Time dependent heat transfer rates in high Reynolds number hypersonic flowfields

NASA Technical Reports Server (NTRS)

Flanagan, Michael J.

1992-01-01

Time dependent heat transfer rates have been calculated from time dependent temperature measurements in the vicinity of shock-wave boundary-layer interactions due to conical compression ramps on an axisymmetric body. The basic model is a cylindrical body with a 10 degree conical nose. Four conical ramps, 20, 25, 30, and 35 degrees serve as shock wave generators. Flowfield surveys have been made in the vicinity of the conical ramp vertex, the separation point, and the reattachment point. A significant effort was made to characterize the natural frequencies and relative powers of the resulting fluctuations in heat transfer rates. This research effort, sponsored jointly by NASA and the Air Force, was conducted in the Air Force Flight Dynamics Directorate High Reynolds Facility. The nominal freestream Mach number was 6, and the freestream Reynolds numbers ranged from 2.2 million/ft to 30.0 million/ft. Experimental results quantify temperature response and the resulting heat transfer rates as a function of ramp angle and Reynolds number. The temperature response within the flowfield appears to be steady-state for all compression ramp angles and all Reynolds numbers, and hence, the heat transfer rates appear to be steady-state.

Time dependent heat transfer rates in high Reynolds number hypersonic flowfields

NASA Astrophysics Data System (ADS)

Flanagan, Michael J.

1992-09-01

Time dependent heat transfer rates have been calculated from time dependent temperature measurements in the vicinity of shock-wave boundary-layer interactions due to conical compression ramps on an axisymmetric body. The basic model is a cylindrical body with a 10 degree conical nose. Four conical ramps, 20, 25, 30, and 35 degrees serve as shock wave generators. Flowfield surveys have been made in the vicinity of the conical ramp vertex, the separation point, and the reattachment point. A significant effort was made to characterize the natural frequencies and relative powers of the resulting fluctuations in heat transfer rates. This research effort, sponsored jointly by NASA and the Air Force, was conducted in the Air Force Flight Dynamics Directorate High Reynolds Facility. The nominal freestream Mach number was 6, and the freestream Reynolds numbers ranged from 2.2 million/ft to 30.0 million/ft. Experimental results quantify temperature response and the resulting heat transfer rates as a function of ramp angle and Reynolds number. The temperature response within the flowfield appears to be steady-state for all compression ramp angles and all Reynolds numbers, and hence, the heat transfer rates appear to be steady-state.

Testing the effects of topography, geometry, and kinematics on modeled thermochronometer cooling ages in the eastern Bhutan Himalaya

NASA Astrophysics Data System (ADS)

Gilmore, Michelle E.; McQuarrie, Nadine; Eizenhöfer, Paul R.; Ehlers, Todd A.

2018-05-01

In this study, reconstructions of a balanced geologic cross section in the Himalayan fold-thrust belt of eastern Bhutan are used in flexural-kinematic and thermokinematic models to understand the sensitivity of predicted cooling ages to changes in fault kinematics, geometry, topography, and radiogenic heat production. The kinematics for each scenario are created by sequentially deforming the cross section with ˜ 10 km deformation steps while applying flexural loading and erosional unloading at each step to develop a high-resolution evolution of deformation, erosion, and burial over time. By assigning ages to each increment of displacement, we create a suite of modeled scenarios that are input into a 2-D thermokinematic model to predict cooling ages. Comparison of model-predicted cooling ages to published thermochronometer data reveals that cooling ages are most sensitive to (1) the location and size of fault ramps, (2) the variable shortening rates between 68 and 6.4 mm yr-1, and (3) the timing and magnitude of out-of-sequence faulting. The predicted ages are less sensitive to (4) radiogenic heat production and (5) estimates of topographic evolution. We used the observed misfit of predicted to measured cooling ages to revise the cross section geometry and separate one large ramp previously proposed for the modern décollement into two smaller ramps. The revised geometry results in an improved fit to observed ages, particularly young AFT ages (2-6 Ma) located north of the Main Central Thrust. This study presents a successful approach for using thermochronometer data to test the viability of a proposed cross section geometry and kinematics and describes a viable approach to estimating the first-order topographic evolution of a compressional orogen.

Effect of ramp configuration on easiness of handling, heart rate, and behavior of near-market weight pigs at unloading.

PubMed

Goumon, S; Faucitano, L; Bergeron, R; Crowe, T; Connor, M L; Gonyou, H W

2013-08-01

Three experiments, each using 280 pigs, were conducted in a simulated compartment to test the effect of angle of entrance (AOE) to the ramp (90°, 60°, 30°, or 0°), ramp slope (0°, 16°, 21°, or 26°), and an initial 20-cm step associated with 16° or 21° ramp slopes on the ease of handling, heart rate (HR), and behavior of near market-weight pigs during unloading. Heart rate (pigs and handler), unloading time, interventions of the handler, and reactions of the pigs were monitored. The results of the first experiment show that using a 90° AOE had detrimental effects on ease of handling (P < 0.05), HR of the pig (P < 0.05), and behavior (P < 0.05). The 0° and 30° AOE appeared to improve the ease of unloading, whereas the 60° AOE had an intermediate effect. The 30° AOE appeared to be preferable, because pigs moved at this angle balked less frequently (P < 0.01) and required less manipulation (P < 0.05) than pigs moved with a 0° AOE. The results of the second experiment show that the use of a flat ramp led to the easiest unloading, as demonstrated by the lower number of balks (P < 0.001) when pigs were moved to the ramp and less frequent use of paddle (P = 0.001) or voice (P < 0.001) on the ramp, compared with the other treatments. However, the flat ramp did not differ from the 21° ramp in many of the variables reflecting ease of handling, which may be explained by the difference in configuration between the ramps. The results also show that the use of the steepest ramp slope had the most detrimental effect on balking and backing up behavior of pigs (P < 0.001), and handling (touches, slaps, and pushes; P < 0.05 for all) when moved to the ramp and on unloading time (P < 0.01). No differences in pig HR (P < 0.05) and ease of handling on the ramp (P < 0.05) were found between a 26° and 16° ramp slope, suggesting that the length of the ramp may be one of the factors that make unloading more difficult. The results of the last experiment show that an initial step made unloading physically more demanding for the handler (P < 0.001) and pigs on the ramp (P < 0.05) as demonstrated by their greater HR. The greater difficulty of handling (P < 0.01) and reluctance to move (P < 0.05) of pigs moved toward the 16° ramp with a step suggest that pigs perceived this ramp as more psychologically challenging. Making a few changes in terms of the design of the ramp could improve the efficiency of handling and reduce stress in pigs.

Integrated database and analysis system for the evaluation of freeway corridors for potential ramp signaling.

DOT National Transportation Integrated Search

2011-11-15

Ramp signaling is a relatively low-cost traffic management strategy that aims to improve the flow of : traffic by controlling the rate at which vehicles enter the freeway. While studies have shown that ramp : signaling helps to alleviate traffic cong...

Interaction of rate- and size-effect using a dislocation density based strain gradient viscoplasticity model

NASA Astrophysics Data System (ADS)

Nguyen, Trung N.; Siegmund, Thomas; Tomar, Vikas; Kruzic, Jamie J.

2017-12-01

Size effects occur in non-uniform plastically deformed metals confined in a volume on the scale of micrometer or sub-micrometer. Such problems have been well studied using strain gradient rate-independent plasticity theories. Yet, plasticity theories describing the time-dependent behavior of metals in the presence of size effects are presently limited, and there is no consensus about how the size effects vary with strain rates or whether there is an interaction between them. This paper introduces a constitutive model which enables the analysis of complex load scenarios, including loading rate sensitivity, creep, relaxation and interactions thereof under the consideration of plastic strain gradient effects. A strain gradient viscoplasticity constitutive model based on the Kocks-Mecking theory of dislocation evolution, namely the strain gradient Kocks-Mecking (SG-KM) model, is established and allows one to capture both rate and size effects, and their interaction. A formulation of the model in the finite element analysis framework is derived. Numerical examples are presented. In a special virtual creep test with the presence of plastic strain gradients, creep rates are found to diminish with the specimen size, and are also found to depend on the loading rate in an initial ramp loading step. Stress relaxation in a solid medium containing cylindrical microvoids is predicted to increase with decreasing void radius and strain rate in a prior ramp loading step.

Development of criteria and guidelines for installing, operating, and removing TxDOT ramp control signals.

DOT National Transportation Integrated Search

2009-05-01

The Texas Department of Transportation (TxDOT) uses ramp control signals (also called ramp meters or : flow signals) to control the rate at which vehicles enter the freeway. This helps TxDOT (1) promote a more : consistent and uniform flow of traffic...

Traffic dynamics of an on-ramp system with a cellular automaton model

NASA Astrophysics Data System (ADS)

Li, Xin-Gang; Gao, Zi-You; Jia, Bin; Jiang, Rui

2010-06-01

This paper uses the cellular automaton model to study the dynamics of traffic flow around an on-ramp with an acceleration lane. It adopts a parameter, which can reflect different lane-changing behaviour, to represent the diversity of driving behaviour. The refined cellular automaton model is used to describe the lower acceleration rate of a vehicle. The phase diagram and the capacity of the on-ramp system are investigated. The simulation results show that in the single cell model, the capacity of the on-ramp system will stay at the highest flow of a one lane system when the driver is moderate and careful; it will be reduced when the driver is aggressive. In the refined cellular automaton model, the capacity is always reduced even when the driver is careful. It proposes that the capacity drop of the on-ramp system is caused by aggressive lane-changing behaviour and lower acceleration rate.

Effectiveness of a multidisciplinary risk assessment and management programme-diabetes mellitus (RAMP-DM) on patient-reported outcomes.

PubMed

Wan, Eric Yuk Fai; Fung, Colman Siu Cheung; Wong, Carlos King Ho; Choi, Edmond Pui Hang; Jiao, Fang Fang; Chan, Anca Ka Chun; Chan, Karina Hiu Yen; Lam, Cindy Lo Kuen

2017-02-01

Little is known about how the patient-reported outcomes is influenced by multidisciplinary-risk-assessment-and-management-programme for patients with diabetes mellitus (RAMP-DM). This paper aims to evaluate the effectiveness of RAMP-DM on patient-reported outcomes. This was a prospective longitudinal study on 1039 diabetes mellitus patients (714/325 RAMP-DM/non-RAMP-DM) managed in primary care setting. 536 and 402 RAMP-DM participants, and 237 and 187 non-RAMP-DM participants were followed up at 12 and 24 months with completed survey, respectively. Patient-reported outcomes included health-related quality of life, change in global health condition and patient enablement measured by Short Form-12 Health Survey version-2 (SF-12v2), Global Rating Scale, Patient Enablement Instrument respectively. The effects of RAMP-DM on patient-reported outcomes were evaluated by mixed effect models. Subgroup analysis was performed by stratifying haemoglobin A1c (HbA1c) (optimal HbA1c < 7 % and suboptimal HbA1c ≥ 7 %). RAMP-DM with suboptimal HbA1c was associated with greater improvement in SF-12v2 physical component summary score at 12-month (coefficient:3.80; P-value < 0.05) and 24-month (coefficient:3.82;P-value < 0.05), more likely to feel more enabled at 12-month (odds ratio: 2.57; P-value < 0.05), and have improved in GRS at 24-month (odds ratio:4.05; P-value < 0.05) compared to non-RAMP-DM participants. However, there was no significant difference in patient-reported outcomes between RAMP-DM and non-RAMP-DM participants with optimal HbA1c. Participation in RAMP-DM is effective in improving physical component of HRQOL, Global Rating Scale and patient enablement among diabetes mellitus patients with suboptimal HbA1c, but not in those with optimal HbA1c. Patients with sub-optimal diabetes mellitus control should be the priority target population for RAMP-DM. This observational study design may have potential bias in the characteristics between groups, and randomized clinical trial is needed to confirm the results.

Mechanisms of High-Temperature Fatigue Failure in Alloy 800H

NASA Technical Reports Server (NTRS)

BhanuSankaraRao, K.; Schuster, H.; Halford, G. R.

1996-01-01

The damage mechanisms influencing the axial strain-controlled Low-Cycle Fatigue (LCF) behavior of alloy 800H at 850 C have been evaluated under conditions of equal tension/compression ramp rates (Fast-Fast (F-F): 4 X 10(sup -3)/s and Slow-Slow (S-S): 4 X 10(sup -5)/s) and asymmetrical ramp rates (Fast-Slow (F-S): 4 x 10(sup -3)/s / 4 X 10(sup -5/s and Slow-Fast (S-F): 4 X 10(sup -5) / 4 X 10(sup -3)/s) in tension and compression. The fatigue life, cyclic stress response, and fracture modes were significantly influenced by the waveform shape. The fatigue lives displayed by different loading conditions were in the following order: F-F greater than S-S greater than F-S greater than S-F. The fracture mode was dictated by the ramp rate adopted in the tensile direction. The fast ramp rate in the tensile direction led to the occurrence of transgranular crack initiation and propagation, whereas the slow ramp rate caused intergranular initiation and propagation. The time-dependent processes and their synergistic interactions, which were at the basis of observed changes in cyclic stress response and fatigue life, were identified. Oxidation, creep damage, dynamic strain aging, massive carbide precipitation, time-dependent creep deformation, and deformation ratcheting were among the several factors influencing cyclic life. Irrespective of the loading condition, the largest effect on life was exerted by oxidation processes. Deformation ratcheting had its greatest influence on life under asymmetrical loading conditions. Creep damage accumulated the greatest amount during the slow tensile ramp under S-F conditions.

Constant gradient PFG sequence and automated cumulant analysis for quantifying dispersion in flow through porous media.

PubMed

Scheven, U M

2013-12-01

This paper describes a new variant of established stimulated echo pulse sequences, and an analytical method for determining diffusion or dispersion coefficients for Gaussian or non-Gaussian displacement distributions. The unipolar displacement encoding PFGSTE sequence uses trapezoidal gradient pulses of equal amplitude g and equal ramp rates throughout while sampling positive and negative halves of q-space. Usefully, the equal gradient amplitudes and gradient ramp rates help to reduce the impact of experimental artefacts caused by residual amplifier transients, eddy currents, or ferromagnetic hysteresis in components of the NMR magnet. The pulse sequence was validated with measurements of diffusion in water and of dispersion in flow through a packing of spheres. The analytical method introduced here permits the robust determination of the variance of non-Gaussian, dispersive displacement distributions. The noise sensitivity of the analytical method is shown to be negligible, using a demonstration experiment with a non-Gaussian longitudinal displacement distribution, measured on flow through a packing of mono-sized spheres. Copyright © 2013 Elsevier Inc. All rights reserved.

Power ramp rate capabilities of a 5 kW proton exchange membrane fuel cell system with discrete ejector control

NASA Astrophysics Data System (ADS)

Nikiforow, K.; Pennanen, J.; Ihonen, J.; Uski, S.; Koski, P.

2018-03-01

The power ramp rate capabilities of a 5 kW proton exchange membrane fuel cell (PEMFC) system are studied theoretically and experimentally for grid support service applications. The fuel supply is implemented with a fixed-geometry ejector and a discrete control solution without any anode-side pressure fluctuation suppression methods. We show that the stack power can be ramped up from 2.0 kW to 4.0 kW with adequate fuel supply and low anode pressure fluctuations within only 0.1 s. The air supply is implemented with a centrifugal blower. Air supply ramp rates are studied with a power increase executed within 1 and 0.2 s after the request, the time dictated by grid support service requirements in Finland and the UK. We show that a power ramp-up from 2.0 kW to 3.7 kW is achieved within 1 s with an initial air stoichiometry of 2.5 and within 0.2 s with an initial air stoichiometry of 7.0. We also show that the timing of the power ramp-up affects the achieved ancillary power capacity. This work demonstrates that hydrogen fueled and ejector-based PEMFC systems can provide a significant amount of power in less than 1 s and provide valuable ancillary power capacity for grid support services.

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

Rosenkranz, Joshua-Benedict; Brancucci Martinez-Anido, Carlo; Hodge, Bri-Mathias

Solar power generation, unlike conventional forms of electricity generation, has higher variability and uncertainty in its output because solar plant output is strongly impacted by weather. As the penetration rate of solar capacity increases, grid operators are increasingly concerned about accommodating the increased variability and uncertainty that solar power provides. This paper illustrates the impacts of increasing solar power penetration on the ramping of conventional electricity generators by simulating the operation of the Independent System Operator -- New England power system. A production cost model was used to simulate the power system under five different scenarios, one without solar powermore » and four with increasing solar power penetrations up to 18%, in terms of annual energy. The impact of solar power is analyzed on six different temporal intervals, including hourly and multi-hourly (2- to 6-hour) ramping. The results show how the integration of solar power increases the 1- to 6-hour ramping events of the net load (electric load minus solar power). The study also analyzes the impact of solar power on the distribution of multi-hourly ramping events of fossil-fueled generators and shows increasing 1- to 6-hour ramping events for all different generators. Generators with higher ramp rates such as gas and oil turbine and internal combustion engine generators increased their ramping events by 200% to 280%. For other generator types--including gas combined-cycle generators, coal steam turbine generators, and gas and oil steam turbine generators--more and higher ramping events occurred as well for higher solar power penetration levels.« less

Modeling rate sensitivity of exercise transient responses to limb motion.

PubMed

Yamashiro, Stanley M; Kato, Takahide

2014-10-01

Transient responses of ventilation (V̇e) to limb motion can exhibit predictive characteristics. In response to a change in limb motion, a rapid change in V̇e is commonly observed with characteristics different than during a change in workload. This rapid change has been attributed to a feed-forward or adaptive response. Rate sensitivity was explored as a specific hypothesis to explain predictive V̇e responses to limb motion. A simple model assuming an additive feed-forward summation of V̇e proportional to the rate of change of limb motion was studied. This model was able to successfully account for the adaptive phase correction observed during human sinusoidal changes in limb motion. Adaptation of rate sensitivity might also explain the reduction of the fast component of V̇e responses previously reported following sudden exercise termination. Adaptation of the fast component of V̇e response could occur by reduction of rate sensitivity. Rate sensitivity of limb motion was predicted by the model to reduce the phase delay between limb motion and V̇e response without changing the steady-state response to exercise load. In this way, V̇e can respond more quickly to an exercise change without interfering with overall feedback control. The asymmetry between responses to an incremental and decremental ramp change in exercise can also be accounted for by the proposed model. Rate sensitivity leads to predicted behavior, which resembles responses observed in exercise tied to expiratory reserve volume. Copyright © 2014 the American Physiological Society.

The microprocessor-based synthesizer controller

NASA Technical Reports Server (NTRS)

Wick, M. R.

1980-01-01

Implementation and performance of the microprocessor-based controllers and Dana Digiphase Synthesizer (DCO) installed in the Deep Space Network exciter in the 64-meter and 34-meter subnets to support uplink tuning required for the Voyager-Saturn Encounter is discussed. Test data in tests conducted during the production of the controllers verified the design objective for phase control accuracy of 10 to the - 12 power cycles in eight hours during ramping. Tests conducted require a phase error between a theoretical calculated value and the actual phase of no greater than + or - 1 cycle. Tests included (1) a ramp over a period of eight hours using a ramp rate which covers the synthesizer tuning range (40-51 MHz) and (2) a ramp sequence using the maximum rate (+ or kHz/s) over the tuning range.

The Effects of Using a Ramp and Elevator to Load and Unload Trailers on the Behavior and Physiology of Piglets

PubMed Central

McGlone, John; Sapkota, Avi

2014-01-01

Simple Summary Transport is a routine practice in the modern swine industry. Loading the pigs into trailers can be a novel and stressful experience for the animals. This study compared behaviors and physiological variables during and after loading using a ramp or elevator to determine which method is the least stressful to the pigs. Loading pigs by ramp appears to cause more stress than loading by elevator. Abstract Transport is an inevitable process in the modern U.S. swine industry. The loading process is a novel and potentially stressful experience. This study uses behavior, heart rate and leukocyte counts to compare stress one hour before, during and after loading via ramp or elevator. Piglets were held in a home pen (control (CON)), walked up and down an aisle (handled (HAN)), or walked to a truck and loaded via elevator (ELE) or ramp (RAM). Sitting, feeding and blood parameters did not show a significant treatment by time effect (p > 0.05). Standing behavior did not differ between CON and HAN piglets nor between RAM and ELE piglets (p > 0.05); however, CON and HAN piglets stood more than RAM and ELE piglets during treatment (p < 0.05). After treatment, drinking behavior was increased in RAM piglets (p < 0.05). The heart rate of ELE piglets decreased 6.3% after treatment; whereas the heart rate of RAM piglets remained elevated 2.4% (p < 0.05). In terms of heart rate, loading by elevator appears to be less stressful than loading by ramp. PMID:26480323

Cortical activity associated with the perception of temporal asymmetry in ramped and damped noises.

PubMed

Rupp, André; Spachmann, André; Dettlaff, Anna; Patterson, Roy D

2013-01-01

Human listeners are very sensitive to the asymmetry of time-reversed pairs of ramped and damped sounds. When the carrier is noise, the hiss -component of the perception is stronger in ramped sounds and the drumming component is stronger in damped sounds (Akeroyd and Patterson 1995). In the current study, a paired comparison technique was used to establish the relative "hissiness" of these noises, and the ratings were correlated with (a) components of the auditory evoked field (AEF) produced by these noises and (b) the magnitude of a hissiness feature derived from a model of the internal auditory images produced by these noises (Irino and Patterson 1998). An earlier AEF report indicated that the peak magnitude of the transient N100m response mirrors the perceived salience of the tonal perception (Rupp et al. 2005). The AEFs of 14 subjects were recorded in response to damped/ramped noises with half-lives between 1 and 64 ms and repetition rates between 12.5 and 100 ms. Spatio-temporal source analysis was used to fit the P50m, the P200m, and the sustained field (SF). These noise stimuli did not produce a reliable N100m. The hissiness feature from the auditory model was extracted from a time-averaged sequence of summary auditory images as in Patterson and Irino (1998). The results show that the perceptual measure of hissiness is highly correlated with the hissiness feature from the summary auditory image, and both are highly correlated with the magnitude of the transient P200m. There is a significant but weaker correlation with the SF and a nonsignificant correlation with the P50m. The results suggest that regularity in the carrier effects branching at an early stage of auditory processing with tonal and noisy sounds following separate spatio-temporal routes through the system.

Orion Service Module Reaction Control System Plume Impingement Analysis Using PLIMP/RAMP2

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen J.; Gati, Frank; Yuko, James R.; Motil, Brian J.; Lumpkin, Forrest E.

2009-01-01

The Orion Crew Exploration Vehicle Service Module Reaction Control System engine plume impingement was computed using the plume impingement program (PLIMP). PLIMP uses the plume solution from RAMP2, which is the refined version of the reacting and multiphase program (RAMP) code. The heating rate and pressure (force and moment) on surfaces or components of the Service Module were computed. The RAMP2 solution of the flow field inside the engine and the plume was compared with those computed using GASP, a computational fluid dynamics code, showing reasonable agreement. The computed heating rate and pressure using PLIMP were compared with the Reaction Control System plume model (RPM) solution and the plume impingement dynamics (PIDYN) solution. RPM uses the GASP-based plume solution, whereas PIDYN uses the SCARF plume solution. Three sets of the heating rate and pressure solutions agree well. Further thermal analysis on the avionic ring of the Service Module showed that thermal protection is necessary because of significant heating from the plume.

Blood pressure regulation in neurally intact human vs. acutely injured paraplegic and tetraplegic patients during passive tilt.

PubMed

Aslan, Sevda C; Randall, David C; Donohue, Kevin D; Knapp, Charles F; Patwardhan, Abhijit R; McDowell, Susan M; Taylor, Robert F; Evans, Joyce M

2007-03-01

We investigated autonomic control of cardiovascular function in able-bodied (AB), paraplegic (PARA), and tetraplegic (TETRA) subjects in response to head-up tilt following spinal cord injury. We evaluated spectral power of blood pressure (BP), baroreflex sensitivity (BRS), baroreflex effectiveness index (BEI), occurrence of systolic blood pressure (SBP) ramps, baroreflex sequences, and cross-correlation of SBP with heart rate (HR) in low (0.04-0.15 Hz)- and high (0.15-0.4 Hz)-frequency regions. During tilt, AB and PARA effectively regulated BP and HR, but TETRA did not. The numbers of SBP ramps and percentages of heartbeats involved in SBP ramps and baroreflex sequences increased in AB, were unchanged in PARA, and declined in TETRA. BRS was lowest in PARA and declined with tilt in all groups. BEI was greatest in AB and declined with tilt in all groups. Low-frequency power of BP and the peak of the SBP/HR cross-correlation magnitude were greatest in AB, increased during tilt in AB, remained unchanged in PARA, and declined in TETRA. The peak cross-correlation magnitude in HF decreased with tilt in all groups. Our data indicate that spinal cord injury results in decreased stimulation of arterial baroreceptors and less engagement of feedback control as demonstrated by lower 1) spectral power of BP, 2) number (and percentages) of SBP ramps and barosequences, 3) cross-correlation magnitude of SBP/HR, 4) BEI, and 5) changes in delay between SBP/HR. Diminished vasomotion and impaired baroreflex regulation may be major contributors to decreased orthostatic tolerance following injury.

Laboratory Evaluation of Commercially Available Platforms to Detect West Nile and Zika Viruses From Honey Cards.

PubMed

Burkhalter, Kristen L; Wiggins, Keenan; Burkett-Cadena, Nathan; Alto, Barry W

2018-05-04

Commercially available assays utilizing antigen or nucleic acid detection chemistries provide options for mosquito control districts to screen their mosquito populations for arboviruses and make timely operational decisions regarding vector control. These assays may be utilized even more advantageously when combined with honey-soaked nucleic acid preservation substrate ('honey card') testing by reducing or replacing the time- and labor-intensive efforts of identifying and processing mosquito pools. We tested artificially inoculated honey cards and cards fed upon individually by West Nile virus (WNV) and Zika virus (ZIKV)-infected mosquitoes with three assays to compare detection rates and the limit of detection for each platform with respect to virus detection of a single infected mosquito and quantify the time interval of virus preservation on the cards. Assays evaluated included CDC protocols for real-time reverse transcriptase polymerase chain reaction (RT-PCR) for WNV and ZIKV, Pro-Lab Diagnostics ProAmpRT WNV loop-mediated amplification (LAMP) and ZIKV LAMP assays, and the Rapid Analyte Measurement Platform (RAMP) WNV assay. Real-time RT-PCR was the most sensitive assay and the most robust to viral RNA degradation over time. To maximize the detection of virus, honey cards should be left in the traps ≤1 d if using LAMP assays and ≤3 d if using real-time RT-PCR to detect viruses from field samples. The WNV RAMP assay, although effective for pool screening, lacks sensitivity required for honey card surveillance. Future studies may determine the minimum number of infectious mosquitoes required to feed on a honey card that would be reliably detected by the LAMP or RAMP assays.

Rate of warming affects temperature sensitivity of anaerobic peat decomposition and greenhouse gas production.

PubMed

Sihi, Debjani; Inglett, Patrick W; Gerber, Stefan; Inglett, Kanika S

2018-01-01

Temperature sensitivity of anaerobic carbon mineralization in wetlands remains poorly represented in most climate models and is especially unconstrained for warmer subtropical and tropical systems which account for a large proportion of global methane emissions. Several studies of experimental warming have documented thermal acclimation of soil respiration involving adjustments in microbial physiology or carbon use efficiency (CUE), with an initial decline in CUE with warming followed by a partial recovery in CUE at a later stage. The variable CUE implies that the rate of warming may impact microbial acclimation and the rate of carbon-dioxide (CO 2 ) and methane (CH 4 ) production. Here, we assessed the effects of warming rate on the decomposition of subtropical peats, by applying either a large single-step (10°C within a day) or a slow ramping (0.1°C/day for 100 days) temperature increase. The extent of thermal acclimation was tested by monitoring CO 2 and CH 4 production, CUE, and microbial biomass. Total gaseous C loss, CUE, and MBC were greater in the slow (ramp) warming treatment. However, greater values of CH 4 -C:CO 2 -C ratios lead to a greater global warming potential in the fast (step) warming treatment. The effect of gradual warming on decomposition was more pronounced in recalcitrant and nutrient-limited soils. Stable carbon isotopes of CH 4 and CO 2 further indicated the possibility of different carbon processing pathways under the contrasting warming rates. Different responses in fast vs. slow warming treatment combined with different endpoints may indicate alternate pathways with long-term consequences. Incorporations of experimental results into organic matter decomposition models suggest that parameter uncertainties in CUE and CH 4 -C:CO 2 -C ratios have a larger impact on long-term soil organic carbon and global warming potential than uncertainty in model structure, and shows that particular rates of warming are central to understand the response of wetland soils to global climate change. © 2017 John Wiley & Sons Ltd.

Heart Rate Variability as a Measure of Airport Ramp-Traffic Controllers Workload

NASA Technical Reports Server (NTRS)

Hayashi, Miwa; Dulchinos, Victoria Lee

2016-01-01

Heart Rate Variability (HRV) has been reported to reflect the person's cognitive and emotional stress levels, and may offer an objective measure of human-operator's workload levels, which are recorded continuously and unobtrusively to the task performance. The present paper compares the HRV data collected during a human-in-the-loop simulation of airport ramp-traffic control operations with the controller participants' own verbal self-reporting ratings of their workload.

The influence of heavy vehicles on traffic dynamics around on-ramp system: Cellular automata approach

NASA Astrophysics Data System (ADS)

Kong, Dewen; Guo, Xiucheng; Wu, Dingxin

Although the on-ramp system has been widely studied, the influence of heavy vehicles is unknown because researchers only investigate the traffic dynamics around on-ramp system under homogeneous traffic conditions, which is different in real-world settings. This paper uses an improved cellular automaton model to study the heterogeneous traffic around on-ramp system. The forward motion rules are improved by considering the differences of driving behavior in different vehicle combinations. The lane change rules are improved by reflecting the aggressive behavior in mandatory lane changes. The phase diagram, traffic flow, capacity and spatial-temporal diagram are analyzed under the influences of heavy vehicles. The results show that by increasing the percentage of heavy vehicles, there will be more severe traffic congestion around on-ramp system, lower saturated flow and capacity. Also, the interactions between main road and on-ramp have been investigated. Increasing the percentage of heavy vehicles at the upstream of the conflict area on the main road or restricting heavy vehicles on the outside lane of the main road will deteriorate the performance of on-ramp. While the main road will have better performance as the percentage of heavy vehicles on the on-ramp increases when the on-ramp inflow rate is not low.

Dynamic tensile fracture of mortar at ultra-high strain-rates

NASA Astrophysics Data System (ADS)

Erzar, B.; Buzaud, E.; Chanal, P.-Y.

2013-12-01

During the lifetime of a structure, concrete and mortar may be exposed to highly dynamic loadings, such as impact or explosion. The dynamic fracture at high loading rates needs to be well understood to allow an accurate modeling of this kind of event. In this work, a pulsed-power generator has been employed to conduct spalling tests on mortar samples at strain-rates ranging from 2 × 104 to 4 × 104 s-1. The ramp loading allowed identifying the strain-rate anytime during the test. A power law has been proposed to fit properly the rate-sensitivity of tensile strength of this cementitious material over a wide range of strain-rate. Moreover, a specimen has been recovered damaged but unbroken. Micro-computed tomography has been employed to study the characteristics of the damage pattern provoked by the dynamic tensile loading.

Simulation and experiment of thermal fatigue in the CPV die attach

NASA Astrophysics Data System (ADS)

Bosco, Nick; Silverman, Timothy; Kurtz, Sarah

2012-10-01

FEM simulation and accelerated thermal cycling have been performed for the CPV die attach. Trends in fatigue damage accumulation and equivalent test time are explored and found to be most sensitive to temperature ramp rate. Die attach crack growth is measured through cycling and found to be in excellent agreement with simulations of the inelastic strain energy accumulated. Simulations of an entire year of weather data provides for the relative ranking of fatigue damage between four cities as well as their equivalent accelerated test time.

An induction reactor for studying crude-oil oxidation relevant to in situ combustion.

PubMed

Bazargan, Mohammad; Lapene, Alexandre; Chen, Bo; Castanier, Louis M; Kovscek, Anthony R

2013-07-01

In a conventional ramped temperature oxidation kinetics cell experiment, an electrical furnace is used to ramp temperature at a prescribed rate. Thus, the heating rate of a kinetics cell experiment is limited by furnace performance to heating rates of about 0.5-3 °C/min. A new reactor has been designed to overcome this limit. It uses an induction heating method to ramp temperature. Induction heating is fast and easily controlled. The new reactor covers heating rates from 1 to 30 °C/min. This is the first time that the oxidation profiles of a crude oil are available over such a wide range of heating rate. The results from an induction reactor and a conventional kinetics cell at roughly 2 °C/min are compared to illustrate consistency between the two reactors. The results at low heating rate are the same as the conventional kinetics cell. As presented in the paper, the new reactor couples well with the isoconversional method for interpretation of reaction kinetics.

Does Stepwise Voltage Ramping Protect the Kidney from Injury During Extracorporeal Shockwave Lithotripsy? Results of a Prospective Randomized Trial.

PubMed

Skuginna, Veronika; Nguyen, Daniel P; Seiler, Roland; Kiss, Bernhard; Thalmann, George N; Roth, Beat

2016-02-01

Renal damage is more frequent with new-generation lithotripters. However, animal studies suggest that voltage ramping minimizes the risk of complications following extracorporeal shock wave lithotripsy (SWL). In the clinical setting, the optimal voltage strategy remains unclear. To evaluate whether stepwise voltage ramping can protect the kidney from damage during SWL. A total of 418 patients with solitary or multiple unilateral kidney stones were randomized to receive SWL using a Modulith SLX-F2 lithotripter with either stepwise voltage ramping (n=213) or a fixed maximal voltage (n=205). SWL. The primary outcome was sonographic evidence of renal hematomas. Secondary outcomes included levels of urinary markers of renal damage, stone disintegration, stone-free rate, and rates of secondary interventions within 3 mo of SWL. Descriptive statistics were used to compare clinical outcomes between the two groups. A logistic regression model was generated to assess predictors of hematomas. Significantly fewer hematomas occurred in the ramping group(12/213, 5.6%) than in the fixed group (27/205, 13%; p=0.008). There was some evidence that the fixed group had higher urinary β2-microglobulin levels after SWL compared to the ramping group (p=0.06). Urinary microalbumin levels, stone disintegration, stone-free rate, and rates of secondary interventions did not significantly differ between the groups. The logistic regression model showed a significantly higher risk of renal hematomas in older patients (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.00-1.05; p=0.04). Stepwise voltage ramping was associated with a lower risk of hematomas (OR 0.39, 95% CI 0.19-0.80; p=0.01). The study was limited by the use of ultrasound to detect hematomas. In this prospective randomized study, stepwise voltage ramping during SWL was associated with a lower risk of renal damage compared to a fixed maximal voltage without compromising treatment effectiveness. Lithotripsy is a noninvasive technique for urinary stone disintegration using ultrasonic energy. In this study, two voltage strategies are compared. The results show that a progressive increase in voltage during lithotripsy decreases the risk of renal hematomas while maintaining excellent outcomes. ISRCTN95762080. Copyright © 2015 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Orion Service Module Reaction Control System Plume Impingement Analysis Using PLIMP/RAMP2

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen; Lumpkin, Forrest E., III; Gati, Frank; Yuko, James R.; Motil, Brian J.

2009-01-01

The Orion Crew Exploration Vehicle Service Module Reaction Control System engine plume impingement was computed using the plume impingement program (PLIMP). PLIMP uses the plume solution from RAMP2, which is the refined version of the reacting and multiphase program (RAMP) code. The heating rate and pressure (force and moment) on surfaces or components of the Service Module were computed. The RAMP2 solution of the flow field inside the engine and the plume was compared with those computed using GASP, a computational fluid dynamics code, showing reasonable agreement. The computed heating rate and pressure using PLIMP were compared with the Reaction Control System plume model (RPM) solution and the plume impingement dynamics (PIDYN) solution. RPM uses the GASP-based plume solution, whereas PIDYN uses the SCARF plume solution. Three sets of the heating rate and pressure solutions agree well. Further thermal analysis on the avionic ring of the Service Module was performed using MSC Patran/Pthermal. The obtained temperature results showed that thermal protection is necessary because of significant heating from the plume.

Can Horizontal Hydraulic Fracturing Lead to Less Expensive Achievement of More Natural River Flows?

NASA Astrophysics Data System (ADS)

Kern, J.; Characklis, G. W.

2014-12-01

High ramp rates and low costs make hydropower an extremely valuable resource for meeting "peak" hourly electricity demands, but dams that employ variable, stop-start reservoir releases can have adverse impacts on downstream riverine ecosystems. In recent years, efforts to mitigate the environmental impacts of hydropower peaking have relied predominantly on the use of ramp rate restrictions, or limits on the magnitude of hour-to-hour changes in reservoir discharge. These restrictions shift some hydropower production away from peak hours towards less valuable off-peak hours and impose a financial penalty on dam owners that is a function of: 1) the "spread" (difference) between peak and off-peak electricity prices; and 2) the total amount of generation shifted from peak to off-peak hours. In this study, we show how variability in both the price spread and reservoir inflows can cause large swings in the financial cost of ramp rate restrictions on a seasonal and annual basis. Of particular interest is determining whether current low natural gas prices (largely attributable to improvements in hydraulic fracturing) have reduced the cost of implementing ramp rate restrictions at dams by narrowing the spread between peak and off-peak electricity prices. We also examine the role that large year-to-year fluctuations in the cost of ramp rate restrictions may play in precluding downstream stakeholders (e.g., conservation trusts) from "purchasing" more natural streamflow patterns from dam owners. In recent years, similar arrangements between conservation trusts and consumptive water users have been put into practice in the U.S. for the purposes of supplementing baseflows in rivers. However, significant year-to-year uncertainty in the size of payments necessary to compensate hydropower producers for lost peaking production (i.e., uncertainty in the cost of ramp rate restrictions) makes transactions that aim to mitigate the environmental impacts of hydropower peaking untenable. In order to reduce this financial uncertainty, we propose the use of "collar" agreements between a downstream stakeholder and a third party insurer that would provide a stable price for parties "buying" more natural flows.

Reprocessing WFC3/IR Exposures Affected by Time-Variable Backgrounds

NASA Astrophysics Data System (ADS)

Brammer, G.

2016-11-01

The background seen in WFC3/IR observations frequently shows strong time-dependent behavior above the constant flux expected for zodiacal continuum light. This is often caused by an emission line of helium at 1.083 μm excited in the sun-illuminated upper atmosphere, when seen in the filters (F105W, F110W) and grisms (G102, G141) sensitive to the feature. The default behavior of the calwf3 pipeline assumes constant source-plus-background fluxes when it performs up-the-ramp fitting to identify cosmic rays and determine the average count rate within a MULTIACCUM IR exposure. calwf3 provides undesirable results in the presence of strongly variable backgrounds, primarily in the form of elevated and non-Gaussian noise in the FLT products. Here we describe methods to improve the noise properties of the reduced products. In the first, we simply turn off the calwf3 crcorr step, treating the IR detector as if it were a CCD, i.e., accumulating flux and reading it out at the end of the exposure. Next, we artificially flatten the ramps in the IMA products and then allow calwf3 to proceed as normal fitting the ramp and identifying CRs. Either of these procedures enable recovery of datasets otherwise corrupted beyond repair and have no discernible effects on photometry of sources in deep combined images.

Vibratory high pressure coal feeder having a helical ramp

DOEpatents

Farber, Gerald

1978-01-01

Apparatus and method for feeding powdered coal from a helical ramp into a high pressure, heated, reactor tube containing hydrogen for hydrogenating the coal and/or for producing useful products from coal. To this end, the helical ramp is vibrated to feed the coal cleanly at an accurately controlled rate in a simple reliable and trouble-free manner that eliminates complicated and expensive screw feeders, and/or complicated and expensive seals, bearings and fully rotating parts.

High precision triangular waveform generator

DOEpatents

Mueller, Theodore R.

1983-01-01

An ultra-linear ramp generator having separately programmable ascending and descending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.

High-precision triangular-waveform generator

DOEpatents

Mueller, T.R.

1981-11-14

An ultra-linear ramp generator having separately programmable ascending and decending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.

Evaluation of WRF-Predicted Near-Hub-Height Winds and Ramp Events over a Pacific Northwest Site with Complex Terrain

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

Yang, Qing; Berg, Larry K.; Pekour, Mikhail

The WRF model version 3.3 is used to simulate near hub-height winds and power ramps utilizing three commonly used planetary boundary-layer (PBL) schemes: Mellor-Yamada-Janjic (MYJ), University of Washington (UW), and Yonsei University (YSU). The predicted winds have small mean biases compared with observations. Power ramps and step changes (changes within an hour) consistently show that the UW scheme performed better in predicting up ramps under stable conditions with higher prediction accuracy and capture rates. Both YSU and UW scheme show good performance predicting up- and down- ramps under unstable conditions with YSU being slightly better for ramp durations longer thanmore » an hour. MYJ is the most successful simulating down-ramps under stable conditions. The high wind speed and large shear associated with low-level jets are frequently associated with power ramps, and the biases in predicted low-level jet explain some of the shown differences in ramp predictions among different PBL schemes. Low-level jets were observed as low as ~200 m in altitude over the Columbia Basin Wind Energy Study (CBWES) site, located in an area of complex terrain. The shear, low-level peak wind speeds, as well as the height of maximum wind speed are not well predicted. Model simulations with 3 PBL schemes show the largest variability among them under stable conditions.« less

Transient flow combustion

NASA Technical Reports Server (NTRS)

Tacina, R. R.

1984-01-01

Non-steady combustion problems can result from engine sources such as accelerations, decelerations, nozzle adjustments, augmentor ignition, and air perturbations into and out of the compressor. Also non-steady combustion can be generated internally from combustion instability or self-induced oscillations. A premixed-prevaporized combustor would be particularly sensitive to flow transients because of its susceptability to flashback-autoignition and blowout. An experimental program, the Transient Flow Combustion Study is in progress to study the effects of air and fuel flow transients on a premixed-prevaporized combustor. Preliminary tests performed at an inlet air temperature of 600 K, a reference velocity of 30 m/s, and a pressure of 700 kPa. The airflow was reduced to 1/3 of its original value in a 40 ms ramp before flashback occurred. Ramping the airflow up has shown that blowout is more sensitive than flashback to flow transients. Blowout occurred with a 25 percent increase in airflow (at a constant fuel-air ratio) in a 20 ms ramp. Combustion resonance was found at some conditions and may be important in determining the effects of flow transients.

Truck accidents at freeway ramps : data analysis and high-risk site identification

DOT National Transportation Integrated Search

1998-01-01

To examine the relationship of ramp design to truck accident rates, this paper presents an analysis of truck accidents in Washington State, plus a comparison to limited data from Colorado and California. The authors group freeway truck accidents by r...

Impacts of Wind and Solar on Fossil-Fueled Generators: Preprint

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

Lew, D.; Brinkman, G.; Kumar, N.

2012-08-01

High penetrations of wind and solar power will impact the operations of the remaining generators on the power system. Regional integration studies have shown that wind and solar may cause fossil-fueled generators to cycle on and off and ramp down to part load more frequently and potentially more rapidly. Increased cycling, deeper load following, and rapid ramping may result in wear-and-tear impacts on fossil-fueled generators that lead to increased capital and maintenance costs, increased equivalent forced outage rates, and degraded performance over time. Heat rates and emissions from fossil-fueled generators may be higher during cycling and ramping than during steady-statemore » operation. Many wind and solar integration studies have not taken these increased cost and emissions impacts into account because data have not been available. This analysis considers the cost and emissions impacts of cycling and ramping of fossil-fueled generation to refine assessments of wind and solar impacts on the power system.« less

The Future Impact of Wind on BPA Power System Ancillary Services

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

Makarov, Yuri V.; Lu, Shuai; McManus, Bart

Wind power is growing in a very fast pace as an alternative generating resource. As the ratio of wind power over total system capacity increases, the impact of wind on various system aspects becomes significant. This paper presents a methodology to study the future impact of wind on BPA power system ancillary services including load following and regulation. Existing approaches for similar analysis include dispatch model simulation and standard deviation evaluation. The methodology proposed in this paper uses historical data and stochastic processes to simulate the load balancing processes in BPA power system. Then capacity, ramp rate and ramp durationmore » characteristics are extracted from the simulation results, and load following and regulation requirements are calculated accordingly. It mimics the actual power system operations therefore the results can be more realistic yet the approach is convenient to perform. Further, the ramp rate and ramp duration data obtained from the analysis can be used to evaluate generator response or maneuverability and energy requirement, respectively, additional to the capacity requirement.« less

Dynamic tensile fracture of mortar at ultra-high strain-rates

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

Erzar, B., E-mail: benjamin.erzar@cea.fr; Buzaud, E.; Chanal, P.-Y.

2013-12-28

During the lifetime of a structure, concrete and mortar may be exposed to highly dynamic loadings, such as impact or explosion. The dynamic fracture at high loading rates needs to be well understood to allow an accurate modeling of this kind of event. In this work, a pulsed-power generator has been employed to conduct spalling tests on mortar samples at strain-rates ranging from 2 × 10{sup 4} to 4 × 10{sup 4} s{sup −1}. The ramp loading allowed identifying the strain-rate anytime during the test. A power law has been proposed to fit properly the rate-sensitivity of tensile strength of thismore » cementitious material over a wide range of strain-rate. Moreover, a specimen has been recovered damaged but unbroken. Micro-computed tomography has been employed to study the characteristics of the damage pattern provoked by the dynamic tensile loading.« less

Optimizing the current ramp-up phase for the hybrid ITER scenario

NASA Astrophysics Data System (ADS)

Hogeweij, G. M. D.; Artaud, J.-F.; Casper, T. A.; Citrin, J.; Imbeaux, F.; Köchl, F.; Litaudon, X.; Voitsekhovitch, I.; the ITM-TF ITER Scenario Modelling Group

2013-01-01

The current ramp-up phase for the ITER hybrid scenario is analysed with the CRONOS integrated modelling suite. The simulations presented in this paper show that the heating systems available at ITER allow, within the operational limits, the attainment of a hybrid q profile at the end of the current ramp-up. A reference ramp-up scenario is reached by a combination of NBI, ECCD (UPL) and LHCD. A heating scheme with only NBI and ECCD can also reach the target q profile; however, LHCD can play a crucial role in reducing the flux consumption during the ramp-up phase. The optimum heating scheme depends on the chosen transport model, and on assumptions of parameters like ne peaking, edge Te,i and Zeff. The sensitivity of the current diffusion on parameters that are not easily controlled, shows that development of real-time control is important to reach the target q profile. A first step in that direction has been indicated in this paper. Minimizing resistive flux consumption and optimizing the q profile turn out to be conflicting requirements. A trade-off between these two requirements has to be made. In this paper it is shown that fast current ramp with L-mode current overshoot is at the one extreme, i.e. the optimum q profile at the cost of increased resistive flux consumption, whereas early H-mode transition is at the other extreme.

Strain-rate dependence of ramp-wave evolution and strength in tantalum

DOE PAGES

Lane, J. Matthew D.; Foiles, Stephen M.; Lim, Hojun; ...

2016-08-25

We have conducted molecular dynamics (MD) simulations of quasi-isentropic ramp-wave compression to very high pressures over a range of strain rates from 10 11 down to 10 8 1/s. Using scaling methods, we collapse wave profiles from various strain rates to a master profile curve, which shows deviations when material response is strain-rate dependent. Thus, we can show with precision where, and how, strain-rate dependence affects the ramp wave. We find that strain rate affects the stress-strain material response most dramatically at strains below 20%, and that above 30% strain the material response is largely independent of strain rate. Wemore » show good overall agreement with experimental stress-strain curves up to approximately 30% strain, above which simulated response is somewhat too stiff. We postulate that this could be due to our interatomic potential or to differences in grain structure and/or size between simulation and experiment. Strength is directly measured from per-atom stress tensor and shows significantly enhanced elastic response at the highest strain rates. As a result, this enhanced elastic response is less pronounced at higher pressures and at lower strain rates.« less

Anomalous current diffusion and improved confinement in the HT-6M tohamak

NASA Astrophysics Data System (ADS)

Gao, X.; Li, J. G.; Wan, Y. X.; Huo, Y. P.; Guo, W. K.; Fan, S. P.; Yu, C. X.; Luo, J. R.; Yin, F. X.; Meng, Y. D.; Zheng, L.; Yin, F.; Lin, B. L.; Zhang, S. Y.; Wang, S. Y.; Lu, H. J.; Liu, S. X.; Tong, X. D.; Ding, L. C.; Wu, Z. Y.; Yin, X. J.; Guo, Q. L.; Gong, X. Z.; Wu, X. C.; Zhao, J. Y.; Xi, J. S.

1994-10-01

Current diffusion was studied during edge ohmic heating (EOH) experiments in the HT-6M tokamak. The EOH power system makes the plasma current linearly ramp up from an initial steady state ( Ip=55kA) to a second steady state ( Ip=60kA) at a fast ramp rate of 12 MA/s. A stable discharge of an improved confinement was observed experimentally in the HT-6M tokamak after the plasma current was ramped to rise rapidly to a second steady state. The plasma current is ramped up much faster than both the classical skin time and neoclassical skin time. Fast current ramp up increases the anomalous current diffusion. The measured values of {β P+l i}/{2} and the soft X-ray sawtooth inversion radius imply the anomalous current penetration. The mechanism of anomalous penetration and improved confinement is discussed.

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

NASA Astrophysics Data System (ADS)

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

2013-12-01

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

Optimal pricing and lot-sizing for perishable inventory with price and time dependent ramp-type demand

NASA Astrophysics Data System (ADS)

Panda, S.; Saha, S.; Basu, M.

2013-01-01

Product perishability is an important aspect of inventory control. To minimise the effect of deterioration, retailers in supermarkets, departmental store managers, etc. always want higher inventory depletion rate. In this article, we propose a dynamic pre- and post-deterioration cumulative discount policy to enhance inventory depletion rate resulting low volume of deterioration cost, holding cost and hence higher profit. It is assumed that demand is a price and time dependent ramp-type function and the product starts to deteriorate after certain amount of time. Unlike the conventional inventory models with pricing strategies, which are restricted to a fixed number of price changes and to a fixed cycle length, we allow the number of price changes before as well as after the start of deterioration and the replenishment cycle length to be the decision variables. Before start of deterioration, discounts on unit selling price are provided cumulatively in successive pricing cycles. After the start of deterioration, discounts on reduced unit selling price are also provided in a cumulative way. A mathematical model is developed and the existence of the optimal solution is verified. A numerical example is presented, which indicates that under the cumulative effect of price discounting, dynamic pricing policy outperforms static pricing strategy. Sensitivity analysis of the model is carried out.

Rolling and aging in temperature-ramp soft adhesion

NASA Astrophysics Data System (ADS)

Boniello, Giuseppe; Tribet, Christophe; Marie, Emmanuelle; Croquette, Vincent; Zanchi, Dražen

2018-01-01

Immediately before adsorption to a horizontal substrate, sinking polymer-coated colloids can undergo a complex sequence of landing, jumping, crawling, and rolling events. Using video tracking, we studied the soft adhesion to a horizontal flat plate of micron-size colloids coated by a controlled molar fraction f of the poly(lysine)-grafted-poly(N-isopropylacrylamide) (PLL-g-PNIPAM) which is a temperature-sensitive polymer. We ramp the temperature from below to above Tc=32 ±1∘C , at which the PNIPAM polymer undergoes a transition, triggering attractive interaction between microparticles and surface. The adsorption rate, the effective in-plane (x -y ) diffusion constant, and the average residence time distribution over z were extracted from the Brownian motion records during last seconds before immobilization. Experimental data are understood within a rate-equations-based model that includes aging effects and includes three populations: the untethered, the rolling, and the arrested colloids. We show that preadsorption dynamics casts a characteristic scaling function α (f ) proportional to the number of available PNIPAM patches met by soft contact during Brownian rolling. In particular, the increase of in-plane diffusivity with increasing f is understood: The stickiest particles have the shortest rolling regime prior to arrest, so that their motion is dominated by the untethered phase.

Radar echo processing with partitioned de-ramp

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

Dubbert, Dale F.; Tise, Bertice L.

2013-03-19

The spurious-free dynamic range of a wideband radar system is increased by apportioning de-ramp processing across analog and digital processing domains. A chirp rate offset is applied between the received waveform and the reference waveform that is used for downconversion to the intermediate frequency (IF) range. The chirp rate offset results in a residual chirp in the IF signal prior to digitization. After digitization, the residual IF chirp is removed with digital signal processing.

Assessment of peak oxygen uptake during handcycling: Test-retest reliability and comparison of a ramp-incremented and perceptually-regulated exercise test.

PubMed

Hutchinson, Michael J; Paulson, Thomas A W; Eston, Roger; Goosey-Tolfrey, Victoria L

2017-01-01

To examine the reliability of a perceptually-regulated maximal exercise test (PRETmax) to measure peak oxygen uptake ([Formula: see text]) during handcycle exercise and to compare peak responses to those derived from a ramp-incremented protocol (RAMP). Twenty recreationally active individuals (14 male, 6 female) completed four trials across a 2-week period, using a randomised, counterbalanced design. Participants completed two RAMP protocols (20 W·min-1) in week 1, followed by two PRETmax in week 2, or vice versa. The PRETmax comprised five, 2-min stages clamped at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20. Participants changed power output (PO) as often as required to maintain target RPE. Gas exchange variables (oxygen uptake, carbon dioxide production, minute ventilation), heart rate (HR) and PO were collected throughout. Differentiated RPE were collected at the end of each stage throughout trials. For relative [Formula: see text], coefficient of variation (CV) was equal to 4.1% and 4.8%, with ICC(3,1) of 0.92 and 0.85 for repeated measures from PRETmax and RAMP, respectively. Measurement error was 0.15 L·min-1 and 2.11 ml·kg-1·min-1 in PRETmax and 0.16 L·min-1 and 2.29 ml·kg-1·min-1 during RAMP for determining absolute and relative [Formula: see text], respectively. The difference in [Formula: see text] between PRETmax and RAMP was tending towards statistical significance (26.2 ± 5.1 versus 24.3 ± 4.0 ml·kg-1·min-1, P = 0.055). The 95% LoA were -1.9 ± 4.1 (-9.9 to 6.2) ml·kg-1·min-1. The PRETmax can be used as a reliable test to measure [Formula: see text] during handcycle exercise in recreationally active participants. Whilst PRETmax tended towards significantly greater [Formula: see text] values than RAMP, the difference is smaller than measurement error of determining [Formula: see text] from PRETmax and RAMP.

A Copula-Based Conditional Probabilistic Forecast Model for Wind Power Ramps

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

Hodge, Brian S; Krishnan, Venkat K; Zhang, Jie

Efficient management of wind ramping characteristics can significantly reduce wind integration costs for balancing authorities. By considering the stochastic dependence of wind power ramp (WPR) features, this paper develops a conditional probabilistic wind power ramp forecast (cp-WPRF) model based on Copula theory. The WPRs dataset is constructed by extracting ramps from a large dataset of historical wind power. Each WPR feature (e.g., rate, magnitude, duration, and start-time) is separately forecasted by considering the coupling effects among different ramp features. To accurately model the marginal distributions with a copula, a Gaussian mixture model (GMM) is adopted to characterize the WPR uncertaintymore » and features. The Canonical Maximum Likelihood (CML) method is used to estimate parameters of the multivariable copula. The optimal copula model is chosen based on the Bayesian information criterion (BIC) from each copula family. Finally, the best conditions based cp-WPRF model is determined by predictive interval (PI) based evaluation metrics. Numerical simulations on publicly available wind power data show that the developed copula-based cp-WPRF model can predict WPRs with a high level of reliability and sharpness.« less

Comparison of algorithms of testing for use in automated evaluation of sensation.

PubMed

Dyck, P J; Karnes, J L; Gillen, D A; O'Brien, P C; Zimmerman, I R; Johnson, D M

1990-10-01

Estimates of vibratory detection threshold may be used to detect, characterize, and follow the course of sensory abnormality in neurologic disease. The approach is especially useful in epidemiologic and controlled clinical trials. We studied which algorithm of testing and finding threshold should be used in automatic systems by comparing among algorithms and stimulus conditions for the index finger of healthy subjects and for the great toe of patients with mild neuropathy. Appearance thresholds obtained by linear ramps increasing at a rate less than 4.15 microns/sec provided accurate and repeatable thresholds compared with thresholds obtained by forced-choice testing. These rates would be acceptable if only sensitive sites were studied, but they were too slow for use in automatic testing of insensitive parts. Appearance thresholds obtained by fast linear rates (4.15 or 16.6 microns/sec) overestimated threshold, especially for sensitive parts. Use of the mean of appearance and disappearance thresholds, with the stimulus increasing exponentially at rates of 0.5 or 1.0 just noticeable difference (JND) units per second, and interspersion of null stimuli, Békésy with null stimuli, provided accurate, repeatable, and fast estimates of threshold for sensitive parts. Despite the good performance of Békésy testing, we prefer forced choice for evaluation of the sensation of patients with neuropathy.

Buried Oxide Densification for Low Power, Low Voltage CMOS Applications

NASA Technical Reports Server (NTRS)

Allen, L. P.; Anc, M. J.; Dolan, B.; Jiao, J.; Guss, B.; Seraphin, S.; Liu, S. T.; Jenkins, W.

1998-01-01

Special technology and circuit architecture are of growing interest for implementation of circuits which operate at low supply voltages and consume low power levels without sacrificing performance[1]. Use of thin buried oxide SOI substrates is a primary approach to simultaneously achieve these goals. A significant aspect regarding SIMOX SOI for low voltage, low power applications is the reliability and performance of the thin buried oxide. In addition, when subjected to high total dose irradiation, the silicon islands within the BOX layer of SIMOX can store charges and significantly effect the back channel threshold voltages of devices. Thus, elimination of the islands within the buried oxide (BOX) layer is preferred in order to prevent leakage through these conductive islands and charge build-up within the buried oxide layer. A differential (2-step) ramp rate as applied to full and 100 nm BOX SIMOX was previously reported to play a significant role in the stoichiometry and island formation within the buried layer[2]. This paper focus is on the properties of a thin (120nm) buried oxide as a function of the anneal ramp rate and the temperature of anneal. In this research, we have found an improvement in the buried oxide stoichiometry with the use of a slower, singular ramp rate for specified thin buried oxides, with slower ramp rates and higher temperatures of anneal suggested for reducing the presence of Si islands within the BOX layer.

Sequential power-up circuit

DOEpatents

Kronberg, James W.

1992-01-01

A sequential power-up circuit for starting several electrical load elements in series to avoid excessive current surge, comprising a voltage ramp generator and a set of voltage comparators, each comparator having a different reference voltage and interfacing with a switch that is capable of turning on one of the load elements. As the voltage rises, it passes the reference voltages one at a time and causes the switch corresponding to that voltage to turn on its load element. The ramp is turned on and off by a single switch or by a logic-level electrical signal. The ramp rate for turning on the load element is relatively slow and the rate for turning the elements off is relatively fast. Optionally, the duration of each interval of time between the turning on of the load elements is programmable.

The Future Impact of Wind on BPA Power System Load Following and Regulation Requirements

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

Makarov, Yuri V.; Lu, Shuai; McManus, Bart

Wind power is growing in a very fast pace as an alternative generating resource. As the ratio of wind power over total system capacity increases, the impact of wind on various system aspects becomes significant. This paper presents a methodology to study the future impact of wind on BPA power system load following and regulation requirements. Existing methodologies for similar analysis include dispatch model simulation and standard deviation evaluation on load and wind data. The methodology proposed in this paper uses historical data and stochastic processes to simulate the load balancing processes in the BPA power system. It mimics themore » actual power system operations therefore the results are close to reality yet the study based on this methodology is convenient to perform. The capacity, ramp rate and ramp duration characteristics are extracted from the simulation results. System load following and regulation capacity requirements are calculated accordingly. The ramp rate and ramp duration data obtained from the analysis can be used to evaluate generator response or maneuverability requirement and regulating units’ energy requirement, respectively.« less

Puente Hills blind-thrust system, Los Angeles, California

USGS Publications Warehouse

Shaw, J.H.; Plesch, A.; Dolan, J.F.; Pratt, T.L.; Fiore, P.

2002-01-01

We describe the three-dimensional geometry and Quaternary slip history of the Puente Hills blind-thrust system (PHT) using seismic reflection profiles, petroleum well data, and precisely located seismicity. The PHT generated the 1987 Whittier Narrows (moment magnitude [Mw] 6.0) earthquake and extends for more than 40 km along strike beneath the northern Los Angeles basin. The PHT comprises three, north-dipping ramp segments that are overlain by contractional fault-related folds. Based on an analysis of these folds, we produce Quaternary slip profiles along each ramp segment. The fault geometry and slip patterns indicate that segments of the PHT are related by soft-linkage boundaries, where the fault ramps are en echelon and displacements are gradually transferred from one segment to the next. Average Quaternary slip rates on the ramp segments range from 0.44 to 1.7 mm/yr, with preferred rates between 0.62 and 1.28 mm/yr. Using empirical relations among rupture area, magnitude, and coseismic displacement, we estimate the magnitude and frequency of single (Mw 6.5-6.6) and multisegment (Mw 7.1) rupture scenarios for the PHT.

Effects of onion extract on endogenous vascular H2S and adrenomedulin in rat atherosclerosis.

PubMed

Li, Wei; Tang, Chaoshu; Jin, Hongfang; Du, Junbao

2011-09-01

This study aimed to explore the effect of onion extract on endogenous hydrogen sulfide (H2S) and adrenomedulin (ADM) and on atherosclerotic progression in rats with atherosclerosis (AS). Male Sprague-Dawley rats were randomly divided into control, AS and AS+onion groups. Ultrastructure of aorta and atherosclerotic lesions both in aorta and in coronary artery were detected. Plasma and aortic H2S were detected by using a sulfide- sensitive electrode. Plasma and aortic ADM was determined with radioimmunoassay. Cystathionine-γ-lyase (CSE), calcitonin receptor-like receptor (CRLR), receptor activity-modifying protein (RAMP1, RAMP2 and RAMP3) mRNA expressions were analysed. Glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO) and NO synthase (NOS) contents in plasma, SOD1, SOD2 and ICAM-1 expressions in aorta were detected. Rats in the AS group showed marked atherosclerotic lesions both in aorta and in coronary artery but decreased aortic H2S production. Decreased plasma and aortic ADM content, but increased levels of aortic CRLR, RAMP2 and RAMP3 mRNAs were observed. Plasma GSH-PX and SOD were reduced but MDA elevated. Plasma ICAM-1 and NO contents and iNOS activity were increased. Onion extract, however, lessened atherosclerotic lesions and increased endogenous aortic H2S production, but decreased plasma ADM content, aortic ADM content and aortic CRLR, RAMP2 and RAMP3 mRNAs. In addition, it increased plasma GSH-PX level and SOD activities but reduced MDA; it decreased inflammatory response but increased plasma eNOS activity and NO content. Onion extract exerted a marked antiatherogenic effect in association with the up-regulation of the endogenous CSE/H2S pathway but down-regulation of the ADM/CRLR family in atherosclerotic rats.

Comparison of Bruce treadmill exercise test protocols: is ramped Bruce equal or superior to standard bruce in producing clinically valid studies for patients presenting for evaluation of cardiac ischemia or arrhythmia with body mass index equal to or greater than 30?

PubMed

Bires, Angela Macci; Lawson, Dori; Wasser, Thomas E; Raber-Baer, Donna

2013-12-01

Clinically valid cardiac evaluation via treadmill stress testing requires patients to achieve specific target heart rates and to successfully complete the cardiac examination. A comparison of the standard Bruce protocol and the ramped Bruce protocol was performed using data collected over a 1-y period from a targeted patient population with a body mass index (BMI) equal to or greater than 30 to determine which treadmill protocol provided more successful examination results. The functional capacity, metabolic equivalent units achieved, pressure rate product, and total time on the treadmill as measured for the obese patients were clinically valid and comparable to normal-weight and overweight patients (P < 0.001). Data gathered from each protocol demonstrated that the usage of the ramped Bruce protocol achieved more consistent results in comparison across all BMI groups in achieving 80%-85% of their age-predicted maximum heart rate. This study did not adequately establish that the ramped Bruce protocol was superior to the standard Bruce protocol for the examination of patients with a BMI equal to or greater than 30.

Start-up performance of parabolic trough concentrating solar power plants

NASA Astrophysics Data System (ADS)

Ferruzza, Davide; Topel, Monika; Basaran, Ibrahim; Laumert, Björn; Haglind, Fredrik

2017-06-01

Concentrating solar power plants, even though they can be integrated with thermal energy storage, are still subjected to cyclic start-up and shut-downs. As a consequence, in order to maximize their profitability and performance, the flexibility with respect to transient operations is essential. In this regard, two of the key components identified are the steam generation system and steam turbine. In general it is desirable to have fast ramp-up rates during the start-up of a power plant. However ramp-up rates are limited by, among other things, thermal stresses, which if high enough can compromise the life of the components. Moreover, from an operability perspective it might not be optimal to have designs for the highest heating rates, as there may be other components limiting the power plant start-up. Therefore, it is important to look at the interaction between the steam turbine and steam generator to determine the optimal ramp rates. This paper presents a methodology to account for thermal stresses limitations during the power plant start up, aiming at identifying which components limit the ramp rates. A detailed dynamic model of a parabolic trough power plant was developed and integrated with a control strategy to account for the start-up limitations of both the turbine and steam generator. The models have been introduced in an existing techno-economic tool developed by the authors (DYESOPT). The results indicated that for each application, an optimal heating rates range can be identified. For the specific case presented in the paper, an optimal range of 7-10 K/min of evaporator heating rate can result in a 1.7-2.1% increase in electricity production compared to a slower component (4 K/min).

Sequential power-up circuit

DOEpatents

Kronberg, J.W.

1992-06-02

A sequential power-up circuit for starting several electrical load elements in series to avoid excessive current surge, comprising a voltage ramp generator and a set of voltage comparators, each comparator having a different reference voltage and interfacing with a switch that is capable of turning on one of the load elements. As the voltage rises, it passes the reference voltages one at a time and causes the switch corresponding to that voltage to turn on its load element. The ramp is turned on and off by a single switch or by a logic-level electrical signal. The ramp rate for turning on the load element is relatively slow and the rate for turning the elements off is relatively fast. Optionally, the duration of each interval of time between the turning on of the load elements is programmable. 2 figs.

