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Sample records for technologies inertial stellar

  1. The Inertial Stellar Compass (ISC): A Multifunction, Low Power, Attitude Determination Technology Breakthrough

    Science.gov (United States)

    Bauer, Frank H. (Technical Monitor); Dennehy, Neil; Gambino, Joel; Maynard, Andrew; Brady, T.; Buckley, S.; Zinchuk, J.

    2003-01-01

    The Inertial Stellar Compass (ISC) is a miniature, low power, stellar inertial attitude determination system with an accuracy of better than 0.1 degree (1 sigma) in three axes. The ISC consumes only 3.5 Watts of power and is contained in a 2.5 kg package. With its embedded on-board processor, the ISC provides attitude quaternion information and has Lost-in-Space (LIS) initialization capability. The attitude accuracy and LIS capability are provided by combining a wide field of view Active Pixel Sensor (APS) star camera and Micro- ElectroMechanical System (MEMS) inertial sensor information in an integrated sensor system. The performance and small form factor make the ISC a useful sensor for a wide range of missions. In particular, the ISC represents an enabling, fully integrated, micro-satellite attitude determination system. Other applications include using the ISC as a single sensor solution for attitude determination on medium performance spacecraft and as a bolt on independent safe-hold sensor or coarse acquisition sensor for many other spacecraft. NASA's New Millennium Program (NMP) has selected the ISC technology for a Space Technology 6 (ST6) flight validation experiment scheduled for 2004. NMP missions, such a s ST6, are intended to validate advanced technologies that have not flown in space in order to reduce the risk associated with their infusion into future NASA missions. This paper describes the design, operation, and performance of the ISC and outlines the technology validation plan. A number of mission applications for the ISC technology are highlighted, both for the baseline ST6 ISC configuration and more ambitious applications where ISC hardware and software modifications would be required. These applications demonstrate the wide range of Space and Earth Science missions that would benefit from infusion of the ISC technology.

  2. Micro-system inertial sensing technology overview.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, James Joe

    2009-02-01

    The purpose of this report is to provide an overview of Micro-System technology as it applies to inertial sensing. Transduction methods are reviewed with capacitance and piezoresistive being the most often used in COTS Micro-electro-mechanical system (MEMS) inertial sensors. Optical transduction is the most recent transduction method having significant impact on improving sensor resolution. A few other methods are motioned which are in a R&D status to hopefully allow MEMS inertial sensors to become viable as a navigation grade sensor. The accelerometer, gyroscope and gravity gradiometer are the type of inertial sensors which are reviewed in this report. Their method of operation and a sampling of COTS sensors and grade are reviewed as well.

  3. Computer simulation technology in inertial confinement (ICF)

    Energy Technology Data Exchange (ETDEWEB)

    Yabe, Takashi (Gunma Univ., Kiryu (Japan). Faculty of Engineering)

    1994-12-01

    Recent development of computational technologies in inertial confinement fusion (ICF) is reviewed with a special emphasis on hydrodynamic simulations. The CIP method developed for ICF simulations is one of the typical examples that are used in various fields of physics such as variety of computational fluid dynamics, astrophysics, laser applications, geophysics, and so on. (author).

  4. Investigation on single-star stellar-inertial guidance principle using equivalent information compression theory

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Stellar-inertial guidance is a composite guidance technique that can effectively enhance the impact accuracy of ballistic missiles. In this paper, measurement and correction equations for a single-star stellar-inertial guidance system were developed, and a concept of equivalent information compression was presented and discussed through some propositions. With this concept, accuracies of single/double star schemes were compared, and it was shown that a single-star scheme can achieve the accuracy equivalent to a double-star scheme. This theoretically proves the feasibility of the rapid determination of the optimum stellar direction of the single-star scheme. Lastly, a compensational method to correct the guidance errors was employed when the adopted navigation star deviated from the optimum stellar direction.

  5. Stellar Interferometer Technology Experiment (SITE)

    Science.gov (United States)

    Crawley, Edward F.; Miller, David; Laskin, Robert; Shao, Michael

    1995-02-01

    The MIT Space Engineering Research Center and the Jet Propulsion Laboratory stand ready to advance science sensor technology for discrete-aperture astronomical instruments such as space-based optical interferometers. The objective of the Stellar Interferometer Technology Experiment (SITE) is to demonstrate system-level functionality of a space-based stellar interferometer through the use of enabling and enhancing Controlled-Structures Technologies (CST). SITE mounts to the Mission Peculiar Experiment Support System inside the Shuttle payload bay. Starlight, entering through two apertures, is steered to a combining plate where it is interferred. Interference requires 27 nanometer pathlength (phasing) and 0.29 archsecond wavefront-tilt (pointing) control. The resulting 15 milli-archsecond angular resolution exceeds that of current earth-orbiting telescopes while maintaining low cost by exploiting active optics and structural control technologies. With these technologies, unforeseen and time-varying disturbances can be rejected while relaxing reliance on ground alignment and calibration. SITE will reduce the risk and cost of advanced optical space systems by validating critical technologies in their operational environment. Moreover, these technologies are directly applicable to commercially driven applications such as precision matching, optical scanning, and vibration and noise control systems for the aerospace, medical, and automotive sectors. The SITE team consists of experienced university, government, and industry researchers, scientists, and engineers with extensive expertise in optical interferometry, nano-precision opto-mechanical control and spaceflight experimentation. The experience exists and the technology is mature. SITE will validate these technologies on a functioning interferometer science sensor in order to confirm definitely their readiness to be baselined for future science missions.

  6. MEMS Aluminum Nitride Technology for Inertial Sensors

    Science.gov (United States)

    Vigevani, Gabriele

    2011-12-01

    The design and fabrication of MEMS Inertial Sensors (both accelerometers and gyroscopes) made of Aluminum Nitride (AlN) is described in this dissertation. The goal of this work is to design and fabricate inertial sensors based on c-axis oriented AlN polycrystalline thin films. AlN is a post-CMOS compatible piezoelectric material widely used for acoustic resonators, such Bulk Acoustic Wave (BAW) and Lamb Wave Resonators (LWR). In this work we develop the design techniques necessary to obtain inertial sensors with AlN thin film technology. Being able to use AlN as structural material for both acoustic wave resonator and sensing elements is key to achieve the three level integration of RF-MEMS components, sensing elements and CMOS in the same chip. Using AlN as integration platform is particularly suitable for large consumer emerging markets where production costs are the major factor that determine a product success. In order to achieve a platform integration, the first part of this work focuses on the fabrication process: starting from the fabrication technology used for LWR devices, this work shows that by slightly modifying some of the fabrication steps it is possible to obtain MEMS accelerometers and gyroscopes with the same structural layers used for LWR. In the second part of this work, an extensive analysis, performed with analytical and Finite Element Models (FEM), is developed for beam and ring based structures. These models are of great importance as they provide tools to understand the physics of lateral piezoelectric beam actuation and the major limitations of this technology. Based on the models developed for beam based resonators, we propose two designs for Double Ended Tuning Fork (DETF) based accelerometers. In the last part of the dissertation, we show the experimental results and the measurements performed on actual devices. As this work shows analytically and experimentally, there are some fundamental constraints that limit the ultimate sensitivity

  7. Technology applications for Magneto Inertial Fusion

    Science.gov (United States)

    Intrator, T.; Weber, T.; Gao, K.; Yoo, C.; Klarenbeek, J.

    2012-10-01

    We describe several technology advances that we believe will be helpful for Magneto Inertial Fusion (MIF) experiments. We are developing plasma guns to improve the startup and flux trapping for magnetized plasma field reversed configuration (FRC) targets for MIF compression. This should aid initial pre ionization, freezing in of bias flux, line tie each end to the middle to retard toroidal rotation, and provide end shorting of radial electric fields. We are also developing a novel magnetic field diagnostic that uses a tiny section of Terbium doped optical fiber as a Faraday rotation medium. The optical path and hardware is inexpensive and simple, and has a small form factor that will fit inside a MagLIF capsule, and can be radation hardened. Low noise, optically coupled magnetic field measurements will be possible for vacuum MaGLIF shots.

  8. Alignment and Calibration of Optical and Inertial Sensors Using Stellar Observations

    Science.gov (United States)

    2007-01-01

    navigation error model [16]. The accelerometer and gyro- scopic bias errors were each modeled as a first-order Gauss - Markov process [10], based on the...Filtering. John Wi- ley and Sons, Inc., New York, NY, 1992. [2] Cloud Cap Technology. Crista Inertial Mea- surement Unit (IMU) Interface / Opera- tion

  9. Indoor dynamic positioning system based on strapdown inertial navigation technology

    Science.gov (United States)

    Xing, YaDong; Wu, Hong

    2011-11-01

    Strapdown inertial navigation technology, which is widely used in aerospace, is a navigation technology in which the gyros sensor and accelerometers sensor are rigidly attached to the body of the object. This article describes an application of strapdown inertial navigation technology in indoor dynamic positioning system. The hardware design of the node include the master controller, data collection, sensors, antenna and related peripheral circuit. Positioning algorithm, data acquisition and transmission are done by software programming based on the hardware circuit. The strapdown inertial navigation composed of the hardware and the software could calculate the position of the object. Simulation software(matlab) is used to confirm the correctness of the positioning algorithm which is implemented by software programming in the system. The system uses the wireless sensor network to expand the range of the positioning. The system of which the information transmission is reliable and the mobility is strongly can satisfy the requirements of the emergency.

  10. Tracking Systems and the Value of Inertial Technology

    NARCIS (Netherlands)

    Kuijper, F.; Smits, A.T.; Jense, G.J.

    1999-01-01

    This paper intents to add to the literature on 3D position and orientation tracking systems by describing TNO's experience with the InterSense tracking system that uses a combination of inertial and ultra-sound technology. From the results of a performance evaluation study and our practical

  11. Tracking Systems and the Value of Inertial Technology

    NARCIS (Netherlands)

    Kuijper, F.; Smits, A.T.; Jense, G.J.

    1999-01-01

    This paper intents to add to the literature on 3D position and orientation tracking systems by describing TNO's experience with the InterSense tracking system that uses a combination of inertial and ultra-sound technology. From the results of a performance evaluation study and our practical experien

  12. The technology benefits of inertial confinement fusion research

    Energy Technology Data Exchange (ETDEWEB)

    Powell, H T

    1999-05-26

    The development and demonstration of inertial fusion is incredibly challenging because it requires simultaneously controlling and precisely measuring parameters at extreme values in energy, space, and time. The challenges range from building megajoule (10{sup 6} J) drivers that perform with percent-level precision to fabricating targets with submicron specifications to measuring target performance at micron scale (10{sup {minus}6} m) with picosecond (10{sup {minus}12} s) time resolution. Over the past 30 years in attempting to meet this challenge, the inertial fusion community around the world has invented new technologies in lasers, particle beams, pulse power drivers, diagnostics, target fabrication, and other areas. These technologies have found applications in diverse fields of industry and science. Moreover, simply assembling the teams with the background, experience, and personal drive to meet the challenging requirements of inertial fusion has led to spin-offs in unexpected directions, for example, in laser isotope separation, extreme ultraviolet lithography for microelectronics, compact and inexpensive radars, advanced laser materials processing, and medical technology. The experience of inertial fusion research and development of spinning off technologies has not been unique to any one laboratory or country but has been similar in main research centers in the US, Europe, and Japan. Strengthening and broadening the inertial fusion effort to focus on creating a new source of electrical power (inertial fusion energy [IFE]) that is economically competitive and environmentally benign will yield rich rewards in technology spin-offs. The additional challenges presented by IFE are to make drivers affordable, efficient, and long-lived while operating at a repetition rate of a few Hertz; to make fusion targets that perform consistently at high-fusion yield; and to create target chambers that can repetitively handle greater than 100-MJ yields while producing minimal

  13. Measurements Of Stellar And Big-Bang Nucleosynthesis Reactions Using Inertially-Confined Plasmas

    Science.gov (United States)

    Zylstra, Alex; Herrmann, Hans; Gatu Johnson, Maria; Kim, Yongho; Frenje, Johan; Hale, Gerry; Li, Chikang; Rubery, Mike; Paris, Mark; Bacher, Andy; Brune, Carl; Forrest, Chad; Glebov, Vladimir; Janezic, Roger; McNabb, Dennis; Nikroo, Abbas; Pino, Jesse; Sangster, Craig; Seguin, Fredrick; Sio, Hong; Stoeckl, Christian; Petrasso, Richard

    2016-09-01

    The 3He+ 3He, T+3He, and p+D reactions directly relevant to either Stellar or Big-Bang Nucleosynthesis (BBN) have been studied at the OMEGA laser facility using inertially-confined plasmas, created using shock-driven `exploding pusher' implosions. These plasmas better mimic astrophysical systems than cold-target accelerator experiments. A new measured S-factor for the T(3He, γ)6Li reaction rules out an anomalously-high 6Li production during the Big Bang as an explanation to the high observed values in metal poor first generation stars. Our value is also inconsistent with values used in previous BBN calculations. Proton spectra from the 3He+3He and T+3He reactions are used to constrain nuclear R-matrix modeling, and recent experiments have probed the p+D reaction for the first time in a plasma. This work was partially supported by the LDRD program at LANL, US DOE, NLUF, LLE, and GA.

  14. Advances in Inertial Measurement Technology for Marine Motion Control

    Directory of Open Access Journals (Sweden)

    Mathias Håndlykken

    1996-01-01

    Full Text Available This paper describes the function of an inertial "strap down" attitude sensor based on solid state Coriolis force rate gyros, accelerometers and magnetic sensor. Performance is analyzed taking into account the typical excitations in attitude and linear motion seen in marine applications. The use is for control of fast crafts, ROV and AUV heading, roll, pitch and heave control. The influence on performance given by utilization of external information from velocity log and more accurate heading devices is also analyzed. Typical performance of this low cost type of technology is shown.

  15. Application of inertial confinement fusion to weapon technology

    Energy Technology Data Exchange (ETDEWEB)

    Toepfer, A.J.; Posey, L.D.

    1978-12-01

    This report reviews aspects of the military applications of the inertial confinement fusion (ICF) program at Sandia Laboratories. These applications exist in the areas of: (1) weapon physics research, and (2) weapon effects simulation. In the area of weapon physics research, ICF source technology can be used to study: (1) equations-of-state at high energy densities, (2) implosion dynamics, and (3) laboratory simulation of exoatmospheric burst phenomena. In the area of weapon effects simulation, ICF technology and facilities have direct near, intermediate, and far term applications. In the near term, short pulse x-ray simulation capabilities exist for electronic component effects testing. In the intermediate term, capabilities can be developed for high energy neutron exposures and bremsstrahlung x-ray exposures of components. In the far term, system level exposures of full reentry vehicles will be possible if sufficiently high pellet gains are achieved.

  16. Scientific and technological advancements in inertial fusion energy

    Science.gov (United States)

    Hinkel, D. E.

    2013-10-01

    Scientific advancements in inertial fusion energy (IFE) were reported on at the IAEA Fusion Energy Conference, October 2012. Results presented transect the different ways to assemble the fuel, different scenarios for igniting the fuel, and progress in IFE technologies. The achievements of the National Ignition Campaign within the USA, using the National Ignition Facility (NIF) to indirectly drive laser fusion, have found beneficial the achievements in other IFE arenas such as directly driven laser fusion and target fabrication. Moreover, the successes at NIF have pay-off to alternative scenarios such as fast ignition, shock ignition, and heavy-ion fusion as well as to directly driven laser fusion. This synergy is summarized here, and future scientific studies are detailed.

  17. Fusion technologies for Laser Inertial Fusion Energy (LIFE∗

    Directory of Open Access Journals (Sweden)

    Kramer K.J.

    2013-11-01

    Full Text Available The Laser Inertial Fusion-based Energy (LIFE engine design builds upon on going progress at the National Ignition Facility (NIF and offers a near-term pathway to commercial fusion. Fusion technologies that are critical to success are reflected in the design of the first wall, blanket and tritium separation subsystems. The present work describes the LIFE engine-related components and technologies. LIFE utilizes a thermally robust indirect-drive target and a chamber fill gas. Coolant selection and a large chamber solid-angle coverage provide ample tritium breeding margin and high blanket gain. Target material selection eliminates the need for aggressive chamber clearing, while enabling recycling. Demonstrated tritium separation and storage technologies limit the site tritium inventory to attractive levels. These key technologies, along with the maintenance and advanced materials qualification program have been integrated into the LIFE delivery plan. This describes the development of components and subsystems, through prototyping and integration into a First Of A Kind power plant.

  18. Chamber and target technology development for inertial fusion energy

    Energy Technology Data Exchange (ETDEWEB)

    Abdou, M; Besenbruch, G; Duke, J; Forman, L; Goodin, D; Gulec, K; Hoffer, J; Khater, H; Kulcinsky, G; Latkowski, J F; Logan, B G; Margevicious, B; Meier, W R; Moir, R W; Morley, N; Nobile, A; Payne, S; Peterson, P F; Peterson, R; Petzoldt, R; Schultz, K; Steckle, W; Sviatoslavsky, L; Tillack, M; Ying, A

    1999-04-07

    Fusion chambers and high pulse-rate target systems for inertial fusion energy (IFE) must: regenerate chamber conditions suitable for target injection, laser propagation, and ignition at rates of 5 to 10 Hz; extract fusion energy at temperatures high enough for efficient conversion to electricity; breed tritium and fuel targets with minimum tritium inventory; manufacture targets at low cost; inject those targets with sufficient accuracy for high energy gain; assure adequate lifetime of the chamber and beam interface (final optics); minimize radioactive waste levels and annual volumes; and minimize radiation releases under normal operating and accident conditions. The primary goal of the US IFE program over the next four years (Phase I) is to develop the basis for a Proof-of-Performance-level driver and target chamber called the Integrated Research Experiment (IRE). The IRE will explore beam transport and focusing through prototypical chamber environment and will intercept surrogate targets at high pulse rep-rate. The IRE will not have enough driver energy to ignite targets, and it will be a non-nuclear facility. IRE options are being developed for both heavy ion and laser driven IFE. Fig. 1 shows that Phase I is prerequisite to an IRE, and the IRE plus NIF (Phase II) is prerequisite to a high-pulse rate. Engineering Test Facility and DEMO for IFE, leading to an attractive fusion power plant. This report deals with the Phase-I R&D needs for the chamber, driver/chamber interface (i.e., magnets for accelerators and optics for lasers), target fabrication, and target injection; it is meant to be part of a more comprehensive IFE development plan which will include driver technology and target design R&D. Because of limited R&D funds, especially in Phase I, it is not possible to address the critical issues for all possible chamber and target technology options for heavy ion or laser fusion. On the other hand, there is risk in addressing only one approach to each technology

  19. AFTI/SITAN (Advanced Fighter Technology Integration/Sandia Inertial Terrain-Aided Navigation) final report

    Energy Technology Data Exchange (ETDEWEB)

    Fellerhoff, J.R.

    1988-11-01

    Sandia Inertial Terrain-Aided Navigation (SITAN) provides continuous position fixes to an inertial navigation system (INS) by real-time comparison of radar altimeter ground clearance measurements with stored digital terrain elevation data (DTED). This is accomplished by using an extended Kalman filter algorithm to estimate the errors in the reference trajectory provided by an INS. In this report, Sandia National Laboratories documents the results of a reimbursable effort funded by the Air Force Wright Aeronautical Laboratories (AFWAL) Avionics Laboratory to flight test SITAN as implemented onboard the Advanced Fighter Technology Integration (AFTI)F-16. 5 refs., 101 figs., 1 tab.

  20. Inertial Motion-Tracking Technology for Virtual 3-D

    Science.gov (United States)

    2005-01-01

    In the 1990s, NASA pioneered virtual reality research. The concept was present long before, but, prior to this, the technology did not exist to make a viable virtual reality system. Scientists had theories and ideas they knew that the concept had potential, but the computers of the 1970s and 1980s were not fast enough, sensors were heavy and cumbersome, and people had difficulty blending fluidly with the machines. Scientists at Ames Research Center built upon the research of previous decades and put the necessary technology behind them, making the theories of virtual reality a reality. Virtual reality systems depend on complex motion-tracking sensors to convey information between the user and the computer to give the user the feeling that he is operating in the real world. These motion-tracking sensors measure and report an object s position and orientation as it changes. A simple example of motion tracking would be the cursor on a computer screen moving in correspondence to the shifting of the mouse. Tracking in 3-D, necessary to create virtual reality, however, is much more complex. To be successful, the perspective of the virtual image seen on the computer must be an accurate representation of what is seen in the real world. As the user s head or camera moves, turns, or tilts, the computer-generated environment must change accordingly with no noticeable lag, jitter, or distortion. Historically, the lack of smooth and rapid tracking of the user s motion has thwarted the widespread use of immersive 3-D computer graphics. NASA uses virtual reality technology for a variety of purposes, mostly training of astronauts. The actual missions are costly and dangerous, so any opportunity the crews have to practice their maneuvering in accurate situations before the mission is valuable and instructive. For that purpose, NASA has funded a great deal of virtual reality research, and benefited from the results.

  1. Evaluation of the threshold trimming method for micro inertial fluidic switch based on electrowetting technology

    Directory of Open Access Journals (Sweden)

    Tingting Liu

    2014-03-01

    Full Text Available The switch based on electrowetting technology has the advantages of no moving part, low contact resistance, long life and adjustable acceleration threshold. The acceleration threshold of switch can be fine-tuned by adjusting the applied voltage. This paper is focused on the electrowetting properties of switch and the influence of microchannel structural parameters, applied voltage and droplet volume on acceleration threshold. In the presence of process errors of micro inertial fluidic switch and measuring errors of droplet volume, there is a deviation between test acceleration threshold and target acceleration threshold. Considering the process errors and measuring errors, worst-case analysis is used to analyze the influence of parameter tolerance on the acceleration threshold. Under worst-case condition the total acceleration threshold tolerance caused by various errors is 9.95%. The target acceleration threshold can be achieved by fine-tuning the applied voltage. The acceleration threshold trimming method of micro inertial fluidic switch is verified.

  2. Critical issues for the application of integrated MEMS/CMOS technologies to inertial measurement units

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.H.; Ellis, J.R.; Montague, S.; Allen, J.J.

    1997-03-01

    One of the principal applications of monolithically integrated micromechanical/microelectronic systems has been accelerometers for automotive applications. As integrated MEMS/CMOS technologies such as those developed by U.C. Berkeley, Analog Devices, and Sandia National Laboratories mature, additional systems for more sensitive inertial measurements will enter the commercial marketplace. In this paper, the authors will examine key technology design rules which impact the performance and cost of inertial measurement devices manufactured in integrated MEMS/CMOS technologies. These design parameters include: (1) minimum MEMS feature size, (2) minimum CMOS feature size, (3) maximum MEMS linear dimension, (4) number of mechanical MEMS layers, (5) MEMS/CMOS spacing. In particular, the embedded approach to integration developed at Sandia will be examined in the context of these technology features. Presently, this technology offers MEMS feature sizes as small as 1 {micro}m, CMOS critical dimensions of 1.25 {micro}m, MEMS linear dimensions of 1,000 {micro}m, a single mechanical level of polysilicon, and a 100 {micro}m space between MEMS and CMOS. This is applicable to modern precision guided munitions.

  3. Critical issues for the application of integrated MEMS/CMOS technologies to inertial measurement units

    Science.gov (United States)

    Smith, James H.; Montague, Stephen; Allen, James J.; Ellis, J. R.; Burgett, Scott M.

    1997-06-01

    One of the principal applications of monolithically integrated micromechanical/microelectronic systems has been accelerometers for automotive applications. As integrated MEMS/CMOS technologies such as those developed by U.C. Berkeley, Analog Devices, and Sandia National Laboratories mature, additional systems for more sensitive inertial measurements will enter the commercial marketplace. In this paper, we will examine the key technology design rules which impact the performance and cost of inertial measurement devices manufactured in integrated MEMS/CMOS technologies. These design parameters include: (1) Minimum MEMS feature size, (2) Minimum CMOS feature size, (3) Maximum MEMS linear dimension, (4) Number of mechanical MEMS layers, and (5) MEMS/CMOS spacing. In particular, the embedded approach to integration developed at Sandia will be examined in the context of these technology features. Presently, this technology offers MEMS feature sizes as small as 1 micrometers , CMOS critical dimensions of 1.25 micrometers , MEMS linear dimensions of 1000 micrometers , a single mechanical level of polysilicon, and a 100 micrometers space between MEMS and CMOS.

  4. MEMS and FOG Technologies for Tactical and Navigation Grade Inertial Sensors—Recent Improvements and Comparison

    Directory of Open Access Journals (Sweden)

    Olaf Deppe

    2017-03-01

    Full Text Available In the following paper, we present an industry perspective of inertial sensors for navigation purposes driven by applications and customer needs. Microelectromechanical system (MEMS inertial sensors have revolutionized consumer, automotive, and industrial applications and they have started to fulfill the high end tactical grade performance requirements of hybrid navigation systems on a series production scale. The Fiber Optic Gyroscope (FOG technology, on the other hand, is further pushed into the near navigation grade performance region and beyond. Each technology has its special pros and cons making it more or less suitable for specific applications. In our overview paper, we present latest improvements at NG LITEF in tactical and navigation grade MEMS accelerometers, MEMS gyroscopes, and Fiber Optic Gyroscopes, based on our long-term experience in the field. We demonstrate how accelerometer performance has improved by switching from wet etching to deep reactive ion etching (DRIE technology. For MEMS gyroscopes, we show that better than 1°/h series production devices are within reach, and for FOGs we present how limitations in noise performance were overcome by signal processing. The paper also intends a comparison of the different technologies, emphasizing suitability for different navigation applications, thus providing guidance to system engineers.

  5. MEMS and FOG Technologies for Tactical and Navigation Grade Inertial Sensors-Recent Improvements and Comparison.

    Science.gov (United States)

    Deppe, Olaf; Dorner, Georg; König, Stefan; Martin, Tim; Voigt, Sven; Zimmermann, Steffen

    2017-03-11

    In the following paper, we present an industry perspective of inertial sensors for navigation purposes driven by applications and customer needs. Microelectromechanical system (MEMS) inertial sensors have revolutionized consumer, automotive, and industrial applications and they have started to fulfill the high end tactical grade performance requirements of hybrid navigation systems on a series production scale. The Fiber Optic Gyroscope (FOG) technology, on the other hand, is further pushed into the near navigation grade performance region and beyond. Each technology has its special pros and cons making it more or less suitable for specific applications. In our overview paper, we present latest improvements at NG LITEF in tactical and navigation grade MEMS accelerometers, MEMS gyroscopes, and Fiber Optic Gyroscopes, based on our long-term experience in the field. We demonstrate how accelerometer performance has improved by switching from wet etching to deep reactive ion etching (DRIE) technology. For MEMS gyroscopes, we show that better than 1°/h series production devices are within reach, and for FOGs we present how limitations in noise performance were overcome by signal processing. The paper also intends a comparison of the different technologies, emphasizing suitability for different navigation applications, thus providing guidance to system engineers.

  6. MEMS and FOG Technologies for Tactical and Navigation Grade Inertial Sensors—Recent Improvements and Comparison

    Science.gov (United States)

    Deppe, Olaf; Dorner, Georg; König, Stefan; Martin, Tim; Voigt, Sven; Zimmermann, Steffen

    2017-01-01

    In the following paper, we present an industry perspective of inertial sensors for navigation purposes driven by applications and customer needs. Microelectromechanical system (MEMS) inertial sensors have revolutionized consumer, automotive, and industrial applications and they have started to fulfill the high end tactical grade performance requirements of hybrid navigation systems on a series production scale. The Fiber Optic Gyroscope (FOG) technology, on the other hand, is further pushed into the near navigation grade performance region and beyond. Each technology has its special pros and cons making it more or less suitable for specific applications. In our overview paper, we present latest improvements at NG LITEF in tactical and navigation grade MEMS accelerometers, MEMS gyroscopes, and Fiber Optic Gyroscopes, based on our long-term experience in the field. We demonstrate how accelerometer performance has improved by switching from wet etching to deep reactive ion etching (DRIE) technology. For MEMS gyroscopes, we show that better than 1°/h series production devices are within reach, and for FOGs we present how limitations in noise performance were overcome by signal processing. The paper also intends a comparison of the different technologies, emphasizing suitability for different navigation applications, thus providing guidance to system engineers. PMID:28287483

  7. 惯性技术的研究现状与发展趋势分析%Research Status and Development Trend Analysis of Inertial Technology

    Institute of Scientific and Technical Information of China (English)

    江嘉宇

    2015-01-01

    Inertial technology is a comprehensive subject motion information and perception technology, the core and development of inertial technology is inertial navigation technology, this paper mainly focuses on the research status and development trend of inertial technology.%惯性技术是一种综合学科运动信息感知技术,惯性技术的核心和发展标志就是惯性导航技术,本文主要针对惯性技术的研究现状与发展趋势进行综合性分析。

  8. MEMS惯性技术的发展及应用%Evolution and application of MEMS inertial technology

    Institute of Scientific and Technical Information of China (English)

    齐广峰; 吕军锋

    2015-01-01

    Micro Electro Mechanical Systems (MEMS) has become a research hotspot of the tactical inertial navigation, and one of the main research directions for future inertial navigation technology. This survey is conducted for the development and application of MEMS inertial navigation. A brief introduction of MEMS inertial sensors is first given, also the development of MEMS inertial system is introduced by the research program of Draper laboratory, then the latest developments of MEMS inertial measurement unit (IMU) and MEMS integrated navigation system has been surveyed, at last the development trend of MEMS inertial system has been summarized. High-performance MEMS gyros, chip scale MEMS-IMU and MEMS integrated system is the development trend of the MEMS inertial technology.%MEMS惯性技术是近年来战术级惯性导航的研究热点,也是惯性导航技术未来的主要发展方向之一。本文介绍了MEMS惯性传感器的发展概况,结合Draper实验室的MEMS惯性系统项目计划介绍了MEMS惯性系统的发展,分别介绍了MEMS惯性测量单元和MEMS组合导航技术的最新进展,并展望了MEMS惯性系统的发展趋势。高性能MEMS陀螺、芯片级MEMS-IMU和MEMS组合导航系统是MEMS惯性技术未来的发展趋势。

  9. Inertial Sensor Technology for Elite Swimming Performance Analysis: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Robert Mooney

    2015-12-01

    Full Text Available Technical evaluation of swimming performance is an essential factor of elite athletic preparation. Novel methods of analysis, incorporating body worn inertial sensors (i.e., Microelectromechanical systems, or MEMS, accelerometers and gyroscopes, have received much attention recently from both research and commercial communities as an alternative to video-based approaches. This technology may allow for improved analysis of stroke mechanics, race performance and energy expenditure, as well as real-time feedback to the coach, potentially enabling more efficient, competitive and quantitative coaching. The aim of this paper is to provide a systematic review of the literature related to the use of inertial sensors for the technical analysis of swimming performance. This paper focuses on providing an evaluation of the accuracy of different feature detection algorithms described in the literature for the analysis of different phases of swimming, specifically starts, turns and free-swimming. The consequences associated with different sensor attachment locations are also considered for both single and multiple sensor configurations. Additional information such as this should help practitioners to select the most appropriate systems and methods for extracting the key performance related parameters that are important to them for analysing their swimmers’ performance and may serve to inform both applied and research practices.

  10. The Indoor Personnel Inertial Positioning Based on Image Recognition Technology in Substation Depth

    Directory of Open Access Journals (Sweden)

    Xu Min

    2017-01-01

    Full Text Available A kind of inertial positioning technology personnel indoor substation depth based on image recognition, scene modeling using 3D scanning depth camera for image acquisition of fast; key position of image recognition front-end uses image recognition software algorithm, the image information is converted to dot matrix data, connect the background server to obtain accurate positioning coordinates, greatly reduce the direct image transmission to the identification of the amount of data in the deployment of additional equipment to achieve precise positioning of field personnel without the aid, effectively solve the traditional Bluetooth, millimeter wave and laser positioning need in the site layout a lot of equipment problems, eliminate safety hazards in the substation; finally, the inertial navigation algorithm, field personnel positioning using gyroscope and accelerometer do the positioning of the auxiliary, smooth, real-time and accurate, have The utility model solves the problem of poor positioning accuracy of the electric field operation, and improves the working efficiency of the field operators.

  11. HELIAS stellarator reactor studies and related European technology studies

    Energy Technology Data Exchange (ETDEWEB)

    Grieger, G. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany)); Nuehrenberg, J. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany)); Renner, H. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany)); Sapper, J. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany)); Wobig, H. (Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-85748 Garching (Germany))

    1994-08-01

    Research on stellarators has been carried out in Europe since the early years of the fusion programme. Early studies of this reactor concept were done at the Culham Laboratory of the UK Atomic Energy Authority. Such classical stellarators, however, have poor reactor prospects in spite of the significant advantage of not needing a large toroidal plasma current. It seemed to be just this large toroidal plasma current which has led to intrinsic deficiencies with respect to reactor potential of the tokamak. Expecting that these deficiencies would disappear for a concept without such a current, the Institut fuer Plasmaphysik developed, in a roll-back fashion, i.e. by starting from reactor considerations, the concept of the helical axis advanced stellarator (HELIAS). The results achieved look very promising indeed. Since tokamaks and stellarators show many similarities, there appeared no need as yet for a new stand-alone stellarator reactor study. The work was rather concentrated on the few but decisive differences between the two concepts and on evaluation of their relative importance. Studies on the coil system, the stress distribution in the supporting material, the space needed for an efficient blanket system, the properties of the exhaust system, etc. have been done. Applying contemporary scaling laws, it turns out that although the aspect ratio of such advanced stellarators is larger than that of tokamaks, the plasma volume is about the same. The magnetic energy needed for plasma confinement is considerably lower and the mass utilization tends to be larger than for comparable tokamaks. It also follows that a number of reactor components needed for tokamak operation (e.g. current drive, feedback stabilization, disruption prevention) are not needed in stellarators, making this type of reactor and its operation simpler. Such results would have a large influence on selection of the final concept and the further evolution of the fusion programme.

  12. MEMS and FOG Technologies for Tactical and Navigation Grade Inertial Sensors—Recent Improvements and Comparison

    National Research Council Canada - National Science Library

    Olaf Deppe; Georg Dorner; Stefan König; Tim Martin; Sven Voigt; Steffen Zimmermann

    2017-01-01

    .... Microelectromechanical system (MEMS) inertial sensors have revolutionized consumer, automotive, and industrial applications and they have started to fulfill the high end tactical grade performance requirements of hybrid navigation...

  13. Science and Technology Progress at the Sydney University Stellar Interferometer

    CERN Document Server

    Robertson, J Gordon; Tango, William J; Tuthill, Peter G; Warrington, Benjamin A; Kok, Yitping; Rizzuto, Aaron C; Cheetham, Anthony; Jacob, Andrew P

    2013-01-01

    This paper presents an overview of recent progress at the Sydney University Stellar Interferometer (SUSI). Development of the third-generation PAVO beam combiner has continued. The MUSCA beam combiner for high-precision differential astrometry using visible light phase referencing is under active development and will be the subject of a separate paper. Because SUSI was one of the pioneering interferometric instruments, some of its original systems are old and have become difficult to maintain. We are undertaking a campaign of modernization of systems: (1) an upgrade of the Optical Path Length Compensator IR laser metrology counter electronics from a custom system which uses an obsolete single-board computer to a modern one based on an FPGA interfaced to a Linux computer - in addition to improving maintainability, this upgrade should allow smoother motion and higher carriage speeds; (2) the replacement of the aged single-board computer local controllers for the siderostats and the longitudinal dispersion compe...

  14. 舰艇惯性导航技术现状及发展趋势%Status Quo and Trends of Marine Inertial Navigation Technology

    Institute of Scientific and Technical Information of China (English)

    刘飞; 马林

    2011-01-01

    讲述了国内外海军舰艇用惯性导航技术的现状,分析并预测了发展趋势.简述了“舰艇用惯性导航技术”的技术特点和使用需求特点,从惯性敏感器技术和系统技术两个方面对“惯性导航系统”产品进行了分类.通过阐述技术特点与不同使用需求之间的对应关系,探寻技术发展方向;并以国内外舰艇惯性导航技术发展的历程进行佐证.%The status of domestic and overseas marine inertial navigation technology is introduced and the development trends of the technology are analyzed and forecasted, the characteristics and requirements in the use of marine inertial navigation technology are described. The productions of inertial navigation system are classified from inertial sensors technology and inertial navigation system technology. The correct development direction is selected by means of exactly grasping the characteristic of technology and the corresponding connection of the different requirements. The directions of development are clarified by retrospect of the development course of marine inertial navigation technology.

  15. Wireless navigation inertial sensors on a single chip with bluetooth technology

    Science.gov (United States)

    Varadan, Vijay K.; Jose, K. A.

    2001-11-01

    The inertial navigation system uses both gyroscopes and accelerometers to measure the state of motion of a target or a vehicle by sensing the changes in that state caused by accelerations. The required features in many of these applications are high precision, wide dynamic range and wide frequency range. In this paper, recent advances made on Wireless MEMS-IDT based accelerometers and gyroscopes are presented. The concept and design principles underlying a MEMS-IDT (Interdigital Transducer) based accelerometer and gyroscope are based on using surface acoustic waves (SAW) and polysilicon seismic mass for acceleration and proff mass for gyro. This unique concept is a departure from the conventional comb driven MEMS accelerometer design. By designing the seismic mass of the accelerometer to float just above a high frequency Rayleigh Surface Acoustic Wave Sensor (SAWS), we are able to realize the accuracy and versatility required for the measurement of accelerations from 10-6g to 100g. The gyro design is based on the combination of Surface Acoustic Wave Resonator (SAWR) and Surface Acoustic Wave Sensor, which operates at the Rayleigh mode. They possess typical advantages of MEMS sensors including the additional benefits of robustness, excellent sensitivity (about 1 deg./hr.), surface conformability and durability. The transmitter IDT creates SAW (Surface Acoustic Wave) that propagates back and forth between the reflectors and forms a standing wave pattern within the cavity space between the IDTs. The particles at the anti- nodes of standing wave pattern experience large amplitude of vibration perpendicular to the plane of the substrate, which serves as the reference vibrating motion for this gyroscope. A number of metallic (proof) masses are strategically positioned at the anti-node locations so that the effect of the Coriolis force can be used to sense the gyroscopic motion. Another unique feature of the device is that because the SAW device operates at RF frequencies

  16. Upper Limb Portable Motion Analysis System Based on Inertial Technology for Neurorehabilitation Purposes

    Directory of Open Access Journals (Sweden)

    Enrique J. Gómez

    2010-12-01

    Full Text Available Here an inertial sensor-based monitoring system for measuring and analyzing upper limb movements is presented. The final goal is the integration of this motion-tracking device within a portable rehabilitation system for brain injury patients. A set of four inertial sensors mounted on a special garment worn by the patient provides the quaternions representing the patient upper limb’s orientation in space. A kinematic model is built to estimate 3D upper limb motion for accurate therapeutic evaluation. The human upper limb is represented as a kinematic chain of rigid bodies with three joints and six degrees of freedom. Validation of the system has been performed by co-registration of movements with a commercial optoelectronic tracking system. Successful results are shown that exhibit a high correlation among signals provided by both devices and obtained at the Institut Guttmann Neurorehabilitation Hospital.

  17. Inertial confinement fusion target component fabrication and technology development support: Annual report, October 1, 1995--September 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, M. [ed.

    1997-02-01

    On December 30, 1990, the U.S. Department of Energy entered into a contract with General Atomics (GA) to be the Inertial Confinement Fusion (ICF) Target Component Fabrication and Technology Development Support contractor. In September 1995 this contract ended and a second contract was issued for us to continue this ICF target support work. This report documents the technical activities of the period October 1, 1995 through September 30, 1996. During this period, GA and our partners WJ Schafer Associates (WJSA) and Soane Technologies, Inc. (STI) were assigned 14 formal tasks in support of the Inertial Confinement Fusion program and its five laboratories. A portion of the effort on these tasks included providing direct {open_quotes}Onsite Support{close_quotes} at Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), and Sandia National Laboratory Albuquerque (SNLA). We fabricated and delivered over 800 gold-plated hohlraum mandrels to LLNL, LANL and SNLA. We produced nearly 1,200 glass and plastic target capsules for LLNL, LANL, SNLA and University of Rochester/Laboratory for Laser Energetics (UR/LLE). We also delivered over 100 flat foil targets for Naval Research Lab (NRL) and SNLA in FY96. This report describes these target fabrication activities and the target fabrication and characterization development activities that made the deliveries possible. The ICF program is anticipating experiments at the OMEGA laser and the National Ignition Facility (NIF) which will require capsules containing cryogenic layered D{sub 2} or deuterium-tritium (DT) fuel. We are part of the National Cryogenic Target Program to create and demonstrate viable ways to generate and characterize cryogenic layers. Substantial progress has been made on ways to both create and characterize viable layers. During FY96, significant progress was made in the design of the OMEGA Cryogenic Target System that will field cryogenic targets on OMEGA.

  18. 船舶惯性导航技术应用与展望%Application and prospect of ship inertial navigation technology

    Institute of Scientific and Technical Information of China (English)

    张崇猛; 蔡智渊; 舒东亮; 侯巍

    2012-01-01

    以惯性导航技术的发展历程为基础,结合相关文献资料,简述了各类惯性导航器件的工作原理,综合阐述了国内外船舶惯性导航技术的发展水平和应用概况,并对国内外发展应用情况进行了比较分析,对未来船舶惯性导航技术及其系统技术的发展进行了展望,对船舶惯性导航技术的发展方向提出了看法.%This paper is based on development history of inertia navigation technique, according to related literature, describes all kinds of inertial navigation sensor principle of work, comprehensive elaboration the development level of general application of the ship inertial navigation technology at home and abroad, and to contrast the development situation of the domestic and foreign, look forward the future of ship inertial navigation technology, and puts forward some opinions on the developing direction to the ship inertial navigation technology.

  19. Technology research for strapdown inertial experiment and digital flight control and guidance

    Science.gov (United States)

    Carestia, R. A.; Cottrell, D. E.

    1985-01-01

    A helicopter flight-test program to evaluate the performance of Honeywell's Tetrad - a strapdown, laser gyro, inertial navitation system is discussed. The results of 34 flights showed a mean final navigational velocity error of 5.06 knots, with a standard deviation of 3.84 knots; a corresponding mean final position error of 2.66 n.mi., with a standard deviation of 1.48 n.m.; and a modeled mean-position-error growth rate for the 34 tests of 1.96 knots, with a standard deviation of 1.09 knots. Tetrad's four-ring laser gyros provided reliable and accurate angular rate sensing during the test program and on sensor failures were detected during the evaluation. Criteria suitable for investigating cockpit systems in rotorcraft were developed. This criteria led to the development of two basic simulators. The first was a standard simulator which could be used to obtain baseline information for studying pilot workload and interactions. The second was an advanced simulator which integrated the RODAAS developed by Honeywell into this simulator. The second area also included surveying the aerospace industry to determine the level of use and impact of microcomputers and related components on avionics systems.

  20. Inertial confinement fusion target component fabrication and technology development support: Annual report, October 1, 1993--September 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, M. [ed.

    1995-04-01

    On December 30, 1990, the US Department of Energy entered into a contract with General Atomics (GA) to be the Inertial Confinement Fusion (ICF) Target Component Fabrication and Technology Development Support contractor. During the period, GA was assigned 17 tasks in support of the Inertial Confinement Fusion program and its laboratories. This year they achieved full production capabilities for the micromachining, dimensional characterization and gold plating of hohlraums. They fabricated and delivered 726 gold-plated mandrels of 27 different types to LLNL and 48 gold-plated mandrels of two different types to LANL. They achieved full production capabilities in composite capsule production ad delivered in excess of 240 composite capsules. They continuously work to improve performance and capabilities. They were also directed to dismantle, remove, and disposition all equipment at the previous contractor (KMSF) that had radioactive contamination levels low enough that they could be exposed to the general public without radiological constraints. GA was also directed to receive and store the tritium fill equipment. They assisted LANL in the development of techniques for characterization of opaque targets. They developed deuterated and UV-opaque polymers for use by the University of Rochester`s Laboratory for Laser Energetics (UR/LLE) and devised a triple-orifice droplet generator to demonstrate the controlled-mass nature of the microencapsulation process. The ICF program is anticipating experiments at NIF and the Omega Upgrade. Both facilities will require capsules containing layered D{sub 2} or D-T fuel. They continued engineering and assembly of equipment for a cryogenic target handling system for UR/LLE that will fill, transport, layer, and characterize targets filled with cryogenic deuterium or deuterium-tritium fuel, and insert these cryogenic targets into the OMEGA Upgrade target chamber for laser implosion experiments.

  1. Inertial Confinement Fusion Target Component Fabrication and Technology Development report. Annual report, October 1, 1992--September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Steinman, D. [ed.

    1994-03-01

    On December 30, 1990, the US Department of Energy entered into a contract with General Atomics (GA) to be the Inertial Confinement Fusion Target Component Fabrication and Technology Development Support contractor. This report documents the technical activities which took place under this contract during the period of October 1, 1992 through September 30, 1993. During this period, GA was assigned 18 tasks in support of the Inertial Confinement Fusion program and its laboratories. These tasks included ``Capabilities Activation`` and ``Capabilities Demonstration`` to enable us to begin production of glass and composite polymer capsules. Capsule delivery tasks included ``Small Glass Shell Deliveries`` and ``Composite Polymer Capsules`` for Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL). We also were asked to provide direct ``Onsite Support`` at LLNL and LANL. We continued planning for the transfer of ``Micromachining Equipment from Rocky Flats`` and established ``Target Component Micromachining and Electroplating Facilities`` at GA. We fabricated over 1100 films and filters of 11 types for Sandia National Laboratory and provided full-time onsite engineering support for target fabrication and characterization. We initiated development of methods to make targets for the Naval Research Laboratory. We investigated spherical interferometry, built an automated capsule sorter, and developed an apparatus for calorimetric measurement of fuel fill for LLNL. We assisted LANL in the ``Characterization of Opaque b-Layered Targets.`` We developed deuterated and UV-opaque polymers for use by the University of Rochester`s Laboratory for Laser Energetics (UR/LLE) and devised a triple-orifice droplet generator to demonstrate the controlled-mass nature of the microencapsulation process.

  2. Magnetohydrodynamic inertial reference system

    Science.gov (United States)

    Eckelkamp-Baker, Dan; Sebesta, Henry R.; Burkhard, Kevin

    2000-07-01

    Optical platforms increasingly require attitude knowledge and optical instrument pointing at sub-microradian accuracy. No low-cost commercial system exists to provide this level of accuracy for guidance, navigation, and control. The need for small, inexpensive inertial sensors, which may be employed in pointing control systems that are required to satisfy angular line-of-sight stabilization jitter error budgets to levels of 1-3 microradian rms and less, has existed for at least two decades. Innovations and evolutions in small, low-noise inertial angular motion sensor technology and advances in the applications of the global positioning system have converged to allow improvement in acquisition, tracking and pointing solutions for a wide variety of payloads. We are developing a small, inexpensive, and high-performance inertial attitude reference system that uses our innovative magnetohydrodynamic angular rate sensor technology.

  3. Inertial Navigation Technology Introduction and Application Development Study%惯性导航技术介绍及应用发展研究

    Institute of Scientific and Technical Information of China (English)

    谭鹏辉

    2016-01-01

    本文阐述了惯性导航技术的基本原理和分类,介绍了惯性导航的核心部件陀螺仪的发展状况,并列举出代表当前最高技术水平的新型惯性器件。同时,概括了惯性技术的应用领域,并针对其优缺点介绍了一种组合导航的方式。最后指出,随着市场及实际应用的需求,未来导航系统的主要发展方向将向以惯性导航为基础的组合导航靠拢。%This paper describes the basic principles and classification of inertial navigation technology, it introduces the development of the core components of inertial navigation gyroscopes, and outlines the current representative of the highest technical level of new inertial device. It summarizes the applications of inertial technology, and introduces a combination of navigation mode for their advantages and disadvantages. Finally, with the market demand and the practical application, the main direction of the future development of the navigation system will be based on the combine navigation.

  4. Inertial squirmer

    Science.gov (United States)

    Wang, S.; Ardekani, A.

    2012-10-01

    Although the propulsion of micro-organisms has been extensively studied in the literature, current studies have mainly focused on their propulsion in the absence of inertia. Here in this paper, we quantify the effects of convective inertial forces in the limit of small, but nonzero, Reynolds number regime. We analytically quantify the role of inertia on swimming speed, energy expenditure, and flow signature of an archetypal swimming model "squirmer". Our results suggest that pushers, generating thrust behind their body, have a competitive advantage in swimming due to higher motility in the inertial regime. In contrast, those organisms that generate thrust in front of their body, pullers, have more efficient foraging in the inertial regime compared to their counterparts in the Stokes regime. Inertia enhances the swimming speed of a pusher swimmer and hinders it for a puller, potentially affecting a broad range of abundant millimeter- to centimeter-size organisms living in oceans and lakes.

  5. Micromachined Fluid Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Shiqiang Liu

    2017-02-01

    Full Text Available Micromachined fluid inertial sensors are an important class of inertial sensors, which mainly includes thermal accelerometers and fluid gyroscopes, which have now been developed since the end of the last century for about 20 years. Compared with conventional silicon or quartz inertial sensors, the fluid inertial sensors use a fluid instead of a solid proof mass as the moving and sensitive element, and thus offer advantages of simple structures, low cost, high shock resistance, and large measurement ranges while the sensitivity and bandwidth are not competitive. Many studies and various designs have been reported in the past two decades. This review firstly introduces the working principles of fluid inertial sensors, followed by the relevant research developments. The micromachined thermal accelerometers based on thermal convection have developed maturely and become commercialized. However, the micromachined fluid gyroscopes, which are based on jet flow or thermal flow, are less mature. The key issues and technologies of the thermal accelerometers, mainly including bandwidth, temperature compensation, monolithic integration of tri-axis accelerometers and strategies for high production yields are also summarized and discussed. For the micromachined fluid gyroscopes, improving integration and sensitivity, reducing thermal errors and cross coupling errors are the issues of most concern.

  6. Performance Evaluation Criteria and Analysis of Navigation Systems Using Inertial Measurement Unit Technology

    Science.gov (United States)

    2014-06-26

    level. The strapdown IMU mechanization relies on microelectromechanical systems ( MEMS ) technology for the accelerometer and gyroscope triads. The...every system, the outputs of the single-axis sensors that make up the accelerometer and gyroscope are used in conjunction with the navigation system...triads are stationary with respect to the IMU case; thus, the attitude is dead-reckoned numerically using the gyroscope data to provide the vehicle

  7. Automatic evaluation of the 30-s chair stand test using inertial/magnetic-based technology in an older prefrail population.

    Science.gov (United States)

    Millor, Nora; Lecumberri, Pablo; Gomez, Marisol; Martinez-Ramirez, Alicia; Rodriguez-Manas, Leocadio; Garcia-Garcia, Francisco José; Izquierdo, Mikel

    2013-07-01

    The aim of this study was to evaluate the inertial measures of the 30-s chair stand test using modern body-fixed motion sensors. Polynomial data fitting was used to correct the drift effect in the position estimation. Thereafter, the three most important test cycles phases ("impulse," "stand up," and "sit down") were characterized and automatically analyzed. Automated test control is provided, making it possible for researchers without engineering knowledge to run the test. A collection of meaningful data based on kinematic variables is selected for further research. The proposed methodology for data analysis is a feasible tool for use in clinical settings. This method may not only improve rehabilitation therapies but also identify people at risk for falls more accurately than simply evaluating the number of cycles.

  8. Development of new inertial technology and its application in aerospace field%新型惯性技术发展及在宇航领域的应用

    Institute of Scientific and Technical Information of China (English)

    王巍

    2016-01-01

    Dynamic precise measurement of movement information constructs the foundation of guidance, navigation and control of various vehicles. The inertial technology is the only independent means to establish the position and attitude reference of a vehicle in all kinds of environments, so it is the basis of dynamic precise measurement of movement information. The development of inertial technology, including optical gyroscope and its inertial navigation system, MEMS gyroscope and accelerometer, atom gyroscope and accelerometer, other kinds of gyroscope and accelerometer, micro-technology for positioning, navigation and timing, and inertial executer, was reviewed in this paper, and the main technology problems of these gyroscopes, accelerometers and inertial navigation systems which are needed to be resolved in aerospace field were proposed. The main application of these inertial technologies in domain aerospace field was described, including application in satellites, launch vehicles, manned aerospace and moon explore. Finally, three development trends of the inertial technology in aerospace field were given.%载体运动信息动态精确测量技术是现代各类运载体导航、制导与控制的前提,惯性技术是在各种复杂环境条件下自主地建立运动载体的方位、姿态基准的唯一有效手段,因而是载体运动信息精确测量的基础。文中详细介绍了光学惯性仪表及系统、MEMS惯性仪表、原子惯性仪表、其他惯性仪表、微型定位导航授时技术和惯性执行结构等新型惯性技术的发展历程,在宇航应用中需要解决的主要技术问题,阐述了惯性技术在宇航领域的应用情况和未来的发展需求和趋势。

  9. Inertial confinement fusion target component fabrication and technology development support: Annual report, October 1, 1997--September 30, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, J. [ed.

    1998-12-01

    During this period, General Atomics (GA) and their partner Schafer Corporation were assigned 17 formal tasks in support of the Inertial Confinement Fusion (ICF) program and its five laboratories. A portion of the effort on these tasks included providing direct ``On-site Support`` at Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), and Sandia National Laboratory Albuquerque (SNLA). They fabricated and delivered over 1,200 hohlraum mandrels and numerous other micromachined components to LLNL, LANL, and SNLA. They produced more than 1,300 glass and plastic target capsules for LLNL, LANL, SNLA, and the University of Rochester/Laboratory for Laser Energetics (UR/LLE). They also delivered nearly 2,000 various target foils and films for Naval Research Lab (NRL) and UR/LLE in FY98. This report describes these target fabrication activities and the target fabrication and characterization development activities that made the deliveries possible. During FY98, great progress was made by the GA/Schafer-UR/LLE-LANL team in the design, procurement, installation, and testing of the OMEGA Cryogenic Target System (OCTS) that will field cryogenic targets on OMEGA. The design phase was concluded for all components of the OCTS and all major components were procured and nearly all were fabricated. Many of the components were assembled and tested, and some have been shipped to UR/LLE. The ICF program is anticipating experiments at the OMEGA laser and the National Ignition Facility (NIF) which will require targets containing cryogenic layered D{sub 2} or deuterium-tritium (DT) fuel. They are part of the National Cryogenic Target Program and support experiments at LLNL and LANL to generate and characterize cryogenic layers for these targets. They also contributed cryogenic support and developed concepts for NIF cryogenic targets. This report summarizes and documents the technical progress made on these tasks.

  10. The technology of indirectly irradiated targets for inertial fusion researches at the Russian Federal nuclear center - VNIIEF

    Energy Technology Data Exchange (ETDEWEB)

    Andramanova, Y.V.; Veselov, A.V.; Zhidkov, N.V.; Ivanin, I.A.; Ignatev, Y.V.; Izgorodin, V.M.; Kirillov, G.A.; Komleva, G.A.; Makarov, M.Y.; Medvedev, E.F.; Morovov, A.P.; Nikolaev, G.P.; Pinegin, A.V.; Romaev, V.N.; Solomatina, E.Y.; Tacenko, M.V.; Tenyaev, B.N.; Cherkesova, I.N.; Yukhimchuk, A.A. [Russian Federal Nuclear Center, All-Russian Scientific Research Institute of Experimental Physics, RFNC-VNIIEF, Sarov (Russian Federation)

    2000-07-01

    The results of targets technology development for indirectly drive implosion experiments on the laser facility ISKRA-5, and also the constructions of targets developed at VNIIEF during last 4 years are represented. Moreover, a development of not destroying control methods for target parameters is written. (authors)

  11. Real-Time Digital Simulation of Inertial Response with Hardware-in-the-Loop Implementation on the CART3 Wind Turbine at the National Wind Technology Center

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wenzhong; Wang, Xiao; Muljadi, Eduard; Gevorgian, Vahan; Scholbrock, Andrew

    2017-09-01

    With increasing penetrations of wind power on electric grids, the stability and reliability of interconnected power systems may be impacted. In some countries that have developed renewable energy sources and systems, grid codes have been revised to require wind power plants (WPPs) to provide ancillary services to support the power system frequency in case of severe grid events. To do this, wind turbine generators (WTGs) should be deloaded to reserve a certain amount of active power for primary frequency response; however, deloading curtails annual energy production, and the market for this type of service needs to be further developed. In this report, we focus on the temporary frequency support provided by WTGs through inertial response. WTGs have potential to provide inertial response, but appropriate control methods should be implemented. With the implemented inertial control methods, wind turbines are capable of increasing their active power output by releasing some of their stored kinetic energy when a frequency excursion occurs. Active power can be temporarily boosted above the maximum power points, after which the rotor speed decelerates, and subsequently an active power output reduction restores the kinetic energy. In this report, we develop two types of models for wind power systems: the first is common, based on the wind power aerodynamic equation, and the power coefficient can be regressed using nonlinear functions; the second is much more complicated, wherein the wind turbine system is modeled using the Fatigue, Aerodynamics, Structures, and Turbulence Modeling (FAST) tool with several degrees of freedoms. A nine-bus test power system is built in Simulink and the Real-Time Digital Simulator, respectively, which are used to evaluate the frequency support performance of the WPPs. We implement two distinct types of inertial control methods in the modeled wind turbines: frequency-based inertial control (FBIC) and stepwise inertial control (SIC). We compare

  12. MEMS inertial sensors with integral rotation means.

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Stewart M.

    2003-09-01

    The state-of-the-art of inertial micro-sensors (gyroscopes and accelerometers) has advanced to the point where they are displacing the more traditional sensors in many size, power, and/or cost-sensitive applications. A factor limiting the range of application of inertial micro-sensors has been their relatively poor bias stability. The incorporation of an integral sensitive axis rotation capability would enable bias mitigation through proven techniques such as indexing, and foster the use of inertial micro-sensors in more accuracy-sensitive applications. Fabricating the integral rotation mechanism in MEMS technology would minimize the penalties associated with incorporation of this capability, and preserve the inherent advantages of inertial micro-sensors.

  13. A smartphone inertial balance

    Science.gov (United States)

    Barrera-Garrido, Azael

    2017-04-01

    In order to measure the mass of an object in the absence of gravity, one useful tool for many decades has been the inertial balance. One of the simplest forms of inertial balance is made by two mass holders or pans joined together with two stiff metal plates, which act as springs.

  14. 20 years of KVH fiber optic gyro technology: the evolution from large, low performance FOGs to compact, precise FOGs and FOG-based inertial systems

    Science.gov (United States)

    Napoli, Jay

    2016-05-01

    Precision fiber optic gyroscopes (FOGs) are critical components for an array of platforms and applications ranging from stabilization and pointing orientation of payloads and platforms to navigation and control for unmanned and autonomous systems. In addition, FOG-based inertial systems provide extremely accurate data for geo-referencing systems. Significant improvements in the performance of FOGs and FOG-based inertial systems at KVH are due, in large part, to advancements in the design and manufacture of optical fiber, as well as in manufacturing operations and signal processing. Open loop FOGs, such as those developed and manufactured by KVH Industries, offer tactical-grade performance in a robust, small package. The success of KVH FOGs and FOG-based inertial systems is due to innovations in key fields, including the development of proprietary D-shaped fiber with an elliptical core, and KVH's unique ThinFiber. KVH continually improves its FOG manufacturing processes and signal processing, which result in improved accuracies across its entire FOG product line. KVH acquired its FOG capabilities, including its patented E•Core fiber, when the company purchased Andrew Corporation's Fiber Optic Group in 1997. E•Core fiber is unique in that the light-guiding core - critical to the FOG's performance - is elliptically shaped. The elliptical core produces a fiber that has low loss and high polarization-maintaining ability. In 2010, KVH developed its ThinFiber, a 170-micron diameter fiber that retains the full performance characteristics of E•Core fiber. ThinFiber has enabled the development of very compact, high-performance open-loop FOGs, which are also used in a line of FOG-based inertial measurement units and inertial navigation systems.

