Science.gov

Sample records for achieve precise control

  1. Analysis of achievable disturbance attenuation in a precision magnetically-suspended motion control system

    NASA Technical Reports Server (NTRS)

    Kuzin, Alexander V.; Holmes, Michael L.; Behrouzjou, Roxana; Trumper, David L.

    1994-01-01

    The results of the analysis of the achievable disturbance attenuation to get an Angstrom motion control resolution and macroscopic travel in a precision magnetically-suspended motion control system are presented in this paper. Noise sources in the transducers, electronics, and mechanical vibrations are used to develop the control design.

  2. Precision digital control systems

    NASA Astrophysics Data System (ADS)

    Vyskub, V. G.; Rozov, B. S.; Savelev, V. I.

    This book is concerned with the characteristics of digital control systems of great accuracy. A classification of such systems is considered along with aspects of stabilization, programmable control applications, digital tracking systems and servomechanisms, and precision systems for the control of a scanning laser beam. Other topics explored are related to systems of proportional control, linear devices and methods for increasing precision, approaches for further decreasing the response time in the case of high-speed operation, possibilities for the implementation of a logical control law, and methods for the study of precision digital control systems. A description is presented of precision automatic control systems which make use of electronic computers, taking into account the existing possibilities for an employment of computers in automatic control systems, approaches and studies required for including a computer in such control systems, and an analysis of the structure of automatic control systems with computers. Attention is also given to functional blocks in the considered systems.

  3. Instrument Attitude Precision Control

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan

    2004-01-01

    A novel approach is presented in this paper to analyze attitude precision and control for an instrument gimbaled to a spacecraft subject to an internal disturbance caused by a moving component inside the instrument. Nonlinear differential equations of motion for some sample cases are derived and solved analytically to gain insight into the influence of the disturbance on the attitude pointing error. A simple control law is developed to eliminate the instrument pointing error caused by the internal disturbance. Several cases are presented to demonstrate and verify the concept presented in this paper.

  4. Active-member control of precision structures

    NASA Technical Reports Server (NTRS)

    Fanson, J. L.; Blackwood, G. H.; Chu, C. C.

    1989-01-01

    This paper presents the results of closed loop experiments that use piezoelectric active-members to control the flexible motion of a precision truss structure. These experiments are directed toward the development of high performance structural systems as part of the Control/Structure Interaction program at JPL. Order of magnitude reductions in dynamic response are achieved with relatively simple control techniques. The practical implementation of high stiffness, high bandwidth active-members in a precision structure highlights specific issues of importance relating to the modelling and implementation of active-member control.

  5. High bandwidth control of precision motion instrumentation

    NASA Astrophysics Data System (ADS)

    Bristow, Douglas A.; Dong, Jingyan; Alleyne, Andrew G.; Ferreira, Placid; Salapaka, Srinivas

    2008-10-01

    This article presents a high-bandwidth control design suitable for precision motion instrumentation. Iterative learning control (ILC), a feedforward technique that uses previous iterations of the desired trajectory, is used to leverage the repetition that occurs in many tasks, such as raster scanning in microscopy. Two ILC designs are presented. The first design uses the motion system dynamic model to maximize bandwidth. The second design uses a time-varying bandwidth that is particularly useful for nonsmooth trajectories such as raster scanning. Both designs are applied to a multiaxis piezoelectric-actuated flexure system and evaluated on a nonsmooth trajectory. The ILC designs demonstrate significant bandwidth and precision improvements over the feedback controller, and the ability to achieve precision motion control at frequencies higher than multiple system resonances.

  6. Precision Segmented Reflector figure control system architecture

    NASA Technical Reports Server (NTRS)

    Mettler, E.; Eldred, D.; Briggs, C.; Kiceniuk, T.; Agronin, M.

    1989-01-01

    A control system architecture for an actively controlled segmented reflector is described along with a design realization for achieving precision alignment of reflector panels. Performance requirements are derived in part from the Large Deployable Reflector, which is a representative mission, and error allocations are made which consider mirror panel surface errors, position measurement and figure estimation, and position control of both quasi-static and dynamic disturbances. The design uses multiple wavelength interferometric edge sensors and voice coil actuators in conjunction with a hybrid control strategy to correct panel position errors. A unit cell shown to be central to the concept is analyzed. The cell integrates the sensing, actuation, and mechanical functions of a control module together with a reflector panel to form a unitized assembly.

  7. Stellar chemical abundances: in pursuit of the highest achievable precision

    SciTech Connect

    Bedell, Megan; Bean, Jacob L.; Meléndez, Jorge; Leite, Paulo; Asplund, Martin

    2014-11-01

    The achievable level of precision on photospheric abundances of stars is a major limiting factor on investigations of exoplanet host star characteristics, the chemical histories of star clusters, and the evolution of the Milky Way and other galaxies. While model-induced errors can be minimized through the differential analysis of spectrally similar stars, the maximum achievable precision of this technique has been debated. As a test, we derive differential abundances of 19 elements from high-quality asteroid-reflected solar spectra taken using a variety of instruments and conditions. We treat the solar spectra as being from unknown stars and use the resulting differential abundances, which are expected to be zero, as a diagnostic of the error in our measurements. Our results indicate that the relative resolution of the target and reference spectra is a major consideration, with use of different instruments to obtain the two spectra leading to errors up to 0.04 dex. Use of the same instrument at different epochs for the two spectra has a much smaller effect (∼0.007 dex). The asteroid used to obtain the solar standard also has a negligible effect (∼0.006 dex). Assuming that systematic errors from the stellar model atmospheres have been minimized, as in the case of solar twins, we confirm that differential chemical abundances can be obtained at sub-0.01 dex precision with due care in the observations, data reduction, and abundance analysis.

  8. Precision attitude control for tethered satellites

    NASA Technical Reports Server (NTRS)

    Kline-Schoder, Robert J.; Powell, J. D.

    1993-01-01

    Tethered spacecraft are particularly well suited to serve as isolation platforms for space-borne observatories. It has previously been shown that, due to the relatively large tether force, conventional means of performing attitude control for tethered satellites are inefficient for any mission with pointing requirements more stringent than about 1 deg. A particularly effective method of implementing attitude control for tethered satellites is to use the tether tension force to generate control moments by moving the tether attach point relative to the subsatellite center of mass. This paper presents the development of a precision pointing control algorithm for tethered satellites and the simulation of the control system with laboratory hardware. The control algorithm consists of a linear quadratic regulator feedback law and a Kalman filter. The control algorithm has been shown to regulate the vehicle orientation to within 0.60 arcsec rms. This level of precision was achieved only after including a mass center estimator and accurately modeling the effects of the nonlinear attach point motion actuator.

  9. Precision stop control for motors

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor); Montenegro, Justino (Inventor)

    2000-01-01

    An improved stop control system and method are provided for a motor having a drive mechanism in which the motor is coupled to a motor controller that controls the speed and position of the drive mechanism using a first signal indicative of a commanded position of the drive mechanism, a second signal indicative of the actual speed of the drive mechanism and a third signal indicative of the actual position of the drive mechanism. The improved system/method uses a first circuit that receives the first and third signal and generates an error signal indicative of a difference therebetween. A second circuit receives the error signal and compares same with a threshold position error. The result of this comparison is used to selectively supply the second signal (i.e., speed) to the motor controller at least whenever the error signal is less than the threshold position error so that the motor controller can use the second signal in conjunction with the third signal to stop the motor.

  10. How people achieve their amazing temporal precision in interception.

    PubMed

    Brenner, Eli; Smeets, Jeroen B J

    2015-01-01

    People can hit rapidly moving balls with amazing precision. To determine how they manage to do so, we explored how various factors that we could manipulate influenced people's precision when intercepting virtual targets. We found that temporal precision was highest for fast targets that subjects were free to intercept wherever they wished. Temporal precision was much poorer when the point of interception was specified in advance. Examining responses to abrupt perturbations of the target's motion revealed that people adjusted where rather than when they would hit the target if given the choice. A model that combines judging how long it will take to reach the target's path with estimating the target's position at that time from its visually perceived position and velocity could account for the observed precision with reasonable values for all the parameters. The model considers all relevant sources of errors, together with the delays with which the various aspects can be adjusted. Our analysis provides a biologically plausible explanation for how light falling on the eye can guide the hand to intercept a moving ball with such high precision. PMID:25767094

  11. An apparent contradiction: increasing variability to achieve greater precision?

    PubMed

    Rosenblatt, Noah J; Hurt, Christopher P; Latash, Mark L; Grabiner, Mark D

    2014-02-01

    To understand the relationship between variability of foot placement in the frontal plane and stability of gait patterns, we explored how constraining mediolateral foot placement during walking affects the structure of kinematic variance in the lower-limb configuration space during the swing phase of gait. Ten young subjects walked under three conditions: (1) unconstrained (normal walking), (2) constrained (walking overground with visual guides for foot placement to achieve the measured unconstrained step width) and, (3) beam (walking on elevated beams spaced to achieve the measured unconstrained step width). The uncontrolled manifold analysis of the joint configuration variance was used to quantify two variance components, one that did not affect the mediolateral trajectory of the foot in the frontal plane ("good variance") and one that affected this trajectory ("bad variance"). Based on recent studies, we hypothesized that across conditions (1) the index of the synergy stabilizing the mediolateral trajectory of the foot (the normalized difference between the "good variance" and "bad variance") would systematically increase and (2) the changes in the synergy index would be associated with a disproportionate increase in the "good variance." Both hypotheses were confirmed. We conclude that an increase in the "good variance" component of the joint configuration variance may be an effective method of ensuring high stability of gait patterns during conditions requiring increased control of foot placement, particularly if a postural threat is present. Ultimately, designing interventions that encourage a larger amount of "good variance" may be a promising method of improving stability of gait patterns in populations such as older adults and neurological patients. PMID:24162866

  12. Precision controllability of the F-15 airplane

    NASA Technical Reports Server (NTRS)

    Sisk, T. R.; Matheny, N. W.

    1979-01-01

    A flying qualities evaluation conducted on a preproduction F-15 airplane permitted an assessment to be made of its precision controllability in the high subsonic and low transonic flight regime over the allowable angle of attack range. Precision controllability, or gunsight tracking, studies were conducted in windup turn maneuvers with the gunsight in the caged pipper mode and depressed 70 mils. This evaluation showed the F-15 airplane to experience severe buffet and mild-to-moderate wing rock at the higher angles of attack. It showed the F-15 airplane radial tracking precision to vary from approximately 6 to 20 mils over the load factor range tested. Tracking in the presence of wing rock essentially doubled the radial tracking error generated at the lower angles of attack. The stability augmentation system affected the tracking precision of the F-15 airplane more than it did that of previous aircraft studied.

  13. Precision Teaching: Advancing Student Achievement through Daily Drill and Measurement.

    ERIC Educational Resources Information Center

    Rawers, Lois J.

    1983-01-01

    After reviewing the conceptual bases and practical application of precision teaching, this analysis traces its evolution as the Sacajawea Plan, reports on its implementation in central Oregon school districts, and details the costs and procedures of adoption. Developed by Ogden Lindsley from B. F. Skinner's work in operant conditioning and…

  14. GENERATION AND CONTROL OF HIGH PRECISION BEAMS AT LEPTON ACCELERATORS

    SciTech Connect

    Yu-Chiu Chao

    2007-06-25

    Parity violation experiments require precision manipulation of helicity-correlated beam coordinates on target at the nm/nrad-level. Achieving this unprecedented level of control requires a detailed understanding of the particle optics and careful tuning of the beam transport to keep anomalies from compromising the design adiabatic damping. Such efforts are often hindered by machine configuration and instrumentation limitations at the low energy end. A technique has been developed at CEBAF including high precision measurements, Mathematica-based analysis for obtaining corrective solutions, and control hardware/software developments for realizing such level of control at energies up to 5 GeV.

  15. Precision control of high temperature furnaces

    SciTech Connect

    Pollock, G.G.

    1994-12-31

    It is an object of the present invention to provide precision control of high temperature furnaces. It is another object of the present invention to combine the power of two power supplies of greatly differing output capacities in a single furnace. This invention combines two power supplies to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved. Further, this invention comprises a means for high speed measurement of temperature of the process by the method of measuring the amount of current flow in a deliberately induced charged particle current.

  16. Precision controllability of the YF-17 airplane

    NASA Technical Reports Server (NTRS)

    Sisk, T. R.; Mataeny, N. W.

    1980-01-01

    A flying qualities evaluation conducted on the YF-17 airplane permitted assessment of its precision controllability in the transonic flight regime over the allowable angle of attack range. The precision controllability (tailchase tracking) study was conducted in constant-g and windup turn tracking maneuvers with the command augmentation system (CAS) on, automatic maneuver flaps, and the caged pipper gunsight depressed 70 mils. This study showed that the YF-17 airplane tracks essentially as well at 7 g's to 8 g's as earlier fighters did at 4 g's to 5 g's before they encountered wing rock. The pilots considered the YF-17 airplane one of the best tracking airplanes they had flown. Wing rock at the higher angles of attack degraded tracking precision, and lack of control harmony made precision controllability more difficult. The revised automatic maneuver flap schedule incorporated in the airplane at the time of the tests did not appear to be optimum. The largest tracking errors and greatest pilot workload occurred at high normal load factors at low angles of attack. The pilots reported that the high-g maneuvers caused some tunnel vision and that they found it difficult to think clearly after repeated maneuvers.

  17. Precision pointing and control of flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Bantell, M. H., Jr.

    1987-01-01

    The problem and long term objectives for the precision pointing and control of flexible spacecraft are given. The four basic objectives are stated in terms of two principle tasks. Under Task 1, robust low order controllers, improved structural modeling methods for control applications and identification methods for structural dynamics are being developed. Under Task 2, a lab test experiment for verification of control laws and system identification algorithms is being developed. For Task 1, work has focused on robust low order controller design and some initial considerations for structural modeling in control applications. For Task 2, work has focused on experiment design and fabrication, along with sensor selection and initial digital controller implementation. Conclusions are given.

  18. Dynamically Achieved Active Site Precision in Enzyme Catalysis

    PubMed Central

    2015-01-01

    Conspectus The grand challenge in enzymology is to define and understand all of the parameters that contribute to enzymes’ enormous rate accelerations. The property of hydrogen tunneling in enzyme reactions has moved the focus of research away from an exclusive focus on transition state stabilization toward the importance of the motions of the heavy atoms of the protein, a role for reduced barrier width in catalysis, and the sampling of a protein conformational landscape to achieve a family of protein substates that optimize enzyme–substrate interactions and beyond. This Account focuses on a thermophilic alcohol dehydrogenase for which the chemical step of hydride transfer is rate determining across a wide range of experimental conditions. The properties of the chemical coordinate have been probed using kinetic isotope effects, indicating a transition in behavior below 30 °C that distinguishes nonoptimal from optimal C–H activation. Further, the introduction of single site mutants has the impact of either enhancing or eliminating the temperature dependent transition in catalysis. Biophysical probes, which include time dependent hydrogen/deuterium exchange and fluorescent lifetimes and Stokes shifts, have also been pursued. These studies allow the correlation of spatially resolved transitions in protein motions with catalysis. It is now possible to define a long-range network of protein motions in ht-ADH that extends from a dimer interface to the substrate binding domain across to the cofactor binding domain, over a distance of ca. 30 Å. The ongoing challenge to obtaining spatial and temporal resolution of catalysis-linked protein motions is discussed. PMID:25539048

  19. The GBT precision telescope control system

    NASA Astrophysics Data System (ADS)

    Prestage, Richard M.; Constantikes, Kim T.; Balser, Dana S.; Condon, James J.

    2004-10-01

    The NRAO Robert C. Byrd Green Bank Telescope (GBT) is a 100m diameter advanced single dish radio telescope designed for a wide range of astronomical projects with special emphasis on precision imaging. Open-loop adjustments of the active surface, and real-time corrections to pointing and focus on the basis of structural temperatures already allow observations at frequencies up to 50GHz. Our ultimate goal is to extend the observing frequency limit up to 115GHz; this will require a two dimensional tracking error better than 1.3", and an rms surface accuracy better than 210μm. The Precision Telescope Control System project has two main components. One aspect is the continued deployment of appropriate metrology systems, including temperature sensors, inclinometers, laser rangefinders and other devices. An improved control system architecture will harness this measurement capability with the existing servo systems, to deliver the precision operation required. The second aspect is the execution of a series of experiments to identify, understand and correct the residual pointing and surface accuracy errors. These can have multiple causes, many of which depend on variable environmental conditions. A particularly novel approach is to solve simultaneously for gravitational, thermal and wind effects in the development of the telescope pointing and focus tracking models. Our precision temperature sensor system has already allowed us to compensate for thermal gradients in the antenna, which were previously responsible for the largest "non-repeatable" pointing and focus tracking errors. We are currently targetting the effects of wind as the next, currently uncompensated, source of error.

  20. Experimental evaluation of active-member control of precision structures

    NASA Technical Reports Server (NTRS)

    Fanson, James; Blackwood, Gary; Chu, Cheng-Chih

    1989-01-01

    The results of closed loop experiments that use piezoelectric active-members to control the flexible motion of a precision truss structure are described. These experiments are directed toward the development of high-performance structural systems as part of the Control/Structure Interaction (CSI) program at JPL. The focus of CSI activity at JPL is to develop the technology necessary to accurately control both the shape and vibration levels in the precision structures from which proposed large space-based observatories will be built. Structural error budgets for these types of structures will likely be in the sub-micron regime; optical tolerances will be even tighter. In order to achieve system level stability and local positioning at this level, it is generally expected that some form of active control will be required.

  1. Recent results on structural control of an active precision structure

    NASA Technical Reports Server (NTRS)

    Chu, C. C.; Fanson, J. L.; Smith, R. S.

    1991-01-01

    This paper describes recent results in structural control of an active precision truss structure at JPL. The goal is to develop practical control methodology and to apply to active truss structures intended for high precision space-based optics applications. The active structure considered incorporates piezoelectric active members which apply control forces internal to the structure and thereby improve the structure's dimensional stability. Two approaches to structural control system design were investigated. The first approach uses only noncollocated measurements of acceleration at the location of a simulated optical component to achieve structural stabilization. The second approach is essentially the same as the first one except that a viscous damper was used in place of a truss member on the structure to improve the dampings of selected flexible modes. The corresponding experimental closed-loop results are presented in this paper.

  2. Two-DOF precision platform for spacecraft thrust vector control: control strategies and simulations

    NASA Astrophysics Data System (ADS)

    Ma, Kougen; Ghasemi-Nejhad, Mehrdad N.

    2004-07-01

    This paper presents control strategies and simulations of a two-DOF precision platform as an adaptive thruster mount structure with precision positioning and active vibration suppression capabilities for thrust vector control of space satellites. First, the configuration of the two-DOF precision platform is introduced, which is an intelligent tripod with two in-plane rotational degrees of freedom for the top device-plate. Precision positioning of this platform is achieved using active members that extend or contract to tilt the top device-plate where the thruster is mounted. Kinematic analysis of the platform is then presented and followed by two control strategies; namely local control strategy and global control strategy. In the local control strategy, the motion of each active member is controlled locally according to the kinematical feature of the platform and the local sensor information to achieve the desired tilt of the top device-plate. In the global control strategy, the motion of each active member is adjusted according to the system level information from a tilt sensor. Fuzzy logic control is employed and the two control strategies are simulated and compared.

  3. Mechanics of precisely controlled thin film buckling on Elastomeric substrate.

    SciTech Connect

    Sun, Y.; Jiang, H.; Rogers, J.; Huang, Y.; Arizone State Univ.; Beckman Inst.; University of Illinois Urbana-Champaign

    2007-01-01

    Stretchable electronics has many important and emerging applications. Sun et al. [Nature Nanotech. 1, 201 (2006)] recently demonstrated stretchable electronics based on precisely controlled buckle geometries in GaAs and Si nanoribbons on elastomeric substrates. A nonlinear buckling model is presented in this letter to study the mechanics of this type of thin film/substrate system. An analytical solution is obtained for the buckling geometry (wavelength and amplitude) and the maximum strain in buckled thin film. This solution agrees very well with the experiments, and shows explicitly how buckling can significantly reduce the thin film strain to achieve the system stretchability.

  4. Cryogenic precision digital temperature control with peaked frequency response

    NASA Astrophysics Data System (ADS)

    Li, Jie; Lockhart, James M.; Boretsky, Peter

    2004-05-01

    A high precision temperature control system capable of maintaining the temperature of superconducting quantum interference devices (SQUIDs) constant to within 1.0 μK root-mean square over a narrow frequency band was designed and built for use with the superconducting readout system of the Gravity Probe B experiment. The system utilizes an analog ac temperature bridge with a digital proportional-integral control loop which incorporates a peaking filter. A disturbance attenuation factor of 86 or greater over the required frequency band was demonstrated in system tests with the cryogenic hardware, allowing the SQUID system to achieve the required stability. The control system was robust against variations in the thermal characteristics of the cryogenic hardware.

  5. BIOMONITORING TO ACHIEVE CONTROL OF TOXIC EFFLUENTS

    EPA Science Inventory

    This 48 - page Technology Transfer Report provides a case study of how water quality-based toxicity control procedures can be combined with chemical analyses and biological stream surveys to achieve more effective water pollution control. t describes how regulatory agencies used ...

  6. An intelligent control scheme for precise tip-motion control in atomic force microscopy.

    PubMed

    Wang, Yanyan; Hu, Xiaodong; Xu, Linyan

    2016-03-01

    The paper proposes a new intelligent control method to precisely control the tip motion of the atomic force microscopy (AFM). The tip moves up and down at a high rate along the z direction during scanning, requiring the utilization of a rapid feedback controller. The standard proportional-integral (PI) feedback controller is commonly used in commercial AFMs to enable topography measurements. The controller's response performance is determined by the set of the proportional (P) parameter and the integral (I) parameter. However, the two parameters cannot be automatically altered simultaneously according to the scanning speed and the surface topography during continuors scanning, leading to an inaccurate measurement. Thus a new intelligent controller combining the fuzzy controller and the PI controller is put forward in the paper. The new controller automatically selects the most appropriate PI parameters to achieve a fast response rate on basis of the tracking errors. In the experimental setup, the new controller is realized with a digital signal process (DSP) system, implemented in a conventional AFM system. Experiments are carried out by comparing the new method with the standard PI controller. The results demonstrate that the new method is more robust and effective for the precise tip motion control, corresponding to the achievement of a highly qualified image by shortening the response time of the controller. SCANNING 38:93-99, 2016. © 2015 Wiley Periodicals, Inc. PMID:26183109

  7. Precision Motion Control of Linear DC Solenoid Motor

    NASA Astrophysics Data System (ADS)

    Kato, Atsushi; Kubo, Takeharu; Ohnishi, Kouhei

    High speed and high precision control has been required in various cases. Hence, a new linear actuator based on Linear DC Solenoid Motor (LDSM), is developed for that purpose. In addition, we propose a precision motion control for LDSM. LDSM is composed of solenoid stator and moving permanent magnet. It has simple and light structure. Moreover, the solenoid form provides small leakage and generates more power than non-linear motor. Nevertheless, the nonlinear disturbance force such as friction force prevents LDSM from controlling precisely. In this paper, the high gain disturbance observer is applied to LDSM to suppress the force. The observer is able to estimate and compensate the nonlinear disturbance force. It is confirmed that the proposed precision motion control provides LDSM with precise observer control position and force through the experiments.

  8. Achievements of schistosomiasis control in China.

    PubMed

    Yuan, Hongchang; Jiang, Qingwu; Zhao, Genming; He, Na

    2002-01-01

    The control of schistosomiasis has been spectacularly successful in terms of controlling endemicity and severity of the disease during the last 50 years. It can be categorized into two stages. From 1955 through 1980, the transmission-control strategy had been widely and successfully carried out. By the end of 1980, the epidemic of schistosomiasis was successfully circumscribed in certain core regions including areas at the middle and low reaches of the Yangtze River and some mountainous areas in Sichuan and Yunnan provinces, where control of schistosomiasis had been demonstrated to be very difficult to be sustained. Therefore, since 1980, schistosomiasis control in China has been modified to employ a stepwise strategy, based on which morbidity control has been given priorities and if possible transmission control has been pursued. However, since snail-ridden areas remain unchanged so far, reinfections occur frequently. This necessitates a maintenance phase to consolidate the achievements in the control of schistosomiasis. In the mean time, we are challenged with some environmental, social and economical changes in terms of controlling schistosomiasis. Successfully controlling schistosomiasis in China is still a long-term task but will be achieved without doubt along with the economic development and the promotion of living and cultural standard of people. PMID:12426618

  9. The instrument pointing system: Precision attitude control in space

    NASA Astrophysics Data System (ADS)

    Hartmann, Ralf; Woelker, Albrecht

    1990-06-01

    The Spacelab Instrument Pointing System (IPS) is a three axes gimbal system providing pointing and stabilization in the arcsec range to a variety of space experiments with a mass of up to 7000 kg. The IPS demonstrated its control performance during the maiden flight in July 1985, the Spacelab 2 mission on board the Space Shuttle Challenger. The most challenging problem for attitude control in space is the disturbance compensation in the presence of structural flexibilities. Kalman filtering based on optical sensor and gyro measurements as well as flexible mode attenuation and feedforward control were indispensable to achieve high precision. To further enhance the IPS pointing performance and versatility, a new, more autonomous computer and sensor concept has been conceived providing the capacity for a higher degree of automation as well as improved pointing and closed loop tracking control. The autonomy and control capacity of the enhanced IPS establish the basis to accommodate the IPS as long-term available tracking and pointing platform on the International Space Station Freedom (ISF).

  10. High precision high flow range control valve

    DOEpatents

    McCray, J.A.

    1999-07-13

    A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90 [degree] turn. In the preferred embodiment only one of the two fluid passageways contains a 90[degree] turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings. 12 figs.

  11. High precision high flow range control valve

    DOEpatents

    McCray, John A.

    1999-01-01

    A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90.degree. turn. In the preferred embodiment only one of the two fluid passageways contains a 90.degree. turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings.

  12. Precision temperature controller for laser diodes

    NASA Astrophysics Data System (ADS)

    Doermann, Alex; Troxel, Daylin; Jones, Tyler; Erickson, Christopher; Durfee, Dallin

    2010-10-01

    I will present the motivation, theory of operation, and some of the results found with the temperature controller used in Dr. Durfee's lab. I will also present my goal and possible data of the temperature drift as I attempt to make if more effective than a commercial temperature controller already in the lab.

  13. Precision control of multiple quantum cascade lasers for calibration systems

    NASA Astrophysics Data System (ADS)

    Taubman, Matthew S.; Myers, Tanya L.; Pratt, Richard M.; Stahl, Robert D.; Cannon, Bret D.

    2014-01-01

    We present a precision, 1-A, digitally interfaced current controller for quantum cascade lasers, with demonstrated temperature coefficients for continuous and 40-kHz full-depth square-wave modulated operation, of 1-2 ppm/ °C and 15 ppm/ °C, respectively. High precision digital to analog converters (DACs) together with an ultra-precision voltage reference produce highly stable, precision voltages, which are selected by a multiplexer (MUX) chip to set output currents via a linear current regulator. The controller is operated in conjunction with a power multiplexing unit, allowing one of three lasers to be driven by the controller, while ensuring protection of controller and all lasers during operation, standby, and switching. Simple ASCII commands sent over a USB connection to a microprocessor located in the current controller operate both the controller (via the DACs and MUX chip) and the power multiplexer.

  14. Precision control of multiple quantum cascade lasers for calibration systems

    SciTech Connect

    Taubman, Matthew S. Myers, Tanya L.; Pratt, Richard M.; Stahl, Robert D.; Cannon, Bret D.

    2014-01-15

    We present a precision, 1-A, digitally interfaced current controller for quantum cascade lasers, with demonstrated temperature coefficients for continuous and 40-kHz full-depth square-wave modulated operation, of 1–2 ppm/ °C and 15 ppm/ °C, respectively. High precision digital to analog converters (DACs) together with an ultra-precision voltage reference produce highly stable, precision voltages, which are selected by a multiplexer (MUX) chip to set output currents via a linear current regulator. The controller is operated in conjunction with a power multiplexing unit, allowing one of three lasers to be driven by the controller, while ensuring protection of controller and all lasers during operation, standby, and switching. Simple ASCII commands sent over a USB connection to a microprocessor located in the current controller operate both the controller (via the DACs and MUX chip) and the power multiplexer.

  15. Precise carbon control of fabricated stainless steel

    DOEpatents

    Nilsen, R.J.

    1975-12-01

    A process is described for controlling the carbon content of fabricated stainless steel components including the steps of heat treating the component in hydrogen atmospheres of varying dewpoints and carbon potentials.

  16. Precision Pointing Control System (PPCS) star tracker test

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Tests performed on the TRW precision star tracker are described. The unit tested was a two-axis gimballed star tracker designed to provide star LOS data to an accuracy of 1 to 2 sec. The tracker features a unique bearing system and utilizes thermal and mechanical symmetry techniques to achieve high precision which can be demonstrated in a one g environment. The test program included a laboratory evaluation of tracker functional operation, sensitivity, repeatibility, and thermal stability.

  17. Elastic actuator for precise force control

    DOEpatents

    Pratt, Gill A.; Williamson, Matthew M.

    1997-07-22

    The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section.

  18. Elastic actuator for precise force control

    DOEpatents

    Pratt, G.A.; Williamson, M.M.

    1997-07-22

    The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section. 30 figs.

  19. Polyion multilayers with precise surface charge control for antifouling.

    PubMed

    Zhu, Xiaoying; Jańczewski, Dominik; Guo, Shifeng; Lee, Serina Siew Chen; Parra Velandia, Fernando Jose; Teo, Serena Lay-Ming; He, Tao; Puniredd, Sreenivasa Reddy; Vancso, G Julius

    2015-01-14

    We report on a molecular fabrication approach to precisely control surface ζ potentials of polymeric thin layers constructed by electrostatic layer-by-layer (LbL) assembly methods. The protocol established allows us to achieve surface isoelectric points (IEP) in the pH range of 6-10. Poly(acrylic acid) (PAA, a weak polyanion) and poly(diallyldimethylammonium chloride) (PDADMAC, a strong polycation) were chosen to build up the bulk films. The weak polycation polyethylenimine (PEI) was applied as a top layer. A unique feature of this approach is that the chemical composition of the top layer is not affected by the manipulation of the ζ potential of the films. Surface charge tuning is achieved by controlling the degree of ionization of the weak polyelectrolytes at various pH values and subsequent manipulation of the amount of polyelectrolyte deposited in the penultimate and last layers, respectively. Following assembly and characterization, the films were used as candidates for antifouling surfaces. The fouling behavior of barnacle cyprids and bacteria on the LbL films with similar hydrophilicity and roughness but different surface charge densities were studied. We found that more cyprids of Amphibalanus amphitrite settled on the negatively charged LbL film compared to the neutral or positively charged LbL film. In bacterial adhesion tests employing Pseudomonas, Escherichia coli, and Staphylococcus aureus, more bacteria were observed on the positively charged LbL film compared with the neutral and negatively charged LbL films, possibly as a result of the negative potential of the bacterial cell wall. The procedures proposed allow one to adjust surface isoelectric points of LbL architectures to achieve optimal antifouling performance of a given material taking into account specific pH values of the environment and the character of the fouler. PMID:25485625

  20. Toward a metrology for precision-machine-tool control systems

    SciTech Connect

    Pomernacki, C.L.; McCue, H.K.; Newton, L.E.

    1982-07-20

    The difficulty of determining the source of an error in the performance of the control system of a computer numerically controlled (CNC) precision machine tool is discussed and recommendations are made for error isolation using the Machine Control System Meterology Tree. These recommendations refer to types of tests for specific errors and to a possible architecture for a CNC performance tester. It is concluded that there is a need for both a control system metrology and for establishing standards of performance and testing methods for precision machine tool control systems. (LCL)

  1. A new cryostat for precise temperature control

    NASA Astrophysics Data System (ADS)

    Dong, B.; Zhou, G.; Liu, L. Q.; Zhang, X.; Xiong, L. Y.; Li, Q.

    2013-09-01

    Gifford-McMahon (GM) cryocoolers are often used in cryostat as cold sources. It has advantages of simple structure and low operating cost as well as disadvantages of vibration and temperature oscillation, which are fatal for some applications that are very sensitive to temperature stability at low temperature. To solve the problem, a thermal analysis model which is used to simulate heat transfer in the cryostat is built and discussed. According to the analysis results, a cryostat that can provide variable temperature (4-20 K) for the accurate temperature control experiments is designed and manufactured. In this cryostat, a polytetrafluoroethylene (PTFE) sheet is used as a thermal damper to reduce the temperature oscillation, with which, the temperature oscillation of the sample cooling holder is less than 4 mK at the 20 K region.

  2. Pharmaco-informatics: more precise drug therapy from 'multiple model' (MM) adaptive control regimens: evaluation with simulated vancomycin therapy.

    PubMed

    Jelliffe, R W; Bayard, D; Schumitzky, A; Milman, M; Van Guilder, M

    1995-01-01

    A multiple model (MM) stochastic control of dosage regimens permits essentially optimal use of the information contained in either a population pharmacokinetic model or in a MM Bayesian updated parameter set to achieve and maintain selected therapeutic goals with optimal precision. The regimens are visibly more precise than those achieved using mean parameter values. Feedback has now also been incorporated into the MM software. An evaluation of MM adaptive control precision versus control achieved using population mean parameter values is presented using a real population model (Vancomycin). Further feedback control was evaluated, incorporating simulated clinical errors in the preparation and administration of doses. PMID:8591381

  3. Precision Control of Multiple Quantum Cascade Lasers for Calibration Systems

    SciTech Connect

    Taubman, Matthew S.; Myers, Tanya L.; Pratt, Richard M.; Stahl, Robert D.; Cannon, Bret D.

    2014-01-15

    We present a precision, digitally interfaced current controller for quantum cascade lasers, with demonstrated DC and modulated temperature coefficients of 1- 2 ppm/ºC and 15 ppm/ºC respectively. High linearity digital to analog converters (DACs) together with an ultra-precision voltage reference, produce highly stable, precision voltages. These are in turn selected by a low charge-injection multiplexer (MUX) chip, which are then used to set output currents via a linear current regulator. The controller is operated in conjunction with a power multiplexing unit, allowing one of three lasers to be driven by the controller while ensuring protection of controller and all lasers during operation, standby and switching. Simple ASCII commands sent over a USB connection to a microprocessor located in the current controller operate both the controller (via the DACs and MUX chip) and the power multiplexer.

  4. Malaria control: achievements, problems and strategies.

    PubMed

    Nájera, J A

    2001-06-01

    Even if history has not always been the Magistra vitae, Cicero expected it to be, it should provide, as Baas said, a mirror in which to observe and compare the past and present in order to draw therefrom well-grounded conclusions for the future. Based on this belief, this paper aims to provide an overview of the foundations and development of malaria control policies during the XX century. It presents an analysis of the conflicting tendencies which shaped the development of these policies and which appear to have oscillated between calls for frontal attack in an all-out campaign and calls for sustainable gains, even if slow. It discusses the various approaches to the control of malaria, their achievements and their limitations, not only to serve as a background to understand better the foundations of current policies, but also to prevent that simplistic generalisations may again lead to exaggerated expectations and disillusion. The first part of the paper is devoted to the development of malaria control during the first half of the century, characterised by the ups and downs in the reliance on mosquito control as the control measure applicable everywhere. The proliferation of "man-made-malaria", which accompanied the push for economic development in most of the endemic countries, spurred the need for control interventions and, while great successes were obtained in many specific projects, the general campaigns proposed by the enthusiasts of vector control faced increasing difficulties in their practical implementation in the field. Important events, which may be considered representative of this period are, on the campaign approach, the success of Gorgas in the Panama Canal, but also the failure of the Mian Mir project in India; while on the developmental approach, the Italian and Dutch schools of malariology, the Tennessee Valley and the development of malaria sanitation, included the so called species sanitation. The projection of these developments to a global

  5. Indirect precise angular control using four-wave mixing

    SciTech Connect

    Zhang, Wei; Ding, Dong-Sheng; Shi, Bao-Sen Guo, Guang-Can; Jiang, Yun-Kun

    2014-04-28

    Here, we show indirect precise angular control using a four-wave mixing (FWM) process. This was performed with a superposition of light with orbital angular momentum in an M-Type configuration of a hot {sup 85}Rb atomic ensemble. A gear-shaped interference pattern is observed at FWM light with a donut-shaped input signal. The gear could be rotated and is controlled through the change of the polarization of the pump laser. Our experimental results that are based on nonlinear coherent interactions have applications in image processing and precise angular control.

  6. Sequential gas delivery provides precise control of alveolar gas exchange.

    PubMed

    Fisher, Joseph A; Iscoe, Steve; Duffin, James

    2016-05-01

    Of the factors determining blood gases, only alveolar ventilation (V˙A) is amenable to manipulation. However, current physiology text books neither describe how breath-by-breath V˙A can be measured, nor how it can be precisely controlled in spontaneously breathing subjects. And such control must be effected independent of minute ventilation (V˙E) and the pattern of breathing. Control of V˙A requires the deliberate partition of inhaled gas between the alveoli and the anatomical deadspace. This distribution is accomplished by sequential gas delivery (SGD): each breath consists of a chosen volume of 'fresh' gas followed by previously exhaled gas. Control of V˙A through SGD is a simple, inexpensive, yet powerful tool with many applications. Here we describe how to implement SGD, how it precisely controls V˙A, and consequently how it controls arterial blood gases. PMID:26840836

  7. Precise attitude control of the Stanford relativity satellite.

    NASA Technical Reports Server (NTRS)

    Bull, J. S.; Debra, D. B.

    1973-01-01

    A satellite being designed by the Stanford University to measure (with extremely high precision) the effect of General Relativity is described. Specifically, the satellite will measure two relativistic precessions predicted by the theory: the geodetic effect (6.9 arcsec/yr), due solely to motion about the earth, and the motional effect (0.05 arcsec/yr), due to rotation of the earth. The gyro design requirements, including the requirement for precise attitude control and a dynamic model for attitude control synthesis, are discussed. Closed loop simulation of the satellite's natural dynamics on an analog computer is described.

  8. Clinical decision support systems for improving diagnostic accuracy and achieving precision medicine.

    PubMed

    Castaneda, Christian; Nalley, Kip; Mannion, Ciaran; Bhattacharyya, Pritish; Blake, Patrick; Pecora, Andrew; Goy, Andre; Suh, K Stephen

    2015-01-01

    As research laboratories and clinics collaborate to achieve precision medicine, both communities are required to understand mandated electronic health/medical record (EHR/EMR) initiatives that will be fully implemented in all clinics in the United States by 2015. Stakeholders will need to evaluate current record keeping practices and optimize and standardize methodologies to capture nearly all information in digital format. Collaborative efforts from academic and industry sectors are crucial to achieving higher efficacy in patient care while minimizing costs. Currently existing digitized data and information are present in multiple formats and are largely unstructured. In the absence of a universally accepted management system, departments and institutions continue to generate silos of information. As a result, invaluable and newly discovered knowledge is difficult to access. To accelerate biomedical research and reduce healthcare costs, clinical and bioinformatics systems must employ common data elements to create structured annotation forms enabling laboratories and clinics to capture sharable data in real time. Conversion of these datasets to knowable information should be a routine institutionalized process. New scientific knowledge and clinical discoveries can be shared via integrated knowledge environments defined by flexible data models and extensive use of standards, ontologies, vocabularies, and thesauri. In the clinical setting, aggregated knowledge must be displayed in user-friendly formats so that physicians, non-technical laboratory personnel, nurses, data/research coordinators, and end-users can enter data, access information, and understand the output. The effort to connect astronomical numbers of data points, including '-omics'-based molecular data, individual genome sequences, experimental data, patient clinical phenotypes, and follow-up data is a monumental task. Roadblocks to this vision of integration and interoperability include ethical, legal

  9. Enriching the Hierarchical Model of Achievement Motivation: Autonomous and Controlling Reasons Underlying Achievement Goals

    ERIC Educational Resources Information Center

    Michou, Aikaterini; Vansteenkiste, Maarten; Mouratidis, Athanasios; Lens, Willy

    2014-01-01

    Background: The hierarchical model of achievement motivation presumes that achievement goals channel the achievement motives of need for achievement and fear of failure towards motivational outcomes. Yet, less is known whether autonomous and controlling reasons underlying the pursuit of achievement goals can serve as additional pathways between…

  10. High-Precision Twist-Controlled Bilayer and Trilayer Graphene.

    PubMed

    Chen, Xu-Dong; Xin, Wei; Jiang, Wen-Shuai; Liu, Zhi-Bo; Chen, Yongsheng; Tian, Jian-Guo

    2016-04-01

    Twist-controlled bilayer graphene (tBLG) and double-twisted trilayer graphene (DTTG) with high precision are fabricated and their controllable optoelectronic properties are investigated for the first time. The successful fabrication of tBLG and DTTG with designated θ provides an attractive starting point for systematic studies of interlayer coupling in misoriented few-layer graphene systems with well-defined geometry. PMID:26822255

  11. Optochemogenetics (OCG) allows more precise control of genetic engineering in mice with CreER regulators.

    PubMed

    Lu, Xin; Agasti, Sarit S; Vinegoni, Claudio; Waterman, Peter; DePinho, Ronald A; Weissleder, Ralph

    2012-09-19

    New approaches that allow precise spatiotemporal control of gene expression in model organisms at the single cell level are necessary to better dissect the role of specific genes and cell populations in development, disease, and therapy. Here, we describe a new optochemogenetic switch (OCG switch) to control CreER/loxP-mediated recombination via photoactivatable ("caged") tamoxifen analogues in individual cells in cell culture, organoid culture, and in vivo in adult mice. This approach opens opportunities to more fully exploit existing CreER transgenic mouse strains to achieve more precise temporal- and location-specific regulation of genetic events and gene expression. PMID:22917215

  12. Optochemogenetics (OCG) allows more precise control of genetic engineering in mice with CreER regulators

    PubMed Central

    Lu, Xin; Agasti, Sarit S.; Vinegoni, Claudio; Waterman, Peter; DePinho, Ronald A.; Weissleder, Ralph

    2013-01-01

    New approaches that allow precise spatiotemporal control of gene expression in model organisms at the single cell level are necessary to better dissect the role of specific genes and cell populations in development, disease and therapy. Here, we describe a new optochemogenetic switch (OCG switch) to control CreER/loxP-mediated recombination via photoactivatable (“caged”) tamoxifen analogues in individual cells in cell culture, organoid culture and in vivo in adult mice. This approach opens opportunities to more fully exploit existing CreER transgenic mouse strains to achieve more precise temporal- and location-specific regulation of genetic events and gene expression. PMID:22917215

  13. Space Technology 7 Disturbance Reduction System - precision control flight Validation

    NASA Technical Reports Server (NTRS)

    Carmain, Andrew J.; Dunn, Charles; Folkner, William; Hruby, Vlad; Spence, Doug; O'Donnell, James; Markley, Landis; Maghami, Peiman; Hsu, Oscar; Demmons, N.; Roy, T.; Gasdaska, C.; Young, J.; Connolly, W.; McCormick, R.; Gasdaska, C.

    2005-01-01

    The NASA New Millennium Program Space Technology 7 (ST7) project will validate technology for precision spacecraft control. The Disturbance Reduction System (DRS) will be part of the European Space Agency's LISA Pathfinder project. The DRS will control the position of the spacecraft relative to a reference to an accuracy of one nanometer over time scales of several thousand seconds. To perform the control, the spacecraft will use a new colloid thruster technology. The thrusters will operate over the range of 5 to 30 micro-Newtons with precision of 0.1 micro- Newton. The thrust will be generated by using a high electric field to extract charged droplets of a conducting colloid fluid and accelerating them with a precisely adjustable voltage. The control reference will be provided by the European LISA Technology Package, which will include two nearly freefloating test masses. The test mass positions and orientations will be measured using a capacitance bridge. The test mass position and attitude will be adjustable using electrostatically applied forces and torques. The DRS will control the spacecraft position with respect to one test mass while minimizing disturbances on the second test mass. The dynamic control system will cover eighteen degrees of freedom: six for each of the test masses and six for the spacecraft. After launch in late 2009 to a low Earth orbit, the LISA Pathfinder spacecraft will be maneuvered to a halo orbit about the Earth-Sun L1 Lagrange point for operations.

  14. Sliding mode control of magnetic suspensions for precision pointing and tracking applications

    NASA Technical Reports Server (NTRS)

    Misovec, Kathleen M.; Flynn, Frederick J.; Johnson, Bruce G.; Hedrick, J. Karl

    1991-01-01

    A recently developed nonlinear control method, sliding mode control, is examined as a means of advancing the achievable performance of space-based precision pointing and tracking systems that use nonlinear magnetic actuators. Analytic results indicate that sliding mode control improves performance compared to linear control approaches. In order to realize these performance improvements, precise knowledge of the plant is required. Additionally, the interaction of an estimating scheme and the sliding mode controller has not been fully examined in the literature. Estimation schemes were designed for use with this sliding mode controller that do not seriously degrade system performance. The authors designed and built a laboratory testbed to determine the feasibility of utilizing sliding mode control in these types of applications. Using this testbed, experimental verification of the authors' analyses is ongoing.

  15. Ground control requirements for precision processing of ERTS images

    USGS Publications Warehouse

    Burger, Thomas C.

    1973-01-01

    With the successful flight of the ERTS-1 satellite, orbital height images are available for precision processing into products such as 1:1,000,000-scale photomaps and enlargements up to 1:250,000 scale. In order to maintain positional error below 100 meters, control points for the precision processing must be carefully selected, clearly definitive on photos in both X and Y. Coordinates of selected control points measured on existing ½ and 15-minute standard maps provide sufficient accuracy for any space imaging system thus far defined. This procedure references the points to accepted horizontal and vertical datums. Maps as small as 1:250,000 scale can be used as source material for coordinates, but to maintain the desired accuracy, maps of 1:100,000 and larger scale should be used when available.

  16. The Longitudinal Effects of Achievement Goals and Perceived Control on University Student Achievement

    ERIC Educational Resources Information Center

    Daniels, Lia M.; Perry, Raymond P.; Stupnisky, Robert H.; Stewart, Tara L.; Newall, Nancy E. G.; Clifton, Rodney A.

    2014-01-01

    In the area of achievement motivation, students' beliefs pertaining to achievement goals and perceived control have separately guided a large amount theoretical and empirical research. However, limited research has considered the simultaneous effects of goals and control on achievement. The purpose of this study was to examine primary and…

  17. Measuring devices for precision manufacturing and quality control

    NASA Astrophysics Data System (ADS)

    Wilhelm, J.; Jacoby, H. D.; Preuss, H. J.

    1980-12-01

    Various miniaturized and low cost transducers were developed for different applications in metrology, precision manufacturing and fabrication control. They comprise: (1) photoelectric linear transducer with micron step pression; (2) incremental and coded transducers; (3) concave mirror x-y transducer; (4) correlation systems for linear and speed measurements; (5) high resolution angle transducers; and (6) correlation optical sensor for distance measurement. Operation principles are explained and several applications are illustrated. Some of the devices are already available.

  18. Precision Integrated Power and Attitude Control System (IPACS) in the Presence of Dynamic Uncertainty

    NASA Astrophysics Data System (ADS)

    Kim, D.; MacKunis, W.; Fitz-Coy, N.; Dixon, W. E.

    2011-01-01

    An adaptive robust integrated power and attitude control system (IPACS) is presented for a variable speed control moment gyroscope (VSCMG)-actuated satellite. The developed IPACS method is capable of achieving precision attitude control while simultaneously achieving asymptotic power tracking for a rigid-body satellite in the presence of uncertain friction in the VSCMG gimbals and wheels. In addition, the developed controller compensates for the effects of uncertain, time-varying satellite inertia properties. Some challenges encountered in the control design are that the control input is premultiplied by a nonsquare, time-varying, nonlinear, uncertain matrix and is embedded in a discontinuous nonlinear. Globally uniformly ultimately bounded attitude tracking and asymptotic power tracking results are proven via Lyapunov stability analyses, and simulation results are provided to demonstrate the performance of the controller.

  19. Flight evaluations of several hover control and display combinations for precise blind vertical landings

    NASA Technical Reports Server (NTRS)

    Schroeder, J. A.; Merrick, V. K.

    1990-01-01

    Several control and display concepts were evaluated on a variable-stability helicopter prior to future evaluations on a modified Harrier. The control and display concepts had been developed to enable precise hover maneuvers, station keeping, and vertical landings in simulated zero-visibility conditions and had been evaluated extensively in previous piloted simulations. Flight evaluations early in the program revealed several inadequacies in the display drive laws that were later corrected using an alternative design approach that integrated the control and display characteristics with the desired guidance law. While hooded, three pilots performed landing-pad captures followed by vertical landings with attitude-rate, attitude, and translation-velocity-command control systems. The latter control system incorporated a modified version of state-rate-feedback implicit-model following. Precise landing within 2 ft of the desired touchdown point were achieved.

  20. Ground control requirements for precision processing of ERTS images

    USGS Publications Warehouse

    Burger, Thomas C.

    1972-01-01

    When the first Earth Resources Technology Satellite (ERTS-A) flies in 1972, NASA expects to receive and bulk-process 9,000 images a week. From this deluge of images, a few will be selected for precision processing; that is, about 5 percent will be further treated to improve the geometry of the scene, both in the relative and absolute sense. Control points are required for this processing. This paper describes the control requirements for relating ERTS images to a reference surface of the earth. Enough background on the ERTS-A satellite is included to make the requirements meaningful to the user.

  1. Vibration control for precision manufacturing at Sandia National Laboratories

    NASA Astrophysics Data System (ADS)

    Hinnerichs, Terry; Martinez, David

    Sandia National Laboratories performs R&D in structural dynamics and vibration suppression for precision applications in weapon systems, space, underwater, transportation and civil structures. Over the last decade these efforts have expanded into the areas of active vibration control and 'smart' structures and material systems. In addition, Sandia has focused major resources towards technology to support weapon product development and agile manufacturing capability for defense and industrial applications. This paper will briefly describe the structural dynamics modeling and verification process currently in place at Sandia that supports vibration control and some specific applications of these techniques to manufacturing in the areas of lithography, machine tools and flexible robotics.

  2. Vibration control for precision manufacturing at Sandia National Laboratories

    NASA Astrophysics Data System (ADS)

    Hinnerichs, Terry D.; Martinez, David R.

    1995-05-01

    Sandia National Laboratories performs R&D in structural dynamics and vibration suppression of precision applications in weapon systems, space, underwater, transportation and civil structures. Over the last decade these efforts have expanded into the areas of active vibration control and 'smart' structures and material systems, In addition, major resources have been focused towards technology to support weapon product development and agile manufacturing capability for defense and industrial applications. This paper will briefly describe the structural dynamics modeling and verification process that supports vibration control and some specific applications of these techniques to manufacturing in the areas of lithography, machine tools and flexible robotics.

  3. Vibration control for precision manufacturing at Sandia National Laboratories

    SciTech Connect

    Hinnerichs, T.; Martinez, D.

    1995-04-01

    Sandia National Laboratories performs R and D in structural dynamics and vibration suppression for precision applications in weapon systems, space, underwater, transportation and civil structures. Over the last decade these efforts have expanded into the areas of active vibration control and ``smart`` structures and material systems. In addition, Sandia has focused major resources towards technology to support weapon product development and agile manufacturing capability for defense and industrial applications. This paper will briefly describe the structural dynamics modeling and verification process currently in place at Sandia that supports vibration control and some specific applications of these techniques to manufacturing in the areas of lithography, machine tools and flexible robotics.

  4. Control architectures of galvanometer-based scanners for an increased precision and a faster response

    NASA Astrophysics Data System (ADS)

    Mnerie, Corina; Preitl, Stefan; Duma, Virgil-Florin

    2014-01-01

    High-end biomedical applications, such as Optical Coherence Tomography (OCT) or Confocal Microscopy (CM) require both precision and speed. The latter is essential in OCT by example to achieve in vivo, real time imaging - with video rate imaging capability. An essential element of this effort to achieve such speeds in OCT by example is the optomechatronic system used for lateral scanning. It usually consists of a dual axis double galvanometer-based scanner (GS). However, GSs are used in a larger variety of applications in biomedical imaging - not only in lateral scanning. Due to the importance of the topic, we have approached different aspects of GSs technology, including scanning and control functions, duty cycle optimization, and minimization of artifacts. The paper proposes a Model-based Predictive Control (MPC) structure for driving the GSs in order to achieve either an improved precision or a higher speed. The predictive control solution was tested for different types of input signals. Reasons for choosing the objective function and the predictive horizons are discussed. The GS was characterized by a second order mathematical model (MM), with the values of the parameters identified experimentally. Simulations were carried out using Matlab Simulink. The control results achieved are compared with the Proportional Integrative Derivative controller with Lags (PID-L1). The conclusions support the proposed control solution and its implementation in applications.

  5. Closed loop high precision position control system with optical scale

    NASA Astrophysics Data System (ADS)

    Ge, Cheng-liang; Liao, Yuan; He, Zhong-wu; Luo, Zhong-xiang; Huang, Zhi-wei; Wan, Min; Hu, Xiao-yang; Fan, Guo-bin; Liang, Zheng

    2008-03-01

    With the developments of science of art, there are more and more demands on the high resolution control of position of object to be controlled, such as lathe, product line, elements in the optical resonant cavity, telescope, and so on. As one device with high resolution, the optical scale has more and more utility within the industrial and civil applications. With one optical scale and small DC servo motor, one closed loop high resolution position control system is constructed. This apparatus is used to control the position of the elements of optical system. The optical scale is attached on the object or reference guide way. The object position is sampled by a readhead of non-contact optical encoder. Control system processes the position information and control the position of object through the motion control of servo DC motor. The DC motor is controlled by one controller which is connected to an industrial computer. And the micro frictionless slide table does support the smooth motion of object to be controlled. The control algorithm of system is PID (Proportional-Integral-Differential) methods. The PID control methods have well ROBUST. The needed data to control are position, velocity and acceleration of the object. These three parameters correspond to the PID characters respectively. After the accomplishments of hardware, GUI (Graphical user interface), that is, the software of control system is also programmed. The whole system is assembled by specialized worker. Through calibration experiments, the coefficients of PID are obtained respectively. And then the precision of position control of the system is about 0.1μm.

  6. Precision Attitude Control for the BETTII Balloon-Borne Interferometer

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.; Fixsen, Dale J.; Rinehart. Stephen

    2012-01-01

    The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-meter baseline far-infrared interferometer to fly on a high altitude balloon. Operating at wavelengths of 30-90 microns, BETTII will obtain spatial and spectral information on science targets at angular resolutions down to less than half an arcsecond, a capability unmatched by other far-infrared facilities. This requires attitude control at a level ofless than a tenth of an arcsecond, a great challenge for a lightweight balloon-borne system. We have designed a precision attitude determination system to provide gondola attitude knowledge at a level of 2 milliarcseconds at rates up to 100Hz, with accurate absolute attitude determination at the half arcsecond level at rates of up to 10Hz. A mUlti-stage control system involving rigid body motion and tip-tilt-piston correction provides precision pointing stability to the level required for the far-infrared instrument to perform its spatial/spectral interferometry in an open-loop control. We present key aspects of the design of the attitude determination and control and its development status.

  7. Variable conductance heat pipe technology for precise temperature control of the NASA/DDLT transmitter

    NASA Technical Reports Server (NTRS)

    Vanevenhoven, D. E.; Antoniak, D.

    1989-01-01

    The application of variable conductance heat pipe technology for achieving precise temperature control to + or - 0.1 C for a space-based laser diode transmitter is described. Heat pipe theory of operation and test data are presented along with a discussion of its applicability for NASA's Direct Detection Laser Transceiver (DDLT) program. This design for the DDLT transmitter features a reduction in space radiator size and up to 42 percent reduction in prime power requirements.

  8. Precision robotic control of agricultural vehicles on realistic farm trajectories

    NASA Astrophysics Data System (ADS)

    Bell, Thomas

    High-precision "autofarming", or precise agricultural vehicle guidance, is rapidly becoming a reality thanks to increasing computing power and carrier-phase differential GPS ("CPDGPS") position and attitude sensors. Realistic farm trajectories will include not only rows but also arcs created by smoothly joining rows or path-planning algorithms, spirals for farming center-pivot irrigated fields, and curved trajectories dictated by nonlinear field boundaries. In addition, fields are often sloped, and accurate control may be required either on linear trajectories or on curved contours. A three-dimensional vehicle model which adapts to changing vehicle and ground conditions was created, and a low-order model for controller synthesis was extracted based on nominal conditions. The model was extended to include a towed implement. Experimentation showed that an extended Kalman filter could identify the vehicle's state in real-time. An approximation was derived for the additional positional uncertainty introduced by the noisy "lever-arm correction" necessary to translate the GPS position measurement at the roof antenna to the vehicle's control point on the ground; this approximation was then used to support the assertion that attitude measurement accuracy was as important to control point position measurement as the original position measurement accuracy at the GPS antenna. The low-order vehicle control model was transformed to polar coordinates for control on arcs and spirals. Experimental data showed that the tractor's control, point tracked an arc to within a -0.3 cm mean and a 3.4 cm standard deviation and a spiral to within a -0.2 cm mean and a 5.3 cm standard deviation. Cubic splines were used to describe curve trajectories, and a general expression for the time-rate-of-change of curve-related parameters was derived. Four vehicle control algorithms were derived for curve tracking: linear local-error control based on linearizing the vehicle about the curve's radius of

  9. A mathematical basis for the design and design optimization of adaptive trusses in precision control

    NASA Technical Reports Server (NTRS)

    Das, S. K.; Utku, S.; Chen, G.-S.; Wada, B. K.

