Science.gov

Sample records for acceleration peak ground

  1. Relationships between peak ground acceleration, peak ground velocity, and modified mercalli intensity in California

    USGS Publications Warehouse

    Wald, D.J.; Quitoriano, V.; Heaton, T.H.; Kanamori, H.

    1999-01-01

    We have developed regression relationships between Modified Mercalli Intensity (Imm) and peak ground acceleration (PGA) and velocity (PGV) by comparing horizontal peak ground motions to observed intensities for eight significant California earthquakes. For the limited range of Modified Mercalli intensities (Imm), we find that for peak acceleration with V ??? Imm ??? VIII, Imm = 3.66 log(PGA) - 1.66, and for peak velocity with V ??? Imm ??? IX, Imm = 3.47 log(PGV) + 2.35. From comparison with observed intensity maps, we find that a combined regression based on peak velocity for intensity > VII and on peak acceleration for intensity < VII is most suitable for reproducing observed Imm patterns, consistent with high intensities being related to damage (proportional to ground velocity) and with lower intensities determined by felt accounts (most sensitive to higher-frequency ground acceleration). These new Imm relationships are significantly different from the Trifunac and Brady (1975) correlations, which have been used extensively in loss estimation.

  2. Estimation on Peak Ground Acceleration in Taiwan Area

    NASA Astrophysics Data System (ADS)

    Chen, K.

    2013-12-01

    Since the Taiwan area is situated on the subduction zone, where the Philippine Sea Plate is subducting underneath the Eurasian Plate, much attention is focused on seismic risk mitigation. The purpose of this paper is to study the potential of earthquakes hazard in the Taiwan area, using the seismic acceleration data collected by the Central Weather Bureau from 1993 to 2008. The theoretic Peak Ground Acceleration (PGA) is calculated basing on well developed velocity and attenuation models. The theoretic maximum amplitudes of the ground acceleration in Taiwan area for 30 events have been calculated by using the attenuation equation and the Q-structures. The deviations between the observed and theoretic PGA of 163 seismic stations in Taiwan area can be obtained. The results show that most of the deviation is small than 30%. It indicates that we can predict the maximum amplitude of ground acceleration for any events occurred in Taiwan area under the accuracy of 70 % (probability). The estimation of PGA for any earthquake will be obtained using the theoretic and corrected with these deviations.

  3. Bayesian Analysis of Peak Ground Acceleration Attenuation Relationship

    SciTech Connect

    Mu Heqing; Yuen Kaveng

    2010-05-21

    Estimation of peak ground acceleration is one of the main issues in civil and earthquake engineering practice. The Boore-Joyner-Fumal empirical formula is well known for this purpose. In this paper we propose to use the Bayesian probabilistic model class selection approach to obtain the most suitable prediction model class for the seismic attenuation formula. The optimal model class is robust in the sense that it has balance between the data fitting capability and the sensitivity to noise. A database of strong-motion records is utilized for the analysis. It turns out that the optimal model class is simpler than the full order attenuation model suggested by Boore, Joyner and Fumal (1993).

  4. Bayesian Estimations of Peak Ground Acceleration and 5% Damped Spectral Acceleration from Modified Mercalli Intensity Data

    USGS Publications Warehouse

    Ebel, J.E.; Wald, D.J.

    2003-01-01

    We describe a new probabilistic method that uses observations of modified Mercalli intensity (MMI) from past earthquakes to make quantitative estimates of ground shaking parameters (i.e., peak ground acceleration, peak ground velocity, 5% damped spectral acceleration values, etc.). The method uses a Bayesian approach to make quantitative estimates of the probabilities of different levels of ground motions from intensity data given an earthquake of known location and magnitude. The method utilizes probability distributions from an intensity/ground motion data set along with a ground motion attenuation relation to estimate the ground motion from intensity. The ground motions with the highest probabilities are the ones most likely experienced at the site of the MMI observation. We test the method using MMI/ground motion data from California and published ground motion attenuation relations to estimate the ground motions for several earthquakes: 1999 Hector Mine, California (M7.1); 1988 Saguenay, Quebec (M5.9); and 1982 Gaza, New Hampshire (M4.4). In an example where the method is applied to a historic earthquake, we estimate that the peak ground accelerations associated with the 1727 (M???5.2) earthquake at Newbury, Massachusetts, ranged from 0.23 g at Newbury to 0.06 g at Boston.

  5. Historic Seismicity, Computed Peak Ground Accelerations, and Seismic Site Conditions for Northeast Mexico

    NASA Astrophysics Data System (ADS)

    Montalvo-Arriet, J. C.; Galván-Ramírez, I. N.; Ramos-Zuñiga, L. G.; Navarro de León, I.; Ramírez-Fernández, J. A.; Quintanilla-López, Y.; Cavazos-Tovar, N. P.

    2007-05-01

    In this study we present the historic seismicity, computed peak ground accelerations, and mapping of seismic site conditions for northeast Mexico. We start with a compilation of the regional seismicity in northeast Mexico (24- 31°N, 87-106°W) for the 1787-2006 period. Our study area lies within three morphotectonic provinces: Basin and Range and Rio Grande rift, Sierra Madre Oriental and Gulf Coastal Plain. Peak ground acceleration (PGA) maps were computed for three different scenarios: 1928 Parral, Chihuahua (MW = 6.5); 1931 Valentine, Texas (MW = 6.4); and a hypothetical earthquake located in central Coahuila (MW = 6.5). Ground acceleration values were computed using attenuation relations developed for central and eastern North America and the Basin and Range province. The hypothetical earthquake in central Coahuila is considered a critical scenario for the main cities of northeast Mexico. The damage associated with this hypothetical earthquake could be severe because the majority of the buildings were constructed without allowance for seismic accelerations. The expected PGA values in Monterrey, Saltillo and Monclova range from 30 to 70 cm/s2 (0.03 to 0.07g). This earthquake might also produce or trigger significant landslides and rock falls in the Sierra Madre Oriental, where several cities are located (e.g. suburbs of Monterrey). Additionally, the Vs30 distribution for the state of Nuevo Leon and the cities of Linares and Monterrey are presented. The Vs30 data was obtained using seismic refraction profiling correlated with borehole information. According to NEHRP soil classification, sites classes A, B and C are dominant. Sites with class D occupy minor areas in both cities. Due to the semi-arid conditions in northeast Mexico, we obtained the highest values of Vs30 in Quaternary deposits (alluvium) cemented by caliche. Similar values of Vs30 were obtained in Reno and Las Vegas, Nevada. This work constitutes the first attempt at understanding and

  6. Uncertainty in the estimates of peak ground acceleration in seismic hazard analysis

    NASA Astrophysics Data System (ADS)

    Pavlenko, V. A.

    2015-11-01

    Probabilistic seismic hazard analysis has become a standard procedure preceding the antiseismic construction. An important component of the relevant calculations is the allowance for the uncertainty in the strong motion parameters (e.g., peak ground acceleration (PGA)). In the present-day approaches of probabilistic analysis, this uncertainty is modeled by a random variable (a residual) which has a lognormal distribution. With this model, the extrapolation into the area of long return periods yields nonzero probabilities of unrealistically high PGA. In the present work, the distribution of the logarithmic PGA residuals is modeled by different parametric distributions. From the set of these distributions, the one which provides the closest approximation of the empirical data is selected by the statistical criteria. The analysis shows that the generalized extreme value distribution (GEVD) most accurately reproduces the residuals of the logarithmic PGA, and the tail of the distribution is approximated by the generalized Pareto distribution (GPD).

  7. Teleseismic Peak Ground Accelerations from the 24 May 2013 Sea of Okhotsk Deep Earthquake

    NASA Astrophysics Data System (ADS)

    Kuge, K.

    2014-12-01

    The 2013 Sea of Okhotsk deep earthquake (Mw8.3) generated felt reports worldwide including ones from Moscow (~58 degrees) and Dubai (~76 degrees) (NEIC, 2013). The earthquake was recorded by many global seismic stations with a good coverage of azimuth and distance, which provides an opportunity to understand the global characteristics of ground shaking. Peak ground accelerations (PGA) from the Sea of Okhotsk deep earthquake decrease with distance up to 120 degrees, and have a peak at a distance of 140-150 degrees. The variation as a function of distance is similar to the one shown by Anderson et al. (1995) for the 1994 Bolivia earthquake. PGA at distances between 40 and 85 degrees are associated with vertical components of direct P waves, and the values are mostly in a range from 0.1 to 1 gal. The decay with distance is in agreement with that of P wave amplitude predicted by the ray theory with t* in the range between the lower-mantle attenuation models of Hwang and Ritsema (2011) and PREM. Frequencies characterizing the PGA decay are in a range between 0.8 and 1.8 Hz. As also suggested by observations from other large deep earthquakes, the radiation pattern of P waves can change the decay curves of PGA with distance, by affecting the amplitude of P waves in the frequency range. Spatial variations of PGA are likely to be characterized by the tectonic setting; large values of PGA appear in stable continents and old seas, whereas small values are observed in tectonically active regions. Positive correlation is observed between PGA values and velocity perturbations of the 3-D global shear velocity model at depths shallower than 100 km.

  8. Characteristics of Spatial Distribution for Peak Ground Acceleration in 3 Aug 2014 Ms6.5 Ludian Earthquake, Yuanan, China

    NASA Astrophysics Data System (ADS)

    kun, Chen; YanXiang, Yu

    2016-04-01

    Considering the geological context, focal mechanism solutions, aftershock distribution and attenuation characteristics of the ground motion in western China, shakemaps of PGA (Peak Ground Acceleration) for The Ludian Ms6.5 earthquake on 3 Aug 2014 was acquired, in which the Mothed of rapid generation ShakeMaps considering site effects was used, and the peak ground acceleration of 62 stations for this earthquake was used as interpolation. Then, distribution of PGA was amended by using PGA observations to correct system bias of theoretical estimates in the area without PGA observations. The results show that the attenuation of ground motion with distance for this earthquake was faster than that of Wang Su-Yun in 2000; the result of bias-corrected was more consistent with attenuation law of this earthquake. After adjusting, for the area with PGA greater than 40 cm / s2 was nearly 8000 km2, which was is reduced by about 40%.

  9. A New Ground Motion Intensity Measure, Peak Filtered Acceleration (PFA), to Estimate Collapse Vulnerability of Buildings in Earthquakes

    NASA Astrophysics Data System (ADS)

    Song, Shiyan

    In this thesis, we develop an efficient collapse prediction model, the PFA (Peak Filtered Acceleration) model, for buildings subjected to different types of ground motions. For the structural system, the PFA model covers modern steel and reinforced concrete moment-resisting frame buildings (potentially reinforced concrete shear wall buildings). For ground motions, the PFA model covers ramp-pulse-like ground motions, long-period ground motions, and short-period ground motions. To predict whether a building will collapse in response to a given ground motion, we first extract long-period components from the ground motion using a Butterworth low-pass filter with suggested order and cutoff frequency. The order depends on the type of ground motion, and the cutoff frequency depends on the building's natural frequency and ductility. We then compare the filtered acceleration time history with the capacity of the building. The capacity of the building is a constant for 2-dimentional buildings and a limit domain for 3-dimentional buildings. If the filtered acceleration exceeds the building's capacity, the building is predicted to collapse. Otherwise, it is expected to survive the ground motion. The parameters used in PFA model, which include fundamental period, global ductility and lateral capacity, can be obtained either from numerical analysis or interpolation based on the reference building system proposed in this thesis. The PFA collapse prediction model greatly reduces computational complexity while archiving good accuracy. It is verified by FEM simulations of 13 frame building models and 150 ground motion records. Based on the developed collapse prediction model, we propose to use PFA (Peak Filtered Acceleration) as a new ground motion intensity measure for collapse prediction. We compare PFA with traditional intensity measures PGA, PGV, PGD, and Sa in collapse prediction and find that PFA has the best performance among all the intensity measures. We also provide a

  10. Next Generation Attenuation of Ground Motions in Ilan, Taiwan: Establishment and Analysis of Attenuation Relations for Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV)

    NASA Astrophysics Data System (ADS)

    Liu, K.

    2009-12-01

    An evaluation of seismic hazards requires an estimate of the expected ground motion at the site of interest. The most common means of estimating this ground motion in engineering practice is the use of an attenuation relation. A number of developments have arisen recently to suggest that a new generation of attenuation relationships is warranted. The project named Next Generation Attenuation of Ground Motions (NGA) Project was developed by Pacific Earthquake Engineering Research Center (PEER) in response to a core objective: reducing uncertainty in earthquake ground motion estimation. This objective reflects recognition from industry sponsors that improvements in earthquake ground motion estimation will result in significant cost savings and will result in improved system performance in the event of a large earthquake. The Central Weather Bureau has implemented the Taiwan Strong Motion Instrumentation Program (TSMIP) to collect high-quality instrumental recordings of strong earthquake shaking.It is necessary for us to study the strong ground motion characteristics at the Ilan area of northeastern Taiwan. Further analyses using a good quality data base that includes 486 events and 4172 recordings of magnitude greater than 4.0 are required to derive the next generation attenuation of ground motion in Ilan area. In addition, Liu and Tsai (2007) used a catalog of more than 1840 shallow earthquakes with homogenized Mw magnitude ranging from 5.0 to 8.2 in 1900-2007 to estimate the seismic hazard potential in Taiwan. As a result, the PGA and PGV contour patterns of maximum ground motion show that Ilan Plain has high values of 0.2g and 80cm/sec with respect to MMI intensity VII and IX, respectively. Furthermore, from the mean ground motion and the seismic intensity rate analyses, they show that a high annul probability of MMI > VI greater than 35 percents are located at the Chianan area of western Taiwan and Ilan Plain in northeastern Taiwan. However, these results was

  11. Estimation of Peak Ground Acceleration (PGA) for Peninsular Malaysia using geospatial approach

    NASA Astrophysics Data System (ADS)

    Nouri Manafizad, Amir; Pradhan, Biswajeet; Abdullahi, Saleh

    2016-06-01

    Among the various types of natural disasters, earthquake is considered as one of the most destructive events which impose a great amount of human fatalities and economic losses. Visualization of earthquake events and estimation of peak ground motions provides a strong tool for scientists and authorities to predict and mitigate the aftereffects of earthquakes. In addition it is useful for some businesses like insurance companies to evaluate the amount of investing risk. Although Peninsular Malaysian is situated in the stable part of Sunda plate, it is seismically influenced by very active earthquake sources of Sumatra's fault and subduction zones. This study modelled the seismic zones and estimates maximum credible earthquake (MCE) based on classified data for period 1900 to 2014. The deterministic approach was implemented for the analysis. Attenuation equations were used for two zones. Results show that, the PGA produced from subduction zone is from 2-64 (gal) and from the fault zone varies from 1-191(gal). In addition, the PGA generated from fault zone is more critical than subduction zone for selected seismic model.

  12. Preliminary map of peak horizontal ground acceleration for the Hanshin-Awaji earthquake of January 17, 1995, Japan - Description of Mapped Data Sets

    USGS Publications Warehouse

    Borcherdt, R.D.; Mark, R.K.

    1995-01-01

    The Hanshin-Awaji earthquake (also known as the Hyogo-ken Nanbu and the Great Hanshin earthquake) provided an unprecedented set of measurements of strong ground shaking. The measurements constitute the most comprehensive set of strong- motion recordings yet obtained for sites underlain by soft soil deposits of Holocene age within a few kilometers of the crustal rupture zone. The recordings, obtained on or near many important structures, provide an important new empirical data set for evaluating input ground motion levels and site amplification factors for codes and site-specific design procedures world wide. This report describes the data used to prepare a preliminary map summarizing the strong motion data in relation to seismicity and underlying geology (Wentworth, Borcherdt, and Mark., 1995; Figure 1, hereafter referred to as Figure 1/I). The map shows station locations, peak acceleration values, and generalized acceleration contours superimposed on pertinent seismicity and the geologic map of Japan. The map (Figure 1/I) indicates a zone of high acceleration with ground motions throughout the zone greater than 400 gal and locally greater than 800 gal. This zone encompasses the area of most intense damage mapped as JMA intensity level 7, which extends through Kobe City. The zone of most intense damage is parallel, but displaced slightly from the surface projection of the crustal rupture zone implied by aftershock locations. The zone is underlain by soft-soil deposits of Holocene age.

  13. A Spatial Correlation Model of Peak Ground Acceleration and Response Spectra Based on Data of the Istanbul Earthquake Rapid Response and Early Warning System

    NASA Astrophysics Data System (ADS)

    Wagener, Thomas; Goda, Katsuichiro; Erdik, Mustafa; Daniell, James; Wenzel, Friedemann

    2016-04-01

    Ground motion intensity measures such as the peak ground acceleration (PGA) and the pseudo spectral acceleration (PSA) at two sites due to the same seismic event are correlated. The spatial correlation needs to be considered when modelling ground-motion fields for seismic loss assessments, since it can have a significant influence on the statistical moments and probability distribution of aggregated seismic loss of a building portfolio. Empirical models of spatial correlation of ground motion intensity measures exist only for a few seismic regions in the world such as Japan, Taiwan and California, since for this purpose a dense observation network of earthquake ground motion is required. The Istanbul Earthquake Rapid Response and Early Warning System (IERREWS) provides one such dense array with station spacing of typically 2 km in the urban area of Istanbul. Based on the records of eight small to moderate (Mw3.5 - Mw5.1) events, which occurred since 2003 in the Marmara region, we establish a model of intra-event spatial correlation for PGA and PSA up to the natural period of 1.0 s. The results indicate that the correlation coefficients of PGA and short-period PSA decay rapidly with increasing interstation distance, resulting in correlation lengths of approximately 2-3 km, while correlation lengths at longer natural periods (above 0.5 s) exceed 5 km. Finally, we implement the correlation model in a Monte Carlo simulation to evaluate economic loss in Istanbul's district Zeytinburnu due to an Mw7.2 scenario earthquake.

  14. Stochastic acceleration in peaked spectrum

    SciTech Connect

    Zasenko, V.; Zagorodny, A.; Weiland, J.

    2005-06-15

    Diffusion in velocity space of test particles undergoing external random electric fields with spectra varying from low intensive and broad to high intensive and narrow (peaked) is considered. It is shown that to achieve consistency between simulation and prediction of the microscopic model, which is reduced to Fokker-Planck-type equation, it is necessary, in the case of peaked spectrum, to account for temporal variation of diffusion coefficient occurring in the early stage. An analytical approximation for the solution of the Fokker-Planck equation with a time and velocity dependent diffusion coefficients is proposed.

  15. Will peak oil accelerate carbon dioxide emissions?

    NASA Astrophysics Data System (ADS)

    Caldeira, K.; Davis, S. J.; Cao, L.

    2008-12-01

    The relative scarcity of oil suggests that oil production is peaking and will decline thereafter. Some have suggested that this represents an opportunity to reduce carbon dioxide emissions. However, in the absence of constraints on carbon dioxide emission, "peak oil" may drive a shift towards increased reliance on coal as a primary energy source. Because coal per unit energy, in the absence of carbon capture and disposal, releases more carbon dioxide to the atmosphere than oil, "peak oil" may lead to an acceleration of carbon dioxide emissions. We will never run out of oil. As oil becomes increasingly scarce, prices will rise and therefore consumption will diminish. As prices rise, other primary energy sources will become increasingly competitive with oil. The developed world uses oil primarily as a source of transportation fuels. The developing world uses oil primarily for heat and power, but the trend is towards increasing reliance on oil for transportation. Liquid fuels, including petroleum derivatives such as gasoline and diesel fuel, are attractive as transportation fuels because of their relative abundance of energy per unit mass and volume. Such considerations are especially important for the air transport industry. Today, there is little that can compete with petroleum-derived transportation fuels. Future CO2 emissions from the transportation sector largely depend on what replaces oil as a source of fuel. Some have suggested that biomass-derived ethanol, hydrogen, or electricity could play this role. Each of these potential substitutes has its own drawbacks (e.g., low power density per unit area in the case of biomass, low power density per unit volume in the case of hydrogen, and low power density per unit mass in the case of battery storage). Thus, it is entirely likely that liquefaction of coal could become the primary means by which transportation fuels are produced. Since the burning of coal produces more CO2 per unit energy than does the burning of

  16. Exceptional Ground Accelerations and Velocities Caused by Earthquakes

    SciTech Connect

    Anderson, John

    2008-01-17

    This project aims to understand the characteristics of the free-field strong-motion records that have yielded the 100 largest peak accelerations and the 100 largest peak velocities recorded to date. The peak is defined as the maximum magnitude of the acceleration or velocity vector during the strong shaking. This compilation includes 35 records with peak acceleration greater than gravity, and 41 records with peak velocities greater than 100 cm/s. The results represent an estimated 150,000 instrument-years of strong-motion recordings. The mean horizontal acceleration or velocity, as used for the NGA ground motion models, is typically 0.76 times the magnitude of this vector peak. Accelerations in the top 100 come from earthquakes as small as magnitude 5, while velocities in the top 100 all come from earthquakes with magnitude 6 or larger. Records are dominated by crustal earthquakes with thrust, oblique-thrust, or strike-slip mechanisms. Normal faulting mechanisms in crustal earthquakes constitute under 5% of the records in the databases searched, and an even smaller percentage of the exceptional records. All NEHRP site categories have contributed exceptional records, in proportions similar to the extent that they are represented in the larger database.

  17. Peak accelerations from the 17 October 1989 Loma Prieta earthquake

    USGS Publications Warehouse

    Boore, D.M.; Seekins, L.; Joyner, W.B.

    1989-01-01

    Peak accelerations of the Loma Prieta main shock have been tabulated from instruments maintained by a number of organizations. A subset of 86 records from nominally free-field sites have been analyzed which have been subdivided into rock, alluvium, and bay-mud categories according to data available in various reports. After correction for attenuation, the peak accelerations on rock, alluvium, and bay-mud sites are factors of 1.6, 1.8 and 4.5 larger, on the average, than Joyner and Boore's (1988) predicted values for a M=6.9 earthquake. The Loma Prieta earthquake provided the first opportunity to study the relative amplitudes from strong-motion recordings. -from Authors

  18. Turbulence Hazard Metric Based on Peak Accelerations for Jetliner Passengers

    NASA Technical Reports Server (NTRS)

    Stewart, Eric C.

    2005-01-01

    Calculations are made of the approximate hazard due to peak normal accelerations of an airplane flying through a simulated vertical wind field associated with a convective frontal system. The calculations are based on a hazard metric developed from a systematic application of a generic math model to 1-cosine discrete gusts of various amplitudes and gust lengths. The math model simulates the three degree-of- freedom longitudinal rigid body motion to vertical gusts and includes (1) fuselage flexibility, (2) the lag in the downwash from the wing to the tail, (3) gradual lift effects, (4) a simplified autopilot, and (5) motion of an unrestrained passenger in the rear cabin. Airplane and passenger response contours are calculated for a matrix of gust amplitudes and gust lengths. The airplane response contours are used to develop an approximate hazard metric of peak normal accelerations as a function of gust amplitude and gust length. The hazard metric is then applied to a two-dimensional simulated vertical wind field of a convective frontal system. The variations of the hazard metric with gust length and airplane heading are demonstrated.

  19. Peak Ground Velocities for Seismic Events at Yucca Mountain, Nevada

    SciTech Connect

    K. Coppersmith; R. Quittmeyer

    2005-02-16

    This report describes a scientific analysis to bound credible horizontal peak ground velocities (PGV) for the repository waste emplacement level at Yucca Mountain. Results are presented as a probability distribution for horizontal PGV to represent uncertainties in the analysis. The analysis also combines the bound to horizontal PGV with results of ground motion site-response modeling (BSC 2004 [DIRS 170027]) to develop a composite hazard curve for horizontal PGV at the waste emplacement level. This result provides input to an abstraction of seismic consequences (BSC 2004 [DIRS 169183]). The seismic consequence abstraction, in turn, defines the input data and computational algorithms for the seismic scenario class of the total system performance assessment (TSPA). Planning for the analysis is documented in Technical Work Plan TWP-MGR-GS-000001 (BSC 2004 [DIRS 171850]). The bound on horizontal PGV at the repository waste emplacement level developed in this analysis complements ground motions developed on the basis of PSHA results. In the PSHA, ground motion experts characterized the epistemic uncertainty and aleatory variability in their ground motion interpretations. To characterize the aleatory variability they used unbounded lognormal distributions. As a consequence of these characterizations, as seismic hazard calculations are extended to lower and lower annual frequencies of being exceeded, the ground motion level increases without bound, eventually reaching levels that are not credible (Corradini 2003 [DIRS 171191]). To provide credible seismic inputs for TSPA, in accordance with 10 Code of Federal Regulations (CFR) 63.102(j) [DIRS 156605], this complementary analysis is carried out to determine reasonable bounding values of horizontal PGV at the waste emplacement level for annual frequencies of exceedance as low as 10{sup -8}. For each realization of the TSPA seismic scenario, the results of this analysis provide a constraint on the values sampled from the

  20. Grounding and shielding in the accelerator environment

    SciTech Connect

    Kerns, Q.

    1991-01-01

    Everyday features of the accelerator environment include long cable runs, high power and low level equipment sharing building space, stray electromagnetic fields and ground voltage differences between the sending and receiving ends of an installation. This paper pictures some Fermilab installations chosen to highlight significant features and presents practices, test methods and equipment that have been helpful in achieving successful shielding. Throughout the report are numbered statements aimed at summarizing good practices and avoiding pitfalls.

  1. Grounding and shielding in the accelerator environment

    SciTech Connect

    Kerns, Q.

    1991-12-31

    Everyday features of the accelerator environment include long cable runs, high power and low level equipment sharing building space, stray electromagnetic fields and ground voltage differences between the sending and receiving ends of an installation. This paper pictures some Fermilab installations chosen to highlight significant features and presents practices, test methods and equipment that have been helpful in achieving successful shielding. Throughout the report are numbered statements aimed at summarizing good practices and avoiding pitfalls.

  2. Commissioning of the Ground Test Accelerator RFQ

    SciTech Connect

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Connolly, R.; Garnett, R.; Gilpatrick, J.D.; Guy, F.W.; Ingalls, W.B.; Little, C.; Lohson, R.A.; Lloyd, S.; Neuschaefer, G.; Power, J.; Saadatmand, K.; Sandoval, D.P.; Stevens, R.R.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1992-09-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H{sup {minus}} beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on-line. The commissioning stages are the 35 key H{sup {minus}} injector, the 2.5 MeV Radio Frequency Quadrupole (RFQ), the Intertank Matching Section (IMS), the 3.2 MeV first 2{beta}{gamma} Drift Tube Linac (DTL-1) module, the 8.7 MeV 2{beta}{gamma} DTL (modules 1--5), and the 24 MeV GTA; all 10 DTL modules. Commissioning results from the RFQ beam experiments will be presented along with comparisons to simulations.

  3. Commissioning of the Ground Test Accelerator RFQ

    SciTech Connect

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Connolly, R.; Garnett, R.; Gilpatrick, J.D.; Guy, F.W.; Ingalls, W.B.; Little, C.; Lohson, R.A.; Lloyd, S.; Neuschaefer, G.; Power, J.; Saadatmand, K.; Sandoval, D.P.; Stevens, R.R.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1992-01-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H{sup {minus}} beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on-line. The commissioning stages are the 35 key H{sup {minus}} injector, the 2.5 MeV Radio Frequency Quadrupole (RFQ), the Intertank Matching Section (IMS), the 3.2 MeV first 2{beta}{gamma} Drift Tube Linac (DTL-1) module, the 8.7 MeV 2{beta}{gamma} DTL (modules 1--5), and the 24 MeV GTA; all 10 DTL modules. Commissioning results from the RFQ beam experiments will be presented along with comparisons to simulations.

  4. Strong ground motion data from the 1983 Borah Peak, Idaho earthquake recorded at the Idaho National Engineering Laboratory

    SciTech Connect

    Jackson, S.M.; Boatwright, J.

    1985-01-01

    The 1983 Borah Peak, Idaho Earthquake was the largest normal faulting event to occur in the last 20 years. There were no near-field recordings of ground motion during the main shock, however, thirteen accelerographs in a permanent array at the Idaho National Engineering Laboratory (INEL) recorded the event at epicentral distances of 90 to 110 km. Peak horizontal accelerations (PGA) recorded at accelerographs above ground-floor level range from 0.037 to 0.187 g. Accelerographs at basement and free-field sites recorded as low as 0.022 g and as high as 0.078 g. Peak vertical accelerations range from 0.016 g at ground level to 0.059 g above ground floor level. A temporary array of digital seismographs deployed by the US Geological Survey (USGS) in the epicentral area recorded ground motion from six large aftershocks at epicentral distances of 4 to 45 km; the largest of these aftershocks also triggered four accelerographs in the INEL array. Two separate analyses were used to estimate near-field ground motion. The first analysis uses the attenuation of the aftershock PGA measurements to extrapolate the INEL main shock PGA measurements into the near-field. This estimates an upper limit of 0.8 g for near-field ground motion. In the second analysis, a set of main shock accelerograms were synthesized. Wave propagation effects were determined from aftershock recordings at one of the USGS portable stations and an INEL seismograph station. These effects were removed from one of the INEL main shock acceleration traces. The synthetic accelerograms were derived for a hypothetical station southwest of Mackay, Idaho. The PGA measured from the synthetic accelerograms were 0.08, 0.14, 0.15, 0.23 g. These estimates correlate well with ground motion expected for an area of Intensity VII.

  5. Equations for estimating horizontal response spectra and peak acceleration from western North American earthquakes: A summary of recent work

    USGS Publications Warehouse

    Boore, D.M.; Joyner, W.B.; Fumal, T.E.

    1997-01-01

    In this paper we summarize our recently-published work on estimating horizontal response spectra and peak acceleration for shallow earthquakes in western North America. Although none of the sets of coefficients given here for the equations are new, for the convenience of the reader and in keeping with the style of this special issue, we provide tables for estimating random horizontal-component peak acceleration and 5 percent damped pseudo-acceleration response spectra in terms of the natural, rather than common, logarithm of the ground-motion parameter. The equations give ground motion in terms of moment magnitude, distance, and site conditions for strike-slip, reverse-slip, or unspecified faulting mechanisms. Site conditions are represented by the shear velocity averaged over the upper 30 m, and recommended values of average shear velocity are given for typical rock and soil sites and for site categories used in the National Earthquake Hazards Reduction Program's recommended seismic code provisions. In addition, we stipulate more restrictive ranges of magnitude and distance for the use of our equations than in our previous publications. Finally, we provide tables of input parameters that include a few corrections to site classifications and earthquake magnitude (the corrections made a small enough difference in the ground-motion predictions that we chose not to change the coefficients of the prediction equations).

  6. Ground motions and its effects in accelerator design

    SciTech Connect

    Fischer, G.E.

    1984-07-01

    This lecture includes a discussion of types of motion, frequencies of interest, measurements at SLAC, some general comments regarding local sources of ground motion at SLAC, and steps that can be taken to minimize the effects of ground motion on accelerators. (GHT)

  7. Ground motion: An introduction for accelerator builders

    SciTech Connect

    Fischer, G.E.

    1992-02-01

    In this seminar we will review some of the characteristics of the major classes of ground motion in order to determine whether their effects must be considered or place fundamental limits on the sitting and/or design of modern storage rings and linear colliders. The classes discussed range in frequency content from tidal deformation and tectonic motions through earthquakes and microseisms. Countermeasures currently available are briefly discussed.

  8. Evaluation of Ground-Motion Modeling Techniques for Use in Global ShakeMap - A Critique of Instrumental Ground-Motion Prediction Equations, Peak Ground Motion to Macroseismic Intensity Conversions, and Macroseismic Intensity Predictions in Different Tectonic Settings

    USGS Publications Warehouse

    Allen, Trevor I.; Wald, David J.

    2009-01-01

    Regional differences in ground-motion attenuation have long been thought to add uncertainty in the prediction of ground motion. However, a growing body of evidence suggests that regional differences in ground-motion attenuation may not be as significant as previously thought and that the key differences between regions may be a consequence of limitations in ground-motion datasets over incomplete magnitude and distance ranges. Undoubtedly, regional differences in attenuation can exist owing to differences in crustal structure and tectonic setting, and these can contribute to differences in ground-motion attenuation at larger source-receiver distances. Herein, we examine the use of a variety of techniques for the prediction of several ground-motion metrics (peak ground acceleration and velocity, response spectral ordinates, and macroseismic intensity) and compare them against a global dataset of instrumental ground-motion recordings and intensity assignments. The primary goal of this study is to determine whether existing ground-motion prediction techniques are applicable for use in the U.S. Geological Survey's Global ShakeMap and Prompt Assessment of Global Earthquakes for Response (PAGER). We seek the most appropriate ground-motion predictive technique, or techniques, for each of the tectonic regimes considered: shallow active crust, subduction zone, and stable continental region.

  9. Preliminary description of the ground test accelerator cryogenic cooling system

    SciTech Connect

    Edeskuty, F.J.; Stewart, W.F.

    1988-01-01

    The Ground Test Accelerator (GTA) under construction at the Los Alamos National Laboratory is part of the Neutral Particle Beam Program supported by the Strategic Defense Initiative Office. The GTA is a full-sized test facility to evaluate the feasibility of using a negative ion accelerator to produce a neutral particle beam (NPB). The NPB would ultimately be used outside the earth's atmosphere as a target discriminator or as a directed energy weapon. The operation of the GTA at cryogenic temperature is advantageous for two reasons: first, the decrease of temperature caused a corresponding decrease in the rf heating of the copper in the various units of the accelerator, and second, at the lower temperature the decrease in the thermal expansion coefficient also provides greater thermal stability and consequently, better operating stability for the accelerator. This paper discusses the cryogenic cooling system needed to achieve these advantages. 5 figs., 3 tabs.

  10. Peak acceleration during impact with helmet materials: effects of impactor mass and speed.

    PubMed

    Hutchinson, Timothy Paul

    2014-01-01

    The impact properties of six foam materials used for energy absorption as the liner of children's helmets, reported by Gimbel and Hoshizaki are considered further. In high-energy impacts, almost complete compression of the energy-absorbing material (bottoming out) may occur, and the severity of the impact increases greatly. Too soft a material means bottoming out occurs at low speeds, but if it is too stiff, the material itself is injurious. The fitting of equations to results in 'no bottoming out' and 'bottoming out' conditions may help assessment of what compromise is appropriate. The equations in this article correspond to peak acceleration being proportional to power functions of impactor speed and mass. 1. When there was no bottoming out, peak acceleration was found to be proportional to m (∧)(c-1).v (∧)(2c), with c being approximately 0.25. 2. For bottoming out, peak acceleration was found to be proportional to m (∧)(p).v (∧)(q), with p and q being approximately 2 and approximately 3. 3. The constants of proportionality were related to material density in a regular way. PMID:24444232

  11. Maps Showing Ground-Water Conditions in the San Francisco Peaks Area, Coconino County, Arizona - 1979

    USGS Publications Warehouse

    Appel, Cynthia L.; Bills, Donald J.

    1981-01-01

    INTRODUCTION The San Francisco Peaks area includes about 2,300 mi2, of which about 500 mi2 is in the Navajo Indian Reservation, in north-central Arizona. Ground-water development has been slight except for the public-supply wells for Flagstaff and domestic wells in Fort Valley, Pitman Valley, and the area west of Elden Mountain. The public water supply for Flagstaff is primarily from Upper Lake Mary but is supplemented by ground water from wells near Woody Mountain and Lower Lake Mary and from wells and springs in the Inner Basin. In 1978 about 2,000 acre-ft of ground water was withdrawn for public, industrial, domestic, and stock supplies in the San Francisco Peaks area. The hydrologic data on which these maps are based are available, for the most part, in computer-printout form and may be consulted at the Arizona Department of Water Resources, 99 East Virginia, Phoenix, and at U.S. Geological Survey offices in: Federal Building, 301 West Congress Street, Tucson; Valley Center, Suite 1880, Phoenix; and 2255 North Gemini Drive, Building 3, Flagstaff. Material from which copies can be made at private expense is available at the Tucson, Phoenix, and Flagstaff offices of the U.S. Geological Survey. Only the springs for which discharge data are available are shown on the maps, and only selected wells are shown in areas of high well density.

  12. Different Modes of Feedback and Peak Vertical Ground Reaction Force During Jump Landing: A Systematic Review

    PubMed Central

    Ericksen, Hayley M.; Gribble, Phillip A.; Pfile, Kate R.; Pietrosimone, Brian G.

    2013-01-01

    Context: Excessive ground reaction force when landing from a jump may result in lower extremity injuries. It is important to better understand how feedback can influence ground reaction force (GRF) and potentially reduce injury risk. Objective: To determine the effect of expert-provided (EP), self-analysis (SA), and combination EP and SA (combo) feedback on reducing peak vertical GRF during a jump-landing task. Data Sources: We searched the Web of Science database on July 1, 2011; using the search terms ground reaction force, landing biomechanics, and feedback elicited 731 initial hits. Study Selection: Of the 731 initial hits, our final analysis included 7 studies that incorporated 32 separate data comparisons. Data Extraction: Standardized effect sizes and 95% confidence intervals (CIs) were calculated between pretest and posttest scores for each feedback condition. Data Synthesis: We found a homogeneous beneficial effect for combo feedback, indicating a reduction in GRF with no CIs crossing zero. We also found a homogeneous beneficial effect for EP feedback, but the CIs from 4 of the 10 data comparisons crossed zero. The SA feedback showed strong, definitive effects when the intervention included a videotape SA, with no CIs crossing zero. Conclusions: Of the 7 studies reviewed, combo feedback seemed to produce the greatest decrease in peak vertical GRF during a jump-landing task. PMID:24067153

  13. Attenuation characteristics of peak horizontal acceleration in northeast and southwest China

    SciTech Connect

    Peng, K.Z.; Song, L.; Wu, F.T.

    1985-05-01

    Regional seismic characteristics in northeastern and southwestern China are quite different. Earthquakes are more frequent in SW China than in NE China and intensity attenuates faster in SW China than in NE China Through regression analyses of data from these two regions we have found the attenuation of peak horizontal accelerations also to be noticeably different. For northeastern China the regression is log/sub 10/(a) = - 0.474+0.613M - 0.873 log/sub 10/(R) - 0.00206R and for southwestern China, the regression is log/sub 10/(a) = 0.437+0.454M - 0.739 log/sub 10/(R) - 0.00279R where a is acceleration in cm/sec/sup 2/, M is the Chinese surface wave magnitude (Institute of Geophysics, State Seismological Bureau), and distance in kilometres. The formula for northeastern China has distance coefficients similar to those for Central United States as derived by Nuttli and Herrmann.

  14. Earthquake magnitude calculation without saturation from the scaling of peak ground displacement

    NASA Astrophysics Data System (ADS)

    Melgar, Diego; Crowell, Brendan W.; Geng, Jianghui; Allen, Richard M.; Bock, Yehuda; Riquelme, Sebastian; Hill, Emma M.; Protti, Marino; Ganas, Athanassios

    2015-07-01

    GPS instruments are noninertial and directly measure displacements with respect to a global reference frame, while inertial sensors are affected by systematic offsets—primarily tilting—that adversely impact integration to displacement. We study the magnitude scaling properties of peak ground displacement (PGD) from high-rate GPS networks at near-source to regional distances (~10-1000 km), from earthquakes between Mw6 and 9. We conclude that real-time GPS seismic waveforms can be used to rapidly determine magnitude, typically within the first minute of rupture initiation and in many cases before the rupture is complete. While slower than earthquake early warning methods that rely on the first few seconds of P wave arrival, our approach does not suffer from the saturation effects experienced with seismic sensors at large magnitudes. Rapid magnitude estimation is useful for generating rapid earthquake source models, tsunami prediction, and ground motion studies that require accurate information on long-period displacements.

  15. Cryogenic cooling system for the ground test accelerator

    SciTech Connect

    Edeskuty, F.J.; Stewart, W.F.; Moeller, J.; Durham, F.; Spulgis, I.

    1993-06-01

    A cryogenic cooling system has been designed, built and tested for the Ground Test Accelerator (GTA) at the Los Alamos National Laboratory. Major components of the GTA require cooling to less than 50 K to reduce rf-heating and to increase thermal stability. The cooling system is capable of cooling (at an acceptable rate for thermal stresses) the cryogenically cooled components and then maintaining them at their operating temperature during accelerator testing for all modes and power levels of operation. The accelerator components are cooled by circulating cold, dense helium gas (about 21 K and 2.1 MPa) through the components. The circulating helium is refrigerated in a heat exchanger that uses boiling liquid hydrogen as a source of refrigeration. The cryogenic cooling system consists of the following major components: a liquid hydrogen (LH{sub 2}) storage Dewar with a transfer line to an LH{sub 2} run tank containing an LH{sub 2}/gaseous helium (GHe) heat exchanger, circulation lines, and a circulation pump. The system, sized to cool a load of approximately 40 kW at temperatures as low as 20 K, is operational, but has not yet been operated in conjunction with the accelerator.

  16. Cryogenic cooling system for the ground test accelerator

    SciTech Connect

    Edeskuty, F.J.; Stewart, W.F.; Moeller, J.; Durham, F. ); Spulgis, I. )

    1993-01-01

    A cryogenic cooling system has been designed, built and tested for the Ground Test Accelerator (GTA) at the Los Alamos National Laboratory. Major components of the GTA require cooling to less than 50 K to reduce rf-heating and to increase thermal stability. The cooling system is capable of cooling (at an acceptable rate for thermal stresses) the cryogenically cooled components and then maintaining them at their operating temperature during accelerator testing for all modes and power levels of operation. The accelerator components are cooled by circulating cold, dense helium gas (about 21 K and 2.1 MPa) through the components. The circulating helium is refrigerated in a heat exchanger that uses boiling liquid hydrogen as a source of refrigeration. The cryogenic cooling system consists of the following major components: a liquid hydrogen (LH[sub 2]) storage Dewar with a transfer line to an LH[sub 2] run tank containing an LH[sub 2]/gaseous helium (GHe) heat exchanger, circulation lines, and a circulation pump. The system, sized to cool a load of approximately 40 kW at temperatures as low as 20 K, is operational, but has not yet been operated in conjunction with the accelerator.

  17. Cryogenic cooling system for the Ground Test Accelerator

    SciTech Connect

    Edeskuty, F.J.; Stewart, W.F.; Moeller, J.; Durham, F.; Spulgis, I.

    1994-12-31

    A cryogenic cooling system has been designed, built and tested for the Ground Test Accelerator (GTA) at the Los Alamos National Laboratory. Major components of the GTA require cooling to less than 50 K to reduce rf-heating and to increase thermal stability. The cooling system is capable of cooling (at an acceptable rate for thermal stresses) the cryogenically cooled components and then maintaining them at their operating temperature during accelerator testing for all modes and power levels of operation. The accelerator components are cooled by circulating cold, dense helium gas (about 21 K and 2.1 MPa) through the components. The circulating helium is refrigerated in a heat exchanger that uses boiling liquid hydrogen as a source of refrigeration. The cryogenic cooling system consists of the following major components: a liquid hydrogen (LH{sub 2}) storage Dewar with a transfer line to an LH{sub 2} run tank containing an LH{sub 2}/gaseous helium (GHe) heat exchanger, circulation lines, and a circulation pump. The system, sized to cool a load of approximately 40 kW at temperatures as low as 20 K, is operational, but has not yet been operated in conjunction with the accelerator.

  18. Commissioning of the Ground Test Accelerator Intertank Matching Section

    SciTech Connect

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Cole, R.; Connolly, R.; Gilpatrick, J.D.; Ingalls, W.B.; Kersteins, D.; Little, C.; Lohsen, R.A.; Lysenko, W.P.; Mottershead, C.T.; Power, J.; Rusthoi, D.P.; Sandoval, D.P.; Stevens, R.R.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1992-09-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H{sup {minus}} beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on-line. The commissioning stages are the 35 keV H{sup {minus}} injector, the 2.5 MeV Radio Frequency Quadrupole (RFQ), the Intertank Matching Section (IMS), the 3.2 MeV first 2{beta}{gamma} Drift Tube Linac (DTL-1) module, the 8.7 MeV 2{beta}{gamma} DTL (modules 1--5), and the 24 MeV GTA; all 10 DTL modules. Commissioning results from the IMS beam experiments will be presented.

  19. Beam loading and cavity compensation for the ground test accelerator

    SciTech Connect

    Jachim, S.P.; Natter, E.F.

    1989-01-01

    The Ground Test Accelerator (GTA) will be a heavily beam-loaded H/sup minus/ linac with tight tolerances on accelerating field parameters. The methods used in modeling the effects of beam loading in this machine are described. The response of the cavity to both beam and radio-frequency (RF) drive stimulus is derived, including the effects of cavity detuning. This derivation is not restricted to a small-signal approximation. An analytical method for synthesizing a predistortion network that decouples the amplitude and phase responses of the cavity is also outlined. Simulation of performance, including beam loading, is achieved through use of a control system analysis software package. A straightforward method is presented for extrapolating this work to model large coupled structures with closely spaced parasitic modes. Results to date have enabled the RF control system designs for GTA to be optimized and have given insight into their operation. 6 refs., 10 figs.

  20. Commissioning of the Ground Test Accelerator Intertank Matching Section

    SciTech Connect

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Cole, R.; Connolly, R.; Gilpatrick, J.D.; Ingalls, W.B.; Kersteins, D.; Little, C.; Lohsen, R.A.; Lysenko, W.P.; Mottershead, C.T.; Power, J.; Rusthoi, D.P.; Sandoval, D.P.; Stevens, R.R.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1992-01-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H{sup {minus}} beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on-line. The commissioning stages are the 35 keV H{sup {minus}} injector, the 2.5 MeV Radio Frequency Quadrupole (RFQ), the Intertank Matching Section (IMS), the 3.2 MeV first 2{beta}{gamma} Drift Tube Linac (DTL-1) module, the 8.7 MeV 2{beta}{gamma} DTL (modules 1--5), and the 24 MeV GTA; all 10 DTL modules. Commissioning results from the IMS beam experiments will be presented.

  1. GTA (ground test accelerator) Phase 1: Baseline design report

    SciTech Connect

    Not Available

    1986-08-01

    The national Neutral Particle Beam (NPB) program has two objectives: to provide the necessary basis for a discriminator/weapon decision by 1992, and to develop the technology in stages that lead ultimately to a neutral particle beam weapon. The ground test accelerator (GTA) is the test bed that permits the advancement of the state-of-the-art under experimental conditions in an integrated automated system mode. An intermediate goal of the GTA program is to support the Integrated Space Experiments, while the ultimate goal is to support the 1992 decision. The GTA system and each of its major subsystems are described, and project schedules and resource requirements are provided. (LEW)

  2. Near-fault peak ground velocity from earthquake and laboratory data

    USGS Publications Warehouse

    McGarr, A.; Fletcher, Joe B.

    2007-01-01

    We test the hypothesis that peak ground velocity (PGV) has an upper bound independent of earthquake magnitude and that this bound is controlled primarily by the strength of the seismogenic crust. The highest PGVs, ranging up to several meters per second, have been measured at sites within a few kilometers of the causative faults. Because the database for near-fault PGV is small, we use earthquake slip models, laboratory experiments, and evidence from a mining-induced earthquake to investigate the factors influencing near-fault PGV and the nature of its scaling. For each earthquake slip model we have calculated the peak slip rates for all subfaults and then chosen the maximum of these rates as an estimate of twice the largest near-fault PGV. Nine slip models for eight earthquakes, with magnitudes ranging from 6.5 to 7.6, yielded maximum peak slip rates ranging from 2.3 to 12 m/sec with a median of 5.9 m/sec. By making several adjustments, PGVs for small earthquakes can be simulated from peak slip rates measured during laboratory stick-slip experiments. First, we adjust the PGV for differences in the state of stress (i.e., the difference between the laboratory loading stresses and those appropriate for faults at seismogenic depths). To do this, we multiply both the slip and the peak slip rate by the ratio of the effective normal stresses acting on fault planes measured at 6.8 km depth at the KTB site, Germany (deepest available in situ stress measurements), to those acting on the laboratory faults. We also adjust the seismic moment by replacing the laboratory fault with a buried circular shear crack whose radius is chosen to match the experimental unloading stiffness. An additional, less important adjustment is needed for experiments run in triaxial loading conditions. With these adjustments, peak slip rates for 10 stick-slip events, with scaled moment magnitudes from -2.9 to 1.0, range from 3.3 to 10.3 m/sec, with a median of 5.4 m/sec. Both the earthquake and

  3. Ground motion prediction equations for horizontal and vertical components of acceleration in Northern Iran

    NASA Astrophysics Data System (ADS)

    Soghrat, M. R.; Ziyaeifar, M.

    2016-05-01

    Recent studies have shown that the vertical component of ground motion can be quite destructive on a variety of structural systems. Development of response spectrum for design of buildings subjected to vertical component of earthquake needs ground motion prediction equations (GMPEs). The existing GMPEs for northern Iranian plateau are proposed for the horizontal component of earthquake, and there is not any specified GMPE for the vertical component of earthquake in this region. Determination of GMPEs is mostly based on regression analyses on earthquake parameters such as magnitude, site class, distance, and spectral amplitudes. In this study, 325 three-component records of 55 earthquakes with magnitude ranging from M w 4.1 to M w 7.3 are used for estimation on the regression coefficients. Records with distances less than 300 km are selected for analyses in the database. The regression analyses on earthquake parameters results in determination of GMPEs for peak ground acceleration and spectral acceleration for both horizontal and vertical components of the ground motion. The correlation between the models for vertical and horizontal GMPEs is studied in details. These models are later compared with some other available GMPEs. According to the result of this investigation, the proposed GMPEs are in agreement with the other relationships that were developed based on the local and regional data.

  4. On Higher Ground: How Well Can Dynamic Body Acceleration Determine Speed in Variable Terrain?

    PubMed Central

    Bidder, Owen R.; Qasem, Lama A.; Wilson, Rory P.

    2012-01-01

    Introduction Animal travel speed is an ecologically significant parameter, with implications for the study of energetics and animal behaviour. It is also necessary for the calculation of animal paths by dead-reckoning. Dead-reckoning uses heading and speed to calculate an animal’s path through its environment on a fine scale. It is often used in aquatic environments, where transmission telemetry is difficult. However, its adoption for tracking terrestrial animals is limited by our ability to measure speed accurately on a fine scale. Recently, tri-axial accelerometers have shown promise for estimating speed, but their accuracy appears affected by changes in substrate and surface gradients. The purpose of the present study was to evaluate four metrics of acceleration; Overall dynamic body acceleration (ODBA), vectorial dynamic body acceleration (VDBA), acceleration peak frequency and acceleration peak amplitude, as proxies for speed over hard, soft and inclined surfaces, using humans as a model species. Results A general linear model (GLM) showed a significant difference in the relationships between the metrics and speed depending on substrate or surface gradient. When the data from all surface types were considered together, VeDBA had the highest coefficient of determination. Conclusions All of the metrics showed some variation in their relationship with speed according to the surface type. This indicates that changes in the substrate or surface gradient during locomotion by animals would produce errors in speed estimates, and also in dead-reckoned tracks if they were calculated from speeds based entirely on a priori calibrations. However, we describe a method by which the relationship between acceleration metrics and speed can be corrected ad hoc, until tracks accord with periodic ground truthed positions, obtained via a secondary means (e.g. VHF or GPS telemetry). In this way, dead-reckoning provides a means to obtain fine scale movement data for terrestrial

  5. Lessons learned on the Ground Test Accelerator control system

    SciTech Connect

    Kozubal, A.J.; Weiss, R.E.

    1994-09-01

    When we initiated the control system design for the Ground Test Accelerator (GTA), we envisioned a system that would be flexible enough to handle the changing requirements of an experimental project. This control system would use a developers` toolkit to reduce the cost and time to develop applications for GTA, and through the use of open standards, the system would accommodate unforeseen requirements as they arose. Furthermore, we would attempt to demonstrate on GTA a level of automation far beyond that achieved by existing accelerator control systems. How well did we achieve these goals? What were the stumbling blocks to deploying the control system, and what assumptions did we make about requirements that turned out to be incorrect? In this paper we look at the process of developing a control system that evolved into what is now the ``Experimental Physics and Industrial Control System`` (EPICS). Also, we assess the impact of this system on the GTA project, as well as the impact of GTA on EPICS. The lessons learned on GTA will be valuable for future projects.

  6. Ground Penetrating Radar Imaging of the Emigrant Peak Fault Zone and Alluvial Fan

    NASA Astrophysics Data System (ADS)

    Christie, M. W.; Tsoflias, G. P.

    2006-12-01

    Near-surface geophysical studies at the University of Kansas are investigating active faulting in the Eastern California Shear Zone. The Emigrant Peak Fault, in Fish Lake Valley, Nevada, is a normal fault that aids in the transfer of right-lateral deformation associated with the Furnace Creek/Fish Lake/Death Valley fault system of the Walker Lane Belt/Eastern California Shear Zone. During the spring and summer of 2006 we collected ground penetrating radar (GPR) across the deformed alluvial fan associated with the Emigrant Peak Fault. The GPR study is conducted in conjunction with high resolution shallow seismic and geologic investigations underway to more fully characterize the fault zone. The GPR data crosses the surface expression of the Emigrant Peak Fault and it is comprised of a 50 MHz 3-D grid and 25 MHz 2-D lines. The 3-D grid covers an area of 115m X 500m at 1m trace spacing, 5m in-line spacing and intersecting cross-lines at 50, 100, 150, 250, and 450m across the in-lines. 2-D GPR lines were acquired at coincident locations with the shallow seismic data and along a 1500m regional line over the fault and alluvial fan deposits. Depth of imaging ranged between 17m for the 50 MHz data and 25m for the 25 MHz data. GPR imaging aids in the characterization of the fault zone structurally as well as characterizing alluvial fan stratigraphy. Data shows stratigraphic reflectors on a 1m scale. Reflector geometries are quite complex, showing continuous coherent events, as well as areas that are less coherent which appear to signal a change to more boulder/cobble-rich deposition, a common characteristic in debris-flow dominated alluvial fans. The reflectors are also heavily influenced by the structural components that are imaged. The GPR shows a number of west-dipping faults that seem to migrate towards the basin. The faults are not imaged merely as interrupted reflectors, but the fault surfaces are actually imaged. Stratigraphic reflectors truncate at the faults in

  7. Why do oceanic negative cloud-to-ground lightning exhibit larger peak current values?

    NASA Astrophysics Data System (ADS)

    Chronis, T.; Koshak, W.; McCaul, E.

    2016-04-01

    This study examines the temporal (monthly) and spatial climatology (2004-2010) of the first return stroke of the cloud-to-ground (CG) lightning flash peak current (Ip) across various land/water boundaries over the contiguous United States. Four regions are examined: the Gulf of Mexico (region 1), the Florida peninsula (region 2), Lake Michigan (region 3), and part of the U.S. Mid-Atlantic (region 4). The crosss across the coastlines of regions 1, 2, and 4 show a gradual oceanward increase in the mean negative polarity CG peak current values (-Ip). This transition along the respective land/ocean boundaries is not sharp but gradual. In direct contrast with ocean, there is no consistent behavior in -Ip values as we move from land out across the fresh water of Lake Michigan (region 3). Meanwhile, the positive CG flash peak current (+Ip) values do not exhibit a consistent variation across any coastal boundary. For region 1, the -Ip values increase as we move toward the coast (southwards) especially during the wet season (June-October). This finding is in direct contrast with studies that documented winter as the season of maximum -Ip values. The zonal and seasonal variations of -Ip values across region 4 are not quite as pronounced, but the oceanic -Ip values are still larger than over the adjoining landmass. We explore in turn which up to date hypotheses pertinent to the oceanic -Ip enhancement are supported or refuted by our findings. It is concluded that the oceanic -Ip enhancement is not an artifact related to CG detection or Ip retrieval methods, nor is it likely related to the cloud top heights or CG activity. The study cannot refute the role of electrical conductivity and its contribution to CG leader attachment processes. However, given the observed "blurred transition" of the Ip values across the coastlines this paper suggests that likely the main physical mechanism is acting on the thundercloud potential. The recently suggested role of sodium chloride (Na

  8. Procedure to estimate maximum ground acceleration from macroseismic intensity rating: application to the Lima, Perú data from the October-3-1974-8.1-Mw earthquake

    NASA Astrophysics Data System (ADS)

    Ocola, L.

    2008-01-01

    Post-disaster reconstruction management of urban areas requires timely information on the ground response microzonation to strong levels of ground shaking to minimize the rebuilt-environment vulnerability to future earthquakes. In this paper, a procedure is proposed to quantitatively estimate the severity of ground response in terms of peak ground acceleration, that is computed from macroseismic rating data, soil properties (acoustic impedance) and predominant frequency of shear waves at a site. The basic mathematical relationships are derived from properties of wave propagation in a homogeneous and isotropic media. We define a Macroseismic Intensity Scale IMS as the logarithm of the quantity of seismic energy that flows through a unit area normal to the direction of wave propagation in unit time. The derived constants that relate the IMS scale and peak acceleration agree well with coefficients derived from a linear regression between MSK macroseismic rating and peak ground acceleration for historical earthquakes recorded at a strong motion station, at IGP's former headquarters, since 1954. The procedure was applied to 3-October-1974 Lima macroseismic intensity data at places where there was geotechnical data and predominant ground frequency information. The observed and computed peak acceleration values, at nearby sites, agree well.

  9. Peak Vertical Ground Reaction Force during Two-Leg Landing: A Systematic Review and Mathematical Modeling

    PubMed Central

    Feng, Tienan; Zhang, Ming

    2014-01-01

    Objectives. (1) To systematically review peak vertical ground reaction force (PvGRF) during two-leg drop landing from specific drop height (DH), (2) to construct a mathematical model describing correlations between PvGRF and DH, and (3) to analyze the effects of some factors on the pooled PvGRF regardless of DH. Methods. A computerized bibliographical search was conducted to extract PvGRF data on a single foot when participants landed with both feet from various DHs. An innovative mathematical model was constructed to analyze effects of gender, landing type, shoes, ankle stabilizers, surface stiffness and sample frequency on PvGRF based on the pooled data. Results. Pooled PvGRF and DH data of 26 articles showed that the square root function fits their relationship well. An experimental validation was also done on the regression equation for the medicum frequency. The PvGRF was not significantly affected by surface stiffness, but was significantly higher in men than women, the platform than suspended landing, the barefoot than shod condition, and ankle stabilizer than control condition, and higher than lower frequencies. Conclusions. The PvGRF and root DH showed a linear relationship. The mathematical modeling method with systematic review is helpful to analyze the influence factors during landing movement without considering DH. PMID:25243113

  10. A simple approach to estimate earthquake magnitude from the arrival time of the peak acceleration amplitude

    NASA Astrophysics Data System (ADS)

    Noda, S.; Yamamoto, S.

    2014-12-01

    In order for Earthquake Early Warning (EEW) to be effective, the rapid determination of magnitude (M) is important. At present, there are no methods which can accurately determine M even for extremely large events (ELE) for EEW, although a number of the methods have been suggested. In order to solve the problem, we use a simple approach derived from the fact that the time difference (Top) from the onset of the body wave to the arrival time of the peak acceleration amplitude of the body wave scales with M. To test this approach, we use 15,172 accelerograms of regional earthquakes (most of them are M4-7 events) from the K-NET, as the first step. Top is defined by analyzing the S-wave in this step. The S-onsets are calculated by adding the theoretical S-P times to the P-onsets which are manually picked. As the result, it is confirmed that logTop has high correlation with Mw, especially for the higher frequency band (> 2Hz). The RMS of residuals between Mw and M estimated in this step is less than 0.5. In case of the 2011 Tohoku earthquake, M is estimated to be 9.01 at 150 seconds after the initiation of the event.To increase the number of the ELE data, we add the teleseismic high frequency P-wave records to the analysis, as the second step. According to the result of various back-projection analyses, we consider the teleseismic P-waves to contain information on the entire rupture process. The BHZ channel data of the Global Seismographic Network for 24 events are used in this step. 2-4Hz data from the stations in the epicentral distance range of 30-85 degrees are used following the method of Hara [2007]. All P-onsets are manually picked. Top obtained from the teleseimic data show good correlation with Mw, complementing the one obtained from the regional data. We conclude that the proposed approach is quite useful for estimating reliable M for EEW, even for the ELE.

  11. Effect of surface conductivity on the peak magnetic field radiated by first return strokes in cloud-to-ground lightning

    NASA Technical Reports Server (NTRS)

    Tyahla, Lori J.; Lopez, Raul E.

    1994-01-01

    The effect of surface conductivity on the peak magnetic field radiated by the first return stroke in cloud-to-ground lightning was investigated by comparing the peak magnetic fields from return strokes that struck water with those that struck land. The data were obtained from a network of three gated, wideband magnetic direction finders (DFs) at the NASA Kennedy Space Center during the summer of 1985. Two geographical areas that were equidistant from two of the direction finders were compared where the flash distances ranged from approximately 40 to 60 km. An unbiased data set was obtained by correcting site errors, equalizing differences in sensor gain, eliminating directional biases in DF triggering, and keeping differences in signal attenuation over the two surfaces to a minimum. When a statistical analysis was performed on the frequency distributions of the signal amplitudes, there was no statistically significant difference in the peak amplitudes of first return strokes over land (lambda = 8.2 x 10(exp -3) mho/m) and over water (lambda = 4 mho/m). Therefore we infer that the conductivity of the underlying surface does not significantly affect the magnitude of the peak magnetic field, and hence the peak current, in the first return stroke of a cloud-to-ground lightning flash.

  12. Peak horizontal acceleration and velocity from strong-motion records including records from the 1979 imperial valley, California, earthquake

    USGS Publications Warehouse

    Joyner, William B.; Boore, David M.

    1981-01-01

    We have taken advantage of the recent increase in strong-motion data at close distances to derive new attenuation relations for peak horizontal acceleration and velocity. This new analysis uses a magnitude-independent shape, based on geometrical spreading and anelastic attenuation, for the attenuation curve. An innovation in technique is introduced that decouples the determination of the distance dependence of the data from the magnitude dependence.