  15. Study of High Precision Dynamic Initial Alignment Technology for Inertial Navigation System%惯导系统高精度动态对准技术研究

    Institute of Scientific and Technical Information of China (English)

    先治文; 胡小平; 练军想; 李冠南

    2013-01-01

    惯性导航初始对准技术是惯性导航的关键技术之一,而动态对准技术可以增强惯导系统的环境适应性.就GPS位置信息辅助下的惯性导航系统高精度动态对准技术进行研究.首先构建了15状态的Kalman滤波器,分析验证了Kalman滤波参数对于对准精度和对准速度的影响,在一定范围内,适当调整滤波参数,可以较好地改善滤波性能;然后在对准过程中使用了两位置转动观测增强的方法,提高了系统可观性,正确地估计比传感器件的零偏误差,并在纯惯导中加以补偿;最后通过跑车实验进行行车动态对准,达到了对准后24h纯惯导定位误差优于1 nmil的精度.%Inertial navigation is a process of integration, the main task of initial alignment of inertial navigation is determine the initial values of the integration and gyro drift errors and accelerometer biases. The initial alignment is one of the key technique of inertial navigation , in which dynamic initial alignment can improve the application of inertial navigation. In the paper, a high precision dynamic initial alignment technique is proposed for the GPS aided inertial navigation system (INS) on the moving base. This paper proposes the Kalman filter of 15 states, analyzes the effects of the Kalman parameters on the alignment accuracy and speed, showes that it will improve the performace of the filter that changing the Kalman paramaters properly. On the other hand, this paper uses the two-position a-lignment to improve the observability of the system, estimated the sensor-errores correctly then compensated them in the process of inertial navigation. Finally, the field-test used the high precision dynamic initial alignment technique, and the position error of navigation o-vermatch 1 nmile for 24 hours navigation.

  16. Solid state laser technology for inertial confinement fusion: A collection of articles from ''Energy and Technology Review''

    Energy Technology Data Exchange (ETDEWEB)

    1988-06-01

    This paper contains reprinted articles that record several milestones in laser research at LLNL. ''Neodymium-Glass Laser Research and Development at LLNL'' recounts the history of the Laser Program and our work on neodymium-glass lasers. ''Nova Laser Technology'' describes the capabilities of the Nova laser and some of its uses. ''Building Nova: Industry Relations and Technology Transfer'' illustrates the Laboratory's commitment to work with US industry in technology development. ''Managing the Nova Laser Project'' details the organization and close monitoring of costs and schedules during the construction of the Nova laser facility. The article ''Optical Coatings by the Sol-Gel Process,'' describes our chemical process for making the damage-resistant, antireflective silica coatings used on the Nova laser glass. The technical challenges in designing and fabricating the KDP crystal arrays used to convert the light wave frequency of the Nova lasers are reported in ''Frequency Conversion of the Nova Laser.'' Two articles, ''Eliminating Platinum Inclusions in Laser Glass'' and ''Detecting Microscopic Inclusions in Optical Glass,'' describe how we dealt with the problem of damaging metal inclusions in the Nova laser glass. The last article reprinted here, ''Auxilliary Target Chamber for Nova,'' discusses the diversion of two of Nova's ten beamlines into a secondary chamber for the purpose of increasing our capacity for experimentation.

  17. Indoor inertial waypoint navigation for the blind.

    Science.gov (United States)

    Riehle, Timothy H; Anderson, Shane M; Lichter, Patrick A; Whalen, William E; Giudice, Nicholas A

    2013-01-01

    Indoor navigation technology is needed to support seamless mobility for the visually impaired. This paper describes the construction and evaluation of an inertial dead reckoning navigation system that provides real-time auditory guidance along mapped routes. Inertial dead reckoning is a navigation technique coupling step counting together with heading estimation to compute changes in position at each step. The research described here outlines the development and evaluation of a novel navigation system that utilizes information from the mapped route to limit the problematic error accumulation inherent in traditional dead reckoning approaches. The prototype system consists of a wireless inertial sensor unit, placed at the users' hip, which streams readings to a smartphone processing a navigation algorithm. Pilot human trials were conducted assessing system efficacy by studying route-following performance with blind and sighted subjects using the navigation system with real-time guidance, versus offline verbal directions.

  18. Dual-use micromechanical inertial sensors

    Science.gov (United States)

    Elwell, John M., Jr.

    1995-03-01

    A new industry, which will provide low-cost silicon-based inertial sensors to the commercial and military markets. is being created. Inertial measurement units are used extensively in military systems, and new versions are expected to find their way into commercial products, such as automobiles, as production costs fall as technology advances. An automotive inertial measurement unit can be expected to perform a complete range of control, diagnostic, and navigation functions. These functions are expected to provide significant active safety, performance, comfort, convenience, and fuel economy advantages to the automotive consumer. An inertial measurement unit applicable to the automobile industry would meet many of the performance requirements for the military in important areas, such as antenna and image stabilization, autopilot control, and the guidance of smart weapons. Such a new industrial base will significantly reduce the acquisition cost of many future tactical weapons systems. An alliance, consisting of the Charles Stark Draper Laboratory and Rockwell International, has been created to develop inertial products for this new industry.

  19. Inertial Frames and Clock Rates

    CERN Document Server

    Kak, Subhash

    2012-01-01

    This article revisits the historiography of the problem of inertial frames. Specifically, the case of the twins in the clock paradox is considered to see that some resolutions implicitly assume inertiality for the non-accelerating twin. If inertial frames are explicitly identified by motion with respect to the large scale structure of the universe, it makes it possible to consider the relative inertiality of different frames.

  20. Stellar Populations

    NARCIS (Netherlands)

    Peletier, Reynier F.

    2013-01-01

    This is a summary of my lectures during the 2011 Canary Islands Winter School in Puerto de la Cruz. I give an introduction to the field of stellar populations in galaxies, and highlight some new results. Since the title of the Winter School is Secular Evolution in Galaxies I mostly concentrate on ne

  1. Stellar remnants

    CERN Document Server

    Kawaler, S D; Srinivasan, G

    1997-01-01

    This volume examines the internal structure, origin and evolution of white dwarfs, neutron stars and black holes, all objects at the final stage of stellar evolution. It covers topics such as: pulsation of white dwarfs; millisecond pulsars; and the dynamics around black holes.

  2. Microelectromechanical inertial sensor

    Energy Technology Data Exchange (ETDEWEB)

    Okandan, Murat (Edgewood, NM); Nielson, Gregory N. (Albuquerque, NM)

    2012-06-26

    A microelectromechanical (MEM) inertial sensor is disclosed which can be used to sense a linear acceleration, or a Coriolis acceleration due to an angular rotation rate, or both. The MEM inertial sensor has a proof mass which is supported on a bridge extending across an opening through a substrate, with the proof mass being balanced on the bridge by a pivot, or suspended from the bridge by the pivot. The proof mass can be oscillated in a tangential direction in the plane of the substrate, with any out-of-plane movement of the proof mass in response to a sensed acceleration being optically detected using transmission gratings located about an outer edge of the proof mass to generate a diffracted light pattern which changes with the out-of-plane movement of the proof mass.

  3. Inertial microfluidic pump

    Science.gov (United States)

    Kornilovitch, Pavel; Govyadinov, Alexander; Markel, David; Torniainen, Erik

    2015-11-01

    The inertial pump is powered by a microheater positioned near one end of a fluidic microchannel. As the microheater explosively boils the surrounding fluid, a vapor bubble expands and then collapses asymmetrically, resulting in net flow. Such devices become an effective means of transporting fluids at microscale. They have no moving parts and can be manufactured in large numbers using standard batch fabrication processes. In this presentation, physical principles behind pump operation are described, in particular the role of reservoirs in dissipating mechanical momentum and the expansion-collapse asymmetry. An effective one-dimensional dynamic model is formulated and solved. The model is compared with full three-dimensional CFD simulations and available experimental data. Potential applications of inertial micropumps are described.

  4. Micromachined Precision Inertial Instruments

    Science.gov (United States)

    2003-11-01

    and vacuum packaging techniques to achieve degree-per-hour inertial micro-gyroscopes. A single-wafer, all-silicon, high aspect-ratio p...Although vacuum packaging substantially reduces the mechanical noise of a surface micromachined accelerometer and lowers the output noise floor...it is desirable to operate sensors in atmosphere since vacuum packaging is not cost effective [15]. Figure 10: Performance improvements for In

  5. Inertial focusing of microparticles and its limitations

    Science.gov (United States)

    Cruz, FJ; Hooshmand Zadeh, S.; Wu, ZG; Hjort, K.

    2016-10-01

    Microfluidic devices are useful tools for healthcare, biological and chemical analysis and materials synthesis amongst fields that can benefit from the unique physics of these systems. In this paper we studied inertial focusing as a tool for hydrodynamic sorting of particles by size. Theory and experimental results are provided as a background for a discussion on how to extend the technology to submicron particles. Different geometries and dimensions of microchannels were designed and simulation data was compared to the experimental results.

  6. Stellar evolution

    CERN Document Server

    Meadows, A J

    2013-01-01

    Stellar Evolution, Second Edition covers the significant advances in the understanding of birth, life, and death of stars.This book is divided into nine chapters and begins with a description of the characteristics of stars according to their brightness, distance, size, mass, age, and chemical composition. The next chapters deal with the families, structure, and birth of stars. These topics are followed by discussions of the chemical composition and the evolution of main-sequence stars. A chapter focuses on the unique features of the sun as a star, including its evolution, magnetic fields, act

  7. Stellar Opacity

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, F J; Iglesias, C A

    1999-11-07

    The monochromatic opacity, {kappa}{sub v}, quantifies the property of a material to remove energy of frequency v from a radiation field. A harmonic average of {kappa}{sub v}, known as the Rosseland mean, {kappa}{sub R}, is frequently used to simplify the calculation of energy transport in stars. The term ''opacity'' is commonly understood to refer to {kappa}{sub R}. Opacity plays an important role in stellar modeling because for most stars radiation is the primary mechanism for transporting energy from the nuclear burning region in the core to the surface. Depending on the mass, convection and electron thermal conduction can also be important modes of stellar energy transport. The efficiency of energy transport is related to the temperature gradient, which is directly proportional to the mean radiative opacity in radiation dominated regions. When the radiative opacity is large, convection can become the more efficient energy transport mechanism. Electron conductive opacity, the resistance of matter to thermal conduction, is inversely proportional to electron thermal conductivity. Thermal conduction becomes the dominant mode of energy transport at high density and low temperature.

  8. Synchronization and Inertial Frames

    CERN Document Server

    Viazminsky, C P

    1999-01-01

    In classical mechanics, a procedure for simultaneous synchronization in all inertial frames is consistent with the Galilean transformation. However, if one attempts to achieve such a synchronization utilizing light signals, he will be facing in the first place the break down of simultaneity, and secondly, a self-contradictory transformation that has the Lorentz transformation, or its confinement to the velocity of light, as the only possible ways that resolve the contradiction. The current work constitutes a smooth transition from traditional to relativistic vision of mechanics, and therefore is quite appealing from pedagogical point of view.

  9. Stark broadening data for stellar plasma research.

    Science.gov (United States)

    Dimitrijević, M. S.

    Results of an effort to provide to astrophysicists and physicists an as much as possible complete set of Stark broadening parameters needed for stellar opacity calculations, stellar atmosphere modelling, abundance determinations and diagnostics of different plasmas in astrophysics, physics and plasma technology, are presented. Stark broadening has been considered within the semiclassical perturbation, and the modified semiempirical approaches.

  10. The Design of Cellphone Indoor Positioning System Based Magnetic Assisted Inertial Navigation Technology%基于惯导辅助地磁的手机室内定位系统设计

    Institute of Scientific and Technical Information of China (English)

    宋镖; 程磊; 周明达; 吴怀宇; 陈洋

    2015-01-01

    目前的室内定位技术大都是需要建立足够多的信号节点,这种有源信号受建筑物干扰衰减快导致其定位精度不足。为了避免这些存在的问题,通过深入研究室内定位方法,提出了基于惯导辅助地磁匹配的适用于手机移动终端的室内定位方法。有别于传统的室外定位系统,本文利用地球磁场在不同点的差异化信息,并通过选择适当的地磁匹配算法,可以实现不依赖于外部设备的移动个体室内定位,同时通过惯导辅助地磁的组合定位方式有效增加地磁信息匹配效率,能获得较高的室内定位的精度。最后设计了基于android平台的手机室内定位软件,可利用手机内置的传感器设备实现室内定位功能,仿真及实验显示该定位方法是有效的。%To implement indoor positioning,sufficient signal nodes fast attenuated by the interference of the con⁃struction and consequently cause the low positional accuracy,are mostly required. In order to avoid the existing problem,by further studying the technologies of indoor positioning,a positioning algorithm with inertial navigation technology assisted geomagnetic matching that suits for cellphone terminal indoor positioning is presented. Different from the traditional outdoor positioning system,by taking advantage of differentiated information of Earth's magnet⁃ic field at different points and selecting an appropriate geomagnetic matching algorithm ,the indoor positioning of cellphone devices without depending on external devices can be achieved,simultaneously applying the combined lo⁃calization method of inertial navigation-assisted geomagnetic positioning improve the indoor positioning accuracy. Finally,a cellphone indoor positioning software which is based on Android platform is novelly and successfully de⁃signed with mobile built-in sensors,Simulations and experiments show that this localization method is effective.

  11. Compact Stellarator Path to DEMO

    Science.gov (United States)

    Lyon, J. F.

    2007-11-01

    Issues for a DEMO reactor are sustaining an ignited/high-Q plasma in steady state, avoiding disruptions and large variations in power flux to the wall, adequate confinement of thermal plasma and alpha-particles, control of a burning plasma, particle and power handling, etc. Compact stellarators have key advantages -- steady-state high-plasma-density operation without external current drive or disruptions, stability without a close conducting wall or active feedback systems, and low recirculating power -- in addition to moderate plasma aspect ratio, good confinement, and high-beta potential. The ARIES-CS study established that compact stellarators can be competitive with tokamaks as reactors. Many of the issues for a compact stellarator DEMO can be answered using results from large tokamaks, ITER D-T experiments and fusion materials, technology and component development programs, in addition to stellarators in operation, under construction or in development. However, a large next-generation stellarator will be needed to address some physics issues: size scaling and confinement at higher parameters, burning plasma issues, and operation with a strongly radiative divertor. Technology issues include simpler coils, structure, and divertor fabrication, and better cost information.

  12. High throughput-per-footprint inertial focusing.

    Science.gov (United States)

    Ciftlik, Ata Tuna; Ettori, Maxime; Gijs, Martin A M

    2013-08-26

    Matching the scale of microfluidic flow systems with that of microelectronic chips for realizing monolithically integrated systems still needs to be accomplished. However, this is appealing only if such re-scaling does not compromise the fluidic throughput. This is related to the fact that the cost of microelectronic circuits primarily depends on the layout footprint, while the performance of many microfluidic systems, like flow cytometers, is measured by the throughput. The simple operation of inertial particle focusing makes it a promising technique for use in such integrated flow cytometer applications, however, microfluidic footprints demonstrated so far preclude monolithic integration. Here, the scaling limits of throughput-per-footprint (TPFP) in using inertial focusing are explored by studying the interplay between theory, the effect of channel Reynolds numbers up to 1500 on focusing, the entry length for the laminar flow to develop, and pressure resistance of the microchannels. Inertial particle focusing is demonstrated with a TPFP up to 0.3 L/(min cm²) in high aspect-ratio rectangular microfluidic channels that are readily fabricated with a post-CMOS integratable process, suggesting at least a 100-fold improvement compared to previously demonstrated techniques. Not only can this be an enabling technology for realizing cost-effective monolithically integrated flow cytometry devices, but the methodology represented here can also open perspectives for miniaturization of many biomedical microfluidic applications requiring monolithic integration with microelectronics without compromising the throughput.

  13. Accuracy Enhancement of Inertial Sensors Utilizing High Resolution Spectral Analysis

    Directory of Open Access Journals (Sweden)

    Michael Korenberg

    2012-08-01

    Full Text Available In both military and civilian applications, the inertial navigation system (INS and the global positioning system (GPS are two complementary technologies that can be integrated to provide reliable positioning and navigation information for land vehicles. The accuracy enhancement of INS sensors and the integration of INS with GPS are the subjects of widespread research. Wavelet de-noising of INS sensors has had limited success in removing the long-term (low-frequency inertial sensor errors. The primary objective of this research is to develop a novel inertial sensor accuracy enhancement technique that can remove both short-term and long-term error components from inertial sensor measurements prior to INS mechanization and INS/GPS integration. A high resolution spectral analysis technique called the fast orthogonal search (FOS algorithm is used to accurately model the low frequency range of the spectrum, which includes the vehicle motion dynamics and inertial sensor errors. FOS models the spectral components with the most energy first and uses an adaptive threshold to stop adding frequency terms when fitting a term does not reduce the mean squared error more than fitting white noise. The proposed method was developed, tested and validated through road test experiments involving both low-end tactical grade and low cost MEMS-based inertial systems. The results demonstrate that in most cases the position accuracy during GPS outages using FOS de-noised data is superior to the position accuracy using wavelet de-noising.

  14. Status and Prospects of the Fast Ignition Inertial Fusion Concept

    Energy Technology Data Exchange (ETDEWEB)

    Key, M H

    2006-11-15

    Fast ignition is an alternate concept in inertial confinement fusion, which has the potential for easier ignition and greater energy multiplication. If realized it could improve the prospects for inertial fusion energy. It poses stimulating challenges in science and technology and the research is approaching a key stage in which the feasibility of fast ignition will be determined. This review covers the concepts, the state of the science and technology, the near term prospects and the challenges and risks involved in demonstrating high gain fast ignition.

  15. The National Ignition Facility and the Promise of Inertial Fusion Energy

    Energy Technology Data Exchange (ETDEWEB)

    Moses, E I

    2010-12-13

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, CA, is now operational. The NIF is the world's most energetic laser system capable of producing 1.8 MJ and 500 TW of ultraviolet light. By concentrating the energy from its 192 extremely energetic laser beams into a mm{sup 3}-sized target, NIF can produce temperatures above 100 million K, densities of 1,000 g/cm{sup 3}, and pressures 100 billion times atmospheric pressure - conditions that have never been created in a laboratory and emulate those in planetary interiors and stellar environments. On September 29, 2010, the first integrated ignition experiment was conducted, demonstrating the successful coordination of the laser, cryogenic target system, array of diagnostics and infrastructure required for ignition demonstration. In light of this strong progress, the U.S. and international communities are examining the implication of NIF ignition for inertial fusion energy (IFE). A laser-based IFE power plant will require a repetition rate of 10-20 Hz and a laser with 10% electrical-optical efficiency, as well as further development and advances in large-scale target fabrication, target injection, and other supporting technologies. These capabilities could lead to a prototype IFE demonstration plant in the 10- to 15-year time frame. LLNL, in partnership with other institutions, is developing a Laser Inertial Fusion Engine (LIFE) concept and examining in detail various technology choices, as well as the advantages of both pure fusion and fusion-fission schemes. This paper will describe the unprecedented experimental capabilities of the NIF and the results achieved so far on the path toward ignition. The paper will conclude with a discussion about the need to build on the progress on NIF to develop an implementable and effective plan to achieve the promise of LIFE as a source of carbon-free energy.

  16. DRIE and Bonding Assisted Low Cost MEMS Processing of In-plane HAR Inertial Sensors

    NARCIS (Netherlands)

    Rajaraman, V.; Makinwa, K.A.A.; French, P.J.

    2008-01-01

    We present a simple, flexible and low cost MEMS fabrication process, developed using deep reactive ion etching (DRIE) and wafer bonding technologies, for manufacturing in-plane high aspect ratio (HAR) inertial sensors. Among examples, the design and fabrication results of a two axis inertial device

  17. DRIE and Bonding Assisted Low Cost MEMS Processing of In-plane HAR Inertial Sensors

    NARCIS (Netherlands)

    Rajaraman, V.; Makinwa, K.A.A.; French, P.J.

    2008-01-01

    We present a simple, flexible and low cost MEMS fabrication process, developed using deep reactive ion etching (DRIE) and wafer bonding technologies, for manufacturing in-plane high aspect ratio (HAR) inertial sensors. Among examples, the design and fabrication results of a two axis inertial device

  18. Fundamental stellar parameters

    CERN Document Server

    Wittkowski, M

    2004-01-01

    I present a discussion of fundamental stellar parameters and their observational determination in the context of interferometric measurements with current and future optical/infrared interferometric facilities. Stellar parameters and the importance of their determination for stellar physics are discussed. One of the primary uses of interferometry in the field of stellar physics is the measurement of the intensity profile across the stellar disk, both as a function of position angle and of wavelength. High-precision fundamental stellar parameters are also derived by characterizations of binary and multiple system using interferometric observations. This topic is discussed in detail elsewhere in these proceedings. Comparison of observed spectrally dispersed center-to-limb intensity variations with models of stellar atmospheres and stellar evolution may result in an improved understanding of key phenomena in stellar astrophysics such as the precise evolutionary effects on the main sequence, the evolution of meta...

  19. TEM turbulence optimisation in stellarators

    CERN Document Server

    Proll, J H E; Xanthopoulos, P; Lazerson, S A; Faber, B J

    2015-01-01

    With the advent of neoclassically optimised stellarators, optimising stellarators for turbulent transport is an important next step. The reduction of ion-temperature-gradient-driven turbulence has been achieved via shaping of the magnetic field, and the reduction of trapped-electron mode (TEM) turbulence is adressed in the present paper. Recent analytical and numerical findings suggest TEMs are stabilised when a large fraction of trapped particles experiences favourable bounce-averaged curvature. This is the case for example in Wendelstein 7-X [C.D. Beidler $\\textit{et al}$ Fusion Technology $\\bf{17}$, 148 (1990)] and other Helias-type stellarators. Using this knowledge, a proxy function was designed to estimate the TEM dynamics, allowing optimal configurations for TEM stability to be determined with the STELLOPT [D.A. Spong $\\textit{et al}$ Nucl. Fusion $\\bf{41}$, 711 (2001)] code without extensive turbulence simulations. A first proof-of-principle optimised equilibrium stemming from the TEM-dominated stella...

  20. Stellar Polarimetry

    CERN Document Server

    Clarke, David

    2009-01-01

    Written by an experienced teacher and author, this must-have source for work with polarimetric equipment and polarimetry in astronomy conveys the knowledge of the technology and techniques needed to measure and interpret polarizations. As such, this monograph offers a brief introduction and refresher, while also covering in detail statistics and data treatment as well as telescope optics. For astronomers, physicists and those working in the optical industry.

  1. Advanced stellarator power plants

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.L.

    1994-07-01

    The stellarator is a class of helical/toroidal magnetic fusion devices. Recent international progress in stellarator power plant conceptual design is reviewed and comparisons in the areas of physics, engineering, and economics are made with recent tokamak design studies.

  2. Advanced stellarator power plants

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.L.

    1994-07-01

    The stellarator is a class of helical/toroidal magnetic fusion devices. Recent international progress in stellarator power plant conceptual design is reviewed and comparisons in the areas of physics, engineering, and economics are made with recent tokamak design studies.

  3. Free inertial modes in differentially rotating convective envelopes of low-mass stars : numerical exploration

    CERN Document Server

    Guenel, M; Mathis, S; Rieutord, M

    2015-01-01

    Tidally-excited inertial waves in stellar convective regions are a key mechanism for tidal dissipation in stars and therefore the evolution of close-in binary or planetary systems. As a first step, we explore here the impact of latitudinal differential rotation on the properties of free inertial modes and identify the different families of modes. We show that they differ from the case of solid-body rotation. Using an analytical approach as well as numerical calculations, we conclude that critical layers (where the Doppler-shifted frequency vanishes) could play a very important role for tidal dissipation.

  4. Stellarator status, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, J.F. (Oak Ridge National Lab., TN (USA)); Grieger, G.; Rau, F. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany, F.R.)); Iiyoshi, A. (National Inst. for Fusion Science, Nagoya (Japan)); Navarro, A.P. (Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain)); Kovrizhnykh, L.M. (AN SSSR, Moscow (USSR). Inst. Obshchey Fiziki); Pavlichenko, O.S. (AN Ukrain

    1990-07-01

    The present status of stellarator experiments and recent progress in stellarator research (both experimental and theoretical) are reported by groups in the United States, the USSR, Japan, Australia, and the European Community (the Federal Republic of Germany and Spain). Experiments under construction and studies of large, next-generation stellarators are also described. 73 refs., 11 figs., 4 tabs.

  5. Wide-Bandwidth, Ultra-Accurate, Composite Inertial Reference Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Applied Technology Associates (ATA) proposes to develop a new inertial sensor by combining two sensing phenomena in a single device. ATA has patented an advanced...

  6. Error reduction by combining strapdown inertial measurement units in a baseball stitch

    Science.gov (United States)

    Tracy, Leah

    A poor musical performance is rarely due to an inferior instrument. When a device is under performing, the temptation is to find a better device or a new technology to achieve performance objectives; however, another solution may be improving how existing technology is used through a better understanding of device characteristics, i.e., learning to play the instrument better. This thesis explores improving position and attitude estimates of inertial navigation systems (INS) through an understanding of inertial sensor errors, manipulating inertial measurement units (IMUs) to reduce that error and multisensor fusion of multiple IMUs to reduce error in a GPS denied environment.

  7. Inertial measurement unit using rotatable MEMS sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Stewart M.; Allen, James J.

    2006-06-27

    A MEM inertial sensor (e.g. accelerometer, gyroscope) having integral rotational means for providing static and dynamic bias compensation is disclosed. A bias compensated MEM inertial sensor is described comprising a MEM inertial sense element disposed on a rotatable MEM stage. A MEM actuator for drives the rotation of the stage between at least two predetermined rotational positions. Measuring and comparing the output of the MEM inertial sensor in the at least two rotational positions allows, for both static and dynamic bias compensation in inertial calculations based on the sensor's output. An inertial measurement unit (IMU) comprising a plurality of independently rotatable MEM inertial sensors and methods for making bias compensated inertial measurements are disclosed.

  8. Inertial measurement unit using rotatable MEMS sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Stewart M. (Albuquerque, NM); Allen, James J. (Albuquerque, NM)

    2007-05-01

    A MEM inertial sensor (e.g. accelerometer, gyroscope) having integral rotational means for providing static and dynamic bias compensation is disclosed. A bias compensated MEM inertial sensor is described comprising a MEM inertial sense element disposed on a rotatable MEM stage. A MEM actuator drives the rotation of the stage between at least two predetermined rotational positions. Measuring and comparing the output of the MEM inertial sensor in the at least two rotational positions allows for both static and dynamic bias compensation in inertial calculations based on the sensor's output. An inertial measurement unit (IMU) comprising a plurality of independently rotatable MEM inertial sensors and methods for making bias compensated inertial measurements are disclosed.

  9. Inertial measurement unit using rotatable MEMS sensors

    Science.gov (United States)

    Kohler, Stewart M.; Allen, James J.

    2007-05-01

    A MEM inertial sensor (e.g. accelerometer, gyroscope) having integral rotational means for providing static and dynamic bias compensation is disclosed. A bias compensated MEM inertial sensor is described comprising a MEM inertial sense element disposed on a rotatable MEM stage. A MEM actuator drives the rotation of the stage between at least two predetermined rotational positions. Measuring and comparing the output of the MEM inertial sensor in the at least two rotational positions allows for both static and dynamic bias compensation in inertial calculations based on the sensor's output. An inertial measurement unit (IMU) comprising a plurality of independently rotatable MEM inertial sensors and methods for making bias compensated inertial measurements are disclosed.

  10. Study on Improvement of Accuracy in Inertial Photogrammetry by Combining Images with Inertial Measurement Unit

    Science.gov (United States)

    Kawasaki, Hideaki; Anzai, Shojiro; Koizumi, Toshio

    2016-06-01

    Inertial photogrammetry is defined as photogrammetry that involves using a camera on which an inertial measurement unit (IMU) is mounted. In inertial photogrammetry, the position and inclination of a shooting camera are calculated using the IMU. An IMU is characterized by error growth caused by time accumulation because acceleration is integrated with respect to time. This study examines the procedure to estimate the position of the camera accurately while shooting using the IMU and the structure from motion (SfM) technology, which is applied in many fields, such as computer vision. When neither the coordinates of the position of the camera nor those of feature points are known, SfM provides a similar positional relationship between the position of the camera and feature points. Therefore, the actual length of positional coordinates is not determined. If the actual length of the position of the camera is unknown, the camera acceleration is obtained by calculating the second order differential of the position of the camera, with respect to the shooting time. The authors had determined the actual length by assigning the position of IMU to the SfM-calculated position. Hence, accuracy decreased because of the error growth, which was the characteristic feature of IMU. In order to solve this problem, a new calculation method was proposed. Using this method, the difference between the IMU-calculated acceleration and the camera-calculated acceleration can be obtained using the method of least squares, and the magnification required for calculating the actual dimension from the position of the camera can be obtained. The actual length can be calculated by multiplying all the SfM point groups by the obtained magnification factor. This calculation method suppresses the error growth, which is due to the time accumulation in IMU, and improves the accuracy of inertial photogrammetry.

  11. Inertial Response of Wind Power Plants: A Comparison of Frequency-Based Inertial Control and Stepwise Inertial Control

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao; Gao, Wenzhong; Wang, Jianhui; Yan, Shijie; Wu, Ziping; Yan, Weihang; Gevorgian, Vahan; Muljadi, Eduard; Kang, Moses; Hwang, Min; Kang, YongCheol

    2016-11-21

    The frequency regulation capability of a wind power plant plays an important role in enhancing frequency reliability especially in an isolated power system with high wind power penetration levels. A comparison of two types of inertial control methods, namely frequency-based inertial control (FBIC) and stepwise inertial control (SIC), is presented in this paper. Comprehensive case studies are carried out to reveal features of the different inertial control methods, simulated in a modified Western System Coordination Council (WSCC) nine-bus power grid using real-time digital simulator (RTDS) platform. The simulation results provide an insight into the inertial control methods under various scenarios.

  12. Real-time precision pedestrian navigation solution using Inertial Navigation System and Global Positioning System

    Directory of Open Access Journals (Sweden)

    Yong-Jin Yoon

    2015-03-01

    Full Text Available Global Positioning System and Inertial Navigation System can be used to determine position and velocity. A Global Positioning System module is able to accurately determine position without sensor drift, but its usage is limited in heavily urbanized environments and heavy vegetation. While high-cost tactical-grade Inertial Navigation System can determine position accurately, low-cost micro-electro-mechanical system Inertial Navigation System sensors are plagued by significant errors. Global Positioning System is coupled with Inertial Navigation System to correct the errors, while Inertial Navigation System itself can be used to provide navigation solution during a Global Positioning System outage. Data from Global Positioning System and Inertial Navigation System can be integrated by extensive Kalman filtering, using loosely coupled integration architecture to provide navigation solutions. In this study, real-time low-cost loosely coupled micro-electro-mechanical system Inertial Navigation System/Global Positioning System sensors have been used for pedestrian navigation. Trial runs of Global Positioning System outages have been conducted to determine the accuracy of the system described. The micro-electro-mechanical system Inertial Navigation System/Global Positioning System can successfully project a trajectory during a Global Positioning System outage and produces a root mean square error of 9.35 m in latitude direction and 10.8 m in longitude direction. This technology is very suitable for visually impaired pedestrians.

  13. Design of the Wendelstein 7-X inertially cooled Test Divertor Unit Scraper Element

    Energy Technology Data Exchange (ETDEWEB)

    Lumsdaine, Arnold, E-mail: lumsdainea@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Boscary, Jean [Max Planck Institute for Plasma Physics, Garching (Germany); Fellinger, Joris [Max Planck Institute for Plasma Physics, Greifswald (Germany); Harris, Jeff [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Hölbe, Hauke; König, Ralf [Max Planck Institute for Plasma Physics, Greifswald (Germany); Lore, Jeremy; McGinnis, Dean [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Neilson, Hutch; Titus, Peter [Princeton Plasma Physics Lab, Princeton, NJ (United States); Tretter, Jörg [Max Planck Institute for Plasma Physics, Garching (Germany)

    2015-10-15

    Highlights: • The justification for the installation of the Test Divertor Unit Scraper Element is given. • Specially designed operational scenarios for the component are presented. • Plans for the design of the component are detailed. - Abstract: The Wendelstein 7-X stellarator is scheduled to begin operation in 2015, and to achieve full power steady-state operation in 2019. Computational simulations have indicated that for certain plasma configurations in the steady-state operation, the ends of the divertor targets may receive heat fluxes beyond their qualified technological limit. To address this issue, a high heat-flux “scraper element” (HHF-SE) has been designed that can protect the sensitive divertor target region. The surface profile of the HHF-SE has been carefully designed to meet challenging engineering requirements and severe spatial limitations through an iterative process involving physics simulations, engineering analysis, and computer aided design rendering. The desire to examine how the scraper element interacts with the plasma, both in terms of how it protects the divertor, and how it affects the neutral pumping efficiency, has led to the consideration of installing an inertially cooled version during the short pulse operation phase. This Test Divertor Unit Scraper Element (TDU-SE) would replicate the surface profile of the HHF-SE. The design and instrumentation of this component must be completed carefully in order to satisfy the requirements of the machine operation, as well as to support the possible installation of the HHF-SE for steady-state operation.

  14. In-flight Quality and Accuracy of Attitude Measurements from the CHAMP Advanced Stellar Compass

    DEFF Research Database (Denmark)

    Jørgensen, Peter Siegbjørn; Jørgensen, John Leif; Denver, Troelz;

    2005-01-01

    The German geo-observations satellite CHAMP carries highly accurate vector instruments. The orientation of these relative to the inertial reference frame is obtained using star trackers. These advanced stellar compasses (ASC) are fully autonomous units, which provide, in real time, the absolute...

  15. Rest mass or inertial mass?

    OpenAIRE

    Khrapko, R. I.

    2001-01-01

    Rest mass takes the place of inertial mass in modern physics textbooks. It seems to be wrong. But this phenomenon is hidden away by the facts that rest mass adherents busily call rest mass "mass", not rest mass, and the word "mass" is associated with a measure of inertia. This topic has been considered by the author in the article "What is mass?" [1, 2, 3]. Additional arguments to a confirmation of such a thesis are presented here.

  16. OF INERTIAL PROPERTIES OF SOILS

    Directory of Open Access Journals (Sweden)

    Sargsjan Akop Egishovich

    2012-10-01

    The article describes the motion of the construction foundation slab as a rigid body with six degrees of freedom on the surface of the inertial linearly deformable semi-space. The dynamic mechanical model of the base is presented as six pairs of parallel-connected springs and dampers that characterize the rigidity of the base subjected to ultimate forces (three forces alongside the axes and three moments in relation to the axes.

  17. Inertial measurement using atom interferometry

    Institute of Scientific and Technical Information of China (English)

    JIA; Aiai; YANG; Jun; YAN; Shuhua; LUO; Yukun; HU; Qingqing; WEI; Chunhua; LI; Zehuan

    2015-01-01

    The recent advances of atom interferometer and its application in precision inertial measurement are review ed. The principle,characteristics and implementation of atom interferometer are introduced and it can be used to measure gravitational acceleration,gravity gradient and rotation for its high sensitivity. We also present the principle,structure and new progress of gravimeter,gravity gradiometer and gyroscope based on atom interferometer.

  18. Inertial imaging with nanomechanical systems

    Science.gov (United States)

    Hanay, M. Selim; Kelber, Scott I.; O’Connell, Cathal D.; Mulvaney, Paul; Sader, John E.; Roukes, Michael L.

    2017-01-01

    Mass sensing with nanoelectromechanical systems has advanced significantly during the last decade. With nanoelectromechanical systems sensors it is now possible to carry out ultrasensitive detection of gaseous analytes, to achieve atomic-scale mass resolution and to perform mass spectrometry on single proteins. Here, we demonstrate that the spatial distribution of mass within an individual analyte can be imaged—in real time and at the molecular scale—when it adsorbs onto a nanomechanical resonator. Each single-molecule adsorption event induces discrete, time-correlated perturbations to all modal frequencies of the device. We show that by continuously monitoring a multiplicity of vibrational modes, the spatial moments of mass distribution can be deduced for individual analytes, one-by-one, as they adsorb. We validate this method for inertial imaging, using both experimental measurements of multimode frequency shifts and numerical simulations, to analyse the inertial mass, position of adsorption and the size and shape of individual analytes. Unlike conventional imaging, the minimum analyte size detectable through nanomechanical inertial imaging is not limited by wavelength-dependent diffraction phenomena. Instead, frequency fluctuation processes determine the ultimate attainable resolution. Advanced nanoelectromechanical devices appear capable of resolving molecular-scale analytes. PMID:25822931

  19. Stellar Presentations (Abstract)

    Science.gov (United States)

    Young, D.

    2015-12-01

    (Abstract only) The AAVSO is in the process of expanding its education, outreach and speakers bureau program. powerpoint presentations prepared for specific target audiences such as AAVSO members, educators, students, the general public, and Science Olympiad teams, coaches, event supervisors, and state directors will be available online for members to use. The presentations range from specific and general content relating to stellar evolution and variable stars to specific activities for a workshop environment. A presentation—even with a general topic—that works for high school students will not work for educators, Science Olympiad teams, or the general public. Each audience is unique and requires a different approach. The current environment necessitates presentations that are captivating for a younger generation that is embedded in a highly visual and sound-bite world of social media, twitter and U-Tube, and mobile devices. For educators, presentations and workshops for themselves and their students must support the Next Generation Science Standards (NGSS), the Common Core Content Standards, and the Science Technology, Engineering and Mathematics (STEM) initiative. Current best practices for developing relevant and engaging powerpoint presentations to deliver information to a variety of targeted audiences will be presented along with several examples.

  20. Stellar feedback efficiencies: supernovae versus stellar winds

    CERN Document Server

    Fierlinger, Katharina M; Ntormousi, Evangelia; Fierlinger, Peter; Schartmann, Marc; Ballone, Alessandro; Krause, Martin G H; Diehl, Roland

    2015-01-01

    Stellar winds and supernova (SN) explosions of massive stars ("stellar feedback") create bubbles in the interstellar medium (ISM) and insert newly produced heavy elements and kinetic energy into their surroundings, possibly driving turbulence. Most of this energy is thermalized and immediately removed from the ISM by radiative cooling. The rest is available for driving ISM dynamics. In this work we estimate the amount of feedback energy retained as kinetic energy when the bubble walls have decelerated to the sound speed of the ambient medium. We show that the feedback of the most massive star outweighs the feedback from less massive stars. For a giant molecular cloud (GMC) mass of 1e5 solar masses (as e.g. found in the Orion GMCs) and a star formation efficiency of 8% the initial mass function predicts a most massive star of approximately 60 solar masses. For this stellar evolution model we test the dependence of the retained kinetic energy of the cold GMC gas on the inclusion of stellar winds. In our model w...

  1. Stellar Echo Imaging of Exoplanets

    Science.gov (United States)

    Mann, Chris; Lerch, Kieran; Lucente, Mark; Meza-Galvan, Jesus; Mitchell, Dan; Ruedin, Josh; Williams, Spencer; Zollars, Byron

    2016-01-01

    All stars exhibit intensity fluctuations over several timescales, from nanoseconds to years. These intensity fluctuations echo off bodies and structures in the star system. We posit that it is possible to take advantage of these echoes to detect, and possibly image, Earth-scale exoplanets. Unlike direct imaging techniques, temporal measurements do not require fringe tracking, maintaining an optically-perfect baseline, or utilizing ultra-contrast coronagraphs. Unlike transit or radial velocity techniques, stellar echo detection is not constrained to any specific orbital inclination. Current results suggest that existing and emerging technology can already enable stellar echo techniques at flare stars, such as Proxima Centauri, including detection, spectroscopic interrogation, and possibly even continent-level imaging of exoplanets in a variety of orbits. Detection of Earth-like planets around Sun-like stars appears to be extremely challenging, but cannot be fully quantified without additional data on micro- and millisecond-scale intensity fluctuations of the Sun. We consider survey missions in the mold of Kepler and place preliminary constraints on the feasibility of producing 3D tomographic maps of other structures in star systems, such as accretion disks. In this report we discuss the theory, limitations, models, and future opportunities for stellar echo imaging.

  2. An integrated platform for inertial navigation systems

    Science.gov (United States)

    Dumitrascu, Ana; Tamas, Razvan D.; Caruntu, George; Bobirca, Daniel

    2015-02-01

    In this paper we propose a new configuration for an inertial navigation system (INS), type strap down, designed to be used onboard a ship. The system consists of an inertial navigation unit (IMU), using a 9-axis inertial sensor and pressure and temperature sensors, a GPS module, various interfaces for optimal communication and command, a microcontroller for data processing and computing and a power supply.

  3. Microminiature Inertial Measurement System and Its Applications

    Institute of Scientific and Technical Information of China (English)

    毛刚; 顾启泰

    2001-01-01

    The microminiature inertial measurement system, a new style of inertial measurement system, hasmany advantages compared with traditional systems, such as small size, Iow mass, low cost, low powerconsumption, high bearing capacity, and long life. Undoubtedly, it will have wide applications in military andcommercial fields. However, current micro inertial sensors do not have sufficient accuracy, so, its applicationsare limited to some extent. This paper describes a microminiature inertial measurement system and its design,operating theory and error control techniques. In addition, its performance and applications are evaluated.``

  4. Generation of Accelerated Stability Experiment Profile of Inertial Platform Based on Finite Element

    Institute of Scientific and Technical Information of China (English)

    CHEN Yunxia; HUANG Xiaokai; KANG Rui

    2012-01-01

    The residual stress generated in the manufacturing process of inertial platform causes the drift of inertial platform parameters in long-term storage condition.However,the existing temperature cycling experiment could not meet the increased repeatability technical requirements of inertial platform parameters.In order to solve this problem,in this paper,firstly the Unigraphics (UG) software and the interface compatibility of ANSYS software are used to establish the inertial platform finite element model.Secondly,the residual stress is loaded into finite element model by ANSYS function editor in the form of surface loads to analyze the efficiency.And then,the generation based on ANSYS simulation inertial platform to accelerate the stability of experiment profile is achieved by the application of the analysis method of orthogonal experimental design and ANSYS thermal-structural coupling.The optimum accelerated stability experiment profile is determined finally,which realizes the rapid,effective release of inertial platform residual stress.The research methodology and conclusion of this paper have great theoretical and practical significance to the production technology of inertial platform.

  5. The National Ignition Facility: The Path to Ignition, High Energy Density Science and Inertial Fusion Energy

    Energy Technology Data Exchange (ETDEWEB)

    Moses, E

    2011-03-25

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, CA, is a Nd:Glass laser facility capable of producing 1.8 MJ and 500 TW of ultraviolet light. This world's most energetic laser system is now operational with the goals of achieving thermonuclear burn in the laboratory and exploring the behavior of matter at extreme temperatures and energy densities. By concentrating the energy from its 192 extremely energetic laser beams into a mm{sup 3}-sized target, NIF can produce temperatures above 100 million K, densities of 1,000 g/cm{sup 3}, and pressures 100 billion times atmospheric pressure - conditions that have never been created in a laboratory and emulate those in the interiors of planetary and stellar environments. On September 29, 2010, NIF performed the first integrated ignition experiment which demonstrated the successful coordination of the laser, the cryogenic target system, the array of diagnostics and the infrastructure required for ignition. Many more experiments have been completed since. In light of this strong progress, the U.S. and the international communities are examining the implication of achieving ignition on NIF for inertial fusion energy (IFE). A laser-based IFE power plant will require a repetition rate of 10-20 Hz and a 10% electrical-optical efficiency laser, as well as further advances in large-scale target fabrication, target injection and tracking, and other supporting technologies. These capabilities could lead to a prototype IFE demonstration plant in 10- to 15-years. LLNL, in partnership with other institutions, is developing a Laser Inertial Fusion Energy (LIFE) baseline design and examining various technology choices for LIFE power plant This paper will describe the unprecedented experimental capabilities of the NIF, the results achieved so far on the path toward ignition, the start of fundamental science experiments and plans to transition NIF to an international user facility

  6. Double-helix stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Moroz, P.E.

    1997-09-01

    A new stellarator configuration, the Double-Helix Stellarator (DHS), is introduced. This novel configuration features a double-helix center post as the only helical element of the stellarator coil system. The DHS configuration has many unique characteristics. One of them is the extreme low plasma aspect ratio, A {approx} 1--1.2. Other advantages include a high enclosed volume, appreciable rotational transform, and a possibility of extreme-high-{beta} MHD equilibria. Moreover, the DHS features improved transport characteristics caused by the absence of the magnetic field ripple on the outboard of the torus. Compactness, simplicity and modularity of the coil system add to the DHS advantages for fusion applications.

  7. Observability of Inertial Navigation System

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To improve the observability of strapdown inertial navigation system and the effectiveness of Kalman filter in the navigation system, the method of estimating the observability is analyzed based on eigenvalues and eigenvectors which are proved to be availabe, on this basis two-position alignment technigue is applied. The simulation shows that two-position alignment really makes the system's observability change from being incomplete to being complete, and the test method based on eigenvalues and eigenvectors is available to determine the observability of every state vector.

  8. Trends of Stellar Entropy along Stellar Evolution

    CERN Document Server

    de Avellar, Marcio G B; Horvath, Jorge E

    2015-01-01

    This paper is devoted to discuss the difference in the thermodynamic entropy budget {\\it per baryon} in each type of stellar object found in Universe. We track and discuss the actual {\\it decrease} of the stored baryonic thermodynamic entropy from the most primitive molecular cloud up to the final fate of matter in the black holes, passing through evolved states of matter as found in white dwarfs and neutron stars. We then discuss the case of actual stars of different masses throughout their {\\it evolution}, clarifying the role of virial equilibrium condition for the decrease of the entropy and related issues. Finally, we discuss how gravity ultimately drives composition, hence structural changes along the stellar evolution all the way until the ultimate collapse to black holes, which may increase dramatically their entropy because of the gravitational contribution itself.

  9. Stellar ages from asteroseismology

    CERN Document Server

    Lebreton, Yveline

    2008-01-01

    Asteroseismology provides powerful means to probe stellar interiors. The oscillations frequencies are closely related to stellar interior properties via the density and sound speed profiles. Since these are tightly linked with the mass and evolutionary state, we can expect to determine the age and mass of a star from the comparison of its oscillation spectrum with predictions of stellar models. Such a comparison suffers both from the problems we face when modeling a particular star (as the uncertainties on global parameters and chemical composition) and from our misunderstanding of processes at work in stellar interiors (as the transport processes that may lead to core mixing and affect the model ages). For stars where observations have provided precise and numerous oscillation frequencies together with accurate global parameters and additional information (as the radius or the mass if the star is in a binary system, the interferometric radius or the mean density if the star is an exoplanet host), we can also...

  10. Stellar Chromospheric Activity

    Directory of Open Access Journals (Sweden)

    Hall Jeffrey C.

    2008-03-01

    Full Text Available The Sun, stars similar to it, and many rather dissimilar to it, have chromospheres, regions classically viewed as lying above the brilliant photosphere and characterized by a positive temperature gradient and a marked departure from radiative equilibrium. Stellar chromospheres exhibit a wide range of phenomena collectively called activity, stemming largely from the time evolution of their magnetic fields and the mass flux and transfer of radiation through the complex magnetic topology and the increasingly optically thin plasma of the outer stellar atmosphere. In this review, I will (1 outline the development of our understanding of chromospheric structure from 1960 to the present, (2 discuss the major observational programs and theoretical lines of inquiry, (3 review the origin and nature of both solar and stellar chromospheric activity and its relationship to, and effect on, stellar parameters including total energy output, and (4 summarize the outstanding problems today.

  11. Advanced Stellar Compass

    DEFF Research Database (Denmark)

    Madsen, Peter Buch; Jørgensen, John Leif; Thuesen, Gøsta;

    1997-01-01

    This document describes all interface properties for the Advanced Stellar Compass, developed for the German Research Satellite "CHAMP". Basic operations, modes, software protocol, calibration methods and closed loop test strategies are described.......This document describes all interface properties for the Advanced Stellar Compass, developed for the German Research Satellite "CHAMP". Basic operations, modes, software protocol, calibration methods and closed loop test strategies are described....

  12. Inertial sensors for smartphones navigation.

    Science.gov (United States)

    Dabove, P; Ghinamo, G; Lingua, A M

    2015-01-01

    The advent of smartphones and tablets, means that we can constantly get information on our current geographical location. These devices include not only GPS/GNSS chipsets but also mass-market inertial platforms that can be used to plan activities, share locations on social networks, and also to perform positioning in indoor and outdoor scenarios. This paper shows the performance of smartphones and their inertial sensors in terms of gaining information about the user's current geographical locatio n considering an indoor navigation scenario. Tests were carried out to determine the accuracy and precision obtainable with internal and external sensors. In terms of the attitude and drift estimation with an updating interval equal to 1 s, 2D accuracies of about 15 cm were obtained with the images. Residual benefits were also obtained, however, for large intervals, e.g. 2 and 5 s, where the accuracies decreased to 50 cm and 2.2 m, respectively.

  13. Mechanical Energy Change in Inertial Reference Frames

    Science.gov (United States)

    Ghanbari, Saeed

    2016-01-01

    The mechanical energy change of a system in an inertial frame of reference equals work done by the total nonconservative force in the same frame. This relation is covariant under the Galilean transformations from inertial frame S to S', where S' moves with constant velocity relative to S. In the presence of nonconservative forces, such as normal…

  14. Inertial modes of slowly rotating isentropic stars

    CERN Document Server

    Yoshida, S; Yoshida, Shijun; Lee, Umin

    2000-01-01

    We investigate inertial mode oscillations of slowly and uniformly rotating, isentropic, Newtonian stars. Inertial mode oscillations are induced by the Coriolis force due to the star's rotation, and their characteristic frequencies are comparable with the rotation frequency $\\Omega$ of the star. So called r-mode oscillations form a sub-class of the inertial modes. In this paper, we use the term ``r-modes'' to denote the inertial modes for which the toroidal motion dominates the spheroidal motion, and the term ``inertial modes'' to denote the inertial modes for which the toroidal and spheroidal motions have comparable amplitude to each other. Using the slow rotation approximation consistent up to the order of $\\Omega^3$, we study the properties of the inertial modes and r-modes, by taking account of the effect of the rotational deformation of the equilibrium on the eigenfrequencies and eigenfunctions. The eigenfrequencies of the r-modes and inertial modes calculated in this paper are in excellent agreement with...

  15. Application of inertial instruments for DSN antenna pointing and tracking

    Science.gov (United States)

    Eldred, D. B.; Nerheim, N. M.; Holmes, K. G.

    1990-05-01

    The feasibility of using inertial instruments to determine the pointing attitude of the NASA Deep Space Network antennas is examined. The objective is to obtain 1 mdeg pointing knowledge in both blind pointing and tracking modes to facilitate operation of the Deep Space Network 70 m antennas at 32 GHz. A measurement system employing accelerometers, an inclinometer, and optical gyroscopes is proposed. The initial pointing attitude is established by determining the direction of the local gravity vector using the accelerometers and the inclinometer, and the Earth's spin axis using the gyroscopes. Pointing during long-term tracking is maintained by integrating the gyroscope rates and augmenting these measurements with knowledge of the local gravity vector. A minimum-variance estimator is used to combine measurements to obtain the antenna pointing attitude. A key feature of the algorithm is its ability to recalibrate accelerometer parameters during operation. A survey of available inertial instrument technologies is also given.

  16. Lagrangian coherent structures and inertial particle dynamics

    CERN Document Server

    Sudharsan, M; Riley, James J

    2015-01-01

    In this work we investigate the dynamics of inertial particles using finite-time Lyapunov exponents (FTLE). In particular, we characterize the attractor and repeller structures underlying preferential concentration of inertial particles in terms of FTLE fields of the underlying carrier fluid. Inertial particles that are heavier than the ambient fluid (aerosols) attract onto ridges of the negative-time fluid FTLE. This negative-time FTLE ridge becomes a repeller for particles that are lighter than the carrier fluid (bubbles). We also examine the inertial FTLE (iFTLE) determined by the trajectories of inertial particles evolved using the Maxey-Riley equations with non-zero Stokes number and density ratio. Finally, we explore the low-pass filtering effect of Stokes number. These ideas are demonstrated on two-dimensional numerical simulations of the unsteady double gyre flow.

  17. Fluvial experiments using inertial sensors.

    Science.gov (United States)

    Maniatis, Georgios; Valyrakis, Manousos; Hodge, Rebecca; Drysdale, Tim; Hoey, Trevor

    2017-04-01

    During the last four years we have announced results on the development of a smart pebble that is constructed and calibrated specifically for capturing the dynamics of coarse sediment motion in river beds, at a grain scale. In this presentation we report details of our experimental validation across a range of flow regimes. The smart pebble contains Inertial Measurements Units (IMUs), which are sensors capable of recording the inertial acceleration and the angular velocity of the rigid bodies into which they are attached. IMUs are available across a range of performance levels, with commensurate increase in size, cost and performance as one progresses from integrated-circuit devices for use in commercial applications such as gaming and mobile phones, to larger brick-sized systems sometimes found in industrial applications such as vibration monitoring and quality control, or even the rack-mount equipment used in some aerospace and navigation applications (which can go as far as to include lasers and optical components). In parallel with developments in commercial and industrial settings, geomorphologists started recently to explore means of deploying IMUs in smart pebbles. The less-expensive, chip-scale IMUs have been shown to have adequate performance for this application, as well as offering a sufficiently compact form-factor. Four prototype sensors have been developed so far, and the latest (400 g acceleration range, 50-200 Hz sampling frequency) has been tested in fluvial laboratory experiments. We present results from three different experimental regimes designed for the evaluation of this sensor: a) an entrainment threshold experiment ; b) a bed impact experiment ; and c) a rolling experiment. All experiments used a 100 mm spherical sensor, and set a) were repeated using an equivalent size elliptical sensor. The experiments were conducted in the fluvial laboratory of the University of Glasgow (0.9 m wide flume) under different hydraulic conditions. The use of

  18. Stellar compass for the Clementine Mission

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, B. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    A CCD sensor with 42 x 28 degrees FOV and 576 x 384 pixels was built by the Advanced Technology Program (ATP) in the Physics Department at LLNL. That sensor, called the StarTracker camera, is used on the Clementine Lunar Mapping mission between January and May, 1994. Together with the Stellar Compass software, the StarTracker camera provided a way of identifying its orientation to within about 150 microradians in camera body pitch and yaw. This presentation will be an overview of basically how the Stellar Compass software works, along with showing some of its performance results.

  19. Inertial mass from Unruh temperatures

    Science.gov (United States)

    Giné, J.; McCulloch, M. E.

    2016-05-01

    It has been proposed that inertia can be explained as follows: when objects accelerate in one direction, a Rindler horizon forms in the other direction suppressing Unruh radiation on that side and producing a net Unruh radiation pressure that always opposes the acceleration, just like inertia. So far, this model has predicted masses over twice those expected. In this paper, an error in this model is corrected so that its prediction improves to within 29% of the expected Planck mass. It is also shown that inertial mass may be understood qualitatively by applying Carnot’s principle and entropy to Unruh temperatures, so that the work needed for inertia comes from the difference in the Unruh temperatures seen by the accelerated object and the cosmos. This implies that highly-accelerated systems may emit heat in a new way.

  20. PREFACE: A Stellar Journey A Stellar Journey

    Science.gov (United States)

    Asplund, M.

    2008-10-01

    The conference A Stellar Journey was held in Uppsala, Sweden, 23 27June 2008, in honour of Professor Bengt Gustafsson's 65th birthday. The choice of Uppsala as the location for this event was obvious given Bengt's long-standing association with the city stemming back to his school days. With the exception of a two-year postdoc stint in Copenhagen, five years as professor at Stockholm University and two years as director of the Sigtuna foundation, Bengt has forged his illustrious professional career at Uppsala University. The symposium venue was Museum Gustavianum, once the main building of the oldest university in Scandinavia. The title of the symposium is a paraphrasing of Bengt's popular astronomy book Kosmisk Resa (in English: Cosmic Journey) written in the early eighties. I think this aptly symbolizes his career that has been an astronomical voyage from near to far, from the distant past to the present. The original book title was modified slightly to reflect that most of his work to date has dealt with stars in one way or another. In addition it also gives credit to Bengt's important role as a guiding light for a very large number of students, colleagues and collaborators, indeed for several generations of astronomers. For me personally, the book Kosmisk Resa bears particular significance as it has shaped my life rather profoundly. Although I had already decided to become an astronomer, when I first read the book as a 14-year-old I made up my mind then and there that I would study under Bengt Gustafsson and work on stars. Indeed I have remained true to this somewhat audacious resolution. I suspect that a great number of us have similar stories how Bengt has had a major influence on our lives, whether on the professional or personal level. Perhaps Bengt's most outstanding characteristic is his enthralling enthusiasm. This is equally true whether he is pondering some scientific conundrum, supervising students or performing in front of an audience, be it an

  1. Origins of Stellar Halos

    Science.gov (United States)

    Johnston, Kathryn V.

    2016-08-01

    This contribution reviews ideas about the origins of stellar halos. It includes discussion of the theoretical understanding of and observational evidence for stellar populations formed ``in situ'' (meaning formed in orbits close to their current ones), ``kicked-out'' (meaning formed in the inner galaxy in orbits unlike their current ones) and ``accreted'' (meaning formed in a dark matter halo other than the one they currently occupy). At this point there is general agreement that a significant fraction of any stellar halo population is likely ``accreted''. There is modest evidence for the presence of a ``kicked-out'' population around both the Milky Way and M31. Our theoretical understanding of and the observational evidence for an ``in situ'' population are less clear.

  2. Las Campanas Stellar Library

    Science.gov (United States)

    Chilingarian, Igor; Zolotukhin, Ivan; Beletsky, Yuri; Worthey, Guy

    2015-08-01

    Stellar libraries are fundamental tools required to understand stellar populations in star clusters and galaxies as well as properties of individual stars. Comprehensive libraries exist in the optical domain, but the near-infrared (NIR) domain stays a couple of decades behind. Here we present the Las Campanas Stellar Library project aiming at obtaining high signal-to-noise intermediate-resolution (R=8000) NIR spectra (0.83libraries, INDO-US and UVES-POP and followed up about 400 non-variable stars in the NIR in order to get complete optical-NIR coverage. Worth mentioning that our current sample includes about 80 AGB stars and a few dozens of bulge/LMC/SMC stars.

  3. Introduction to stellar structure

    CERN Document Server

    Maciel, Walter J

    2016-01-01

    In the first part of this book, the author presents the basic properties of the stellar interior and describes them thoroughly, along with deriving the main stellar structure equations of temperature, density, pressure and luminosity, among others. The process and application of solving these equations is explained, as well as linking these results with actual observations.  The second part of the text describes what happens to a star over time, and how to determine this by solving the same equations at different points during a star’s lifetime. The fate of various stars is quite different depending on their masses, and this is described in the final parts of the book. This text can be used for an upper level undergraduate course or an introductory graduate course on stellar physics.

