WorldWideScience

Sample records for two-burn mid-level thrust

  1. Orienting Mid-Level Student Affairs Professionals

    Science.gov (United States)

    Mather, Peter C.; Bryan, Stephen P.; Faulkner, William O.

    2009-01-01

    Mid-level managers comprise a large proportion of student affairs organizations. They are often the most overlooked when it comes to professional orientation and institutional introduction when entering new positions. Accordingly, information is presented from the professional literature that speaks to the characteristics and unique needs of this…

  2. Mining Mid-level Features for Image Classification

    OpenAIRE

    Fernando, Basura; Fromont, Elisa; Tuytelaars, Tinne

    2014-01-01

    International audience; Mid-level or semi-local features learnt using class-level information are potentially more distinctive than the traditional low-level local features constructed in a purely bottom-up fashion. At the same time they preserve some of the robustness properties with respect to occlusions and image clutter. In this paper we propose a new and effective scheme for extracting mid-level features for image classification, based on relevant pattern mining. In par- ticular, we mine...

  3. Construction of the Mid-Level Management Position

    Science.gov (United States)

    Tyrell, Steve

    2014-01-01

    The role of the mid-level manager as an organizer, communicator, and problem-solver in student affairs has been examined within the literature, but current discussion generally excludes the perspective of managers at community colleges. This chapter focuses on the importance of managerial identity and roles, particularly as it is enacted within a…

  4. Construction of the Mid-Level Management Position

    Science.gov (United States)

    Tyrell, Steve

    2014-01-01

    The role of the mid-level manager as an organizer, communicator, and problem-solver in student affairs has been examined within the literature, but current discussion generally excludes the perspective of managers at community colleges. This chapter focuses on the importance of managerial identity and roles, particularly as it is enacted within a…

  5. Impact of Rhythm on Vietnamese Adult EFL Learners Intelligibility in Term of Mid-level Tone

    Directory of Open Access Journals (Sweden)

    Tien DANG

    2013-07-01

    Full Text Available This study investigates the impact of L1 (Vietnamese on L2 (English with a specific reference to rhythm. The transfer of L1 rhythm to the L2 rhythm is considered as a potential factor in reducing EFL learner’s intelligibility.  The findings of this quantitative research show that Vietnamese adult EFL learners’ oral output is significantly unintelligible due to the application the mid-level tone of their first language, part of Vietnamese rhythm to produce English rhythm in a pronunciation test, making their utterance monotonous. This paper aims at presenting findings gained from an examination into how the Vietnamese rhythm, the mid-level tone, affects 50 Vietnamese adult EFL learners’ intelligibility in a pronunciation test assessed by ten judges. Key words: rhythm, mid-level tone, Vietnamese adult EFL learners, and intelligibility

  6. Clocked Thrust Reversers

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2017-01-01

    An aircraft includes a fuselage including a propulsion system supported within an aft portion. A thrust reverser is mounted proximate to the propulsion system for directing thrust in a direction to slow the aircraft. The thrust reverser directs thrust at an angle relative to a vertical plane to reduce interference on control surfaces and reduce generation of underbody lift.

  7. SuperPixel based mid-level image description for image recognition

    NARCIS (Netherlands)

    Tasli, H.E.; Sicre, R.; Gevers, T.

    2015-01-01

    This study proposes a mid-level feature descriptor and aims to validate improvement on image classification and retrieval tasks. In this paper, we propose a method to explore the conventional feature extraction techniques in the image classification pipeline from a different perspective where

  8. 22 CFR 11.11 - Mid-level Foreign Service officer career candidate appointments.

    Science.gov (United States)

    2010-04-01

    ... affirmative factor in the selection of candidates for appointment as Foreign Service officer career candidates..., experience, and skills needed by the Foreign Service at the mid-level. (3) Age. All career candidate... terminated and the candidate so informed. (10) Foreign language requirement. All candidates who pass the...

  9. Developing a new mid-level health worker: lessons from South Africa's experience with clinical associates

    Directory of Open Access Journals (Sweden)

    Sharon Fonn

    2013-01-01

    Full Text Available Background: Mid-level medical workers play an important role in health systems and hold great potential for addressing the human resource shortage, especially in low- and middle-income countries. South Africa began the production of its first mid-level medical workers – known as clinical associates – in small numbers in 2008. Objective: We describe the way in which scopes of practice and course design were negotiated and assess progress during the early years. We derive lessons for other countries wishing to introduce new types of mid-level worker. Methods: We conducted a rapid assessment in 2010 consisting of a review of 19 documents and 11 semi-structured interviews with a variety of stakeholders. A thematic analysis was performed. Results: Central to the success of the clinical associate training programme was a clear definition and understanding of the interests of various stakeholders. Stakeholder sensitivities were taken into account in the conceptualisation of the role and scope of practice of the clinical associate. This was achieved by dealing with quality of care concerns through service-based training and doctor supervision, and using a national curriculum framework to set uniform standards. Conclusions: This new mid-level medical worker can contribute to the quality of district hospital care and address human resource shortages. However, a number of significant challenges lie ahead. To sustain and expand on early achievements, clinical associates must be produced in greater numbers and the required funding, training capacity, public sector posts, and supervision must be made available. Retaining the new cadre will depend on the public system becoming an employer of choice. Nonetheless, the South African experience yields positive lessons that could be of use to other countries contemplating similar initiatives.

  10. Cameroon mid-level providers offer a promising public health dentistry model

    Directory of Open Access Journals (Sweden)

    Achembong Leo

    2012-11-01

    Full Text Available Background Oral health services are inadequate and unevenly distributed in many developing countries, particularly those in sub-Saharan Africa. Rural areas in these countries and poorer sections of the population in urban areas often do not have access to oral health services mainly because of a significant shortage of dentists and the high costs of care. We reviewed Cameroon’s experience with deploying a mid-level cadre of oral health professionals and the feasibility of establishing a more formal and predictable role for these health workers. We anticipate that a task-shifting approach in the provision of dental care will significantly improve the uneven distribution of oral health services particularly in the rural areas of Cameroon, which is currently served by only 3% of the total number of dentists. Methods The setting of this study was the Cameroon Baptist Convention Health Board (BCHB, which has four dentists and 42 mid-level providers. De-identified data were collected manually from the registries of 10 Baptist Convention clinics located in six of Cameroon’s 10 regions and then entered into an Excel format before importing into STATA. A retrospective abstraction of all entries for patient visits starting October 2010, and going back in time until 1500 visits were extracted from each clinic. Results This study showed that mid-level providers in BCHB clinics are offering a full scope of dental work across the 10 clinics, with the exception of treatment for major facial injuries. Mid-level providers alone performed 93.5% of all extractions, 87.5% of all fillings, 96.5% of all root canals, 97.5% of all cleanings, and 98.1% of all dentures. The dentists also typically played a teaching role in training the mid-level providers. Conclusions The Ministry of Health in Cameroon has an opportunity to learn from the BCHB model to expand access to oral health care across the country. This study shows the benefits of using a simple, workable, low

  11. Hydrogeologic Conditions at the DUSEL Mid-level Campus and Implications for Large Cavern Design

    Science.gov (United States)

    Weinig, W. T.; Popielak, R. S.; Stetler, L. D.

    2010-12-01

    In July 2007 the former Homestake gold mine in Lead, South Dakota was selected as the site of a new Deep Underground Science and Engineering Laboratory (DUSEL). The mid-level campus, including several new, large excavations, is planned for development at the 4850 Level of the facility (1,489 meters below surface datum) near the former location of the neutrino experiment conducted by Dr. Ray Davis starting in about 1965. The mid-level campus will host a wide range of scientific research to be conducted in an environment that minimizes the influence of cosmic radiation. While operating, Homestake was the deepest underground mine in North America, with workings reaching over 2,439 meters deep. In June 2003, mining had ceased and the dewatering pumps were turned off. The resultant flooding reached a level approximately 98 meters above the planned mid-level campus before dewatering pumps were turned back on in June 2008. In May 2009, water levels fell below the 4850 Level of the DUSEL facility allowing commencement of development work for the mid-level campus. Data collected prior to the cessation of mining indicated long-term average groundwater inflows of 1900 liters/minute (L/min) to 2600 L/min. For a mine with over 480 kilometers of workings, this represents a relatively small groundwater flux, consistent with reported hydraulic conductivities of 10-5 centimeters per second (cm/sec) to 10-7 cm/sec. Recent calculations based on analysis of dewatering data indicate a bulk hydraulic conductivity of 10-6 to 10-7 cm/sec. Data collected during a geotechnical investigation in 2009 indicated discharges from new boreholes in the area of the planned mid-level campus of less than 0.25 liters per minute. Shut-in pressures measured over relatively brief periods during the investigation ranged from zero to 4.1 megaPascals (MPa). Data collected during drilling and subsequent borehole televiewer logs showed relatively distributed inflows throughout the length of the boreholes. A

  12. Observations of ice multiplication in a weakly convective cell embedded in supercooled mid-level stratus

    Directory of Open Access Journals (Sweden)

    J. Crosier

    2010-08-01

    Full Text Available Simultaneous observations of cloud microphysical properties were obtained by in-situ aircraft measurements and ground based Radar/Lidar. Widespread mid-level stratus cloud was present below a temperature inversion (~5 °C magnitude at 3.6 km altitude. Localised convection (peak updraft 1.5 m s−1 was observed 20 km west of the Radar station. This was associated with convergence at 2.5 km altitude. The convection was unable to penetrate the inversion capping the mid-level stratus.

    The mid-level stratus cloud was vertically thin (~400 m, horizontally extensive (covering 100 s of km and persisted for more than 24 h. The cloud consisted of supercooled water droplets and small concentrations of large (~1 mm stellar/plate like ice which slowly precipitated out. This ice was nucleated at temperatures greater than −12.2 °C and less than −10.0 °C, (cloud top and cloud base temperatures, respectively. No ice seeding from above the cloud layer was observed. This ice was formed by primary nucleation, either through the entrainment of efficient ice nuclei from above/below cloud, or by the slow stochastic activation of immersion freezing ice nuclei contained within the supercooled drops. Above cloud top significant concentrations of sub-micron aerosol were observed and consisted of a mixture of sulphate and carbonaceous material, a potential source of ice nuclei.

    Precipitation from the mid-level stratus evaporated before reaching the surface, whereas rates of up to 1 mm h−1 were observed below the convective feature. There is strong evidence for the Hallett-Mossop (HM process of secondary ice particle production leading to the formation of the precipitation observed. This includes (1 Ice concentrations in the convective feature were more than an order of magnitude greater than the concentration of primary ice in the overlaying stratus, (2 Large concentrations of small pristine columns were observed at the ~−5

  13. Ubiquity and impact of thin mid-level clouds in the tropics.

    Science.gov (United States)

    Bourgeois, Quentin; Ekman, Annica M L; Igel, Matthew R; Krejci, Radovan

    2016-08-17

    Clouds are crucial for Earth's climate and radiation budget. Great attention has been paid to low, high and vertically thick tropospheric clouds such as stratus, cirrus and deep convective clouds. However, much less is known about tropospheric mid-level clouds as these clouds are challenging to observe in situ and difficult to detect by remote sensing techniques. Here we use Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite observations to show that thin mid-level clouds (TMLCs) are ubiquitous in the tropics. Supported by high-resolution regional model simulations, we find that TMLCs are formed by detrainment from convective clouds near the zero-degree isotherm. Calculations using a radiative transfer model indicate that tropical TMLCs have a cooling effect on climate that could be as large in magnitude as the warming effect of cirrus. We conclude that more effort has to be made to understand TMLCs, as their influence on cloud feedbacks, heat and moisture transport, and climate sensitivity could be substantial.

  14. Air Force Core Values: An Analysis of Mid-Level Career Officers' Values and Their Suitability to Instill Them

    National Research Council Canada - National Science Library

    Keith, Steven

    1997-01-01

    .... To these concerns, this research seeks to evaluate the level of integration of Air Force core values in mid-level career officers, and their subsequent suitability to help instill the core values in subordinates...

  15. PPT Thrust Stand

    Science.gov (United States)

    Haag, Thomas W.

    1995-01-01

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

  16. Exploring the source of the mid-level hump for intensity discrimination in quiet and the effects of noisea)

    Science.gov (United States)

    Roverud, Elin; Strickland, Elizabeth A.

    2015-01-01

    Intensity discrimination Weber fractions (WFs) measured for short, high-frequency tones in quiet are larger at mid levels than at lower or higher levels. The source of this “mid-level hump” is a matter of debate. One theory is that the mid-level hump reflects basilar-membrane compression, and that WFs decrease at higher levels due to spread-of-excitation cues. To test this theory, Experiment 1 measured the mid-level hump and growth-of-masking functions to estimate the basilar membrane input/output (I/O) function in the same listeners. Results showed the initial rise in WFs could be accounted for by the change in I/O function slope, but there was additional unexplained variability in WFs. Previously, Plack [(1998). J. Acoust. Soc. Am. 103(5), 2530–2538] showed that long-duration notched noise (NN) presented with the tone reduced the mid-level hump even with a temporal gap in the NN. Plack concluded the results were consistent with central profile analysis. However, simultaneous, forward, and backward NN were not examined separately, which may independently test peripheral and central mechanisms of the NN. Experiment 2 measured WFs at the mid-level hump in the presence of NN and narrowband noise of different durations and temporal positions relative to the tone. Results varied across subjects, but were consistent with more peripheral mechanisms. PMID:25786945

  17. Exploring the source of the mid-level hump for intensity discrimination in quiet and the effects of noise.

    Science.gov (United States)

    Roverud, Elin; Strickland, Elizabeth A

    2015-03-01

    Intensity discrimination Weber fractions (WFs) measured for short, high-frequency tones in quiet are larger at mid levels than at lower or higher levels. The source of this "mid-level hump" is a matter of debate. One theory is that the mid-level hump reflects basilar-membrane compression, and that WFs decrease at higher levels due to spread-of-excitation cues. To test this theory, Experiment 1 measured the mid-level hump and growth-of-masking functions to estimate the basilar membrane input/output (I/O) function in the same listeners. Results showed the initial rise in WFs could be accounted for by the change in I/O function slope, but there was additional unexplained variability in WFs. Previously, Plack [(1998). J. Acoust. Soc. Am. 103(5), 2530-2538] showed that long-duration notched noise (NN) presented with the tone reduced the mid-level hump even with a temporal gap in the NN. Plack concluded the results were consistent with central profile analysis. However, simultaneous, forward, and backward NN were not examined separately, which may independently test peripheral and central mechanisms of the NN. Experiment 2 measured WFs at the mid-level hump in the presence of NN and narrowband noise of different durations and temporal positions relative to the tone. Results varied across subjects, but were consistent with more peripheral mechanisms.

  18. Assessment of a career development program for executive amd mid-level managers

    Science.gov (United States)

    Swanson, James R., Sr.

    1994-01-01

    This project sought to validate the competencies required of mid-level and executive managers at the Kennedy Space Center (KSC), in order to enable an assessment of the Resident Management Education Program (RMEP). Forty (40) statements describing management competencies were presented to a sample of 37 KSC managers, who judged each as essential, useful but not essential, or not needed at each of two management levels. A content validity ratio (CVR) was calculated for each competency statement at the two management levels. There was general agreement on the validity of 36 or the 40 competency statements. Based on the content validity ratios and comments from respondents, recommendations for improvement of the RMEP were made.

  19. FPGA-Based Multimodal Embedded Sensor System Integrating Low- and Mid-Level Vision

    Directory of Open Access Journals (Sweden)

    Uwe Meyer-Baese

    2011-08-01

    Full Text Available Motion estimation is a low-level vision task that is especially relevant due to its wide range of applications in the real world. Many of the best motion estimation algorithms include some of the features that are found in mammalians, which would demand huge computational resources and therefore are not usually available in real-time. In this paper we present a novel bioinspired sensor based on the synergy between optical flow and orthogonal variant moments. The bioinspired sensor has been designed for Very Large Scale Integration (VLSI using properties of the mammalian cortical motion pathway. This sensor combines low-level primitives (optical flow and image moments in order to produce a mid-level vision abstraction layer. The results are described trough experiments showing the validity of the proposed system and an analysis of the computational resources and performance of the applied algorithms.

  20. Observations of ice multiplication in a weakly convective cell embedded in supercooled mid-level stratus

    Directory of Open Access Journals (Sweden)

    J. Crosier

    2011-01-01

    Full Text Available Simultaneous observations of cloud microphysical properties were obtained by in-situ aircraft measurements and ground based Radar/Lidar. Widespread mid-level stratus cloud was present below a temperature inversion (~5 °C magnitude at 3.6 km altitude. Localised convection (peak updraft 1.5 m s−1 was observed 20 km west of the Radar station. This was associated with convergence at 2.5 km altitude. The convection was unable to penetrate the inversion capping the mid-level stratus.

    The mid-level stratus cloud was vertically thin (~400 m, horizontally extensive (covering 100 s of km and persisted for more than 24 h. The cloud consisted of supercooled water droplets and small concentrations of large (~1 mm stellar/plate like ice which slowly precipitated out. This ice was nucleated at temperatures greater than −12.2 °C and less than −10.0 °C, (cloud top and cloud base temperatures, respectively. No ice seeding from above the cloud layer was observed. This ice was formed by primary nucleation, either through the entrainment of efficient ice nuclei from above/below cloud, or by the slow stochastic activation of immersion freezing ice nuclei contained within the supercooled drops. Above cloud top significant concentrations of sub-micron aerosol were observed and consisted of a mixture of sulphate and carbonaceous material, a potential source of ice nuclei. Particle number concentrations (in the size range 0.1<D<3.0 μm were measured above and below cloud in concentrations of ~25 cm−3. Ice crystal concentrations in the cloud were constant at around 0.2 L−1. It is estimated that entrainment of aerosol particles into cloud cannot replenish the loss of ice nuclei from the cloud layer via precipitation.

    Precipitation from the mid-level stratus evaporated before reaching the surface, whereas rates of up to 1 mm h−1 were observed below the convective feature. There is strong

  1. The effects of ipsilateral, contralateral, and bilateral broadband noise on the mid-level hump in intensity discrimination.

    Science.gov (United States)

    Roverud, Elin; Strickland, Elizabeth A

    2015-11-01

    Previous psychoacoustical and physiological studies indicate that the medial olivocochlear reflex (MOCR), a bilateral, sound-evoked reflex, may lead to improved sound intensity discrimination in background noise. The MOCR can decrease the range of basilar-membrane compression and can counteract effects of neural adaptation from background noise. However, the contribution of these processes to intensity discrimination is not well understood. This study examined the effect of ipsilateral, contralateral, and bilateral noise on the "mid-level hump." The mid-level hump refers to intensity discrimination Weber fractions (WFs) measured for short-duration, high-frequency tones which are poorer at mid levels than at lower or higher levels. The mid-level hump WFs may reflect a limitation due to basilar-membrane compression, and thus may be decreased by the MOCR. The noise was either short (50 ms) or long (150 ms), with the long noise intended to elicit the sluggish MOCR. For a tone in quiet, mid-level hump WFs improved with ipsilateral noise for most listeners, but not with contralateral noise. For a tone in ipsilateral noise, WFs improved with contralateral noise for most listeners, but only when both noises were long. These results are consistent with MOCR-induced WF improvements, possibly via decreases in effects of compression and neural adaptation.

  2. Powertrain Component Inspection from Mid-Level Blends Vehicle Aging Study

    Energy Technology Data Exchange (ETDEWEB)

    Shoffner, Brent [Southwest Research Institute, San Antonio; Johnson, Ryan [Southwest Research Institute, San Antonio; Heimrich, Martin J. [Southwest Research Institute, San Antonio; Lochte, Michael [Southwest Research Institute, San Antonio

    2010-11-01

    The Energy Independence and Security Act of 2007 calls on the nation to significantly increase its use of renewable fuels to meet its transportation energy needs. The law expands the renewable fuel standard to require use of 36 billion gallons of renewable fuel by 2022. Given that ethanol is the most widely used renewable fuel in the U.S. market, ethanol will likely make up a significant portion of the 36-billion-gallon requirement. The vast majority of ethanol used in the United States is blended with gasoline to create E10-gasoline with up to 10% ethanol. The remaining ethanol is sold in the form of E85 - a gasoline blend with as much as 85% ethanol that can only be used in flexible-fuel vehicles (FFVs). Consumption of E85 is at present limited by both the size of the FFV fleet and the number of E85 fueling stations. Gasoline consumption in the United States is currently about 140 billion gallons per year; thus the maximum use of ethanol as E10 is only about 14 billion gallons. While the U.S. Department of Energy (DOE) remains committed to expanding the E85 infrastructure, that market represented less than 1% of the ethanol consumed in 2010 and will not be able to absorb projected volumes of ethanol in the near term. Because of these factors, DOE and others have been assessing the viability of using mid-level ethanol blends (E15 or E20) as a way to accommodate growing volumes of ethanol. The DOE Mid-Level Ethanol Blends Test Program has been under way since 2007, supported jointly by the Office of the Biomass Program and the Vehicle Technologies Program. One of the larger projects, the Catalyst Durability Study, or Vehicle Aging Study, will be completed early in calendar year 2011. The following report describes a subproject of the Vehicle Aging Study in which powertrain components from 18 of the vehicles were examined at Southwest Research Institute under contract to Oak Ridge National Laboratory (ORNL).

  3. Thrust stand for low-thrust liquid pulsed rocket engines.

    Science.gov (United States)

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

    2010-09-01

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

  4. The harm principle as a mid-level principle?: three problems from the context of infectious disease control.

    Science.gov (United States)

    Krom, André

    2011-10-01

    Effective infectious disease control may require states to restrict the liberty of individuals. Since preventing harm to others is almost universally accepted as a legitimate (prima facie) reason for restricting the liberty of individuals, it seems plausible to employ a mid-level harm principle in infectious disease control. Moral practices like infectious disease control support - or even require - a certain level of theory-modesty. However, employing a mid-level harm principle in infectious disease control faces at least three problems. First, it is unclear what we gain by attaining convergence on a specific formulation of the harm principle. Likely candidates for convergence, a harm principle aimed at preventing harmful conduct, supplemented by considerations of effectiveness and always choosing the least intrusive means still leave ample room for normative disagreement. Second, while mid-level principles are sometimes put forward in response to the problem of normative theories attaching different weight to moral principles, employing a mid-level harm principle completely leaves open how to determine what weight to attach to it in application. Third, there appears to be a trade-off between attaining convergence and finding a formulation of the harm principle that can justify liberty-restrictions in all situations of contagion, including interventions that are commonly allowed. These are not reasons to abandon mid-level theorizing altogether. But there is no reason to be too theory-modest in applied ethics. Morally justifying e.g. if a liberty-restriction in infectious disease control is proportional to the aim of harm-prevention, promptly requires moving beyond the mid-level harm principle. © 2011 Blackwell Publishing Ltd.

  5. Army Reserve Instructors' Perceptions regarding the Effectiveness of the Experiential Learning Model in Teaching Mid-Level Army Reserve Officers

    Science.gov (United States)

    Meyer, Robert S.

    2010-01-01

    The Command and General Staff College (CGSC) at Ft. Leavenworth is a fully accredited graduate school. The primary professional development program at CGSC has been for mid-level officers. This program is referred to as ILE (Intermediate Level Education) and is taught in small cohort groups of 12 to 18 students. CGSC has embraced the principles of…

  6. The Effective Practices and Beliefs of School Principals in High Achieving Hispanic Majority Mid-Level Schools

    Science.gov (United States)

    Briseno, Johnny

    2010-01-01

    This qualitative phenomenological research study used narrative inquiry to investigate the effective practices and beliefs of 10 Texas principals in high achieving majority Hispanic mid-level schools. Participant interviews were analyzed using the Creswell (2007) six step method for analyzing phenomenological studies. Findings from this study…

  7. The Harm Principle as a Mid-level Principle? Three Problems from the Context of Infectious Disease Control

    NARCIS (Netherlands)

    Krom, A.

    2011-01-01

    Effective infectious disease control may require states to restrict the liberty of individuals. Since preventing harm to others is almost universally accepted as a legitimate (prima facie) reason for restricting the liberty of individuals, it seems plausible to employ a mid-level harm principle in i

  8. Measuring and managing the work environment of the mid-level provider – the neglected human resource

    Directory of Open Access Journals (Sweden)

    McAuliffe Eilish

    2009-02-01

    Full Text Available Abstract Background Much has been written in the past decade about the health workforce crisis that is crippling health service delivery in many middle-income and low-income countries. Countries having lost most of their highly qualified health care professionals to migration increasingly rely on mid-level providers as the mainstay for health services delivery. Mid-level providers are health workers who perform tasks conventionally associated with more highly trained and internationally mobile workers. Their training usually has lower entry requirements and is for shorter periods (usually two to four years. Our study aimed to explore a neglected but crucial aspect of human resources for health in Africa: the provision of a work environment that will promote motivation and performance of mid-level providers. This paper explores the work environment of mid-level providers in Malawi, and contributes to the validation of an instrument to measure the work environment of mid-level providers in low-income countries. Methods Three districts were purposively sampled from each of the three geographical regions in Malawi. A total of 34 health facilities from the three districts were included in the study. All staff in each of the facilities were included in the sampling frame. A total of 153 staff members consented to be interviewed. Participants completed measures of perceptions of work environment, burnout and job satisfaction. Findings The Healthcare Provider Work Index, derived through Principal Components Analysis and Rasch Analysis of our modification of an existing questionnaire, constituted four subscales, measuring: (1 levels of staffing and resources; (2 management support; (3 workplace relationships; and (4 control over practice. Multivariate analysis indicated that scores on the Work Index significantly predicted key variables concerning motivation and attrition such as emotional exhaustion, job satisfaction, satisfaction with the profession

  9. Summary of High-Octane Mid-Level Ethanol Blends Study

    Energy Technology Data Exchange (ETDEWEB)

    Theiss, Timothy J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Alleman, Teresa [National Renewable Energy Lab. (NREL), Golden, CO (United States); Brooker, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Elgowainy, Amgad [Argonne National Lab. (ANL), Argonne, IL (United States); Fioroni, Gina [National Renewable Energy Lab. (NREL), Golden, CO (United States); Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States); Huff, Shean P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnson, Caley [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kass, Michael D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leiby, Paul Newsome [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Martinez, Rocio Uria [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McCormick, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Moriarty, Kristi [National Renewable Energy Lab. (NREL), Golden, CO (United States); Newes, Emily [National Renewable Energy Lab. (NREL), Golden, CO (United States); Oladosu, Gbadebo A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Szybist, James P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Thomas, John F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); West, Brian H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-07-01

    Original equipment manufacturers (OEMs) of light-duty vehicles are pursuing a broad portfolio of technologies to reduce CO2 emissions and improve fuel economy. Central to this effort is higher efficiency spark ignition (SI) engines, including technologies reliant on higher compression ratios and fuels with improved anti-knock properties, such as gasoline with significantly increased octane numbers. Ethanol has an inherently high octane number and would be an ideal octane booster for lower-octane petroleum blendstocks. In fact, recently published data from Department of Energy (DOE) national laboratories (Splitter and Szybist, 2014a, 2014b; Szybist, 2010; Szybist and West, 2013) and OEMs (Anderson, 2013) and discussions with the U.S. Environmental Protection Agency (EPA) suggest the potential of a new high octane fuel (HOF) with 25–40 vol % of ethanol to assist in reaching Renewable Fuel Standard (RFS2) and greenhouse gas (GHG) emissions goals. This mid-level ethanol content fuel, with a research octane number (RON) of about 100, appears to enable efficiency improvements in a suitably calibrated and designed engine/vehicle system that are sufficient to offset its lower energy density (Jung, 2013; Thomas, et al, 2015). This efficiency improvement would offset the tank mileage (range) loss typically seen for ethanol blends in conventional gasoline and flexible-fuel vehicles (FFVs). The prospects for such a fuel are additionally attractive because it can be used legally in over 18 million FFVs currently on the road. Thus the legacy FFV fleet can serve as a bridge by providing a market for the new fuel immediately, so that future vehicles will have improved efficiency as the new fuel becomes widespread. In this way, HOF can simultaneously help improve fuel economy while expanding the ethanol market in the United States via a growing market for an ethanol blend higher than E10. The DOE Bioenergy Technologies Office initiated a collaborative research program

  10. An Investigation of the Relationship between Performance Appraisal and Career Development and Advancement of Mid-Level Women in Student Affairs Administration

    Science.gov (United States)

    Corral, Christine R.

    2009-01-01

    The purpose of this study was to explore the performance appraisal experience of 14 mid-level women in student affairs administration at four-year colleges and universities in Northern Illinois using a qualitative research approach involving personal interviews. Previous research on career development and advancement of mid-level women in student…

  11. Service delivery in Kenyan district hospitals – what can we learn from literature on mid-level managers?

    Science.gov (United States)

    2013-01-01

    Background There is a growing emphasis on the need to tackle inadequate human resources for health (HRH) as an essential part of strengthening health systems; but the focus is mostly on macro-level issues, such as training, recruitment, skill mix and distribution. Few attempts have been made to understand the capability of health workers, their motivation and other structural and organizational aspects of systems that influence workforce performance. We have examined literature on the roles of mid-level managers to help us understand how they might influence service delivery quality in Kenyan hospitals. In the Kenyan hospital settings, these are roles that head of departments who are also clinical or nursing service providers might play. Methods A computerized search strategy was run in Pub Med, Cochrane Library, Directory of Open Access Journals Social Science Research Network, Eldis, Google Scholar and Human Resources for Health web site databases using both free-text and MeSH terms from 1980 to 2011. In addition, citation searching from excluded and included articles was used and relevant unpublished literature systematically identified. Results and discussion A total of 23 articles were finally included in the review from over 7000 titles and abstracts initially identified. The most widely documented roles of mid-level managers were decision-making or problem-solving, strategist or negotiator and communicator. Others included being a therapist or motivator, goal setting or articulation and mentoring or coaching. In addition to these roles, we identified important personal attributes of a good manager, which included interpersonal skills, delegation and accountability, and honesty. The majority of studies included in the review concerned the roles that mid-level managers are expected to play in times of organizational change. Conclusion This review highlights the possible significance of mid-level managers in achieving delivery of high-quality services in Kenyan

  12. Recommended Practices in Thrust Measurements

    Science.gov (United States)

    Polk, James E.; Pancotti, Anthony; Haag, Thomas; King, Scott; Walker, Mitchell; Blakely, Joseph; Ziemer, John

    2013-01-01

    Accurate, direct measurement of thrust or impulse is one of the most critical elements of electric thruster characterization, and one of the most difficult measurements to make. The American Institute of Aeronautics and Astronautics has started an initiative to develop standards for many important measurement processes in electric propulsion, including thrust measurements. This paper summarizes recommended practices for the design, calibration, and operation of pendulum thrust stands, which are widely recognized as the best approach for measuring micro N- to mN-level thrust and micro Ns-level impulse bits. The fundamentals of pendulum thrust stand operation are reviewed, along with its implementation in hanging pendulum, inverted pendulum, and torsional balance configurations. Methods of calibration and recommendations for calibration processes are presented. Sources of error are identified and methods for data processing and uncertainty analysis are discussed. This review is intended to be the first step toward a recommended practices document to help the community produce high quality thrust measurements.

  13. Reducing Thrusts In Solid-Fuel Rockets

    Science.gov (United States)

    Bement, Laurence J.

    1989-01-01

    Thrust-terminating system conceived to reduce thrust of solid-propellant rocket motor in controlled manner such that thrust loads not increased or decreased beyond predictable levels. Concept involves explosively cutting opposing venting pairs in case of rocket motor above nozzles to initiate venting of chamber and reduction of thrust. Vents sized and numbered to control amount and rate of reduction in thrust.

  14. Low-thrust rocket trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Keaton, P.W.

    1986-01-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report. 57 refs., 10 figs.

  15. Low-thrust rocket trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Keaton, P.W.

    1987-03-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report.

  16. Improved Rhenium Thrust Chambers

    Science.gov (United States)

    O'Dell, John Scott

    2015-01-01

    Radiation-cooled bipropellant thrust chambers are being considered for ascent/ descent engines and reaction control systems on various NASA missions and spacecraft, such as the Mars Sample Return and Orion Multi-Purpose Crew Vehicle (MPCV). Currently, iridium (Ir)-lined rhenium (Re) combustion chambers are the state of the art for in-space engines. NASA's Advanced Materials Bipropellant Rocket (AMBR) engine, a 150-lbf Ir-Re chamber produced by Plasma Processes and Aerojet Rocketdyne, recently set a hydrazine specific impulse record of 333.5 seconds. To withstand the high loads during terrestrial launch, Re chambers with improved mechanical properties are needed. Recent electrochemical forming (EL-Form"TM") results have shown considerable promise for improving Re's mechanical properties by producing a multilayered deposit composed of a tailored microstructure (i.e., Engineered Re). The Engineered Re processing techniques were optimized, and detailed characterization and mechanical properties tests were performed. The most promising techniques were selected and used to produce an Engineered Re AMBR-sized combustion chamber for testing at Aerojet Rocketdyne.

  17. THRUST REVERSER PERFORMANCE AND THE INGESTION PROBLEM,

    Science.gov (United States)

    THRUST REVERSAL, INGESTION ), (*JET TRANSPORT PLANE, THRUST), (*TURBOJET ENGINES, INGESTION ), JET TRANSPORT PLANES, PELLETS, ROCK (GEOLOGY), PARTICLES, DESIGN, MODEL, INSTALLATION, EFFECTIVENESS, COMMERICAL.

  18. CULTUROLOGICAL APPROACH IN THE SYSTEM OF ETHODOLOGICAL APPROACHES TO TRAINING IN COLLEGES OF MID-LEVEL LAWYERS

    Directory of Open Access Journals (Sweden)

    Tatiana Vasilieva

    2015-01-01

    Full Text Available The article describes the essential relationship of culturalogical approach to vocational training in secondary vocational education of mid-level future lawyers and competence-based, qualitative and quality oriented, prognostic approaches to vocational education. The authors reveal the essence of the concept of “professional culture of a mid-level lawyer”, present the characteristics of some components of this culture; consider the factors and conditions that affect the efficiency of the process of formation and development of College foundations of professional culture of future graduates majoring in “Law and organization of social security". Also the article reveals the content and functionality of the professional culture of lawyers’ profile of social services. The authors state that the professional culture of a socio-humanitarian profile specialist has two levels (two "plans", self-unfolding circuit: internal and external, give detailed characteristics of each of these levels. Special attention is paid to the relationship of the concepts of «professional culture» and «professional competence» of the specialist of social sciences and humanities (including law profile. The article proves the thesis that the synthesis of cultural, competence, qualitative, and predictive approaches to the development of professional training of law profile specialists ensures multifunctional training of future specialists in the context of scientifically based prediction of their future employability at the modern labor market and to address specific professional problems (including the regional ones of improving the quality of human rights and legal services provided to Russian citizens.

  19. Aircraft Horizontal Thrust Measurement Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility is designed to support the DoD mission by providing unique air vehicle installed engine performance (thrust output) measurements. This system consists...

  20. Army (MANTECH) Thrust Area Concept: Optics Thrust Area

    Science.gov (United States)

    Kopacz, Stanley P.

    1992-01-01

    With the shrinking of the U.S. Army's material needs and the compression of defense requirements, the Army Manufacturing Technology (MANTECH) Program has the opportunity to advance the manufacturing state-of-the-art and solve near term production problems of the U.S. industrial base. To exploit this opportunity, the Army restructured its MANTECH efforts in FY 90 based on a thrust area concept. Each of the ten current thrusts, directed by a thrust area manager, has a broad technical objective selected to improve specific manufacturing processes. The manager is charged with setting objectives, selecting tasks, monitoring execution, leveraging external resources, and establishing microfactories to promote technology transfer. The Optics Manufacturing Thrust is an example of the concept. It is currently directed at revitalizing the domestic precision optics manufacturing base, now characterized by high labor costs and 1940's technology, through introduction of revolutionary machines, new processes, and Computer Integrated Manufacturing (CIM) principles. Leveraging of MANTECH dollars with those of industry, academia, and state governments led to the establishment of the center for Optics Manufacturing and plans for regional centers. Recognition of the U.S. as a world leader in precision optics manufacturing and a dramatic reduction of both manufacturing time and cost should accrue from thrust area efforts.

  1. Evaluation of fluidic thrust vectoring nozzle via thrust pitching angle and thrust pitching moment

    Science.gov (United States)

    Li, L.; Hirota, M.; Ouchi, K.; Saito, T.

    2016-03-01

    Shock vector control (SVC) in a converging-diverging nozzle with a rectangular cross-section is discussed as a fluidic thrust vectoring (FTV) method. The interaction between the primary nozzle flow and the secondary jet is examined using experiments and numerical simulations. The relationships between FTV parameters [nozzle pressure ratio (NPR) and secondary jet pressure ratio (SPR)] and FTV performance (thrust pitching angle and thrust pitching moment) are investigated. The experiments are conducted with an NPR of up to 10 and an SPR of up to 2.7. Numerical simulations of the nozzle flow are performed using a Navier-Stokes solver with input parameters set to match the experimental conditions. The thrust pitching angle and moment computed from the force-moment balance are used to evaluate FTV performance. The experiment and numerical results indicate that the FTV parameters (NPR and SPR) directly affect FTV performance. Conventionally, FTV performance evaluated by the common method using thrust pitching angle is highly dependent on the location of evaluation. Hence, in this study, we show that the thrust pitching moment, a parameter which is independent of the location, is the appropriate figure of merit to evaluate the performance of FTV systems.

  2. Post-burnout thrust measurements

    Science.gov (United States)

    McKenna, E. F.; Smith, H. T.

    1980-06-01

    Research was conducted into the problems of avoiding collision between separated payloads and spent rocket motors due to post burnout thrust, and the problem of contamination of scientific instrumentation due to outgassing of the smoldering insulation. The post burnout thrust was measured using a payload instrument module separated from an instrumented Black Brant VC Rocket in the exoatmosphere. In addition to measuring acceleration and velocities the spent motor was observed by a TV camera on board the command attitude controlled payload module. Analysis shows that the payload separated cleanly from the vehicle at a relative separation velocity of 0.69 m/sec, however the residual thrust of the spent motor overcame this differential, catching up to the payload 37 sec after separation and continuing on a parallel velocity vector at about 1.03 m/sec.

  3. More than a checklist: a realist evaluation of supervision of mid-level health workers in rural Guatemala.

    Science.gov (United States)

    Hernández, Alison R; Hurtig, Anna-Karin; Dahlblom, Kjerstin; San Sebastián, Miguel

    2014-03-06

    Mid-level health workers (MLHWs) form the front-line of service delivery in many low- and middle-income countries. Supervision is a critical institutional intervention linking their work to the health system, and it consists of activities intended to support health workers' motivation and enable them to perform. However its impact depends not only on the frequency of these activities but also how they are carried out and received. This study aims to deepen understanding of the mechanisms through which supervision activities support the performance of auxiliary nurses, a cadre of MLHWs, in rural Guatemala. A multiple case study was conducted to examine the operation of supervision of five health posts using a realist evaluation approach. A program theory was formulated describing local understanding of how supervision activities are intended to work. Data was collected through interviews and document review to test the theory. Analysis focused on comparison of activities, outcomes, mechanisms and the influence of context across cases, leading to revision of the program theory. The supervisor's orientation was identified as the main mechanism contributing to variation observed in activities and their outcomes. Managerial control was the dominant orientation, reflecting the influence of standardized performance criteria and institutional culture. Humanized support was present in one case where the auxiliary nurse was motivated by the sense that the full scope of her work was valued. This orientation reflected the supervisor's integration of her professional identity as a nurse. The nature of the support health workers received was shaped by supervisors' orientation, and in this study, nursing principles were central to humanized support. Efforts to strengthen the support that supervision provides to MLHWs should promote professional ethos as a means of developing shared performance goals and orient supervisors to a more holistic view of the health worker and their

  4. In the Middle: Work-Life Integration Experiences of Mid-Level Women Leaders in a Rural Community College System in the Northeastern United States

    Science.gov (United States)

    McGill-O'Rourke, Andrea

    2012-01-01

    Research indicates that work-life integration is linked with career satisfaction for women administrators in higher education. This study focuses on mid-level women leaders who are an essential component of higher education organizations. Employing a qualitative design that drew upon phenomenological methods, I explored the work-life integration…

  5. Training-Induced Recovery of Low-Level Vision Followed by Mid-Level Perceptual Improvements in Developmental Object and Face Agnosia

    Science.gov (United States)

    Lev, Maria; Gilaie-Dotan, Sharon; Gotthilf-Nezri, Dana; Yehezkel, Oren; Brooks, Joseph L.; Perry, Anat; Bentin, Shlomo; Bonneh, Yoram; Polat, Uri

    2015-01-01

    Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and object agnosia. Yet it is unclear whether training during adulthood, at a post-developmental…

  6. Training-Induced Recovery of Low-Level Vision Followed by Mid-Level Perceptual Improvements in Developmental Object and Face Agnosia

    Science.gov (United States)

    Lev, Maria; Gilaie-Dotan, Sharon; Gotthilf-Nezri, Dana; Yehezkel, Oren; Brooks, Joseph L.; Perry, Anat; Bentin, Shlomo; Bonneh, Yoram; Polat, Uri

    2015-01-01

    Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and object agnosia. Yet it is unclear whether training during adulthood, at a post-developmental…

  7. Another Look at Rocket Thrust

    Science.gov (United States)

    Hester, Brooke; Burris, Jennifer

    2012-01-01

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

  8. Another Look at Rocket Thrust

    Science.gov (United States)

    Hester, Brooke; Burris, Jennifer

    2012-01-01

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

  9. District health manager and mid-level provider perceptions of practice environments in acute obstetric settings in Tanzania: a mixed-method study.

    Science.gov (United States)

    Ng'ang'a, Njoki; Byrne, Mary Woods; Kruk, Margaret E; Shemdoe, Aloisia; de Pinho, Helen

    2016-08-08

    In sub-Saharan Africa, the capacity of human resources for health (HRH) managers to create positive practice environments that enable motivated, productive, and high-performing HRH is weak. We implemented a unique approach to examining HRH management practices by comparing perspectives offered by mid-level providers (MLPs) of emergency obstetric care (EmOC) in Tanzania to those presented by local health authorities, known as council health management teams (CHMTs). This study was guided by the basic strategic human resources management (SHRM) component model. A convergent mixed-method design was utilized to assess qualitative and quantitative data from the Health Systems Strengthening for Equity: The Power and Potential of Mid-Level Providers project. Survey data was obtained from 837 mid-level providers, 83 of whom participated in a critical incident interview whose aim was to elicit negative events in the practice environment that induced intention to leave their job. HRH management practices were assessed quantitatively in 48 districts with 37 members of CHMTs participating in semi-structured interviews. The eight human resources management practices enumerated in the basic SHRM component model were implemented unevenly. On the one hand, members of CHMTs and mid-level providers agreed that there were severe shortages of health workers, deficient salaries, and an overwhelming workload. On the other hand, members of CHMTs and mid-level providers differed in their perspectives on rewards and allocation of opportunities for in-service training. Although written standards of performance and supervision requirements were available in most districts, they did not reflect actual duties. Members of CHMTs reported high levels of autonomy in key HRH management practices, but mid-level providers disputed the degree to which the real situation on the ground was factored into job-related decision-making by CHMTs. The incongruence in perspectives offered by members of CHMTs

  10. Auditory intensity discrimination as a function of level-rove and tone duration in normal-hearing and impaired subjects: the "mid-level hump" revisited.

    Science.gov (United States)

    Pienkowski, Martin; Hagerman, Bjorn

    2009-07-01

    The just-noticeable difference (DeltaI) in the intensity (I) of sound is typically reported to be a constant or a slightly decreasing ratio of the baseline intensity (known as Weber's law, and the "near-miss to Weber's law", respectively). However, in the relatively few studies on the intensity discrimination of very brief sounds, DeltaI/I is usually found to be non-monotonic, with poorest discrimination in the middle of the auditory dynamic range. Here, it is demonstrated that this "severe departure from Weber's law" or "mid-level hump" is not merely a phenomenon of short-duration sounds. In normal-hearing subjects (n=8), the near-miss to Weber's law that is observed with the discrimination of 300 ms-long, 4 kHz tones, gives way to a significant mid-level hump if tone intensities are not fixed over a great many trials (as is standard practice) but are instead randomly roved, trial-to-trial, over a wide intensity range. This was not the case in subjects with mild to moderate hearing impairment (n=4). Furthermore, in the discrimination of widely-roved, 4 ms-long, 4 kHz tone bursts, the performance of normal-hearing subjects did not significantly worsen at mid-levels compared to the unroved condition, unlike what was found with the 300 ms-long tones. It is suggested that mid-level humps could simply be the product of the well-known mid-level compressive nonlinearity in cochlear mechanics. We further suggest that the hump is eliminated, and the near-miss to Weber's law is produced, by a more central mechanism such as the recently reported "adaptation to sound-level statistics", which is bypassed during wide-range roving and possibly when sound durations are brief.

  11. High Thrust-Density Electrostaic Engines Project

    Data.gov (United States)

    National Aeronautics and Space Administration — These issues are addressable by: increasing the thrust, power, and thrust-to-power ratio capability of EP systems; reducing the non-recurring engineering systems...

  12. Summarization on variable liquid thrust rocket engines

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The technology actuality and development trend of variable thrust rocket engines at home and abroad are summarized. Key technologies of developing variable thrust rocket engines are analyzed. Development advices on developing variable thrust rocket engines that are adapted to the situation of our country are brought forward.

  13. Nonlinear dynamics of a vectored thrust aircraft

    DEFF Research Database (Denmark)

    Sørensen, C.B; Mosekilde, Erik

    1996-01-01

    With realistic relations for the aerodynamic coefficients, numerical simulations are applied to study the longitudional dynamics of a thrust vectored aircraft. As function of the thrust magnitude and the thrust vectoring angle the equilibrium state exhibits two saddle-node bifurcations and three...

  14. Nonlinear dynamics of a vectored thrust aircraft

    DEFF Research Database (Denmark)

    Sørensen, C.B; Mosekilde, Erik

    1996-01-01

    With realistic relations for the aerodynamic coefficients, numerical simulations are applied to study the longitudional dynamics of a thrust vectored aircraft. As function of the thrust magnitude and the thrust vectoring angle the equilibrium state exhibits two saddle-node bifurcations and three ...

  15. Reflections of Turkish accounting and financial reporting standards on vocational school students: A research on comparing perceptions of intermediate and mid-level accounting professional candidates

    Directory of Open Access Journals (Sweden)

    Seldüz Hakan

    2016-01-01

    Full Text Available This research aims to compare the perceptions of intermediate and mid-level accounting professional candidates on accounting and financial reporting standards. A significant part of accounting process is carried out by vocational school graduate intermediate and mid-level accounting professionals. However, it can be claimed that adequate education about accounting and financial reporting standards isn’t given in vocational schools although these standards structure the whole accounting process. A survey is conducted over students of the related vocational school in Aksaray University. The results indicate no significant difference on students’ perceptions in terms of their school year, high school type, job or internship experience and intention to perform the profession after graduation. These results can be traced to inadequacy of present curriculums and internship programs which can’t create a difference. Based on the results, the content of internship applications is rearranged and an optional subject named as “Accounting and Reporting Standards” is established.

  16. Trabajadores de salud de nivel intermedio: un recurso prometedor Mid-level health providers: a promising resource

    Directory of Open Access Journals (Sweden)

    Andrew Brown

    2011-06-01

    Full Text Available Los trabajadores de salud de nivel intermedio (TSNI son trabajadores capacitados en una institución de educación superior durante al menos dos a tres años, quienes son autorizados y regulados para trabajar de forma autónoma para el diagnóstico, control y tratamiento de dolencias, enfermedades y discapacidades, así como participar en la prevención y promoción de la salud. Su papel se ha ampliado progresivamente y ha recibido atención en particular en países de ingresos bajos y medios, como parte de una estrategia para superar los desafíos del personal sanitario, mejorar el acceso a servicios básicos de salud y lograr objetivos relacionados con los Objetivos del Desarrollo del Milenio. La evidencia, aunque limitada e imperfecta, muestra que donde los TSNI están debidamente capacitados, apoyados y coherentemente integrados en el sistema de salud, tienen el potencial para mejorar la distribución de los trabajadores de la salud y el acceso equitativo a los servicios de salud, manteniendo -si no sobrepasando- los estándares de calidad comparables a los servicios prestados por el personal médico. Sin embargo, existen desafíos importantes en términos de la marginación y el limitado apoyo a la gestión de los TSNI en los sistemas de salud. La expansión de los TSNI debe tener prioridad entre las opciones de política consideradas por países que enfrentan problemas de escasez y desigualdad en la distribución de recursos humanos. Una mejor educación, supervisión, administración y regulación de las prácticas y la integración en el sistema de salud tienen el potencial de maximizar los beneficios de la utilización de este personal.Mid-level health providers (MLP are health workers trained at a higher education institution for at least a total of 2-3 years, and authorized and regulated to work autonomously to diagnose, manage and treat illness, disease and impairments, as well as engage in preventive and promotive care. Their role

  17. Improving access to oral health care services among underserved populations in the U.S.: is there a role for mid-level dental providers?

    Science.gov (United States)

    Shaefer, H Luke; Miller, Matthew

    2011-08-01

    Nearly one-third of U.S. citizens lack access to basic preventive and primary oral health care services, which is primarily the result of the high costs of care and the uneven geographic distribution of dental providers. This article examines the case for and against one possible solution to address these barriers to oral health care: the introduction of a mid-level dental provider (MDP) position within the dental field.

  18. Training-induced recovery of low-level vision followed by mid-level perceptual improvements in developmental object and face agnosia.

    Science.gov (United States)

    Lev, Maria; Gilaie-Dotan, Sharon; Gotthilf-Nezri, Dana; Yehezkel, Oren; Brooks, Joseph L; Perry, Anat; Bentin, Shlomo; Bonneh, Yoram; Polat, Uri

    2015-01-01

    Long-term deprivation of normal visual inputs can cause perceptual impairments at various levels of visual function, from basic visual acuity deficits, through mid-level deficits such as contour integration and motion coherence, to high-level face and object agnosia. Yet it is unclear whether training during adulthood, at a post-developmental stage of the adult visual system, can overcome such developmental impairments. Here, we visually trained LG, a developmental object and face agnosic individual. Prior to training, at the age of 20, LG's basic and mid-level visual functions such as visual acuity, crowding effects, and contour integration were underdeveloped relative to normal adult vision, corresponding to or poorer than those of 5-6 year olds (Gilaie-Dotan, Perry, Bonneh, Malach & Bentin, 2009). Intensive visual training, based on lateral interactions, was applied for a period of 9 months. LG's directly trained but also untrained visual functions such as visual acuity, crowding, binocular stereopsis and also mid-level contour integration improved significantly and reached near-age-level performance, with long-term (over 4 years) persistence. Moreover, mid-level functions that were tested post-training were found to be normal in LG. Some possible subtle improvement was observed in LG's higher-order visual functions such as object recognition and part integration, while LG's face perception skills have not improved thus far. These results suggest that corrective training at a post-developmental stage, even in the adult visual system, can prove effective, and its enduring effects are the basis for a revival of a developmental cascade that can lead to reduced perceptual impairments.

  19. A Markov model assessing the impact on primary care practice revenues and patient's health when using mid-level providers, lesson learned from the United Kingdom.

    Science.gov (United States)

    Hill, Harry; Macey, Richard; Brocklehurst, Paul

    2017-03-08

    To evaluate the cost-effectiveness of using mid-level providers for dental "check-up" examinations and the treatment of caries in different NHS settings in the United Kingdom. Mid-level providers are a broad category that describes non-dentist members of dental teams. This study focused on the potential use of Dental Hygiene Therapists undertaking dental "check-up" examinations and simple restorative treatment, instead of dentists. A Markov model was used to construct the natural history of caries development in adults that visit a dental practice every six months over a five-year period. Three cost perspectives are taken: those borne to dental healthcare providers in England and Wales, Northern Ireland and Scotland. These represent three separate forms of retrospective payment system that are currently in use in the United Kingdom. The cost outcome was the average amount of retained practice earnings required to provide healthcare per patient visit. The health outcome was the average length of time in a cavity-free state and the cost-effectiveness outcome was incremental cost for six months in a cavity-free state. No statistical difference was found between dentists and mid-level providers in the length of time in a cavity-free state but the use of the latter saved money in all three NHS health system jurisdictions. This ranged from £7.85 (England and Wales) to £9.16 (Northern Ireland) per patient visit ($10.20 to $11.90, respectively) meaning the incremental cost for six month in a cavity-free state ranged from £261.67 ($339.93) in England and Wales to £305.33 ($369.68) in Northern Ireland. Further, changes in baseline assumptions and parameter values did not change mid-level providers being the dominant service intervention. In a time of limited funds for dental services, these results suggest that resources in public funded systems could be saved using mid-level providers in dental practices, without any health risk to patients or capital investment.

  20. Modeling post-fire sediment yield based on two burn scenarios at the Sooke Lake Reservoir, BC, Canada

    Science.gov (United States)

    Dobre, Mariana; Elliot, William J.; Brooks, Erin S.; Smith, Tim

    2016-04-01

    Wildfires can have major adverse effects on municipal water sources. Local governments need methods to evaluate fire risk and to develop mitigation procedures. The Sooke Lake Reservoir is the primary source of water for the city of Victoria, BC and the concern is that sediment delivered from upland burned areas could have a detrimental impact on the reservoir and the water supply. We conducted a sediment delivery modeling pilot study on a portion of the Sooke Lake Reservoir (specifically, the Trestle Creek Management Unit (TCMU)) to evaluate the potential impacts of wildfire on sediment delivery from hillslopes and sub-catchments. We used a process-based hydrologic and soil erosion model called Water Erosion Prediction Project geospatial interface, GeoWEPP, to predict the sediment delivery from specific return period design storms for two burn severity scenarios: real (low-intensity burn severity) and worst (high-intensity burn severity) case scenarios. The GeoWEPP model allows users to simulate streamflow and erosion from hillslope polygons within a watershed. The model requires information on the topographic, soil and vegetative characteristics for each hillslope and a weather file. WEPP default values and several assumptions were necessary to apply the model where data were missing. Based on a 10-m DEM we delineated 16 watersheds within the TCMU area. A long term 100-year daily climate file was generated for this analysis using the CLIGEN model based on the historical observations recorded at Concrete, WA in United States, and adjusted for observed monthly precipitation observed in the Sooke Basin. We ran 100-year simulations and calculated yearly and event-based return periods (for 2, 5, 10, 20, 25, and 50 years) for each of the 16 watersheds. Overall, WEPP simulations indicate that the storms that are most likely to produce the greatest runoff and sediment load in these coastal, maritime climates with relatively low rainfall intensities are likely to occur in

  1. Dielectric Barrier Discharge (DBD) Plasma Actuators Thrust-Measurement Methodology Incorporating New Anti-Thrust Hypothesis

    Science.gov (United States)

    Ashpis, David E.; Laun, Matthew C.

    2014-01-01

    We discuss thrust measurements of Dielectric Barrier Discharge (DBD) plasma actuators devices used for aerodynamic active flow control. After a review of our experience with conventional thrust measurement and significant non-repeatability of the results, we devised a suspended actuator test setup, and now present a methodology of thrust measurements with decreased uncertainty. The methodology consists of frequency scans at constant voltages. The procedure consists of increasing the frequency in a step-wise fashion from several Hz to the maximum frequency of several kHz, followed by frequency decrease back down to the start frequency of several Hz. This sequence is performed first at the highest voltage of interest, then repeated at lower voltages. The data in the descending frequency direction is more consistent and selected for reporting. Sample results show strong dependence of thrust on humidity which also affects the consistency and fluctuations of the measurements. We also observed negative values of thrust or "anti-thrust", at low frequencies between 4 Hz and up to 64 Hz. The anti-thrust is proportional to the mean-squared voltage and is frequency independent. Departures from the parabolic anti-thrust curve are correlated with appearance of visible plasma discharges. We propose the anti-thrust hypothesis. It states that the measured thrust is a sum of plasma thrust and anti-thrust, and assumes that the anti-thrust exists at all frequencies and voltages. The anti-thrust depends on actuator geometry and materials and on the test installation. It enables the separation of the plasma thrust from the measured total thrust. This approach enables more meaningful comparisons between actuators at different installations and laboratories. The dependence on test installation was validated by surrounding the actuator with a large diameter, grounded, metal sleeve.

  2. Physician substitution by mid-level providers in primary healthcare for older people and long-term care facilities: protocol for a systematic literature review.

    Science.gov (United States)

    Lovink, Marleen H; Persoon, Anke; van Vught, Anneke J A H; Koopmans, Raymond T C M; Schoonhoven, Lisette; Laurant, Miranda G H

    2015-12-01

    This protocol describes a systematic review that evaluates the effects of physician substitution by mid-level providers (nurse practitioners, physician assistants or nurses) in primary healthcare for older people and long-term care facilities. The secondary aim is to describe facilitators and barriers to the implementation of physician substitution in these settings. Healthcare for older people is undergoing major changes, due to population ageing and reforms that shift care to the community. Besides, relatively few medical students are pursuing careers in healthcare for older people. Innovative solutions are needed to guarantee the quality of healthcare and to contain costs. A solution might be shifting care from physicians to mid-level providers. To date, no systematic review on this topic exits to guide policymaking. A quantitative systematic literature review using Cochrane methods. The following databases will be searched for original research studies that quantitatively compare care provided by a physician to the same care provided by a mid-level provider: PubMed, EMBASE, CINAHL, PsycINFO, CENTRAL and Web of Science. Study selection, data extraction and quality appraisal will be conducted independently by two reviewers. Data synthesis will consist of a qualitative analysis of the data. Funding of the review was confirmed in August 2013 by the Ministry of Health, Welfare and Sport of the Netherlands. This review will contribute to the knowledge on effects of physician substitution in healthcare for older people and factors that influence the outcomes. This knowledge will guide professionals and policy administrators in their decisions to optimize healthcare for older people. © 2015 John Wiley & Sons Ltd.

  3. Measuring Model Rocket Engine Thrust Curves

    Science.gov (United States)

    Penn, Kim; Slaton, William V.

    2010-01-01

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

  4. Mu rhythm desynchronization by tongue thrust observation.

    Science.gov (United States)

    Sakihara, Kotoe; Inagaki, Masumi

    2015-01-01

    We aimed to investigate the mu rhythm in the sensorimotor area during tongue thrust observation and to obtain an answer to the question as to how subtle non-verbal orofacial movement observation activates the sensorimotor area. Ten healthy volunteers performed finger tap execution, tongue thrust execution, and tongue thrust observation. The electroencephalogram (EEG) was recorded from 128 electrodes placed on the scalp, and regions of interest were set at sensorimotor areas. The event-related desynchronization (ERD) and event-related synchronization (ERS) for the mu rhythm (8-13 Hz) and beta (13-25 Hz) bands were measured. Tongue thrust observation induced mu rhythm ERD, and the ERD was detected at the left hemisphere regardless whether the observed tongue thrust was toward the left or right. Mu rhythm ERD was also recorded during tongue thrust execution. However, temporal analysis revealed that the ERD associated with tongue thrust observation preceded that associated with execution by approximately 2 s. Tongue thrust observation induces mu rhythm ERD in sensorimotor cortex with left hemispheric dominance.

  5. Measuring Model Rocket Engine Thrust Curves

    Science.gov (United States)

    Penn, Kim; Slaton, William V.

    2010-01-01

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

  6. Benchmarking numerical models of brittle thrust wedges

    Science.gov (United States)

    Buiter, Susanne J. H.; Schreurs, Guido; Albertz, Markus; Gerya, Taras V.; Kaus, Boris; Landry, Walter; le Pourhiet, Laetitia; Mishin, Yury; Egholm, David L.; Cooke, Michele; Maillot, Bertrand; Thieulot, Cedric; Crook, Tony; May, Dave; Souloumiac, Pauline; Beaumont, Christopher

    2016-11-01

    We report quantitative results from three brittle thrust wedge experiments, comparing numerical results directly with each other and with corresponding analogue results. We first test whether the participating codes reproduce predictions from analytical critical taper theory. Eleven codes pass the stable wedge test, showing negligible internal deformation and maintaining the initial surface slope upon horizontal translation over a frictional interface. Eight codes participated in the unstable wedge test that examines the evolution of a wedge by thrust formation from a subcritical state to the critical taper geometry. The critical taper is recovered, but the models show two deformation modes characterised by either mainly forward dipping thrusts or a series of thrust pop-ups. We speculate that the two modes are caused by differences in effective basal boundary friction related to different algorithms for modelling boundary friction. The third experiment examines stacking of forward thrusts that are translated upward along a backward thrust. The results of the seven codes that run this experiment show variability in deformation style, number of thrusts, thrust dip angles and surface slope. Overall, our experiments show that numerical models run with different numerical techniques can successfully simulate laboratory brittle thrust wedge models at the cm-scale. In more detail, however, we find that it is challenging to reproduce sandbox-type setups numerically, because of frictional boundary conditions and velocity discontinuities. We recommend that future numerical-analogue comparisons use simple boundary conditions and that the numerical Earth Science community defines a plasticity test to resolve the variability in model shear zones.

  7. Collar nut and thrust ring

    Science.gov (United States)

    Lowery, Guy B.

    1991-01-01

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

  8. High Performance Methane Thrust Chamber (HPMTC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a High-Performance Methane Thrust Chamber (HPMRE) to meet the demands of advanced chemical propulsion systems for deep-space mission...

  9. Combination radial and thrust magnetic bearing

    Science.gov (United States)

    Blumenstock, Kenneth A. (Inventor)

    2002-01-01

    A combination radial and thrust magnetic bearing is disclosed that allows for both radial and thrust axes control of an associated shaft. The combination radial and thrust magnetic bearing comprises a rotor and a stator. The rotor comprises a shaft, and first and second rotor pairs each having respective rotor elements. The stator comprises first and second stator elements and a magnet-sensor disk. In one embodiment, each stator element has a plurality of split-poles and a corresponding plurality of radial force coils and, in another embodiment, each stator element does not require thrust force coils, and radial force coils are replaced by double the plurality of coils serving as an outer member of each split-pole half.

  10. 14 CFR 33.97 - Thrust reversers.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.97 Thrust reversers. (a) If the engine incorporates a reverser, the endurance calibration, operation, and vibration tests prescribed...

  11. Benchmarking numerical models of brittle thrust wedges

    NARCIS (Netherlands)

    Buiter, Susanne J H; Schreurs, Guido; Albertz, Markus; Gerya, Taras V.; Kaus, Boris; Landry, Walter; le Pourhiet, Laetitia; Mishin, Yury; Egholm, David L.; Cooke, Michele; Maillot, Bertrand; Thieulot, Cedric|info:eu-repo/dai/nl/270177493; Crook, Tony; May, Dave; Souloumiac, Pauline; Beaumont, Christopher

    2016-01-01

    We report quantitative results from three brittle thrust wedge experiments, comparing numerical results directly with each other and with corresponding analogue results. We first test whether the participating codes reproduce predictions from analytical critical taper theory. Eleven codes pass the

  12. Multiphysics Nuclear Thermal Rocket Thrust Chamber Analysis

    Science.gov (United States)

    Wang, Ten-See

    2005-01-01

    The objective of this effort is t o develop an efficient and accurate thermo-fluid computational methodology to predict environments for hypothetical thrust chamber design and analysis. The current task scope is to perform multidimensional, multiphysics analysis of thrust performance and heat transfer analysis for a hypothetical solid-core, nuclear thermal engine including thrust chamber and nozzle. The multiphysics aspects of the model include: real fluid dynamics, chemical reactivity, turbulent flow, and conjugate heat transfer. The model will be designed to identify thermal, fluid, and hydrogen environments in all flow paths and materials. This model would then be used to perform non- nuclear reproduction of the flow element failures demonstrated in the Rover/NERVA testing, investigate performance of specific configurations and assess potential issues and enhancements. A two-pronged approach will be employed in this effort: a detailed analysis of a multi-channel, flow-element, and global modeling of the entire thrust chamber assembly with a porosity modeling technique. It is expected that the detailed analysis of a single flow element would provide detailed fluid, thermal, and hydrogen environments for stress analysis, while the global thrust chamber assembly analysis would promote understanding of the effects of hydrogen dissociation and heat transfer on thrust performance. These modeling activities will be validated as much as possible by testing performed by other related efforts.