  13. E-beam accelerator cavity development for the ground-based free electron laser

    NASA Astrophysics Data System (ADS)

    Bultman, N. K.; Spalek, G.

    Los Alamos National Laboratory is designing and developing four prototype accelerator cavities for high power testing on the Modular Component Technology Development (MCTD) test stand at Boeing. These cavities provide the basis for the e-beam accelerator hardware that will be used in the Ground Based Free Electron Laser (GBFEL) to be sited at the White Sands Missile Range (WSMR) in New Mexico.

  14. A STUDY ON APPLICABILITY OF GROUND RESPONSE ACCELERATION METHOD TO DEEP VERTICAL UNDERGROUND STRUCTURES

    NASA Astrophysics Data System (ADS)

    Matsumoto, Mai; Shiba, Yukio; Watanabe, Kazuaki

    This paper discusses the applicability of ground response acceleration method to seismic analysis for deep vertical underground structures. To examine the applicability, an analysis of relationships between response of ground and the shaft was conducted. It was found from the analysis that vertical axial stress of the shaft was not correspond with shear stress of ground. Accordingly, it was concluded that the axial stress was not evaluated correctly by the existing method. Therefore, to extend the applicability of the method, ground responses correlated with the axial stress were analyzed and a new method using these ground responses was proposed.

  15. Systolic Peak Detection in Acceleration Photoplethysmograms Measured from Emergency Responders in Tropical Conditions

    PubMed Central

    Elgendi, Mohamed; Norton, Ian; Brearley, Matt; Abbott, Derek; Schuurmans, Dale

    2013-01-01

    Photoplethysmogram (PPG) monitoring is not only essential for critically ill patients in hospitals or at home, but also for those undergoing exercise testing. However, processing PPG signals measured after exercise is challenging, especially if the environment is hot and humid. In this paper, we propose a novel algorithm that can detect systolic peaks under challenging conditions, as in the case of emergency responders in tropical conditions. Accurate systolic-peak detection is an important first step for the analysis of heart rate variability. Algorithms based on local maxima-minima, first-derivative, and slope sum are evaluated, and a new algorithm is introduced to improve the detection rate. With 40 healthy subjects, the new algorithm demonstrates the highest overall detection accuracy (99.84% sensitivity, 99.89% positive predictivity). Existing algorithms, such as Billauer's, Li's and Zong's, have comparable although lower accuracy. However, the proposed algorithm presents an advantage for real-time applications by avoiding human intervention in threshold determination. For best performance, we show that a combination of two event-related moving averages with an offset threshold has an advantage in detecting systolic peaks, even in heat-stressed PPG signals. PMID:24167546

  16. Wind Acceleration in AGB Stars: Solid Ground and Loose Ends

    NASA Astrophysics Data System (ADS)

    Höfner, S.

    2015-08-01

    The winds of cool luminous AGB stars are commonly assumed to be driven by radiative acceleration of dust grains which form in the extended atmospheres produced by pulsation-induced shock waves. The dust particles gain momentum by absorption or scattering of stellar photons, and they drag along the surrounding gas particles through collisions, triggering an outflow. This scenario, here referred to as Pulsation-Enhanced Dust-DRiven Outflow (PEDDRO), has passed a range of critical observational tests as models have developed from empirical and qualitative to increasingly self-consistent and quantitative. A reliable theory of mass loss is an essential piece in the bigger picture of stellar and galactic chemical evolution, and central for determining the contribution of AGB stars to the dust budget of galaxies. In this review, I discuss the current understanding of wind acceleration and indicate areas where further efforts by theorists and observers are needed.

  17. Correlation between full width at half maximum (FWHM) of XRD peak with residual stress on ground surfaces

    NASA Astrophysics Data System (ADS)

    Vashista, M.; Paul, S.

    2012-11-01

    The full width at half maximum (FWHM) of XRD profiles is used to characterize different material properties and surface integrity features. However, there is no literature available that discusses the nature of the correlation between the FWHM of XRD peaks with induced surface residual stress upon grinding with simultaneous occurrence of plastic deformation, formation of white layer, grain elongation, change in microhardness, etc. AISI 1060 steel samples were ground under different grinding domains, i.e. conventional abusive grinding, conventional grinding, cBN grinding and high speed grinding with moderately deep cut. Induction of tensile and compressive residual stress, microstructural changes, white layer formation, grain refinement, plastic deformation, grain elongation and change in microhardness were observed upon grinding AISI 1060 steel. A correlation was established between the FWHM of XRD peaks and surface residual stress when simultaneous changes in microhardness and microstructure, grain elongation, plastic deformation and formation of white layer take place due to grinding. The correlation between FWHM of XRD peak and residual stress appears to be nonlinear due to simultaneous change in other aspects of surface integrity.

  18. Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase

    PubMed Central

    Martínez-Valencia, María Asunción; Romero-Arenas, Salvador; Elvira, José L.L.; González-Ravé, José María; Navarro-Valdivielso, Fernando; Alcaraz, Pedro E.

    2015-01-01

    Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s−1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s−1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration. PMID:26240657

  19. Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase.

    PubMed

    Martínez-Valencia, María Asunción; Romero-Arenas, Salvador; Elvira, José L L; González-Ravé, José María; Navarro-Valdivielso, Fernando; Alcaraz, Pedro E

    2015-06-27

    Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s-1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s-1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration. PMID:26240657

  20. Subionospheric propagation and peak currents of preliminary breakdown pulses before negative cloud-to-ground lightning discharges

    NASA Astrophysics Data System (ADS)

    Kolmašová, Ivana; Santolík, Ondřej; Farges, Thomas; Cummer, Steven A.; Lán, Radek; Uhlíř, Luděk.

    2016-02-01

    We analyze broadband electromagnetic measurements of pulse sequences occurring prior to first return strokes of negative cloud-to-ground lightning flashes. Signals generated by lightning discharges were recorded close to the thunderstorm by a magnetic field receiver and traveled up to 600 km to three distant electric field receivers. We found that amplitudes of observed preliminary breakdown pulses, as well as amplitudes of the corresponding return strokes, are attenuated approximately by 2 dB/100 km when propagating in the Earth-ionosphere waveguide over mountainous terrain. Propagation simulations show that there is a significant contribution of the sky wave signals in the waveforms observed beyond 500 km from their source. The estimated peak currents of the largest preliminary breakdown pulses reach over 60 kA. Such current pulses propagating through in-cloud lightning leader channels in a strong electric field may be able to initiate terrestrial gamma ray flashes.

  1. Properties of the shear stress peak radiated ahead of rapidly accelerating rupture fronts that mediate frictional slip

    PubMed Central

    Svetlizky, Ilya; Pino Muñoz, Daniel; Radiguet, Mathilde; Kammer, David S.; Molinari, Jean-François; Fineberg, Jay

    2016-01-01

    We study rapidly accelerating rupture fronts at the onset of frictional motion by performing high-temporal-resolution measurements of both the real contact area and the strain fields surrounding the propagating rupture tip. We observe large-amplitude and localized shear stress peaks that precede rupture fronts and propagate at the shear-wave speed. These localized stress waves, which retain a well-defined form, are initiated during the rapid rupture acceleration phase. They transport considerable energy and are capable of nucleating a secondary supershear rupture. The amplitude of these localized waves roughly scales with the dynamic stress drop and does not decrease as long as the rupture front driving it continues to propagate. Only upon rupture arrest does decay initiate, although the stress wave both continues to propagate and retains its characteristic form. These experimental results are qualitatively described by a self-similar model: a simplified analytical solution of a suddenly expanding shear crack. Quantitative agreement with experiment is provided by realistic finite-element simulations that demonstrate that the radiated stress waves are strongly focused in the direction of the rupture front propagation and describe both their amplitude growth and spatial scaling. Our results demonstrate the extensive applicability of brittle fracture theory to fundamental understanding of friction. Implications for earthquake dynamics are discussed. PMID:26729877

  2. Properties of the shear stress peak radiated ahead of rapidly accelerating rupture fronts that mediate frictional slip.

    PubMed

    Svetlizky, Ilya; Pino Muñoz, Daniel; Radiguet, Mathilde; Kammer, David S; Molinari, Jean-François; Fineberg, Jay

    2016-01-19

    We study rapidly accelerating rupture fronts at the onset of frictional motion by performing high-temporal-resolution measurements of both the real contact area and the strain fields surrounding the propagating rupture tip. We observe large-amplitude and localized shear stress peaks that precede rupture fronts and propagate at the shear-wave speed. These localized stress waves, which retain a well-defined form, are initiated during the rapid rupture acceleration phase. They transport considerable energy and are capable of nucleating a secondary supershear rupture. The amplitude of these localized waves roughly scales with the dynamic stress drop and does not decrease as long as the rupture front driving it continues to propagate. Only upon rupture arrest does decay initiate, although the stress wave both continues to propagate and retains its characteristic form. These experimental results are qualitatively described by a self-similar model: a simplified analytical solution of a suddenly expanding shear crack. Quantitative agreement with experiment is provided by realistic finite-element simulations that demonstrate that the radiated stress waves are strongly focused in the direction of the rupture front propagation and describe both their amplitude growth and spatial scaling. Our results demonstrate the extensive applicability of brittle fracture theory to fundamental understanding of friction. Implications for earthquake dynamics are discussed. PMID:26729877

  3. Hydrostatic Level Sensors as High Precision Ground Motion Instrumentation for Tevatron and Other Energy Frontier Accelerators

    SciTech Connect

    Volk, James; Hansen, Sten; Johnson, Todd; Jostlein, Hans; Kiper, Terry; Shiltsev, Vladimir; Chupyra, Andrei; Kondaurov, Mikhail; Medvedko, Anatoly; Parkhomchuk, Vasily; Singatulin, Shavkat

    2012-01-01

    Particle accelerators require very tight tolerances on the alignment and stability of their elements: magnets, accelerating cavities, vacuum chambers, etc. In this article we describe the Hydrostatic Level Sensors (HLS) for very low frequency measurements used in a variety of facilities at Fermilab. We present design features of the sensors, outline their technical parameters, describe their test and calibration procedures, discuss different regimes of operation and give few illustrative examples of the experimental data. Detail experimental results of the ground motion measurements with these detectors will be presented in subsequent papers.

  4. Monte Carlo simulation of peak-acceleration attenuation using a finite-fault uniform-patch model including isochrone and extremal characteristics

    USGS Publications Warehouse

    Rogers, A.M.; Perkins, D.M.

    1996-01-01

    A finite-fault statistical model of the earthquake source is used to confirm observed magnitude and distance saturation scaling in a large peak-acceleration data set. This model allows us to determine the form of peak-acceleration attenuation curves without a priori assumptions about their shape or scaling properties. The source is composed of patches having uniform size and statistical properties. The primary source parameters are the patch peak-acceleration distribution mean, the distribution standard deviation, the patch size, and patch-rupture duration. Although our model assumes no scaling of peak acceleration with magnitude at the patch, the peak-acceleration attenuation curves, nevertheless, strongly scale with magnitude (dap/dM) ??? 0, and the scaling is distance dependent (dap/dM) ??? f(r). The distance-dependent magnitude scaling arises from two principal sources in the model. For a propagating rupture, loci exist on the fault from which radiated energy arrives at a particular station at the same time. These loci are referred to as isochrones. As fault size increases, the length of the isochrones and, hence, the number of additive pulses increase. Thus, peak accelerations increase with magnitude. The second effect, which arises in a completely different manner, is due to extreme-value properties. That is, as the fault size increases, the number of patches on the fault and the number of peak values at the station increase. Because these attenuated pulses are produced by a statistical distribution at the patch, the largest value will depend on the total number of peak values available on the seismogram. We refer to this result as the extremal effect, because it is predicted by the theory of extreme values. Both the extremal and isochrone effects are moderated by attenuation and distance to the fault, leading to magnitude- and distance-dependent peak-acceleration scaling. Remarkably, the scaling produced by both effects is very similar, although the

  5. Will Arctic ground squirrels impede or accelerate climate-induced vegetation changes to the Arctic tundra?

    NASA Astrophysics Data System (ADS)

    Dalton, J.; Flower, C. E.; Brown, J.; Gonzalez-Meler, M. A.; Whelan, C.

    2014-12-01

    Considerable attention has been given to the climate feedbacks associated with predicted vegetation shifts in the Arctic tundra in response to global environmental change. However, little is known regarding the extent to which consumers can facilitate or respond to shrub expansion. Arctic ground squirrels, the largest and most northern ground squirrel, are abundant and widespread throughout the North American tundra. Their broad diet of seeds, flowers, herbage, bird's eggs and meat speaks to the need to breed, feed, and fatten in a span of some 12-16 weeks that separate their 8-9 month bouts of hibernation with the potential consequence to impact ecosystem dynamics. Therefore Arctic ground squirrels are a good candidate to evaluate whether consumers are mere responders (bottom-up effects) or drivers (top-down) of the observed and predicted vegetation changes. As a start towards this question, we measured the foraging intensity (giving-up densities) of Arctic ground squirrels in experimental food patches within which the squirrels experience diminishing returns as they seek the raisins and peanuts that we provided at the Toolik Lake field station in northern Alaska. If the squirrels show their highest feeding intensity in the shrubs, they may impede vegetation shifts by slowing the establishment and expansion of shrubs in the tundra. Conversely, if they show their lowest feeding intensity within shrub dominated areas, they may accelerate vegetation shifts. We found neither. Feeding intensity varied most among transects and times of day, and least along a tundra-to-shrub vegetation gradient. This suggests that the impacts of squirrels will be heterogeneous - in places responders and in others drivers. We should not be surprised then to see patches of accelerated and impeded vegetation changes in the tundra ecosystem. Some of these patterns may be predictable from the foraging behavior of Arctic ground squirrels.

  6. Commissioning of the first drift tube linac module in the Ground Test Accelerator

    SciTech Connect

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Cole, R.; Connolly, R.; Denney, P.; Erickson, J.; Gilpatrick, J.D.; Ingalls, W.B.; Kersteins, D.; Kraus, R.; Lysenko, W.P.; McMurry, D.; Mottershead, C.T.; Power, J.; Rose, C.; Rusthoi, D.P.; Sandoval, D.P.; Schneider, J.D.; Smith, M.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1993-06-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology required for producing high-brightness, high-current H{sup {minus}} beams. GTA commissioning is staged to verify the beam-dynamics design of each major accelerator component as it is brought on-line. The major components are the 35-keV H{sup {minus}} injector, the 2.5-MeV radio-frequency quadrupole (RFQ), the intertank matching section (IMS), the 3.2 MeV first 2{beta}{lambda} drift tube linac (DTL-1) module, and the 24-MeV GTA with 10 DTL modules. Results from the DTL-1 beam experiments will be presented.

  7. ELECTRON AND PROTON ACCELERATION DURING THE FIRST GROUND LEVEL ENHANCEMENT EVENT OF SOLAR CYCLE 24

    SciTech Connect

    Li, C.; Sun, L. P.; Firoz, Kazi A.; Miroshnichenko, L. I.

    2013-06-10

    High-energy particles were recorded by near-Earth spacecraft and ground-based neutron monitors (NMs) on 2012 May 17. This event was the first ground level enhancement (GLE) of solar cycle 24. In this study, we try to identify the acceleration source(s) of solar energetic particles by combining in situ particle measurements from the WIND/3DP, GOES 13, and solar cosmic rays registered by several NMs, as well as remote-sensing solar observations from SDO/AIA, SOHO/LASCO, and RHESSI. We derive the interplanetary magnetic field (IMF) path length (1.25 {+-} 0.05 AU) and solar particle release time (01:29 {+-} 00:01 UT) of the first arriving electrons by using their velocity dispersion and taking into account contamination effects. We found that the electron impulsive injection phase, indicated by the dramatic change in the spectral index, is consistent with flare non-thermal emission and type III radio bursts. Based on the potential field source surface concept, modeling of the open-field lines rooted in the active region has been performed to provide escape channels for flare-accelerated electrons. Meanwhile, relativistic protons are found to be released {approx}10 minutes later than the electrons, assuming their scatter-free travel along the same IMF path length. Combining multi-wavelength imaging data of the prominence eruption and coronal mass ejection (CME), we obtain evidence that GLE protons, with an estimated kinetic energy of {approx}1.12 GeV, are probably accelerated by the CME-driven shock when it travels to {approx}3.07 solar radii. The time-of-maximum spectrum of protons is typical for shock wave acceleration.

  8. Electron and Proton Acceleration during the First Ground Level Enhancement Event of Solar Cycle 24

    NASA Astrophysics Data System (ADS)

    Li, C.; Firoz, Kazi A.; Sun, L. P.; Miroshnichenko, L. I.

    2013-06-01

    High-energy particles were recorded by near-Earth spacecraft and ground-based neutron monitors (NMs) on 2012 May 17. This event was the first ground level enhancement (GLE) of solar cycle 24. In this study, we try to identify the acceleration source(s) of solar energetic particles by combining in situ particle measurements from the WIND/3DP, GOES 13, and solar cosmic rays registered by several NMs, as well as remote-sensing solar observations from SDO/AIA, SOHO/LASCO, and RHESSI. We derive the interplanetary magnetic field (IMF) path length (1.25 ± 0.05 AU) and solar particle release time (01:29 ± 00:01 UT) of the first arriving electrons by using their velocity dispersion and taking into account contamination effects. We found that the electron impulsive injection phase, indicated by the dramatic change in the spectral index, is consistent with flare non-thermal emission and type III radio bursts. Based on the potential field source surface concept, modeling of the open-field lines rooted in the active region has been performed to provide escape channels for flare-accelerated electrons. Meanwhile, relativistic protons are found to be released ~10 minutes later than the electrons, assuming their scatter-free travel along the same IMF path length. Combining multi-wavelength imaging data of the prominence eruption and coronal mass ejection (CME), we obtain evidence that GLE protons, with an estimated kinetic energy of ~1.12 GeV, are probably accelerated by the CME-driven shock when it travels to ~3.07 solar radii. The time-of-maximum spectrum of protons is typical for shock wave acceleration.

  9. Acceleration capability in elite sprinters and ground impulse: Push more, brake less?

    PubMed

    Morin, Jean-Benoît; Slawinski, Jean; Dorel, Sylvain; de Villareal, Eduardo Saez; Couturier, Antoine; Samozino, Pierre; Brughelli, Matt; Rabita, Giuseppe

    2015-09-18

    Overground sprint studies have shown the importance of net horizontal ground reaction force impulse (IMPH) for acceleration performance, but only investigated one or two steps over the acceleration phase, and not in elite sprinters. The main aim of this study was to distinguish between propulsive (IMPH+) and braking (IMPH-) components of the IMPH and seek whether, for an expected higher IMPH, faster elite sprinters produce greater IMPH+, smaller IMPH-, or both. Nine high-level sprinters (100-m best times range: 9.95-10.60s) performed 7 sprints (2×10 m, 2×15 m, 20 m, 30 m and 40 m) during which ground reaction force was measured by a 6.60 m force platform system. By placing the starting-blocks further from the force plates at each trial, and pooling the data, we could assess the mechanics of an entire "virtual" 40-m acceleration. IMPH and IMPH+ were significantly correlated with 40-m mean speed (r=0.868 and 0.802, respectively; P<0.01), whereas vertical impulse and IMPH- were not. Multiple regression analyses confirmed the significantly higher importance of IMPH+ for sprint acceleration performance. Similar results were obtained when considering these mechanical data averaged over the first half of the sprint, but not over the second half. In conclusion, faster sprinters were those who produced the highest amounts of horizontal net impulse per unit body mass, and those who "pushed more" (higher IMPH+), but not necessarily those who also "braked less" (lower IMPH-) in the horizontal direction. PMID:26209876

  10. Simulation and steering in the intertank matching section of the ground test accelerator

    SciTech Connect

    Yuan, V.W.; Bolme, G.O.; Johnson, K.F.; Mottershead, C.T.; Sander, O.R.; Smith, M.T.; Erickson, J.L.

    1994-10-01

    The Intertank Matching Section (IMS) of the Ground Test Accelerator (GTA) is a short (36 cm) beamline designed to match the Radio Frequency Quadrupole (RFQ) exit beam into the first Drift Tube LINAC (DTL) tank. The IMS contains two steering quadrupoles (SMQs) and four variable-field focussing quads (VFQs). The SMQs are fixed strength permanent magnet quadrupoles on mechanical actuators capable of transverse movement for the purpose of steering the beam. The upstream and downstream steering quadrupoles are labelled SMQ1 and SMQ4 respectively. Also contained in the IMS are two RF cavities for longitudinal matching.

  11. Simulation and steering in the Intertank matching section of the ground test accelerator

    NASA Astrophysics Data System (ADS)

    Yuan, V. W.; Bolme, G. O.; Erickson, J. L.; Johnson, K. F.; Mottershead, C. T.; Sander, O. R.; Smith, M. T.

    1995-05-01

    The Intertank Matching Section (IMS) of the Ground Test Accelerator (GTA) is a short (36 cm) beamline designed to match the Radio Frequency Quadrupole (RFQ) exit beam into the first Drift Tube LINAC (DTL) tank. The IMS contains two steering quadrupoles (SMQS) and four variable-field focusing quads (VFQs). The SMQs are fixed strength permanent magnet quadrupoles on mechanical actuators capable of transverse movement for the purpose of steerng the beam. Also contained in the IMS are two RF cavities for longitudinal matching. A comparison of measured to calculated steering coefficients has been made for data aken in 3 different tunes of the IMS transport line. (AIP)

  12. Ground Test of the Urine Processing Assembly for Accelerations and Transfer Functions

    NASA Technical Reports Server (NTRS)

    Houston, Janice; Almond, Deborah F. (Technical Monitor)

    2001-01-01

    This viewgraph presentation gives an overview of the ground test of the urine processing assembly for accelerations and transfer functions. Details are given on the test setup, test data, data analysis, analytical results, and microgravity assessment. The conclusions of the tests include the following: (1) the single input/multiple output method is useful if the data is acquired by tri-axial accelerometers and inputs can be considered uncorrelated; (2) tying coherence with the matrix yields higher confidence in results; (3) the WRS#2 rack ORUs need to be isolated; (4) and future work includes a plan for characterizing performance of isolation materials.

  13. The acoustic signatures of ground acceleration, gas expansion, and spall fallback in experimental volcanic explosions

    NASA Astrophysics Data System (ADS)

    Bowman, Daniel C.; Taddeucci, Jacopo; Kim, Keehoon; Anderson, Jacob F.; Lees, Jonathan M.; Graettinger, Alison H.; Sonder, Ingo; Valentine, Greg A.

    2014-03-01

    Infrasound and high-speed imaging during a series of field-scale buried explosions suggest new details about the generation and radiation patterns of acoustic waves from volcanic eruptions. We recorded infrasound and high-speed video from a series of subsurface explosions with differing burial depths and charge sizes. Joint observations and modeling allow the extraction of acoustic energy related to the magnitude of initial ground deformation, the contribution of gas breakout, and the timing of the fallback of displaced material. The existence and relative acoustic amplitudes of these three phases depended on the size and depth of the explosion. The results motivate a conceptual model that relates successive contributions from ground acceleration, gas breakout, and spall fallback to the acoustic amplitude and waveform characteristics of buried explosions. We place the literature on infrasound signals at Santiaguito Volcano, Guatemala, and Sakurajima and Suwonosejima Volcanoes, Japan, in the context of this model.

  14. Feasibility study of a nonequilibrium MHD accelerator concept for hypersonic propulsion ground testing

    SciTech Connect

    Lee, Ying-Ming; Simmons, G.A.; Nelson, G.L.

    1995-12-31

    A National Aeronautics and Space Administration (NASA) funded research study to evaluate the feasibility of using magnetohydrodynamic (MHD) body force accelerators to produce true air simulation for hypersonic propulsion ground testing is discussed in this paper. Testing over the airbreathing portion of a transatmospheric vehicle (TAV) hypersonic flight regime will require high quality air simulation for actual flight conditions behind a bow shock wave (forebody, pre-inlet region) for flight velocities up to Mach 16 and perhaps beyond. Material limits and chemical dissociation at high temperature limit the simulated flight Mach numbers in conventional facilities to less than Mach 12 for continuous and semi-continuous testing and less than Mach 7 for applications requiring true air chemistry. By adding kinetic energy directly to the flow, MHD accelerators avoid the high temperatures and pressures required in the reservoir region of conventional expansion facilities, allowing MHD to produce true flight conditions in flight regimes impossible with conventional facilities. The present study is intended to resolve some of the critical technical issues related to the operation of MHD at high pressure. Funding has been provided only for the first phase of a three to four year feasibility study that would culminate in the demonstration of MHD acceleration under conditions required to produce true flight conditions behind a bow shock wave to flight Mach numbers of 16 or greater. MHD critical issues and a program plan to resolve these are discussed.

  15. Stochastic shock response spectrum decomposition method based on probabilistic definitions of temporal peak acceleration, spectral energy, and phase lag distributions of mechanical impact pyrotechnic shock test data

    NASA Astrophysics Data System (ADS)

    Hwang, James Ho-Jin; Duran, Adam

    2016-08-01

    Most of the times pyrotechnic shock design and test requirements for space systems are provided in Shock Response Spectrum (SRS) without the input time history. Since the SRS does not describe the input or the environment, a decomposition method is used to obtain the source time history. The main objective of this paper is to develop a decomposition method producing input time histories that can satisfy the SRS requirement based on the pyrotechnic shock test data measured from a mechanical impact test apparatus. At the heart of this decomposition method is the statistical representation of the pyrotechnic shock test data measured from the MIT Lincoln Laboratory (LL) designed Universal Pyrotechnic Shock Simulator (UPSS). Each pyrotechnic shock test data measured at the interface of a test unit has been analyzed to produce the temporal peak acceleration, Root Mean Square (RMS) acceleration, and the phase lag at each band center frequency. Maximum SRS of each filtered time history has been calculated to produce a relationship between the input and the response. Two new definitions are proposed as a result. The Peak Ratio (PR) is defined as the ratio between the maximum SRS and the temporal peak acceleration at each band center frequency. The ratio between the maximum SRS and the RMS acceleration is defined as the Energy Ratio (ER) at each band center frequency. Phase lag is estimated based on the time delay between the temporal peak acceleration at each band center frequency and the peak acceleration at the lowest band center frequency. This stochastic process has been applied to more than one hundred pyrotechnic shock test data to produce probabilistic definitions of the PR, ER, and the phase lag. The SRS is decomposed at each band center frequency using damped sinusoids with the PR and the decays obtained by matching the ER of the damped sinusoids to the ER of the test data. The final step in this stochastic SRS decomposition process is the Monte Carlo (MC

  16. Multi-component ground motion response spectra for coupled horizontal, vertical, angular accelerations, and tilt

    USGS Publications Warehouse

    Kalkan, E.; Graizer, V.

    2007-01-01

    Rotational and vertical components of ground motion are almost always ignored in design or in the assessment of structures despite the fact that vertical motion can be twice as much as the horizontal motion and may exceed 2g level, and rotational excitation may reach few degrees in the proximity of fault rupture. Coupling of different components of ground excitation may significantly amplify the seismic demand by introducing additional lateral forces and enhanced P-?? effects. In this paper, a governing equation of motion is postulated to compute the response of a SDOF oscillator under a multi-component excitation. The expanded equation includes secondary P-?? components associated with the combined impacts of tilt and vertical excitations in addition to the inertial forcing terms due to the angular and translational accelerations. The elastic and inelastic spectral ordinates traditionally generated considering the uniaxial input motion are compared at the end with the multi-component response spectra of coupled horizontal, vertical and tilting motions. The proposed multi-component response spectrum reflects kinematic characteristics of the ground motion that are not identifiable by the conventional spectrum itself, at least for the near-fault region where high intensity vertical shaking and rotational excitation are likely to occur.

  17. The dependence of peak horizontal acceleration on magnitude, distance, and site effects for small-magnitude earthquakes in California and eastern North America

    USGS Publications Warehouse

    Campbell, K.W.

    1989-01-01

    One-hundred and ninety free-field accelerograms recorded on deep soil (>10 m deep) were used to study the near-source scaling characteristics of peak horizontal acceleration for 91 earthquakes (2.5 ??? ML ??? 5.0) located primarily in California. An analysis of residuals based on an additional 171 near-source accelerograms from 75 earthquakes indicated that accelerograms recorded in building basements sited on deep soil have 30 per cent lower acclerations, and that free-field accelerograms recorded on shallow soil (???10 m deep) have 82 per cent higher accelerations than free-field accelerograms recorded on deep soil. An analysis of residuals based on 27 selected strong-motion recordings from 19 earthquakes in Eastern North America indicated that near-source accelerations associated with frequencies less than about 25 Hz are consistent with predictions based on attenuation relationships derived from California. -from Author

  18. Quasimonoenergetic Proton Bunch Generation by Dual-Peaked Electrostatic-Field Acceleration in Foils Irradiated by an Intense Linearly Polarized Laser

    NASA Astrophysics Data System (ADS)

    Zhuo, H. B.; Chen, Z. L.; Yu, W.; Sheng, Z. M.; Yu, M. Y.; Jin, Z.; Kodama, R.

    2010-08-01

    It is found that stable proton acceleration from a thin foil irradiated by a linearly polarized ultraintense laser can be realized for appropriate foil thickness and laser intensity. A dual-peaked electrostatic field, originating from the oscillating and nonoscillating components of the laser ponderomotive force, is formed around the foil surfaces. This field combines radiation-pressure acceleration and target normal sheath acceleration to produce a single quasimonoenergetic ion bunch. A criterion for this mechanism to be operative is obtained and verified by two-dimensional particle-in-cell simulation. At a laser intensity of ˜5.5×1022W/cm2, quasimonoenergetic GeV proton bunches are obtained with ˜100MeV energy spread, less than 4° spatial divergence, and ˜50% energy conversion efficiency from the laser.

  19. TriNet "ShakeMaps": Rapid generation of peak ground motion and intensity maps for earthquakes in southern California

    USGS Publications Warehouse

    Wald, D.J.; Quitoriano, V.; Heaton, T.H.; Kanamori, H.; Scrivner, C.W.; Worden, C.B.

    1999-01-01

    Rapid (3-5 minutes) generation of maps of instrumental ground-motion and shaking intensity is accomplished through advances in real-time seismographic data acquisition combined with newly developed relationships between recorded ground-motion parameters and expected shaking intensity values. Estimation of shaking over the entire regional extent of southern California is obtained by the spatial interpolation of the measured ground motions with geologically based frequency and amplitude-dependent site corrections. Production of the maps is automatic, triggered by any significant earthquake in southern California. Maps are now made available within several minutes of the earthquake for public and scientific consumption via the World Wide Web; they will be made available with dedicated communications for emergency response agencies and critical users.

  20. Final safety analysis report for the Ground Test Accelerator (GTA), Phase 2

    SciTech Connect

    1994-10-01

    This document is the first volume of a 3 volume safety analysis report on the Ground Test Accelerator (GTA). The GTA program at the Los Alamos National Laboratory (LANL) is the major element of the national Neutral Particle Beam (NPB) program, which is supported by the Strategic Defense Initiative Office (SDIO). A principal goal of the national NPB program is to assess the feasibility of using hydrogen and deuterium neutral particle beams outside the Earth`s atmosphere. The main effort of the NPB program at Los Alamos concentrates on developing the GTA. The GTA is classified as a low-hazard facility, except for the cryogenic-cooling system, which is classified as a moderate-hazard facility. This volume consists of an introduction, summary/conclusion, site description and assessment, description of facility, and description of operation.

  1. Final safety analysis report for the Ground Test Accelerator (GTA), Phase 2

    SciTech Connect

    1994-10-01

    This document is the third volume of a 3 volume safety analysis report on the Ground Test Accelerator (GTA). The GTA program at the Los Alamos National Laboratory (LANL) is the major element of the national Neutral Particle Beam (NPB) program, which is supported by the Strategic Defense Initiative Office (SDIO). A principal goal of the national NPB program is to assess the feasibility of using hydrogen and deuterium neutral particle beams outside the Earth`s atmosphere. The main effort of the NPB program at Los Alamos concentrates on developing the GTA. The GTA is classified as a low-hazard facility, except for the cryogenic-cooling system, which is classified as a moderate-hazard facility. This volume consists of appendices C through U of the report

  2. Simulation and steering in the Intertank matching section of the ground test accelerator

    SciTech Connect

    Yuan, V.W.; Bolme, G.O.; Erickson, J.L.; Johnson, K.F.; Mottershead, C.T.; Sander, O.R.; Smith, M.T.

    1995-05-05

    The Intertank Matching Section (IMS) of the Ground Test Accelerator (GTA) is a short (36 cm) beamline designed to match the Radio Frequency Quadrupole (RFQ) exit beam into the first Drift Tube LINAC (DTL) tank. The IMS contains two steering quadrupoles (SMQS) and four variable-field focusing quads (VFQs). The SMQs are fixed strength permanent magnet quadrupoles on mechanical actuators capable of transverse movement for the purpose of steerng the beam. Also contained in the IMS are two RF cavities for longitudinal matching. A comparison of measured to calculated steering coefficients has been made for data aken in 3 different tunes of the IMS transport line. (AIP) {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  3. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground-Based Accelerators.

    PubMed

    Kim, Myung-Hee Y; Rusek, Adam; Cucinotta, Francis A

    2015-01-01

    For radiobiology research on the health risks of galactic cosmic rays (GCR) ground-based accelerators have been used with mono-energetic beams of single high charge, Z and energy, E (HZE) particles. In this paper, we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL), we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model) to define a GCR reference field using 9 HZE particle beam-energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and (4)He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However, a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation, with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving knowledge of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology research. PMID:26090339

  4. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground-Based Accelerators

    PubMed Central

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis A.

    2015-01-01

    For radiobiology research on the health risks of galactic cosmic rays (GCR) ground-based accelerators have been used with mono-energetic beams of single high charge, Z and energy, E (HZE) particles. In this paper, we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL), we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model) to define a GCR reference field using 9 HZE particle beam–energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and 4He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However, a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation, with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving knowledge of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology research. PMID:26090339

  5. Performance report on the ground test accelerator radio-frequency quadrupole

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Cole, R.; Connolly, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.

    1994-09-01

    The Ground Test Accelerator (GTA) uses a radio-frequency quadrupole (RFQ) to bunch and accelerate a 35 keV input beam to a final energy of 2.5 MeV. Most measured parameters of the GTA RFQ agreed with simulated predictions. The relative shape of the transmission versus the vane-voltage relationship and the Courant-Snyder (CS) parameters of the output beam`s transverse and longitudinal phase spaces agreed well with predictions. However, the transmission of the RFQ was significantly lower than expected. Improved simulation studies included image charges and multipole effects in the RFQ. Most of the predicted properties of the RFQ, such as input matched-beam conditions and output-beam shapes were unaffected by these additional effects. However, the comparison of measured with predicted absolute values of transmitted beam was much improved by the inclusion of these effects in the simulations. The comparison implied a value for the input emittance that is consistent with measurements.

  6. Small Ground-Level Enhancement of 6 January 2014: Acceleration by CME-Driven Shock?

    NASA Astrophysics Data System (ADS)

    Li, C.; Miroshnichenko, L. I.; Sdobnov, V. E.

    2016-03-01

    Available spectral data for solar energetic particles (SEPs) measured near the Earth's orbit (GOES-13) and on the terrestrial surface (polar neutron monitors) on 6 January 2014 are analyzed. A feature of this solar proton event (SPE) and weak ground-level enhancement (GLE) is that the source was located behind the limb. For the purpose of comparison, we also use the Advanced Composition Explorer (ACE) data on sub-relativistic electrons and GOES-13 measurements of a strong and extended proton event on 8 - 9 January 2014. It was found that the surface observations at energies {>} 433 MeV and GOES-13 data at {>} 30 - {>} 700 MeV may be satisfactorily reconciled by a power-law time-of-maximum (TOM) spectrum with a characteristic exponential tail (cutoff). Some methodological difficulties of spectrum determination are discussed. Assuming that the TOM spectrum near the Earth is a proxy of the spectrum of accelerated particles in the source, we critically consider the possibility of shock acceleration to relativistic energies in the solar corona. Finally, it is suggested to interpret the observational features of this GLE under the assumption that small GLEs may be produced by shocks driven by coronal mass ejections. However, the serious limitations of such an approach to the problem of the SCR spectrum prevent drawing firm conclusions in this controversial field.

  7. X-class Solar Flare Energy Partition into Radiative, Non-Thermal Acceleration of Electrons and Peak Thermal Plasma Components - Methodology and Results

    NASA Astrophysics Data System (ADS)

    Moore, Christopher S.; Chamberlin, Phillip; Dennis, Brian R.; Hock, Rachel

    2015-08-01

    Solar flares are among the most energetic processes in the solar system. X-class flares are the largest and can convert up to 1033 ergs of magnetic energy into the acceleration of charged particles and the heating of plasma. They are often accompanied by coronal mass ejections (CMEs). We discuss the methodology and results of the energy partition into three main components: (1) radiative energy, (2) non-thermal acceleration of electrons, and (3) the peak thermal energy content, for a subset of the largest eruptive events from Solar Cycle 23, as derived from satellite observations and empirical models. The bolometric energy content is on the order of 1031 - 1032 ergs and is extracted from Total Solar Irradiance (TSI) measurements by the Total Irradiance Monitor (TIM) onboard the SOlar Radiation and Climate Experiment (SORCE). The Vacuum Ultraviolet (VUV) contribution of the total radiative output is obtained by implementing the Flare Irradiance Spectral Model (FISM). Furthermore, we partition the radiative release into impulsive and gradual phases. X-ray spectra from the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) are used to deduce the energy in the non-thermal accelerated electrons, generally found to be 1031 -1032 ergs, and the peak thermal energy content of around 1030 - 1031 ergs. Aside from the CME kinetic energy, these three components contain a substantial amount of the initial available magnetic energy.

  8. Effective generation of the spread-out-Bragg peak from the laser accelerated proton beams using a carbon-proton mixed target.

    PubMed

    Yoo, Seung Hoon; Cho, Ilsung; Cho, Sungho; Song, Yongkeun; Jung, Won-Gyun; Kim, Dae-Hyun; Shin, Dongho; Lee, Se Byeong; Pae, Ki-Hong; Park, Sung Yong

    2014-12-01

    Conventional laser accelerated proton beam has broad energy spectra. It is not suitable for clinical use directly, so it is necessary for employing energy selection system. However, in the conventional laser accelerated proton system, the intensity of the proton beams in the low energy regime is higher than that in the high energy regime. Thus, to generate spread-out-Bragg peak (SOBP), stronger weighting value to the higher energy proton beams is needed and weaker weighting value to the lower energy proton beams is needed, which results in the wide range of weighting values. The purpose of this research is to investigate a method for efficient generating of the SOBP with varying magnetic field in the energy selection system using a carbon-proton mixture target. Energy spectrum of the laser accelerated proton beams was acquired using Particle-In-Cell simulations. The Geant4 Monte Carlo simulation toolkit was implemented for energy selection, particle transportation, and dosimetric property measurement. The energy selection collimator hole size of the energy selection system was changed from 1 to 5 mm in order to investigate the effect of hole size on the dosimetric properties for Bragg peak and SOBP. To generate SOBP, magnetic field in the energy selection system was changed during beam irradiation with each beam weighting factor. In this study, our results suggest that carbon-proton mixture target based laser accelerated proton beams can generate quasi-monoenergetic energy distribution and result in the efficient generation of SOBP. A further research is needed to optimize SOBP according to each range and modulated width using an optimized weighting algorithm. PMID:25154880

  9. A high peak power S-band switching system for the Advanced Photon Source (APS) Linear Accelerator (Linac).

    SciTech Connect

    Grelick, A. E.

    1998-09-11

    An S-band linear accelerator is the source of particles and front end of the Advanced Photon Source [1] injector. Additionally, it will be used to support a low-energy undulator test line (LEUTL) and to drive a free-electron laser (FEL). To provide maximum linac availability for all uses, an additional modulator-klystron subsystem has been built,and a waveguide-switching and distribution subsystem is now under construction. The combined subsystems provide a hot spare for any of the five S-band transmitters that power the lina cand have been given the additional function of powering an rf gun test stand whenever they are not otherwise needed. Design considerations for the waveguide-switching subsystem, topology selection, timing, control, and system protection provisions are described.

  10. Mixed-field GCR Simulations for Radiobiological Research using Ground Based Accelerators

    NASA Astrophysics Data System (ADS)

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis

    Space radiation is comprised of a large number of particle types and energies, which have differential ionization power from high energy protons to high charge and energy (HZE) particles and secondary neutrons produced by galactic cosmic rays (GCR). Ground based accelerators such as the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) are used to simulate space radiation for radiobiology research and dosimetry, electronics parts, and shielding testing using mono-energetic beams for single ion species. As a tool to support research on new risk assessment models, we have developed a stochastic model of heavy ion beams and space radiation effects, the GCR Event-based Risk Model computer code (GERMcode). For radiobiological research on mixed-field space radiation, a new GCR simulator at NSRL is proposed. The NSRL-GCR simulator, which implements the rapid switching mode and the higher energy beam extraction to 1.5 GeV/u, can integrate multiple ions into a single simulation to create GCR Z-spectrum in major energy bins. After considering the GCR environment and energy limitations of NSRL, a GCR reference field is proposed after extensive simulation studies using the GERMcode. The GCR reference field is shown to reproduce the Z and LET spectra of GCR behind shielding within 20 percents accuracy compared to simulated full GCR environments behind shielding. A major challenge for space radiobiology research is to consider chronic GCR exposure of up to 3-years in relation to simulations with cell and animal models of human risks. We discuss possible approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks and fractionation approaches at a GCR simulator.

  11. Mixed-field GCR Simulations for Radiobiological Research Using Ground Based Accelerators

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis A.

    2014-01-01

    Space radiation is comprised of a large number of particle types and energies, which have differential ionization power from high energy protons to high charge and energy (HZE) particles and secondary neutrons produced by galactic cosmic rays (GCR). Ground based accelerators such as the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) are used to simulate space radiation for radiobiology research and dosimetry, electronics parts, and shielding testing using mono-energetic beams for single ion species. As a tool to support research on new risk assessment models, we have developed a stochastic model of heavy ion beams and space radiation effects, the GCR Event-based Risk Model computer code (GERMcode). For radiobiological research on mixed-field space radiation, a new GCR simulator at NSRL is proposed. The NSRL-GCR simulator, which implements the rapid switching mode and the higher energy beam extraction to 1.5 GeV/u, can integrate multiple ions into a single simulation to create GCR Z-spectrum in major energy bins. After considering the GCR environment and energy limitations of NSRL, a GCR reference field is proposed after extensive simulation studies using the GERMcode. The GCR reference field is shown to reproduce the Z and LET spectra of GCR behind shielding within 20% accuracy compared to simulated full GCR environments behind shielding. A major challenge for space radiobiology research is to consider chronic GCR exposure of up to 3-years in relation to simulations with cell and animal models of human risks. We discuss possible approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks and fractionation approaches at a GCR simulator.

  12. An accelerated remedial strategy developed for J-Field, Aberdeen Proving Ground, Maryland

    SciTech Connect

    Yuen, C.R.; Martino, L.; Patton, T.; Wrobel, J.

    1995-06-01

    For an installation with many disposal sites and multiple contaminant sources, successful remediation at minimum cost can be complicated by insufficient geologic and hydrogeologic information, incomplete records of historical disposal activities, and uncertainty about the effectiveness of different investigative methods. To reduce these uncertainties and to increase the probability of successful remediation at minimum cost, a ``Phased and pilot`` accelerated remedial strategy has been developed for the J-Field area of Aberdeen Proving Ground, Maryland. The strategy includes four phases. First, the most contaminated site is selected as a pilot for detailed investigation. Second, the most contaminated areas within the pilot site are chosen as a pilot source area for interim action study, and a remedial action is developed to remove the primary contaminant sources. The subsequent sitewide investigation uses the effective tools developed in the first phase. Third, a cleanup operation is initiated in the pilot source area, while a sitewide feasibility study is developed by taking advantage of lessons learned in the interim action. Fourth, a sitewide cleanup operation proceeds.

  13. Image processing and computer controls for video profile diagnostic system in the ground test accelerator (GTA)

    SciTech Connect

    Wright, R.M.; Zander, M.E.; Brown, S.K.; Sandoval, D.P.; Gilpatrick, J.D.; Gibson, H.E.

    1992-09-01

    This paper describes the application of video image processing to beam profile measurements on the Ground Test Accelerator (GTA). A diagnostic was needed to measure beam profiles in the intermediate matching section (IMS) between the radio-frequency quadrupole (RFQ) and the drift tube linac (DTL). Beam profiles are measured by injecting puffs of gas into the beam. The light emitted from the beam-gas interaction is captured and processed by a video image processing system, generating the beam profile data. A general purpose, modular and flexible video image processing system, imagetool, was used for the GTA image profile measurement. The development of both software and hardware for imagetool and its integration with the GTA control system (GTACS) will be discussed. The software includes specialized algorithms for analyzing data and calibrating the system. The underlying design philosophy of imagetool was tested by the experience of building and using the system, pointing the way for future improvements. The current status of the system will be illustrated by samples of experimental data.

  14. Image processing and computer controls for video profile diagnostic system in the ground test accelerator (GTA)

    SciTech Connect

    Wright, R.M.; Zander, M.E.; Brown, S.K.; Sandoval, D.P.; Gilpatrick, J.D.; Gibson, H.E.

    1992-01-01

    This paper describes the application of video image processing to beam profile measurements on the Ground Test Accelerator (GTA). A diagnostic was needed to measure beam profiles in the intermediate matching section (IMS) between the radio-frequency quadrupole (RFQ) and the drift tube linac (DTL). Beam profiles are measured by injecting puffs of gas into the beam. The light emitted from the beam-gas interaction is captured and processed by a video image processing system, generating the beam profile data. A general purpose, modular and flexible video image processing system, imagetool, was used for the GTA image profile measurement. The development of both software and hardware for imagetool and its integration with the GTA control system (GTACS) will be discussed. The software includes specialized algorithms for analyzing data and calibrating the system. The underlying design philosophy of imagetool was tested by the experience of building and using the system, pointing the way for future improvements. The current status of the system will be illustrated by samples of experimental data.

  15. Final safety analysis report for the Ground Test Accelerator (GTA), Phase 2

    SciTech Connect

    1994-10-01

    This document is the second volume of a 3 volume safety analysis report on the Ground Test Accelerator (GTA). The GTA program at the Los Alamos National Laboratory (LANL) is the major element of the national Neutral Particle Beam (NPB) program, which is supported by the Strategic Defense Initiative Office (SDIO). A principal goal of the national NPB program is to assess the feasibility of using hydrogen and deuterium neutral particle beams outside the Earth`s atmosphere. The main effort of the NPB program at Los Alamos concentrates on developing the GTA. The GTA is classified as a low-hazard facility, except for the cryogenic-cooling system, which is classified as a moderate-hazard facility. This volume consists of failure modes and effects analysis; accident analysis; operational safety requirements; quality assurance program; ES&H management program; environmental, safety, and health systems critical to safety; summary of waste-management program; environmental monitoring program; facility expansion, decontamination, and decommissioning; summary of emergency response plan; summary plan for employee training; summary plan for operating procedures; glossary; and appendices A and B.

  16. Large Ground Level events in solar cycle 22 and some peculiarities of relativistic proton acceleration.

    PubMed

    Vashenyuk, E V; Miroshnichenko, L I; Sorokin, M O; Perez-Peraza, J; Gallegos, A

    1994-10-01

    Some of the Ground Level Enhancements of Solar Cosmic Rays (SCR) recorded by neutron monitors during solar cycle 22 are analyzed. The events appeared in series, and their occurrence rate in 1989-1991 was a factor of 4 larger than the average value (approximately equal to 1/yr) for the total observation interval (since 1942). The events of Sept. 29 and Oct. 24, 1989 proved to be the more intensive. The analyzed events show no peculiarities as to the distribution of the T1/2 parameter, whereas the shape of the profile of some events is notable for a two peak structure. The latter implies the possibility of a two component SCR ejection from two different sources in the solar atmosphere. For the event of Sep. 29 we have estimated the ejection rigidity spectrum of protons to be D solar (R) = (1-2) 10(32)R(-2.9) Gv-1 at R greater than or equal to 1 Gv. As to its proton flux, this event proved to be by 1-2 orders less intensive than the well known event of Feb. 23 1956. PMID:11540014

  17. Assessment of soil and ground-water activation in the underground facility of the linear accelerator at RAON

    NASA Astrophysics Data System (ADS)

    Lee, Sangjin; Nam, Shinwoo; Chung, Yonsei; Kim, Suna; Lee, Cheol Woo

    2015-10-01

    RAON is a heavy-ion accelerator complex that is being constructed in Daejeon, Korea. The superconducting linear accelerator of RAON will provide various heavy-ion beams with a maximum power of 400 kW. In order to determine the design requirements of the underground facility for the accelerator, we considered the radiation's influence on the soil and the ground-water under the condition of long-term operation of the accelerator. A source term for prompt neutrons generated by heavy-ion beams losses along the beam lines at a rate of 1 W/m was applied to obtain the activation level of nearby material outside the tunnel by using the simulation codes MCNPX and SP-FISPACT. This report presents the analysis and the result for the tunnel shielding condition obtained from the assessment.

  18. A new Kinematic Approach to Calculate Seismic Hazard Scenarios (Intensity and Peak Ground Displacement); an Example in SE Sicily

    NASA Astrophysics Data System (ADS)

    Sirovich, L.; Pettenati, F.

    2007-05-01

    The part of the seismic hazard map of Italy (http:zonesismiche.mi.ingv.it/mappa_ps_apr04/italia.html) that regards SE Sicily has recently been modified on the basis also of the new location of the source of one of the strongest earthquakes that ever struck the Mediterranean basin (in 1693 in SE Sicily; 54,000 casualties; see Sirovich and Pettenati, 2001 in BSSA). That source was located inland according to the KF geophysical inversion of the regional damage patterns of the earthquake of Jan. 11, 1693 and of its destructive foreshock of Jan. 9 (see Gentile et al., 2004 in BSSA, and Sirovich and Pettenati, 2004 in JGR, for the genetic KF inversion technique). The damage patterns of Jan. 9 and 11, 1693 had been evaluated by three different groups of historians and seismologists on three different intensity scales. (Detailed information was available from the reports of the Officers of the "Regno delle Due Sicilie" of the time as well as from many other documents). Previously, both earthquakes were traditionally ascribed to the well known Malta Escarpment, the most prominent physiographical and structural feature of the area, which is found offshore, south-east of Sicily. However, given the inland damage of 1693, an offshore epicenter would imply a mean radius of 45 km for the virtual area of degree XI (70 km for degree X) and, thus, a magnitude of 8.3±0.2 with a fault length of approximately 280 km. This fault source would cross the NE part of Sicily from the southern Jonian Sea to the Island of Lipari in the Tyrrhenian Sea; but tectonically this seems unrealistic. All the inversion tests, however, pointed to a complex source inland which could have hosted both earthquakes. Here, we used our kinematic KF model in the direct mode in a parametric, deterministic-Montecarlo way to produce a seismic hazard scenario, in terms of maximum ground displacement. This scenario will be compared with PSHA results for long recurrence times in the frame of a project of the Civil

  19. Natural Paleoseismometers: Cosmogenic Nuclide Dating of Precariously Balanced Rocks (PBRs) - Integral Constraints on Maximum Ground Accelerations

    NASA Astrophysics Data System (ADS)

    Perg, L. A.; Ludwig, L. G.; Kendrick, K.; Brune, J.; Purvance, M.; Anooshehpoor, R.; Akciz, S.

    2007-12-01

    Precariously balanced rocks (PBRs) act as natural seismometers constraining maximum ground acceleration over the surface exposure history of the PBR. These key paleoseismic indicators have the potential to validate ground motions on the timescale necessary to test earthquake rupture forecasts and Seismic Hazard Assessment estimates, and are an active topic of research to validate CyberShake results and constrain National Seismic Hazard Maps. This research focuses on examining the post-exhumation history of PBRs using in-situ terrestrial cosmogenic nuclides (TCNs). TCNs provide a record of near-surface exposure history. The measured concentrations are a function of the residence time in the upper ~20 m of the subsurface (inherited concentration), the timing and rate of exhumation, and post-exhumation surface spalling and chemical erosion. Our goal in the project is to provide reasonable constraints on the post-exhumation history, specifically the age of the PBRs and evolution of precariousness: we should be able to constrain whether the rocks were of similar precariousness 2.5 ka, 5 ka, and 10 ka ago. These specific targets will provide important constraints on time since exceedance for the CyberShake models. We developed our sampling strategy to address subsurface inheritance, exhumation rate and timing, and post- exhumation spalling and chemical erosion. PBRs were selected to meet a variety of considerations. These rocks constrain ground motions from large earthquakes on the San Jacinto and Elsinore faults, in Southern California. Inherited concentrations lead to an age estimate that is too old; we are investigating inherited concentrations though sampling a rock quarry near Perris CA, with shielded samples at greater than 15 m depth. We also have partially shielded samples from the interior of rocks toppled to measure their stability, and through vandalism. To determine exhumation age and rate, our sampling strategy is to collect 5-6 samples per PBR: 1 on top, 3

  20. Analog-to-digital conversion as a source of drifts in displacements derived from digital recordings of ground acceleration

    USGS Publications Warehouse

    Boore, D.M.

    2003-01-01

    Displacements obtained from double integration of digitally recorded ground accelerations often show drifts much larger than those expected for the true ground displacements. These drifts might be due to many things, including dynamic elastic ground tilt, inelastic ground deformation, hysteresis in the instruments, and cross feed due to misalignment of nominally orthogonal sensors. This article shows that even if those effects were not present, the analog-to-digital conversion (ADC) process can produce apparent "pulses" and offsets in the acceleration baseline if the ground motion is slowly varying compared with the quantization level of the digitization. Such slowly varying signals can be produced by constant offsets that do not coincide with a quantization level and by near- and intermediate-field terms in the wave field radiated from earthquakes. Double integration of these apparent pulses and offsets leads to drifts in the displacements similar to those found in processing real recordings. These effects decrease in importance as the resolution of the ADC process increases.

  1. Parametric study of a variable-magnetic-field-based energy-selection system for generating a spread-out Bragg peak with a laser-accelerated proton beam

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Hyun; Suh, Tae-Suk; Kang, Young Nam; Yoo, Seung Hoon; Pae, Ki-Hong; Shin, Dongho; Lee, Se Byeong

    2013-01-01

    Laser-based proton beam acceleration, which produces broad energy spectra, is unsuitable for direct clinical use. Thus, employing an energy selection system is necessary. The purpose of the present study was to investigate a method whereby a variable magnetic field could be employed with an energy selection system to generate a spread-out Bragg peak (SOBP). For energy selection, particle transport and dosimetric property measurements, the Geant4 toolkit was implemented. The energy spectrum of the laser-accelerated proton beam was acquired using a particle-in-cell simulation. The hole size and the position of the energy selection collimator were varied in order to determine the effects of those parameters on the dosimetric properties. To generate an SOBP, we changed the magnetic field in the energy selection system for each beam weighting factor during beam irradiation. The overall results of this study suggest that the use of an energy selection system with a variable magnetic field can effectively generate an SOBP suitable for proton radiation therapy applications.

  2. Estimating double tuned mass dampers for structures under ground acceleration using a novel optimum criterion

    NASA Astrophysics Data System (ADS)

    Li, Chunxiang; Zhu, Bilei

    2006-11-01

    The double tuned mass dampers (DTMD), consisting of one larger mass block (i.e. one larger tuned mass damper (TMD)) and one smaller mass block (i.e. one smaller TMD), have been proposed to seek for the mass dampers with high effectiveness and robustness for the reduction of the undesirable vibrations of structures under the ground acceleration. The structure is represented by the mode-generalized system corresponding to the specific vibration mode that needs to be controlled. In light of the developed dynamic magnification factors (DMF) of the DTMD structure system, the criterion used for assessing the optimum parameters and effectiveness of the DTMD is selected as the minimization of the minimum values of the maximum DMF of the structure with the DTMD. With resorting to the maximum DMF of both the larger and smaller TMDs in the DTMD, the stroke of the DTMD is simultaneously investigated too. It is highlighted that a novel optimum objective function has been proposed in order to acquire high robust control system. Consequently, the two types of optimum goal functions (including the optimum goal function commonly used) have been applied for the optimum searching of the DTMD. The numerical results indicate that the DTMD designed in terms of the second type of optimum objective functions (i.e. the novel optimum objective function) practically provides the same effectiveness and robustness to the changes in the drift frequency ratio (DFR) as the multiple tuned mass dampers (MTMD) with the distributed natural frequencies with the total number of the TMD units equal to five and with equal total mass ratio. Likewise, the DTMD designed with resort to the second type of optimum objective functions can practically attain the same effectiveness as the TMD with equal total mass ratio. More importantly, in the robustness to the changes in the DFR, the DTMD is significantly better than the TMD, whereas in the robustness to the natural frequency tuning (NFT), measured by the

  3. Acceleration ground test program to verify GAS payload No. 559 structure/support avionics and experiment structural integrity

    NASA Technical Reports Server (NTRS)

    Cassanto, John M.; Cassanto, Valerie A.

    1988-01-01

    Acceleration ground tests were conducted on the Get Away Special (GAS) payload 559 to verify the structural integrity of the structure/support avionics and two of the planned three flight experiments. The ITA (Integrated Test Area) Standardized Experiment Module (ISEM) structure was modified to accommodate the experiments for payload 559. The ISEM avionics consisted of a heavy duty sliver zinc power supply, three orthogonal-mounted low range microgravity accelerometers, a tri-axis high range accelerometer, a solid state recorder/programmer sequencer, and pressure and temperature sensors. The tests were conducted using the Gravitational Plant Physiology Laboratory Centrifuge of the University City Science Center in Philadelphia, PA. The launch-powered flight steady state acceleration profile of the shuttle was simulated from lift-off through jettison of the External Tank (3.0 g's). Additional tests were conducted at twice the nominal powered flight acceleration levels (6 g's) and an over-test condition of four times the powered flight loads to 12.6 g's. The present test program has demonstrated the value of conducting ground tests to verify GAS payload experiment integrity and operation before flying on the shuttle.

  4. Permafrost thawing in organic Arctic soils accelerated by ground heat production

    NASA Astrophysics Data System (ADS)

    Hollesen, Jørgen; Matthiesen, Henning; Møller, Anders Bjørn; Elberling, Bo

    2015-06-01

    Decomposition of organic carbon from thawing permafrost soils and the resulting release of carbon to the atmosphere are considered to represent a potentially critical global-scale feedback on climate change. The accompanying heat production from microbial metabolism of organic material has been recognized as a potential positive-feedback mechanism that would enhance permafrost thawing and the release of carbon. This internal heat production is poorly understood, however, and the strength of this effect remains unclear. Here, we have quantified the variability of heat production in contrasting organic permafrost soils across Greenland and tested the hypothesis that these soils produce enough heat to reach a tipping point after which internal heat production can accelerate the decomposition processes. Results show that the impact of climate changes on natural organic soils can be accelerated by microbial heat production with crucial implications for the amounts of carbon being decomposed. The same is shown to be true for organic middens with the risk of losing unique evidence of early human presence in the Arctic.

  5. Atomic oxygen ground-based accelerated tests of spacecraft materials and structures for long-term LEO missions

    NASA Astrophysics Data System (ADS)

    Chernik, Vladimir; Novikov, Lev; Smirnova, Tatyana; Shumov, Andrey

    Spacecraft materials are degradated during long-term low earth orbit (LEO) flight. The Internation Space Station (ISS) is planed to be prolonged the term of action up to 20-25 years. To specify so long life one requires a validation of spacecraft material behaviour conservation for the period. The LEO environment includes atomic oxygen (AO) destructive incident flow. The appropriate AO fluence is proposed to be as high as 10E22-10E23 atom O/sq cm. The simulative ground-based test is evident to be acceptable if its duration is not too long usually under several hundreds of hours. In that case the rate of the test acceleration exceeds 100-200. One way to accelerate test is to increase oxygen particles energy. We test materials under oxygen plasma beam, formed by a magnetoplasmadynamic accelerator, with the oxygen particle energy of 20 -30 eV. In this way we determine an AO effective fluence by a kapton equivalent technique. The beam varies from LEO incident flow by energy, flux and rates of the oxygen dissociation / ionization/ excitation. To evaluate the test adequacy we measured and compared with LEO data erosion yields of a number of polymer materials, applied on spacecraft external surfaces. There were: polyimide (kapton), polyamide (nylon), polyethylene, polyvinyl fluoride (tedlar), polysteren, polymethyl methacrylate, epoxy, polyethylene terephthalate (mylar), graphite. Their relative erosion yields, measured and normalized by polyimide in this way, practically coincide with the data of flight experiments on the ISS. The results ground to use our plasma mode for accelerated tests of spacecraft material durability for long-term LEO flights. We tested quite a number of polymer-based materials and structures usable on ISS and another LEO spacecrafts. The effective AO fluencies ran up to 3,5 10E22 atom O/sq cm corresponding to the ISS flight duration about 20 years. We studied material behaviors like mass and thickness losses, erosion yield, surface morphology

  6. Ground Motion Prediction Models for Caucasus Region

    NASA Astrophysics Data System (ADS)

    Jorjiashvili, Nato; Godoladze, Tea; Tvaradze, Nino; Tumanova, Nino

    2016-04-01

    Ground motion prediction models (GMPMs) relate ground motion intensity measures to variables describing earthquake source, path, and site effects. Estimation of expected ground motion is a fundamental earthquake hazard assessment. The most commonly used parameter for attenuation relation is peak ground acceleration or spectral acceleration because this parameter gives useful information for Seismic Hazard Assessment. Since 2003 development of Georgian Digital Seismic Network has started. In this study new GMP models are obtained based on new data from Georgian seismic network and also from neighboring countries. Estimation of models is obtained by classical, statistical way, regression analysis. In this study site ground conditions are additionally considered because the same earthquake recorded at the same distance may cause different damage according to ground conditions. Empirical ground-motion prediction models (GMPMs) require adjustment to make them appropriate for site-specific scenarios. However, the process of making such adjustments remains a challenge. This work presents a holistic framework for the development of a peak ground acceleration (PGA) or spectral acceleration (SA) GMPE that is easily adjustable to different seismological conditions and does not suffer from the practical problems associated with adjustments in the response spectral domain.