    1991-01-01

    A mathematical basis for the optimal design of adaptive trusses to be used in supporting precision equipment is provided. The general theory of adaptive structures is introduced, and the global optimization problem of placing a limited number, q, of actuators, so as to maximally achieve precision control and provide prestress, is stated. Two serialized optimization problems, namely, optimal actuator placement for prestress and optimal actuator placement for precision control, are addressed. In the case of prestressing, the computation of a 'desired' prestress is discussed, the interaction between actuators and redundants in conveying the prestress is shown in its mathematical form, and a methodology for arriving at the optimal placement of actuators and additional redundants is discussed. With regard to precision control, an optimal placement scheme (for q actuators) for maximum 'authority' over the precision points is suggested. The results of the two serialized optimization problems are combined to give a suboptimal solution to the global optimization problem. A method for improving this suboptimal actuator placement scheme by iteration is presented.

  10. Precision attitude control of the Gravity Probe B satellite

    NASA Astrophysics Data System (ADS)

    Conklin, J. W.; Adams, M.; Bencze, W. J.; DeBra, D. B.; Green, G.; Herman, L.; Holmes, T.; Muhlfelder, B.; Parkinson, B. W.; Silbergleit, A. S.; Kirschenbaum, J.

    2015-11-01

    The Gravity Probe B satellite used ultra-precise gyroscopes in low Earth orbit to compare the orientation of the local inertial reference frame with that of distant space in order to test predictions of general relativity. The experiment required that the Gravity Probe B spacecraft have milliarcsecond-level attitude knowledge for the science measurement, and milliarcsecond-level control to minimize classical torques acting on the science gyroscopes. The primary sensor was a custom Cassegrainian telescope, which measured the pitch and yaw angles of the experiment package with respect to a guide star. The spacecraft rolled uniformly about the direction to the guide star, and the roll angle was measured by star trackers. Attitude control was performed with sixteen proportional thrusters that used boil-off from the experiment’s liquid Helium cryogen as propellant. This paper summarizes the attitude control system’s design and on-orbit performance.

  11. A Method for Precision Closed-Loop Irrigation Using a Modified PID Control Algorithm

    NASA Astrophysics Data System (ADS)

    Goodchild, Martin; Kühn, Karl; Jenkins, Malcolm; Burek, Kazimierz; Dutton, Andrew

    2016-04-01

    The benefits of closed-loop irrigation control have been demonstrated in grower trials which show the potential for improved crop yields and resource usage. Managing water use by controlling irrigation in response to soil moisture changes to meet crop water demands is a popular approach but requires knowledge of closed-loop control practice. In theory, to obtain precise closed-loop control of a system it is necessary to characterise every component in the control loop to derive the appropriate controller parameters, i.e. proportional, integral & derivative (PID) parameters in a classic PID controller. In practice this is often difficult to achieve. Empirical methods are employed to estimate the PID parameters by observing how the system performs under open-loop conditions. In this paper we present a modified PID controller, with a constrained integral function, that delivers excellent regulation of soil moisture by supplying the appropriate amount of water to meet the needs of the plant during the diurnal cycle. Furthermore, the modified PID controller responds quickly to changes in environmental conditions, including rainfall events which can result in: controller windup, under-watering and plant stress conditions. The experimental work successfully demonstrates the functionality of a constrained integral PID controller that delivers robust and precise irrigation control. Coir substrate strawberry growing trial data is also presented illustrating soil moisture control and the ability to match water deliver to solar radiation.

  12. Precision electronic speed controller for an alternating-current

    DOEpatents

    Bolie, Victor W.

    1988-01-01

    A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for and is particularly suitable for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. In the preferred embodiment, the motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of readonly memories, and a pair of digital-to-analog converters.

  13. Estimates of Savings Achievable from Irrigation Controller

    SciTech Connect

    Williams, Alison; Fuchs, Heidi; Whitehead, Camilla Dunham

    2014-03-28

    This paper performs a literature review and meta-analysis of water savings from several types of advanced irrigation controllers: rain sensors (RS), weather-based irrigation controllers (WBIC), and soil moisture sensors (SMS).The purpose of this work is to derive average water savings per controller type, based to the extent possible on all available data. After a preliminary data scrubbing, we utilized a series of analytical filters to develop our best estimate of average savings. We applied filters to remove data that might bias the sample such as data self-reported by manufacturers, data resulting from studies focusing on high-water users, or data presented in a non-comparable format such as based on total household water use instead of outdoor water use. Because the resulting number of studies was too small to be statistically significant when broken down by controller type, this paper represents a survey and synthesis of available data rather than a definitive statement regarding whether the estimated water savings are representative.

  14. Precision Control Module For UV Laser 3D Micromachining

    NASA Astrophysics Data System (ADS)

    Wu, Wen-Hong; Hung, Min-Wei; Chang, Chun-Li

    2011-01-01

    UV laser has been widely used in various micromachining such as micro-scribing or patterning processing. At present, most of the semiconductors, LEDs, photovoltaic solar panels and touch panels industries need the UV laser processing system. However, most of the UV laser processing applications in the industries utilize two dimensional (2D) plane processing. And there are tremendous business opportunities that can be developed, such as three dimensional (3D) structures of micro-electromechanical (MEMS) sensor or the precision depth control of indium tin oxide (ITO) thin films edge insulation in touch panels. This research aims to develop a UV laser 3D micromachining module that can create the novel applications for industries. By special designed beam expender in optical system, the focal point of UV laser can be adjusted quickly and accurately through the optical path control lens of laser beam expender optical system. Furthermore, the integrated software for galvanometric scanner and focal point adjustment mechanism is developed as well, so as to carry out the precise 3D microstructure machining.

  15. Vibration control for precision manufacturing using piezoelectric actuators

    SciTech Connect

    Martinez, D.R.; Hinnerichs, T.D.; Redmond, J.M.

    1995-12-31

    Piezoelectric actuators provide high frequency, force, and stiffness capabilities along with reasonable Stroke limits, all of which can be used to increase performance levels in precision manufacturing systems. This paper describes two examples of embedding piezoelectric actuators in structural components for vibration control. One example involves suppressing the self excited chatter phenomenon in the metal cutting process of a milling machine and the other involves damping vibrations induced by rigid body stepping of a photolithography platen. Finite element modeling and analyses are essential for locating and sizing the actuators and permit further simulation studies of the response of the dynamic system. Experimental results are given for embedding piezoelectric actuators in a cantilevered bar configuration, which was used as a surrogate machine tool structure. These results are incorporated into a previously developed milling process simulation and the effect of the control on the cutting process stability diagram is quantified. Experimental results are also given for embedding three piezoelectric actuators in a surrogate photolithography platen to suppress vibrations. These results demonstrate the potential benefit that can be realized by applying advances from the field of adaptive structures to problems in precision manufacturing.

  16. Optimal control of precision paraboloidal shell structronic systems

    NASA Astrophysics Data System (ADS)

    Tzou, H. S.; Ding, J. H.

    2004-09-01

    Paraboloidal shells of revolution are commonly used in advanced aerospace, civil and telecommunication structures, e.g., antennas, reflectors, mirrors, rocket fairings, nozzles, solar collectors, dome structures, etc. A structronic shell system is defined as an elastic shell embedded, bonded or laminated with distributed piezoelectric sensors and actuators and it is governed by either in situ or external control electronics. A closed-loop control system of paraboloidal shell structronic system consists of distributed sensors/actuators and controller coupled with an elastic paraboloidal shell. State equation for the paraboloidal shell structronic system is derived and optimal linear quadratic state feedback control is implemented, such that the "best" shell control performance with the least control cost can be achieved. The gain matrix is estimated based on minimizing a performance criterion function. Optimal control effects are compared with controlled responses with other non-optimal control parameters. Control effects of identical-sized sensor/actuator patches at different locations are studied and compared. Modal control effects for different natural modes are also investigated.

  17. In-Process And Post-Process Measurement And Control In Precision Machining

    NASA Astrophysics Data System (ADS)

    McKeown, P. A.

    1983-08-01

    For cost effective control of quality, dimensional size and profile in precision machining, closed loop error feed-back techniques are essential. In other words, maximum efficiency of quality control occurs when the highest speed of response is achieved at the closest possible point of application to the manufacturing process. Optical displacement measuring transducers (grating and CW laser based), coupled with high precision and hiyh response closed loop servo systems under microprocessor control, will be described in the precision machining of high precision engineering components such as cam rings, camshafts, gears and non-conventional optical components. The principles of on-line error compensation techniques will be described in relation to the diamond machining of X-ray telescope mirrors and 3D coordinate measuring machines. The application of laser scanning to the automatic inspection of automotive cylinder bores will also be briefly described, showing how the high costs of visual inspection by human operators can be greatly reduced whilst improving consistency of quality control in detecting of single and cluster surface defects in i.c. engine cylinders.

  18. Ultra-precise holographic beam shaping for microscopic quantum control.

    PubMed

    Zupancic, Philip; Preiss, Philipp M; Ma, Ruichao; Lukin, Alexander; Eric Tai, M; Rispoli, Matthew; Islam, Rajibul; Greiner, Markus

    2016-06-27

    High-resolution addressing of individual ultracold atoms, trapped ions or solid state emitters allows for exquisite control in quantum optics experiments. This becomes possible through large aperture magnifying optics that project microscopic light patterns with diffraction limited performance. We use programmable amplitude holograms generated on a digital micromirror device to create arbitrary microscopic beam shapes with full phase and amplitude control. The system self-corrects for aberrations of up to several λ and reduces them to λ/50, leading to light patterns with a precision on the 10-4 level. We demonstrate aberration-compensated beam shaping in an optical lattice experiment and perform single-site addressing in a quantum gas microscope for 87Rb. PMID:27410551

  19. Ultra-precise holographic beam shaping for microscopic quantum control

    NASA Astrophysics Data System (ADS)

    Zupancic, Philip; Preiss, Philipp M.; Ma, Ruichao; Lukin, Alexander; Eric Tai, M.; Rispoli, Matthew; Islam, Rajibul; Greiner, Markus

    2016-06-01

    High-resolution addressing of individual ultracold atoms, trapped ions or solid state emitters allows for exquisite control in quantum optics experiments. This becomes possible through large aperture magnifying optics that project microscopic light patterns with diffraction limited performance. We use programmable amplitude holograms generated on a digital micromirror device to create arbitrary microscopic beam shapes with full phase and amplitude control. The system self-corrects for aberrations of up to several $\\lambda$ and reduces them to $\\lambda/50$, leading to light patterns with a precision on the $10^{-4}$ level. We demonstrate aberration-compensated beam shaping in an optical lattice experiment and perform single-site addressing in a quantum gas microscope for $^{87}$Rb.

  20. Extreme Precision Environmental Control for Next Generation Radial Velocity Spectrographs

    NASA Astrophysics Data System (ADS)

    Stefansson, Gudmundur K.; Hearty, Fred; Levi, Eric; Robertson, Paul; Mahadevan, Suvrath; Bender, Chad; Nelson, Matt; Halverson, Samuel

    2015-12-01

    Extreme radial velocity precisions of order 10cm/s will enable the discoveries of Earth-like planets around solar-type stars. Temperature and pressure variations inside a spectrograph can lead to thermomechanical instabilities in the optics and mounts, and refractive index variations in both the optical elements as well as the surrounding air. Together, these variations can easily induce instrumental drifts of several tens to hundreds of meters per second. Enclosing the full optical train in thermally stabilized high-vacuum environments minimizes such errors. In this talk, I will discuss the Environmental Control System (ECS) for the Habitable Zone Planet Finder (HPF) spectrograph: a near infrared (NIR) facility class instrument we will commission at the Hobby Eberly Telescope in 2016. The ECS will maintain the HPF optical bench stable at 180K at the sub milli-Kelvin level on the timescale of days, and at the few milli-Kelvin level over months to years. The entire spectrograph is kept under high-quality vacuum (<10-6 Torr), and environmental temperature fluctuations are compensated for with an actively controlled radiation shield outfitted with custom feedback electronics. High efficiency Multi-Layer Insulation (MLI) blankets, and a passive external thermal enclosure further isolate the optics from ambient perturbations. This environmental control scheme is versatile, suitable to stabilize both next generation NIR, and optical spectrographs. I will show how we are currently testing this control system for use with our design concept of the Extreme Precision Doppler Spectrograph (EPDS), the next generation optical spectrograph for the WIYN 3.5m telescope. Our most recent results from full-scale stability tests will be presented.

  1. Alternate method for achieving temperature control in the -160 to +90 Celcius range

    NASA Technical Reports Server (NTRS)

    Johnson, Kenneth R. (Inventor)

    1995-01-01

    A single-pass method for accurate and precise temperature control in the -160 to +90 C range is discussed. The method exhibited minimal set-point overshoot during temperature transitions. Control to +/-2 C with transitions between set-points of 7 C per minute were achieved. The method uses commercially available temperature controllers and a gaseous nitrogen/liquid nitrogen mixer to dampen the amplitude of cold temperature spikes caused by liquid nitrogen pulsing.

  2. Precision electronic speed controller for an alternating-current motor

    DOEpatents

    Bolie, V.W.

    A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. The motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The speed error signal is generated by a novel vernier-logic circuit which is drift-free and highly sensitive to small speed changes. The phase error is also computed by digital logic, with adjustable sensitivity around a 0 mid-scale value. The drift error signal, generated by long-term counting of the phase error, is used to compensate for any slow changes in the average friction drag on the motor. An auxillary drift-byte status sensor prevents any disruptive overflow or underflow of the drift-error counter. An adjustable clocked-delay unit is inserted between the controller and the source of the reference pulse train to permit phase alignment of the rotor to any desired offset angle. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of read-only memories, and a pair of digital-to-analog converters.

  3. Coherence times of precise depth controlled NV centers in diamond

    NASA Astrophysics Data System (ADS)

    Wang, Junfeng; Zhang, Wenlong; Zhang, Jian; You, Jie; Li, Yan; Guo, Guoping; Feng, Fupan; Song, Xuerui; Lou, Liren; Zhu, Wei; Wang, Guanzhong

    2016-03-01

    We investigated the depth dependence of coherence times of nitrogen-vacancy (NV) centers through precise depth control using oxidative etching at 580 °C in air. By successive nanoscale etching, NV centers could be brought close to the diamond surface step by step, which enabled us to track the evolution of the number of NV centers remaining in the chip and to study the depth dependence of coherence times of NV centers with diamond etching. Our results showed that the coherence times of NV centers declined rapidly with the depth reduction in the last about 22 nm before they finally disappeared, which revealed a critical depth for the influence of a rapid fluctuating surface spin bath. Moreover, by using the slow etching method combined with low-energy nitrogen implantation, NV centers with depths shallower than the initially implanted depths can be generated, which are preferred for detecting external spins with higher sensitivity.

  4. Precise Heater Controller with rf-Biased Josephson Junctions

    NASA Technical Reports Server (NTRS)

    Green, Colin J.; Sergatskov, Dmitri A.; Duncan, R. V.

    2003-01-01

    Paramagnetic susceptibility thermometers used in fundamental physics experiments are capable of measuring temperature changes with a precision of a part in 2 x 10(exp 10). However, heater controllers are only able to control open-loop power dissipation to about a part in 10(exp 5). We used an array of rf-biased Josephson junctions to precisely control the electrical power dissipation in a heater resistor mounted on a thermally isolated cryogenic platform. Theoretically, this method is capable of controlling the electrical power dissipation to better than a part in 10(exp 12). However, this level has not yet been demonstrated experimentally. The experiment consists of a liquid helium cell that also functions as a high-resolution PdMn thermometer, with a heater resistor mounted on it. The cell is thermally connected to a temperature-controlled cooling stage via a weak thermal link. The heater resistor is electrically connected to the array of Josephson junctions using superconducting wire. An rf-biased array of capacitively shunted Josephson junctions drives the voltage across the heater. The quantized voltage across the resistor is Vn = nf(h/2e), where h is Planck's constant, f is the array biasing frequency, e is the charge of an electron, and n is the integer quantum state of the Josephson array. This results in an electrical power dissipation on the cell of Pn = (Vn)(sup 2/R), where R is the heater resistance. The change of the quantum state of the array changes the power dissipated in the heater, which in turn, results in the change of the cell temperature. This temperature change is compared to the expected values based on the known thermal standoff resistance of the cell from the cooling stage. We will present our initial experimental results and discuss future improvements. This work has been funded by the Fundamental Physics Discipline of the Microgravity Science Office of NASA, and supported by a no-cost equipment loan from Sandia National Laboratories.

  5. Precision Pointing Control to and Accurate Target Estimation of a Non-Cooperative Vehicle

    NASA Technical Reports Server (NTRS)

    VanEepoel, John; Thienel, Julie; Sanner, Robert M.

    2006-01-01

    In 2004, NASA began investigating a robotic servicing mission for the Hubble Space Telescope (HST). Such a mission would not only require estimates of the HST attitude and rates in order to achieve capture by the proposed Hubble Robotic Vehicle (HRV), but also precision control to achieve the desired rate and maintain the orientation to successfully dock with HST. To generalize the situation, HST is the target vehicle and HRV is the chaser. This work presents a nonlinear approach for estimating the body rates of a non-cooperative target vehicle, and coupling this estimation to a control scheme. Non-cooperative in this context relates to the target vehicle no longer having the ability to maintain attitude control or transmit attitude knowledge.

  6. Residential Mobility, Inhibitory Control, and Academic Achievement in Preschool

    ERIC Educational Resources Information Center

    Schmitt, Sara A.; Finders, Jennifer K.; McClelland, Megan M.

    2015-01-01

    Research Findings: The present study investigated the direct effects of residential mobility on children's inhibitory control and academic achievement during the preschool year. It also explored fall inhibitory control and academic skills as mediators linking residential mobility and spring achievement. Participants included 359 preschool…

  7. Residential Mobility, Inhibitory Control, and Academic Achievement in Preschool

    ERIC Educational Resources Information Center

    Schmitt, Sara A.; Finders, Jennifer K.; McClelland, Megan M.

    2015-01-01

    The present study investigated the direct effects of residential mobility on children's inhibitory control and academic achievement during the preschool year. It also explored fall inhibitory control and academic skills as mediators linking residential mobility and spring achievement. Participants included 359 preschool children (49% female)…

  8. Longitudinal Effects of Perceived Control on Academic Achievement

    ERIC Educational Resources Information Center

    You, Sukkyung; Hong, Sehee; Ho, Hsiu-Zu

    2011-01-01

    It is well established that perceived control plays an important role in student academic achievement, but little is known about its longitudinal stability, ethnic variation, and developmental effects on subsequent achievement during adolescence. Findings from this study indicated (a) perceived control remains stable during adolescence for each of…

  9. Streamlined design and self reliant hardware for active control of precision space structures

    NASA Technical Reports Server (NTRS)

    Hyland, David C.; King, James A.; Phillips, Douglas J.

    1994-01-01

    Precision space structures may require active vibration control to satisfy critical performance requirements relating to line-of-sight pointing accuracy and the maintenance of precise, internal alignments. In order for vibration control concepts to become operational, it is necessary that their benefits be practically demonstrated in large scale ground-based experiments. A unique opportunity to carry out such demonstrations on a wide variety of experimental testbeds was provided by the NASA Control-Structure Integration (CSI) Guest Investigator (GI) Program. This report surveys the experimental results achieved by the Harris Corporation GI team on both Phases 1 and 2 of the program and provides a detailed description of Phase 2 activities. The Phase 1 results illustrated the effectiveness of active vibration control for space structures and demonstrated a systematic methodology for control design, implementation test. In Phase 2, this methodology was significantly streamlined to yield an on-site, single session design/test capability. Moreover, the Phase 2 research on adaptive neural control techniques made significant progress toward fully automated, self-reliant space structure control systems. As a further thrust toward productized, self-contained vibration control systems, the Harris Phase II activity concluded with experimental demonstration of new vibration isolation hardware suitable for a wide range of space-flight and ground-based commercial applications.The CSI GI Program Phase 1 activity was conducted under contract NASA1-18872, and the Phase 2 activity was conducted under NASA1-19372.

  10. Computer controlled precision optical polishing on the diamond turning machine

    SciTech Connect

    Hannah, P.R.; Day, R.D.; Hatch, D.

    1993-10-01

    This abstract reports the force and wear data required to predict the material removal, or wear, for the Numerical controlled (N/C) polishing program. The program`s aim is to provide the operator of a N/C diamond turning machine or N/C grinding machine with the wear characteristics necessary to achieve uniform material removal. The first phase of the program looks at a rotating polishing wheel, moving from near the center to edge of a rotating glass disc. future phases will look at more complex shapes.

  11. Design of a new high precision computer numerical control

    SciTech Connect

    Sweeney, D.J.; Weinert, G.F.

    1988-06-23

    The purpose of this project is to produce a generic high precision computer numerical controller (CNC) for use on microinch- and sub-microinch-resolution machine tools at the Lawrence Livermore National Laboratory. In order to fully utilize the potential of these machine tools, the CNC must include the ability to use multiple feedback sensors on each machine axis, incorporate corrections for quasistatic geometric errors (such as straightness, and squareness), be able to function over a relatively large range of motion (in excess of 60 inches per axis), and be able to produce motion updates at a rate sufficient to take advantage of the high bandwidth of the servo systems. At present, no commercially available CNC can presently meet all of the resolution, feed rate, and length of travel requirements of these machines. In order to minimize the complexity of the system, and thereby increase its reliability and maintainability, the programming was done in a high level language. The number of processors was kept as small as possible while still maintaining the performance requirements. We also used commercially available hardware in preference to building, in order to increase both reliability and maintainability. Special emphasis was given to making the CNC's operator interface as friendly as possible. We have completed a prototype control. We plan to install and test it in 1988. 4 figs.

  12. Two-dimensional, high flow, precisely controlled monodisperse drop source

    NASA Astrophysics Data System (ADS)

    Dressler, John L.

    1993-03-01

    A versatile acoustically-driven fluid atomizer was designed and operated that creates precise monodisperse sprays by Rayleigh breakup or polydisperse sprays by the acoustic driving of amplitude dependent instabilities. The atomizer forms a cylindrical, conical, or flat (sheet) liquid jet by means of a photofabricated nozzle. The spray pattern and spray volume are altered by changing the nozzle. A piezoelectric driver, constructed to efficiently couple energy to the liquid, modulates the fluid velocity. When operated at low power, the drop generator can produce arrays of monodisperse drops as small as 15 microns in diameter. Operating the piezoelectric driver at high power produces perturbations with sufficient energy to break the liquid jets into drops, with a net increase in surface energy. The resulting drop sizes are influenced by the frequency and amplitude of the driving signal and nozzle size. The spatial distribution of the spray is controlled by the spacing and geometry of the holes in the nozzle plate, the amplitude of the acoustic signal, and the swirl in the fluid manifold. This device is more robust than the typical acoustic drop generator because small drops can be made from large holes, reducing the plugging problem. No air flow is used.

  13. Precision control of eluted activity from a Sr/Rb generator for cardiac positron emission tomography.

    PubMed

    Klein, R; Adler, A; Beanlands, R S; deKemp, R A

    2004-01-01

    A rubidium-82 (/sup 82/Rb) elution system is described for use with clinical positron emission tomography. The system is self-calibrating with 1.4% repeatability, independent of generator activity and elution flow rate. Saline flow is switched between a /sup 82/Sr//sup 82/Rb generator and a bypass line to achieve a constant activity elution of /sup 82/Rb. In the present study, pulse width modulation (PWM) of a solenoid valve is compared to simple threshold control as a means to simulate a proportional valve. A predictive-corrective control algorithm is developed which produces a constant activity elution within the constraints of long feedback delay and short elution time. Accurate constant-activity elutions of 10-70% of the total generator activity were demonstrated using the threshold comparison control. The adaptive-corrective control of the PWM valve provided a substantial improvement in precision of the steady-state output. PMID:17271953

  14. Single Cell Transfection through Precise Microinjection with Quantitatively Controlled Injection Volumes

    PubMed Central

    Chow, Yu Ting; Chen, Shuxun; Wang, Ran; Liu, Chichi; Kong, Chi-wing; Li, Ronald A.; Cheng, Shuk Han; Sun, Dong

    2016-01-01

    Cell transfection is a technique wherein foreign genetic molecules are delivered into cells. To elucidate distinct responses during cell genetic modification, methods to achieve transfection at the single-cell level are of great value. Herein, we developed an automated micropipette-based quantitative microinjection technology that can deliver precise amounts of materials into cells. The developed microinjection system achieved precise single-cell microinjection by pre-patterning cells in an array and controlling the amount of substance delivered based on injection pressure and time. The precision of the proposed injection technique was examined by comparing the fluorescence intensities of fluorescent dye droplets with a standard concentration and water droplets with a known injection amount of the dye in oil. Injection of synthetic modified mRNA (modRNA) encoding green fluorescence proteins or a cocktail of plasmids encoding green and red fluorescence proteins into human foreskin fibroblast cells demonstrated that the resulting green fluorescence intensity or green/red fluorescence intensity ratio were well correlated with the amount of genetic material injected into the cells. Single-cell transfection via the developed microinjection technique will be of particular use in cases where cell transfection is challenging and genetically modified of selected cells are desired. PMID:27067121

  15. Single Cell Transfection through Precise Microinjection with Quantitatively Controlled Injection Volumes.

    PubMed

    Chow, Yu Ting; Chen, Shuxun; Wang, Ran; Liu, Chichi; Kong, Chi-Wing; Li, Ronald A; Cheng, Shuk Han; Sun, Dong

    2016-01-01

    Cell transfection is a technique wherein foreign genetic molecules are delivered into cells. To elucidate distinct responses during cell genetic modification, methods to achieve transfection at the single-cell level are of great value. Herein, we developed an automated micropipette-based quantitative microinjection technology that can deliver precise amounts of materials into cells. The developed microinjection system achieved precise single-cell microinjection by pre-patterning cells in an array and controlling the amount of substance delivered based on injection pressure and time. The precision of the proposed injection technique was examined by comparing the fluorescence intensities of fluorescent dye droplets with a standard concentration and water droplets with a known injection amount of the dye in oil. Injection of synthetic modified mRNA (modRNA) encoding green fluorescence proteins or a cocktail of plasmids encoding green and red fluorescence proteins into human foreskin fibroblast cells demonstrated that the resulting green fluorescence intensity or green/red fluorescence intensity ratio were well correlated with the amount of genetic material injected into the cells. Single-cell transfection via the developed microinjection technique will be of particular use in cases where cell transfection is challenging and genetically modified of selected cells are desired. PMID:27067121

  16. Single Cell Transfection through Precise Microinjection with Quantitatively Controlled Injection Volumes

    NASA Astrophysics Data System (ADS)

    Chow, Yu Ting; Chen, Shuxun; Wang, Ran; Liu, Chichi; Kong, Chi-Wing; Li, Ronald A.; Cheng, Shuk Han; Sun, Dong

    2016-04-01

    Cell transfection is a technique wherein foreign genetic molecules are delivered into cells. To elucidate distinct responses during cell genetic modification, methods to achieve transfection at the single-cell level are of great value. Herein, we developed an automated micropipette-based quantitative microinjection technology that can deliver precise amounts of materials into cells. The developed microinjection system achieved precise single-cell microinjection by pre-patterning cells in an array and controlling the amount of substance delivered based on injection pressure and time. The precision of the proposed injection technique was examined by comparing the fluorescence intensities of fluorescent dye droplets with a standard concentration and water droplets with a known injection amount of the dye in oil. Injection of synthetic modified mRNA (modRNA) encoding green fluorescence proteins or a cocktail of plasmids encoding green and red fluorescence proteins into human foreskin fibroblast cells demonstrated that the resulting green fluorescence intensity or green/red fluorescence intensity ratio were well correlated with the amount of genetic material injected into the cells. Single-cell transfection via the developed microinjection technique will be of particular use in cases where cell transfection is challenging and genetically modified of selected cells are desired.

  17. Precision control of recombinant gene transcription for CHO cell synthetic biology.

    PubMed

    Brown, Adam J; James, David C

    2016-01-01

    The next generation of mammalian cell factories for biopharmaceutical production will be genetically engineered to possess both generic and product-specific manufacturing capabilities that may not exist naturally. Introduction of entirely new combinations of synthetic functions (e.g. novel metabolic or stress-response pathways), and retro-engineering of existing functional cell modules will drive disruptive change in cellular manufacturing performance. However, before we can apply the core concepts underpinning synthetic biology (design, build, test) to CHO cell engineering we must first develop practical and robust enabling technologies. Fundamentally, we will require the ability to precisely control the relative stoichiometry of numerous functional components we simultaneously introduce into the host cell factory. In this review we discuss how this can be achieved by design of engineered promoters that enable concerted control of recombinant gene transcription. We describe the specific mechanisms of transcriptional regulation that affect promoter function during bioproduction processes, and detail the highly-specific promoter design criteria that are required in the context of CHO cell engineering. The relative applicability of diverse promoter development strategies are discussed, including re-engineering of natural sequences, design of synthetic transcription factor-based systems, and construction of synthetic promoters. This review highlights the potential of promoter engineering to achieve precision transcriptional control for CHO cell synthetic biology. PMID:26721629

  18. Pointing Control System for a High Precision Flight Telescope

    SciTech Connect

    BENTLEY,ANTHONY E.; WILCOXEN,JEFFREY LEE

    2000-12-01

    A pointing control system is developed and tested for a flying gimbaled telescope. The two-axis pointing system is capable of sub-microradian pointing stability and high accuracy in the presence of large host vehicle jitter. The telescope also has high agility--it is capable of a 50-degree retarget (in both axes simultaneously) in less than 2 seconds. To achieve the design specifications, high-accuracy, high-resolution, two-speed resolvers were used, resulting in gimbal-angle measurements stable to 1.5 microradians. In addition, on-axis inertial angle displacement sensors were mounted on the telescope to provide host-vehicle jitter cancellation. The inertial angle sensors are accurate to about 100 nanoradians, but do not measure low frequency displacements below 2 Hz. The gimbal command signal includes host-vehicle attitude information, which is band-limited. This provides jitter data below 20 Hz, but includes a variable latency between 15 and 25 milliseconds. One of the most challenging aspects of this design was to combine the inertial-angle-sensor data with the less perfect information in the command signal to achieve maximum jitter reduction. The optimum blending of these two signals, along with the feedback compensation were designed using Quantitative Feedback Theory.

  19. GOCE rapid science orbits: Achieving sub-dm orbit precision with minimal latency

    NASA Astrophysics Data System (ADS)

    van den Ijssel, Jose; Visser, Pieter N. A. M.; van Helleputte, Tom; Bock, Heike

    For the GOCE satellite a Rapid Science Orbit (RSO) chain has been implemented to produce daily orbits with a 1-day latency and an accuracy of around 10 cm, in order to support satellite operations. The RSO will be used as input for external calibration and geodetic preprocessing of the gradiometer data and for quick-look gravity field modeling. The RSO chain provides as a baseline two orbit products, a reduced-dynamic and a kinematic solution. The reduced-dynamic RSO solution is computed using the NASA/GSFC GEODYN s/w package and is based on a triple differenced approach, using ionospheric-free GPS phase measurements along with rapid GPS orbits provided by the International GNSS Service. The kinematic RSO solution is computed using the DLR GHOST s/w package, and is based on a zero differenced approach, using rapid GPS orbits and clocks computed by the Center for Orbit Determination in Europe. An overview of both RSO POD strategies will be presented, together with results obtained using about one year of GOCE data. Special attention will be given to the handling of the clock behaviour of the GOCE GPS receiver, which is not steered to GPS time and can show large drifts of up to 10 msec. In addition, the estimated non-gravitational accelerations resulting from the RSO computations will be compared with the gradiometer common-mode accelerations, during different modes of the drag-free control system.

  20. Study on global control network precision positioning method in visual shape measurement

    NASA Astrophysics Data System (ADS)

    Long, Chang-yu; Zhu, Ji-gui

    2013-08-01

    the three-dimensional coordinates of the control points is not affected by the lens distortion and measurement distance. A large number of experiments were carried out using a high-resolution digital camera, and the experimental results show that the measurement accuracy of this method can reach 0.02mm (3m * 3m range), and the root mean square is about 0.015mm. Consequently we conclude that this method can achieve the precise positioning of the global control network and help to improve the accuracy of large-size visual shape measurement.

  1. Interrelationships of Study Habits and Attitudes, Locus of Control, Motivation Achievement Tendencies and Academic Achievement.

    ERIC Educational Resources Information Center

    Gadzella, Bernadette M.; And Others

    The study investigated (a) relationships between measures on study habits and attitudes, locus of control, achieving tendency, and semester grade-point averages (SGPA), (b) differences between the sexes on the above mentioned variables, and (c) best predictor of SGPA. The subjects were 39 males and 81 females. There were a number of significant…

  2. The Impact of Locus of Control on Language Achievement

    ERIC Educational Resources Information Center

    Nodoushan, Mohammad Ali Salmani

    2012-01-01

    This study hypothesized that students' loci of control affected their language achievement. 198 (N = 198) EFL students took the Rotter's (1966) locus of control test and were classified as locus-internal (ni = 78), and locus-external (ne = 120). They then took their ordinary courses and at the end of the semester, they were given their exams.…

  3. Designer Hydrogels for Precision Control of Oxygen Tension and Mechanical Properties

    PubMed Central

    Blatchley, Michael; Park, Kyung Min; Gerecht, Sharon

    2015-01-01

    Oxygen levels and mechanical properties provide vital cues to regulate myriad cellular functions and stem cell fate decisions. Here, we present a hybrid hydrogel system in which we can control independently oxygen levels and mechanical properties. We designed, synthesized and analyzed a hybrid hydrogel system comprised of two polymer backbones, gelatin and dextran. Both polymers were crosslinked via a laccase-mediated, oxygen consuming reaction. By specifically controlling the concentration of phenolic molecules available to react in our hydrogel, we could precisely control the time in which the hydrogel remained hypoxic (TH). We were able to achieve a range of TH from the order of minutes to greater than 10 hours. Additionally, by incorporating a secondary crosslinker, transglutaminase, mechanical properties could be adjusted in a user-defined fashion, with dynamic elastic modulus (G′) values ranging from <20 Pa to >1 kPa. Importantly, oxygen levels and substrate mechanical properties could be individually tuned and decoupled in our hybrid hydrogels, while retaining the potential to study possible synergistic effects between the two parameters. By precisely controlling oxygen tension and mechanical properties, we expect that research utilizing the new hybrid hydrogels will enhance our understanding of the complex 3D cellular processes mediated by each parameter individually and may also hold clinical interest as acellular therapies. PMID:26693017

  4. Computer-controlled high-precision Michelson wavemeter

    NASA Astrophysics Data System (ADS)

    Pedregosa-Gutierrez, J.; Guyomarc'h, D.; Vedel, M.; Champenois, C.; Knoop, M.

    2014-09-01

    The Michelson wavemeter is a popular instrument in many experiments where the high-precision measurement of a cw laser wavelength is required. In this paper, we describe a simple and inexpensive way to obtain high-precision measurements with this classical physicist's tool. We exploit the time stamp provided by the high-frequency clock present in modern data acquisition cards to measure the fractional uncertainty of the interference signal. The resulting relative uncertainty value for our current set-up is of the order of 10-8 and can be potentially improved by a factor of 100.

  5. Purpose plus: supporting youth purpose, control, and academic achievement.

    PubMed

    Pizzolato, Jane Elizabeth; Brown, Elizabeth Levine; Kanny, Mary Allison

    2011-01-01

    Research in the past decade suggests that a persistent achievement gap between students from low-income minority backgrounds and higher-income white backgrounds may be rooted in theories of student motivation and youth purpose. Yet limited research exists regarding the role of purpose on positive youth development as it pertains to academic achievement. Using a sample of 209 high school students, this study examines the effectiveness of an intervention designed to promote purpose development and internal control over academic success in high school students from a low-socioeconomic-status community. Findings reveal that a short-term intervention was effective in significantly increasing internal control over academic success and purpose in life for students participating in the intervention group. In addition, analysis of academic achievement for students who experienced positive gains in internal control and purpose demonstrates significant gains in academic achievement as measured by grade point average. Implications are made for further study of internal control and life purpose as a means of academic intervention in the effort to address the achievement gap. PMID:22275280

  6. Selective assemblies of giant tetrahedra via precisely controlled positional interactions

    NASA Astrophysics Data System (ADS)

    Huang, Mingjun; Hsu, Chih-Hao; Wang, Jing; Mei, Shan; Dong, Xuehui; Li, Yiwen; Li, Mingxuan; Liu, Hao; Zhang, Wei; Aida, Takuzo; Zhang, Wen-Bin; Yue, Kan; Cheng, Stephen Z. D.

    2015-04-01

    Self-assembly of rigid building blocks with explicit shape and symmetry is substantially influenced by the geometric factors and remains largely unexplored. We report the selective assembly behaviors of a class of precisely defined, nanosized giant tetrahedra constructed by placing different polyhedral oligomeric silsesquioxane (POSS) molecular nanoparticles at the vertices of a rigid tetrahedral framework. Designed symmetry breaking of these giant tetrahedra introduces precise positional interactions and results in diverse selectively assembled, highly ordered supramolecular lattices including a Frank-Kasper A15 phase, which resembles the essential structural features of certain metal alloys but at a larger length scale. These results demonstrate the power of persistent molecular geometry with balanced enthalpy and entropy in creating thermodynamically stable supramolecular lattices with properties distinct from those of other self-assembling soft materials.

  7. Children's Effortful Control and Academic Achievement: Mediation through Social Functioning

    ERIC Educational Resources Information Center

    Valiente, Carlos; Eisenberg, Nancy; Haugen, Rg; Spinrad, Tracy L.; Hofer, Claire; Liew, Jeffrey; Kupfer, Anne

    2011-01-01

    Research Findings: The purpose of this study was to test the premise that children's effortful control (EC) is prospectively related to their academic achievement and to specify mechanisms through which EC is related to academic success. We used data from 214 children (M age at Time 1 [T1] = 73 months) to test whether social functioning (e.g.,…

  8. A method to study precision grip control in viscoelastic force fields using a robotic gripper.

    PubMed

    Lambercy, Olivier; Metzger, Jean-Claude; Santello, Marco; Gassert, Roger

    2015-01-01

    Instrumented objects and multipurpose haptic displays have commonly been used to investigate sensorimotor control of grasping and manipulation. A major limitation of these devices, however, is the extent to which the experimenter can vary the interaction dynamics to fully probe sensorimotor control mechanisms. We propose a novel method to study precision grip control using a grounded robotic gripper with two moving, mechanically coupled finger pads instrumented with force sensors. The device is capable of stably rendering virtual mechanical properties with a wide dynamic range of achievable impedances. Eight viscoelastic force fields with different combinations of stiffness and damping parameters were implemented, and tested on eight healthy subjects performing 30 consecutive repetitions of a grasp, hold, and release task with time and position constraints. Rates of thumb and finger force were found to be highly correlated (r>0.9) during grasping, revealing that, despite the mechanical coupling of the two finger pads, subjects performed grasping movements in a physiological fashion. Subjects quickly adapted to the virtual dynamics (within seven trials), but, depending on the presented force field condition, used different control strategies to correctly perform the task. The proof of principle presented in this paper underscores the potential of such a one-degree-of-freedom robotic gripper to study neural control of grasping, and to provide novel insights on sensorimotor control mechanisms. PMID:25014953

  9. The purposes, achievements, and priorities of arms control

    SciTech Connect

    Brown, P.S.

    1987-09-01

    Arms control purposes include strengthening the framework of deterrence and reducing the threat of the use of nuclear weapons, reducing the dangers of attack and accidental nuclear war, and allowing more resources for the civilian economy. The paper briefly describes achievements in arms control since World War II. These include the Limited Test Ban Treaty (LTBT), Nonproliferation Treaty (NPT), Anti-Ballistic Missile Treaty (ABMT)-SALT I, SALT II, Threshold Test Ban Treaty (TTBT), Peaceful Nuclear Explosions Treaty (PNET), and Nuclear-Free Zones treaties. The author also discusses his views on what the priorities of arms control activities should be. (ACR)

  10. Precise flight-path control using a predictive algorithm

    NASA Technical Reports Server (NTRS)

    Hess, R. A.; Jung, Y. C.

    1991-01-01

    Generalized predictive control describes an algorithm for the control of dynamic systems in which a control input is generated that minimizes a quadratic cost function consisting of a weighted sum of errors between desired and predicted future system output and future predicted control increments. The output predictions are obtained from an internal model of the plant dynamics. A design technique is discussed for applying the single-input/single-output generalized predictive control algorithm to a problem of longitudinal/vertical terrain-following flight of a rotorcraft. By using the generalized predictive control technique to provide inputs to a classically designed stability and control augmentation system, it is demonstrated that a robust flight-path control system can be created that exhibits excellent tracking performance.

  11. Three Decades of Precision Orbit Determination Progress, Achievements, Future Challenges and its Vital Contribution to Oceanography and Climate Research

    NASA Technical Reports Server (NTRS)

    Luthcke, Scott; Rowlands, David; Lemoine, Frank; Zelensky, Nikita; Beckley, Brian; Klosko, Steve; Chinn, Doug

    2006-01-01

    Although satellite altimetry has been around for thirty years, the last fifteen beginning with the launch of TOPEX/Poseidon (TP) have yielded an abundance of significant results including: monitoring of ENS0 events, detection of internal tides, determination of accurate global tides, unambiguous delineation of Rossby waves and their propagation characteristics, accurate determination of geostrophic currents, and a multi-decadal time series of mean sea level trend and dynamic ocean topography variability. While the high level of accuracy being achieved is a result of both instrument maturity and the quality of models and correction algorithms applied to the data, improving the quality of the Climate Data Records produced from altimetry is highly dependent on concurrent progress being made in fields such as orbit determination. The precision orbits form the reference frame from which the radar altimeter observations are made. Therefore, the accuracy of the altimetric mapping is limited to a great extent by the accuracy to which a satellite orbit can be computed. The TP mission represents the first time that the radial component of an altimeter orbit was routinely computed with an accuracy of 2-cm. Recently it has been demonstrated that it is possible to compute the radial component of Jason orbits with an accuracy of better than 1-cm. Additionally, still further improvements in TP orbits are being achieved with new techniques and algorithms largely developed from combined Jason and TP data analysis. While these recent POD achievements are impressive, the new accuracies are now revealing subtle systematic orbit error that manifest as both intra and inter annual ocean topography errors. Additionally the construction of inter-decadal time series of climate data records requires the removal of systematic differences across multiple missions. Current and future efforts must focus on the understanding and reduction of these errors in order to generate a complete and

  12. Method and apparatus for precision control of radiometer

    NASA Technical Reports Server (NTRS)

    Estey, R. S.; Hanna, M. F. (Inventor)

    1984-01-01

    A radiometer controller of a radiation detector is provided with a calibration method and apparatus comprised of mounting all temperature sensitive elements of the controller in thermostatically controlled ovens during calibration and measurements, using a selected temperature that is above any which might be reached in the field. The instrument is calibrated in situ by adjusting heater power (EI) to the receptor cavity in the radiometer detector to a predetermined full scale level and is displayed by a meter.

  13. Control systems improvements in a precision coordinate measuring machine

    NASA Astrophysics Data System (ADS)

    Douglass, S. S.; Babelay, E. F., Jr.; Igou, R. E.; Woodard, L. M.; Green, W. L.

    1981-09-01

    A conventional, manually driven Moore No. 3 coordinate measuring machine at the Oak Ridge Y-12 Plant is being upgraded to provide a continuous-path numerical control capability and simultaneously serve as a vehicle for testing new machine slide-control concepts. Besides new lead screw drive motors, an NC machine control unit, and a closed-loop servo system, the machine has also been equipped with vibration isolation, air-bearing slideways, and laser interferometric position feedback. The present conventional slide servo system will be replaced with a digital servo system wherein various feedback and compensation techniques can be realized through the use of a high speed, dedicated digital processor. The improvements to data are described with emphasis on identification and compensation of the slide control systems.

  14. Precision tethered satellite attitude control. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Kline-Schoder, Robert J.

    1990-01-01

    Tethered spacecraft possess unique dynamic characteristics which make them advantageous for certain classes of experiments. One use for which tethers are particularly well suited is to provide an isolated platform for spaceborne observatories. The advantages of tethering a pointing platform 1 or 2 km from a space shuttle or space station are that, compared to placing the observatory on the parent spacecraft, vibrational disturbances are attenuated and contamination is eliminated. In practice, all satellites have some requirement on the attitude control of the spacecraft, and tethered satellites are no exception. It has previously been shown that conventional means of performing attitude control for tethered satellites are insufficient for any mission with pointing requirements more stringent than about 1 deg. This is due mainly to the relatively large force applied by the tether to the spacecraft. A particularly effective method of implementing attitude control for tethered satellites is to use this tether tension force to generate control torques by moving the tether attach point relative to the subsatellite center of mass. A demonstration of this attitude control technique on an astrophysical pointing platform has been proposed for a space shuttle flight test project and is referred to as the Kinetic Isolation Tether Experiment (KITE).

  15. Liquid-fuel valve with precise throttling control

    NASA Technical Reports Server (NTRS)

    Mcdougal, A. R.; Porter, R. N.; Riebling, R. W.

    1971-01-01

    Prototype liquid-fuel valve performs on-off and throttling functions in vacuum without component cold-welding or excessive leakage. Valve design enables simple and rapid disassembly and parts replacement and operates with short working stroke, providing maximum throttling sensitivity commensurate with good control.

  16. Controlling Precision Stepper Motors in Flight Using (Almost) No Parts

    NASA Technical Reports Server (NTRS)

    Randall, David

    2010-01-01

    This concept allows control of high-performance stepper motors with minimal parts count and minimal flight software complexity. Although it uses a small number of common flight-qualified parts and simple control algorithms, it is capable enough to meet demanding system requirements. Its programmable nature makes it trivial to implement changes to control algorithms both during integration & test and in flight. Enhancements such as microstepping, half stepping, back-emf compensation, and jitter reduction can be tailored to the requirements of a large variety of stepper motor based applications including filter wheels, focus mechanisms, antenna tracking subsystems, pointing and mobility. The hardware design (using an H-bridge motor controller IC) was adapted from JPL's MER mission, still operating on Mars. This concept has been fully developed and incorporated into the MCS instrument on MRO, currently operating in Mars orbit. It has been incorporated into the filter wheel mechanism and linear stage (focus) mechanism for the AMT instrument. On MCS/MRO, two of these circuits control the elevation and azimuth of the MCS telescope/radiometer assembly, allowing the instrument to continuously monitor the limb of the Martian atmosphere. Implementation on MCS/MRO resulted in a 4:1 reduction in the volume and mass required for the motor driver electronics (100:25 square inches of PCB space), producing a very compact instrument. In fact, all of the electronics for the MCS instrument are packaged within the movable instrument structure. It also saved approximately 3 Watts of power. Most importantly, the design enabled MCS to meet very its stringent maximum allowable torque disturbance requirements.

  17. COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. XV. Assessing the achievability and precision of time-delay measurements

    NASA Astrophysics Data System (ADS)

    Bonvin, V.; Tewes, M.; Courbin, F.; Kuntzer, T.; Sluse, D.; Meylan, G.

    2016-01-01

    COSMOGRAIL is a long-term photometric monitoring of gravitationally lensed quasars aimed at implementing Refsdal's time-delay method to measure cosmological parameters, in particular H0. Given the long and well sampled light curves of strongly lensed quasars, time-delay measurements require numerical techniques whose quality must be assessed. To this end, and also in view of future monitoring programs or surveys such as the LSST, a blind signal processing competition named Time Delay Challenge 1 (TDC1) was held in 2014. The aim of the present paper, which is based on the simulated light curves from the TDC1, is double. First, we test the performance of the time-delay measurement techniques currently used in COSMOGRAIL. Second, we analyse the quantity and quality of the harvest of time delays obtained from the TDC1 simulations. To achieve these goals, we first discover time delays through a careful inspection of the light curves via a dedicated visual interface. Our measurement algorithms can then be applied to the data in an automated way. We show that our techniques have no significant biases, and yield adequate uncertainty estimates resulting in reduced χ2 values between 0.5 and 1.0. We provide estimates for the number and precision of time-delay measurements that can be expected from future time-delay monitoring campaigns as a function of the photometric signal-to-noise ratio and of the true time delay. We make our blind measurements on the TDC1 data publicly available.

  18. A facility for precise temperature control applications in microgravity

    NASA Astrophysics Data System (ADS)

    Glicksman, M. E.; Lograsso, T. A.; Tirmizi, S. H.; Hahn, R. C.; Winsa, E.

    The general design, main components, and operation of the isothermal dendritic growth apparatus (IDGA) designed for microgravity experimentation are described. The four major subsystems of the IDGA are a temperature controlled thermostatic bath capable of milli-kelvin stability, a photographic data collection system, a crystal growth chamber, and a growth detection system to initiate data collection. Some of the specific experiments that could utilize the capabilities of the IDGA are dendritic growth in alloys, monotectic systems, life science experiments, and technological applications.

  19. A facility for precise temperature control applications in microgravity

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Lograsso, T. A.; Tirmizi, S. H.; Hahn, R. C.; Winsa, E.

    1988-01-01

    The general design, main components, and operation of the isothermal dendritic growth apparatus (IDGA) designed for microgravity experimentation are described. The four major subsystems of the IDGA are a temperature controlled thermostatic bath capable of milli-kelvin stability, a photographic data collection system, a crystal growth chamber, and a growth detection system to initiate data collection. Some of the specific experiments that could utilize the capabilities of the IDGA are dendritic growth in alloys, monotectic systems, life science experiments, and technological applications.

  20. The Space Technology-7 Disturbance Reduction System Precision Control Flight Validation Experiment Control System Design

    NASA Technical Reports Server (NTRS)

    O'Donnell, James R.; Hsu, Oscar C.; Maghami, Peirman G.; Markley, F. Landis

    2006-01-01

    As originally proposed, the Space Technology-7 Disturbance Reduction System (DRS) project, managed out of the Jet Propulsion Laboratory, was designed to validate technologies required for future missions such as the Laser Interferometer Space Antenna (LISA). The two technologies to be demonstrated by DRS were Gravitational Reference Sensors (GRSs) and Colloidal MicroNewton Thrusters (CMNTs). Control algorithms being designed by the Dynamic Control System (DCS) team at the Goddard Space Flight Center would control the spacecraft so that it flew about a freely-floating GRS test mass, keeping it centered within its housing. For programmatic reasons, the GRSs were descoped from DRS. The primary goals of the new mission are to validate the performance of the CMNTs and to demonstrate precise spacecraft position control. DRS will fly as a part of the European Space Agency (ESA) LISA Pathfinder (LPF) spacecraft along with a similar ESA experiment, the LISA Technology Package (LTP). With no GRS, the DCS attitude and drag-free control systems make use of the sensor being developed by ESA as a part of the LTP. The control system is designed to maintain the spacecraft s position with respect to the test mass, to within 10 nm/the square root of Hz over the DRS science frequency band of 1 to 30 mHz.

  1. High-Precision Temperature Control of a Crystal Growth Furnace at 1,500 C

    NASA Technical Reports Server (NTRS)

    Stenzel, Ch.; Hess, A.; Croell, A.; Breuer, D.; Sauermann, H.

    2012-01-01

    For crystal growth of semiconductor materials a short-term temperature stability of 0.1 C at 1500 C is one of the essential parameters to be addressed for achieving high-quality crystals. Hence, for temperature monitoring and control with high precision in a floating zone furnace two sets of thermo-sensors, type B thermocouples and optical fibre thermometers, have been implemented and successfully operated in the furnace for more than 2000 h. The optical fibre thermometers consist of an optical system made of sapphire (two fibres plus a prism in between for deflection) and transmit the infra-red radiation of the heater to the outside of the hot core of the furnace for pyrometric temperature measurement. A dedicated control algorithm has been set up which controlled the power settings to the individual heaters. Both sensor types showed no degradation after this period and yielded a short-term stability at 1200 C of 0.05 C (optical fibre thermometers), respectively 0.08 C (thermocouples).

  2. Precise computer controlled positioning of robot end effectors using force sensors

    NASA Technical Reports Server (NTRS)

    Shieh, Leang S.; Mcinnis, Bayliss C.

    1987-01-01

    A major problem in space applications of robotics and docking of spacecraft is the development of technology for automated precise positioning of mating components with smooth motion and soft contact. To achieve the above objective, a design method was developed for optimally placing the closed-loop poles of a discretized robotic control system at exact prescribed locations inside the unit circle of the complex z-plane. The design method combines the merits of the pole placement and the linear quadratic design approaches. The proposed design procedure is based on the assignment of one real eigenvalue or two complex conjugate (or real) eigenvalues at each design step. The method involves solutions of simple algebraic equations and this is considered to be efficient for on-line or off-line computations. Also, two methods for the linearization of the nonlinear model of a robotic manipulator were presented. Since automatic control of multi-degree freedom robotic manipulators involves high nonlinear equations of systems, a pilot project was proposed involving the control of a one-dimensional system. This simple system can be readily implemented for testing the concepts and algorithms.

  3. Development of a precision indentation and scratching system with a tool force and displacement control module

    NASA Astrophysics Data System (ADS)

    Park, Jae-jun; Kwon, Kihwan; Bang, Jinhyeok; Cho, Nahmgyoo; Han, Chang-soo; Choi, Nak-sam

    2007-04-01

    This article presents a tip-based micropatterning system with a precision device for measuring the machine force and the tool path. The machine force is obtained by a tool control module with a leaf spring and a capacitive displacement sensor. It is controlled to provide a force that ranges from 80 μN to 8 N. The force sensing unit, which is part of the module, is mounted on a PZT (PbZrTi) driven in-feed motion stage with a resolution of 1 nm. The work piece is set on an X-Y motion stage, and the position can be controlled with a tool path accuracy of 5 nm. Micropatterning and precision indentation experiments were performed, while the machined surfaces were examined by atomic force microscopy. From these results, the feasibility of the system for precise force-displacement control was verified for application in tip-based precision machining.

  4. Silylated Precision Particles for Controlled Release of Proteins

    PubMed Central

    Khodabandehlou, Khosrow; Kumbhar, Amar S.; Habibi, Sohrab; Pandya, Ashish A.; Luft, J. Christopher; Khan, Saad A.; DeSimone, Joseph M.

    2015-01-01

    With the recent advances in the development of novel protein based therapeutics, controlled delivery of these biologics is an important area of research. Herein, we report the synthesis of microparticles from bovine serum albumin (BSA) as a model protein using Particle Replication in Non-wetting Templates (PRINT) with specific size and shape. These particles were functionalized at room temperature using multifunctional chlorosilane that cross-link the particles to render them to slowly-dissolving in aqueous media. Mass spectrometric study of the reaction products of diisopropyldichlorosilane with individual components of the particles revealed that they are capable of reacting and forming cross-links. Energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were also used to confirm the functionalization of the particles. Cross sectional analysis using focused ion beam (FIB) and EDS proved that the functionalization occurs throughout the bulk of the particles and is not just limited to the surface. Circular dichroism data confirmed that the fraction of BSA molecules released from the particles retains its secondary structure thereby indicating that the system can be used for delivering protein based formulations while controlling the dissolution kinetics. PMID:25742193

  5. Development of an active truss element for control of precision structures

    NASA Technical Reports Server (NTRS)

    Anderson, Eric H.; Moore, Donald M.; Fanson, James L.; Ealey, Mark A.

    1990-01-01

    An active structural element for use in precision control of large space structures is described. The active member is intended to replace a passive strut in a truss-like structure. It incorporates an eddy current displacement sensor and an actuator that is either piezoelectric (PZT) or electrostrictive (PMN). The design of the device is summarized. Performance of separate PZT and PMN actuators is compared for several properties relevant to submicrometer control of precision structures.

  6. Precision distributorless ignition control system for internal combustion engines

    SciTech Connect

    Long, A.

    1987-03-17

    An electronic ignition system is described for controlling as a function of a selected engine parameter the ignition instants of an internal combustion engine having at least one cylinder, a piston, and a rotatable crankshaft coupled to the piston to be rotatably driven as combustions within the cylinder occur at the ignition instants. The crankshaft has at least one first reference position defining a positional relationship of the crankshaft to the cylinder, the crankshaft having a second reference position disposed a fixed angular distance before the first reference position considering the rotational direction of the crankshaft. The ignition instant is intended to occur upon the termination of a variable crankshaft arc beginning at the second reference position, the length of the crankshaft arc determined as a function of the selected engine parameter. The electronic ignition system comprises: (a) a rotor coupled to rotate with the crankshaft and having at least one first reference indicium and N second reference indicia thereon for each first reference indicium, the first reference indicium positionally related to the second reference position. The second reference indicia includes at least one second reference indicium aligned with the first reference indicium, the second reference indicia being spaced from each other by substantially equal angles; and (b) first and second signal generating means disposed at a point fixed in relation to the rotation of the crankshaft for providing respectively a first train of signals and a second train of signals.

  7. Chemical Sensors: Precisely Controlled Ultrathin Conjugated Polymer Films for Large Area Transparent Transistors and Highly Sensitive Chemical Sensors (Adv. Mater. 14/2016).

    PubMed

    Khim, Dongyoon; Ryu, Gi-Seong; Park, Won-Tae; Kim, Hyunchul; Lee, Myungwon; Noh, Yong-Young

    2016-04-01

    A precise control over the film thickness is a vital requirement for achievement of high performance in thin-film electronic devices. On page 2752, Y.-Y. Noh and co-workers develop an effective way to deposit a large-area and uniform ultrathin polymer film with a molecular-level precision via a simple wire-wound bar-coating method for high-performance organic transistors and gas sensors. PMID:27062168

  8. Parental Behavioural Control and Academic Achievement: Striking the Balance between Control and Involvement

    ERIC Educational Resources Information Center

    Kramer, Karen Z.

    2012-01-01

    Using a longitudinal US dataset (N = 6,134) we examine the relationship between parental behavioural control and academic achievement and explore the moderating role of parental involvement and parental warmth. Analyses using multiple hierarchical regression with clustering controls shows that parental behavioural control is negatively associated…

  9. Precision control of high temperature furnaces using an auxiliary power supply and charged practice current flow

    DOEpatents

    Pollock, George G.

    1997-01-01

    Two power supplies are combined to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved.

  10. Precision control of high temperature furnaces using an auxiliary power supply and charged particle current flow

    DOEpatents

    Pollock, G.G.