  4. Wearable inertial sensors in swimming motion analysis: a systematic review.

    Science.gov (United States)

    de Magalhaes, Fabricio Anicio; Vannozzi, Giuseppe; Gatta, Giorgio; Fantozzi, Silvia

    2015-01-01

    The use of contemporary technology is widely recognised as a key tool for enhancing competitive performance in swimming. Video analysis is traditionally used by coaches to acquire reliable biomechanical data about swimming performance; however, this approach requires a huge computational effort, thus introducing a delay in providing quantitative information. Inertial and magnetic sensors, including accelerometers, gyroscopes and magnetometers, have been recently introduced to assess the biomechanics of swimming performance. Research in this field has attracted a great deal of interest in the last decade due to the gradual improvement of the performance of sensors and the decreasing cost of miniaturised wearable devices. With the aim of describing the state of the art of current developments in this area, a systematic review of the existing methods was performed using the following databases: PubMed, ISI Web of Knowledge, IEEE Xplore, Google Scholar, Scopus and Science Direct. Twenty-seven articles published in indexed journals and conference proceedings, focusing on the biomechanical analysis of swimming by means of inertial sensors were reviewed. The articles were categorised according to sensor's specification, anatomical sites where the sensors were attached, experimental design and applications for the analysis of swimming performance. Results indicate that inertial sensors are reliable tools for swimming biomechanical analyses.

  5. Silicon-micromachined accelerometers for space inertial systems

    Science.gov (United States)

    Saha, I.; Islam, R.; Kanakaraju, K.; Jain, Yashwant K.; Alex, T. K.

    1999-11-01

    Accelerometers are key components of various motion control systems ranging in use from inertial guidance of rockets and satellite launch vehicles to safety applications in the automotive industry. The accelerometers that are used for spare inertial systems are characterized by high resolution, small bandwidth, large working range and excellent linearity. Current advances in this field are based on silicon micromachining. Silicon bulk and surface micromachined accelerometers offer advantages of reduced size and weight, less power consumption and the use of a fabrication process derived form an already well established semiconductor fab technology. Of the various approaches to silicon micromachined accelerometers, two are in a well advanced state of development. The first is the capacitive force balanced type and the second the piezoresistive type. The capacitive approach has the advantage of higher stability and resolution and lower temperature coefficients. But it requires proximal detection circuitry to prevent parasitics to overwhelm the circuit. A new approach reported recently uses a silicon micromachined cantilever beam which acts as a Fabry Perot interferometer when light form an optical fiber is impinged on it. In this paper we overview all the approaches and try to select a suitable candidate for use in space borne inertial systems.

  6. Sparse field stellar photometry.

    Science.gov (United States)

    Reid, N.

    The past few years have seen substantial developments in the capability of high speed measuring machines in the field of automated stellar photometry. In this review, after describing some of the limitations on photometric precision, empirical results are used to demonstrate the sort of accuracies that are possible with the UK Schmidt plate plus COSMOS/APM images-scan combination. The astronomical results obtained to date from these machines are discussed, and some consideration is given to the future role of measuring machines in stellar astronomy.

  7. Gravitational Lensing & Stellar Dynamics

    CERN Document Server

    Koopmans, L V E

    2005-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and mass-anisotropy degeneracies. Second, observational results are presented from the Lenses Structure & Dynamics (LSD) Survey and the Sloan Lens ACS (SLACS) Survey collaborations to illustrate this new methodology in constraining the dark and stellar density profiles, and mass structure, of early-type galaxies to redshifts of unity.

  8. Spectral gaps, inertial manifolds and kinematic dynamos

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Manuel [Departamento de Analisis Matematico, Universidad de Valladolid, 47005 Valladolid (Spain)]. E-mail: mnjmhd@am.uva.es

    2005-10-17

    Inertial manifolds are desirable objects when ones wishes a dynamical process to behave asymptotically as a finite-dimensional ones. Recently [Physica D 194 (2004) 297] these manifolds are constructed for the kinematic dynamo problem with time-periodic velocity. It turns out, however, that the conditions imposed on the fluid velocity to guarantee the existence of inertial manifolds are too demanding, in the sense that they imply that all the solutions tend exponentially to zero. The inertial manifolds are meaningful because they represent different decay rates, but the classical dynamos where the magnetic field is maintained or grows are not covered by this approach, at least until more refined estimates are found.

  9. Optical technologies for space sensor

    Science.gov (United States)

    Wang, Hu; Liu, Jie; Xue, Yaoke; Liu, Yang; Liu, Meiying; Wang, Lingguang; Yang, Shaodong; Lin, Shangmin; Chen, Su; Luo, Jianjun

    2015-10-01

    Space sensors are used in navigation sensor fields. The sun, the earth, the moon and other planets are used as frame of reference to obtain stellar position coordinates, and then to control the attitude of an aircraft. Being the "eyes" of the space sensors, Optical sensor system makes images of the infinite far stars and other celestial bodies. It directly affects measurement accuracy of the space sensor, indirectly affecting the data updating rate. Star sensor technology is the pilot for Space sensors. At present more and more attention is paid on all-day star sensor technology. By day and night measurements of the stars, the aircraft's attitude in the inertial coordinate system can be provided. Facing the requirements of ultra-high-precision, large field of view, wide spectral range, long life and high reliability, multi-functional optical system, we integration, integration optical sensors will be future space technology trends. In the meantime, optical technologies for space-sensitive research leads to the development of ultra-precision optical processing, optical and precision test machine alignment technology. It also promotes the development of long-life optical materials and applications. We have achieved such absolute distortion better than ±1um, Space life of at least 15years of space-sensitive optical system.

  10. Inertial Confinement Fusion Materials Science

    Energy Technology Data Exchange (ETDEWEB)

    Hamza, A V

    2004-06-01

    Demonstration of thermonuclear ignition and gain on a laboratory scale is one of science's grand challenges. The National Ignition Facility (NIF) is committed to achieving inertial confinement fusion (ICF) by 2010. Success in this endeavor depends on four elements: the laser driver performance, target design, experimental diagnostics performance, and target fabrication and target materials performance. This article discusses the current state of target fabrication and target materials performance. The first three elements will only be discussed insofar as they relate to target fabrication specifications and target materials performance. Excellent reviews of the physics of ICF are given by Lindl [Lindl 1998] and Lindl et al. [Lindl 2004]. To achieve conditions under which inertial confinement is sufficient to achieve thermonuclear burn, an imploded fuel capsule is compressed to conditions of high density and temperature. In the laboratory a driver is required to impart energy to the capsule to effect an implosion. There are three drivers currently being considered for ICF in the laboratory: high-powered lasers, accelerated heavy ions, and x rays resulting from pulsed power machines. Of these, high-powered lasers are the most developed, provide the most symmetric drive, and provide the most energy. Laser drive operates in two configurations. The first is direct drive where the laser energy impinges directly on the ICF capsule and drives the implosion. The second is indirect drive, where the energy from the laser is first absorbed in a high-Z enclosure or hohlraum surrounding the capsule, and the resulting x-rays emitted by the hohlraum material drives the implosion. Using direct drive the laser beam energy is absorbed by the electrons in the outer corona of the target. The electrons transport the energy to the denser shell region to provide the ablation and the resulting implosion. Laser direct drive is generally less efficient and more hydrodynamically unstable

  11. Gravitational lensing & stellar dynamics

    NARCIS (Netherlands)

    Koopmans, L. V. E.; Mamon, GA; Combes, F; Deffayet, C; Fort, B

    2006-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and mass-ani

  12. Few period quasisymmetric stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Isaev, M.Y.; Mikhailov, M.I.; Shafranov, V.D.; Subbotin, A.A. [Russian Research Centre `Kurchatov Institute`, Moscow (Russian Federation); Cooper, W.A. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP); Medvedev, S.Y. [Keldysh Inst. of Applied Mathematics, Russian Academy of Sciences, Moscow (Russian Federation)

    1997-06-01

    The results of plasma equilibrium and local stability investigations in two and four-period quasisymmetric stellarators are presented. A near-axis approximation is used for 2-period systems and the 3D codes VMEC and TERPSICHORE are used for four-periods devices to optimise the configurations. (author) 4 figs., 8 refs.

  13. Gravitational lensing & stellar dynamics

    NARCIS (Netherlands)

    Koopmans, L. V. E.; Mamon, GA; Combes, F; Deffayet, C; Fort, B

    2006-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and

  14. Stellar magnetic cycles

    Science.gov (United States)

    Baliunas, S. L.

    2004-05-01

    Is hope for understanding the solar magnetic cycle to be found in stars? Observations of stars with significant sub-surface convective zones -- masses smaller than about 1.5 solar masses on the lower main sequence and many types of cool, post-main-sequence stars -- indicate the presence of surface and atmospheric inhomogeneities analogous to solar magnetic features, making stellar magnetic activity a cosmically widespread phenomenon. Observations have been made primarily in visible wavelengths, and important information has also been derived from the ultraviolet and x-ray spectrum regions. Interannual to interdecadal variability of spectrum indicators of stellar magnetic features is common, and in some cases similar in appearance to the 11-year sunspot cycle. Successful models of the physical processes responsible for stellar magnetic cycles, typically cast as a magnetohydrodynamic dynamo, require advances in understanding not only convection but also the magnetic field's interaction with it. The observed facts that underpin the hope for models will be summarized. Properties of stellar magnetic cycles will be compared and contrasted with those of the sun, including inferences from paleo-environmental reservoirs that contain information on solar century- to millennial-scale magnetic variability. Partial support of this research came from NASA NAG5-7635, NRC COBASE, CRDF 322, MIT-MSG 5710001241, JPL 1236821, AF 49620-02-1-0194, Richard Lounsberry Foundation, Langley-Abbot, Rollins, Scholarly Studies and James Arthur Funds (Smithsonian Institution) and several generous individuals.

  15. Stellar Structure and Evolution

    CERN Document Server

    Kippenhahn, Rudolf; Weiss, Achim

    2013-01-01

    This long-awaited second edition of the classical textbook on Stellar Structure and Evolution by Kippenhahn and Weigert is a thoroughly revised version of the original text. Taking into account modern observational constraints as well as additional physical effects such as mass loss and diffusion, Achim Weiss and Rudolf Kippenhahn have succeeded in bringing the book up to the state-of-the-art with respect to both the presentation of stellar physics and the presentation and interpretation of current sophisticated stellar models. The well-received and proven pedagogical approach of the first edition has been retained. The book provides a comprehensive treatment of the physics of the stellar interior and the underlying fundamental processes and parameters. The models developed to explain the stability, dynamics and evolution of the stars are presented and great care is taken to detail the various stages in a star’s life. Just as the first edition, which remained a standard work for more than 20 years after its...

  16. Gravitational lensing & stellar dynamics

    NARCIS (Netherlands)

    Koopmans, L. V. E.; Mamon, GA; Combes, F; Deffayet, C; Fort, B

    2006-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and mass-ani

  17. Time and Relative Distance Inertial Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Precise location information is critical for crewmembers for safe EVA Moon and Mars exploration. Current inertial navigation systems are too bulky, fragile, and...

  18. One possible interaction-inertial interaction

    CERN Document Server

    Yang, Xuejun

    2012-01-01

    Proposed in this paper is a possible interaction which exists in nature - inertial interaction. It gives matter an inertia and inertial mass. The formula of inertial mass has been derived. It is possible that inertial interaction leads to the redshifts of quasars, the rotation curve of spiral galaxy, the accelerating expansion of the universe, and the stronger gravitational lens effects of quasars, galaxies, or clusters of galaxies. Einstein's Gravitational Equation has been modified. Gravitational redshift, perihelion precession, and bending of light in spherically symmetric vacuum gravitational field are calculated. The differential equations of static spherically symmetric star's internal evolution are given. The accelerating expansion stage of the universe evolution equations are derived. The evolution of the universe is periodic. Time does not have an origin. There is no Big Bang. Although there is divergent singularity, there is no universe's singularity of incomplete geodesic. There are no horizon prob...

  19. Inertial Upper Stage Thermal Test Program

    Science.gov (United States)

    1989-04-12

    REPORT SD-TR-89-26 Inertial Upper Stage Thermal Test Program D. J. SPENCER and H. A. BIXLER Aerophysics Laboratory Laboratory Operations The...TITLE (Include Security Classification) Inertial Upper Stage Thermal Test Program 12. PERSONAL AUTHOR(S) Spencer, Donald J., and Bixler, Henry A. 13a...by the laboratory thermal test program under consideration here. Details of the IUS launch vehicle characteristics and corrective action taken in

  20. Segregation of helicity in inertial wave packets

    Science.gov (United States)

    Ranjan, A.

    2017-03-01

    Inertial waves are known to exist in the Earth's rapidly rotating outer core and could be important for the dynamo generation. It is well known that a monochromatic inertial plane wave traveling parallel to the rotation axis (along positive z ) has negative helicity while the wave traveling antiparallel (negative z ) has positive helicity. Such a helicity segregation, north and south of the equator, is necessary for the α2-dynamo model based on inertial waves [Davidson, Geophys. J. Int. 198, 1832 (2014), 10.1093/gji/ggu220] to work. The core is likely to contain a myriad of inertial waves of different wave numbers and frequencies. In this study, we investigate whether this characteristic of helicity segregation also holds for an inertial wave packet comprising waves with the same sign of Cg ,z, the z component of group velocity. We first derive the polarization relations for inertial waves and subsequently derive the resultant helicity in wave packets forming as a result of superposition of two or more waves. We find that the helicity segregation does hold for an inertial wave packet unless the wave numbers of the constituent waves are widely separated. In the latter case, regions of opposite color helicity do appear, but the mean helicity retains the expected sign. An illustration of this observation is provided by (a) calculating the resultant helicity for a wave packet formed by superposition of four upward-propagating inertial waves with different wave vectors and (b) conducting the direct numerical simulation of a Gaussian eddy under rapid rotation. Last, the possible effects of other forces such as the viscous dissipation, the Lorentz force, buoyancy stratification, and nonlinearity on helicity are investigated and discussed. The helical structure of the wave packet is likely to remain unaffected by dissipation or the magnetic field, but can be modified by the presence of linearly stable stratification and nonlinearity.

  1. The NIM Inertial Mass Measurement Project

    CERN Document Server

    Li, Shisong; He, Qing; Li, Zhengkun; Zhao, Wei; Han, Bing; Lu, Yunfeng

    2014-01-01

    An inertial mass measurement project, which is expected to precisely measure the Planck constant, $h$, for possible comparisons with known gravitational mass measurement projects, e.g., the watt balance and the Avogadro project, is being carried out at the National Institute of Metrology, China. The principle, apparatus, and experimental investigations of the inertial mass measurement are presented. The prototype of the experiment and the Planck constant with relative uncertainty of several parts in $10^{4}$ have been achieved for principle testing.

  2. Bubble-Driven Inertial Micropump

    CERN Document Server

    Torniainen, Erik D; Markel, David P; Kornilovitch, Pavel E

    2012-01-01

    The fundamental action of the bubble-driven inertial micropump is investigated. The pump has no moving parts and consists of a thermal resistor placed asymmetrically within a straight channel connecting two reservoirs. Using numerical simulations, the net flow is studied as a function of channel geometry, resistor location, vapor bubble strength, fluid viscosity, and surface tension. Two major regimes of behavior are identified: axial and non-axial. In the axial regime, the drive bubble either remains inside the channel or continues to grow axially when it reaches the reservoir. In the non-axial regime the bubble grows out of the channel and in all three dimensions while inside the reservoir. The net flow in the axial regime is parabolic with respect to the hydraulic diameter of the channel cross-section but in the non-axial regime it is not. From numerical modeling, it is determined that the net flow is maximal when the axial regime crosses over to the non-axial regime. To elucidate the basic physical princi...

  3. Computational Design of Short Pulse Laser Driven Iron Opacity Measurements at Stellar-Relevant Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madison E. [Univ. of Florida, Gainesville, FL (United States)

    2017-05-20

    Opacity is a critical parameter in the simulation of radiation transport in systems such as inertial con nement fusion capsules and stars. The resolution of current disagreements between solar models and helioseismological observations would bene t from experimental validation of theoretical opacity models. Overall, short pulse laser heated iron experiments reaching stellar-relevant conditions have been designed with consideration of minimizing tamper emission and optical depth effects while meeting plasma condition and x-ray emission goals.

  4. Stellar populations in star clusters

    CERN Document Server

    Li, Chengyuan; Deng, Licai

    2016-01-01

    Stellar populations contain the most important information about star clus- ter formation and evolution. Until several decades ago, star clusters were believed to be ideal laboratories for studies of simple stellar populations (SSPs). However, discoveries of multiple stellar populations in Galactic globular clusters have expanded our view on stellar populations in star clusters. They have simultaneously generated a number of controversies, particularly as to whether young star clusters may have the same origin as old globular clusters. In addition, extensive studies have revealed that the SSP scenario does not seem to hold for some intermediate-age and young star clusters either, thus making the origin of multiple stellar populations in star clusters even more complicated. Stellar population anomalies in numerous star clusters are well-documented, implying that the notion of star clusters as true SSPs faces serious challenges. In this review, we focus on stellar populations in massive clusters with different ...

  5. Microinstabilities in stellarator plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rafiq, T.; Nasim, M.H.; Persson, M. [Department of Electromagnetics and Euratom/VR Association, Chalmers University of Technology, Goeteborg (Sweden)

    2003-07-01

    Linear stability and localization of ion temperature gradient modes in fully 3-dimensional stellarator plasmas is calculated in the electrostatic limit. A ballooning mode formalism with WKB assumption is applied to reduce the equations into ordinary differential equation along the field lines which are solved numerically for different plasma parameters. The results are correlated with the geometrical effects such as magnetic curvature, local magnetic shear and its integrated value along the field line and the effects of trapped electrons are also investigated. The eigenfunctions of the most unstable modes are found to be localized but the nodes in the amplitude of the eigenfunctions may be large depending upon the location on the magnetic surface. The results are compared and contrasted with calculations in tokamak geometry and the implications on future stellarator design is also discussed. (orig.)

  6. Inertial response from wind turbines

    Science.gov (United States)

    Moore, Ian F.

    Wind power is an essential part of the strategy to address challenges facing the energy sector. Operation of the electricity network in 2020 will require higher levels of response and reserve from generation. The provision of inertial response from wind turbines was investigated. A model was developed for the simulation of frequency on the mainland UK system, including a simplified model for a synchronous generator to represent Full Power Converter turbines. Two different methods of inertia response, the step method and the inertia coupling method, were modelled and introduced into the turbine torque speed control. Simulations illustrated the effects on primary frequency control for a high penetration of wind turbines. Results are shown for different demand levels with generation losses of 1320GW and 1800GW. A comparison of the inertia functions is included and the effect of wind speed and the constant speed region of the maximum power extraction curve. For the scenarios modelled only a small change in turbine output was required for inertia response (0.02p.u). Without inertia response a large increase in synchronous plant response was needed. A test rig was constructed consisting of a Full Power Converter bridge and a synchronous generator driven by a dc machine. Power converters were designed and constructed by the candidate. Vector control of both the generator converter and grid converter was implemented on a dedicated control platform. The inertia coupling function was implemented and a test frequency deviation injected to represent a load generation imbalance. Results compared closely to those from the model and demonstrated the capability to closely couple turbine speed to system frequency with adjustment of the response via a filter if desired. The experimental work confirmed the adequacy of the simplified generator model and further confirmed the possibility of using inertia response. The inertia coupling function was considered suitable for use for the UK

  7. DOLPHOT: Stellar photometry

    Science.gov (United States)

    Dolphin, Andrew

    2016-08-01

    DOLPHOT is a stellar photometry package that was adapted from HSTphot for general use. It supports two modes; the first is a generic PSF-fitting package, which uses analytic PSF models and can be used for any camera. The second mode uses ACS PSFs and calibrations, and is effectively an ACS adaptation of HSTphot. A number of utility programs are also included with the DOLPHOT distribution, including basic image reduction routines.

  8. The DEMO Quasisymmetric Stellarator

    OpenAIRE

    McFadden, Geoffrey B.; Garabedian, Paul R.

    2010-01-01

    The NSTAB nonlinear stability code solves differential equations in conservation form, and the TRAN Monte Carlo test particle code tracks guiding center orbits in a fixed background, to provide simulations of equilibrium, stability, and transport in tokamaks and stellarators. These codes are well correlated with experimental observations and have been validated by convergence studies. Bifurcated 3D solutions of the 2D tokamak problem have been calculated that model persistent disruptions, neo...

  9. Oscillations in stellar superflares

    CERN Document Server

    Balona, L A; Kosovichev, A; Nakariakov, V M; Pugh, C E; Van Doorsselaere, T

    2015-01-01

    Two different mechanisms may act to induce quasi-periodic pulsations (QPP) in whole-disk observations of stellar flares. One mechanism may be magneto-hydromagnetic (MHD) forces and other processes acting on flare loops as seen in the Sun. The other mechanism may be forced local acoustic oscillations due to the high-energy particle impulse generated by the flare (known as `sunquakes' in the Sun). We analyze short-cadence Kepler data of 257 flares in 75 stars to search for QPP in the flare decay branch or post-flare oscillations which may be attributed to either of these two mechanisms. About 18 percent of stellar flares show a distinct bump in the flare decay branch of unknown origin. The bump does not seem to be a highly-damped global oscillation because the periods of the bumps derived from wavelet analysis do not correlate with any stellar parameter. We detected damped oscillations covering several cycles (QPP), in seven flares on five stars. The periods of these oscillations also do not correlate with any ...

  10. Small Area Inertial Navigation Tracking (SAINT) System for Precise Location of Buried UXO

    Science.gov (United States)

    2008-01-01

    inertial navigation tracking system (SAINT) technology integrated with an EM61-HH metal detector . The primary objective of this demonstration was to...positioning reference frame. This demonstration highlighted the integration of SAINT with a standard EM61-HH metal detector . The primary objective was to

  11. Inertial Confinement Fusion Annual Report 1997

    Energy Technology Data Exchange (ETDEWEB)

    Correll, D

    1998-06-01

    The ICF Annual Report provides documentation of the achievements of the LLNL ICF Program during the fiscal year by the use of two formats: (1) an Overview that is a narrative summary of important results for the fiscal year and (2) a compilation of the articles that previously appeared in the ICF Quarterly Report that year. Both the Overview and Quarterly Report are also on the Web at http://lasers.llnl.gov/lasers/pubs/icfq.html. Beginning in Fiscal Year 1997, the fourth quarter issue of the ICF Quarterly was no longer printed as a separate document but rather included in the ICF Annual. This change provided a more efficient process of documenting our accomplishments with-out unnecessary duplication of printing. In addition we introduced a new document, the ICF Program Monthly Highlights. Starting with the September 1997 issue and each month following, the Monthly Highlights will provide a brief description of noteworthy activities of interest to our DOE sponsors and our stakeholders. The underlying theme for LLNL's ICF Program research continues to be defined within DOE's Defense Programs missions and goals. In support of these missions and goals, the ICF Program advances research and technology development in major interrelated areas that include fusion target theory and design, target fabrication, target experiments, and laser and optical science and technology. While in pursuit of its goal of demonstrating thermonuclear fusion ignition and energy gain in the laboratory, the ICF Program provides research and development opportunities in fundamental high-energy-density physics and supports the necessary research base for the possible long-term application of inertial fusion energy for civilian power production. ICF technologies continue to have spin-off applications for additional government and industrial use. In addition to these topics, the ICF Annual Report covers non-ICF funded, but related, laser research and development and associated

  12. Theory of inertial waves in rotating fluids

    Science.gov (United States)

    Gelash, Andrey; L'vov, Victor; Zakharov, Vladimir

    2017-04-01

    The inertial waves emerge in the geophysical and astrophysical flows as a result of Earth rotation [1]. The linear theory of inertial waves is known well [2] while the influence of nonlinear effects of wave interactions are subject of many recent theoretical and experimental studies. The three-wave interactions which are allowed by inertial waves dispersion law (frequency is proportional to cosine of the angle between wave direction and axes of rotation) play an exceptional role. The recent studies on similar type of waves - internal waves, have demonstrated the possibility of formation of natural wave attractors in the ocean (see [3] and references herein). This wave focusing leads to the emergence of strong three-wave interactions and subsequent flows mixing. We believe that similar phenomena can take place for inertial waves in rotating flows. In this work we present theoretical study of three-wave and four-wave interactions for inertial waves. As the main theoretical tool we suggest the complete Hamiltonian formalism for inertial waves in rotating incompressible fluids [4]. We study three-wave decay instability and then present statistical description of inertial waves in the frame of Hamiltonian formalism. We obtain kinetic equation, anisotropic wave turbulence spectra and study the problem of parametric wave turbulence. These spectra were previously found in [5] by helicity decomposition method. Taking this into account we discuss the advantages of suggested Hamiltonian formalism and its future applications. Andrey Gelash thanks support of the RFBR (Grant No.16-31-60086 mol_a_dk) and Dr. E. Ermanyuk, Dr. I. Sibgatullin for the fruitful discussions. [1] Le Gal, P. Waves and instabilities in rotating and stratified flows, Fluid Dynamics in Physics, Engineering and Environmental Applications. Springer Berlin Heidelberg, 25-40, 2013. [2] Greenspan, H. P. The theory of rotating fluids. CUP Archive, 1968. [3] Brouzet, C., Sibgatullin, I. N., Scolan, H., Ermanyuk, E

  13. Ultrasensitive Inertial and Force Sensors with Diamagnetically Levitated Magnets

    Science.gov (United States)

    Prat-Camps, J.; Teo, C.; Rusconi, C. C.; Wieczorek, W.; Romero-Isart, O.

    2017-09-01

    We theoretically show that a magnet can be stably levitated on top of a punctured superconductor sheet in the Meissner state without applying any external field. The trapping potential created by such induced-only superconducting currents is characterized for magnetic spheres ranging from tens of nanometers to tens of millimeters. Such a diamagnetically levitated magnet is predicted to be extremely well isolated from the environment. We propose to use it as an ultrasensitive force and inertial sensor. A magnetomechanical readout of its displacement can be performed by using superconducting quantum interference devices. An analysis using current technology shows that force and acceleration sensitivities on the order of 10-23 N /√{Hz } (for a 100-nm magnet) and 10-14 g /√{Hz } (for a 10-mm magnet) might be within reach in a cryogenic environment. Such remarkable sensitivities, both in force and acceleration, can be used for a variety of purposes, from designing ultrasensitive inertial sensors for technological applications (e.g., gravimetry, avionics, and space industry), to scientific investigations on measuring Casimir forces of magnetic origin and gravitational physics.

  14. Inertial-range spectrum of whistler turbulence

    Directory of Open Access Journals (Sweden)

    Y. Narita

    2010-02-01

    Full Text Available We develop a theoretical model of an inertial-range energy spectrum for homogeneous whistler turbulence. The theory is a generalization of the Iroshnikov-Kraichnan concept of the inertial-range magnetohydrodynamic turbulence. In the model the dispersion relation is used to derive scaling laws for whistler waves at highly oblique propagation with respect to the mean magnetic field. The model predicts an energy spectrum for such whistler waves with a spectral index −2.5 in the perpendicular component of the wave vector and thus provides an interpretation about recent discoveries of the second inertial-range of magnetic energy spectra at high frequencies in the solar wind.

  15. Foot mounted inertial system for pedestrian navigation

    Science.gov (United States)

    Godha, S.; Lachapelle, G.

    2008-07-01

    This paper discusses algorithmic concepts, design and testing of a system based on a low-cost MEMS-based inertial measurement unit (IMU) and high-sensitivity global positioning system (HSGPS) receivers for seamless personal navigation in a GPS signal degraded environment. The system developed here is mounted on a pedestrian shoe/foot and uses measurements based on the dynamics experienced by the inertial sensors on the user's foot. The IMU measurements are processed through a conventional inertial navigation system (INS) algorithm and are then integrated with HSGPS receiver measurements and dynamics derived constraint measurements using a tightly coupled integration strategy. The ability of INS to bridge the navigation solution is evaluated through field tests conducted indoors and in severely signal degraded forest environments. The specific focus is on evaluating system performance under challenging GPS conditions.

  16. The solar-stellar connection

    Science.gov (United States)

    Giampapa, Mark S.

    2016-07-01

    A review of some principal results achieved in the area of stellar astrophysics with its origins in solar physics - the Solar-Stellar Connection - is presented from the perspective of an observational astronomer. The historical origins of the Solar-Stellar Connection are discussed followed by a review of key results from observations of stellar cycles analogous to the solar cycle in terms of parameters relevant to dynamo theory. A review of facets of angular momentum evolution and irradiance variations, each of which is determined by emergent, dynamo-generated magnetic fields, is given. Recent considerations of the impacts of stellar magnetic activity on the ambient radiative and energetic particle environment of the habitable zone of exoplanet systems are summarized. Some anticipated directions of the Solar-Stellar Connection in the new era of astronomy as defined by the advent of transformative facilities are presented.

  17. Inertial Control of the VIRGO Superattenuator

    CERN Document Server

    Losurdo, G

    1999-01-01

    The VIRGO superattenuator (SA) is effective in depressing the seismic noise below the thermal noise level above 4 Hz. On the other hand, the residual mirror motion associated to the SA normal modes can saturate the dynamics of the interferometer locking system. This motion is reduced implementing a wideband (DC-5 Hz) multidimensional control (the so called inertial damping) which makes use of both accelerometers and position sensors and of a DSP system. Feedback forces are exerted by coil-magnet actuators on the top of the inverted pendulum. The inertial damping is successful in reducing the mirror motion within the requirements. The results are presented.

  18. Inertial manifold of the atmospheric equations

    Institute of Scientific and Technical Information of China (English)

    李建平; 丑纪范

    1999-01-01

    For a class of nonlinear evolution equations, their global attractors are studied and the existence of their inertial manifolds is discussed using the truncated method. Then, on the basis of the properties of operators of the atmospheric equations, it is proved that the operator equation of the atmospheric motion with dissipation and external forcing belongs to the class of nonlinear evolution equations. Therefore, it is known that there exists an inertial manifold of the atmospheric equations if the spectral gap condition for the dissipation operator is satisfied. These results furnish a basis for further studying the dynamical properties of global attractor of the atmospheric equations and for designing better numerical scheme.

  19. THE ADVANCED STELLAR COMPASS

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Liebe, Carl Christian

    1997-01-01

    The science objective of the Danish Geomagnetic Research Satellite "Ørsted" is to map the magnetic field of the Earth, with a vector precision of a fraction of a nanotesla. This necessitates an attitude reference instrument with a precision of a few arcseconds onboard the satellite. To meet...... this demand the Advanced Stellar Compass (ASC), a fully autonomous miniature star tracker, was developed. This ASC is capable of both solving the "lost in space" problem and determine the attitude with arcseconds precision. The development, principles of operation and instrument autonomy of the ASC...

  20. Stellar structure of magnetars

    Science.gov (United States)

    Dong, JianMin; Zuo, Wei; Gu, JianZhong; Shang, XinLe

    2016-04-01

    Magnetars are strong magnetized neutron stars which could emit quiescent X-ray, repeating burst of soft gamma ray, and even the giant flares. We investigate the effects of magnetic fields on the structure of isolated magnetars. The stellar structure together with the magnetic field configuration can be obtained at the same time within a self-consistent procedure. The magnetar mass and radius are found to be weakly enhanced by the strong magnetic fields. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars.

  1. Inertial Confinement Fusion R&D and Nuclear Proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Robert J. Goldston

    2011-04-28

    In a few months, or a few years, the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory may achieve fusion gain using 192 powerful lasers to generate x-rays that will compress and heat a small target containing isotopes of hydrogen. This event would mark a major milestone after decades of research on inertial confinement fusion (ICF). It might also mark the beginning of an accelerated global effort to harness fusion energy based on this science and technology. Unlike magnetic confinement fusion (ITER, 2011), in which hot fusion fuel is confined continuously by strong magnetic fields, inertial confinement fusion involves repetitive fusion explosions, taking advantage of some aspects of the science learned from the design and testing of hydrogen bombs. The NIF was built primarily because of the information it would provide on weapons physics, helping the United States to steward its stockpile of nuclear weapons without further underground testing. The U.S. National Academies' National Research Council is now hosting a study to assess the prospects for energy from inertial confinement fusion. While this study has a classified sub-panel on target physics, it has not been charged with examining the potential nuclear proliferation risks associated with ICF R&D. We argue here that this question urgently requires direct and transparent examination, so that means to mitigate risks can be assessed, and the potential residual risks can be balanced against the potential benefits, now being assessed by the NRC. This concern is not new (Holdren, 1978), but its urgency is now higher than ever before.

  2. The DEMO Quasisymmetric Stellarator

    Directory of Open Access Journals (Sweden)

    Geoffrey B. McFadden

    2010-02-01

    Full Text Available The NSTAB nonlinear stability code solves differential equations in conservation form, and the TRAN Monte Carlo test particle code tracks guiding center orbits in a fixed background, to provide simulations of equilibrium, stability, and transport in tokamaks and stellarators. These codes are well correlated with experimental observations and have been validated by convergence studies. Bifurcated 3D solutions of the 2D tokamak problem have been calculated that model persistent disruptions, neoclassical tearing modes (NTMs and edge localized modes (ELMs occurring in the International Thermonuclear Experimental Reactor (ITER, which does not pass the NSTAB simulation test for nonlinear stability. So we have designed a quasiaxially symmetric (QAS stellarator with similar proportions as a candidate for the demonstration (DEMO fusion reactor that does pass the test [1]. The configuration has two field periods and an exceptionally accurate 2D symmetry that furnishes excellent thermal confinement and good control of the prompt loss of alpha particles. Robust coils are found from a filtered form of the Biot-Savart law based on a distribution of current over a control surface for the coils and the current in the plasma defined by the equilibrium calculation. Computational science has addressed the issues of equilibrium, stability, and transport, so it remains to develop an effective plan to construct the coils and build a diverter.

  3. CHAOTIC DUFFING TYPE OSCILLATOR WITH INERTIAL DAMPING

    DEFF Research Database (Denmark)

    Tamaševicius, Arunas; Mykolaitis, Gytis; Kirvaitis, Raimundas

    2009-01-01

    A novel Duffing-Holmes type autonomous chaotic oscillator is described. In comparison with the well-known non-autonomous Duffing-Holmes circuit it lacks the external periodic drive, but includes two extra linear feedback sub-circuits, namely a direct positive feedback loop, and an inertial negative...

  4. Inertial Sensor Signals Denoising with Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Ioana-Raluca EDU

    2015-03-01

    Full Text Available In the current paper we propose a new software procedure for processing data from an inertial navigation system boarded on a moving vehicle, in order to achieve accurate navigation information on the displacement of the vehicle in terms of position, speed, acceleration and direction. We divided our research in three phases. In the first phase of our research, we implemented a real-time evaluation criterion with the intention of achieving real-time data from an accelerometer. It is well-known that most errors in the detection of position, velocity and attitude in inertial navigation occur due to difficult numerical integration of noise. In the second phase, we were interested in achieving a better estimation and compensation of the gyro sensor angular speed measurements. The errors of these sensors occur because of their miniaturization, they cannot be eliminated but can be modelled by applying specific signal processing methods. The objective of both studies was to propose a signal processing algorithm, based on Wavelet filter, along with a criterion for evaluating and updating the optimal decomposition level of Wavelet transform for achieving accurate information from inertial sensors. In the third phase of our work we are suggesting the utility of a new complex algorithm for processing data from an inertial measurement unit, containing both miniaturized accelerometers and gyros, after undergoing a series of numerical simulations and after obtaining accurate information on vehicle displacement

  5. Optical alignment of Centaur's inertial guidance system

    Science.gov (United States)

    Gordan, Andrew L.

    1987-01-01

    During Centaur launch operations the launch azimuth of the inertial platform's U-accelerometer input axis must be accurately established and maintained. This is accomplished by using an optically closed loop system with a long-range autotheodolite whose line of sight was established by a first-order survey. A collimated light beam from the autotheodolite intercepts a reflecting Porro prism mounted on the platform azimuth gimbal. Thus, any deviation of the Porro prism from its predetermined heading is optically detected by the autotheodolite. The error signal produced is used to torque the azimuth gimbal back to its required launch azimuth. The heading of the U-accelerometer input axis is therefore maintained automatically. Previously, the autotheodolite system could not distinguish between vehicle sway and rotational motion of the inertial platform unless at least three prisms were used. One prism was mounted on the inertial platform to maintain azimuth alignment, and two prisms were mounted externally on the vehicle to track sway. For example, the automatic azimuth-laying theodolite (AALT-SV-M2) on the Saturn vehilce used three prisms. The results of testing and modifying the AALT-SV-M2 autotheodolite to simultaneously monitor and maintain alignment of the inertial platform and track the sway of the vehicle from a single Porro prism.

  6. Enhanced Subsea Acoustically Aided Inertial Navigation

    DEFF Research Database (Denmark)

    Jørgensen, Martin Juhl

    This thesis deals with enhancing state-of-the-art underwater acoustic–inertial navigation systems that are necessary for deep water robotic operations. Throughout the project intelligent and simple operational solutions to complex real-world problems was emphasized. Offshore hydrocarbon, oil...

  7. Simulation Platform for Vision Aided Inertial Navigation

    Science.gov (United States)

    2014-09-18

    canyons, indoors or underground. It is also possible for a GPS signal to be jammed. This weakness motivates the development of alternate navigation ...Johnson, E. N., Magree, D., Wu, A., & Shein, A. (2013). "GPS‐Denied Indoor and Outdoor Monocular Vision Aided Navigation and Control of Unmanned...SIMULATION PLATFORM FOR VISION AIDED INERTIAL NAVIGATION THESIS SEPTEMBER 2014 Jason Gek

  8. Laboratory measurements of grain-bedrock interactions using inertial sensors.

    Science.gov (United States)

    Maniatis, Georgios; Hoey, Trevor; Hodge, Rebecca; Valyrakis, Manousos; Drysdale, Tim

    2016-04-01

    Sediment transport in steep mountain streams is characterized by the movement of coarse particles (diameter c.100 mm) over beds that are not fully sediment-covered. Under such conditions, individual grain dynamics become important for the prediction of sediment movement and subsequently for understanding grain-bedrock interaction. Technological advances in micro-mechanical-electrical systems now provide opportunities to measure individual grain dynamics and impact forces from inside the sediments (grain inertial frame of reference) instead of trying to infer them indirectly from water flow dynamics. We previously presented a new prototype sensor specifically developed for monitoring sediment transport [Maniatis et al. EGU 2014], and have shown how the definition of the physics of the grain using the inertial frame and subsequent derived measurements which have the potential to enhance the prediction of sediment entrainment [Maniatis et al. 2015]. Here we present the latest version of this sensor and we focus on beginning of the cessation of grain motion: the initial interaction with the bed after the translation phase. The sensor is housed in a spherical case, diameter 80mm, and is constructed using solid aluminum (density = 2.7 kg.m-3) after detailed 3D-CAD modelling. A complete Inertial Measurement Unit (a combination of micro- accelerometer, gyroscope and compass) was placed at the center of the mass of the assembly, with measurement ranges of 400g for acceleration, and 1200 rads/sec for angular velocity. In a 0.9m wide laboratory flume, bed slope = 0.02, the entrainment threshold of the sensor was measured, and the water flow was then set to this value. The sensor was then rolled freely from a static cylindrical bar positioned exactly on the surface of the flowing water. As the sensor enters the flow we record a very short period of transport (1-1.5 sec) followed by the impact on the channel bed. The measured Total Kinetic Energy (Joules) includes the

  9. Dual Matter-Wave Inertial Sensors in Weightlessness

    CERN Document Server

    Barrett, Brynle; Chichet, Laure; Battelier, Baptiste; Lévèque, Thomas; Landragin, Arnaud; Bouyer, Philippe

    2016-01-01

    Quantum technology based on cold-atom interferometers is showing great promise for fields such as inertial sensing and fundamental physics. However, the best precision achievable on Earth is limited by the free-fall time of the atoms, and their full potential can only be realized in Space where interrogation times of many seconds will lead to unprecedented sensitivity. Various mission scenarios are presently being pursued which plan to implement matter-wave inertial sensors. Toward this goal, we realize the first onboard operation of simultaneous $^{87}$Rb $-$ $^{39}$K interferometers in the weightless environment produced during parabolic flight. The large vibration levels ($10^{-2}~g/\\sqrt{\\rm Hz}$), acceleration range ($0-1.8~g$) and rotation rates ($5$ deg/s) during flight present significant challenges. We demonstrate the capability of our dual-quantum sensor by measuring the E\\"{o}tv\\"{o}s parameter with systematic-limited uncertainties of $1.1 \\times 10^{-3}$ and $3.0 \\times 10^{-4}$ during standard- a...

  10. Dual matter-wave inertial sensors in weightlessness

    Science.gov (United States)

    Barrett, Brynle; Antoni-Micollier, Laura; Chichet, Laure; Battelier, Baptiste; Lévèque, Thomas; Landragin, Arnaud; Bouyer, Philippe

    2016-12-01

    Quantum technology based on cold-atom interferometers is showing great promise for fields such as inertial sensing and fundamental physics. However, the finite free-fall time of the atoms limits the precision achievable on Earth, while in space interrogation times of many seconds will lead to unprecedented sensitivity. Here we realize simultaneous 87Rb-39K interferometers capable of operating in the weightless environment produced during parabolic flight. Large vibration levels (10-2 g Hz-1/2), variations in acceleration (0-1.8 g) and rotation rates (5° s-1) onboard the aircraft present significant challenges. We demonstrate the capability of our correlated quantum system by measuring the Eötvös parameter with systematic-limited uncertainties of 1.1 × 10-3 and 3.0 × 10-4 during standard- and microgravity, respectively. This constitutes a fundamental test of the equivalence principle using quantum sensors in a free-falling vehicle. Our results are applicable to inertial navigation, and can be extended to the trajectory of a satellite for future space missions.

  11. Stellar populations in star clusters

    Science.gov (United States)

    Li, Cheng-Yuan; de Grijs, Richard; Deng, Li-Cai

    2016-12-01

    Stellar populations contain the most important information about star cluster formation and evolution. Until several decades ago, star clusters were believed to be ideal laboratories for studies of simple stellar populations (SSPs). However, discoveries of multiple stellar populations in Galactic globular clusters have expanded our view on stellar populations in star clusters. They have simultaneously generated a number of controversies, particularly as to whether young star clusters may have the same origin as old globular clusters. In addition, extensive studies have revealed that the SSP scenario does not seem to hold for some intermediate-age and young star clusters either, thus making the origin of multiple stellar populations in star clusters even more complicated. Stellar population anomalies in numerous star clusters are well-documented, implying that the notion of star clusters as true SSPs faces serious challenges. In this review, we focus on stellar populations in massive clusters with different ages. We present the history and progress of research in this active field, as well as some of the most recent improvements, including observational results and scenarios that have been proposed to explain the observations. Although our current ability to determine the origin of multiple stellar populations in star clusters is unsatisfactory, we propose a number of promising projects that may contribute to a significantly improved understanding of this subject.

  12. Stellar Dymatics in 30 Doradus

    Directory of Open Access Journals (Sweden)

    Guillermo Bosch

    2001-01-01

    Full Text Available From multislit spectroscopy of 180 stars in the ionising cluster of 30 Doradus, we have obtained reliable stellar radial velocities for 58 stars. With these we calculated the stellar radial velocity dispersion and found it to be 35 km/s. If the cluster is dinamically relaxed the virial mass is ~ 1 × 107 Msolar

  13. A catalog of stellar spectrophotometry

    Science.gov (United States)

    Adelman, S. J.; Pyper, D. M.; Shore, S. N.; White, R. E.; Warren, W. H., Jr.

    1989-01-01

    A machine-readable catalog of stellar spectrophotometric measurements made with rotating grating scanner is introduced. Consideration is given to the processes by which the stellar data were collected and calibrated with the fluxes of Vega (Hayes and Latham, 1975). A sample page from the spectrophotometric catalog is presented.

  14. Wakes in Inertial Fusion Plasmas

    Science.gov (United States)

    Ellis, Ian Norman

    Plasma wave wakes, which are the collective oscillatory response near the plasma frequency to the propagation of particles or electromagnetic waves through a plasma, play a critical role in many plasma processes. New results from backwards stimulated Raman scattering (BSRS), in which wakes with phase velocities much less than the speed of light are induced by the beating of counter-propagating light waves, and from electron beam stopping, in which the wakes are produced by the motion of relativistically propagating electrons through the dense plasma, are discussed. Both processes play important roles in Inertial Confinement Fusion (ICF). In BSRS, laser light is scattered backwards out of the plasma, decreasing the energy available to compress the ICF capsule and affecting the symmetry of where the laser energy hits the hohlraum wall in indirect drive ICF. The plasma wave wake can also generate superthermal electrons that can preheat the core and/or the ablator. Electron beam stopping plays a critical role in the Fast Ignition (FI) ICF concept, in which a beam of relativistic electrons is used to heat the target core to ignition temperatures after the compression stage. The beam stopping power determines the effectiveness of the heating process. This dissertation covers new discoveries on the importance of plasma wave wakes in both BSRS and electron beam stopping. In the SRS studies, 1D particle-in-cell (PIC) simulations using OSIRIS are performed, which model a short-duration (˜500/ω0 --1FWHM) counter-propagating scattered light seed pulse in the presence of a constant pump laser with an intensity far below the absolute instability threshold for plasma waves undergoing Landau damping. The seed undergoes linear convective Raman amplification and dominates over the amplification of fluctuations due to particle discreteness. The simulation results are in good agreement with results from a coupled-mode solver when special relativity and the effects of finite size PIC

  15. The role of the National Ignition Facility in the development of inertial fusion energy

    Energy Technology Data Exchange (ETDEWEB)

    Logan, B.G.

    1996-06-01

    The authors have completed a conceptual design for a 1.8-MJ, 500-TW, 0.35-{mu}m solid-state laser system for the National Ignition Facility (NIF), which will demonstrate inertial fusion ignition and gain for national security, energy, and science applications. The technical goal of the U.S. Inertial Confinement Fusion (ICF) Program as stated in the current ICF Five-Year Program Plan is {open_quotes}to produce pure fusion ignition and burn in the laboratory, with fusion yields of 200 to 1000 MJ, in support of three missions: (1) to play an essential role in accessing physics regimes of interest in nuclear weapon design...; (2) to provide an above-ground simulation capability for nuclear weapon effects...; and (3) to develop inertial fusion energy for civilian power production.{close_quotes} This article addresses the third goal-- the development of inertial fusion energy (IFE). This article reports a variety of potential contributions the NIF could make to the development of IFE, drawn from a nationally attended workshop held at the University of California at Berkeley in Feb, 1994. In addition to demonstrating fusion ignition as a fundamental basis for IFE, the findings of the workshop, are that the NIF could also provide important data for target physics and fabrication technology, for IFE target chamber phenomena such as materials responses to target emissions, and for fusion power technology-relevant tests.

  16. Alaska Athabascan stellar astronomy

    Science.gov (United States)

    Cannon, Christopher M.

    2014-01-01

    Stellar astronomy is a fundamental component of Alaska Athabascan cultures that facilitates time-reckoning, navigation, weather forecasting, and cosmology. Evidence from the linguistic record suggests that a group of stars corresponding to the Big Dipper is the only widely attested constellation across the Northern Athabascan languages. However, instruction from expert Athabascan consultants shows that the correlation of these names with the Big Dipper is only partial. In Alaska Gwich'in, Ahtna, and Upper Tanana languages the Big Dipper is identified as one part of a much larger circumpolar humanoid constellation that spans more than 133 degrees across the sky. The Big Dipper is identified as a tail, while the other remaining asterisms within the humanoid constellation are named using other body part terms. The concept of a whole-sky humanoid constellation provides a single unifying system for mapping the night sky, and the reliance on body-part metaphors renders the system highly mnemonic. By recognizing one part of the constellation the stargazer is immediately able to identify the remaining parts based on an existing mental map of the human body. The circumpolar position of a whole-sky constellation yields a highly functional system that facilitates both navigation and time-reckoning in the subarctic. Northern Athabascan astronomy is not only much richer than previously described; it also provides evidence for a completely novel and previously undocumented way of conceptualizing the sky---one that is unique to the subarctic and uniquely adapted to northern cultures. The concept of a large humanoid constellation may be widespread across the entire subarctic and have great antiquity. In addition, the use of cognate body part terms describing asterisms within humanoid constellations is similarly found in Navajo, suggesting a common ancestor from which Northern and Southern Athabascan stellar naming strategies derived.

  17. Indoor inertial navigation application for smartphones with Android

    Science.gov (United States)

    Kamiński, Ł.; Tarapata, G.

    2015-09-01

    Inertial navigation is widely used by the military, in logistics and sailing. In mobile devices, inertial sensors are mostly used as a support for GPS and Wi-Fi-based navigation systems. Inertial-based navigation might prove useful on mobile devices running Android OS. At present, in spite of the accelerometer sensor's precision having been greatly improved, as well as the devices' computing power continuously rising, inertial navigation's precision still suffers. For smartphones, the key solution seems to be the usage of sensor fusion and signal smart filtering, both discussed in this paper. The paper also describes implementation of inertial navigation in Android devices, their analysis as well as test results.

  18. High volume air sampler for environmental nanoparticles using a sharp-cut inertial filter combined with an impactor

    Science.gov (United States)

    Zhang, Tong; Zhao, Tianren; Takahashi, Hideaki; Hata, Mitsuhiko; Toriba, Akira; Ikeda, Takuji; Otani, Yoshio; Furuuchi, Masami

    2017-02-01

    A multi-nozzle layered mesh inertial filter, developed by the authors based on inertial filter technology for separating ultrafine particles (UFPs) at a moderate pressure drop, was investigated in an attempt to improve the steepness of the separation efficiency curve by combining an inertial filter and an impactor. In this system, the separation curves overlap each other, while maintaining about a 100 nm difference in cutoff size d p50. Such a combination, which we refer to as a ‘hybrid inertial filter’, was validated for a single nozzle geometry. Using a multi nozzle geometry, it was scaled up to a high volume air sampling flow rate of 400 l min-1 at a pressure drop of  filter using multi-nozzle geometry was confirmed. The features of the hybrid inertial filter included the suppression of the bouncing of particles with sizes  >300 nm, a steeper collection efficiency curve and less pressure drop than those of a previous type of inertial filter. The ambient PM0.13 evaluated for the present unit was found to be in good agreement with values obtained for 2 different types of cascade air samplers.

  19. The Stellar Imager (SI) - A Mission to Resolve Stellar Surfaces, Interiors, and Magnetic Activity

    Science.gov (United States)

    Christensen-Dalsgaard, Jorgen; Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita

    2012-01-01

    The Stellar Imager (SI) is a space-based, UV/Optical Interferometer (UVOI) designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and of the Universe in general. It will also probe via asteroseismology flows and structures in stellar interiors. SI will enable the development and testing of a predictive dynamo model for the Sun, by observing patterns of surface activity and imaging of the structure and differential rotation of stellar interiors in a population study of Sun-like stars to determine the dependence of dynamo action on mass, internal structure and flows, and time. SI's science focuses on the role of magnetism in the Universe and will revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magnetohydrodynamically controlled processes in the Universe. SI is a "LandmarklDiscovery Mission" in the 2005 Heliophysics Roadmap, an implementation of the UVOI in the 2006 Astrophysics Strategic Plan, and a NASA Vision Mission ("NASA Space Science Vision Missions" (2008), ed. M. Allen). We present here the science goals of the SI Mission, a mission architecture that could meet those goals, and the technology development needed to enable this mission

  20. How does stellar irradiation make hot Jupiters puffy?

    Science.gov (United States)

    Wei, Yu-Jie; Gu, Pin-Gao

    2017-06-01

    Hot Jupiters appear to be re-inflated as their host stars evolve and become more luminous, shedding more light on the intriguing correlation between stellar irradiation and the size of hot Jupiters. To account for the phenomenon, one of the well-known models is the thermal-tide scenario proposed by Arras and Socrates. We present a linear analysis of semi-diurnal thermal tides in a hot Jupiter. The Coriolis effect is added to our equation, which generates more wave modes than non-rotating models, such as Rossby, Yanai, and inertial waves. We attempt to investigate where and which mode contributes most of the torque that maintains the planet in an asynchronous state against gravitational tides, leading to re-inflation of a hot Jupiter.

  1. Tracking Non-stellar Objects on Ground and in Space

    DEFF Research Database (Denmark)

    Riis, Troels; Jørgensen, John Leif

    1999-01-01

    Many space exploration missions require a fast, early and accurate detection of a specific target. E.g. missions to asteroids, x-ray source missions or interplanetary missions.A second generation star tracker may be used for accurate detection of non-stellar objects of interest for such missions...... approximately down to CCD magnitude mv 7.5), the objects thus listed will include galaxies, nebulae, planets, asteroids, comets and artefacts as satellites.The angular resolution in inertial reference coordinates is a few arcseconds, allowing quite accurate tracking of these objects. Furthermore, the objects...... are easily divided into two classes; Stationary (galaxies, nebulae etc.), and moving object (planets, asteroids, satellite etc.).For missions targeting moving objects, detection down to mv 11 is possible without any system impacts, simply by comparing lists of objects with regular intervals, leaving out all...

  2. Stellar Snowflake Cluster

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 Stellar Snowflake Cluster Combined Image [figure removed for brevity, see original site] Figure 2 Infrared Array CameraFigure 3 Multiband Imaging Photometer Newborn stars, hidden behind thick dust, are revealed in this image of a section of the Christmas Tree cluster from NASA's Spitzer Space Telescope, created in joint effort between Spitzer's infrared array camera and multiband imaging photometer instruments. The newly revealed infant stars appear as pink and red specks toward the center of the combined image (fig. 1). The stars appear to have formed in regularly spaced intervals along linear structures in a configuration that resembles the spokes of a wheel or the pattern of a snowflake. Hence, astronomers have nicknamed this the 'Snowflake' cluster. Star-forming clouds like this one are dynamic and evolving structures. Since the stars trace the straight line pattern of spokes of a wheel, scientists believe that these are newborn stars, or 'protostars.' At a mere 100,000 years old, these infant structures have yet to 'crawl' away from their location of birth. Over time, the natural drifting motions of each star will break this order, and the snowflake design will be no more. While most of the visible-light stars that give the Christmas Tree cluster its name and triangular shape do not shine brightly in Spitzer's infrared eyes, all of the stars forming from this dusty cloud are considered part of the cluster. Like a dusty cosmic finger pointing up to the newborn clusters, Spitzer also illuminates the optically dark and dense Cone nebula, the tip of which can be seen towards the bottom left corner of each image. This combined image shows the presence of organic molecules mixed with dust as wisps of green, which have been illuminated by nearby star formation. The larger yellowish dots neighboring the baby red stars in the Snowflake Cluster are massive stellar infants forming from the same cloud. The blue dots

  3. Torque for an Inertial Piezoelectric Rotary Motor

    Directory of Open Access Journals (Sweden)

    Jichun Xing

    2013-01-01

    Full Text Available For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor.

  4. Inertial-confinement fusion with lasers

    Science.gov (United States)

    Betti, R.; Hurricane, O. A.

    2016-05-01

    The quest for controlled fusion energy has been ongoing for over a half century. The demonstration of ignition and energy gain from thermonuclear fuels in the laboratory has been a major goal of fusion research for decades. Thermonuclear ignition is widely considered a milestone in the development of fusion energy, as well as a major scientific achievement with important applications in national security and basic sciences. The US is arguably the world leader in the inertial confinement approach to fusion and has invested in large facilities to pursue it, with the objective of establishing the science related to the safety and reliability of the stockpile of nuclear weapons. Although significant progress has been made in recent years, major challenges still remain in the quest for thermonuclear ignition via laser fusion. Here, we review the current state of the art in inertial confinement fusion research and describe the underlying physical principles.

  5. Extended inertial range phenomenology of magnetohydrodynamic turbulence

    Science.gov (United States)

    Matthaeus, William H.; Zhou, YE

    1989-01-01

    A phenomenological treatment of the inertial range of isotropic statistically steady magnetohydrodynamic turbulence is presented, extending the theory of Kraichnan (1965). The role of Alfven wave propagation is treated on equal footing with nonlinear convection, leading to a simple generalization of the relations between the times characteristic of wave propagation, convection, energy transfer, and decay of triple correlations. The theory leads to a closed-form steady inertial range spectral law that reduces to the Kraichnan and Kolmogorov laws in appropriate limits. The Kraichnan constant is found to be related in a simple way to the Kolmogorov constant; for typical values of the latter constant, the former has values in the range 1.22-1.87. Estimates of the time scale associated with spectral transfer of energy also emerge from the new approach, generalizing previously presented 'golden rules' for relating the spectral transfer time scale to the Alfven and eddy-turnover time scales.

  6. Tuning particle focusing in inertial microfluidic devices

    Science.gov (United States)

    Hood, Kaitlyn; Kahkeshani, Soroush; di Carlo, Dino; Roper, Marcus

    2014-11-01

    Particles in microfluidic devices at finite Reynolds number are subject to two forces: (i) inertial focusing and (ii) particle-particle interactions. Although microfluidic chips exploit these forces to manipulate particles for particle/cell sorting and high throughput flow cytometry, the forces are not understood well enough to allow rational design of devices that can tune and attenuate particle focusing. We present a mathematical model addressing both inertial focusing and particle interactions, and we apply our model to various channel geometries to determine the balance of forces. In addition, we present experimental data that illustrate the accuracy of our model. We will address the following questions: Why do high aspect ratio channels favor two equilibrium positions? Why do particle chains form?

  7. Advanced Stellar Compass - Proposal for the SMART-1 Project

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Betto, Maurizio; Kilsgaard, Søren

    1998-01-01

    This proposal is the DTU response to the Swedish Space Corporation (SSC) request for proposal (r.f.p.) for the SMART-1 star tracker.SMART-1 is a small ESA scientific and technological satellite planned to be launched in late 2001.The Advanced Stellar Compass (ASC) is a highly advanced and autonom......This proposal is the DTU response to the Swedish Space Corporation (SSC) request for proposal (r.f.p.) for the SMART-1 star tracker.SMART-1 is a small ESA scientific and technological satellite planned to be launched in late 2001.The Advanced Stellar Compass (ASC) is a highly advanced...... and autonomous Stellar Reference Unit designed, developed and produced by the Space Instrumentation Group of the Department of Automation of the Technical University of Denmark.The document is structured as follows. First we present the ASC - heritage, system description, performance - then we address more...

  8. Dynamic Accuracy of Inertial Magnetic Sensor Modules

    Science.gov (United States)

    2016-12-01

    interpolate function to replace the repeating values to ensure the RMS value was only calculated with the ground truth data obtained directly from...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) Magnetic, angular rate, and gravity (MARG) sensor modules have extensive applications in inertial...and gravity , MARG, micro-electro-mechanical systems, MEMS, quaternion 15. NUMBER OF PAGES 147 16. PRICE CODE 17. SECURITY CLASSIFICATION OF

  9. Membrane-less microfiltration using inertial microfluidics

    OpenAIRE

    Majid Ebrahimi Warkiani; Andy Kah Ping Tay; Guofeng Guan; Jongyoon Han

    2015-01-01

    Microfiltration is a ubiquitous and often crucial part of many industrial processes, including biopharmaceutical manufacturing. Yet, all existing filtration systems suffer from the issue of membrane clogging, which fundamentally limits the efficiency and reliability of the filtration process. Herein, we report the development of a membrane-less microfiltration system by massively parallelizing inertial microfluidics to achieve a macroscopic volume processing rates (~ 500 mL/min). We demonstra...

  10. Precise laser gyroscope for autonomous inertial navigation

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, A G; Molchanov, A V; Izmailov, E A [Joint Stock Company ' Moscow Institute of Electromechanics and Automatics' , Moscow (Russian Federation); Chirkin, M V [Ryazan State Radio Engineering University (Russian Federation)

    2015-01-31

    Requirements to gyroscopes of strapdown inertial navigation systems for aircraft application are formulated. The construction of a ring helium – neon laser designed for autonomous navigation is described. The processes that determine the laser service life and the relation between the random error of the angular velocity measurement and the surface relief features of the cavity mirrors are analysed. The results of modelling one of the promising approaches to processing the laser gyroscope signals are presented. (laser gyroscopes)

  11. Towards a Wearable Inertial Sensor Network

    OpenAIRE

    Van Laerhoven, Kristof; Gellersen, Hans; Kern, Nicky; Schiele, Bernt

    2003-01-01

    Abstract. Wearable inertial sensors have become an inexpensive option to measure the movements and positions of a person. Other techniques that use environmental sensors such as ultrasound trackers or vision-based methods need full line of sight or a local setup, and it is complicated to access this data from a wearable computer’s perspective. However, a body-centric approach where sensor data is acquired and processed locally, has a need for appropriate algorithms that have to operate under ...