  7. Estimation of ground motion parameters

    USGS Publications Warehouse

    Boore, David M.; Oliver, Adolph A., III; Page, Robert A.; Joyner, William B.

    1978-01-01

    Strong motion data from western North America for earthquakes of magnitude greater than 5 are examined to provide the basis for estimating peak acceleration, velocity, displacement, and duration as a function of distance for three magnitude classes. Data from the San Fernando earthquake are examined to assess the effects of associated structures and of geologic site conditions on peak recorded motions. Small but statistically significant differences are observed in peak values of horizontal acceleration, velocity, and displacement recorded on soil at the base of small structures compared with values recorded at the base of large structures. Values of peak horizontal acceleration recorded at soil sites in the San Fernando earthquake are not significantly different from the values recorded at rock sites, but values of peak horizontal velocity and displacement are significantly greater at soil sites than at rock sites. Three recently published relationships for predicting peak horizontal acceleration are compared and discussed. Considerations are reviewed relevant to ground motion predictions at close distances where there are insufficient recorded data points.

  8. Seismic design technology for breeder reactor structures. Volume 1. Special topics in earthquake ground motion

    SciTech Connect

    Reddy, D.P.

    1983-04-01

    This report is divided into twelve chapters: seismic hazard analysis procedures, statistical and probabilistic considerations, vertical ground motion characteristics, vertical ground response spectrum shapes, effects of inclined rock strata on site response, correlation of ground response spectra with intensity, intensity attenuation relationships, peak ground acceleration in the very mean field, statistical analysis of response spectral amplitudes, contributions of body and surface waves, evaluation of ground motion characteristics, and design earthquake motions. (DLC)

  9. Effect of additional optical pumping injection into the ground-state ensemble on the gain and the phase recovery acceleration of quantum-dot semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    Kim, Jungho

    2014-02-01

    The effect of additional optical pumping injection into the ground-state ensemble on the ultrafast gain and the phase recovery dynamics of electrically-driven quantum-dot semiconductor optical amplifiers is numerically investigated by solving 1088 coupled rate equations. The ultrafast gain and the phase recovery responses are calculated with respect to the additional optical pumping power. Increasing the additional optical pumping power can significantly accelerate the ultrafast phase recovery, which cannot be done by increasing the injection current density.

  10. First Ground-Based Infrared Solar Absorption Measurements of Free Tropospheric Methanol (CH3OH): Multidecade Infrared Time Series from Kitt Peak (31.9 deg N 111.6 deg W): Trend, Seasonal Cycle, and Comparison with Previous Measurements

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Mahieu, Emmanuel; Chiou, Linda; Herbin, Herve

    2009-01-01

    Atmospheric CH3OH (methanol) free tropospheric (2.09-14-km altitude) time series spanning 22 years has been analyzed on the basis of high-spectral resolution infrared solar absorption spectra of the strong vs band recorded from the U.S. National Solar Observatory on Kitt Peak (latitude 31.9degN, 111.6degW, 2.09-km altitude) with a 1-m Fourier transform spectrometer (FTS). The measurements span October 1981 to December 2003 and are the first long time series of CH3OH measurements obtained from the ground. The results were analyzed with SFIT2 version 3.93 and show a factor of three variations with season, a maximum at the beginning of July, a winter minimum, and no statistically significant long-term trend over the measurement time span.

  11. First Ground-Based Infrared Solar Absorption Measurements of Free Tropospheric Methanol (CH3OH): Multidecade Infrared Time Series from Kitt Peak (31.9 deg N 111.6 deg W): Trend, Seasonal Cycle, and Comparison with Previous Measurements

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Mahieu, Emmanuel; Chiou, Linda; Herbin, Herve

    2009-01-01

    Atmospheric CH3OH (methanol) free tropospheric (2.09-14-km altitude) time series spanning 22 years has been analyzed on the basis of high-spectral resolution infrared solar absorption spectra of the strong n8 band recorded from the U.S. National Solar Observatory on Kitt Peak (latitude 31.9degN, 111.6degW, 2.09-km altitude) with a 1-m Fourier transform spectrometer (FTS). The measurements span October 1981 to December 2003 and are the first long time series of CH3OH measurements obtained from the ground. The results were analyzed with SFIT2 version 3.93 and show a factor of three variations with season, a maximum at the beginning of July, a winter minimum, and no statistically significant long-term trend over the measurement time span.

  12. Estimation of ground motion parameters

    USGS Publications Warehouse

    Boore, David M.; Joyner, W.B.; Oliver, A.A.; Page, R.A.

    1978-01-01

    Strong motion data from western North America for earthquakes of magnitude greater than 5 are examined to provide the basis for estimating peak acceleration, velocity, displacement, and duration as a function of distance for three magnitude classes. A subset of the data (from the San Fernando earthquake) is used to assess the effects of structural size and of geologic site conditions on peak motions recorded at the base of structures. Small but statistically significant differences are observed in peak values of horizontal acceleration, velocity and displacement recorded on soil at the base of small structures compared with values recorded at the base of large structures. The peak acceleration tends to b3e less and the peak velocity and displacement tend to be greater on the average at the base of large structures than at the base of small structures. In the distance range used in the regression analysis (15-100 km) the values of peak horizontal acceleration recorded at soil sites in the San Fernando earthquake are not significantly different from the values recorded at rock sites, but values of peak horizontal velocity and displacement are significantly greater at soil sites than at rock sites. Some consideration is given to the prediction of ground motions at close distances where there are insufficient recorded data points. As might be expected from the lack of data, published relations for predicting peak horizontal acceleration give widely divergent estimates at close distances (three well known relations predict accelerations between 0.33 g to slightly over 1 g at a distance of 5 km from a magnitude 6.5 earthquake). After considering the physics of the faulting process, the few available data close to faults, and the modifying effects of surface topography, at the present time it would be difficult to accept estimates less than about 0.8 g, 110 cm/s, and 40 cm, respectively, for the mean values of peak acceleration, velocity, and displacement at rock sites

  13. A summary of ground motion effects at SLAC (Stanford Linear Accelerator Center) resulting from the Oct 17th 1989 earthquake

    SciTech Connect

    Ruland, R.E.

    1990-08-01

    Ground motions resulting from the October 17th 1989 (Loma Prieta) earthquake are described and can be correlated with some geologic features of the SLAC site. Recent deformations of the linac are also related to slow motions observed over the past 20 years. Measured characteristics of the earthquake are listed. Some effects on machine components and detectors are noted. 18 refs., 16 figs.

  14. Relativistic electron acceleration by compressional-mode ULF waves: Evidence from correlated Cluster, Los Alamos National Laboratory spacecraft, and ground-based magnetometer measurements

    NASA Astrophysics Data System (ADS)

    Tan, Lun C.; Shao, X.; Sharma, A. S.; Fung, Shing F.

    2011-07-01

    Simultaneous observations by Cluster and Los Alamos National Laboratory (LANL) spacecraft and Canadian Array for Real-Time Investigations of Magnetic Activity and International Monitor for Auroral Geomagnetic Effects magnetometer arrays during a sudden storm commencement on 25 September 2001 show evidence of relativistic electron acceleration by compressional-mode ULF waves. The waves are driven by the quasiperiodic solar wind dynamical pressure fluctuations that continuously buffet the magnetosphere for ˜3 h. The compressional-mode ULF waves are identified by comparing the power of magnetic field magnitude fluctuations with the total magnetic field power. The radial distribution and azimuthal propagation of both toroidal and poloidal-mode ULF waves are derived from ground-based magnetometer data. The energetic electron fluxes measured by LANL show modulation of low-energy electrons and acceleration of high-energy electrons by the compressional poloidal-mode electric field oscillations. The energy threshold of accelerated electrons at the geosynchronous orbit is ˜0.4 MeV, which is roughly consistent with drift-resonant interaction of magnetospheric electrons with compressional-mode ULF waves.

  15. Measurement, characterization, and prediction of strong ground motion

    USGS Publications Warehouse

    Joyner, William; Boore, David M.

    1988-01-01

    A number of predictive relationships derived from regression analysis of strong-motion data are available for horizontal peak acceleration, velocity, and response spectral values. Theoretical prediction of ground motion calls for stochastic source models because source heterogeneities control the amplitude of ground motion at most, if not all, frequencies of engineering interest. Theoretical methods have been developed for estimation of ground-motion parameters and simulation of ground-motion time series. These methods are particularly helpful for regions such, as eastern North America where strong-motion data are sparse. The authors survey the field, first reviewing developments in ground-motion measurement and data processing. The authors then consider the choice of parameters for characterizing strong ground motion and describe the wave-types involved in strong ground motion and the factors affecting ground-motion amplitudes. They conclude by describing methods for predicting ground motion.

  16. An Improved Approach for Nonstationary Strong Ground Motion Simulation

    NASA Astrophysics Data System (ADS)

    Li, Yanan; Wang, Guoxin

    2016-05-01

    A new stochastic ground motion model for generating a suite of ground motion time history with both temporal and frequency nonstationarities for specified earthquake and site characteristics is proposed based on the wavelet method. This new model is defined in terms of 6 key parameters that characterize the duration, evolving intensity, predominant frequency, bandwidth and frequency variation of the ground acceleration process. All parameters, except for peak ground acceleration (PGA), are identified manually from a database of 2444 recorded horizontal accelerations. The two-stage regression analysis method is used to investigate the inter- and intra-event residuals. For any given earthquake and site characteristics in terms of the fault mechanism, moment magnitude, Joyner and Boore distance and site shear-wave velocity, sets of the model parameters are generated and used, in turn, by the stochastic model to generate strong ground motion accelerograms, which can capture and properly embody the primary features of real strong ground motions, including the duration, evolving intensity, spectral content, frequency variation and peak values. In addition, it is shown that the characteristics of the simulated and observed response spectra are similar, and the amplitude of the simulated response spectra are in line with the predicted values from the published seismic ground motion prediction equations (SGMPE) after a systematic comparison. The proposed method can be used to estimate the strong ground motions as inputs for structural seismic dynamic analysis in engineering practice in conjunction with or instead of recorded ground motions.

  17. Accelerated Ground Deformation of the Yellowstone Caldera, 2004-2008: Update from GPS and InSAR Observations

    NASA Astrophysics Data System (ADS)

    Chang, W.; Smith, R. B.; Wicks, C.; Puskas, C.

    2008-12-01

    The Yellowstone volcanic system is characterized by decadal-scale episodes of ground deformation, extensive seismicity, extraordinarily high heat flow exceeding ~2,000 mW/m2, and widespread hydrothermal activity. In mid-2004, ground motion of the 640,000 year-old, 40-km-wide by 60-km-long Yellowstone caldera unexpectedly changed from subsidence to uplift at rates of up to 7 cm/yr based upon GPS and InSAR measurements. This pronounced uplift, three to four times faster than earlier historic deformation episodes, was also accompanied by a subsidence of up to 4 cm/yr across the northwest caldera rim near the Norris Geyser Basin. Source modeling of the deformation data indicated magmatic injection of a volcanic sill 10 km beneath the caldera that coincides with the top of a tomographically imaged magma body. As an update to the initial observations it shows that the uplift rate has diminished to ~5 cm/yr since mid-2006 and continued to fall 2008, whereas the Norris subsidence episode ceased near the middle of 2006. To better assess these spatial and temporal variations of the deformation field, we conducted a GPS survey of 17 sites, originally observed beginning in 1987, in the summer of 2008 to supplement data from the 13 permanent GPS stations of the Yellowstone GPS network. Updated 3D source modeling based on these data and 2008 InSAR observations provides key information on the temporal variations and volcanic properties of this important episode of Yellowstone deformation.

  18. SISMA (Site of Italian Strong Motion Accelerograms): a Web-Database of Ground Motion Recordings for Engineering Applications

    SciTech Connect

    Scasserra, Giuseppe; Lanzo, Giuseppe; D'Elia, Beniamino; Stewart, Jonathan P.

    2008-07-08

    The paper describes a new website called SISMA, i.e. Site of Italian Strong Motion Accelerograms, which is an Internet portal intended to provide natural records for use in engineering applications for dynamic analyses of structural and geotechnical systems. SISMA contains 247 three-component corrected motions recorded at 101 stations from 89 earthquakes that occurred in Italy in the period 1972-2002. The database of strong motion accelerograms was developed in the framework of a joint project between Sapienza University of Rome and University of California at Los Angeles (USA) and is described elsewhere. Acceleration histories and pseudo-acceleration response spectra (5% damping) are available for download from the website. Recordings can be located using simple search parameters related to seismic source and the recording station (e.g., magnitude, V{sub s30}, etc) as well as ground motion characteristics (e.g. peak ground acceleration, peak ground velocity, peak ground displacement, Arias intensity, etc.)

  19. Modeling of strong ground motion during the 1992 Cairo earthquake in the urban area northern Greater of Cairo, Egypt

    NASA Astrophysics Data System (ADS)

    Omar, Khaled; Attia, Mohsen; Fergany, El Sayed; Hassoup, Awad; Elkhashab, Hussein

    2013-06-01

    The 1992 Cairo earthquake originated from Dahshour seismic zone at an epicentral distance of about 25 km southwest of Cairo. Regardless of its relatively moderate magnitude (Mb = 5.8), it caused extensive property damage besides injuries and loss of lives. The significant damage of this earthquake was probably associated with amplification of seismic waves due to local site effects. Liquefaction was observed at many sites near the epicenter. There are no records of strong ground motion at the damaged area during this earthquake. The main shock was recorded only by the local Kattamya station (KEG) constructed in limestone rock site at about 46-48 km east of Cairo. In the present work, the strong ground motion during 1992 Cairo earthquake was analyzed and the possible causes of damage and structural failure were discussed. The study area is located at the southern part of Cairo city, holding heavy population and many public structures and strategic buildings. The ground motion parameters in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and pseudo-spectral acceleration (PSA) were estimated for each site in the study area and in the KEG site. The site-dependent spectral models together with the stochastic technique were applied for this purpose, using the Fourier amplitude spectrum (FAS) source scaling, attenuation model, and the site amplification functions. The peak ground acceleration of the studied area, comprising 89 sites in northern great of Cairo (Qalyoub city) was calculated. The calculated peak ground acceleration values indicate the sites of high values of peak ground acceleration which are also characterized by high ground motion amplification factors. The ground motion, which is presented in this study, is highly amplified by the soil layer covering the area. Otherwise, the surface layer must be totally removed before construction of the buildings to avoid its large amplification to the ground motion.

  20. Portable peak flow meters.

    PubMed

    McNaughton, J P

    1997-02-01

    There are several portable peak flow meters available. These instruments vary in construction and performance. Guidelines are recommended for minimum performance and testing of portable peak flow meters, with the aim of establishing a procedure for standardizing all peak flow meters. Future studies to clarify the usefulness of mechanical test apparatus and clinical trials of peak flow meters are also recommended. PMID:9098706

  1. Impact Accelerations of Barefoot and Shod Running.

    PubMed

    Thompson, M; Seegmiller, J; McGowan, C P

    2016-05-01

    During the ground contact phase of running, the body's mass is rapidly decelerated resulting in forces that propagate through the musculoskeletal system. The repetitive attenuation of these impact forces is thought to contribute to overuse injuries. Modern running shoes are designed to reduce impact forces, with the goal to minimize running related overuse injuries. Additionally, the fore/mid foot strike pattern that is adopted by most individuals when running barefoot may reduce impact force transmission. The aim of the present study was to compare the effects of the barefoot running form (fore/mid foot strike & decreased stride length) and running shoes on running kinetics and impact accelerations. 10 healthy, physically active, heel strike runners ran in 3 conditions: shod, barefoot and barefoot while heel striking, during which 3-dimensional motion analysis, ground reaction force and accelerometer data were collected. Shod running was associated with increased ground reaction force and impact peak magnitudes, but decreased impact accelerations, suggesting that the midsole of running shoes helps to attenuate impact forces. Barefoot running exhibited a similar decrease in impact accelerations, as well as decreased impact peak magnitude, which appears to be due to a decrease in stride length and/or a more plantarflexed position at ground contact. PMID:26837933

  2. Empirical prediction of strong ground motion

    USGS Publications Warehouse

    Boore, David M.; Joyner, William B.

    1993-01-01

    In 1982, we published equations for the prediction of various measures of ground motion as a function of earthquake magnitude, distance from the earthquake rupture, and site geology. Many more strong-motion recordings have been obtained since we published our equations. The predictions of the ground motions from our published equations are in reasonable agreement with the peak accelerations from the new data. The increased number of data, however, allow us to refine our predictions for some regions of magnitude and distance space, and perhaps for other variables.

  3. Peak flow meter (image)

    MedlinePlus

    A peak flow meter is commonly used by a person with asthma to measure the amount of air that can be ... become narrow or blocked due to asthma, peak flow values will drop because the person cannot blow ...

  4. Development of Maximum Considered Earthquake Ground Motion Maps

    USGS Publications Warehouse

    Leyendecker, E.V.; Hunt, R.J.; Frankel, A.D.; Rukstales, K.S.

    2000-01-01

    The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings use a design procedure that is based on spectral response acceleration rather than the traditional peak ground acceleration, peak ground velocity, or zone factors. The spectral response accelerations are obtained from maps prepared following the recommendations of the Building Seismic Safety Council's (BSSC) Seismic Design Procedures Group (SDPG). The SDPG-recommended maps, the Maximum Considered Earthquake (MCE) Ground Motion Maps, are based on the U.S. Geological Survey (USGS) probabilistic hazard maps with additional modifications incorporating deterministic ground motions in selected areas and the application of engineering judgement. The MCE ground motion maps included with the 1997 NEHRP Provisions also serve as the basis for the ground motion maps used in the seismic design portions of the 2000 International Building Code and the 2000 International Residential Code. Additionally the design maps prepared for the 1997 NEHRP Provisions, combined with selected USGS probabilistic maps, are used with the 1997 NEHRP Guidelines for the Seismic Rehabilitation of Buildings.

  5. Monitoring for volcano-hydrothermal activity using continuous gravity and local ground acceleration measurements: New deployments at Inferno Crater, Waimangu and White Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Jolly, Arthur; Fournier, Nico; Cole-Baker, Jeremy; Miller, Craig

    2010-05-01

    Volcanoes with crater lakes are often characterised by shallow hydrothermal systems which display cyclic behaviour (temperature, lake level, chemistry, etc.) and shallow seismic tremor. Present monitoring programmes in New Zealand include routine collection of these observables, but the associated shallow sub-surface processes are still inadequately modelled and poorly understood. Models would be better constrained with the incorporation of additional geophysical parameters. To this end, we have established a new test programme to continuously monitor for micro-gravity variations at New Zealand volcanoes. We utilise a Micro-g-LaCoste gPhone relative gravity meter having 1 Hz sample rate and a measurement precision of 1 microgal to test the viability of gravity monitoring for volcano-hydrothermal systems. We have initially tested the new sensor in a short term deployment (~2 months) at Inferno Crater, Waimangu, New Zealand. Inferno shows dramatic variations in crater lake level (> 7 m range), temperature (>40o C range) and hydrothermally derived tremor, all over a period of ~5 weeks. The amplitude and period of these observables are ideal for testing gravity variations associated with a cycling hydrothermal system because several cycles can be obtained in a relatively short campaign. We have deployed the gravity sensor into a buried vault having a stable concrete base to minimise local environmental influences. This vault is located ~20 meters from Inferno Lake edge (at high stand) and offers sufficient noise reduction to measure the gravitational effects associated with lake level changes. We will show results for the new gravity meter including raw relative gravity measurements and first order corrections (earth-tide, ocean loading, sensor level, temperature, and barometric pressure) to obtain both residual gravity and overprinted local ground accelerations (earthquakes and local tremor). To examine the effects of local ground vibrations on the gravity meter, we

  6. Strong Ground Motion Estimation During the Kutch, India Earthquake

    NASA Astrophysics Data System (ADS)

    Iyengar, R. N.; Kanth, S. T. G. Raghu

    2006-01-01

    In the absence of strong motion records, ground motion during the 26th January, 2001 Kutch, India earthquake, has been estimated by analytical methods. A contour map of peak ground acceleration (PGA) values in the near source region is provided. These results are validated by comparing them with spectral response recorder data and field observations. It is found that very near the epicenter, PGA would have exceeded 0.6 g. A set of three aftershock records have been used as empirical Green's functions to simulate ground acceleration time history and 5% damped response spectrum at Bhuj City. It is found that at Bhuj, PGA would have been 0.31 g 0.37 g. It is demonstrated that source mechanism models can be effectively used to understand spatial variability of large-scale ground movements near urban areas due to the rupture of active faults.

  7. Peak Experience Project

    ERIC Educational Resources Information Center

    Scott, Daniel G.; Evans, Jessica

    2010-01-01

    This paper emerges from the continued analysis of data collected in a series of international studies concerning Childhood Peak Experiences (CPEs) based on developments in understanding peak experiences in Maslow's hierarchy of needs initiated by Dr Edward Hoffman. Bridging from the series of studies, Canadian researchers explore collected…

  8. 2009 Observations of X-rays at South Baldy Peak

    NASA Astrophysics Data System (ADS)

    Lundberg, J.; Millan, R.

    2009-12-01

    Observations of x-rays were made using two scintillator detectors (a 3x3 in. NaI crystal and a 1.5x1.5 in. LaBr(Ce) crystal) atop South Baldy Peak, New Mexico from July until September in an attempt to observe x-ray emissions from lightning strikes. It has been observed previously that accelerated electrons in lightning produce Bremsstrahlung that can be seen with ground detectors. The output of the two detectors was digitized without the use of pre-amplification to preserve pulse shapes during high count rate events. Being presented is data from these observations as well as comparisons of analysis techniques that can be used to decompose simple output pulses from scintillator detectors.

  9. Vibration control in accelerators

    SciTech Connect

    Montag, C.

    2011-01-01

    In the vast majority of accelerator applications, ground vibration amplitudes are well below tolerable magnet jitter amplitudes. In these cases, it is necessary and sufficient to design a rigid magnet support structure that does not amplify ground vibration. Since accelerator beam lines are typically installed at an elevation of 1-2m above ground level, special care has to be taken in order to avoid designing a support structure that acts like an inverted pendulum with a low resonance frequency, resulting in untolerable lateral vibration amplitudes of the accelerator components when excited by either ambient ground motion or vibration sources within the accelerator itself, such as cooling water pumps or helium flow in superconducting magnets. In cases where ground motion amplitudes already exceed the required jiter tolerances, for instance in future linear colliders, passive vibration damping or active stabilization may be considered.

  10. Correlated peak relative light intensity and peak current in triggered lightning subsequent return strokes

    NASA Technical Reports Server (NTRS)

    Idone, V. P.; Orville, R. E.

    1985-01-01

    The correlation between peak relative light intensity L(R) and stroke peak current I(R) is examined for 39 subsequent return strokes in two triggered lightning flashes. One flash contained 19 strokes and the other 20 strokes for which direct measurements were available of the return stroke peak current at ground. Peak currents ranged from 1.6 to 21 kA. The measurements of peak relative light intensity were obtained from photographic streak recordings using calibrated film and microsecond resolution. Correlations, significant at better than the 0.1 percent level, were found for several functional relationships. Although a relation between L(R) and I(R) is evident in these data, none of the analytical relations considered is clearly favored. The correlation between L(R) and the maximum rate of current rise is also examined, but less correlation than between L(R) and I(R) is found. In addition, the peak relative intensity near ground is evaluated for 22 dart leaders, and a mean ratio of peak dart leader to peak return stroke relative light intensity was found to be 0.1 with a range of 0.02-0.23. Using two different methods, the peak current near ground in these dart leaders is estimated to range from 0.1 to 6 kA.

  11. Peak power ratio generator

    DOEpatents

    Moyer, R.D.

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  12. Peak power ratio generator

    DOEpatents

    Moyer, Robert D.

    1985-01-01

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  13. Multiscale peak alignment for chromatographic datasets.

    PubMed

    Zhang, Zhi-Min; Liang, Yi-Zeng; Lu, Hong-Mei; Tan, Bin-Bin; Xu, Xiao-Na; Ferro, Miguel

    2012-02-01

    Chromatography has been extensively applied in many fields, such as metabolomics and quality control of herbal medicines. Preprocessing, especially peak alignment, is a time-consuming task prior to the extraction of useful information from the datasets by chemometrics and statistics. To accurately and rapidly align shift peaks among one-dimensional chromatograms, multiscale peak alignment (MSPA) is presented in this research. Peaks of each chromatogram were detected based on continuous wavelet transform (CWT) and aligned against a reference chromatogram from large to small scale gradually, and the aligning procedure is accelerated by fast Fourier transform cross correlation. The presented method was compared with two widely used alignment methods on chromatographic dataset, which demonstrates that MSPA can preserve the shapes of peaks and has an excellent speed during alignment. Furthermore, MSPA method is robust and not sensitive to noise and baseline. MSPA was implemented and is available at http://code.google.com/p/mspa. PMID:22222564

  14. Peak Oil, Peak Coal and Climate Change

    NASA Astrophysics Data System (ADS)

    Murray, J. W.

    2009-05-01

    Research on future climate change is driven by the family of scenarios developed for the IPCC assessment reports. These scenarios create projections of future energy demand using different story lines consisting of government policies, population projections, and economic models. None of these scenarios consider resources to be limiting. In many of these scenarios oil production is still increasing to 2100. Resource limitation (in a geological sense) is a real possibility that needs more serious consideration. The concept of 'Peak Oil' has been discussed since M. King Hubbert proposed in 1956 that US oil production would peak in 1970. His prediction was accurate. This concept is about production rate not reserves. For many oil producing countries (and all OPEC countries) reserves are closely guarded state secrets and appear to be overstated. Claims that the reserves are 'proven' cannot be independently verified. Hubbert's Linearization Model can be used to predict when half the ultimate oil will be produced and what the ultimate total cumulative production (Qt) will be. US oil production can be used as an example. This conceptual model shows that 90% of the ultimate US oil production (Qt = 225 billion barrels) will have occurred by 2011. This approach can then be used to suggest that total global production will be about 2200 billion barrels and that the half way point will be reached by about 2010. This amount is about 5 to 7 times less than assumed by the IPCC scenarios. The decline of Non-OPEC oil production appears to have started in 2004. Of the OPEC countries, only Saudi Arabia may have spare capacity, but even that is uncertain, because of lack of data transparency. The concept of 'Peak Coal' is more controversial, but even the US National Academy Report in 2007 concluded only a small fraction of previously estimated reserves in the US are actually minable reserves and that US reserves should be reassessed using modern methods. British coal production can be

  15. Make peak flow a habit!

    MedlinePlus

    Asthma - make peak flow a habit; Reactive airway disease - peak flow; Bronchial asthma - peak flow ... your airways are narrowed and blocked due to asthma, your peak flow values drop. You can check ...

  16. Hale Central Peak

    NASA Technical Reports Server (NTRS)

    2004-01-01

    19 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some of the mountains that make up the central peak region of Hale Crater, located near 35.8oS, 36.5oW. Dark, smooth-surfaced sand dunes are seen to be climbing up the mountainous slopes. The central peak of a crater consists of rock brought up during the impact from below the crater floor. This autumn image is illuminated from the upper left and covers an area approximately 3 km (1.9 mi) across.

  17. Impact Crater with Peak

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 14 June 2002) The Science This THEMIS visible image shows a classic example of a martian impact crater with a central peak. Central peaks are common in large, fresh craters on both Mars and the Moon. This peak formed during the extremely high-energy impact cratering event. In many martian craters the central peak has been either eroded or buried by later sedimentary processes, so the presence of a peak in this crater indicates that the crater is relatively young and has experienced little degradation. Observations of large craters on the Earth and the Moon, as well as computer modeling of the impact process, show that the central peak contains material brought from deep beneath the surface. The material exposed in these peaks will provide an excellent opportunity to study the composition of the martian interior using THEMIS multi-spectral infrared observations. The ejecta material around the crater can is well preserved, again indicating relatively little modification of this landform since its initial creation. The inner walls of this approximately 18 km diameter crater show complex slumping that likely occurred during the impact event. Since that time there has been some downslope movement of material to form the small chutes and gullies that can be seen on the inner crater wall. Small (50-100 m) mega-ripples composed of mobile material can be seen on the floor of the crater. Much of this material may have come from the walls of the crater itself, or may have been blown into the crater by the wind. The Story When a meteor smacked into the surface of Mars with extremely high energy, pow! Not only did it punch an 11-mile-wide crater in the smoother terrain, it created a central peak in the middle of the crater. This peak forms kind of on the 'rebound.' You can see this same effect if you drop a single drop of milk into a glass of milk. With craters, in the heat and fury of the impact, some of the land material can even liquefy. Central peaks like the one

  18. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  19. Using the FLUKA Monte Carlo Code to Simulate the Interactions of Ionizing Radiation with Matter to Assist and Aid Our Understanding of Ground Based Accelerator Testing, Space Hardware Design, and Secondary Space Radiation Environments

    NASA Technical Reports Server (NTRS)

    Reddell, Brandon

    2015-01-01

    Designing hardware to operate in the space radiation environment is a very difficult and costly activity. Ground based particle accelerators can be used to test for exposure to the radiation environment, one species at a time, however, the actual space environment cannot be duplicated because of the range of energies and isotropic nature of space radiation. The FLUKA Monte Carlo code is an integrated physics package based at CERN that has been under development for the last 40+ years and includes the most up-to-date fundamental physics theory and particle physics data. This work presents an overview of FLUKA and how it has been used in conjunction with ground based radiation testing for NASA and improve our understanding of secondary particle environments resulting from the interaction of space radiation with matter.

  20. PEAK READING VOLTMETER

    DOEpatents

    Dyer, A.L.

    1958-07-29

    An improvement in peak reading voltmeters is described, which provides for storing an electrical charge representative of the magnitude of a transient voltage pulse and thereafter measuring the stored charge, drawing oniy negligible energy from the storage element. The incoming voltage is rectified and stored in a condenser. The voltage of the capacitor is applied across a piezoelectric crystal between two parallel plates. Amy change in the voltage of the capacitor is reflected in a change in the dielectric constant of the crystal and the capacitance between a second pair of plates affixed to the crystal is altered. The latter capacitor forms part of the frequency determlning circuit of an oscillator and means is provided for indicating the frequency deviation which is a measure of the peak voltage applied to the voltmeter.

  1. INDIAN PEAKS WILDERNESS, COLORADO.

    USGS Publications Warehouse

    Pearson, Robert C.; Speltz, Charles N.

    1984-01-01

    The Indian Peaks Wilderness northwest of Denver is partly within the Colorado Mineral Belt, and the southeast part of it contains all the geologic characteristics associated with the several nearby mining districts. Two deposits have demonstrated mineral resources, one of copper and the other of uranium; both are surrounded by areas with probable potential. Two other areas have probable resource potential for copper, gold, and possibly molydenum. Detailed gravity and magnetic studies in the southeast part of the Indian Peaks Wilderness might detect in the subsurface igneous bodies that may be mineralized. Physical exploration such as drilling would be necessary to determine more precisely the copper resources at the Roaring Fork locality and uranium resources at Wheeler Basin.

  2. Peak of Desire

    PubMed Central

    Huang, Julie Y.; Bargh, John A.

    2008-01-01

    In three studies, we explore the existence of an evolved sensitivity to the peak as consistent with the evolutionary origins of many of our basic preferences. Activating the evolved motive of mating activates related adaptive mechanisms, including a general sensitivity to cues of growth and decay associated with determining mate value in human courtship. We establish that priming the mating goal also activates as well an evaluative bias that influences how people evaluate cues of growth. Specifically, living kinds that are immature or past their prime are devalued, whereas living kinds at their peak become increasingly valued. Study 1 establishes this goal-driven effect for human stimuli indirectly related to the mating goal. Studies 2 and 3 establish that the evaluative bias produced by the active mating goal extends to living kinds but not artifacts. PMID:18578847

  3. PEAK LIMITING AMPLIFIER

    DOEpatents

    Goldsworthy, W.W.; Robinson, J.B.

    1959-03-31

    A peak voltage amplitude limiting system adapted for use with a cascade type amplifier is described. In its detailed aspects, the invention includes an amplifier having at least a first triode tube and a second triode tube, the cathode of the second tube being connected to the anode of the first tube. A peak limiter triode tube has its control grid coupled to thc anode of the second tube and its anode connected to the cathode of the second tube. The operation of the limiter is controlled by a bias voltage source connected to the control grid of the limiter tube and the output of the system is taken from the anode of the second tube.

  4. DIAMOND PEAK WILDERNESS, OREGON.

    USGS Publications Warehouse

    Sherrod, David R.; Moyle, Phillip R.

    1984-01-01

    No metallic mineral resources were identified during a mineral survey of the Diamond Peak Wilderness in Oregon. Cinder cones within the wilderness contain substantial cinder resources, but similar deposits that are more accessible occur outside the wilderness. The area could have geothermal resources, but available data are insufficient to evaluate their potential. Several deep holes could be drilled in areas of the High Cascades outside the wilderness, from which extrapolations of the geothermal potential of the several Cascade wilderness could be made.

  5. Kitt Peak speckle camera

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Mcalister, H. A.; Robinson, W. G.

    1979-01-01

    The speckle camera in regular use at Kitt Peak National Observatory since 1974 is described in detail. The design of the atmospheric dispersion compensation prisms, the use of film as a recording medium, the accuracy of double star measurements, and the next generation speckle camera are discussed. Photographs of double star speckle patterns with separations from 1.4 sec of arc to 4.7 sec of arc are shown to illustrate the quality of image formation with this camera, the effects of seeing on the patterns, and to illustrate the isoplanatic patch of the atmosphere.

  6. Influence of surface-normal ground acceleration on the initiation of the Jih-Feng-Erh-Shan landslide during the 1999 Chi-Chi, Taiwan, earthquake

    USGS Publications Warehouse

    Huang, C.-C.; Lee, Y.-H.; Liu, Huaibao P.; Keefer, D.K.; Jibson, R.W.

    2001-01-01

    The 1999 Chi-Chi, Taiwan, earthquake triggered numerous landslides throughout a large area in the Central Range, to the east, southeast, and south of the fault rupture. Among them are two large rock avalanches, at Tsaoling and at Jih-Feng-Erh-Shan. At Jih-Feng-Erh-Shan, the entire thickness (30-50 m) of the Miocene Changhukeng Shale over an area of 1 km2 slid down its bedding plane for a distance of about 1 km. Initial movement of the landslide was nearly purely translational. We investigate the effect of surface-normal acceleration on the initiation of the Jih-Feng-Erh-Shan landslide using a block slide model. We show that this acceleration, currently not considered by dynamic slope-stability analysis methods, significantly influences the initiation of the landslide.

  7. Stride Leg Ground Reaction Forces Predict Throwing Velocity in Adult Recreational Baseball Pitchers.

    PubMed

    McNally, Michael P; Borstad, John D; Oñate, James A; Chaudhari, Ajit M W

    2015-10-01

    Ground reaction forces produced during baseball pitching have a significant impact in the development of ball velocity. However, the measurement of only one leg and small sample sizes in these studies curb the understanding of ground reaction forces as they relate to pitching. This study aimed to further clarify the role ground reaction forces play in developing pitching velocity. Eighteen former competitive baseball players with previous high school or collegiate pitching experience threw 15 fastballs from a pitcher's mound instrumented to measure ground reaction forces under both the drive and stride legs. Peak ground reaction forces were recorded during each phase of the pitching cycle, between peak knee height and ball release, in the medial/lateral, anterior/posterior, and vertical directions, and the peak resultant ground reaction force. Stride leg ground reaction forces during the arm-cocking and arm-acceleration phases were strongly correlated with ball velocity (r2 = 0.45-0.61), whereas drive leg ground reaction forces showed no significant correlations. Stepwise linear regression analysis found that peak stride leg ground reaction force during the arm-cocking phase was the best predictor of ball velocity (r2 = 0.61) among drive and stride leg ground reaction forces. This study demonstrates the importance of ground reaction force development in pitching, with stride leg forces being strongly predictive of ball velocity. Further research is needed to further clarify the role of ground reaction forces in pitching and to develop training programs designed to improve upper extremity mechanics and pitching performance through effective force development. PMID:26402471

  8. Exploring the mechanical basis for acceleration: pelvic limb locomotor function during accelerations in racing greyhounds (Canis familiaris).

    PubMed

    Williams, S B; Usherwood, J R; Jespers, K; Channon, A J; Wilson, A M

    2009-02-01

    Animals in their natural environments are confronted with a regular need to perform rapid accelerations (for example when escaping from predators or chasing prey). Such acceleration requires net positive mechanical work to be performed on the centre of mass by skeletal muscle. Here we determined how pelvic limb joints contribute to the mechanical work and power that are required for acceleration in galloping quadrupeds. In addition, we considered what, if any, biomechanical strategies exist to enable effective acceleration to be achieved. Simultaneous kinematic and kinetic data were collected for racing greyhounds undergoing a range of low to high accelerations. From these data, joint moments and joint powers were calculated for individual hindlimb joints. In addition, the mean effective mechanical advantage (EMA) of the limb and the ;gear ratio' of each joint throughout stance were calculated. Greatest increases in joint work and power with acceleration appeared at the hip and hock joints, particularly in the lead limb. Largest increases in absolute positive joint work occurred at the hip, consistent with the hypothesis that quadrupeds power locomotion by torque about the hip. In addition, hindlimb EMA decreased substantially with increased acceleration - a potential strategy to increase stance time and thus ground impulses for a given peak force. This mechanism may also increase the mechanical advantage for applying the horizontal forces necessary for acceleration. PMID:19181903

  9. Angular velocities, angular accelerations, and coriolis accelerations

    NASA Technical Reports Server (NTRS)

    Graybiel, A.

    1975-01-01

    Weightlessness, rotating environment, and mathematical analysis of Coriolis acceleration is described for man's biological effective force environments. Effects on the vestibular system are summarized, including the end organs, functional neurology, and input-output relations. Ground-based studies in preparation for space missions are examined, including functional tests, provocative tests, adaptive capacity tests, simulation studies, and antimotion sickness.

  10. Characteristics of the Strong Ground Motions from the 23 October 2011 Van earthquake, Turkey

    NASA Astrophysics Data System (ADS)

    Akinci, A.; Antonioli, A.

    2012-12-01

    The recent 23 October 2011 Mw 7.1 Van Earthquake occurred at 13:41 local time in Eastern Turkey with an epicenter at 43.36oE, 38.76oN (KOERI) caused severe damage in the epicenter area. Intenseve aftershocks followed, activating the several previously unknown small scale faults around the main fault rupture. Twenty-two accelerometric stations belonging to the National Strong Ground Motion Network (operated by the Earthquake Department of the Disaster and Emergency Management Presidency, AFAD) and eleven accelerometric stations of the Iranian Strong Motion Network (ISMN) recorded the main shock. In this study a great effort has been directed towards understanding the characteristics of ground motion associated with the Van Lake seismic sequences. In this respect we study the features of the strong ground motion recordings obtained during the main shock by means of the spatial variations of the peak ground accelerations and peak ground velocities, and the spectral accelerations (5% of critical damping) together with the site amplifications. High frequency ground motion stochastic simulations are performed in the near-fault area and compared with the empirical Ground Motion Prediction Equations (GMPEs). Finally, regarding the October-November Van earthquake sequence, a static analysis of the Coulomb Failure Function variation is carried out adopting the slip distributions retrieved by USGS (Hayes, 2011).

  11. GPU Acceleration of the Locally Selfconsistent Multiple Scattering Code for First Principles Calculation of the Ground State and Statistical Physics of Materials

    SciTech Connect

    Eisenbach, Markus; Larkin, Jeff; Lutjens, Justin; Rennich, Steven; Rogers, James H

    2016-01-01

    The Locally Self-consistent Multiple Scattering (LSMS) code solves the first principles Density Functional theory Kohn-Sham equation for a wide range of materials with a special focus on metals, alloys and metallic nano-structures. It has traditionally exhibited near perfect scalability on massively parallel high performance computer architectures. We present our efforts to exploit GPUs to accelerate the LSMS code to enable first principles calculations of O(100,000) atoms and statistical physics sampling of finite temperature properties. Using the Cray XK7 system Titan at the Oak Ridge Leadership Computing Facility we achieve a sustained performance of 14.5PFlop/s and a speedup of 8.6 compared to the CPU only code.

  12. Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Sidorin, Anatoly

    2010-01-01

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  13. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  14. Attention's Accelerator.

    PubMed

    Reinhart, Robert M G; McClenahan, Laura J; Woodman, Geoffrey F

    2016-06-01

    How do people get attention to operate at peak efficiency in high-pressure situations? We tested the hypothesis that the general mechanism that allows this is the maintenance of multiple target representations in working and long-term memory. We recorded subjects' event-related potentials (ERPs) indexing the working memory and long-term memory representations used to control attention while performing visual search. We found that subjects used both types of memories to control attention when they performed the visual search task with a large reward at stake, or when they were cued to respond as fast as possible. However, under normal circumstances, one type of target memory was sufficient for slower task performance. The use of multiple types of memory representations appears to provide converging top-down control of attention, allowing people to step on the attentional accelerator in a variety of high-pressure situations. PMID:27056975

  15. Accelerating Rates of Discontinuous Permafrost Thaw Associated with Ground Surface Morphology and Changing Vegetation Structures Determined from Multi-Temporal LIDAR Data

    NASA Astrophysics Data System (ADS)

    Chasmer, L.; Hopkinson, C.

    2015-12-01

    Rates of permafrost thaw within the discontinuous permafrost zone are expected to accelerate with permafrost fragmentation. However quantification of drivers of permafrost change remain elusive due to the non-linearity of feedbacks in space and time. Given the extent of permafrost in Canada, there is significant interest in the mechanisms associated with land cover change as climate change and disturbance intensifies.We quantify the variability of rates of thaw associated with structural characteristics of the land surface within a discontinuous permafrost watershed in the NWT, Canada. Results are compared to an isolated permafrost watershed in Alberta, which may exemplify the northern discontinuous landscape in ~350 years. Three airborne Light Detection And Ranging (LiDAR) datasets have been collected in 2008, 2011 and 2015, coincident with digital photogrammetry (2008), thermal infrared (2011) and bathymetry (2015) within both watersheds. Rates of change of land elevation associated with permafrost thaw within plateaus and peatlands are quantified using non-linear spatial regression, and compared with topographic and vegetation derivatives. Results indicate that increasing fragmentation of discontinuous permafrost plateaus results in exponential thaw. Rates of thaw become linear with decreasing complexity. Accelerating thaw is related to substantial Picea mariana mortality (up to 45%), increased gap fraction within 1-2 m of plateau edges, and shrub succession (average growth ~0.2 m yr—1) at the 0-2m boundary within the 7-year period. Thaw rate in parts is also complicated by understory succession within the area of local convexity between the plateau and slope edge and linear thaw pathways. Greatest rates of thaw and vegetation mortality (~30-50%) are found on plateaus with populous tremuloides. In the central boreal watershed, vegetation succession at peatland margins is associated with increased drying and changes to runoff trends over the last 40 years

  16. Make peak flow a habit!

    MedlinePlus

    Checking your peak flow is one of the best ways to control your asthma and to keep it from getting worse. Asthma attacks ... Most times, they build slowly. Checking your peak flow can tell you if an attack is coming, ...

  17. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  18. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  19. Decoupling approximation design using the peak to peak gain

    NASA Astrophysics Data System (ADS)

    Sultan, Cornel

    2013-04-01

    Linear system design for accurate decoupling approximation is examined using the peak to peak gain of the error system. The design problem consists in finding values of system parameters to ensure that this gain is small. For this purpose a computationally inexpensive upper bound on the peak to peak gain, namely the star norm, is minimized using a stochastic method. Examples of the methodology's application to tensegrity structures design are presented. Connections between the accuracy of the approximation, the damping matrix, and the natural frequencies of the system are examined, as well as decoupling in the context of open and closed loop control.

  20. Ground motion modeling of Hayward fault scenario earthquakes II:Simulation of long-period and broadband ground motions

    SciTech Connect

    Aagaard, B T; Graves, R W; Rodgers, A; Brocher, T M; Simpson, R W; Dreger, D; Petersson, N A; Larsen, S C; Ma, S; Jachens, R C

    2009-11-04

    We simulate long-period (T > 1.0-2.0 s) and broadband (T > 0.1 s) ground motions for 39 scenarios earthquakes (Mw 6.7-7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area with about 50% of the urban area experiencing MMI VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland and 2007 Mw 4.5 Alum Rock earthquakes show that the USGS Bay Area Velocity Model version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground motions exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground motions display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground motions are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-motion prediction equations. We attribute at least some of this difference to the relatively narrow width of the Hayward fault ruptures. The simulations suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by including a dependence on the rupture speed and increasing the areal extent of rupture directivity with period. The simulations also indicate that the NGA relations may under-predict amplification in shallow sedimentary basins.

  1. Ground-motion modeling of Hayward fault scenario earthquakes, part II: Simulation of long-period and broadband ground motions

    USGS Publications Warehouse

    Aagaard, Brad T.; Graves, Robert W.; Rodgers, Arthur; Brocher, Thomas M.; Simpson, Robert W.; Dreger, Douglas; Petersson, N. Anders; Larsen, Shawn C.; Ma, Shuo; Jachens, Robert C.

    2010-01-01

    We simulate long-period (T>1.0–2.0 s) and broadband (T>0.1 s) ground motions for 39 scenario earthquakes (Mw 6.7–7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault, we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions, compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area, with about 50% of the urban area experiencing modified Mercalli intensity VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland earthquake and the 2007 Mw 5.45 Alum Rock earthquake show that the U.S. Geological Survey’s Bay Area Velocity Model version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area for Hayward fault earthquakes, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground motions for the suite of scenarios exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground motions display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground motions are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-motion prediction equations. We attribute much of this difference to the seismic velocity structure in the San Francisco Bay area and how the NGA models account for basin amplification; the NGA relations may underpredict amplification in shallow sedimentary basins. The simulations also suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by increasing the areal extent of rupture directivity with period.

  2. Stochastic ground motion simulation

    USGS Publications Warehouse

    Rezaeian, Sanaz; Xiaodan, Sun

    2014-01-01

    Strong earthquake ground motion records are fundamental in engineering applications. Ground motion time series are used in response-history dynamic analysis of structural or geotechnical systems. In such analysis, the validity of predicted responses depends on the validity of the input excitations. Ground motion records are also used to develop ground motion prediction equations(GMPEs) for intensity measures such as spectral accelerations that are used in response-spectrum dynamic analysis. Despite the thousands of available strong ground motion records, there remains a shortage of records for large-magnitude earthquakes at short distances or in specific regions, as well as records that sample specific combinations of source, path, and site characteristics.

  3. Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV

    SciTech Connect

    I. Wong

    2004-11-05

    This report describes a site-response model and its implementation for developing earthquake ground motion input for preclosure seismic design and postclosure assessment of the proposed geologic repository at Yucca Mountain, Nevada. The model implements a random-vibration theory (RVT), one-dimensional (1D) equivalent-linear approach to calculate site response effects on ground motions. The model provides results in terms of spectral acceleration including peak ground acceleration, peak ground velocity, and dynamically-induced strains as a function of depth. In addition to documenting and validating this model for use in the Yucca Mountain Project, this report also describes the development of model inputs, implementation of the model, its results, and the development of earthquake time history inputs based on the model results. The purpose of the site-response ground motion model is to incorporate the effects on earthquake ground motions of (1) the approximately 300 m of rock above the emplacement levels beneath Yucca Mountain and (2) soil and rock beneath the site of the Surface Facilities Area. A previously performed probabilistic seismic hazard analysis (PSHA) (CRWMS M&O 1998a [DIRS 103731]) estimated ground motions at a reference rock outcrop for the Yucca Mountain site (Point A), but those results do not include these site response effects. Thus, the additional step of applying the site-response ground motion model is required to develop ground motion inputs that are used for preclosure and postclosure purposes.

  4. Amateur football pitches: mechanical properties of the natural ground and of different artificial turf infills and their biomechanical implications.

    PubMed

    Zanetti, Elisabetta M; Bignardi, Cristina; Franceschini, Giordano; Audenino, Alberto L

    2013-01-01

    Artificial turf is being used more and more often. It is more available than natural turf for use, requires much less maintenance and new products are able to comply with sport performance and athletes' safety. The purpose of this paper is to compare the mechanical and biomechanical responses of two different artificial turf infills (styrene butadiene rubber, from granulated vehicle tires, and thermoplastic rubber granules) and to compare them to the performance of natural fields where amateurs play (beaten earth, substantially). Three mechanical parameters have been calculated from laboratory tests: energy storage, energy losses and surface traction coefficient; results have been correlated with peak accelerations recorded on an instrumented athlete, on the field. The natural ground proved to be stiffer (-15% penetration depth for a given load), and to have a lower dynamic traction coefficient (-48%); the different kinds of infill showed significantly different stiffnesses (varying by more than 23%) and damping behaviour (varying by more than 31%). In running, peak vertical accelerations were lowest in the artificial ground with thermoplastic rubber granules, while, in slalom, both artificial grounds produced higher horizontal peak accelerations compared to the natural ground. Results are discussed in terms of their implications for athletic performance and injury risk. PMID:23230960

  5. Using Tremor to Predict Strong Ground Motion

    NASA Astrophysics Data System (ADS)

    Baltay, A.; Asawachaisujja, S.; Beroza, G. C.

    2012-12-01

    Due to its widespread occurrence, frequency content, and location, tectonic tremor presents an exceptional opportunity to test and improve strong ground motion attenuation relations for subduction zones. We characterize the amplitude of thousands of individual tremor events to constrain the distance attenuation relationship of peak ground acceleration (PGA) and peak ground velocity (PGV) of tremor for application to strong ground motion prediction. Ground motion prediction equations (GMPE) relate ground motion amplitude to earthquake magnitude and distance, and are critically important for creating seismic hazard maps. In practice, GMPEs are determined empirically with earthquake data, recorded at many stations. In some areas of high earthquake hazard, such as Cascadia, the data set of recorded earthquakes for ground motion prediction is extremely sparse. Tectonic tremor, however, occurs frequently and abundantly in many subduction zones, including Cascadia. Moreover, the tremor band of 1-10 Hz, corresponds precisely to the frequency band of greatest interest for engineering seismology. Finally, tremor is thought to occur at or near the down-dip limit of rupture in large megathrust earthquakes, which is the area that is likely to control high frequency shaking in large earthquakes. Tremor in Cascadia is strong enough to be recorded at borehole stations of the Plate Boundary Observatory to distances of nearly 200 km, which is sufficient to place important constraints on ground motion decay with distance. We characterize the amplitude of thousands of individual tremor events occurring nearly continuously throughout an ETS event, using tremor locations and timings from independently determined catalogs [Wech and Creager, 2008]. Because tremor bursts do not have a defined absolute magnitude, we normalize all events to a reference magnitude. PGA and PGV for tremor shows a distance decay that is similar to subduction-zone-specific GMPEs developed from both data and

  6. New Ground Motion Prediction Models for Caucasus Region

    NASA Astrophysics Data System (ADS)

    Jorjiashvili, N.

    2012-12-01

    The Caucasus is a region of numerous natural hazards and ensuing disasters. Analysis of the losses due to past disasters indicates the those most catastrophic in the region have historically been due to strong earthquakes. Estimation of expected ground motion is a fundamental earthquake hazard assessment. The most commonly used parameter for attenuation relation is peak ground acceleration because this parameter gives useful information for Seismic Hazard Assessment. Because of this, many peak ground acceleration attenuation relations have been developed by different authors. Besides, a few attenuation relations were developed for Caucasus region: Ambraseys et al. (1996,2005) which were based on entire European region and they were not focused locally on Caucasus Region; Smit et.al. (2000) that was based on a small amount of acceleration data that really is not enough. Since 2003 construction of Georgian Digital Seismic Network has started with the help of number of International organizations, Projects and Private companies. The works conducted involved scientific as well as organizational activities: Resolving technical problems concerning communication and data transmission. Thus, today we have a possibility to get real time data and make scientific research based on digital seismic data. Generally, ground motion and damage are influenced by the magnitude of the earthquake, the distance from the seismic source to site, the local ground conditions and the characteristics of buildings. Estimation of expected ground motion is a fundamental earthquake hazard assessment. This is the reason why this topic is emphasized in this study. In this study new GMP models are obtained based on new data from Georgian seismic network and also from neighboring countries. Estimation of models are obtained by classical, statistical way, regression analysis. Also site ground conditions are considered because the same earthquake recorded at the same distance may cause different damage

  7. How to use your peak flow meter

    MedlinePlus

    Peak flow meter - how to use; Asthma - peak flow meter; Reactive airway disease - peak flow meter; Bronchial asthma - peak flow meter ... your airways are narrowed and blocked due to asthma, your peak flow values drop. You can check ...

  8. Plasma accelerators

    SciTech Connect

    Ruth, R.D.; Chen, P.

    1986-03-01

    In this paper we discuss plasma accelerators which might provide high gradient accelerating fields suitable for TeV linear colliders. In particular we discuss two types of plasma accelerators which have been proposed, the Plasma Beat Wave Accelerator and the Plasma Wake Field Accelerator. We show that the electric fields in the plasma for both schemes are very similar, and thus the dynamics of the driven beams are very similar. The differences appear in the parameters associated with the driving beams. In particular to obtain a given accelerating gradient, the Plasma Wake Field Accelerator has a higher efficiency and a lower total energy for the driving beam. Finally, we show for the Plasma Wake Field Accelerator that one can accelerate high quality low emittance beams and, in principle, obtain efficiencies and energy spreads comparable to those obtained with conventional techniques.

  9. Biomechanical Insights Into Differences Between the Mid-Acceleration and Maximum Velocity Phases of Sprinting.

    PubMed

    Yu, Jiabin; Sun, Yuliang; Yang, Chen; Wang, Donghai; Yin, Keyi; Herzog, Walter; Liu, Yu

    2016-07-01

    Yu, J, Sun, Y, Yang, C, Wang, D, Yin, K, Herzog, W, and Liu, Y. Biomechanical insights into differences between the mid-acceleration and maximum velocity phases of sprinting. J Strength Cond Res 30(7): 1906-1916, 2016-Investigating the differences between distinct phases of sprint running may increase the knowledge about the specific physical abilities needed for different phases of sprinting. Differences between the mid-acceleration and maximum velocity phases of sprint running have not yet been adequately investigated. Twenty male sprinters performed maximum-effort sprint runs, and measurements were made at 12 m from start for the mid-acceleration phase and at 40 m from the start for the maximum velocity phase. Kinematic data and ground reaction forces (GRFs) were collected at a rate of 200 and 1000 Hz, respectively. Intersegmental dynamics analysis was performed to investigate the interaction of muscle torque (MUS) with other passive torques. The peak horizontal braking force was significantly lower for the acceleration compared with that for the maximal velocity phase, whereas the peak horizontal propulsive force was similar for both phases. The peak MUS at the hip and knee joints for the braking phase was significantly smaller in the acceleration phase than in the maximum velocity phase. In conclusion, compared with the maximum velocity phase, the lower horizontal braking force was the primary cause for the increase in running velocity during the mid-acceleration phase. The force produced by lower limb muscles required to counteract external torques caused by the horizontal braking force in the braking phase was smaller during the acceleration phase than the maximum velocity phase. Therefore, training aimed at reducing the horizontal braking force might be more important than increasing the force produced by the lower limb muscles for success of the mid-acceleration phase. PMID:27331914

  10. Two classes of speculative peaks

    NASA Astrophysics Data System (ADS)

    Roehner, Bertrand M.

    2001-10-01

    Speculation not only occurs in financial markets but also in numerous other markets, e.g. commodities, real estate, collectibles, and so on. Such speculative movements result in price peaks which share many common characteristics: same order of magnitude of duration with respect to amplitude, same shape (the so-called sharp-peak pattern). Such similarities suggest (at least as a first approximation) a common speculative behavior. However, a closer examination shows that in fact there are (at least) two distinct classes of speculative peaks. For the first, referred to as class U, (i) the amplitude of the peak is negatively correlated with the price at the start of the peak (ii) the ensemble coefficient of variation exhibits a trough. Opposite results are observed for the second class that we refer to as class S. Once these empirical observations have been made we try to understand how they should be interpreted. First, we show that the two properties are in fact related in the sense that the second is a consequence of the first. Secondly, by listing a number of cases belonging to each class we observe that the markets in the S-class offer collection of items from which investors can select those they prefer. On the contrary, U-markets consist of undifferentiated products for which a selection cannot be made in the same way. All prices considered in the paper are real (i.e., deflated) prices.

  11. Hubbert's Peak: A Physicist's View

    NASA Astrophysics Data System (ADS)

    McDonald, Richard

    2011-11-01

    Oil and its by-products, as used in manufacturing, agriculture, and transportation, are the lifeblood of today's 7 billion-person population and our 65T world economy. Despite this importance, estimates of future oil production seem dominated by wishful thinking rather than quantitative analysis. Better studies are needed. In 1956, Dr. M.King Hubbert proposed a theory of resource production and applied it successfully to predict peak U.S. oil production in 1970. Thus, the peak of oil production is referred to as ``Hubbert's Peak.'' Prof. Al Bartlett extended this work in publications and lectures on population and oil. Both Hubbert and Bartlett place peak world oil production at a similar time, essentially now. This paper extends this line of work to include analyses of individual countries, inclusion of multiple Gaussian peaks, and analysis of reserves data. While this is not strictly a predictive theory, we will demonstrate a ``closed'' story connecting production, oil-in-place, and reserves. This gives us the ``most likely'' estimate of future oil availability. Finally, we will comment on synthetic oil and the possibility of carbon-neutral synthetic oil for a sustainable future.

  12. Ground Operations

    NASA Technical Reports Server (NTRS)

    Eastman, Randy

    2000-01-01

    The contents include: 1) Integrated Space Transportation; 2) Fourth Generation Reusable Launch Vehicle (RLV) Research; 3) Ground Operations; 4) Ground Operations Technologies; 5) Sensors; and 6) Umbilicals. This paper is presented in viewgraph form.

  13. Peak finding using biorthogonal wavelets

    SciTech Connect

    Tan, C.Y.

    2000-02-01

    The authors show in this paper how they can find the peaks in the input data if the underlying signal is a sum of Lorentzians. In order to project the data into a space of Lorentzian like functions, they show explicitly the construction of scaling functions which look like Lorentzians. From this construction, they can calculate the biorthogonal filter coefficients for both the analysis and synthesis functions. They then compare their biorthogonal wavelets to the FBI (Federal Bureau of Investigations) wavelets when used for peak finding in noisy data. They will show that in this instance, their filters perform much better than the FBI wavelets.

  14. Multimegawatt cyclotron autoresonance accelerator

    SciTech Connect

    Hirshfield, J.L.; LaPointe, M.A.; Ganguly, A.K.; Yoder, R.B.; Wang, C.

    1996-05-01

    Means are discussed for generation of high-quality multimegawatt gyrating electron beams using rf gyroresonant acceleration. TE{sub 111}-mode cylindrical cavities in a uniform axial magnetic field have been employed for beam acceleration since 1968; such beams have more recently been employed for generation of radiation at harmonics of the gyration frequency. Use of a TE{sub 11}-mode waveguide for acceleration, rather than a cavity, is discussed. It is shown that the applied magnetic field and group velocity axial tapers allow resonance to be maintained along a waveguide, but that this is impractical in a cavity. In consequence, a waveguide cyclotron autoresonance accelerator (CARA) can operate with near-100{percent} efficiency in power transfer from rf source to beam, while cavity accelerators will, in practice, have efficiency values limited to about 40{percent}. CARA experiments are described in which an injected beam of up to 25 A, 95 kV has had up to 7.2 MW of rf power added, with efficiencies of up to 96{percent}. Such levels of efficiency are higher than observed previously in any fast-wave interaction, and are competitive with efficiency values in industrial linear accelerators. Scaling arguments suggest that good quality gyrating megavolt beams with peak and average powers of 100 MW and 100 kW can be produced using an advanced CARA, with applications in the generation of high-power microwaves and for possible remediation of flue gas pollutants. {copyright} {ital 1996 American Institute of Physics.}

  15. Measuring Your Peak Flow Rate

    MedlinePlus

    ... meter. Proper cleaning with mild detergent in hot water will keep your peak flow meter working accurately and may keep you healthier. Related Content News: American Lung Association Applauds EPA’s Update to Cross-State Air Pollution Rule News: American Lung Association Invests More Than $ ...

  16. Peak Stress Testing Protocol Framework

    EPA Science Inventory

    Treatment of peak flows during wet weather is a common challenge across the country for municipal wastewater utilities with separate and/or combined sewer systems. Increases in wastewater flow resulting from infiltration and inflow (I/I) during wet weather events can result in op...

  17. Hubbert's Peak -- A Physicist's View

    NASA Astrophysics Data System (ADS)

    McDonald, Richard

    2011-04-01

    Oil, as used in agriculture and transportation, is the lifeblood of modern society. It is finite in quantity and will someday be exhausted. In 1956, Hubbert proposed a theory of resource production and applied it successfully to predict peak U.S. oil production in 1970. Bartlett extended this work in publications and lectures on the finite nature of oil and its production peak and depletion. Both Hubbert and Bartlett place peak world oil production at a similar time, essentially now. Central to these analyses are estimates of total ``oil in place'' obtained from engineering studies of oil reservoirs as this quantity determines the area under the Hubbert's Peak. Knowing the production history and the total oil in place allows us to make estimates of reserves, and therefore future oil availability. We will then examine reserves data for various countries, in particular OPEC countries, and see if these data tell us anything about the future availability of oil. Finally, we will comment on synthetic oil and the possibility of carbon-neutral synthetic oil for a sustainable future.

  18. Implications of the Northridge earthquake for strong ground motions from thrust faults

    USGS Publications Warehouse

    Somerville, P.; Saikia, C.; Wald, D.; Graves, R.