Increased Coal Plant Flexibility Can Improve Renewables Integration |

Science.gov Websites

practices that enable lower turndowns, faster starts and stops, and faster ramping between load set-points faster ramp rates and faster and less expensive starts. Flexible Load - Demand Response Resources Demand response (DR) is a load management practice of deliberately reducing or adding load to balance the system

Ramped-rate vs continuous-rate infusions: An in vitro comparison of convection enhanced delivery protocols.

PubMed

Schomberg, Dominic; Wang, Anyi; Marshall, Hope; Miranpuri, Gurwattan; Sillay, Karl

2013-04-01

Convection enhanced delivery (CED) is a technique using infusion convection currents to deliver therapeutic agents into targeted regions of the brain. Recently, CED is gaining significant acceptance for use in gene therapy of Parkinson's disease (PD) employing direct infusion into the brain. CED offers advantages in that it targets local areas of the brain, bypasses the blood-brain barrier (BBB), minimizes systemic toxicity of the therapeutics, and allows for delivery of larger molecules that diffusion driven methods cannot achieve. Investigating infusion characteristics such as backflow and morphology is important in developing standard and effective protocols in order to successfully deliver treatments into the brain. Optimizing clinical infusion protocols may reduce backflow, improve final infusion cloud morphology, and maximize infusate penetrance into targeted tissue. The purpose of the current study was to compare metrics during ramped-rate and continuous-rate infusions using two different catheters in order to optimize current infusion protocols. Occasionally, the infusate refluxes proximally up the catheter tip, known as backflow, and minimizing this can potentially reduce undesirable effects in the clinical setting. Traditionally, infusions are performed at a constant rate throughout the entire duration, and backflow is minimized only by slow infusion rates, which increases the time required to deliver the desired amount of infusate. In this study, we investigate the effects of ramping and various infusion rates on backflow and infusion cloud morphology. The independent parameters in the study are: ramping, maximum infusion rate, time between rate changes, and increments of rate changes. Backflow was measured using two methods: i) at the point of pressure stabilization within the catheter, and ii) maximum backflow as shown by video data. Infusion cloud morphology was evaluated based on the height-to-width ratio of each infusion cloud at the end of each experiment. Results were tabulated and statistically analyzed to identify any significant differences between protocols. The experimental results show that CED rampedrate infusion protocols result in smaller backflow distances and more spherical cloud morphologies compared to continuous-rate infusion protocols ending at the same maximum infusion rate. Our results also suggest internal-line pressure measurements can approximate the time-point at which backflow ceases. Our findings indicate that ramping CED infusion protocols can potentially minimize backflow and produce more spherical infusion clouds. However, further research is required to determine the strength of this correlation, especially in relation to maximum infusion rates.

Evaluating the Functionality and Usability of Two Novel Wheelchair Anti-Rollback Devices for Ramp Ascent in Manual Wheelchair Users With Spinal Cord Injury.

PubMed

Deems-Dluhy, Susan L; Jayaraman, Chandrasekaran; Green, Steve; Albert, Mark V; Jayaraman, Arun

2017-05-01

Difficulty ascending ramps and inclines with a manual wheelchair adversely affects the everyday mobility and overall quality of life of manual wheelchair users. Currently, various anti-rollback devices are available to assist manual wheelchair users to ascend ramps and inclines. However, these devices have 2 main shortcomings: restriction to backward motion limiting recovery from an overturning wheelchair, which is a safety concern; and difficulty in engaging/disengaging the device while on the ramp. To evaluate the functionality and usability of 2 novel wheelchair anti-rollback devices developed to address these shortcomings (prototypes "Wheel" and "Brake"). Cross-sectional. Rehabilitation research facility. Twelve adult participants with chronic spinal cord injury. Participants completed training and tested with both the wheelchair anti-rollback devices on a 7.3-m-long ramp. Number of stops, perceived physical exertion, pain, and ease of use of these devices as participants maneuvered their wheelchairs up a 7.3-m ramp were assessed. Participants also evaluated their satisfaction with the usability of both the devices using the Quebec User Evaluation of Satisfaction With Assistive Technology (QUEST 2.0). Both prototypes evaluated overcame the limitations of the existing anti-rollback devices. Nonparametric statistical tests showed that participants rated both prototypes similarly for the overall functional and usability aspects. However, the participants' satisfactory rating were higher for the prototype "Brake" than for the prototype "Wheel" based on a functional aspect (ie, engaging/disengaging easiness), and higher for Wheel than for Brake, based on a usability aspect (prototype size). The qualitative and quantitative outcomes of this investigation, based on the usability and functional evaluations, provided useful information for the improvement in the design of both anti-rollback devices, which may allow manual wheelchair users to manage ramp ascent more safely and easily. Further evaluations with a different SCI population is recommended. IV. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Increased cardiac output elicits higher V̇O2max in response to self-paced exercise.

PubMed

Astorino, Todd Anthony; McMillan, David William; Edmunds, Ross Montgomery; Sanchez, Eduardo

2015-03-01

Recently, a self-paced protocol demonstrated higher maximal oxygen uptake versus the traditional ramp protocol. The primary aim of the current study was to further explore potential differences in maximal oxygen uptake between the ramp and self-paced protocols using simultaneous measurement of cardiac output. Active men and women of various fitness levels (N = 30, mean age = 26.0 ± 5.0 years) completed 3 graded exercise tests separated by a minimum of 48 h. Participants initially completed progressive ramp exercise to exhaustion to determine maximal oxygen uptake followed by a verification test to confirm maximal oxygen uptake attainment. Over the next 2 sessions, they performed a self-paced and an additional ramp protocol. During exercise, gas exchange data were obtained using indirect calorimetry, and thoracic impedance was utilized to estimate hemodynamic function (stroke volume and cardiac output). One-way ANOVA with repeated measures was used to determine differences in maximal oxygen uptake and cardiac output between ramp and self-paced testing. Results demonstrated lower (p < 0.001) maximal oxygen uptake via the ramp (47.2 ± 10.2 mL·kg(-1)·min(-1)) versus the self-paced (50.2 ± 9.6 mL·kg(-1)·min(-1)) protocol, with no interaction (p = 0.06) seen for fitness level. Maximal heart rate and cardiac output (p = 0.02) were higher in the self-paced protocol versus ramp exercise. In conclusion, data show that the traditional ramp protocol may underestimate maximal oxygen uptake compared with a newly developed self-paced protocol, with a greater cardiac output potentially responsible for this outcome.

Design of a Sample Recovery Assembly for Magnetic Ramp-Wave Loading

NASA Astrophysics Data System (ADS)

Chantrenne, S.; Wise, J. L.; Asay, J. R.; Kipp, M. E.; Hall, C. A.

2009-06-01

Characterization of material behavior under dynamic loading requires studies at strain rates ranging from quasi-static to the limiting values of shock compression. For completeness, these studies involve complementary time-resolved data, which define the mechanical constitutive properties, and microstructural data, which reveal physical mechanisms underlying the observed mechanical response. Well-preserved specimens must be recovered for microstructural investigations. Magnetically generated ramp waves produce strain rates lower than those associated with shock waves, but recovery methods have been lacking for this type of loading. We adapted existing shock recovery techniques for application to magnetic ramp loading using 2-D and 3-D ALEGRA MHD code calculations to optimize the recovery design for mitigation of undesired late-time processing of the sample due to edge effects and secondary stress waves. To assess the validity of our simulations, measurements of sample deformation were compared to wavecode predictions.

Extracting Strength from Ramp-Release Experiments on Z

NASA Astrophysics Data System (ADS)

Brown, Justin

2013-06-01

Releasing from a compressed state has long been recognized as a sensitive measure of a material's constitutive response. The initial elastic unloading provides insights which can be related to changes in shear stress or, in the context of classic plasticity, to the material's yield surface. Ramp compression and subsequent release experiments on Sandia's Z machine typically consist of a driving aluminum electrode pushing a sample material which is backed by a window. A particle velocity measurement of the sample/window interface provides a ramp-release profile. Under most circumstances, however, the impedance mismatch at this interface results in the measurement of a highly perturbed velocity, particularly at the late times of interest. Wave attenuation, the finite pressure range over which the material elastically unloads, and rate effects additionally complicate the interpretation of the experiment. In an effort to accurately analyze experiments of this type, each of these complications is addressed. The wave interactions are accounted for through the so-called transfer function methodology and involves a coupling of the experimental measurements with numerical simulations. Simulated window velocity measurements are combined with the corresponding in situ simulations to define a mapping describing the wave interactions due to the presence of the window. Applying this mapping to the experimentally measured velocity results in an in situ sample response which may then be used in a classic Lagrangian analysis from which the strength can be extracted via the self-consistent method. Corrections for attenuation, pressure averaging, and limitations of the analysis due to rate-effects are verified through the use of synthetic data. To date, results on the strength of aluminum to 1.2 MBar, beryllium to 1 MBar, and tantalum to over 2 MBar have been obtained through this methodology and will be presented. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Effects of rapid shortening on rate of force regeneration and myoplasmic [Ca2+] in intact frog skeletal muscle fibres

PubMed Central

Vandenboom, R; Claflin, D R; Julian, F J

1998-01-01

The effect of rapid shortening on rate of force regeneration (dF/dtR) was examined in single, intact frog (Rana temporaria) skeletal muscle fibres (3·0 °C). Step releases leading to unloaded shortening were applied after 500 ms of stimulation, during the plateau of an isometric tetanus. Initial mean sarcomere length ranged from 2·05 to 2·35 μm; force regeneration after shortening was at 2·00 μm.Values for dF/dtR following a 25 nm half-sarcomere−1 release were 3·17 ± 0·17 (mean ± s.e.m., n= 8) times greater than the initial rate of rise of force before release (dF/dtI). As release size was increased from 25 to 175 nm half-sarcomere−1, the relationship between release size and dF/dtR decreased sharply before attaining a plateau value that was 1·34 ± 0·09 times greater than dF/dtI. Despite wide variations in dF/dtR, the velocity of unloaded shortening remained constant (2·92 ± 0·08 μm half-sarcomere−1 s−1; n= 8) for the different release amplitudes used in this study.To investigate its role in the attenuation of dF/dtR with increased shortening, the effects of rapid ramp (constant velocity) shortening on intracellular free Ca2+ concentration ([Ca2+]i) were monitored using the Ca2+-sensitive fluorescent dye furaptra. Compared with an isometric contraction, rapid fibre shortening was associated with a transient increase in [Ca2+]i while force regeneration after shortening was associated with a transient reduction in [Ca2+]i. The greatest reductions in [Ca2+]i were associated with the largest amplitude ramps.Cross-bridge-mediated modifications of the Ca2+ affinity of troponin C (TnC) may explain the fluctuations in [Ca2+]i observed during and after ramps. Associated fluctuations in TnC Ca2+ occupancy could play a role in the reduction of dF/dtR with increasing release size. PMID:9679172

Recruitment of single human low-threshold motor units with increasing loads at different muscle lengths.

PubMed

McNulty, P A; Cresswell, A G

2004-06-01

We investigated the recruitment behaviour of low threshold motor units in flexor digitorum superficialis by altering two biomechanical constraints: the load against which the muscle worked and the initial muscle length. The load was increased using isotonic (low load), loaded dynamic (intermediate load) and isometric (high load) contractions in two studies. The initial muscle position reflected resting muscle length in series A, and a longer length with digit III fully extended in series B. Intramuscular EMG was recorded from 48 single motor units in 10 experiments on five healthy subjects, 21 units in series A and 27 in series B, while subjects performed ramp up, hold and ramp down contractions. Increasing the load on the muscle decreased the force, displacement and firing rate of single motor units at recruitment at shorter muscle lengths (P<0.001, dependent t-test). At longer muscle lengths this recruitment pattern was observed between loaded dynamic and isotonic contractions, but not between isometric and loaded dynamic contractions. Thus, the recruitment properties of single motor units in human flexor digitorum superficialis are sensitive to changes in both imposed external loads and the initial length of the muscle.

Motor power factor controller with a reduced voltage starter

NASA Technical Reports Server (NTRS)

Nola, F. J. (Inventor)

1981-01-01

A power factor type motor controller is disclosed in which the conventional power factor constant voltage command signal is replaced during a starting interval with a graduated control voltage. This continuation-impart of a pending patent application (Serial No. 199, 765: Three Phase Factor Controller) provides a means for modifying the operation of the system for a motor start-up interval of 5 to 30 second. Using a ramp generators, an initial ramp-like signal replaces a constant power factor signal supplied by a potentiometer. The ramp-like signal is applied to a 15 terminal where it is summed with an operating power factor signal from phase detectors in order to obtain a control signal for ultimately controlling SCR devices. The SCR devices are turned on at an advancing rate with time responsive to the combination signal described rather than simply a function of a ramp-like signal alone.

Effect of station-specific alerting and ramp-up tones on firefighters' alarm time heart rates.

PubMed

MacNeal, James J; Cone, David C; Wistrom, Christopher L

2016-11-01

A number of long-term health effects are suffered by emergency responders, some influenced by psychological stress and fatigue. This study explored if stress and fatigue can be reduced by changing the method by which firefighters are alerted to emergency responses. Over several months, the method by which responders at a fire department were alerted was altered. Firefighter heart rates were measured first with standard alerting as a control (phase 1: all stations alerted simultaneously, with high-volume tones). The department then implemented station-specific (phase 2) and gradual volume ramp-up (phase 3) tone alerting, and heart rate increases were compared. The Fatigue Severity Score was used to examine firefighter fatigue, and the department administered a follow-up survey on personnel preferences. Individual heart rate increases (Δbpm) ranged from 2-48 bpm. Median increases were 7 bpm (IQR 4-11 bpm) during phase 1 (72.2% of alarms Δbpm<10), 7 bpm (IQR 5-12 bpm) during phase 2 (60.7% of alarms Δbpm<10), and 5 bpm (IQR 3-8 bpm) during phase 3 (82.7% of alarms Δbpm<10). The difference in medians was lower for phases 1 and 2 than for phase 3 (p = 0.0069), and more alarms in phase 3 resulted in increases of <10 bpm than in phase 2 (p = 0.0089). The Fatigue Severity Scale showed little variability: median scores 7 in phase 1, 8 in phase 2, and 7 in phase 3. Firefighters reported a strong preference for the "ramp-up" tones, and were roughly evenly divided between preferring alerting all stations simultaneously 24/7 (40% rating this 4 or 5 on a five-point Likert scale), station-specific alerting 24/7 (47.5%), or all stations during the day but station-specific at night (40%). Ramp-up tones were perceived as the best method to reduce stress during the day and overnight. Small but significant decreases in the amount of tachycardic response to station alerting are associated with simple alterations in alerting methods. Station-specific and ramp-up tones improve perceived working conditions for emergency responders.

Molecular and Kinetic Models for High-rate Thermal Degradation of Polyethylene

DOE PAGES

Lane, J. Matthew; Moore, Nathan W.

2018-02-01

Thermal degradation of polyethylene is studied under the extremely high rate temperature ramps expected in laser-driven and X-ray ablation experiments—from 10 10 to 10 14 K/s in isochoric, condensed phases. The molecular evolution and macroscopic state variables are extracted as a function of density from reactive molecular dynamics simulations using the ReaxFF potential. The enthalpy, dissociation onset temperature, bond evolution, and observed cross-linking are shown to be rate dependent. These results are used to parametrize a kinetic rate model for the decomposition and coalescence of hydrocarbons as a function of temperature, temperature ramp rate, and density. In conclusion, the resultsmore » are contrasted to first-order random-scission macrokinetic models often assumed for pyrolysis of linear polyethylene under ambient conditions.« less

Molecular and Kinetic Models for High-rate Thermal Degradation of Polyethylene

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

Lane, J. Matthew; Moore, Nathan W.

Thermal degradation of polyethylene is studied under the extremely high rate temperature ramps expected in laser-driven and X-ray ablation experiments—from 10 10 to 10 14 K/s in isochoric, condensed phases. The molecular evolution and macroscopic state variables are extracted as a function of density from reactive molecular dynamics simulations using the ReaxFF potential. The enthalpy, dissociation onset temperature, bond evolution, and observed cross-linking are shown to be rate dependent. These results are used to parametrize a kinetic rate model for the decomposition and coalescence of hydrocarbons as a function of temperature, temperature ramp rate, and density. In conclusion, the resultsmore » are contrasted to first-order random-scission macrokinetic models often assumed for pyrolysis of linear polyethylene under ambient conditions.« less

Time-dependence of the alpha to epsilon phase transformation in iron

DOE PAGES

Smith, R. F.; Eggert, J. H.; Swift, D. C.; ...

2013-12-11

Here, iron was ramp-compressed over timescales of 3 ≤ t(ns) ≤ 300 to study the time-dependence of the α→ε (bcc→hcp) phase transformation. Onset stresses (σ α→ε) for the transformation ~14.8-38.4 GPa were determined through laser and magnetic ramp-compression techniques where the transition strain-rate was varied between 10 6 ≤more » $$\\dot{μ}$$ α→ε(s ₋1) ≤ 5×10 8. We find σ α→ε= 10.8 + 0.55 ln($$\\dot{μ}$$ α→ε) for $$\\dot{μ}$$ α→ε < 10 6/s and σ α→ε= 1.15($$\\dot{μ}$$ α→ε) 0.18 for $$\\dot{μ}$$ α→ε > 10 6/s. This $$\\dot{μ}$$ response is quite similar to recent results on incipient plasticity in Fe suggesting that under high rate ramp compression the α→ε phase transition and plastic deformation occur through similar mechanisms, e.g., the rate limiting step for $$\\dot{μ}$$ > 10 6/s is due to phonon scattering from defects moving to relieve strain. We show that over-pressurization of equilibrium phase boundaries is a common feature exhibited under high strain-rate compression of many materials encompassing many orders of magnitude of strain-rate.« less

Analysis of stationary fuel cell dynamic ramping capabilities and ultra capacitor energy storage using high resolution demand data

NASA Astrophysics Data System (ADS)

Meacham, James R.; Jabbari, Faryar; Brouwer, Jacob; Mauzey, Josh L.; Samuelsen, G. Scott

Current high temperature fuel cell (HTFC) systems used for stationary power applications (in the 200-300 kW size range) have very limited dynamic load following capability or are simply base load devices. Considering the economics of existing electric utility rate structures, there is little incentive to increase HTFC ramping capability beyond 1 kWs -1 (0.4% s -1). However, in order to ease concerns about grid instabilities from utility companies and increase market adoption, HTFC systems will have to increase their ramping abilities, and will likely have to incorporate electrical energy storage (EES). Because batteries have low power densities and limited lifetimes in highly cyclic applications, ultra capacitors may be the EES medium of choice. The current analyses show that, because ultra capacitors have a very low energy storage density, their integration with HTFC systems may not be feasible unless the fuel cell has a ramp rate approaching 10 kWs -1 (4% s -1) when using a worst-case design analysis. This requirement for fast dynamic load response characteristics can be reduced to 1 kWs -1 by utilizing high resolution demand data to properly size ultra capacitor systems and through demand management techniques that reduce load volatility.

Global loudness of rising- and falling-intensity tones: How temporal profile characteristics shape overall judgments.

PubMed

Ponsot, Emmanuel; Susini, Patrick; Meunier, Sabine

2017-07-01

The mechanisms underlying global loudness judgments of rising- or falling-intensity tones were further investigated in two magnitude estimation experiments. By manipulating the temporal characteristics of such stimuli, it was examined whether judgments could be accounted for by an integration of their loudest portion over a certain temporal window associated to a "decay mechanism" downsizing this integration over time for falling ramps. In experiment 1, 1-kHz intensity-ramps were stretched in time between 1 and 16 s keeping their dynamics (difference between maximum and minimum levels) unchanged. While global loudness of rising tones increased up to 6 s, evaluations of falling tones increased at a weaker rate and slightly decayed between 6 and 16 s, resulting in significant differences between the two patterns. In experiment 2, ramps were stretched in time between 2 and 12 s keeping their slopes (rate of change in dB/s) unchanged. In this context, the main effect of duration became non-significant and the interaction between the two profiles remained, although the decay of falling tones was not significant. These results qualitatively support the view that the global loudness computation of intensity-ramps involves an integration of their loudest portions; the presence of a decay mechanism could, however, not be attested.

SU-G-BRB-03: Assessing the Sensitivity and False Positive Rate of the Integrated Quality Monitor (IQM) Large Area Ion Chamber to MLC Positioning Errors

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

Boehnke, E McKenzie; DeMarco, J; Steers, J

2016-06-15

Purpose: To examine both the IQM’s sensitivity and false positive rate to varying MLC errors. By balancing these two characteristics, an optimal tolerance value can be derived. Methods: An un-modified SBRT Liver IMRT plan containing 7 fields was randomly selected as a representative clinical case. The active MLC positions for all fields were perturbed randomly from a square distribution of varying width (±1mm to ±5mm). These unmodified and modified plans were measured multiple times each by the IQM (a large area ion chamber mounted to a TrueBeam linac head). Measurements were analyzed relative to the initial, unmodified measurement. IQM readingsmore » are analyzed as a function of control points. In order to examine sensitivity to errors along a field’s delivery, each measured field was divided into 5 groups of control points, and the maximum error in each group was recorded. Since the plans have known errors, we compared how well the IQM is able to differentiate between unmodified and error plans. ROC curves and logistic regression were used to analyze this, independent of thresholds. Results: A likelihood-ratio Chi-square test showed that the IQM could significantly predict whether a plan had MLC errors, with the exception of the beginning and ending control points. Upon further examination, we determined there was ramp-up occurring at the beginning of delivery. Once the linac AFC was tuned, the subsequent measurements (relative to a new baseline) showed significant (p <0.005) abilities to predict MLC errors. Using the area under the curve, we show the IQM’s ability to detect errors increases with increasing MLC error (Spearman’s Rho=0.8056, p<0.0001). The optimal IQM count thresholds from the ROC curves are ±3%, ±2%, and ±7% for the beginning, middle 3, and end segments, respectively. Conclusion: The IQM has proven to be able to detect not only MLC errors, but also differences in beam tuning (ramp-up). Partially supported by the Susan Scott Foundation.« less

Sub-micrometric surface texturing of AZ31 Mg-alloy through two-beam direct laser interference patterning with a ns-pulsed green fiber laser

NASA Astrophysics Data System (ADS)

Furlan, Valentina; Biondi, Marco; Demir, Ali Gökhan; Pariani, Giorgio; Previtali, Barbara; Bianco, Andrea

2017-11-01

Two-beam direct laser interference patterning (DLIP) is the method that employs two beams and provides control over the pattern geometry by regulating the angle between the beams and the wavelength of the beam. Despite the simplistic optical arrangement required for the method, the feasibility of sub-micrometric patterning of a surface depends on the correct manipulation of the process parameters, especially in the case of metallic materials. Magnesium alloys, from this point of view, exhibit further difficulty in processability due to low melting point and high reactivity. With biocompatibility and biodegradability features, Mg-alloy implants can take further advantage of surface structuring for tailoring the biological behaviour. In this work, a two-beam DLIP setup has been developed employing an industrial grade nanosecond-pulsed fiber laser emitting at 532 nm. The high repetition rate and ramped pulse profile provided by the laser were exploited for a more flexible control over the energy content deposited over the heat-sensitive Mg-alloy. The paper describes the strategies developed for controlling ramped laser emission at 20 kHz repetition rate. The process feasibility window was assessed within a large range of parameters. Within the feasibility window, a complete experimental plan was applied to investigate the effect of main laser process parameters on the pattern dimensions. Periodic surface structures with good definition down to 580 nm ± 20 nm spacing were successfully produced.

Identifying chronic errors at freeway loop detectors- splashover, pulse breakup, and sensitivity settings.

DOT National Transportation Integrated Search

2011-03-01

Traffic Management applications such as ramp metering, incident detection, travel time prediction, and vehicle : classification greatly depend on the accuracy of data collected from inductive loop detectors, but these data are : prone to various erro...

Capacitance-type blade-tip clearance measurement system using a dual amplifier with ramp/dc inputs and integration

NASA Technical Reports Server (NTRS)

Sarma, Garimella R.; Barranger, John P.

1992-01-01

The analysis and prototype results of a dual-amplifier circuit for measuring blade-tip clearance in turbine engines are presented. The capacitance between the blade tip and mounted capacitance electrode within a guard ring of a probe forms one of the feedback elements of an operational amplifier (op amp). The differential equation governing the circuit taking into consideration the nonideal features of the op amp was formulated and solved for two types of inputs (ramp and dc) that are of interest for the application. Under certain time-dependent constraints, it is shown that (1) with a ramp input the circuit has an output voltage proportional to the static tip clearance capacitance, and (2) with a dc input, the output is proportional to the derivative of the clearance capacitance, and subsequent integration recovers the dynamic capacitance. The technique accommodates long cable lengths and environmentally induced changes in cable and probe parameters. System implementation for both static and dynamic measurements having the same high sensitivity is also presented.

Capacitance-type blade-tip clearance measurement system using a dual amplifier with ramp/dc inputs and integration

NASA Astrophysics Data System (ADS)

Sarma, Garimella R.; Barranger, John P.

1992-10-01

The analysis and prototype results of a dual-amplifier circuit for measuring blade-tip clearance in turbine engines are presented. The capacitance between the blade tip and mounted capacitance electrode within a guard ring of a probe forms one of the feedback elements of an operational amplifier (op amp). The differential equation governing the circuit taking into consideration the nonideal features of the op amp was formulated and solved for two types of inputs (ramp and dc) that are of interest for the application. Under certain time-dependent constraints, it is shown that (1) with a ramp input the circuit has an output voltage proportional to the static tip clearance capacitance, and (2) with a dc input, the output is proportional to the derivative of the clearance capacitance, and subsequent integration recovers the dynamic capacitance. The technique accommodates long cable lengths and environmentally induced changes in cable and probe parameters. System implementation for both static and dynamic measurements having the same high sensitivity is also presented.

Shock Sensitivity of energetic materials

NASA Technical Reports Server (NTRS)

Kim, K.

1980-01-01

Viscoplastic deformation is examined as the principal source of hot energy. Some shock sensitivity data on a proposed model is explained. A hollow sphere model is used to approximate complex porous matrix of energetic materials. Two pieces of shock sensitivity data are qualitatively compared with results of the proposed model. The first is the p2 tau law. The second is the desensitization of energetic materials by a ramp wave applied stress. An approach to improve the model based on experimental observations is outlined.

Tangential blowing for control of strong normal shock - Boundary layer interactions on inlet ramps

NASA Technical Reports Server (NTRS)

Schwendemann, M. F.; Sanders, B. W.

1982-01-01

The use of tangential blowing from a row of holes in an aft facing step is found to provide good control of the ramp boundary layer, normal shock interaction on a fixed geometry inlet over a wide range of inlet mass flow ratios. Ramp Mach numbers of 1.36 and 1.96 are investigated. The blowing geometry is found to have a significant effect on system performance at the highest Mach number. The use of high-temperature air in the blowing system, however, has only a slight effect on performance. The required blowing rates are significantly high for the most severe test conditions. In addition, the required blowing coefficient is found to be proportional to the normal shock pressure rise.

Performance evaluation of the small-animal PET scanner ClairvivoPET using NEMA NU 4-2008 Standards.

PubMed

Sato, K; Shidahara, M; Watabe, H; Watanuki, S; Ishikawa, Y; Arakawa, Y; Nai, Y H; Furumoto, S; Tashiro, M; Shoji, T; Yanai, K; Gonda, K

2016-01-21

The aim of this study was to evaluate the performance of ClairvivoPET using NEMA NU4 standards. The ClairvivoPET incorporates a LYSO dual depth-of-interaction detector system with 151 mm axial field of view (FOV). Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated using NEMA NU4-2008 standards. Normal mouse imaging was also performed for 10 min after intravenous injection of (18)F(-)-NaF. Data were compared with 19 other preclinical PET scanners. Spatial resolution measured using full width at half maximum on FBP-ramp reconstructed images was 2.16 mm at radial offset 5 mm of the axial centre FOV. The maximum absolute sensitivity for a point source at the FOV centre was 8.72%. Peak noise equivalent counting rate (NECR) was 415 kcps at 14.6 MBq ml(-1). The uniformity with the image-quality phantom was 4.62%. Spillover ratios in the images of air and water filled chambers were 0.19 and 0.06, respectively. Our results were comparable with the 19 other preclinical PET scanners based on NEMA NU4 standards, with excellent sensitivity because of the large FOV. The ClairvivoPET with iterative reconstruction algorithm also provided sufficient visualization of the mouse spine. The high sensitivity and resolution of the ClairvivoPET scanner provided high quality images for preclinical studies.

Performance evaluation of the small-animal PET scanner ClairvivoPET using NEMA NU 4-2008 Standards

NASA Astrophysics Data System (ADS)

Sato, K.; Shidahara, M.; Watabe, H.; Watanuki, S.; Ishikawa, Y.; Arakawa, Y.; Nai, YH; Furumoto, S.; Tashiro, M.; Shoji, T.; Yanai, K.; Gonda, K.

2016-01-01

The aim of this study was to evaluate the performance of ClairvivoPET using NEMA NU4 standards. The ClairvivoPET incorporates a LYSO dual depth-of-interaction detector system with 151 mm axial field of view (FOV). Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated using NEMA NU4-2008 standards. Normal mouse imaging was also performed for 10min after intravenous injection of 18F(-)-NaF. Data were compared with 19 other preclinical PET scanners. Spatial resolution measured using full width at half maximum on FBP-ramp reconstructed images was 2.16 mm at radial offset 5 mm of the axial centre FOV. The maximum absolute sensitivity for a point source at the FOV centre was 8.72%. Peak noise equivalent counting rate (NECR) was 415kcps at 14.6MBq ml-1. The uniformity with the image-quality phantom was 4.62%. Spillover ratios in the images of air and water filled chambers were 0.19 and 0.06, respectively. Our results were comparable with the 19 other preclinical PET scanners based on NEMA NU4 standards, with excellent sensitivity because of the large FOV. The ClairvivoPET with iterative reconstruction algorithm also provided sufficient visualization of the mouse spine. The high sensitivity and resolution of the ClairvivoPET scanner provided high quality images for preclinical studies.

Illusion caused by vibration of muscle spindles reveals an involvement of muscle spindle inputs in regulating isometric contraction of masseter muscles.

PubMed

Tsukiboshi, Taisuke; Sato, Hajime; Tanaka, Yuto; Saito, Mitsuru; Toyoda, Hiroki; Morimoto, Toshifumi; Türker, Kemal Sitki; Maeda, Yoshinobu; Kang, Youngnam

2012-11-01

Spindle Ia afferents may be differentially involved in voluntary isometric contraction, depending on the pattern of synaptic connections in spindle reflex pathways. We investigated how isometric contraction of masseter muscles is regulated through the activity of their muscle spindles that contain the largest number of intrafusal fibers among skeletal muscle spindles by examining the effects of vibration of muscle spindles on the voluntary isometric contraction. Subjects were instructed to hold the jaw at resting position by counteracting ramp loads applied on lower molar teeth. In response to the increasing-ramp load, the root mean square (RMS) of masseter EMG activity almost linearly increased under no vibration, while displaying a steep linear increase followed by a slower increase under vibration. The regression line of the relationship between the load and RMS was significantly steeper under vibration than under no vibration, suggesting that the subjects overestimated the ramp load and excessively counteracted it as reflected in the emergence of bite pressure. In response to the decreasing-ramp load applied following the increasing one, the RMS hardly decreased under vibration unlike under no vibration, leading to a generation of bite pressure even after the offset of the negative-ramp load until the vibration was ceased. Thus the subjects overestimated the increasing rate of the load while underestimating the decreasing rate of the load, due to the vibration-induced illusion of jaw opening. These observations suggest that spindle Ia/II inputs play crucial roles both in estimating the load and in controlling the isometric contraction of masseter muscles in the jaw-closed position.

The value of improved wind power forecasting: Grid flexibility quantification, ramp capability analysis, and impacts of electricity market operation timescales

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

Wang, Qin; Wu, Hongyu; Florita, Anthony R.

The value of improving wind power forecasting accuracy at different electricity market operation timescales was analyzed by simulating the IEEE 118-bus test system as modified to emulate the generation mixes of the Midcontinent, California, and New England independent system operator balancing authority areas. The wind power forecasting improvement methodology and error analysis for the data set were elaborated. Production cost simulation was conducted on the three emulated systems with a total of 480 scenarios, considering the impacts of different generation technologies, wind penetration levels, and wind power forecasting improvement timescales. The static operational flexibility of the three systems was comparedmore » through the diversity of generation mix, the percentage of must-run baseload generators, as well as the available ramp rate and the minimum generation levels. The dynamic operational flexibility was evaluated by the real-time upward and downward ramp capacity. Simulation results show that the generation resource mix plays a crucial role in evaluating the value of improved wind power forecasting at different timescales. In addition, the changes in annual operational electricity generation costs were mostly influenced by the dominant resource in the system. Lastly, the impacts of pumped-storage resources, generation ramp rates, and system minimum generation level requirements on the value of improved wind power forecasting were also analyzed.« less

The value of improved wind power forecasting: Grid flexibility quantification, ramp capability analysis, and impacts of electricity market operation timescales

DOE PAGES

Wang, Qin; Wu, Hongyu; Florita, Anthony R.; ...

2016-11-11

The value of improving wind power forecasting accuracy at different electricity market operation timescales was analyzed by simulating the IEEE 118-bus test system as modified to emulate the generation mixes of the Midcontinent, California, and New England independent system operator balancing authority areas. The wind power forecasting improvement methodology and error analysis for the data set were elaborated. Production cost simulation was conducted on the three emulated systems with a total of 480 scenarios, considering the impacts of different generation technologies, wind penetration levels, and wind power forecasting improvement timescales. The static operational flexibility of the three systems was comparedmore » through the diversity of generation mix, the percentage of must-run baseload generators, as well as the available ramp rate and the minimum generation levels. The dynamic operational flexibility was evaluated by the real-time upward and downward ramp capacity. Simulation results show that the generation resource mix plays a crucial role in evaluating the value of improved wind power forecasting at different timescales. In addition, the changes in annual operational electricity generation costs were mostly influenced by the dominant resource in the system. Lastly, the impacts of pumped-storage resources, generation ramp rates, and system minimum generation level requirements on the value of improved wind power forecasting were also analyzed.« less

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

NASA Astrophysics Data System (ADS)

Yue, L.; Suppe, J.

2007-12-01

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

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

NASA Astrophysics Data System (ADS)

Yue, L.; Suppe, J.

2004-12-01

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

Simulation study of traffic car accidents at a single lane roundabout

NASA Astrophysics Data System (ADS)

Echab, H.; Lakouari, N.; Ez-Zahraouy, H.; Benyoussef, A.

2016-07-01

In this paper, using the Nagel-Schreckenberg model, we numerically investigate the probability Pac of entering/circulating car accidents to occur at single-lane roundabout under the expanded open boundary. The roundabout consists of N on-ramps (respectively, off-ramps). The boundary is controlled by the injecting rates α1,α2 and the extracting rate β. The simulation results show that, depending on the injecting rates, the car accidents are more likely to happen when the capacity of the rotary is set to its maximum. Moreover, we found that the large values of rotary size L and the probability of preferential Pexit are reliable to improve safety and reduce accidents. However, the usage of indicator, the increase of β and/or N provokes an increase of car accident probability.

Multiple-Frequency Ultrasonic Pulse-Echo Display System.

DTIC Science & Technology

1982-09-28

will sweep across some time interval. Adjust the ramp rate potentiometer to set this interval to exactly 10 ps. Ramp Delay None Set time base to 1.0 lis...the function keys. The table is a printout which results F.irectly from exercising Program KEE, listed in Appendix C-I. Note that "(ESC)B" refers to...flag +21 ŕ" = one-time flag (nessage is presented prior to full plot once per session) +22 time- base duration code +23 (High order digit) +24 * +25

EPA Region 1 Environmentally Sensitive Areas

EPA Pesticide Factsheets

This coverage represents polygon equivalents of environmentally sensitive areas (ESA) in EPA Region I. ESAs were developed as part of an EPA headquarters initiative based on reviews of various regulatory and guidance documents, as well as phone interviews with federal/state/local government agencies and private organizations. ESAs include, but are not limited to, wetlands, biological resources, habitats, national parks, archaeological/historic sites, natural heritage areas, tribal lands, drinking water intakes, marinas/boat ramps, wildlife areas, etc.

Study of the magnets used for a mobile isocenter carbon ion gantry.

PubMed

Moreno, Jhonnatan Osorio; Pullia, Marco G; Priano, Cristiana; Lante, Valeria; Necchi, Monica M; Savazzi, Simone

2013-07-01

A conceptual design of a mobile isocenter carbon ion gantry was carried out in the framework of the Particle Training Network for European Radiotherapy (PARTNER) and Union of Light Ion Centres in Europe (ULICE) projects. To validate the magnets used in this gantry, Finite Element Method (FEM) simulations were performed with COMSOL multiphysics; the purpose was to evaluate the magnetic field quality and the influence of additional support structures for correctors, 90° bending dipole and quadrupoles, both in dynamic and static regimes. Due to the low ramp rates, the dynamic effects do not disturb the homogeneity and the magnetic field level. The differences between the stationary field and the corresponding dynamic field after the end of the ramps are in the order of 10(-4); it implies that the magnets can be operated without significant field lag at the nominal ramp rate. However, even in static regime the magnetic length of corrector magnet decreases by 5% when the rotator mechanical structure is considered. The simulations suggest an optimization phase of the correctors in the rotator.

Study of the magnets used for a mobile isocenter carbon ion gantry

PubMed Central

Moreno, Jhonnatan Osorio; Pullia, Marco G.; Priano, Cristiana; Lante, Valeria; Necchi, Monica M.; Savazzi, Simone

2013-01-01

A conceptual design of a mobile isocenter carbon ion gantry was carried out in the framework of the Particle Training Network for European Radiotherapy (PARTNER) and Union of Light Ion Centres in Europe (ULICE) projects. To validate the magnets used in this gantry, Finite Element Method (FEM) simulations were performed with COMSOL multiphysics; the purpose was to evaluate the magnetic field quality and the influence of additional support structures for correctors, 90° bending dipole and quadrupoles, both in dynamic and static regimes. Due to the low ramp rates, the dynamic effects do not disturb the homogeneity and the magnetic field level. The differences between the stationary field and the corresponding dynamic field after the end of the ramps are in the order of 10–4; it implies that the magnets can be operated without significant field lag at the nominal ramp rate. However, even in static regime the magnetic length of corrector magnet decreases by 5% when the rotator mechanical structure is considered. The simulations suggest an optimization phase of the correctors in the rotator. PMID:23824120

Anatomy of a cyclically packaged Mesoproterozoic carbonate ramp in northern Canada

NASA Astrophysics Data System (ADS)

Sherman, A. G.; Narbonne, G. M.; James, N. P.

2001-03-01

Carbonates in the upper member of the Mesoproterozoic Victor Bay Formation are dominated by lime mud and packaged in cycles of 20-50 m. These thicknesses exceed those of classic shallowing-upward cycles by almost a factor of 10. Stratigraphic and sedimentological evidence suggests high-amplitude, high-frequency glacio-eustatic cyclicity, and thus a cool global climate ca. 1.2 Ga. The Victor Bay ramp is one of several late Proterozoic carbonate platforms where the proportions of lime mud, carbonate grains, and microbialites are more typical of younger Phanerozoic successions which followed the global waning of stromatolites. Facies distribution in the study area is compatible with deposition on a low-energy, microtidal, distally steepened ramp. Outer-ramp facies are hemipelagic lime mudstone, shale, carbonaceous rhythmite, and debrites. Mid-ramp facies are molar-tooth limestone tempestite with microspar-intraclast lags. In a marine environment where stromatolitic and oolitic facies were otherwise rare, large stromatolitic reefs developed at the mid-ramp, coeval with inner-ramp facies of microspar grainstone, intertidal dolomitic microbial laminite, and supratidal evaporitic red shale. Deep-subtidal, outer-ramp cycles occur in the southwestern part of the study area. Black dolomitic shale at the base is overlain by ribbon, nodular, and carbonaceous carbonate facies, all of which exhibit signs of synsedimentary disruption. Cycles in the northeast are shallow-subtidal and peritidal in character. Shallow-subtidal cycles consist of basal deep-water facies, and an upper layer of subtidal molar-tooth limestone tempestite interbedded with microspar calcarenite facies. Peritidal cycles are identical to shallow-subtidal cycles except that they contain a cap of dolomitic tidal-flat microbial laminite, and rarely of red shale sabkha facies or of sandy polymictic conglomerate. A transect along the wall of a valley extending 8.5 km perpendicular to depositional strike reveals progradation of inner-ramp tidal flats over outer- and mid-ramp facies during shoaling. The maximum basinward progradation of peritidal facies coincides with a zone of slope failure that may have promoted the development of the stromatolitic reefs. The sea-level history of the Victor Bay Formation is represented by three hectometre-scale sequences. An initial flooding event resulted in deposition of the lower Victor Bay shale member. Upper-member carbonate cycles were then deposited during highstand. Mid-ramp slumping was followed by late-highstand reef development. The second sequence began with development of an inner-ramp lowstand unconformity and a thick mid-ramp lowstand wedge. A second transgression promoted a more modest phase of reef development at the mid-ramp and shallow-water deposition continued inboard. A third and final transgressive episode eventually led to flooding of the backstepping ramp. Overall consistent cycle thickness and absence of truncated cycles, as well as the high rate and amount of creation of accommodation space, suggest that the periodicity and amplitude of sea-level fluctuation were relatively uniform, and point to a eustatic rather than tectonic mechanism of relative sea-level change. High-amplitude, high-frequency eustatic sea-level change is characteristic of icehouse worlds in which short-term, large-scale sea-level fluctuations accompany rapidly changing ice volumes affected by Milankovitch orbital forcing. Packaging of cyclic Upper Victor Bay carbonates therefore supports the hypothesis of a late Mesoproterozoic glacial period, as proposed by previous workers.

Numerical investigations on the characteristics of thermomagnetic instability in MgB2 bulks

NASA Astrophysics Data System (ADS)

Xia, Jing; Li, Maosheng; Zhou, Youhe

2017-07-01

This paper presents the characteristics of thermomagnetic instability in MgB2 bulks by numerically solving the macroscopic dynamics of thermomagnetic interaction governed by the coupled magnetic and heat diffusion equations in association with a modified E-J power-law relationship. The finite element method is used to discretize the system of partial differential equations. The calculated magnetization loops with flux jumps are consistent with the experimental results for MgB2 slabs bathed in a wide range of ambient temperatures. We reveal the evolution process of the thermomagnetic instability and present the distributions of the magnetic field, temperature, and current density before and after flux jumps. A 2D axisymmetric model is used to study the thermomagnetic instability in cylindrical MgB2 bulks. It is found that the number of flux jumps monotonously reduces as the ambient temperature rises and no flux jump appears when the ambient temperature exceeds a certain value. Moreover, the flux-jump phenomenon exists in a wide range of the ramp rate of the applied external field, i.e. 10-2-102 T s-1. Furthermore, the dependences of the first flux-jump field on the ambient temperature, ramp rate, and bulk thickness are investigated. The critical bulk thicknesses for stability are obtained for different ambient temperatures and sample radii. In addition, the influence of the capability of the interfacial heat transfer on the temporal response of the bulk temperature is discussed. We also find that the prediction of thermomagnetic instability is sensitive to the employment of the flux creep exponent in the simulations.

True Triaxial Experimental Study of Rockbursts Induced By Ramp and Cyclic Dynamic Disturbances

NASA Astrophysics Data System (ADS)

Su, Guoshao; Hu, Lihua; Feng, Xiating; Yan, Liubin; Zhang, Gangliang; Yan, Sizhou; Zhao, Bin; Yan, Zhaofu

2018-04-01

A modified rockburst testing system was utilized to reproduce rockbursts induced by ramp and cyclic dynamic disturbances with a low-intermediate strain rate of 2 × 10-3-5 × 10-3 s-1 in the laboratory. The experimental results show that both the ramp and cyclic dynamic disturbances play a significant role in inducing rockbursts. In the tests of rockbursts induced by a ramp dynamic disturbance, as the static stress before the dynamic disturbance increases, both the strength of specimens and the kinetic energy of the ejected fragments first increase and then decrease. In the tests of rockbursts induced by a cyclic dynamic disturbance, there exists a rockburst threshold of the static stress and the dynamic disturbance amplitude, and the kinetic energy of the ejected fragments first increases and then decreases as the cyclic dynamic disturbance frequency increases. The main differences between rockbursts induced by ramp dynamic disturbances and those induced by cyclic dynamic disturbances are as follows: the rockburst development process of the former is characterized by an impact failure feature, while that of the latter is characterized by a fatigue failure feature; the damage evolution curve of the specimen of the former has a leap-developing form with a significant catastrophic feature, while that of the latter has an inverted S-shape with a remarkable fatigue damage characteristic; the energy mechanism of the former involves the ramp dynamic disturbance giving extra elastic strain energy to rocks, while that of the latter involves the cyclic dynamic disturbance decreasing the ultimate energy storage capacity of rocks.

Chemiluminescence as a condition monitoring method for thermal aging and lifetime prediction of an HTPB elastomer.

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

Gillen, Kenneth Todd; Minier, Leanna M. G.; Celina, Mathias C.

Chemiluminescence (CL) has been applied as a condition monitoring technique to assess aging related changes in a hydroxyl-terminated-polybutadiene based polyurethane elastomer. Initial thermal aging of this polymer was conducted between 110 and 50 C. Two CL methods were applied to examine the degradative changes that had occurred in these aged samples: isothermal 'wear-out' experiments under oxygen yielding initial CL intensity and 'wear-out' time data, and temperature ramp experiments under inert conditions as a measure of previously accumulated hydroperoxides or other reactive species. The sensitivities of these CL features to prior aging exposure of the polymer were evaluated on the basismore » of qualifying this method as a quick screening technique for quantification of degradation levels. Both the techniques yielded data representing the aging trends in this material via correlation with mechanical property changes. Initial CL rates from the isothermal experiments are the most sensitive and suitable approach for documenting material changes during the early part of thermal aging.« less

Run-of-River Impoundments Can Remain Unfilled While Transporting Gravel Bedload: Numerical Modeling Results

NASA Astrophysics Data System (ADS)

Pearson, A.; Pizzuto, J. E.

2015-12-01

Previous work at run-of-river (ROR) dams in northern Delaware has shown that bedload supplied to ROR impoundments can be transported over the dam when impoundments remain unfilled. Transport is facilitated by high levels of sand in the impoundment that lowers the critical shear stresses for particle entrainment, and an inversely sloping sediment ramp connecting the impoundment bed (where the water depth is typically equal to the dam height) with the top of the dam (Pearson and Pizzuto, in press). We demonstrate with one-dimensional bed material transport modeling that bed material can move through impoundments and that equilibrium transport (i.e., a balance between supply to and export from the impoundment, with a constant bed elevation) is possible even when the bed elevation is below the top of the dam. Based on our field work and previous HEC-RAS modeling, we assess bed material transport capacity at the base of the sediment ramp (and ignore detailed processes carrying sediment up and ramp and over the dam). The hydraulics at the base of the ramp are computed using a weir equation, providing estimates of water depth, velocity, and friction, based on the discharge and sediment grain size distribution of the impoundment. Bedload transport rates are computed using the Wilcock-Crowe equation, and changes in the impoundment's bed elevation are determined by sediment continuity. Our results indicate that impoundments pass the gravel supplied from upstream with deep pools when gravel supply rate is low, gravel grain sizes are relatively small, sand supply is high, and discharge is high. Conversely, impoundments will tend to fill their pools when gravel supply rate is high, gravel grain sizes are relatively large, sand supply is low, and discharge is low. The rate of bedload supplied to an impoundment is the primary control on how fast equilibrium transport is reached, with discharge having almost no influence on the timing of equilibrium.

The effect of different exercise protocols and regression-based algorithms on the assessment of the anaerobic threshold.

PubMed

Zuniga, Jorge M; Housh, Terry J; Camic, Clayton L; Bergstrom, Haley C; Schmidt, Richard J; Johnson, Glen O

2014-09-01

The purpose of this study was to examine the effect of ramp and step incremental cycle ergometer tests on the assessment of the anaerobic threshold (AT) using 3 different computerized regression-based algorithms. Thirteen healthy adults (mean age and body mass [SD] = 23.4 [3.3] years and body mass = 71.7 [11.1] kg) visited the laboratory on separate occasions. Two-way repeated measures analyses of variance with appropriate follow-up procedures were used to analyze the data. The step protocol resulted in greater mean values across algorithms than the ramp protocol for the V[Combining Dot Above]O2 (step = 1.7 [0.6] L·min and ramp = 1.5 [0.4] L·min) and heart rate (HR) (step = 133 [21] b·min and ramp = 124 [15] b·min) at the AT. There were no significant mean differences, however, in power outputs at the AT between the step (115.2 [44.3] W) and the ramp (112.2 [31.2] W) protocols. Furthermore, there were no significant mean differences for V[Combining Dot Above]O2, HR, or power output across protocols among the 3 computerized regression-based algorithms used to estimate the AT. The current findings suggested that the protocol selection, but not the regression-based algorithms can affect the assessment of the V[Combining Dot Above]O2 and HR at the AT.

Functional relevance of G-protein-coupled-receptor-associated proteins, exemplified by receptor-activity-modifying proteins (RAMPs).

PubMed

Fischer, J A; Muff, R; Born, W

2002-08-01

The calcitonin (CT) receptor (CTR) and the CTR-like receptor (CRLR) are close relatives within the type II family of G-protein-coupled receptors, demonstrating sequence identity of 50%. Unlike the interaction between CT and CTR, receptors for the related hormones and neuropeptides amylin, CT-gene-related peptide (CGRP) and adrenomedullin (AM) require one of three accessory receptor-activity-modifying proteins (RAMPs) for ligand recognition. An amylin/CGRP receptor is revealed when CTR is co-expressed with RAMP1. When complexed with RAMP3, CTR interacts with amylin alone. CRLR, initially classed as an orphan receptor, is a CGRP receptor when co-expressed with RAMP1. The same receptor is specific for AM in the presence of RAMP2. Together with human RAMP3, CRLR defines an AM receptor, and with mouse RAMP3 it is a low-affinity CGRP/AM receptor. CTR-RAMP1, antagonized preferentially by salmon CT-(8-32) and not by CGRP-(8-37), and CRLR-RAMP1, antagonized by CGRP-(8-37), are two CGRP receptor isotypes. Thus amylin and CGRP interact specifically with heterodimeric complexes between CTR and RAMP1 or RAMP3, and CGRP and AM interact with complexes between CRLR and RAMP1, RAMP2 or RAMP3.

Mixed Linear/Square-Root Encoded Single-Slope Ramp Provides Low-Noise ADC with High Linearity for Focal Plane Arrays

NASA Technical Reports Server (NTRS)

Wrigley, Chris J.; Hancock, Bruce R.; Newton, Kenneth W.; Cunningham, Thomas J.

2013-01-01

Single-slope analog-to-digital converters (ADCs) are particularly useful for onchip digitization in focal plane arrays (FPAs) because of their inherent monotonicity, relative simplicity, and efficiency for column-parallel applications, but they are comparatively slow. Squareroot encoding can allow the number of code values to be reduced without loss of signal-to-noise ratio (SNR) by keeping the quantization noise just below the signal shot noise. This encoding can be implemented directly by using a quadratic ramp. The reduction in the number of code values can substantially increase the quantization speed. However, in an FPA, the fixed pattern noise (FPN) limits the use of small quantization steps at low signal levels. If the zero-point is adjusted so that the lowest column is onscale, the other columns, including those at the center of the distribution, will be pushed up the ramp where the quantization noise is higher. Additionally, the finite frequency response of the ramp buffer amplifier and the comparator distort the shape of the ramp, so that the effective ramp value at the time the comparator trips differs from the intended value, resulting in errors. Allowing increased settling time decreases the quantization speed, while increasing the bandwidth increases the noise. The FPN problem is solved by breaking the ramp into two portions, with some fraction of the available code values allocated to a linear ramp and the remainder to a quadratic ramp. To avoid large transients, both the value and the slope of the linear and quadratic portions should be equal where they join. The span of the linear portion must cover the minimum offset, but not necessarily the maximum, since the fraction of the pixels above the upper limit will still be correctly quantized, albeit with increased quantization noise. The required linear span, maximum signal and ratio of quantization noise to shot noise at high signal, along with the continuity requirement, determines the number of code values that must be allocated to each portion. The distortion problem is solved by using a lookup table to convert captured code values back to signal levels. The values in this table will be similar to the intended ramp value, but with a correction for the finite bandwidth effects. Continuous-time comparators are used, and their bandwidth is set below the step rate, which smoothes the ramp and reduces the noise. No settling time is needed, as would be the case for clocked comparators, but the low bandwidth enhances the distortion of the non-linear portion. This is corrected by use of a return lookup table, which differs from the one used to generate the ramp. The return lookup table is obtained by calibrating against a stepped precision DC reference. This results in a residual non-linearity well below the quantization noise. This method can also compensate for differential non-linearity (DNL) in the DAC used to generate the ramp. The use of a ramp with a combination of linear and quadratic portions for a single-slope ADC is novel. The number of steps is minimized by keeping the step size just below the photon shot noise. This in turn maximizes the speed of the conversion. High resolution is maintained by keeping small quantization steps at low signals, and noise is minimized by allowing the lowest analog bandwidth, all without increasing the quantization noise. A calibrated return lookup table allows the system to maintain excellent linearity.

Track reconstruction at LHC as a collaborative data challenge use case with RAMP

NASA Astrophysics Data System (ADS)

Amrouche, Sabrina; Braun, Nils; Calafiura, Paolo; Farrell, Steven; Gemmler, Jochen; Germain, Cécile; Gligorov, Vladimir Vava; Golling, Tobias; Gray, Heather; Guyon, Isabelle; Hushchyn, Mikhail; Innocente, Vincenzo; Kégl, Balázs; Neuhaus, Sara; Rousseau, David; Salzburger, Andreas; Ustyuzhanin, Andrei; Vlimant, Jean-Roch; Wessel, Christian; Yilmaz, Yetkin

2017-08-01

Charged particle track reconstruction is a major component of data-processing in high-energy physics experiments such as those at the Large Hadron Collider (LHC), and is foreseen to become more and more challenging with higher collision rates. A simplified two-dimensional version of the track reconstruction problem is set up on a collaborative platform, RAMP, in order for the developers to prototype and test new ideas. A small-scale competition was held during the Connecting The Dots / Intelligent Trackers 2017 (CTDWIT 2017) workshop. Despite the short time scale, a number of different approaches have been developed and compared along a single score metric, which was kept generic enough to accommodate a summarized performance in terms of both efficiency and fake rates.

Effects of selected design variables on three ramp, external compression inlet performance. [boundary layer control bypasses, and mass flow rate

NASA Technical Reports Server (NTRS)

Kamman, J. H.; Hall, C. L.

1975-01-01

Two inlet performance tests and one inlet/airframe drag test were conducted in 1969 at the NASA-Ames Research Center. The basic inlet system was two-dimensional, three ramp (overhead), external compression, with variable capture area. The data from these tests were analyzed to show the effects of selected design variables on the performance of this type of inlet system. The inlet design variables investigated include inlet bleed, bypass, operating mass flow ratio, inlet geometry, and variable capture area.

Edge Ohmic Heating Experiment on HT-6M Tokamak

NASA Astrophysics Data System (ADS)

Gao, Xiang; Fan, Shuping; Li, Jian'gang; Meng, Yuedong; Luo, Jiarong; Yin, Fuxian; Zeng, Lei; Ding, Liancheng; Lin, Bili; Zhang, Wei; Han, Yuqing; Tong, Xingde; Luo, Lanchang; Gong, Xianzu; Jiang, Jiaguang; Wu, Mingjun; Yin, Fei

1994-03-01

An improved ohmic confinement has been achieved on HT-6M tokamak after application of edge ohmic heating pulse which makes plasma current rapidly ramp up (0.4 ms) in a ramp rate of 12 Ma/s. The improved ohmic confinement phase is characterized by (a) energy and particle confinement time increase, (b) non-symmetric increased density ne, (c) reduced Hα radiation, (d) increased Te and steeper Te, ne profile at the edge. The results from soft x-ray sawteeth inversion radius and βp + li/2 implied the anomalous current penetration.

A new atomic force microscope force ramp technique using digital force feedback control reveals mechanically weak protein unfolding events.

PubMed

Kawakami, M; Smith, D A

2008-12-10

We have developed a new force ramp modification of the atomic force microscope (AFM) which can control multiple unfolding events of a multi-modular protein using software-based digital force feedback control. With this feedback the force loading rate can be kept constant regardless the length of soft elastic linkage or number of unfolded polypeptide domains. An unfolding event is detected as a sudden drop in force, immediately after which the feedback control reduces the applied force to a low value of a few pN by lowering the force set point. Hence the remaining folded domains can relax and the subsequent force ramp is applied to relaxed protein domains identically in each case. We have applied this technique to determine the kinetic parameters x(u), which is the distance between the native state and transition state, and α(0), which is the unfolding rate constant at zero force, for the mechanical unfolding of a pentamer of I27 domains of titin. In each force ramp the unfolding probability depends on the number of folded domains remaining in the system and we had to take account of this effect in the analysis of unfolding force data. We obtained values of x(u) and α(0) to be 0.28 nm and 1.02 × 10(-3) s(-1), which are in good agreement with those obtained from conventional constant velocity experiments. This method reveals unfolding data at low forces that are not seen in constant velocity experiments and corrects for the change in stiffness that occurs with most mechanical systems throughout the unfolding process to allow constant force ramp experiments to be carried out. In addition, a mechanically weak structure was detected, which formed from the fully extended polypeptide chain during a force quench. This indicates that the new technique will allow studies of the folding kinetics of previously hidden, mechanically weak species.

The effects of taurine on repeat sprint cycling after low or high cadence exhaustive exercise in females.

PubMed

Waldron, Mark; Knight, Francesca; Tallent, Jamie; Patterson, Stephen; Jeffries, Owen

2018-06-01

This study investigated the effects of taurine on repeated sprint exercise, performed after fixed incremental ramp exercise to exhaustion at isokinetic high (90 r/min) or low (50 r/min) cadences. In a double-blind, repeated measures design, nine females completed an incremental ramp test to volitional exhaustion, followed by 2 min active recovery and 6 × 10 s sprints on a cycle ergometer, in one of four conditions: high cadence (90 r/min) + taurine (50 mg/kg body mass); high cadence + placebo (3 mg/kg body mass maltodextrin); low cadence (50 r/min) + taurine; low cadence + placebo. Heart rate (HR) and blood lactate concentration B[La] were measured before and after the ramp test and after the sprints. Taurine lowered HR vs. placebo prior to the ramp test (P = 0.004; d = 2.1). There was an effect of condition on ramp performance (P < 0.001), with higher end-test power (d = 3.7) in taurine conditions. During repeated sprints, there was a condition × time interaction (P = 0.002), with higher peak sprint power in the placebo conditions compared to taurine (sprint 2-6; P < 0.05). B[La] was higher in taurine compared to placebo post-ramp (P = 0.004; d = 4.7). Taurine-lowered pre-exercise HR and improved incremental end-test power output, with subsequent detrimental effects on sprint performance, independent of cadence. Short endurance performance can be acutely enhanced after taurine ingestion but this effect might not be maintained across longer periods of exercise or induce the need for longer recovery periods.

Vortex Generators to Control Boundary Layer Interactions

NASA Technical Reports Server (NTRS)

Babinsky, Holger (Inventor); Loth, Eric (Inventor); Lee, Sang (Inventor)

2014-01-01

Devices for generating streamwise vorticity in a boundary includes various forms of vortex generators. One form of a split-ramp vortex generator includes a first ramp element and a second ramp element with front ends and back ends, ramp surfaces extending between the front ends and the back ends, and vertical surfaces extending between the front ends and the back ends adjacent the ramp surfaces. A flow channel is between the first ramp element and the second ramp element. The back ends of the ramp elements have a height greater than a height of the front ends, and the front ends of the ramp elements have a width greater than a width of the back ends.

Using Divertor Strike Point Splitting to Study Plasma Response and Its Sensitivity to Equilibrium Uncertainties

NASA Astrophysics Data System (ADS)

Teklu, Abraham; Orlov, D. M.; Moyer, R. A.; Bykov, I.; Evans, T. E.; Wu, W.; Trevisan, G. L.; Lyons, B. C.; Abrams, T.; Makowski, M. A.; Lasnier, C. S.; Fenstermacher, M. E.

2017-10-01

Resonant magnetic perturbations (RMPs) from 3D coils have been varied to modify the splitting of the divertor strike points in DIII-D. This splitting is imaged in filtered visible and infrared emission from the divertor to determine the particle and heat flux patterns on the target plates. The observed splitting is compared to vacuum and plasma response modeling in discharges where a subset of the RMP coils were ramped to shift the divertor footprints from dominantly n = 3 to n = 2 pattern. These results will be used to determine if the plasma response model can be validated with the measured splitting. We will also study the sensitivity of the modeled splitting to details of the 2D equilibrium. This RMP ramp technique could be used in ITER to spread out the heat flux while avoiding excessive forces on the RMP coils. Work supported by U.S. DOE under the Science Undergraduate Laboratory Internship (SULI) program and DE-FC02-04ER54698, DE-FG02-07ER54917, DE-FG02-05ER54809 and DE-AC52-07NA27344.

Quasi-Steady Evolution of Hillslopes in Layered Landscapes: An Analytic Approach

NASA Astrophysics Data System (ADS)

Glade, R. C.; Anderson, R. S.

2018-01-01

Landscapes developed in layered sedimentary or igneous rocks are common on Earth, as well as on other planets. Features such as hogbacks, exposed dikes, escarpments, and mesas exhibit resistant rock layers adjoining more erodible rock in tilted, vertical, or horizontal orientations. Hillslopes developed in the erodible rock are typically characterized by steep, linear-to-concave slopes or "ramps" mantled with material derived from the resistant layers, often in the form of large blocks. Previous work on hogbacks has shown that feedbacks between weathering and transport of the blocks and underlying soft rock can create relief over time and lead to the development of concave-up slope profiles in the absence of rilling processes. Here we employ an analytic approach, informed by numerical modeling and field data, to describe the quasi-steady state behavior of such rocky hillslopes for the full spectrum of resistant layer dip angles. We begin with a simple geometric analysis that relates structural dip to erosion rates. We then explore the mechanisms by which our numerical model of hogback evolution self-organizes to meet these geometric expectations, including adjustment of soil depth, erosion rates, and block velocities along the ramp. Analytical solutions relate easily measurable field quantities such as ramp length, slope, block size, and resistant layer dip angle to local incision rate, block velocity, and block weathering rate. These equations provide a framework for exploring the evolution of layered landscapes and pinpoint the processes for which we require a more thorough understanding to predict their evolution over time.

Receptor activity-modifying protein-dependent effects of mutations in the calcitonin receptor-like receptor: implications for adrenomedullin and calcitonin gene-related peptide pharmacology

PubMed Central

Watkins, H A; Walker, C S; Ly, K N; Bailey, R J; Barwell, J; Poyner, D R; Hay, D L

2014-01-01

Background and Purpose Receptor activity-modifying proteins (RAMPs) define the pharmacology of the calcitonin receptor-like receptor (CLR). The interactions of the different RAMPs with this class B GPCR yield high-affinity calcitonin gene-related peptide (CGRP) or adrenomedullin (AM) receptors. However, the mechanism for this is unclear. Experimental Approach Guided by receptor models, we mutated residues in the N-terminal helix of CLR, RAMP2 and RAMP3 hypothesized to be involved in peptide interactions. These were assayed for cAMP production with AM, AM2 and CGRP together with their cell surface expression. Binding studies were also conducted for selected mutants. Key Results An important domain for peptide interactions on CLR from I32 to I52 was defined. Although I41 was universally important for binding and receptor function, the role of other residues depended on both ligand and RAMP. Peptide binding to CLR/RAMP3 involved a more restricted range of residues than that to CLR/RAMP1 or CLR/RAMP2. E101 of RAMP2 had a major role in AM interactions, and F111/W84 of RAMP2/3 was important with each peptide. Conclusions and Implications RAMP-dependent effects of CLR mutations suggest that the different RAMPs control accessibility of peptides to binding residues situated on the CLR N-terminus. RAMP3 appears to alter the role of specific residues at the CLR-RAMP interface compared with RAMP1 and RAMP2. PMID:24199627

Evaluation of a fuzzy logic ramp metering algorithm : a comparative study among three ramp metering algorithms used in the greater Seattle area

DOT National Transportation Integrated Search

2000-02-01

A Fuzzy Logic Ramp Metering Algorithm was implemented on 126 ramps in the greater Seattle area. Two multiple-ramp study sites were evaluted by comparing the fuzzy logic controller (FLC) to the other two ramp metering algorithms in operation at those ...

Membrane potential dynamics of grid cells

PubMed Central

Domnisoru, Cristina; Kinkhabwala, Amina A.; Tank, David W.

2014-01-01

During navigation, grid cells increase their spike rates in firing fields arranged on a strikingly regular triangular lattice, while their spike timing is often modulated by theta oscillations. Oscillatory interference models of grid cells predict theta amplitude modulations of membrane potential during firing field traversals, while competing attractor network models predict slow depolarizing ramps. Here, using in-vivo whole-cell recordings, we tested these models by directly measuring grid cell intracellular potentials in mice running along linear tracks in virtual reality. Grid cells had large and reproducible ramps of membrane potential depolarization that were the characteristic signature tightly correlated with firing fields. Grid cells also exhibited intracellular theta oscillations that influenced their spike timing. However, the properties of theta amplitude modulations were not consistent with the view that they determine firing field locations. Our results support cellular and network mechanisms in which grid fields are produced by slow ramps, as in attractor models, while theta oscillations control spike timing. PMID:23395984

The Tool Life of Ball Nose end Mill Depending on the Different Types of Ramping

NASA Astrophysics Data System (ADS)

Vopát, Tomáš; Peterka, Jozef; Kováč, Martin

2014-12-01

The article deals with the cutting tool wear measurement process and tool life of ball nose end mill depending on upward ramping and downward ramping. The aim was to determine and compare the wear (tool life) of ball nose end mill for different types of copy milling operations, as well as to specify particular steps of the measurement process. In addition, we examined and observed cutter contact areas of ball nose end mill with machined material. For tool life test, DMG DMU 85 monoBLOCK 5-axis CNC milling machine was used. In the experiment, cutting speed, feed rate, axial depth of cut and radial depth of cut were not changed. The cutting tool wear was measured on Zoller Genius 3s universal measuring machine. The results show different tool life of ball nose end mills depending on the copy milling strategy.