  13. Modes of thrust generation in flying animals

    Science.gov (United States)

    Luo, Haoxiang; Song, Jialei; Tobalske, Bret; Luo Team; Tobalske Team

    2016-11-01

    For flying animals in forward flight, thrust is usually much smaller as compared with weight support and has not been given the same amount of attention. Several modes of thrust generation are discussed in this presentation. For insects performing slow flight that is characterized by low advance ratios (i.e., the ratio between flight speed and wing speed), thrust is usually generated by a "backward flick" mode, in which the wings moves upward and backward at a faster speed than the flight speed. Paddling mode is another mode used by some insects like fruit flies who row their wings backward during upstroke like paddles (Ristroph et al., PRL, 2011). Birds wings have high advance ratios and produce thrust during downstroke by directing aerodynamic lift forward. At intermediate advance ratios around one (e.g., hummingbirds and bats), the animal wings generate thrust during both downstroke and upstroke, and thrust generation during upstroke may come at cost of negative weight support. These conclusions are supported by previous experiment studies of insects, birds, and bats, as well as our recent computational modeling of hummingbirds. Supported by the NSF.

  14. 14 CFR 33.79 - Fuel burning thrust augmentor.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel burning thrust augmentor. 33.79... thrust augmentor. Each fuel burning thrust augmentor, including the nozzle, must— (a) Provide cutoff of the fuel burning thrust augmentor; (b) Permit on-off cycling; (c) Be controllable within the intended...

  15. Thrust distribution for attitude control in a variable thrust propulsion system with four ACS nozzles

    Science.gov (United States)

    Lim, Yeerang; Lee, Wonsuk; Bang, Hyochoong; Lee, Hosung

    2017-04-01

    A thrust distribution approach is proposed in this paper for a variable thrust solid propulsion system with an attitude control system (ACS) that uses a reduced number of nozzles for a three-axis attitude maneuver. Although a conventional variable thrust solid propulsion system needs six ACS nozzles, this paper proposes a thrust system with four ACS nozzles to reduce the complexity and mass of the system. The performance of the new system was analyzed with numerical simulations, and the results show that the performance of the system with four ACS nozzles was similar to the original system while the mass of the whole system was simultaneously reduced. Moreover, a feasibility analysis was performed to determine whether a thrust system with three ACS nozzles is possible.

  16. Earthquake Surface Rupture of the Salt Range Thrust at the Himalayan Thrust Front in Pakistan

    Science.gov (United States)

    Meigs, A.; Yule, J. D.; Madden, C.; Yeats, R.; Hussain, A.; Akhtar, S. S.; Latif, A.; Waliullah, A.; Ashraf, M.; Ramzan, S.; Dasti, N.

    2007-12-01

    Considerable evidence from Nepal and India now indicates that the basal detachment of the Himalaya produces great earthquakes that result in large coseismic displacements at the thrust front in India and Nepal (the Main Frontal thrust). In contrast, knowledge of the earthquake potential of the Salt Range thrust in Pakistan (SRT) is virtually absent. It has been clear since the publication of the Salt Range maps of Gee (1989) that the SRT deforms young surficial deposits and is an active fault. What remains uncertain is whether surface rupturing events occur on the SRT, with what frequency those events occur, and what is the size of the associated earthquakes. In a field reconnaissance of the SRT in Spring, 2007, we were able to confirm that this thrust is an active fault, and we discovered numerous localities where the fault nearly reaches the surface, cutting all but the youngest few meters of colluvial deposits. Whereas our observations suggest that surface rupturing events occur on the SRT, a number of characteristics of the Pakistani Himalaya suggests the earthquake behavior of the basal detachment and thrust front may be substantially different than it is in India and Nepal to the southeast. Key differences include an uncertain, but lower, convergence rate at the thrust front (5 to 13 mm/yr), a low tapered thrust wedge, and localization of the basal detachment in a weak evaporite unit. In this sense, the front of the Zagros fold-and-thrust belt in Iran may be a more appropriate analog for the thrust front in Pakistan than the Himalayan thrust front to the southeast. Future mapping of deformed geomorphic surfaces and paleoseismic trenching along the SRT will provide the first direct evidence of the earthquake potential and recurrence of plate- boundary earthquakes in Pakistan. This knowledge is critical for hazard assessment in north-central Pakistan where more than 7 million people are likely to be affected by a great earthquake on the plate boundary.

  17. Pulsed thrust measurements using electromagnetic calibration techniques

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-15

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

  18. Status of Low Thrust Work at JSC

    Science.gov (United States)

    Condon, Gerald L.

    2004-01-01

    High performance low thrust (solar electric, nuclear electric, variable specific impulse magnetoplasma rocket) propulsion offers a significant benefit to NASA missions beyond low Earth orbit. As NASA (e.g., Prometheus Project) endeavors to develop these propulsion systems and associated power supplies, it becomes necessary to develop a refined trajectory design capability that will allow engineers to develop future robotic and human mission designs that take advantage of this new technology. This ongoing work addresses development of a trajectory design and optimization tool for assessing low thrust (and other types) trajectories. This work targets to advance the state of the art, enable future NASA missions, enable science drivers, and enhance education. This presentation provides a summary of the low thrust-related JSC activities under the ISP program and specifically, provides a look at a new release of a multi-gravity, multispacecraft trajectory optimization tool (Copernicus) along with analysis performed using this tool over the past year.

  19. Role of wing morphing in thrust generation

    Directory of Open Access Journals (Sweden)

    Mehdi Ghommem

    2014-01-01

    Full Text Available In this paper, we investigate the role of morphing on flight dynamics of two birds by simulating the flow over rigid and morphing wings that have the characteristics of two different birds, namely the Giant Petrel and Dove Prion. The simulation of a flapping rigid wing shows that the root of the wing should be placed at a specific angle of attack in order to generate enough lift to balance the weight of the bird. However, in this case the generated thrust is either very small, or even negative, depending on the wing shape. Further, results show that morphing of the wing enables a significant increase in the thrust and propulsive efficiency. This indicates that the birds actually utilize some sort of active wing twisting and bending to produce enough thrust. This study should facilitate better guidance for the design of flapping air vehicles.

  20. A microNewton thrust stand for average thrust measurement of pulsed microthruster.

    Science.gov (United States)

    Zhou, Wei-Jing; Hong, Yan-Ji; Chang, Hao

    2013-12-01

    A torsional thrust stand has been developed for the study of the average thrust for microNewton pulsed thrusters. The main body of the thrust stand mainly consists of a torsional balance, a pair of flexural pivots, a capacitive displacement sensor, a calibration assembly, and an eddy current damper. The behavior of the stand was thoroughly studied. The principle of thrust measurement was analyzed. The average thrust is determined as a function of the average equilibrium angle displacement of the balance and the spring stiffness. The thrust stand has a load capacity up to 10 kg, and it can theoretically measure the force up to 609.6 μN with a resolution of 24.4 nN. The static calibrations were performed based on the calibration assembly composed of the multiturn coil and the permanent magnet. The calibration results demonstrated good repeatability (less than 0.68% FSO) and good linearity (less than 0.88% FSO). The assembly of the multiturn coil and the permanent magnet was also used as an exciter to simulate the microthruster to further research the performance of the thrust stand. Three sets of force pulses at 17, 33.5, and 55 Hz with the same amplitude and pulse width were tested. The repeatability error at each frequency was 7.04%, 1.78%, and 5.08%, respectively.

  1. A microNewton thrust stand for average thrust measurement of pulsed microthruster

    Science.gov (United States)

    Zhou, Wei-Jing; Hong, Yan-Ji; Chang, Hao

    2013-12-01

    A torsional thrust stand has been developed for the study of the average thrust for microNewton pulsed thrusters. The main body of the thrust stand mainly consists of a torsional balance, a pair of flexural pivots, a capacitive displacement sensor, a calibration assembly, and an eddy current damper. The behavior of the stand was thoroughly studied. The principle of thrust measurement was analyzed. The average thrust is determined as a function of the average equilibrium angle displacement of the balance and the spring stiffness. The thrust stand has a load capacity up to 10 kg, and it can theoretically measure the force up to 609.6 μN with a resolution of 24.4 nN. The static calibrations were performed based on the calibration assembly composed of the multiturn coil and the permanent magnet. The calibration results demonstrated good repeatability (less than 0.68% FSO) and good linearity (less than 0.88% FSO). The assembly of the multiturn coil and the permanent magnet was also used as an exciter to simulate the microthruster to further research the performance of the thrust stand. Three sets of force pulses at 17, 33.5, and 55 Hz with the same amplitude and pulse width were tested. The repeatability error at each frequency was 7.04%, 1.78%, and 5.08%, respectively.

  2. Benchmarking numerical models of brittle thrust wedges

    NARCIS (Netherlands)

    Buiter, Susanne J H; Schreurs, Guido; Albertz, Markus; Gerya, Taras V.; Kaus, Boris; Landry, Walter; le Pourhiet, Laetitia; Mishin, Yury; Egholm, David L.; Cooke, Michele; Maillot, Bertrand; Thieulot, Cedric; Crook, Tony; May, Dave; Souloumiac, Pauline; Beaumont, Christopher

    2016-01-01

    We report quantitative results from three brittle thrust wedge experiments, comparing numerical results directly with each other and with corresponding analogue results. We first test whether the participating codes reproduce predictions from analytical critical taper theory. Eleven codes pass the s

  3. Reverse Core Engine with Thrust Reverser

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2017-01-01

    An engine system has a gas generator, a bi-fi wall surrounding at least a portion of the gas generator, a casing surrounding a fan, and the casing having first and second thrust reverser doors which in a deployed position abut each other and the bi-fi wall.

  4. Mid-level Providers Working in a Low-acuity Area are More Productive than in a High-acuity Area.

    Science.gov (United States)

    Silberman, Michael; Jeanmonod, Donald; Hamden, Khalief; Reiter, Mark; Jeanmonod, Rebecca

    2013-11-01

    Mid-level providers (MLP) are extensively used in staffing emergency departments (ED). We sought to compare the productivity of MLPs staffing a low-acuity and high-acuity area of a community ED. This is a retrospective review of MLP productivity at a single center 42,000-volume community ED from July 2009 to September 2010. MLPs staffed day shifts (8AM-6PM or 10AM-10PM) in high- and low-acuity sections of the ED. We used two-tailed T-test to compare patients/hour, relative value units (RVUs)/hour, and RVUs/patient between the 2 MLP groups. We included 49 low-acuity and 55 high-acuity shifts in this study. During the study period, MLPs staffing low-acuity shifts treated a mean of 2.7 patients/hour (confidence interval [CI] +/- 0.23), while those staffing high-acuity shifts treated a mean of 1.56 patients/hour (CI +/- 0.14, p<0.0001). MLPs staffing low-acuity shifts generated a mean of 4.45 RVUs/hour (CI +/- 0.34) compared to 3.19 RVUs/hour (CI +/- 0.29) for those staffing high-acuity shifts (p<0.0001). MLPs staffing low-acuity shifts generated a mean of 1.68 RVUs/patient (CI +/- 0.06) while those staffing high-acuity shifts generated a mean RVUs/patient of 2.05 (CI +/- 0.09, p<0.0001). MLPs staffing a low-acuity area treated more patients/hour and generated more RVUs/hour than when staffing a high-acuity area.

  5. Mid-level Providers Working in a Low-acuity Area are More Productive than in a High-acuity Area

    Directory of Open Access Journals (Sweden)

    Silberman, Michael

    2013-11-01

    Full Text Available Introduction: Mid-level providers (MLP are extensively used in staffing emergency departments (ED. We sought to compare the productivity of MLPs staffing a low-acuity and high-acuity area of a community ED.Methods: This is a retrospective review of MLP productivity at a single center 42,000-volume community ED from July 2009 to September 2010. MLPs staffed day shifts (8AM-6PM or 10AM-10PM in high- and low-acuity sections of the ED. We used two-tailed T-test to compare patients/hour, relative value units (RVUs/hour, and RVUs/patient between the 2 MLP groups. Results: We included 49 low-acuity and 55 high-acuity shifts in this study. During the study period, MLPs staffing low-acuity shifts treated a mean of 2.7 patients/hour (confidence interval [CI] +/- 0.23, while those staffing high-acuity shifts treated a mean of 1.56 patients/hour (CI +/- 0.14, P < 0.0001. MLPs staffing low-acuity shifts generated a mean of 4.45 RVUs/hour (CI +/- 0.34 compared to 3.19 RVUs/hour (CI +/-0.29 for those staffing high-acuity shifts (P < 0.0001. MLPs staffing low-acuity shifts generated a mean of 1.68 RVUs/patient (CI +/- 0.06 while those staffing high-acuity shifts generated a mean RVUs/patient of 2.05 (CI +/- 0.09, P < 0.0001. Conclusion: MLPs staffing a low-acuity area treated more patients/hour and generated more RVUs/hour than when staffing a high-acuity area. [West J Emerg Med.2013;14(6:598–601.

  6. Mid-Level Healthcare Personnel Training: An Evaluation of the Revised, Nationally-Standardized, Pre-Service Curriculum for Clinical Officers in Mozambique

    Science.gov (United States)

    Feldacker, Caryl; Chicumbe, Sergio; Dgedge, Martinho; Augusto, Gerito; Cesar, Freide; Robertson, Molly; Mbofana, Francisco; O'Malley, Gabrielle

    2014-01-01

    Introduction Mozambique suffers from a critical shortage of healthcare workers. Mid-level healthcare workers, (Tecnicos de Medicina Geral (TMG)), in Mozambique require less money and time to train than physicians. From 2009–2010, the Mozambique Ministry of Health (MoH) and the International Training and Education Center for Health (I-TECH), University of Washington, Seattle, revised the TMG curriculum. To evaluate the effect of the curriculum revision, we used mixed methods to determine: 1) if TMGs meet the MoH's basic standards of clinical competency; and 2) do scores on measurements of clinical knowledge, physical exam, and clinical case scenarios differ by curriculum? Methods T-tests of differences in means examined differences in continuous score variables between curriculum groups. Univariate and multivariate linear regression models assess curriculum-related and demographic factors associated with assessment scores on each of the three evaluation methods at the pcurriculum, respectively. Mean scores at graduation of initial curriculum TMGs were 56.7%, 63.5%, and 49.1% on the clinical cases, knowledge test, and physical exam, respectively. Scores did not differ significantly from TMGs in the revised curriculum. Results from linear regression models find that training institute was the most significant predictor of TMG scores on both the clinical cases and physical exam. Conclusion TMGs trained in either curriculum may be inadequately prepared to provide quality care. Curriculum changes are a necessary, but insufficient, part of improving TMG knowledge and skills overall. A more comprehensive, multi-level approach to improving TMG training that includes post-graduation mentoring, strengthening the pre-service internship training, and greater resources for training institute faculty may result in improvements in TMG capacity and patient care over time. PMID:25068590

  7. Precise Thrust Actuation by a Micro RF Ion Engine Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek proposes to develop a radio-frequency discharge, gridded micro ion engine that produces 5N level of thrust precisely adjustable over a wide dynamic thrust...

  8. Thrust and Propulsive Efficiency from an Instructive Viewpoint

    Science.gov (United States)

    Kaufman, Richard D.

    2010-01-01

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

  9. Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate

    Directory of Open Access Journals (Sweden)

    William R. Reed

    2013-01-01

    Full Text Available High velocity low amplitude spinal manipulation (HVLA-SM is used frequently to treat musculoskeletal complaints. Little is known about the intervention’s biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150 ms suggesting the presence of a threshold value. Thrust velocities greater than 20–30 mm/s and thrust rates greater than 300 N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages.

  10. Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate.

    Science.gov (United States)

    Reed, William R; Cao, Dong-Yuan; Long, Cynthia R; Kawchuk, Gregory N; Pickar, Joel G

    2013-01-01

    High velocity low amplitude spinal manipulation (HVLA-SM) is used frequently to treat musculoskeletal complaints. Little is known about the intervention's biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150 ms suggesting the presence of a threshold value. Thrust velocities greater than 20-30 mm/s and thrust rates greater than 300 N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages.

  11. Thrust and Propulsive Efficiency from an Instructive Viewpoint

    Science.gov (United States)

    Kaufman, Richard D.

    2010-01-01

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

  12. 40Ar/39Ar dating of Daqingshan thrust

    Institute of Scientific and Technical Information of China (English)

    LIU Zhenghong; XU Zhongyuan; YANG Zhensheng

    2003-01-01

    The Daqingshan thrust system, to the south of the Shiguai Mesozoic basin, is a complex system of top-to- the-north thrusting tectonic sheets. The thrust system has a complicated evolution due to multi-stage thrusting. In order to date the thrusting events, syntectonic muscovite and biotite grains are respectively analyzed with normal 40Ar/39Ar dating and laser 40Ar/39Ar dating, which yield 2 isochron ages, i.e. 193.74 ± 3.88 Ma and 121.6 ± 1.6 Ma. These ages suggest that faults within the Daqingshan thrust system formed during 2 stages of thrusting, one the early Indosinian and the other the late Yanshanian. The isotopic dating is consistent with field geological relations. Indosinan deformation is evidenced by top-to-the-north thrusting, with the occurrence of a series of large-scale east-west trending thrust faults and folds, while the Yanshanian thrusting is characterized by top-to-the-NNW thrusting. It is superposed on and modifies early Indosinian thrust faults.

  13. NATURAL BARRIERS TARGETED THRUST FY 2004 PROJECTS

    Energy Technology Data Exchange (ETDEWEB)

    NA

    2005-07-27

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

  14. MATERIALS PERFORMANCE TARGETED THRUST FY 2004 PROJECTS

    Energy Technology Data Exchange (ETDEWEB)

    DOE

    2005-09-13

    The Yucca Mountain site was recommended by the President to be a geological repository for commercial spent nuclear fuel and high-level radioactive waste. The multi-barrier approach was adopted for assessing and predicting system behavior, including both natural barriers and engineered barriers. A major component of the long-term strategy for safe disposal of nuclear waste is first to completely isolate the radionuclides in waste packages for long times and then to greatly retard the egress and transport of radionuclides from penetrated packages. The goal of the Materials Performance Targeted Thrust program is to further enhance the understanding of the role of engineered barriers in waste isolation. In addition, the Thrust will explore technical enhancements and seek to offer improvements in materials costs and reliability.

  15. Benchmarking analogue models of brittle thrust wedges

    Science.gov (United States)

    Schreurs, Guido; Buiter, Susanne J. H.; Boutelier, Jennifer; Burberry, Caroline; Callot, Jean-Paul; Cavozzi, Cristian; Cerca, Mariano; Chen, Jian-Hong; Cristallini, Ernesto; Cruden, Alexander R.; Cruz, Leonardo; Daniel, Jean-Marc; Da Poian, Gabriela; Garcia, Victor H.; Gomes, Caroline J. S.; Grall, Céline; Guillot, Yannick; Guzmán, Cecilia; Hidayah, Triyani Nur; Hilley, George; Klinkmüller, Matthias; Koyi, Hemin A.; Lu, Chia-Yu; Maillot, Bertrand; Meriaux, Catherine; Nilfouroushan, Faramarz; Pan, Chang-Chih; Pillot, Daniel; Portillo, Rodrigo; Rosenau, Matthias; Schellart, Wouter P.; Schlische, Roy W.; Take, Andy; Vendeville, Bruno; Vergnaud, Marine; Vettori, Matteo; Wang, Shih-Hsien; Withjack, Martha O.; Yagupsky, Daniel; Yamada, Yasuhiro

    2016-11-01

    We performed a quantitative comparison of brittle thrust wedge experiments to evaluate the variability among analogue models and to appraise the reproducibility and limits of model interpretation. Fifteen analogue modeling laboratories participated in this benchmark initiative. Each laboratory received a shipment of the same type of quartz and corundum sand and all laboratories adhered to a stringent model building protocol and used the same type of foil to cover base and sidewalls of the sandbox. Sieve structure, sifting height, filling rate, and details on off-scraping of excess sand followed prescribed procedures. Our analogue benchmark shows that even for simple plane-strain experiments with prescribed stringent model construction techniques, quantitative model results show variability, most notably for surface slope, thrust spacing and number of forward and backthrusts. One of the sources of the variability in model results is related to slight variations in how sand is deposited in the sandbox. Small changes in sifting height, sifting rate, and scraping will result in slightly heterogeneous material bulk densities, which will affect the mechanical properties of the sand, and will result in lateral and vertical differences in peak and boundary friction angles, as well as cohesion values once the model is constructed. Initial variations in basal friction are inferred to play the most important role in causing model variability. Our comparison shows that the human factor plays a decisive role, and even when one modeler repeats the same experiment, quantitative model results still show variability. Our observations highlight the limits of up-scaling quantitative analogue model results to nature or for making comparisons with numerical models. The frictional behavior of sand is highly sensitive to small variations in material state or experimental set-up, and hence, it will remain difficult to scale quantitative results such as number of thrusts, thrust spacing

  16. Low Carbon Propulsion Strategic Thrust Overview

    Science.gov (United States)

    Dryer, Jay

    2014-01-01

    NASA is taking a leadership role with regard to developing new options for low-carbon propulsion. Work related to the characterization of alternative fuels is coordinated with our partners in government and industry, and NASA is close to concluding a TC in this area. Research on alternate propulsion concepts continues to grow and is an important aspect of the ARMD portfolio. Strong partnerships have been a key enabling factor for research on this strategic thrust.

  17. Thrust and power measurements of Olympic swimmers

    Science.gov (United States)

    Wei, Timothy; Wu, Vicki; Hutchison, Sean; Mark, Russell

    2012-11-01

    Elite level swimming is an extremely precise and even choreographed activity. Swimmers not only know the exact number of strokes necessary to take them across the pool, they also plan to be a precise distance from the wall at the end of their last stroke. Too far away and they lose time by drifting into the wall. Too close and their competitor may slide in before their hand comes forward to touch the wall. In this context, it is important to know, in detail, where and how a swimmer propels her/himself through the water. Over the past decade, state-of-the-art flow and thrust measurement diagnostics have been brought to competitive swimming. But the ability to correlate stroke mechanics to thrust production without somehow constraining the swimmer has here-to-fore not been possible. Using high speed video, a simple approach to mapping the swimmer's speed, thrust and net power output in a time resolved manner has been developed. This methodology has been applied to Megan Jendrick, gold medalist in the 100 individual breast stroke and 4 × 100 medley relay events in 2000 and Ariana Kukors, 2009 world champion and continuing world record holder in the 200 individual medley. Implications for training future elite swimmers will be discussed.

  18. The thrust belts of Western North America

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, F.C.

    1993-08-01

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

  19. Thrust Vector Control for Nuclear Thermal Rockets

    Science.gov (United States)

    Ensworth, Clinton B. F.

    2013-01-01

    Future space missions may use Nuclear Thermal Rocket (NTR) stages for human and cargo missions to Mars and other destinations. The vehicles are likely to require engine thrust vector control (TVC) to maintain desired flight trajectories. This paper explores requirements and concepts for TVC systems for representative NTR missions. Requirements for TVC systems were derived using 6 degree-of-freedom models of NTR vehicles. Various flight scenarios were evaluated to determine vehicle attitude control needs and to determine the applicability of TVC. Outputs from the models yielded key characteristics including engine gimbal angles, gimbal rates and gimbal actuator power. Additional factors such as engine thrust variability and engine thrust alignment errors were examined for impacts to gimbal requirements. Various technologies are surveyed for TVC systems for the NTR applications. A key factor in technology selection is the unique radiation environment present in NTR stages. Other considerations including mission duration and thermal environments influence the selection of optimal TVC technologies. Candidate technologies are compared to see which technologies, or combinations of technologies best fit the requirements for selected NTR missions. Representative TVC systems are proposed and key properties such as mass and power requirements are defined. The outputs from this effort can be used to refine NTR system sizing models, providing higher fidelity definition for TVC systems for future studies.

  20. MHD thrust vectoring of a rocket engine

    Science.gov (United States)

    Labaune, Julien; Packan, Denis; Tholin, Fabien; Chemartin, Laurent; Stillace, Thierry; Masson, Frederic

    2016-09-01

    In this work, the possibility to use MagnetoHydroDynamics (MHD) to vectorize the thrust of a solid propellant rocket engine exhaust is investigated. Using a magnetic field for vectoring offers a mass gain and a reusability advantage compared to standard gimbaled, elastomer-joint systems. Analytical and numerical models were used to evaluate the flow deviation with a 1 Tesla magnetic field inside the nozzle. The fluid flow in the resistive MHD approximation is calculated using the KRONOS code from ONERA, coupling the hypersonic CFD platform CEDRE and the electrical code SATURNE from EDF. A critical parameter of these simulations is the electrical conductivity, which was evaluated using a set of equilibrium calculations with 25 species. Two models were used: local thermodynamic equilibrium and frozen flow. In both cases, chlorine captures a large fraction of free electrons, limiting the electrical conductivity to a value inadequate for thrust vectoring applications. However, when using chlorine-free propergols with 1% in mass of alkali, an MHD thrust vectoring of several degrees was obtained.

  1. Aircraft Engine Thrust Estimator Design Based on GSA-LSSVM

    Science.gov (United States)

    Sheng, Hanlin; Zhang, Tianhong

    2017-08-01

    In view of the necessity of highly precise and reliable thrust estimator to achieve direct thrust control of aircraft engine, based on support vector regression (SVR), as well as least square support vector machine (LSSVM) and a new optimization algorithm - gravitational search algorithm (GSA), by performing integrated modelling and parameter optimization, a GSA-LSSVM-based thrust estimator design solution is proposed. The results show that compared to particle swarm optimization (PSO) algorithm, GSA can find unknown optimization parameter better and enables the model developed with better prediction and generalization ability. The model can better predict aircraft engine thrust and thus fulfills the need of direct thrust control of aircraft engine.

  2. Relationships between thrusting and joint systems in the Jaca thrust-top basin, Spanish Pyrenees

    Science.gov (United States)

    Turner, J. P.; Hancock, P. L.

    The Oligo-Miocene rocks of the West Jaca thrust-top basin and adjacent parts of the Ebro basin are cut by up to eight sets of joints and allied mesofractures. The fractures belong to three groups that can be distinguished on the basis of their relative ages and geometry. An older group of joints strikes normal or subnormal to the Pyrenean mountain front and is restricted to subareas (here called front-normal joint domains) coincident with the immediate footwalls of thrusts. Joints striking parallel to a buried lateral ramp characterize a lateral ramp joint domain. Younger joints striking parallel or subparallel to the mountain front occur throughout most of the West Jaca and Ebro basins, and define front-parallel joint domains. The joint domains appear to reflect the geometry and evolution of thrust sheets. Joints in front-normal domains were formed during stretching of footwalls as a result of their loading by overriding thrust sheets. Stretching above a lateral ramp is thought to be responsible for the development of joints in the lateral ramp domain. Joints in the front-parallel domains of the West Jaca basin are related to stretching in growth folds that were amplifying during salt doming. Front-parallel joints in the Ebro basin are attributed to stretching of a foreland basin sequence above a basement flexure related to thrust loading.

  3. Thrust Performance Evaluation of a Turbofan Engine Based on Exergetic Approach and Thrust Management in Aircraft

    Science.gov (United States)

    Yalcin, Enver

    2017-05-01

    The environmental parameters such as temperature and air pressure which are changing depending on altitudes are effective on thrust and fuel consumption of aircraft engines. In flights with long routes, thrust management function in airplane information system has a structure that ensures altitude and performance management. This study focused on thrust changes throughout all flight were examined by taking into consideration their energy and exergy performances for fuel consumption of an aircraft engine used in flight with long route were taken as reference. The energetic and exergetic performance evaluations were made under the various altitude conditions. The thrust changes for different altitude conditions were obtained to be at 86.53 % in descending direction and at 142.58 % in ascending direction while the energy and exergy efficiency changes for the referenced engine were found to be at 80.77 % and 84.45 %, respectively. The results revealed here can be helpful to manage thrust and reduce fuel consumption, but engine performance will be in accordance with operation requirements.

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

    Science.gov (United States)

    Xu, Kunning G; Walker, Mitchell L R

    2009-05-01

    This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The thrust stand position serves as the input to the null-circuit feedback control system and the output is the current to an electromagnetic actuator. Mechanical oscillations are actively damped with an electromagnetic damper. A closed-loop inclination system levels the stand while an active cooling system minimizes thermal effects. The thrust stand incorporates an in situ calibration rig. The thrust of a 3.4 kW Hall thruster is measured for thrust levels up to 230 mN. The uncertainty of the thrust measurements in this experiment is +/-0.6%, determined by examination of the hysteresis, drift of the zero offset and calibration slope variation.

  5. Initiation of a thrust fault revealed by analog experiments

    Science.gov (United States)

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

    2016-08-01

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

  6. Jaw thrust can deteriorate upper airway patency.

    Science.gov (United States)

    von Ungern-Sternberg, B S; Erb, T O; Frei, F J

    2005-04-01

    Upper airway obstruction is a frequent problem in spontaneously breathing children undergoing anesthesia or sedation procedures. Failure to maintain a patent airway can rapidly result in severe hypoxemia, bradycardia, or asystole, as the oxygen demand of children is high and oxygen reserve is low. We present two children with cervical masses in whom upper airway obstruction exaggerated while the jaw thrust maneuver was applied during induction of anesthesia. This deterioration in airway patency was probably caused by medial displacement of the lateral tumorous tissues which narrowed the pharyngeal airway.

  7. Optimum Staging with Varying Thrust Attitude Angle

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1966-07-01

    Full Text Available Optimum staging programme for step rockets of arbitrary number of stages having different specific impulses and mass fractions with stages is derived, the optimization criterion being minimum take-off weight for a desired burntout velocity at an assigned altitude. Variation of thrust attitude angle from stage to stage and effects of gravity factor are taken into account. Analysis is performed for a degenerate problem obtained by relaxing the altitude constraint and it has been shown that problems of Weisbord, Subotowicz, Hall & Zambelli and Malina & Summerfield are the particular cases of the degenerate problem.

  8. Fluid storage and transport in thrust belts: the Gavarnie Thrust system revisited

    Science.gov (United States)

    McCaig, Andrew

    2015-04-01

    There has been renewed interest in the pressure and movement of fluids in thrust systems in recent years with the discovery and increasing importance of slow slip earthquakes. Unfortunately the overpressured regime thought to be the source region for both normal and slow-slip earthquakes is inaccessible to direct observation, so information about the actual water content, flow regimes and permeability structure at the time of thrusting can only be obtained in exhumed rocks. The Gavarnie Thrust System in the Pyrenees (including the immediate footwall of the thrust and overlying thrust sheets) is exceptionally well studied in terms of structural and microstructural work, fluid inclusions, and isotopic tracing of fluid flow. Southward thrusting by 12-15 km occurred during the Eocene, and the current geometry of the thrust is a broad dome, allowing sampling at many locations. There is abundant evidence for near-lithostatic fluid pressures at depths of 8-15 km in the crust and temperatures of 300-400 °C, and fluids at these levels are dominated by hypersaline brines with Cl/Br ratios indicating evaporation of seawater. They are inferred to be derived from widespread Triassic evaporates, and stored in underlying redbeds and fractured basement rocks. There is also evidence from fluid inclusions for periodic pressure cycling down to near-hydrostatic values. This is thought to be related to co-seismic fault valve behaviour with release of fluid both into the shallow thrust and into steeply dipping shear zones in the hangingwall. Isotopic studies of carbonate mylonites along the Gavarnie thrust indicate unidirectional southward (structurally upward) flow of fluid , again probably mainly during transient veining events. These relatively slow moving fluids appear to have fed into a hydrostatic regime with topographically driven flow at higher levels. If time averaged permeability was high, most of the fluid would have rapidly escaped, since there is little opportunity to

  9. Emergency Control Aircraft System Using Thrust Modulation

    Science.gov (United States)

    Burken, John J. (Inventor); Burcham, Frank W., Jr. (Inventor)

    2000-01-01

    A digital longitudinal Aircraft Propulsion Control (APC system of a multiengine aircraft is provided by engine thrust modulation in response to comparing an input flightpath angle signal (gamma)c from a pilot thumbwheel. or an ILS system with a sensed flightpath angle y to produce an error signal (gamma)e that is then integrated (with reasonable limits) to generate a drift correction signal to be added to the error signal (gamma)e after first subtracting a lowpass filtered velocity signal Vel(sub f) for phugoid damping. The output error signal is multiplied by a constant to produce an aircraft thrust control signal ATC of suitable amplitude to drive a throttle servo for all engines. each of which includes its own full-authority digital engine control (FADEC) computer. An alternative APC system omits sensed flightpath angle feedback and instead controls the flightpath angle by feedback of the lowpass filtered velocity signal Vel(sub f) which also inherently provides phugoid damping. The feature of drift compensation is retained.

  10. OMV/VTE variable thrust engine analysis

    Science.gov (United States)

    Larosillere, L.; Litchford, R.; Jeng, S. M.

    1995-01-01

    The objective of the present work is to develop a predictive CFD based analytical tool for the Variable Thrust Engine (VTE) in the Orbital Maneuvering Vehicle (OMV). This objective is being accomplished within the framework of the Los Alamos KIVA computer code for chemically reactive flows with sprays. For the OMV application, the main structure of KIVA is to be retained while reformulating many of the phenomenological submodels, enhancing some of the numerics, and adding more features. The analytical model consists of the general conservation equations for two-phase reactive flows and of submodels for turbulence, chemical reactions, and bipropellant sprays. Tailoring this model to the OMV engine brings about the added complexities of combustion and flow processes that occur in a liquid hypergolic propellant rocket chamber. This report exposes the foundation upon which the analytical tool is being constructed and developed. Results from a cursory computational exercise involving the simulation of the flow and combustion processes in a hypothetical N2H4/N204 rocket engine thrust chamber is presented and discussed.

  11. Experimental Results of Schlicher's Thrusting Antenna

    Science.gov (United States)

    Fralick, Gustave C.; Niedra, Janis M.

    2001-01-01

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

  12. Dynamic Model for Thrust Generation of Marine Propellers

    DEFF Research Database (Denmark)

    2000-01-01

    Mathematical models of propeller thrust and torque are traditionally based on steady state thrust and torque characteristics obtained in model basin or cavitation tunnel tests. Experimental results showed that these quasi steady state models do not accurately describe the transient phenomena...... the eects of transients in the ow over a wide range of operation. The results are essential for accurate thrust control in dynamic positioning and in underwater robotics....

  13. Explicit Low-Thrust Guidance for Reference Orbit Targeting

    Science.gov (United States)

    Lam, Try; Udwadia, Firdaus E.

    2013-01-01

    The problem of a low-thrust spacecraft controlled to a reference orbit is addressed in this paper. A simple and explicit low-thrust guidance scheme with constrained thrust magnitude is developed by combining the fundamental equations of motion for constrained systems from analytical dynamics with a Lyapunov-based method. Examples are given for a spacecraft controlled to a reference trajectory in the circular restricted three body problem.

  14. A 3-D Model of Stacked Thrusts in the Sevier Thrust Belt, Eastern Idaho

    Science.gov (United States)

    Clayton, R. W.; Clayton, S. R.

    2014-12-01

    Using published and new geologic map data and two exploratory wells for control, we constructed a three-dimensional geological model of the Pine Creek area in the Big Hole Mountains of eastern Idaho, where stacked Sevier thrust sheets are exposed at the surface. In this area, Cretaceous crustal shortening displaced and folded strata from Cambrian to Cretaceous in age. Using geologic map data as a primary input to a 3-D model presents a number of challenges, especially representing fault geometries at depth and maintaining strata thicknesses. The highly variable attitudes measured at the surface are also difficult to represent in a subsurface model because they require extensive extrapolation to depth. To overcome these challenges we EarthVision software, which has tools for model construction with minimal data inputs and uses a minimum tension algorithm to create geologically realistic surfaces. We also constructed two primary cross-sections to constrain strata and fault geometries according to structural principles, and used these to guide construction of fault and horizon surfaces. We then designated horizons with the best control as reference horizons to constrain strata geometries, and built the remaining horizons using isochores to add or subtract from those surfaces. The model shows classic flat-ramp thrust geometries as seen farther southeast in the Wyoming section of the thrust belt. The model also shows uniform southwestward tilting of faults and strata in the north end above younger thrusts, but strong effects from a duplex on a younger thrust fault encountered in the southern well, which rotated the strata and older faults above it.

  15. Versatile and Extensible, Continuous-Thrust Trajectory Optimization Tool Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an innovative, versatile and extensible, continuous-thrust trajectory optimization tool for planetary mission design and optimization of...

  16. Improved Propulsion Modeling for Low-Thrust Trajectory Optimization

    Science.gov (United States)

    Knittel, Jeremy M.; Englander, Jacob A.; Ozimek, Martin T.; Atchison, Justin A.; Gould, Julian J.

    2017-01-01

    Low-thrust trajectory design is tightly coupled with spacecraft systems design. In particular, the propulsion and power characteristics of a low-thrust spacecraft are major drivers in the design of the optimal trajectory. Accurate modeling of the power and propulsion behavior is essential for meaningful low-thrust trajectory optimization. In this work, we discuss new techniques to improve the accuracy of propulsion modeling in low-thrust trajectory optimization while maintaining the smooth derivatives that are necessary for a gradient-based optimizer. The resulting model is significantly more realistic than the industry standard and performs well inside an optimizer. A variety of deep-space trajectory examples are presented.

  17. Secondary production of massive quarks in thrust

    Energy Technology Data Exchange (ETDEWEB)

    Hoang, André H. [University of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090 Wien (Austria); Erwin Schrödinger International Institute for Mathematical Physics, University of Vienna, Boltzmanngasse 9, A-1090 Vienna (Austria); Mateu, Vicent [University of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090 Wien (Austria); Pietrulewicz, Piotr [Theory Group, Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg (Germany)

    2016-01-22

    We present a factorization framework that takes into account the production of heavy quarks through gluon splitting in the thrust distribution for e{sup +}e{sup −} → hadrons. The explicit factorization theorems and some numerical results are displayed in the dijet region where the kinematic scales are widely separated, which can be extended systematically to the whole spectrum. We account for the necessary two-loop matrix elements, threshold corrections, and include resummation up to N{sup 3}LL order. We include nonperturbative power corrections through a field theoretical shape function, and remove the O(Λ{sub QCD}) renormalon in the partonic soft function by appropriate mass-dependent subtractions. Our results hold for any value of the quark mass, from an infinitesimally small (merging to the known massless result) to an infinitely large one (achieving the decoupling limit). This is the first example of an application of a variable flavor number scheme to final state jets.

  18. Secondary production of massive quarks in thrust

    Energy Technology Data Exchange (ETDEWEB)

    Hoang, Andre H. [Wien Univ. (Austria). Fakultaet fuer Physik; Vienna Univ. (Austria). Erwin Schroedinger International Institute for Mathematical Physics; Mateu, Vicent [Wien Univ. (Austria). Fakultaet fuer Physik; Pietrulewicz, Piotr [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie

    2014-12-15

    We present a factorization framework that takes into account the production of heavy quarks through gluon splitting in the thrust distribution for e{sup +}e{sup -}→hadrons. The explicit factorization theorems and some numerical results are displayed in the dijet region where the kinematic scales are widely separated, which can be extended systematically to the whole spectrum. We account for the necessary two-loop matrix elements, threshold corrections, and include resummation up to N{sup 3}LL order. We include nonperturbative power corrections through a field theoretical shape function, and remove the O(Λ{sub QCD}) renormalon in the partonic soft function by appropriate mass-dependent subtractions. Our results hold for any value of the quark mass, from an infinitesimally small (merging to the known massless result) to an infinitely large one (achieving the decoupling limit). This is the first example of an application of a variable flavor number scheme to final state jets.

  19. Morphological Considerations of Fish Fin Shape on Thrust Generation

    Directory of Open Access Journals (Sweden)

    Kenji Kikuchi

    2014-01-01

    Full Text Available In this study, we aimed to determine the relationship between thrust generation and fish fin shape. To compare the effect fin shape had on thrust generation, we categorized the morphological shapes of fish fins into equilateral polygonal shapes. Polygonal fins were used to generate thrust that depended only on shape. These fins were constructed of a hard elastic material to eliminate any influence of shape deformation. A servomotor with a reciprocal rotation moved a fin cyclically, and thrust was experimentally measured using a strain gage system. Thrust tended to be proportional to the inertia moment of a fin, which indicated difficulty with rotation. Moreover, this trend for thrust generation was directly related to the number of apexes of a polygonal fin. The force translated ratio, which was thrust divided by the force required for fin rotation, was evaluated to determine the hydrodynamic characteristics of fins. This finding showed that the force translated ratio of a fin increased with increased movable perimeter length. The greatest thrust was generated by a triangular fin rotated at its apex, which is often seen in general fish tail fins, whereas the hydrodynamic characteristics were the worst in polygonal fins.

  20. Electronics Engineering Department Thrust Area report FY'84

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-01-01

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

  1. A magnetic coupling thrust stand for microthrust measurements

    Science.gov (United States)

    Wright, W. P.; Ferrer, P.

    2016-01-01

    A direct thrust measurement system that is based on a horizontal lever and utilizes a novel magnetic coupling mechanism to measure thrust has been developed. The system is capable of measuring thrusts as low as 10’s of μN. While zero drift is observed in the balance, tests have shown that they do not have an appreciable effect on thrust measurements. The thrust stand’s sensitivity can be adjusted by shifting the position of the coupling magnet inside the stand’s thrust support member, which allows flexibility for testing both higher and lower powered thrusters. The thrust stand has been modeled theoretically and the predicted results from the model are compared with experimentally measured data. The system was tested using a simple cold gas thruster and provided credible results that can be compared with other systems studied in the literature. Advantages include that the thrust stand is very cheap and easy to construct and further, the calibration process takes no longer than half an hour, facilitating rapid turnaround times while still retaining accuracy. Repeatability tests have shown that the balance gives consistent results.

  2. Impact of plasma noise on a direct thrust measurement system

    Science.gov (United States)

    Pottinger, S. J.; Lamprou, D.; Knoll, A. K.; Lappas, V. J.

    2012-03-01

    In order to evaluate the accuracy and sensitivity of a pendulum-type thrust measurement system, a linear variable differential transformer (LVDT) and a laser optical displacement sensor have been used simultaneously to determine the displacement resulting from an applied thrust. The LVDT sensor uses an analog interface, whereas the laser sensor uses a digital interface to communicate the displacement readings to the data acquisition equipment. The data collected by both sensors show good agreement for static mass calibrations and validation with a cold gas thruster. However, the data obtained using the LVDT deviate significantly from that of the laser sensor when operating two varieties of plasma thrusters: a radio frequency (RF) driven plasma thruster, and a DC powered plasma thruster. Results establish that even with appropriate shielding and signal filtering the LVDT sensor is subject to plasma noise and radio frequency interactions which result in anomalous thrust readings. Experimental data show that the thrust determined using the LVDT system in a direct current plasma environment and a RF discharge is approximately a factor of three higher than the thrust values obtained using a laser sensor system for the operating conditions investigated. These findings are of significance to the electric propulsion community as LVDT sensors are often utilized in thrust measurement systems and accurate thrust measurement and the reproducibility of thrust data is key to analyzing thruster performance. Methods are proposed to evaluate system susceptibility to plasma noise and an effective filtering scheme presented for DC discharges.

  3. 14 CFR 25.945 - Thrust or power augmentation system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Thrust or power augmentation system. 25.945 Section 25.945 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.945 Thrust or power...

  4. Simulations of directed energy thrust on rotating asteroids

    Science.gov (United States)

    Griswold, Janelle; Madajian, Jonathan; Johansson, Isabella; Pfau, Krysten; Lubin, Philip; Hughes, Gary B.; Gilkes, Aidan; Meinhold, Peter; Motta, Caio; Brashears, Travis; Zhang, Qicheng

    2015-09-01

    Asteroids that threaten Earth could be deflected from their orbits using directed energy to vaporize the surface, because the ejected plume creates a reaction thrust that alters the asteroid's trajectory. One concern regarding directed energy deflection is the rotation of the asteroid, as this will reduce the average thrust magnitude and modify the thrust direction. Flux levels required to evaporate surface material depend on surface material composition and albedo, thermal, and bulk mechanical properties of the asteroid, and rotation rate. The observed distribution of asteroid rotation rates is used, along with an estimated range of material and mechanical properties, as input to a 3D thermal-physical model to calculate the resultant thrust vector. The model uses a directed energy beam, striking the surface of a rotating sphere with specified material properties, beam profile, and rotation rate. The model calculates thermal changes in the sphere, including vaporization and mass ejection of the target material. The amount of vaporization is used to determine a thrust magnitude that is normal to the surface at each point on the sphere. As the object rotates beneath the beam, vaporization decreases, as the temperature drops and causes both a phase shift and magnitude decrease in the average thrust vector. A surface integral is calculated to determine the thrust vector, at each point in time, producing a 4D analytical model of the expected thrust profile for rotating objects.

  5. The Construction of The Mid-leveled Administrators' Model of Personality in Department Store%百货类企业中层管理干部胜任人格模型建立

    Institute of Scientific and Technical Information of China (English)

    罗灵娜

    2012-01-01

    Personality is an important element of Differentiating Competency,which can comparatively reflect the real hidden traits of the employers.It can be used as the accordance to employ the staff with high efficiency and great talent.The study,which is based on the analysis about the relations between the comprehensive evaluation and the personality of the mid-leveled administrators in company D,finds out that among the 16 personality factors,only warmth,sensitivity,and privateness have effect on the comprehensive evaluation.In accordance to the result of study,this paper taking the three personality factors as the basis,has constructed the mid-leveled administrators' Model of Personality,as well as the personality test which is fit for employing the mid-leveled administrators of company D.%人格是鉴别胜任力中重要的组成要素,能够较真实地反映应聘者的内隐特征,可作为招聘具有高绩效潜能人才的依据。本研究通过对D公司中层管理干部的综合评价绩效指标与人格之间的关系进行调查分析,发现16种人格特质中,只有乐群性、敏感性、世故性三个因子对综合评价绩效指标具有影响。根据该结果,本研究以这三种人格特质为基础建立了D公司中层管理干部胜任人格模型,并修订了适合D公司招聘中层管理干部的人格测验。

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

    Science.gov (United States)

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

    2014-01-01

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

  7. Thrust transport directions and thrust sheet restoration in the caledonides of finnmark, North Norway

    Science.gov (United States)

    Townsend, C.

    Thrust sheets of the Late Cambrian to Early Ordovician Finnmarkian phase of the Caledonian Orogeny of Finnmark, northern Norway, have been displaced, firstly to the SE, under ductile conditions and later, under more brittle conditions, towards the ESE/E. These thrust sheets have been sequentially restored with the aid of branch-lines and balanced cross-sections. The minimum displacement for each thrust sheet is: Gaissa Nappe, 165 km; Laksefjord Nappe Complex, 105 km; Komagfjord Antiformal Stack, 30 km; and Kalak Nappe Complex, 75 km. This restoration has three significant implications: (1) the total displacement across the Finnmark Caledonides is over 375 km; (2) the Raipas Supergroup exposed within the Komagfjord Window, the allochthonous origin of which has previously been contentious, has been displaced as a basement horse, firstly to the SE and later to the ESE/E by at least 375 km; and (3) in a palinspastic reconstruction the Raipas Supergroup basement did not form the Finnmark Ridge, the source area for the sediments of the Laksefjord Nappe Complex. This restoration does not include the deformation within the Kalak Nappe Complex or the imbricates of the Gaissa Nappe in East Finnmark.

  8. Reaction thrust of water jet for conical nozzles

    Institute of Scientific and Technical Information of China (English)

    HUANG Guo-qin; YANG You-sheng; LI Xiao-hui; ZHU Yu-quan

    2009-01-01

    Clear knowledge on the reaction thrust of water jet is valuable for better design of water jet propulsion system.In this paper,theoretical,numerical and experimental studies were carried out to investigate the effects of the nozzle geometry as well as the inlet conditions on the reaction thrust of water jet.Comparison analyses reveal that the reaction thrust has a direct proportional relationship with the product of the inlet pressure,the square of flow rate and two-thirds power exponent of the input power.The results also indicate that the diameter of the cylinder column for the conical nozzle has great influence on the reaction thrust characteristics.In addition,the best values of the half cone angle and the cylinder column length exist to make the reaction thrust reach its maximum under the same inlet conditions.

  9. New Highly Dynamic Approach for Thrust Vector Control

    Science.gov (United States)

    Hecht, M.; Ettl, J.; Grothe, D.; Hrbud, I.

    2015-09-01

    For a new launcher system a thrust vector control system is needed. This launch vehicle system consists of two rockets which are namely the VS-50 (two-stage suborbital vehicle) and the VLM-1 (three-stage microsatellite launch vehicle). VLM-1 and VS-50 are developed in a cooperation between the German Aerospace Center (DLR) and the Brazilian Aeronautics and Space Institute (IAE). To keep these two rockets on its trajectory during flight a highly dynamic thrust vector control system is required. For the purpose of developing such a highly dynamic thrust vector control system a master thesis was written by the author. The development includes all mechanical constructions as well as control algorithms and electronics design. Moreover an optimization of control algorithms was made to increase the dynamic capabilities of the thrust vector control system. The composition of the right components plus the sophisticated control algorithm make the thrust vector control system highly dynamic.

  10. Analysis of properties of thrust bearing in ship propulsion system

    Science.gov (United States)

    Wu, Zhu-Xin; Liu, Zheng-Lin

    2010-06-01

    Thrust bearing is a key component of the propulsion system of a ship. It transfers the propulsive forces from the propeller to the ship’s hull, allowing the propeller to push the ship ahead. The performance of a thrust bearing pad is critical. When the thrust bearing becomes damaged, it can cause the ship to lose power and can also affect its operational safety. For this paper, the distribution of the pressure field of a thrust pad was calculated with numerical method, applying Reynolds equation. Thrust bearing properties for loads were analyzed, given variations in outlet thickness of the pad and variations between the load and the slope of the pad. It was noticed that the distribution of pressure was uneven. As a result, increases of both the outlet thickness and the slope coefficient of the pad were able to improve load bearing capability.

  11. 昆明世博生态城半山邻里植物群落结构分析%Analysis of plant community structure of Mid-levels neighborhood in Kunming expoeco-city

    Institute of Scientific and Technical Information of China (English)

    董素君; 赵林森

    2014-01-01

    以世博生态城半山邻里居住区为研究对象,从园林植物群落的物种结构、水平结构、垂直结构和时间结构4方面对该居住区的绿化环境进行分析和评价。%Taking Mid-levels neighborhood housing estate in the Expo eco-city as study object, this paper analyzed and evaluated its green environment from the four aspects of species structure, horizontal structures, vertical structure and temporal structure of gardening plant communities.

  12. Initial Thrust Measurements of Marshall's Ion-ioN Thruster

    Science.gov (United States)

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

    2015-01-01

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

  13. Sandbox modelling of sequential thrusting in a mechanically two-layered system and its implications in fold-and-thrust belts

    Science.gov (United States)

    Saha, Puspendu; Bose, Santanu; Mandal, Nibir

    2016-10-01

    Many fold-and-thrust belts display multi-storied thrust sequences, characterizing a composite architecture of the thrust wedges. Despite dramatic progress in sandbox modelling over the last three decades, our understanding of such composite thrust-wedge mechanics is limited and demands a re-visit to the problem of sequential thrusting in mechanically layered systems. This study offers a new approach to sandbox modelling, designed with a two-layered sandpack simulating a mechanically weak Coulomb layer, resting coherently upon a stronger Coulomb layer. Our experimental models reproduce strikingly similar styles of the multi-storied frontal thrust sequences observed in natural fold-and- thrust belts. The upper weak horizon undergoes sequential thrusting at a high spatial frequency, forming numerous, closely spaced frontal thrusts, whereas the lower strong horizon produces widely spaced thrusts with progressive horizontal shortening. This contrasting thrust progression behaviour gives rise to composite thrust architecture in the layered sandpack. We show the evolution of such composite thrust sequences as a function of frictional strength (μb) at the basal detachment and thickness ratio (Tr) between the weak and strong layers. For any given values of Tr and μb, the two thrust sequences progress at different rates; the closely-spaced, upper thrust sequence advances forelandward at a faster rate than the widely-spaced, lower thrust sequence. Basal friction (μb) has little effects on the vergence of thrusts in the upper weak layer; they verge always towards foreland, irrespective of Tr values. But, the lower strong layer develops back-vergent thrusts when μb is low (∼0.36). In our experiments, closely spaced thrusts in the upper sequence experience intense reactivation due to their interaction with widely spaced thrusts in the lower sequence. The interaction eventually affects the wedge topography, leading to two distinct parts: inner and outer wedges

  14. Early history and reactivation of the rand thrust, southern California

    Science.gov (United States)

    Postlethwaite, Clay E.; Jacobson, Carl E.

    The Rand thrust of the Rand Mountains in the northwestern Mojave Desert separates an upper plate of quartz monzonite and quartzofeldspathic to amphibolitic gneiss from a lower plate of metagraywacke and mafic schist (Rand Schist). The Rand thrust is considered part of the regionally extensive Vincent/Chocolate Mountain thrust system, which is commonly believed to represent a Late Cretaceous subduction zone. The initial direction of dip and sense of movement along the Vincent/Chocolate Mountain thrust are controversial. Microfabrics of mylonites and quartzites from the Rand Mountains were analyzed in an attempt to determine transport direction for this region, but the results are ambiguous. In addition, the southwestern portion of the Rand thrust was found to have been reactivated as a low-angle normal fault after subduction. Reactivation might have occurred shortly after subduction, in which case it could account for the preservation of high-pressure mineral assemblages in the Rand Schist, or it could be related to mid-Tertiary extension in the western United States. In either event, the reactivation might be responsible for the complicated nature of the microfabrics. The Rand Schist exhibits an inverted metamorphic zonation. Isograds in the schist are not significantly truncated by the reactivated segment of the Rand thrust. This indicates that other segments of the Vincent/Chocolate Mountain thrust should be re-evaluated for the possibility of late movement, even if they show an apparently undisturbed inverted metamorphic zonation.

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

    Science.gov (United States)

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

    2010-01-01

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

  16. Effect of tongue thrust swallowing on position of anterior teeth.

    Science.gov (United States)

    Jalaly, Tahereh; Ahrari, Farzaneh; Amini, Foroozandeh

    2009-01-01

    There is no consensus about the effect of tongue thrusting on incisor position. The purpose of this study was to evaluate the position of anterior teeth in growing children with tongue thrust swallowing. In the present study 193 subjects with an age range of 9 to 13 years participated. All the patients were examined by a trained investigator and those having tongue thrust swallowing were selected and the position of their anterior teeth was compared with a control group consisting of 36 subjects with normal occlusion. Data was analyzed by independent sample t-test. Among the 193 students who were examined in this study, 10 cases (5%) were diagnosed to be tongue thrusters. Overjet was significantly increased in tongue thrust individuals (P 0.05). The results indicated that tongue thrust may have an environmental effect on dentofacial structures. Considering the high incidence of tongue thrust in orthodontic patients, it is suggested that dental practitioners observe patients of all ages and those in all stages of orthodontic treatment for evidence of tongue thrust swallowing.

  17. Structural style of the Marathon thrust belt, West Texas

    Science.gov (United States)

    Hickman, Robert G.; Varga, Robert J.; Altany, Robert M.

    2009-09-01

    The Marathon portion of the Ouachita thrust belt consists of a highly deformed allochthonous wedge of Cambrian-Pennsylvanian slope strata (Marathon facies) that was transported to the northwest and emplaced over Pennsylvanian foredeep sediments. The foredeep strata in turn overlie early-middle Paleozoic shelfal sediments which are deformed by late Paleozoic basement-involved reverse faults. The Dugout Creek thrust is the basal thrust of the allochthon. Shortening in this sheet and overlying sheets is ˜80%. Steep imbricate faults link the Dugout Creek thrust to upper level detachments forming complex duplex zones. Progressive thrusting and shortening within the allochthon folded the upper level detachments and associated thrust sheets. The Caballos Novaculite is the most competent unit within the Marathon facies and controlled development of prominent detachment folds. Deeper imbricate sheets composed of the Late Pennsylvanian foredeep strata, and possibly early-middle Paleozoic shelfal sediments developed concurrently with emplacement of the Marathon allochthon and folded the overlying allochthon. Following termination of thrusting in the earliest Permian, subsidence and deposition shifted northward to the Delaware, Midland and Val Verde foreland basins.

  18. Foreland normal fault control on northwest Himalayan thrust front development

    Science.gov (United States)

    Blisniuk, Peter M.; Sonder, Leslie J.; Lillie, Robert J.

    1998-10-01

    In the Trans-Indus Ranges along the western part of the northwest Himalayan thrust front, unconformities, changes in paleocurrent directions, and locally derived conglomerates in synorogenic foreland basin deposits provide evidence for major local deformation at ≥3.5 Ma. The tectonic history of the Trans-Indus Ranges has previously been described in terms of a single episode of major thrusting at ≤1 Ma, thus our work implies that there were two distinct phases of deformation. In conjunction with published evidence in the Salt Range to the east for two phases of deformation (˜6 to 5 Ma, and ˜2.5 Ma to present), this study demonstrates that these two phases of deformation are regionally significant and probably correlative along the entire present-day NW Himalayan thrust front. Reconstruction of possible source areas for the locally derived conglomerates shows that the earlier deformation is probably related to normal faulting. These results suggest that the tectonic evolution of the area along the present-day thrust front is characterized by (1) latest Miocene to early Pliocene formation of north dipping normal fault zones (total throw ≥ 600 m) within the foreland basin, related to syn-orogenic flexure of the Indian plate, and (2) late Pliocene to early Pleistocene initiation of south directed thrusting along the present-day thrust front, related to outward growth of the NW Himalayan thrust wedge. The location of the present-day thrust front appears to be controlled by north dipping normal faults and monoclines that formed during the earlier deformation and subsequently localized structural ramps during later thrusting.

  19. Role of detachments and thrust kinematics in Structural evolution of Kohat and Potwar fold thrust belt in Pakistan

    Science.gov (United States)

    Ghani, Humaad; Zeilinger, Gerold; Sobel, Edward; Heidarzadeh, Ghasem

    2016-04-01

    The Kohat and Potwar fold thrust belts in Pakistan represent the outermost external zone of the Himalayan fold and thrust system. The Main Boundary thrust marks their northern extent, showing that they are genetically linked; however, both exhibit a distinct contrast between the structural style at the surface and subsurface. This contrast becomes more conspicuous at the leading edge of the thrust belt where the Potwar allochothon extends further south, linked to Kohat in the north via an active strike-slip fault. Previous workers explained the structural evolution of the two belts separately, disregarding the influence of similar fold and thrusts developed in both belts. This research focuses on the preparation of a 3D structural model at the boundary of the two thrust belts to understand similarities and differences in their structural style and evolution. The model is constrained by integrating field, seismic and well data for better subsurface interpretation. Cross sections show that Potwar evolved on thrust faults originating from a basal detachment in Precambrian (pC) salt and terminating in Miocene Molasse forming duplexes of pre Himalayan strata. To the south, the Potwar allochothon is glided over a salt detachment with rare internal deformation toward its leading edge, forming fault bend fold thrust structure known as Salt range. The structural evolution towards the west in Kohat results from deformation on multiple detachment horizons at the pC salt, Eocene evaporites and Miocene Molasse. Disharmonic folding over Eocene evaporites is evident from their presence in the cores of outcropping folds. In the subsurface, closely spaced thrusts cut up section from basal detachment terminates in Eocene evaporites forming duplex in northern part of area. In south change of lithological facies from evaporites to limestone shift detachment level upward in to molasse strata which resemble structural style in northern Potwar. Thrusts at the surface evolved from the

  20. Thrust measurement method verification and analytical studies on a liquid-fueled pulse detonation engine

    Directory of Open Access Journals (Sweden)

    Lu Jie

    2014-06-01

    Full Text Available In order to test the feasibility of a new thrust stand system based on impulse thrust measurement method, a liquid-fueled pulse detonation engine (PDE is designed and built. Thrust performance of the engine is obtained by direct thrust measurement with a force transducer and indirect thrust measurement with an eddy current displacement sensor (ECDS. These two sets of thrust data are compared with each other to verify the accuracy of the thrust performance. Then thrust data measured by the new thrust stand system are compared with the verified thrust data to test its feasibility. The results indicate that thrust data from the force transducer and ECDS system are consistent with each other within the range of measurement error. Though the thrust data from the impulse thrust measurement system is a litter lower than that from the force transducer due to the axial momentum losses of the detonation jet, the impulse thrust measurement method is valid when applied to measure the averaged thrust of PDE. Analytical models of PDE are also discussed in this paper. The analytical thrust performance is higher than the experimental data due to ignoring the losses during the deflagration to detonation transition process. Effect of equivalence ratio on the engine thrust performance is investigated by utilizing the modified analytical model. Thrust reaches maximum at the equivalence ratio of about 1.1.

  1. Thrust measurement method verification and analytical studies on a liquid-fueled pulse detonation engine

    Institute of Scientific and Technical Information of China (English)

    Lu Jie; Zheng Longxi; Wang Zhiwu; Peng Changxin; Chen Xinggu

    2014-01-01

    In order to test the feasibility of a new thrust stand system based on impulse thrust mea-surement method, a liquid-fueled pulse detonation engine (PDE) is designed and built. Thrust per-formance of the engine is obtained by direct thrust measurement with a force transducer and indirect thrust measurement with an eddy current displacement sensor (ECDS). These two sets of thrust data are compared with each other to verify the accuracy of the thrust performance. Then thrust data measured by the new thrust stand system are compared with the verified thrust data to test its feasibility. The results indicate that thrust data from the force transducer and ECDS system are consistent with each other within the range of measurement error. Though the thrust data from the impulse thrust measurement system is a litter lower than that from the force transducer due to the axial momentum losses of the detonation jet, the impulse thrust measurement method is valid when applied to measure the averaged thrust of PDE. Analytical models of PDE are also discussed in this paper. The analytical thrust performance is higher than the experimental data due to ignor-ing the losses during the deflagration to detonation transition process. Effect of equivalence ratio on the engine thrust performance is investigated by utilizing the modified analytical model. Thrust reaches maximum at the equivalence ratio of about 1.1.

  2. Interplay of thrust, back-thrust, strike-slip and salt tectonics in a fold and thrust belt system: an example from Zakynthos Island, Greece

    Science.gov (United States)

    Zelilidis, A.; Papatheodorou, G.; Maravelis, A. G.; Christodoulou, D.; Tserolas, P.; Fakiris, E.; Dimas, X.; Georgiou, N.; Ferentinos, G.

    2016-10-01

    The southwestern flank of the Hellenic fold and thrust belt, situated along the southern edge of the Dinarides-Albanides-Hellenides continental convergent zone, was examined for reconstructing the tectonic deformation. This investigation presents an integrated study of onshore sedimentological and structural analyses, as well as offshore seismic lines, across the Pliocene-Pleistocene sedimentary succession in Zakynthos Island. Back-thrust faults, using the Triassic evaporites as decollement surface, during the Pliocene, and coeval diapiric intrusions formed three sub-basins on the hangingwall of the Kalamaki back-thrust fault. This interaction is responsible for the growth of the Skopos Mountain and the soft sediment deformation that formed synclines and slumps, respectively. Back-thrust and strike-slip faults were active during the early Pleistocene, and diapiric intrusions modified the bathymetry on the sea floor, giving rise to slumps and recumbent folds. At least five events of synsedimentary diapiric intrusions have been recognized and are marked by five slump horizons. During the Holocene, the diapiric intrusions between the Kalamaki back-thrust and the Vrachionas anticline could be either related to normal faults or gravitationally driven.

  3. Out-of-sequence thrusting in polycyclic thrust belts: An example from the Mesozoic Yanshan belt, North China Craton

    Science.gov (United States)

    Li, Chengming; Zhang, Changhou; Cope, Tim D.; Lin, Yi

    2016-09-01

    The EW trending Yanshan belt, an intraplate fold-thrust belt located in the northern North China Craton that has experienced several episodes of deformation widely separated in time, is characterized by out-of-sequence thrusts. According to detailed mapping in the central Yanshan belt, five geometric and stratigraphic criteria used to aid in determining whether a thrust has an out-of-sequence geometry or not can be recognized. They are (1) unconformable relationships, (2) inclination of fault surfaces, (3) irregular changes in apparent offset along strike, (4) short fault length relative to apparent offset, and (5) in-sequence geometry. With the help of these criteria, two generations of out-of-sequence thrusts that postdate the original in-sequence thrusting in the central Yanshan belt are recognized. The ancestral southward verging fold-and-thrust belt that formed prior to 180 Ma was deformed and cut by two younger generations of faults that are probably more deeply rooted and are constrained to between 172-165 Ma and 152-135 Ma. A series of thrusts with opposite vergence formed during the last period, resulting in abundant abnormal field relationships such as younger-on-older thrust relations, fold truncation, and cutting down-section. The nature and occurrence of faults in the Yanshan belt implies that superimposed deformation, a common feature in polycyclic orogenic belts, is a mechanism for the generation of out-of-sequence thrusting. This adds to mechanisms already described in the literature, such as maintaining constant critical taper at an orogenic scale, inhibition of the deformation front, and lateral changes in the nature of the décollement horizons.