    1996-01-01

    The peak accelerations recorded on alluvial sites during the Northridge earthquake were about 50% larger than the median value predicted by current empirical attenuation relations at distances less than about 30 km. This raises the question of whether the ground motions from the Northridge earthquake are anomalous for thrust events or are representative of ground motions expected in future thrust earthquakes. Since the empirical data base contains few strong-motion records close to large-thrust earthquakes, it is difficult to assess whether the Northridge ground motions are anomalous based on recorded data alone. For this reason, we have used a broadband strong-motion simulation procedure to help assess whether the ground motions were anomalous. The simulation procedure has been validated against a large body of strong-motion data from California earthquakes, and so we expect it to produce accurate estimates of ground motions for any given rupture scenario, including blind-thrust events for which no good precedent existed in the strong-motion data base until the occurrence of the Northridge earthquake. The ground motions from the Northridge earthquake and our simulations of these ground motions have a similar pattern of departure from empirical attenuation relations for thrust earthquakes: the peak accelerations are at about the 84th percentile level for distances within 20 to 30 km and follow the median level for larger distances. This same pattern of departure from empirical attenuation relations was obtained in our simulations of the peak accelerations of an Elysian Park blind-thrust event prior to the occurrence of the Northridge earthquake. Since we are able to model this pattern with broadband simulations, and had done so before the Northridge earthquake occurred, this suggests that the Northridge strong-motion records are not anomalous and are representative of ground motions close to thrust faults. Accordingly, it seems appropriate to include these

  19. Seismic fragility formulations for segmented buried pipeline systems including the impact of differential ground subsidence

    SciTech Connect

    Pineda Porras, Omar Andrey; Ordaz, Mario

    2009-01-01

    Though Differential Ground Subsidence (DGS) impacts the seismic response of segmented buried pipelines augmenting their vulnerability, fragility formulations to estimate repair rates under such condition are not available in the literature. Physical models to estimate pipeline seismic damage considering other cases of permanent ground subsidence (e.g. faulting, tectonic uplift, liquefaction, and landslides) have been extensively reported, not being the case of DGS. The refinement of the study of two important phenomena in Mexico City - the 1985 Michoacan earthquake scenario and the sinking of the city due to ground subsidence - has contributed to the analysis of the interrelation of pipeline damage, ground motion intensity, and DGS; from the analysis of the 48-inch pipeline network of the Mexico City's Water System, fragility formulations for segmented buried pipeline systems for two DGS levels are proposed. The novel parameter PGV{sup 2}/PGA, being PGV peak ground velocity and PGA peak ground acceleration, has been used as seismic parameter in these formulations, since it has shown better correlation to pipeline damage than PGV alone according to previous studies. By comparing the proposed fragilities, it is concluded that a change in the DGS level (from Low-Medium to High) could increase the pipeline repair rates (number of repairs per kilometer) by factors ranging from 1.3 to 2.0; being the higher the seismic intensity the lower the factor.

  20. Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss

    NASA Astrophysics Data System (ADS)

    Lawrence, D. M.; Slater, A. G.; Tomas, R. A.; Holland, M. M.; Deser, C.

    2008-12-01

    Coupled climate models and recent observational evidence suggest that Arctic sea ice may undergo abrupt periods of loss during the next fifty years. Here, we evaluate how rapid sea ice loss affects terrestrial Arctic climate and ground thermal state in the Community Climate System Model. We find that simulated western Arctic land warming trends during rapid sea ice loss are 3.5 times greater than secular 21st century climate- change trends. The accelerated warming signal penetrates up to 1500km inland and is apparent throughout most of the year, peaking in autumn. Idealized experiments using the Community Land Model, with improved permafrost dynamics, indicate that an accelerated warming period substantially increases ground heat accumulation. Enhanced heat accumulation leads to rapid degradation of warm permafrost and may increase the vulnerability of colder permafrost to degradation under continued warming. Taken together, these results imply a direct link between rapid sea ice loss and permafrost health.

  1. Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss

    NASA Astrophysics Data System (ADS)

    Lawrence, David M.; Slater, Andrew G.; Tomas, Robert A.; Holland, Marika M.; Deser, Clara

    2008-06-01

    Coupled climate models and recent observational evidence suggest that Arctic sea ice may undergo abrupt periods of loss during the next fifty years. Here, we evaluate how rapid sea ice loss affects terrestrial Arctic climate and ground thermal state in the Community Climate System Model. We find that simulated western Arctic land warming trends during rapid sea ice loss are 3.5 times greater than secular 21st century climate-change trends. The accelerated warming signal penetrates up to 1500 km inland and is apparent throughout most of the year, peaking in autumn. Idealized experiments using the Community Land Model, with improved permafrost dynamics, indicate that an accelerated warming period substantially increases ground heat accumulation. Enhanced heat accumulation leads to rapid degradation of warm permafrost and may increase the vulnerability of colder permafrost to degradation under continued warming. Taken together, these results imply a link between rapid sea ice loss and permafrost health.

  2. Strong ground motion in the Kathmandu Valley during the 2015 Gorkha, Nepal, earthquake

    NASA Astrophysics Data System (ADS)

    Takai, Nobuo; Shigefuji, Michiko; Rajaure, Sudhir; Bijukchhen, Subeg; Ichiyanagi, Masayoshi; Dhital, Megh Raj; Sasatani, Tsutomu

    2016-01-01

    On 25 April 2015, a large earthquake of Mw 7.8 occurred along the Main Himalayan Thrust fault in central Nepal. It was caused by a collision of the Indian Plate beneath the Eurasian Plate. The epicenter was near the Gorkha region, 80 km northwest of Kathmandu, and the rupture propagated toward east from the epicentral region passing through the sediment-filled Kathmandu Valley. This event resulted in over 8000 fatalities, mostly in Kathmandu and the adjacent districts. We succeeded in observing strong ground motions at our four observation sites (one rock site and three sedimentary sites) in the Kathmandu Valley during this devastating earthquake. While the observed peak ground acceleration values were smaller than the predicted ones that were derived from the use of a ground motion prediction equation, the observed peak ground velocity values were slightly larger than the predicted ones. The ground velocities observed at the rock site (KTP) showed a simple velocity pulse, resulting in monotonic-step displacements associated with the permanent tectonic offset. The vertical ground velocities observed at the sedimentary sites had the same pulse motions that were observed at the rock site. In contrast, the horizontal ground velocities as well as accelerations observed at three sedimentary sites showed long duration with conspicuous long-period oscillations, due to the valley response. The horizontal valley response was characterized by large amplification (about 10) and prolonged oscillations. However, the predominant period and envelope shape of their oscillations differed from site to site, indicating a complicated basin structure. Finally, on the basis of the velocity response spectra, we show that the horizontal long-period oscillations on the sedimentary sites had enough destructive power to damage high-rise buildings with natural periods of 3 to 5 s.

  3. Prediction of spectral acceleration response ordinates based on PGA attenuation

    USGS Publications Warehouse

    Graizer, V.; Kalkan, E.

    2009-01-01

    Developed herein is a new peak ground acceleration (PGA)-based predictive model for 5% damped pseudospectral acceleration (SA) ordinates of free-field horizontal component of ground motion from shallow-crustal earthquakes. The predictive model of ground motion spectral shape (i.e., normalized spectrum) is generated as a continuous function of few parameters. The proposed model eliminates the classical exhausted matrix of estimator coefficients, and provides significant ease in its implementation. It is structured on the Next Generation Attenuation (NGA) database with a number of additions from recent Californian events including 2003 San Simeon and 2004 Parkfield earthquakes. A unique feature of the model is its new functional form explicitly integrating PGA as a scaling factor. The spectral shape model is parameterized within an approximation function using moment magnitude, closest distance to the fault (fault distance) and VS30 (average shear-wave velocity in the upper 30 m) as independent variables. Mean values of its estimator coefficients were computed by fitting an approximation function to spectral shape of each record using robust nonlinear optimization. Proposed spectral shape model is independent of the PGA attenuation, allowing utilization of various PGA attenuation relations to estimate the response spectrum of earthquake recordings.

  4. METHOD OF PEAK CURRENT MEASUREMENT

    DOEpatents

    Baker, G.E.

    1959-01-20

    The measurement and recording of peak electrical currents are described, and a method for utilizing the magnetic field of the current to erase a portion of an alternating constant frequency and amplitude signal from a magnetic mediums such as a magnetic tapes is presented. A portion of the flux from the current carrying conductor is concentrated into a magnetic path of defined area on the tape. After the current has been recorded, the tape is played back. The amplitude of the signal from the portion of the tape immediately adjacent the defined flux area and the amplitude of the signal from the portion of the tape within the area are compared with the amplitude of the signal from an unerased portion of the tape to determine the percentage of signal erasure, and thereby obtain the peak value of currents flowing in the conductor.

  5. SPANISH PEAKS PRIMITIVE AREA, MONTANA.

    USGS Publications Warehouse

    Calkins, James A.; Pattee, Eldon C.

    1984-01-01

    A mineral survey of the Spanish Peaks Primitive Area, Montana, disclosed a small low-grade deposit of demonstrated chromite and asbestos resources. The chances for discovery of additional chrome resources are uncertain and the area has little promise for the occurrence of other mineral or energy resources. A reevaluation, sampling at depth, and testing for possible extensions of the Table Mountain asbestos and chromium deposit should be undertaken in the light of recent interpretations regarding its geologic setting.

  6. Energy saver prototype accelerating resonator

    SciTech Connect

    Kerns, Q.; May, M.; Miller, H.W.; Reid, J.; Turkot, F.; Webber, R.; Wildman, D.

    1981-06-01

    A fixed frequency rf accelerating resonator has been built and tested for the Fermilab Energy Saver. The design parameters and prototype resonator test results are given. The resonator features a high permeability nickel alloy resistor which damps unwanted modes and corona rolls designed with the aid of the computer code SUPERFISH. In bench measurements, the prototype resonator has achieved peak accelerating voltages of 500 kV for a 1% duty cycle and cw operation at 360 kV. 4 refs.

  7. Accelerated Reader.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO.

    This paper provides an overview of Accelerated Reader, a system of computerized testing and record-keeping that supplements the regular classroom reading program. Accelerated Reader's primary goal is to increase literature-based reading practice. The program offers a computer-aided reading comprehension and management program intended to motivate…

  8. Dielectric laser accelerators

    NASA Astrophysics Data System (ADS)

    England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.

    2014-10-01

    The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

  9. Effects of near-fault ground motions on the nonlinear behaviour of reinforced concrete framed buildings

    NASA Astrophysics Data System (ADS)

    Mazza, Mirko

    2015-07-01

    The design provisions of current seismic codes are generally not very accurate for assessing effects of near-fault ground motions on reinforced concrete (r.c.) spatial frames, because only far-fault ground motions are considered in the seismic codes. Strong near-fault earthquakes are characterized by long-duration (horizontal) pulses and high values of the ratio α PGA of the peak value of the vertical acceleration, PGAV, to the analogous value of the horizontal acceleration, PGAH, which can become critical for girders and columns. In this work, six- and twelve-storey r.c. spatial frames are designed according to the provisions of the Italian seismic code, considering the horizontal seismic loads acting (besides the gravity loads) alone or in combination with the vertical ones. The nonlinear seismic analysis of the test structures is performed using a step-by-step procedure based on a two-parameter implicit integration scheme and an initial stress-like iterative procedure. A lumped plasticity model based on the Haar-Kàrmàn principle is adopted to model the inelastic behaviour of the frame members. For the numerical investigation, five near-fault ground motions with high values of the acceleration ratio α PGA are considered. Moreover, following recent seismological studies, which allow the extraction of the largest (horizontal) pulse from a near-fault ground motion, five pulse-type (horizontal) ground motions are selected by comparing the original ground motion with the residual motion after the pulse has been extracted. The results of the nonlinear dynamic analysis carried out on the test structures highlighted that horizontal and vertical components of near-fault ground motions may require additional consideration in the seismic codes.

  10. The Sacramento Peak fast microphotometer

    NASA Technical Reports Server (NTRS)

    Arrambide, M. R.; Dunn, R. B.; Healy, A. W.; Porter, R.; Widener, A. L.; November, L. J.; Spence, G. E.

    1984-01-01

    The Sacramento Peak Observatory Fast Microphotometer translates an optical system that includes a laser and photodiode detector across the film to scan the Y direction. A stepping motor moves the film gate in the X direction. This arrangement affords high positional accuracy, low noise (0.002 RMS density units), modest speed (5000 points/second), large dynamic range (4.5 density units), high stability (0.005 density units), and low scattered light. The Fast Microphotometer is interfaced to the host computer by a 6502 microprocessor.

  11. Solar investigation at Terskol Peak

    NASA Astrophysics Data System (ADS)

    Burlov-Vasiljev, K. A.; Vasiljeva, I. E.

    2003-04-01

    During 1980--1990 regular observations of the solar disk spectrum and active solar structures were carried out with SEF-1 and ATsU-26 telescopes at Terskol Peak in the framework of the program ``Energy distribution in the solar spectrum in absolute energy units''. In order to refine the fine structure of telluric lines, observations with ATsU-26 telescope were carried out in parallel. This telescope was also used for the investigation of the solar active structures. In this paper the observational technique is described. The obtained results and energy distribution in the solar disk center in absolute energy units are presented.

  12. GRANITE PEAK ROADLESS AREA, CALIFORNIA.

    USGS Publications Warehouse

    Huber, Donald F.; Thurber, Horace K.

    1984-01-01

    The Granite Peak Roadless Area occupies an area of about 5 sq mi in the southern part of the Trinity Alps of the Klamath Mountains, about 12 mi north-northeast of Weaverville, California. Rock and stream-sediment samples were analyzed. All streams draining the roadless area were sampled and representative samples of the rock types in the area were collected. Background values were established for each element and anomalous values were examined within their geologic settings and evaluated for their significance. On the basis of mineral surveys there seems little likelihood for the occurrence of mineral or energy resources.

  13. Maxometers (peak wind speed anemometers)

    NASA Technical Reports Server (NTRS)

    Kaufman, J. W.; Camp, D. W.; Turner, R. E. (Inventor)

    1973-01-01

    An instrument for measuring peak wind speeds under severe environmental conditions is described, comprising an elongated cylinder housed in an outer casing. The cylinder contains a piston attached to a longitudinally movable guided rod having a pressure disk mounted on one projecting end. Wind pressure against the pressure disk depresses the movable rod. When the wind reaches its maximum speed, the rod is locked by a ball clutch mechanism in the position of maximum inward movement. Thereafter maximum wind speed or pressure readings may be taken from calibrated indexing means.

  14. Diffusive Shock Acceleration and Reconnection Acceleration Processes

    NASA Astrophysics Data System (ADS)

    Zank, G. P.; Hunana, P.; Mostafavi, P.; Le Roux, J. A.; Li, Gang; Webb, G. M.; Khabarova, O.; Cummings, A.; Stone, E.; Decker, R.

    2015-12-01

    Shock waves, as shown by simulations and observations, can generate high levels of downstream vortical turbulence, including magnetic islands. We consider a combination of diffusive shock acceleration (DSA) and downstream magnetic-island-reconnection-related processes as an energization mechanism for charged particles. Observations of electron and ion distributions downstream of interplanetary shocks and the heliospheric termination shock (HTS) are frequently inconsistent with the predictions of classical DSA. We utilize a recently developed transport theory for charged particles propagating diffusively in a turbulent region filled with contracting and reconnecting plasmoids and small-scale current sheets. Particle energization associated with the anti-reconnection electric field, a consequence of magnetic island merging, and magnetic island contraction, are considered. For the former only, we find that (i) the spectrum is a hard power law in particle speed, and (ii) the downstream solution is constant. For downstream plasmoid contraction only, (i) the accelerated spectrum is a hard power law in particle speed; (ii) the particle intensity for a given energy peaks downstream of the shock, and the distance to the peak location increases with increasing particle energy, and (iii) the particle intensity amplification for a particular particle energy, f(x,c/{c}0)/f(0,c/{c}0), is not 1, as predicted by DSA, but increases with increasing particle energy. The general solution combines both the reconnection-induced electric field and plasmoid contraction. The observed energetic particle intensity profile observed by Voyager 2 downstream of the HTS appears to support a particle acceleration mechanism that combines both DSA and magnetic-island-reconnection-related processes.

  15. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  16. Representation of bidirectional ground motions for design spectra in building codes

    USGS Publications Warehouse

    Stewart, Jonathan P.; Abrahamson, Norman A.; Atkinson, Gail M.; Beker, Jack W.; Boore, David M.; Bozorgnia, Yousef; Campbell, Kenneth W.; Comartin, Craig D.; Idriss, I.M.; Lew, Marshall; Mehrain, Michael; Moehle, Jack P.; Naeim, Farzad; Sabol, Thomas A.

    2011-01-01

    The 2009 NEHRP Provisions modified the definition of horizontal ground motion from the geometric mean of spectral accelerations for two components to the peak response of a single lumped mass oscillator regardless of direction. These maximum-direction (MD) ground motions operate under the assumption that the dynamic properties of the structure (e.g., stiffness, strength) are identical in all directions. This assumption may be true for some in-plan symmetric structures, however, the response of most structures is dominated by modes of vibration along specific axes (e.g., longitudinal and transverse axes in a building), and often the dynamic properties (especially stiffness) along those axes are distinct. In order to achieve structural designs consistent with the collapse risk level given in the NEHRP documents, we argue that design spectra should be compatible with expected levels of ground motion along those principal response axes. The use of MD ground motions effectively assumes that the azimuth of maximum ground motion coincides with the directions of principal structural response. Because this is unlikely, design ground motions have lower probability of occurrence than intended, with significant societal costs. We recommend adjustments to make design ground motions compatible with target risk levels.

  17. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  18. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  19. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  20. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  1. Sprint Acceleration Mechanics: The Major Role of Hamstrings in Horizontal Force Production

    PubMed Central

    Morin, Jean-Benoît; Gimenez, Philippe; Edouard, Pascal; Arnal, Pierrick; Jiménez-Reyes, Pedro; Samozino, Pierre; Brughelli, Matt; Mendiguchia, Jurdan

    2015-01-01

    Recent literature supports the importance of horizontal ground reaction force (GRF) production for sprint acceleration performance. Modeling and clinical studies have shown that the hip extensors are very likely contributors to sprint acceleration performance. We experimentally tested the role of the hip extensors in horizontal GRF production during short, maximal, treadmill sprint accelerations. Torque capabilities of the knee and hip extensors and flexors were assessed using an isokinetic dynamometer in 14 males familiar with sprint running. Then, during 6-s sprints on an instrumented motorized treadmill, horizontal and vertical GRF were synchronized with electromyographic (EMG) activity of the vastus lateralis, rectus femoris, biceps femoris, and gluteus maximus averaged over the first half of support, entire support, entire swing and end-of-swing phases. No significant correlations were found between isokinetic or EMG variables and horizontal GRF. Multiple linear regression analysis showed a significant relationship (P = 0.024) between horizontal GRF and the combination of biceps femoris EMG activity during the end of the swing and the knee flexors eccentric peak torque. In conclusion, subjects who produced the greatest amount of horizontal force were both able to highly activate their hamstring muscles just before ground contact and present high eccentric hamstring peak torque capability. PMID:26733889

  2. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion

    NASA Astrophysics Data System (ADS)

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-02-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green’s function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s2 in the horizontal direction and 0.0917 m/s2 in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0-7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals.

  3. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion.

    PubMed

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-01-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green's function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s(2) in the horizontal direction and 0.0917 m/s(2) in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0-7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals. PMID:26884136

  4. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion

    PubMed Central

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-01-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green’s function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s2 in the horizontal direction and 0.0917 m/s2 in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0–7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals. PMID:26884136

  5. Observations and stochastic modelling of strong ground motions for the 2011 October 23 Mw 7.1 Van, Turkey, earthquake

    NASA Astrophysics Data System (ADS)

    Akinci, Aybige; Antonioli, Andrea

    2013-03-01

    The 2011 October 23 Van earthquake occurred at 13:41 local time in Eastern Turkey with an epicentre at 43.36oE, 38.76oN (Kandilli Observatory Earthquake Research Institute (KOERI)), 16 km north-northeast of the city of Van, killing around 604 people and leaving thousands homeless. This work presents an overview of the main features of the seismic ground shaking during the Van earthquake. We analyse the ground motion characteristics of the mainshock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations (SA, 5 per cent of critical damping). In order to understand the characteristics of the ground motions induced by the mainshock, we also study the site response of the strong motion stations that recorded the seismic sequence. The lack of seismic recordings in this area imposes major constraints on the computation of reliable seismic hazard estimates for sites in this part of the country. Towards this aim, we have used a stochastic method to generate high frequency ground motion synthetics for the Mw 7.1 Van 2011 earthquake. The source mechanism of the Van event and regional wave propagation parameters are constrained from the available and previous studies. The selected model parameters are then validated against recordings. We also computed the residuals for the ground motion parameters in terms of PGA and PGV at each station and the model parameter bias by averaging the residuals over all the stations. The attenuation of the simulated ground motion parameters is compared with recent global and regional ground motion prediction equations. Finally, since it has been debated whether the earthquake of November 9 was an aftershock of the October 23 earthquake, we examine whether static variation of Coulomb stress could contribute to the observed aftershock triggering during the 2011 Van Lake sequence. Comparison with empirical ground motion prediction illustrated that the observed PGA data decay faster than the global

  6. Accelerator Technology Division progress report, FY 1992

    SciTech Connect

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-07-01

    This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  7. Ground-motion parameters of the southwestern Indiana earthquake of 18 June 2002 and the disparity between the observed and predicted values

    USGS Publications Warehouse

    Street, R.; Wiegand, J.; Woolery, E.W.; Hart, P.

    2005-01-01

    The M 4.5 southwestern Indiana earthquake of 18 June 2002 triggered 46 blast monitors in Indiana, Illinois, and Kentucky. The resulting free-field particle velocity records, along with similar data from previous earthquakes in the study area, provide a clear standard for judging the reliability of current maps for predicting ground motions greater than 2 Hz in southwestern Indiana and southeastern Illinois. Peak horizontal accelerations and velocities, and 5% damped pseudo-accelerations for the earthquake, generally exceeded ground motions predicted for the top of the bedrock by factors of 2 or more, even after soil amplifications were taken into consideration. It is suggested, but not proven, that the low shear-wave velocity and weathered bedrock in the area are also amplifying the higher-frequency ground motions that have been repeatedly recorded by the blast monitors in the study area. It is also shown that there is a good correlation between the peak ground motions and 5% pseudo-accelerations recorded for the event, and the Modified Mercalli intensities interpreted for the event by the U.S. Geological Survey.

  8. Pulsed electromagnetic acceleration

    NASA Technical Reports Server (NTRS)

    Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

    1973-01-01

    Direct measurements of the power deposited in the anode of a multimegawatt MPD accelerator using thermocouples attached to a thin shell anode reveal a dramatic decrease in the fractional anode power from 50% at 200 KW input power to less than 10% at 20 MW power. The corresponding local power flux peak at a value of 10,000 W/sq cm at the lip of the anode exhaust orifice, a distribution traced to a corresponding peak in the local current density at the anode. A comparison of voltage-current characteristics and spectral photographs of the MPD discharge using quartz, boron nitride and plexiglas insulators with various mass injection configurations led to the identification of different voltage modes and regions of ablation free operation. The technique of piezoelectric impact pressure measurement in the MPD exhaust flow was refined to account for the effects due to probe yaw angle.

  9. Ion wave breaking acceleration

    NASA Astrophysics Data System (ADS)

    Liu, B.; Meyer-ter-Vehn, J.; Bamberg, K.-U.; Ma, W. J.; Liu, J.; He, X. T.; Yan, X. Q.; Ruhl, H.

    2016-07-01

    Laser driven ion wave breaking acceleration (IWBA) in plasma wakefields is investigated by means of a one-dimensional (1D) model and 1D/3D particle-in-cell (PIC) simulations. IWBA operates in relativistic transparent plasma for laser intensities in the range of 1020- 1023 W /cm2 . The threshold for IWBA is identified in the plane of plasma density and laser amplitude. In the region just beyond the threshold, self-injection takes place only for a fraction of ions and in a limited time period. This leads to well collimated ion pulses with peaked energy spectra, in particular for 3D geometry.

  10. NOx control buys to peak in `98

    SciTech Connect

    McIlvaine, R.W.

    1995-10-01

    Titles I and IV of the Clean Air Act provide the legislative framework for a huge NOx reduction program now in operation. This reduction will have a substantial effect in reducing ground-level ozone. A new McIlvaine report concludes that US utilities and industrial companies during the next 10 years will spend more than $800 million annually to meet CAA`s NOx-control regulations. Much of that investment will be for low-NOx burners, which minimize NOx formation. Many utilities and industrial boilers can be retrofitted with a new generation of burners; however, this technology achieves less than 50% NOx reduction. Post-combustion technologies, such as selective catalytic reduction and selective noncatalytic reduction, can reduce NOx as much as 90%. Therefore, plants needing greater NOx reduction will use post-combustion technologies, often in combination with low-NOx burners. The peak order year for NOx-control equipment will be 1998, primarily because Title IV of CAA requires utilities to comply by 2000. Many industrial sources also will be ordering equipment in 1998.

  11. Commissioning the GTA accelerator

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V. ); Connolly, R.; Weiss, R. (Gr

    1992-01-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth's magnetic field and travel in straight lines unless they enter the earth's atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -} beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.

  12. Commissioning the GTA accelerator

    SciTech Connect

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Brown, S.; Cole, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.; Johnson, K.F.; Kerstiens, D.; Little, C.; Lohsen, R.A.; Lloyd, S.; Lysenko, W.P.; Mottershead, C.T.; Neuschaefer, G.; Power, J.; Rusthoi, D.P.; Sandoval, D.P. Stevens, R.R. Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V.; Connolly, R.; Weiss, R.; Saadatmand, K.

    1992-09-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth`s magnetic field and travel in straight lines unless they enter the earth`s atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -} beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.

  13. Peaks in the Cosmic Microwave Background: Flat versus Open Models

    NASA Astrophysics Data System (ADS)

    Barreiro, R. B.; Sanz, J. L.; Martínez-González, E.; Cayón, L.; Silk, Joseph

    1997-03-01

    We present properties of the peaks (maxima) of the microwave background anisotropies expected in flat and open cold dark matter models. We obtain analytical expressions of several topological descriptors: mean number of maxima and the probability distribution of the Gaussian curvature and the eccentricity of the peaks. These quantities are calculated as functions of the radiation power spectrum, assuming a Gaussian distribution of temperature anisotropies. We present results for angular resolutions ranging from 5' to 20' (antenna FWHM), scales that are relevant for the MAP and COBRAS/SAMBA space missions and the ground-based interferometer experiments. Our analysis also includes the effects of noise. We find that the number of peaks can discriminate between standard cold dark matter models and that the Gaussian curvature distribution provides a useful test for these various models, whereas the eccentricity distribution cannot distinguish between them.

  14. The peak electromagnetic power radiated by lightning return strokes

    NASA Technical Reports Server (NTRS)

    Krider, E. P.; Guo, C.

    1983-01-01

    Estimates of the peak electromagnetic (EM) power radiated by return strokes have been made by integrating the Poynting vector of measured fields over an imaginary hemispherical surface that is centered on the lightning source, assuming that ground losses are negligible. Values of the peak EM power from first and subsequent strokes have means and standard deviations of 2 + or - 2 x 10 to the 10th and 3 + or - 4 x 10 to the 9th W, respectively. The average EM power that is radiated by subsequent strokes, at the time of the field peak, is about 2 orders of magnitude larger than the optical power that is radiated by these strokes in the wavelength interval from 0.4 to 1.1 micron; hence an upper limit to the radiative efficiency of a subsequent stroke is of the order of 1 percent or less at this time.

  15. Peak load management: Potential options

    SciTech Connect

    Englin, J.E.; De Steese, J.G.; Schultz, R.W.; Kellogg, M.A.

    1989-10-01

    This report reviews options that may be alternatives to transmission construction (ATT) applicable both generally and at specific locations in the service area of the Bonneville Power Administration (BPA). Some of these options have potential as specific alternatives to the Shelton-Fairmount 230-kV Reinforcement Project, which is the focus of this study. A listing of 31 peak load management (PLM) options is included. Estimated costs and normalized hourly load shapes, corresponding to the respective base load and controlled load cases, are considered for 15 of the above options. A summary page is presented for each of these options, grouped with respect to its applicability in the residential, commercial, industrial, and agricultural sectors. The report contains comments on PLM measures for which load shape management characteristics are not yet available. These comments address the potential relevance of the options and the possible difficulty that may be encountered in characterizing their value should be of interest in this investigation. The report also identifies options that could improve the efficiency of the three customer utility distribution systems supplied by the Shelton-Fairmount Reinforcement Project. Potential cogeneration options in the Olympic Peninsula are also discussed. These discussions focus on the options that appear to be most promising on the Olympic Peninsula. Finally, a short list of options is recommended for investigation in the next phase of this study. 9 refs., 24 tabs.

  16. 10 CFR 820.34 - Accelerated decision.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Accelerated decision. 820.34 Section 820.34 Energy DEPARTMENT OF ENERGY PROCEDURAL RULES FOR DOE NUCLEAR ACTIVITIES Enforcement Process § 820.34 Accelerated... facie case or other grounds that show no right to relief on the part of the Director. (b) Effect...

  17. Near-field ground motion of the 2002 Denali fault, Alaska, earthquake recorded at pump station 10

    USGS Publications Warehouse

    Ellsworth, W.L.; Celebi, M.; Evans, J.R.; Jensen, E.G.; Kayen, R.; Metz, M.C.; Nyman, D.J.; Roddick, J.W.; Spudich, P.; Stephens, C.D.

    2004-01-01

    A free-field recording of the Denali fault earthquake was obtained by the Alyeska Pipeline Service Company 3 km from the surface rupture of the Denali fault. The instrument, part of the monitoring and control system for the trans-Alaska pipeline, was located at Pump Station 10, approximately 85 km east of the epicenter. After correction for the measured instrument response, we recover a seismogram that includes a permanent displacement of 3.0 m. The recorded ground motion has relatively low peak acceleration (0.36 g) and very high peak velocity (180 cm/s). Nonlinear soil response may have reduced the peak acceleration to this 0.36 g value. Accelerations in excess of 0.1 g lasted for 10 s, with the most intense motion occurring during a 1.5-s interval when the rupture passed the site. The low acceleration and high velocity observed near the fault in this earthquake agree with observations from other recent large-magnitude earthquakes. ?? 2004, Earthquake Engineering Research Institute.

  18. Control of robot dynamics using acceleration control

    NASA Technical Reports Server (NTRS)

    Workman, G. L.; Prateru, S.; Li, W.; Hinman, Elaine

    1992-01-01

    Acceleration control of robotic devices can provide improvements to many space-based operations using flexible manipulators and to ground-based operations requiring better precision and efficiency than current industrial robots can provide. This paper reports on a preliminary study of acceleration measurement on robotic motion during parabolic flights on the NASA KC-135 and a parallel study of accelerations with and without gravity arising from computer simulated motions using TREETOPS software.

  19. Accelerator Technology Division progress report, FY 1993

    SciTech Connect

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-12-31

    This report discusses the following topics: A Next-Generation Spallation-Neutron Source; Accelerator Performance Demonstration Facility; APEX Free-Electron Laser Project; The Ground Test Accelerator (GTA) Program; Intense Neutron Source for Materials Testing; Linac Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Radio-Frequency Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operation.

  20. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  1. The September 19, 1985 Michoacan Earthquake: Aftershock acceleration data recorded by a temporary installation of strong motion instruments

    NASA Astrophysics Data System (ADS)

    Munguía, Luis; Simila, Gerry W.; McNally, Karen C.; Thompson, Howard

    1986-06-01

    We describe acceleration signals recorded for nine aftershocks of the September 19, 1985 Michoacan earthquake. To obtain this data set, three A-700 Teledyne-Geotech digital strong-motion instruments were operated temporarily at two sites on the José María Morelos (La Villita) Dam, and at a site located at about 12 km to the west of the town of Zihuatanejo. Peak horizontal accelerations of 0.005 g to 0.031 g were recorded at epicentral distances between 10 and 75 km, for earthquakes with magnitude (mb) between 4.5 and 5.3. It was observed that the peak accelerations recorded at a site on the embankment of the dam (near the crest ) are approximately three times those recorded on the abutment bedrock portion of the dam. Although these sites were spatially separated by no more than 300 m, differences among their records are also significant. Waveforms recorded at the embankment site look more complex than those from the abutment site. This fact, as well as the higher peak accelerations on the embankment, provides evidence of a strong influence of the structure of the dam on the ground motion at the embankment site.

  2. Determination of peak expiratory flow.

    PubMed

    Kano, S; Burton, D L; Lanteri, C J; Sly, P D

    1993-10-01

    It is still unknown whether peak expiratory flow (PEF) is determined by "wave speed" flow limitation in the airways. To investigate the influences of airway mechanical properties on PEF, five healthy adults performed maximal forced expiratory effort (MFEE) manoeuvres, in the standard manner and following breathholds at total lung capacity (TLC) of 2 s and 10 s. Oesophageal pressure (Poes) was measured as an index of respiratory effort. Subjects also performed a MFEE following a 10 s breathhold during which intrathoracic pressure was voluntarily raised by a Valsalva manoeuvre, which would increase transmural pressure and cross-sectional area of the extrathoracic airway. Additional MFEEs were performed with the neck fully flexed and extended, to change longitudinal tracheal tension. In separate studies, PEF was measured with a spirometer and with a pneumotachograph. Breathholds at TLC (2 s and 10 s), and neck flexion reduced PEF by a mean of 9.8% (SD 2.9%), 9.6% (SD 1.6%), and 8.7% (SD 2.8%), respectively, when measured with the spirometer. The same pattern of results was seen when measured with the pneumotachograph. These reductions occurred despite similar respiratory effort. Voluntarily raising intrathoracic pressure during a 10 s breathhold did not reverse a fall in PEF. MFEE manoeuvre with neck extension did not result in an increase in PEF, the group mean % changes being -3.0% (SD 5.0%). We conclude that these results do not allow the hypothesis that "wave-speed" (Vws) is reached at PEF to be rejected. A breathhold at TLC could increase airway wall compliance by allowing stress-relaxation of the airway, thus reducing the "Vws" achievable. PMID:8287953

  3. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  4. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  5. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  6. Earthquake scenario ground motions for the urban area of Evansville, Indiana

    USGS Publications Warehouse

    Haase, Jennifer S.; Nowack, Robert L.; Cramer, Chris H.; Boyd, Oliver S.; Bauer, Robert A.

    2011-01-01

    The Wabash Valley seismic zone and the New Madrid seismic zone are the closest large earthquake source zones to Evansville, Indiana. The New Madrid earthquakes of 1811-1812, over 180 kilometers (km) from Evansville, produced ground motions with a Modified Mercalli Intensity of VII near Evansville, the highest intensity observed in Indiana. Liquefaction evidence has been documented less than 40 km away from Evansville resulting from two large earthquakes in the past 12,000 years in the Wabash Valley. Two earthquake scenarios are described in this paper that demonstrate the expected ground motions for a 33×42-km region around Evansville based on a repeat earthquake from each of these source regions. We perform a one-dimensional analysis for a grid of sites that takes into account the amplification or deamplification of ground motion in the unconsolidated soil layer using a new three-dimensional model of seismic velocity and bedrock depth. There are significant differences in the calculated amplification from that expected for National Earthquake Hazard Reduction Program site class D conditions, with deamplification at many locations within the ancient bedrock valley underlying Evansville. Ground motions relative to the acceleration of gravity (g) in the Evansville area from a simulation of a magnitude (M) 7.7 New Madrid earthquake range from 0.15 to 0.25 g for peak ground acceleration, 0.14 to 0.7 g for 0.2-second (s) spectral acceleration, and 0.05 to 0.25 g for 1.0-s spectral acceleration. Ground motions from a M6.8 Wabash Valley earthquake centered 40 km northwest of the city produce ground motions that decrease with distance from 1.5 to 0.3 g for 0.2-s spectral acceleration when they reach the main part of Evansville, but then increase in amplitude from 0.3 to 0.6 g south of the city and the Ohio River. The densest urbanization in Evansville and Henderson, Ky., is within the area of preferential amplification at 1.0-s period for both scenarios, but the area

  7. Peak Wind Tool for General Forecasting

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III

    2010-01-01

    The expected peak wind speed of the day is an important forecast element in the 45th Weather Squadron's (45 WS) daily 24-Hour and Weekly Planning Forecasts. The forecasts are used for ground and space launch operations at the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45 WS also issues wind advisories for KSC/CCAFS when they expect wind gusts to meet or exceed 25 kt, 35 kt and 50 kt thresholds at any level from the surface to 300 ft. The 45 WS forecasters have indicated peak wind speeds are challenging to forecast, particularly in the cool season months of October - April. In Phase I of this task, the Applied Meteorology Unit (AMU) developed a tool to help the 45 WS forecast non-convective winds at KSC/CCAFS for the 24-hour period of 0800 to 0800 local time. The tool was delivered as a Microsoft Excel graphical user interface (GUI). The GUI displayed the forecast of peak wind speed, 5-minute average wind speed at the time of the peak wind, timing of the peak wind and probability the peak speed would meet or exceed 25 kt, 35 kt and 50 kt. For the current task (Phase II ), the 45 WS requested additional observations be used for the creation of the forecast equations by expanding the period of record (POR). Additional parameters were evaluated as predictors, including wind speeds between 500 ft and 3000 ft, static stability classification, Bulk Richardson Number, mixing depth, vertical wind shear, temperature inversion strength and depth and wind direction. Using a verification data set, the AMU compared the performance of the Phase I and II prediction methods. Just as in Phase I, the tool was delivered as a Microsoft Excel GUI. The 45 WS requested the tool also be available in the Meteorological Interactive Data Display System (MIDDS). The AMU first expanded the POR by two years by adding tower observations, surface observations and CCAFS (XMR) soundings for the cool season months of March 2007 to April 2009. The POR was expanded

  8. Ground Zero.

    ERIC Educational Resources Information Center

    Lozada, Marlene

    1998-01-01

    Many public school districts have adopted a policy of zero tolerance toward drug use, weapon possession, and sexual harassment on school grounds. Although a study by the National Center for Education Statistics reported no evidence that zero tolerance policies have lowered school crime rates, prominent education groups favor them. (JOW)

  9. An evaluation of the strong ground motion recorded during the May 1, 2003 Bingol Turkey, earthquake

    USGS Publications Warehouse

    Akkar, Sinan; Boore, David M.; Gulkan, Polat

    2005-01-01

    An important record of ground motion from a M6.4 earthquake occurring on May 1, 2003, at epicentral and fault distances of about 12 and 9 km, respectively, was obtained at a station near the city of Bingöl, Turkey. The maximum peak ground values of 0.55g and 36 cm/s are among the largest ground-motion amplitudes recorded in Turkey. From simulations and comparisons with ground motions from other earthquakes of comparable magnitude, we conclude that the ground motion over a range of frequencies is unusually high. Site response may be responsible for the elevated ground motion, as suggested from analysis of numerous aftershock recordings from the same station. The mainshock motions have some interesting seismological features, including ramps between the P- and S-wave that are probably due to near- and intermediate-field elastic motions and strong polarisation oriented at about 39 degrees to the fault (and therefore not in the fault-normal direction). Simulations of motions from an extended rupture explain these features. The N10E component shows a high-amplitude spectral acceleration at a period of 0.15 seconds resulting in a site specific design spectrum that significantly overestimates the actual strength and displacement demands of the record. The pulse signal in the N10E component affects the inelastic spectral displacement and increases the inelastic displacement demand with respect to elastic demand for very long periods.

  10. Oceanic Lightning versus Continental Lightning: VLF Peak Current Discrepancies

    NASA Astrophysics Data System (ADS)

    Dupree, N. A., Jr.; Moore, R. C.

    2015-12-01

    Recent analysis of the Vaisala global lightning data set GLD360 suggests that oceanic lightning tends to exhibit larger peak currents than continental lightning (lightning occurring over land). The GLD360 peak current measurement is derived from distant measurements of the electromagnetic fields emanated during the lightning flash. Because the GLD360 peak current measurement is a derived quantity, it is not clear whether the actual peak currents of oceanic lightning tend to be larger, or whether the resulting electromagnetic field strengths tend to be larger. In this paper, we present simulations of VLF signal propagation in the Earth-ionosphere waveguide to demonstrate that the peak field values for oceanic lightning can be significantly stronger than for continental lightning. Modeling simulations are performed using the Long Wave Propagation Capability (LWPC) code to directly evaluate the effect of ground conductivity on VLF signal propagation in the 5-15 kHz band. LWPC is an inherently narrowband propagation code that has been modified to predict the broadband response of the Earth-Ionosphere waveguide to an impulsive lightning flash while preserving the ability of LWPC to account for an inhomogeneous waveguide. Furthermore, we evaluate the effect of return stroke speed on these results.

  11. Peak Ring Craters and Multiring Basins

    NASA Astrophysics Data System (ADS)

    Melosh, H. J.

    2015-09-01

    Understanding of the mechanics of peak-ring crater and basin formation has expanded greatly due to the high precision data on lunar gravity from GRAIL. Peak rings coincide with the edges of underlying mantle uplifts on the Moon.

  12. Peak-flow characteristics of Virginia streams

    USGS Publications Warehouse

    Austin, Samuel H.; Krstolic, Jennifer L.; Wiegand, Ute

    2011-01-01

    Peak-flow annual exceedance probabilities, also called probability-percent chance flow estimates, and regional regression equations are provided describing the peak-flow characteristics of Virginia streams. Statistical methods are used to evaluate peak-flow data. Analysis of Virginia peak-flow data collected from 1895 through 2007 is summarized. Methods are provided for estimating unregulated peak flow of gaged and ungaged streams. Station peak-flow characteristics identified by fitting the logarithms of annual peak flows to a Log Pearson Type III frequency distribution yield annual exceedance probabilities of 0.5, 0.4292, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 for 476 streamgaging stations. Stream basin characteristics computed using spatial data and a geographic information system are used as explanatory variables in regional regression model equations for six physiographic regions to estimate regional annual exceedance probabilities at gaged and ungaged sites. Weighted peak-flow values that combine annual exceedance probabilities computed from gaging station data and from regional regression equations provide improved peak-flow estimates. Text, figures, and lists are provided summarizing selected peak-flow sites, delineated physiographic regions, peak-flow estimates, basin characteristics, regional regression model equations, error estimates, definitions, data sources, and candidate regression model equations. This study supersedes previous studies of peak flows in Virginia.

  13. Discourse Peak as Zone of Turbulence.

    ERIC Educational Resources Information Center

    Longacre, Robert E.

    Defining peak as the climax of discourse, this paper argues that it is important to identify peak in order to get at the overall grammar of a given discourse. The paper presents case studies in which four instances of peak in narrative discourses occur in languages from four different parts of the world. It also illustrates the occurrence of a…

  14. Particle acceleration in dipolarization events

    NASA Astrophysics Data System (ADS)

    Birn, J.; Hesse, M.; Nakamura, R.; Zaharia, S.

    2013-05-01

    Using the electromagnetic fields of a recent MHD simulation of magnetotail reconnection, flow bursts and dipolarization, we investigate the acceleration of test particles (protons and electrons) to suprathermal energies, confirming and extending earlier results on acceleration mechanisms and sources. (Part of the new results have been reviewed recently in Birn et al., Space Science Reviews, 167, doi:10.1007/ s11214-012-9874-4.) The test particle simulations reproduce major features of energetic particle events (injections) associated with substorms or other dipolarization events, particularly a rapid rise of energetic particle fluxes over limited ranges of energy. The major acceleration mechanisms for electrons are betatron acceleration and Fermi acceleration in the collapsing magnetic field. Ions, although non-adiabatic, undergo similar acceleration. Two major entry mechanisms into the acceleration site are identified: cross-tail drift from the inner tail plasma sheet and reconnection entry from field lines extending to the more distant plasma sheet. The former dominates early in an event and at higher energies (hundreds of keV) while the latter constitutes the main source later and at lower energies (tens of keV). Despite the fact that the injection front moves earthward in the tail, the peak of energetic particle fluxes moves to higher latitude when mapped from the near-Earth boundary to Earth in a static magnetic field model.

  15. Pre-Peak and Post-Peak Rock Strain Characteristics During Uniaxial Compression by 3D Digital Image Correlation

    NASA Astrophysics Data System (ADS)

    Munoz, H.; Taheri, A.; Chanda, E. K.

    2016-07-01

    A non-contact optical method for strain measurement applying three-dimensional digital image correlation (3D DIC) in uniaxial compression is presented. A series of monotonic uniaxial compression tests under quasi-static loading conditions on Hawkesbury sandstone specimens were conducted. A prescribed constant lateral-strain rate to control the applied axial load in a closed-loop system allowed capturing the complete stress-strain behaviour of the rock, i.e. the pre-peak and post-peak stress-strain regimes. 3D DIC uses two digital cameras to acquire images of the undeformed and deformed shape of an object to perform image analysis and provides deformation and motion measurements. Observations showed that 3D DIC provides strains free from bedding error in contrast to strains from LVDT. Erroneous measurements due to the compliance of the compressive machine are also eliminated. Furthermore, by 3D DIC technique relatively large strains developed in the post-peak regime, in particular within localised zones, difficult to capture by bonded strain gauges, can be measured in a straight forward manner. Field of strains and eventual strain localisation in the rock surface were analysed by 3D DIC method, coupled with the respective stress levels in the rock. Field strain development in the rock samples, both in axial and shear strain domains suggested that strain localisation takes place progressively and develops at a lower rate in pre-peak regime. It is accelerated, otherwise, in post-peak regime associated with the increasing rate of strength degradation. The results show that a major failure plane, due to strain localisation, becomes noticeable only long after the peak stress took place. In addition, post-peak stress-strain behaviour was observed to be either in a form of localised strain in a shearing zone or inelastic unloading outside of the shearing zone.

  16. VLHC accelerator physics

    SciTech Connect

    Michael Blaskiewicz et al.

    2001-11-01

    A six-month design study for a future high energy hadron collider was initiated by the Fermilab director in October 2000. The request was to study a staged approach where a large circumference tunnel is built that initially would house a low field ({approx}2 T) collider with center-of-mass energy greater than 30 TeV and a peak (initial) luminosity of 10{sup 34} cm{sup -2}s{sup -1}. The tunnel was to be scoped, however, to support a future upgrade to a center-of-mass energy greater than 150 TeV with a peak luminosity of 2 x 10{sup 34} cm{sup -2} sec{sup -1} using high field ({approx} 10 T) superconducting magnet technology. In a collaboration with Brookhaven National Laboratory and Lawrence Berkeley National Laboratory, a report of the Design Study was produced by Fermilab in June 2001. 1 The Design Study focused on a Stage 1, 20 x 20 TeV collider using a 2-in-1 transmission line magnet and leads to a Stage 2, 87.5 x 87.5 TeV collider using 10 T Nb{sub 3}Sn magnet technology. The article that follows is a compilation of accelerator physics designs and computational results which contributed to the Design Study. Many of the parameters found in this report evolved during the study, and thus slight differences between this text and the Design Study report can be found. The present text, however, presents the major accelerator physics issues of the Very Large Hadron Collider as examined by the Design Study collaboration and provides a basis for discussion and further studies of VLHC accelerator parameters and design philosophies.

  17. Berkeley Proton Linear Accelerator

    DOE R&D Accomplishments Database

    Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

    1953-10-13

    A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

  18. Ground motion observations of the South Napa earthquake (M6.0 August 24, 2014)

    NASA Astrophysics Data System (ADS)

    Baltay, A.

    2014-12-01

    The South Napa earthquake generated peak ground motions in excess of 50%g and 50 cm/s in Napa Valley and also along strike to the south, and was recorded at 17 stations within 20 km rupture distance (Rrup) of the finite fault plane, 115 stations within 50 km, and 246 within 100 km. We compare the densely recorded ground motions to existing ground motion prediction equations (GMPEs) to understand both the spatial distribution of ground-motion amplitudes and also the relative excitation and attenuation terms from the earthquake. Using the ground-motion data as reported by ShakeMap, we examine the peak ground acceleration (PGA) and velocity, as well as the pseudo-spectral acceleration (PSA) at 0.3, 1.0 and 3.0 seconds, adjusted empirically to a single site condition of 760 m/s. Overall, the ground motions on the north-south components are larger than those on the east-west, consistent with both the generally north-south strike of the fault and the rupture directivity. At the higher frequencies (PGA and PSA of 0.3 s), the close data are very consistent with the GMPEs, implying a median stress drop near 5 MPa. For the longer period data, the GMPEs underpredict the data at close stations. At all frequencies, the distance attenuation seems to be stronger than the GMPEs would predict, which could either be a station coverage bias, given that most of the stations are to the south of the epicenter, or may indicate that the attenuation structure in the Napa and delta region is stronger than the average attenuation in California, on which the GMPEs were built. The spatial plot of the ground motion residuals is positive to the north, in both Napa and Sonoma Valley, consistent with both the directivity and basin effect. More interestingly, perhaps, is that there is strong ground motion to the south, as well, in the along-strike direction, particularly for PSA at 1.0s. These strongly positive residuals align along an older, Quaternary fault structure associated with the Franklin

  19. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  20. Amplitude-dependent orbital period in alternating gradient accelerators

    NASA Astrophysics Data System (ADS)

    Machida, S.; Kelliher, D. J.; Edmonds, C. S.; Kirkman, I. W.; Berg, J. S.; Jones, J. K.; Muratori, B. D.; Garland, J. M.

    2016-03-01

    Orbital period in a ring accelerator and time of flight in a linear accelerator depend on the amplitude of betatron oscillations. The variation is negligible in ordinary particle accelerators with relatively small beam emittance. In an accelerator for large emittance beams like muons and unstable nuclei, however, this effect cannot be ignored. We measured orbital period in a linear non-scaling fixed-field alternating-gradient accelerator, which is a candidate for muon acceleration, and compared it with the theoretical prediction. The good agreement between them gives important ground for the design of particle accelerators for a new generation of particle and nuclear physics experiments.

  1. Technology of magnetically driven accelerators

    SciTech Connect

    Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Rogers, D. Jr.; Smith, M.W.

    1985-03-26

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability. 8 figs., 1 tab.

  2. Technology of magnetically driven accelerators

    SciTech Connect

    Brix, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

    1985-10-01

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability.

  3. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  4. Near field ground motion variability in kinematic simulations of the 1992 Landers earthquake

    NASA Astrophysics Data System (ADS)

    Vyas, Jagdish Chandra; Galis, Martin; Mai, Paul Martin

    2014-05-01

    We investigate near field ground motion variability due to five different kinematic rupture models inverted from observed data for 1992 Landers earthquake. The ground motion simulations are accomplished by solving the elastic equation of motion using a generalized finite-difference method (Ely et al., 2008) that handles geometric complexity of the fault, 3D variations in the medium as well as topography. Simulated waveforms are calibrated against near-field strong-motion recordings. We then analyze a large data-set of ground-motions computed at 2000 sites, binned with respect to distance and azimuth to compute mean and standard deviation of peak ground velocity (PGV) and pseudo spectral acceleration (PSA) for all five source models. We consider 1D-velocity structures as used in the source inversions, and honor the geometrical complexity due to segmentation of the rupture models. Our simulations reveal that ground motion variability is reduced as the distance from the fault increases. Variability in the kinematic sources has considerable impact on the resulting shaking variability, although the five source models considered are derived by inversion of seismic and/or geodetic data. Simulated mean PSA and its standard deviation are larger compared to empirical estimates using the ground-motion prediction equation (GMPE) of Boore and Atkinson (2008), whereas simulated PGV are comparable to GMPE estimates. In addition, we find that intra-event ground motion variability is large both in forward and backward directivity region, strongest in the backward region, and smallest in the fault perpendicular direction. We then examine ground-motion variability with respect to directivity effects, due to a combination of rupture propagation and radiation pattern. The comparison of our simulations with and without Spudich and Chiou (2008) directivity corrections to Boore and Atkinson (2008) predictions indicates that slip heterogeneity is the key contributor to ground motion

  5. Dynamic modeling of injection-induced fault reactivation and ground motion and impact on surface structures and human perception

    SciTech Connect

    Rutqvist, Jonny; Cappa, Frederic; Rinaldi, Antonio P.; Godano, Maxime

    2014-12-31

    We summarize recent modeling studies of injection-induced fault reactivation, seismicity, and its potential impact on surface structures and nuisance to the local human population. We used coupled multiphase fluid flow and geomechanical numerical modeling, dynamic wave propagation modeling, seismology theories, and empirical vibration criteria from mining and construction industries. We first simulated injection-induced fault reactivation, including dynamic fault slip, seismic source, wave propagation, and ground vibrations. From co-seismic average shear displacement and rupture area, we determined the moment magnitude to about Mw = 3 for an injection-induced fault reactivation at a depth of about 1000 m. We then analyzed the ground vibration results in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and frequency content, with comparison to the U.S. Bureau of Mines’ vibration criteria for cosmetic damage to buildings, as well as human-perception vibration limits. For the considered synthetic Mw = 3 event, our analysis showed that the short duration, high frequency ground motion may not cause any significant damage to surface structures, and would not cause, in this particular case, upward CO2 leakage, but would certainly be felt by the local population.

  6. Dynamic modeling of injection-induced fault reactivation and ground motion and impact on surface structures and human perception

    DOE PAGESBeta

    Rutqvist, Jonny; Cappa, Frederic; Rinaldi, Antonio P.; Godano, Maxime

    2014-12-31

    We summarize recent modeling studies of injection-induced fault reactivation, seismicity, and its potential impact on surface structures and nuisance to the local human population. We used coupled multiphase fluid flow and geomechanical numerical modeling, dynamic wave propagation modeling, seismology theories, and empirical vibration criteria from mining and construction industries. We first simulated injection-induced fault reactivation, including dynamic fault slip, seismic source, wave propagation, and ground vibrations. From co-seismic average shear displacement and rupture area, we determined the moment magnitude to about Mw = 3 for an injection-induced fault reactivation at a depth of about 1000 m. We then analyzed themore » ground vibration results in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and frequency content, with comparison to the U.S. Bureau of Mines’ vibration criteria for cosmetic damage to buildings, as well as human-perception vibration limits. For the considered synthetic Mw = 3 event, our analysis showed that the short duration, high frequency ground motion may not cause any significant damage to surface structures, and would not cause, in this particular case, upward CO2 leakage, but would certainly be felt by the local population.« less

  7. On the trail of double peak hydrographs

    NASA Astrophysics Data System (ADS)

    Martínez-Carreras, Núria; Hissler, Christophe; Gourdol, Laurent; Klaus, Julian; Juilleret, Jérôme; François Iffly, Jean; McDonnell, Jeffrey J.; Pfister, Laurent

    2016-04-01

    A double peak hydrograph features two peaks as a response to a unique rainfall pulse. The first peak occurs at the same time or shortly after the precipitation has started and it corresponds to a fast catchment response to precipitation. The delayed peak normally starts during the recession of the first peak, when the precipitation has already ceased. Double peak hydrographs may occur for various reasons. They can occur (i) in large catchments when lag times in tributary responses are large, (ii) in urban catchments where the first peak is often caused by direct surface runoff on impervious land cover, and the delayed peak to slower subsurface flow, and (iii) in non-urban catchments, where the first and the delayed discharge peaks are explained by different runoff mechanisms (e.g. overland flow, subsurface flow and/or deep groundwater flow) that have different response times. Here we focus on the third case, as a formal description of the different hydrological mechanisms explaining these complex hydrological dynamics across catchments with diverse physiographic characteristics is still needed. Based on a review of studies documenting double peak events we have established a formal classification of catchments presenting double peak events based on their regolith structure (geological substratum and/or its weathered products). We describe the different hydrological mechanisms that trigger these complex hydrological dynamics across each catchment type. We then use hydrometric time series of precipitation, runoff, soil moisture and groundwater levels collected in the Weierbach (0.46 km2) headwater catchment (Luxembourg) to better understand double peak hydrograph generation. Specifically, we aim to find out (1) if the generation of a double peak hydrograph is a threshold process, (2) if the hysteretic relationships between storage and discharge are consistent during single and double peak hydrographs, and (3) if different functional landscape units (the hillslopes

  8. Investigation of advanced propulsion technologies: The RAM accelerator and the flowing gas radiation heater

    NASA Technical Reports Server (NTRS)

    Bruckner, A. P.; Knowlen, C.; Mattick, A. T.; Hertzberg, A.

    1992-01-01

    The two principal areas of advanced propulsion investigated are the ram accelerator and the flowing gas radiation heater. The concept of the ram accelerator is presented as a hypervelocity launcher for large-scale aeroballistic range applications in hypersonics and aerothermodynamics research. The ram accelerator is an in-bore ramjet device in which a projectile shaped like the centerbody of a supersonic ramjet is propelled in a stationary tube filled with a tailored combustible gas mixture. Combustion on and behind the projectile generates thrust which accelerates it to very high velocities. The acceleration can be tailored for the 'soft launch' of instrumented models. The distinctive reacting flow phenomena that have been observed in the ram accelerator are relevant to the aerothermodynamic processes in airbreathing hypersonic propulsion systems and are useful for validating sophisticated CFD codes. The recently demonstrated scalability of the device and the ability to control the rate of acceleration offer unique opportunities for the use of the ram accelerator as a large-scale hypersonic ground test facility. The flowing gas radiation receiver is a novel concept for using solar energy to heat a working fluid for space power or propulsion. Focused solar radiation is absorbed directly in a working gas, rather than by heat transfer through a solid surface. Previous theoretical analysis had demonstrated that radiation trapping reduces energy loss compared to that of blackbody receivers, and enables higher efficiencies and higher peak temperatures. An experiment was carried out to measure the temperature profile of an infrared-active gas and demonstrate the effect of radiation trapping. The success of this effort validates analytical models of heat transfer in this receiver, and confirms the potential of this approach for achieving high efficiency space power and propulsion.

  9. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  10. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  11. Rupture dynamics and ground motions from earthquakes in 2-D heterogeneous media

    NASA Astrophysics Data System (ADS)

    Bydlon, Samuel A.; Dunham, Eric M.

    2015-03-01

    We perform 2-D simulations of earthquakes on rough faults in media with random heterogeneities (with von Karman distribution) to study the effects of geometric and material heterogeneity on the rupture process and resulting high-frequency ground motions in the near-fault region (out to ˜20 km). Variations in slip and rupture velocity can arise from material heterogeneity alone but are dominantly controlled by fault roughness. Scattering effects become appreciable beyond ˜3 km from the fault. Near-fault scattering extends the duration of incoherent, high-frequency ground motions and, at least in our 2-D simulations, elevates root-mean-square accelerations (i.e., Arias intensity) with negligible reduction in peak velocities. We also demonstrate that near-fault scattering typically occurs in the power law tail of the power spectral density function, quantified by the Hurst exponent and another parameter combining standard deviation and correlation length.

  12. Transonic and supersonic ground effect aerodynamics

    NASA Astrophysics Data System (ADS)

    Doig, G.

    2014-08-01

    A review of recent and historical work in the field of transonic and supersonic ground effect aerodynamics has been conducted, focussing on applied research on wings and aircraft, present and future ground transportation, projectiles, rocket sleds and other related bodies which travel in close ground proximity in the compressible regime. Methods for ground testing are described and evaluated, noting that wind tunnel testing is best performed with a symmetry model in the absence of a moving ground; sled or rail testing is ultimately preferable, though considerably more expensive. Findings are reported on shock-related ground influence on aerodynamic forces and moments in and accelerating through the transonic regime - where force reversals and the early onset of local supersonic flow is prevalent - as well as more predictable behaviours in fully supersonic to hypersonic ground effect flows.

  13. Microcomputer-based Acceleration Sensor Device for Swimming Stroke Monitoring

    NASA Astrophysics Data System (ADS)

    Ohgi, Yuji; Ichikawa, Hiroshi; Miyaji, Chikara

    The purpose of this study was to develop a microcomputer-based acceleration logger device for the swimming stroke monitoring. The authors measured the swimmer's tri-axial wrist acceleration and applied this device for the fatigue evaluation of the swimmers. The experimental protocol led the swimmers exhausted after the crawl stroke interval training. Every single stroke was determined by the impact acceleration peak, which appeared on the x and z-axis acceleration. The change of the underwater stroke phases was identified by the characteristics of the acceleration peaks. In their exhaustion, the y-axis acceleration, which was longitudinal forearm acceleration decreased at the beginning of the upsweep phase. At that time, the swimmer could not extend his elbow joint. Since the developed acceleration data logger could provide us the information about the underwater stroke phases and it would be a helpful tool in the swimming training.

  14. Passive radio frequency peak power multiplier

    DOEpatents

    Farkas, Zoltan D.; Wilson, Perry B.

    1977-01-01

    Peak power multiplication of a radio frequency source by simultaneous charging of two high-Q resonant microwave cavities by applying the source output through a directional coupler to the cavities and then reversing the phase of the source power to the coupler, thereby permitting the power in the cavities to simultaneously discharge through the coupler to the load in combination with power from the source to apply a peak power to the load that is a multiplication of the source peak power.

  15. Light pressure acceleration with frequency-tripled laser pulse

    SciTech Connect

    Wang, Xiaofeng; Shen, Baifei E-mail: zhxm@siom.ac.cn; Zhang, Xiaomei E-mail: zhxm@siom.ac.cn; Ji, Liangliang; Wang, Wenpeng; Zhao, Xueyan; Xu, Jiancai; Yu, Yahong; Yi, Longqing; Shi, Yin; Xu, Tongjun; Zhang, Lingang

    2014-08-15

    Light pressure acceleration of ions in the interaction of the frequency-tripled (3ω) laser pulse and foil target is studied, and a promising method to increase accelerated ion energy is shown. Results show that at a constant laser energy, much higher ion energy peak value is obtained for 3ω laser compared with that using the fundamental frequency laser. The effect of energy loss during frequency conversion on ion acceleration is considered, which may slightly decrease the acceleration effect.