Numerical optimization of actuator trajectories for ITER hybrid scenario profile evolution

NASA Astrophysics Data System (ADS)

van Dongen, J.; Felici, F.; Hogeweij, G. M. D.; Geelen, P.; Maljaars, E.

2014-12-01

Optimal actuator trajectories for an ITER hybrid scenario ramp-up are computed using a numerical optimization method. For both L-mode and H-mode scenarios, the time trajectory of plasma current, EC heating and current drive distribution is determined that minimizes a chosen cost function, while satisfying constraints. The cost function is formulated to reflect two desired properties of the plasma q profile at the end of the ramp-up. The first objective is to maximize the ITG turbulence threshold by maximizing the volume-averaged s/q ratio. The second objective is to achieve a stationary q profile by having a flat loop voltage profile. Actuator and physics-derived constraints are included, imposing limits on plasma current, ramp rates, internal inductance and q profile. This numerical method uses the fast control-oriented plasma profile evolution code RAPTOR, which is successfully benchmarked against more complete CRONOS simulations for L-mode and H-mode mode ITER hybrid scenarios. It is shown that the optimized trajectories computed using RAPTOR also result in an improved ramp-up scenario for CRONOS simulations using the same input trajectories. Furthermore, the optimal trajectories are shown to vary depending on the precise timing of the L-H transition.

A driving simulator study of driver performance on deceleration lanes.

PubMed

Calvi, A; Benedetto, A; De Blasiis, M R

2012-03-01

Deceleration lanes are important because they help drivers transition from high-speed lanes to low-speed ramps. Although they are designed to allow vehicles to depart the freeway safely and efficiently, many studies report high accident rates on exit ramps with the highest percentage of crashes taking place in deceleration lanes. This paper describes the results of a driving simulator study that focused on driving performance while approaching a divergence area and decelerating during the exiting maneuver. Three different traffic scenarios were simulated to analyze the influence of traffic volume on driving performance. Thirty drivers drove in the simulator in these scenarios while data on their lateral position, speed and deceleration were collected. Our results indicate there are considerable differences between the main assumptions of models generally used to design deceleration lanes and actual driving performance. In particular, diverging drivers begin to decelerate before arriving at the deceleration lane, causing interference with the main flow. Moreover, speeds recorded at the end of the deceleration lane exceed those for which the ramp's curves are designed; this creates risky driving conditions that could explain the high crash rates found in studies of exit ramps. Finally, statistical analyses demonstrate significant influences of traffic volume on some aspects of exiting drivers' performance: lower traffic volume results in elevated exiting speed and deceleration, and diverging drivers begin to decelerate earlier along the main lane when traffic volume is low. However, speeds at the end of the deceleration lane and the site of lane changing are not significantly influenced by traffic volume. Copyright © 2011 Elsevier Ltd. All rights reserved.

Understanding Micro-Ramp Control for Shock Boundary Layer Interactions

DTIC Science & Technology

2008-02-07

micro-ramps on a supersonic boundary layer at M=3.0 was investigated using monotone integrated Large Eddy Simulations (MILES) and Reynolds Averaged Navier... Supersonic boundary layer flow with micro-ramp and no shock wave 3.2 SBLI with no micro-ramp 3.3 SBLI with micro-ramp 3.4 Micro-ramp size and location IV . C...ramps on a supersonic boundary layer at M=3.0 was investigated using monotone integrated Large Eddy Simulations (MILES) and Reynolds Averaged Navier

Locomotor Behavior of Chickens Anticipating Incline Walking

PubMed Central

LeBlanc, Chantal; Tobalske, Bret; Szkotnicki, Bill; Harlander-Matauschek, Alexandra

2018-01-01

Keel bone damage (KBD) is prevalent in hens raised for egg production, and ramps between different tiers in aviaries have potential to reduce the frequency of falls resulting in KBD. Effective use of ramps requires modulation of locomotion in anticipation of the incline. Inadequate adaptive locomotion may be one explanation why domestic layer hens (Gallus gallus domesticus) exhibit high rates of KBD. To improve understanding of the capacity of hens to modulate their locomotion in anticipation of climbing, we measured the effects of incline angle upon the mechanics of the preparatory step before ascending a ramp. Because the energetic challenge of climbing increases with slope, we predicted that as angle of incline increased, birds during foot contact with the ground before starting to climb would increase their peak force and duration of contact and reduce variation in center of pressure (COP) under their foot. We tested 20 female domestic chickens on ramp inclines at slopes of +0°, +40°, and +70° when birds were 17, 21, 26, 31, and 36 weeks of age. There were significantly higher vertical peak ground reaction forces in preparation at the steepest slope, and ground contact time increased significantly with each increase in ramp angle. Effects upon variation in COP were not apparent; likewise, effects of limb length, age, body mass were not significant. Our results reveal that domestic chickens are capable of modulating their locomotion in response to incline angle. PMID:29376060

Three-Dimensional Printable High-Temperature and High-Rate Heaters.

PubMed

Yao, Yonggang; Fu, Kun Kelvin; Yan, Chaoyi; Dai, Jiaqi; Chen, Yanan; Wang, Yibo; Zhang, Bilun; Hitz, Emily; Hu, Liangbing

2016-05-24

High temperature heaters are ubiquitously used in materials synthesis and device processing. In this work, we developed three-dimensional (3D) printed reduced graphene oxide (RGO)-based heaters to function as high-performance thermal supply with high temperature and ultrafast heating rate. Compared with other heating sources, such as furnace, laser, and infrared radiation, the 3D printed heaters demonstrated in this work have the following distinct advantages: (1) the RGO based heater can operate at high temperature up to 3000 K because of using the high temperature-sustainable carbon material; (2) the heater temperature can be ramped up and down with extremely fast rates, up to ∼20 000 K/second; (3) heaters with different shapes can be directly printed with small sizes and onto different substrates to enable heating anywhere. The 3D printable RGO heaters can be applied to a wide range of nanomanufacturing when precise temperature control in time, placement, and the ramping rate are important.

Optimization of hetero-epitaxial growth for the threading dislocation density reduction of germanium epilayers

NASA Astrophysics Data System (ADS)

Chong, Haining; Wang, Zhewei; Chen, Chaonan; Xu, Zemin; Wu, Ke; Wu, Lan; Xu, Bo; Ye, Hui

2018-04-01

In order to suppress dislocation generation, we develop a "three-step growth" method to heteroepitaxy low dislocation density germanium (Ge) layers on silicon with the MBE process. The method is composed of 3 growth steps: low temperature (LT) seed layer, LT-HT intermediate layer as well as high temperature (HT) epilayer, successively. Threading dislocation density (TDD) of epitaxial Ge layers is measured as low as 1.4 × 106 cm-2 by optimizing the growth parameters. The results of Raman spectrum showed that the internal strain of heteroepitaxial Ge layers is tensile and homogeneous. During the growth of LT-HT intermediate layer, TDD reduction can be obtained by lowering the temperature ramping rate, and high rate deposition maintains smooth surface morphology in Ge epilayer. A mechanism based on thermodynamics is used to explain the TDD and surface morphological dependence on temperature ramping rate and deposition rate. Furthermore, we demonstrate that the Ge layer obtained can provide an excellent platform for III-V materials integrated on Si.

Annealing to optimize the primary drying rate, reduce freezing-induced drying rate heterogeneity, and determine T(g)' in pharmaceutical lyophilization.

PubMed

Searles, J A; Carpenter, J F; Randolph, T W

2001-07-01

In a companion paper we show that the freezing of samples in vials by shelf-ramp freezing results in significant primary drying rate heterogeneity because of a dependence of the ice crystal size on the nucleation temperature during freezing.1 The purpose of this study was to test the hypothesis that post-freezing annealing, in which the product is held at a predetermined temperature for a specified duration, can reduce freezing-induced heterogeneity in sublimation rates. In addition, we test the impact of annealing on primary drying rates. Finally, we use the kinetics of relaxations during annealing to provide a simple measurement of T(g)', the glass transition temperature of the maximally freeze-concentrated amorphous phase, under conditions and time scales most appropriate for industrial lyophilization cycles. Aqueous solutions of hydroxyethyl starch (HES), sucrose, and HES:sucrose were either frozen by placement on a shelf while the temperature was reduced ("shelf-ramp frozen") or by immersion into liquid nitrogen. Samples were then annealed for various durations over a range of temperatures and partially lyophilized to determine the primary drying rate. The morphology of fully dried liquid nitrogen-frozen samples was examined using scanning electron microscopy. Annealing reduced primary drying rate heterogeneity for shelf-ramp frozen samples, and resulted in up to 3.5-fold increases in the primary drying rate. These effects were due to increased ice crystal sizes, simplified amorphous structures, and larger and more numerous holes on the cake surface of annealed samples. Annealed HES samples dissolved slightly faster than their unannealed counterparts. Annealing below T(g)' did not result in increased drying rates. We present a simple new annealing-lyophilization method of T(g)' determination that exploits this phenomenon. It can be carried out with a balance and a freeze-dryer, and has the additional advantage that a large number of candidate formulations can be evaluated simultaneously.

Structure-function analysis of amino acid 74 of human RAMP1 and RAMP3 and its role in peptide interactions with adrenomedullin and calcitonin gene-related peptide receptors.

PubMed

Qi, Tao; Ly, Kien; Poyner, David R; Christopoulos, George; Sexton, Patrick M; Hay, Debbie L

2011-05-01

The receptors for calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) are complexes of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying proteins (RAMP). The CGRP receptor is a CLR/RAMP1 pairing whereas CLR/RAMP2 and CLR/RAMP3 constitute two subtypes of AM receptor: AM(1) and AM(2), respectively. Previous studies identified Glu74 in RAMP3 to be important for AM binding and potency. To further understand the importance of this residue and its equivalent in RAMP1 (Trp74) we substituted the native amino acids with several others. In RAMP3, these were Trp, Phe, Tyr, Ala, Ser, Thr, Arg and Asn; in RAMP1, Glu, Phe, Tyr, Ala and Asn substitutions were made. The mutant RAMPs were co-expressed with CLR in Cos7 cells; receptor function in response to AM, AM(2)/intermedin and CGRP was measured in a cAMP assay and cell surface expression was determined by ELISA. Phe reduced AM potency in RAMP3 but had no effect in RAMP1. In contrast, Tyr had no effect in RAMP3 but enhanced AM potency in RAMP1. Most other substitutions had a small effect on AM potency in both receptors whereas there was little impact on CGRP or AM(2) potency. Overall, these data suggest that the geometry and charge of the residue at position 74 contribute to how AM interacts with the AM(2) and CGRP receptors and confirms the role of this position in dictating differential AM pharmacology at the AM(2) and CGRP receptors. Copyright © 2011. Published by Elsevier Inc.

Implications of sea-level rise in a modern carbonate ramp setting

NASA Astrophysics Data System (ADS)

Lokier, Stephen W.; Court, Wesley M.; Onuma, Takumi; Paul, Andreas

2018-03-01

This study addresses a gap in our understanding of the effects of sea-level rise on the sedimentary systems and morphological development of recent and ancient carbonate ramp settings. Many ancient carbonate sequences are interpreted as having been deposited in carbonate ramp settings. These settings are poorly-represented in the Recent. The study documents the present-day transgressive flooding of the Abu Dhabi coastline at the southern shoreline of the Arabian/Persian Gulf, a carbonate ramp depositional system that is widely employed as a Recent analogue for numerous ancient carbonate systems. Fourteen years of field-based observations are integrated with historical and recent high-resolution satellite imagery in order to document and assess the onset of flooding. Predicted rates of transgression (i.e. landward movement of the shoreline) of 2.5 m yr- 1 (± 0.2 m yr- 1) based on global sea-level rise alone were far exceeded by the flooding rate calculated from the back-stepping of coastal features (10-29 m yr- 1). This discrepancy results from the dynamic nature of the flooding with increased water depth exposing the coastline to increased erosion and, thereby, enhancing back-stepping. A non-accretionary transgressive shoreline trajectory results from relatively rapid sea-level rise coupled with a low-angle ramp geometry and a paucity of sediments. The flooding is represented by the landward migration of facies belts, a range of erosive features and the onset of bioturbation. Employing Intergovernmental Panel on Climate Change (Church et al., 2013) predictions for 21st century sea-level rise, and allowing for the post-flooding lag time that is typical for the start-up of carbonate factories, it is calculated that the coastline will continue to retrograde for the foreseeable future. Total passive flooding (without considering feedback in the modification of the shoreline) by the year 2100 is calculated to likely be between 340 and 571 m with a flooding rate of 3.40-8.64 m yr- 1. However, adopting the observation that global sea-level rise only accounts for 15% of the recorded shoreline retreat, this figure rises dramatically to a total likely dynamic flooding (considering modifications to the shoreline) of between 2.3 and 3.8 km. Loss of microbial and mangal habitats will subject the exposed shoreline to increasing erosion. Shoreline retreat will threaten existing coastal infrastructure.

Phase transition of a new lattice hydrodynamic model with consideration of on-ramp and off-ramp

NASA Astrophysics Data System (ADS)

Zhang, Geng; Sun, Di-hua; Zhao, Min

2018-01-01

A new traffic lattice hydrodynamic model with consideration of on-ramp and off-ramp is proposed in this paper. The influence of on-ramp and off-ramp on the stability of the main road is uncovered by theoretical analysis and computer simulation. Through linear stability theory, the neutral stability condition of the new model is obtained and the results show that the unstable region in the phase diagram is enlarged by considering the on-ramp effect but shrunk with consideration of the off-ramp effect. The mKdV equation near the critical point is derived via nonlinear reductive perturbation method and the occurrence of traffic jamming transition can be described by the kink-antikink soliton solution of the mKdV equation. From the simulation results of space-time evolution of traffic density waves, it is shown that the on-ramp can worsen the traffic stability of the main road but off-ramp is positive in stabilizing the traffic flow of the main road.

Characterizing and analyzing ramping events in wind power, solar power, load, and netload

DOE PAGES

Cui, Mingjian; Zhang, Jie; Feng, Cong; ...

2017-04-07

Here, one of the biggest concerns associated with integrating a large amount of renewable energy into the power grid is the ability to handle large ramps in the renewable power output. For the sake of system reliability and economics, it is essential for power system operators to better understand the ramping features of renewable, load, and netload. An optimized swinging door algorithm (OpSDA) is used and extended to accurately and efficiently detect ramping events. For wind power ramps detection, a process of merging 'bumps' (that have a different changing direction) into adjacent ramping segments is included to improve the performancemore » of the OpSDA method. For solar ramps detection, ramping events that occur in both clear-sky and measured (or forecasted) solar power are removed to account for the diurnal pattern of solar generation. Ramping features are extracted and extensively compared between load and netload under different renewable penetration levels (9.77%, 15.85%, and 51.38%). Comparison results show that (i) netload ramp events with shorter durations and smaller magnitudes occur more frequently when renewable penetration level increases, and the total number of ramping events also increases; and (ii) different ramping characteristics are observed in load and netload even with a low renewable penetration level.« less

Forward masking of dynamic acoustic intensity: effects of intensity region and end-level.

PubMed

Olsen, Kirk N; Stevens, Catherine J

2012-01-01

Overestimation of loudness change typically occurs in response to up-ramp auditory stimuli (increasing intensity) relative to down-ramps (decreasing intensity) matched on frequency, duration, and end-level. In the experiment reported, forward masking is used to investigate a sensory component of up-ramp overestimation: persistence of excitation after stimulus presentation. White-noise and synthetic vowel 3.6 s up-ramp and down-ramp maskers were presented over two regions of intensity change (40-60 dB SPL, 60-80 dB SPL). Three participants detected 10 ms 1.5 kHz pure tone signals presented at masker-offset to signal-offset delays of 10, 20, 30, 50, 90, 170 ms. Masking magnitude was significantly greater in response to up-ramps compared with down-ramps for masker-signal delays up to and including 50 ms. When controlling for an end-level recency bias (40-60 dB SPL up-ramp vs 80-60 dB SPL down-ramp), the difference in masking magnitude between up-ramps and down-ramps was not significant at each masker-signal delay. Greater sensory persistence in response to up-ramps is argued to have minimal effect on perceptual overestimation of loudness change when response biases are controlled. An explanation based on sensory adaptation is discussed.

Growth of analog Al(x)Ga(1-x)As/GaAs parabolic quantum wells by molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Wang, S. M.; Treideris, G.; Chen, W. Q.; Andersson, T. G.

1993-01-01

Parabolic Al(x)Ga(1-x)As/GaAs quantum wells have been grown by molecular beam epitaxy with linear ramping of the Al effusion cell temperature, where the ramping rate was carefully analyzed to avoid a flux lag. The calculated potential profile from the temperature variation was very close to the parabolic one. Low-temperature photoluminescence showed clear interband transitions up to the n = 3 sublevels. The equal energy spacing between adjacent transitions involving heavy-hole states confirmed the parabolic shape of the quantum well.

Integrated database and analysis system for the evaluation of freeway corridors for potential ramp signaling : [summary].

DOT National Transportation Integrated Search

2011-01-01

Ramp signaling is the installation of traffic signals on freeway on-ramps. Studies have shown that in many locations, ramp signaling helped alleviate traffic congestion and improve safety. However, not all freeway locations are suitable for ramp sign...

Rock ramp design guidelines

USGS Publications Warehouse

Mooney, David M.; Holmquist-Johnson, Christopher L.; Broderick, Susan

2007-01-01

Rock ramps or roughened channels consist of steep reaches stabilized by large immobile material (riprap). Primary objectives for rock ramps include: Create adequate head for diversionMaintain fish passage during low-flow conditionsMaintain hydraulic conveyance during high-flow conditionsSecondary objectives for rock ramp design include:Emulate natural systemsMinimize costsThe rock ramp consists of a low-flow channel designed to maintain biologically adequate depth and velocity conditions during periods of small discharges. The remainder of the ramp is designed to withstand and pass large flows with minimal structural damage. The following chapters outline a process for designing rock ramps.

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

Cui, Mingjian; Zhang, Jie; Feng, Cong

Here, one of the biggest concerns associated with integrating a large amount of renewable energy into the power grid is the ability to handle large ramps in the renewable power output. For the sake of system reliability and economics, it is essential for power system operators to better understand the ramping features of renewable, load, and netload. An optimized swinging door algorithm (OpSDA) is used and extended to accurately and efficiently detect ramping events. For wind power ramps detection, a process of merging 'bumps' (that have a different changing direction) into adjacent ramping segments is included to improve the performancemore » of the OpSDA method. For solar ramps detection, ramping events that occur in both clear-sky and measured (or forecasted) solar power are removed to account for the diurnal pattern of solar generation. Ramping features are extracted and extensively compared between load and netload under different renewable penetration levels (9.77%, 15.85%, and 51.38%). Comparison results show that (i) netload ramp events with shorter durations and smaller magnitudes occur more frequently when renewable penetration level increases, and the total number of ramping events also increases; and (ii) different ramping characteristics are observed in load and netload even with a low renewable penetration level.« less

Discharge properties of abductor hallucis before, during, and after an isometric fatigue task.

PubMed

Kelly, Luke A; Racinais, Sebastien; Cresswell, Andrew G

2013-08-01

Abductor hallucis is the largest muscle in the arch of the human foot and comprises few motor units relative to its physiological cross-sectional area. It has been described as a postural muscle, aiding in the stabilization of the longitudinal arch during stance and gait. The purpose of this study was to describe the discharge properties of abductor hallucis motor units during ramp and hold isometric contractions, as well as its discharge characteristics during fatigue. Intramuscular electromyographic recordings from abductor hallucis were made in 5 subjects; from those recordings, 42 single motor units were decomposed. Data were recorded during isometric ramp contractions at 60% maximum voluntary contraction (MVC), performed before and after a submaximal isometric contraction to failure (mean force 41.3 ± 15.3% MVC, mean duration 233 ± 116 s). Motor unit recruitment thresholds ranged from 10.3 to 54.2% MVC. No significant difference was observed between recruitment and derecruitment thresholds or their respective discharge rates for both the initial and postfatigue ramp contractions (all P > 0.25). Recruitment threshold was positively correlated with recruitment discharge rate (r = 0.47, P < 0.03). All motor units attained similar peak discharge rates (14.0 ± 0.25 pulses/s) and were not correlated with recruitment threshold. Thirteen motor units could be followed during the isometric fatigue task, with a decline in discharge rate and increase in discharge rate variability occurring in the final 25% of the task (both P < 0.05). We have shown that abductor hallucis motor units discharge relatively slowly and are considerably resistant to fatigue. These characteristics may be effective for generating and sustaining the substantial level of force that is required to stabilize the longitudinal arch during weight bearing.

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

NASA Astrophysics Data System (ADS)

Maillot, B.; Leroy, Y.

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

OH PLIF Visualization of the UVa Supersonic Combustion Experiment: Configuration C

NASA Technical Reports Server (NTRS)

McRae, Colin D.; Johansen, Craig T.; Danehy, Paul M.; Gallo, Emanuela C. A.; Cantu, Luca M. L.; Magnotti, Gaetano; Cutler, Andrew D.; Rockwell, Robert D., Jr.; Goyne, Christopher P.; McDnaiel, James C.

2013-01-01

Non-intrusive hydroxyl radical (OH) planar laser-induced fluorescence (PLIF) measurements were obtained in configuration C of the University of Virginia supersonic combustion experiment. The combustion of hydrogen fuel injected through an unswept compression ramp into a supersonic cross-flow was imaged over a range of streamwise positions. Images were corrected for optical distortion, variations in the laser sheet profile, and different camera views. Results indicate an effect of fuel equivalence ratio on combustion zone shape and local turbulence length scale. The streamwise location of the reaction zone relative to the fuel injector was also found to be sensitive to the fuel equivalence ratio. The flow boundary conditions in the combustor section, which are sensitive to the fuel flow rate, are believed to have caused this effect. A combination of laser absorption and radiative trapping effects are proposed to have caused asymmetry observed in the images. The results complement previously published OH PLIF data obtained for configuration A along with other non-intrusive measurements to form a database for computational fluid dynamics (CFD) model validation.

Base Heating Sensitivity Study for a 4-Cluster Rocket Motor Configuration in Supersonic Freestream

NASA Technical Reports Server (NTRS)

Mehta, Manish; Canabal, Francisco; Tashakkor, Scott B.; Smith, Sheldon D.

2011-01-01

In support of launch vehicle base heating and pressure prediction efforts using the Loci-CHEM Navier-Stokes computational fluid dynamics solver, 35 numerical simulations of the NASA TND-1093 wind tunnel test have been modeled and analyzed. This test article is composed of four JP-4/LOX 500 lbf rocket motors exhausting into a Mach 2 - 3.5 wind tunnel at various ambient pressure conditions. These water-cooled motors are attached to a base plate of a standard missile forebody. We explore the base heating profiles for fully coupled finite-rate chemistry simulations, one-way coupled RAMP (Reacting And Multiphase Program using Method of Characteristics)-BLIMPJ (Boundary Layer Integral Matrix Program - Jet Version) derived solutions and variable and constant specific heat ratio frozen flow simulations. Variations in turbulence models, temperature boundary conditions and thermodynamic properties of the plume have been investigated at two ambient pressure conditions: 255 lb/sq ft (simulated low altitude) and 35 lb/sq ft (simulated high altitude). It is observed that the convective base heat flux and base temperature are most sensitive to the nozzle inner wall thermal boundary layer profile which is dependent on the wall temperature, boundary layer s specific energy and chemical reactions. Recovery shock dynamics and afterburning significantly influences convective base heating. Turbulence models and external nozzle wall thermal boundary layer profiles show less sensitivity to base heating characteristics. Base heating rates are validated for the highest fidelity solutions which show an agreement within +/-10% with respect to test data.

Lack of behavioural responses of humpback whales (Megaptera novaeangliae) indicate limited effectiveness of sonar mitigation

PubMed Central

Kvadsheim, Petter H.; Lam, Frans-Peter A.; von Benda-Beckmann, Alexander M.; Sivle, Lise D.; Visser, Fleur; Curé, Charlotte; Tyack, Peter L.; Miller, Patrick J. O.

2017-01-01

ABSTRACT Exposure to underwater sound can cause permanent hearing loss and other physiological effects in marine animals. To reduce this risk, naval sonars are sometimes gradually increased in intensity at the start of transmission (‘ramp-up’). Here, we conducted experiments in which tagged humpback whales were approached with a ship to test whether a sonar operation preceded by ramp-up reduced three risk indicators – maximum sound pressure level (SPLmax), cumulative sound exposure level (SELcum) and minimum source–whale range (Rmin) – compared with a sonar operation not preceded by ramp-up. Whales were subject to one no-sonar control session and either two successive ramp-up sessions (RampUp1, RampUp2) or a ramp-up session (RampUp1) and a full-power session (FullPower). Full-power sessions were conducted only twice; for other whales we used acoustic modelling that assumed transmission of the full-power sequence during their no-sonar control. Averaged over all whales, risk indicators in RampUp1 (n=11) differed significantly from those in FullPower (n=12) by −3.0 dB (SPLmax), −2.0 dB (SELcum) and +168 m (Rmin), but not significantly from those in RampUp2 (n=9). Only five whales in RampUp1, four whales in RampUp2 and none in FullPower or control sessions avoided the sound source. For RampUp1, we found statistically significant differences in risk indicators between whales that avoided the sonar and whales that did not: −4.7 dB (SPLmax), −3.4 dB (SELcum) and +291 m (Rmin). In contrast, for RampUp2, these differences were smaller and not significant. This study suggests that sonar ramp-up has a positive but limited mitigative effect for humpback whales overall, but that ramp-up can reduce the risk of harm more effectively in situations when animals are more responsive and likely to avoid the sonar, e.g. owing to novelty of the stimulus, when they are in the path of an approaching sonar ship. PMID:29141878

Role of Receptor Activity Modifying Protein 1 in Function of the Calcium Sensing Receptor in the Human TT Thyroid Carcinoma Cell Line

PubMed Central

Desai, Aditya J.; Roberts, David J.

2014-01-01

The Calcium Sensing Receptor (CaSR) plays a role in calcium homeostasis by sensing minute changes in serum Ca2+ and modulating secretion of calciotropic hormones. It has been shown in transfected cells that accessory proteins known as Receptor Activity Modifying Proteins (RAMPs), specifically RAMPs 1 and 3, are required for cell-surface trafficking of the CaSR. These effects have only been demonstrated in transfected cells, so their physiological relevance is unclear. Here we explored CaSR/RAMP interactions in detail, and showed that in thyroid human carcinoma cells, RAMP1 is required for trafficking of the CaSR. Furthermore, we show that normal RAMP1 function is required for intracellular responses to ligands. Specifically, to confirm earlier studies with tagged constructs, and to provide the additional benefit of quantitative stoichiometric analysis, we used fluorescence resonance energy transfer to show equal abilities of RAMP1 and 3 to chaperone CaSR to the cell surface, though RAMP3 interacted more efficiently with the receptor. Furthermore, a higher fraction of RAMP3 than RAMP1 was observed in CaSR-complexes on the cell-surface, suggesting different ratios of RAMPs to CaSR. In order to determine relevance of these findings in an endogenous expression system we assessed the effect of RAMP1 siRNA knock-down in medullary thyroid carcinoma TT cells, (which express RAMP1, but not RAMP3 constitutively) and measured a significant 50% attenuation of signalling in response to CaSR ligands Cinacalcet and neomycin. Blockade of RAMP1 using specific antibodies induced a concentration-dependent reduction in CaSR-mediated signalling in response to Cinacalcet in TT cells, suggesting a novel functional role for RAMP1 in regulation of CaSR signalling in addition to its known role in receptor trafficking. These data provide evidence that RAMPs traffic the CaSR as higher-level oligomers and play a role in CaSR signalling even after cell surface localisation has occurred. PMID:24454825

Role of receptor activity modifying protein 1 in function of the calcium sensing receptor in the human TT thyroid carcinoma cell line.

PubMed

Desai, Aditya J; Roberts, David J; Richards, Gareth O; Skerry, Timothy M

2014-01-01

The Calcium Sensing Receptor (CaSR) plays a role in calcium homeostasis by sensing minute changes in serum Ca(2+) and modulating secretion of calciotropic hormones. It has been shown in transfected cells that accessory proteins known as Receptor Activity Modifying Proteins (RAMPs), specifically RAMPs 1 and 3, are required for cell-surface trafficking of the CaSR. These effects have only been demonstrated in transfected cells, so their physiological relevance is unclear. Here we explored CaSR/RAMP interactions in detail, and showed that in thyroid human carcinoma cells, RAMP1 is required for trafficking of the CaSR. Furthermore, we show that normal RAMP1 function is required for intracellular responses to ligands. Specifically, to confirm earlier studies with tagged constructs, and to provide the additional benefit of quantitative stoichiometric analysis, we used fluorescence resonance energy transfer to show equal abilities of RAMP1 and 3 to chaperone CaSR to the cell surface, though RAMP3 interacted more efficiently with the receptor. Furthermore, a higher fraction of RAMP3 than RAMP1 was observed in CaSR-complexes on the cell-surface, suggesting different ratios of RAMPs to CaSR. In order to determine relevance of these findings in an endogenous expression system we assessed the effect of RAMP1 siRNA knock-down in medullary thyroid carcinoma TT cells, (which express RAMP1, but not RAMP3 constitutively) and measured a significant 50% attenuation of signalling in response to CaSR ligands Cinacalcet and neomycin. Blockade of RAMP1 using specific antibodies induced a concentration-dependent reduction in CaSR-mediated signalling in response to Cinacalcet in TT cells, suggesting a novel functional role for RAMP1 in regulation of CaSR signalling in addition to its known role in receptor trafficking. These data provide evidence that RAMPs traffic the CaSR as higher-level oligomers and play a role in CaSR signalling even after cell surface localisation has occurred.

Ramp-related incidents involving wheeled mobility device users during transit bus boarding/alighting.

PubMed

Frost, Karen L; Bertocci, Gina; Smalley, Craig

2015-05-01

To estimate the prevalence of wheeled mobility device (WhMD) ramp-related incidents while boarding/alighting a public transit bus and to determine whether the frequency of incidents is less when the ramp slope meets the proposed Americans with Disabilities Act (ADA) maximum allowable limit of ≤9.5°. Observational study. Community public transportation. WhMD users (N=414) accessing a public transit bus equipped with an instrumented ramp. Not applicable. Prevalence of boarding/alighting incidents involving WhMD users and associated ramp slopes; factors affecting incidents. A total of 4.6% (n=35) of WhMD users experienced an incident while boarding/alighting a transit bus. Significantly more incidents occurred during boarding (6.3%, n=26) than during alighting (2.2%, n=9) (P<.01), and when the ramp was deployed to street level (mean slope=11.4°) compared with sidewalk level (mean slope=4.2°) (P=.01). The odds ratio for experiencing an incident when the ramp slope exceeded the proposed ADA maximum allowable ramp slope was 5.4 (95% confidence interval, 2.4-12.2; P<.01). The odds ratio for assistance being rendered to board/alight when the ramp slope exceeded the proposed ADA maximum allowable ramp slope was 5.1 (95% confidence interval, 2.9-9.0; P<.01). The findings of this study support the proposed ADA maximum allowable ramp slope of 9.5°. Ramp slopes >9.5° and ramps deployed to street level are associated with a higher frequency of incidents and provision of assistance. Transit agencies should increase awareness among bus operators of the effect kneeling and deployment location (street/sidewalk) have on the ramp slope. In addition, ramp components and the built environment may contribute to incidents. When prescribing WhMDs, skills training must include ascending/descending ramps at slopes encountered during boarding/alighting to ensure safe and independent access to public transit buses. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Reevaluation of Ramp Design Speed Criteria

DOT National Transportation Integrated Search

1999-12-01

Current freeway entry ramp design speed criteria were evaluated through observations of twenty ramps in four Texas cities. Field observations of ramp and freeway traffic speed-distance relationships were made using videotaping methods. Traffic operat...

Sensitivity to changes in amplitude envelope

NASA Astrophysics Data System (ADS)

Gallun, Erick; Hafter, Ervin R.; Bonnel, Anne-Marie

2002-05-01

Detection of a brief increment in a tonal pedestal is less well predicted by energy-detection (e.g., Macmillan, 1973; Bonnel and Hafter, 1997) than by sensitivity to changes in the stimulus envelope. As this implies a mechanism similar to an envelope extractor (Viemeister, 1979), sinusoidal amplitude modulation was used to mask a single ramped increment (10, 45, or 70 ms) added to a 1000-ms pedestal with carrier frequency (cf)=477 Hz. As in informational masking (Neff, 1994) and ``modulation-detection interference'' (Yost and Sheft, 1989), interference occurred with masker cfs of 477 and 2013 Hz. While slight masking was found with modulation frequencies (mfs) from 16 to 96 Hz, masking grew inversely with still lower mfs, being greatest for mf=4 Hz. This division is reminiscent of that said to separate sensations of ``roughness'' and ``beats,'' respectively (Terhardt, 1974), with the latter also being related to durations associated with auditory groupings in music and speech. Importantly, this result held for all of the signal durations and onset-offset ramps tested, suggesting that an increment on a pedestal is treated as a single auditory object whose detection is most difficult in the presence of other objects (in this case, ``beats'').

Fast machine-learning online optimization of ultra-cold-atom experiments.

PubMed

Wigley, P B; Everitt, P J; van den Hengel, A; Bastian, J W; Sooriyabandara, M A; McDonald, G D; Hardman, K S; Quinlivan, C D; Manju, P; Kuhn, C C N; Petersen, I R; Luiten, A N; Hope, J J; Robins, N P; Hush, M R

2016-05-16

We apply an online optimization process based on machine learning to the production of Bose-Einstein condensates (BEC). BEC is typically created with an exponential evaporation ramp that is optimal for ergodic dynamics with two-body s-wave interactions and no other loss rates, but likely sub-optimal for real experiments. Through repeated machine-controlled scientific experimentation and observations our 'learner' discovers an optimal evaporation ramp for BEC production. In contrast to previous work, our learner uses a Gaussian process to develop a statistical model of the relationship between the parameters it controls and the quality of the BEC produced. We demonstrate that the Gaussian process machine learner is able to discover a ramp that produces high quality BECs in 10 times fewer iterations than a previously used online optimization technique. Furthermore, we show the internal model developed can be used to determine which parameters are essential in BEC creation and which are unimportant, providing insight into the optimization process of the system.

Fast machine-learning online optimization of ultra-cold-atom experiments

PubMed Central

Wigley, P. B.; Everitt, P. J.; van den Hengel, A.; Bastian, J. W.; Sooriyabandara, M. A.; McDonald, G. D.; Hardman, K. S.; Quinlivan, C. D.; Manju, P.; Kuhn, C. C. N.; Petersen, I. R.; Luiten, A. N.; Hope, J. J.; Robins, N. P.; Hush, M. R.

2016-01-01

We apply an online optimization process based on machine learning to the production of Bose-Einstein condensates (BEC). BEC is typically created with an exponential evaporation ramp that is optimal for ergodic dynamics with two-body s-wave interactions and no other loss rates, but likely sub-optimal for real experiments. Through repeated machine-controlled scientific experimentation and observations our ‘learner’ discovers an optimal evaporation ramp for BEC production. In contrast to previous work, our learner uses a Gaussian process to develop a statistical model of the relationship between the parameters it controls and the quality of the BEC produced. We demonstrate that the Gaussian process machine learner is able to discover a ramp that produces high quality BECs in 10 times fewer iterations than a previously used online optimization technique. Furthermore, we show the internal model developed can be used to determine which parameters are essential in BEC creation and which are unimportant, providing insight into the optimization process of the system. PMID:27180805

Vortex generation and mixing in three-dimensional supersonic combustors

NASA Technical Reports Server (NTRS)

Riggins, D. W.; Vitt, P. H.

1993-01-01

The generation and evolution of the flow vorticity established by instream injector ramps in a high Mach number/high enthalpy scramjet combustor flow-field are described in detail for a number of computational cases. Classical fluid dynamic circulation is presented for these cases in order to clarify the spatial distribution and convection of the vorticity. The ability of the simulations to accurately represent Stokes Law of circulation is discussed and shown. In addition, the conservation of swirl (effectively the moment-of-momentum theorem) is presented for these flows. The impact of both turbulent diffusion and the vortex/ramp non-uniformity on the downstream mixing rate is clearly illustrated. A correlation over the length of the combustor between fuel-air mixing and a parameter called the vortex stirring length is demonstrated. Finally, computational results for a representative ramp injector are compared with experimental data. Influence of the stream vorticity on the effective turbulent Prandtl number used in the simulation is discussed.

Ramp sedimentation in the Dinantian limestones of the Shannon Trough, Co. Limerick, Ireland

NASA Astrophysics Data System (ADS)

Somerville, Ian D.; Strogen, Peter

1992-08-01

During the late Chadian and Arundian (Lower Carboniferous), an extensive carbonate ramp (Limerick Ramp) developed over County Limerick, southwest Ireland, dipping northwestwards. Three distinct facies can be recognised corresponding to position on this ramp: inner, mid- and outer ramp. The inner ramp facies of oolitic and crinoidal grainstones (Herbertstown Limestone Formation) in east Limerick formed a major shoal behind which peritidal limestones were deposited. The mid-ramp facies of muddy bioclastic limestones and shales (Cooperhill facies) in north Limerick formed between fairweather and storm wave bases. The outer ramp (basinal) facies of mudstones and thin graded resedimented limestones (Rathkeale Beds) in west Limerick developed below storm wave base when fine terrigenous input was high. Later in the Arundian there was progradation of the nearshore oolitic and crinoidal grainstones over the mid-ramp facies. By the Holkerian, the deep-water basinal facies in west Limerick was buried beneath mid-ramp facies (Durnish Limestone). The initiation of the Limerick Ramp is closely related to the formation of the Shannon Trough. In the late Courceyan, accelerated subsidence in the Shannon area during deposition of Waulsortian facies marked the onset of a sag phase. Following a quiescent period in early Chadian, subsidence was renewed in the late Chadian and Arundian, when major facies changes occurred on the ramp. Comparison of the Shannon Trough with the Dublin Basin shows that in the latter, tectonic events in the Chadian and Arundian, particularly syn-sedimentary faulting, created a sharp division between platform and basinal sedimentation. Such tectonic influence is not recognised in the Shannon Trough. Here differential subsidence and eustatic sea-level changes led to more permanent ramp existence, modified only by westwards progradation.

Is the activity of CGRP and Adrenomedullin regulated by RAMP (-2) and (-3) in Trypanosomatidae? An in-silico approach.

PubMed

Febres, Anthony; Vanegas, Oriana; Giammarresi, Michelle; Gomes, Carlos; Díaz, Emilia; Ponte-Sucre, Alicia

2018-07-01

The Calcitonin-Like Receptor (CLR) belongs to the classical seven-transmembrane segment molecules coupled to heterotrimeric G proteins. Its pharmacology depends on the simultaneous expression of the so-called Receptor Activity Modifier Proteins (RAMP-) -1, -2 and -3. RAMP-associated proteins modulate glycosylation and cellular traffic of CLR, therefore determining its pharmacodynamics. In higher eukaryotes, the complex formed by CLR and RAMP-1 is more akin to bind Calcitonin Gene-Related Peptide (CGRP), whereas those formed by CLR and RAMP-2 or RAMP-3, bind preferentially Adrenomedullin (AM). In lower eukaryotes, RAMPs, or any homologous protein, have not been identified until now. Herein we demonstrated a negative chemotactic response elicited by CGRP (10 -9 and 10 -8  M) and AM (10 -9 to 10 -5  M). Whether or not this response is receptor mediated should be verified, as well as the expression of a 24 kDa band in Leishmania, recognized by western blot analysis by the use of (human-)-RAMP-2 antibodies as detection probes. Queries with human RAMP-2 and RAMP-3 protein sequences in blastp against Leishmania (Viannia) braziliensis predicted proteome, allowed us to detect two sequence alignments in the parasite: A RAMP-2-aligned sequence corresponding to Leishmania folylpolyglutamate synthase (FPGS), and a RAMP-3 aligned protein, a hypothetical Leishmania protein with yet unknown function. The presence of homologous of these proteins was described in-silico in other members of the Trypanosomatidae. These preliminary and not yet complete data suggest the feasibility that both CGRP and Adrenomedullin activities may be regulated by homologs of RAMP- (-2) and (-3) in these parasites. Copyright © 2018 Elsevier B.V. All rights reserved.

San Antonio relay ramp: Area of stratal continuity between large-displacement barrier faults of the Edwards aquifer and Balcones fault zone, central Texas

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

Collins, E.W.

1996-09-01

The San Antonio relay ramp, a gentle southwest-dipping monocline, formed between the tips of two en echelon master faults having maximum throws of >240 in. Structural analysis of this relay ramp is important to studies of Edwards aquifer recharge and ground-water flow because the ramp is an area of relatively good stratal continuity linking the outcrop belt recharge zone and unconfined aquifer with the downdip confined aquifer. Part of the relay ramp lies within the aquifer recharge zone and is crossed by several southeast-draining creeks, including Salado, Cibolo, and Comal Creeks, that supply water to the ramp recharge area. Thismore » feature is an analog for similar structures within the aquifer and for potential targets for hydrocarbons in other Gulf Coast areas. Defining the ramp is an {approximately}13-km-wide right step of the Edwards Group outcrop belt and the en echelon master faults that bound the ramp. The master faults strike N55-75{degrees}E, and maximum displacement exceeds the {approximately}165-m thickness of the Edwards Group strata. The faults therefore probably serve as barriers to Edwards ground-water flow. Within the ramp, tilted strata gently dip southwestward at {approximately}5 m/km, and the total structural relief along the ramp`s southwest-trending axis is <240 in. The ramp`s internal framework is defined by three fault blocks that are {approximately}4 to {approximately}6 km wide and are bound by northeast-striking faults having maximum throws between 30 and 150 m. Within the fault blocks, local areas of high fracture permeability may exist where smaller faults and joints are well connected.« less

Calcitonin and Amylin Receptor Peptide Interaction Mechanisms

PubMed Central

Lee, Sang-Min; Hay, Debbie L.; Pioszak, Augen A.

2016-01-01

Receptor activity-modifying proteins (RAMP1–3) determine the selectivity of the class B G protein-coupled calcitonin receptor (CTR) and the CTR-like receptor (CLR) for calcitonin (CT), amylin (Amy), calcitonin gene-related peptide (CGRP), and adrenomedullin (AM) peptides. RAMP1/2 alter CLR selectivity for CGRP/AM in part by RAMP1 Trp-84 or RAMP2 Glu-101 contacting the distinct CGRP/AM C-terminal residues. It is unclear whether RAMPs use a similar mechanism to modulate CTR affinity for CT and Amy, analogs of which are therapeutics for bone disorders and diabetes, respectively. Here, we reproduced the peptide selectivity of intact CTR, AMY1 (CTR·RAMP1), and AMY2 (CTR·RAMP2) receptors using purified CTR extracellular domain (ECD) and tethered RAMP1- and RAMP2-CTR ECD fusion proteins and antagonist peptides. All three proteins bound salmon calcitonin (sCT). Tethering RAMPs to CTR enhanced binding of rAmy, CGRP, and the AMY antagonist AC413. Peptide alanine-scanning mutagenesis and modeling of receptor-bound sCT and AC413 supported a shared non-helical CGRP-like conformation for their TN(T/V)G motif prior to the C terminus. After this motif, the peptides diverged; the sCT C-terminal Pro was crucial for receptor binding, whereas the AC413/rAmy C-terminal Tyr had little or no influence on binding. Accordingly, mutant RAMP1 W84A- and RAMP2 E101A-CTR ECD retained AC413/rAmy binding. ECD binding and cell-based signaling assays with antagonist sCT/AC413/rAmy variants with C-terminal residue swaps indicated that the C-terminal sCT/rAmy residue identity affects affinity more than selectivity. rAmy(8–37) Y37P exhibited enhanced antagonism of AMY1 while retaining selectivity. These results reveal unexpected differences in how RAMPs determine CTR and CLR peptide selectivity and support the hypothesis that RAMPs allosterically modulate CTR peptide affinity. PMID:26895962

Hall effects on unsteady MHD flow of second grade fluid through porous medium with ramped wall temperature and ramped surface concentration

NASA Astrophysics Data System (ADS)

VeeraKrishna, M.; Chamkha, Ali J.

2018-05-01

The heat generation/absorption and thermo-diffusion on an unsteady free convective MHD flow of radiating and chemically reactive second grade fluid near an infinite vertical plate through a porous medium and taking the Hall current into account have been studied. Assume that the bounding plate has a ramped temperature with a ramped surface concentration and isothermal temperature with a ramped surface concentration. The analytical solutions for the governing equations are obtained by making use of the Laplace transforms technique. The velocity, temperature, and concentration profiles are discussed through graphs. We also found that velocity, temperature, and concentration profiles in the case of ramped temperature with ramped surface concentrations are less than those of isothermal temperature with ramped surface concentrations. Also, the expressions of the skin friction, Nusselt number, and Sherwood number are obtained and represented computationally through a tabular form.

Crash location correction for freeway interchange modeling : research summary.

DOT National Transportation Integrated Search

2016-06-01

The project found that 69% of : all reviewed crashes were : landed incorrectly within the : interchange. The error rates by : facility type were 90% for : ramps, 79% for terminals, and : 53% for speed-change lanes.

Coastal eolian sand-ramp development related to paleo-sea-level changes during the Latest Pleistocene and Holocene (21–0 ka) in San Miguel Island, California, U.S.A.

USGS Publications Warehouse

Peterson, Curt D.; Erlandson, Jon M.; Stock, Errol; Hostetler, Steven W.; Price, David M.

2017-01-01

Coastal eolian sand ramps (5–130 m elevation) on the northern slope (windward) side of the small San Miguel Island (13 km in W-E length) range in age from late Pleistocene to modern time, though a major hiatus in sand-ramp growth occurred during the early Holocene marine transgression (16–9 ka). The Holocene sand ramps (1–5 m measured thicknesses) currently lack large dune forms, thereby representing deflated erosional remnants, locally covering thicker late Pleistocene sand-ramp deposits. The ramp sand was initially supplied from the adjacent island-shelf platform, extending about 20 km north of the present coastline. The sand-ramp deposits and interbedded loess soils were 14C dated using 112 samples from 32 archaeological sites and other geologic sections. Latest Pleistocene sand ramps (66–18 ka) were derived from across-shelf eolian sand transport during marine low stands. Shoreward wave transport supplied remobilized late Pleistocene sand from the inner shelf to Holocene beaches, where dominant NW winds supplied sand to the sand ramps. The onset dates of the sand-ramp deposition in San Miguel are 7.2 ± 1.5 ka (sample n = 14). The internal strata dates in the vertically accreting sand ramps are 3.4 ± 1.7 ka (n = 34). The sand ramps in San Miguel show wide-scale termination of sand supply in the latest Holocene time. The sand-ramp top dates or burial dates are 1.7 ± 0.9 ka (n = 28). The latest Holocene sand ramps are truncated along most of the island's northern coastline, indicating recent losses of nearshore sand reserves to onshore, alongshore, and, possibly, offshore sand sinks. The truncated sand ramps in San Miguel Island and in other sand-depleted marine coastlines provide warnings about future beach erosion and/or shoreline retreat from accelerated sea-level rise accompanying predicted global warming.

Evaluation of temporary ramp metering for work zones.

DOT National Transportation Integrated Search

2012-11-01

Ramp metering has been successfully implemented in many states to improve traffic operations on freeways. Studies have documented the positive mobility and safety benefits of ramp metering. However, there have been no studies on the use of ramp meter...

Supersonic Elliptical Ramp Inlet

NASA Technical Reports Server (NTRS)

Adamson, Eric E. (Inventor); Fink, Lawrence E. (Inventor); Fugal, Spencer R. (Inventor)

2016-01-01

A supersonic inlet includes a supersonic section including a cowl which is at least partially elliptical, a ramp disposed within the cowl, and a flow inlet disposed between the cowl and the ramp. The ramp may also be at least partially elliptical.

Lack of behavioural responses of humpback whales (Megaptera novaeangliae) indicate limited effectiveness of sonar mitigation.

PubMed

Wensveen, Paul J; Kvadsheim, Petter H; Lam, Frans-Peter A; von Benda-Beckmann, Alexander M; Sivle, Lise D; Visser, Fleur; Curé, Charlotte; Tyack, Peter L; Miller, Patrick J O

2017-11-15

Exposure to underwater sound can cause permanent hearing loss and other physiological effects in marine animals. To reduce this risk, naval sonars are sometimes gradually increased in intensity at the start of transmission ('ramp-up'). Here, we conducted experiments in which tagged humpback whales were approached with a ship to test whether a sonar operation preceded by ramp-up reduced three risk indicators - maximum sound pressure level (SPL max ), cumulative sound exposure level (SEL cum ) and minimum source-whale range ( R min ) - compared with a sonar operation not preceded by ramp-up. Whales were subject to one no-sonar control session and either two successive ramp-up sessions (RampUp1, RampUp2) or a ramp-up session (RampUp1) and a full-power session (FullPower). Full-power sessions were conducted only twice; for other whales we used acoustic modelling that assumed transmission of the full-power sequence during their no-sonar control. Averaged over all whales, risk indicators in RampUp1 ( n =11) differed significantly from those in FullPower ( n =12) by -3.0 dB (SPL max ), -2.0 dB (SEL cum ) and +168 m ( R min ), but not significantly from those in RampUp2 ( n =9). Only five whales in RampUp1, four whales in RampUp2 and none in FullPower or control sessions avoided the sound source. For RampUp1, we found statistically significant differences in risk indicators between whales that avoided the sonar and whales that did not: -4.7 dB (SPL max ), -3.4 dB (SEL cum ) and +291 m ( R min ). In contrast, for RampUp2, these differences were smaller and not significant. This study suggests that sonar ramp-up has a positive but limited mitigative effect for humpback whales overall, but that ramp-up can reduce the risk of harm more effectively in situations when animals are more responsive and likely to avoid the sonar, e.g. owing to novelty of the stimulus, when they are in the path of an approaching sonar ship. © 2017. Published by The Company of Biologists Ltd.

Neuromorphic meets neuromechanics, part II: the role of fusimotor drive.

PubMed

Jalaleddini, Kian; Minos Niu, Chuanxin; Chakravarthi Raja, Suraj; Joon Sohn, Won; Loeb, Gerald E; Sanger, Terence D; Valero-Cuevas, Francisco J

2017-04-01

We studied the fundamentals of muscle afferentation by building a Neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties). The motor commands were transformed into tendon forces by a Hill-type muscle model (with activation-contraction dynamics) via brushless DC motors. Two independent afferented muscles emulated the forces of flexor digitorum profundus and the extensor indicis proprius muscles, forming an antagonist pair at the metacarpophalangeal joint of a cadaveric index finger. We measured the physical response to repetitions of bi-directional ramp-and-hold rotational perturbations for 81 combinations of static and dynamic fusimotor drives, across four ramp velocities, and three levels of constant cortical drive to the α-motor neuron pool. We found that this system produced responses compatible with the physiological literature. Fusimotor and cortical drives had nonlinear effects on the reflex forces. In particular, only cortical drive affected the sensitivity of reflex forces to static fusimotor drive. In contrast, both static fusimotor and cortical drives reduced the sensitivity to dynamic fusimotor drive. Interestingly, realistic signal-dependent motor noise emerged naturally in our system without having been explicitly modeled. We demonstrate that these fundamental features of spinal afferentation sufficed to produce muscle function. As such, our Neuro-mechano-morphic system is a viable platform to study the spinal mechanisms for healthy muscle function-and its pathologies such as dystonia and spasticity. In addition, it is a working prototype of a robust biomorphic controller for compliant robotic limbs and exoskeletons.

Neuromorphic meets neuromechanics, part II: the role of fusimotor drive

NASA Astrophysics Data System (ADS)

Jalaleddini, Kian; Minos Niu, Chuanxin; Chakravarthi Raja, Suraj; Sohn, Won Joon; Loeb, Gerald E.; Sanger, Terence D.; Valero-Cuevas, Francisco J.

2017-04-01

Objective. We studied the fundamentals of muscle afferentation by building a Neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. Approach. As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties). The motor commands were transformed into tendon forces by a Hill-type muscle model (with activation-contraction dynamics) via brushless DC motors. Two independent afferented muscles emulated the forces of flexor digitorum profundus and the extensor indicis proprius muscles, forming an antagonist pair at the metacarpophalangeal joint of a cadaveric index finger. We measured the physical response to repetitions of bi-directional ramp-and-hold rotational perturbations for 81 combinations of static and dynamic fusimotor drives, across four ramp velocities, and three levels of constant cortical drive to the α-motor neuron pool. Main results. We found that this system produced responses compatible with the physiological literature. Fusimotor and cortical drives had nonlinear effects on the reflex forces. In particular, only cortical drive affected the sensitivity of reflex forces to static fusimotor drive. In contrast, both static fusimotor and cortical drives reduced the sensitivity to dynamic fusimotor drive. Interestingly, realistic signal-dependent motor noise emerged naturally in our system without having been explicitly modeled. Significance. We demonstrate that these fundamental features of spinal afferentation sufficed to produce muscle function. As such, our Neuro-mechano-morphic system is a viable platform to study the spinal mechanisms for healthy muscle function—and its pathologies such as dystonia and spasticity. In addition, it is a working prototype of a robust biomorphic controller for compliant robotic limbs and exoskeletons.

Neuromorphic Meets Neuromechanics, Part II: The Role of Fusimotor Drive

PubMed Central

Jalaleddini, Kian; Minos Niu, Chuanxin; Chakravarthi Raja, Suraj; Joon Sohn, Won; Loeb, Gerald E.; Sanger, Terence D.; Valero-Cuevas, Francisco J.

2017-01-01

Objective We studied the fundamentals of muscle afferentation by building a neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. Approach As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties). The motor commands were transformed into tendon forces by a Hill-type muscle model (with activation-contraction dynamics) via brushless DC motors. Two independent afferented muscles emulated the forces of flexor digitorum profundus and the extensor indicis proprius muscles, forming an antagonist pair at the metacarpophalangeal joint of a cadaveric index finger. We measured the physical response to repetitions of bidirectional ramp-and-hold rotational perturbations for 81 combinations of static and dynamic fusimotor drives, across four ramp velocities, and three levels of constant cortical drive to the α-motor neuron pool. Results We found that this system produced responses compatible with the physiological literature. Fusimotor and cortical drives had nonlinear effects on the reflex forces. In particular, only cortical drive affected the sensitivity of reflex forces to static fusimotor drive. In contrast, both static fusimotor and cortical drives reduced the sensitivity to dynamic fusimotor drive. Interestingly, realistic signal-dependent motor noise emerged naturally in our system without having been explicitly modeled. Significance We demonstrate that these fundamental features of spinal afferentation sufficed to produce muscle function. As such, our neuro-mechano-morphic system is a viable platform to study the spinal mechanisms for healthy muscle function — and its pathologies such as dystonia and spasticity. In addition, it is a working prototype of a robust biomorphic controller for compliant robotic limbs and exoskeletons. PMID:28094764

Isotonic force modulates force redevelopment rate of intact frog muscle fibres: evidence for cross-bridge induced thin filament activation

PubMed Central

Vandenboom, Rene; Hannon, James D; Sieck, Gary C

2002-01-01

We tested the hypothesis that force-velocity history modulates thin filament activation, as assessed by the rate of force redevelopment after shortening (+dF/dtR). The influence of isotonic force on +dF/dtR was assessed by imposing uniform amplitude (2.55 to 2.15 μm sarcomere−1) but different speed releases to intact frog muscle fibres during fused tetani. Each release consisted of a contiguous ramp- and step-change in length. Ramp speed was changed from release to release to vary fibre shortening speed from 1.00 (2.76 ± 0.11 μm half-sarcomere−1 s−1) to 0.30 of maximum unloaded shortening velocity (Vu), thereby modulating isotonic force from 0 to 0.34 Fo, respectively. The step zeroed force and allowed the fibre to shorten unloaded for a brief period of time prior to force redevelopment. Although peak force redevelopment after different releases was similar, +dF/dtR increased by 81 ± 6% (P < 0.05) as fibre shortening speed was reduced from 1.00 Vu. The +dF/dtR after different releases was strongly correlated with the preceding isotonic force (r = 0.99, P < 0.001). Results from additional experiments showed that the slope of slack test plots produced by systematically increasing the step size that followed each ramp were similar. Thus, isotonic force did not influence Vu (mean: 2.84 ± 0.10 μm half-sarcomere−1 s−1, P < 0.05). We conclude that isotonic force modulates +dF/dtR independent of change in Vu, an outcome consistent with a cooperative influence of attached cross-bridges on thin filament activation that increases cross-bridge attachment rate without alteration to cross-bridge detachment rate. PMID:12205189

The processing of aluminum gasarites via thermal decomposition of interstitial hydrides

NASA Astrophysics Data System (ADS)

Licavoli, Joseph J.

Gasarite structures are a unique type of metallic foam containing tubular pores. The original methods for their production limited them to laboratory study despite appealing foam properties. Thermal decomposition processing of gasarites holds the potential to increase the application of gasarite foams in engineering design by removing several barriers to their industrial scale production. The following study characterized thermal decomposition gasarite processing both experimentally and theoretically. It was found that significant variation was inherent to this process therefore several modifications were necessary to produce gasarites using this method. Conventional means to increase porosity and enhance pore morphology were studied. Pore morphology was determined to be more easily replicated if pores were stabilized by alumina additions and powders were dispersed evenly. In order to better characterize processing, high temperature and high ramp rate thermal decomposition data were gathered. It was found that the high ramp rate thermal decomposition behavior of several hydrides was more rapid than hydride kinetics at low ramp rates. This data was then used to estimate the contribution of several pore formation mechanisms to the development of pore structure. It was found that gas-metal eutectic growth can only be a viable pore formation mode if non-equilibrium conditions persist. Bubble capture cannot be a dominant pore growth mode due to high bubble terminal velocities. Direct gas evolution appears to be the most likely pore formation mode due to high gas evolution rate from the decomposing particulate and microstructural pore growth trends. The overall process was evaluated for its economic viability. It was found that thermal decomposition has potential for industrialization, but further refinements are necessary in order for the process to be viable.

Static internal performance of convergent single-expansion-ramp nozzles with various combinations of internal geometric parameters

NASA Technical Reports Server (NTRS)

Bare, E. Ann; Capone, Francis J.

1989-01-01

An investigation was conducted in the Static Test Facility of the Langley 16-Foot Transonic Tunnel to determine the effects of five geometric design parameters on the internal performance of convergent single expansion ramp nozzles. The effects of ramp chordal angle, initial ramp angle, flap angle, flap length, and ramp length were determined. All nozzles tested has a nominally constant throat area and aspect ratio. Static pressure distributions along the centerlines of the ramp and flap were also obtained for each configuration. Nozzle pressure ratio was varied up to 10.0 for all configurations.

A study of the rate-controlled constrained-equilibrium dimension reduction method and its different implementations

NASA Astrophysics Data System (ADS)

Hiremath, Varun; Pope, Stephen B.

2013-04-01

The Rate-Controlled Constrained-Equilibrium (RCCE) method is a thermodynamic based dimension reduction method which enables representation of chemistry involving n s species in terms of fewer n r constraints. Here we focus on the application of the RCCE method to Lagrangian particle probability density function based computations. In these computations, at every reaction fractional step, given the initial particle composition (represented using RCCE), we need to compute the reaction mapping, i.e. the particle composition at the end of the time step. In this work we study three different implementations of RCCE for computing this reaction mapping, and compare their relative accuracy and efficiency. These implementations include: (1) RCCE/TIFS (Trajectory In Full Space): this involves solving a system of n s rate-equations for all the species in the full composition space to obtain the reaction mapping. The other two implementations obtain the reaction mapping by solving a reduced system of n r rate-equations obtained by projecting the n s rate-equations for species evaluated in the full space onto the constrained subspace. These implementations include (2) RCCE: this is the classical implementation of RCCE which uses a direct projection of the rate-equations for species onto the constrained subspace; and (3) RCCE/RAMP (Reaction-mixing Attracting Manifold Projector): this is a new implementation introduced here which uses an alternative projector obtained using the RAMP approach. We test these three implementations of RCCE for methane/air premixed combustion in the partially-stirred reactor with chemistry represented using the n s=31 species GRI-Mech 1.2 mechanism with n r=13 to 19 constraints. We show that: (a) the classical RCCE implementation involves an inaccurate projector which yields large errors (over 50%) in the reaction mapping; (b) both RCCE/RAMP and RCCE/TIFS approaches yield significantly lower errors (less than 2%); and (c) overall the RCCE/TIFS approach is the most accurate, efficient (by orders of magnitude) and robust implementation.

Force sensor in simulated skin and neural model mimic tactile SAI afferent spiking response to ramp and hold stimuli

PubMed Central

2012-01-01

Background The next generation of prosthetic limbs will restore sensory feedback to the nervous system by mimicking how skin mechanoreceptors, innervated by afferents, produce trains of action potentials in response to compressive stimuli. Prior work has addressed building sensors within skin substitutes for robotics, modeling skin mechanics and neural dynamics of mechanotransduction, and predicting response timing of action potentials for vibration. The effort here is unique because it accounts for skin elasticity by measuring force within simulated skin, utilizes few free model parameters for parsimony, and separates parameter fitting and model validation. Additionally, the ramp-and-hold, sustained stimuli used in this work capture the essential features of the everyday task of contacting and holding an object. Methods This systems integration effort computationally replicates the neural firing behavior for a slowly adapting type I (SAI) afferent in its temporally varying response to both intensity and rate of indentation force by combining a physical force sensor, housed in a skin-like substrate, with a mathematical model of neuronal spiking, the leaky integrate-and-fire. Comparison experiments were then conducted using ramp-and-hold stimuli on both the spiking-sensor model and mouse SAI afferents. The model parameters were iteratively fit against recorded SAI interspike intervals (ISI) before validating the model to assess its performance. Results Model-predicted spike firing compares favorably with that observed for single SAI afferents. As indentation magnitude increases (1.2, 1.3, to 1.4 mm), mean ISI decreases from 98.81 ± 24.73, 54.52 ± 6.94, to 41.11 ± 6.11 ms. Moreover, as rate of ramp-up increases, ISI during ramp-up decreases from 21.85 ± 5.33, 19.98 ± 3.10, to 15.42 ± 2.41 ms. Considering first spikes, the predicted latencies exhibited a decreasing trend as stimulus rate increased, as is observed in afferent recordings. Finally, the SAI afferent’s characteristic response of producing irregular ISIs is shown to be controllable via manipulating the output filtering from the sensor or adding stochastic noise. Conclusions This integrated engineering approach extends prior works focused upon neural dynamics and vibration. Future efforts will perfect measures of performance, such as first spike latency and irregular ISIs, and link the generation of characteristic features within trains of action potentials with current pulse waveforms that stimulate single action potentials at the peripheral afferent. PMID:22824523

Game-theoretic equilibrium analysis applications to deregulated electricity markets

NASA Astrophysics Data System (ADS)

Joung, Manho

This dissertation examines game-theoretic equilibrium analysis applications to deregulated electricity markets. In particular, three specific applications are discussed: analyzing the competitive effects of ownership of financial transmission rights, developing a dynamic game model considering the ramp rate constraints of generators, and analyzing strategic behavior in electricity capacity markets. In the financial transmission right application, an investigation is made of how generators' ownership of financial transmission rights may influence the effects of the transmission lines on competition. In the second application, the ramp rate constraints of generators are explicitly modeled using a dynamic game framework, and the equilibrium is characterized as the Markov perfect equilibrium. Finally, the strategic behavior of market participants in electricity capacity markets is analyzed and it is shown that the market participants may exaggerate their available capacity in a Nash equilibrium. It is also shown that the more conservative the independent system operator's capacity procurement, the higher the risk of exaggerated capacity offers.

Dynamics of vapor emissions at wire explosion thresholda)

NASA Astrophysics Data System (ADS)

Belony, Paul A.; Kim, Yong W.

2010-10-01

X-pinch plasmas have been actively studied in the recent years. Numerical simulation of the ramp-up of metallic vapor emissions from wire specimens shows that under impulsive Ohmic heating the wire core invariably reaches a supercritical state before explosion. The heating rate depends sensitively on the local wire resistance, leading to highly variable vapor emission flux along the wire. To examine the vapor emission process, we have visualized nickel wire explosions by means of shock formation in air. In a single explosion as captured by shadowgraphy, there usually appear several shocks with spherical or cylindrical wave front originating from different parts of the wire. Growth of various shock fronts in time is well characterized by a power-law scaling in one form or another. Continuum emission spectra are obtained and calibrated to measure temperature near the explosion threshold. Shock front structures and vapor plume temperature are examined.

Calcitonin and Amylin Receptor Peptide Interaction Mechanisms: INSIGHTS INTO PEPTIDE-BINDING MODES AND ALLOSTERIC MODULATION OF THE CALCITONIN RECEPTOR BY RECEPTOR ACTIVITY-MODIFYING PROTEINS.

