Main Pamir Thrust (MPT). Previous work has shown that the MPT has been active since at least the Late Oligocene and accommodates northward motion of the Pamir salient over the Tarim and Tajik basins. It has been proposed that North-directed thrusting along the Main Pamir thrust has been interpreted to be related to east-west extension in the northern Pamir by either extensional collapse of over-thickened crust, or radial thrusting, or oroclinal bending along the Main Pamir Thrust. Alternatively, the east-west extension is related to northward propagation of the right-slip Karakoram fault. A newer model relates the extension to gravitational collapse of the Pamir into the Tadjik depression. Clearly the precise driver remains poorly understood. To better understand the nature of extension in the Pamir and to test the existing models, late Quaternary slip rate along the KES need to be defined using geomorphic mapping, geodetic surveying, Be-10 surface exposure and depth profile dating to quantify rates of fault slip using multiple landforms as strain markers such as offset outwash terraces, lateral moraines, and landslides at five sites, to identify spatial patterns in deformation rates. The preliminary results show that the overall extension direction is subhorizontal, is oriented E-W, and occurs at a high rate of about 7 mm/yr along the Muji and Qimugan faults to the north and deceased to about 1 mm/yr at Kuzigan to the south near Tashkurgan town, which matches the pattern of GPS data. A regional compilation from this study and existing data shows that recent extension along the KES is arc-parallel extension rather than radial thrusting, and is likley related to the collision between the Pamir and Tian Shan along longitude 74.4E and the clockwise rotation of Tarim. The presence of thrust faults (the MPT and Pamir Frontal thrust) in the frontal Pamir and an arc-parallel strike-slip Muji fault farther inboard, as well as normal faults (e.g. the KES) striking perpendicular to the arc, all suggest that strain in the Pamir is partitioned into fairly pure arc-normal shortening and arc-parallel extension and translation along discrete fault systems.

Swinging into Pendulums with a Background.

ERIC Educational Resources Information Center

Barrow, Lloyd H.; Cook, Julie

1993-01-01

Explains reasons why students have misconceptions concerning pendulum swings. Presents a series of 10 pendulum task cards to provide middle-school students with a solid mental scaffolding upon which to build their knowledge of kinetic energy and pendulums. (PR)

How Short and Light Can a Simple Pendulum Be for Classroom Use?

ERIC Educational Resources Information Center

Oliveira, V.

2014-01-01

We compare the period of oscillation of an ideal simple pendulum with the period of a more "real" pendulum constituted of a rigid sphere and a rigid slender rod. We determine the relative error in the calculation of the local acceleration of gravity if the period of the ideal pendulum is used instead of the period of this real pendulum.

How short and light can a simple pendulum be for classroom use?

NASA Astrophysics Data System (ADS)

Oliveira, V.

2014-07-01

We compare the period of oscillation of an ideal simple pendulum with the period of a more ‘real’ pendulum constituted of a rigid sphere and a rigid slender rod. We determine the relative error in the calculation of the local acceleration of gravity if the period of the ideal pendulum is used instead of the period of this real pendulum.

A contribution to calculation of the mathematical pendulum

NASA Astrophysics Data System (ADS)

Anakhaev, K. N.

2014-11-01

In this work, as a continuation of rigorous solutions of the mathematical pendulum theory, calculated dependences were obtained in elementary functions (with construction of plots) for a complete description of the oscillatory motion of the pendulum with determination of its parameters, such as the oscillation period, deviation angles, time of motion, angular velocity and acceleration, and strains in the pendulum rod (maximum, minimum, zero, and gravitational). The results of calculations according to the proposed dependences closely (≪1%) coincide with the exact tabulated data for individual points. The conditions of ascending at which the angular velocity, angular acceleration, and strains in the pendulum rod reach their limiting values equal to and 5 m 1 g, respectively, are shown. It was revealed that the angular acceleration does not depend on the pendulum oscillation amplitude; the pendulum rod strain equal to the gravitation force of the pendulum R s = m 1 g at the time instant is also independent on the amplitude. The dependences presented in this work can also be invoked for describing oscillations of a physical pendulum, mass on a spring, electric circuit, etc.

Complex pendulum biomass sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoskinson, Reed L.; Kenney, Kevin L.; Perrenoud, Ben C.

A complex pendulum system biomass sensor having a plurality of pendulums. The plurality of pendulums allow the system to detect a biomass height and density. Each pendulum has an angular deflection sensor and a deflector at a unique height. The pendulums are passed through the biomass and readings from the angular deflection sensors are fed into a control system. The control system determines whether adjustment of machine settings is appropriate and either displays an output to the operator, or adjusts automatically adjusts the machine settings, such as the speed, at which the pendulums are passed through the biomass. In anmore » alternate embodiment, an entanglement sensor is also passed through the biomass to determine the amount of biomass entanglement. This measure of entanglement is also fed into the control system.« less

The influences of load mass changing on inverted pendulum stability based on simulation study

NASA Astrophysics Data System (ADS)

Pangaribuan, Timbang; Nasruddin, M. N.; Marlianto, Eddy; Sigiro, Mula

2017-09-01

An inverted pendulum has nonlinear dynamic, so it is not easy to do in analysis to see its behavior. From many observations which have been made, there are two things that need to be added on the perfection of inverted pendulum. Firstly, when the pendulum has a large mass, and the second when the pendulum is given a load mass much larger than mass of the inverted pendulum. There are some question, first, how big the load mass can be given so that the movement of the inverted pendulum stay stable is. Second, how weight the changes and moves of load mass which can be given. For all the changes, it hopes the inverted pendulum is stay stable. Finally, the final result is still expected to be as stable, it must need conclude what kind of controller is capable of carrying such a mass burden, and how large the mass load limit can be given.

Seismic structure and stratigraphy of northern edge of Bahaman-Cuban collision zone

USGS Publications Warehouse

Ball, M.M.; Martin, R.G.; Bock, W.D.; Sylwester, R.E.; Bowles, R.M.; Taylor, D.; Coward, E.L.; Dodd, J.E.; Gilbert, L.

1985-01-01

Common-depth-point (CDP) seismic reflection data in the southwestern Bahamas reveal the northern edge of the tectonized zone that resulted from the late Mesozoic-early Cenozoic collision of Cuba and the Bahamas. Two seismic facies are present. A 10-km broad anticline occurs at the south end of Santaren Channel. Platform carbonates in the core of this structure overlie Early Cretaceous and older basinal carbonate deposits and are onlapped by Late Cretaceous and Cenozoic basinal facies. The structure is inferred to be a hanging-wall anticline at the northern limit of the Cuban fold-thrust belt formed in the Late Cretaceous. A deeper water embayment extended northward into the Straits of Florida, around northern Cay Sal Bank, and back into Santaren Channel during the Early Cretaceous.

Experimental Study of Propulsion Performance by Single-Pulse Rotating Detonation with Gaseous Fuels-Oxygen Mixtures

NASA Astrophysics Data System (ADS)

Toshimitsu, Kazuhiko; Hara, Kosei; Mikajiri, Shuuto; Takiguchi, Naoki

2016-12-01

A rotating detonation engine (RDE) is one of candidates of aerospace engines for supersonic cruse, which is better for propulsion system than a pulse detonation engine (PDE) from the view of continuous thrust and simple structure. The propulsion performance of a proto-type RDE and a PDE by single pulse explosion with methane-oxygen is investigated. Furthermore, the performance of the RDE with acetylene-oxygen gas mixtures is investigated. Its impulse is estimated through ballistic pendulum method with maximum displacement and damping ratio. The comparison of specific impulses of the mixture gases at atmospheric pressure is shown. The specific impulses of the RDE and the PDE are almost same with methane-oxygen gas. Furthermore, the fuel-base specific impulse of the RDE with acetylene-oxygen gas is about over twice as large as one of methane-oxygen, and its maximum specific impulse is 1100 seconds.

Vibration analysis of rotor blades with pendulum absorbers

NASA Technical Reports Server (NTRS)

Murthy, V. R.; Hammond, C. E.

1979-01-01

A comprehensive vibration analysis of rotor blades with spherical pendulum absorbers is presented. Linearized equations of motion for small oscillations about the steady-state deflection of a spherical pendulum on elastic rotor blades undergoing coupled flapwise bending, chordwise bending, and torsional vibrations are obtained. A transmission matrix formulation is given to determine the natural vibrational characteristics of rotor blades with spherical or simple flapping pendulum absorbers. The natural frequencies and mode shapes of a hingeless rotor blade with a spherical pendulum are computed.

Lyapunov stability analysis for the generalized Kapitza pendulum

NASA Astrophysics Data System (ADS)

Druzhinina, O. V.; Sevastianov, L. A.; Vasilyev, S. A.; Vasilyeva, D. G.

2017-12-01

In this work generalization of Kapitza pendulum whose suspension point moves in the vertical and horizontal planes is made. Lyapunov stability analysis of the motion for this pendulum subjected to excitation of periodic driving forces and stochastic driving forces that act in the vertical and horizontal planes has been studied. The numerical study of the random motion for generalized Kapitza pendulum under stochastic driving forces has made. It is shown the existence of stable quasi-periodic motion for this pendulum.

Variable shortening on the Main Frontal Thrust in Nepal

NASA Astrophysics Data System (ADS)

Almeida, R. V.; Hubbard, J.; Lee, Y. S.; Liberty, L. M.; Paudel, L.; Shrestha, A.; Sapkota, S. N.; Joshi, G.

2017-12-01

The Main Frontal Thrust (MFT) is the youngest, most active, and southernmost thrust system in the Himalaya. It is located in the footwall of the Main Boundary thrust (MBT), deforming Miocene to Pliocene age Siwalik Group rocks. Although often considered a single, continuous fault, in reality as many as four subparallel faults, spaced 5-30 km apart, make up this fault system. Estimates of total shortening across the MFT for eastern and central Nepal vary from 15 to 40 km, based on cross-sections and surface measurements. However, when the same methods are applied, shortening does not vary significantly along strike (Hirschmiller et al., 2014), suggesting contrasting methodologies rather than a difference in interpreted along strike structural history. Based on high resolution seismic reflection imaging, we present new interpretations of total shortening recorded by the MFT system in central vs. eastern Nepal (200 km apart), together with a detailed transect of field observations in central Nepal. Our structural interpretations demonstrate that the geological shortening recorded on the MFT ranges from >20 km in central Nepal to <1 km in far eastern Nepal. Geodetic measurements show only a slight decrease in interseismic convergence from central (15±1 mm/yr) to eastern Nepal (14±1 mm/yr) and therefore cannot explain this dramatic difference (Lindsey et al., in prep). Taken at face value, these results imply that the MBT must have been much more recently active in eastern Nepal ( 70 ka) than central Nepal ( 1.4 Ma). We propose an alternative model that does not require this dramatic difference in the age of the MFT. As one end-member, it is indeed possible that the MFT may have broken forward much more recently in the east. However, it is also possible that older MFT thrust sheets have formed, and then have been consumed as the MBT passively slid south in the hanging wall of the MFT. Distinguishing between these models is important not only for understanding the evolution of the MBT and MFT, but also plays a critical role in assessing the current geometry and earthquake hazard associated with the Main Himalayan Thrust, the décollement that underlies the entire system (e.g., Hubbard et al., 2016). We explore the implications of these two end-member models and identify ways in which each model could be tested.

New Insight into the Role of Tectonics versus Gravitational Deformation in Development of Surface Ruptures along the Ragged Mountain Fault, Katalla, Alaska USA: Applications of High-Resolution Three-Dimensional Terrain Models

NASA Astrophysics Data System (ADS)

Heinlein, S. N.; Pavlis, T. L.; Bruhn, R. L.; McCalpin, J. P.

2017-12-01

This study evaluates a surface structure using 3D visualization of LiDAR and aerial photography then analyzes these datasets using structure mapping techniques. Results provide new insight into the role of tectonics versus gravitational deformation. The study area is located in southern Alaska in the western edge of the St. Elias Orogen where the Yakutat microplate is colliding into Alaska. Computer applications were used to produce 3D terrain models to create a kinematic assessment of the Ragged Mountain fault which trends along the length of the east flank of Ragged Mountain. The area contains geomorphic and structural features which are utilize to determine the type of displacement on the fault. Previous studies described the Ragged Mountain fault as a very shallow (8°), west-dipping thrust fault that reactivated in the Late Holocene by westward-directed gravity sliding and inferred at least 180 m of normal slip, in a direction opposite to the (relative) eastward thrust transport of the structure inferred from stratigraphic juxtaposition. More recently this gravity sliding hypothesis has been questioned and this study evaluates one of these alternative hypotheses; that uphill facing normal fault-scarps along the Ragged Mountain fault trace represent extension above a buried ramp in a thrust and is evaluated with a fault-parallel flow model of hanging-wall folding and extension. Profiles across the scarp trace were used to illustrate the curvature of the topographic surfaces adjacent to the scarps system and evaluate their origin. This simple kinematic model tests the hypothesis that extensional fault scarps at the surface are produced by flexure above a deeper ramp in a largely blind thrust system. The data in the context of this model implies that the extensional scarp structures previously examined represent a combination of erosionally modified features overprinted by flexural extension above a thrust system. Analyses of scarp heights along the structure are combined with the model to suggest a decrease in Holocene slip from south to north along the Ragged Mountain fault from 11.3 m to 0.2 m, respectively.

Effects induced by an earthquake on its fault plane:a boundary element study

NASA Astrophysics Data System (ADS)

Bonafede, Maurizio; Neri, Andrea

2000-04-01

Mechanical effects left by a model earthquake on its fault plane, in the post-seismic phase, are investigated employing the `displacement discontinuity method'. Simple crack models, characterized by the release of a constant, unidirectional shear traction are investigated first. Both slip components-parallel and normal to the traction direction-are found to be non-vanishing and to depend on fault depth, dip, aspect ratio and fault plane geometry. The rake of the slip vector is similarly found to depend on depth and dip. The fault plane is found to suffer some small rotation and bending, which may be responsible for the indentation of a transform tectonic margin, particularly if cumulative effects are considered. Very significant normal stress components are left over the shallow portion of the fault surface after an earthquake: these are tensile for thrust faults, compressive for normal faults and are typically comparable in size to the stress drop. These normal stresses can easily be computed for more realistic seismic source models, in which a variable slip is assigned; normal stresses are induced in these cases too, and positive shear stresses may even be induced on the fault plane in regions of high slip gradient. Several observations can be explained from the present model: low-dip thrust faults and high-dip normal faults are found to be facilitated, according to the Coulomb failure criterion, in repetitive earthquake cycles; the shape of dip-slip faults near the surface is predicted to be upward-concave; and the shallower aftershock activity generally found in the hanging block of a thrust event can be explained by `unclamping' mechanisms.

Quantifying Quaternary Deformation in the Eastern Cordillera of the Colombian Andes Using Cosmogenic Nuclide Geochronology and Fluvial Geomorphology

NASA Astrophysics Data System (ADS)

Dalman, E.; Taylor, M. H.; Veloza-fajardo, G.; Mora, A.

2014-12-01

Northwest South America is actively deforming through the interaction between the Nazca, South American, and Caribbean plates. Though the Colombian Andes are well studied, much uncertainty remains in the rate of Quaternary deformation along the east directed frontal thrust faults hundreds of kilometers in board from the subduction zones. The eastern foothills of the Eastern Cordillera (EC) preserve deformed landforms, allowing us to quantify incision rates. Using 10Be in-situ terrestrial cosmogenic nuclide (TCN) geochronology, we dated 2 deformed fluvial terraces in the hanging wall of the Guaicaramo thrust fault. From the 10Be concentration and terrace profile relative to local base level, we calculated incision rates. We present a reconstructed slip history of the Guaicaramo thrust fault and its Quaternary slip rate. Furthermore, to quantify the regional Quaternary deformation, we look at the fluvial response to tectonic uplift. Approximately 20 streams along the eastern foothills of the Eastern Cordillera (EC) were studied using a digital elevation model (DEM). From the DEM, longitudinal profiles were created and normalized channel steepness (Ksn) values calculated from plots of drainage area vs. slope. Knickpoints in the longitudinal profiles can record transient perturbations or differential uplift. Calculated Ksn values indicate that the EC is experiencing high rates of uplift, with the highest mean Ksn values occurring in the Cocuy region. Mean channel steepness values along strike of the foothills are related to increasing uplift rates from south to north. In contrast, we suggest that high channel steepness values in the south appear to be controlled by high rates of annual precipitation.

Stabilization and tracking control of X-Z inverted pendulum with sliding-mode control.

PubMed

Wang, Jia-Jun

2012-11-01

X-Z inverted pendulum is a new kind of inverted pendulum which can move with the combination of the vertical and horizontal forces. Through a new transformation, the X-Z inverted pendulum is decomposed into three simple models. Based on the simple models, sliding-mode control is applied to stabilization and tracking control of the inverted pendulum. The performance of the sliding mode control is compared with that of the PID control. Simulation results show that the design scheme of sliding-mode control is effective for the stabilization and tracking control of the X-Z inverted pendulum. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Towards the miniaturization of monolithic folded pendulums: a new approach to the implementation of small and light sensors for ground, space, and marine applications

NASA Astrophysics Data System (ADS)

Barone, F.; Giordano, G.

2018-03-01

The UNISA Folded Pendulum technological platform is very promising for the implementation of high sensitive, large band miniaturized mechanical seismometers and accelerometers in different materials. In fact, the symmetry of its mechanical architecture allows to take full advantage of one of the most relevant properties of the folded pendulum, that is the scalability. This property is very useful for the design of folded pendulums of small size and weight, provided with a suitable combination of physical and geometrical parameters. Using a lagrangian simplified model of folded pendulum, we present and discuss this idea, showing different possible approaches that may lead to the miniaturization of a folded pendulum. Finally we present a first prototype of miniaturized folded pendulum, discussing its characteristics and limitations, in connection with scientific ground, marine and space applications.

Pendulums in the Physics Education Literature: A Bibliography

ERIC Educational Resources Information Center

Gauld, Colin

2004-01-01

Articles about the pendulum in four journals devoted to the teaching of physics and one general science teaching journal (along with other miscellaneous articles from other journals) are listed in three broad categories--types of pendulums, the contexts in which these pendulums are used in physics teaching at secondary or tertiary levels and a…

Introduction to the Treatment of Non-Linear Effects Using a Gravitational Pendulum

ERIC Educational Resources Information Center

Weltner, Klaus; Esperidiao, Antonio Sergio C.; Miranda, Paulo

2004-01-01

We show that the treatment of pendulum movement, other than the linear approximation,may be an instructive experimentally based introduction to the physics of non-linear effects. Firstly the natural frequency of a gravitational pendulum is measured as function of its amplitude. Secondly forced oscillations of a gravitational pendulum are…

Paleoseismology of the Chelungpu Fault during the past 1900 years

USGS Publications Warehouse

Chen, W.-S.; Lee, K.-J.; Lee, L.-S.; Ponti, D.J.; Prentice, C.; Chen, Y.-G.; Chang, H.-C.; Lee, Y.-H.

2003-01-01

The 1999 earthquake brought about 80-km-long surface ruptures along the Shihkang, Chelungpu, and Tajienshan Faults, central Taiwan. Several trenches have been excavated across the Chelungpu Fault of the middle segment. The surface ruptures display clear scarps ranging from 0.2 to 4 m high, showing a complex geomorphic pattern due to coseismic faulting and folding. In the study, measurement of the vertical offset or structural relief was taken with reference to the hanging wall beyond the trishear deformation zone. Therefore we suggest that, for the measurement of offset, we should disregard the trishear zone, and that structural relief on the hanging wall should be represented as a real vertical offset. The net slip is then calculated from the structural relief and dip angle of the thrust on a vertical plane along the slip direction. Through the excavation of a pineapple field across the Chelungpu Fault, we are able to provide evidence of at least four earthquake events for the past about 1900 years, including the 1999 earthquake. Furthermore, based on the radiocarbon dates and historical record, the timing of the penultimate event is bracketed to be between 430 and 150 years ago, and the average recurrence interval is less than 700 years. These data indicate that the average slip rate is about 8.7 mm/yr for the past 1900 years. ?? 2003 Published by Elsevier Ltd.

Pendulum and modified pendulum appliances for maxillary molar distalization in Class II malocclusion - a systematic review.

PubMed

Al-Thomali, Yousef; Basha, Sakeenabi; Mohamed, Roshan Noor

2017-08-01

The main purpose of the present systematic review was to evaluate the quantitative effects of the pendulum appliance and modified pendulum appliances for maxillary molar distalization in Class II malocclusion. Our systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus and key journals and review articles; the date of the last search was 30 January 2017. We graded the methodological quality of the studies by means of the Quality Assessment Tool for Quantitative Studies, developed for the Effective Public Health Practice Project (EPHPP). In total, 203 studies were identified for screening, and 25 studies were eligible. The quality assessment rated four (16%) of the study as being of strong quality and 21 (84%) of these studies as being of moderate quality. The pendulum appliances showed mean molar distalization of 2-6.4 mm, distal tipping of molars from 6.67° to 14.50° and anchorage loss with mean premolar and incisor mesial movement of 1.63-3.6 mm and 0.9-6.5 mm, respectively. The bone anchored pendulum appliances (BAPAs) showed mean molar distalization of 4.8-6.4 mm, distal tipping of molars from 9° to 11.3° and mean premolar distalization of 2.7-5.4 mm. Pendulum and modified pendulum appliances are effective in molar distalization. Pendulum appliance with K-loop modification, implant supported pendulum appliance and BAPA significantly reduced anchorage loss of the anterior teeth and distal tipping of the molar teeth.

Experimental Investigation of Axial and Beam-Riding Propulsive Physics with TEA CO{sub 2} laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kenoyer, D. A.; Salvador, I.; Myrabo, L. N.

2010-10-08

A twin Lumonics K922M pulsed TEA CO{sub 2} laser system (pulse duration of approximately 100 ns FWHM spike, with optional 1 {mu}s tail, depending upon laser gas mix) was employed to experimentally measure both axial thrust and beam-riding behavior of Type no. 200 lightcraft engines, using a ballistic pendulum and Angular Impulse Measurement Device (AIMD, respectively. Beam-riding forces and moments were examined along with engine thrust-vectoring behavior, as a function of: a) laser beam lateral offset from the vehicle axis of symmetry; b) laser pulse energy ({approx}12 to 40 joules); c) pulse duration (100 ns, and 1 {mu}s); and d)more » engine size (97.7 mm to 161.2 mm). Maximum lateral momentum coupling coefficients (C{sub M}) of 75 N-s/MJ were achieved with the K922M laser whereas previous PLVTS laser (420 J, 18 {mu}s duration) results reached only 15 N-s/MJ--an improvement of 5x. Maximum axial C{sub M} performance with the K922M reached 225 N-s/MJ, or about {approx}3x larger than the lateral C{sub M} values. These axial C{sub M} results are sharply higher than the 120 N/MW previously reported for long pulse (e.g., 10-18 {mu}s)CO{sub 2} electric discharge lasers.« less

Inverted temperature sequences: role of deformation partitioning

NASA Astrophysics Data System (ADS)

Grujic, D.; Ashley, K. T.; Coble, M. A.; Coutand, I.; Kellett, D.; Whynot, N.

2015-12-01

The inverted metamorphism associated with the Main Central thrust zone in the Himalaya has been historically attributed to a number of tectonic processes. Here we show that there is actually a composite peak and deformation temperature sequence that formed in succession via different tectonic processes. The deformation partitioning seems to the have played a key role, and the magnitude of each process has varied along strike of the orogen. To explain the formation of the inverted metamorphic sequence across the Lesser Himalayan Sequence (LHS) in eastern Bhutan, we used Raman spectroscopy of carbonaceous material (RSCM) to determine the peak metamorphic temperatures and Ti-in-quartz thermobarometry to determine the deformation temperatures combined with thermochronology including published apatite and zircon U-Th/He and fission-track data and new 40Ar/39Ar dating of muscovite. The dataset was inverted using 3D-thermal-kinematic modeling to constrain the ranges of geological parameters such as fault geometry and slip rates, location and rates of localized basal accretion, and thermal properties of the crust. RSCM results indicate that there are two peak temperature sequences separated by a major thrust within the LHS. The internal temperature sequence shows an inverted peak temperature gradient of 12 °C/km; in the external (southern) sequence, the peak temperatures are constant across the structural sequence. Thermo-kinematic modeling suggest that the thermochronologic and thermobarometric data are compatible with a two-stage scenario: an Early-Middle Miocene phase of fast overthrusting of a hot hanging wall over a downgoing footwall and inversion of the synkinematic isotherms, followed by the formation of the external duplex developed by dominant underthrusting and basal accretion. To reconcile our observations with the experimental data, we suggest that pervasive ductile deformation within the upper LHS and along the Main Central thrust zone at its top stopped at ~11 Ma at which time the deformation shifted and focused within the external duplex and the Main Boundary Thrust.

49 CFR 572.193 - Neck assembly.

Code of Federal Regulations, 2014 CFR

2014-10-01

... or V2-B in appendix A to this subpart, to the 49 CFR Part 572 pendulum test fixture (Figure 22, 49... motion of the pendulum longitudinal centerline; (3) Release the pendulum from a height sufficient to achieve a velocity of 5.57 ±0.06 m/s measured at the center of the pendulum accelerometer, as shown in 49...

49 CFR 572.73 - Neck assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... rotate, while translating in the direction of the pendulum preimpact flight, in reference to the pendulum... displacement at time “T” is defined as the straight line distance between the position relative to the pendulum arm of the head's center of gravity at time “zero;” and the position relative to the pendulum arm of...

49 CFR 572.193 - Neck assembly.

Code of Federal Regulations, 2012 CFR

2012-10-01

... or V2-B in appendix A to this subpart, to the 49 CFR Part 572 pendulum test fixture (Figure 22, 49... motion of the pendulum longitudinal centerline; (3) Release the pendulum from a height sufficient to achieve a velocity of 5.57 ±0.06 m/s measured at the center of the pendulum accelerometer, as shown in 49...

49 CFR 572.73 - Neck assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... rotate, while translating in the direction of the pendulum preimpact flight, in reference to the pendulum... displacement at time “T” is defined as the straight line distance between the position relative to the pendulum arm of the head's center of gravity at time “zero;” and the position relative to the pendulum arm of...

A Simple Method to Measure the Trajectory of a Spherical Pendulum

ERIC Educational Resources Information Center

Yang, Hujiang; Xiao, Jinghua; Yang, Tianyu; Qiu, Chen

2011-01-01

Compared with a single gravity pendulum, the spherical pendulum behaves more complicatedly in experiments, which makes it difficult to measure. In this paper, we present a method to visualize the trajectories of a spherical pendulum by employing a gravity ball with a lit LED and a digital camera. This new measurement is inexpensive and easy to…

49 CFR 572.193 - Neck assembly.

Code of Federal Regulations, 2013 CFR

2013-10-01

... or V2-B in appendix A to this subpart, to the 49 CFR Part 572 pendulum test fixture (Figure 22, 49... motion of the pendulum longitudinal centerline; (3) Release the pendulum from a height sufficient to achieve a velocity of 5.57 ±0.06 m/s measured at the center of the pendulum accelerometer, as shown in 49...

49 CFR 572.193 - Neck assembly.

Code of Federal Regulations, 2011 CFR

2011-10-01

... or V2-B in appendix A to this subpart, to the 49 CFR Part 572 pendulum test fixture (Figure 22, 49... of motion of the pendulum longitudinal centerline; (3) Release the pendulum from a height sufficient to achieve a velocity of 5.57 ± 0.06 m/s measured at the center of the pendulum accelerometer, as...

49 CFR 572.73 - Neck assembly and test procedure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... rotate, while translating in the direction of the pendulum preimpact flight, in reference to the pendulum... displacement at time “T” is defined as the straight line distance between the position relative to the pendulum arm of the head's center of gravity at time “zero;” and the position relative to the pendulum arm of...

Turning Points of the Spherical Pendulum and the Golden Ratio

ERIC Educational Resources Information Center

Essen, Hanno; Apazidis, Nicholas

2009-01-01

We study the turning point problem of a spherical pendulum. The special cases of the simple pendulum and the conical pendulum are noted. For simple initial conditions the solution to this problem involves the golden ratio, also called the golden section, or the golden number. This number often appears in mathematics where you least expect it. To…

49 CFR 572.73 - Neck assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... rotate, while translating in the direction of the pendulum preimpact flight, in reference to the pendulum... displacement at time “T” is defined as the straight line distance between the position relative to the pendulum arm of the head's center of gravity at time “zero;” and the position relative to the pendulum arm of...

49 CFR 572.193 - Neck assembly.

Code of Federal Regulations, 2010 CFR

2010-10-01

... or V2-B in appendix A to this subpart, to the 49 CFR Part 572 pendulum test fixture (Figure 22, 49... of motion of the pendulum longitudinal centerline; (3) Release the pendulum from a height sufficient to achieve a velocity of 5.57 ± 0.06 m/s measured at the center of the pendulum accelerometer, as...

49 CFR 572.73 - Neck assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... rotate, while translating in the direction of the pendulum preimpact flight, in reference to the pendulum... displacement at time “T” is defined as the straight line distance between the position relative to the pendulum arm of the head's center of gravity at time “zero;” and the position relative to the pendulum arm of...

Inverting the Pendulum Using Fuzzy Control (Center Director's Discretionary Fund (Project 93-02)

NASA Technical Reports Server (NTRS)

Kissel, R. R.; Sutherland, W. T.

1997-01-01

A single pendulum was simulated in software and then built on a rotary base. A fuzzy controller was used to show its advantages as a nonlinear controller since bringing the pendulum inverted is extremely nonlinear. The controller was implemented in a Motorola 6811 microcontroller. A double pendulum was simulated and fuzzy control was used to hold it in a vertical position. The double pendulum was not built into hardware for lack of time. This project was for training and to show advantages of fuzzy control.

Coseismic fault zone deformation caused by the 2014 Mw=6.2 Nagano-ken-hokubu, Japan, earthquake on the Itoigawa-Shizuoka Tectonic Line revealed with differential LiDAR

NASA Astrophysics Data System (ADS)

Toda, S.; Ishimura, D.; Homma, S.; Mukoyama, S.; Niwa, Y.

2015-12-01

The Mw = 6.2 Nagano-ken-hokubu earthquake struck northern Nagano, central Japan, on November 22, 2014, and accompanied a 9-km-long surface rupture mostly along the previously mapped N-NW trending Kamishiro fault, one of the segments of the 150-km-long Itoigawa-Shizuoka Tectonic Line active fault system. While we mapped the rupture and measured vertical displacement of up to 80 cm at the field, interferometric synthetic aperture radar (InSAR) shows densely spaced fringes on the hanging wall side, suggesting westward or uplift movement associated with thrust faulting. The mainshock focal mechanism and aftershock hypocenters indicate the source fault dips to the east but the InSAR images cannot exactly differentiate between horizontal and vertical movements and also lose coherence within and near the fault zone itself. To reveal near-field deformation and shallow fault slip, here we demonstrate a differential LiDAR analysis using a pair of 1 m-resolution pre-event and post-event bare Earth digital terrain models (DTMs) obtained from commercial LiDAR provider. We applied particle image velocity (PIV) method incorporating elevation change to obtain 3-D vectors of coseismic displacements (Mukoyama, 2011, J. Mt. Sci). Despite sporadic noises mostly due to local landslides, we detected up to 1.5 m net movement at the tip of the hanging wall, more than the field measurement of 80 cm. Our result implies that a 9-km-long rupture zone is not a single continuous fault but composed of two bow-shaped fault strands, suggesting a combination of shallow fault dip and modest amount (< 1.5 m) of slip. Eastward movement without notable subsidence on the footwall also supports the low angle fault dip near the surface, and significant fault normal contraction, observed as buckled cultural features across the fault zone. Secondary features, such as subsidiary back-thrust faults confirmed at the field, are also visible as a significant contrast of vector directions and slip amounts.