  16. The Pulse Line Ion Accelerator Concept

    SciTech Connect

    Briggs, Richard J.

    2006-02-15

    The Pulse Line Ion Accelerator concept was motivated by the desire for an inexpensive way to accelerate intense short pulse heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. A pulse power driver applied at one end of a helical pulse line creates a traveling wave pulse that accelerates and axially confines the heavy ion beam pulse. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/meter acceleration gradients. The concept might be described crudely as an ''air core'' induction linac where the PFN is integrated into the beam line so the accelerating voltage pulse can move along with the ions to get voltage multiplication.

  17. Analysis of ground response data at Lotung large-scale soil- structure interaction experiment site

    SciTech Connect

    Chang, C.Y.; Mok, C.M.; Power, M.S. )

    1991-12-01

    The Electric Power Research Institute (EPRI), in cooperation with the Taiwan Power Company (TPC), constructed two models (1/4-scale and 1/2-scale) of a nuclear plant containment structure at a site in Lotung (Tang, 1987), a seismically active region in northeast Taiwan. The models were constructed to gather data for the evaluation and validation of soil-structure interaction (SSI) analysis methodologies. Extensive instrumentation was deployed to record both structural and ground responses at the site during earthquakes. The experiment is generally referred to as the Lotung Large-Scale Seismic Test (LSST). As part of the LSST, two downhole arrays were installed at the site to record ground motions at depths as well as at the ground surface. Structural response and ground response have been recorded for a number of earthquakes (i.e. a total of 18 earthquakes in the period of October 1985 through November 1986) at the LSST site since the completion of the installation of the downhole instruments in October 1985. These data include those from earthquakes having magnitudes ranging from M{sub L} 4.5 to M{sub L} 7.0 and epicentral distances range from 4.7 km to 77.7 km. Peak ground surface accelerations range from 0.03 g to 0.21 g for the horizontal component and from 0.01 g to 0.20 g for the vertical component. The objectives of the study were: (1) to obtain empirical data on variations of earthquake ground motion with depth; (2) to examine field evidence of nonlinear soil response due to earthquake shaking and to determine the degree of soil nonlinearity; (3) to assess the ability of ground response analysis techniques including techniques to approximate nonlinear soil response to estimate ground motions due to earthquake shaking; and (4) to analyze earth pressures recorded beneath the basemat and on the side wall of the 1/4 scale model structure during selected earthquakes.

  18. Effects of Ground Motion Input on the Derived Fragility Functions: Case study of 2010 Haiti Earthquake

    NASA Astrophysics Data System (ADS)

    Hancilar, Ufuk; Harmandar, Ebru; Çakti, Eser

    2014-05-01

    Empirical fragility functions are derived by statistical processing of the data on: i) Damaged and undamaged buildings, and ii) Ground motion intensity values at the buildings' locations. This study investigates effects of different ground motion inputs on the derived fragility functions. The previously constructed fragility curves (Hancilar et al. 2013), which rely on specific shaking intensity maps published by the USGS after the 2010 Haiti Earthquake, are compared with the fragility functions computed in the present study. Building data come from field surveys of 6,347 buildings that are grouped with respect to structural material type and number of stories. For damage assessment, the European Macroseismic Scale (EMS-98) damage grades are adopted. The simplest way to account for the variability in ground motion input could have been achieved by employing different ground motion prediction equations (GMPEs) and their standard variations. However, in this work, we prefer to rely on stochastically simulated ground motions of the Haiti earthquake. We employ five different source models available in the literature and calculate the resulting strong ground motion in time domain. In our simulations we also consider the local site effects by published studies on NEHRP site classes and micro-zoning maps of the city of Port-au-Prince. We estimate the regional distributions from the waveforms simulated at the same coordinates that we have damage information from. The estimated spatial distributions of peak ground accelerations and velocities, PGA and PGV respectively, are then used as input to fragility computations. The results show that changing the ground motion input causes significant variability in the resulting fragility functions.

  19. IMPULSIVE ACCELERATION OF CORONAL MASS EJECTIONS. I. STATISTICS AND CORONAL MASS EJECTION SOURCE REGION CHARACTERISTICS

    SciTech Connect

    Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M.; Muhr, N.; Kienreich, I.; Utz, D.

    2011-09-10

    We use high time cadence images acquired by the STEREO EUVI and COR instruments to study the evolution of coronal mass ejections (CMEs) from their initiation through impulsive acceleration to the propagation phase. For a set of 95 CMEs we derived detailed height, velocity, and acceleration profiles and statistically analyzed characteristic CME parameters: peak acceleration, peak velocity, acceleration duration, initiation height, height at peak velocity, height at peak acceleration, and size of the CME source region. The CME peak accelerations we derived range from 20 to 6800 m s{sup -2} and are inversely correlated with the acceleration duration and the height at peak acceleration. Seventy-four percent of the events reach their peak acceleration at heights below 0.5 R{sub sun}. CMEs that originate from compact sources low in the corona are more impulsive and reach higher peak accelerations at smaller heights. These findings can be explained by the Lorentz force, which drives the CME accelerations and decreases with height and CME size.

  20. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  1. The green leafhopper, Cicadella viridis (Hemiptera, Auchenorrhyncha, Cicadellidae), jumps with near-constant acceleration.

    PubMed

    Bonsignori, Gabriella; Stefanini, Cesare; Scarfogliero, Umberto; Mintchev, Stefano; Benelli, Giovanni; Dario, Paolo

    2013-04-01

    Jumping insects develop accelerations that can greatly exceed gravitational acceleration. Although several species have been analysed using different tools, ranging from a purely physical to a morpho-physiological approach, instantaneous dynamic and kinematic data concerning the jumping motion are lacking. This is mainly due to the difficulty in observing in detail events that occur in a few milliseconds. In this study, the behaviour of the green leafhopper, Cicadella viridis, was investigated during the take-off phase of the jump, through high-speed video recordings (8000 frames s(-1)). We demonstrate that C. viridis is able to maintain fairly constant acceleration during overall leg elongation. The force exerted at the foot-ground interface is nearly constant and differs from the force expected from other typical motion models. A biomechanical model was used to highlight that this ability relies on the morphology of C. viridis hind legs, which act as a motion converter with a variable transmission ratio and use the time-dependent musculo-elastic force to generate a nearly constant thrust at the body-ground interface. This modulation mechanism minimizes the risk of breaking the substrate thanks to the absence of force peaks. The results of this study are of broad relevance in different research fields ranging from biomechanics to robotics. PMID:23487271

  2. The Boson peak in supercooled water.

    PubMed

    Kumar, Pradeep; Wikfeldt, K Thor; Schlesinger, Daniel; Pettersson, Lars G M; Stanley, H Eugene

    2013-01-01

    We perform extensive molecular dynamics simulations of the TIP4P/2005 model of water to investigate the origin of the Boson peak reported in experiments on supercooled water in nanoconfined pores, and in hydration water around proteins. We find that the onset of the Boson peak in supercooled bulk water coincides with the crossover to a predominantly low-density-like liquid below the Widom line TW. The frequency and onset temperature of the Boson peak in our simulations of bulk water agree well with the results from experiments on nanoconfined water. Our results suggest that the Boson peak in water is not an exclusive effect of confinement. We further find that, similar to other glass-forming liquids, the vibrational modes corresponding to the Boson peak are spatially extended and are related to transverse phonons found in the parent crystal, here ice Ih. PMID:23771033

  3. Weld peaking on heavy aluminum structures

    NASA Technical Reports Server (NTRS)

    Bayless, E.; Poorman, R.; Sexton, J.

    1978-01-01

    Weld peaking is usually undesirable in any welded structure. In heavy structures, the forces involved in the welding process become very large and difficult to handle. With the shuttle's solid rocket booster, the weld peaking resulted in two major problems: (1) reduced mechanical properties across the weld joint, and (2) fit-up difficulties in subsequent assembly operation. Peaking from the weld shrinkage forces can be fairly well predicted in simple structures; however, in welding complicated assemblies, the amount of peaking is unpredictable because of unknown stresses from machining and forming, stresses induced by the fixturing, and stresses from welds in other parts of the assembly. When excessive peaking is encountered, it can be corrected using the shrinkage forces resulting from the welding process. Application of these forces is discussed in this report.

  4. Strong ground motion in the Taipei basin from the 1999 Chi-Chi, Taiwan, earthquake

    USGS Publications Warehouse

    Fletcher, Joe B.; Wen, K.-L.

    2005-01-01

    The Taipei basin, located in northwest Taiwan about 160 km from the epicenter of the Chi-Chi earthquake, is a shallow, triangular-shaped basin filled with low-velocity fluvial deposits. There is a strong velocity contrast across the basement interface of about 600 m/sec at a depth of about 600-700 m in the deeper section of the basin, suggesting that ground motion should be amplified at sites in the basin. In this article, the ground-motion recordings are analyzed to determine the effect of the basin both in terms of amplifications expected from a 1D model of the sediments in the basin and in terms of the 3D structure of the basin. Residuals determined for peak acceleration from attenuation curves are more positive (amplified) in the basin (average of 5.3 cm/ sec2 compared to - 24.2 cm/sec2 for those stations outside the basin and between 75 and 110 km from the surface projection of the faulted area, a 40% increase in peak ground acceleration). Residuals for peak velocity are also significantly more positive at stations in the basin (31.8 cm/sec compared to 20.0 cm/sec out). The correlation of peak motion with depth to basement, while minor in peak acceleration, is stronger in the peak velocities. Record sections of ground motion from stations in and around the Taipei basin show that the largest long-period arrival, which is coherent across the region, is strongest on the vertical component and has a period of about 10-12 sec. This phase appears to be a Rayleigh wave, probably associated with rupture at the north end of the Chelungpu fault. Records of strong motion from stations in and near the basin have an additional, higher frequency signal: nearest the deepest point in the basin, the signal is characterized by frequencies of about 0.3 - 0.4 Hz. These frequencies are close to simple predictions using horizontal layers and the velocity structure of the basin. Polarizations of the S wave are mostly coherent across the array, although there are significant

  5. Multiscale peak detection in wavelet space.

    PubMed

    Zhang, Zhi-Min; Tong, Xia; Peng, Ying; Ma, Pan; Zhang, Ming-Jin; Lu, Hong-Mei; Chen, Xiao-Qing; Liang, Yi-Zeng

    2015-12-01

    Accurate peak detection is essential for analyzing high-throughput datasets generated by analytical instruments. Derivatives with noise reduction and matched filtration are frequently used, but they are sensitive to baseline variations, random noise and deviations in the peak shape. A continuous wavelet transform (CWT)-based method is more practical and popular in this situation, which can increase the accuracy and reliability by identifying peaks across scales in wavelet space and implicitly removing noise as well as the baseline. However, its computational load is relatively high and the estimated features of peaks may not be accurate in the case of peaks that are overlapping, dense or weak. In this study, we present multi-scale peak detection (MSPD) by taking full advantage of additional information in wavelet space including ridges, valleys, and zero-crossings. It can achieve a high accuracy by thresholding each detected peak with the maximum of its ridge. It has been comprehensively evaluated with MALDI-TOF spectra in proteomics, the CAMDA 2006 SELDI dataset as well as the Romanian database of Raman spectra, which is particularly suitable for detecting peaks in high-throughput analytical signals. Receiver operating characteristic (ROC) curves show that MSPD can detect more true peaks while keeping the false discovery rate lower than MassSpecWavelet and MALDIquant methods. Superior results in Raman spectra suggest that MSPD seems to be a more universal method for peak detection. MSPD has been designed and implemented efficiently in Python and Cython. It is available as an open source package at . PMID:26514234

  6. Muscle contributions to fore-aft and vertical body mass center accelerations over a range of running speeds.

    PubMed

    Hamner, Samuel R; Delp, Scott L

    2013-02-22

    Running is a bouncing gait in which the body mass center slows and lowers during the first half of the stance phase; the mass center is then accelerated forward and upward into flight during the second half of the stance phase. Muscle-driven simulations can be analyzed to determine how muscle forces accelerate the body mass center. However, muscle-driven simulations of running at different speeds have not been previously developed, and it remains unclear how muscle forces modulate mass center accelerations at different running speeds. Thus, to examine how muscles generate accelerations of the body mass center, we created three-dimensional muscle-driven simulations of ten subjects running at 2.0, 3.0, 4.0, and 5.0m/s. An induced acceleration analysis determined the contribution of each muscle to mass center accelerations. Our simulations included arms, allowing us to investigate the contributions of arm motion to running dynamics. Analysis of the simulations revealed that soleus provides the greatest upward mass center acceleration at all running speeds; soleus generates a peak upward acceleration of 19.8m/s(2) (i.e., the equivalent of approximately 2.0 bodyweights of ground reaction force) at 5.0m/s. Soleus also provided the greatest contribution to forward mass center acceleration, which increased from 2.5m/s(2) at 2.0m/s to 4.0m/s(2) at 5.0m/s. At faster running speeds, greater velocity of the legs produced larger angular momentum about the vertical axis passing through the body mass center; angular momentum about this vertical axis from arm swing simultaneously increased to counterbalance the legs. We provide open-access to data and simulations from this study for further analysis in OpenSim at simtk.org/home/nmbl_running, enabling muscle actions during running to be studied in unprecedented detail. PMID:23246045

  7. Effects of Different Lifting Cadences on Ground Reaction Forces during the Squat Exercise

    NASA Technical Reports Server (NTRS)

    Bentley, Jason R.; Amonette, William E.; Hagan, R. Donald

    2008-01-01

    The purpose of this investigation was to determine the effect of different cadences on the ground reaction force (GRF(sub R)) during the squat exercise. It is known that squats performed with greater acceleration will produce greater inertial forces; however, it is not well understood how different squat cadences affect GRF(sub R). It was hypothesized that faster squat cadences will result in greater peak GRF(sub R). METHODS: Six male subjects (30.8+/-4.4 y, 179.5+/-8.9 cm, 88.8+/-13.3 kg) with previous squat experience performed three sets of three squats using three different cadences (FC = 1 sec descent/1 sec ascent; MC = 3 sec descent/1 sec ascent; SC = 4 sec descent/2 sec ascent) with barbell mass equal to body mass. Ground reaction force was used to calculate inertial force trajectories of the body plus barbell (FI(sub system)). Forces were normalized to body mass. RESULTS: Peak GRF(sub R) and peak FI(sub system) were significantly higher in FC squats compared to MC (p=0.0002) and SC (p=0.0002). Range of GRF(sub R) and FI(sub system) were also significantly higher in FC compared to MC (p<0.05), and MC were significantly higher than SC (p<0.05). DISCUSSION: Faster squat cadences result in significantly greater peak GRF(sub R) due to the inertia of the system. GRF(sub R) was more dependent upon decent cadence than on ascent cadence. PRACTICAL APPLICATION: This study demonstrates that faster squat cadences produce greater ground reaction forces. Therefore, the use of faster squat cadences might enhance strength and power adaptations to long-term resistance exercise training. Key Words: velocity, weight training, resistive exercise

  8. PeakRanger: A cloud-enabled peak caller for ChIP-seq data

    PubMed Central

    2011-01-01

    Background Chromatin immunoprecipitation (ChIP), coupled with massively parallel short-read sequencing (seq) is used to probe chromatin dynamics. Although there are many algorithms to call peaks from ChIP-seq datasets, most are tuned either to handle punctate sites, such as transcriptional factor binding sites, or broad regions, such as histone modification marks; few can do both. Other algorithms are limited in their configurability, performance on large data sets, and ability to distinguish closely-spaced peaks. Results In this paper, we introduce PeakRanger, a peak caller software package that works equally well on punctate and broad sites, can resolve closely-spaced peaks, has excellent performance, and is easily customized. In addition, PeakRanger can be run in a parallel cloud computing environment to obtain extremely high performance on very large data sets. We present a series of benchmarks to evaluate PeakRanger against 10 other peak callers, and demonstrate the performance of PeakRanger on both real and synthetic data sets. We also present real world usages of PeakRanger, including peak-calling in the modENCODE project. Conclusions Compared to other peak callers tested, PeakRanger offers improved resolution in distinguishing extremely closely-spaced peaks. PeakRanger has above-average spatial accuracy in terms of identifying the precise location of binding events. PeakRanger also has excellent sensitivity and specificity in all benchmarks evaluated. In addition, PeakRanger offers significant improvements in run time when running on a single processor system, and very marked improvements when allowed to take advantage of the MapReduce parallel environment offered by a cloud computing resource. PeakRanger can be downloaded at the official site of modENCODE project: http://www.modencode.org/software/ranger/ PMID:21554709

  9. Quiet Spike (TM) Build-Up Ground Vibration Testing Approach

    NASA Technical Reports Server (NTRS)

    Spivey, Natalie D.; Herrera, Claudia; Truax, Roger; Pak, Chan-gi; Freund, Donald

    2007-01-01

    Flight tests of Gulfstream Aerospace Corporation s Quiet Spike(TM) hardware were recently completed on the NASA Dryden Flight Research Center F-15B airplane. NASA Dryden uses a modified F-15B airplane as a testbed aircraft to cost-effectively fly flight research experiments that are typically mounted underneath the F-15B airplane, along the fuselage centerline. For the Quiet Spike(TM) experiment, however, instead of a centerline mounting, a relatively long forward-pointing boom was attached to the radar bulkhead of the F-15B airplane. The Quiet Spike(TM) experiment is a stepping-stone to airframe structural morphing technologies designed to mitigate the sonic-boom strength of business jets over land. The Quiet Spike(TM) boom is a concept in which an aircraft's noseboom would be extended prior to supersonic acceleration. This morphing effectively lengthens the aircraft, thus reducing the peak sonic-boom amplitude, but is also expected to partition the otherwise strong bow shock into a series of reduced-strength, noncoalescing shocklets. Prior to flying the Quiet Spike(TM) experiment on the F-15B airplane several ground vibration tests were required to understand the Quiet Spike(TM) modal characteristics and coupling effects with the F-15B airplane. However, due to the flight hardware availability and compressed schedule requirements, a "traditional" ground vibration test of the mated F-15B Quiet Spike(TM) ready-for-flight configuration did not leave sufficient time available for the finite element model update and flutter analyses before flight testing. Therefore, a "nontraditional" ground vibration testing approach was taken. This paper provides an overview of each phase of the "nontraditional" ground vibration testing completed for the Quiet Spike(TM) project which includes the test setup details, instrumentation layout, and modal results obtained in support of the structural dynamic modeling and flutter analyses.

  10. Peaks theory and the excursion set approach

    NASA Astrophysics Data System (ADS)

    Paranjape, Aseem; Sheth, Ravi K.

    2012-11-01

    We describe a model of dark matter halo abundances and clustering which combines the two most widely used approaches to this problem: that based on peaks and the other based on excursion sets. Our approach can be thought of as addressing the cloud-in-cloud problem for peaks and/or modifying the excursion set approach so that it averages over a special subset, rather than all possible walks. In this respect, it seeks to account for correlations between steps in the walk as well as correlations between walks. We first show how the excursion set and peaks models can be written in the same formalism, and then use this correspondence to write our combined excursion set peaks model. We then give simple expressions for the mass function and bias, showing that even the linear halo bias factor is predicted to be k-dependent as a consequence of the non-locality associated with the peak constraint. At large masses, our model has little or no need to rescale the variable δc from the value associated with spherical collapse, and suggests a simple explanation for why the linear halo bias factor appears to lie above that based on the peak-background split at high masses when such a rescaling is assumed. Although we have concentrated on peaks, our analysis is more generally applicable to other traditionally single-scale analyses of large-scale structure.

  11. Ground based infrared astronomy

    NASA Technical Reports Server (NTRS)

    Jennings, D. E.

    1988-01-01

    Infrared spectroscopic instrumentation has been developed for ground-based measurements of astrophysical objects in the intermediate infrared. A conventional Michelson interferometer is limited for astronomical applications in the intermediate infrared by quantum noise fluctuations in the radiation form the source and/or background incident on the detector, and the multiplex advantage is no longer available. One feasible approach to recovering the multiplex advantage is post-dispersion. The infrared signal after passing through telescope and interferometer, is dispersed by a low resolution grating spectrometer onto an array of detectors. The feasibility of the post-dispersion system has been demonstrated with observations of astrophysical objects in the 5 and 10 micrometer atmospheric windows from ground-based telescopes. During FY87/88 the post-disperser was used at the Kitt Peak 4-meter telescope and McMath telescope with facility Fourier transform spectrometers. Jupiter, Saturn, Mars, and Venus were observed. On Jupiter, the resolution at 12 micrometer was 0.01/cm, considerably higher than had been acheived previously. The spectrum contains Jovian ethane and acetylene emission. Construction was begun on the large cryogenic grating spectrometer.

  12. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  13. Procedure of evaluating parameters of inland earthquakes caused by long strike-slip faults for ground motion prediction

    NASA Astrophysics Data System (ADS)

    Ju, Dianshu; Dan, Kazuo; Fujiwara, Hiroyuki; Morikawa, Nobuyuki

    2016-04-01

    We proposed a procedure of evaluating fault parameters of asperity models for predicting strong ground motions from inland earthquakes caused by long strike-slip faults. In order to obtain averaged dynamic stress drops, we adopted the formula obtained by dynamic fault rupturing simulations for surface faults of the length from 15 to 100 km, because the formula of the averaged static stress drops for circular cracks, commonly adopted in existing procedures, cannot be applied to surface faults or long faults. The averaged dynamic stress drops were estimated to be 3.4 MPa over the entire fault and 12.2 MPa on the asperities, from the data of 10 earthquakes in Japan and 13 earthquakes in other countries. The procedure has a significant feature that the average slip on the seismic faults longer than about 80 km is constant, about 300 cm. In order to validate our proposed procedure, we made a model for a 141 km long strike-slip fault by our proposed procedure for strike-slip faults, predicted ground motions, and showed that the resultant motions agreed well with the records of the 1999 Kocaeli, Turkey, earthquake (Mw 7.6) and with the peak ground accelerations and peak ground velocities by the GMPE of Si and Midorikawa (1999).

  14. Simulation of Strong Ground Motion for the 7.6Mw Kashmir Earthquake Occurred on 8 Oct 2005

    NASA Astrophysics Data System (ADS)

    Naveed, A.; Muhammad sohail, K.

    2015-12-01

    The Mw 7.6 Kashmir earthquake which struck the northern area of Pakistan , the Kashmir region on 8 October 2005.The epicenter was located 18km north-northeast of Muzaffarabad, with a focal depth of 26km and it occurred in the Hazara-kashmir syntaxial bend near Main Mantle Thrust (MMT). This is one of the most devastating earthquakes occurred along Himalayan Arc and brought more than 80,000 deaths and more than 5.2 billion USD economical loss. The earthquake had duration of 25s and 75km rupture length along the surface. In order to investigate the strong motion caused by this earthquake, we simulate the Kashmir earthquake by the Curved grid finite difference method (CG-FDM). The finite-fault rupture, real topography variations and modified crustal model are considered. Simulated results are compared with available records, showing good mutual agreement between the synthetic and observed ground motions. According to the Pakistan Meteorological Department (PMD), the intensity of four observed points had reached scale IX, whereas our simulated results show those points are located in the regions with our predicted intensity scale IX or VIII. Peak Ground Acceleration (PGA) and Peak ground velocity (PGV) are most important parameters for hazard analysis, and our results are sufficiently coincide with their observed values. Finally, we also discuss the significant effect of surface topography on ground motion resulting by the Earthquake.

  15. Empirical model of ionospheric storm effects on the F2 layer peak height associated with changes of peak electron density

    NASA Astrophysics Data System (ADS)

    Gulyaeva, T. L.

    2012-02-01

    An empirical model of storm-time behavior of the ionospheric peak height hmF2 associated with changes of peak electron density NmF2 is inferred from the topside true-height profiles provided by ISIS 1, ISIS 2, IK-19, and Cosmos-1809 satellites for the period of 1969-1987. The topside-derived quiet-time models of the ionospheric peak height hqF2 and peak electron density NqF2 are used as a frame of reference. To harmonize the model with storm and substorm effects induced by large-scale traveling ionospheric disturbances (LSTIDs), constraints are applied to the topside data, excluding their changes deviating above LSTID extreme limits. The degree of disturbance is estimated by the ionospheric weather W index; then, the least squares fitting is applied to the median of log(hm/hq) versus log(Nm/Nq). Anticorrelation between instant changes of hmF2 and NmF2 has a particular seasonal-magnetic latitude structure varying with solar activity that is used for the buildup of the analytical model. The model allows the deduction of the instantaneous hmF2 associated with the assessment or forecast of the respective NmF2. The model is validated with the data of five ground-based ionosondes during severe space weather storms at times of high solar activity (2000) and low solar activity (2006), and results agree reasonably well with the peak parameters derived from an ionogram. The model is incorporated into the coupled International Reference Ionosphere-Plasmasphere (IRI-Plas) code, used in the assimilative mode as the three-dimensional (3-D) interpolator of the GPS-derived total electron content, TECgps.

  16. Evaluating the compatibility of physics-based deterministic synthetic ground motion with empirical GMPE

    NASA Astrophysics Data System (ADS)

    Baumann, C.; Dalguer, L. A.

    2012-12-01

    Recent development of deterministic physics-based numerical simulations of earthquakes has contributed to substantial advances in our understanding of different aspects related to the earthquake mechanism and near source ground motion. These models have greater potential for identifying and predicting the variability of near-source ground motions dominated by the source and/or geological effects. These advances have led to increased interest in using suite of physics-based models for reliable prediction of ground motion of future earthquakes for seismic hazard assessment and risk mitigation, particularly in areas where there are few recorded ground motions. But before using synthetic ground motion, it is important to evaluate the reliability of deterministic synthetic ground motions, particularly the upper frequency limit. Current engineering practice usually use ground motion quantities estimated from empirical Ground Motion Predicting Equations (GMPE) such as peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), and spectral ordinates as input to assess building response for seismic safety of future and existing structures. Therefore it is intuitive and evident to verify the compatibility of synthetic ground motions with current empirical GMPE. In this study we attempt to do it so, to a suite of deterministic ground motion simulation generated by earthquake dynamic rupture models. We focus mainly on determining the upper frequency limit in which the synthetic ground motions are compatible to GMPE. For that purpose we have generated suite of earthquake rupture dynamic models in a layered 1D velocity structure. The simulations include 360 rupture dynamic models with moment magnitudes in the range of 5.5-7, for three styles of faulting (reverse, normal and strike slip), for both buried faults and surface rupturing faults. Normal stress and frictional strength are depth and non-depth dependent. Initial stress distribution follows

  17. Block ground interaction of rockfalls

    NASA Astrophysics Data System (ADS)

    Volkwein, Axel; Gerber, Werner; Kummer, Peter

    2016-04-01

    During a rockfall the interaction of the falling block with the ground is one of the most important factors that define the evolution of a rockfall trajectory. It steers the rebound, the rotational movement, possibly brake effects, friction losses and damping effects. Therefore, if most reliable rockfall /trajectory simulation software is sought a good understanding of the block ground interaction is necessary. Today's rockfall codes enable the simulation of a fully 3D modelled block within a full 3D surface . However, the details during the contact, i.e. the contact duration, the penetration depth or the dimension of the marks in the ground are usually not part of the simulation. Recent field tests with rocks between 20 and 80 kg have been conducted on a grassy slope in 2014 [1]. A special rockfall sensor [2] within the blocks measured the rotational velocity and the acting accelerations during the tests. External video records and a so-called LocalPositioningSystem deliver information on the travel velocity. With these data not only the flight phases of the trajectories but also the contacts with the ground can be analysed. During the single jumps of a block the flight time, jump length, the velocity, and the rotation are known. During the single impacts their duration and the acting accelerations are visible. Further, the changes of rotational and translational velocity influence the next jump of the block. The change of the rotational velocity over the whole trajectory nicely visualizes the different phases of a rockfall regarding general acceleration and deceleration in respect to the inclination and the topography of the field. References: [1] Volkwein A, Krummenacher B, Gerber W, Lardon J, Gees F, Brügger L, Ott T (2015) Repeated controlled rockfall trajectory testing. [Abstract] Geophys. Res. Abstr. 17: EGU2015-9779. [2] Volkwein A, Klette J (2014) Semi-Automatic Determination of Rockfall Trajectories. Sensors 14: 18187-18210.

  18. The 2001 Mw7.7 Bhuj, India Earthquake and Eastern North American Ground-Motion Attenuation Relations: Seismic Hazard Implications

    NASA Astrophysics Data System (ADS)

    Cramer, C. H.; Bhattacharya, S. N.; Kumar, A.

    2002-12-01

    It has been suggested that the Mw7.7 2001 Bhuj, India earthquake occurred in a stable continental region with ground-motion attenuation properties similar to eastern North America (ENA). No strong motion recordings for M7 or greater earthquakes have been recorded in ENA, so, if the two regions share similar properties, then observations from the Bhuj earthquake provide important information for hazard assessments in ENA as well as India. This thesis can be tested using seismic data for the Bhuj mainshock. The Indian Meteorological Department recorded accelerograph and broadband seismograph data at distances of 500 to 1800 km. Accelerograph and engineering seismoscope data were recorded at distances of 40 to 1100 km by the Department of Earthquake Engineering at the Indian Institute of Technology, Roorkee. We have processed the accelerograph and broadband data for response spectral accelerations and corrected them to a common NEHRP site class using Joyner and Boore (2000) site factors. The geologic conditions at each recording site were determined using the geologic map of India and categorized as Quaternary sediments, Tertiary sediments, or hard rock. Comparisons were then made to available ENA ground-motion attenuation relations. For peak ground acceleration (PGA) and 1.0 s spectral acceleration (Sa), the geologically-corrected Bhuj data generally fall among the ENA ground-motion attenuation relations. The Bhuj mainshock ground-motion data agree with the collective predictions of the ENA relations given the random uncertainty in ground-motion measurements of a factor of two or more plus the ground-motion attenuation relation modeling uncertainty. From an engineering perspective, this comparison supports the thesis that seismic-wave attenuation in stable continental India is similar to eastern North America.

  19. Update of the Graizer-Kalkan ground-motion prediction equations for shallow crustal continental earthquakes

    USGS Publications Warehouse

    Graizer, Vladimir; Kalkan, Erol

    2015-01-01

    A ground-motion prediction equation (GMPE) for computing medians and standard deviations of peak ground acceleration and 5-percent damped pseudo spectral acceleration response ordinates of maximum horizontal component of randomly oriented ground motions was developed by Graizer and Kalkan (2007, 2009) to be used for seismic hazard analyses and engineering applications. This GMPE was derived from the greatly expanded Next Generation of Attenuation (NGA)-West1 database. In this study, Graizer and Kalkan’s GMPE is revised to include (1) an anelastic attenuation term as a function of quality factor (Q0) in order to capture regional differences in large-distance attenuation and (2) a new frequency-dependent sedimentary-basin scaling term as a function of depth to the 1.5-km/s shear-wave velocity isosurface to improve ground-motion predictions for sites on deep sedimentary basins. The new model (GK15), developed to be simple, is applicable to the western United States and other regions with shallow continental crust in active tectonic environments and may be used for earthquakes with moment magnitudes 5.0–8.0, distances 0–250 km, average shear-wave velocities 200–1,300 m/s, and spectral periods 0.01–5 s. Directivity effects are not explicitly modeled but are included through the variability of the data. Our aleatory variability model captures inter-event variability, which decreases with magnitude and increases with distance. The mixed-effects residuals analysis shows that the GK15 reveals no trend with respect to the independent parameters. The GK15 is a significant improvement over Graizer and Kalkan (2007, 2009), and provides a demonstrable, reliable description of ground-motion amplitudes recorded from shallow crustal earthquakes in active tectonic regions over a wide range of magnitudes, distances, and site conditions.

  20. In Brief: Timing of peak oil uncertain

    NASA Astrophysics Data System (ADS)

    Zielinski, Sarah

    2007-04-01

    According to the Hubbert peak theory, oil production in any geographic area will follow a bellshaped curve. The timing of the `peak' in global oil production is important because after that point, there will be less and less oil available for consumption. A new report from the U.S. Government Accountability Office found that most studies estimate that peak oil production will occur sometime between now and 2040. The uncertainty in these estimates could be reduced with better information about worldwide supply and demand, and alternative fuels and transportation technologies could mitigate the effects of a global decline in oil production. However, the report found no coordinated U.S. federal strategy to address these issues. The report, ``Uncertainty about Future Oil Supply Makes It Important to Develop a Strategy for Addressing a Peak and Decline in Oil Production,'' is available at http://www.gao.gov/cgi-bin/getrpt?GAO-07-283

  1. Reducing Peak Demand by Time Zone Divisions

    NASA Astrophysics Data System (ADS)

    Chakrabarti, A.

    2014-09-01

    For a large country like India, the electrical power demand is also large and the infrastructure cost for power is the largest among all the core sectors of economy. India has an emerging economy which requires high rate of growth of infrastructure in the power generation, transmission and distribution. The current peak demand in the country is approximately 1,50,000 MW which shall have a planned growth of at least 50 % over the next five years (Seventeenth Electric Power Survey of India, Central Electricity Authority, Government of India, March 2007). By implementing the time zone divisions each comprising of an integral number of contiguous states based on their total peak demand and geographical location, the total peak demand of the nation can be significantly cut down by spreading the peak demand of various states over time. The projected reduction in capital expenditure over a plan period of 5 years is substantial. Also, the estimated reduction in operations expenditure cannot be ignored.

  2. Tectonics, Climate and Earth's highest peaks

    NASA Astrophysics Data System (ADS)

    Robl, Jörg; Prasicek, Günther; Hergarten, Stefan

    2016-04-01

    Prominent peaks characterized by high relief and steep slopes are among the most spectacular morphological features on Earth. In collisional orogens they result from the interplay of tectonically driven crustal thickening and climatically induced destruction of overthickened crust by erosional surface processes. The glacial buzz-saw hypothesis proposes a superior status of climate in limiting mountain relief and peak altitude due to glacial erosion. It implies that peak altitude declines with duration of glacial occupation, i.e., towards high latitudes. This is in strong contrast with high peaks existing in high latitude mountain ranges (e.g. Mt. St. Elias range) and the idea of peak uplift due to isostatic compensation of spatially variable erosional unloading an over-thickened orogenic crust. In this study we investigate landscape dissection, crustal thickness and vertical strain rates in tectonically active mountain ranges to evaluate the influence of erosion on (latitudinal) variations in peak altitude. We analyze the spatial distribution of serval thousand prominent peaks on Earth extracted from the global ETOPO1 digital elevation model with a novel numerical tool. We compare this dataset to crustal thickness, thickening rate (vertical strain rate) and mean elevation. We use the ratios of mean elevation to peak elevation (landscape dissection) and peak elevation to crustal thickness (long-term impact of erosion on crustal thickness) as indicators for the influence of erosional surface processes on peak uplift and the vertical strain rate as a proxy for the mechanical state of the orogen. Our analysis reveals that crustal thickness and peak elevation correlate well in orogens that have reached a mechanically limited state (vertical strain rate near zero) where plate convergence is already balanced by lateral extrusion and gravitational collapse and plateaus are formed. On the Tibetan Plateau crustal thickness serves to predict peak elevation up to an altitude

  3. Flu Season Hasn't Peaked Yet

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_157852.html Flu Season Hasn't Peaked Yet This year's vaccine ... 2016 FRIDAY, March 18, 2016 (HealthDay News) -- This flu season continues to be the mildest in the ...

  4. Observing at Kitt Peak National Observatory.

    ERIC Educational Resources Information Center

    Cohen, Martin

    1981-01-01

    Presents an abridged version of a chapter from the author's book "In Quest of Telescopes." Includes personal experiences at Kitt Peak National Observatory, and comments on telescopes, photographs, and making observations. (SK)

  5. Helping System Engineers Bridge the Peaks

    NASA Technical Reports Server (NTRS)

    Rungta, Neha; Tkachuk, Oksana; Person, Suzette; Biatek, Jason; Whalen, Michael W.; Castle, Joseph; Castle, JosephGundy-Burlet, Karen

    2014-01-01

    In our experience at NASA, system engineers generally follow the Twin Peaks approach when developing safety-critical systems. However, iterations between the peaks require considerable manual, and in some cases duplicate, effort. A significant part of the manual effort stems from the fact that requirements are written in English natural language rather than a formal notation. In this work, we propose an approach that enables system engineers to leverage formal requirements and automated test generation to streamline iterations, effectively "bridging the peaks". The key to the approach is a formal language notation that a) system engineers are comfortable with, b) is supported by a family of automated V&V tools, and c) is semantically rich enough to describe the requirements of interest. We believe the combination of formalizing requirements and providing tool support to automate the iterations will lead to a more efficient Twin Peaks implementation at NASA.

  6. Correlation of ground motion and intensity for the 17 January 1994 Northridge, California, earthquake

    USGS Publications Warehouse

    Boatwright, J.; Thywissen, K.; Seekins, L.C.

    2001-01-01

    We analyze the correlations between intensity and a set of groundmotion parameters obtained from 66 free-field stations in Los Angeles County that recorded the 1994 Northridge earthquake. We use the tagging intensities from Thywissen and Boatwright (1998) because these intensities are determined independently on census tracts, rather than interpolated from zip codes, as are the modified Mercalli isoseismals from Dewey et al. (1995). The ground-motion parameters we consider are the peak ground acceleration (PGA), the peak ground velocity (PGV), the 5% damped pseudovelocity response spectral (PSV) ordinates at 14 periods from 0.1 to 7.5 sec, and the rms average of these spectral ordinates from 0.3 to 3 sec. Visual comparisons of the distribution of tagging intensity with contours of PGA, PGV, and the average PSV suggest that PGV and the average PSV are better correlated with the intensity than PGA. The correlation coefficients between the intensity and the ground-motion parameters bear this out: r = 0.75 for PGA, 0.85 for PGV, and 0.85 for the average PSV. Correlations between the intensity and the PSV ordinates, as a function of period, are strongest at 1.5 sec (r = 0.83) and weakest at 0.2 sec (r = 0.66). Regressing the intensity on the logarithms of these ground-motion parameters yields relations I ?? mlog?? with 3.0 ??? m ??? 5.2 for the parameters analyzed, where m = 4.4 ?? 0.7 for PGA, 3.4 ?? 0.4 for PGV, and 3.6 ?? 0.5 for the average PSV.

  7. Seismic Wave Amplification in Las Vegas: Site Response and Empirical Estimates of Ground Motion

    NASA Astrophysics Data System (ADS)

    Rodgers, A.; McCallen, D.; Tkalcic, H.; Wagoner, J.; Louie, J.; Anderson, J.; Luke, B.; Snelson, C.; Taylor, W.

    2004-12-01

    This presentation will summarize a multidisciplinary effort to understand seismic wave amplification in Las Vegas Valley. The project involves weak motion recording and analysis, geotechnical and seismic refraction field studies, geologic and lithologic interpretation and model building. We will provide a brief overview of the project, then focus on specifics of seismic wave amplification including observations and interpretations. We analyzed recordings of nuclear explosions from the Nevada Test Site (NTS) and regional earthquakes to estimate site response in Las Vegas. An empirical transfer function method was used to transform ground motion time-series at one (reference) station to other stations, using frequency dependent site response curves in the band 0.2-5.0 Hz. The method transforms the time-series to the frequency domain by Fast Fourier transform, multiplies the amplitude spectrum by the site response curve and inverse FFT's back to the time domain. The approach is validated by the ability to predict horizontal component S-wave ground motion measures, such as peak and rms ground velocities and accelerations. We then can provide empirical estimates of ground motion for a wider distribution of sites in Las Vegas. Frequency dependent amplifications (site response) and peak ground motions are strongly correlated with measures of shallow shear-wave (geotechnical) velocities. Details of the geotechnical measurements and models will be presented in a companion presentation. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  8. Measuring both Rotational and Translational Ground-Motions from Explosions and Local Earthquakes in Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, B.; Lee, W.; Lin, C.; Liu, C.; Shin, T.; Teng, T.; Wu, C.

    2008-12-01

    Since rotational motions can "contaminate" translational ground-motion measurements due to the induced perturbation of the Earth's gravitational field, we started a program to measure rotational ground motions near Hualien (Taiwan) in December, 2000. However, no useful data were obtained after 3 years, until a rotational sensor of much higher sensitivity was deployed at the HGSD station in eastern Taiwan in December, 2004. Rotational and translational seismograms were obtained from several hundred local earthquakes. As noted by several authors before, we found a linear relationship between peak rotational rate (PRR in mrad/s) and peak ground acceleration (PGA in m/s2) from local earthquakes in Taiwan: PRR = 0.002 + 1.301 PGA, with a correlation coefficient of 0.988. Taking advantage of two large explosions of the TAIGER Active Seismic Experiment, we deployed 13 accelerometers and 8 rotational sensors within 600 m from the N3 shot points and obtained some interesting results, which will be presented by Langston et al. in this Session. In December, 2007, we began an instrument array deployment along the Meishan fault in southwestern Taiwan, where a major earthquake occurred in 1906 with surface rupture of more than 12 km long. The deployed instruments are: (1) a 32-element seismic array in free-field, (2) a 32-element accelerometer array in a building, (3) a six-channel unit with a low-gain broadband seismometer and an accelerometer, and (4) two six-channel units with an accelerometer and an external rotational senor. We have 8 rotational sensors now deployed in Taiwan and seven new rotational sensors are scheduled for deployment soon in a program to assess the effect of ground rotation on traditional measurements of translational strong ground motions.

  9. Extensive air showers, lightning, and thunderstorm ground enhancements

    NASA Astrophysics Data System (ADS)

    Chilingarian, A.; Hovsepyan, G.; Kozliner, L.

    2016-09-01

    For lightning research, we monitor particle fluxes from thunderclouds, the so-called thunderstorm ground enhancements (TGEs) initiated by runaway electrons, and extensive air showers (EASs) originating from high-energy protons or fully stripped nuclei that enter the Earth's atmosphere. We also monitor the near-surface electric field and atmospheric discharges using a network of electric field mills. The Aragats "electron accelerator" produced several TGEs and lightning events in the spring of 2015. Using 1-s time series, we investigated the relationship between lightning and particle fluxes. Lightning flashes often terminated the particle flux; in particular, during some TGEs, lightning events would terminate the particle flux thrice after successive recovery. It was postulated that a lightning terminates a particle flux mostly in the beginning of a TGE or in its decay phase; however, we observed two events (19 October 2013 and 20 April 2015) when the huge particle flux was terminated just at the peak of its development. We discuss the possibility of a huge EAS facilitating lightning leader to find its path to the ground.

  10. Relativistic klystron research for high gradient accelerators

    SciTech Connect

    Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fowkes, W.R.; Herrmannsfeldt, W.B.; Higo, T.; Hoag, H.A.; Lavine, T.L.; Lee, T.G.

    1988-06-01

    Relativistic klystrons are being developed as a power source for high gradient accelerator applications which include large linear electron--positron colliders, compact accelerators, and FEL sources. We have attained 200MW peak power at 11.4 GHz from a relativistic klystron, and 140 MV/m longitudinal gradient in a short 11.4 GHz accelerator section. We report here on the design of our first klystrons, the results of our experiments so far, and some of our plans for the near future. 5 refs., 7 figs.

  11. Forward-peaked scattering of polarized light.

    PubMed

    Clark, Julia P; Kim, Arnold D

    2014-11-15

    Polarized light propagation in a multiple scattering medium is governed by the vector radiative transfer equation. We analyze the vector radiative transfer equation in asymptotic limit of forward-peaked scattering and derive an approximate system of equations for the Stokes parameters, which we call the vector Fokker-Planck approximation. The vector Fokker-Planck approximation provides valuable insight into several outstanding issues regarding the forward-peaked scattering of polarized light such as the polarization memory phenomenon. PMID:25490484

  12. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  13. Cosmic microwave background acoustic peak locations

    NASA Astrophysics Data System (ADS)

    Pan, Z.; Knox, L.; Mulroe, B.; Narimani, A.

    2016-07-01

    The Planck collaboration has measured the temperature and polarization of the cosmic microwave background well enough to determine the locations of eight peaks in the temperature (TT) power spectrum, five peaks in the polarization (EE) power spectrum and 12 extrema in the cross (TE) power spectrum. The relative locations of these extrema give a striking, and beautiful, demonstration of what we expect from acoustic oscillations in the plasma; e.g. that EE peaks fall half way between TT peaks. We expect this because the temperature map is predominantly sourced by temperature variations in the last scattering surface, while the polarization map is predominantly sourced by gradients in the velocity field, and the harmonic oscillations have temperature and velocity 90 deg out of phase. However, there are large differences in expectations for extrema locations from simple analytic models versus numerical calculations. Here, we quantitatively explore the origin of these differences in gravitational potential transients, neutrino free-streaming, the breakdown of tight coupling, the shape of the primordial power spectrum, details of the geometric projection from three to two dimensions, and the thickness of the last scattering surface. We also compare the peak locations determined from Planck measurements to expectations under the Λ cold dark matter model. Taking into account how the peak locations were determined, we find them to be in agreement.

  14. Peak Effect in High-Tc Superconductors

    NASA Astrophysics Data System (ADS)

    Ling, Xinsheng

    1996-03-01

    Like many low-Tc superconductors, high-quality YBCO single crystals are found(X.S. Ling and J.I. Budnick, in Magnetic Susceptibility of Superconductors and Other Spin Systems), edited by R.A. Hein, T.L. Francavilla, and D.H. Liebenberg (Plenum Press, New York, 1991), p.377. to exhibit a striking peak effect. In a magnetic field, the temperature dependence of the critical current has a pronounced peak below T_c(H). Pippard(A.B. Pippard, Phil. Mag. 19), 217 (1969)., and subsequently Larkin and Ovchinnikov(A.I. Larkin and Yu.N. Ovchinnikov, J. Low Temp. Phys. 34), 409 (1979)., attributed the onset of the peak effect to a softening of the vortex lattice. In this talk, the experimental discovery^1 of the peak effect in high-Tc superconductors will be described, followed by a brief historical perspective of the understanding of this phenomenon and a discussion of a new model(X.S. Ling, C. Tang, S. Bhattacharya, and P.M. Chaikin, cond-mat/9504109, (NEC Preprint 1995).) for the peak effect. In this model, the peak effect is an interesting manifestation of the vortex-lattice melting in the presence of weak random pinning potentials. The rise of critical current with increasing temperature is a signature of the ``melting'' of the Larkin domains. This work is done in collaboration with Joe Budnick, Chao Tang, Shobo Bhattacharya, Paul Chaikin, and Boyd Veal.

  15. Stochastic Ground Motion Simulation with Site Correction in Ilan Area, Northeastern Taiwan

    NASA Astrophysics Data System (ADS)

    NFN, Megawati; Kuo-Liang, Wen

    2015-04-01

    Earthquake waveform is controlled by three factors - source properties, path characteristics, and local site effects. The local site effect is the important factor participate strong ground motion prediction. In this study, we used stochastic point-source method for simulating ground motion (Boore, 2005). This method has been widely used in the development of ground-motion prediction equation and in modeling the parameters that controls observed ground motion (Atkinson et al., 2009). The shallow earthquake events which recorded by Taiwan Strong Motion Instrumentation Program (TSMIP) from 1992 to 2012 are simulated with the stochastic point-source method (Boore, 1983; Boore, 2003). The earthquake records are selected with the depth from 0 to 30 km and the magnitude (Mw) from 4 to 6.5. The study area is situated in Ilan area which is located in the northeastern Taiwan. There are 70 TSMIP stations which based on the Vs30 consist of site class B, C, D, and E. Seismic parameters for stochastic method were selected based on previous studies (Sokolov et al., 2006; 2009). The crustal amplification parameter is set to the halfspace. The empirical transfer functions from 0.2 Hz to 10 Hz for each station in Ilan area will be calculated by H/H method between observed and simulated spectra (Borcheret, 1970). Ground motion prediction is calculated by selecting several target events for stochastic point-source simulating to the halfspace. The prediction of peak ground acceleration (PGA) is estimated after doing the site correction with the empirical transfer function. Finally, the simulated ground motion was compared in time domain (PGA) and frequency domain (Degree of spectrum difference, DSPD) to show the goodness of the simulation. Keywords : Stochastic point-source method, Site effect, Empirical transfer function

  16. Ground water contamination

    SciTech Connect

    Not Available

    1991-01-01

    This book covers: Ground water contamination and basic concepts of water law; Federal law governing water contamination and remediation; Ground water flow and contaminant migration; Ground water cleanup under CERCLA; Technical methods of remediation and prevention of contamination; Liability for ground water contamination; State constraints on contamination of ground water; Water quantity versus water quality; Prevention of use of contaminated ground water as an alternative to remediation; Economic considerations in liability for ground water contamination; and Contamination, extraction, and injection issues.

  17. Prediction of ground motion parameters for the volcanic area of Mount Etna

    NASA Astrophysics Data System (ADS)

    Tusa, Giuseppina; Langer, Horst

    2016-01-01

    Ground motion prediction equations (GMPEs) have been derived for peak ground acceleration (PGA), velocity (PGV), and 5 % damped spectral acceleration (PSA) at frequencies between 0.1 and 10 Hz for the volcanic area of Mt. Etna. The dataset consists of 91 earthquakes with epicentral distances between 0.5 and 100 km. Given the specific characteristics of the area, we divided our data set into two groups: shallow events (SE, focal depth <5 km), and deep events (DE, focal depth >5 km). The range of magnitude covered by the SE and the DE is 3.0 ≤ M L ≤ 4.3 and 3.0 ≤ M L ≤ 4.8, respectively. Signals of DE typically have more high frequencies than those of SE. These differences are clearly reflected in the empirical GMPEs of the two event groups. Empirical GMPEs were estimated considering several functional forms: Sabetta and Pugliese (Bull Seism Soc Am 77:1491-1513, 1987) (SP87), Ambraseys et al. (Earth Eng Struct Dyn 25:371-400, 1996) (AMB96), and Boore and Atkinson (Earth Spectra 24:99-138, 2008) (BA2008). From ANOVA, we learn that most of the errors in our GMPEs can be attributed to unmodeled site effects, whereas errors related to event parameters are limited. For DE, BA2008 outperforms the simpler models SP87 or AMB96. For SE, the simple SP87 is preferable considering the Bayesian Information Criterion since it proves more stable with respect to confidence and gives very similar or even lower prediction errors during cross-validation than the BA2008 model. We compared our results to relationships derived for Italy (ITA10, Bindi et al. Bull Earth Eng 99:2471-2488, 2011). For SE, the main differences are observed for distances greater than about 5 km for both horizontal and vertical PGAs. Conversely, for DE the ITA10 heavily overestimates the peak ground parameters for short distances.

  18. Strong Ground Motion Database System for the Mexican Seismic Network

    NASA Astrophysics Data System (ADS)

    Perez-Yanez, C.; Ramirez-Guzman, L.; Ruiz, A. L.; Delgado, R.; Macías, M. A.; Sandoval, H.; Alcántara, L.; Quiroz, A.

    2014-12-01

    A web-based system for strong Mexican ground motion records dissemination and archival is presented. More than 50 years of continuous strong ground motion instrumentation and monitoring in Mexico have provided a fundamental resource -several thousands of accelerograms- for better understanding earthquakes and their effects in the region. Lead by the Institute of Engineering (IE) of the National Autonomous University of Mexico (UNAM), the engineering strong ground motion monitoring program at IE relies on a continuously growing network, that at present includes more than 100 free-field stations and provides coverage to the seismic zones in the country. Among the stations, approximately 25% send the observed acceleration to a processing center in Mexico City in real-time, and the rest require manual access, remote or in situ, for later processing and cataloguing. As part of a collaboration agreement between UNAM and the National Center for Disaster Prevention, regarding the construction and operation of a unified seismic network, a web system was developed to allow access to UNAM's engineering strong motion archive and host data from other institutions. The system allows data searches under a relational database schema, following a general structure relying on four databases containing the: 1) free-field stations, 2) epicentral location associated with the strong motion records available, 3) strong motion catalogue, and 4) acceleration files -the core of the system. In order to locate and easily access one or several records of the data bank, the web system presents a variety of parameters that can be involved in a query (seismic event, region boundary, station name or ID, radial distance to source or peak acceleration). This homogeneous platform has been designed to facilitate dissemination and processing of the information worldwide. Each file, in a standard format, contains information regarding the recording instrument, the station, the corresponding earthquake

  19. Predicting Peak Flows following Forest Fires

    NASA Astrophysics Data System (ADS)

    Elliot, William J.; Miller, Mary Ellen; Dobre, Mariana

    2016-04-01

    Following forest fires, peak flows in perennial and ephemeral streams often increase by a factor of 10 or more. This increase in peak flow rate may overwhelm existing downstream structures, such as road culverts, causing serious damage to road fills at stream crossings. In order to predict peak flow rates following wildfires, we have applied two different tools. One is based on the U.S.D.A Natural Resource Conservation Service Curve Number Method (CN), and the other is by applying the Water Erosion Prediction Project (WEPP) to the watershed. In our presentation, we will describe the science behind the two methods, and present the main variables for each model. We will then provide an example of a comparison of the two methods to a fire-prone watershed upstream of the City of Flagstaff, Arizona, USA, where a fire spread model was applied for current fuel loads, and for likely fuel loads following a fuel reduction treatment. When applying the curve number method, determining the time to peak flow can be problematic for low severity fires because the runoff flow paths are both surface and through shallow lateral flow. The WEPP watershed version incorporates shallow lateral flow into stream channels. However, the version of the WEPP model that was used for this study did not have channel routing capabilities, but rather relied on regression relationships to estimate peak flows from individual hillslope polygon peak runoff rates. We found that the two methods gave similar results if applied correctly, with the WEPP predictions somewhat greater than the CN predictions. Later releases of the WEPP model have incorporated alternative methods for routing peak flows that need to be evaluated.

  20. Empirical predictive model for the vmax/ amax ratio of strong ground motions using genetic programming

    NASA Astrophysics Data System (ADS)

    Jafarian, Yaser; Kermani, Elnaz; Baziar, Mohammad H.

    2010-12-01

    Earthquake-induced deformation of structures is strongly influenced by the frequency content of input motion. Nevertheless, state-of-the-practice studies commonly use the intensity measures such as peak ground acceleration ( PGA), which are not frequency dependent. The vmax/ amax ratio of strong ground motions can be used in seismic hazard studies as a parameter that captures the influence of frequency content. In the present study, genetic programming (GP) is employed to develop a new empirical predictive equation for the vmax/ amax ratio of the shallow crustal strong ground motions recorded at free field sites. The proposed model is a function of earthquake magnitude, closest distance from source to site ( Rclstd), faulting mechanism, and average shear wave velocity over the top 30 m of site ( Vs30 ). A wide-ranging database of strong ground motion released by Pacific Earthquake Engineering Research Center (PEER) was utilized. It is demonstrated that residuals of the final equation show insignificant bias against the variations of the predictive parameters. The results indicate that vmax/ amax increases through increasing earthquake magnitude and source-to-site distance while magnitude dependency is considerably more than distance dependency. In addition, the proposed model predicts higher vmax/ amax ratio at softer sites that possess higher fundamental periods. Consequently, as an instance for the application of the proposed model, its reasonable performance in liquefaction potential assessment of sands and silty sands is presented.

  1. Ground motion values for use in the seismic design of the Trans-Alaska Pipeline system

    USGS Publications Warehouse

    Page, Robert A.; Boore, D.M.; Joyner, W.B.; Coulter, H.W.

    1972-01-01

    The proposed trans-Alaska oil pipeline, which would traverse the state north to south from Prudhoe Bay on the Arctic coast to Valdez on Prince William Sound, will be subject to serious earthquake hazards over much of its length. To be acceptable from an environmental standpoint, the pipeline system is to be designed to minimize the potential of oil leakage resulting from seismic shaking, faulting, and seismically induced ground deformation. The design of the pipeline system must accommodate the effects of earthquakes with magnitudes ranging from 5.5 to 8.5 as specified in the 'Stipulations for Proposed Trans-Alaskan Pipeline System.' This report characterizes ground motions for the specified earthquakes in terms of peak levels of ground acceleration, velocity, and displacement and of duration of shaking. Published strong motion data from the Western United States are critically reviewed to determine the intensity and duration of shaking within several kilometers of the slipped fault. For magnitudes 5 and 6, for which sufficient near-fault records are available, the adopted ground motion values are based on data. For larger earthquakes the values are based on extrapolations from the data for smaller shocks, guided by simplified theoretical models of the faulting process.

  2. Liquefaction, ground oscillation, and soil deformation at the Wildlife Array, California

    USGS Publications Warehouse

    Holzer, T.L.; Youd, T.L.

    2007-01-01

    Excess pore-water pressure and liquefaction at the Wildlife Liquefaction Array in 1987 were caused by deformation associated with both high-frequency strong ground motion and 5.5-second-period Love waves. The Love waves produced large (???1.5%) cyclic shear strains well after the stronger high-frequency ground motion abated. These cyclic strains generated approximately from 13 to 35% of the excess pore-water pressure in the liquefied layer and caused excess pore-water pressures ultimately to reach effective overburden stress. The deformation associated with the Love waves explains the "postearthquake" increase of pore-water pressure that was recorded at the array. This explanation suggests that conventional methods for predicting liquefaction based on peak ground acceleration are incomplete and may need to consider cyclic strains associated with long-period surface waves. A post-earthquake survey of an inclinometer casing indicated permanent shear strain associated with lateral spreading primarily occurred in the upper part of the liquefied layer. Comparison of cone penetration test soundings conducted after the earthquake with pre-earthquake soundings suggests sleeve friction increased. Natural lateral variability of the liquefied layer obscured changes in tip resistance despite a ???1% reduction in volume. The large oscillatory motion associated with surface waves explains ground oscillation that has been reported at some liquefaction sites during earthquakes.

  3. Effect of Footwear Modifications on Oscillations at the Achilles Tendon during Running on a Treadmill and Over Ground: A Cross-Sectional Study

    PubMed Central

    Meinert, Ilka; Brown, Niklas; Alt, Wilfried

    2016-01-01

    Background Achilles tendon injuries are known to commonly occur in runners. During running repeated impacts are transferred in axial direction along the lower leg, therefore possibly affecting the oscillation behavior of the Achilles tendon. The purpose of the present study was to explore the effects of different footwear modifications and different ground conditions (over ground versus treadmill) on oscillations at the Achilles tendon. Methods Oscillations were measured in 20 male runners using two tri-axial accelerometers. Participants ran in three different shoe types on a treadmill and over ground. Data analysis was limited to stance phase and performed in time and frequency space. Statistical comparison was conducted between oscillations in vertical and horizontal direction, between running shoes and between ground conditions (treadmill versus over ground running). Results Differences in the oscillation behavior could be detected between measurement directions with peak accelerations in the vertical being lower than those in the horizontal direction, p < 0.01. Peak accelerations occurred earlier at the distal accelerometer than at the proximal one, p < 0.01. Average normalized power differed between running shoes (p < 0.01) with harder damping material resulting in higher power values. Little to no power attenuation was found between the two accelerometers. Oscillation behavior of the Achilles tendon is not influenced by ground condition. Conclusion Differences in shoe configurations may lead to variations in running technique and impact forces and therefore result in alterations of the vibration behavior at the Achilles tendon. The absence of power attenuation may have been caused by either a short distance between the two accelerometers or high stiffness of the tendon. High stiffness of the tendon will lead to complete transmission of the signal along the Achilles tendon and therefore no attenuation occurs. PMID:27010929

  4. IMPULSIVE ACCELERATION OF CORONAL MASS EJECTIONS. II. RELATION TO SOFT X-RAY FLARES AND FILAMENT ERUPTIONS

    SciTech Connect

    Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M.; Vrsnak, B.

    2012-08-10

    Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher peak accelerations and lower acceleration phase durations, initiation heights, and heights, at which they reach their peak velocities and peak accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME peak acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME acceleration duration and negatively correlated with the CME peak acceleration. For the majority of the events the CME acceleration starts before the flare onset (for 75% of the events) and the CME acceleration ends after the soft X-ray (SXR) peak time (for 77% of the events). In {approx}60% of the events, the time difference between the peak time of the flare SXR flux derivative and the peak time of the CME acceleration is smaller than {+-}5 minutes, which hints at a feedback relationship between the CME acceleration and the energy release in the associated flare due to magnetic reconnection.

  5. Ground Motions at a Network of Strong Motion Accelerometers on the Hanford Site, Southeastern Washington, From the 28 February 2001 Nisqually Earthquake

    NASA Astrophysics Data System (ADS)

    Rohay, A.; Reidel, S.; Hartshorn, D.; Valenta, M.

    2001-12-01

    We have been operating five free-field strong motion accelerometers (SMA) at locations near the facilities on the Hanford Site since November 1998. The 28 February 2001 Nisqually earthquake was the first earthquake to be recorded by these instruments. The USGS and Caltech each operate one additional SMA/broadband seismometer site at Hanford (stations HAWA and LTH). Taken together, the elements of this network have an inter-station spacing of 8-12 km. The distance range of the instruments from the epicenter is 245-277 km. Peak ground accelerations ranged from 0.0016 to 0.0035 g (vertical), from 0.0017 to 0.0057 g (radial), and from 0.0022 to 0.0064 g (transverse). The lowest accelerations were observed at the bedrock site HAWA, but accelerations at another station on soil (H300A) were not significantly larger. The other stations on soil show significant amplification across the frequency spectrum and also within variable, narrow frequency ranges. For example, Fourier spectra from the station H100K, the furthest north of these stations, shows nearly a factor of 10 amplification of the transverse ground acceleration in the frequency range 0.5 to 1.0 Hz relative to the bedrock station. We are investigating the differences in soil geology beneath the network of SMA stations to understand these effects. The ground motions recorded from this earthquake are significantly lower than those predicted by intra-slab earthquake ground motion attenuation relationships that were used for Hanford's probabilistic seismic hazard assessment. Although these relationships include statistical variation in ground motion, they do not predict the range of amplification determined at the soil sites for this earthquake. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy under contract DE-AC06-76RL01830.