PubMed

Lee, Sang-Min; Hay, Debbie L; Pioszak, Augen A

2016-04-15

Receptor activity-modifying proteins (RAMP1-3) determine the selectivity of the class B G protein-coupled calcitonin receptor (CTR) and the CTR-like receptor (CLR) for calcitonin (CT), amylin (Amy), calcitonin gene-related peptide (CGRP), and adrenomedullin (AM) peptides. RAMP1/2 alter CLR selectivity for CGRP/AM in part by RAMP1 Trp-84 or RAMP2 Glu-101 contacting the distinct CGRP/AM C-terminal residues. It is unclear whether RAMPs use a similar mechanism to modulate CTR affinity for CT and Amy, analogs of which are therapeutics for bone disorders and diabetes, respectively. Here, we reproduced the peptide selectivity of intact CTR, AMY1 (CTR·RAMP1), and AMY2 (CTR·RAMP2) receptors using purified CTR extracellular domain (ECD) and tethered RAMP1- and RAMP2-CTR ECD fusion proteins and antagonist peptides. All three proteins bound salmon calcitonin (sCT). Tethering RAMPs to CTR enhanced binding of rAmy, CGRP, and the AMY antagonist AC413. Peptide alanine-scanning mutagenesis and modeling of receptor-bound sCT and AC413 supported a shared non-helical CGRP-like conformation for their TN(T/V)G motif prior to the C terminus. After this motif, the peptides diverged; the sCT C-terminal Pro was crucial for receptor binding, whereas the AC413/rAmy C-terminal Tyr had little or no influence on binding. Accordingly, mutant RAMP1 W84A- and RAMP2 E101A-CTR ECD retained AC413/rAmy binding. ECD binding and cell-based signaling assays with antagonist sCT/AC413/rAmy variants with C-terminal residue swaps indicated that the C-terminal sCT/rAmy residue identity affects affinity more than selectivity. rAmy(8-37) Y37P exhibited enhanced antagonism of AMY1 while retaining selectivity. These results reveal unexpected differences in how RAMPs determine CTR and CLR peptide selectivity and support the hypothesis that RAMPs allosterically modulate CTR peptide affinity. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Test of electical resistivity and current diffusion modelling on MAST and JET

NASA Astrophysics Data System (ADS)

Keeling, D. L.; Challis, C. D.; Jenkins, I.; Hawkes, N. C.; Lupelli, I.; Michael, C.; de Bock, M. F. M.; the MAST Team; contributors, JET

2018-01-01

Experiments have been carried out on the MAST and JET tokamaks intended to compare the electrical resistivity of the plasma with theoretical formulations. The tests consist of obtaining motional stark effect (MSE) measurements in MHD-free plasmas during plasma current ramp-up (JET and MAST), ramp-down (MAST) and in stationary state (JET and MAST). Simulations of these plasmas are then performed in which the current profile evolution is calculated according to the poloidal field diffusion equation (PFDE) with classical or neoclassical resistivity. Synthetic MSE data are produced in the simulations for direct comparison with the experimental data. It is found that the toroidal current profile evolution modelled using neoclassical resistivity did not match the experimental observations on either device during current ramp-up or ramp-down as concluded from comparison of experimental and synthetic MSE profiles. In these phases, use of neoclassical resistivity in the modelling systematically overestimates the rate of current profile evolution. During the stationary state however, the modelled toroidal current profile matched experimental observations to a high degree of accuracy on both devices using neoclassical resistivity. Whilst no solution to the mismatch in the dynamic phases of the plasma is proposed, it is suggested that some physical process other than MHD which is not captured by the simple diffusive model of current profile evolution is responsible.

Novel Stimulation Paradigms with Temporally-Varying Parameters to Reduce Synchronous Activity at the Onset of High Frequency Stimulation in Rat Hippocampus

PubMed Central

Cai, Ziyan; Feng, Zhouyan; Guo, Zheshan; Zhou, Wenjie; Wang, Zhaoxiang; Wei, Xuefeng

2017-01-01

Deep brain stimulation (DBS) has shown wide applications for treating various disorders in the central nervous system by using high frequency stimulation (HFS) sequences of electrical pulses. However, upon the onset of HFS sequences, the narrow pulses could induce synchronous firing of action potentials among large populations of neurons and cause a transient phase of “onset response” that is different from the subsequent steady state. To investigate the transient onset phase, the antidromically-evoked population spikes (APS) were used as an electrophysiological marker to evaluate the synchronous neuronal reactions to axonal HFS in the hippocampal CA1 region of anesthetized rats. New stimulation paradigms with time-varying intensity and frequency were developed to suppress the “onset responses”. Results show that HFS paradigms with ramp-up intensity at the onset phase could suppress large APS potentials. In addition, an intensity ramp with a slower ramp-up rate or with a higher pulse frequency had greater suppression on APS amplitudes. Therefore, to reach a desired pulse intensity rapidly, a stimulation paradigm combining elevated frequency and ramp-up intensity was used to shorten the transition phase of initial HFS without evoking large APS potentials. The results of the study provide important clues for certain transient side effects of DBS and for development of new adaptive stimulation paradigms. PMID:29066946

Static internal performance of single-expansion-ramp nozzles with various combinations of internal geometric parameters

NASA Technical Reports Server (NTRS)

Re, R. J.; Leavitt, L. D.

1984-01-01

The effects of five geometric design parameters on the internal performance of single-expansion-ramp nozzles were investigated at nozzle pressure ratios up to 10 in the static-test facility of the Langley 16-Foot Transonic Tunnel. The geometric variables on the expansion-ramp surface of the upper flap consisted of ramp chordal angle, ramp length, and initial ramp angle. On the lower flap, the geometric variables consisted of flap angle and flap length. Both internal performance and static-pressure distributions on the centerlines of the upper and lower flaps were obtained for all 43 nozzle configurations tested.

Programmer's guide to the fuzzy logic ramp metering algorithm : software design, integration, testing, and evaluation

DOT National Transportation Integrated Search

2000-02-01

A Fuzzy Logic Ramp Metering Algorithm was implemented on 126 ramps in the greater Seattle area. This report documents the implementation of the Fuzzy Logic Ramp Metering Algorithm at the Northwest District of the Washington State Department of Transp...

Safety and operational performance evaluation of four types of exit ramps on Florida's freeways (final report).

DOT National Transportation Integrated Search

2010-12-01

This project mainly focuses on exit ramp performance analysis of safety and operations. In addition, issues of advance guide sign for exit ramp are also mentioned. : Safety analysis evaluates safety performances of different exit ramps used in Florid...

Separation attenuation in swept shock wave-boundary-layer interactions using different microvortex generator geometries

NASA Astrophysics Data System (ADS)

Martis, R. R.; Misra, A.

2017-09-01

A numerical study is conducted to determine the effectiveness of six different microvortex generator geometries in controlling swept shock wave/boundary-layer interactions. The geometries considered are base ramp, base ramp with declining angle of 45°, blunt ramp, split ramp, thick vanes, and ramped vanes. Microvortex generators with a gap were found to be better suited for delaying the separation. Thick vanes showed the largest delay in separation among the devices studied.

Magnetic ramp scale at supercritical perpendicular collisionless shocks: Full particle electromagnetic simulations

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

Yang, Zhongwei; SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, 200136; Lu, Quanming

2013-09-15

Supercritical perpendicular collisionless shocks are known to exhibit foot, ramp, and overshoot structures. The shock ramp structure is in a smaller scale in contrast to other microstructures (foot and overshoot) within the shock front. One-dimensional full particle simulations of strictly perpendicular shocks over wide ranges of ion beta β{sub i}, Alfvén Mach number M{sub A}, and ion-to-electron mass ratio m{sub i}/m{sub e} are presented to investigate the impact of plasma parameters on the shock ramp scale. Main results are (1) the ramp scale can be as small as several electron inertial length. (2) The simulations suggest that in a regimemore » below the critical ion beta value, the shock front undergoes a periodic self-reformation and the shock ramp scale is time-varying. At higher ion beta values, the shock front self-reformation is smeared. At still higher ion beta value, the motion of reflected ions is quite diffuse so that they can lead to a quasi-steady shock ramp. Throughout the above three conditions, the shock ramp thickness increases with β{sub i}. (3) The increase (decrease) in Mach number and the decrease (increase) in the beta value have almost equivalent impact on the state (i.e., stationary or nonstationary) of the shock ramp. Both of front and ramp thicknesses are increased with M{sub A}.« less

The modelling of an SF6 arc in a supersonic nozzle: II. Current zero behaviour of the nozzle arc

NASA Astrophysics Data System (ADS)

Zhang, Q.; Liu, J.; Yan, J. D.; Fang, M. T. C.

2016-08-01

The present work (part II) forms the second part of an investigation into the behaviour of SF6 nozzle arc. It is concerned with the aerodynamic and electrical behaviour of a transient nozzle arc under a current ramp specified by a rate of current decay (di/dt) before current zero and a voltage ramp (dV/dt) after current zero. The five flow models used in part I [1] for cold gas flow and DC nozzle arcs have been applied to study the transient arc at three stagnation pressures (P 0) and two values of di/dt for the current ramp, representing a wide range of arcing conditions. An analysis of the physical mechanisms encompassed in each flow model is given with an emphasis on the adequacy of a particular model in describing the rapidly varying arc around current zero. The critical rate of rise of recovery voltage (RRRV) is found computationally and compared with test results of Benenson et al [2]. For transient nozzle arcs, the RRRV is proportional to the square of P 0, rather than to the square root of P 0 for DC nozzle arcs. The physical mechanisms responsible for the strong dependence of RRRV on P 0 have been investigated. The relative merits of the flow models employed are discussed.

Detection of Gait Modes Using an Artificial Neural Network during Walking with a Powered Ankle-Foot Orthosis

PubMed Central

2016-01-01

This paper presents an algorithm, for use with a Portable Powered Ankle-Foot Orthosis (i.e., PPAFO) that can automatically detect changes in gait modes (level ground, ascent and descent of stairs or ramps), thus allowing for appropriate ankle actuation control during swing phase. An artificial neural network (ANN) algorithm used input signals from an inertial measurement unit and foot switches, that is, vertical velocity and segment angle of the foot. Output from the ANN was filtered and adjusted to generate a final data set used to classify different gait modes. Five healthy male subjects walked with the PPAFO on the right leg for two test scenarios (walking over level ground and up and down stairs or a ramp; three trials per scenario). Success rate was quantified by the number of correctly classified steps with respect to the total number of steps. The results indicated that the proposed algorithm's success rate was high (99.3%, 100%, and 98.3% for level, ascent, and descent modes in the stairs scenario, respectively; 98.9%, 97.8%, and 100% in the ramp scenario). The proposed algorithm continuously detected each step's gait mode with faster timing and higher accuracy compared to a previous algorithm that used a decision tree based on maximizing the reliability of the mode recognition. PMID:28070188

40 CFR 1033.520 - Alternative ramped modal cycles.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Following the completion of the third test phase of the applicable ramped modal cycle, conduct the post... POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test Procedures § 1033.520 Alternative ramped modal... locomotive notch settings. Ramped modal cycles combine multiple test modes of a discrete-mode steady-state...

3. Ramp No. 6 connection between Medical Detachment Barracks: Building ...

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

3. Ramp No. 6 connection between Medical Detachment Barracks: Building Nos. 9970-B (left) and 9969-B (right). The many windows makes this section almost unique among the ramps and corridors. - Madigan Hospital, Corridors & Ramps, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

Rapid qualification of CSP assemblies by increase of ramp rates and cycling temperature ranges

NASA Technical Reports Server (NTRS)

Ghaffarian, R.; Kim, N.; Rose, D.; Hunter, B.; Devitt, K.; Long, T.

2001-01-01

Team members representing government agencies and private companies have joined together to pool in-kind resources for developing the quality and reliability of chip scale packages (CSPs) for a variety of projects.

Demonstration of Essential Reliability Services by Utility-Scale Solar

Science.gov Websites

control (AGC) * Primary frequency control * Active power ramp rate control * Voltage regulation and reactive power control. See a list of Questions and Answers from the webinar. Read the NREL technical

F-15 HiDEC taxi on ramp at sunrise

NASA Image and Video Library

1991-09-23

NASA's highly modified F-15A (Serial #71-0287) used for digital electronic flight and engine control systems research, at sunrise on the ramp at the Dryden Flight Research Facility, Edwards, California. The F-15 was called the HIDEC (Highly Integrated Digital Electronic Control) flight facility. Research programs flown on the testbed vehicle have demonstrated improved rates of climb, fuel savings, and engine thrust by optimizing systems performance. The aircraft also tested and evaluated a computerized self-repairing flight control system for the Air Force that detects damaged or failed flight control surfaces. The system then reconfigures undamaged control surfaces so the mission can continue or the aircraft is landed safely.

Role of spike-frequency adaptation in shaping neuronal response to dynamic stimuli.

PubMed

Peron, Simon Peter; Gabbiani, Fabrizio

2009-06-01

Spike-frequency adaptation is the reduction of a neuron's firing rate to a stimulus of constant intensity. In the locust, the Lobula Giant Movement Detector (LGMD) is a visual interneuron that exhibits rapid adaptation to both current injection and visual stimuli. Here, a reduced compartmental model of the LGMD is employed to explore adaptation's role in selectivity for stimuli whose intensity changes with time. We show that supralinearly increasing current injection stimuli are best at driving a high spike count in the response, while linearly increasing current injection stimuli (i.e., ramps) are best at attaining large firing rate changes in an adapting neuron. This result is extended with in vivo experiments showing that the LGMD's response to translating stimuli having a supralinear velocity profile is larger than the response to constant or linearly increasing velocity translation. Furthermore, we show that the LGMD's preference for approaching versus receding stimuli can partly be accounted for by adaptation. Finally, we show that the LGMD's adaptation mechanism appears well tuned to minimize sensitivity for the level of basal input.

Vehicle operation characteristic under different ramp entrance conditions in underground road: Analysis, simulation and modelling

NASA Astrophysics Data System (ADS)

Yao, Qiming; Liu, Shuo; Liu, Yang

2018-05-01

An experimental design was used to study the vehicle operation characteristics of different ramp entrance conditions in underground road. With driving simulator, the experimental scenarios include left or right ramp with first, second and third service level, respectively, to collect vehicle speed, acceleration, lateral displacement and location information at the ramp entrance section. By using paired t-test and ANOVA, the influence factors of vehicle operating characteristics are studied. The result shows that effects of ramp layout and mainline traffic environment on vehicle operation characteristics are significant. The regression model of vehicle traveling distance on acceleration lane is established. Suggestions are made for ramp entrance design of underground road.

Development and evaluation of RAMP I - a practitioner's tool for screening of musculoskeletal disorder risk factors in manual handling.

PubMed

Lind, Carl Mikael; Forsman, Mikael; Rose, Linda Maria

2017-10-16

RAMP I is a screening tool developed to support practitioners in screening for work-related musculoskeletal disorder risk factors related to manual handling. RAMP I, which is part of the RAMP tool, is based on research-based studies combined with expert group judgments. More than 80 practitioners participated in the development of RAMP I. The tool consists of dichotomous assessment items grouped into seven categories. Acceptable reliability was found for a majority of the assessment items for 15 practitioners who were given 1 h of training. The usability evaluation points to RAMP I being usable for screening for musculoskeletal disorder risk factors, i.e., usable for assessing risks, being usable as a decision base, having clear results and that the time needed for an assessment is acceptable. It is concluded that RAMP I is a usable tool for practitioners.

Effects of ramp reset pulses on the address discharge in a shadow mask plasma display panel

NASA Astrophysics Data System (ADS)

Yang, Lanlan; Tu, Yan; Zhang, Xiong; Jiang, Youyan; Zhang, Jian; Wang, Baoping

2007-05-01

A two-dimensional self-consistent numerical simulation model is used to analyse the effects of the ramp reset pulses on the address discharge in a shadow mask plasma display panel (SM-PDP). Some basic parameters such as the slope of the ramp pulse and the terminal voltage of the ramp reset period are varied to investigate their effects. The simulation results illustrate that the wall voltage is mainly decided by the terminal voltage and the firing voltage at the end of the ramp reset period. Moreover, the variation of the ramp slope will also bring a few modifications to the wall voltage. The priming particles in the beginning of the addressing period are related to the slope of the ramping down voltage pulse. The simulation results can help us optimize the driving scheme of the SM-PDP.

A microfluidic separation platform using an array of slanted ramps

NASA Astrophysics Data System (ADS)

Risbud, Sumedh; Bernate, Jorge; Drazer, German

2013-03-01

The separation of the different components of a sample is a crucial step in many micro- and nano-fluidic applications, including the detection of infections, the capture of circulating tumor cells, the isolation of proteins, RNA and DNA, to mention but a few. Vector chromatography, in which different species migrate in different directions in a planar microfluidic device thus achieving spatial as well as temporal resolution, offers the promise of high selectivity along with high throughput. In this work, we present a microfluidic vector chromatography platform consisting of slanted ramps in a microfluidic channel for the separation of suspended particles. We construct these ramps using inclined UV lithography, such that the inclined portion of the ramps is upstream. We show that particles of different size displace laterally to a different extent when driven by a flow field over a slanted ramp. The flow close to the ramp reorients along the ramp, causing the size-dependent deflection of the particles. The cumulative effect of an array of these ramps would cause particles of different size to migrate in different directions, thus allowing their passive and continuous separation.

Experiments and modelling of rate-dependent transition delay in a stochastic subcritical bifurcation

NASA Astrophysics Data System (ADS)

Bonciolini, Giacomo; Ebi, Dominik; Boujo, Edouard; Noiray, Nicolas

2018-03-01

Complex systems exhibiting critical transitions when one of their governing parameters varies are ubiquitous in nature and in engineering applications. Despite a vast literature focusing on this topic, there are few studies dealing with the effect of the rate of change of the bifurcation parameter on the tipping points. In this work, we consider a subcritical stochastic Hopf bifurcation under two scenarios: the bifurcation parameter is first changed in a quasi-steady manner and then, with a finite ramping rate. In the latter case, a rate-dependent bifurcation delay is observed and exemplified experimentally using a thermoacoustic instability in a combustion chamber. This delay increases with the rate of change. This leads to a state transition of larger amplitude compared with the one that would be experienced by the system with a quasi-steady change of the parameter. We also bring experimental evidence of a dynamic hysteresis caused by the bifurcation delay when the parameter is ramped back. A surrogate model is derived in order to predict the statistic of these delays and to scrutinize the underlying stochastic dynamics. Our study highlights the dramatic influence of a finite rate of change of bifurcation parameters upon tipping points, and it pinpoints the crucial need of considering this effect when investigating critical transitions.

Experiments and modelling of rate-dependent transition delay in a stochastic subcritical bifurcation

PubMed Central

Noiray, Nicolas

2018-01-01

Complex systems exhibiting critical transitions when one of their governing parameters varies are ubiquitous in nature and in engineering applications. Despite a vast literature focusing on this topic, there are few studies dealing with the effect of the rate of change of the bifurcation parameter on the tipping points. In this work, we consider a subcritical stochastic Hopf bifurcation under two scenarios: the bifurcation parameter is first changed in a quasi-steady manner and then, with a finite ramping rate. In the latter case, a rate-dependent bifurcation delay is observed and exemplified experimentally using a thermoacoustic instability in a combustion chamber. This delay increases with the rate of change. This leads to a state transition of larger amplitude compared with the one that would be experienced by the system with a quasi-steady change of the parameter. We also bring experimental evidence of a dynamic hysteresis caused by the bifurcation delay when the parameter is ramped back. A surrogate model is derived in order to predict the statistic of these delays and to scrutinize the underlying stochastic dynamics. Our study highlights the dramatic influence of a finite rate of change of bifurcation parameters upon tipping points, and it pinpoints the crucial need of considering this effect when investigating critical transitions. PMID:29657803

Modeling effectiveness of gradual increases in source level to mitigate effects of sonar on marine mammals.

PubMed

Von Benda-Beckmann, Alexander M; Wensveen, Paul J; Kvadsheim, Petter H; Lam, Frans-Peter A; Miller, Patrick J O; Tyack, Peter L; Ainslie, Michael A

2014-02-01

Ramp-up or soft-start procedures (i.e., gradual increase in the source level) are used to mitigate the effect of sonar sound on marine mammals, although no one to date has tested whether ramp-up procedures are effective at reducing the effect of sound on marine mammals. We investigated the effectiveness of ramp-up procedures in reducing the area within which changes in hearing thresholds can occur. We modeled the level of sound killer whales (Orcinus orca) were exposed to from a generic sonar operation preceded by different ramp-up schemes. In our model, ramp-up procedures reduced the risk of killer whales receiving sounds of sufficient intensity to affect their hearing. The effectiveness of the ramp-up procedure depended strongly on the assumed response threshold and differed with ramp-up duration, although extending the duration of the ramp up beyond 5 min did not add much to its predicted mitigating effect. The main factors that limited effectiveness of ramp up in a typical antisubmarine warfare scenario were high source level, rapid moving sonar source, and long silences between consecutive sonar transmissions. Our exposure modeling approach can be used to evaluate and optimize mitigation procedures. © 2013 Society for Conservation Biology.

Pressure ramp programmer; IMBLMS Phase B4 Additional Tasks: Task 3.0 pressure ramp programmer

NASA Technical Reports Server (NTRS)

Fogal, G. L.; Reinhardt, C. G.

1972-01-01

A pressure ramp programmer model was designed, fabricated and tested. This model, in conjunction with an automatic blood pressure monitor, automatically controls the pressure in the blood pressure monitor arterial cuff. The cuff pressurization cycle is designed to maximize accuracy and repeatability of blood pressure measurements. The key feature of this automatic cycle is rapid blood pressure cuff bleed down from an initial setting until systolic (diastolic) pressure is encountered followed by a short repressurization and slow bleed, long enough to permit accurate systolic (diastolic) pressure determination. The system includes a pressure reservoir which bleeds the cuff through a precision needle valve; a solenoid valve which permits rapid pressurization from the reservoir; and a pressure sensor which provides information for bleed rate and set point controls. Korotkoff sound signals from a microphone in the blood pressure cuff (not part of the system) provide decision information to the digital control system. The system completed a series of engineering tests using simulated Korotkoff sound inputs. The system performed successfully in all cases and was stable over an extended period of time.

Comparison of ventilation threshold and heart rate deflection point in fast and standard treadmill test protocols.

PubMed

Vucetić, Vlatko; Sentija, Davor; Sporis, Goran; Trajković, Nebojsa; Milanović, Zoran

2014-06-01

The purpose of this study was to compare two methods for determination of anaerobic threshold from two different treadmill protocols. Forty-eight Croatian runners of national rank (ten sprinters, fifteen 400-m runners, ten middle distance runners and thirteen long distance runners), mean age 21.7 +/- 5.1 years, participated in the study. They performed two graded maximal exercise tests on a treadmill, a standard ramp treadmill test (T(SR), speed increments of 1 km x h(-1) every 60 seconds) and a fast ramp treadmill test (T(FR), speed increments of 1 km x h(-1) every 30 seconds) to determine and compare the parameters at peak values and at heart rate at the deflection point (HR(DP)) and ventilation threshold (VT). There were no significant differences between protocols (p > 0.05) for peak values of oxygen uptake (VO(2max), 4.48 +/- 0.43 and 4.44 +/- 0.45 L x min(-1)), weight related VO(2max) (62.5 +/- 6.2 and 62.0 +/- 6.0 mL x kg(-1) x min(-1)), pulmonary ventilation (VE(max), 163.1 +/- 18.7 and 161.3 +/- 19.9 L x min(-1)) and heart rate (HR(max), 192.3 +/- 8.5 and 194.4 +/- 8.7 bpm) (T(FR) and T(SR), respectively). Moreover, no significant differences between T(FR) and T(SR) where found for VT and HR(DP) when expressed as VO2 and HR. However, there was a significant effect of ramp slope on running speed at VO(2max) and at the anaerobic threshold (AnT), independent of the method used (VT: 16.0 +/- 2.2 vs 14.9 +/- 2.2 km x h(-1);HR(DP): 16.5 +/- 1.9 vs 14.9 +/- 2.0 km x h(-1) for T(FR) and T(SR) respectively). Linear regression analysis revealed high between-test and between-method correlations for VO2, HR and running speed parameters (r = 0.78-0.89, p < 0.01). The present study has indicated that the VT and HR(DP) for running (VO2, ventilation, and heart rate at VT/HR(DP)) are independent of test protocol, while there is a significant effect of ramp slope on VT and HR(DP) when expressed as running speed. Moreover, this study demonstrates that the point of deflection from linearity of heart rate may be an accurate predictor of the anaerobic threshold in trained runners, independently of the protocol used.

Increasing The Electric Field For An Improved Search For Time-Reversal Violation Using Radium-225

NASA Astrophysics Data System (ADS)

Powers, Adam

2017-09-01

Radium-225 atoms, because of their unusual pear-shaped nuclei, have an enhanced sensitivity to the violation of time reversal symmetry. A breakdown of this fundamental symmetry could help explain the apparent scarcity of antimatter in the Universe. Our goal is to improve the statistical sensitivity of an ongoing experiment that precisely measures the EDM of Radium-225. This can be done by increasing the electric field acting on the Radium atoms. We do this by increasing the voltage that can be reliably applied between two electrodes, and narrowing the gap between them. We use a varying high voltage system to condition the electrodes using incremental voltage ramp tests to achieve higher voltage potential differences. Using an adjustable gap mount to change the distance between the electrodes, specific metals for their composition, and a clean room procedure to keep particulates out of the system, we produce a higher and more stable electric field. Progress is marked by measurements of the leakage current between the electrodes during our incremental voltage ramp tests or emulated tests of the actual experiment, with low and constant current showing stability of the field. This project is supported by Michigan State University, and the US DOE, Office of Science, Office of Nuclear Physics, under Contract DE-AC02-06CH11357.

18 CFR 5.6 - Pre-application document.

Code of Federal Regulations, 2011 CFR

2011-04-01

... project, including any daily or seasonal ramping rates, flushing flows, reservoir operations, and flood... document must describe the existing and proposed (if any) project facilities and operations, provide...)(viii). (2) Project location, facilities, and operations. The potential applicant must include in the...

Middle Eocene Nummulites and their offshore re-deposition: A case study from the Middle Eocene of the Venetian area, northeastern Italy

NASA Astrophysics Data System (ADS)

Bassi, Davide; Nebelsick, James H.; Puga-Bernabéu, Ángel; Luciani, Valeria

2013-11-01

The Middle Eocene Calcari nummulitici formation from northeastern Italy, Venetian area, represents a shallow-marine carbonate ramp developed on the northern Tethyan margin. In the Monti Berici area, its main components are larger foraminifera and coralline red algal communities that constitute thick carbonate sedimentary successions. Middle ramp and proximal outer ramp environments are recognized using component relationships, biofacies and sedimentary features. The middle-ramp is characterized by larger flattened-lenticular Nummulites on palaeohighs between which rhodoliths formed. Larger Nummulites palaeohighs containing Nummulites millecaput, Nummulites crassus, Nummulites discorbinus and Nummulites cf. gizehensis developed more basin-wards. The following relatively quiet environments of basin-wards of the palaeohighs represent areas of maximum carbonate production. The transition between the distal middle- and the proximal outer-ramp settings is marked in the study area by a large erosional surface which is interpreted to have been formed as a result of an erosive channel body filled in by deposits re-sedimented from shallower depths. These off-shore re-sedimented channelized deposits, ascribed to the Shallow Benthic Zone SBZ 15, lying on hemipelagic marls (planktonic foraminiferal zone E9 (P11)) allow for a biostratigraphic correlation to the Late Lutetian. The studied deposits, represented by packstone to rudstones, were displaced whilst still unlithified. The Lutetian-Bartonian regression along with the local tectonic activity promoted the production of a high amount of biogenic shallow-water carbonates mainly produced in the Mossano middle-ramp settings. These prograded towards the basinal areas with high-sedimentation rate of carbonate deposits characterized by the larger Nummulites rudstones. Such high amounts of sediment led to sediment instability which potentially could be mobilized either by return currents due to occasional major storms or by earthquakes induced by tectonic activity. These will have led to the offshore re-deposition of the Nummulites sediments into deeper water setting via the observed channels. Since potential migration pathways are short, such distal re-sedimented channel-filled material surrounded by hemipelagic marls is optimally placed for the formation of potential subsurface oil reservoirs.

Evaluation of the quality of care of a multi-disciplinary risk factor assessment and management programme (RAMP) for diabetic patients

PubMed Central

2012-01-01

Background Type 2 Diabetes Mellitus (DM) is a common chronic disease associated with multiple clinical complications. Management guidelines have been established which recommend a risk-stratified approach to managing these patients in primary care. This study aims to evaluate the quality of care (QOC) and effectiveness of a multi-disciplinary risk assessment and management programme (RAMP) for type 2 diabetic patients attending government-funded primary care clinics in Hong Kong. The evaluation will be conducted using a structured and comprehensive evidence-based evaluation framework. Method/design For evaluation of the quality of care, a longitudinal study will be conducted using the Action Learning and Audit Spiral methodologies to measure whether the pre-set target standards for criteria related to the structure and process of care are achieved. Each participating clinic will be invited to complete a Structure of Care Questionnaire evaluating pre-defined indicators which reflect the setting in which care is delivered, while process of care will be evaluated against the pre-defined indicators in the evaluation framework. Effectiveness of the programme will be evaluated in terms of clinical outcomes, service utilization outcomes, and patient-reported outcomes. A cohort study will be conducted on all eligible diabetic patients who have enrolled into RAMP for more than one year to compare their clinical and public service utilization outcomes of RAMP participants and non-participants. Clinical outcome measures will include HbA1c, blood pressure (both systolic and diastolic), lipids (low-density lipoprotein cholesterol) and future cardiovascular diseases risk prediction; and public health service utilization rate will include general and specialist outpatient, emergency department attendances, and hospital admissions annually within 5 years. For patient-reported outcomes, a total of 550 participants and another 550 non-participants will be followed by telephone to monitor quality of life, patient enablement, global rating of change in health and private health service utilization at baseline, 6, 12, 36 and 60 months. Discussion The quality of care and effectiveness of the RAMP in enhancing the health for patients with type 2 diabetes will be determined. Possible areas for quality enhancement will be identified and standards of good practice can be established. The information will be useful in guiding service planning and policy decision making. PMID:23216708

Evaluation of the quality of care of a multi-disciplinary risk factor assessment and management programme (RAMP) for diabetic patients.

PubMed

Fung, Colman S C; Chin, Weng Yee; Dai, Daisy S K; Kwok, Ruby L P; Tsui, Eva L H; Wan, Yuk Fai; Wong, Wendy; Wong, Carlos K H; Fong, Daniel Y T; Lam, Cindy L K

2012-12-05

Type 2 Diabetes Mellitus (DM) is a common chronic disease associated with multiple clinical complications. Management guidelines have been established which recommend a risk-stratified approach to managing these patients in primary care. This study aims to evaluate the quality of care (QOC) and effectiveness of a multi-disciplinary risk assessment and management programme (RAMP) for type 2 diabetic patients attending government-funded primary care clinics in Hong Kong. The evaluation will be conducted using a structured and comprehensive evidence-based evaluation framework. For evaluation of the quality of care, a longitudinal study will be conducted using the Action Learning and Audit Spiral methodologies to measure whether the pre-set target standards for criteria related to the structure and process of care are achieved. Each participating clinic will be invited to complete a Structure of Care Questionnaire evaluating pre-defined indicators which reflect the setting in which care is delivered, while process of care will be evaluated against the pre-defined indicators in the evaluation framework.Effectiveness of the programme will be evaluated in terms of clinical outcomes, service utilization outcomes, and patient-reported outcomes. A cohort study will be conducted on all eligible diabetic patients who have enrolled into RAMP for more than one year to compare their clinical and public service utilization outcomes of RAMP participants and non-participants. Clinical outcome measures will include HbA1c, blood pressure (both systolic and diastolic), lipids (low-density lipoprotein cholesterol) and future cardiovascular diseases risk prediction; and public health service utilization rate will include general and specialist outpatient, emergency department attendances, and hospital admissions annually within 5 years. For patient-reported outcomes, a total of 550 participants and another 550 non-participants will be followed by telephone to monitor quality of life, patient enablement, global rating of change in health and private health service utilization at baseline, 6, 12, 36 and 60 months. The quality of care and effectiveness of the RAMP in enhancing the health for patients with type 2 diabetes will be determined. Possible areas for quality enhancement will be identified and standards of good practice can be established. The information will be useful in guiding service planning and policy decision making.

LOX/Hydrocarbon Combustion Instability Investigation

NASA Technical Reports Server (NTRS)

Jensen, R. J.; Dodson, H. C.; Claflin, S. E.

1989-01-01

The LOX/Hydrocarbon Combustion Instability Investigation Program was structured to determine if the use of light hydrocarbon combustion fuels with liquid oxygen (LOX) produces combustion performance and stability behavior similar to the LOX/hydrogen propellant combination. In particular methane was investigated to determine if that fuel can be rated for combustion instability using the same techniques as previously used for LOX/hydrogen. These techniques included fuel temperature ramping and stability bomb tests. The hot fire program probed the combustion behavior of methane from ambient to subambient temperatures. Very interesting results were obtained from this program that have potential importance to future LOX/methane development programs. A very thorough and carefully reasoned documentation of the experimental data obtained is contained. The hot fire test logic and the associated tests are discussed. Subscale performance and stability rating testing was accomplished using 40,000 lb. thrust class hardware. Stability rating tests used both bombs and fuel temperature ramping techniques. The test program was successful in generating data for the evaluation of the methane stability characteristics relative to hydrogen and to anchor stability models. Data correlations, performance analysis, stability analyses, and key stability margin enhancement parameters are discussed.

Voltage-dependent formation of gramicidin channels in lipid bilayers.

PubMed Central

Sandblom, J; Galvanovskis, J; Jilderos, B

2001-01-01

The formation kinetics of gramicidin A channels in lipid bilayer membranes has been characterized as a function of voltage for different solution conditions and membrane composition. The frequency of channel events was measured during the application of voltage ramps and counted in given intervals, a procedure that eliminated the effects of drift in gramicidin concentration. The formation rate was found to increase strongly with voltages up to approximately 50 mV and then to level off slightly. The shape of the voltage dependence was independent of lipid solvent and ramp speed but differed for different ions and different solution concentrations. This suggested an ion occupancy effect on the formation rate that was further supported by the fact that the minimum of the formation rate was shifted toward the equilibrium potential in asymmetric solution concentrations. The effects are explained in terms of a model that contains two contributions to the voltage dependence, a voltage-dependent ion binding to the monomers and a polarization of monomers by the applied electric field and by the occupied ions. The theory is found to give a good fit to experimental data. PMID:11463628

40 CFR 1065.202 - Data updating, recording, and control.

Code of Federal Regulations, 2010 CFR

2010-07-01

... means. § 1065.514, § 1065.530 Steady-state and ramped-modal duty cycle reference and feedback speeds and... mean value per test interval. § 1065.530, § 1065.545 Diluted exhaust flow rate from a CVS with a heat exchanger upstream of the flow measurement N/A 1 Hz. § 1065.530, § 1065.545 Diluted exhaust flow rate from a...

Effect of current compliance and voltage sweep rate on the resistive switching of HfO{sub 2}/ITO/Invar structure as measured by conductive atomic force microscopy

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

Wu, You-Lin, E-mail: ylwu@ncnu.edu.tw; Liao, Chun-Wei; Ling, Jing-Jenn

2014-06-16

The electrical characterization of HfO{sub 2}/ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO{sub 2} surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO{sub 2}/ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates.more » It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.« less

A VCSEL based system for on-site monitoring of low level methane emission

NASA Astrophysics Data System (ADS)

Kannath, A.; Hodgkinson, J.; Gillard, R. G.; Riley, R. J.; Tatam, R. P.

2011-03-01

Continuous monitoring of methane emissions has assumed greater significance in the recent past due to increasing focus on global warming issues. Many industries have also identified the need for ppm level methane measurement as a means of gaining carbon credits. Conventional instruments based on NDIR spectroscopy are unable to offer the high selectivity and sensitivity required for such measurements. Here we discuss the development of a robust VCSEL based system for accurate low level measurements of methane. A possible area of application is the measurement of residual methane whilst monitoring the output of flare stacks and exhaust gases from methane combustion engines. The system employs a Wavelength Modulation Spectroscopy (WMS) scheme with second harmonic detection at 1651 nm. Optimum modulation frequency and ramp rates were chosen to maintain high resolution and fast response times which are vital for the intended application. Advanced data processing techniques were used to achieve long term sensitivity of the order of 10-5 in absorbance. The system is immune to cross interference from other gases and its inherent design features makes it ideal for large scale commercial production. The instrument maintains its calibration and offers a completely automated continuous monitoring solution for remote on site deployment.

Comprehensive School Counseling Programs and Student Achievement Outcomes: A Comparative Analysis of Ramp versus Non-Ramp Schools

ERIC Educational Resources Information Center

Wilkerson, Kevin; Perusse, Rachelle; Hughes, Ashley

2013-01-01

This study compares school-wide Annual Yearly Progress (AYP) results in Indiana schools earning the Recognized ASCA Model Program (RAMP) designation (n = 75) with a sample of control schools stratified by level and locale (n = 226). K-12 schools earning the RAMP designation in 2007, 2008, and 2009 comprise the experimental group. Findings indicate…

29 CFR 1918.86 - Roll-on roll-off (Ro-Ro) operations (see also § 1918.2, Ro-Ro operations, and § 1918.25).

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Ro-Ro operations, and § 1918.25). 9 [Reserved] (a) Traffic control system. An organized system of... simultaneous use of the ramp by vehicles and pedestrians. (d) Ramp maintenance. Ramps shall be properly...: (1) Sufficient power to ascend ramp inclines safely; and (2) Sufficient braking capacity to descend...

29 CFR 1918.86 - Roll-on roll-off (Ro-Ro) operations (see also § 1918.2, Ro-Ro operations, and § 1918.25).

Code of Federal Regulations, 2011 CFR

2011-07-01

... simultaneous use of the ramp by vehicles and pedestrians. (d) Ramp maintenance. Ramps shall be properly... ramp inclines safely. (j) Safe speeds. Power driven vehicles used in Ro-Ro operations shall be operated at speeds that are safe for prevailing conditions. (k) Ventilation. Internal combustion engine-driven...

Experimental Investigation of Transverse Supersonic Gaseous Injection Enhancement Into Supersonic Flow

DTIC Science & Technology

1996-12-01

Ramp AR 2........................................................ A.2 A. 9 . Test Section, No Injection or PME Ramp...B.2 B.8. Wide Ramp AR 1 ......................................................... B.2 B. 9 . Narrow Ramp AR 2...identified as a major near-field mixing factor.5 𔄀 While work has continued in transverse injection, 7𔄂 ’ 9 later studies sought to produce greater

Rover deployment system for lunar landing mission

NASA Astrophysics Data System (ADS)

Sutoh, Masataku; Hoshino, Takeshi; Wakabayashi, Sachiko

2017-09-01

For lunar surface exploration, a deployment system is necessary to allow a rover to leave the lander. The system should be as lightweight as possible and stored retracted when launched. In this paper, two types of retractable deployment systems for lunar landing missions, telescopic- and fold-type ramps, are discussed. In the telescopic-type system, a ramp is stored with the sections overlapping and slides out during deployment. In the fold-type system, it is stored folded and unfolds for the deployment. For the development of these ramps, a design concept study and structural analysis were conducted first. Subsequently, ramp deployment and rover release tests were performed using the developed ramp prototypes. Through these tests, the validity of their design concepts and functions have been confirmed. In the rover release test, it was observed that the developed lightweight ramp was sufficiently strong for a 50-kg rover to descend. This result suggests that this ramp system is suitable for the deployment of a 300-kg-class rover on the Moon, where the gravity is about one-sixth that on Earth. The lightweight and sturdy ramp developed in this study will contribute to both safe rover deployment and increase of lander/rover payload.

Turning behaviors of T cells climbing up ramp-like structures are regulated by myosin light chain kinase activity and lamellipodia formation.

PubMed

Song, Kwang Hoon; Lee, Jaehyun; Jung, Hong-Ryul; Park, HyoungJun; Doh, Junsang

2017-09-14

T cells navigate diverse microenvironments to perform immune responses. Micro-scale topographical structures within the tissues, which may inherently exist in normal tissues or may be formed by inflammation or injury, can influence T cell migration, but how T cell migration is affected by such topographical structures have not been investigated. In this study, we fabricated ramp-like structures with a 5 μm height and various slopes, and observed T cells climbing up the ramp-like structures. T cells encountering the ramp-like structures exhibited MLC accumulation near head-tail junctions contacting the ramp-like structures, and made turns to the direction perpendicular to the ramp-like structures. Pharmacological study revealed that lamellipodia formation mediated by arp2/3 and contractility regulated by myosin light chain kinase (MLCK) were responsible for the intriguing turning behavior of T cells climbing the ramp-like structures. Arp2/3 or MLCK inhibition substantially reduced probability of T cells climbing sharp-edged ramp-like structures, indicating intriguing turning behavior of T cells mediated by lamellipodia formation and MLCK activity may be important for T cells to access inflamed or injured tissues with abrupt topographical changes.

Haploinsufficiency for Adrenomedullin Reduces Pinopodes and Diminishes Uterine Receptivity in Mice1

PubMed Central

Li, Manyu; Wu, Yongqin; Caron, Kathleen M.

2008-01-01

Adrenomedullin (AM) is a multifunctional peptide vasodilator that signals through a G-protein-coupled receptor when the receptor, called calcitonin receptor-like receptor (CL), is associated with a receptor activity-modifying protein 2 (RAMP2). We demonstrated previously that haploinsufficieny for each of these genes led to reduced maternal fertility, and that even a modest genetic reduction of AM peptide caused maternal defects in implantation, placentation, and fetal growth. Here, we further demonstrate that Adm+/− female mice displayed reduced pregnancy success rates that were not caused by defects in folliculogenesis, ovulation, or fertilization. The poor fertility of Adm+/− female mice could not be rescued by transfer of wild-type blastocysts, which suggested an underlying defect in uterine receptivity. In fact, we found that Adm, Calcrl, and Ramp2 gene expressions are tightly and spatiotemporally regulated in the luminal epithelial cells of the uterus during the estrus cycle and the peri-implantation period. RAMP3, which also generates an AM receptor when associated with CL, had a diametrically opposite expression pattern than that of Adm, Calcrl, and Ramp2 and was most robustly induced in the stroma of the uterus. Finally, we discovered that Adm+/− female mice have a substantially reduced number of pinopodes on the uterine luminal epithelial surface, which is indicative and possibly causative of the poor uterine receptivity. Taken together, our studies identify a new class of pharmacologically tractable proteins that are involved in establishing uterine receptivity through the regulation of pinopode formation. PMID:18716289

Terasaki Spiral Ramps in the Rough Endoplasmic Reticulum

NASA Astrophysics Data System (ADS)

Guven, Jemal; Huber, Greg; Valencia, Dulce María

2014-10-01

We present a model describing the morphology as well as the assembly of "Terasaki ramps," the recently discovered helicoidal connections linking adjacent sheets of the rough endoplasmic reticulum (ER). The fundamental unit is a localized symmetric double-ramped "parking garage" formed by two separated gently pitched, approximately helicoidal, ramps of opposite chiralities. This geometry is stabilized by a short-range repulsive interaction between ramps associated with bending energy which opposes the long-range attraction associated with tension. The ramp inner boundaries are themselves stabilized by the condensation of membrane-shaping proteins along their length. A mechanism for parking garage self-assembly is proposed involving the nucleation of dipoles at the center of tubular three-way junctions within the smooth ER. Our predictions are compared with the experimental data.

Use of a complete starter feed in grain adaptation programs for feedlot cattle.

PubMed

Schneider, C J; Nuttelman, B L; Shreck, A L; Burken, D B; Griffin, W A; Gramkow, J L; Stock, R A; Klopfenstein, T J; Erickson, G E

2017-08-01

Four experiments evaluated the use of a complete starter feed (RAMP; Cargill Corn Milling, Blair, NE) for grain adaptation. In Exp. 1, 229 yearling steers (397 ± 28.4 kg BW) were used to compare a traditional adaptation program (CON) with adapting cattle with RAMP in either a 1- (RAMP-1RS) or 2- (RAMP-2RS) ration system. From d 23 to slaughter, cattle were fed a common finishing diet. In Exp. 2, 390 yearling steers (341 ± 14 kg BW) were used to compare accelerated grain adaptation programs with RAMP with 2 control treatments where RAMP was blended with a finishing diet containing either 25 (CON25) or 47.5% (CON47) Sweet Bran (Cargill Corn Milling) in 4 steps fed over 24 d to adapt cattle. Rapid adaptation treatments involved feeding RAMP for 10 d followed by a blend of RAMP and a 47% Sweet Bran finishing diet to transition cattle with 3 blends fed for 1 d each (3-1d), 2 blends fed for 2 d each (2-2d), or 1 blend fed for 4 d (1-4d). From d 29 to slaughter, all cattle were fed a common finishing diet. In Exp. 3, 300 steer calves (292 ± 21 kg BW) were used to compare the CON47 and 1-4d adaptation programs with directly transitioning cattle from RAMP, which involved feeding RAMP for 10 d and then switching directly to F1 on d 11 (1-STEP). From d 29 until slaughter, F2 was fed to all cattle. In Exp. 4, 7 ruminally fistulated steers (482 ± 49 kg BW) were used in a 35-d trial to compare the CON47 and 1-STEP adaptation programs. Ruminal pH and intake data from the first 6 d of F1and first 6 d of F2 were used to compare adaptation systems. Adaptation with RAMP-1RS and RAMP-2RS increased ( < 0.01) G:F compared with cattle adapted using CON in Exp. 1. Feeding RAMP-1RS increased ADG ( = 0.03) compared with CON. Intakes were similar ( = 0.39) among treatments. Daily gain, DMI, G:F, and carcass traits were similar ( > 0.11) among treatments in Exp. 2. Daily gain, DMI, and G:F were not different ( > 0.20) among treatments on d 39 or over the entire feeding period in Exp. 3. When F1 or F2 was being fed, DMI was similar ( ≥ 0.40) for CON47 and 1-STEP in Exp. 4. When F1 or F2 was being fed, 1-STEP cattle had lower average ruminal pH ( ≤ 0.03) and greater time below a pH of 5.3 ( ≤ 0.03). Using RAMP for grain adaptation improved performance compared with traditional adaptation. Rapid adaptation with RAMP decreased pH, but no performance differences were observed between long and rapid RAMP adaptation programs. Therefore, cattle started on RAMP do not require extensive adaptation before feeding a finishing diet with Sweet Bran.

Mixed Linear/Square-Root Encoded Single Slope Ramp Provides a Fast, Low Noise Analog to Digital Converter with Very High Linearity for Focal Plane Arrays

NASA Technical Reports Server (NTRS)

Wrigley, Christopher James (Inventor); Hancock, Bruce R. (Inventor); Cunningham, Thomas J. (Inventor); Newton, Kenneth W. (Inventor)

2014-01-01

An analog-to-digital converter (ADC) converts pixel voltages from a CMOS image into a digital output. A voltage ramp generator generates a voltage ramp that has a linear first portion and a non-linear second portion. A digital output generator generates a digital output based on the voltage ramp, the pixel voltages, and comparator output from an array of comparators that compare the voltage ramp to the pixel voltages. A return lookup table linearizes the digital output values.

Launch of a Vehicle from a Ramp

ERIC Educational Resources Information Center

Cross, Rod

2011-01-01

A vehicle proceeding up an inclined ramp will become airborne if the ramp comes to a sudden end and if the vehicle fails to stop before it reaches the end of the ramp. A vehicle may also become airborne if it passes over the top of a hill at sufficient speed. In both cases, the vehicle becomes airborne if the point of support underneath the…

29 CFR 1918.86 - Roll-on roll-off (Ro-Ro) operations (see also § 1918.2, Ro-Ro operations, and § 1918.25).

Code of Federal Regulations, 2014 CFR

2014-07-01

..., Ro-Ro operations, and § 1918.25). 9 [Reserved] (a) Traffic control system. An organized system of vehicular and pedestrian traffic control shall be established and maintained at each entrance/exit ramp and on ramps within the vessel as traffic flow warrants. (b) Ramp load limit. Each ramp shall be plainly...

29 CFR 1918.86 - Roll-on roll-off (Ro-Ro) operations (see also § 1918.2, Ro-Ro operations, and § 1918.25).

Code of Federal Regulations, 2012 CFR

2012-07-01

..., Ro-Ro operations, and § 1918.25). 9 [Reserved] (a) Traffic control system. An organized system of vehicular and pedestrian traffic control shall be established and maintained at each entrance/exit ramp and on ramps within the vessel as traffic flow warrants. (b) Ramp load limit. Each ramp shall be plainly...

29 CFR 1918.86 - Roll-on roll-off (Ro-Ro) operations (see also § 1918.2, Ro-Ro operations, and § 1918.25).

Code of Federal Regulations, 2013 CFR

2013-07-01

..., Ro-Ro operations, and § 1918.25). 9 [Reserved] (a) Traffic control system. An organized system of vehicular and pedestrian traffic control shall be established and maintained at each entrance/exit ramp and on ramps within the vessel as traffic flow warrants. (b) Ramp load limit. Each ramp shall be plainly...

The quasi-equilibrium response of MOS structures: Quasi-static factor

NASA Astrophysics Data System (ADS)

Okeke, M.; Balland, B.

1984-07-01

The dynamic response of a MOS structure driven into a non-equilibrium behaviour by a voltage ramp is presented. In contrast to Khun's quasi-static technique it is shown that any ramp-driven MOS structure has some degree of non-equilibrium. A quasi staticity factor μAK which serves as a measure of the degree of quasi-equilibrium, has been introduced for the first time. The mathematical model presented in the paper allows a better explanation of the experimental recordings. It is shown that this model could be used to analyse the various features of the response of the structure and that such physical parameters as the generation-rate, trap activation energy, and the effective capture constants could be obtained.

Numerical study of supersonic combustors by multi-block grids with mismatched interfaces

NASA Technical Reports Server (NTRS)

Moon, Young J.

1990-01-01

A three dimensional, finite rate chemistry, Navier-Stokes code was extended to a multi-block code with mismatched interface for practical calculations of supersonic combustors. To ensure global conservation, a conservative algorithm was used for the treatment of mismatched interfaces. The extended code was checked against one test case, i.e., a generic supersonic combustor with transverse fuel injection, examining solution accuracy, convergence, and local mass flux error. After testing, the code was used to simulate the chemically reacting flow fields in a scramjet combustor with parallel fuel injectors (unswept and swept ramps). Computational results were compared with experimental shadowgraph and pressure measurements. Fuel-air mixing characteristics of the unswept and swept ramps were compared and investigated.

Evidence for Conservation of the Calcitonin Superfamily and Activity-regulating Mechanisms in the Basal Chordate Branchiostoma floridae: INSIGHTS INTO THE MOLECULAR AND FUNCTIONAL EVOLUTION IN CHORDATES.

PubMed

Sekiguchi, Toshio; Kuwasako, Kenji; Ogasawara, Michio; Takahashi, Hiroki; Matsubara, Shin; Osugi, Tomohiro; Muramatsu, Ikunobu; Sasayama, Yuichi; Suzuki, Nobuo; Satake, Honoo

2016-01-29

The calcitonin (CT)/CT gene-related peptide (CGRP) family is conserved in vertebrates. The activities of this peptide family are regulated by a combination of two receptors, namely the calcitonin receptor (CTR) and the CTR-like receptor (CLR), and three receptor activity-modifying proteins (RAMPs). Furthermore, RAMPs act as escort proteins by translocating CLR to the cell membrane. Recently, CT/CGRP family peptides have been identified or inferred in several invertebrates. However, the molecular characteristics and relevant functions of the CTR/CLR and RAMPs in invertebrates remain unclear. In this study, we identified three CT/CGRP family peptides (Bf-CTFPs), one CTR/CLR-like receptor (Bf-CTFP-R), and three RAMP-like proteins (Bf-RAMP-LPs) in the basal chordate amphioxus (Branchiostoma floridae). The Bf-CTFPs were shown to possess an N-terminal circular region typical of the CT/CGRP family and a C-terminal Pro-NH2. The Bf-CTFP genes were expressed in the central nervous system and in endocrine cells of the midgut, indicating that Bf-CTFPs serve as brain and/or gut peptides. Cell surface expression of the Bf-CTFP-R was enhanced by co-expression with each Bf-RAMP-LP. Furthermore, Bf-CTFPs activated Bf-CTFP-R·Bf-RAMP-LP complexes, resulting in cAMP accumulation. These results confirmed that Bf-RAMP-LPs, like vertebrate RAMPs, are prerequisites for the function and translocation of the Bf-CTFP-R. The relative potencies of the three peptides at each receptor were similar. Bf-CTFP2 was a potent ligand at all receptors in cAMP assays. Bf-RAMP-LP effects on ligand potency order were distinct to vertebrate CGRP/adrenomedullin/amylin receptors. To the best of our knowledge, this is the first molecular and functional characterization of an authentic invertebrate CT/CGRP family receptor and RAMPs. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Possibilities of fish passage through the block ramp: Model-based estimation of permeability.

PubMed

Plesiński, Karol; Bylak, Aneta; Radecki-Pawlik, Artur; Mikołajczyk, Tomasz; Kukuła, Krzysztof

2018-08-01

Block ramps offer an opportunity to combine hydrotechnical structures with fish passages. The primary study objective was to evaluate the effectiveness of a block ramp for upstream fish movement in a mountain stream. Geodetic measurements of the bottom surface and water level were taken for three cross-sections. The description of the geometric and hydrodynamic parameters of the block ramp was supplemented with information on the width and length of crevices between boulders. Measurements of the geometric and hydrodynamic parameters of the block ramp were performed at 76 measurement sites, at three different types of discharge. Ichthyological data were collected in the analyzed stream. Measurements covered among others total length, width, and height of caught fish. Salmonid, cottid, balitorid, and cyprinid fish were studied. The determination of the main effects of the geometric and hydrodynamic parameters of the block ramp on the possibilities of use by target fish species employed generalized linear models (GLMs). The study shows that the block ramp cannot provide longitudinal connectivity and migration of fish occurring in the mountain stream. According to estimates, the block ramp did not meet the permeability expectations. The reason for low usefulness of the ramp for fish is particularly excessively strong water current. The stream concentration constituted an unsurmountable velocity barrier for fish moving upstream for each of the analyzed discharges. The developed model suggests that some crevices in the side zones of the ramp could be parts of the migration corridor, but only for small and medium-sized fish. At medium and high water stages, movement of fish in crevices was difficult due to fast water current, and at low and very low discharges, some crevices lost their permeability, and could become ecological traps for fish. The necessity of estimation of ramp permeability during pre-construction phase was emphasized. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of seasonal acclimatization on temperature dependence of cardiac excitability in the roach, Rutilus rutilus.

PubMed

Badr, A; El-Sayed, M F; Vornanen, M

2016-05-15

Temperature sensitivity of electrical excitability is a potential limiting factor for performance level and thermal tolerance of excitable tissues in ectothermic animals. To test whether the rate and rhythm of the heart acclimatize to seasonal temperature changes, thermal sensitivity of cardiac excitation in a eurythermal teleost, the roach (Rutilus rutilus), was examined. Excitability of the heart was determined from in vivo electrocardiograms and in vitro microelectrode recordings of action potentials (APs) from winter and summer roach acclimatized to 4 and 18°C, respectively. Under heat ramps (3°C h(-1)), starting from the acclimatization temperatures of the fish, heart rate increased to maximum values of 78±5 beats min(-1) (at 19.8±0.5°C) and 150±7 beats min(-1) (at 28.1±0.5°C) for winter and summer roach, respectively, and then declined in both groups. Below 20°C, heart rate was significantly higher in winter than in summer roach (P<0.05), indicating positive thermal compensation. Cardiac arrhythmias appeared with rising temperature as missing QRS complexes, increase in variability of heart rate, episodes of atrial tachycardia, ventricular bradycardia and complete cessation of the heartbeat (asystole) in both winter and summer roach. Unlike winter roach, atrial APs of summer roach had a distinct early repolarization phase, which appeared as shorter durations of atrial AP at 10% and 20% repolarization levels in comparison to winter roach (P<0.05). In contrast, seasonal acclimatization had only subtle effects on ventricular AP characteristics. Plasticity of cardiac excitation appears to be necessary for seasonal improvements in performance level and thermal resilience of the roach heart. © 2016. Published by The Company of Biologists Ltd.

Operational Impacts of Wind Energy Resources in the Bonneville Power Administration Control Area - Phase I Report

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

Makarov, Yuri V.; Lu, Shuai

2008-07-15

This report presents a methodology developed to study the future impact of wind on BPA power system load following and regulation requirements. The methodology uses historical data and stochastic processes to simulate the load balancing processes in the BPA power system, by mimicking the actual power system operations. Therefore, the results are close to reality, yet the study based on this methodology is convenient to conduct. Compared with the proposed methodology, existing methodologies for doing similar analysis include dispatch model simulation and standard deviation evaluation on load and wind data. Dispatch model simulation is constrained by the design of themore » dispatch program, and standard deviation evaluation is artificial in separating the load following and regulation requirements, both of which usually do not reflect actual operational practice. The methodology used in this study provides not only capacity requirement information, it also analyzes the ramp rate requirements for system load following and regulation processes. The ramp rate data can be used to evaluate generator response/maneuverability requirements, which is another necessary capability of the generation fleet for the smooth integration of wind energy. The study results are presented in an innovative way such that the increased generation capacity or ramp requirements are compared for two different years, across 24 hours a day. Therefore, the impact of different levels of wind energy on generation requirements at different times can be easily visualized.« less

Optimization of pressure settings during adaptive servo-ventilation support using real-time heart rate variability assessment: initial case report.

PubMed

Imamura, Teruhiko; Nitta, Daisuke; Kinugawa, Koichiro

2017-01-05

Adaptive servo-ventilation (ASV) therapy is a recent non-invasive positive pressure ventilation therapy that was developed for patients with heart failure (HF) refractory to optimal medical therapy. However, it is likely that ASV therapy at relatively higher pressure setting worsens some of the patients' prognosis compared with optimal medical therapy. Therefore, identification of optimal pressure settings of ASV therapy is warranted. We present the case of a 42-year-old male with HF, which was caused by dilated cardiomyopathy, who was admitted to our institution for evaluating his eligibility for heart transplantation. To identify the optimal pressure setting [peak end-expiratory pressure (PEEP) ramp test], we performed an ASV support test, during which the PEEP settings were set at levels ranging from 4 to 8 mmHg, and a heart rate variability (HRV) analysis using the MemCalc power spectral density method. Clinical parameters varied dramatically during the PEEP ramp test. Over incremental PEEP levels, pulmonary capillary wedge pressure, cardiac index and high-frequency level (reflecting parasympathetic activity) decreased; however, the low-frequency level increased along with increase in plasma noradrenaline concentrations. An inappropriately high PEEP setting may stimulate sympathetic nerve activity accompanied by decreased cardiac output. This was the first report on the PEEP ramp test during ASV therapy. Further research is warranted to determine whether use of optimal pressure settings using HRV analyses may improve the long-term prognosis of such patients.

Freeway ramp management in Pennsylvania.

DOT National Transportation Integrated Search

2011-03-31

This research identified the opportunities to implement ramp management strategies on freeways in Pennsylvania. The research : explored the need to integrate local arterial traffic signal systems with ramp management strategies to reduce the impacts ...

Lateral ramps in the folded Appalachians and in overthrust belts worldwide; a fundamental element of thrust-belt architecture

USGS Publications Warehouse

Pohn, Howard A.

2000-01-01

Lateral ramps are zones where decollements change stratigraphic level along strike; they differ from frontal ramps, which are zones where decollements change stratigraphic level perpendicular to strike. In the Appalachian Mountains, the surface criteria for recognizing the subsurface presence of lateral ramps include (1) an abrupt change in wavelength or a termination of folds along strike, (2) a conspicuous change in the frequency of mapped faults or disturbed zones (extremely disrupted duplexes) at the surface, (3) long, straight river trends emerging onto the coastal plain or into the Appalachian Plateaus province, (4) major geomorphic discontinuities in the trend of the Blue Ridge province, (5) interruption of Mesozoic basins by cross-strike border faults, and (6) zones of modern and probable ancient seismic activity. Additional features related to lateral ramps include tectonic windows, cross-strike igneous intrusions, areas of giant landslides, and abrupt changes in Paleozoic sedimentation along strike. Proprietary strike-line seismic-reflection profiles cross three of the lateral ramps that were identified by using the surface criteria. The profiles confirm their presence and show their detailed nature in the subsurface. Like frontal ramps, lateral ramps are one of two possible consequences of fold-and-thrust-belt tectonics and are common elements in the Appalachian fold-and-thrust belt. A survey of other thrust belts in the United States and elsewhere strongly suggests that lateral ramps at depth can be identified by their surface effects. Lateral ramps probably are the result of thrust sheet motion caused by continued activation of ancient cratonic fracture systems. Such fractures localized the transform faults along which the continental segments adjusted during episodes of sea-floor spreading.

Multifunctional overcoats on vanadium dioxide thermochromic thin films with enhanced luminous transmission and solar modulation, hydrophobicity and anti-oxidation

NASA Astrophysics Data System (ADS)

Liu, Chang; Wang, Ning; Long, Yi

2013-10-01

Vanadium dioxide (VO2) has a great potential to be utilized as solar energy switching glazing, even though there exist some intrinsic problems of low luminous transmittance (Tlum) and poor oxidation resistance. Si-Al based anti-reflection (AR) sol-gel coatings processed at low temperature have been developed to tackle these issues assisted by adjusting ramping rate and annealing temperature. Si-Al based AR coating gives large relative enhancement on the transmittance (22% for Tlum, 14% for the whole solar spectrum Tsol,) and successfully maintains IR contrast at 2500 nm wavelength with 18% relative increase in solar modulation (ΔTsol). The optimized Si-Al based AR coating annealing conditions are recorded at 3 °C/min ramping rate and 100 °C annealing temperature. Fluorinated-Si based gel offers a new direction of multifunctional overcoat on thermochromic smart windows with hydrophobicity (contact angle 111°), averaged 14% relatively increased luminous transmittance and enhanced oxidation resistance.

Isentropic compression of liquid metals near the melt line

NASA Astrophysics Data System (ADS)

Seagle, Christopher; Porwitzky, Andrew

2017-06-01

A series of experiments designed to study the liquid metal response to isentropic compression have been conducted at Sandia's Z Pulsed Power Facility. Cerium and Tin have been shock melted by driving a quasi-ballistic flyer into the samples followed by a ramp compression wave generated by an increased driving magnetic field. The sound speed of the liquid metals has been investigated with the purpose of exploring possible solidification on ramp compression. Additional surface sensitive diagnostics have been employed to search for signatures of solidification at the window interface. Results of these experiments will be discussed in relation to the existing equation of state models and phase diagrams for these materials as well as future plans for exploring the response of liquid metals near the melt line. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Analytic descriptions of stochastic bistable systems under force ramp

DOE PAGES

Friddle, Raymond W.

2016-05-13

Solving the two-state master equation with time-dependent rates, the ubiquitous driven bistable system, is a long-standing problem that does not permit a complete solution for all driving rates. We show an accurate approximation to this problem by considering the system in the control parameter regime. Moreover, the results are immediately applicable to a diverse range of bistable systems including single-molecule mechanics.

Study on Trailing Edge Ramp of Supercritical Airfoil

DTIC Science & Technology

2016-03-30

7 th Asia-Pacific International Symposium on Aerospace Technology, 25 – 27 November 2015, Cairns Study on Trailing Edge Ramp of Supercritical...China Abstract Trailing edge flow control method could improve the performance of supercritical airfoil with a small modification on the original...airfoil. In this paper, a ramp of 2%~7% chord length is sliced near the trailing edge to improve airfoil performance. The trailing edge ramp is

Wind-Friendly Flexible Ramping Product Design in Multi-Timescale Power System Operations

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

Cui, Mingjian; Zhang, Jie; Wu, Hongyu

With increasing wind power penetration in the electricity grid, system operators are recognizing the need for additional flexibility, and some are implementing new ramping products as a type of ancillary service. However, wind is generally thought of as causing the need for ramping services, not as being a potential source for the service. In this paper, a multi-timescale unit commitment and economic dispatch model is developed to consider the wind power ramping product (WPRP). An optimized swinging door algorithm with dynamic programming is applied to identify and forecast wind power ramps (WPRs). Designed as positive characteristics of WPRs, the WPRPmore » is then integrated into the multi-timescale dispatch model that considers new objective functions, ramping capacity limits, active power limits, and flexible ramping requirements. Numerical simulations on the modified IEEE 118-bus system show the potential effectiveness of WPRP in increasing the economic efficiency of power system operations with high levels of wind power penetration. It is found that WPRP not only reduces the production cost by using less ramping reserves scheduled by conventional generators, but also possibly enhances the reliability of power system operations. Moreover, wind power forecasts play an important role in providing high-quality WPRP service.« less

Use of Ramped PyrOx 14C dating to simultaneously determine the organic carbon age and carbonate material age of Antarctic marginal sediments

NASA Astrophysics Data System (ADS)

Reese, D.; DeCesare, M.; Subt, C.; Bart, P. J.; Wellner, J. S.; Rosenheim, B. E.

2016-12-01

Chronicling deglaciation rates and style in Antarctic margin sediment is difficult because of low preservation/deposition of carbonate foraminiferal tests as well as incorporation of pre-aged organic carbon from carbonaceous rocks. When carbonates for radiocarbon dating are absent, acid-insoluble organic matter (AIOM) 14C dates are often used as an alternative and providing reliable chronologies in some locations. Results obtained by this method can cause difficulties such as false age reversals and ambiguity due to contamination with pre-aged carbon (Rosenheim et. al., 2008; Subt et al., 2016). Ramped PyrOx 14C dating has exploited the higher thermochemical stability of pre-aged carbon to separate carbon dating to the time of sediment deposition, and recently has produced chronologies similar to foraminifera-based chronologies (Subt et al., 2016). Samples for Ramped PyrOx 14C dating have generally been treated with acid to remove carbonates, and thus some acid soluble organic matter. In an effort to minimize the alteration of the organic matter, we apply Ramped PyrOx 14C dating to samples that have been both treated with 1N HCl and left untreated. Untreated samples display a characteristic large, sharp peak at higher temperatures than pyrolysis of organic matter that we interpret as carbonate decomposition. These carbonate decomposition peaks are characteristically sharp and occur at higher temperatures than the maximum evolution of CO2 from the organic matter in the sample. We isolated these peaks for comparison between known carbonate ages from picked foraminifera and low-temperature Ramped PyrOx splits from acid treated samples. We will discuss the treatment of the suite of 14C ages with reconciliation of two dating methods in mind. Ultimately, this approach offers promise for a single treatment of Antarctic margin sediments that provides chronologies from both carbonate and organic material.

Ramp meter design manual

DOT National Transportation Integrated Search

2000-01-01

Caltrans is committed to using ramp metering as an effective traffic management strategy to maintain an efficient freeway system and protect the investment made in constructing freeways by keeping them operating at or near capacity. Ramp Metering is ...

A tunable electron beam source using trapping of electrons in a density down-ramp in laser wakefield acceleration.

PubMed

Ekerfelt, Henrik; Hansson, Martin; Gallardo González, Isabel; Davoine, Xavier; Lundh, Olle

2017-09-25

One challenge in the development of laser wakefield accelerators is to demonstrate sufficient control and reproducibility of the parameters of the generated bunches of accelerated electrons. Here we report on a numerical study, where we demonstrate that trapping using density down-ramps allows for tuning of several electron bunch parameters by varying the properties of the density down-ramp. We show that the electron bunch length is determined by the difference in density before and after the ramp. Furthermore, the transverse emittance of the bunch is controlled by the steepness of the ramp. Finally, the amount of trapped charge depends both on the density difference and on the steepness of the ramp. We emphasize that both parameters of the density ramp are feasible to vary experimentally. We therefore conclude that this tunable electron accelerator makes it suitable for a wide range of applications, from those requiring short pulse length and low emittance, such as the free-electron lasers, to those requiring high-charge, large-emittance bunches to maximize betatron X-ray generation.