Paleothermal structure of the Nankai inner accretionary wedge estimated from vitrinite reflectance of cuttings

NASA Astrophysics Data System (ADS)

Fukuchi, Rina; Yamaguchi, Asuka; Yamamoto, Yuzuru; Ashi, Juichiro

2017-08-01

The paleothermal structure and tectonic evolution of an accretionary prism is basic information for understanding subduction zone seismogenesis. To evaluate the entire paleotemperature profile of the Integrated Ocean Drilling Program (IODP) Site C0002 located in the off-Kumano region of the Nankai Trough and penetrate the inner accretionary wedge down to 3058.5 m below the seafloor (mbsf), we performed a vitrinite reflectance analysis for cuttings and core samples during IODP expeditions 338 and 348: Nankai Trough seismogenic zone experiment. Although vitrinite reflectance values (Ro) tend to increase with depth, two reversals of these values suggested the existence of thrust fault zones with sufficient displacements to offset the paleothermal structure. The estimated maximum paleotemperatures are 42-70°C at 1200-1300 mbsf, 44-100°C at 1600-2400 mbsf, and 56-115°C at 2600-3000 mbsf, respectively. These temperatures roughly coincide with estimated modern temperatures; however, at a smaller scale, the reconstructed partial paleogeothermal gradient (˜60-150°C/km) recorded at the hanging- and footwall of the presumed thrust fault zone is higher than the modern geothermal gradient (˜30-40°C/km). This high paleogeothermal gradient was possibly obtained prior to subduction, reflecting the large heat flow of the young Philippine Sea Plate.

Intelligent clutch control with incremental encoder to improve wear issues of an intercept pendulum in real time

NASA Astrophysics Data System (ADS)

Jalba, C. K.; Diekmann, R.; Epple, S.

2017-01-01

A pendulum impact tester is a technical device which is used to perform plasticity characterizations of metallic materials. Results are calculated based on fracture behavior under pendulum impact loadings according to DIN 50115, DIN 51222/EN 10045. The material is held at the two ends and gets struck in the middle. A mechanical Problem occurs when testing materials with a very high impact toughness. These specimen often do not break when hit by the pendulum. To return the pendulum to its initial position, the operator presses a service button. After a delay of approximately 2 seconds a clutch is activated which connects the arm of the pendulum with an electric motor to return it back upright in start position. At the moment of clutch activation, the pendulum can still swing or bounce with any speed in any direction at any different position. Due to the lack of synchronization between pendulum speed and constant engine speed, the clutch suffers heavy wear of friction. This disadvantage results in considerable service and repair costs for the customer. As a solution to this problem this article presents a customized technical device to significantly increase the lifetime of the clutch. It was accomplished by a precisely controlled activation of the clutch at a point of time when pendulum and motor are at synchronized speed and direction using incremental encoders.

Roles of Abductive Reasoning and Prior Belief in Children's Generation of Hypotheses about Pendulum Motion

ERIC Educational Resources Information Center

Kwon, Yong-Ju; Jeong, Jin-Su; Park, Yun-Bok

2006-01-01

The purpose of the present study was to test the hypothesis that student's abductive reasoning skills play an important role in the generation of hypotheses on pendulum motion tasks. To test the hypothesis, a hypothesis-generating test on pendulum motion, and a prior-belief test about pendulum motion were developed and administered to a sample of…

Foot trajectory approximation using the pendulum model of walking.

PubMed

Fang, Juan; Vuckovic, Aleksandra; Galen, Sujay; Conway, Bernard A; Hunt, Kenneth J

2014-01-01

Generating a natural foot trajectory is an important objective in robotic systems for rehabilitation of walking. Human walking has pendular properties, so the pendulum model of walking has been used in bipedal robots which produce rhythmic gait patterns. Whether natural foot trajectories can be produced by the pendulum model needs to be addressed as a first step towards applying the pendulum concept in gait orthosis design. This study investigated circle approximation of the foot trajectories, with focus on the geometry of the pendulum model of walking. Three able-bodied subjects walked overground at various speeds, and foot trajectories relative to the hip were analysed. Four circle approximation approaches were developed, and best-fit circle algorithms were derived to fit the trajectories of the ankle, heel and toe. The study confirmed that the ankle and heel trajectories during stance and the toe trajectory in both the stance and the swing phases during walking at various speeds could be well modelled by a rigid pendulum. All the pendulum models were centred around the hip with pendular lengths approximately equal to the segment distances from the hip. This observation provides a new approach for using the pendulum model of walking in gait orthosis design.

Radial forcing and Edgar Allan Poe's lengthening pendulum

NASA Astrophysics Data System (ADS)

McMillan, Matthew; Blasing, David; Whitney, Heather M.

2013-09-01

Inspired by Edgar Allan Poe's The Pit and the Pendulum, we investigate a radially driven, lengthening pendulum. We first show that increasing the length of an undriven pendulum at a uniform rate does not amplify the oscillations in a manner consistent with the behavior of the scythe in Poe's story. We discuss parametric amplification and the transfer of energy (through the parameter of the pendulum's length) to the oscillating part of the system. In this manner, radial driving can easily and intuitively be understood, and the fundamental concept applied in many other areas. We propose and show by a numerical model that appropriately timed radial forcing can increase the oscillation amplitude in a manner consistent with Poe's story. Our analysis contributes a computational exploration of the complex harmonic motion that can result from radially driving a pendulum and sheds light on a mechanism by which oscillations can be amplified parametrically. These insights should prove especially valuable in the undergraduate physics classroom, where investigations into pendulums and oscillations are commonplace.

A Study for the Restoration of Hong Dae-Yong Honsangui - Focusing on the structure and operating mechanism

NASA Astrophysics Data System (ADS)

Lee, Yong Sam; Kim, Sang Hyuk; Park, Je Hoon

2013-09-01

Honsangui (celestial globe) which is a water-hammering method astronomical clock is recorded in "Juhaesuyong" which is Volume VI of supplement from "Damheonseo", written by Hong Dae-Yong (1731~1783). We made out the conceptual design of Hong Dae-Yong's Honsangui through the study on its structure and working mechanism. Honsangui consist of three rings and two layers, the structure of rings which correspond to outer layer is similar to his own Tongcheonui (armillary sphere) which is a kind of armillary sphere. Honsang sphere which correspond to inner layer depicts constellations and milky way and two beads hang on it as Sun and Moon respectively for realize the celestial motion. Tongcheonui is operated by the pendulum power but Honsangui is operated by water-hammering method mechanism. This Honsangui's working mechanism is the traditional way of Joseon and it was simplified the working mechanism of Shui y'n i hsiang t'ai which is a representative astronomical clock of China. This record of Honsangui is the only historical record about the water-hammering method working mechanism of Joseon Era and it provide the study of water-hammering method mechanism with a vital clue.

Desktop chaotic systems: Intuition and visualization

NASA Technical Reports Server (NTRS)

Bright, Michelle M.; Melcher, Kevin J.; Qammar, Helen K.; Hartley, Tom T.

1993-01-01

This paper presents a dynamic study of the Wildwood Pendulum, a commercially available desktop system which exhibits a strange attractor. The purpose of studying this chaotic pendulum is twofold: to gain insight in the paradigmatic approach of modeling, simulating, and determining chaos in nonlinear systems; and to provide a desktop model of chaos as a visual tool. For this study, the nonlinear behavior of this chaotic pendulum is modeled, a computer simulation is performed, and an experimental performance is measured. An assessment of the pendulum in the phase plane shows the strange attractor. Through the use of a box-assisted correlation dimension methodology, the attractor dimension is determined for both the model and the experimental pendulum systems. Correlation dimension results indicate that the pendulum and the model are chaotic and their fractal dimensions are similar.

The Pendulum as a Vehicle for Transitioning from Classical to Quantum Physics: History, Quantum Concepts, and Educational Challenges

ERIC Educational Resources Information Center

Barnes, Marianne B.; Garner, James; Reid, David

2004-01-01

In this article we use the pendulum as the vehicle for discussing the transition from classical to quantum physics. Since student knowledge of the classical pendulum can be generalized to all harmonic oscillators, we propose that a quantum analysis of the pendulum can lead students into the unanticipated consequences of quantum phenomena at the…

Segmented Hoop as a Physical Pendulum

ERIC Educational Resources Information Center

Layton, William; Rodriguez, Nuria

2013-01-01

An interesting demonstration with a surprising result is to suspend a hoop from a point near its edge and set it swinging in a vertical plane as a pendulum. If a simple pendulum of length equal to the diameter of the hoop is set oscillating at the same time, the two will have nearly the same period. However, the real surprise is if the pendulum is…

A Novel Real-Time Data Acquisition Using an Excel Spreadsheet in Pendulum Experiment Tool with Light-Based Timer

ERIC Educational Resources Information Center

Adhitama, Egy; Fauzi, Ahmad

2018-01-01

In this study, a pendulum experimental tool with a light-based timer has been developed to measure the period of a simple pendulum. The obtained data was automatically recorded in an Excel spreadsheet. The intensity of monochromatic light, sensed by a 3DU5C phototransistor, dynamically changes as the pendulum swings. The changed intensity varies…

Dynamic stabilization of an optomechanical oscillator

DTIC Science & Technology

2014-10-20

respectively. The proper frequency of the pendulum is ω0 = √ g/, where g is the gravitational acceleration and is the length of the pendulum . The...controlled experiments. In this paper we discuss one such situation, the dynamic stabilization of a mechanical system such as an inverted pendulum . The...quantumoptomechanics, macroscopic quantum system, dynamic stabilization, Kapitza pendulum REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S

Ask the pendulum: personality predictors of ideomotor performance.

PubMed

Olson, Jay A; Jeyanesan, Ewalina; Raz, Amir

2017-01-01

For centuries, people have asked questions to hand-held pendulums and interpreted their movements as responses from the divine. These movements occur due to the ideomotor effect, wherein priming or thinking of a motion causes muscle movements that end up swinging the pendulum. By associating particular swinging movements with "yes" and "no" responses, we investigated whether pendulums can aid decision-making and which personality traits correlate with this performance. Participants ( N = 80 ) completed a visual detection task in which they searched for a target letter among rapidly presented characters. In the verbal condition, participants stated whether they saw the target in each trial. In the pendulum condition, participants instead mentally "asked" a hand-held pendulum whether the target was present; particular motions signified "yes" and "no". We measured the accuracy of their responses as well as their sensitivity and bias using signal detection theory. We also assessed four personality measures: locus of control (feelings of control over one's life), transliminality (sensitivity to subtle stimuli), need for cognition (preference for analytical thinking), and faith in intuition (preference for intuitive thinking). Overall, locus of control predicted verbal performance and transliminality predicted pendulum performance. Accuracy was low in both conditions (verbal: 57%, pendulum: 53%), but bias was higher in the verbal condition ( d = 1.10 ). We confirmed this bias difference in a second study ( d = 0.47 , N = 40 ). Our results suggest that people have different decision strategies when using a pendulum compared to conscious guessing. These findings may help explain why some people can answer questions more accurately with pendulums and Ouija boards. More broadly, identifying the differences between ideomotor and verbal responses could lead to practical ways to improve decision-making.

Ask the pendulum: personality predictors of ideomotor performance

PubMed Central

Olson, Jay A; Jeyanesan, Ewalina; Raz, Amir

2017-01-01

Abstract For centuries, people have asked questions to hand-held pendulums and interpreted their movements as responses from the divine. These movements occur due to the ideomotor effect, wherein priming or thinking of a motion causes muscle movements that end up swinging the pendulum. By associating particular swinging movements with “yes” and “no” responses, we investigated whether pendulums can aid decision-making and which personality traits correlate with this performance. Participants (N=80) completed a visual detection task in which they searched for a target letter among rapidly presented characters. In the verbal condition, participants stated whether they saw the target in each trial. In the pendulum condition, participants instead mentally “asked” a hand-held pendulum whether the target was present; particular motions signified “yes” and “no”. We measured the accuracy of their responses as well as their sensitivity and bias using signal detection theory. We also assessed four personality measures: locus of control (feelings of control over one’s life), transliminality (sensitivity to subtle stimuli), need for cognition (preference for analytical thinking), and faith in intuition (preference for intuitive thinking). Overall, locus of control predicted verbal performance and transliminality predicted pendulum performance. Accuracy was low in both conditions (verbal: 57%, pendulum: 53%), but bias was higher in the verbal condition (d=1.10). We confirmed this bias difference in a second study (d=0.47, N=40). Our results suggest that people have different decision strategies when using a pendulum compared to conscious guessing. These findings may help explain why some people can answer questions more accurately with pendulums and Ouija boards. More broadly, identifying the differences between ideomotor and verbal responses could lead to practical ways to improve decision-making. PMID:29877514

A biomechanical model of the craniomandibular complex and cervical spine based on the inverted pendulum.

PubMed

Gillies, G T; Broaddus, W C; Stenger, J M; Taylor, A G

1998-01-01

The head and neck constitute an inverted pendulum that is stabilized during consciousness by neuromuscular restoring forces. An analysis of the dynamics of this inverted pendulum suggests that the mechanics of the mandible and temporomandibular joint might couple into those of the pendulum's stabilization process. In this article, physical principles of the inverted pendulum model as these apply to the head and neck are explored, and the authors describe implications of mandibular mechanics for the forces acting on the head and neck at equilibrium. This novel application of the inverted pendulum model predicts that alteration or pathology of temporomandibular mechanics would lead to perturbations of the normal forces acting in the head and neck. Under certain circumstances, these perturbations could be expected to contribute to symptoms and result in additional or accelerated degenerative effects.

Charge management for gravitational-wave observatories using UV LEDs

NASA Astrophysics Data System (ADS)

Pollack, S. E.; Turner, M. D.; Schlamminger, S.; Hagedorn, C. A.; Gundlach, J. H.

2010-01-01

Accumulation of electrical charge on the end mirrors of gravitational-wave observatories can become a source of noise limiting the sensitivity of such detectors through electronic couplings to nearby surfaces. Torsion balances provide an ideal means for testing gravitational-wave technologies due to their high sensitivity to small forces. Our torsion pendulum apparatus consists of a movable plate brought near a plate pendulum suspended from a nonconducting quartz fiber. A UV LED located near the pendulum photoejects electrons from the surface, and a UV LED driven electron gun directs photoelectrons towards the pendulum surface. We have demonstrated both charging and discharging of the pendulum with equivalent charging rates of ˜105e/s, as well as spectral measurements of the pendulum charge resulting in a white noise level equivalent to 3×105e/Hz.

Energy behavior of an electromechanical system with internal impacts and uncertainties

NASA Astrophysics Data System (ADS)

Lima, Roberta; Sampaio, Rubens

2016-07-01

This paper analyzes the maximal energy stored in an elastic barrier due to the impacts of a pendulum fitted within a vibro-impact electromechanical system considering the existence of epistemic uncertainties in the system parameters. The vibro-impact electromechanical system is composed of two subsystems. The first subsystem is the electromechanical system composed by a motor, cart and pendulum, and the second is an elastic barrier. The first will be called striker system. The pendulum is fitted within the cart. Its suspension point is fixed in the cart, so that it may exist a relative motion between cart and pendulum. The influence of the DC motor in the dynamic behavior of the pendulum is considered. The coupling between the motor and the cart is made by a scotch yoke mechanism, so that the motor rotational motion is transformed in horizontal cart motion over a rail. The pendulum is modeled as a mathematical pendulum (bar without mass and particle of mass mp at the end). A flexible barrier, placed inside the cart, constrains the pendulum motion. Due to the relative motion between the cart and the pendulum, impacts may occur between these two elements. The objective of the paper is to analyze the energy stored in the barrier due to impacts as a function of some parameters of the electromechanical system from a deterministic and from a stochastic viewpoint. The system is designed as an aid in drilling. The impacts damage or fracture the rock and facilitate the conventional drilling.

Response of pendulums to complex input ground motion

USGS Publications Warehouse

Graizer, V.; Kalkan, E.

2008-01-01

Dynamic response of most seismological instruments and many engineering structures to ground shaking can be represented via response of a pendulum (single-degree-of-freedom oscillator). In most studies, pendulum response is simplified by considering the input from uni-axial translational motion alone. Complete ground motion however, includes not only translational components but also rotations (tilt and torsion). In this paper, complete equations of motion for three following types of pendulum are described: (i) conventional (mass-on-rod), (ii) mass-on-spring type, and (iii) inverted (astatic), then their response sensitivities to each component of complex ground motion are examined. The results of this study show that a horizontal pendulum similar to an accelerometer used in strong motion measurements is practically sensitive to translational motion and tilt only, while inverted pendulum commonly utilized to idealize multi-degree-of-freedom systems is sensitive not only to translational components, but also to angular accelerations and tilt. For better understanding of the inverted pendulum's dynamic behavior under complex ground excitation, relative contribution of each component of motion on response variants is carefully isolated. The systematically applied loading protocols indicate that vertical component of motion may create time-dependent variations on pendulum's oscillation period; yet most dramatic impact on response is produced by the tilting (rocking) component. ?? 2007 Elsevier Ltd. All rights reserved.

Assessment of energy harvesting and vibration mitigation of a pendulum dynamic absorber

NASA Astrophysics Data System (ADS)

Kecik, Krzysztof

2018-06-01

The paper presents a novel system for simultaneous energy harvesting and vibration mitigation. The system consists of two main parts: an autoparametric pendulum vibration absorber and an energy harvester device. The recovered energy is from oscillation of a levitating magnet in a coil. The energy harvesting system is mounted in a pendulum structure. The system allows energy recovery from a semi-trivial solution (pendulum in rest) or/and swinging of a pendulum. The influence of harvester parameters on the system response and energy harvesting in a parametric resonance is studied in detail. The harvester device does not decrease vibration reduction effectiveness.

Measure synchronization in a Huygens's non-dissipative two-pendulum clocks system

NASA Astrophysics Data System (ADS)

Tian, Jing; Chen, ZiChen; Qiu, HaiBo; Xi, XiaoQiang

2018-01-01

In this paper, we characterize measure synchronization (MS) in a four-degrees-of-freedom Huygens's two-pendulum clocks system. The two-pendulum clocks are connected by a massless spring with stiffness constant k. We find that with the stiffness constant k increasing, the coupled pendulums system achieves MS above a threshold value of k c . The energy characteristics of measure synchronization have been discussed, it is found that averaged energy of each pendulum system provide us an easy way to characterize MS transition. Furthermore, we discuss the dependence of the critical value for MS transition on initial conditions and the characteristic parameters of the system.

Shoulder Injuries and Disorders - Multiple Languages

MedlinePlus

... Af-Soomaali (Somali) Bilingual PDF Health Information Translations Pendulum Exercises for Shoulder - Af-Soomaali (Somali) Bilingual PDF ... Exercises - español (Spanish) Bilingual PDF Health Information Translations Pendulum Exercises for Shoulder - English PDF Pendulum Exercises for ...

Plume Characterization of Busek 600W Hall Thruster

DTIC Science & Technology

2012-03-09

probe was used to examine the thruster plume current density while the ion species fractions were determined by the ExB probe. The inverted pendulum ...25 A. Inverted Pendulum ...Diagnostic Equipment .....................................................................................45 A. Inverted Pendulum

Precessional Periods of Long and Short Foucault Pendulums

ERIC Educational Resources Information Center

Soga, Michitoshi

1978-01-01

Derives the precessional period of a Foucault pendulum without using small oscillation amplitudes. Shows that if the path of the pendulum passes through the origin, the periods for differing amplitudes are essentially the same. (GA)

Persistent Seismicity and Energetics of the 2010 Earthquake Sequence of the Gros Ventre-Teton Area, Wyoming

NASA Astrophysics Data System (ADS)

Farrell, J.

2010-12-01

Farrell, Jamie M. Smith, Robert Massin, Fred White, Bonnie Department of Geology and Geophysics University of Utah Salt Lake City, Utah 84112 Seismicity has persisted along a zone south of the Yellowstone volcanic field in the Gros Ventre Range, Wyoming, and on the eastern edge of the asesimic Quat. high slip-rate Teton fault. Concentrated seismicity has in this area occurs in sporadic sequences documented since 1923 with notable earthquakes in the decade preceding the deadly 1925 Gros Ventre slide that eventually lead to the failure of a dam blocked by the slide in 1927. Notable seismicity of the Gros Ventre region, using data from the Teton, Yellowstone and USArray seismic networks, has continued in the last decade with sequences in 2002, 2004, culminating in an energetic sequence beginning in May, 2009 through a sequence of more than 180 well located earthquakes mainly from August 5 to August 17 of 0.5

[Study on molecular recognition technology in active constituents extracted and isolated from Aconitum pendulum].

PubMed

Ma, Xue-Qin; Li, Guo-Shan; Fu, Xue-Yan; Ma, Jing-Zu

2011-03-01

To investigate CD molecular recognition technology applied in active constituents extracted and isolated from traditional Chinese medicine--Aconitum pendulum. The inclusion constant and form probability of the inclusion complex of Aconitum pendulum with p-CD was calculated by UV spectra method. The active constituents of Aconitum pendulum were extracted and isolated by molecular recognition technology. The inclusion complex was identified by UV. The chemical constituents of Aconitum pendulum and inclusion complex was determined by HPLC. The analgesic effects of inclusion complex was investigated by experiment of intraperitoneal injection of acetic acid in rats. The inclusion complex was identified and confirmed by UV spectra method, the chemical components of inclusion complex were simple, and the content of active constituents increased significantly, the analgesic effects of inclusion complex was well. The molecular recognition technology can be used for extracting and isolating active constituents of Aconitum pendulum, and the effects are obvious.

Charge management for gravitational-wave observatories using UV LEDs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pollack, S. E.; Turner, M. D.; Schlamminger, S.

Accumulation of electrical charge on the end mirrors of gravitational-wave observatories can become a source of noise limiting the sensitivity of such detectors through electronic couplings to nearby surfaces. Torsion balances provide an ideal means for testing gravitational-wave technologies due to their high sensitivity to small forces. Our torsion pendulum apparatus consists of a movable plate brought near a plate pendulum suspended from a nonconducting quartz fiber. A UV LED located near the pendulum photoejects electrons from the surface, and a UV LED driven electron gun directs photoelectrons towards the pendulum surface. We have demonstrated both charging and discharging ofmore » the pendulum with equivalent charging rates of {approx}10{sup 5}e/s, as well as spectral measurements of the pendulum charge resulting in a white noise level equivalent to 3x10{sup 5}e/{radical}(Hz).« less

The Reproduction of Scientific Understanding about Pendulum Motion in the Public

NASA Astrophysics Data System (ADS)

Manabu, Sumida

This paper describes life-span development of understanding about pendulum motion and effects of school science. The subjects were 2,766 people ranging from kindergartners up to 88 years senior citizens. The conflict and consensus between children and their parent's understanding of pendulum motion were also analyzed. The kindergartner's understanding, mostly non-scientific, made a marked developmental change to another type of non-scientific understanding by the time they reach G 4. Parents with scientific understanding do not presumably nurture scientifically minded children,even though about half of them can apply scientific conceptions that shorter pendulums swing faster, and the amplitude and speed of pendulum motion do not depend on its weight. There seems to be another type of developmental change from scientific understanding to non-scientific understanding around their fifties. Itis suggested that the scientific understanding in the public about pendulum motion become predominant due to the educational intervention through school science.

Design and Experimental Implementation of Optimal Spacecraft Antenna Slews

DTIC Science & Technology

2013-12-01

LINK PENDULUM MODEL ............................................................58  C.  AZIMUTH-ELEVATION SYSTEM...BOUNDARY VALUE PROBLEM ......................77  B.  DOUBLE PENDULUM EXAMPLE............................................................82  C.  SOLVING THE...Figure 15.  Two-link Pendulum .........................................................................................58  Figure 16.  Double

Motion of a pendulum with damping and vibrating axis of suspension at unconventional values of parameters

NASA Astrophysics Data System (ADS)

Demidov, Ivan; Sorokin, Vladislav

2018-05-01

Motion of a pendulum with damping and vibrating axis of suspension is considered at unconventional values of parameters. Case when the frequency of external loading and the natural frequency of the pendulum in the absence of this loading are of the same order is studied. Vibration intensity is assumed to be relatively low. In this case, the corresponding equation of the pendulum's motions doesn't involve an explicit small parameter. To solve the equation a new modification of the method of direct separation of motions is used. As the result, stability conditions of the pendulum inverted position are determined. Effects of damping on these conditions are discussed.

A novel real-time data acquisition using an Excel spreadsheet in pendulum experiment tool with light-based timer

NASA Astrophysics Data System (ADS)

Adhitama, Egy; Fauzi, Ahmad

2018-05-01

In this study, a pendulum experimental tool with a light-based timer has been developed to measure the period of a simple pendulum. The obtained data was automatically recorded in an Excel spreadsheet. The intensity of monochromatic light, sensed by a 3DU5C phototransistor, dynamically changes as the pendulum swings. The changed intensity varies the resistance value and was processed by the microcontroller, ATMega328, to obtain a signal period as a function of time and brightness when the pendulum crosses the light. Through the experiment, using calculated average periods, the gravitational acceleration value has been accurately and precisely determined.

Pendulum Mass Affects the Measurement of Articular Friction Coefficient

PubMed Central

Akelman, Matthew R.; Teeple, Erin; Machan, Jason T.; Crisco, Joseph J.; Jay, Gregory D.; Fleming, Braden C.

2012-01-01

Friction measurements of articular cartilage are important to determine the relative tribologic contributions made by synovial fluid or cartilage, and to assess the efficacy of therapies for preventing the development of post-traumatic osteoarthritis. Stanton’s equation is the most frequently used formula for estimating the whole joint friction coefficient (μ) of an articular pendulum, and assumes pendulum energy loss through a mass-independent mechanism. This study examines if articular pendulum energy loss is indeed mass independent, and compares Stanton’s model to an alternative model, which incorporates viscous damping, for calculating μ. Ten loads (25-100% body weight) were applied in a random order to an articular pendulum using the knees of adult male Hartley guinea pigs (n = 4) as the fulcrum. Motion of the decaying pendulum was recorded and μ was estimated using two models: Stanton’s equation, and an exponential decay function incorporating a viscous damping coefficient. μ estimates decreased as mass increased for both models. Exponential decay model fit error values were 82% less than the Stanton model. These results indicate that μ decreases with increasing mass, and that an exponential decay model provides a better fit for articular pendulum data at all mass values. In conclusion, inter-study comparisons of articular pendulum μ values should not be made without recognizing the loads used, as μ values are mass dependent. PMID:23122223

Pendulum mass affects the measurement of articular friction coefficient.

PubMed

Akelman, Matthew R; Teeple, Erin; Machan, Jason T; Crisco, Joseph J; Jay, Gregory D; Fleming, Braden C

2013-02-01

Friction measurements of articular cartilage are important to determine the relative tribologic contributions made by synovial fluid or cartilage, and to assess the efficacy of therapies for preventing the development of post-traumatic osteoarthritis. Stanton's equation is the most frequently used formula for estimating the whole joint friction coefficient (μ) of an articular pendulum, and assumes pendulum energy loss through a mass-independent mechanism. This study examines if articular pendulum energy loss is indeed mass independent, and compares Stanton's model to an alternative model, which incorporates viscous damping, for calculating μ. Ten loads (25-100% body weight) were applied in a random order to an articular pendulum using the knees of adult male Hartley guinea pigs (n=4) as the fulcrum. Motion of the decaying pendulum was recorded and μ was estimated using two models: Stanton's equation, and an exponential decay function incorporating a viscous damping coefficient. μ estimates decreased as mass increased for both models. Exponential decay model fit error values were 82% less than the Stanton model. These results indicate that μ decreases with increasing mass, and that an exponential decay model provides a better fit for articular pendulum data at all mass values. In conclusion, inter-study comparisons of articular pendulum μ values should not be made without recognizing the loads used, as μ values are mass dependent. Copyright © 2012 Elsevier Ltd. All rights reserved.

Maxillary molar distalization: Pendulum and Fast-Back, comparison between two approaches for Class II malocclusion.

PubMed

Caprioglio, Alberto; Beretta, Matteo; Lanteri, Claudio

2011-01-01

To compare the dento-alveolar and skeletal effects produced by two different molar intraoral distalization appliances, Pendulum and Fast-Back, both followed by fixed appliances, in the treatment of Class II malocclusion. 41 patients for Pendulum (18 males and 23 females) and 35 for Fast-Back (14 males and 21 females) were selected, with a mean age at the start of treatment of 12.11 years in the Pendulum group and 13.3 for in the Fast-Back group. The durations of the distalization phase were 8 months in the Pendulum group and 9 months in the Fast-Back group, and the durations of the second phase of treatment with fixed appliances were 19 months in the Pendulum group and 20 months in the Fast-Back group. Lateral cephalograms were analyzed at 3 observation times: before treatment, after distalization and after comprehensive orthodontic treatment. During molar distalization the Pendulum subjects showed greater distal molar movement and less anchorage loss at both the premolars and maxillary incisors than the Fast-Back subjects. Pendulum and Fast-Back produced similar amounts of distal molar movement and overcorrection of molar relationship at the end of distalization though the Fast-Back induced a more bodily movement. Very little change occurred in the inclination of the mandibular plane at the end of the 2-phase treatment in both groups. At the end of treatment the maxillary first molars were on average 1mm more distal in the Pendulum group compared to the Fast-Back group, while the total molar correction was 3.2mm with 3.9° of distal inclination for the Pendulum and 2mm with 1.1° of mesial inclination for the Fast-Back. Both appliance were equally effective in inducing a satisfactory Class I relationship in 97.2% of the cases. The Pendulum and the Fast-Back induce similar dentoskeletal effects. The use of the two distalization devices, therefore, can be considered clinically equivalent. Copyright © 2011 Società Italiana di Ortodonzia SIDO. Published by Elsevier Srl. All rights reserved.