  12. Inertial Focusing of Microparticles in Curvilinear Microchannels

    Science.gov (United States)

    Özbey, Arzu; Karimzadehkhouei, Mehrdad; Akgönül, Sarp; Gozuacik, Devrim; Koşar, Ali

    2016-12-01

    A passive, continuous and size-dependent focusing technique enabled by “inertial microfluidics”, which takes advantage of hydrodynamic forces, is implemented in this study to focus microparticles. The objective is to analyse the decoupling effects of inertial forces and Dean drag forces on microparticles of different sizes in curvilinear microchannels with inner radius of 800 μm and curvature angle of 280°, which have not been considered in the literature related to inertial microfluidics. This fundamental approach gives insight into the underlying physics of particle dynamics and offers continuous, high-throughput, label-free and parallelizable size-based particle separation. Our design allows the same footprint to be occupied as straight channels, which makes parallelization possible with optical detection integration. This feature is also useful for ultrahigh-throughput applications such as flow cytometers with the advantages of reduced cost and size. The focusing behaviour of 20, 15 and 10 μm fluorescent polystyrene microparticles was examined for different channel Reynolds numbers. Lateral and vertical particle migrations and the equilibrium positions of these particles were investigated in detail, which may lead to the design of novel microfluidic devices with high efficiency and high throughput for particle separation, rapid detection and diagnosis of circulating tumour cells with reduced cost.

  13. Asteroseismic stellar activity relations

    CERN Document Server

    Bonanno, A; Karoff, C

    2014-01-01

    In asteroseismology an important diagnostic of the evolutionary status of a star is the small frequency separation which is sensitive to the gradient of the mean molecular weight in the stellar interior. It is thus interesting to discuss the classical age-activity relations in terms of this quantity. Moreover, as the photospheric magnetic field tends to suppress the amplitudes of acoustic oscillations, it is important to quantify the importance of this effect by considering various activity indicators. We propose a new class of age-activity relations that connects the Mt. Wilson $S$ index and the average scatter in the light curve with the small frequency separation and the amplitude of the p-mode oscillations. We used a Bayesian inference to compute the posterior probability of various empirical laws for a sample of 19 solar-like active stars observed by the Kepler telescope. We demonstrate the presence of a clear correlation between the Mt. Wilson $S$ index and the relative age of the stars as indicated by ...

  14. Stellar dynamics and black holes

    Indian Academy of Sciences (India)

    David Merritt

    2011-07-01

    Chandrasekhar’s most important contribution to stellar dynamics was the concept of dynamical friction. I briefly review that work, then discuss some implications of Chandrasekhar’s theory of gravitational encounters for motion in galactic nuclei.

  15. Stellar activity and magnetic shielding

    CERN Document Server

    Grießmeier, J -M; Lammer, H; Grenfell, J L; Stadelmann, A; Motschmann, U; 10.1017/S1743921309992961

    2010-01-01

    Stellar activity has a particularly strong influence on planets at small orbital distances, such as close-in exoplanets. For such planets, we present two extreme cases of stellar variability, namely stellar coronal mass ejections and stellar wind, which both result in the planetary environment being variable on a timescale of billions of years. For both cases, direct interaction of the streaming plasma with the planetary atmosphere would entail servere consequences. In certain cases, however, the planetary atmosphere can be effectively shielded by a strong planetary magnetic field. The efficiency of this shielding is determined by the planetary magnetic dipole moment, which is difficult to constrain by either models or observations. We present different factors which influence the strength of the planetary magnetic dipole moment. Implications are discussed, including nonthermal atmospheric loss, atmospheric biomarkers, and planetary habitability.

  16. The Milky Way's Stellar Disk

    CERN Document Server

    Rix, Hans-Walter

    2013-01-01

    A suite of vast stellar surveys mapping the Milky Way, culminating in the Gaia mission, is revolutionizing the empirical information about the distribution and properties of stars in the Galactic stellar disk. We review and lay out what analysis and modeling machinery needs to be in place to test mechanisms of disk galaxy evolution and to stringently constrain the Galactic gravitational potential, using such Galactic star-by-star measurements. We stress the crucial role of stellar survey selection functions in any such modeling; and we advocate the utility of viewing the Galactic stellar disk as made up from `mono-abundance populations' (MAPs), both for dynamical modeling and for constraining the Milky Way's evolutionary processes. We review recent work on the spatial and kinematical distribution of MAPs, and lay out how further study of MAPs in the Gaia era should lead to a decisively clearer picture of the Milky Way's dark matter distribution and formation history.

  17. Turbulence optimisation in stellarator experiments

    Energy Technology Data Exchange (ETDEWEB)

    Proll, Josefine H.E. [Max-Planck/Princeton Center for Plasma Physics (Germany); Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstr. 1, 17491 Greifswald (Germany); Faber, Benjamin J. [HSX Plasma Laboratory, University of Wisconsin-Madison, Madison, WI 53706 (United States); Helander, Per; Xanthopoulos, Pavlos [Max-Planck/Princeton Center for Plasma Physics (Germany); Lazerson, Samuel A.; Mynick, Harry E. [Plasma Physics Laboratory, Princeton University, P.O. Box 451 Princeton, New Jersey 08543-0451 (United States)

    2015-05-01

    Stellarators, the twisted siblings of the axisymmetric fusion experiments called tokamaks, have historically suffered from confining the heat of the plasma insufficiently compared with tokamaks and were therefore considered to be less promising candidates for a fusion reactor. This has changed, however, with the advent of stellarators in which the laminar transport is reduced to levels below that of tokamaks by shaping the magnetic field accordingly. As in tokamaks, the turbulent transport remains as the now dominant transport channel. Recent analytical theory suggests that the large configuration space of stellarators allows for an additional optimisation of the magnetic field to also reduce the turbulent transport. In this talk, the idea behind the turbulence optimisation is explained. We also present how an optimised equilibrium is obtained and how it might differ from the equilibrium field of an already existing device, and we compare experimental turbulence measurements in different configurations of the HSX stellarator in order to test the optimisation procedure.

  18. Red supergiants and stellar evolution

    CERN Document Server

    Ekström, Sylvia; Meynet, Georges; Groh, Jose; Granada, Anahí

    2013-01-01

    We review the significant role played by red supergiants (RSGs) in stellar populations, and some challenges and questions they raise for theoretical stellar evolution. We present how metallicity and rotation modify the way stars go to the red part of the Hertzsprung- Russell diagram or come back from it, and how RSGs might keep a trace of their main-sequence evolution. We compare theoretical popu- lation ratios with observed ones.

  19. A Highly Miniaturized Inertial Grade Gyroscope for Space Applications

    Science.gov (United States)

    Wiberg, D. V.; Challoner, A. D.; Shcheglov, K.; Hayworth, K.; Bae, S.; Yee, K.; Blaes, B.; DAgostino, S.; Stock, T.

    2001-01-01

    The evolution of inertial grade gyroscopes for space applications represents well over 50 years of technology development and an investment of hundreds of millions of dollars. The workhorse product which represents the current state-of-the art for commercially available high performance devices is the Litton-Hemishperical Resonator Gyro (HRG) Inertial Measurement Unit (IMU). This product has a performance figure of merit of 0.003 deg/hr bias drift, a volume of 567 cubic inches, weighs 19 pounds, draws about 30 watts and costs over 1 million each. Clearly devices of this magnitude are not conducive to the minimized mass, volume, power, and cost constraints of outer planet missions. An approach to breaking these potential barriers is the use of Microelectromechanical Systems (MEMS) based inertial devices. Although substantially reduced in size, mass power and cost, this approach has produced devices in the tactical performance range of greater than 1 deg/hour bias drift. This level of performance satisfies the preponderance of high market volume requirements such as automotive and tactical munitions but does not meet the limited market quantity requirements for the high precision space based market. Because of the very limited size of the space based market, there is little economic incentive for commercial fabricators of tactical grade devices to address the necessary performance improvements. The Jet Propulsion Laboratory (JPL) in conjunction with Boeing Space Systems (BSS) is addressing this void to satisfy our mutual requirements in this area. The project objective to is to achieve 0.01 deg/hr performance in an IMU which is less than 10 cubic inches in volume, weighs less than 0.5 pounds, draws less than 1 watt and is available in volume production for less than 2500. Reductions of this magnitude will be mission enabling capabilities for a variety of anticipated outer planet mission attributes such as autonomous control and docking, formation flying and robotic

  20. Integration and Testing of the Inertial Sensor for LISA Pathfinder mission

    Science.gov (United States)

    Sarra, Paolo

    High-precision technologies are essential for space-borne gravitational wave observatory, but full on-ground testing is not feasible. The ESA (European Space Agency) mission LISA Pathfinder (LPF) is aimed to perform in-flight verification of these key technologies, among them the Inertial Sensor, also known as Gravitational Reference Sensor (GRS). The core of the Inertial Sensor is the gravitational reference test mass: a cube of 46 mm made of Au/Pt used as mirror of the LPF interferometer. The “free floating” test mass is surrounded by a capacitive sensor providing the information to perform the “drag-free” control loop required to keep the spacecraft centred with respect to some fiducial points. The Inertial Sensor is equipped with two mechanisms. The caging and venting mechanism lock the test mass during on-ground activities and at launch. It also open the valve for Inertial Sensor venting to space. The grabbing, positioning and release mechanism controls the test mass during in-flight operational phases from caged to free-floating condition. Charge control of the free floating test mass is performed by illuminating its surface, or the electrodes surfaces, with UV light. The Inertial Sensor is equipped with optical fibers and feed-throughs for UV photons supply. Another key component of the Inertial Sensor is the balance mass. Balance masses are required to null the self-gravitational fields seen by the test mass. The test mass, the sensing electrodes, the mechanisms, the balance masses and the UV optical fibers are accommodated inside a dedicated high-vacuum chamber. The vacuum chamber is maintained in static vacuum during on-ground phase an then vented to space to provide the required in-flight vacuum environment around the test mass. A challenging alignment accuracy is required for the manufacturing, assembly and integration of the various equipment composing the Inertial Sensor. In particular for the test mass and the capacitance sensor micron level

  1. Gyroscopic Inertial Micro-Balance Azimuth Locator (GIMBAL) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Research Support Instruments, Inc. (RSI) proposes the Gyroscopic Inertial Micro-Balance Azimuth Locator (GIMBAL) program to use an innovative encapsulated spinning...

  2. INERTIAL ALGORITHMS FOR THE STATIONARY NAVIER-STOKES EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Hou Yanren(侯延仁); R.M.M. Mattheij

    2003-01-01

    Several kind of new numerical schemes for the stationary Navier-Stokes equa-tions based on the virtue of Inertial Manifold and Approximate Inertial Manifold, whichwe call them inertial algorithms in this paper, together with their error estimations are pre-sented. All these algorithms are constructed under an uniform frame, that is to constructsome kind of new projections for the Sobolev space in which the true solution is sought.It is shown that the proposed inertial algorithms can greatly improve the convergence rateof the standard Galerkin approximate solution with lower computing effort. And somenumerical examples are also given to verify results of this paper.

  3. Utilization of Practice Session Average Inertial Load to Quantify College Football Injury Risk.

    Science.gov (United States)

    Wilkerson, Gary B; Gupta, Ashish; Allen, Jeff R; Keith, Clay M; Colston, Marisa A

    2016-09-01

    Wilkerson, GB, Gupta, A, Allen, JR, Keith, CM, and Colston, MA. Utilization of practice session average inertial load to quantify college football injury risk. J Strength Cond Res 30(9): 2369-2374, 2016-Relatively few studies have investigated the potential injury prevention value of data derived from recently developed wearable technology for measurement of body mass accelerations during the performance of sport-related activities. The available evidence has been derived from studies focused on avoidance of overtraining syndrome, which is believed to induce a chronically fatigued state that can be identified through monitoring of inertial load accumulation. Reduced variability in movement patterns is also believed to be an important injury risk factor, but no evidence currently exists to guide interpretation of data derived from inertial measurement units (IMUs) in this regard. We retrospectively analyzed archived data for a cohort of 45 National Collegiate Athletic Association Division 1-football bowl subdivision football players who wore IMUs on the upper back during practice sessions to quantify any associations between average inertial load measured during practice sessions and occurrence of musculoskeletal sprains and strains. Both the coefficient of variation for average inertial load and frequent exposure to game conditions were found to be strongly associated with injury occurrence. Having either or both of the 2 risk factors provided strong discrimination between injured and noninjured players (χ = 9.048; p = 0.004; odds ratio = 8.04; 90% CI: 2.39, 27.03). Our findings may facilitate identification of individual football players who are likely to derive the greatest benefit from training activities designed to reduce injury risk through improved adaptability to rapidly changing environmental demands.

  4. Distributed chaos and inertial ranges in turbulence

    CERN Document Server

    Bershadskii, A

    2016-01-01

    It is shown that appearance of inertial range of scales, adjacent to distributed chaos range, results in adiabatic invariance of an energy correlation integral for isotropic homogeneous turbulence and for buoyancy driven turbulence (with stable or unstable stratification, including Rayleigh-Taylor mixing zone). Power spectrum of velocity field for distributed chaos dominated by this adiabatic invariant has a stretched exponential form $\\propto \\exp(-k/k_{\\beta})^{3/5}$. Results of recent direct numerical simulations have been used in order to support these conclusions.

  5. Fault tolerant highly reliable inertial navigation system

    Science.gov (United States)

    Jeerage, Mahesh; Boettcher, Kevin

    This paper describes a development of failure detection and isolation (FDI) strategies for highly reliable inertial navigation systems. FDI strategies are developed based on the generalized likelihood ratio test (GLRT). A relationship between detection threshold and false alarm rate is developed in terms of the sensor parameters. A new method for correct isolation of failed sensors is presented. Evaluation of FDI performance parameters, such as false alarm rate, wrong isolation probability, and correct isolation probability, are presented. Finally a fault recovery scheme capable of correcting false isolation of good sensors is presented.

  6. Diamond Ablators for Inertial Confinement Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Biener, J; Mirkarimi, P B; Tringe, J W; Baker, S L; Wang, Y M; Kucheyev, S O; Teslich, N E; Wu, K J; Hamza, A V; Wild, C; Woerner, E; Koidl, P; Bruehne, K; Fecht, H

    2005-06-21

    Diamond has a unique combination of physical properties for the inertial confinement fusion ablator application, such as appropriate optical properties, high atomic density, high yield strength, and high thermal conductivity. Here, we present a feasible concept to fabricate diamond ablator shells. The fabrication of diamond capsules is a multi-step process, which involves diamond chemical vapor deposition on silicon mandrels followed by polishing, microfabrication of holes, and removing of the silicon mandrel by an etch process. We also discuss the pros and cons of coarse-grained optical quality and nanocrystalline chemical vapor deposition diamond films for the ablator application.

  7. Application of inertial sensors for motion analysis

    Directory of Open Access Journals (Sweden)

    Ferenc Soha

    2012-06-01

    Full Text Available This paper presents our results on the application of various inertial sensors for motion analysis. After the introduction of different sensor types (accelerometer, gyroscope, magnetic field sensor, we discuss the possible data collection and transfer techniques using embedded signal processing and wireless data communication methods [1,2]. Special consideration is given to the interpretation of accelerometer readings, which contains both the static and dynamic components, and is affected by the orientation and rotation of the sensor. We will demonstrate the possibility to decompose these components for quasiperiodic motions. Finally we will demonstrate the application of commercially available devices (Wii sensor, Kinect sensor, mobile phone for motion analysis applications.

  8. Planets, stars and stellar systems

    CERN Document Server

    Bond, Howard; McLean, Ian; Barstow, Martin; Gilmore, Gerard; Keel, William; French, Linda

    2013-01-01

    This is volume 3 of Planets, Stars and Stellar Systems, a six-volume compendium of modern astronomical research covering subjects of key interest to the main fields of contemporary astronomy. This volume on “Solar and Stellar Planetary Systems” edited by Linda French and Paul Kalas presents accessible review chapters From Disks to Planets, Dynamical Evolution of Planetary Systems, The Terrestrial Planets, Gas and Ice Giant Interiors, Atmospheres of Jovian Planets, Planetary Magnetospheres, Planetary Rings, An Overview of the Asteroids and Meteorites, Dusty Planetary Systems and Exoplanet Detection Methods. All chapters of the handbook were written by practicing professionals. They include sufficient background material and references to the current literature to allow readers to learn enough about a specialty within astronomy, astrophysics and cosmology to get started on their own practical research projects. In the spirit of the series Stars and Stellar Systems published by Chicago University Press in...

  9. Accelerated Fitting of Stellar Spectra

    CERN Document Server

    Ting, Yuan-Sen; Rix, Hans-Walter

    2016-01-01

    Stellar spectra are often modeled and fit by interpolating within a rectilinear grid of synthetic spectra to derive the stars' labels: stellar parameters and elemental abundances. However, the number of synthetic spectra needed for a rectilinear grid grows exponentially with the label space dimensions, precluding the simultaneous and self-consistent fitting of more than a few elemental abundances. Shortcuts such as fitting subsets of parameters separately can introduce unknown systematics and do not produce correct error covariances in the derived labels. In this paper we present a new approach -- CHAT (Convex Hull Adaptive Tessellation) -- which includes several new ideas for inexpensively generating a sufficient stellar synthetic library, using linear algebra and the concept of an adaptive, data-driven grid. A convex hull approximates the region where the data lie in the label space. A variety of tests with mock datasets demonstrate that CHAT can reduce the number of required synthetic model calculations by...

  10. Seismological challenges for stellar structure

    CERN Document Server

    Christensen-Dalsgaard, J

    2010-01-01

    Helioseismology has provided very detailed information about the solar interior, and extensive data on a large number of stars, although at less detail, are promised by the ongoing and upcoming asteroseismic projects. In the solar case there remain serious challenges in understanding the inferred solar structure, particularly in the light of the revised determinations of the solar surface composition. Also, a secure understanding of the origins of solar rotation as inferred from helioseismology, both in the radiative interior and in the convection zone, is still missing. In the stellar case challenges are certain to appear as the data allow more detailed inferences of the properties of stellar cores. Large remaining uncertainties in modelling concerns the properties of convective cores and other processes that may cause mixing. As a result of developing asteroseismic signatures addressing these and other issues, we can look forward to a highly challenging, and hence exciting, era of stellar astrophysics.

  11. Antimicrobial screening of Mnium stellare

    Directory of Open Access Journals (Sweden)

    Kerem Canli

    2015-06-01

    Full Text Available Many plants contain active substances that are known to be effective in both enhancing the wound healing process and lowering the incidence of wound infections. Previous studies have shown that bryophytes produce a variety of secondary metabolites that present pharmaceutical activities including antimicrobial activity against various pathogenic bacteria and fungi. The aim of this study was to investigate the antimicrobial activity of Mnium stellare against 17 bacterial and 1 fungal strains. Our present study has shown that the ethanol extract of M. stellare has antimicrobial activity against several Gram positive and Gram negative microorganism tested, but its antimicrobial activity is notable especially against B. subtilis, S. typhimirium, S. aureus, S. carnosus, and S. epidermidis. These results are the very first report of the antimicrobial activity of M. stellare.

  12. Cold-atom Inertial Sensor without Deadtime

    CERN Document Server

    Fang, Bess; Savoie, Denis; Venon, Bertrand; Alzar, Carlos L Garrido; Geiger, Remi; Landragin, Arnaud

    2016-01-01

    We report the operation of a cold-atom inertial sensor in a joint interrogation scheme, where we simultaneously prepare a cold-atom source and operate an atom interferometer in order to eliminate dead times. Noise aliasing and dead times are consequences of the sequential operation which is intrinsic to cold-atom atom interferometers. Both phenomena have deleterious effects on the performance of these sensors. We show that our continuous operation improves the short-term sensitivity of atom interferometers, by demonstrating a record rotation sensitivity of $100$ nrad.s$^{-1}/\\sqrt{\\rm Hz}$ in a cold-atom gyroscope of $11$ cm$^2$ Sagnac area. We also demonstrate a rotation stability of $1$ nrad.s$^{-1}$ after $10^4$ s of integration, improving previous results by an order of magnitude. We expect that the continuous operation will allow cold-atom inertial sensors with long interrogation time to reach their full sensitivity, determined by the quantum noise limit.

  13. Contributions on Laser Driven Inertial Confinement Fusion

    Directory of Open Access Journals (Sweden)

    Heinrich Hora

    2005-01-01

    Full Text Available The following modified preprint of a chapter in the forthcoming book by Guillermo Velarde and Natividad Carpintero Santamaria Inertial Confinement Nuclear Fusion: A Historical Approach by its Pioneers with personal comments is presented here as an example about the long years difficult developments towards the aim for producing unlimited, safe and clean nuclear energy in the same way as it is the energy source of the sun. There are arguments that the most recent developments with the plasma block ignition using petawatt-picosecond laser pulses may lead to a fusion power station with a highly simplified operation such that the cost of electricity may be three or more times lower than any energy source on earth, opening the golden age with dramatic consequences for human life and the environment. Applied sciences in all fields, economics and politics may be stimulated just by considering these consequences though these new results on Inertial Fusion Energy (IFE need to be further examined and developed on a broad basis.

  14. Review of the Inertial Fusion Energy Program

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2004-03-29

    Igniting fusion fuel in the laboratory remains an alluring goal for two reasons: the desire to study matter under the extreme conditions needed for fusion burn, and the potential of harnessing the energy released as an attractive energy source for mankind. The inertial confinement approach to fusion involves rapidly compressing a tiny spherical capsule of fuel, initially a few millimeters in radius, to densities and temperatures higher than those in the core of the sun. The ignited plasma is confined solely by its own inertia long enough for a significant fraction of the fuel to burn before the plasma expands, cools down and the fusion reactions are quenched. The potential of this confinement approach as an attractive energy source is being studied in the Inertial Fusion Energy (IFE) program, which is the subject of this report. A complex set of interrelated requirements for IFE has motivated the study of novel potential solutions. Three types of “drivers” for fuel compression are presently studied: high-averagepower lasers (HAPL), heavy-ion (HI) accelerators, and Z-Pinches. The three main approaches to IFE are based on these drivers, along with the specific type of target (which contains the fuel capsule) and chamber that appear most promising for a particular driver.

  15. Inertial instrument system for aerial surveying

    Science.gov (United States)

    Brown, R.H.; Chapman, W.H.; Hanna, W.F.; Mongan, C.E.; Hursh, J.W.

    1985-01-01

    An inertial guidance system for aerial surveying has been developed under contract to the U.S. Geological Survey. This prototype system, known as the aerial profiling of terrain (APT) system, is designed to determine continuously the positions of points along an aircraft flight path, or the underlying terrain profile, to an accuracy of + or - 0.5 ft (15 cm) vertically and + or - 2 ft (61 cm) horizontally. The system 's objective thus is to accomplish, from a fixed-wing aircraft, what would traditionally be accomplished from ground-based topographic surveys combined with aerial photography and photogrammetry. The two-part strategy for measuring the terrain profile entails: (1) use of an inertial navigator for continuous determination of the three-coordinate position of the aircraft, and (2) use of an eye-safe pulsed laser profiler for continuous measurement of the vertical distance from aircraft to land surface, so that the desired terrain profile can then be directly computed. The APT system, installed in a DeHavilland Twin Otter aircraft, is typically flown at a speed of 115 mph (105 knots) at an altitude of 2,000 ft (610 m) above the terrain. Performance-evaluation flights have shown that the vertical and horizontal accuracy specifications are met. (USGS)

  16. Gyroscopes for Orientation and Inertial Navigation Systems

    Directory of Open Access Journals (Sweden)

    Radovan Marjanović Kavanagh

    2007-05-01

    Full Text Available In this paper the main elements of gyro-theodolites and inertial navigation systems are provided. The main function principles of mechanical gyros are explained and the main difficulties in maintenance and sources of errors while measuring with gyros and gyro-theodolites are listed. The principles of RLG and FOG gyros and the principles of inertial navigation are explained. The main differences of a guided platform and a strap-down system are explained. A brief review of mathematical expressions for position coordinate- determination from double integration of acceleration measurements from accelerometers is given. It is indicated on difficulties in INS application during a long time period caused by insufficient knowledge of gravity acceleration due to locally gravity anomalies and gyro-drift. The necessity of INS signal correction using another positioning system like GNSS is pointed out, applying Kalman filter algorithms for interpolation between two measuring points so as position prediction of points which are not measured. 

  17. Deriving stellar inclination of slow rotators using stellar activity

    CERN Document Server

    Dumusque, X

    2014-01-01

    Stellar inclination is an important parameter for many astrophysical studies. Although different techniques allow us to estimate stellar inclinationt for fast rotators, it becomes much more difficult when stars are rotating slower than $\\sim2$-2.5 \\kms. By using the new activity simulation SOAP 2.0 that can reproduce the photometric and spectroscopic variations induced by stellar activity, we are able to fit observations of solar-type stars and derive their inclination. For HD189733, we estimate the stellar inclination to be $i=84^{+6}_{-20}$ degrees, which implies a star-planet obliquity of $\\psi=4^{+18}_{-4}$ considering previous measurements of the spin-orbit angle. For $\\alpha$ Cen B, we derive an inclination of $i=45^{+9}_{-19}$, which implies that the rotational spin of the star is not aligned with the orbital spin of the $\\alpha$ Cen binary system. In addition, assuming that $\\alpha$ Cen Bb is aligned with its host star, no transit would occur. The inclination of $\\alpha$ Cen B can be measured using 40...

  18. Synthetic stellar mass-to-light ratios for stellar populations

    CERN Document Server

    Maraston, C

    1998-01-01

    Evolutionary synthesis models for stellar populations of various ages and chemical compositions are constructed with the approach described in Maraston (1998), in which the Fuel Consumption Theorem is used to evaluate the energetics of Post Main Sequence stars. We present here the synthetic `stellar' mass-to-light ratios (M*/L) in the U,B,V,R,I,J,H,K photometric bands, as functions of age and chemical composition, for single burst populations. Taking into account the contribution by stellar dead remnants, the computed M*/L ratios can be directly compared to those measured in early-type galaxies. The dependence of M*/L ratios on the IMF slope is also explored. The most interesting result is that the M*/L_B ratio of a 15 Gyr stellar population is found to increase by nearly a factor of three, when the chemical composition rises from [Fe/H] \\sim -0.5 to [Fe/H] \\sim +0.3. This impacts on the interpretation of the tilt of the Fundamental Plane of cluster ellipticals in the B band.

  19. Deriving stellar inclination of slow rotators using stellar activity

    Energy Technology Data Exchange (ETDEWEB)

    Dumusque, X., E-mail: xdumusque@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2014-12-01

    Stellar inclination is an important parameter for many astrophysical studies. Although different techniques allow us to estimate stellar inclination for fast rotators, it becomes much more difficult when stars are rotating slower than ∼2-2.5 km s{sup –1}. By using the new activity simulation SOAP 2.0 which can reproduce the photometric and spectroscopic variations induced by stellar activity, we are able to fit observations of solar-type stars and derive their inclination. For HD 189733, we estimate the stellar inclination to be i=84{sub −20}{sup +6} deg, which implies a star-planet obliquity of ψ=4{sub −4}{sup +18} considering previous measurements of the spin-orbit angle. For α Cen B, we derive an inclination of i=45{sub −19}{sup +9}, which implies that the rotational spin of the star is not aligned with the orbital spin of the α Cen binary system. In addition, assuming that α Cen Bb is aligned with its host star, no transit would occur. The inclination of α Cen B can be measured using 40 radial-velocity measurements, which is remarkable given that the projected rotational velocity of the star is smaller than 1.15 km s{sup –1}.

  20. ERROR ANALYSIS FOR INERTIAL GRAVIMETRY BY USE OF GNSS/SINS COMBINATION%GNSS/SINS组合进行惯性重力测量误差分析

    Institute of Scientific and Technical Information of China (English)

    柴华; 王勇; 王虎彪; 梁星辉

    2011-01-01

    As focusing on present domestic INS technology and GNSS data processing technology, the feasibility for carrying out inertial gravimetry experiment with domestic inertial navigation system is discussed. The results from the analysis show that, although GNSS observation and data processing have not big issues presently, it is still hard to reach 1 × 10-5ms-2 gravity accuracy by use of the inertial navigation system. However, with the technical progress of the domestic inertial system, the day for inertial gravimetry with domestic inertial navigation system is approaching.%针对INS技术及GNSS数据处理技术,分析中国实现惯性重力测量的可能性.分析结果表明,目前中国GNSS观测与数据处理技术用于惯性重力测量已不存在技术上的困难,而国产惯性测量系统的性能指标要达到1×10 -5ms-2的重力观测精度虽有一定的困难,但随着惯性测量系统技术的进步,利用国内研制的捷联式惯导与GNSS联合进行惯性重力测量已成为可能.

  1. Integrated micro-electro-mechanical sensor development for inertial applications

    Energy Technology Data Exchange (ETDEWEB)

    Allen, J.J.; Kinney, R.D.; Sarsfield, J. [and others

    1998-04-01

    Electronic sensing circuitry and micro electro mechanical sense elements can be integrated to produce inertial instruments for applications unheard of a few years ago. This paper will describe the Sandia M3EMS fabrication process, inertial instruments that have been fabricated, and the results of initial characterization tests of micro-machined accelerometers.

  2. Inertial Force Coupling to Nonlinear Aeroelasticity of Flexible Wing Aircraft

    Science.gov (United States)

    Nguyen, Nhan T.; Ting, Eric

    2016-01-01

    This paper investigates the inertial force effect on nonlinear aeroelasticity of flexible wing aircraft. The geometric are nonlinearity due to rotational and tension stiffening. The effect of large bending deflection will also be investigated. Flutter analysis will be conducted for a truss-braced wing aircraft concept with tension stiffening and inertial force coupling.

  3. Dispersion of (light) inertial particles in stratified turbulence

    NARCIS (Netherlands)

    van Aartrijk, M.; Clercx, H.J.H.; Armenio, Vincenzo; Geurts, Bernardus J.; Fröhlich, Jochen

    2010-01-01

    We present a brief overview of a numerical study of the dispersion of particles in stably stratified turbulence. Three types of particles arc examined: fluid particles, light inertial particles ($\\rho_p/\\rho_f = \\mathcal{O}(1)$) and heavy inertial particles ($\\rho_p/\\rho_f \\gg 1$). Stratification

  4. The dynamics of small inertial particles in weakly stratified turbulence

    NARCIS (Netherlands)

    van Aartrijk, M.; Clercx, H.J.H.

    We present an overview of a numerical study on the small-scale dynamics and the large-scale dispersion of small inertial particles in stably stratified turbulence. Three types of particles are examined: fluid particles, light inertial particles (with particle-to-fluid density ratio 1Ͽp/Ͽf25) and

  5. Investigations on inertial confinement fusion at the Russian Federal Nuclear Center - VNIIEF

    Energy Technology Data Exchange (ETDEWEB)

    Garanin, S; Kirillov, G A; Kochemasov, G G; Mkhitaryan, L S; Murugov, V M; Sukharev, S A; Zhidkov, N V [Institute for Laser Physics Researches, Russian Federal Nuclear Center - VNIIEF, 37 Prospect Mira, Sarov, Nizhnii Novgorod Reg., 607190 (Russian Federation)

    2003-12-01

    Since 30 years already, the All-Russia Institute of Experimental Physics (VNIIEF) is engaged in investigations on the problem of inertial confinement fusion. The high-power laser facilities 'Iskra 5' (Kirillov G A et al 1990 Laser Particle Beams 8 827-31) and 'Luch' (Sukharev S A 3rd Int. Conf. on Solid State Lasers for Application to Inertial Confinement Fusion ed W H Lowdermilk Proc. SPIE 3492 12-24) were created and are operating now in the framework of this programme. The main lines of the work at these facilities are the investigation of the physics of thermonuclear targets and the development of laser technologies. This work resulted in the development of a project of the new generation facility 'Iskra-6'. This report presents the main results of these works carried out at Russian Federal Nuclear Center - VNIIEF in the period 1991-2002.

  6. Index of light ion inertial confinement fusion publications and presentations January 1989 through December 1993

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, M.A. [ed.

    1995-11-01

    This report lists publications and presentations that are related to inertial confinement fusion and were authored or coauthored by Sandians in the Pulsed Power Sciences Center from 1989 through 1993. The 661 publications and presentations are categorized into the following general topics: (1) reviews, (2) ion sources, (3) ion diodes, (4) plasma opening switches, (5) ion beam transport, (6) targets and deposition physics, (7) advanced driver and pulsed power technology development, (8) diagnostics, and (9) code development. Research in these areas is arranged by topic in chronological order, with the early efforts under each topic presented first. The work is also categorized alphabetically by first author. A list of acronyms, abbreviations, and definitions of use in understanding light ion inertial confinement fusion research is also included.

  7. Poster Abstract: Automatic Calibration of Device Attitude in Inertial Measurement Unit Based Traffic Probe Vehicles

    KAUST Repository

    Mousa, Mustafa

    2016-04-28

    Probe vehicles consist in mobile traffic sensor networks that evolve with the flow of vehicles, transmitting velocity and position measurements along their path, generated using GPSs. To address the urban positioning issues of GPSs, we propose to replace them with inertial measurement units onboard vehicles, to estimate vehicle location and attitude using inertial data only. While promising, this technology requires one to carefully calibrate the orientation of the device inside the vehicle to be able to process the acceleration and rate gyro data. In this article, we propose a scheme that can perform this calibration automatically by leveraging the kinematic constraints of ground vehicles, and that can be implemented on low-end computational platforms. Preliminary testing shows that the proposed scheme enables one to accurately estimate the actual accelerations and rotation rates in the vehicle coordinates. © 2016 IEEE.

  8. The Additional Error of Inertial Sensors Induced by Hypersonic Flight Conditions.

    Science.gov (United States)

    Karachun, Volodimir; Mel'nick, Viktorij; Korobiichuk, Igor; Nowicki, Michał; Szewczyk, Roman; Kobzar, Svitlana

    2016-02-26

    The emergence of hypersonic technology pose a new challenge for inertial navigation sensors, widely used in aerospace industry. The main problems are: extremely high temperatures, vibration of the fuselage, penetrating acoustic radiation and shock N-waves. The nature of the additional errors of the gyroscopic inertial sensor with hydrostatic suspension components under operating conditions generated by forced precession of the movable part of the suspension due to diffraction phenomena in acoustic fields is explained. The cause of the disturbing moments in the form of the Coriolis inertia forces during the transition of the suspension surface into the category of impedance is revealed. The boundaries of occurrence of the features on the resonance wave match are described. The values of the "false" angular velocity as a result of the elastic-stress state of suspension in the acoustic fields are determined.

  9. The effect of static pressure on the inertial cavitation threshold.

    Science.gov (United States)

    Bader, Kenneth B; Raymond, Jason L; Mobley, Joel; Church, Charles C; Felipe Gaitan, D

    2012-08-01

    The amplitude of the acoustic pressure required to nucleate a gas or vapor bubble in a fluid, and to have that bubble undergo an inertial collapse, is termed the inertial cavitation threshold. The magnitude of the inertial cavitation threshold is typically limited by mechanisms other than homogeneous nucleation such that the theoretical maximum is never achieved. However, the onset of inertial cavitation can be suppressed by increasing the static pressure of the fluid. The inertial cavitation threshold was measured in ultrapure water at static pressures up to 30 MPa (300 bars) by exciting a radially symmetric standing wave field in a spherical resonator driven at a resonant frequency of 25.5 kHz. The threshold was found to increase linearly with the static pressure; an exponentially decaying temperature dependence was also found. The nature and properties of the nucleating mechanisms were investigated by comparing the measured thresholds to an independent analysis of the particulate content and available models for nucleation.

  10. Effect of friction on the performance of inertial slider

    Indian Academy of Sciences (India)

    K Anantheshwara; N S Murali; M S Bobji

    2008-06-01

    Inertial sliders are friction based drives used to position with a resolution of a few hundred of nanometers to over a range of few millimeters. The compactness and simple construction enabled it to be used as a coarse positioner in various Scanning Probe Microscopes (SPM). Even heavy masses has been thought off earlier to use the inertial slider to position precisely, lack of understanding in the dynamical friction behaviour has been the main reason why the inertial sliders potential has not been explored fully in any practical device. In this paper, we have studied the effect of different operating parameters on the step size of the slider. The inertial mass is kept on three sapphire balls, which are attached to shear piezoelectric material. The behaviour of inertial mass was studied for different input waveforms and different surface conditions that come in contact with the sapphire balls. It was observed that under lubricated conditions the step size was reduced.

  11. Precision Positioning and Inertial Guidance Sensors. Technology and Operational Aspects

    Science.gov (United States)

    1981-03-01

    the user equipment tesi locations in the southwestern United States. The Navstar satellites transmit a composite signal at two L-band frequencies. One...total program. VII. SUWO.RY OF TESI RESULTS By count, the predominant Class II t,.rminal configuration tested ias an an actively synchronized user...coin- cide with the missile body axes as shown in Figure 2 Figure I Missile Navigation Syztem Functional Block Diagram A functional block diagram of the

  12. Laser Inertial Fusion-based Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    OpenAIRE

    Kramer, Kevin James

    2010-01-01

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by ...

  13. Characterizing simulated galaxy stellar mass histories

    CERN Document Server

    Cohn, J D

    2014-01-01

    Galaxy formation simulations can now predict many galaxy properties and their evolution through time. To go beyond studying average stellar mass history properties, we classified ensembles of simulated stellar mass histories, holding fixed their z=0 stellar mass. We applied principal component analysis (PCA) to stellar mass histories from the dark matter plus semi-analytic Millennium simulation and the hydrodynamical OverWhelmingly Large Simulations (OWLS) project, finding that a large fraction of the total scatter around the average stellar mass history for each sample is due to only one PCA fluctuation. This fluctuation differs between some different models sharing the same z=0 stellar mass and between lower (<=3e10 M_o) and higher final stellar mass Millennium samples. We correlated the PCA characterization with several $z=0$ galaxy observables (in principle observable in a survey) and galaxy halo history properties. We also explored separating galaxy stellar mass histories into classes, using the large...

  14. The Supernova - A Stellar Spectacle.

    Science.gov (United States)

    Straka, W. C.

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. The following topics concerning supernovae are included: the outburst as observed and according to theory, the stellar remnant, the nebular remnant, and a summary…

  15. Mixing in massive stellar mergers

    NARCIS (Netherlands)

    Gaburov, E.; jr. Lombardi, J.C.; Portegies Zwart, S.

    2008-01-01

    The early evolution of dense star clusters is possibly dominated by close interactions between stars, and physical collisions between stars may occur quite frequently. Simulating a stellar collision event can be an intensive numerical task, as detailed calculations of this process require hydrodynam

  16. The Stellar Activity - Rotation Relationship

    CERN Document Server

    Wright, Nicholas J; Mamajek, Eric E; Henry, Gregory W

    2012-01-01

    Using a new catalog of 824 solar and late-type stars with X-ray luminosities and rotation periods we have studied the relationship between rotation and stellar activity. From an unbiased subset of this sample the power law slope of the unsaturated regime, $L_X/L_{bol}\\propto Ro^\\beta$, is fit as $\\beta=-2.70\\pm0.13$. This is inconsistent with the canonical $\\beta=-2$ slope to a confidence of 5$\\sigma$ and argues for an interface-type dynamo. Super-saturation is observed for the fastest rotators in our sample and its parametric dependencies are explored. Significant correlations are found with both the corotation radius and the excess polar updraft, the latter theory being supported by other observations. We also present a new X-ray population synthesis model of the mature stellar component of our Galaxy and use it to reproduce deep observations of a high Galactic latitude field. The model, XStar, can be used to test models of stellar spin-down and dynamo decay, as well as for estimating stellar X-ray contamin...

  17. Integrated Circuit Stellar Magnitude Simulator

    Science.gov (United States)

    Blackburn, James A.

    1978-01-01

    Describes an electronic circuit which can be used to demonstrate the stellar magnitude scale. Six rectangular light-emitting diodes with independently adjustable duty cycles represent stars of magnitudes 1 through 6. Experimentally verifies the logarithmic response of the eye. (Author/GA)

  18. Fundamental stellar properties from asteroseismology

    DEFF Research Database (Denmark)

    Silva Aguirre, V.; Casagrande, L.; Miglio, A.

    2013-01-01

    Accurate characterization of stellar populations is of prime importance to correctly understand the formation and evolution process of our Galaxy. The field of asteroseismology has been particularly successful in such an endeavor providing fundamental parameters for large samples of stars in diff...

  19. Mixing in massive stellar mergers

    NARCIS (Netherlands)

    Gaburov, E.; jr. Lombardi, J.C.; Portegies Zwart, S.

    2008-01-01

    The early evolution of dense star clusters is possibly dominated by close interactions between stars, and physical collisions between stars may occur quite frequently. Simulating a stellar collision event can be an intensive numerical task, as detailed calculations of this process require

  20. Numerical methods for stellarator optimization

    Energy Technology Data Exchange (ETDEWEB)

    Morris, R.N.; Hedrick, C.L.; Hirshman, S.P.; Lyon, J.F.; Rome, J.A.

    1989-01-01

    A numerical optimization procedure utilizing an inverse 3-D equilibrium solver, a Mercier stability assessment, a deeply-trapped-particle loss assessment, and a nonlinear optimization package has been used to produce low aspect ratio (A = 4) stellarator designs. These designs combine good stability and improved transport with a compact configuration. 7 refs., 2 figs., 1 tab.

  1. Inertial measurement unit-camera calibration based on incomplete inertial sensor information

    Institute of Scientific and Technical Information of China (English)

    Hong LIU; Yu-long ZHOU; Zhao-peng GU

    2014-01-01

    This paper is concerned with the problem of estimating the relative orientation between an inertial measurement unit (IMU) and a camera. Unlike most existing IMU-camera calibrations, the main challenge in this paper is that the information output from the IMU is incomplete. For example, only two tilt information can be read from the gravity sensor of a smart phone. Despite incomplete inertial information, there are strong restrictions between the IMU and camera coordinate systems. This paper addresses the incomplete information based IMU-camera calibration problem by exploiting the intrinsic restrictions among the coordinate transformations. First, the IMU transformation between two poses is formulated with the unknown IMU information. Then the defective IMU information is restored using the complementary visual information. Finally, the Levenberg-Marquardt (LM) algorithm is applied to estimate the optimal calibration result in noisy environments. Experiments on both synthetic and real data show the validity and robustness of our algorithm.

  2. Generalized Lawson Criteria for Inertial Confinement Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Tipton, Robert E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-08-27

    The Lawson Criterion was proposed by John D. Lawson in 1955 as a general measure of the conditions necessary for a magnetic fusion device to reach thermonuclear ignition. Over the years, similar ignition criteria have been proposed which would be suitable for Inertial Confinement Fusion (ICF) designs. This paper will compare and contrast several ICF ignition criteria based on Lawson’s original ideas. Both analytical and numerical results will be presented which will demonstrate that although the various criteria differ in some details, they are closely related and perform similarly as ignition criteria. A simple approximation will also be presented which allows the inference of each ignition parameter directly from the measured data taken on most shots fired at the National Ignition Facility (NIF) with a minimum reliance on computer simulations. Evidence will be presented which indicates that the experimentally inferred ignition parameters on the best NIF shots are very close to the ignition threshold.

  3. Membrane-less microfiltration using inertial microfluidics.

    Science.gov (United States)

    Warkiani, Majid Ebrahimi; Tay, Andy Kah Ping; Guan, Guofeng; Han, Jongyoon

    2015-07-08

    Microfiltration is a ubiquitous and often crucial part of many industrial processes, including biopharmaceutical manufacturing. Yet, all existing filtration systems suffer from the issue of membrane clogging, which fundamentally limits the efficiency and reliability of the filtration process. Herein, we report the development of a membrane-less microfiltration system by massively parallelizing inertial microfluidics to achieve a macroscopic volume processing rates (~ 500 mL/min). We demonstrated the systems engineered for CHO (10-20 μm) and yeast (3-5 μm) cells filtration, which are two main cell types used for large-scale bioreactors. Our proposed system can replace existing filtration membrane and provide passive (no external force fields), continuous filtration, thus eliminating the need for membrane replacement. This platform has the desirable combinations of high throughput, low-cost, and scalability, making it compatible for a myriad of microfiltration applications and industrial purposes.

  4. Inertial-particle dispersion and diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Afonso, Marco Martins [Universite de Toulouse, INP/UPS/CNRS, Institut de Mecanique des Fluides de Toulouse - groupe Particules Spray et Combustion, allee du Professeur Camille Soula, 31400 Toulouse (France); Mazzino, Andrea [Department of Physics - University of Genova, and CNISM and INFN - Genova Section, via Dodecaneso 33, 16146 Genova (Italy); Muratore-Ginanneschi, Paolo, E-mail: marcomar@fisica.unige.it [Department of Mathematics and Statistics - University of Helsinki, PO Box 4, 00014 Helsinki (Finland)

    2011-12-22

    We analytically investigate the dynamics of inertial particles in incompressible flows in the limit of small but finite inertia, focusing on two specific instances. First, we study the concentration of particles continuously emitted from a point source with a given exit velocity distribution. The anisotropy of the latter turns out to be a necessary factor for the presence of a correction (with respect to the corresponding tracer case) at order square root of the Stokes number. Secondly, by means of a multiple-scale expansion, we analyse the particle effective diffusivity, and in particular its dependence on Brownian diffusivity, gravity effects and particle-to-fluid density ratio. In both cases, we obtain forced advection-diffusion equations for auxiliary quantities in the physical space, thus simplifying the problem from the full phase space to a system which can easily be solved numerically.

  5. Inertial capture in flow through porous media

    Science.gov (United States)

    Andrade, J. S., Jr.; Araújo, A. D.; Vasconcelos, T. F.; Herrmann, H. J.

    2008-08-01

    We investigate through numerical calculation of non-Brownian particles transported by a fluid in a porous medium, the influence of geometry and inertial effects on the capture efficiency of the solid matrix. In the case of a periodic array of cylinders and under the action of gravity, our results reveal that δ ˜ St, where δ is the particle capture efficiency, and St is the Stokes number. In the absence of gravity, we observe a typical second order transition between non-trapping and trapping of particles that can be expressed as δ ˜ ( St - St c ) α , with an exponent α ≈ 0.5, where St c is the critical Stokes number. We also perform simulations for flow through a random porous structure and confirm that its capture behavior is consistent with the simple periodic model.

  6. Eddy diffusivities of inertial particles under gravity

    CERN Document Server

    Afonso, Marco Martins; Muratore-Ginanneschi, Paolo

    2011-01-01

    The large-scale/long-time transport of inertial particles of arbitrary mass density under gravity is investigated by means of a formal multiple-scale perturbative expansion in the scale-separation parametre between the carrier flow and the particle concentration field. The resulting large-scale equation for the particle concentration is determined, and is found to be diffusive with a positive-definite eddy diffusivity. The calculation of the latter tensor is reduced to the resolution of an auxiliary differential problem, consisting of a coupled set of two differential equations in a (6+1)-dimensional coordinate system (3 space coordinates plus 3 velocity coordinates plus time). Although expensive, numerical methods can be exploited to obtain the eddy diffusivity, for any desirable non-perturbative limit (e.g. arbitrary Stokes and Froude numbers). The aforementioned large-scale equation is then specialized to deal with two different relevant perturbative limits: i) vanishing of both Stokes time and sedimenting...

  7. Inertial particles in homogeneous shear turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Nicolai, Claudia; Jacob, Boris [CNR-INSEAN, via di Vallerano 139, 00128 Rome (Italy); Gualtieri, Paolo; Piva, Renzo, E-mail: claudia.nicolai@uniroma1.it [DMA, Sapienza Universita di Roma, Via Eudossiana 18, 00184 Rome (Italy)

    2011-12-22

    The characteristics of inertial particles distribution in a uniformly sheared turbulent flow are investigated, with the aim of quantifying the effects associated with the large-scale anisotropy induced by the mean velocity gradient. The focus of the analysis is on clustering aspects, and in particular on the dependence of the radial distribution function on both the directionality and the magnitude of the observation scale. We discuss experimental data measured in a homogeneous shear flow seeded with particles of size comparable with the Kolmogorov length scale and Stokes number St Almost-Equal-To 0.3, and discuss their distribution properties in comparison with results provided by related one-way coupled direct numerical simulations which make use of the point-force approximation.

  8. High-Gain Magnetized Inertial Fusion

    Science.gov (United States)

    Slutz, Stephen A.; Vesey, Roger A.

    2012-01-01

    Magnetized inertial fusion (MIF) could substantially ease the difficulty of reaching plasma conditions required for significant fusion yields, but it has been widely accepted that the gain is not sufficient for fusion energy. Numerical simulations are presented showing that high-gain MIF is possible in cylindrical liner implosions based on the MagLIF concept [S. A. Slutz et al Phys. Plasmas 17, 056303 (2010)PHPAEN1070-664X10.1063/1.3333505] with the addition of a cryogenic layer of deuterium-tritium (DT). These simulations show that a burn wave propagates radially from the magnetized hot spot into the surrounding much denser cold DT given sufficient hot-spot areal density. For a drive current of 60 MA the simulated gain exceeds 100, which is more than adequate for fusion energy applications. The simulated gain exceeds 1000 for a drive current of 70 MA.

  9. Tripartite Entanglements in Non-inertial Frames

    CERN Document Server

    Shamirzai, Mahmoud; Soltani, Morteza

    2011-01-01

    Entanglement degradation caused by the Unruh effect is discussed for the tripartite GHZ or W states constructed by modes of a non-interacting quantum field viewed by one inertial observer and two uniformly accelerated observers. For fermionic states, the Unruh effect even for infinite accelerations cannot completely remove the entanglement. However, for the bosonic states, the situation is different and the entanglement vanishes asymptotically. Also, the entanglement is studied for the bipartite subsystems. While for the GHZ states all the bipartite subsystems are identically disentangled, for the W states the bipartite subsystems are somewhat entangled, though, this entanglement can be removed for appropriately accelerated observers. Interestingly, logarithmic negativity as a measure for determining the entanglement of one part of the system relative to the other two parts, is not generally the same for different parts. This means that we encounter tripartite systems where each part is differently entangled ...

  10. Inertial Fusion Energy at Denim (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Velarde, G.

    2005-07-01

    The paper describes the history and the research carried out in the field on Inertial Confinement Fusion (ICF) since 1966 at the Spanish Atomic Energy Commission (JEN) up to present time at the Institute of Nuclear Fusion (DENIM) of the Polytechnic University of Madrid (UPM), Late in the 70s, we developed the NORCLA code that was the first non-classified coupled code to analyze the different processes held in ICF. Since then, we have developed a set of more accurate codes such as the ARWEN (two-dimensional transport), JIMENA and ANALOP (Atomic physics), ACAB (safety and environmental), material and reactor chambers and advanced fuels. The paper tells also the origins of DENIM and all the efforts made to achieve an international declassification in ICF research. (Author)

  11. Targeted Optimization of Quasi-Symmetric Stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Hegna, Chris C. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics; Anderson, D. T. [Univ. of Wisconsin, Madison, WI (United States); Talmadge, J. N. [Univ. of Wisconsin, Madison, WI (United States)

    2016-10-06

    The proposed research focuses on targeted areas of plasma physics dedicated to improving the stellarator concept. Research was pursued in the technical areas of edge/divertor physics in 3D configurations, magnetic island physics in stellarators, the role of 3D shaping on microinstabilities and turbulent transport and energetic ion confinement in stellarators.

  12. Towards the Intensity Interferometry Stellar Imaging System

    CERN Document Server

    Daniel, M; Dravins, D; Kieda, D; Le Bohec, S; Núñez, P; Ribak, E

    2009-01-01

    The imminent availability of large arrays of large light collectors deployed to exploit atmospheric Cherenkov radiation for gamma-ray astronomy at more than 100GeV, motivates the growing interest in application of intensity interferometry in astronomy. Indeed, planned arrays numbering up to one hundred telescopes will offer close to 5,000 baselines, ranging from less than 50m to more than 1000m. Recent and continuing signal processing technology developments reinforce this interest. Revisiting Stellar Intensity Interferometry for imaging is well motivated scientifically. It will fill the short wavelength (B/V bands) and high angular resolution (< 0.1mas) gap left open by amplitude interferometers. It would also constitute a first and important step toward exploiting quantum optics for astronomical observations, thus leading the way for future observatories. In this paper we outline science cases, technical approaches and schedule for an intensity interferometer to be constructed and operated in the visible...

  13. BOOK REVIEW: Advanced Diagnostics for Magnetic and Inertial Confinement Fusion

    Science.gov (United States)

    Stott, PE; Wootton, A.; Gorini, G.; Sindoni, E.; Batani, D.

    2003-02-01

    This book is a collection of papers, written by specialists in the field, on advanced topics of nuclear fusion diagnostics. The 78 contributions were originally presented at the International Conference on Advanced Diagnostics for Magnetic and Inertial Fusion held at Villa Monastero, Italy in September 2001. Both magnetically confined and inertial fusion programmes are quite extensively covered, with more emphasis given to the former scheme. In the case of magnetic confinement, since the present international programme is strongly focused on next-step devices, particular attention is devoted to techniques and technologies viable in an environment with strong neutron fluxes. Indeed, in the first section, the various methods are considered in the perspective of performing the measurements of the relevant parameters in conditions approaching a burning plasma, mainly in the Tokamak configuration. The most demanding requirements, like the implications of the use of tritium and radiation resistance, are reviewed and the most challenging open issues, which require further research and development, are also clearly mentioned. The following three sections are devoted to some of the most recent developments in plasma diagnostics, which are grouped according to the following classification: `Neutron and particle diagnostics', `Optical and x-ray diagnostics' and `Interferometry, Polarimetry and Thomson Scattering'. In these chapters, several of the most recent results are given, covering measurements taken on the most advanced experiments around the world. Here the developments described deal more with the requirements imposed by the physical issues to be studied. They are therefore more focused on the approaches adopted to increase the spatial and time resolution of the diagnostics, on some methods to improve the characterisation of the turbulence and on fast particles. Good coverage is given to neutron diagnostics, which are assuming increasing relevance as the plasma

  14. Theory of stellar convection - II. First stellar models

    Science.gov (United States)

    Pasetto, S.; Chiosi, C.; Chiosi, E.; Cropper, M.; Weiss, A.

    2016-07-01

    We present here the first stellar models on the Hertzsprung-Russell diagram, in which convection is treated according to the new scale-free convection theory (SFC theory) by Pasetto et al. The aim is to compare the results of the new theory with those from the classical, calibrated mixing-length (ML) theory to examine differences and similarities. We integrate the equations describing the structure of the atmosphere from the stellar surface down to a few per cent of the stellar mass using both ML theory and SFC theory. The key temperature over pressure gradients, the energy fluxes, and the extension of the convective zones are compared in both theories. The analysis is first made for the Sun and then extended to other stars of different mass and evolutionary stage. The results are adequate: the SFC theory yields convective zones, temperature gradients ∇ and ∇e, and energy fluxes that are very similar to those derived from the `calibrated' MT theory for main-sequence stars. We conclude that the old scale dependent ML theory can now be replaced with a self-consistent scale-free theory able to predict correct results, as it is more physically grounded than the ML theory. Fundamentally, the SFC theory offers a deeper insight of the underlying physics than numerical simulations.

  15. Theory of stellar convection II: first stellar models

    CERN Document Server

    Pasetto, S; Chiosi, E; Cropper, M; Weiss, A

    2015-01-01

    We present here the first stellar models on the Hertzsprung-Russell diagram (HRD), in which convection is treated according to the novel scale-free convection theory (SFC theory) by Pasetto et al. (2014). The aim is to compare the results of the new theory with those from the classical, calibrated mixing-length (ML) theory to examine differences and similarities. We integrate the equations describing the structure of the atmosphere from the stellar surface down to a few percent of the stellar mass using both ML theory and SFC theory. The key temperature over pressure gradients, the energy fluxes, and the extension of the convective zones are compared in both theories. The analysis is first made for the Sun and then extended to other stars of different mass and evolutionary stage. The results are adequate: the SFC theory yields convective zones, temperature gradients of the ambient and of the convective element, and energy fluxes that are very similar to those derived from the "calibrated" MT theory for main s...

  16. Crank inertial load affects freely chosen pedal rate during cycling.

    Science.gov (United States)

    Hansen, Ernst Albin; Jørgensen, Lars Vincents; Jensen, Kurt; Fregly, Benjamin Jon; Sjøgaard, Gisela

    2002-02-01

    Cyclists seek to maximize performance during competition, and gross efficiency is an important factor affecting performance. Gross efficiency is itself affected by pedal rate. Thus, it is important to understand factors that affect freely chosen pedal rate. Crank inertial load varies greatly during road cycling based on the selected gear ratio. Nevertheless, the possible influence of crank inertial load on freely chosen pedal rate and gross efficiency has never been investigated. This study tested the hypotheses that during cycling with sub-maximal work rates, a considerable increase in crank inertial load would cause (1) freely chosen pedal rate to increase, and as a consequence, (2) gross efficiency to decrease. Furthermore, that it would cause (3) peak crank torque to increase if a constant pedal rate was maintained. Subjects cycled on a treadmill at 150 and 250W, with low and high crank inertial load, and with preset and freely chosen pedal rate. Freely chosen pedal rate was higher at high compared with low crank inertial load. Notably, the change in crank inertial load affected the freely chosen pedal rate as much as did the 100W increase in work rate. Along with freely chosen pedal rate being higher, gross efficiency at 250W was lower during cycling with high compared with low crank inertial load. Peak crank torque was higher during cycling at 90rpm with high compared with low crank inertial load. Possibly, the subjects increased the pedal rate to compensate for the higher peak crank torque accompanying cycling with high compared with low crank inertial load.

  17. Stellar Work of Art

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Poster Version This painterly portrait of a star-forming cloud, called NGC 346, is a combination of multiwavelength light from NASA's Spitzer Space Telescope (infrared), the European Southern Observatory's New Technology Telescope (visible), and the European Space Agency's XMM-Newton space telescope (X-ray). The infrared observations highlight cold dust in red, visible data show glowing gas in green, and X-rays show very warm gas in blue. Ordinary stars appear as blue spots with white centers, while young stars enshrouded in dust appear as red spots with white centers. The colorful picture demonstrates that stars in this region are being created by two different types of triggered star formation one involving wind, and the other, radiation. Triggered star formation occurs when massive stars spur new, smaller stars into existence. The first radiation-based mechanism is demonstrated near the center of the cloud. There, radiation from the massive stars is eating away at the surrounding dust cloud, creating shock waves that compress gas and dust into new stars. This compressed material appears as an arc-shaped orange-red filament, while the new stars within this filament are still blanketed with dust and cannot be seen. The second wind-based mechanism is at play higher up in the cloud. The isolated, pinkish blob of stars at the upper left was triggered by winds from a massive star located to the left of it. This massive star blew up in a supernova explosion 50,000 years ago, but before it died, its winds pushed gas and dust together into new stars. While this massive star cannot be seen in the image, a bubble created when it exploded can be seen near the large, white spot with a blue halo at the upper left (this white spot is actually a collection of three stars). NGC 346 is the brightest star-forming region in the Small Magellanic Cloud, an irregular dwarf galaxy that orbits our Milky Way galaxy, 210,000 light-years away.

  18. Cryogenic hydrogen fuel for controlled inertial confinement fusion (formation of reactor-scale cryogenic targets)

    Science.gov (United States)

    Aleksandrova, I. V.; Koresheva, E. R.; Krokhin, O. N.; Osipov, I. E.