    1997-01-28

    Two power supplies are combined to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved. 5 figs.

  11. Nonlinear relative position control of precise formation flying using polynomial eigenstructure assignment

    NASA Astrophysics Data System (ADS)

    Wang, Feng; Chen, XueQin; Tsourdos, Antonios; White, Brian A.; Wu, YunHua

    2011-06-01

    A nonlinear relative position control algorithm is designed for spacecraft precise formation flying. Taking into account the effect of J2 gravitational perturbations and atmospheric drag, the relative motion dynamic equation of the formation flying is developed in a quasi-linear parameter-varying (QLPV) form without approximation. Base on this QLPV model, polynomial eigenstructure assignment (PEA) is applied to design the controller. The resulting PEA controller is a function of system state and parameters, and produces a closed-loop system with invariant performance over a wide range of conditions. Numerical simulation results show that the performance can fulfill precise formation flying requirements.

  12. A high precision attitude determination and control system for the UYS-1 nanosatellite

    NASA Astrophysics Data System (ADS)

    Chaurais, J. R.; Ferreira, H. C.; Ishihara, J. Y.; Borges, R. A.; Kulabukhov, A. M.; Larin, V. A.; Belikov, V. V.

    This paper presents the design of a high precision attitude determination and control system for the UYS-1 Ukrainian nanosatellite. Its main task is the 3-axis stabilization with less than 0.5° angle errors, so the satellite may take high precision photos of Earth's surface. To accomplish this task, this system comprises a star tracker and three reaction wheels. To avoid external disturbances and actuators faults, a PD-type and a PID-type robust controllers are simulated and the results are compared to an empirically adjusted PD controller.

  13. Development of a PWM precision spraying controller for unmanned aerial vehicles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper presents a new pulse width modulation (PWM) controller for unmanned aerial vehicle (UAV) precision sprayer for agriculture using a TL494 fix-frequency pulse width modulator together with a data acquisition board and developed software. The PWM controller was implemented through the guidan...

  14. Delay times of a LiDAR-guided precision sprayer control system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate flow control systems in triggering sprays against detected targets are needed for precision variable-rate sprayer development. System delay times due to the laser-sensor data buffer, software operation, and hydraulic-mechanical component response were determined for a control system used fo...

  15. Development of an active member using piezoelectric and electrostrictive actuation for control of precision structures

    NASA Technical Reports Server (NTRS)

    Anderson, E. H.; Moore, D. M.; Fanson, J. L.; Ealey, M. A.

    1990-01-01

    The design and development of a zero stiction active member containing piezoelectric and electrostrictive actuator motors is presented. The active member is intended for use in submicron control of structures. Experimental results are shown which illustrate actuator and device characteristics relevant to precision control applications.

  16. High precision spatial and temporal control of neural circuitry using a semi-automated multi-wavelength nanopatterning system

    NASA Astrophysics Data System (ADS)

    Mitnala, Sandhya; Huebshman, Michael; Herold, Christian; Herz, Joachim; Garner, Harold

    2009-02-01

    It has been one of the most discussed and intriguing topics -the quest to control neural circuitry as a precursor to decoding the operations of the human brain and manipulating its diseased state. Electrophysiology has created a gateway to control this circuitry with high precision. However, it is not practical to apply these techniques to living systems because these techniques are invasive and lack the spatial resolution necessary to properly address various neural cell components, cell assemblies or even tissues. Here we describe a new instrument that has the potential to replace the conventional patch clamping technique, the workhorse of neural physiology. A Digital Light Processing system from Texas Instruments and an Olympus IX71 inverted microscope were combined to achieve neuronal control at a subcellular spatial resolution. Accompanying these two technologies can be almost any light source, and for these experiments a pair of pulsed light sources that produced two pulse trains at different wavelengths tuned to activate or inactivate selectively the ChR2 and NpHR channels that were cloned to express light sensitive versions in neurons. Fura- 2 ratiometric fluorescent dye would be used to read-out calcium activity. The Pulsed light sources and a filter wheel are under computer control using a National Instruments digital control board and a CCD camera used to acquire real time cellular responses to the spatially controlled pulsed light channel activation would be controlled and synchronized using NI LabVIEW software. This will provide for a millisecond precision temporal control of neural circuitry. Thus this technology could provide researchers with an optical tool to control the neural circuitry both spatially and temporally with high precision.

  17. Evolution and Engineering of Precisely Controlled Ge Nanostructures on Scalable Array of Ordered Si Nano-pillars

    PubMed Central

    Wang, Shuguang; Zhou, Tong; Li, Dehui; Zhong, Zhenyang

    2016-01-01

    The scalable array of ordered nano-pillars with precisely controllable quantum nanostructures (QNs) are ideal candidates for the exploration of the fundamental features of cavity quantum electrodynamics. It also has a great potential in the applications of innovative nano-optoelectronic devices for the future quantum communication and integrated photon circuits. Here, we present a synthesis of such hybrid system in combination of the nanosphere lithography and the self-assembly during heteroepitaxy. The precise positioning and controllable evolution of self-assembled Ge QNs, including quantum dot necklace(QDN), QD molecule(QDM) and quantum ring(QR), on Si nano-pillars are readily achieved. Considering the strain relaxation and the non-uniform Ge growth due to the thickness-dependent and anisotropic surface diffusion of adatoms on the pillars, the comprehensive scenario of the Ge growth on Si pillars is discovered. It clarifies the inherent mechanism underlying the controllable growth of the QNs on the pillar. Moreover, it inspires a deliberate two-step growth procedure to engineer the controllable QNs on the pillar. Our results pave a promising avenue to the achievement of desired nano-pillar-QNs system that facilitates the strong light-matter interaction due to both spectra and spatial coupling between the QNs and the cavity modes of a single pillar and the periodic pillars. PMID:27353231

  18. Evolution and Engineering of Precisely Controlled Ge Nanostructures on Scalable Array of Ordered Si Nano-pillars.

    PubMed

    Wang, Shuguang; Zhou, Tong; Li, Dehui; Zhong, Zhenyang

    2016-01-01

    The scalable array of ordered nano-pillars with precisely controllable quantum nanostructures (QNs) are ideal candidates for the exploration of the fundamental features of cavity quantum electrodynamics. It also has a great potential in the applications of innovative nano-optoelectronic devices for the future quantum communication and integrated photon circuits. Here, we present a synthesis of such hybrid system in combination of the nanosphere lithography and the self-assembly during heteroepitaxy. The precise positioning and controllable evolution of self-assembled Ge QNs, including quantum dot necklace(QDN), QD molecule(QDM) and quantum ring(QR), on Si nano-pillars are readily achieved. Considering the strain relaxation and the non-uniform Ge growth due to the thickness-dependent and anisotropic surface diffusion of adatoms on the pillars, the comprehensive scenario of the Ge growth on Si pillars is discovered. It clarifies the inherent mechanism underlying the controllable growth of the QNs on the pillar. Moreover, it inspires a deliberate two-step growth procedure to engineer the controllable QNs on the pillar. Our results pave a promising avenue to the achievement of desired nano-pillar-QNs system that facilitates the strong light-matter interaction due to both spectra and spatial coupling between the QNs and the cavity modes of a single pillar and the periodic pillars. PMID:27353231

  19. Evolution and Engineering of Precisely Controlled Ge Nanostructures on Scalable Array of Ordered Si Nano-pillars

    NASA Astrophysics Data System (ADS)

    Wang, Shuguang; Zhou, Tong; Li, Dehui; Zhong, Zhenyang

    2016-06-01

    The scalable array of ordered nano-pillars with precisely controllable quantum nanostructures (QNs) are ideal candidates for the exploration of the fundamental features of cavity quantum electrodynamics. It also has a great potential in the applications of innovative nano-optoelectronic devices for the future quantum communication and integrated photon circuits. Here, we present a synthesis of such hybrid system in combination of the nanosphere lithography and the self-assembly during heteroepitaxy. The precise positioning and controllable evolution of self-assembled Ge QNs, including quantum dot necklace(QDN), QD molecule(QDM) and quantum ring(QR), on Si nano-pillars are readily achieved. Considering the strain relaxation and the non-uniform Ge growth due to the thickness-dependent and anisotropic surface diffusion of adatoms on the pillars, the comprehensive scenario of the Ge growth on Si pillars is discovered. It clarifies the inherent mechanism underlying the controllable growth of the QNs on the pillar. Moreover, it inspires a deliberate two-step growth procedure to engineer the controllable QNs on the pillar. Our results pave a promising avenue to the achievement of desired nano-pillar-QNs system that facilitates the strong light-matter interaction due to both spectra and spatial coupling between the QNs and the cavity modes of a single pillar and the periodic pillars.

  20. Precise Taper-Angle-Control of Via Holes for Reliable Scaled-Down Low-k/Cu Interconnects

    NASA Astrophysics Data System (ADS)

    Kume, Ippei; Inoue, Naoya; Saito, Shinobu; Furutake, Naoya; Kawahara, Jun; Hayashi, Yoshihiro

    2010-04-01

    A highly reliable Cu dual-damascene interconnect (DDI) was developed in a molecular-pore-stack (MPS) SiOCH film (k = 2.5) with precise taper angle control at the top and bottom of via holes. The durable MPS film with the carbon-rich composition revealed no reliability deterioration in the time-dependent dielectric breakdown (TDDB) between the 140-nm pitched lines. The stres-induced voiding (SiV) was suppressed completely by precise taper angle control both at the top and bottom of via holes. A shallow-tapered via and a stepped via, in which these top taper angles (θtop) were greater than 45° while keeping the bottom angle (θbtm) steep at approximately 90°, improved the SiV reliability referred to a deep-tapered via with θbtm≪90°. Finite element method (FEM) simulation well explains the dependence of SiV reliability on both θtop and θbtm the increment of θtop reduces the stress gradient under the via, while the decrease in θbtm enlarges the stress gradient. Namely, the precise taper angle control of both the top and bottom via is very important to improve the SiV reliability, and the shallow-tapered and the stepped vias in the MPS film were confirmed to achieve high endurance against the SiV due to relaxation of the stress gradient under the via.

  1. Precise Taper-Angle-Control of Via Holes for Reliable Scaled-Down Low-k/Cu Interconnects

    NASA Astrophysics Data System (ADS)

    Ippei Kume,; Naoya Inoue,; Shinobu Saito,; Naoya Furutake,; Jun Kawahara,; Yoshihiro Hayashi,

    2010-04-01

    A highly reliable Cu dual-damascene interconnect (DDI) was developed in a molecular-pore-stack (MPS) SiOCH film (k = 2.5) with precise taper angle control at the top and bottom of via holes. The durable MPS film with the carbon-rich composition revealed no reliability deterioration in the time-dependent dielectric breakdown (TDDB) between the 140-nm pitched lines. The stres-induced voiding (SiV) was suppressed completely by precise taper angle control both at the top and bottom of via holes. A shallow-tapered via and a stepped via, in which these top taper angles (θtop) were greater than 45° while keeping the bottom angle (θbtm) steep at approximately 90°, improved the SiV reliability referred to a deep-tapered via with θbtm≪ 90°. Finite element method (FEM) simulation well explains the dependence of SiV reliability on both θtop and θbtm; the increment of θtop reduces the stress gradient under the via, while the decrease in θbtm enlarges the stress gradient. Namely, the precise taper angle control of both the top and bottom via is very important to improve the SiV reliability, and the shallow-tapered and the stepped vias in the MPS film were confirmed to achieve high endurance against the SiV due to relaxation of the stress gradient under the via.

  2. A Precision Dose Control Circuit for Maskless E-Beam Lithography With Massively Parallel Vertically Aligned Carbon Nanofibers

    SciTech Connect

    Eliza, Sazia A.; Islam, Syed K; Rahman, Touhidur; Bull, Nora D; Blalock, Benjamin; Baylor, Larry R; Ericson, Milton Nance; Gardner, Walter L

    2011-01-01

    This paper describes a highly accurate dose control circuit (DCC) for the emission of a desired number of electrons from vertically aligned carbon nanofibers (VACNFs) in a massively parallel maskless e-beam lithography system. The parasitic components within the VACNF device cause a premature termination of the electron emission, resulting in underexposure of the photoresist. In this paper, we compensate for the effects of the parasitic components and noise while reducing the area of the chip and achieving a precise count of emitted electrons from the VACNFs to obtain the optimum dose for the e-beam lithography.

  3. Achieving high precision photometry for transiting exoplanets with a low cost robotic DSLR-based imaging system

    NASA Astrophysics Data System (ADS)

    Guyon, Olivier; Martinache, Frantz

    2012-09-01

    We describe a low cost high precision photometric imaging system, which has been in robotic operation for one and half year on the Mauna Loa observatory (Hawaii). The system, which can be easily duplicated, is composed of commercially available components, offers a 150 sq deg field with two 70mm entrance apertures, and 6-band simultaneous photometry at a 0.01 Hz sampling. The detectors are low-cost commercial 3-color CMOS array, which we show is an attractive costeffective choice for high precision transit photometry. We describe the design of the system and show early results. A new data processing technique was developed to overcome pixelization and color errors. We show that this technique, which can also be applied on non-color imaging systems, essentially removes pixelization errors in the photometric signal, and we demonstrate on-sky photometric precision approaching fundamental error sources (photon noise and atmospheric scintillation). We conclude that our approach is ideally suited for exoplanet transit survey with multiple units. We show that in this scenario, the success metric is purely cost per etendue, which is at less than $10000s per square meter square degree for our system.

  4. Method of achieving the controlled release of thermonuclear energy

    DOEpatents

    Brueckner, Keith A.

    1986-01-01

    A method of achieving the controlled release of thermonuclear energy by illuminating a minute, solid density, hollow shell of a mixture of material such as deuterium and tritium with a high intensity, uniformly converging laser wave to effect an extremely rapid build-up of energy in inwardly traveling shock waves to implode the shell creating thermonuclear conditions causing a reaction of deuterons and tritons and a resultant high energy thermonuclear burn. Utilizing the resulting energy as a thermal source and to breed tritium or plutonium. The invention also contemplates a laser source wherein the flux level is increased with time to reduce the initial shock heating of fuel and provide maximum compression after implosion; and, in addition, computations and an equation are provided to enable the selection of a design having a high degree of stability and a dependable fusion performance by establishing a proper relationship between the laser energy input and the size and character of the selected material for the fusion capsule.

  5. Minitron II system for precise control of the plant growth environment

    NASA Technical Reports Server (NTRS)

    Knight, Sharon L.; Akers, Carolyn P.; Akers, S. W.; Mitchell, Cary A.

    1988-01-01

    The Minitron II system which accommodates hydroponic culture and separate control of atmospheric composition in individual chambers is used to measure gas-exchange by small crop canopies in the undisturbed plant growth environment. It is concluded that the system is capable of providing separate controlled environments for multiple small plants with adequate precision and at relatively low cost when coupled with appropriate control systems.

  6. Precision-controlled elution of a 82Sr/82Rb generator for cardiac perfusion imaging with positron emission tomography.

    PubMed

    Klein, R; Adler, A; Beanlands, R S; Dekemp, R A

    2007-02-01

    A rubidium-82 ((82)Rb) elution system is described for use with positron emission tomography. Due to the short half-life of (82)Rb (76 s), the system physics must be modelled precisely to account for transport delay and the associated activity decay and dispersion. Saline flow is switched between a (82)Sr/(82)Rb generator and a bypass line to achieve a constant-activity elution of (82)Rb. Pulse width modulation (PWM) of a solenoid valve is compared to simple threshold control as a means to simulate a proportional valve. A predictive-corrective control (PCC) algorithm is developed which produces a constant-activity elution within the constraints of long feedback delay and short elution time. The system model parameters are adjusted through a self-tuning algorithm to minimize error versus the requested time-activity profile. The system is self-calibrating with 2.5% repeatability, independent of generator activity and elution flow rate. Accurate 30 s constant-activity elutions of 10-70% of the total generator activity are achieved using both control methods. The combined PWM-PCC method provides significant improvement in precision and accuracy of the requested elution profiles. The (82)Rb elution system produces accurate and reproducible constant-activity elution profiles of (82)Rb activity, independent of parent (82)Sr activity in the generator. More reproducible elution profiles may improve the quality of clinical and research PET perfusion studies using (82)Rb. PMID:17228112

  7. Precise control of coupling strength in photonic molecules over a wide range using nanoelectromechanical systems

    NASA Astrophysics Data System (ADS)

    Du, Han; Zhang, Xingwang; Chen, Guoqiang; Deng, Jie; Chau, Fook Siong; Zhou, Guangya

    2016-04-01

    Photonic molecules have a range of promising applications including quantum information processing, where precise control of coupling strength is critical. Here, by laterally shifting the center-to-center offset of coupled photonic crystal nanobeam cavities, we demonstrate a method to precisely and dynamically control the coupling strength of photonic molecules through integrated nanoelectromechanical systems with a precision of a few GHz over a range of several THz without modifying the nature of their constituent resonators. Furthermore, the coupling strength can be tuned continuously from negative (strong coupling regime) to zero (weak coupling regime) and further to positive (strong coupling regime) and vice versa. Our work opens a door to the optimization of the coupling strength of photonic molecules in situ for the study of cavity quantum electrodynamics and the development of efficient quantum information devices.

  8. Precise control of coupling strength in photonic molecules over a wide range using nanoelectromechanical systems.

    PubMed

    Du, Han; Zhang, Xingwang; Chen, Guoqiang; Deng, Jie; Chau, Fook Siong; Zhou, Guangya

    2016-01-01

    Photonic molecules have a range of promising applications including quantum information processing, where precise control of coupling strength is critical. Here, by laterally shifting the center-to-center offset of coupled photonic crystal nanobeam cavities, we demonstrate a method to precisely and dynamically control the coupling strength of photonic molecules through integrated nanoelectromechanical systems with a precision of a few GHz over a range of several THz without modifying the nature of their constituent resonators. Furthermore, the coupling strength can be tuned continuously from negative (strong coupling regime) to zero (weak coupling regime) and further to positive (strong coupling regime) and vice versa. Our work opens a door to the optimization of the coupling strength of photonic molecules in situ for the study of cavity quantum electrodynamics and the development of efficient quantum information devices. PMID:27097883

  9. Precise control of coupling strength in photonic molecules over a wide range using nanoelectromechanical systems

    PubMed Central

    Du, Han; Zhang, Xingwang; Chen, Guoqiang; Deng, Jie; Chau, Fook Siong; Zhou, Guangya

    2016-01-01

    Photonic molecules have a range of promising applications including quantum information processing, where precise control of coupling strength is critical. Here, by laterally shifting the center-to-center offset of coupled photonic crystal nanobeam cavities, we demonstrate a method to precisely and dynamically control the coupling strength of photonic molecules through integrated nanoelectromechanical systems with a precision of a few GHz over a range of several THz without modifying the nature of their constituent resonators. Furthermore, the coupling strength can be tuned continuously from negative (strong coupling regime) to zero (weak coupling regime) and further to positive (strong coupling regime) and vice versa. Our work opens a door to the optimization of the coupling strength of photonic molecules in situ for the study of cavity quantum electrodynamics and the development of efficient quantum information devices. PMID:27097883

  10. The high precision control of the satellites formation for diffraction imaging

    NASA Astrophysics Data System (ADS)

    Yang, Guang; He, Liang; Song, Ting; Sun, Binglei; Hao, Tianwei

    2016-01-01

    To satisfy need of high resolution observation from space. This article elaborates a method of high precision spacecraft formation control based on file diffraction theory. Improving the spacecraft control accuracy to millimeter is a challenge. With the method in this article this challenge can be solved. The algorithm in this article concerning the vibration of spacecraft and based on dynamic modeling of even relative quaternion theory deduced a method of attitude and orbit integrated control. Using this control algorithm to simulation can get the result that it can make the spacecraft integrate formation control as the technical basis of space high resolution observation.

  11. Malaria in Turkey: successful control and strategies for achieving elimination.

    PubMed

    Özbilgina, Ahmet; Topluoglu, Seher; Es, Saffet; Islek, Elif; Mollahaliloglu, Salih; Erkoc, Yasin

    2011-01-01

    Turkey is located in the middle of Asia, Africa and Europe, close to Caucasia, Balkans and Middle East in subtropical climate zone. Malaria has been known since the early ages of human history and it was one of the leading diseases in Anatolian history, as well. Today, chloroquine-sensitive Plasmodium vivax is the only agent of autochthonous malaria cases in Turkey. The other Plasmodium species identified are isolated from imported cases of malaria. The most common vector of malaria in Turkey is Anopheles sacharovi followed by An. superpictus, An. maculipennis and An. subalpinus. In 2009, pre-elimination stage of Malaria Program was started due to dramatic decline in the number of malaria cases in Turkey (Total, 84; 38 autochthonous cases only in 26 foci in south-eastern Anatolia, and 46 imported cases; incidence: 0.1/100,000). As there were no detected cases of new autochthonous malaria in the first 8 months of 2010, elimination stage was started. The role of the persistent policies and successful applications of the Ministry of Health, such as the strict control of the patients using anti-malarial drugs especially chloroquine, avoidance of resistant insecticides, facilitation of access to patients via Health Transformation Program (HTP), establishment of close contact with the patients' families, and improvement of reporting and surveillance system, was essential. In addition, improvement maintained in the motivations and professional rights of malaria workers, as well in the coordination of field studies and maintenance of a decline or termination in vector-to-person transmission were all achieved with the insistent policies of the Ministry of Health. Other factors that probably contributed to elimination studies include lessening of military operations in south-eastern Anatolia and the lowering of malaria cases in neighbouring countries in recent years. Free access to health services concerning malaria is still successfully conducted throughout the country

  12. Study on control structure analysis and optimization of high-precision measurement platform for optical aspheric surface

    NASA Astrophysics Data System (ADS)

    Ke, Xiaolong; Guo, Yinbiao; Wang, Zhengzhong; Liu, Jianchun

    2009-05-01

    Taking high generality and efficiency into account, this paper presents a measurement and control means based on high-precision measurement platform including high-precision linear motors, contact and non-contact measurement sensor of 0.1um resolution and a new developed measuring software. This platform aims to achieve high-precision measurement for all kinds of optical aspheric workpieces for detection accuracy of 2um/200*200mm. In this paper, a measurement platform which consists of granite gantry framework, 3 axes linear motors, circle grating rotary encoder, grating linear scales, 4 axes motion control card, linear motion ball guide, contacting and non-contacting measurement sensor and so on, is designed and implemented. Through finite element stress analysis, it can find that the framework well fulfills the accuracy demand. And the performance comparison between linear motors and piezoelectric ceramics motors is then discussed. Further, it also compares the coordinated motion of "circle grating rotary encoder+2 axes linear motors" with the coordinated motion of "3 axes linear motors" to find out the difference in measurement accuracy by experiment data. Here, a better scheme for kinematic locus planning is proposed for making sure all axes have better dynamic characteristics. Aiming at various characteristics of optical workpieces, the different measurement paths are also provided. Finally, the experiments for this purpose are done to validate the measurement platform accuracy.

  13. Precision placement of corn gluten meal for weed control in organic vegetable production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic vegetable producers continue to rank weeds as one of their most troublesome, time consuming, and costly production problems. As a result of the limited number of organically approved weed control herbicides, the precision placement of these materials increases their potential usefulness thr...

  14. Plasma luminescence feedback control system for precise ultrashort pulse laser tissue ablation

    NASA Astrophysics Data System (ADS)

    Kim, Beop-Min; Feit, Michael D.; Rubenchik, Alexander M.; Gold, David M.; Darrow, Christopher B.; Marion, John E., II; Da Silva, Luiz B.

    1998-05-01

    Plasma luminescence spectroscopy was used for precise ablation of bone tissue without damaging nearby soft tissue using an ultrashort pulse laser. Strong contrast of the luminescence spectra between bone marrow and spinal cord provided the real time feedback control so bone tissue is selectively ablated while preserving the spinal cord.

  15. Movement Precision and Amplitude as Separate Factors in the Control of Movement.

    ERIC Educational Resources Information Center

    Kerr, Robert

    The purpose of this study was to assess Welford's dual controlling factor interpretation of Fitts' Law--describing movement time as being a linear function of movement distance (or amplitude) and the required precision of the movement (or target width). Welford's amplification of the theory postulates that two separate processes ought to be…

  16. Precision placement of corn gluten meal for weed control in organic vegetable production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers of organic vegetables continue to rank weeds as one of their most troublesome, time consuming, and costly production problems. As a result of the limited number of organically approved weed control herbicides, the precision placement of these materials increases their potential usefulness...

  17. Plasma luminescence feedback control system for precise ultrashort pulse laser tissue ablation

    SciTech Connect

    Kim, B.M.; Feit, M.D.; Rubenchick, A.M.; Gold, D.M.; Darrown, C.B.; Da Silva, L.B.

    1998-01-01

    Plasma luminescence spectroscopy was used for precise ablation of bone tissue without damaging nearby soft tissue using ultrashort pulse laser (USPL). Strong contrast of the luminescence spectra between bone marrow and spinal cord provided the real time feedback control so that only bone tissue can be selectively ablated while preserving the spinal cord.

  18. Toward Controlled Hierarchical Heterogeneities in Giant Molecules with Precisely Arranged Nano Building Blocks.

    PubMed

    Zhang, Wei; Huang, Mingjun; Su, Hao; Zhang, Siyu; Yue, Kan; Dong, Xue-Hui; Li, Xiaopeng; Liu, Hao; Zhang, Shuo; Wesdemiotis, Chrys; Lotz, Bernard; Zhang, Wen-Bin; Li, Yiwen; Cheng, Stephen Z D

    2016-01-27

    Herein we introduce a unique synthetic methodology to prepare a library of giant molecules with multiple, precisely arranged nano building blocks, and illustrate the influence of minute structural differences on their self-assembly behaviors. The T8 polyhedral oligomeric silsesquioxane (POSS) nanoparticles are orthogonally functionalized and sequentially attached onto the end of a hydrophobic polymer chain in either linear or branched configuration. The heterogeneity of primary chemical structure in terms of composition, surface functionality, sequence, and topology can be precisely controlled and is reflected in the self-assembled supramolecular structures of these giant molecules in the condensed state. This strategy offers promising opportunities to manipulate the hierarchical heterogeneities of giant molecules via precise and modular assemblies of various nano building blocks. PMID:27163025

  19. Toward Controlled Hierarchical Heterogeneities in Giant Molecules with Precisely Arranged Nano Building Blocks

    PubMed Central

    2016-01-01

    Herein we introduce a unique synthetic methodology to prepare a library of giant molecules with multiple, precisely arranged nano building blocks, and illustrate the influence of minute structural differences on their self-assembly behaviors. The T8 polyhedral oligomeric silsesquioxane (POSS) nanoparticles are orthogonally functionalized and sequentially attached onto the end of a hydrophobic polymer chain in either linear or branched configuration. The heterogeneity of primary chemical structure in terms of composition, surface functionality, sequence, and topology can be precisely controlled and is reflected in the self-assembled supramolecular structures of these giant molecules in the condensed state. This strategy offers promising opportunities to manipulate the hierarchical heterogeneities of giant molecules via precise and modular assemblies of various nano building blocks. PMID:27163025

  20. Post-buckling analysis for the precisely controlled buckling of thin film encapsulated by elastomeric subsrates.

    SciTech Connect

    Jiang, H.; Sun, Y.; Rogers, J. A.; Huang, Y.; Arizona State Univ.; Univ. of Illinois; Northwestern Univ.

    2008-04-01

    The precisely controlled buckling of stiff thin films (e.g., Si or GaAs nano ribbons) on the patterned surface of elastomeric substrate (e.g., poly(dimethylsiloxane) (PDMS)) with periodic inactivated and activated regions was designed by Sun et al. [Sun, Y., Choi, W.M., Jiang, H., Huang, Y.Y., Rogers, J.A., 2006. Controlled buckling of semiconductor nanoribbons for stretchable electronics. Nature Nanotechnology 1, 201-207] for important applications of stretchable electronics. We have developed a post-buckling model based on the energy method for the precisely controlled buckling to study the system stretchability. The results agree with Sun et al.'s (2006) experiments without any parameter fitting, and the system can reach 120% stretchability.

  1. Precision Pointing Control System (PPCS) system design and analysis. [for gimbaled experiment platforms

    NASA Technical Reports Server (NTRS)

    Frew, A. M.; Eisenhut, D. F.; Farrenkopf, R. L.; Gates, R. F.; Iwens, R. P.; Kirby, D. K.; Mann, R. J.; Spencer, D. J.; Tsou, H. S.; Zaremba, J. G.

    1972-01-01

    The precision pointing control system (PPCS) is an integrated system for precision attitude determination and orientation of gimbaled experiment platforms. The PPCS concept configures the system to perform orientation of up to six independent gimbaled experiment platforms to design goal accuracy of 0.001 degrees, and to operate in conjunction with a three-axis stabilized earth-oriented spacecraft in orbits ranging from low altitude (200-2500 n.m., sun synchronous) to 24 hour geosynchronous, with a design goal life of 3 to 5 years. The system comprises two complementary functions: (1) attitude determination where the attitude of a defined set of body-fixed reference axes is determined relative to a known set of reference axes fixed in inertial space; and (2) pointing control where gimbal orientation is controlled, open-loop (without use of payload error/feedback) with respect to a defined set of body-fixed reference axes to produce pointing to a desired target.

  2. Precise Control of Movement Kinematics by Optogenetic Inhibition of Purkinje Cell Activity

    PubMed Central

    Heiney, Shane A.; Kim, Jinsook; Augustine, George J.

    2014-01-01

    Purkinje cells (PCs) of the cerebellar cortex are necessary for controlling movement with precision, but a mechanistic explanation of how the activity of these inhibitory neurons regulates motor output is still lacking. We used an optogenetic approach in awake mice to show for the first time that transiently suppressing spontaneous activity in a population of PCs is sufficient to cause discrete movements that can be systematically modulated in size, speed, and timing depending on how much and how long PC firing is suppressed. We further demonstrate that this fine control of movement kinematics is mediated by a graded disinhibition of target neurons in the deep cerebellar nuclei. Our results prove a long-standing model of cerebellar function and provide the first demonstration that suppression of inhibitory signals can act as a powerful mechanism for the precise control of behavior. PMID:24501371

  3. Precise SDF1-mediated cell guidance is achieved through ligand clearance and microRNA-mediated decay

    PubMed Central

    Lewellis, Stephen W.; Nagelberg, Danielle; Subedi, Abhi; Staton, Alison; LeBlanc, Michelle; Giraldez, Antonio

    2013-01-01

    During animal development, SDF1 simultaneously guides various cell types to different targets. As many targets are in close proximity to one another, it is unclear how the system avoids mistargeting. Zebrafish trigeminal sensory neurons express the SDF1 receptor Cxcr4b and encounter multiple SDF1 sources during migration, but ignore all but the correct one. We show that miR-430 and Cxcr7b regulation of SDF1a are required for precise guidance. In the absence of miR-430 or Cxcr7b, neurons responded to ectopic SDF1a sources along their route and did not reach their target. This was due to a failure to clear SDF1a transcript and protein from sites of expression that the migrating neurons had already passed. Our findings suggest an “attractive path” model in which migrating cells closely follow a dynamic SDF1a source that is refined on a transcript and protein level by miR-430 and Cxcr7b, respectively. PMID:23382464

  4. Self-Esteem, Locus of Control, and Student Achievement.

    ERIC Educational Resources Information Center

    Sterbin, Allan; Rakow, Ernest

    The direct effects of locus of control and self-esteem on standardized test scores were studied. The relationships among the standardized test scores and measures of locus of control and self-esteem for 12,260 students from the National Education Longitudinal Study 1994 database were examined, using the same definition of locus of control and…

  5. Concurrently adjusting interrelated control parameters to achieve optimal engine performance

    DOEpatents

    Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

    2015-12-01

    Methods and systems for real-time engine control optimization are provided. A value of an engine performance variable is determined, a value of a first operating condition and a value of a second operating condition of a vehicle engine are detected, and initial values for a first engine control parameter and a second engine control parameter are determined based on the detected first operating condition and the detected second operating condition. The initial values for the first engine control parameter and the second engine control parameter are adjusted based on the determined value of the engine performance variable to cause the engine performance variable to approach a target engine performance variable. In order to cause the engine performance variable to approach the target engine performance variable, adjusting the initial value for the first engine control parameter necessitates a corresponding adjustment of the initial value for the second engine control parameter.

  6. Precise computer controlled positioning of robot end effectors using sensory feedback

    NASA Technical Reports Server (NTRS)

    Wang, J. C.; Tsai, J. S. H.; Mcinnis, B. C.; Shieh, L. S.

    1988-01-01

    A preliminary study of the combined position/force control using sensory feedback for a one-dimensional manipulator model, which may count for the spacecraft docking problem or to be extended to the multijoint robot manipulator problem, has been performed. The additional degrees of freedom introduced by the compliant force sensor is included in the system dynamics in the design of precise position control. State feedback based on pole placement method and with integral control is used to design the position controller. A simple constant gain force controller is used as an example to illustrate the dependence of the stability and steady-state accuracy of the overall position/force control on the design of the inner position controller. Supportive simulation results are also provided.

  7. Adaptive control of piezoelectric fast steering mirror for high precision tracking application

    NASA Astrophysics Data System (ADS)

    Wang, Geng; Rao, Changhui

    2015-03-01

    A piezoelectric fast steering mirror (PFSM) is a complex, strong coupling nonlinear system that integrates optics, mechanics, electrics, and control. Due to the existence of hysteresis nonlinearity, mechanical resonance, and all kinds of disturbances, precise tracking control of a PFSM is a challenging task. This paper presents a comprehensive study of modeling, controller design, and simulation evaluation for a PFSM system. First a general model of a PFSM system integrating mechanical dynamics, electrical dynamics, and hysteresis nonlinearity is proposed, and then a robust adaptive controller is developed under both unknown hysteresis nonlinearities and parameter uncertainties. The parameters needed directly in the formulation of the controller are adaptively estimated. The proposed control law ensures the uniform boundedness of all signals in the closed-loop system. Furthermore, a stability analysis of the control system is performed to guarantee that the output tracking error converges to zero asymptotically. Finally, simulation tests with different motion trajectories are conducted to verify the effectiveness of the proposed method.

  8. Precise computer controlled positioning of robot end effectors using force sensors

    NASA Technical Reports Server (NTRS)

    Shieh, L. S.; Mcinnis, B. C.; Wang, J. C.

    1988-01-01

    A thorough study of combined position/force control using sensory feedback for a one-dimensional manipulator model, which may count for the spacecraft docking problem or be extended to the multi-joint robot manipulator problem, was performed. The additional degree of freedom introduced by the compliant force sensor is included in the system dynamics in the design of precise position control. State feedback based on the pole placement method and with integral control is used to design the position controller. A simple constant gain force controller is used as an example to illustrate the dependence of the stability and steady-state accuracy of the overall position/force control upon the design of the inner position controller. Supportive simulation results are also provided.

  9. The centering and leveling adjustment and control technology for the ultra-precision turntable

    NASA Astrophysics Data System (ADS)

    Tian, Yanrong; Wang, Yun; Wang, Longxiao; Zhao, Weirui

    2015-08-01

    In order to realize the centering and leveling adjustment in large aperture spherical and aspheric surface shape measurement, by combining with the aerostatic bearing rotary shaft, working platform, high performance servo motor, photoelectric encoder, the micro displacement actuator of XYZ axis, sensor and Renishaw circular grating ,a set of fast and ultra-precision centering and leveling adjustment system is developed .The system is based on large range of air lubrication technology for high precision aerostatic bearing turntable, using the principle of three point supporting method, and the driving of tens nanometer resolution are provided by a piezoelectric micro displacement actuator. To realize the automatical centering and leveling adjustment in the large aperture spherical and aspheric surface shape measurement system, a software control program is designed with VC++. Through experimental test: centering adjusting operation can eventually converges to 0.5μm, leveling adjusting operation can eventually converges to 0.2 ", the time of adjusting can be less than 120 s. The experimental results shows that, compared with the previous system, the structure of the developed measurement and control system is more simple, more flexible, it can meet the demands of high precision, high resolution, large adjusting range, no friction, easy to drive, and high bearing stiffness etc in eccentric adjusting operation of optical precision measurement well.

  10. Purpose Plus: Supporting Youth Purpose, Control, and Academic Achievement

    ERIC Educational Resources Information Center

    Pizzolato, Jane Elizabeth; Brown, Elizabeth Levine; Kanny, Mary Allison

    2011-01-01

    Research in the past decade suggests that a persistent achievement gap between students from low-income minority backgrounds and higher-income white backgrounds may be rooted in theories of student motivation and youth purpose. Yet limited research exists regarding the role of purpose on positive youth development as it pertains to academic…

  11. Speed Control Law for Precision Terminal Area In-Trail Self Spacing

    NASA Technical Reports Server (NTRS)

    Abbott, Terence S.

    2002-01-01

    This document describes a speed control law for precision in-trail airborne self-spacing during final approach. This control law was designed to provide an operationally viable means to obtain a desired runway threshold crossing time or minimum distance, one aircraft relative to another. The control law compensates for dissimilar final approach speeds between aircraft pairs and provides guidance for a stable final approach. This algorithm has been extensively tested in Monte Carlo simulation and has been evaluated in piloted simulation, with preliminary results indicating acceptability from operational and workload standpoints.

  12. Two-axis Beam Steering Mirror Control system for Precision Pointing and Tracking Applications

    SciTech Connect

    Ulander, K

    2006-02-08

    Precision pointing and tracking of laser beams is critical in numerous military and industrial applications. This is particularly true for systems requiring atmospheric beam propagation. Such systems are plagued by environmental influences which cause the optical signal to break up and wander. Example applications include laser communications, precision targeting, active imaging, chemical remote sensing, and laser vibrometry. The goal of this project is to build a beam steering system using a two-axis mirror to maintain precise pointing control. Ultimately, position control to 0.08% accuracy (40 {micro}rad) with a bandwidth of 200 Hz is desired. The work described encompasses evaluation of the instrumentation system and the subsequent design and implementation of an analog electronic controller for a two-axis mirror used to steer the beam. The controller operates over a wide temperature range, through multiple mirror resonances, and is independent of specific mirrors. The design was built and successfully fielded in a Lawrence Livermore National Laboratory free-space optics experiment. All measurements and performance parameters are derived from measurements made on actual hardware that was built and field tested. In some cases, specific design details have been omitted that involve proprietary information pertaining to Lawrence Livermore National Laboratory patent positions and claims. These omissions in no way impact the general validity of the work or concepts presented in this thesis.

  13. Controlling open quantum systems: tools, achievements, and limitations

    NASA Astrophysics Data System (ADS)

    Koch, Christiane P.

    2016-06-01

    The advent of quantum devices, which exploit the two essential elements of quantum physics, coherence and entanglement, has sparked renewed interest in the control of open quantum systems. Successful implementations face the challenge of preserving relevant nonclassical features at the level of device operation. A major obstacle is decoherence, which is caused by interaction with the environment. Optimal control theory is a tool that can be used to identify control strategies in the presence of decoherence. Here we review recent advances in optimal control methodology that allow typical tasks in device operation for open quantum systems to be tackled and discuss examples of relaxation-optimized dynamics. Optimal control theory is also a useful tool to exploit the environment for control. We discuss examples and point out possible future extensions.

  14. Controlling open quantum systems: tools, achievements, and limitations.

    PubMed

    Koch, Christiane P

    2016-06-01

    The advent of quantum devices, which exploit the two essential elements of quantum physics, coherence and entanglement, has sparked renewed interest in the control of open quantum systems. Successful implementations face the challenge of preserving relevant nonclassical features at the level of device operation. A major obstacle is decoherence, which is caused by interaction with the environment. Optimal control theory is a tool that can be used to identify control strategies in the presence of decoherence. Here we review recent advances in optimal control methodology that allow typical tasks in device operation for open quantum systems to be tackled and discuss examples of relaxation-optimized dynamics. Optimal control theory is also a useful tool to exploit the environment for control. We discuss examples and point out possible future extensions. PMID:27143501

  15. The design of a stepper motor control-based high-precision varifocal imaging optical system

    NASA Astrophysics Data System (ADS)

    Xiang, Bai

    2012-11-01

    This study, while introducing the theories and makeup of conventional cam varifocal system, indicates the two faults stemming from their inherent mechanism and potentiometer-based focal-length measurement: 1) inability to stop optic axis vibration and 2) considerable error in real-time output of focal-length value. As a result, a stepper motor, instead of cam mechanism, was employed to control mirrors of variofocus and mirrors of compensation in moving accurately along straight-ling rails so that continuous focal-length variation and surface image positioning were accomplished; a linear encoder was substituted for potentiometer in realizing real-time output of focal-length value and also in closed-loop control of stepper motor. Compared with the cam mechanism, this system provides 90% less vibration and 80% more positioning precision, thereby basically solving the problems of the cam system and enabling the high-precision angular measurement.

  16. Design Considerations for Miniaturized Control Moment Gyroscopes for Rapid Retargeting and Precision Pointing of Small Satellites

    NASA Technical Reports Server (NTRS)

    Patankar, Kunal; Fitz-Coy, Norman; Roithmayr, Carlos M.

    2014-01-01

    This paper presents the design as well as characterization of a practical control moment gyroscope (CMG) based attitude control system (ACS) for small satellites in the 15-20 kilogram mass range performing rapid retargeting and precision pointing maneuvers. The paper focuses on the approach taken in the design of miniaturized CMGs while considering the constraints imposed by the use of commercial off-the-shelf (COTS) components as well as the size of the satellite. It is shown that a hybrid mode is more suitable for COTS based moment exchange actuators; a mode that uses the torque amplification of CMGs for rapid retargeting and direct torque capabilities of the flywheel motors for precision pointing. A simulation is provided to demonstrate on-orbit slew and pointing performance.

  17. DNA Nanotechnology for Precise Control over Drug Delivery and Gene Therapy.

    PubMed

    Angell, Chava; Xie, Sibai; Zhang, Liangfang; Chen, Yi

    2016-03-01

    Nanomedicine has been growing exponentially due to its enhanced drug targeting and reduced drug toxicity. It uses the interactions where nanotechnological components and biological systems communicate with each other to facilitate the delivery performance. At this scale, the physiochemical properties of delivery systems strongly affect their capacities. Among current delivery systems, DNA nanotechnology shows many advantages because of its unprecedented engineering abilities. Through molecular recognition, DNA nanotechnology can be used to construct a variety of nanostructures with precisely controllable size, shape, and surface chemistry, which can be appreciated in the delivery process. In this review, different approaches that are currently used for the construction of DNA nanostructures are reported. Further, the utilization of these DNA nanostructures with the well-defined parameters for the precise control in drug delivery and gene therapy is discussed. PMID:26725041

  18. Precise size control of hydrophobic gold nanoparticles using cooperative effect of refluxing ripening and seeding growth

    NASA Astrophysics Data System (ADS)

    Yang, Yun; Yan, Ya; Wang, Wei; Li, Jinru

    2008-04-01

    We describe herein a synthetic technology for precise size control of monodispersed hybrid gold nanoparticles, which combines seeding growth and digestive ripening. In this procedure, alkyl amines allow the solubilization and thermal reduction of HAuCl4 while 2.1 nm gold nanoparticles capped by thiol functions are used as seeds. By carefully controlling the HAuCl4/seeds ratio, highly monodisperse gold nanoparticles with various sizes (from 2.1 to 8.8 nm) can be generated. Variation of the alkyl amines as well as optimization of the growth procedure allows the precise tuning of particle size within a 0.5 nm range. On the basis of XPS and TEM studies, a mechanism for nanoparticle formation is proposed.

  19. Testing, characterization, and control of a multi-axis, high precision drive system for the Hobby-Eberly Telescope Wide Field Upgrade

    NASA Astrophysics Data System (ADS)

    Soukup, Ian M.; Beno, Joseph H.; Hill, Gary J.; Good, John M.; Penney, Charles E.; Beets, Timothy A.; Esguerra, Jorge D.; Hayes, Richard J.; Heisler, James T.; Zierer, Joseph J.; Wedeking, Gregory A.; Worthington, Michael S.; Wardell, Douglas R.; Booth, John A.; Cornell, Mark E.; Rafal, Marc D.

    2012-09-01

    A multi-axis, high precision drive system has been designed and developed for the Wide Field Upgrade to the Hobby- Eberly Telescope at McDonald Observatory. Design, performance and controls details will be of interest to designers of large scale, high precision robotic motion devices. The drive system positions the 20-ton star tracker to a precision of less than 5 microns along each axis and is capable of 4 meters of X/Y travel, 0.3 meters of hexapod actuator travel, and 46 degrees of rho rotation. The positioning accuracy of the new drive system is achieved through the use of highprecision drive hardware in addition to a meticulously tuned high-precision controller. A comprehensive understanding of the drive structure, disturbances, and drive behavior was necessary to develop the high-precision controller. Thorough testing has characterized manufacture defects, structural deflections, sensor error, and other parametric uncertainty. Positioning control through predictive algorithms that analytically compensate for measured disturbances has been developed as a result of drive testing and characterization. The drive structure and drive dynamics are described as well as key results discovered from testing and modeling. Controller techniques and development of the predictive algorithms are discussed. Performance results are included, illustrating recent performance of several axes of the drive system. This paper describes testing that occurred at the Center for Electromechanics in Austin Texas.

  20. Achieving process control through improved grinding techniques for ferrite materials

    SciTech Connect

    Bruce, J.

    1995-09-01

    In manufacturing soft ferrite materials the particle size of the raw material has a significant impact on the reactivity of calcination. The control of particle size distribution and final formulation at wet milling after calcining impacts the reactivity during sintering and the magnetic properties of the final product. This paper will deal with steps taken to improve process control during the grinding operations of raw material and calcine in soft ferrite production. Equipment modifications as well as changes to the grinding and material handling techniques will be included. All examples of process control and improvements will be supported by data.

  1. Debris control design achievements of the booster separation motors

    NASA Technical Reports Server (NTRS)

    Smith, G. W.; Chase, C. A.

    1985-01-01

    The stringent debris control requirements imposed on the design of the Space Shuttle booster separation motor are described along with the verification program implemented to ensure compliance with debris control objectives. The principal areas emphasized in the design and development of the Booster Separation Motor (BSM) relative to debris control were the propellant formulation and nozzle closures which protect the motors from aerodynamic heating and moisture. A description of the motor design requirements, the propellant formulation and verification program, and the nozzle closures design and verification are presented.

  2. Precise Ratiometric Control of Dual Drugs through a Single Macromolecule for Combination Therapy.

    PubMed

    Luo, Shiying; Gu, Ying; Zhang, Yuannian; Guo, Pei; Mukerabigwi, Jean Felix; Liu, Min; Lei, Shaojun; Cao, Yu; He, Hongxuan; Huang, Xueying

    2015-07-01

    A major challenge of combinatorial therapy is the unification of the pharmacokinetics and cellular uptake of various drug molecules with precise control of the dosage thereby maximizing the combined effects. To realize ratiometric delivery and synchronized release of different drugs from a single carrier, a novel approach was designed in this study to load dual drugs onto the macromolecular carrier with different molar ratio by covalently preconjugating dual drugs through peptide linkers to form drug conjugates. In contrast to loading individual types of drugs separately, these drug conjugates enable the loading of dual drugs onto the same carrier in a precisely controllable manner to reverse multidrug resistance (MDR) of human hepatoma (HepG2) cells. As a proof of concept, the synthesis and characterization of xyloglucan-mitomycin C/doxorubicin (XG-MMC/DOX) conjugates were demonstrated. This approach enabled MMC and DOX to be conjugated to the same polymeric carrier with precise control of drug dosage. The cytotoxicity and combinatorial effects were significantly improved compared to the cocktail mixtures of XG-MMC and XG-DOX as well as the individual conjugate of the mixture. Moreover, the results also showed that there was an optimum ratio of dual drugs showing the best cytotoxicity effect and greatest synergy among other tested polymeric conjugate formulations. PMID:26035636

  3. An active control strategy for achieving weak radiator structures

    SciTech Connect

    Naghshineh, K. . Acoustics and Radar Technology Lab.); Koopmann, G.H. . Center for Acoustics and Vibration)

    1994-01-01

    A general control strategy is presented for active suppression of total radiated sound power from harmonically excited structures based on the measurement of their response. Using the measured response of the structure together with knowledge of its structural mobility, and equivalent primary excitation force is found at discrete points along the structure. Using this equivalent primary force and performing a quadratic optimization of the power radiated form the structure, a set of control forces is found at selected points on the structure that results in minimum radiated sound power. A numerical example of this strategy is presented for a simply supported beam in a rigid baffle excited by a harmonic plane wave incident at an oblique angle. A comparison of the response of the beam with and without control forces shows a large reduction in the controlled response displacement magnitude. In addition, as the result of the action of the control forces, the magnitude of the wave number spectrum of the beam's response in the supersonic region is decreased substantially. The effect of the number and location of the actuators on reductions in sound power level is also studied. The actuators located at the anti-nodes of structural modes within the supersonic region together with those located near boundaries are found to be the most effective in controlling the radiation of sound from a structure.

  4. Design and control of a macro-micro robot for precise force applications

    NASA Technical Reports Server (NTRS)

    Wang, Yulun; Mangaser, Amante; Laby, Keith; Jordan, Steve; Wilson, Jeff

    1993-01-01

    Creating a robot which can delicately interact with its environment has been the goal of much research. Primarily two difficulties have made this goal hard to attain. The execution of control strategies which enable precise force manipulations are difficult to implement in real time because such algorithms have been too computationally complex for available controllers. Also, a robot mechanism which can quickly and precisely execute a force command is difficult to design. Actuation joints must be sufficiently stiff, frictionless, and lightweight so that desired torques can be accurately applied. This paper describes a robotic system which is capable of delicate manipulations. A modular high-performance multiprocessor control system was designed to provide sufficient compute power for executing advanced control methods. An 8 degree of freedom macro-micro mechanism was constructed to enable accurate tip forces. Control algorithms based on the impedance control method were derived, coded, and load balanced for maximum execution speed on the multiprocessor system. Delicate force tasks such as polishing, finishing, cleaning, and deburring, are the target applications of the robot.

  5. A liquid-delivery device that provides precise reward control for neurophysiological and behavioral experiments.

    PubMed

    Mitz, Andrew R

    2005-10-15

    Behavioral neurophysiology and other kinds of behavioral research often involve the delivery of liquid rewards to experimental subjects performing some kind of operant task. Available systems use gravity or pumps to deliver these fluids, but such methods are poorly suited to moment-to-moment control of the volume, timing, and type of fluid delivered. The design described here overcomes these limitations using an electronic control unit, a pressurized reservoir unit, and an electronically controlled solenoid. The control unit monitors reservoir pressure and provides precisely timed solenoid activation signals. It also stores calibration tables and does on-the-fly interpolation to support computer-controlled delivery calibrated directly in milliliters. The reservoir provides pressurized liquid to a solenoid mounted near the subject. Multiple solenoids, each supplied by a separate reservoir unit and control unit, can be stacked in close proximity to allow instantaneous selection of which liquid reward is delivered. The precision of droplet delivery was verified by weighing discharged droplets on a commercial analytical balance. PMID:16168492

  6. Achievement Goals and Emotions: The Mediational Roles of Perceived Progress, Control, and Value

    ERIC Educational Resources Information Center

    Hall, Nathan C.; Sampasivam, Lavanya; Muis, Krista R.; Ranellucci, John

    2016-01-01

    Background: The link between achievement goals and achievement emotions is well established; however, research exploring potential mediators of this relationship is lacking. The control-value theory of achievement emotions (Pekrun, 2006, "Educational Psychology Review," 18, 315) posits that perceptions of control and value mediate the…

  7. Achieving Acceptable Air Quality: Some Reflections on Controlling Vehicle Emissions

    NASA Astrophysics Data System (ADS)

    Calvert, J. G.; Heywood, J. B.; Sawyer, R. F.; Seinfeld, J. H.

    1993-07-01

    Motor vehicle emissions have been and are being controlled in an effort to abate urban air pollution. This article addresses the question: Will the vehicle exhaust emission control and fuel requirements in the 1990 Clean Air Act Amendments and the California Air Resources Board regulations on vehicles and fuels have a significant impact? The effective control of in-use vehicle emissions is the key to a solution to the motor vehicle part of the urban air pollution problem for the next decade or so. It is not necessary, except perhaps in Southern California, to implement extremely low new car emission standards before the end of the 20th century. Some of the proposed gasoline volatility and composition changes in reformulated gasoline will produce significant reductions in vehicle emissions (for example, reduced vapor pressure, sulfur, and light olefin and improved high end volatility), whereas others (such as substantial oxygenate addition and aromatics reduction) will not.

  8. Precise attoliter temperature control of nanopore sensors using a nanoplasmonic bullseye.

    PubMed

    Crick, Colin R; Albella, Pablo; Ng, Binghao; Ivanov, Aleksandar P; Roschuk, Tyler; Cecchini, Michael P; Bresme, Fernando; Maier, Stefan A; Edel, Joshua B

    2015-01-14

    Targeted temperature control in nanopores is greatly important in further understanding biological molecules. Such control would extend the range of examinable molecules and facilitate advanced analysis, including the characterization of temperature-dependent molecule conformations. The work presented within details well-defined plasmonic gold bullseye and silicon nitride nanopore membranes. The bullseye nanoantennae are designed and optimized using simulations and theoretical calculations for interaction with 632.8 nm laser light. Laser heating was monitored experimentally through nanopore conductance measurements. The precise heating of nanopores is demonstrated while minimizing the accumulation of heat in the surrounding membrane material. PMID:25467211

  9. Making Precise Antenna Reflectors For Millimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Sharp, G. Richard; Wanhainen, Joyce S.; Ketelsen, Dean A.

    1994-01-01

    In improved method of fabrication of precise, lightweight antenna reflectors for millimeter wavelengths, required precise contours of reflecting surfaces obtained by computer numberically controlled machining of surface layers bonded to lightweight, rigid structures. Achievable precision greater than that of older, more-expensive fabrication method involving multiple steps of low- and high-temperature molding, in which some accuracy lost at each step.

  10. Cognitive Control Predicts Academic Achievement in Kindergarten Children

    ERIC Educational Resources Information Center

    Coldren, Jeffrey T.

    2013-01-01

    Children's ability to shift behavior in response to changing environmental demands is critical for successful intellectual functioning. While the processes underlying the development of cognitive control have been thoroughly investigated, its functioning in an ecologically relevant setting such as school is less well understood. Given the alarming…

  11. ACHIEVING IRRIGATION RETURN FLOW QUALITY CONTROL THROUGH IMPROVED LEGAL SYSTEMS

    EPA Science Inventory

    The key to irrigated agricultural return flow quality control is proper utilization and management of the resource itself, and an accepted tool in out society is the law. This project is designed to develop legal alternatives that will facilitate the implementation of improved wa...

  12. High Precision Tracking Control based on Pseudo-Inverse Feedforward Control System for Next-Generation Optical Disks

    NASA Astrophysics Data System (ADS)

    Ogata, Tokoku; Nakazaki, Tatsuya; Sakimura, Naohide; Ohishi, Kiyoshi; Miyazaki, Toshimasa; Koide, Daiichi; Tokumaru, Haruki; Takano, Yoshimichi

    2012-08-01

    Optical disk drive systems must realize high-precision tracking control. For this purpose, we have already proposed a tracking control system that is composed of a high gain servo controller (HGSC) and a perfect tracking controller (PTC). The conventional feedforward tracking control system adequately suppresses the tracking error caused by track eccentricity. However, the PTC system in the conventional system is complicated. Therefore, the PTC system embedded on a digital signal processor (DSP) cannot realize fast sampling time and the conventional system has a speedup limitation in the optical disk tracking control system. Hence, in this paper, we propose a new high-speed and high-precision feedforward tracking control system that uses a pseudo-inverse matrix. The proposed system consists of the pseudo-inverse feedforward control (P-IFFC). The proposed system realizes simple and quick execution in a digital signal processor software servo. Our experimental results confirm that the proposed system effectively suppresses the tracking error under a condition of the 7200 rpm disk rotation speed of DVD+R. In addition, the conventional systems and the proposed system with a pseudo-inverse matrix are compared in terms of processing time and tracking error.

  13. Automated optogenetic feedback control for precise and robust regulation of gene expression and cell growth

    PubMed Central

    Milias-Argeitis, Andreas; Rullan, Marc; Aoki, Stephanie K.; Buchmann, Peter; Khammash, Mustafa

    2016-01-01

    Dynamic control of gene expression can have far-reaching implications for biotechnological applications and biological discovery. Thanks to the advantages of light, optogenetics has emerged as an ideal technology for this task. Current state-of-the-art methods for optical expression control fail to combine precision with repeatability and cannot withstand changing operating culture conditions. Here, we present a novel fully automatic experimental platform for the robust and precise long-term optogenetic regulation of protein production in liquid Escherichia coli cultures. Using a computer-controlled light-responsive two-component system, we accurately track prescribed dynamic green fluorescent protein expression profiles through the application of feedback control, and show that the system adapts to global perturbations such as nutrient and temperature changes. We demonstrate the efficacy and potential utility of our approach by placing a key metabolic enzyme under optogenetic control, thus enabling dynamic regulation of the culture growth rate with potential applications in bacterial physiology studies and biotechnology. PMID:27562138

  14. Automated optogenetic feedback control for precise and robust regulation of gene expression and cell growth.

    PubMed

    Milias-Argeitis, Andreas; Rullan, Marc; Aoki, Stephanie K; Buchmann, Peter; Khammash, Mustafa

    2016-01-01

    Dynamic control of gene expression can have far-reaching implications for biotechnological applications and biological discovery. Thanks to the advantages of light, optogenetics has emerged as an ideal technology for this task. Current state-of-the-art methods for optical expression control fail to combine precision with repeatability and cannot withstand changing operating culture conditions. Here, we present a novel fully automatic experimental platform for the robust and precise long-term optogenetic regulation of protein production in liquid Escherichia coli cultures. Using a computer-controlled light-responsive two-component system, we accurately track prescribed dynamic green fluorescent protein expression profiles through the application of feedback control, and show that the system adapts to global perturbations such as nutrient and temperature changes. We demonstrate the efficacy and potential utility of our approach by placing a key metabolic enzyme under optogenetic control, thus enabling dynamic regulation of the culture growth rate with potential applications in bacterial physiology studies and biotechnology. PMID:27562138

  15. Displacement sensor with controlled measuring force and its error analysis and precision verification

    NASA Astrophysics Data System (ADS)

    Yang, Liangen; Wang, Xuanze; Lv, Wei

    2011-05-01

    A displacement sensor with controlled measuring force and its error analysis and precision verification are discussed in this paper. The displacement sensor consists of an electric induction transducer with high resolution and a voice coil motor (VCM). The measuring principles, structure, method enlarging measuring range, signal process of the sensor are discussed. The main error sources such as parallelism error and incline of framework by unequal length of leaf springs, rigidity of measuring rods, shape error of stylus, friction between iron core and other parts, damping of leaf springs, variation of voltage, linearity of induction transducer, resolution and stability are analyzed. A measuring system for surface topography with large measuring range is constructed based on the displacement sensor and 2D moving platform. Measuring precision and stability of the measuring system is verified. Measuring force of the sensor in measurement process of surface topography can be controlled at μN level and hardly changes. It has been used in measurement of bearing ball, bullet mark, etc. It has measuring range up to 2mm and precision of nm level.