Probing the frontal deformation zone of the Chihshang Fault with boreholes and high-resolution electrical resistivity imaging methods: A case study at the Dapo site in eastern Taiwan

NASA Astrophysics Data System (ADS)

Chang, Ping-Yu; Huang, Wen-Jeng; Chen, Chien-Chih; Hsu, Han-lun; Yen, I.-Chin; Ho, Gong-Ruei; Lee, Jian-Cheng; Lu, Shih-Ting; Chen, Po-Tsun

2018-06-01

Not only direct fault ruptures but also later mass movement may result in complicated frontal deformation of the faults. Consequently, the deformation front or the contacts between the unconsolidated materials from the hanging wall and footwall of the thrust fault may indicate the toe of the mass movement instead of the actual fault zone. In this study, we used a combination of surface electrical resistivity imaging methods and borehole records in order to investigate the geometries of the structures in the frontal deformation zone of the Chihshang Fault at the Dapo elementary school. From the cores, we observed three different geological components at the Dapo site: the conductive Lichi mélange of the hanging wall, the colluvial gravels and the underlying fluvial-gravel layer at the footwall. The resistivity images from two parallel survey lines reveal that the position where the fault trace was thought to be is actually the toe of the slumping body's surface ruptures consisting of materials from the Lichi mélange. On the basis of the resistivity images, we also found that the actual fault plane is located on the southeastern side of the resistivity survey line near the hilltop. As a result, we conclude that mass movement induced by the inter-seismic creeping, not direct faulting, is the main factor affecting the frontal deformation zone of the Chihshang fault at the Dapo site.

Square-Wave Model for a Pendulum with Oscillating Suspension

ERIC Educational Resources Information Center

Yorke, Ellen D.

1978-01-01

Demonstrates that if a sinusoidal oscillation of the point of support of a pendulum is approximated by a square wave, a matrix method may be used to discuss parametric resonance and the stability of the inverted pendulum. (Author/SL)

Examining Functions in Mathematics and Science Using Computer Interfacing.

ERIC Educational Resources Information Center

Walton, Karen Doyle

1988-01-01

Introduces microcomputer interfacing as a method for explaining and demonstrating various aspects of the concept of function. Provides three experiments with illustrations and typical computer graphic displays: pendulum motion, pendulum study using two pendulums, and heat absorption and radiation. (YP)

Distribution of garnet grain sizes and morphologies across the Moine Supergroup, northern Scottish Caledonides

NASA Astrophysics Data System (ADS)

Ashley, Kyle T.; Thigpen, J. Ryan; Law, Richard D.

2016-04-01

Garnet is used in a wide range of geologic studies due to its important physical and chemical characteristics. While the mineral is useful for thermobarometry and geochronology constraints and can often be correlated to deformation and fabric development, difficulties remain in making meaningful interpretations of such data. In this study, we characterize garnet grain sizes and crystal morphologies from 141 garnet-bearing metasedimentary rock samples collected from the northern part of the Moine Supergroup in the Scottish Caledonides. Larger, euhedral crystals are indicative of prograde metamorphic growth and are typically associated with the most recent phase of orogenesis (Scandian, ˜430 Ma). Small, rounded ("pin-head") garnets are interpreted as detrital in origin. A subhedral classification is more subjective and is used when garnets contains portions of straight boundaries but have rounded edges or rims that have been altered through retrograde metamorphic reactions. From our collection, 88 samples contain anhedral garnets (maximum measured grain size d = 0.46 ± 0.21 mm), 34 bear subhedral garnets (d = 2.0 ± 1.0 mm), and the remaining 19 samples contain garnets with euhedral grains (d = 4.4 ± 2.6 mm). Plotting the distribution of garnets relative to the mapped thrust contacts reveals an abrupt change in morphology and grain size when traced from the Moine thrust sheet across the Ben Hope and Sgurr Beag thrusts into the higher-grade, more hinterland-positioned thrust sheets. The dominance of anhedral garnets in the Moine thrust sheet suggests that these grains should not be used for peak P - T estimation associated with relatively low temperature (<500 ° C) Scandian metamorphism, as they are likely detrital in origin and contain protolith chemical signatures that would not have been reset due to sluggish diffusivities at greenschist facies temperatures. However, chemical and isotopic data from these grains may provide information into the provenance of these metasediments. A thermal/chemical break must occur at the Ben Hope thrust, because hanging wall garnets contain euhedral (Scandian?) rims that are distinct from the garnet grains observed in the underlying Moine thrust sheet. In addition to morphology, the propensity of garnet to include minerals during growth makes it a useful phase for obtaining a historical perspective on growth conditions. The distribution and chemistries of minerals included/encapsulated by garnet was studied for various samples to gain insight into metamorphic evolution and to distinguish garnets that likely contain multiple generations of growth. Although our results are specific to the Caledonides of northern Scotland, this work highlights the general necessity of a comprehensive petrographic assessment of garnet grains in advance of interpreting large suits of garnet-derived thermodynamic and geochronologic data.

Course of Near-hanging Victims Succumbed to Death: A Seven Year Study

PubMed Central

Mugadlimath, Anand B.; Zine, K.U.; Farooqui, Jamebaseer M.; Phalke, Balaji J.

2015-01-01

Introduction: Near hanging refers to victims who survive a hanging injury following attempted hanging, long enough to reach hospital. Delayed deaths in near hanging patients are mostly due to complication of hanging. The purpose of this study was to evaluate the demographics, mortality patterns and cause of delayed deaths in near hanging victims. Materials and Methods: In this study autopsy files over a seven year period from 2007 to 2013 were reviewed, and data of near hanging deaths (attempted hanging cases who succumbed to death and subjected for medicolegal autopsy) was extracted. Records of 14,000 autopsies was reviewed, and 10 deceased having died delayed deaths after near hanging episode were identified. In each case, the patients’ details, including gender, age, type of suspension, type of ligature material used for hanging and subsequent hanging mark produced were reviewed using autopsy reports and photographs taken during autopsy. Results: Demographic and pathological aspects of the each case discussed to throw light on autopsy findings in victims who died following near hanging. Complete suspension was present in 3 cases, while partial suspension was present in 7 cases. Survivals in delayed death after near hanging episode have ranged from 9 h to 72 d. Hypoxic encephalopathy was the most common cause of death, followed by pneumonia. Conclusion: Most of the near hanging patients did succumb to hypoxic encephalopathy; however, consolidation of lungs (pneumonia) was the next common cause of death reflecting need for aggressive oxygen therapy and selective resuscitation should be performed in all such cases. PMID:25954634

Control of Torsional Vibrations by Pendulum Masses

NASA Technical Reports Server (NTRS)

Stieglitz, Albert

1942-01-01

Various versions of pendulum masses have been developed abroad within the past few years by means of which resonant vibrations of rotating shafts can be eliminated at a given tuning. They are already successfully employed on radial engines in the form of pendulous counterweights. Compared with the commonly known torsional vibration dampers, the pendulum masses have the advantage of being structurally very simple, requiring no internal damping and being capable of completely eliminating certain vibrations. Unexplained, so far, remains the problem of behavior of pendulum masses in other critical zones to which they are not tuned, their dynamic behavior at some tuning other than in resonance, and their effect within a compound vibration system and at simultaneous application of several differently tuned pendulous masses. These problems are analyzed in the present report. The results constitute an enlargement of the scope of application of pendulum masses, especially for in-line engines. Among other things it is found that the natural frequency of a system can be raised by means of a correspondingly tuned pendulum mass. The formulas necessary for the design of any practical version are developed, and a pendulum mass having two different natural frequencies simultaneously is described.

A novel pendulum test for measuring roller chain efficiency

NASA Astrophysics Data System (ADS)

Wragge-Morley, R.; Yon, J.; Lock, R.; Alexander, B.; Burgess, S.

2018-07-01

This paper describes a novel pendulum decay test for determining the transmission efficiency of chain drives. The test involves releasing a pendulum with an initial potential energy and measuring its decaying oscillations: under controlled conditions the decay reveals the losses in the transmission to a high degree of accuracy. The main advantage over motorised rigs is that there are significantly fewer sources of friction and inertia and hence measurement error. The pendulum rigs have an accuracy around 0.6% for the measurement of the coefficient of friction, giving an accuracy of transmission efficiency measurement around 0.012%. A theoretical model of chain friction combined with the equations of motion enables the coefficient of friction to be determined from the decay rate of pendulum velocity. The pendulum rigs operate at relatively low speeds. However, they allow an accurate determination of the coefficient of friction to estimate transmission efficiency at higher speeds. The pendulum rig revealed a previously undetected rocking behaviour in the chain links at very small articulation angles. In this regime, the link interfaces were observed to roll against one another rather than slide. This observation indicates that a very high-efficiency transmission can be achieved if the articulation angle is very low.

Late extension in compressional wedges above a weak, viscous décollement: results from analogue modeling

NASA Astrophysics Data System (ADS)

Borderie, Sandra; Vendeville, Bruno C.; Graveleau, Fabien; Witt, César

2016-04-01

Extension during convergence is a structural process commonly encountered in different geodynamic settings, such as accretionary wedges subjected to tectonic erosion, or mountain belts undergoing post-orogenic collapse. This has been investigated with experimental models at the scale of doubly-vergent wedges (Haq and Davis 2008; Bonini et al. 2000, Buck and Sokoutis 1994) but not thoroughly at the scale of fold-and-thrust belts. During an experimental investigation carried out on the behavior of segmented fold-and-thrust belts induced by stratigraphic inheritance in the foreland series (Borderie et al., EGU this session), unexpected shallow normal faulting occurred. The models comprised one basal frictional décollement (glass microbeads) and one upper viscous décollement embedded in the cover (silicone polymer). Extension took place during the late stages of the experiments and it was localized at the transition zone between the rear domain of the wedge and the frontal fold-and-thrust belt that detached on the upper viscous décollement. Normal faults strike parallel to the compressional structures and mainly dip toward the foreland. They root in the viscous décollement. Through a series of parametrized experiments dedicated to constrain the timing of formation of these extensional structures, we could evidence that these normal faults appear once the bulk shortening in the rear domain has created enough uplift of the internal zone by antiformal stacking and enough forelandward tilting of the upper viscous décollement. These two latter mechanisms are direct consequences of the whole wedge dynamics that links the thrust fault dynamics in the upper shallow sedimentary sequence and the thrust dynamics of the deep subsalt basement. The occurrence of this extension depends on the initial position of the upper viscous décollement and notably the position of the internal pinchout relative to the position of the backstop. Additional tests have also demonstrated that this extension is prevented by surface processes and notably sedimentation. We compare our experimental findings with natural examples of extensional features in various fold-and-thrust belts and accretionary features across the world (e.g. the Mediterranean ridge). References: Bonini, Marco, Dimitrios Sokoutis, Genene Mulugeta, and Emmanouil Katrivanos. 2000. "Modelling Hanging Wall Accommodation above Rigid Thrust Ramps." Journal of Structural Geology 22 (8): 1165-79. Borderie, Sandra, Fabien Graveleau, Cesar Witt and Bruno C. Vendeville. 2016. "Analogue modeling of 3-D structural segmentation in fold-and-thrust belts: interactions between frictional and viscous provinces in foreland basins." Gephys. Res. Abstr., 18, EGU2016-Vienne. Buck, W Roger, and Dimitrios Sokoutis. 1994. "Analogue Model of Gravitational Collapse and Surface Extension during Continental Convergence." Nature 369: 737-40. Haq, Saad SB, and Dan M. Davis. 2008. "Extension during Active Collision in Thin-Skinned Wedges: Insights from Laboratory Experiments." Geology 36 (6): 475-78.

A Discrete Element Modeling Approach to Exploring the Transition Between Fault-related Folding Styles

NASA Astrophysics Data System (ADS)

Hughes, A. N.; Benesh, N. P.; Alt, R. C., II; Shaw, J. H.

2011-12-01

Contractional fault-related folds form as stratigraphic layers of rock are deformed due to displacement on an underlying fault. Specifically, fault-bend folds form as rock strata are displaced over non-planar faults, and fault-propagation folds form at the tips of faults as they propagate upward through sedimentary layers. Both types of structures are commonly observed in fold and thrust belts and passive margin settings throughout the world. Fault-bend and fault-propagation folds are often seen in close proximity to each other, and kinematic analysis of some fault-related folds suggests that they have undergone a transition in structural style from fault-bend to fault-propagation folding during their deformational history. Because of the similarity in conditions in which both fault-bend and fault-propagation folds are found, the circumstances that promote the formation of one of these structural styles over the other is not immediately evident. In an effort to better understand this issue, we have investigated the role of mechanical and geometric factors in the transition between fault-bend folding and fault-propagation folding using a series of models developed with the discrete element method (DEM). The DEM models employ an aggregate of circular, frictional disks that incorporate bonding at particle contacts to represent the numerical stratigraphy. A vertical wall moving at a fixed velocity drives displacement of the hanging-wall section along a pre-defined fault ramp and detachment. We utilize this setup to study the transition between fault-bend and fault-propagation folding by varying mechanical strength, stratigraphic layering, fault geometries, and boundary conditions of the model. In most circumstances, displacement of the hanging-wall leads to the development of an emergent fold as the hanging-wall material passes across the fault bend. However, in other cases, an emergent fault propagates upward through the sedimentary section, associated with the development of a steep, narrow front-limb, characteristic of fault-propagation folding. We find that the boundary conditions imposed on the far wall of the model have the strongest influence on structural style, but that other factors, such as fault dip and mechanical strengths, play secondary roles. By testing a range of values for each of the parameters, we are able to identify the range of values under which the transition occurs. Additionally, we find that the transition between fault-bend and fault-propagation folding is gradual, with structures in the transitional regime showing evidence of each structural style during a portion of their history. The primary role that boundary conditions play in determining fault-related folding style implies that the growth of natural structures may be affected by the emergence of adjacent structures, or in distal variations in detachment strengths. We explore these relationships using natural examples from various fold-and-thrust belts.

Quadriceps femoris spasticity in children with cerebral palsy: measurement with the pendulum test and relationship with gait abnormalities.

PubMed

Szopa, Andrzej; Domagalska-Szopa, Małgorzata; Kidoń, Zenon; Syczewska, Małgorzata

2014-12-16

Development of a reliable and objective test of spasticity is important for assessment and treatment of children with cerebral palsy. The pendulum test has been reported to yield reliable measurements of spasticity and to be sensitive to variations in spasticity in these children. However, the relationship between the pendulum test scores and other objective measures of spasticity has not been studied. The present study aimed to assess the effectiveness of an accelerometer-based pendulum test as a measurement of spasticity in CP, and to explore the correlation between the measurements of this test and the global index of deviation from normal gait in in children with cerebral palsy. We studied thirty-six children with cerebral palsy, including 18 with spastic hemiplegia and 18 with spastic diplegia, and a group of 18 typically-developing children. Knee extensor spasticity was assessed bilaterally using the accelerometer-based pendulum test and three-dimensional gait analysis. The Gillette Gait Index was calculated from the results of the gait analysis. The data from the accelerometer-based pendulum test could be used to distinguish between able-bodied children and children with cerebral palsy. Additionally, two of the measurements, first swing excursion and relaxation index, could be used to differentiate the degree of knee extensor spasticity in the children with cerebral palsy. Only a few moderate correlations were found between the Gillette Gait Index and the pendulum test data. This study demonstrates that the pendulum test can be used to discriminate between typically developing children and children with CP, as well as between various degrees of spasticity, such as spastic hemiplegia and spastic diplegia, in the knee extensor muscle of children with CP. Deviations from normal gait in children with CP were not correlated with the results of the pendulum test.

Comparison of the effects produced by headgear and pendulum appliances followed by fixed orthodontic treatment.

PubMed

Angelieri, Fernanda; de Almeida, Renato Rodrigues; Janson, Guilherme; Castanha Henriques, José Fernando; Pinzan, Arnaldo

2008-12-01

This study compared the effects produced by two different molar distalizers, namely cervical headgear (CHG) and the intraoral pendulum appliance, associated with fixed orthodontic appliances. The headgear group comprised 30 patients (19 females, 11 males), with an initial age of 13.07 years [standard deviation (SD) = 1.3], treated with CHG and fixed orthodontic appliances for a mean period of 3.28 years, and the pendulum group 22 patients (15 females, 7 males), with initial age of 13.75 years (SD = 1.86), treated with the pendulum appliance followed by fixed orthodontic appliances for a mean period of 4.12 years. Lateral cephalograms were taken at the start (T1) and on completion (T2) of orthodontic treatment. The pendulum and CHG groups were similar as to initial age, severity of the Class II malocclusion, gender distribution, initial cephalometric characteristics, and initial and final treatment priority index (TPI). Only treatment time was not similar between the groups, with a need for annualization for data for the pendulum group. The data were compared with independent t-tests. There was significantly greater restriction of maxillary forward growth and improvement of the skeletal maxillomandibular relationship in the CHG group (P < 0.05). The maxillary molars were more mesially tipped and extruded and the mandibular molars more uprighted in the CHG group compared with the pendulum group (P < 0.05). There was more labial tipping of the mandibular incisors and greater overbite reduction in the pendulum group. The pendulum appliance produced only dentoalveolar effects, different from the CHG appliance, which restricted maxillary forward displacement, thus improving the skeletal maxillomandibular relationship.

Analyzing spring pendulum phenomena with a smart-phone acceleration sensor

NASA Astrophysics Data System (ADS)

Kuhn, Jochen; Vogt, Patrik

2012-11-01

This paper describes two further pendulum experiments using the acceleration sensor of a smartphone in this column (for earlier contributions concerning this topic, including the description of the operation and use of the acceleration sensor, see Refs. 1 and 2). In this paper we focus on analyzing spring pendulum phenomena. Therefore two spring pendulum experiments will be described in which a smartphone is used as a pendulum body and SPARKvue3 software is used in conjunction with an iPhone or an iPod touch, or the Accelogger4 app for an Android device.1,2 As described in Ref. 1, the values measured by the smartphone are subsequently exported to a spreadsheet application (e.g., MS Excel) for analysis.

Applying Low Temperature Thermochronology to Constrain Exhumation Patterns along the Eastern Denali Fault Corner, Alaska

NASA Astrophysics Data System (ADS)

Warfel, T. S.; Fitzgerald, P. G.; Benowitz, J.; Ridgway, K.; Allen, W. K.

2017-12-01

The Denali Fault (DF) constitutes a long ( 2000 km), arcuate, dextrally transpressive intracontinental fault system sketching across south-central Alaska. Strain-partitioning along the DF is accommodated as slip on the fault and fault-normal motion on a series of thrusts located north and south of the fault itself. High topography in the central and eastern Alaska Range, also locations of the greatest exhumation along the fault, are associated with restraining bends in those regions. East of the Richardson Highway, along the eastern Denali fault corner (or east-central segment of the DF), thrust faults south of the DF, including the McCallum thrust have accommodated the fault-normal component of motion along the DF. The aim of this project is to better understand what controls exhumation along large strike-slip faults, in particular the DF. Previous work along the DF in the central and eastern Alaska Range (to the west of this region) indicate the importance of fault geometry and rheological contrasts between terranes that have been juxtaposed against one another in controlling the location of exhumation. Our area of interest is a largely unstudied section along the Denali Fault (eastern DF corner) located between the DF/Hines Creek fault intersection and the Totschunda/DF intersection. We are applying a combination of apatite fission track thermochronology and apatite (U-Th)/He dating to samples collected north and south of the DF, and across thrust faults south of the DF. Thermochronology is being applied to bedrock samples, collected in vertical profiles and/or hanging wall - footwall pairs. Cobbles were also collected within a stratigraphic framework (constrained by tephras), from Miocene sediments in inverted basins south of the DF. Thermochronologic data from these cobbles; using lag-time analyses and inverse thermal models, will constrain the exhumation history of the hinterland. Assuming modern rates for slip along the DF will allow constraints to be placed on spatial and temporal patterns of exhumation and hence, help constrain the underlying control on exhumation patterns. Preliminary results indicate older AFT and AHe ages (up to 50 Ma) away from the DF but yield apatite (U-Th)/He ages as young as 2 Ma for a sample from the footwall of the closest thrust south of the DF.

Shallow seismicity of arc-continent collision near Lae, Papua New Guinea

NASA Astrophysics Data System (ADS)

Kulig, Christopher; McCaffrey, Robert; Abers, Geoffrey A.; Letz, Horst

1993-11-01

In northeastern New Guinea, the narrow Ramu-Markham Valley (RMV) separates island arc rocks to the north from those of continental origin to the south and appears to be the western, onland extension of the New Britain trench. To explore the tectonic processes at the leading edge of the island arc during collision, we operated a portable seismic network for six weeks near the city of Lae at the eastern end of the RMV. We observed a narrow, near-vertical belt of seismicity between 10 and 30 km depth, that we call the Lae Seismic Zone (LSZ), starting at the RMV in the southwest and trending northeasterly cutting across surface geologic structure. The truncation of the LSZ along a steep plane by the Ramu-Markham Fault Zone (RMFZ) and earthquake first motions suggest that the earthquakes occur in the hanging wall of a steep, N-dipping fault that crops out at the RMFZ. We also consider that the LSZ is within the lower plate of a gently dipping thrust. Below 20 km depth the microearthquake zone is truncated by a gently, NE-dipping plane coinciding in depth and dip with nodal planes of recent large ( mb = 5.6 and 6.0) thrust earthquakes. We suggest that the Huon Peninsula is being emplaced onto the Australian plate along a gently (~ 25°) dipping thrust fault that is 20 km deep beneath Lae. The RMFZ may be a steeply dipping thrust fault that connects with this gently, N-dipping thrust but accommodates little convergence at present. The LSZ trends nearly perpendicular to an anticlinal range which appears to be sheared in a left-lateral sense. P-wave first motions for earthquakes in the LSZ with steep (70° to 90° dip) nodal planes that strike parallel to the LSZ suggest a component of south-side-up displacement also. Hence, the crustal block south of the LSZ may be rising relative to the Huon Peninsula and the rapid Quaternary uplift rates estimated for the Lae coastal region may be higher than the uplift rate of the Huon Peninsula as a whole. We suggest that the LSZ reveals a tear of small offset in the Huon terrane but may be similar to a structure that produced a magnitude 7 earthquake near Madang in 1970.

Magnetic effect in the test of the weak equivalence principle using a rotating torsion pendulum

NASA Astrophysics Data System (ADS)

Zhu, Lin; Liu, Qi; Zhao, Hui-Hui; Yang, Shan-Qing; Luo, Pengshun; Shao, Cheng-Gang; Luo, Jun

2018-04-01

The high precision test of the weak equivalence principle (WEP) using a rotating torsion pendulum requires thorough analysis of systematic effects. Here we investigate one of the main systematic effects, the coupling of the ambient magnetic field to the pendulum. It is shown that the dominant term, the interaction between the average magnetic field and the magnetic dipole of the pendulum, is decreased by a factor of 1.1 × 104 with multi-layer magnetic shield shells. The shield shells reduce the magnetic field to 1.9 × 10-9 T in the transverse direction so that the dipole-interaction limited WEP test is expected at η ≲ 10-14 for a pendulum dipole less than 10-9 A m2. The high-order effect, the coupling of the magnetic field gradient to the magnetic quadrupole of the pendulum, would also contribute to the systematic errors for a test precision down to η ˜ 10-14.

Magnetic effect in the test of the weak equivalence principle using a rotating torsion pendulum.

PubMed

Zhu, Lin; Liu, Qi; Zhao, Hui-Hui; Yang, Shan-Qing; Luo, Pengshun; Shao, Cheng-Gang; Luo, Jun

2018-04-01

The high precision test of the weak equivalence principle (WEP) using a rotating torsion pendulum requires thorough analysis of systematic effects. Here we investigate one of the main systematic effects, the coupling of the ambient magnetic field to the pendulum. It is shown that the dominant term, the interaction between the average magnetic field and the magnetic dipole of the pendulum, is decreased by a factor of 1.1 × 10 4 with multi-layer magnetic shield shells. The shield shells reduce the magnetic field to 1.9 × 10 -9 T in the transverse direction so that the dipole-interaction limited WEP test is expected at η ≲ 10 -14 for a pendulum dipole less than 10 -9 A m 2 . The high-order effect, the coupling of the magnetic field gradient to the magnetic quadrupole of the pendulum, would also contribute to the systematic errors for a test precision down to η ∼ 10 -14 .

Development of Gravity Acceleration Measurement Using Simple Harmonic Motion Pendulum Method Based on Digital Technology and Photogate Sensor

NASA Astrophysics Data System (ADS)

Yulkifli; Afandi, Zurian; Yohandri

2018-04-01

Development of gravitation acceleration measurement using simple harmonic motion pendulum method, digital technology and photogate sensor has been done. Digital technology is more practical and optimizes the time of experimentation. The pendulum method is a method of calculating the acceleration of gravity using a solid ball that connected to a rope attached to a stative pole. The pendulum is swung at a small angle resulted a simple harmonic motion. The measurement system consists of a power supply, Photogate sensors, Arduino pro mini and seven segments. The Arduino pro mini receives digital data from the photogate sensor and processes the digital data into the timing data of the pendulum oscillation. The calculation result of the pendulum oscillation time is displayed on seven segments. Based on measured data, the accuracy and precision of the experiment system are 98.76% and 99.81%, respectively. Based on experiment data, the system can be operated in physics experiment especially in determination of the gravity acceleration.

Instability dynamics and breather formation in a horizontally shaken pendulum chain.

PubMed

Xu, Y; Alexander, T J; Sidhu, H; Kevrekidis, P G

2014-10-01

Inspired by the experimental results of Cuevas et al. [Phys. Rev. Lett. 102, 224101 (2009)], we consider theoretically the behavior of a chain of planar rigid pendulums suspended in a uniform gravitational field and subjected to a horizontal periodic driving force applied to the pendulum pivots. We characterize the motion of a single pendulum, finding bistability near the fundamental resonance and near the period-3 subharmonic resonance. We examine the development of modulational instability in a driven pendulum chain and find both a critical chain length and a critical frequency for the appearance of the instability. We study the breather solutions and show their connection to the single-pendulum dynamics and extend our analysis to consider multifrequency breathers connected to the period-3 periodic solution, showing also the possibility of stability in these breather states. Finally we examine the problem of breather generation and demonstrate a robust scheme for generation of on-site and off-site breathers.

Mathematic study of the rotor motion with a pendulum selfbalancing device

NASA Astrophysics Data System (ADS)

Ivkina, O. P.; Ziyakaev, G. R.; Pashkov, E. N.

2016-09-01

The rotary machines used in manufacturing may become unbalanced leading to vibration. In some cases, the problem may be solved by installing self-balancing devices (SBDs). Certain factors, however, exhibit a pronounced effect on the efficiency of these devices. The objective of the research comprised of establishing the most beneficial spatial position of pendulums to minimize the necessary time to repair the rotor unbalance. The mathematical research of the motion of a rotor with pendulum SBDs in the situation of their misalignment was undertaken. This objective was achieved by using the Lagrange equations of the second type. The analysis identified limiting cases of location of the rotor unbalance vector and the vector of housing's unbalance relative to each other, as well as the minimum capacity of the pendulum. When determining pendulums ’ parameters during the SBD design process, it is necessary to take into account the rotor unbalance and the unbalance of the machine body, which is caused by the misalignment of rotor axis and pendulum's axis of rotation.

Development of a software-hardware complex for studying the process of grinding by a pendulum deformer

NASA Astrophysics Data System (ADS)

Borisov, A. P.

2018-01-01

The article is devoted to the development of a software and hardware complex for investigating the grinding process on a pendulum deformer. The hardware part of this complex is the Raspberry Pi model 2B platform, to which a contactless angle sensor is connected, which allows to obtain data on the angle of deviation of the pendulum surface, usb-cameras, which allow to obtain grain images before and after grinding, and stepping motors allowing lifting of the pendulum surface and adjust the clearance between the pendulum and the supporting surfaces. The program part of the complex is written in C # and allows receiving data from the sensor and usb-cameras, processing the received data, and also controlling the synchronous-step motors in manual and automatic mode. The conducted studies show that the rational mode is the deviation of the pendulum surface by an angle of 400, and the location of the grain in the central zone of the support surface, regardless of the orientation of the grain in space. Also, due to the non-contact angle sensor, energy consumption for grinding, speed and acceleration of the pendulum surface, as well as vitreousness of grain and the energy consumption are calculated. With the help of photographs obtained from usb cameras, the work of a pendulum deformer based on the Rebinder formula and calculation of the grain area before and after grinding is determined.

On the Design and Test of a Liquid Injection Electric Thruster

NASA Technical Reports Server (NTRS)

Jones, T. A.; Kenney, J. T.; Youmans, E. H.

1973-01-01

A liquid injection electric thruster (LINJET) was designed and tested. The results of the tests were very encouraging with thruster performance levels well in excess of design goals. Supporting activities to the engine design and test included a five-million pulse life test on the main capacitor, a 46-million pulse test on the trigger electronics, design and fabrication of a zero resistance torque connector for use with the torsional pendulum thrust stand, design and fabrication of a logic box for control of engine firing, and a physical and chemical properties characterization of the perfluorocarbon propellant. While the results were encouraging, testing was limited, as many problems existed with the design. The most significant problem was involved with excessive propellant flow which contributed to false triggering and shorting. Low power active thermal control of the propellant storage cavity, coupled with a re-evaluation of the injection ring pore size and area exposed to the main capacitor discharge are areas that should be investigated should this design be carried forward.

49 CFR 572.123 - Neck assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... with respect to the pendulum's longitudinal centerline between 74 degrees and 92 degrees. Within this... direction of preimpact flight with respect to the pendulum's longitudinal centerline between 85 degrees and... contact between the pendulum striker plate and the honeycomb material. (c) Test procedure. The test...

49 CFR 572.123 - Neck assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... with respect to the pendulum's longitudinal centerline between 74 degrees and 92 degrees. Within this... direction of preimpact flight with respect to the pendulum's longitudinal centerline between 85 degrees and... contact between the pendulum striker plate and the honeycomb material. (c) Test procedure. The test...

49 CFR 572.123 - Neck assembly and test procedure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... with respect to the pendulum's longitudinal centerline between 74 degrees and 92 degrees. Within this... direction of preimpact flight with respect to the pendulum's longitudinal centerline between 85 degrees and... contact between the pendulum striker plate and the honeycomb material. (c) Test procedure. The test...

49 CFR 572.123 - Neck assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... with respect to the pendulum's longitudinal centerline between 74 degrees and 92 degrees. Within this... direction of preimpact flight with respect to the pendulum's longitudinal centerline between 85 degrees and... contact between the pendulum striker plate and the honeycomb material. (c) Test procedure. The test...

49 CFR 572.123 - Neck assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... with respect to the pendulum's longitudinal centerline between 74 degrees and 92 degrees. Within this... direction of preimpact flight with respect to the pendulum's longitudinal centerline between 85 degrees and... contact between the pendulum striker plate and the honeycomb material. (c) Test procedure. The test...

Pendulum Phenomena and the Assessment of Scientific Inquiry Capabilities

ERIC Educational Resources Information Center

Zachos, Paul

2004-01-01

Phenomena associated with the "pendulum" present numerous opportunities for assessing higher order human capabilities related to "scientific inquiry" and the "discovery" of natural law. This paper illustrates how systematic "assessment of scientific inquiry capabilities", using "pendulum" phenomena, can provide a useful tool for classroom teachers…

Active faulting in apparently stable peninsular India: Rift inversion and a Holocene-age great earthquake on the Tapti Fault

NASA Astrophysics Data System (ADS)

Copley, Alex; Mitra, Supriyo; Sloan, R. Alastair; Gaonkar, Sharad; Reynolds, Kirsty

2014-08-01

We present observations of active faulting within peninsular India, far from the surrounding plate boundaries. Offset alluvial fan surfaces indicate one or more magnitude 7.6-8.4 thrust-faulting earthquakes on the Tapti Fault (Maharashtra, western India) during the Holocene. The high ratio of fault displacement to length on the alluvial fan offsets implies high stress-drop faulting, as has been observed elsewhere in the peninsula. The along-strike extent of the fan offsets is similar to the thickness of the seismogenic layer, suggesting a roughly equidimensional fault rupture. The subsiding footwall of the fault is likely to have been responsible for altering the continental-scale drainage pattern in central India and creating the large west flowing catchment of the Tapti river. A preexisting sedimentary basin in the uplifting hanging wall implies that the Tapti Fault was active as a normal fault during the Mesozoic and has been reactivated as a thrust, highlighting the role of preexisting structures in determining the rheology and deformation of the lithosphere. The slip sense of faults and earthquakes in India suggests that deformation south of the Ganges foreland basin is driven by the compressive force transmitted between India and the Tibetan Plateau. The along-strike continuation of faulting to the east of the Holocene ruptures we have studied represents a significant seismic hazard in central India.