Flow control of micro-ramps on supersonic forward-facing step flow

NASA Astrophysics Data System (ADS)

Qing-Hu, Zhang; Tao, Zhu; Shihe, Yi; Anping, Wu

2016-05-01

The effects of the micro-ramps on supersonic turbulent flow over a forward-facing step (FFS) was experimentally investigated in a supersonic low-noise wind tunnel at Mach number 3 using nano-tracer planar laser scattering (NPLS) and particle image velocimetry (PIV) techniques. High spatiotemporal resolution images and velocity fields of supersonic flow over the testing model were captured. The fine structures and their spatial evolutionary characteristics without and with the micro-ramps were revealed and compared. The large-scale structures generated by the micro-ramps can survive the downstream FFS flowfield. The micro-ramps control on the flow separation and the separation shock unsteadiness was investigated by PIV results. With the micro-ramps, the reduction in the range of the reversal flow zone in streamwise direction is 50% and the turbulence intensity is also reduced. Moreover, the reduction in the average separated region and in separation shock unsteadiness are 47% and 26%, respectively. The results indicate that the micro-ramps are effective in reducing the flow separation and the separation shock unsteadiness. Project supported by the National Natural Science Foundation of China (Grant Nos. 11172326 and 11502280).

Relationship Factors Contributing to the Progression of Combat Related PTSD and Suicidality over Time

DTIC Science & Technology

2014-04-01

Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The RAMP project is designed to examine the key social context of intimate romantic...report is the “Relationships Among Military Personnel (RAMP) Project”. The RAMP project is designed to examine the key social context of intimate...making the RAMP Facebook page accessible (https://www.facebook.com/TheRAMPProject. As of March 1, 2014, 1531 individuals completed the eligibility

SEPARATED FLOW CONDITIONS AT PIPE WALLS OF WATER DISTRIBUTION MAINS - Project Summary

EPA Science Inventory

The objectives of this research project were to develop and evaluate a method for determining residence times for separated recirculation cavity flow conditions, and to determine the rate of growth and surface ramp contours developed from particulate deposits at obstacles that i...

The FCC Provides an Affordable On-Ramp.

ERIC Educational Resources Information Center

School Business Affairs, 1997

1997-01-01

In May 1997, the Federal Communications Commission provided funding and policies for implementing the Snow-Rockefeller-Exon-Kerrey Amendment of the Telecommunications Act of 1996. The amendment states that schools and libraries should have access to telecommunication services for educational purposes at discounted rates. This article explains the…

Delta wing vortex manipulation using pulsed and steady blowing during ramp pitching

NASA Technical Reports Server (NTRS)

Moreira, J.; Johari, H.

1995-01-01

The effectiveness of steady and pulsed blowing as a method of controlling delta wing vortices during ramp pitching has been investigated in flow visualization experiments conducted in a water tunnel. The recessed angled spanwise blowing technique was utilized for vortex manipulation. This technique was implemented on a beveled 60 delta wing using a pair of blowing ports located beneath the vortex core at 40% chord. The flow was injected primarily in the spanwise direction but was also composed of a component normal to the wing surface. The location of vortex burst was measured as a function of blowing intensity and pulsing frequency under static conditions, and the optimum blowing case was applied at three different wing pitching rates. Experimental results have shown that, when the burst location is upstream of the blowing port, pulsed blowing delays vortex breakdown in static and dynamic cases. Dynamic tests verified the existence of a hysteresis effect and demonstrated the improvements offered by pulsed blowing over both steady blowing and no-blowing scenarios. The application of blowing, at the optimum pulsing frequency, made the vortex breakdown location comparable in static and ramp pitch-up conditions.

Using high frequency consumption data to identify demand response potential for solar energy integration

NASA Astrophysics Data System (ADS)

Jin, L.; Borgeson, S.; Fredman, D.; Hans, L.; Spurlock, A.; Todd, A.

2015-12-01

California's renewable portfolio standard (2012) requires the state to get 33% of its electricity from renewable sources by 2020. Increased share of variable renewable sources such as solar and wind in the California electricity system may require more grid flexibility to insure reliable power services. Such grid flexibility can be potentially provided by changes in end use electricity consumptions in response to grid conditions (demand-response). In the solar case, residential consumption in the late afternoon can be used as reserve capacity to balance the drop in solar generation. This study presents our initial attempt to identify, from a behavior perspective, residential demand response potentials in relation to solar ramp events using a data-driven approach. Based on hourly residential energy consumption data, we derive representative daily load shapes focusing on discretionary consumption with an innovative clustering analysis technique. We aggregate the representative load shapes into behavior groups in terms of the timing and rhythm of energy use in the context of solar ramp events. Households of different behavior groups that are active during hours with high solar ramp rates are identified for capturing demand response potential. Insights into the nature and predictability of response to demand-response programs are provided.

A power-balance model for local helicity injection startup in a spherical tokamak

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

Barr, Jayson L.; Bongard, Michael W.; Burke, Marcus G.

A 0D circuit model for predicting I p( t) in Local Helicity Injection (LHI) discharges is developed. Analytic formulas for estimating the surface flux of finite-A plasmas developed are modified and expanded to treat highly shaped, ultralow-A tokamak geometry using a database of representative equilibria. Model predictions are compared to sample LHI discharges in the A ~ 1 Pegasus spherical tokamak, and are found to agree within 15% of experimental I p( t). High performance LHI discharges are found to follow the Taylor relaxation current limit for approximately the first half of the current ramp, or I p ≲ 75more » kA. The second half of the current ramp follows a limit imposed by power-balance as plasmas expand from high- A to ultralow- A. Here, this shape evolution generates a significant drop in external plasma inductance, effectively using the plasma’s initially high inductance to drive the current ramp and provide > 70% of the current drive V-s. Projections using this model indicate the relative influences of higher helicity input rate and injector current on the attainable total plasma current.« less

Floquet Engineering in Quantum Chains

NASA Astrophysics Data System (ADS)

Kennes, D. M.; de la Torre, A.; Ron, A.; Hsieh, D.; Millis, A. J.

2018-03-01

We consider a one-dimensional interacting spinless fermion model, which displays the well-known Luttinger liquid (LL) to charge density wave (CDW) transition as a function of the ratio between the strength of the interaction U and the hopping J . We subject this system to a spatially uniform drive which is ramped up over a finite time interval and becomes time periodic in the long-time limit. We show that by using a density matrix renormalization group approach formulated for infinite system sizes, we can access the large-time limit even when the drive induces finite heating. When both the initial and long-time states are in the gapless (LL) phase, the final state has power-law correlations for all ramp speeds. However, when the initial and final state are gapped (CDW phase), we find a pseudothermal state with an effective temperature that depends on the ramp rate, both for the Magnus regime in which the drive frequency is very large compared to other scales in the system and in the opposite limit where the drive frequency is less than the gap. Remarkably, quantum defects (instantons) appear when the drive tunes the system through the quantum critical point, in a realization of the Kibble-Zurek mechanism.

Thermodynamic Properties of Fast Ramped Superconducting Accelerator Magnets for the Fair Project

NASA Astrophysics Data System (ADS)

Fischer, E.; Mierau, A.; Schnizer, P.; Bleile, A.; Gärtner, W.; Guymenuk, O.; Khodzhibagiyan, H.; Schroeder, C.; Sikler, G.; Stafiniak, A.

2010-04-01

The 100 Tm synchrotron SIS 100 is the core component of the international Facility of Antiproton and Ion Research (FAIR) to be built at GSI Darmstadt. The 108 bending magnets are 3 m long 2 T superferric dipoles providing a nominal ramp rate of 4 T/s within a usable aperture of 115 mmṡ60 mm. An intensive R&D period was conducted to minimise the AC losses to lower operation costs and to guarantee a safe thermal stability for long term continuous cycling with a maximum repetition frequency of 1 Hz. The latter requirement is strictly limited by the overall heat flow originated by eddy currents and hysteresis losses in iron yoke and coil as well as by its hydraulic resistance respective to the forced two phase helium cooling flow within the hollow superconducting cable. Recently three full size dipoles—and one quadrupole magnets were built and intensive tests have been started in the end of 2008 at the GSI cryogenic test facility. We present the measured thermodynamic parameters of the first tested dipole: AC losses depending on Bmax and dB/dt for various characteristic ramping modes and conclude for necessary optimisations toward the final design of the series magnets.

A power-balance model for local helicity injection startup in a spherical tokamak

DOE PAGES

Barr, Jayson L.; Bongard, Michael W.; Burke, Marcus G.; ...

2018-05-15

A 0D circuit model for predicting I p( t) in Local Helicity Injection (LHI) discharges is developed. Analytic formulas for estimating the surface flux of finite-A plasmas developed are modified and expanded to treat highly shaped, ultralow-A tokamak geometry using a database of representative equilibria. Model predictions are compared to sample LHI discharges in the A ~ 1 Pegasus spherical tokamak, and are found to agree within 15% of experimental I p( t). High performance LHI discharges are found to follow the Taylor relaxation current limit for approximately the first half of the current ramp, or I p ≲ 75more » kA. The second half of the current ramp follows a limit imposed by power-balance as plasmas expand from high- A to ultralow- A. Here, this shape evolution generates a significant drop in external plasma inductance, effectively using the plasma’s initially high inductance to drive the current ramp and provide > 70% of the current drive V-s. Projections using this model indicate the relative influences of higher helicity input rate and injector current on the attainable total plasma current.« less

Effect of Valsartan on Cerebellar Adrenomedullin System Dysregulation During Hypertension.

PubMed

Figueira, Leticia; Israel, Anita

2017-02-01

Adrenomedullin (AM) and its receptors components, calcitonin-receptor-like receptor (CRLR), and receptor activity-modifying protein (RAMP1, RAMP2, and RAMP3) are expressed in cerebellum. Cerebellar AM, AM binding sites and receptor components are altered during hypertension, suggesting a role for cerebellar AM in blood pressure regulation. Thus, we assessed the effect of valsartan, on AM and its receptor components expression in the cerebellar vermis of Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Additionally, we evaluated AM action on superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activity, and thiobarbituric acid reactive substances (TBARS) production in cerebellar vermis. Animals were treated with valsartan or vehicle for 11 days. Rats were sacrificed by decapitation; cerebellar vermis was dissected; and AM, CRLR, RAMP1, RAMP2, and RAMP3 expression was quantified by Western blot analysis. CAT, SOD, and GPx activity was determined spectrophotometrically and blood pressure by non-invasive plethysmography. We demonstrate that AM and RAMP2 expression was lower in cerebellum of SHR rats, while CRLR, RAMP1, and RAMP3 expression was higher than those of WKY rats. AM reduced cerebellar CAT, SOD, GPx activities, and TBARS production in WKY rats, but not in SHR rats. Valsartan reduced blood pressure and reversed the altered expression of AM and its receptors components, as well the loss of AM capacity to reduce antioxidant enzyme activity and TBARS production in SHR rats. These findings demonstrate that valsartan is able to reverse the dysregulation of cerebellar adrenomedullinergic system; and they suggest that altered AM system in the cerebellum could represent the primary abnormality leading to hypertension.

Twin Cities ramp meter evaluation : executive summary

DOT National Transportation Integrated Search

2001-02-01

This report details the results of a study on the traffic flow and safety impacts of ramp metering. The study served two important public purposes. 1. It thoroughly documented the benefits resulting from ramp metering to traffic operations and relate...

Developing an area-wide system for coordinated ramp meter control.

DOT National Transportation Integrated Search

2008-12-01

Ramp metering has been broadly accepted and deployed as an effective countermeasure : against both recurrent and non-recurrent congestion on freeways. However, many current ramp : metering algorithms tend to improve only freeway travels using local d...

Facility No. S362, view across the ramp U.S. Naval ...

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

Facility No. S362, view across the ramp - U.S. Naval Base, Pearl Harbor, Seaplane Ramps - World War II Type, Southwest and west shore of Ford Island, near Wasp Boulevard, Pearl City, Honolulu County, HI

Congestion-Responsive On-Ramp Metering : Before and After Studies - Phase 1

DOT National Transportation Integrated Search

2016-07-06

The objective of this project was to develop recommendations toward a statewide policy of congestion responsive freeway ramp metering operation. The research is performed in two phases. In phase 1, alternative ramp metering activation strategies were...

Assessing the Effectiveness of Ramp-Up During Sonar Operations Using Exposure Models.

PubMed

von Benda-Beckmann, Alexander M; Wensveen, Paul J; Kvadsheim, Petter H; Lam, Frans-Peter A; Miller, Patrick J O; Tyack, Peter L; Ainslie, Michael A

2016-01-01

Ramp-up procedures are used to mitigate the impact of sound on marine mammals. Sound exposure models combined with observations of marine mammals responding to sound can be used to assess the effectiveness of ramp-up procedures. We found that ramp-up procedures before full-level sonar operations can reduce the risk of hearing threshold shifts with marine mammals, but their effectiveness depends strongly on the responsiveness of the animals. In this paper, we investigated the effect of sonar parameters (source level, pulse-repetition time, ship speed) on sound exposure by using a simple analytical model and highlight the mechanisms that limit the effectiveness of ramp-up procedures.

Improving short-term forecasting during ramp events by means of Regime-Switching Artificial Neural Networks

NASA Astrophysics Data System (ADS)

Gallego, C.; Costa, A.; Cuerva, A.

2010-09-01

Since nowadays wind energy can't be neither scheduled nor large-scale storaged, wind power forecasting has been useful to minimize the impact of wind fluctuations. In particular, short-term forecasting (characterised by prediction horizons from minutes to a few days) is currently required by energy producers (in a daily electricity market context) and the TSO's (in order to keep the stability/balance of an electrical system). Within the short-term background, time-series based models (i.e., statistical models) have shown a better performance than NWP models for horizons up to few hours. These models try to learn and replicate the dynamic shown by the time series of a certain variable. When considering the power output of wind farms, ramp events are usually observed, being characterized by a large positive gradient in the time series (ramp-up) or negative (ramp-down) during relatively short time periods (few hours). Ramp events may be motivated by many different causes, involving generally several spatial scales, since the large scale (fronts, low pressure systems) up to the local scale (wind turbine shut-down due to high wind speed, yaw misalignment due to fast changes of wind direction). Hence, the output power may show unexpected dynamics during ramp events depending on the underlying processes; consequently, traditional statistical models considering only one dynamic for the hole power time series may be inappropriate. This work proposes a Regime Switching (RS) model based on Artificial Neural Nets (ANN). The RS-ANN model gathers as many ANN's as different dynamics considered (called regimes); a certain ANN is selected so as to predict the output power, depending on the current regime. The current regime is on-line updated based on a gradient criteria, regarding the past two values of the output power. 3 Regimes are established, concerning ramp events: ramp-up, ramp-down and no-ramp regime. In order to assess the skillness of the proposed RS-ANN model, a single-ANN model (without regime classification) is adopted as a reference model. Both models are evaluated in terms of Improvement over Persistence on the Mean Square Error basis (IoP%) when predicting horizons form 1 time-step to 5. The case of a wind farm located in the complex terrain of Alaiz (north of Spain) has been considered. Three years of available power output data with a hourly resolution have been employed: two years for training and validation of the model and the last year for assessing the accuracy. Results showed that the RS-ANN overcame the single-ANN model for one step-ahead forecasts: the overall IoP% was up to 8.66% for the RS-ANN model (depending on the gradient criterion selected to consider the ramp regime triggered) and 6.16% for the single-ANN. However, both models showed similar accuracy for larger horizons. A locally-weighted evaluation during ramp events for one-step ahead was also performed. It was found that the IoP% during ramps-up increased from 17.60% (case of single-ANN) to 22.25% (case of RS-ANN); however, during the ramps-down events this improvement increased from 18.55% to 19.55%. Three main conclusions are derived from this case study: It highlights the importance of considering statistical models capable of differentiate several regimes showed by the output power time series in order to improve the forecasting during extreme events like ramps. On-line regime classification based on available power output data didn't seem to contribute to improve forecasts for horizons beyond one-step ahead. Tacking into account other explanatory variables (local wind measurements, NWP outputs) could lead to a better understanding of ramp events, improving the regime assessment also for further horizons. The RS-ANN model slightly overcame the single-ANN during ramp-down events. If further research reinforce this effect, special attention should be addressed to understand the underlying processes during ramp-down events.

RAMP2 Influences Glucagon Receptor Pharmacology via Trafficking and Signaling.

PubMed

Cegla, Jaimini; Jones, Ben J; Gardiner, James V; Hodson, David J; Marjot, Thomas; McGlone, Emma R; Tan, Tricia M; Bloom, Stephen R

2017-08-01

Endogenous satiety hormones provide an attractive target for obesity drugs. Glucagon causes weight loss by reducing food intake and increasing energy expenditure. To further understand the cellular mechanisms by which glucagon and related ligands activate the glucagon receptor (GCGR), we investigated the interaction of the GCGR with receptor activity modifying protein (RAMP)2, a member of the family of receptor activity modifying proteins. We used a combination of competition binding experiments, cell surface enzyme-linked immunosorbent assay, functional assays assessing the Gαs and Gαq pathways and β-arrestin recruitment, and small interfering RNA knockdown to examine the effect of RAMP2 on the GCGR. Ligands tested were glucagon; glucagonlike peptide-1 (GLP-1); oxyntomodulin; and analog G(X), a GLP-1/glucagon coagonist developed in-house. Confocal microscopy was used to assess whether RAMP2 affects the subcellular distribution of GCGR. Here we demonstrate that coexpression of RAMP2 and the GCGR results in reduced cell surface expression of the GCGR. This was confirmed by confocal microscopy, which demonstrated that RAMP2 colocalizes with the GCGR and causes significant GCGR cellular redistribution. Furthermore, the presence of RAMP2 influences signaling through the Gαs and Gαq pathways, as well as recruitment of β-arrestin. This work suggests that RAMP2 may modify the agonist activity and trafficking of the GCGR, with potential relevance to production of new peptide analogs with selective agonist activities.

Evidence accumulation detected in BOLD signal using slow perceptual decision making.

PubMed

Krueger, Paul M; van Vugt, Marieke K; Simen, Patrick; Nystrom, Leigh; Holmes, Philip; Cohen, Jonathan D

2017-04-01

We assessed whether evidence accumulation could be observed in the BOLD signal during perceptual decision making. This presents a challenge since the hemodynamic response is slow, while perceptual decisions are typically fast. Guided by theoretical predictions of the drift diffusion model, we slowed down decisions by penalizing participants for incorrect responses. Second, we distinguished BOLD activity related to stimulus detection (modeled using a boxcar) from activity related to integration (modeled using a ramp) by minimizing the collinearity of GLM regressors. This was achieved by dissecting a boxcar into its two most orthogonal components: an "up-ramp" and a "down-ramp." Third, we used a control condition in which stimuli and responses were similar to the experimental condition, but that did not engage evidence accumulation of the stimuli. The results revealed an absence of areas in parietal cortex that have been proposed to drive perceptual decision making but have recently come into question; and newly identified regions that are candidates for involvement in evidence accumulation. Previous fMRI studies have either used fast perceptual decision making, which precludes the measurement of evidence accumulation, or slowed down responses by gradually revealing stimuli. The latter approach confounds perceptual detection with evidence accumulation because accumulation is constrained by perceptual input. We slowed down the decision making process itself while leaving perceptual information intact. This provided a more sensitive and selective observation of brain regions associated with the evidence accumulation processes underlying perceptual decision making than previous methods. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous multielement atomic absorption spectrometry with graphite furnace atomization

NASA Astrophysics Data System (ADS)

Harnly, James M.; Miller-Ihli, Nancy J.; O'Haver, Thomas C.

The extended analytical range capability of a simultaneous multielement atomic absorption continuum source spectrometer (SIMAAC) was tested for furnace atomization with respect to the signal measurement mode (peak height and area), the atomization mode (from the wall or from a platform), and the temperature program mode (stepped or ramped atomization). These parameters were evaluated with respect to the shapes of the analytical curves, the detection limits, carry-over contamination and accuracy. Peak area measurements gave more linear calibration curves. Methods for slowing the atomization step heating rate, the use of a ramped temperature program or a platform, produced similar calibration curves and longer linear ranges than atomization with a stepped temperature program. Peak height detection limits were best using stepped atomization from the wall. Peak area detection limits for all atomization modes were similar. Carry-over contamination was worse for peak area than peak height, worse for ramped atomization than stepped atomization, and worse for atomization from a platform than from the wall. Accurate determinations (100 ± 12% for Ca, Cu, Fe, Mn, and Zn in National Bureau of Standards' Standard Reference Materials Bovine Liver 1577 and Rice Flour 1568 were obtained using peak area measurements with ramped atomization from the wall and stepped atomization from a platform. Only stepped atomization from a platform gave accurate recoveries for K. Accurate recoveries, 100 ± 10%, with precisions ranging from 1 to 36 % (standard deviation), were obtained for the determination of Al, Co, Cr, Fe, Mn, Mo, Ni. Pb, V and Zn in Acidified Waters (NBS SRM 1643 and 1643a) using stepped atomization from a platform.

A kinetic analysis of manual wheelchair propulsion during start-up on select indoor and outdoor surfaces.

PubMed

Koontz, Alicia M; Cooper, Rory A; Boninger, Michael L; Yang, Yusheng; Impink, Bradley G; van der Woude, Lucas H V

2005-01-01

The objective of this study was to conduct a kinetic analysis of manual wheelchair propulsion during start-up on select indoor and outdoor surfaces. Eleven manual wheelchairs were fitted with a SMART(Wheel) and their users were asked to push on a course consisting of high- and low-pile carpet, indoor tile, interlocking concrete pavers, smooth level concrete, grass, hardwood flooring, and a sidewalk with a 5-degree grade. Peak resultant force, wheel torque, mechanical effective force, and maximum resultant force rate of rise were analyzed during start-up for each surface and normalized relative to their steady-state values on the smooth level concrete. Additional variables included peak velocity, distance traveled, and number of strokes in the first 5 s of the trial. We compared biomechanical data between surfaces using repeated-measures mixed models and paired comparisons with a Bonferroni adjustment. Applied resultant force (p = 0.0154), wheel torque (p < 0.0001), and mechanical effective force (p = 0.0047) were significantly different between surfaces. The kinetic values for grass, interlocking pavers, and ramp ascent were typically higher compared with tile, wood, smooth level concrete, and high- and low-pile carpet. Users were found to travel shorter distances up the ramp and across grass (p < 0.0025) and had a higher stroke count on the ramp (p = 0.0124). While peak velocity was not statistically different, average velocity was slower for the ramp and grass, which indicates greater wheelchair/user deceleration between strokes. The differences noted between surfaces highlight the importance of evaluating wheelchair propulsion ability over a range of surfaces.

Centrifugal Adsorption Cartridge System

NASA Technical Reports Server (NTRS)

Gonda, Steve R.; Tsao, Yow-Min D.; Lee, Wenshan

2004-01-01

The centrifugal adsorption cartridge system (CACS) is an apparatus that recovers one or more bioproduct(s) from a dilute aqueous solution or suspension flowing from a bioreactor. The CACS can be used both on Earth in unit gravity and in space in low gravity. The CACS can be connected downstream from the bioreactor; alternatively, it can be connected into a flow loop that includes the bioreactor so that the liquid can be recycled. A centrifugal adsorption cartridge in the CACS (see figure) includes two concentric cylinders with a spiral ramp between them. The volume between the inner and outer cylinders, and between the turns of the spiral ramp is packed with an adsorbent material. The inner cylinder is a sieve tube covered with a gas-permeable, hydrophobic membrane. During operation, the liquid effluent from the bioreactor is introduced at one end of the spiral ramp, which then constrains the liquid to flow along the spiral path through the adsorbent material. The spiral ramp also makes the flow more nearly uniform than it would otherwise be, and it minimizes any channeling other than that of the spiral flow itself. The adsorbent material is formulated to selectively capture the bioproduct(s) of interest. The bioproduct(s) can then be stored in bound form in the cartridge or else eluted from the cartridge. The centrifugal effect of the spiral flow is utilized to remove gas bubbles from the liquid. The centrifugal effect forces the bubbles radially inward, toward and through the membrane of the inner cylinder. The gas-permeable, hydrophobic membrane allows the bubbles to enter the inner cylinder while keeping the liquid out. The bubbles that thus enter the cylinder are vented to the atmosphere. The spacing between the ramps determines rate of flow along the spiral, and thereby affects the air-bubble-removal efficiency. The spacing between the ramps also determines the length of the fluid path through the cartridge adsorbent, and thus affects the bioproduct-capture efficiency of the cartridge. Depending on the application, several cartridges could be connected in a serial or parallel flow arrangement. A parallel arrangement can be used to increase product-capturing and flow capacities while maintaining a low pressure drop. A serial arrangement can be used to obtain high product-capturing capacity; alternatively, series-connected cartridges can be packed with different adsorbents to capture different bioproducts simultaneously.

Twin Cities ramp meter evaluation : evaluation plan

DOT National Transportation Integrated Search

2000-09-25

The Minnesota Department of Transportation (Mn/DOT) uses ramp meters to manage freeway access on approximately 210 miles of freeways in the Twin Cities metropolitan area. Mn/DOT first tested ramp meters in 1969 as a method to optimize freeway safety ...

16. Built c. 1936, this ramp from the first to ...

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

16. Built c. 1936, this ramp from the first to the second floor along the northwestern side of Pier G (shown at the first floor) was called 'ramp C.' - Lehigh Valley Railroad, Pier G, Jersey City, Hudson County, NJ

Visual Multipoles And The Assessment Of Visual Sensitivity To Displayed Images

NASA Astrophysics Data System (ADS)

Klein, Stanley A.

1989-08-01

The contrast sensitivity function (CSF) is widely used to specify the sensitivity of the visual system. Each point of the CSF specifies the amount of contrast needed to detect a sinusoidal grating of a given spatial frequency. This paper describes a set of five mathematically related visual patterns, called "multipoles," that should replace the CSF for measuring visual performance. The five patterns (ramp, edge, line, dipole and quadrupole) are localized in space rather than being spread out as sinusoidal gratings. The multipole sensitivity of the visual system provides an alternative characterization that complements the CSF in addition to offering several advantages. This paper provides an overview of the properties and uses of the multipole stimuli. This paper is largely a summary of several unpublished manuscripts with excerpts from them. Derivations and full references are omitted here. Please write me if you would like the full manuscripts.

Examining Relay Ramp Evolution Through Paleo-shoreline Deformation Analysis, Warner Valley Fault, Oregon

NASA Astrophysics Data System (ADS)

Young, C. S.; Dawers, N. H.

2017-12-01

Fault growth is often accomplished by linking a series of en echelon faults through relay ramps. A relay ramp is the area between two overlapping fault segments that tilts and deforms as the faults accrue displacement. The structural evolution of breached normal fault relay ramps remains poorly understood because of the difficulty in defining how slip is partitioned between the most basinward fault (known as the outboard fault), the overlapping fault (inboard fault), and any ramp-breaching linking faults. Along the Warner Valley fault in south-central Oregon, two relay ramps displaying different fault linkage geometries are lined with a series of paleo-lacustrine shorelines that record a Pleistocene paleolake regression. The inner edges of these shorelines act as paleo-horizontal datums that have been deformed by fault activity, and are used to measure relative slip variations across the relay ramp bounding faults. By measuring the elevation changes using a 10m digital elevation model (DEM) of shoreline inner edges, we estimate the amount of slip partitioned between the inboard, outboard and ramp-breaching linking faults. In order to attribute shoreline deformation to fault activity we identify shoreline elevation anomalies, where deformation exceeds a ± 3.34 m window, which encompass our conservative estimates of natural variability in the shoreline geomorphology and the error associated with the data collection. Fault activity along the main length of the fault for each ramp-breaching style is concentrated near the intersection of the linking fault and the outboard portion of the main fault segment. However, fault activity along the outboard fault tip varies according to breaching style. At a footwall breach the entire outboard fault tip appears relatively inactive. At a mid-ramp breach the outboard fault tip remains relatively active because of the proximity of the linking fault to this fault tip.

23 CFR 1340.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-04-01

... OBSERVATIONAL SURVEYS OF SEAT BELT USE General § 1340.3 Definitions. As used in this part— Access ramp means the... general public are not allowed to drive motor vehicles. Nonresponse rate means, for any survey variable... location where survey data are collected. Passenger motor vehicle means a motor vehicle with a gross...

23 CFR 1340.3 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-04-01

... OBSERVATIONAL SURVEYS OF SEAT BELT USE General § 1340.3 Definitions. As used in this part— Access ramp means the... general public are not allowed to drive motor vehicles. Nonresponse rate means, for any survey variable... location where survey data are collected. Passenger motor vehicle means a motor vehicle with a gross...

23 CFR 1340.3 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-04-01

... OBSERVATIONAL SURVEYS OF SEAT BELT USE General § 1340.3 Definitions. As used in this part— Access ramp means the... general public are not allowed to drive motor vehicles. Nonresponse rate means, for any survey variable... location where survey data are collected. Passenger motor vehicle means a motor vehicle with a gross...

Management of Teenage Pregnancies in Three Different Health Care Settings.

ERIC Educational Resources Information Center

Tatelbaum, Robert

1978-01-01

This paper reports a retrospective study undertaken to determine if differences existed in obstetric outcome, contraceptive usage, and repeat pregnancy rates of teenage patients cared for in three different health care settings: the Rochester Adolescent Maternity Project (RAMP), a traditional obstetric clinic, and a neighborhood health center.…

Training Is in SCC's Genes

ERIC Educational Resources Information Center

Weinstein, Margery

2011-01-01

For SCC Soft Computer, a clinical information management systems provider, learning and development long has played an essential role in maintaining a high-growth global company. In 2010, the organization proved through ramped-up offerings, improved training success rates, and continual programming evolution that training is still a top priority.…

A 12-bit high-speed column-parallel two-step single-slope analog-to-digital converter (ADC) for CMOS image sensors.

PubMed

Lyu, Tao; Yao, Suying; Nie, Kaiming; Xu, Jiangtao

2014-11-17

A 12-bit high-speed column-parallel two-step single-slope (SS) analog-to-digital converter (ADC) for CMOS image sensors is proposed. The proposed ADC employs a single ramp voltage and multiple reference voltages, and the conversion is divided into coarse phase and fine phase to improve the conversion rate. An error calibration scheme is proposed to correct errors caused by offsets among the reference voltages. The digital-to-analog converter (DAC) used for the ramp generator is based on the split-capacitor array with an attenuation capacitor. Analysis of the DAC's linearity performance versus capacitor mismatch and parasitic capacitance is presented. A prototype 1024 × 32 Time Delay Integration (TDI) CMOS image sensor with the proposed ADC architecture has been fabricated in a standard 0.18 μm CMOS process. The proposed ADC has average power consumption of 128 μW and a conventional rate 6 times higher than the conventional SS ADC. A high-quality image, captured at the line rate of 15.5 k lines/s, shows that the proposed ADC is suitable for high-speed CMOS image sensors.

The ability of laying pullets to negotiate two ramp designs as measured by bird preference and behaviour

PubMed Central

Weeks, Claire A.; Norman, Kate I.; Nicol, Christine J.

2017-01-01

Background Laying hens are often kept in barn or free-range systems where they must negotiate level changes in the house to access resources. However, collisions and resultant keel fractures are commonplace. Producers sometimes add ramps to make raised areas more accessible but designs vary and very little research has investigated bird preference or behaviour when using different ramp designs, or the effect of ramp design on falls and collisions. Methods Two ramp designs were studied in an experimental setting—a ramp made of plastic poultry slats (grid ramp, GR) and a ramp made of wooden rungs (ladder ramp, LR). Sixty-four young female hens were trained to move to a food reward and this was used to test their behavioural responses when first negotiating the two different ramps during individual tests. Both upward and downward transitions were studied. Ramp preference was also tested using a room that replicated a commercial single-tier system with both types of ramp available. Birds were placed in this room in groups of 16 for three days and their use of the ramps studied. Results A greater percentage of birds successfully completed (reached the reward bowl) on the GR than the LR during both upward (58% vs 37%) and downward (83% vs 73%) transitions, and a smaller percentage of birds made zero attempts to use the GR than the LR (upwards: 13% vs 56%, downwards: 8% vs 26%). When making a downward transition, more hesitation behaviours were seen (head orientations, stepping on the spot, moving away) for the LR. However, more head orientations were seen for the GR during the upward transition. Birds were more likely to abort attempts (an attempt began when a bird placed both feet on the ramp) to move up the GR than the LR. Birds took longer to negotiate the LR than the GR in both directions, and more pauses were seen during a successful upward transition on the LR. Birds were more likely to move down the GR by walking/running whereas birds tended to jump over the entire LR. More collisions with the food reward bowl were seen for the LR. In the group tests, birds preferred to use the GR, with more transitions seen at all timepoints. However, in these tests, birds preferred to rest on the LR with greater numbers of birds counted on this type of ramp during scan sampling at all timepoints. Discussion Behavioural results suggest that the GR was easier for the birds to use than the LR, particularly on the downward transition. The GR was also less likely to result in collisions. However, the upward transition may be more difficult on the GR for some birds, potentially because of the inability to pause on a level surface during the transition. The results suggest that the GR was preferred by pullets for moving between a raised area and the ground but the LR was preferred for resting. PMID:29177116

Guidelines for Evaluation of Ramp Signaling Deployments in a Real-Time Operations Environment

DOT National Transportation Integrated Search

2017-12-01

State agencies have developed warrants and guidelines for the identification of on-ramps for metering. However, these warrants only consider recurrent traffic conditions in the vicinity of each on-ramp without considering the need to meter multiple r...

Ramp metering : a review of the literature.

DOT National Transportation Integrated Search

1998-01-01

Ramp metering is an effective, viable, and practical strategy used to manage freeway traffic. It is a proven freeway management technique as various forms of ramp control have been in place since the 1960s in the Chicago, Detroit, and Los Angeles are...

Aerial view looking northwest showing location of seaplane ramps 2,3, ...

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

Aerial view looking northwest showing location of seaplane ramps 2,3, and 4. Ramps lead from buildings 1 and 2, bayside left center, into San Diego Bay. - Naval Air Station North Island, North Island, San Diego, San Diego County, CA

Measuring the effectiveness of ramp metering strategies on I-12 : [tech summary].

DOT National Transportation Integrated Search

2013-10-01

In recent years, more emphasis has been placed on Active Traffi c Management (ATM) strategies such as speed harmonization, managed lanes, and : ramp metering. Ramp metering is one of the successful active traffi c control strategies, controlling the ...

Cortical pitch response components show differential sensitivity to native and nonnative pitch contours

PubMed Central

Krishnan, Ananthanarayan; Gandour, Jackson T.; Suresh, Chandan H.

2015-01-01

The aim of this study is to evaluate how nonspeech pitch contours of varying shape influence latency and amplitude of cortical pitch-specific response (CPR) components differentially as a function of language experience. Stimuli included time-varying, high rising Mandarin Tone 2 (T2) and linear rising ramp (Linear), and steady-state (Flat). Both the latency and magnitude of CPR components were differentially modulated by (i) the overall trajectory of pitch contours (time-varying vs. steady-state), (ii) their pitch acceleration rates (changing vs. constant), and (iii) their linguistic status (lexical vs. non-lexical). T2 elicited larger amplitude than Linear in both language groups, but size of the effect was larger in Chinese than English. The magnitude of CPR components elicited by T2 were larger for Chinese than English at the right temporal electrode site. Using the CPR, we provide evidence in support of experience-dependent modulation of dynamic pitch contours at an early stage of sensory processing. PMID:25306506

Aeroelastic Response and Protection of Space Shuttle External Tank Cable Trays

NASA Technical Reports Server (NTRS)

Edwards, John W.; Keller, Donald F.; Schuster, David M.; Piatak, David J.; Rausch, Russ D.; Bartels, Robert E.; Ivanco, Thomas G.; Cole, Stanley R.; Spain, Charles V.

2005-01-01

Sections of the Space Shuttle External Tank Liquid Oxygen (LO2) and Liquid Hydrogen (LH2) cable trays are shielded from potentially damaging airloads with foam Protuberance Aerodynamic Load (PAL) Ramps. Flight standard design LO2 and LH2 cable tray sections were tested with and without PAL Ramp models in the United States Air Force Arnold Engineering Development Center s (AEDC) 16T transonic wind tunnel to obtain experimental data on the aeroelastic stability and response characteristics of the trays and as part of the larger effort to determine whether the PAL ramps can be safely modified or removed. Computational Fluid Dynamic simulations of the full-stack shuttle launch configuration were used to investigate the flow characeristics around and under the cable trays without the protective PAL ramps and to define maximum crossflow Mach numbers and dynamic pressures experienced during launch. These crossflow conditions were used to establish wind tunnel test conditions which also included conservative margins. For all of the conditions and configurations tested, no aeroelastic instabilities or unacceptable dynamic response levels were encountered and no visible structural damage was experienced by any of the tested cable tray sections. Based upon this aeroelastic characterization test, three potentially acceptable alternatives are available for the LO2 cable tray PAL Ramps: Mini-Ramps, Tray Fences, or No Ramps. All configurations were tested to maximum conditions, except the LH2 trays at -15 deg. crossflow angle. This exception is the only caveat preventing the proposal of acceptable alternative configurations for the LH2 trays as well. Structural assessment of all tray loads and tray response measurements from launches following the Shuttle Return To Flight with the existing PAL Ramps will determine the acceptability of these PAL Ramp alternatives.

Measuring the effectiveness of ramp metering strategies on I-12.

DOT National Transportation Integrated Search

2013-10-01

Ramp metering is one of the successful traffic control strategies in the area of active traffic and demand management. This study evaluates the : effectiveness of a fixed time ramp metering control on the day to day operation of traffic over two segm...

Application of multi-objective nonlinear optimization technique for coordinated ramp-metering

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

Haj Salem, Habib; Farhi, Nadir; Lebacque, Jean Patrick, E-mail: abib.haj-salem@ifsttar.fr, E-mail: nadir.frahi@ifsttar.fr, E-mail: jean-patrick.lebacque@ifsttar.fr

2015-03-10

This paper aims at developing a multi-objective nonlinear optimization algorithm applied to coordinated motorway ramp metering. The multi-objective function includes two components: traffic and safety. Off-line simulation studies were performed on A4 France Motorway including 4 on-ramps.

Modelling decremental ramps using 2- and 3-parameter "critical power" models.

PubMed

Morton, R Hugh; Billat, Veronique

2013-01-01

The "Critical Power" (CP) model of human bioenergetics provides a valuable way to identify both limits of tolerance to exercise and mechanisms that underpin that tolerance. It applies principally to cycling-based exercise, but with suitable adjustments for analogous units it can be applied to other exercise modalities; in particular to incremental ramp exercise. It has not yet been applied to decremental ramps which put heavy early demand on the anaerobic energy supply system. This paper details cycling-based bioenergetics of decremental ramps using 2- and 3-parameter CP models. It derives equations that, for an individual of known CP model parameters, define those combinations of starting intensity and decremental gradient which will or will not lead to exhaustion before ramping to zero; and equations that predict time to exhaustion on those decremental ramps that will. These are further detailed with suitably chosen numerical and graphical illustrations. These equations can be used for parameter estimation from collected data, or to make predictions when parameters are known.

Turbulence evolution and transport behavior during current ramp-up in ITER-like plasmas on DIII-D

DOE PAGES

McKee, George R.; Austin, Max E.; Boedo, Jose A.; ...

2017-07-12

Low-wavenumber density fluctuations exhibit unique characteristics during the current ramp-up phase of ITER-like discharges that can partially explain the challenges of correctly modeling transport behavior and predicting global plasma parameters during this period. A strong interaction takes place between the evolving transport, safety factor (q) and kinetic profiles as well as the appearance and evolution of low-order rational surfaces. Density fluctuations from 0.75 < ρ < 0.9 are transiently reduced to exceptionally low levels during early times and from 0.8 < ρ < 0.9 at late times in the ramp-up in a manner that is different from behavior observed duringmore » steady-state plasma conditions with similar values of q 95. Turbulence is suppressed as low-order-rational q-surfaces enter the plasma; the local electron temperature likewise exhibits transient increases during these periods of reduced fluctuations indicating changes in transport that impact temperature and consequently the evolution of current density and plasma inductance. These observations can explain discrepancies between CORSICA modelling and the higher electron temperature found previously over the outer half radius. Comparison of turbulence properties with time-varying linear growth rates with GYRO and GENE demonstrate qualitative consistency with measured fluctuation levels, but calculations don’t exhibit reduced growth rates near low-order rational surfaces, which is inconsistent with experimental observations. Here, this indicates a mechanism that can contribute to reconciling observed turbulence behavior with transport models, allowing for the development of more accurate predictive tools.« less

Turbulence evolution and transport behavior during current ramp-up in ITER-like plasmas on DIII-D

NASA Astrophysics Data System (ADS)

McKee, G. R.; Austin, M.; Boedo, J.; Bravenec, R.; Holland, C.; Jackson, G.; Luce, T. C.; Rhodes, T. L.; Rudakov, D.; Wang, G.; Yan, Z.; Zeng, L.; Zhao, Y.

2017-08-01

Low-wavenumber density fluctuations exhibit unique characteristics during the current ramp-up phase of ITER-like discharges that can partially explain the challenges of correctly modeling transport behavior and predicting global plasma parameters during this period. A strong interaction takes place between the evolving transport, safety factor (q) and kinetic profiles as well as the appearance and evolution of low-order rational surfaces. Density fluctuations from 0.75  <  ρ  <  0.9 are transiently reduced to exceptionally low levels during early times and from 0.8  <  ρ  <  0.9 at late times in the ramp-up in a manner that is different from behavior observed during steady-state plasma conditions with similar values of q 95. Turbulence is suppressed as low-order-rational q-surfaces enter the plasma; the local electron temperature likewise exhibits transient increases during these periods of reduced fluctuations indicating changes in transport that impact temperature and consequently the evolution of current density and plasma inductance. These observations can explain discrepancies between CORSICA modelling and the higher electron temperature found previously over the outer half radius. Comparison of turbulence properties with time-varying linear growth rates with GYRO and GENE demonstrate qualitative consistency with measured fluctuation levels, but calculations don’t exhibit reduced growth rates near low-order rational surfaces, which is inconsistent with experimental observations. This indicates a mechanism that can contribute to reconciling observed turbulence behavior with transport models, allowing for the development of more accurate predictive tools.

Dips, ramps, and rolls- Evidence for paleotopographic and syn-depositional fault control on the Western Kentucky No. 4 coal bed, tradewater formation (Bolsovian) Illinois Basin

USGS Publications Warehouse

Greb, S.F.; Eble, C.F.; Williams, D.A.; Nelson, W.J.

2001-01-01

The Western Kentucky No. 4 coal is a high-volatile B to high-volatile C bituminous coal that has been heavily mined along the southern margin of the Western Kentucky Coal Field. The seam has a reputation for rolling floor elevation. Elongate trends of floor depressions are referred to as "dips" and "rolls" by miners. Some are relatively narrow and straight to slightly curvilinear in plan view, with generally symmetric to slightly asymmetric cross-sections. Others are broader and asymmetric in section, with sharp dips on one limb and gradual, ramp-like dips on the other. Some limbs change laterally from gradual dip, to sharp dip, to offset of the coal. Lateral changes in the rate of floor elevation dip are often associated with changes in coal thickness, and in underground mines, changes in floor elevation are sometimes associated with roof falls and haulage problems. In order to test if coal thickness changes within floor depressions were associated with changes in palynology, petrography and coal quality, the coal was sampled at a surface mine across a broad. ramp-like depression that showed down-dip coal thickening. Increment samples of coal from a thick (150 cm), down-ramp and thinner (127 cm), up-ramp position at one surface mine correlate well between sample sites (a distance of 60 m) except for a single increment. The anomalous increment (31 cm) in the lower-middle part of the thick coal bed contained 20% more Lycospora orbicula spores. The rolling floor elevations noted in the study mines are inferred to have been formed as a result of pre-peat paleotopographic depressions, syn-depositional faulting, fault-controlled pre-peat paleotopography, and from compaction beneath post-depositional channels and slumps. Although the association of thick coal with linear trends and inferred faults has been used in other basins to infer syn-depositional faulting, changes in palynology within increment samples of the seam along a structural ramp in this study provide subtle evidence of faulting within a specific increment of the coal itself. The sudden increase in L. orbicula (produced by Paralycopodites) in a single increment of a down-ramp sample of the Western Kentucky No. 4 coal records the reestablishment of a rheotrophic mire following a sudden change in edaphic conditions. Paralycopodites was a colonizing lycopod, which in this case became locally abundant after the peat was well established along a fault with obvious growth during peat accumulation. Because many coal-mire plants were susceptible to sudden edaphic changes as might accompany faulting or flooding, changes in palynology would be expected in coals affected by syn-depositional faulting. ?? 2001 Elsevier Science B.V. All rights reserved.

Siskiyou summit negative grade arrester bed for runaway trucks : final report.

DOT National Transportation Integrated Search

1986-01-01

Most escape ramps are designed to use gravity as the primary deceleration mechanism. These ramps provide an exit from the roadway to an adjacent hillside, ascending at grades of up to 40%. Loose gravel is often used on these ramps which, while aiding...

Structure function analysis of two-scale Scalar Ramps. Part I: Theory and Modeling

USDA-ARS?s Scientific Manuscript database

Structure functions are used to study the dissipation and inertial range scales of turbulent energy, to parameterize remote turbulence measurements, and to characterize ramp features in the turbulent field. The ramp features are associated with turbulent coherent structures, which dominate energy an...

Exploration of the SHRP2 naturalistic driving study data to identify factors related to the selection of freeway ramp design speed.

DOT National Transportation Integrated Search

2017-03-01

This research explored the second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) database for the potential to identify freeway entrance and exit ramps and teen drivers behavior while traveling those ramps. This is in ...

Using archived ITS data to measure the operational benefits of a system-wide adaptive ramp metering system.

DOT National Transportation Integrated Search

2008-12-01

A System-Wide Adaptive Ramp Metering (SWARM) system has been implemented in the Portland, Oregon metropolitan area, replacing the previous pre-timed ramp-metering system that had been in operation since 1981. SWARM has been deployed on six major corr...

Portable and Lightweight Ramp Structure

DTIC Science & Technology

2001-04-09

long side of which is in abutting relationship with the 12 short side of the end of the ramp. Fastener receivers are equi- 13 spaced in duplicate...The modular sections are conveniently prefabricated 18 1 and provided in kit form to the number of sections corresponding 2 to the desired ramp

Structure function analysis of two-scale Scalar Ramps. Part II: Coherent structure scaling and surface renewal applications

USDA-ARS?s Scientific Manuscript database

Structure functions are used to study the dissipation and inertial range scales of turbulent energy, to parameterize remote turbulence measurements, and to characterize ramp features in the turbulent field. The ramp features are associated with turbulent coherent structures, which dominate energy a...

Pathfinder Rear Ramp

NASA Image and Video Library

1997-07-06

NASA's Mars Pathfinder's rear rover ramp can be seen successfully unfurled in this image, taken at the end of Sol 2 by the Imager for Mars Pathfinder (IMP). This ramp was later used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. Areas of a lander petal and deflated airbag are visible at left. The image helped Pathfinder scientists determine that the rear ramp was the one to use for rover deployment. At upper right is the rock dubbed "Barnacle Bill," which Sojourner will later study. http://photojournal.jpl.nasa.gov/catalog/PIA00627

Wind Power Ramping Product for Increasing Power System Flexibility

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

Cui, Mingjian; Zhang, Jie; Wu, Hongyu

With increasing penetrations of wind power, system operators are concerned about a potential lack of system flexibility and ramping capacity in real-time dispatch stages. In this paper, a modified dispatch formulation is proposed considering the wind power ramping product (WPRP). A swinging door algorithm (SDA) and dynamic programming are combined and used to detect WPRPs in the next scheduling periods. The detected WPRPs are included in the unit commitment (UC) formulation considering ramping capacity limits, active power limits, and flexible ramping requirements. The modified formulation is solved by mixed integer linear programming. Numerical simulations on a modified PJM 5-bus Systemmore » show the effectiveness of the model considering WPRP, which not only reduces the production cost but also does not affect the generation schedules of thermal units.« less

A polyhedral study of production ramping

DOE PAGES

Damci-Kurt, Pelin; Kucukyavuz, Simge; Rajan, Deepak; ...

2015-06-12

Here, we give strong formulations of ramping constraints—used to model the maximum change in production level for a generator or machine from one time period to the next—and production limits. For the two-period case, we give a complete description of the convex hull of the feasible solutions. The two-period inequalities can be readily used to strengthen ramping formulations without the need for separation. For the general case, we define exponential classes of multi-period variable upper bound and multi-period ramping inequalities, and give conditions under which these inequalities define facets of ramping polyhedra. Finally, we present exact polynomial separation algorithms formore » the inequalities and report computational experiments on using them in a branch-and-cut algorithm to solve unit commitment problems in power generation.« less

Evolution of plasma wakes in density up- and down-ramps

NASA Astrophysics Data System (ADS)

Zhang, C. J.; Joshi, C.; Xu, X. L.; Mori, W. B.; Li, F.; Wan, Y.; Hua, J. F.; Pai, C. H.; Wang, J.; Lu, W.

2018-02-01

The time evolution of plasma wakes in density up- and down-ramps is examined through theory and particle-in-cell simulations. Motivated by observation of the reversal of a linear plasma wake in a plasma density upramp in a recent experiment (Zhang et al 2017 Phys. Rev. Lett. 119 064801) we have examined the behaviour of wakes in plasma ramps that always accompany any plasma source used for plasma-based acceleration. In the up-ramp case it is found that, after the passage of the drive pulse, the wavnumber/wavelength of the wake starts to decrease/increase with time until it eventually tends to zero/infinity, then the wake reverses its propagation direction and the wavenunber/wavelength of the wake begins to increase/shrink. The evolutions of the wavenumber and the phase velocity of the wake as functions of time are shown to be significantly different in the up-ramp and the down-ramp cases. In the latter case the wavenumber of the wake at a particular position in the ramp increases until the wake is eventually damped. It is also shown that the waveform of the wake at a particular time after being excited can be precisely controlled by tuning the initial plasma density profile, which may enable a new type of plasma-based ultrafast optics.

TRANSP-based Trajectory Optimization of the Current Profile Evolution to Facilitate Robust Non-inductive Ramp-up in NSTX-U

NASA Astrophysics Data System (ADS)

Wehner, William; Schuster, Eugenio; Poli, Francesca

2016-10-01

Initial progress towards the design of non-inductive current ramp-up scenarios in the National Spherical Torus Experiment Upgrade (NSTX-U) has been made through the use of TRANSP predictive simulations. The strategy involves, first, ramping the plasma current with high harmonic fast waves (HHFW) to about 400 kA, and then further ramping to 900 kA with neutral beam injection (NBI). However, the early ramping of neutral beams and application of HHFW leads to an undesirably peaked current profile making the plasma unstable to ballooning modes. We present an optimization-based control approach to improve on the non-inductive ramp-up strategy. We combine the TRANSP code with an optimization algorithm based on sequential quadratic programming to search for time evolutions of the NBI powers, the HHFW powers, and the line averaged density that define an open-loop actuator strategy that maximizes the non-inductive current while satisfying constraints associated with the current profile evolution for MHD stable plasmas. This technique has the potential of playing a critical role in achieving robustly stable non-inductive ramp-up, which will ultimately be necessary to demonstrate applicability of the spherical torus concept to larger devices without sufficient room for a central coil. Supported by the US DOE under the SCGSR Program.

The in vitro inflation response of mouse sclera.

PubMed

Myers, Kristin M; Cone, Frances E; Quigley, Harry A; Gelman, Scott; Pease, Mary E; Nguyen, Thao D

2010-12-01

The purpose of this research was to develop a reliable and repeatable inflation protocol to measure the scleral inflation response of mouse eyes to elevations in intraocular pressure (IOP), comparing the inflation response exhibited by the sclera of younger and older C57BL/6 mice. Whole, enucleated eyes from younger (2 month) and older (11 month) C57BL/6 mice were mounted by the cornea on a custom fixture and inflated according to a load-unload, ramp-hold pressurization regimen via a cannula connected to a saline-filled programmable syringe pump. First, the tissue was submitted to three load-unload cycles from 6 mmHg to 15 mmHg at a rate of 0.25 mmHg/s with ten minutes of recovery between cycles. Next the tissue was submitted to a series of ramp-hold tests to measure the creep behavior at different pressure levels. For each ramp-hold test, the tissue was loaded from 6 mmHg to the set pressure at a rate of 0.25 mmHg/s and held for 30 min, and then the specimens were unloaded to 6 mmHg for 10 min. This sequence was repeated for set pressures of: 10.5, 15, 22.5, 30, 37.5, and 45 mmHg. Scleral displacement was measured using digital image correlation (DIC), and fresh scleral thickness was measured optically for each specimen after testing. For comparison, scleral thickness was measured on untested fresh tissue and epoxy-fixed tissue from age-matched animals. Comparing the apex displacement of the different aged specimens, the sclera of older animals had a statistically significant stiffer response to pressurization than the sclera of younger animals. The stiffness of the pressure-displacement response of the apex measured in the small-strain (6-15 mmHg) and the large-strain (37.5-45 mmHg) regime, respectively, were 287 ± 100 mmHg/mm and 2381 ± 191 mmHg/mm for the older tissue and 193 ± 40 mmHg/mm and 1454 ± 93 mmHg/mm for the younger tissue (Student t-test, p<0.05). The scleral thickness varied regionally, being thickest in the peripapillary region and thinnest at the equator. Fresh scleral thickness did not differ significantly by age in this group of animals. This study presents a reliable inflation test protocol to measure the mechanical properties of mouse sclera. The inflation methodology was sensitive enough to measure scleral response to changes in IOP elevations between younger and older C57BL/6 mice. Further, the specimen-specific scleral displacement profile and thickness measurements will enable future development of specimen-specific finite element models to analyze the inflation data for material properties. Copyright © 2010 Elsevier Ltd. All rights reserved.

Revisiting Frank-Starling: regulatory light chain phosphorylation alters the rate of force redevelopment (ktr ) in a length-dependent fashion.

PubMed

Toepfer, Christopher N; West, Timothy G; Ferenczi, Michael A

2016-09-15

Regulatory light chain (RLC) phosphorylation has been shown to alter the ability of muscle to produce force and power during shortening and to alter the rate of force redevelopment (ktr ) at submaximal [Ca(2+) ]. Increasing RLC phosphorylation ∼50% from the in vivo level in maximally [Ca(2+) ]-activated cardiac trabecula accelerates ktr . Decreasing RLC phosphorylation to ∼70% of the in vivo control level slows ktr and reduces force generation. ktr is dependent on sarcomere length in the physiological range 1.85-1.94 μm and RLC phosphorylation modulates this response. We demonstrate that Frank-Starling is evident at maximal [Ca(2+) ] activation and therefore does not necessarily require length-dependent change in [Ca(2+) ]-sensitivity of thin filament activation. The stretch response is modulated by changes in RLC phosphorylation, pinpointing RLC phosphorylation as a modulator of the Frank-Starling law in the heart. These data provide an explanation for slowed systolic function in the intact heart in response to RLC phosphorylation reduction. Force and power in cardiac muscle have a known dependence on phosphorylation of the myosin-associated regulatory light chain (RLC). We explore the effect of RLC phosphorylation on the ability of cardiac preparations to redevelop force (ktr ) in maximally activating [Ca(2+) ]. Activation was achieved by rapidly increasing the temperature (temperature-jump of 0.5-20ºC) of permeabilized trabeculae over a physiological range of sarcomere lengths (1.85-1.94 μm). The trabeculae were subjected to shortening ramps over a range of velocities and the extent of RLC phosphorylation was varied. The latter was achieved using an RLC-exchange technique, which avoids changes in the phosphorylation level of other proteins. The results show that increasing RLC phosphorylation by 50% accelerates ktr by ∼50%, irrespective of the sarcomere length, whereas decreasing phosphorylation by 30% slows ktr by ∼50%, relative to the ktr obtained for in vivo phosphorylation. Clearly, phosphorylation affects the magnitude of ktr following step shortening or ramp shortening. Using a two-state model, we explore the effect of RLC phosphorylation on the kinetics of force development, which proposes that phosphorylation affects the kinetics of both attachment and detachment of cross-bridges. In summary, RLC phosphorylation affects the rate and extent of force redevelopment. These findings were obtained in maximally activated muscle at saturating [Ca(2+) ] and are not explained by changes in the Ca(2+) -sensitivity of acto-myosin interactions. The length-dependence of the rate of force redevelopment, together with the modulation by the state of RLC phosphorylation, suggests that these effects play a role in the Frank-Starling law of the heart. © 2016 Wellcome Trust The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Monitoring wildlife-vehicle collisions : analysis and cost-benefit of escape ramps for deer and elk on U.S. highway 550.

DOT National Transportation Integrated Search

2015-05-01

Wildlife fencing along highways can lower wildlife-vehicle collision rates by excluding animals from the road right-of-way. Still, animals can : breach fencing and end up trapped within the fencing along the highway right-of-way, exposing wildlife an...

75 FR 67083 - Magnuson-Stevens Act Provisions; General Provisions for Domestic Fisheries; Application for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-01

... Research program. The primary objective of this study is to assess the effects of different stressors on... Reflex Action Mortality Predictors (RAMP) under different stressors to assess the discard mortality rates... research landings from the VTRs in their ACE accounting, in addition to the vessel's dealer-recorded...

Verification of experimental dynamic strength methods with atomistic ramp-release simulations

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

Moore, Alexander P.; Brown, Justin L.; Lim, Hojun

Material strength and moduli can be determined from dynamic high-pressure ramp-release experiments using an indirect method of Lagrangian wave profile analysis of surface velocities. This method, termed self-consistent Lagrangian analysis (SCLA), has been difficult to calibrate and corroborate with other experimental methods. Using nonequilibrium molecular dynamics, we validate the SCLA technique by demonstrating that it accurately predicts the same bulk modulus, shear modulus, and strength as those calculated from the full stress tensor data, especially where strain rate induced relaxation effects and wave attenuation are small. We show here that introducing a hold in the loading profile at peak pressuremore » gives improved accuracy in the shear moduli and relaxation-adjusted strength by reducing the effect of wave attenuation. When rate-dependent effects coupled with wave attenuation are large, we find that Lagrangian analysis overpredicts the maximum unload wavespeed, leading to increased error in the measured dynamic shear modulus. Furthermore, these simulations provide insight into the definition of dynamic strength, as well as a plausible explanation for experimental disagreement in reported dynamic strength values.« less

Verification of experimental dynamic strength methods with atomistic ramp-release simulations

NASA Astrophysics Data System (ADS)

Moore, Alexander P.; Brown, Justin L.; Lim, Hojun; Lane, J. Matthew D.

2018-05-01

Material strength and moduli can be determined from dynamic high-pressure ramp-release experiments using an indirect method of Lagrangian wave profile analysis of surface velocities. This method, termed self-consistent Lagrangian analysis (SCLA), has been difficult to calibrate and corroborate with other experimental methods. Using nonequilibrium molecular dynamics, we validate the SCLA technique by demonstrating that it accurately predicts the same bulk modulus, shear modulus, and strength as those calculated from the full stress tensor data, especially where strain rate induced relaxation effects and wave attenuation are small. We show here that introducing a hold in the loading profile at peak pressure gives improved accuracy in the shear moduli and relaxation-adjusted strength by reducing the effect of wave attenuation. When rate-dependent effects coupled with wave attenuation are large, we find that Lagrangian analysis overpredicts the maximum unload wavespeed, leading to increased error in the measured dynamic shear modulus. These simulations provide insight into the definition of dynamic strength, as well as a plausible explanation for experimental disagreement in reported dynamic strength values.

Research on three-phase traffic flow modeling based on interaction range

NASA Astrophysics Data System (ADS)

Zeng, Jun-Wei; Yang, Xu-Gang; Qian, Yong-Sheng; Wei, Xu-Ting

2017-12-01

On the basis of the multiple velocity difference effect (MVDE) model and under short-range interaction, a new three-phase traffic flow model (S-MVDE) is proposed through careful consideration of the influence of the relationship between the speeds of the two adjacent cars on the running state of the rear car. The random slowing rule in the MVDE model is modified in order to emphasize the influence of vehicle interaction between two vehicles on the probability of vehicles’ deceleration. A single-lane model which without bottleneck structure under periodic boundary conditions is simulated, and it is proved that the traffic flow simulated by S-MVDE model will generate the synchronous flow of three-phase traffic theory. Under the open boundary, the model is expanded by adding an on-ramp, the congestion pattern caused by the bottleneck is simulated at different main road flow rates and on-ramp flow rates, which is compared with the traffic congestion pattern observed by Kerner et al. and it is found that the results are consistent with the congestion characteristics in the three-phase traffic flow theory.

Verification of experimental dynamic strength methods with atomistic ramp-release simulations

DOE PAGES

Moore, Alexander P.; Brown, Justin L.; Lim, Hojun; ...

2018-05-04

Material strength and moduli can be determined from dynamic high-pressure ramp-release experiments using an indirect method of Lagrangian wave profile analysis of surface velocities. This method, termed self-consistent Lagrangian analysis (SCLA), has been difficult to calibrate and corroborate with other experimental methods. Using nonequilibrium molecular dynamics, we validate the SCLA technique by demonstrating that it accurately predicts the same bulk modulus, shear modulus, and strength as those calculated from the full stress tensor data, especially where strain rate induced relaxation effects and wave attenuation are small. We show here that introducing a hold in the loading profile at peak pressuremore » gives improved accuracy in the shear moduli and relaxation-adjusted strength by reducing the effect of wave attenuation. When rate-dependent effects coupled with wave attenuation are large, we find that Lagrangian analysis overpredicts the maximum unload wavespeed, leading to increased error in the measured dynamic shear modulus. Furthermore, these simulations provide insight into the definition of dynamic strength, as well as a plausible explanation for experimental disagreement in reported dynamic strength values.« less

The plastic response of Tantalum in Quasi-Isentropic Compression Ramp and Release

NASA Astrophysics Data System (ADS)

Moore, Alexander; Brown, Justin; Lim, Hojun; Lane, J. Matthew D.

2017-06-01

The mechanical response of various forms of tantalum under extreme pressures and strain rates is studied using dynamic quasi-isentropic compression loading conditions in atomistic simulations. Ramp compression in bcc metals under these conditions tend to show a significant strengthening effect with increasing pressure; however, due to limitations of experimental methods in such regimes, the underlying physics for this phenomenon is not well understood. Molecular dynamics simulations provide important information about the plasticity mechanisms and can be used to investigate this strengthening. MD simulations are performed on nanocrystalline Ta and single crystal defective Ta with dislocations and point defects to uncover how the material responds and the underlying plasticity mechanisms. The different systems of solid Ta are seen to plastically deform through different mechanisms. Fundamental understanding of tantalum plasticity in these high pressure and strain rate regimes is needed to model and fully understand experimental results. Sandia National Labs is a multi program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Bacterial expression and purification of a heterodimeric adrenomedullin receptor extracellular domain complex using DsbC-assisted disulfide shuffling.

PubMed

Hill, Heather E; Pioszak, Augen A

2013-03-01

Adrenomedullin (AM) is a peptide hormone that is a potent vasodilator and is essential for vascular development. The AM receptor is a heterodimeric cell surface receptor composed of the calcitonin receptor-like receptor (CLR), a class B G protein-coupled receptor, in association with either of two receptor activity modifying protein (RAMP) coreceptors, RAMP2 or -3. The extracellular domains (ECDs) of CLR and the RAMPs form the primary AM binding site. Here, we present novel methodology for expression and purification of a heterodimeric AM receptor ECD complex as an MBP-CLR ECD fusion protein in association with the RAMP2 ECD. Co-expression of the RAMP2 ECD with the disulfide bond isomerase DsbC in the oxidizing cytoplasm of E. coli trxB gor enabled proper disulfide formation in vivo. The isolated RAMP2 ECD was purified to homogeneity. Co-expression of a soluble MBP-CLR ECD fusion protein with DsbC in E. coli trxB gor yielded a heterogeneous mixture of species with misfolded ECD. Incubation of affinity-purified MBP-CLR ECD in vitro with purified RAMP2 ECD, DsbC, and glutathione redox buffer promoted proper folding of the CLR ECD and formation of a stable MBP-CLR ECD:RAMP2 ECD complex that was purified by size-exclusion chromatography and which exhibited specific AM binding. Approximately 40mg of highly purified complex was obtained starting with 6L bacterial cultures for each protein. The methodology reported here will facilitate structure/function studies of the AM receptor. Copyright © 2012 Elsevier Inc. All rights reserved.

Therapeutic effect of polysaccharide fraction of Atractylodis macrocephalae Koidz. in bovine subclinical mastitis.

PubMed

Xu, Wei; Guan, Ran; Lu, Yisong; Su, Xiaoyan; Xu, Ye; Du, Aifang; Hu, Songhua

2015-07-25

Mastitis is considered the most significant and persistent disease in dairy cows, bringing about large economic losses. Subclinical mastitis brings about major cost implications, for it is difficult to detect due to absence of any visible indications and can persist in the mammary tissue throughout lactation. Immunomodulators have been widely used to reduce intramammary infections by modulating bovine mammary gland. Atractylodis macrocephalae Koidz. polysaccharides (RAMP), extracted from herbal medicine, has been used widely especially for its immunomodulatory function for many years. The objective of this study was to estimate an oil emulsified Atractylodis macrocephalae Koidz. polysaccharides (RAMP-O) as a potential therapeutic agent to treat subclinical mastitis by subcutaneous injection of RAMP-O in the area of supramammary lymph node in lactating cows via analysis of SCC, IMIs and NAGase. Injection of RAMP-O in the area of supramammary lymph node significantly reduced milk SCC and NAGase activity compared with control. The quarters with bacterial infection were also progressively reduced in RAMP-O treated cows and only 9 quarters were found to have bacterial infection, while no obvious change was found in the control group. Subcutaneous injection of RAMP-O in the area of supramammary lymph node had therapeutic value in the treatment of bovine subclinical mastitis by reducing SCC, NAGase and IMIs in milk. Considering both the therapeutic effect and the cost of RAMP-O, 32 mg per dose was found most suitable to reduce milk SCC and NAGase. Therefore, RAMP-O deserves further study for its use in treatment of bovine mastitis.

The immune adjuvant response of polysaccharides from Atractylodis macrocephalae Koidz in chickens vaccinated against Newcastle disease (ND).