  4. Aerodynamics of thrust vectoring by Navier-Stokes solutions

    Science.gov (United States)

    Tseng, Jing-Biau; Lan, C. Edward

    1991-01-01

    Induced aerodynamics from thrust vectoring are investigated by a computational fluid dynamic method. A thin-layer Reynolds-averaged Navier-Stokes code with multiblock capability is used. Jet properties are specified on the nozzle exit plane to simulate the jet momentum. Results for a rectangular jet in a cross flow are compared with data to verify the code. Further verification of the calculation is made by comparing the numerical results with transonic data for a wing-body combination. Additional calculations were performed to elucidate the following thrust vectoring effects: the thrust vectoring effect on shock and expansion waves, induced effects on nearby surfaces, and the thrust vectoring effect on the leading edge vortex.

  5. Nitrous Oxide Liquid Injection Thrust Vector Control System Testing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Nitrous Oxide-fed Liquid Thrust Vector Control system is proposed as an efficient method for vehicle attitude control during powered flight. Pulled from a N2O main...

  6. Improved Rhenium Thrust Chambers for In-Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation-cooled, bipropellant thrust chambers are being considered for the ascent/descent engines and reaction control systems (RCS) for future NASA missions such...

  7. Fourth Programme Cycle in Population Education Addresses New Thrusts.

    Science.gov (United States)

    Population Education Newsletter and Forum, 1987

    1987-01-01

    Discusses the developments of the Regional Population Education Program of the Unesco Principal Regional Office for Asia and the Pacific during the period 1984-87. Discusses new projects, technical assistance activities, national capabilities, and new program thrusts. (TW)

  8. Optimal Thrust Vectoring for an Annular Aerospike Nozzle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  9. Separability of drag and thrust in undulatory animals and machines

    National Research Council Canada - National Science Library

    Bale, Rahul; Shirgaonkar, Anup A; Neveln, Izaak D; Bhalla, Amneet Pal Singh; MacIver, Malcolm A; Patankar, Neelesh A

    2014-01-01

    .... Prior approaches have failed to provide a separation of these two forces for undulatory swimmers such as lamprey and eels, where most parts of the body are simultaneously generating drag and thrust...

  10. Improved Rhenium Thrust Chambers for In-Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation-cooled, bipropellant thrust chambers are being considered for the ascent/descent engines and reaction control systems for NASA missions such as Mars Sample...

  11. Lower extremity thrust and non-thrust joint mobilization for patellofemoral pain syndrome: a case report.

    Science.gov (United States)

    Simpson, Brad G; Simon, Corey B

    2014-05-01

    A 40-year old female presented to physical therapy with a one-year history of insidious right anteromedial and anterolateral knee pain. Additionally, the patient had a history of multiple lateral ankle sprains bilaterally, the last sprain occurring on the right ankle 1 year prior to the onset of knee pain. The patient was evaluated and given a physical therapy diagnosis of patellofemoral pain syndrome (PFPS), with associated talocrural and tibiofemoral joint hypomobility limiting ankle dorsiflexion and knee extension, respectively. Treatment included a high-velocity low amplitude thrust manipulation to the talocrural joint, which helped restore normal ankle dorsiflexion range of motion. The patient also received tibiofemoral joint non-thrust manual therapy to regain normal knee extension mobility prior to implementing further functional progression exercises to her home program (HEP). This case report highlights the importance of a detailed evaluation of knee and ankle joint mobility in patients presenting with anterior knee pain. Further, manual physical therapy to the lower extremity was found to be successful in restoring normal movement patterns and pain-free function in a patient with chronic anterior knee pain.

  12. The Prevalence of Tongue Thrusting in Patients with Periodontal Disease

    OpenAIRE

    S.A Miremadi; A.A. Khoshkhounejad; E. Mahdavi

    2005-01-01

    Statement of Problem: Tongue thrust and/or its consequent swallowing pattern are amongst the parafunctional habits that have always been considered as etiological factors for dental disorders by different investigators.Purpose: The aim of this study was to investigate the prevalence of tongue thrusting and the incidence of periodontal disorders associated with this habit among patients referred to the Department of Periodontology, School of Dentistry, Tehran University of Medical Sciences.Mat...

  13. Aerodynamics of indirect thrust measurement by the impulse method

    Institute of Scientific and Technical Information of China (English)

    Cheng-Kang Wu; Hai-Xing Wang; Xian Meng; Xi Chen; Wen-Xia Pan

    2011-01-01

    The aerodynamic aspects of indirect thrust measurement by the impulse method have been studied both experimentally and numerically.The underlying basic aerodynamic principle is outlined, the phenomena in subsonic,supersonic and arc-heated jets are explored, and factors affecting the accuracy of the method are studied and discussed.Results show that the impulse method is reliable for indirect thrust measurement if certain basic requirements are met,and a simple guideline for its proper application is given.

  14. Acoustically shielded exhaust system for high thrust jet engines

    Science.gov (United States)

    Carey, John P. (Inventor); Lee, Robert (Inventor); Majjigi, Rudramuni K. (Inventor)

    1995-01-01

    A flade exhaust nozzle for a high thrust jet engine is configured to form an acoustic shield around the core engine exhaust flowstream while supplementing engine thrust during all flight conditions, particularly during takeoff. The flade airflow is converted from an annular 360.degree. flowstream to an arcuate flowstream extending around the lower half of the core engine exhaust flowstream so as to suppress exhaust noise directed at the surrounding community.

  15. The Quaternary thrust system of the northern Alaska Range

    Science.gov (United States)

    Bemis, Sean P.; Carver, Gary A.; Koehler, Richard D.

    2012-01-01

    The framework of Quaternary faults in Alaska remains poorly constrained. Recent studies in the Alaska Range north of the Denali fault add significantly to the recognition of Quaternary deformation in this active orogen. Faults and folds active during the Quaternary occur over a length of ∼500 km along the northern flank of the Alaska Range, extending from Mount McKinley (Denali) eastward to the Tok River valley. These faults exist as a continuous system of active structures, but we divide the system into four regions based on east-west changes in structural style. At the western end, the Kantishna Hills have only two known faults but the highest rate of shallow crustal seismicity. The western northern foothills fold-thrust belt consists of a 50-km-wide zone of subparallel thrust and reverse faults. This broad zone of deformation narrows to the east in a transition zone where the range-bounding fault of the western northern foothills fold-thrust belt terminates and displacement occurs on thrust and/or reverse faults closer to the Denali fault. The eastern northern foothills fold-thrust belt is characterized by ∼40-km-long thrust fault segments separated across left-steps by NNE-trending left-lateral faults. Altogether, these faults accommodate much of the topographic growth of the northern flank of the Alaska Range.Recognition of this thrust fault system represents a significant concern in addition to the Denali fault for infrastructure adjacent to and transecting the Alaska Range. Although additional work is required to characterize these faults sufficiently for seismic hazard analysis, the regional extent and structural character should require the consideration of the northern Alaska Range thrust system in regional tectonic models.

  16. Separability of drag and thrust in undulatory animals and machines

    OpenAIRE

    Bale, R; Shirgaonkar, AA; Neveln, ID; Bhalla, APS; MacIver, MA; Patankar, NA

    2014-01-01

    For nearly a century, researchers have tried to understand the swimming of aquatic animals in terms of a balance between the forward thrust from swimming movements and drag on the body. Prior approaches have failed to provide a separation of these two forces for undulatory swimmers such as lamprey and eels, where most parts of the body are simultaneously generating drag and thrust. We nonetheless show that this separation is possible, and delineate its fundamental basis in undulatory swimmers...

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

    Science.gov (United States)

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

    2014-01-01

    This paper describes the eight-day August 2013 test campaign designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma. This paper will not address the physics of the quantum vacuum plasma thruster, but instead will describe the test integration, test operations, and the results obtained from the test campaign. Approximately 30-50 micro-Newtons of thrust were recorded from an electric propulsion test article consisting primarily of a radio frequency (RF) resonant cavity excited at approximately 935 megahertz. Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level, within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure. Several different test configurations were used, including two different test articles as well as a reversal of the test article orientation. In addition, the test article was replaced by an RF load to verify that the force was not being generated by effects not associated with the test article. The two test articles were designed by Cannae LLC of Doylestown, Pennsylvania. The torsion pendulum was designed, built, and operated by Eagleworks Laboratories at the NASA Johnson Space Center of Houston, Texas. Approximately six days of test integration were required, followed by two days of test operations, during which, technical issues were discovered and resolved. Integration of the two test articles and their supporting equipment was performed in an iterative fashion between the test bench and the vacuum chamber. In other words, the test article was tested on the bench, then moved to the chamber, then moved back as needed to resolve issues. Manual frequency control was required throughout the test. Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not

  18. Characterization of aircraft noise during thrust reverser engagement

    Science.gov (United States)

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

    2005-09-01

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

  19. Application of Chaboche Model in Rocket Thrust Chamber Analysis

    Science.gov (United States)

    Asraff, Ahmedul Kabir; Suresh Babu, Sheela; Babu, Aneena; Eapen, Reeba

    2017-06-01

    Liquid Propellant Rocket Engines are commonly used in space technology. Thrust chamber is one of the most important subsystems of a rocket engine. The thrust chamber generates propulsive thrust force for flight of the rocket by ejection of combustion products at supersonic speeds. Often double walled construction is employed for these chambers. The thrust chamber investigated here has its hot inner wall fabricated out of a high thermal conductive material like copper alloy and outer wall made of stainless steel. Inner wall is subjected to high thermal and pressure loads during operation of engine due to which it will be in the plastic regime. Main reasons for the failure of such chambers are fatigue in the plastic range (called as low cycle fatigue since the number of cycles to failure will be low in plastic range), creep and thermal ratcheting. Elasto plastic material models are required to simulate the above effects through a cyclic stress analysis. This paper gives the details of cyclic stress analysis carried out for the thrust chamber using different plasticity model combinations available in ANSYS (Version 15) FE code. The best model among the above is applied in the cyclic stress analysis of two dimensional (plane strain and axisymmetric) and three dimensional finite element models of thrust chamber. Cyclic life of the chamber is calculated from stress-strain graph obtained from above analyses.

  20. Thrust stand for vertically oriented electric propulsion performance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Trevor [University of Tennessee Space Institute, Tullahoma, Tennessee 37388 (United States); Polzin, Kurt A. [NASA, Marshall Space Flight Center, Huntsville, Alabama 35812 (United States)

    2010-11-15

    A variation of a hanging pendulum thrust stand capable of measuring the performance of an electric thruster operating in the vertical orientation is presented. The vertical orientation of the thruster dictates that the thruster must be horizontally offset from the pendulum pivot arm, necessitating the use of a counterweight system to provide a neutrally stable system. Motion of the pendulum arm is transferred through a balance mechanism to a secondary arm on which deflection is measured. A noncontact light-based transducer is used to measure displacement of the secondary beam. The members experience very little friction, rotating on twisting torsional pivots with oscillatory motion attenuated by a passive, eddy-current damper. Displacement is calibrated using an in situ thrust calibration system. Thermal management and self-leveling systems are incorporated to mitigate thermal and mechanical drifts. Gravitational force and torsional spring constants associated with flexure pivots provide restoring moments. An analysis of the design indicates that the thrust measurement range spans roughly four decades, with the stand capable of measuring thrust up to 12 N for a 200 kg thruster and up to approximately 800 mN for a 10 kg thruster. Data obtained from calibration tests performed using a 26.8 lbm simulated thruster indicated a resolution of 1 mN on 100 mN level thrusts, while those tests conducted on a 200 lbm thruster yielded a resolution of roughly 2.5 mN at thrust levels of 0.5 N and greater.

  1. Full Flight Envelope Direct Thrust Measurement on a Supersonic Aircraft

    Science.gov (United States)

    Conners, Timothy R.; Sims, Robert L.

    1998-01-01

    Direct thrust measurement using strain gages offers advantages over analytically-based thrust calculation methods. For flight test applications, the direct measurement method typically uses a simpler sensor arrangement and minimal data processing compared to analytical techniques, which normally require costly engine modeling and multisensor arrangements throughout the engine. Conversely, direct thrust measurement has historically produced less than desirable accuracy because of difficulty in mounting and calibrating the strain gages and the inability to account for secondary forces that influence the thrust reading at the engine mounts. Consequently, the strain-gage technique has normally been used for simple engine arrangements and primarily in the subsonic speed range. This paper presents the results of a strain gage-based direct thrust-measurement technique developed by the NASA Dryden Flight Research Center and successfully applied to the full flight envelope of an F-15 aircraft powered by two F100-PW-229 turbofan engines. Measurements have been obtained at quasi-steady-state operating conditions at maximum non-augmented and maximum augmented power throughout the altitude range of the vehicle and to a maximum speed of Mach 2.0 and are compared against results from two analytically-based thrust calculation methods. The strain-gage installation and calibration processes are also described.

  2. Thrust Stand for Vertically Oriented Electric Propulsion Performance Evaluation

    Science.gov (United States)

    Moeller, Trevor; Polzin, Kurt A.

    2010-01-01

    A variation of a hanging pendulum thrust stand capable of measuring the performance of an electric thruster operating in the vertical orientation is presented. The vertical orientation of the thruster dictates that the thruster must be horizontally offset from the pendulum pivot arm, necessitating the use of a counterweight system to provide a neutrally-stable system. Motion of the pendulum arm is transferred through a balance mechanism to a secondary arm on which deflection is measured. A non-contact light-based transducer is used to measure displacement of the secondary beam. The members experience very little friction, rotating on twisting torsional pivots with oscillatory motion attenuated by a passive, eddy current damper. Displacement is calibrated using an in situ thrust calibration system. Thermal management and self-leveling systems are incorporated to mitigate thermal and mechanical drifts. Gravitational restoring force and torsional spring constants associated with flexure pivots provide restoring moments. An analysis of the design indicates that the thrust measurement range spans roughly four decades, with the stand capable of measuring thrust up to 12 N for a 200 kg thruster and up to approximately 800 mN for a 10 kg thruster. Data obtained from calibration tests performed using a 26.8 lbm simulated thruster indicated a resolution of 1 mN on 100 mN-level thrusts, while those tests conducted on 200 lbm thruster yielded a resolution of roughly 2.5 micro at thrust levels of 0.5 N and greater.

  3. Thrust stand for vertically oriented electric propulsion performance evaluation.

    Science.gov (United States)

    Moeller, Trevor; Polzin, Kurt A

    2010-11-01

    A variation of a hanging pendulum thrust stand capable of measuring the performance of an electric thruster operating in the vertical orientation is presented. The vertical orientation of the thruster dictates that the thruster must be horizontally offset from the pendulum pivot arm, necessitating the use of a counterweight system to provide a neutrally stable system. Motion of the pendulum arm is transferred through a balance mechanism to a secondary arm on which deflection is measured. A noncontact light-based transducer is used to measure displacement of the secondary beam. The members experience very little friction, rotating on twisting torsional pivots with oscillatory motion attenuated by a passive, eddy-current damper. Displacement is calibrated using an in situ thrust calibration system. Thermal management and self-leveling systems are incorporated to mitigate thermal and mechanical drifts. Gravitational force and torsional spring constants associated with flexure pivots provide restoring moments. An analysis of the design indicates that the thrust measurement range spans roughly four decades, with the stand capable of measuring thrust up to 12 N for a 200 kg thruster and up to approximately 800 mN for a 10 kg thruster. Data obtained from calibration tests performed using a 26.8 lbm simulated thruster indicated a resolution of 1 mN on 100 mN level thrusts, while those tests conducted on a 200 lbm thruster yielded a resolution of roughly 2.5 mN at thrust levels of 0.5 N and greater.

  4. 14 CFR 33.8 - Selection of engine power and thrust ratings.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Selection of engine power and thrust... thrust ratings. (a) Requested engine power and thrust ratings must be selected by the applicant. (b) Each selected rating must be for the lowest power or thrust that all engines of the same type may be expected to...

  5. Evolution of the Puente Hills Thrust Fault

    Science.gov (United States)

    Bergen, K. J.; Shaw, J. H.; Dolan, J. F.

    2013-12-01

    This study aims to assess the evolution of the blind Puente Hills thrust fault system (PHT) by determining its age of initiation, lateral propagation history, and changes in slip rate over time. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. The PHT is comprised of three fault segments: the Los Angeles (LA), Santa Fe Springs (SFS), and Coyote Hills (CH). The LA and SFS segments are characterized by growth stratigraphy where folds formed by uplift on the fault segments have been continually buried by sediment from the Los Angeles and San Gabriel rivers. The CH segment has developed topography and is characterized by onlapping growth stratigraphy. This depositional setting gives us the unique opportunity to measure uplift on the LA and SFS fault segments, and minimum uplift on the CH fault segment, as the difference in sediment thicknesses across the buried folds. We utilize depth converted oil industry seismic reflection data to image the fold geometries. Identifying time-correlative stratigraphic markers for slip rate determination in the basin has been a problem for researchers in the past, however, as the faunal assemblages observed in wells are time-transgressive by nature. To overcome this, we utilize the sequence stratigraphic model and well picks of Ponti et al. (2007) as a basis for mapping time-correlative sequence boundaries throughout our industry seismic reflection data from the present to the Pleistocene. From the Pleistocene to Miocene we identify additional sequence boundaries in our seismic reflection data from imaged sequence geometries and by correlating industry well formation tops. The sequence and formation top picks are then used to build 3-dimensional surfaces in the modeling program Gocad. From these surfaces we measure the change in thicknesses across the folds to obtain uplift rates between each sequence boundary. Our results show three distinct phases of

  6. Thrust calculation of electric solar wind sail by particle-in-cell simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hoshi, Kento [Kyoto Univ. (Japan). Dept. of Electrical Engineering; Kojima, Hirotsugu; Yamakawa, Hiroshi [Kyoto Univ. (Japan). Research Inst. for Sustainable Humanosphere; Muranaka, Takanobu [Chukyo Univ., Nagoya (Japan). Dept. of Electrical Engineering

    2016-07-01

    In this study, thrust characteristics of an electric solar wind sail were numerically evaluated using full threedimensional particle-in-cell (PIC) simulation. The thrust obtained from the PIC simulation was lower than the thrust estimations obtained in previous studies. The PIC simulation indicated that ambient electrons strongly shield the electrostatic potential of the tether of the sail, and the strong shield effect causes a greater thrust reduction than has been obtained in previous studies. Additionally, previous expressions of the thrust estimation were modified by using the shielded potential structure derived from the present simulation results. The modified thrust estimation agreed very well with the thrust obtained from the PIC simulation.

  7. Bilateral and multiple cavitation sounds during upper cervical thrust manipulation

    Directory of Open Access Journals (Sweden)

    Dunning James

    2013-01-01

    Full Text Available Abstract Background The popping produced during high-velocity, low-amplitude (HVLA thrust manipulation is a common sound; however to our knowledge, no study has previously investigated the location of cavitation sounds during manipulation of the upper cervical spine. The primary purpose was to determine which side of the spine cavitates during C1-2 rotatory HVLA thrust manipulation. Secondary aims were to calculate the average number of pops, the duration of upper cervical thrust manipulation, and the duration of a single cavitation. Methods Nineteen asymptomatic participants received two upper cervical thrust manipulations targeting the right and left C1-2 articulation, respectively. Skin mounted microphones were secured bilaterally over the transverse process of C1, and sound wave signals were recorded. Identification of the side, duration, and number of popping sounds were determined by simultaneous analysis of spectrograms with audio feedback using custom software developed in Matlab. Results Bilateral popping sounds were detected in 34 (91.9% of 37 manipulations while unilateral popping sounds were detected in just 3 (8.1% manipulations; that is, cavitation was significantly (P Conclusions Cavitation was significantly more likely to occur bilaterally than unilaterally during upper cervical HVLA thrust manipulation. Most subjects produced 3–4 pops during a single rotatory HVLA thrust manipulation targeting the right or left C1-2 articulation; therefore, practitioners of spinal manipulative therapy should expect multiple popping sounds when performing upper cervical thrust manipulation to the atlanto-axial joint. Furthermore, the traditional manual therapy approach of targeting a single ipsilateral or contralateral facet joint in the upper cervical spine may not be realistic.

  8. Bilateral and multiple cavitation sounds during upper cervical thrust manipulation.

    Science.gov (United States)

    Dunning, James; Mourad, Firas; Barbero, Marco; Leoni, Diego; Cescon, Corrado; Butts, Raymond

    2013-01-15

    The popping produced during high-velocity, low-amplitude (HVLA) thrust manipulation is a common sound; however to our knowledge, no study has previously investigated the location of cavitation sounds during manipulation of the upper cervical spine. The primary purpose was to determine which side of the spine cavitates during C1-2 rotatory HVLA thrust manipulation. Secondary aims were to calculate the average number of pops, the duration of upper cervical thrust manipulation, and the duration of a single cavitation. Nineteen asymptomatic participants received two upper cervical thrust manipulations targeting the right and left C1-2 articulation, respectively. Skin mounted microphones were secured bilaterally over the transverse process of C1, and sound wave signals were recorded. Identification of the side, duration, and number of popping sounds were determined by simultaneous analysis of spectrograms with audio feedback using custom software developed in Matlab. Bilateral popping sounds were detected in 34 (91.9%) of 37 manipulations while unilateral popping sounds were detected in just 3 (8.1%) manipulations; that is, cavitation was significantly (P thrust manipulation was 3.57 (95% CI: 3.19, 3.94) and the mean number of pops per subject following both right and left C1-2 thrust manipulations was 6.95 (95% CI: 6.11, 7.79). The mean duration of a single audible pop was 5.66 ms (95% CI: 5.36, 5.96) and the mean duration of a single manipulation was 96.95 ms (95% CI: 57.20, 136.71). Cavitation was significantly more likely to occur bilaterally than unilaterally during upper cervical HVLA thrust manipulation. Most subjects produced 3-4 pops during a single rotatory HVLA thrust manipulation targeting the right or left C1-2 articulation; therefore, practitioners of spinal manipulative therapy should expect multiple popping sounds when performing upper cervical thrust manipulation to the atlanto-axial joint. Furthermore, the traditional manual therapy approach of

  9. Practical compensation for nonlinear dynamic thrust measurement system

    Directory of Open Access Journals (Sweden)

    Chen Lin

    2015-04-01

    Full Text Available The real dynamic thrust measurement system usually tends to be nonlinear due to the complex characteristics of the rig, pipes connection, etc. For a real dynamic measuring system, the nonlinearity must be eliminated by some adequate methods. In this paper, a nonlinear model of dynamic thrust measurement system is established by using radial basis function neural network (RBF-NN, where a novel multi-step force generator is designed to stimulate the nonlinearity of the system, and a practical compensation method for the measurement system using left inverse model is proposed. Left inverse model can be considered as a perfect dynamic compensation of the dynamic thrust measurement system, and in practice, it can be approximated by RBF-NN based on least mean square (LMS algorithms. Different weights are set for producing the multi-step force, which is the ideal input signal of the nonlinear dynamic thrust measurement system. The validity of the compensation method depends on the engine’s performance and the tolerance error 0.5%, which is commonly demanded in engineering. Results from simulations and experiments show that the practical compensation using left inverse model based on RBF-NN in dynamic thrust measuring system can yield high tracking accuracy than the conventional methods.

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

    Science.gov (United States)

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

    1988-01-01

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

  11. Wedge equilibrium in fold-and-thrust belts: prediction of out-of-sequence thrusting based on sandbox experiments and natural examples

    NARCIS (Netherlands)

    Nieuwland, D.A.; Leutscher, J.H.; Gast, J.

    Thrust tectonics are dealt with on the basis of primarily experiments focusing on the dynamics of a developing thrust belt and on understanding and predicting normal-sequence and out-of-sequence thrusting. Field examples are presented in addition to the examples of sandbox-model experiments. The

  12. Wedge equilibrium in fold-and-thrust belts: prediction of out-of-sequence thrusting based on sandbox experiments and natural examples

    NARCIS (Netherlands)

    Nieuwland, D.A.; Leutscher, J.H.; Gast, J.

    2000-01-01

    Thrust tectonics are dealt with on the basis of primarily experiments focusing on the dynamics of a developing thrust belt and on understanding and predicting normal-sequence and out-of-sequence thrusting. Field examples are presented in addition to the examples of sandbox-model experiments. The res

  13. Sandbox modeling of evolving thrust wedges with different preexisting topographic relief: Implications for the Longmen Shan thrust belt, eastern Tibet

    Science.gov (United States)

    Sun, Chuang; Jia, Dong; Yin, Hongwei; Chen, Zhuxin; Li, Zhigang; Shen, Li; Wei, Dongtao; Li, Yiquan; Yan, Bin; Wang, Maomao; Fang, Shaozhi; Cui, Jian

    2016-06-01

    To understand the effects of substantial topographic relief on deformation localization in the seismically active mountains, like the Longmen Shan thrust belt in the eastern Tibet, sandbox experiments were performed based on the framework of the critical taper theory. First, a reference experiment revealed that the critical taper angle was 12° for our experimental materials. Subsequently, different proto wedges (subcritical (6° in taper angle), critical (12°), and supercritical (20°)) were introduced to cover the range of natural topographic relief, and we used two setups: setup A considered only across-strike topographic relief, whereas setup B investigated along-strike segmentation of topography, consist of two adjacent proto wedges. In all experiments, thrust wedges grew by in-sequence accretion of thrust sheets. Setup A revealed an alternating mode of slip partitioning on the accreted thrusts, with large-displacement thrust and small-displacement thrust developing in turn. And contrasting wedge evolutions occurred according to whether the proto wedge was subcritical or critical-supercritical. In setup B, the differential deformation along the strike produced transverse structures such as tear fault and lateral ramp during frontal accretion. The observed tear fault and its associated thrust system resemble the seismogenic fault system of the 2008 Mw7.9 Wenchuan earthquake. Our experimental results could also explain first-order deformation features observed in the Longmen Shan. Consequently, we conclude that topographic features, including topographic relief across the range and along-strike segmentation of topography, contribute significantly to the kinematics and deformation localization in such active mountains.

  14. TRANSIENT TEMPERATURE FIELD IN ACTIVE THRUST MAGNETIC BEARING

    Institute of Scientific and Technical Information of China (English)

    Sun Shouqun; Geng Haipeng; Guo Keqian

    2005-01-01

    A transient temperature field model in a thrust magnetic bearing is built in which the heat resources come mainly from the eddy-current loss of solid cores and the copper loss of coils. The transient temperature field, system temperature rise and the thermo-equilibrium state during the rotor starting-up are calculated considering only the copper loss and the eddy-current loss. The numerical results indicate that the temperatures in coils and in magnets rise rapidly, their thermo-equilibrium states are formed within a short time. The temperatures in a thrust-disk and in a rotor rise slowly, their thermo-equilibrium states are formed after a long period time. The temperatures of the thrust-disk and the rotor are far higher than the temperatures of coils and/or magnets after the thermo-equilibrium state has come into being.

  15. Subleading Corrections To Thrust Using Effective Field Theory

    CERN Document Server

    Freedman, Simon M

    2013-01-01

    We calculate the subleading corrections to the thrust rate using Soft-Collinear Effective Theory to factorize the rate and match onto jet and soft operators that describe the degrees of freedom of the relevant scales. We work in the perturbative regime where all the scales are well above \\Lambda_QCD. The thrust rate involves an incomplete sum over final states that is enforced by a measurement operator. Subleading corrections require matching onto not only the higher dimensional dijet operators, but also matching onto subleading measurement operators in the effective theory. We explicitly show how to factorize the O(\\alpha_s \\tau) thrust rate into a hard function multiplied by the convolution of the vacuum expectation value of jet and soft operators. Our approach can be generalized to other jet shapes and rates.

  16. Separability of drag and thrust in undulatory animals and machines

    CERN Document Server

    Bale, Rahul; Neveln, Izaak D; Bhalla, Amneet Pal Singh; MacIver, Malcolm A; Patankar, Neelesh A

    2014-01-01

    For nearly a century, researchers have tried to understand the swimming of aquatic animals in terms of a balance between the forward thrust from swimming movements and drag on the body. Prior approaches have failed to provide a separation of these two forces for undulatory swimmers such as lamprey and eels, where most parts of the body are simultaneously generating drag and thrust. We nonetheless show that this separation is possible, and delineate its fundamental basis in undulatory swimmers. Our approach unifies a vast diversity of undulatory aquatic animals (anguilliform, sub-carangiform, gymnotiform, bal- istiform, rajiform) and provides design principles for highly agile bioinspired underwater vehicles. This approach has practical utility within biology as well as engineering. It is a predictive tool for use in understanding the role of the mechanics of movement in the evolutionary emergence of morphological features relating to locomotion. For example, we demonstrate that the drag-thrust separation fram...

  17. Parametric study of thermal behavior of thrust chamber cooling channels

    Directory of Open Access Journals (Sweden)

    Karima E. Amori

    2007-01-01

    Full Text Available A numerical investigation is adopted for two dimensional thermal analysis of rocket thrust chamber wall (RL10, employing finite difference model with iterative scheme (implemented under relaxation factor of 0.9 for convergence to compute temperature distribution within thrust chamber wall (which is composed of Nickel and Copper layers. The analysis is conducted for different boundary conditions: only convection boundary conditions then combined radiation, convection boundary conditions also for different aspect ratio (AR of cooling channel. The results show that Utilizing cooling channels of high aspect ratio leads to decrease in temperature variation across thrust chamber wall, while no effects on heat transferred to the coolant is indicated. The radiation has a considerable effect on the computed wall temperature values.

  18. Design and Fabrication of the Large Thrust Force Piezoelectric Actuator

    Directory of Open Access Journals (Sweden)

    Shyang-Jye Chang

    2013-01-01

    Full Text Available This paper presents a novel piezoelectric actuator containing double pushers. By using finite element analysis software, this study simulated the vibration mode and amplitude of piezoelectric actuators. The Taguchi method was used to design the parameters of piezoelectric actuators including length, width, height, and electrodes setting. This paper also presents a discussion regarding the influence that the design parameters had on the actuator amplitudes. Based on optimal design parameters, a novel piezoelectric actuator containing double pushers is produced and some thrust tests are also carried out. From the experiment results, the piezoelectric actuator containing double pushers can provide a greater thrust force than that of traditional actuators containing a single pusher as the preload is greater. Comparing with the traditional actuators, the thrust force of new actuator can be increased by 48% with the double preload.

  19. Methods for determining atypical gate valve thrust requirements

    Energy Technology Data Exchange (ETDEWEB)

    Steele, R. Jr.; Watkins, J.C.; DeWall, K.G. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others

    1995-04-01

    Evaluating the performance of rising stem, wedge type, gate valves used in nuclear power plant is not a problem when the valves can be design-basis tested and their operability margins determined diagnostically. The problem occurs when they cannot be tested because of plant system limitations or when they can be tested only at some less-than-design-basis condition. To evaluate the performance of these valves requires various analytical and/or extrapolation methods by which the design-basis stem thrust requirement can be determined. This has been typically accomplished with valve stem thrust models used to calculate the requirements or by extrapolating the results from a less-than-design-basis test. The stem thrust models used by the nuclear industry to determine the opening or closing stem thrust requirements for these gate valves have generally assumed that the highest load the valve experiences during closure (but before seating) is at flow isolation and during unwedging or before flow initiation in the opening direction. However, during full-scale valve testing conducted for the USNRC, several of the valves produced stem thrust histories that showed peak closing stem forces occurring before flow isolation in the closing direction and after flow initiation in the opening direction. All of the valves that exhibited this behavior in the closing direction also showed signs of internal damage. Initially, we dismissed the early peak in the closing stem thrust requirement as damage-induced and labeled it nonpredictable behavior. Opening responses were not a priority in our early research, so that phenomenon was set aside for later evaluation.

  20. Varus Thrust and Incident and Progressive Knee Osteoarthritis.

    Science.gov (United States)

    Sharma, Leena; Chang, Alison H; Jackson, Rebecca D; Nevitt, Michael; Moisio, Kirsten C; Hochberg, Marc; Eaton, Charles; Kwoh, C Kent; Almagor, Orit; Cauley, Jane; Chmiel, Joan S

    2017-08-03

    To determine if varus thrust, bowing-out of the knee during gait, i.e., the first appearance or worsening of varus alignment during stance, is associated with incident and progressive knee osteoarthritis (OA), we undertook an Osteoarthritis Initiative ancillary study. We further considered hypothesized associations adjusted for static alignment, anticipating some attenuation. 2-3 trained examiners/site at 4 sites observed gait. In eligible knees, incident OA was analyzed as subsequent incident KL≥2, whole and partial-grade medial joint space narrowing (JSN), and annualized loss of joint space width (JSW), and progression as medial JSN and JSW loss. Outcomes were assessed over up to 7 years of follow-up. Analyses were knee-level, using multivariable logistic and linear regression with GEE to account for between-limb correlation. The incident OA sample included 4187 knees/2610 persons; the progression sample included 3421 knees/2284 persons. In knees with OA, thrust was associated with progression by each outcome adjusting for age, gender, BMI, and pain. In knees without OA, varus thrust was not associated with incident OA or other outcomes. After adjustment for alignment, the thrust/progression association was attenuated but an independent association persisted for partial grade JSN and JSW loss outcome models. WOMAC Pain and alignment were consistently associated with all outcomes. Within the stratum of varus knees, thrust was associated with an increased risk of progression. Varus thrust visualized during gait is associated with knee OA progression and should be a target of intervention development. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Robotic Pectoral Fin Thrust Vectoring Using Weighted Gait Combinations

    Directory of Open Access Journals (Sweden)

    John S. Palmisano

    2012-01-01

    Full Text Available A method was devised to vector propulsion of a robotic pectoral fin by means of actively controlling fin surface curvature. Separate flapping fin gaits were designed to maximize thrust for each of three different thrust vectors: forward, reverse, and lift. By using weighted combinations of these three pre-determined main gaits, new intermediate hybrid gaits for any desired propulsion vector can be created with smooth transitioning between these gaits. This weighted gait combination (WGC method is applicable to other difficult-to-model actuators. Both 3D unsteady computational fluid dynamics (CFD and experimental results are presented.

  2. Problems of millipound thrust measurement. The "Hansen Suspension"

    Energy Technology Data Exchange (ETDEWEB)

    Carta, David G.

    2014-03-31

    Considered in detail are problems which led to the need and use of the 'Hansen Suspension'. Also discussed are problems which are likely to be encountered in any low level thrust measuring system. The methods of calibration and the accuracies involved are given careful attention. With all parameters optimized and calibration techniques perfected, the system was found capable of a resolution of 10 {mu} lbs. A comparison of thrust measurements made by the 'Hansen Suspension' with measurements of a less sophisticated device leads to some surprising results.

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

    Science.gov (United States)

    Robinson, Delores M.; Pearson, Ofori N.

    2013-01-01

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

  4. Tectonothermal history of an exhumed thrust-sheet-top basin: An example from the south Pyrenean thrust belt

    Science.gov (United States)

    Labaume, Pierre; Meresse, Florian; Jolivet, Marc; Teixell, Antonio; Lahfid, Abdeltif

    2016-05-01

    This paper presents a new balanced structural cross section of the Jaca thrust-sheet-top basin of the southern Pyrenees combined with paleothermometry and apatite fission track (AFT) thermochronology data. The cross section, based on field data and interpretation of industrial seismic reflection profiles, allows refinement of previous interpretations of the south directed thrust system, involving the identification of new thrust faults, and of the kinematic relationships between basement and cover thrusts from the middle Eocene to the early Miocene. AFT analysis shows a southward decrease in the level of fission track resetting, from totally reset Paleozoic rocks and lower Eocene turbidites (indicative of heating to Tmax > ~120°C), to partially reset middle Eocene turbidites and no/very weak resetting in the upper Eocene-lower Oligocene molasse (Tmax < ~60°C). AFT results indicate a late Oligocene-early Miocene cooling event throughout the Axial Zone and Jaca Basin. Paleomaximum temperatures determined by vitrinite reflectance measurements and Raman spectroscopy of carbonaceous material reach up to ~240°C at the base of the turbidite succession. Inverse modeling of AFT and vitrinite reflectance data with the QTQt software for key samples show compatibility between vitrinite-derived Tmax and the AFT reset level for most of the samples. However, they also suggest that the highest temperatures determined in the lowermost turbidites correspond to a thermal anomaly rather than burial heating, possibly due to fluid circulation during thrust activity. From these results, we propose a new sequential restoration of the south Pyrenean thrust system propagation and related basin evolution.

  5. 中高层护理管理者组织变革领导力研究现状%Research status of organizational change leadership of the upper-and mid-level nursing manager

    Institute of Scientific and Technical Information of China (English)

    吕娇; 谭洁; 王建荣; 黄叶莉; 毛美琪; 林欢

    2015-01-01

    Based on the conception analysis of the organizational change leadership of the upper-and mid-level nursing manager,this review described connovations of the organizational change leadership and its applications in nursing field at home and abroad,and pointed out the current research status,limitations and the inspirations we got,so as to provide references for promotion and evaluation of the upper-and midlevel nursing manager's organizational change leadership.%在对护理中高层管理者的组织变革领导力进行概念分析的基础上,阐述了国内外组织变革领导力的内涵及在护理领域的应用,并指出目前研究现状和不足以及给我们的启示,以期为护理中高层管理者组织变革领导力的提升与评价提供参考依据.

  6. Critical Pressures of the Thrust Bearing Using a Magnetic Fluid

    OpenAIRE

    長屋, 幸助; 武田, 定彦; 佐藤, 淳; 井開, 重男; 関口, 肇; 斉藤, 登

    1990-01-01

    This paper proposes a thrust bearing lubricated by a magnetic fluid under a magnetic field. The critical pressures of the bearing versus the magnitude of the magnetic flux densities have been investigated experimentally. It is clarified that the critical pressures of the proposed bearing are larger than those of the normal lubricant bearing under high speeds.

  7. Structural setting of the Apennine-Maghrebian thrust belt

    Institute of Scientific and Technical Information of China (English)

    PieroElter; MarioGrasso; MaurizioParotto; LivioVezzani

    2003-01-01

    The Apennine-Maghrebian fold-and-thrust belt devel-oped from the latest Cretaceous to Early Pleistocene at the subduction-collisional boundary between the Euro-pean and the westward-subducted Ionian and Adria plates. Large parts of the Mesozoic oceanic lithosphere were subducted during an Alpine phase from the Late Cretaceous to Middle Eocene. The chain developed through the deformation of major paleogeographic internal domains (tectono-sedimentary sequences of the Ligurian-Piedmont Ocean) and external domains (sedi-mentary sequences derived from the deformation of the continental Adria-African passive mareinL The continu-ity of the Apennine chain is abruptly interrupted in the Calabrian Arc by the extensive klippe of Kabylo-Calabrian crystalline exotic terranes, derived from deformation of the European passive margin.Major complexities (sharp deflections in the arcuate configuration of the thrust belt, out-of-sequence propagation of the thrusts) are referred to contrasting rheology and differential buoyancy of the subducted lithosphere (transitional from conti-nental to oceanic) and consequent differential roll-back of the Adria plate margin, and to competence contrasts in the Mesozoic stratigraphic sequences,where multiple décollement horizons at different stratigraphic levels may have favored significant differential shortening.From the Late Miocene, the geometry of the thrust belt was strongly modified by extensional fault-ing, volcanic activity, crustal thinning and formation of oceanic crust correlated with the development of the Tyrrhenian Basin.

  8. Measuring thrust and predicting trajectory in model rocketry

    CERN Document Server

    Courtney, Michael

    2009-01-01

    Methods are presented for measuring thrust using common force sensors and data acquisition to construct a dynamic force plate. A spreadsheet can be used to compute trajectory by integrating the equations of motion numerically. These techniques can be used in college physics courses, and have also been used with high school students concurrently enrolled in algebra 2.

  9. A Theoretical Study of Two Stage Thrust Augmenting Ejectors,

    Science.gov (United States)

    1984-11-01

    been found to increase the availability of thrust experimentally (Morrison 1942), and analitically (Nagaraja et al. 1973), no further work to the best...Applied Mechanics Reviews The John Crerar Library The Chemical Abstracts Service Allis Chalmers Corporation, Library Kentex Research Library United

  10. Engineering Research, Development and Technology, FY95: Thrust area report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the knowledge base, process technologies, specialized equipment, tools and facilities to support current and future LLNL programs. Engineering`s efforts are guided by a strategy that results in dual benefit: first, in support of Department of Energy missions, such as national security through nuclear deterrence; and second, in enhancing the nation`s economic competitiveness through their collaboration with US industry in pursuit of the most cost-effective engineering solutions to LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) identify key technologies relevant to LLNL programs where they can establish unique competencies, and (2) conduct high-quality research and development to enhance their capabilities and establish themselves as the world leaders in these technologies. To focus Engineering`s efforts, technology thrust areas are identified and technical leaders are selected for each area. The thrust areas are comprised of integrated engineering activities, staffed by personnel from the nine electronics and mechanical engineering divisions, and from other LLNL organizations. This annual report, organized by thrust area, describes Engineering`s activities for fiscal year 1995. The report provides timely summaries of objectives methods, and key results from eight thrust areas: computational electronics and electromagnetics; computational mechanics; microtechnology; manufacturing technology; materials science and engineering; power conversion technologies; nondestructive evaluation; and information engineering.

  11. Frictional Characteristics of Thrust Bearing in Scroll Compressor

    Science.gov (United States)

    Sato, Hajime; Itoh, Takahide; Kobayashi, Hiroyuki

    This paper presents frictional characteristics of thrust bearing in scroll compressor focusing on the behavior of sliding portion which affects the generation of oil film. The coefficient of friction and tilt angle of sliding portion in the thrust bearing are obtained through both elemental friction test and cylinder pressure measurement of actual scroll compressor. Both tests showed that the coefficient of friction in low contact pressure rose with increase of tilt angle of sliding portion. The value of contact pressure which the coefficient of friction turns into increase was in agreement of the value which tilt angle become to increase. Numerical analysis using mixed lubrication theory was also performed. Analytical result indicated the same characteristics as the experiments, and the correlation between the coefficient of friction and the behavior of sliding portion was confirmed. Based on the experimental and the analytical results obtained here, the optimization of thrust bearing for commercial scroll compressor was applied. 2% improvement of total efficiency in rated condition was archived by optimization of thrust bearing.

  12. Minimum Thrust Load Control for Floating Wind Turbine

    DEFF Research Database (Denmark)

    Christiansen, Søren; Bak, Thomas; Knudsen, Torben

    2012-01-01

    presents a new minimum thrust control strategy capable of stabilizing a floating wind turbine. The new control strategy explores the freedom of variable generator speed above rated wind speed. A comparison to the traditional constant speed strategy, shows improvements in structural fore-aft oscillations...

  13. Development Status of High-Thrust Density Electrostatic Engines

    Science.gov (United States)

    Patterson, Michael J.; Haag, Thomas W.; Foster, John E.; Young, Jason A.; Crofton, Mark W.

    2017-01-01

    Ion thruster technology offers the highest performance and efficiency of any mature electric propulsion thruster. It has by far the highest demonstrated total impulse of any technology option, demonstrated at input power levels appropriate for primary propulsion. It has also been successfully implemented for primary propulsion in both geocentric and heliocentric environments, with excellent ground/in-space correlation of both its performance and life. Based on these attributes there is compelling reasoning to continue the development of this technology: it is a leading candidate for high power applications; and it provides risk reduction for as-yet unproven alternatives. As such it is important that the operational limitations of ion thruster technology be critically examined and in particular for its application to primary propulsion its capabilities relative to thrust the density and thrust-to-power ratio be understood. This publication briefly addresses some of the considerations relative to achieving high thrust density and maximizing thrust-to-power ratio with ion thruster technology, and discusses the status of development work in this area being executed under a collaborative effort among NASA Glenn Research Center, the Aerospace Corporation, and the University of Michigan.

  14. Separability of drag and thrust in undulatory animals and machines.

    Science.gov (United States)

    Bale, Rahul; Shirgaonkar, Anup A; Neveln, Izaak D; Bhalla, Amneet Pal Singh; MacIver, Malcolm A; Patankar, Neelesh A

    2014-12-10

    For nearly a century, researchers have tried to understand the swimming of aquatic animals in terms of a balance between the forward thrust from swimming movements and drag on the body. Prior approaches have failed to provide a separation of these two forces for undulatory swimmers such as lamprey and eels, where most parts of the body are simultaneously generating drag and thrust. We nonetheless show that this separation is possible, and delineate its fundamental basis in undulatory swimmers. Our approach unifies a vast diversity of undulatory aquatic animals (anguilliform, sub-carangiform, gymnotiform, bal-istiform, rajiform) and provides design principles for highly agile bioinspired underwater vehicles. This approach has practical utility within biology as well as engineering. It is a predictive tool for use in understanding the role of the mechanics of movement in the evolutionary emergence of morphological features relating to locomotion. For example, we demonstrate that the drag-thrust separation framework helps to predict the observed height of the ribbon fin of electric knifefish, a diverse group of neotropical fish which are an important model system in sensory neurobiology. We also show how drag-thrust separation leads to models that can predict the swimming velocity of an organism or a robotic vehicle.

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

    Science.gov (United States)

    Leitner, Alfred

    1982-01-01

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

  16. THE EDDY LOSSES OF A MAGNETIC THRUST BEARING

    Institute of Scientific and Technical Information of China (English)

    徐华; 王艳

    2004-01-01

    Accurate calculations of losses associated with the operation of magnetic bearings are particularly important for high speed applications where the rotor losses are expected to be large and for some particular applications where even low power losses will be critical. Power losses in the magnetic thrust bearing is often neglected, but if there is misaligned in the rotor and bearing, the magnetic field in the thrust bearing is no longer axisymmetric one, or the dynamic control current in the winding is time dependent one, eddy currents are caused to flow inside the conducting material, then the power losses are very important for magnetic bearing design. This paper presents an analytical model of a thrust magnetic bearing, and the magnetic fields, forces and losses of thrust magnetic bearing are calculated. In the calculations the frequency of dynamic control current is up to 1000Hz, rotating speed is from 60rpm to 1200rpm, and the non-linearity of material is also taken into consideration. The results shows that if the magnetic field is not saturation, the eddy losses is proportional to dynamic control current frequency and a square function of dynamic control current, and also 5/2 power function of shaft's speed.

  17. Operant Control of Pathological Tongue Thrust in Spastic Cerebral Palsy.

    Science.gov (United States)

    Thompson, George A., Jr.

    1979-01-01

    The behavior modification procedure, carried out at mealtime with a ten-year-old retarded boy who had spastic cerebral palsy, consisted of differential reinforcement and punishment, and resulted in substantial decreases in tongue thrust (reverse swallowing) and food expulsion, and a large increase in observed chewing. (Author/DLS)

  18. A 10 nN resolution thrust-stand for micro-propulsion devices

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Subha; Courtney, Daniel G.; Shea, Herbert, E-mail: herbert.shea@epfl.ch [Microsystems for Space Technologies Laboratory (LMTS), Ecole Polytechnique Federale de Lausanne (EPFL), Neuchatel (Switzerland)

    2015-11-15

    We report on the development of a nano-Newton thrust-stand that can measure up to 100 μN thrust from different types of microthrusters with 10 nN resolution. The compact thrust-stand measures the impingement force of the particles emitted from a microthruster onto a suspended plate of size 45 mm × 45 mm and with a natural frequency over 50 Hz. Using a homodyne (lock-in) readout provides strong immunity to facility vibrations, which historically has been a major challenge for nano-Newton thrust-stands. A cold-gas thruster generating up to 50 μN thrust in air was first used to validate the thrust-stand. Better than 10 nN resolution and a minimum detectable thrust of 10 nN were achieved. Thrust from a miniature electrospray propulsion system generating up to 3 μN of thrust was measured with our thrust-stand in vacuum, and the thrust was compared with that computed from beam diagnostics, obtaining agreement within 50 nN to 150 nN. The 10 nN resolution obtained from this thrust-stand matches that from state-of-the-art nano-Newton thrust-stands, which measure thrust directly from the thruster by mounting it on a moving arm (but whose natural frequency is well below 1 Hz). The thrust-stand is the first of its kind to demonstrate less than 3 μN resolution by measuring the impingement force, making it capable of measuring thrust from different types of microthrusters, with the potential of easy upscaling for thrust measurement at much higher levels, simply by replacing the force sensor with other force sensors.

  19. A 10 nN resolution thrust-stand for micro-propulsion devices

    Science.gov (United States)

    Chakraborty, Subha; Courtney, Daniel G.; Shea, Herbert

    2015-11-01

    We report on the development of a nano-Newton thrust-stand that can measure up to 100 μN thrust from different types of microthrusters with 10 nN resolution. The compact thrust-stand measures the impingement force of the particles emitted from a microthruster onto a suspended plate of size 45 mm × 45 mm and with a natural frequency over 50 Hz. Using a homodyne (lock-in) readout provides strong immunity to facility vibrations, which historically has been a major challenge for nano-Newton thrust-stands. A cold-gas thruster generating up to 50 μN thrust in air was first used to validate the thrust-stand. Better than 10 nN resolution and a minimum detectable thrust of 10 nN were achieved. Thrust from a miniature electrospray propulsion system generating up to 3 μN of thrust was measured with our thrust-stand in vacuum, and the thrust was compared with that computed from beam diagnostics, obtaining agreement within 50 nN to 150 nN. The 10 nN resolution obtained from this thrust-stand matches that from state-of-the-art nano-Newton thrust-stands, which measure thrust directly from the thruster by mounting it on a moving arm (but whose natural frequency is well below 1 Hz). The thrust-stand is the first of its kind to demonstrate less than 3 μN resolution by measuring the impingement force, making it capable of measuring thrust from different types of microthrusters, with the potential of easy upscaling for thrust measurement at much higher levels, simply by replacing the force sensor with other force sensors.

  20. Performance of Simple Gas Foil Thrust Bearings in Air

    Science.gov (United States)

    Bruckner, Robert J.

    2012-01-01

    Foil bearings are self-acting hydrodynamics devices used to support high speed rotating machinery. The advantages that they offer to process fluid lubricated machines include: high rotational speed capability, no auxiliary lubrication system, non-contacting high speed operation, and improved damping as compared to rigid hydrodynamic bearings. NASA has had a sporadic research program in this technology for almost 6 decades. Advances in the technology and understanding of foil journal bearings have enabled several new commercial products in recent years. These products include oil-free turbochargers for both heavy trucks and automobiles, high speed electric motors, microturbines for distributed power generation, and turbojet engines. However, the foil thrust bearing has not received a complimentary level of research and therefore has become the weak link of oil-free turbomachinery. In an effort to both provide machine designers with basic performance parameters and to elucidate the underlying physics of foil thrust bearings, NASA Glenn Research Center has completed an effort to experimentally measure the performance of simple gas foil thrust bearing in air. The database includes simple bump foil supported thrust bearings with full geometry and manufacturing techniques available to the user. Test conditions consist of air at ambient pressure and temperatures up to 500 C and rotational speeds to 55,000 rpm. A complete set of axial load, frictional torque, and rotational speed is presented for two different compliant sub-structures and inter-pad gaps. Data obtained from commercially available foil thrust bearings both with and without active cooling is presented for comparison. A significant observation made possible by this data set is the speed-load capacity characteristic of foil thrust bearings. Whereas for the foil journal bearing the load capacity increases linearly with rotational speed, the foil thrust bearing operates in the hydrodynamic high speed limit. In

  1. Why style matters - uncertainty and structural interpretation in thrust belts.

    Science.gov (United States)

    Butler, Rob; Bond, Clare; Watkins, Hannah

    2016-04-01

    Structural complexity together with challenging seismic imaging make for significant uncertainty in developing geometric interpretations of fold and thrust belts. Here we examine these issues and develop more realistic approaches to building interpretations. At all scales, the best tests of the internal consistency of individual interpretations come from structural restoration (section balancing), provided allowance is made for heterogeneity in stratigraphy and strain. However, many existing balancing approaches give misleading perceptions of interpretational risk - both on the scale of individual fold-thrust (trap) structures and in regional cross-sections. At the trap-scale, idealised models are widely cited - fault-bend-fold, fault-propagation folding and trishear. These make entirely arbitrary choices for fault localisation and layer-by-layer deformation: precise relationships between faults and fold geometry are generally invalidated by real-world conditions of stratigraphic variation and distributed strain. Furthermore, subsurface predictions made using these idealisations for hydrocarbon exploration commonly fail the test of drilling. Rarely acknowledged, the geometric reliability of seismic images depends on the assigned seismic velocity model, which in turn relies on geological interpretation. Thus iterative approaches are required between geology and geophysics. The portfolio of commonly cited outcrop analogues is strongly biased to examples that simply conform to idealised models - apparently abnormal structures are rarely described - or even photographed! Insight can come from gravity-driven deep-water fold-belts where part of the spectrum of fold-thrust complexity is resolved through seismic imaging. This imagery shows deformation complexity in fold forelimbs and backlimbs. However, the applicability of these, weakly lithified systems to well-lithified successions (e.g. carbonates) of many foreland thrust belts remains conjectural. Examples of

  2. A Man With Two Burned Ears

    Institute of Scientific and Technical Information of China (English)

    范图雨

    2001-01-01

    Mr Smith was in troublethose days. He drove a car forMr Black, a rich business-man. He worked hard and theshopkeeper liked him. But hecouldn't work when he dranktoo much. And once he al-most fell into the river whenhe drove along the bridge. MrBlack became angry and wasgoing to send him away. Hehad a big family and wasafraid of that and promisedhe would stop drinking atonce. The man told him towait to be dealt with. OneMonday morning, Mr Smithcame into the office, with twobadly burned ears. “Whathappened to your ears?”asked Mr Black.

  3. Thrust Area Report, Engineering Research, Development and Technology

    Energy Technology Data Exchange (ETDEWEB)

    Langland, R. T.

    1997-02-01

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

  4. Frequency of varus and valgus thrust and factors associated with thrust presence in persons with or at higher risk of developing knee osteoarthritis.

    Science.gov (United States)

    Chang, Alison; Hochberg, Marc; Song, Jing; Dunlop, Dorothy; Chmiel, Joan S; Nevitt, Michael; Hayes, Karen; Eaton, Charles; Bathon, Joan; Jackson, Rebecca; Kwoh, C Kent; Sharma, Leena

    2010-05-01

    Varus thrust observed during gait has been shown to be associated with a 4-fold increase in the risk of medial knee osteoarthritis (OA) progression. Valgus thrust is believed to be less common than varus thrust; the prevalence of each is uncertain. Racial differences in risk factors may help explain variations in the natural history of knee OA. We undertook this study to determine the frequency of varus and valgus thrust in African Americans and Caucasians and to identify factors associated with thrust presence. The Osteoarthritis Initiative cohort includes men and women who have knee OA or are at increased risk of developing it. Trained examiners assessed thrust presence by gait observation. Logistic regression with generalized estimating equations was used to identify factors associated with thrust presence, and odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated. Compared with Caucasians, African Americans had lower odds of varus thrust, controlling for age, sex, body mass index (BMI), injury, surgery, disease severity, strength, pain, and alignment in persons without knee OA (adjusted OR 0.50 [95% CI 0.36, 0.72]) and in those with knee OA (adjusted OR 0.46 [95% CI 0.34, 0.61]). Also independently associated with varus thrust were age, sex, BMI, disease severity, strength, and alignment. The odds of valgus thrust were greater for African Americans than for Caucasians in persons without knee OA (adjusted OR 1.69 [95% CI 1.02, 2.80]) and in those with knee OA (adjusted OR 1.98 [95% CI 1.35, 2.91]). Also independently associated with valgus thrust were disease severity and malalignment. Compared with Caucasians, African Americans had lower odds of varus thrust and greater odds of valgus thrust. These findings may help explain the difference between these groups in the pattern of OA involvement at the knee.

  5. Frequency of Varus and Valgus Thrust and Factors Associated with Thrust Presence in Persons With or at Higher Risk for Knee Osteoarthritis

    Science.gov (United States)

    Chang, Alison; Hochberg, Marc; Song, Jing; Dunlop, Dorothy; Chmiel, Joan S.; Nevit, Michael; Hayes, Karen; Eaton, Charles; Bathon, Joan; Jackson, Rebecca; Kwoh, Kent; Sharma, Leena

    2010-01-01

    Varus thrust observed during gait has been shown to be associated with a 4-fold increase in the risk of medial knee osteoarthritis progression. Valgus thrust is believed less common than varus thrust; the prevalence of each is uncertain. Racial differences in risk factors may help explain variations in the natural history of knee osteoarthritis. Our objectives were: determine the frequency of varus and valgus thrust in African-Americans and Caucasians; identify factors associated with thrust presence. The Osteoarthritis Initiative cohort includes men and women with or at increased risk to develop knee osteoarthritis. Trained examiners assessed thrust presence by gait observation. Logistic regression with generalized estimating equations (GEE) was used to identify factors associated with thrust presence. African-Americans compared to Caucasians had lower odds of varus thrust, controlling for age, gender, BMI, injury, surgery, disease severity, strength, pain, and alignment in persons without (OR 0.50, 95% CI 0.36, 0.72) and with knee osteoarthritis (OR 0.46, 95% CI 0.34, 0.61). Also independently associated with varus thrust were age, gender, BMI, disease severity, strength, and alignment. The odds of valgus thrust were greater for African-Americans than Caucasians in persons without (OR 1.69, 95% CI 1.02, 2.80) and with knee osteoarthritis (OR 1.98, 95% CI 1.35, 2.91). Also independently associated with valgus thrust were disease severity and malalignment. African-Americans compared to Caucasians had lower odds of varus thrust and greater odds of valgus thrust, findings which may help explain the difference between these groups in the pattern of osteoarthritic involvement at the knee. PMID:20213800

  6. Syntectonic fluid-flow along thrust faults: Example of the South Pyrenean fold-and-thrust belt

    Science.gov (United States)

    Lacroix, B.; Travé, A.; Buatier, M.; Labaume, P.

    2012-04-01

    Estimation of the P-T conditions during evolution of sedimentary basins and characterization of petrophysical properties of fault zone are of major interests to oil companies, since they could allow to understand paleohydrological characteristics of potential reservoirs. In fold-and-thrust belts, faults are supposed to constitute channelized pathways for fluids coming from external, either deep or meteoric sources. However, the different available studies suggest that fluid flow through such discontinuities is not so evident. In order to constrain the paleofluid flow through the south Pyrenean fold-and-thrust belt we focus on thrust faults located at different structural levels. The microstructures observed in the different studied fault zones are similar and consist of pervasive cleavage, calcite shear and extension veins (respectively SV1 and EV1) and late dilatation veins (EV3). Thus, the presence of veins attests to the involvement of fluids during deformation. In order to characterize the nature and origin of fluid, petrological and geochemical (stable isotopes and trace elements) analyses were performed on calcite veins. The results suggest a high complexity in the hydrological behaviours of thrust faults evidencing a reservoir compartmentalization in the South-Pyrenean fold-and-thrust belt. In the southern part of the Axial Zone, different studies evidence the contribution of deep metamorphic water, probably derived from the Paleozoic basement, along Gavarnie related fault zones during deformation. In the Jaca basin, during the Monte Perdido thrust fault activity, we evidence the contribution of formation water. These data suggest a very closed hydrological fluid system where fluid flow didn't exceeded 70 m. In the other hand, the Jaca and Cotiella thrust faults located in the southern part of the basin, are characterized by a composite fluid-flow system. Indeed, stable isotopes and trace elements compositions of the first generation of calcite veins

  7. Thrust calculation of electric solar wind sail by particle-in-cell simulation

    OpenAIRE

    Hoshi, Kento; Kojima, Hirotsugu; Muranaka, Takanobu; YAMAKAWA, Hiroshi

    2016-01-01

    In this study, thrust characteristics of an electric solar wind sail were numerically evaluated using full three-dimensional particle-in-cell (PIC) simulation. The thrust obtained from the PIC simulation was lower than the thrust estimations obtained in previous studies. The PIC simulation indicated that ambient electrons strongly shield the electrostatic potential of the tether of the sail, and the strong shield effect causes a greater thrust reduction than has been obtaine...

  8. Transition from external imbricate zone to foreland thrust sheet in the Caledonides, N. Scandinavia

    Science.gov (United States)

    Rice, A. H. N.

    2010-05-01

    Thrust front geometries vary considerably between orogens, although erosion has usually removed external parts of the foreland thrust belt in older collision zones. This is the case in most of the Scandinavian Caledonides, where a well-defined basal decollement separates the nappe pile from the Autochthon. However, in both S and N Norway (E. Finnmark) thrust deformation dies out gradually towards the foreland. In Finnmark, the foreland thrust belt (Gaissa Thrust Belt) shows dominantly E-directed shortening. The internal part comprises the 50 km long (parallel to shortening) Munkavarri Imbricate Zone, with 50% shortening on 0.25-1.0 km spaced major imbricate thrusts. Minor thrusts/back-thrusts, are abundant near the basal decollement. Over ca. 12 km, major imbricate thrusts gradually cut up-section to lower stratigraphic levels, passing into tip-folds within the overlying Vuonjalrassa Thrust Sheet (20% shortening). The 10 km wide Låkkaskaidi Duplex (50% shortening), also underlies the Vuonjalrassa TS some 14 km to the foreland of the leading edge of the Munkavarri IZ. Stratigraphic overlap with the underlying Autochthon indicates that the Munkavarri IZ, Låkkaskaidi D and Vuonjalrassa TS were also transported en bloc towards the foreland by up to 25 km, along the Ruok'sadas Thrust. Below this, 20% shortening continues eastwards to the Hanadalen Thrust, in the footwall of which thrust ramps are no longer developed, although bedding-parallel slip continues further to the east. Sequentially, shortening in the Munkavarri IZ was likely of a continuously out-of-sequence nature, with all imbricate thrusts moving essentially together at the same time and older thrusts thus reaching higher stratigraphic levels as the basal decollement progressed towards the foreland. The decrease in shortening suggests a lower taper angle and/or faster thrust propagation. The cause of this is unknown, but much of the basal decollement under the Vuonjalrassa TS lies between pelitic rocks

  9. Interseismic Strain Accumulation Across Metropolitan Los Angeles: Puente Hills Thrust

    Science.gov (United States)

    Argus, D.; Liu, Z.; Heflin, M. B.; Moore, A. W.; Owen, S. E.; Lundgren, P.; Drake, V. G.; Rodriguez, I. I.