  6. Nasal peak inspiratory flow at altitude.

    PubMed

    Barry, P W; Mason, N P; Richalet, J P

    2002-01-01

    The present study investigated whether there are changes in nasal peak inspiratory flow (NPIF) during hypobaric hypoxia under controlled environmental conditions. During operation Everest III (COMEX '97), eight subjects ascended to a simulated altitude of 8,848 m in a hypobaric chamber. NPIF was recorded at simulated altitudes of 0 m, 5,000 m and 8,000 m. Oral peak inspiratory and expiratory flow (OPIF, OPEF) were also measured. Ambient air temperature and humidity were controlled. NPIF increased by a mean +/- SD of 16 +/- 12% from sea level to 8,000 m, whereas OPIF increased by 47 +/- 14%. NPIF rose by 0.085 +/- 0.03 L x s(-1) per kilometre of ascent (p<0.05), significantly less than the rise in OPIF and OPEF of 0.35 +/- 0.10 and 0.33 +/- 0.04 L x s(-1) per kilometre (p<0.0005). Nasal peak inspiratory flow rises with ascent to altitude. The rise in nasal peak inspiratory flow with altitude was far less than oral peak inspiratory flow and less than the predicted rise according to changes in air density. This suggests flow limitation at the nose, and occurs under controlled environmental conditions, refuting the hypothesis that nasal blockage at altitude is due to the inhalation of cold, dry air. Further work is needed to determine if nasal blockage limits activity at altitude. PMID:11843316

  7. Optical Phase Locking of Modelocked Lasers for Particle Accelerators

    SciTech Connect

    Plettner, T.; Sinha, S.; Wisdom, J.; Colby, E.R.; /SLAC

    2006-02-17

    Particle accelerators require precise phase control of the electric field through the entire accelerator structure. Thus a future laser driven particle accelerator will require optical synchronism between the high-peak power laser sources that power the accelerator. The precise laser architecture for a laser driven particle accelerator is not determined yet, however it is clear that the ability to phase-lock independent modelocked oscillators will be of crucial importance. We report the present status on our work to demonstrate long term phaselocking between two modelocked lasers to within one degree of optical phase and describe the optical synchronization techniques that we employ.

  8. SPANISH PEAKS WILDERNESS STUDY AREA, COLORADO.

    USGS Publications Warehouse

    Budding, Karin E.; Kluender, Steven E.

    1984-01-01

    A geologic and geochemical investigation and a survey of mines and prospects were conducted to evaluate the mineral-resource potential of the Spanish Peaks Wilderness Study Area, Huerfano and Las Animas Counties, in south-central Colorado. Anomalous gold, silver, copper, lead, and zinc concentrations in rocks and in stream sediments from drainage basins in the vicinity of the old mines and prospects on West Spanish Peak indicate a substantiated mineral-resource potential for base and precious metals in the area surrounding this peak; however, the mineralized veins are sparse, small in size, and generally low in grade. There is a possibility that coal may underlie the study area, but it would be at great depth and it is unlikely that it would have survived the intense igneous activity in the area. There is little likelihood for the occurrence of oil and gas because of the lack of structural traps and the igneous activity.

  9. The PEAK experience in South Carolina

    SciTech Connect

    1998-11-01

    The PEAK Institute was developed to provide a linkage for formal (schoolteachers) and nonformal educators (extension agents) with agricultural scientists of Clemson University`s South Carolina Agricultural Experiment Station System. The goal of the Institute was to enable teams of educators and researchers to develop and provide PEAK science and math learning experiences related to relevant agricultural and environmental issues of local communities for both classroom and 4-H Club experiences. The Peak Institute was conducted through a twenty day residential Institute held in June for middle school and high school teachers who were teamed with an Extension agent from their community. These educators participated in hands-on, minds-on sessions conducted by agricultural researchers and Clemson University Cooperative Extension specialists. Participants were given the opportunity to see frontier science being conducted by scientists from a variety of agricultural laboratories.

  10. Paleomagnetism of the Becker Peak stock

    NASA Astrophysics Data System (ADS)

    Miller, B. A.; Housen, B. A.

    2009-12-01

    Paleomagnetic studies of plutonic rocks, although subject to uncertainty due to lack of paleohorizontal control, can provide important constrains of patterns of regional deformation, and can play a role in evaluation of tectonic models and reconstructions. Many plutonic rocks of the Cascades have been well-studied via paleomagnetism, but there are many that lack robust data sets. One such pluton, the Beckler Peak stock, is a late Cretaceous tonalitic stock, with biotite and amphibole K-Ar ages of 93 to 82 Ma (Engels and Crowder, 1971, Yeats and Engels, 1971). The Beckler Peak stock is considered to be a companion body to the larger Mt. Stuart Batholith, but is separated from the Mt. Stuart Batholith by the Evergreen Fault. For this study five paleomagnetic sites were sampled from the Beckler Peak stock near Skykomish, Washington. After low temperature and thermal demagnetization site means were calculated for the four sites where at least two samples survived demagnetization. Unblocking temperatures were indicative of magnetite and hematite as the carriers of remanence. Two of the site means were disregarded due to anomalous directions likely due to sites being from very large slump blocks. The two acceptable site means, along with a Beckler Peak stock site mean from Beck and Noson (1972) and another from Housen et al. (2003) give a stock-wide mean of D = 3.8°, I = 41.9°, k = 32.9, and α95 = 16.2°. This direction is consistent with mean directions for the Mount Stuart batholith determined by Beck and Noson (1972), Beck et al. (1981), and Housen et al. (2003). This directional consistency supports an association between the Beckler Peak stock and the Mt. Stuart Batholith, or at least that these two plutonic bodies were emplaced in the same structural block, and that any post-magnetization deformation (such as rotation and/or tilt associated with the Evergreen Fault) between the Beckler Peak stock and the Mt. Stuart Batholith was minor.

  11. Predicting Nonlinear Site Response Using Spectral Acceleration Vs PGV/Vs30: A Case History Using the Volvi-Test Site

    NASA Astrophysics Data System (ADS)

    Guéguen, Philippe

    2015-12-01

    In this study, we analyze the efficiency of the ratio between particle velocity and shear wave velocity as a strain proxy for evaluating the nonlinear seismic response of sediments. The in situ stress-strain relationships are derived from accelerometric vertical array recordings at the TST site in Volvi (Thessaloniki, Greece). First, the shear wave velocity between two successive sensors was computed by seismic interferometry and strain was computed as the velocity ratio or the relative displacement between sensors. The shear-wave velocity profile and in situ shear modulus degradation curve with strain were compared with previous studies performed at the TST site. Finally, the stress-strain relationships were derived from data recorded at the surface by extending the strain proxy and stress values to the ratio between peak ground velocity and the Vs30 parameter used for site classification, i.e. without requiring the accelerometric vertical array. Our model captures the in situ nonlinear response of the site, without consideration of azimuth or distance of the earthquakes. In conclusion, the acceleration (stress) values, based on the accelerometric response spectra instead of peak ground acceleration compared with the deformation (strain) proxy, provide an effective model of the in situ nonlinear response, providing information that can be integrated into ground motion prediction equations.

  12. Predicting Nonlinear Site Response Using Spectral Acceleration Vs PGV/Vs30: A Case History Using the Volvi-Test Site

    NASA Astrophysics Data System (ADS)

    Guéguen, Philippe

    2016-06-01

    In this study, we analyze the efficiency of the ratio between particle velocity and shear wave velocity as a strain proxy for evaluating the nonlinear seismic response of sediments. The in situ stress-strain relationships are derived from accelerometric vertical array recordings at the TST site in Volvi (Thessaloniki, Greece). First, the shear wave velocity between two successive sensors was computed by seismic interferometry and strain was computed as the velocity ratio or the relative displacement between sensors. The shear-wave velocity profile and in situ shear modulus degradation curve with strain were compared with previous studies performed at the TST site. Finally, the stress-strain relationships were derived from data recorded at the surface by extending the strain proxy and stress values to the ratio between peak ground velocity and the Vs30 parameter used for site classification, i.e. without requiring the accelerometric vertical array. Our model captures the in situ nonlinear response of the site, without consideration of azimuth or distance of the earthquakes. In conclusion, the acceleration (stress) values, based on the accelerometric response spectra instead of peak ground acceleration compared with the deformation (strain) proxy, provide an effective model of the in situ nonlinear response, providing information that can be integrated into ground motion prediction equations.

  13. MOSES AND DENNISON PEAK ROADLESS AREAS, CALIFORNIA.

    USGS Publications Warehouse

    Goldfarb, Richard J.; Lipton, David A.

    1984-01-01

    A mineral-resource survey was conducted in the Moses and Dennison Peak Roadless Areas, southeastern Sierra Nevada, California. One area within the Moses Roadless Area is classified as having substantiated mineral-resource potential for small base-metal skarn deposits. Additionally, geochemical data indicate probable potential for small base-metal skarn deposits from one locality within Dennison Peak Roadless Area and for small tungsten skarn deposits from a region within Moses Roadless Area. The geologic setting precludes the presence of energy resources.

  14. Estimation of seismic ground motions using deterministic approach for major cities of Gujarat

    NASA Astrophysics Data System (ADS)

    Shukla, J.; Choudhury, D.

    2012-06-01

    A deterministic seismic hazard analysis has been carried out for various sites of the major cities (Ahmedabad, Surat, Bhuj, Jamnagar and Junagadh) of the Gujarat region in India to compute the seismic hazard exceeding a certain level in terms of peak ground acceleration (PGA) and to estimate maximum possible PGA at each site at bed rock level. The seismic sources in Gujarat are very uncertain and recurrence intervals of regional large earthquakes are not well defined. Because the instrumental records of India specifically in the Gujarat region are far from being satisfactory for modeling the seismic hazard using the probabilistic approach, an attempt has been made in this study to accomplish it through the deterministic approach. In this regard, all small and large faults of the Gujarat region were evaluated to obtain major fault systems. The empirical relations suggested by earlier researchers for the estimation of maximum magnitude of earthquake motion with various properties of faults like length, surface area, slip rate, etc. have been applied to those faults to obtain the maximum earthquake magnitude. For the analysis, seven different ground motion attenuation relations (GMARs) of strong ground motion have been utilized to calculate the maximum horizontal ground accelerations for each major city of Gujarat. Epistemic uncertainties in the hazard computations are accounted for within a logic-tree framework by considering the controlling parameters like b-value, maximum magnitude and ground motion attenuation relations (GMARs). The corresponding deterministic spectra have been prepared for each major city for the 50th and 84th percentiles of ground motion occurrence. These deterministic spectra are further compared with the specified spectra of Indian design code IS:1893-Part I (2002) to validate them for further practical use. Close examination of the developed spectra reveals that the expected ground motion values become high for the Kachchh region i.e. Bhuj

  15. Probabilistic sensitivity analysis of two suspension bridges in Istanbul, Turkey to near- and far-fault ground motion

    NASA Astrophysics Data System (ADS)

    Çavdar, Ö.

    2012-02-01

    The aim of this paper is to compare the near-fault and far-fault ground motion effects on the probabilistic sensitivity dynamic responses of two suspension bridges in Istanbul. Two different types of suspension bridges are selected to investigate the near-fault (NF) and far-fault (FF) ground motion effects on the bridge sensitivity responses. NF and FF strong ground motion records, which have approximately identical peak ground accelerations, of the Kocaeli (1999) earthquake are selected for the analyses. Displacements and internal forces are determined using the probabilistic sensitivity method (PSM), which is one type of stochastic finite element method. The efficiency and accuracy of the proposed algorithm are validated by comparison with results of the Monte Carlo Simulation (MCS) method. The displacements and internal forces obtained from the analyses of suspension bridges subjected to each fault effect are compared with each other. It is clearly seen that there is more seismic demand on displacements and internal forces when suspension bridges are subjected to NF and FF ground motion.

  16. Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator

    NASA Astrophysics Data System (ADS)

    Hiratsuka, Junichi; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Miyamoto, Kenji; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki

    2016-02-01

    To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ˜16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles.

  17. Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator.

    PubMed

    Hiratsuka, Junichi; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Miyamoto, Kenji; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki

    2016-02-01

    To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles. PMID:26932019

  18. Analysis of strong ground motions and site effects at Kantipath, Kathmandu, from 2015 Mw 7.8 Gorkha, Nepal, earthquake and its aftershocks

    NASA Astrophysics Data System (ADS)

    Dhakal, Yadab P.; Kubo, Hisahiko; Suzuki, Wataru; Kunugi, Takashi; Aoi, Shin; Fujiwara, Hiroyuki

    2016-04-01

    Strong ground motions from the 2015 Mw 7.8 Gorkha, Nepal, earthquake and its eight aftershocks recorded by a strong-motion seismograph at Kantipath (KATNP), Kathmandu, were analyzed to assess the ground-motion characteristics and site effects at this location. Remarkably large elastic pseudo-velocity responses exceeding 300 cm/s at 5 % critical damping were calculated for the horizontal components of the mainshock recordings at peak periods of 4-5 s. Conversely, the short-period ground motions of the mainshock were relatively weak despite the proximity of the site to the source fault. The horizontal components of all large-magnitude (Mw ≥ 6.3) aftershock recordings showed peak pseudo-velocity responses at periods of 3-4 s. Ground-motion prediction equations (GMPEs) describing the Nepal Himalaya region have not yet been developed. A comparison of the observational data with GMPEs for Japan showed that with the exception of the peak ground acceleration (PGA) of the mainshock, the observed PGAs and peak ground velocities at the KATNP site are generally well described by the GMPEs for crustal and plate interface events. A comparison of the horizontal-to-vertical ( H/ V) spectral ratios for the S-waves of the mainshock and aftershock recordings suggested that the KATNP site experienced a considerable nonlinear site response, which resulted in the reduced amplitudes of short-period ground motions. The GMPEs were found to underestimate the response values at the peak periods (approximately 4-5 s) of the large-magnitude events. The deep subsurface velocity model of the Kathmandu basin has not been well investigated. Therefore, a one-dimensional velocity model was constructed for the deep sediments beneath the recording station based on an analysis of the H/ V spectral ratios for S-wave coda from aftershock recordings, and it was revealed that the basin sediments strongly amplified the long-period components of the ground motions of the mainshock and large

  19. Ground-motion prediction equations for the average horizontal component of PGA, PGV, and 5%-damped PSA at spectral periods between 0.01 s and 10.0 s

    USGS Publications Warehouse

    Boore, D.M.; Atkinson, G.M.

    2008-01-01

    This paper contains ground-motion prediction equations (GMPEs) for average horizontal-component ground motions as a function of earthquake magnitude, distance from source to site, local average shear-wave velocity, and fault type. Our equations are for peak ground acceleration (PGA), peak ground velocity (PGV), and 5%-damped pseudo-absolute-acceleration spectra (PSA) at periods between 0.01 s and 10 s. They were derived by empirical regression of an extensive strong-motion database compiled by the 'PEER NGA' (Pacific Earthquake Engineering Research Center's Next Generation Attenuation) project. For periods less than 1 s, the analysis used 1,574 records from 58 mainshocks in the distance range from 0 km to 400 km (the number of available data decreased as period increased). The primary predictor variables are moment magnitude (M), closest horizontal distance to the surface projection of the fault plane (RJB), and the time-averaged shear-wave velocity from the surface to 30 m (VS30). The equations are applicable for M=5-8, RJB<200 km, and VS30= 180-1300 m/s. ?? 2008, Earthquake Engineering Research Institute.

  20. Peak Wind Tool for General Forecasting

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III; Short, David

    2008-01-01

    This report describes work done by the Applied Meteorology Unit (AMU) in predicting peak winds at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45th Weather Squadron requested the AMU develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. Based on observations from the KSC/CCAFS wind tower network , Shuttle Landing Facility (SLF) surface observations, and CCAFS sounding s from the cool season months of October 2002 to February 2007, the AMU created mul tiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence , the temperature inversion depth and strength, wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft.

  1. Absorption, Creativity, Peak Experiences, Empathy, and Psychoticism.

    ERIC Educational Resources Information Center

    Mathes, Eugene W.; And Others

    Tellegen and Atkinson suggested that the trait of absorption may play a part in meditative skill, creativity, capacity for peak experiences, and empathy. Although the absorption-meditative skill relationship has been confirmed, other predictions have not been tested. Tellegen and Atkinson's Absorption Scale was completed by undergraduates in four…

  2. Six Ways To Foster Peak Performance.

    ERIC Educational Resources Information Center

    Sevilla, Christine; Wells, Timothy D.

    1999-01-01

    Discusses six initiatives that organizations can support to ensure peak performance: individual knowledge portfolios; mentoring and apprenticeship relationships; electronic conferencing systems; organizational knowledge repository; community of practice; reward and recognition. Defines each initiative and describes how to make each one work in an…

  3. Avoiding the False Peaks in Correlation Discrimination

    SciTech Connect

    Awwal, A S

    2009-07-31

    Fiducials imprinted on laser beams are used to perform video image based alignment of the 192 laser beams in the National Ignition Facility (NIF) of Lawrence Livermore National Laboratory. In many video images, matched filtering is used to detect the location of these fiducials. Generally, the highest correlation peak is used to determine the position of the fiducials. However, when the signal to-be-detected is very weak compared to the noise, this approach totally breaks down. The highest peaks act as traps for false detection. The active target images used for automatic alignment in the National Ignition Facility are examples of such images. In these images, the fiducials of interest exhibit extremely low intensity and contrast, surrounded by high intensity reflection from metallic objects. Consequently, the highest correlation peaks are caused by these bright objects. In this work, we show how the shape of the correlation is exploited to isolate the valid matches from hundreds of invalid correlation peaks, and therefore identify extremely faint fiducials under very challenging imaging conditions.

  4. Hubbert's Peak: the Impending World oil Shortage

    NASA Astrophysics Data System (ADS)

    Deffeyes, K. S.

    2004-12-01

    Global oil production will probably reach a peak sometime during this decade. After the peak, the world's production of crude oil will fall, never to rise again. The world will not run out of energy, but developing alternative energy sources on a large scale will take at least 10 years. The slowdown in oil production may already be beginning; the current price fluctuations for crude oil and natural gas may be the preamble to a major crisis. In 1956, the geologist M. King Hubbert predicted that U.S. oil production would peak in the early 1970s.1 Almost everyone, inside and outside the oil industry, rejected Hubbert's analysis. The controversy raged until 1970, when the U.S. production of crude oil started to fall. Hubbert was right. Around 1995, several analysts began applying Hubbert's method to world oil production, and most of them estimate that the peak year for world oil will be between 2004 and 2008. These analyses were reported in some of the most widely circulated sources: Nature, Science, and Scientific American.2 None of our political leaders seem to be paying attention. If the predictions are correct, there will be enormous effects on the world economy. Even the poorest nations need fuel to run irrigation pumps. The industrialized nations will be bidding against one another for the dwindling oil supply. The good news is that we will put less carbon dioxide into the atmosphere. The bad news is that my pickup truck has a 25-gallon tank.

  5. Peak structural response to nonstationary random excitations

    NASA Technical Reports Server (NTRS)

    Shinozuka, M.; Yang, J.-N.

    1971-01-01

    Study establishes distribution function of peak response values, based on frequency interpretation. Excitations considered include impact loading on landing gears and aircraft gust loading. Because of relative severity of excitations, prediction of fatigue and maximum response characteristics is important part of task of structural analysis and design.

  6. Double-peak subauroral ion drifts (DSAIDs)

    NASA Astrophysics Data System (ADS)

    He, Fei; Zhang, Xiao-Xin; Wang, Wenbin; Chen, Bo

    2016-06-01

    This paper reports double-peak subauroral ion drifts (DSAIDs), which is unique subset of subauroral ion drifts (SAIDs). A statistical analysis has been carried out for the first time with a database of 454 DSAID events identified from Defense Meteorological Satellite Program observations from 1987 to 2012. Both case studies and statistical analyses show that the two velocity peaks of DSAIDs are associated with two ion temperature peaks and two region-2 field-aligned currents (R2-FACs) peaks in the midlatitude ionospheric trough located in the low-conductance subauroral region. DSAIDs are regional and vary significantly with magnetic local time. DSAIDs can evolve from/to SAIDs during their lifetimes, which are from several minutes to tens of minutes. Comparisons between the ionospheric parameters of DSAIDs and SAIDs indicate that double-layer region-2 field-aligned currents (R2-FACs) may be the main driver of DSAIDs. It is also found that DSAIDs happen during more disturbed conditions compared with SAIDs.

  7. Joint kinematics and kinetics of overground accelerated running versus running on an accelerated treadmill

    PubMed Central

    Van Caekenberghe, Ine; Segers, Veerle; Aerts, Peter; Willems, Patrick; De Clercq, Dirk

    2013-01-01

    Literature shows that running on an accelerated motorized treadmill is mechanically different from accelerated running overground. Overground, the subject has to enlarge the net anterior–posterior force impulse proportional to acceleration in order to overcome linear whole body inertia, whereas on a treadmill, this force impulse remains zero, regardless of belt acceleration. Therefore, it can be expected that changes in kinematics and joint kinetics of the human body also are proportional to acceleration overground, whereas no changes according to belt acceleration are expected on a treadmill. This study documents kinematics and joint kinetics of accelerated running overground and running on an accelerated motorized treadmill belt for 10 young healthy subjects. When accelerating overground, ground reaction forces are characterized by less braking and more propulsion, generating a more forward-oriented ground reaction force vector and a more forwardly inclined body compared with steady-state running. This change in body orientation as such is partly responsible for the changed force direction. Besides this, more pronounced hip and knee flexion at initial contact, a larger hip extension velocity, smaller knee flexion velocity and smaller initial plantarflexion velocity are associated with less braking. A larger knee extension and plantarflexion velocity result in larger propulsion. Altogether, during stance, joint moments are not significantly influenced by acceleration overground. Therefore, we suggest that the overall behaviour of the musculoskeletal system (in terms of kinematics and joint moments) during acceleration at a certain speed remains essentially identical to steady-state running at the same speed, yet acting in a different orientation. However, because acceleration implies extra mechanical work to increase the running speed, muscular effort done (in terms of power output) must be larger. This is confirmed by larger joint power generation at the level

  8. Spanish Peaks, Sangre de Cristo Range, Colorado

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Spanish Peaks, on the eastern flank of the Sangre de Cristo range, abruptly rise 7,000 feet above the western Great Plains. Settlers, treasure hunters, trappers, gold and silver miners have long sighted on these prominent landmarks along the Taos branch of the Santa Fe trail. Well before the westward migration, the mountains figured in the legends and history of the Ute, Apache, Comanche, and earlier tribes. 'Las Cumbres Espanolas' are also mentioned in chronicles of exploration by Spaniards including Ulibarri in 1706 and later by de Anza, who eventually founded San Francisco (California). This exceptional view (STS108-720-32), captured by the crew of Space Shuttle mission STS108, portrays the Spanish Peaks in the context of the southern Rocky Mountains. Uplift of the Sangre de Cristo began about 75 million years ago and produced the long north-trending ridges of faulted and folded rock to the west of the paired peaks. After uplift had ceased (26 to 22 million years ago), the large masses of igneous rock (granite, granodiorite, syenodiorite) that form the Peaks were emplaced (Penn, 1995-2001). East and West Spanish Peaks are 'stocks'-bodies of molten rock that intruded sedimentary layers, cooled and solidified, and were later exposed by erosion. East Peak (E), at 12,708 ft is almost circular and is about 5 1/2 miles long by 3 miles wide, while West Peak (W), at 13,623 ft is roughly 2 3/4 miles long by 1 3/4 miles wide. Great dikes-long stone walls-radiate outward from the mountains like spokes of a wheel, a prominent one forms a broad arc northeast of East Spanish Peak. As the molten rock rose, it forced its way into vertical cracks and joints in the sedimentary strata; the less resistant material was then eroded away, leaving walls of hard rock from 1 foot to 100 feet wide, up to 100 feet high, and as long as 14 miles. Dikes trending almost east-west are also common in the region. For more information visit: Sangres.com: The Spanish Peaks (accessed January 16

  9. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2006-04-18

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  10. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2005-06-14

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  11. Analysis of ground response data at Lotung large-scale soil- structure interaction experiment site. Final report

    SciTech Connect

    Chang, C.Y.; Mok, C.M.; Power, M.S.

    1991-12-01

    The Electric Power Research Institute (EPRI), in cooperation with the Taiwan Power Company (TPC), constructed two models (1/4-scale and 1/2-scale) of a nuclear plant containment structure at a site in Lotung (Tang, 1987), a seismically active region in northeast Taiwan. The models were constructed to gather data for the evaluation and validation of soil-structure interaction (SSI) analysis methodologies. Extensive instrumentation was deployed to record both structural and ground responses at the site during earthquakes. The experiment is generally referred to as the Lotung Large-Scale Seismic Test (LSST). As part of the LSST, two downhole arrays were installed at the site to record ground motions at depths as well as at the ground surface. Structural response and ground response have been recorded for a number of earthquakes (i.e. a total of 18 earthquakes in the period of October 1985 through November 1986) at the LSST site since the completion of the installation of the downhole instruments in October 1985. These data include those from earthquakes having magnitudes ranging from M{sub L} 4.5 to M{sub L} 7.0 and epicentral distances range from 4.7 km to 77.7 km. Peak ground surface accelerations range from 0.03 g to 0.21 g for the horizontal component and from 0.01 g to 0.20 g for the vertical component. The objectives of the study were: (1) to obtain empirical data on variations of earthquake ground motion with depth; (2) to examine field evidence of nonlinear soil response due to earthquake shaking and to determine the degree of soil nonlinearity; (3) to assess the ability of ground response analysis techniques including techniques to approximate nonlinear soil response to estimate ground motions due to earthquake shaking; and (4) to analyze earth pressures recorded beneath the basemat and on the side wall of the 1/4 scale model structure during selected earthquakes.

  12. The spatial resolution of epidemic peaks.

    PubMed

    Mills, Harriet L; Riley, Steven

    2014-04-01

    The emergence of novel respiratory pathogens can challenge the capacity of key health care resources, such as intensive care units, that are constrained to serve only specific geographical populations. An ability to predict the magnitude and timing of peak incidence at the scale of a single large population would help to accurately assess the value of interventions designed to reduce that peak. However, current disease-dynamic theory does not provide a clear understanding of the relationship between: epidemic trajectories at the scale of interest (e.g. city); population mobility; and higher resolution spatial effects (e.g. transmission within small neighbourhoods). Here, we used a spatially-explicit stochastic meta-population model of arbitrary spatial resolution to determine the effect of resolution on model-derived epidemic trajectories. We simulated an influenza-like pathogen spreading across theoretical and actual population densities and varied our assumptions about mobility using Latin-Hypercube sampling. Even though, by design, cumulative attack rates were the same for all resolutions and mobilities, peak incidences were different. Clear thresholds existed for all tested populations, such that models with resolutions lower than the threshold substantially overestimated population-wide peak incidence. The effect of resolution was most important in populations which were of lower density and lower mobility. With the expectation of accurate spatial incidence datasets in the near future, our objective was to provide a framework for how to use these data correctly in a spatial meta-population model. Our results suggest that there is a fundamental spatial resolution for any pathogen-population pair. If underlying interactions between pathogens and spatially heterogeneous populations are represented at this resolution or higher, accurate predictions of peak incidence for city-scale epidemics are feasible. PMID:24722420

  13. A Study of Site Effect on Strong Ground Motion Characteristics in Ilan, Taiwan

    NASA Astrophysics Data System (ADS)

    Liu, K.; Taiwan Earthquake Research Center

    2010-12-01

    An evaluation of seismic hazards requires an estimate of the expected ground motion at the site of interest. The most common means of estimating this ground motion in engineering practice is the use of an attenuation relation. Numerous attenuation relationships have been developed over the years by different seismologists and engineers, each using different data sets and assumptions regarding the most appropriate functional form. A number of developments have arisen recently to suggest that a new generation of attenuation relationships is warranted. Site effects play a very important role in characterizing seismic motions because they may strongly amplify seismic motions at the last moment just before reaching the surface of the ground. Examination of the residuals for sites with different soil categories is a useful method for sets of records in which site information is not complete, and hence cannot be included explicitly within the equation. We derive the spectra acceleration of periods 0.1,0.2,1.0,2.0 and 3.0 sec according to the Next Generation Attenuation of Ground Motions (NGA) Project which were developed by Pacific Earthquake Engineering Research Center. From the site residuals for SA data, we further to obtain the site effect factor of the above periods in Taiwan area. In addition, we estimate the seismic hazard potential in Taiwan in the form of ShakeMap. In this study, the site response factor is incorporated in the present ground motion prediction models. Such prediction models will result in more realistic peak ground motion estimates for assessment of seismic hazard potential. These results provide an important database for the site evaluation of critical facilities in those relatively high earthquake hazard potential regions and will be helpful for the plan of land-using.

  14. A study of possible ground-motion amplification at the Coyote Lake Dam, California

    USGS Publications Warehouse

    Boore, D.M.; Graizer, V.M.; Tinsley, J.C.; Shakal, A.F.

    2004-01-01

    The abutment site at the Coyote Lake Dam recorded an unusually large peak acceleration of 1.29g during the 1984 Morgan Hill earthquake. Following this earthquake another strong-motion station was installed about 700 m downstream from the abutment station. We study all events (seven) recorded on these stations, using ratios of peak accelerations, spectral ratios, and particle motion polarization (using holograms) to investigate the relative ground motion at the two sites. We find that in all but one case the motion at the abutment site is larger than the downstream site over a broad frequency band. The polarizations are similar for the two sites for a given event, but can vary from one event to another. This suggests that the dam itself is not strongly influencing the records. Although we can be sure that the relative motion is usually larger at the abutment site, we cannot conclude that there is anomalous site amplification at the abutment site. The downstream site could have lower-than-usual near-surface amplifications. On the other hand, the geology near the abutment site is extremely complex and includes fault slivers, with rapid lateral changes in materials and presumably seismic velocities. For this reason alone, the abutment site should not be considered a normal free-field site.

  15. Particle acceleration by combined diffusive shock acceleration and downstream multiple magnetic island acceleration

    NASA Astrophysics Data System (ADS)

    Zank, G. P.; Hunana, P.; Mostafavi, P.; le Roux, J. A.; Li, Gang; Webb, G. M.; Khabarova, O.

    2015-09-01

    As a consequence of the evolutionary conditions [28; 29], shock waves can generate high levels of downstream vortical turbulence. Simulations [32-34] and observations [30; 31] support the idea that downstream magnetic islands (also called plasmoids or flux ropes) result from the interaction of shocks with upstream turbulence. Zank et al. [18] speculated that a combination of diffusive shock acceleration (DSA) and downstream reconnection-related effects associated with the dynamical evolution of a “sea of magnetic islands” would result in the energization of charged particles. Here, we utilize the transport theory [18; 19] for charged particles propagating diffusively in a turbulent region filled with contracting and reconnecting plasmoids and small-scale current sheets to investigate a combined DSA and downstream multiple magnetic island charged particle acceleration mechanism. We consider separately the effects of the anti-reconnection electric field that is a consequence of magnetic island merging [17], and magnetic island contraction [14]. For the merging plasmoid reconnection- induced electric field only, we find i) that the particle spectrum is a power law in particle speed, flatter than that derived from conventional DSA theory, and ii) that the solution is constant downstream of the shock. For downstream plasmoid contraction only, we find that i) the accelerated particle spectrum is a power law in particle speed, flatter than that derived from conventional DSA theory; ii) for a given energy, the particle intensity peaks downstream of the shock, and the peak location occurs further downstream of the shock with increasing particle energy, and iii) the particle intensity amplification for a particular particle energy, f(x, c/c0)/f(0, c/c0), is not 1, as predicted by DSA theory, but increases with increasing particle energy. These predictions can be tested against observations of electrons and ions accelerated at interplanetary shocks and the heliospheric

  16. 6.9 Sikkim Earthquake and Modeling of Ground Motions to Determine Causative Fault

    NASA Astrophysics Data System (ADS)

    Chopra, Sumer; Sharma, Jyoti; Sutar, Anup; Bansal, B. K.

    2014-07-01

    In this study, source parameters of the September 18, 2011 M w 6.9, Sikkim earthquake were determined using acceleration records. These parameters were then used to generate strong motion at a number of sites using the stochastic finite fault modeling technique to constrain the causative fault plane for this earthquake. The average values of corner frequency, seismic moment, stress drop and source radius were 0.12 Hz, 3.07 × 1026 dyne-cm, 115 bars and 9.68 km, respectively. The fault plane solution showed strike-slip movement with two nodal planes oriented along two prominent lineaments in the region, the NE-oriented Kanchendzonga and NW-oriented Tista lineaments. The ground motions were estimated considering both the nodal planes as causative faults and the results in terms of the peak ground accelerations (PGA) and Fourier spectra were then compared with the actual recordings. We found that the NW-SE striking nodal plane along the Tista lineament may have been the causative fault for the Sikkim earthquake, as PGA estimates are comparable with the observed recordings. We also observed that the Fourier spectrum is not a good parameter in deciding the causative fault plane.

  17. On the Relationship between Fourier and Response Spectra: Implications for the Adjustment of Empirical Ground-Motion Prediction Equations (GMPEs)

    NASA Astrophysics Data System (ADS)

    Bora, Sanjay; Scherbaum, Frank; Kuehn, Nicolas; Stafford, Peter

    2016-04-01

    oscillator-frequency response spectral ordinates are controlled by a rather wide-band of Fourier spectral ordinates. In fact, the peak ground acceleration (PGA), counter to the popular perception that it is a reflection of the high-frequency characteristics of ground motion, is controlled by the entire Fourier spectrum of ground-motion. Finally, it is demonstrated, how an adjustment made in Fourier spectral amplitudes is different or similar to the same adjustment made in the response spectral amplitudes. For this purpose, two cases: adjustments to the stress parameter (Δσ) (source term) and to attributes reflecting site response (V s-κ0) are considered.

  18. Discrete ordinates transport methods for problems with highly forward-peaked scattering

    SciTech Connect

    Pautz, S.D.

    1998-04-01

    The author examines the solutions of the discrete ordinates (S{sub N}) method for problems with highly forward-peaked scattering kernels. He derives conditions necessary to obtain reasonable solutions in a certain forward-peaked limit, the Fokker-Planck (FP) limit. He also analyzes the acceleration of the iterative solution of such problems and offer improvements to it. He extends the analytic Fokker-Planck limit analysis to the S{sub N} equations. This analysis shows that in this asymptotic limit the S{sub N} solution satisfies a pseudospectral discretization of the FP equation, provided that the scattering term is handled in a certain way (which he describes) and that the analytic transport solution satisfies an analytic FP equation. Similar analyses of various spatially discretized S{sub N} equations reveal that they too produce solutions that satisfy discrete FP equations, given the same provisions. Numerical results agree with these theoretical predictions. He defines a multidimensional angular multigrid (ANMG) method to accelerate the iterative solution of highly forward-peaked problems. The analyses show that a straightforward application of this scheme is subject to high-frequency instabilities. However, by applying a diffusive filter to the ANMG corrections he is able to stabilize this method. Fourier analyses of model problems show that the resulting method is effective at accelerating the convergence rate when the scattering is forward-peaked. The numerical results demonstrate that these analyses are good predictors of the actual performance of the ANMG method.

  19. FDTD simulation of LEMP propagation over lossy ground: Influence of distance, ground conductivity, and source parameters

    NASA Astrophysics Data System (ADS)

    Aoki, Masanori; Baba, Yoshihiro; Rakov, Vladimir A.

    2015-08-01

    We have computed lightning electromagnetic pulses (LEMPs), including the azimuthal magnetic field Hφ, vertical electric field Ez, and horizontal (radial) electric field Eh that propagated over 5 to 200 km of flat lossy ground, using the finite difference time domain (FDTD) method in the 2-D cylindrical coordinate system. This is the first systematic full-wave study of LEMP propagation effects based on a realistic return-stroke model and including the complete return-stroke frequency range. Influences of the return-stroke wavefront speed (ranging from c/2 to c, where c is the speed of light), current risetime (ranging from 0.5 to 5 µs), and ground conductivity (ranging from 0.1 mS/m to ∞) on Hφ, Ez, and Eh have been investigated. Also, the FDTD-computed waveforms of Eh have been compared with the corresponding ones computed using the Cooray-Rubinstein formula. Peaks of Hφ, Ez, and Eh are nearly proportional to the return-stroke wavefront speed. The peak of Eh decreases with increasing current risetime, while those of Hφ and Ez are only slightly influenced by it. The peaks of Hφ and Ez are essentially independent of the ground conductivity at a distance of 5 km. Beyond this distance, they appreciably decrease relative to the perfectly conducting ground case, and the decrease is stronger for lower ground conductivity values. The peak of Eh increases with decreasing ground conductivity. The computed Eh/Ez is consistent with measurements of Thomson et al. (1988). The observed decrease of Ez peak and increase of Ez risetime due to propagation over 200 km of Florida soil are reasonably well reproduced by the FDTD simulation with ground conductivity of 1 mS/m.

  20. To examine the association between oscillations of the stratospheric aerosol layer peaks and different types of clouds

    NASA Astrophysics Data System (ADS)

    Mane, P. B.

    2014-11-01

    Aerosol measurements have been carried out at Kolhapur (16°42'N, 74°14'E) by using newly designed Semiautomatic Twilight Photometer. The system is a ground based simple and inexpensive but very sensitive passive remote sensing technique. The altitudes of the Junge layer peaks on measurement days were derived from the aerosol vertical profiles. One attempt is made to examine the association between oscillations of the stratospheric aerosol layer peaks and different types of clouds. The values of AND for the Junge layer peaks for each observational day were also calculated. The graph between AND at peak point of Junge layer and day numbers was also studied in comparison with High, Medium and Low level clouds. There is an annual variation in the altitude of the peak of Junge layer also. Its maximum is observed during January. The annual variation of the altitude of the peak of Junge layer and the AND of Junge layer peak showed opposite phase relation.

  1. Dynamic Tire Pressure Sensor for Measuring Ground Vibration

    PubMed Central

    Wang, Qi; McDaniel, James Gregory; Wang, Ming L.

    2012-01-01

    This work presents a convenient and non-contact acoustic sensing approach for measuring ground vibration. This approach, which uses an instantaneous dynamic tire pressure sensor (DTPS), possesses the capability to replace the accelerometer or directional microphone currently being used for inspecting pavement conditions. By measuring dynamic pressure changes inside the tire, ground vibration can be amplified and isolated from environmental noise. In this work, verifications of the DTPS concept of sensing inside the tire have been carried out. In addition, comparisons between a DTPS, ground-mounted accelerometer, and directional microphone are made. A data analysis algorithm has been developed and optimized to reconstruct ground acceleration from DTPS data. Numerical and experimental studies of this DTPS reveal a strong potential for measuring ground vibration caused by a moving vehicle. A calibration of transfer function between dynamic tire pressure change and ground acceleration may be needed for different tire system or for more accurate application. PMID:23202206

  2. Dynamic tire pressure sensor for measuring ground vibration.

    PubMed

    Wang, Qi; McDaniel, James Gregory; Wang, Ming L

    2012-01-01

    This work presents a convenient and non-contact acoustic sensing approach for measuring ground vibration. This approach, which uses an instantaneous dynamic tire pressure sensor (DTPS), possesses the capability to replace the accelerometer or directional microphone currently being used for inspecting pavement conditions. By measuring dynamic pressure changes inside the tire, ground vibration can be amplified and isolated from environmental noise. In this work, verifications of the DTPS concept of sensing inside the tire have been carried out. In addition, comparisons between a DTPS, ground-mounted accelerometer, and directional microphone are made. A data analysis algorithm has been developed and optimized to reconstruct ground acceleration from DTPS data. Numerical and experimental studies of this DTPS reveal a strong potential for measuring ground vibration caused by a moving vehicle. A calibration of transfer function between dynamic tire pressure change and ground acceleration may be needed for different tire system or for more accurate application. PMID:23202206

  3. Geochemical clues on the origin of the current accelerating deformation of Campi Flegrei caldera

    NASA Astrophysics Data System (ADS)

    Chiodini, Giovanni

    2016-04-01

    An accelerating process of ground deformation is currently affecting the Campi Flegrei caldera. The deformation pattern is here explained with the overlapping of two processes: short time pulses that are caused by injection of magmatic fluids into the hydrothermal system, and a longer time process of heating of the rock. The short pulses were highlighted by comparing fumarolic compositions and ground deformations. The two independent data sets show the same sequence of anomalous peaks with a delay of ˜ 200 days of the geochemical signal with respect to the geodetic signal. This correspondence strongly support the occurrence of episodes of magmatic fluid injection into the hydrothermal system feeding the fumaroles of Solfatara. Seismic swarms, whose frequency is increasing in the time, accompanies each of this episode. The heating of the hydrothermal system, which parallels the long-period accelerating curve, is inferred by temperature-pressure gas geoindicators. Referring to a recent interpretation that relates variations in the fumarolic inert gas species to open system magma degassing, we infer that the heating is caused by an enrichment in water of the magmatic fluids, in addition to an increment in their flux and an increased frequency of the degassing events. A physical numerical model of the injection of magmatic fluids into the hydrothermal system nicely reproduces many of the observed data including the thermal evolution independently inferred from the fumarolic composition.

  4. Accelerating momentum for change!

    PubMed

    Wenzel, S; Panetta, J

    1995-05-01

    As we develop strategies to compete globally, we are challenged with integrating our resources to execute these strategies effectively. Many companies are in the midst of dramatic shifts in corporate cultures, giving more responsibility to employees while raising expectations for their performance. The extent of these changes is far reaching and brings significant challenges to both employees and corporations. This article is a continuation of the evolution (over five years) of a corrective action/continuous improvement process implemented at Exide Electronics. It discusses organizational structures, including steering committees, corrective action teams, task teams, and work cells. Specific expectations, goals, and results of the teams are presented, along with ground rules for functioning within the organization. After structuring the organization and coordinating the resources effectively, the next challenge is accelerating momentum for change. The presentation also discusses the evolutionary process required to make a culture focused on change, including ongoing communication and feedback, constant evaluation and direction of the process, and measuring and paying for performance. PMID:10142097

  5. Predicting VO2peak from Submaximal- and Peak Exercise Models: The HUNT 3 Fitness Study, Norway

    PubMed Central

    Loe, Henrik; Nes, Bjarne M.; Wisløff, Ulrik

    2016-01-01

    Purpose Peak oxygen uptake (VO2peak) is seldom assessed in health care settings although being inversely linked to cardiovascular risk and all-cause mortality. The aim of this study was to develop VO2peak prediction models for men and women based on directly measured VO2peak from a large healthy population Methods VO2peak prediction models based on submaximal- and peak performance treadmill work were derived from multiple regression analysis. 4637 healthy men and women aged 20–90 years were included. Data splitting was used to generate validation and cross-validation samples. Results The accuracy for the peak performance models were 10.5% (SEE = 4.63 mL⋅kg-1⋅min-1) and 11.5% (SEE = 4.11 mL⋅kg-1⋅min-1) for men and women, respectively, with 75% and 72% of the variance explained. For the submaximal performance models accuracy were 14.1% (SEE = 6.24 mL⋅kg-1⋅min-1) and 14.4% (SEE = 5.17 mL⋅kg-1⋅min-1) for men and women, respectively, with 55% and 56% of the variance explained. The validation and cross-validation samples displayed SEE and variance explained in agreement with the total sample. Cross-classification between measured and predicted VO2peak accurately classified 91% of the participants within the correct or nearest quintile of measured VO2peak. Conclusion Judicious use of the exercise prediction models presented in this study offers valuable information in providing a fairly accurate assessment of VO2peak, which may be beneficial for risk stratification in health care settings. PMID:26794677

  6. Peak Oil, Food Systems, and Public Health

    PubMed Central

    Parker, Cindy L.; Kirschenmann, Frederick L.; Tinch, Jennifer; Lawrence, Robert S.

    2011-01-01

    Peak oil is the phenomenon whereby global oil supplies will peak, then decline, with extraction growing increasingly costly. Today's globalized industrial food system depends on oil for fueling farm machinery, producing pesticides, and transporting goods. Biofuels production links oil prices to food prices. We examined food system vulnerability to rising oil prices and the public health consequences. In the short term, high food prices harm food security and equity. Over time, high prices will force the entire food system to adapt. Strong preparation and advance investment may mitigate the extent of dislocation and hunger. Certain social and policy changes could smooth adaptation; public health has an essential role in promoting a proactive, smart, and equitable transition that increases resilience and enables adequate food for all. PMID:21778492

  7. 27 CFR 9.140 - Atlas Peak.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... miles to the highest point of an unnamed peak of 1268 feet elevation in section 12, T. 6 N., R. 4 W. on... 12 and 13, T. 7 N., R. 4 W. on the Yountville U.S.G.S. map; (10) Then following the section boundary... elevation, located in section 10, T. N., R. 4 W.; (12) Then northwest in a straight line approximately...

  8. 27 CFR 9.140 - Atlas Peak.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... miles to the highest point of an unnamed peak of 1268 feet elevation in section 12, T. 6 N., R. 4 W. on... 12 and 13, T. 7 N., R. 4 W. on the Yountville U.S.G.S. map; (10) Then following the section boundary... elevation, located in section 10, T. N., R. 4 W.; (12) Then northwest in a straight line approximately...

  9. Back-calculation of surface acceleration from penetration resistances at liquefied sites of 1956 Dunaharaszti earthquake, in Hungary

    NASA Astrophysics Data System (ADS)

    Bán, Zoltán; Győri, Erzsébet; Horváth, Tibor

    2015-04-01

    Liquefaction and paleoliquefaction studies are being used increasingly to interpret ground motion parameters (acceleration, magnitude, epicenter location) in regions that experience infrequent but damaging earthquakes. These are especially applicable where the most recent damaging earthquakes occurred prior to the development of ground motion instrumentation. In Hungary, a damaging earthquake of magnitude 5.6 occurred in Dunaharaszti in 1956. Its epicenter was located about 5 km from the southern boundary of Budapest. The quake caused serious damages in the epicentral area and in the southern districts of the capital. A Wiechert type seismometer was operated in Budapest 15-20 km from the epicenter but it saturated by the earthquake so instrumental information does not exist about the shaking strength. Ground accelerations caused by the event can be deduced only from the macroseismic intensity values and from the analogies of recent similar earthquakes where strong motion data exist. The epicentral area of Dunaharaszti earthquake was located along the Danube River. Sand boils were observed in some locations that indicated the occurrence of liquefaction. Because their exact locations were recorded at the time of the earthquake, geotechnical measurements could be performed. Therefore an alternative possibility to estimate shaking strength can be the back-analysis of liquefaction field data. Unlike the paleoliquefaction studies, in our case the source of the earthquake and the magnitude is known, our purpose was only to estimate the peak ground acceleration and acceleration-related parameters, such as Arias intensity. Back-calculation of surface acceleration was performed at two locations, where evidences of liquefaction had been observed after the earthquake. On both locations SPT and CPT measurements were carried out, and back-analysis from them was performed with different empirical methods. This allowed the assessment of the selected method's and the used in

  10. Revisiting Twomey's approximation for peak supersaturation

    NASA Astrophysics Data System (ADS)

    Shipway, B. J.

    2015-04-01

    Twomey's seminal 1959 paper provided lower and upper bound approximations to the estimation of peak supersaturation within an updraft and thus provides the first closed expression for the number of nucleated cloud droplets. The form of this approximation is simple, but provides a surprisingly good estimate and has subsequently been employed in more sophisticated treatments of nucleation parametrization. In the current paper, we revisit the lower bound approximation of Twomey and make a small adjustment that can be used to obtain a more accurate calculation of peak supersaturation under all potential aerosol loadings and thermodynamic conditions. In order to make full use of this improved approximation, the underlying integro-differential equation for supersaturation evolution and the condition for calculating peak supersaturation are examined. A simple rearrangement of the algebra allows for an expression to be written down that can then be solved with a single lookup table with only one independent variable for an underlying lognormal aerosol population. While multimodal aerosol with N different dispersion characteristics requires 2N+1 inputs to calculate the activation fraction, only N of these one-dimensional lookup tables are needed. No additional information is required in the lookup table to deal with additional chemical, physical or thermodynamic properties. The resulting implementation provides a relatively simple, yet computationally cheap, physically based parametrization of droplet nucleation for use in climate and Numerical Weather Prediction models.

  11. [Fast spectral modeling based on Voigt peaks].

    PubMed

    Li, Jin-rong; Dai, Lian-kui

    2012-03-01

    Indirect hard modeling (IHM) is a recently introduced method for quantitative spectral analysis, which was applied to the analysis of nonlinear relation between mixture spectrum and component concentration. In addition, IHM is an effectual technology for the analysis of components of mixture with molecular interactions and strongly overlapping bands. Before the establishment of regression model, IHM needs to model the measured spectrum as a sum of Voigt peaks. The precision of the spectral model has immediate impact on the accuracy of the regression model. A spectrum often includes dozens or even hundreds of Voigt peaks, which mean that spectral modeling is a optimization problem with high dimensionality in fact. So, large operation overhead is needed and the solution would not be numerically unique due to the ill-condition of the optimization problem. An improved spectral modeling method is presented in the present paper, which reduces the dimensionality of optimization problem by determining the overlapped peaks in spectrum. Experimental results show that the spectral modeling based on the new method is more accurate and needs much shorter running time than conventional method. PMID:22582612

  12. METing SUSY on the Z peak

    NASA Astrophysics Data System (ADS)

    Barenboim, G.; Bernabeu, J.; Mitsou, V. A.; Romero, E.; Vives, O.

    2016-02-01

    Recently the ATLAS experiment announced a 3 σ excess at the Z-peak consisting of 29 pairs of leptons together with two or more jets, ET^{miss} > 225 GeV and HT > 600 GeV, to be compared with 10.6 ± 3.2 expected lepton pairs in the Standard Model. No excess outside the Z-peak was observed. By trying to explain this signal with SUSY we find that only relatively light gluinos, m_{tilde{g}} ≲ 1.2 TeV, together with a heavy neutralino NLSP of m_{tilde{χ }} ≳ 400 GeV decaying predominantly to Z-boson plus a light gravitino, such that nearly every gluino produces at least one Z-boson in its decay chain, could reproduce the excess. We construct an explicit general gauge mediation model able to reproduce the observed signal overcoming all the experimental limits. Needless to say, more sophisticated models could also reproduce the signal, however, any model would have to exhibit the following features: light gluinos, or heavy particles with a strong production cross section, producing at least one Z-boson in its decay chain. The implications of our findings for the Run II at LHC with the scaling on the Z peak, as well as for the direct search of gluinos and other SUSY particles, are pointed out.

  13. Eyesight and the solar Wien peak

    NASA Astrophysics Data System (ADS)

    Overduin, James M.

    2003-03-01

    It is sometimes said that humans see best at yellow-green wavelengths because they have evolved under a Sun whose blackbody spectrum has a Wien peak in the green part of the spectrum. However, as a function of frequency, the solar blackbody spectrum peaks in the infrared. Why did human vision not evolve toward a peak sensitivity in this range, if the eye is an efficient quantum detector of photons? The puzzle is resolved if we assume that natural selection acted in such a way as to maximize the amount of energy that can be detected by the retina across a range of wavelengths (whose upper and lower limits are fixed by biological constraints). It is then found that our eyes are indeed perfectly adapted to life under a class G2 star. Extending this reasoning allows educated guesses to be made about the kind of eyesight that might have evolved in extrasolar planetary systems such as that of the red dwarf Gliese 876.

  14. A stochastic estimate of ground motion at Oceano, California, for the M 6.5 22 December 2003 San Simeon earthquake, derived from aftershock recordings

    USGS Publications Warehouse

    Di, Alessandro C.; Boatwright, J.

    2006-01-01

    The U.S. Geological Survey deployed a digital seismic station in Oceano, California, in February 2004, to investigate the cause of damage and liquefaction from the 22 December 2003 M 6.5 San Simeon earthquake. This station recorded 11 M > 2.8 aftershocks in almost 8 weeks. We analyze these recordings, together with recordings of the mainshock and the same aftershocks obtained from nearby stations in Park Hill and San Luis Obispo, to estimate the mainshock ground motion in Oceano. We estimate the Fourier amplitude spectrum using generalized spectral ratio analysis. We test a set of aftershocks as Green's functions by comparing simulated and recorded acceleration amplitude spectra for the mainshock at San Luis Obispo and Park Hill. We convolve the aftershock accelerograms with a stochastic operator to simulate the duration and phase of the mainshock accelerograms. This approximation allows us to extend the range of aftershocks that can be used as Green's functions to events nearly three magnitude units smaller than the mainshock. Our realizations for the mainshock accelerogram at Oceano yield peak ground accelerations distributed as 28% ?? 4%g. We interpret these realizations as upper bounds for the actual ground motion, because our analysis assumes a linear response, whereas the presence of liquefaction indicates that the ground behaved nonlinearly in Oceano.

  15. ATF CO{sub 2} laser system upgrade to terawatt peak power

    SciTech Connect

    Pogorelsky, I.V.

    1995-05-01

    This document describes the proposed upgrade of the 10-GW peak power 50-ps CO{sub 2} laser presently operational at the ATF to the 1 TW level at a shorter, 3--10 ps, pulse duration. The approach adopted is based on state of the art CO{sub 2} laser technology and an experience gained in the course of the ATF laser design and application for the laser accelerator experiment. The proposed upgrade is an economical way for the ATF to become in a short time among leading users facilities available for next generation ({ge} 100 MeV) laser accelerator studies.

  16. Climatological diurnal variation of negative CG lightning peak current over the continental United States

    NASA Astrophysics Data System (ADS)

    Chronis, T.; Cummins, K.; Said, R.; Koshak, W.; McCaul, E.; Williams, E. R.; Stano, G. T.; Grant, M.

    2015-01-01

    study provides an 11 year climatology of the diurnal variability of the cloud-to-ground (CG) lightning peak current. The local diurnal variation of peak current for negative polarity CG (-CG) flashes exhibits a highly consistent behavior, with increasing magnitudes between the late night to early morning hours and decreasing magnitudes during the afternoon. Over most regions, an inverse relationship exists between the -CG peak current and the corresponding -CG activity, although specific details can depend on region and time of day. Overall, the diurnal variation of the -CG peak current appears to reflect fundamental differences between morning and afternoon storms, but additional studies are required to clearly identify the primary cause(s).

  17. Analysis and Assessment of Peak Lightning Current Probabilities at the NASA Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.; Vaughan, W. W.

    1999-01-01

    This technical memorandum presents a summary by the Electromagnetics and Aerospace Environments Branch at the Marshall Space Flight Center of lightning characteristics and lightning criteria for the protection of aerospace vehicles. Probability estimates are included for certain lightning strikes (peak currents of 200, 100, and 50 kA) applicable to the National Aeronautics and Space Administration Space Shuttle at the Kennedy Space Center, Florida, during rollout, on-pad, and boost/launch phases. Results of an extensive literature search to compile information on this subject are presented in order to answer key questions posed by the Space Shuttle Program Office at the Johnson Space Center concerning peak lightning current probabilities if a vehicle is hit by a lightning cloud-to-ground stroke. Vehicle-triggered lightning probability estimates for the aforementioned peak currents are still being worked. Section 4.5, however, does provide some insight on estimating these same peaks.

  18. Ground water and energy

    SciTech Connect

    Not Available

    1980-11-01

    This national workshop on ground water and energy was conceived by the US Department of Energy's Office of Environmental Assessments. Generally, OEA needed to know what data are available on ground water, what information is still needed, and how DOE can best utilize what has already been learned. The workshop focussed on three areas: (1) ground water supply; (2) conflicts and barriers to ground water use; and (3) alternatives or solutions to the various issues relating to ground water. (ACR)

  19. Ground difference compensating system

    DOEpatents

    Johnson, Kris W.; Akasam, Sivaprasad

    2005-10-25

    A method of ground level compensation includes measuring a voltage of at least one signal with respect to a primary ground potential and measuring, with respect to the primary ground potential, a voltage level associated with a secondary ground potential. A difference between the voltage level associated with the secondary ground potential and an expected value is calculated. The measured voltage of the at least one signal is adjusted by an amount corresponding to the calculated difference.

  20. Efficient accelerator afterburner design based on plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Huang, Chengkun; Blumenfeld, I.; Clayton, C. E.; Decker, F.-J.; Hogan, M. J.; Iverson, R.; Joshi, C.; Katsouleas, T.; Kirby, N.; Lu, W.; Marsh, K. A.; Mori, W. B.; Muggli, P.; Siemann, R.; Walz, D.; Ischebeck, R.; Tzoufras, M.

    2008-11-01

    Recent plasma wakefield acceleration (PWFA) experiment using short (˜100fs), high peak current (>10KA) electron beam as wakefield driver has demonstrated sustained acceleration gradient of ˜50GeV/m over 85 cm. The rapid progress of PWFA experiments has attracted interests regarding the possibility of making an ``afterburner'' for a linear collider. In the ``afterburner'' concept, electron acceleration is achieved by placing a trailing electron beam into the wakefield (either by beam splitting or external injection) to extract energy deposited in the plasma wave wake. Several important aspects of the ``afterburner'' design in the blow-out regime, such as wakefield generation, efficient beam loading and hosing instability have been investigated theoretically. These relevant physics will have great impact on the beam quality of a possible ``afterburner'' design. A multi-stage ``afterburner'' design with 25GeV energy gain in each stage is explored numerically with a 3D quasi-static code QuickPIC. Parameters are suggested for a 0.5 TeV PWFA afterburner with this design and simulation result will be presented.

  1. Quantifying peak discharges for historical floods

    USGS Publications Warehouse

    Cook, J.L.

    1987-01-01

    It is usually advantageous to use information regarding historical floods, if available, to define the flood-frequency relation for a stream. Peak stages can sometimes be determined for outstanding floods that occurred many years ago before systematic gaging of streams began. In the United States, this information is usually not available for more than 100-200 years, but in countries with long cultural histories, such as China, historical flood data are available at some sites as far back as 2,000 years or more. It is important in flood studies to be able to assign a maximum discharge rate and an associated error range to the historical flood. This paper describes the significant characteristics and uncertainties of four commonly used methods for estimating the peak discharge of a flood. These methods are: (1) rating curve (stage-discharge relation) extension; (2) slope conveyance; (3) slope area; and (4) step backwater. Logarithmic extensions of rating curves are based on theoretical plotting techniques that results in straight line extensions provided that channel shape and roughness do not change significantly. The slope-conveyance and slope-area methods are based on the Manning equation, which requires specific data on channel size, shape and roughness, as well as the water-surface slope for one or more cross-sections in a relatively straight reach of channel. The slope-conveyance method is used primarily for shaping and extending rating curves, whereas the slope-area method is used for specific floods. The step-backwater method, also based on the Manning equation, requires more cross-section data than the slope-area ethod, but has a water-surface profile convergence characteristic that negates the need for known or estimated water-surface slope. Uncertainties in calculating peak discharge for historical floods may be quite large. Various investigations have shown that errors in calculating peak discharges by the slope-area method under ideal conditions for

  2. Ground failure in the 2001 Mw 8.4 southern Peru earthquake

    NASA Astrophysics Data System (ADS)

    Rondinel-Oviedo, Efrain Alejandro

    On June 23rd 2001 a moment magnitude (M W) 8.4, earthquake shook the southern portion of Peru. This rare large-magnitude event provided a unique opportunity to develop a suite of high quality case histories and also to test and calibrate existing geotechnical earthquake engineering analysis procedures and models against observations from the earthquake. The work presented in this thesis is focused on three topics pertaining to ground failure (i.e., the permanent deformation of the ground resulting from an earthquake) observed during the event: (1) surface ground damage in small basin geometries, (2) seismic compression, and (3) performance of a concrete faced rockfill dam (CFRD) dam. Surface ground strain damage patterns in small basin geometries has previously been typically studied at the large (i.e., geological) scale, but not at the scale of civil engineering infrastructure. During seismic events basin geometries containing soft material confined by stiffer material trap the seismic waves and generate surface waves that travel on the ground along the soft material. Numerical modeling shows that surface waves are generated at basin edges and travel on the ground creating higher duration, higher response (peak ground acceleration, PGA), higher energy (Arias Intensity) and higher angular distortion, especially in zones close to the edges. The impedance contrast between the stiff material and the soft material, and the dip angle play an important role in basin response. Seismic compression (i.e., the shaking induced densification of unsaturated soil) was observed in many highway embankments in the region of the earthquake. In many instances, this phenomenon was exasperated by soil-structure interaction with adjacent bridge or culvert structures. Numerical modeling conducted as part of this research showed (i) a significantly different response when the structure (culvert) is considered, (ii) impedance contrast plays a role in the system responses, and (iii) low

  3. Study of adaptive correlation filter synthesis guided by the peak and shape of the correlation output

    NASA Astrophysics Data System (ADS)

    Campos Trujillo, Oliver G.; Díaz Blancas, Gerardo

    2014-09-01

    In recent years, many proposals that consider an adaptive perspective had been developed to solve some drawbacks, such as geometric distortions, background noise and target discrimination. The metrics are based only in the correlation peak output for the filter synthesis. In this paper, the correlation shape is studied to implement adaptive correlation filters guided by the peak and shape of the correlation output. Furthermore, the shape of correlation output is studied to improve the search in the filters bank. In addition, parallel algorithms are developed for accelerated the search in the filters bank. Some results are shown, such as time of synthesis, filter performance and comparisons with other adaptive correlation filter proposals.

  4. Structural performance of the DOE's Idaho National Engineering Laboratory during the 1983 Borak Peak earthquake

    SciTech Connect

    Guenzler, R.C.; Gorman, V.W.

    1985-01-01

    The 1983 Borah Peak Earthquake (7.3 Richter magnitude) was the largest earthquake ever experienced by the DOE's Idaho National Engineering Laboratory (INEL). Reactor and plant facilities are generally located about 90 to 110 km (60 miles) from the epicenter. Several reactors were operating normally at the time of the earthquake. Based on detailed inspections, comparisons of measured accelerations with design levels, and instrumental seismograph information, it was concluded that the 1983 Borah Peak Earthquake created no safety problems for INEL reactors or other facilities. 10 refs., 16 figs., 2 tabs.