PubMed

Zhao, Xiaona; Sun, Wenjing; Zhang, Shijie; Meng, Guangju; Qi, Chunhua; Fan, Wentao; Wang, Yuge; Liu, Jianzhu

2016-05-05

Build on our previous research, polysaccharides from the rhizome of Atractylodis macrocephalae Koidz (RAMPS), RAMPStp and RAMPS60c were prepared and the structural characterization and immune response of ND vaccine in chicken were investigated. Immune organ index, Lymphocyte proliferation, antibody titers, cell cycle distribution, and percentages of CD4(+) and CD8(+) cells were determined. GPC analysis showed that the Mn of RAMPS with two peaks were 1.29×10(5) and 1.74×10(3), respectively. GC-MS analysis revealed that RAMPS was composed of glucose, mannose, arabinose, galactose, xylose, d-Ribose and rhamnose, with mass percentages of 66.39%, 21.24%, 5.64%, 2.65%, 2.30%, 1.15% and 0.64%, respectively. NMR spectroscopic analysis demonstrated that a preliminary structure of RAMPS was proposed as 1,3-linked β-d-Galp and 1,6-linked β-d-Galpresidues. In vivo test showed that RAMPStp and RAMPS60c could promote peripheral lymphocytes proliferation and entering into S and G2/M phases, enhance serum HI antibody titer and effectively improve the percentages of CD4(+) and CD8(+) T cells in chickens vaccinated with ND vaccine at most time points. The actions of RAMPStp and RAMPS60c were stronger than that of Lev, and RAMPStp presented the best efficacy. These results indicated that RAMPStp and RAMPS60c characterize of the immune-enhancing activity and RAMPStp possessed the strongest activity. It would be anticipated as a component of new-type immunopotentiator. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cracking of coated materials under transient thermal stresses

NASA Technical Reports Server (NTRS)

Rizk, A. A.; Erdogan, Fazil

1988-01-01

The crack problem for a relatively thin layer bonded to a very thick substrate under thermal shock conditions is considered. The effect of surface cooling rate is studied by assuming the temperature boundary condition to be a ramp function. Among the crack geometries considered are the edge crack in the coating layer, the broken layer, the edge crack going through the interface, the undercoat crack in the substrate and the embedded crack crossing the interface. The primary calculated quantity is the stress intensity factor at various singular points and the main variables are the relative sizes and locations of cracks, the time, and the duration of the cooling ramp. The problem is solved and rather extensive results are given for two material pairs, namely a stainless steel layer welded on a ferritic medium and a ceramic coating on a steel substrate.

Cracking of coated materials under transient thermal stresses

NASA Technical Reports Server (NTRS)

Rizk, A. A.; Erdogan, F.

1989-01-01

The crack problem for a relatively thin layer bonded to a very thick substrate under thermal shock conditions is considered. The effect of surface cooling rate is studied by assuming the temperature boundary condition to be a ramp function. Among the crack geometries considered are the edge crack in the coating layer, the broken layer, the edge crack going through the interface, the undercoat crack in the substrate and the embedded crack crossing the interface. The primary calculated quantity is the stress intensity factor at various singular points and the main variables are the relative sizes and locations of cracks, the time, and the duration of the cooling ramp. The problem is solved and rather extensive results are given for two material pairs, namely a stainless steel layer welded on a ferritic medium and a ceramic coating on a steel substrate.

1 μs broadband frequency sweeping reflectometry for plasma density and fluctuation profile measurements

NASA Astrophysics Data System (ADS)

Clairet, F.; Bottereau, C.; Medvedeva, A.; Molina, D.; Conway, G. D.; Silva, A.; Stroth, U.; ASDEX Upgrade Team; Tore Supra Team; Eurofusion Mst1 Team

2017-11-01

Frequency swept reflectometry has reached the symbolic value of 1 μs sweeping time; this performance has been made possible, thanks to an improved control of the ramp voltage driving the frequency source. In parallel, the memory depth of the acquisition system has been upgraded and can provide up to 200 000 signals during a plasma discharge. Additional improvements regarding the trigger delay determination of the acquisition and the voltage ramp linearity required by this ultra-fast technique have been set. While this diagnostic is traditionally dedicated to the plasma electron density profile measurement, such a fast sweeping rate can provide the study of fast plasma events and turbulence with unprecedented time and radial resolution from the edge to the core. Experimental results obtained on ASDEX Upgrade plasmas are presented to demonstrate the performances of the diagnostic.

Integrated modeling of plasma ramp-up in DIII-D ITER-like and high bootstrap current scenario discharges

NASA Astrophysics Data System (ADS)

Wu, M. Q.; Pan, C. K.; Chan, V. S.; Li, G. Q.; Garofalo, A. M.; Jian, X.; Liu, L.; Ren, Q. L.; Chen, J. L.; Gao, X.; Gong, X. Z.; Ding, S. Y.; Qian, J. P.; Cfetr Physics Team

2018-04-01

Time-dependent integrated modeling of DIII-D ITER-like and high bootstrap current plasma ramp-up discharges has been performed with the equilibrium code EFIT, and the transport codes TGYRO and ONETWO. Electron and ion temperature profiles are simulated by TGYRO with the TGLF (SAT0 or VX model) turbulent and NEO neoclassical transport models. The VX model is a new empirical extension of the TGLF turbulent model [Jian et al., Nucl. Fusion 58, 016011 (2018)], which captures the physics of multi-scale interaction between low-k and high-k turbulence from nonlinear gyro-kinetic simulation. This model is demonstrated to accurately model low Ip discharges from the EAST tokamak. Time evolution of the plasma current density profile is simulated by ONETWO with the experimental current ramp-up rate. The general trend of the predicted evolution of the current density profile is consistent with that obtained from the equilibrium reconstruction with Motional Stark effect constraints. The predicted evolution of βN , li , and βP also agrees well with the experiments. For the ITER-like cases, the predicted electron and ion temperature profiles using TGLF_Sat0 agree closely with the experimental measured profiles, and are demonstrably better than other proposed transport models. For the high bootstrap current case, the predicted electron and ion temperature profiles perform better in the VX model. It is found that the SAT0 model works well at high IP (>0.76 MA) while the VX model covers a wider range of plasma current ( IP > 0.6 MA). The results reported in this paper suggest that the developed integrated modeling could be a candidate for ITER and CFETR ramp-up engineering design modeling.

Orofacial and thumb-index finger ramp-and-hold isometric force dynamics in young neurotypical adults.

PubMed

Barlow, Steven M; Hozan, Mohsen; Lee, Jaehoon; Greenwood, Jake; Custead, Rebecca; Wardyn, Brianna; Tippin, Kaytlin

2018-04-27

The relation among several parameters of the ramp-and-hold isometric force contraction (peak force and dF/dt max during the initial phase of force recruitment, and the proportion of hold-phase at target) was quantified for the right and left thumb-index finger pinch, and lower lip midline compression in 40 neurotypical right-handed young adults (20 female/20 males) using wireless force sensors and data acquisition technology developed in our laboratory. In this visuomotor control task, participants produced ramp-and-hold isometric forces as 'rapidly and accurately' as possible to end-point target levels at 0.25, 0.5, 1 and 2 Newtons presented to a computer monitor in a randomized block design. Significant relations were found between the parameters of the ramp-and-hold lip force task and target force level, including the peak rate of force change (dF/dt max ), peak force, and the criterion percentage of force within ±5% of target during the contraction hold phase. A significant performance advantage was found among these force variables for the thumb-index finger over the lower lip. The maximum voluntary compression force (MVCF) task revealed highly significant differences in force output between the thumb-index fingers and lower lip (∼4.47-4.70 times greater for the digits versus lower lip), a significant advantage of the right thumb-index finger over the non-dominant left thumb-index finger (12% and 25% right hand advantage for males and females, respectively), and a significant sex difference (∼1.65-1.73 times greater among males). Copyright © 2018 Elsevier Ltd. All rights reserved.

Numerical investigation of improving the performance of a single expansion ramp nozzle at off-design conditions by secondary injection

NASA Astrophysics Data System (ADS)

Lv, Zheng; Xu, Jinglei; Mo, Jianwei

2017-04-01

The performance of a single expansion ramp nozzle (SERN) is poor due to over-expansion at off-design conditions. The present study focuses on improving the SERN performance by secondary injection on the cowl and is carried out by using the k - ε RNG turbulence model. The incidence shock wave resulting from the secondary injection impinges on the expansion ramp, resulting in separation and the increase of the pressure distribution along the ramp. The performance of the SERN can be improved significantly, and the augmentation of the thrust coefficient, lift and pitch moment can be as high as 3.16%, 29.43% and 41.67%, respectively, when the nozzle pressure ratio (NPR) is 10. The location of the injection has a considerable effect on the lift and pitching moment, and the direction of the pitch moment can be changed from nose-up to nose-down when the injection is on the tail of the cowl. The effect of the injection on the axial thrust coefficient is much more apparent, if the operation NPR is far from the design point, and however, the results for the lift and pitching moment are opposite. The increases of injection total pressure and injection width have positive impacts on the SERN performance. And if the parameter φ maintains constant, the axial thrust coefficient would increase when the injection total pressure decreases, so low energy flow can also be used as the secondary injection without decreasing the lift and pitching moment. The mass flow rate of the injection can be decreased by applying the higher total temperature flow without reducing the performance of the SERN.

Effects of Jet Swirl on Mixing of a Light Gas Jet in a Supersonic Airstream

NASA Technical Reports Server (NTRS)

Doerner, Steven E.; Cutler, Andrew D.

1999-01-01

A non reacting experiment was performed to investigate the effects of jet swirl on mixing of a light gas jet in a supersonic airstream. The experiment consisted of two parts. The first part was an investigation of the effects of jet swirl and skew on the mixing and penetration of a 25 deg. supersonic jet injected from a flat surface (flush wall injection) into a supersonic ducted airflow. Specifically, the objective was to determine whether the jet would mix more rapidly if the jet were swirling, and whether swirl, with and without skew, causes the injectant-air plume to have a net circulation (i.e., a single or dominant vortex). The second part was a preliminary study of the mixing of swirling jets injected from the base of a skewed ramp. The hypothesis was that favorable interactions between vorticity generated by the swirling jet and vortices generated by the ramp could produce mixing enhancements. Both parts of the experiment were conducted at equal injectant mass flow rate and total pressure. The results for the flush wall injection cases indicate that, except relatively close to the injection point, swirl, with or without skew, does not enhance the mixing of the jet, and can in fact reduce penetration. In addition, a plume with significant net circulation is not generated, as had previously been believed. The results for the ramp cases indicated no improvements in mixing in comparison with the baseline (swept ramp injector) case. However, it was not possible to determine the vorticity mechanisms underlying the poor performance, since no measurements of vorticity were made. Thus, since many geometric parameters were chosen arbitrarily, the results are inconclusive for this class of injector.

Analysis and Characterization of Organic Carbon in Early Holocene Wetland Paleosols using Ramped Pyrolysis 14C and Biomarkers

NASA Astrophysics Data System (ADS)

Vetter, L.; Schreiner, K. M.; Fernandez, A.; Rosenheim, B. E.; Tornqvist, T. E.

2014-12-01

Radiocarbon analyses are a key tool for quantifying the dynamics of carbon cycling and storage in both modern soils and Quaternary paleosols. Frequently, bulk 14C dates of paleosol organic carbon provide ages older than the time of soil burial, and 14C dates of geochemical fractions such as alkali and acid extracts (operationally defined as humic acids) can provide anomalously old ages when compared to coeval plant macrofossil dates. Ramped pyrolysis radiocarbon analysis of sedimentary organic material has been employed as a tool for investigating 14C age spectra in sediments with multiple organic carbon sources. Here we combine ramped pyrolysis 14C analysis and biomarker analysis (lignin-phenols and other cupric oxide products) to provide information on the source and diagenetic state of the paleosol organic carbon. We apply these techniques to immature early Holocene brackish wetland entisols from three sediment cores in southeastern Louisiana, along with overlying basal peats. Surprisingly, we find narrow 14C age spectra across all thermal aliquots from both paleosols and peats. The weighted bulk 14C ages from paleosols and overlying peats are within analytical error, and are comparable to independently analyzed 14C AMS dates from charcoal fragments and other plant macrofossils from each peat bed. Our results suggest high turnover rates of carbon in soils relative to input of exogenous carbon sources. These data raise broader questions about processes within the active soil and during pedogenesis and burial of paleosols that can effectively homogenize radiocarbon content in soils across the thermochemical spectrum. The concurrence of paleosol and peat 14C ages also suggests that, in the absence of peats with identifiable plant macrofossils, ramped pyrolysis 14C analyses of paleosols may be used to provide ages for sea-level indicators.

14. VIEW OF THE MODERN CONCRETE RAMP THAT CONNECTED THE ...

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

14. VIEW OF THE MODERN CONCRETE RAMP THAT CONNECTED THE UPPER AND LOWER MINE ROADS. TRUCKS USED THIS RAMP AND THE ROADS TO HAUL SLAG TO THE MINE DUMP. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

36 CFR 1192.81 - Lighting.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Vehicles and Systems § 1192.81 Lighting. (a) Any stepwell or doorway with a lift, ramp or bridge plate... measured on the step tread or lift platform. (b) Other stepwells, and doorways with lifts, ramps or bridge... lift or ramp, when deployed at the vehicle floor level. (c) The doorways of vehicles not operating at...

36 CFR 1192.81 - Lighting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Vehicles and Systems § 1192.81 Lighting. (a) Any stepwell or doorway with a lift, ramp or bridge plate... measured on the step tread or lift platform. (b) Other stepwells, and doorways with lifts, ramps or bridge... lift or ramp, when deployed at the vehicle floor level. (c) The doorways of vehicles not operating at...

Third Expert Consultation on RAMP (RAMP III) (Helsinki, Finland, September 13, 15 and 20, 1986). Final Report.

ERIC Educational Resources Information Center

United Nations Educational, Scientific and Cultural Organization, Paris (France). General Information Programme.

Organized for the United Nations Educational, Scientific, and Cultural Organization (Unesco) by contract with the International Council on Archives (ICA), this meeting concerning the Records and Archives Management Programme (RAMP) was attended by 14 experts invited from Unesco member countries. Following a brief introduction, summaries are…

Structural basis for receptor activity-modifying protein-dependent selective peptide recognition by a G protein-coupled receptor

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

Booe, Jason M.; Walker, Christopher S.; Barwell, James

Association of receptor activity-modifying proteins (RAMP1-3) with the G protein-coupled receptor (GPCR) calcitonin receptor-like receptor (CLR) enables selective recognition of the peptides calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) that have diverse functions in the cardiovascular and lymphatic systems. How peptides selectively bind GPCR:RAMP complexes is unknown. We report crystal structures of CGRP analog-bound CLR:RAMP1 and AM-bound CLR:RAMP2 extracellular domain heterodimers at 2.5 and 1.8 Å resolutions, respectively. The peptides similarly occupy a shared binding site on CLR with conformations characterized by a β-turn structure near their C termini rather than the α-helical structure common to peptides that bind relatedmore » GPCRs. The RAMPs augment the binding site with distinct contacts to the variable C-terminal peptide residues and elicit subtly different CLR conformations. Lastly, the structures and accompanying pharmacology data reveal how a class of accessory membrane proteins modulate ligand binding of a GPCR and may inform drug development targeting CLR:RAMP complexes.« less

Structural basis for receptor activity-modifying protein-dependent selective peptide recognition by a G protein-coupled receptor

DOE PAGES

Booe, Jason M.; Walker, Christopher S.; Barwell, James; ...

2015-05-14

Association of receptor activity-modifying proteins (RAMP1-3) with the G protein-coupled receptor (GPCR) calcitonin receptor-like receptor (CLR) enables selective recognition of the peptides calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) that have diverse functions in the cardiovascular and lymphatic systems. How peptides selectively bind GPCR:RAMP complexes is unknown. We report crystal structures of CGRP analog-bound CLR:RAMP1 and AM-bound CLR:RAMP2 extracellular domain heterodimers at 2.5 and 1.8 Å resolutions, respectively. The peptides similarly occupy a shared binding site on CLR with conformations characterized by a β-turn structure near their C termini rather than the α-helical structure common to peptides that bind relatedmore » GPCRs. The RAMPs augment the binding site with distinct contacts to the variable C-terminal peptide residues and elicit subtly different CLR conformations. Lastly, the structures and accompanying pharmacology data reveal how a class of accessory membrane proteins modulate ligand binding of a GPCR and may inform drug development targeting CLR:RAMP complexes.« less

Evaluation and enhancement of Texas ramp metering strategies, compliance, and alternative enforcement techniques: Go with the flow Houston. Public outreach plan (revised); Interim research report, September 1995--October 1996

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

Lancaster, S.; Fette, B.; Busler, L.

This report describes the public outreach plan on the implementation of ramp meters along the Katy Freeway in Houston, Generally, ramp metering is neither beloved nor understood by the public. To gain public awareness, acceptance, compliance and continued support, ramp metering operations should be reinforced by a strong, ongoing public information and outreach campaign that communicates the need for and benefits of the program. Because the term `ramp metering` exhibits restrictions on the public, the phrase `Flow Signals` was developed to better describe the benefits of ramp metering; enhanced flow of traffic, fewer bottlenecks, and fewer trip delays. The logo,more » `Go with the Flow Houston,` and a graphic identity were developed to help communicate the theme throughout the various media where both the primary and secondary messages are intended to reach 15 different audiences. These media will include: a PSA, both static and changeable message signs, a brochure, Internet web site information, letters to specific audience and media relations efforts.« less

A robotic observatory in the city

NASA Astrophysics Data System (ADS)

Ruch, Gerald T.; Johnston, Martin E.

2012-05-01

The University of St. Thomas (UST) Observatory is an educational facility integrated into UST's undergraduate curriculum as well as the curriculum of several local schools. Three characteristics combine to make the observatory unique. First, the telescope is tied directly to the support structure of a four-story parking ramp instead of an isolated pier. Second, the facility can be operated remotely over an Internet connection and is capable of performing observations without a human operator. Third, the facility is located on campus in the heart of a metropolitan area where light pollution is severe. Our tests indicate that, despite the lack of an isolated pier, vibrations from the ramp do not degrade the image quality at the telescope. The remote capability facilitates long and frequent observing sessions and allows others to use the facility without traveling to UST. Even with the high background due to city lights, the sensitivity and photometric accuracy of the system are sufficient to fulfill our pedagogical goals and to perform a variety of scientific investigations. In this paper, we outline our educational mission, provide a detailed description of the observatory, and discuss its performance characteristics.

Computational study of single-expansion-ramp nozzles with external burning

NASA Astrophysics Data System (ADS)

Yungster, Shaye; Trefny, Charles J.

1992-04-01

A computational investigation of the effects of external burning on the performance of single expansion ramp nozzles (SERN) operating at transonic speeds is presented. The study focuses on the effects of external heat addition and introduces a simplified injection and mixing model based on a control volume analysis. This simplified model permits parametric and scaling studies that would have been impossible to conduct with a detailed CFD analysis. The CFD model is validated by comparing the computed pressure distribution and thrust forces, for several nozzle configurations, with experimental data. Specific impulse calculations are also presented which indicate that external burning performance can be superior to other methods of thrust augmentation at transonic speeds. The effects of injection fuel pressure and nozzle pressure ratio on the performance of SERN nozzles with external burning are described. The results show trends similar to those reported in the experimental study, and provide additional information that complements the experimental data, improving our understanding of external burning flowfields. A study of the effect of scale is also presented. The results indicate that combustion kinetics do not make the flowfield sensitive to scale.

Computational study of single-expansion-ramp nozzles with external burning

NASA Technical Reports Server (NTRS)

Yungster, Shaye; Trefny, Charles J.

1992-01-01

A computational investigation of the effects of external burning on the performance of single expansion ramp nozzles (SERN) operating at transonic speeds is presented. The study focuses on the effects of external heat addition and introduces a simplified injection and mixing model based on a control volume analysis. This simplified model permits parametric and scaling studies that would have been impossible to conduct with a detailed CFD analysis. The CFD model is validated by comparing the computed pressure distribution and thrust forces, for several nozzle configurations, with experimental data. Specific impulse calculations are also presented which indicate that external burning performance can be superior to other methods of thrust augmentation at transonic speeds. The effects of injection fuel pressure and nozzle pressure ratio on the performance of SERN nozzles with external burning are described. The results show trends similar to those reported in the experimental study, and provide additional information that complements the experimental data, improving our understanding of external burning flowfields. A study of the effect of scale is also presented. The results indicate that combustion kinetics do not make the flowfield sensitive to scale.

Color Mosaic of Rover & Terrain

NASA Image and Video Library

1997-07-05

NASA's Sojourner rover and undeployed ramps onboard the Mars Pathfinder spacecraft can be seen in this image, by the Imager for Mars Pathfinder (IMP) on July 4 (Sol 1). This image has been corrected for the curvature created by parallax. The microrover Sojourner is latched to the petal, and has not yet been deployed. The ramps are a pair of deployable metal reels which will provide a track for the rover as it slowly rolls off the lander, over the spacecraft's deflated airbags, and onto the surface of Mars. Pathfinder scientists will use this image to determine whether it is safe to deploy the ramps. One or both of the ramps will be unfurled, and then scientists will decide whether the rover will use either the forward or backward ramp for its descent. http://photojournal.jpl.nasa.gov/catalog/PIA00621

High temperature seal for large structural movements

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M. (Inventor); Dunlap, Jr., Patrick H. (Inventor)

2004-01-01

A high temperature sealing system is operative to seal an interface between adjacent hot structures and to minimize parasitic flow between such structures that move relative to one another in-plane or out-of-plane. The sealing system may be used to seal thrust-directing ramp structures of a reusable launch vehicle and includes a channel and a plurality of movable segmented sealing elements. Adjacent ramp structures include edge walls which extend within the channel. The sealing elements are positioned along the sides of the channel and are biased to engage with the inner surfaces of the ramp structures. The segmented sealing elements are movable to correspond to the contour of the thrust-directing ramp structures. The sealing system is operative to prevent high temperature thrust gases that flow along the ramp structures from infiltrating into the interior of the vehicle.

Fully non-inductive second harmonic electron cyclotron plasma ramp-up in the QUEST spherical tokamak

NASA Astrophysics Data System (ADS)

Idei, H.; Kariya, T.; Imai, T.; Mishra, K.; Onchi, T.; Watanabe, O.; Zushi, H.; Hanada, K.; Qian, J.; Ejiri, A.; Alam, M. M.; Nakamura, K.; Fujisawa, A.; Nagashima, Y.; Hasegawa, M.; Matsuoka, K.; Fukuyama, A.; Kubo, S.; Shimozuma, T.; Yoshikawa, M.; Sakamoto, M.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Ide, S.; Maekawa, T.; Takase, Y.; Toi, K.

2017-12-01

Fully non-inductive second (2nd) harmonic electron cyclotron (EC) plasma current ramp-up was demonstrated with a newlly developed 28 GHz system in the QUEST spherical tokamak. A high plasma current of 54 kA was non-inductively ramped up and sustained stably for 0.9 s with a 270 kW 28 GHz wave. A higher plasma current of 66 kA was also non-inductively achieved with a slow ramp-up of the vertical field. We have achieved a significantly higher plasma current than those achieved previously with the 2nd harmonic EC waves. This fully non-inductive 2nd harmonic EC plasma ramp-up method might be useful for future burning plasma devices and fusion reactors, in particular for operations at half magnetic field with the same EC heating equipment.

Testing of Two-Speed Transmission Configurations for Use in Rotorcraft

NASA Technical Reports Server (NTRS)

Lewicki, David G.; Stevens, Mark A.

2015-01-01

Large civil tiltrotors have been identified to replace regional airliners over medium ranges to alleviate next-generation air traffic. Variable rotor speed for these vehicles is required for efficient high-speed operation. Two-speed drive system research has been performed to support these advanced rotorcraft applications. Experimental tests were performed on two promising two-speed transmission configurations. The offset compound gear (OCG) transmission and the dual star/idler (DSI) planetary transmission were tested in the NASA Glenn Research Center variable-speed transmission test facility. Both configurations were inline devices with concentric input and output shafts and designed to provide 1:1 and 2:1 output speed reduction ratios. Both were designed for 200 hp and 15,000 rpm input speed and had a dry shift clutch configuration. Shift tests were performed on the transmissions at input speeds of 5,000, 8,000, 10,000, 12,500, and 15,000 rpm. Both the OCG and DSI configurations successfully perform speed shifts at full rated 15,000 rpm input speed. The transient shifting behavior of the OCG and DSI configurations were very similar. The shift clutch had more of an effect on shifting dynamics than the reduction gearing configuration itself since the same shift clutch was used in both configurations. For both OCG and DSI configurations, low-to-high speed shifts were limited in applied torque levels in order to prevent overloads on the transmission due to transient torque spikes. It is believed that the relative lack of appreciable slippage of the dry shifting clutch at operating conditions and pressure profiles tested was a major cause of the transient torque spikes. For the low-to-high speed shifts, the output speed ramp-up time slightly decreased and the peak out torque slightly increased as the clutch pressure ramp-down rate increased. This was caused by slightly less clutch slippage as the clutch pressure ramp-down rate increased.

Evaluation of the quality of care of a multi-disciplinary Risk Factor Assessment and Management Programme for Hypertension (RAMP-HT).

PubMed

Yu, Esther Yee Tak; Wan, Eric Yuk Fai; Chan, Karina Hiu Yen; Wong, Carlos King Ho; Kwok, Ruby Lai Ping; Fong, Daniel Yee Tak; Lam, Cindy Lo Kuen

2015-06-19

There is some evidence to support a risk-stratified, multi-disciplinary approach to manage patients with hypertension in primary care. The aim of this study is to evaluate the quality of care (QOC) of a multi-disciplinary Risk Assessment and Management Programme for Hypertension (RAMP-HT) for hypertensive patients in busy government-funded primary care clinics in Hong Kong. The objectives are to develop an evidence-based, structured and comprehensive evaluation framework on quality of care, to enhance the QOC of the RAMP-HT through an audit spiral of two evaluation cycles and to determine the effectiveness of the programme in reducing cardiovascular disease (CVD) risk. A longitudinal study is conducted using the Action Learning and Audit Spiral methodologies to measure whether pre-set target standards of care intended by the RAMP-HT are achieved. A structured evaluation framework on the quality of structure, process and outcomes of care has been developed based on the programme objectives and literature review in collaboration with the programme workgroup and health service providers. Each participating clinic is invited to complete a structure of care evaluation questionnaire in each evaluation cycle. The data of all patients who have enrolled into the RAMP-HT in the pre-defined evaluation periods are used for the evaluation of the process and outcomes of care in each evaluation cycle. For evaluation of the effectiveness of RAMP-HT, the primary outcomes including blood pressure (both systolic and diastolic), low-density lipoprotein cholesterol and estimated 10-year CVD risk of RAMP-HT participants are compared to those of hypertensive patients in usual care without RAMP-HT. The QOC and effectiveness of the RAMP-HT in improving clinical and patient-reported outcomes for patients with hypertension in normal primary care will be determined. Possible areas for quality enhancement and standards of good practice will be established to inform service planning and policy decision making.

Rowing Crew Coordination Dynamics at Increasing Stroke Rates

PubMed Central

2015-01-01

In rowing, perfect synchronisation is important for optimal performance of a crew. Remarkably, a recent study on ergometers demonstrated that antiphase crew coordination might be mechanically more efficient by reducing the power lost to within-cycle velocity fluctuations of the boat. However, coupled oscillator dynamics predict the stability of the coordination to decrease with increasing stroke rate, which in case of antiphase may eventually yield breakdowns to in-phase. Therefore, this study examined the effects of increasing stroke rate on in- and antiphase crew coordination in rowing dyads. Eleven experienced dyads rowed on two mechanically coupled ergometers on slides, which allowed the ergometer system to move back and forth as one ‘boat’. The dyads performed a ramp trial in both in- and antiphase pattern, in which stroke rates gradually increased from 30 strokes per minute (spm) to as fast as possible in steps of 2 spm. Kinematics of rowers, handles and ergometers were captured. Two dyads showed a breakdown of antiphase into in-phase coordination at the first stroke rate of the ramp trial. The other nine dyads reached between 34–42 spm in antiphase but achieved higher rates in in-phase. As expected, the coordinative accuracy in antiphase was worse than in in-phase crew coordination, while, somewhat surprisingly, the coordinative variability did not differ between the patterns. Whereas crew coordination did not substantially deteriorate with increasing stroke rate, stroke rate did affect the velocity fluctuations of the ergometers: fluctuations were clearly larger in the in-phase pattern than in the antiphase pattern, and this difference significantly increased with stroke rate. Together, these results suggest that although antiphase rowing is less stable (i.e., less resistant to perturbation), potential on-water benefits of antiphase over in-phase rowing may actually increase with stroke rate. PMID:26185987

STEREO Observations of Waves in the Ramp Regions of Interplanetary Shocks

NASA Astrophysics Data System (ADS)

Cohen, Z.; Breneman, A. W.; Cattell, C. A.; Davis, L.; Grul, P.; Kersten, K.; Wilson, L. B., III

2017-12-01

Determining the role of plasma waves in providing energy dissipation at shock waves is of long-standing interest. Interplanetary (IP) shocks serve as a large database of low Mach number shocks. We examine electric field waveforms captured by the Time Domain Sampler (TDS) on the STEREO spacecraft during the ramps of IP shocks, with emphasis on captures lasting 2.1 seconds. Previous work has used captures of shorter duration (66 and 131 ms on STEREO, and 17 ms on WIND), which allowed for observation of waves with maximum (minimum) frequencies of 125 kHz (15 Hz), 62.5 kHz (8 Hz), and 60 kHz (59 Hz), respectively. The maximum frequencies are comparable to 2-8 times the plasma frequency in the solar wind, enabling observation of Langmuir waves, ion acoustic, and some whistler-mode waves. The 2 second captures resolve lower frequencies ( few Hz), which allows us to analyze packet structure of the whistler-mode waves and some ion acoustic waves. The longer capture time also improves the resolvability of simultaneous wave modes and of waves with frequencies on the order of 10s of Hz. Langmuir waves, however, cannot be identified at this sampling rate, since the plasma frequency is usually higher than 3.9 kHz. IP shocks are identified from multiple databases (Helsinki heliospheric shock database at http://ipshocks.fi, and the STEREO level 3 shock database at ftp://stereoftp.nascom.nasa.gov/pub/ins_data/impact/level3/). Our analysis focuses on TDS captures in shock ramp regions, with ramp durations determined from magnetic field data taken at 8 Hz. Software is used to identify multiple wave modes in any given capture and classify waves as Langmuir, ion acoustic, whistler, lower hybrid, electron cyclotron drift instability, or electrostatic solitary waves. Relevant frequencies are determined from density and magnetic field data collected in situ. Preliminary results suggest that large amplitude (≥ 5 mV/m) ion acoustic waves are most prevalent in the ramp, in agreement with Wilson, et al. Other modes are also observed. Statistical results will be presented and compared with previous studies and theoretical predictions.

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

Tucker, Eric; Boreman, Glenn, E-mail: gboreman@uncc.edu; D'Archangel, Jeffrey

Near- and far-field measurements of phase-ramped loop and patch structures are presented and compared to simulations. The far-field deflection measurements show that the phase-ramped structures can deflect a beam away from specular reflection, consistent with simulations. Scattering scanning near-field optical microscopy of the elements comprising the phase ramped structures reveals part of the underlying near-field phase contribution that dictates the far-field deflection, which correlates with the far-field phase behavior that was expected. These measurements provide insight into the resonances, coupling, and spatial phase variation among phase-ramped frequency selective surface (FSS) elements, which are important for the performance of FSS reflectarrays.

RAMP: A fault tolerant distributed microcomputer structure for aircraft navigation and control

NASA Technical Reports Server (NTRS)

Dunn, W. R.

1980-01-01

RAMP consists of distributed sets of parallel computers partioned on the basis of software and packaging constraints. To minimize hardware and software complexity, the processors operate asynchronously. It was shown that through the design of asymptotically stable control laws, data errors due to the asynchronism were minimized. It was further shown that by designing control laws with this property and making minor hardware modifications to the RAMP modules, the system became inherently tolerant to intermittent faults. A laboratory version of RAMP was constructed and is described in the paper along with the experimental results.

Early Observations with the ACS Ramp Filters

NASA Astrophysics Data System (ADS)

Tsvetanov, Z.; Hartig, G.; Bohlin, R.; Tran, H. D.; Martel, A.; Sirianni, M.; Clampin, M.

2002-05-01

The Advanced Camera for Surveys (ACS) on-board the Hubble Space Telescope (HST) is equipped with a set of ramp filters which provide imaging capability at 2% and 9% bandwidth in the range 3700-10700 Å. Each ramp filter consist of three segments where the middle segment can be used with both the Wide Field Channel (WFC) and High Resolution Channel (HRC), while the inner and outer segments can be used only with WFC. The monochromatic field of view is approximately 40'' by 80''. We will present observations of the planetary nebula (PN) NGC6543 (the Cat's Eye) taken with the ACS ramp filetrs in several key emission lines - [O II] 3727, [O III] 5007, H-alpha+[N II], and [S II] 6725. These four emission lines fall onto three separate middle ramp segments - FR388N, FR505N, and FR656N - and will allow inter-comparison between the ACS ramp filters and fixed bandpass narrow-band filters F502N and F658N for both the WFC and HRC detectors. These observations were taken as part of the HST Servicing Mission Orbital Verification program and were designed to test ramp filters performance. We will demostrate our ability to obtain monochromatic (i.e., emission line) images at arbitrary wavelength and recover the surface brightness distribution. This work was supported by a NASA contract and a NASA grant.

40 CFR 1042.505 - Testing engines using discrete-mode or ramped-modal duty cycles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Testing engines using discrete-mode or...-IGNITION ENGINES AND VESSELS Test Procedures § 1042.505 Testing engines using discrete-mode or ramped-modal... the Clean Air Act. (a) You may perform steady-state testing with either discrete-mode or ramped-modal...

40 CFR 1039.505 - How do I test engines using steady-state duty cycles, including ramped-modal testing?

Code of Federal Regulations, 2010 CFR

2010-07-01

...-state duty cycles, including ramped-modal testing? 1039.505 Section 1039.505 Protection of Environment... duty cycles, including ramped-modal testing? This section describes how to test engines under steady-state conditions. In some cases, we allow you to choose the appropriate steady-state duty cycle for an...

Downscaling Solar Power Output to 4-Seconds for Use in Integration Studies (Presentation)

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

Hummon, M.; Weekley, A.; Searight, K.

2013-10-01

High penetration renewable integration studies require solar power data with high spatial and temporal accuracy to quantify the impact of high frequency solar power ramps on the operation of the system. Our previous work concentrated on downscaling solar power from one hour to one minute by simulation. This method used clearness classifications to categorize temporal and spatial variability, and iterative methods to simulate intra-hour clearness variability. We determined that solar power ramp correlations between sites decrease with distance and the duration of the ramp, starting at around 0.6 for 30-minute ramps between sites that are less than 20 km apart.more » The sub-hour irradiance algorithm we developed has a noise floor that causes the correlations to approach ~0.005. Below one minute, the majority of the correlations of solar power ramps between sites less than 20 km apart are zero, and thus a new method to simulate intra-minute variability is needed. These intra-minute solar power ramps can be simulated using several methods, three of which we evaluate: a cubic spline fit to the one-minute solar power data; projection of the power spectral density toward the higher frequency domain; and average high frequency power spectral density from measured data. Each of these methods either under- or over-estimates the variability of intra-minute solar power ramps. We show that an optimized weighted linear sum of methods, dependent on the classification of temporal variability of the segment of one-minute solar power data, yields time series and ramp distributions similar to measured high-resolution solar irradiance data.« less

Downscaling Solar Power Output to 4-Seconds for Use in Integration Studies: Preprint

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

Hummon, M.; Weekley, A.; Searight, K.

2013-10-01

High penetration renewable integration studies require solar power data with high spatial and temporal accuracy to quantify the impact of high frequency solar power ramps on the operation of the system. Our previous work concentrated on downscaling solar power from one hour to one minute by simulation. This method used clearness classifications to categorize temporal and spatial variability, and iterative methods to simulate intra-hour clearness variability. We determined that solar power ramp correlations between sites decrease with distance and the duration of the ramp, starting at around 0.6 for 30-minute ramps between sites that are less than 20 km apart.more » The sub-hour irradiance algorithm we developed has a noise floor that causes the correlations to approach ~0.005. Below one minute, the majority of the correlations of solar power ramps between sites less than 20 km apart are zero, and thus a new method to simulate intra-minute variability is needed. These intra-minute solar power ramps can be simulated using several methods, three of which we evaluate: a cubic spline fit to the one-minute solar power data; projection of the power spectral density toward the higher frequency domain; and average high frequency power spectral density from measured data. Each of these methods either under- or over-estimates the variability of intra-minute solar power ramps. We show that an optimized weighted linear sum of methods, dependent on the classification of temporal variability of the segment of one-minute solar power data, yields time series and ramp distributions similar to measured high-resolution solar irradiance data.« less

LOCALIZATION OF CALCITONIN RECEPTOR-LIKE RECEPTOR (CLR) AND RECEPTOR ACTIVITY-MODIFYING PROTEIN 1 (RAMP1) IN HUMAN GASTROINTESTINAL TRACT

PubMed Central

Cottrell, Graeme S.; Alemi, Farzad; Kirkland, Jacob G.; Grady, Eileen F.; Corvera, Carlos U.; Bhargava, Aditi

2012-01-01

Calcitonin gene-related peptide (CGRP) exerts its diverse effects on vasodilation, nociception, secretion, and motor function through a heterodimeric receptor comprising of calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1). Despite the importance of CLR•RAMP1 in human disease, little is known about its distribution in the human gastrointestinal (GI) tract, where it participates in inflammation and pain. In this study, we determined that CLR and RAMP1 mRNAs are expressed in normal human stomach, ileum and colon by RT-PCR. We next characterized antibodies that we generated to rat CLR and RAMP1 in transfected HEK cells. Having characterized these antibodies in vitro, we then localized CLR-, RAMP1-, CGRP- and intermedin-immunoreactivity (IMD-IR) in various human GI segments. In the stomach, nerve bundles in the myenteric plexus and nerve fibers throughout the circular and longitudinal muscle had prominent CLR-IR. In the proximal colon and ileum, CLR was found in nerve varicosities of the myenteric plexus and surrounding submucosal neurons. Interestingly, CGRP expressing fibers did not co-localize, but were in close proximity to CLR. However, CLR and RAMP1, the two subunits of a functional CGRP receptor were clearly localized in myenteric plexus, where they may form functional cell-surface receptors. IMD, another member of calcitonin peptide family was also found in close proximity to CLR, and like CGRP, did not co-localize with either CLR or RAMP1 receptors. Thus, CGRP and IMD appear to be released locally, where they can mediate their effect on their receptors regulating diverse functions such as inflammation, pain and motility. PMID:22484227

On artifacts in single-molecule force spectroscopy

PubMed Central

Cossio, Pilar; Hummer, Gerhard; Szabo, Attila

2015-01-01

In typical force spectroscopy experiments, a small biomolecule is attached to a soft polymer linker that is pulled with a relatively large bead or cantilever. At constant force, the total extension stochastically changes between two (or more) values, indicating that the biomolecule undergoes transitions between two (or several) conformational states. In this paper, we consider the influence of the dynamics of the linker and mesoscopic pulling device on the force-dependent rate of the conformational transition extracted from the time dependence of the total extension, and the distribution of rupture forces in force-clamp and force-ramp experiments, respectively. For these different experiments, we derive analytic expressions for the observables that account for the mechanical response and dynamics of the pulling device and linker. Possible artifacts arise when the characteristic times of the pulling device and linker become comparable to, or slower than, the lifetimes of the metastable conformational states, and when the highly anharmonic regime of stretched linkers is probed at high forces. We also revisit the problem of relating force-clamp and force-ramp experiments, and identify a linker and loading rate-dependent correction to the rates extracted from the latter. The theory provides a framework for both the design and the quantitative analysis of force spectroscopy experiments by highlighting, and correcting for, factors that complicate their interpretation. PMID:26540730

Transient three-dimensional startup side load analysis of a regeneratively cooled nozzle

NASA Astrophysics Data System (ADS)

Wang, Ten-See

2009-07-01

The objective of this effort is to develop a computational methodology to capture the side load physics and to anchor the computed aerodynamic side loads with the available data by simulating the startup transient of a regeneratively cooled, high-aspect-ratio nozzle, hot-fired at sea level. The computational methodology is based on an unstructured-grid, pressure-based, reacting flow computational fluid dynamics and heat transfer formulation, and a transient inlet history based on an engine system simulation. Emphases were put on the effects of regenerative cooling on shock formation inside the nozzle, and ramp rate on side load reduction. The results show that three types of asymmetric shock physics incur strong side loads: the generation of combustion wave, shock transitions, and shock pulsations across the nozzle lip, albeit the combustion wave can be avoided with sparklers during hot-firing. Results from both regenerative cooled and adiabatic wall boundary conditions capture the early shock transitions with corresponding side loads matching the measured secondary side load. It is theorized that the first transition from free-shock separation to restricted-shock separation is caused by the Coanda effect. After which the regeneratively cooled wall enhances the Coanda effect such that the supersonic jet stays attached, while the hot adiabatic wall fights off the Coanda effect, and the supersonic jet becomes detached most of the time. As a result, the computed peak side load and dominant frequency due to shock pulsation across the nozzle lip associated with the regeneratively cooled wall boundary condition match those of the test, while those associated with the adiabatic wall boundary condition are much too low. Moreover, shorter ramp time results show that higher ramp rate has the potential in reducing the nozzle side loads.

Fast, precise, and widely tunable frequency control of an optical parametric oscillator referenced to a frequency comb.

PubMed

Prehn, Alexander; Glöckner, Rosa; Rempe, Gerhard; Zeppenfeld, Martin

2017-03-01

Optical frequency combs (OFCs) provide a convenient reference for the frequency stabilization of continuous-wave lasers. We demonstrate a frequency control method relying on tracking over a wide range and stabilizing the beat note between the laser and the OFC. The approach combines fast frequency ramps on a millisecond timescale in the entire mode-hop free tuning range of the laser and precise stabilization to single frequencies. We apply it to a commercially available optical parametric oscillator (OPO) and demonstrate tuning over more than 60 GHz with a ramping speed up to 3 GHz/ms. Frequency ramps spanning 15 GHz are performed in less than 10 ms, with the OPO instantly relocked to the OFC after the ramp at any desired frequency. The developed control hardware and software are able to stabilize the OPO to sub-MHz precision and to perform sequences of fast frequency ramps automatically.

Static internal performance of a single expansion ramp nozzle with multiaxis thrust vectoring capability

NASA Technical Reports Server (NTRS)

Capone, Francis J.; Schirmer, Alberto W.

1993-01-01

An investigation was conducted at static conditions in order to determine the internal performance characteristics of a multiaxis thrust vectoring single expansion ramp nozzle. Yaw vectoring was achieved by deflecting yaw flaps in the nozzle sidewall into the nozzle exhaust flow. In order to eliminate any physical interference between the variable angle yaw flap deflected into the exhaust flow and the nozzle upper ramp and lower flap which were deflected for pitch vectoring, the downstream corners of both the nozzle ramp and lower flap were cut off to allow for up to 30 deg of yaw vectoring. The effects of nozzle upper ramp and lower flap cutout, yaw flap hinge line location and hinge inclination angle, sidewall containment, geometric pitch vector angle, and geometric yaw vector angle were studied. This investigation was conducted in the static-test facility of the Langley 16-Foot Transonic Tunnel at nozzle pressure ratios up to 8.0.

Micro-Ramp Flow Control for Oblique Shock Interactions: Comparisons of Computational and Experimental Data

NASA Technical Reports Server (NTRS)

Hirt, Stefanie M.; Reich, David B.; O'Connor, Michael B.

2010-01-01

Computational fluid dynamics was used to study the effectiveness of micro-ramp vortex generators to control oblique shock boundary layer interactions. Simulations were based on experiments previously conducted in the 15 x 15 cm supersonic wind tunnel at NASA Glenn Research Center. Four micro-ramp geometries were tested at Mach 2.0 varying the height, chord length, and spanwise spacing between micro-ramps. The overall flow field was examined. Additionally, key parameters such as boundary-layer displacement thickness, momentum thickness and incompressible shape factor were also examined. The computational results predicted the effects of the micro-ramps well, including the trends for the impact that the devices had on the shock boundary layer interaction. However, computing the shock boundary layer interaction itself proved to be problematic since the calculations predicted more pronounced adverse effects on the boundary layer due to the shock than were seen in the experiment.

What Do Kinematic Models Imply About the Constitutive Properties of Rocks Deformed in Flat-Ramp-Flat Folds?

NASA Astrophysics Data System (ADS)

Cruz, L.; Nevitt, J. M.; Seixas, G.; Hilley, G. E.

2017-10-01

Kinematic theories of flat-ramp-flat folds relate fault angles to stratal dips in a way that allows prediction of structural geometries in areas of economic or scientific interest. However, these geometric descriptions imply constitutive properties of rocks that might be discordant with field and laboratory measurements. In this study, we compare deformation resulting from kinematic and mechanical models of flat-ramp-flat folds with identical geometries to determine the conditions over which kinematic models may be reasonably applied to folded rocks. Results show that most mechanical models do not conform to the geometries predicted by the kinematic models, and only low basal friction (μ ≤ 0.1) and shallow ramps (ramp angle ≤10°) produce geometries consistent with kinematic predictions. This implies that the kinematic models might be appropriate for a narrow set of geometric and basal fault friction parameters.

Expression of recombinant antibacterial lactoferricin-related peptides from Pichia pastoris expression system.

PubMed

Chen, Gen-Hung; Chen, Wei-Ming; Huang, Guo-Ting; Chen, Yu-Wen; Jiang, Shann-Tzong

2009-10-28

Four recombinant antimicrobial peptide (rAMP) cDNAs, constructed from two goat lactoferricin-related peptide cDNAs (GLFcin and GLFcin II) with/without (His)(6)-Tag, were cloned into pPICZalphaC and transformed into Pichia pastoris SMD1168H. After methanol induction, these rAMPs were expressed and secreted into broth. They were purified after CM-Sepharose (without His-tg), HisTrap (with His-tg) and Sephadex G-25 chromatographies. The yield of purified rAMP was 0.15 mg/mL of broth. These 4 rAMPs were thermal-stable and with high antibacterial activity against Escherichia coli BCRC 11549, Pseudomonas aeruginosa BCRC 12450, Bacillus cereus BCRC 10603, Staphylococcus aureus BCRC 25923, Propioni bacterium acnes BCRC 10723, and Listera monocytogenes BCRC 14845. The minimum inhibitory concentration (MIC) of rAMPs against these indicators ranged from 4.07 to 16.00 mg/mL.

[Comparison between gastric and esophageal mechano-sensitivity in patients with functional dyspepsia].

PubMed

López Gastón, A R; López De Luise, G A; Andrüsh, A

1996-01-01

Patients with non ulcer dyspepsia (NUD) and lowered mechano sensitivity thresholds in stomach may have lowered mechano sensitivity thresholds in oesophagus also. The aim was to check this hypothesis. 39 patients with NUD (11 men and 24 women, mean age 57 years, SEM 3.72, range 17-86) and 20 controls (10 men, 10 women, mean age 49.3 years, SEM 3.72, range 31-66) were studied. Organis diseases were discarded. Gastric mechano sensitivity was studied with a latex balloon of low compliance, 8 cm length, connected to a manometer. Balloon was inflated "in ramp" at 10 ml/sec, and "first sensation", discomfort", and "pain" were registered. At 900 ml inflation was stopped if pain was not evoked. Oesophageal mechano sensitivity was studied with another latex balloon of low compliance which, after inflated with 15 ml. of air, was 3.5 cm. in diameter. Esophageal balloon was inflated "in ramp" (1 ml/sec) up 15 ml. and deflated in 2 cm step from 36 to 22 cm from SDA. Inflation was stopped when symptoms (pain or discomfort were evoked. Oesophageal acid perfusion test was performed. 83.4% of controls completed up 700 ml. of gastric distension vs. 35.9% of patients with NUD (p > 0.001). No significative differences in intra-balloon pressure slope were observed between both groups. 79.2% of NUD patients had chest pain with oesophageal ballon distension = < 7 ml. vs. 5% in controls (p > 0.001). Mean volumes were 7.03 ml. (NUD) and 11.9% (controls) (p = 0.001), 63% of dyspeptic patients with lowered gastric sensitivity thresholds (< 700 ml) had oesophagic symptoms with inflation volumes = < 7 ml. There was a positive correlation in stomach and oesophageal mechano sensitivities variations (r = 0.75, +/- 0.58, p > 0.01). When analyzed with that results, oesophageal acid perfusion test showed 38.5% of "mixed sensitivities" (both mechano- and chemo-), 30.7% of "mechano sensorials" (negative acid test, positive balloon test), and 10.3% of :chemo sensorials" (positive acid test only). In 20.5% both tests were normal at the moment they were done. These results agreed with our previous experiences in oesophagus. It was concluded that a significative proportion of NUD patients had lowered thresholds for mechano stimulation of stomach and oesophagus at the time that both tests were done. Such alterations support the hypothesis that a more general mechano-sensitivity alteration is present in patients with NUD.

A framework for analyzing the impact of data integrity/quality on electricity market operations

NASA Astrophysics Data System (ADS)

Choi, Dae Hyun

This dissertation examines the impact of data integrity/quality in the supervisory control and data acquisition (SCADA) system on real-time locational marginal price (LMP) in electricity market operations. Measurement noise and/or manipulated sensor errors in a SCADA system may mislead system operators about real-time conditions in a power system, which, in turn, may impact the price signals in real-time power markets. This dissertation serves as a first attempt to analytically investigate the impact of bad/malicious data on electric power market operations. In future power system operations, which will probably involve many more sensors, the impact of sensor data integrity/quality on grid operations will become increasingly important. The first part of this dissertation studies from a market participant's perspective a new class of malicious data attacks on state estimation, which subsequently influences the result of the newly emerging look-ahead dispatch models in the real-time power market. In comparison with prior work of cyber-attack on static dispatch where no inter-temporal ramping constraint is considered, we propose a novel attack strategy, named ramp-induced data (RID) attack, with which the attacker can manipulate the limits of ramp constraints of generators in look-ahead dispatch. It is demonstrated that the proposed attack can lead to financial profits via malicious capacity withholding of selected generators, while being undetected by the existing bad data detection algorithm embedded in today's state estimation software. In the second part, we investigate from a system operator's perspective the sensitivity of locational marginal price (LMP) with respect to data corruption-induced state estimation error in real-time power market. Two data corruption scenarios are considered, in which corrupted continuous data (e.g., the power injection/flow and voltage magnitude) falsify power flow estimate whereas corrupted discrete data (e.g., the on/off status of a circuit breaker) do network topology estimate, thus leading to the distortion of LMP. We present an analytical framework to quantify real-time LMP sensitivity subject to continuous and discrete data corruption via state estimation. The proposed framework offers system operators an analytical tool to identify economically sensitive buses and transmission lines to data corruption as well as find sensors that impact LMP changes significantly. This dissertation serves as a first step towards rigorous understanding of the fundamental coupling among cyber, physical and economical layers of operations in future smart grid.

76 FR 28505 - Okanogan Public Utility District No. 1 of Okanogan County, WA; Notice of Availability of Draft...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-17

....5 miles of new and upgraded access roads. The Enloe Project would operate automatically in a run-of... run-of-river and implementing agency-recommended ramping rates downstream of the project during... effects on geology and soils and water quality. Run-of-river operation would minimize effects on aquatic...

77 FR 21091 - Alabama Power Company; Notice of Application for Amendment of License and Soliciting Comments...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-09

... characters, without prior registration, using the eComment system at http://www.ferc.gov/docs-filing/ecomment... applicant proposes to construct a 20-ft wide and approximately 187-ft long concrete boat ramp with courtesy dock on each side of the ramp. Ninety-four feet of the proposed boat ramp will be within the project...

Ramp compression of magnesium oxide to 234 GPa

DOE PAGES

Wang, Jue; Smith, R. F.; Coppari, F.; ...

2014-05-07

Single-crystal magnesium oxide (MgO) samples were ramp compressed to above 200 GPa pressure at the Omega laser facility. Multi-stepped MgO targets were prepared using lithography and wet etching techniques. Free surface velocities of ramp-compressed MgO were measured with a VISAR. The sound velocity and stress-density response were determined using an iterative Lagrangian analysis. The measured equation of state is consistent with expectations from previous shock and static data as well as with a recent X-ray diffraction measurement under ramp loading. The peak elastic stresses observed in our samples had amplitudes of 3-5.5 GPa, decreasing with propagation distance.

High altitude chemically reacting gas particle mixtures. Volume 3: Computer code user's and applications manual. [rocket nozzle and orbital plume flow fields

NASA Technical Reports Server (NTRS)

Smith, S. D.

1984-01-01

A users manual for the RAMP2 computer code is provided. The RAMP2 code can be used to model the dominant phenomena which affect the prediction of liquid and solid rocket nozzle and orbital plume flow fields. The general structure and operation of RAMP2 are discussed. A user input/output guide for the modified TRAN72 computer code and the RAMP2F code is given. The application and use of the BLIMPJ module are considered. Sample problems involving the space shuttle main engine and motor are included.

2. Overview showing Medical Detachment Barracks on both Ramp No. ...

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

2. Overview showing Medical Detachment Barracks on both Ramp No. 5 (left buildings) and Ramp No. 6 (right buildings). View is to west from roof of Corridor A. Note that a pedestrian sidewalk separates buildings instead of a street for automobiles. In left foreground is the north end of Building No. 9962-B; followed by the north B-sides of Buildings Nos. 9963, 9964, 9965, 9966, 9967 and 9968 on Ramp No. 5. Large white building in far distance is a barracks on the other side of Wilson Avenue. - Madigan Hospital, Medical Detachment Barracks, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

The role of temperature ramp-up time before barrier layer growth in optical and structural properties of InGaN/GaN multi-quantum wells

NASA Astrophysics Data System (ADS)

Xing, Yao; Zhao, Degang; Jiang, Desheng; Liu, Zongshun; Zhu, Jianjun; Chen, Ping; Yang, Jing; Liu, Wei; Liang, Feng; Liu, Shuangtao; Zhang, Liqun; Wang, Wenjie; Li, Mo; Zhang, Yuantao; Du, Guotong

2018-05-01

In InGaN/GaN multi-quantum wells (MQWs), a low temperature cap (LT-cap) layer is grown between the InGaN well layer and low temperature GaN barrier layer. During the growth, a temperature ramp-up and ramp-down process is added between LT-cap and barrier layer growth. The effect of temperature ramp-up time duration on structural and optical properties of quantum wells is studied. It is found that as the ramp-up time increases, the Indium floating layer on the top of the well layer can be diminished effectively, leading to a better interface quality between well and barrier layers, and the carrier localization effect is enhanced, thereby the internal quantum efficiency (IQE) of QWs increases surprisingly. However, if the ramp-up time is too long, the carrier localization effect is weaker, which may increase the probabilities of carriers to meet with nonradiative recombination centers. Meanwhile, more nonradiative recombination centers will be introduced into well layers due to the indium evaporation. Both of them will lead to a reduction of internal quantum efficiency (IQE) of MQWs.

STC1 interference on calcitonin family of receptors signaling during osteoblastogenesis via adenylate cyclase inhibition.

PubMed

Terra, Silvia R; Cardoso, João Carlos R; Félix, Rute C; Martins, Leo Anderson M; Souza, Diogo Onofre G; Guma, Fatima C R; Canário, Adelino Vicente M; Schein, Vanessa

2015-03-05

Stanniocalcin 1 (STC1) and calcitonin gene-related peptide (CGRP) are involved in bone formation/remodeling. Here we investigate the effects of STC1 on functional heterodimer complex CALCRL/RAMP1, expression and activity during osteoblastogenesis. STC1 did not modify CALCRL and ramp1 gene expression during osteoblastogenesis when compared to controls. However, plasma membrane spatial distribution of CALCRL/RAMP1 was modified in 7-day pre-osteoblasts exposed to either CGRP or STC1, and both peptides induced CALCRL and RAMP1 assembly. CGRP, but not STC1 stimulated cAMP accumulation in 7-day osteoblasts and in CALCRL/RAMP1 transfected HEK293 cells. Furthermore, STC1 inhibited forskolin stimulated cAMP accumulation of HEK293 cells, but not in CALCRL/RAMP1 transfected HEK293 cells. However, STC1 inhibited cAMP accumulation in calcitonin receptor (CTR) HEK293 transfected cells stimulated by calcitonin. In conclusion, STC1 signals through inhibitory G-protein modulates CGRP receptor spatial localization during osteoblastogenesis and may function as a regulatory factor interacting with calcitonin peptide members during bone formation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The Effect of Micro-ramps on Supersonic Flow over a Forward-Facing Step

NASA Astrophysics Data System (ADS)

Zhang, Qing-Hu; Yi, Shi-He; Zhu, Yang-Zhu; Chen, Zhi; Wu, Yu

2013-04-01

The effect of micro-ramp control on fully developed turbulent flow over a forward-facing step (FFS) is investigated in a supersonic low-noise wind tunnel at Mach number 3 using nano-tracer planar laser scattering (NPLS) and supersonic particle image velocimetry (PIV) techniques. High spatiotemporal resolution images and the average velocity profiles of supersonic flow over the FFS with and without the control of the micro-ramps are captured. The fine structures of both cases, including the coherent structures of fully developed boundary layer and the large-scale hairpin-like vortices originated from the micro-ramps as well as the interaction of shock waves with the large-scale structures, are revealed and compared. Based on the time-correlation images, the temporal and spatial evolutionary characteristics of the coherent structures are investigated. It is beneficial to understand the dynamic mechanisms of the separated flow and the control mechanisms of the micro-ramps. The size of the separation region is determined by the NPLS and PIV. The results indicate that the control of the micro-ramps is capable of delaying the separation and diminishing the extent of recirculation zone.

Flat-ramp vs. convex-concave thrust geometries in a deformable hanging wall: new insights from analogue modeling experiments

NASA Astrophysics Data System (ADS)

Almeida, Pedro; Tomas, Ricardo; Rosas, Filipe; Duarte, Joao; Terrinha, Pedro

2015-04-01

Different modes of strain accommodation affecting a deformable hanging-wall in a flat-ramp-flat thrust system were previously addressed through several (sandbox) analog modeling studies, focusing on the influence of different variables, such as: a) thrust ramp dip angle and friction (Bonini et al, 2000); b) prescribed thickness of the hanging-wall (Koy and Maillot, 2007); and c) sin-thrust erosion (compensating for topographic thrust edification, e.g. Persson and Sokoutis, 2002). In the present work we reproduce the same experimental procedure to investigate the influence of two different parameters on hanging-wall deformation: 1) the geometry of the thrusting surface; and 2) the absence of a velocity discontinuity (VD) that is always present in previous similar analogue modeling studies. Considering the first variable we use two end member ramp geometries, flat-ramp-flat and convex-concave, to understand the control exerted by the abrupt ramp edges in the hanging-wall stress-strain distribution, comparing the obtain results with the situation in which such edge singularities are absent (convex-concave thrust ramp). Considering the second investigated parameter, our motivation was the recognition that the VD found in the different analogue modeling settings simply does not exist in nature, despite the fact that it has a major influence on strain accommodation in the deformable hanging-wall. We thus eliminate such apparatus artifact from our models and compare the obtained results with the previous ones. Our preliminary results suggest that both investigated variables play a non-negligible role on the structural style characterizing the hanging-wall deformation of convergent tectonic settings were such thrust-ramp systems were recognized. Acknowledgments This work was sponsored by the Fundação para a Ciência e a Tecnologia (FCT) through project MODELINK EXPL/GEO-GEO/0714/2013. Pedro Almeida wants to thank to FCT for the Ph.D. grant (SFRH/BD/52556/2014) under the Doctoral Program EarthSystems in IDL/UL. References Bonini, M., Sokoutis, D., Mulugeta, G., Katrivanos, E. (2000) - Modelling hanging wall accommodation above rigid thrust ramps. Journal of Structural Geology, 22, pp. 1165-1179. Persson, K. & Sokoutis, D (2002) - Analogue models of orogenic wedges controlled by erosion. Tectonophysics, 356, pp. 323- 336. Koy, H. & Bertrand, M. (2007) - Tectonic thickening of hanging-wall units over a ramp.Journal of Structural Geology, 29, pp. 924-932.

Building a viable decollement geometry for the Central Nepal Himalaya through integrating surface geology, thermochronology and data from the 2015 Gorkha Earthquake

NASA Astrophysics Data System (ADS)

Ghoshal, S.; McQuarrie, N.; Robinson, D. M.; Olree, E.; Valentino, C.; Olsen, J.

2017-12-01

Recent field mapping in the Central Himalaya revealed a marked change in the location and orientation of exposed Greater Himalayan rocks around the epicenter of the April 2015 Gorkha earthquake, arguing for a lateral structure in the Main Himalayan Thrust (MHT). The earthquake provided new insight into the geometry of the MHT, but left the position and depth of the mid-crustal ramp in dispute. Combining new field data with existing thermochronometric data from the region emphasizes that both the mapped geology and young cooling ages step abruptly southward from east to west, immediately adjacent to the earthquake epicenter. The distribution of cooling ages is strongly influenced by the location of ramps in the decollement surface, as the vertical component of uplift concentrates exhumation over the ramp, producing the youngest ages there. We propose that the existence and location of frontal and lateral ramps can be evaluated using the regional distribution of thermochronometric ages. Sequentially deformed cross-sections present a model of how structurally induced uplift varies in time and space, as well as a predicted geometry of the active, modern fault. We created new balanced cross-sections, constrained by surface geology and the proposed decollement geometries. For an accurate representation of the subsurface, the geometries must reproduce cooling ages measured at the surface. Each cross section was sequentially deformed, allowing for flexure and erosion. The resulting displacement field was used to predict cooling ages for muscovite 40Ar/39Ar, zircon (U-Th)/He, and apatite fission-track, using the thermokinematic model Pecube. The different closure temperatures for these systems allow them to represent different times and locations of exhumation driven by evolving fault geometries. The modeled cooling ages are the cumulative effect of the entire deformational sequence. However, the ages are particularly sensitive to the modern active decollement fault geometry, allowing us to evaluate the different proposed cross-section geometries, and identify the best match to the regional distribution of cooling ages. We argue that this final geometry is the most accurate representation of the subsurface, being constrained by surface geology, thermochronological ages, and data from the earthquake.

Risk assessment in ramps for heavy vehicles--A French study.

PubMed

Cerezo, Veronique; Conche, Florence

2016-06-01

This paper presents the results of a study dealing with the risk for heavy vehicles in ramps. Two approaches are used. On one hand, statistics are applied on several accidents databases to detect if ramps are more risky for heavy vehicles and to define a critical value for longitudinal slope. χ(2) test confirmed the risk in ramps and statistical analysis proved that a longitudinal slope superior to 3.2% represents a higher risk for heavy vehicles. On another hand, numerical simulations allow defining the speed profile in ramps for two types of heavy vehicles (tractor semi-trailer and 2-axles rigid body) and different loads. The simulations showed that heavy vehicles must drive more than 1000 m on ramps to reach their minimum speed. Moreover, when the slope is superior to 3.2%, tractor semi-trailer presents a strong decrease of their speed until 50 km/h. This situation represents a high risk of collision with other road users which drive at 80-90 km/h. Thus, both methods led to the determination of a risky configuration for heavy vehicles: ramps with a length superior to 1000 m and a slope superior to 3.2%. An application of this research work concerns design methods and guidelines. Indeed, this study provides threshold values than can be used by engineers to make mandatory specific planning like a lane for slow vehicles. Copyright © 2016 Elsevier Ltd. All rights reserved.

PDR with a Foot-Mounted IMU and Ramp Detection

PubMed Central

Jiménez, Antonio R.; Seco, Fernando; Zampella, Francisco; Prieto, José C.; Guevara, Jorge

2011-01-01

The localization of persons in indoor environments is nowadays an open problem. There are partial solutions based on the deployment of a network of sensors (Local Positioning Systems or LPS). Other solutions only require the installation of an inertial sensor on the person’s body (Pedestrian Dead-Reckoning or PDR). PDR solutions integrate the signals coming from an Inertial Measurement Unit (IMU), which usually contains 3 accelerometers and 3 gyroscopes. The main problem of PDR is the accumulation of positioning errors due to the drift caused by the noise in the sensors. This paper presents a PDR solution that incorporates a drift correction method based on detecting the access ramps usually found in buildings. The ramp correction method is implemented over a PDR framework that uses an Inertial Navigation algorithm (INS) and an IMU attached to the person’s foot. Unlike other approaches that use external sensors to correct the drift error, we only use one IMU on the foot. To detect a ramp, the slope of the terrain on which the user is walking, and the change in height sensed when moving forward, are estimated from the IMU. After detection, the ramp is checked for association with one of the existing in a database. For each associated ramp, a position correction is fed into the Kalman Filter in order to refine the INS-PDR solution. Drift-free localization is achieved with positioning errors below 2 meters for 1,000-meter-long routes in a building with a few ramps. PMID:22163701

RHIC Au beam in Run 2014

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

Zhang, S. Y.

Au beam at the RHIC ramp in run 2014 is reviewed together with the run 2011 and run 2012. Observed bunch length and longitudinal emittance are compared with the IBS simulations. The IBS growth rate of the longitudinal emittance in run 2014 is similar to run 2011, and both are larger than run 2012. This is explained by the large transverse emittance at high intensity observed in run 2012, but not in run 2014. The big improvement of the AGS ramping in run 2014 might be related to this change. The importance of the injector intensity improvement in run 2014more » is emphasized, which gives rise to the initial luminosity improvement of 50% in run 2014, compared with the previous Au-Au run 2011. In addition, a modified IBS model, which is calibrated using the RHIC Au runs from 9.8 GeV/n to 100 GeV/n, is presented and used in the study.« less

29 CFR 1918.25 - Bridge plates and ramps (See also § 1918.86).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Bridge plates and ramps (See also § 1918.86). 1918.25... Means of Access § 1918.25 Bridge plates and ramps (See also § 1918.86). (a) Bridge and car plates (dockboards). Bridge and car plates used afloat shall be well maintained and shall: (1) Be strong enough to...

Using archived ITS data to measure the operational benefits of a system-wide adaptive ramp metering system : appendix online\\0x20106: OR\\0x2010217 NB time-space speed contour plots with meter activations.

DOT National Transportation Integrated Search

2008-12-01

Programmable logic controllers (PLCs) were installed at several key ramps with the assistance of the City of Portland and used to capture additional data about ramp operations that are not otherwise logged. The data include include the activation and...