    2012-12-01

    Twelve years of observation of the Southern California Integrated GPS Network (SCIGN) are tightly constraining the distribution of shortening across metropolitan Los Angeles, providing information on strain accumulation across blind thrust faults. Synthetic Aperture Radar Interferometry (InSAR) and water well records are allowing the effects of water and oil management to be distinguished. The Mojave segment of the San Andreas fault is at a 25° angle to Pacific-North America plate motion. GPS shows that NNE-SSW shortening due to this big restraining bend is fastest not immediately south of the San Andreas fault across the San Gabriel mountains, but rather 50 km south of the fault in northern metropolitan Los Angeles. The GPS results we quote next are for a NNE profile through downtown Los Angeles. Just 2 mm/yr of shortening is being taken up across the San Gabriel mountains, 40 km wide (0.05 micro strain/yr); 4 mm/yr of shortening is being taken up between the Sierra Madre fault, at the southern front of the San Gabriel mountains, and South Central Los Angeles, also 40 km wide (0.10 micro strain/yr). We find shortening to be more evenly distributed across metropolitan Los Angeles than we found before [Argus et al. 2005], though within the 95% confidence limits. An elastic models of interseismic strain accumulation is fit to the GPS observations using the Back Slip model of Savage [1983]. Rheology differences between crystalline basement and sedimentary basin rocks are incorporated using the EDGRN/EDCMP algorithm of Wang et al. [2003]. We attempt to place the Back Slip model into the context of the Elastic Subducting Plate Model of Kanda and Simons [2010]. We find, along the NNE profile through downtown, that: (1) The deep Sierra Madre Thrust cannot be slipping faster than 2 mm/yr, and (2) The Puente Hills Thrust and nearby thrust faults (such as the upper Elysian Park Thrust) are slipping at 9 ±2 mm/yr beneath a locking depth of 12 ±5 km (95% confidence limits

  10. Recent movements along the Main Boundary Thrust of the Himalayas: Normal faulting in an over-critical thrust wedge?

    Science.gov (United States)

    Mugnier, Jean-Louis; Huyghe, Pascale; Chalaron, Edouard; Mascle, Georges

    1994-11-01

    The Main Boundary Thrust (MBT) is one of the major Himalayan thrusts occurring during the Cainozoic, and it is presently incorporated within the Himalayan thrust wedge (Lesser and Outer Himalayas) displaced above the Indian lithosphere. Nonetheless the MBT shows recent normal displacement along most of its length. We suggest that the orientation of the major principal stress within the Himalayan thrust wedge deviates significantly from the horizontal and when this deviation exceeds the dip of the vectors normal to back-tilted thrusts, the normal component of displacement may act along these faults. Steep north-dipping segments of the MBT therefore show a normal component of displacement if a geometrical definition is used, but they are faults in a compressional regime where the major principal stress axis has deviated from the horizontal. Micro-structural data recorded along the Surkhet-Ghorahi segment of the MBT are consistent with a strong deviation of the state of stress. The presence of such peculiar normal faulting along the MBT is used to calibrate the mechanical characteristics of the belt considered as a Coulomb wedge. The following characteristics are suggested: (a) very poor strength contrast between basal decollement and rocks in the wedge body, (b) a high pore fluid pressure ratio (probably close to 0.8-0.9) and a higher fluid pressure ratio (close to 1.0) along the active normal faults if a high internal friction angle (close to the Byerlee value) is considered. The strong deviation in principal stress direction may have recently increased, due to a taper of the Himalayan wedge exceeding the stability boundary and may be controlled by erosion and isostatic uplift rebound of the Himalayan range.

  11. Thrust Measurement of Dielectric Barrier Discharge (DBD) Plasma Actuators: New Anti-Thrust Hypothesis, Frequency Sweeps Methodology, Humidity and Enclosure Effects

    Science.gov (United States)

    Ashpis, David E.; Laun, Matthew C.

    2014-01-01

    We discuss thrust measurements of Dielectric Barrier Discharge (DBD) plasma actuators devices used for aerodynamic active flow control. After a review of our experience with conventional thrust measurement and significant non-repeatability of the results, we devised a suspended actuator test setup, and now present a methodology of thrust measurements with decreased uncertainty. The methodology consists of frequency scans at constant voltages. The procedure consists of increasing the frequency in a step-wise fashion from several Hz to the maximum frequency of several kHz, followed by frequency decrease back down to the start frequency of several Hz. This sequence is performed first at the highest voltage of interest, then repeated at lower voltages. The data in the descending frequency direction is more consistent and selected for reporting. Sample results show strong dependence of thrust on humidity which also affects the consistency and fluctuations of the measurements. We also observed negative values of thrust, or "anti-thrust", at low frequencies between 4 Hz and up to 64 Hz. The anti-thrust is proportional to the mean-squared voltage and is frequency independent. Departures from the parabolic anti-thrust curve are correlated with appearance of visible plasma discharges. We propose the anti-thrust hypothesis. It states that the measured thrust is a sum of plasma thrust and anti-thrust, and assumes that the anti-thrust exists at all frequencies and voltages. The anti-thrust depends on actuator geometry and materials and on the test installation. It enables the separation of the plasma thrust from the measured total thrust. This approach enables more meaningful comparisons between actuators at different installations and laboratories. The dependence on test installation was validated by surrounding the actuator with a grounded large-diameter metal sleeve. Strong dependence on humidity is also shown; the thrust significantly increased with decreasing humidity, e

  12. Using laterally compatible cross sections to infer fault growth and linkage models in foreland thrust belts

    Science.gov (United States)

    Watkins, Hannah; Butler, Robert W. H.; Bond, Clare E.

    2017-03-01

    We investigate changes in shortening, displacement and fold geometry to understand the detailed along-strike structural variation within fold-thrust belts, and infer thrust growth and linkage mechanisms. Field observations from the Vercors in SE France are used to characterise deformation style in the region. Parallel cross sections are constructed, analysed and used to create shortening and thrust displacement profiles from the northern to southern Vercors. Sections show changes in structural style and shortening accommodation from thrust-dominated in the north to fold-dominated in the south. The total shortening distance in the Vercors does not change significantly along strike (3400-4650 m), however displacements along individual thrust zones do vary significantly and displacement profiles show a range in displacement gradients (16-107 m/km). Despite relatively simple shortening patterns in the Vercors, sections show a more complex 3D internal structure of the fold-thrust belt. Thrust displacements and geometries suggest both large-scale thrust zones and small-scale thrusts are soft linked, transferring displacement along strike through transfer zones. Short, soft-linked thrust segments indicate an intermediate stage of thrust growth and linkage, well documented for normal fault systems, which form prior to the formation of thrust branches and hard-linked displacement transfer.

  13. 14 CFR Appendix I to Part 25 - Installation of an Automatic Takeoff Thrust Control System (ATTCS)

    Science.gov (United States)

    2010-01-01

    ... Appendix I to Part 25—Installation of an Automatic Takeoff Thrust Control System (ATTCS) I25.1General. (a... crew to increase thrust or power. I25.2Definitions. (a) Automatic Takeoff Thrust Control System (ATTCS... Control System (ATTCS) I Appendix I to Part 25 Aeronautics and Space FEDERAL AVIATION...

  14. 14 CFR 25.904 - Automatic takeoff thrust control system (ATTCS).

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Automatic takeoff thrust control system... Automatic takeoff thrust control system (ATTCS). Each applicant seeking approval for installation of an engine power control system that automatically resets the power or thrust on the operating engine(s)...

  15. 14 CFR 25.1155 - Reverse thrust and propeller pitch settings below the flight regime.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reverse thrust and propeller pitch settings... Powerplant Controls and Accessories § 25.1155 Reverse thrust and propeller pitch settings below the flight regime. Each control for reverse thrust and for propeller pitch settings below the flight regime must...

  16. Cenozoic thrust emplacement of a Devonian batholith, northeastern Brooks Range: Involvement of crystalline rocks in a foreland fold-and-thrust belt

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, W.K.; Hanks, C.L. (Univ. of Alaska, Fairbanks (USA))

    1990-05-01

    Involvement of crystalline rocks in thrusting near the foreland basin of a fold-and-thrust belt is relatively uncommon. In the northeastern Brooks Range, the Devonian Okpilak batholith was thrust northward and structurally elevated above adjacent foreland basin deposits during Cenozoic fold-and-thrust deformation. The batholith may have acted initially as a regional structural buttress, but a drop in the basal detachment surface to greater depth south of the batholith resulted in northward transport of the batholith. Shortening within the batholith was accommodated by (1) the development of discrete thrust slices bounded by ductile shear zones, (2) simple shear and development of penetrative mesoscopic and microscopic fabrics throughout the batholith, or both. The Mississippian Kayak Shale, a regional detachment horizon at the base of the overlying cover sequence, is depositionally thin or absent adjacent to the batholith. Thus, most of the cover sequence remained structurally coupled to the batholith during thrusting and was shortened by the development of penetrative structures.

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

    Science.gov (United States)

    Jolly, Byami; Whittaker, Alex; Lonergan, Lidia

    2015-04-01

    Gravity-driven seaward-verging thrusts, landward-verging back-thrusts and associated folds often characterize the slope and deepwater settings of passive margins. These structures, found in the 'toe-thrust' region of the system, exert a significant control on sediment gravity flows because they create and determine the location and configuration of sediment depocentres and transport systems. Consequently, a quantitative understanding of the interaction between sediment gravity flows and seabed topography is required to understand these systems effectively. Here we make quantitative measurements of the geomorphic response of submarine channels to growing tectonic structures with the aim of providing new constraints on the long-term erosional dynamics of submarine channel systems. This study exploits 3D seismic data in the outer toe-thrust region of the deepwater Niger Delta to analyze the interaction between Plio-Pleistocene channel systems and actively growing folds and thrusts. We mapped folds and thrusts from the seismic data and we used this data to reconstruct the history of fold growth. We then used the sea-bed seismic horizon to build a 50 m resolution Digital Elevation Model (DEM) of the sea floor in Arc-GIS. We extracted channel long- profiles across growing structures from the DEM, and made measurements of channel geometries at regular intervals along the channel length. This information was used to infer morphodyanamic processes that sculpted the channel systems through time, and to estimate the bed shear stresses and fluid velocities of typical flow events. The bathymetric long profiles of these channels are relatively linear with concavity that range from -0.08 to -0.34, and an average gradient of ~1o. Actively growing thrusts are typically associated with a local steepening in channel gradient by a factor of up to 3, and this effect extends 0.5 - 2 km upstream of the thrust. Within these knickzones, channel incision increases by approximately by a

  18. Engineering research, development and technology. Thrust area report, FY93

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the technical staff, tools, and facilities needed to support current and future LLNL programs. The efforts are guided by a dual-benefit research and development strategy that supports Department of Energy missions, such as national security through nuclear deterrence and economic competitiveness through partnerships with U.S. industry. This annual report, organized by thrust area, describes the activities for the fiscal year 1993. The report provides timely summaries of objectives, methods, and results from nine thrust areas for this fiscal year: Computational Electronics and Electromagnetics; Computational Mechanics; Diagnostics and Microelectronics; Fabrication Technology; Materials Science and Engineering; Power Conversion Technologies; Nondestructive Evaluation; Remote Sensing, Imaging, and Signal Engineering; and Emerging Technologies. Separate abstracts were prepared for 47 papers in this report.

  19. Minimum-fuel rocket trajectories involving intermediate-thrust arcs

    Science.gov (United States)

    Breakwell, J. V.; Dixon, J. F.

    1975-01-01

    The optimal trajectories in the neighborhood of an optimal intermediate-thrust arc are investigated for the minimum-fuel orbit rendezvous problem with fixed specific impulse. Since such an arc is singular, the thrust acceleration magnitude being the singular control component, a second-variation analysis leads to the identification of a field of neighboring, singular arcs in a state space of dimension four rather than six, provided that a suitable Jacobi condition is met. A given neighboring initial six-dimensional state vector does not generally lie on a neighboring singular arc, and junction onto the appropriate singular arc must be accomplished by a short period of strong variations in the acceleration. The neighboring singular arc meets the final condition in 4 dimensions, rather than 6 dimensions, and rendezvous must be completed by another, terminal short period of strong variations in the acceleration. Implications for midcourse guidance near a singular arc are discussed.

  20. A space tethered towing method using tension and platform thrusts

    Science.gov (United States)

    Meng, Zhongjie; Wang, Bingheng; Huang, Panfeng

    2017-01-01

    Orbit maneuver via tether is a promising countermeasure for space debris removal and satellite orbit transfer. A space tethered towing method is explored that utilizes thrust to fulfill transfer and bounded tension to stabilize tether heading. For this purpose, a time-energy optimal orbit is designed by Gauss pseudospectral method. The theoretical attitude commands are obtained by equilibria analysis. An effective attitude control strategy is presented where the commands are optimized first and then feedback controller is designed. To deal with the underactuated problem with tension constraint, hierarchical sliding mode theory is employed and an adaptive anti-windup module is added to mitigate the actuator saturation. Simulation results show that the target is towed effectively by the thrusts, and a smooth tracking for the commands of tether length and in-plane tether heading is guaranteed by the bounded tension. In addition, the designed controller also presents appreciable robustness to model error and determination error.

  1. Optimal specific wavelength for maximum thrust production in undulatory propulsion.

    Science.gov (United States)

    Nangia, Nishant; Bale, Rahul; Chen, Nelson; Hanna, Yohanna; Patankar, Neelesh A

    2017-01-01

    What wavelengths do undulatory swimmers use during propulsion? In this work we find that a wide range of body/caudal fin (BCF) swimmers, from larval zebrafish and herring to fully-grown eels, use specific wavelength (ratio of wavelength to tail amplitude of undulation) values that fall within a relatively narrow range. The possible emergence of this constraint is interrogated using numerical simulations of fluid-structure interaction. Based on these, it was found that there is an optimal specific wavelength (OSW) that maximizes the swimming speed and thrust generated by an undulatory swimmer. The observed values of specific wavelength for BCF animals are relatively close to this OSW. The mechanisms underlying the maximum propulsive thrust for BCF swimmers are quantified and are found to be consistent with the mechanisms hypothesized in prior work. The adherence to an optimal value of specific wavelength in most natural hydrodynamic propulsors gives rise to empirical design criteria for man-made propulsors.

  2. Optimization of Low-Thrust Spiral Trajectories by Collocation

    Science.gov (United States)

    Falck, Robert D.; Dankanich, John W.

    2012-01-01

    As NASA examines potential missions in the post space shuttle era, there has been a renewed interest in low-thrust electric propulsion for both crewed and uncrewed missions. While much progress has been made in the field of software for the optimization of low-thrust trajectories, many of the tools utilize higher-fidelity methods which, while excellent, result in extremely high run-times and poor convergence when dealing with planetocentric spiraling trajectories deep within a gravity well. Conversely, faster tools like SEPSPOT provide a reasonable solution but typically fail to account for other forces such as third-body gravitation, aerodynamic drag, solar radiation pressure. SEPSPOT is further constrained by its solution method, which may require a very good guess to yield a converged optimal solution. Here the authors have developed an approach using collocation intended to provide solution times comparable to those given by SEPSPOT while allowing for greater robustness and extensible force models.

  3. High Thrust-to-Power Annular Engine Technology

    Science.gov (United States)

    Patterson, Michael J.; Thomas, Robert E.; Crofton, Mark W.; Young, Jason A.; Foster, John E.

    2015-01-01

    Gridded ion engines have the highest efficiency and total impulse of any mature electric propulsion technology, and have been successfully implemented for primary propulsion in both geocentric and heliocentric environments with excellent ground/in-space correlation of performance. However, they have not been optimized to maximize thrust-to-power, an important parameter for Earth orbit transfer applications. This publication discusses technology development work intended to maximize this parameter. These activities include investigating the capabilities of a non-conventional design approach, the annular engine, which has the potential of exceeding the thrust-to-power of other EP technologies. This publication discusses the status of this work, including the fabrication and initial tests of a large-area annular engine. This work is being conducted in collaboration among NASA Glenn Research Center, The Aerospace Corporation, and the University of Michigan.

  4. Low-thrust chemical propulsion system pump technology

    Science.gov (United States)

    Meadville, J. W.

    1980-01-01

    A study was conducted within the thrust range 450 to 9000 N (100 to 2000 pounds). Performance analyses were made on centrifugal, pitot, Barske, drag, Tesla, gear, piston, lobe, and vane pumps with liquid hydrogen, liquid methane, and liquid oxygen as propellants. Gaseous methane and hydrogen driven axial impulse turbines, vane expanders, piston expanders, and electric motors were studied as drivers. Data are presented on performance, sizes, weights, and estimated service lives and costs.

  5. The Prevalence of Tongue Thrusting in Patients with Periodontal Disease

    Directory of Open Access Journals (Sweden)

    S.A. Miremadi

    2005-06-01

    Full Text Available Statement of Problem: Tongue thrust and/or its consequent swallowing pattern are amongst the parafunctional habits that have always been considered as etiological factors for dental disorders by different investigators.Purpose: The aim of this study was to investigate the prevalence of tongue thrusting and the incidence of periodontal disorders associated with this habit among patients referred to the Department of Periodontology, School of Dentistry, Tehran University of Medical Sciences.Material and Methods: Two hundred and eighty patients, undergoing first phase of periodontal therapy, were selected. Among them, those who had tongue thrusting were diagnosed and periodontal indices (probing depth, gingival recession, spacing and gingival enlargement were measured. Also, crown-root ratio was assessed for each anterior tooth.Results: Tongue thrusting was seen in 27.3%of patients, whereas 29.8% and 33.8% of them showed an increase in periodontal pocket depths in their upper and lower jaws,respectively. Gingival recession was found in the upper jaw in 12.98% and in the lowerjaw in 49.35% of the cases. Crown to root length ratio in 24.6% of the upper incisors and 35.1% of the lower incisors were found to be higher than normal. Spacing was observed between the incisors in 31.2% and 41.6% of the patients in the upper and lower jaws, respectively. Finally 31.2% of the patients showed gingival enlargement.Conclusion: The results of the present study revealed a considerable increase in the prevalence of various periodontal diseases among these subjects. To minimize the clinical problems of such patients, prevention of periodontal diseases through excellent oral hygiene and regular dental visits are suggested.

  6. Gravity as Archimedes' thrust and a bifurcation in that theory

    OpenAIRE

    Arminjon, Mayeul

    2004-01-01

    Euler's interpretation of Newton's gravity (NG) as Archimedes' thrust in a fluid ether is presented in some detail. Then a semi-heuristic mechanism for gravity, close to Euler's, is recalled and compared with the latter. None of these two "gravitational ethers" can obey classical mechanics. This is logical since the ether defines the very reference frame, in which mechanics is defined. This concept is used to build a scalar theory of gravity: NG corresponds to an incompressible ether, a compr...

  7. Jet-Engine Exhaust Nozzle With Thrust-Directing Flaps

    Science.gov (United States)

    Wing, David J.

    1996-01-01

    Convergent/divergent jet-engine exhaust nozzle has cruciform divergent passage containing flaps that move to deflect flow of exhaust in either or both planes perpendicular to main fore-and-aft axis of undeflected flow. Prototype of thrust-vector-control nozzles installed in advanced, high-performance airplanes to provide large pitching (usually, vertical) and yawing (usually, horizontal) attitude-control forces independent of attitude-control forces produced by usual aerodynamic control surfaces.

  8. CFD evaluation of an advanced thrust vector control concept

    Science.gov (United States)

    Tiarn, Weihnurng; Cavalleri, Robert

    1990-01-01

    A potential concept that can offer an alternate method for thrust vector control of the Space Shuttle Solid Rocket Booster is the use of a cylindrical probe that is inserted (on demand) through the wall of the rocket nozzle. This Probe Thrust Vector Control (PTVC) concept is an alternate to that of a gimbaled nozzle or a Liquid Injection Thrust Vector (LITVC) system. The viability of the PTVC concept can be assessed either experimentally and/or with the use of CFD. A purely experimental assessment can be time consuming and expensive, whereas a CFD assessment can be very time- and cost-effective. Two key requirements of the proposed concept are PTVC vectoring performance and the active cooling requirements for the probe to maintain its thermal and structural integrity. An active thermal cooling method is the injection of coolant around the pheriphery of the probe. How much coolant is required and how this coolant distributes itself in the flow field is of major concern. The objective of the work reported here is the use of CFD to answer these question and in the design of test hardware to substantiate the results of the CFD predictions.

  9. The NPL/ESA Micro-Newton Thrust Balance

    Science.gov (United States)

    Hughes, Ben; Perez Luna, Jaime

    2012-07-01

    Europe is pursuing a number of unique science missions which require extremely high performance micro- propulsion systems to perform precision attitude control to meet their challenging scientific goals. A number of different propulsion systems are under development to try and meet these needs, including systems based on FEEP, mini-ion and cold gas thruster technologies. The critical performance requirements for the thrusters are related to thrust accuracy, dynamic response and noise, where very challenging requirements are set. Although it is anticipated that the thruster technologies can meet these challenging requirements, verification of these performances by test presents its own difficulties, since the magnitude of the thrust noise required is close to the limit of available measurement devices, and the practicalities of testing thrusters under vacuum provide their own challenges. To address the complex measurement requirements, the UK’s National Physical Laboratory (NPL) is working closely with ESTEC to develop a state-of-the-art thrust balance that will provide traceable (to international measurement standards) measurements with a target measurement uncertainty of 1 μN (k = 2) and measurement bandwidth of 0 Hz to 10 Hz. The paper will focus on the design of the instrument, the detrimental effects of external vibration noise on the measurement, how this problem is being addressed and how we determine the measurement uncertainty in the presence of noise.

  10. Pressure drop and thrust predictions for transonic micronozzle flows

    Science.gov (United States)

    Gomez, J.; Groll, R.

    2016-02-01

    In this paper, the expansion of xenon, argon, krypton, and neon gases through a Laval nozzle is studied experimentally and numerically. The pressurized gases are accelerated through the nozzle into a vacuum chamber in an attempt to simulate the operating conditions of a cold-gas thruster for attitude control of a micro-satellite. The gases are evaluated at several mass flow rates ranging between 0.178 mg/s and 3.568 mg/s. The Re numbers are low (8-256) and the estimated values of Kn number lie between 0.33 and 0.02 (transition and slip-flow regime). Direct Simulation Monte Carlo (DSMC) and continuum-based simulations with a no-slip boundary condition are performed. The DSMC and the experimental results show good agreement in the range Kn > 0.1, while the Navier-Stokes results describe the experimental data more accurately for Kn gas-independent accommodation coefficients. The thrust delivered by the cold-gas thruster and the specific impulse is determined based on the numerical results. Furthermore, an increase of the thickness of the viscous boundary layer through the diffuser of the micronozzle is observed. This results in a shock-less decrease of the Mach number and the flow velocity, which penalizes thrust efficiency. The negative effect of the viscous boundary layer on thrust efficiency can be lowered through higher values of Re and a reduction of the diffuser length.

  11. Low Thrust, Deep Throttling, US/CIS Integrated NTRE

    Science.gov (United States)

    Culver, Donald W.; Kolganov, Vyacheslav; Rochow, Richard F.

    1994-07-01

    In 1993 our international team performed a follow-on ``Nuclear Thermal Rocket Engine (NTRE) Extended Life Feasibility Assessment'' study for the Nuclear Propulsion Office (NPO) at NASAs Lewis Research Center. The main purpose of this study was to complete the 1992 study matrix to assess NTRE designs at thrust levels of 22.5, 11.3, and 6.8 tonnes, using Commonwealth of Independent States (CIS) reactor technology. An additional Aerojet goal was to continue improving the NTRE concept we had generated. Deep throttling, mission performance optimized engine design parametrics, and reliability/cost enhancing engine system simplifications were studied, because they seem to be the last three basic design improvements sorely needed by post-NERVA NTRE. Deep throttling improves engine life by eliminating damaging thermal and mechanical shocks caused by after-cooling with pulsed coolant flow. Alternately, it improves mission performance with steady flow after-cooling by minimizing reactor over-cooling. Deep throttling also provides a practical transition from high pressures and powers of the high thrust power cycle to the low pressures and powers of our electric power generating mode. Two deep throttling designs are discussed; a workable system that was studied and a simplified system that is recommended for future study. Mission-optimized engine thrust/weight (T/W) and Isp predictions are included along with system flow schemes and concept sketches.

  12. Electric sail control mode for amplified transverse thrust

    CERN Document Server

    Toivanen, Petri; Envall, Jouni

    2014-01-01

    The electric solar wind sail produces thrust by centrifugally spanned high voltage tethers interacting with the solar wind protons. The sail attitude can be controlled and attitude maneuvers are possible by tether voltage modulation synchronous with the sail rotation. Especially, the sail can be inclined with respect to the solar wind direction to obtain transverse thrust to change the osculating orbit angular momentum. Such an inclination has to be maintained by a continual control voltage modulation. Consequently, the tether voltage available for the thrust is less than the maximum voltage provided by the power system. Using a spherical pendulum as a model for a single rotating tether, we derive analytical estimations for the control efficiency for two separate sail control modes. One is a continuous control modulation that corresponds to strictly planar tether tip motion. The other is an on-off modulation with the tether tip moving along a closed loop on a saddle surface. The novel on-off mode is introduce...

  13. Experimental evidence that thrust earthquake ruptures might open faults.

    Science.gov (United States)

    Gabuchian, Vahe; Rosakis, Ares J; Bhat, Harsha S; Madariaga, Raúl; Kanamori, Hiroo

    2017-05-18

    Many of Earth's great earthquakes occur on thrust faults. These earthquakes predominantly occur within subduction zones, such as the 2011 moment magnitude 9.0 eathquake in Tohoku-Oki, Japan, or along large collision zones, such as the 1999 moment magnitude 7.7 earthquake in Chi-Chi, Taiwan. Notably, these two earthquakes had a maximum slip that was very close to the surface. This contributed to the destructive tsunami that occurred during the Tohoku-Oki event and to the large amount of structural damage caused by the Chi-Chi event. The mechanism that results in such large slip near the surface is poorly understood as shallow parts of thrust faults are considered to be frictionally stable. Here we use earthquake rupture experiments to reveal the existence of a torquing mechanism of thrust fault ruptures near the free surface that causes them to unclamp and slip large distances. Complementary numerical modelling of the experiments confirms that the hanging-wall wedge undergoes pronounced rotation in one direction as the earthquake rupture approaches the free surface, and this torque is released as soon as the rupture breaks the free surface, resulting in the unclamping and violent 'flapping' of the hanging-wall wedge. Our results imply that the shallow extent of the seismogenic zone of a subducting interface is not fixed and can extend up to the trench during great earthquakes through a torquing mechanism.

  14. The cislunar low-thrust trajectories via the libration point

    Science.gov (United States)

    Qu, Qingyu; Xu, Ming; Peng, Kun

    2017-05-01

    The low-thrust propulsion will be one of the most important propulsion in the future due to its large specific impulse. Different from traditional low-thrust trajectories (LTTs) yielded by some optimization algorithms, the gradient-based design methodology is investigated for LTTs in this paper with the help of invariant manifolds of LL1 point and Halo orbit near the LL1 point. Their deformations under solar gravitational perturbation are also presented to design LTTs in the restricted four-body model. The perturbed manifolds of LL1 point and its Halo orbit serve as the free-flight phase to reduce the fuel consumptions as much as possible. An open-loop control law is proposed, which is used to guide the spacecraft escaping from Earth or captured by Moon. By using a two-dimensional search strategy, the ON/OFF time of the low-thrust engine in the Earth-escaping and Moon-captured phases can be obtained. The numerical implementations show that the LTTs achieved in this paper are consistent with the one adopted by the SMART-1 mission.

  15. Experimental evidence that thrust earthquake ruptures might open faults

    Science.gov (United States)

    Gabuchian, Vahe; Rosakis, Ares J.; Bhat, Harsha S.; Madariaga, Raúl; Kanamori, Hiroo

    2017-05-01

    Many of Earth’s great earthquakes occur on thrust faults. These earthquakes predominantly occur within subduction zones, such as the 2011 moment magnitude 9.0 eathquake in Tohoku-Oki, Japan, or along large collision zones, such as the 1999 moment magnitude 7.7 earthquake in Chi-Chi, Taiwan. Notably, these two earthquakes had a maximum slip that was very close to the surface. This contributed to the destructive tsunami that occurred during the Tohoku-Oki event and to the large amount of structural damage caused by the Chi-Chi event. The mechanism that results in such large slip near the surface is poorly understood as shallow parts of thrust faults are considered to be frictionally stable. Here we use earthquake rupture experiments to reveal the existence of a torquing mechanism of thrust fault ruptures near the free surface that causes them to unclamp and slip large distances. Complementary numerical modelling of the experiments confirms that the hanging-wall wedge undergoes pronounced rotation in one direction as the earthquake rupture approaches the free surface, and this torque is released as soon as the rupture breaks the free surface, resulting in the unclamping and violent ‘flapping’ of the hanging-wall wedge. Our results imply that the shallow extent of the seismogenic zone of a subducting interface is not fixed and can extend up to the trench during great earthquakes through a torquing mechanism.

  16. Performance characteristics in hydrodynamic water cooled thrust bearings

    Directory of Open Access Journals (Sweden)

    Farooq Ahmad Najar

    2016-09-01

    Full Text Available This paper deals with the study of the influence on performance characteristics of a thrust bearing with the introduction of cooling circuit and flow velocity of coolant within the designed thrust bearings is described. New method of cooling circuit configuration is taken into consideration and water has been chosen as a coolant here in the present work. Flow velocity of coolant, ranging from 0.5m/s to 2.0m/s is proposed. The Finite difference based numerical model has been developed in order to notice the effect on the heat transfer on a large hydrodynamic lubrication thrust bearing in-terms of its performance characteristics. In the present work, the solution of Reynolds equation, an energy equation with viscosity variation and Fourier heat conduction equations, applied with appropriate boundary conditions. From the present investigation, it is observed significant amount of heat content is removed from the bearing with the increase of flow velocity of coolant in an embedded cooling duct within the pad. An important parameter among performance characteristics has prevailed a significant increase in hydrodynamic pressure generation which in turn subsequently increases the load carrying capacity which has been never ever documented in the background literature.

  17. Camera Layout Design for the Upper Stage Thrust Cone

    Science.gov (United States)

    Wooten, Tevin; Fowler, Bart

    2010-01-01

    Engineers in the Integrated Design and Analysis Division (EV30) use a variety of different tools to aid in the design and analysis of the Ares I vehicle. One primary tool in use is Pro-Engineer. Pro-Engineer is a computer-aided design (CAD) software that allows designers to create computer generated structural models of vehicle structures. For the Upper State thrust cone, Pro-Engineer was used to assist in the design of a layout for two camera housings. These cameras observe the separation between the first and second stage of the Ares I vehicle. For the Ares I-X, one standard speed camera was used. The Ares I design calls for two separate housings, three cameras, and a lighting system. With previous design concepts and verification strategies in mind, a new layout for the two camera design concept was developed with members of the EV32 team. With the new design, Pro-Engineer was used to draw the layout to observe how the two camera housings fit with the thrust cone assembly. Future analysis of the camera housing design will verify the stability and clearance of the camera with other hardware present on the thrust cone.

  18. Research on Instantaneous Thrust Measurement for Attitude-control Solid Rocket Motor

    Institute of Scientific and Technical Information of China (English)

    OUYANG Hua-bing; WANG Jian-ping; LIN Feng; XU Wen-gan

    2008-01-01

    In order to measure the instantaneous thrust of a certain attitude-control solid rocket motor, based on the analysis of the measurement principles, the difference between the instantaneous thrust and steady thrust measurements is pointed out. According to the measurement characteristics, a dynamic digital filter compensation method is presented. Combined the identification-modeling, dynamic compensation and simulation, the system's dynamic mathematic model is established. And then, a compensation digital filter is also designed. Thus, the dynamic response of the system is improved and the instantaneous thrust measurement can be implemented. The measurement results for the rocket motor show that the digital filter compensation is effective in the instantaneous thrust measurement.

  19. Evaluation of thrusting and folding of the Deadman Creek Thrust Fault, Sangre de Cristo range, Saguache County, Colorado

    Science.gov (United States)

    Weigel, Jacob F., II

    The Deadman Creek Thrust Fault was mapped in a structural window on the west side of the Sangre de Cristo Range. The study area, located in southern Colorado, is a two square mile area halfway between the town of Crestone and the Great Sand Dunes National Park. The Deadman Creek Thrust Fault is the center of this study because it delineates the fold structure in the structural window. The fault is a northeast-directed low-angle thrust folded by subsequent additional compression. This study was directed at understanding the motion of the Deadman Creek Thrust Fault as affected by subsequent folding, and the driving mechanism behind the folding of the Pole Creek Anticline as part of a broader study of Laramide thrust faulting in the range. This study aids in the interpretation of the geologic structure of the San Luis Valley, which is being studied by staff of the United States Geological Survey (USGS), to understand Rio Grande Rift basin evolution by focusing on rift and pre-rift tectonic activity. It also provides a geologic interpretation for the Saguache County Forest Service, Great Sand Dunes National Park, and its visitors. The Sangre de Cristo Mountain Range has undergone tectonic events in the Proterozoic, Pennsylvanian (Ancestral Rocky Mountains), Cretaceous-Tertiary (Laramide Orogeny) and mid-Tertiary (Rio Grande Rift). During the Laramide Orogeny the Deadman Creek Thrust Fault emplaced Proterozoic gneiss over Paleozoic sedimentary rocks and Proterozoic granodiorite in the area. Continued deformation resulted in folding of the fault to form the Pole Creek Anticline. The direction of motion of both the fault and fold is northeastward. A self-consistent net of cross-sections and stereonet plots generated from existing and new field data show that the anticline is an overturned isoclinal fold in Pole Creek Canyon, which shows an increasing inter-limb angle and a more vertical axial surface northwestward toward Deadman Creek Canyon. Southwest-directed apparent

  20. Attitude Control for an Aero-Vehicle Using Vector Thrusting and Variable Speed Control Moment Gyros

    Science.gov (United States)

    Shin, Jong-Yeob; Lim, K. B.; Moerder, D. D.

    2005-01-01

    Stabilization of passively unstable thrust-levitated vehicles can require significant control inputs. Although thrust vectoring is a straightforward choice for realizing these inputs, this may lead to difficulties discussed in the paper. This paper examines supplementing thrust vectoring with Variable-Speed Control Moment Gyroscopes (VSCMGs). The paper describes how to allocate VSCMGs and the vectored thrust mechanism for attitude stabilization in frequency domain and also shows trade-off between vectored thrust and VSCMGs. Using an H2 control synthesis methodology in LMI optimization, a feedback control law is designed for a thrust-levitated research vehicle and is simulated with the full nonlinear model. It is demonstrated that VSCMGs can reduce the use of vectored thrust variation for stabilizing the hovering platform in the presence of strong wind gusts.

  1. Advanced Active-Magnetic-Bearing Thrust-Measurement System

    Science.gov (United States)

    Imlach, Joseph; Kasarda, Mary; Blumber, Eric

    2008-01-01

    An advanced thrust-measurement system utilizes active magnetic bearings to both (1) levitate a floating frame in all six degrees of freedom and (2) measure the levitation forces between the floating frame and a grounded frame. This system was developed for original use in measuring the thrust exerted by a rocket engine mounted on the floating frame, but can just as well be used in other force-measurement applications. This system offers several advantages over prior thrust-measurement systems based on mechanical support by flexures and/or load cells: The system includes multiple active magnetic bearings for each degree of freedom, so that by selective use of one, some, or all of these bearings, it is possible to test a given article over a wide force range in the same fixture, eliminating the need to transfer the article to different test fixtures to obtain the benefit of full-scale accuracy of different force-measurement devices for different force ranges. Like other active magnetic bearings, the active magnetic bearings of this system include closed-loop control subsystems, through which the stiffness and damping characteristics of the magnetic bearings can be modified electronically. The design of the system minimizes or eliminates cross-axis force-measurement errors. The active magnetic bearings are configured to provide support against movement along all three orthogonal Cartesian axes, and such that the support along a given axis does not produce force along any other axis. Moreover, by eliminating the need for such mechanical connections as flexures used in prior thrust-measurement systems, magnetic levitation of the floating frame eliminates what would otherwise be major sources of cross-axis forces and the associated measurement errors. Overall, relative to prior mechanical-support thrust-measurement systems, this system offers greater versatility for adaptation to a variety of test conditions and requirements. The basic idea of most prior active

  2. Near Earth Asteroid Scout Solar Sail Thrust and Torque Model

    Science.gov (United States)

    Heaton, Andy; Ahmad, Naeem; Miller, Kyle

    2017-01-01

    The Near Earth Asteroid (NEA) Scout is a solar sail mission whose objective is to scout at least one Near Earth Asteroid to help prepare for human missions to Near Earth Asteroids. NEA Scout will launch as a secondary payload on the first SLS-Orion mission. NEA Scout will perform a small trim maneuver shortly after deploy from the spent SLS upper stage using a cold gas propulsion system, but from that point on will depend entirely on the solar sail for thrust. As such, it is important to accurately characterize the thrust of the sail in order to achieve mission success. Additionally, the solar sail creates a relatively large solar disturbance torque that must be mitigated. For early mission design studies a flat plate model of the solar sail with a fixed center of pressure was adequate, but as mission concepts and the sail design matured, greater fidelity was required. Here we discuss the progress to a three-dimensional sail model that includes the effects of tension and thermal deformation that has been derived from a large structural Finite Element Model (FEM) developed by the Langley Research Center. We have found that the deformed sail membrane affects torque relatively much more than thrust; a flat plate model could potentially model thrust well enough to close mission design studies, but a three-dimensional solar sail is essential to control system design. The three-dimensional solar sail model revealed that thermal deformations of unshielded booms would create unacceptably large solar disturbance torques. The original large FEM model was used in control and mission simulations, but was resulted in simulations with prohibitive run times. This led us to adapt the Generalized Sail Model (GSM) of Rios-Reyes. A design reference sail model has been baselined for NEA Scout and has been used to design the mission and control system for the sailcraft. Additionally, since NEA Scout uses reaction wheels for attitude pointing and control, the solar torque model is

  3. Thermal barrier coatings (TBC's) for high heat flux thrust chambers

    Science.gov (United States)

    Bradley, Christopher M.

    The last 30 years materials engineers have been under continual pressure to develop materials with a greater temperature potential or to produce configurations that can be effectively cooled or otherwise protected at elevated temperature conditions. Turbines and thrust chambers produce some of the harshest service conditions for materials which lead to the challenges engineers face in order to increase the efficiencies of current technologies due to the energy crisis that the world is facing. The key tasks for the future of gas turbines are to increase overall efficiencies to meet energy demands of a growing world population and reduce the harmful emissions to protect the environment. Airfoils or blades tend to be the limiting factor when it comes to the performance of the turbine because of their complex design making them difficult to cool as well as limitations of their thermal properties. Key tasks for space transportation it to lower costs while increasing operational efficiency and reliability of our space launchers. The important factor to take into consideration is the rocket nozzle design. The design of the rocket nozzle or thrust chamber has to take into account many constraints including external loads, heat transfer, transients, and the fluid dynamics of expanded hot gases. Turbine engines can have increased efficiencies if the inlet temperature for combustion is higher, increased compressor capacity and lighter weight materials. In order to push for higher temperatures, engineers need to come up with a way to compensate for increased temperatures because material systems that are being used are either at or near their useful properties limit. Before thermal barrier coatings were applied to hot-section components, material alloy systems were able to withstand the service conditions necessary. But, with the increased demand for performance, higher temperatures and pressures have become too much for those alloy systems. Controlled chemistry of hot

  4. Reliability and validity of a tool to measure the severity of tongue thrust in children: the Tongue Thrust Rating Scale.

    Science.gov (United States)

    Serel Arslan, S; Demir, N; Karaduman, A A

    2017-02-01

    This study aimed to develop a scale called Tongue Thrust Rating Scale (TTRS), which categorised tongue thrust in children in terms of its severity during swallowing, and to investigate its validity and reliability. The study describes the developmental phase of the TTRS and presented its content and criterion-based validity and interobserver and intra-observer reliability. For content validation, seven experts assessed the steps in the scale over two Delphi rounds. Two physical therapists evaluated videos of 50 children with cerebral palsy (mean age, 57·9 ± 16·8 months), using the TTRS to test criterion-based validity, interobserver and intra-observer reliability. The Karaduman Chewing Performance Scale (KCPS) and Drooling Severity and Frequency Scale (DSFS) were used for criterion-based validity. All the TTRS steps were deemed necessary. The content validity index was 0·857. A very strong positive correlation was found between two examinations by one physical therapist, which indicated intra-observer reliability (r = 0·938, P thrust in children. © 2016 John Wiley & Sons Ltd.

  5. Why do airlines want and use thrust reversers? A compilation of airline industry responses to a survey regarding the use of thrust reversers on commercial transport airplanes

    Science.gov (United States)

    Yetter, Jeffrey A.

    1995-01-01

    Although thrust reversers are used for only a fraction of the airplane operating time, their impact on nacelle design, weight, airplane cruise performance, and overall airplane operating and maintenance expenses is significant. Why then do the airlines want and use thrust reversers? In an effort to understand the airlines need for thrust reversers, a survey of the airline industry was made to determine why and under what situations thrust reversers are currently used or thought to be needed. The survey was intended to help establish the cost/benefits trades for the use of thrust reversers and airline opinion regarding alternative deceleration devices. A compilation and summary of the responses given to the survey questionnaire is presented.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-11-10

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

  7. Quantifying varus and valgus thrust in individuals with severe knee osteoarthritis.

    Science.gov (United States)

    Sosdian, L; Hinman, R S; Wrigley, T V; Paterson, K L; Dowsey, M; Choong, P; Bennell, K

    2016-11-01

    Varus-valgus thrust is a biomechanical characteristic linked to knee osteoarthritis disease progression. This study aimed to determine: i) direction of thrust in individuals awaiting total knee arthroplasty versus controls, ii) whether thrust and related parameters differed between groups, iii) differences between osteoarthritis patients awaiting surgery with varus and valgus thrust. 44 patients scheduled for surgery and 40 asymptomatic participants were recruited. varus-valgus thrust excursion and absolute thrust magnitude, quantified by 3D gait analysis. Few differences were found between the osteoarthritis group and controls. The osteoarthritis group as a whole had a more varus knee angle during early- (pthrust osteoarthritis subgroup had a more varus knee angle in overall (p=0.012), early- (pthrust controls. No differences were found between the valgus thrust osteoarthritis and control groups. The varus thrust osteoarthritis group had a greater varus peak knee angle in overall (pthrust osteoarthritis group. Those with severe osteoarthritis and a varus thrust have poorer biomechanics, more varus static knee alignment, and lower quadriceps strength compared to those with osteoarthritis with a valgus thrust. Further work is needed to determine if these findings impact total knee arthroplasty outcome. Copyright © 2016. Published by Elsevier Ltd.

  8. Emergency Flight Control Using Computer-Controlled Thrust

    Science.gov (United States)

    Burcham, Frank W., Jr.; Fullerton, C. Gordon; Stewart, James F.; Gilyard, Glenn B.; Conley, Joseph A.

    1995-01-01

    Propulsion Controlled Aircraft (PCA) systems are digital electronic control systems undergoing development to provide limited maneuvering ability through variations of individual engine thrusts in multiple-engine airplanes. Provide landing capability when control surfaces inoperable. Incorporated on existing and future airplanes that include digital engine controls, digital flight controls, and digital data buses, adding no weight for additional hardware to airplane. Possible to handle total failure of hydraulic system, depending on how surfaces respond to loss of hydraulic pressure, and broken control cables or linkages. Future airplanes incorporate data from Global Positioning System for guidance to any suitable emergency runway in world.

  9. Earth tides can trigger shallow thrust fault earthquakes.

    Science.gov (United States)

    Cochran, Elizabeth S; Vidale, John E; Tanaka, Sachiko

    2004-11-12

    We show a correlation between the occurrence of shallow thrust earthquakes and the occurrence of the strongest tides. The rate of earthquakes varies from the background rate by a factor of 3 with the tidal stress. The highest correlation is found when we assume a coefficient of friction of mu = 0.4 for the crust, although we see good correlation for mu between 0.2 and 0.6. Our results quantify the effect of applied stress on earthquake triggering, a key factor in understanding earthquake nucleation and cascades whereby one earthquake triggers others.

  10. Passive Thrust Oscillation Mitigation for the CEV Crew Pallet System

    Science.gov (United States)

    Sammons, Matthew; Powell, Cory; Pellicciotti, Joseph; Buehrle, Ralph; Johnson, Keith

    2012-01-01

    The Crew Exploration Vehicle (CEV) was intended to be the next-generation human spacecraft for the Constellation Program. The CEV Isolator Strut mechanism was designed to mitigate loads imparted to the CEV crew caused by the Thrust Oscillation (TO) phenomenon of the proposed Ares I Launch Vehicle (LV). The Isolator Strut was also designed to be compatible with Launch Abort (LA) contingencies and landing scenarios. Prototype struts were designed, built, and tested in component, sub-system, and system-level testing. The design of the strut, the results of the tests, and the conclusions and lessons learned from the program will be explored in this paper.

  11. Privaatne ja avalik nõukogude aja mõistmises ühe keskastme juhi eluloo näitel. Private and Public in the Soviet Era: The Example of a Mid-Level Manager’s Life Story

    Directory of Open Access Journals (Sweden)

    Ene Kõresaar

    2012-04-01

    Full Text Available The focus of our analysis is the question of how the complex world of Soviet everyday life – which was characterised by a tension between public and private – has manifested itself in the recounting of life stories. In the article we first take a look at the problem of public and private, and the possibilities of using this theoretical model when researching everyday life in the Soviet Union. In approaching the subject, we support ourselves with the approaches of Garcelon, Voronkov and Zdravomyslova. Garcelon has, in research on Soviet society, distinguished the official and private spheres as opposites, and an area between these two spheres which encompasses features of both; Garcelon calls this the social sphere of working life. Zdravomyslova and Voronkov distinguish a third sphere: an in-between, an informal official part of life in which, in their view, Soviet society never gained total control of the individual. In both approaches, a situation arose in the Soviet society of the 1960s where informal rules began to dominate over official ones, thereby enabling a flexible kind of manipulation. In the article, we analyse the relationship between official, informal and private in the sphere of work using an oral history perspective. Here, we used Alessandro Portelli’s tripartite mode of history-telling. Portelli treats lifestory narrative as a structurally complex text where changes in usage of language and definitions of time denote general changes in experience. The characters, space and grammar change depending on the perspective used in narration. Proceeding from this, Portelli distinguishes an institutional, societal and personal level in the narration of history. The life story analysed was written by a mid-level industrial manager and sent to the life writing campaign ’My Life and the Life of My Family in Soviet Estonia and in the Republic of Estonia’ in 2001. A characteristic feature of the industrial manager’s work biography

  12. Some three-body numerical solutions for low-thrust orbiter missions.

    Science.gov (United States)

    Mackay, J. S.; Mascy, A. C.

    1971-01-01

    A ?velocity at the sphere of influence' method and an asymptotic matching method of patching together two-body low thrust solutions are compared to a number of three-body numerical results for outer planet orbiter missions. The two patching methods compare well with the numerical three-body results and do not depend on any particular choice for the size of the sphere of influence. The results apply, in a strict sense, only to the operational mode used-high-thrust terminal retro into orbit. Low-thrust spirals are not considered in the three-body analysis. The terminal low-thrust phase of thrusting is almost entirely reverse to the velocity vector during the planet centered phase of the trajectory. This may lead to important simplifications for low-thrust guidance and navigation procedures.

  13. Thrust-breakthrough of asymmetric anticlines: Observational constraints from surveys in the Brooks Range, Alaska

    Science.gov (United States)

    Jadamec, Margarete A.; Wallace, Wesley K.

    2014-05-01

    To gain insights into the processes governing the thrust-truncation of anticlines, we conducted a field study of the thrust-truncated folds in the remote Brooks Range of northern Alaska, where there is a transition in fold style from symmetric detachment folds to thrust-truncated asymmetric folds. In order to document the detailed geometry of the km-scale folds exposed in cliff-forming, largely inaccessible outcrops, a new surveying technique was developed that combines data from a theodolite and laser range finder. The field observations, survey profiles, and cross section reconstructions, indicate that late-stage thrust breakthrough of the anticlines within the mechanically competent Lisburne Group carbonates accommodated continued shortening when other mechanisms became unfeasible, including fold tightening, forelimb rotation, and parasitic folding in the anticline forelimbs. These results provide constraints on the processes that govern the transition from buckle folding to thrust truncation in fold-and-thrust belts worldwide.

  14. Three-dimensional geometry of thrust surfaces and the origin of sinuous thrust traces in orogenic belts: Insights from scaled sandbox experiments

    Science.gov (United States)

    Chattopadhyay, A.; Jain, M.; Bhattacharjee, D.

    2014-12-01

    Sinuous traces of emerging thrust tips, comprising multiple salients and recesses, are commonly observed in orogenic belts (e.g. Lesser Himalayas of India, Nepal and Bhutan) and in accretionary prisms (e.g. Nankai Trough off the coast of Japan). Lateral (along the strike of the deformation zone) variation in the depths of foreland basins (i.e. variable sediment thickness) or in the strength of the basal detachment, or presence of a curved indenter has been traditionally cited to explain the formation of salients in fold-and-thrust belts, although they are not applicable in all cases. In the present work, we have carried out four series of scaled analog model experiments using dry quartz sand, changing the dip of the basal decollément (β = 0° or 5°) and the basal friction (μb = 0.5 or 0.3) to investigate the 3D shape of thrust surfaces under varying overall boundary conditions, but without any lateral variation of these parameters, within the models. The experimental results show that under all boundary conditions, thrust surfaces are curved both in their dip and strike directions (i.e. spoon-shaped in 3D). Multiple concave-upward and convex-upward segments constitute a thrust surface, which produces a sinuous trace when the tip line intersects the Earth's surface. It is also shown that thrust surface curvatures occur at different scales, and the overall thrust surface roughness (corrugations) has a self-affine fractal geometry.

  15. Thrust producing mechanisms in ray-inspired underwater vehicle propulsion

    Directory of Open Access Journals (Sweden)

    Geng Liu

    2015-01-01

    Full Text Available This paper describes a computational study of the hydrodynamics of a ray-inspired underwater vehicle conducted concurrently with experimental measurements. High-resolution stereo-videos of the vehicle’s fin motions during steady swimming are obtained and used as a foundation for developing a high fidelity geometrical model of the oscillatory fin. A Cartesian grid based immersed boundary solver is used to examine the flow fields produced due to these complex artificial pectoral fin kinematics. Simulations are carried out at a smaller Reynolds number in order to examine the hydrodynamic performance and understand the resultant wake topology. Results show that the vehicle’s fins experience large spanwise inflexion of the distal part as well as moderate chordwise pitching during the oscillatory motion. Most thrust force is generated by the distal part of the fin, and it is highly correlated with the spanwise inflexion. Two sets of inter-connected vortex rings are observed in the wake right behind each fin. Those vortex rings induce strong backward flow jets which are mainly responsible for the fin thrust generation.

  16. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    Science.gov (United States)

    Scarritt, Sara K.; Marchand, Belinda G.; Brown, Aaron J.; Tracy, William H.; Weeks, Michael W.

    2010-01-01

    In earlier investigations, the adaptation and implementation of a modified two-level corrections (or targeting) process as the onboard targeting algorithm for the Trans-Earth Injection phase of Orion is presented. The objective of that targeting algorithm is to generate the times of ignition and magnitudes of the required maneuvers such that the desired state at entry interface is achieved. In an actual onboard flight software implementation, these times of ignition and maneuvers are relayed onto Flight Control for command and execution. Although this process works well when the burn durations or burn arcs are small, this might not be the case during a contingency situation when lower thrust engines are employed to perform the maneuvers. Therefore, a new model for the two-level corrections process is formulated here to accommodate finite burn arcs. This paper presents the development and formulation of the finite burn two-level corrector, used as an onboard targeting algorithm for the Trans-Earth Injection phase of Orion. A performance comparison between the impulsive and finite burn models is also presented. The present formulation ensures all entry constraints are met, without violating the available fuel budget, while allowing for low-thrust scenarios with long burn durations.

  17. Shock unsteadiness in a thrust optimized parabolic nozzle

    Science.gov (United States)

    Verma, S. B.

    2009-07-01

    This paper discusses the nature of shock unsteadiness, in an overexpanded thrust optimized parabolic nozzle, prevalent in various flow separation modes experienced during start up {(δ P0 /δ t > 0)} and shut down {(δ P0/δ t tube. Shock unsteadiness in the separation region is seen to increase significantly just before the onset of each flow transition, even during steady nozzle operation. The intensity of this measure ( rms level) is seen to be strongly influenced by relative locations of normal and overexpansion shock, the decrease in radial size of re-circulation zone in the back-flow region, and finally, the local nozzle wall contour. During restricted shock separation, the pressure fluctuations in separation region exhibit periodic characteristics rather than the usually observed characteristics of intermittent separation. The possible physical mechanisms responsible for the generation of flow unsteadiness in various separation modes are discussed. The results are from an experimental study conducted in P6.2 cold-gas subscale test facility using a thrust optimized parabolic nozzle of area-ratio 30.

  18. Resin Transfer Moulding Of An Engine Thrust Frame Cone Cap

    Science.gov (United States)

    Brodsjo, Anders; Fatemi, Javad; de Vries, Henri

    2012-07-01

    For the Ariane 5 Midlife Evolution, a new Engine Thrust Frame for the upper stage is being developed. Part of this Engine Thrust Frame is the so-called Cone Cap, which closes the inverted cone shape of the structure. This part is highly loaded, as it transfers all the loads from the engines to the cone shape, and includes the hinge points for the mechanism that steer the engines. Besides strength to cope with the loads, stiffness is a very important design parameter. A composite design of this structure has been developed, which is approximately 15 kg’s lighter than the aluminium structure. To manufacture such a part in composites is challenging, because of the complexity of the shape and large laminate thickness. Due to these requirements, Resin Transfer Moulding has been selected as manufacturing method, which allows this highly integrated structure to be made in one step. As part of this project, a quarter segment of the full-scale design has been manufactured. From the design model, a detailed design for the dry fibre preform has been made using advanced composite laminate software tools. This preform was placed inside a heated, double sided tool and injected with the resin.

  19. Near Earth Asteroid Scout Thrust and Torque Model

    Science.gov (United States)

    Heaton, Andrew; Ahmad, Naeem; Miller, Kyle

    2017-01-01

    The Near Earth Asteroid (NEA) Scout is a solar sail mission whose objective is to scout at least one Near Earth Asteroid in preparation for manned missions to asteroids. NEA Scout will use a solar sail as the primary means of propulsion. Thus it is important for mission planning to accurately characterize the thrust of the sail. Additionally, the solar sail creates a relatively large solar disturbance torque that must be mitigated. For early mission design studies a flat plate model of the solar sail with a fixed center of pressure was adequate, but as mission concepts and the sail design matured, greater fidelity was required. Here we discuss the progress to a three-dimensional sail model that includes the effects of tension and thermal deformation that has been derived from a large structural Finite Element Model (FEM) developed by the Langley Research Center. We have found that the deformed sail membrane affects torque relatively much more than thrust. We have also found that other than uncertainty over the precise shape, the effect of small (approximately millimeter scale) wrinkles on the diffusivity of the sail is the leading remaining source of uncertainty. We demonstrate that millimeter-scale wrinkles can be modeled analytically as a change in the fraction of specular reflection. Finally we discuss the implications of these results for the NEA Scout mission.

  20. A review of definitions of the Himalayan Main Central Thrust

    Science.gov (United States)

    Martin, Aaron J.

    2017-09-01

    Most workers regard the Main Central Thrust (MCT) as one of the key high strain zones in the Himalaya because it accommodated at least 90 km of shortening, because that shortening exhumed and buried hanging wall and footwall rocks, and due to geometric and kinematic connections between the Main Central Thrust and the structurally overlying South Tibet Detachment. Geologists currently employ three unrelated definitions of the MCT: metamorphic-rheological, age of motion-structural, or protolith boundary-structural. These disparate definitions generate map and cross-section MCT positions that vary by up to 5 km of structural distance. The lack of consensus and consequent shifting locations impede advances in our understanding of the tectonic development of the orogen. Here, I review pros and cons of the three MCT definitions in current use. None of these definitions is flawless. The metamorphic-rheological and age of motion-structural definitions routinely fail throughout the orogen, whereas the protolith boundary-structural definition may fail only in rare cases, all limited to sectors of the eastern Himalaya. Accordingly, a definition based on high strain zone geometry and kinematics combined with identification of a protolith boundary is the best working definition of the MCT.

  1. Research at IMU: achievements, thrust areas and future challenges

    Directory of Open Access Journals (Sweden)

    Wan-Loy Chu

    2013-04-01

    Full Text Available There have been significant achievements inresearch at IMU as indicated by the increasing amountof external funds obtained, and number of publicationsand postgraduate students produced since it startedits research activities in the year 2000. However, it isa great challenge indeed to ensure sustainability ofour research, which is currently heavily dependent oninternal funding. There is a need to realign our strategiesto further enhance our competitiveness in securingexternal funding for research. In line with this, theInstitute for Research, Development and Innovation(IRDI was officially established on 18 September2012. The Institute will serve as a platform to supportall research activities at IMU. There are four Centresof Excellence based on the identified thrust areas underIRDI, namely 1 Centre for Bioactive Molecules andDrug Discovery; 2 Centre for Environmental andPopulation Health; 3 Centre for Cancer and StemCell Research, and 4 Centre for Health ProfessionalEducation Research. Major findings based on research inthese four thrust areas are reviewed in this paper. Withthe strategic planning and establishment of IRDI, it isour aspiration to bring research at IMU to a higher level.

  2. A review of definitions of the Himalayan Main Central Thrust

    Science.gov (United States)

    Martin, Aaron J.

    2016-11-01

    Most workers regard the Main Central Thrust (MCT) as one of the key high strain zones in the Himalaya because it accommodated at least 90 km of shortening, because that shortening exhumed and buried hanging wall and footwall rocks, and due to geometric and kinematic connections between the Main Central Thrust and the structurally overlying South Tibet Detachment. Geologists currently employ three unrelated definitions of the MCT: metamorphic-rheological, age of motion-structural, or protolith boundary-structural. These disparate definitions generate map and cross-section MCT positions that vary by up to 5 km of structural distance. The lack of consensus and consequent shifting locations impede advances in our understanding of the tectonic development of the orogen. Here, I review pros and cons of the three MCT definitions in current use. None of these definitions is flawless. The metamorphic-rheological and age of motion-structural definitions routinely fail throughout the orogen, whereas the protolith boundary-structural definition may fail only in rare cases, all limited to sectors of the eastern Himalaya. Accordingly, a definition based on high strain zone geometry and kinematics combined with identification of a protolith boundary is the best working definition of the MCT.

  3. Analytical Equations for Orbital Transfer Maneuvers of a Vehicle Using Constant Low Thrust

    Science.gov (United States)

    1981-12-01

    136auks" ,b , .. .. a. AFIT/GA/AA/81D -3 ANALITICAL EQUATIOIS FOR OR.BITAL TRASFER MANIUVRS OF A V 1CI, USING CONSTANT LOW THRUST THESIS AFIT/GA/AA...conventional chemical propulsion system- (Ref 1). Changing the velocity of a satellite such as described above can be used to boost a satellite into...taneously. This is a valid assumption for high thrust chemical propulsion, but not for low thrust electric propulsion. Therefore, a set of equations

  4. Understanding Spacecraft Agility for Orbit Transfers on the Dawn Low-thrust Mission

    Science.gov (United States)

    Smith, Brett A.; Vanelli, C. Anthony; Lee, Allan Y.

    2012-01-01

    Conventional maneuver design processes were inadequate. Long thrusting durations with the small force of SEP. Increased coupling between ACS and NAV teams. Definition of quantifiable constraints proved impractical. Specifically for the Dawn mission, because of the attitude steering algorithm. A time-efficient simulation tool, qSTAT, was developed and allowed fast verification of candidate thrust profile designs. This approach allowed Dawn to overcome the complications of low-thrust orbit transfers.

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

    Science.gov (United States)

    Kharytonov, Oleksii M.; Kiforenko, Boris M.

    2011-08-01

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

  6. Seafloor expression and shallow structure of a fold-and-thrust system, Isfjorden, west Spitsbergen

    Directory of Open Access Journals (Sweden)

    Maria Blinova

    2012-09-01

    Full Text Available A detailed map of the structure of the west Spitsbergen fold-and-thrust belt in the Isfjorden area, Spitsbergen, is presented. The map was constructed from a dense grid of two-dimensional multichannel reflection seismic and bathymetric data. Joint interpretation of two data sets allowed a comparison of tectonic structures detected along the uppermost parts of the seismic sections and those reflected in the morphology of the seafloor. Three major, predominantly north-west–south-east striking faults were identified. The westernmost fault (T1 is a hinterland-directed (most likely out of sequence thrust, while the central and easternmost faults (T2 and T3 are foreland-directed (in-sequence thrusts. The thrusts divide Isfjorden into three subareas. Subarea 1 is bounded by thrust faults T1 and T2 and comprises Tertiary rocks surrounded by Jurassic–Cretaceous strata. The structural signature of Subarea 1 is that of a system of hinterland- and foreland-directed thrust faults, resulting in a seafloor relief characterized by parallel ridges and troughs. Subarea 2 is limited by thrust faults T2 and T3 and shows Jurassic–Cretaceous outcrops on the seafloor. Subarea 3 is situated east of the main thrust fault T3 and mainly involves outcrops of Triassic–Jurassic rocks. Together, Subareas 2 and 3 are dominated by foreland-directed, north-west–south-east and NNW–SSE-striking thrusts that are hardly detectable in bathymetric data.

  7. A cislunar guidance methodology and model for low thrust trajectory generation

    Science.gov (United States)

    Korsmeyer, David J.

    1992-01-01

    A guidance methodology for generating low-thrust cislunar trajectories was developed and incorporated in a computer model. The guidance methodology divides the cislunar transfer into three phases. Each phase is discussed in turn. To establish the effectiveness of the methodology and algorithms the computer model generated three example cases for the cislunar transfer of a low-thrust electric orbital transfer vehicle (EOTV). Transfers from both earth orbit to lunar orbit and from lunar orbit back to earth orbit are considered. The model allows the determination of the low-thrust EOTV's time-of-flight, propellant mass, payload mass, and thrusting history.

  8. Experimental study of a low-thrust measurement system for thruster ground tests.

    Science.gov (United States)

    Gong, Jingsong; Hou, Lingyun; Zhao, Wenhua

    2014-03-01

    The development of thrusters used for the control of position and orbit of micro-satellites requires thrust stands that can measure low thrust. A new method to measure low thrust is presented, and the measuring device is described. The test results show that the thrust range is up to 1000 mN, the measurement error of the device is lower than ±1% of full scale, and the drift of the zero offset is less than ±1% of full scale. Its response rise time is less than 15 ms. It is employed to measure the working process of a model chemical thruster with repeatability.

  9. Paleoseismic investigations at the Cal thrust fault, Mendoza, Argentina

    Science.gov (United States)

    Salomon, Eric; Schmidt, Silke; Hetzel, Ralf; Mingorance, Francisco

    2010-05-01

    Along the active mountain front of the Andean Precordillera between 30°S and 34°S in western Argentina several earthquakes occurred in recent times, including a 7.0 Ms event in 1861 which destroyed the city of Mendoza and killed two thirds of its population. The 1861 event and two other earthquakes (Ms = 5.7 in 1929 and Ms = 5.6 in 1967) were generated on the Cal thrust fault, which extends over a distance of 31 km north-south and runs straight through the center of Mendoza. In the city, which has now more than 1 million inhabitants, the fault forms a 3-m-high fault scarp. Although the Cal thrust fault poses a serious seismic hazard, the paleoseismologic history of this fault and its long-term slip rate remains largely unknown (Mingorance, 2006). We present the first results of an ongoing paleoseismologic study of the Cal thrust at a site located 5 km north of Mendoza. Here, the fault offsets Late Holocene alluvial fan sediments by 2.5 m vertically and exhibits a well developed fault scarp. A 15-m-long and 2-3-m-deep trench across the scarp reveals three east-vergent folds that we interpret to have formed during three earthquakes. Successive retrodeformation of the two youngest folds suggests that the most recent event (presumably the 1861 earthquake) caused ~1.1 m of vertical offset and ~1.8 m of horizontal shortening. For the penultimate event we obtain a vertical offset of ~0.7 m and a horizontal shortening of ~1.9 m. A vertical displacement of ~0.7 m observed on a steeply west-dipping fault may be associated with an older event. The cumulative vertical offset of 2.5 m for the three inferred events is in excellent agreement with the height of the scarp. Based on the retrodeformation of the trench deposits the fault plane dips ~25° to the west. In the deepest part of the trench evidence for even older seismic events is preserved beneath an angular unconformity that was formed during a period of erosion and pre-dates the present-day scarp. Dating of samples to

  10. Quantifying the high-velocity, low-amplitude spinal manipulative thrust: a systematic review.

    Science.gov (United States)

    Downie, Aron S; Vemulpad, Subramanyam; Bull, Peter W

    2010-09-01

    The purpose of this study was to systematically review studies that quantify the high-velocity, low-amplitude (HVLA) spinal thrust, to qualitatively compare the apparatus used and the force-time profiles generated, and to critically appraise studies involving the quantification of thrust as an augmented feedback tool in psychomotor learning. A search of the literature was conducted to identify the sources that reported quantification of the HVLA spinal thrust. MEDLINE-OVID (1966-present), MANTIS-OVID (1950-present), and CINAHL-EBSCO host (1981-present) were searched. Eligibility criteria included that thrust subjects were human, animal, or manikin and that the thrust type was a hand-delivered HVLA spinal thrust. Data recorded were single force, force-time, or displacement-time histories. Publications were in English language and after 1980. The relatively small number of studies, combined with the diversity of method and data interpretation, did not enable meta-analysis. Twenty-seven studies met eligibility criteria: 17 studies measured thrust as a primary outcome (13 human, 2 cadaver, and 2 porcine). Ten studies demonstrated changes in psychomotor learning related to quantified thrust data on human, manikin, or other device. Quantifiable parameters of the HVLA spinal thrust exist and have been described. There remain a number of variables in recording that prevent a standardized kinematic description of HVLA spinal manipulative therapy. Despite differences in data between studies, a relationship between preload, peak force, and thrust duration was evident. Psychomotor learning outcomes were enhanced by the application of thrust data as an augmented feedback tool. Copyright © 2010 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  11. Jaw-thrust induces sympathetic responses during induction of general anesthesia.