  16. Displacement sensor with controlled measuring force and its error analysis and precision verification

    NASA Astrophysics Data System (ADS)

    Yang, Liangen; Wang, Xuanze; Lv, Wei

    2010-12-01

    A displacement sensor with controlled measuring force and its error analysis and precision verification are discussed in this paper. The displacement sensor consists of an electric induction transducer with high resolution and a voice coil motor (VCM). The measuring principles, structure, method enlarging measuring range, signal process of the sensor are discussed. The main error sources such as parallelism error and incline of framework by unequal length of leaf springs, rigidity of measuring rods, shape error of stylus, friction between iron core and other parts, damping of leaf springs, variation of voltage, linearity of induction transducer, resolution and stability are analyzed. A measuring system for surface topography with large measuring range is constructed based on the displacement sensor and 2D moving platform. Measuring precision and stability of the measuring system is verified. Measuring force of the sensor in measurement process of surface topography can be controlled at μN level and hardly changes. It has been used in measurement of bearing ball, bullet mark, etc. It has measuring range up to 2mm and precision of nm level.

  17. Achievements in and Challenges of Tuberculosis Control in South Korea.

    PubMed

    Kim, Ji Han; Yim, Jae-Joon

    2015-11-01

    After the Korean War (1950-1953), nearly 6.5% of South Korea's population had active tuberculosis (TB). In response, South Korea implemented the National Tuberculosis Program in 1962. From 1965 to 1995, the prevalence of bacteriologically confirmed pulmonary TB in South Korea decreased from 940 to 219 cases per 100,000 population. Astounding economic growth might have contributed to this result; however, TB incidence in South Korea remains the highest among high-income countries. The rate of decrease in TB incidence seems to have slowed over the past 15 years. A demographic shift toward an older population, many of whom have latent TB and various concurrent conditions, is challenging TB control efforts in South Korea. The increasing number of immigrants also plays a part in the prolonged battle against TB. A historical review of TB in South Korea provides an opportunity to understand national TB control efforts that are applicable to other parts of the world. PMID:26485188

  18. A new approach to driving and controlling precision lasers for cold-atom science

    NASA Astrophysics Data System (ADS)

    Luey, Ben; Shugrue, Jeremy; Anderson, Mike

    2014-05-01

    Vescent's Integrated Control Electronics (ICE) Platform is a new approach to controlling and driving lasers and other electoral devices in complex atomic and optical experiments. By employing low-noise, high-bandwidth analog electronics with digital control, ICE combines the performance of analog design with the convenience of the digital world. Utilizing a simple USB COM port interface, ICE can easily be controlled via LabView, Python, or an FPGA. High-speed TTL inputs enable precise external timing or triggering. ICE is capable of generating complex timing internally, enabling ICE to drive an entire experiment or it can be directed by an external control program. The system is capable of controlling up to 8 unique ICE slave boards providing flexibility to tailor an assortment of electronics hardware to the needs of a specific experiment. Examples of ICE slave boards are: a current controller and peak-lock laser servo, a four channel temperature controller, a current controller and offset phase lock servo. A single ensemble can drive, stabilize, and frequency lock 3 lasers in addition to powering an optical amplifier, while still leaving 2 remaining slots for further control needs. Staff Scientist

  19. Piping inspection instrument carriage with precise and repeatable position control and location determination

    DOEpatents

    Hapstack, M.; Talarek, T.R.; Zollinger, W.T.; Heckendorn, F.M. II; Park, L.R.

    1994-02-15

    An instrument carriage for inspection of piping comprises front and rear leg assemblies for engaging the interior of the piping and supporting and centering the carriage therein, and an instrumentation arm carried by a shaft system running from the front to rear leg assemblies. The shaft system has a screw shaft for moving the arm axially and a spline gear for moving the arm azimuthally. The arm has a pair of air cylinders that raise and lower a plate in the radial direction. On the plate are probes including an eddy current probe and an ultrasonic testing probe. The ultrasonic testing probe is capable of spinning 360[degree] about its axis. The instrument carriage uses servo motors and pressurized air cylinders for precise actuation of instrument components and precise, repeatable actuation of position control mechanisms. 8 figures.

  20. Piping inspection instrument carriage with precise and repeatable position control and location determination

    DOEpatents

    Hapstack, Mark; Talarek, Ted R.; Zollinger, W. Thor; Heckendorn, II, Frank M.; Park, Larry R.

    1994-01-01

    An instrument carriage for inspection of piping comprises front and rear leg assemblies for engaging the interior of the piping and supporting and centering the carriage therein, and an instrumentation arm carried by a shaft system running from the front to rear leg assemblies. The shaft system has a screw shaft for moving the arm axially and a spline gear for moving the arm azimuthally. The arm has a pair of air cylinders that raise and lower a plate in the radial direction. On the plate are probes including an eddy current probe and an ultrasonic testing probe. The ultrasonic testing probe is capable of spinning 360.degree. about its axis. The instrument carriage uses servo motors and pressurized air cylinders for precise actuation of instrument components and precise, repeatable actuation of position control mechanisms.

  1. Can Chemical Mouthwash Agents Achieve Plaque/Gingivitis Control?

    PubMed

    Van der Weijden, Fridus A; Van der Sluijs, Eveline; Ciancio, Sebastian G; Slot, Dagmar E

    2015-10-01

    Also note that structured abstracts are not allowed per journal style: What is the effect of a mouthwash containing various active chemical ingredients on plaque control and managing gingivitis in adults based on evidence gathered from existing systematic reviews? The summarized evidence suggests that mouthwashes containing chlorhexidine(CHX) and essential oils (EO) had a large effect supported by a strong body of evidence. Also there was strong evidence for a moderate effect of cetylpyridinium chloride(CPC). Evidence suggests that a CHX mouthwash is the first choice, the most reliable alternative is EO. No difference between CHX and EO with respect to gingivitis was observed. PMID:26427569

  2. Achievements in and Challenges of Tuberculosis Control in South Korea

    PubMed Central

    Kim, Ji Han

    2015-01-01

    After the Korean War (1950–1953), nearly 6.5% of South Korea’s population had active tuberculosis (TB). In response, South Korea implemented the National Tuberculosis Program in 1962. From 1965 to 1995, the prevalence of bacteriologically confirmed pulmonary TB in South Korea decreased from 940 to 219 cases per 100,000 population. Astounding economic growth might have contributed to this result; however, TB incidence in South Korea remains the highest among high-income countries. The rate of decrease in TB incidence seems to have slowed over the past 15 years. A demographic shift toward an older population, many of whom have latent TB and various concurrent conditions, is challenging TB control efforts in South Korea. The increasing number of immigrants also plays a part in the prolonged battle against TB. A historical review of TB in South Korea provides an opportunity to understand national TB control efforts that are applicable to other parts of the world. PMID:26485188

  3. Muscle function in avian flight: achieving power and control

    PubMed Central

    Biewener, Andrew A.

    2011-01-01

    Flapping flight places strenuous requirements on the physiological performance of an animal. Bird flight muscles, particularly at smaller body sizes, generally contract at high frequencies and do substantial work in order to produce the aerodynamic power needed to support the animal's weight in the air and to overcome drag. This is in contrast to terrestrial locomotion, which offers mechanisms for minimizing energy losses associated with body movement combined with elastic energy savings to reduce the skeletal muscles' work requirements. Muscles also produce substantial power during swimming, but this is mainly to overcome body drag rather than to support the animal's weight. Here, I review the function and architecture of key flight muscles related to how these muscles contribute to producing the power required for flapping flight, how the muscles are recruited to control wing motion and how they are used in manoeuvring. An emergent property of the primary flight muscles, consistent with their need to produce considerable work by moving the wings through large excursions during each wing stroke, is that the pectoralis and supracoracoideus muscles shorten over a large fraction of their resting fibre length (33–42%). Both muscles are activated while being lengthened or undergoing nearly isometric force development, enhancing the work they perform during subsequent shortening. Two smaller muscles, the triceps and biceps, operate over a smaller range of contractile strains (12–23%), reflecting their role in controlling wing shape through elbow flexion and extension. Remarkably, pigeons adjust their wing stroke plane mainly via changes in whole-body pitch during take-off and landing, relative to level flight, allowing their wing muscles to operate with little change in activation timing, strain magnitude and pattern. PMID:21502121

  4. Precision Metabolic Engineering: the Design of Responsive, Selective, and Controllable Metabolic Systems

    PubMed Central

    McNerney, Monica P.; Watstein, Daniel M.; Styczynski, Mark P.

    2015-01-01

    Metabolic engineering is generally focused on static optimization of cells to maximize production of a desired product, though recently dynamic metabolic engineering has explored how metabolic programs can be varied over time to improve titer. However, these are not the only types of applications where metabolic engineering could make a significant impact. Here, we discuss a new conceptual framework, termed “precision metabolic engineering,” involving the design and engineering of systems that make different products in response to different signals. Rather than focusing on maximizing titer, these types of applications typically have three hallmarks: sensing signals that determine the desired metabolic target, completely directing metabolic flux in response to those signals, and producing sharp responses at specific signal thresholds. In this review, we will first discuss and provide examples of precision metabolic engineering. We will then discuss each of these hallmarks and identify which existing metabolic engineering methods can be applied to accomplish those tasks, as well as some of their shortcomings. Ultimately, precise control of metabolic systems has the potential to enable a host of new metabolic engineering and synthetic biology applications for any problem where flexibility of response to an external signal could be useful. PMID:26189665

  5. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata

    NASA Astrophysics Data System (ADS)

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash

    2013-11-01

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A&M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase/Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata.

  6. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata

    SciTech Connect

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash

    2013-11-15

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A and M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9–27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase/Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata.

  7. Children's effortful control and academic achievement: do relational peer victimization and classroom participation operate as mediators?

    PubMed

    Valiente, Carlos; Swanson, Jodi; Lemery-Chalfant, Kathryn; Berger, Rebecca H

    2014-08-01

    Given that early academic achievement is related to numerous developmental outcomes, understanding processes that promote early success in school is important. This study was designed to clarify how students' (N=291; M age in fall of kindergarten=5.66 years, SD=0.39 year) effortful control, relational peer victimization, and classroom participation relate to achievement, as students progress from kindergarten to first grade. Effortful control and achievement were assessed in kindergarten, classroom participation and relational peer victimization were assessed in the fall of first grade, and achievement was reassessed in the spring of first grade. Classroom participation, but not relational peer victimization, mediated relations between effortful control and first grade standardized and teacher-rated achievement, controlling for kindergarten achievement. Findings suggest that aspects of classroom participation, such as the ability to work independently, may be useful targets of intervention for enhancing academic achievement in young children. PMID:25107413

  8. Datum maintenance of the main Egyptian geodetic control networks by utilizing Precise Point Positioning "PPP" technique

    NASA Astrophysics Data System (ADS)

    Rabah, Mostafa; Elmewafey, Mahmoud; Farahan, Magda H.

    2016-06-01

    A geodetic control network is the wire-frame or the skeleton on which continuous and consistent mapping, Geographic Information Systems (GIS), and surveys are based. Traditionally, geodetic control points are established as permanent physical monuments placed in the ground and precisely marked, located, and documented. With the development of satellite surveying methods and their availability and high degree of accuracy, a geodetic control network could be established by using GNSS and referred to an international terrestrial reference frame used as a three-dimensional geocentric reference system for a country. Based on this concept, in 1992, the Egypt Survey Authority (ESA) established two networks, namely High Accuracy Reference Network (HARN) and the National Agricultural Cadastral Network (NACN). To transfer the International Terrestrial Reference Frame to the HARN, the HARN was connected with four IGS stations. The processing results were 1:10,000,000 (Order A) for HARN and 1:1,000,000 (Order B) for NACN relative network accuracy standard between stations defined in ITRF1994 Epoch1996. Since 1996, ESA did not perform any updating or maintaining works for these networks. To see how non-performing maintenance degrading the values of the HARN and NACN, the available HARN and NACN stations in the Nile Delta were observed. The Processing of the tested part was done by CSRS-PPP Service based on utilizing Precise Point Positioning "PPP" and Trimble Business Center "TBC". The study shows the feasibility of Precise Point Positioning in updating the absolute positioning of the HARN network and its role in updating the reference frame (ITRF). The study also confirmed the necessity of the absent role of datum maintenance of Egypt networks.

  9. Versatile, kinetically controlled, high precision electrohydrodynamic writing of micro/nanofibers

    PubMed Central

    Huang, YongAn; Duan, Yongqing; Ding, Yajiang; Bu, Ningbin; Pan, Yanqiao; Lu, Nanshu; Yin, Zhouping

    2014-01-01

    Direct writing of hierarchical micro/nanofibers have recently gained popularity in flexible/stretchable electronics due to its low cost, simple process and high throughput. A kinetically controlled mechanoelectrospinning (MES) is developed to directly write diversified hierarchical micro/nanofibers in a continuous and programmable manner. Unlike conventional near-field electrospinning, our MES method introduces a mechanical drawing force, to simultaneously enhance the positioning accuracy and morphology controllability. The MES is predominantly controlled by the substrate speed, the nozzle-to-substrate distance, and the applied voltage. As a demonstration, smooth straight, serpentine, self-similar, and bead-on-string structures are direct-written on silicon/elastomer substrates with a resolution of 200 nm. It is believed that MES can promote the low-cost, high precision fabrication of flexible/stretchable electronics or enable the direct writing of the sacrificial structures for nanoscale lithography. PMID:25091829

  10. Two-stage rule-based precision positioning control of a piezoelectrically actuated table

    NASA Astrophysics Data System (ADS)

    Kuo, W. M.; Tarng, Y. S.; Nian, C. Y.; Nurhadi, H.

    2010-05-01

    This article proposes a two-stage rule-based precision positioning control method for the linear piezoelectrically actuated table (LPAT). During coarse-tuning stage, the LPAT is actuated by coarse voltages towards the target of 20 µm at a higher velocity; and during fine-tuning stage, it is driven by fine voltage steadily and accurately to reach the target position. The rule-based method is employed to establish the control rules for the voltages and displacements of the two stages using statistical methods. The experimental results demonstrate that the proposed control method can reach steady state quickly, and the steady-state error can be reduced to less than or equal to 0.02 µm for small travel (±0.1 µm) and large travel (±20 mm).

  11. Pupil tracking optical coherence tomography for precise control of pupil entry position

    PubMed Central

    Carrasco-Zevallos, Oscar; Nankivil, Derek; Keller, Brenton; Viehland, Christian; Lujan, Brandon J.; Izatt, Joseph A.

    2015-01-01

    To maximize the collection efficiency of back-scattered light, and to minimize aberrations and vignetting, the lateral position of the scan pivot of an optical coherence tomography (OCT) retinal scanner should be imaged to the center of the ocular pupil. Additionally, several retinal structures including Henle’s Fiber Layer (HFL) exhibit reflectivities that depend on illumination angle, which can be controlled by varying the pupil entry position of the OCT beam. In this work, we describe an automated method for controlling the lateral pupil entry position in retinal OCT by utilizing pupil tracking in conjunction with a 2D fast steering mirror placed conjugate to the retinal plane. We demonstrate that pupil tracking prevents lateral motion artifacts from impeding desired pupil entry locations, and enables precise pupil entry positioning and therefore control of the illumination angle of incidence at the retinal plane. We use our prototype pupil tracking OCT system to directly visualize the obliquely oriented HFL. PMID:26417510

  12. High precision digital control LED spot light source used to calibrate camera

    NASA Astrophysics Data System (ADS)

    Du, Boyu; Xu, Xiping; Liu, Yang

    2015-04-01

    This paper introduces a method of using LED point light source as the camera calibration light. According to the characteristics of the LED point light source, the constant current source is used to provide the necessary current and the illuminometer is used to measure the luminance of the LED point light source. The constant current source is controlled by ARM MCU and exchange data with the host computer though the mode of serial communications. The PC is used as the host computer, it adjust the current according to the luminance of the LED point light source until the luminance achieve the anticipated value. By experimental analysis, we found that the LED point light source can achieve the desired requirements as the calibration light source, and the accuracy is quite better that achieve the desired effect and it can adaptive control the luminance of LED well. The system is convenient and flexible, and its performance is stable and reliable.

  13. UAV-Based L-Band SAR with Precision Flight Path Control

    NASA Technical Reports Server (NTRS)

    Madsen, Soren N.; Hensley, Scott; Wheeler, Kevin; Sadowy, Greg; Miller, Tim; Muellerschoen, Ron; Lou, Yunling; Rosen, Paul

    2004-01-01

    NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also know as differential interferometric measurements. Differential interferometry can provide key displacement measurements, important for the scientific studies of Earthquakes and volcanoes. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The radar will be designed to operate on a UAV (Unmanned Arial Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus build by Scaled Composites. The application requires control of the flight path to within a 10 meter tube to support repeat track and formation flying measurements. The design is fully polarimetric with an 80 MHz bandwidth (2 meter range resolution) and 16 kilometer range swath. The antenna is an electronically steered array to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. The system will nominally operate at 45,000 ft. The program started out as a Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

  14. Polarisation control through an optical feedback technique and its application in precise measurements

    PubMed Central

    Chen, Wenxue; Zhang, Shulian; Long, Xingwu

    2013-01-01

    We present an anisotropic optical feedback technique for controlling light polarisation. The technique is based on the principle that the effective gain of a light mode is modulated by the magnitude of the anisotropic feedback. A new physical model that integrates Lamb's semi-classical theory and a model of the equivalent cavity of a Fabry-Perot interferometer is developed to reveal the physical nature of this technique. We use this technique to measure the phase retardation, optical axis, angle, thickness and refractive index with a high precision of λ/1380, 0.01°, 0.002°, 59 nm and 0.0006, respectively. PMID:23771164

  15. Correction for Self-Heating When Using Thermometers as Heaters in Precision Control Applications

    NASA Technical Reports Server (NTRS)

    Ressler, Michael E.; Cho, Hyung J.; Sukhatme, Kalyani G.

    2011-01-01

    In precision control applications, thermometers have temperature-dependent electrical resistance with germanium or other semiconductor material thermistors, diodes, metal film and wire, or carbon film resistors. Because resistance readout requires excitation current flowing through the sensor, there is always ohmic heating that leads to a temperature difference between the sensing element and the monitored object. In this work, a thermistor can be operated as a thermometer and a heater, simultaneously, by continuously measuring the excitation current and the corresponding voltage. This work involves a method of temperature readout where the temperature offset due to self-heating is subtracted exactly.

  16. A High Precision Scanning Control System For A VUV Fourier Transform Spectrometer

    SciTech Connect

    De Oliveira, N.; Nahon, L.; Polack, F.; Joyeux, D.; Phalippou, D.; Rodier, J. C.; Vervloeet, M.

    2007-01-19

    A VUV Fourier transform spectrometer based on a wavefront division interferometer has been built. Our ultimate goal is to provide a high resolution absorption spectrometer in the 140 - 40 nm range using the new third generation French synchrotron source Soleil as the background continuum. Here, we present the design and latest performance of the instrument scanning control system. It is based on multiple reflections of a monomode, frequency-stabilized HeNe laser between two plane mirrors allowing the required sensitivity on the displacement of the interferometer mobile arm. The experimental results on the sampling precision show an rms error below 5 nm for a travel length of 7.5 mm.

  17. Why achievement motivation predicts success in business but failure in politics: the importance of personal control.

    PubMed

    Winter, David G

    2010-12-01

    Several decades of research have established that implicit achievement motivation (n Achievement) is associated with success in business, particularly in entrepreneurial or sales roles. However, several political psychology studies have shown that achievement motivation is not associated with success in politics; rather, implicit power motivation often predicts political success. Having versus lacking control may be a key difference between business and politics. Case studies suggest that achievement-motivated U.S. presidents and other world leaders often become frustrated and thereby fail because of lack of control, whereas power-motivated presidents develop ways to work with this inherent feature of politics. A reevaluation of previous research suggests that, in fact, relationships between achievement motivation and business success only occur when control is high. The theme of control is also prominent in the development of achievement motivation. Cross-national data are also consistent with this analysis: In democratic industrialized countries, national levels of achievement motivation are associated with strong executive control. In countries with low opportunity for education (thus fewer opportunities to develop a sense of personal control), achievement motivation is associated with internal violence. Many of these manifestations of frustrated achievement motivation in politics resemble authoritarianism. This conclusion is tested by data from a longitudinal study of 113 male college students, showing that high initial achievement motivation combined with frustrated desires for control is related to increases in authoritarianism (F-scale scores) during the college years. Implications for the psychology of leadership and practical politics are discussed. PMID:21039527

  18. Highly Precise Rotational Speed Control by a Hybrid of PLL and Repetitive Control

    NASA Astrophysics Data System (ADS)

    Machida, Hidekazu; Inoue, Takashi; Kobayashi, Fuminori

    PLL speed control system has excellent ‘macroscopic’, or long-term, steadiness. However, ‘microscopic’ speed fluctuation is another important issue. It is called ‘cogging,’ caused by electro-magnetic structural property of motor. Although repetitive control is useful for reducing such fluctuation, stability condition is hard to be satisfied for PLL which inevitably includes integrator. In this article, we propose a D repetitive controller to ease this condition. Rather simple implementation with an FPGA and effective experimental results revealing 60% reduction in fluctuation are shown.

  19. Testing of an End-Point Control Unit Designed to Enable Precision Control of Manipulator-Coupled Spacecraft

    NASA Technical Reports Server (NTRS)

    Montgomery, Raymond C.; Ghosh, Dave; Tobbe, Patrick A.; Weathers, John M.; Manouchehri, Davoud; Lindsay, Thomas S.

    1994-01-01

    This paper presents an end-point control concept designed to enable precision telerobotic control of manipulator-coupled spacecraft. The concept employs a hardware unit (end-point control unit EPCU) that is positioned between the end-effector of the Space Shuttle Remote Manipulator System and the payload. Features of the unit are active compliance (control of the displacement between the end-effector and the payload), to allow precision control of payload motions, and inertial load relief, to prevent the transmission of loads between the end-effector and the payload. This paper presents the concept and studies the active compliance feature using a simulation and hardware. Results of the simulation show the effectiveness of the EPCU in smoothing the motion of the payload. Results are presented from initial, limited tests of a laboratory hardware unit on a robotic arm testbed at the l Space Flight Center. Tracking performance of the arm in a constant speed automated retraction and extension maneuver of a heavy payload with and without the unit active is compared for the design speed and higher speeds. Simultaneous load reduction and tracking performance are demonstrated using the EPCU.

  20. Approaches for achieving long-term accuracy and precision of δ18O and δ2H for waters analyzed using laser absorption spectrometers.

    PubMed

    Wassenaar, Leonard I; Coplen, Tyler B; Aggarwal, Pradeep K

    2014-01-21

    The measurement of δ(2)H and δ(18)O in water samples by laser absorption spectroscopy (LAS) are adopted increasingly in hydrologic and environmental studies. Although LAS instrumentation is easy to use, its incorporation into laboratory operations is not as easy, owing to extensive offline data manipulation required for outlier detection, derivation and application of algorithms to correct for between-sample memory, correcting for linear and nonlinear instrumental drift, VSMOW-SLAP scale normalization, and in maintaining long-term QA/QC audits. Here we propose a series of standardized water-isotope LAS performance tests and routine sample analysis templates, recommended procedural guidelines, and new data processing software (LIMS for Lasers) that altogether enables new and current LAS users to achieve and sustain long-term δ(2)H and δ(18)O accuracy and precision for these important isotopic assays. PMID:24328223

  1. Achieving glycemic control in young children with type 1 diabetes: approaches, pitfalls and new technologies.

    PubMed

    Gruppuso, Philip A

    2003-04-01

    Advances in technologies for insulin administrations, glucose monitoring, development of an artificial pancreas and cell-based therapy will ultimately have a profound effect on the lives of people wit diabetes. There is both current success and substantial promise, indicating that these approches may offer, for the first time, real potential for achieving euglycemia without hypoglycemia. Given the physiological and psychosocial impact of type 1 diabetes in young children, this group of patients and their parents stand to gain especially great benefit from these developments. However, the potential for improvements in the mangement of diabetes in young children based on available technologies should not be overlooked and should be effectively utilized as the standard for patient care. Only twenty years ago blood glucose reagent strips were first coming into routine use. Current meters have greatly reduced the amount of blood required ( now less than 1 microliter for many meters) and greatly imporved precision. The advent modified, recombinant insulins, which became available only in the last several years, allows for an insulin regimen to better match the absorption of dietary carbohydrate. All technologies have improved our ability to attain glycemic control, thereby reducing the risk of long-term complication in even our youngest patients. PMID:12751364

  2. Simple and Reliable Fabrication of Bioinspired Mushroom-Shaped Micropillars with Precisely Controlled Tip Geometries.

    PubMed

    Yi, Hoon; Kang, Minsu; Kwak, Moon Kyu; Jeong, Hoon Eui

    2016-08-31

    We present a simple yet scalable method with detailed process protocols for fabricating dry adhesives with mushroom-shaped micropillars of controlled tip geometries. The method involves using photo-lithography with a bilayer stack combining SU-8 and lift-off resist, and subsequent replica molding process. This approach utilizes widely used and commercially available materials and can thus be used to generate mushroom-shaped micropillars with precisely controlled tip diameters and thicknesses in a simple, reproducible, and cost-effective manner. The fabricated mushroom-shaped micropillar arrays exhibited highly different tendencies in adhesion strength and repeatability depending on tip geometries, such as tip diameter and thickness, thereby demonstrating the importance of precise tunability of tip geometry of micropillars. The fabricated dry adhesives with optimized tip geometries not only exhibited strong pull-off strength of up to ∼34.8 N cm(-2) on the Si surface but also showed high durability. By contrast, dry adhesives with nonoptimized tips displayed low pull-off strength of ∼3.6 N cm(-2) and poor durability. PMID:27548917

  3. Abdicating power for control: a precision timing strategy to modulate function of flight power muscles

    PubMed Central

    Sponberg, S.; Daniel, T. L.

    2012-01-01

    Muscles driving rhythmic locomotion typically show strong dependence of power on the timing or phase of activation. This is particularly true in insects' main flight muscles, canonical examples of muscles thought to have a dedicated power function. However, in the moth (Manduca sexta), these muscles normally activate at a phase where the instantaneous slope of the power–phase curve is steep and well below maximum power. We provide four lines of evidence demonstrating that, contrary to the current paradigm, the moth's nervous system establishes significant control authority in these muscles through precise timing modulation: (i) left–right pairs of flight muscles normally fire precisely, within 0.5–0.6 ms of each other; (ii) during a yawing optomotor response, left—right muscle timing differences shift throughout a wider 8 ms timing window, enabling at least a 50 per cent left–right power differential; (iii) timing differences correlate with turning torque; and (iv) the downstroke power muscles alone causally account for 47 per cent of turning torque. To establish (iv), we altered muscle activation during intact behaviour by stimulating individual muscle potentials to impose left—right timing differences. Because many organisms also have muscles operating with high power–phase gains (Δpower/Δphase), this motor control strategy may be ubiquitous in locomotor systems. PMID:22833272

  4. High-Precision Shape Control of In-Space Deployable Large Membrane/Thin-Shell Reflectors

    NASA Technical Reports Server (NTRS)

    Watkins, Ronald; Goebel, Dan; Hofer, Richard

    2010-01-01

    This innovation has been developed to improve the resolutions of future spacebased active and passive microwave antennas for earth-science remote sensing missions by maintaining surface figure precisions of large membrane/thin-shell reflectors during orbiting. The intention is for these sensing instruments to be deployable at orbit altitudes one or two orders of magnitude higher than Low Earth Orbit (LEO), but still being able to acquire measurements at spatial resolution and sensitivity similar to those of LEO. Because active and passive microwave remote sensors are able to penetrate through clouds to acquire vertical profile measurements of geophysical parameters, it is desirable to elevate them to the higher orbits to obtain orbital geometries that offer large spatial coverage and more frequent observations. This capability is essential for monitoring and for detailed understanding of the life cycles of natural hazards, such as hurricanes, tropical storms, flash floods, and tsunamis. Major components of this high-precision antenna-surface-control system include a membrane/thin shell reflector, a metrology sensor, a controller, actuators, and corresponding power amplifier and signal conditioning electronics (see figure). Actuators are attached to the back of the reflector to produce contraction/ expansion forces to adjust the shape of the thin-material reflector. The wavefront-sensing metrology system continuously measures the surface figure of the reflector, converts the surface figure to digital data and feeds the data to the controller. The controller determines the control parameters and generates commands to the actuator system. The flexible, piezoelectric polymer actuators are thus activated, providing the control forces needed to correct any distortions that exist in the reflector surface. Piezoelectric polymer actuators are very thin and flexible. They can be implemented on the back of the membrane/thin-shell reflector without introducing significant

  5. Piezoelectric Polymers Actuators for Precise Shape Control of Large Scale Space Antennas

    NASA Technical Reports Server (NTRS)

    Chen, Qin; Natale, Don; Neese, Bret; Ren, Kailiang; Lin, Minren; Zhang, Q. M.; Pattom, Matthew; Wang, K. W.; Fang, Houfei; Im, Eastwood

    2007-01-01

    Extremely large, lightweight, in-space deployable active and passive microwave antennas are demanded by future space missions. This paper investigates the development of PVDF based piezopolymer actuators for controlling the surface accuracy of a membrane reflector. Uniaxially stretched PVDF films were poled using an electrodeless method which yielded high quality poled piezofilms required for this application. To further improve the piezoperformance of piezopolymers, several PVDF based copolymers were examined. It was found that one of them exhibits nearly three times improvement in the in-plane piezoresponse compared with PVDF and P(VDF-TrFE) piezopolymers. Preliminary experimental results indicate that these flexible actuators are very promising in controlling precisely the shape of the space reflectors.

  6. High-precision control of LSRM based X-Y table for industrial applications.

    PubMed

    Pan, J F; Cheung, Norbert C; Zou, Yu

    2013-01-01

    The design of an X-Y table applying direct-drive linear switched reluctance motor (LSRM) principle is proposed in this paper. The proposed X-Y table has the characteristics of low cost, simple and stable mechanical structure. After the design procedure is introduced, an adaptive position control method based on online parameter identification and pole-placement regulation scheme is developed for the X-Y table. Experimental results prove the feasibility and its priority over a traditional PID controller with better dynamic response, static performance and robustness to disturbances. It is expected that the novel two-dimensional direct-drive system find its applications in high-precision manufacture area. PMID:22981303

  7. Relations among Peer Acceptance, Inhibitory Control, and Math Achievement in Early Adolescence

    ERIC Educational Resources Information Center

    Oberle, Eva; Schonert-Reichl, Kimberly A.

    2013-01-01

    This study examined relations among peer acceptance, inhibitory control, and math achievement in ninety-nine 4th and 5th grade early adolescents. Teachers rated students on peer acceptance and students completed a computerized executive function task assessing inhibitory control. Math achievement was assessed via end of year math grades. Results…

  8. Criterion-Related Validity of the Nowicki-Strickland Locus of Control Scale with Academic Achievement.

    ERIC Educational Resources Information Center

    Nunn, Gary D.; And Others

    1986-01-01

    Investigated the relationships between student locus of control and academic achievement in grades five through eight. The Nowicki-Strickland Locus of Control Scale (NSLOCS) was used to measure motivation, and the Iowa Tests of Basic Skills (ITBS) to assess academic achievement. Results indicated moderate inverse relationships between level of…

  9. Moving the Achievement Goal Approach One Step Forward: Toward a Systematic Examination of the Autonomous and Controlled Reasons Underlying Achievement Goals

    ERIC Educational Resources Information Center

    Vansteenkiste, Maarten; Lens, Willy; Elliot, Andrew J.; Soenens, Bart; Mouratidis, Athanasios

    2014-01-01

    An important recent development in the achievement goal literature is to define achievement goals strictly as aims. In this overview, we argue that this restrictive definition of achievement goals paves the way for a systematic consideration of the autonomous and controlled reasons underlying individuals' achievement goals, a distinction…

  10. High precision in Raman frequency achieved using real-time calibration with a neon emission line: application to three-dimensional stress mapping observations.

    PubMed

    Odake, Shoko; Fukura, Satoshi; Kagi, Hiroyuki

    2008-10-01

    A three-dimensional (3D) Raman mapping system with a real-time calibration function was developed for detecting stress distributions in solid materials from subtle frequency shifts in Raman spectra. An atomic emission line of neon at 918.3 cm(-1) when excited at 514.5 nm was used as a wavenumber standard. An emission spectrum of neon and a Raman spectrum from a sample were introduced into a single polychromator using a bifurcated optical fiber. These two spectra were recorded simultaneously on a charge-coupled device (CCD) detector using double-track mode. Energy deviation induced by the fluctuation of laboratory temperature, etc., was removed effectively using the neon emission line. High stability during long measurements was achieved. By applying curve fitting, positions of the Raman line were determined with precision of about 0.05 cm(-1). The present system was applied to measurements of residual pressure around mineral inclusions in a natural diamond: 3D stress mapping was achieved. PMID:18926016

  11. Less precise motor control leads to increased agonist-antagonist muscle activation during stick balancing.

    PubMed

    Reeves, N Peter; Popovich, John M; Vijayanagar, Vilok; Pathak, Pramod K

    2016-06-01

    Human motor control has constraints in terms of its responsiveness, which limit its ability to successfully perform tasks. In a previous study, it was shown that the ability to balance an upright stick became progressively more challenging as the natural frequency (angular velocity without control) of the stick increased. Furthermore, forearm and trunk agonist and antagonist muscle activation increased as the natural frequency of the stick increased, providing evidence that the central nervous system produces agonist-antagonist muscle activation to match task dynamics. In the present study, visual feedback of the stick position was influenced by changing where subject focused on the stick during stick balancing. It was hypothesized that a lower focal height would degrade motor control (more uncertainty in tracking stick position), thus making balancing more challenging. The probability of successfully balancing the stick at four different focal heights was determined along with the average angular velocity of the stick. Electromyographic signals from forearm and trunk muscles were also recorded. As expected, the probability of successfully balancing the stick decreased and the average angular velocity of the stick increased as subjects focused lower on the stick. In addition, changes in the level of agonist and antagonist muscle activation in the forearm and trunk was linearly related to changes in the angular velocity of the stick during balancing. One possible explanation for this is that the central nervous system increases muscle activation to account for less precise motor control, possibly to improve the responsiveness of human motor control. PMID:27010497

  12. Integration of near-field probes and photonic crystal nanocavities for precise and low-loss resonance control

    NASA Astrophysics Data System (ADS)

    Chew, Xiongyeu; Zhou, Guangya; Chau, Fook Siong

    2011-03-01

    Research interest for silicon nanophotonics is a topic of heavy interest currently due to the requirements for high density communications of integrated devices with small footprints in the semiconductor industry. Silicon photonic crystals (PhC) are nanoscale subwavelength periodic structures that possess the capability to induce strong interaction between light and matter. PhC nanocavities utilizes the photonic bandgap effect to trap certain frequencies of light within a small confined region for a diverse range of applications such as enhancement and suppression of spontaneous emission, efficient and compact lasers, add/drop multiplexers, optical filters and sensing etc. In this paper, we describe a mechanically-perturbative near-field probe with a special design shape to achieve low-loss and precise resonance control of PhC nanocavities. One-dimensional (1D) PhC are chosen for our study due to the ease of integrating with low-loss SOI waveguide technology and easy integration with nanomechanical structures. Sub-micron microelectromechanical systems (MEMS/NEMS) technology is introduced as an ideal integration platform with such near-field probe designs due to its capabilities to accurately control fine displacements without the need of bulky equipment such as atomic force microscopy (AFM), scanning near field microscope (SNOM) or highly sensitive piezo-controlled micromanipulator stages. We propose that such near-field probe designs are capable of achieving large resonance spectral shift of up to few nm with high re-configurability, highly accurate actuation displacements, low power consumption, and portability. In this work, we propose an approach utilizing numerical methods to study and characterize the electromagnetic interaction between PhC nanocavities and nanomechanically displaced near-field nano-probes.

  13. Adaptive sliding mode control on inner axis for high precision flight motion simulator

    NASA Astrophysics Data System (ADS)

    Fu, Yongling; Niu, Jianjun; Wang, Yan

    2008-10-01

    Discrete adaptive sliding mode control (ASMC) with exponential reaching law is proposed to alleviate the influence of the factors such as the periodical fluctuation torque of motor, nonlinear friction, and other disturbance which will deteriorate the tracking performance of a DC torque motor driven inner axis for a high precision flight motion simulator, considering the limited compensating ability of the ASMC for these uncertainty, an equivalent friction advance compensator based on Stribeck model is also presented for extra-low speed servo of the system. Firstly, the way direct using the available parts of the inner axis itself to ascertain the parameters for Stribeck model is listed. Secondly, adaptive approach is used to overcome the difficulty of choice the key parameter for exponential reaching law, and the stability of the algorithm is analyzed. Lastly, comparable experiments are carried out to verify the valid of the combined approach. The experiments results show with a stable 0.00006°/s speed response, 95% of time the tracking error is within 0.0002°, other servos such as sine wave tracking are also with high precision.

  14. Comparison study on disturbance estimation techniques in precise slow motion control

    NASA Astrophysics Data System (ADS)

    Fan, S.; Nagamune, R.; Altintas, Y.; Fan, D.; Zhang, Z.

    2010-08-01

    Precise low speed motion control is important for the industrial applications of both micro-milling machine tool feed drives and electro-optical tracking servo systems. It calls for precise position and instantaneous velocity measurement and disturbance, which involves direct drive motor force ripple, guide way friction and cutting force etc., estimation. This paper presents a comparison study on dynamic response and noise rejection performance of three existing disturbance estimation techniques, including the time-delayed estimators, the state augmented Kalman Filters and the conventional disturbance observers. The design technique essentials of these three disturbance estimators are introduced. For designing time-delayed estimators, it is proposed to substitute Kalman Filter for Luenberger state observer to improve noise suppression performance. The results show that the noise rejection performances of the state augmented Kalman Filters and the time-delayed estimators are much better than the conventional disturbance observers. These two estimators can give not only the estimation of the disturbance but also the low noise level estimations of position and instantaneous velocity. The bandwidth of the state augmented Kalman Filters is wider than the time-delayed estimators. In addition, the state augmented Kalman Filters can give unbiased estimations of the slow varying disturbance and the instantaneous velocity, while the time-delayed estimators can not. The simulation and experiment conducted on X axis of a 2.5-axis prototype micro milling machine are provided.

  15. Calorimeters for Precision Power Dissipation Measurements on Controlled-Temperature Superconducting Radiofrequency Samples

    SciTech Connect

    Xiao, Binping P.; Kelley, Michael J.; Reece, Charles E.; Phillips, H. L.

    2012-12-01

    Two calorimeters, with stainless steel and Cu as the thermal path material for high precision and high power versions, respectively, have been designed and commissioned for the surface impedance characterization (SIC) system at Jefferson Lab to provide low temperature control and measurement for CW power up to 22 W on a 5 cm dia. disk sample which is thermally isolated from the RF portion of the system. A power compensation method has been developed to measure the RF induced power on the sample. Simulation and experimental results show that with these two calorimeters, the whole thermal range of interest for superconducting radiofrequency (SRF) materials has been covered. The power measurement error in the interested power range is within 1.2% and 2.7% for the high precision and high power versions, respectively. Temperature distributions on the sample surface for both versions have been simulated and the accuracy of sample temperature measurements have been analysed. Both versions have the ability to accept bulk superconductors and thin film superconducting samples with a variety of substrate materials such as Al, Al{sub 2}O{sub 3}, Cu, MgO, Nb and Si.

  16. Calorimeters for precision power dissipation measurements on controlled-temperature superconducting radiofrequency samples.

    PubMed

    Xiao, B P; Reece, C E; Phillips, H L; Kelley, M J

    2012-12-01

    Two calorimeters, with stainless steel and Cu as the thermal path material for high precision and high power versions, respectively, have been designed and commissioned for the 7.5 GHz surface impedance characterization system at Jefferson Lab to provide low temperature control and measurement for CW power up to 22 W on a 5 cm diameter disk sample which is thermally isolated from the radiofrequency (RF) portion of the system. A power compensation method has been developed to measure the RF induced power on the sample. Simulation and experimental results show that with these two calorimeters, the whole thermal range of interest for superconducting radiofrequency materials has been covered. The power measurement error in the interested power range is within 1.2% and 2.7% for the high precision and high power versions, respectively. Temperature distributions on the sample surface for both versions have been simulated and the accuracy of sample temperature measurements have been analyzed. Both versions have the ability to accept bulk superconductors and thin film superconducting samples with a variety of substrate materials such as Al, Al(2)O(3), Cu, MgO, Nb, and Si. PMID:23278016

  17. Co on Fe3O4(001): Towards precise control of surface properties.

    PubMed

    Gargallo-Caballero, Raquel; Martín-García, Laura; Quesada, Adrián; Granados-Miralles, Cecilia; Foerster, Michael; Aballe, Lucía; Bliem, Roland; Parkinson, Gareth S; Blaha, Peter; Marco, José F; de la Figuera, Juan

    2016-03-01

    A novel approach to incorporate cobalt atoms into a magnetite single crystal is demonstrated by a combination of x-ray spectro-microscopy, low-energy electron diffraction, and density-functional theory calculations. Co is deposited at room temperature on the reconstructed magnetite (001) surface filling first the subsurface octahedral vacancies and then occupying adatom sites on the surface. Progressive annealing treatments at temperatures up to 733 K diffuse the Co atoms into deeper crystal positions, mainly into octahedral ones with a marked inversion level. The oxidation state, coordination, and magnetic moments of the cobalt atoms are followed from their adsorption to their final incorporation into the bulk, mostly as octahedral Co(2+). This precise control of the near-surface Co atoms location opens up the way to accurately tune the surface physical and magnetic properties of mixed spinel oxides. PMID:26957173

  18. Precision spectroscopy of the molecular ion HD{sup +}: Control of Zeeman shifts

    SciTech Connect

    Bakalov, Dimitar; Korobov, Vladimir; Schiller, Stephan

    2010-11-15

    Precision spectroscopy on cold molecules can potentially enable novel tests of fundamental laws of physics and alternative determination of some fundamental constants. Realizing this potential requires a thorough understanding of the systematic effects that shift the energy levels of molecules. We have performed a complete ab initio calculation of the magnetic field effects for a particular system, the molecular hydrogen ion HD{sup +}. Different spectroscopic schemes have been considered, and several transitions, all accessible by modern radiation sources and exhibiting well controllable or negligible Zeeman shift, have been identified. Thus, HD{sup +} is a candidate for the determination of the ratio of electron-to-nuclear reduced mass, and for tests of its time independence.

  19. Co on Fe3O4(001): Towards precise control of surface properties

    NASA Astrophysics Data System (ADS)

    Gargallo-Caballero, Raquel; Martín-García, Laura; Quesada, Adrián; Granados-Miralles, Cecilia; Foerster, Michael; Aballe, Lucía; Bliem, Roland; Parkinson, Gareth S.; Blaha, Peter; Marco, José F.; de la Figuera, Juan

    2016-03-01

    A novel approach to incorporate cobalt atoms into a magnetite single crystal is demonstrated by a combination of x-ray spectro-microscopy, low-energy electron diffraction, and density-functional theory calculations. Co is deposited at room temperature on the reconstructed magnetite (001) surface filling first the subsurface octahedral vacancies and then occupying adatom sites on the surface. Progressive annealing treatments at temperatures up to 733 K diffuse the Co atoms into deeper crystal positions, mainly into octahedral ones with a marked inversion level. The oxidation state, coordination, and magnetic moments of the cobalt atoms are followed from their adsorption to their final incorporation into the bulk, mostly as octahedral Co2+. This precise control of the near-surface Co atoms location opens up the way to accurately tune the surface physical and magnetic properties of mixed spinel oxides.

  20. Towards precise defect control in layered oxide structures by using oxide molecular beam epitaxy

    PubMed Central

    Baiutti, Federico; Christiani, Georg

    2014-01-01

    Summary In this paper we present the atomic-layer-by-layer oxide molecular beam epitaxy (ALL-oxide MBE) which has been recently installed in the Max-Planck Institute for Solid State Research and we report on its present status, providing some examples that demonstrate its successful application in the synthesis of different layered oxides, with particular reference to superconducting La2CuO4 and insulator-to-metal La2− xSrxNiO4. We briefly review the ALL-oxide MBE technique and its unique capabilities in the deposition of atomically smooth single-crystal thin films of various complex oxides, artificial compounds and heterostructures, introducing our goal of pursuing a deep investigation of such systems with particular emphasis on structural defects, with the aim of tailoring their functional properties by precise defects control. PMID:24995148

  1. Towards precise defect control in layered oxide structures by using oxide molecular beam epitaxy.

    PubMed

    Baiutti, Federico; Christiani, Georg; Logvenov, Gennady

    2014-01-01

    In this paper we present the atomic-layer-by-layer oxide molecular beam epitaxy (ALL-oxide MBE) which has been recently installed in the Max-Planck Institute for Solid State Research and we report on its present status, providing some examples that demonstrate its successful application in the synthesis of different layered oxides, with particular reference to superconducting La2CuO4 and insulator-to-metal La2- x Sr x NiO4. We briefly review the ALL-oxide MBE technique and its unique capabilities in the deposition of atomically smooth single-crystal thin films of various complex oxides, artificial compounds and heterostructures, introducing our goal of pursuing a deep investigation of such systems with particular emphasis on structural defects, with the aim of tailoring their functional properties by precise defects control. PMID:24995148

  2. Controlling the oscillation phase through precisely timed closed-loop optogenetic stimulation: a computational study

    PubMed Central

    Witt, Annette; Palmigiano, Agostina; Neef, Andreas; El Hady, Ahmed; Wolf, Fred; Battaglia, Demian

    2013-01-01

    Dynamic oscillatory coherence is believed to play a central role in flexible communication between brain circuits. To test this communication-through-coherence hypothesis, experimental protocols that allow a reliable control of phase-relations between neuronal populations are needed. In this modeling study, we explore the potential of closed-loop optogenetic stimulation for the control of functional interactions mediated by oscillatory coherence. The theory of non-linear oscillators predicts that the efficacy of local stimulation will depend not only on the stimulation intensity but also on its timing relative to the ongoing oscillation in the target area. Induced phase-shifts are expected to be stronger when the stimulation is applied within specific narrow phase intervals. Conversely, stimulations with the same or even stronger intensity are less effective when timed randomly. Stimulation should thus be properly phased with respect to ongoing oscillations (in order to optimally perturb them) and the timing of the stimulation onset must be determined by a real-time phase analysis of simultaneously recorded local field potentials (LFPs). Here, we introduce an electrophysiologically calibrated model of Channelrhodopsin 2 (ChR2)-induced photocurrents, based on fits holding over two decades of light intensity. Through simulations of a neural population which undergoes coherent gamma oscillations—either spontaneously or as an effect of continuous optogenetic driving—we show that precisely-timed photostimulation pulses can be used to shift the phase of oscillation, even at transduction rates smaller than 25%. We consider then a canonic circuit with two inter-connected neural populations oscillating with gamma frequency in a phase-locked manner. We demonstrate that photostimulation pulses applied locally to a single population can induce, if precisely phased, a lasting reorganization of the phase-locking pattern and hence modify functional interactions between the

  3. Au nanocrystal-directed growth of Au-Cu(2)O core-shell heterostructures with precise morphological control.

    PubMed

    Kuo, Chun-Hong; Hua, Tzu-En; Huang, Michael H

    2009-12-16

    Formation of metal-semiconductor core-shell heterostructures with precise morphological control of both components remains challenging. Heterojunctions, rather than core-shell structures, were typically produced for metal-semiconductor composites. Furthermore, growth of semiconductor shells with systematic shape evolution using the same metal particle cores can also present a significant challenge. Here, we have synthesized Au-Cu(2)O core-shell heterostructures using gold nanoplates, nanorods, octahedra, and highly faceted nanoparticles as the structure-directing cores for the overgrowth of Cu(2)O shells by a facile aqueous solution approach. The gold nanoparticle cores guide the growth of Cu(2)O shells with morphological and orientation control. Systematic shape evolution of the shells can be easily achieved by simply adjusting the volume of reductant added. For example, truncated cubic to octahedral Cu(2)O shells were produced from octahedral gold nanocrystal cores. Unusual truncated stellated icosahedral and star column structures have also been synthesized. The heterostructures were found to be formed via an unusual hollow-shell-refilled growth mechanism not reported before. The approach has potential toward the preparation of other complex Cu(2)O structures with well-defined facets. PMID:19919066

  4. Polymeric Nanoparticles with Precise Ratiometric Control over Drug Loading for Combination Therapy

    PubMed Central

    Aryal, Santosh; Hu, Che-Ming Jack; Zhang, Liangfang

    2011-01-01

    We report a novel approach for nanoparticle-based combination chemotherapy by concurrently incorporating two different types of drugs into a single polymeric nanoparticle with ratiometric control over the loading of the two drugs. By adapting metal alkoxide chemistry, we synthesize highly hydrophobic drug-poly-l-lactide (drug-PLA) conjugates, of which the polymer has the same chain length while the drug may differ. These drug-polymer conjugates are then encapsulated into lipid-coated polymeric nanoparticles through a single-step nanoprecipication method. Using doxorubicin (DOX) and camptothecin (CPT) as two model chemotherapy drugs, various ratios of DOX-PLA and CPT-PLA conjugates are loaded into the nanoparticles with over 90% loading efficiency. The resulting nanoparticles are uniform in size, size distribution and surface charge. The loading yield of DOX and CPT in the particles can be precisely controlled by simply adjusting the DOX-PLA:CPT-PLA molar ratio. Cellular cytotoxicity results show that the dual-drug loaded nanoparticles are superior to the corresponding cocktail mixtures of single-drug loaded nanoparticles. This dual-drug delivery approach offers a solution to the long-standing challenge in ratiometric control over the loading of different types of drugs onto the same drug delivery vehicle. We expect that this approach can be exploited for many types of chemotherapeutic agents containing hydroxyl groups and thus enable co-delivery of various drug combinations for combinatorial treatments of diseases. PMID:21696189

  5. Precision imaging and control for machine vision research at Carnegie Mellon University

    NASA Astrophysics Data System (ADS)

    Willson, Reg G.; Shafer, Steven A.

    1992-08-01

    In a perfect world we would be able to use the many possible degrees of freedom in a camera system to do many useful things such as accommodating for changes or differences in the scenes being imaged correcting for camera behaviour that isn''t quite ideal or measuring properties of the scene by noting how the scene''s image changes as the camera''s parameters are varied. Unfortunately the parameters that control the formation of the camera''s images often interact in complex and subtle ways that can cause unforeseen problems for machine vision tasks. To be able to effectively use multi degree of freedom camera systems we need to know how variations in the camera''s control parameters are going to cause changes in the produced images. For this we need to have good mathematical models describing the relationships between the control parameters and the parameters of the resulting images. Ideally we would like to base the form of the models on an understanding of the underlying physical processes involved but in many cases these are either unknown or are just too complex to model. In these situations experimentation and generalized modeling techniques are necessary. To perform the experiments needed to develop and validate models and to obtain calibration data for the models we need precise automated imaging systems. In this paper we describe the camera systems developed for Carnegie Mellon University''s Calibrated Imaging Lab

  6. Precise and high-speed control of partial pressures of multiple gas species in plasma process chamber using pulse-controlled gas injection

    SciTech Connect

    Morishita, Sadaharu; Goto, Tetsuya; Nagase, Masaaki; Ohmi, Tadahiro

    2009-05-15

    Multiprocesses in a single plasma process chamber with high throughput require precise, sequential, high-speed alteration of partial pressures of multiple gas species. A conventional gas-distribution system cannot realize this because the system seriously overshoots gas pressure immediately following valve operation. Furthermore, chamber volume and conductance of gas piping between the system and chamber should both be considered because they delay the stabilizing time of gas pressure. Therefore, the authors proposed a new gas-distribution system without overshoot by controlling gas flow rate based on pressure measurement, as well as a method of pulse-controlled gas injection immediately following valve operation. Time variation of measured partial pressure agrees well with a calculation based on an equivalent-circuit model that represents the chamber and gas piping between the system and chamber. Using pulse-controlled gas injection, the stabilizing time can be reduced drastically to 0.6 s for HBr added to pure Ar plasma, and 0.7 s for O{sub 2} added to Ar/HBr plasma; without the pulse control, the stabilizing times are 3 and 7 s, respectively. In the O{sub 2} addition case, rapid stabilization can be achieved during the period of line/space pattern etching of poly-Si on a thin SiO{sub 2} film. This occurs without anomalous etching of the underlying SiO{sub 2} film or the Si substrate near the sidewall, thus obtaining a wide process margin with high throughput.

  7. Precision control of lesions by high-intensity focused ultrasound cavitation-based histotripsy through varying pulse duration.

    PubMed

    Xu, Jin; Bigelow, Timothy A; Nagaraju, Ravindra

    2013-07-01

    The goal of this experimental study was to explore the feasibility of acquiring controllable precision through varying pulse duration for lesions generated by cavitation-based histotripsy. Histotripsy uses high-intensity focused ultrasound (HIFU) at low duty factor to create energetic bubble clouds inside tissue to liquefy a region. It uses cavitation-mediated mechanical effects while minimizing heating, and has the advantages of real-time monitoring and lesion fidelity to treatment planning. In our study, histotripsy was applied to three groups of tissue-mimicking agar samples of different stiffnesses (29.4 ± 5.3, 44.8 ± 5.9, and 66.4 ± 7.1 kPa). B-mode imaging was used first to quantify bubble cluster dimensions in both water and agar. Then, a 4.5-mm-wide square (lateral to the focal plane) was scanned in a raster pattern with a step size of 0.75 mm in agar histotripsy experiments to estimate equivalent bubble cluster dimensions based on the histotripsyinduced damage. The 15-s exposure at each treatment location comprised 5000 sine-wave tone bursts at a spatial-peak pulseaverage intensity of 41.1 kW/cm2, with peak compressional and rarefactional pressures of 102 and 17 MPa, respectively. The results showed that bubble cluster width and length increased with pulse duration and decreased with agar stiffness. Therefore, a significant improvement in histotripsy precision could be achieved by reducing the pulse duration. PMID:25004507

  8. Social Axioms and Achievement across Cultures: The Influence of Reward for Application and Fate Control

    ERIC Educational Resources Information Center

    Zhou, Fan; Leung, Kwok; Bond, Michael Harris

    2009-01-01

    The present research examined the relationships between two social axiom dimensions, reward for application and fate control, with various achievement-related indexes across a wide range of cultures. Results showed that there was no relationship between reward for application and academic achievement or economic competitiveness, but reward for…

  9. A Model of Parental Achievement-Oriented Psychological Control in Academically Gifted Students

    ERIC Educational Resources Information Center

    Garn, Alex C.; Jolly, Jennifer L.

    2015-01-01

    This study investigated achievement-oriented parent socialization as it pertains to school avoidance in a sample of gifted students. A serial mediation model examining relationships among parental achievement-oriented psychological control (APC), fear of academic failure, academic amotivation, and school avoidance was tested. The sample included…

  10. Parental Warmth, Control, and Involvement in Schooling: Predicting Academic Achievement among Korean American Adolescents.

    ERIC Educational Resources Information Center

    Kim, Kyoungho; Rohner, Ronald P.