The Pendulum Equation

ERIC Educational Resources Information Center

Fay, Temple H.

2002-01-01

We investigate the pendulum equation [theta] + [lambda][squared] sin [theta] = 0 and two approximations for it. On the one hand, we suggest that the third and fifth-order Taylor series approximations for sin [theta] do not yield very good differential equations to approximate the solution of the pendulum equation unless the initial conditions are…

Equilibrium and Stability of a Pendulum in an Orbiting Spaceship.

ERIC Educational Resources Information Center

Blitzer, Leon

1979-01-01

Investigates the behavior of a simple pendulum attached to a fixed point inside a satellite moving in a circular orbit about the earth. It is found that the number of equilibrium positions depends on the length of the pendulum and the location of the point of attachment. (HM)

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 572.17 - Neck.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline a... distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at time T as...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.7 - Neck.

Code of Federal Regulations, 2014 CFR

2014-10-01

... paragraph (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline... the straight line distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 572.143 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... subpart, shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal... rotation data channels are defined to be zero when the longitudinal centerline of the neck and pendulum are... of preimpact flight with respect to the pendulum's longitudinal centerline between 83 degrees and 93...

49 CFR 572.36 - Test conditions and instrumentation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... be mounted with its sensitive axis colinear with the pendulum's longitudinal centerline. (h) The... acceleration—Class 1000 (2) Neck forces—Class 1000 (3) Neck moments—Class 600 (4) Neck pendulum acceleration—Class 60 (5) Thorax and thorax pendulum acceleration—Class 180 (6) Thorax deflection—Class 180 (7) Knee...

49 CFR 572.17 - Neck.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline a... distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at time T as...

49 CFR 572.133 - Neck assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... pendulum's longitudinal centerline between 77 degrees and 91 degrees. During the time interval while the... respect to the pendulum's longitudinal centerline between 99 degrees and 114 degrees. During the time... force to occipital condyle. (3) Time-zero is defined as the time of initial contact between the pendulum...

49 CFR 572.17 - Neck.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline a... distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at time T as...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.17 - Neck.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline a... distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at time T as...

49 CFR 572.133 - Neck assembly and test procedure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... pendulum's longitudinal centerline between 77 degrees and 91 degrees. During the time interval while the... respect to the pendulum's longitudinal centerline between 99 degrees and 114 degrees. During the time... force to occipital condyle. (3) Time-zero is defined as the time of initial contact between the pendulum...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 572.153 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... subpart shall rotate in the direction of pre-impact flight with respect to the pendulum's longitudinal... shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal centerline... section, on the pendulum so the midsagittal plane of the headform is vertical and coincides with the plane...

49 CFR 572.143 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... subpart, shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal... rotation data channels are defined to be zero when the longitudinal centerline of the neck and pendulum are... of preimpact flight with respect to the pendulum's longitudinal centerline between 83 degrees and 93...

49 CFR 572.133 - Neck assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... pendulum's longitudinal centerline between 77 degrees and 91 degrees. During the time interval while the... respect to the pendulum's longitudinal centerline between 99 degrees and 114 degrees. During the time... force to occipital condyle. (3) Time-zero is defined as the time of initial contact between the pendulum...

49 CFR 572.173 - Neck assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... respect to the pendulum's longitudinal centerline between 76 degrees and 90 degrees. During the time..., referenced in Figure T3, shall rotate in the direction of preimpact flight with respect to the pendulum's... occipital condyle. (3) Time zero is defined as the time of initial contact between the pendulum striker...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 581.6 - Conditions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the vehicle if they are optional equipment. (b) Pendulum test conditions. The following conditions apply to the pendulum test procedures of § 581.7 (a) and (b). (1) The test device consists of a block... 1963. From the point of release of the device until the onset of rebound, the pendulum suspension...

49 CFR 572.173 - Neck assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... respect to the pendulum's longitudinal centerline between 76 degrees and 90 degrees. During the time..., referenced in Figure T3, shall rotate in the direction of preimpact flight with respect to the pendulum's... occipital condyle. (3) Time zero is defined as the time of initial contact between the pendulum striker...

49 CFR 572.153 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... subpart shall rotate in the direction of pre-impact flight with respect to the pendulum's longitudinal... shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal centerline... section, on the pendulum so the midsagittal plane of the headform is vertical and coincides with the plane...

Conical Pendulum--Linearization Analyses

ERIC Educational Resources Information Center

Dean, Kevin; Mathew, Jyothi

2016-01-01

A theoretical analysis is presented, showing the derivations of seven different linearization equations for the conical pendulum period "T", as a function of radial and angular parameters. Experimental data obtained over a large range of fixed conical pendulum lengths (0.435 m-2.130 m) are plotted with the theoretical lines and…

49 CFR 572.17 - Neck.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline a... distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at time T as...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.7 - Neck.

Code of Federal Regulations, 2012 CFR

2012-10-01

... paragraph (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline... the straight line distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at...

49 CFR 572.143 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... subpart, shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal... rotation data channels are defined to be zero when the longitudinal centerline of the neck and pendulum are... of preimpact flight with respect to the pendulum's longitudinal centerline between 83 degrees and 93...

49 CFR 572.173 - Neck assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... respect to the pendulum's longitudinal centerline between 76 degrees and 90 degrees. During the time..., referenced in Figure T3, shall rotate in the direction of preimpact flight with respect to the pendulum's... occipital condyle. (3) Time zero is defined as the time of initial contact between the pendulum striker...

49 CFR 572.133 - Neck assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... pendulum's longitudinal centerline between 77 degrees and 91 degrees. During the time interval while the... respect to the pendulum's longitudinal centerline between 99 degrees and 114 degrees. During the time... force to occipital condyle. (3) Time-zero is defined as the time of initial contact between the pendulum...

49 CFR 572.153 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... subpart shall rotate in the direction of pre-impact flight with respect to the pendulum's longitudinal... shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal centerline... section, on the pendulum so the midsagittal plane of the headform is vertical and coincides with the plane...

49 CFR 572.133 - Neck assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... pendulum's longitudinal centerline between 77 degrees and 91 degrees. During the time interval while the... respect to the pendulum's longitudinal centerline between 99 degrees and 114 degrees. During the time... force to occipital condyle. (3) Time-zero is defined as the time of initial contact between the pendulum...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.7 - Neck.

Code of Federal Regulations, 2013 CFR

2013-10-01

... paragraph (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline... the straight line distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at...

49 CFR 572.153 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... subpart shall rotate in the direction of pre-impact flight with respect to the pendulum's longitudinal... shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal centerline... section, on the pendulum so the midsagittal plane of the headform is vertical and coincides with the plane...

49 CFR 572.36 - Test conditions and instrumentation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... be mounted with its sensitive axis colinear with the pendulum's longitudinal centerline. (h) The... acceleration—Class 1000 (2) Neck forces—Class 1000 (3) Neck moments—Class 600 (4) Neck pendulum acceleration—Class 60 (5) Thorax and thorax pendulum acceleration—Class 180 (6) Thorax deflection—Class 180 (7) Knee...

Experiments with a Magnetically Controlled Pendulum

ERIC Educational Resources Information Center

Kraftmakher, Yaakov

2007-01-01

A magnetically controlled pendulum is used for observing free and forced oscillations, including nonlinear oscillations and chaotic motion. A data-acquisition system stores the data and displays time series of the oscillations and related phase plane plots, Poincare maps, Fourier spectra and histograms. The decay constant of the pendulum can be…

49 CFR 572.7 - Neck.

Code of Federal Regulations, 2010 CFR

2010-10-01

... paragraph (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline... the straight line distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at...

49 CFR 572.153 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... subpart shall rotate in the direction of pre-impact flight with respect to the pendulum's longitudinal... shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal centerline... section, on the pendulum so the midsagittal plane of the headform is vertical and coincides with the plane...

49 CFR 572.113 - Neck assembly.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Using neck brackets 78051-303 and -307, mount the head/neck assembly to the part 572 pendulum test... to the plane of motion of the pendulum's longitudinal centerline (see § 572.33, Figure 20, except... (horizontal surface at the base of the skull) rotation with respect to the pendulum's longitudinal centerline...

49 CFR 572.7 - Neck.

Code of Federal Regulations, 2011 CFR

2011-10-01

... paragraph (c) of this section, the head shall rotate in reference to the pendulum's longitudinal centerline... the straight line distance between (1) the position relative to the pendulum arm of the head center of gravity at time zero, and (2) the position relative to the pendulum arm of the head center of gravity at...

49 CFR 572.36 - Test conditions and instrumentation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... be mounted with its sensitive axis colinear with the pendulum's longitudinal centerline. (h) The... acceleration—Class 1000 (2) Neck forces—Class 1000 (3) Neck moments—Class 600 (4) Neck pendulum acceleration—Class 60 (5) Thorax and thorax pendulum acceleration—Class 180 (6) Thorax deflection—Class 180 (7) Knee...

49 CFR 572.36 - Test conditions and instrumentation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... be mounted with its sensitive axis colinear with the pendulum's longitudinal centerline. (h) The... acceleration—Class 1000 (2) Neck forces—Class 1000 (3) Neck moments—Class 600 (4) Neck pendulum acceleration—Class 60 (5) Thorax and thorax pendulum acceleration—Class 180 (6) Thorax deflection—Class 180 (7) Knee...

49 CFR 572.143 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... subpart, shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal... rotation data channels are defined to be zero when the longitudinal centerline of the neck and pendulum are... of preimpact flight with respect to the pendulum's longitudinal centerline between 83 degrees and 93...

49 CFR 572.36 - Test conditions and instrumentation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... be mounted with its sensitive axis colinear with the pendulum's longitudinal centerline. (h) The... acceleration—Class 1000 (2) Neck forces—Class 1000 (3) Neck moments—Class 600 (4) Neck pendulum acceleration—Class 60 (5) Thorax and thorax pendulum acceleration—Class 180 (6) Thorax deflection—Class 180 (7) Knee...

49 CFR 572.143 - Neck-headform assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... subpart, shall rotate in the direction of preimpact flight with respect to the pendulum's longitudinal... rotation data channels are defined to be zero when the longitudinal centerline of the neck and pendulum are... of preimpact flight with respect to the pendulum's longitudinal centerline between 83 degrees and 93...

"Time: What Is It that It Can Be Measured?"

ERIC Educational Resources Information Center

Raju, C. K.

2006-01-01

Experiments with the simple pendulum are easy, but its motion is nevertheless confounded with simple harmonic motion. However, refined theoretical models of the pendulum can, today, be easily taught using software like CALCODE. Similarly, the cycloidal pendulum is isochronous only in simplified theory. But what "are" theoretically equal intervals…

An analytical approach to the external force-free motion of pendulums on surfaces of constant curvature

NASA Astrophysics Data System (ADS)

Rubio, Rafael M.; Salamanca, Juan J.

2018-07-01

The dynamics of external force free motion of pendulums on surfaces of constant Gaussian curvature is addressed when the pivot moves along a geodesic obtaining the Lagrangian of the system. As an application it is possible the study of elastic and quantum pendulums.

The Pendulum and the Calculus.

ERIC Educational Resources Information Center

Sworder, Steven C.

A pair of experiments, appropriate for the lower division fourth semester calculus or differential equations course, are presented. The second order differential equation representing the equation of motion of a simple pendulum is derived. The period of oscillation for a particular pendulum can be predicted from the solution to this equation. As a…

Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, J.; Tang, J., E-mail: jtang@engr.uconn.edu

This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.

Design and Flight Test of a Cable Angle Feedback Control System for Improving Helicopter Slung Load Operations at Low Speed

DTIC Science & Technology

2014-04-01

improve the damping of the load pendulum motions, but the load feedback generally had the effect of making the load feel heavier to the pilot [28...0.25 2 1000lbs 16,000lbs 0.06 Another important parameter is the slung load pendulum frequency. Using a simple pendulum model, this natural...the expected yaw and heave modes. The presence of the load adds oscillatory pendulum modes in the pitch and roll axes, as expected. Table 2-3

A simple, low-cost, data logging pendulum built from a computer mouse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gintautas, Vadas; Hubler, Alfred

Lessons and homework problems involving a pendulum are often a big part of introductory physics classes and laboratory courses from high school to undergraduate levels. Although laboratory equipment for pendulum experiments is commercially available, it is often expensive and may not be affordable for teachers on fixed budgets, particularly in developing countries. We present a low-cost, easy-to-build rotary sensor pendulum using the existing hardware in a ball-type computer mouse. We demonstrate how this apparatus may be used to measure both the frequency and coefficient of damping of a simple physical pendulum. This easily constructed laboratory equipment makes it possible formore » all students to have hands-on experience with one of the most important simple physical systems.« less

Translation of time-reversal violation in the neutral K-meson system into a table-top mechanical system

NASA Astrophysics Data System (ADS)

Reiser, Andreas; Schubert, Klaus R.; Stiewe, Jürgen

2012-08-01

Weak interactions break time-reversal (T) symmetry in the two-state system of neutral K-mesons. We present and discuss a two-state mechanical system, i.e. a Foucault-type pendulum on a rotating table, for a full representation of {K^0}{{\\overlineK}{}^0} transitions by the pendulum motions including T violation. The pendulum moves with two different oscillation frequencies and two different magnetic dampings. Its equation of motion is identical to the differential equation for the real part of the CPT-symmetric K-meson wavefunction. The pendulum is able to represent microscopic CP and T violation with CPT symmetry owing to the macroscopic Coriolis force, which breaks the symmetry under reversal-of-motion. Video clips of the pendulum motions are given as supplementary material.

Alternations in burial and exhumation along the Selimiye (Kayabükü) shear zone in the Menderes Massif from detailed garnet pressure-temperature paths

NASA Astrophysics Data System (ADS)

Kelly, E. D.; Atakturk, K. R.; Catlos, E. J.; Lizzadro-McPherson, D. J.; Cemen, I.; Lovera, O. M.

2015-12-01

Pressure-temperature (P-T) paths derived from garnet chemical zoning and supported by thermal modeling record alternating burial and exhumation during Main Menderes Metamorphism in western Turkey. We studied six rocks along the Selimiye (Kayabükü) shear zone, three from the footwall (Çine nappe) and three from the hanging wall (Selimiye nappe). The shear zone bounds the southern Menderes Massif metamorphic core complex and has been suggested to record compression followed by extension. The rocks are lower-amphibolite facies garnet-bearing metapelites with nearly identical mineral suites. Retrograde overprinting hinders classical thermobarometry; to overcome this, preserved chemical zoning in garnet combined with a G-minimization approach was used to construct detailed P-T paths (e.g., 50 points in some paths). During continuous temperature increase, the Çine nappe paths show increasing, decreasing, and then increasing pressure (an N-shaped path) ending at 7-8 kbar and ~565-590 °C. The Selimiye nappe paths show a single increase in P-T ending at ~7.3 kbar and ~580 °C. Similar bulk-rock compositions in all samples and the separation by the shear zone suggest that garnets grew during distinct events in each nappe. The timing of garnet growth, and thus the P-T paths, is currently undetermined, as monazite inclusions in garnet appear secondary and complicated by excess common Pb. The Çine nappe N-shaped path describes alternations in burial and exhumation, possibly due to thrust motion along the shear zone. To demonstrate the physical plausibility of the P-T paths, a 2-D finite difference solution to the diffusion-advection equation was applied. The results of the thermal modeling suggest that thrusting, denudation, and renewed thrusting would produce similar changes in P-T to the N-shaped path. Thus, the Çine nappe N-shaped P-T path appears to record a gap in thrust motion along the Selimiye (Kayabükü) shear zone prior to ultimate unroofing of the massif.

What Makes the Foucault Pendulum Move among the Stars?

ERIC Educational Resources Information Center

Phillips, Norman

2004-01-01

Foucault's pendulum exhibition in 1851 occurred in an era now known by development of the theorems of Coriolis and the formulation of dynamical meteorology by Ferrel. Yet today the behavior of the pendulum is often misunderstood. The existence of a horizontal component of Newtonian gravitation is essential for understanding the behavior with…

49 CFR 572.189 - Instrumentation and test conditions.

Code of Federal Regulations, 2014 CFR

2014-10-01

.... The sum mass of the attachments and 1/3 cable mass must not exceed 5 percent of the total pendulum... filtered CFC 180; (3)Neck and lumbar spine pendulum accelerations—Digitally filtered CFC 60; (4) Pelvis... 180. (j)(1) Filter the pendulum acceleration data using a SAE J211 CFC 60 filter. (2) Determine the...

49 CFR 572.189 - Instrumentation and test conditions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... mass of the attachments and 1/3 cable mass must not exceed 5 percent of the total pendulum mass. No... lumbar spine pendulum accelerations—Digitally filtered CFC 60; (4) Pelvis, shoulder, thorax without arm...—Digitally filtered at CFC 600; (6) Thorax deflection—Digitally filtered CFC 180. (j)(1) Filter the pendulum...

49 CFR 572.33 - Neck.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (b) of this section, on a rigid pendulum as shown in Figure 22 so that the head's midsagittal plane is vertical and coincides with the plane of motion of the pendulum's longitudinal axis. ER02JN11.011 (4) Release the pendulum and allow it to fall freely from a height such that the tangential velocity...

49 CFR 572.189 - Instrumentation and test conditions.

Code of Federal Regulations, 2013 CFR

2013-10-01

.... The sum mass of the attachments and 1/3 cable mass must not exceed 5 percent of the total pendulum... filtered CFC 180; (3)Neck and lumbar spine pendulum accelerations—Digitally filtered CFC 60; (4) Pelvis... 180. (j)(1) Filter the pendulum acceleration data using a SAE J211 CFC 60 filter. (2) Determine the...

49 CFR 572.35 - Limbs.

Code of Federal Regulations, 2014 CFR

2014-10-01

... in accordance with paragraph (b)(2) of this section, at 6.9 ft/sec ±0.10 ft/sec by the pendulum defined in § 572.36(b), the peak knee impact force, which is a product of pendulum mass and acceleration... the femur load cell simulator. (v) Guide the pendulum so that there is no significant lateral...

49 CFR 572.33 - Neck.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (b) of this section, on a rigid pendulum as shown in Figure 22 so that the head's midsagittal plane is vertical and coincides with the plane of motion of the pendulum's longitudinal axis. EC01AU91.165 (4) Release the pendulum and allow it to fall freely from a height such that the tangential velocity...

49 CFR 572.35 - Limbs.

Code of Federal Regulations, 2013 CFR

2013-10-01

... in accordance with paragraph (b)(2) of this section, at 6.9 ft/sec ±0.10 ft/sec by the pendulum defined in § 572.36(b), the peak knee impact force, which is a product of pendulum mass and acceleration... the femur load cell simulator. (v) Guide the pendulum so that there is no significant lateral...

49 CFR 572.189 - Instrumentation and test conditions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... mass of the attachments and 1/3 cable mass must not exceed 5 percent of the total pendulum mass. No... lumbar spine pendulum accelerations—Digitally filtered CFC 60; (4) Pelvis, shoulder, thorax without arm...—Digitally filtered at CFC 600; (6) Thorax deflection—Digitally filtered CFC 180. (j)(1) Filter the pendulum...

49 CFR 572.33 - Neck.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (b) of this section, on a rigid pendulum as shown in Figure 22 so that the head's midsagittal plane is vertical and coincides with the plane of motion of the pendulum's longitudinal axis. ER02JN11.011 (4) Release the pendulum and allow it to fall freely from a height such that the tangential velocity...

49 CFR 572.35 - Limbs.

Code of Federal Regulations, 2012 CFR

2012-10-01

... in accordance with paragraph (b)(2) of this section, at 6.9 ft/sec ±0.10 ft/sec by the pendulum defined in § 572.36(b), the peak knee impact force, which is a product of pendulum mass and acceleration... the femur load cell simulator. (v) Guide the pendulum so that there is no significant lateral...

49 CFR 572.33 - Neck.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (b) of this section, on a rigid pendulum as shown in Figure 22 so that the head's midsagittal plane is vertical and coincides with the plane of motion of the pendulum's longitudinal axis. EC01AU91.165 (4) Release the pendulum and allow it to fall freely from a height such that the tangential velocity...

49 CFR 572.183 - Neck assembly.

Code of Federal Regulations, 2013 CFR

2013-10-01

... subpart E pendulum test fixture as shown in Figure U2-A in appendix A to this subpart, so that the... pendulum longitudinal centerline shown in Figure U2-A. Torque the half-spherical screws (175-2004) located... equivalent; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact...

49 CFR 572.183 - Neck assembly.

Code of Federal Regulations, 2012 CFR

2012-10-01

... subpart E pendulum test fixture as shown in Figure U2-A in appendix A to this subpart, so that the... pendulum longitudinal centerline shown in Figure U2-A. Torque the half-spherical screws (175-2004) located... equivalent; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact...

49 CFR 572.189 - Instrumentation and test conditions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... mass of the attachments and 1/3 cable mass must not exceed 5 percent of the total pendulum mass. No... lumbar spine pendulum accelerations—Digitally filtered CFC 60; (4) Pelvis, shoulder, thorax without arm...—Digitally filtered at CFC 600; (6) Thorax deflection—Digitally filtered CFC 180. (j)(1) Filter the pendulum...

Analysis of the Pendular and Pitch Motions of a Driven Three-Dimensional Pendulum

ERIC Educational Resources Information Center

Findley, T.; Yoshida, S.; Norwood, D. P.

2007-01-01

A three-dimensional pendulum, modelled after the Laser Interferometer Gravitational-Wave Observatory's suspended optics, was constructed to investigate the pendulum's dynamics due to suspension point motion. In particular, we were interested in studying the pendular-pitch energy coupling. Determination of the pendular's Q value (the quality factor…

Explicit Analytical Solution of a Pendulum with Periodically Varying Length

ERIC Educational Resources Information Center

Yang, Tianzhi; Fang, Bo; Li, Song; Huang, Wenhu

2010-01-01

A pendulum with periodically varying length is an interesting physical system. It has been studied by some researchers using traditional perturbation methods (for example, the averaging method). But due to the limitation of the conventional perturbation methods, the solutions are not valid for long-term prediction of the pendulum. In this paper,…

49 CFR 572.183 - Neck assembly.

Code of Federal Regulations, 2010 CFR

2010-10-01

... subpart E pendulum test fixture as shown in Figure U2-A in appendix A to this subpart, so that the... pendulum longitudinal centerline shown in Figure U2-A. Torque the half-spherical screws (175-2004) located... equivalent; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact...

49 CFR 572.35 - Limbs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... in accordance with paragraph (b)(2) of this section, at 6.9 ft/sec ±0.10 ft/sec by the pendulum defined in § 572.36(b), the peak knee impact force, which is a product of pendulum mass and acceleration... the femur load cell simulator. (v) Guide the pendulum so that there is no significant lateral...

The Doppler Pendulum Experiment

ERIC Educational Resources Information Center

Lee, C. K.; Wong, H. K.

2011-01-01

An experiment to verify the Doppler effect of sound waves is described. An ultrasonic source is mounted at the end of a simple pendulum. As the pendulum swings, the rapid change of frequency can be recorded by a stationary receiver using a simple frequency-to-voltage converter. The experimental results are in close agreement with the Doppler…

49 CFR 572.183 - Neck assembly.

Code of Federal Regulations, 2011 CFR

2011-10-01

... subpart E pendulum test fixture as shown in Figure U2-A in appendix A to this subpart, so that the... pendulum longitudinal centerline shown in Figure U2-A. Torque the half-spherical screws (175-2004) located... equivalent; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact...

Steady States of the Parametric Rotator and Pendulum

ERIC Educational Resources Information Center

Bouzas, Antonio O.

2010-01-01

We discuss several steady-state rotation and oscillation modes of the planar parametric rotator and pendulum with damping. We consider a general elliptic trajectory of the suspension point for both rotator and pendulum, for the latter at an arbitrary angle with gravity, with linear and circular trajectories as particular cases. We treat the…

49 CFR 572.35 - Limbs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... in accordance with paragraph (b)(2) of this section, at 6.9 ft/sec ±0.10 ft/sec by the pendulum defined in § 572.36(b), the peak knee impact force, which is a product of pendulum mass and acceleration... the femur load cell simulator. (v) Guide the pendulum so that there is no significant lateral...

49 CFR 572.33 - Neck.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (b) of this section, on a rigid pendulum as shown in Figure 22 so that the head's midsagittal plane is vertical and coincides with the plane of motion of the pendulum's longitudinal axis. ER02JN11.011 (4) Release the pendulum and allow it to fall freely from a height such that the tangential velocity...

49 CFR 572.183 - Neck assembly.

Code of Federal Regulations, 2014 CFR

2014-10-01

... subpart E pendulum test fixture as shown in Figure U2-A in appendix A to this subpart, so that the... pendulum longitudinal centerline shown in Figure U2-A. Torque the half-spherical screws (175-2004) located... equivalent; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact...

A Simple, Low-Cost, Data-Logging Pendulum Built from a Computer Mouse

ERIC Educational Resources Information Center

Gintautas, Vadas; Hubler, Alfred

2009-01-01

Lessons and homework problems involving a pendulum are often a big part of introductory physics classes and laboratory courses from high school to undergraduate levels. Although laboratory equipment for pendulum experiments is commercially available, it is often expensive and may not be affordable for teachers on fixed budgets, particularly in…

The Reproduction of Scientific Understanding about Pendulum Motion in the Public

ERIC Educational Resources Information Center

Manabu, Sumida

2004-01-01

This paper describes life-span development of understanding about pendulum motion and effects of school science. The subjects were 2,766 people ranging from kindergartners up to 88 years senior citizens. The conflict and consensus between children and their parent's understanding of pendulum motion were also analyzed. The kindergartner's…

The Multiple Pendulum Problem via Maple[R

ERIC Educational Resources Information Center

Salisbury, K. L.; Knight, D. G.

2002-01-01

The way in which computer algebra systems, such as Maple, have made the study of physical problems of some considerable complexity accessible to mathematicians and scientists with modest computational skills is illustrated by solving the multiple pendulum problem. A solution is obtained for four pendulums with no restriction on the size of the…

Idealisation and Galileo's Pendulum Discoveries: Historical, Philosophical and Pedagogical Considerations

ERIC Educational Resources Information Center

Matthews, Michael R.

2004-01-01

Galileo's discovery of the properties of pendulum motion depended on his adoption of the novel methodology of idealisation. Galileo's laws of pendulum motion could not be accepted until the empiricist methodological constraints placed on science by Aristotle, and by common sense, were overturned. As long as scientific claims were judged by how the…

Human Subject Effects on Torsion Pendulum Oscillations: Further Evidence of Mediation by Convection Currents.

PubMed

Hammerschlag, Richard; Linda Baldwin, Ann; Schwartz, Gary E

When a human subject sits beneath a wire mesh, hemispheric torsion pendulum (TP) a rapid-onset series of oscillations at frequencies both higher and lower than the fundamental frequency of the TP have been consistently observed. This study was designed to replicate and extend prior findings that suggest the human subject effect on TP behavior is due to subject-generated, heat-induced convection currents. Effects on pendulum behavior were tested after draping an aluminized "space blanket" over the subject and by replacing the subject with a thermal mattress pad shaped to approximate the human form. Experiments were performed in a basic science university research laboratory. Real-time recordings and Fast Fourier Transform frequency spectra of pendulum oscillatory movement. The space blanket blocked, while the mattress pad mimicked, the human subject induced complex array of pendulum oscillations. Our findings support and strengthen previous results that suggest the effects of human subjects on behavior of a torsion pendulum are mediated by body-heat-induced air convection rather than an unknown type of biofield. Copyright © 2016 Elsevier Inc. All rights reserved.

Analytical study of the critical behavior of the nonlinear pendulum

NASA Astrophysics Data System (ADS)

Lima, F. M. S.

2010-11-01

The dynamics of a simple pendulum consisting of a small bob and a massless rigid rod has three possible regimes depending on its total energy E: Oscillatory (when E is not enough for the pendulum to reach the top position), "perpetual ascent" when E is exactly the energy needed to reach the top, and nonoscillatory for greater energies. In the latter regime, the pendulum rotates periodically without velocity inversions. In contrast to the oscillatory regime, for which an exact analytic solution is known, the other two regimes are usually studied by solving the equation of motion numerically. By applying conservation of energy, I derive exact analytical solutions to both the perpetual ascent and nonoscillatory regimes and an exact expression for the pendulum period in the nonoscillatory regime. Based on Cromer's approximation for the large-angle pendulum period, I find a simple approximate expression for the decrease of the period with the initial velocity in the nonoscillatory regime, valid near the critical velocity. This expression is used to study the critical slowing down, which is observed near the transition between the oscillatory and nonoscillatory regimes.

Correlation of Coseismic Velocity and Static Volumetric Strain Changes Induced by the 2010 Mw6.3 Jiasian Earthquake under the Southern Taiwan Orogenic Belt

NASA Astrophysics Data System (ADS)

Wu, S. M.; Hung, S. H.

2015-12-01

Earthquake-induced temporal changes in seismic velocity of the earth's crust have been demonstrated to be monitored effectively by the time-lapse shifts of coda waves recently. Velocity drop during the coseismic rupture has been explicitly observed in proximity to the epicenters of large earthquakes with different styles of faulting. The origin of such sudden perturbation in crustal properties is closely related to the damage and/or volumetric strain change influenced by seismic slip distribution. In this study, we apply a coda wave interferometry method to investigate potential velocity change in both space and time related to the moderate-sized (Mw6.3) 2010 Jiasian earthquake, which nucleated deeply in the crust (~23 km), ruptured and terminated around the depth of 10 km along a previously unidentified blind thrust fault near the lithotectonic boundary of the southern Taiwan orogenic belt. To decipher the surface and crustal response to this relatively deep rupture, we first measure relative time-lapse changes of coda between different short-term time frames spanning one year covering the pre- and post-seismic stages by using the Moving Window Cross Spectral Method. Rather than determining temporal velocity variations based on a long-term reference stack, we conduct a Bayesian least-squares inversion to obtain the optimal estimates by minimizing the inconsistency between the relative time-lapse shifts of individual short-term stacks. The results show the statistically significant velocity reduction immediately after the mainshock, which is most pronounced at the pairs with the interstation paths traversing through the hanging-wall block of the ruptured fault. The sensitivity of surface wave coda arrivals mainly in the periods of 3-5 s to shear wave speed perturbation is confined within the depth of 10 km, where the crust mostly experienced extensional strain changes induced by the slip distribution from the finite-fault model. Compared with coseismic slip distribution from GPS data and finite-fault inversion, peak ground velocity, and static volumetric strain field following the earthquake, the velocity decrease observed in the hanging wall side of the shallow crust is most likely attributed to pervasive dilatational strain changes induced by the slip rupture on the underlying blind thrust.