    Science.gov (United States)

    Park, Sang-Jin; Kim, Bum Soo; Jee, Dae-Lim

    2013-08-01

    Jaw-thrust is a noxious stimulus that might induce sympathetic responses. The purpose of this study, was to evaluate the effects of jaw-thrust on sympathetic responses. We investigated seventy three patients. Patients who received general anesthesia were randomly divided into a control group (maintenance of combined airway maneuver with head tilt, open mouth by mouthpiece, and chin-lift, n = 30) and jaw-thrust group (maintenance of head tilt, open mouth and jaw-thrust, n = 30). In the jaw-thrust group, four minutes of endoscopy-guided force to the mandible to get the best laryngeal view were applied. For the control group, the combined airway maneuver was maintained during the same period. Arterial blood pressure (AP) and heart rate (HR) were recorded at predetermined time points (1 min before anesthesia induction, 2 min after fiberoptic bronchoscopy placement, and thereafter 1 min-interval during each airway maneuver) during jaw-thrust and chin-lift maneuver. The force amplitude applied for best laryngeal view during jaw-thrust was also measured. Peak systolic and diastolic AP increased 39.0 ± 17.6 and 39.9 ± 22.8 mmHg from the baseline (P thrust group. HR was also 32.5 ± 19.4 beats/min from the baseline (P thrust group. These remained high at all time points, compared with the control group (P thrust was not correlated to the AP and HR changes (P > 0.05). Performing the jaw-thrust maneuver induces significant sympathetic responses, irrespective of the force magnitude.

  12. Tectonics of the Himalayan thrust belt in northern Pakistan

    Science.gov (United States)

    Yeats, R. S.; Lawrence, R. D.

    1982-01-01

    It is pointed out that the Himalayan ranges of southern Asia represent a dilemma in modern plate tectonic theory. Alvarez (1982) has tried to resolve some of the problems, but inconsistencies remain. The present investigation considers some of the problems which are now encountered in light of present knowledge. The investigation is concerned mainly with the evolution of the Himalaya south of the Main Mantle Thrust (MMT) and the Indus-Tsangpo suture zone, taking into account the neotectonic setting of northern Pakistan. Attention is given to subdivisions of the central Indian Himalaya, the transition from central Himalaya to northern Pakistan, subdivisions of the Himalaya of northern Pakistan, and aspects of neotectonics. Problems for future work are also discussed.

  13. Turbulence modelling of flow fields in thrust chambers

    Science.gov (United States)

    Chen, C. P.; Kim, Y. M.; Shang, H. M.

    1993-01-01

    Following the consensus of a workshop in Turbulence Modelling for Liquid Rocket Thrust Chambers, the current effort was undertaken to study the effects of second-order closure on the predictions of thermochemical flow fields. To reduce the instability and computational intensity of the full second-order Reynolds Stress Model, an Algebraic Stress Model (ASM) coupled with a two-layer near wall treatment was developed. Various test problems, including the compressible boundary layer with adiabatic and cooled walls, recirculating flows, swirling flows, and the entire SSME nozzle flow were studied to assess the performance of the current model. Detailed calculations for the SSME exit wall flow around the nozzle manifold were executed. As to the overall flow predictions, the ASM removes another assumption for appropriate comparison with experimental data to account for the non-isotropic turbulence effects.

  14. Data Archive and Portal Thrust Area Strategy Report

    Energy Technology Data Exchange (ETDEWEB)

    Sivaraman, Chitra; Stephan, Eric G.; Macduff, Matt C.; Hagler, Clay D.

    2014-09-30

    This report describes the Data Archive and Portal (DAP), a key capability of the U.S. Department of Energy's Atmosphere to Electron (A2e) initiative. The DAP Thrust Area Planning Group was organized to develop a plan for deploying this capability. Primarily, the report focuses on a distributed system--a DOE Wind Cloud--that functions as a repository for all A2e data. The Wind Cloud will be accessible via an open, easy-to-navigate user interface that facilitates community data access, interaction, and collaboration. DAP management will work with the community, industry, and international standards bodies to develop standards for wind data and to capture important characteristics of all data in the Wind Cloud.

  15. Thrust Measurements in Ballistic Pendulum Ablative Laser Propulsion Experiments

    Science.gov (United States)

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

    2008-04-01

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

  16. Data Archive and Portal Thrust Area Strategy Report

    Energy Technology Data Exchange (ETDEWEB)

    Sivaraman, Chitra [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephan, Eric G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Macduff, Matt C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hagler, Clay D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-01

    This report describes the Data Archive and Portal (DAP), a key capability of the U.S. Department of Energy's Atmosphere to Electron (A2e) initiative. The DAP Thrust Area Planning Group was organized to develop a plan for deploying this capability. Primarily, the report focuses on a distributed system--a DOE Wind Cloud--that functions as a repository for all A2e data. The Wind Cloud will be accessible via an open, easy-to-navigate user interface that facilitates community data access, interaction, and collaboration. DAP management will work with the community, industry, and international standards bodies to develop standards for wind data and to capture important characteristics of all data in the Wind Cloud.

  17. Procedure for utilizing the lift and thrust forces of ornithopters

    Science.gov (United States)

    Bezard, C.

    1985-01-01

    This procedure is distinguished by two beating wings which together describe, in space, a succession of interlaced triangles. On these wings, whose incidence varies automatically, identical forces are exerted: simultaneous lift and thrust when they make their descent, which is inclined toward the front of the craft, and lift alone when they make their ascent, which is inclined toward the rear of the craft and follows a slide horizontal movement. A mechanical device makes these movements possible. It includes: two wings with hollow profiles, connected by a framework located above a rigid frame and attached to it by bars with joints. These bars are moved with control rods which gear down the drive force. A mechanism with elastic bands or springs automatically varies the incidence of the wings.

  18. Thrusts and Prospects on Understanding and Predicting Asian Monsoon Climate

    Institute of Scientific and Technical Information of China (English)

    WANG Bin

    2008-01-01

    Development of monsoon climate prediction through integrated research efforts to improve our understanding of monsoon variability and predictability is a primary goal of the Asian Monsoon Years (2007-2011) and International Monsoon Study under the leadership of the World Climate Research Programme.The present paper reviews recent progress in Asian monsoon research focusing on (1) understanding and modeling of the monsoon variability, (2) determining the sources and limits of predictability, and (3) assessing the current status of climate prediction, with emphasis on the weekly to interannual time scales. Particular attention is paid to identify scientific issues and thrust areas, as well as potential directions to move forward in an attempt to stimulate future research to advance our understanding of monsoon climate dynamics and improve our capability to forecast Asian monsoon climate variation.

  19. Electric sail elliptic displaced orbits with advanced thrust model

    Science.gov (United States)

    Niccolai, Lorenzo; Quarta, Alessandro A.; Mengali, Giovanni

    2017-09-01

    This paper analyzes the performance of an Electric Solar Wind Sail for generating and maintaining an elliptic, heliocentric, displaced non-Keplerian orbit. In this sense, this paper extends and completes recent studies regarding the performances of an Electric Solar Wind Sail that covers a circular, heliocentric, displaced orbit of given characteristics. The paper presents the general equations that describe the elliptic orbit maintenance in terms of both spacecraft attitude and performance requirements, when a refined thrust model (recently proposed for the preliminary mission design) is taken into account. In particular, the paper also discusses some practical applications on particular mission scenarios in which an analytic solution of the governing equations has been found.

  20. Real-time seam tracking for rocket thrust chamber manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, D.J.; Novak, J.L. [Sandia National Labs., Albuquerque, NM (United States); Starr, G.P. [New Mexico Univ., Albuquerque, NM (United States); Maslakowski, J.E. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.

    1993-11-01

    A sensor-based control approach for real-time seam tracking of rocket thrust chamber assemblies has been developed to enable automation of a braze paste dispensing process. This approach utilizes a non-contact Multi-Axis Seam Tracking (MAST) sensor to track the seams. Thee MAST sensor measures capacitance variations between the sensor and the workpiece and produces four varying voltages which are read directly into the robot controller. A PID control algorithm which runs at the application program level has been designed based upon a simple dynamic model of the combined robot and sensor plant. The control algorithm acts on the incoming sensor signals in real-time to guide the robot motion along the seam path. Experiments demonstrate that seams can be tracked at 100 mm/sec within the accuracy required for braze paste dispensing.

  1. On the Design of Tilting-Pad Thrust Bearings

    DEFF Research Database (Denmark)

    Heinrichson, Niels

    2007-01-01

    Pockets are often machined in the surfaces of tilting-pad thrust bearings to allow for hydrostatic jacking in the start-up phase. Pockets and other recesses in the surfaces of bearing pads influence the pressure distribution and thereby the position of the pivot resulting in the most advantageous...... friction and a small pressure build-up. As in parallel-step bearings the recesses may also have a depth of the same order of magnitude as the oil film thickness. Such recesses are characterized by a strong pressure build-up caused by the reduction of the flow area at the end of the recess. Numerical models...... based on the Reynolds equation are used. They include the effects of variations of viscosity with temperature and the deformation of the bearing pads due to pressure and thermal gradients. The models are validated using measurements. Tilting-pad bearings of standard design are studied and the influences...

  2. Formation of chlorite during thrust fault reactivation. Record of fluid origin and P-T conditions in the Monte Perdido thrust fault (southern Pyrenees)

    Science.gov (United States)

    Lacroix, B.; Charpentier, D.; Buatier, M.; Vennemann, T.; Labaume, P.; Adatte, T.; Travé, A.; Dubois, M.

    2012-06-01

    The chemical and isotopic compositions of clay minerals such as illite and chlorite are commonly used to quantify diagenetic and low-grade metamorphic conditions, an approach that is also used in the present study of the Monte Perdido thrust fault from the South Pyrenean fold-and-thrust belt. The Monte Perdido thrust fault is a shallow thrust juxtaposing upper Cretaceous-Paleocene platform carbonates and Lower Eocene marls and turbidites from the Jaca basin. The core zone of the fault, about 6 m thick, consists of intensely deformed clay-bearing rocks bounded by major shear surfaces. Illite and chlorite are the main hydrous minerals in the fault zone. Illite is oriented along cleavage planes while chlorite formed along shear veins (<50 μm in thickness). Authigenic chlorite provides essential information about the origin of fluids and their temperature. δ18O and δD values of newly formed chlorite support equilibration with sedimentary interstitial water, directly derived from the local hanging wall and footwall during deformation. Given the absence of large-scale fluid flow, the mineralization observed in the thrust faults records the P-T conditions of thrust activity. Temperatures of chlorite formation of about 240°C are obtained via two independent methods: chlorite compositional thermometers and oxygen isotope fractionation between cogenetic chlorite and quartz. Burial depth conditions of 7 km are determined for the Monte Perdido thrust reactivation, coupling calculated temperature and fluid inclusion isochores. The present study demonstrates that both isotopic and thermodynamic methods applied to clay minerals formed in thrust fault are useful to help constrain diagenetic and low-grade metamorphic conditions.

  3. Momentum Management Tool for Low-Thrust Missions

    Science.gov (United States)

    Swenka, Edward R.; Smith, Brett A.; Vanelli, Charles A.

    2010-01-01

    A momentum management tool was designed for the Dawn low-thrust interplanetary spacecraft en route to the asteroids Vesta and Ceres, in an effort to better understand the early creation of the solar system. Momentum must be managed to ensure the spacecraft has enough control authority to perform necessary turns and hold a fixed inertial attitude against external torques. Along with torques from solar pressure and gravity-gradients, ion-propulsion engines produce a torque about the thrust axis that must be countered by the four reaction wheel assemblies (RWA). MomProf is a ground operations tool built to address these concerns. The momentum management tool was developed during initial checkout and early cruise, and has been refined to accommodate a wide range of momentum-management issues. With every activity or sequence, wheel speeds and momentum state must be checked to avoid undesirable conditions and use of consumables. MomProf was developed to operate in the MATLAB environment. All data are loaded into MATLAB as a structure to provide consistent access to all inputs by individual functions within the tool. Used in its most basic application, the Dawn momentum tool uses the basic principle of angular momentum conservation, computing momentum in the body frame, and RWA wheel speeds, for all given orientations in the input file. MomProf was designed specifically to be able to handle the changing external torques and frequent de - saturations. Incorporating significant external torques adds complexity since there are various external torques that act under different operational modes.

  4. Fuel-optimal low-thrust formation reconfiguration via Radau pseudospectral method

    Science.gov (United States)

    Li, Jing

    2016-07-01

    This paper investigates fuel-optimal low-thrust formation reconfiguration near circular orbit. Based on the Clohessy-Wiltshire equations, first-order necessary optimality conditions are derived from the Pontryagin's maximum principle. The fuel-optimal impulsive solution is utilized to divide the low-thrust trajectory into thrust and coast arcs. By introducing the switching times as optimization variables, the fuel-optimal low-thrust formation reconfiguration is posed as a nonlinear programming problem (NLP) via direct transcription using multiple-phase Radau pseudospectral method (RPM), which is then solved by a sparse nonlinear optimization software SNOPT. To facilitate optimality verification and, if necessary, further refinement of the optimized solution of the NLP, formulas for mass costate estimation and initial costates scaling are presented. Numerical examples are given to show the application of the proposed optimization method. To fix the problem, generic fuel-optimal low-thrust formation reconfiguration can be simplified as reconfiguration without any initial and terminal coast arcs, whose optimal solutions can be efficiently obtained from the multiple-phase RPM at the cost of a slight fuel increment. Finally, influence of the specific impulse and maximum thrust magnitude on the fuel-optimal low-thrust formation reconfiguration is analyzed. Numerical results shown the links and differences between the fuel-optimal impulsive and low-thrust solutions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ralston, D.R.

    1983-05-01

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

  6. Tongue Strength: Its Relationship to Tongue Thrusting, Open-Bite, and Articulatory Proficiency.

    Science.gov (United States)

    Dworkin, James P.; Culatta, Richard A.

    1980-01-01

    No significant differences in tongue strength were found between any of the three groups of 7- to 16-year old children: normal speaking with anterior tongue thrusting during swallow and open bite malocclusion, frontal lisping with anterior tongue thrusting during swallow and open bite malocclusion, and normal controls. (Author/DLS)

  7. Comparison of Thrust Characteristics in Pencil Sized Cylinder-type Linear Motors with Different Magnet Arrays

    OpenAIRE

    Nakaiwa, K; Yamada, A; Tashiro, K.; Wakiwaka, H.

    2009-01-01

    From a strong demand on the miniaturization of a chip mounter or a semiconductor device, the thrust improvement considering the magnets arrangement is studied. We accept a core stator with a Halbach type magnet array for a current linear motor. The thrust characteristics are compared with two kinds of mover, a NS magnet array and a Halbach magnet array.

  8. Experimental investigation of thrust augmentation by ejectors on a pulse detonation engine

    Directory of Open Access Journals (Sweden)

    Huang Xi-Qiao

    2015-01-01

    Full Text Available Utilizing gasoline as the fuel, air as oxidizer, a series of multi-cycle detonation experiments was conducted to study thrust augmentation by PDE-driven ejectors. The straight cylindrical ejectors with different inner diameter, length and inlet geometry were designed. The effects of the axial location of the ejectors relative to the end of the detonation tube, ejector length-to-diameter ratio on thrust augmentation were investigated, with the operating frequency of 25 Hz. A peak thrust augmentation level of 80.5% was achieved by adding an ejector to the exit of the detonation tube. Performance measurements of the PDE-ejector system showed that thrust augmentation is a strong function of the ejector axial position. The result indicated that there exists a maximum thrust augmentation with ejector upstream of the detonation tube exit at least. The exact location at which the maximum thrust augmentation was obtained varies with the ejector-to-PDE diameter ratio and the ejector inlet geometry. With the increase of the length-to-diameter ratio, thrust augmentation was noticeably enhanced and finally tended to a constant. There exists an optimum ejector length. In the present study, the optimum length-to-diameter ratio of ejector was 4.58. Furthermore, the effect of operating frequency on ejector thrust augmentation also investigated. The operating frequency was varied from 15 Hz to 35 Hz.

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

    Science.gov (United States)

    Wong, Andrea R; Toftul, Alexandra; Polzin, Kurt A; Pearson, J Boise

    2012-02-01

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

  10. A new method for optimization of low-thrust gravity-assist sequences

    Science.gov (United States)

    Maiwald, V.

    2017-09-01

    Recently missions like Hayabusa and Dawn have shown the relevance and benefits of low-thrust spacecraft concerning the exploration of our solar system. In general, the efficiency of low-thrust propulsion is one means of improving mission payload mass. At the same time, gravity-assist maneuvers can serve as mission enablers, as they have the capability to provide "free energy." A combination of both, gravity-assist and low-thrust propulsion, has the potential to generally improve mission performance, i.e. planning and optimization of gravity-assist sequences for low-thrust missions is a desirable asset. Currently no established methods exist to include the gravity-assist partners as optimization variable for low-thrust missions. The present paper explains how gravity-assists are planned and optimized, including the gravity-assist partners, for high-thrust missions and discusses the possibility to transfer the established method, based on the Tisserand Criterion, to low-thrust missions. It is shown how the Tisserand Criterion needs to be adapted using a correction term for the low-thrust situation. It is explained why this necessary correction term excludes an a priori evaluation of sequences and therefore their planning and an alternate approach is proposed. Preliminary results of this method, by application of a Differential Evolution optimization algorithm, are presented and discussed, showing that the method is valid but can be improved. Two constraints on the search space are briefly presented for that aim.

  11. Varus thrust and knee frontal plane dynamic motion in persons with knee osteoarthritis.

    Science.gov (United States)

    Chang, A H; Chmiel, J S; Moisio, K C; Almagor, O; Zhang, Y; Cahue, S; Sharma, L

    2013-11-01

    Varus thrust visualized during walking is associated with a greater medial knee load and an increased risk of medial knee osteoarthritis (OA) progression. Little is known about how varus thrust presence determined by visual observation relates to quantitative gait kinematic data. We hypothesized that varus thrust presence is associated with greater knee frontal plane dynamic movement during the stance phase of gait. Participants had knee OA in at least one knee. Trained examiners assessed participants for varus thrust presence during ambulation. Frontal plane knee motion during ambulation was captured using external passive reflective markers and an 8-camera motion analysis system. To examine the cross-sectional relationship between varus thrust and frontal plane knee motion, we used multivariable regression models with the quantitative motion measures as dependent variables and varus thrust (present/absent) as predictor; models were adjusted for age, gender, body mass index (BMI), gait speed, and knee static alignment. 236 persons [mean BMI: 28.5 kg/m(2) (standard deviation (SD) 5.5), mean age: 64.9 years (SD 10.4), 75.8% women] contributing 440 knees comprised the study sample. 82 knees (18.6%) had definite varus thrust. Knees with varus thrust had greater peak varus angle and greater peak varus angular velocity during stance than knees without varus thrust (mean differences 0.90° and 6.65°/s, respectively). These patterns remained significant after adjusting for age, gender, BMI, gait speed, and knee static alignment. Visualized varus thrust during walking was associated with a greater peak knee varus angular velocity and a greater peak knee varus angle during stance phase of gait. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  12. Structural evolution of the Yeongwol thrust system, northeastern Okcheon fold-thrust belt, Korea: Insights from structural interpretations and SHRIMP U-Pb and K-Ar geochronology

    Science.gov (United States)

    Jang, Yirang; Kwon, Sanghoon

    2017-04-01

    The NE-trending Okcheon Belt is a prominent fold-thrust belt preserved in the Korean Peninsula. In the Yeongwol area, the northeastern Okcheon Belt, the Cambrian-Ordovician (possibly to Silurian) Joseon Supergroup overlies the Carboniferous-Permian (possibly to early Triassic) Pyeongan Supergroup and/or Jurassic Bansong Group by N-S trending thrust faults, having highly connected traces in map view. To understand the structural geometry of these thrust faults and their evolution history, we have conducted structural analyses, together with SHRIMP U-Pb zircon and K-Ar illite age datings. The results show that (1) the thrusts in the Yeongwol area, carrying the lower Paleozoic strata over the upper Paleozoic or Mesozoic strata, are defined as the Yeongwol thrust system. The closed-loops map patterns of this system can further be interpreted by alternative duplex models in terms of a hinterland dipping duplex vs. a combination of major thrusts and connecting splays; (2) newly obtained SHRIMP U-Pb zircon ages from a dike and synorogenic sediments and K-Ar illite ages from fault gouges, together with previously reported evidences form the Yeongwol area, suggest multiple events after Permo-Triassic to early Neogene. The SHRIMP U-Pb detrital zircon ages from the lower Paleozoic rocks of the Yeongwol area can provide tectono-stratigraphic information of this area before the Permian. These further indicate the broader implications in that how detailed structural interpretations supported by the geochronological data can help to understand the tectonic evolution of the Okcheon Belt as well as the fold-thrust belts in general.

  13. Lithological and structural investigations of the Finero back thrust

    Science.gov (United States)

    Palzer, M.; Österle, J.; Klötzli, U.

    2012-04-01

    complex". New lithological and structural investigations show, that the former assumption of an Alpine back thrust south of the peridotite body of Finero has to be questioned. Field work and petrography was focused on lithological boundaries, high-T shear zones and the distinction of "internal gabbro" and "external gabbro". Our findings reveal distinct discrepancies to older mapping and interpretations. It can be shown, that the contacts between "external gabbro" and hornblende peridotite are high-temperature features and structurally far more complicate than previously supposed which makes greenschist facies Alpine back thrusting most unlikely. The contacts almost certainly are magmatic or at least formed at mantle temperatures. They are thus pre-Alpine in age. Alternatively to the back thrust model, we present a model of a folded multi-layered peridotite body which seems to be inter fingered with the "external gabbro". Our findings definitely corroborate the possibility that the "internal gabbro", the hornblende peridotite and the "external gabbro" form a single magmatic series.

  14. Recent Mega-Thrust Tsunamigenic Earthquakes and PTHA

    Science.gov (United States)

    Lorito, S.

    2013-05-01

    The occurrence of several mega-thrust tsunamigenic earthquakes in the last decade, including but not limited to the 2004 Sumatra-Andaman, the 2010 Maule, and 2011 Tohoku earthquakes, has been a dramatic reminder of the limitations in our capability of assessing earthquake and tsunami hazard and risk. However, the increasingly high-quality geophysical observational networks allowed the retrieval of most accurate than ever models of the rupture process of mega-thrust earthquakes, thus paving the way for future improved hazard assessments. Probabilistic Tsunami Hazard Analysis (PTHA) methodology, in particular, is less mature than its seismic counterpart, PSHA. Worldwide recent research efforts of the tsunami science community allowed to start filling this gap, and to define some best practices that are being progressively employed in PTHA for different regions and coasts at threat. In the first part of my talk, I will briefly review some rupture models of recent mega-thrust earthquakes, and highlight some of their surprising features that likely result in bigger error bars associated to PTHA results. More specifically, recent events of unexpected size at a given location, and with unexpected rupture process features, posed first-order open questions which prevent the definition of an heterogeneous rupture probability along a subduction zone, despite of several recent promising results on the subduction zone seismic cycle. In the second part of the talk, I will dig a bit more into a specific ongoing effort for improving PTHA methods, in particular as regards epistemic and aleatory uncertainties determination, and the computational PTHA feasibility when considering the full assumed source variability. Only logic trees are usually explicated in PTHA studies, accounting for different possible assumptions on the source zone properties and behavior. The selection of the earthquakes to be actually modelled is then in general made on a qualitative basis or remains implicit

  15. Thrust vector control of upper stage with a gimbaled thruster during orbit transfer

    Science.gov (United States)

    Wang, Zhaohui; Jia, Yinghong; Jin, Lei; Duan, Jiajia

    2016-10-01

    In launching Multi-Satellite with One-Vehicle, the main thruster provided by the upper stage is mounted on a two-axis gimbal. During orbit transfer, the thrust vector of this gimbaled thruster (GT) should theoretically pass through the mass center of the upper stage and align with the command direction to provide orbit transfer impetus. However, it is hard to be implemented from the viewpoint of the engineering mission. The deviations of the thrust vector from the command direction would result in large velocity errors. Moreover, the deviations of the thrust vector from the upper stage mass center would produce large disturbance torques. This paper discusses the thrust vector control (TVC) of the upper stage during its orbit transfer. Firstly, the accurate nonlinear coupled kinematic and dynamic equations of the upper stage body, the two-axis gimbal and the GT are derived by taking the upper stage as a multi-body system. Then, a thrust vector control system consisting of the special attitude control of the upper stage and the gimbal rotation of the gimbaled thruster is proposed. The special attitude control defined by the desired attitude that draws the thrust vector to align with the command direction when the gimbal control makes the thrust vector passes through the upper stage mass center. Finally, the validity of the proposed method is verified through numerical simulations.

  16. Mylonitic volcanics near Puging, Upper Siang district, Arunachal Pradesh: Evidence of oblique-slip thrusting

    Indian Academy of Sciences (India)

    T K Goswami; P Bhattacharyya; D Bezbaruah

    2016-08-01

    The Abor volcanics of the continental flood basalt affinity are extensively exposed in different parts of the Siang valley. These are associated with Yinkiong Group of rocks of Paleocene–Eocene age and represent syn-sedimentary volcanism in a rift setting. Subsequent folding and thrusting of the Siyom and Rikor sequences above the Yinkiong Group of rocks represent changes from syn-to-post collisionalbrittle-ductile tectonic episodes. Mylonitic Abor volcanics in the thrust contacts are studied at several locations in the north and south of Puging in the Siang valley. Both the Abor volcanics and associated Rikor and Yinkiong Group of rocks preserve meso to micro-scale fabric asymmetries indicating that the thrust contacts are shear zones of brittle-ductile nature containing mylonitic textures of high shear strain.Two distinct hitherto unrecognised shear zones in the north and south of Puging are named as North Puging Shear Zone (NPSZ) and South Puging Shear Zone (SPSZ). The kinematic indicators along the thrust contact indicate oblique slip thrusting of the Rikor and Siyom thrust sheets above the Yinkiong Group of rocks. This paper provides field evidence proving that the compression due the Burmese plate made oblique slip thrusting and zones of mylonitised volcanics possible and associated metasediments were formed. The kinematic indicators in the NPSZ and SPSZ respectively indicate top-to-SSE and top-to-NNW sense of shears.

  17. Jaw thrust as a predictor of insertion conditions for the proseal laryngeal mask airway.

    Science.gov (United States)

    Townsend, Russell; Brimacombe, Joseph; Keller, Christian; Wenzel, Volker; Herff, Holger

    2009-02-01

    We test the hypothesis that the response to jaw thrust is an effective predictor of insertion conditions for the ProSeal laryngeal mask airway (ProSeal LMA). One hundred and sixty patients (ASA grade 1-3, aged >18 yr) were studied. Five anesthetists blinded to the response to jaw thrust participated in the study, each performed >30 insertions. Induction of anesthesia was with propofol titrated to loss of lash reflex and apnea. A standard amount of jaw thrust was applied and any motor response noted by three observers. The ProSeal LMA was inserted using the standard digital technique. Insertion conditions were considered optimal if there was no motor or upper airway reflex response to insertion. There was no response to jaw thrust in 86% (137/160) of patients and insertion was optimal in 76% (121/160) of patients. A response to jaw thrust predicted suboptimal insertion conditions in 74% (17/23) and a lack of response predicted optimal insertion conditions in 84% (115/137). The accuracy, sensitivity and specificity were 0.82, 0.95 and 0.44, respectively. We conclude thatjaw thrust is a reliable predictor of insertion conditions for the ProSeal LMA with the digital insertion technique after induction of anesthesia with propofol. We suggest that clinicians learn how to apply the correct amount of jaw thrust and perform this test routinely.

  18. Effect of jaw thrust and cricoid pressure maneuvers on glottic visualization during GlideScope videolaryngoscopy.

    Science.gov (United States)

    Corda, David M; Riutort, Kevin T; Leone, Alex J; Qureshi, Mueez K; Heckman, Michael G; Brull, Sorin J

    2012-06-01

    During performance of direct laryngoscopy in the difficult-to-visualize airway, several maneuvers have the potential to impact glottic visualization, including jaw thrust and cricoid pressure. The effect of these maneuvers on glottic visualization during videolaryngoscopy has not been studied. We evaluated the effect of jaw thrust and cricoid pressure maneuvers on both visualization of the glottis and the area of glottic opening visible during GlideScope-aided videolaryngoscopy. One hundred patients were enrolled in this study. After induction of general anesthesia, videolaryngoscopy was followed by jaw thrust and cricoid pressure maneuvers performed in random order. Laryngeal anatomy was recorded continuously and was saved as digital images following the initial laryngoscopy and after each maneuver. Glottis grade [modified Cormack and Lehane (C&L)] was recorded, as was the total glottic area. There was improvement in glottis grade when utilizing jaw thrust maneuver in comparison to GlideScope videolaryngoscopy alone (31% improved, 4% worsened; P thrust maneuver in comparison with videolaryngoscopy alone (P thrust maneuver was superior to videolaryngoscopy alone in improving the modified C&L grade and the visualized glottic area; however, no significant improvement was noted with cricoid pressure. We therefore recommend the use of jaw thrust as a first-line maneuver to aid in glottic visualization and tracheal intubation during GlideScope videolaryngoscopy.

  19. Effect of Jaw Thrust on Transesophageal Echocardiography Probe Insertion and Concomitant Oropharyngeal Injury.

    Science.gov (United States)

    Chang, Jee-Eun; Min, Seong-Won; Kim, Chong-Soo; Lee, Jung-Man; No, Hyunjoung; Hwang, Jin-Young

    2015-10-01

    The aim of this study was to evaluate the effect of jaw thrust on transesophageal echocardiography probe insertion and concomitant oropharyngeal injury. A prospective, randomized study Medical center governed by a university hospital Forty-two adult patients undergoing cardiovascular surgery were included. After the induction of anesthesia, a transesophageal echocardiography probe was inserted using an anterior jaw lift technique (conventional group, n = 21) or a jaw thrust-assisted technique (jaw thrust group, n = 21). The incidence of oropharyngeal injury, number of insertion attempts, blood on the probe tip, and presence of persistent oropharyngeal bleeding were evaluated. In the conventional group, oropharyngeal injury occurred more frequently than in the jaw-thrust group (52.4% v 9.5%, respectively; p = 0.006). Regarding transesophageal echocardiography probe insertion, the conventional group required more attempts than the jaw-thrust group (p = 0.043). The incidence of blood on the probe tip was higher in the conventional group than in the jaw-thrust group (p = 0.020), but the presence of persistent oropharyngeal bleeding was similar between the 2 groups. The jaw-thrust maneuver facilitated the insertion of the transesophageal echocardiography probe and reduced concomitant oropharyngeal injury. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Independent cough flow augmentation by glossopharyngeal breathing plus table thrust in muscular dystrophy.

    Science.gov (United States)

    Bianchi, Carlo; Carrara, Raniero; Khirani, Sonia; Tuccio, Maria Chiara

    2014-01-01

    The purpose of the present study was to compare the unassisted cough peak flow (CPF) of patients affected by muscular dystrophy with CPF augmented by various techniques, including maximal depth glossopharyngeal breathing (GPB) combined with a subsequent self-induced thoracic or abdominal thrust. All of the motorized wheelchair-dependent patients with muscular dystrophy who had previously mastered GPB were trained at home to increase their cough efficacy. This training involved maneuvering their wheelchair against the edge of a specially built table to autonomously produce a thoracic and/or abdominal thrust timed to the opening of the glottis for an independently assisted cough. Both unassisted and variously assisted CPFs were compared. The 18 patients (17 men/1 woman) with muscular dystrophy, aged 21.1 ± 5.4 yrs, achieved variously assisted CPFs that were significantly higher than the spontaneous CPF (P thrust (326.4 ± 79.5 liters/min) or by GPB and thoracoabdominal thrust (326.4 ± 87.5 liters/min) were not significantly different (P = 0.07) from the CPFs independently attained by GPB plus independently maneuvering a wheelchair for a table thrust (310.3 ± 74.7 liters/min). The independently assisted (GPB plus table thrust) CPF was comparable to the CPFs that required personal assistance for air stacking and abdominal thrusts. Therefore, for patients with muscular dystrophy, this physical medicine technique and cough-assisted techniques that require personal intervention are strongly recommended.

  1. Computational Study of an Axisymmetric Dual Throat Fluidic Thrust Vectoring Nozzle for a Supersonic Aircraft Application

    Science.gov (United States)

    Deere, Karen A.; Flamm, Jeffrey D.; Berrier, Bobby L.; Johnson, Stuart K.

    2007-01-01

    A computational investigation of an axisymmetric Dual Throat Nozzle concept has been conducted. This fluidic thrust-vectoring nozzle was designed with a recessed cavity to enhance the throat shifting technique for improved thrust vectoring. The structured-grid, unsteady Reynolds- Averaged Navier-Stokes flow solver PAB3D was used to guide the nozzle design and analyze performance. Nozzle design variables included extent of circumferential injection, cavity divergence angle, cavity length, and cavity convergence angle. Internal nozzle performance (wind-off conditions) and thrust vector angles were computed for several configurations over a range of nozzle pressure ratios from 1.89 to 10, with the fluidic injection flow rate equal to zero and up to 4 percent of the primary flow rate. The effect of a variable expansion ratio on nozzle performance over a range of freestream Mach numbers up to 2 was investigated. Results indicated that a 60 circumferential injection was a good compromise between large thrust vector angles and efficient internal nozzle performance. A cavity divergence angle greater than 10 was detrimental to thrust vector angle. Shortening the cavity length improved internal nozzle performance with a small penalty to thrust vector angle. Contrary to expectations, a variable expansion ratio did not improve thrust efficiency at the flight conditions investigated.

  2. Static Thrust and Vectoring Performance of a Spherical Convergent Flap Nozzle with a Nonrectangular Divergent Duct

    Science.gov (United States)

    Wing, David J.

    1998-01-01

    The static internal performance of a multiaxis-thrust-vectoring, spherical convergent flap (SCF) nozzle with a non-rectangular divergent duct was obtained in the model preparation area of the Langley 16-Foot Transonic Tunnel. Duct cross sections of hexagonal and bowtie shapes were tested. Additional geometric parameters included throat area (power setting), pitch flap deflection angle, and yaw gimbal angle. Nozzle pressure ratio was varied from 2 to 12 for dry power configurations and from 2 to 6 for afterburning power configurations. Approximately a 1-percent loss in thrust efficiency from SCF nozzles with a rectangular divergent duct was incurred as a result of internal oblique shocks in the flow field. The internal oblique shocks were the result of cross flow generated by the vee-shaped geometric throat. The hexagonal and bowtie nozzles had mirror-imaged flow fields and therefore similar thrust performance. Thrust vectoring was not hampered by the three-dimensional internal geometry of the nozzles. Flow visualization indicates pitch thrust-vector angles larger than 10' may be achievable with minimal adverse effect on or a possible gain in resultant thrust efficiency as compared with the performance at a pitch thrust-vector angle of 10 deg.

  3. Non-Contact Thrust Stand Calibration Method for Repetitively-Pulsed Electric Thrusters

    Science.gov (United States)

    Wong, Andrea R.; Toftul, Alexandra; Polzin, Kurt A.; Pearson, J. Boise

    2011-01-01

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

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

    Science.gov (United States)

    Flamm, Jeffrey D.; Deere, Karen A.; Mason, Mary L.; Berrier, Bobby L.; Johnson, Stuart K.

    2006-01-01

    A Dual Throat Nozzle fluidic thrust vectoring technique that achieves higher thrust-vectoring efficiencies than other fluidic techniques, without sacrificing thrust efficiency has been developed at NASA Langley Research Center. The nozzle concept was designed with the aid of the structured-grid, Reynolds-averaged Navier-Stokes computational fluidic dynamics code PAB3D. This new concept combines the thrust efficiency of sonic-plane skewing with increased thrust-vectoring efficiencies obtained by maximizing pressure differentials in a separated cavity located downstream of the nozzle throat. By injecting secondary flow asymmetrically at the upstream minimum area, a new aerodynamic minimum area is formed downstream of the geometric minimum and the sonic line is skewed, thus vectoring the exhaust flow. The nozzle was tested in the NASA Langley Research Center Jet Exit Test Facility. Internal nozzle performance characteristics were defined for nozzle pressure ratios up to 10, with a range of secondary injection flow rates up to 10 percent of the primary flow rate. Most of the data included in this paper shows the effect of secondary injection rate at a nozzle pressure ratio of 4. The effects of modifying cavity divergence angle, convergence angle and cavity shape on internal nozzle performance were investigated, as were effects of injection geometry, hole or slot. In agreement with computationally predicted data, experimental data verified that decreasing cavity divergence angle had a negative impact and increasing cavity convergence angle had a positive impact on thrust vector angle and thrust efficiency. A curved cavity apex provided improved thrust ratios at some injection rates. However, overall nozzle performance suffered with no secondary injection. Injection holes were more efficient than the injection slot over the range of injection rates, but the slot generated larger thrust vector angles for injection rates less than 4 percent of the primary flow rate.

  5. Study of Daedalus Interstellar Spacecraft Reaction Chamber and Thrust Structure

    Science.gov (United States)

    Reddy, S. K.; Benaroya, H.

    Project Daedalus was the 1978 trade study that proved the feasibility of space travel utilizing fusion-based propulsion (Inertial Confinement Fusion). This paper analyzes some of the key structural aspects of the Daedalus spacecraft, in particular, the reaction chamber and thrust structure that is integral to the Daedalus spacecraft, which supports the loads resulting from the fusion reactions. First, the reaction chamber is studied computationally in terms of static loading and vibrational characteristics utilizing the finite element method. Next, a proposed bracing system is integrated into the reaction chamber and the effects are studied. Lastly, the field coils with their supporting truss structure are added to the assembly. Concepts are introduced for actuators and course-correction mechanisms that ensure the spacecraft maintains the required trajectory to rendezvous with the target system. Present-day materials and manufacturing considerations are explored based on the assumptions made in the Daedalus study. Testing, qualification, and assembly of the spacecraft are also discussed. This paper is a summary of the first author's Master's Thesis at Rutgers University.

  6. Experimental status of thrusting by electromagnetic inertia manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Brito, H.H. [Instituto Universitario, Cordoba (Argentina)

    2004-04-01

    It has been shown in previous works that given suitable charge and current distributions, the electromagnetic (EM) field can modify the inertial properties of the generating device if Minkowski's energy-momentum tensor holds for the description of field-matter interactions. The possibility then arises of obtaining mechanical impulses on the device, not undergoing any exchange of mass-energy with the surrounding medium, by EM inertia manipulation (EMIM). The aim of this paper is to present the accumulated experimental evidence about that means of achieving thrust. Three test series performed during the periods 1993-1997 and 1999-2000 on different experimental setups, are reviewed from the viewpoint of an identification of systematic spurious effects. A fourth series of tests recently conducted yields results that can hardly be explained without the EMIM mechanism. However, they are in contradiction with null results predicted by the currently admitted formulation of global EM forces. Further progress along this line of research will likely require improved test and measurement procedures, to get rid of residual spurious effects. Enhanced reliability of the reported results is also expected to arise from independent confirmation by other researchers. (author)

  7. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    Science.gov (United States)

    Scarritt, Sara K.; Marchand, Belinda G.; Weeks, Michael W.

    2009-01-01

    In earlier investigations, the adaptation and implementation of a modified two-level corrections process as the onboard targeting algorithm for the Trans-Earth Injection phase of Orion is presented. The objective of that targeting algorithm is to generate the times of ignition and magnitudes of the required maneuvers such that the desired state at entry interface is achieved. In an actual onboard flight software implementation, these times of ignition and maneuvers are relayed onto Flight Control for command and execution. Although this process works well when the burn durations or burn arcs are small, this might not be the case during a contingency situation when lower thrust engines are employed to perform the maneuvers. Therefore, a new version of the modified two-level corrections process is formulated to handle the case of finite burn arcs. This paper presents the development and formulation of that finite burn modified two-level corrections process which can again be used as an onboard targeting algorithm for the Trans-Earth Injection phase of Orion. Additionally, performance results and a comparison between the two methods are presented. The finite burn two-level corrector formulation presented here ensures the entry constraints at entry interface are still met without violating the available fuel budget, while still accounting for much longer burn times in its design.

  8. The Star Thrust Experiment, FRC Formation and Sustainment Using RMF

    Science.gov (United States)

    Miller, Kenneth; Slough, John

    1998-11-01

    The same qualities that make the FRC attractive as a terrestrial power source make them even more attractive as a fusion engine for space missions due to strict constraints on size, complexity and weight. The first step toward attaining a viable FRC reactor/propulsion unit is the development of a simplified formation process that allows for subsequent sustainment. The Star Thrust Experiment (STX) has been designed to do this using a 50G 330 kHz Rotating Magnetic Field (RMF) for current drive. Two 10 MW solid state supplies (IGBT switched) drive the RMF antennas for milliseconds through a 20:1 99% efficient air core transformer. The 2 m long by 0.35 m radius RMF antennas are the inductors of LC resonant circuits. With Q ~ 60, the square wave IGBT output is filtered into a clean sinusoid, and 60 MW of circulating power is attained. Solenoidal magnets create ~ 1 kG axial confining field in the STX vacuum chamber, a 3 m long by 0.4 m diameter quartz tube. An axial discharge, 100 MW Alfven heater, and confining field reversal are available for plasma ionization and heating. At densities of 10^20 m-3, temperatures of ~ 15 eV are needed for RMF field penetration and effective current drive. Major system development and construction has been completed, and initial operation has begun. Supported by NASA and USDOE.

  9. Low-Thrust Many-Revolution Trajectory Optimization via Differential Dynamic Programming and a Sundman Transformation

    Science.gov (United States)

    Aziz, Jonathan D.; Parker, Jeffrey S.; Scheeres, Daniel J.; Englander, Jacob A.

    2017-01-01

    Low-thrust trajectories about planetary bodies characteristically span a high count of orbital revolutions. Directing the thrust vector over many revolutions presents a challenging optimization problem for any conventional strategy. This paper demonstrates the tractability of low-thrust trajectory optimization about planetary bodies by applying a Sundman transformation to change the independent variable of the spacecraft equations of motion to the eccentric anomaly and performing the optimization with differential dynamic programming. Fuel-optimal geocentric transfers are shown in excess of 1000 revolutions while subject to Earths J2 perturbation and lunar gravity.

  10. Thrust estimator design based on least squares support vector regression machine

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yong-ping; SUN Jian-guo

    2010-01-01

    In order to realize direct thrust control instead of traditional sensor-based control for nero-engines,it is indispensable to design a thrust estimator with high accuracy,so a scheme for thrust estimator design based on the least square support vector regression machine is proposed to solve this problem.Furthermore,numerical simulations confirm the effectiveness of our presented scheme.During the process of estimator design,a wrap per criterion that can not only reduce the computational complexity but also enhance the generalization performance is proposed to select variables as input variables for estimator.

  11. Is tongue thrust that develops during orthodontic treatment an unrecognized potential road block?

    Directory of Open Access Journals (Sweden)

    Chawla H

    2006-06-01

    Full Text Available The role of tongue thrust has often been suspected, long debated and largely dispelled as a primary etiological factor of malocclusion. However, tongue thrust may contribute to poor occlusal intercuspation both during and after treatment. A tongue thrust may also develop during orthodontic mechanotherapy as a result of the transient creation of intra and interarch spaces and this little recognized phenomenon was found to occur in many randomly followed cases. In many instances, this seemingly adaptive and secondary response of the tongue posture and function may persist and thereafter impede the resolution of intra and interarch problems.

  12. Static performance of an axisymmetric nozzle with post-exit vanes for multiaxis thrust vectoring

    Science.gov (United States)

    Berrier, Bobby L.; Mason, Mary L.

    1988-01-01

    An investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to determine the flow-turning capability and the nozzle internal performance of an axisymmetric convergent-divergent nozzle with post-exit vanes installed for multiaxis thrust vectoring. The effects of vane curvature, vane location relative to the nozzle exit, number of vanes, and vane deflection angle were determined. A comparison of the post-exit-vane thrust-vectoring concept with other thrust-vectoring concepts is provided. All tests were conducted with no external flow, and nozzle pressure ratio was varied from 1.6 to 6.0.

  13. Thrust duplex deformation in the volcaniclastic sequence of the Fatima fold-and-thrust belt in the west-central Arabian Shield

    Science.gov (United States)

    El-Shafei, Mohamed K.

    2017-05-01

    In this study, we present a field-based structural analysis of the unmetamorphosed Precambrian volcaniclastic sequences of the west-central Arabian Shield. The study area is known as the Fatima fold-and-thrust belt, which is an overturned synclinorium that developed during the Neoproterozoic era. This belt is composed primarily of green mudstone, green sandstone, an andesite flow, limestone, red mudstone and pyroclastic units. This stratigraphic succession, which presents different rheological multilayers, offers significant mesoscale folding and thrust-related structures. Mechanical anisotropy and thickness contrasts have played significant roles in controlling the style of the deformation. Deformed hinge zones, a simple duplex, a domino-style duplex, and imbricated and antiformal stacks are among the thrust-related structures presented and analyzed. The domino-style duplex observed on the backlimbs of the overturned anticlines formed a unique pattern that developed during thrust propagation. The results of this study indicate that the thrust duplex developed according to a thick-skinned model, and it represents a newly recognized tectonic regime in the Arabian Shield. Comprehensive field mapping and structural analyses revealed that the zone under study area was affected by four phases of deformation (D1-D4). The D1 and D2 phases present ductile deformation that developed during the final cratonization and assembly of the Arabian Shield, and they can be recognized at both the map and outcrop scales. The D1 phase represents a progressive regime and is indicated by a NW-SE stress orientation and the formation of a series of coaxial symmetrical NE-SW-plunging folds. NNW-directed thrust-related structures progressively developed during the D2 phase. An approximately fifty-three percent tectonic shortening can be calculated based on the restored structures. D3 and D4 have a brittle nature and are indicated by shearing and normal faulting, respectively.

  14. Similar Effects of Thrust and Non-Thrust Spinal Manipulation Found in Adults With Subacute and Chronic Low Back Pain – A Controlled Trial with Adaptive Allocation

    Science.gov (United States)

    Xia, Ting; Long, Cynthia R.; Gudavalli, Maruti R.; Wilder, David G.; Vining, Robert D.; Rowell, Robert M.; Reed, William R.; DeVocht, James W.; Goertz, Christine M.; Owens, Edward F.; Meeker, William C.

    2015-01-01

    Study Design A three-arm controlled trial with adaptive allocation. Objectives The aim of this study was to compare short-term effects of a side-lying, thrust spinal manipulation (SM) procedure and a non-thrust, flexion-distraction SM procedure in adults with subacute or chronic low back pain (LBP) over 2 weeks. Summary of Background Data SM has been recommended in recently published clinical guidelines for LBP management. Previous studies suggest that thrust and non-thrust SM procedures, though distinctly different in joint loading characteristics, have similar effects on patients with LBP. Methods Participants were eligible if they were 21-54 years old, had LBP for at least 4 weeks, scored 6 or above on the Roland-Morris disability questionnaire, and met the diagnostic classification of 1, 2, or 3 according to the Quebec Task Force Classification for Spinal Disorders. Participants were allocated in a 3:3:2 ratio to 4 sessions of thrust or non-thrust SM procedures directed at the lower lumbar and pelvic regions, or to a 2-week wait list control. The primary outcome was LBP-related disability using Roland-Morris disability questionnaire and the secondary outcomes were LBP intensity using visual analog scale, Fear-Avoidance Beliefs Questionnaire, and the 36-Item Short Form Health Survey. The study was conducted at the Palmer Center for Chiropractic Research with care provided by experienced doctors of chiropractic. Clinicians and patients were not blinded to treatment group. Results Of 192 participants enrolled, the mean age was 40 years and 54% were male. Improvement in disability, LBP intensity, Fear-Avoidance Beliefs Questionnaire – work subscale, and 36-Item Short Form Health Survey – physical health summary measure for the two SM groups were significantly greater than the control group. No difference in any outcomes was observed between the two SM groups. Conclusions Thrust and non-thrust SM procedures with distinctly different joint loading characteristics

  15. Low-Thrust Trajectory Optimization with Simplified SQP Algorithm

    Science.gov (United States)

    Parrish, Nathan L.; Scheeres, Daniel J.

    2017-01-01

    The problem of low-thrust trajectory optimization in highly perturbed dynamics is a stressing case for many optimization tools. Highly nonlinear dynamics and continuous thrust are each, separately, non-trivial problems in the field of optimal control, and when combined, the problem is even more difficult. This paper de-scribes a fast, robust method to design a trajectory in the CRTBP (circular restricted three body problem), beginning with no or very little knowledge of the system. The approach is inspired by the SQP (sequential quadratic programming) algorithm, in which a general nonlinear programming problem is solved via a sequence of quadratic problems. A few key simplifications make the algorithm presented fast and robust to initial guess: a quadratic cost function, neglecting the line search step when the solution is known to be far away, judicious use of end-point constraints, and mesh refinement on multiple shooting with fixed-step integration.In comparison to the traditional approach of plugging the problem into a “black-box” NLP solver, the methods shown converge even when given no knowledge of the solution at all. It was found that the only piece of information that the user needs to provide is a rough guess for the time of flight, as the transfer time guess will dictate which set of local solutions the algorithm could converge on. This robustness to initial guess is a compelling feature, as three-body orbit transfers are challenging to design with intuition alone. Of course, if a high-quality initial guess is available, the methods shown are still valid.We have shown that endpoints can be efficiently constrained to lie on 3-body repeating orbits, and that time of flight can be optimized as well. When optimizing the endpoints, we must make a trade between converging quickly on sub-optimal endpoints or converging more slowly on end-points that are arbitrarily close to optimal. It is easy for the mission design engineer to adjust this trade based on

  16. Low thrust chemical orbit to orbit propulsion system propellant management study

    Science.gov (United States)

    Dergance, R. H.; Hamlyn, K. M.; Tegart, J. R.

    1981-01-01

    Low thrust chemical propulsion systems were sized for transfer of large space systems from LEO to GEO. The influence of propellant combination, tankage and insulation requirements, and propellant management techniques on the LTPS mass and volume were studied. Liquid oxygen combined with hydrogen, methane or kerosene were the propellant combinations. Thrust levels of 445, 2230, and 4450 N were combined with 1, 4 and 8 perigee burn strategies. This matrix of systems was evaluated using multilayer insulation and spray-on-foam insulation systems. Various combinations of toroidal, cylindrical with ellipsoidal domes, and ellipsoidal tank shapes were investigated. Results indicate that low thrust (445 N) and single perigee burn approaches are considerably less efficient than the higher thrust level and multiple burn strategies. A modified propellant settling approach minimized propellant residuals and decreased system complexity, in addition, the toroid/ellipsoidal tank combination was predicted to be shortest.

  17. Effectiveness of Nitrous Oxide as a Liquid Injection Thrust Vector Control Fluid Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nitrous Oxide is proposed as an energetic liquid injection thrust vector control fluid for vehicle attitude control during dynamic vehicle maneuvers. Pulled from the...

  18. Low-Cost and Light-Weight Transpiration-Cooled Thrust Chambers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed effort aims to evaluate the feasibility of using transpiration-cooled Titanium as the primary material in small-scale thrust chambers for in-space...

  19. A Simple Method to Measure Nematodes' Propulsive Thrust and the Nematode Ratchet.

    Science.gov (United States)

    Bau, Haim; Yuan, Jinzhou; Raizen, David

    2015-11-01

    Since the propulsive thrust of micro organisms provides a more sensitive indicator of the animal's health and response to drugs than motility, a simple, high throughput, direct measurement of the thrust is desired. Taking advantage of the nematode C. elegans being heavier than water, we devised a simple method to determine the propulsive thrust of the animals by monitoring their velocity when swimming along an inclined plane. We find that the swimming velocity is a linear function of the sin of the inclination angle. This method allows us to determine, among other things, the animas' propulsive thrust as a function of genotype, drugs, and age. Furthermore, taking advantage of the animals' inability to swim over a stiff incline, we constructed a sawteeth ratchet-like track that restricts the animals to swim in a predetermined direction. This research was supported, in part, by NIH NIA Grant 5R03AG042690-02.

  20. Low-Thrust Transfer Design of Low-Observable Geostationary Earth Orbit Satellite

    Directory of Open Access Journals (Sweden)

    Bing Hua

    2015-01-01

    Full Text Available With radar and surface-to-air missiles posing an increasing threat to on-orbit spacecraft, low-observable satellites play an important role in low-thrust transfers. This paper presents the design for a low-thrust geostationary earth orbit (GEO transfer control strategy which takes into consideration the low-observable constraint and discusses Earth shadow and perturbation. A control parameter optimization addresses the orbit transfer problem, and five thrust modes are used. Simulation results show that the method outlined in this paper is simple and feasible and results in reduced transfer time with a small amount of calculation. The method therefore offers a useful reference for low-thrust GEO transfer design.

  1. Precise timing of the Early Paleozoic metamorphism and thrust deformation in the Eastern Kunlun Orogen

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In Dulan County, Qinghai Province NW China, the arc volcanic sequences in the northern side of the Central Fault of the East Kunlun were metamorphosed progressively from upper greenschist facies in the south to epidote-amphibolite facies in the north. High-angle thrust deforma-tion was developed synchronously with the peak metamor-phim and superimposed with later low-angle striking-slip deformation. Zircon U-Pb dating yields a concordant age of (448 ± 4) Ma for the metavolcanics. Syn-kinematic horn-blende and muscovite separated from the high-angle thrust-ing belt give 40Ar-39Ar plateau age of (427 ± 4) Ma and 408 Ma, respectively. These results precisely constrain the timing of the closure of early Paleozoic volcanic basin (Proto-Tethys) over the eastern portion of the East Kunlun Orogen, and the thrust tectonic slice had a cool rate of ca. 9℃/Ma.

  2. Note: Radial-thrust combo metal mesh foil bearing for microturbomachinery.

    Science.gov (United States)

    Park, Cheol Hoon; Choi, Sang Kyu; Hong, Doo Euy; Yoon, Tae Gwang; Lee, Sung Hwi

    2013-10-01

    This Note proposes a novel radial-thrust combo metal mesh foil bearing (MMFB). Although MMFBs have advantages such as higher stiffness and damping over conventional air foil bearings, studies related to MMFBs have been limited to radial MMFBs. The novel combo MMFB is composed of a radial top foil, thrust top foils, and a ring-shaped metal mesh damper--fabricated by compressing a copper wire mesh--with metal mesh thrust pads for the thrust bearing at both side faces. In this study, the combo MMFB was fabricated in half-split type to support the rotor for a micro gas turbine generator. The manufacture and assembly process for the half-split-type combo MMFB is presented. In addition, to verify the proposed combo MMFB, motoring test results up to 250,000 rpm and axial displacements as a function of rotational speed are presented.

  3. Comparative analysis of thrust production for distinct arm-pull styles in competitive swimming.

    Science.gov (United States)

    Loebbecke, Alfred von; Mittal, Rajat

    2012-07-01

    A computational fluid dynamics (CFD) based analysis of the propulsive forces generated by two distinct styles of arm-pulls in front-crawl as well as backstroke is presented in this Technical Brief. Realistic models of the arm pulling through water are created by combining underwater video footage and laser-scans of an arm with computer animation. The contributions of drag and lift forces on the arm to thrust are computed from CFD, and it is found that lift forces provide a dominant contribution to thrust for all the arm-pull styles examined. However, contrary to accepted notions in swimming, pronounced sculling (lateral motion) not only does not increase the contribution of lift forces on the hand to overall thrust, it decreases the contribution of drag forces to thrust. Consequently, pronounced sculling seems to reduce the effectiveness of the arm-pull.

  4. Influence of Structural Parameters on the Performance of Vortex Valve Variable-Thrust Solid Rocket Motor

    Science.gov (United States)

    Wei, Xianggeng; Li, Jiang; He, Guoqiang

    2017-04-01

    The vortex valve solid variable thrust motor is a new solid motor which can achieve Vehicle system trajectory optimization and motor energy management. Numerical calculation was performed to investigate the influence of vortex chamber diameter, vortex chamber shape, and vortex chamber height of the vortex valve solid variable thrust motor on modulation performance. The test results verified that the calculation results are consistent with laboratory results with a maximum error of 9.5%. The research drew the following major conclusions: the optimal modulation performance was achieved in a cylindrical vortex chamber, increasing the vortex chamber diameter improved the modulation performance of the vortex valve solid variable thrust motor, optimal modulation performance could be achieved when the height of the vortex chamber is half of the vortex chamber outlet diameter, and the hot gas control flow could result in an enhancement of modulation performance. The results can provide the basis for establishing the design method of the vortex valve solid variable thrust motor.

  5. Thrust ripple optimization and experiment for a permanent magnet linear synchronous motor

    Institute of Scientific and Technical Information of China (English)

    XU Yue-tong; FU Jian-zhong; CHEN Zi-chen

    2006-01-01

    Thrust ripple such as end force,slot force and normal force are key factors that affect the properties of permanent magnet linear synchronous motors (PMLSM).According to different mechanics and analytical models,end force resulting from open magnetic circuit of PMLSM was greatly decreased by optimizing the length of the PMLSM mover.Slot force caused by slot effect was greatly reduced by using fraction slot structure,and normal force was calculated through the finite element method (FEM).After thrust ripple was calculated,its uniform formula was obtained through Fourier series nonlinear regression.An experimental system was set up to measure thrust ripple,and experiment results demonstrated that experimental force ripple was quite in line with that calculated by the fitting formula.The optimal theory and analysis method is effective,and the obtained formula can be utilized to compensate thrust ripple in practical applications and improve the motion performance of PMLSM.

  6. Potential applications of skip SMV with thrust engine

    Science.gov (United States)

    Wang, Weilin; Savvaris, Al

    2016-11-01

    This paper investigates the potential applications of Space Maneuver Vehicles (SMV) with skip trajectory. Due to soaring space operations over the past decades, the risk of space debris has considerably increased such as collision risks with space asset, human property on ground and even aviation. Many active debris removal methods have been investigated and in this paper, a debris remediation method is first proposed based on skip SMV. The key point is to perform controlled re-entry. These vehicles are expected to achieve a trans-atmospheric maneuver with thrust engine. If debris is released at altitude below 80 km, debris could be captured by the atmosphere drag force and re-entry interface prediction accuracy is improved. Moreover if the debris is released in a cargo at a much lower altitude, this technique protects high value space asset from break up by the atmosphere and improves landing accuracy. To demonstrate the feasibility of this concept, the present paper presents the simulation results for two specific mission profiles: (1) descent to predetermined altitude; (2) descent to predetermined point (altitude, longitude and latitude). The evolutionary collocation method is adopted for skip trajectory optimization due to its global optimality and high-accuracy. This method is actually a two-step optimization approach based on the heuristic algorithm and the collocation method. The optimal-control problem is transformed into a nonlinear programming problem (NLP) which can be efficiently and accurately solved by the sequential quadratic programming (SQP) procedure. However, such a method is sensitive to initial values. To reduce the sensitivity problem, genetic algorithm (GA) is adopted to refine the grids and provide near optimum initial values. By comparing the simulation data from different scenarios, it is found that skip SMV is feasible in active debris removal and the evolutionary collocation method gives a truthful re-entry trajectory that satisfies the

  7. Thrust Enhancement in Hypervelocity Nozzles by Chemical Catalysis

    Science.gov (United States)

    Singh, D. J.; Carpenter, Mark H.; Drummond, J. P.

    1997-01-01

    In the hypersonic flight regime, the air-breathing supersonic combustion ramjet (scramjet) has been shown to be a viable propulsion system. The current designs of scramjet engines provide performance benefits only up to a Mach number of 14. Performance losses increase rapidly as the Mach number increases. To extend the applicability of scram'jets beyond Mach 14, research is being conducted in the area of inlet and wave drag reduction, skin-friction and heat-transfer reduction, nozzle loss minimization, low-loss mixing, and combustion enhancement. For high Mach number applications, hydrogen is the obvious fuel choice because of its high energy content per unit mass in comparison with conventional fuels. These flight conditions require engines to operate at supersonic internal velocities, high combustor temperatures, and low static pressures. The high static temperature condition enhances the production of radicals such as H and OH, and the low-pressure condition slows the reaction rates, particularly the recombination reactions. High-temperature and low-pressure constraints, in combination with a small residence time, result in a radical-rich exhaust gas mixture exiting the combustor. At high Mach number conditions (due to low residence time), H and OH do not have enough time to recombine ; thus, a significant amount of energy is lost as these high-energy free radical are exhausted. The objective of the present study is to conduct a flowfield analysis for a typical nozzle geometry for NASP-type vehicle to assess for thrust enhancement in hypervelocity nozzles by substituting small amount of phosphine for hydrogen.

  8. Back-thrusting in Lesser Himalaya: Evidences from magnetic fabric studies in parts of Almora crystalline zone, Kumaun Lesser Himalaya

    Indian Academy of Sciences (India)

    Amar Agarwal; K K K K Agarwal; R Bali; Chandra Prakash; Gaurav Joshi

    2016-06-01

    The present study aims to understand evolution of the Lesser Himalaya, which consists of (meta) sedimentaryand crystalline rocks. Field studies, microscopic and rock magnetic investigations have beencarried out on the rocks near the South Almora Thrust (SAT) and the North Almora Thrust (NAT),which separates the Almora Crystalline Zone (ACZ) from the Lesser Himalayan sequences (LHS). Theresults show that along the South Almora Thrust, the deformation is persistent; however, near theNAT deformation pattern is complex and implies overprinting of original shear sense by a youngerdeformational event. We attribute this overprinting to late stage back-thrusting along NAT, active afterthe emplacement of ACZ. During this late stage back-thrusting, rocks of the ACZ and LHS were coupled.Back-thrusts originated below the Lesser Himalayan rocks, probably from the Main Boundary Thrust,and propagated across the sedimentary and crystalline rocks. This study provides new results frommultiple investigations, and enhances our understanding of the evolution of the ACZ.

  9. A Review of High Thrust, High Delta-V Options for Microsatellite Missions

    Science.gov (United States)

    2009-06-25

    millinewtons of thrust. Pushing the limits of microsatellite capability is the Hall thruster design of Berti, et al.23 and Biagioni , et al.,24...of thrust with an Isp greater than 1000 s. Biagioni , et al. further specify that their thruster weighs 0.6 kg and that the power and flow control...Sept. 2002, AIAA-2002-5714. 23Berti, M., Biagioni , L., Cesari, U., Saverdi, M., and Andrenucci, M., “Development and Preliminary Characterization of a

  10. Static performance investigation of a skewed-throat multiaxis thrust-vectoring nozzle concept

    Science.gov (United States)

    Wing, David J.