    2002-01-01

    Explored the relationship between parenting style and academic achievement of Korean American adolescents, investigating the influence of perceived parental warmth and control and improvement in schooling. Survey data indicated that authoritative paternal parenting related to optimal academic achievement. Differences in maternal parenting styles…

  11. Interactions between Student Achievement, Locus of Control, and Two Methods of College Instruction.

    ERIC Educational Resources Information Center

    Root, Jon R.; Gall, Meredith Damien

    1981-01-01

    Fifty-nine undergraduate students, divided into two groups to compare the instructional motivational effects of auto-tutorial and conventional instruction, were tested for achievement via performance (Ac), achievement via independence (Ai), and internal-external locus of control. Significant interaction was found between Ac and the two methods of…

  12. Children's Self-Regulation and School Achievement in Cultural Contexts: The Role of Maternal Restrictive Control.

    PubMed

    Weis, Mirjam; Trommsdorff, Gisela; Muñoz, Lorena

    2016-01-01

    Self-regulation can be developed through parent-child interactions and has been related to developmental outcomes, e.g., such as educational achievement. This study examined cross-cultural differences and similarities in maternal restrictive control, self-regulation (i.e., behavior and emotion regulation) and school achievement and relations among these variables in Germany and Chile. Seventy-six German and 167 Chilean fourth graders, their mothers, and their teachers participated. Mothers and teachers rated children's behavior regulation with a subscale of the Strengths and Difficulties Questionnaire. Children reported their use of emotion regulation strategies on the Questionnaire for the Measurement of Stress and Coping. Mothers rated maternal restrictive control by answering the Parenting Practice Questionnaire. School achievement was assessed by grades for language and mathematics. Results showed higher behavior regulation of German children in comparison to Chilean children and a higher preference of restrictive parental control in Chilean mothers than in German mothers. Regression analyses revealed positive relations between children's behavior regulation and school achievement in Germany and in Chile. Further, in both cultural contexts, maternal restrictive control was related negatively to behavior regulation and positively to anger-oriented emotion regulation. In sum, the study showed the central function of behavior regulation for school achievement underlining negative relations of maternal restrictive control with children's self-regulation and school achievement in diverse cultural contexts. Culturally adapted interventions related to parenting practices to promote children's behavior regulation may assist in also promoting children's school achievement. PMID:27303318

  13. Children's Self-Regulation and School Achievement in Cultural Contexts: The Role of Maternal Restrictive Control

    PubMed Central

    Weis, Mirjam; Trommsdorff, Gisela; Muñoz, Lorena

    2016-01-01

    Self-regulation can be developed through parent-child interactions and has been related to developmental outcomes, e.g., such as educational achievement. This study examined cross-cultural differences and similarities in maternal restrictive control, self-regulation (i.e., behavior and emotion regulation) and school achievement and relations among these variables in Germany and Chile. Seventy-six German and 167 Chilean fourth graders, their mothers, and their teachers participated. Mothers and teachers rated children's behavior regulation with a subscale of the Strengths and Difficulties Questionnaire. Children reported their use of emotion regulation strategies on the Questionnaire for the Measurement of Stress and Coping. Mothers rated maternal restrictive control by answering the Parenting Practice Questionnaire. School achievement was assessed by grades for language and mathematics. Results showed higher behavior regulation of German children in comparison to Chilean children and a higher preference of restrictive parental control in Chilean mothers than in German mothers. Regression analyses revealed positive relations between children's behavior regulation and school achievement in Germany and in Chile. Further, in both cultural contexts, maternal restrictive control was related negatively to behavior regulation and positively to anger-oriented emotion regulation. In sum, the study showed the central function of behavior regulation for school achievement underlining negative relations of maternal restrictive control with children's self-regulation and school achievement in diverse cultural contexts. Culturally adapted interventions related to parenting practices to promote children's behavior regulation may assist in also promoting children's school achievement. PMID:27303318

  14. Precision powder feeder

    DOEpatents

    Schlienger, M. Eric; Schmale, David T.; Oliver, Michael S.

    2001-07-10

    A new class of precision powder feeders is disclosed. These feeders provide a precision flow of a wide range of powdered materials, while remaining robust against jamming or damage. These feeders can be precisely controlled by feedback mechanisms.

  15. Predicted Performance of On-Off Systems for Precise Satellite Attitude Control

    NASA Technical Reports Server (NTRS)

    Brown, Stuart C.

    1961-01-01

    An investigation has been made of the use of on-off reaction jets for precision attitude control of a satellite. Since a symmetrical vehicle is assumed, only single-axis control needs to be considered. The responses to initial disturbances and also limit-cycle characteristics for several systems have been evaluated. Calculated results indicate that realistic values of settling time and fuel consumption for the example considered can be obtained. The performance of a given system depends on the characteristics of the error detector used. In cases where the detector output was saturated for a relatively low error input, the settling time deteriorated when a lead network was used to provide damping. This deterioration could be eliminated if a separate rate signal to produce vehicle rate limiting were available. As an alternate approach, two systems were investigated which used a timed sequence of torques and could operate with a detector output of very small linear range. Although the performance of these systems was poorer than that of the lead network system without detector saturation, the performance was better than that of the lead network system with low values of detector saturation. The effects on limit-cycle characteristics of hysteresis, lead network constants, dead zone, and thrust time delays were also investigated.

  16. Precision control of thermal transport in cryogenic single-crystal silicon devices

    NASA Astrophysics Data System (ADS)

    Rostem, K.; Chuss, D. T.; Colazo, F. A.; Crowe, E. J.; Denis, K. L.; Lourie, N. P.; Moseley, S. H.; Stevenson, T. R.; Wollack, E. J.

    2014-03-01

    We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path ℓ is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than ℓ, even when the surface is fairly smooth, 5-10 nm rms, and the peak thermal wavelength is 0.6 μm. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order ℓ, the conductance is dominated by ballistic transport and is effectively set by the beam cross-sectional area. We have demonstrated a uniformity of ±8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors.

  17. Synthetic biosensors for precise gene control and real-time monitoring of metabolites

    PubMed Central

    Rogers, Jameson K.; Guzman, Christopher D.; Taylor, Noah D.; Raman, Srivatsan; Anderson, Kelley; Church, George M.

    2015-01-01

    Characterization and standardization of inducible transcriptional regulators has transformed how scientists approach biology by allowing precise and tunable control of gene expression. Despite their utility, only a handful of well-characterized regulators exist, limiting the complexity of engineered biological systems. We apply a characterization pipeline to four genetically encoded sensors that respond to acrylate, glucarate, erythromycin and naringenin. We evaluate how the concentration of the inducing chemical relates to protein expression, how the extent of induction affects protein expression kinetics, and how the activation behavior of single cells relates to ensemble measurements. We show that activation of each sensor is orthogonal to the other sensors, and to other common inducible systems. We demonstrate independent control of three fluorescent proteins in a single cell, chemically defining eight unique transcriptional states. To demonstrate biosensor utility in metabolic engineering, we apply the glucarate biosensor to monitor product formation in a heterologous glucarate biosynthesis pathway and identify superior enzyme variants. Doubling the number of well-characterized inducible systems makes more complex synthetic biological circuits accessible. Characterizing sensors that transduce the intracellular concentration of valuable metabolites into fluorescent readouts enables high-throughput screening of biological catalysts and alleviates the primary bottleneck of the metabolic engineering design-build-test cycle. PMID:26152303

  18. A study of attitude control concepts for precision-pointing non-rigid spacecraft

    NASA Technical Reports Server (NTRS)

    Likins, P. W.

    1975-01-01

    Attitude control concepts for use onboard structurally nonrigid spacecraft that must be pointed with great precision are examined. The task of determining the eigenproperties of a system of linear time-invariant equations (in terms of hybrid coordinates) representing the attitude motion of a flexible spacecraft is discussed. Literal characteristics are developed for the associated eigenvalues and eigenvectors of the system. A method is presented for determining the poles and zeros of the transfer function describing the attitude dynamics of a flexible spacecraft characterized by hybrid coordinate equations. Alterations are made to linear regulator and observer theory to accommodate modeling errors. The results show that a model error vector, which evolves from an error system, can be added to a reduced system model, estimated by an observer, and used by the control law to render the system less sensitive to uncertain magnitudes and phase relations of truncated modes and external disturbance effects. A hybrid coordinate formulation using the provided assumed mode shapes, rather than incorporating the usual finite element approach is provided.

  19. Precise spatial control of cavitation erosion in a vessel phantom by using an ultrasonic standing wave.

    PubMed

    Shi, Aiwei; Huang, Peixuan; Guo, Shifang; Zhao, Lu; Jia, Yingjie; Zong, Yujin; Wan, Mingxi

    2016-07-01

    In atherosclerotic inducement in animal models, the conventionally used balloon injury is invasive, produces excessive vessel injuries at unpredictable locations and is inconvenient in arterioles. Fortunately, cavitation erosion, which plays an important role in therapeutic ultrasound in blood vessels, has the potential to induce atherosclerosis noninvasively at predictable sites. In this study, precise spatial control of cavitation erosion for superficial lesions in a vessel phantom was realised by using an ultrasonic standing wave (USW) with the participation of cavitation nuclei and medium-intensity ultrasound pulses. The superficial vessel erosions were restricted between adjacent pressure nodes, which were 0.87 mm apart in the USW field of 1 MHz. The erosion positions could be shifted along the vessel by nodal modulation under a submillimetre-scale accuracy without moving the ultrasound transducers. Moreover, the cavitation erosion of the proximal or distal wall could be determined by the types of cavitation nuclei and their corresponding cavitation pulses, i.e., phase-change microbubbles with cavitation pulses of 5 MHz and SonoVue microbubbles with cavitation pulses of 1 MHz. Effects of acoustic parameters of the cavitation pulses on the cavitation erosions were investigated. The flow conditions in the experiments were considered and discussed. Compared to only using travelling waves, the proposed method in this paper improves the controllability of the cavitation erosion and reduces the erosion depth, providing a more suitable approach for vessel endothelial injury while avoiding haemorrhage. PMID:26964937

  20. Precision control of thermal transport in cryogenic single-crystal silicon devices

    SciTech Connect

    Rostem, K.; Chuss, D. T.; Colazo, F. A.; Crowe, E. J.; Denis, K. L.; Lourie, N. P.; Moseley, S. H.; Stevenson, T. R.; Wollack, E. J.

    2014-03-28

    We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path ℓ is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than ℓ, even when the surface is fairly smooth, 5–10 nm rms, and the peak thermal wavelength is 0.6 μm. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order ℓ, the conductance is dominated by ballistic transport and is effectively set by the beam cross-sectional area. We have demonstrated a uniformity of ±8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors.

  1. Melting and Discharge Phenomena of Breaking Ag Contacts Using a Precisely Controlled Piezoelectric Actuator

    NASA Astrophysics Data System (ADS)

    Kudo, Takayuki; Wakatsuki, Noboru

    2010-07-01

    Using a laminated ceramic piezoelectric actuator for a very slow (4.5 µm/s) precisely controlled make/break operation, the contact voltage Vc, the contact current Ic, and the amounts of residue of the melt and discharged surface and discharge for breaking hinge relays with Ag-contacting electrodes were measured. To control mechanical conditions, we used a movable electrode with a finely shaped convex surface (radius of curvature: 0.5 mm) and a flat fixed electrode. Every make/break operation causes surface irregularity. Therefore, the operation was performed only once. In order to measure the area of the contacted surface after metal melting and arc ignition, Vc and Ic was adjusted to be 25 V and 1.2 A, respectively. Even when Vc and Ic were larger than the minimum arc voltage and minimum arc current, respectively, electric discharge was spontaneously suppressed below 130 µs. The residues of discharge were multiple scars with radii in the range of 100 µm, which had a black and/or white rectangular convex or concave shape.

  2. Melting and Discharge Phenomena of Breaking Ag Contacts Using a Precisely Controlled Piezoelectric Actuator

    NASA Astrophysics Data System (ADS)

    Takayuki Kudo,; Noboru Wakatsuki,

    2010-07-01

    Using a laminated ceramic piezoelectric actuator for a very slow (4.5 μm/s) precisely controlled make/break operation, the contact voltage Vc, the contact current Ic, and the amounts of residue of the melt and discharged surface and discharge for breaking hinge relays with Ag-contacting electrodes were measured. To control mechanical conditions, we used a movable electrode with a finely shaped convex surface (radius of curvature: 0.5 mm) and a flat fixed electrode. Every make/break operation causes surface irregularity. Therefore, the operation was performed only once. In order to measure the area of the contacted surface after metal melting and arc ignition, Vc and Ic was adjusted to be 25 V and 1.2 A, respectively. Even when Vc and Ic were larger than the minimum arc voltage and minimum arc current, respectively, electric discharge was spontaneously suppressed below 130 μs. The residues of discharge were multiple scars with radii in the range of 100 μm, which had a black and/or white rectangular convex or concave shape.

  3. Evaluation of SMART sensor displays for multidimensional precision control of Space Shuttle remote manipulator

    NASA Technical Reports Server (NTRS)

    Bejczy, A. K.; Brown, J. W.; Lewis, J. L.

    1982-01-01

    An enhanced proximity sensor and display system was developed at the Jet Propulsion Laboratory (JPL) and tested on the full scale Space Shuttle Remote Manipulator at the Johnson Space Center (JSC) Manipulator Development Facility (MDF). The sensor system, integrated with a four-claw end effector, measures range error up to 6 inches, and pitch and yaw alignment errors within + or 15 deg., and displays error data on both graphic and numeric displays. The errors are referenced to the end effector control axes through appropriate data processing by a dedicated microcomputer acting on the sensor data in real time. Both display boxes contain a green lamp which indicates whether the combination of range, pitch and yaw errors will assure a successful grapple. More than 200 test runs were completed in early 1980 by three operators at JSC for grasping static and capturing slowly moving targets. The tests have indicated that the use of graphic/numeric displays of proximity sensor information improves precision control of grasp/capture range by more than a factor of two for both static and dynamic grapple conditions.

  4. A versatile synthesis method of dendrites-free segmented nanowires with a precise size control

    PubMed Central

    2012-01-01

    We report an innovative strategy to obtain cylindrical nanowires combining well established and low-cost bottom-up methods such as template-assisted nanowires synthesis and electrodeposition process. This approach allows the growth of single-layer or multi-segmented nanowires with precise control over their length (from few nanometers to several micrometers). The employed techniques give rise to branched pores at the bottom of the templates and consequently dendrites at the end of the nanowires. With our method, these undesired features are easily removed from the nanowires by a selective chemical etching. This is crucial for magnetic characterizations where such non-homogeneous branches may introduce undesired features into the final magnetic response. The obtained structures show extremely narrow distributions in diameter and length, improved robustness and high-yield, making this versatile approach strongly compatible with large scale production at an industrial level. Finally, we show the possibility to tune accurately the size of the nanostructures and consequently provide an easy control over the magnetic properties of these nanostructures. PMID:22390637

  5. Precision Control of Thermal Transport in Cryogenic Single-Crystal Silicon Devices

    NASA Technical Reports Server (NTRS)

    Rostem, K.; Chuss, D. T.; Colazo, F. A.; Crowe, E. J.; Denis, K. L.; Lourie, N. P.; Moseley, S. H.; Stevenson, T. R.; Wollack, E. J.

    2014-01-01

    We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than, even when the surface is fairly smooth, 510 nm rms, and the peak thermal wavelength is 0.6 microns. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order, the conductance is dominated by ballistic transport and is effectively set by the beam cross-sectional area. We have demonstrated a uniformity of +/-8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors.

  6. Micro-precision control/structure interaction technology for large optical space systems

    NASA Technical Reports Server (NTRS)

    Sirlin, Samuel W.; Laskin, Robert A.

    1993-01-01

    The CSI program at JPL is chartered to develop the structures and control technology needed for sub-micron level stabilization of future optical space systems. The extreme dimensional stability required for such systems derives from the need to maintain the alignment and figure of critical optical elements to a small fraction (typically 1/20th to 1/50th) of the wavelength of detected radiation. The wavelength is about 0.5 micron for visible light and 0.1 micron for ultra-violet light. This lambda/50 requirement is common to a broad class of optical systems including filled aperture telescopes (with monolithic or segmented primary mirrors), sparse aperture telescopes, and optical interferometers. The challenge for CSI arises when such systems become large, with spatially distributed optical elements mounted on a lightweight, flexible structure. In order to better understand the requirements for micro-precision CSI technology, a representative future optical system was identified and developed as an analytical testbed for CSI concepts and approaches. An optical interferometer was selected as a stressing example of the relevant mission class. The system that emerged was termed the Focus Mission Interferometer (FMI). This paper will describe the multi-layer control architecture used to address the FMI's nanometer level stabilization requirements. In addition the paper will discuss on-going and planned experimental work aimed at demonstrating that multi-layer CSI can work in practice in the relevant performance regime.

  7. System identification for precision control of a wingsailed GPS-guided catamaran

    NASA Astrophysics Data System (ADS)

    Elkaim, Gabriel Hugh

    This thesis details the Atlantis project, whose aim is the design, development, and experimental testing of an autonomous wind-propelled marine craft. Functionally, such a vehicle is the marine equivalent of an unmanned aerial vehicle (UAV), and would serve similar purposes. The Atlantis project has been able to demonstrate an advance in control precision of a wind-propelled marine vehicle from typical commercial autopilot accuracy of 100 meters to an accuracy of better than one meter with a prototype based on a modified Prindle-19 light catamaran. The project involves substantial innovations in three areas: wind-propulsion system, overall system architecture, and sensors. The wind-propulsion system is a rigid wing-sail mounted vertically on bearings, mass balanced to allow free rotation in azimuth about a stub-mast. Aerodynamic torque about the stub-mast is trimmed using a flying tail mounted on booms aft of the wing. This arrangement allows the wing-sail to automatically attain the optimum angle to the wind, and weathervane into gusts without inducing large heeling moments. The sensor system uses differential Global Positioning System (DGPS) augmented by a low-cost attitude system based on accelerometer- and magnetometer-triads for position and velocity measurements. Accurate attitude determination is required to create a synthetic position sensor that is located at the center-of-gravity (c.g.) of the boat, rather than at the Global Positioning System (GPS) antenna location. A high-performance estimator/controller was implemented and tested on the full-scale prototype. The identified controllers were able to perform remarkably well, in the presence of wind and waves, tracking the desired line to within 0.3 meters (˜1 foot).

  8. Control of Precision Grip Force in Lifting and Holding of Low-Mass Objects.

    PubMed

    Hiramatsu, Yuichi; Kimura, Daisuke; Kadota, Koji; Ito, Taro; Kinoshita, Hiroshi

    2015-01-01

    Few studies have investigated the control of grip force when manipulating an object with an extremely small mass using a precision grip, although some related information has been provided by studies conducted in an unusual microgravity environment. Grip-load force coordination was examined while healthy adults (N = 17) held a moveable instrumented apparatus with its mass changed between 6 g and 200 g in 14 steps, with its grip surface set as either sandpaper or rayon. Additional measurements of grip-force-dependent finger-surface contact area and finger skin indentation, as well as a test of weight discrimination, were also performed. For each surface condition, the static grip force was modulated in parallel with load force while holding the object of a mass above 30 g. For objects with mass smaller than 30 g, on the other hand, the parallel relationship was changed, resulting in a progressive increase in grip-to-load force (GF/LF) ratio. The rayon had a higher GF/LF force ratio across all mass levels. The proportion of safety margin in the static grip force and normalized moment-to-moment variability of the static grip force were also elevated towards the lower end of the object mass for both surfaces. These findings indicate that the strategy of grip force control for holding objects with an extremely small mass differs from that with a mass above 30 g. The data for the contact area, skin indentation, and weight discrimination suggest that a decreased level of cutaneous feedback signals from the finger pads could have played some role in a cost function in efficient grip force control with low-mass objects. The elevated grip force variability associated with signal-dependent and internal noises, and anticipated inertial force on the held object due to acceleration of the arm and hand, could also have contributed to the cost function. PMID:26376484

  9. Control of Precision Grip Force in Lifting and Holding of Low-Mass Objects

    PubMed Central

    Kimura, Daisuke; Kadota, Koji; Ito, Taro

    2015-01-01

    Few studies have investigated the control of grip force when manipulating an object with an extremely small mass using a precision grip, although some related information has been provided by studies conducted in an unusual microgravity environment. Grip-load force coordination was examined while healthy adults (N = 17) held a moveable instrumented apparatus with its mass changed between 6 g and 200 g in 14 steps, with its grip surface set as either sandpaper or rayon. Additional measurements of grip-force-dependent finger-surface contact area and finger skin indentation, as well as a test of weight discrimination, were also performed. For each surface condition, the static grip force was modulated in parallel with load force while holding the object of a mass above 30 g. For objects with mass smaller than 30 g, on the other hand, the parallel relationship was changed, resulting in a progressive increase in grip-to-load force (GF/LF) ratio. The rayon had a higher GF/LF force ratio across all mass levels. The proportion of safety margin in the static grip force and normalized moment-to-moment variability of the static grip force were also elevated towards the lower end of the object mass for both surfaces. These findings indicate that the strategy of grip force control for holding objects with an extremely small mass differs from that with a mass above 30 g. The data for the contact area, skin indentation, and weight discrimination suggest that a decreased level of cutaneous feedback signals from the finger pads could have played some role in a cost function in efficient grip force control with low-mass objects. The elevated grip force variability associated with signal-dependent and internal noises, and anticipated inertial force on the held object due to acceleration of the arm and hand, could also have contributed to the cost function. PMID:26376484

  10. Improved PHIP polarization using a precision, low noise, voltage controlled current source

    NASA Astrophysics Data System (ADS)

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files.

  11. AMF phasing—A precise control of the ignition timing of AKM for reduction of the injection error

    NASA Astrophysics Data System (ADS)

    Homma, Masanori; Utajima, Masayoshi; Okamoto, Toshio; Hiraishi, Kenji; Takezawa, Susumu

    This paper deals with a new concept, named "AMF Phasing", which intends to minimize the effect of injection error that would result during apogee motor firing (AMF) of the spinning spacecraft. The characteristic of velocity increment error is derived analytically, based on the disturbed spinning motion during AMF. In order to precisely estimate the amount of fuel required for post-AMF orbital correction maneuvers, a probability model is proposed which estimates the total injection error probability combining the dominant error factors, i.e. pre-AMF attitude determination error and velocity increment error during AMF. It is shown that a substantial saving in fuel normally consumed for post-AMF can be expected, when the resultant velocity increment error contribution, which otherwise would be randomly directed in inertial space, is controlled so that it appears in the direction of local right ascension by igniting AKM at the proper instant (AMF Phasing). The procedure for AMF phasing, using a Sun pulse as a reference signal for the ignition timing is described in this paper. It was actually applied for GMS-2, Japan's second Geostationary Meteorological Satellite (HIMAWARI-II). The HIMAWARI-II post-AMF orbit determination shows that AMF Phasing worked successfully and it is concluded that a substantial fuel saving was achieved.

  12. Development and modulation of intrinsic membrane properties control the temporal precision of auditory brain stem neurons.

    PubMed

    Franzen, Delwen L; Gleiss, Sarah A; Berger, Christina; Kümpfbeck, Franziska S; Ammer, Julian J; Felmy, Felix

    2015-01-15

    Passive and active membrane properties determine the voltage responses of neurons. Within the auditory brain stem, refinements in these intrinsic properties during late postnatal development usually generate short integration times and precise action-potential generation. This developmentally acquired temporal precision is crucial for auditory signal processing. How the interactions of these intrinsic properties develop in concert to enable auditory neurons to transfer information with high temporal precision has not yet been elucidated in detail. Here, we show how the developmental interaction of intrinsic membrane parameters generates high firing precision. We performed in vitro recordings from neurons of postnatal days 9-28 in the ventral nucleus of the lateral lemniscus of Mongolian gerbils, an auditory brain stem structure that converts excitatory to inhibitory information with high temporal precision. During this developmental period, the input resistance and capacitance decrease, and action potentials acquire faster kinetics and enhanced precision. Depending on the stimulation time course, the input resistance and capacitance contribute differentially to action-potential thresholds. The decrease in input resistance, however, is sufficient to explain the enhanced action-potential precision. Alterations in passive membrane properties also interact with a developmental change in potassium currents to generate the emergence of the mature firing pattern, characteristic of coincidence-detector neurons. Cholinergic receptor-mediated depolarizations further modulate this intrinsic excitability profile by eliciting changes in the threshold and firing pattern, irrespective of the developmental stage. Thus our findings reveal how intrinsic membrane properties interact developmentally to promote temporally precise information processing. PMID:25355963

  13. Goal Orientations, Locus of Control and Academic Achievement in Prospective Teachers: An Individual Differences Perspective

    ERIC Educational Resources Information Center

    Bulus, Mustafa

    2011-01-01

    The aim of this study is to investigate the role of the prospective teachers' locus of control in goal orientations and of both orientations in academic achievement. The participants were 270 undergraduate students studying in different majors at the Faculty of Education in Pamukkale University. Goal Orientations and Locus of Control Scales were…

  14. On the Relation of Locus of Control and L2 Reading and Writing Achievement

    ERIC Educational Resources Information Center

    Ghonsooly, Behzad; Shirvan, Majid Elahi

    2011-01-01

    Locus of control, a psychological construct, has been the focus of attention in recent decades. Psychologists have discussed the effect of locus of control on achieving life goals in social/psychological interactions. While learning a foreign language involves both social interactions and psychological processes, the role and relation of locus of…

  15. Precise control of critical dimension shrinkage and enlargement by in-situ polysilicon etch

    NASA Astrophysics Data System (ADS)

    Linliu, Kung; Kuo, Mai-Rue

    2000-07-01

    The control of critical dimension shrinkage and enlargement of polysilicon line or space obtained precisely using in- situ process with different ratio of gas combination is investigate din this paper. A polysilicon line could be etched down to 0.054 micrometers from 0.22 micrometers of the original critical dimension (CD). The CD shrinking rate of polysilicon line is 2.48 nm per second per side. On the other hand, the space can also be trimmed down to 0.03 micrometers from the original CD of 0.3 micrometers . The CD enlarging rate of polysilicon rate is 0.421 nm per second per side using the present polymer deposition method. The factors that cause shrinkage and enlargement of CD are the etching of photoresist and the deposition of polymer on the surface of photoresist, respectively. The oxygen-rich gas is used for the shrinkage of CD and the fluorocarbon-rich gas is used for the enlargement of CD. Therefore, a critical dimension could not afforded by the present existed optical photolithography tool or method might probably be solved by alternative innovation such as the plasma dry etching technology.

  16. Caloric restriction and the precision-control of autophagy: A strategy for delaying neurodegenerative disease progression.

    PubMed

    Ntsapi, C; Loos, B

    2016-10-01

    Caloric restriction (CR) is known to extend lifespan in most organisms, indicating that nutrient and energy regulatory mechanisms impact aging. The greatest risk factor for neurodegeneration is age; thus, the antiaging effects of CR might attenuate progressive cell death and avert the aggregation of abnormal proteins associated with neurodegenerative diseases. CR is a potent inducer of autophagy, a tightly regulated intracellular process that facilitates recycling of abnormal protein aggregates and damaged organelles into bioenergetic and biosynthetic materials to maintain homeostasis. Thus, dysregulated autophagy can lead to cellular dysfunction, abnormal protein accumulation, proteotoxicity and subsequently the onset of several neurodegenerative diseases. Therefore, the targeted and precision-controlled activation of autophagy represents a promising therapeutic strategy. Non-pharmacological therapeutic interventions that delay aging by modulating specific stages of autophagy might be beneficial against premature aging, neurodegeneration and its associated ailments. However, the dynamic and often compensatory cross-talk that exists between the protein degradation pathways makes clinical translational approaches challenging. Here we review the primary autophagy pathways in the context of age-related neurodegenerative diseases, focusing on compensatory mechanisms and pathway failure. By critically assessing each underlying molecular machinery, we reveal their impact on aging and unmask the role of caloric restriction in changing cellular fate by delayed aging through stimulation of autophagy. This may point towards novel and better targeted interventions that exploit the autophagic machinery in the treatment of neurodegenerative diseases. PMID:27473756

  17. Negative Feedback Loops Involving Small Regulatory RNAs Precisely Control the Vibrio harveyi Quorum-Sensing Response

    PubMed Central

    Tu, Kimberly C.; Long, Tao; Svenningsen, Sine L.; Wingreen, Ned S.; Bassler, Bonnie L.

    2010-01-01

    Summary Quorum sensing (QS) bacteria assess population density through secretion and detection of molecules called autoinducers (AIs). We identify and characterize two Vibrio harveyi negative feedback loops that facilitate precise transitions between low-cell-density (LCD) and high-cell-density (HCD) states. The QS central regulator LuxO autorepresses its own transcription and the Qrr small regulatory RNAs (sRNAs) posttranscriptionally repress luxO. Disrupting feedback increases the concentration of AIs required for cells to transit from LCD to HCD QS modes. Thus, the two cooperative negative feedback loops determine the point at which V. harveyi has reached a quorum and control the range of AIs over which the transition occurs. Negative feedback regulation also constrains the range of QS output – by preventing sRNA levels from becoming too high and preventing luxO mRNA levels from reaching zero. We suggest that sRNA-mediated feedback regulation is a network design feature that permits fine-tuning of gene regulation and maintenance of homeostasis. PMID:20188674

  18. A biomimetic hybrid nanoplatform for encapsulation and precisely controlled delivery of therasnostic agents

    PubMed Central

    Wang, Hai; Agarwal, Pranay; Zhao, Shuting; Yu, Jianhua; Lu, Xiongbin; He, Xiaoming

    2015-01-01

    Nanoparticles have demonstrated great potential for enhancing drug delivery. However, the low drug encapsulation efficiency at high drug-to-nanoparticle feeding ratios and minimal drug loading content in nanoparticle at any feeding ratios are major hurdles to their widespread applications. Here we report a robust eukaryotic cell-like hybrid nanoplatform (EukaCell) for encapsulation of theranostic agents (doxorubicin and indocyanine green). The EukaCell consists of a phospholipid membrane, a cytoskeleton-like mesoporous silica matrix and a nucleus-like fullerene core. At high drug-to-nanoparticle feeding ratios (for example, 1:0.5), the encapsulation efficiency and loading content can be improved by 58 and 21 times, respectively, compared with conventional silica nanoparticles. Moreover, release of the encapsulated drug can be precisely controlled via dosing near infrared laser irradiation. Ultimately, the ultra-high (up to ∼87%) loading content renders augmented anticancer capacity both in vitro and in vivo. Our EukaCell is valuable for drug delivery to fight against cancer and potentially other diseases. PMID:26621191

  19. Controlled Living Nanowire Growth: Precise Control over the Morphology and Optical Properties of AgAuAg Bimetallic Nanowires.

    PubMed

    Mayer, Martin; Scarabelli, Leonardo; March, Katia; Altantzis, Thomas; Tebbe, Moritz; Kociak, Mathieu; Bals, Sara; García de Abajo, F Javier; Fery, Andreas; Liz-Marzán, Luis M

    2015-08-12

    Inspired by the concept of living polymerization reaction, we are able to produce silver-gold-silver nanowires with a precise control over their total length and plasmonic properties by establishing a constant silver deposition rate on the tips of penta-twinned gold nanorods used as seed cores. Consequently, the length of the wires increases linearly in time. Starting with ∼210 nm × 32 nm gold cores, we produce nanowire lengths up to several microns in a highly controlled manner, with a small self-limited increase in thickness of ∼4 nm, corresponding to aspect ratios above 100, whereas the low polydispersity of the product allows us to detect up to nine distinguishable plasmonic resonances in a single colloidal solution. We analyze the spatial distribution and the nature of the plasmons by electron energy loss spectroscopy and obtain excellent agreement between measurements and electromagnetic simulations, clearly demonstrating that the presence of the gold core plays a marginal role, except for relatively short wires or high-energy modes. PMID:26134470

  20. Controlled Living Nanowire Growth: Precise Control over the Morphology and Optical Properties of AgAuAg Bimetallic Nanowires

    PubMed Central

    2015-01-01

    Inspired by the concept of living polymerization reaction, we are able to produce silver–gold–silver nanowires with a precise control over their total length and plasmonic properties by establishing a constant silver deposition rate on the tips of penta-twinned gold nanorods used as seed cores. Consequently, the length of the wires increases linearly in time. Starting with ∼210 nm × 32 nm gold cores, we produce nanowire lengths up to several microns in a highly controlled manner, with a small self-limited increase in thickness of ∼4 nm, corresponding to aspect ratios above 100, whereas the low polydispersity of the product allows us to detect up to nine distinguishable plasmonic resonances in a single colloidal solution. We analyze the spatial distribution and the nature of the plasmons by electron energy loss spectroscopy and obtain excellent agreement between measurements and electromagnetic simulations, clearly demonstrating that the presence of the gold core plays a marginal role, except for relatively short wires or high-energy modes. PMID:26134470

  1. How do different components of Effortful Control contribute to children's mathematics achievement?

    PubMed

    Sánchez-Pérez, Noelia; Fuentes, Luis J; Pina, Violeta; López-López, Jose A; González-Salinas, Carmen

    2015-01-01

    This work sought to investigate the specific contribution of two different components of Effortful Control (EC) -attentional focusing (AF) and inhibitory control- to children's mathematics achievement. The sample was composed of 142 children aged 9-12 year-old. EC components were measured through the Temperament in Middle Childhood Questionnaire (TMCQ; parent's report); math achievement was measured via teacher's report and through the standard Woodcock-Johnson test. Additionally, the contribution of other cognitive and socio-emotional processes was taken into account. Our results showed that only AF significantly contributed to the variance of children's mathematics achievement; interestingly, mediational models showed that the relationship between effortful attentional self-regulation and mathematics achievement was mediated by academic peer popularity, as well as by intelligence and study skills. Results are discussed in the light of the current theories on the role of children's self-regulation abilities in the context of school. PMID:26441758

  2. Locus of control, test anxiety, academic procrastination, and achievement among college students.

    PubMed

    Carden, Randy; Bryant, Courtney; Moss, Rebekah

    2004-10-01

    114 undergraduates completed the Internal-External Locus of Control scale, the Procrastination Scale, and the Achievement Anxiety Test. They also provided a self-report of their cumulative GPA. Students were divided into two groups by a median-split of 10.5, yielding an internally oriented group of 57 and an externally oriented group of 57. The former students showed significantly lower academic procrastination, debilitating test anxiety, and reported higher academic achievement than the latter. PMID:15587223

  3. Acceleration feedback control (AFC) enhanced by disturbance observation and compensation (DOC) for high precision tracking in telescope systems

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Cai, Hua-Xiang; Huang, Yong-Mei; Ge, Liang; Tang, Tao; Su, Yan-Rui; Liu, Xiang; Li, Jin-Ying; He, Dong; Du, Sheng-Ping; Ling, Yu

    2016-08-01

    In this paper, a cascade acceleration feedback control (AFC) enhanced by a disturbance observation and compensation (DOC) method is proposed to improve the tracking precision of telescope systems. Telescope systems usually suffer some uncertain disturbances, such as wind load, nonlinear friction and other unknown disturbances. To ensure tracking precision, an acceleration feedback loop which can increase the stiffness of such a system is introduced. Moreover, to further improve the tracking precision, we introduce the DOC method which can accurately estimate the disturbance and compensate it. Furthermore, the analysis of tracking accuracy used by this method is proposed. Finally, a few comparative experimental results show that the proposed control method has excellent performance for reducing the tracking error of a telescope system.

  4. Precise control of polymer coated nanopores by nanoparticle additives: Insights from computational modeling

    NASA Astrophysics Data System (ADS)

    Eskandari Nasrabad, Afshin; Jasnow, David; Zilman, Anton; Coalson, Rob D.

    2016-08-01

    Polymer-nanoparticle composites are a promising new class of materials for creation of controllable nano-patterned surfaces and nanopores. We use coarse-grained molecular dynamics simulations augmented with analytical theory to study the structural transitions of surface grafted polymer layers (brushes) induced by infiltration of nanoparticles that are attracted to the polymers in the layer. We systematically compare two different polymer brush geometries: one where the polymer chains are grafted to a planar surface and the other where the chains are grafted to the inside of a cylindrical nanochannel. We perform a comprehensive study of the effects of the material parameters such as the polymer chain length, chain grafting density, nanoparticle size, strength of attraction between nanoparticles and polymer monomers, and, in the case of the cylindrically grafted brush, the radius of the cylinder. We find a very general behavioral motif for all geometries and parameter values: the height of the polymer brush is non-monotonic in the nanoparticle concentration in solution. As the nanoparticle concentration increases, the brush height first decreases and after passing through a minimum value begins to increase, resulting in the swelling of the nanoparticle infused brush. These morphological features may be useful for devising tunable "smart" nano-devices whose effective dimensions can be reversibly and precisely adjusted by changing the nanoparticle concentration in solution. The results of approximate Self-Consistent Field Theory (SCFT) calculations, applicable in the regime of strong brush stretching, are compared to the simulation results. The SCFT calculations are found to be qualitatively, even semi-quantitatively, accurate when applied within their intended regime of validity, and provide a useful and efficient tool for modeling such materials.

  5. Study of Systems Using Inertia Wheels for Precise Attitude Control of a Satellite

    NASA Technical Reports Server (NTRS)

    White, John S.; Hansen, Q. Marion

    1961-01-01

    Systems using inertia wheels are evaluated in this report to determine their suitability for precise attitude control of a satellite and to select superior system configurations. Various possible inertia wheel system configurations are first discussed in a general manner. Three of these systems which appear more promising than the others are analyzed in detail, using the Orbiting Astronomical Observatory as an example. The three systems differ from each other only by the method of damping, which is provided by either a rate gyro, an error-rate network, or a tachometer in series with a high-pass filter. An analytical investigation which consists of a generalized linear analysis, a nonlinear analysis using the switching-time method, and an analog computer study shows that all three systems are theoretically capable of producing adequate response and also of maintaining the required pointing accuracy for the Orbiting Astronomical Observatory of plus or minus 0.1 second of arc. Practical considerations and an experimental investigation show, however, that the system which uses an error-rate network to provide damping is superior to the other two systems. The system which uses a rate gyro is shown to be inferior because the threshold level causes a significant amount of limit-cycle operation, and the system which uses a tachometer with a filter is shown to be inferior because a device with the required dynamic range of operation does not appear to be available. The experimental laboratory apparatus used to investigate the dynamic performance of the systems is described, and experimental results are included to show that under laboratory conditions with relatively large extraneous disturbances, a dynamic tracking error of less than plus or minus 0.5 second of arc was obtained.

  6. Hardware-In-The-Loop Testing of Continuous Control Algorithms for a Precision Formation Flying Demonstration Mission

    NASA Technical Reports Server (NTRS)

    Naasz, Bo J.; Burns, Richard D.; Gaylor, David; Higinbotham, John

    2004-01-01

    A sample mission sequence is defined for a low earth orbit demonstration of Precision Formation Flying (PFF). Various guidance navigation and control strategies are discussed for use in the PFF experiment phases. A sample PFF experiment is implemented and tested in a realistic Hardware-in-the-Loop (HWIL) simulation using the Formation Flying Test Bed (FFTB) at NASA's Goddard Space Flight Center.

  7. Control of large space structures: Status report on achievements and current problems

    NASA Technical Reports Server (NTRS)

    Lyons, M. G.; Aubrun, J. N.

    1983-01-01

    The objectives, state-of-the-art, and problems of large space structures control are outlined. The general objectives range from basic deployment and maneuvering, where some vibration modes may be suppressed, to disturbance rejection for very high performance imaging applications. The controls selected generally must produce some combination of eigenvalue/eigenvector and loads modification in order to achieve the mission objectives. An experiment illustrating the dynamic control of a suspended circular plate is described. Analysis methods used in system modelling, signal processing, and process control and monitoring are discussed. Sensor and actuator performance are assessed.

  8. How to Compute a Slot Marker - Calculation of Controller Managed Spacing Tools for Efficient Descents with Precision Scheduling

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas

    2012-01-01

    This paper describes the underlying principles and algorithms for computing the primary controller managed spacing (CMS) tools developed at NASA for precisely spacing aircraft along efficient descent paths. The trajectory-based CMS tools include slot markers, delay indications and speed advisories. These tools are one of three core NASA technologies integrated in NASAs ATM technology demonstration-1 (ATD-1) that will operationally demonstrate the feasibility of fuel-efficient, high throughput arrival operations using Automatic Dependent Surveillance Broadcast (ADS-B) and ground-based and airborne NASA technologies for precision scheduling and spacing.

  9. Effortful Control and Impulsivity as Concurrent and Longitudinal Predictors of Academic Achievement

    ERIC Educational Resources Information Center

    Valiente, Carlos; Eisenberg, Nancy; Spinrad, Tracy L.; Haugen, Rg; Thompson, Marilyn S.; Kupfer, Anne

    2013-01-01

    The goal of this study was to test if both effortful control (EC) and impulsivity, a reactive index of temperament, uniquely predict adolescents' academic achievement, concurrently and longitudinally (Time 1: "N" = 168, X-bar[subscript age] = 12 years). At Time 1, parents and teachers reported on students' EC and impulsivity.…

  10. Examining Perceived Control Level and Instability as Predictors of First-Year College Students' Academic Achievement

    ERIC Educational Resources Information Center

    Stupnisky, Robert H.; Perry, Raymond P.; Hall, Nathan C.; Guay, Frederic

    2012-01-01

    The aim of the present study was to examine the intraindividual level and instability of perceived academic control (PC) among first-year college students, and their predictive effects on academic achievement. Two studies were conducted measuring situational (state) PC on different schedules: Study 1 (N = 242) five times over a 6-month period and…

  11. Locus of Control in Achievement and Affiliation (MMCS) as Related to Pathologies.

    ERIC Educational Resources Information Center

    Childers, John; Lao, Rosina C.

    The Multidimensional-Multiattributional Causality Scale (MMCS) is a goal-specific scale developed to assess locus of control in the areas of achievement and affiliation. The relationship between the MMCS and feelings of depression, hopelessness, and perceived stress was examined to validate the MMCS and determine if specific expectancies take…

  12. On-Line Tutoring for Math Achievement Testing: A Controlled Evaluation

    ERIC Educational Resources Information Center

    Beal, Carole R.; Walles, Rena; Arroyo, Ivon; Woolf, Beverly P.

    2007-01-01

    We report the results of a controlled evaluation of an interactive on-line tutoring system for high school math achievement test problem solving. High school students (N = 202) completed a math pre-test and were then assigned by teachers to receive interactive on-line multimedia tutoring or their regular classroom instruction. The on-line tutored…

  13. Autonomy Support versus Psychological Control, Perfectionism, and Taiwanese Adolescents' Achievement Goals

    ERIC Educational Resources Information Center

    Shih, Shu-Shen

    2013-01-01

    The author attempted to explore potential antecedents of achievement goals and relations of teacher and parental autonomy support versus psychological control to Taiwanese adolescents' perfectionistic tendencies. A total of 512 eighth-grade students completed self-reported questionnaires assessing variables of interest. Results indicated that…

  14. Training Theory of Mind and Executive Control: A Tool for Improving School Achievement?

    ERIC Educational Resources Information Center

    Kloo, Daniela; Perner, Josef

    2008-01-01

    In the preschool years, there are marked improvements in theory of mind (ToM) and executive functions. And, children's competence in these two core cognitive domains is associated with their academic achievement. Therefore, training ToM and executive control could be a valuable tool for improving children's success in school. This article reviews…

  15. The Effect of Inhibitory Control on General Mathematics Achievement and Fraction Comparison in Middle School Children

    ERIC Educational Resources Information Center

    Gómez, David Maximiliano; Jiménez, Abelino; Bobadilla, Roberto; Reyes, Cristián; Dartnell, Pablo

    2015-01-01

    Individual differences in inhibitory control have been shown to relate to general mathematics achievement, but whether this relation varies for specific areas within mathematics is a question that remains open. Here, we evaluate if inhibitory processes play a specific role in the particular case of fraction comparison, where learners must ignore…

  16. Diagnosis, Remediation, and Locus of Control: Effects on Immediate and Retained Achievement and Attitudes.

    ERIC Educational Resources Information Center

    Saunders-Harris, Ramona; Yeany, Russell H.

    1981-01-01

    Subjects were assessed for locus of control and experienced either: no diagnosis; diagnosis; or, diagnosis and remediation. Immediate achievement was measured twice during the experiment; retention was measured 30 days later. Findings suggest that diagnostic or diagnostic/remedial instruction is effective in increasing middle school science…

  17. Tangential torque effects on the control of grip forces when holding objects with a precision grip.

    PubMed

    Kinoshita, H; Bäckström, L; Flanagan, J R; Johansson, R S

    1997-09-01

    difference between the employed normal force and the slip force, was relatively small and constant across all tangential force and torque levels except at small torques (< 10 N x mm). There was no difference in safety margin between the digits. In conclusion, tangential torque strongly influences the normal force required for grasp stability. When controlling normal force, people take into account, in a precise fashion, the slip force reflecting both tangential force and tangential torque and their interaction as well as the current frictional condition in the object-digit interface. PMID:9310447

  18. Role of Parenting Style in Achieving Metabolic Control in Adolescents With Type 1 Diabetes

    PubMed Central

    Shorer, Maayan; David, Ravit; Schoenberg-Taz, Michal; Levavi-Lavi, Ifat; Phillip, Moshe; Meyerovitch, Joseph

    2011-01-01

    OBJECTIVE To examine the role of parenting style in achieving metabolic control and treatment adherence in adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS Parents of 100 adolescents with type 1 diabetes completed assessments of their parenting style and sense of helplessness. Parents and patients rated patient adherence to the treatment regimen. Glycemic control was evaluated by HbA1c values. RESULTS An authoritative paternal parenting style predicted better glycemic control and adherence in the child; a permissive maternal parenting style predicted poor adherence. A higher sense of helplessness in both parents predicted worse glycemic control and lesser adherence to treatment. Parental sense of helplessness was a significant predictor of diabetes control after correcting for other confounders (patient age, sex, and treatment method). CONCLUSIONS An authoritative nonhelpless parenting style is associated with better diabetes control in adolescents. Paternal involvement is important in adolescent diabetes management. These results have implications for psychological interventions. PMID:21788643

  19. Impact of precision application of ammonium nonanoate on weed control efficacy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision application of herbicides is important to vegetable producers because there are a limited number of herbicides available and the potential for crop injury. Racer (ammonium nonanoate) is a contact herbicide labeled for food use with efforts underway to label it as a herbicide for organical...

  20. Report on a computer-controlled automatic test platform for precision RF cavity characterizations

    NASA Astrophysics Data System (ADS)

    Chen, X.; Sanjari, M. S.; Piotrowski, J.; Hülsmann, P.; Litvinov, Yu A.; Nolden, F.; Steck, M.; Stöhlker, Th

    2015-11-01

    An automated test platform aiming at accurate and efficient cavity characterizations has recently been set up at GSI, Darmstadt. In this proceeding the composition of such a system, on both hardware and software sides, is described in detail. The amount of necessary human work is significantly reduced to the minimum, while the measurement precision is improved considerably.

  1. Impact of precision applications of ammonium nonanoate on weed control efficacy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many factors contribute to the successful application of herbicides, including the herbicide’s mode of action, nozzle selection, application rate, application volume, weed species and weed maturity. The precision application of herbicides is especially important to commercial vegetable producers be...

  2. Dot Display Affects Approximate Number System Acuity and Relationships with Mathematical Achievement and Inhibitory Control

    PubMed Central

    Norris, Jade Eloise; Castronovo, Julie

    2016-01-01

    Much research has investigated the relationship between the Approximate Number System (ANS) and mathematical achievement, with continued debate surrounding the existence of such a link. The use of different stimulus displays may account for discrepancies in the findings. Indeed, closer scrutiny of the literature suggests that studies supporting a link between ANS acuity and mathematical achievement in adults have mostly measured the ANS using spatially intermixed displays (e.g. of blue and yellow dots), whereas those failing to replicate a link have primarily used spatially separated dot displays. The current study directly compared ANS acuity when using intermixed or separate dots, investigating how such methodological variation mediated the relationship between ANS acuity and mathematical achievement. ANS acuity was poorer and less reliable when measured with intermixed displays, with performance during both conditions related to inhibitory control. Crucially, mathematical achievement was significantly related to ANS accuracy difference (accuracy on congruent trials minus accuracy on incongruent trials) when measured with intermixed displays, but not with separate displays. The findings indicate that methodological variation affects ANS acuity outcomes, as well as the apparent relationship between the ANS and mathematical achievement. Moreover, the current study highlights the problem of low reliabilities of ANS measures. Further research is required to construct ANS measures with improved reliability, and to understand which processes may be responsible for the increased likelihood of finding a correlation between the ANS and mathematical achievement when using intermixed displays. PMID:27195749

  3. High-Achieving High School Students and Not so High-Achieving College Students: A Look at Lack of Self-Control, Academic Ability, and Performance in College

    ERIC Educational Resources Information Center

    Honken, Nora B.; Ralston, Patricia A. S.

    2013-01-01

    This study investigated the relationship among lack of self-control, academic ability, and academic performance for a cohort of freshman engineering students who were, with a few exceptions, extremely high achievers in high school. Structural equation modeling analysis led to the conclusion that lack of self-control in high school, as measured by…

  4. High-Precision Time Delay Control with Continuous Phase Shifter for Pump-Probe Experiments Using Synchrotron Radiation Pulses

    SciTech Connect

    Tanaka, Yoshihito; Ohshima, Takashi; Moritomo, Yutaka; Tanaka, Hitoshi; Takata, Masaki

    2010-06-23

    Brilliant pulsed x-ray synchrotron radiation (SR) is useful for pump-probe experiment such as time-resolved x-ray diffraction, x-ray absorption fine structure, and x-ray spectroscopy. For laser pump-SR x-ray probe experiments, short pulsed lasers are generally synchronized to the SR master oscillator controlling the voltage for acceleration of electron bunches in an accelerator, and the interval between the laser and the SR pulses is changed around the time scale of target phenomenon. Ideal delay control produces any time delay as keeping the time-precision and pointing-stability of optical pulses at a sample position. We constructed the time delay control module using a continuous phase shifter of radio frequency signal and a frequency divider, which can produce the delayed trigger pulses to the laser without degradation of the time precision and the pointing stability. A picoseconds time-resolved x-ray diffraction experiment was demonstrated at SPring-8 storage ring for fast lattice response by femtosecond pulsed laser irradiation, and suggested the possibility of accurate sound velocity measurement. A delay control unit operating with subpicosecond precision has also been designed for femtosecond pump-probe experiments using a free electron laser at SPring-8 campus.

  5. Flight control and landing precision in the nocturnal bee Megalopta is robust to large changes in light intensity.

    PubMed

    Baird, Emily; Fernandez, Diana C; Wcislo, William T; Warrant, Eric J

    2015-01-01

    Like their diurnal relatives, Megalopta genalis use visual information to control flight. Unlike their diurnal relatives, however, they do this at extremely low light intensities. Although Megalopta has developed optical specializations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual information to reliably control flight in the rainforest at night. It has been proposed that Megalopta gain extra sensitivity by summing visual information over time. While enhancing the reliability of vision, this strategy would decrease the accuracy with which they can detect image motion-a crucial cue for flight control. Here, we test this temporal summation hypothesis by investigating how Megalopta's flight control and landing precision is affected by light intensity and compare our findings with the results of similar experiments performed on the diurnal bumblebee Bombus terrestris, to explore the extent to which Megalopta's adaptations to dim light affect their precision. We find that, unlike Bombus, light intensity does not affect flight and landing precision in Megalopta. Overall, we find little evidence that Megalopta uses a temporal summation strategy in dim light, while we find strong support for the use of this strategy in Bombus. PMID:26578977

  6. Flight control and landing precision in the nocturnal bee Megalopta is robust to large changes in light intensity

    PubMed Central

    Baird, Emily; Fernandez, Diana C.; Wcislo, William T.; Warrant, Eric J.

    2015-01-01

    Like their diurnal relatives, Megalopta genalis use visual information to control flight. Unlike their diurnal relatives, however, they do this at extremely low light intensities. Although Megalopta has developed optical specializations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual information to reliably control flight in the rainforest at night. It has been proposed that Megalopta gain extra sensitivity by summing visual information over time. While enhancing the reliability of vision, this strategy would decrease the accuracy with which they can detect image motion—a crucial cue for flight control. Here, we test this temporal summation hypothesis by investigating how Megalopta's flight control and landing precision is affected by light intensity and compare our findings with the results of similar experiments performed on the diurnal bumblebee Bombus terrestris, to explore the extent to which Megalopta's adaptations to dim light affect their precision. We find that, unlike Bombus, light intensity does not affect flight and landing precision in Megalopta. Overall, we find little evidence that Megalopta uses a temporal summation strategy in dim light, while we find strong support for the use of this strategy in Bombus. PMID:26578977

  7. High school students' perceptions of EFL teacher control orientations and their English academic achievement.

    PubMed

    Kiany, Gholam Reza; Shayestefar, Parvaneh

    2011-09-01

    BACKGROUND. Theories distinguish between student-initiated and teacher-initiated regulation of students' learning activities, or between strong, shared, or loose teacher control during the completion of learning tasks. Empirical validations for such distinctions are scarce, however. AIM. The present study aimed at (a) investigating students' perceptions of control behaviours exhibited by their English teachers; and (b) exploring the contribution of different types of teacher control behaviours to students' cognitive outcomes (English Achievement). SAMPLE. The sample comprised 732 English as a Foreign Language (EFL) students studying in three major fields of high school (Mathematics, Natural Science, and Humanities). The participants (16-17 years of age) were selected from third-grade classes of 27 EFL teachers working in 25 high schools of 6 main different geographical regions in the Isfahan province, Iran. METHOD. To obtain a comprehensive picture of different control types exhibited by Iranian EFL teachers, the control subscales of the two existing questionnaires, i.e., the Questionnaire on Instructional Behaviours (QIB), adapted by Den Brok et al. (2004) and the Questionnaire on Lesson Activities (QLA) used by Den Brok (2001) were merged to form the Questionnaire of Teacher Control (QTC). The development of this Persian instrument involved several steps: translation and back translation by the researchers, one expert translator, and two EFL teachers; piloting; and a final administration of the questionnaire to the student sample. With respect to the second aim of the study, data regarding students' performances on the Standardized National English Achievement Tests were gathered from local educational offices and schools. RESULTS AND CONCLUSION. Statistical analyses supported acceptable reliability and validity of the instrument. A main factor structure with three types of teacher control (strong/high, shared/mid, and loose/low) was found to underlie students

  8. Optical pressure/acoustic sensor with precise Fabry-Perot cavity length control using angle polished fiber.

    PubMed

    Wang, Wenhui; Wu, Nan; Tian, Ye; Wang, Xingwei; Niezrecki, Christopher; Chen, Julie

    2009-09-14

    This paper presents a novel Fabry-Perot (FP) optical fiber pressure/acoustic sensor. It consists of two V-shaped grooves having different sized widths, a diaphragm on the surface of the larger V-groove, and a 45 degrees angle-polished fiber. The precision of FP cavity length is determined by the fabrication process of photolithography and anisotropic etching of a silicon crystal. Therefore, the cavity length can be controlled on the order of ten nm. Sensors were fabricated and tested. Test results indicate that the sensors' cavity lengths have been controlled precisely. The packaged sensor has demonstrated very good static and dynamic responses compared to a commercially available pressure sensor and a microphone. PMID:19770876

  9. One-nanometer-precision control of Al(2)O(3) nanoshells through a solution-based synthesis route.

    PubMed

    Zhang, Wei; Chi, Zi-Xiang; Mao, Wen-Xin; Lv, Rong-Wen; Cao, An-Min; Wan, Li-Jun

    2014-11-17

    Forming uniform metal oxide nanocoatings is a well-known challenge in the construction of core-shell type nanomaterials. Herein, by using buffer solution as a specific reaction medium, we demonstrate the possibility to grow thin nanoshells of metal oxides, typically Al2 O3 , on different kinds of core materials, forming a uniform surface-coating layer with thicknesses achieving one nanometer precision. The application of this methodology for the surface modification of LiCoO2 shows that a thin nanoshell of Al2 O3 can be readily tuned on the surface for an optimized battery performance. PMID:25336171

  10. Taking Control of Castleman Disease: Leveraging Precision Medicine Technologies to Accelerate Rare Disease Research

    PubMed Central

    Newman, Samantha Kass; Jayanthan, Raj K.; Mitchell, Grant W.; Carreras Tartak, Jossie A.; Croglio, Michael P.; Suarez, Alexander; Liu, Amy Y.; Razzo, Beatrice M.; Oyeniran, Enny; Ruth, Jason R.; Fajgenbaum, David C.

    2015-01-01

    Castleman disease (CD) is a rare and heterogeneous disorder characterized by lymphadenopathy that may occur in a single lymph node (unicentric) or multiple lymph nodes (multicentric), the latter typically occurring secondary to excessive proinflammatory hypercytokinemia. While a cohort of multicentric Castleman disease (MCD) cases are caused by Human Herpes Virus-8 (HHV-8), the etiology of HHV-8 negative, idiopathic MCD (iMCD), remains unknown. Breakthroughs in “omics” technologies that have facilitated the development of precision medicine hold promise for elucidating disease pathogenesis and identifying novel therapies for iMCD. However, in order to leverage precision medicine approaches in rare diseases like CD, stakeholders need to overcome several challenges. To address these challenges, the Castleman Disease Collaborative Network (CDCN) was founded in 2012. In the past 3 years, the CDCN has worked to transform the understanding of the pathogenesis of CD, funded and initiated genomics and proteomics research, and united international experts in a collaborative effort to accelerate progress for CD patients. The CDCN’s collaborative structure leverages the tools of precision medicine and serves as a model for both scientific discovery and advancing patient care. PMID:26604862

  11. How do different components of Effortful Control contribute to children’s mathematics achievement?

    PubMed Central

    Sánchez-Pérez, Noelia; Fuentes, Luis J.; Pina, Violeta; López-López, Jose A.; González-Salinas, Carmen

    2015-01-01

    This work sought to investigate the specific contribution of two different components of Effortful Control (EC) -attentional focusing (AF) and inhibitory control- to children’s mathematics achievement. The sample was composed of 142 children aged 9–12 year-old. EC components were measured through the Temperament in Middle Childhood Questionnaire (TMCQ; parent’s report); math achievement was measured via teacher’s report and through the standard Woodcock–Johnson test. Additionally, the contribution of other cognitive and socio-emotional processes was taken into account. Our results showed that only AF significantly contributed to the variance of children’s mathematics achievement; interestingly, mediational models showed that the relationship between effortful attentional self-regulation and mathematics achievement was mediated by academic peer popularity, as well as by intelligence and study skills. Results are discussed in the light of the current theories on the role of children’s self-regulation abilities in the context of school. PMID:26441758

  12. Professional training in the workplace: the role of achievement motivation and locus of control.

    PubMed

    Suárez-Álvarez, Javier; Campillo-Álvarez, Angela; Fonseca-Pedrero, Eduardo; García-Cueto, Eduardo; Muñiz, José

    2013-01-01

    The core objective of the present work is to explore the reasons why workers from different employment sectors join training courses to improve their job. To this end we assessed achievement motivation, locus of control and professional qualifications according to the participants' employment sector. The final sample consisted of 1460 active Spanish workers from four different employment sectors: services, catering, metal construction, and others. Of the sample, 40.1% were male and 59.9% female, with a mean age of 33.3 years (SD = 9.7). The results show that the new scale developed to assess achievement motivation, locus of control and workers' qualifications presents adequate psychometric characteristics. Statistically significant differences were found in relation to employment sector. The areas studied showed satisfactory levels of workers' effort and achievement motivation to perform their jobs, though their attitudes toward the training courses as a basis for improving their employability are varied. Workers in the catering sector had higher levels of external attribution and the lowest interest in training. Those in the service sector had higher levels of achievement motivation and effort at work. Future research should develop a joint program covering the public and private sectors for the modification of these beliefs, attitudes and attributions. PMID:23866230

  13. Perceived Control Mediates the Relations between Depressive Symptoms and Academic Achievement in Adolescence.

    PubMed

    Moè, Angelica

    2015-01-01

    The present research examined the protective role played by perceived control in the relation between depressive symptoms and academic achievement in adolescence. A sample of 218 adolescents aged 11 to 16 filled in questionnaires to assess self-reported depressive symptoms and three factors tied with Perceived Control (PC): self-regulated learning strategies use, effort attribution, and perceived competence. Grade Point Average (GPA) was considered as a measure of academic achievement. A path model showed that the relation between GPA and depressive symptoms is mediated by PC (p<.05), and became non-significant when PC is considered. The discussion stresses the need to take into account the strategic and motivational factors favouring learning in planning programmes to prevent and treat depressive symptoms in adolescence. PMID:26377348

  14. An Active Suspension Controller Achieving the Best Ride Comfort at Any Specified Location on A Vehicle

    NASA Astrophysics Data System (ADS)

    Oya, Masahiro; Harada, Hiroshi; Araki, Yoshiaki

    In this paper, a new active suspension control scheme is developed so that ride comfort becomes best at any specified location on vehicle body. To achieve this end, two ideal vehicles are designed in which ride comfort becomes best at each different location. Then, linearly combining the two ideal vehicles, a combined ideal vehicle is constructed. It should be noted that we can easily force ride comfort at a specified location become best in the proposed combined ideal vehicle by setting only one design parameter. To achieve the good property stated above in actual vehicles, a robust tracking controller is proposed. It is shown by carrying out numerical simulations that ride comfort at a specified location can be easily improved in the closed loop system using the proposed combined ideal vehicle.