40 CFR 1045.505 - How do I test engines using discrete-mode or ramped-modal duty cycles?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I test engines using discrete... MARINE ENGINES AND VESSELS Test Procedures § 1045.505 How do I test engines using discrete-mode or ramped... allow you to perform tests with either discrete-mode or ramped-modal sampling. You must use the modal...

29 CFR 1918.25 - Bridge plates and ramps (See also § 1918.86).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Bridge plates and ramps (See also § 1918.86). 1918.25... Means of Access § 1918.25 Bridge plates and ramps (See also § 1918.86). (a) Bridge and car plates (dockboards). Bridge and car plates used afloat shall be well maintained and shall: (1) Be strong enough to...

Plasma Gradient Piston: a new approach to precision pulse shaping

NASA Astrophysics Data System (ADS)

Prisbrey, Shon T.

2011-10-01

We have successfully developed a method to create shaped pressure drives from large shocks that can be applied to a wide variety of experimental platforms. The method consists of transforming a large shock or blast wave into a ramped pressured drive by utilizing a graded density reservoir that unloads across a gap and stagnates against the sample being studied. The utilization of a graded density reservoir, different materials, and a gap transforms the energy in the initial large shock into a quasi-isentropic ramped compression. Control of the ramp history is via the size of the initial shock, the chosen reservoir materials, their densities, the thickness of each density layer, and the gap size. There are two keys to utilizing this approach to create ramped drives: the ability to produce a large shock, and making the layered density reservoir. A number of facilities can produce the strong initial shock (Z, Omega, NIF, Phoenix, high explosives, NIKE, LMJ, pulsed power,...). We have demonstrated ramped drives from 0.5 to 1.5 Mbar utilizing a large shock created at the Omega laser facility. We recently concluded a pair of NIF drive shots where we successfully converted a hohlraum-generated shock into a stepped, ramped pressure drive with a peak pressure of ~4 - 5 Mbar in a Ta sample. We will explain the basic concepts needed for producing a ramped pressure drive, compare experimental data with simulations from Omega (Pmax ~ 1 Mbar) and NIF (Pmax ~ 5-10 Mbar), and present designs for ramped, staged-shock designs up to Pmax ~ 30 Mbar. The approach that we have developed enables precision pulse shaping of the drive (applied pressure vs. time) via target characteristics, as opposed to tailoring laser power vs time or Z-pinch facility current vs time. This enables ramped, quasi-isentropic materials studies to be performed on a wide variety of HED facilities. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-490532.

[Prediction and influence factors of the ramp's noise of the entrance or exit of garages].

PubMed

Di, Guo-Qing; Zhang, Bang-Jun

2005-09-01

Some typical entrances/exits of the underground garages are chosen in urban residential areas. On the basis of the optimization of the positions of the noise sampling points and the groupings of the synchronous sampling points, by means of the acoustical analysis of the noise samples, the relation of the correlative factors, among the ramps' noise of the entrances or exits of the garages, the structure, grade, shape of the ramps, upgrade and downgrade, is studied. The prediction model of the ramp's noise influence of the entrance or exit of the garage is established through amending the noise influence of the entrance or exit of the even concrete road.

Supersonic compressor

DOEpatents

Lawlor, Shawn P [Bellevue, WA; Novaresi, Mark A [San Diego, CA; Cornelius, Charles C [Kirkland, WA

2008-02-26

A gas compressor based on the use of a driven rotor having an axially oriented compression ramp traveling at a local supersonic inlet velocity (based on the combination of inlet gas velocity and tangential speed of the ramp) which forms a supersonic shockwave axially, between adjacent strakes. In using this method to compress inlet gas, the supersonic compressor efficiently achieves high compression ratios while utilizing a compact, stabilized gasdynamic flow path. Operated at supersonic speeds, the inlet stabilizes an oblique/normal shock system in the gasdyanamic flow path formed between the gas compression ramp on a strake, the shock capture lip on the adjacent strake, and captures the resultant pressure within the stationary external housing while providing a diffuser downstream of the compression ramp.

Shock formation and the ideal shape of ramp compression waves

NASA Astrophysics Data System (ADS)

Swift, Damian C.; Kraus, Richard G.; Loomis, Eric N.; Hicks, Damien G.; McNaney, James M.; Johnson, Randall P.

2008-12-01

We derive expressions for shock formation based on the local curvature of the flow characteristics during dynamic compression. Given a specific ramp adiabat, calculated for instance from the equation of state for a substance, the ideal nonlinear shape for an applied ramp loading history can be determined. We discuss the region affected by lateral release, which can be presented in compact form for the ideal loading history. Example calculations are given for representative metals and plastic ablators. Continuum dynamics (hydrocode) simulations were in good agreement with the algebraic forms. Example applications are presented for several classes of laser-loading experiment, identifying conditions where shocks are desired but not formed, and where long-duration ramps are desired.

Plasma-Assisted Control of Mach-2 Flowfield over Ramp Geometry

NASA Astrophysics Data System (ADS)

Watanabe, Yasumasa; Leonov, Sergey B.; Houpt, Alec; Hedlund, Brock E.; Elliott, Skye

2017-10-01

This study examined the effect of Reynolds number on plasma-assisted flow control ahead of a compression ramp geometry in Mach-2 supersonic flow. The experiments were conducted in the supersonic wind tunnel SBR-50 at the University of Notre Dame. Stagnation temperature and pressure were varied as T0=294-500K and P0=1-3bar to attain Reynolds number ranging from 3.4×105-2.2×106. Ramp pressure measurements, schlieren visualization, and high-speed camera imaging were used for the evaluation of plasma-assisted flow control effects. A linear dependency was found between the ramp pressure change per averaged plasma power and Reynolds number.

Experimental investigation of a 0.15 scale model of a conformal variable-ramp inlet for the F-16 airplane

NASA Technical Reports Server (NTRS)

Hawkins, J. E.

1980-01-01

A 0.15 scale model of a proposed conformal variable-ramp inlet for the Multirole Fighter was tested from Mach 0.8 to 2.2 at a wide range of angles of attack and sideslip. Inlet ramp angle was varied to optimize ramp angle as a function of engine airflow, Mach number, angle of attack, and angle of sideslip. Several inlet configuration options were investigated to study their effects on inlet operation and to establish the final flight configuration. These variations were cowl sidewall cutback, cowl lip bluntness, boundary layer bleed, and first-ramp leading edge shape. Diagnostic and engine face instrumentation were used to evaluate inlet operation at various inlet stations and at the inlet/engine interface. Pressure recovery and stability of the inlet were satisfactory for the proposed application. On the basis of an engine stability audit of the worst-case instantaneous distortion patterns, no inlet/engine compatibility problems are expected for normal operations.

Tamping Ramping: Algorithmic, Implementational, and Computational Explanations of Phasic Dopamine Signals in the Accumbens

PubMed Central

Lloyd, Kevin; Dayan, Peter

2015-01-01

Substantial evidence suggests that the phasic activity of dopamine neurons represents reinforcement learning’s temporal difference prediction error. However, recent reports of ramp-like increases in dopamine concentration in the striatum when animals are about to act, or are about to reach rewards, appear to pose a challenge to established thinking. This is because the implied activity is persistently predictable by preceding stimuli, and so cannot arise as this sort of prediction error. Here, we explore three possible accounts of such ramping signals: (a) the resolution of uncertainty about the timing of action; (b) the direct influence of dopamine over mechanisms associated with making choices; and (c) a new model of discounted vigour. Collectively, these suggest that dopamine ramps may be explained, with only minor disturbance, by standard theoretical ideas, though urgent questions remain regarding their proximal cause. We suggest experimental approaches to disentangling which of the proposed mechanisms are responsible for dopamine ramps. PMID:26699940

A reliable method to grow vertically-aligned silicon nanowires by a novel ramp-cooling process

NASA Astrophysics Data System (ADS)

Ho, Tzuen-Wei; Hong, Franklin Chau-Nan

2012-08-01

We have grown silicon nanowires (SiNWs) on Si (1 1 1) substrates by gold-catalyzed vapor-liquid-solid (VLS) process using tetrachlorosilane (SiCl4) in a hot-wall chemical vapor deposition reactor. Even under the optimized conditions including H2 annealing to reduce the surface native oxide, epitaxial SiNWs of 150-200 nm in diameter often grew along all four <1 1 1> family directions with one direction vertical and three others inclined to the surface. Therefore, the growth of high degree ordered SiNW arrays along [1 1 1] only was attempted on Au-coated Si (1 1 1) by a ramp-cooling process utilizing the liquid phase epitaxy (LPE) mechanism. The Au-coated Si substrate was first annealed in H2 at 650 °C to form Au-Si alloy nanoparticles, and then ramp-cooled at a controlled rate to precipitate epitaxial Si seeds on the substrate based on LPE mechanism. The substrate was further heated in SiCl4/H2 to 850 °C for the VLS growths of SiNWs on the Si seeds. Thus, almost 100% vertically-aligned SiNWs along [1 1 1] only could be reproducibly grown on Si (1 1 1), without using a template or patterning the metal catalyst. The high-density vertically-aligned SiNWs have good potentials for solar cells and nano-devices.

Automated Traffic Management System and Method

NASA Technical Reports Server (NTRS)

Glass, Brian J. (Inventor); Spirkovska, Liljana (Inventor); McDermott, William J. (Inventor); Reisman, Ronald J. (Inventor); Gibson, James (Inventor); Iverson, David L. (Inventor)

2000-01-01

A data management system and method that enables acquisition, integration, and management of real-time data generated at different rates, by multiple heterogeneous incompatible data sources. The system achieves this functionality by using an expert system to fuse data from a variety of airline, airport operations, ramp control, and air traffic control tower sources, to establish and update reference data values for every aircraft surface operation. The system may be configured as a real-time airport surface traffic management system (TMS) that electronically interconnects air traffic control, airline data, and airport operations data to facilitate information sharing and improve taxi queuing. In the TMS operational mode, empirical data shows substantial benefits in ramp operations for airlines, reducing departure taxi times by about one minute per aircraft in operational use, translating as $12 to $15 million per year savings to airlines at the Atlanta, Georgia airport. The data management system and method may also be used for scheduling the movement of multiple vehicles in other applications, such as marine vessels in harbors and ports, trucks or railroad cars in ports or shipping yards, and railroad cars in switching yards. Finally, the data management system and method may be used for managing containers at a shipping dock, stock on a factory floor or in a warehouse, or as a training tool for improving situational awareness of FAA tower controllers, ramp and airport operators, or commercial airline personnel in airfield surface operations.

Using archived ITS data to measure the operational benefits of a system-wide adaptive ramp metering system : appendix online\\0x20101 : I\\0x2010205 NB time\\0x2010space speed contour plots with meter activations.

DOT National Transportation Integrated Search

2008-12-01

Programmable logic controllers (PLCs) were installed at several key ramps with the assistance of the City of Portland and used to capture additional data about ramp operations that are not otherwise logged. The data include the activation and deactiv...

Having Fun with a Cordless Mouse

ERIC Educational Resources Information Center

Nunn, John

2016-01-01

A cordless mouse with an added reed switch is used as a wireless data logger to record every time the wheel of a trolley completes a revolution. The limitations of the system in terms of maximum clicking rate and spatial resolution are considered and data obtained from the descent of a trolley down a ramp at various different angles is analysed in…

Numerical investigation of over expanded flow behavior in a single expansion ramp nozzle

NASA Astrophysics Data System (ADS)

Mousavi, Seyed Mahmood; Pourabidi, Reza; Goshtasbi-Rad, Ebrahim

2018-05-01

The single expansion ramp nozzle is severely over-expanded when the vehicle is at low speed, which hinders its ability to provide optimal configurations for combined cycle engines. The over-expansion leads to flow separation as a result of shock wave/boundary-layer interaction. Flow separation, and the presence of shocks themselves, result in a performance loss in the single expansion ramp nozzle, leading to reduced thrust and increased pressure losses. In the present work, the unsteady two dimensional compressible flow in an over expanded single expansion ramp nozzle has been investigated using finite volume code. To achieve this purpose, the Reynolds stress turbulence model and full multigrid initialization, in addition to the Smirnov's method for examining the errors accumulation, have been employed and the results are compared with available experimental data. The results show that the numerical code is capable of predicting the experimental data with high accuracy. Afterward, the effect of discontinuity jump in wall temperature as well as the length of straight ramp on flow behavior have been studied. It is concluded that variations in wall temperature and length of straight ramp change the shock wave boundary layer interaction, shock structure, shock strength as well as the distance between Lambda shocks.

Two-Dimensional Supersonic Nozzle Thrust Vectoring Using Staggered Ramps

NASA Astrophysics Data System (ADS)

Montes, Carlos Fernando

A novel mechanism for vectoring the thrust of a supersonic, air-breathing engine was analyzed numerically using ANSYS Fluent. The mechanism uses two asymmetrically staggered ramps; one placed at the throat, the other positioned at the exit lip of the nozzle. The nozzle was designed using published flow data, isentropic relationships, and piecewise quartic splines. The design was verified numerically and was in fair agreement with the analytical data. Using the steady-state pressure-based solver, along with the realizable kappa - epsilon turbulence model, a total of eighteen simulations were conducted: three ramp lengths at three angles, using two sets of inlet boundary conditions (non-afterburning and afterburning). The vectoring simulations showed that the afterburning flow yields a lower flow deflection distribution, shown by the calculated average deflection angle and area-weighted integrals of the distributions. The data implies that an aircraft can achieve an average thrust vectoring angle of approximately 30° in a given direction with the longest ramp length and largest ramp angle configuration. With increasing ramp angle, the static pressure across the nozzle inlet increased, causing concern for potential negative effects on the engine's turbine. The mechanism, for which a provisional patent application has been filed, will require further work to investigate the maximum possible thrust vectoring angle, including experiments.

The Physics of Traffic

NASA Astrophysics Data System (ADS)

Davis, L. Craig

2006-03-01

Congestion in freeway traffic is an example of self-organization in the language of complexity theory. Nonequilibrium, first-order phase transitions from free flow cause complex spatiotemporal patterns. Two distinct phases of congestion are observed in empirical traffic data--wide moving jams and synchronous flow. Wide moving jams are characterized by stopped or slowly moving vehicles within the jammed region, which widens and moves upstream at 15-20 km/h. Above a critical density of vehicles, a sudden decrease in the velocity of a lead vehicle can initiate a transition from metastable states to this phase. Human behaviors, especially delayed reactions, are implicated in the formation of jams. The synchronous flow phase results from a bottleneck such as an on-ramp. Thus, in contrast to a jam, the downstream front is pinned at a fixed location. The name of the phase comes from the equilibration (or synchronization) of speed and flow rate across all lanes caused by frequent vehicle lane changes. Synchronous flow occurs when the mainline flow and the rate of merging from an on-ramp are sufficiently large. Large-scale simulations using car-following models reproduce the physical phenomena occurring in traffic and suggest methods to improve flow and mediate congestion.

Strengthened MILP formulation for certain gas turbine unit commitment problems

DOE PAGES

Pan, Kai; Guan, Yongpei; Watson, Jean -Paul; ...

2015-05-22

In this study, we derive a strengthened MILP formulation for certain gas turbine unit commitment problems, in which the ramping rates are no smaller than the minimum generation amounts. This type of gas turbines can usually start-up faster and have a larger ramping rate, as compared to the traditional coal-fired power plants. Recently, the number of this type of gas turbines increases significantly due to affordable gas prices and their scheduling flexibilities to accommodate intermittent renewable energy generation. In this study, several new families of strong valid inequalities are developed to help reduce the computational time to solve these typesmore » of problems. Meanwhile, the validity and facet-defining proofs are provided for certain inequalities. Finally, numerical experiments on a modified IEEE 118-bus system and the power system data based on recent studies verify the effectiveness of applying our formulation to model and solve this type of gas turbine unit commitment problems, including reducing the computational time to obtain an optimal solution or obtaining a much smaller optimality gap, as compared to the default CPLEX, when the time limit is reached with no optimal solutions obtained.« less

Dielectric Characterization of Mylar and The Effects of Doping Processes.

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

Belcher, Cami Beth

2016-11-01

Mylar® polymer is a bi-axially oriented polyethylene terephthalate (PET) polymer film used widely as a dielectric, specifically in capacitors. The dielectric characteristics of Mylar have been well studied and documented over the years; however, many of the mechanisms responsible for dielectric breakdown and failure are not understood for modified versions of the material. Previous studies on Mylar confirm that factors such as temperature, humidity, and voltage ramp rates can also have a significant effect on the dielectric properties and measurement of the dielectric properties. This study seeks to determine how dielectric properties, including permittivity, dielectric loss, and breakdown strength, aremore » affected by doping of the polymer. To do this, two types of Mylar films, virgin film and film doped with a small-molecule electron-acceptor, are tested. Both types of materials are tested under a variety of environmental and experimental conditions, including testing at elevated temperatures, varying relative humidity, and varying ramp rates in dielectric breakdown testing. Analysis of permittivity, dielectric loss, and breakdown strength will be presented comparing virgin and doped Mylar to gain insight into the effects of doping with electron-acceptor molecules on dielectric properties under these varying environmental and test conditions.« less

Use DNA solutions to model polymer entanglement in flow: simultaneous rheometric and particle-tracking velocimetric measurements

NASA Astrophysics Data System (ADS)

Boukany, Pouyan; Wang, Shi-Qing

2008-03-01

Entangled aqueous DNA solutions are ideal as a model system to examine nonlinear flow features including stress overshoot in startup shear and shear thinning phenomenon. These soft systems can be strongly entangled with 60 entanglement points per chain and a terminal relaxation time as long as 1000 s at 1 % concentration [1-2]. They allow a comparison between the steady state attained with a startup shear and that attained through an ``infinitely'' slow ramping up of the applied shear rate. Indeed, startup shear in the nonlinear (stress plateau) region causes the DNA solutions to yield inhomogeneously, resulting in permanent shear banding. However, the slowly ramped-up shear into the same final rate as applied in startup shear allowed the solutions to avoid shear inhomogeneity. Thus, we demonstrated that it is possible for the final steady states to be different depending on how an entangled system is brought into the same final experimental condition. This result implies that it is ill-defined to pursue conventional constitutive relationship in flow of entangled polymers. [1] Boukany, P. E.; Hu, T. H.; Wang, S. Q. textitMacromolecules 2007, under review. [2] Boukany, P. E.; Wang, S. Q. J. Rheol. 2007, under review.

Evidence Accumulator or Decision Threshold – Which Cortical Mechanism are We Observing?

PubMed Central

Simen, Patrick

2012-01-01

Most psychological models of perceptual decision making are of the accumulation-to-threshold variety. The neural basis of accumulation in parietal and prefrontal cortex is therefore a topic of great interest in neuroscience. In contrast, threshold mechanisms have received less attention, and their neural basis has usually been sought in subcortical structures. Here I analyze a model of a decision threshold that can be implemented in the same cortical areas as evidence accumulators, and whose behavior bears on two open questions in decision neuroscience: (1) When ramping activity is observed in a brain region during decision making, does it reflect evidence accumulation? (2) Are changes in speed-accuracy tradeoffs and response biases more likely to be achieved by changes in thresholds, or in accumulation rates and starting points? The analysis suggests that task-modulated ramping activity, by itself, is weak evidence that a brain area mediates evidence accumulation as opposed to threshold readout; and that signs of modulated accumulation are as likely to indicate threshold adaptation as adaptation of starting points and accumulation rates. These conclusions imply that how thresholds are modeled can dramatically impact accumulator-based interpretations of this data. PMID:22737136

Field-scale forward modelling of a shallow marine carbonate ramp: the Upper Jurassic Arab Formation (onshore Abu Dhabi - UAE)

NASA Astrophysics Data System (ADS)

Marchionda, Elisabetta; Deschamps, Rémy; Nader, Fadi H.; Ceriani, Andrea; Di Giulio, Andrea; Lawrence, David; Morad, Daniel J.

2017-04-01

The stratigraphic record of a carbonate system is the result of the interplay of several local and global factors that control the physical and the biological responses within a basin. Conceptual models cannot be detailed enough to take into account all the processes that control the deposition of sediments. The evaluation of the key controlling parameters on the sedimentation can be investigated with the use of stratigraphic forward models, that permit dynamic and quantitative simulations of the sedimentary basin infill. This work focuses on an onshore Abu Dhabi field (UAE) and it aims to provide a complete picture of the stratigraphic evolution of Upper Jurassic Arab Formation (Fm.). In this study, we started with the definition of the field-scale conceptual depositional model of the Formation, resulting from facies and well log analysis based on five wells. The Arab Fm. could be defined as a shallow marine carbonate ramp, that ranges from outer ramp deposits to supratidal/evaporitic facies association (from bottom to top). With the reconstruction of the sequence stratigraphic pattern and several paleofacies maps, it was possible to suggest multiple directions of progradations at local scale. Then, a 3D forward modelling tool has been used to i) identify and quantify the controlling parameters on geometries and facies distribution of the Arab Fm.; ii) predict the stratigraphic architecture of the Arab Fm.; and iii) integrate and validate the conceptual model. Numerous constraints were set during the different simulations and sensitivity analyses were performed testing the carbonate production, eustatic oscillations and transport parameters. To verify the geological consistency the 3D forward modelling has been calibrated with the available control points (five wells) in terms of thickness and facies distribution.

STRETCH-DEPENDENT SENSITIZATION OF POST-JUNCTIONAL NEURAL EFFECTORS IN COLONIC MUSCLES

PubMed Central

Won, Kyung-Jong; Sanders, Kenton M.; Ward, Sean M.

2012-01-01

Background The colon undergoes distension-induced changes in motor activity as luminal contents or feces increases wall pressure. Input from enteric motor neurons regulates motility. Here we examined stretch-dependent responses in circular muscle strips of murine colon. Methods Length-ramps (6–31μm s−1) were applied in the axis of the circular muscle layer in a controlled manner until 5 mN isometric force was reached. Key Results Length-ramps produced transient membrane potential hyperpolarizations and attenuation of action potential (AP) complexes. Responses were reproducible when ramps were applied every 30s. Stretch-dependent hyperpolarization was blocked by TTX, suggesting AP-dependent release of inhibitory neurotransmitter(s). Atropine did not potentiate stretch-induced hyperpolarizations, but increased compliance of the circular layer. L-NNA inhibited stretch-dependent hyperpolarization and decreased muscle compliance, suggesting release of NO mediates stretch-dependent inhibition. Control membrane potential was restored by the NO donor SNP. Stretch-dependent hyperpolarizations were blocked by L-methionine, an inhibitor of stretch-dependent K+ (SDK) channels in colonic muscles. Loss of ICC, elicited by Kit neutralizing antibody, also inhibited responses to stretch. In presence of L-NNA and apamin, stretch responses became excitatory and were characterized by membrane depolarization and increased AP firing. A neurokinin-1 receptor antagonist inhibited this stretch-dependent increase in excitability. Conclusions & Inferences Our data show that stretch-dependent responses in colonic muscles require tonic firing of enteric inhibitory neurons, but reflex activation of neurons does not appear to be necessary. NO causes activation of SDK channels, and stretch of muscles further activates these channels, explaining the inhibitory response to stretch in colonic muscle strips. PMID:23279087

Cortical Activation Patterns Evoked by Temporally Asymmetric Sounds and Their Modulation by Learning

PubMed Central

Horikawa, Junsei

2017-01-01

When complex sounds are reversed in time, the original and reversed versions are perceived differently in spectral and temporal dimensions despite their identical duration and long-term spectrum-power profiles. Spatiotemporal activation patterns evoked by temporally asymmetric sound pairs demonstrate how the temporal envelope determines the readout of the spectrum. We examined the patterns of activation evoked by a temporally asymmetric sound pair in the primary auditory field (AI) of anesthetized guinea pigs and determined how discrimination training modified these patterns. Optical imaging using a voltage-sensitive dye revealed that a forward ramped-down natural sound (F) consistently evoked much stronger responses than its time-reversed, ramped-up counterpart (revF). The spatiotemporal maximum peak (maxP) of F-evoked activation was always greater than that of revF-evoked activation, and these maxPs were significantly separated within the AI. Although discrimination training did not affect the absolute magnitude of these maxPs, the revF-to-F ratio of the activation peaks calculated at the location where hemispheres were maximally activated (i.e., F-evoked maxP) was significantly smaller in the trained group. The F-evoked activation propagated across the AI along the temporal axis to the ventroanterior belt field (VA), with the local activation peak within the VA being significantly larger in the trained than in the naïve group. These results suggest that the innate network is more responsive to natural sounds of ramped-down envelopes than their time-reversed, unnatural sounds. The VA belt field activation might play an important role in emotional learning of sounds through its connections with amygdala. PMID:28451640

Coupling of laser energy into plasma channels

NASA Astrophysics Data System (ADS)

Dimitrov, D. A.; Giacone, R. E.; Bruhwiler, D. L.; Busby, R.; Cary, J. R.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

2007-04-01

Diffractive spreading of a laser pulse imposes severe limitations on the acceleration length and maximum electron energy in the laser wake field accelerator (LWFA). Optical guiding of a laser pulse via plasma channels can extend the laser-plasma interaction distance over many Rayleigh lengths. Energy efficient coupling of laser pulses into and through plasma channels is very important for optimal LWFA performance. Results from simulation parameter studies on channel guiding using the particle-in-cell (PIC) code VORPAL [C. Nieter and J. R. Cary, J. Comput. Phys. 196, 448 (2004)] are presented and discussed. The effects that density ramp length and the position of the laser pulse focus have on coupling into channels are considered. Moreover, the effect of laser energy leakage out of the channel domain and the effects of tunneling ionization of a neutral gas on the guided laser pulse are also investigated. Power spectral diagnostics were developed and used to separate pump depletion from energy leakage. The results of these simulations show that increasing the density ramp length decreases the efficiency of coupling a laser pulse to a channel and increases the energy loss when the pulse is vacuum focused at the channel entrance. Then, large spot size oscillations result in increased energy leakage. To further analyze the coupling, a differential equation is derived for the laser spot size evolution in the plasma density ramp and channel profiles are simulated. From the numerical solution of this equation, the optimal spot size and location for coupling into a plasma channel with a density ramp are determined. This result is confirmed by the PIC simulations. They show that specifying a vacuum focus location of the pulse in front of the top of the density ramp leads to an actual focus at the top of the ramp due to plasma focusing, resulting in reduced spot size oscillations. In this case, the leakage is significantly reduced and is negligibly affected by ramp length, allowing for efficient use of channels with long ramps.

Effect of initial shock wave voltage on shock wave lithotripsy-induced lesion size during step-wise voltage ramping.

PubMed

Connors, Bret A; Evan, Andrew P; Blomgren, Philip M; Handa, Rajash K; Willis, Lynn R; Gao, Sujuan

2009-01-01

To determine if the starting voltage in a step-wise ramping protocol for extracorporeal shock wave lithotripsy (SWL) alters the size of the renal lesion caused by the SWs. To address this question, one kidney from 19 juvenile pigs (aged 7-8 weeks) was treated in an unmodified Dornier HM-3 lithotripter (Dornier Medical Systems, Kennesaw, GA, USA) with either 2000 SWs at 24 kV (standard clinical treatment, 120 SWs/min), 100 SWs at 18 kV followed by 2000 SWs at 24 kV or 100 SWs at 24 kV followed by 2000 SWs at 24 kV. The latter protocols included a 3-4 min interval, between the 100 SWs and the 2000 SWs, used to check the targeting of the focal zone. The kidneys were removed at the end of the experiment so that lesion size could be determined by sectioning the entire kidney and quantifying the amount of haemorrhage in each slice. The average parenchymal lesion for each pig was then determined and a group mean was calculated. Kidneys that received the standard clinical treatment had a mean (sem) lesion size of 3.93 (1.29)% functional renal volume (FRV). The mean lesion size for the 18 kV ramping group was 0.09 (0.01)% FRV, while lesion size for the 24 kV ramping group was 0.51 (0.14)% FRV. The lesion size for both of these groups was significantly smaller than the lesion size in the standard clinical treatment group. The data suggest that initial voltage in a voltage-ramping protocol does not correlate with renal damage. While voltage ramping does reduce injury when compared with SWL with no voltage ramping, starting at low or high voltage produces lesions of the same approximate size. Our findings also suggest that the interval between the initial shocks and the clinical dose of SWs, in our one-step ramping protocol, is important for protecting the kidney against injury.

Determining a Prony Series for a Viscoelastic Material From Time Varying Strain Data

NASA Technical Reports Server (NTRS)

Tzikang, Chen

2000-01-01

In this study a method of determining the coefficients in a Prony series representation of a viscoelastic modulus from rate dependent data is presented. Load versus time test data for a sequence of different rate loading segments is least-squares fitted to a Prony series hereditary integral model of the material tested. A nonlinear least squares regression algorithm is employed. The measured data includes ramp loading, relaxation, and unloading stress-strain data. The resulting Prony series which captures strain rate loading and unloading effects, produces an excellent fit to the complex loading sequence.

Deformation Rates From Climate Cycles in Marine Synorogenic Turbidites, Jaca Basin, Spanish Pyrenees

NASA Astrophysics Data System (ADS)

Anastasio, D. J.; Kodama, K. P.; Pares, J. M.; Hinnov, L. A.

2007-12-01

Synsedimentary structures provide a link between depositional and deformational processes in orogenic belts. Marine growth strata offer great promise in determining precise long-term deformation rates such as uplift, shortening, fault-slip, and folding rates. Magnetostratigraphy and cyclostratigraphy of the Eocene Arguis Fm., a delta slope deposit and the overlying delta plain Belsue-Atares Fm. monitors the varying pace of deformation at Pico del Aguila, a transverse decollement fold in the south Pyrenean foothills. Anhysteretic remanent magnetization (ARM) data show hierarchical cyclicity at all predicted Milankovitch frequencies. ARM is a proxy for fine-grained detrital magnetite concentration. The age distorting effects of pre-lithification compaction on bed thickness and on the rock and paleomagnetic data series were removed using empirical calibration of anisotropy of anhysteretic remanence magnetization to volume loss from laboratory compaction experiments. The decompacted ARM depth domain was converted to time using an improved magnetostratigraphy within the growth section. Tuning filtered ARM data series to the precession index according to the LA2004 orbital model refined the magnetostratigraphic time scale. The precession-tuned growth strata mapped with precision GPS record variable folding rates at 100skyr timescales for 7 Myr and55° of limb tilt. Folding rates accelerate twice to ~30°/Myr and are punctuated by more gradual decelerations to 0-3°/Myr. Submarine folding rates at Pico del Aguila are attributed to episodic thrusting in the fold core along a roof ramp fault and along the basal decollement. Formation-scale deposition in the Paleogene wedge-top basin responded to tectonic forcing, however, clastic facies patterns in the prodeltaic and slope environments reflect regional uplift controlling sediment supply, sea level variations controlling delta front position and climate forcing (e.g. monsoon strength and frequency, pedogenesis) of runoff variability and ecology in intermountain watersheds. Lithologic parameters sensitive to sea level, such as bed thickness and grain size variations in the turbidite section record strong obliquity and eccentricity modulation, whereas, the ARM derived magnetite concentrations record terrestrial watershed sensitive processes such as aridity and windiness operating at precessional time scales.

Application of Micro-ramp Flow Control Devices to an Oblique Shock Interaction

NASA Technical Reports Server (NTRS)

Hirt, Stefanie; Anderson, Bernhard

2007-01-01

Tests are planned in the 15cm x 15cm supersonic wind tunnel at NASA Glenn to demonstrate the applicability of micro-ramp flow control to the management of shock wave boundary layer interactions. These tests will be used as a database for computational fluid dynamics (CFD) validation and Design of Experiments (DoE) design information. Micro-ramps show potential for mechanically simple and fail-safe boundary layer control.

Using archived ITS data to measure the operational benefits of a system-wide adaptive ramp metering system : appendix online 5 : I-205 NB ramp flow & ML speed-flow plots.

DOT National Transportation Integrated Search

2008-12-01

The appendix includes various ramp flow and ML speed-flow plots, including: I-205 NB, Gladstone MP 11.05; I-205 NB, Gladstone Hway MP 12.94; I-205 NB, Lawnfield MP 13.58; I-205 NB, Sunnybrook MP 14.32; I-205 NB, Sunnyside MP 14.7; I-205 NB, Johnson C...

Slow quench dynamics of a one-dimensional Bose gas confined to an optical lattice.

PubMed

Bernier, Jean-Sébastien; Roux, Guillaume; Kollath, Corinna

2011-05-20

We analyze the effect of a linear time variation of the interaction strength on a trapped one-dimensional Bose gas confined to an optical lattice. The evolution of different observables such as the experimentally accessible on site particle distribution are studied as a function of the ramp time by using time-dependent numerical techniques. We find that the dynamics of a trapped system typically displays two regimes: For long ramp times, the dynamics is governed by density redistribution, while at short ramp times, local dynamics dominates as the evolution is identical to that of an homogeneous system. In the homogeneous limit, we also discuss the nontrivial scaling of the energy absorbed with the ramp time.

Non-stationary self-focusing of intense laser beam in plasma using ramp density profile

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

Habibi, M.; Ghamari, F.

2011-10-15

The non-stationary self-focusing of high intense laser beam in under-dense plasma with upward increasing density ramp is investigated. The obtained results show that slowly increasing plasma density ramp is very important in enhancing laser self-focusing. Also, the spot size oscillations of laser beam in front and rear of the pulse for two different density profiles are shown. We have selected density profiles that already were used by Sadighi-Bonabi et al.[Phys. Plasmas 16, 083105 (2009)]. Ramp density profile causes the laser beam to become more focused and penetrations deeps into the plasma by reduction of diffraction effects. Our computations show moremore » reliable results in comparison to the previous works.« less

A second trigeminal CGRP receptor: function and expression of the AMY1 receptor

PubMed Central

Walker, Christopher S; Eftekhari, Sajedeh; Bower, Rebekah L; Wilderman, Andrea; Insel, Paul A; Edvinsson, Lars; Waldvogel, Henry J; Jamaluddin, Muhammad A; Russo, Andrew F; Hay, Debbie L

2015-01-01

Objective The trigeminovascular system plays a central role in migraine, a condition in need of new treatments. The neuropeptide, calcitonin gene-related peptide (CGRP), is proposed as causative in migraine and is the subject of intensive drug discovery efforts. This study explores the expression and functionality of two CGRP receptor candidates in the sensory trigeminal system. Methods Receptor expression was determined using Taqman G protein-coupled receptor arrays and immunohistochemistry in trigeminal ganglia (TG) and the spinal trigeminal complex of the brainstem in rat and human. Receptor pharmacology was quantified using sensitive signaling assays in primary rat TG neurons. Results mRNA and histological expression analysis in rat and human samples revealed the presence of two CGRP-responsive receptors (AMY1: calcitonin receptor/receptor activity-modifying protein 1 [RAMP1]) and the CGRP receptor (calcitonin receptor-like receptor/RAMP1). In support of this finding, quantification of agonist and antagonist potencies revealed a dual population of functional CGRP-responsive receptors in primary rat TG neurons. Interpretation The unexpected presence of a functional non-canonical CGRP receptor (AMY1) at neural sites important for craniofacial pain has important implications for targeting the CGRP axis in migraine. PMID:26125036

Quantitative allochem compositional analysis of Lochkovian-Pragian boundary sections in the Prague Basin (Czech Republic)

NASA Astrophysics Data System (ADS)

Weinerová, Hedvika; Hron, Karel; Bábek, Ondřej; Šimíček, Daniel; Hladil, Jindřich

2017-06-01

Quantitative allochem compositional trends across the Lochkovian-Pragian boundary Event were examined at three sections recording the proximal to more distal carbonate ramp environment of the Prague Basin. Multivariate statistical methods (principal component analysis, correspondence analysis, cluster analysis) of point-counted thin section data were used to reconstruct facies stacking patterns and sea-level history. Both the closed-nature allochem percentages and their centred log-ratio (clr) coordinates were used. Both these approaches allow for distinguishing of lowstand, transgressive and highstand system tracts within the Praha Formation, which show gradual transition from crinoid-dominated facies deposited above the storm wave base to dacryoconarid-dominated facies of deep-water environment below the storm wave base. Quantitative compositional data also indicate progradative-retrogradative trends in the macrolithologically monotonous shallow-water succession and enable its stratigraphic correlation with successions from deeper-water environments. Generally, the stratigraphic trends of the clr data are more sensitive to subtle changes in allochem composition in comparison to the results based on raw data. A heterozoan-dominated allochem association in shallow-water environments of the Praha Formation supports the carbonate ramp environment assumed by previous authors.

Differential baroreflex control of heart rate in sedentary and aerobically fit individuals

NASA Technical Reports Server (NTRS)

Smith, S. A.; Querry, R. G.; Fadel, P. J.; Welch-O'Connor, R. M.; Olivencia-Yurvati, A.; Shi, X.; Raven, P. B.

2000-01-01

PURPOSE: We compared arterial, aortic, and carotid-cardiac baroreflex sensitivity in eight average fit (maximal oxygen uptake, VO2max = 42.2+/-1.9 mL x kg(-1) x min(-1)) and eight high fit (VO2max = 61.9+/-2.2 mL x kg(-1) x min(-1)) healthy young adults. METHODS: Arterial and aortic (ABR) baroreflex functions were assessed utilizing hypo- and hyper-tensive challenges induced by graded bolus injections of sodium nitroprusside (SN) and phenylephrine (PE), respectively. Carotid baroreflex (CBR) sensitivity was determined using ramped 5-s pulses of both pressure and suction delivered to the carotid sinus via a neck chamber collar, independent of drug administration. RESULTS: During vasoactive drug injection, mean arterial pressure (MAP) was similarly altered in average fit (AF) and high fit (HF) groups. However, the heart rate (HR) response range of the arterial baroreflex was significantly attenuated (P < 0.05) in HF (31+/-4 beats x min(-1)) compared with AF individuals (46+/-4 beats x min(-1)). When sustained neck suction and pressure were applied to counteract altered carotid sinus pressure during SN and PE administration, isolating the ABR response, the response range remained diminished (P < 0.05) in the HF population (24+/-3 beats x min(-1)) compared with the AF group (41+/-4 beats x min(-1)). During CBR perturbation, the HF (14+/-1 beats-min(-1)) and AF (16+/-1 beats-min(-1)) response ranges were similar. The arterial baroreflex response range was significantly less than the simple sum of the CBR and ABR (HF, 38+/-3 beats x min(-1) and AF, 57+/-4 beats x min(-1)) in both fitness groups. CONCLUSIONS: These data confirm that reductions in arterial-cardiac reflex sensitivity are mediated by diminished ABR function. More importantly, these data suggest that the integrative relationship between the ABR and CBR contributing to arterial baroreflex control of HR is inhibitory in nature and not altered by exercise training.

Experimental Deformation of Dehydrating Antigorite: Challenging Models of Dehydration Embrittlement

NASA Astrophysics Data System (ADS)

Hirth, Greg; Chernak, Linda

2010-05-01

To test the hypothesis that intermediate depth earthquakes in subduction zones are caused by the dehydration of hydrous phases, we conducted temperature-ramping experiments on antigorite serpentinite. Cold-pressed powdered samples of antigorite were deformed to a high differential stress at 400°C and 1.0 GPa, within the antigorite stability field, where we have shown that deformation localizes. Temperature was then increased at different rates, 1800°C/hr and 180°C/hr, to cross the reaction boundary while the sample continued to deform; samples were deformed at strain rates of 10-4 s-1, 10-5 s-1 and 10-6 s-1. Two additional experiments were conducted in a similar manner at 300°C, 1.5 GPa and 10-5 s-1 but samples remained 'statically' at high stress during the temperature increase. Our results show that although the decrease in stress during temperature ramping is large, stress relaxes stably, even after dehydration. We find that the slopes of the unloading curves are approximately the same for constant values of the ratio (strain rate/ramp rate) and that the unloading slope is greater for higher values of this ratio. In addition, we find that the unloading curves with the greatest slopes are similar to the apparatus compliance, suggesting that we are generating 'slow earthquakes' in our experiments over the course 5 to 10s of minutes. A strain rate stepping experiment indicates that antigorite has velocity strengthening behavior at 700°C and 1.5 GPa suggesting that as soon as an instability develops in the antigorite, the material strengthens sufficiently to not go unstable. Our results thus suggest that antigorite dehydration does not result in 'dehydration embrittlement' but that it may promote slow earthquakes. We have also conducted a preliminary experiment to study the role of effective pressure on deformation behavior after dehydration. A cold-pressed powdered sample of antigorite with a small core of coarse-grained olivine at one end was deformed at 700°C, 1.5 GPa and a strain rate of 10-5 s-1. This sample had a strength of 300 MPa, which is significantly higher than samples deformed at the same conditions without olivine present; strengths were approximately 100 MPa for these samples. We hypothesize that the highly porous and permeable olivine layer provided a reservoir for the water released by the dehydration reaction and suggests that the presence of water causes the strength of antigorite to decrease.

New laparoscopic procedure for left-sided pancreatic cancer-artery-first approach laparoscopic RAMPS using 3D technique.

PubMed

Yamamoto, Michihiro; Zaima, Masazumi; Yamamoto, Hidekazu; Harada, Hideki; Kawamura, Junichiro; Yamada, Masahiro; Yazawa, Tekefumi; Kawasoe, Junya

2017-12-02

For left-sided pancreatic ductal adenocarcinoma (PDAC), radical antegrade modular pancreatosplenectomy (RAMPS) is a reasonable surgical approach for tumor-free margin resection and systemic lymph node clearance. In pancreaticoduodenectomy for PDAC, the superior mesenteric artery (SMA)-first approach (or the "artery-first approach") has become the standard procedure. With improvements in laparoscopic instruments and techniques, some surgeons attempted to apply laparoscopic RAMPS (L-RAMPS) for carefully selected patients with left-sided PDAC. However, owing to several technical difficulties in this procedure, its application remains uncommon. Moreover, the artery-first approach in L-RAMPS has not been reported. Here, we developed the artery-first approach L-RAMPS for left-sided PDAC and have presented the same in this report. Between June 2014 and July 2015, 16 patients with left-sided PDAC were referred to our division for pancreatic resection. The following technique was used for performing L-RAMPS on 3 of the 16 patients (19%). Six trocars were placed. After opening the omental bursa, only the middle segment of the pancreas was initially separated from both the left renal vein and the SMA. We termed this procedure as the "artery-first approach using a dome-shaped dorsomedial dissection (3D) technique." This 3D technique enabled the interruption of the entire arterial supply to the specimen while preserving the venous drainage through the splenic vein for preventing venous congestion. The technique also contributed to the early detection of no tumor infiltration into the SMA and the early determination of posterior dissection plane. After pancreatic neck transection, the splenic artery and vein were divided. Finally, the pancreatic tail and spleen were dissected in a right-to-left direction. All operations were completed without any intraoperative complications. The median blood loss and retrieved lymph node count were 75 mL and 37, respectively, which were superior to those reported by other previous studies on L-RAMPS. All resection margins were free of carcinoma. No severe postoperative complications were observed. The artery-first approach L-RAMPS using 3D technique is safe and feasible to perform. The significance of our proposed procedure is minimal blood loss and precise lymphadenectomy. Therefore, this novel technique may become the preferred treatment for left-sided PDAC in selected cases.

Exploring how sand ramps respond to Quaternary environmental change in Southern Africa

NASA Astrophysics Data System (ADS)

Rowell, Alex; Thomas, David; Bailey, Richard

2014-05-01

The current climate of southern Africa is particularly complex and interesting due to the interaction of several climatic systems. However, reconstructions of how these systems behaved in the past, and how the environment responded, have been hampered by a general paucity of records and poor chronological control. Sand ramps may provide the potential to improve palaeoenvironmental reconstructions of southern Africa (and beyond). Formed against a topographic barrier, sand ramps include a combination of aeolian, fluvial and colluvial deposits in varying proportions. Therefore, they have the potential to record changes in moisture availability, circulation patterns and sediment supply which can be independently dated using luminescence dating. Nevertheless relatively little attention has been paid to these features and thus the environmental controls on their formation are not yet fully understood. In particular, there is debate as to whether they reflect deposition during a 'window of opportunity' in which high-magnitude, low-frequency events are recorded (Bateman et al. 2012) or whether they record more gradual, cyclic climate change (Bertram, 2003) or even if there is a uniform control on their formation. This research aims to investigate how sand ramps respond to environmental change and what they can tell us about the paleoenvironment of southern Africa. This poster displays preliminary results based on initial field investigation. This confirmed sand ramps to be ubiquitous in southern Africa and that they record a complex interaction of aeolian, fluvial and colluvial deposits which appears to differ between sand ramps. Preliminary luminescence dating results and sedimentology are displayed for two sand ramps, one from south west Namibia the other from the Karoo region of South Africa.

COS/FUV Special Recovery

NASA Astrophysics Data System (ADS)

Wheeler, Thomas

2011-10-01

This proposal consists of the steps necessary for turning on and ramping up {in magnitude} the COS FUV high voltage and returning the FUV detector to science operations in a conservative manner after a HV anomalous or burst event {similar to what has been seen on FUSE} shutdown. HSTAR 13305 provides details and timeline of the present shutdown. The complete step-by-step procedure is detailed in the Observing Description, but in summary, the following is done: Groups of sequences with one dayâ??s activities with the QE grid off and one dayâ??s activities with the QE grid on alternate to progressively higher voltages with the QE off group leading by one sequence. The initial HV turn on {Day 1} occurs with the QE grid off; the initial transition from FUV Operate to HVLow is broken into two parts with a 1- hour wait between turning the HV on and ramping to HVLow {SAA}. The next Day 1 visit is 1 hour later, where the HV is turned off by returning the FUV Operate state. After another1-hour wait, the QE grid is turned on, the HV is turned on and the voltage is not ramped. After another 1-hour wait, the HV is turned off returning to FUV Operate. The Day 1 ends with the NSSC-1 COS flag 3 is set to prevent any FUV HV commanding. This is followed by 10 cycles {2 * 5 cycles - one set of cycles with the grid off and one set with the grid on} of HV ramp-ups and returns to FUV Operate {HV off} alternating between grid off and on with the QE off group leading by one HV setting. The HV Commanded Counts for each group of cycles are: 154/151, 160/157, 166/163, 172/169, HVNom {178/175}. {The formula to convert Command Counts to HV is: Volts = {Command Counts * -15.69V} -2500V.}The QE off and QE on cycles are similar except for the QE commanding. One typical QE off cycle is shown below:V14 QE off - Ramp to 166/163After V10 by 2D for analysis. Flag 3 must be cleared to execute. 1. QE off - Turn HV on 2. Ramp to HVLow {100/100} 3. Ramp HV to 166/163 4. DCE RAM dump 5. Dark exposure 6. Wave exposureV15 Return to OperateAfter V14 by 1hr 1. Dark exposure 2. Wave exposure 3. Return to HVLow {100/100} 4. Return to Operate {HV off} 5. DCE RAM Dump 6. Set flag 3In some later cycles with the QE grid on, ground system QasiStates are used to auto-schedule the Operate to HVNom transition. Visits 21 and 25 are going to HVNom {178/175} with the QE grid off and on, respectively. There will be a gap of 2days between grid-off cycles and 2 days between grid-on cycles, offset by 1 day. {See the proposal description for exact timing.}All HV ramp-up will be done at the nominal value of 3 seconds per HV "step" rather than 10 seconds per HV "step" used in SMOV. The concern during SMOV was that gas exposure during launch would allow gas to adsorb on the MCP pore surfaces, and that slower ramping would help to remove this excess gas. This concern no longer exists. The cycle voltage values {for Segments A and B} must be patched in FSW in each cycle prior to the HV ramp commanding. Memory monitors will be set on the patched memory locations. Immediately after obtaining the commanded voltage for that cycle and after return to FUV Operate {HV-off} commanding, the DCE memory will be dumped. After HV ramp-up commanding starting with HVLow and prior to returning to HV off, short DARK exposures {300 secs.} with Stim Rate = 2000 will be obtained and after HV ramp-up commanding starting with levels above HVLow and prior to returning to HV off, short WAVE exposures {60 secs.} will be obtained. After all visits that end with Return to Operate {HV off}, NSSC-1 COS event flag 3 will be set to inhibit any FUV commanding, a.k.a. a â??dead manâ??sâ?? switch. If the flag remains set, subsequent FUV commanding will be skipped. Thus, Operations Requests must be in place to clear the flag prior to those subsequent visits. Real-time monitoring of the telemetry will be used to guide the decisions whether or not to clear the flag. This is also required after the final visit.Throughout the proposal, different â??after byâ?? times, sequence containers, and new alignments are used to optimize flow, schedulability, telemetry and science data analyses, and the clearing of flag 3. The proposal is designed such that the visits and exposures MUST be executed in order.Additionally, all visits are compliant with CARD 3.4.12.8 - COS FUV Mandatory Dwell Time at HVLow {1 hour dwell at HVLow before ramping to a more negative voltage} and CARD 3.4.12.9 â?? COS FUV High Voltage QE Grid Operation {HV must be less negative or equal to the HVLow to switch grid on or off}.

Steady evolution of hillslopes in layered landscapes: self-organization of a numerical hogback

NASA Astrophysics Data System (ADS)

Glade, R.; Anderson, R. S.

2017-12-01

Landscapes developed in layered sedimentary or igneous rocks are common across Earth, as well as on other planets. Features such as hogbacks, exposed dikes, escarpments and mesas exhibit resistant rock layers in tilted, vertical, or horizontal orientation­s adjoining more erodible rock. Hillslopes developed in the erodible rock are typically characterized by steep, linear-to-concave slopes or "ramps" mantled with material derived from the resistant layers, often in the form of large blocks. Our previous work on hogbacks has shown that feedbacks between weathering and transport of the blocks and underlying soft rock are fundamental to their formation; our numerical model incorporating these feedbacks explain the development of commonly observed concave-up slope profiles in the absence of rilling processes. Here we employ an analytic approach to describe the steady behavior of our model, in which hillslope form and erosion rates remain constant in the reference frame of the retreating feature. We first revisit a simple geometric analysis that relates structural dip to erosion rates. We then explore the mechanisms by which our numerical model of hogback evolution self-organizes to meet these geometric expectations. Autogenic adjustment of soil depth, slope and erosion rates enables efficient transport of resistant blocks; this allows erosion of the resistant layer to keep up with base level fall rate, leading to steady evolution of the feature. Analytic solutions relate easily measurable field quantities such as ramp length, slope, block size and resistant layer dip angle to local incision rate, block velocity, and block weathering rate. These equations provide a framework for exploring the evolution of layered landscapes, and pinpoint the processes for which we require a more thorough understanding to predict the evolution of such signature landscapes over time.

An age-structured model of hiv infection that allows for variations in the production rate of viral particles and the death rate of productively infected cells.

PubMed

Nelson, Patrick W; Gilchrist, Michael A; Coombs, Daniel; Hyman, James M; Perelson, Alan S

2004-09-01

Mathematical models of HIV-1 infection can help interpret drug treatment experiments and improve our understanding of the interplay between HIV-1 and the immune system. We develop and analyze an age- structured model of HIV-1 infection that allows for variations in the death rate of productively infected T cells and the production rate of viral particles as a function of the length of time a T cell has been infected. We show that this model is a generalization of the standard differential equation and of delay models previously used to describe HIV-1 infection, and provides a means for exploring fundamental issues of viral production and death. We show that the model has uninfected and infected steady states, linked by a transcritical bifurcation. We perform a local stability analysis of the nontrivial equilibrium solution and provide a general stability condition for models with age structure. We then use numerical methods to study solutions of our model focusing on the analysis of primary HIV infection. We show that the time to reach peak viral levels in the blood depends not only on initial conditions but also on the way in which viral production ramps up. If viral production ramps up slowly, we find that the time to peak viral load is delayed compared to results obtained using the standard (constant viral production) model of HIV infection. We find that data on viral load changing over time is insufficient to identify the functions specifying the dependence of the viral production rate or infected cell death rate on infected cell age. These functions must be determined through new quantitative experiments.

Full-Scale Instrumented Testing and Analysis of Matting Systems for Airfield Parking Ramps and Taxiways

DTIC Science & Technology

2007-12-01

system can only be precisely determined by examining all the materials used in the mat, their structure , orientation, dimensions, etc. and determining...ER D C/ G SL T R- 07 -3 3 Full-Scale Instrumented Testing and Analysis of Matting Systems for Airfield Parking Ramps and Taxiways Chad...ERDC/GSL TR-07-33 December 2007 Full-Scale Instrumented Testing and Analysis of Matting Systems for Airfield Parking Ramps and Taxiways Chad A

T-Craft Seabase Ramp Loads Model Test Data Report

DTIC Science & Technology

2010-12-01

INTRODUCTION 1 TEST CONDITION MATRIX 2 MODEL DESCRIPTIONS 9 LMSR Model 15 Ramp Models 17 MODEL TEST SETUP 18 Side-by-Side Hull Configuration 19... INTRODUCTION The Office of Naval Research (ONR) sponsored a multiple bodied seakeeping model test designed to investigate vessel motions and loads on the hinge...C. 3. Side-by-Side configuration 137 Ramp Load cell 1.88 27.49 -CG ft I ^ -Hinged Connection 3.00 from CL to jauge • oad ce LMSR

Gap Detection in School-Age Children and Adults: Center Frequency and Ramp Duration

PubMed Central

Porter, Heather L.; Hall, Joseph W.; Grose, John H.

2017-01-01

Purpose The age at which gap detection becomes adultlike differs, depending on the stimulus characteristics. The present study evaluated whether the developmental trajectory differs as a function of stimulus frequency region or duration of the onset and offset ramps bounding the gap. Method Thresholds were obtained for wideband noise (500–4500 Hz) with 4- or 40-ms raised-cosine ramps and for a 25-Hz-wide low-fluctuation narrowband noise centered on either 500 or 5000 Hz with 40-ms ramps. Stimuli were played continuously at 70 dB SPL, and the task was to indicate which of 3 intervals contained a gap. Listeners were 5.2- to 15.1-year-old children (n = 40) and adults (n = 10) with normal hearing. Results Regardless of listener age, gap detection thresholds for the wideband noise tended to be lower when gaps were shaped using 4-ms rather than 40-ms ramps. Thresholds also tended to be lower for the low-fluctuation narrowband noise centered on 5000 Hz than 500 Hz. Performance reached adult levels after 11 years of age for all 4 stimuli. Maturation was not uniform across individuals, however; a subset of young children performed like adults, including some 5-year-olds. Conclusion For these stimuli, the developmental trajectory was similar regardless of narrowband noise center frequency or wideband noise onset and offset ramp duration. PMID:28056469

Shock-Ramp Loading of Tin and Aluminum

NASA Astrophysics Data System (ADS)

Seagle, Christopher; Davis, Jean; Martin, Matthew; Hanshaw, Heath

2013-06-01

Equation of state properties for materials off the principle Hugoniot and isentrope are currently poorly constrained. The ability to directly probe regions of phase space between the Hugoniot and isentrope under dynamic loading will greatly improve our ability to constrain equation of state properties under a variety of conditions and study otherwise inaccessible phase transitions. We have developed a technique at Sandia's Z accelerator to send a steady shock wave through a material under test, and subsequently ramp compress from the Hugoniot state. The shock-ramp experimental platform results in a unique loading path and enables probing of equation of state properties in regions of phase space otherwise difficult to access in dynamic experiments. A two-point minimization technique has been developed for the analysis of shock-ramp velocity data. The technique correctly accounts for the ``initial'' Hugoniot density of the material under test before the ramp wave arrives. Elevated quasi-isentropes have been measured for solid aluminum up to 1.4 Mbar and liquid tin up to 1.1 Mbar using the shock ramp technique. These experiments and the analysis of the resulting velocity profiles will be discussed. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85.

Experimental investigation of the micro-ramp based shock wave and turbulent boundary layer interaction control

NASA Astrophysics Data System (ADS)

Bo, Wang; Weidong, Liu; Yuxin, Zhao; Xiaoqiang, Fan; Chao, Wang

2012-05-01

Using a nanoparticle-based planar laser-scattering technique and supersonic particle image velocimetry, we investigated the effects of micro-ramp control on incident shockwave and boundary-layer interaction (SWBLI) in a low-noise supersonic wind-tunnel with Mach number 2.7 and Reynolds number Rθ = 5845. High spatiotemporal resolution wake structures downstream of the micro-ramps were detected, while a complex evolution process containing a streamwise counter-rotating vortex pair and large-scale hairpin-like vortices with Strouhal number Stδ of about 0.5-0.65 was revealed. The large-scale structures could survive while passing through the SWBLI region. Reflected shockwaves are clearly seen to be distorted accompanied by high-frequency fluctuations. Micro-ramp applications have a distinct influence on flow patterns of the SWBLI field that vary depending on spanwise locations. Both the shock foot and separation line exhibit undulations corresponding with modifications of the velocity distribution of the incoming boundary layer. Moreover, by energizing parts of the boundary flow, the micro-ramp is able to dampen the separation.

Structural insights into the difference in substrate recognition of two mannoside phosphorylases from two GH130 subfamilies.

PubMed

Ye, Yuxin; Saburi, Wataru; Odaka, Rei; Kato, Koji; Sakurai, Naofumi; Komoda, Keisuke; Nishimoto, Mamoru; Kitaoka, Motomitsu; Mori, Haruhide; Yao, Min

2016-03-01

In Ruminococcus albus, 4-O-β-D-mannosyl-D-glucose phosphorylase (RaMP1) and β-(1,4)-mannooligosaccharide phosphorylase (RaMP2) belong to two subfamilies of glycoside hydrolase family 130. The two enzymes phosphorolyze β-mannosidic linkages at the nonreducing ends of their substrates, and have substantially diverse substrate specificity. The differences in their mechanism of substrate binding have not yet been fully clarified. In the present study, we report the crystal structures of RaMP1 with/without 4-O-β-D-mannosyl-d-glucose and RaMP2 with/without β-(1→4)-mannobiose. The structures of the two enzymes differ at the +1 subsite of the substrate-binding pocket. Three loops are proposed to determine the different substrate specificities. One of these loops is contributed from the adjacent molecule of the oligomer structure. In RaMP1, His245 of loop 3 forms a hydrogen-bond network with the substrate through a water molecule, and is indispensible for substrate binding. © 2016 Federation of European Biochemical Societies.

Power ramp induced iodine and cesium redistribution in LWR fuel rods

NASA Astrophysics Data System (ADS)

Sontheimer, F.; Vogl, W.; Ruyter, I.; Markgraf, J.

1980-01-01

Volatile fission product migration in LWR fuel rods which are power ramped above a certain threshold beyond the envelope of their previous power history, plays an important role in stress corrosion cracking of Zircaloy. This may cause fuel rods to fail already at stresses below the yield strength. In the HFR, Petten, many power ramp experiments have been performed with subsequent examination of the ramped rods for fission product distribution. This study describes the measurement of iodine and cesium distribution using γ-spectroscopy of I-131 and Cs-137. An evaluation method is presented which makes the determination of absolute amounts of I/Cs feasible. It is shown that a threshold for I/Cs redistribution exists beyond which it depends strongly on local fuel rod power and fuel type.

Experimental investigation of a supersonic swept ramp injector using laser-induced iodine fluorescence

NASA Technical Reports Server (NTRS)

Hartfield, Roy J.; Hollo, Steven D.; Mcdaniel, James C.

1990-01-01

Planar measurements of injectant mole fraction and temperature have been conducted in a nonreacting supersonic combustor configured with underexpanded injection in the base of a swept ramp. The temperature measurements were conducted with a Mach 2 test section inlet in streamwise planes perpendicular to the test section wall on which the ramp was mounted. Injection concentration measurements, conducted in cross flow planes with both Mach 2 and Mach 2.9 free stream conditions, dramatically illustrate the domination of the mixing process by streamwise vorticity generated by the ramp. These measurements, conducted using a nonintrusive optical technique (laser-induced iodine fluorescence), provide an accurate and extensive experimental data base for the validation of computation fluid dynamic codes for the calculation of highly three-dimensional supersonic combustor flow fields.

Ramp-edge structured tunneling devices using ferromagnet electrodes

DOEpatents

Kwon, Chuhee [Long Beach, CA; Jia, Quanxi [Los Alamos, NM

2002-09-03

The fabrication of ferromagnet-insulator-ferromagnet magnetic tunneling junction devices using a ramp-edge geometry based on, e.g., (La.sub.0.7 Sr.sub.0.3) MnO.sub.3, ferromagnetic electrodes and a SrTiO.sub.3 insulator is disclosed. The maximum junction magnetoresistance (JMR) as large as 23% was observed below 300 Oe at low temperatures (T<100 K). These ramp-edge junctions exhibited JMR of 6% at 200 K with a field less than 100 Oe.

Using archived ITS data to measure the operational benefits of a system-wide adaptive ramp metering system : appendix online 10 : OR\\0x2010217 NB ramp flow & ML speed-flow plots.

DOT National Transportation Integrated Search

2008-12-01

The appendix includes various ramp flow and ML speed-flow plots: OR-217 NB, 72nd MP 6.61; OR-217 NB, 99W-EB MP 5.9; OR-217 NB, 99W-WB MP 5.85; OR-217 NB, Greenburg MP 4.65; OR-217 NB, Scholls MP 3.85; OR-217 NB, Denney MP 2.68; OR-217 NB, Allen MP 2....

Mars pathfinder Rover egress deployable ramp assembly

NASA Technical Reports Server (NTRS)

Spence, Brian R.; Sword, Lee F.

1996-01-01

The Mars Pathfinder Program is a NASA Discovery Mission, led by the Jet Propulsion Laboratory, to launch and place a small planetary Rover for exploration on the Martian surface. To enable safe and successful egress of the Rover vehicle from the spacecraft, a pair of flight-qualified, deployable ramp assemblies have been developed. This paper focuses on the unique, lightweight deployable ramp assemblies. A brief mission overview and key design requirements are discussed. Design and development activities leading to qualification and flight systems are presented.

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

Milkov, Mihail M.

A comparator circuit suitable for use in a column-parallel single-slope analog-to-digital converter comprises a comparator, an input voltage sampling switch, a sampling capacitor arranged to store a voltage which varies with an input voltage when the sampling switch is closed, and a local ramp buffer arranged to buffer a global voltage ramp applied at an input. The comparator circuit is arranged such that its output toggles when the buffered global voltage ramp exceeds the stored voltage. Both DC- and AC-coupled comparator embodiments are disclosed.

4. RAMP FOR BENJAMIN FRANKLIN BRIDGE (FOURTH ST.) BETWEEN VINE ...

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

4. RAMP FOR BENJAMIN FRANKLIN BRIDGE (FOURTH ST.) BETWEEN VINE AND RACE STS., LOOKING NORTHWEST - Independence National Historical Park, Walnut, Sixth, Chestnut & Second Streets, Philadelphia, Philadelphia County, PA

A machine learning calibration model using random forests to improve sensor performance for lower-cost air quality monitoring

NASA Astrophysics Data System (ADS)

Zimmerman, Naomi; Presto, Albert A.; Kumar, Sriniwasa P. N.; Gu, Jason; Hauryliuk, Aliaksei; Robinson, Ellis S.; Robinson, Allen L.; Subramanian, R.

2018-01-01

Low-cost sensing strategies hold the promise of denser air quality monitoring networks, which could significantly improve our understanding of personal air pollution exposure. Additionally, low-cost air quality sensors could be deployed to areas where limited monitoring exists. However, low-cost sensors are frequently sensitive to environmental conditions and pollutant cross-sensitivities, which have historically been poorly addressed by laboratory calibrations, limiting their utility for monitoring. In this study, we investigated different calibration models for the Real-time Affordable Multi-Pollutant (RAMP) sensor package, which measures CO, NO2, O3, and CO2. We explored three methods: (1) laboratory univariate linear regression, (2) empirical multiple linear regression, and (3) machine-learning-based calibration models using random forests (RF). Calibration models were developed for 16-19 RAMP monitors (varied by pollutant) using training and testing windows spanning August 2016 through February 2017 in Pittsburgh, PA, US. The random forest models matched (CO) or significantly outperformed (NO2, CO2, O3) the other calibration models, and their accuracy and precision were robust over time for testing windows of up to 16 weeks. Following calibration, average mean absolute error on the testing data set from the random forest models was 38 ppb for CO (14 % relative error), 10 ppm for CO2 (2 % relative error), 3.5 ppb for NO2 (29 % relative error), and 3.4 ppb for O3 (15 % relative error), and Pearson r versus the reference monitors exceeded 0.8 for most units. Model performance is explored in detail, including a quantification of model variable importance, accuracy across different concentration ranges, and performance in a range of monitoring contexts including the National Ambient Air Quality Standards (NAAQS) and the US EPA Air Sensors Guidebook recommendations of minimum data quality for personal exposure measurement. A key strength of the RF approach is that it accounts for pollutant cross-sensitivities. This highlights the importance of developing multipollutant sensor packages (as opposed to single-pollutant monitors); we determined this is especially critical for NO2 and CO2. The evaluation reveals that only the RF-calibrated sensors meet the US EPA Air Sensors Guidebook recommendations of minimum data quality for personal exposure measurement. We also demonstrate that the RF-model-calibrated sensors could detect differences in NO2 concentrations between a near-road site and a suburban site less than 1.5 km away. From this study, we conclude that combining RF models with carefully controlled state-of-the-art multipollutant sensor packages as in the RAMP monitors appears to be a very promising approach to address the poor performance that has plagued low-cost air quality sensors.

Recycling silicon wire-saw slurries: separation of silicon and silicon carbide in a ramp settling tank under an applied electrical field.

PubMed

Tsai, Tzu-Hsuan; Shih, Yu-Pei; Wu, Yung-Fu

2013-05-01

The growing demand for silicon solar cells in the global market has greatly increased the amount of silicon sawing waste produced each year. Recycling kerf Si and SiC from sawing waste is an economical method to reduce this waste. This study reports the separation of Si and SiC using a ramp settling tank. As they settle in an electrical field, small Si particles with higher negative charges have a longer horizontal displacement than SiC particles in a solution of pH 7, resulting in the separation of Si and SiC. The agreement between experimental results and predicted results shows that the particles traveled a short distance to reach the collection port in the ramp tank. Consequently, the time required for tiny particles to hit the tank bottom decreased, and the interference caused by the dispersion between particles and the fluid motion during settling decreased. In the ramp tank, the highest purities of the collected SiC and Si powders were 95.2 and 7.01 wt%, respectively. Using a ramp tank, the recycling fraction of Si-rich powders (SiC < 15 wt%) reached 22.67% (based on the whole waste). This fraction is greater than that achieved using rectangular tanks. Recycling Si and SiC abrasives from the silicon sawing waste is regarded as an economical solution to reduce the sawing waste. However, the separation of Si and SiC is difficult. This study reports the separation of Si and SiC using a ramp settling tank under an applied electrical field. As they settle in an electrical field, small Si particles with higher negative charges have a longer horizontal displacement than SiC particles in a solution of pH 7, resulting in the separation of Si and SiC. Compared with the rectangular tanks, the recycling fraction of Si-rich powders using a ramp tank is greater, and the proposed ramp settling tank is more suitable for industrial applications.