    1994-01-01

    The static performance of a jet exhaust nozzle which achieves multiaxis thrust vectoring by physically skewing the geometric throat has been characterized in the static test facility of the 16-Foot Transonic Tunnel at NASA Langley Research Center. The nozzle has an asymmetric internal geometry defined by four surfaces: a convergent-divergent upper surface with its ridge perpendicular to the nozzle centerline, a convergent-divergent lower surface with its ridge skewed relative to the nozzle centerline, an outwardly deflected sidewall, and a straight sidewall. The primary goal of the concept is to provide efficient yaw thrust vectoring by forcing the sonic plane (nozzle throat) to form at a yaw angle defined by the skewed ridge of the lower surface contour. A secondary goal is to provide multiaxis thrust vectoring by combining the skewed-throat yaw-vectoring concept with upper and lower pitch flap deflections. The geometric parameters varied in this investigation included lower surface ridge skew angle, nozzle expansion ratio (divergence angle), aspect ratio, pitch flap deflection angle, and sidewall deflection angle. Nozzle pressure ratio was varied from 2 to a high of 11.5 for some configurations. The results of the investigation indicate that efficient, substantial multiaxis thrust vectoring was achieved by the skewed-throat nozzle concept. However, certain control surface deflections destabilized the internal flow field, which resulted in substantial shifts in the position and orientation of the sonic plane and had an adverse effect on thrust-vectoring and weight flow characteristics. By increasing the expansion ratio, the location of the sonic plane was stabilized. The asymmetric design resulted in interdependent pitch and yaw thrust vectoring as well as nonzero thrust-vector angles with undeflected control surfaces. By skewing the ridges of both the upper and lower surface contours, the interdependency between pitch and yaw thrust vectoring may be eliminated

  11. Association of varus thrust with prevalent patellofemoral osteoarthritis: A cross-sectional study.

    Science.gov (United States)

    Iijima, Hirotaka; Fukutani, Naoto; Yamamoto, Yuko; Hiraoka, Masakazu; Miyanobu, Kazuyuki; Jinnouchi, Masashi; Kaneda, Eishi; Isho, Takuya; Aoyama, Tomoki; Kuroki, Hiroshi; Matsuda, Shuichi

    2017-08-31

    This cross-sectional study investigated (i) the association of varus thrust during gait with the presence of patellofemoral osteoarthritis (PFOA) in patients with medial knee osteoarthritis (OA) and (ii) patellar alignment in the knees with varus thrust. Participants from orthopedic clinics (n=171; mean age, 73.4 years; 71.9% female) diagnosed with radiographic medial knee OA (Kellgren/Lawrence [K/L] grade ≥1) were included in this study, and underwent gait observation for varus thrust assessment using 2D video analysis. A radiographic skyline view was used to assess the presence of medial PFOA using the grading system from the Osteoarthritis Research Society International Atlas. The tibiofemoral joint K/L grade, patellar alignment (i.e., lateral shift and tilting angle), and knee pain intensity were also evaluated as covariates. Thirty-two (18.7%) of 171 patients exhibited varus thrust and they presented significantly higher knee pain (46.0±3.04mm vs. 32.4±2.73mm; P=0.024), a lower patellar tilting angle (P=0.024), and a higher prevalence of PFOA compared with those without varus thrust. A logistic regression analysis with adjustment of covariates showed that varus thrust was significantly associated with higher odds of the presence of mixed and medial PFOA, and trended to significantly associate with any PFOA, including lateral PFOA. This indicates that varus thrust was associated with PFOA in a compartment-nonspecific manner in patients with medial knee OA. Varus thrust may represent a clinical disease feature of more advanced and multicompartmental disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Contemporary tectonics of the Himalayan frontal fault system: folds, blind thrusts and the 1905 Kangra earthquake

    Science.gov (United States)

    Yeats, Robert S.; Lillie, Robert J.

    The Sub-Himalayan fold-thrust belt consists of deformed late Cenozoic and older deposits south of the Main Boundary thrust (MBT). In Pakistan, east of the Indus River, the Sub-Himalaya comprises the Potwar Plateau and the Salt Range, which is thrust southward over the Jhelum River floodplain along the Salt Range thrust. Although an estimated 9-14 mm a -1 shortening has been taken up on the Salt Range thrust during the last 2 Ma, the range-front scarp does not show signs of recent faulting. Shortening may be shifting southward to the Lilla overpressured anticline, which rises from the Jhelum floodplain as a fault-propagation fold. Farther east, shortening is partitioned among several anticlines underlain by foreland- and hinterland-dipping blind thrusts. Southeast of the main deformation zone, the Pabbi Hills overpressured anticline is best explained as a fault-propagation fold. Throughout the Potwar Plateau and Salt Range, thrusts and folds rise from a basal décollement horizon in Eocambrian evaporites. The Pakistani part of the décollement horizon could generate large earthquakes only if these evaporites die out northward at seismogenic depths. In India and Nepal, the Sub-Himalaya is narrower, reflecting the absence of evaporites and a steeper slope of the basement towards the hinterland. The southern boundary of the Sub-Himalaya is the Himalayan Front fault, discontinuous because part of the shortening is expressed at the surface by folding. Broad, alluvial synclinal valleys (dun valleys) are bounded on the south by rising barrier anticlines of Siwalik molasse. The 1905 Kangra earthquake (M8) produced uplift on the Mohand anticline and the Dehra Dun Valley, suggesting that this earthquake occurred on a décollement horizon above basement, downdip from the fold. If so, the Kangra event is the largest known earthquake on a blind thrust expressed at the surface as a fold.

  13. Alongstrike geometry variations of the Carpathian thrust front east of Tarnów (SE Poland) as intersection phenomenon related to thrust-floor palaeotopography

    Science.gov (United States)

    Gluszynski, Andrzej; Aleksandrowski, Pawel

    2017-04-01

    Structural geometry of the Miocene (Badenian-Sarmatian) Carpathian orogenic front between Tarnów and Pilzno was investigated, using borehole and 2D and 3D seismic data. In line with some earlier studies by other authors, but in much more comprehensive way, our study reveals details of the alongstrike changing structural geometry of the Carpathian orogenic front and offers a model of its tectonic evolution. At places the frontal thrust of the Carpathians is blind and accompanied by well developed wedge tectonics phenomena. Elsewhere it is emergent at the surface and shows an apparently simple structure. The base of the fold-thrust zone rests on a substratum with highly variable palaeotopography, which includes a major palaeovalley incised in the Mesozoic basement to a depth exceeding 1 km. The palaeovalley floor was covered with salt-bearing evaporites at the time when the thrusting took place. The wedge tectonics phenomena include backthrusts and a prominent crocodile structure. The tectonic wedge is formed by stacked thrust-slices of the Cretaceous-to-Oligocene flysch of the Skole nappe. This wedge has forced a basal Miocene evaporitic layer (including salt) to split into two horizons (1) the lower one, which acted as a tectonic lubricant along the floor thrust of the forward-moving flysch wedge, and (2) the upper one, along which the Miocene sediments of the Carpathian foredeep were underthrusted by the flysch wedge. This resulting crocodile structure has the flysch wedge in its core, a passive roof of Miocene sediments at the top and tilted Miocene strata at its front, defining a frontal homocline. A minor triangle zone, cored with deformed evaporites, has formed due to backthrust branching at the rear of the frontal monocline. At other places, the Carpathian flysch and its basal thrust, emerge at the surface. The flysch must have once also formed a wedge there, but was mostly removed by erosion following its elevation above the present-day topographic surface

  14. Fault Characteristics in Longmen Mountain Thrust Belt,Western Sichuan Foreland Basin,China

    Institute of Scientific and Technical Information of China (English)

    Wan Guimei; Tang Liangjie; Yang Keming; Jin Wenzheng; LU Zhizhou; Yu Yixin

    2008-01-01

    Through field geological survey,the authors found that abundant thrust faults developed in the Longmen (龙门) Mountain thrust belt.These faults can be divided into thrust faults and strike-slip faults according to their formation mechanisms and characteristics.Furthermore,these faults can be graded into primary fault,secondary fault,third-level fault,and fourth-level fault according to their scale and role in the tectonic evolution of Longmen Mountain thrust belt.Each thrust fault is composed of several secondary faults,such as Qingchuan (青川)-Maowen (茂汶) fault zone is composed of Qiaozhuang (乔庄) fault,Qingxi (青溪) fault,Maowen fault,Ganyanggou (赶羊沟) fault,etc..The Longmen Mountain thrust belt experienced early Indosinian movement,Anxian (安县) movement,Yanshan (燕山)movement,and Himalayan movement,and the faults formed gradually from north to south.

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

    Science.gov (United States)

    Deere, Karen A.; Berrier, Bobby L.; Flamm, Jeffrey D.; Johnson, Stuart K.

    2005-01-01

    A computational investigation of a two-dimensional nozzle was completed to assess the use of fluidic injection to manipulate flow separation and cause thrust vectoring of the primary jet thrust. The nozzle was designed with a recessed cavity to enhance the throat shifting method of fluidic thrust vectoring. Several design cycles with the structured-grid, computational fluid dynamics code PAB3D and with experiments in the NASA Langley Research Center Jet Exit Test Facility have been completed to guide the nozzle design and analyze performance. This paper presents computational results on potential design improvements for best experimental configuration tested to date. Nozzle design variables included cavity divergence angle, cavity convergence angle and upstream throat height. Pulsed fluidic injection was also investigated for its ability to decrease mass flow requirements. Internal nozzle performance (wind-off conditions) and thrust vector angles were computed for several configurations over a range of nozzle pressure ratios from 2 to 7, with the fluidic injection flow rate equal to 3 percent of the primary flow rate. Computational results indicate that increasing cavity divergence angle beyond 10 is detrimental to thrust vectoring efficiency, while increasing cavity convergence angle from 20 to 30 improves thrust vectoring efficiency at nozzle pressure ratios greater than 2, albeit at the expense of discharge coefficient. Pulsed injection was no more efficient than steady injection for the Dual Throat Nozzle concept.

  16. Deformation in thrust-ramp anticlines and duplexes: implications for geometry and porosity

    Energy Technology Data Exchange (ETDEWEB)

    Groshong, R.H. Jr.; Usdansky, S.I.

    1986-05-01

    A computerized kinematic model of thrust-ramp anticline geometry allows workers to predict the zones of greatest deformation in ramp anticlines and fault duplexes. The model assumes a constant cross-section area, symmetrical fold hinges, and slip in the hanging wall parallel to the ramp and forelimb. Assuming that the collapse of original porosity or the generation of secondary fracture porosity is proportional to deformation, the model can be used to predict porosity changes. Deformation in a single ramp anticline is greatest in the forelimb and backlimb, and may be absent in the crest. A duplex structure results from comparatively closely spaced thrusts that have a common upper detachment horizon. Relatively wide spacing between the duplex faults yields a bumpy roofed duplex as in the central Appalachians. Forelimbs may be deformed twice and should show greater porosity modification. Relatively close spacing between ramp-and-flat thrusts can produce a listric-fault, snakehead anticline geometry because younger faults deform the preexisting thrust slices. The resulting geometry is here called a snakehead duplex and appears to be fairly common, as in the Jumpingpound field in the Canadian Rockies. Each thrust slice within the duplex is deformed six times or more, providing the maximum opportunity for deformation-related porosity changes. Maximum fracture porosity should occur in thrusts having listric-fan or snakehead duplex geometry. Structures involving duplexes generally should be better than isolated ramp anticlines.

  17. Seismic reflection profiles from offshore central California: evidence for post-Miocene imbricate thrust faulting

    Energy Technology Data Exchange (ETDEWEB)

    Crouch, J.K.; Bachman, S.

    1984-04-01

    High-resolution, 36-fold seismic reflection data with penetration to 3 sec have been collected recently in the northeastern offshore Santa Maria basin, the northern Santa Barbara Channel, and off Point Conception, California. These profiles reveal major east-over-west thrust in areas previously interpreted as being characterized by strike-slip faults and/or high-angle normal or reverse faults. Like those in well known foreland thrust belts, these faults typically from an imbricate system in which they curve asymptotically downward to a common basal sole thrust. ''Soling out'' generally occurs at depths of 1.5-3km (5000-10,000 ft). Detailed mapping of faults and folds associated with these thrust systems coupled with fault-plane solutions suggest that: these thrust formed within the last 5 m.y.,; many have modern activity; and compressive forces causing them are normal to the strike of the San Andreas fault. These observations agree with present-day plate motion studies which require that Pacific-North American relative plate motion include a component of compression orthogonal to the San Andreas fault. These overthrust regions are all sites of recent major petroleum discoveries. However, these discoveries have all been made on obvious anticlinal structures that generally are attributed to wrench tectonics. Recognition of thrust faulting in these areas may lead to additional discoveries from more subtle geologic traps associated with overthrusting.

  18. Thrust joint manipulation utilization by U.S. physical therapists.

    Science.gov (United States)

    Puentedura, Emilio J; Slaughter, Rebecca; Reilly, Sean; Ventura, Erwin; Young, Daniel

    2017-05-01

    Online survey study. To determine physical therapists' utilization of thrust joint manipulation (TJM) and their comfort level in using TJM between the cervical, thoracic, and lumbar regions of the spine. We hypothesized that physical therapists who use TJM would report regular use and comfort providing it to the thoracic and lumbar spines, but not so much for the cervical spine. Recent surveys of first professional physical therapy degree programs have found that TJM to the cervical spine is not taught to the same degree as to the thoracic and lumbar spines. We developed a survey to capture the required information and had a Delphi panel of 15 expert orthopedic physical therapists review it and provide constructive feedback. A revised version of the survey was sent to the same Delphi panel and consensus was obtained on the final survey instrument. The revised survey was made available to any licensed physical therapists in the U.S.A. using an online survey system, from October 2014 through June 2015. Of 1014 responses collected, 1000 completed surveys were included for analysis. There were 478 (48%) males; the mean age of respondents was 39.7 ± 10.81 years (range 24-92); and mean years of clinical experience was 13.6 ± 10.62. A majority of respondents felt that TJM was safe and effective when applied to lumbar (90.5%) and thoracic (91.1%) spines; however, a smaller percentage (68.9%) felt that about the cervical spine. More therapists reported they would perform additional screening prior to providing TJM to the cervical spine than they would for the lumbar and thoracic spines. Therapists agreed they were less likely to provide and feel comfortable with TJM in the cervical spine compared to the thoracic and lumbar spines. Finally, therapists who are male; practice in orthopedic spine setting; are aware of manipulation clinical prediction rules; and have manual therapy certification, are more likely to use TJM and be comfortable with it in all three regions

  19. Performance characteristics of two multiaxis thrust-vectoring nozzles at Mach numbers up to 1.28

    Science.gov (United States)

    Wing, David J.; Capone, Francis J.

    1993-01-01

    The thrust-vectoring axisymmetric (VA) nozzle and a spherical convergent flap (SCF) thrust-vectoring nozzle were tested along with a baseline nonvectoring axisymmetric (NVA) nozzle in the Langley 16-Foot Transonic Tunnel at Mach numbers from 0 to 1.28 and nozzle pressure ratios from 1 to 8. Test parameters included geometric yaw vector angle and unvectored divergent flap length. No pitch vectoring was studied. Nozzle drag, thrust minus drag, yaw thrust vector angle, discharge coefficient, and static thrust performance were measured and analyzed, as well as external static pressure distributions. The NVA nozzle and the VA nozzle displayed higher static thrust performance than the SCF nozzle throughout the nozzle pressure ratio (NPR) range tested. The NVA nozzle had higher overall thrust minus drag than the other nozzles throughout the NPR and Mach number ranges tested. The SCF nozzle had the lowest jet-on nozzle drag of the three nozzles throughout the test conditions. The SCF nozzle provided yaw thrust angles that were equal to the geometric angle and constant with NPR. The VA nozzle achieved yaw thrust vector angles that were significantly higher than the geometric angle but not constant with NPR. Nozzle drag generally increased with increases in thrust vectoring for all the nozzles tested.

  20. Study of thrust and nappe tectonics in the eastern Jiaodong Peninsula, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG HongYuan; HOU QuanLin; CAO DaiYong

    2007-01-01

    Thrust and nappe tectonics have affected the eastern Jiaodong Peninsula, the easternmost terminal of the Sulu Ultra-high Pressure Metamorphic Belt. Four nappes have been mapped, named respectively the Shidao, Rongcheng, Mishan and Mouping nappes. The methods used included multi-scale structural analysis and structural chronology analysis. These nappes define four deep level slip-thrust shear zones that were mainly active in the Mesozoic. The amount of ductile deformation decreases from the Shidao to Rongcheng to Mouping to Mishan shear zones, and shows an inverse relationship with temperature. 40Ar/39Ar chronological analysis and the chronological results of former workers reveal four movement steps defined by the development of thrusts and nappes in the late Triassic (210-180 Ma), extensional movement from the Jurassic to early Cretaceous (180-130 Ma), slip-thrust movement in the Early Cretaceous (130-120 Ma), and extensional movement since the Late Cretaceous (120 Ma). The order of boundary shear zone motion in the period of slip-thrust movement during the Early Cretaceous (130-120 Ma) was along the Shidao, Rongcheng, Mouping and finally the Mishan shear zone. This resulted in clockwise rotation of the nappes relative to block west to the Tan-Lu Faults. Because of the similar evolutionary history of the Tan-Lu Faults and the thrust and nappe structure in the eastern Jiaodong Peninsula, slip dislocation along the Tan-Lu Faults might have been absorbed by thrust and nappe tectonics in the Jiaodong area in the Mesozoic era, resulting in much less dislocation on the Tan-Lu faults in North Eastern China than that in south along the Jiaodong Peninsula.

  1. Study of thrust and nappe tectonics in the eastern Jiaodong Peninsula, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Thrust and nappe tectonics have affected the eastern Jiaodong Peninsula, the easternmost terminal of the Sulu Ultra-high Pressure Metamorphic Belt. Four nappes have been mapped, named respectively the Shidao, Rongcheng, Mishan and Mouping nappes. The methods used included multi-scale struc- tural analysis and structural chronology analysis. These nappes define four deep level slip-thrust shear zones that were mainly active in the Mesozoic. The amount of ductile deformation decreases from the Shidao to Rongcheng to Mouping to Mishan shear zones, and shows an inverse relationship with temperature. 40Ar/39Ar chronological analysis and the chronological results of former workers reveal four movement steps defined by the development of thrusts and nappes in the late Triassic (210-180 Ma), extensional movement from the Jurassic to early Cretaceous (180-130 Ma), slip-thrust movement in the Early Cretaceous (130-120 Ma), and extensional movement since the Late Cretaceous (120 Ma). The order of boundary shear zone motion in the period of slip-thrust movement during the Early Cre- taceous (130-120 Ma) was along the Shidao, Rongcheng, Mouping and finally the Mishan shear zone. This resulted in clockwise rotation of the nappes relative to block west to the Tan-Lu Faults. Because of the similar evolutionary history of the Tan-Lu Faults and the thrust and nappe structure in the eastern Jiaodong Peninsula, slip dislocation along the Tan-Lu Faults might have been absorbed by thrust and nappe tectonics in the Jiaodong area in the Mesozoic era, resulting in much less dislocation on the Tan-Lu faults in North Eastern China than that in south along the Jiaodong Peninsula.

  2. Associations of varus thrust and alignment with pain in knee osteoarthritis.

    Science.gov (United States)

    Lo, Grace H; Harvey, William F; McAlindon, Timothy E

    2012-07-01

    To investigate associations of varus thrust and varus static alignment with pain in patients with knee osteoarthritis (OA). This was a cross-sectional study of participants from a randomized controlled trial of vitamin D treatment for knee OA. Participants were video recorded while walking and scored for presence of varus thrust. Static alignment was measured on standard posteroanterior knee radiographs. Pain questions from the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire were used to assess symptoms. We calculated means for total WOMAC pain in relation to varus thrust and static varus alignment (i.e., corrected anatomic alignmentthrust and varus alignment as the predictors. There were 82 participants, 60% of whom were female. The mean±SD age was 65.1±8.5 years, and the mean±SD body mass index was 30.2±5.4 kg/m2. The mean total WOMAC pain score was 6.3 versus 3.9, respectively, in those with versus without definite varus thrust (P=0.007) and 5.0 versus 4.2 in those with versus without varus alignment (P=0.36). Odds ratios for pain with walking and standing were 4.7 (95% confidence interval 1.8-11.9) and 5.5 (95% confidence interval 2.2-14.2), respectively, in those with and those without definite varus thrust. There were no significant associations between varus alignment and responses to individual WOMAC pain questions. Sensitivity analyses suggested that varus classified using a more stringent definition might have been associated with pain on walking and standing. In patients with knee OA, varus thrust, and possibly varus static alignment, were associated with pain, specifically during weight-bearing activities. Treatment of varus thrust (e.g., via bracing or gait modification) may lead to improvement of symptoms. Copyright © 2012 by the American College of Rheumatology.

  3. Growth of the Zagros Fold-Thrust Belt and Foreland Basin, Northern Iraq, Kurdistan

    Science.gov (United States)

    Koshnaw, Renas; Horton, Brian; Stockli, Daniel; Barber, Douglas; Ghalib, Hafidh; Dara, Rebwar

    2016-04-01

    The Zagros orogenic belt in the Middle Eastern segment of the Alpine-Himalayan system is among the youngest seismically active continental collision zones on Earth. However, due to diachronous and incremental collision, the precise ages and kinematics of shortening and deposition remain poorly understood. The Kurdistan region of the Zagros fold-thrust belt and foreland basin contains well-preserved Neogene wedge-top and foredeep deposits that include clastic nonmarine fill of the Upper Fars, Lower Bakhtiari, and Upper Bakhtiari Formations. These deposits record significant information about orogenic growth, fold-thrust dynamics, and advance of the deformation front. Thermochronologic and geochronologic data from thrust sheets and stratigraphic archives combined with local earthquake data provide a unique opportunity to address the linkages between surface and subsurface geologic relationships. This research seeks to constrain the timing and geometry of exhumation and deformation by addressing two key questions: (1) Did the northwestern Zagros fold-thrust belt evolve from initial thin-skinned shortening to later thick-skinned deformation or vice-versa? (2) Did the fold-thrust belt advance steadily under critical/supercritical wedge conditions involving in-sequence thrusting or propagate intermittently under subcritical conditions with out-of-sequence deformation? From north to south, apatite (U-Th)/He ages from the Main Zagros Thrust, the Mountain Front Flexure (MFF), and additional frontal thrusts suggest rapid exhumation by ~10 Ma, ~5 Ma, and ~8 Ma respectively. Field observations and seismic sections indicate progressive tilting and development of growth strata within the Lower Bakhtiari Formation adjacent to the frontal thrusts and within the Upper Bakhtiari Formation near the MFF. In the Kurdistan region of Iraq, a regional balanced cross section constrained by new thermochronometric results, proprietary seismic reflection profiles, and earthquake hypocenters

  4. A workflow for 3D model building in fold-thrust belts

    Science.gov (United States)

    Watkins, Hannah; Bond, Clare; Butler, Rob

    2016-04-01

    3D geological models can be used in fold-thrust belts for many purposes such as analysing geometric variation in folds, kinematic modelling to restore fold surfaces, generating strain distribution maps and predicting fracture network distribution. We present a workflow for 3D model building using outcrop bedding data, geological maps, Digital Terrain Models (DTM's), air photos and field photographs. We discuss the challenges of software limitations for 3D kinematic restoration and forward modelling in fold-thrust belt settings. We then discuss the sensitivity of model building approaches to the application of 3D geological models in fold-thrust belts for further analysis e.g. changes in along strike fold geometry, restoration using kinematic and geomechanical modelling, strain prediction and Discrete Fracture Network (DFN) modelling. To create 3D models geological maps and bedding data are digitised using Move software; digitised maps and data are then draped onto DTM's. A series of closely spaced cross section lines are selected; the orientation of these is calculated by determining the average orientation of bedding dip direction. Fault and horizon line intersections, along with bedding data from within a narrow margin of the section lines are projected onto each cross section. Field photographs and sketches are integrated into the cross sections to determine thrust angles at the surface. Horizon lines are then constructed using bedding data. Displacement profiles for thrusts are plotted to ensure thrust displacements are valid with respect to neighbouring cross section interpretations; any discrepancies are alleviated by making minor adjustments to horizon and thrust lines, while ensuring that resultant cross section geometries still adhere to bedding data and other field observations. Once the cross sections have been finalised, 3D surfaces are created using the horizon and thrust line interpretations on each cross section. The simple curvature of 3D surfaces

  5. Multiphysics Computational Analysis of a Solid-Core Nuclear Thermal Engine Thrust Chamber

    Science.gov (United States)

    Wang, Ten-See; Canabal, Francisco; Cheng, Gary; Chen, Yen-Sen

    2007-01-01

    The objective of this effort is to develop an efficient and accurate computational heat transfer methodology to predict thermal, fluid, and hydrogen environments for a hypothetical solid-core, nuclear thermal engine - the Small Engine. In addition, the effects of power profile and hydrogen conversion on heat transfer efficiency and thrust performance were also investigated. The computational methodology is based on an unstructured-grid, pressure-based, all speeds, chemically reacting, computational fluid dynamics platform, while formulations of conjugate heat transfer were implemented to describe the heat transfer from solid to hydrogen inside the solid-core reactor. The computational domain covers the entire thrust chamber so that the afore-mentioned heat transfer effects impact the thrust performance directly. The result shows that the computed core-exit gas temperature, specific impulse, and core pressure drop agree well with those of design data for the Small Engine. Finite-rate chemistry is very important in predicting the proper energy balance as naturally occurring hydrogen decomposition is endothermic. Locally strong hydrogen conversion associated with centralized power profile gives poor heat transfer efficiency and lower thrust performance. On the other hand, uniform hydrogen conversion associated with a more uniform radial power profile achieves higher heat transfer efficiency, and higher thrust performance.

  6. A kinematic model for the formation of duplex systems with a perfectly planar roof thrust

    Science.gov (United States)

    Contreras, Juan; Suter, Max

    1997-03-01

    We present a cross-sectional kinematic forward model for the formation of duplexes with a perfectly planar roof thrust. The major assumptions are a constant dip and constant spacing of the ramps in the undeformed state and sequential deformation in the direction of tectonic transport, with equal displacement along each ramp. The model is based on a coordinate transformation that simulates flexural slip parallel to the active fault surface. This causes angular parallel folds and keeps the layer thickness constant, except in the forelimbs of the horses. Attempts by previous workers to simulate the formation of duplexes with a perfectly planar roof thrust, on the other hand, were based on the assumptions of constant bed thickness and bed length, or a different topology of the axial planes delimiting the forelimbs of the horses, and resulted in corrugated roof thrusts. We show that it is not possible to form a flat roof duplex type and preserve the forelimb thickness of the horses under flexural slip parallel to the active fault. We describe duplexes by three parameters which are the separation s between ramps, the ramp length l, and the displacement u along the ramps. In a {u}/{s} vs {l}/{s} diagram, duplexes with a perfectly planar roof thrust, resulting from numerical experiments with our kinematic algorithm, occupy specific families of straight lines. Our results are independent of the dip or internal geometry of the thrust ramps.

  7. Exploring for hydrocarbons under thrust belts - A challenging new frontier in the Carpathians and elsewhere

    Energy Technology Data Exchange (ETDEWEB)

    Picha, F.J. [Chevron Overseas Petroleum, Inc., San Ramon, CA (United States)

    1996-10-01

    New significant reserves of hydrocarbons may occur in subthrust autochthonous and parautochthonous series buried below the frontal zones of thin-skinned thrust belts. The subthrust plays have been tested in several orogenic belts of the world, the Carpathians being one of the best examples. The arcuate thin-skinned Carpathian orogenic belt, which evolved during the Mesozoic and Cenozoic, is thrust tens of kilometers over its Neogene foredeeps and the underlying. European plate. Various structural and stratigraphic settings and potential hydrocarbon plays have been recognized within the buried margins of the European plate, including a late Paleozoic Hercynian compressional system, Mesozoic rifted margins of the Tethys, and a Cenozoic synorogenic foreland-type fault system. Possibly, deeper parautochthonous structures, documented on examples from the southern Apennines, may also be present below the thin-skinned frontal zone of the Carpathian thrust belt. In addition to these structural settings, large Paleogene valleys/submarine canyons have been found within the margins of the European plate. These structural and morphologic features, if combined with source rocks, reservoirs, and proper burial history, represent potential hydrocarbon plays. Generation of hydrocarbons from sources within the subthrust plate was greatly enhanced by emplacement of the wedge-shaped thrust belt, which may also provide a regional seal; therefore, the combination of the long and complex geological history of the European plate with the impact of the Alpine thrusting and foreland deformation created unique conditions for generation, entrapment, and preservation of hydrocarbons in subthrust settings.

  8. Engineering Research and Development and Technology thrust area report FY92

    Energy Technology Data Exchange (ETDEWEB)

    Langland, R.T.; Minichino, C. [eds.

    1993-03-01

    The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the technical staff and the technology needed to support current and future LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) to identify key technologies and (2) to conduct high-quality work to enhance our capabilities in these key technologies. To help focus our efforts, we identify technology thrust areas and select technical leaders for each area. The thrust areas are integrated engineering activities and, rather than being based on individual disciplines, they are staffed by personnel from Electronics Engineering, Mechanical Engineering, and other LLNL organizations, as appropriate. The thrust area leaders are expected to establish strong links to LLNL program leaders and to industry; to use outside and inside experts to review the quality and direction of the work; to use university contacts to supplement and complement their efforts; and to be certain that we are not duplicating the work of others. This annual report, organized by thrust area, describes activities conducted within the Program for the fiscal year 1992. Its intent is to provide timely summaries of objectives, theories, methods, and results. The nine thrust areas for this fiscal year are: Computational Electronics and Electromagnetics; Computational Mechanics; Diagnostics and Microelectronics; Emerging Technologies; Fabrication Technology; Materials Science and Engineering; Microwave and Pulsed Power; Nondestructive Evaluation; and Remote Sensing and Imaging, and Signal Engineering.

  9. How the bending kinematics of swimming lampreys build negative pressure fields for suction thrust.

    Science.gov (United States)

    Gemmell, Brad J; Fogerson, Stephanie M; Costello, John H; Morgan, Jennifer R; Dabiri, John O; Colin, Sean P

    2016-12-15

    Swimming animals commonly bend their bodies to generate thrust. For undulating animals such as eels and lampreys, their bodies bend in the form of waves that travel from head to tail. These kinematics accelerate the flow of adjacent fluids, which alters the pressure field in a manner that generates thrust. We used a comparative approach to evaluate the cause-and-effect relationships in this process by quantifying the hydrodynamic effects of body kinematics at the body-fluid interface of the lamprey, Petromyzon marinus, during steady-state swimming. We compared the kinematics and hydrodynamics of healthy control lampreys to lampreys whose spinal cord had been transected mid-body, resulting in passive kinematics along the posterior half of their body. Using high-speed particle image velocimetry (PIV) and a method for quantifying pressure fields, we detail how the active bending kinematics of the control lampreys were crucial for setting up strong negative pressure fields (relative to ambient fields) that generated high-thrust regions at the bends as they traveled all along the body. The passive kinematics of the transected lamprey were only able to generate significant thrust at the tail, relying on positive pressure fields. These different pressure and thrust scenarios are due to differences in how active versus passive body waves generated and controlled vorticity. This demonstrates why it is more effective for undulating lampreys to pull, rather than push, themselves through the fluid. © 2016. Published by The Company of Biologists Ltd.

  10. Traceable Calibration of the 3 axis Thrust Vector in the mN range

    Science.gov (United States)

    Hughes, B.; Oldfield, S.

    2004-10-01

    The possibility of measuring the three force components i.e. the main axial component and the two orthogonal radial components, generated by an electric propulsion system is important for two reasons. Firstly, to assess the impact of spacecraft/propulsion system integration issues, for example to verify the alignment of the thrust vector with the spacecraft centre-of-mass for spacecraft stability. Secondly, to operate the thruster properly during flight, for example to determine the thrust vector relative to the mechanical axis of the thruster. Furthermore, a three-axis measurement capability will be useful for the experimental performance verification of the next generation of vectored electric propulsion devices, especially regarding the many unresolved issues connected with indirect thrust measurement using electrostatic probes. The capability to monitor thrust vector drift in real time and with significant bandwidth is also important. Thus enabling vector drift during thruster warm-up, to be measured, and the response of vectored thrusters to change in vector demand can be assessed. In this paper we describe the design, construction and testing of an instrument proof of concept. The instrument was designed to accommodate a dummy thruster mass of 0.5 kg and operate in the 0 to 10 mN range. The directional resolution that has been demonstrated is better than 0.05 ° in both axes when operating at full thrust.

  11. CFD simulation of propeller and rudder performance when using additional thrust fins

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To analyse a possible way to improve the propulsion performance of ships, the unstructured grid and the Reynolds Average Navier-Stokes equations were used to calculate the performance of a propeller and rudder fitted with additional thrust fins in the viscous flow field.The computational fluid dynamics software FLUENT was used to simulate the thrust and torque coefficient as a function of the advance coefficient of propeller and the thrust efficiency of additional thrust fins.The pressure and velocity flow behind the propeller was calculated.The geometrical nodes of the propeller were constituted by FORTRAN program and the NUMBS method was used to create a configuration of the propeller, which was then used by GAMMBIT to generate the calculation model.The thrust efficiency of fins was calculated as a function of the number of additional fins and the attack angles.The results of the calculations agree fairly well with experimental data, which shows that the viscous flow solution we present is useful in simulating the performance of propellers and rudders with additional fins.

  12. Optimal low-thrust spiral trajectories using Lyapunov-based guidance

    Science.gov (United States)

    Yang, Da-lin; Xu, Bo; Zhang, Lei

    2016-09-01

    For an increasing number of electric propulsion systems used for real missions, it is very important to design optimal low-thrust spiral trajectories for these missions. However, it is particularly challenging to search for optimal low-thrust transfers. This paper describes an efficient optimal guidance scheme for the design of time-optimal and time-fixed fuel-optimal low-thrust spiral trajectories. The time-optimal solution is obtained with Lyapunov-based guidance, in which the artificial neural network (ANN) is adopted to implement control gains steering and the evolutionary algorithm is used as the learning algorithm for ANN. Moreover, the relative efficiency introduced in Q-law is analyzed and a periapis-and-apoapsis-centered burn structure is proposed for solving time-fixed fuel-optimal low-thrust orbit transfer problem. In this guidance scheme, the ANN is adopted to determine the burn structure within each orbital revolution and the optimal low-thrust orbit transfer problem is converted to the parameter optimization problem. This guidance scheme runs without an initial guess and provides closed form solutions. In addition, Earth J2 perturbation and Earth-shadow eclipse effects are considered in this paper. Finally, a comparison with solutions given by the literature demonstrates the effectiveness of the proposed method.

  13. Microstructures and strain variation: Evidence of multiple splays in the North Almora Thrust Zone, Kumaun Lesser Himalaya, Uttarakhand, India

    Science.gov (United States)

    Joshi, Gaurav; Agarwal, Amar; Agarwal, K. K.; Srivastava, Samriddhi; Alva Valdivia, L. M.

    2017-01-01

    The North Almora Thrust zone (NATZ) marks the boundary of the Almora Crystalline Complex (ACC) against the Lesser Himalayan Sedimentary sequence (LHS) in the north. Its southern counterpart, the South Almora Thrust (SAT), is a sharply marked contact between the ACC and the LHS in the south. Published studies argue various contradictory emplacement modes of the North Almora Thrust. Recent studies have implied splays of smaller back thrusts in the NATZ. The present study investigates meso- and microstructures, and strain distribution in the NATZ and compares it with strain distribution across the SAT. In the NATZ, field evidence reveals repeated sequence of 10-500 m thick slices of proto- to ultra-mylonite, thrust over the Lesser Himalayan Rautgara quartzite. In accordance with the field evidence, the strain analysis reveals effects of splays of smaller thrust in the NATZ. The study therefore, argues that contrary to popular nomenclature the northern contact of the ACC with the LHS is not a single thrust plane, but a thrust zone marked by numerous thrust splays.

  14. Aeroelastic response of an aircraft wing with mounted engine subjected to time-dependent thrust

    Science.gov (United States)

    Mazidi, A.; Kalantari, H.; Fazelzadeh, S. A.

    2013-05-01

    In this paper, the aeroelastic response of a wing containing an engine subjected to different types of time-dependent thrust excitations is presented. In order to precisely consider the spanwise and chordwise locations of the engine and the time-dependent follower force in governing equations, derived through Lagrange's method, the generalized function theory is used. Unsteady aerodynamic lift and moment in the time domain are considered in terms of Wagner's function. Numerical simulations of the aeroelastic response to different types of time-dependent thrust excitation and comparisons with the previously published results are supplied. Effects of the engine mass and location and also the type of time-dependent thrust on the wing aeroelastic response are studied and pertinent conclusions are outlined.

  15. Bubble mass center and fluid feedback force fluctuations activated by constant lateral impulse with variable thrust

    Science.gov (United States)

    Hung, R. J.; Long, Y. T.

    1995-01-01

    Sloshing dynamics within a partially filled rotating dewar of superfluid helium 2 are investigated in response to constant lateral impulse with variable thrust. The study, including how the rotating bubble of superfluid helium 2 reacts to the constant impulse with variable time period of thrust action in microgravity, how amplitudes of bubble mass center fluctuates with growth and decay of disturbances, and how fluid feedback forces fluctuates in activating on the rotating dewar through the dynamics of sloshing waves are investigated. The numerical computation of sloshing dynamics is based on the non-inertial frame spacecraft bound coordinate with lateral impulses actuating on the rotating dewar in both inertial and non-inertial frames of thrust. Results of the simulations are illustrated.

  16. Modifications of plasma density profile and thrust by neutral injection in a helicon plasma thruster

    Science.gov (United States)

    Takahashi, Kazunori; Takao, Yoshinori; Ando, Akira

    2016-11-01

    Argon propellant is introduced from the upstream and downstream sides of a high power helicon plasma thruster. The plasma density profile and the imparted thrust are measured for various upstream and downstream argon flow rates, where the total gas flow rate of 70 sccm and the resultant vacuum chamber pressure of 0.2 mTorr are maintained. It is observed that the imparted thrust increases with an increase in the downstream gas flow rate; simultaneously an upstream-peaking profile of the plasma density observed for the upstream gas injection becomes uniform for the downstream gas injection. The difference in the thrust between the upstream and downstream gas injections is enhanced by increasing the rf power. The observed density profiles are qualitatively consistent with theoretical predictions taking a neutral depletion effect into account.

  17. F-15B ACTIVE with thrust vectoring nozzles on test stand

    Science.gov (United States)

    1995-01-01

    This November 13, 1995, photograph of the F-15 Advanced Controls Technology for Integrated Vehicles (ACTIVE) at NASA's Dryden Flight Research Center, Edwards, California, shows the thrust stand being used for ground testing of a new thrust-vectoring concept involving two new Pratt & Whitney nozzles that can turn up to 20 degrees in any direction. These nozzles give the aircraft thrust control in the pitch (up and down) and yaw (left and right) directions. This will reduce drag and increase fuel economy or range as compared with conventional aerodynamic controls, which increase the retarding forces (drag) acting upon the aircraft. These tests could lead to significant performance increases for military and commercial aircraft. The research program is the product of a collaborative effort by NASA, the Air Force's Wright Laboratory, Pratt & Whitney, and McDonnell Douglas Aerospace.

  18. Experimental and theoretical comparison of the Probe Thrust Vector Control concept

    Science.gov (United States)

    Cavalleri, Robert; Tiarn, Weihnurng; Lewis, Lynn

    1991-01-01

    A concept that offers an alternate method for thrust vector control of liquid or solid propellant rockets is the use of a solid body or probe that is inserted on demand through the wall of the rocket nozzle. This Probe Thrust Vector Control (PTVC) concept is an alternative to that of a gimbaled nozzle or a Liquid Injection Thrust Vector control system. The viability of the PTVC concept can be assessed either experimentally and/or with the use of CFD. A purely experimental assessment is time consuming and expensive, whereas a CFD assessment is time- and cost-effective. Two key requirements of the concept are PTVC vectoring performance and active cooling requirements for the probe to maintain its thermal and structural integrity. The objective of the work reported here is presentation of experimental subscale cold flow tests and comparison of these tests with CFD predictions and the response time of the PTVC system.

  19. Investigation and Comparison Effects of Fluid Injection Type in Thrust Vector Control

    Directory of Open Access Journals (Sweden)

    M.R Heidari

    2016-01-01

    Full Text Available In this research, the effects of some liquid side injection from nozzle wall into exhaust gas of combustion chamber are studied. The side injection against main flow is as elliptical solid thing that change the symmetric of flow field on nozzle wall and causes some different pressure distribution on wall, and finally causes thrust vector deviation. Flows interaction causes some physical phenomena as bow shock wave in front of injection region. This paper explain the effects of this wave and variation velocity & pressure distribution at different cross sections of flow field and comparison results of air and other liquid fluid in thrust vector control system. The results are compared with experimental data and have well agreement with them. The results show that Freon is one of best injection liquid for this type of thrust vector control. Performance of Injection is optimum in relative position 35 to 40% nozzle divergence length.

  20. Nuclear-thermal rocket thrust transient effects on minimum-fuel lunar trajectories

    Science.gov (United States)

    Rivas, Matthew L.

    1995-01-01

    A technically viable option for low-cost minimum-fuel Lunar transfers with short trip times is the use of nuclear thermal rockets. However, little work has been done on the effects the associated thrust transients have on these optimal trajectories. The nominal thrust level of an engine is not immediately reached when the rocket is turned ``on.'' Similarly, when the engine is turned ``off'', the thrust and specific impulse levels decrease over a period of time which is directly related to both the flow effecs of the engine and cooling requirements. This paper presents an analysis of these effects on a typical optimal Lunar transfer. Several different models simulating the transient effects are used. They range from simple ``mass dumps'' to account for the extra required propellant to curve-fits of actual engine characteristics obtained from the NERVA nuclear rocket program.

  1. A computer program for wing subsonic aerodynamic performance estimates including attainable thrust and vortex lift effects

    Science.gov (United States)

    Carlson, H. W.; Walkley, K. B.

    1982-01-01

    Numerical methods incorporated into a computer program to provide estimates of the subsonic aerodynamic performance of twisted and cambered wings of arbitrary planform with attainable thrust and vortex lift considerations are described. The computational system is based on a linearized theory lifting surface solution which provides a spanwise distribution of theoretical leading edge thrust in addition to the surface distribution of perturbation velocities. The approach used relies on a solution by iteration. The method also features a superposition of independent solutions for a cambered and twisted wing and a flat wing of the same planform to provide, at little additional expense, results for a large number of angles of attack or lift coefficients. A previously developed method is employed to assess the portion of the theoretical thrust actually attainable and the portion that is felt as a vortex normal force.

  2. Gorringe Ridge gravity and magnetic anomalies are compatible with thrusting at a crustal scale

    Science.gov (United States)

    Galindo-Zaldívar, J.; Maldonado, A.; Schreider, A. A.

    2003-06-01

    The main features of the deep structure of the Gorringe Ridge are analysed on the basis of gravity and magnetic measurements, as well as seismic profiles, drill holes, rock dredges, submersible observations and seismicity data. The gravity and magnetic models of the Gettysburg and Ormonde seamounts, which form the Gorringe Ridge, suggest that the Moho is approximately flat and the upper part of the ridge corresponds to a northwestwards vergent fold. This structure is the result of a northwestward vergent thrust that deformed the oceanic crust, with a minimum slip of approximately 20 km. The activity of the thrust probably started 20 Myr, and produced the recent stages of seamount uplift. The seamount is mainly composed of gabbros of the oceanic crust, serpentinized rocks and alkaline basalts. The large antiform, located in the hangingwall of the thrust, is probably deformed by minor faults. This oceanic ridge is a consequence of the oblique convergence between the African Plate and the overlapping Eurasian Plate.

  3. Low-Thrust Orbital Transfers in the Two-Body Problem

    Directory of Open Access Journals (Sweden)

    A. A. Sukhanov

    2012-01-01

    Full Text Available Low-thrust transfers between given orbits within the two-body problem are considered; the thrust is assumed power limited. A simple method for obtaining the transfer trajectories based on the linearization of the motion near reference orbits is suggested. Required calculation accuracy can be reached by means of use of a proper number of the reference orbits. The method may be used in the case of a large number of the orbits around the attracting center; no averaging is necessary in this case. The suggested method also is applicable to the cases of partly given final orbit and if there are constraints on the thrust direction. The method gives an optimal solution to the linearized problem which is not optimal for the original nonlinear problem; the difference between the optimal solutions to the original and linearized problems is estimated using a numerical example. Also examples illustrating the method capacities are given.

  4. Optimal low-thrust trajectories for nuclear and solar electric propulsion

    Science.gov (United States)

    Genta, G.; Maffione, P. F.

    2016-01-01

    The optimization of the trajectory and of the thrust profile of a low-thrust interplanetary transfer is usually solved under the assumption that the specific mass of the power generator is constant. While this is reasonable in the case of nuclear electric propulsion, if solar electric propulsion is used the specific mass depends on the distance of the spacecraft from the Sun. In the present paper the optimization of the trajectory of the spacecraft and of the thrust profile is solved under the latter assumption, to obtain optimized interplanetary trajectories for solar electric spacecraft, also taking into account all phases of the journey, from low orbit about the starting planet to low orbit about the destination one. General plots linking together the travel time, the specific mass of the generator and the propellant consumption are obtained.

  5. Global Optimization of Low-Thrust Interplanetary Trajectories Subject to Operational Constraints

    Science.gov (United States)

    Englander, Jacob A.; Vavrina, Matthew A.; Hinckley, David

    2016-01-01

    Low-thrust interplanetary space missions are highly complex and there can be many locally optimal solutions. While several techniques exist to search for globally optimal solutions to low-thrust trajectory design problems, they are typically limited to unconstrained trajectories. The operational design community in turn has largely avoided using such techniques and has primarily focused on accurate constrained local optimization combined with grid searches and intuitive design processes at the expense of efficient exploration of the global design space. This work is an attempt to bridge the gap between the global optimization and operational design communities by presenting a mathematical framework for global optimization of low-thrust trajectories subject to complex constraints including the targeting of planetary landing sites, a solar range constraint to simplify the thermal design of the spacecraft, and a real-world multi-thruster electric propulsion system that must switch thrusters on and off as available power changes over the course of a mission.

  6. Thrust Reduction of Magnetic Levitation Vehicle Driven by Long Stator Linear Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Wan-Tsun Tseng

    2013-01-01

    Full Text Available The propulsion technology of long stator linear synchronous motors is used to drive high-speed maglev trains. The linear synchronous motor stator is divided into sections placed on guideway. The electric power supplies to stator sections in which the train just passes in change-step mode for long-distance operation. However, a thrust drop will be caused by change-step machinery for driving magnetic vehicle. According to the train speed and vehicle data, the change-step mode has three types of operation, namely premature commutation, simultaneous commutation, and late commutation. Each type of operation has a different thrust drop which can be affected by several parameters such as jerk, running speed, motor section length, and vehicle data. This paper focuses on determining the thrust drop of the change-step mode. The study results of this paper can be used to improve the operation system of high-speed maglev trains.

  7. Resistive thrust production can be as crucial as added mass mechanisms for inertial undulatory swimmers

    CERN Document Server

    Piñeirua, Miguel; Thiria, Benjamin

    2015-01-01

    In this paper, we address a crucial point regarding the description of moderate to high Reynolds numbers aquatic swimmers. For decades, swimming animals have been classified in two different families of propulsive mechanisms based on the Reynolds number: the "resistive" swimmers, using local friction to produce the necessary thrust force for locomotion at low Reynolds number and the "reactive" swimmers, lying in the high Reynolds range, and using added mass acceleration (described by perfect fluid theory). However, inertial swimmers are also systems that dissipate energy, due to their finite size, therefore involving strong resistive contributions, even for high Reynolds numbers. Using a complete model for the hydrodynamic forces, involving both reactive and resistive contributions, we revisit here the physical mechanisms responsible for the thrust production of such swimmers. We show, for instance, that the resistive part of the force balance is as crucial as added mass effects in the modeling of the thrust ...

  8. Feedback Optimal Control of Low-thrust Orbit Transfer in Central Gravity Field

    Directory of Open Access Journals (Sweden)

    Ashraf H. Owis

    2013-05-01

    Full Text Available Low-thrust trajectories with variable radial thrust is studied in this paper. The problem is tackled by solving the Hamilton- Jacobi-Bellman equation via State Dependent Riccati Equation( STDE technique devised for nonlinear systems. Instead of solving the two-point boundary value problem in which the classical optimal control is stated, this technique allows us to derive closed-loop solutions. The idea of the work consists in factorizing the original nonlinear dynamical system into a quasi-linear state dependent system of ordinary differential equations. The generating function technique is then applied to this new dynamical system, the feedback optimal control is solved. We circumvent in this way the problem of expanding the vector field and truncating higher-order terms because no remainders are lost in the undertaken approach. This technique can be applied to any planet-to-planet transfer; it has been applied here to the Earth-Mars low-thrust transfer

  9. Static internal performance including thrust vectoring and reversing of two-dimensional convergent-divergent nozzles

    Science.gov (United States)

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

    1984-01-01

    The effects of geometric design parameters on two dimensional convergent-divergent nozzles were investigated at nozzle pressure ratios up to 12 in the static test facility. Forward flight (dry and afterburning power settings), vectored-thrust (afterburning power setting), and reverse-thrust (dry power setting) nozzles were investigated. The nozzles had thrust vector angles from 0 deg to 20.26 deg, throat aspect ratios of 3.696 to 7.612, throat radii from sharp to 2.738 cm, expansion ratios from 1.089 to 1.797, and various sidewall lengths. The results indicate that unvectored two dimensional convergent-divergent nozzles have static internal performance comparable to axisymmetric nozzles with similar expansion ratios.

  10. Internal performance of two nozzles utilizing gimbal concepts for thrust vectoring

    Science.gov (United States)

    Berrier, Bobby L.; Taylor, John G.

    1990-01-01

    The internal performance of an axisymmetric convergent-divergent nozzle and a nonaxisymmetric convergent-divergent nozzle, both of which utilized a gimbal type mechanism for thrust vectoring was evaluated in the Static Test Facility of the Langley 16-Foot Transonic Tunnel. The nonaxisymmetric nozzle used the gimbal concept for yaw thrust vectoring only; pitch thrust vectoring was accomplished by simultaneous deflection of the upper and lower divergent flaps. The model geometric parameters investigated were pitch vector angle for the axisymmetric nozzle and pitch vector angle, yaw vector angle, nozzle throat aspect ratio, and nozzle expansion ratio for the nonaxisymmetric nozzle. All tests were conducted with no external flow, and nozzle pressure ratio was varied from 2.0 to approximately 12.0.

  11. Prediction and experimental measurement of the electromagnetic thrust generated by a microwave thruster system

    Institute of Scientific and Technical Information of China (English)

    Yang Juan; Wang Yu-Quan; Ma Yan-Jie; Li Peng-Fei; Yang Le; Wang Yang; He Guo-Qiang

    2013-01-01

    A microwave thruster system that can convert microwave power directly to thrust without a gas propellant is developed.In the system,a cylindrical tapered resonance cavity and a magnetron microwave source are used respectively as the thruster cavity and the energy source to generate the electromagnetic wave.The wave is radiated into and then reflected from the cavity to form a pure standing wave with non-uniform electromagnetic pressure distribution.Consequently,a net electromagnetic thrust exerted on the axis of the thruster cavity appears,which is demonstrated through theoretical calculation based on the electromagnetic theory.The net electromagnetic thrust is also experimentally measured in the range from 70 mN to 720 mN when the microwave output power is from 80 W to 2500 W.

  12. Recognition of Paleoearthquakes on the Puente Hills Blind Thrust Fault, California

    Science.gov (United States)

    Dolan, James F.; Christofferson, Shari A.; Shaw, John H.

    2003-04-01

    Borehole data from young sediments folded above the Puente Hills blind thrust fault beneath Los Angeles reveal that the folding extends to the surface as a discrete zone (-145 meters wide). Buried fold scarps within an upward- narrowing zone of deformation, which extends from the upward termination of the thrust ramp at 3 kilometers depth to the surface, document the occurrence of at least four large (moment-magnitude 7.2 to 7.5) earthquakes on this fault during the past 11,000 years. Future events of this type pose a seismic hazard to metropolitan Los Angeles. Moreover, the methods developed in this study can be used to refine seismic hazard assessments of blind thrusts in other metropolitan regions.

  13. Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

    Directory of Open Access Journals (Sweden)

    Jie Zhou

    2015-01-01

    Full Text Available With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP. Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt.

  14. Sandbox Experimental Study on the Influence of Rock Strength and Gravity on Formation of Thrusts

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A sandbox experiment model was designed to simulate how differences in rock strength and gravity between two blocks can influence the formation characteristics of thrusts. In the experiment the compression was from one direction with basement shortening and the initial surfaces of the model were oblique. The results show that if the initial surface was horizontal or the slope angle was smaller than 7°,the compression induced two groups of thrusts with opposite dip orientations. If the slope angle of the initial surface was greater than 7°, the compression induced only one group of thrusts with a dip orientation contrary to the original compression direction. This result is similar to the actual section of a collision zone between two continental blocks. By applying stress analysis, rock strength is shown to be an important factor in deformation. As other boundary conditions are changeless, it is the change of gravitational potential energy that leads to different deformation styles.

  15. Thrust and Torque Characteristics Based on a New cutter-head Load Model

    Institute of Scientific and Technical Information of China (English)

    LIU Jianqin; REN Jiabao; GUO Wei

    2015-01-01

    Full face rock tunnel boring machine(TBM) has been widely used in hard rock tunnels, however, there are few published theory about cutter-head design, and the design criteria of cutter-head under complex geological is not clear yet. To deal with the complex relationship among geological parameters, cutter parameters, and operating parameters during tunneling processes, a cutter-head load model is established by using CSM(Colorado school of mines) prediction model. Force distribution on cutter-head under a certain geology is calculated with the new established load model, and result shows that inner cutters bear more force than outer cutters, combining with disc cutters abrasion; a general principle of disc cutters’ layout design is proposed. Within the model, the relationship among rock uniaxial compressive strength(UCS), penetration and thrust on cutter-head are analyzed, and the results shows that with increasing penetration, cutter thrust increases, but the growth rate slows and higher penetration makes lower special energy(SE). Finally, a fitting mathematical model of ZT(ratio of cutter-head torque and thrust) and penetration is established, and verified by TB880E, which can be used to direct how to set thrust and torque on cutter-head. When penetration is small, the cutter-head thrust is the main limiting factor in tunneling;when the penetration is large, cutter-head torque is the major limiting factor in tunneling. Based on the new cutter-head load model, thrust and torque characteristics of TBM further are researched and a new way for cutter-head layout design and TBM tunneling operations is proposed.

  16. Effect of Spinal Manipulation Thrust Magnitude on Trunk Mechanical Thresholds of Lateral Thalamic Neurons

    Science.gov (United States)

    Reed, William R.; Pickar, Joel G.; Sozio, Randall S.; Long, Cynthia R.

    2014-01-01

    Objectives High velocity low amplitude spinal manipulation (HVLA-SM), as performed by manual therapists (eg, doctors of chiropractic and osteopathy) results in mechanical hypoalgesia in clinical settings. This hypoalgesic effect has previously been attributed to alterations in peripheral and/or central pain processing. The objective of this study was to determine whether thrust magnitude of a simulated HVLA-SM alters mechanical trunk response thresholds in wide dynamic range (WDR) and/or nociceptive specific (NS) lateral thalamic neurons. Methods Extracellular recordings were carried out in the thalamus of 15 anesthetized Wistar rats. Lateral thalamic neurons having receptive fields which included the lumbar dorsal-lateral trunk were characterized as either WDR (n=22) or NS (n=25). Response thresholds to electronic von Frey (rigid tip) mechanical trunk stimuli were determined in three directions (dorsal-ventral, 45°caudalward, and 45°cranialward) prior to and immediately following the dorsal-ventral delivery of a 100ms HVLA-SM at three thrust magnitudes (control, 55%, 85% body weight; (BW)). Results There was a significant difference in mechanical threshold between 85% BW manipulation and control thrust magnitudes in the dorsal-ventral direction in NS neurons (p=.01). No changes were found in WDR neurons at either HVLA-SM thrust magnitude. Conclusions This study is the first to investigate the effect of HVLA-SM thrust magnitude on WDR and NS lateral thalamic mechanical response threshold. Our data suggest that at the single lateral thalamic neuron level, there may be a minimal spinal manipulative thrust magnitude required to elicit an increase in trunk mechanical response thresholds. PMID:24928636

  17. East-west thrusting and anomalous magnetic declinations in the Sierra Gorda, Betic Cordillera, southern Spain

    Science.gov (United States)

    Platzman, E. S.

    1994-01-01

    Structural and palaeomagnetic studies in the Sierra Gorda (Sierra de Loja), located in the External zone of the Betic Cordillera, indicate that westward-directed thrusting is not associated with significant rotations about a vertical axis. Detailed mapping and slip vector analysis show that the Sierra Gorda is a thrust complex composed of three thrust sheets. The uppermost thrust places Early Jurassic pelagic carbonates on top of Jurassic to Oligocene sediments that form a large doubly-plunging footwall syncline. The eastern limb of this syncline has been overturned and is tectonically thinned as a result of the overthrusting. Palaeomagnetic results from Mesozoic and Tertiary sediments both within and around the perimeter of the Sierra Gorda indicate that: (1) the average remanence vector of the seven Late Jurassic localities sampled within the Sierra Gorda has a direction (D = 328° and I = 38°) that is not significantly different from the expected declination for the Upper Jurassic of stable Iberia; and (2) there is no significant difference between the remanences in the two upper thrust sheets indicating that differential rotation did not occur during the initiation and displacement on the thrusts. In contrast, the one Late Jurassic site that was sampled to the west of the Sierra Gorda is rotated, like the rest of the Subbetics, 60° clockwise of the reference direction. The unrotated directions obtained in the Sierra suggest, either that it has rotated in a clockwise sense concordant with the rest of the Subbetic zone and has then been backrotated, or that it has never rotated relative to stable Iberia. In the latter, simpler hypothesis the unrotated declinations may be explained in terms of orthogonal convergence along an irregular continental margin.

  18. Effect of spinal manipulation thrust magnitude on trunk mechanical activation thresholds of lateral thalamic neurons.

    Science.gov (United States)

    Reed, William R; Pickar, Joel G; Sozio, Randall S; Long, Cynthia R

    2014-06-01

    High-velocity low-amplitude spinal manipulation (HVLA-SM), as performed by doctors who use manual therapy (eg, doctors of chiropractic and osteopathy), results in mechanical hypoalgesia in clinical settings. This hypoalgesic effect has previously been attributed to alterations in peripheral and/or central pain processing. The objective of this study was to determine whether thrust magnitude of a simulated HVLA-SM alters mechanical trunk response thresholds in wide dynamic range (WDR) and/or nociceptive specific (NS) lateral thalamic neurons. Extracellular recordings were carried out in the thalamus of 15 anesthetized Wistar rats. Lateral thalamic neurons having receptive fields, which included the lumbar dorsal-lateral trunk, were characterized as either WDR (n=22) or NS (n=25). Response thresholds to electronic von Frey (rigid tip) mechanical trunk stimuli were determined in 3 directions (dorsal-ventral, 45° caudalward, and 45° cranialward) before and immediately after the dorsal-ventral delivery of a 100-millisecond HVLA-SM at 3 thrust magnitudes (control, 55%, 85% body weight). There was a significant difference in mechanical threshold between 85% body weight manipulation and control thrust magnitudes in the dorsal-ventral direction in NS neurons (P=.01). No changes were found in WDR neurons at either HVLA-SM thrust magnitude. This study is the first to investigate the effect of HVLA-SM thrust magnitude on WDR and NS lateral thalamic mechanical response threshold. Our data suggest that, at the single lateral thalamic neuron level, there may be a minimal spinal manipulative thrust magnitude required to elicit an increase in trunk mechanical response thresholds. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

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

    Science.gov (United States)

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

    2016-03-01

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

  20. A conceptual framework of computations in mid-level vision

    Directory of Open Access Journals (Sweden)

    Jonas eKubilius

    2014-12-01

    Full Text Available If a picture is worth a thousand words, as an English idiom goes, what should those words – or, rather, descriptors – capture? What format of image representation would be sufficiently rich if we were to reconstruct the essence of images from their descriptors? In this paper, we set out to develop a conceptual framework that would be: (i biologically plausible in order to provide a better mechanistic understanding of our visual system; (ii sufficiently robust to apply in practice on realistic images; and (iii able to tap into underlying structure of our visual world. We bring forward three key ideas. First, we argue that surface-based representations are constructed based on feature inference from the input in the intermediate processing layers of the visual system. Such representations are computed in a largely pre-semantic (prior to categorization and pre-attentive manner using multiple cues (orientation, color, polarity, variation in orientation and so on, and explicitly retain configural relations between features. The constructed surfaces may be partially overlapping to compensate for occlusions and are ordered in depth (figure-ground organization. Second, we propose that such intermediate representations could be formed by a hierarchical computation of similarity between features in local image patches and pooling of highly-similar units, and reestimated via recurrent loops according to the task demands. Finally, we suggest to use datasets composed of realistically rendered artificial objects and surfaces in order to better understand a model’s behavior and its limitations.

  1. A conceptual framework of computations in mid-level vision

    Science.gov (United States)

    Kubilius, Jonas; Wagemans, Johan; Op de Beeck, Hans P.

    2014-01-01

    If a picture is worth a thousand words, as an English idiom goes, what should those words—or, rather, descriptors—capture? What format of image representation would be sufficiently rich if we were to reconstruct the essence of images from their descriptors? In this paper, we set out to develop a conceptual framework that would be: (i) biologically plausible in order to provide a better mechanistic understanding of our visual system; (ii) sufficiently robust to apply in practice on realistic images; and (iii) able to tap into underlying structure of our visual world. We bring forward three key ideas. First, we argue that surface-based representations are constructed based on feature inference from the input in the intermediate processing layers of the visual system. Such representations are computed in a largely pre-semantic (prior to categorization) and pre-attentive manner using multiple cues (orientation, color, polarity, variation in orientation, and so on), and explicitly retain configural relations between features. The constructed surfaces may be partially overlapping to compensate for occlusions and are ordered in depth (figure-ground organization). Second, we propose that such intermediate representations could be formed by a hierarchical computation of similarity between features in local image patches and pooling of highly-similar units, and reestimated via recurrent loops according to the task demands. Finally, we suggest to use datasets composed of realistically rendered artificial objects and surfaces in order to better understand a model's behavior and its limitations. PMID:25566044

  2. Tropical Cyclone Genesis Efficiency: Mid-Level Versus Bottom Vortex

    Science.gov (United States)

    2011-12-16

    vorticity may affect vorticity segregation (Schecter and Dubin 1999) or VHT merging. It may also affect the inertial stability and hence the efficiency...a MVS develop 15 earlier than MID_VORTEX. Vorticity segregation (Schecter and Dubin 1999) is a possible mechanism for the VHTs merging. That is...D. H. Dubin , 1999: Vortex motion driven by a background vorticity gradient. Phys. Rev. Lett., 83, 2191–2194. Simpson, J., E. Ritchie, G. J. Holland

  3. Mid-level Features Improve Recognition of Interactive Activities

    Science.gov (United States)

    2012-11-14

    Recognizing action as clouds of space-time interest points. In CVPR, 2009. [5] W. Brendel, A. Fern , and S. Todorovic. Probabilistic event logic for interval...context. In CVPR, 2009. [27] R. Messing, C. Pal, and H. Kautz. Activity recognition using the velocity histories of tracked keypoints. In ICCV, 2009

  4. High-Octane Mid-Level Ethanol Blend Market Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Caley [National Renewable Energy Lab. (NREL), Golden, CO (United States); Newes, Emily [National Renewable Energy Lab. (NREL), Golden, CO (United States); Brooker, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); McCormick, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Peterson, Steve [Lexidyne, LLC, Colorado Springs, CO (United States); Leiby, Paul [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Martinez, Rocio Uria [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Oladosu, Gbadebo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Maxwell L. [Colorado School of Mines, Golden, CO (United States)

    2015-12-01

    The United States government has been promoting increased use of biofuels, including ethanol from non-food feedstocks, through policies contained in the Energy Independence and Security Act of 2007. The objective is to enhance energy security, reduce greenhouse gas (GHG) emissions, and provide economic benefits. However, the United States has reached the ethanol blend wall, where more ethanol is produced domestically than can be blended into standard gasoline. Nearly all ethanol is blended at 10 volume percent (vol%) in gasoline. At the same time, the introduction of more stringent standards for fuel economy and GHG tailpipe emissions is driving research to increase the efficiency of spark ignition (SI) engines. Advanced strategies for increasing SI engine efficiency are enabled by higher octane number (more highly knock-resistant) fuels. Ethanol has a research octane number (RON) of 109, compared to typical U.S. regular gasoline at 91-93. Accordingly, high RON ethanol blends containing 20 vol% to 40 vol% ethanol are being extensively studied as fuels that enable design of more efficient engines. These blends are referred to as high-octane fuel (HOF) in this report. HOF could enable dramatic growth in the U.S. ethanol industry, with consequent energy security and GHG emission benefits, while also supporting introduction of more efficient vehicles. HOF could provide the additional ethanol demand necessary for more widespread deployment of cellulosic ethanol. However, the potential of HOF can be realized only if it is adopted by the motor fuel marketplace. This study assesses the feasibility, economics, and logistics of this adoption by the four required participants--drivers, vehicle manufacturers, fuel retailers, and fuel producers. It first assesses the benefits that could motivate these participants to adopt HOF. Then it focuses on the drawbacks and barriers that these participants could face when adopting HOF and proposes strategies--including incentives and policies--to curtail these barriers. These curtailment strategies are grouped into scenarios that are then modeled to investigate their feasibility and explore the dynamics involved in HOF deployment. This report does not advocate for or against incentives or policies, but presents simulations of their effects.