  5. The direction of acceleration

    NASA Astrophysics Data System (ADS)

    Wilhelm, Thomas; Burde, Jan-Philipp; Lück, Stephan

    2015-11-01

    Acceleration is a physical quantity that is difficult to understand and hence its complexity is often erroneously simplified. Many students think of acceleration as equivalent to velocity, a ˜ v. For others, acceleration is a scalar quantity, which describes the change in speed Δ|v| or Δ|v|/Δt (as opposed to the change in velocity). The main difficulty with the concept of acceleration therefore lies in developing a correct understanding of its direction. The free iOS app AccelVisu supports students in acquiring a correct conception of acceleration by showing acceleration arrows directly at moving objects.

  6. TURBULENT SHEAR ACCELERATION

    SciTech Connect

    Ohira, Yutaka

    2013-04-10

    We consider particle acceleration by large-scale incompressible turbulence with a length scale larger than the particle mean free path. We derive an ensemble-averaged transport equation of energetic charged particles from an extended transport equation that contains the shear acceleration. The ensemble-averaged transport equation describes particle acceleration by incompressible turbulence (turbulent shear acceleration). We find that for Kolmogorov turbulence, the turbulent shear acceleration becomes important on small scales. Moreover, using Monte Carlo simulations, we confirm that the ensemble-averaged transport equation describes the turbulent shear acceleration.

  7. Characteristics of ground motion at permafrost sites along the Qinghai-Tibet railway

    USGS Publications Warehouse

    Wang, L.; Wu, Z.; Sun, Jielun; Liu, Xiuying; Wang, Z.

    2009-01-01

    Based on 14 typical drilling holes distributed in the permafrost areas along the Qinghai-Tibet railway, the distribution of wave velocities of soils in the permafrost regions were determined. Using results of dynamic triaxial tests, the results of dynamic triaxiality test and time histories of ground motion acceleration in this area, characteristics of ground motion response were analyzed for these permafrost sites for time histories of ground accelerations with three exceedance probabilities (63%, 10% and 2%). The influence of ground temperature on the seismic displacement, velocity, acceleration and response spectrum on the surface of permafrost were also studied. ?? 2008 Elsevier Ltd. All rights reserved.

  8. Ground Motion Prediction Equations for data recorded in the immediate vicinity of the San Jacinto fault zone

    NASA Astrophysics Data System (ADS)

    Kurzon, I.; Vernon, F. L.; Ben-Zion, Y.

    2011-12-01

    We present a new set of empirical Ground Motion results for horizontal Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) that include data from the immediate vicinity of the San Jacinto fault zone. The results to date are based on earthquakes in the magnitude range of 1 < M < 5.5 recorded by up to 60 stations at distances ranging from the fault zone itself up to 120km. The data are examined and compared against several models of Ground Motion Prediction Equations (GMPE). The New Generation Attenuation (NGA) project was focused on a magnitude range of M > 5 (e.g., Campbell & Bozorgnia 2006, Boore & Atkinson 2006); therefore, our main comparison is with the ShakeMap system results (Quitoriano 2003 for M < 5.3) and with Cua & Heaton (2008) GMPE accounting for a magnitude range of 2 < M < 8. The data employed so far involves several aftershock sequences on small and known fault segments. These constrains allow for better consideration of the path and site effects, including the path in the near vicinity of the source. Therefore, as opposed to most models (using either the epicentral distance for low magnitude events or the closest surface projection of the fault for stronger events) we consider the hypocentral source-receiver distance as controlling both the geometrical spreading and the inelastic path effects. This approach is not only more physical for M < 5 events, but also reveals the upper crustal heterogeneity (< 20km) in the San Jacinto Fault Zone area. The continuing work will focus on incorporating more data as it becomes available, and using the results to develop updated Ground Motion Prediction Equations. The results will be useful for earthquake engineering and for exploring the crustal heterogeneity around active faults.

  9. Simulations of Ground Motion in Southern California based upon the Spectral-Element Method

    NASA Astrophysics Data System (ADS)

    Tromp, J.; Komatitsch, D.; Liu, Q.

    2003-12-01

    We use the spectral-element method to simulate ground motion generated by recent well-recorded small earthquakes in Southern California. Simulations are performed using a new sedimentary basin model that is constrained by hundreds of petroleum industry well logs and more than twenty thousand kilometers of seismic reflection profiles. The numerical simulations account for 3D variations of seismic wave speeds and density, topography and bathymetry, and attenuation. Simulations for several small recent events demonstrate that the combination of a detailed sedimentary basin model and an accurate numerical technique facilitates the simulation of ground motion at periods of 2 seconds and longer inside the Los Angeles basin and 6 seconds and longer elsewhere. Peak ground displacement, velocity and acceleration maps illustrate that significant amplification occurs in the basin. Centroid-Moment Tensor mechanisms are obtained based upon Pnl and surface waveforms and numerically calculated 3D Frechet derivatives. We use a combination of waveform and waveform-envelope misfit criteria, and facilitate pure double-couple or zero-trace moment-tensor inversions.

  10. Ground Motions Due to Earthquakes on Creeping Faults

    NASA Astrophysics Data System (ADS)

    Harris, R.; Abrahamson, N. A.

    2014-12-01

    We investigate the peak ground motions from the largest well-recorded earthquakes on creeping strike-slip faults in active-tectonic continental regions. Our goal is to evaluate if the strong ground motions from earthquakes on creeping faults are smaller than the strong ground motions from earthquakes on locked faults. Smaller ground motions might be expected from earthquakes on creeping faults if the fault sections that strongly radiate energy are surrounded by patches of fault that predominantly absorb energy. For our study we used the ground motion data available in the PEER NGA-West2 database, and the ground motion prediction equations that were developed from the PEER NGA-West2 dataset. We analyzed data for the eleven largest well-recorded creeping-fault earthquakes, that ranged in magnitude from M5.0-6.5. Our findings are that these earthquakes produced peak ground motions that are statistically indistinguishable from the peak ground motions produced by similar-magnitude earthquakes on locked faults. These findings may be implemented in earthquake hazard estimates for moderate-size earthquakes in creeping-fault regions. Further investigation is necessary to determine if this result will also apply to larger earthquakes on creeping faults. Please also see: Harris, R.A., and N.A. Abrahamson (2014), Strong ground motions generated by earthquakes on creeping faults, Geophysical Research Letters, vol. 41, doi:10.1002/2014GL060228.

  11. Measuring non-local Lagrangian peak bias

    NASA Astrophysics Data System (ADS)

    Biagetti, Matteo; Chan, Kwan Chuen; Desjacques, Vincent; Paranjape, Aseem

    2014-06-01

    We investigate non-local Lagrangian bias contributions involving gradients of the linear density field, for which we have predictions from the excursion set peak formalism. We begin by writing down a bias expansion which includes all the bias terms, including the non-local ones. Having checked that the model furnishes a reasonable fit to the halo mass function, we develop a one-point cross-correlation technique to measure bias factors associated with χ2-distributed quantities. We validate the method with numerical realizations of peaks of Gaussian random fields before we apply it to N-body simulations. We focus on the lowest (quadratic) order non-local contributions -2χ _{10}(k_1\\cdot k_2) and χ _{01}[3(k_1\\cdot k_2)^2-k_1^2 k_2^2], where k_1, k_2 are wave modes. We can reproduce our measurement of χ10 if we allow for an offset between the Lagrangian halo centre-of-mass and the peak position. The sign and magnitude of χ10 is consistent with Lagrangian haloes sitting near linear density maxima. The resulting contribution to the halo bias can safely be ignored for M = 1013 M⊙ h-1, but could become relevant at larger halo masses. For the second non-local bias χ01 however, we measure a much larger magnitude than predicted by our model. We speculate that some of this discrepancy might originate from non-local Lagrangian contributions induced by non-spherical collapse.

  12. Applications of the Strategic Defense Initiative's compact accelerators

    NASA Astrophysics Data System (ADS)

    Montanarelli, Nick; Lynch, Ted

    1991-12-01

    The Strategic Defense Initiative's (SDI) investment in particle accelerator technology for its directed energy weapons program has produced breakthroughs in the size and power of new accelerators. These accelerators, in turn, have produced spinoffs in several areas: the radio frequency quadrupole linear accelerator (RFQ linac) was recently incorporated into the design of a cancer therapy unit at the Loma Linda University Medical Center, an SDI-sponsored compact induction linear accelerator may replace Cobalt-60 radiation and hazardous ethylene-oxide as a method for sterilizing medical products, and other SDIO-funded accelerators may be used to produce the radioactive isotopes oxygen-15, nitrogen-13, carbon-11, and fluorine-18 for positron emission tomography (PET). Other applications of these accelerators include bomb detection, non-destructive inspection, decomposing toxic substances in contaminated ground water, and eliminating nuclear waste.

  13. Applications of the Strategic Defense Initiative's compact accelerators

    NASA Technical Reports Server (NTRS)

    Montanarelli, Nick; Lynch, Ted

    1991-01-01

    The Strategic Defense Initiative's (SDI) investment in particle accelerator technology for its directed energy weapons program has produced breakthroughs in the size and power of new accelerators. These accelerators, in turn, have produced spinoffs in several areas: the radio frequency quadrupole linear accelerator (RFQ linac) was recently incorporated into the design of a cancer therapy unit at the Loma Linda University Medical Center, an SDI-sponsored compact induction linear accelerator may replace Cobalt-60 radiation and hazardous ethylene-oxide as a method for sterilizing medical products, and other SDIO-funded accelerators may be used to produce the radioactive isotopes oxygen-15, nitrogen-13, carbon-11, and fluorine-18 for positron emission tomography (PET). Other applications of these accelerators include bomb detection, non-destructive inspection, decomposing toxic substances in contaminated ground water, and eliminating nuclear waste.

  14. Calculating weighted estimates of peak streamflow statistics

    USGS Publications Warehouse

    Cohn, Timothy A.; Berenbrock, Charles; Kiang, Julie E.; Mason, Jr., Robert R.

    2012-01-01

    According to the Federal guidelines for flood-frequency estimation, the uncertainty of peak streamflow statistics, such as the 1-percent annual exceedance probability (AEP) flow at a streamgage, can be reduced by combining the at-site estimate with the regional regression estimate to obtain a weighted estimate of the flow statistic. The procedure assumes the estimates are independent, which is reasonable in most practical situations. The purpose of this publication is to describe and make available a method for calculating a weighted estimate from the uncertainty or variance of the two independent estimates.

  15. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  16. Improved plasma accelerator

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  17. Technology development for high power induction accelerators

    SciTech Connect

    Birx, D.L.; Reginato, L.L.

    1985-06-11

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability.

  18. PeakVizor: Visual Analytics of Peaks in Video Clickstreams from Massive Open Online Courses.

    PubMed

    Chen, Qing; Chen, Yuanzhe; Liu, Dongyu; Shi, Conglei; Wu, Yingcai; Qu, Huamin

    2016-10-01

    Massive open online courses (MOOCs) aim to facilitate open-access and massive-participation education. These courses have attracted millions of learners recently. At present, most MOOC platforms record the web log data of learner interactions with course videos. Such large amounts of multivariate data pose a new challenge in terms of analyzing online learning behaviors. Previous studies have mainly focused on the aggregate behaviors of learners from a summative view; however, few attempts have been made to conduct a detailed analysis of such behaviors. To determine complex learning patterns in MOOC video interactions, this paper introduces a comprehensive visualization system called PeakVizor. This system enables course instructors and education experts to analyze the "peaks" or the video segments that generate numerous clickstreams. The system features three views at different levels: the overview with glyphs to display valuable statistics regarding the peaks detected; the flow view to present spatio-temporal information regarding the peaks; and the correlation view to show the correlation between different learner groups and the peaks. Case studies and interviews conducted with domain experts have demonstrated the usefulness and effectiveness of PeakVizor, and new findings about learning behaviors in MOOC platforms have been reported. PMID:26661473

  19. Rail accelerators for space transportation: An experimental investigation

    NASA Technical Reports Server (NTRS)

    Zana, L. M.; Kerslake, W. R.; Sturman, J. L.

    1986-01-01

    An experimental program was conducted at the Lewis Research Center with the objective of investigating the technical feasibility of rail accelerators for propulsion applications. Single-stage, plasma driven rail accelerators of small (4 by 6 mm) and medium (12.5 by 12.5 mm) bores were tested at peak accelerating currents of 50 to 450 kA. Streak-camera photography was used to provide a qualitative description of plasma armature acceleration. The effects of plasma blowby and varying bore pressure on the behavior of plasma armatures were studied.

  20. Documented and potential extreme peak discharges and relation between potential extreme peak discharges and probable maximum flood peak discharges in Texas

    USGS Publications Warehouse

    Asquith, W.H.; Slade, R.M., Jr.

    1995-01-01

    The U.S. Geological Survey, in cooperation with the Texas Department of Transportation, conducted a study of extreme flood potential for Texas. Potential extreme peak discharges, derived from the relation between documented extreme peak discharges and their contributing drainage areas, can provide valuable information concerning the maximum expected peak discharge that could occur at a stream site. Documented extreme peak discharges and associated data were aggregated for 832 sites with and without streamflow-gaging stations in natural basins in Texas. A potential extreme peak discharge curve was developed for each of 11 hydrologic regions in Texas and for the State as a whole, based on documented extreme peak discharges and associated contributing drainage areas. The curve envelops, for a large range of drainage areas, the largest documented extreme peak discharges. Potential extreme peak discharges estimated from the curves were compared to probable maximum flood peak discharges estimated from various simulation models.

  1. Acceleration gradient of a plasma wakefield accelerator

    SciTech Connect

    Uhm, Han S.

    2008-02-25

    The phase velocity of the wakefield waves is identical to the electron beam velocity. A theoretical analysis indicates that the acceleration gradient of the wakefield accelerator normalized by the wave breaking amplitude is K{sub 0}({xi})/K{sub 1}({xi}), where K{sub 0}({xi}) and K{sub 1}({xi}) are the modified Bessel functions of the second kind of order zero and one, respectively and {xi} is the beam parameter representing the beam intensity. It is also shown that the beam density must be considerably higher than the diffuse plasma density for the large radial velocity of plasma electrons that are required for a high acceleration gradient.

  2. A relationship between peak temperature drop and velocity differential in a microburst

    NASA Technical Reports Server (NTRS)

    Proctor, Fred H.

    1989-01-01

    Results from numerical microburst simulations using the Terminal Area Simulation System (Proctor, 1987) are used to develop a relationship between wind velocity differential and peak temperature drop. The numerical model and the relationships derived from the model are described. The relationship between peak temperature drop and differential wind velocity is shown to be valid during microburst development, for all precipitation shaft intensities and diameters. It is found that the relationship is not valid for low-reflectivity microburst events or in the presence of ground-based stable layers. The use of the relationship in IR wind shear detection systems is considered.

  3. Far field acceleration

    SciTech Connect

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.

  4. Angular Acceleration Without Torque?

    NASA Astrophysics Data System (ADS)

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.2

  5. Sustained linear acceleration

    NASA Technical Reports Server (NTRS)

    Fraser, T. M.

    1973-01-01

    The subjective effects of sustained acceleration are discussed, including positive, negative, forward, backward, and lateral acceleration effects. Physiological effects, such as retinal and visual response, unconsciousness and cerebral function, pulmonary response, and renal output, are studied. Human tolerance and performance under sustained acceleration are ascertained.

  6. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  7. Acceleration: It's Elementary

    ERIC Educational Resources Information Center

    Willis, Mariam

    2012-01-01

    Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

  8. Outreach Plans for Storm Peak Laboratory

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; McCubbin, I. B.

    2006-12-01

    The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located on the west summit of Mt. Werner in the Park Range near Steamboat Springs, Colorado at an elevation 10,500 ft. SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. SPL includes an office-type laboratory room for computer and instrumentation setup with outside air ports and cable access to the roof deck, a full kitchen and two bunk rooms with sleeping space for nine persons. We plan to create a unique summer undergraduate education experiences for students of diversity at Storm Peak Laboratory. As stressed by the College Pathways to Science Education Standards [Siebert and McIntosh, 2001], to support changes in K-12 science education transformations must first be made at the college level, including inquiry-oriented opportunities to engage in meaningful research. These workshops will be designed to allow students to experience the excitement of science, increasing their likelihood of pursing careers within the fields of scientific education or research.

  9. Low peak-power laser ultrasonics

    NASA Astrophysics Data System (ADS)

    Pierce, S. G.; Cleary, A.; Veres, I. A.; Culshaw, B.; Thursby, G.; McKee, C.; Swift, C.; Armstrong, I.

    2011-09-01

    Techniques for the successful excitation of guided ultrasonic waves using a low peak-power laser ultrasonic source are discussed and compared with more conventional Q-switched laser sources. The paper considers acoustic propagation in thin plates, in which the frequencies used, typically only the fundamental guided wave modes, are considered. Aspects of excitation and detection geometry are considered along with the physical mechanisms of photo-acoustic generation and the practical issues surrounding available source wavelengths and power outputs. Understanding of the effects of these constraints is critical for the successful application of the technique. Continuous wave excitation and fully arbitrary modulation schemes are compared, and a technique to control the bandwidth of Golay code modulation is introduced. It is shown that earlier work by the authors was capable of guided wave detection at peak-power densities of 104 W cm- 2. Later work has focussed on the use of erbium-doped fibre amplifiers combined with Golay code modulation to improve the recovered signal-to-noise ratio. Two key applications of the techniques are considered: material properties measurements (using inversion of dispersion curve data) and acoustic emission system calibration.

  10. Microwave peak absorption frequency of liquid

    NASA Astrophysics Data System (ADS)

    Han, Guangze; Chen, Mingdong

    2008-09-01

    Microwave-assisted extraction is a new effective method which has practical applications in many fields. Microwave heating is one of its physical mechanisms, and it also has the characteristic of selectivity. When the applied microwave frequency equals a certain absorption frequency of the material (or specific component), the material will intensively absorb microwave energy. This is also known as resonant absorption, and the frequency is called the peak absorption frequency which depends on the physical structure of the material. In this work, dynamic hydrogen bond energy was included in molecular activation energy; with the liquid cell model, the expression of interaction energy between dipolar molecules was derived. The rotational relaxation time was gotten from the Eyring viscosity formula. Then based on the relationship between dielectric dissipation coefficient and relaxation time, the expression of microwave peak absorption frequency as a function of the material physical structure, rotational inertia and electrical dipole moment of molecules was established. These theoretical formulas were applied to water and benzene, and the calculated results agree fairly well with the experimental data. This work can not only deepen the study of the interaction between microwave and material, but also provide a possible guide for the experiment of microwave-assisted extraction.

  11. Linking ground motion measurements and macroseismic observations in France: a case study based on accelerometric and macroseismic databases

    NASA Astrophysics Data System (ADS)

    Lesueur, Chloé; Cara, Michel; Scotti, Oona; Schlupp, Antoine; Sira, Christophe

    2013-04-01

    Comparison between accelerometric and macroseismic observations is made for three M w = 4.5 earthquakes, which occurred in north-eastern France and south-western Germany in 2003 and 2004. Scalar and spectral instrumental parameters are processed from the accelerometric data recorded by nine accelerometric stations located between 29 and 180 km from the epicentres. Macroseismic data are based on French Internet reports. In addition to the single questionnaire intensity, analysis of the internal correlation between the encoded answers highlights four predominant fields of questions bearing different physical meanings: (1) "vibratory motions of small objects", (2) "displacement and fall of objects", (3) "acoustic noise" and (4) "personal feelings". Best correlations between macroseismic and instrumental observations are obtained when the macroseismic parameters are averaged over 10-km-radius circles around each station. Macroseismic intensities predicted by published peak ground velocity (PGV)-intensity relationships agree with our observed intensities, contrary to those based on peak ground acceleration (PGA). Correlation between the macroseismic and instrumental data for intensities between II and V (EMS-98) is better for PGV than for PGA. Correlation with the response spectra exhibits clear frequency dependence for all macroseismic parameters. Horizontal and vertical components are significantly correlated with the macroseismic parameters between 1 and 10 Hz, a range corresponding to both natural frequencies of most buildings and high energy content in the seismic ground motion. Between 10 and 25 Hz, a clear lack of correlation between macroseismic and instrumental observations exists. It could be due to a combination of the decrease in the energy signal above 10 Hz, a high level of anthropogenic noise and an increase in variability in soil conditions. Above 25 Hz, the correlation coefficients between the acceleration response spectra and the macroseismic

  12. A preliminary assessment of earthquake ground shaking hazard at Yucca Mountain, Nevada and implications to the Las Vegas region

    SciTech Connect

    Wong, I.G.; Green, R.K.; Sun, J.I.; Pezzopane, S.K.; Abrahamson, N.A.; Quittmeyer, R.C.

    1996-12-31

    As part of early design studies for the potential Yucca Mountain nuclear waste repository, the authors have performed a preliminary probabilistic seismic hazard analysis of ground shaking. A total of 88 Quaternary faults within 100 km of the site were considered in the hazard analysis. They were characterized in terms of their probability o being seismogenic, and their geometry, maximum earthquake magnitude, recurrence model, and slip rate. Individual faults were characterized by maximum earthquakes that ranged from moment magnitude (M{sub w}) 5.1 to 7.6. Fault slip rates ranged from a very low 0.00001 mm/yr to as much as 4 mm/yr. An areal source zone representing background earthquakes up to M{sub w} 6 1/4 = 1/4 was also included in the analysis. Recurrence for these background events was based on the 1904--1994 historical record, which contains events up to M{sub w} 5.6. Based on this analysis, the peak horizontal rock accelerations are 0.16, 0.21, 0.28, and 0.50 g for return periods of 500, 1,000, 2,000, and 10,000 years, respectively. In general, the dominant contributor to the ground shaking hazard at Yucca Mountain are background earthquakes because of the low slip rates of the Basin and Range faults. A significant effect on the probabilistic ground motions is due to the inclusion of a new attenuation relation developed specifically for earthquakes in extensional tectonic regimes. This relation gives significantly lower peak accelerations than five other predominantly California-based relations used in the analysis, possibly due to the lower stress drops of extensional earthquakes compared to California events. Because Las Vegas is located within the same tectonic regime as Yucca Mountain, the seismic sources and path and site factors affecting the seismic hazard at Yucca Mountain also have implications to Las Vegas. These implications are discussed in this paper.

  13. Ground motion simulation for the 23 August 2011, Mineral, Virginia earthquake using physics-based and stochastic broadband methods

    USGS Publications Warehouse

    Sun, Xiaodan; Hartzell, Stephen; Rezaeian, Sanaz

    2015-01-01

    Three broadband simulation methods are used to generate synthetic ground motions for the 2011 Mineral, Virginia, earthquake and compare with observed motions. The methods include a physics‐based model by Hartzell et al. (1999, 2005), a stochastic source‐based model by Boore (2009), and a stochastic site‐based model by Rezaeian and Der Kiureghian (2010, 2012). The ground‐motion dataset consists of 40 stations within 600 km of the epicenter. Several metrics are used to validate the simulations: (1) overall bias of response spectra and Fourier spectra (from 0.1 to 10 Hz); (2) spatial distribution of residuals for GMRotI50 peak ground acceleration (PGA), peak ground velocity, and pseudospectral acceleration (PSA) at various periods; (3) comparison with ground‐motion prediction equations (GMPEs) for the eastern United States. Our results show that (1) the physics‐based model provides satisfactory overall bias from 0.1 to 10 Hz and produces more realistic synthetic waveforms; (2) the stochastic site‐based model also yields more realistic synthetic waveforms and performs superiorly for frequencies greater than about 1 Hz; (3) the stochastic source‐based model has larger bias at lower frequencies (<0.5  Hz) and cannot reproduce the varying frequency content in the time domain. The spatial distribution of GMRotI50 residuals shows that there is no obvious pattern with distance in the simulation bias, but there is some azimuthal variability. The comparison between synthetics and GMPEs shows similar fall‐off with distance for all three models, comparable PGA and PSA amplitudes for the physics‐based and stochastic site‐based models, and systematic lower amplitudes for the stochastic source‐based model at lower frequencies (<0.5  Hz).

  14. A reliable simultaneous representation of seismic hazard and of ground shaking recurrence

    NASA Astrophysics Data System (ADS)

    Peresan, A.; Panza, G. F.; Magrin, A.; Vaccari, F.

    2015-12-01

    Different earthquake hazard maps may be appropriate for different purposes - such as emergency management, insurance and engineering design. Accounting for the lower occurrence rate of larger sporadic earthquakes may allow to formulate cost-effective policies in some specific applications, provided that statistically sound recurrence estimates are used, which is not typically the case of PSHA (Probabilistic Seismic Hazard Assessment). We illustrate the procedure to associate the expected ground motions from Neo-deterministic Seismic Hazard Assessment (NDSHA) to an estimate of their recurrence. Neo-deterministic refers to a scenario-based approach, which allows for the construction of a broad range of earthquake scenarios via full waveforms modeling. From the synthetic seismograms the estimates of peak ground acceleration, velocity and displacement, or any other parameter relevant to seismic engineering, can be extracted. NDSHA, in its standard form, defines the hazard computed from a wide set of scenario earthquakes (including the largest deterministically or historically defined credible earthquake, MCE) and it does not supply the frequency of occurrence of the expected ground shaking. A recent enhanced variant of NDSHA that reliably accounts for recurrence has been developed and it is applied to the Italian territory. The characterization of the frequency-magnitude relation can be performed by any statistically sound method supported by data (e.g. multi-scale seismicity model), so that a recurrence estimate is associated to each of the pertinent sources. In this way a standard NDSHA map of ground shaking is obtained simultaneously with the map of the corresponding recurrences. The introduction of recurrence estimates in NDSHA naturally allows for the generation of ground shaking maps at specified return periods. This permits a straightforward comparison between NDSHA and PSHA maps.

  15. Macroseismic Intensity and Instrumental Ground Motion Parameter Correlations for Central Mexico

    NASA Astrophysics Data System (ADS)

    Sandoval Gómez, H.; Ramirez Guzman, L.; Espindola, V.

    2012-12-01

    We present instrumental intensity prediction equations for earthquakes in Central Mexico based on the correlation of observed Instrumental Ground-Motion Parameters (IGMP) and Modified Mercalli Intensity (MMI) scale reports. The goal of this study is to provide a model that can be used by the near real-time earthquake response system operated by the Institutes of Engineering and Geophysics at the National Autonomous University of Mexico (UNAM), which delivers estimates of key information associated with the societal impact due to earthquakes not available in the immediate aftermath of the event. Correlations of MMI and IGMP have been derived in other countries with different tectonic settings and built environments, but this is the first study devoted to the development of equations for the central region of Mexico. The IGMP are obtained from records of several stations for earthquakes with Mw 5.0-8.0 from the seismic networks operated by UNAM and other institutions in Mexico. The MMI observations were primarily obtained from the Did You Feel It (DYFI) report service of the U.S. Geological Survey and re-interpreted MMI reports from UNAM earthquake bulletin archives. For each instrumental observation we assigned a mean MMI intensity based on the proximity of the site where reported value are available, constrained by geological conditions and a visual inspection to guarantee that the intensity would be within one unit of the assigned value; following the procedure by Atkinson and Kaka (2006). We derived correlations for peak ground velocity (pgv) and acceleration, and three spectral acceleration periods (T=1, 2 and 3 s). In addition, we analyzed the Mw and distance dependence. We concluded that pgv and the spectral accelerations are the most useful IGMP predictors for MMI in the region of interest and the correlations differ significantly from those obtained in regions with other tectonic settings and infrastructure vulnerabilities (e.g. Wald et al, 1999; Atkinson

  16. GROUND WATER SAMPLING ISSUES

    EPA Science Inventory

    Obtaining representative ground water samples is important for site assessment and
    remedial performance monitoring objectives. Issues which must be considered prior to initiating a ground-water monitoring program include defining monitoring goals and objectives, sampling point...

  17. Ground Water Remediation Technologies

    EPA Science Inventory

    The USEPA's Ground Water and Ecosystems Restoration Division (GWERD) conducts research and provides technical assistance to support the development of strategies and technologies to protect and restore ground water, surface water, and ecosystems impacted by man-made and natural...

  18. Ground Motion Prediction Equations Empowered by Stress Drop Measurement

    NASA Astrophysics Data System (ADS)

    Miyake, H.; Oth, A.

    2015-12-01

    Significant variation of stress drop is a crucial issue for ground motion prediction equations and probabilistic seismic hazard assessment, since only a few ground motion prediction equations take into account stress drop. In addition to average and sigma studies of stress drop and ground motion prediction equations (e.g., Cotton et al., 2013; Baltay and Hanks, 2014), we explore 1-to-1 relationship for each earthquake between stress drop and between-event residual of a ground motion prediction equation. We used the stress drop dataset of Oth (2013) for Japanese crustal earthquakes ranging 0.1 to 100 MPa and K-NET/KiK-net ground motion dataset against for several ground motion prediction equations with volcanic front treatment. Between-event residuals for ground accelerations and velocities are generally coincident with stress drop, as investigated by seismic intensity measures of Oth et al. (2015). Moreover, we found faster attenuation of ground acceleration and velocities for large stress drop events for the similar fault distance range and focal depth. It may suggest an alternative parameterization of stress drop to control attenuation distance rate for ground motion prediction equations. We also investigate 1-to-1 relationship and sigma for regional/national-scale stress drop variation and current national-scale ground motion equations.

  19. Compact Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2004-01-01

    A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

  20. Ground water: a review.

    USGS Publications Warehouse

    Bredehoeft, J.D.

    1983-01-01

    There is growing documentation that a significant portion of the Nation's fresh ground water in the densely populated areas of the USA is contaminated. Because of the slow rates of ground-water movement, ground water once contaminated will remain so for decades, often longer. Cleanup of contaminated ground water is almost always expensive and often technically unfeasible; the expense is often prohibitive. -from Author

  1. SSI effects on ground motion at Lotung LSST Site

    SciTech Connect

    Borja, R.I.; Montans, F.J.; Lin, C.H.; Chao, H.Y.

    1999-09-01

    A 3D finite-element model is developed to study soil-structure interaction (SSI) effects at a Large-Scale Seismic Test (LSST) site in Lotung, Taiwan, during the earthquake of May 20, 1986. Analyses are carried out by direct method incorporating a 1/4-scale nuclear plant containment structure. The containment structure is modeled as a linearly elastic material, while the subsoil is modeled as an elastoplastic continuum material that deforms plastically according to a bounding surface plasticity theory with a vanishing elastic region. Eigenvalue analyses are performed to see how the presence of the structure affects the fundamental frequencies and modes of vibration of the system in the limit of elastic response. SSI effects are shown to be partly responsible for the reduced peak north-south ground surface acceleration recorded by a downhole array near the containment structure. Eigenvalue studies suggest that the local effect of the containment structure is to generate rocking and torsional vibration modes, in addition to the usual lateral and vertical modes. However, results of time domain studies indicate that the former modes (rocking and torsional) were not triggered by the 1986 earthquake.

  2. Investigation of the relationship between ground and engineering bedrock at northern part of the Gulf of İzmir by borehole data supported geophysical works

    NASA Astrophysics Data System (ADS)

    Akgün, Mustafa; Gönenç, Tolga; Pamukçu, Oya; Özyalin, Şenol

    2014-04-01

    Loss of life and property that may occur as a result of a possible earthquake can be reduced by earthquake resistant building designs. In order to investigate possible ground motion amplification in earthquake resistant building design, relationship between the ground and engineering bedrock must be ensured. In order to provide this relation, structure, basic characteristics, and thickness of the ground are investigated. In this context, calculating ground transfer function, obtaining horizontal earthquake acceleration changes, calculating Vs values and defining the engineering bedrock are necessary. In this study, Menemen plain, the nothern part of Izmir metropolitan located in active earthquake zone and its immediate vicinity have been examined to define the structure, ground, engineering and bedrock relation. In this context, Menemen plain has been investigated by geophysical methods, which are supported with borehole data (microtremor, MASW - multichannel analysis of surface waves, microgravity measurements, and vertical electrical sounding-VES). Microtremor method was conducted at 377 points in average in the investigation area to define fundamental period and empirical transfer function; after that in order to create basin model and to define the shallow subsurface geometry, microgravity measurements were carried out by using Scintrex CG-5. Also, MASW measurements were carried out in approximately 277 profiles and Schlumberger VES measurements were conducted at approximately 7 points in the investigation area. The existence of a linear relation between H/V peak period values obtained by microtremor measurements and ground thickness in the investigation area is also supported by geothermal drilling logs (depth of 600 m) with microgravity survey. Also, in some parts of the investigation area, it was observed that high S velocity ( Vs) values affected H/V peak period values in sections of the ground close to the surface and there was an inversely correlated

  3. Mineral resources of the Redcloud Peak and Handies Peak Wilderness Study Areas, Hinsdale County, Colorado

    SciTech Connect

    Sanford, R.F.; Grauch, R.I.; Hon, K.; Bove, D.J.; Grauch, V.J.S.; Korzeb, S.L.

    1987-01-01

    The Redcloud Peak and Handies Peak Wilderness Study Areas are located 2-12 mi southwest of Lake City, CO. Much of the study areas has high mineral resource potential for precious and base metals in various ore deposit types. The rest of the study areas has moderate potential for these commodities. Two areas in the Redcloud Peak study area have moderate potential for molybdenum and copper in quartz monzonite-associated porphyry deposits. Part of the Handies Peak study area has moderate potential for molybdenum in granite-related porphyry deposits. The southwestern part of the Redcloud Peak study area has high potential for uranium in vein-type deposits. Moderate potential for this commodity extends over other parts of both study areas. The mineral resource potential for gold and silver (in clastic-sediment-hosted disseminated-type epithermal deposits) is low in those parts of both study areas underlain by the Henson Member of the Silverton Volcanics. The mineral and energy resource potential for aluminum (in alunite deposits), uranium (in disseminated deposits), and geothermal sources is low throughout both study areas. Based on currently available data, there is no energy resource potential for coal, oil, and natural gas. The study areas have no identified resources.

  4. High brightness electron accelerator

    DOEpatents

    Sheffield, Richard L.; Carlsten, Bruce E.; Young, Lloyd M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  5. Fiber Accelerating Structures

    SciTech Connect

    Hammond, Andrew P.; /Reed Coll. /SLAC

    2010-08-25

    One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.

  6. Twin Peaks in 360-degree panorama

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The prominent hills dubbed 'Twin Peaks' approximately 1-2 kilometers away were imaged by the Imager for Mars Pathfinder (IMP) as part of a 360-degree color panorama, taken over sols 8, 9 and 10. A lander petal and deflated airbag are at the bottom of the image.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  7. NMR solvent peak suppression by nonlinear excitation

    NASA Astrophysics Data System (ADS)

    Levitt, Malcolm H.

    1988-03-01

    Most existing NMR solvent peak suppression sequences provide a satisfactory dependence of the intensity of excited signals on frequency but poor phase characteristics. In practice this leads to spectral distortions which generally become more severe as the frequency selectivity of the sequence is increased. However, it is shown that by working well outside the linear response regime, excitation schemes which combine high frequency selectivity with good phase properties may be devised. Sequences of six rectangular radio-frequency pulses were discovered using a combination of coherent averaging theory to treat the near-resonant behavior and numerical simulation further from resonance. Extensive use of symmetry greatly simplifies both the coherent averaging calculations and the numerical simulations. The new pulse sequences have been given the acronym NERO (nonlinear excitation rejecting on-resonance). Experimental spectra of an enzyme in dilute aqueous solution are shown.

  8. BUFFALO PEAKS WILDERNESS STUDY AREA, COLORADO.

    USGS Publications Warehouse

    Hedlund, D.C.; Wood, R.H.

    1984-01-01

    Field investigations were conducted to evaluate the mineral-resource potential of the Buffalo Peaks Wilderness Study Area, Colorado. On the basis of this study there is a probable mineral-resource potential for silver vein and bedding replacement deposits along the Weston Pass fault zone, for hydrothermal vein-type uranium deposits in the vicinity of the Parkdale iron pit, and for gold vein deposits in the parts of the Granite and Four Mile districts that are within the wilderness study area. A probable barite resource potential occurs at Rough and Tumbling Creek and near Spring Creek on the east side of the study area. There is little promise for the occurrence of energy resources.

  9. The cosmic-ray ground-level enhancement of 1989 September 29

    SciTech Connect

    Moraal, H.; Caballero-Lopez, R. A.

    2014-08-01

    The ground-level enhancement (GLE) of 1989 September 29 is one of the largest of 71 solar energetic particle events observed by neutron monitors on Earth. It was smaller than the record-breaking GLE 5 of 1956 February 23, but by some measures it was larger than GLE 69 of 2005 January 20. It is also the most extensively studied of the 71 GLEs, and it was observed by more than 50 ground-based detectors in the worldwide network. This paper contains another study of the event, with the main difference from previous studies that all the existing observations are employed, instead of the usual selection of stations. An effort is made to represent all the information graphically. This reveals new insight in the event, mainly about its time profile. The main conclusion is that the event is the best example available of a 'classical' GLE that has a gradual increase toward peak intensity and does not contain two or more distinct peaks as inferred previously. It does, however, suggest that there were two acceleration or release mechanisms: a prompt, rapid one and a delayed, slower one. This conclusion is based on a detailed comparison with GLE 69 of 2005 January 20, which is the best-known example of a double-peaked event with a 'prompt' component. It is also found that the rigidity spectrum was probably softer than derived in several previous studies, and that the decay phase of the event reveals that the cosmic-ray diffusion coefficient in the neutron monitor range is proportional to rigidity.

  10. Sample distribution in peak mode isotachophoresis

    SciTech Connect

    Rubin, Shimon; Schwartz, Ortal; Bercovici, Moran

    2014-01-15

    We present an analytical study of peak mode isotachophoresis (ITP), and provide closed form solutions for sample distribution and electric field, as well as for leading-, trailing-, and counter-ion concentration profiles. Importantly, the solution we present is valid not only for the case of fully ionized species, but also for systems of weak electrolytes which better represent real buffer systems and for multivalent analytes such as proteins and DNA. The model reveals two major scales which govern the electric field and buffer distributions, and an additional length scale governing analyte distribution. Using well-controlled experiments, and numerical simulations, we verify and validate the model and highlight its key merits as well as its limitations. We demonstrate the use of the model for determining the peak concentration of focused sample based on known buffer and analyte properties, and show it differs significantly from commonly used approximations based on the interface width alone. We further apply our model for studying reactions between multiple species having different effective mobilities yet co-focused at a single ITP interface. We find a closed form expression for an effective-on rate which depends on reactants distributions, and derive the conditions for optimizing such reactions. Interestingly, the model reveals that maximum reaction rate is not necessarily obtained when the concentration profiles of the reacting species perfectly overlap. In addition to the exact solutions, we derive throughout several closed form engineering approximations which are based on elementary functions and are simple to implement, yet maintain the interplay between the important scales. Both the exact and approximate solutions provide insight into sample focusing and can be used to design and optimize ITP-based assays.

  11. Predictions of high-frequency ground-motion in Taiwan based on weak motion data

    NASA Astrophysics Data System (ADS)

    D'Amico, Sebastiano; Akinci, Aybige; Malagnini, Luca

    2012-04-01

    Following a recent paper we use weak-motion waveforms to calibrate a model for the prediction of earthquake-induced ground-motion in Taiwan, in the 0.25-5.0 Hz frequency range, valid up to Mw 7.6. The excitation/attenuation model is given in terms of frequency-dependent seismic wave attenuation, Qs(f), geometrical spreading, g(r), a magnitude-dependent stress parameters Δσ for the excitation terms, and a site term for each seismic station used in the study. A set of weak-motion data was gathered from about 170 aftershocks of the Chi-Chi earthquake, Mw 7.6, of 1999 September 20, (17:47 UTC), recorded by 10 broad-band seismic stations. The moment magnitudes of the registered aftershocks ranged from Mw 3.0 to 6.5, and the hypocentral distances from a few kilometres to about 250 km. A frequency-dependent crustal quality factor, Q(f) = 350f0.32, was obtained, to be coupled with the geometrical spreading function Earthquake-related excitation spectra were calibrated over our empirical results by using a magnitude-dependent Brune model with a stress drop value of Δσ= 8.0 ± 1.0 MPa for the largest event of Mw 6.5 in our data set and with a near surface attenuation parameter of κ= 0.05 s. Results on region-specific crustal attenuation and source scaling were used to generate stochastic simulations both for point-source and extended-fault ruptures through the computer codes: Stochastic Model SIMulation, SMSIM and Extended-Fault Model Simulation, EXSIM. The absolute peak ground accelerations (PGA), peak ground velocities (PGV) and 5 per cent-damped Spectral Accelerations (SA) at three different frequencies, 0.33 Hz, 1.0 Hz and 3.0 Hz for several magnitudes and distance ranges were predicted at large magnitudes, well beyond magnitude Mw 6.5, the upper limit for the events of our

  12. Acceleration in astrophysics

    SciTech Connect

    Colgate, S.A.

    1993-12-31

    The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

  13. A torque controlled high speed flywheel energy storage system for peak power transfer in electric vehicles

    SciTech Connect

    Schaible, U.; Szabados, B.

    1994-12-31

    This paper provides a design outline and implementation procedure for a flywheel energy storage system using a high speed interior permanent magnet synchronous machine, torque-controlled through the use of a vector control algorithm. The proposed flywheel energy storage system can be used to meet the peak energy requirements of an electric vehicle during both acceleration and regenerative braking. By supplying the peak energy requirements from a secondary source, the life cycle of the electric vehicle`s batteries may be extended considerably. A torque control algorithm is presented and preliminary implementation through a commercially available microcontroller is described. Preliminary testing of the proposed system has been very promising and has proven that bidirectional peak power transfer can be rapidly accomplished. 4 refs.

  14. Ground motions at the outermost limits of seismically triggered landslides

    USGS Publications Warehouse

    Jibson, Randall W.; Harp, Edwin L.

    2016-01-01

    Over the last few decades, we and our colleagues have conducted field investigations in which we mapped the outermost limits of triggered landslides in four earthquakes: 1987 Whittier Narrows, California (M 5.9), 1987 Superstition Hills, California (M 6.5), 1994 Northridge, California (M 6.7), and 2011 Mineral, Virginia (M 5.8). In an additional two earthquakes, 1976 Guatemala (M 7.5) and 1983 Coalinga, California (M 6.5), we determined limits using high‐resolution aerial‐photographic interpretation in conjunction with more limited ground investigation. Limits in these earthquakes were defined by the locations of the very smallest failures (<1  m3) from the most susceptible slopes that can be identified positively as having been triggered by earthquake shaking. Because we and our colleagues conducted all of these investigations, consistent methodology and criteria were used in determining limits. In the six earthquakes examined, we correlated the outermost landslide limits with peak ground accelerations (PGAs) from ShakeMap models of each earthquake. For the four earthquakes studied by field investigation, the minimum PGA values associated with farthest landslide limits ranged from 0.02g to 0.08g. The range for the two earthquakes investigated using aerial‐photographic interpretations was 0.05–0.11g. Although PGA values at landslide limits depend on several factors, including material strength, topographic amplification, and hydrologic conditions, these values provide an empirically useful lower limiting range of PGA needed to trigger the smallest failures on very susceptible slopes. In a well‐recorded earthquake, this PGA range can be used to identify an outer boundary within which we might expect to find landsliding; in earthquakes that are not well recorded, mapping the outermost landslide limits provides a useful clue about ground‐motion levels at the mapped limits.

  15. Peak holding circuit for extremely narrow pulses

    NASA Technical Reports Server (NTRS)

    Oneill, R. W. (Inventor)

    1975-01-01

    An improved pulse stretching circuit comprising: a high speed wide-band amplifier connected in a fast charge integrator configuration; a holding circuit including a capacitor connected in parallel with a discharging network which employs a resistor and an FET; and an output buffer amplifier. Input pulses of very short duration are applied to the integrator charging the capacitor to a value proportional to the input pulse amplitude. After a predetermined period of time, conventional circuitry generates a dump pulse which is applied to the gate of the FET making a low resistance path to ground which discharges the capacitor. When the dump pulse terminates, the circuit is ready to accept another pulse to be stretched. The very short input pulses are thus stretched in width so that they may be analyzed by conventional pulse height analyzers.

  16. Strong ground motions generated by earthquakes on creeping faults

    USGS Publications Warehouse

    Harris, Ruth A.; Abrahamson, Norman A.

    2014-01-01

    A tenet of earthquake science is that faults are locked in position until they abruptly slip during the sudden strain-relieving events that are earthquakes. Whereas it is expected that locked faults when they finally do slip will produce noticeable ground shaking, what is uncertain is how the ground shakes during earthquakes on creeping faults. Creeping faults are rare throughout much of the Earth's continental crust, but there is a group of them in the San Andreas fault system. Here we evaluate the strongest ground motions from the largest well-recorded earthquakes on creeping faults. We find that the peak ground motions generated by the creeping fault earthquakes are similar to the peak ground motions generated by earthquakes on locked faults. Our findings imply that buildings near creeping faults need to be designed to withstand the same level of shaking as those constructed near locked faults.

  17. DOUBLE-PEAKED NARROW-LINE ACTIVE GALACTIC NUCLEI. II. THE CASE OF EQUAL PEAKS

    SciTech Connect

    Smith, K. L.; Shields, G. A.; Salviander, S.; Stevens, A. C.; Rosario, D. J. E-mail: shields@astro.as.utexas.edu E-mail: acs0196@mail.utexas.edu

    2012-06-10

    Active galactic nuclei (AGNs) with double-peaked narrow lines (DPAGNs) may be caused by kiloparsec-scale binary AGNs, bipolar outflows, or rotating gaseous disks. We examine the class of DPAGNs in which the two narrow-line components have closely similar intensity as being especially likely to involve disks or jets. Two spectroscopic indicators support this likelihood. For DPAGNs from Smith et al., the 'equal-peaked' objects (EPAGNs) have [Ne V]/[O III]ratios lower than for a control sample of non-double-peaked AGNs. This is unexpected for a pair of normal AGNs in a galactic merger, but may be consistent with [O III] emission from a rotating ring with relatively little gas at small radii. Also, [O III]/H{beta} ratios of the redshifted and blueshifted systems in the EPAGN are more similar to each other than in a control sample, suggestive of a single ionizing source and inconsistent with the binary interpretation.

  18. An analysis of Super typhoon Rammasun's(2014) peak intensity

    NASA Astrophysics Data System (ADS)

    Cai, Qinbo; Xu, Yinglong

    2016-04-01

    Super typhoon Rammasun (2014) made landfall over Hainan Island, China, at 0730UTC 18 July 2014. Due to the damage of the anemometers, the Automatic Weather Stations (AWS) and the bouy which by Rammasun passed, failed to obtain its peak wind. Lack of the direct evident, in real-time monitoring, its peak intensities were given by 110kts (.i.e. 60m/s)/910hPa,135kts/922hPa , and 90kts/935hPa based on Dvorak technique , which were made by China Meteorological Administration (CMA),Joint Typhoon Warning Center(JTWC), and Japan Meteorological Agency (JMA) respectively. However, a minimum pressure of 881.2hPa recorded by a barometer which located at Qixhou island (19.982︒N,111.269︒E) while Rammasun approaching, indicates that its intensity was under estimated. By using observation data such as AWS, satellite, Doppler radar and wind tower near the ground, this study performs a detail evaluation to obtain its actual intensity. At 0521UTC, Qizhou Island station recorded 881.2hPa of the minimum station pressure and 899.2hPa of minimum sea level pressure (MSLP) while the anemometer had been destroyed. These are the lowest records in Chinese history and also are ones of the global lowest pressures obtained directly by barometer. It is evident that Rammasun's eyewall did not pass across Qizhou Island directly, so the actual MSLP should be lower than 899.2hPa. By applying wind-pressure relationship, it is reckoned that the reasonable MSLP and peak wind of Rammasun should be 888hPa and 70-76m/s, which makes Rammasun the strongest typhoon ever made landfall in China's history. In order to intuitively investigate the real intensity of Ramasun, eyewall structures are compared with some historical extreme typhoons (hurricanes) such as Saomai(2006), Haiyan(2013) and Katrina(2005). Satellite images show that the dense overcast convection strength of Rammasun is stronger than those when Saomai and Katrina were in their peak intensities and before landing, but weaker than Haiyan. The

  19. Peak, multi-peak and broadband absorption in graphene-based one-dimensional photonic crystal

    NASA Astrophysics Data System (ADS)

    Miloua, R.; Kebbab, Z.; Chiker, F.; Khadraoui, M.; Sahraoui, K.; Bouzidi, A.; Medles, M.; Mathieu, C.; Benramdane, N.

    2014-11-01

    We theoretically investigate the possibility of enhancing light absorption in graphene-based one dimensional photonic crystal. We demonstrate that it is possible to achieve total light absorption at technologically important wavelengths using one-dimensional graphene-based photonic crystals. By means of the transfer matrix method, we investigate the effect of refractive indices and layer numbers on the optical response of the structure. We found that it is possible to achieve one peak, multi-peak or broadband, and complete optical absorption. As a result, the proposed photonic structures enable myriad potential applications such as photodetection, shielding and optical sensing.

  20. Expectable Earthquakes and their ground motions in the Van Norman Reservoirs Area

    USGS Publications Warehouse

    Wesson, R.L.; Page, R.A.; Boore, D.M.; Yerkes, R.F.

    1974-01-01

    The upper and lower Van Norman dams, in northwesternmost San Fernando Valley about 20 mi (32 km) northwest of downtown Los Angeles, were severely damaged during the 1971 San Fernando earthquake. An investigation of the geologic-seismologic setting of the Van Norman area indicates that an earthquake of at least M 7.7 may be expected in the Van Norman area. The expectable transitory effects in the Van Norman area of such an earthquake are as follows: peak horizontal acceleration of at least 1.15 g, peak velocity of displacement of 4.43 ft/sec (135 cm/sec), peak displacement of 2.3 ft (70 cm), and duration of shaking at accelerations greater than 0.05 g, 40 sec. A great earthquake (M 8+) on the San Andreas fault, 25 mi distant, also is expectable. Transitory effects in the Van Norman area from such an earthquake are estimated as follows: peak horizontal acceleration of 0.5 g, peak velocity of 1.97 ft/sec (60 cm/sec), displacement of 1.31 ft (40 cm), and duration of shaking at accelerations greater than 0.05 g, 80 sec. The permanent effects of the expectable local earthquake could include simultaneous fault movement at the lower damsite, the upper damsite, and the site proposed for a replacement dam halfway between the upper and lower dams. The maximum differential displacements due to such movements are estimated at 16.4 ft (5 m) at the lower damsite and about 9.6 ft (2.93 m) at the upper and proposed damsites. The 1971 San Fernando earthquake (M 6?) was accompanied by the most intense ground motions ever recorded instrumentally for a natural earthquake. At the lower Van Norman dam, horizontal accelerations exceeded 0.6 g, and shaking greater than 0.25 g lasted for about 13 see; at Pacoima dam, 6 mi (10 km) northeast of the lower dam, high-frequency peak horizontal accelerations of 1.25 g were recorded in two directions, and shaking greater than 0.25 g lasted for about 7 sec. Permanent effects of the earthquake include slope failures in the embankments of the upper

  1. Plasma inverse transition acceleration

    SciTech Connect

    Xie, Ming

    2001-06-18

    It can be proved fundamentally from the reciprocity theorem with which the electromagnetism is endowed that corresponding to each spontaneous process of radiation by a charged particle there is an inverse process which defines a unique acceleration mechanism, from Cherenkov radiation to inverse Cherenkov acceleration (ICA) [1], from Smith-Purcell radiation to inverse Smith-Purcell acceleration (ISPA) [2], and from undulator radiation to inverse undulator acceleration (IUA) [3]. There is no exception. Yet, for nearly 30 years after each of the aforementioned inverse processes has been clarified for laser acceleration, inverse transition acceleration (ITA), despite speculation [4], has remained the least understood, and above all, no practical implementation of ITA has been found, until now. Unlike all its counterparts in which phase synchronism is established one way or the other such that a particle can continuously gain energy from an acceleration wave, the ITA to be discussed here, termed plasma inverse transition acceleration (PITA), operates under fundamentally different principle. As a result, the discovery of PITA has been delayed for decades, waiting for a conceptual breakthrough in accelerator physics: the principle of alternating gradient acceleration [5, 6, 7, 8, 9, 10]. In fact, PITA was invented [7, 8] as one of several realizations of the new principle.

  2. Relativistic klystrons for high-gradient accelerators

    SciTech Connect

    Westenskow, G.A.; Aalberts, D.P.; Boyd, J.K.; Deis, G.A.; Houck, T.L.; Orzechowski, T.J.; Ryne, R.D.; Yu, S.S. ); Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Fowkes, W.R.; Hoag, H.A.; Koontz, R.F.; Lavine, T.L.; Loew, G.A.; Miller, R.H.; Ruth, R.D.; Vlieks, A.E.; Wang, J.W. ); Haimson, J.; Mecklen

    1990-09-05

    Experimental work is being performed by collaborators at LLNL, SLAC, and LBL to investigate relativistic klystrons as a possible rf power source for future high-gradient accelerators. We have learned how to overcome or previously reported problem of high power rf pulse shortening and have achieved peak rf power levels of 330 MW using an 11.4-GHz high-gain tube with multiple output structures. In these experiments the rf pulse is of the same duration as the beam current pulse. In addition, experiments have been performed on two short sections of a high-gradient accelerator using the rf power from a relativistic klystron. An average accelerating gradient of 84 MV/m has been achieved with 80-MW of rf power.

  3. Is cosmic acceleration slowing down?

    SciTech Connect

    Shafieloo, Arman; Sahni, Varun; Starobinsky, Alexei A.

    2009-11-15

    We investigate the course of cosmic expansion in its recent past using the Constitution SN Ia sample, along with baryon acoustic oscillations (BAO) and cosmic microwave background (CMB) data. Allowing the equation of state of dark energy (DE) to vary, we find that a coasting model of the universe (q{sub 0}=0) fits the data about as well as Lambda cold dark matter. This effect, which is most clearly seen using the recently introduced Om diagnostic, corresponds to an increase of Om and q at redshifts z < or approx. 0.3. This suggests that cosmic acceleration may have already peaked and that we are currently witnessing its slowing down. The case for evolving DE strengthens if a subsample of the Constitution set consisting of SNLS+ESSENCE+CfA SN Ia data is analyzed in combination with BAO+CMB data. The effect we observe could correspond to DE decaying into dark matter (or something else)

  4. Seismology and Earthquake Ground Motions of the August 24, 2014 M6 South Napa Earthquake

    NASA Astrophysics Data System (ADS)

    Kishida, T.; Wang, S.; Mazzoni, S.; Markam, C.; Lu, Y.; Bozorgnia, Y.; Mahin, S.; Bray, J.; Panagiotou, M.; Stewart, J. P.; Darragh, R. B.; Abrahamson, N. A.; Hollenback, J. C.; Gutierrez, C.; Chiou, B.; Muin, S.; Dreger, D. S.

    2014-12-01

    The M6.0 South Napa earthquake produced strong ground motions in the northern San Francisco Bay area. A total of 214 three-component uncorrected digital accelerograms were downloaded from the CESMD website and processed following the PEER standard procedure (Ancheta et al. 2014). Intense ground motions were recorded in the heavily damaged area of Napa with peak acceleration greater than 0.3 g. Pulse-like waveforms were observed in several of the velocity time series at the near-fault stations. Near-fault velocity time series were rotated into fault normal and fault parallel directions and then characterized as pulse-like or non pulse-like according to previous studies by Hayden et al. (2014), Shahi (2013), and Lu and Panagiotou (2014). The near-fault velocity time series at five stations contained pulses with periods within the expected range of 0.7 s to 2.0 s for soil sites (Bray et al. 2009). However, they also contained longer period pulses than the expected range. High-frequency spikes were recorded at Carquinez Bridge Geotechnical Array #1 (CBGA1) of approximately 1.0 g on the NS component. These spikes were in the S-wave portion and were consistently observed in the downhole arrays and several other sites along the same azimuth from the source. The spikes increase in amplitude both from the Hwy 37/Napa River East Geotechnical Array to CBGA1 and from a depth below 100 m to the surface. This suggests that the spikes could be a result of path effects and site amplification through the surficial soft soil deposits. However, these observations do not exclude the possibility of soil-structure interaction effects on the measured recordings. The 5% damped pseudo-spectral accelerations (PSA) from the recorded ground motions compared well to those estimated from the recent NGA-West2 GMPEs. The exceptions are that PSA is under predicted from 1 to 3 seconds at several near fault records due to the velocity pulses and for short periods at Carquinez Bridge where the large

  5. On correlation between zero bias conductance peaks and topological invariants in semiconductor Rashba nanowires

    NASA Astrophysics Data System (ADS)

    Nag, Amit; Sau, Jay

    The observed zero bias peak in tunneling conductance experiments on semiconductor Rashba nanowire is a signature of presence of Majorana zero modes. Characteristics of zero bias conductance peak (ZBCP) namely, height, width and peak splitting, are a function of microscopic parameters. Zero modes have finite splitting as a result of finiteness of the nanowire rendering the ground state only approximately topological i.e. zero modes are only approximately Majoranas. We calculate the scattering matrix topological invariant to quantify the quality of approximate Majorana modes and study its relation to observed characteristics of ZBCP. Furthermore we study the effect of dephasing on the topological invariant. Finally, we draw connection between the characteristics of the ZBCP and probability of observing non-Abelian statistics in proposed future experiments involving braiding of Majorana modes. Work is done in collaboration with Sankar Das Sarma and supported by LPS-MPO-CMTC, Microsoft Q, Univ. of Maryland startup grants and JQI-NSF-PFC.

  6. Ground vibrations from heavy freight trains

    NASA Astrophysics Data System (ADS)

    Dawn, T. M.

    1983-03-01

    Ground vibration from heavy freight trains on good quality welded track are found to have only a weak dependence on train speed above 30 km/h. At the site on which these tests were carried out a critical speed was found at which the vibration reached a peak. The frequencies of vibration produced appear to be functions of track and vehicle dimensions and the critical speed occurs at the coincidence of sleeper passage frequency and the total vehicle on track resonance frequency.

  7. Peak phosphorus - peak food? The need to close the phosphorus cycle.

    PubMed

    Rhodes, Christopher J

    2013-01-01

    The peak in the world production of phosphorus has been predicted to occur in 2033, based on world reserves of rock phosphate (URR) reckoned at around 24,000 million tonnes (Mt), with around 18,000 Mt remaining. This figure was reckoned-up to 71,000 Mt, by the USGS, in 2012, but a production maximum during the present century is still highly probable. There are complex issues over what the demand will be for phosphorus in the future, as measured against a rising population (from 7 billion to over 9 billion in 2050), and a greater per capita demand for fertiliser to grow more grain, in part to feed animals and meet a rising demand for meat by a human species that is not merely more populous but more affluent. As a counterweight to this, we may expect that greater efficiencies in the use of phosphorus - including recycling from farms and of human and animal waste - will reduce the per capita demand for phosphate rock. The unseen game changer is peak oil, since phosphate is mined and recovered using machinery powered by liquid fuels refined from crude oil. Hence, peak oil and peak phosphorus might appear as conjoined twins. There is no unequivocal case that we can afford to ignore the likelihood of a supply-demand gap for phosphorus occurring sometime this century, and it would be perilous to do so. PMID:23901632

  8. Peaking at Zero: Null Subjects and Other Indicators of Peak in Konni Texts.

    ERIC Educational Resources Information Center

    Cahill, Mike

    An analysis of story telling in Konni, a language spoken in Ghana, focused on how the climax of a story is characterized. The texts studied are six oral folk tales; two are appended, and portions of all are used as illustrations in the text of the report. First, the definition and characteristics of "peak," or climax of a story are discussed. This…

  9. Estimating youth locomotion ground reaction forces using an accelerometer-based activity monitor.

    PubMed

    Neugebauer, Jennifer M; Hawkins, David A; Beckett, Laurel

    2012-01-01

    To address a variety of questions pertaining to the interactions between physical activity, musculoskeletal loading and musculoskeletal health/injury/adaptation, simple methods are needed to quantify, outside a laboratory setting, the forces acting on the human body during daily activities. The purpose of this study was to develop a statistically based model to estimate peak vertical ground reaction force (pVGRF) during youth gait. 20 girls (10.9 ± 0.9 years) and 15 boys (12.5 ± 0.6 years) wore a Biotrainer AM over their right hip. Six walking and six running trials were completed after a standard warm-up. Average AM intensity (g) and pVGRF (N) during stance were determined. Repeated measures mixed effects regression models to estimate pVGRF from Biotrainer activity monitor acceleration in youth (girls 10-12, boys 12-14 years) while walking and running were developed. Log transformed pVGRF had a statistically significant relationship with activity monitor acceleration, centered mass, sex (girl), type of locomotion (run), and locomotion type-acceleration interaction controlling for subject as a random effect. A generalized regression model without subject specific random effects was also developed. The average absolute differences between the actual and predicted pVGRF were 5.2% (1.6% standard deviation) and 9% (4.2% standard deviation) using the mixed and generalized models, respectively. The results of this study support the use of estimating pVGRF from hip acceleration using a mixed model regression equation. PMID:23133564

  10. North Twin Peak in super resolution

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This pair of images shows the result of taking a sequence of 25 identical exposures from the Imager for Mars Pathfinder (IMP) of the northern Twin Peak, with small camera motions, and processing them with the Super-Resolution algorithm developed at NASA's Ames Research Center.

    The upper image is a representative input image, scaled up by a factor of five, with the pixel edges smoothed out for a fair comparison. The lower image allows significantly finer detail to be resolved.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    The super-resolution research was conducted by Peter Cheeseman, Bob Kanefsky, Robin Hanson, and John Stutz of NASA's Ames Research Center, Mountain View, CA. More information on this technology is available on the Ames Super Resolution home page at

    http://ic-www.arc.nasa.gov/ic/projects/bayes-group/ group/super-res/

  11. The Dielectric Wall Accelerator

    SciTech Connect

    Caporaso, George J.; Chen, Yu-Jiuan; Sampayan, Stephen E.