Direct Observations of In Situ Stress State in a 3 Kilometer Deep Borehole in the Upper Plate, Nankai Trough Subduction Zone: IODP Site C0002

NASA Astrophysics Data System (ADS)

Tobin, H. J.; Saffer, D. M.; Castillo, D. A.; Hirose, T.

2016-12-01

During IODP Expedition 348, borehole C0002F/N/P was advanced to a depth of 3058 m below the seafloor (mbsf) into the inner forearc accretionary wedge of the Nankai subduction zone (SW Japan), now the deepest scientific drilling ever into the ocean floor. The goals were to investigate the physical properties, structure, and state of stress deep within the hanging wall of a seismogenic subduction plate boundary. Mud pressure and gas monitoring, injection tests, leak-off tests (LOT), logging-while-drilling (LWD) measurements, and observations of mud losses and hole conditions provide both direct and indirect information about in situ pore pressure and stress state. The LOTs show that the minimum principal stress is consistently less than the vertical stress defined by the overburden, ruling out a thrust faulting stress state throughout the drilled section, and define a nearly linear gradient in Shmin from the seafloor to the base of the hole. Observations of mud loss and the lack of observed gas shows indicate that formation pore fluid pressure is not significantly (< 10 MPa) greater than hydrostatic. The maximum horizontal stress, estimated from borehole breakout width and pressure spikes during pack-off events, is close in magnitude to the vertical stress. Therefore the accretionary prism lies in either a normal or strike-slip faulting regime, or is transitional between the two, from 1 to 3 km depth. At 3002 mbsf we estimate that the effective stresses are: Sv' = 33 MPa; SHmax' = 25-36 MPa; and Shmin' = 18.5-21 MPa. Differential stresses are therefore low, on the order of 10-12 MPa, in the hanging wall of the subduction thrust. We conclude that (1) the inner wedge is not critically stressed in horizontal compression; (2) basal traction along the megathrust must be low in order to permit concurrent locking of the fault and low differential stresses deep within the upper plate; and (3) although low differential stresses may persist down to the plate boundary at 5000 mbsf, the maximum horizontal stress SHmax must transition to become greater than the vertical stress, either spatially below the base of the borehole, or temporally leading up to megathrust fault rupture, in order to drive slip on the megathrust.

Characteristic Features of Hanging: A Study in Rural District of Central India.

PubMed

Ambade, Vipul Namdeorao; Kolpe, Dayanand; Tumram, Nilesh; Meshram, Satin; Pawar, Mohan; Kukde, Hemant

2015-09-01

The ligature mark is the most relevant feature of hanging. This study was undertaken with a view to determine the characteristic features of hanging and its association with ligature material or mode of suspension. Of a total medicolegal deaths reported at an Apex Medical Centre, hanging was noted in 4.1% cases, all suicidal with mortality rate of 1.5 per 100,000 population per year. The hanging was complete in 67.7% with nylon rope as the commonest type of ligature material used for ligation. The hanging mark was usually single, situated above thyroid cartilage, incomplete, prominent, and directed toward nape of neck. The mark of dribbling of saliva was seen in 11.8% cases. Facial congestion, petechial hemorrhage, and cyanosis were significantly seen in partial hanging. Though occasionally reported, the argent line was noted in 78.7% hanging deaths with neck muscle hemorrhage in 23.6% cases. Fracture of neck structure was predominant in complete hanging. © 2015 American Academy of Forensic Sciences.

Note: A 1-m Foucault pendulum rolling on a ball.

PubMed

Salva, H R; Benavides, R E; Venturino, J A; Cuscueta, D J; Ghilarducci, A A

2013-10-01

We have built a short Foucault pendulum of 1-m length. The aim of this work was to increase the sensitivity to elliptical trajectories from other longer pendula. The design was a semi-rigid pendulum that rolls over a small ball. The measurements of the movements (azimuth and elliptical trajectory) were done by an optical method. The resulting pendulum works in a medium satisfactory way due to problems of the correct choice of the mass of the bob together with the diameter of the supporting ball. It is also important to keep the rolling surface very clean.

Comparison of strain rates of dart impacted plaques and pendulum impacted bumpers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scammell, K.L.

1987-01-01

The difference in strain rates prevailing during pendulum impact of bumpers versus high speed dart impact of plaques was investigated. Uni-axial strain gages were applied to the tension side of the plaques and bumpers directly opposite the point of impact. The plaques were impacted with an instrumented high rate dart impact tester and the bumpers impacted with a full scale bumper pendulum impact tester. Theoretical calculations and actual strain rate data support the conclusion that the strain rate of a plaque during dart impact significantly exceeds that of bumper strain rate during pendulum impact.

Hang cleans and hang snatches produce similar improvements in female collegiate athletes

PubMed Central

Ayers, JL; DeBeliso, M; Sevene, TG

2016-01-01

Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed. PMID:27601779

Duodenoscope hang time does not correlate with risk of bacterial contamination.

PubMed

Heroux, Riley; Sheppard, Michelle; Wright, Sharon B; Sawhney, Mandeep; Hirsch, Elizabeth B; Kalaidjian, Robin; Snyder, Graham M

2017-04-01

Current professional guidelines recommend a maximum hang time for reprocessed duodenoscopes of 5-14 days. We sought to study the association between hang time and risk of duodenoscope contamination. We analyzed cultures of the elevator mechanism and working channel collected in a highly standardized fashion just before duodenoscope use. Hang time was calculated as the time from reprocessing to duodenoscope sampling. The relationship between hang time and duodenoscope contamination was estimated using a calculated correlation coefficient between hang time in days and degree of contamination on the elevator mechanism and working channel. The 18 study duodenoscopes were cultured 531 times, including 465 (87.6%) in the analysis dataset. Hang time ranged from 0.07-39.93 days, including 34 (7.3%) with hang time ≥7.00 days. Twelve cultures (2.6%) demonstrated elevator mechanism and/or working channel contamination. The correlation coefficients for hang time and degree of duodenoscope contamination were very small and not statistically significant (-0.0090 [P = .85] for elevator mechanism and -0.0002 [P = 1.00] for working channel). Odds ratios for hang time (dichotomized at ≥7.00 days) and elevator mechanism and/or working channel contamination were not significant. We did not find a significant association between hang time and risk of duodenoscope contamination. Future guidelines should consider a recommendation of no limit for hang time. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Hang cleans and hang snatches produce similar improvements in female collegiate athletes.

PubMed

Ayers, J L; DeBeliso, M; Sevene, T G; Adams, K J

2016-09-01

Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed.

Thermoluminesence Properties and Ages along the Stony Creek, Hanging Wall of Alpine Fault, New Zealand

NASA Astrophysics Data System (ADS)

Nishikawa, O.; Theeraporn, C.; Takashima, I.; Shigematsu, N.; Little, T. A.; Boulton, C. J.

2015-12-01

The Alpine Fault, New Zealand is an oblique slip thrust with significantly high slip rate, and its dip-slip component causes the rapid uplift of the Southern Alps and the extremely high geothermal gradient in it. Thermoluminescence (TL) dating is a method using the phenomenon that energy accumulated in the crystal from radiation of surrounding radioactive elements is reemitted in the form of light when heating the minerals. This method covers a wide range of age from 1,000 to 1,000,000 years, and has relatively low reset temperature for the accumulation of radiation dose. Therefore, TL dating is a feasible geochronometry for the reconstruction of the thermal history of the area with very high uplifting rate. In order to determine uplifting rates and their distribution in the Southern Alps adjacent to the Alpine fault, ten rock samples were collected for TL dating in the distance 1 km from main fault plane along the Stony Creek. All the samples commonly include quartz veins which are folded tightly or in isoclinal form parallel to the foliations. TL dating was performed using quartz grains separated from host rock. A widely ranging TL ages are obtained from the hanging wall of the fault. The rocks within 600m from present shear zone yield ages ranging from 55.2 ka to 88.8 ka, showing older ages with distance from shear zone. Within 600 m to 900 m from the fault, relatively younger ages, 54.7 to 34.4 ka are obtained. Assuming the thermal gradient of 10 °C /100 m and exhumation rate of 10 m / kyr, the zeroing depth and temperature of TL signals is estimated from 350 to 900 m and from 45 to 100 °C, respectively. The range of TL ages is very large amounted to 50,000 years in the narrow zone. This may be responsible for the variety of TL zeroing temperatures in the hanging wall rocks rather than disturbance of thermal structure and/or inhomogeneity of uplifting rate in this area. Annealing tests are necessary to clarify the real properties of TL for each sample tested.

A Comprehensive Analytical Solution of the Nonlinear Pendulum

ERIC Educational Resources Information Center

Ochs, Karlheinz

2011-01-01

In this paper, an analytical solution for the differential equation of the simple but nonlinear pendulum is derived. This solution is valid for any time and is not limited to any special initial instance or initial values. Moreover, this solution holds if the pendulum swings over or not. The method of approach is based on Jacobi elliptic functions…

49 CFR 581.5 - Requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the damage criteria of §§ 581.5(c)(1) through 581.5(c)(9) when impacted by a pendulum-type test device... of 1.5 m.p.h., and when impacted by a pendulum-type test device in accordance with the procedures of... original contours 30 minutes after completion of each pendulum and barrier impact, except where such damage...

49 CFR 581.5 - Requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the damage criteria of §§ 581.5(c)(1) through 581.5(c)(9) when impacted by a pendulum-type test device... of 1.5 m.p.h., and when impacted by a pendulum-type test device in accordance with the procedures of... original contours 30 minutes after completion of each pendulum and barrier impact, except where such damage...

Oscillations of a Simple Pendulum with Extremely Large Amplitudes

ERIC Educational Resources Information Center

Butikov, Eugene I.

2012-01-01

Large oscillations of a simple rigid pendulum with amplitudes close to 180[degrees] are treated on the basis of a physically justified approach in which the cycle of oscillation is divided into several stages. The major part of the almost closed circular path of the pendulum is approximated by the limiting motion, while the motion in the vicinity…

49 CFR 581.5 - Requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the damage criteria of §§ 581.5(c)(1) through 581.5(c)(9) when impacted by a pendulum-type test device... of 1.5 m.p.h., and when impacted by a pendulum-type test device in accordance with the procedures of... original contours 30 minutes after completion of each pendulum and barrier impact, except where such damage...

Measurement of Gravitational Acceleration Using a Computer Microphone Port

ERIC Educational Resources Information Center

Khairurrijal; Eko Widiatmoko; Srigutomo, Wahyu; Kurniasih, Neny

2012-01-01

A method has been developed to measure the swing period of a simple pendulum automatically. The pendulum position is converted into a signal frequency by employing a simple electronic circuit that detects the intensity of infrared light reflected by the pendulum. The signal produced by the electronic circuit is sent to the microphone port and…

Einstein versus the Simple Pendulum Formula: Does Gravity Slow All Clocks?

ERIC Educational Resources Information Center

Puri, Avinash

2015-01-01

According to the Newtonian formula for a simple pendulum, the period of a pendulum is inversely proportional to the square root of "g", the gravitational field strength. Einstein's theory of general relativity leads to the result that time slows down where gravity is intense. The two claims look contradictory and can muddle student and…

Maple[R] Version of the "Indian Rope Trick". Classroom Notes

ERIC Educational Resources Information Center

Knight, D. G.

2004-01-01

If the point of suspension of a multiple pendulum is suitably oscillated then the pendulum can remain in motion in an upside-down position. Since such pendulums can model flexible materials, this inverted motion is sometimes referred to as an 'Indian rope trick'. Despite the complexity of the governing differential equations, this rope trick can…

A Laboratory Experiment on Coupled Non-Identical Pendulums

ERIC Educational Resources Information Center

Li, Ang; Zeng, Jingyi; Yang, Hujiang; Xiao, Jinghua

2011-01-01

In this paper, coupled pendulums with different lengths are studied. Through steel magnets, each pendulum is coupled with others, and a stepping motor is used to drive the whole system. To record the data automatically, we designed a data acquisition system with a CCD camera connected to a computer. The coupled system shows in-phase, locked-phase…

49 CFR 581.5 - Requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the damage criteria of §§ 581.5(c)(1) through 581.5(c)(9) when impacted by a pendulum-type test device... of 1.5 m.p.h., and when impacted by a pendulum-type test device in accordance with the procedures of... original contours 30 minutes after completion of each pendulum and barrier impact, except where such damage...

49 CFR 581.5 - Requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the damage criteria of §§ 581.5(c)(1) through 581.5(c)(9) when impacted by a pendulum-type test device... of 1.5 m.p.h., and when impacted by a pendulum-type test device in accordance with the procedures of... original contours 30 minutes after completion of each pendulum and barrier impact, except where such damage...

An Apparatus to Demonstrate Linear and Nonlinear Oscillations of a Pendulum

ERIC Educational Resources Information Center

Mayer, V. V.; Varaksina, E. I.

2016-01-01

A physical pendulum with a magnetic load is proposed for comparison of linear and nonlinear oscillations. The magnetic load is repelled by permanent magnets which are disposed symmetrically relative to the load. It is established that positions of the pendulum and the magnets determine the dependence of restoring force on displacement of the load.…

Chemistry and the Pendulum--What Have They to Do with Each Other?

ERIC Educational Resources Information Center

De Berg, K. C.

2006-01-01

Physicists have known for some time that pendulum motion is a useful analogy for other physical processes. Chemists have played with the idea from time to time but the strength of the analogy between pendulum motion and chemical processes has only received prominent published recognition since about 1980, although there are details of the analogy…

Extending the Range for Force Calibration in Magnetic Tweezers

PubMed Central

Daldrop, Peter; Brutzer, Hergen; Huhle, Alexander; Kauert, Dominik J.; Seidel, Ralf

2015-01-01

Magnetic tweezers are a wide-spread tool used to study the mechanics and the function of a large variety of biomolecules and biomolecular machines. This tool uses a magnetic particle and a strong magnetic field gradient to apply defined forces to the molecule of interest. Forces are typically quantified by analyzing the lateral fluctuations of the biomolecule-tethered particle in the direction perpendicular to the applied force. Since the magnetic field pins the anisotropy axis of the particle, the lateral fluctuations follow the geometry of a pendulum with a short pendulum length along and a long pendulum length perpendicular to the field lines. Typically, the short pendulum geometry is used for force calibration by power-spectral-density (PSD) analysis, because the movement of the bead in this direction can be approximated by a simple translational motion. Here, we provide a detailed analysis of the fluctuations according to the long pendulum geometry and show that for this direction, both the translational and the rotational motions of the particle have to be considered. We provide analytical formulas for the PSD of this coupled system that agree well with PSDs obtained in experiments and simulations and that finally allow a faithful quantification of the magnetic force for the long pendulum geometry. We furthermore demonstrate that this methodology allows the calibration of much larger forces than the short pendulum geometry in a tether-length-dependent manner. In addition, the accuracy of determination of the absolute force is improved. Our force calibration based on the long pendulum geometry will facilitate high-resolution magnetic-tweezers experiments that rely on short molecules and large forces, as well as highly parallelized measurements that use low frame rates. PMID:25992733

Oscillators: Old and new perspectives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharjee, Jayanta K.; Roy, Jyotirmoy

We consider some of the well known oscillators in literature which are known to exhibit interesting effects of nonlinearity. We review the Lindstedt-Poincare technique for dealing with with the nonlinear effects and then go on to introduce the relevance of the renormalization group for the oscillator following the pioneering work of Chen et al. It is pointed out that the traditional Lindstedt-Poincare and the renormalization group techniques have operational connections. We use this to find an unexpected mode softening in the double pendulum. This mode softening prompted us to look for chaos in the double pendulum at low energies-energies thatmore » are just sufficient to allow the outer pendulum to rotate (the double pendulum is known to be chaotic at high energies-energies that are greater than that needed to make both pendulums to rotate). The emergence of the chaos is strongly dependent on initial conditions.« less

Efficiency of SparkJet

NASA Technical Reports Server (NTRS)

Golbabaei-Asl, M.; Knight, D.; Wilkinson, S.

2013-01-01

The thermal efficiency of a SparkJet is evaluated by measuring the impulse response of a pendulum subject to a single spark discharge. The SparkJet is attached to the end of a pendulum. A laser displacement sensor is used to measure the displacement of the pendulum upon discharge. The pendulum motion is a function of the fraction of the discharge energy that is channeled into the heating of the gas (i.e., increasing the translational-rotational temperature). A theoretical perfect gas model is used to estimate the portion of the energy from the heated gas that results in equivalent pendulum displacement as in the experiment. The earlier results from multiple runs for different capacitances of C = 3, 5, 10, 20, and 40(micro)F demonstrate that the thermal efficiency decreases with higher capacitive discharges.1 In the current paper, results from additional run cases have been included and confirm the previous results

Study of endolaryngeal structures by videolaryngoscopy after hanging: a new approach to understanding the physiopathogenesis.

PubMed

Duband, S; Timoshenko, A P; Mohammedi, R; Prades, J-M; Barral, F-G; Debout, M; Péoc'h, M

2009-11-20

To evaluate laryngoscopic findings in hanging cases and to compare them with magnetic resonance imaging (MRI) and forensic autopsy results. Postmortem nasolaryngofibroscopy and MRI of five people who died from hanging were performed. Three people who died from other causes than hanging were also examined with a flexible laryngofibroscope. The results were compared with injuries discovered during forensic autopsy. In all five hanging cases, laryngofibroscopic investigation showed a vocal fold position in complete adduction confirmed by MRI. This position did not seem to be influenced by the intensity of the forces applied to neck or postmortem delay and cadaveric phenomena. The vocal cords of the three non-hanging deceased were found in the intermediate position. These findings could suggest that pressure applied to the cervical nervous and cartilaginous structures or their elongation during hanging could lead to closure of the glottis with vocal cord adduction maintained after death. Laryngofibroscopic examination in hanging cases could be very useful in confirming the vital character of the hanging and understanding asphyxial phenomena in incomplete suspension without laryngeal crush.

The Pendulum in the 21st Century-Relic or Trendsetter

ERIC Educational Resources Information Center

Peters, Randall D.

2004-01-01

When identifying instruments that have had great influence on the history of physics, none comes to mind more quickly than the pendulum. Though first treated scientifically by Galileo in the 16th century, and in some respects nearly "dead" by the middle of the 20th century; the pendulum experienced "rebirth" by becoming an archetype of chaos. With…

Analysis of Pendulum Period with an iPod Touch/iPhone

ERIC Educational Resources Information Center

Briggle, Justin

2013-01-01

We describe the use of Apple's iPod touch/iPhone, acting as the pendulum bob, as a means of measuring pendulum period, making use of the device's three-axis digital accelerometer and the freely available SPARKvue app from PASCO scientific. The method can be readily incorporated into an introductory physics laboratory experiment.…

On the Stable Limit Cycle of a Weight-Driven Pendulum Clock

ERIC Educational Resources Information Center

Llibre, J; Teixeira, M. A.

2010-01-01

In a recent paper (Denny 2002 Eur. J. Phys. 23 449-58), entitled "The pendulum clock: a venerable dynamical system", Denny showed that in a first approximation the steady-state motion of a weight-driven pendulum clock is shown to be a stable limit cycle. He placed the problem in a historical context and obtained an approximate solution using the…

49 CFR 572.187 - Lumbar spine.

Code of Federal Regulations, 2013 CFR

2013-10-01

...-headform assembly to the Part 572 pendulum test fixture per procedure in § 572.183(b)(2) and as shown in... assembly (175-5506) to 50 ±5 in-lb; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact velocity of 6.05 ±0.1 m/s measured at the center of the pendulum...

49 CFR 572.187 - Lumbar spine.

Code of Federal Regulations, 2012 CFR

2012-10-01

...-headform assembly to the Part 572 pendulum test fixture per procedure in § 572.183(b)(2) and as shown in... assembly (175-5506) to 50 ±5 in-lb; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact velocity of 6.05 ±0.1 m/s measured at the center of the pendulum...

49 CFR 572.187 - Lumbar spine.

Code of Federal Regulations, 2011 CFR

2011-10-01

...-headform assembly to the Part 572 pendulum test fixture per procedure in § 572.183(b)(2) and as shown in... assembly (175-5506) to 50 ± 5 in-lb; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact velocity of 6.05 ±0.1 m/s measured at the center of the pendulum...

The Bravais Pendulum: The Distinct Charm of an Almost Forgotten Experiment

ERIC Educational Resources Information Center

Babovic, V. M.; Mekic, S.

2011-01-01

In the year 1851 in Paris, the apparent change of the plane of oscillation of a linear pendulum was observed by Leon Foucault. In the same year, at the same place, the unequal duration of the oscillations of a right- and left-handed conical pendulum was observed by Bravais. Today, the Foucault pendula are common at universities, the Bravais…

49 CFR 572.187 - Lumbar spine.

Code of Federal Regulations, 2010 CFR

2010-10-01

...-headform assembly to the Part 572 pendulum test fixture per procedure in § 572.183(b)(2) and as shown in... assembly (175-5506) to 50 ± 5 in-lb; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact velocity of 6.05 ±0.1 m/s measured at the center of the pendulum...

Approximate Expressions for the Period of a Simple Pendulum Using a Taylor Series Expansion

ERIC Educational Resources Information Center

Belendez, Augusto; Arribas, Enrique; Marquez, Andres; Ortuno, Manuel; Gallego, Sergi

2011-01-01

An approximate scheme for obtaining the period of a simple pendulum for large-amplitude oscillations is analysed and discussed. When students express the exact frequency or the period of a simple pendulum as a function of the oscillation amplitude, and they are told to expand this function in a Taylor series, they always do so using the…

49 CFR 572.187 - Lumbar spine.

Code of Federal Regulations, 2014 CFR

2014-10-01

...-headform assembly to the Part 572 pendulum test fixture per procedure in § 572.183(b)(2) and as shown in... assembly (175-5506) to 50 ±5 in-lb; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact velocity of 6.05 ±0.1 m/s measured at the center of the pendulum...

Experimental Uncertainty Associated with Traveling Wave Excitation

DTIC Science & Technology

2014-09-15

20 2.9 Schematic of the Lumped Model [6] . . . . . . . . . . . . . . . . . . . . . . . 21 2.10 Multiple Coupled Pendulum [7...model to describe the physical system, the authors chose to employ a coupled pendulum model to represent a rotor. This system is shown in Figure 2.10...System mistuning is introduced by altering pendulum lengths. All other system parameters are equal. A linear viscous proportional damping force is

Working Model of a Foucault Pendulum at Intermediate Latitudes

ERIC Educational Resources Information Center

Sears, Francis W.

1969-01-01

Describes a working model of a Foucault pendulum at intermediate latitudes constructed of a steel drill rod with a steel ball attached at one end. The rod makes an angle of 45 degrees with the rotation axis of a horizontal turntable. The vibrating system is the same as that which led Foucault to construct his first gravity pendulum. (LC)

Propagation-invariant beams with quantum pendulum spectra: from Bessel beams to Gaussian beam-beams.

PubMed

Dennis, Mark R; Ring, James D

2013-09-01

We describe a new class of propagation-invariant light beams with Fourier transform given by an eigenfunction of the quantum mechanical pendulum. These beams, whose spectra (restricted to a circle) are doubly periodic Mathieu functions in azimuth, depend on a field strength parameter. When the parameter is zero, pendulum beams are Bessel beams, and as the parameter approaches infinity, they resemble transversely propagating one-dimensional Gaussian wave packets (Gaussian beam-beams). Pendulum beams are the eigenfunctions of an operator that interpolates between the squared angular momentum operator and the linear momentum operator. The analysis reveals connections with Mathieu beams, and insight into the paraxial approximation.

Analysis of the linearity of half periods of the Lorentz pendulum

NASA Astrophysics Data System (ADS)

Wickramasinghe, T.; Ochoa, R.

2005-05-01

We analyze the motion of the Lorentz pendulum, a simple pendulum whose length is changed at a constant rate k. We show both analytically and numerically that the half period Tn, the time between half oscillations as measured from midpoint to midpoint, increases linearly with the oscillation number n such that Tn+1-Tn≈kπ2/2g, where g is the acceleration due to gravity. A video camera is used to record the motion of the oscillating bob of the pendulum and verify the linearity of Tn with oscillation number. The theory and the experiment are suitable for an advanced undergraduate laboratory.

An inexpensive, multipurpose physical pendulum

NASA Astrophysics Data System (ADS)

Schultz, David

2012-10-01

The pendulum is a highly versatile tool for teaching physics. Many special purpose pendula for student experiments have been described.1-4 In this paper, I describe an inexpensive, multipurpose physical pendulum that can function as both a variable gravity and ballistic pendulum. I designed the apparatus for use in a rotational dynamics unit of the AP Physics C mechanics course. The use of a bike wheel hub pivot allows for low-friction, rugged operation that yields results commensurate with those obtained with much more expensive pendula available on the market (typically 500 per unit5), placing these types of experiments within reach of the teacher on a restricted budget.

Orion GN&C Detection and Mitigation of Parachute Pendulosity

NASA Technical Reports Server (NTRS)

Kane, Mark A.; Wacker, Roger

2016-01-01

New techniques being employed by Orion guidance, navigation, and control (GN&C) using a reaction control system (RCS) under parachutes are described. Pendulosity refers to a pendulum-oscillatory mode that can occur during descent under main parachutes and that has been observed during Orion parachute drop tests. The pendulum mode reduces the ability of GN&C to maneuver the suspended vehicle resulting in undesirable increases to structural loads at touchdown. Parachute redesign efforts have been unsuccessful in reducing the pendulous behavior necessitating GN&C mitigation options. An observer has been developed to estimate the pendulum motion as well as the underlying wind velocity vector. Using this knowledge, the control system maneuvers the vehicle using two separate strategies determined by wind velocity magnitude and pendulum energy thresholds; at high wind velocities the vehicle is aligned with the wind direction and for cases with lower wind velocities and large pendulum amplitudes the vehicle is aligned such that it is perpendicular to the swing plane. Pendulum damping techniques using RCS thrusters are discussed but have not been selected for use onboard the Orion spacecraft. The techniques discussed in this paper will be flown on Exploration Mission 1 (EM-1).

Pendulum Motion in Main Parachute Clusters

NASA Technical Reports Server (NTRS)

Ray, Eric S.; Machin, Ricardo A.

2015-01-01

The coupled dynamics of a cluster of parachutes to a payload are notoriously difficult to predict. Often the payload is designed to be insensitive to the range of attitude and rates that might occur, but spacecraft generally do not have the mass and volume budgeted for this robust of a design. The National Aeronautics and Space Administration (NASA) Orion Capsule Parachute Assembly System (CPAS) implements a cluster of three mains for landing. During testing of the Engineering Development Unit (EDU) design, it was discovered that with a cluster of two mains (a fault tolerance required for human rating) the capsule coupled to the parachute cluster could get into a limit cycle pendulum motion which would exceed the spacecraft landing capability. This pendulum phenomenon could not be predicted with the existing models and simulations. A three phased effort has been undertaken to understand the consequence of the pendulum motion observed, and explore potential design changes that would mitigate this phenomenon. This paper will review the early analysis that was performed of the pendulum motion observed during EDU testing, summarize the analysis ongoing to understand the root cause of the pendulum phenomenon, and discuss the modeling and testing that is being pursued to identify design changes that would mitigate the risk.

World pendulum—a distributed remotely controlled laboratory (RCL) to measure the Earth's gravitational acceleration depending on geographical latitude

NASA Astrophysics Data System (ADS)

Gröber, S.; Vetter, M.; Eckert, B.; Jodl, H.-J.

2007-05-01

We suggest that different string pendulums are positioned at different locations on Earth and measure at each place the gravitational acceleration (accuracy Δg ~ 0.01 m s-2). Each pendulum can be remotely controlled via the internet by a computer located somewhere on Earth. The theoretical part describes the physical origin of this phenomenon g(phiv), that the Earth's effective gravitational acceleration g depends on the angle of latitude phiv. Then, we present all necessary formula to deduce g(phiv) from oscillations of a string pendulum. The technical part explains tips and tricks to realize such an apparatus to measure all necessary values with sufficient accuracy. In addition, we justify the precise dimensions of a physical pendulum such that the formula for a mathematical pendulum is applicable to determine g(phiv) without introducing errors. To conclude, we describe the internet version—the string pendulum as a remotely controlled laboratory. The teaching relevance and educational value will be discussed in detail at the end of this paper including global experimenting, using the internet and communication techniques in teaching and new ways of teaching and learning methods.

Thrust exhumation of the Southern Marginal Zone of the Limpopo Complex in the Neoarchaean: link of distinct high-grade shear zones with DC and IC P-T-t paths

NASA Astrophysics Data System (ADS)

Smit, C. Andre; van Reenen, Dirk D.