  5. Influence of hydrodynamic thrust bearings on the nonlinear oscillations of high-speed rotors

    Science.gov (United States)

    Chatzisavvas, Ioannis; Boyaci, Aydin; Koutsovasilis, Panagiotis; Schweizer, Bernhard

    2016-10-01

    This paper investigates the effect of hydrodynamic thrust bearings on the nonlinear vibrations and the bifurcations occurring in rotor/bearing systems. In order to examine the influence of thrust bearings, run-up simulations may be carried out. To be able to perform such run-up calculations, a computationally efficient thrust bearing model is mandatory. Direct discretization of the Reynolds equation for thrust bearings by means of a Finite Element or Finite Difference approach entails rather large simulation times, since in every time-integration step a discretized model of the Reynolds equation has to be solved simultaneously with the rotor model. Implementation of such a coupled rotor/bearing model may be accomplished by a co-simulation approach. Such an approach prevents, however, a thorough analysis of the rotor/bearing system based on extensive parameter studies. A major point of this work is the derivation of a very time-efficient but rather precise model for transient simulations of rotors with hydrodynamic thrust bearings. The presented model makes use of a global Galerkin approach, where the pressure field is approximated by global trial functions. For the considered problem, an analytical evaluation of the relevant integrals is possible. As a consequence, the system of equations of the discretized bearing model is obtained symbolically. In combination with a proper decomposition of the governing system matrix, a numerically efficient implementation can be achieved. Using run-up simulations with the proposed model, the effect of thrust bearings on the bifurcations points as well as on the amplitudes and frequencies of the subsynchronous rotor oscillations is investigated. Especially, the influence of the magnitude of the axial force, the geometry of the thrust bearing and the oil parameters is examined. It is shown that the thrust bearing exerts a large influence on the nonlinear rotor oscillations, especially to those related with the conical mode of the

  6. FORMATION AND EVOLUTION OF THE CENOZOIC THRUST FOLD BELT IN JINPING, SICHUAN

    Institute of Scientific and Technical Information of China (English)

    LIAO Zhongli; DENG Yongfu; LIAO Guangyu

    2003-01-01

    The Jinping orogenic belt in Sichuan, China consists mainly of the Jinpingshan intracontinental thrust-nappe belt, foreland thrust-nappe belt and foreland uplift belt. Based on analyses about the characteristics of the structural units in this area, the authors propose in this paper that Chapuzi-Bazhe revival fault belt is the regional boundary fault, and points out that after the formation of the Pre-Sinian basement, the western edge of the Yangtze paraplatform was turned into the passive continental margin in Sinian to Triassic, then into the Mesozoic collision orogenic belt, and finally into the Cenozoic orogenic belt through intracontinental orogeny.

  7. Estimation of optimum operating point for thrust magnetic bearing with solid magnet

    Institute of Scientific and Technical Information of China (English)

    孙首群; 田育民

    2003-01-01

    A carrying capacity-temperature rise analysis model has been established for analysis of the carrying capacity, temperature rise and carrying capacity-temperature rise characteristic of a thrust magnetic bearing with solid magnet. The results indicate that there must be an optimal operating point for the thrust magnetic beating with solid magnet. The main factors having effect on carrying capacity-temperature rise include static gap and/or ampere-turns. With proper static gap chosen, the bearing can be run near the optimal operating point by adjhusting ampere-turns, thereby optimizing the bearing properties.

  8. A reevaluation of the age of the Vincent-Chocolate Mountains thrust system, southern California

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, C.E. (Iowa State Univ., Ames, IA (United States). Dept. of Geological and Atmospheric Sciences); Barth, A.P. (Indiana Univ.--Purdue Univ., Indianapolis, IN (United States). Dept. of Geology)

    1993-04-01

    The Vincent-Chocolate Mountains (VCM) thrust superposes Mesozoic arc plutons and associated Precambrian country rock above subduction-related Pelona-Orocopia schist. The thrust is disrupted in many areas by postmetamorphic deformation, but appears to be intact in the San Gabriel Mountains. Two Rb-Sr mineral-isochron ages from Pelona Schist and mylonite in the San Gabriel Mountains led Ehlig (1981) to conclude that the original thrusting event occurred at c. 60 Ma. However, biotite K-Ar ages determined by Miller and Morton (1980) for upper plate in the same area caused Dillon (1986) to reach a different conclusion. The biotite ages range mainly from 74--60 Ma and increase structurally upward from the VCM thrust. Dillon (1986) inferred that the age gradient was due to uplift and cooling of the upper plate during underthrusting of Pelona Schist. This would indicate that the VCM thrust was at least 74 Ma in age. An alternative to the interpretation of Dillon (1986) is that the biotite age gradient largely predates the VCM thrust. Upward heat flow, leading to older ages at higher structural levels, could have resulted from either static cooling of Cretaceous plutons or uplift and erosion induced by crustal thickening during possible west-directed intra-arc thrusting at c. 88--78 Ma (May and Walker, 1989). Subsequent underthrusting of Pelona Schist would establish a cold lower boundary to the crust and cause the closure of isotopic systems in the base of the upper plate. A 60 Ma time of thrusting is also suggested by two amphibole [sup 40]Ar/[sup 39]Ar ages from the Pelona Schist of the San Gabriel Mountains. Peak metamorphic temperature in this area was below 480 C and amphibole ages should thus indicate time of crystallization rather than subsequent cooling. Four phengite [sup 40]Ar/[sup 39]Ar ages of 55--61 Ma from Pelona Schist and mylonite indicate rapid cooling from peak metamorphic temperatures, consistent with subduction refrigeration.

  9. Orbital Maneuvers Using Low Thrust to Place a Satellite in a Constellation

    Directory of Open Access Journals (Sweden)

    Vivian Martins Gomes

    2007-01-01

    Full Text Available This paper considers the problem of low thrust suboptimal maneuvers to insert a satellite in a constellation. It is assumed that a satellite constellation is given with all the Keplerian elements of the satellite members having known values. Then, it is necessary to maneuver a new satellite from a parking orbit to its position in the constellation. The control available to perform this maneuver is the application of a low thrust to the satellite and the objective is to perform this maneuver with minimum fuel consumption.

  10. A Stiffness-Adjusting Method to Improve Thrust Efficiency of a Two-Joint Robotic Fish

    Directory of Open Access Journals (Sweden)

    Dong Xu

    2014-04-01

    Full Text Available Fish are very efficient swimmers. In this paper, we studied a two degree-of-freedom (DOF propeller that mimic fish caudal fin like locomotion. Kinematics modelling and hydrodynamic CFD analyses of the two DOF propellers were conducted. According to the CFD simulation, we show that negative power was generated within the flapping cycle, and wake flow at different instant was demonstrated. Based on the dynamic model, we compared the thrust efficiency under different stiffness control method. The results show that the thrust efficiency was enhanced under moderate stiffness control strategy.

  11. On INM's Use of Corrected Net Thrust for the Prediction of Jet Aircraft Noise

    Science.gov (United States)

    McAninch, Gerry L.; Shepherd, Kevin P.

    2011-01-01

    The Federal Aviation Administration s (FAA) Integrated Noise Model (INM) employs a prediction methodology that relies on corrected net thrust as the sole correlating parameter between aircraft and engine operating states and aircraft noise. Thus aircraft noise measured for one set of atmospheric and aircraft operating conditions is assumed to be applicable to all other conditions as long as the corrected net thrust remains constant. This hypothesis is investigated under two primary assumptions: (1) the sound field generated by the aircraft is dominated by jet noise, and (2) the sound field generated by the jet flow is adequately described by Lighthill s theory of noise generated by turbulence.

  12. Developmental Testing of Electric Thrust Vector Control Systems for Manned Launch Vehicle Applications

    Science.gov (United States)

    Bates, Lisa B.; Young, David T.

    2012-01-01

    This paper describes recent developmental testing to verify the integration of a developmental electromechanical actuator (EMA) with high rate lithium ion batteries and a cross platform extensible controller. Testing was performed at the Thrust Vector Control Research, Development and Qualification Laboratory at the NASA George C. Marshall Space Flight Center. Electric Thrust Vector Control (ETVC) systems like the EMA may significantly reduce recurring launch costs and complexity compared to heritage systems. Electric actuator mechanisms and control requirements across dissimilar platforms are also discussed with a focus on the similarities leveraged and differences overcome by the cross platform extensible common controller architecture.

  13. A systematic review of thrust manipulation for non-surgical shoulder conditions.

    Science.gov (United States)

    Minkalis, Amy L; Vining, Robert D; Long, Cynthia R; Hawk, Cheryl; de Luca, Katie

    2017-01-01

    Although many conservative management options are available for patients with non-surgical shoulder conditions, there is little evidence of their effectiveness. This review investigated one manual therapy approach, thrust manipulation, as a treatment option. A systematic search was conducted of the electronic databases from inception to March 2016: PubMed, PEDro, ICL, CINAHL, and AMED. Two independent reviewers conducted the screening process to determine article eligibility. Inclusion criteria were manuscripts published in peer-reviewed journals with human participants of any age. The intervention included was thrust, or high-velocity low-amplitude, manipulative therapy directed to the shoulder and/or the regions of the cervical or thoracic spine. Studies investigating secondary shoulder pain or lacking diagnostic confirmation procedures were excluded. Methodological quality was assessed using the PEDro scale and the Cochrane risk-of-bias tool. The initial search rendered 5041 articles. After screening titles and abstracts, 36 articles remained for full-text review. Six articles studying subacromial impingement syndrome met inclusion criteria. Four studies were randomized controlled trials (RCTs) and 2 were uncontrolled clinical studies. Five studies included 1 application of a thoracic spine thrust manipulation and 1 applied 8 treatments incorporating a shoulder joint thrust manipulation. Statistically significant improvements in pain scores were reported in all studies. Three of 4 RCTs compared a thrust manipulation to a sham, and statistical significance in pain reduction was found within the groups but not between them. Clinically meaningful changes in pain were inconsistent; 3 studies reported that scores met minimum clinically important difference, 1 reported scores did not, and 2 were unclear. Four studies found statistically significant improvements in disability; however, 2 were RCTs and did not find statistical significance between the active and sham

  14. Analysis and Control of Axial Thrust in Centrifugal Pump by Use of J-Groove

    OpenAIRE

    Abe, Heishiro; Matsumoto, Kazunari; Kurokawa, Junichi; Matsui, Jun; Choi, Young-Do

    2006-01-01

    In order to control and balance axial thrust of turbo machine, many types of balancing devices are used but most of them are complicated and sometimes cause troubles. In this study, a very simple device of using shallow grooves mounted on a casing wall, known as "J-Groove", is proposed and studied experimentally and theoretically. The result shows that 70% of axial thrust in an industry, 4-stage centrifugal pump can be reduced at the best efficiency point. Moreover, the analytical method of "...

  15. Kinematics of swimming and thrust production during powerstroking bouts of the swim frenzy in green turtle hatchlings

    Directory of Open Access Journals (Sweden)

    David T. Booth

    2014-09-01

    Full Text Available Hatchling sea turtles emerge from nests, crawl down the beach and enter the sea where they typically enter a stereotypical hyperactive swimming frenzy. During this swim the front flippers are moved up and down in a flapping motion and are the primary source of thrust production. I used high-speed video linked with simultaneous measurement of thrust production in tethered hatchlings, along with high-speed video of free swimming hatchlings swimming at different water speeds in a swim flume to investigate the links between kinematics of front flipper movement, thrust production and swimming speed. In particular I tested the hypotheses that (1 increased swimming speed is achieved through an increased stroke rate; (2 force produced per stroke is proportional to stroke amplitude, (3 that forward thrust is produced during both the down and up phases of stroking; and (4 that peak thrust is produced towards the end of the downstroke cycle. Front flipper stroke rate was independent of water speed refuting the hypothesis that swimming speed is increased by increasing stroke rate. Instead differences in swimming speed were caused by a combination of varying flipper amplitude and the proportion of time spent powerstroking. Peak thrust produced per stroke varied within and between bouts of powerstroking, and these peaks in thrust were correlated with both flipper amplitude and flipper angular momentum during the downstroke supporting the hypothesis that stroke force is a function of stroke amplitude. Two distinct thrust production patterns were identified, monophasic in which a single peak in thrust was recorded during the later stages of the downstroke, and biphasic in which a small peak in thrust was recorded at the very end of the upstroke and this followed by a large peak in thrust during the later stages of the downstroke. The biphasic cycle occurs in ∼20% of hatchlings when they first started swimming, but disappeared after one to two hours of

  16. Kinematics of swimming and thrust production during powerstroking bouts of the swim frenzy in green turtle hatchlings.

    Science.gov (United States)

    Booth, David T

    2014-09-04

    Hatchling sea turtles emerge from nests, crawl down the beach and enter the sea where they typically enter a stereotypical hyperactive swimming frenzy. During this swim the front flippers are moved up and down in a flapping motion and are the primary source of thrust production. I used high-speed video linked with simultaneous measurement of thrust production in tethered hatchlings, along with high-speed video of free swimming hatchlings swimming at different water speeds in a swim flume to investigate the links between kinematics of front flipper movement, thrust production and swimming speed. In particular I tested the hypotheses that (1) increased swimming speed is achieved through an increased stroke rate; (2) force produced per stroke is proportional to stroke amplitude, (3) that forward thrust is produced during both the down and up phases of stroking; and (4) that peak thrust is produced towards the end of the downstroke cycle. Front flipper stroke rate was independent of water speed refuting the hypothesis that swimming speed is increased by increasing stroke rate. Instead differences in swimming speed were caused by a combination of varying flipper amplitude and the proportion of time spent powerstroking. Peak thrust produced per stroke varied within and between bouts of powerstroking, and these peaks in thrust were correlated with both flipper amplitude and flipper angular momentum during the downstroke supporting the hypothesis that stroke force is a function of stroke amplitude. Two distinct thrust production patterns were identified, monophasic in which a single peak in thrust was recorded during the later stages of the downstroke, and biphasic in which a small peak in thrust was recorded at the very end of the upstroke and this followed by a large peak in thrust during the later stages of the downstroke. The biphasic cycle occurs in ∼20% of hatchlings when they first started swimming, but disappeared after one to two hours of swimming. The

  17. Control of structural inheritance on thrust initiation and material transfer in accretionary wedges

    Science.gov (United States)

    Leever, Karen; Geersen, Jacob; Ritter, Malte; Lieser, Kathrin; Behrmann, Jan

    2016-04-01

    Faults in the incoming sediment layer are commonly observed in subduction zone settings and well developed in the incoming plate off Sumatra. To investigate how they affect the structural development of the accretionary wedge, we conducted a series of 2D analogue tectonic experiments in which a 2 cm thick quartz sand layer on top of a thin detachment layer of glass beads was pulled against a rigid backstop by a basal conveyor belt in a 20cm wide box with glass walls. A gap at the base of the back wall avoids entrainment of the glass beads. At regular spacing of either 2.3, 5.5 or 7.8 cm (fractions of the thrust sheet length in the reference model), conjugate pairs of weakness zones dipping 60deg were created by cutting the sand layer with a thin (1 mm) metal blade. Both the undisturbed sand and the pre-cuts have an angle of internal friction of ~29o, but their cohesion is different by 50 Pa (110 Pa for the undisturbed material, 60 Pa along the pre-cuts). Friction of the glass beads is ~24deg. The experiments are monitored with high resolution digital cameras; displacement fields derived from digital image correlation are used to constrain fault activity. In all experiments, a critically tapered wedge developed with a surface slope of 7.5deg. In the reference model (no weakness zones in the input section), the position of new thrust faults is controlled by the frontal slope break. The average length of the thrust sheets is 11 cm and the individual thrusts accommodate on average 8 cm displacement each. The presence of weakness zones causes thrust initiation at a position different from the reference case, and affects their dip. For a fault spacing of 7.8 cm (or 75% of the reference thrust sheet length), every single incoming weakness zone causes the formation of a new thrust, thus resulting in thrust sheets shorter than the equilibrium case. In addition, less displacement is accommodated on each thrust. As a consequence, the frontal taper is smaller than expected

  18. Image based measurement techniques for aircraft propeller flow diagnostics: Propeller slipstream investigations at high-lift conditions and thrust reverse

    NARCIS (Netherlands)

    Roosenboom, E.W.M.

    2011-01-01

    The aim of the thesis is to measure the propeller slipstream properties (velocity and vorticity) and to assess the unsteady and instantaneous behavior of the propeller flow field at high disk loadings, zero thrust and thrust reverse using the image based measurement techniques. Along with its implem

  19. Decreased spontaneous activity and altered evoked nociceptive response of rat thalamic submedius neurons to lumbar vertebra thrust.

    Science.gov (United States)

    Reed, William R; Cranston, Jamie T; Onifer, Stephen M; Little, Joshua W; Sozio, Randall S

    2017-07-07

    The thalamus is a central structure important to modulating and processing all mechanoreceptor input destined for the cortex. A large number of diverse mechanoreceptor endings are stimulated when a high velocity low amplitude thrust is delivered to the lumbar spine during spinal manipulation. The objective of this study was to determine if a lumbar thrust alters spontaneous and/or evoked nociceptive activity in medial thalamic submedius (Sm) neurons. Extracellular recordings were obtained from 94 thalamic Sm neurons in 54 urethane-anesthetized adult Wistar rats. Spontaneous activity was recorded 5 min before and after an L5 control (no thrust) and thrust (85% rat body weight; 100 ms) procedure. In a subset of responsive nociceptive-specific neurons, mean changes in noxious-evoked response (10-s pinch with clip; 795 g) at three sites (tail, contra- and ipsilateral hindpaw) were determined following an L5 thrust. Mean changes in Sm spontaneous activity (60 s bins) and evoked noxious response were compared using a mixed model repeated measures ANOVA with Bonferroni post hoc t tests and paired t tests, respectively. Compared to control, spontaneous Sm activity decreased 180-240 s following the lumbar thrust (p thrust compared to control (p thrust suggest that thalamic submedius neurons may play a role in central pain modulation related to manual therapy intervention.

  20. Coupled heat transfer analysis of thrust chambers with recessed shear coaxial injectors

    Science.gov (United States)

    Song, Jiawen; Sun, Bing

    2017-03-01

    To investigate the effects of recessed lengths on combustion performance and heat loads in LOX/methane thrust chambers with shear coaxial injectors, a coupled numerical methodology is developed to solve the combustion and heat transfer in thrust chambers with regenerative cooling. In this methodology, the transcritical turbulent combustion is modeled by a validated non-adiabatic flamelet model considering real-fluid properties; turbulent flows within the thrust chamber and cooling channels are computed by a pressure-based coupled algorithm. The validation indicates that the prediction with detailed chemistry mechanism and the Chung method confirms quantitatively to literature experimental data. The results reveal that the recess causes an increase of wall heat flux in the whole thrust chamber and makes the heat flux peak in the combustion chamber moves downstream. Furthermore, both the heat flux peaks in the combustion chamber and nozzle increase first and then decrease as recessed lengths increase. Meanwhile, chamber pressure, hot-gas temperature, and the averaging heat flux of the combustion chamber wall are positively correlated with recessed lengths. However, the heat loads are more sensitive to the recessed lengths than chamber pressure and hot-gas temperature. Much attention should be paid to the protection of chamber wall.

  1. Quark mass corrections to the perturbative thrust and its effect on the determination of s

    Indian Academy of Sciences (India)

    Sunanda Banerjee; Rahul Basu

    2002-09-01

    We consider the effects of quark masses to the perturbative thrust in +- annihilation. In particular we show that perturbative power corrections resulting from non-zero quark masses considerably alters the size of the non-perturbative power corrections and consequently, significantly changes the fitted value of s.

  2. Experimental measurement of dolphin thrust generated during a tail stand using DPIV

    Science.gov (United States)

    Wei, Timothy; Fish, Frank; Williams, Terrie; Wu, Vicki; Sherman, Erica; Misfeldt, Mitchel; Ringenberg, Hunter; Rogers, Dylan

    2016-11-01

    The thrust generated by dolphins doing tail stands was measured using DPIV. The technique entailed measuring vortex strength associated with the tail motion and correlating it to above water video sequences showing the amount of the dolphin's body that was being lifted out of the water. The underlying drivers for this research included: i) understanding the physiology, hydrodynamics and efficiency of dolphin locomotion, ii) developing non-invasive measurement techniques for studying marine swimming and iii) quantifying the actual propulsive capabilities of these animals. Two different bottlenose dolphins at the Long Marine Lab at UC-Santa Cruz were used as test subjects. Application of the Kutta-Joukowski Theorem on measured vortex circulations yielded thrust values that were well correlated with estimates of dolphin body weight being supported above water. This demonstrates that the tail motion can be interpreted as a flapping hydrofoil that can generate a sustained thrust roughly equal to the dolphin's weight. Videos of DPIV measurements overlaid with the dolphins will be presented along with thrust/weight data.

  3. Pressure and Thrust Measurements of a High-Frequency Pulsed Detonation Tube

    Science.gov (United States)

    Nguyen, N.; Cutler, A. D.

    2008-01-01

    This paper describes measurements of a small-scale, high-frequency pulsed detonation tube. The device utilized a mixture of H2 fuel and air, which was injected into the device at frequencies of up to 1200 Hz. Pulsed detonations were demonstrated in an 8-inch long combustion volume, at about 600 Hz, for the quarter wave mode of resonance. The primary objective of this experiment was to measure the generated thrust. A mean value of thrust was measured up to 6.0 lb, corresponding to H2 flow based specific impulse of 2970 s. This value is comparable to measurements in H2-fueled pulsed detonation engines (PDEs). The injection and detonation frequency for this new experimental case was much higher than typical PDEs, where frequencies are usually less than 100 Hz. The compact size of the device and high frequency of detonation yields a thrust-per-unit-volume of approximately 2.0 pounds per cubic inch, and compares favorably with other experiments, which typically have thrust-per-unit-volume of order 0.01 pound per cubic inch. This much higher volumetric efficiency results in a potentially much more practical device than the typical PDE, for a wide range of potential applications, including high-speed boundary layer separation control, for example in hypersonic engine inlets, and propulsion for small aircraft and missiles.

  4. Pressure and Thrust Measurements of a High-Frequency Pulsed-Detonation Actuator

    Science.gov (United States)

    Nguyen, Namtran C.; Cutler, Andrew D.

    2008-01-01

    This paper describes the development of a small-scale, high-frequency pulsed detonation actuator. The device utilized a fuel mixture of H2 and air, which was injected into the device at frequencies of up to 1200 Hz. Pulsed detonations were demonstrated in an 8-inch long combustion volume, at approx.600 Hz, for the lambda/4 mode. The primary objective of this experiment was to measure the generated thrust. A mean value of thrust was measured up to 6.0 lb, corresponding to specific impulse of 2611 s. This value is comparable to other H2-fueled pulsed detonation engines (PDEs) experiments. The injection and detonation frequency for this new experimental case was approx.600 Hz, and was much higher than typical PDEs, where frequencies are usually less than 100 Hz. The compact size of the model and high frequency of detonation yields a thrust-per-unit-volume of approximately 2.0 lb/cu in, and compares favorably with other experiments, which typically have thrust-per-unit-volume values of approximately 0.01 lb/cu in.

  5. Thrust Belts and Foreland Basins——SGF/SGE Joint Earth Science Meeting

    Institute of Scientific and Technical Information of China (English)

    Olivier Lacombe; Jér(o)me Lavé; Fran(c)ois Roure

    2006-01-01

    @@ What is the important geologic information that thrust belts and foreland basins have recorded on the erogenic evolution of adjacent mountain belts? How can they reveal the coupled influence of deep (flexure, plate rheology and kinematics) and surficial (erosion, sedimentation) geological processes?

  6. Optimization of Process Parameters with Minimum Thrust Force and Torque in Drilling Operation Using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Suleyman Neseli

    2014-10-01

    Full Text Available This research outlines the Taguchi optimization methodology, which is applied to optimize cutting parameters in drilling of AISI 1040 steel. The drilling parameters evaluated are cutting speed, feed rate, and helix angle. Series of experiments are conducted to relate the cutting parameters on the thrust force and torque. L27(313 orthogonal array, signal-to-noise ratio is employed to analyze the influence of these parameters on thrust force and torque during drilling. Analysis of variance (ANOVA is used to study the effect of process parameters on machining process. The study shows that the Taguchi method is suitable to solve the stated problem with the minimum number of trials. The main objective is to find the important factors and combination of factors that influence the machining process to achieve low thrust force and torque. The analysis of the Taguchi method indicates that the feed rate is the most significant factor affecting the thrust force, while the cutting speed contributes the most to the torque.

  7. Contouring Control for a CNC Milling Machine Driven by Direct thrust Controlled Linear Induction Motors

    Directory of Open Access Journals (Sweden)

    Khaled N. Faris

    2015-12-01

    Full Text Available According to various advantages of linear induction motor (LIM, such as high starting thrust force, high speed operation and reduction of mechanical losses, more applications have utilized this type of motors. Direct Thrust Control (DTC technique is considered as one of the most efficient techniques that can be used for LIM. DTC is preferable to give a fast and good dynamic thrust response. So, to improve the accuracy and robustness of contouring control for CNC machine tools, linear induction motors with a direct thrust control technique are introduced for driving these machines. An industry standard motion control system is applied for reducing the tracking error and improving the desired accuracy. Different loading conditions are simulated to validate the reliability and robustness of the introduced system to match the application field. The proposed system is simulated using the MATLAB/SIMULINK Package; simulation results validated both tracking accuracy and robustness of the proposed motion control system for contouring control for a CNC (Computer Numerical Control milling machine.

  8. Thrust-wrench fault interference in a brittle medium: new insights from analogue modelling experiments

    Science.gov (United States)

    Rosas, Filipe; Duarte, Joao; Schellart, Wouter; Tomas, Ricardo; Grigorova, Vili; Terrinha, Pedro

    2015-04-01

    We present analogue modelling experimental results concerning thrust-wrench fault interference in a brittle medium, to try to evaluate the influence exerted by different prescribed interference angles in the formation of morpho-structural interference fault patterns. All the experiments were conceived to simulate simultaneous reactivation of confining strike-slip and thrust faults defining a (corner) zone of interference, contrasting with previously reported discrete (time and space) superposition of alternating thrust and strike-slip events. Different interference angles of 60°, 90° and 120° were experimentally investigated by comparing the specific structural configurations obtained in each case. Results show that a deltoid-shaped morpho-structural pattern is consistently formed in the fault interference (corner) zone, exhibiting a specific geometry that is fundamentally determined by the different prescribed fault interference angle. Such angle determines the orientation of the displacement vector shear component along the main frontal thrust direction, determining different fault confinement conditions in each case, and imposing a complying geometry and kinematics of the interference deltoid structure. Model comparison with natural examples worldwide shows good geometric and kinematic similarity, pointing to the existence of matching underlying dynamic process. Acknowledgments This work was sponsored by the Fundação para a Ciência e a Tecnologia (FCT) through project MODELINK EXPL/GEO-GEO/0714/2013.

  9. Structural Geochemical Study of the Yuxi Fold-Thrust Belt in the Southern North China Plate

    Institute of Scientific and Technical Information of China (English)

    Li Wenyong; Xia Bin; Li Dongxu

    2006-01-01

    The Yuxi (豫西) fold-thrust fracture belt is part of the gigantic fold-thrust fracture belt that extends NW in the southern North China plate. The contents of major elements of tectonites were analyzed by ICP-AES. The analysis of chemical compositions and new stress minerals indicates: extending from the surrounding country rocks to the center of the fracture belt, the Fe2 O3 content gradually increases while the FeO content gradually decreases; regular increase, decrease or peak changes are shown for chemical compositions likeSiO2, Al2O3, Fe2O3, MgO, CaO, FeO, loss on ignition, TiO2,K2O, Na2O, etc.. New stress minerals are developed for the south branch and few for the north branch.The characteristics of chemical compositions and new stress minerals of the thrust fracture demonstrate that the fracture belt has undergone a process from a closed reducing environmental system to a relatively open, oxidizing environmental system, and compressive fractures have resulted from compression in the late stages of evolution, and the dynamothermal metamorphism and thrusting intensities are different between the south and north branches of the belt, which is strong for the south branch but relatively weak for the north branch.

  10. The complete two-loop integrated jet thrust distribution in soft-collinear effective theory

    Energy Technology Data Exchange (ETDEWEB)

    von Manteuffel, Andreas; Schabinger, Robert M.; Zhu, Hua Xing

    2014-03-01

    In this work, we complete the calculation of the soft part of the two-loop integrated jet thrust distribution in e+e- annihilation. This jet mass observable is based on the thrust cone jet algorithm, which involves a veto scale for out-of-jet radiation. The previously uncomputed part of our result depends in a complicated way on the jet cone size, r, and at intermediate stages of the calculation we actually encounter a new class of multiple polylogarithms. We employ an extension of the coproduct calculus to systematically exploit functional relations and represent our results concisely. In contrast to the individual contributions, the sum of all global terms can be expressed in terms of classical polylogarithms. Our explicit two-loop calculation enables us to clarify the small r picture discussed in earlier work. In particular, we show that the resummation of the logarithms of r that appear in the previously uncomputed part of the two-loop integrated jet thrust distribution is inextricably linked to the resummation of the non-global logarithms. Furthermore, we find that the logarithms of r which cannot be absorbed into the non-global logarithms in the way advocated in earlier work have coefficients fixed by the two-loop cusp anomalous dimension. We also show that in many cases one can straightforwardly predict potentially large logarithmic contributions to the integrated jet thrust distribution at L loops by making use of analogous contributions to the simpler integrated hemisphere soft function.

  11. Optimization of Low-Thrust Earth-Moon Transfers Using Evolutionary Neurocontrol

    NARCIS (Netherlands)

    Ohndorf, A.; Dachwald, B.; Gill, E.K.A.

    2009-01-01

    Although low-thrust propulsion is an interesting option for scientific and reconnaissance missions to targets in planetary space, like the Moon, associated transfer strategies pose challenging requirements in terms of optimal control. The method of Evolutionary Neurocontrol (ENC), which has been app

  12. Differential Tectonic Deformation of the Longmen Mountain Thrust Belt,Western Sichuan Basin,China

    Institute of Scientific and Technical Information of China (English)

    TANG Liangjie; YANG Keming; JIN Wenzheng; WAN Guime; L(U) Zhizhou; YU Yixin

    2009-01-01

    Field investigation and seismic section explanation showed that the Longmen Mountain Thrust Belt has obvious differential deformation:zonation,segmentation and stratification.Zonation means that, from NW to NE.the Longmen Mountain Thrust Belt can be divided into the Songpan. foreland depression.Segmentation means that it can be divided into five segments from north to South: the northern segment,the Anxian Transfer Zone,the center segment,the Guanxian Transfer Zone and the southern segment.Stratification means that the detachment layers partition the structural styles in profile.The detachment layers in the Longmen Mountain Thrust Belt can be classified into three categories:the deep-level detachment layers,including the crust-mantle system detachment layer. intracrustaI detachment layer.and Presinian system basal detachment layer;the middle.1evel detachment layers, including Cambrian-Ordovician detachment layer, Silurian detachment layer,etc.: and shallow-level detachment layers,including Upper Triassic Xujiahe Formation detachment layer and the Jurassic detachment layers.The multi-level detachment layers have a very important effect on the shaping and evolution of Longmen Mountain Thrust Belt.

  13. Estimates of trapped radiation encountered on low-thrust trajectories through the Van Allen belts

    Science.gov (United States)

    Karp, I. M.

    1973-01-01

    Estimates were made of the number of trapped protons and electrons encountered by vehicles on low-thrust trajectories through the Van Allen belts. The estimates serve as a first step in assessing whether these radiations present a problem to on-board sensitive components and payload. The integrated proton spectra and electron spectra are presented for the case of a trajectory described by a vehicle with a constant-thrust acceleration A sub c equal to 0.001 meter/sq sec. This value of acceleration corresponds to a trip time of about 54 days from low earth orbit to synchronous orbit. It is shown that the time spent in the belts and hence the radiation encountered vary nearly inversely with the value of thrust acceleration. Thus, the integrated spectral values presented for the case of A sub c = 0.001 meter/sq sec can be generalized for any other value of thrust acceleration by multiplying them by the factor 0.001/A sub c.

  14. Thrust enhancement via gel-type liquid confinement of laser ablation of solid metal propellant

    Science.gov (United States)

    Choi, Soojin; Han, Tae-Hee; Gojani, Ardian B.; Yoh, Jack J.

    2010-01-01

    Laser propulsion has been developed as a suitable small thruster technology for the attitude control of micro and nano class satellites. Laser-based thrusters meet the satellite design criteria for being of light weight and cost effective, because they do not require fuel storing and oxidizer for combustion. Also, thrust control by laser propulsion is achieved fairly easy. In this paper, we consider the confinement of plasma expansion by a gel-type liquid material, which results in the enhancement of the thrust for propulsion. We also present our attempts to resolve some known issues regarding laser ablation of solid and liquid targets. The level of thrust is quantified via the momentum coupling coefficient, which was experimentally measured using a ballistic pendulum system. We have discovered that the laser ablation confinement by the gel-type medium results in 2.3 times more enhanced driving force as compared to the water confinement. A proof of performance is demonstrated for using gel-type material for generating propulsion, and material characterization for optimal thrust performance is presented.

  15. Thrust enhancement via gel-type liquid confinement of laser ablation of solid metal propellant

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Soojin; Han, Tae-hee; Gojani, Ardian B.; Yoh, Jack J. [Seoul National University, School of Mechanical and Aerospace Engineering, Seoul (Korea)

    2010-01-15

    Laser propulsion has been developed as a suitable small thruster technology for the attitude control of micro and nano class satellites. Laser-based thrusters meet the satellite design criteria for being of light weight and cost effective, because they do not require fuel storing and oxidizer for combustion. Also, thrust control by laser propulsion is achieved fairly easy. In this paper, we consider the confinement of plasma expansion by a gel-type liquid material, which results in the enhancement of the thrust for propulsion. We also present our attempts to resolve some known issues regarding laser ablation of solid and liquid targets. The level of thrust is quantified via the momentum coupling coefficient, which was experimentally measured using a ballistic pendulum system. We have discovered that the laser ablation confinement by the gel-type medium results in 2.3 times more enhanced driving force as compared to the water confinement. A proof of performance is demonstrated for using gel-type material for generating propulsion, and material characterization for optimal thrust performance is presented. (orig.)

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

    Science.gov (United States)

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

    1973-01-01

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

  17. Lateral continuity of the Blarney Creek Thrust, Doonerak Windown, Central Brooks Range, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Seidensticker, C.M.; Julian, F.E.; Phelps, J.C.; Oldow, J.S.; Avellemant, H.G.

    1985-04-01

    The contact between Carboniferous and lower Paleozoic rocks, exposed along the northern margin of the Doonerak window in the central Brooks Range, is a major thrust fault called the Blarney Creek thrust (BCT). The BCT has been traced over a distance of 25 km, from Falsoola Mountain to Wien Mountain. The tectonic nature of this contact is demonstrated by: (1) omission of stratigraphic units above and below the BCT; (2) large angular discordance in orientation of first-generation cleavage at the BCT; (3) numerous thrust imbricates developed in the upper-plate Carboniferous section that sole into the BCT; and (4) truncation of an upper-plate graben structure at the BCT. Lack of evidence for pre-Carboniferous deformation in the lower plate casts doubt on the interpretation of the contact as an angular unconformity. However, the localized presence below the BCT of Mississippian Kekiktuk Conglomerate and Kayak Shale, in apparent depositional contact with lower Paleozoic rocks, suggests that the BCT follows an originally disconformable contact between the Carboniferous and lower Paleozoic rocks. The juxtaposition of younger over older rocks at the BCT is explained by calling upon the BCT to act as the upper detachment surface of a duplex structure. Duplex development involves initial imbrication of the Carboniferous section using the BCT as a basal decollement, followed by formation of deeper thrusts in the lower Paleozoic section, which ramp up and merge into the BCT.

  18. Potential Applications of the Ceramic Thrust Chamber Technology for Future Transpiration Cooled Rocket Engines

    Science.gov (United States)

    Herbertz, Armin; Ortelt, Markus; Müller, Ilja; Hald, Hermann

    The long-term development of ceramic rocket engine thrust chambers at the German Aerospace Center(DLR) currently leads to designs of self-sustaining, transpiration-cooled, fiber-reinforced ceramic rocket engine chamber structures.This paper discusses characteristic issues and potential benefits introduced by this technology. Achievable benefits are the reduction of weight and manufacturing cost, as well as an increased reliability and higher lifetime due to thermal cycle stability.Experiments with porous Ceramic Matrix Composite(CMC) materials for rocket engine chamber walls have been conducted at the DLR since the end of the 1990s.This paper discusses the current status of DLR's ceramic thrust chamber technology and potential applications for high thrust engines.The manufacturing process and the design concept are explained.The impact of variations of engine parameters(chamber pressure and diam-eter)on the required coolant mass flow are discussed.Due to favorable scaling effects a high thrust application utilizes all benefits of the discussed technology, while avoiding the most significant performance drawbacks.

  19. Flow measurement and thrust estimation of a vibrating ionic polymer metal composite

    Science.gov (United States)

    Chae, Woojin; Cha, Youngsu; Peterson, Sean D.; Porfiri, Maurizio

    2015-09-01

    Ionic polymer metal composites (IPMCs) are an emerging class of soft active materials that are finding growing application as underwater propulsors for miniature biomimetic swimmers. Understanding the hydrodynamics generated by an IPMC vibrating under water is central to the design of such biomimetic swimmers. In this paper, we propose the use of time-resolved particle image velocimetry to detail the fluid kinematics and kinetics in the vicinity of an IPMC vibrating along its fundamental structural mode. The reconstructed pressure field is ultimately used to estimate the thrust produced by the IPMC. The vibration frequency is systematically varied to elucidate the role of the Reynolds number on the flow physics and the thrust production. Experimental results indicate the formation and shedding of vortical structures from the IPMC tip during its vibration. Vorticity shedding is sustained by the pressure gradients along each side of the IPMC, which are most severe in the vicinity of the tip. The mean thrust is found to robustly increase with the Reynolds number, closely following a power law that has been derived from direct three-dimensional numerical simulations. A reduced order distributed model is proposed to describe IPMC underwater vibration and estimate thrust production, offering insight into the physics of underwater propulsion and aiding in the design of IPMC-based propulsors.

  20. Study on development of ejector of Bubble Jet Engine (BJE) - measurement of thrust -

    Energy Technology Data Exchange (ETDEWEB)

    Ono, B; Nakashima, K; Shigematsu, T; Morishita, K, E-mail: ono@post.cc.sasebo.ac.j [Sasebo National College of Technology1-1, Okishin-cho, Sasebo City, Nagasaki Pref., 857-1193 (Japan)

    2009-02-01

    The AUV (Autonomous Under-water Vehicle), which is used for the present seabed investigations, has obtained the thrust with the screw driven by the battery. However, it has a disadvantage because of its size and cost. Therefore, this research is carried out to propose the Bubble Jet Engine (BJE) as an alternative propulsion device. It can directly transform combustion energy into kinetic energy, so it is expected that BJE can also rise the level of propulsion efficiency. This research aims at measuring exhaled mass flow rate and thrust to design ejectors, which become the core of BJE, and exploring practical possibility of BJE. Vertical type gas-water ejector experimental apparatus for measuring water entrainment was employed in order to understand the characteristics of operation conditions, such as inlet distance, air pressure of nozzle, diameter of nozzle, and so on. In addition, experiments for measuring the thrust in the condition of ejector were executed with horizontal type apparatus in water. However, the influence of the ejector to improve thrust can't have been recognized with high-pressure air at room temperature yet.

  1. Study on development of ejector of Bubble Jet Engine (BJE) - measurement of thrust -

    Science.gov (United States)

    Ono, B.; Nakashima, K.; Shigematsu, T.; Morishita, K.

    2009-02-01

    The AUV (Autonomous Under-water Vehicle), which is used for the present seabed investigations, has obtained the thrust with the screw driven by the battery. However, it has a disadvantage because of its size and cost. Therefore, this research is carried out to propose the Bubble Jet Engine (BJE) as an alternative propulsion device. It can directly transform combustion energy into kinetic energy, so it is expected that BJE can also rise the level of propulsion efficiency. This research aims at measuring exhaled mass flow rate and thrust to design ejectors, which become the core of BJE, and exploring practical possibility of BJE. Vertical type gas-water ejector experimental apparatus for measuring water entrainment was employed in order to understand the characteristics of operation conditions, such as inlet distance, air pressure of nozzle, diameter of nozzle, and so on. In addition, experiments for measuring the thrust in the condition of ejector were executed with horizontal type apparatus in water. However, the influence of the ejector to improve thrust can't have been recognized with high-pressure air at room temperature yet.

  2. Structural Evolution of the Eastern Qiulitagh Fold and Thrust Belt, Northern Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    YANG Minghui; JIN Zhijun; LU Xiuxiang; SUN Dongsheng; TANG Xuan; PENG Gengxin; LEI Ganglin

    2009-01-01

    The eastern Qiulitagh fold and thrust belt (EQFTB) is part of the active Kuqa fold and thrust belts of the northern Tarirn Basin. Seismic reflection profiles have been integrated with surface geologic and drill data to examine the deformation and structure style of the EQFTB, particularly the deformational history of the Dina 2 gas field. Seismic interpretations suggest that Dongqiu 8 is overall a duplex structure developed beneath a passive roof thrust, which generated from a tipline in the Miocene Jidike Formation, and the sole thrust was initiated from the same Jidike Formation evaporite zone that extends westward beneath the Kuqatawu anticline. Dongqiu 5 is a pop-up structure at the western part of the EQFTB, also developed beneath the Jidike Formation evaporite. Very gentle basement dip and steep dipping topographic slope in the EQFTB suggest that the Jidike Formation salt provides effective decoupling. The strong deformation in the EQFTB appears to have developed further south, in an area where evaporite may be lacking. Since the Pliocene, the EQFTB has moved farther south over the evaporite and reached the Yaken area. Restoring a balanced cross-section suggests that the minimum shortening across the EQFTB is more than 7800 m. Assuming that this shortening occurred during the 5.3 Ma timespan, the shortening rate is approximately 1.47 ram/year.

  3. Neandertal humeri may reflect adaptation to scraping tasks, but not spear thrusting.

    Science.gov (United States)

    Shaw, Colin N; Hofmann, Cory L; Petraglia, Michael D; Stock, Jay T; Gottschall, Jinger S

    2012-01-01

    Unique compared with recent and prehistoric Homo sapiens, Neandertal humeri are characterised by a pronounced right-dominant bilateral strength asymmetry and an anteroposteriorly strengthened diaphyseal shape. Remodeling in response to asymmetric forces imposed during regular underhanded spear thrusting is the most influential explanatory hypothesis. The core tenet of the "Spear Thrusting Hypothesis", that underhand thrusting requires greater muscle activity on the right side of the body compared to the left, remains untested. It is unclear whether alternative subsistence behaviours, such as hide processing, might better explain this morphology. To test this, electromyography was used to measure muscle activity at the primary movers of the humerus (pectoralis major (PM), anterior (AD) and posterior deltoid (PD)) during three distinct spear-thrusting tasks and four separate scraping tasks. Contrary to predictions, maximum muscle activity (MAX) and total muscle activity (TOT) were significantly higher (all values, pscraping tasks, right side MAX and TOT were significantly greater at the AD (all values, pscraping activities, such as hide preparation, may be a key behaviour in determining the unusual pattern of Neandertal arm morphology. Overall, these results yield important insight into the Neandertal behavioural repertoire that aided survival throughout Pleistocene Eurasia.

  4. Investigation on Novel Methods to Increase Specific Thrust in Pulse Detonation Engines via Imploding Detonations

    Science.gov (United States)

    2009-12-01

    to-Detonation Transition, Specific Thrust 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS...hydrocarbon fuel-air mixtures such as acetylene -air, ethylene-air, propane-air and even JP10-air mixtures based on the required length of the induction zone

  5. Analysis of a Thrust Bearing with Flexible Pads and Flexible Supports

    DEFF Research Database (Denmark)

    Klit, Peder; Thomsen, Kim

    2007-01-01

    A theoretical analysis of a hydrodynamic thrust bearing is presented. The bearing investigated is used in an ndustrial product. The lubricant is water, but the results are valid also for other lubricants.At first the results from a 1-dimensional model for the fluid film forces and the associated...

  6. Optimal design of Tilting-Pad Thrust Bearings with High Pressure Injection Pockets

    DEFF Research Database (Denmark)

    Heinrichson, Niels; Santos, Ilmar

    2006-01-01

    A thermo-elasto-hydrodynamic(TEHD) model based on the Reynolds equation has been used to study the effect of oil injection pockets on the performance of tilting pad thrust bearings. The optimal position of the pivot both with respect to load carrying capacity and minimal power consumption is seen...

  7. Measurement of Pressure Fluctuations inside a Model Thrust Bearing Using PVDF Sensors.

    Science.gov (United States)

    Youssef, Andrew; Matthews, David; Guzzomi, Andrew; Pan, Jie

    2017-04-16

    Thrust bearings play a vital role in propulsion systems. They rely on a thin layer of oil being trapped between rotating surfaces to produce a low friction interface. The "quality" of this bearing affects many things from noise transmission to the ultimate catastrophic failure of the bearing itself. As a result, the direct measure of the forces and vibrations within the oil filled interface would be very desirable and would give an indication of the condition of the bearing in situ. The thickness of the oil film is, however, very small and conventional vibration sensors are too cumbersome to use in this confined space. This paper solves this problem by using a piezoelectric polymer film made from Polyvinylidine Fluoride (PVDF). These films are very thin (50 m) and flexible and easy to install in awkward spaces such as the inside of a thrust bearing. A model thrust bearing was constructed using a 3D printer and PVDF films inserted into the base of the bearing. In doing so, it was possible to directly measure the force fluctuations due to the rotating pads and investigate various properties of the thrust bearing itself.

  8. The Thrust Plate Prosthesis: long-term clinical and radiological results.

    Science.gov (United States)

    Diederix, Leon W; Van Winterswijk, Peter J T S; Schouten, Sander B; Bakx, Pieter A G M; Huij, Jaap

    2013-06-01

    The Thrust Plate Prosthesis is a femoral implant designed for total hip arthroplasty, based on the principles of physiologic loading of the metaphysis of the proximal femur, and preserving the bone stock. This study presents the long-term clinical and radiological results of 34 patients with 36 Thrust Plate Prostheses. In a retrospective analysis, we investigated the reoperation-free survival as well as the clinical and radiological results. Mean age at operation was 51 +/- 6.4 years. Mean follow-up length was 11.9 +/- 1.6 years. Reoperation-free survival was 88.9%. Four (11.1%) reoperations were performed, in three patients due to aseptic loosening and in one patient because of a fracture distal to the lateral plate. Three of the reoperations were performed between 12 and 32 months postoperatively. The major complaint was pain at the lateral side of the hip (44%). Radiolucencies did not exceed 1 mm, but 35% of the hips showed resorption of the cortex directly under the thrust plate, together with cancellous bone hypertrophy at the calcar, noted in 97%. Because of the relatively high reoperation-free survival and favourable radiological results, the Thrust Plate Prosthesis appears as a possible alternative to stemmed total hip arthroplasty, especially in relatively young patients.

  9. Optimization of Low-Thrust Earth-Moon Transfers Using Evolutionary Neurocontrol

    NARCIS (Netherlands)

    Ohndorf, A.; Dachwald, B.; Gill, E.K.A.

    2009-01-01

    Although low-thrust propulsion is an interesting option for scientific and reconnaissance missions to targets in planetary space, like the Moon, associated transfer strategies pose challenging requirements in terms of optimal control. The method of Evolutionary Neurocontrol (ENC), which has been

  10. Simulation of Liquid Injection Thrust Vector Control for Mars Ascent Vehicle

    Science.gov (United States)

    Gudenkauf, Jared

    2017-01-01

    The Jet Propulsion Laboratory is currently in the initial design phase for a potential Mars Ascent Vehicle; which will be landed on Mars, stay on the surface for period of time, collect samples from the Mars 2020 rover, and then lift these samples into orbit around Mars. The engineers at JPL have down selected to a hybrid wax-based fuel rocket using a liquid oxidizer based on nitrogen tetroxide, or a Mixed Oxide of Nitrogen. To lower the gross lift-off mass of the vehicle the thrust vector control system will use liquid injection of the oxidizer to deflect the thrust of the main nozzle instead of using a gimbaled nozzle. The disadvantage of going with the liquid injection system is the low technology readiness level with a hybrid rocket. Presented in this paper is an effort to simulate the Mars Ascent Vehicle hybrid rocket nozzle and liquid injection thrust vector control system using the computational fluid dynamic flow solver Loci/Chem. This effort also includes determining the sensitivity of the thrust vector control system to a number of different design variables for the injection ports; including axial location, number of adjacent ports, injection angle, and distance between the ports.

  11. Optimal design of Tilting-Pad Thrust Bearings with High Pressure Injection Pockets

    DEFF Research Database (Denmark)

    Heinrichson, Niels; Santos, Ilmar

    2006-01-01

    A thermo-elasto-hydrodynamic(TEHD) model based on the Reynolds equation has been used to study the effect of oil injection pockets on the performance of tilting pad thrust bearings. The optimal position of the pivot both with respect to load carrying capacity and minimal power consumption is seen...

  12. Geometric factors affecting noise suppresion and thrust loss of divergent-lobe supersonic jet noise suppressor

    Science.gov (United States)

    Huff, R. G.; Groesbeck, D. E.

    1973-01-01

    The thrust loss and noise suppression of a divergent-lobe supersonic jet noise suppressor were experimentally determined over a range of nozzle pressure ratios of 1.5 to 4.0. These small-scale cold flow tests were made to determine the effect on thrust and noise of: suppressor length, rearward facing step height, suppressor divergence angle, and ejector shroud length and location. Noise suppression was achieved at nozzle pressure ratios of 2.5 and greater. Maximum lobe jet noise attenuation of 15 db with thrust loss differences of 1.5 percent compared to the convergent nozzle were obtained at a nozzle pressure ratio of 3.5 with an ejector shroud two nozzle diameters long. Without the ejector the attenuation was 13 db with thrust loss differences of 11 percent. Short suppressors approximately one primary nozzle throat diameter long performed as well as longer suppressors. Rearward facing step height had a significant effect on noise suppression. Ejector shrouds two nozzle diameters in length are feasible.

  13. Static performance of nonaxisymmetric nozzles with yaw thrust-vectoring vanes

    Science.gov (United States)

    Mason, Mary L.; Berrier, Bobby L.

    1988-01-01

    A static test was conducted in the static test facility of the Langley 16 ft Transonic Tunnel to evaluate the effects of post exit vane vectoring on nonaxisymmetric nozzles. Three baseline nozzles were tested: an unvectored two dimensional convergent nozzle, an unvectored two dimensional convergent-divergent nozzle, and a pitch vectored two dimensional convergent-divergent nozzle. Each nozzle geometry was tested with 3 exit aspect ratios (exit width divided by exit height) of 1.5, 2.5 and 4.0. Two post exit yaw vanes were externally mounted on the nozzle sidewalls at the nozzle exit to generate yaw thrust vectoring. Vane deflection angle (0, -20 and -30 deg), vane planform and vane curvature were varied during the test. Results indicate that the post exit vane concept produced resultant yaw vector angles which were always smaller than the geometric yaw vector angle. Losses in resultant thrust ratio increased with the magnitude of resultant yaw vector angle. The widest post exit vane produced the largest degree of flow turning, but vane curvature had little effect on thrust vectoring. Pitch vectoring was independent of yaw vectoring, indicating that multiaxis thrust vectoring is feasible for the nozzle concepts tested.

  14. Two-dimensional confined jet thrust vector control: Operating mechanisms and performance

    Science.gov (United States)

    Caton, Jeffrey L.

    1989-03-01

    An experimental investigation of two-dimensional confined jet thrust vector control nozzles was performed. Thrust vector control was accomplished by using secondary flow injection in the diverging section of the nozzle. Schlieren photographs and video tapes were used to study flow separation and internal shock structures. Nozzle performance parameters were determined for nozzle flow with and without secondary flows. These parameters included nozzles forces, vector angles, thrust efficiencies, and flow switching response times. Vector angles as great as 18 degrees with thrust efficiencies of 0.79 were measured. Several confined jet nozzles with variations in secondary flow port design were tested and results were compared to each other. Converging-diverging nozzles of similar design to the confined jet nozzles were also tested and results were compared to the confined jet nozzle results. Existing prediction models for nozzle side to axial force ratio were evaluated. A model for nozzle total forces based on shock losses that predicted values very close to actual results was developed.

  15. Static investigation of two STOL nozzle concepts with pitch thrust-vectoring capability

    Science.gov (United States)

    Mason, M. L.; Burley, J. R., II

    1986-01-01

    A static investigation of the internal performance of two short take-off and landing (STOL) nozzle concepts with pitch thrust-vectoring capability has been conducted. An axisymmetric nozzle concept and a nonaxisymmetric nozzle concept were tested at dry and afterburning power settings. The axisymmetric concept consisted of a circular approach duct with a convergent-divergent nozzle. Pitch thrust vectoring was accomplished by vectoring the approach duct without changing the nozzle geometry. The nonaxisymmetric concept consisted of a two dimensional convergent-divergent nozzle. Pitch thrust vectoring was implemented by blocking the nozzle exit and deflecting a door in the lower nozzle flap. The test nozzle pressure ratio was varied up to 10.0, depending on model geometry. Results indicate that both pitch vectoring concepts produced resultant pitch vector angles which were nearly equal to the geometric pitch deflection angles. The axisymmetric nozzle concept had only small thrust losses at the largest pitch deflection angle of 70 deg., but the two-dimensional convergent-divergent nozzle concept had large performance losses at both of the two pitch deflection angles tested, 60 deg. and 70 deg.

  16. Design and development of a quiet, self-thrusting blast hole

    CSIR Research Space (South Africa)

    Ottermann, RW

    2001-08-01

    Full Text Available percussion drills are a major contributor to noise-induced hearing impairment in mines. The design and development of a quiet, self-thrusting blast hole drilling system will reduce this risk. During this project such a drilling system was developed, tested...

  17. Upper crustal mechanical stratigraphy and the evolution of thrust wedges: insights from sandbox analogue experiments

    Science.gov (United States)

    Milazzo, Flavio; Storti, Fabrizio; Nestola, Yago; Cavozzi, Cristian; Magistroni, Corrado; Meda, Marco; Salvi, Francesca

    2016-04-01

    Crustal mechanical stratigraphy i.e. alternating mechanically weaker and stronger layers within the crust, plays a key role in determining how contractional deformations are accommodated at convergent plate boundaries. In the upper crust, evaporites typically provide preferential décollement layers for fault localization and foreland ward propagation, thus significantly influencing evolution of thrust-fold belts in terms of mechanical balance, geometries, and chronological sequences of faulting. Evaporites occur at the base of many passive margin successions that underwent positive inversion within orogenic systems. They typically produce salient geometries in deformation fronts, as in the Jura in the Northern Alps, the Salakh Arch in the Oman Mountains, or the Ainsa oblique thrust-fold belt in the Spanish Pyrenees. Evaporites frequently occur also in foredeep deposits, as in the Apennines, the Pyrenees, the Zagros etc. causing development of additional structural complexity. Low-friction décollement layers also occur within sedimentary successions involved in thrust-fold belts and they contribute to the development of staircase fault trajectories. The role of décollement layers in thrust wedge evolution has been investigated in many experimental works, particularly by sandbox analogue experiments that have demonstrated the impact of basal weak layers on many first order features of thrust wedges, including the dominant fold vergence, the timing of fault activity, and the critical taper. Some experiments also investigated on the effects of weak layers within accreting sedimentary successions, showing how this triggers kinematic decoupling of the stratigraphy above and below the décollements, thus enhancing disharmonic deformation. However, at present a systematic experimental study of the deformation modes of an upper crustal mechanical stratigraphy consisting of both low-friction and viscous décollement layers is still missing in the specific literature. In

  18. A Thrust Allocation Method for Efficient Dynamic Positioning of a Semisubmersible Drilling Rig Based on the Hybrid Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Luman Zhao

    2015-01-01

    Full Text Available A thrust allocation method was proposed based on a hybrid optimization algorithm to efficiently and dynamically position a semisubmersible drilling rig. That is, the thrust allocation was optimized to produce the generalized forces and moment required while at the same time minimizing the total power consumption under the premise that forbidden zones should be taken into account. An optimization problem was mathematically formulated to provide the optimal thrust allocation by introducing the corresponding design variables, objective function, and constraints. A hybrid optimization algorithm consisting of a genetic algorithm and a sequential quadratic programming (SQP algorithm was selected and used to solve this problem. The proposed method was evaluated by applying it to a thrust allocation problem for a semisubmersible drilling rig. The results indicate that the proposed method can be used as part of a cost-effective strategy for thrust allocation of the rig.

  19. Thrust vectoring of an electric solar wind sail with a realistic sail shape

    Science.gov (United States)

    Toivanen, P.; Janhunen, P.

    2017-02-01

    The shape of a rotating electric solar wind sail under the centrifugal force and solar wind dynamic pressure is modeled to address the sail attitude maintenance and thrust vectoring. The sail rig assumes centrifugally stretched main tethers that extend radially outward from the spacecraft in the sail spin plane. Furthermore, the tips of the main tethers host remote units that are connected by auxiliary tethers at the sail rim. Here, we derive the equation of main tether shape and present both a numerical solution and an analytical approximation for the shape as parametrized both by the ratio of the electric sail force to the centrifugal force and the sail orientation with respect to the solar wind direction. The resulting shape is such that near the spacecraft, the roots of the main tethers form a cone, whereas towards the rim, this coning is flattened by the centrifugal force, and the sail is coplanar with the sail spin plane. Our approximation for the sail shape is parametrized only by the tether root coning angle and the main tether length. Using the approximate shape, we obtain the torque and thrust of the electric sail force applied to the sail. As a result, the amplitude of the tether voltage modulation required for the maintenance of the sail attitude is given as a torque-free solution. The amplitude is smaller than that previously obtained for a rigid single tether resembling a spherical pendulum. This implies that less thrusting margin is required for the maintenance of the sail attitude. For a given voltage modulation, the thrust vectoring is then considered in terms of the radial and transverse thrust components.

  20. One-equation modeling and validation of dielectric barrier discharge plasma actuator thrust

    Science.gov (United States)

    Yoon, Jae-San; Han, Jae-Hung

    2014-10-01

    Dielectric barrier discharge (DBD) plasma actuators with an asymmetric electrode configuration can generate a wall-bounded jet without mechanical moving parts, which require considerable modifications of existing aeronautical objects and which incur high maintenance costs. Despite this potential, one factor preventing the wider application of such actuators is the lack of a reliable actuator model. It is difficult to develop such a model because calculating the ion-electric field and fluid interaction consume a high amount calculation effort during the numerical analysis. Thus, the authors proposed a semi-empirical model which predicted the thrust of plasma actuators with a simple equation. It gave a numeric thrust value, and we implemented the value on a computational fluid dynamics (CFD) solver to describe the two-dimensional flow field induced by the actuator. However, the model had a narrow validation range, depending on the empirical formula, and it did not fully consider environment variables. This study presents an improved model by replacing the empirical formulae in the previous model with physical equations that take into account physical phenomena and environmental variables. During this process, additional operation parameters, such as pressure, temperature and ac waveforms, are newly taken to predict the thrust performance of the actuators with a wider range of existing parameters, the thickness of the dielectric barrier, the exposed electrode, the dielectric constant, the ac frequency and the voltage amplitude. Thrust prediction curves from the model are compared to those of earlier experimental results, showing that the average error is less than 5% for more than one hundred instances of data. As in the earlier work, the predicted thrust value is implemented on a CFD solver, and two-dimensional wall-jet velocity profiles induced by the actuator are compared to the previous experimental results.

  1. Neandertal humeri may reflect adaptation to scraping tasks, but not spear thrusting.

    Directory of Open Access Journals (Sweden)

    Colin N Shaw

    Full Text Available Unique compared with recent and prehistoric Homo sapiens, Neandertal humeri are characterised by a pronounced right-dominant bilateral strength asymmetry and an anteroposteriorly strengthened diaphyseal shape. Remodeling in response to asymmetric forces imposed during regular underhanded spear thrusting is the most influential explanatory hypothesis. The core tenet of the "Spear Thrusting Hypothesis", that underhand thrusting requires greater muscle activity on the right side of the body compared to the left, remains untested. It is unclear whether alternative subsistence behaviours, such as hide processing, might better explain this morphology. To test this, electromyography was used to measure muscle activity at the primary movers of the humerus (pectoralis major (PM, anterior (AD and posterior deltoid (PD during three distinct spear-thrusting tasks and four separate scraping tasks. Contrary to predictions, maximum muscle activity (MAX and total muscle activity (TOT were significantly higher (all values, p<.05 at the left (non-dominant AD, PD and PM compared to the right side of the body during spear thrusting tasks. Thus, the muscle activity required during underhanded spearing tasks does not lend itself to explaining the pronounced right dominant strength asymmetry found in Neandertal humeri. In contrast, during the performance of all three unimanual scraping tasks, right side MAX and TOT were significantly greater at the AD (all values, p<.01 and PM (all values, p<.02 compared to the left. The consistency of the results provides evidence that scraping activities, such as hide preparation, may be a key behaviour in determining the unusual pattern of Neandertal arm morphology. Overall, these results yield important insight into the Neandertal behavioural repertoire that aided survival throughout Pleistocene Eurasia.

  2. Effect of Functional Chewing Training on tongue thrust and drooling in children with cerebral palsy: a randomised controlled trial.

    Science.gov (United States)

    Inal, Ö; Serel Arslan, S; Demir, N; Tunca Yilmaz, Ö; Karaduman, A A

    2017-11-01

    Tongue thrust, which is an oral reflex associated with sucking behaviour, may cause problems in swallowing, speech, oro-facial development and also drooling. We aimed to examine the effect of Functional Chewing Training (FuCT) on tongue thrust and drooling in children with cerebral palsy. The study included 32 children with a mean age of 58·25 ± 9·58 months who had tongue thrust. Children were divided into two groups: the FuCT group and control group receiving classical oral motor exercises. Each group received training for 12 weeks. Oral motor assessment was performed. Chewing performance level was determined with the Karaduman Chewing Performance Scale. Tongue thrust severity was evaluated with the Tongue Thrust Rating Scale. The Drooling Severity and Frequency Scale was used to evaluate drooling severity and frequency. The evaluations were performed before and after treatment. Groups were well matched in age, gender and oral motor assessment. No significant difference was found between groups in terms of pre-treatment chewing function, tongue thrust severity, drooling severity and frequency (P > 0·05). The FuCT group showed improvement in chewing performance (P = 0·001), tongue thrust severity (P = 0·046) and drooling severity (P = 0·002), but no improvement was found in terms of drooling frequency (P = 0·082) after treatment. There was no improvement in chewing performance, tongue thrust, drooling severity and frequency in the control group. A significant difference was found between groups in favour of FuCT group in tongue thrust severity (P = 0·043). This study showed that the FuCT is an effective approach on the severity of tongue thrust and drooling in children with CP. © 2017 John Wiley & Sons Ltd.

  3. Thrust Magnitudes, Rates, and 3-Dimensional Directions Delivered in Simulated Lumbar Spine High-Velocity, Low-Amplitude Manipulation.

    Science.gov (United States)

    Owens, Edward F; Hosek, Ronald S; Mullin, Linda; Dever, Lydia; Sullivan, Stephanie G B; Russell, Brent S

    The purpose of this study was to measure faculty performance of simulated spinal manipulation on a mannequin to help identify teaching standards. We measured 3-dimensional transmitted loads using a force plate mounted in the table. Thrusts were delivered through a compliant, jointed mannequin by faculty members along predefined "listings" as taught in lumbopelvic technique courses. Eleven chiropractic faculty members participated, delivering 9 thrusts at 3 loads (light, moderate, and heavy) along 9 different prone and side-posture listings, totaling 81 thrusts per participant. Single-hand Gonstead-style thrusts had variability in magnitude across participants and loads: light thrusts averaged 365 N (95% confidence interval [CI] 327-402), moderate thrusts 454 N (421-487), and heavy thrusts 682 N (623-740). All faculty members could easily distinguish the loads within their performances, but there was some crossover of load levels between participants. Thrust rates averaged 3.55 N/ms (95% CI 3.29-3.82). The dominant vector of prone thrusts was in the z direction (vertically downward), but side-to-side and inferior-to-superior vector components occurred. Faculty member performance of simulated spinal manipulation indicated that they are able to control the thrust magnitude and rate as well as direction. In this sample, there was significant variability in peak loads between participants, which needs to be considered in student learning standards. These findings may be useful in translating the understanding of force characteristics to the technique teaching lab. Copyright © 2017. Published by Elsevier Inc.