  15. Precise control of caval and hepatic vessels: Surgical technique to treat level III caval thrombus concomitant to renal cell carcinoma

    PubMed Central

    Chen, Ming; Xu, Bin; Liu, Ning; Jiang, Hua; Wang, Yiduo; Yang, Yu; Zhang, Xiaowen; Sun, Chao; Liu, Jing; Zhu, Weidong; Chen, Shuqiu

    2015-01-01

    Introduction: We investigated the surgical techniques, safety, and prevention of complications of nephrectomy and removal of tumour thrombus for treating level III inferior vena cava (IVC) concomitant to renal cell carcinoma (RCC). We did this by precise controlling IVC and hepatic vessels without a vascular bypass. Methods: In this series, we included 5 patients with level III IVC tumour thrombus below the hepatic vein concomitant to RCC. After precisely controlling the IVC and hepatic vessels, we then removed the thrombus en bloc with the renal vein. Blood loss volume, IVC clamping time, hypotension time, resuscitation, cardiocerebrovascular complications, and postoperative organ dysfunction were observed. Results: Surgery was successfully performed without perioperative death. Blood loss volume was 900 to 1500 mL, operation time was 165 to 250 minutes, vascular clamping time was 8 to 12 minutes, and intraoperative hypotension time was 9 to 12 minutes. Serious perioperative complications were not observed. Local recurrence was not observed during the 9 to 24 months of follow-up. One patient exhibited disease-free survival, 3 developed lung or liver metastasis, and 1 died 11 months after surgery. Conclusion: Precise control of IVC and hepatic pedicle vessels, without vascular bypass, is a safe and effective surgical treatment for level III tumor thrombus below the hepatic vein concomitant to RCC. The procedure was conducted without increased risks of intraoperative hypotensive shock, difficult resuscitation, pulmonary embolism, and multiple organ dysfunctions. PMID:26600890

  16. Clinical importance of achieving biochemical control with medical therapy in adult patients with acromegaly

    PubMed Central

    Christofides, Elena A

    2016-01-01

    In acromegaly, achieving biochemical control (growth hormone [GH] level <1.0 ng/mL and age- and sex-normalized levels of insulin-like growth factor 1 [IGF-1]) through timely diagnosis and appropriate treatment provides an opportunity to improve patient outcomes. Diagnosis of acromegaly is challenging because it is rooted in observing subtle clinical manifestations, and it is typical for acromegaly to evolve for up to 10 years before it is recognized. This results in chronic exposure to elevated levels of GH and IGF-1 and delay in patients receiving appropriate treatment, which consequently increases mortality risk. In this review, the clinical impact of elevated GH and IGF-1 levels, the effectiveness of current therapies, and the potential role of novel treatments for acromegaly will be discussed. Clinical burden of acromegaly and benefits associated with management of GH and IGF-1 levels will be reviewed. Major treatment paradigms in acromegaly include surgery, medical therapy, and radiotherapy. With medical therapies, such as somatostatin analogs, dopamine agonists, and GH receptor antagonists, a substantial proportion of patients achieve reduced GH and normalized IGF-1 levels. In addition, signs and symptoms, quality of life, and comorbidities have also been reported to improve to varying degrees in patients who achieve biochemical control. Currently, there are several innovative therapies in development to improve patient outcomes, patient use, and access. Timely biochemical control of acromegaly ensures that the patient can ultimately improve morbidity and mortality from this disease and its extensive consequences. PMID:27471378

  17. Use a linear model to achieve stable composition control in a naphtha splitter

    SciTech Connect

    Karpe, P.

    1997-01-01

    The following two points using dual composition control in a naphtha splitter are emphasized: while literature provides general guidelines for design of control systems for distillation columns, each column is unique in terms of dynamic and steady state behavior. Multivariable control analytical tools, such as RGA and SVD, coupled with rigorous steady state simulations, can be effectively employed to achieve stable control in columns beset with severe loop interactions, and often in the absence of on-line analyzers, linear models representing the first order approximations of distillation columns can yield significant benefits. Such models are simple to understand, readily acceptable to operators, do not require special expertise to maintain, and therefore, offer high degree of reliability.

  18. Precisely Controlled Ultrathin Conjugated Polymer Films for Large Area Transparent Transistors and Highly Sensitive Chemical Sensors.

    PubMed

    Khim, Dongyoon; Ryu, Gi-Seong; Park, Won-Tae; Kim, Hyunchul; Lee, Myungwon; Noh, Yong-Young

    2016-04-01

    A uniform ultrathin polymer film is deposited over a large area with molecularlevel precision by the simple wire-wound bar-coating method. The bar-coated ultrathin films not only exhibit high transparency of up to 90% in the visible wavelength range but also high charge carrier mobility with a high degree of percolation through the uniformly covered polymer nanofibrils. They are capable of realizing highly sensitive multigas sensors and represent the first successful report of ethylene detection using a sensor based on organic field-effect transistors. PMID:26849096

  19. Precise Heat Control: What Every Scientist Needs to Know About Pyrolytic Techniques to Solve Real Problems

    NASA Technical Reports Server (NTRS)

    Devivar, Rodrigo

    2014-01-01

    The performance of a material is greatly influenced by its thermal and chemical properties. Analytical pyrolysis, when coupled to a GC-MS system, is a powerful technique that can unlock the thermal and chemical properties of almost any substance and provide vital information. At NASA, we depend on precise thermal analysis instrumentation for understanding aerospace travel. Our analytical techniques allow us to test materials in the laboratory prior to an actual field test; whether the field test is miles up in the sky or miles underground, the properties of any involved material must be fully studied and understood in the laboratory.

  20. Monolithic Single-Mode DFB Laser Array with Precise Wavelength Control for Optoelectronic Integration using an Equivalent Phase Shift Method

    NASA Astrophysics Data System (ADS)

    Li, Jingsi; Cheng, Julian; Microelectronics Research Center Team

    2013-03-01

    The integrated distributed feedback (DFB) laser array is a key component in photonic integrated circuits for wavelength-division multiplexing (WDM) system. However, it is difficult to precisely control the wavelength of individual lasers. When the rear facet of the laser is coated with a high-reflectivity mirror, a random phase change is introduced that shifts the lasing wavelength, making monolithic integration of a wavelength-controlled WDM array very difficult. To solve this problem, we propose a method to precisely control the lasing wavelength of DFB lasers over a wide range by introducing an equivalent phase shift in the cavity using sampled Bragg gratings, using wafer-scale optical lithography and requiring only coarse dimension control. The wavelength can be fine-tuned by applying different DC currents. It is shown that a WDM-DFB laser array with uniform wavelength spacing can be controlled accurately in this manner. Integrated arrays of single-mode DFB lasers for WDM systems can thus be fabricated in a low-cost manner without using low-throughput e-beam lithography, and is scalable for mass-manufacturing.

  1. Instrument parameters controlling retention precision in gradient elution reversed-phase liquid.

    PubMed

    Beyaza, Ayse; Fana, Wenzhe; Carr, Peter W; Schellinger, Adam P

    2014-12-01

    The precision of retention time in RPLC is important for compound identification, for setting peak integration time windows and in fundamental studies of retention. In this work, we studied the effect of temperature (T), initial (ϕo) and final mobile phase (ϕf) composition, gradient time (tG), and flow rate (F) on the retention time precision under gradient elution conditions for various types of low MW solutes. We determined the retention factor in pure water ( [Formula: see text] ) and the solute-dependent solvent strength (S) parameters of Snyder's linear solvent strength theory (LSST) as a function of temperature for three different groups of solutes. The effect of small changes in the chromatographic variables (T, ϕo, ϕf, tG and F) by use of the LSST gradient retention equation were estimated. Peaks at different positions in the chromatogram have different sensitivities to changes in these instrument parameters. In general, absolute fluctuations in retention time are larger at longer gradient times. Drugs showed less sensitivity to changes in temperature compared to relatively less polar solutes, non-ionogenic solutes. Surprisingly we observed that fluctuations in temperature, mobile phase composition and flow rate had less effect on retention time under gradient conditions as compared to isocratic conditions. Overall temperature and the initial mobile phase composition are the most important variables affecting retention reproducibility in gradient elution chromatography. PMID:25459648

  2. Instrument Parameters Controlling Retention Precision in Gradient Elution Reversed-Phase Liquid Chromatography

    PubMed Central

    Beyaz, Ayse; Fan, Wenzhe; Carr, Peter W.; Schellinger, Adam P.

    2014-01-01

    The precision of retention time in RPLC is important for compound identification, for setting peak integration time windows and in fundamental studies of retention. In this work, we studied the effect of temperature (T), initial (ϕ0) and final mobile phase (ϕf)composition, gradient time (tG), and flow rate (F) on the retention time precision under gradient elution conditions for various types of low MW solutes. We determined the retention factor in pure water (k′w) and the solute-dependent solvent strength (S) parameters of Snyder's linear solvent strength theory (LSST) as a function of temperature for three different groups of solutes. The effect of small changes in the chromatographic variables (T, ϕ0, ϕf, tG and F) by use of the LSST gradient retention equation were estimated. Peaks at different positions in the chromatogram have different sensitivities to changes in these instrument parameters. In general, absolute fluctuations in retention time are larger at longer gradient times. Drugs showed less sensitivity to changes in temperature compared to relatively less polar solutes, non-ionogenic solutes. Surprisingly we observed that fluctuations in temperature, mobile phase composition and flow rate had less effect on retention time under gradient conditions as compared to isocratic conditions. Overall temperature and the initial mobile phase composition are the more important variables affecting retention reproducibility in gradient elution chromatography. PMID:25459648

  3. Active member control of a precision structure with an H(infinity) performance objective

    NASA Technical Reports Server (NTRS)

    Fanson, J. L.; Chu, C.-C.; Smith, R. S.; Anderson, E. H.

    1990-01-01

    This paper addresses the noncollocated control of active structures using active structural elements. A top level architecture for active structures is presented, and issues pertaining to robust control of structures are discussed. Controllers optimized for an H sub inf performance specification are implemented on a test structure and the results are compared with analytical predictions. Directions for further research are identified.

  4. Transform methods for precision continuum and control models of flexible space structures

    NASA Technical Reports Server (NTRS)

    Lupi, Victor D.; Turner, James D.; Chun, Hon M.

    1991-01-01

    An open loop optimal control algorithm is developed for general flexible structures, based on Laplace transform methods. A distributed parameter model of the structure is first presented, followed by a derivation of the optimal control algorithm. The control inputs are expressed in terms of their Fourier series expansions, so that a numerical solution can be easily obtained. The algorithm deals directly with the transcendental transfer functions from control inputs to outputs of interest, and structural deformation penalties, as well as penalties on control effort, are included in the formulation. The algorithm is applied to several structures of increasing complexity to show its generality.

  5. Concepts for Life Cycle Cost Control Required to Achieve Space Transportation Affordability and Sustainability

    NASA Technical Reports Server (NTRS)

    Rhodes, Russel E.; Zapata, Edgar; Levack, Daniel J. H.; Robinson, John W.; Donahue, Benjamin B.

    2009-01-01

    Cost control must be implemented through the establishment of requirements and controlled continually by managing to these requirements. Cost control of the non-recurring side of life cycle cost has traditionally been implemented in both commercial and government programs. The government uses the budget process to implement this control. The commercial approach is to use a similar process of allocating the non-recurring cost to major elements of the program. This type of control generally manages through a work breakdown structure (WBS) by defining the major elements of the program. If the cost control is to be applied across the entire program life cycle cost (LCC), the approach must be addressed very differently. A functional breakdown structure (FBS) is defined and recommended. Use of a FBS provides the visibifity to allow the choice of an integrated solution reducing the cost of providing many different elements of like function. The different functional solutions that drive the hardware logistics, quantity of documentation, operational labor, reliability and maintainability balance, and total integration of the entire system from DDT&E through the life of the program must be fully defined, compared, and final decisions made among these competing solutions. The major drivers of recurring cost have been identified and are presented and discussed. The LCC requirements must be established and flowed down to provide control of LCC. This LCC control will require a structured rigid process similar to the one traditionally used to control weight/performance for space transportation systems throughout the entire program. It has been demonstrated over the last 30 years that without a firm requirement and methodically structured cost control, it is unlikely that affordable and sustainable space transportation system LCC will be achieved.

  6. Study of a Simulation Tool to Determine Achievable Control Dynamics and Control Power Requirements with Perfect Tracking

    NASA Technical Reports Server (NTRS)

    Ostroff, Aaron J.

    1998-01-01

    This paper contains a study of two methods for use in a generic nonlinear simulation tool that could be used to determine achievable control dynamics and control power requirements while performing perfect tracking maneuvers over the entire flight envelope. The two methods are NDI (nonlinear dynamic inversion) and the SOFFT(Stochastic Optimal Feedforward and Feedback Technology) feedforward control structure. Equivalent discrete and continuous SOFFT feedforward controllers have been developed. These equivalent forms clearly show that the closed-loop plant model loop is a plant inversion and is the same as the NDI formulation. The main difference is that the NDI formulation has a closed-loop controller structure whereas SOFFT uses an open-loop command model. Continuous, discrete, and hybrid controller structures have been developed and integrated into the formulation. Linear simulation results show that seven different configurations all give essentially the same response, with the NDI hybrid being slightly different. The SOFFT controller gave better tracking performance compared to the NDI controller when a nonlinear saturation element was added. Future plans include evaluation using a nonlinear simulation.

  7. Multi-mode sliding mode control for precision linear stage based on fixed or floating stator

    NASA Astrophysics Data System (ADS)

    Fang, Jiwen; Long, Zhili; Wang, Michael Yu; Zhang, Lufan; Dai, Xufei

    2016-02-01

    This paper presents the control performance of a linear motion stage driven by Voice Coil Motor (VCM). Unlike the conventional VCM, the stator of this VCM is regulated, which means it can be adjusted as a floating-stator or fixed-stator. A Multi-Mode Sliding Mode Control (MMSMC), including a conventional Sliding Mode Control (SMC) and an Integral Sliding Mode Control (ISMC), is designed to control the linear motion stage. The control is switched between SMC and IMSC based on the error threshold. To eliminate the chattering, a smooth function is adopted instead of a signum function. The experimental results with the floating stator show that the positioning accuracy and tracking performance of the linear motion stage are improved with the MMSMC approach.

  8. High precision tracking control of a servo gantry with dynamic friction compensation.

    PubMed

    Zhang, Yangming; Yan, Peng; Zhang, Zhen

    2016-05-01

    This paper is concerned with the tracking control problem of a voice coil motor (VCM) actuated servo gantry system. By utilizing an adaptive control technique combined with a sliding mode approach, an adaptive sliding mode control (ASMC) law with friction compensation scheme is proposed in presence of both frictions and external disturbances. Based on the LuGre dynamic friction model, a dual-observer structure is used to estimate the unmeasurable friction state, and an adaptive control law is synthesized to effectively handle the unknown friction model parameters as well as the bound of the disturbances. Moreover, the proposed control law is also implemented on a VCM servo gantry system for motion tracking. Simulations and experimental results demonstrate good tracking performance, which outperform traditional control approaches. PMID:26928515

  9. The Feasibility of the Disturbance Accommodating Controller for Precision Antenna Pointing

    NASA Technical Reports Server (NTRS)

    Gresham, L. L.; Lansing, F. L.; Guiar, C. N.

    1988-01-01

    The objective of this study is to investigate the feasibility of a pointing (position loop) controller for the NASA-JPL Deep Space Network (DSN) antennas using the Disturbance Accommodating Control (DAC) theory. A model that includes state dependent disturbances was developed, and an example demonstrating the noise estimator is presented as an initial phase in the controller design. The goal is to improve pointing accuracy by the removal of the systematic errors caused by the antenna misalignment as well as sensor noise and random wind and thermal disturbances. Preliminary simulation results show that the DAC technique is successful in both cancelling the imposed errors and maintaining an optimal control policy.

  10. Model identification of terfenol-D magnetostrictive actuator for precise positioning control

    NASA Astrophysics Data System (ADS)

    Saleem, Ashraf; Ghodsi, Mojtaba; Mesbah, Mostefa; Ozer, Abdullah

    2016-04-01

    Feedback control strategies are desirable for disturbance rejection of human-induced vibrations in civil engineering structures as human walking forces cannot easily be measured. In relation to human-induced vibration control studies, most past researches have focused on floors and footbridges and the widely used linear controller implemented in the trials has been the direct velocity feedback (DVF) scheme. With appropriate compensation to enhance its robustness, it has been shown to be effective at damping out the problematic modes of vibration of the structures in which the active vibration control systems have been implemented. The work presented here introduces a disturbance observer (DOB) that is used with an outer-loop DVF controller. Results of analytical studies presented in this work based on the dynamic properties of a walkway bridge structure demonstrate the potential of this approach for enhancing the vibration mitigation performance offered by a purely DVF controller. For example, estimates of controlled frequency response functions indicate improved attenuation of vibration around the dominant frequency of the walkway bridge structure as well as at higher resonant frequencies. Controlled responses from three synthesized walking excitation forces on a walkway bridge structure model show that the inclusion of the disturbance observer with an outer loop DVF has potential to improve on the vibration mitigation performance by about 3.5% at resonance and 6-10% off-resonance. These are realised with hard constraints being imposed on the low frequency actuator displacements.

  11. High-precision single-input control of relative motion in spacecraft formation

    NASA Astrophysics Data System (ADS)

    Guerman, Anna; Ovchinnikov, Michael; Smirnov, Georgi; Trofimov, Sergey

    2014-01-01

    A Newton-type method is proposed to improve the accuracy of control for relative motion of two satellites in close formation. We assume that the deputy satellite is equipped with a passive attitude control system that provides one-axis stabilization, and one or two orbit control thrusters are installed along the stabilized axis. Previous studies show that it is possible to construct periodic relative trajectories both in case of passive magnetic and spin stabilization. However, the accuracy of the numerically obtained control is quite low due to modeling errors caused by linearization of the equations of relative motion. Therefore, a correction procedure is required to compensate for nonlinear effects. To this end we suggest a recently developed algorithm based on the Newton method for solving nonlinear systems with geometric constraints. Being implemented, this algorithm allows decreasing the modeling error by up to ten times. The previously found control and trajectory of the linearized system are used as initial approximations.

  12. Achieving glycemic control in special populations in hospital: perspectives in practice.

    PubMed

    Cheng, Alice Y Y

    2014-04-01

    Achieving and maintaining glycemic control in patients with diabetes admitted to hospital is challenging because of the many competing factors of nutrition, pharmacotherapy and other patient-related and systemic factors. For patients receiving enteral or parenteral feeding, eating irregularly or receiving glucocorticoid therapy, the challenges are even greater. The basic principles to follow when managing glycemia in these populations are as follows: 1) Recognition of those at risk for hyperglycemia; 2) frequent bedside glucose monitoring; 3) a proactive approach with routine insulin administration based on the predicted glucose patterns; 4) constant reassessment of the glycemic status and titration of the routine insulin accordingly. PMID:24690508

  13. Precision Optical Gauging With Image Sensing Camera And Programmable Microprocessor Controller

    NASA Astrophysics Data System (ADS)

    West, , Perry; Mauritz, Karl

    1980-08-01

    An effective approach to the design of a line scan camera controller is covered in this paper. Primary features of the controller, other than the microprocessor operation, which are covered, include camera data compression and presentation to the microprocessor, mathematical capability for efficient mensuration, real-time capability for machine and process interface, and steps to make the hardware more versatile in order to complement the flexibility of software. A detailed example is given in the application of the controller to the production sizing and grading of spherical bearing rollers under the dual constraints of high thruput (2400 rollers/hour) and high accuracy (50 microinches).

  14. High precision active nutation control for a flexible momentum biased spacecraft

    NASA Technical Reports Server (NTRS)

    Laskin, R. A.; Kopf, E. H.

    1984-01-01

    The controller design for the Solar Dynamics Observatory (SDO) is presented. SDO is a momentum biased spacecraft with three flexible appendages. Its primary scientific instrument, the solar oscillations imager (SOI), is rigidly attached to the spacecraft bus and has arc-second pointing requirements. Meeting these requirements necessitates the use of an active nutation controller (ANC) which is here mechanized with a small reaction wheel oriented along a bus transverse axis. The ANC does its job by orchestrating the transfer of angular momentum out of the bus transverse axes and into the momentum wheel. A simulation study verifies that the controller provides quick, stable, and accurate response.

  15. A Nonlinear, Six-Degree of Freedom Precision Formation Control Algorithm, Based on Restricted Three Body Dynamics

    NASA Technical Reports Server (NTRS)

    Bauer, Frank (Technical Monitor); Luquette, Richard J.; Sanner, Robert M.

    2003-01-01

    Precision Formation Flying is an enabling technology for a variety of proposed space-based observatories, including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), the associated MAXIM pathfinder mission, and the Stellar Imager. An essential element of the technology is the control algorithm. This paper discusses the development of a nonlinear, six-degree of freedom (6DOF) control algorithm for maintaining the relative position and attitude of a spacecraft within a formation. The translation dynamics are based on the equations of motion for the restricted three body problem. The control law guarantees the tracking error convergences to zero, based on a Lyapunov analysis. The simulation, modelled after the MAXIM Pathfinder mission, maintains the relative position and attitude of a Follower spacecraft with respect to a Leader spacecraft, stationed near the L2 libration point in the Sun-Earth system.

  16. A non-destructive n-doping method for graphene with precise control of electronic properties via atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Han, Kyu Seok; Kalode, Pranav Y.; Koo Lee, Yong-Eun; Kim, Hongbum; Lee, Lynn; Sung, Myung Mo

    2016-02-01

    Graphene applications require high precision control of the Fermi level and carrier concentration via a nondestructive doping method. Here, we develop an effective n-doping technique using atomic layer deposition (ALD) of ZnO thin films on graphene through a reactive molecular layer. This ALD doping method is nondestructive, simple, and precise. The ZnO thin films on graphene are uniform, conformal, of good quality with a low density of pinholes, and finely tunable in thickness with 1 Å resolution. We demonstrate graphene transistor control in terms of the Dirac point, carrier density, and doping state as a function of the ZnO thickness. Moreover, ZnO functions as an effective thin-film barrier against air-borne water and oxygen on the graphene, resulting in extraordinary stability in air for graphene devices. ZnO ALD was also applied to other two-dimensional materials including MoS2 and WSe2, which substantially enhanced electron mobility.Graphene applications require high precision control of the Fermi level and carrier concentration via a nondestructive doping method. Here, we develop an effective n-doping technique using atomic layer deposition (ALD) of ZnO thin films on graphene through a reactive molecular layer. This ALD doping method is nondestructive, simple, and precise. The ZnO thin films on graphene are uniform, conformal, of good quality with a low density of pinholes, and finely tunable in thickness with 1 Å resolution. We demonstrate graphene transistor control in terms of the Dirac point, carrier density, and doping state as a function of the ZnO thickness. Moreover, ZnO functions as an effective thin-film barrier against air-borne water and oxygen on the graphene, resulting in extraordinary stability in air for graphene devices. ZnO ALD was also applied to other two-dimensional materials including MoS2 and WSe2, which substantially enhanced electron mobility. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08016a

  17. Improved device bonding performance: precise placement with appropriate thermal and atmospheric control

    NASA Astrophysics Data System (ADS)

    Avila, Robert; McLeod, Saul

    2009-02-01

    In any assembly, where two devices are to be precisely connected, the integrity and quality of this connection (bond) is a key factor in the overall performance of the final device. In micro-assembly and optoelectronics, this connection is typically gold to gold, solder, or epoxy bond. The chemistries can vary, but the critical issues remain the same. Placement accuracy is an important consideration and is normally the starting point for most bonding applications. In optoelectronics, the placement of a laser will be critical to its performance. Often edge-to-edge alignment is needed, which requires optical resolution of one micron or better. Laser bars have the added challenge of requiring this high optical resolution, but over distances of more than 10 millimeters. Equally important is what happens after a device has been aligned to a substrate ready for bonding. Both thermal and force parameters must be considered. Voiding in the material or oxidation during the soldering process all need to be minimized. This paper will look at recent innovations to improve the final bond. These innovations include temperature ramp rate, heated inert atmosphere and component uniformity. These processing techniques are particularly applicable in optoelectronics applications, such as laser diode and laser bar bonding.

  18. Esmolol in a case of severe tetanus. Adequate haemodynamic control achieved despite markedly elevated catecholamine levels.

    PubMed

    Beards, S C; Lipman, J; Bothma, P A; Joynt, G M

    1994-03-01

    A patient with severe tetanus, who had a sympathetic crisis while sedated with 30 mg/h diazepam and 30 mg/h morphine, is described. Satisfactory control of the haemodynamic crisis was achieved with bolus doses of esmolol to a total of 180 mg. A disturbing finding was that although there was adequate control of the tachycardia and hypertension, arterial catecholamine levels remained markedly elevated. Adrenaline levels of 531 pg/ml (normal 10-110 pg/ml) and noradrenaline levels of 1,036 pg/ml (normal 100-500 pg/ml) were recorded when the patient had a systolic arterial pressure of 110 mmHg and a heart rate of 97/min. The implications of this finding are discussed. PMID:11218441

  19. Development and precision position/force control of a new flexure-based microgripper

    NASA Astrophysics Data System (ADS)

    Yang, Yi-ling; Wei, Yan-ding; Lou, Jun-qiang; Xie, Feng-ran; Fu, Lei

    2016-01-01

    This paper presents the design, modeling and position/force control of a new piezo-driven microgripper with integrated position and force sensors. The structural design of the microgripper is based on double amplification mechanisms employing the bridge-type mechanism and the parallelogram mechanism. The microgripper can generate a large gripping range and pure translation of the gripping arm. Through the pseudorigid-body-model method, theoretical models are derived. By means of several finite-element analysis simulations, the optimal structural parameters for the microgripper are acquired and the theoretical models are analyzed and validated. Furthermore, to improve the performance of the microgripper, a new hybrid position/force control scheme employing a nonlinear fuzzy logic controller combined with an incremental proportional-integral controller is presented. The control scheme is capable of regulating the position and the gripping force of the microgripper simultaneously. Experimental investigation and validation were performed and the experimental results verify the effectiveness of the developed structural design and the proposed hybrid control scheme.

  20. Promotive effect of comprehensive management on achieving blood glucose control in senile type 2 diabetics.

    PubMed

    Yan, S-T; Li, C-X; Li, C-L; Li, J; Shao, Y-H; Liu, Y; Zhong, W-W; Fang, F-S; Sun, B-R; Tian, H

    2015-01-01

    The aim of this study was to evaluate the control of blood glucose and glycosylated hemoglobin A1c (HbA1c) and its influencing factors, in elderly type 2 diabetic mellitus (T2DM) patients undergoing comprehensive management. After years of comprehensive prevention of and control measures for diabetes, elderly T2DM patients who were receiving long-term health care were comprehensively evaluated through an annual physical examination. In addition to routine health examination, the patients were required to undergo HbA1c measurement. Among 688 patients, 652 were men and 36 were women, with a mean age of 78.2 ± 9.1 years. The average HbA1c was 6.6 ± 0.9%. A total of 50.6% of the patients had HbA1c <6.5%, whereas 76.3% had HbA1c <7.0%. Among all patients, 77.1, 46.4, 66.1, 67.8, 36.3, and 57.4% achieved the target total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), blood pressure, and body mass index (BMI) levels, respectively. The duration of disease and type of treatment, as well as the LDL, HDL, TG, BMI, and blood pressure levels, were significantly associated with HbA1c control. No patient was admitted because of ketoacidosis or hyperosmolar nonketotic diabetic coma in 10 years. Approximately half of the T2DM patients achieved the target HbA1c level. The more effective blood glucose control observed in our study compared with previous studies can be attributed to the effective monitoring of medical conditions and comprehensive management of patients. PMID:25966070

  1. The Control-Value Theory of Achievement Emotions: Assumptions, Corollaries, and Implications for Educational Research and Practice

    ERIC Educational Resources Information Center

    Pekrun, Reinhard

    2006-01-01

    This article describes the control-value theory of achievement emotions and its implications for educational research and practice. The theory provides an integrative framework for analyzing the antecedents and effects of emotions experienced in achievement and academic settings. It is based on the premise that appraisals of control and values are…

  2. A control system of mobile navigation robot for precise spraying based ultrasonic detecting and ARM embedded technologies

    NASA Astrophysics Data System (ADS)

    Tang, Xiuying; Li, Cuiling; Wang, Xiu; Yue, Xinpeng; Peng, Yankun

    2011-06-01

    This paper described a control system of mobile navigation robot for precision spraying in greenhouse environment, which were composed of main control module, motor driving module, ultrasonic detecting module and wirless remote control module. The hard circuits of control system were built. The main control module used ARM7TDMI-S-based LPC2210 micro-processing controller. The motor driving module consisted of voltage amplifier circuit based SN74LS245N and DM74LS244N chips, RC filter circuit, and HM-YZ-30 DC brush motor driver. The ultrasonic detecting module consisted of four standard ultrasonic ranging modules which were arranged on the four sides around the mobile navigation robot, and used GM8125 chip to expand serial communication interfaces. An obstacle-avoiding strategy and its algorithm were proposed and the control programs of mobile navigation robot were programmed. The mobile navigation robot for spraying can realize the actions such as starting and stopping, forward and backward moving, accelerate and decelerate motion, and right and left turn. Finally, the functional experiments of the mobile navigation robot were conducted in the laboratory environment. The results showed that the ultrasonic detecting distance of the robot was 50.5mm-1832.0mm and detecting blind zone was less than 50mm, the ultrasonic detecting angle of individual ultrasonic detecting module of robot was similar to U-shaped and its vaule was about 45.66°, and the moving path of navigation robot was approximately linear.

  3. The effect of acute treadmill walking on cognitive control and academic achievement in preadolescent children.

    PubMed

    Hillman, C H; Pontifex, M B; Raine, L B; Castelli, D M; Hall, E E; Kramer, A F

    2009-03-31

    The effect of an acute bout of moderate treadmill walking on behavioral and neuroelectric indexes of the cognitive control of attention and applied aspects of cognition involved in school-based academic performance were assessed. A within-subjects design included 20 preadolescent participants (age=9.5+/-0.5 years; eight female) to assess exercise-induced changes in performance during a modified flanker task and the Wide Range Achievement Test 3. The resting session consisted of cognitive testing followed by a cardiorespiratory fitness assessment to determine aerobic fitness. The exercise session consisted of 20 min of walking on a motor-driven treadmill at 60% of estimated maximum heart rate followed by cognitive testing once heart rate returned to within 10% of pre-exercise levels. Results indicated an improvement in response accuracy, larger P3 amplitude, and better performance on the academic achievement test following aerobic exercise relative to the resting session. Collectively, these findings indicate that single, acute bouts of moderately-intense aerobic exercise (i.e. walking) may improve the cognitive control of attention in preadolescent children, and further support the use of moderate acute exercise as a contributing factor for increasing attention and academic performance. These data suggest that single bouts of exercise affect specific underlying processes that support cognitive health and may be necessary for effective functioning across the lifespan. PMID:19356688

  4. THE EFFECT OF ACUTE TREADMILL WALKING ON COGNITIVE CONTROL AND ACADEMIC ACHIEVEMENT IN PREADOLESCENT CHILDREN

    PubMed Central

    Hillman, Charles H.; Pontifex, Matthew B.; Raine, Lauren B.; Castelli, Darla M.; Hall, Eric E.; Kramer, Arthur F.

    2009-01-01

    The effect of an acute bout of moderate treadmill walking on behavioral and neuroelectric indices of the cognitive control of attention and applied aspects of cognition involved in school-based academic performance were assessed. A within-subjects design included twenty preadolescent participants (Age = 9.5 ± 0.5 years; 8 female) to assess exercise-induced changes in performance during a modified flanker task and the Wide Range Achievement Test 3. The resting session consisted of cognitive testing followed by a cardiorespiratory fitness assessment to determine aerobic fitness. The exercise session consisted of 20 minutes of walking on a motor-driven treadmill at 60% of estimated maximum heart rate followed by cognitive testing once heart rate returned to within 10% of pre-exercise levels. Results indicated an improvement in response accuracy, larger P3 amplitude, and better performance on the academic achievement test following aerobic exercise relative to the resting session. Collectively, these findings indicate that single, acute bouts of moderately-intense aerobic exercise (i.e., walking) may improve the cognitive control of attention in preadolescent children, and further supports the use of moderate acute exercise as a contributing factor for increasing attention and academic performance. These data suggest that single bouts of exercise affect specific underlying processes that support cognitive health and may be necessary for effective functioning across the lifespan. PMID:19356688

  5. Design of state-feedback controllers including sensitivity reduction, with applications to precision pointing

    NASA Technical Reports Server (NTRS)

    Hadass, Z.

    1974-01-01

    The design procedure of feedback controllers was described and the considerations for the selection of the design parameters were given. The frequency domain properties of single-input single-output systems using state feedback controllers are analyzed, and desirable phase and gain margin properties are demonstrated. Special consideration is given to the design of controllers for tracking systems, especially those designed to track polynomial commands. As an example, a controller was designed for a tracking telescope with a polynomial tracking requirement and some special features such as actuator saturation and multiple measurements, one of which is sampled. The resulting system has a tracking performance comparing favorably with a much more complicated digital aided tracker. The parameter sensitivity reduction was treated by considering the variable parameters as random variables. A performance index is defined as a weighted sum of the state and control convariances that sum from both the random system disturbances and the parameter uncertainties, and is minimized numerically by adjusting a set of free parameters.

  6. The role of precise time in IFF

    NASA Technical Reports Server (NTRS)

    Bridge, W. M.

    1982-01-01

    The application of precise time to the identification of friend or foe (IFF) problem is discussed. The simple concept of knowing when to expect each signal is exploited in a variety of ways to achieve an IFF system which is hard to detect, minimally exploitable and difficult to jam. Precise clocks are the backbone of the concept and the various candidates for this role are discussed. The compact rubidium-controlled oscillator is the only practical candidate.

  7. Development of material irradiation rig with precision temperature control in experimental fast reactor JOYO

    NASA Astrophysics Data System (ADS)

    Kataoka, H.; Yasu, T.; Takatsudo, H.; Miyakawa, S.

    1998-10-01

    In the experimental fast reactor JOYO, an on-line instrumented material irradiation rig has been developed to acquire various irradiation data. Material Testing Rig with Temperature Control (MARICO) is capable of collecting creep rupture strength data for fast reactor fuel cladding materials. The specimen temperature in the MARICO-1 rig is controlled with an accuracy of ±4°C by the use of a gas gap method similar to that of FFTF/MOTA. Presently, irradiation testing using MARICO-1 has been so successful that the development of MARICO-2 is under way for completion by the early part of the next century. MARICO-2 will contain an electrical heater for temperature control, a larger irradiation space and other data collecting improvements.

  8. Amplitude Control of Solid-State Modulators for Precision Fast Kicker Applications

    SciTech Connect

    Watson, J A; Anaya, R M; Caporaso, G C; Chen, Y J; Cook, E G; Lee, B S; Hawkins, A

    2002-11-15

    A solid-state modulator with very fast rise and fall times, pulse width agility, and multi-pulse burst and intra-pulse amplitude adjustment capability for use with high speed electron beam kickers has been designed and tested at LLNL. The modulator uses multiple solid-state modules stacked in an inductive-adder configuration. Amplitude adjustment is provided by controlling individual modules in the adder, and is used to compensate for transverse e-beam motion as well as the dynamic response and beam-induced steering effects associated with the kicker structure. A control algorithm calculates a voltage based on measured e-beam displacement and adjusts the modulator to regulate beam centroid position. This paper presents design details of amplitude control along with measured performance data from kicker operation on the ETA-II accelerator at LLNL.

  9. Improvement of a geodetic triangulation through control points established by means of satellite or precision traversing

    NASA Technical Reports Server (NTRS)

    Saxena, N. K.

    1972-01-01

    Whether any significant increment to accuracy could be transferred from a super-control continental net (continental satellite net or super-transcontinental traverse) to the fundamental geodetic net (first-order triangulation) is discussed. This objective was accomplished by evaluating the positional accuracy improvement for a triangulation station, which is near the middle of the investigated geodetic triangulation net, by using various station constraints over its geodetic position. This investigation on a 1858 kilometer long triangulation chain shows that the super-control net can provide a useful constraint to the investigated geodetic triangulation net, and thus can improve it only when the accuracy of super-control net is at least 1 part in 500,000.

  10. Precision Position Control of Pneumatic Servo Table Embedded with Aerostatic Bearing

    NASA Astrophysics Data System (ADS)

    Tsai, Ming-Hung; Hsu, Tzu-Yung; Pai, Kei-Ren; Shih, Ming-Chang

    This paper treats the control of a pneumatic servo table combining the air cylinders and sliding guides embedded with aerostatic bearing. Since compressed air flows into the small gap between the bearing and the sliding guide, the cylinder floats around the air film and on the guide surface of the table. The friction forces of the pneumatic servo table are measured, and the relation of frictional force and speed is plotted. The hybrid self-tuning fuzzy controller with the velocity compensators and dead-zone are proposed in this paper. From the experimental results, in case of different position, the positioning accuracy can reach the 0.04μm.

  11. Establishing Causality Using Longitudinal Hierarchical Linear Modeling: An Illustration Predicting Achievement From Self-Control

    PubMed Central

    Duckworth, Angela Lee; Tsukayama, Eli; May, Henry

    2010-01-01

    The predictive validity of personality for important life outcomes is well established, but conventional longitudinal analyses cannot rule out the possibility that unmeasured third-variable confounds fully account for the observed relationships. Longitudinal hierarchical linear models (HLM) with time-varying covariates allow each subject to serve as his or her own control, thus eliminating between-individual confounds. HLM also allows the directionality of the causal relationship to be tested by reversing time-lagged predictor and outcome variables. We illustrate these techniques through a series of models that demonstrate that within-individual changes in self-control over time predict subsequent changes in GPA but not vice-versa. The evidence supporting a causal role for self-control was not moderated by IQ, gender, ethnicity, or income. Further analyses rule out one time-varying confound: self-esteem. The analytic approach taken in this study provides the strongest evidence to date for the causal role of self-control in determining achievement. PMID:20976121

  12. Controlling the Integration of Polyvinylpyrrolidone onto Substrate by Quartz Crystal Microbalance with Dissipation To Achieve Excellent Protein Resistance and Detoxification.

    PubMed

    Zheng, Jian; Wang, Lin; Zeng, Xiangze; Zheng, Xiaoyan; Zhang, Yan; Liu, Sa; Shi, Xuetao; Wang, Yingjun; Huang, Xuhui; Ren, Li

    2016-07-27

    Blood purification systems, in which the adsorbent removes exogenous and endogenous toxins from the blood, are widely used in clinical practice. To improve the protein resistance of and detoxification by the adsorbent, researchers can modify the adsorbent with functional molecules, such as polyvinylpyrrolidone (PVP). However, achieving precise control of the functional molecular density, which is crucial to the activity of the adsorbent, remains a significant challenge. In the present study, we prepared a model system for blood purification adsorbents in which we controlled the integration density of PVP molecules of different molecular weights on an Au substrate by quartz crystal microbalance with dissipation (QCM-D). We characterized the samples with atomic force microscopy, X-ray photoelectron spectroscopy, and QCM-D and found that the molecular density and the chain length of the PVP molecules played important roles in determining the properties of the sample. At the optimal condition, the modified sample demonstrated strong resistance to plasma proteins, decreasing the adsorption of human serum albumin (HSA) and fibrinogen (Fg) by 92.5% and 79.2%, respectively. In addition, the modified sample exhibited excellent detoxification, and the adsorption of bilirubin increased 2.6-fold. Interestingly, subsequent atomistic molecular dynamics simulations indicated that the favorable interactions between PVP and bilirubin were dominated by hydrophobic interactions. An in vitro platelet adhesion assay showed that the adhesion of platelets on the sample decreased and that the platelets were maintained in an inactivated state. The CCK-8 assay indicated that the modified sample exhibited negligible cytotoxicity to L929 cells. These results demonstrated that our method holds great potential for the modification of adsorbents in blood purification systems. PMID:27363467

  13. Precise control and animation creation over the DMD for projection-based applications

    NASA Astrophysics Data System (ADS)

    Koudsi, Badia

    2014-03-01

    Digital micromirror devices (DMDs) are used in a variety of display and projection applications to produce high resolution images, both static and animated. A common obstacle to working with DMDs in research and development applications is the steep learning curve required to obtain proficiency in programming the boards that control the behavior of the DMDs. This can discourage developers who wish to use DMDs in new or novel research and development applications which might benefit from their light-control properties. A new software package called Light Animator has been developed that provides a user friendly and more intuitive interface for controlling the DMD. The software allows users to address the micromirror array by the drawing and animation of objects in a style similar to that of commercial drawing programs. Sequences and animation are controlled by dividing the sequence into frames which the user can draw individually or the software can fill in for the user. Examples and descriptions of the software operation are described and operational performance measures are provided. Potential applications include 3D volumetric displays, a 3D scanner when combining the DMD with a CCD camera, and most any 2D application for which DMDs are currently used. The software's capabilities allow scientists to develop applications more easily and effectively.

  14. The Contributions of Onchocerciasis Control and Elimination Programs toward the Achievement of the Millennium Development Goals

    PubMed Central

    Dunn, Caitlin; Callahan, Kelly; Katabarwa, Moses; Richards, Frank; Hopkins, Donald; Withers, P. Craig; Buyon, Lucas E.; McFarland, Deborah

    2015-01-01

    In 2000, 189 member states of the United Nations (UN) developed a plan for peace and development, which resulted in eight actionable goals known as the Millennium Development Goals (MDGs). Since their inception, the MDGs have been considered the international standard for measuring development progress and have provided a blueprint for global health policy and programming. However, emphasis upon the achievement of priority benchmarks around the “big three” diseases—namely HIV, tuberculosis (TB), and malaria—has influenced global health entities to disproportionately allocate resources. Meanwhile, several tropical diseases that almost exclusively impact the poorest of the poor continue to be neglected, despite the existence of cost-effective and feasible methods of control or elimination. One such Neglected Tropical Disease (NTD), onchocerciasis, more commonly known as river blindness, is a debilitating and stigmatizing disease primarily affecting individuals living in remote and impoverished areas. Onchocerciasis control is considered to be one of the most successful and cost-effective public health campaigns ever launched. In addition to improving the health and well-being of millions of individuals, these programs also lead to improvements in education, agricultural production, and economic development in affected communities. Perhaps most pertinent to the global health community, though, is the demonstrated effectiveness of facilitating community engagement by allowing communities considerable ownership with regard to drug delivery. This paper reviews the contributions that such concentrated efforts to control and eliminate onchocerciasis make to achieving select MDGs. The authors hope to draw the attention of public policymakers and global health funders to the importance of the struggle against onchocerciasis as a model for community-directed interventions to advance health and development, and to advocate for NTDs inclusion in the post 2015 agenda

  15. The Contributions of Onchocerciasis Control and Elimination Programs toward the Achievement of the Millennium Development Goals.

    PubMed

    Dunn, Caitlin; Callahan, Kelly; Katabarwa, Moses; Richards, Frank; Hopkins, Donald; Withers, P Craig; Buyon, Lucas E; McFarland, Deborah

    2015-05-01

    In 2000, 189 member states of the United Nations (UN) developed a plan for peace and development, which resulted in eight actionable goals known as the Millennium Development Goals (MDGs). Since their inception, the MDGs have been considered the international standard for measuring development progress and have provided a blueprint for global health policy and programming. However, emphasis upon the achievement of priority benchmarks around the "big three" diseases--namely HIV, tuberculosis (TB), and malaria--has influenced global health entities to disproportionately allocate resources. Meanwhile, several tropical diseases that almost exclusively impact the poorest of the poor continue to be neglected, despite the existence of cost-effective and feasible methods of control or elimination. One such Neglected Tropical Disease (NTD), onchocerciasis, more commonly known as river blindness, is a debilitating and stigmatizing disease primarily affecting individuals living in remote and impoverished areas. Onchocerciasis control is considered to be one of the most successful and cost-effective public health campaigns ever launched. In addition to improving the health and well-being of millions of individuals, these programs also lead to improvements in education, agricultural production, and economic development in affected communities. Perhaps most pertinent to the global health community, though, is the demonstrated effectiveness of facilitating community engagement by allowing communities considerable ownership with regard to drug delivery. This paper reviews the contributions that such concentrated efforts to control and eliminate onchocerciasis make to achieving select MDGs. The authors hope to draw the attention of public policymakers and global health funders to the importance of the struggle against onchocerciasis as a model for community-directed interventions to advance health and development, and to advocate for NTDs inclusion in the post 2015 agenda. PMID

  16. A non-destructive n-doping method for graphene with precise control of electronic properties via atomic layer deposition.

    PubMed

    Han, Kyu Seok; Kalode, Pranav Y; Koo Lee, Yong-Eun; Kim, Hongbum; Lee, Lynn; Sung, Myung Mo

    2016-02-25

    Graphene applications require high precision control of the Fermi level and carrier concentration via a nondestructive doping method. Here, we develop an effective n-doping technique using atomic layer deposition (ALD) of ZnO thin films on graphene through a reactive molecular layer. This ALD doping method is nondestructive, simple, and precise. The ZnO thin films on graphene are uniform, conformal, of good quality with a low density of pinholes, and finely tunable in thickness with 1 Å resolution. We demonstrate graphene transistor control in terms of the Dirac point, carrier density, and doping state as a function of the ZnO thickness. Moreover, ZnO functions as an effective thin-film barrier against air-borne water and oxygen on the graphene, resulting in extraordinary stability in air for graphene devices. ZnO ALD was also applied to other two-dimensional materials including MoS2 and WSe2, which substantially enhanced electron mobility. PMID:26864992

  17. Two-stage case-control studies: precision of parameter estimates and considerations in selecting sample size.

    PubMed

    Hanley, James A; Csizmadi, Ilona; Collet, Jean-Paul

    2005-12-15

    A two-stage case-control design, in which exposure and outcome are determined for a large sample but covariates are measured on only a subsample, may be much less expensive than a one-stage design of comparable power. However, the methods available to plan the sizes of the stage 1 and stage 2 samples, or to project the precision/power provided by a given configuration, are limited to the case of a binary exposure and a single binary confounder. The authors propose a rearrangement of the components in the variance of the estimator of the log-odds ratio. This formulation makes it possible to plan sample sizes/precision by including variance inflation factors to deal with several confounding factors. A practical variance bound is derived for two-stage case-control studies, where confounding variables are binary, while an empirical investigation is used to anticipate the additional sample size requirements when these variables are quantitative. Two methods are suggested for sample size planning based on a quantitative, rather than binary, exposure. PMID:16269581

  18. An influence of the stepping motor control and friction models on precise positioning of the complex mechanical system

    NASA Astrophysics Data System (ADS)

    Konowrocki, Robert; Szolc, Tomasz; Pochanke, Andrzej; Pręgowska, Agnieszka

    2016-03-01

    This paper aims to investigate, both experimentally and theoretically, the electromechanical dynamic interaction between a driving stepping motor and a driven laboratory belt-transporter system. A test-rig imitates the operation of a robotic device in the form of a working tool-carrier under translational motion. The object under consideration is equipped with measurement systems, which enable the registration of electrical and mechanical quantities. Analytical considerations are performed by means of a circuit model of the electric motor and a discrete, non-linear model of the mechanical system. Various scenarios of the working tool-carrier motion and positioning by the belt-transporter are measured and simulated; in all cases the electric current control of the driving motor has been applied. The main goal of this study is to investigate the influence of the stepping motor control parameters along with various mechanical friction models on the precise positioning of a laboratory robotic device.

  19. Engineering light-inducible nuclear localization signals for precise spatiotemporal control of protein dynamics in living cells

    PubMed Central

    Niopek, Dominik; Benzinger, Dirk; Roensch, Julia; Draebing, Thomas; Wehler, Pierre; Eils, Roland; Di Ventura, Barbara

    2014-01-01

    The function of many eukaryotic proteins is regulated by highly dynamic changes in their nucleocytoplasmic distribution. The ability to precisely and reversibly control nuclear translocation would, therefore, allow dissecting and engineering cellular networks. Here we develop a genetically encoded, light-inducible nuclear localization signal (LINuS) based on the LOV2 domain of Avena sativa phototropin 1. LINuS is a small, versatile tag, customizable for different proteins and cell types. LINuS-mediated nuclear import is fast and reversible, and can be tuned at different levels, for instance, by introducing mutations that alter AsLOV2 domain photo-caging properties or by selecting nuclear localization signals (NLSs) of various strengths. We demonstrate the utility of LINuS in mammalian cells by controlling gene expression and entry into mitosis with blue light. PMID:25019686

  20. Longitudinal relations among parents' reactions to children's negative emotions, effortful control, and math achievement in early elementary school.

    PubMed

    Swanson, Jodi; Valiente, Carlos; Lemery-Chalfant, Kathryn; Bradley, Robert H; Eggum-Wilkens, Natalie D

    2014-01-01

    Panel mediation models and fixed-effects models were used to explore longitudinal relations among parents' reactions to children's displays of negative emotions, children's effortful control (EC), and children's math achievement (N = 291; M age in fall of kindergarten = 5.66 years, SD = .39 year) across kindergarten through second grade. Parents reported their reactions and children's EC. Math achievement was assessed with a standardized achievement test. First-grade EC mediated the relation between parents' reactions at kindergarten and second-grade math achievement, beyond stability in constructs across study years. Panel mediation model results suggested that socialization of EC may be one method of promoting math achievement in early school; however, when all omitted time-invariant covariates of EC and math achievement were controlled, first-grade EC no longer predicted second-grade math achievement. PMID:24916765

  1. Comparing the Precision of Information Retrieval of MeSH-Controlled Vocabulary Search Method and a Visual Method in the Medline Medical Database

    PubMed Central

    Hariri, Nadjla; Ravandi, Somayyeh Nadi

    2014-01-01

    Background: Medline is one of the most important databases in the biomedical field. One of the most important hosts for Medline is Elton B. Stephens CO. (EBSCO), which has presented different search methods that can be used based on the needs of the users. Visual search and MeSH-controlled search methods are among the most common methods. The goal of this research was to compare the precision of the retrieved sources in the EBSCO Medline base using MeSH-controlled and visual search methods. Methods: This research was a semi-empirical study. By holding training workshops, 70 students of higher education in different educational departments of Kashan University of Medical Sciences were taught MeSH-Controlled and visual search methods in 2012. Then, the precision of 300 searches made by these students was calculated based on Best Precision, Useful Precision, and Objective Precision formulas and analyzed in SPSS software using the independent sample T Test, and three precisions obtained with the three precision formulas were studied for the two search methods. Results: The mean precision of the visual method was greater than that of the MeSH-Controlled search for all three types of precision, i.e. Best Precision, Useful Precision, and Objective Precision, and their mean precisions were significantly different (P <0.001). Sixty-five percent of the researchers indicated that, although the visual method was better than the controlled method, the control of keywords in the controlled method resulted in finding more proper keywords for the searches. Fifty-three percent of the participants in the research also mentioned that the use of the combination of the two methods produced better results. Conclusion: For users, it is more appropriate to use a natural, language-based method, such as the visual method, in the EBSCO Medline host than to use the controlled method, which requires users to use special keywords. The potential reason for their preference was that the visual

  2. Precise control of interface anisotropy during deposition of Co/Pd multilayers

    SciTech Connect

    Barton, C. W. Thomson, T.; Slater, T. J. A.; Haigh, S. J.; Rowan-Robinson, R. M.; Atkinson, D.

    2014-11-28

    We demonstrate the control of perpendicular magnetic anisotropy (PMA) in multilayer films without modification of either the microstructure or saturation magnetization by tuning the Ar{sup +} ion energy using remote plasma sputtering. We show that for [Co/Pd]{sub 8} multilayer films, increasing the Ar{sup +} ion energy results in a strong decrease in PMA through an increase in interfacial roughness determined by X-ray reflectivity measurements. X-ray diffraction and transmission electron microscope image data show that the microstructure is independent of Ar{sup +} energy. This opens a different approach to the in-situ deposition of graded exchange springs and for control of the polarizing layer in hybrid spin transfer torque devices.

  3. Precision stacking of nanoparticle laden sessile droplets to control solute deposit morphology

    NASA Astrophysics Data System (ADS)

    Kabi, Prasenjit; Basu, Saptarshi; Sanyal, Apratim; Chaudhuri, Swetaprovo

    2015-02-01

    Stacking pure solvent droplets on a solid substrate is apparently impossible in the absence of an external force as the second droplet will invariably spill over the first leading to a large wetted area. However, the unique feature that emerges during the drying of a nanoparticle laden droplet is the progressively enlarging thin solid film along the evaporating sessile droplet liquid periphery. This solid interface: the edge of which we shall refer to as the agglomeration front comprises of a thin layer of nanoparticle assembly and can support a carefully dispensed second droplet thereby allowing droplet stacking. It will be shown that the growth of this agglomeration front can also be effectively controlled by the dispensing time difference and the nanoparticle concentration in the two droplets. So far, we are commonly aware of material stacking in solid phase. This letter demonstrates stacking in the liquid phase and control over the thin solid interface growth.

  4. Precise thermal control test demonstration on simulated space telescope main ring

    NASA Technical Reports Server (NTRS)

    Bettini, R. G.; Wegrich, R. D.

    1983-01-01

    A simulated section of the main ring of the Space Telescope, (ST) the part that holds the primary mirror, was manufactured and tested for thermal stability characteristics in a complex structural assembly. The other telescope subassemblies are also mounted on the main ring, which is constructed of a titanium alloy. The entire ring is wrapped in heater elements around the outside diameter to reduce the external temperature gradient effects by two orders of magnitude. A thermal vacuum test was performed using a stainless steel alloy tailored to represent the titanium ring's thermal characteristics. The tests examined the thermal performance and controllability of the test ring, the effects of a 24-hr slew manuever that produced worst-case environment changes, hot and cold simulation of predicted ST orbital thermal environments, and the effects of heater failure. Pointing and thermal control features were verified, but a heater failure on the 'on' side was found to quickly lead to exceeding the thermal design limits.

  5. An automatic pellet dispenser for precise control of feeding topography in granivorous birds

    PubMed Central

    Berkhoudt, H.; Van Der Reijden, D.; Heijmans, M.

    1987-01-01

    Design and construction of an automatic pellet dispenser for granivorous birds are described. The dispenser permits rapid pneumatic delivery of pellets (five pellets per second maximum) to one controlled position and does not interfere with simultaneous electrophysiological recording. In addition, the device continuously indicates presence or absence of a pellet in the delivery position. This automatic dispenser proved very effective in our studies of stereotyped topographies of feeding in granivorous birds, such as pigeons and chickens. PMID:16812503

  6. ST7-DRS: A Step Towards Drag-free and High-precision Formation Control

    NASA Technical Reports Server (NTRS)

    Houghton, M.; Folkner, W.; Hanson, J.; Hruby, V.

    2003-01-01

    The Space Technology 7 Disturbance Reduction System (ST7-DRS) is an in-space technology demonstration within NASA's New Millennium Program. ST7-DRS is designed to validate system-level technologies that are required for future gravity missions (including the planned LISA gravitational-wave observatory) and for future formation-flying interferometer missions (including the planned MAXIM black-hole imager). ST7-DRS is based around a freely-floating test mass contained within a spacecraft structure that will shield this test mass from all external forces (aside from gravity). The spacecraft position will be continuously controlled, such that the spacecraft, itself, will remain centered about this test mass, essentially flying in formation with it. Colloidal micro-thrusters will be used to control the spacecraft s position to within a few nanometers, over time scales of tens to thousands of seconds. In order to detect the residual acceleration noise on the main test mass, a second test mass will be flown alongside the first, within the same physical spacecraft structure. This test mass will serve as a cross-reference for the first, and will also be used as a reference for the spacecraft's attitude control. The spacecraft's attitude will be controlled to an accuracy of a few milli-arc-seconds, also utilizing the colloidal micro-thrusters. ST7-DRS will consist of an instrument package (containing the test masses) and a set of micro-thrusters, which will be attached to the European Space Agency s SMART-2 spacecraft, set to launch in November 2007.