2010-05-01

The Limpopo Complex is a ~750km long E-W trending zone of predominantly granulite facies rocks situated between the Archaean Kaapvaal and Zimbabwe cratons of southern Africa. Large ductile shear zones are an integral part of the Limpopo architecture, defining the boundaries between the belt and the adjacent cratons and are interpreted to have been responsible for uplift (exhumation) of over thickened crust during the Neoarchaean [10 and references therein; 1]. The Hout River Shear Zone forms the terrane boundary between the granite-greenstone terrane of the Kaapvaal craton in the south and the high-grade Southern Marginal Zone (SMZ) of the Limpopo Complex in the north. Integrated structural, metamorphic, magmatic and age data collected over a period of more than 30 years provide convincing evidence for a Neoarchean high-grade tectono-metamorphic event that affected the SMZ in the interval ~2.72 - 2.60 Ga [4; 5, 6; 7; 2; 8; 9; 11]. The thrust-controlled exhumation of the SMZ is demonstrated by the convergence of a retrograde P-T path in the hanging wall (SMZ) and a prograde P-T loop in the footwall (Kaapvaal Craton) of the steeply SW-verging Hout River Shear Zone [4; 5]. The coeval ages (~2.69 Ga) of the two contrasting metamorphic histories are indicated by geochronological data [2; 3]. In addition, the establishment of a retrograde isograd and zone of rehydrated granulites in the hanging wall by hydrous CO2-rich fluids derived by dehydration of the low-grade rocks in the footwall provides another convincing link between the two contrasting metamorphic environments [10]. Distinct retrograde P-T paths [4; 6; 8] linked to distinct shear deformational events document evidence for a two-stage post-peak exhumation history of the SMZ: (i) granulites sampled far from the contact with the cool rocks of the Kaapvaal Craton are characterized by P-T paths with two distinct decompression-cooling (DC) stages (DC=>DC paths), (ii) granulites sampled close to this contact are characterized by P-T paths with an inflection that reflects near-isobaric cooling (IC) (DC=>IC paths). The early (2.69-2.664Ga) DC stage (P ~8 kbar, T ~825oC to P ~6.5 kbar, T ~750oC) of exhumation is linked to the transportation of the high-grade rocks up the steep ramp section of the Hout River Shear Zone that controlled their emplacement to upper crustal levels. The later (~2.62-2.6Ga) near-IC stage (P ~6.5kbar, T ~700oC to P ~ 5kbar, T ~500oC) of exhumation is linked to the flat section of SW-verging thrusts that reflect the emplacement of the high-grade rocks over the cool rocks of the adjacent craton. These low-angle thrusts also account for the presence of high-grade klippen [10] located on the craton far south of the Hout River Shear Zone. Peak UHT metamorphic conditions (T > 900oC at P > 10kbar) recently reported for the SMZ [9] might have been reached at ~2.72 Ga, as is suggested by shallow northerly verging ~2.72Ga thrusts on the Kaapvaal Craton [3]. These thrusts, which are truncated by the steeply SW-verging ~2.69Ga Hout River Shear Zone are probably linked to a crustal thickening event that controlled the initial burial of SMZ granulites to depths >30 km. Integrated D-P-T-t paths constructed for hanging wall granulites and footwall greenstones provide evidence in support of a tectonic model for the evolution of the SMZ (and of the Limpopo Complex as a whole) that is either linked to a crustal thickening event involving the collision in the Neoarchean of the Kaapvaal and Zimbabwe cratons [10] or to a gravitational redistribution model [1]. References: [1] Gerya, T.V., Perchuk, L.L., Van Reenen, D.D., and Smit, C.A. 2000. J. Geodynamics, 30, 17-35. [2] Kreissig, K., Holzer, L., Frei, R., Villa, I.M., Kramers, J.D., Smit, C.A., and Van Reenen, D.D. 2001. Precambrian Resarch, 109, 145-173. [3] Passeraub, M., Wuest, T., Kreissig, K., Smit, C.A., Kramers, J.D. 1999. S. Afr. J. Geology 102, n.4, 323-334. [4] Perchuk, L.L., Gerya., T.V., Van Reenen, D.D., Sefanov, O.G., and Smit, C.A. 1996. Petrology, 4, 571-599. [5] Perchuk, L.L., Gerya, T.V., Van Reenen, D.D., Smit, C.A., Krotov, A.V., and Safanov, O.G. 2000. Mineralogy and Petrology, 69, 69-108 [6] Perchuk, L.L., Gerya, T.V., Van Reenen, D.D., Smit, C.A., and Krotov, A.V. 2000. Min. Pet, 69, 109-141. [7] Perchuk, L.L., Gerya, T.V., Van Reenen, D.D., and Smit, C.A., 2001. Gondwana Research, 4, 729-732. [8] Smit, C.A., Van Reenen, D.D, Gerya, T.V., and Perchuk, L.L. 2001. J. Metamorphic Geololgy, 19, 249-268. [9] Tsunogae,T., Miyano, T., Van Reenen, D. D., and Smit, C.A., 2004. J. Mineralogy and Petrology, 99, 213-224. [10] Van Reenen, D.D., Roering, C., Ashwal, L.D., and de Wit, M.J. 1992 (Eds). Precambrian Research, 55, 1-587.

Outcomes of therapeutic hypothermia in unconscious patients after near-hanging.

PubMed

Lee, Byung Kook; Jeung, Kyung Woon; Lee, Hyoung Youn; Lim, Jae Hoon

2012-09-01

Hanging has been increasingly used to commit suicide. There is no specific treatment besides general intensive care after near-hanging. Therapeutic hypothermia (TH) has been used in unconscious patients after near-hanging. To describe the outcomes in unconscious patients after near-hanging in order to determine whether TH improves the outcome of near-hanging injury. Medical charts were reviewed of unconscious patients after near-hanging who presented to Chonnam National University Hospital between January 2006 and December 2010 and who were considered to be eligible for TH. According to local policy, unconscious survivors after near-hanging, whether or not they experienced cardiac arrest at the scene, were treated with TH if this was agreed by next-of-kin. There were 16 survivors of asphyxial cardiac arrest after near-hanging, of whom 13 received TH. Among them, only one (7.7%, 95% CI 1.4% to 33.3%) attained Cerebral Performance Category (CPC) 1; the other 15 patients had poor neurological outcomes (CPC 5 in seven patients and CPC 4 in eight patients). Nine of the patients did not experience cardiac arrest at the scene and of these, four received TH and five received normothermic treatment. All patients who did not have cardiac arrest recovered and were discharged with CPC 1. In this study, outcomes in unconscious near-hanging patients with cardiac arrest were poor despite treatment with TH. Before recommending TH in near-hanging patients, a prospective, randomised controlled study is required.

Hanging Out with Which Friends? Friendship-Level Predictors of Unstructured and Unsupervised Socializing in Adolescence

PubMed Central

Siennick, Sonja E.; Osgood, D. Wayne

2012-01-01

Companions are central to explanations of the risky nature of unstructured and unsupervised socializing, yet we know little about whom adolescents are with when hanging out. We examine predictors of how often friendship dyads hang out via multilevel analyses of longitudinal friendship-level data on over 5,000 middle schoolers. Adolescents hang out most with their most available friends and their most generally similar friends, not with their most at-risk or similarly at-risk friends. These findings vary little by gender and wave. Together, the findings suggest that the risks of hanging out stem from the nature of hanging out as an activity, not the nature of adolescents’ companions, and that hanging out is a context for friends’ mutual reinforcement of pre-existing characteristics. PMID:23204811

Hanging Out with Which Friends? Friendship-Level Predictors of Unstructured and Unsupervised Socializing in Adolescence.

PubMed

Siennick, Sonja E; Osgood, D Wayne

2012-12-01

Companions are central to explanations of the risky nature of unstructured and unsupervised socializing, yet we know little about whom adolescents are with when hanging out. We examine predictors of how often friendship dyads hang out via multilevel analyses of longitudinal friendship-level data on over 5,000 middle schoolers. Adolescents hang out most with their most available friends and their most generally similar friends, not with their most at-risk or similarly at-risk friends. These findings vary little by gender and wave. Together, the findings suggest that the risks of hanging out stem from the nature of hanging out as an activity, not the nature of adolescents' companions, and that hanging out is a context for friends' mutual reinforcement of pre-existing characteristics.

29 CFR 1928.53 - Protective enclosures for wheel-type agricultural tractors-test procedures and performance...

Code of Federal Regulations, 2013 CFR

2013-07-01

... accomplished by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... of the pendulum will swing, or alternatively, two sets of symmetrically located cables may be used at... from the rear, followed by a load to the side on the same enclosure structure. The pendulum swinging...

An Approximate Solution to the Equation of Motion for Large-Angle Oscillations of the Simple Pendulum with Initial Velocity

ERIC Educational Resources Information Center

Johannessen, Kim

2010-01-01

An analytic approximation of the solution to the differential equation describing the oscillations of a simple pendulum at large angles and with initial velocity is discussed. In the derivation, a sinusoidal approximation has been applied, and an analytic formula for the large-angle period of the simple pendulum is obtained, which also includes…

29 CFR 1928.53 - Protective enclosures for wheel-type agricultural tractors-test procedures and performance...

Code of Federal Regulations, 2010 CFR

2010-07-01

... accomplished by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... of the pendulum will swing, or alternatively, two sets of symmetrically located cables may be used at... from the rear, followed by a load to the side on the same enclosure structure. The pendulum swinging...

Fluid-Structure Interaction in a Fluid-Filled Composite Structure Subjected to Low Velocity Impact

DTIC Science & Technology

2016-06-01

for creating an E-glass composite cubic structure and a pendulum was designed and built to provide a repeatable low velocity impact. The behavior of...structure and a pendulum was designed and built to provide a repeatable low velocity impact. The behavior of the composite structure was studied at various...SET-UP .......................................................31  1.  Impact Pendulum

29 CFR 1928.53 - Protective enclosures for wheel-type agricultural tractors-test procedures and performance...

Code of Federal Regulations, 2014 CFR

2014-07-01

...,000-kg) weight acting as a pendulum. The impact face of the weight shall be 27 ±1 in. by 27 ±1 in... restraining cables shall be located in the plane in which the center of gravity of the pendulum will swing, or... side on the same enclosure structure. The pendulum swinging from the height determined by paragraph (d...

World Pendulum--A Distributed Remotely Controlled Laboratory (RCL) to Measure the Earth's Gravitational Acceleration Depending on Geographical Latitude

ERIC Educational Resources Information Center

Grober, S.; Vetter, M.; Eckert, B.; Jodl, H.-J.

2007-01-01

We suggest that different string pendulums are positioned at different locations on Earth and measure at each place the gravitational acceleration (accuracy [delta]g is approximately equal to 0.01 m s[superscript -2]). Each pendulum can be remotely controlled via the internet by a computer located somewhere on Earth. The theoretical part describes…

29 CFR 1928.53 - Protective enclosures for wheel-type agricultural tractors-test procedures and performance...

Code of Federal Regulations, 2012 CFR

2012-07-01

... accomplished by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... of the pendulum will swing, or alternatively, two sets of symmetrically located cables may be used at... from the rear, followed by a load to the side on the same enclosure structure. The pendulum swinging...

29 CFR 1928.53 - Protective enclosures for wheel-type agricultural tractors-test procedures and performance...

Code of Federal Regulations, 2011 CFR

2011-07-01

... accomplished by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... of the pendulum will swing, or alternatively, two sets of symmetrically located cables may be used at... from the rear, followed by a load to the side on the same enclosure structure. The pendulum swinging...

Accidental hanging by a T-shirt collar in a man with morphine intoxication: an unusual case.

PubMed

Kodikara, Sarathchandra; Alagiyawanna, Ramesh

2011-09-01

Accidental hanging is rare across all age groups, and it is even rarer in the adult population except in autoerotic asphyxia. Few cases have been reported in the literature, which describe unusual patterns of accidental hanging. This article focuses on an unusual pattern of accidental hanging of a 25-year-old man, who was in a state of morphine-induced central nervous system depression and found dead in a sitting position with the collar of his T-shirt hanging off a jutting-out root of a tree. The hanged collar acted as a ligature compressing the neck.

Retrospective analysis of 319 hanging and strangulation cases between 2001 and 2014 in Shanghai.

PubMed

Ma, Jianlong; Jing, Haojia; Zeng, Yan; Tao, Li; Yang, Yulei; Ma, Kaijun; Chen, Long

2016-08-01

In this study, we retrospectively analyzed 141 cases of hanging and 178 cases of ligature strangulation recorded in the Shanghai Municipal Public Security Bureau between January 2001 and December 2014 to explore the characteristics of hanging and ligature strangulation and to supply a scientific reference for forensic pathology. Several significant differences between hanging and ligature strangulation were found. Hanging cases were mostly suicide, with some accidental cases. Strangulation cases were mostly homicide, with a few cases of suicide or sexual asphyxia. Male hanging was more common than female hanging, with a ratio of 5:2. However, there were more female than male strangulation cases, with a ratio of 13:5. The ligature marks in hanging cases were almost all of a "U" type and above the hyoid bone. The ligature marks in strangulation cases were almost always a closed circle, but the position varied. The most common vital reactions were subcutaneous hemorrhage, exfoliation and blister, which are strong evidence of antemortem injury. Hemorrhagic spots were found on the temporalis, scalp, chest and back in strangulation cases, but were rare in hanging cases. Hemorrhagic manifestations were most common in the sternocleidomastoid muscle in hanging cases, and in the sternohyoid and sternothyroid muscles in strangulation cases. Fractures occurred in only ∼17% of victims. There are notable differences between hanging and ligature strangulation, which can help distinguish between these causes of death. These characteristics should be considered in forensic practice. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Role of tectonic inheritance in the instauration of Tunisian Atlassic fold-and-thrust belt: Case of Bouhedma - Boudouaou structures

NASA Astrophysics Data System (ADS)

Ghanmi, Mohamed Abdelhamid; Ghanmi, Mohamed; Aridhi, Sabri; Ben Salem, Mohamed Sadok; Zargouni, Fouad

2016-07-01

Tectonic inversion in the Bouhedma-Boudouaou Mountains was investigated through recent field work and seismic lines interpretation calibrated with petroleum well data. Located to the Central-Southern Atlas of Tunisia, this area signed shortened intra-continental fold-and-thrust belts. Two dissymmetric anticlines characterize Bouhedma - Boudouaou major fold. These structures show a strong virgation respectively from E-W to NNE-SSW as a response to the interference between both tectonic inversion and tectonic inheritance. This complex geometry is driven by Mesozoic rifting, which marked an extensional inherited regime. A set of late Triassic-Early Jurassic E-W and NW-SE normal faults dipping respectively to the North and to the East seems to widely affect the overall geodynamic evolution of this domain. They result in major thickness changes across the hanging wall and the footwall blocks in response with the rifting activity. Tectonic inversion is inferred from convergence between African and European plates since late Cretaceous. During Serravalian - Tortonian event, NW-SE trending paroxysm led to: 1) folding of pre-inversion and syn-inversion strata, 2) reactivation of pre-existing normal faults to reverse ones and 3) orogeny of the main structures with NE-SW and E-W trending. The compressional feature still remains active during Quaternary event (Post-Villafranchian) with N-S trending compression. Contraction during inversion generates folding and internal deformation as well as Fault-Propagation-Fold and folding related strike.

Deformation during terrane accretion in the Saint Elias orogen, Alaska

USGS Publications Warehouse

Bruhn, R.L.; Pavlis, T.L.; Plafker, G.; Serpa, L.

2004-01-01

The Saint Elias orogen of southern Alaska and adjacent Canada is a complex belt of mountains formed by collision and accretion of the Yakutat terrane into the transition zone from transform faulting to subduction in the northeast Pacific. The orogen is an active analog for tectonic processes that formed much of the North American Cordillera, and is also an important site to study (1) the relationships between climate and tectonics, and (2) structures that generate large- to great-magnitude earthquakes. The Yakutat terrane is a fragment of the North American plate margin that is partly subducted beneath and partly accreted to the continental margin of southern Alaska. Interaction between the Yakutat terrane and the North American and Pacific plates causes significant differences in the style of deformation within the terrane. Deformation in the eastern part of the terrane is caused by strike-slip faulting along the Fairweather transform fault and by reverse faulting beneath the coastal mountains, but there is little deformation immediately offshore. The central part of the orogen is marked by thrusting of the Yakutat terrane beneath the North American plate along the Chugach-Saint Elias fault and development of a wide, thin-skinned fold-and-thrust belt. Strike-slip faulting in this segment may he localized in the hanging wall of the Chugach-Saint Elias fault, or dissipated by thrust faulting beneath a north-northeast-trending belt of active deformation that cuts obliquely across the eastern end of the fold-and-thrust belt. Superimposed folds with complex shapes and plunging hinge lines accommodate horizontal shortening and extension in the western part of the orogen, where the sedimentary cover of the Yakutat terrane is accreted into the upper plate of the Aleutian subduction zone. These three structural segments are separated by transverse tectonic boundaries that cut across the Yakutat terrane and also coincide with the courses of piedmont glaciers that flow from the topographic backbone of the Saint Elias Mountains onto the coastal plain. The Malaspina fault-Pamplona structural zone separates the eastern and central parts of the orogen and is marked by reverse faulting and folding. Onshore, most of this boundary is buried beneath the western or "Agassiz" lobe of the Malaspina piedmont glacier. The boundary between the central fold-and-thrust belt and western zone of superimposed folding lies beneath the middle and lower course of the Bering piedmont glacier. ?? 2004 Geological Society of America.

An energy-optimal solution for transportation control of cranes with double pendulum dynamics: Design and experiments

NASA Astrophysics Data System (ADS)

Sun, Ning; Wu, Yiming; Chen, He; Fang, Yongchun

2018-03-01

Underactuated cranes play an important role in modern industry. Specifically, in most situations of practical applications, crane systems exhibit significant double pendulum characteristics, which makes the control problem quite challenging. Moreover, most existing planners/controllers obtained with standard methods/techniques for double pendulum cranes cannot minimize the energy consumption when fulfilling the transportation tasks. Therefore, from a practical perspective, this paper proposes an energy-optimal solution for transportation control of double pendulum cranes. By applying the presented approach, the transportation objective, including fast trolley positioning and swing elimination, is achieved with minimized energy consumption, and the residual oscillations are suppressed effectively with all the state constrains being satisfied during the entire transportation process. As far as we know, this is the first energy-optimal solution for transportation control of underactuated double pendulum cranes with various state and control constraints. Hardware experimental results are included to verify the effectiveness of the proposed approach, whose superior performance is reflected by being experimentally compared with some comparative controllers.

Measurement of Motion Transfer Functions for Mirror Suspensions

NASA Astrophysics Data System (ADS)

Stuver, Amber; Beilby, Mark; Glancy, Aran; Gonzalez, Gabriela

2001-04-01

Interferometric gravitational wave detectors, such as LIGO, use mirrors suspended in pendulums. The current LIGO dectors use simple pendulums, but advanced LIGO detectors will use multiple pendulums with some stages on soft vertical springs. A drawback of the a multiple pendulum design is that it is difficult to model and predict cross couplings from one vibrational mode to another due to slight unavoidable asymmetries in the real system. Of most concern are the couplings to motion along the optical axis and into angular motions, which have the most potential to contaminate data. Our research focuses on the experimental testing of the pendulum designs for cross couplings with a special dedicated shaking stage. The cross couplings in each degree of freedom, their isolation and damping are investigated in this research though the measurement of transfer functions as filtered though the suspension system. This research is supported by The Pennsylvania State University, the NSF Grant no. PHY-9870032, and the REU program at The Pennsylvania State University.

Proposal of a new electromechanical total artificial heart: the TAH Serpentina.

PubMed

Sauer, I M; Frank, J; Bücherl, E S

1999-03-01

A new type of energy converter for an electro-mechanical total artificial heart (TAH) based on the principle of a unidirectional moving motor is described. Named the TAH Serpentina, the concept consists of 2 major parts, a pendulum shaped movable element fixed on one side using a joint bearing and a special shaped drum cam. Pusher plates are mounted flexibly to the crossbar of the pendulum. A motor drives the special shaped drum cam linked to the pendulum through a ball bearing. The circular motion of the unidirectional moving brushless DC motor is transferred into the linear motion of the pendulum to drive the pusher plates. Using a crossbar with a variable length, the stroke of the pendulum and therefore the displaced blood volume is alterable. To achieve a variable length, an electric driven screw thread or a hydraulic system is possible. Comparable to the natural heart, cardiac output would be determined by frequency and stroke volume.

Idealisation and Galileo's Pendulum Discoveries: Historical, Philosophical and Pedagogical Considerations

NASA Astrophysics Data System (ADS)

Matthews, Michael R.

2004-11-01

Galileo's discovery of the properties of pendulum motion depended on his adoption of the novel methodology of idealisation. Galileo's laws of pendulum motion could not be accepted until the empiricist methodological constraints placed on science by Aristotle, and by common sense, were overturned. As long as scientific claims were judged by how the world was immediately seen to behave, and as long as mathematics and physics were kept separate, then Galileo's pendulum claims could not be substantiated; the evidence was against them. Proof of the laws required not just a new science, but a new way of doing science, a new way of handling evidence, a new methodology of science. This was Galileo's method of idealisatioin. It was the foundation of the Galilean-Newtonian Paradigm which characterised the Scientific Revolution of the 17th century, and the subsequent centuries of modern science. As the pendulum was central to Galileo's and Newton's physics, appreciating the role of idealisation in their work is an instructive way to learn about the nature of science.

High-velocity frictional strength across the Tohoku-Oki megathrust determined from surface drilling torque

NASA Astrophysics Data System (ADS)

Ujiie, K.; Inoue, T.; Ishiwata, J.

2015-12-01

Frictional strength at seismic slip rates is a key to evaluate fault weakening and rupture propagation during earthquakes. The Japan Trench First Drilling Project (JFAST) drilled through the shallow plate-boundary thrust, where huge displacements of ~50 m occurred during the 2011 Tohoku-Oki earthquake. To determine the downhole frictional strength at drilled site (Site C0019), we analyzed surface drilling data. The equivalent slip rate estimated from the rotation rate and inner and outer radiuses of the drill bit ranges from 0.8 to 1.3 m/s. The measured torque includes the frictional torque between the drilling string and borehole wall, the viscous torque between the drilling string and seawater/drilling fluid, and the drilling torque between the drill bit and sediments. We subtracted the former two from the measured torque using the torque data during bottom-up rotating operations at several depths. Then, the shear stress was calculated from the drilling torque taking the configuration of the drill bit into consideration. The normal stress was estimated from the weight on bit data and the projected area of the drill bit. Assuming negligible cohesion, the frictional strength was obtained by dividing shear stress by normal stress. The results show a clear contrast in high-velocity frictional strength across the plate-boundary thrust: the friction coefficient of frontal prism sediments (hemipelagic mudstones) in hanging wall is 0.1-0.2, while that in subducting sediments (hemipelagic to pelagic mudstones and chert) in footwall increases to 0.2-0.4. The friction coefficient of smectite-rich pelagic clay in the plate-boundary thrust is ~0.1, which is consistent with that obtained from high-velocity (1.3 m/s) friction experiments and temperature measurements. We conclude that surface drilling torque provides useful data to obtain a continuous downhole frictional strength.

Modeling and Model Identification of Autonomous Underwater Vehicles

DTIC Science & Technology

2015-06-01

setup, based on a quadrifilar pendulum , is developed to measure the moments of inertia of the vehicle. System identification techniques, based on...parametric models of the platforms: an individual channel excitation approach and a free decay pendulum test. The former is applied to THAUS, which can...excite the system in individual channels in four degrees of freedom. These results are verified in the free decay pendulum setup, which has the

29 CFR 1928.52 - Protective frames for wheel-type agricultural tractors-test procedures and performance requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be 27 ±1 in... restraining cables shall be located in the plane in which the center of gravity of the pendulum will swing, or... pendulum swinging from the height determined by paragraph (d)(3)(ii) of this section shall be used to...

29 CFR 1926.1002 - Protective frames (roll-over protective structures, known as ROPS) for wheel-type agricultural...

Code of Federal Regulations, 2012 CFR

2012-07-01

... produced by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... the center of gravity of the pendulum will swing, or more than one restraining cable shall give a... to the side on the same frame. The pendulum dropped from the height (see the definition of “H” in...

29 CFR 1926.1002 - Protective frames (roll-over protective structures, known as ROPS) for wheel-type agricultural...

Code of Federal Regulations, 2011 CFR

2011-07-01

... produced by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... the center of gravity of the pendulum will swing, or more than one restraining cable shall give a... to the side on the same frame. The pendulum dropped from the height (see the definition of “H” in...

29 CFR 1926.1002 - Protective frames (roll-over protective structures, known as ROPS) for wheel-type agricultural...

Code of Federal Regulations, 2010 CFR

2010-07-01

... produced by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... the center of gravity of the pendulum will swing, or more than one restraining cable shall give a... to the side on the same frame. The pendulum dropped from the height (see the definition of “H” in...

The experimental determination of the moments of inertia of airplanes by a simplified compound-pendulum method

NASA Technical Reports Server (NTRS)

Gracey, William

1948-01-01

A simplified compound-pendulum method for the experimental determination of the moments of inertia of airplanes about the x and y axes is described. The method is developed as a modification of the standard pendulum method reported previously in NACA report, NACA-467. A brief review of the older method is included to form a basis for discussion of the simplified method. (author)

29 CFR 1926.1002 - Protective frames (roll-over protective structures, known as ROPS) for wheel-type agricultural...

Code of Federal Regulations, 2013 CFR

2013-07-01

... produced by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... the center of gravity of the pendulum will swing, or more than one restraining cable shall give a... to the side on the same frame. The pendulum dropped from the height (see the definition of “H” in...

Theoretical Pressure Distribution, Apparent Mass, and Moment of Inertia of a Disk Pendulum Oscillating at Low Frequency. M.S. Thesis - George Washington Univ., Washington, D. C.

NASA Technical Reports Server (NTRS)

Dunning, R. S.

1973-01-01

Equations are developed which give the pressure profile, the forces and torques on a disk pendulum by means of point source wave theory from acoustics. The pressure, force and torque equations for an unbaffled disk are developed. These equations are then used to calculate the apparent mass and apparent inertia for the pendulum.

29 CFR 1926.1002 - Protective frames (roll-over protective structures, known as ROPS) for wheel-type agricultural...

Code of Federal Regulations, 2014 CFR

2014-07-01

... produced by using a 4,410-lb (2,000-kg) weight acting as a pendulum. The impact face of the weight shall be... the center of gravity of the pendulum will swing, or more than one restraining cable shall give a... to the side on the same frame. The pendulum dropped from the height (see the definition of “H” in...

A Clinically Realistic Large Animal Model of Intra-Articular Fracture

DTIC Science & Technology

2014-12-01

pendulum system for measuring energy absorption during fracture insult to large animal joints in vivo. J Biomech Eng. 2014 Jun;136(6):064502. PMID:24760051...Model 4. Yucatan Minipig 5. Impact 6. Pendulum 7. Mankin Scoring 8. Inflammatory Cytokines 9. Gait Analysis 10. Incongruity 3. OVERALL...primarily hardware upgrades and ex-vivo experimentation of the pendulum . 3.2.a Device Upgrades The primary hardware upgrade was to instrument the

Novel Out-Coupling Techniques for Terahertz Free Electron Lasers

DTIC Science & Technology

2012-06-01

4  1.   FEL “ Pendulum ” Equation and Electron Dynamics .......................4  2.   FEL...4 B. FEL THEORY 1. FEL “ Pendulum ” Equation and Electron Dynamics The dynamics of electron motion as it passes through the undulator are governed...I.5, then the FEL “ pendulum equation” is derived , (I.7) where is the dimensionless laser field amplitude[1]. From this, it is shown that changes

In full swing? How do pendulum migrant labourers in Vietnam adjust their sexual perspectives to their rural-urban lives?

PubMed

Nguyen, Huong Ngoc; Hardesty, Melissa; Hong, Khuat Thu

2011-11-01

Having emerged only recently due to fast urbanisation and globalisation, pendulum migrant labourers in Vietnam are economically, culturally and socially difficult to locate - though they are estimated to number in their millions. Defined by their frequent migration between village and city, pendulum migrant labourers occupy an extended period of liminality. Are they traditional villagers or liberal city people when it comes to sex? Does city life radically change their views on sexuality? Starting with the premise that living environments play a key role in structuring the practical and symbolic realities of sex, this paper explores how extended periods of circular migration between the village and city - living environments that differ markedly in terms of socioeconomic and cultural conditions - affect the sexual views and perspectives of Vietnamese pendulum migrant labourers. Analysis from in-depth interviews with 23 married pendulum migrant labourers revealed that even though they had been living the pendulum life for several years, they continued to identify themselves, sexually, as traditional villagers. Among labourers the link between sexuality and living environment was a matter of pragmatism - matching 'suitable' sexual behaviour to social, even if imagined, location - and of privilege or 'leagues' - matching behaviour and comportment to social pedigree.

Clinical Usefulness of the Pendulum Test Using a NK Table to Measure the Spasticity of Patients with Brain Lesions

PubMed Central

Kim, Yong-Wook

2013-01-01

. [Purpose] The purpose of the present study was to investigate the clinical usefulness (reliability and validity) of the pendulum test using a Noland-Kuckhoff (NK) table with an attached electrogoniometer to measure the spasticity of patients with brain lesions. [Subjects] The subjects were 31 patients with stroke or traumatic brain injury. [Methods] The intraclass correlation coefficient (ICC) was used to verify the test–retest reliability of spasticity measures obtained using the pendulum test. Pearson's product correlation coefficient was used to examine the validity of the pendulum test using the amplitude of the patellar tendon reflex (PTR) test, an objective and quantitative measure of spasticity. [Results] The test–retest reliability was high, reflecting a significant correlation between the test and the retest (ICCs = 0.95–0.97). A significant negative correlation was found between the amplitude of the PTR test and the four variables measured in the pendulum test (r = −0.77– −0.85). [Conclusion] The pendulum test using a NK table is an objective measure of spasticity and can be used in the clinical setting in place of more expensive and complicated equipment. Further studies are needed to investigate the therapeutic effect of this method on spasticity. PMID:24259775

Clinical usefulness of the pendulum test using a NK table to measure the spasticity of patients with brain lesions.

PubMed

Kim, Yong-Wook

2013-10-01

. [Purpose] The purpose of the present study was to investigate the clinical usefulness (reliability and validity) of the pendulum test using a Noland-Kuckhoff (NK) table with an attached electrogoniometer to measure the spasticity of patients with brain lesions. [Subjects] The subjects were 31 patients with stroke or traumatic brain injury. [Methods] The intraclass correlation coefficient (ICC) was used to verify the test-retest reliability of spasticity measures obtained using the pendulum test. Pearson's product correlation coefficient was used to examine the validity of the pendulum test using the amplitude of the patellar tendon reflex (PTR) test, an objective and quantitative measure of spasticity. [Results] The test-retest reliability was high, reflecting a significant correlation between the test and the retest (ICCs = 0.95-0.97). A significant negative correlation was found between the amplitude of the PTR test and the four variables measured in the pendulum test (r = -0.77- -0.85). [Conclusion] The pendulum test using a NK table is an objective measure of spasticity and can be used in the clinical setting in place of more expensive and complicated equipment. Further studies are needed to investigate the therapeutic effect of this method on spasticity.

Foucault pendulum with eddy-current damping of the elliptical motion

NASA Astrophysics Data System (ADS)

Mastner, G.; Vokurka, V.; Maschek, M.; Vogt, E.; Kaufmann, H. P.

1984-10-01

A newly designed Foucault pendulum is described in which the mechanical Charron ring, used throughout in previous designs for damping of the elliptical motion of the pendulum, is replaced by an electromagnetic eddy-current brake, consisting of a permanent magnet attached to the bottom of the bob and a metallic ring. This damping device is very efficient, as it is self-aligning, symmetrical in the damping effect, and never wears out. The permanent magnet is also used, together with a coil assembly and an electronic circuitry, for the dipole-torque drive of the pendulum as well as for accurate stabilization of the amplitude of the swing. A latched time display, controlled by Hall probes activated by the magnet, is used to visualize the Foucault rotation. The pendulum system and its associated electronic circuitry are described in detail. The optimizing of the drive mode is discussed. Measurements of deviations from theoretical value of the Foucault rotation velocity made automatically in a continuous run show a reproducible accuracy of ±1% or better in individual 360° rotations during the summer months. The quality factor of the pendulum as mechanical resonator was measured as a function of the amplitude in the presence of the eddy-current damping ring.