    2016-12-01

    In inertial fusion energy research, considerable attention has recently been focused on low-cost fabrication of a large number of targets by developing a specialized layering module of repeatable operation. The targets must be free-standing, or unmounted. Therefore, the development of a target factory for inertial confinement fusion (ICF) is based on methods that can ensure a cost-effective target production with high repeatability. Minimization of the amount of tritium (i.e., minimization of time and space at all production stages) is a necessary condition as well. Additionally, the cryogenic hydrogen fuel inside the targets must have a structure (ultrafine layers—the grain size should be scaled back to the nanometer range) that supports the fuel layer survivability under target injection and transport through the reactor chamber. To meet the above requirements, significant progress has been made at the Lebedev Physical Institute (LPI) in the technology developed on the basis of rapid fuel layering inside moving free-standing targets (FST), also referred to as the FST layering method. Owing to the research carried out at LPI, unique experience has been gained in the development of the FST-layering module for target fabrication with an ultrafine fuel layer, including a reactor- scale target design. This experience can be used for the development of the next-generation FST-layering module for construction of a prototype of a target factory for power laser facilities and inertial fusion power plants.

  19. Simulation on a novel micron-array inertial impactor for submicron and ultrafine particle separation

    Science.gov (United States)

    Liu, Rui-Tao; Tao, Lu-Qi; Yang, Yi; Ren, Tian-Ling

    2016-08-01

    The particulate matter (PM), which was put forward in 1997 by US, had taken more and more attention due to the influence on human health. Although the mass concentration, number concentration and chemical composition of PM were still major research directions, how to collect these PMs more efficiently becomes critical. Inertial impactor is an effective separation device, however, due to different motion states of PM2.5 and PM0.3 in the flow field, the inertial impactor which can separate PM0.3 from other PMs has not been fabricated. In this work, the motion states for both submicron and ultrafine particles were studied by using classical theory of channel aerodynamic, and a novel micron-array inertial impactor was designed and simulated for the first time. Besides, the influence of some characteristic parameters (W, T, S, Dc, etc.) on particle collection efficiency were researched and discussed through simulation results. This novel structure can be easily fabricated by MEMS technology or laser direct writing and also can be widely used in particle separation or flexible sensor fields.

  20. Cryogenic hydrogen fuel for controlled inertial confinement fusion (formation of reactor-scale cryogenic targets)

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrova, I. V.; Koresheva, E. R., E-mail: elena.koresheva@gmail.com; Krokhin, O. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Osipov, I. E. [Power Efficiency Centre, Inter RAO UES (Russian Federation)

    2016-12-15

    In inertial fusion energy research, considerable attention has recently been focused on low-cost fabrication of a large number of targets by developing a specialized layering module of repeatable operation. The targets must be free-standing, or unmounted. Therefore, the development of a target factory for inertial confinement fusion (ICF) is based on methods that can ensure a cost-effective target production with high repeatability. Minimization of the amount of tritium (i.e., minimization of time and space at all production stages) is a necessary condition as well. Additionally, the cryogenic hydrogen fuel inside the targets must have a structure (ultrafine layers—the grain size should be scaled back to the nanometer range) that supports the fuel layer survivability under target injection and transport through the reactor chamber. To meet the above requirements, significant progress has been made at the Lebedev Physical Institute (LPI) in the technology developed on the basis of rapid fuel layering inside moving free-standing targets (FST), also referred to as the FST layering method. Owing to the research carried out at LPI, unique experience has been gained in the development of the FST-layering module for target fabrication with an ultrafine fuel layer, including a reactor- scale target design. This experience can be used for the development of the next-generation FST-layering module for construction of a prototype of a target factory for power laser facilities and inertial fusion power plants.

  1. A Pedestrian Dead Reckoning System Integrating Low-Cost MEMS Inertial Sensors and GPS Receiver

    Directory of Open Access Journals (Sweden)

    Jin-feng Li

    2014-04-01

    Full Text Available The body-mounted inertial systems for pedestrian navigation do not require any preinstalled facilities and can run autonomously. The advantages over other technologies make it especially attractive for the applications such as first responders, military and consumer markets. The hardware platform integrating the low-cost, low-power and small-size MEMS (micro-electro-mechanical systems inertial sensors and GPS (global positioning system receiver is proposed. When the satellite signals are available, the location of the pedestrian is directly obtained from the GPS receiver. The inertial sensors are the complement of the GPS receiver in places where the GPS signals are not available, such as indoors, urban canyons and places under dense foliages. The height tracking is achieved by the barometer. The proposed PDR (pedestrian dead reckoning algorithm is real-timely implemented in the platform. The simple but effective step detection and step length estimation method are realized to reduce the computation and memory requirements on the microprocessor. A complementary filter is proposed to fuse the data from the accelerometer, gyroscope and digital compass for decreasing the heading error, which is the main error source in positioning. The reliability and accuracy of the proposed system is verified by field pedestrian walking tests in outdoors and indoors. The positioning error is less than 4% of the total traveled distance. The results indicate that the pedestrian dead reckoning system is able to provide satisfactory tracking performance.

  2. A Toolbox of Aiding Techniques for the HUGIN AUV Integrated Inertial Navigation System

    Directory of Open Access Journals (Sweden)

    Bjørn Jalving

    2004-07-01

    Full Text Available Modern AUV designs must handle submerged autonomous operation for long periods of time. The state of the art solution embedded in the HUGIN AUVs is a Doppler Velocity Log (DVL aided Inertial Navigation System (INS that can integrate various forms of position measurement updates. In autonomous operations, position updates are only available in limited periods of time or space, thus the core velocity aided inertial navigation system must exhibit high accuracy However, position uncertainty of a DVL aided inertial navigation system will eventually drift off, compromising either mission operation or requirements for accurate positioning of payload data. To meet the requirements for a range of military and civilian AUV applications, the HUGIN vehicles come with a flexible and powerful set of navigation techniques. Methods for position updates include GPS surface fix, DGPS-USBL, Underwater Transponder Positioning (UTP and bathymetric terrain navigation. Based on synthetic aperture sonar technology, a potentially revolutionary accurate velocity measurement is under development. HUGIN also comes with a navigation post-processing system (NavLab, which can be applied to increase navigational integrity and maximize position accuracy.

  3. Review on Recent Developments in Laser Driven Inertial Fusion

    Directory of Open Access Journals (Sweden)

    M. Ghoranneviss

    2014-01-01

    Full Text Available Discovery of the laser in 1960 hopes were based on using its very high energy concentration within very short pulses of time and very small volumes for energy generation from nuclear fusion as “Inertial Fusion Energy” (IFE, parallel to the efforts to produce energy from “Magnetic Confinement Fusion” (MCF, by burning deuterium-tritium (DT in high temperature plasmas to helium. Over the years the fusion gain was increased by a number of magnitudes and has reached nearly break-even after numerous difficulties in physics and technology had been solved. After briefly summarizing laser driven IFE, we report how the recently developed lasers with pulses of petawatt power and picosecond duration may open new alternatives for IFE with the goal to possibly ignite solid or low compressed DT fuel thereby creating a simplified reactor scheme. Ultrahigh acceleration of plasma blocks after irradiation of picosecond (PS laser pulses of around terawatt (TW power in the range of 1020 cm/s2 was discovered by Sauerbrey (1996 as measured by Doppler effect where the laser intensity was up to about 1018 W/cm2. This is several orders of magnitude higher than acceleration by irradiation based on thermal interaction of lasers has produced.

  4. Advanced Scintillator Detectors for Neutron Imaging in Inertial Confinement Fusion

    Science.gov (United States)

    Geppert-Kleinrath, Verena; Danly, Christopher; Merrill, Frank; Simpson, Raspberry; Volegov, Petr; Wilde, Carl

    2016-10-01

    The neutron imaging team at Los Alamos National Laboratory (LANL) has been providing two-dimensional neutron imaging of the inertial confinement fusion process at the National Ignition Facility (NIF) for over five years. Neutron imaging is a powerful tool in which position-sensitive detectors register neutrons emitted in the fusion reactions, producing a picture of the burning fuel. Recent images have revealed possible multi-dimensional asymmetries, calling for additional views to facilitate three-dimensional imaging. These will be along shorter lines of sight to stay within the existing facility at NIF. In order to field imaging capabilities equivalent to the existing system several technological challenges have to be met: high spatial resolution, high light output, and fast scintillator response to capture lower-energy neutrons, which have scattered from non-burning regions of fuel. Deuterated scintillators are a promising candidate to achieve the timing and resolution required; a systematic study of deuterated and non-deuterated polystyrene and liquid samples is currently ongoing. A test stand has been implemented to measure the response function, and preliminary data on resolution and light output have been obtained at the LANL Weapons Neutrons Research facility.

  5. Energy harvesting potential of tuned inertial mass electromagnetic transducers

    Science.gov (United States)

    Asai, Takehiko; Araki, Yoshikazu; Ikago, Kohju

    2017-02-01

    The demand for developing renewable energy technologies has been growing in today's society. As one of promising renewable energy sources, large-scale energy harvesting from structural vibrations employing electromagnetic transducers has recently been proposed and considerable effort has been devoted to increase the power generation capability. In this paper, we introduce the mechanism of a tuned inertial mass electromagnetic transducer (TIMET), which can absorb vibratory energy more efficiently by tuning the parameters to adjust the system. Then we propose a new vibratory energy harvester with the TIMET and determine the parameter values for the device with a simple static admittance (SA) control law to maximize the energy harvested from a stationary stochastic disturbance. To investigate the energy harvesting potential of the TIMET further, the performance-guaranteed (PG) control and the LQG control proposed in the literature are applied as well. Then the numerical simulation studies are carried out and the effectiveness of the proposed energy harvester is examined by comparing the traditional electromagnetic transducers.

  6. Stellar populations of ultraluminous infrared galaxies

    CERN Document Server

    Hou, L G; Kong, M Z; Xue-Bing, Wu

    2011-01-01

    Ultraluminous infrared galaxies (ULIRGs) have several types according to dominance of starburst or AGN component. We made stellar population analysis for a sample of 160 ULIRGs to study the evolution of ULIRGs. We found that the dominance of intermediate-age and old stellar populations increases along the sequence of HII-like ULIRGs, Seyfert-HII composite ULIRGs, and Seyfert 2 ULIRGs. Consequently the typical mean stellar age and the stellar mass increase along the sequence. Comparing the gas mass estimated from the CO measurements with the stellar mass estimated from the optical spectra, we found that gas fraction is anti-correlated with the stellar mass. HII-like ULIRGs with small stellar masses do not possess enough gas and the total mass, and therefore have no evolution connections with massive Seyfert 2 ULIRGs. Only massive ULIRGs may follow the evolution sequence toward AGNs, and massive HII-like ULIRGs are probably in an earlier stage of the sequence.

  7. Magnetohydrostatic modelling of stellar coronae

    CERN Document Server

    MacTaggart, David; Neukirch, Thomas; Donati, Jean-Francois

    2015-01-01

    We introduce to the stellar physics community a method of modelling stellar coronae that can be considered to be an extension of the potential field. In this approach, the magnetic field is coupled to the background atmosphere. The model is magnetohydrostatic (MHS) and is a balance between the Lorentz force, the pressure gradient and gravity. Analytical solutions are possible and we consider a particular class of equilibria in this paper. The model contains two free parameters and the effects of these on both the geometry and topology of the coronal magnetic field are investigated. A demonstration of the approach is given using a magnetogram derived from Zeeman-Doppler imaging of the 0.75 M$_{\\odot}$ M-dwarf star GJ 182.

  8. From stellar nebula to planetesimals

    CERN Document Server

    Marboeuf, Ulysse; Alibert, Yann; Cabral, Nahuel; Benz, Willy

    2014-01-01

    Solar and extrasolar comets and extrasolar planets are the subject of numerous studies in order to determine their chemical composition and internal structure. In the case of planetesimals, their compositions are important as they govern in part the composition of future planets. The present works aims at determining the chemical composition of icy planetesimals, believed to be similar to present day comets, formed in stellar systems of solar chemical composition. The main objective of this work is to provide valuable theoretical data on chemical composition for models of planetesimals and comets, and models of planet formation and evolution. We have developed a model that calculates the composition of ices formed during the cooling of the stellar nebula. Coupled with a model of refractory element formation, it allows us to determine the chemical composition and mass ratio of ices to rocks in icy planetesimals throughout in the protoplanetary disc. We provide relationships for ice line positions (for differen...

  9. Mixing in massive stellar mergers

    CERN Document Server

    Gaburov, E; Zwart, S Portegies

    2007-01-01

    The early evolution of dense star clusters is possibly dominated by close interactions between stars, and physical collisions between stars may occur quite frequently. Simulating a stellar collision event can be an intensive numerical task, as detailed calculations of this process require hydrodynamic simulations in three dimensions. We present a computationally inexpensive method in which we approximate the merger process, including shock heating, hydrodynamic mixing and mass loss, with a simple algorithm which is based on conservation laws and a basic qualitative understanding of the hydrodynamics of stellar mergers. The algorithm is based on Archimedes' principle, which dictates the distribution of the fluid in stable equilibrium situation. We calibrate and apply the method to mergers of massive stars, as these are expected to occur in young and dense star clusters. We find that mergers between spectral type B stars ($\\sim$10\\msun) result in substantial mixing, whereas mergers between stars of different sp...

  10. Investigating Exoplanets Within Stellar Clusters

    Science.gov (United States)

    Glaser, Joseph Paul; Reisinger, Tyler; Thornton, Jonathan; McMillan, Stephen L. W.

    2017-01-01

    Recent surveys exploring nearby open clusters have yielded noticeable differences in the planetary population from that seen in the Field. This is surprising, as it is widely accepted that a majority of stars form within clustered environments before dispersing throughout the galaxy. Though dynamical arguments have been used to explain this discrepancy in the past, previous surveys' observational statistics and detection biases can also be used to argue that the open cluster planet population is indistinguishable from the Field.Our group aims to explore the role of stellar close encounters and interplanetary interactions in producing the observed exoplanet populations for both open cluster stars and Field stars. We employ a variety of different computational techniques to investigate these effects, ranging from traditional Monte Carlo scattering experiments to multi-scale n-body simulations. We are interested in: the effects of stellar binaries; Hot Jupiter migrations; long-period ice giants; and the habitability history of terrestrial planets.

  11. Stellar models in Brane Worlds

    CERN Document Server

    Linares, Francisco X; Ureña-Lopez, L Arturo

    2015-01-01

    We consider here a full study of stellar dynamics from the brane-world point of view in the case of constant density and of a polytropic fluid. We start our study cataloguing the minimal requirements to obtain a compact object with a Schwarszchild exterior, highlighting the low and high energy limit, the boundary conditions, and the appropriate behavior of Weyl contributions inside and outside of the star. Under the previous requirements we show an extensive study of stellar behavior, starting with stars of constant density and its extended cases with the presence of nonlocal contributions. Finally, we focus our attention to more realistic stars with a polytropic equation of state, specially in the case of white dwarfs, and study their static configurations numerically. One of the main results is that the inclusion of the Weyl functions from braneworld models allow the existence of more compact configurations than within General Relativity.

  12. Characterizing stellar and exoplanetary environments

    CERN Document Server

    Khodachenko, Maxim

    2015-01-01

    In this book an international group of specialists discusses studies of exoplanets subjected to extreme stellar radiation and plasma conditions. It is shown that such studies will help us to understand how terrestrial planets and their atmospheres, including the early Venus, Earth and Mars, evolved during the host star’s active early phase. The book presents an analysis of findings from Hubble Space Telescope observations of transiting exoplanets, as well as applications of advanced numerical models for characterizing the upper atmosphere structure and stellar environments of exoplanets. The authors also address detections of atoms and molecules in the atmosphere of “hot Jupiters” by NASA’s Spitzer telescope. The observational and theoretical investigations and discoveries presented are both timely and important in the context of the next generation of space telescopes. 
 The book is divided into four main parts, grouping chapters on exoplanet host star radiation and plasma environments, exoplanet u...

  13. The role of the NIF in the development of inertial fusion energy

    Energy Technology Data Exchange (ETDEWEB)

    Logan, B.G.

    1995-03-16

    Recent decisions by DOE to proceed with the National Ignition Facility (NIF) and the first half of the Induction Systems Linac Experiments (ILSE) can provide the scientific basis for inertial fusion ignition and high-repetition heavy-ion driver physics, respectively. Both are critical to Inertial Fusion Energy (IFE). A conceptual design has been completed for a 1.8-MJ, 500-TW, 0.35-{micro}m-solid-state laser system, the NIF. The NIF will demonstrate inertial fusion ignition and gain for national security applications, and for IFE development. It will support science applications using high-power lasers. The demonstration of inertial fusion ignition and gain, along with the parallel demonstration of the feasibility of an efficient, high-repetition-rate driver, would provide the basis for a follow-on Engineering Test Facility (ETF) identified in the National Energy Policy Act of 1992. The ETF would provide an integrated testbed for the development and demonstration of the technologies needed for IFE power plants. In addition to target physics of ignition, the NIF will contribute important data on IFE target chamber issues, including neutron damage, activation, target debris clearing, operational experience in many areas prototypical to future IFE power plants, and an opportunity to provide tests of candidate low-cost IFE targets and injection systems. An overview of the NIF design and the target area environments relevant to conducting IFE experiments are described in Section 2. In providing this basic data for IFE, the NIF will provide confidence that an ETF can be successful in the integration of drivers, target chambers, and targets for IFE.

  14. Inertial rotation measurement with atomic spins: From angular momentum conservation to quantum phase theory

    Science.gov (United States)

    Zhang, C.; Yuan, H.; Tang, Z.; Quan, W.; Fang, J. C.

    2016-12-01

    Rotation measurement in an inertial frame is an important technology for modern advanced navigation systems and fundamental physics research. Inertial rotation measurement with atomic spin has demonstrated potential in both high-precision applications and small-volume low-cost devices. After rapid development in the last few decades, atomic spin gyroscopes are considered a promising competitor to current conventional gyroscopes—from rate-grade to strategic-grade applications. Although it has been more than a century since the discovery of the relationship between atomic spin and mechanical rotation by Einstein [Naturwissenschaften, 3(19) (1915)], research on the coupling between spin and rotation is still a focus point. The semi-classical Larmor precession model is usually adopted to describe atomic spin gyroscope measurement principles. More recently, the geometric phase theory has provided a different view of the rotation measurement mechanism via atomic spin. The theory has been used to describe a gyroscope based on the nuclear spin ensembles in diamond. A comprehensive understanding of inertial rotation measurement principles based on atomic spin would be helpful for future applications. This work reviews different atomic spin gyroscopes and their rotation measurement principles with a historical overlook. In addition, the spin-rotation coupling mechanism in the context of the quantum phase theory is presented. The geometric phase is assumed to be the origin of the measurable rotation signal from atomic spins. In conclusion, with a complete understanding of inertial rotation measurements using atomic spin and advances in techniques, wide application of high-performance atomic spin gyroscopes is expected in the near future.

  15. Gravitational waves from stellar encounters

    CERN Document Server

    Capozziello, Salvatore

    2008-01-01

    The emission of gravitational waves from a system of massive objects interacting on elliptical, hyperbolic and parabolic orbits is studied in the quadrupole approximation. Analytical expressions are then derived for the gravitational wave luminosity, the total energy output and gravitational radiation amplitude. A crude estimate of the expected number of events towards peculiar targets (i.e. globular clusters) is also given. In particular, the rate of events per year is obtained for the dense stellar cluster at the Galactic Center.

  16. Fusion Based on Visible Light Positioning and Inertial Navigation Using Extended Kalman Filters.

    Science.gov (United States)

    Li, Zhitian; Feng, Lihui; Yang, Aiying

    2017-05-11

    With the rapid development of smart technology, the need for location-based services (LBS) increases every day. Since classical positioning technology such as GPS cannot satisfy the needs of indoor positioning, new indoor positioning technologies, such as Bluetooth, Wi-Fi, and Visible light communication (VLC), have already cut a figure. VLC positioning has been proposed because it has higher accuracy, costs less, and is easier to accomplish in comparison to the other indoor positioning technologies. However, the practicality of VLC positioning is limited since it is easily affected by multipath effects and the layout of LEDs. Thus, we propose a fusion positioning system based on extended Kalman filters, which can fuse the VLC position and the inertial navigation data. The accuracy of the fusion positioning system is in centimeters, which is better compared to the VLC-based positioning or inertial navigation alone. Furthermore, the fusion positioning system has high accuracy, saves energy, costs little, and is easy to install, making it a promising candidate for future indoor positioning applications.

  17. Inertial confinement fusion. 1995 ICF annual report, October 1994--September 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    Lawrence Livermore National Laboratory`s (LLNL`s) Inertial Confinement Fusion (ICF) Program is a Department of Energy (DOE) Defense Program research and advanced technology development program focused on the goal of demonstrating thermonuclear fusion ignition and energy gain in the laboratory. During FY 1995, the ICF Program continued to conduct ignition target physics optimization studies and weapons physics experiments in support of the Defense Program`s stockpile stewardship goals. It also continued to develop technologies in support of the performance, cost, and schedule goals of the National Ignition Facility (NIF) Project. The NIF is a key element of the DOE`s Stockpile Stewardship and Management Program. In addition to its primary Defense Program goals, the ICF Program provides research and development opportunities in fundamental high-energy-density physics and supports the necessary research base for the possible long-term application to inertial fusion energy (IFE). Also, ICF technologies have had spin-off applications for industrial and governmental use. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  18. Imaging of Stellar Surfaces with the Navy Precision Optical Interferometer

    Science.gov (United States)

    2015-09-18

    geostationary satellites : Signal-to- noise considerations,” in Proc. Advanced Maui Optical and Space Surveillance Technologies Conference, 2011. 6. D...possible, where the fringes are stabilized on very long baselines far below the fringe-tracking signal-to- noise ratio level and thus obtain high... phase observations on long baselines at shorter wavelengths in order to further increase the resolution. In this paper we describe the NPOI Stellar

  19. Stellar Populations of Shell Galaxies

    CERN Document Server

    Carlsten, S; Zenteno, A

    2016-01-01

    We present a study of the inner (out to $\\sim$1 R$_{\\mathrm{eff}}$) stellar populations of 9 shell galaxies. We derive stellar population parameters from long slit spectra by both analyzing the Lick indices of the galaxies and by fitting Single Stellar Population model spectra to the full galaxy spectra. The results from the two methods agree reasonably well. Many of the shell galaxies in our sample appear to have lower central $\\mathrm{Mg}_{2}$ index values than non-shell galaxies of the same central velocity dispersion, which is likely due to a past interaction event. Our shell galaxy sample shows a relation between central metallicity and velocity dispersion that is consistent with previous samples of non-shell galaxies. Analyzing the metallicity gradients in our sample, we find an average metallicity gradient of -0.16$\\pm$0.10 dex per decade in radius. We compare this with formation models to constrain the merging history of shell galaxies. We argue that our galaxies likely have undergone major mergers in...

  20. Stellar Properties of Embedded Protostars

    CERN Document Server

    White, R J; Doppmann, G W; Covey, Kevin R; Hillenbrand, L A

    2006-01-01

    (Abridged) High dispersion spectrographs on large aperture telescopes have recently allowed observers to study the stellar and accretion properties of deeply embedded young stars, commonly referred to as Class I stars. We summarize these newly determined properties and compare them with observations of more optically revealed Class II (T Tauri) stars. Class I stars have spectral types and stellar luminosities similar to those of Class II stars, suggesting similar masses and ages. Estimates of stellar luminosity and age, however, are especially uncertain given the large extinctions, scattered light emission and continuum excesses typical of Class I stars. Several candidate Class I brown dwarfs are identified. Class I stars appear to rotate more rapidly than T Tauri stars, by roughly a factor of 2. Likewise, Class I disk accretion rates are only a factor of two larger than those of T Tauri stars, less than the mass infall rates predicted by envelope models by 1-2 orders of magnitude. In at least a few cases the...

  1. Human Perception of Ambiguous Inertial Motion Cues

    Science.gov (United States)

    Zhang, Guan-Lu

    2010-01-01

    Human daily activities on Earth involve motions that elicit both tilt and translation components of the head (i.e. gazing and locomotion). With otolith cues alone, tilt and translation can be ambiguous since both motions can potentially displace the otolithic membrane by the same magnitude and direction. Transitions between gravity environments (i.e. Earth, microgravity and lunar) have demonstrated to alter the functions of the vestibular system and exacerbate the ambiguity between tilt and translational motion cues. Symptoms of motion sickness and spatial disorientation can impair human performances during critical mission phases. Specifically, Space Shuttle landing records show that particular cases of tilt-translation illusions have impaired the performance of seasoned commanders. This sensorimotor condition is one of many operational risks that may have dire implications on future human space exploration missions. The neural strategy with which the human central nervous system distinguishes ambiguous inertial motion cues remains the subject of intense research. A prevailing theory in the neuroscience field proposes that the human brain is able to formulate a neural internal model of ambiguous motion cues such that tilt and translation components can be perceptually decomposed in order to elicit the appropriate bodily response. The present work uses this theory, known as the GIF resolution hypothesis, as the framework for experimental hypothesis. Specifically, two novel motion paradigms are employed to validate the neural capacity of ambiguous inertial motion decomposition in ground-based human subjects. The experimental setup involves the Tilt-Translation Sled at Neuroscience Laboratory of NASA JSC. This two degree-of-freedom motion system is able to tilt subjects in the pitch plane and translate the subject along the fore-aft axis. Perception data will be gathered through subject verbal reports. Preliminary analysis of perceptual data does not indicate that

  2. Development of compact cold-atom sensors for inertial navigation

    CERN Document Server

    Battelier, B; Fouché, L; Chichet, L; Antoni-Micollier, L; Porte, H; Napolitano, F; Lautier, J; Landragin, A; Bouyer, P

    2016-01-01

    Inertial sensors based on cold atom interferometry exhibit many interesting features for applications related to inertial navigation, particularly in terms of sensitivity and long-term stability. However, at present the typical atom interferometer is still very much an experiment---consisting of a bulky, static apparatus with a limited dynamic range and high sensitivity to environmental effects. To be compliant with mobile applications further development is needed. In this work, we present a compact and mobile experiment, which we recently used to achieve the first inertial measurements with an atomic accelerometer onboard an aircraft. By integrating classical inertial sensors into our apparatus, we are able to operate the atomic sensor well beyond its standard operating range, corresponding to half of an interference fringe. We report atom-based acceleration measurements along both the horizontal and vertical axes of the aircraft with one-shot sensitivities of $2.3 \\times 10^{-4}\\,g$ over a range of $\\sim 0...

  3. Gait Kinematic Analysis in Water Using Wearable Inertial Magnetic Sensors

    National Research Council Canada - National Science Library

    Fantozzi, Silvia; Giovanardi, Andrea; Borra, Davide; Gatta, Giorgio

    2015-01-01

    .... The aim of the present study was to estimate the 3D joint kinematics of the lower limbs and thorax-pelvis joints in sagittal and frontal planes during underwater walking using wearable inertial and magnetic sensors...

  4. Compact Optical Inertial Tracking for Launch Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a method for developing a miniature all-optical Inertial Navigation System. In an optical INS, the rotation sensitivity depends on the area enclosed by a...

  5. Multiple equilibria of cross-equatorial Inertial jets

    Institute of Scientific and Technical Information of China (English)

    CHAO JiPing; LIU Fei

    2007-01-01

    Based on the developed Anderson and Moore's theory about cross-equatorial inertial jets and a nonlinear equivalence shallow water model, new universal functions are determined by the characters of the vortical large-scale air flow (atmosphere) or ocean current (ocean) related to the jet, then the potential vorticity and energy conservation equations along the streamline in the cross-equatorial inertial jets can be obtained. Because the governing equations are nonlinear, some limited multiple equilibria of cross-equatorial inertial jets may exist. According to the character of large-scale air flow or ocean current outside the jets, the existent criterion for multiple eqnilibria in cross-equatorial inertial jets is discussed, and two examples for multiple equilibia of nonlinear governing equations are given.

  6. Multiple equilibria of cross-equatorial Inertial jets

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the developed Anderson and Moore’s theory about cross-equatorial inertial jets and a nonlinear equivalence shallow water model, new universal functions are determined by the characters of the vortical large-scale air flow (atmosphere) or ocean current (ocean) related to the jet, then the potential vorticity and energy conservation equations along the streamline in the cross-equatorial in-ertial jets can be obtained. Because the governing equations are nonlinear, some limited multiple equi-libria of cross-equatorial inertial jets may exist. According to the character of large-scale air flow or ocean current outside the jets, the existent criterion for multiple eqnilibria in cross-equatorial inertial jets is discussed, and two examples for multiple equilibia of nonlinear governing equations are given.

  7. Nonlinear Vibration Analysis of Moving Strip with Inertial Boundary Condition

    Directory of Open Access Journals (Sweden)

    Chong-yi Gao

    2015-01-01

    Full Text Available According to the movement mechanism of strip and rollers in tandem mill, the strip between two stands was simplified to axially moving Euler beam and the rollers were simplified to the inertial component on the fixed axis rotation, namely, inertial boundary. Nonlinear vibration mechanical model of Euler beam with inertial boundary conditions was established. The transverse and longitudinal motion equations were derived based on Hamilton’s principle. Kantorovich averaging method was employed to discretize the motion equations and the inertial boundary equations, and the solutions were obtained using the modified iteration method. Depending on numerical calculation, the amplitude-frequency responses of Euler beam were determined. The axial velocity, tension, and rotational inertia have strong influences on the vibration characteristics. The results would provide an important theoretical reference to control and analyze the vertical vibration of moving strip in continuous rolling process.

  8. Bundle adjustment with raw inertial observations in UAV applications

    Science.gov (United States)

    Cucci, Davide Antonio; Rehak, Martin; Skaloud, Jan

    2017-08-01

    It is well known that accurate aerial position and attitude control is beneficial for image orientation in airborne photogrammetry. The aerial control is traditionally obtained by Kalman filtering/smoothing inertial and GNSS observations prior to the bundle-adjustment. However, in Micro Aerial Vehicles this process may result in poor attitude determination due to the limited quality of the inertial sensors, large alignment uncertainty and residual correlations between sensor biases and initial attitude. We propose to include the raw inertial observations directly into the bundle-adjustment instead of as position and attitude weighted observations from a separate inertial/GNSS fusion step. The necessary observation models are derived in detail within the context of the so called ;Dynamic Networks;. We examine different real world cases and we show that the proposed approach is superior to the established processing pipeline in challenging scenarios such as mapping in corridors and in areas where the reception of GNSS signals is denied.

  9. Inertial-particle accelerations in turbulence: a Lagrangian closure

    CERN Document Server

    Vajedi, S; Mehlig, B; Biferale, L

    2016-01-01

    The distribution of particle accelerations in turbulence is intermittent, with non-Gaussian tails that are quite different for light and heavy particles. In this article we analyse a closure scheme for the acceleration fluctuations of light and heavy inertial particles in turbulence, formulated in terms of Lagrangian correlation functions of fluid tracers. We compute the variance and the flatness of inertial particle accelerations and we discuss their dependency on the Stokes number. The closure incorporates effects induced by the Lagrangian correlations along the trajectories of fluid tracers, and its predictions agree well with results of direct numerical simulations of inertial particles in turbulence, provided that the effects induced by the inertial preferential sampling of heavy/light particles outside/inside vortices are negligible. In particular, the scheme predicts the correct functional behaviour of the acceleration variance, as a function of Stokes, as well as the presence of a minimum/maximum for ...

  10. Fusion of Inertial Navigation and Imagery Data Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovations of the Fusion of Inertial Navigation and Imagery Data are the application of the concept to the dynamic entry-interface through near-landing phases,...

  11. Backward Finite-Time Lyapunov Exponents in Inertial Flows.

    Science.gov (United States)

    Gunther, Tobias; Theisel, Holger

    2017-01-01

    Inertial particles are finite-sized objects that are carried by fluid flows and in contrast to massless tracer particles they are subject to inertia effects. In unsteady flows, the dynamics of tracer particles have been extensively studied by the extraction of Lagrangian coherent structures (LCS), such as hyperbolic LCS as ridges of the Finite-Time Lyapunov Exponent (FTLE). The extension of the rich LCS framework to inertial particles is currently a hot topic in the CFD literature and is actively under research. Recently, backward FTLE on tracer particles has been shown to correlate with the preferential particle settling of small inertial particles. For larger particles, inertial trajectories may deviate strongly from (massless) tracer trajectories, and thus for a better agreement, backward FTLE should be computed on inertial trajectories directly. Inertial backward integration, however, has not been possible until the recent introduction of the influence curve concept, which - given an observation and an initial velocity - allows to recover all sources of inertial particles as tangent curves of a derived vector field. In this paper, we show that FTLE on the influence curve vector field is in agreement with preferential particle settling and more importantly it is not only valid for small (near-tracer) particles. We further generalize the influence curve concept to general equations of motion in unsteady spatio-velocity phase spaces, which enables backward integration with more general equations of motion. Applying the influence curve concept to tracer particles in the spatio-velocity domain emits streaklines in massless flows as tangent curves of the influence curve vector field. We demonstrate the correlation between inertial backward FTLE and the preferential particle settling in a number of unsteady vector fields.

  12. Measuring postural stability with an inertial sensor: validity and sensitivity

    Directory of Open Access Journals (Sweden)

    Neville C

    2015-11-01

    Full Text Available Christopher Neville,1 Caleb Ludlow,1 Brian Rieger21Department of Physical Therapy Education, 2Upstate Concussion Center, SUNY Upstate Medical University, Syracuse, NY, USAIntroduction/purpose: To examine the concurrent validity, and sensitivity, of an inertial sensor for use in the assessment of postural sway.Methods: This was a laboratory-based, repeated-measures design with ten healthy participants. Concurrent validity was tested between an inertial sensor, forceplate, and rigid-body kinematics across three commonly used balance tests. Further, the inertial sensor measures were compared across eight commonly used tests of balance. Variables manipulated include stance position, surface condition, and eyes-open versus eyes-closed.Results: The inertial sensor was correlated to both the forceplate-derived measures (r=0.793 and rigid-body kinematics (r=0.887. Significant differences between the balance tests were observed when tested with the inertial sensor. In general, there was a three-way interactions between the three balance factors (surface, stance, and vision leading to pairwise comparisons between each balance test. The root-mean-square showed an increase across tasks of greater difficulty ranging from an average of 0.0368 with two legs, eyes-open to 0.911 when tested during tandem stance, eyes-closed tested on a foam pad.Conclusion: The new inertial sensor shows promise for use in the assessment of postural sway. Additionally, the inertial sensor appears sensitive to differences in balance tasks of varying degrees of difficulty when tested in a healthy sample of young adults. This inertial sensor may provide new opportunities for further research in the assessment of balance changes in the mild traumatic brain injury population.Keywords: balance, concussion, forceplate, posturography, accelerometer

  13. Vertical inertial piezoelectric translation device for a scanning tunneling microscope

    Science.gov (United States)

    Agraït, N.

    1992-01-01

    We report a new type of inertial translation device that uses a single piezoelectric tube. In contrast to previous inertial translation devices which must operate in horizontal position, this new design can operate in any position, even vertical. This makes possible the construction of a compact high-stability thermally compensated low temperature scanning tunneling microscope, specially suited to designs that allow for a very short tip and sample change time.

  14. Low-cost inertial measurement unit.

    Energy Technology Data Exchange (ETDEWEB)

    Deyle, Travis Jay

    2005-03-01

    Sandia National Laboratories performs many expensive tests using inertial measurement units (IMUs)--systems that use accelerometers, gyroscopes, and other sensors to measure flight dynamics in three dimensions. For the purpose of this report, the metrics used to evaluate an IMU are cost, size, performance, resolution, upgradeability and testing. The cost of a precision IMU is very high and can cost hundreds of thousands of dollars. Thus the goals and results of this project are as follows: (1) Examine the data flow in an IMU and determine a generic IMU design. (2) Discuss a high cost IMU implementation and its theoretically achievable results. (3) Discuss design modifications that would save money for suited applications. (4) Design and implement a low cost IMU and discuss its theoretically achievable results. (5) Test the low cost IMU and compare theoretical results with empirical results. (6) Construct a more streamlined printed circuit board design reducing noise, increasing capabilities, and constructing a self-contained unit. Using these results, we can compare a high cost IMU versus a low cost IMU using the metrics from above. Further, we can examine and suggest situations where a low cost IMU could be used instead of a high cost IMU for saving cost, size, or both.

  15. Motion of Inertial Observers Through Negative Energy

    CERN Document Server

    Ford, L H; Roman, Thomas A.

    1993-01-01

    Recent research has indicated that negative energy fluxes due to quantum coherence effects obey uncertainty principle-type inequalities of the form $|\\Delta E|\\,{\\Delta \\tau} \\lprox 1\\,$. Here $|\\Delta E|$ is the magnitude of the negative energy which is transmitted on a timescale $\\Delta \\tau$. Our main focus in this paper is on negative energy fluxes which are produced by the motion of observers through static negative energy regions. We find that although a quantum inequality appears to be satisfied for radially moving geodesic observers in two and four-dimensional black hole spacetimes, an observer orbiting close to a black hole will see a constant negative energy flux. In addition, we show that inertial observers moving slowly through the Casimir vacuum can achieve arbitrarily large violations of the inequality. It seems likely that, in general, these types of negative energy fluxes are not constrained by inequalities on the magnitude and duration of the flux. We construct a model of a non-gravitational ...

  16. Inertially confined fusion using heavy ion drivers

    Energy Technology Data Exchange (ETDEWEB)

    Herrmannsfeldt, W.B. (Stanford Linear Accelerator Center, Menlo Park, CA (United States)); Bangerter, R.O. (Lawrence Berkeley Lab., CA (United States)); Bock, R. (Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)); Hogan, W.J.; Lindl, J.D. (Lawrence Livermore National Lab., CA (United States))

    1991-10-01

    The various technical issues of HIF will be briefly reviewed in this paper. It will be seen that there are numerous areas in common in all the approaches to HIF. In the recent International Symposium on Heavy Ion Inertial Fusion, the attendees met in specialized workshop sessions to consider the needs for research in each area. Each of the workshop groups considered the key questions of this report: (1) Is this an appropriate time for international collaboration in HIF (2) Which problems are most appropriate for such collaboration (3) Can the sharing of target design information be set aside until other driver and systems issues are better resolved, by which time it might be supposed that there could be a relaxation of classification of target issues (4) What form(s) of collaboration are most appropriate, e.g., bilateral or multilateral (5) Can international collaboration be sensibly attempted without significant increases in funding for HIF The authors of this report share the conviction that collaboration on a broad scale is mandatory for HIF to have the resources, both financial and personnel, to progress to a demonstration experiment. Ultimately it may be possible for a single driver with the energy, power, focusibility, and pulse shape to satisfy the needs of the international community for target physics research. Such a facility could service multiple experimental chambers with a variety of beam geometries and target concepts.

  17. Inertially confined fusion using heavy ion drivers

    Energy Technology Data Exchange (ETDEWEB)

    Herrmannsfeldt, W.B. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Bangerter, R.O. [Lawrence Berkeley Lab., CA (United States); Bock, R. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Hogan, W.J.; Lindl, J.D. [Lawrence Livermore National Lab., CA (United States)

    1991-10-01

    The various technical issues of HIF will be briefly reviewed in this paper. It will be seen that there are numerous areas in common in all the approaches to HIF. In the recent International Symposium on Heavy Ion Inertial Fusion, the attendees met in specialized workshop sessions to consider the needs for research in each area. Each of the workshop groups considered the key questions of this report: (1) Is this an appropriate time for international collaboration in HIF? (2) Which problems are most appropriate for such collaboration? (3) Can the sharing of target design information be set aside until other driver and systems issues are better resolved, by which time it might be supposed that there could be a relaxation of classification of target issues? (4) What form(s) of collaboration are most appropriate, e.g., bilateral or multilateral? (5) Can international collaboration be sensibly attempted without significant increases in funding for HIF? The authors of this report share the conviction that collaboration on a broad scale is mandatory for HIF to have the resources, both financial and personnel, to progress to a demonstration experiment. Ultimately it may be possible for a single driver with the energy, power, focusibility, and pulse shape to satisfy the needs of the international community for target physics research. Such a facility could service multiple experimental chambers with a variety of beam geometries and target concepts.

  18. Asymptotic dynamics of inertial particles with memory

    CERN Document Server

    Langlois, Gabriel Provencher; Haller, George

    2014-01-01

    Recent experimental and numerical observations have shown the significance of the Basset--Boussinesq memory term on the dynamics of small spherical rigid particles (or inertial particles) suspended in an ambient fluid flow. These observations suggest an algebraic decay to an asymptotic state, as opposed to the exponential convergence in the absence of the memory term. Here, we prove that the observed algebraic decay is a universal property of the Maxey--Riley equation. Specifically, the particle velocity decays algebraically in time to a limit that is $\\mathcal O(\\epsilon)$-close to the fluid velocity, where $0<\\epsilon\\ll 1$ is proportional to the square of the ratio of the particle radius to the fluid characteristic length-scale. These results follows from a sharp analytic upper bound that we derive for the particle velocity. For completeness, we also present a first proof of existence and uniqueness of global solutions to the Maxey--Riley equation, a nonlinear system of fractional-order differential equ...

  19. Bioinspired dynamic inclination measurement using inertial sensors.

    Science.gov (United States)

    Vikas, Vishesh; Crane, Carl

    2015-04-16

    Biologically, the vestibular feedback is critical to the ability of human body to balance in different conditions. This balancing ability inspires analysis of the reference equilibrium position in dynamic environments. The research proposes and experimentally validates the concept of equilibrium for the human body modeled as an inverted pendulum, which is instrumental in explaining why we align the body along the surface normal when standing on a surface but not on an incline, and tend to lean backward or forward on non-static surfaces e.g. accelerating or decelerating bus. This equilibrium position--the dynamic equilibrium axis--is dependent only on the acceleration of surface of contact (e.g. gravity) and acts as the reference to the orientation measurements. The research also draws design inspiration from the two human ears--symmetry and plurality of inertial sensors. The vestibular dynamic inclinometer and planar vestibular dynamic inclinometer consist of multiple (two or four) symmetrically placed accelerometers and a gyroscope. The sensors measure the angular acceleration and absolute orientation, not the change in orientation, from the reference equilibrium position and are successful in separating gravity from motion for objects moving on ground. The measurement algorithm is an analytical solution that is not time-recursive, independent of body dynamics and devoid of integration errors. The experimental results for the two sensor combinations validate the theoretically (kinematics) derived analytical solution of the measurement algorithm.

  20. Dynamics of inertial particles in free jets

    Energy Technology Data Exchange (ETDEWEB)

    Casciola, C M; Gualtieri, P; Picano, F; Sardina, G [Dipartimento di Meccanica e Aeronautica, Sapienza University, Via Eudossiana 18, 00184 Rome (Italy); Troiani, G, E-mail: carlomassimo.casciola@uniroma1.it [ENEA C R Casaccia, Via Anguillarese 301, 00123 Rome (Italy)

    2010-12-15

    Turbulent mixing of small and diluted inertial particles presents many peculiar and unexpected features such as preferential segregation at small scales, i.e. clustering or, in wall flows, preferential wall accumulation, i.e. turbophoresis, which are induced by the multi-scale features of the turbulence in the carrier fluid. In the context of multi-phase flows, the effect of turbulence on particle distributions was commonly addressed in simplified geometries as in homogeneous or channel flows. The present paper discusses the dynamics of suspensions with different inertia in the far field of turbulent axisymmetric jets by means of direct numerical simulations. The jet is a well-known constant Reynolds number flow where the characteristic length scale grows linearly with distance from the jet origin, while the characteristic velocity decays in inverse proportion. These features, combined with the finite inertia, induce peculiar non-equilibrium effects on the spatial distribution of the particles. They range from spatially developing small-scale clustering, due to the multi-scale nature of the turbulent fluctuations, to self-similarity of the mean particle velocity profile, presumably collapsing on a one-parameter family of shapes parameterized in terms of the local large-scale Stokes number. The properties presented here are the most evident features of this most interesting system, where intermittency and spatial inhomogeneity interact to induce even subtler effects of spatial segregation, which certainly deserve further investigation.

  1. Gorgon simulations of Magnetized Liner Inertial Fusion

    Science.gov (United States)

    Roeltgen, Jonathan; Jennings, Christopher; Sefkow, Adam; Slutz, Stephen

    2012-10-01

    Substantial fusion yields are predicted with pulsed power machines driving cylindrical liner implosions with preheated and magnetized deuterium-tritium [S.A. Slutz et al Phys. Plasmas 17, 056303 (2010)]. The Rayleigh-Taylor instability is the most likely mechanism that could degrade the fusion yield of this concept which we call Magnetized Liner Inertial Fusion (MagLIF). Gorgon is a 3D magnetohydrodynamics code that is well suited to simulating the effects of 3D Magneto-Rayleigh-Taylor instabilities. It has successfully simulated wire array z-pinches in 3D. We plan to use Gorgon to simulate the MagLIF concept in 3D, but first we are performing 1D simulations to test the essential physics necessary to simulate the MagLIF concept, for example bremsstrahlung losses from the fuel and the inhibition of transport by the magnetic field. We will present 1D Gorgon results of optimized MagLIF yields as a function of drive current.

  2. GPS free navigation inspired by insects through monocular camera and inertial sensors

    Science.gov (United States)

    Liu, Yi; Liu, J. G.; Cao, H.; Huang, Y.

    2015-12-01

    Navigation without GPS and other knowledge of environment have been studied for many decades. Advance technology have made sensors more compact and subtle that can be easily integrated into micro and hand-hold device. Recently researchers found that bee and fruit fly have an effectively and efficiently navigation mechanism through optical flow information and process only with their miniature brain. We present a navigation system inspired by the study of insects through a calibrated camera and other inertial sensors. The system utilizes SLAM theory and can be worked in many GPS denied environment. Simulation and experimental results are presented for validation and quantification.

  3. Implementing agreement on a co-operative program on inertial fusion energy

    Energy Technology Data Exchange (ETDEWEB)

    Latkowski, J; Hogan, W; Meier, W

    2000-01-04

    The Programme to be carried out by the Contracting Parties within the framework of this Agreement shall consist of co-operative research, development, demonstrations and exchanges of information regarding inertial fusion energy (IFE). This shall include: (1) Nuclear Technology, (2) Fusion Materials, (3) Environment, Safety and Economics, (4) Laser Drivers, (5) Ion Beam Drivers and Beam/Plasma Interactions, (6) Target Production, Injection and Tracking, (7) Fusion Diagnostics, (8) Driver/Plasma Interactions, (9) Fast Ignition and (10) Power Plant Design Studies. Annexes to this agreement will describe specific tasks in each area.

  4. OSIRIS and SOMBRERO Inertial Fusion Power Plant Designs, Volume 2: Designs, Assessments, and Comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W. R.; Bieri, R. L.; Monsler, M. J.; Hendricks, C. D.; Laybourne, P.; Shillito, K. R.

    1992-03-01

    This is a comprehensive design study of two Inertial Fusion Energy (IFE) electric power plants. Conceptual designs are presented for a fusion reactor (called Osiris) using an induction-linac heavy-ion beam driver, and another (called SOMBRERO) using a KrF laser driver. The designs covered all aspects of IFE power plants, including the chambers, heat transport and power conversion systems, balance-of-plant facilities, target fabrication, target injection and tracking, as well as the heavy-ion and KrF drivers. The point designs were assessed and compared in terms of their environmental & safety aspects, reliability and availability, economics, and technology development needs.

  5. An Implementation of Error Minimization Position Estimate in Wireless Inertial Measurement Unit using Modification ZUPT

    Directory of Open Access Journals (Sweden)

    Adytia Darmawan

    2016-12-01

    Full Text Available Position estimation using WIMU (Wireless Inertial Measurement Unit is one of emerging technology in the field of indoor positioning systems. WIMU can detect movement and does not depend on GPS signals. The position is then estimated using a modified ZUPT (Zero Velocity Update method that was using Filter Magnitude Acceleration (FMA, Variance Magnitude Acceleration (VMA and Angular Rate (AR estimation. Performance of this method was justified on a six-legged robot navigation system. Experimental result shows that the combination of VMA-AR gives the best position estimation.

  6. Response of a lithium fall to an inertially confined fusion microexplosion

    Energy Technology Data Exchange (ETDEWEB)

    Hovingh, J.; Blink, J.; Glenn, L.

    1978-05-31

    One of the most difficult technology problems in an inertially confined fusion reactor is the survival of the structure from the repeated stresses caused by the microexplosion products. To mitigate the damage from the microexplosion products, a thick lithium fall can be circulated in front of the structure. This fall will absorb the short-ranged products and moderate and attenuate the neutrons. This paper discusses the response of the fall to the microexplosion products, and estimates the resulting loading and stresses in the first structural wall.

  7. Young and Exotic Stellar Zoo

    Science.gov (United States)

    2005-03-01

    constellation Ara (the Altar). It was discovered in 1961 from Australia by Swedish astronomer Bengt Westerlund, who later moved from there to become ESO Director in Chile (1970 - 74). This cluster is behind a huge interstellar cloud of gas and dust, which blocks most of its visible light. The dimming factor is more than 100,000 - and this is why it has taken so long to uncover the true nature of this particular cluster. In 2001, the team of astronomers identified more than a dozen extremely hot and peculiar massive stars in the cluster, so-called "Wolf-Rayet" stars. They have since studied Westerlund 1 extensively with various ESO telescopes. They used images from the Wide Field Imager (WFI) attached to the 2.2-m ESO/MPG as well as from the SUperb Seeing Imager 2 (SuSI2) camera on the ESO 3.5-m New Technology Telescope (NTT). From these observations, they were able to identify about 200 cluster member stars. To establish the true nature of these stars, the astronomers then performed spectroscopic observations of about one quarter of them. For this, they used the Boller & Chivens spectrograph on the ESO 1.52-m telescope and the ESO Multi-Mode Instrument (EMMI) on the NTT. An Exotic Zoo These observations have revealed a large population of very bright and massive, quite extreme stars. Some would fill the solar system space within the orbit of Saturn (about 2,000 times larger than the Sun!), others are as bright as a million Suns. Westerlund 1 is obviously a fantastic stellar zoo, with a most exotic population and a true astronomical bonanza. All stars identified are evolved and very massive, spanning the full range of stellar oddities from Wolf-Rayet stars, OB supergiants, Yellow Hypergiants (nearly as bright as a million Suns) and Luminous Blue Variables (similar to the exceptional Eta Carinae object - see ESO PR 31/03). All stars so far analysed in Westerlund 1 weigh at least 30-40 times more than the Sun. Because such stars have a rather short life - astronomically speaking

  8. On the universal stellar law

    Science.gov (United States)

    Krot, Alexander

    In this work, we consider a statistical theory of gravitating spheroidal bodies to derive and develop the universal stellar law for extrasolar systems. Previously, the statistical theory for a cosmogonic body forming (so-called spheroidal body)has been proposed [1-3]. This theory starts from the conception for forming a spheroidal body inside a gas-dust protoplanetary nebula; it permits us to derive the form of distribution functions, mass density, gravitational potentials and strengths both for immovable and rotating spheroidal bodies as well as to find the distribution function of specific angular momentum[1-3]. If we start from the conception for forming a spheroidal body as a protostar (in particular, proto-Sun) inside a prestellar (presolar) nebula then the derived distribution functions of particle (as well as the mass density of an immovable spheroidal body) characterizes the first stage of evolution: from a prestellar molecular cloud (the presolar nebula) to the forming core of protostar (the proto-Sun) together with its shell as a stellar nebula (the solar nebula). This work derives the equation of state of an ideal stellar substance based on conception of gravitating spheroidal body. Using this equation, we obtain the universal stellar law (USL) for the planetary systems connecting temperature, size and mass of each of stars. This work also considers the Solar corona in the connection with USL. Then it is accounting under calculation of the ratio of temperature of the Solar corona to effective temperature of the Sun’ surfaceand modification of USL. To test justice of the modified USLfor different types of stars, the temperature of stellar corona is estimated. The prediction of parameters of stars is carrying out by means of the modified USL,as well as the Hertzsprung-Russell’s dependence [5-7]is derivedby means of USL directly. This paper also shows that knowledge of some characteristics for multi-planet extrasolar systems refines own parameters of

  9. On plasma radiative properties in stellar conditions

    CERN Document Server

    Turck-Chièze, S; Gilles, D; Loisel, G; Piau, L; 10.1016/j.hedp.2009.06.007

    2012-01-01

    The knowledge of stellar evolution is evolving quickly thanks to an increased number of opportunities to scrutinize the stellar internal plasma properties by stellar seismology and by 1D and 3D simulations. These new tools help us to introduce the internal dynamical phenomena in stellar modeling. A proper inclusion of these processes supposes a real confidence in the microscopic physics used, partly checked by solar or stellar acoustic modes. In the present paper we first recall which fundamental physics has been recently verified by helioseismology. Then we recall that opacity is an important ingredient of the secular evolution of stars and we point out why it is necessary to measure absorption coefficients and degrees of ionization in the laboratory for some well identified astrophysical conditions. We examine two specific experimental conditions which are accessible to large laser facilities and are suitable to solve some interesting questions of the stellar community: are the solar internal radiative inte...

  10. Properties of stellar activity cycles

    CERN Document Server

    Korhonen, Heidi

    2015-01-01

    The current photometric datasets, that span decades, allow for studying long-term cycles on active stars. Complementary Ca H&K observations give information also on the cycles of normal solar-like stars, which have significantly smaller, and less easily detectable, spots. In the recent years, high precision space-based observations, for example from the Kepler satellite, have allowed also to study the sunspot-like spot sizes in other stars. Here I review what is known about the properties of the cyclic stellar activity in other stars than our Sun.

  11. Improvements on analytic modelling of stellar spots

    CERN Document Server

    Montalto, M; Oshagh, M; Boisse, I; Bruno, G; Santos, N C

    2014-01-01

    In this work we present the solution of the stellar spot problem using the Kelvin-Stokes theorem. Our result is applicable for any given location and dimension of the spots on the stellar surface. We present explicitely the result up to the second degree in the limb darkening law. This technique can be used to calculate very efficiently mutual photometric effects produced by eclipsing bodies occulting stellar spots and to construct complex spot shapes.

  12. Stellar Tools for High Resolution Population Synthesis

    Science.gov (United States)

    Chávez, M.; Bertone, E.; Rodríguez-Merino, L.; Buzzoni, A.

    2005-12-01

    We present preliminary results of the application of a new stellar library of high-resolution synthetic spectra (based upon ATLAS9 and SYNTHE codes developed by R. L. Kurucz) in the calculation of the ultraviolet-optical spectral energy distribution of simple stellar populations (SSPs). For this purpose, the library has been coupled with Buzzoni's population synthesis code. Part of this paper is also devoted to illustrate quantitatively the extent to which synthetic stellar libraries represent real stars.

  13. Artificial Neural Networks in Stellar Astronomy

    Directory of Open Access Journals (Sweden)

    R. K. Gulati

    2001-01-01

    Full Text Available Next generation of optical spectroscopic surveys, such as the Sloan Digital Sky Survey and the 2 degree field survey, will provide large stellar databases. New tools will be required to extract useful information from these. We show the applications of artificial neural networks to stellar databases. In another application of this method, we predict spectral and luminosity classes from the catalog of spectral indices. We assess the importance of such methods for stellar populations studies.

  14. Energetics of nearby stellar bow shocks

    CERN Document Server

    Benaglia, Paula

    2012-01-01

    The latest survey of stellar bow shocks (Peri et al. 2012) lists 28 candidates detected at IR wavelengths, associated with massive, early-type stars up to 3 kpc, along with the geometrical parameters of the structures found. I present here some considerations on the energetics involved, after the estimation of stellar wind power, infrared flux, stellar bolometric luminosity and radio flux limits for each source. The best candidates for relativistic particle acceleration are highlighted.

  15. New Age Indicators for Stellar Populations

    Institute of Scientific and Technical Information of China (English)

    KONG Xu; CHENG Fu-Zhen

    2000-01-01

    We apply the method of principal component analysis to a sample of simple stellar populations to select some age sensitive spectral indices. Besides the well-known age sensitive index Hβ, we also find some new age sensitive indices, G4300 and Fe4383, C24668, and Mgb. In addition, we find that these spectral indices sensitive to age depend on the metallicity of stellar population, Hβ and G4300 are more suitable to determine the age of loy metallicity stellar population, while C24668 and Mgb are more suitable to the high metallicity stellar population.

  16. Disks around young stellar objects

    Indian Academy of Sciences (India)

    H C Bhatt

    2011-07-01

    By 1939, when Chandrasekhar’s classic monograph on the theory of Stellar Structure was published, although the need for recent star formation was fully acknowledged, no one had yet recognized an object that could be called a star in the process of being born. Young stellar objects (YSOs), as pre-main-sequence stars, were discovered in the 1940s and 1950s. Infrared excess emission and intrinsic polarization observed in these objects in the 1960s and 1970s indicated that they are surrounded by flattened disks. The YSO disks were seen in direct imaging only in the 1980s. Since then, high-resolution optical imaging with HST, near-infrared adaptive optics on large groundbased telescopes, mm and radiowave interferometry have been used to image disks around a large number of YSOs revealing disk structure with ever-increasing detail and variety. The disks around YSOs are believed to be the sites of planet formation and a few such associations have now been confirmed. The observed properties of the disk structure and their evolution, that have very important consequences for the theory of star and planet formation, are discussed.

  17. Maximum stellar iron core mass

    Indian Academy of Sciences (India)

    F W Giacobbe

    2003-03-01

    An analytical method of estimating the mass of a stellar iron core, just prior to core collapse, is described in this paper. The method employed depends, in part, upon an estimate of the true relativistic mass increase experienced by electrons within a highly compressed iron core, just prior to core collapse, and is significantly different from a more typical Chandrasekhar mass limit approach. This technique produced a maximum stellar iron core mass value of 2.69 × 1030 kg (1.35 solar masses). This mass value is very near to the typical mass values found for neutron stars in a recent survey of actual neutron star masses. Although slightly lower and higher neutron star masses may also be found, lower mass neutron stars are believed to be formed as a result of enhanced iron core compression due to the weight of non-ferrous matter overlying the iron cores within large stars. And, higher mass neutron stars are likely to be formed as a result of fallback or accretion of additional matter after an initial collapse event involving an iron core having a mass no greater than 2.69 × 1030 kg.

  18. Technology.

    Science.gov (United States)

    Online-Offline, 1998

    1998-01-01

    Focuses on technology, on advances in such areas as aeronautics, electronics, physics, the space sciences, as well as computers and the attendant progress in medicine, robotics, and artificial intelligence. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books,…

  19. An Inertial-Fusion Z-Pinch Power Plant Concept

    Energy Technology Data Exchange (ETDEWEB)

    DERZON,MARK S.; ROCHAU,GARY E.; DEGROOT,J.; OLSON,CRAIG L.; PETERSON,P.; PETERSON,R.R.; SLUTZ,STEPHEN A.; ZAMORA,ANTONIO J.