  7. Achieving Energy Savings with Highly-Controlled Lighting in an Open-Plan Office

    SciTech Connect

    Rubinstein, Francis; Enscoe, Abby

    2010-04-19

    An installation in a Federal building tested the effectiveness of a highly-controlled, workstation-specific lighting retrofit. The study took place in an open-office area with 86 cubicles and low levels of daylight. Each cubicle was illuminated by a direct/indirectpendant luminaire with three 32 watt lamps, two dimmable DALI ballasts, and an occupancy sensor. A centralized control system programmed all three lamps to turn on and off according to occupancy on a workstation-by-workstation basis. Field measurements taken over the course of several monthsdemonstrated 40% lighting energy savings compared to a baseline without advanced controls that conforms to GSA's current retrofit standard. A photometric analysis found that the installation provided higher desktop light levels than the baseline, while an occupant survey found that occupants in general preferred the lighting system to thebaseline.Simple payback is fairly high; projects that can achieve lower installation costs and/or higher energy savings and those in which greenhouse gas reduction and occupant satisfaction are significant priorities provide the ideal setting for workstation-specific lighting retrofits.

  8. Automatic control system of high precision welding of workpieces in mechanical engineering

    NASA Astrophysics Data System (ADS)

    Kuznetsov, I. N.; Zvezdin, V. V.; Israfilov, I. H.; Portnov, S. M.

    2014-12-01

    In this paper, based on the conducted patent research, the system of laser welding control with different geometry of weld and shapes of parts is developed. The method of monitoring the position of the spot of laser radiation in relation to the curved weld is worked out; it is based on the tracking the edges of the welded parts by low-power laser radiation reflected from the surface of the parts. It allows to make the positioning of the focus of laser radiation in relation to the juncture of the welded parts automatically.

  9. Analysis, testing, and control of telescope's high-precision drive system in low-temperature environment

    NASA Astrophysics Data System (ADS)

    Du, Fu-Jia; Zhang, Jian; Wen, Hai-Kun

    2014-07-01

    Antarctic is perfect site for astronomic observatory. But Antarctic also challenge the telescope design because of low temperature. The low temperature can impact characterization of telescope control system, especially for drive system. The following phenomenon can be produced due to low temperature. 1. The viscosity of grease will increase. 2. The clearance of bearing and gear will decrease. These two factors can lead to the increase in load torque of drive system with temperature drop. This would cause the bad tracking accuracy and low speed creeping. In order to overcome the impact of low temperature and improve the telescope's track accuracy. In this paper, we describe some methods to overcome the effect of low temperature. First, the motor's electromagnetism and lubrication in low temperature are analyzed. It shows that motor's electromagnetism is little affected by temperature if the suitable material is selected. But the characterization of grease change dramatically with temperature. Second, the other lubricant material, solid lubricant, instead of lubricating grease is proposed. Contrasting experiment on two lubricant material proved that the solid lubricant is better than lubricating grease in low temperature environment. Third, besides the mechanical solution, a method from control point view is proposed to reduce the temperature influence. In this paper, the friction feedforward algorithm is used to compensate the torque change. Laboratory testing results will be presented verifying that friction feedforward can increase the tracking accuracy in low temperature environment.

  10. Pollution control system design for achieving stringent emissions standards on waste incineration facilities -- a case study

    SciTech Connect

    Weaver, E.H.; Bourgoin, S.

    1998-12-31

    In Germany, environmental standards for non-municipal waste incineration are set to not only achieve very low emissions to the atmosphere, but to also ensure that the solid residues generated are of acceptable quality for final disposal and that no liquid effluent is discharged from the system. In order to control pollution from these facilities, an integrated system is required to address the air, liquid and solid regulatory issues. This paper examines one recent facility installed in Germany which incorporates all of the design features required to comply with those standards. The facility examined is an industrial waste incineration facility located at an oil refinery in northeastern Germany. Equipped with a spray dryer absorber, fabric filter, and wet scrubber, the system is designed to achieve HCl emissions of less than 10 mg/Nm{sup 3} and SO{sub 2} emissions of less than 50 mg/Nm{sup 3}. Particulate emissions must be below 10 mg/Nm{sup 3}. The limit for mercury emissions is 50 ug/Nm{sup 3}, while dioxin emissions must be below 0.10 ng/Nm{sup 3}. Purge water from the wet scrubbing system containing salts is dried in the spray dryer absorber and collected as a dry waste in the fabric filter following the spray dryer absorber. The detailed design of the pollution control system is discussed, along with considerations to ensure continuous compliance with allowable emission levels. Operation of the facility is discussed, along with special operating issues that have been encountered since startup. Finally, performance tests and emissions data are presented to illustrate the actual performance level of the facility.

  11. Artificial Pancreas Using a Personalized Rule-Based Controller Achieves Overnight Normoglycemia in Patients with Type 1 Diabetes

    PubMed Central

    Rigla, Mercedes; García-Sáez, Gema; Rodríguez-Herrero, Agustín; Pons, Belén; Subías, David; García-García, Fernando; Gallach, Maria; Aguilar, Montserrat; Pérez-Gandía, Carmen; Gómez, Enrique J.; Caixàs, Assumpta; Hernando, M. Elena

    2014-01-01

    Abstract Objective: This study assessed the efficacy of a closed-loop (CL) system consisting of a predictive rule-based algorithm (pRBA) on achieving nocturnal and postprandial normoglycemia in patients with type 1 diabetes mellitus (T1DM). The algorithm is personalized for each patient's data using two different strategies to control nocturnal and postprandial periods. Research Design and Methods: We performed a randomized crossover clinical study in which 10 T1DM patients treated with continuous subcutaneous insulin infusion (CSII) spent two nonconsecutive nights in the research facility: one with their usual CSII pattern (open-loop [OL]) and one controlled by the pRBA (CL). The CL period lasted from 10 p.m. to 10 a.m., including overnight control, and control of breakfast. Venous samples for blood glucose (BG) measurement were collected every 20 min. Results: Time spent in normoglycemia (BG, 3.9–8.0 mmol/L) during the nocturnal period (12 a.m.–8 a.m.), expressed as median (interquartile range), increased from 66.6% (8.3–75%) with OL to 95.8% (73–100%) using the CL algorithm (P<0.05). Median time in hypoglycemia (BG, <3.9 mmol/L) was reduced from 4.2% (0–21%) in the OL night to 0.0% (0.0–0.0%) in the CL night (P<0.05). Nine hypoglycemic events (<3.9 mmol/L) were recorded with OL compared with one using CL. The postprandial glycemic excursion was not lower when the CL system was used in comparison with conventional preprandial bolus: time in target (3.9–10.0 mmol/L) 58.3% (29.1–87.5%) versus 50.0% (50–100%). Conclusions: A highly precise personalized pRBA obtains nocturnal normoglycemia, without significant hypoglycemia, in T1DM patients. There appears to be no clear benefit of CL over prandial bolus on the postprandial glycemia. PMID:24152323

  12. Precision vector control of a superconducting RF cavity driven by an injection locked magnetron

    DOE PAGESBeta

    Chase, Brian; Pasquinelli, Ralph; Cullerton, Ed; Varghese, Philip

    2015-03-01

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons [1]. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs - compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRFmore » cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.« less

  13. Precision vector control of a superconducting RF cavity driven by an injection locked magnetron

    SciTech Connect

    Chase, Brian; Pasquinelli, Ralph; Cullerton, Ed; Varghese, Philip

    2015-03-01

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons [1]. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs - compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.

  14. Precise Control of the Number of Layers of Graphene by Picosecond Laser Thinning

    PubMed Central

    Lin, Zhe; Ye, Xiaohui; Han, Jinpeng; Chen, Qiao; Fan, Peixun; Zhang, Hongjun; Xie, Dan; Zhu, Hongwei; Zhong, Minlin

    2015-01-01

    The properties of graphene can vary as a function of the number of layers (NOL). Controlling the NOL in large area graphene is still challenging. In this work, we demonstrate a picosecond (ps) laser thinning removal of graphene layers from multi-layered graphene to obtain desired NOL when appropriate pulse threshold energy is adopted. The thinning process is conducted in atmosphere without any coating and it is applicable for graphene films on arbitrary substrates. This method provides many advantages such as one-step process, non-contact operation, substrate and environment-friendly, and patternable, which will enable its potential applications in the manufacturing of graphene-based electronic devices. PMID:26111758

  15. Precise and millidegree stable temperature control for fluorescence imaging: Application to phase transitions in lipid membranes

    PubMed Central

    Farkas, Elaine R.; Webb, Watt W.

    2010-01-01

    We present the design of a custom temperature-controlled chamber suitable for water or oil immersion fluorescence microscopy and its application to phase behavior in lipid bilayer vesicles. The apparatus is self-contained and portable, suitable for multiuser microscopy facilities. It offers a higher temperature resolution and stability than any comparable commercial apparatus, on the order of millidegrees. We demonstrate the utility of the system in the study of miscibility transitions in model membranes. The temperature-dependent phase behavior of model membrane systems that display liquid-ordered (Lo) phase coexistence with the liquid-disordered (Ld) phase is relevant to understanding the existence of heterogeneities in biological cell plasma membranes, ubiquitously termed “lipid rafts.” PMID:20886984

  16. The Target Achievement Control Test: Evaluating real-time myoelectric pattern recognition control of a multifunctional upper-limb prosthesis

    PubMed Central

    Simon, Ann M.; Hargrove, Levi J.; Lock, Blair A.; Kuiken, Todd A.

    2014-01-01

    Despite high classification accuracies (~95%) of myoelectric control systems based on pattern recognition, it is unclear how well offline measures translate to real-time closed-loop control. Recently, a real-time virtual test analyzed how well subjects completed motions using a multiple–degree of freedom (DOF) classifier. Although this test provided real-time performance metrics, the required task was oversimplified: motion speeds were normalized and unintended movements were ignored. We included these considerations in a new, more challenging virtual test, the Target Achievement Control (TAC) Test. Users attempted to move a virtual arm into a target posture using myoelectric pattern recognition. Five transradial amputees performed the test with various classifier (one vs. three DOF) and task complexities (one vs. three required motions per posture). No significant difference was found in classification accuracy between the one- and three- DOF classifiers (97.2%±2.0% and 94.1%±3.1%, respectively) (p=0.14). Subjects completed 31% fewer trials in significantly more time using the three-DOF classifier. Subjects took 3.6±0.8 times longer to reach a three-motion posture compared to a one-motion posture. The results highlight the need for closed-loop performance measures and demonstrate that the TAC Test provides a useful and more challenging tool to test real-time pattern recognition performance. PMID:21938650

  17. Methods for building an inexpensive computer-controlled olfactometer for temporally precise experiments

    PubMed Central

    Lundström, Johan N.; Gordon, Amy R.; Alden, Eva C.; Boesveldt, Sanne; Albrecht, Jessica

    2010-01-01

    Many human olfactory experiments call for fast and stable stimulus-rise times as well as exact and stable stimulus-onset times. Due to these temporal demands, an olfactometer is often needed. However, an olfactometer is a piece of equipment that either comes with a high price tag or requires a high degree of technical expertise to build and/or to run. Here, we detail the construction of an olfactometer that is constructed almost exclusively with “off-the-shelf” parts, requires little technical knowledge to build, has relatively low price tags, and is controlled by E-Prime, a turnkey-ready and easily-programmable software commonly used in psychological experiments. The olfactometer can present either solid or liquid odor sources, and it exhibits a fast stimulus-rise time and a fast and stable stimulus-onset time. We provide a detailed description of the olfactometer construction, a list of its individual parts and prices, as well as potential modifications to the design. In addition, we present odor onset and concentration curves as measured with a photoionization detector, together with corresponding GC/MS analyses of signal-intensity drop (5.9%) over a longer period of use. Finally, we present data from behavioral and psychophysiological recordings demonstrating that the olfactometer is suitable for use during event-related EEG experiments. PMID:20688109

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  19. Precision control of carrier-envelope phase in grating based chirped pulse amplifiers.

    PubMed

    Li, Chengquan; Moon, Eric; Mashiko, Hiroki; Nakamura, Christopher M; Ranitovic, Predrag; Maharjan, Chakra M; Cocke, C Lewis; Chang, Zenghu; Paulus, Gerhard G

    2006-11-13

    It is demonstrated that the carrier-envelope (CE) phase of pulses from a high power ultrafast laser system with a grating-based stretcher and compressor can be stabilized to a root mean square (rms) value of 180 mrad over almost 2 hours, excluding a brief re-locking period. The stabilization was accomplished via feedback control of the grating separation in the stretcher. It shows that the long term CE phase stability of a grating based chirped pulse amplification system can be as good as that of lasers using a glass-block stretcher and a prism pair compressor. Moreover, by adjusting the grating separation to preset values, the relative CE phase could be locked to an arbitrary value in the range of 2pi. This method is better than using a pair of wedge plates to adjust the phase after the hollow-core fiber compressor. The CE phase stabilization after a hollow-core fiber compressor was confirmed by a CE-phase meter based on the measurement of the left-to-right asymmetry of electrons produced by above-threshold ionization. PMID:19529565

  20. Electromagnetic Controlled Cortical Impact Device for Precise, Graded Experimental Traumatic Brain Injury

    PubMed Central

    BRODY, DAVID L.; DONALD, CHRISTINE Mac; KESSENS, CHAD C.; YUEDE, CARLA; PARSADANIAN, MAIA; SPINNER, MIKE; KIM, EDDIE; SCHWETYE, KATHERINE E.; HOLTZMAN, DAVID M.; BAYLY, PHILIP V.

    2008-01-01

    Genetically modified mice represent useful tools for traumatic brain injury (TBI) research and attractive preclinical models for the development of novel therapeutics. Experimental methods that minimize the number of mice needed may increase the pace of discovery. With this in mind, we developed and characterized a prototype electromagnetic (EM) controlled cortical impact device along with refined surgical and behavioral testing techniques. By varying the depth of impact between 1.0 and 3.0 mm, we found that the EM device was capable of producing a broad range of injury severities. Histologically, 2.0-mm impact depth injuries produced by the EM device were similar to 1.0-mm impact depth injuries produced by a commercially available pneumatic device. Behaviorally, 2.0-, 2.5-, and 3.0-mm impacts impaired hidden platform and probe trial water maze performance, whereas 1.5-mm impacts did not. Rotorod and visible platform water maze deficits were also found following 2.5- and 3.0-mm impacts. No impairment of conditioned fear performance was detected. No differences were found between sexes of mice. Inter-operator reliability was very good. Behaviorally, we found that we could statistically distinguish between injury depths differing by 0.5 mm using 12 mice per group and between injury depths differing by 1.0 mm with 7-8 mice per group. Thus, the EM impactor and refined surgical and behavioral testing techniques may offer a reliable and convenient framework for preclinical TBI research involving mice. PMID:17439349

  1. Design and control of one precise tracking simulation bed for Chinese 20/30 meter optic/infrared telescope

    NASA Astrophysics Data System (ADS)

    Ren, Changzhi; Li, Xiaoyan; Song, Xiaoli; Niu, Yong; Li, Aihua; Zhang, Zhenchao

    2012-09-01

    Direct drive technology is the key to solute future 30-m and larger telescope motion system to guarantee a very high tracking accuracy, in spite of unbalanced and sudden loads such as wind gusts and in spite of a structure that, because of its size, can not be infinitely stiff. However, this requires the design and realization of unusually large torque motor that the torque slew rate must be extremely steep too. A conventional torque motor design appears inadequate. This paper explores one redundant unit permanent magnet synchronous motor and its simulation bed for 30-m class telescope. Because its drive system is one high integrated electromechanical system, one complexly electromechanical design method is adopted to improve the efficiency, reliability and quality of the system during the design and manufacture circle. This paper discusses the design and control of the precise tracking simulation bed in detail.

  2. Controlling precise magnetic field configuration around electron cyclotron resonance zone for enhancing plasma parameters and beam current

    SciTech Connect

    Yano, Keisuke Kurisu, Yosuke; Nozaki, Dai; Kimura, Daiju; Imai, Youta; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-15

    Multi-charged ion source which has wide operating conditions is required in various application fields. We have constructed tandem type ECR ion source (ECRIS); one of the features of its main stage is an additional coil for controlling magnetic field distribution around the mirror bottom precisely. Here the effect of magnetic field variation caused by the additional coil is experimentally considered in terms of plasma parameters and beam current as the first investigation of the main stage plasma. Furthermore, behavior of magnetic lines of force flowing from the ECR zone is calculated, and is compared with measurement results aiming for better understanding of interrelationship between plasma production and ion beam generation on the ECRIS.

  3. The Relationship of Locus of Control and Self-Efficacy to Academic Achievement of First-Year Students

    ERIC Educational Resources Information Center

    Hoover, Kathleen Geiger

    2003-01-01

    This correlation study assessed whether the psychological variables of college students' locus of control, self-efficacy, and achievement expectations strengthen the prediction of academic achievement beyond that of traditional cognitive measures of high school grade point average and scores on the ACT or SAT examination. The study used earned…

  4. Plasma microcontact patterning (PμCP): a technique for the precise control of surface patterning at small-scale.

    PubMed

    Picone, Remigio; Baum, Buzz; McKendry, Rachel

    2014-01-01

    Plasma microcontact patterning (PμCP) is a simple, efficient, and cost-effective method for the precise patterning of molecules on surfaces. It combines the use of low-pressure plasma with an elastomeric 3D mask to spatially control the removal of molecules, such as proteins, from a surface. The entire PμCP process is subdivided into three main steps: surface precoating, plasma micropatterning, and a surface postcoating step. Surfaces are first precoated with a molecular species and then placed in close contact with the 3D mask. This allows the formation of two distinct regions: an un-masked open-region which is accessible to the plasma, from which the surface layer is removed, and, a contact region which is physically protected from exposure to the plasma. In the final step, a second molecule is added to back-fill the pattern generated through plasma-treatment. The PμCP technique allows the patterning of virtually any organic molecules on different surface materials and geometries (e.g., flat, curved surfaces, and 3D microstructures). Moreover, it is a simple and robust procedure. The main advantages of this approach over traditional microcontact printing are twofold: The stability of molecule binding to plasma-treated surfaces, and the separation of the surface functionalization step from the actual micropatterning step, which enables the precise control of concentration and uniformity of patterned molecules. In conclusion, PμCP is a simple way to generate surface patterns that are highly reproducible, stable and uniform, making it a useful method for many applications. PMID:24439280

  5. Boredom in Achievement Settings: Exploring Control-Value Antecedents and Performance Outcomes of a Neglected Emotion

    ERIC Educational Resources Information Center

    Pekrun, Reinhard; Goetz, Thomas; Daniels, Lia M.; Stupnisky, Robert H.; Perry, Raymond P.

    2010-01-01

    The linkages of achievement-related boredom with students' appraisals and performance outcomes were examined in a series of 5 exploratory, cross-sectional, and predictive investigations. Studies 1 and 2 assessed students' boredom in a single achievement episode (i.e., state achievement boredom); Studies 3, 4, and 5 focused on their habitual…

  6. A probability model for evaluating the bias and precision of influenza vaccine effectiveness estimates from case-control studies.

    PubMed

    Haber, M; An, Q; Foppa, I M; Shay, D K; Ferdinands, J M; Orenstein, W A

    2015-05-01

    As influenza vaccination is now widely recommended, randomized clinical trials are no longer ethical in many populations. Therefore, observational studies on patients seeking medical care for acute respiratory illnesses (ARIs) are a popular option for estimating influenza vaccine effectiveness (VE). We developed a probability model for evaluating and comparing bias and precision of estimates of VE against symptomatic influenza from two commonly used case-control study designs: the test-negative design and the traditional case-control design. We show that when vaccination does not affect the probability of developing non-influenza ARI then VE estimates from test-negative design studies are unbiased even if vaccinees and non-vaccinees have different probabilities of seeking medical care against ARI, as long as the ratio of these probabilities is the same for illnesses resulting from influenza and non-influenza infections. Our numerical results suggest that in general, estimates from the test-negative design have smaller bias compared to estimates from the traditional case-control design as long as the probability of non-influenza ARI is similar among vaccinated and unvaccinated individuals. We did not find consistent differences between the standard errors of the estimates from the two study designs. PMID:25147970

  7. Development and Clinical Application of a Precise Temperature-Control Device as an Alternate for Conventional Moxibustion Therapy

    PubMed Central

    Takayama, Shin; Takashima, Shigeru; Okajima, Junnosuke; Watanabe, Masashi; Kamiya, Tetsuharu; Seki, Takashi; Yamasaki, Miyako; Yaegashi, Nobuo; Yambe, Tomoyuki; Maruyama, Shigenao

    2012-01-01

    Moxibustion therapy has been used in East Asian medicine for more than a thousand years. However, there are some problems associated with this therapy in clinical practice. These problems include lack of control over the treatment temperature, emission of smoke, and uneven temperature distribution over the treatment region. In order to resolve these problems, we developed a precise temperature-control device for use as an alternate for conventional moxibustion therapy. In this paper, we describe the treatment of a single patient with paralytic ileus that was treated with moxibustion. We also describe an evaluation of temperature distribution on the skin surface after moxibustion therapy, the development of a heat-transfer control device (HTCD), an evaluation of the HTCD, and the clinical effects of treatment using the HTCD. The HTCD we developed can heat the skin of the treatment region uniformly, and its effect may be equivalent to conventional moxibustion, without the emission of smoke and smell. This device can be used to treat ileus, abdominal pain, and coldness of abdomen in place of conventional moxibustion in modern hospitals. PMID:22754583

  8. Precision control of an invasive ant on an ecologically sensitive tropical island: a principle with wide applicability.

    PubMed

    Gaigher, R; Samways, M J; Jolliffe, K G; Jolliffe, S

    2012-07-01

    Effective management of invasive ants is an important priority for many conservation programs but can be difficult to achieve, especially within ecologically sensitive habitats. This study assesses the efficacy and nontarget risk of a precision ant baiting method aiming to reduce a population of the invasive big-headed ant Pheidole megacephala on a tropical island of great conservation value. Area-wide application of a formicidal bait, delivered in bait stations, resulted in the rapid decline of 8 ha of P. megacephala. Effective suppression remained throughout the succeeding 11-month monitoring period. We detected no negative effects of baiting on nontarget arthropods. Indeed, species richness of nontarget ants and abundance of other soil-surface arthropods increased significantly after P. megacephala suppression. This bait station method minimized bait exposure to nontarget organisms and was cost effective and adaptable to target species density. However, it was only effective over short distances and required thorough bait placement. This method would therefore be most appropriate for localized P. megacephala infestations where the prevention of nontarget impacts is essential. The methodology used here would be applicable to other sensitive tropical environments. PMID:22908700

  9. Achieving a new controllable male contraception by the photothermal effect of gold nanorods.

    PubMed

    Li, Wen-qing; Sun, Chun-yang; Wang, Feng; Wang, Yu-cai; Zhai, Yi-wen; Liang, Meng; Liu, Wen-jing; Liu, Zhi-min; Wang, Jun; Sun, Fei

    2013-06-12

    During the process of human civilization, owning household pets has become increasingly popular. However, dogs and cats may be reservoirs or vectors of transmissible diseases to humans. Confronted with the overpopulation of pets, traditional contraception methods, surgical methods of sterilization, for animals are used, namely, ovariohysterectomy and orchidectomy. Therefore, a simple, nonsurgical, controllable, more effective and less expensive contraception method is highly desirable. In this study, we show that in situ testicular injection of methoxy poly(ethylene glycol)-modified gold nanorods with near-infrared irradiation in male mice can achieve short-lived or permanent male infertility. In a lower hyperthermia treatment, the morphology of testes and seminiferous tubules is only partly injured, and fertility indices are decreased to 10% at day 7, then recovered to 50% at day 60. In a higher hyperthermia treatment, the morphology of testes and seminiferous tubules are totally destroyed, and fertility indices are decreased to 0 at day 7. Overall, our results indicate a potential application of plasmonic nanomaterials for male contraception. PMID:23688274

  10. Examination about Influence for Precision of 3d Image Measurement from the Ground Control Point Measurement and Surface Matching

    NASA Astrophysics Data System (ADS)

    Anai, T.; Kochi, N.; Yamada, M.; Sasaki, T.; Otani, H.; Sasaki, D.; Nishimura, S.; Kimoto, K.; Yasui, N.

    2015-05-01

    As the 3D image measurement software is now widely used with the recent development of computer-vision technology, the 3D measurement from the image is now has acquired the application field from desktop objects as wide as the topography survey in large geographical areas. Especially, the orientation, which used to be a complicated process in the heretofore image measurement, can be now performed automatically by simply taking many pictures around the object. And in the case of fully textured object, the 3D measurement of surface features is now done all automatically from the orientated images, and greatly facilitated the acquisition of the dense 3D point cloud from images with high precision. With all this development in the background, in the case of small and the middle size objects, we are now furnishing the all-around 3D measurement by a single digital camera sold on the market. And we have also developed the technology of the topographical measurement with the air-borne images taken by a small UAV [1~5]. In this present study, in the case of the small size objects, we examine the accuracy of surface measurement (Matching) by the data of the experiments. And as to the topographic measurement, we examine the influence of GCP distribution on the accuracy by the data of the experiments. Besides, we examined the difference of the analytical results in each of the 3D image measurement software. This document reviews the processing flow of orientation and the 3D measurement of each software and explains the feature of the each software. And as to the verification of the precision of stereo-matching, we measured the test plane and the test sphere of the known form and assessed the result. As to the topography measurement, we used the air-borne image data photographed at the test field in Yadorigi of Matsuda City, Kanagawa Prefecture JAPAN. We have constructed Ground Control Point which measured by RTK-GPS and Total Station. And we show the results of analysis made

  11. Asynchronous decoding of finger position and of EMG during precision grip using CM cell activity: application to robot control.

    PubMed

    Ouanezar, Sofiane; Eskiizmirliler, Selim; Maier, Marc A

    2011-12-01

    Recent brain-machine interfaces (BMI) have demonstrated the use of intracortical signals for the kinematic control of robotic arms. However, for potential restoration of manual dexterity, two issues remain to be addressed: (1) Can hand and digit movements for dexterous manipulation be controlled in a similar way to arm movements? (2) Can the potentially large signal space for decoding of the many degrees of freedom (dof) of hand and digit movements be minimized? The first question addresses BMI control of dexterous prosthetic devices, while the second addresses the problem of whether few, but identified, neurons might provide adequate decoding. Asynchronous decoding of precision grip finger movement kinematics from identified corticomotoneuronal (CM) cell activity was performed with an artificial neural network (ANN). After training over a given session, the ANNs successfully decoded trial-by-trial movement kinematics. Average accuracy over sessions was in the order of 80% and 50% for data sets of two monkeys respectively. Decoding accuracy increased as a function of (1) number of simultaneously recorded CM cells used for prediction, and (2) size of the sliding input window. Subsequently, a robot digit actuated by pneumatic artificial muscles, fed with the predicted trajectory, mimicked the recorded movement offline. Furthermore, CM cell signals were used for decoding of time-varying hand muscle EMG activity. The performance of EMG prediction tended to increase if CM cells that facilitated this particular muscle (compared to CM cells that facilitated other muscles) were used. These results provide evidence that an anthropomorphic robot finger can be controlled offline by spike trains recorded from identified corticospinal neurons. This represents a step towards neuroprosthetic devices for dexterous hand movements. PMID:22262537

  12. Scattering Intensity and Directionality Probed Along Individual Zinc Oxide Nanorods with Precisely Controlled Light Polarization and Nanorod Orientation

    PubMed Central

    Choi, Daniel S.; Singh, Manpreet; Song, Sheng; Chang, Jae Young; Kang, Yongkoo; Hahm, Jong-in

    2015-01-01

    We elucidated the light-matter interaction of individual ZnO NRs with a monochromatic beam of linearly polarized light that scatters elastically from the ZnO NRs by performing forward scattering and back-aperture imaging in a dark-field setting. We precisely controlled the electric field vector of the incident light and the NR orientation within the plane of light interaction during both modes of measurement, and spatially resolved the scattering response from different interaction points along the NR long axis. We then discerned, for the first time, the effects of light polarization, analyzer angle, and NR orientation on the intensity and directionality of the optical responses both qualitatively and quantitatively along the length of the single ZnO NRs. We identified distinctive scattering profiles from individual ZnO NRs subject to incident light polarization with controlled NR orientation from the forward dark-field scattering and back-aperture imaging modes. The fundamental light interaction behavior of ZnO NRs is likely to govern their functional outcomes in photonics, optoelectronics, and sensor devices. Hence, our efforts provided much needed insight into unique optical responses from individual 1D ZnO nanomaterials, which could be highly beneficial in developing next-generation optoelectronic systems and optical biodetectors with improved device efficiency and sensitivity. PMID:26568952

  13. Precision performance lamp technology

    NASA Astrophysics Data System (ADS)

    Bell, Dean A.; Kiesa, James E.; Dean, Raymond A.

    1997-09-01

    A principal function of a lamp is to produce light output with designated spectra, intensity, and/or geometric radiation patterns. The function of a precision performance lamp is to go beyond these parameters and into the precision repeatability of performance. All lamps are not equal. There are a variety of incandescent lamps, from the vacuum incandescent indictor lamp to the precision lamp of a blood analyzer. In the past the definition of a precision lamp was described in terms of wattage, light center length (LCL), filament position, and/or spot alignment. This paper presents a new view of precision lamps through the discussion of a new segment of lamp design, which we term precision performance lamps. The definition of precision performance lamps will include (must include) the factors of a precision lamp. But what makes a precision lamp a precision performance lamp is the manner in which the design factors of amperage, mscp (mean spherical candlepower), efficacy (lumens/watt), life, not considered individually but rather considered collectively. There is a statistical bias in a precision performance lamp for each of these factors; taken individually and as a whole. When properly considered the results can be dramatic to the system design engineer, system production manage and the system end-user. It can be shown that for the lamp user, the use of precision performance lamps can translate to: (1) ease of system design, (2) simplification of electronics, (3) superior signal to noise ratios, (4) higher manufacturing yields, (5) lower system costs, (6) better product performance. The factors mentioned above are described along with their interdependent relationships. It is statistically shown how the benefits listed above are achievable. Examples are provided to illustrate how proper attention to precision performance lamp characteristics actually aid in system product design and manufacturing to build and market more, market acceptable product products in the

  14. Prediction of Kindergartners' Academic Achievement from Their Effortful Control and Emotionality: Evidence for Direct and Moderated Relations

    ERIC Educational Resources Information Center

    Valiente, Carlos; Lemery-Chalfant, Kathryn; Swanson, Jodi

    2010-01-01

    The relations between effortful control, emotionality (anger, sadness, and shyness), and academic achievement were examined in a short-term longitudinal study of 291 kindergartners. Teachers and parents reported on students' effortful control and emotionality. Students completed the Continuous Performance Task and the Letter-Word, Passage…

  15. Effects of an Emotion Control Treatment on Academic Emotions, Motivation and Achievement in an Online Mathematics Course

    ERIC Educational Resources Information Center

    Kim, ChanMin; Hodges, Charles B.

    2012-01-01

    We designed and developed an emotion control treatment and investigated its effects on college students' academic emotions, motivation, and achievement in an online remedial mathematics course. The treatment group showed more positive emotions of enjoyment and pride than the control group. The treatment group also showed a higher level of…

  16. Child Effortful Control, Teacher-Student Relationships, and Achievement in Academically At-Risk Children: Additive and Interactive Effects

    ERIC Educational Resources Information Center

    Liew, Jeffrey; Chen, Qi; Hughes, Jan N.

    2010-01-01

    The joint contributions of child effortful control (using inhibitory control and task accuracy as behavioral indices) and positive teacher-student relationships at first grade on reading and mathematics achievement at second grade were examined in 761 children who were predominantly from low-income and ethnic minority backgrounds and assessed to…

  17. Locus of Control and Academic Achievement: Integrating Social Learning Theory and Expectancy-Value Theory

    ERIC Educational Resources Information Center

    Youse, Keith Edward

    2012-01-01

    The current study examines predictors of math achievement and college graduation by integrating social learning theory and expectancy-value theory. Data came from a nationally-representative longitudinal database tracking 12,144 students over twelve years from 8th grade forward. Models for math achievement and college graduation were tested…

  18. The Effects of Formal Reasoning Ability, Locus of Control and Student Engagement on Science Process Achievement.

    ERIC Educational Resources Information Center

    Tobin, Kenneth G.; Capie, William

    This study investigated student variables likely to influence process skill learning. Specifically, relationships were explored concerning the following variables: (1) student engagement and science process achievement, (2) formal reasoning ability and student engagement, (3) formal reasoning ability and science process achievement, (4) student…

  19. The Impact of Parental Support, Behavioral Control, and Psychological Control on the Academic Achievement and Self-Esteem of African American and European American Adolescents.

    ERIC Educational Resources Information Center

    Bean, Roy A.; Bush, Kevin R.; McKenry, Patrick C.; Wilson, Stephan M.

    2003-01-01

    Relationships between adolescent functioning and parent support, behavioral control, and psychological control were examined among European American and African American adolescents. A number of correlations were significant, including maternal support and academic achievement and self-esteem, and paternal psychological control and self-esteem.…

  20. Engineered, Robust Polyelectrolyte Multilayers by Precise Control of Surface Potential for Designer Protein, Cell, and Bacteria Adsorption.

    PubMed

    Zhu, Xiaoying; Guo, Shifeng; He, Tao; Jiang, Shan; Jańczewski, Dominik; Vancso, G Julius

    2016-02-01

    Cross-linked layer-by-layer (LbL) assemblies with a precisely tuned surface ζ-potential were fabricated to control the adsorption of proteins, mammalian cells, and bacteria for different biomedical applications. Two weak polyions including a synthesized polyanion and polyethylenimine were assembled under controlled conditions and cross-linked to prepare three robust LbL films as model surfaces with similar roughness and water affinity but displaying negative, zero, and positive net charges at the physiological pH (7.4). These surfaces were tested for their abilities to adsorb proteins, including bovine serum albumin (BSA) and lysozyme (LYZ). In the adsorption tests, the LbL films bind more proteins with opposite charges but less of those with like charges, indicating that electrostatic interactions play a major role in protein adsorption. However, LYZ showed higher nonspecific adsorption than BSA, because of the specific behavior of LYZ molecules, such as stacked multilayer formation during adsorption. To exclude such stacking effects from experiments, protein molecules were covalently immobilized on AFM colloidal probes to measure the adhesion forces against the model surfaces utilizing direct protein molecule-surface contacts. The results confirmed the dominating role of electrostatic forces in protein adhesion. In fibroblast cell and bacteria adhesion tests, similar trends (high adhesion on positively charged surfaces, but much lower on neutral and negatively charged surfaces) were observed because the fibroblast cell and bacterial surfaces studied possess negative potentials. The cross-linked LbL films with improved stability and engineered surface charge described in this study provide an excellent platform to control the behavior of different charged objects and can be utilized in practical biomedical applications. PMID:26756285

  1. How the impact of median neuropathy on sensorimotor control capability of hands for diabetes: an achievable assessment from functional perspectives.

    PubMed

    Chiu, Haw-Yen; Hsu, Hsiu-Yun; Kuo, Li-Chieh; Su, Fong-Chin; Yu, Hui-I; Hua, Shih-Che; Lu, Chieh-Hsiang

    2014-01-01

    To comprehend the sensorimotor control ability in diabetic hands, this study investigated the sensation, motor function and precision pinch performances derived from a pinch-holding-up activity (PHUA) test of the hands of diabetic patients and healthy subjects. The precision, sensitivity and specificity of the PHUA test in the measurements of diabetic patients were also analyzed. We hypothesized that the diabetic hands would have impacts on the sensorimotor functions of the hand performances under functionally quantitative measurements. One hundred and fifty-nine patients with clinically defined diabetes mellitus (DM) and 95 age- and gender-matched healthy controls were included. Semmes-Weinstein monofilament (SWM), static and moving two-point discrimination (S2PD and M2PD), maximal pinch strength and precision pinch performance tests were conducted to evaluate the sensation, motor and sensorimotor status of the recruited hands. The results showed that there were significant differences (all p<0.05) in SWM, S2PD, M2PD and maximum pinch strength between the DM and control groups. A higher force ratio in the DM patients than in the controls (p<0.001) revealed a poor ability of pinch force adjustment in the DM patients. The percentage of maximal pinch strength was also significantly different (p<0.001) between the DM and control groups. The sensitivity, specificity and area under the receiver operating characteristic curve were 0.85, 0.51, and 0.724, respectively, for the PHUA test. Statistically significant degradations in sensory and motor functions and sensorimotor control ability were observed in the hands of the diabetic patients. The PHUA test could be feasibly used as a clinical tool to determine the sensorimotor function of the hands of diabetic patients from a functional perspective. PMID:24722361

  2. High-efficiency impurity activation by precise control of cooling rate during atmospheric pressure thermal plasma jet annealing of 4H-SiC wafer

    NASA Astrophysics Data System (ADS)

    Maruyama, Keisuke; Hanafusa, Hiroaki; Ashihara, Ryuhei; Hayashi, Shohei; Murakami, Hideki; Higashi, Seiichiro

    2015-06-01

    We have investigated high-temperature and rapid annealing of a silicon carbide (SiC) wafer by atmospheric pressure thermal plasma jet (TPJ) irradiation for impurity activation. To reduce the temperature gradient in the SiC wafer, a DC current preheating system and the lateral back-and-forth motion of the wafer were introduced. A maximum surface temperature of 1835 °C within 2.4 s without sample breakage was achieved, and aluminum (Al), phosphorus (P), and arsenic (As) activations in SiC were demonstrated. We have investigated precise control of heating rate (Rh) and cooling rate (Rc) during rapid annealing of P+-implanted 4H-SiC and its impact on impurity activation. No dependence of resistivity on Rh was observed, while increasing Rc significantly decreased resistivity. A minimum resistivity of 0.0025 Ω·cm and a maximum carrier concentration of 2.9 × 1020 cm-3 were obtained at Rc = 568 °C/s.

  3. Transparent conductive Nb-doped TiO2 films deposited by reactive dc sputtering using Ti-Nb alloy target, precisely controlled in the transition region using impedance feedback system

    NASA Astrophysics Data System (ADS)

    Oka, Nobuto; Sanno, Yuta; Jia, Junjun; Nakamura, Shin-ichi; Shigesato, Yuzo

    2014-05-01

    In this study, a stable reactive sputtering process using a Ti-Nb alloy target was achieved by applying a plasma impedance feedback system. High-quality transparent conductive Nb-doped TiO2 (Nb:TiO2) films were fabricated with high reproducibility. The films were deposited on unheated substrate and subsequently annealed at 873 K under vacuum conditions (below 6.0 × 10-4 Pa) for 1 h. During reactive sputtering, the feedback system precisely controlled the oxidation of the target surface in the so-called transition region. The post-annealing process yielded polycrystalline Nb:TiO2 films whose lattice defects decreased with increasing Nb concentration. An extremely low resistivity (7.2 × 10-4 Ω cm) was achieved for Nb:TiO2 film with 60-70% transmittance in the visible region. The reactive sputtering using Ti-Nb alloys is considered to be a strong candidate for industrial-scale thin-film deposition. Furthermore, it can also control the metal-oxygen stoichiometry of Nb:TiO2 films precisely to achieve desirable properties for each industrial application.

  4. Locus of Control or Self-Esteem; Which One is the Best Predictor of Academic Achievement in Iranian College Students

    PubMed Central

    Hosseini, Seyyed Nasrollah; Mirzaei Alavijeh, Mehdi; Karami Matin, Behzad; Hamzeh, Behrooz; Ashtarian, Hossein; Jalilian, Farzad

    2016-01-01

    Background Self-esteem and behavioral consequences, which are due to external or internal locus of control, are effective on academic achievement of students. Objectives The aim of this study was to determine the prediction of locus of control and self-esteem in academic achievement among the students. Materials and Methods This cross-sectional study was conducted on 300 college students in Kermanshah University of Medical Sciences in 2014. Data collection tools were in three sections: demographic, Rotter internal-external locus of control scale and Coopersmith self-esteem inventory. Data were analyzed using the SPSS software version 21. Results Results showed that 29.8% and 76.2% of the participants had internal locus of control, and high self-esteem, respectively. There was a significant correlation between self-esteem, locus of control and academic achievement of the students. Self-esteem accounted for 39.5% of the variation in academic achievement. Conclusions It seems that interventions to increase self-esteem among student can help improve academic achievement among them. PMID:27284277

  5. Child Effortful Control, Teacher-student Relationships, and Achievement in Academically At-risk Children: Additive and Interactive Effects

    PubMed Central

    Liew, Jeffrey; Chen, Qi; Hughes, Jan N.

    2009-01-01

    The joint contributions of child effortful control (using inhibitory control and task accuracy as behavioral indices) and positive teacher-student relationships at first grade on reading and mathematics achievement at second grade were examined in 761 children who were predominantly from low-income and ethnic minority backgrounds and assessed to be academically at-risk at entry to first grade. Analyses accounted for clustering effects, covariates, baselines of effortful control measures, and prior levels of achievement. Even with such conservative statistical controls, interactive effects were found for task accuracy and positive teacher-student relationships on future achievement. Results suggest that task accuracy served as a protective factor so that children with high task accuracy performed well academically despite not having positive teacher-student relationships. Further, positive teacher-student relationships served as a compensatory factor so that children with low task accuracy performed just as well as those with high task accuracy if they were paired with a positive and supportive teacher. Importantly, results indicate that the influence of positive teacher-student relationships on future achievement was most pronounced for students with low effortful control on tasks that require fine motor skills, accuracy, and attention-related skills. Study results have implications for narrowing achievement disparities for academically at-risk children. PMID:20161421

  6. Three-dimensional imaging for precise structural control of Si quantum dot networks for all-Si solar cells

    NASA Astrophysics Data System (ADS)

    Kourkoutis, Lena F.; Hao, Xiaojing; Huang, Shujuan; Puthen-Veettil, Binesh; Conibeer, Gavin; Green, Martin A.; Perez-Wurfl, Ivan

    2013-07-01

    All-Si tandem solar cells based on Si quantum dots (QDs) are a promising approach to future high-performance, thin film solar cells using abundant, stable and non-toxic materials. An important prerequisite to achieve a high conversion efficiency in such cells is the ability to control the geometry of the Si QD network. This includes the ability to control both, the size and arrangement of Si QDs embedded in a higher bandgap matrix. Using plasmon tomography we show the size, shape and density of Si QDs, that form in Si rich oxide (SRO)/SiO2 multilayers upon annealing, can be controlled by varying the SRO stoichiometry. Smaller, more spherical QDs of higher densities are obtained at lower Si concentrations. In richer SRO layers ellipsoidal QDs tend to form. Using electronic structure calculations within the effective mass approximation we show that ellipsoidal QDs give rise to reduced inter-QD coupling in the layer. Efficient carrier transport via mini-bands is in this case more likely across the multilayers provided the SiO2 spacer layer is thin enough to allow coupling in the vertical direction.All-Si tandem solar cells based on Si quantum dots (QDs) are a promising approach to future high-performance, thin film solar cells using abundant, stable and non-toxic materials. An important prerequisite to achieve a high conversion efficiency in such cells is the ability to control the geometry of the Si QD network. This includes the ability to control both, the size and arrangement of Si QDs embedded in a higher bandgap matrix. Using plasmon tomography we show the size, shape and density of Si QDs, that form in Si rich oxide (SRO)/SiO2 multilayers upon annealing, can be controlled by varying the SRO stoichiometry. Smaller, more spherical QDs of higher densities are obtained at lower Si concentrations. In richer SRO layers ellipsoidal QDs tend to form. Using electronic structure calculations within the effective mass approximation we show that ellipsoidal QDs give rise to

  7. Effect of Column Disorder on Carrier Transport in Columnar Discotic Liquid Crystal Evaluated by Applying Precisely Controlled Shear Stress

    NASA Astrophysics Data System (ADS)

    Kim, Jaeki; Yamasaki, Naoyuki; Hayashi, Takeshi; Katayama, Mitsuyoshi; Yoshida, Hiroyuki; Moritake, Hiroshi; Fujii, Akihiko; Ozaki, Masanori

    2013-10-01

    The effect of column disorder on carrier drift mobility in columnar discotic liquid crystals has been investigated by applying a precisely controlled oscillating shear stress. Drift mobilities on the order of 10-1 cm2.V-1.s-1 were confirmed for positive and negative carriers in the columnar phase of 1,4,8,11,15,18,22,25-octahexylphthalocyanine in a well-aligned homeotropic geometry, in which the columnar axis was perfectly perpendicular to substrates with an electrode. A slight tilt of the columnar axis upon applying shear stress led to a marked decrease in electronic carrier mobility from 10-1 to less than 10-6 cm2.V-1.s-1, and transport was only confirmed for positive ion carriers. This result indicates that a uniform shear stress blocks the carrier transport path in the entire area of the electrode, and one-dimensional carrier transport path along the columns is easily hindered in columnar discotic liquid crystals.

  8. [On Chinese medicine quality precision in expectation].

    PubMed

    Shi, Ren-bing; Wang, Yong-yan; Lv, Song-tao

    2015-09-01

    According to the correlative analyses on Chinese medicine essence, dosage forms and quality control level, it expounds the precise concept of Chinese medicine, and its quality advantages and characteristics in this paper, furthermore discusses how to achieve the ideal drugs and Chinese medicine quality precision in expectation. Base on the Chinese medicine essence, using the concept of nature medicine and its drug system to construct Chinese medicine effective material basis and its drugs, with the correlative analyses of whole view and reductionism, the problems of uncertainty quality of original natural medicinal resources and preparations may well be solved, and further with the macroscopic to microcosmic construction of drug system, the precision in expectations of Chinese medicine quality and higher production lever may well be achieved. PMID:26978969

  9. Frequency scanning interferometry with nanometer precision using a vertical-cavity surface-emitting laser diode under scanning speed control

    NASA Astrophysics Data System (ADS)

    Kakuma, Seiichi

    2015-12-01

    Frequency scanning interferometry technique with a nanometer precision using a vertical-cavity surface-emitting laser diode (VCSEL) is presented. Since the frequency scanning of the VCSEL is linearized by the phase-locked-loop technique, the gradient of the interference fringe order can be precisely determined using linear least squares fitting. This enables a length measurement with a precision better than a quarter wavelength, and the absolute fringe number including the integer part at the atomic transition spectrum (rubidium-D2 line) is accurately determined. The validity of the method is demonstrated by excellent results of block gauge measurement with a root mean square error better than 5 nm.

  10. Auto Focus and Leveling Control of Large-Scale High-Precision Scan-Stage Using Driving Force and Surface Shape of the Stage

    NASA Astrophysics Data System (ADS)

    Sakata, Koichi; Fujimoto, Hiroshi; Ohtomo, Takeshi; Saiki, Kazuaki

    The large-scale high-precision scan-stage is industrial equipment for microfabrications. The scan-stage needs not only fast and precise positioning but also the attitude control of the stage. The attitude of the stage is disturbed by the stage thrust in scanning. However, the sampling time of output is much longer than the sampling time of control input by DSP because image sensors are employed in the output encoder. It is difficult to reject the disturbances by single-rate feedback system. In this paper, we proposed the attitude control based on PTC (perfect tracking control) using driving force and surface shape of the stage. Finally, simulations and experiments are performed to show the advantages of the proposed control system.

  11. Bandwidth efficient coding: Theoretical limits and real achievements. Error control techniques for satellite and space communications

    NASA Technical Reports Server (NTRS)

    Costello, Daniel J., Jr.; Courturier, Servanne; Levy, Yannick; Mills, Diane G.; Perez, Lance C.; Wang, Fu-Quan

    1993-01-01

    In his seminal 1948 paper 'The Mathematical Theory of Communication,' Claude E. Shannon derived the 'channel coding theorem' which has an explicit upper bound, called the channel capacity, on the rate at which 'information' could be transmitted reliably on a given communication channel. Shannon's result was an existence theorem and did not give specific codes to achieve the bound. Some skeptics have claimed that the dramatic performance improvements predicted by Shannon are not achievable in practice. The advances made in the area of coded modulation in the past decade have made communications engineers optimistic about the possibility of achieving or at least coming close to channel capacity. Here we consider the possibility in the light of current research results.

  12. Tobacco control efforts in the Gulf Cooperation Council countries: achievements and challenges.

    PubMed

    Hassounah, S; Rawaf, D; Khoja, T; Rawaf, S; Hussein, M S; Qidwai, W; Majeed, A

    2014-08-01

    This paper reports a review into the current state of tobacco use, governance and national commitment for control, and current intervention frameworks in place to reduce the use of tobacco among the populations of the Gulf Cooperation Council (GCC) member states and Yemen. It further reviews structured policy-oriented interventions (in line with the MPOWER package of 6 evidence-based tobacco control measures) that represent government actions to strengthen, implement and manage tobacco control programmes and to address the growing epidemic of tobacco use. Our findings show that tobacco control in the GCC countries has witnessed real progress over the past decades. These are still early days but they indicate steps in the right direction. Future investment in implementation and enforcement of the Framework Convention on Tobacco Control, production of robust tobacco control legislation and the establishment of universally available tobacco cessation services are essential to sustain and strengthen tobacco control in the GCC region. PMID:25150358

  13. Advanced, Integrated Control for Building Operations to Achieve 40% Energy Saving

    SciTech Connect

    Lu, Yan; Song, Zhen; Loftness, Vivian; Ji, Kun; Zheng, Sam; Lasternas, Bertrand; Marion, Flore; Yuebin, Yu

    2012-10-15

    We developed and demonstrated a software based integrated advanced building control platform called Smart Energy Box (SEB), which can coordinate building subsystem controls, integrate variety of energy optimization algorithms and provide proactive and collaborative energy management and control for building operations using weather and occupancy information. The integrated control system is a low cost solution and also features: Scalable component based architecture allows to build a solution for different building control system configurations with needed components; Open Architecture with a central data repository for data exchange among runtime components; Extendible to accommodate variety of communication protocols. Optimal building control for central loads, distributed loads and onsite energy resource; uses web server as a loosely coupled way to engage both building operators and building occupants in collaboration for energy conservation. Based on the open platform of SEB, we have investigated and evaluated a variety of operation and energy saving control strategies on Carnegie Mellon University Intelligent Work place which is equipped with alternative cooling/heating/ventilation/lighting methods, including radiant mullions, radiant cooling/heating ceiling panels, cool waves, dedicated ventilation unit, motorized window and blinds, and external louvers. Based on the validation results of these control strategies, they were integrated in SEB in a collaborative and dynamic way. This advanced control system was programmed and computer tested with a model of the Intelligent Workplace's northern section (IWn). The advanced control program was then installed in the IWn control system; the performance was measured and compared with that of the state of the art control system to verify the overall energy savings great than 40%. In addition advanced human machine interfaces (HMI's) were developed to communicate both with building occupants and

  14. Fast-adapting mechanoreceptors are important for force control in precision grip but not for sensorimotor memory.

    PubMed

    Park, Susanna B; Davare, Marco; Falla, Marika; Kennedy, William R; Selim, Mona M; Wendelschafer-Crabb, Gwen; Koltzenburg, Martin

    2016-06-01

    Sensory feedback from cutaneous mechanoreceptors in the fingertips is important in effective object manipulation, allowing appropriate scaling of grip and load forces during precision grip. However, the role of mechanoreceptor subtypes in these tasks remains incompletely understood. To address this issue, psychophysical tasks that may specifically assess function of type I fast-adapting (FAI) and slowly adapting (SAI) mechanoreceptors were used with object manipulation experiments to examine the regulation of grip force control in an experimental model of graded reduction in tactile sensitivity (healthy volunteers wearing 2 layers of latex gloves). With gloves, tactile sensitivity decreased significantly from 1.9 ± 0.4 to 12.3 ± 2.2 μm in the Bumps task assessing function of FAI afferents but not in a grating orientation task assessing SAI afferents (1.6 ± 0.1 to 1.8 ± 0.2 mm). Six axis force/torque sensors measured peak grip (PGF) and load (PLF) forces generated by the fingertips during a grip-lift task. With gloves there was a significant increase of PGF (14 ± 6%), PLF (17 ± 5%), and grip and load force rates (26 ± 8%, 20 ± 8%). A variable-weight series task was used to examine sensorimotor memory. There was a 20% increase in PGF when the lift of a light object was preceded by a heavy relative to a light object. This relationship was not significantly altered when lifting with gloves, suggesting that the addition of gloves did not change sensorimotor memory effects. We conclude that FAI fibers may be important for the online force scaling but not for the buildup of a sensorimotor memory. PMID:27052582

  15. Two-dimensional laser servoing for precision motion control of an ODV robotic license plate recognition system

    NASA Astrophysics Data System (ADS)

    Song, Zhen; Moore, Kevin L.; Chen, YangQuan; Bahl, Vikas

    2003-09-01

    As an outgrowth of series of projects focused on mobility of unmanned ground vehicles (UGV), an omni-directional (ODV), multi-robot, autonomous mobile parking security system has been developed. The system has two types of robots: the low-profile Omni-Directional Inspection System (ODIS), which can be used for under-vehicle inspections, and the mid-sized T4 robot, which serves as a ``marsupial mothership'' for the ODIS vehicles and performs coarse resolution inspection. A key task for the T4 robot is license plate recognition (LPR). For a successful LPR task without compromising the recognition rate, the robot must be able to identify the bumper locations of vehicles in the parking area and then precisely position the LPR camera relative to the bumper. This paper describes a 2D-laser scanner based approach to bumper identification and laser servoing for the T4 robot. The system uses a gimbal-mounted scanning laser. As the T4 robot travels down a row of parking stalls, data is collected from the laser every 100ms. For each parking stall in the range of the laser during the scan, the data is matched to a ``bumper box'' corresponding to where a car bumper is expected, resulting in a point cloud of data corresponding to a vehicle bumper for each stall. Next, recursive line-fitting algorithms are used to determine a line for the data in each stall's ``bumper box.'' The fitting technique uses Hough based transforms, which are robust against segmentation problems and fast enough for real-time line fitting. Once a bumper line is fitted with an acceptable confidence, the bumper location is passed to the T4 motion controller, which moves to position the LPR camera properly relative to the bumper. The paper includes examples and results that show the effectiveness of the technique, including its ability to work in real-time.

  16. Calibration of an instrumented treadmill using a precision-controlled device with artificial neural network-based error corrections.

    PubMed

    Hsieh, Hong-Jung; Lin, Hsiu-Chen; Lu, Hsuan-Lun; Chen, Ting-Yi; Lu, Tung-Wu

    2016-03-01

    Instrumented treadmills (ITs) are used to measure reaction forces (RF) and center of pressure (COP) movements for gait and balance assessment. Regular in situ calibration is essential to ensure their accuracy and to identify conditions when a factory re-calibration is needed. The current study aimed to develop and calibrate in situ an IT using a portable, precision-controlled calibration device with an artificial neural network (ANN)-based correction method. The calibration device was used to apply static and dynamic calibrating loads to the surface of the IT at 189 and 25 grid-points, respectively, at four belt speeds (0, 4, 6 and 8 km/h) without the need of a preset template. Part of the applied and measured RF and COP were used to train a threelayered, back-propagation ANN model while the rest of the data were used to evaluate the performance of the ANN. The percent errors of Fz and errors of the Px and Py were significantly decreased from a maximum of -1.15%, -1.64 mm and -0.73 mm to 0.02%, 0.02 mm and 0.03 mm during static calibration, respectively. During dynamic calibration, the corresponding values were decreasing from -3.65%, 2.58 mm and -4.92 mm to 0.30%, -0.14 mm and -0.47 mm, respectively. The results suggest that the calibration device and associated ANN will be useful for correcting measurement errors in vertical loads and COP for ITs. PMID:26979909

  17. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... for Major Sources in Accordance With Clean Air Act Sections, Sections 112(g) and 112(j) § 63.43... achieving such emission reduction and any non-air quality health and environmental impacts and energy..., and analysis of cost and non-air quality health environmental impacts or energy requirements for...

  18. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for Major Sources in Accordance With Clean Air Act Sections, Sections 112(g) and 112(j) § 63.43... achieving such emission reduction and any non-air quality health and environmental impacts and energy..., and analysis of cost and non-air quality health environmental impacts or energy requirements for...

  19. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... for Major Sources in Accordance With Clean Air Act Sections, Sections 112(g) and 112(j) § 63.43... achieving such emission reduction and any non-air quality health and environmental impacts and energy..., and analysis of cost and non-air quality health environmental impacts or energy requirements for...

  20. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... for Major Sources in Accordance With Clean Air Act Sections, Sections 112(g) and 112(j) § 63.43... achieving such emission reduction and any non-air quality health and environmental impacts and energy..., and analysis of cost and non-air quality health environmental impacts or energy requirements for...

  1. Effects of Autonomy Supportive vs. Controlling Teachers' Behavior on Students' Achievements

    ERIC Educational Resources Information Center

    Hofferber, Natalia; Eckes, Alexander; Wilde, Matthias

    2014-01-01

    Grolnick and Ryan (1987) assume that an autonomy supportive environment leads to higher learner engagement and thus to greater achievements and deeper understanding of content. In school, knowledge acquisition (rote learning as well as conceptual learning) are regarded as most important. In this study, we examined the effects of teachers' autonomy…

  2. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for Major Sources in Accordance With Clean Air Act Sections, Sections 112(g) and 112(j) § 63.43... achieving such emission reduction and any non-air quality health and environmental impacts and energy..., and analysis of cost and non-air quality health environmental impacts or energy requirements for...