    2009-01-01

    The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

  12. Gamma rays from pulsar wind shock acceleration

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    1990-01-01

    A shock forming in the wind of relativistic electron-positron pairs from a pulsar, as a result of confinement by surrounding material, could convert part of the pulsar spin-down luminosity to high energy particles through first order Fermi acceleration. High energy protons could be produced by this mechanism both in supernova remnants and in binary systems containing pulsars. The pion-decay gamma-rays resulting from interaction of accelerated protons with surrounding target material in such sources might be observable above 70 MeV with EGRET (Energetic Gamma-Ray Experimental Telescope) and above 100 GeV with ground-based detectors. Acceleration of protons and expected gamma-ray fluxes from SN1987A, Cyg X-3 type sources and binary pulsars are discussed.

  13. High-speed video observations of natural cloud-to-ground lightning leaders - A statistical analysis

    NASA Astrophysics Data System (ADS)

    Campos, Leandro Z. S.; Saba, Marcelo M. F.; Warner, Tom A.; Pinto, Osmar; Krider, E. Philip; Orville, Richard E.

    2014-01-01

    The aim of this investigation is to analyze the phenomenology of positive and negative (stepped and dart) leaders observed in natural lightning from digital high-speed video recordings. For that intent we have used four different high-speed cameras operating at frame rates ranging from 1000 or 11,800 frames per second in addition to data from lightning locating systems (BrasilDat and NLDN). All the recordings were GPS time-stamped in order to avoid ambiguities in the analysis, allowing us to estimate the peak current of and the distance to each flash that was detected by one of the lightning locating systems. The data collection was done at different sites in south and southeastern of Brazil, southern Arizona and South Dakota, USA. A total of 62 negative stepped leaders, 76 negative dart leaders and 29 positive leaders were recorded and analyzed. From these data it was possible to calculate the two-dimensional speed of each observed leader, allowing us to obtain its statistical distribution and evaluate whether or not it is related to other characteristics of the associated flash. In the analyzed dataset, the speeds of positive leaders and negative dart leaders follow a lognormal distribution at the 0.05 level (according to the Shapiro-Wilk test). We have also analyzed how the two-dimensional leader speeds change as they approach ground through two different methodologies. The speed of positive leaders showed a clear tendency to increase while negative dart leaders tend to become slower as they approach ground. Negative stepped leaders, on the other hand, can either accelerate as they get closer to ground or present an irregular development (with no clear tendency) throughout their entire development. For all the three leader types no correlation has been found between the return stroke peak current and the average speed of the leader responsible for its initiation. We did find, however, that dart leaders preceded by longer interstroke intervals cannot present

  14. ACCELERATION RESPONSIVE SWITCH

    DOEpatents

    Chabrek, A.F.; Maxwell, R.L.

    1963-07-01

    An acceleration-responsive device with dual channel capabilities whereby a first circuit is actuated upon attainment of a predetermined maximum acceleration level and when the acceleration drops to a predetermined minimum acceleriltion level another circuit is actuated is described. A fluid-damped sensing mass slidably mounted in a relatively frictionless manner on a shaft through the intermediation of a ball bushing and biased by an adjustable compression spring provides inertially operated means for actuating the circuits. (AEC)

  15. Space Acceleration Measurement System

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This training video, presented by the Lewis Research Center's Space Experiments Division, gives a background and detailed instructions for preparing the space acceleration measurement system (SAMS) for use. The SAMS measures, conditions, and records forces of low gravity accelerations, and is used to determine the effect of these forces on various experiments performed in microgravity. Inertial sensors are used to measure positive and negative acceleration over a specified frequency range. The video documents the SAMS' uses in different configurations during shuttle missions.

  16. Wake field accelerators

    SciTech Connect

    Wilson, P.B.

    1986-02-01

    In a wake field accelerator a high current driving bunch injected into a structure or plasma produces intense induced fields, which are in turn used to accelerate a trailing charge or bunch. The basic concepts of wake field acceleration are described. Wake potentials for closed cavities and periodic structures are derived, as are wake potentials on a collinear path with a charge distribution. Cylindrically symmetric structures excited by a beam in the form of a ring are considered. (LEW)

  17. Accelerating into the future

    NASA Astrophysics Data System (ADS)

    Murray, Cherry

    2009-05-01

    Accelerator science has traditionally been associated with high-energy physics and nuclear physics. But the use of accelerators in other areas of science, as well as in medicine and industry, is steadily growing. Accelerators are now, for example, used to treat cancer using proton therapy, which can deposit radiation onto a tumour while causing much less damage to surrounding healthy tissue than with other treatment techniques.

  18. Optically pulsed electron accelerator

    DOEpatents

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  19. Optically pulsed electron accelerator

    DOEpatents

    Fraser, John S.; Sheffield, Richard L.

    1987-01-01

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  20. Miniaturization Techniques for Accelerators

    SciTech Connect

    Spencer, James E.

    2003-05-27

    The possibility of laser driven accelerators [1] suggests the need for new structures based on micromachining and integrated circuit technology because of the comparable scales. Thus, we are exploring fully integrated structures including sources, optics (for both light and particle) and acceleration in a common format--an accelerator-on-chip (AOC). Tests suggest a number of preferred materials and techniques but no technical or fundamental roadblocks at scales of order 1 {micro}m or larger.

  1. Evaluation of building fundamental periods and effects of local geology on ground motion parameters in the Siracusa area, Italy

    NASA Astrophysics Data System (ADS)

    Panzera, Francesco; D'Amico, Sebastiano; Lombardo, Giuseppe; Longo, Emanuela

    2016-07-01

    The Siracusa area, located in the southeastern coast of Sicily (Italy), is mainly characterized by the outcropping of a limestone formation. This lithotype, which is overlain by soft sediments such as sandy clays and detritus, can be considered as the local bedrock. Records of ambient noise, processed through spectral ratio techniques, were used to assess the dynamic properties of a sample survey of both reinforced concrete and masonry buildings. The results show that experimental periods of existing buildings are always lower than those proposed by the European seismic code. This disagreement could be related to the role played by stiff masonry infills, as well as the influence of adjacent buildings, especially in downtown Siracusa. Numerical modeling was also used to study the effect of local geology on the seismic site response of the Siracusa area. Seismic urban scenarios were simulated considering a moderate magnitude earthquake (December 13th, 1990) to assess the shaking level of the different outcropping formations. Spectral acceleration at different periods, peak ground acceleration, and velocity were obtained through a stochastic approach adopting an extended source model code. Seismic ground motion scenario highlighted that amplification mainly occurs in the sedimentary deposits that are widespread to the south of the study area as well as on some spot areas where coarse detritus and sandy clay outcrop. On the other hand, the level of shaking appears moderate in all zones with outcropping limestone and volcanics.

  2. Evaluation of building fundamental periods and effects of local geology on ground motion parameters in the Siracusa area, Italy

    NASA Astrophysics Data System (ADS)

    Panzera, Francesco; D'Amico, Sebastiano; Lombardo, Giuseppe; Longo, Emanuela

    2016-04-01

    The Siracusa area, located in the southeastern coast of Sicily (Italy), is mainly characterized by the outcropping of a limestone formation. This lithotype, which is overlain by soft sediments such as sandy clays and detritus, can be considered as the local bedrock. Records of ambient noise, processed through spectral ratio techniques, were used to assess the dynamic properties of a sample survey of both reinforced concrete and masonry buildings. The results show that experimental periods of existing buildings are always lower than those proposed by the European seismic code. This disagreement could be related to the role played by stiff masonry infills, as well as the influence of adjacent buildings, especially in downtown Siracusa. Numerical modeling was also used to study the effect of local geology on the seismic site response of the Siracusa area. Seismic urban scenarios were simulated considering a moderate magnitude earthquake (December 13th, 1990) to assess the shaking level of the different outcropping formations. Spectral acceleration at different periods, peak ground acceleration, and velocity were obtained through a stochastic approach adopting an extended source model code. Seismic ground motion scenario highlighted that amplification mainly occurs in the sedimentary deposits that are widespread to the south of the study area as well as on some spot areas where coarse detritus and sandy clay outcrop. On the other hand, the level of shaking appears moderate in all zones with outcropping limestone and volcanics.

  3. Effects of a contoured articular prosthetic device on tibiofemoral peak contact pressure: a biomechanical study

    PubMed Central

    Huber, Roland; Thermann, Hajo; Paessler, Hans H.; Skrbensky, Gobert

    2007-01-01

    Many middle-aged patients are affected by localized cartilage defects that are neither appropriate for primary, nor repeat biological repair methods, nor for conventional arthroplasty. This in vitro study aims to determine the peak contact pressure in the tibiofemoral joint with a partial femoral resurfacing device (HemiCAP®, Arthrosurface Inc., Franklin, MA, USA). Peak contact pressure was determined in eight fresh-frozen cadaveric specimens using a Tekscan sensor placed in the medial compartment above the menisci. A closed loop robotic knee simulator was used to test each knee in static stance positions (5°/15°/30°/45°) with body weight ground reaction force (GRF), 30° flexion with twice the body weight (2tBW) GRF and dynamic knee-bending cycles with body weight GRF. The ground reaction force was adjusted to the living body weight of the cadaver donor and maintained throughout all cycles. Each specimen was tested under four different conditions: Untreated, flush HemiCAP® implantation, 1-mm proud implantation and 20-mm defect. A paired sampled t test to compare means (significance, P ≤ 0.05) was used for statistical analysis. On average, no statistically significant differences were found in any testing condition comparing the normal knee with flush device implantation. With the 1-mm proud implant, statistically significant increase of peak contact pressures of 217% (5° stance), 99% (dynamic knee bending) and 90% (30° stance with 2tBW) compared to the untreated condition was seen. No significant increase of peak contact pressure was evaluated with the 20-mm defect. The data suggests that resurfacing with the HemiCAP® does not lead to increased peak contact pressure with flush implantation. However, elevated implantation results in increased peak contact pressure and might be biomechanically disadvantageous in an in vivo application. PMID:17934718

  4. Accelerator Facilities for Radiation Research

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.

    1999-01-01

    HSRP Goals in Accelerator Use and Development are: 1.Need for ground-based heavy ion and proton facility to understand space radiation effects discussed most recently by NAS/NRC Report (1996). 2. Strategic Program Goals in facility usage and development: -(1) operation of AGS for approximately 600 beam hours/year; (2) operation of Loma Linda University (LLU) proton facility for approximately 400 beam hours/year; (3) construction of BAF facility; and (4) collaborative research at HIMAC in Japan and with other existing or potential international facilities. 3. MOA with LLU has been established to provide proton beams with energies of 40-250 important for trapped protons and solar proton events. 4. Limited number of beam hours available at Brookhaven National Laboratory's (BNL) Alternating Gradient Synchrotron (AGS).

  5. A new attenuation model of near-fault ground motions with consideration of the hanging wall effect in the Wenchuan earthquake

    NASA Astrophysics Data System (ADS)

    Peng, Lei; Xie, Lili; Hu, Jinjun; Wang, Dong

    2011-09-01

    The hanging wall effect is an important factor that impacts the characteristics of strong ground motions in near-fault areas. Based on a residual analysis of ground motion parameters characterizing the hanging wall effect and in recognition of the nature of the effect, many models have been developed. In this study, after a comprehensive analysis of two existing models, a new model is proposed and used to model the hanging wall effect in horizontal peak ground acceleration (PGAH) and spectral acceleration (SAH) at a period of 0.1 s in the Wenchuan earthquake. Finally, comparisons between the modeling results of the hanging wall effect in the Wenchuan earthquake and the results predicted by using Abrahamson and Silva's NGA model (AS NGA) indicate that the AS NGA model predicts a much higher hanging wall effect than the model developed in this paper. Furthermore, the AS NGA model predicts a large hanging wall effect even at great distances, while the proposed model more accurately captures the trend of the effect.

  6. Particle acceleration in flares

    NASA Technical Reports Server (NTRS)

    Benz, Arnold O.; Kosugi, Takeo; Aschwanden, Markus J.; Benka, Steve G.; Chupp, Edward L.; Enome, Shinzo; Garcia, Howard; Holman, Gordon D.; Kurt, Victoria G.; Sakao, Taro

    1994-01-01

    Particle acceleration is intrinsic to the primary energy release in the impulsive phase of solar flares, and we cannot understand flares without understanding acceleration. New observations in soft and hard X-rays, gamma-rays and coherent radio emissions are presented, suggesting flare fragmentation in time and space. X-ray and radio measurements exhibit at least five different time scales in flares. In addition, some new observations of delayed acceleration signatures are also presented. The theory of acceleration by parallel electric fields is used to model the spectral shape and evolution of hard X-rays. The possibility of the appearance of double layers is further investigated.

  7. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-09-02

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  8. Accelerator-based BNCT.

    PubMed

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases. PMID:24365468

  9. Acceleration of polarized protons in circular accelerators

    SciTech Connect

    Courant, E.D.; Ruth, R.D.

    1980-09-12

    The theory of depolarization in circular accelerators is presented. The spin equation is first expressed in terms of the particle orbit and then converted to the equivalent spinor equation. The spinor equation is then solved for three different situations: (1) a beam on a flat top near a resonance, (2) uniform acceleration through an isolated resonance, and (3) a model of a fast resonance jump. Finally, the depolarization coefficient, epsilon, is calculated in terms of properties of the particle orbit and the results are applied to a calculation of depolarization in the AGS.

  10. Surface sensitivity of elastic peak electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Jablonski, A.

    2016-08-01

    New theoretical model describing the sampling depth of elastic peak electron spectroscopy (EPES) has been proposed. Surface sensitivity of this technique can be generally identified with the maximum depth reached by trajectories of elastically backscattered electrons. A parameter called the penetration depth distribution function (PDDF) has been proposed for this description. Two further parameters are descendant from this definition: the mean penetration depth (MPD) and the information depth (ID). From the proposed theory, relatively simple analytical expressions describing the above parameters can be derived. Although the Monte Carlo simulations can be effectively used to estimate the sampling depth of EPES, this approach may require a considerable amount of computations. In contrast, the analytical model proposed here (AN) is very fast and provides the parameters PDDF, MPD and ID that very well compare with results of MC simulations. As follows from detailed comparisons performed for four elements (Al, Ni, Pd and Au), the AN model practically reproduced complicated emission angle dependences of the MPDs and the IDs, correctly indicating numerous maximum and minimum positions. In the energy range from 200 eV to 5 keV, the averaged percentage differences between MPDs obtained from the MC and the AN models were close to 4%. An important conclusion resulting from the present studies refers to the procedure of determination of the inelastic mean free path (IMFP) from EPES. Frequently, the analyzed sample is deposited as a thin overlayer on a smooth substrate. From an analysis of the presently obtained IDs, is follows that 99% of trajectories in analyzed experimental configurations reaches depth not exceeding 2.39 in units of IMFP. Thus, one can postulate that a safe minimum thickness of an overlayer should be larger than about 3 IMFPs. For example, the minimum thickness of an Al overlayer shoud be about 8 nm at 5000 eV.

  11. Research Opportunities at Storm Peak Laboratory

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; McCubbin, I. B.

    2006-12-01

    The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located on the west summit of Mt. Werner in the Park Range near Steamboat Springs, Colorado at an elevation of 3210 m MSL (Borys and Wetzel, 1997). SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. The ridge-top location produces almost daily transition from free tropospheric to boundary layer air which occurs near midday in both summer and winter seasons. Long-term observations at SPL document the role of orographically induced mixing and convection on vertical pollutant transport and dispersion. During winter, SPL is above cloud base 25% of the time, providing a unique capability for studying aerosol-cloud interactions (Borys and Wetzel, 1997). A comprehensive set of continuous aerosol measurements was initiated at SPL in 2002. SPL includes an office-type laboratory room for computer and instrumentation setup with outside air ports and cable access to the roof deck, a cold room for precipitation and cloud rime ice sample handling and ice crystal microphotography, a 150 m2 roof deck area for outside sampling equipment, a full kitchen and two bunk rooms with sleeping space for nine persons. The laboratory is currently well equipped for aerosol and cloud measurements. Particles are sampled from an insulated, 15 cm diameter manifold within approximately 1 m of its horizontal entry point through an outside wall. The 4 m high vertical section outside the building is capped with an inverted can to exclude large particles.

  12. Estimating ground water discharge by hydrograph separation.

    PubMed

    Hannula, Steven R; Esposito, Kenneth J; Chermak, John A; Runnells, Donald D; Keith, David C; Hall, Larry E

    2003-01-01

    Iron Mountain is located in the West Shasta Mining District in California. An investigation of the generation of acid rock drainage and metals loading to Boulder Creek at Iron Mountain was conducted. As part of that investigation, a hydrograph separation technique was used to determine the contribution of ground water to total flow in Boulder Creek. During high-flow storm events in the winter months, peak flow in Boulder Creek can exceed 22.7 m3/sec, and comprises surface runoff, interflow, and ground water discharge. A hydrograph separation technique was used to estimate ground water discharge into Boulder Creek during high-flow conditions. Total ground water discharge to the creek approaches 0.31 m3/sec during the high-flow season. The hydrograph separation technique combined with an extensive field data set provided reasonable estimates of ground water discharge. These estimates are useful for other investigations, such as determining a corresponding metals load from the metal-rich ground water found at Iron Mountain and thus contributing to remedial alternatives. PMID:12772830

  13. Observation and prediction of dynamic ground strains, tilts, and torsions caused by the Mw 6.0 2004 Parkfield, California, earthquake and aftershocks, derived from UPSAR array observations

    USGS Publications Warehouse

    Spudich, P.; Fletcher, Joe B.

    2008-01-01

    The 28 September 2004 Parkfield, California, earthquake (Mw 6.0) and four aftershocks (Mw 4.7-5.1) were recorded on 12 accelerograph stations of the U.S. Geological Survey Parkfield seismic array (UPSAR), an array of three-component accelerographs occupying an area of about 1 km2 located 8.8 km from the San Andreas fault. Peak horizontal acceleration and velocity at UPSAR during the mainshock were 0.45g and 27 cm/sec, respectively. We determined both time-varying and peak values of ground dilatations, shear strains, torsions, tilts, torsion rates, and tilt rates by applying a time-dependent geodetic analysis to the observed array displacement time series. Array-derived dilatations agree fairly well with point measurements made on high sample rate recordings of the Parkfield-area dilatometers (Johnston et al., 2006). Torsion Fourier amplitude spectra agree well with ground velocity spectra, as expected for propagating plane waves. A simple predictive relation, using the predicted peak velocity from the Boore-Atkinson ground-motion prediction relation (Boore and Atkinson, 2007) scaled by a phase velocity of 1 km/sec, predicts observed peak Parkfield and Chi-Chi rotations (Huang, 2003) well. However, rotation rates measured during Mw 5 Ito, Japan, events observed on a gyro sensor (Takeo, 1998) are factors of 5-60 greater than those predicted by our predictive relation. This discrepancy might be caused by a scale dependence in rotation, with rotations measured over a short baseline exceeding those measured over long baselines. An alternative hypothesis is that events having significant non-double-couple mechanisms, like the Ito events, radiate much stronger rotations than double-couple events. If this is true, then rotational observations might provide an important source of new information for monitoring seismicity in volcanic areas.

  14. Observation and Prediction of Dynamic Ground Strains, Tilts and Torsions Caused by the M6.0 2004 Parkfield, California, Earthquake and Aftershocks Derived From UPSAR Array Observations

    NASA Astrophysics Data System (ADS)

    Spudich, P.; Fletcher, J. B.

    2008-12-01

    The September 28, 2004, Parkfield, California, earthquake (Mw 6.0) and four aftershocks (Mw 4.7 - 5.1) were recorded on 12 accelerograph stations of the UPSAR seismic array, an array of three-component accelerographs occupying an area of about 1 square km located 8.8 km from the San Andreas fault. Peak horizontal acceleration and velocity at UPSAR during the mainshock were 0.45 g and 0.27 m/s, respectively. We determined both time-varying and peak values of ground dilatations, shear strains, torsions, tilts, torsion rates, and tilt rates by applying a time-dependent geodetic analysis to the observed array displacement time series. Array-derived dilatations agree fairly well with point measurements made on high sample rate recordings of the Parkfield-area dilatometers (Johnston et al., 2006). Torsion Fourier amplitude spectra agree well with ground velocity spectra, as expected for propagating plane waves. A simple predictive relation, using predicted peak velocity from the Boore-Atkinson (2007) ground motion prediction relation scaled by a phase velocity of 1 km/s, predicts observed peak Parkfield and Chi-Chi rotations (Huang, 2003) well. However, rotation rates measured during Mw 5 Ito, Japan, events observed on a gyro sensor (Takeo, 1998) are factors of 5 - 60 greater than predicted by our predictive relation. This discrepancy might be caused by a scale-dependence in rotation, with rotations measured over a short baseline exceeding those measured over long baselines. An alternative hypothesis is that events having significant non-double-couple mechanisms, like the Ito events, radiate much stronger rotations than double-couple events. If this is true, then rotational observations might provide an important source of new information for monitoring seismicity in volcanic areas.

  15. Intense coherent terahertz generation from accelerator-based sources

    NASA Astrophysics Data System (ADS)

    Hama, Hiroyuki; Yasuda, Mafuyu; Kawai, Masayuki; Hinode, Fujio; Nanbu, Kenichi; Miyahara, Fusashi

    2011-05-01

    The development of terahertz (THz) technology and science relevant to accelerator-based sources has been rapid, based on laser and semiconductor physics. To assure further progress of this scientific field, extremely intense radiation, involving gigawatt-class peak power, is needed. In addition to discussing the prospects for typical accelerator-based THz sources, such as coherent synchrotron radiation (CSR) and free electron lasers (FELs), novel, advanced THz sources employing isochronous-ring and bunched-FEL approaches are proposed.

  16. Electron injector for compact staged high energy accelerator

    NASA Astrophysics Data System (ADS)

    Audet, T. L.; Desforges, F. G.; Maitrallain, A.; Dufrénoy, S. Dobosz; Bougeard, M.; Maynard, G.; Lee, P.; Hansson, M.; Aurand, B.; Persson, A.; González, I. Gallardo; Monot, P.; Wahlström, C.-G.; Lundh, O.; Cros, B.

    2016-09-01

    An electron injector for multi-stage laser wakefield experiments is presented. It consists of a variable length gas cell of small longitudinal dimension (⩽ 10 mm). The gas filling process in this cell was characterized both experimentally and with fluid simulation. Electron acceleration experiments were performed at two different laser facilities. Results show low divergence and low pointing fluctuation electron bunches suitable for transport to a second stage, and a peaked energy distribution suitable for injection into the second stage wakefield accelerator.

  17. Electrical grounding prong socket

    DOEpatents

    Leong, Robert

    1991-01-01

    The invention is a socket for a grounding prong used in a three prong electrical plug and a receptacle for the three prong plug. The socket being sufficiently spacious to prevent the socket from significantly stretching when a larger, U-shaped grounding prong is inserted into the socket, and having a ridge to allow a snug fit when a smaller tubular shape grounding prong is inserted into the socket.

  18. Acute Whole-Body Vibration does not Facilitate Peak Torque and Stretch Reflex in Healthy Adults

    PubMed Central

    Yeung, Ella W.; Lau, Cheuk C.; Kwong, Ada P.K.; Sze, Yan M.; Zhang, Wei Y.; Yeung, Simon S.

    2014-01-01

    The acute effect of whole-body vibration (WBV) training may enhance muscular performance via neural potentiation of the stretch reflex. The purpose of this study was to investigate if acute WBV exposure affects the stretch induced knee jerk reflex [onset latency and electromechanical delay (EMD)] and the isokinetic knee extensor peak torque performance. Twenty-two subjects were randomly assigned to the intervention or control group. The intervention group received WBV in a semi-squat position at 30° knee flexion with an amplitude of 0.69 mm, frequency of 45 Hz, and peak acceleration of 27.6 m/s2 for 3 minutes. The control group underwent the same semii-squatting position statically without exposure of WBV. Two-way mixed repeated measures analysis of variance revealed no significant group effects differences on reflex latency of rectus femoris (RF) and vastus lateralis (VL; p = 0.934 and 0.935, respectively) EMD of RF and VL (p = 0.474 and 0.551, respectively) and peak torque production (p = 0.483) measured before and after the WBV. The results of this study indicate that a single session of WBV exposure has no potentiation effect on the stretch induced reflex and peak torque performance in healthy young adults. Key Points There is no acute potentiation of stretch reflex right after whole body vibration. Acute whole body vibration does not improve mus-cle peak torque performance in healthy young adults. PMID:24570602

  19. The short-lived (<2 minutes) acceleration of protons to >13 GeV in association with solar flares.

    NASA Astrophysics Data System (ADS)

    McCracken, Ken; Shea, Margaret Ann; Smart, Don

    2016-04-01

    There have been 72 occasions in the past 75 years when solar cosmic rays have been accelerated to >1 GeV in association with large solar flares. The largest such so called "ground level enhancement" (GLE) occurred on 23 February, 1956. We have recently gained access to the original real-time photographic record for that GLE obtained by the recording ionization meter located at Huancayo, Peru. The geomagnetic field excludes all cosmic rays <13GeV from this location, and consequently this record provides a record of the arrival at earth of the highly relativistic 13-20 GeV particles accelerated at the sun. While all previous studies have used 6 minute average data, examination shows that the original record is capable of providing 1 minute time resolution of the cosmic ray intensity during the GLE . The resulting dependence of intensity upon time shows considerable detail that was obscured by the coarser time resolution used in the past. Thus (1) The GLE commenced only 3 minutes after the peak flare intensity in Hα , this being consistent with the 4 minute delay associated with propagation along the "Parker" heliospheric field; (2) the cosmic ray intensity rose to within 10% of its peak in 2 minutes; (3) Peak intensity persisted for only 1 minute; and (4) the intensity had decreased to 50% of the peak value 5 minutes after the commencement of the GLE. There being no velocity dispersion at these energies, and little pitch angle scattering, we take the view that the intensity profile at earth is a close representation of the intensity-time profile of these newly accelerated cosmic rays at the sun. If so, these data impose strict tests on any putative acceleration model, and provide information on the physical properties in the vicinity of the source. In particular, the data show that the model must predict (a) that ambient protons can be accelerated to >13GeV in < 2 minutes; (b) that the protons have easy access to open solar fields; and (c) that the acceleration (or

  20. Accelerator Physics Working Group Summary

    NASA Astrophysics Data System (ADS)

    Li, D.; Uesugi, T.; Wildnerc, E.

    2010-03-01

    The Accelerator Physics Working Group addressed the worldwide R&D activities performed in support of future neutrino facilities. These studies cover R&D activities for Super Beam, Beta Beam and muon-based Neutrino Factory facilities. Beta Beam activities reported the important progress made, together with the research activity planned for the coming years. Discussion sessions were also organized jointly with other working groups in order to define common ground for the optimization of a future neutrino facility. Lessons learned from already operating neutrino facilities provide key information for the design of any future neutrino facility, and were also discussed in this meeting. Radiation damage, remote handling for equipment maintenance and exchange, and primary proton beam stability and monitoring were among the important subjects presented and discussed. Status reports for each of the facility subsystems were presented: proton drivers, targets, capture systems, and muon cooling and acceleration systems. The preferred scenario for each type of possible future facility was presented, together with the challenges and remaining issues. The baseline specification for the muon-based Neutrino Factory was reviewed and updated where required. This report will emphasize new results and ideas and discuss possible changes in the baseline scenarios of the facilities. A list of possible future steps is proposed that should be followed up at NuFact10.

  1. Quiet Spike(TradeMark) Build-up Ground Vibration Testing Approach

    NASA Technical Reports Server (NTRS)

    Spivey, Natalie D.; Herrera, Claudia Y.; Truax, Roger; Pak, Chan-gi; Freund, Donald

    2007-01-01

    Flight tests of Gulfstream Aerospace Corporation s Quiet Spike(TradeMark) hardware were recently completed on the NASA Dryden Flight Research Center F-15B airplane. NASA Dryden uses a modified F-15B airplane as a testbed aircraft to cost-effectively fly flight research experiments that are typically mounted underneath the F-15B airplane, along the fuselage centerline. For the Quiet Spike(TradeMark) experiment, however, instead of a centerline mounting, a relatively long forward-pointing boom was attached to the radar bulkhead of the F-15B airplane. The Quiet Spike(TradeMark) experiment is a stepping-stone to airframe structural morphing technologies designed to mitigate the sonic-boom strength of business jets over land. The Quiet Spike(TradeMark) boom is a concept in which an aircraft s noseboom would be extended prior to supersonic acceleration. This morphing effectively lengthens the aircraft, thus reducing the peak sonic-boom amplitude, but is also expected to partition the otherwise strong bow shock into a series of reduced-strength, noncoalescing shocklets. Prior to flying the Quiet Spike(TradeMark) experiment on the F-15B airplane several ground vibration tests were required to understand the Quiet Spike(TradeMark) modal characteristics and coupling effects with the F-15B airplane. However, due to the flight hardware availability and compressed schedule requirements, a "traditional" ground vibration test of the mated F-15B Quiet Spike(TradeMark) ready-for- flight configuration did not leave sufficient time available for the finite element model update and flutter analyses before flight testing. Therefore, a "nontraditional" ground vibration testing approach was taken. This paper provides an overview of each phase of the "nontraditional" ground vibration testing completed for the Quiet Spike(TradeMark) project which includes the test setup details, instrumentation layout, and modal results obtained in support of the structural dynamic modeling and flutter

  2. Long Period Ground Motion at Bedrock Level in Delhi City from Himalayan Earthquake Scenarios

    NASA Astrophysics Data System (ADS)

    Parvez, Imtiyaz A.; Romanelli, Fabio; Panza, Giuliano F.

    2011-03-01

    Delhi, the capital of India, is prone to severe seismic hazards, not only from local events but also from Himalayan earthquakes at distances of 250-300 km. Standard techniques are not sufficiently reliable to completely characterize the seismic hazards in this case due to the difficulty of predicting the occurrence of earthquakes (frequency-magnitude relations) and of properly treating the propagation of their effects (attenuation laws), especially their long-period components. In order to give a sound description of the seismic ground motion due to an earthquake in such a given range of distances (and magnitudes), we use modelling techniques developed from physics of the seismic source generation and propagation processes. Such models take into account the directivity effect of rupture propagation and the attenuation of (long-period) ground motions. The generated ground motion scenarios permit us to build a very important knowledge base to be fruitfully used by civil engineers, since long period ground motions, especially if amplified by deep sedimentary basins, can represent a severe threat for large scale structures (e.g. lifelines and bridges) and tall buildings, which are widespread in fast-growing megacities. In this study, we simulate the ground motion, at bedrock level, in Delhi city, for an earthquake scenario corresponding to a source of Mw = 8.0 located in the central seismic gap of Himalayas, at an epicentral distance of about 300 km from Delhi city. By means of several parametric studies, we simulate the time histories using Size Scaled Point Source, Space and Time Scaled Point Source and Extended Source models. Together with the complete time histories (displacements, velocities and accelerations, from which the peak amplitudes have been extracted), we have also used the displacement response spectrum to characterize the seismic input at Delhi. Not only is the displacement response spectrum of great significance to modern displacement-based design

  3. A Bayesian and Physics-Based Ground Motion Parameters Map Generation System

    NASA Astrophysics Data System (ADS)

    Ramirez-Guzman, L.; Quiroz, A.; Sandoval, H.; Perez-Yanez, C.; Ruiz, A. L.; Delgado, R.; Macias, M. A.; Alcántara, L.

    2014-12-01

    We present the Ground Motion Parameters Map Generation (GMPMG) system developed by the Institute of Engineering at the National Autonomous University of Mexico (UNAM). The system delivers estimates of information associated with the social impact of earthquakes, engineering ground motion parameters (gmp), and macroseismic intensity maps. The gmp calculated are peak ground acceleration and velocity (pga and pgv) and response spectral acceleration (SA). The GMPMG relies on real-time data received from strong ground motion stations belonging to UNAM's networks throughout Mexico. Data are gathered via satellite and internet service providers, and managed with the data acquisition software Earthworm. The system is self-contained and can perform all calculations required for estimating gmp and intensity maps due to earthquakes, automatically or manually. An initial data processing, by baseline correcting and removing records containing glitches or low signal-to-noise ratio, is performed. The system then assigns a hypocentral location using first arrivals and a simplified 3D model, followed by a moment tensor inversion, which is performed using a pre-calculated Receiver Green's Tensors (RGT) database for a realistic 3D model of Mexico. A backup system to compute epicentral location and magnitude is in place. A Bayesian Kriging is employed to combine recorded values with grids of computed gmp. The latter are obtained by using appropriate ground motion prediction equations (for pgv, pga and SA with T=0.3, 0.5, 1 and 1.5 s ) and numerical simulations performed in real time, using the aforementioned RGT database (for SA with T=2, 2.5 and 3 s). Estimated intensity maps are then computed using SA(T=2S) to Modified Mercalli Intensity correlations derived for central Mexico. The maps are made available to the institutions in charge of the disaster prevention systems. In order to analyze the accuracy of the maps, we compare them against observations not considered in the

  4. Scaling FFAG accelerator for muon acceleration

    SciTech Connect

    Lagrange, JB.; Planche, T.; Mori, Y.

    2011-10-06

    Recent developments in scaling fixed field alternating gradient (FFAG) accelerators have opened new ways for lattice design, with straight sections, and insertions like dispersion suppressors. Such principles and matching issues are detailed in this paper. An application of these new concepts is presented to overcome problems in the PRISM project.

  5. Physics-based Broadband Ground Motion Simulations for Probable M>7.0 earthquakes in the Marmara Sea Region (Turkey)

    NASA Astrophysics Data System (ADS)

    Akinci, Aybige; Aochi, Hideo; Herrero, Andre; Pischiutta, Marta; Karanikas, Dimitris

    2016-04-01

    The city of Istanbul is characterized by one of the highest levels of seismic risk in Europe and the Mediterranean region. The important source of the increased risk in Istanbul is the remarkable probability of the occurrence of a large earthquake, which stands at about 65% during the coming years due to the existing seismic gap and the post-1999 earthquake stress transfer at the western portion of the North Anatolian Fault Zone (NAFZ). In this study, we have simulated hybrid broadband time histories from two selected scenario earthquakes having magnitude M>7.0 in the Marmara Sea within 10-20 km of Istanbul believed to have generated devastating 1509 event in the region. The physics-based rupture scenarios, which may be an indication of potential future events, are adopted to estimate the ground motion characteristics and its variability in the region. Two simulation techniques (a full 3D wave propagation method to generate low-frequency seismograms, <~1 Hz and a stochastic technique to simulate high-frequency seismograms, >1Hz) are used to compute more realistic time series associated with scenario earthquakes having magnitudes Mw >7.0 in the Marmara Sea Region. A dynamic rupture is generated and computed with a boundary integral equation method and the propagation in the medium is realized through a finite difference approach (Aochi and Ulrich, 2015). The high frequency radiation is computed using stochastic finite-fault model approach based on a dynamic corner frequency (Motazedian and Atkinson, 2005; Boore, 2009). The results from the two simulation techniques are then merged by performing a weighted summation at intermediate frequencies to calculate broadband synthetic time series. The hybrid broadband ground motions computed with the proposed approach are validated by comparing peak ground acceleration (PGA), peak ground velocity (PGV), and spectral acceleration (SA) with recently proposed ground motion prediction equations (GMPE) in the region. Our

  6. ITALIAN PEAK AND ITALIAN PEAK MIDDLE ROADLESS AREAS, IDAHO AND MONTANA.

    USGS Publications Warehouse

    Skipp, Betty; Lambeth, Robert H.

    1984-01-01

    The Italian Peak and Italian Peak Middle Roadless Areas, in southwestern Montana and east-central Idaho, contain areas of probable mineral-resource potential based on combined geologic, geophysical, and geochemical studies and prospect examination. Small areas along the western, southern, and northeastern boundaries of the roadless areas have probable mineral resource potential for zinc, lead, silver, and uranium. An area of probable resource potential just east of and including a part of the Birch Creek mining district, may contain stratabound and fault-controlled silver and base metals, even though geochemical anomalies are low, and extensive prospecting has not identified any significant mineralization. The roadless areas are a part of the overthrust belt, and oil and gas possibilities must be assessed.

  7. D-peaks: a visual tool to display ChIP-seq peaks along the genome.

    PubMed

    Brohée, Sylvain; Bontempi, Gianluca

    2012-01-01

    ChIP-sequencing is a method of choice to localize the positions of protein binding sites on DNA on a whole genomic scale. The deciphering of the sequencing data produced by this novel technique is challenging and it is achieved by their rigorous interpretation using dedicated tools and adapted visualization programs. Here, we present a bioinformatics tool (D-peaks) that adds several possibilities (including, user-friendliness, high-quality, relative position with respect to the genomic features) to the well-known visualization browsers or databases already existing. D-peaks is directly available through its web interface http://rsat.ulb.ac.be/dpeaks/ as well as a command line tool. PMID:23132505

  8. Dosimetric response of radiochromic films to protons of low energies in the Bragg peak region

    NASA Astrophysics Data System (ADS)

    Battaglia, M. C.; Schardt, D.; Espino, J. M.; Gallardo, M. I.; Cortés-Giraldo, M. A.; Quesada, J. M.; Lallena, A. M.; Miras, H.; Guirado, D.

    2016-06-01

    One of the major advantages of proton or ion beams, applied in cancer treatment, is their excellent depth-dose profile exhibiting a low dose in the entrance channel and a distinct dose maximum (Bragg peak) near the end of range in tissue. In the region of the Bragg peak, where the protons or ions are almost stopped, experimental studies with low-energy particle beams and thin biological samples may contribute valuable information on the biological effectiveness in the stopping region. Such experiments, however, require beam optimization and special dosimetry techniques for determining the absolute dose and dose homogeneity for very thin biological samples. At the National Centre of Accelerators in Seville, one of the beam lines at the 3 MV Tandem Accelerator was equipped with a scattering device, a special parallel-plate ionization chamber with very thin electrode foils and target holders for cell cultures. In this work, we present the calibration in absolute dose of EBT3 films [Gafchromic radiotherapy films, http://www.ashland.com/products/gafchromic-radiotherapy-films] for proton energies in the region of the Bragg peak, where the linear energy transfer increases and becomes more significant for radiobiology studies, as well as the response of the EBT3 films for different proton energy values. To irradiate the films in the Bragg peak region, the energy of the beam was degraded passively, by interposing Mylar foils of variable thickness to place the Bragg peak inside the active layer of the film. The results obtained for the beam degraded in Mylar foils are compared with the dose calculated by means of the measurement of the beam fluence with an ionization chamber and the energy loss predicted by srim2008 code.

  9. Automatic quality assessment and peak identification of auditory brainstem responses with fitted parametric peaks.

    PubMed

    Valderrama, Joaquin T; de la Torre, Angel; Alvarez, Isaac; Segura, Jose Carlos; Thornton, A Roger D; Sainz, Manuel; Vargas, Jose Luis

    2014-05-01

    The recording of the auditory brainstem response (ABR) is used worldwide for hearing screening purposes. In this process, a precise estimation of the most relevant components is essential for an accurate interpretation of these signals. This evaluation is usually carried out subjectively by an audiologist. However, the use of automatic methods for this purpose is being encouraged nowadays in order to reduce human evaluation biases and ensure uniformity among test conditions, patients, and screening personnel. This article describes a new method that performs automatic quality assessment and identification of the peaks, the fitted parametric peaks (FPP). This method is based on the use of synthesized peaks that are adjusted to the ABR response. The FPP is validated, on one hand, by an analysis of amplitudes and latencies measured manually by an audiologist and automatically by the FPP method in ABR signals recorded at different stimulation rates; and on the other hand, contrasting the performance of the FPP method with the automatic evaluation techniques based on the correlation coefficient, FSP, and cross correlation with a predefined template waveform by comparing the automatic evaluations of the quality of these methods with subjective evaluations provided by five experienced evaluators on a set of ABR signals of different quality. The results of this study suggest (a) that the FPP method can be used to provide an accurate parameterization of the peaks in terms of amplitude, latency, and width, and (b) that the FPP remains as the method that best approaches the averaged subjective quality evaluation, as well as provides the best results in terms of sensitivity and specificity in ABR signals validation. The significance of these findings and the clinical value of the FPP method are highlighted on this paper. PMID:24661606

  10. Ground truth versus no ground truth

    NASA Technical Reports Server (NTRS)

    Torbert, G. B.

    1970-01-01

    The area of study was the southeastern Arizona test site and three areas within the site were studied in detail: Safford, Point of Pines, and Fort Apache-White River. These areas have terrain contrast ranging from flat arid regions to high alpine mountains. Data were obtained from the Apollo 9 photographic missions, high altitude aerial photography, and simulated ERTS-A data from high altitude aircraft. Various monoscopic and steroscopic devices were used to analyze the features, and film density variations were studied. No ground-based data were permitted. Thematic maps were prepared for geology, geomorphology, vegetation, hydrology, and soils. Interpreted boundaries were delineated, with no collaborative data used in the interpretation. Ground-based data were gathered during the overflight of high altitude aerial photography. A further study was made using the ground truth, and the data gathered on the ground were compared with original mapping. 80% to 85% of the interpretations in the areas checked were correct. It was proved that it is possible to monitor gross features of the vigor of crop lands and vegetative cover, to type soils and classify geologic features, and to determine hydrologic conditions.

  11. Accelerators (4/5)

    ScienceCinema

    None

    2011-10-06

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  12. J-PARC Accelerator

    SciTech Connect

    Yamazaki, Yoshishige

    2008-02-21

    The Japan Proton Accelerator Research Complex (J-PARC) is under construction in Tokai site. The linac beam commissioning started last fall, while the beam commissioning of the 3-GeV Rapid-Cycling Synchrotron (RCS) will start this fall. The status of the J-PARC accelerator is reported with emphasis on the technical development accomplished for the J-PARC.

  13. Particle Acceleration in Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi

    2005-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma ray burst (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments.

  14. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  15. Accelerators Beyond The Tevatron?

    SciTech Connect

    Lach, Joseph

    2010-07-01

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?

  16. Microscale acceleration history discriminators

    DOEpatents

    Polosky, Marc A.; Plummer, David W.

    2002-01-01

    A new class of micromechanical acceleration history discriminators is claimed. These discriminators allow the precise differentiation of a wide range of acceleration-time histories, thereby allowing adaptive events to be triggered in response to the severity (or lack thereof) of an external environment. Such devices have applications in airbag activation, and other safety and surety applications.

  17. KEK digital accelerator

    NASA Astrophysics Data System (ADS)

    Iwashita, T.; Adachi, T.; Takayama, K.; Leo, K. W.; Arai, T.; Arakida, Y.; Hashimoto, M.; Kadokura, E.; Kawai, M.; Kawakubo, T.; Kubo, Tomio; Koyama, K.; Nakanishi, H.; Okazaki, K.; Okamura, K.; Someya, H.; Takagi, A.; Tokuchi, A.; Wake, M.

    2011-07-01

    The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA) is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR) ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

  18. Accelerators (5/5)

    ScienceCinema

    None

    2011-10-06

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  19. Accelerating global forest mortality

    NASA Astrophysics Data System (ADS)

    McDowell, N. G.

    2014-12-01

    Forest mortality is apparently accelerating globally. The evidence supporting this contention is now substantial, as is the evidence suggesting the acceleration has just begun and will become progressively worse in upcoming decades. I will review the data and models used to make these contentions.

  20. Accelerators (3/5)

    ScienceCinema

    None

    2011-10-06

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  1. Peak-valley-peak pattern of histone modifications delineates active regulatory elements and their directionality.

    PubMed

    Pundhir, Sachin; Bagger, Frederik O; Lauridsen, Felicia B; Rapin, Nicolas; Porse, Bo T

    2016-05-19

    Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show that NFRs predicted by H3K4me1 and me3 patterns are associated with active enhancers and promoters, respectively. Furthermore, asymmetry in the height of peaks flanking the central valley can predict the directionality of stable transcription at promoters. Using PARE on ChIP-seq histone modifications from four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate both the histone modification landscape and the transcriptional activities governed by active enhancers and promoters, and therefore can be used for their prediction. PARE is freely available at http://servers.binf.ku.dk/pare. PMID:27095194

  2. Peak-valley-peak pattern of histone modifications delineates active regulatory elements and their directionality

    PubMed Central

    Pundhir, Sachin; Bagger, Frederik O.; Lauridsen, Felicia B.; Rapin, Nicolas; Porse, Bo T.

    2016-01-01

    Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show that NFRs predicted by H3K4me1 and me3 patterns are associated with active enhancers and promoters, respectively. Furthermore, asymmetry in the height of peaks flanking the central valley can predict the directionality of stable transcription at promoters. Using PARE on ChIP-seq histone modifications from four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate both the histone modification landscape and the transcriptional activities governed by active enhancers and promoters, and therefore can be used for their prediction. PARE is freely available at http://servers.binf.ku.dk/pare. PMID:27095194

  3. The accuracy of portable peak flow meters.

    PubMed Central

    Miller, M R; Dickinson, S A; Hitchings, D J

    1992-01-01

    BACKGROUND: The variability of peak expiratory flow (PEF) is now commonly used in the diagnosis and management of asthma. It is essential for PEF meters to have a linear response in order to obtain an unbiased measurement of PEF variability. As the accuracy and linearity of portable PEF meters have not been rigorously tested in recent years this aspect of their performance has been investigated. METHODS: The response of several portable PEF meters was tested with absolute standards of flow generated by a computer driven, servo controlled pump and their response was compared with that of a pneumotachograph. RESULTS: For each device tested the readings were highly repeatable to within the limits of accuracy with which the pointer position can be assessed by eye. The between instrument variation in reading for six identical devices expressed as a 95% confidence limit was, on average across the range of flows, +/- 8.5 l/min for the Mini-Wright, +/- 7.9 l/min for the Vitalograph, and +/- 6.4 l/min for the Ferraris. PEF meters based on the Wright meter all had similar error profiles with overreading of up to 80 l/min in the mid flow range from 300 to 500 l/min. This overreading was greatest for the Mini-Wright and Ferraris devices, and less so for the original Wright and Vitalograph meters. A Micro-Medical Turbine meter was accurate up to 400 l/min and then began to underread by up to 60 l/min at 720 l/min. For the low range devices the Vitalograph device was accurate to within 10 l/min up to 200 l/min, with the Mini-Wright overreading by up to 30 l/min above 150 l/min. CONCLUSION: Although the Mini-Wright, Ferraris, and Vitalograph meters gave remarkably repeatable results their error profiles for the full range meters will lead to important errors in recording PEF variability. This may lead to incorrect diagnosis and bias in implementing strategies of asthma treatment based on PEF measurement. PMID:1465746

  4. Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams

    SciTech Connect

    Siemann, R.H.; /SLAC

    2011-10-24

    Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

  5. Cascaded radiation pressure acceleration

    SciTech Connect

    Pei, Zhikun; Shen, Baifei E-mail: zhxm@siom.ac.cn; Zhang, Xiaomei E-mail: zhxm@siom.ac.cn; Wang, Wenpeng; Zhang, Lingang; Yi, Longqing; Shi, Yin; Xu, Zhizhan

    2015-07-15

    A cascaded radiation-pressure acceleration scheme is proposed. When an energetic proton beam is injected into an electrostatic field moving at light speed in a foil accelerated by light pressure, protons can be re-accelerated to much higher energy. An initial 3-GeV proton beam can be re-accelerated to 7 GeV while its energy spread is narrowed significantly, indicating a 4-GeV energy gain for one acceleration stage, as shown in one-dimensional simulations and analytical results. The validity of the method is further confirmed by two-dimensional simulations. This scheme provides a way to scale proton energy at the GeV level linearly with laser energy and is promising to obtain proton bunches at tens of gigaelectron-volts.

  6. FAST CONTRACTION OF CORONAL LOOPS AT THE FLARE PEAK

    SciTech Connect

    Liu Rui; Wang Haimin

    2010-05-01

    On 2005 September 8, a coronal loop overlying the active region NOAA 10808 was observed in TRACE 171 A to contract at {approx}100 km s{sup -1} at the peak of an X5.4-2B flare at 21:05 UT. Prior to the fast contraction, the loop underwent a much slower contraction at {approx}6 km s{sup -1} for about 8 minutes, initiating during the flare preheating phase. The sudden switch to fast contraction is presumably corresponding to the onset of the impulsive phase. The contraction resulted in the oscillation of a group of loops located below, with the period of about 10 minutes. Meanwhile, the contracting loop exhibited a similar oscillatory pattern superimposed on the dominant downward motion. We suggest that the fast contraction reflects a suddenly reduced magnetic pressure underneath due either to (1) the eruption of magnetic structures located at lower altitudes or to (2) the rapid conversion of magnetic free energy in the flare core region. Electrons accelerated in the shrinking trap formed by the contracting loop can theoretically contribute to a late-phase hard X-ray burst, which is associated with Type IV radio emission. To complement the X5.4 flare which was probably confined, a similar event observed in SOHO/EIT 195 A on 2004 July 20 in an eruptive, M8.6 flare is briefly described, in which the contraction was followed by the expansion of the same loop leading up to a halo coronal mass ejection. These observations further substantiate the conjecture of coronal implosion and suggest coronal implosion as a new exciter mechanism for coronal loop oscillations.

  7. Agreement between vertical ground reaction force and ground reaction force vector in five common clinical tests.

    PubMed

    Veilleux, L N; Rauch, F; Lemay, M; Ballaz, L

    2012-12-01

    Mechanography is an innovative method to evaluate lower-limb dynamic muscle function. This technique is generally performed on force platforms that measure only the vertical component of ground reaction force (GRF). The underlying assumption is that medio-lateral and antero-posterior forces do not contribute significantly to the GRF in jumping and rising tests. The goal of this study was to establish the validity of this assumption. Fifteen healthy adults (mean age [SD]: 30 [11] years; mean height [SD]: 1.68 [0.12] m; mean body mass: 70 [18] kg) performed three repetitions of five different tests in the following order: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, heel-rise test and chair-rise test. An excellent agreement was found between peak GRF and peak vertical GRF. In each of the five tests, peak vertical GRF represented more than 99% of peak GRF. Moreover, the limits of agreement ranged between 0.05% (multiple two-legged hopping test) and 0.4% (heel-rise test) of the averaged peak force measurements. Therefore measuring only the vertical component of ground reaction force in healthy participants is appropriate for the five tests used in the present study. PMID:23196264

  8. Experimental validation of the dual positive and negative ion beam acceleration in the plasma propulsion with electronegative gases thruster

    SciTech Connect

    Rafalskyi, Dmytro Popelier, Lara; Aanesland, Ane

    2014-02-07

    The PEGASES (Plasma Propulsion with Electronegative Gases) thruster is a gridded ion thruster, where both positive and negative ions are accelerated to generate thrust. In this way, additional downstream neutralization by electrons is redundant. To achieve this, the thruster accelerates alternately positive and negative ions from an ion-ion plasma where the electron density is three orders of magnitude lower than the ion densities. This paper presents a first experimental study of the alternate acceleration in PEGASES, where SF{sub 6} is used as the working gas. Various electrostatic probes are used to investigate the source plasma potential and the energy, composition, and current of the extracted beams. We show here that the plasma potential control in such system is key parameter defining success of ion extraction and is sensitive to both parasitic electron current paths in the source region and deposition of sulphur containing dielectric films on the grids. In addition, large oscillations in the ion-ion plasma potential are found in the negative ion extraction phase. The oscillation occurs when the primary plasma approaches the grounded parts of the main core via sub-millimetres technological inputs. By controlling and suppressing the various undesired effects, we achieve perfect ion-ion plasma potential control with stable oscillation-free operation in the range of the available acceleration voltages (±350 V). The measured positive and negative ion currents in the beam are about 10 mA for each component at RF power of 100 W and non-optimized extraction system. Two different energy analyzers with and without magnetic electron suppression system are used to measure and compare the negative and positive ion and electron fluxes formed by the thruster. It is found that at alternate ion-ion extraction the positive and negative ion energy peaks are similar in areas and symmetrical in position with +/− ion energy corresponding to the amplitude of the applied

  9. Combining hypoxic methods for peak performance.

    PubMed

    Millet, Gregoire P; Roels, B; Schmitt, L; Woorons, X; Richalet, J P

    2010-01-01

    New methods and devices for pursuing performance enhancement through altitude training were developed in Scandinavia and the USA in the early 1990s. At present, several forms of hypoxic training and/or altitude exposure exist: traditional 'live high-train high' (LHTH), contemporary 'live high-train low' (LHTL), intermittent hypoxic exposure during rest (IHE) and intermittent hypoxic exposure during continuous session (IHT). Although substantial differences exist between these methods of hypoxic training and/or exposure, all have the same goal: to induce an improvement in athletic performance at sea level. They are also used for preparation for competition at altitude and/or for the acclimatization of mountaineers. The underlying mechanisms behind the effects of hypoxic training are widely debated. Although the popular view is that altitude training may lead to an increase in haematological capacity, this may not be the main, or the only, factor involved in the improvement of performance. Other central (such as ventilatory, haemodynamic or neural adaptation) or peripheral (such as muscle buffering capacity or economy) factors play an important role. LHTL was shown to be an efficient method. The optimal altitude for living high has been defined as being 2200-2500 m to provide an optimal erythropoietic effect and up to 3100 m for non-haematological parameters. The optimal duration at altitude appears to be 4 weeks for inducing accelerated erythropoiesis whereas <3 weeks (i.e. 18 days) are long enough for beneficial changes in economy, muscle buffering capacity, the hypoxic ventilatory response or Na(+)/K(+)-ATPase activity. One critical point is the daily dose of altitude. A natural altitude of 2500 m for 20-22 h/day (in fact, travelling down to the valley only for training) appears sufficient to increase erythropoiesis and improve sea-level performance. 'Longer is better' as regards haematological changes since additional benefits have been shown as hypoxic exposure

  10. Ground characterization for JAPE

    NASA Technical Reports Server (NTRS)

    Attenborough, Keith; Taherzadeh, Shahram

    1993-01-01

    Above-ground propagation modelling at the JAPE (Joint Acoustic Propagation Experiment) site requires a reasonably accurate model for the acoustical properties of the ground. Various models for the JAPE site are offered based on theoretical fits to short range data and to longer range data obtained with random noise and pure tones respectively from a loudspeaker under approximately quiescent isothermal conditions.

  11. LASRE ground hotfire #2

    NASA Technical Reports Server (NTRS)

    1997-01-01

    operation characteristics. The first of these flights occurred March 4, 1998. The SR-71 took off at 10:16 a.m. PST. The aircraft flew for one hour and fifty-seven minutes, reaching a maximum speed of Mach 1.58 before landing at Edwards, California, at 12:13 p.m. PST. During further flights in the spring and summer of 1998, liquid oxygen was cycled through the engine. In addition, two engine hot firings were conducted on the ground. It was decided not to do a final hot-fire flight test as a result of the liquid oxygen leaks in the test apparatus. The ground firings and the airborne cryogenic gas flow tests provided enough information to predict the hot gas effects of an aerospike engine firing during flight. The experiment itself was a small, half-span model that contained eight thrust cells of an aerospike engine and was mounted on a housing known as the 'canoe,' which contained the gaseous hydrogen, helium and instrumentation. The model, engine and canoe together were called the 'pod.' The entire pod was 41 feet in length and weighed 14,300 pounds. The experimental pod was mounted on NASA's SR-71, on loan to NASA from the U.S. Air Force. Lockheed Martin may use information gained from LASRE and the X-33 Advanced Technology Demonstrator to develop a potential future reusable launch vehicle. NASA and Lockheed Martin are partners in the X-33 program through a cooperative agreement.The goal of the X-33 program, and a major goal for NASA's Office of Aero-Space Technology, has been to enable significant reductions in the cost of access to space, and to promote the creation and delivery of new space services and other activities that will improve U.S. economic competitiveness. The program implements the National Space Transportation Policy, which was designed to accelerate the development of new launch technologies and concepts that contribute to the continuing commercialization of the national space launch industry. Both the flagship X-33 and the smaller X-34 technology testbed

  12. Quiet Spike Build-Up Ground Vibration Testing Approach

    NASA Technical Reports Server (NTRS)

    Spivey, Natalie D.; Herrera, Claudia Y.; Truax, Roger; Pak, Chan-gi; Freund, Donald

    2007-01-01

    NASA's Dryden Flight Research Center uses a modified F-15B (836) aircraft as a testbed for a variety of flight research:experiments mounted underneath the aircraft fuselage. The F-15B was selected to fly Gulfstream Aerospace Corporation's (GAC)QuietSpike(TM)(QS) project; however, this experiment is very unique and unlike any of the previous testbed experiments flown on the F-15B. It involves the addition of a relatively long quiet spike boom attached to the radar bulkhead of the aircraft. This QS experiment is a stepping stone to airframe structural morphing technologies designed to mitigate sonic born strength of business jets over land. The QS boom is a concept in Which an aircraft's front-end would be extended prior to supersonic acceleration. This morphing would effectively lengthen the aircraft, reducing peak sonic boom amplitude, but is also expected to partition the otherwise strong bow shock into a series of reduced-strength, non-coalescing shocklets. Prior to flying the Quietspike(TM) experiment on the F-15B aircraft several ground vibration tests (GVT) were required in order to understand the QS modal characteristics and coupling effects with the F-15B. However, due to the project's late hardware delivery of the QS and the intense schedule, a "traditional" GVT of the mated F-1513 Quietspike(tm) ready-for-flight configuration would not have left sufficient time available for the finite element model update and flutter analyses before flight testing. Therefore, a "nontraditional" ground vibration testing approach was taken. The objective of the QuietSpike (TM) build-up ground testing approach was to ultimately obtain confidence in the F-15B Quietspike(TM) finite element model (FEM) to be used for the flutter analysis. In order to obtain the F15B QS FEM with reliable foundation stiffness between the QS and the F-15B radar bulkhead as well as QS modal characteristics, several different GVT configurations were performed. EAch of the four GVT's performed had a

  13. Efficient Optical Energy Harvesting in Self-Accelerating Beams

    PubMed Central

    Bongiovanni, Domenico; Hu, Yi; Wetzel, Benjamin; Robles, Raul A.; Mendoza González, Gregorio; Marti-Panameño, Erwin A.; Chen, Zhigang; Morandotti, Roberto

    2015-01-01

    We report the experimental observation of energetically confined self-accelerating optical beams propagating along various convex trajectories. We show that, under an appropriate transverse compression of their spatial spectra, these self-accelerating beams can exhibit a dramatic enhancement of their peak intensity and a significant decrease of their transverse expansion, yet retaining both the expected acceleration profile and the intrinsic self-healing properties. We found our experimental results to be in excellent agreement with the numerical simulations. We expect further applications in such contexts where power budget and optimal spatial confinement can be important limiting factors. PMID:26299360

  14. Efficient Optical Energy Harvesting in Self-Accelerating Beams

    NASA Astrophysics Data System (ADS)

    Bongiovanni, Domenico; Hu, Yi; Wetzel, Benjamin; Robles, Raul A.; Mendoza González, Gregorio; Marti-Panameño, Erwin A.; Chen, Zhigang; Morandotti, Roberto

    2015-08-01

    We report the experimental observation of energetically confined self-accelerating optical beams propagating along various convex trajectories. We show that, under an appropriate transverse compression of their spatial spectra, these self-accelerating beams can exhibit a dramatic enhancement of their peak intensity and a significant decrease of their transverse expansion, yet retaining both the expected acceleration profile and the intrinsic self-healing properties. We found our experimental results to be in excellent agreement with the numerical simulations. We expect further applications in such contexts where power budget and optimal spatial confinement can be important limiting factors.

  15. Ground energy coupling

    NASA Astrophysics Data System (ADS)

    Metz, P. D.

    The feasibility of ground coupling for various heat pump systems was investigated. Analytical heat flow models were developed to approximate design ground coupling devices for use in solar heat pump space conditioning systems. A digital computer program called GROCS (GRound Coupled Systems) was written to model 3-dimensional underground heat flow in order to simulate the behavior of ground coupling experiments and to provide performance predictions which have been compared to experimental results. GROCS also has been integrated with TRNSYS. Soil thermal property and ground coupling device experiments are described. Buried tanks, serpentine earth coils in various configurations, lengths and depths, and sealed vertical wells are being investigated. An earth coil used to heat a house without use of resistance heating is described.

  16. 7 CFR 457.163 - Nursery peak inventory endorsement.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... completed Peak Inventory Value Report is received by us. Coverage term. A period of time that begins on the... otherwise modify any other provision of your Nursery Crop Insurance Policy. 4. Peak Insurance Period... 7 Agriculture 6 2014-01-01 2014-01-01 false Nursery peak inventory endorsement. 457.163...

  17. 7 CFR 457.163 - Nursery peak inventory endorsement.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... completed Peak Inventory Value Report is received by us. Coverage term. A period of time that begins on the... otherwise modify any other provision of your Nursery Crop Insurance Policy. 4. Peak Insurance Period... 7 Agriculture 6 2012-01-01 2012-01-01 false Nursery peak inventory endorsement. 457.163...

  18. 7 CFR 457.163 - Nursery peak inventory endorsement.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... completed Peak Inventory Value Report is received by us. Coverage term. A period of time that begins on the... otherwise modify any other provision of your Nursery Crop Insurance Policy. 4. Peak Insurance Period... 7 Agriculture 6 2011-01-01 2011-01-01 false Nursery peak inventory endorsement. 457.163...

  19. Peak Shift Phenomenon: A Teaching Activity for Basic Learning Theory

    ERIC Educational Resources Information Center

    Keith, Kenneth D.

    2002-01-01

    Stimulus discrimination is a standard subject in undergraduate courses presenting basic principles of learning, and a particularly interesting aspect of discrimination is the peak shift phenomenon. Peak shift occurs in generalization tests following intradimensional discrimination training as a displacement of peak responding away from the S+ (a…

  20. Reward Value Effects on Timing in the Peak Procedure

    ERIC Educational Resources Information Center

    Galtress, Tiffany; Kirkpatrick, Kimberly

    2009-01-01

    Three experiments examined the effect of motivational variables on timing in the peak procedure. In Experiment 1, rats received a 60-s peak procedure that was coupled with long-term, between-phase changes in reinforcer magnitude. Increases in reinforcer magnitude produced a leftward shift in the peak that persisted for 20 sessions of training. In…