  4. Bivergent thrust wedges surrounding oceanic island arcs: Insight from observations and sandbox models of the northeastern caribbean plate

    Science.gov (United States)

    ten Brink, U.S.; Marshak, S.; Granja, Bruna J. L.

    2009-01-01

    At several localities around the world, thrust belts have developed on both sides of oceanic island arcs (e.g., Java-Timor, Panama, Vanuatu, and the northeastern Caribbean). In these localities, the overall vergence of the backarc thrust belt is opposite to that of the forearc thrust belt. For example, in the northeastern Caribbean, a north-verging accretionary prism lies to the north of the Eastern Greater Antilles arc (Hispaniola and Puerto Rico), whereas a south-verging thrust belt called the Muertos thrust belt lies to the south. Researchers have attributed such bivergent geometry to several processes, including: reversal of subduction polarity; subduction-driven mantle flow; stress transmission across the arc; gravitational spreading of the arc; and magmatic inflation within the arc. New observations of deformational features in the Muertos thrust belt and of fault geometries produced in sandbox kinematic models, along with examination of published studies of island arcs, lead to the conclusion that the bivergence of thrusting in island arcs can develop without reversal of subduction polarity, without subarc mantle flow, and without magmatic inflation. We suggest that the Eastern Greater Antilles arc and comparable arcs are simply crustalscale bivergent (or "doubly vergent") thrust wedges formed during unidirectional subduction. Sandbox kinematic modeling suggests, in addition, that a broad retrowedge containing an imbricate fan of thrusts develops only where the arc behaves relatively rigidly. In such cases, the arc acts as a backstop that transmits compressive stress into the backarc region. Further, modeling shows that when arcs behave as rigid blocks, the strike-slip component of oblique convergence is accommodated entirely within the prowedge and the arc-the retrowedge hosts only dip-slip faulting ("frontal thrusting"). The existence of large retrowedges and the distribution of faulting in an island arc may, therefore, be evidence that the arc is

  5. Subacute effects of cervicothoracic spinal thrust/non-thrust in addition to shoulder manual therapy plus exercise intervention in individuals with subacromial impingement syndrome: a prospective, randomized controlled clinical trial pilot study.

    Science.gov (United States)

    Wright, Alexis A; Donaldson, Megan; Wassinger, Craig A; Emerson-Kavchak, Alicia J

    2017-09-01

    To determine the subacute effects of cervicothoracic spinal thrust/non-thrust in addition to shoulder non-thrust plus exercise in patients with subacromial pathology. This was a randomized, single blinded controlled trial pilot study. This trial was registered at ClinicalTrials.gov (NCT01753271) and reported according to Consolidated Standards of Reporting Trials requirements. Patients were randomly assigned to either shoulder treatment plus cervicothoracic spinal thrust/non-thrust or shoulder treatment-only group. Primary outcomes were average pain intensity (Numeric Pain Rating Scale) and physical function (Shoulder Pain and Disability Index) at 2 weeks, 4 weeks, and patient discharge. 18 patients, mean age 43.1(15.8) years satisfied the eligibility criteria and were analyzed for follow-up data. Both groups showed statistically significant improvements in both pain and function at 2 weeks, 4 weeks, and discharge. The between-group differences for changes in pain or physical function were not significant at any time point. The addition of cervicothoracic spinal thrust/non-thrust to the shoulder treatment-only group did not significantly alter improvement in pain or function in patients with subacromial pathology. Both approaches appeared to provide an equally notable benefit. Both groups improved on all outcomes and met the criteria for clinical relevance for both pain and function. 2b.

  6. Polyphase evolution of the Chaîne des Matheux frontal thrust (Haiti)

    Science.gov (United States)

    Wessels, Richard; Ellouz-Zimmermann, Nadine; Rosenberg, Claudio; Bellahsen, Nicolas; Hamon, Youri; Deschamps, Remy; Battani, Anne; Leroy, Sylvie; Momplaisir, Roberte

    2016-04-01

    The NW - SE trending Haitian fold-and-thrust belt (HFTB) is located in the western part of the Caribbean island of Hispaniola. It covers the suture between the Cretaceous Caribbean island arc in the north and the Late Cretaceous thickened oceanic crust in the south. The HFTB is bounded to the north and south by the left-lateral Septentrional (SFZ) and Enriquillo-Plantain Garden (EPGFZ) fault zones, respectively. Compressional deformation on the HFTB commenced as early as Eocene times. It was followed by transpressional deformation from the early Miocene onwards, with in sequence progressive stacking of thrust sheets towards the SW. Seismicity at the junction between the HFTB and the EPGFZ is recorded by the 12 January 2010 Mw 7.0 earthquake. Surface mapping did not reveal a rupture, as the main activity occurred on the steep NNW dipping oblique transpressional Léogâne fault, while aftershocks documented motion on a shallow SW dipping thrust segment. The structural style of deformation of the HFTB, either the stacking of thrust sheets on basement heterogeneities or basement-involved thrusting, has not been studied in detail. Also lacking are conceptual models addressing the amount of convergence between the northern and southern domains, and describing how convergence was accommodated. To address these problems we conducted a detailed fieldwork on the southernmost thrust sheet, known as the Chaîne des Matheux front. Using stratigraphy, geological mapping, cross sections, kinematic fault slip data, analysis of mineralizations and fluid inclusions, and geochemical analysis of fluid seeps, we decipher the evolution of this anticlinal structure. Stratigraphic data reveal stable Eocene platform sedimentation over the whole region, which preceded deepening of the basin throughout Oligocene and early Miocene times. A diachronous evolution is evident from the middle Miocene onwards. The NE flank displays a shallowing upwards trend and clastic sedimentation, while the

  7. Immediate changes in neck pain intensity and widespread pressure pain sensitivity in patients with bilateral chronic mechanical neck pain: a randomized controlled trial of thoracic thrust manipulation vs non-thrust mobilization.

    Science.gov (United States)

    Salom-Moreno, Jaime; Ortega-Santiago, Ricardo; Cleland, Joshua Aland; Palacios-Ceña, Maria; Truyols-Domínguez, Sebastian; Fernández-de-las-Peñas, César

    2014-06-01

    The purpose of this study was to compare the effects of thoracic thrust manipulation vs thoracic non-thrust mobilization in patients with bilateral chronic mechanical neck pain on pressure pain sensitivity and neck pain intensity. Fifty-two patients (58% were female) were randomly assigned to a thoracic spine thrust manipulation group or of thoracic non-thrust mobilization group. Pressure pain thresholds (PPTs) over C5-C6 zygapophyseal joint, second metacarpal, and tibialis anterior muscle and neck pain intensity (11-point Numerical Pain Rate Scale) were collected at baseline and 10 minutes after the intervention by an assessor blinded to group allocation. Mixed-model analyses of variance (ANOVAs) were used to examine the effects of the treatment on each outcome. The primary analysis was the group * time interaction. No significant interactions were found with the mixed-model ANOVAs for any PPT (C5-C6: P>.252; second metacarpal: P>.452; tibialis anterior: P>.273): both groups exhibited similar increases in PPT (all, Pthrust manipulation experienced a greater decrease in neck pain (between-group mean difference: 1.4; 95% confidence interval, 0.8-2.1) than did those receiving thoracic spine non-thrust mobilization (P2.1), and between-group effect size was also large (SMD = 1.3) in favor of the manipulative group. The results of this randomized clinical trial suggest that thoracic thrust manipulation and non-thrust mobilization induce similar changes in widespread PPT in individuals with mechanical neck pain; however, the changes were clinically small. We also found that thoracic thrust manipulation was more effective than thoracic non-thrust mobilization for decreasing intensity of neck pain for patients with bilateral chronic mechanical neck pain. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  8. Thrust fault growth within accretionary wedges: New Insights from 3D seismic reflection data

    Science.gov (United States)

    Orme, H.; Bell, R. E.; Jackson, C. A. L.

    2015-12-01

    The shallow parts of subduction megathrust faults are typically thought to be aseismic and incapable of propagating seismic rupture. The 2011 Tohoku-Oki earthquake, however, ruptured all the way to the trench, proving that in some locations rupture can propagate through the accretionary wedge. An improved understanding of the structural character and physical properties of accretionary wedges is therefore crucial to begin to assess why such anomalously shallow seismic rupture occurs. Despite its importance, we know surprisingly little regarding the 3D geometry and kinematics of thrust network development in accretionary prisms, largely due to a lack of 3D seismic reflection data providing high-resolution, 3D images of entire networks. Thus our current understanding is largely underpinned by observations from analogue and numerical modelling, with limited observational data from natural examples. In this contribution we use PSDM, 3D seismic reflection data from the Nankai margin (3D Muroto dataset, available from the UTIG Academic Seismic Portal, Marine Geoscience Data System) to examine how imbricate thrust fault networks evolve during accretionary wedge growth. Previous studies have reported en-echelon thrust fault geometries from the NW part of the dataset, and have related this complex structure to seamount subduction. We unravel the evolution of faults within the protothrust and imbricate thrust zones by interpreting multiple horizons across faults and measuring fault displacement and fold amplitude along-strike; by doing this, we are able to investigate the three dimensional accrual of strain. We document a number of local displacement minima along-strike of faults, suggesting that, the protothrust and imbricate thrusts developed from the linkage of smaller, previously isolated fault segments. We also demonstrate that the majority of faults grew upward from the décollement, although there is some evidence for downward fault propagation. Our observations

  9. Investigation of Pneumatic Inlet and Diffuser Blowing on a Ducted Fan Propulsor in Static Thrust Operation

    Science.gov (United States)

    Kondor, Shayne; Englar, Robert J.; Lee, Warren J.

    2003-01-01

    Tilting ducted fans present a solution for the lifting and forward flight propulsion requirements of VTOL aircraft. However, the geometry of the duct enshrouding the propeller has great a effect on the efficiency of the fan in various flight modes. Shroud geometry controls the velocity and pressure at the face of the fan, while maintaining a finite loading out at the tips of the fan blades. A duct tailored for most efficient generation of static lifting thrust will generally suffer from performance deficiencies in forward flight. The converse is true as well, leaving the designer with a difficult trade affecting the overall performance and sizing of the aircraft. Ideally, the shroud of a vertical lifting fan features a generous bell mouth inlet promoting acceleration of flow into the face of the fan, and terminating in a converging nozzle at the exit. Flow entering the inlet is accelerated into the fan by the circulation about the shroud, resulting in an overall increase in thrust compared to an open propeller operating under the same conditions . The accelerating shroud design is often employed in lifting ducted fans to benefit from the thrust augmentation; however, such shroud designs produce significant drag penalties in axial flight, thus are unsuitable for efficient forward flight applications. Decelerating, or diffusing, duct designs are employed for higher speed forward flight configurations. The lower circulation on the shroud tends to decelerate the flow into the face of the fan, which is detrimental to static thrust development; however, net thrust is developed on the shroud while the benefits of finite blade loading are retained. With judicious shroud design for intended flight speeds, a net increase in efficiency can be obtained over an open propeller. In this experiment, conducted under contract to NASA LaRC (contract NAG-1-02093) circulation control is being applied to a mildly diffusing shroud design, intended for improved forward flight performance

  10. Comparison of soft-tissue, dental, and skeletal characteristics in children with and without tongue thrusting habit

    Directory of Open Access Journals (Sweden)

    Uma B Dixit

    2013-01-01

    Full Text Available Background: Tongue thrusting habit is a condition in which the tongue makes contact with any teeth anterior to the molars during swallowing. Abnormal positioning of tongue may result in dental and skeletal abnormalities. Objective: The aim of the present study was to study and compare soft-tissue, dental, and skeletal morphologic characteristics in children with and without tongue thrusting habit. Materials and Methods: A total of 21 children with tongue thrusting habit and 21 children without any habit between age 10 and 14 years were selected for the study. Various soft-issue, dental and cephalometric parameters were measured and compared statistically. Results: Significantly, higher number of children with tongue thrusting showed lip incompetency (86% vs. 14%, mouth-breathing habit (38% vs. none, hyperactive mentalis muscle activity (24% vs. none, Open-bite (52% vs. none and lisping (86% vs. none when compared to children without tongue thrust. Children with tongue thrust showed increased upper lip thickness and proclination of maxillary incisors No differences were found in angulation of mandibular incisors, inter-premolar or inter-molar widths and all the skeletal parameters studied. Conclusions: Tongue thrust seemed to affect some of the soft-tissue and dental characteristics causing lip incompetency, mouth-breathing habit, and hyperactive mentalis muscle activity, lisping, open-bite, and proclination of maxillary incisors; however, no significant skeletal changes were observed.

  11. Static investigation of two fluidic thrust-vectoring concepts on a two-dimensional convergent-divergent nozzle

    Science.gov (United States)

    Wing, David J.

    1994-01-01

    A static investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel of two thrust-vectoring concepts which utilize fluidic mechanisms for deflecting the jet of a two-dimensional convergent-divergent nozzle. One concept involved using the Coanda effect to turn a sheet of injected secondary air along a curved sidewall flap and, through entrainment, draw the primary jet in the same direction to produce yaw thrust vectoring. The other concept involved deflecting the primary jet to produce pitch thrust vectoring by injecting secondary air through a transverse slot in the divergent flap, creating an oblique shock in the divergent channel. Utilizing the Coanda effect to produce yaw thrust vectoring was largely unsuccessful. Small vector angles were produced at low primary nozzle pressure ratios, probably because the momentum of the primary jet was low. Significant pitch thrust vector angles were produced by injecting secondary flow through a slot in the divergent flap. Thrust vector angle decreased with increasing nozzle pressure ratio but moderate levels were maintained at the highest nozzle pressure ratio tested. Thrust performance generally increased at low nozzle pressure ratios and decreased near the design pressure ratio with the addition of secondary flow.

  12. Development of High-Thrust and Double-Sided Linear Synchronous Motor Module For Liquid Crystal Display Equipment

    Institute of Scientific and Technical Information of China (English)

    Myung-jin; CHUNG; Sang-yeon; HWANG

    2010-01-01

    <正>Recently,there is an increasing requirement for controlling linear motion up to a few hundred of millimeter strokes in the area of the liquid crystal display(LCD) production equipment.The requirements of the motion system for LCD production equipment are high acceleration and high velocity with positioning accuracy.To satisfy these requirements,it has to be designed with the high-thrust force and low velocity ripple.In this work, high-thrust and double-sided linear synchronous motor (LSM)module is proposed and the developed high-thrust and double-sided LSM module is verified by performance test.

  13. Mechanical Characteristics of a Thrust Magnetic Bearing%推力轴承的力学特性

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Static and dynamic mechanical characteristics of a thrustmagnetic bearing are studied owing to the inclination of the runner disk. The application refers to a thrust magnetic bearing for a turbo-expander/compressor. The static tilt of the runner disk has remarkable influence on the mechanical characteristics of thrust magnetic bearing, it can change the static load distribution between two radial magnetic bearings and will exert violent coupling effect among a thrust magnetic bearing and two radial magnetic bearings. Such a finding can be used for the coupled electromechanical dynamics analysis of rotor system equipped with magnetic bearings.

  14. Large Thrust Trans-scale Precision Positioning Stage Based on Inertial Stick-Slip Driving

    Institute of Scientific and Technical Information of China (English)

    Li Zongwei; Zhong Bowen; Wang Zhenhua; Jin Ziqi; Sun Lining; Chen Linsen

    2015-01-01

    For the smaller thrust ,it is difficult to achieve 3D trans-scale precision positioning based on previous stick-slip driving .A large thrust trans-scale precision positioning stage is studied based on the inertial stick-slip driving .The process of the movement is divided into two steps ,i .e .,the″sliding″phase and the″stickness″phase . In the whole process ,the kinematics model of the inertial stick-slip driving is established ,and it reveals some fac-tors affecting the velocity of inertial stick-slip driving .Furthermore ,a simulation of movement is preformed by Matlab-Simulink software ,and the whole process of the inertial stick-slip driving is displayed .After one experi-mental prototype is designed ,the back and forth velocity is tested .Finally ,the simulation verifies the accuracy of the kinematics model .

  15. Thrust Vector Control of an Upper-Stage Rocket with Multiple Propellant Slosh Modes

    Directory of Open Access Journals (Sweden)

    Jaime Rubio Hervas

    2012-01-01

    Full Text Available The thrust vector control problem for an upper-stage rocket with propellant slosh dynamics is considered. The control inputs are defined by the gimbal deflection angle of a main engine and a pitching moment about the center of mass of the spacecraft. The rocket acceleration due to the main engine thrust is assumed to be large enough so that surface tension forces do not significantly affect the propellant motion during main engine burns. A multi-mass-spring model of the sloshing fuel is introduced to represent the prominent sloshing modes. A nonlinear feedback controller is designed to control the translational velocity vector and the attitude of the spacecraft, while suppressing the sloshing modes. The effectiveness of the controller is illustrated through a simulation example.

  16. Study on lift-up speed of aerodynamic compliant foil thrust bearings

    Institute of Scientific and Technical Information of China (English)

    Yang Lihua; Shi Jianhua; Liu Heng; Yu Lie

    2007-01-01

    Objective The experimental study on the lift-up speed of a new kind of compliant aerodynamic foil thrust bearings was performed on the multifunctional test rig established for testing the performances of foil gas bearings. Methods The lift-up speed of foil gas thrust bearing under given axial load was analyzed through the spectrum of axial displacement response in frequency domain. Results The test results indicated that the difference in the spectrum of axial displacement responses before and after lifting up of the rotor was obvious. After lifting up of the rotor, there were only larger components of rotation frequency and lower harmanic frequencies. If the rotor wasn't lift-up, there were also larger components of other frequencies in the spectrum. Conclusion So by analyzing the spectrum of axial displacement response, the results showed that the lift-up speed was about 1 860 rpm when the axial load was 31N.

  17. F-15B ACTIVE with thrust vectoring nozzles on test stand view from rear

    Science.gov (United States)

    1995-01-01

    This November 13, 1995, photograph of the F-15 Advanced Controls Technology for Integrated Vehicles (ACTIVE) at NASA's Dryden Flight Research Center, Edwards, California, shows the aircraft's two new Pratt & Whitney nozzles that can turn up to 20 degrees in any direction. These nozzles give the aircraft thrust control in the pitch (up and down) and yaw (left and right) directions. This will reduce drag and increase fuel economy or range as compared with conventional aerodynamic controls, which increase the retarding forces (drag) acting upon the aircraft. Ground testing of a new thrust-vectoring concept employing the nozzles took place during the first two weeks of November 1995 and went well, and flight tests began in March 1996. These tests could result in significant performance increases for military and commercial aircraft. The research program is the product of a collaborative effort by NASA, the Air Force's Wright Laboratory, Pratt & Whitney, and McDonnell Douglas Aerospace.

  18. The Effect of Additives on The Performance of HydrostaticThrust Bearings

    Directory of Open Access Journals (Sweden)

    Muhammed Abdul Sattar

    2008-01-01

    Full Text Available The paper is concerned with, the behavior of the hydrostatic thrust bearings lubricated with liquid-solid lubricants using Einstein viscosity formula, and taking into account the centrifugal force resulting from high speed. Also studied is the effect of the bearing dimensions on the pressure, flow rate, load capacity, shear stress, power consumption and stiffness. The theoretical results show an increase in load capacity by (8.3% in the presence of solid graphite particles with concentration of (16% by weight as compared with pure oil, with increasing shear stress. . In general the performance of hydrostatic thrust bearings improve for load carrying capacity, volume flow rate, pumping power subjected to centrifugal parameter (S, recess position (r1, film thickness ratio (, particle concentration (.

  19. A guidance and navigation system for continuous low thrust vehicles. M.S. Thesis

    Science.gov (United States)

    Tse, C. J. C.

    1973-01-01

    A midcourse guidance and navigation system for continuous low thrust vehicles is described. A set of orbit elements, known as the equinoctial elements, are selected as the state variables. The uncertainties are modelled statistically by random vector and stochastic processes. The motion of the vehicle and the measurements are described by nonlinear stochastic differential and difference equations respectively. A minimum time nominal trajectory is defined and the equation of motion and the measurement equation are linearized about this nominal trajectory. An exponential cost criterion is constructed and a linear feedback guidance law is derived to control the thrusting direction of the engine. Using this guidance law, the vehicle will fly in a trajectory neighboring the nominal trajectory. The extended Kalman filter is used for state estimation. Finally a short mission using this system is simulated. The results indicate that this system is very efficient for short missions.

  20. Review of the Debate and the Development of Thrust Vectoring Technology

    Institute of Scientific and Technical Information of China (English)

    BenjaminGAL-OR

    1998-01-01

    In this paper,the interesting development of the very important innovation of thrust vestoring technology in applied aerodynamics is described.In Memory of a firend.Dr.W.Herbst of MBB,Germany,the so-called father of the X-31 experimental thrust vectoring fighter,who lost his life a few years ago while piloting his private airplane.Bertrand Russel:“Men are born ignorant,not stupid-they are made stupid by education.”.Admiral Hyman Rickover:“The best engineers are those who,in addition to technical expertise,have had good training in the liberal arts and understand the world around them”。

  1. Systematic Low-Thrust Trajectory Optimization for a Multi-Rendezvous Mission using Adjoint Scaling

    CERN Document Server

    Jiang, Fanghua

    2016-01-01

    A deep-space exploration mission with low-thrust propulsion to rendezvous with multiple asteroids is investigated. Indirect methods, based on the optimal control theory, are implemented to optimize the fuel consumption. The application of indirect methods for optimizing low-thrust trajectories between two asteroids is briefly given. An effective method is proposed to provide initial guesses for transfers between close near-circular near-coplanar orbits. The conditions for optimality of a multi-asteroid rendezvous mission are determined. The intuitive method of splitting the trajectories into several legs that are solved sequentially is applied first. Then the results are patched together by a scaling method to provide a tentative guess for optimizing the whole trajectory. Numerical examples of optimizing three probe exploration sequences that contain a dozen asteroids each demonstrate the validity and efficiency of these methods.

  2. Drag/thrust analysis of jet-propelled transonic transport aircraft; definition of physical drag components

    Energy Technology Data Exchange (ETDEWEB)

    Destarac, D. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France); Van der Vooren, J. [Senior research scientist, retired, Hoekse Waard (Netherlands)

    2004-09-01

    Drag/thrust analysis of jet-propelled transonic transport aircraft on the basis of calculated viscous flow is discussed. Unique definitions for viscous drag plus wave drag and for induced drag are established. The concept of additive through flow drag is introduced. Drag/thrust bookkeeping is given attention. All drag components can be calculated in the flow region adjacent to the aircraft, where numerical accuracy is expectingly highest. Uniform handling of complex aircraft configurations is brought within reach. Near-field/far-field drag balances are exact. Computational aspects are discussed, in particular the elimination of spurious drag sources. Numerical examples are given for a wing-body and for a wing-body-pylon-nacelle configuration. In either case, the spurious drag sources are eliminated. Acceptable agreement is obtained for the total drag in the first case, and for the installation drag in the second case. Extension of the analysis presented to propeller-driven transport aircraft is straightforward. (author)

  3. Replacement of Missing Anterior Teeth in a Patient with Chronic Mouth Breathing and Tongue Thrusting

    Directory of Open Access Journals (Sweden)

    Satheesh B. Haralur

    2013-01-01

    Full Text Available The loss of anterior teeth has serious functional, esthetic disabilities, in addition to compromising the patients' quality of life. Various etiologies can be attributed to the anterior tooth loss, including trauma, caries, and periodontal diseases. The chronic mouth breathing due to nasal adenoids is known to enhance the gingival and periodontal diseases. The dental literature proves the association of nasal breathing, tongue thrusting, and anterior open bite. Arch shape and tooth position are primarily determined by the equilibrium of the forces from tongue and perioral musculature. Increased force from tongue musculature in the tongue thrusting patient leads to flaring of anterior teeth, making them susceptible for periodontal and traumatic tooth loss. Replacement of the anterior teeth in this patient will also help in restoration of anterior guidance, which is critical for the health of temporomandibular joint, posterior teeth, and musculature.

  4. Replacement of missing anterior teeth in a patient with chronic mouth breathing and tongue thrusting.

    Science.gov (United States)

    Haralur, Satheesh B; Al-Qahtani, Ali Saad

    2013-01-01

    The loss of anterior teeth has serious functional, esthetic disabilities, in addition to compromising the patients' quality of life. Various etiologies can be attributed to the anterior tooth loss, including trauma, caries, and periodontal diseases. The chronic mouth breathing due to nasal adenoids is known to enhance the gingival and periodontal diseases. The dental literature proves the association of nasal breathing, tongue thrusting, and anterior open bite. Arch shape and tooth position are primarily determined by the equilibrium of the forces from tongue and perioral musculature. Increased force from tongue musculature in the tongue thrusting patient leads to flaring of anterior teeth, making them susceptible for periodontal and traumatic tooth loss. Replacement of the anterior teeth in this patient will also help in restoration of anterior guidance, which is critical for the health of temporomandibular joint, posterior teeth, and musculature.

  5. Lyapunov-based Low-thrust Optimal Orbit Transfer: An approach in Cartesian coordinates

    CERN Document Server

    Zhang, Hantian; Cao, Qingjie

    2014-01-01

    This paper presents a simple approach to low-thrust optimal-fuel and optimal-time transfer problems between two elliptic orbits using the Cartesian coordinates system. In this case, an orbit is described by its specific angular momentum and Laplace vectors with a free injection point. Trajectory optimization with the pseudospectral method and nonlinear programming are supported by the initial guess generated from the Chang-Chichka-Marsden Lyapunov-based transfer controller. This approach successfully solves several low-thrust optimal problems. Numerical results show that the Lyapunov-based initial guess overcomes the difficulty in optimization caused by the strong oscillation of variables in the Cartesian coordinates system. Furthermore, a comparison of the results shows that obtaining the optimal transfer solution through the polynomial approximation by utilizing Cartesian coordinates is easier than using orbital elements, which normally produce strongly nonlinear equations of motion. In this paper, the Eart...

  6. State-space analysis of the dynamic characteristics of a variable thrust liquid propellant rocket engine

    Science.gov (United States)

    Zhang, Yu-Lin

    This paper states the application of state-space method to the analysis of the dynamic characteristics of a variable thrust liquid propellant rocket engine and presents a set of state equations for describing the dynamic process of the engine. An efficient numerical method for solving these system equations is developed. The theoretical solutions agree well with the experimental data. The analysis leads to the following conclusion: the set coefficient of the pulse width, the working frequency of the solenoid valves and the deviation of the critical working points of these valves are important parameters for determining the dynamic response time and the control precision of this engine. The methods developed in this paper may be used effectively in the analysis of dynamic characteristics of variable thrust liquid propellant rocket engines.

  7. Implementation of the Orbital Maneuvering Systems Engine and Thrust Vector Control for the European Service Module

    Science.gov (United States)

    Millard, Jon

    2014-01-01

    The European Space Agency (ESA) has entered into a partnership with the National Aeronautics and Space Administration (NASA) to develop and provide the Service Module (SM) for the Orion Multipurpose Crew Vehicle (MPCV) Program. The European Service Module (ESM) will provide main engine thrust by utilizing the Space Shuttle Program Orbital Maneuvering System Engine (OMS-E). Thrust Vector Control (TVC) of the OMS-E will be provided by the Orbital Maneuvering System (OMS) TVC, also used during the Space Shuttle Program. NASA will be providing the OMS-E and OMS TVC to ESA as Government Furnished Equipment (GFE) to integrate into the ESM. This presentation will describe the OMS-E and OMS TVC and discuss the implementation of the hardware for the ESM.

  8. Metrics for NASA Aeronautics Research Mission Directorate (ARMD) Strategic Thrust 3B Vertical Lift Strategic Direction

    Science.gov (United States)

    Hochstetler, Ronald D.; Salvano, Dan; Gorton, Susan A.

    2017-01-01

    The NASA Aeronautics Research Mission Directorate (ARMD) Strategic Implementation Plan details an ambitious plan for aeronautical research for the next quarter century and beyond. It includes a number of advanced technologies needed to address requirements of the overall aviation community (domestic and international), with an emphasis on safety, efficiency, operational flexibility, and alternative propulsion air transport options. The six ARMD Strategic Thrust Areas (STAs) represent a specific set of multi-decade research agendas for creating the global aviation improvements most in demand by the aviation service consumers and the general public. To provide NASA with a measurement of the preeminent value of these research areas, it was necessary to identify and quantify the measurable benefits to the aviation community from capabilities delivered by the research programs. This paper will describe the processes used and the conclusions reached in defining the principal metrics for ARMD Strategic Thrust Area 3B "Vertical Lift Strategic Direction."

  9. Thrust production and wake structure of a batoid-inspired oscillating fin

    Science.gov (United States)

    CLARK, R. P.; SMITS, A. J.

    2009-01-01

    Experiments are reported on the hydrodynamic performance of a flexible fin. The fin replicates some features of the pectoral fin of a batoid fish (such as a ray or skate) in that it is actuated in a travelling wave motion, with the amplitude of the motion increasing linearly along the span from root to tip. Thrust is found to increase with non-dimensional frequency, and an optimal oscillatory gait is identified. Power consumption measurements lead to the computation of propulsive efficiency, and an optimal efficiency condition is evaluated. Wake visualizations are presented, and a vortex model of the wake near zero net thrust is suggested. Strouhal number effects on the wake topology are also illustrated. PMID:19746188

  10. Pilot Wave Model for Impulsive Thrust from RF Test Device Measured in Vacuum

    Science.gov (United States)

    White, Harold; Lawrence, James; Sylvester, Andre; Vera, Jerry; Chap, Andrew; George, Jeff

    2017-01-01

    A physics model is developed in detail and its place in the taxonomy of ideas about the nature of the quantum vacuum is discussed. The experimental results from the recently completed vacuum test campaign evaluating the impulsive thrust performance of a tapered RF test article excited in the TM212 mode at 1,937 megahertz (MHz) are summarized. The empirical data from this campaign is compared to the predictions from the physics model tools. A discussion is provided to further elaborate on the possible implications of the proposed model if it is physically valid. Based on the correlation of analysis prediction with experimental data collected, it is proposed that the observed anomalous thrust forces are real, not due to experimental error, and are due to a new type of interaction with quantum vacuum fluctuations.

  11. Research on Design Method of the Full Form Ship with Minimum Thrust Deduction Factor

    Institute of Scientific and Technical Information of China (English)

    张宝吉; 缪爱琴; 张竹心

    2015-01-01

    In the preliminary design stage of the full form ships, in order to obtain a hull form with low resistance and maximum propulsion efficiency, an optimization design program for a full form ship with the minimum thrust deduction factor has been developed, which combined the potential flow theory and boundary layer theory with the optimization technique. In the optimization process, the Sequential Unconstrained Minimization Technique (SUMT) interior point method of Nonlinear Programming (NLP) was proposed with the minimum thrust deduction factor as the objective function. An appropriate displacement is a basic constraint condition, and the boundary layer separation is an additional one. The parameters of the hull form modification function are used as design variables. At last, the numerical optimization example for lines of after-body of 50000 DWT product oil tanker was provided, which indicated that the propulsion efficiency was improved distinctly by this optimal design method.

  12. Investigation of Thrust and Drag Characteristics of a Plug-type Exhaust Nozzle

    Science.gov (United States)

    Hearth, Donald P; Gorton, Gerald C

    1954-01-01

    An investigation was conducted in the 8- by 6-foot supersonic wind tunnel on the external and internal characteristics of a plug-type exhaust nozzle. Two positions of the center plug, one simulating a convergent nozzle and the other a convergent-divergent nozzle, were investigated. Data were obtained at free-stream Mach numbers of 0.1, 0.6, 1.6, and 2.0 over a pressure-ratio range of 1 to 20 and angles of attack of zero and 8 degrees. Results of this investigation indicated that the plug nozzle had thrust-minus-drag performance over the entire pressure-ratio range comparable with equivalent conventional nozzles. The effect of the exhaust jet on the external aerodynamics was similar to results observed for conventional nozzles. In addition, the thrust characteristics were generally insensitive to external flow and good agreement was noted with data obtained on comparable plug nozzles in quiescent air.

  13. Shallow seismic imaging of folds above the Puente Hills blind-thrust fault, Los Angeles, California

    Science.gov (United States)

    Pratt, Thomas L.; Shaw, John H.; Dolan, James F.; Christofferson, Shari A.; Williams, Robert A.; Odum, Jack K.; Plesch, Andreas

    2002-05-01

    High-resolution seismic reflection profiles image discrete folds in the shallow subsurface (Puente Hills blind-thrust fault system, Los Angeles basin, California. The profiles demonstrate late Quaternary activity at the fault tip, precisely locate the axial surfaces of folds within the upper 100 m, and constrain the geometry and kinematics of recent folding. The Santa Fe Springs segment of the Puente Hills fault zone shows an upward-narrowing kink band with an active anticlinal axial surface, consistent with fault-bend folding above an active thrust ramp. The Coyote Hills segment shows an active synclinal axial surface that coincides with the base of a 9-m-high scarp, consistent with tip-line folding or the presence of a backthrust. The seismic profiles pinpoint targets for future geologic work to constrain slip rates and ages of past events on this important fault system.

  14. What controls the growth and shape of the Himalayan foreland fold-and-thrust belt?

    Science.gov (United States)

    Grujic, Djordje; Hirschmiller, John; Mallyon, Deirdre

    2014-05-01

    We provide empirical evidence for the impact of surface processes on the structure and geometry of the present-day foreland fold-and-thrust belt (FTB) of the Himalaya. We have reconstructed and analysed ten balanced cross sections distributed along the entire length of the Himalayan arc. Here, we focus on the Siwalik Group, which represents the deformed part of the foreland basin and consists of synorogenic middle Miocene to Pleistocene sediments that form the youngest and frontal part of the Himalayan orogen. Within the active foreland fold-and-thrust belt of the Himalaya, extension, strain rate, and belt morphology vary systematically from west to east. Strain rates correlate well with west-to east increases in convergence rates according to both long-term plate velocity data and GPS data, suggesting that Pliocene to Holocene shortening is externally imposed and related to plate convergence rates. Conversely, the eastward decrease in belt width corresponds to an eastward increase in rainfall rates and specific stream power. Although mass accretion rates have not been well constrained, we argue that they remain relatively constant along the FTB. We suggest that the morphology of the Himalayan FTB is controlled primarily by erosion, in accordance with the critical taper model. Surface material removal is mainly controlled through rainfall and runoff and can be expressed as specific stream power. Thus, we propose that climatically induced erosion is the principal control on Himalayan foreland fold-and-thrust belt morphology. We test this hypothesis through a series of 1D numerical models. Among the parameters controlling the form of a wedge, lithology, erodibility, and rock mechanical properties are relatively homogeneous throughout the belt. Hence, within the range of observed values in the Himalaya, we investigate the sensitivity of the shape of the Himalayan fold-and-thrust belt to the sole-out depth of the basal décollement, flux of tectonically added material

  15. A Foil Thrust Bearing Test Rig for Evaluation of High Temperature Performance and Durability

    Science.gov (United States)

    2008-04-01

    communication faults. Test Articles Thrust runners, shown in figures 4 and 5, are rotating disks usually constructed of Inconel 718 , a nickel-based superalloy...constructed of various corrosion-resistant steels, and bearing foils are most often constructed from Inconel X750. Commercial bearings are purchased with...coatings with increased temperature capability are required for some applications. Uncoated Inconel X750 top foils run against PS304-coatings in

  16. Flow visualization and interpretation of visualization data for deflected thrust V/STOL nozzles

    Science.gov (United States)

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

    1984-01-01

    Flow visualization studies were made for four deflected thrust nozzle models at subsonic speeds. Based on topological rules and the assumption that observed streaks constitute continuous vector fields, available visualization pictures are interpreted and flow patterns on interior surfaces of the nozzles are synthesized. In particular, three dimensional flow structure and separations are discussed. From the synthesized patterns, the overall features of the flow field in a given nozzle can be approximately perceived. Previously announced in STAR as N84-14147

  17. The Role of Climate in the Deformation of a Fold and Thrust Belt

    Science.gov (United States)

    Steen, S. K.; Wiltschko, D.

    2011-12-01

    Theory and experiment show that the rate and geographic distribution of erosion control the rate and pattern of deformation in collisional mountain belts. Enhanced erosion reduces the mass of material that must be moved up and over ramps and uplifted in large folds. In order to test this and related ideas in a natural example, we have compared modeled rainfall to measured thrust sheet displacement, geometry, and internal deformation in the Appalachian fold and thrust belt. We use mean annual precipitation from a global climate model (GCM) as a proxy for rate of erosion. Deformation measurements were made on a portfolio of regional cross sections from Alabama to New England. During the Carboniferous Allegheny orogeny the Southern Appalachians moved from -30 ° to 0° latitude whereas the Central and Northern Appalachians lay between -15° and 5° latitude. Mean annual precipitation determined from the GENESIS 2 GCM (Grossman, per. comm.) varied from tropical to arid conditions as the collision both moved north and grew in breadth and height. The Southern Appalachians, which experienced more net rainfall than other regions, generally show more displacement, deeper exhumation, and shallower ramps than regions to the north. The vicinity of the Pine Mountain thrust sheet in the Southern Appalachians experienced the most displacement (~1.5X the Central Appalachians) and bulk shortening (~1.6X the Central Appalachians) and produced the most eroded material (~1.5X the Central Appalachians). The latitude of the Pine Mountain thrust sheet received ~20% more rainfall than the Central Appalachians. Although the number of regional detachments and lithologies change from Southern to Central and Northern Appalachians, the change in rainfall both regionally at any one time and as the collision progressed may explain part of the change in structural style from south to north.

  18. Structural modelling of thrust zones utilizing photogrammetry: Western Champsaur basin, SE France

    Science.gov (United States)

    Totake, Yukitsugu; Butler, Rob; Bond, Clare

    2016-04-01

    Recent advances in photogrammetric technologies allow geoscientists to easily obtain a high-resolution 3D geospatial data across multiple scales, from rock specimen to landscape. Although resolution and accuracy of photogrammetry models are dependent on various factors (a quality of photography, number of overlapping photo images, distance to targets, etc), modern photogrammetry techniques can even provide a comparable data resolution to laser scanning technologies (modelling of various geological objects. Another advantages of photogrammetry techniques, high portability and low costs for infrastructures, ease to incorporate these techniques with conventional geological surveys. Photogrammetry techniques have a great potential to enhance performances of geological surveys. We present a workflow for building basin-scale 3D structural models utilizing the ground-based photogrammetry along with field observations. The workflow is applied to model thrust zones in Eocene-Oligocene turbidite sequences called Champsaur Sandstone (Gres du Champsaur) filling an Alpine fore-deep basin, Western Champsaur basin, in southeastern France. The study area is located ca. 20km northeast from Gap, and approximately extends 10 km from east to west and 6 km from north to south. During a 2-week fieldwork, over 9400 photographs were taken at 133 locations by a handheld digital camera from ground, and were georeferenced with a handheld GPS. Photo images were processed within software PhotoScan to build a 3D photogrammetric model. The constructed photogrammetry model was then imported into software Move to map faults and geological layers along with georeferenced field data so that geological cross sections and 3D surfaces are produced. The workflow succeeded to produce a detailed topography and textures of landscape at ~1m resolution, and enabled to characterize thrust systems in the study area at bed-scale resolution. Three-dimensionally characterized architectures of thrust zones at high

  19. Minibasins and salt canopy in foreland fold-and-thrust belts: The central Sivas Basin, Turkey

    Science.gov (United States)

    Kergaravat, Charlie; Ribes, Charlotte; Legeay, Etienne; Callot, Jean-Paul; Kavak, Kaan Sevki; Ringenbach, Jean-Claude

    2016-06-01

    The Sivas Basin in the Central Anatolian Plateau (Turkey), which formed in the context of a foreland fold-and-thrust belt (FTB), exhibits a typical wall and basin (WAB) province characterized by symmetric minibasins separated by continuous steep-flanked walls and diapirs. Extensive fieldwork including regional and detailed local mapping of the contacts and margins of minibasins, and interpretation of a set of 2-D regional seismic lines, provide evidence for the development of a shallow evaporite level separating two generations of minibasins within the WAB province. Here beds of symmetric exposed minibasins along diapir flank are younger than minibasins observed over autochthonous evaporites. Laterally away from the WAB province, increase in wavelength of the tectonic structures suggests a deepening of the decollement level. We interpret that a shallower evaporite level developed in the form of an evaporite canopy, triggered by significant lateral shortening. The Upper Eocene-Lower Oligocene autochthonous Tuzhisar evaporite level was remobilized by the northward migrating sedimentary load and the tilting of the southern basin margin during propagation of the foreland fold-and-thrust belt. Asymmetric and symmetric primary minibasins were overrun by an allochthonous sheet forming a canopy. A second generation of salt withdrawal minibasins subsided into the allochthonous salt sheet. The polygonal pattern of the WAB province influences the growing fold-and-thrust belt system during the late stage of the secondary minibasins development. The Sivas FTB basin is the result of the interaction between fold-and-thrust belt propagation, evaporite remobilization, and interaction between evaporite flow and sedimentation in the minibasins.

  20. Heat transfer modeling of jet vane Thrust Vector Control (TVC) Systems

    OpenAIRE

    Dulke, Michael F.

    1987-01-01

    Approved for public release; distribution is unlimited The research presented herein, analyzes two models of a jetvane Thrust Vector Control (TVC) System. Computational modeling was accomplished using the latest version of the PHOENICS computer code, designated PHOENICS-84. The vane configurations studied, consisted of a simple wedge and a blunt bodied vane, with a leading edge radius of 1.016 mm (1/25 in.) These models were examined in a two dimensional, sonic and subsonic, cold flow f...

  1. Kinematic Evolution of the Western Pyrenees Thrust Front From Paleomagnetic Analysis on its Foreland Basin.

    Science.gov (United States)

    Almar, Y.; Beamud, E.; Muñoz, J. A.; Garcés, M.; Murelaga, X.

    2007-12-01

    The Pyrenees is a collisional orogen formed during the Alpine orogeny. Its southwestern frontal thrust was originated as a result of the Cenozoic inversion of preexisting extensional faults. The emplacement of the frontal thrust in the Western Pyrenees generated a foreland basin, which locally accumulated more than 4,500 meters of Tertiary sediments. The kinematic evolution of the Western Pyrenees thrust front is poorly constrained due to the scarcity of reliable age constraints within the Tertiary sediments. However, the good exposure conditions of syntectonic continental deposits in its foreland basin makes it an excellent scenario to carry out paleomagnetic and structural studies in order to unravel the kinematic history, geometry and evolution of the thrust front. A magnetostratigraphic composite section along the continental basin infill was sampled covering up to 3,000 m of succession. Correlation of the local magnetostratigraphy with the GPTS was helped by a new mammal fossil locality found in continental sediments and attributed to the Agenian local biozone Y (MN2D). The cronostratigraphy of the tectosedimentary units, ranging from lower Oligocene (Cr12r) to lower Miocene, provides further constraints on the timing of two main tectosedimentary events recorded as major unconformities within the basin infill. From this study, sedimentation rates have been also obtained. The analysis of several paleomagnetic sites revealed that no vertical axes rotations occurred in the Tertiary sediments regardless superimposed folding with oblique axes could be observed, and the proximity of adjacent structures as the Estella diapir and the Pamplona fault. Finally, the analysis of the anisotropy of magnetic susceptibility together with collected sedimentary data suggests that magnetic fabrics record both, a depositional and tectonic fabric.

  2. Importance of head thrust test like bedside test in ENT outpatient clinic

    Directory of Open Access Journals (Sweden)

    Batuecas-Caletrio A, Muñoz Herrera A

    2012-11-01

    Full Text Available Head thrust test is a simple test that provides great information in the studyof patients with vestibular pathology. Despite a relatively low sensitivity, thespecificity is very high so it can be helpful in diagnosing severe vestibulardeficit as in the differential diagnosis of acute vestibular disorders such asneuritis vestibular. In this paper we review the physiology vestibulooculomotorreflex, performing the test, the interpretation of the results andthe advantages of its realization

  3. The recycled orogenic sand provenance from an uplifted thrust belt, Betic Cordillera, Southern Spain

    OpenAIRE

    Critelli, Salvatore; Arribas Mocoroa, José; Le Pera, Emilia; Tortosa, A; Marsaglia, Kathleen M.; Latter, Kelly K.

    2003-01-01

    The Betic Cordillera of southern Spain represents an uplifted foreland fold–thrust belt. Source rock types of the Betic Cordillera include metamorphic (mainly phyllite, schist, quartzite, and gneiss), sedimentary (siliciclastic and carbonate), volcanic (felsic to intermediate pyroclasts), and mantle-derived (peridotite, gabbro, serpentinite, and serpentine schist) rocks. The fluvial systems range that transect the Betic Cordillera are the major detrital source of sediment ...

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

    Science.gov (United States)

    Olson, Erik L.; Cooke, Michele L.

    2005-10-01

    Three-dimensional mechanical models are used to evaluate the performance of different fault growth criteria in predicting successive growth of three échelon thrust faults similar to the segments of the Puente Hills thrust system of the Los Angeles basin, California. Four sequential Boundary Element Method models explore the growth of successive échelon faults within the system by simulating snapshots of deformation at different stages of development. These models use three criteria, (1) energy release rate, (2) strain energy density, and (3) Navier-Coulomb stress, to characterize the lateral growth of the fault system. We simulate the growth of an échelon thrust fault system to evaluate the suitability of each of these criteria for assessing fault growth. Each of these three factors predicts a portion of the incipient fault geometry (i.e. location or orientation); however, each provides different information. In each model, energy release rate along the westernmost (leading) tip of the Puente Hills thrust drops with growth of the next neighboring fault; this result supports the overall lateral development of successive échelon segments. Within each model, regions of high strain energy density and Navier-Coulomb stress envelope at least a portion of the next fault to develop, although the strain energy density has stronger correlation than Navier-Coulomb stress to the location of incipient faulting. In each model, one of the two predicted planes of maximum Navier-Coulomb stress ahead of the leading fault tip matches the strike but not the dip of the incipient fault plane recreating part of the fault orientation. The incipient fault dip is best predicted by the orientation of the strain energy density envelopes around the leading fault tip. Furthermore, the energy release rate and pattern of strain energy density can be used to characterize potential soft linkage (overlap) or hard linkage (connection) of échelon faults within the system.

  5. Effects of bite raising and occlusal awareness on tongue thrust in untreated children.

    Science.gov (United States)

    Dahan, José S; Lelong, Odette

    2003-08-01

    The purpose of this study was to determine the influence of conscious bite (occlusal awareness), with or without immediate bite raising, on tongue thrust during swallowing and speech. A total of 110 untreated children (age range, 7-12 years; mean, 9 years 8 months) were examined with various extraoral and intraoral observation tests. Subjects were divided according to sex and score on the labiolingual dysfunction index (LLDI) into high (LLDI-H) and weak (LLDI-W) dysfunction groups. A special, previously tested chocolate paste was used to map tongue and tooth contacts during task performance, including conscious bite (occlusal awareness) with and without bite raising. The bite was raised with an overlay or provisional occlusal plane placed unilaterally on the maxillary right molar. The results did not show any difference between boys and girls, but other findings were related to the LLDI score. Habitual mouth closure and swallowing without the provisional occlusal plane produced less pronounced bite contact in the LLDI-H group. Swallowing with conscious bite increased the bite contact in both groups but predominantly in the LLDI-H group. Tongue thrust reacted inversely to bite contacts: it was reduced when occlusion was perceived with and without bite raise but somewhat more with the provisional occlusal plane. The LLDI-W group was less affected. Tongue thrust was inhibited in both groups during speaking with bite raising and occlusal awareness. These results indicate that conscious bite helps to control the tongue. Slight raising of the bite increases occlusal awareness and its inhibiting effect on tongue thrust. A provisional occlusal plane or a similar overlay might be a useful adjunct in training the tongue to retrude in subjects with oral dysfunction.

  6. Geometry and Kinematics of Tumuxiuke Fold and Thrust Belt in Bachu Uplift, Tarim Basin

    Science.gov (United States)

    Song, Z.; Tang, L.

    2016-12-01

    Bachu uplift, mainly characterized by a series of out-of-sequence basement involved structures, is a large scale Cenozoic structural unit located in the west of Tarim basin. The NW-SE oriented, arc shaped Tumuxiuke fold and thrust belt (TFTB), which is roughly 200km in length, constrains the northern boundary of Bachu uplift. Based on multiple 2D seismic reflection profiles, we analysed the differences in structural styles along the strike of TFTB. It is mainly consist of several basement involved thrust faults and associated folds (or monoclines). The western segment of TFTB is characterized by a single basement involved structure; as to the middle segment, there is also backthrust branching from the main basement involved structure; in contrast, the eastern segment is consist of basement involved contractional wedge structures. According to the analysis of stratigraphy involved in deformation, fault slip and growth strata, we summarized that the TFTB mainly constructed by the compressional stress during late Miocene Himalayan orogency. Then, we analyzed the kinematics of TFTB with trishear fault propagation folding model. It is suggested that the initial fault tip that located below the basement-cover contact began to propagate during the late Miocene epoch and the propagation to slip ratio (P/S) also changes along strike. At the early stage of compression, the P/S was low and sedimentary cover mainly folded; then, the thrust faults of western segment and middle segment propagated rapidly with high P/S ratio and broke through early formed folds into Neogene strata; but in the eastern segment, the main thrust fault pinch out in the thick gypsum salt layer of middle Cambrian and the sedimentary cover decoupled from basement. About the genesis of basement-involved structures of TFTB in the intracontinent circumstance, we consider the effect of positive inversion of late Proterozoic-early Palaeozoic rift which requires further evidences.

  7. Study on seal improvement and rotor thrust control of centrifugal compressor

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fluid pressure variations due to process fluctuations or balance drum seal degradation can result in rotor thrust increasing that may jeopardize thrust bearing and compressor's reliability. Also, the leakage flow through balance drum seal can seriously affect the efficiency of compressor. A method that can improve both the efficiency and reliability of centrifugal compressor is presented. The method focused on rotor thrust control and balance drum seal upgrading. The low leakage feature of Dry-Gas-Seal(DGS), high reliability of labyrinth, and the feasibility of upgrading existing structure are taken into account at the same time to design a combined labyrinth-dry gas seal system on the balancing drum. Based on the combined seal system, a Fault Self-Recovering(FSR) system for the fault of rotor shaft displacement is introduced to assure the safety and reliability of centrifugal compressor. The modern Computational Fluid Dynamics(CFD) is used to validate this envision. The numerical result and relevant information indicate that the combined sealing system could improve the efficiency of the centrifugal compressor by about 4%.

  8. An Automatic Medium to High Fidelity Low-Thrust Global Trajectory Toolchain; EMTG-GMAT

    Science.gov (United States)

    Beeson, Ryne T.; Englander, Jacob A.; Hughes, Steven P.; Schadegg, Maximillian

    2015-01-01

    Solving the global optimization, low-thrust, multiple-flyby interplanetary trajectory problem with high-fidelity dynamical models requires an unreasonable amount of computational resources. A better approach, and one that is demonstrated in this paper, is a multi-step process whereby the solution of the aforementioned problem is solved at a lower-fidelity and this solution is used as an initial guess for a higher-fidelity solver. The framework presented in this work uses two tools developed by NASA Goddard Space Flight Center: the Evolutionary Mission Trajectory Generator (EMTG) and the General Mission Analysis Tool (GMAT). EMTG is a medium to medium-high fidelity low-thrust interplanetary global optimization solver, which now has the capability to automatically generate GMAT script files for seeding a high-fidelity solution using GMAT's local optimization capabilities. A discussion of the dynamical models as well as thruster and power modeling for both EMTG and GMAT are given in this paper. Current capabilities are demonstrated with examples that highlight the toolchains ability to efficiently solve the difficult low-thrust global optimization problem with little human intervention.

  9. A Novel Method for Vertical Acceleration Noise Suppression of a Thrust-Vectored VTOL UAV.

    Science.gov (United States)

    Li, Huanyu; Wu, Linfeng; Li, Yingjie; Li, Chunwen; Li, Hangyu

    2016-12-02

    Acceleration is of great importance in motion control for unmanned aerial vehicles (UAVs), especially during the takeoff and landing stages. However, the measured acceleration is inevitably polluted by severe noise. Therefore, a proper noise suppression procedure is required. This paper presents a novel method to reduce the noise in the measured vertical acceleration for a thrust-vectored tail-sitter vertical takeoff and landing (VTOL) UAV. In the new procedure, a Kalman filter is first applied to estimate the UAV mass by using the information in the vertical thrust and measured acceleration. The UAV mass is then used to compute an estimate of UAV vertical acceleration. The estimated acceleration is finally fused with the measured acceleration to obtain the minimum variance estimate of vertical acceleration. By doing this, the new approach incorporates the thrust information into the acceleration estimate. The method is applied to the data measured in a VTOL UAV takeoff experiment. Two other denoising approaches developed by former researchers are also tested for comparison. The results demonstrate that the new method is able to suppress the acceleration noise substantially. It also maintains the real-time performance in the final estimated acceleration, which is not seen in the former denoising approaches. The acceleration treated with the new method can be readily used in the motion control applications for UAVs to achieve improved accuracy.

  10. Stem thrust prediction model for W-K-M double wedge parallel expanding gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Eldiwany, B.; Alvarez, P.D. [Kalsi Engineering Inc., Sugar Land, TX (United States); Wolfe, K. [Electric Power Research Institute, Palo Alto, CA (United States)

    1996-12-01

    An analytical model for determining the required valve stem thrust during opening and closing strokes of W-K-M parallel expanding gate valves was developed as part of the EPRI Motor-Operated Valve Performance Prediction Methodology (EPRI MOV PPM) Program. The model was validated against measured stem thrust data obtained from in-situ testing of three W-K-M valves. Model predictions show favorable, bounding agreement with the measured data for valves with Stellite 6 hardfacing on the disks and seat rings for water flow in the preferred flow direction (gate downstream). The maximum required thrust to open and to close the valve (excluding wedging and unwedging forces) occurs at a slightly open position and not at the fully closed position. In the nonpreferred flow direction, the model shows that premature wedging can occur during {Delta}P closure strokes even when the coefficients of friction at different sliding surfaces are within the typical range. This paper summarizes the model description and comparison against test data.

  11. Optimization of residual heat removal pump axial thrust and axial bearing

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, F.

    1996-12-01

    The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies.

  12. The role of tip deflection on the thrust produced by rigid flapping fins

    Science.gov (United States)

    Huera-Huarte, Francisco; Gharib, Morteza

    2015-11-01

    It is well known that flexibility plays an important role in the propulsion performance and efficiency of oscillating fin based propulsion systems. Compliance is one of the aspects that has received more attention, as it seems to be a common feature in nature's flyers and swimmers. Active control strategies are also common in nature. We will show how by deflecting only the last 10% of length of a rigid fin, at the tip, the thrust can be changed dramatically. This can be thought as an alternative to passive flexibility for controlling very efficiently the momentum transfer in the wake and therefore the thrust generation when flapping. A series of experiments have been carried with a robotic fin that allowed the control of its flapping kinematics as well as the control of the motions of its tip independently. We will be showing situations in which the tip was kept at a certain fixed position during a power stroke, and others in which it moved either in-phase or out-of-phase with the fin. The observed thrust and wake dynamics will be discussed for all these situations. The authors would like to acknowledge the financial support provided by the Gordon and Betty Moore Foundation and by the Spanish Ministerio de Economia y competitividad (MINECO) through grant DPI2012-37904. Visiting Associate in Aerospace, California Institute of Technology.

  13. Estimability of thrusting trajectories in 3-D from a single passive sensor with unknown launch point

    Science.gov (United States)

    Yuan, Ting; Bar-Shalom, Yaakov; Willett, Peter; Ben-Dov, R.; Pollak, S.

    2013-09-01

    The problem of estimating the state of thrusting/ballistic endoatmospheric projectiles moving in 3-dimensional (3-D) space using 2-dimensional (2-D) measurements from a single passive sensor is investigated. The location of projectile's launch point (LP) is unavailable and this could significantly affect the performance of the estimation and the IPP. The LP altitude is then an unknown target parameter. The estimability is analyzed based on the Fisher Information Matrix (FIM) of the target parameter vector, comprising the initial launch (azimuth and elevation) angles, drag coefficient, thrust and the LP altitude, which determine the trajectory according to a nonlinear motion equation. The full rank of the FIM ensures that one has an estimable target parameters. The corresponding Craḿer-Rao lower bound (CRLB) quantifies the estimation performance of the estimator that is statistically efficient and can be used for IPP. In view of the inherent nonlinearity of the problem, the maximum likelihood (ML) estimate of the target parameter vector is found by using a mixed (partially grid-based) search approach. For a selected grid in the drag-coefficient-thrust-altitude subspace, the proposed parallelizable approach is shown to have reliable estimation performance and further leads to the final IPP of high accuracy.

  14. Design and implementation of an active rectangular aerostatic thrust bearing stage with electromagnetic actuators

    Institute of Scientific and Technical Information of China (English)

    MAO JunHong; LI LiChuan

    2009-01-01

    The design and implementation of an active rectangular aerostaUc thrust bearing stage with electro-magnetic actuators are presented. The stage is fundamentally precise and simple since the out-of-plane degree-of-freedoms (DOF) of a thrust air bearing are closed-loop controlled by electromagnetic actua-tors. The design is one-moving-part with mechanical symmetry, and a commercially available air bear-ing is rigidly attached to the table. The actuators are four independent coils mounted to the guiding surface of the table with iron cores, which are directly machined on the table. A bench level prototype system is developed and out-of-plane axes decoupled models of the system are derived. A control al-gorithm synthesized by arbitrarily placing closed-loop poles according to the model with air bearing dynamics neglected is implemented by C programming language running on the DOS platform. The stage is capable of vertical direction precision micro-positioning and guiding 3-DOF plane motions without limiting the working range of plane motions. Positioning accuracy of the stage no longer de-pends upon design and manufacturing of an air bearing, while passive preload of the stage for a flat film aerostatic thrust bearing is eliminated.

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

    Science.gov (United States)

    Wang, Xi-ming

    2011-01-01

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

  16. The Chevron Foil Thrust Bearing: Improved Performance Through Passive Thermal Management and Effective Lubricant Mixing

    Science.gov (United States)

    Bruckner, Robert

    2013-01-01

    An improved foil thrust bearing is described that eliminates or reduces the need for forced cooling of the bearing foils while at the same time improves the load capacity of the bearing, enhances damping, provides overload tolerance, and eliminates the high speed load capacity drop-off that plagues the current state of the art. The performance improvement demonstrated by the chevron foil thrust bearing stems from a novel trailing edge shape that splays the hot lubricant in the thin film radially, thus preventing hot lubricant carry-over into the ensuing bearing sector. Additionally, the chevron shaped trailing edge induces vortical mixing of the hot lubricant with the gas that is naturally resident within the inter-pad region of a foil thrust bearing. The elimination of hot gas carry-over in combination with the enhanced mixing has enabled a completely passive thermally managed foil bearing design. Laboratory testing at NASA has confirmed the original analysis and reduced this concept to practice.

  17. Fluid evolution at the Variscan front in the vicinity of the Aachen thrust

    Science.gov (United States)

    Sindern, S.; Meyer, F. M.; Lögering, M. J.; Kolb, J.; Vennemann, T.; Schwarzbauer, J.

    2012-01-01

    Quartz-carbonate-chlorite veins were studied in borehole samples of the RWTH-1 well in Aachen. Veins formed in Devonian rocks in the footwall of the Aachen thrust during Variscan deformation and associated fluid flow. Primary fluid inclusions indicate subsolvus unmixing of a homogenous H2O-CO2-CH4-(N2)-Na-(K)-Cl fluid into a H2O-Na-(K)-Cl solution and a vapour-rich CO2-(H2O, CH4, N2) fluid. The aqueous end-member composition resembles that of metamorphic fluids of the Variscan front zone with salinities ranging from 4 to 7% NaCl equiv. and maximum homogenisation temperatures of close to 400°C. Pressure estimates indicate a burial depth between 4,500 and 8,000 m at geothermal gradients between 50 and 75°C/26 MPa, but pressure decrease to sublithostatic conditions is also indicated, probably as a consequence of fracture opening during episodic seismic activity. A second fluid system, mainly preserved in pseudo-secondary and secondary fluid inclusions, is characterised by fluid temperatures between 200 and 250°C and salinities of Aachen thrust. A second fluid influx was introduced from formation waters in the footwall of the Aachen thrust as a consequence of progressive deformation. Mixing of the cooler and lower salinity formation water with the hot metamorphic fluid during episodic fluid trapping resulted in an evolving range of physicochemical fluid inclusion characteristics.

  18. Emergency Multiengine Aircraft System for Lateral Control Using Differential Thrust Control of Wing Engines

    Science.gov (United States)

    Burken, John J. (Inventor); Burcham, Frank W., Jr. (Inventor); Bull, John (Inventor)

    2000-01-01

    Development of an emergency flight control system is disclosed for lateral control using only differential engine thrust modulation of multiengine aircraft is currently underway. The multiengine has at least two engines laterally displaced to the left and right from the axis of the aircraft. In response to a heading angle command psi(sub c) is to be tracked. By continually sensing the heading angle psi of the aircraft and computing a heading error signal psi(sub e) as a function of the difference between the heading angle command psi(sub c) and the sensed heading angle psi, a track control signal is developed with compensation as a function of sensed bank angle phi. Bank angle rate phi, or roll rate p, yaw rate tau, and true velocity produce an aircraft thrust control signal ATC(sub psi(L,R)). The thrust control signal is differentially applied to the left and right engines, with equal amplitude and opposite sign, such that a negative sign is applied to the control signal on the side of the aircraft. A turn is required to reduce the error signal until the heading feedback reduces the error to zero.

  19. IPMC-driven thrust generation: a new conceptual design (Conference Presentation)

    Science.gov (United States)

    Olsen, Zakai; Kim, Kwang Jin

    2017-04-01

    Ionic Polymer-Metal Composites (IPMC) are highly functional actuators that find many uses in the field of soft robotics due to their low actuation voltage and ability to operate in aquatic environments. The actuation of an IPMC relies on the swelling of the negatively charged side when a potential is applied, due to the free-moving cations and water molecules migrating to that half. While this bending type actuation can be utilized to perform many tasks, it is ill suited for the primary propulsion mechanism in certain soft robotic applications. Here, a new conceptual design is presented which utilizes the bending of IPMC materials to achieve complex actuation motion in an attempt to generate a non-zero net thrust for propulsion of soft robots. The design capitalizes on advances in the manufacturing processes of electroactive polymer materials, which now allow for more complex shapes and thus new and unique modes of actuation. By utilizing the consistent bending deformation of IPMC actuators, in conjunction with carefully considered geometry, an IPMC driven body may serve as a primary mode of propulsion through a positive net thrust generation. This work consists of the initial feasibility study, concept testing, and optimization for such an actuator through computer modeling and simulation. COMSOL will be used for the finite element analysis to design the most efficient and optimized design for a positive net thrust generation. Such an IPMC design may find a great deal of applications, and the potential of future integration into other soft robotic systems is considered.

  20. Artificial equilibrium points in binary asteroid systems with continuous low-thrust

    Science.gov (United States)

    Bu, Shichao; Li, Shuang; Yang, Hongwei

    2017-08-01

    The positions and dynamical characteristics of artificial equilibrium points (AEPs) in the vicinity of a binary asteroid with continuous low-thrust are studied. The restricted ellipsoid-ellipsoid model of binary system is employed for the binary asteroid system. The positions of AEPs are obtained by this model. It is found that the set of the point L1 or L2 forms a shape of an ellipsoid while the set of the point L3 forms a shape like a "banana". The effect of the continuous low-thrust on the feasible region of motion is analyzed by zero velocity curves. Because of using the low-thrust, the unreachable region can become reachable. The linearized equations of motion are derived for stability's analysis. Based on the characteristic equation of the linearized equations, the stability conditions are derived. The stable regions of AEPs are investigated by a parametric analysis. The effect of the mass ratio and ellipsoid parameters on stable region is also discussed. The results show that the influence of the mass ratio on the stable regions is more significant than the parameters of ellipsoid.