32. Underside of tracks showing columns, concreteencased Ibeams, and ramps ...

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

32. Underside of tracks showing columns, concrete-encased I-beams, and ramps near storage room. Looking southwest. - Stillwell Avenue Station, Intersection of Stillwell & Surf Avenues, Brooklyn, Kings County, NY

Comparison of Different Control Schemes for Strategic Departure Metering

NASA Technical Reports Server (NTRS)

Idris, Husni; Shen, Ni; Saraf, Aditya; Bertino, Jason; Zelinski, Shannon

2016-01-01

Airports and their terminal airspaces are key choke points in the air transportation system causing major delays and adding to pollution. A solution aimed at mitigating these chokepoints integrates the scheduling of runway operations, flight release from the gates and ramp into the airport movement area, and merging with other traffic competing for downstream airspace points. Within this integrated concept, we present a simulation-based analysis of the departure metering process, which delays the release of flights into the airport movement area while balancing two competing objectives: (1) maintaining large enough queues at the airport resources to maximize throughput and (2) absorbing excess delays at the gates or in ramp areas to save on fuel consumption, emissions, noise, and passenger discomfort. Three metering strategies are compared which respectively attempt to control the number of flights that (1) left the gate but did not take off, (2) left the ramp but did not take off, and (3) spent their unimpeded transit time to the runway but did not take off. It was observed that under deterministic and demand uncertainty conditions, the first strategy performed better than the other two strategies in terms of maintaining the runway throughput while transferring a significant average delay of two minutes to the gate. On the other hand, under uncertainties of flight transit time and runway service rate, all the strategies struggled to delay flights at the gate without a significant impact on the runway throughput.

Porous silicon based anode material formed using metal reduction

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

Anguchamy, Yogesh Kumar; Masarapu, Charan; Deng, Haixia

A porous silicon based material comprising porous crystalline elemental silicon formed by reducing silicon dioxide with a reducing metal in a heating process followed by acid etching is used to construct negative electrode used in lithium ion batteries. Gradual temperature heating ramp(s) with optional temperature steps can be used to perform the heating process. The porous silicon formed has a high surface area from about 10 m.sup.2/g to about 200 m.sup.2/g and is substantially free of carbon. The negative electrode formed can have a discharge specific capacity of at least 1800 mAh/g at rate of C/3 discharged from 1.5V tomore » 0.005V against lithium with in some embodiments loading levels ranging from about 1.4 mg/cm.sup.2 to about 3.5 mg/cm.sup.2. In some embodiments, the porous silicon can be coated with a carbon coating or blended with carbon nanofibers or other conductive carbon material.« less

STATUS OF VARIOUS SNS DIAGNOSTIC SYSTEMS

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

Blokland, Willem; Purcell, J David; Patton, Jeff

2007-01-01

The Spallation Neutron Source (SNS) accelerator systems are ramping up to deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. Enhancements or additions have been made to several instrument systems to support the ramp up in intensity, improve reliability, and/or add functionality. The Beam Current Monitors now support increased rep rates, the Harp system now includes charge density calculations for the target, and a new system has been created to collect data for the beam accounting and present the data over the web and to the operator consoles. The majority of themore » SNS beam instruments are PC-based and their configuration files are now managed through the Oracle relational database. A new version for the wire scanner software was developed to add features to correlate the scan with beam loss, parking in the beam, and measuring the longitudinal beam current. This software is currently being tested. This paper also includes data from the selected instruments.« less

`Relativistic' corrections to the mass of a plucked guitar string

NASA Astrophysics Data System (ADS)

Kolodrubetz, Michael; Polkovnikov, Anatoli

Quantum systems respond non-adiabaticity when parameters controlling them are ramped at a finite rate. If the parameters themselves are dynamical - for instance the position of a box that defines the boundary of a quantum field - the feedback of these excitations gives rise to effective Newtonian equations of motion for the parameter. For the age old problem of photons in a box, this correction gives rise to a mass proportional to the energy of the photons. We show that a similar correction arises for a classical guitar string plucked with energy E; moving clamps at the ends of the string requires inertial mass m = 2 E /cs2 , where cs is the speed of sound. This quasi-relativistic effect should be observable in freshman physics level experiments. We then comment on how these simple methods have been readily extended to treat problems such as ramps and quenches of strongly-interacting superconductors and dynamical trapping near a quantum critical point.

Dependence of Brownian and Néel relaxation times on magnetic field strength

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

Deissler, Robert J., E-mail: rjd42@case.edu; Wu, Yong; Martens, Michael A.

2014-01-15

Purpose: In magnetic particle imaging (MPI) and magnetic particle spectroscopy (MPS) the relaxation time of the magnetization in response to externally applied magnetic fields is determined by the Brownian and Néel relaxation mechanisms. Here the authors investigate the dependence of the relaxation times on the magnetic field strength and the implications for MPI and MPS. Methods: The Fokker–Planck equation with Brownian relaxation and the Fokker–Planck equation with Néel relaxation are solved numerically for a time-varying externally applied magnetic field, including a step-function, a sinusoidally varying, and a linearly ramped magnetic field. For magnetic fields that are applied as a stepmore » function, an eigenvalue approach is used to directly calculate both the Brownian and Néel relaxation times for a range of magnetic field strengths. For Néel relaxation, the eigenvalue calculations are compared to Brown's high-barrier approximation formula. Results: The relaxation times due to the Brownian or Néel mechanisms depend on the magnitude of the applied magnetic field. In particular, the Néel relaxation time is sensitive to the magnetic field strength, and varies by many orders of magnitude for nanoparticle properties and magnetic field strengths relevant for MPI and MPS. Therefore, the well-known zero-field relaxation times underestimate the actual relaxation times and, in particular, can underestimate the Néel relaxation time by many orders of magnitude. When only Néel relaxation is present—if the particles are embedded in a solid for instance—the authors found that there can be a strong magnetization response to a sinusoidal driving field, even if the period is much less than the zero-field relaxation time. For a ferrofluid in which both Brownian and Néel relaxation are present, only one relaxation mechanism may dominate depending on the magnetic field strength, the driving frequency (or ramp time), and the phase of the magnetization relative to the applied magnetic field. Conclusions: A simple treatment of Néel relaxation using the common zero-field relaxation time overestimates the relaxation time of the magnetization in situations relevant for MPI and MPS. For sinusoidally driven (or ramped) systems, whether or not a particular relaxation mechanism dominates or is even relevant depends on the magnetic field strength, the frequency (or ramp time), and the phase of the magnetization relative to the applied magnetic field.« less

Examination of B. subtilis var. niger Spore Killing by Dry Heat Methods

NASA Technical Reports Server (NTRS)

Kempf, Michael J.; Kirschner, Larry E.

2004-01-01

Dry heat microbial reduction is the only NASA approved sterilization method to reduce the microbial bioburden on space-flight hardware prior to launch. Reduction of the microbial bioburden on spacecraft is necessary to meet planetary protection requirements specific for the mission. Microbial bioburden reduction also occurs if a spacecraft enters a planetary atmosphere (e.g., Mars) and is heated due to frictional forces. Temperatures reached during atmospheric entry events (>200 C) are sufficient to damage or destroy flight hardware and also kill microbial spores that reside on the in-bound spacecraft. The goal of this research is to determine the survival rates of bacterial spores when they are subjected to conditions similar to those the spacecraft would encounter (i.e., temperature, pressure, etc.). B. subtilis var. niger spore coupons were exposed to a range of temperatures from 125 C to 200 C in a vacuum oven (at <1 Torr). After the exposures, the spores were removed by sonication, dilutions were made, and the spores were plated using the pour plate method with tryptic soy agar. After 3 days incubation at 32 C, the number of colony-forming units was counted. Lethality rate constants and D-values were calculated at each temperature. The calculated D-values were: 27 minutes (at 125 C), 13 minutes (at 135 C), and <0.1 minutes (at 150 C). The 125 C and 135 C survivor curves appeared as concavedownward curves. The 150 C survivor curve appeared as a straight-line. Due to the prolonged ramp-up time to the exposure conditions, spore killing during the ramp-up resulted in insufficient data to draw curves for exposures at 160 C, 175 C, and 200 C. Exploratory experiments using novel techniques, with short ramp times, for performing high temperature exposures were also examined. Several of these techniques, such as vacuum furnaces, thermal spore exposure vessels, and laser heating of the coupons, will be discussed.

Dissecting patterns of preparatory activity in the frontal eye fields during pursuit target selection.

PubMed

Raghavan, Ramanujan T; Joshua, Mati

2017-10-01

We investigated the composition of preparatory activity of frontal eye field (FEF) neurons in monkeys performing a pursuit target selection task. In response to the orthogonal motion of a large and a small reward target, monkeys initiated pursuit biased toward the direction of large reward target motion. FEF neurons exhibited robust preparatory activity preceding movement initiation in this task. Preparatory activity consisted of two components, ramping activity that was constant across target selection conditions, and a flat offset in firing rates that signaled the target selection condition. Ramping activity accounted for 50% of the variance in the preparatory activity and was linked most strongly, on a trial-by-trial basis, to pursuit eye movement latency rather than to its direction or gain. The offset in firing rates that discriminated target selection conditions accounted for 25% of the variance in the preparatory activity and was commensurate with a winner-take-all representation, signaling the direction of large reward target motion rather than a representation that matched the parameters of the upcoming movement. These offer new insights into the role that the frontal eye fields play in target selection and pursuit control. They show that preparatory activity in the FEF signals more strongly when to move rather than where or how to move and suggest that structures outside the FEF augment its contributions to the target selection process. NEW & NOTEWORTHY We used the smooth eye movement pursuit system to link between patterns of preparatory activity in the frontal eye fields and movement during a target selection task. The dominant pattern was a ramping signal that did not discriminate between selection conditions and was linked, on trial-by-trial basis, to movement latency. A weaker pattern was composed of a constant signal that discriminated between selection conditions but was only weakly linked to the movement parameters. Copyright © 2017 the American Physiological Society.

Stress evolution following the 1999 Chi-Chi, Taiwan, earthquake: Consequences for afterslip, relaxation, aftershocks and departures from Omori decay

USGS Publications Warehouse

Chan, C.-H.; Stein, R.S.

2009-01-01

We explore how Coulomb stress transfer and viscoelastic relaxation control afterslip and aftershocks in a continental thrust fault system. The 1999 September 21 Mw = 7.6 Chi-Chi shock is typical of continental ramp-d??collement systems throughout the world, and so inferences drawn from this uniquely well-recorded event may be widely applicable. First, we find that the spatial and depth distribution of aftershocks and their focal mechanisms are consistent with the calculated Coulomb stress changes imparted by the coseismic rupture. Some 61 per cent of the M ??? 2 aftershocks and 83 per cent of the M ??? 4 aftershocks lie in regions for which the Coulomb stress increased by ???0.1 bars, and there is a 11-12 per cent gain in the percentage of aftershocks nodal planes on which the shear stress increased over the pre-Chi Chi control period. Second, we find that afterslip occurred where the calculated coseismic stress increased on the fault ramp and d??collement, subject to the condition that friction is high on the ramp and low on the d??collement. Third, viscoelastic relaxation is evident from the fit of the post-seismic GPS data on the footwall. Fourth, we find that the rate of seismicity began to increase during the post-seismic period in an annulus extending east of the main rupture. The spatial extent of the seismicity annulus resembles the calculated ???0.05-bar Coulomb stress increase caused by viscoelastic relaxation and afterslip, and we find a 9-12 per cent gain in the percentage of focal mechanisms with >0.01-bar shear stress increases imparted by the post-seismic afterslip and relaxation in comparison to the control period. Thus, we argue that post-seismic stress changes can for the first time be shown to alter the production of aftershocks, as judged by their rate, spatial distribution, and focal mechanisms. ?? Journal compilation ?? 2009 RAS.

Staying Mobile

MedlinePlus

... representatives are factory-trained accessibility specialists in ramp design and installation and will provide a free evaluation and consultation to determine what ramp is best for your needs. Video Series Free From Falls Some MS symptoms and treatments ...

3. Cement and Plaster Warehouse, north facade. Loading ramp on ...

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

3. Cement and Plaster Warehouse, north facade. Loading ramp on the right. Utility building, intrusion, on the far right. - Curtis Wharf, Cement & Plaster Warehouse, O & Second Streets, Anacortes, Skagit County, WA

36 CFR 1192.101 - Lighting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Cars and Systems § 1192.101 Lighting. (a) Any stepwell or doorway with a lift, ramp or bridge plate..., ramp, bridge plate, or lift platform. (b) The doorways of cars not operating at lighted station...

36 CFR 1192.119 - Lighting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Cars and Systems § 1192.119 Lighting. (a) Any stepwell, or doorway with a lift, ramp or bridge plate..., ramp, bridge plate or lift platform. (b) The doorways of cars not operating at lighted station...

36 CFR 1192.119 - Lighting.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cars and Systems § 1192.119 Lighting. (a) Any stepwell, or doorway with a lift, ramp or bridge plate..., ramp, bridge plate or lift platform. (b) The doorways of cars not operating at lighted station...

36 CFR 1192.101 - Lighting.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cars and Systems § 1192.101 Lighting. (a) Any stepwell or doorway with a lift, ramp or bridge plate..., ramp, bridge plate, or lift platform. (b) The doorways of cars not operating at lighted station...

West view, general; Station Building, covered ramp, and Street Car ...

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

West view, general; Station Building, covered ramp, and Street Car Waiting House - North Philadelphia Station, 2900 North Broad Street, on northwest corner of Broad Street & Glenwood Avenue, Philadelphia, Philadelphia County, PA

Analysis Balance Parameter of Optimal Ramp metering

NASA Astrophysics Data System (ADS)

Li, Y.; Duan, N.; Yang, X.

2018-05-01

Ramp metering is a motorway control method to avoid onset congestion through limiting the access of ramp inflows into the main road of the motorway. The optimization model of ramp metering is developed based upon cell transmission model (CTM). With the piecewise linear structure of CTM, the corresponding motorway traffic optimization problem can be formulated as a linear programming (LP) problem. It is known that LP problem can be solved by established solution algorithms such as SIMPLEX or interior-point methods for the global optimal solution. The commercial software (CPLEX) is adopted in this study to solve the LP problem within reasonable computational time. The concept is illustrated through a case study of the United Kingdom M25 Motorway. The optimal solution provides useful insights and guidances on how to manage motorway traffic in order to maximize the corresponding efficiency.

Experimental studies on flow visualization and velocity field of compression ramp with different incoming boundary layers

NASA Astrophysics Data System (ADS)

Wu, Yu; Yi, Shi-He; He, Lin; Chen, Zhi; Zhu, Yang-Zhu

2014-11-01

Experimental studies which focus on flow visualization and the velocity field of a supersonic laminar/turbulent flow over a compression ramp were carried out in a Mach 3.0 wind tunnel. Fine flow structures and velocity field structures were obtained via NPLS (nanoparticle-tracer planar laser scattering) and PIV (particle image velocimetry) techniques, time-averaged flow structures were researched, and spatiotemporal evolutions of transient flow structures were analyzed. The flow visualization results indicated that when the ramp angles were 25°, a typical separation occurred in the laminar flow, some typical flow structures such as shock induced by the boundary layer, separation shock, reversed flow and reattachment shock were visible clearly. While a certain extent separation occurred in turbulent flow, the separation region was much smaller. When the ramp angles were 28°, laminar flow separated further, and the separation region expanded evidently, flow structures in the separation region were complex. While a typical separation occurred in turbulent flow, reversed flow structures were significant, flow structures in the separation region were relatively simple. The experimental results of velocity field were corresponding to flow visualization, and the velocity field structures of both compression ramp flows agreed with the flow structures well. There were three layered structures in the U component velocity, and the V component velocity appeared like an oblique “v”. Some differences between these two compression ramp flows can be observed in the velocity profiles of the shear layer and the shearing intensity.

Receptor Activity-modifying Protein-directed G Protein Signaling Specificity for the Calcitonin Gene-related Peptide Family of Receptors.

PubMed

Weston, Cathryn; Winfield, Ian; Harris, Matthew; Hodgson, Rose; Shah, Archna; Dowell, Simon J; Mobarec, Juan Carlos; Woodlock, David A; Reynolds, Christopher A; Poyner, David R; Watkins, Harriet A; Ladds, Graham

2016-10-14

The calcitonin gene-related peptide (CGRP) family of G protein-coupled receptors (GPCRs) is formed through the association of the calcitonin receptor-like receptor (CLR) and one of three receptor activity-modifying proteins (RAMPs). Binding of one of the three peptide ligands, CGRP, adrenomedullin (AM), and intermedin/adrenomedullin 2 (AM2), is well known to result in a Gα s -mediated increase in cAMP. Here we used modified yeast strains that couple receptor activation to cell growth, via chimeric yeast/Gα subunits, and HEK-293 cells to characterize the effect of different RAMP and ligand combinations on this pathway. We not only demonstrate functional couplings to both Gα s and Gα q but also identify a Gα i component to CLR signaling in both yeast and HEK-293 cells, which is absent in HEK-293S cells. We show that the CGRP family of receptors displays both ligand- and RAMP-dependent signaling bias among the Gα s , Gα i , and Gα q/11 pathways. The results are discussed in the context of RAMP interactions probed through molecular modeling and molecular dynamics simulations of the RAMP-GPCR-G protein complexes. This study further highlights the importance of RAMPs to CLR pharmacology and to bias in general, as well as identifying the importance of choosing an appropriate model system for the study of GPCR pharmacology. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Effect of thermal cycling ramp rate on CSP assembly reliability

NASA Technical Reports Server (NTRS)

Ghaffarian, R.

2001-01-01

A JPL-led chip scale package consortium of enterprises recently joined together to pool in-kind resources for developing the quality and reliability of chip scale packages for a variety of projects. The experience of the consortium in building more than 150 test vehicle assemblies, single and double sided multilayer PWBs, and the environmental test results has now been published as a chip scale package guidelines document.

Accelerated Strength Testing of Thermoplastic Composites

NASA Technical Reports Server (NTRS)

Reeder, J. R.; Allen, D. H.; Bradley, W. L.

1998-01-01

Constant ramp strength tests on unidirectional thermoplastic composite specimens oriented in the 90 deg. direction were conducted at constant temperatures ranging from 149 C to 232 C. Ramp rates spanning 5 orders of magnitude were tested so that failures occurred in the range from 0.5 sec. to 24 hrs. (0.5 to 100,000 MPa/sec). Below 204 C, time-temperature superposition held allowing strength at longer times to be estimated from strength tests at shorter times but higher temperatures. The data indicated that a 50% drop in strength might be expected for this material when the test time is increased by 9 orders of magnitude. The shift factors derived from compliance data applied well to the strength results. To explain the link between compliance and strength, a viscoelastic fracture model was investigated. The model, which used compliance as input, was found to fit the strength data only if the critical fracture energy was allowed to vary with temperature reduced stress rate. This variation in the critical parameter severely limits its use in developing a robust time-dependent strength model. The significance of this research is therefore seen as providing both the indication that a more versatile acceleration method for strength can be developed and the evidence that such a method is needed.

Probabilistic Wind Power Ramp Forecasting Based on a Scenario Generation Method

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

Wang, Qin; Florita, Anthony R; Krishnan, Venkat K

Wind power ramps (WPRs) are particularly important in the management and dispatch of wind power and currently drawing the attention of balancing authorities. With the aim to reduce the impact of WPRs for power system operations, this paper develops a probabilistic ramp forecasting method based on a large number of simulated scenarios. An ensemble machine learning technique is first adopted to forecast the basic wind power forecasting scenario and calculate the historical forecasting errors. A continuous Gaussian mixture model (GMM) is used to fit the probability distribution function (PDF) of forecasting errors. The cumulative distribution function (CDF) is analytically deduced.more » The inverse transform method based on Monte Carlo sampling and the CDF is used to generate a massive number of forecasting error scenarios. An optimized swinging door algorithm is adopted to extract all the WPRs from the complete set of wind power forecasting scenarios. The probabilistic forecasting results of ramp duration and start-time are generated based on all scenarios. Numerical simulations on publicly available wind power data show that within a predefined tolerance level, the developed probabilistic wind power ramp forecasting method is able to predict WPRs with a high level of sharpness and accuracy.« less

Ramp compression of a metallic liner driven by a shaped 5 MA current on the SPHINX machine

NASA Astrophysics Data System (ADS)

D'Almeida, Thierry; Lassalle, Francis; Morell, Alain; Grunenwald, Julien; Zucchini, Frédéric; Loyen, Arnaud; Maysonnave, Thomas; Chuvatin, Alexandre

2013-06-01

SPHINX is a 6MA, 1- μs Linear Transformer Driver operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. Among the options that are currently being considered for improving the generator performances, there is a compact Dynamic Load Current Amplifier (DLCM). A method for performing magnetic ramp compression experiments, without modifying the generator operation scheme, was developed using the DLCM to shape the initial current pulse. We present the overall experimental configuration chosen for these experiments, based on electrical and hydrodynamic simulations. Initial results obtained over a set of experiments on an aluminum cylindrical liner, ramp-compressed to a peak pressure of 23 GPa, are presented. Details of the electrical and Photonic Doppler Velocimetry (PDV) setups used to monitor and diagnose the ramp compression experiments are provided. Current profiles measured at various locations across the system, particularly the load current, agree with simulated current profile and demonstrate adequate pulse shaping by the DLCM. The liner inner free surface velocity measurements agree with the hydrocode results obtained using the measured load current as the input. Higher ramp pressure levels are foreseen in future experiments with an improved DLCM system.

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

Zhang, Jie; Cui, Mingjian; Hodge, Bri-Mathias

The large variability and uncertainty in wind power generation present a concern to power system operators, especially given the increasing amounts of wind power being integrated into the electric power system. Large ramps, one of the biggest concerns, can significantly influence system economics and reliability. The Wind Forecast Improvement Project (WFIP) was to improve the accuracy of forecasts and to evaluate the economic benefits of these improvements to grid operators. This paper evaluates the ramp forecasting accuracy gained by improving the performance of short-term wind power forecasting. This study focuses on the WFIP southern study region, which encompasses most ofmore » the Electric Reliability Council of Texas (ERCOT) territory, to compare the experimental WFIP forecasts to the existing short-term wind power forecasts (used at ERCOT) at multiple spatial and temporal scales. The study employs four significant wind power ramping definitions according to the power change magnitude, direction, and duration. The optimized swinging door algorithm is adopted to extract ramp events from actual and forecasted wind power time series. The results show that the experimental WFIP forecasts improve the accuracy of the wind power ramp forecasting. This improvement can result in substantial costs savings and power system reliability enhancements.« less

Evaluation of Pushback Decision-Support Tool Concept for Charlotte Douglas International Airport Ramp Operations

NASA Technical Reports Server (NTRS)

Hayashi, Miwa; Hoang, Ty; Jung, Yoon C.; Malik, Waqar; Lee, Hanbong; Dulchinos, Victoria L.

2015-01-01

This paper proposes a new departure pushback decision-support tool (DST) for airport ramp-tower controllers. It is based on NASA's Spot and Runway Departure Advisor (SARDA) collaborative decision-making concept, except with the modification that the gate releases now are controlled by tactical pushback (or gate-hold) advisories instead of strategic pre-assignments of target pushback times to individual departure flights. The proposed ramp DST relies on data exchange with the airport traffic control tower (ATCT) to coordinate pushbacks with the ATCT's flow-management intentions under current operational constraints, such as Traffic Management Initiative constraints. Airlines would benefit in reduced taxi delay and fuel burn. The concept was evaluated in a human-in-the-loop simulation experiment with current ramp-tower controllers at the Charlotte Douglas International Airport as participants. The results showed that the tool helped reduce taxi time by one minute per flight and overall departure flight fuel consumption by 10-12% without reducing runway throughput. Expect Departure Clearance Time (EDCT) conformance also was improved when advisories were provided. These benefits were attained without increasing the ramp-tower controllers' workload. Additionally, the advisories reduced the ATCT controllers' workload.

Probabilistic Wind Power Ramp Forecasting Based on a Scenario Generation Method: Preprint

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

Wang, Qin; Florita, Anthony R; Krishnan, Venkat K

2017-08-31

Wind power ramps (WPRs) are particularly important in the management and dispatch of wind power, and they are currently drawing the attention of balancing authorities. With the aim to reduce the impact of WPRs for power system operations, this paper develops a probabilistic ramp forecasting method based on a large number of simulated scenarios. An ensemble machine learning technique is first adopted to forecast the basic wind power forecasting scenario and calculate the historical forecasting errors. A continuous Gaussian mixture model (GMM) is used to fit the probability distribution function (PDF) of forecasting errors. The cumulative distribution function (CDF) ismore » analytically deduced. The inverse transform method based on Monte Carlo sampling and the CDF is used to generate a massive number of forecasting error scenarios. An optimized swinging door algorithm is adopted to extract all the WPRs from the complete set of wind power forecasting scenarios. The probabilistic forecasting results of ramp duration and start time are generated based on all scenarios. Numerical simulations on publicly available wind power data show that within a predefined tolerance level, the developed probabilistic wind power ramp forecasting method is able to predict WPRs with a high level of sharpness and accuracy.« less

Self-focusing and defocusing of Gaussian laser beams in collisional inhomogeneous plasmas with linear density and temperature ramps

NASA Astrophysics Data System (ADS)

Hashemzadeh, M.

2018-01-01

Self-focusing and defocusing of Gaussian laser beams in collisional inhomogeneous plasmas are investigated in the presence of various laser intensities and linear density and temperature ramps. Considering the ponderomotive force and using the momentum transfer and energy equations, the nonlinear electron density is derived. Taking into account the paraxial approximation and nonlinear electron density, a nonlinear differential equation, governing the focusing and defocusing of the laser beam, is obtained. Results show that in the absence of ramps the laser beam is focused between a minimum and a maximum value of laser intensity. For a certain value of laser intensity and initial electron density, the self-focusing process occurs in a temperature range which reaches its maximum at turning point temperature. However, the laser beam is converged in a narrow range for various amounts of initial electron density. It is indicated that the σ2 parameter and its sign can affect the self-focusing process for different values of laser intensity, initial temperature, and initial density. Finally, it is found that although the electron density ramp-down diverges the laser beam, electron density ramp-up improves the self-focusing process.

ALINEA local ramp metering : summary of field results

DOT National Transportation Integrated Search

1997-01-01

Asservissement Linaire dEntre Autoroutire (ALINEA), a local feedback ramp-metering strategy, has had multiple field applications, and more applications are planned in several European countries. The main features of ALINEA are presented and ...

Guidelines for spacing between freeway ramps.

DOT National Transportation Integrated Search

2009-11-01

Existing geometric design guidance related to interchange ramp spacing in the Texas Roadway Design : Manual and the AASHTOs A Policy on Geometric Design of Highways and Streets (Green Book) is not : speed-dependent even though intuition indicates ...

Highway Safety Manual applied in Missouri - freeway/software : research summary.

DOT National Transportation Integrated Search

2016-03-01

AASHTOs Highway Safety Manual (HSM) : includes models for freeway segments, speedchange : lanes (transitional area between mainline : and ramps), ramps, and interchange terminals. : These predictive models for freeway : interchanges need to be cal...

49 CFR 38.119 - Lighting.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., or doorway with a lift, ramp or bridge plate, shall have, when the door is open, at least 2 foot-candles of illumination measured on the step tread, ramp, bridge plate or lift platform. (b) The doorways...

49 CFR 38.119 - Lighting.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., or doorway with a lift, ramp or bridge plate, shall have, when the door is open, at least 2 foot-candles of illumination measured on the step tread, ramp, bridge plate or lift platform. (b) The doorways...

49 CFR 38.101 - Lighting.

Code of Federal Regulations, 2011 CFR

2011-10-01

... doorway with a lift, ramp or bridge plate shall have, when the door is open, at least 2 footcandles of illumination measured on the step tread, ramp, bridge plate, or lift platform. (b) The doorways of cars not...

49 CFR 38.101 - Lighting.

Code of Federal Regulations, 2010 CFR

2010-10-01

... doorway with a lift, ramp or bridge plate shall have, when the door is open, at least 2 footcandles of illumination measured on the step tread, ramp, bridge plate, or lift platform. (b) The doorways of cars not...

30. Underside of tracks showing columns, concreteencased Ibeams, and ramps ...

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

30. Underside of tracks showing columns, concrete-encased I-beams, and ramps near token booths at street level. Looking southeast. - Stillwell Avenue Station, Intersection of Stillwell & Surf Avenues, Brooklyn, Kings County, NY

WALK UP RAMP - ASTRONAUT THOMAS P. STAFFORD - MISC.

NASA Image and Video Library

1966-06-03

S66-32149 (3 June 1966) --- Astronauts Thomas P. Stafford (foreground), command pilot, and Eugene A. Cernan, pilot, walk up the ramp at Pad 19 during the Gemini-9A prelaunch countdown. Photo credit: NASA

North rear, east part. Ramp leads to basement utility rooms ...

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

North rear, east part. Ramp leads to basement utility rooms and specimen preparation rooms. - San Bernardino Valley College, Life Science Building, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

On Asymptotically Good Ramp Secret Sharing Schemes

NASA Astrophysics Data System (ADS)

Geil, Olav; Martin, Stefano; Martínez-Peñas, Umberto; Matsumoto, Ryutaroh; Ruano, Diego

Asymptotically good sequences of linear ramp secret sharing schemes have been intensively studied by Cramer et al. in terms of sequences of pairs of nested algebraic geometric codes. In those works the focus is on full privacy and full reconstruction. In this paper we analyze additional parameters describing the asymptotic behavior of partial information leakage and possibly also partial reconstruction giving a more complete picture of the access structure for sequences of linear ramp secret sharing schemes. Our study involves a detailed treatment of the (relative) generalized Hamming weights of the considered codes.

Programmable Multiple-Ramped-Voltage Power Supply

NASA Technical Reports Server (NTRS)

Ajello, Joseph M.; Howell, S. K.

1993-01-01

Ramp waveforms range up to 2,000 V. Laboratory high-voltage power-supply system puts out variety of stable voltages programmed to remain fixed with respect to ground or float with respect to ramp waveform. Measures voltages it produces with high resolution; automatically calibrates, zeroes, and configures itself; and produces variety of input/output signals for use with other instruments. Developed for use with ultraviolet spectrometer. Also applicable to control of electron guns in general and to operation of such diverse equipment used in measuring scattering cross sections of subatomic particles and in industrial electron-beam welders.

Coarse cross-bedded grainstones in a mid- to outer carbonate ramp, Bartonian of the Urbasa-Andia plateau (W Pyrenees, N Spain)

NASA Astrophysics Data System (ADS)

Baceta, José I.; Pomar, Luis; Mateu-Vicens, Guillem

2017-04-01

Most marine grainstones in carbonate ramps and platforms are commonly interpreted to form in high-energy, shallow-water settings where wave energy dissipates by friction on the sea floor. The locus of energy dissipation varies with platform type. On rimmed shelves, skeletal-oolitic sands mainly accumulate near the wave-agitated shelf margin as a rim, which restricts wave action and a low-energy lagoon may form landwards. On ramps and open platforms, by contrast, grainstones commonly accumulate in the shallower zone near or attached to the shoreline, grading basinward into muddier carbonate successions. Within this conceptual scheme, most carbonate ramp subdivisions have been established according to the facies and sedimentary structures associated to the bathymetry-related hydraulic regime, in which the bases of the surface storm-waves and the fairweather waves are the boundary layers. Since seagrasses encroached the oceans by the late Cretaceous, baffling the surface wave energy, and burrowing activity increased significantly, most Cenozoic ramp successions lack the bathymetry-related sedimentary structures and the record of wave and storm activity is commonly lost. This has induced ramp subdivision to become progressively based in light penetration, as inferred from the light dependence of the carbonate producers, particularly for the Cenozoic. This new scenario has permitted to recognize grainstone units detached from shoreline and shoals and produced at depths near the limit of light penetration, or even below, in basinal settings. Here we document a 90-100-m thick Eocene example of crossbedded skeletal grainstones composed by echinoderm-, bryozoan-, red-algal fragments and orthophragminid larger benthic foraminifers. This facies belt occurs at 20-km from the paleo-coastline, downdip of Nummulites-Discocyclina facies, and passes basinward into finely comminuted skeletal debris and marls with planktonic foraminifers of the outer ramp. The skeletal composition of the cross-bedded belt indicates carbonate production to have occurred near the lower limit of the light penetration, and hydraulic turbulence to rework the coarser sediments and winnow-away de fines at the transition between middle- and outer ramp. Bedform migration indicates two main flow directions: oblique upslope traction currents (run-up) and downslope backwash return flow. This indicates turbulence to be detached from the surface storm waves and suggests internal waves breaking obliquely to the slopping ramp. This example documents the potential role of internal waves in shaping and redistributing sediments across ancient carbonate ramp systems, producing porous bodies close to basinal facies. These grainstone bodies may become good targets but acquire special relevance when prediction of good drains is needed in both exploration and production of unconventional. ACKNOWLEDGEMENTS Funding from Ministerio de Economía y Competitividad Project CGL2014-52096-P is acknowledged. This is also a contribution to the Research Group of the Basque University System IT-930-16.

Changes of hydrodynamic parameters on mountain stream bed within the block ramp influence and possibility of their use for integrated river management

NASA Astrophysics Data System (ADS)

Radecki-Pawlik, Artur; Plesiński, Karol

2016-04-01

In modern river management practices and philosophy one can notice coming more into use ecological friendly hydraulic structures. Those, which are especially needed for river training works, as far as expectation of Water Framework Directive is concerned, are block ramps which are hydraulic structures working similar to riffles known very well from fluvial geomorphology studies and are natural features in streams and rivers. What is important well designed block ramps do not stop fish and invertebrates against migrating, provide natural and esthetical view being built within the river channel, still working as hydraulic engineering structures and might be used in river management in different river ecosystems. The main aim of the research was to describe changes of values of hydrodynamics parameters upstream and downstream of the block ramps and to find out their influence on hydrodynamics of the stream. The study was undertaken on the Porębianka River in the Gorce Mountains, Polish Carpathians. Observed hydrodynamic parameters within the reach of the block ramps depend on the location of measuring point and the influence of individual part of the structure. We concluded that: 1. Hydrodynamic parameters close to block ramps depend on the location of the measurement points in relation to particular elements of the structure; 2. The highest value of velocities don't cause the highest force values, which acting on the bed of the watercourse, because they are rather related to the water level of the channel; 3. The values of mean velocities, shear velocities and shear stresses were similar upstream and downstream the block ramps, which means that the structures stabilize the river bed. This study was performed within the scope of the Science Activity money from Ministry of High Education and Young Scientist's Activity Money of Department of Hydraulics Engineering and Geotechnique, University of Agriculture, Cracow, Poland

Lifestyles of the palaeoproterozoic stromatolite builders in the Vempalle Sea, Cuddapah Basin, India

NASA Astrophysics Data System (ADS)

Patranabis-Deb, Sarbani; Majumder, Tuasha; Khan, Sayani

2018-05-01

The distribution and changing pattern of stromatolites in the Vempalle Formation of the Cuddapah Basin, India, have been investigated with emphasis on external morphologies, internal fabrics, growth patterns and sediment associations. The stromatolitic limestone occurs in a low angle ramp type carbonate platform, with complete exposures from shallow shelf to basinal facies, provides record of changes in reef-building capacity of stromatolites with change in the depositional milieu. Changing pattern and style of the stromatolites clearly reflect depth partitioned growth of the microbial community. Small and scattered stromatolites, commonly with wavy parallel laminations or stratifications occurred in inner-ramp settings, where they are build up to the sea level. Tepee structure and desiccation cracks in associated sediments and salt pseudomorphs point to shallow water to occasional exposure condition. Large bioherms with columnar and conical stromatolites developed in the headland (mid ramp), which were in continuous interaction with strong waves of the open sea. Growth of the bioherms changed the landform with time and generated a high sloping edge with a sheer drop that extended out into the sea, forming distally steepened ramp. Outer ramp lithofacies characterized by thick layers of shale succession with thin beds of laterally persistent stromatolitic beds with low synoptic relief build-ups. These biotic components, along with the absence of wave-related structures, place the outer ramp below the base of wave action zone. Ooid banks developed in the mid ramp area are in the high surfing zone. High flux of nutrients and high-light show positive correlation; thus the high growth pattern is best observed within the photic zone where wave action is maximum. The ability to change from low synoptic relief algal laminites to high synoptic relief columnar stromatolites point to their adaptive power. The key factor that controlled the shape of these Palaeoproterozoic stromatolites is the dynamic interactions between mat growth, currents and sediment supply. Presence of concentric and radial fibrous ooids indicates change in climate and salinity of the sea.

Validating the energy transport modeling of the DIII-D and EAST ramp up experiments using TSC

NASA Astrophysics Data System (ADS)

Liu, Li; Guo, Yong; Chan, Vincent; Mao, Shifeng; Wang, Yifeng; Pan, Chengkang; Luo, Zhengping; Zhao, Hailin; Ye, Minyou

2017-06-01

The confidence in ramp up scenario design of the China fusion engineering test reactor (CFETR) can be significantly enhanced using validated transport models to predict the current profile and temperature profile. In the tokamak simulation code (TSC), two semi-empirical energy transport models (the Coppi-Tang (CT) and BGB model) and three theory-based models (the GLF23, MMM95 and CDBM model) are investigated on the CFETR relevant ramp up discharges, including three DIII-D ITER-like ramp up discharges and one EAST ohmic discharge. For the DIII-D discharges, all the transport models yield dynamic {{\\ell}\\text{i}} within +/- 0.15 deviations except for some time points where the experimental fluctuation is very strong. All the models agree with the experimental {β\\text{p}} except that the CT model strongly overestimates {β\\text{p}} in the first half of ramp up phase. When applying the CT, CDBM and GLF23 model to estimate the internal flux, they show maximum deviations of more than 10% because of inaccuracies in the temperature profile predictions, while the BGB model performs best on the internal flux. Although all the models fall short in reproducing the dynamic {{\\ell}\\text{i}} evolution for the EAST tokamak, the result of the BGB model is the closest to the experimental {{\\ell}\\text{i}} . Based on these comparisons, we conclude that the BGB model is the most consistent among these models for simulating CFETR ohmic ramp-up. The CT model with improvement for better simulation of the temperature profiles in the first half of ramp up phase will also be attractive. For the MMM95, GLF23 and CDBM model, better prediction of the edge temperature will improve the confidence for CFETR L-mode simulation. Conclusive validation of any transport model will require extensive future investigation covering a larger variety discharges.

Effects of the Multidisciplinary Risk Assessment and Management Program for Patients with Diabetes Mellitus (RAMP-DM) on biomedical outcomes, observed cardiovascular events and cardiovascular risks in primary care: a longitudinal comparative study.

PubMed

Jiao, Fang Fang; Fung, Colman Siu Cheung; Wong, Carlos King Ho; Wan, Yuk Fai; Dai, Daisy; Kwok, Ruby; Lam, Cindy Lo Kuen

2014-08-21

To assess whether the Multidisciplinary Risk Assessment and Management Program for Patients with Diabetes Mellitus (RAMP-DM) led to improvements in biomedical outcomes, observed cardiovascular events and predicted cardiovascular risks after 12-month intervention in the primary care setting. A random sample of 1,248 people with diabetes enrolled to RAMP-DM for at least 12 months was selected and 1,248 people with diabetes under the usual primary care were matched by age, sex, and HbA1c level at baseline as the usual care group. Biomedical and cardiovascular outcomes were measured at baseline and at 12-month after the enrollment. Difference-in-differences approach was employed to measure the effect of RAMP-DM on the changes in biomedical outcomes, proportion of subjects reaching treatment targets, observed and predicted cardiovascular risks. Compared to the usual care group, RAMP-DM group had lower cardiovascular events incidence (1.21% vs 2.89%, P = 0.003), and net decrease in HbA1c (-0.20%, P < 0.01), SBP (-3.62 mmHg, P < 0.01) and 10-year cardiovascular disease (CVD) risks (total CVD risk, -2.06%, P < 0.01; coronary heart disease (CHD) risk, -1.43%, P < 0.01; stroke risk, -0.71%, P < 0.01). The RAMP-DM subjects witnessed significant rises in the proportion of reaching treatment targets of HbA1c, and SBP/DBP. After adjusting for confounding variables, the significance remained for HbA1c, predicted CHD and stroke risks. The RAMP-DM resulted in greater improvements in HbA1c and reduction in observed and predicted cardiovascular risks at 12 months follow-up, which indicated a risk-stratification multidisciplinary intervention was an effective strategy for managing Chinese people with diabetes in the primary care setting. ClinicalTrials.gov, NCT02034695.

Climatological attribution of wind power ramp events in East Japan and their probabilistic forecast based on multi-model ensembles downscaled by analog ensemble using self-organizing maps

NASA Astrophysics Data System (ADS)

Ohba, Masamichi; Nohara, Daisuke; Kadokura, Shinji

2016-04-01

Severe storms or other extreme weather events can interrupt the spin of wind turbines in large scale that cause unexpected "wind ramp events". In this study, we present an application of self-organizing maps (SOMs) for climatological attribution of the wind ramp events and their probabilistic prediction. The SOM is an automatic data-mining clustering technique, which allows us to summarize a high-dimensional data space in terms of a set of reference vectors. The SOM is applied to analyze and connect the relationship between atmospheric patterns over Japan and wind power generation. SOM is employed on sea level pressure derived from the JRA55 reanalysis over the target area (Tohoku region in Japan), whereby a two-dimensional lattice of weather patterns (WPs) classified during the 1977-2013 period is obtained. To compare with the atmospheric data, the long-term wind power generation is reconstructed by using a high-resolution surface observation network AMeDAS (Automated Meteorological Data Acquisition System) in Japan. Our analysis extracts seven typical WPs, which are linked to frequent occurrences of wind ramp events. Probabilistic forecasts to wind power generation and ramps are conducted by using the obtained SOM. The probability are derived from the multiple SOM lattices based on the matching of output from TIGGE multi-model global forecast to the WPs on the lattices. Since this method effectively takes care of the empirical uncertainties from the historical data, wind power generation and ramp is probabilistically forecasted from the forecasts of global models. The predictability skill of the forecasts for the wind power generation and ramp events show the relatively good skill score under the downscaling technique. It is expected that the results of this study provides better guidance to the user community and contribute to future development of system operation model for the transmission grid operator.

An active one-particle microrheometer: incorporating magnetic tweezers to total internal reflection microscopy.

PubMed

Gong, Xiangjun; Hua, Li; Wu, Chi; Ngai, To

2013-03-01

We present a novel microrheometer by incorporating magnetic tweezers in the total internal reflection microscopy (TIRM) that enables measuring of viscoelastic properties of materials near solid surface. An evanescent wave generated by a solid∕liquid interface in the TIRM is used as the incident light source in the microrheometer. When a probe particle (of a few micrometers diameter) moves near the interface, it can interact with the evanescent field and reflect its position with respect to the interface by the scattered light intensity. The exponential distance dependence of the evanescent field, on the one hand, makes this technique extremely sensitive to small changes from z-fluctuations of the probe (with a resolution of several nanometers), and on the other, it does not require imaging of the probe with high lateral resolution. Another distinct advantage is the high sensitivity in determining the z position of the probe in the absence of any labeling. The incorporated magnetic tweezers enable us to effectively manipulate the distance of the embedded particle from the interface either by a constant or an oscillatory force. The force ramp is easy to implement through a coil current ramp. In this way, the local viscous and elastic properties of a given system under different confinements can therefore be measured by resolving the near-surface particle motion. To test the feasibility of applying this microrheology to soft materials, we measured the viscoelastic properties of sucrose and poly(ethylene glycol) solutions and compared the results to bulk rheometry. In addition, we applied this technique in monitoring the structure and properties of deformable microgel particles near the flat surface.

Asymmetric flow field flow fractionation with light scattering detection - an orthogonal sensitivity analysis.

PubMed

Galyean, Anne A; Filliben, James J; Holbrook, R David; Vreeland, Wyatt N; Weinberg, Howard S

2016-11-18

Asymmetric flow field flow fractionation (AF 4 ) has several instrumental factors that may have a direct effect on separation performance. A sensitivity analysis was applied to ascertain the relative importance of AF 4 primary instrument factor settings for the separation of a complex environmental sample. The analysis evaluated the impact of instrumental factors namely, cross flow, ramp time, focus flow, injection volume, and run buffer concentration on the multi-angle light scattering measurement of natural organic matter (NOM) molar mass (MM). A 2 (5-1) orthogonal fractional factorial design was used to minimize analysis time while preserving the accuracy and robustness in the determination of the main effects and interactions between any two instrumental factors. By assuming that separations resulting in smaller MM measurements would be more accurate, the analysis produced a ranked list of effects estimates for factors and interactions of factors based on their relative importance in minimizing the MM. The most important and statistically significant AF 4 instrumental factors were buffer concentration and cross flow. The least important was ramp time. A parallel 2 (5-2) orthogonal fractional factorial design was also employed on five environmental factors for synthetic natural water samples containing silver nanoparticles (NPs), namely: NP concentration, NP size, NOM concentration, specific conductance, and pH. None of the water quality characteristic effects or interactions were found to be significant in minimizing the measured MM; however, the interaction between NP concentration and NP size was an important effect when considering NOM recovery. This work presents a structured approach for the rigorous assessment of AF 4 instrument factors and optimal settings for the separation of complex samples utilizing efficient orthogonal factional factorial design and appropriate graphical analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Design and scope of impact of auxiliary lanes : technical report.

DOT National Transportation Integrated Search

2014-06-01

For decades, Texas Department of Transportation districts have constructed auxiliary lanes to support interchange : ramp operations and to resolve congestion proximate to freeway entrance and exit ramps. While auxiliary lanes are : built throughout T...

4. Threequarter view of Asylum (Western) Avenue viaduct and ramp ...

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

4. Three-quarter view of Asylum (Western) Avenue viaduct and ramp on southeast corner of bridge, facing northwest. - Asylum Avenue Viaduct, Spanning Second Creek & Southern Railroad at State Route 62, Knoxville, Knox County, TN

15. FIGUEROA STREET NORTHBOUND EXIT RAMP UNDER SOUTHBOUND LANES. UPPER ...

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

15. FIGUEROA STREET NORTHBOUND EXIT RAMP UNDER SOUTHBOUND LANES. UPPER LEVEL IS INTERSTATE 1-5. LOOKING 162° SSE. - Arroyo Seco Parkway, Figueroa Street Viaduct, Spanning Los Angeles River, Los Angeles, Los Angeles County, CA

X-36 on Ramp Viewed from Above

NASA Image and Video Library

1997-07-16

This look-down view of the X-36 Tailless Fighter Agility Research Aircraft on the ramp at NASA’s Dryden Flight Research Center, Edwards, California, clearly shows the unusual wing and canard design of the remotely-piloted aircraft.

South view; Interior view of covered ramp to Street Car ...

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

South view; Interior view of covered ramp to Street Car Waiting House from Station Building - North Philadelphia Station, 2900 North Broad Street, on northwest corner of Broad Street & Glenwood Avenue, Philadelphia, Philadelphia County, PA

North view; Interior view of covered ramp to Station Building ...

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

North view; Interior view of covered ramp to Station Building from Street Car Waiting House - North Philadelphia Station, 2900 North Broad Street, on northwest corner of Broad Street & Glenwood Avenue, Philadelphia, Philadelphia County, PA

West view, general; Station Building, covered ramp, and Street Car ...

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

West view, general; Station Building, covered ramp, and Street Car Waiting House, right to left - North Philadelphia Station, 2900 North Broad Street, on northwest corner of Broad Street & Glenwood Avenue, Philadelphia, Philadelphia County, PA

An Evaluation of detectable warning surfaces for sidewalk curb ramps.

DOT National Transportation Integrated Search

1995-01-01

The 1991 Americans with Disabilities Act Accessibility Guidelines required the installation of a detectable warning surface (raised truncated domes) on sidewalk curb ramps to alert visually impaired people to potential hazards. Although this requirem...

Facility S 372, replacement dolphins and ramp from upper deck ...

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

Facility S 372, replacement dolphins and ramp from upper deck of ferry boat (YFB 87). - U.S. Naval Base, Pearl Harbor, Ferry Landing Type, Halawa Landing on Ford Island, Pearl City, Honolulu County, HI

Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples.

PubMed

Gerace, E; Salomone, A; Abbadessa, G; Racca, S; Vincenti, M

2012-02-01

A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone) plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid-liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS) after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration.

Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples

PubMed Central

Gerace, E.; Salomone, A.; Abbadessa, G.; Racca, S.; Vincenti, M.

2011-01-01

A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone) plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid–liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS) after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration. PMID:29403714

Dynamics of the outgoing turbulent boundary layer in a Mach 5 unswept compression ramp interaction

NASA Technical Reports Server (NTRS)

Gramann, Richard A.; Dolling, David S.

1990-01-01

Wall pressure fluctuations have been measured under the unsteady separation shock and on the ramp face in an unswept Mach 5 compression ramp interaction. The freestream Reynolds number was 51.0 x 10 to the 6th/m, and the incoming turbulent boundary layer developed on the tunnel floor under approximately adiabatic wall temperature conditions. Standard data-acquisition methods, as well as real-time and posttest conditional sampling techniques were used. The results show that the mean and rms pressure levels are strong functions of separation shock position. At all stations on the ramp, from the corner to where the pressure reaches the theoretical inviscid value, the pressure signals have two dominant components: a low frequency component characteristic of the global unsteadiness, which correlates with the separation shock motion, and a higher frequency component associated with turbulence. The former is the major contributor to the overall signal variance.

Interactive computer graphics applications for compressible aerodynamics

NASA Technical Reports Server (NTRS)

Benson, Thomas J.

1994-01-01

Three computer applications have been developed to solve inviscid compressible fluids problems using interactive computer graphics. The first application is a compressible flow calculator which solves for isentropic flow, normal shocks, and oblique shocks or centered expansions produced by two dimensional ramps. The second application couples the solutions generated by the first application to a more graphical presentation of the results to produce a desk top simulator of three compressible flow problems: 1) flow past a single compression ramp; 2) flow past two ramps in series; and 3) flow past two opposed ramps. The third application extends the results of the second to produce a design tool which solves for the flow through supersonic external or mixed compression inlets. The applications were originally developed to run on SGI or IBM workstations running GL graphics. They are currently being extended to solve additional types of flow problems and modified to operate on any X-based workstation.

Micro-Ramp Flow Control for Oblique Shock Interactions: Comparisons of Computational and Experimental Data

NASA Technical Reports Server (NTRS)

Hirt, Stephanie M.; Reich, David B.; O'Connor, Michael B.

2012-01-01

Computational fluid dynamics was used to study the effectiveness of micro-ramp vortex generators to control oblique shock boundary layer interactions. Simulations were based on experiments previously conducted in the 15- by 15-cm supersonic wind tunnel at the NASA Glenn Research Center. Four micro-ramp geometries were tested at Mach 2.0 varying the height, chord length, and spanwise spacing between micro-ramps. The overall flow field was examined. Additionally, key parameters such as boundary-layer displacement thickness, momentum thickness and incompressible shape factor were also examined. The computational results predicted the effects of the microramps well, including the trends for the impact that the devices had on the shock boundary layer interaction. However, computing the shock boundary layer interaction itself proved to be problematic since the calculations predicted more pronounced adverse effects on the boundary layer due to the shock than were seen in the experiment.

Three-dimensional supersonic flow around double compression ramp with finite span

NASA Astrophysics Data System (ADS)

Lee, H. S.; Lee, J. H.; Park, G.; Park, S. H.; Byun, Y. H.

2017-01-01

Three-dimensional flows of Mach number 3 around a double-compression ramp with finite span have been investigated numerically. Shadowgraph visualisation images obtained in a supersonic wind tunnel are used for comparison. A three-dimensional Reynolds-averaged Navier-Stokes solver was used to obtain steady numerical solutions. Two-dimensional numerical results are also compared. Four different cases were studied: two different second ramp angles of 30° and 45° in configurations with and without sidewalls, respectively. Results showed that there is a leakage of mass and momentum fluxes heading outwards in the spanwise direction for three-dimensional cases without sidewalls. The leakage changed the flow characteristics of the shock-induced boundary layer and resulted in the discrepancy between the experimental data and two-dimensional numerical results. It is found that suppressing the flow leakage by attaching the sidewalls enhances the two-dimensionality of the experimental data for the double-compression ramp flow.

Fault-controlled pluton emplacement in the Sevier fold-and-thrust belt of southwest Montana, USA

NASA Astrophysics Data System (ADS)

Kalakay, Thomas J.; John, Barbara E.; Lageson, David R.

2001-06-01

Problems associated with syncompressional pluton emplacement center on the need to make room for magma in environments where crustal shortening, not extension, occurs on a regional scale. New structural data from the Pioneer and Boulder batholiths of southwest Montana, USA, suggest emplacement at the top of frontal thrust ramps as composite tabular bodies at crustal depths between 1 and 10 km. Frontal thrust facilitated pluton emplacement was accommodated by: (1) a magma feeder zone created along the ramp interface; (2) providing 'releasing steps' at ramp tops that serve as initial points of emplacement and subsequent pluton growth; and (3) localizing antithetic back-thrusts that assist in pluton ascent. A model of magma emplacement is proposed that involves these elements. This model for syntectonic ramp-top emplacement of plutons helps explain how space is made for plutons within fold-and-thrust belts.

Spin-Flipping Polarized Deuterons At COSY

NASA Astrophysics Data System (ADS)

Yonehara, K.; Krisch, A. D.; Morozov, V. S.; Raymond, R. S.; Wong, V. K.; Bechstedt, U.; Gebel, R.; Lehrach, A.; Lorenz, B.; Maier, R.; Prasuhn, D.; Schnase, A.; Stockhorst, H.; Eversheim, D.; Hinterberger, F.; Rohdjess, H.; Ulbrich, K.; Scobel, W.

2004-02-01

We recently stored a 1.85 GeV/c vertically polarized deuteron beam in the COSY Ring in Jülich; we then spin-flipped it by ramping a new air-core rf dipole's frequency through an rf-induced spin resonance to manipulate the polarization direction of the deuteron beam. We first experimentally determined the resonance's frequency and set the dipole's rf voltage to its maximum; then we varied its frequency ramp time and frequency range. We used the EDDA detector to measure the vector and tensor polarization asymmetries. We have not yet extracted the deuteron's tensor polarization spin-flip parameters from the measured data, since our short run did not provide adequate tensor analyzing-power data at 1.85 GeV/c. However, with a 100 Hz frequency ramp and our longest ramp time of 400 s, the deuterons' vector polarization spin-flip efficiency was 48±1%.

Simulation of profile evolution from ramp-up to ramp-down and optimization of tokamak plasma termination with the RAPTOR code

NASA Astrophysics Data System (ADS)

Teplukhina, A. A.; Sauter, O.; Felici, F.; Merle, A.; Kim, D.; the TCV Team; the ASDEX Upgrade Team; the EUROfusion MST1 Team

2017-12-01

The present work demonstrates the capabilities of the transport code RAPTOR as a fast and reliable simulator of plasma profiles for the entire plasma discharge, i.e. from ramp-up to ramp-down. This code focuses, at this stage, on the simulation of electron temperature and poloidal flux profiles using prescribed equilibrium and some kinetic profiles. In this work we extend the RAPTOR transport model to include a time-varying plasma equilibrium geometry and verify the changes via comparison with ATSRA code simulations. In addition a new ad hoc transport model based on constant gradients and suitable for simulations of L-H and H-L mode transitions has been incorporated into the RAPTOR code and validated with rapid simulations of the time evolution of the safety factor and the electron temperature over the entire AUG and TCV discharges. An optimization procedure for the plasma termination phase has also been developed during this work. We define the goal of the optimization as ramping down the plasma current as fast as possible while avoiding any disruptions caused by reaching physical or technical limits. Our numerical study of this problem shows that a fast decrease of plasma elongation during current ramp-down can help in reducing plasma internal inductance. An early transition from H- to L-mode allows us to reduce the drop in poloidal beta, which is also important for plasma MHD stability and control. This work shows how these complex nonlinear interactions can be optimized automatically using relevant cost functions and constraints. Preliminary experimental results for TCV are demonstrated.

Mixed siliciclastic and carbonate sedimentation within Spar Mountain Member of Ste. Genevieve Limestone, Hamilton County, Illinois

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

Roberts, M.J.; Pryor, W.A.

1985-02-01

The Spar Mountain Member of the Ste. Genevieve Limestone (middle Mississippian) in Hamilton County, Illinois, consists of 40-60 ft (12-18 m) of interbedded limestones, shales, and sandstones. Five cores and 1400 electric logs were used to delineate two shallowing-upward carbonate cycles and 2 major clastic pulses within the Spar Mountain. Eight lithofacies representing 6 depositional environments were identified. They are: (A) echinoderm-brachiopod dolostone to packstone (outer ramp), (B) ooid-peloidal grainstone (intermediate ramp), (C) skeletal grainstone (intermediate ramp), (D) ooid-molluscan-intraclastic wackestone to grainstone (inner ramp), (E) pelletal-skeletal wackestone (inner ramp), (F) quartzarenite (channelized nearshore), (G) quartz-sublithic arenite to wacke (delta platform),more » and (H) quartz mudstone (prodelta, delta platform). Deposition occurred on a southwest-dipping carbonate ramp, with siliciclastic sediments originating from the northeast. The sequence of facies and their inferred depositional environments record 2 major progradational episodes. Oolitic facies are interpreted to be of tidal-bar belt origin and quartzarenite facies are interpreted to be of delta-distributary channel origin. Their distribution is partially controlled by antecedent and syndepositional topography. Many of these paleotopographic highes are positive features today and yield pinch-out stratigraphic relationships. Paleogeographic reconstructions demonstrate that the primary control on facies distribution was the position of the delta proper along strike. However, depositional topography also influenced sedimentation, particularly in the sand-sized fraction. Using this concept, better prediction of underlying porous buildups (ooid shoals) is possible if thickness of the overlying siliciclastic is known. Within buildups, a complex diagenetic history complicates the distribution of porosity.« less

Kinematic analysis of the thoracic limb of healthy dogs during descending stair and ramp exercises.

PubMed

Kopec, Nadia L; Williams, Jane M; Tabor, Gillian F

2018-01-01

OBJECTIVE To compare the kinematics of the thoracic limb of healthy dogs during descent of stairs and a ramp with those during a trot across a flat surface (control). ANIMALS 8 privately owned dogs. PROCEDURES For each dog, the left thoracic limb was instrumented with 5 anatomic markers to facilitate collection of 2-D kinematic data during each of 3 exercises (descending stairs, descending a ramp, and trotting over a flat surface). The stair exercise consisted of 4 steps with a 35° slope. For the ramp exercise, a solid plank was placed over the steps to create a ramp with a 35° slope. For the flat exercise, dogs were trotted across a flat surface for 2 m. Mean peak extension, peak flexion, and range of movement (ROM) of the shoulder, elbow, and carpal joints were compared among the 3 exercises. RESULTS Mean ROM for the shoulder and elbow joints during the stair exercise were significantly greater than during the flat exercise. Mean peak extension of the elbow joint during the flat exercise was significantly greater than that during both the stair and ramp exercises. Mean peak flexion of the elbow joint during the stair exercise was significantly greater than that during the flat exercise. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that descending stairs may be beneficial for increasing the ROM of the shoulder and elbow joints of dogs. Descending stair exercises may increase elbow joint flexion, whereas flat exercises may be better for targeting elbow joint extension.

Sound exposure changes European seabass behaviour in a large outdoor floating pen: Effects of temporal structure and a ramp-up procedure.

PubMed

Neo, Y Y; Hubert, J; Bolle, L; Winter, H V; Ten Cate, C; Slabbekoorn, H

2016-07-01

Underwater sound from human activities may affect fish behaviour negatively and threaten the stability of fish stocks. However, some fundamental understanding is still lacking for adequate impact assessments and potential mitigation strategies. For example, little is known about the potential contribution of the temporal features of sound, the efficacy of ramp-up procedures, and the generalisability of results from indoor studies to the outdoors. Using a semi-natural set-up, we exposed European seabass in an outdoor pen to four treatments: 1) continuous sound, 2) intermittent sound with a regular repetition interval, 3) irregular repetition intervals and 4) a regular repetition interval with amplitude 'ramp-up'. Upon sound exposure, the fish increased swimming speed and depth, and swam away from the sound source. The behavioural readouts were generally consistent with earlier indoor experiments, but the changes and recovery were more variable and were not significantly influenced by sound intermittency and interval regularity. In addition, the 'ramp-up' procedure elicited immediate diving response, similar to the onset of treatment without a 'ramp-up', but the fish did not swim away from the sound source as expected. Our findings suggest that while sound impact studies outdoors increase ecological and behavioural validity, the inherently higher variability also reduces resolution that may be counteracted by increasing sample size or looking into different individual coping styles. Our results also question the efficacy of 'ramp-up' in deterring marine animals, which warrants more investigation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Roles of CLR/RAMP Receptor Signaling in Reproduction and Development

PubMed Central

Chang, Chia Lin; Hsu, Sheau Yu Teddy

2016-01-01

Adrenomedullin (ADM), calcitonin gene-related peptides (α- and β-CGRPs), and intermedin/adrenomedullin 2 (IMD/ADM2) are major regulators of vascular tone and cardiovascular development in vertebrates. Recent research into their functions in reproduction has illuminated the role of these peptides and their cognate receptors (calcitonin receptor-like receptor/receptor activity-modifying protein (CLR/RAMP) receptors) in fetal–maternal blood circulation, feto-placental development, female gamete development, and gamete movement in the oviduct. Although ADM family peptides function in a temporally and spatially specific manner in various reproductive processes, they appear to act via a similar set of second messengers, including nitric oxide, cyclic GMP, cyclic AMP, and calcium-activated potassium channels in different tissues. These discoveries supported the view that CLR/RAMP receptors were recruited to perform a variety of newly evolved reproductive functions during the evolution of internal reproduction in mammals. These advances also provided insight into how CLR/RAMP receptor signaling pathways coordinate with other physiological adaptions to accommodate the extra metabolic needs during pregnancy, and captured some important details as to how fetal–maternal vascular communications are generated in the first place. Furthermore, these findings have revealed novel, promising opportunities for the prevention and treatment of aberrant pregnancies such as pregnancy-induced hypertension, preeclampsia, and tubal ectopic pregnancy. However, significant efforts are still needed to clarify the relationships between certain components of the CLR/RAMP signaling pathway and aberrant pregnancies before CLR/RAMP receptors can become targets for clinical management. With this understanding, this review summarizes recent progresses with particular focus on clinical implications. PMID:23745703

Chemistry of decomposition of freshwater wetland sedimentary organic material during ramped pyrolysis

NASA Astrophysics Data System (ADS)

Williams, E. K.; Rosenheim, B. E.

2011-12-01

Ramped pyrolysis methodology, such as that used in the programmed-temperature pyrolysis/combustion system (PTP/CS), improves radiocarbon analysis of geologic materials devoid of authigenic carbonate compounds and with low concentrations of extractable authochthonous organic molecules. The approach has improved sediment chronology in organic-rich sediments proximal to Antarctic ice shelves (Rosenheim et al., 2008) and constrained the carbon sequestration potential of suspended sediments in the lower Mississippi River (Roe et al., in review). Although ramped pyrolysis allows for separation of sedimentary organic material based upon relative reactivity, chemical information (i.e. chemical composition of pyrolysis products) is lost during the in-line combustion of pyrolysis products. A first order approximation of ramped pyrolysis/combustion system CO2 evolution, employing a simple Gaussian decomposition routine, has been useful (Rosenheim et al., 2008), but improvements may be possible. First, without prior compound-specific extractions, the molecular composition of sedimentary organic matter is unknown and/or unidentifiable. Second, even if determined as constituents of sedimentary organic material, many organic compounds have unknown or variable decomposition temperatures. Third, mixtures of organic compounds may result in significant chemistry within the pyrolysis reactor, prior to introduction of oxygen along the flow path. Gaussian decomposition of the reaction rate may be too simple to fully explain the combination of these factors. To relate both the radiocarbon age over different temperature intervals and the pyrolysis reaction thermograph (temperature (°C) vs. CO2 evolved (μmol)) obtained from PTP/CS to chemical composition of sedimentary organic material, we present a modeling framework developed based upon the ramped pyrolysis decomposition of simple mixtures of organic compounds (i.e. cellulose, lignin, plant fatty acids, etc.) often found in sedimentary organic material to account for changes in thermograph shape. The decompositions will be compositionally verified by 13C NMR analysis of pyrolysis residues from interrupted reactions. This will allow for constraint of decomposition temperatures of individual compounds as well as chemical reactions between volatilized moieties in mixtures of these compounds. We will apply this framework with 13C NMR analysis of interrupted pyrolysis residues and radiocarbon data from PTP/CS analysis of sedimentary organic material from a freshwater marsh wetland in Barataria Bay, Louisiana. We expect to characterize the bulk chemical composition during pyrolysis and as well as diagenetic changes with depth. Most importantly, we expect to constrain the potential and the limitations of this modeling framework for application to other depositional environments.

Safety performance functions for ramp terminals at diamond interchanges.

DOT National Transportation Integrated Search

2011-07-01

This report documents two efforts to support CDOT in the area of Safety Performance Function (SPF) : development. The first involved the data collection and development of SPFs for five categories of ramp : terminals at diamond interchanges. For each...

Kwik Bond Polymers(R) high friction surface treatment.

DOT National Transportation Integrated Search

2015-12-01

High friction surface treatment (HFST) was applied to two on-ramps in the Seattle urban area to improve : friction resistance. The ramps were high accident locations. The system applied was polyester resin binder and : calcined bauxite aggregate. Tes...

North side, showing ramp at western section but photograph taken ...

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

North side, showing ramp at western section but photograph taken to east of CO-172-BR-8 and looking southwesterly. - Fitzsimons General Hospital, Infirmary, Northwest Corner of East Bushnell Avenue & South Page Street, Aurora, Adams County, CO

Field test implementation of queue control : final report.

DOT National Transportation Integrated Search

2011-12-01

A major challenge for implementing queue control has been to accurately estimate on-ramp queue lengths, particularly during saturated onramp : conditions, when the vehicle queue extends around or beyond the ramp entrance. The main outcome of the rese...