Human balancing of an inverted pendulum: position control by small, ballistic-like, throw and catch movements

PubMed Central

Loram, Ian D; Lakie, Martin

2002-01-01

In standing, there are small sways of the body. Our interest is to use an artificial task to illuminate the mechanisms underlying the sways and to account for changes in their size. Using the ankle musculature, subjects balanced a large inverted pendulum. The equilibrium of the pendulum is unstable and quasi-regular sway was observed like that in quiet standing. By giving full attention to minimising sway subjects could systematically reduce pendulum movement. The pendulum position, the torque generated at each ankle and the soleus and tibialis anterior EMGs were recorded. Explanations about how the human inverted pendulum is balanced usually ignore the fact that balance is maintained over a range of angles and not just at one angle. Any resting equilibrium position of the pendulum is unstable and in practice temporary; movement to a different resting equilibrium position can only be accomplished by a biphasic ‘throw and catch’ pattern of torque and not by an elastic mechanism. Results showed that balance was achieved by the constant repetition of a neurally generated ballistic-like biphasic pattern of torque which can control both position and sway size. A decomposition technique revealed that there was a substantial contribution to changes in torque from intrinsic mechanical ankle stiffness; however, by itself this was insufficient to maintain balance or to control position. Minimisation of sway size was caused by improvement in the accuracy of the anticipatory torque impulses. We hypothesise that examination of centre of mass and centre of pressure data for quiet standing will duplicate these results. PMID:11986396

University of Florida Torsion Pendulum for Testing Key LISA Technology

NASA Astrophysics Data System (ADS)

Apple, Stephen; Chilton, Andrew; Olatunde, Taiwo Janet; Hillsberry, Daniel; Parry, Samantha; Ciani, Giacomo; Wass, Peter; Mueller, Guido; Conklin, John

2018-01-01

This presentation will describe the design and performance of a new torsion pendulum at the University of Florida used for testing inertial sensors and associated technologies for use in space – based gravitational wave observatories and geodesy missions. In particular this new torsion pendulum facility is testing inertial sensors and associated technology for the upcoming LISA (laser interferometer space antenna) space-based gravitational wave observatory mission. The torsion pendulum apparatus is comprised of a suspended cross bar assembly that has LISA test mass mockups at each of its ends. Two of the test mass mockups are enclosed by capacitive sensors which provide actuation and position sensing. The entire assembly is housed in a vacuum chamber. The pendulum cross-bar converts rotational motion of the test masses about the suspension fiber axis into translational motion. The 22 cm cross bar arm length along with the extremely small torsional spring constant of the suspension fiber results in a near free fall condition in the translational degree-of-freedom orthogonal to both the member and the suspension fiber. The test masses are electrically isolated from the pendulum assembly and their charge is controlled via photoemission using fiber coupled UV LEDS. Position of the test masses is measured using both capacitive and interferometric readout. The broadband sensitivity of the capacitive readout and laser interferometer readout is 30 nm/√Hz and 0.5 nm/√Hz respectively. The performance of the pendulum measured in equivalent acceleration noise acting on a LISA test mass is approximately 3 × 10-13 ms-2/√Hz at 2 mHz. This presentation will also discuss the design and fabrication of a flight-like gravitational reference sensor that will soon be integrated into the torsion pendulum facility. This flight-like GRS will allow for noise performance measurements in a more LISA-like configuration.

Evaluation of dynamic electromagnetic tracking deviation

NASA Astrophysics Data System (ADS)

Hummel, Johann; Figl, Michael; Bax, Michael; Shahidi, Ramin; Bergmann, Helmar; Birkfellner, Wolfgang

2009-02-01

Electromagnetic tracking systems (EMTS's) are widely used in clinical applications. Many reports have evaluated their static behavior and errors caused by metallic objects were examined. Although there exist some publications concerning the dynamic behavior of EMTS's the measurement protocols are either difficult to reproduce with respect of the movement path or only accomplished at high technical effort. Because dynamic behavior is of major interest with respect to clinical applications we established a simple but effective modal measurement easy to repeat at other laboratories. We built a simple pendulum where the sensor of our EMTS (Aurora, NDI, CA) could be mounted. The pendulum was mounted on a special bearing to guarantee that the pendulum path is planar. This assumption was tested before starting the measurements. All relevant parameters defining the pendulum motion such as rotation center and length are determined by static measurement at satisfactory accuracy. Then position and orientation data were gathered over a time period of 8 seconds and timestamps were recorded. Data analysis provided a positioning error and an overall error combining both position and orientation. All errors were calculated by means of the well know equations concerning pendulum movement. Additionally, latency - the elapsed time from input motion until the immediate consequences of that input are available - was calculated using well-known equations for mechanical pendulums for different velocities. We repeated the measurements with different metal objects (rods made of stainless steel type 303 and 416) between field generator and pendulum. We found a root mean square error (eRMS) of 1.02mm with respect to the distance of the sensor position to the fit plane (maximum error emax = 2.31mm, minimum error emin = -2.36mm). The eRMS for positional error amounted to 1.32mm while the overall error was 3.24 mm. The latency at a pendulum angle of 0° (vertical) was 7.8ms.

3-D simulation of hanging wall effect at dam site

NASA Astrophysics Data System (ADS)

Zhang, L.; Xu, Y.

2017-12-01

Hanging wall effect is one of the near fault effects. This paper focuses on the difference of the ground motions on the hanging wall side between the footwall side of the fault at dam site considering the key factors, such as actual topography, the rupture process. For this purpose, 3-D ground motions are numerically simulated by the spectrum element method (SEM), which takes into account the physical mechanism of generation and propagation of seismic waves. With the SEM model of 548 million DOFs, excitation and propagation of seismic waves are simulated to compare the difference between the ground motion on the hanging wall side and that on the footwall side. Take Dagangshan region located in China as an example, several seismogenic finite faults with different dip angle are simulated to investigate the hanging wall effect. Furthermore, by comparing the ground motions of the receiving points, the influence of several factors on hanging wall effect is investigated, such as the dip of the fault and the fault type (strike slip fault or dip-slip fault). The peak acceleration on the hanging wall side is obviously larger than those on the footwall side, which numerically evidences the hanging wall effect. Besides, the simulation shows that only when the dip is less than 70° does the hanging wall effect deserve attention.

Integrated Data Collection and Analysis Project: Friction Correlation Study

DTIC Science & Technology

2015-08-01

methods authorized in AOP-7 include Pendulum Friction, Rotary Friction, Sliding Friction (ABL), BAM Friction and Steel/Fiber Shoe Methods. The...sensitivity can be obtained by Pendulum Friction, Rotary Friction, Sliding Friction (such as the ABL), BAM Friction and Steel/Fiber Shoe Methods.3, 4 Within...Figure 4.16 A variable compressive force is applied downward through the wheel hydraulically (50-1995 psi). The 5 kg pendulum impacts (8 ft/sec is the

Quantum Simulation and Quantum Sensing with Ultracold Strontium

DTIC Science & Technology

2015-09-18

quantum Kapitza pendulum , a novel Floquet system which we are investigating using modulated optical lattices. We have proposed and are developing...another goal of our AFOSR YIP project. To this end, we have developed the first theoretical treatment of a lattice-based quantum Kapitza pendulum . We have...classical single-particle analogue of this phase occurs in a rigid pendulum with an oscillating support (known as a Kapitza pendu- lum [9]). To prepare for

Two-Pendulum Model of Propellant Slosh in Europa Clipper PMD Tank

NASA Technical Reports Server (NTRS)

Ng, Wanyi; Benson, David

2017-01-01

Model propellant slosh for Europa Clipper using two pendulums such that controls engineers can predict slosh behavior during the mission. Importance of predicting propellant slosh; (1) Sloshing changes CM (center of mass) of spacecraft and exerts forces and torques on spacecraft. (2) Avoid natural frequencies of structures. (3) Size ACS (Attitude Control Systems) thrusters to counteract forces and torques. Can model sloshing fluid as two pendulums with specific parameters (mass, length, damping),

An Empirical Model for Mine-Blast Loading

DTIC Science & Technology

2014-10-17

fledged experimental program. The numerical approach however suffers from several drawbacks in the mine blast simulations. First, it is a very...Suffield consisted in a pendulum type device to measure global impulse of buried mine [15]. One of the main purposes of the ONAGER pendulum was to study...TP-1 Terminal effects, KTA 1-34 report, 2004. [15] Bues, R., Hlady, S.L. and Bergeron, D.M., Pendulum Measurement of Land Mine Blast Output, Volume

Simple pendulum for blind students

NASA Astrophysics Data System (ADS)

Goncalves, A. M. B.; Cena, C. R.; Alves, D. C. B.; Errobidart, N. C. G.; Jardim, M. I. A.; Queiros, W. P.

2017-09-01

Faced with the need to teach physics to the visually impaired, in this paper we propose a way to demonstrate the dependence of distance and time in a pendulum experiment to blind students. The periodic oscillation of the pendulum is translated, by an Arduino and an ultrasonic sensor, in a periodic variation of frequency in a speaker. The main advantage of this proposal is the possibility that a blind student understands the movement without necessity of touching it.

Precision Measurement of Distribution of Film Thickness on Pendulum for Experiment of G

NASA Astrophysics Data System (ADS)

Liu, Lin-Xia; Guan, Sheng-Guo; Liu, Qi; Zhang, Ya-Ting; Shao, Cheng-Gang; Luo, Jun

2009-09-01

Distribution of film thickness coated on the pendulum of measuring the Newton gravitational constant G is determined with a weighing method by means of a precision mass comparator. The experimental result shows that the gold film on the pendulum will contribute a correction of -24.3 ppm to our G measurement with an uncertainty of 4.3 ppm, which is significant for improving the G value with high precision.

Pendulum motions of extended lunar space elevator

NASA Astrophysics Data System (ADS)

Burov, A. A.; Kosenko, I. I.

2014-09-01

In the usual everyday life, it is well known that the inverted pendulum is unstable and is ready to fall to "all four sides," to the left and to the right, forward and backward. The theoretical studies and the lunar experience of moon robots and astronauts also confirms this property. The question arises: Is this property preserved if the pendulum is "very, very long"? It turns out that the answer is negative; namely, if the pendulum length significantly exceeds the Moon radius, then the radial equilibria at which the pendulum is located along the straight line connecting the Earth and Moon centers are Lyapunov stable and the pendulum does not fall in any direction at all. Moreover, if the pendulum goes beyond the collinear libration points, then it can be extended and manufactured from cables. This property was noted by F. A. Tsander and underlies the so-called lunar space elevator (e.g., see [1]). In the plane of the Earth and Moon orbits, there are some other equilibria which turn out to be unstable. The question is, Are there equilibria at which the pendulum is located outside the orbital plane? In this paper, we show that the answer is positive, but such equilibria are unstable in the secular sense. We also study necessary conditions for the stability of lunar pendulum oscillations in the plane of the lunar orbit. It was numerically discovered that stable and unstable equilibria alternate depending on the oscillation amplitude and the angular velocity of rotation. The study of the lunar elevator dynamics originates in [2]. The concept of lunar elevator was developed in detail in [3, 4]. Several classes of equilibria with the finiteness of the Moon size taken into account were studied in [5]. The possibility of location of an orbital station fixed to the Moon surface by a pair of tethers was investigated in [6]. The problem of orientation of the terminal station of the lunar space elevator was studied in [7]. The influence of the tether length variations on the motion of the lunar tether system was considered in [8]. The alternation of stable and unstable flat oscillations is well known in the problem of satellite oscillations in a circular orbit [9, 10].

Light rays and the tidal gravitational pendulum

NASA Astrophysics Data System (ADS)

Farley, A. N. St J.

2018-05-01

Null geodesic deviation in classical general relativity is expressed in terms of a scalar function, defined as the invariant magnitude of the connecting vector between neighbouring light rays in a null geodesic congruence projected onto a two-dimensional screen space orthogonal to the rays, where λ is an affine parameter along the rays. We demonstrate that η satisfies a harmonic oscillator-like equation with a λ-dependent frequency, which comprises terms accounting for local matter affecting the congruence and tidal gravitational effects from distant matter or gravitational waves passing through the congruence, represented by the amplitude, of a complex Weyl driving term. Oscillating solutions for η imply the presence of conjugate or focal points along the rays. A polarisation angle, is introduced comprising the orientation of the connecting vector on the screen space and the phase, of the Weyl driving term. Interpreting β as the polarisation of a gravitational wave encountering the light rays, we consider linearly polarised waves in the first instance. A highly non-linear, second-order ordinary differential equation, (the tidal pendulum equation), is then derived, so-called due to its analogy with the equation describing a non-linear, variable-length pendulum oscillating under gravity. The variable pendulum length is represented by the connecting vector magnitude, whilst the acceleration due to gravity in the familiar pendulum formulation is effectively replaced by . A tidal torque interpretation is also developed, where the torque is expressed as a coupling between the moment of inertia of the pendulum and the tidal gravitational field. Precessional effects are briefly discussed. A solution to the tidal pendulum equation in terms of familiar gravitational lensing variables is presented. The potential emergence of chaos in general relativity is discussed in the context of circularly, elliptically or randomly polarised gravitational waves encountering the null congruence.

Two-Pendulum Model of Propellant Slosh in Europa Clipper PMD Tank

NASA Technical Reports Server (NTRS)

Ng, Wanyi; Benson, David

2017-01-01

The objective of this fluids analysis is to model propellant slosh for the Europa Clipper mission using a two-pendulum model, such that controls engineers can predict slosh behavior during the mission. Propellant slosh causes shifts in center of mass and exerts forces and torques on the spacecraft which, if not adequately controlled, can lead to mission failure. The two-pendulum model provides a computationally simple model that can be used to predict slosh for the Europa Clipper tank geometry. The Europa Clipper tank is cylindrical with a domed top and bottom and includes a propellant management device (PMD). Due to the lack of experimental data in low gravity environments, computational fluid dynamics (CFD) simulation results were used as 'real' slosh behavior for two propellants at three fill fractions. Key pendulum parameters were derived that allow the pendulum model's center of mass, forces, and moments to closely match the CFD data. The parameter trends were examined as a function of tank fill fraction and compared with solutions to analytic equations that describe the frequency of slosh in tanks with simple geometries. The trends were monotonic as expected, and parameters resembled analytical predictions; any differences could be explained by the specific differences in the geometry of the tank. This paper summarizes the new method developed at Goddard Space Flight Center (GSFC) for deriving pendulum parameters for two-pendulum equivalent sloshing models. It presents the results of this method and discusses the validity of the results. This analysis is at a completed stage and will be applied in the immediate future to the evolving tank geometry as Europa Clipper moves past its preliminary design review (PDR) phase.

Reachability and Real-Time Actuation Strategies for the Active SLIP Model

DTIC Science & Technology

2015-06-01

spring leg, the Spring Loaded Inverted Pendulum (SLIP) is a prevalent model for analyzing running and hopping. In this work we consider an actuated...forced symmetry of the stance phase for the Spring-Loaded Inverted Pendulum , In Proceedings of the 2012 IEEE International Conference on Robotics and...Networks. Automatica, 49(1):206-213, 2013 (v) G. Piovan and K. Byl. Enforced symmetry of the stance phase for the spring-loaded inverted pendulum . In

Lyapunov optimal feedback control of a nonlinear inverted pendulum

NASA Technical Reports Server (NTRS)

Grantham, W. J.; Anderson, M. J.

1989-01-01

Liapunov optimal feedback control is applied to a nonlinear inverted pendulum in which the control torque was constrained to be less than the nonlinear gravity torque in the model. This necessitates a control algorithm which 'rocks' the pendulum out of its potential wells, in order to stabilize it at a unique vertical position. Simulation results indicate that a preliminary Liapunov feedback controller can successfully overcome the nonlinearity and bring almost all trajectories to the target.

UT Austin Villa 2011: 3D Simulation Team Report

DTIC Science & Technology

2011-01-01

inverted pendulum model omnidirectional walk engine based on one that was originally designed for the real Nao robot [7]. The omnidirectional walk is...using a double linear inverted pendulum , where the center of mass is swinging over the stance foot. In addition, as in Graf et al.’s work [7], we use...between the inverted pendulums formed by the respective stance feet. Notation Description maxStep∗i Maximum step sizes allowed for x, y, and θ y

Using a Modified Simple Pendulum to Find the Variations in the Value of “g”

NASA Astrophysics Data System (ADS)

Arnold, Jonathan P.; Efthimiou, C.

2007-05-01

The simple pendulum is one of the most known and studied system of Newtonian Mechanics. It also provides one of the most elegant and simple devices to measure the acceleration of gravity at any location. In this presentation we will revisit the problem of measuring the acceleration of gravity using a simple pendulum and will present a modification to the standard technique that increases the accuracy of the measurement.

Reliability and validity of pendulum test measures of spasticity obtained with the Polhemus tracking system from patients with chronic stroke

PubMed Central

Bohannon, Richard W; Harrison, Steven; Kinsella-Shaw, Jeffrey

2009-01-01

Background Spasticity is a common impairment accompanying stroke. Spasticity of the quadriceps femoris muscle can be quantified using the pendulum test. The measurement properties of pendular kinematics captured using a magnetic tracking system has not been studied among patients who have experienced a stroke. Therefore, this study describes the test-retest reliability and known groups and convergent validity of the pendulum test measures obtained with the Polhemus tracking system. Methods Eight patients with chronic stroke underwent pendulum tests with their affected and unaffected lower limbs, with and without the addition of a 2.2 kg cuff weight at the ankle, using the Polhemus magnetic tracking system. Also measured bilaterally were knee resting angles, Ashworth scores (grades 0–4) of quadriceps femoris muscles, patellar tendon (knee jerk) reflexes (grades 0–4), and isometric knee extension force. Results Three measures obtained from pendular traces of the affected side were reliable (intraclass correlation coefficient ≥ .844). Known groups validity was confirmed by demonstration of a significant difference in the measurements between sides. Convergent validity was supported by correlations ≥ .57 between pendulum test measures and other measures reflective of spasticity. Conclusion Pendulum test measures obtained with the Polhemus tracking system from the affected side of patients with stroke have good test-retest reliability and both known groups and convergent validity. PMID:19642989

Comparison of two different methods of preoperative marking for toric intraocular lens implantation: bubble marker versus pendulum marker.

PubMed

Farooqui, Javed Hussain; Koul, Archana; Dutta, Ranjan; Shroff, Noshir Minoo

2016-01-01

To compare the accuracy of two different methods of preoperative marking for toric intraocular lens (IOL) implantation, bubble marker versus pendulum marker, as a means of establishing the reference point for the final alignment of the toric IOL to achieve an outcome as close as possible to emmetropia. Toric IOLs were implanted in 180 eyes of 110 patients. One group (55 patients) had preoperative marking of both eyes done with bubble marker (ASICO AE-2791TBL) and the other group (55 patients) with pendulum marker (Rumex(®)3-193). Reference marks were placed at 3-, 6-, and 9-o'clock positions on the limbus. Slit-lamp photographs were analyzed using Adobe Photoshop (version 7.0). Amount of alignment error (in degrees) induced in each group was measured. Mean absolute rotation error in the preoperative marking in the horizontal axis was 2.42±1.71 in the bubble marker group and 2.83±2.31in the pendulum marker group (P=0.501). Sixty percent of the pendulum group and 70% of the bubble group had rotation error ≤3 (P=0.589), and 90% eyes of the pendulum group and 96.7% of the bubble group had rotation error ≤5 (P=0.612). Both preoperative marking techniques result in approximately 3 of alignment error. Both marking techniques are simple, predictable, reproducible and easy to perform.

Reliability and validity of pendulum test measures of spasticity obtained with the Polhemus tracking system from patients with chronic stroke.

PubMed

Bohannon, Richard W; Harrison, Steven; Kinsella-Shaw, Jeffrey

2009-07-30

Spasticity is a common impairment accompanying stroke. Spasticity of the quadriceps femoris muscle can be quantified using the pendulum test. The measurement properties of pendular kinematics captured using a magnetic tracking system has not been studied among patients who have experienced a stroke. Therefore, this study describes the test-retest reliability and known groups and convergent validity of the pendulum test measures obtained with the Polhemus tracking system. Eight patients with chronic stroke underwent pendulum tests with their affected and unaffected lower limbs, with and without the addition of a 2.2 kg cuff weight at the ankle, using the Polhemus magnetic tracking system. Also measured bilaterally were knee resting angles, Ashworth scores (grades 0-4) of quadriceps femoris muscles, patellar tendon (knee jerk) reflexes (grades 0-4), and isometric knee extension force. Three measures obtained from pendular traces of the affected side were reliable (intraclass correlation coefficient > or = .844). Known groups validity was confirmed by demonstration of a significant difference in the measurements between sides. Convergent validity was supported by correlations > or = .57 between pendulum test measures and other measures reflective of spasticity. Pendulum test measures obtained with the Polhemus tracking system from the affected side of patients with stroke have good test-retest reliability and both known groups and convergent validity.

A swing driven by liquid crystals

NASA Astrophysics Data System (ADS)

Cheng, Cheng

Angular momentum in liquid crystals exists as flow, director reorientation, etc. However, it is hard to observe and measure angular momentum in liquid crystals by a direct mechanical approach. Torsion pendulum is a general tool to measure angular momentum by torque balance. Our torsion pendulum can harvest the angular momentum in liquid crystals to make it observable. The oscillation of the pendulum keeps increasing by constructively adding a small angular momentum of liquid crystals each period at the resonant frequency of the pendulum. Its similar to a swing driven by a force at its resonant frequency. For the torsion pendulum, a cage made of two aluminum discs, in which a liquid crystal cell is placed, is suspended between two thin tungsten wires. A gold mirror, which is a part of the optical lever system, is attached on one tungsten wire. As first demonstration, we fabricate a circular hybrid liquid crystal cell, which can induce concentric backflows to generate angular momentum. The alignment on the planar substrate is concentric and tangential. Due to the coupling between director rotation and flow, the induced backflow goes around the cell when we add electrical pulses between top and bottom substrates. The oscillation is observed by a position sensitive detector and analyzed on the basis of Eriksen-Leslie theory. With vacuum condition and synchronous driving system, the oscillation signal is improved. We demonstrate that this torsion pendulum can sensitively detect the angular momentum in liquid crystals.

Hanging out with Which Friends? Friendship-Level Predictors of Unstructured and Unsupervised Socializing in Adolescence

ERIC Educational Resources Information Center

Siennick, Sonja E.; Osgood, D. Wayne

2012-01-01

Companions are central to explanations of the risky nature of unstructured and unsupervised socializing, yet we know little about whom adolescents are with when hanging out. We examine predictors of how often friendship dyads hang out via multilevel analyses of longitudinal friendship-level data on over 5,000 middle schoolers. Adolescents hang out…

A composite controller for trajectory tracking applied to the Furuta pendulum.

PubMed

Aguilar-Avelar, Carlos; Moreno-Valenzuela, Javier

2015-07-01

In this paper, a new composite scheme is proposed, where the total control action is composed of the sum of a feedback-linearization-based controller and an energy-based compensation. This new proposition is applied to the rotary inverted pendulum or Furuta pendulum. The Furuta pendulum is a well-known underactuated mechanical system with two degrees of freedom. The control objective in this case is the tracking of a desired periodic trajectory in the actuated joint, while the unactuated link is regulated at the upward position. The closed-loop system is analyzed showing uniformly ultimately boundedness of the error trajectories. The design procedure is shown in a constructive form, such that it may be applied to other underactuated mechanical systems, with the proper definitions of the output function and the energy function. Numerical simulations and real-time experiments show the practical viability of the controller. Finally, the proposed algorithm is compared with a tracking controller previously reported in the literature. The new algorithm shows better performance in both arm trajectory tracking and pendulum regulation. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Seismic cross-coupling noise in torsion pendulums

NASA Astrophysics Data System (ADS)

Shimoda, Tomofumi; Aritomi, Naoki; Shoda, Ayaka; Michimura, Yuta; Ando, Masaki

2018-05-01

Detection of low-frequency gravitational waves around 0.1 Hz is one of the important targets for future gravitational wave observation. One of the main sources of the expected signals is gravitational waves from binary intermediate-mass black hole coalescences which is proposed as one of the formation scenarios of supermassive black holes. By using a torsion pendulum, which can have a resonance frequency of a few millihertz, such signals can be measured on the ground since its rotational motion can act as a free mass down to 0.01 Hz. However, sensitivity of a realistic torsion pendulum will suffer from torsional displacement noise introduced from translational ground motion in the main frequency band of interest. Such noise is called seismic cross-coupling noise, and there has been little research on it. In this paper, systematic investigation is performed to identify routes of cross-coupling transfer for standard torsion pendulums. Based on the results, this paper also proposes reduction schemes of cross-coupling noise, and they were demonstrated experimentally in agreement with theory. This result establishes a basic way to reduce seismic noise in torsion pendulums for the most significant coupling routes.

Neural network-based motion control of an underactuated wheeled inverted pendulum model.

PubMed

Yang, Chenguang; Li, Zhijun; Cui, Rongxin; Xu, Bugong

2014-11-01

In this paper, automatic motion control is investigated for one of wheeled inverted pendulum (WIP) models, which have been widely applied for modeling of a large range of two wheeled modern vehicles. First, the underactuated WIP model is decomposed into a fully actuated second order subsystem Σa consisting of planar movement of vehicle forward and yaw angular motions, and a nonactuated first order subsystem Σb of pendulum motion. Due to the unknown dynamics of subsystem Σa and the universal approximation ability of neural network (NN), an adaptive NN scheme has been employed for motion control of subsystem Σa . The model reference approach has been used whereas the reference model is optimized by the finite time linear quadratic regulation technique. The pendulum motion in the passive subsystem Σb is indirectly controlled using the dynamic coupling with planar forward motion of subsystem Σa , such that satisfactory tracking of a set pendulum tilt angle can be guaranteed. Rigours theoretic analysis has been established, and simulation studies have been performed to demonstrate the developed method.

Attitude Stability of a Spacecraft with Slosh Mass Subject to Parametric Excitation

NASA Astrophysics Data System (ADS)

Kang, Ja-Young

2003-09-01

The attitude motion of a spin-stabilized, upper-stage spacecraft is investigated based on a two-body model, consisting of a symmetric body, representing the spacecraft, and a spherical pendulum, representing the liquid slag pool entrapped in the aft section of the rocket motor. Exact time-varying nonlinear equations are derived and used to eliminate the drawbacks of conventional linear models. To study the stability of the spacecraft's attitude motion, both the spacecraft and pendulum are assumed to be in states of steady spin about the symmetry axis of the spacecraft and the coupled time-varying nonlinear equation of the pendulum is simplified. A quasi-stationary solution to that equation and approximate resonance conditions are determined in terms of the system parameters. The analysis shows that the pendulum is subject to a combination of parametric and external-type excitation by the main body and that energy from the excited pendulum is fed into the main body to develop the coning instability. In this paper, numerical examples are presented to explain the mechanism of the coning angle growth and how angular momenta and disturbance moments are generated.

Piaget and the Pendulum

NASA Astrophysics Data System (ADS)

Bond, Trevor G.

Piaget's investigations into children's understanding of the laws governing the movement of a simple pendulum were first reported in 1955 as part of a report into how children's knowledge of the physical world changes during development. Chapter 4 of Inhelder & Piaget (1955/1958) entitled `The Oscillation of a Pendulum and the Operations of Exclusion'' demonstrated how adolescents could construct the experimental strategies necessary to isolate each of the variables, exclude the irrelevant factors and conclude concerning the causal role of length. This became one of the most easily replicable tasks from the Genevan school and was used in a number of important investigations to detect the onset of formal operational thinking. While it seems that the pendulum investigation fits nicely into Piaget's sequence of studies of concepts such as time, distance and speed suggested to him by Einstein, more recent research (Bond 2001) shows Inhelder to be directly responsible for the investigations into children's induction of physical laws. The inter-relationship between the pendulum problem, developing thought and scientific method is revealed in a number of Genevan and post-Piagetian investigations.

Ratchet baryogenesis and an analogy with the forced pendulum

NASA Astrophysics Data System (ADS)

Bamba, Kazuharu; Barrie, Neil D.; Sugamoto, Akio; Takeuchi, Tatsu; Yamashita, Kimiko

2018-06-01

A new scenario of baryogenesis via the ratchet mechanism is proposed based on an analogy with the forced pendulum. The oscillation of the inflaton field during the reheating epoch after inflation plays the role of the driving force, while the phase 𝜃 of a scalar baryon field (a complex scalar field with baryon number) plays the role of the angle of the pendulum. When the inflaton is coupled to the scalar baryon, the behavior of the phase 𝜃 can be analogous to that of the angle of the forced pendulum. If the oscillation of the driving force is adjusted to the pendulum’s motion, a directed rotation of the pendulum is obtained with a nonvanishing value of 𝜃˙, which models successful baryogenesis since 𝜃˙ is proportional to the baryon number density. Similar ratchet models which lead to directed motion have been used in the study of molecular motors in biology. There, the driving force is supplied by chemical reactions, while in our scenario this role is played by the inflaton during the reheating epoch.

Syntectonic Fluid-Rock Interactions Involving Surficial Waters in the Sevier Thrust Belt, Tendoy Mountains, Southwest Montana

NASA Astrophysics Data System (ADS)

Johnson, A. C.; Anastasio, D. J.; Bebout, G. E.

2002-05-01

Calcite veins and Mississippian carbonates from the Sevier thrust front record syntectonic meteoric fluid infiltration and hydrocarbon migration. The Tendoy and Four Eyes Canyon thrust sheets were emplaced onto the western margin of the Late Cretaceous Western Interior Seaway \\{WIS\\}. Low salinity \\{Tice = -0.6° C to +3.6° C\\} and low temperature \\{110° C +/- 10\\} fluids interacted with hanging-wall carbonates at a depth of 5km. Most veins have single or multiple generations of varying apertures, composed predominately of large euhedral crystals with some finer grained layers and protolith inclusions. Orientation analysis of mutually cross-cutting, high-angle vein sets suggest development concurrent with Four Eyes Canyon thrusting but prior to Tendoy thrusting. These vein sets are generally cut by later synfolding bed-parallel shear veins. Reactivation of both the bed-parallel and bed-perpendicular vein sets \\{strike parallel and strike perpendicular\\} in the Four Eyes Canyon thrust sheet occurred subsequent to Sevier compression, creating wide, coarse crystalline veins that often transect Sevier structures. Oxygen and Carbon isotope analyses of veins allow for reconstruction of fluid-rock interactions during thrust sheet emplacement and later reactivation. All veins and variably deformed host-rocks were microsampled and analyzed for δ 18OV-SMOW and δ 13CV-PDB. Small Tendoy veins \\{1mm-1cm wide\\} have calcite δ 18O values of +8.9 to +28.8‰ and calculated fluid \\{as H2O\\} of -8.3 to +11.6‰ \\{100° C\\}, -7.3 to +12.6‰ \\{110° C\\}, and -6.3 to +13.6‰ \\{120° C\\}. Four Eyes Canyon veins \\{1cm-3m wide\\} have calcite δ 18O values of +5.9 to +17.0‰ and calculated fluid of -11.3 to -0.2‰ \\{100° C\\}, -10.3 to +0.8‰ \\{110° C\\}, and -9.3 to +1.8‰ \\{120° C\\}. While there is significant variation in δ 18O there is relatively little systematic variation seen in δ 13C. Protolith carbonate has δ 18O values of +22.2‰ +/- 3.2; and some multi-layered veins are more depleted in δ 18O in earlier-formed generations. For three sites in the Lost River Range \\{LRR\\}, Idaho, the calculated minimum fluid δ 18O is -7.5‰ \\{+150 to +250° C\\} \\{Bebout et al., 2001; GRL\\}. Although the uncertainty of the regional temperature is large, when assuming a temperature of 110° C +/- 10 the Tendoy has a minimum calculated δ 18O H2O value of -8.3 to -6.3‰ and the Four Eyes Canyon has a minimum calculated δ 18O H2O value of -11.3 to -9.3‰ . These fluid O-isotope compositions are similar to the minimum H2O δ 18O calculated for the LRR sites - all pointing to infiltration of the thrust sheets by meteoric waters, possibly relatively nearshore meteoric waters with isotopic compositions strongly influenced by the nearby WIS. Surficial fluids possibly infiltrated into the thrust sheets by topographic recharge and migrated updip towards the foreland, mixing to varying degrees with more deeply roused fluids. Smaller veins and longer travel times and distances favored more extensive fluid-rock interaction and thus more rock-controlled fluid compositions. Microfractures in veins healed by hydrocarbons indicate that hydrocarbons migrated with freshwater fluids. Calcite veins record a dynamic history of fluid pathways and fluid flow as permeability evolved during thrust emplacement.