    2000-12-15

    With the promising new results of fast z-pinch technology developed at Sandia National Laboratories, we are investigating using z-pinch driven high-yield Inertial Confinement Fusion (ICF) as a fusion power plant energy source. These investigations have led to a novel fusion system concept based on an attempt to separate many of the difficult fusion engineering issues and a strict reliance on existing technology, or a reasonable extrapolation of existing technology, wherever possible. In this paper, we describe the main components of such a system with a focus on the fusion chamber dynamics. The concept works with all of the electrically-coupled ICF proposed fusion designs. It is proposed that a z-pinch driven ICF power system can be feasibly operated at high yields (1 to 30 GJ) with a relatively low pulse rate (0.01-0.1 Hz). To deliver the required current from the rep-rated pulse power driver to the z-pinch diode, a Recyclable Transmission Line (RTL) and the integrated target hardware are fabricated, vacuum pumped, and aligned prior to loading for each power pulse. In this z-pinch driven system, no laser or ion beams propagate in the chamber such that the portion of the chamber outside the RTL does not need to be under vacuum. Additionally, by utilizing a graded-density solid lithium or fluorine/lithium/beryllium eutectic (FLiBe) blanket between the source and the first-wall the system can breed its own fuel absorb a large majority of the fusion energy released from each capsule and shield the first-wall from a damaging neutron flux. This neutron shielding significantly reduces the neutron energy fluence at the first-wall such that radiation damage should be minimal and will not limit the first-wall lifetime. Assuming a 4 m radius, 8 m tall cylindrical chamber design with an 80 cm thick spherical FLiBe blanket, our calculations suggest that a 20 cm thick 6061-T6 Al chamber wall will reach the equivalent uranium ore radioactivity level within 100 years after a 30

  20. An Inertial-Fusion Z-Pinch Power Plant Concept

    Energy Technology Data Exchange (ETDEWEB)

    DERZON,MARK S.; ROCHAU,GARY E.; DEGROOT,J.; OLSON,CRAIG L.; PETERSON,P.; PETERSON,R.R.; SLUTZ,STEPHEN A.; ZAMORA,ANTONIO J.

    2000-12-15

    With the promising new results of fast z-pinch technology developed at Sandia National Laboratories, we are investigating using z-pinch driven high-yield Inertial Confinement Fusion (ICF) as a fusion power plant energy source. These investigations have led to a novel fusion system concept based on an attempt to separate many of the difficult fusion engineering issues and a strict reliance on existing technology, or a reasonable extrapolation of existing technology, wherever possible. In this paper, we describe the main components of such a system with a focus on the fusion chamber dynamics. The concept works with all of the electrically-coupled ICF proposed fusion designs. It is proposed that a z-pinch driven ICF power system can be feasibly operated at high yields (1 to 30 GJ) with a relatively low pulse rate (0.01-0.1 Hz). To deliver the required current from the rep-rated pulse power driver to the z-pinch diode, a Recyclable Transmission Line (RTL) and the integrated target hardware are fabricated, vacuum pumped, and aligned prior to loading for each power pulse. In this z-pinch driven system, no laser or ion beams propagate in the chamber such that the portion of the chamber outside the RTL does not need to be under vacuum. Additionally, by utilizing a graded-density solid lithium or fluorine/lithium/beryllium eutectic (FLiBe) blanket between the source and the first-wall the system can breed its own fuel absorb a large majority of the fusion energy released from each capsule and shield the first-wall from a damaging neutron flux. This neutron shielding significantly reduces the neutron energy fluence at the first-wall such that radiation damage should be minimal and will not limit the first-wall lifetime. Assuming a 4 m radius, 8 m tall cylindrical chamber design with an 80 cm thick spherical FLiBe blanket, our calculations suggest that a 20 cm thick 6061-T6 Al chamber wall will reach the equivalent uranium ore radioactivity level within 100 years after a 30

  1. Sea ice inertial oscillations in the Arctic Basin

    Directory of Open Access Journals (Sweden)

    F. Gimbert

    2012-10-01

    Full Text Available An original method to quantify the amplitude of inertial motion of oceanic and ice drifters, through the introduction of a non-dimensional parameter M defined from a spectral analysis, is presented. A strong seasonal dependence of the magnitude of sea ice inertial oscillations is revealed, in agreement with the corresponding annual cycles of sea ice extent, concentration, thickness, advection velocity, and deformation rates. The spatial pattern of the magnitude of the sea ice inertial oscillations over the Arctic Basin is also in agreement with the sea ice thickness and concentration patterns. This argues for a strong interaction between the magnitude of inertial motion on one hand, the dissipation of energy through mechanical processes, and the cohesiveness of the cover on the other hand. Finally, a significant multi-annual evolution towards greater magnitudes of inertial oscillations in recent years, in both summer and winter, is reported, thus concomitant with reduced sea ice thickness, concentration and spatial extent.

  2. Inertial waves in a differentially rotating spherical shell

    CERN Document Server

    Baruteau, C

    2012-01-01

    We investigate the properties of small-amplitude inertial waves propagating in a differentially rotating incompressible fluid contained in a spherical shell. For cylindrical and shellular rotation profiles and in the inviscid limit, inertial waves obey a second-order partial differential equation of mixed type. Two kinds of inertial modes therefore exist, depending on whether the hyperbolic domain where characteristics propagate covers the whole shell or not. The occurrence of these two kinds of inertial modes is examined, and we show that the range of frequencies at which inertial waves may propagate is broader than with solid-body rotation. Using high-resolution calculations based on a spectral method, we show that, as with solid-body rotation, singular modes with thin shear layers following short-period attractors still exist with differential rotation. They exist even in the case of a full sphere. In the limit of vanishing viscosities, the width of the shear layers seems to weakly depend on the global bac...

  3. Shoulder and elbow joint angle tracking with inertial sensors.

    Science.gov (United States)

    El-Gohary, Mahmoud; McNames, James

    2012-09-01

    Wearable inertial systems have recently been used to track human movement in and outside of the laboratory. Continuous monitoring of human movement can provide valuable information relevant to individuals' level of physical activity and functional ability. Traditionally, orientation has been calculated by integrating the angular velocity from gyroscopes. However, a small drift in the measured velocity leads to increasing integration error over time. To compensate that drift, complementary data from accelerometers are normally fused into tracking systems using the Kalman or extended Kalman filter. In this study, we combine kinematic models designed for control of robotic arms with state-space methods to continuously estimate the angles of human shoulder and elbow using two wearable inertial measurement units. We use the unscented Kalman filter to implement the nonlinear state-space inertial tracker. Shoulder and elbow joint angles obtained from 8 subjects using our inertial tracker were compared to the angles obtained from an optical-tracking reference system. On average, there was an RMS angle error of less than 8° for all shoulder and elbow angles. The average correlation coefficient for all movement tasks among all subjects was r ≥ 0.95 . This agreement between our inertial tracker and the optical reference system was obtained for both regular and fast-speed movement of the arm. The same method can be used to track movement of other joints.

  4. Inertial effect on spin–orbit coupling and spin transport

    Energy Technology Data Exchange (ETDEWEB)

    Basu, B., E-mail: sribbasu@gmail.com; Chowdhury, Debashree, E-mail: debashreephys@gmail.com

    2013-08-15

    We theoretically study the renormalization of inertial effects on the spin dependent transport of conduction electrons in a semiconductor by taking into account the interband mixing on the basis of k{sup →}⋅p{sup →} perturbation theory. In our analysis, for the generation of spin current we have used the extended Drude model where the spin–orbit coupling plays an important role. We predict enhancement of the spin current resulting from the renormalized spin–orbit coupling effective in our model in cubic and non-cubic crystals. Attention has been paid to clarify the importance of gauge fields in the spin transport of this inertial system. A theoretical proposition of a perfect spin filter has been done through the Aharonov–Casher like phase corresponding to this inertial system. For a time dependent acceleration, effect of k{sup →}⋅p{sup →} perturbation on the spin current and spin polarization has also been addressed. Furthermore, achievement of a tunable source of polarized spin current through the non uniformity of the inertial spin–orbit coupling strength has also been discussed. -- Highlights: •Study of the renormalization of inertial spin dependent transport of electrons. •Enhancement of the spin current due to the renormalized spin–orbit coupling. •A theoretical proposition of a perfect spin filter. •For a time dependent acceleration, spin current, spin polarization is addressed.

  5. Near-inertial parametric subharmonic instability of internal wave beams

    Science.gov (United States)

    Karimi, Hussain H.; Akylas, T. R.

    2017-07-01

    Parametric subharmonic instability (PSI) of internal wave beams in a uniformly stratified fluid is discussed, for the case where the beam frequency is nearly twice the inertial frequency due to background rotation. Compared with generic PSI, beams of finite width are expected on physical grounds to be more vulnerable to subharmonic perturbations of near-inertial frequency, as these disturbances have small group velocity and stay in contact with the underlying beam longer, thus extracting more energy. A weakly nonlinear theory for such near-inertial PSI is developed in the "distinguished limit" where the effects of triad nonlinear interactions, dispersion, and viscous dissipation are equally important. This model is used to examine the linear stability of a uniform beam to infinitesimal perturbations under a "pump-wave" approximation, as well as the nonlinear development of PSI that takes into account the effect of the growing perturbations on the beam evolution. Near-inertial PSI is possible for beams of general locally confined profile, in sharp contrast to generic PSI which can arise only for quasimonochromatic beams whose profile comprises a sinusoidal carrier modulated by a locally confined envelope. The theoretical predictions are consistent with earlier numerical simulations of semidiurnal internal tide beams generated over the continental shelf break at latitudes above and below the critical value 28 .8∘N , at which the subharmonic semidiurnal frequency matches the local inertial frequency.

  6. Comparison of male and female lower limb segment inertial properties.

    Science.gov (United States)

    Challis, John H; Winter, Samantha L; Kuperavage, Adam J

    2012-10-11

    Many studies have examined human segmental inertial parameters, but these studies have focused more on male rather than female data. The purpose of this study was to determine the lower limb segmental inertial parameters for a large sample (n>1500) of both males and females. The participants in this study were those measured as part of a survey of the anthropometry of US army personnel. The sample comprised 1774 males (mean height 1.756±0.079 m, mean mass of 78.49±0.11 kg, and mean age of 27.21±6.81 years), and 2208 females (mean height 1.629±0.072 m, mean mass of 62.01±0.08 kg, and mean age of 26.18±5.70 years). Anthropometric measurements were used to determine the inertial properties of the lower limb segments by modeling them as series of geometric solids. An analysis of variance revealed that the normalized inertial parameters for each of the segments were statistically significantly different (p>0.001) between the two groups. The time for each segment to swing through the range of motion of the swing phase of gait, produced shorter swing times for the male segments. The differences between the segmental inertial properties for the sexes have implications for how these parameters are customized to experimental subjects.

  7. Advanced Integration of WiFi and Inertial Navigation Systems for Indoor Mobile Positioning

    Science.gov (United States)

    Evennou, Frédéric; Marx, François

    2006-12-01

    This paper presents an aided dead-reckoning navigation structure and signal processing algorithms for self localization of an autonomous mobile device by fusing pedestrian dead reckoning and WiFi signal strength measurements. WiFi and inertial navigation systems (INS) are used for positioning and attitude determination in a wide range of applications. Over the last few years, a number of low-cost inertial sensors have become available. Although they exhibit large errors, WiFi measurements can be used to correct the drift weakening the navigation based on this technology. On the other hand, INS sensors can interact with the WiFi positioning system as they provide high-accuracy real-time navigation. A structure based on a Kalman filter and a particle filter is proposed. It fuses the heterogeneous information coming from those two independent technologies. Finally, the benefits of the proposed architecture are evaluated and compared with the pure WiFi and INS positioning systems.

  8. Advanced Integration of WiFi and Inertial Navigation Systems for Indoor Mobile Positioning

    Directory of Open Access Journals (Sweden)

    Evennou Frédéric

    2006-01-01

    Full Text Available This paper presents an aided dead-reckoning navigation structure and signal processing algorithms for self localization of an autonomous mobile device by fusing pedestrian dead reckoning and WiFi signal strength measurements. WiFi and inertial navigation systems (INS are used for positioning and attitude determination in a wide range of applications. Over the last few years, a number of low-cost inertial sensors have become available. Although they exhibit large errors, WiFi measurements can be used to correct the drift weakening the navigation based on this technology. On the other hand, INS sensors can interact with the WiFi positioning system as they provide high-accuracy real-time navigation. A structure based on a Kalman filter and a particle filter is proposed. It fuses the heterogeneous information coming from those two independent technologies. Finally, the benefits of the proposed architecture are evaluated and compared with the pure WiFi and INS positioning systems.

  9. The Stellar IMF from turbulent fragmentation

    Science.gov (United States)

    Padoan, P.; Nordlund, A.

    2001-01-01

    In this paper they conclude that turbulent fragmentation is unavoidable in super-sonically turbulent molecular clouds, and given the success of the present model to predict the observed shape of the Stellar IMF, they conclude that turbulent fragmentation is essential to the origin of the stellar IMF.

  10. Astrospheres and Solar-like Stellar Winds

    Directory of Open Access Journals (Sweden)

    Wood Brian E.

    2004-07-01

    Full Text Available Stellar analogs for the solar wind have proven to be frustratingly difficult to detect directly. However, these stellar winds can be studied indirectly by observing the interaction regions carved out by the collisions between these winds and the interstellar medium (ISM. These interaction regions are called "astrospheres", analogous to the "heliosphere" surrounding the Sun. The heliosphere and astrospheres contain a population of hydrogen heated by charge exchange processes that can produce enough H I Ly alpha absorption to be detectable in UV spectra of nearby stars from the Hubble Space Telescope (HST. The amount of astrospheric absorption is a diagnostic for the strength of the stellar wind, so these observations have provided the first measurements of solar-like stellar winds. Results from these stellar wind studies and their implications for our understanding of the solar wind are reviewed here. Of particular interest are results concerning the past history of the solar wind and its impact on planetary atmospheres.

  11. The impact of companions on stellar evolution

    CERN Document Server

    De Marco, Orsola

    2016-01-01

    Stellar astrophysicists are increasingly taking into account the effects of orbiting companions on stellar evolution. New discoveries, many thanks to systematic time-domain surveys, have underlined the role of binary star interactions in a range of astrophysical events, including some that were previously interpreted as due uniquely to single stellar evolution. Here, we review classical binary phenomena such as type Ia supernovae, and discuss new phenomena such as intermediate luminosity transients, gravitational wave-producing double black holes, or the interaction between stars and their planets. Finally, we examine the reassessment of well-known phenomena in light of interpretations that include both single and binary stars, for example supernovae of type Ib and Ic or luminous blue variables. At the same time we contextualise the new discoveries within the framework and nomenclature of the corpus of knowledge on binary stellar evolution. The last decade has heralded an era of revival in stellar astrophysic...

  12. Geolocation Technologies Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Magnoli, D E

    2003-06-02

    This paper is the final report for LL998 In Situ Sensing Subtask 7 (Geo-location) undertaken for NNSA NA-22 enabling technologies R&D for Counterproliferation Detection. A few state-of-the-art resolution parameters are presented for accelerometers, indoor and outdoor GPS (Global Positioning Satellite) systems, and INSs (Inertial Navigation Systems). New technologies are described, including one which has demonstrated the ability to track within a building to a resolution of under a foot.

  13. Overview of recent tritium target filling, layering, and material testing at Los Alamos national laboratory in support of inertial fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ebey, P. S.; Dole, J. M.; Geller, D. A.; Hoffer, J. K.; Morris, J.; Nobile, A.; Schoonover, J. R.; Wilson, D. [MS-C927, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Bonino, M.; Harding, D.; Sangster, C.; Shmayda, W. [Laboratory for Laser Energetics LLE, Univ. of Rochester, 250 East River Road, Rochester, NY 14623 (United States); Nikroo, A.; Sheliak, J. D. [General Atomics GA (United States); Burmann, J.; Cook, B.; Letts, S.; Sanchez, J. [Lawrence Livermore National Laboratory LLNL (United States)

    2008-07-15

    The Tritium Science and Engineering (AET-3) Group at Los Alamos National Laboratory (LANL) performs a variety of activities to support Inertial Fusion (IF) research - both to further fundamental fusion science and to develop technologies in support of Inertial Fusion Energy (IFE) power generation. Inertial fusion ignition target designs have a smooth spherical shell of cryogenic Deuterium-Tritium (DT) solid contained within a metal or plastic shell that is a few mm in diameter. Fusion is attained by imploding these shells under the symmetric application of energy beams. For IFE targets the DT solid must also survive the process of injecting it into the power plant reactor. Non-ignition IF targets often require a non-cryogenic DT gas fill of a glass or polymeric shell. In this paper an overview will be given of recent LANL activities to study cryogenic DT layering, observe tritium exposure effects on IF relevant materials, and fill targets in support of IF implosion experiments. (authors)

  14. Capillary-inertial colloidal catapults upon drop coalescence

    Science.gov (United States)

    Chavez, Roger L.; Liu, Fangjie; Feng, James J.; Chen, Chuan-Hua

    2016-07-01

    Surface energy released upon drop coalescence is known to power the self-propelled jumping of liquid droplets on superhydrophobic solid surfaces, and the jumping droplets can additionally carry colloidal payloads toward self-cleaning. Here, we show that drop coalescence on a spherical particle leads to self-propelled launching of the particle from virtually any solid surface. The main prerequisite is an intermediate wettability of the particle, such that the momentum from the capillary-inertial drop coalescence process can be transferred to the particle. By momentum conservation, the launching velocity of the particle-drop complex is proportional to the capillary-inertial velocity based on the drop radius and to the fraction of the liquid mass in the total mass. The capillary-inertial catapult is not only an alternative mechanism for removing colloidal contaminants, but also a useful model system for studying ballistospore launching.

  15. Gait analysis using floor markers and inertial sensors.

    Science.gov (United States)

    Do, Tri Nhut; Suh, Young Soo

    2012-01-01

    In this paper, a gait analysis system which estimates step length and foot angles is proposed. A measurement unit, which consists of a camera and inertial sensors, is installed on a shoe. When the foot touches the floor, markers are recognized by the camera to obtain the current position and attitude. A simple planar marker with 4,096 different codes is used. These markers printed on paper are placed on the floor. When the foot is moving off the floor, the position and attitude are estimated using an inertial navigation algorithm. For accurate estimation, a smoother is proposed, where vision information and inertial sensor data are combined. Through experiments, it is shown that the proposed system can both track foot motion and estimate step length.

  16. Gait Analysis Using Floor Markers and Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Young Soo Suh

    2012-02-01

    Full Text Available In this paper, a gait analysis system which estimates step length and foot angles is proposed. A measurement unit, which consists of a camera and inertial sensors, is installed on a shoe. When the foot touches the floor, markers are recognized by the camera to obtain the current position and attitude. A simple planar marker with 4,096 different codes is used. These markers printed on paper are placed on the floor. When the foot is moving off the floor, the position and attitude are estimated using an inertial navigation algorithm. For accurate estimation, a smoother is proposed, where vision information and inertial sensor data are combined. Through experiments, it is shown that the proposed system can both track foot motion and estimate step length.

  17. Inertial frames without the relativity principle: breaking Lorentz symmetry

    CERN Document Server

    Baccetti, Valentina; Visser, Matt

    2013-01-01

    We investigate inertial frames in the absence of Lorentz invariance, reconsidering the usual group structure implied by the relativity principle. We abandon the relativity principle, discarding the group structure for the transformations between inertial frames, while requiring these transformations to be at least linear (to preserve homogeneity). In theories with a preferred frame (aether), the set of transformations between inertial frames forms a groupoid/pseudogroup instead of a group, a characteristic essential to evading the von Ignatowsky theorems. In order to understand the dynamics, we also demonstrate that the transformation rules for energy and momentum are in general affine. We finally focus on one specific and compelling model implementing a minimalist violation of Lorentz invariance.

  18. Moving toward low frequencies active vibration control with inertial actuators

    Science.gov (United States)

    Cinquemani, S.; Costa, A.; Resta, F.

    2017-04-01

    In applications of vibration suppression, control forces ideally act on the structure increasing its damping. While the frequency response of the structure is guaranteed to have a positive real part under ideal conditions, in practice a stability limit exists when inertial actuators are used. In this case the system response is no longer guaranteed to be positive real and so the control system may become unstable at high gains. Moreover, traditional approaches suggest the use of inertial actuators only if its natural frequency is well below the natural frequency of the structure, thus preventing their use at low frequencies. This paper proposes an interesting technique to enlarge the operational range to lower frequencies and to allow the use of inertial actuators. The approach is numerically tested and experimentally validated on a test rig.

  19. Single-pulse dynamics and flow rates of inertial micropumps

    CERN Document Server

    Govyadinov, A N; Markel, D P; Torniainen, E D

    2015-01-01

    Bubble-driven inertial pumps are a novel method of moving liquids through microchannels. We combine high-speed imaging, computational fluid dynamics (CFD) simulations and an effective one-dimensional model to study the fundamentals of inertial pumping. Single-pulse flow through 22 x 17 um2 U-shaped channels containing 4-um polystyrene tracer beads has been imaged with a high-speed camera. The results are used to calibrate the CFD and one-dimensional models to extract an effective bubble strength. Then the frequency dependence of inertial pumping is studied both experimentally and numerically. The pump efficiency is found to gradually decrease once the successive pulses start to overlap in time.

  20. Detecting inertial effects with airborne matter-wave interferometry

    CERN Document Server

    Geiger, Remi; Stern, Guillaume; Zahzam, Nassim; Cheinet, Patrick; Battelier, Baptiste; Villing, André; Moron, Frédéric; Lours, Michel; Bidel, Yannick; Bresson, Alexandre; Landragin, Arnaud; Bouyer, Philippe

    2011-01-01

    Inertial sensors relying on atom interferometry offer a breakthrough advance in a variety of applications, such as inertial navigation, gravimetry or ground- and space-based tests of fundamental physics. These instruments require a quiet environment to reach their performance and using them outside the laboratory remains a challenge. Here we report the first operation of an airborne matter-wave accelerometer set up aboard a 0g plane and operating during the standard gravity (1g) and microgravity (0g) phases of the flight. At 1g, the sensor can detect inertial effects more than 300 times weaker than the typical acceleration fluctuations of the aircraft. We describe the improvement of the interferometer sensitivity in 0g, which reaches 2 x 10-4 ms-2 / \\surdHz with our current setup. We finally discuss the extension of our method to airborne and spaceborne tests of the Universality of free fall with matter waves.

  1. Global Observer-Based Attitude Controller Using Direct Inertial Measurements

    Directory of Open Access Journals (Sweden)

    Saâdi Bouhired

    2014-04-01

    Full Text Available In this work, we address the problem of global attitude control using direct inertial measurements. When using direct inertial measurement to observe the rigid body attitude, it is shown that due to a geometrical obstruction, it is impossible to achieve global asymptotic stability. In fact, for a particular initial condition the tracking error quaternion converges to a pure imaginary quaternion formed by an eigenvector of a characteristic matrix related to the inertial constant and known vectors. Our proposition consists of adding a dynamic signal to force the rigid body to escape from such a situation. The proposed observer-based controller is synthesized based on a single Lyapunov function and a stability analysis shows that the controller stabilizes globally and asymptotically the rigid body attitude at the desired one. The effectiveness of the proposed observer-based controller is confirmed by simulation results.

  2. Detecting inertial effects with airborne matter-wave interferometry.

    Science.gov (United States)

    Geiger, R; Ménoret, V; Stern, G; Zahzam, N; Cheinet, P; Battelier, B; Villing, A; Moron, F; Lours, M; Bidel, Y; Bresson, A; Landragin, A; Bouyer, P

    2011-09-20

    Inertial sensors relying on atom interferometry offer a breakthrough advance in a variety of applications, such as inertial navigation, gravimetry or ground- and space-based tests of fundamental physics. These instruments require a quiet environment to reach their performance and using them outside the laboratory remains a challenge. Here we report the first operation of an airborne matter-wave accelerometer set up aboard a 0g plane and operating during the standard gravity (1g) and microgravity (0g) phases of the flight. At 1g, the sensor can detect inertial effects more than 300 times weaker than the typical acceleration fluctuations of the aircraft. We describe the improvement of the interferometer sensitivity in 0g, which reaches 2 x 10-4 ms-2 / √Hz with our current setup. We finally discuss the extension of our method to airborne and spaceborne tests of the Universality of free fall with matter waves.

  3. Plumes in stellar convection zones

    CERN Document Server

    Zahn, J P

    1999-01-01

    All numerical simulations of compressible convection reveal the presence of strong downwards directed flows. Thanks to helioseismology, such plumes have now been detected also at the top of the solar convection zone, on super- granular scales. Their properties may be crudely described by adopting Taylor's turbulent entrainment hypothesis, whose validity is well established under various conditions. Using this model, one finds that the strong density stratification does not prevent the plumes from traversing the whole convection zone, and that they carry upwards a net energy flux (Rieutord & Zahn 1995). They penetrate to some extent in the adjacent stable region, where they establish a nearly adiabatic stratification. These plumes have a strong impact on the dynamics of stellar convection zones, and they play probably a key role in the dynamo mechanism.

  4. Multiplicity in Early Stellar Evolution

    CERN Document Server

    Reipurth, Bo; Boss, Alan P; Goodwin, Simon P; Rodriguez, Luis Felipe; Stassun, Keivan G; Tokovinin, Andrei; Zinnecker, Hans

    2014-01-01

    Observations from optical to centimeter wavelengths have demonstrated that multiple systems of two or more bodies is the norm at all stellar evolutionary stages. Multiple systems are widely agreed to result from the collapse and fragmentation of cloud cores, despite the inhibiting influence of magnetic fields. Surveys of Class 0 protostars with mm interferometers have revealed a very high multiplicity frequency of about 2/3, even though there are observational difficulties in resolving close protobinaries, thus supporting the possibility that all stars could be born in multiple systems. Near-infrared adaptive optics observations of Class I protostars show a lower binary frequency relative to the Class 0 phase, a declining trend that continues through the Class II/III stages to the field population. This loss of companions is a natural consequence of dynamical interplay in small multiple systems, leading to ejection of members. We discuss observational consequences of this dynamical evolution, and its influenc...

  5. Collisionless Relaxation of Stellar Systems

    Science.gov (United States)

    Kandrup, Henry E.

    1999-08-01

    The objective of the work summarized here has been to exploit and extend ideas from plasma physics and accelerator dynamics to formulate a unified description of collisionless relaxation of stellar systems that views violent relaxation, Landau damping, and phase mixing as (manifestations of) a single phenomenon. This approach embraces the fact that the collisionless Boltzmann equation (CBE), the basic object of the theory, is an infinite-dimensional Hamiltonian system, with the distribution function f playing the role of the fundamental dynamical variable, and that, interpreted appropriately, an evolution described by the CBE is no different fundamentally from an evolution described by any other Hamiltonian system. Equilibrium solutions f0 correspond to extremal points of the Hamiltonian subject to the constraints associated with Liouville's Theorem. Stable equilibria correspond to energy minima. The evolution of a system out of equilibrium involves (in general nonlinear) phase space oscillations which may - or may not - interfere destructively so as to damp away.

  6. Hydrodynamic stability and stellar oscillations

    Indian Academy of Sciences (India)

    H M Antia

    2011-07-01

    Chandrasekhar’s monograph on Hydrodynamic and hydromagnetic stability, published in 1961, is a standard reference on linear stability theory. It gives a detailed account of stability of fluid flow in a variety of circumstances, including convection, stability of Couette flow, Rayleigh–Taylor instability, Kelvin–Helmholtz instability as well as the Jean’s instability for star formation. In most cases he has extended these studies to include effects of rotation and magnetic field. In a later paper he has given a variational formulation for equations of non-radial stellar oscillations. This forms the basis for helioseismic inversion techniques as well as extension to include the effect of rotation, magnetic field and other large-scale flows using a perturbation treatment.

  7. Stellar atmospheres, atmospheric extension and fundamental parameters: weighing stars using the stellar mass index

    CERN Document Server

    Neilson, Hilding R; Norris, Ryan; Kloppenborg, Brian; Lester, John B

    2016-01-01

    One of the great challenges in understanding stars is measuring their masses. The best methods for measuring stellar masses include binary interaction, asteroseismology and stellar evolution models, but these methods are not ideal for red giant and supergiant stars. In this work, we propose a novel method for inferring stellar masses of evolved red giant and supergiant stars using interferometric and spectrophotometric observations combined with spherical model stellar atmospheres to measure what we call the stellar mass index, defined as the ratio between the stellar radius and mass. The method is based on the correlation between different measurements of angular diameter, used as a proxy for atmospheric extension, and fundamental stellar parameters. For a given star, spectrophotometry measures the Rosseland angular diameter while interferometric observations generally probe a larger limb-darkened angular diameter. The ratio of these two angular diameters is proportional to the relative extension of the stel...

  8. Decoherence and Multipartite Entanglement of Non-Inertial Observers

    Institute of Scientific and Technical Information of China (English)

    M. Ramzan

    2012-01-01

    The decoherence effect on multipartite entanglement in non-inertial frames is investigated.The GHZ state is considered to be shared between partners with one partner in the inertial frame whereas the other two are in accelerated frames.One-tangle and π-tangles are used to quantify the entanglement of the multipartite system influenced by phase damping and phase flip channels.It is seen that for the phase damping channel,entanglement sudden death (ESD) occurs for p > 0.5 in the infinite acceleration limit.On the other hand,in the case of the phase flip channel,ESD behavior occurs at p =0.5.It is also seen that entanglement sudden birth (ESB) occurs in the case of phase flip channel just after ESD,i.e.p > 0.5.Furthermore,it is seen that the effect of the environment on multipartite entanglement is much stronger than that of the acceleration of non-inertial frames.%The decoherence effect on multipartite entanglement in non-inertial frames is investigated. The GHZ state is considered to be shared between partners with one partner in the inertial frame whereas the other two are in accelerated frames. One-tangle and w-tangles are used to quantify the entanglement of the multipartite system influenced by phase damping and phase Hip channels. It is seen that for the phase damping channel, entanglement sudden death (ESD) occurs for p > 0.5 in the inSnite acceleration limit. On the other hand, in the case of the phase Hip channel, ESD behavior occurs at p = 0.5. It is also seen that entanglement sudden birth (ESB) occurs in the case of phase flip channel just after ESD, I.e. p > 0.5. Furthermore, it is seen that the effect of the environment on multipartite entanglement is much stronger than that of the acceleration of non-inertial frames.

  9. Analysis of Magnetic Fields in Inertial Alfven Wave Collisions

    CERN Document Server

    Drake, Dereth J; Shanken, Brian C; Howes, Gregory G; Skiff, Frederick; Kletzing, Craig A; Carter, Troy A; Dorfman, Seth

    2014-01-01

    Turbulence in astrophysical and space plasmas is dominated by the nonlinear interaction of counterpropagating Alfven waves. Most Alfven wave turbulence theories have been based on ideal plasma models, such as incompressible MHD, for Alfven waves at large scales. However, in the inertial Alfven wave regime (vA > vthe), relevant to magnetospheric plasmas, how the turbulent nonlinear interactions are modified by the dispersive nature of the waves remains to be explored. Here we present the first laboratory evidence of the nonlinear interaction in the inertial regime. A comparison is made with the theory for MHD Alfven waves.

  10. Direct Measurement of Particle Inertial Migration in Rectangular Microchannels

    CERN Document Server

    Hood, Kaitlyn; Di Carlo, Dino; Roper, Marcus

    2015-01-01

    Particles traveling at high velocities through microfluidic channels migrate across streamlines due to inertial lift forces. There are contradictory theories predicting how the inertial lift force depends on flow parameters, but little experimental evidence by which to validate theory. Here we directly measure particle migration velocities and show agreement with numerical simulations and a two-term asymptotic theory that contains no unmeasured parameters. Our data also highlight the previously unconsidered effect of migration forces that act on particles before they enter the microchannel.

  11. Inertial fusion energy; L'energie de fusion inertielle

    Energy Technology Data Exchange (ETDEWEB)

    Decroisette, M.; Andre, M.; Bayer, C.; Juraszek, D. [CEA Bruyeres-le-Chatel, Dir. des Systemes d' Information (CEA/DIF), 91 (France); Le Garrec, B. [CEA Centre d' Etudes Scientifiques et Techniques d' Aquitaine, 33 - Le Barp (France); Deutsch, C. [Paris-11 Univ., 91 - Orsay (France); Migus, A. [Institut d' Optique Centre scientifique, 91 - Orsay (France)

    2005-07-01

    We first recall the scientific basis of inertial fusion and then describe a generic fusion reactor with the different components: the driver, the fusion chamber, the material treatment unit, the target factory and the turbines. We analyse the options proposed at the present time for the driver and for target irradiation scheme giving the state of art for each approach. We conclude by the presentation of LMJ (laser Megajoule) and NIF (national ignition facility) projects. These facilities aim to demonstrate the feasibility of laboratory DT ignition, first step toward Inertial Fusion Energy. (authors)

  12. Sampling and Control Circuit Board for an Inertial Measurement Unit

    Science.gov (United States)

    Chelmins, David T (Inventor); Powis, Richard T., Jr. (Inventor); Sands, Obed (Inventor)

    2016-01-01

    A circuit board that serves as a control and sampling interface to an inertial measurement unit ("IMU") is provided. The circuit board is also configured to interface with a local oscillator and an external trigger pulse. The circuit board is further configured to receive the external trigger pulse from an external source that time aligns the local oscillator and initiates sampling of the inertial measurement device for data at precise time intervals based on pulses from the local oscillator. The sampled data may be synchronized by the circuit board with other sensors of a navigation system via the trigger pulse.

  13. Technology

    Directory of Open Access Journals (Sweden)

    Xu Jing

    2016-01-01

    Full Text Available The traditional answer card reading method using OMR (Optical Mark Reader, most commonly, OMR special card special use, less versatile, high cost, aiming at the existing problems proposed a method based on pattern recognition of the answer card identification method. Using the method based on Line Segment Detector to detect the tilt of the image, the existence of tilt image rotation correction, and eventually achieve positioning and detection of answers to the answer sheet .Pattern recognition technology for automatic reading, high accuracy, detect faster

  14. An Inertial Dual-State State Estimator for Precision Planetary Landing with Hazard Detection and Avoidance

    Science.gov (United States)

    Bishop, Robert H.; DeMars, Kyle; Trawny, Nikolas; Crain, Tim; Hanak, Chad; Carson, John M.; Christian, John

    2016-01-01

    The navigation filter architecture successfully deployed on the Morpheus flight vehicle is presented. The filter was developed as a key element of the NASA Autonomous Landing and Hazard Avoidance Technology (ALHAT) project and over the course of 15 free fights was integrated into the Morpheus vehicle, operations, and flight control loop. Flight testing completed by demonstrating autonomous hazard detection and avoidance, integration of an altimeter, surface relative velocity (velocimeter) and hazard relative navigation (HRN) measurements into the onboard dual-state inertial estimator Kalman flter software, and landing within 2 meters of the vertical testbed GPS-based navigation solution at the safe landing site target. Morpheus followed a trajectory that included an ascent phase followed by a partial descent-to-landing, although the proposed filter architecture is applicable to more general planetary precision entry, descent, and landings. The main new contribution is the incorporation of a sophisticated hazard relative navigation sensor-originally intended to locate safe landing sites-into the navigation system and employed as a navigation sensor. The formulation of a dual-state inertial extended Kalman filter was designed to address the precision planetary landing problem when viewed as a rendezvous problem with an intended landing site. For the required precision navigation system that is capable of navigating along a descent-to-landing trajectory to a precise landing, the impact of attitude errors on the translational state estimation are included in a fully integrated navigation structure in which translation state estimation is combined with attitude state estimation. The map tie errors are estimated as part of the process, thereby creating a dual-state filter implementation. Also, the filter is implemented using inertial states rather than states relative to the target. External measurements include altimeter, velocimeter, star camera, terrain relative

  15. A 6 D.O.F. opto-inertial tracker for virtual reality experiments in microgravity

    Science.gov (United States)

    Zaoui, Mohamed; Wormell, Dean; Altshuler, Yury; Foxlin, Eric; McIntyre, Joseph

    2001-08-01

    Gravity plays a role in many different levels of human motor behavior. It dictates the laws of motion of our body and limbs, as well as of the objects in the external world with which we wish to interact. The dynamic interaction of our body with the world is molded within gravity's constraints. The role played by gravity in the perception of visual stimuli and the elaboration of human movement is an active research theme in the field of Neurophysiology. Conditions of microgravity, coupled with techniques from the world of virtual reality, provide a unique opportunity to address these questions concerning the function of the human sensorimotor system [1]. The ability to measure movements of the head and to update in real time the visual scene presented to the subject based on these measurements is a key element in producing a realistic virtual environment. A variety of head-tracking hardware exists on the market today [2-4], but none seem particularly well suited to the constraints of working with a space station environment. Nor can any of the existing commercial systems meet the more stringent requirements for physiological experimentation (high accuracy, high resolution, low jitter, low lag) in a wireless configuration. To this end, we have developed and tested a hybrid opto-inertial 6 degree-of-freedom tracker based on existing inertial technology [5-8]. To confirm that the inertial components and algorithms will function properly, this system was tested in the microgravity conditions of parabolic flight. Here we present the design goals of this tracker, the system configuration and the results of 0g and 1g testing.

  16. Tanscranial Threshold of Inertial Cavitation Induced by Diagnosticc Ultrasound and Microbubbles

    NARCIS (Netherlands)

    Liu, J.; Gao, S.; Porter, T.R.; Everbach, C; Shi, W.; Vignon, F.; Powers, J.; Lof, J.; Turner, J.; Xie, F.

    2011-01-01

    Background: Inertial cavitation may cause hazardous bioeffects whileusing ultrasound and microbubble mediated thrombolysis. The purposeof this study was to investigate the influence of ultrasound pulselength and temporal bone on inertial cavitation thresholds within the brain utilizing transtemporal

  17. The Mercury Project: A High Average Power, Gas-Cooled Laser For Inertial Fusion Energy Development

    Energy Technology Data Exchange (ETDEWEB)

    Bayramian, A; Armstrong, P; Ault, E; Beach, R; Bibeau, C; Caird, J; Campbell, R; Chai, B; Dawson, J; Ebbers, C; Erlandson, A; Fei, Y; Freitas, B; Kent, R; Liao, Z; Ladran, T; Menapace, J; Molander, B; Payne, S; Peterson, N; Randles, M; Schaffers, K; Sutton, S; Tassano, J; Telford, S; Utterback, E

    2006-11-03

    Hundred-joule, kilowatt-class lasers based on diode-pumped solid-state technologies, are being developed worldwide for laser-plasma interactions and as prototypes for fusion energy drivers. The goal of the Mercury Laser Project is to develop key technologies within an architectural framework that demonstrates basic building blocks for scaling to larger multi-kilojoule systems for inertial fusion energy (IFE) applications. Mercury has requirements that include: scalability to IFE beamlines, 10 Hz repetition rate, high efficiency, and 10{sup 9} shot reliability. The Mercury laser has operated continuously for several hours at 55 J and 10 Hz with fourteen 4 x 6 cm{sup 2} ytterbium doped strontium fluoroapatite (Yb:S-FAP) amplifier slabs pumped by eight 100 kW diode arrays. The 1047 nm fundamental wavelength was converted to 523 nm at 160 W average power with 73% conversion efficiency using yttrium calcium oxy-borate (YCOB).

  18. High pressure inertial focusing for separating and concentrating bacteria at high throughput

    Science.gov (United States)

    Cruz, J.; Hooshmand Zadeh, S.; Graells, T.; Andersson, M.; Malmström, J.; Wu, Z. G.; Hjort, K.

    2017-08-01

    Inertial focusing is a promising microfluidic technology for concentration and separation of particles by size. However, there is a strong correlation of increased pressure with decreased particle size. Theory and experimental results for larger particles were used to scale down the phenomenon and find the conditions that focus 1 µm particles. High pressure experiments in robust glass chips were used to demonstrate the alignment. We show how the technique works for 1 µm spherical polystyrene particles and for Escherichia coli, not being harmful for the bacteria at 50 µl min-1. The potential to focus bacteria, simplicity of use and high throughput make this technology interesting for healthcare applications, where concentration and purification of a sample may be required as an initial step.

  19. Strapdown inertial systems applications for tactical missiles (stand-off missiles)

    Science.gov (United States)

    Puech

    1986-06-01

    Strapdown Inertial Systems (SDIS) are particularly well suited for tactical standoff missile applications. This certainty was made clear by several years of theoretical design work and trials. Initial theoretical work made wide use of parameters giving detailed definition of missile trajectories and motions as obtained from measurements made on weapon systems then in development or production. Sensors (principally gyroscopes) were laboratory tested. These preliminary design efforts led to selection of various technologies such as the laser gyro and the mechanical gyro, each being adapted to the weapon system in question. Share-out of functions between various equipment items was defined. Comparison of the advantages and disadvantages of these technologies shows that today the laser gyro is principally retained for high and medium range levels of precision, with the mechanical (spin-stabilized) gyro serving in the medium and low precision range. Since requirements are ever increasing in the fields of dynamic performance and robustness, it is here that most progress is expected.

  20. Advanced Optical Inertial Reference Unit with 100 Nanoradian Stability, Two-axis

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    ATA Sensors and Systems produces precision angular rate sensors, state-of-the-art optical inertial reference units, fast steering mirrors, inertial measurement u-nits, actuators and controls used in long-range optical systems and laser communications and space qualified subsystems for satellite imaging and inertial guidance.

  1. Magnetic Modulation of Stellar Angular Momentum Loss

    CERN Document Server

    Garraffo, Cecilia; Cohen, Ofer

    2014-01-01

    Angular Momentum Loss is important for understanding astrophysical phenomena such as stellar rotation, magnetic activity, close binaries, and cataclysmic variables. Magnetic breaking is the dominant mechanism in the spin down of young late-type stars. We have studied angular momentum loss as a function of stellar magnetic activity. We argue that the complexity of the field and its latitudinal distribution are crucial for angular momentum loss rates. In this work we discuss how angular momentum is modulated by magnetic cycles, and how stellar spin down is not just a simple function of large scale magnetic field strength.

  2. Flow damping in stellarators close to quasisymmetry

    CERN Document Server

    Calvo, Ivan; Velasco, J L; Alonso, J Arturo

    2014-01-01

    Quasisymmetric stellarators are a type of optimized stellarators for which flows are undamped to lowest order in an expansion in the normalized Larmor radius. However, perfect quasisymmetry is impossible. Since large flows may be desirable as a means to reduce turbulent transport, it is important to know when a stellarator can be considered to be sufficiently close to quasisymmetry. The answer to this question depends strongly on the size of the spatial gradients of the deviation from quasisymmetry and on the collisionality regime. Recently, formal criteria for closeness to quasisymmetry have been derived in a variety of situations. In particular, the case of deviations with large gradients was solved in the $1/\

  3. Inertial Particle Migration in the Presence of a Permeate Flow

    Science.gov (United States)

    Garcia, Mike; Singelton, Amanda; Pennathur, Sumita

    2016-11-01

    Tangential Flow Filtration (TFF) is a rapid and efficient method for the filtration and separation of suspensions of particles such as viruses, bacteria or cellular material. Enhancing the efficacy of TFF not only requires a detailed understanding of particle transport mechanisms, but also the interactions between these mechanisms and a porous wall. In this work, we numerically and experimentally explore the mechanisms of inertial particle migration in the presence of a permeate flow through the porous walls of a microchannel. Numerically, we develop a force balance model to understand the competition between permeate and inertial forces and the resultant consequences on the particle equilibrium location. Experimentally, we fabricated MEMS TFF devices to study the migration of 5, 10 and 15 µm fluorescent polystyrene beads in straight channels with perpendicular permeate flow rates up to 90% of the inlet flow rate. We find that the permeate flow directly influences the inertial focusing position of the particles, both as a function of downstream channel position and ratio of inlet to outlet flow rate. Comparing experiments to our model, we can identify inertial, viscous and a co-dominant regimes.

  4. Rotating saddle trap: A Coriolis force in an inertial frame

    CERN Document Server

    Kirillov, Oleg N

    2015-01-01

    Particles in rotating saddle potentials exhibit precessional motion which, up to now, has been explained by explicit computation. We show that this precession is due to a hidden Coriolis-like force which, unlike the standard Coriolis force, is present in the inertial frame. We do so by finding a hodograph-like "guiding center" transformation using the method of normal form.

  5. Inertial drives for micro- and nanorobots: analytical study

    Science.gov (United States)

    Buechi, Roland; Zesch, Wolfgang; Codourey, Alain; Siegwart, Roland Y.

    1995-12-01

    The need for high precision robots dedicated to the assembly of microsystems has led to the design of new kinds of actuators able to reach very high positional accuracy over large distances. Among these, inertial sliders have received considerably interest in the last years. They have the advantage of being based on a simple principle that leads to a simple mechanical design. However, because they are based on the nonlinearity of friction, it is not easy to predict their stepsize repeatability. In order to understand the most important parameters affecting the precision of inertial drives, a theoretical study of a 1 degree of freedom inertial slider has been established. Analytical formulas describing the influence of different parameters, such as static and dynamic friction and mass distribution, have been developed. The effect of applied functions (sawtooth and parabolic), have also been studied. The theoretical cut off frequency has been found for each of the different waveforms, allowing us to predict the maximal and minimal working frequencies for the system. Thus, for each curve form, the repeatability of inertial sliders can be evaluated taking into account the uncertainties in the friction coefficients. The best suited waveforms for given constraints can therefore be selected. Simulations carried out from this have been successfully compared to experimental results.

  6. Collapse of Incoherent Light Beams in Inertial Bulk Kerr Media

    DEFF Research Database (Denmark)

    Bang, Ole; Edmundson, Darran; Królikowski, Wieslaw

    1999-01-01

    We use the coherent density function theory to show that partially coherent beams are unstable and may collapse in inertial bulk Kerr media. The threshold power for collapse, and its dependence on the degree of coherence, is found analytically and checked-numerically. The internal dynamics of the...

  7. Automatic Identification of Inertial Sensors on the Human Body Segments

    NARCIS (Netherlands)

    Weenk, D.; Beijnum, van B.J.F.; Veltink, P.H.

    2011-01-01

    In the last few years, inertial sensors (accelerometers and gyroscopes) in combination with magnetic sensors was proven to be a suitable ambulatory alternative to traditional human motion tracking systems based on optical position measurements. While accurate full 6 degrees of freedom information is

  8. Single stream inertial focusing in a straight microchannel.

    Science.gov (United States)

    Wang, Xiao; Zandi, Matthew; Ho, Chia-Chi; Kaval, Necati; Papautsky, Ian

    2015-04-21

    In the past two decades, microfluidics has become of great value in precisely aligning cells or microparticles within fluids. Microfluidic techniques use either external forces or sheath flow to focus particulate samples, and face the challenges of complex instrumentation design and limited throughput. The burgeoning field of inertial microfluidics brings single-position focusing functionality at throughput orders of magnitude higher than previously available. However, most inertial microfluidic focusers rely on cross-sectional flow-induced drag force to achieve single-position focusing, which inevitably complicates the device design and operation. In this work, we present an inertial microfluidic focuser that uses inertial lift force as the only driving force to focus microparticles into a single position. We demonstrate single-position focusing of different sized microbeads and cells with 95-100% efficiency, without the need for secondary flow, sheath flow or external forces. We further integrate this device with a laser counting system to form a sheathless flow cytometer, and demonstrated counting of microbeads with 2200 beads s(-1) throughput and 7% coefficient of variation. Cells can be completely recovered and remain viable after passing our integrated cytometry system. Our approach offers a number of benefits, including simplicity in fundamental principle and geometry, convenience in design, modification and integration, flexibility in focusing of different samples, high compatibility with real-world cellular samples as well as high-precision and high-throughput single-position focusing.

  9. Approximate Inertial Manifolds for Chemotaxis-Growth System

    Institute of Scientific and Technical Information of China (English)

    Hong LUO; Zhilin PU

    2012-01-01

    The long-time behaviour of solution to chemotaxis-growth system with Neumann condition is considered in this paper.The approximate inertial manifolds of such equations are constructed based on the contraction principle,and the orders of approximations of the manifolds to the global attractor are derived.

  10. Automatic Identification of Inertial Sensors on the Human Body Segments

    NARCIS (Netherlands)

    Weenk, D.; van Beijnum, Bernhard J.F.; Veltink, Petrus H.

    In the last few years, inertial sensors (accelerometers and gyroscopes) in combination with magnetic sensors was proven to be a suitable ambulatory alternative to traditional human motion tracking systems based on optical position measurements. While accurate full 6 degrees of freedom information is

  11. Sensitivity Study of Strapdown Inertial Sensors in High Performance Applications

    Science.gov (United States)

    1980-12-01

    system error varied with a change in heading 7K. ( xii 1 SENSITIVITY STUDY OF STRAPDOWN INERTIAL SENSORS IN HIGH PERFORMANCE APPLICATIONS I. Introduction...given in Tabla 10. 23 State Meaning o Basic Altitude Damped INS x(1) Error in East Longitude 5.7735 x 1O Ŗ arc min x(2) Error in North Latitude

  12. Analysis of indoor rowing motion using wearable inertial sensors

    NARCIS (Netherlands)

    Bosch, Stephan; Shoaib, Muhammad; Geerlings, Stephen; Buit, Lennart; Meratnia, Nirvana; Havinga, Paul

    2015-01-01

    In this exploratory work the motion of rowers is analyzed while rowing on a rowing machine. This is performed using inertial sensors that measure the orientation at several positions on the body. Using these measurements, this work provides a preliminary analysis of the differences between experienc

  13. Inertial effect on spin-orbit coupling and spin transport

    Science.gov (United States)

    Basu, B.; Chowdhury, Debashree

    2013-08-01

    We theoretically study the renormalization of inertial effects on the spin dependent transport of conduction electrons in a semiconductor by taking into account the interband mixing on the basis of k→ṡp→ perturbation theory. In our analysis, for the generation of spin current we have used the extended Drude model where the spin-orbit coupling plays an important role. We predict enhancement of the spin current resulting from the renormalized spin-orbit coupling effective in our model in cubic and non-cubic crystals. Attention has been paid to clarify the importance of gauge fields in the spin transport of this inertial system. A theoretical proposition of a perfect spin filter has been done through the Aharonov-Casher like phase corresponding to this inertial system. For a time dependent acceleration, effect of k→ ṡp→ perturbation on the spin current and spin polarization has also been addressed. Furthermore, achievement of a tunable source of polarized spin current through the non uniformity of the inertial spin-orbit coupling strength has also been discussed.

  14. Ambulatory position and orientation tracking fusing magnetic and inertial sensing

    NARCIS (Netherlands)

    Roetenberg, Daniel; Slycke, Per J.; Veltink, Peter H.

    2007-01-01

    This paper presents the design and testing of a portable magnetic system combined with miniature inertial sensors for ambulatory 6 degrees of freedom ( DOF) human motion tracking. The magnetic system consists of three orthogonal coils, the source, fixed to the body and 3-D magnetic sensors, fixed to

  15. Inertial particle focusing in microchannels with gradually changing geometrical structures

    Science.gov (United States)

    Fan, Liang-Liang; Yan, Qing; Guo, Jing; Zhao, Hong; Zhao, Liang; Zhe, Jiang

    2017-01-01

    The influence of gradually changing geometrical structures on the inertial focusing of particles is systematically investigated by numerical simulations and experiments in this paper. The Saffman lift force, often ignored in the straight microchannel, becomes strong in microchannels with gradually changing geometrical structures, affecting the lateral migration of particles in the microchannels. In comparison with microchannels that have straight and gradually constricting structures, microchannels with gradually expanding structures focus all the particles in a much narrower bandwidth due to the combined effect of the Saffman lift force and the inertial lift force at the appropriate flow rates. Additionally, the influence of the different arrangements of gradually expanding structures on the inertial focusing of particles was also studied. Results suggest that to achieve the single-stream inertial focusing of particles, gradually expanding structures should be designed on one side or symmetrically on two sides of the microchannel. This study is of importance for the better design of the microchannels utilized for the efficient separation and manipulation of particle-related applications, such as microflow cytometry.

  16. Systematic Calibration for Ultra-High Accuracy Inertial Measurement Units.

    Science.gov (United States)

    Cai, Qingzhong; Yang, Gongliu; Song, Ningfang; Liu, Yiliang

    2016-06-22

    An inertial navigation system (INS) has been widely used in challenging GPS environments. With the rapid development of modern physics, an atomic gyroscope will come into use in the near future with a predicted accuracy of 5 × 10(-6)°/h or better. However, existing calibration methods and devices can not satisfy the accuracy requirements of future ultra-high accuracy inertial sensors. In this paper, an improved calibration model is established by introducing gyro g-sensitivity errors, accelerometer cross-coupling errors and lever arm errors. A systematic calibration method is proposed based on a 51-state Kalman filter and smoother. Simulation results show that the proposed calibration method can realize the estimation of all the parameters using a common dual-axis turntable. Laboratory and sailing tests prove that the position accuracy in a five-day inertial navigation can be improved about 8% by the proposed calibration method. The accuracy can be improved at least 20% when the position accuracy of the atomic gyro INS can reach a level of 0.1 nautical miles/5 d. Compared with the existing calibration methods, the proposed method, with more error sources and high order small error parameters calibrated for ultra-high accuracy inertial measurement units (IMUs) using common turntables, has a great application potential in future atomic gyro INSs.

  17. Systematic Calibration for Ultra-High Accuracy Inertial Measurement Units

    Directory of Open Access Journals (Sweden)

    Qingzhong Cai

    2016-06-01

    Full Text Available An inertial navigation system (INS has been widely used in challenging GPS environments. With the rapid development of modern physics, an atomic gyroscope will come into use in the near future with a predicted accuracy of 5 × 10−6°/h or better. However, existing calibration methods and devices can not satisfy the accuracy requirements of future ultra-high accuracy inertial sensors. In this paper, an improved calibration model is established by introducing gyro g-sensitivity errors, accelerometer cross-coupling errors and lever arm errors. A systematic calibration method is proposed based on a 51-state Kalman filter and smoother. Simulation results show that the proposed calibration method can realize the estimation of all the parameters using a common dual-axis turntable. Laboratory and sailing tests prove that the position accuracy in a five-day inertial navigation can be improved about 8% by the proposed calibration method. The accuracy can be improved at least 20% when the position accuracy of the atomic gyro INS can reach a level of 0.1 nautical miles/5 d. Compared with the existing calibration methods, the proposed method, with more error sources and high order small error parameters calibrated for ultra-high accuracy inertial measurement units (IMUs using common turntables, has a great application potential in future atomic gyro INSs.

  18. Parameter Identification Method for SINS Initial Alignment under Inertial Frame

    Directory of Open Access Journals (Sweden)

    Haijian Xue

    2016-01-01

    Full Text Available The performance of a strapdown inertial navigation system (SINS largely depends on the accuracy and rapidness of the initial alignment. The conventional alignment method with parameter identification has been already applied widely, but it needs to calculate the gyroscope drifts through two-position method; then the time of initial alignment is greatly prolonged. For this issue, a novel self-alignment algorithm by parameter identification method under inertial frame for SINS is proposed in this paper. Firstly, this coarse alignment method using the gravity in the inertial frame as a reference is discussed to overcome the limit of dynamic disturbance on a rocking base and fulfill the requirement for the fine alignment. Secondly, the fine alignment method by parameter identification under inertial frame is formulated. The theoretical analysis results show that the fine alignment model is fully self-aligned with no external reference information and the gyrodrifts can be estimated in real time. The simulation results demonstrate that the proposed method can achieve rapid and highly accurate initial alignment for SINS.

  19. Inertial waves in a laboratory model of the Earth's core

    Science.gov (United States)

    Triana, Santiago Andres

    2011-12-01

    A water-filled three-meter diameter spherical shell built as a model of the Earth's core shows evidence of precessionally forced flows and, when spinning the inner sphere differentially, inertial modes are excited. We identified the precessionally forced flow to be primarily the spin-over inertial mode, i.e., a uniform vorticity flow whose rotation axis is not aligned with the container's rotation axis. A systematic study of the spin-over mode is carried out, showing that the amplitude dependence on the Poincare number is in qualitative agreement with Busse's laminar theory while its phase differs significantly, likely due to topographic effects. At high rotation rates free shear layers concentrating most of the kinetic energy of the spin-over mode have been observed. When spinning the inner sphere differentially, a total of 12 inertial modes have been identified, reproducing and extending previous experimental results. The inertial modes excited appear ordered according to their azimuthal drift speed as the Rossby number is varied.

  20. Fresnel-Fizeau drag: Invisibility conditions for all inertial observers

    Science.gov (United States)

    Halimeh, Jad C.; Thompson, Robert T.

    2016-03-01

    It was recently shown [J. C. Halimeh et al., Phys. Rev. A 93, 013850 (2016), 10.1103/PhysRevA.93.013850] that as a result of the Doppler effect, inherently dispersive single-frequency ideal free-space invisibility cloaks in relative motion to an observer can only cloak light whose frequency in the cloak frame coincides with the operational frequency of the cloak, although an infinite number of such rays exist for any cloak motion. In this article, we show analytically and through ray-tracing simulations that even though this relationship can be relaxed by simplifying the ideal invisibility cloak into a broadband amplitude cloak, Fresnel-Fizeau drag uncloaks the phase of light in the inertial frame of the cloak thereby compromising its amplitude cloaking in all other inertial frames. In other words, only an invisibility device that perfectly cloaks both the amplitude and the phase of light in its own inertial frame will also (perfectly) cloak this light in any other inertial frame. The same conclusion lends itself to invisible objects that are not cloaks, such as the invisible sphere.

  1. Fresnel-Fizeau drag: Invisibility conditions for all inertial observers

    CERN Document Server

    Halimeh, Jad C

    2016-01-01

    It was recently shown [Halimeh \\emph{et al.} arXiv:1510.06114 (to appear in Phys. Rev. A)] that as a result of the Doppler effect, inherently dispersive single-frequency ideal free-space invisibility cloaks in relative motion to an observer can only cloak light whose frequency in the cloak frame coincides with the operational frequency of the cloak, although an infinite number of such rays exist for any cloak motion. In this article, we show analytically and through ray-tracing simulations that even though this relationship can be relaxed by simplifying the ideal invisibility cloak into a broadband amplitude cloak, Fresnel-Fizeau drag uncloaks the phase of light in the inertial frame of the cloak thereby compromising its amplitude cloaking in all other inertial frames. In other words, only an invisibility device that perfectly cloaks both the amplitude and the phase of light in its own inertial frame will also (perfectly) cloak this light in any other inertial frame. The same conclusion lends itself to invisi...

  2. Survey of Laser Markets Relevant to Inertial Fusion Energy Drivers, information for National Research Council

    Energy Technology Data Exchange (ETDEWEB)

    Bayramian, A J; Deri, R J; Erlandson, A C

    2011-02-24

    Development of a new technology for commercial application can be significantly accelerated by leveraging related technologies used in other markets. Synergies across multiple application domains attract research and development (R and D) talent - widening the innovation pipeline - and increases the market demand in common components and subsystems to provide performance improvements and cost reductions. For these reasons, driver development plans for inertial fusion energy (IFE) should consider the non-fusion technology base that can be lveraged for application to IFE. At this time, two laser driver technologies are being proposed for IFE: solid-state lasers (SSLs) and KrF gas (excimer) lasers. This document provides a brief survey of organizations actively engaged in these technologies. This is intended to facilitate comparison of the opportunities for leveraging the larger technical community for IFE laser driver development. They have included tables that summarize the commercial organizations selling solid-state and KrF lasers, and a brief summary of organizations actively engaged in R and D on these technologies.

  3. Can zonally symmetric inertial waves drive an oscillating mean flow?

    Science.gov (United States)

    Seelig, Torsten; Harlander, Uwe

    2016-04-01

    In the presentation [5] zonal mean flow excitation by inertial waves is studied in analogy to mean flow excitation by gravity waves [3] that plays an important role for the quasi-biennial oscillation in the equatorial atmosphere. In geophysical flows that are stratified and rotating, pure gravity and inertial waves correspond to the two limiting cases: gravity waves neglect rotation, inertial waves neglect stratification. The former are more relevant for fluids like the atmosphere, where stratification is dominant, the latter for the deep oceans or planet cores, where rotation dominates. In the present study a hierarchy of simple analytical and numerical models of zonally symmetric inertial wave-mean flow interactions is considered and the results are compared with data from a laboratory experiment [4]. The main findings can be summarised as follows: (i) when the waves are decoupled from the mean flow they just drive a retrograde (eastward) zonal mean flow, independent of the sign of the meridional phase speed; (ii) when coupling is present and the zonal mean flow is assumed to be steady, the waves can drive vertically alternating jets, but still, in contrast to the gravity wave case, the structure is independent of the sign of the meridional phase speed; (iii) when coupling is present and time-dependent zonal mean flows are considered the waves can drive vertically and temporarily oscillating mean flows. The comparison with laboratory data from a rotating annulus experiment shows a qualitative agreement. It appears that the experiment captures the basic elements of the inertial wave mean flow coupling. The results might be relevant to understand how the Equatorial Deep Jets can be maintained against dissipation [1, 2], a process currently discussed controversially. [1] Greatbatch, R., Brandt, P., Claus, M., Didwischus, S., Fu, Y.: On the width of the equatorial deep jets. J. Phys. Oceanogr. 42, 1729-1740 (2012) [2] Muench, J.E., Kunze, E.: Internal wave

  4. Recent Advances in Stellarator Optimization

    Science.gov (United States)

    Gates, David; Brown, T.; Breslau, J.; Landreman, M.; Lazerson, S. A.; Mynick, H.; Neilson, G. H.; Pomphrey, N.

    2016-10-01

    Computational optimization has revolutionized the field of stellarator design. To date, optimizations have focused primarily on optimization of neoclassical confinement and ideal MHD stability, although limited optimization of other parameters has also been performed. One criticism that has been levelled at this method of design is the complexity of the resultant field coils. Recently, a new coil optimization code, COILOPT + + , was written and included in the STELLOPT suite of codes. The advantage of this method is that it allows the addition of real space constraints on the locations of the coils. As an initial exercise, a constraint that the windings be vertical was placed on large major radius half of the non-planar coils. Further constraints were also imposed that guaranteed that sector blanket modules could be removed from between the coils, enabling a sector maintenance scheme. Results of this exercise will be presented. We have also explored possibilities for generating an experimental database that could check whether the reduction in turbulent transport that is predicted by GENE as a function of local shear would be consistent with experiments. To this end, a series of equilibria that can be made in the now latent QUASAR experiment have been identified. This work was supported by U.S. DoE Contract #DE-AC02-09CH11466.

  5. Stellar matter with pseudoscalar condensates

    Energy Technology Data Exchange (ETDEWEB)

    Andrianov, A.A. [Saint-Petersburg State University, St. Petersburg (Russian Federation); Universitat de Barcelona, Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos (ICCUB), Barcelona, Catalonia (Spain); Andrianov, V.A.; Kolevatov, S.S. [Saint-Petersburg State University, St. Petersburg (Russian Federation); Espriu, D. [Universitat de Barcelona, Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos (ICCUB), Barcelona, Catalonia (Spain)

    2016-03-15

    In this work we consider how the appearance of gradients of pseudoscalar condensates in dense systems may possibly influence the transport properties of photons in such a medium as well as other thermodynamic characteristics. We adopt the hypothesis that in regions where the pseudoscalar density gradient is large the properties of photons and fermions are governed by the usual lagrangian extended with a Chern-Simons interaction for photons and a constant axial field for fermions. We find that these new pieces in the lagrangian produce non-trivial reflection coefficients both for photons and fermions when entering or leaving a region where the pseudoscalar has a non-zero gradient. A varying pseudoscalar density may also lead to instability of some fermion and boson modes and modify some properties of the Fermi sea. We speculate that some of these modifications could influence the cooling rate of stellar matter (for instance in compact stars) and have other observable consequences. While quantitative results may depend on the precise astrophysical details most of the consequences are quite universal and consideration should be given to this possibility. (orig.)

  6. Stellar X-Ray Polarimetry

    Science.gov (United States)

    Swank, J.

    2011-01-01

    Most of the stellar end-state black holes, pulsars, and white dwarfs that are X-ray sources should have polarized X-ray fluxes. The degree will depend on the relative contributions of the unresolved structures. Fluxes from accretion disks and accretion disk corona may be polarized by scattering. Beams and jets may have contributions of polarized emission in strong magnetic fields. The Gravity and Extreme Magnetism Small Explorer (GEMS) will study the effects on polarization of strong gravity of black holes and strong magnetism of neutron stars. Some part of the flux from compact stars accreting from companion stars has been reflected from the companion, its wind, or accretion streams. Polarization of this component is a potential tool for studying the structure of the gas in these binary systems. Polarization due to scattering can also be present in X-ray emission from white dwarf binaries and binary normal stars such as RS CVn stars and colliding wind sources like Eta Car. Normal late type stars may have polarized flux from coronal flares. But X-ray polarization sensitivity is not at the level needed for single early type stars.

  7. Integrated optical waveguides and inertial focussing microfluidics in silica for microflow cytometry applications

    Science.gov (United States)

    Butement, Jonathan T.; Hunt, Hamish C.; Rowe, David J.; Sessions, Neil P.; Clark, Owain; Hua, Ping; Senthil Murugan, G.; Chad, John E.; Wilkinson, James S.

    2016-10-01

    A key challenge in the development of a microflow cytometry platform is the integration of the optical components with the fluidics as this requires compatible micro-optical and microfluidic technologies. In this work a microflow cytometry platform is presented comprising monolithically integrated waveguides and deep microfluidics in a rugged silica chip. Integrated waveguides are used to deliver excitation light to an etched microfluidic channel and also collect transmitted light. The fluidics are designed to employ inertial focussing, a particle positioning technique, to reduce signal variation by bringing the flowing particles onto the same plane as the excitation light beam. A fabrication process is described which exploits microelectronics mass production techniques including: sputtering, ICP etching and PECVD. Example devices were fabricated and the effectiveness of inertial focussing of 5.6 µm fluorescent beads was studied showing lateral and vertical confinement of flowing beads within the microfluidic channel. The fluorescence signals from flowing calibration beads were quantified demonstrating a CV of 26%. Finally the potential of this type of device for measuring the variation in optical transmission from input to output waveguide as beads flowed through the beam was evaluated.

  8. Gravity Matching Aided Inertial Navigation Technique Based on Marginal Robust Unscented Kalman Filter

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2015-01-01

    Full Text Available This paper is concerned with the topic of gravity matching aided inertial navigation technology using Kalman filter. The dynamic state space model for Kalman filter is constructed as follows: the error equation of the inertial navigation system is employed as the process equation while the local gravity model based on 9-point surface interpolation is employed as the observation equation. The unscented Kalman filter is employed to address the nonlinearity of the observation equation. The filter is refined in two ways as follows. The marginalization technique is employed to explore the conditionally linear substructure to reduce the computational load; specifically, the number of the needed sigma points is reduced from 15 to 5 after this technique is used. A robust technique based on Chi-square test is employed to make the filter insensitive to the uncertainties in the above constructed observation model. Numerical simulation is carried out, and the efficacy of the proposed method is validated by the simulation results.

  9. An ultra-low-voltage electronic implementation of inertial neuron model with nonmonotonous Liao's activation function.

    Science.gov (United States)

    Kant, Nasir Ali; Dar, Mohamad Rafiq; Khanday, Farooq Ahmad

    2015-01-01

    The output of every neuron in neural network is specified by the employed activation function (AF) and therefore forms the heart of neural networks. As far as the design of artificial neural networks (ANNs) is concerned, hardware approach is preferred over software one because it promises the full utilization of the application potential of ANNs. Therefore, besides some arithmetic blocks, designing AF in hardware is the most important for designing ANN. While attempting to design the AF in hardware, the designs should be compatible with the modern Very Large Scale Integration (VLSI) design techniques. In this regard, the implemented designs should: only be in Metal Oxide Semiconductor (MOS) technology in order to be compatible with the digital designs, provide electronic tunability feature, and be able to operate at ultra-low voltage. Companding is one of the promising circuit design techniques for achieving these goals. In this paper, 0.5 V design of Liao's AF using sinh-domain technique is introduced. Furthermore, the function is tested by implementing inertial neuron model. The performance of the AF and inertial neuron model have been evaluated through simulation results, using the PSPICE software with the MOS transistor models provided by the 0.18-μm Taiwan Semiconductor Manufacturer Complementary Metal Oxide Semiconductor (TSM CMOS) process.

  10. Adaptive Data Filtering of Inertial Sensors with Variable Bandwidth

    Science.gov (United States)

    Alam, Mushfiqul; Rohac, Jan

    2015-01-01

    MEMS (micro-electro-mechanical system)-based inertial sensors, i.e., accelerometers and angular rate sensors, are commonly used as a cost-effective solution for the purposes of navigation in a broad spectrum of terrestrial and aerospace applications. These tri-axial inertial sensors form an inertial measurement unit (IMU), which is a core unit of navigation systems. Even if MEMS sensors have an advantage in their size, cost, weight and power consumption, they suffer from bias instability, noisy output and insufficient resolution. Furthermore, the sensor's behavior can be significantly affected by strong vibration when it operates in harsh environments. All of these constitute conditions require treatment through data processing. As long as the navigation solution is primarily based on using only inertial data, this paper proposes a novel concept in adaptive data pre-processing by using a variable bandwidth filtering. This approach utilizes sinusoidal estimation to continuously adapt the filtering bandwidth of the accelerometer's data in order to reduce the effects of vibration and sensor noise before attitude estimation is processed. Low frequency vibration generally limits the conditions under which the accelerometers can be used to aid the attitude estimation process, which is primarily based on angular rate data and, thus, decreases its accuracy. In contrast, the proposed pre-processing technique enables using accelerometers as an aiding source by effective data smoothing, even when they are affected by low frequency vibration. Verification of the proposed concept is performed on simulation and real-flight data obtained on an ultra-light aircraft. The results of both types of experiments confirm the suitability of the concept for inertial data pre-processing. PMID:25648711

  11. Adaptive Data Filtering of Inertial Sensors with Variable Bandwidth

    Directory of Open Access Journals (Sweden)

    Mushfiqul Alam

    2015-02-01

    Full Text Available MEMS (micro-electro-mechanical system-based inertial sensors, i.e., accelerometers and angular rate sensors, are commonly used as a cost-effective solution for the purposes of navigation in a broad spectrum of terrestrial and aerospace applications. These tri-axial inertial sensors form an inertial measurement unit (IMU, which is a core unit of navigation systems. Even if MEMS sensors have an advantage in their size, cost, weight and power consumption, they suffer from bias instability, noisy output and insufficient resolution. Furthermore, the sensor’s behavior can be significantly affected by strong vibration when it operates in harsh environments. All of these constitute conditions require treatment through data processing. As long as the navigation solution is primarily based on using only inertial data, this paper proposes a novel concept in adaptive data pre-processing by using a variable bandwidth filtering. This approach utilizes sinusoidal estimation to continuously adapt the filtering bandwidth of the accelerometer’s data in order to reduce the effects of vibration and sensor noise before attitude estimation is processed. Low frequency vibration generally limits the conditions under which the accelerometers can be used to aid the attitude estimation process, which is primarily based on angular rate data and, thus, decreases its accuracy. In contrast, the proposed pre-processing technique enables using accelerometers as an aiding source by effective data smoothing, even when they are affected by low frequency vibration. Verification of the proposed concept is performed on simulation and real-flight data obtained on an ultra-light aircraft. The results of both types of experiments confirm the suitability of the concept for inertial data pre-processing.

  12. Fast Thermal Calibration of Low-Grade Inertial Sensors and Inertial Measurement Units

    Directory of Open Access Journals (Sweden)

    Yalong Ban

    2013-09-01

    Full Text Available The errors of low-cost inertial sensors, especially Micro-Electro Mechanical Systems (MEMS ones, are highly dependent on environmental conditions such as the temperature. Thus, there is a need for the development of accurate and reliable thermal compensation models to reduce the impact of such thermal drift of the sensors. Since the conventional thermal calibration methods are typically time-consuming and costly, an efficient thermal calibration method to investigate the thermal drift of a full set of gyroscope and accelerometer errors (i.e., biases, scale factor errors and non-orthogonalities over the entire temperature range in a few hours is proposed. The proposed method uses the idea of the Ramp method, which removes the time-consuming process of stabilizing the sensor temperature, and addresses its inherent problems with several improvements. We change the temperature linearly for a complete cycle and take a balanced strategy by making comprehensive use of the sensor measurements during both heating and cooling processes. Besides, an efficient 8-step rotate-and-static scheme is designed to further improve the calibration accuracy and efficiency. Real calibration tests showed that the proposed method is suitable for low-grade IMUs and for both lab and factory calibration due to its efficiency and sufficient accuracy.

  13. Fast thermal calibration of low-grade inertial sensors and inertial measurement units.

    Science.gov (United States)

    Niu, Xiaoji; Li, You; Zhang, Hongping; Wang, Qingjiang; Ban, Yalong

    2013-09-12

    The errors of low-cost inertial sensors, especially Micro-Electro Mechanical Systems (MEMS) ones, are highly dependent on environmental conditions such as the temperature. Thus, there is a need for the development of accurate and reliable thermal compensation models to reduce the impact of such thermal drift of the sensors. Since the conventional thermal calibration methods are typically time-consuming and costly, an efficient thermal calibration method to investigate the thermal drift of a full set of gyroscope and accelerometer errors (i.e., biases, scale factor errors and non-orthogonalities) over the entire temperature range in a few hours is proposed. The proposed method uses the idea of the Ramp method, which removes the time-consuming process of stabilizing the sensor temperature, and addresses its inherent problems with several improvements. We change the temperature linearly for a complete cycle and take a balanced strategy by making comprehensive use of the sensor measurements during both heating and cooling processes. Besides, an efficient 8-step rotate-and-static scheme is designed to further improve the calibration accuracy and efficiency. Real calibration tests showed that the proposed method is suitable for low-grade IMUs and for both lab and factory calibration due to its efficiency and sufficient accuracy.

  14. The Stagnation of Contemporary Stellar Astronomy

    CERN Document Server

    Škoda, Petr

    2011-01-01

    The stellar astronomy has always been considered the fundamental source of knowledge about the basic building blocks of the universe - the stars. It has proved correctness of many physical theories - like e.g. the idea of nuclear fusion in stellar cores, the exchange of mass in interacting binaries or models of stellar evolution towards white dwarfs or neutron stars. Despite its well acknowledged importance it seems to be loosing its interestingness for students, for telescope allocation committees at large observatories, as well as for granting agencies. In the domain of big telescopes it has been gradually overtaken by the extra-galactic research and cosmology, surviving however at smaller observatories and among most advanced amateur astronomers. We try to analyse the main obstacles lowering the efficiency of research in contemporary stellar astronomy. We will shortly tackle several problems induced by paradigmatic changes in handling the extraordinary amount of data provided by current instruments as well...

  15. Diagnostics for the National Compact Stellarator Experiment

    Energy Technology Data Exchange (ETDEWEB)

    B.C. Stratton; D. Johnson; R. Feder; E. Fredrickson; H. Neilson; H. Takahashi; M. Zarnstorf; M. Cole; P. Goranson; E. Lazarus; B. Nelson

    2003-09-16

    The status of planning of the National Compact Stellarator Experiment (NCSX) diagnostics is presented, with the emphasis on resolution of diagnostics access issues and on diagnostics required for the early phases of operation.

  16. CH in stellar atmospheres: an extensive linelist

    CERN Document Server

    Masseron, T; Van Eck, S; Colin, R; Daoutidis, I; Godefroid, M; Coheur, P F; Bernath, P; Jorissen, A; Christlieb, N

    2014-01-01

    The advent of high-resolution spectrographs and detailed stellar atmosphere modelling has strengthened the need for accurate molecular data. Carbon-enhanced metal-poor (CEMP) stars spectra are interesting objects with which to study transitions from the CH molecule. We combine programs for spectral analysis of molecules and stellar-radiative transfer codes to build an extensive CH linelist, including predissociation broadening as well as newly identified levels. We show examples of strong predissociation CH lines in CEMP stars, and we stress the important role played by the CH features in the Bond-Neff feature depressing the spectra of barium stars by as much as 0.2 magnitudes in the $\\lambda=$3000 -- 5500 \\AA\\ range. Because of the extreme thermodynamic conditions prevailing in stellar atmospheres (compared to the laboratory), molecular transitions with high energy levels can be observed. Stellar spectra can thus be used to constrain and improve molecular data.

  17. Stellar rotation effects in polarimetric microlensing

    CERN Document Server

    Sajadian, Sedighe

    2016-01-01

    It is well known that the polarization signal in microlensing events of hot stars is larger than that of main-sequence stars. Most hot stars rapidly rotate around their stellar axes. The stellar rotation makes ellipticity and gravity-darkening effects which break the spherical symmetry of the source shape and the circular symmetry of the source surface brightness respectively. Hence, it causes a net polarization signal for the source star. This polarization signal should be considered in polarimetry microlensing of fast rotating stars. For moderate rotating stars, lensing can magnify or even characterize small polarization signals due to the stellar rotation through polarimetry observations. The gravity-darkening effect due to a rotating source star makes asymmetric perturbations in polarimetry and photometry microlensing curves whose maximum happens when the lens trajectory crosses the projected position of the rotation pole on the sky plane. The stellar ellipticity makes a time shift (i) in the position of ...

  18. Estimating stellar mean density through seismic inversions

    CERN Document Server

    Reese, D R; Goupil, M J; Thompson, M J; Deheuvels, S

    2012-01-01

    Determining the mass of stars is crucial both to improving stellar evolution theory and to characterising exoplanetary systems. Asteroseismology offers a promising way to estimate stellar mean density. When combined with accurate radii determinations, such as is expected from GAIA, this yields accurate stellar masses. The main difficulty is finding the best way to extract the mean density from a set of observed frequencies. We seek to establish a new method for estimating stellar mean density, which combines the simplicity of a scaling law while providing the accuracy of an inversion technique. We provide a framework in which to construct and evaluate kernel-based linear inversions which yield directly the mean density of a star. We then describe three different inversion techniques (SOLA and two scaling laws) and apply them to the sun, several test cases and three stars. The SOLA approach and the scaling law based on the surface correcting technique described by Kjeldsen et al. (2008) yield comparable result...

  19. Bayesian isochrone fitting and stellar ages

    CERN Document Server

    Valls-Gabaud, D

    2016-01-01

    Stellar evolution theory has been extraordinarily successful at explaining the different phases under which stars form, evolve and die. While the strongest constraints have traditionally come from binary stars, the advent of asteroseismology is bringing unique measures in well-characterised stars. For stellar populations in general, however, only photometric measures are usually available, and the comparison with the predictions of stellar evolution theory have mostly been qualitative. For instance, the geometrical shapes of isochrones have been used to infer ages of coeval populations, but without any proper statistical basis. In this chapter we provide a pedagogical review on a Bayesian formalism to make quantitative inferences on the properties of single, binary and small ensembles of stars, including unresolved populations. As an example, we show how stellar evolution theory can be used in a rigorous way as a prior information to measure the ages of stars between the ZAMS and the Helium flash, and their u...

  20. F stars: A challenge to stellar evolution

    CERN Document Server

    Suchkov, A A

    2014-01-01

    Many main-sequence F and early G stars are too luminous for their effective temperature, surface gravity, and chemical composition. These {\\it overluminous stars} have two curious properties. First, their kinematics as a function of age from stellar evolution modeling (isochrone fitting) is very different from that of normal stars. Second, while X-ray luminosity of normal stars declines with age, the X-ray luminosity of overluminous F stars changes in the opposite direction, being on average higher for older stars. These properties imply that, in defiance of standard models of stellar evolution, F stars of a given mass and chemical composition can evolve very differently. Assuming that the models correctly describe normal stars, for overluminous F stars they predict too young age and the X-ray emission evolving in the direction opposite to the actually observed trend. This discrepancy between modeling results and observational data suggests that standard stellar evolution models and models of stellar activity...

  1. Convection in stellar envelopes a changing paradigm

    CERN Document Server

    Spruit, H C

    1996-01-01

    Progress in the theory of stellar convection over the past decade is reviewed. The similarities and differences between convection in stellar envelopes and laboratory convection at high Rayleigh numbers are discussed. Direct numerical simulation of the solar surface layers, with no other input than atomic physics, the equations of hydrodynamics and radiative transfer is now capable of reproducing the observed heat flux, convection velocities, granulation patterns and line profiles with remarkably accuracy. These results show that convection in stellar envelopes is an essentially non-local process, being driven by cooling at the surface. This differs distinctly from the traditional view of stellar convection in terms of local concepts such as cascades of eddies in a mean superadiabatic gradient. The consequences this has for our physical picture of processes in the convective envelope are illustrated with the problems of sunspot heat flux blocking, the eruption of magnetic flux from the base of the convection ...

  2. Chemical element transport in stellar evolution models

    Science.gov (United States)

    Cassisi, Santi

    2017-01-01

    Stellar evolution computations provide the foundation of several methods applied to study the evolutionary properties of stars and stellar populations, both Galactic and extragalactic. The accuracy of the results obtained with these techniques is linked to the accuracy of the stellar models, and in this context the correct treatment of the transport of chemical elements is crucial. Unfortunately, in many respects calculations of the evolution of the chemical abundance profiles in stars are still affected by sometimes sizable uncertainties. Here, we review the various mechanisms of element transport included in the current generation of stellar evolution calculations, how they are implemented, the free parameters and uncertainties involved, the impact on the models and the observational constraints.

  3. The K2-TESS Stellar Properties Catalog

    CERN Document Server

    Stassun, Keivan G; Paegert, Martin; De Lee, Nathan; Sanchis-Ojeda, Roberto

    2014-01-01

    We introduce a catalog of stellar properties for stars observed by the Kepler follow-on mission, K2. We base the catalog on a cross-match between the K2 Campaign target lists and the current working version of the NASA TESS target catalog. The resulting K2-TESS Stellar Properties Catalog includes value-added information from the TESS Target Catalog, including stellar colors, proper motions, and an estimated luminosity class (dwarf/subgiant versus giant) for each star based on a reduced-proper-motion criterion. Also included is the Guest Observer program identification number(s) associated with each K2 target. The K2-TESS Stellar Properties Catalog is available to the community as a freely accessible data portal on the Filtergraph system at: http://filtergraph.vanderbilt.edu/tess_k2campaigns .

  4. Collisionless microinstabilities in stellarators II - numerical simulations

    CERN Document Server

    Proll, Josefine Henriette Elise; Helander, Per

    2013-01-01

    Microinstabilities exhibit a rich variety of behavior in stellarators due to the many degrees of freedom in the magnetic geometry. It has recently been found that certain stellarators (quasi-isodynamic ones with maximum-$J$ geometry) are partly resilient to trapped-particle instabilities, because fast-bouncing particles tend to extract energy from these modes near marginal stability. In reality, stellarators are never perfectly quasi-isodynamic, and the question thus arises whether they still benefit from enhanced stability. Here the stability properties of Wendelstein 7-X and a more quasi-isodynamic configuration, QIPC, are investigated numerically and compared with the National Compact Stellarator Experiment (NCSX) and the DIII-D tokamak. In gyrokinetic simulations, performed with the gyrokinetic code GENE in the electrostatic and collisionless approximation, ion-temperature-gradient modes, trapped-electron modes and mixed-type instabilities are studied. Wendelstein 7-X and QIPC exhibit significantly reduce...

  5. Inertial motion capture system for biomechanical analysis in pressure suits

    Science.gov (United States)

    Di Capua, Massimiliano

    A non-invasive system has been developed at the University of Maryland Space System Laboratory with the goal of providing a new capability for quantifying the motion of the human inside a space suit. Based on an array of six microprocessors and eighteen microelectromechanical (MEMS) inertial measurement units (IMUs), the Body Pose Measurement System (BPMS) allows the monitoring of the kinematics of the suit occupant in an unobtrusive, self-contained, lightweight and compact fashion, without requiring any external equipment such as those necessary with modern optical motion capture systems. BPMS measures and stores the accelerations, angular rates and magnetic fields acting upon each IMU, which are mounted on the head, torso, and each segment of each limb. In order to convert the raw data into a more useful form, such as a set of body segment angles quantifying pose and motion, a series of geometrical models and a non-linear complimentary filter were implemented. The first portion of this works focuses on assessing system performance, which was measured by comparing the BPMS filtered data against rigid body angles measured through an external VICON optical motion capture system. This type of system is the industry standard, and is used here for independent measurement of body pose angles. By comparing the two sets of data, performance metrics such as BPMS system operational conditions, accuracy, and drift were evaluated and correlated against VICON data. After the system and models were verified and their capabilities and limitations assessed, a series of pressure suit evaluations were conducted. Three different pressure suits were used to identify the relationship between usable range of motion and internal suit pressure. In addition to addressing range of motion, a series of exploration tasks were also performed, recorded, and analysed in order to identify different motion patterns and trajectories as suit pressure is increased and overall suit mobility is reduced

  6. Mean flow generation mechanism by inertial waves and normal modes

    Science.gov (United States)

    Will, Andreas; Ghasemi, Abouzar

    2016-04-01

    The mean flow generation mechanism by nonlinearity of the inertial normal modes and inertial wave beams in a rotating annular cavity with longitudinally librating walls in stable regime is discussed. Inertial normal modes (standing waves) are excited when libration frequency matches eigenfrequencies of the system. Inertial wave beams are produced by Ekman pumping and suction in a rotating cylinder and form periodic orbits or periodic ray trajectories at selected frequencies. Inertial wave beams emerge as concentrated shear layers in a librating annular cavity, while normal modes appear as global recirculation cells. Both (inertial wave beam and mode) are helical and thus intrinsically non-linear flow structures. No second mode or wave is necessary for non-linearity. We considered the low order normal modes (1,1), (2,1) and (2,2) which are expected to be excited in the planetary objects and investigate the mean flow generation mechanism using two independent solutions: 1) analytical solution (Borcia 2012) and 2) the wave component of the flow (ω0 component) obtained from the direct numerical simulation (DNS). It is well known that a retrograde bulk mean flow is generated by the Ekman boundary layer and E1/4-Stewartson layer close to the outer cylinder side wall due to libration. At and around the normal mode resonant frequencies we found additionally a prograde azimuthal mean flow (Inertial Normal Mode Mean Flow: INMMF) in the bulk of the fluid. The fluid in the bulk is in geostrophic balance in the absence of the inertial normal modes. However, when INMMF is excited, we found that the geostrophic balance does not hold in the region occupied by INMMF. We hypothesize that INMMF is generated by the nonlinearity of the normal modes or by second order effects. Expanding the velocity {V}(u_r,u_θ,u_z) and pressure (p) in a power series in ɛ (libration amplitude), the Navier-Stokes equations are segregated into the linear and nonlinear parts at orders ɛ1 and ɛ^2

  7. Inertial Gait Phase Detection for control of a drop foot stimulator: Inertial sensing for gait phase detection

    NARCIS (Netherlands)

    Kotiadis, D; Hermens, H.J.; Veltink, P.H.

    2010-01-01

    An Inertial Gait Phase Detection system was developed to replace heel switches and footswitches currently being used for the triggering of drop foot stimulators. A series of four algorithms utilising accelerometers and gyroscopes individually and in combination were tested and initial results are sh

  8. The Zeeman effect in stellar spectra

    Science.gov (United States)

    Romanyuk, I. I.

    A short biography of Pieter Zeeman is presented. The main formulae for the normal, anomalous, quadratic Zeeman effects and Paschen-Back effect are given. Instrumentation for Zeeman effect measurements in stellar spectra is described, the most important scientific achievements in magnetic stars investigations with the world's largest telescopes for 50 years are demonstrated. The devices for magnetic measurements made at SAO and the main results of stellar magnetic observations obtained with the 6 m telescope are described in detail.

  9. Does the stellar distribution flare? A comparison of stellar scale heights with LAB H I data

    Energy Technology Data Exchange (ETDEWEB)

    Kalberla, P. M. W.; Kerp, J.; Dedes, L. [Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn (Germany); Haud, U., E-mail: pkalberla@astro.uni-bonn.de [Tartu Observatory, 61602 Tõravere (Estonia)

    2014-10-10

    The question of whether the stellar populations in the Milky Way take part in the flaring of scale heights as observed for the H I gas is a matter of debate. Standard mass models for the Milky Way assume a constant scale height for each of the different stellar distributions. However, there is mounting evidence that at least some of the stellar distributions reach, at large galactocentric distances, high altitudes, which are incompatible with a constant scale height. We discuss recent observational evidence for stellar flaring and compare it with H I data from the Leiden/Argentine/Bonn survey. Within the systemic and statistical uncertainties we find a good agreement between both.

  10. Does the Stellar Distribution Flare? A Comparison of Stellar Scale Heights with LAB H I Data

    Science.gov (United States)

    Kalberla, P. M. W.; Kerp, J.; Dedes, L.; Haud, U.

    2014-10-01

    The question of whether the stellar populations in the Milky Way take part in the flaring of scale heights as observed for the H I gas is a matter of debate. Standard mass models for the Milky Way assume a constant scale height for each of the different stellar distributions. However, there is mounting evidence that at least some of the stellar distributions reach, at large galactocentric distances, high altitudes, which are incompatible with a constant scale height. We discuss recent observational evidence for stellar flaring and compare it with H I data from the Leiden/Argentine/Bonn survey. Within the systemic and statistical uncertainties we find a good agreement between both.

  11. Does the stellar distribution flare? A comparison of stellar scale heights with LAB HI data

    CERN Document Server

    Kalberla, P M W; Dedes, L; Haud, U

    2014-01-01

    The question, whether the stellar populations in the Milky Way take part in flaring of the scale heights as observed for the HI gas is a matter of debate. Standard mass models for the Milky Way assume a constant scale height for each of the different stellar distributions. However, there is mounting evidence that at least some of the stellar distributions reach at large galactocentric distances high altitudes that are incompatible with a constant scale height. We discuss recent observational evidence for stellar flaring and compare it with HI data from the Leiden/Argentine/Bonn (LAB) survey. Within the systemic and statistical uncertainties we find a good agreement between both.

  12. Featured Image: A Looping Stellar Stream

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    This negative image of NGC 5907 (originally published inMartinez-Delgadoet al. 2008; click for the full view!) reveals the faint stellar stream that encircles the galaxy, forming loops around it a fossil of a recent merger. Mergers between galaxies come in several different flavors: major mergers, in which the merging galaxies are within a 1:5 ratio in stellar mass; satellite cannibalism, in which a large galaxy destroys a small satellite less than a 50th of its size; and the in-between case of minor mergers, in which the merging galaxieshave stellar mass ratios between 1:5 and 1:50. These minor mergers are thought to be relatively common, and they can have a significant effect on the dynamics and structure of the primary galaxy. A team of scientists led by Seppo Laine (Spitzer Science Center Caltech) has recently analyzed the metallicity and age of the stellar population in the stream around NGC 5907. By fitting these observations with a stellar population synthesis model, they conclude that this stream is an example of a massive minor merger, with a stellar mass ratio of at least 1:8. For more information, check out the paper below!CitationSeppo Laine et al 2016 AJ 152 72. doi:10.3847/0004-6256/152/3/72

  13. Ubiquitous time variability of integrated stellar populations.

    Science.gov (United States)

    Conroy, Charlie; van Dokkum, Pieter G; Choi, Jieun

    2015-11-26

    Long-period variable stars arise in the final stages of the asymptotic giant branch phase of stellar evolution. They have periods of up to about 1,000 days and amplitudes that can exceed a factor of three in the I-band flux. These stars pulsate predominantly in their fundamental mode, which is a function of mass and radius, and so the pulsation periods are sensitive to the age of the underlying stellar population. The overall number of long-period variables in a population is directly related to their lifetimes, which is difficult to predict from first principles because of uncertainties associated with stellar mass-loss and convective mixing. The time variability of these stars has not previously been taken into account when modelling the spectral energy distributions of galaxies. Here we construct time-dependent stellar population models that include the effects of long-period variable stars, and report the ubiquitous detection of this expected 'pixel shimmer' in the massive metal-rich galaxy M87. The pixel light curves display a variety of behaviours. The observed variation of 0.1 to 1 per cent is very well matched to the predictions of our models. The data provide a strong constraint on the properties of variable stars in an old and metal-rich stellar population, and we infer that the lifetime of long-period variables in M87 is shorter by approximately 30 per cent compared to predictions from the latest stellar evolution models.

  14. The distribution of stellar populations within galaxies

    Science.gov (United States)

    Novais, P. M.; Sodré, L., Jr.

    2014-10-01

    The study of stellar populations in galaxies is particularly interesting, since they are a fossil record of several physical processes associated with the formation and evolution of galaxies. In this work we present the first results of our approach to study the spatial distribution of stellar populations inside galaxies. We are using ugriz magnitudes and principal component analysis (PCA) to obtain pixel-by-pixel proxies of the stellar populations and their distributions inside each galaxy. The distribution of these populations are then investigated with a variety of statistical tools, including Gini Indices and the Euler-Poincaré characteristic. Our approach aims to be a step forward with respect to the conventional profile fitting, allowing to obtain quantitative estimates on how the different stellar populations are distributed within a galaxy, bringing hints on how galaxies grow and evolve. The pixel-by-pixel analysis of a small sample of 15 galaxies of different types show that the stellar populations tend to evolve from inside to out in spiral and late spiral galaxies, while elliptical galaxies seem to have young stellar populations in the center. This first results show that this approach is effective and will be explored and improve in future works.

  15. Automated Driftmeter Fused with Inertial Navigation

    Science.gov (United States)

    2014-03-27

    urban canyons . GPS is also vulnerable to attack or disruption, such as jamming or spoofing [16]. 1.2 Motivation Advancements in computer technology...deg/hr 1800 1.0 Gyro bias time constant hr 2* 2* Angular random walk deg/ √ hr 2.23 0.3 Gyro scalefactor sigma PPM 10000 150 Accel bias sigma m/s2...0.196 0.0098 Accel bias time constant hr 2* 2* Velocity random walk m/s / √ hr 0.261 0.57* Accel scalefactor sigma PPM 10000 300 An extended Kalman

  16. Error and Performance Analysis of MEMS-based Inertial Sensors with a Low-cost GPS Receiver

    Directory of Open Access Journals (Sweden)

    Yang Gao

    2008-03-01

    Full Text Available Global Navigation Satellite Systems (GNSS, such as the Global Positioning System (GPS, have been widely utilized and their applications are becoming popular, not only in military or commercial applications, but also for everyday life. Although GPS measurements are the essential information for currently developed land vehicle navigation systems (LVNS, GPS signals are often unavailable or unreliable due to signal blockages under certain environments such as urban canyons. This situation must be compensated in order to provide continuous navigation solutions. To overcome the problems of unavailability and unreliability using GPS and to be cost and size effective as well, Micro Electro Mechanical Systems (MEMS based inertial sensor technology has been pushing for the development of low-cost integrated navigation systems for land vehicle navigation and guidance applications. This paper will analyze the characterization of MEMS based inertial sensors and the performance of an integrated system prototype of MEMS based inertial sensors, a low-cost GPS receiver and a digital compass. The influence of the stochastic variation of sensors will be assessed and modeled by two different methods, namely Gauss-Markov (GM and AutoRegressive (AR models, with GPS signal blockage of different lengths. Numerical results from kinematic testing have been used to assess the performance of different modeling schemes.

  17. Pedestrian Tracking Solution Combining an Impulse Radio Handset Transmitter with an Ankle-Mounted Inertial Measurement Unit

    Directory of Open Access Journals (Sweden)

    Joe Youssef

    2012-01-01

    Full Text Available We address the indoor tracking problem by combining an Impulse Radio-Ultra-Wideband handset with an ankle-mounted Inertial Measurement Unit embedding an accelerometer and a gyroscope. The latter unit makes possible the detection of the stance phases to overcome velocity drifts. Regarding radiolocation, a time-of-arrival estimator adapted to energy-based receivers is applied to mitigate the effects of dense multipath profiles. A novel quality factor associated with this estimator is also provided as a function of the received signal-to-noise ratio, enabling us to identify outliers corresponding to obstructed radio links and to scale the covariance matrix of radiolocation measurements. Finally, both radio and inertial subsystems are loosely-coupled into one single navigation solution relying on a specific extended Kalman filter. In the proposed fusion strategy, processed inertial data control the filter state prediction whereas Combined Time Differences Of Arrival are formed as input observations. These combinations offer low computational complexity as well as a unique filter structure over time, even after removing outliers. Experimental results obtained in a representatively harsh indoor environment emphasize the complementarity of the two technologies and the relevance of the chosen fusion method while operating with low-cost, noncollocated, asynchronous, and heterogeneous sensors.

  18. Determination of the position angle of stellar spin axes

    CERN Document Server

    Lesage, Anna-Lea

    2014-01-01

    Measuring the stellar position angle provides valuable information on binary stellar formation or stellar spin axis evolution. We aim to develop a method for determining the absolute stellar position angle using spectro-astrometric analysis of high resolution long-slit spectra. The method has been designed in particular for slowly rotating stars. We investigate its applicability to existing dispersive long-slit spectrographs, identified here by their plate scale, and the size of the resulting stellar sample. The stellar rotation induces a tilt in the stellar lines whose angle depends on the stellar position angle and the orientation of the slit. We developed a rotation model to calculate and reproduce the effects of stellar rotation on unreduced high resolution stellar spectra. Then we retrieved the tilt amplitude using a spectro-astrometric extraction of the position of the photocentre of the spectrum. Finally we present two methods for analysing the position spectrum using either direct measurement of the t...

  19. On the local stellar populations

    Science.gov (United States)

    Fuhrmann, Klaus; Chini, Rolf; Kaderhandt, Lena; Chen, Zhiwei

    2017-01-01

    We present a study of the local stellar populations from a volume-complete all-sky survey of the about 500 bright stars with distances less than 25 pc and down to main-sequence effective temperatures Teff ≥ 5300 K. The sample is dominated by a 93 per cent fraction of Population I stars, only 22 sources (5 per cent) are Population II stars, and 9 sources (2 per cent) are intermediate-disc stars. No source belongs to the halo. By following the mass of the stars instead of their light, the resulting subset of 136 long-lived stars distributes as 22 (16.2 per cent):6 (4.4 per cent):108 (79.4 per cent) for the Population II:intermediate disc:Population I, respectively. Along with the much larger scaleheight reached by Population II, this unbiased census of long-lived stars provides plain evidence for a starburst epoch in the early Milky Way, with the formation of a massive, rotationally supported, and dark Population II. The same conclusion arises from the substantial early chemical enrichment levels, exemplified here by the elements magnesium and iron, as it arises also from the local Population II white dwarfs. The kinematics, metallicity distribution functions, star formation rates, age-metallicity relations, the inventory of young stars, and the occurrence of blue straggler stars are discussed. A potentially new aspect of the survey is the possibility for substructure among the local Population II stars that may further subdivide into metal-poor and metal-rich sources.

  20. IUVS/MAVEN Stellar Occultations

    Science.gov (United States)

    Gröller, Hannes; Yelle, Roger; Montmessin, Franck; Lacombe, Gaetan; Schneider, Nicholas M.; Deighan, Justin; Jain, Sonal; Nakagawa, Hiromu; Jakosky, Bruce

    2016-10-01

    We present the latest results from stellar occultations observed with the Imaging Ultraviolet Spectrograph (IUVS) instrument on board of Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. So far 9 campaigns have been executed on average every two months since MAVEN began orbiting Mars. Approximately 50 occultations are recorded in each campaign. The IUVS instrument observes in two spectral regions, the far- and mid-UV. The FUV channel covers wavelengths from 110 to 190 nm and the MUV channel from 170 to 350 nm. By combining those two channels we cover the whole altitude range starting from around 30 km to 150 km. We present the geometric dependent CO2, O2, and O3 number densities from these occultations. The derived O2 mixing ratio varies between 1.5 × 10-3 and 5 × 10-3. In some of the MUV occultations we also can see aerosol extinction. In addition we present temperatures derived from the CO2 densities assuming hydrostatic equilibrium. We retrieved mean temperatures of around 180 K at lower altitudes, which decreasing with altitudes down to a mean of around 130 K at higher altitudes. We see a constantly cold layer with temperatures of 105 – 120 K at a pressure level at roughly 7 × 10-6 Pa, equivalent to an altitude of around 140 km. We also discuss possible wave structures with amplitudes between 5 and 15 K and wavelengths between 10 and 15 km in the obtained temperature profiles. The temperature profiles, retrieved with the IUVS instrument, are mostly in agreement with predicted values from the Mars Climate Database model, except where we see the cold layer around 140 km.

  1. Inertial and GPS data integration for positioning and tracking of GPR

    Science.gov (United States)

    Chicarella, Simone; D'Alvano, Alessandro; Ferrara, Vincenzo; Frezza, Fabrizio; Pajewski, Lara

    2015-04-01

    approach to data processing and visualization,' Proceedings of 15th IEEE International Conference on Ground Penetrating Radar - GPR 2014, Brussels, Belgium, June 30 - July 4, 2014, pp. 913-918. [2] S. Urbini, L. Vittuari, and S. Gandolfi, 'GPR and GPS data integration: examples of application in Antarctica,' Annali di Geofisica, Vol. 44, No. 4, August 2001, pp. 687-702. [3] V. Prokhorenko, V. Ivashchuk, S. Korsun, and O. Dykovska, 'An Inertial Measurement Unit Application for a GPR Tracking and Positioning,' Proceedings of the 12th International Conference on Ground Penetrating Radar, June 15-19, 2008, Birmingham, UK, pp. 19-24. [4] M. Pasternak, W. Miluski, W. Czarnecki, and J. Pietrasinski, 'An optoelectronic-inertial system for handheld GPR positioning,' Proceedings of the 15th IEEE International Radar Symposium (IRS), Gdansk, Poland, June 16-18, 2014, pp. 1-4. [5] L. Crocco and V. Ferrara, 'A Review on Ground Penetrating Radar Technology for the Detection of Buried or Trapped Victims,' Proceedings of the IEEE 2nd International Workshop on Collaborations in Emergency Response and Disaster Management (ERDM 2014) as part of 2014 International Conference on Collaboration Technologies and Systems (CTS 2014) - Minneapolis (Minnesota, USA), May 19-23, 2014, pp. 535-540.

  2. Inertial Sensor Characterization for Inertial Navigation and Human Motion Tracking Applications

    Science.gov (United States)

    2012-06-01

    Science and Technology. New York: McGraw-Hill, 2006, Credo Reference, [Online]. Available: http://www.credoreference.com/entry/conscitech...Hill Concise Encyclopedia of Science and Technology. New York: McGraw-Hill, 2006, Credo Reference, [Online]. Available: http://www.credoreference.com...mean-square.” McGraw-Hill Concise Encyclopedia of Science and Technology, New York: McGraw-Hill, 2006. Credo Reference, [Online]. Available: http

  3. Interplanetary space transport using inertial fusion propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Orth, C.D.

    1998-04-20

    In this paper, we indicate how the great advantages that ICF offers for interplanetary propulsion can be accomplished with the VISTA spacecraft concept. The performance of VISTA is expected to surpass that from other realistic technologies for Mars missions if the energy gain achievable for ICF targets is above several hundred. Based on the good performance expected from the U. S. National Ignition Facility (NIF), the requirements for VISTA should be well within the realm of possibility if creative target concepts such as the fast ignitor can be developed. We also indicate that a 6000-ton VISTA can visit any planet in the solar system and return to Earth in about 7 years or less without any significant physiological hazards to astronauts. In concept, VISTA provides such short-duration missions, especially to Mars, that the hazards from cosmic radiation and zero gravity can be reduced to insignificant levels. VISTA therefore represents a significant step forward for space-propulsion concepts.

  4. Inertial quantum sensors using light and matter

    CERN Document Server

    Barrett, B; Bouyer, P

    2016-01-01

    The past few decades have seen dramatic progress in our ability to manipulate and coherently control matter-waves. Although the duality between particles and waves has been well tested since de Broglie introduced the matter-wave analog of the optical wavelength in 1924, manipulating atoms with a level of coherence that enables one to use these properties for precision measurements has only become possible with our ability to produce atomic samples exhibiting temperatures of only a few millionths of a degree above absolute zero. Since the initial experiments a few decades ago, the field of atom optics has developed in many ways, with both fundamental and applied significance. The exquisite control of matter waves offers the prospect of a new generation of force sensors exhibiting unprecedented sensitivity and accuracy, for applications from navigation and geophysics to tests of general relativity. Thanks to the latest developments in this field, the first commercial products using this quantum technology are n...

  5. Inertial Confinement Fusion Quarterly Report: April--June 1993. Volume 3, Number 3

    Energy Technology Data Exchange (ETDEWEB)

    MacGowan, B.J.; Kotowski, M.; Schleich, D. [eds.

    1993-11-01

    This issue of the ICF Quarterly contains six articles describing recent advances in Lawrence Livermore National Laboratory`s inertial confinement fusion (ICF) program. The current emphasis of the ICF program is in support of DOE`s National Ignition Facility (NIF) initiative for demonstrating ignition and gain with a 1-2 MJ glass laser. The articles describe recent Nova experiments and investigations tailored towards enhancing understanding of the key physics and technological issues for the NIF. Titles of the articles are: development of large-aperture KDP crystals; inner-shell photo-ionized X-ray lasers; X-ray radiographic measurements of radiation-driven shock and interface motion in solid density materials; the role of nodule defects in laser-induced damage of multilayer optical coatings; techniques for Mbar to near-Gbar equation-of-state measurements with the Nova laser; parametric instabilities and laser-beam smoothing.

  6. A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

    CERN Document Server

    Kuang, Longyu; Jing, Longfei; Lin, Zhiwei; Zhang, Lu; Li, Lilin; Ding, Yongkun; Jiang, Shaoen; Liu, Jie; Zheng, Jian

    2016-01-01

    A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named as three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is made of three cylindrical hohlraums orthogonally jointed. Laser beams are injected through every entrance hole with the same incident angle of 55{\\deg}. The view-factor simulation result shows that the time-varying drive asymmetry of TACH is no more than 1.0% in the whole drive pulse period without any supplementary technology such as beam phasing etc. Its coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, the proposed hohlraum provides a competitive candidate for ignition hohlraum.

  7. In-flight thermal experiments for LISA Pathfinder: Simulating temperature noise at the Inertial Sensors

    Science.gov (United States)

    Gibert, F.; Nofrarias, M.; Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E.; Freschi, M.; Gallegos, J.; García Marirrodriga, C.; Gerndt, R.; Gesa, Ll; Giardini, D.; Giusteri, R.; Grimani, C.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C.; Lloro, I.; Maarschalkerweerd, R.; Madden, S.; Maghami, P.; Mance, D.; Martín, V.; Martin-Porqueras, F.; Mateos, I.; McNamara, P.; Mendes, J.; Mendes, L.; Moroni, A.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J.; Trenkel, C.; Tu, H. B.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.

    2015-05-01

    Thermal Diagnostics experiments to be carried out on board LISA Pathfinder (LPF) will yield a detailed characterisation of how temperature fluctuations affect the LTP (LISA Technology Package) instrument performance, a crucial information for future space based gravitational wave detectors as the proposed eLISA. Amongst them, the study of temperature gradient fluctuations around the test masses of the Inertial Sensors will provide as well information regarding the contribution of the Brownian noise, which is expected to limit the LTP sensitivity at frequencies close to 1 mHz during some LTP experiments. In this paper we report on how these kind of Thermal Diagnostics experiments were simulated in the last LPF Simulation Campaign (November, 2013) involving all the LPF Data Analysis team and using an end-to-end simulator of the whole spacecraft. Such simulation campaign was conducted under the framework of the preparation for LPF operations.

  8. Research on laser Doppler velocimeter for vehicle self-contained inertial navigation system

    Science.gov (United States)

    Jian, Zhou; Xingwu, Long

    2010-04-01

    An idea of using laser Doppler velocimeter (LDV) to measure the velocity for the vehicle inertial navigation system was put forward. The principle of measuring its own velocity with laser Doppler technique was elaborated and reference-beam LDV was designed. Then Doppler signal was processed by tracking filter, frequency spectrum refinement and frequency spectrum correction algorithm. The result of theory and experiment showed that the reference-beam LDV solved the problem that dual-beam LDV cannot be used for measuring when the system was out of focus. Doppler signal was tracked so that signal-to-noise ratio was improved, and the accuracy of the system was enhanced by the technology of frequency spectrum refinement and correction. The measurement mean error was less than 1.5% in velocity range of 0-30 m/s.

  9. A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

    Science.gov (United States)

    Kuang, Longyu; Li, Hang; Jing, Longfei; Lin, Zhiwei; Zhang, Lu; Li, Liling; Ding, Yongkun; Jiang, Shaoen; Liu, Jie; Zheng, Jian

    2016-01-01

    A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is orthogonally jointed of three cylindrical hohlraums. Laser beams are injected through every entrance hole with the same incident angle of 55°. A view-factor simulation result shows that the time-varying drive asymmetry of TACH is less than 1.0% in the whole drive pulse period without any supplementary technology. Coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to that of typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, TACH combines most advantages of various hohlraums and has little predictable risk, providing an important competitive candidate for ignition hohlraum. PMID:27703250

  10. LIDAR-Aided Inertial Navigation with Extended Kalman Filtering for Pinpoint Landing

    Science.gov (United States)

    Busnardo, David M.; Aitken, Matthew L.; Tolson, Robert H.; Pierrottet, Diego; Amzajerdian, Farzin

    2011-01-01

    In support of NASA s Autonomous Landing and Hazard Avoidance Technology (ALHAT) project, an extended Kalman filter routine has been developed for estimating the position, velocity, and attitude of a spacecraft during the landing phase of a planetary mission. The proposed filter combines measurements of acceleration and angular velocity from an inertial measurement unit (IMU) with range and Doppler velocity observations from an onboard light detection and ranging (LIDAR) system. These high-precision LIDAR measurements of distance to the ground and approach velocity will enable both robotic and manned vehicles to land safely and precisely at scientifically interesting sites. The filter has been extensively tested using a lunar landing simulation and shown to improve navigation over flat surfaces or rough terrain. Experimental results from a helicopter flight test performed at NASA Dryden in August 2008 demonstrate that LIDAR can be employed to significantly improve navigation based exclusively on IMU integration.

  11. A Novel AHRS Inertial Sensor-Based Algorithm for Wheelchair Propulsion Performance Analysis

    Directory of Open Access Journals (Sweden)

    Jonathan Bruce Shepherd

    2016-08-01

    Full Text Available With the increasing rise of professionalism in sport, athletes, teams, and coaches are looking to technology to monitor performance in both games and training in order to find a competitive advantage. The use of inertial sensors has been proposed as a cost effective and adaptable measurement device for monitoring wheelchair kinematics; however, the outcomes are dependent on the reliability of the processing algorithms. Though there are a variety of algorithms that have been proposed to monitor wheelchair propulsion in court sports, they all have limitations. Through experimental testing, we have shown the Attitude and Heading Reference System (AHRS-based algorithm to be a suitable and reliable candidate algorithm for estimating velocity, distance, and approximating trajectory. The proposed algorithm is computationally inexpensive, agnostic of wheel camber, not sensitive to sensor placement, and can be embedded for real-time implementations. The research is conducted under Griffith University Ethics (GU Ref No: 2016/294.

  12. Z-inertial fusion energy: power plant final report FY 2006.

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark (University of Wisconsin, Madison, WI); Kulcinski, Gerald (University of Wisconsin, Madison, WI); Zhao, Haihua (University of California, Berkeley, CA); Cipiti, Benjamin B.; Olson, Craig Lee; Sierra, Dannelle P.; Meier, Wayne (Lawrence Livermore National Laboratories); McConnell, Paul E.; Ghiaasiaan, M. (Georgia Institute of Technology, Atlanta, GA); Kern, Brian (Georgia Institute of Technology, Atlanta, GA); Tajima, Yu (University of California, Los Angeles, CA); Campen, Chistopher (University of California, Berkeley, CA); Sketchley, Tomas (University of California, Los Angeles, CA); Moir, R (Lawrence Livermore National Laboratories); Bardet, Philippe M. (University of California, Berkeley, CA); Durbin, Samuel; Morrow, Charles W.; Vigil, Virginia L (University of Wisconsin, Madison, WI); Modesto-Beato, Marcos A.; Franklin, James Kenneth (University of California, Berkeley, CA); Smith, James Dean; Ying, Alice (University of California, Los Angeles, CA); Cook, Jason T.; Schmitz, Lothar (University of California, Los Angeles, CA); Abdel-Khalik, S. (Georgia Institute of Technology, Atlanta, GA); Farnum, Cathy Ottinger; Abdou, Mohamed A. (University of California, Los Angeles, CA); Bonazza, Riccardo (University of Wisconsin, Madison, WI); Rodriguez, Salvador B.; Sridharan, Kumar (University of Wisconsin, Madison, WI); Rochau, Gary Eugene; Gudmundson, Jesse (University of Wisconsin, Madison, WI); Peterson, Per F. (University of California, Berkeley, CA); Marriott, Ed (University of Wisconsin, Madison, WI); Oakley, Jason (University of Wisconsin, Madison, WI)

    2006-10-01

    This report summarizes the work conducted for the Z-inertial fusion energy (Z-IFE) late start Laboratory Directed Research Project. A major area of focus was on creating a roadmap to a z-pinch driven fusion power plant. The roadmap ties ZIFE into the Global Nuclear Energy Partnership (GNEP) initiative through the use of high energy fusion neutrons to burn the actinides of spent fuel waste. Transmutation presents a near term use for Z-IFE technology and will aid in paving the path to fusion energy. The work this year continued to develop the science and engineering needed to support the Z-IFE roadmap. This included plant system and driver cost estimates, recyclable transmission line studies, flibe characterization, reaction chamber design, and shock mitigation techniques.

  13. Advanced stellar compass deep space navigation, ground testing results

    DEFF Research Database (Denmark)

    Betto, Maurizio; Jørgensen, John Leif; Jørgensen, Peter Siegbjørn

    2006-01-01

    Deep space exploration is in the agenda of the major space agencies worldwide and at least the European Space Agency (SMART & Aurora Programs) and the American NASA (New Millennium Program) have set up programs to allow the development and the demonstration of technologies that can reduce the risks...... and the costs of the deep space missions. Navigation is the Achilles' heel of deep space. Being performed on ground, it imposes considerable constraints on the system and the operations, it is very expensive to execute, especially when the mission lasts several years and, above all, it is not failure tolerant....... Nevertheless, up to now, ground navigation has been the only possible solution. The technological breakthrough of advanced star trackers, like the micro-advanced stellar compass (mu ASC) might change this situation. Indeed, exploiting the capabilities of this instrument, the authors have devised a method...

  14. Systems and Methods for Determining Inertial Navigation System Faults

    Science.gov (United States)

    Bharadwaj, Raj Mohan (Inventor); Bageshwar, Vibhor L. (Inventor); Kim, Kyusung (Inventor)

    2017-01-01

    An inertial navigation system (INS) includes a primary inertial navigation system (INS) unit configured to receive accelerometer measurements from an accelerometer and angular velocity measurements from a gyroscope. The primary INS unit is further configured to receive global navigation satellite system (GNSS) signals from a GNSS sensor and to determine a first set of kinematic state vectors based on the accelerometer measurements, the angular velocity measurements, and the GNSS signals. The INS further includes a secondary INS unit configured to receive the accelerometer measurements and the angular velocity measurements and to determine a second set of kinematic state vectors of the vehicle based on the accelerometer measurements and the angular velocity measurements. A health management system is configured to compare the first set of kinematic state vectors and the second set of kinematic state vectors to determine faults associated with the accelerometer or the gyroscope based on the comparison.

  15. Inertial Effects on Finite Length Pipe Seismic Response

    Directory of Open Access Journals (Sweden)

    Virginia Corrado

    2012-01-01

    Full Text Available A seismic analysis for soil-pipe interaction which accounts for length and constraining conditions at the ends of a continuous pipe is developed. The Winkler model is used to schematize the soil-structure interaction. The approach is focused on axial strains, since bending strains in a buried pipe due to the wave propagation are typically a second-order effect. Unlike many works, the inertial terms are considered in solving equations. Accurate numerical simulations are carried out to show the influence of pipe length and constraint conditions on the pipe seismic strain. The obtained results are compared with results inferred from other models present in the literature. For free-end pipelines, inertial effects have significant influence only for short length. On the contrary, their influence is always important for pinned pipes. Numerical simulations show that a simple rigid model can be used for free-end pipes, whereas pinned pipes need more accurate models.

  16. Near-Inertial Internal Gravity Waves in the Ocean.

    Science.gov (United States)

    Alford, Matthew H; MacKinnon, Jennifer A; Simmons, Harper L; Nash, Jonathan D

    2016-01-01

    We review the physics of near-inertial waves (NIWs) in the ocean and the observations, theory, and models that have provided our present knowledge. NIWs appear nearly everywhere in the ocean as a spectral peak at and just above the local inertial period f, and the longest vertical wavelengths can propagate at least hundreds of kilometers toward the equator from their source regions; shorter vertical wavelengths do not travel as far and do not contain as much energy, but lead to turbulent mixing owing to their high shear. NIWs are generated by a variety of mechanisms, including the wind, nonlinear interactions with waves of other frequencies, lee waves over bottom topography, and geostrophic adjustment; the partition among these is not known, although the wind is likely the most important. NIWs likely interact strongly with mesoscale and submesoscale motions, in ways that are just beginning to be understood.

  17. Measuring contact-line mobility during inertial spreading

    Science.gov (United States)

    Steen, Paul; Daniel, Susan; Xia, Yi

    2016-11-01

    During "inertial spreading", when inertia drives a partially wetting liquid across a solid, the role of bulk viscosity may be neglected. For such inertial-capillary motions, behavior of the moving contact-line (CL) can be understood within the context of ideal (or nearly ideal) fluid motion, provided an alternate to the Voinov-Hocking-Cox model of mobility is adopted. The alternate we adopt is the so-called Hocking condition. In this talk, we report experiments with Resonantly-Driven Droplets (RDD) whereby the bulk resonance of the drop amplifies the small and fast CL motion sufficiently to be measurable. The RDD approach enables us to measure a CL mobility and to infer a CL dissipation for droplets on a number of hydrophobic surfaces, surfaces with varying contact-angle hysteresis. Our results are compared to prior results in the literature, measured with alternative approaches. National Science Foundation Grant No. CBET-1236582.

  18. Inertial Measurements Based Velocity-free Attitude Stabilization

    CERN Document Server

    Tayebi, A; Benallegue, A

    2012-01-01

    The existing attitude controllers (without angular velocity measurements) involve explicitly the orientation (\\textit{e.g.,} the unit-quaternion) in the feedback. Unfortunately, there does not exist any sensor that directly measures the orientation of a rigid body, and hence, the attitude must be reconstructed using a set of inertial vector measurements as well as the angular velocity (which is assumed to be unavailable in velocity-free control schemes). To overcome this \\textit{circular reasoning}-like problem, we propose a velocity-free attitude stabilization control scheme relying solely on inertial vector measurements. The originality of this control strategy stems from the fact that the reconstruction of the attitude as well as the angular velocity measurements are not required at all. Moreover, as a byproduct of our design approach, the proposed controller does not lead to the unwinding phenomenon encountered in unit-quaternion based attitude controllers.

  19. Quantum correlations in non-inertial cavity systems

    Science.gov (United States)

    Harsij, Zeynab; Mirza, Behrouz

    2016-10-01

    Non-inertial cavities are utilized to store and send Quantum Information between mode pairs. A two-cavity system is considered where one is inertial and the other accelerated in a finite time. Maclaurian series are applied to expand the related Bogoliubov coefficients and the problem is treated perturbatively. It is shown that Quantum Discord, which is a measure of quantumness of correlations, is degraded periodically. This is almost in agreement with previous results reached in accelerated systems where increment of acceleration decreases the degree of quantum correlations. As another finding of the study, it is explicitly shown that degradation of Quantum Discord disappears when the state is in a single cavity which is accelerated for a finite time. This feature makes accelerating cavities useful instruments in Quantum Information Theory.