Geologic map of the Yucca Mountain region, Nye County, Nevada

USGS Publications Warehouse

Potter, Christopher J.; Dickerson, Robert P.; Sweetkind, Donald S.; Drake II, Ronald M.; Taylor, Emily M.; Fridrich, Christopher J.; San Juan, Carma A.; Day, Warren C.

2002-01-01

Yucca Mountain, Nye County, Nev., has been identified as a potential site for underground storage of high-level radioactive waste. This geologic map compilation, including all of Yucca Mountain and Crater Flat, most of the Calico Hills, western Jackass Flats, Little Skull Mountain, the Striped Hills, the Skeleton Hills, and the northeastern Amargosa Desert, portrays the geologic framework for a saturated-zone hydrologic flow model of the Yucca Mountain site. Key geologic features shown on the geologic map and accompanying cross sections include: (1) exposures of Proterozoic through Devonian strata inferred to have been deformed by regional thrust faulting and folding, in the Skeleton Hills, Striped Hills, and Amargosa Desert near Big Dune; (2) folded and thrust-faulted Devonian and Mississippian strata, unconformably overlain by Miocene tuffs and lavas and cut by complex Neogene fault patterns, in the Calico Hills; (3) the Claim Canyon caldera, a segment of which is exposed north of Yucca Mountain and Crater Flat; (4) thick densely welded to nonwelded ash-flow sheets of the Miocene southwest Nevada volcanic field exposed in normal-fault-bounded blocks at Yucca Mountain; (5) upper Tertiary and Quaternary basaltic cinder cones and lava flows in Crater Flat and at southernmost Yucca Mountain; and (6) broad basins covered by Quaternary and upper Tertiary surficial deposits in Jackass Flats, Crater Flat, and the northeastern Amargosa Desert, beneath which Neogene normal and strike-slip faults are inferred to be present on the basis of geophysical data and geologic map patterns. A regional thrust belt of late Paleozoic or Mesozoic age affected all pre-Tertiary rocks in the region; main thrust faults, not exposed in the map area, are interpreted to underlie the map area in an arcuate pattern, striking north, northeast, and east. The predominant vergence of thrust faults exposed elsewhere in the region, including the Belted Range and Specter Range thrusts, was to the east, southeast, and south. The vertical to overturned strata of the Striped Hills are hypothesized to result from successive stacking of three south-vergent thrust ramps, the lowest of which is the Specter Range thrust. The CP thrust is interpreted as a north-vergent backthrust that may have been roughly contemporaneous with the Belted Range and Specter Range thrusts. The southwest Nevada volcanic field consists predominantly of a series of silicic tuffs and lava flows ranging in age from 15 to 8 Ma. The map area is in the southwestern quadrant of the southwest Nevada volcanic field, just south of the Timber Mountain caldera complex. The Claim Canyon caldera, exposed in the northern part of the map area, contains thick deposits of the 12.7-Ma Tiva Canyon Tuff, along with widespread megabreccia deposits of similar age, and subordinate thick exposures of other 12.8- to 12.7-Ma Paintbrush Group rocks. An irregular, blocky fault array, which affects parts of the caldera and much of the nearby area, includes several large-displacement, steeply dipping faults that strike radially to the caldera and bound south-dipping blocks of volcanic rock. South and southeast of the Claim Canyon caldera, in the area that includes Yucca Mountain, the Neogene fault pattern is dominated by closely spaced, north-northwest- to north-northeast-striking normal faults that lie within a north-trending graben. This 20- to 25-km-wide graben includes Crater Flat, Yucca Mountain, and Fortymile Wash, and is bounded on the east by the 'gravity fault' and on the west by the Bare Mountain fault. Both of these faults separate Proterozoic and Paleozoic sedimentary rocks in their footwalls from Miocene volcanic rocks in their hanging walls. Stratigraphic and structural relations at Yucca Mountain demonstrate that block-bounding faults were active before and during eruption of the 12.8- to 12.7-Ma Paintbrush Group, and significant motion on these faults continued unt

Suicidal Decapitation by Hanging-A Population-based Study.

PubMed

Byard, Roger W; Gilbert, John D

2018-05-01

A prospective study was undertaken at Forensic Science SA over a 15-year period from July 2002 to June 2017 for all cases of adult (>18 years) suicidal hangings with decapitation. A total of 1446 cases of suicidal hangings were identified from a general population of approximately 1.5 million (1206 males-age range 18-97 years, average 42.6; and 240 females-age range 18-96 years, average 40.1). Only three cases of decapitation were found, all from long-drop hangings; these consisted of three males (ages 32-55 years; average 45 years). Spinal transections had occurred between the first and second, second and third, and third and fourth cervical vertebrae, respectively. In this study, the number of suicidal hangings with decapitation represented only 0.2% of the total number of hangings. These events are therefore extremely rare, most likely due to most suicidal hangings occurring from relatively low levels in a domestic environment. © 2017 American Academy of Forensic Sciences.

Hands Tied with Bag Full of Books in Suicidal Hanging.

PubMed

Sikary, Asit Kumar; Behera, Chittaranjan; Murty, Om Prakash; Rautji, Ravi

2016-01-01

Hanging deaths associated with binding of limbs, masking of a face, and gagging are always suspicious. In suicidal hanging, the victim uses these added techniques to prevent him from backing out of his decision and to ensure death. However, binding of limbs and adding extra weight to the suspension in hanging are not reported. Herein, we report a case where the victim tied a bag containing books weighing 7 kg (15.4 lbs) to both his hands during hanging. The forensic specialist must be aware of the unusual presentation of suicidal hanging which may suggest foul play. The manner of death must be established after detailed analysis of circumstantial evidence, information obtained from the witnesses, complete autopsy, and toxicological examination. © 2015 American Academy of Forensic Sciences.

The sympathy of two pendulum clocks: beyond Huygens' observations.

PubMed

Peña Ramirez, Jonatan; Olvera, Luis Alberto; Nijmeijer, Henk; Alvarez, Joaquin

2016-03-29

This paper introduces a modern version of the classical Huygens' experiment on synchronization of pendulum clocks. The version presented here consists of two monumental pendulum clocks--ad hoc designed and fabricated--which are coupled through a wooden structure. It is demonstrated that the coupled clocks exhibit 'sympathetic' motion, i.e. the pendula of the clocks oscillate in consonance and in the same direction. Interestingly, when the clocks are synchronized, the common oscillation frequency decreases, i.e. the clocks become slow and inaccurate. In order to rigorously explain these findings, a mathematical model for the coupled clocks is obtained by using well-established physical and mechanical laws and likewise, a theoretical analysis is conducted. Ultimately, the sympathy of two monumental pendulum clocks, interacting via a flexible coupling structure, is experimentally, numerically, and analytically demonstrated.

Parametric pendulum based wave energy converter

NASA Astrophysics Data System (ADS)

Yurchenko, Daniil; Alevras, Panagiotis

2018-01-01

The paper investigates the dynamics of a novel wave energy converter based on the parametrically excited pendulum. The herein developed concept of the parametric pendulum allows reducing the influence of the gravity force thereby significantly improving the device performance at a regular sea state, which could not be achieved in the earlier proposed original point-absorber design. The suggested design of a wave energy converter achieves a dominant rotational motion without any additional mechanisms, like a gearbox, or any active control involvement. Presented numerical results of deterministic and stochastic modeling clearly reflect the advantage of the proposed design. A set of experimental results confirms the numerical findings and validates the new design of a parametric pendulum based wave energy converter. Power harvesting potential of the novel device is also presented.

Change in stress with seismic cycles identified at an out of sequence thrust in an on-land accretionary complex: The Nobeoka thrust, Shimanto Belt, Kyusyu, SW Japan

NASA Astrophysics Data System (ADS)

Yamaguchi, M.; Hashimoto, Y.; Yamaguchi, A.; Kimura, G.

2011-12-01

Seismic surveys along accretionary prisms have revealed that the out-of sequence thrusts (OSTs) are commonly developed within accretionary wedges branching from seismogenic subduction plate boundaries. The OSTs are also recognized in on-land accretionary complexes as large thrust faults cutting paleo-thermal structures. The OSTs are thought to play a role in tsunami genesis at a coseismic event. Stress history on OSTs is significant to understand the OSTs' role in seismic cycles. We estimated, thus palaeostresses from micro-faults along an OST in an on-land accretionary complexes. We focused on the Nobeoka fault which is an OST in an on-land accretionary complex, the Shimato Belt, Kyusyu, SW Japan. A gap in paleothermal temperature (up to 70 degree C) is observed at the fault. The Nobeoka thrust strikes almost EW at coastline. The Cretaceous Makimine formation and Paleogene Kitagawa formation are located at the hanging wall of the fault, comprising mainly of pelitic schist. The footwall of the fault is the Paleogene Hyuga formation composed mainly of shale. A lot of micro-faults are well developed just below the thrust for a few hundred meters to the south. Those micro faults are considered to be related to the Nobeoka thurst because slip direction and sense of the micro-faults are consistent with that of the Nobeoka thrust. The micro-faults are commonly accompanied by mineral veins of quartz and ankerite. Yamaguchi et al. (2010) suggested that the differences of mineral veins are possibly related to the seismic cycle. In this study, we conducted stress inversion analysis for the micro-faults to examine the change in stress between them, which might be related to the seismic cycle. We divided the micro-fault into two as a micro-fault with quartz veins and that with ankerite veins. Slip direction from slicken fibers and slip sense by slicken steps were obtained. HIM (hough inversion method) by Yamaji et al. (2006) was used to estimate the stress. Two stress states and three stress states are identified in the results for ankerite veins and quartz veins, respectively. For ankerite veins, SE oriented and relatively higher dipping sigma3 with axial extension and SE oriented and relatively lower dipping sigma1 with axial compression are recognized. For quartz veins, SE oriented and relatively higher dipping sigma3 with axial extension, NE oriented and almost horizontal sigma1 with triaxial stress ratio, and NW oriented and lower dipping sigma1 with axial compression are observed. While NW-SE axial stress states are observed both from ankelite and quatz veins, NE oriented triaxial stress is identified only from quartz veins. The change in stress states from NW-SE axial stress to NE triaxial stress might be explained by the dynamic Coulomb wedge model suggested by Wang and Hu (2006). The model predicts that the stress within accretionary wedge can be change with seismic cycle, horizontal sigma1 with axial compression at the co-seismic slip and relatively higher dipping sigma1 with triaxial stress in inter-seimsic period.

Imaging Water in Deformed Quartzites: Examples from Caledonian and Himalayan Shear Zones

NASA Astrophysics Data System (ADS)

Kronenberg, Andreas; Ashley, Kyle; Hasnan, Hasnor; Holyoke, Caleb; Jezek, Lynna; Law, Richard; Thomas, Jay

2016-04-01

Infrared IR measurements of OH absorption bands due to water in deformed quartz grains have been collected from major shear zones of the Caledonian and Himalayan orogens. Mean intragranular water contents were determined from the magnitude of the broad OH absorption at 3400 cm-1 as a function of structural position, averaging over multiple grains, using an IR microscope coupled to a conventional FTIR spectrometer with apertures of 50-100 μm. Images of water content were generated by scanning areas of up to 4 mm2 of individual specimens with a 10 μm synchrotron-generated IR beam and contouring OH absorptions. Water contents vary with structural level relative to the central cores of shear zones and they vary at the grain scale corresponding to deformation and recrystallization microstructures. Gradients in quartz water content expressed over structural distances of 10 to 400 m from the centers of the Moine Thrust (Stack of Glencoul, NW Scotland), the Main Central Thrust (Sutlej valley of NW India), and the South Tibetan Detachment System (Rongbuk valley north of Mount Everest) indicate that these shear zones functioned as fluid conduits. However, the gradients differ substantially: in some cases, enhanced fluid fluxes appear to have increased quartz water contents, while in others, they served to decrease water contents. Water contents of Moine thrust quartzites appear to have been reduced during shear at greenschist facies by processes of regime II BLG/SGR dislocation creep. Intragranular water contents of the protolith 70 m below the central fault core are large (4078 ± 247 ppm, H/106 Si) while mylonites within 5 mm of the Moine hanging wall rocks have water contents of only 1570 (± 229) ppm. Water contents between these extremes vary systematically with structural level and correlate inversely with the extent of dynamic recrystallization (20 to 100%). Quartz intragranular water contents of Himalayan thrust and low-angle detachment zones sheared at upper amphibolite conditions by regime III GBM creep show varying trends with structural level. Water contents increase toward the Lhotse detachment of the Rongbuk valley, reaching 11,350 (± 1095) ppm, whereas they decrease toward the Main Central Thrust exposed in the western part of the Sutlej valley to values as low as 170 (± 25) ppm. Maps of intragranular water content correspond to populations of fluid inclusions, which depend on the history of deformation and dynamic recrystallization. Increases in water content require the introduction of secondary fluid inclusions, generally by brittle microcracking followed by crack healing and processes of inclusion redistribution documented in milky quartz experiments. Decreases in water content result from dynamic recrystallization, as mobile grain boundaries sweep through wet porphyroclasts, leaving behind dry recrystallized grains. Intragranular water contents throughout greenschist mylonites of the Moine thrust are comparable to those of quartz weakened by water in laboratory experiments. However, water contents of upper amphibolite mylonites of the Main Central Thrust are far below those required for water weakening at experimental strain rates and offer challenges to our understanding of quartz rheology.

Earthquake Facts

MedlinePlus

... recordings of large earthquakes, scientists built large spring-pendulum seismometers in an attempt to record the long- ... are moving away from one another. The first “pendulum seismoscope” to measure the shaking of the ground ...

Stability of controlled inverted pendulum under permanent horizontal perturbations of the supporting point

NASA Astrophysics Data System (ADS)

Aleksandrov, V. V.; Reyes-Romero, M.; Sidorenko, G. Yu.; Temoltzi-Auila, R.

2010-04-01

We consider the problem of choosing a test perturbation of a movable foundation of a single-link inverted pendulum so as to test a vestibular prosthesis prototype located at the top of this pendulum in an extreme situation. The obtained results permit concluding that the information transmitted from otolithic organs of the human vestibular system to muscles of the locomotor apparatus is very important and improves the quality of stabilization of the human vertical posture preventing the possible fall.

11. BUILDING NO. 620B. INTERIOR VIEW LOOKING NORTH, SHOWING PENDULUM ...

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

11. BUILDING NO. 620-B. INTERIOR VIEW LOOKING NORTH, SHOWING PENDULUM AND FRAME IN FOREGROUND, SHIELD FOR OPERATORS IN BACKGROUND. FRICTION TEST IS OBSERVED FROM BEHIND BLAST SHIELD BY A SERIES OF MIRRORS. ANVIL IN CENTER OF PENDULUM FRAME HOLDS EXPLOSIVE WHOSE SENSITIVITY TO FRICTION IS TO BE TESTED. PANS ON EITHER SIDE CATCH ANY UNBURNT EXPLOSIVE SLUNG FROM ANVIL DURING TEST TO PREVENT EXPLOSIVE HAZARD. - Picatinny Arsenal, 600 Area, Test Areas District, State Route 15 near I-80, Dover, Morris County, NJ

Dynamic Accuracy of Inertial Magnetic Sensor Modules

DTIC Science & Technology

2016-12-01

and the cost of the YEI 3-space data-logging sensor was justified. C. PREVIOUS WORK In [7], Jeremy Cookson built a low-cost pendulum with an optical...encoder to test the dynamic accuracy of MARG sensor modules. The pendulum was designed in order to execute dynamic, repeatable tests in a single...3DM-GX1 and 3DM-GX3-25 sensors. In [8], Leslie Landry developed similar repeatable tests and utilized the pendulum to test the dynamic accuracy of

Advancements of In-Flight Mass Moment of Inertia and Structural Deflection Algorithms for Satellite Attitude Simulators

DTIC Science & Technology

2015-03-26

pendulum [15] to estimate the MOI. The benefit to this methodology is that instead of a direct comparison to Euler’s equations when using an on-board ACS...the equations of motion of pendulum motion are evaluated to estimate the resistance to angular acceleration. Instead of attempting to compare noisy...sensor data instantaneously when using on-board ACS data, the pendulum oscillation frequency is estimated, which can be globally smoothed for highly

Integrated Reconfigurable Intelligent Systems (IRIS) for Complex Naval Systems

DTIC Science & Technology

2011-02-23

INTRODUCTION 35 2.2 GENERAL MODEL SETUP 36 2.2.1 Co-Simulation Principles 36 2.2.2 Double pendulum : a simple example 38 2.2.3 Description of numerical... pendulum sample problem 45 2.3 DISCUSSION OF APPROACH WITH RESPECT TO PROPOSED SUBTASKS 49 2.4 RESULTS DISCUSSION AND FUTURE WORK 49 TASK 3...Kim and Praehofer 2000]. 2.2.2 Double pendulum : a simple example In order to be able to evaluate co-simulation principles, specifically an

Measuring g Using a Magnetic Pendulum and Telephone Pickup

NASA Astrophysics Data System (ADS)

Sinacore, J.; Takai, H.

2010-10-01

The simple pendulum has long been used to measure g, the acceleration due to gravity, with a precision of a few percent. Achieving agreement with the accepted value of less than 1% is feasible in the high school laboratory, though it requires some care. The precision of the measurement is bound by how accurately the period and the pendulum length are determined. To improve on the period measurement, we have developed a simple and inexpensive method using a magnet and telephone pickup.2

Re-evaluation of P-T paths across the Himalayan Main Central Thrust

NASA Astrophysics Data System (ADS)

Catlos, E. J.; Harrison, M.; Kelly, E. D.; Ashley, K.; Lovera, O. M.; Etzel, T.; Lizzadro-McPherson, D. J.

2016-12-01

The Main Central Thrust (MCT) is the dominant crustal thickening structure in the Himalayas, juxtaposing high-grade Greater Himalayan Crystalline rocks over the lower-grade Lesser Himalaya Formations. The fault is underlain by a 2 to 12-km-thick sequence of deformed rocks characterized by an apparent inverted metamorphic gradient, termed the MCT shear zone. Garnet-bearing rocks sampled from across the MCT along the Marysandi River in central Nepal contain monazite that decrease in age from Early Miocene (ca. 20 Ma) in the hanging wall to Late Miocene-Pliocene (ca. 7 Ma and 3 Ma) towards structurally lower levels in the shear zone. We obtained high-resolution garnet-zoning pressure-temperature (P-T) paths from 11 of the same rocks used for monazite geochronology using a recently-developed semi-automated Gibbs-free-energy-minimization technique. Quartz-in-garnet Raman barometry refined the locations of the paths. Diffusional re-equilibration of garnet zoning in hanging wall samples prevented accurate path determinations from most Greater Himalayan Crystalline samples, but one that shows a bell-shaped Mn zoning profile shows a slight decrease in P (from 8.2 to 7.6kbar) with increase in T (from 590 to 640ºC). Three MCT shear zone samples were modeled: one yields a simple path increasing in both P and T (6 to 7kbar, 540 to 580ºC); the others yield N-shaped paths that occupy similar P-T space (4 to 5.5 kbar, 500 to 560ºC). Five lower lesser Himalaya garnet-bearing rocks were modeled. One yields a path increasing in both P-T (6 to 7 kbar, 525 to 550ºC) but others show either sharp compression/decompression or N-shape paths (within 4.5-6 kbar and 530-580ºC). The lowermost sample decreases in P (5.5 to 5 kbar) over increasing T (540 to 580°C). No progressive change is seen from one type of path to another within the Lesser Himalayan Formations to the MCT zone. The results using the modeling approach yield lower P-T conditions compared to the Gibbs method and lower core/rim P-T conditions compared to traditional thermometers and barometers. Inclusion barometry suggests that baric estimates from the modeling may be underestimated by 2-4 kbar. Despite uncertainty, path shapes are consistent with a model in which the MCT shear zone experienced a progressive accretion of footwall slivers.

Evaluation of Vitality in the Experimental Hanging Model of Rats by Using Immunohistochemical IL-1β Antibody Staining.

PubMed

Balandiz, Hüseyin; Pehlivan, Sultan; Çiçek, Ali Fuat; Tuğcu, Harun

2015-12-01

Hanging is the most common suicide method in the world, and the discrimination of antemortem-postmortem hanging must be done at autopsy. The aim of this experimental study was to examine the immunohistochemical expression of IL-1β antibody at the hanging mark skin samples of rats to discriminate antemortem and postmortem hangings. A total of 20 Wistar albino rats were used for this study. The groups were as follows: A-1, antemortem control group; A-2, antemortem second-hour hanging mark skin samples; A-3, antemortem 24th-hour hanging mark skin samples; A-4, antemortem 72nd-hour hanging mark skin samples; B-1, postmortem control group; and B-2, postmortem second-hour hanging mark skin samples. Interleukin-1β immunostaining was performed to all tissue samples. For epidermal cells, group A-1 samples did not show IL-1β immunostaining, group A-2 samples were severely immunostained, and groups A-3 and A-4 samples' staining were slightly decreased. There was no IL-1β antibody staining in groups B-1 and B-2 samples. For adnexal cells, groups A-1 and B-1 samples did not show IL-1β immunostaining, staining of group A-2 samples was mild to severe, and groups A-3 and A-4 samples' staining were slightly decreased. Half of the group B-2 samples did not show IL-1β immunostaining. For subepidermal cells, most of the samples of groups A-1 and B-1 showed slight immunostaining, groups A-2 and B-2 samples' staining were mild to severe, and there were slight immunostaining in groups A-3 and A-4 samples. The majority of vascular structure cells did not show IL-1β immunostaining. Interleukin-1β immunostaining of epidermal cells can discriminate antemortem-postmortem hangings, but vascular structure cells and subepidermal cells cannot discriminate vital hangings.

State Estimation for Humanoid Robots

DTIC Science & Technology

2015-07-01

21 2.2.1 Linear Inverted Pendulum Model . . . . . . . . . . . . . . . . . . . 21 2.2.2 Planar Five-link Model...Linear Inverted Pendulum Model. LVDT Linear Variable Differential Transformers. MEMS Microelectromechanical Systems. MHE Moving Horizon Estimator. QP...

Changes in stature following plyometric drop-jump and pendulum exercises.

PubMed

Fowler, N E; Lees, A; Reilly, T

1997-12-01

The aim of this study was to compare the changes in stature following the performance of plyometric exercises using drop-jumps and a pendulum swing. Eight male participants aged 21.7 +/- 1.8 years with experience of plyometric training gave their informed consent to act as participants. Participants undertook two exercise regimens and a 15-min standing test in a random order. The exercises entailed the performance of 50 drop-jumps from a height of 0.28 m or 50 pendulum rebounds. Participants were instructed to perform maximal jumps or rebounds using a 'bounce' style. Measurements of stature were performed after a 20-min period of standing (pre-exercise), 2-min after exercise (post-exercise) and after a 20-min standing recovery (recovery). Back pain and muscle soreness were assessed using an analogue-visual scale, at each of the above times and also 24 and 36 h after the test. Peak torque during isokinetic knee extension at 1.04 rads-1 was measured immediately before and after the exercise bouts, to assess the degree of muscular fatigue. Ground/wall reaction force data were recorded using a Kistler force platform mounted in the floor for drop-jumps and vertically on the rebound wall for pendulum exercises. Drop-jumps resulted in the greatest (p < 0.05) change in stature (-2.71 +/- 0.8 mm), compared to pendulum exercises (-1.77 +/- 0.7 mm) and standing (-0.39 +/- 0.2 mm). Both exercise regimens resulted in a significant (p < 0.01) decrease in stature when compared to the standing condition. Drop-jumps resulted in significantly greater peak impact forces (p < 0.05) than pendulum exercises (drop-jumps = 3.2 +/- 0.5 x body weight, pendulum = 2.6 +/- 0.5 x body weight). The two exercise conditions both invoked a small degree of muscle soreness but there were no significant differences between conditions. Both exercise regimens resulted in a non-significant decrease in peak torque indicating a similar degree of muscular fatigue. Based on the lower shrinkage resulted and lower peak forces, it can be concluded that pendulum exercises pose a lower injury potential to the lower back than drop-jumps performed from a height of 28 cm.

49 CFR 572.127 - Test conditions and instrumentation.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Forces—Class 1000; (ii) Moments—Class 600; (iii) Pendulum acceleration—Class 180; (iv) Rotation—Class 60 (if used). (3) Thorax: (i) Rib acceleration—Class 1000; (ii) Spine and pendulum accelerations—Class...

49 CFR 572.127 - Test conditions and instrumentation.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Forces—Class 1000; (ii) Moments—Class 600; (iii) Pendulum acceleration—Class 180; (iv) Rotation—Class 60 (if used). (3) Thorax: (i) Rib acceleration—Class 1000; (ii) Spine and pendulum accelerations—Class...

49 CFR 572.127 - Test conditions and instrumentation.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Forces—Class 1000; (ii) Moments—Class 600; (iii) Pendulum acceleration—Class 180; (iv) Rotation—Class 60 (if used). (3) Thorax: (i) Rib acceleration—Class 1000; (ii) Spine and pendulum accelerations—Class...

49 CFR 572.127 - Test conditions and instrumentation.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Forces—Class 1000; (ii) Moments—Class 600; (iii) Pendulum acceleration—Class 180; (iv) Rotation—Class 60 (if used). (3) Thorax: (i) Rib acceleration—Class 1000; (ii) Spine and pendulum accelerations—Class...

49 CFR 572.127 - Test conditions and instrumentation.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Forces—Class 1000; (ii) Moments—Class 600; (iii) Pendulum acceleration—Class 180; (iv) Rotation—Class 60 (if used). (3) Thorax: (i) Rib acceleration—Class 1000; (ii) Spine and pendulum accelerations—Class...

Co-seismic thermal dissociation of carbonate fault rocks: Naukluft Thrust, central Namibia

NASA Astrophysics Data System (ADS)

Rowe, C. D.; Miller, J. A.; Sylvester, F.; Backeberg, N.; Faber, C.; Mapani, B.

2009-12-01

Frictional heating has been shown to dissociate carbonate minerals in fault rocks and rock slides at high velocities, producing in-situ fluid pressure spikes and resulting in very low effective friction. We describe the textural and geochemical effects of repeated events of frictional-thermal dissociation and fluidization along a low-angle continental thrust fault. The Naukluft Thrust in central Namibia is a regional décollement along which the Naukluft Nappe Complex was emplaced over the Nama Basin in the southern foreland of the ~ 550Ma Damara Orogen. Fault rocks in the thrust show a coupled geochemical and structural evolution driven by dolomitization reactions during fault activity and facilitated by fluid flow along the fault surface. The earliest developed fault rocks are calcite-rich calcmylonites which were progressively dolomitized along foliation. Above a critical dolomite/calcite ratio, the rocks show only brittle deformation fabrics dominated by breccias, cataclasites, and locally, a thin (1-3cm) microcrystalline, smooth white ultracataclasite. The fault is characterized by the prevalence of an unusual “gritty dolomite” yellow cataclasite containing very well rounded clasts in massive to flow-banded fine dolomitic matrix. This cataclasite, locally known as the “gritty dolomite”, may reach thicknesses of up to ~ 10m without evidence of internal cross-cutting relations with randomly distributed clasts (an “unsorted” texture). The gritty dolomite also forms clastic injections into the hanging wall of the fault, frequently where the fault surface changes orientation. Color-cathodoluminescence images show that individual carbonate grains within the “gritty dolomite” have multiple layers of thin (~10-100 micron) dolomite coatings and that the grains were smoothed and rounded between each episode of coating precipitation. Coated grains are in contact with one another but grain cores are never seen in contact. CL-bright red dolomite which forms the coatings is never observed as pore-fill between grains or other geometries typical of cement precipitates. Smoothness and radial symmetry of the coatings suggest that the grains were coated in suspension by very fine material, potentially analogous to the frictionally-generated CaO developed on the base of some landslides in carbonate rocks (Hewitt, 1988). The very thick layers of cataclasite without internal crosscutting suggest free particle paths associated with fluidization at high fluid pressure and low effective normal stress. We suggest that co-seismic frictional heating along the Naukluft Thrust caused dissociation of dolomite fault rock, producing in-situ spikes in fluid pressure (CO2) and very fine caustic CaO which chemically attacked the carbonate grains in suspension causing the smoothing and rounding. These residues then coated individual grains prior to loss of fluid pressure and settling in the fault zone. Such an event would have been associated with near total strength drop along the Naukluft Thrust. Hewitt, K., 1988 Science, v. 242, no. 4875, p. 64-67.

Suicidal hanging within an automobile.

PubMed

Blanco Pampin, J M; López-Abajo Rodriguez, B A

2001-12-01

Accidental asphyxia related to cars has been described in different reports, but suicidal hanging in an automobile is very unusual. Two cases of suicidal hanging inside an automobile are described, illustrating an unusual form of hanging. In one case, the deceased used his belt as a ligature, and the point of attachment was the window of the car. The second victim used the safety belt of the passenger seat. In both cases, the automobile engine was turned off, all the windows were closed, and the door locks were blocked. The medicolegal cause of hanging was based on the scene of the investigation, police and witness reports, social history, autopsy findings, and toxicologic examinations.

49 CFR 572.146 - Test conditions and instrumentation.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Head acceleration—Class 1000 (2) Neck (i) Force—Class 1000 (ii) Moments—Class 600 (iii) Pendulum... acceleration—Class 1000 (ii) Spine and pendulum accelerations—Class 180 (iii) Sternum deflection—Class 600 (iv...

49 CFR 572.155 - Test conditions and instrumentation.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Moments—Class 600; (iii) Pendulum acceleration—Class 180; (iv) Rotation potentiometer response (if used)—CFC 60. (3) Thorax: (i) Spine and pendulum accelerations—Class 180; (ii) Shoulder forces—Class 600; (4...

49 CFR 572.155 - Test conditions and instrumentation.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Moments—Class 600; (iii) Pendulum acceleration—Class 180; (iv) Rotation potentiometer response (if used)—CFC 60. (3) Thorax: (i) Spine and pendulum accelerations—Class 180; (ii) Shoulder forces—Class 600; (4...

49 CFR 572.177 - Test conditions and instrumentation.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) except as noted, with channel frequency classes as follows: (1) Pendulum acceleration, CFC 180, (2) Pendulum D-plane rotation (if transducer is used), CFC 60, (3) Torso flexion pulling force (if transducer...

49 CFR 572.177 - Test conditions and instrumentation.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) except as noted, with channel frequency classes as follows: (1) Pendulum acceleration, CFC 180, (2) Pendulum D-plane rotation (if transducer is used), CFC 60, (3) Torso flexion pulling force (if transducer...