  20. Diagnosing magnetized liner inertial fusion experiments on Z

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S. B., E-mail: sbhanse@sandia.gov; Gomez, M. R.; Sefkow, A. B.; Slutz, S. A.; Sinars, D. B.; Hahn, K. D.; Harding, E. C.; Knapp, P. F.; Schmit, P. F.; Awe, T. J.; McBride, R. D.; Jennings, C. A.; Geissel, M.; Harvey-Thompson, A. J.; Peterson, K. J.; Rovang, D. C.; Chandler, G. A.; Cooper, G. W.; Cuneo, M. E.; Hess, M. H. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States); and others

    2015-05-15

    Magnetized Liner Inertial Fusion experiments performed at Sandia's Z facility have demonstrated significant thermonuclear fusion neutron yields (∼10{sup 12} DD neutrons) from multi-keV deuterium plasmas inertially confined by slow (∼10 cm/μs), stable, cylindrical implosions. Effective magnetic confinement of charged fusion reactants and products is signaled by high secondary DT neutron yields above 10{sup 10}. Analysis of extensive power, imaging, and spectroscopic x-ray measurements provides a detailed picture of ∼3 keV temperatures, 0.3 g/cm{sup 3} densities, gradients, and mix in the fuel and liner over the 1–2 ns stagnation duration.

  1. Phase transitions in the distribution of inelastically colliding inertial particles

    CERN Document Server

    Belan, Sergey; Falkovich, Gregory

    2015-01-01

    It was recently suggested that the sign of particle drift in inhomogeneous temperature or turbulence depends on the particle inertia: weakly inertial particles localize near minima of temperature or turbulence intensity (effects known as thermophoresis and turbophoresis), while strongly inertial particles fly away from minima in an unbounded space. The problem of a particle near minima of turbulence intensity is related to that of two particles in a random flow, so that the localization-delocalization transition in the former corresponds to the path-coalescence transition in the latter. The transition is signaled by the sign change of the Lyapunov exponent that characterizes the mean rate of particle approach to the minimum (which could be wall or another particle). Here we solve analytically this problem for inelastic collisions and derive the phase diagram for the transition in the inertia-inelasticity plane. An important feature of the phase diagram is the region of inelastic collapse: if the restitution c...

  2. The effect of surface wettability on inertial pouring flows

    CERN Document Server

    Bouwhuis, Wilco

    2015-01-01

    A liquid poured from a curved solid surface can separate as a steady jet or sheet, or trickle down along the solid surface. It was shown by Duez et al. [Phys. Rev. Lett. 104, 084503 (2010)] that surface wettability controls the separation of an inertial flow from a solid surface to an unexpected degree, which was further motivated by an inertial-capillary adhesion model. In this paper we extend the analysis by a control volume calculation that takes into account the velocity profile within the flowing layer, supported by Boundary Integral potential flow simulations, and the detailed capillary forces induced by the local curvatures of the sheet. Our analysis captures the appearance of a critical Weber number below which no steady separated solutions can be sustained. We investigate the dependence of the critical Weber number on the wettability and sharpness of the edge of the curved solid, and recover the key experimental trends.

  3. Next-generation laser for inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, C; Bibeau, C; Bayramian, A; Beach, R; Ebbers, C A; Emanuel, M; Freitas, B; Fulkerson, S; Honea, E; Krupke, B; Lawson, J; Orth, C; Payne, S; Petty, C; Powell, H; Schaffers, K; Skidmore, J; Smith, L; Sutton, S; Telford, S

    1998-03-13

    We are developing and building the ''Mercury'' laser system as the first in a series of a new generation of diode-pumped solid-state lasers (DPSSL) for advanced high energy density (HED) physics experiments at LLNL. Mercury will be the first integrated demonstration of a scalable laser architecture compatible with advanced Inertial Confinement Fusion (ICF) goals. Primary performance goals include 10% efficiencies at 10 Hz and a <10 ns pulse with l {omega} energies of 100 J and with 2 {omega}/3 {omega} frequency conversion. Achieving this performance will provide a near term capability for HED experiments and prove the potential of DPSSLs for inertial fusion energy (IFE).

  4. Numerical Analysis of Vibrations of Structures under Moving Inertial Load

    CERN Document Server

    Bajer, Czeslaw I

    2012-01-01

    Moving inertial loads are applied to structures in civil engineering, robotics, and mechanical engineering. Some fundamental books exist, as well as thousands of research papers. Well known is the book by L. Frýba, Vibrations of Solids and Structures Under Moving Loads, which describes almost all problems concerning non-inertial loads. This book presents broad description of numerical tools successfully applied to structural dynamic analysis. Physically we deal with non-conservative systems. The discrete approach formulated with the use of the classical finite element method results in elemental matrices, which can be directly added to global structure matrices. A more general approach is carried out with the space-time finite element method. In such a case, a trajectory of the moving concentrated parameter in space and time can be simply defined. We consider structures described by pure hyperbolic differential equations such as strings and structures described by hyperbolic-parabolic differential equations ...

  5. Atom lasers: Production, properties and prospects for precision inertial measurement

    Energy Technology Data Exchange (ETDEWEB)

    Robins, N.P., E-mail: nick.robins@anu.edu.au; Altin, P.A.; Debs, J.E.; Close, J.D.

    2013-08-20

    We review experimental progress on atom lasers out-coupled from Bose–Einstein condensates, and consider the properties of such beams in the context of precision inertial sensing. The atom laser is the matter-wave analogue of the optical laser. Both devices rely on Bose-enhanced scattering to produce a macroscopically populated trapped mode that is output-coupled to produce an intense beam. In both cases, the beams often display highly desirable properties such as low divergence, high spectral flux and a simple spatial mode that make them useful in practical applications, as well as the potential to perform measurements at or below the quantum projection noise limit. Both devices display similar second-order correlations that differ from thermal sources. Because of these properties, atom lasers are a promising source for application to precision inertial measurements.

  6. Nonlinear laser-plasma interaction in magnetized liner inertial fusion

    Science.gov (United States)

    Geissel, Matthias; Awe, T. J.; Bliss, D. E.; Campbell, M. E.; Gomez, M. R.; Harding, E.; Harvey-Thompson, A. J.; Hansen, S. B.; Jennings, C.; Kimmel, M. W.; Knapp, P.; Lewis, S. M.; McBride, R. D.; Peterson, K.; Schollmeier, M.; Scoglietti, D. J.; Sefkow, A. B.; Shores, J. E.; Sinars, D. B.; Slutz, S. A.; Smith, I. C.; Speas, C. S.; Vesey, R. A.; Porter, J. L.

    2016-03-01

    Sandia National Laboratories is pursuing a variation of Magneto-Inertial Fusion called Magnetized Liner Inertial Fusion, or MagLIF. The MagLIF approach requires magnetization of the deuterium fuel, which is accomplished by an initial external B-Field and laser-driven pre-heat. While magnetization is crucial to the concept, it is challenging to couple sufficient energy to the fuel, since laser-plasma instabilities exist, and a compromise between laser spot size, laser entrance window thickness, and fuel density must be found. Nonlinear processes in laser plasma interaction, or laser-plasma instabilities (LPI), complicate the deposition of laser energy by enhanced absorption, backscatter, filamentation and beam-spray. Key LPI processes are determined, and mitigation methods are discussed. Results with and without improvement measures are presented.

  7. On the electromagnetic origin of inertia and inertial mass

    CERN Document Server

    Martins, Alexandre A

    2008-01-01

    We address the problem of inertial property of matter through analysis of the motion of an extended charged particle. Our approach is based on the continuity equation for momentum (Newton's second law) taking due account of the vector potential and its convective derivative. We obtain a development in terms of retarded potentials allowing an intuitive physical interpretation of its main terms. The inertial property of matter is then discussed in terms of a kind of induction law related to the extended charged particle's own vector potential. Moreover, it is obtained a force term that represents a drag force acting on the charged particle when in motion relatively to its own vector potential field lines. The time rate of variation of the particle's vector potential leads to the acceleration inertia reaction force, equivalent to the Schott term responsible for the source of the radiation field. We also show that the velocity dependent term of the particle's vector potential is connected with the relativistic in...

  8. Hydrodynamic interaction of swimming organisms in an inertial regime

    Science.gov (United States)

    Li, Gaojin; Ostace, Anca; Ardekani, Arezoo M.

    2016-11-01

    We numerically investigate the hydrodynamic interaction of swimming organisms at small to intermediate Reynolds number regimes, i.e., Re˜O (0.1 -100 ) , where inertial effects are important. The hydrodynamic interaction of swimming organisms in this regime is significantly different from the Stokes regime for microorganisms, as well as the high Reynolds number flows for fish and birds, which involves strong flow separation and detached vortex structures. Using an archetypal swimmer model, called a "squirmer," we find that the inertial effects change the contact time and dispersion dynamics of a pair of pusher swimmers, and trigger hydrodynamic attraction for two pullers. These results are potentially important in investigating predator-prey interactions, sexual reproduction, and the encounter rate of marine organisms such as copepods, ctenophora, and larvae.

  9. Inertial wave and zonal flow in librating spherical shells

    CERN Document Server

    Lin, Yufeng; Calkin, Michael A

    2014-01-01

    We numerically study the inertial waves and zonal flows in spherical shells driven by longitudinal libration, an oscillatory variation of rotation rate. Internal shear layers are generated due to breakdown of the Ekman boundary layer at critical latitudes. Our numerical results validate the scaling laws of internal shear layers predicted by previous studies. Mean zonal flows are driven by the non-linear interaction in the boundary layers. Non-linear interaction of inertial waves in the interior fluids has no significant contribution to the zonal flow. Multiple geostrophic shear layers are generated due to non-linearities in the boundary layers at critical latitudes and reflection points of internal shear layers. We also investigate the scaling laws of geostrophic shear layers and extrapolate the results to the planetary setting.

  10. Inertial modes of non-stratified superfluid neutron stars

    CERN Document Server

    Prix, R; Andersson, N

    2004-01-01

    We present results concerning adiabatic inertial-mode oscillations of non-stratified superfluid neutron stars in Newtonian gravity, using the anelastic and slow-rotation approximations. We consider a simple two-fluid model of a superfluid neutron star, where one fluid consists of the superfluid neutrons and the second fluid contains all the comoving constituents (protons, electrons). The two fluids are assumed to be ``free'' in the sense that vortex-mediated forces like mutual friction or pinning are absent, but they can be coupled by the equation of state, in particular by entrainment. The stationary background consists of the two fluids rotating uniformly around the same axis with potentially different rotation rates. We study the special cases of co-rotating backgrounds, vanishing entrainment, and the purely toroidal r-modes, analytically. We calculate numerically the eigenfunctions and frequencies of inertial modes in the general case of non co-rotating backgrounds, and study their dependence on the relat...

  11. Damping strapdown inertial navigation system based on a Kalman filter

    Science.gov (United States)

    Zhao, Lin; Li, Jiushun; Cheng, Jianhua; Hao, Yong

    2016-11-01

    A damping strapdown inertial navigation system (DSINS) can effectively suppress oscillation errors of strapdown inertial navigation systems (SINSs) and improve the navigation accuracy of SINSs. Aiming at overcoming the disadvantages of traditional damping methods, a DSINS, based on a Kalman filter (KF), is proposed in this paper. Using the measurement data of accelerometers and calculated navigation parameters during the navigation process, the expression of the observation equation is derived. The calculation process of the observation in both the internal damping state and the external damping state is presented. Finally, system oscillation errors are compensated by a KF. Simulation and test results show that, compared with traditional damping methods, the proposed method can reduce system overshoot errors and shorten the convergence time of oscillation errors effectively.

  12. Enstrophy inertial range dynamics in generalized two-dimensional turbulence

    Science.gov (United States)

    Iwayama, Takahiro; Watanabe, Takeshi

    2016-07-01

    We show that the transition to a k-1 spectrum in the enstrophy inertial range of generalized two-dimensional turbulence can be derived analytically using the eddy damped quasinormal Markovianized (EDQNM) closure. The governing equation for the generalized two-dimensional fluid system includes a nonlinear term with a real parameter α . This parameter controls the relationship between the stream function and generalized vorticity and the nonlocality of the dynamics. An asymptotic analysis accounting for the overwhelming dominance of nonlocal triads allows the k-1 spectrum to be derived based upon a scaling analysis. We thereby provide a detailed analytical explanation for the scaling transition that occurs in the enstrophy inertial range at α =2 in terms of the spectral dynamics of the EDQNM closure, which extends and enhances the usual phenomenological explanations.

  13. Pedestrian Navigation Using Foot-Mounted Inertial Sensor and LIDAR.

    Science.gov (United States)

    Pham, Duy Duong; Suh, Young Soo

    2016-01-19

    Foot-mounted inertial sensors can be used for indoor pedestrian navigation. In this paper, to improve the accuracy of pedestrian location, we propose a method using a distance sensor (LIDAR) in addition to an inertial measurement unit (IMU). The distance sensor is a time of flight range finder with 30 m measurement range (at 33.33 Hz). Using a distance sensor, walls on corridors are automatically detected. The detected walls are used to correct the heading of the pedestrian path. Through experiments, it is shown that the accuracy of the heading is significantly improved using the proposed algorithm. Furthermore, the system is shown to work robustly in indoor environments with many doors and passing people.

  14. INERTIAL FUSION DRIVEN BY INTENSE HEAVY-ION BEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, W. M.; Friedman, A.; Grote, D. P.; Barnard, J. J.; Cohen, R. H.; Dorf, M. A.; Lund, S. M.; Perkins, L. J.; Terry, M. R.; Logan, B. G.; Bieniosek, F. M.; Faltens, A.; Henestroza, E.; Jung, J. Y.; Kwan, J. W.; Lee, E. P.; Lidia, S. M.; Ni, P. A.; Reginato, L. L.; Roy, P. K.; Seidl, P. A.; Takakuwa, J. H.; Vay, J.-L.; Waldron, W. L.; Davidson, R. C.; Gilson, E. P.; Kaganovich, I. D.; Qin, H.; Startsev, E.; Haber, I.; Kishek, R. A.; Koniges, A. E.

    2011-03-31

    Intense heavy-ion beams have long been considered a promising driver option for inertial-fusion energy production. This paper briefly compares inertial confinement fusion (ICF) to the more-familiar magnetic-confinement approach and presents some advantages of using beams of heavy ions to drive ICF instead of lasers. Key design choices in heavy-ion fusion (HIF) facilities are discussed, particularly the type of accelerator. We then review experiments carried out at Lawrence Berkeley National Laboratory (LBNL) over the past thirty years to understand various aspects of HIF driver physics. A brief review follows of present HIF research in the US and abroad, focusing on a new facility, NDCX-II, being built at LBNL to study the physics of warm dense matter heated by ions, as well as aspects of HIF target physics. Future research directions are briefly summarized.

  15. MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones

    CERN Document Server

    Dotter, Aaron

    2016-01-01

    I describe a method to transform a set of stellar evolution tracks onto a uniform basis and then interpolate within that basis to construct stellar isochrones. The method accommodates a broad range of stellar types, from substellar objects to high-mass stars, and phases of evolution, from the pre-main sequence to the white dwarf cooling sequence. I discuss situations in which stellar physics leads to departures from the otherwise monotonic relation between initial stellar mass and lifetime and how these may be dealt with in isochrone construction. I close with convergence tests and recommendations for the number of points in the uniform basis and the mass between tracks in the original grid required in order to achieve a certain level of accuracy in the resulting isochrones. The programs that implement these methods are free and open-source; they may be obtained from the project webpage.

  16. Fermionic entanglement extinction in non-inertial frames

    CERN Document Server

    Montero, M; Martin-Martinez, E

    2011-01-01

    We study families of fermionic field states in non-inertial frames which show no entanglement survival in the infinite acceleration limit. We generalise some recent results where some particular examples of such states where found. We analyse the abundance and characteristics of the states showing this behaviour and discuss its relation with the statistics of the field. We also consider the phenomenon beyond the single mode approximation

  17. Inertial confinement fusion driven by long wavelength electromagnetic pulses

    Institute of Scientific and Technical Information of China (English)

    Baifei; Shen; Xueyan; Zhao; Longqing; Yi; Wei; Yu; Zhizhan; Xu

    2013-01-01

    A method for inertial confinement fusion driven by powerful long wavelength electromagnetic pulses(EMPs), such as CO2 laser pulses or high power microwave pulses, is proposed. Due to the high efficiency of generating such long wavelength electromagnetic pulses, this method is especially important for the future fusion electricity power. Special fuel targets are designed to overcome the shortcomings of the long wavelength electromagnetic pulses.

  18. Vision-aided inertial navigation system for robotic mobile mapping

    Science.gov (United States)

    Bayoud, Fadi; Skaloud, Jan

    2008-04-01

    A mapping system by vision-aided inertial navigation was developed for areas where GNSS signals are unreachable. In this framework, a methodology on the integration of vision and inertial sensors is presented, analysed and tested. The system employs the method of “SLAM: Simultaneous Localisation And Mapping” where the only external input available to the system at the beginning of the mapping mission is a number of features with known coordinates. SLAM is a term used in the robotics community to describe the problem of mapping the environment and at the same time using this map to determine the location of the mapping device. Differing from the robotics approach, the presented development stems from the frameworks of photogrammetry and kinematic geodesy that are merged in two filters that run in parallel: the Least-Squares Adjustment (LSA) for features coordinates determination and the Kalman filter (KF) for navigation correction. To test this approach, a mapping system-prototype comprising two CCD cameras and one Inertial Measurement Unit (IMU) is introduced. Conceptually, the outputs of the LSA photogrammetric resection are used as the external measurements for the KF that corrects the inertial navigation. The filtered position and orientation are subsequently employed in the photogrammetric intersection to map the surrounding features that are used as control points for the resection in the next epoch. We confirm empirically the dependency of navigation performance on the quality of the images and the number of tracked features, as well as on the geometry of the stereo-pair. Due to its autonomous nature, the SLAM's performance is further affected by the quality of IMU initialisation and the a-priory assumptions on error distribution. Using the example of the presented system we show that centimetre accuracy can be achieved in both navigation and mapping when the image geometry is optimal.

  19. Inertial waste separation system for zero G WMS

    Science.gov (United States)

    1971-01-01

    The design, operation, and flight test are presented for an inertial waste separation system. Training personnel to use this system under simulated conditions is also discussed. Conclusions indicate that before the system is usable in zero gravity environments, a mirror for the user's guidance should be installed, the bounce cycle and bag changing system should be redesigned, and flange clips should be added to improve the user's balance.

  20. A semi-analytic model of magnetized liner inertial fusion

    OpenAIRE

    McBride, Ryan D.; Slutz, Stephen A.

    2015-01-01

    Presented is a semi-analytic model of magnetized liner inertial fusion (MagLIF). This model accounts for several key aspects of MagLIF, including: (1) preheat of the fuel (optionally via laser absorption); (2) pulsed-power-driven liner implosion; (3) liner compressibility with an analytic equation of state, artificial viscosity, internal magnetic pressure, and ohmic heating; (4) adiabatic compression and heating of the fuel; (5) radiative losses and fuel opacity; (6) magnetic flux compression...

  1. Inertial currents in the southern Gulf of Mexico

    OpenAIRE

    G Expósito-Díaz; DA Salas-de León; MA Monreal-Gómez; D Salas-Monreal; F Vázquez-Gutiérrez

    2009-01-01

    Current velocity data recorded from 1 March to 17 June 1997 at four stations in the Bay of Campeche, southern Gulf of Mexico, were used to describe inertial currents. Data were low-pass filtered using a Lanczos filter, and transformed to the frequency domain with the classical Fast Fourier Transform, rotary spectra, and the Morlet Wavelet Method. The strongest total currents developed in the eastern part of the bay, with a dominant east-west component. The predominant direction of the total ...

  2. Inertial quantum sensors using light and matter

    Science.gov (United States)

    Barrett, B.; Bertoldi, A.; Bouyer, P.

    2016-05-01

    The past few decades have seen dramatic progress in our ability to manipulate and coherently control matter-waves. Although the duality between particles and waves has been well tested since de Broglie introduced the matter-wave analog of the optical wavelength in 1924, manipulating atoms with a level of coherence that enables one to use these properties for precision measurements has only become possible with our ability to produce atomic samples exhibiting temperatures of only a few millionths of a degree above absolute zero. Since the initial experiments a few decades ago, the field of atom optics has developed in many ways, with both fundamental and applied significance. The exquisite control of matter waves offers the prospect of a new generation of force sensors exhibiting unprecedented sensitivity and accuracy, for applications from navigation and geophysics to tests of general relativity. Thanks to the latest developments in this field, the first commercial products using this quantum technology are now available. In the future, our ability to create large coherent ensembles of atoms will allow us an even more precise control of the matter-wave and the ability to create highly entangled states for non-classical atom interferometry.

  3. Kinetic properties of fractal stellar media

    Science.gov (United States)

    Chumak, O. V.; Rastorguev, A. S.

    2017-01-01

    Kinetic processes in fractal stellar media are analysed in terms of the approach developed in our earlier paper involving a generalization of the nearest neighbour and random force distributions to fractal media. Diffusion is investigated in the approximation of scale-dependent conditional density based on an analysis of the solutions of the corresponding Langevin equations. It is shown that kinetic parameters (time-scales, coefficients of dynamic friction, diffusion, etc.) for fractal stellar media can differ significantly both qualitatively and quantitatively from the corresponding parameters for a quasi-uniform random media with limited fluctuations. The most important difference is that in the fractal case, kinetic parameters depend on spatial scalelength and fractal dimension of the medium studied. A generalized kinetic equation for stellar media (fundamental equation of stellar dynamics) is derived in the Fokker-Planck approximation with the allowance for the fractal properties of the spatial stellar density distribution. Also derived are its limit forms that can be used to describe small departures of fractal gravitating medium from equilibrium.

  4. Stellarator Coil Design and Plasma Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Long-Poe Ku and Allen H. Boozer

    2010-11-03

    The rich information contained in the plasma response to external magnetic perturbations can be used to help design stellarator coils more effectively. We demonstrate the feasibility by first devel- oping a simple, direct method to study perturbations in stellarators that do not break stellarator symmetry and periodicity. The method applies a small perturbation to the plasma boundary and evaluates the resulting perturbed free-boundary equilibrium to build up a sensitivity matrix for the important physics attributes of the underlying configuration. Using this sensitivity information, design methods for better stellarator coils are then developed. The procedure and a proof-of-principle application are given that (1) determine the spatial distributions of external normal magnetic field at the location of the unperturbed plasma boundary to which the plasma properties are most sen- sitive, (2) determine the distributions of external normal magnetic field that can be produced most efficiently by distant coils, (3) choose the ratios of the magnitudes of the the efficiently produced magnetic distributions so the sensitive plasma properties can be controlled. Using these methods, sets of modular coils are found for the National Compact Stellarator Experiment (NCSX) that are either smoother or can be located much farther from the plasma boundary than those of the present design.

  5. Saturation of Stellar Winds from Young Suns

    CERN Document Server

    Suzuki, Takeru K; Kataoka, Ryuho; Kato, Yoshiaki; Matsumoto, Takuma; Miyahara, Hiroko; Tsuneta, Saku

    2013-01-01

    (Abridged)We investigate mass losses via stellar winds from sun-like main sequence stars with a wide range of activity levels. We perform forward-type magnetohydrodynamical numerical experiments for Alfven wave-driven stellar winds with a wide range of the input Poynting flux from the photosphere. Increasing the magnetic field strength and the turbulent velocity at the stellar photosphere from the current solar level, the mass loss rate rapidly increases at first owing to the suppression of the reflection of the Alfven waves. The surface materials are lifted up by the magnetic pressure associated with the Alfven waves, and the cool dense chromosphere is intermittently extended to 10-20% of the stellar radius. The densities of the corona and transition region above the chromosphere is also high, which leads to efficient radiative losses. Eventually most of the input Poynting energy from the stellar surface escapes by the radiation. As a result, there is no more sufficient energy remained for the kinetic energy...

  6. Capillary-Inertial Colloidal Catapult upon Drop Coalescence

    Science.gov (United States)

    Chavez, Roger; Liu, Fangjie; Feng, James; Chen, Chuan-Hua

    2014-11-01

    To discharge micron-sized particles such as colloidal contaminants and biological spores, an enormous power density is needed to compete against the strong adhesive forces between the small particles and the supporting surface as well as the significant air friction exerted on the particles. Here, we demonstrate a colloidal catapult that achieves such a high power density by extracting surface energy released upon drop coalescence within an extremely short time period, which is governed by the capillary-inertial process converting the released surface energy into the bulk inertia of the merged drop. When two drops coalesce on top of a spherical particle, the resulting capillary-inertial oscillation is perturbed by the solid particle, giving rise to a net momentum eventually propelling the particle to launch from the supporting surface. The measured launching velocity follows a scaling law that accounts for the redistribution of the momentum of the merged drop onto the particle-drop complex, and is therefore proportional to the capillary-inertial velocity characterizing the coalescing drops. The interfacial flow process associated with the colloidal catapult is elucidated with both high-speed imaging and phase-field simulations.

  7. Application of inertial navigation to wellbore positional surveying

    Energy Technology Data Exchange (ETDEWEB)

    Watts, A.C.

    1982-06-01

    There is an increasing need for higher accuracy in wellbore directional and positional surveying than is currently available using conventional techniques. Among the factors contributing to this need are closed interspacing of wells particularly from offshore platforms, deeper and more highly deviated wells, smaller target formations and the requirement for rapid drilling of relief wells in the case of blowouts. The application of inertial navigation system (INS) of suitable size and cost for this type of application is not inherently accurate enough to offer significant improvements in well-surveying accuracy. Techniques to improve accuracy are, in general, based on the fact that the dynamics associated with the propagation of the navigator errors are very well known. Inertial systems are routinely aided using external data from a number of sources. Such aiding may take the form of an external position or velocity measurement which is compared to the position or velocity indicated by the navigator. Kalman filter theory provides a convenient formulation for generation of a minimum variance estimate of the state vector of a linear system. The theory may be extended to the nonlinear case through the use of linearization about a state trajectory. This approach is currently seeing wide use in aiding of inertial navigation systems. The approach proposed here would use the Kalman filter formulation for estimation of the INS errors and updating of the navigator. This formulation also provides a structure for estimation of various instrument parameters which should improve system performance.

  8. Inertial particles in a shearless mixing layer: direct numerical simulations

    Science.gov (United States)

    Ireland, Peter; Collins, Lance

    2010-11-01

    Entrainment, the drawing in of external fluid by a turbulent flow, is present in nearly all turbulent processes, from exhaust plumes to oceanic thermoclines to cumulus clouds. While the entrainment of fluid and of passive scalars in turbulent flows has been studied extensively, comparatively little research has been undertaken on inertial particle entrainment. We explore entrainment of inertial particles in a shearless mixing layer across a turbulent-non-turbulent interface (TNI) and a turbulent-turbulent interface (TTI) through direct numerical simulation (DNS). Particles are initially placed on one side of the interface and are advanced in time in decaying turbulence. Our results show that the TTI is more efficient in mixing droplets than the TNI. We also find that without the influence of gravity, over the range of Stokes numbers present in cumulus clouds, particle concentration statistics are essentially independent of the dissipation scale Stokes number. The DNS data agrees with results from experiments performed in a wind tunnel with close parametric overlap. We anticipate that a better understanding of the role of gravity and turbulence in inertial particle entrainment will lead to improved cloud evolution predictions and more accurate climate models. Sponsored by the U.S. NSF.

  9. A Visual-aided Inertial Navigation and Mapping System

    Directory of Open Access Journals (Sweden)

    Rodrigo Munguía

    2016-05-01

    Full Text Available State estimation is a fundamental necessity for any application involving autonomous robots. This paper describes a visual-aided inertial navigation and mapping system for application to autonomous robots. The system, which relies on Kalman filtering, is designed to fuse the measurements obtained from a monocular camera, an inertial measurement unit (IMU and a position sensor (GPS. The estimated state consists of the full state of the vehicle: the position, orientation, their first derivatives and the parameter errors of the inertial sensors (i.e., the bias of gyroscopes and accelerometers. The system also provides the spatial locations of the visual features observed by the camera. The proposed scheme was designed by considering the limited resources commonly available in small mobile robots, while it is intended to be applied to cluttered environments in order to perform fully vision-based navigation in periods where the position sensor is not available. Moreover, the estimated map of visual features would be suitable for multiple tasks: i terrain analysis; ii three dimensional (3D scene reconstruction; iii localization, detection or perception of obstacles and generating trajectories to navigate around these obstacles; and iv autonomous exploration. In this work, simulations and experiments with real data are presented in order to validate and demonstrate the performance of the proposal.

  10. Analysis of the correlation dimension for inertial particles

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Kristian [Department of Physics, University of Tor Vergata, 00133 Rome (Italy); Department of Physics, Göteborg University, 41296 Gothenburg (Sweden); Mehlig, Bernhard [Department of Physics, Göteborg University, 41296 Gothenburg (Sweden); Wilkinson, Michael [Department of Mathematics and Statistics, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2015-07-15

    We obtain an implicit equation for the correlation dimension which describes clustering of inertial particles in a complex flow onto a fractal measure. Our general equation involves a propagator of a nonlinear stochastic process in which the velocity gradient of the fluid appears as additive noise. When the long-time limit of the propagator is considered our equation reduces to an existing large-deviation formalism from which it is difficult to extract concrete results. In the short-time limit, however, our equation reduces to a solvability condition on a partial differential equation. In the case where the inertial particles are much denser than the fluid, we show how this approach leads to a perturbative expansion of the correlation dimension, for which the coefficients can be obtained exactly and in principle to any order. We derive the perturbation series for the correlation dimension of inertial particles suspended in three-dimensional spatially smooth random flows with white-noise time correlations, obtaining the first 33 non-zero coefficients exactly.

  11. Robust Active Suspension Design Subject to Vehicle Inertial Parameter Variations

    Institute of Scientific and Technical Information of China (English)

    Hai-Ping Du; Nong Zhang

    2010-01-01

    This paper presents an approach in designing a robust controller for vehicle suspensions considering changes in vehicle inertial properties. A four-degree-of-freedom half-car model with active suspension is studied in this paper, and three main performance requirements are considered. Among these requirements, the ride comfort performance is optimized by minimizing the H∞ norm of the transfer function from the road disturbance to the sprung mass acceleration, while the road holding performance and the suspension deflection limitation are guaranteed by constraining the generalized H2 (GH2) norms of the transfer functions from the road disturbance to the dynamic tyre load and the suspension deflection to be less than their hard limits, respectively. At the same time, the controller saturation problem is considered by constraining its peak response output to be less than a given limit using the GH2 norm as well. By solving the finite number of linear matrix inequalities (LMIs) with the minimization optimization procedure, the controller gains, which are dependent on the time-varying inertial parameters, can be obtained. Numerical simulations on both frequency and bump responses show that the designed parameter-dependent controller can achieve better active suspension performance compared with the passive suspension in spite of the variations of inertial parameters.

  12. Inertial Pocket Navigation System: Unaided 3D Positioning

    Directory of Open Access Journals (Sweden)

    Estefania Munoz Diaz

    2015-04-01

    Full Text Available Inertial navigation systems use dead-reckoning to estimate the pedestrian’s position. There are two types of pedestrian dead-reckoning, the strapdown algorithm and the step-and-heading approach. Unlike the strapdown algorithm, which consists of the double integration of the three orthogonal accelerometer readings, the step-and-heading approach lacks the vertical displacement estimation. We propose the first step-and-heading approach based on unaided inertial data solving 3D positioning. We present a step detector for steps up and down and a novel vertical displacement estimator. Our navigation system uses the sensor introduced in the front pocket of the trousers, a likely location of a smartphone. The proposed algorithms are based on the opening angle of the leg or pitch angle. We analyzed our step detector and compared it with the state-of-the-art, as well as our already proposed step length estimator. Lastly, we assessed our vertical displacement estimator in a real-world scenario. We found that our algorithms outperform the literature step and heading algorithms and solve 3D positioning using unaided inertial data. Additionally, we found that with the pitch angle, five activities are distinguishable: standing, sitting, walking, walking up stairs and walking down stairs. This information complements the pedestrian location and is of interest for applications, such as elderly care.

  13. Inertial Pocket Navigation System: Unaided 3D Positioning.

    Science.gov (United States)

    Diaz, Estefania Munoz

    2015-04-17

    Inertial navigation systems use dead-reckoning to estimate the pedestrian's position. There are two types of pedestrian dead-reckoning, the strapdown algorithm and the step-and-heading approach. Unlike the strapdown algorithm, which consists of the double integration of the three orthogonal accelerometer readings, the step-and-heading approach lacks the vertical displacement estimation. We propose the first step-and-heading approach based on unaided inertial data solving 3D positioning. We present a step detector for steps up and down and a novel vertical displacement estimator. Our navigation system uses the sensor introduced in the front pocket of the trousers, a likely location of a smartphone. The proposed algorithms are based on the opening angle of the leg or pitch angle. We analyzed our step detector and compared it with the state-of-the-art, as well as our already proposed step length estimator. Lastly, we assessed our vertical displacement estimator in a real-world scenario. We found that our algorithms outperform the literature step and heading algorithms and solve 3D positioning using unaided inertial data. Additionally, we found that with the pitch angle, five activities are distinguishable: standing, sitting, walking, walking up stairs and walking down stairs. This information complements the pedestrian location and is of interest for applications, such as elderly care.

  14. 3D environment capture from monocular video and inertial data

    Science.gov (United States)

    Clark, R. Robert; Lin, Michael H.; Taylor, Colin J.

    2006-02-01

    This paper presents experimental methods and results for 3D environment reconstruction from monocular video augmented with inertial data. One application targets sparsely furnished room interiors, using high quality handheld video with a normal field of view, and linear accelerations and angular velocities from an attached inertial measurement unit. A second application targets natural terrain with manmade structures, using heavily compressed aerial video with a narrow field of view, and position and orientation data from the aircraft navigation system. In both applications, the translational and rotational offsets between the camera and inertial reference frames are initially unknown, and only a small fraction of the scene is visible in any one video frame. We start by estimating sparse structure and motion from 2D feature tracks using a Kalman filter and/or repeated, partial bundle adjustments requiring bounded time per video frame. The first application additionally incorporates a weak assumption of bounding perpendicular planes to minimize a tendency of the motion estimation to drift, while the second application requires tight integration of the navigational data to alleviate the poor conditioning caused by the narrow field of view. This is followed by dense structure recovery via graph-cut-based multi-view stereo, meshing, and optional mesh simplification. Finally, input images are texture-mapped onto the 3D surface for rendering. We show sample results from multiple, novel viewpoints.

  15. Movement-related potentials accompanying unilateral and bilateral finger movements with different inertial loads.

    Science.gov (United States)

    Kristeva, R; Cheyne, D; Lang, W; Lindinger, G; Deecke, L

    1990-05-01

    The present study was aimed at investigating the effect of inertial loading on movement-related potentials (MRPs) recorded from the scalps of normal subjects while performing finger movements. Two experiments were performed. Experiment 1. MRPs preceding and accompanying the execution of voluntary, unilateral finger movements were investigated in 8 subjects under the 3 experimental conditions of: no inertial load, small inertial load (250 g), and large inertial load (400 g). A significant effect of the inertial load on Bereitschaftspotential (BP) amplitude was observed for the 100 msec period preceding movement onset (BP -100 to 0) at precentral electrode sites and following movement onset (N0 to 100) at both precentral and parietal electrode sites. Pairwise comparisons revealed that significant effects were due to differences between the loading and non-loading conditions and not for different amounts of loading. No significant differences were observed for BP onset or early BP amplitudes, indicating that scalp negativity immediately prior to, and during, movement onset is primarily influenced by conditions of inertial loading. Experiment 2. This experiment examined the effect of inertial loading on MRPs for bilateral, simultaneous voluntary finger movements in 10 subjects under conditions of: no inertial load, inertial load applied separately to the left and right fingers, and with identical inertial loads applied to both fingers. No significant effect of inertial load on MRP amplitude was observed. These results are contrasted with those of experiment 1 which show significant effects of inertial loading for unilateral movements and are interpreted in terms of the hypothesis that bilateral movement organization involves 'higher' aspects of motor control than those reflecting adjustment to conditions of inertial loading.

  16. Atomic Data for Stellar Astrophysics: from the UV to the IR

    Science.gov (United States)

    Wahlgren, Glenn M.

    2011-01-01

    The study of stars and stellar evolution relies heavily on the analysis of stellar spectra. The need for atomic line data from the ultraviolet (UV) to the infrared (lR) regions is greater now than ever. In the past twenty years, the time since the launch of the Hubble Space Telescope, great progress has been made in acquiring atomic data for UV transitions. The optical wavelength region, now expanded by progress in detector technology, continues to provide motivation for new atomic data. In addition, investments in new instrumentation for ground-based and space observatories has lead to the availability of high-quality spectra at IR wavelengths, where the need for atomic data is most critical. In this review, examples are provided of the progress made in generating atomic data for stellar studies, with a look to the future for addressing the accuracy and completeness of atomic data for anticipated needs.

  17. Laser-Driven Magnetized Liner Inertial Fusion on OMEGA

    Science.gov (United States)

    Barnak, D. H.

    2016-10-01

    Magneto-inertial fusion (MIF) is an approach that combines the implosion and compression of fusion fuel (a hallmark of inertial fusion) with strongly magnetized plasmas that suppress electron heat losses (a hallmark of magnetic fusion). It is of interest because it could potentially reduce some of the traditional velocity, pressure, and convergence ratio requirements of inertial confinement fusion (ICF). The magnetized liner inertial fusion (MagLIF) concept being studied at the Z Pulsed-Power Facility is a key target concept in the U.S. ICF Program. Laser-driven MagLIF is being developed to enable a test of the scaling of MagLIF over a range of absorbed energy from of the order of 20 kJ (on OMEGA) to 500 kJ (on Z). It is also valuable as a platform for studying the key physics of MIF. An energy-scaled point design has been developed for the Omega Laser Facility that is roughly 10 × smaller in linear dimensions than Z MagLIF targets. A 0.6-mm-outer-diam plastic cylinder filled with 2.4 mg/cm3 of D2 is placed in a 10-T axial magnetic field, generated by MIFEDS (magneto-inertial fusion electrical discharge system), the cylinder is compressed by 40 OMEGA beams, and the gas fill is preheated by a single OMEGA beam propagating along the axis. Preheating to >100 eV and axially uniform compression over a 0.7-mm height have been demonstrated, separately, in a series of preparatory experiments that meet our initial expectations. Preliminary results from the first integrated experiments combining magnetization, compression, and preheat will be reported for the first time. The scaling of laser-driven MagLIF from OMEGA up to the 1800 kJ available on the NIF (National Ignition Facility) will also be described briefly. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  18. Electron capture cross sections for stellar nucleosynthesis

    CERN Document Server

    Giannaka, P G

    2015-01-01

    In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasi-particle random-phase approximation (pn-QRPA) and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the above mentioned $e^-$-capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the $^{66}Zn$ isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  19. A method to deconvolve stellar rotational velocities

    CERN Document Server

    Cure, Michel; Cassetti, Julia; Christen, Alejandra

    2014-01-01

    Rotational speed is an important physical parameter of stars and knowing the distribution of stellar rotational velocities is essential for the understanding stellar evolution. However, it cannot be measured directly but the convolution of the rotational speed and the sine of the inclination angle, $v \\sin i$. We developed a method to deconvolve this inverse problem and obtain the cumulative distribution function (CDF) for stellar rotational velocities extending the work of Chandrasekhar & M\\"unch (1950). This method is applied a) to theoretical synthetic data recovering the original velocity distribution with very small error; b) to a sample of about 12.000 field main--sequence stars, corroborating that the velocity distribution function is non--Maxwellian, but is better described by distributions based on the concept of maximum entropy, such as Tsallis or Kaniadakis distribution functions. This is a very robust and novel method that deconvolve the rotational velocity cumulative distribution function fro...

  20. Magnetospheric outflows in young stellar objects

    Directory of Open Access Journals (Sweden)

    Zanni Claudio

    2014-01-01

    Full Text Available Different classes of outflows are associated with the magnetospheric activity of accreting T Tauri protostars. Stellar winds are accelerated along the open field lines anchored in the stellar surface; disk winds (extended or X-type can be launched along the open magnetic surfaces threading the accretion disk; another type of ejection can arise from the region of interaction of the closed magnetosphere with the accretion disk (magnetospheric ejections, conical winds, where the magnetic surfaces undergo quasiperiodic episodes of inflation and reconnection. In this chapter I will present the main dynamical properties of these different types of outflow. Two main issues will be addressed. First, I will try to understand if these ejection phenomena can account for the origin of the jets often observed in young forming stellar systems. Second, I will evaluate the impact of these outflows on the angular momentum evolution of the central protostar.

  1. A daylight experiment for teaching stellar interferometry

    Science.gov (United States)

    Illarramendi, M. A.; Hueso, R.; Zubia, J.; Aldabaldetreku, G.; Durana, G.; Sánchez-Lavega, A.

    2014-07-01

    We discuss the design of a simple experiment that reproduces the operation of the Michelson stellar interferometer. The emission of stellar sources has been simulated using light emerging from circular end-faces of step-index polymer optical fibers and from diffuse reflections of laser beams. Interference fringes have been acquired using a digital camera, coupled to a telescope obscured by a double aperture lid. The experiment is analogous to the classical determination of stellar sizes by Michelson and can be used during the day. Using this experimental set-up, we can determine the size of extended sources, located at a distance of about 75 m from our telescope, with errors less than 25%.

  2. Progress Toward Improved Compact Stellarator Designs

    Science.gov (United States)

    Neilson, G. H.; Brown, T.; Gates, D.; Ku, L. P.; Lazerson, S.; Pomphrey, N.; Reiman, A.; Zarnstorff, M.; Bromberg, L.; Boozer, A.; Harris, J.

    2010-11-01

    Stellarators offer robust physics solutions for MFE challenges-- steady-state operation, disruption elimination, and high-density operation-- but require design improvements to overcome technical risks in the construction and maintenance of future large-scale stellarators. Using the ARIES-CS design (aspect ratio 4.56) as a starting point, compact stellarator designs with improved maintenance characteristics have been developed. By making the outboard legs of the main magnetic field coils nearly straight and parallel, a sector maintenance scheme compatible with high availability becomes possible. Approaches that can allow the main coil requirements to be relaxed in this way are: 1) increase aspect ratio at the expense of compactness, 2) add local removable coils in the maintenance ports for plasma shaping, and 3) use passive conducting tiles made of bulk high-temperature superconducting material to help shape the magnetic field. Such tiles would be arranged on a shaped, segmented internal support structure behind the shield.

  3. Recent advances in modeling stellar interiors (u)

    Energy Technology Data Exchange (ETDEWEB)

    Guzik, Joyce Ann [Los Alamos National Laboratory

    2010-01-01

    Advances in stellar interior modeling are being driven by new data from large-scale surveys and high-precision photometric and spectroscopic observations. Here we focus on single stars in normal evolutionary phases; we will not discuss the many advances in modeling star formation, interacting binaries, supernovae, or neutron stars. We review briefly: (1) updates to input physics of stellar models; (2) progress in two and three-dimensional evolution and hydrodynamic models; (3) insights from oscillation data used to infer stellar interior structure and validate model predictions (asteroseismology). We close by highlighting a few outstanding problems, e.g., the driving mechanisms for hybrid {gamma} Dor/{delta} Sct star pulsations, the cause of giant eruptions seen in luminous blue variables such as {eta} Car and P Cyg, and the solar abundance problem.

  4. On stellar limb darkening and exoplanetary transits

    CERN Document Server

    Howarth, Ian D

    2011-01-01

    This paper examines how to compare stellar limb-darkening coefficients evaluated from model atmospheres with those estimated from photometry. Limb-darkening coefficients derived from light-curve analyses using approximate limb-darkening `laws' are shown to be dependent on system geometry, while different characterizations of a given model atmosphere can give quite different numerical results. These issues are examined in the context of exoplanetary transits, which offer significant advantages over traditional binary-star eclipsing systems in the investigation of stellar limb darkening. `Like for like' comparisons between light-curve analyses and new model-atmosphere results, mediated by synthetic photometry, are conducted for a small sample of stars. Agreement between the resulting synthetic-photometry/atmosphere-model (SPAM) limb-darkening coefficients and empirical values ranges from very good to quite poor, even though there is only a small dispersion in fundamental stellar parameters.

  5. Achieving continuity: a story of stellar magnitude

    Science.gov (United States)

    Evans, Michael S.

    2010-03-01

    Scientists tell a story of 2,000 years of stellar magnitude research that traces back to Hipparchus. This story of continuity in practices serves an important role in scientific education and outreach. STS scholars point out many ways that stories of continuity, like many narratives about science, are disconnected from practices. Yet the story of continuity in stellar magnitude is a powerful scientific achievement precisely because of its connection to practice. The historical development of star catalogues shows how specific recording practices connected past and present in a useful way. The narrative of continuity in stellar magnitude, however else it might be subject to STS critique of narrative, maintains its power because of its connection to practice. I suggest that more attention be paid to connections between practice and narrative in STS, and in particular to the ways that historical practices sustain narratives by connecting past and present.

  6. Simulation and optimisation of turbulence in stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Xanthopoulos, Pavlos; Helander, Per; Turkin, Yuriy; Plunk, Gabriel G.; Bird, Thomas; Proll, Josefine H.E. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); Mynick, Harry [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Jenko, Frank; Goerler, Tobias; Told, Daniel [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2014-07-01

    In tokamaks and stellarators - two leading types of devices used in fusion research - magnetic field lines trace out toroidal surfaces on which the plasma density and temperature are constant, but turbulent fluctuations carry energy across these surfaces to the wall, thus degrading the plasma confinement. Using petaflop-scale simulations, we calculate for the first time the pattern of turbulent structures forming on stellarator magnetic surfaces, and find striking differences relative to tokamaks. The observed sensitivity of the turbulence to the magnetic geometry suggests that there is room for further confinement improvement, in addition to measures already taken to minimise the laminar transport. With an eye towards fully optimised stellarators, we present a proof-of-principle configuration with substantially reduced turbulence compared to an existing design.

  7. Stellar Tidal Streams in External Galaxies

    CERN Document Server

    Carlin, Jeffrey L; Martinez-Delgado, David; Gabany, R Jay

    2016-01-01

    To place the highly substructured stellar halos of the Milky Way and M31 in a larger context of hierarchical galaxy formation, it is necessary to understand the prevalence and properties of tidal substructure around external galaxies. This chapter details the current state of our observational knowledge of streams in galaxies in and beyond the Local Group, which are studied both in resolved stellar populations and in integrated light. Modeling of individual streams in extragalactic systems is hampered by our inability to obtain resolved stellar kinematics in the streams, though many streams contain alternate luminous kinematic tracers, such as globular clusters or planetary nebulae. We compare the observed structures to the predictions of models of galactic halo formation, which provide insight in the number and properties of streams expected around Milky Way like galaxies. More specifically, we discuss the inferences that can be made about stream progenitors based only on observed morphologies. We expand our...

  8. The stellar atmosphere simulation code Bifrost

    CERN Document Server

    Gudiksen, Boris V; Hansteen, Viggo H; Hayek, Wolfgang; Leenaarts, Jorrit; Martínez-Sykora, Juan

    2011-01-01

    Context: Numerical simulations of stellar convection and photospheres have been developed to the point where detailed shapes of observed spectral lines can be explained. Stellar atmospheres are very complex, and very different physical regimes are present in the convection zone, photosphere, chromosphere, transition region and corona. To understand the details of the atmosphere it is necessary to simulate the whole atmosphere since the different layers interact strongly. These physical regimes are very diverse and it takes a highly efficient massively parallel numerical code to solve the associated equations. Aims: The design, implementation and validation of the massively parallel numerical code Bifrost for simulating stellar atmospheres from the convection zone to the corona. Methods: The code is subjected to a number of validation tests, among them the Sod shock tube test, the Orzag-Tang colliding shock test, boundary condition tests and tests of how the code treats magnetic field advection, chromospheric ...

  9. The Spitzer Atlas of Stellar Spectra

    CERN Document Server

    Ardila, David R; Makowiecki, Wojciech; Stauffer, John; Song, Inseok; Rho, Jeonghee; Fajardo-Acosta, Sergio; Hoard, D W; Wachter, Stefanie

    2010-01-01

    We present the Spitzer Atlas of Stellar Spectra (SASS), which includes 159 stellar spectra (5 to 32 mic; R~100) taken with the Infrared Spectrograph on the Spitzer Space Telescope. This Atlas gathers representative spectra of a broad section of the Hertzsprung-Russell diagram, intended to serve as a general stellar spectral reference in the mid-infrared. It includes stars from all luminosity classes, as well as Wolf-Rayet (WR) objects. Furthermore, it includes some objects of intrinsic interest, like blue stragglers and certain pulsating variables. All the spectra have been uniformly reduced, and all are available online. For dwarfs and giants, the spectra of early-type objects are relatively featureless, dominated by Hydrogen lines around A spectral types. Besides these, the most noticeable photospheric features correspond to water vapor and silicon monoxide in late-type objects and methane and ammonia features at the latest spectral types. Most supergiant spectra in the Atlas present evidence of circumstell...

  10. Neoclassical impurity transport in stellarator geometry

    CERN Document Server

    García-Regaña, J M; Beidler, C D; berg, H Maaß; Helander, P; Turkin, Y

    2012-01-01

    The impurity dynamics in stellarators has become an issue of moderate concern due to the, \\textit{a priori}, inherent tendency of the impurities to accumulate in the core when the neoclassical ambipolar radial electric field points radially inwards (ion root regime). This accumulation can lead to collapse of the plasma due to radiative losses, and thus limit high performance plasma discharges in non-axisymmetric devices. Theoretically, a quantitative description of the neoclassical impurity transport is complicated by the breakdown of the assumption of small $q \\tilde{\\Phi}/T$ for impurities, where $q$ is the electric charge, $T$ the temperature in energy units, and $\\tilde{\\Phi}$ the electrostatic potential variation within the flux surface. The present work describes quantitatively the particle transport of impurities in the frame of local neoclassical theory when $q\\tilde{\\Phi}/T=O(1)$ in the Large Helical Device (LHD) stellarator. %and the Wendelstein 7-X stellarators. The central numerical tool used is t...

  11. Stellar populations -- the next ten years

    CERN Document Server

    Bland-Hawthorn, J

    2007-01-01

    The study of stellar populations is a discipline that is highly dependent on both imaging and spectroscopy. I discuss techniques in different regimes of resolving power: broadband imaging (R~4), intermediate band imaging (R~16, 64), narrowband spectral imaging (R~256, 1024, 4096). In recent years, we have seen major advances in broadband all-sky surveys that are set to continue across optical and IR bands, with the added benefit of the time domain, higher sensitivity, and improved photometric accuracy. Tunable filters and integral field spectrographs are poised to make inroads into intermediate and narrowband imaging studies of stellar populations. Further advances will come from AO-assisted imaging and imaging spectroscopy, although photometric accuracy will be challenging. Integral field spectroscopy will continue to have a major impact on future stellar population studies, extending into the near infrared once the OH suppression problem is finally resolved. A sky rendered dark will allow a host of new idea...

  12. Students Excited by Stellar Discovery

    Science.gov (United States)

    2011-02-01

    In the constellation of Ophiuchus, above the disk of our Milky Way Galaxy, there lurks a stellar corpse spinning 30 times per second -- an exotic star known as a radio pulsar. This object was unknown until it was discovered last week by three high school students. These students are part of the Pulsar Search Collaboratory (PSC) project, run by the National Radio Astronomy Observatory (NRAO) in Green Bank, WV, and West Virginia University (WVU). The pulsar, which may be a rare kind of neutron star called a recycled pulsar, was discovered independently by Virginia students Alexander Snider and Casey Thompson, on January 20, and a day later by Kentucky student Hannah Mabry. "Every day, I told myself, 'I have to find a pulsar. I better find a pulsar before this class ends,'" said Mabry. When she actually made the discovery, she could barely contain her excitement. "I started screaming and jumping up and down." Thompson was similarly expressive. "After three years of searching, I hadn't found a single thing," he said, "but when I did, I threw my hands up in the air and said, 'Yes!'." Snider said, "It actually feels really neat to be the first person to ever see something like that. It's an uplifting feeling." As part of the PSC, the students analyze real data from NRAO's Robert C. Byrd Green Bank Telescope (GBT) to find pulsars. The students' teachers -- Debra Edwards of Sherando High School, Leah Lorton of James River High School, and Jennifer Carter of Rowan County Senior High School -- all introduced the PSC in their classes, and interested students formed teams to continue the work. Even before the discovery, Mabry simply enjoyed the search. "It just feels like you're actually doing something," she said. "It's a good feeling." Once the pulsar candidate was reported to NRAO, Project Director Rachel Rosen took a look and agreed with the young scientists. A followup observing session was scheduled on the GBT. Snider and Mabry traveled to West Virginia to assist in the

  13. Inertial Confinement Fusion Annual Report 1999

    Energy Technology Data Exchange (ETDEWEB)

    Kauffman, R

    2001-07-01

    performed by the ICF Program in FY1999. The report is divided into five sections corresponding to the major areas of program activities. These are sections on (1) ignition target physics experiments theory and modeling, (2) high energy density experimental science, (3) target development, fabrication, and handling, (4) NIF laser development, and (5) optics technology development.

  14. Clementine Star Tracker Stellar Compass: Final report part 1

    Energy Technology Data Exchange (ETDEWEB)

    Priest, R.E.; Kordas, J.F.; Lewis, I.T. [and others

    1995-07-01

    The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth and space were returned from this mission. Two star stracker stellar compasses (star tracker camera + stellar compass software) were included on the spacecraft, serving a primary function of providing angle updates to the guidance and navigation system. These cameras served a secondary function by providing a wide field of view imaging capability for lunar horizon glow and other dark-side imaging data. This 290 g camera using a 576 x 384 focal plane array and a 17 mm entrance pupil, detected and centroided stars as dim and dimmer than 4.5 m{sub v}, providing rms pointing accuracy of better than 100 {mu}rad pitch and yaw and 450 {mu}rad roll. A description of this light-weight, low power star tracker camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission`s primary objective for flight qualifying the sensors for future Department of Defense flights. Documentation generated during the design, analysis, build, test and characterization of the star tracker cameras are presented. Collectively, this documentation represents a small library of information for this camera, and may be used as a framework for producing copy units by commercial enterprises, and therefore satisfies a Department of Defense and Department of Energy goal to transfer technology to industry. However, the considerable knowledge gained from the experience of the individuals involved in the system trades, design, analysis, production, testing and characterization of the star tracker stellar compass is not contained in this documentation.

  15. Stellar Astrophysics for the Local Group

    Science.gov (United States)

    Aparicio, A.; Herrero, A.; Sánchez, F.

    2011-06-01

    1. Fundamentals of stellar evolution theory: understanding the HRD C. Chiosi; 2. Observations of the most luminous stars in local group galaxies P. Massey; 3. Quantitative spectroscopy of the brightest blue supergiant stars in galaxies R. P. Kudritzki; 4. Calibration of the extragalactic distance scale B. F. Madore and W. L. Freedman; 5. Dwarf galaxies G. S. Da Costa; 6. Resolved stellar populations of the luminous galaxies in the local group M. Mateo; 7. Chemical evolution of the ISM in nearby galaxies E. D. Skillman; 8. Populations of massive stars and the interstellar medium C. Leitherer.

  16. Approximate input physics for stellar modelling

    CERN Document Server

    Pols, O R; Eggleton, P P; Han, Z; Pols, O R; Tout, C A; Eggleton, P P; Han, Z

    1995-01-01

    We present a simple and efficient, yet reasonably accurate, equation of state, which at the moderately low temperatures and high densities found in the interiors of stars less massive than the Sun is substantially more accurate than its predecessor by Eggleton, Faulkner & Flannery. Along with the most recently available values in tabular form of opacities, neutrino loss rates, and nuclear reaction rates for a selection of the most important reactions, this provides a convenient package of input physics for stellar modelling. We briefly discuss a few results obtained with the updated stellar evolution code.

  17. The approximate weak inertial manifolds of a class of nonlinear hyperbolic dynamical systems

    Institute of Scientific and Technical Information of China (English)

    赵怡

    1996-01-01

    Some concepts about approximate and semi-approximate weak inertial manifolds are introduced and the existence of global attractor and semi-approximate weak inertial manifolds is obtained for a class of nonlinear hyperbolic dynamical systems by means of some topologically homeomorphic mappings and techniques. Using these results, the existence of approximate weak inertial manifolds is also presented for a kind of nonlinear hyperbolic system arising from relativistic quantum mechanics. The regularization problem is proposed finally.

  18. Novel approaches for improved performance of inertial sensors and integrated navigation systems

    OpenAIRE

    Edwan, Ezzaldeen

    2013-01-01

    Navigation is the science and art that answers the questions of knowing where you are at the current moment and where you will be in the next moment. Modern navigation systems are based mainly on satellite and inertial sensors. Inertial sensor systems are becoming very popular in navigation systems because they are self contained sensors. The goal of this research is to develop novel approaches for improving the performance of inertial sensor systems and their integration algorithms with exte...

  19. Ambitious Survey Spots Stellar Nurseries

    Science.gov (United States)

    2010-08-01

    -dimensional geometry of the Magellanic system. Chris Evans from the VMC team adds: "The VISTA images will allow us to extend our studies beyond the inner regions of the Tarantula into the multitude of smaller stellar nurseries nearby, which also harbour a rich population of young and massive stars. Armed with the new, exquisite infrared images, we will be able to probe the cocoons in which massive stars are still forming today, while also looking at their interaction with older stars in the wider region." The wide-field image shows a host of different objects. The bright area above the centre is the Tarantula Nebula itself, with the RMC 136 cluster of massive stars in its core. To the left is the NGC 2100 star cluster. To the right is the tiny remnant of the supernova SN1987A (eso1032). Below the centre are a series of star-forming regions including NGC 2080 - nicknamed the "Ghost Head Nebula" - and the NGC 2083 star cluster. The VISTA Magellanic Cloud Survey is one of six huge near-infrared surveys of the southern sky that will take up most of the first five years of operations of VISTA. Notes [1] VISTA ― the Visible and Infrared Survey Telescope for Astronomy ― is the newest telescope at ESO's Paranal Observatory in northern Chile. VISTA is a survey telescope working at near-infrared wavelengths and is the world's largest survey telescope. Its large mirror, wide field of view and very sensitive detectors will reveal a completely new view of the southern sky. The telescope is housed on the peak adjacent to the one hosting ESO's Very Large Telescope (VLT) and shares the same exceptional observing conditions. VISTA has a main mirror that is 4.1 m across. In photographic terms it can be thought of as a 67-megapixel digital camera with a 13 000 mm f/3.25 mirror lens. More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries

  20. Evaluation of the Inertial Response of Variable-Speed Wind Turbines Using Advanced Simulation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Scholbrock, Andrew K [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Scholbrock, Andrew K [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-09

    In this paper, we focus on the temporary frequency support effect provided by wind turbine generators (WTGs) through the inertial response. With the implemented inertial control methods, the WTG is capable of increasing its active power output by releasing parts of the stored kinetic energy when the frequency excursion occurs. The active power can be boosted temporarily above the maximum power points, but the rotor speed deceleration follows and an active power output deficiency occurs during the restoration of rotor kinetic energy. In this paper, we evaluate and compare the inertial response induced by two distinct inertial control methods using advanced simulation. In the first stage, the proposed inertial control methods are analyzed in offline simulation. Using an advanced wind turbine simulation program, FAST with TurbSim, the response of the researched wind turbine is comprehensively evaluated under turbulent wind conditions, and the impact on the turbine mechanical components are assessed. In the second stage, the inertial control is deployed on a real 600-kW wind turbine, the three-bladed Controls Advanced Research Turbine, which further verifies the inertial control through a hardware-in-the-loop simulation. Various inertial control methods can be effectively evaluated based on the proposed two-stage simulation platform, which combines the offline simulation and real-time hardware-in-the-loop simulation. The simulation results also provide insights in designing inertial control for WTGs.