  3. Effects of Achievement, Evaluative Feedback, and Locus of Control on Children's Expectations.

    ERIC Educational Resources Information Center

    Midlarsky, Elizabeth; McKnight, Lynda Bidlake

    1980-01-01

    Results indicated that expectations concerning success were determined by past achievement and by evaluative feedback. Immediate past performance had a stronger relative influence on expectations and performance than evaluative feedback. Feedback had a relatively greater effect on self-evaluation. (Author/DB)

  4. An ultra-compact and low-power oven-controlled crystal oscillator design for precision timing applications.

    PubMed

    Lim, Jaehyun; Kim, Hyunsoo; Jackson, Thomas; Choi, Kyusun; Kenny, David

    2010-09-01

    A novel design for a chip-scale miniature oven-controlled crystal oscillator (OCXO) is presented. In this design, all the main components of an OCXO--consisting of an oscillator, a temperature sensor, a heater, and temperature-control circuitry--are integrated on a single CMOS chip. The OCXO package size can be reduced significantly with this design, because the resonator does not require a separate package and most of the circuitry is integrated on a single CMOS chip. Other characteristics such as power consumption and warm-up time are also improved. Two different types of quartz resonators, an AT-cut tab mesa-type quartz crystal and a frame enclosed resonator, allow miniaturization of the OCXO structure. Neither of these quartz resonator types requires a separate package inside the oven structure; therefore, they can each be directly integrated with the custom-designed CMOS chip. The miniature OCXO achieves a frequency stability of +/- 0.35 ppm with an AT-cut tab mesa-type quartz crystal in the temperature range of 0 °C to 60 °C. The maximum power consumption of this miniature OCXO is 1.2 W at start-up and 303 mW at steady state. The warm-up time to reach the steady state is 190 s. These results using the proposed design are better than or the same as high-frequency commercial OCXOs. PMID:20875980

  5. Using Confirmatory Factor Analysis to Understand Executive Control in Preschool Children: Sources of Variation in Emergent Mathematic Achievement

    ERIC Educational Resources Information Center

    Bull, Rebecca; Espy, Kimberly Andrews; Wiebe, Sandra A.; Sheffield, Tiffany D.; Nelson, Jennifer Mize

    2011-01-01

    Latent variable modeling methods have demonstrated utility for understanding the structure of executive control (EC) across development. These methods are utilized to better characterize the relation between EC and mathematics achievement in the preschool period, and to understand contributing sources of individual variation. Using the sample and…

  6. High-School Students' Need for Cognition, Self-Control Capacity, and School Achievement: Testing a Mediation Hypothesis

    ERIC Educational Resources Information Center

    Bertrams, Alex; Dickhauser, Oliver

    2009-01-01

    In the present article, we examine the hypothesis that high-school students' motivation to engage in cognitive endeavors (i.e., their need for cognition; NFC) is positively related to their dispositional self-control capacity. Furthermore, we test the prediction that the relation between NFC and school achievement is mediated by self-control…

  7. Using Valid and Invalid Experimental Designs to Teach the Control of Variables Strategy in Higher and Lower Achieving Classrooms

    ERIC Educational Resources Information Center

    Lorch, Robert F., Jr.; Lorch, Elizabeth P.; Freer, Benjamin Dunham; Dunlap, Emily E.; Hodell, Emily C.; Calderhead, William J.

    2014-01-01

    Students (n = 1,069) from 60 4th-grade classrooms were taught the control of variables strategy (CVS) for designing experiments. Half of the classrooms were in schools that performed well on a state-mandated test of science achievement, and half were in schools that performed relatively poorly. Three teaching interventions were compared: an…

  8. 40 CFR 63.55 - Maximum achievable control technology (MACT) determinations for affected sources subject to case...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air Act Sections... quality health and environmental impacts and energy requirements, determines is achievable by affected... and any non-air quality health and environmental impacts and energy requirements, determines...

  9. 40 CFR 63.55 - Maximum achievable control technology (MACT) determinations for affected sources subject to case...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air Act Sections... quality health and environmental impacts and energy requirements, determines is achievable by affected... and any non-air quality health and environmental impacts and energy requirements, determines...

  10. 40 CFR 63.55 - Maximum achievable control technology (MACT) determinations for affected sources subject to case...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air Act Sections... quality health and environmental impacts and energy requirements, determines is achievable by affected... and any non-air quality health and environmental impacts and energy requirements, determines...

  11. 40 CFR 63.55 - Maximum achievable control technology (MACT) determinations for affected sources subject to case...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air Act Sections... quality health and environmental impacts and energy requirements, determines is achievable by affected... and any non-air quality health and environmental impacts and energy requirements, determines...

  12. Students' Commitment, Engagement and Locus of Control as Predictor of Academic Achievement at Higher Education Level

    ERIC Educational Resources Information Center

    Sarwar, Muhammad; Ashrafi, Ghulam Muhammad

    2014-01-01

    The purpose of this study was to analyze Students' Commitment, Engagement and Locus of Control as predictors of Academic Achievement at Higher Education Level. We used analytical model and conclusive research approach to conduct study and survey method for data collection. We selected 369 students using multistage sampling technique from…

  13. 40 CFR 63.55 - Maximum achievable control technology (MACT) determinations for affected sources subject to case...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air Act Sections... quality health and environmental impacts and energy requirements, determines is achievable by affected... and any non-air quality health and environmental impacts and energy requirements, determines...

  14. A Randomized Controlled Design Investigating the Effects of Classroom-Based Physical Activity on Children's Fluid Intelligence and Achievement

    ERIC Educational Resources Information Center

    Fedewa, Alicia L.; Ahn, Soyeon; Erwin, Heather; Davis, Matthew C.

    2015-01-01

    Existing literature shows promising effects of physical activity on children's cognitive outcomes. This study assessed via a randomized, controlled design whether additional curricular physical activity during the school day resulted in gains for children's fluid intelligence and standardized achievement outcomes. Participants were children…

  15. The Effects of Diagnosis, Remediation and Locus of Control on Achievement, Retention, and Attitudes of Middle School Science Students.

    ERIC Educational Resources Information Center

    Saunders, Ramona L.; Yeany, Russell H.

    Reported is a study designed to determine the effects of diagnostic testing followed by prescribed remediation on the immediate and retained science achievement of middle school students, and to determine if effects of treatment were consistent across students' race and locus of control (LOC) levels. Three intact seventh-grade science classes were…

  16. Optimal cut-off value of alanine aminotransferase level to precisely estimate the presence of fatty liver in patients with poorly controlled type 2 diabetes.

    PubMed

    Tanabe, Akihito; Tatsumi, Fuminori; Okauchi, Seizo; Yabe, Hiroki; Tsuda, Tomohiro; Okutani, Kazuma; Yamashita, Kazuki; Nakashima, Koji; Kaku, Kohei; Kaneto, Hideaki

    2016-07-01

    Optimal cut-off value of ALT level to precisely estimate the presence of fatty liver was as low as 28.0 U/L. We should consider the possibility of fatty liver even when ALT level is within normal range in subjects with poorly controlled type 2 diabetes. PMID:27373695

  17. High Self-Control Predicts More Positive Emotions, Better Engagement, and Higher Achievement in School

    ERIC Educational Resources Information Center

    King, Ronnel B.; Gaerlan, Marianne Jennifer M.

    2014-01-01

    The control-value theory of academic emotions has emerged as a useful framework for studying the antecedents and consequences of different emotions in school. This framework focuses on the role of control-related and value-related appraisals as proximal antecedents of emotions. In this study, we take an individual differences approach to examine…

  18. Achievement of a low-outgassing white paint system for spacecraft thermal control

    NASA Technical Reports Server (NTRS)

    Seidenberg, B.; Park, J. J.; Clatterbuck, C.

    1972-01-01

    Test results and data for achieving a low-outgassing polymer resin suitable for potting or a paint pigment are presented. The resin, prepared in 0.5-kg (1-lb) batches, is acceptable for spacecraft use; its weight loss is less than 0.5 percent, and the volatile condensable materials are less than 0.05 percent. The paint adheres to a primed fiber glass or aluminum substrate. Results of UV irradiation, electron and proton radiation, and thermal cycling are presented.

  19. Stability precision dynamic testing system on artillery

    NASA Astrophysics Data System (ADS)

    Wang, Chunyan; Li, Bo

    2014-12-01

    Dynamic feature of Weapon equipments is one of important performance index for evaluating the performance of the whole weapon system. The construction of target range in our country in fire control dynamic testing is relatively backward; therefore, it has greatly influenced the evaluation on the fire control system. In order to solve this problem, it's urgent to develop a new testing instrument so as to adjust to the armament research process and promote weapon system working more efficiently and thereby meeting the needs of modernization in national defense. This paper proposes a new measure which is used to test the stability precision of the fire control system, and it is installed on the moving base. Using the method, we develop a testing system which can test the stability precision of the fire control system and achieve a high precision results after testing. The innovation of the system is we can receive the image not only by CCD, but our eyes. It also adopts digital image-forming and image processing technique for real-time measurement and storing of the target information; it simultaneously adopts the method adjusting the platform and the corresponding fixture mounted on a sample to measure the stable precision and the precision of corner of stabilizator. In this paper, we make a description on the construction of the system and the idea of the designing of the optical system. Finally, we introduce the actual application of the system and testing results.

  20. Robust, integrated computational control of NMR experiments to achieve optimal assignment by ADAPT-NMR.

    PubMed

    Bahrami, Arash; Tonelli, Marco; Sahu, Sarata C; Singarapu, Kiran K; Eghbalnia, Hamid R; Markley, John L

    2012-01-01

    ADAPT-NMR (Assignment-directed Data collection Algorithm utilizing a Probabilistic Toolkit in NMR) represents a groundbreaking prototype for automated protein structure determination by nuclear magnetic resonance (NMR) spectroscopy. With a [(13)C,(15)N]-labeled protein sample loaded into the NMR spectrometer, ADAPT-NMR delivers complete backbone resonance assignments and secondary structure in an optimal fashion without human intervention. ADAPT-NMR achieves this by implementing a strategy in which the goal of optimal assignment in each step determines the subsequent step by analyzing the current sum of available data. ADAPT-NMR is the first iterative and fully automated approach designed specifically for the optimal assignment of proteins with fast data collection as a byproduct of this goal. ADAPT-NMR evaluates the current spectral information, and uses a goal-directed objective function to select the optimal next data collection step(s) and then directs the NMR spectrometer to collect the selected data set. ADAPT-NMR extracts peak positions from the newly collected data and uses this information in updating the analysis resonance assignments and secondary structure. The goal-directed objective function then defines the next data collection step. The procedure continues until the collected data support comprehensive peak identification, resonance assignments at the desired level of completeness, and protein secondary structure. We present test cases in which ADAPT-NMR achieved results in two days or less that would have taken two months or more by manual approaches. PMID:22427982

  1. Precision displacement reference system

    DOEpatents

    Bieg, Lothar F.; Dubois, Robert R.; Strother, Jerry D.

    2000-02-22

    A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

  2. High School Students' Perceptions of EFL Teacher Control Orientations and Their English Academic Achievement

    ERIC Educational Resources Information Center

    Kiany, Gholam Reza; Shayestefar, Parvaneh

    2011-01-01

    Background: Theories distinguish between student-initiated and teacher-initiated regulation of students' learning activities, or between "strong, shared, or loose teacher control" during the completion of learning tasks. Empirical validations for such distinctions are scarce, however. Aim: The present study aimed at (a) investigating students'…

  3. Beyond Control of Variables: What Needs to Develop to Achieve Skilled Scientific Thinking?

    ERIC Educational Resources Information Center

    Kuhn, Deanna; Iordanou, Kalypso; Pease, Maria; Wirkala, Clarice

    2008-01-01

    We identify three aspects of scientific thinking beyond the control-of-variables strategy that we claim are essential for students to master as a foundation for skilled scientific thinking. The first is strategic and involves the ability to coordinate effects of multiple causal influences on an outcome. The second is a mature understanding of the…

  4. Achieving control and interoperability through unified model-based systems and software engineering

    NASA Technical Reports Server (NTRS)

    Rasmussen, Robert; Ingham, Michel; Dvorak, Daniel

    2005-01-01

    Control and interoperation of complex systems is one of the most difficult challenges facing NASA's Exploration Systems Mission Directorate. An integrated but diverse array of vehicles, habitats, and supporting facilities, evolving over the long course of the enterprise, must perform ever more complex tasks while moving steadily away from the sphere of ground support and intervention.

  5. A Study to Investigate the Relationship between Locus of Control and Academic Achievement of Students

    ERIC Educational Resources Information Center

    Gujjar, Aijaz Ahmed; Aijaz, Rukhma

    2014-01-01

    Motivation is regarded as the alpha and omega of learning. It is the heart of teaching learning process. Motivation is defined as an internal state that arouses, directs, and maintains the behavior over time. Thus motivation is the pivotal component of learning and locus of control which is one of the important factors it stems from. Locus of…

  6. Precision translator

    DOEpatents

    Reedy, Robert P.; Crawford, Daniel W.

    1984-01-01

    A precision translator for focusing a beam of light on the end of a glass fiber which includes two turning fork-like members rigidly connected to each other. These members have two prongs each with its separation adjusted by a screw, thereby adjusting the orthogonal positioning of a glass fiber attached to one of the members. This translator is made of simple parts with capability to keep adjustment even in condition of rough handling.

  7. Precision translator

    DOEpatents

    Reedy, R.P.; Crawford, D.W.

    1982-03-09

    A precision translator for focusing a beam of light on the end of a glass fiber which includes two turning fork-like members rigidly connected to each other. These members have two prongs each with its separation adjusted by a screw, thereby adjusting the orthogonal positioning of a glass fiber attached to one of the members. This translator is made of simple parts with capability to keep adjustment even in condition of rough handling.

  8. Achieving asthma control with ICS/LABA: A review of strategies for asthma management and prevention.

    PubMed

    Aalbers, René; Vogelmeier, Claus; Kuna, Piotr

    2016-02-01

    Maintenance treatment with an inhaled corticosteroid (ICS) and a long-acting β2-agonist (LABA) is recommended for patients whose asthma is not controlled with a low-to-moderate dose of ICS alone; a separate reliever medication is used on an as-needed basis. The Gaining Optimal Asthma ControL (GOAL) study demonstrated that salmeterol/fluticasone maintenance treatment can improve asthma control and reduce future risk compared with fluticasone alone, although the dose escalation design of this study meant that most patients treated with salmeterol/fluticasone were receiving the highest dose of ICS at the end of the study. Similarly, budesonide/formoterol maintenance therapy improved asthma control and reduced future risk compared with budesonide alone in the Formoterol and Corticosteroids Establishing Therapy (FACET) study. An alternative approach to asthma management is to use an ICS/LABA for both maintenance and reliever therapy. A large body of clinical evidence has shown that the use of budesonide/formoterol in this way improves both current control and reduces future risk compared with ICS/LABA plus as-needed short-acting β2-agonist (SABA), even when patients receive lower maintenance doses of ICS as part of the maintenance and reliever therapy regimen. In addition, one study has shown that beclometasone/formoterol maintenance and reliever therapy reduces exacerbations more effectively than beclometasone/formoterol plus as-needed SABA. The use of ICS/LABA as both maintenance and reliever therapy ensures that an increase in reliever use in response to worsening symptoms is automatically matched by an increase in ICS. PMID:26614594

  9. Nanomechanical control of properties of biological membranes achieved by rodlike magnetic nanoparticles in a superlow-frequency magnetic field

    NASA Astrophysics Data System (ADS)

    Golovin, Yu. I.; Klyachko, N. L.; Gribanovskii, S. L.; Golovin, D. Yu.; Samodurov, A. A.; Majouga, A. G.; Sokolsky-Papkov, M.; Kabanov, A. V.

    2015-05-01

    It is proposed to use single-domain rodlike magnetic nanoparticles (MNPs) as mediators for nanomechanical control of properties of biological membranes and cells on the molecular or cellular level by exposing them to a homogeneous nonheating low-frequency magnetic field (AC MF). The trigger effect is achieved due to rotatory-oscillatory motion of MNPs in the AC MF, which causes the needed deformations in macromolecules of the membrane interacting with these MNPs.

  10. Effect of Aerobic Exercise on Cognition, Academic Achievement, and Psychosocial Function in Children: A Systematic Review of Randomized Control Trials

    PubMed Central

    Lees, Caitlin

    2013-01-01

    Introduction Although the effects of aerobic physical activity (APA) on children’s physical health is well characterized, the effect of aerobic physical activity on cognition, academic achievement, and psychosocial function has not yet been established. This systematic review provides an overview of research elucidating the relationship between aerobic physical activity and children’s cognition, academic achievement, and psychosocial function. Methods A systematic review of English articles was performed in April 2013 using MEDLINE, Cochrane, PsycINFO, SPORTDiscus, and EMBASE. Additional studies were identified through back-searching bibliographies. Only randomized control trials with an intervention of aerobic physical activity in children younger than 19 years that measured psychological, behavioral, cognitive, or academic outcomes were included. Results We found 8 relevant randomized control trials that met our inclusion criteria and extracted relevant data and evaluated the methodologic quality of the studies. Of the 8 studies identified, 2 studies were crossover randomized control trials studying the effects of acute aerobic physical activity on cognitive performance. Six studies were parallel-group randomized control studies, of which only 2 had a follow-up period of longer than 6 months. All studies showed that APA had a generally positive impact on children’s cognition and psychosocial function. However, this relationship was found to be minimal in many studies and in some measures, no significant improvement was seen at all. There was no documentation of APA having any negative impact on children’s cognition and psychosocial health, even in cases where school curriculum time was reassigned from classroom teaching to aerobic physical activity. Conclusion APA is positively associated with cognition, academic achievement, behavior, and psychosocial functioning outcomes. More rigorous trials with adequate sample sizes assessing the impact of APA on

  11. Ebola: A holistic approach is required to achieve effective management and control

    PubMed Central

    Roca, Anna; Afolabi, Muhammed O.; Saidu, Yauba; Kampmann, Beate

    2015-01-01

    The current Ebola outbreak in West Africa has already caused substantial mortality and dire human and economic consequences. It continues to represent an alarming public health threat in the region and beyond and jeopardizes the provision of health care and other services in the affected countries. The scale of the epidemic has accelerated research efforts for diagnostics, treatment, and prevention galvanized through increased availability of funding. Our knowledge relating to the virus, disease pathogenesis, risk factors, dynamics of transmission, and epidemic control is increasing, and sociocultural factors have emerged as critical determinants for the success and failure of control efforts. However, there is a long way to go. In this review we summarize the current knowledge, examine the sociocultural context in West Africa, and outline priority areas for future research. PMID:25843598

  12. Achieving reliable operation of a steam turbine's automatic control and protection system

    NASA Astrophysics Data System (ADS)

    Naumov, S. A.; Naumov, A. S.; Shvetsov, D. P.; Krymskii, A. V.

    2011-01-01

    The algorithms, procedures, and modules for making expert estimates of the technical state of automatic control and protection systems for different types of turbines by means of the SPIDER mobile computerized automation system are presented. It is shown that owing to high trustworthiness with which the kind and location of hidden defects of units are determined without disassembling them, repair works can be scheduled in the optimal way and the costs for carrying them out can be reduced.

  13. Identification of Energy Efficiency Opportunities through Building Data Analysis and Achieving Energy Savings through Improved Controls

    SciTech Connect

    Katipamula, Srinivas; Taasevigen, Danny J.; Koran, Bill

    2014-09-04

    This chapter will highlight analysis techniques to identify energy efficiency opportunities to improve operations and controls. A free tool, Energy Charting and Metrics (ECAM), will be used to assist in the analysis of whole-building, sub-metered, and/or data from the building automation system (BAS). Appendix A describes the features of ECAM in more depth, and also provide instructions for downloading ECAM and all resources pertaining to using ECAM.

  14. A procedure to achieve fine control in MW processing of foods

    NASA Astrophysics Data System (ADS)

    Cuccurullo, G.; Cinquanta, L.; Sorrentino, G.

    2007-01-01

    A two-dimensional analytical model for predicting the unsteady temperature field in a cylindrical shaped body affected by spatially varying heat generation is presented. The dimensionless problem is solved analytically by using both partial solutions and the variation of parameters techniques. Having in mind industrial microwave heating for food pasteurization, the easy-to-handle solution is used to confirm the intrinsic lack of spatial uniformity of such a treatment in comparison to the traditional one. From an experimental point of view, a batch pasteurization treatment was realized to compare the effect of two different control techniques both based on IR thermography readout: the former assured a classical PID control, while the latter was based on a "shadowing" technique, consisting in covering portions of the sample which are hot enough with a mobile metallic screen. A measure of the effectiveness of the two control techniques was obtained by evaluating the thermal death curves of a strain Lactobacillus plantarum submitted to pasteurization temperatures. Preliminary results showed meaningful increases in the microwave thermal inactivation of the L. plantarum and similar significant decreases in thermal inactivation time with respect to the traditional pasteurization thermal treatment.

  15. Analysis of alternatives for insulinizing patients to achieve glycemic control and avoid accompanying risks of hypoglycemia

    PubMed Central

    GAO, JIALIN; XIONG, QIANYIN; MIAO, JUN; ZHANG, YAO; XIA, LIBING; LU, MEIQIN; ZHANG, BINHUA; CHEN, YUEPING; ZHANG, ANSU; YU, CUI; WANG, LI-ZHUO

    2015-01-01

    The aims of the present study were to explore the efficacy of glycemic control and the risks of hypoglycemia with different methods of insulin therapy, and to provide reference data for the clinical treatment of diabetes. In this retrospective study, hospitalized patients diagnosed with type 2 diabetes between March and December 2014, in the Department of Endocrinology in the First Affiliated Hospital of Wannan Medical College, were divided into three groups, including an intensive insulin analogue therapy group, a premixed insulin analogue treatment group and a premixed human insulin therapy group. The efficacy of glycemic control and the incidence of hypoglycemia were determined in each of the insulin treatment groups. Compared with the other treatment groups, the intensive insulin analogue therapy group was associated with superior blood glucose control, shorter time to reach standard insulin regimen, shorter hospitalization time, fewer fluctuations in blood glucose levels and lower insulin dosage on discharge from hospital. However, this treatment was also associated with a high risk of hypoglycemia. In conclusion, when combined with the effective prevention of hypoglycemia and appropriate nursing care (especially in hospital care), intensive insulin analogue therapy may provide the greatest benefit to patients. PMID:26137223

  16. Achieving high dependability and safety in sluice automation by using a fuzzy-logic-based control system

    SciTech Connect

    1998-07-01

    This paper describes how sluice automation was realized, achieving the customer requirements of dependability and safety. The analysis of both the managerial and technical problems has lead ENEL-PIN to develop an innovative sluice barrage control system, whose control algorithm is fuzzy-logic-based, that can be easily configured for each plant belonging to the identified sluice barrage class. APOS 1 achieves the automation requirements of dependability and safety by using a strong and continuous H/W and S/W self-testing and plant diagnosis, implementing particular techniques in order to realize a valid protection against electromagnetic interferences and climatic influences, and implementing suited command strategies to apply safety measures in case of hazardous situations. Its main tasks are to operate up to seven sluice-gates, suited for regulation, for controlling the river level near the sluices, and to perform a broadly diagnostic activity over the whole plant and on itself, to be used both on-line and for plant maintenance. APOS application software was designed in a general way for a class of plants, so that it may be configured by the plant expert personnel by means of a simple setting of some numeric parameters, during the plant installation. The core of the control system is a fuzzy-logic-based algorithm, that proved to be fast, reliable, and easily configurable to operate on different plants, because of the natural way in which the operation personnel's knowledge can be expressed. 1 APOS - Programmable Sluice Control System.

  17. Achievement of controlled resistive response of nanogapped palladium film to hydrogen

    SciTech Connect

    Zhao, M.; Wong, M. H.; Ong, C. W.

    2015-07-20

    Palladium (Pd) film containing nanogaps of well controlled dimension was fabricated on a Si wafer having a high-aspect-ratio micropillar. The Pd film was arranged to experience hydrogen (H{sub 2})-induced volume expansion. (i) If the nanogap is kept open, its width is narrowed down. A discharge current was generated to give a strong, fast, and repeatable on-off type resistive switching response. (ii) If the nanogap is closed, the cross section of the conduction path varies to give continuous H{sub 2}-concentration dependent resistive response. The influence of stresses and related physical mechanisms are discussed.

  18. Terrestrial rabies control in the European Union: historical achievements and challenges ahead.

    PubMed

    Müller, Thomas; Freuling, Conrad Martin; Wysocki, Patrick; Roumiantzeff, Micha; Freney, Jean; Mettenleiter, Thomas Christoph; Vos, Adriaan

    2015-01-01

    Due to the implementation of oral rabies vaccination (ORV) programmes, the European Union (EU) is becoming progressively free of red fox (Vulpes vulpes)-mediated rabies. Over the past three decades, the incidence of rabies had decreased substantially and vast areas of Western and Central Europe have been freed from rabies using this method of controlling an infectious disease in wildlife. Since rabies control is a top priority in the EU, the disease is expected to be eliminated from the animal source in the near future. While responsible authorities may consider the mission of eliminating fox rabies from the EU almost accomplished, there are still issues to be dealt with and challenges to be met that have not yet been in the focus of attention, but could jeopardise the ultimate goal. Among them are increasing illegal movements of animals, maintaining funding support for vaccination campaigns, devising alternative vaccine strategies in neighbouring Eastern European countries and the expanding distribution range of several potential rabies reservoir species in Europe. PMID:25466578

  19. A quantitative integrated assessment of pollution prevention achieved by integrated pollution prevention control licensing.

    PubMed

    Styles, David; O'Brien, Kieran; Jones, Michael B

    2009-11-01

    This paper presents an innovative, quantitative assessment of pollution avoidance attributable to environmental regulation enforced through integrated licensing, using Ireland's pharmaceutical-manufacturing sector as a case study. Emissions data reported by pharmaceutical installations were aggregated into a pollution trend using an Environmental Emissions Index (EEI) based on Lifecycle Assessment methodologies. Complete sectoral emissions data from 2001 to 2007 were extrapolated back to 1995, based on available data. Production volume data were used to derive a sectoral production index, and determine 'no-improvement' emission trends, whilst questionnaire responses from 20 industry representatives were used to quantify the contribution of integrated licensing to emission avoidance relative to these trends. Between 2001 and 2007, there was a 40% absolute reduction in direct pollution from 27 core installations, and 45% pollution avoidance relative to hypothetical 'no-improvement' pollution. It was estimated that environmental regulation avoided 20% of 'no-improvement' pollution, in addition to 25% avoidance under business-as-usual. For specific emissions, avoidance ranged from 14% and 30 kt a(-1) for CO(2) to 88% and 598 t a(-1) for SO(x). Between 1995 and 2007, there was a 59% absolute reduction in direct pollution, and 76% pollution avoidance. Pollution avoidance was dominated by reductions in emissions of VOCs, SO(x) and NO(x) to air, and emissions of heavy metals to water. Pollution avoidance of 35% was attributed to integrated licensing, ranging from between 8% and 2.9 t a(-1) for phosphorus emissions to water to 49% and 3143 t a(-1) for SO(x) emissions to air. Environmental regulation enforced through integrated licensing has been the major driver of substantial pollution avoidance achieved by Ireland's pharmaceutical sector - through emission limit values associated with Best Available Techniques, emissions monitoring and reporting requirements, and

  20. Student-Friendly Precision Pendulum.

    ERIC Educational Resources Information Center

    Peters, Randall D.

    1999-01-01

    Provides information to help students easily measure gravitational field strength to a few parts in 10,000, a degree of precision 1-2 orders of magnitude better than can be achieved with the simple pendulum. (CCM)

  1. The Prefrontal Cortex Achieves Inhibitory Control by Facilitating Subcortical Motor Pathway Connectivity

    PubMed Central

    Hughes, Laura E.; Anderson, Michael C.; Rowe, James B.

    2015-01-01

    Communication between the prefrontal cortex and subcortical nuclei underpins the control and inhibition of behavior. However, the interactions in such pathways remain controversial. Using a stop-signal response inhibition task and functional imaging with analysis of effective connectivity, we show that the lateral prefrontal cortex influences the strength of communication between regions in the frontostriatal motor system. We compared 20 generative models that represented alternative interactions between the inferior frontal gyrus, presupplementary motor area (preSMA), subthalamic nucleus (STN), and primary motor cortex during response inhibition. Bayesian model selection revealed that during successful response inhibition, the inferior frontal gyrus modulates an excitatory influence of the preSMA on the STN, thereby amplifying the downstream polysynaptic inhibition from the STN to the motor cortex. Critically, the strength of the interaction between preSMA and STN, and the degree of modulation by the inferior frontal gyrus, predicted individual differences in participants' stopping performance (stop-signal reaction time). We then used diffusion-weighted imaging with tractography to assess white matter structure in the pathways connecting these three regions. The mean diffusivity in tracts between preSMA and the STN, and between the inferior frontal gyrus and STN, also predicted individual differences in stopping efficiency. Finally, we found that white matter structure in the tract between preSMA and STN correlated with effective connectivity of the same pathway, providing important cross-modal validation of the effective connectivity measures. Together, the results demonstrate the network dynamics and modulatory role of the prefrontal cortex that underpin individual differences in inhibitory control. PMID:25589771

  2. Photocurrent enhancement of n-type Cu2O electrodes achieved by controlling dendritic branching growth.

    PubMed

    McShane, Colleen M; Choi, Kyoung-Shin

    2009-02-25

    Cu(2)O electrodes composed of dendritic crystals were produced electrochemically using a slightly acidic medium (pH 4.9) containing acetate buffer. The buffer played a key role for stabilizing dendritic branching growth as a pH drop during the synthesis prevents formation of morphologically unstable branches and promotes faceted growth. Dendritic branching growth enabled facile coverage of the substrate with Cu(2)O while avoiding growth of a thicker Cu(2)O layer and increasing surface areas. The resulting electrodes showed n-type behavior by generating anodic photocurrent without applying an external bias (zero-bias photocurrent under short-circuit condition) in an Ar-purged 0.02 M K(2)SO(4) solution. The zero-bias photocurrent of crystalline dendritic electrodes was significantly higher than that of the electrodes containing micrometer-size faceted crystals deposited without buffer. In order to enhance photocurrent further a strategy of improving charge-transport properties by increasing dendritic crystal domain size was investigated. Systematic changes in nucleation density and size of the dendritic Cu(2)O crystals were achieved by altering the deposition potential, Cu(2+) concentration, and acetate concentration. Increasing dendritic crystal size consistently resulted in the improvement of photocurrent regardless of the method used to regulate crystal size. The electrode composed of dendritic crystals with the lateral dimension of ca. 12000 microm(2) showed more than 20 times higher zero-bias photocurrent than that composed of dendritic crystals with the lateral dimension of ca. 100 microm(2). The n-type nature of the Cu(2)O electrodes prepared by this study were confirmed by linear sweep voltammetry with chopped light and capacitance measurements (i.e., Mott-Schottky plots). The flatband potential in a 0.2 M K(2)SO(4) solution (pH 6) was estimated to be -0.78 vs Ag/AgCl reference electrode. The IPCE measured without applying an external bias was approximately 1

  3. [What glycemic control can be achieved in diabetic children and adolescents to avoid complications? Personal experience].

    PubMed

    Dorchy, H

    2006-01-01

    The principal aims of therapeutic management of the child, adolescent and adult with type 1 diabetes are to allow good quality of life and to avoid long-term complications by maintaining blood glucose concentrations close to the normal range and an HbA1c level under 7%. The number of daily insulin injections, 2 or > or =4 or pumps, by itself does not necessarily give better results, but the 4-injection regimen allows greater freedom, taking into account that the proper insulin adjustment is difficult before adolescence. Successful glycaemic control in young patients depends mainly on the quality and intensity of diabetes education. Any dogmatism must be avoided. Dietary recommendations issued over the last few years are the same for diabetic and nondiabetic individuals in order to avoid degenerative diseases. In the twice-daily injection regimen, the allocation of carbohydrates throughout the day is essential. Due to their pharmakokinetic characteristics, fast-acting and long-acting insulin analogues have specific indications in both the twice-daily injection regimen and the basal-bolus insulin therapy. They improve quality of life, without necessarily reducing HbA1c. In the two daily insulin injection regimen, fast-acting analogues are very useful to rapidly correct hyperglycaemia, to allow sleeping in and eating something sweet. In the basal-bolus regimen, long-acting analogues reduce nocturnal hypoglycaemias and improve fasting blood glucose. Clinical studies, conducted since the 1970s by our team, have demonstrated that screening for subclinical retinopathy (fluorescein angiography), neuropathy (conduction velocities), nephropathy (microalbuminuria), should be started at puberty and at least 3 years after the diagnosis of diabetes. The goal is to detect early abnormalities responsible for subclinical disorders that can be reversed by improved metabolic control, thus preventing the occurrence of irreversible potentially incapacitating lesions. This motivates

  4. Tools and Strategies for Malaria Control and Elimination: What Do We Need to Achieve a Grand Convergence in Malaria?

    PubMed Central

    Hemingway, Janet; Shretta, Rima; Wells, Timothy N. C.; Bell, David; Djimdé, Abdoulaye A.; Achee, Nicole; Qi, Gao

    2016-01-01

    Progress made in malaria control during the past decade has prompted increasing global dialogue on malaria elimination and eradication. The product development pipeline for malaria has never been stronger, with promising new tools to detect, treat, and prevent malaria, including innovative diagnostics, medicines, vaccines, vector control products, and improved mechanisms for surveillance and response. There are at least 25 projects in the global malaria vaccine pipeline, as well as 47 medicines and 13 vector control products. In addition, there are several next-generation diagnostic tools and reference methods currently in development, with many expected to be introduced in the next decade. The development and adoption of these tools, bolstered by strategies that ensure rapid uptake in target populations, intensified mechanisms for information management, surveillance, and response, and continued financial and political commitment are all essential to achieving global eradication. PMID:26934361

  5. Tools and Strategies for Malaria Control and Elimination: What Do We Need to Achieve a Grand Convergence in Malaria?

    PubMed

    Hemingway, Janet; Shretta, Rima; Wells, Timothy N C; Bell, David; Djimdé, Abdoulaye A; Achee, Nicole; Qi, Gao

    2016-03-01

    Progress made in malaria control during the past decade has prompted increasing global dialogue on malaria elimination and eradication. The product development pipeline for malaria has never been stronger, with promising new tools to detect, treat, and prevent malaria, including innovative diagnostics, medicines, vaccines, vector control products, and improved mechanisms for surveillance and response. There are at least 25 projects in the global malaria vaccine pipeline, as well as 47 medicines and 13 vector control products. In addition, there are several next-generation diagnostic tools and reference methods currently in development, with many expected to be introduced in the next decade. The development and adoption of these tools, bolstered by strategies that ensure rapid uptake in target populations, intensified mechanisms for information management, surveillance, and response, and continued financial and political commitment are all essential to achieving global eradication. PMID:26934361

  6. Strategies To Achieve Control over the Surface Ratio of Two Different Components on Modified Electrodes Using Aryldiazonium Salts.

    PubMed

    Jiang, Cheng; Alam, Muhammad Tanzirul; Parker, Stephen G; Darwish, Nadim; Gooding, J Justin

    2016-03-15

    Controlling the composition of an interface is very important in tuning the chemical and physical properties of a surface in many applications including biosensors, biomaterials, and chemical catalysis. Frequently, this requires one molecular component to a minor component in a mixed layer. Such subtle control of composition has been difficult to achieve using aryldiazonium salts. Herein, aryldiazonium salts of carboxyphenyl (CP) and phenylphosphorylcholine (PPC), generated in situ from their corresponding anilines, are electrografted to form molecular platform that are available for further functionalization. These two components are chosen because CP provides a convenient functionality for further coupling of biorecognition species while PPC offers resistance to nonspecific adsorption of proteins to the surface. Mixed layers of CP and PPC were prepared by grafting them either simultaneously or consecutively. The latter strategy allows an interface to be developed in a controlled way where one component is at levels of less than 1% of the total layer. PMID:26901641

  7. Herbicides as Weed Control Agents: State of the Art: II. Recent Achievements[C

    PubMed Central

    Kraehmer, Hansjoerg; van Almsick, Andreas; Beffa, Roland; Dietrich, Hansjoerg; Eckes, Peter; Hacker, Erwin; Hain, Ruediger; Strek, Harry John; Stuebler, Hermann; Willms, Lothar

    2014-01-01

    In response to changing market dynamics, the discovery of new herbicides has declined significantly over the past few decades and has only seen a modest upsurge in recent years. Nevertheless, the few introductions have proven to be interesting and have brought useful innovation to the market. In addition, herbicide-tolerant or herbicide-resistant crop technologies have allowed the use of existing nonselective herbicides to be extended into crops. An increasing and now major challenge is being posed by the inexorable increase in biotypes of weeds that are resistant to herbicides. This problem is now at a level that threatens future agricultural productivity and needs to be better understood. If herbicides are to remain sustainable, then it is a must that we adopt diversity in crop rotation and herbicide use as well as increase the use of nonchemical measures to control weeds. Nevertheless, despite the difficulties posed by resistant weeds and increased regulatory hurdles, new screening tools promise to provide an upsurge of potential herbicide leads. Our industry urgently needs to supply agriculture with new, effective resistance-breaking herbicides along with strategies to sustain their utility. PMID:25104721

  8. Herbicides as weed control agents: state of the art: II. Recent achievements.

    PubMed

    Kraehmer, Hansjoerg; van Almsick, Andreas; Beffa, Roland; Dietrich, Hansjoerg; Eckes, Peter; Hacker, Erwin; Hain, Ruediger; Strek, Harry John; Stuebler, Hermann; Willms, Lothar

    2014-11-01

    In response to changing market dynamics, the discovery of new herbicides has declined significantly over the past few decades and has only seen a modest upsurge in recent years. Nevertheless, the few introductions have proven to be interesting and have brought useful innovation to the market. In addition, herbicide-tolerant or herbicide-resistant crop technologies have allowed the use of existing nonselective herbicides to be extended into crops. An increasing and now major challenge is being posed by the inexorable increase in biotypes of weeds that are resistant to herbicides. This problem is now at a level that threatens future agricultural productivity and needs to be better understood. If herbicides are to remain sustainable, then it is a must that we adopt diversity in crop rotation and herbicide use as well as increase the use of nonchemical measures to control weeds. Nevertheless, despite the difficulties posed by resistant weeds and increased regulatory hurdles, new screening tools promise to provide an upsurge of potential herbicide leads. Our industry urgently needs to supply agriculture with new, effective resistance-breaking herbicides along with strategies to sustain their utility. PMID:25104721

  9. Population control of an overabundant species achieved through consecutive anthropogenic perturbations.

    PubMed

    Payo-Payo, Ana; Oro, Daniel; Igual, José Manuel; Jover, Lluis; Sanpera, Carolina; Tavecchia, Giacomo

    2015-12-01

    The control of overabundant vertebrates is often problematic. Much work has focused on population-level responses and overabundance due to anthropogenic subsidies. However, far less work has been directed at investigating responses following the removal of subsidies. We investigate the consequences of two consecutive perturbations, the closure of a landfill and an inadvertent poisoning event, on the trophic ecology (δ13C, δ15N, and δ34S), survival, and population size of an overabundant generalist seabird species, the Yellow-legged Gull (Larus michahellis). We expected that the landfill closure would cause a strong dietary shift and the inadvertent poisoning a decrease in gull population size. As a long-lived species, we also anticipated adult survival to be buffered against the decrease in food availability but not against the inadvertent poisoning event. Stable isotope analysis confirmed the dietary shift towards marine resources after the disappearance of the landfill. Although the survival model was inconclusive, it did suggest that the perturbations had a negative effect on survival, which was followed by a recovery back to average values. Food limitation likely triggered dispersal to other populations, while poisoning may have increased mortality; these two processes were likely responsible for the large fall in population size that occurred after the two consecutive perturbations. Life-history theory suggests that perturbations may encourage species to halt existing breeding investment in order to ensure future survival. However, under strong perturbation pulses the resilience threshold might be surpassed and changes in population density can arise. Consecutive perturbations may effectively manage overabundant species. PMID:26910951

  10. Gaining control: changing relations between executive control and processing speed and their relevance for mathematics achievement over course of the preschool period

    PubMed Central

    Clark, Caron A. C.; Nelson, Jennifer Mize; Garza, John; Sheffield, Tiffany D.; Wiebe, Sandra A.; Espy, Kimberly Andrews

    2014-01-01

    Early executive control (EC) predicts a range of academic outcomes and shows particularly strong associations with children's mathematics achievement. Nonetheless, a major challenge for EC research lies in distinguishing EC from related cognitive constructs that also are linked to achievement outcomes. Developmental cascade models suggest that children's information processing speed is a driving mechanism in cognitive development that supports gains in working memory, inhibitory control and associated cognitive abilities. Accordingly, individual differences in early executive task performance and their relation to mathematics may reflect, at least in part, underlying variation in children's processing speed. The aims of this study were to: (1) examine the degree of overlap between EC and processing speed at different preschool age points; and (2) determine whether EC uniquely predicts children's mathematics achievement after accounting for individual differences in processing speed. As part of a longitudinal, cohort-sequential study, 388 children (50% boys; 44% from low income households) completed the same battery of EC tasks at ages 3, 3.75, 4.5, and 5.25 years. Several of the tasks incorporated baseline speeded naming conditions with minimal EC demands. Multidimensional latent models were used to isolate the variance in executive task performance that did not overlap with baseline processing speed, covarying for child language proficiency. Models for separate age points showed that, while EC did not form a coherent latent factor independent of processing speed at age 3 years, it did emerge as a distinct factor by age 5.25. Although EC at age 3 showed no distinct relation with mathematics achievement independent of processing speed, EC at ages 3.75, 4.5, and 5.25 showed independent, prospective links with mathematics achievement. Findings suggest that EC and processing speed are tightly intertwined in early childhood. As EC becomes progressively decoupled from

  11. A Pilot Study on the Congruency of Locus of Control and Field Dependence as Related to Self-Esteem and Academic Achievement.

    ERIC Educational Resources Information Center

    Garner, C. William; Cole, Ernest G.

    A pilot study was conducted at two middle schools to investigate the relationship among student locus of control, field dependency, self-esteem, and achievement. A relationship between self-esteem and achievement has already been identified by research; another variable considered as a possible effect on a person's predisposition to achieve was…

  12. Integral sliding mode controller for precise manoeuvring of autonomous underwater vehicle in the presence of unknown environmental disturbances

    NASA Astrophysics Data System (ADS)

    Kim, Minsung; Joe, Hangil; Kim, Jinwhan; Yu, Son-cheol

    2015-10-01

    We propose an integral sliding mode controller (ISMC) to stabilse an autonomous underwater vehicle (AUV) which is subject to modelling errors and often suffers from unknown environmental disturbances. The ISMC is effective in compensating for the uncertainties in the hydrodynamic and hydrostatic parameters of the vehicle and rejecting the unpredictable disturbance effects due to ocean waves, tides and currents. The ISMC is comprised of an equivalent controller and a switching controller to suppress the parameter uncertainties and external disturbances, and its closed-loop system is exponentially stable. Numerical simulations were performed to validate the proposed control approach, and experimental tests using Cyclops AUV were carried out to demonstrate its practical feasibility.

  13. Precise Method for Investigation of Lissajous Generalized Figures

    ERIC Educational Resources Information Center

    Bednarek, Stanislaw

    2014-01-01

    This article describes the Lissajous generalized figure and the original instrument for its investigation. Two specially prepared electrodynamic loudspeakers--a horizontal and a vertical--cause oscillations in two mirrors. It is possible to precisely control the motion of the mirrors, achieve a high frequency of oscillation and investigate…

  14. Exercise Improves Executive Function and Achievement and Alters Brain Activation in Overweight Children: A Randomized Controlled Trial

    PubMed Central

    Davis, Catherine L.; Tomporowski, Phillip D.; McDowell, Jennifer E.; Austin, Benjamin P.; Miller, Patricia H.; Yanasak, Nathan E.; Allison, Jerry D.; Naglieri, Jack A.

    2010-01-01

    Objective This experiment tested the hypothesis that exercise would improve executive function. Design Sedentary, overweight 7- to 11-year-old children (N = 171, 56% female, 61% Black, M ± SD age 9.3 ± 1.0 yrs, body mass index (BMI) 26 ± 4.6 kg/m2, BMI z-score 2.1 ± 0.4) were randomized to 13 ± 1.6 weeks of an exercise program (20 or 40 minutes/day), or a control condition. Main outcome measures Blinded, standardized psychological evaluations (Cognitive Assessment System and Woodcock-Johnson Tests of Achievement III) assessed cognition and academic achievement. Functional magnetic resonance imaging measured brain activity during executive function tasks. Results Intent to treat analysis revealed dose response benefits of exercise on executive function and mathematics achievement. Preliminary evidence of increased bilateral prefrontal cortex activity and reduced bilateral posterior parietal cortex activity due to exercise was also observed. Conclusion Consistent with results obtained in older adults, a specific improvement on executive function and brain activation changes due to exercise were observed. The cognitive and achievement results add evidence of dose response, and extend experimental evidence into childhood. This study provides information on an educational outcome. Besides its importance for maintaining weight and reducing health risks during a childhood obesity epidemic, physical activity may prove to be a simple, important method of enhancing aspects of children’s mental functioning that are central to cognitive development. This information may persuade educators to implement vigorous physical activity. PMID:21299297

  15. A Simple Way to Achieve Legible and Local Controllable Patterning for Polymers Based on a Near-Infrared Pulsed Laser.

    PubMed

    Zhang, Jihai; Zhou, Tao; Wen, Liang; Zhao, Jing; Zhang, Aiming

    2016-01-27

    This study developed a simple way to achieve legible and local controllable patterning for polymers based on a near-infrared (NIR) pulsed laser. The polycarbonate-coated nano antimony-doped tin oxide (nano ATO) was designed as a core-shell structure that was tailored to be responsive to a 1064 nm NIR laser. The globular morphology of polycarbonate-coated nano ATO with a diameter of around 2-3 μm was observed by scanning electron microscopy and transmission electron microscopy. This core-shell structure combined the excellent photothermal conversion efficiency of nano ATO and the high char (carbon) residue of polycarbonate. The X-ray photoelectron spectroscopy results of a polymer-patterning plate after laser irradiation demonstrated that, through local controlled photochromism, the well-defined legible patterns can be fabricated on the polymer surfaces contribute to the synergistic effect consisting of polycarbonate carbonization and nano ATO photothermal conversion. Furthermore, polymers doped with a minimal content of polycarbonate-coated nano ATO can achieve a remarkable patterning effect. This novel laser-patterning approach will have wide promising applications in the field of polymer NIR pulsed-laser patterning. PMID:26717082

  16. Precision Heating Process

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A heat sealing process was developed by SEBRA based on technology that originated in work with NASA's Jet Propulsion Laboratory. The project involved connecting and transferring blood and fluids between sterile plastic containers while maintaining a closed system. SEBRA markets the PIRF Process to manufacturers of medical catheters. It is a precisely controlled method of heating thermoplastic materials in a mold to form or weld catheters and other products. The process offers advantages in fast, precise welding or shape forming of catheters as well as applications in a variety of other industries.

  17. A Further Examination of the Distinction between Dependency-Oriented and Achievement-Oriented Parental Psychological Control: Psychometric Properties of the DAPCS with French-Speaking Late Adolescents

    ERIC Educational Resources Information Center

    Mantzouranis, Gregory; Zimmermann, Gregoire; Mahaim, Elodie Biermann; Favez, Nicolas

    2012-01-01

    Psychological control refers to parental behaviors that intrude on the psychological and emotional development of the child. In 2010, Soenens et al. proposed a distinction between two domain-specific expressions of psychological control, that is, Dependency-oriented Psychological Control (DPC) and Achievement-oriented Psychological Control (APC).…

  18. Methods of precisely estimating the jacket pressure coefficient of controlled-clearance piston-cylinders at pressures up to 1 GPa

    NASA Astrophysics Data System (ADS)

    Kajikawa, Hiroaki; Ide, Kazunori; Kobata, Tokihiko

    2011-10-01

    Deformational characteristics of a controlled-clearance piston-cylinder (CCPC) have been evaluated to precisely estimate the pressure dependence of its effective area. Among the experimentally accessible characteristics, the jacket pressure coefficient d, which denotes the relative change in the effective area due to applied jacket pressure pj, is examined in this paper. Two methods for precisely determining d at pressures up to 1 GPa are proposed. One is a comparative method that uses a set of a pressure balance and a multiplier as the tare gauge. The other is a new method that uses precise pressure transducers as monitoring devices. Both pj and weights loaded on the CCPC are changed so that the pressure generated by the CCPC remains constant, which is monitored by the transducers. d is estimated by the relative change in the weights loaded on the CCPC itself. Using the two methods, d for a 1 MPa kg-1 CCPC is measured at pressures up to 1 GPa. At each system pressure, d obtained by each method is approximated by a linear function of pj. The consistency of the fit values of d by the two methods is confirmed. The method using pressure transducers as monitoring devices is advantageous in terms of efficiency and operability especially at higher pressures.

  19. Improving the precision matrix for precision cosmology

    NASA Astrophysics Data System (ADS)

    Paz, Dante J.; Sánchez, Ariel G.

    2015-12-01

    The estimation of cosmological constraints from observations of the large-scale structure of the Universe, such as the power spectrum or the correlation function, requires the knowledge of the inverse of the associated covariance matrix, namely the precision matrix, Ψ . In most analyses, Ψ is estimated from a limited set of mock catalogues. Depending on how many mocks are used, this estimation has an associated error which must be propagated into the final cosmological constraints. For future surveys such as Euclid and Dark Energy Spectroscopic Instrument, the control of this additional uncertainty requires a prohibitively large number of mock catalogues. In this work, we test a novel technique for the estimation of the precision matrix, the covariance tapering method, in the context of baryon acoustic oscillation measurements. Even though this technique was originally devised as a way to speed up maximum likelihood estimations, our results show that it also reduces the impact of noisy precision matrix estimates on the derived confidence intervals, without introducing biases on the target parameters. The application of this technique can help future surveys to reach their true constraining power using a significantly smaller number of mock catalogues.

  20. Five degree-of-freedom control of an ultra-precision magnetically-suspended linear bearing. Ph.D. Thesis - MIT

    NASA Technical Reports Server (NTRS)

    Trumper, David L.; Slocum, A. H.

    1991-01-01

    The authors constructed a high precision linear bearing. A 10.7 kg platen measuring 125 mm by 125 mm by 350 mm is suspended and controlled in five degrees of freedom by seven electromagnets. The position of the platen is measured by five capacitive probes which have nanometer resolution. The suspension acts as a linear bearing, allowing linear travel of 50 mm in the sixth degree of freedom. In the laboratory, this bearing system has demonstrated position stability of 5 nm peak-to-peak. This is believed to be the highest position stability yet demonstrated in a magnetic suspension system. Performance at this level confirms that magnetic suspensions can address motion control requirements at the nanometer level. The experimental effort associated with this linear bearing system is described. Major topics are the development of models for the suspension, implementation of control algorithms, and measurement of the actual bearing performance. Suggestions for the future improvement of the bearing system are given.

  1. Some data processing requirements for precision Nap-Of-the-Earth (NOE) guidance and control of rotorcraft

    NASA Technical Reports Server (NTRS)

    Clement, Warren F.; Mcruer, Duane T.; Magdeleno, Raymond E.

    1987-01-01

    Nap-Of-the-Earth (NOE) flight in a conventional helicopter is extremely taxing for two pilots under visual conditions. Developing a single pilot all-weather NOE capability will require a fully automatic NOE navigation and flight control capability for which innovative guidance and control concepts were examined. Constrained time-optimality provides a validated criterion for automatically controlled NOE maneuvers if the pilot is to have confidence in the automated maneuvering technique. A second focus was to organize the storage and real-time updating of NOE terrain profiles and obstacles in course-oriented coordinates indexed to the mission flight plan. A method is presented for using pre-flight geodetic parameter identification to establish guidance commands for planned flight profiles and alternates. A method is then suggested for interpolating this guidance command information with the aid of forward and side looking sensors within the resolution of the stored data base, enriching the data content with real-time display, guidance, and control purposes. A third focus defined a class of automatic anticipative guidance algorithms and necessary data preview requirements to follow the vertical, lateral, and longitudinal guidance commands dictated by the updated flight profiles and to address the effects of processing delays in digital guidance and control system candidates. The results of this three-fold research effort offer promising alternatives designed to gain pilot acceptance for automatic guidance and control of rotorcraft in NOE operations.

  2. Dual control system - A novel scaffolding architecture of an inducible regulatory device for the precise regulation of gene expression.

    PubMed

    Horbal, L; Luzhetskyy, A

    2016-09-01

    Here, we present a novel scaffolding architecture of an inducible regulatory device. This dual control system is completely silent in the off stage and is coupled to the regulation of gene expression at both the transcriptional and translational levels. This system also functions as an AND gate. We demonstrated the effectiveness of the cumate-riboswitch dual control system for the control of pamamycin production in Streptomyces albus. Placing the cre recombinase gene under the control of this system permitted the construction of synthetic devices with non-volatile memory that sense the signal and respond by altering DNA at the chromosomal level, thereby producing changes that are heritable. In addition, we present a library of synthetic inducible promoters based on the previously described cumate switch. With only one inducer and different promoters, we demonstrate that simultaneous modulation of the expression of several genes to different levels in various operons is possible. Because all modules of the AND gates are functional in bacteria other than Streptomyces, we anticipate that these regulatory devices can be used to control gene expression in other Actinobacteria. The features described in this study make these systems promising tools for metabolic engineering and biotechnology in Actinobacteria. PMID:27040671

  3. The Circumstellar Imaging Telescope image motion compensation system - Ultra-precise control on the Space Station platform

    NASA Technical Reports Server (NTRS)

    Sevaston, G. E.; Socha, M. M.; Eisenman, A.

    1989-01-01

    The Circumstellar Imaging Telescope (CIT) is a 1.9 m visible wavelength Cassegrain instrument whose primary mission is to locate extra-solar planets by direct imaging. The current reference concept calls for it to be deployed as a Space Station attached payload some time in the late 1990s. Mission and signal processing demands impose the following attitude control requirements: pointing accuracy - 250 nrad RMS, pointing stability - 50 nrad RMS over 30 minutes, roll accuracy - 1 mrad RMS, roll stability 1 mrad RMS over 30 minutes. This paper reports on the results of a recent design study in which it was determined that these requirements can be met on the Space Station by a three tiered control system consisting of a two degree of freedom mechanical gimbal for course pointing, a magnetically suspended roll bearing for roll accommodation, translational isolation and intermediate pointing control, and articulation of the secondary mirror for fine pointing.

  4. Improved efficiency and precise temperature control of low-frequency induction-heating pure iron vapor source on ECR ion source

    SciTech Connect

    Kato, Y.; Takenaka, T.; Yano, K.; Kiriyama, R.; Kurisu, Y.; Nozaki, D.; Muramatsu, M.; Kitagawa, A.; Uchida, T.; Yoshida, Y.; Sato, F.; Iida, T.

    2012-11-06

    Multiply charged ions to be used prospectively are produced from solid pure material in an electron cyclotron resonance ion source (ECRIS). Recently a pure iron source is also required for the production of caged iron ions in the fullerene in order to control cells in vivo in bio-nano science and technology. We adopt directly heating iron rod by induction heating (IH) because it has non-contact with insulated materials which are impurity gas sources. We choose molybdenum wire for the IH coils because it doesn't need water cooling. To improve power efficiency and temperature control, we propose to the new circuit without previously using the serial and parallel dummy coils (SPD) for matching and safety. We made the circuit consisted of inductively coupled coils which are thin-flat and helix shape, and which insulates the IH power source from the evaporator. This coupling coils circuit, i.e. insulated induction heating coil transformer (IHCT), can be move mechanically. The secondary current can be adjusted precisely and continuously. Heating efficiency by using the IHCT is much higher than those of previous experiments by using the SPD, because leakage flux is decreased and matching is improved simultaneously. We are able to adjust the temperature in heating the vapor source around melting point. And then the vapor pressure can be controlled precisely by using the IHCT. We can control {+-}10K around 1500 Degree-Sign C by this method, and also recognize to controlling iron vapor flux experimentally in the extreme low pressures. Now we come into next stage of developing induction heating vapor source for materials with furthermore high temperature melting points above 2000K with the IHCT, and then apply it in our ECRIS.

  5. Precision synchrotron radiation detectors

    SciTech Connect

    Levi, M.; Rouse, F.; Butler, J.; Jung, C.K.; Lateur, M.; Nash, J.; Tinsman, J.; Wormser, G.; Gomez, J.J.; Kent, J.

    1989-03-01

    Precision detectors to measure synchrotron radiation beam positions have been designed and installed as part of beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 /mu/m on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in the measurement of SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely-aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy. Also, detectors of synchrotron radiation using the charge developed by the ejection of Compton-recoil electrons from an array of fine wires are being developed. 4 refs., 5 figs., 1 tab.

  6. A novel approach for precisely controlled multiple cell patterning in microfluidic chips by inkjet printing and the detection of drug metabolism and diffusion.

    PubMed

    Zhang, Jie; Chen, Fengming; He, Ziyi; Ma, Yuan; Uchiyama, Katsumi; Lin, Jin-Ming

    2016-05-10

    In this work we report the use of inkjet printing as a precise and convenient means for microscale cell patterning in microfluidic chips followed by cell co-culture, stimulation and analysis. A self-made inkjet printing device was manufactured with adjustable parameters, which was capable of multiple cell printing within biocompatible materials. Sodium alginate was used as a printing matrix for cell encapsulation, and precisely distributed cell arrays on glass slides were obtained by accurate software controlled printing. By covering a PDMS layer with the corresponding microchannels onto the cell array substrate and subsequently injecting an ion cross-linking reagent, the cells containing alginate arrays gelated immediately and were immobilized on the bottom of the microchip, which could be utilized for cell culture and analysis. HepG2 cells and U251 cells were successfully co-patterned in the microchip and used for drug metabolism and diffusion experiment to imitate the in vivo situation, as a means to ascertain the capability of the system for precise microscale cell patterning in a microchip. The prodrug tegafur was metabolized by HepG2 cells into the active anticancer compound 5-fluorouracil and this produced an adverse gradient effect on U251 cells according to the distance from the HepG2 cells. The developed approach presented a feasible way to integrate inkjet cell printing and microfluidic chips for the first time, which is proved to be capable of spatially controlled printing of multiple kinds of cells into a microchip for cell culture, stimulation and analysis, which could be applied to tissue engineering, drug testing and related areas. We envision that the approach will help significantly increase the cell patterning efficacy in microfluidic chips as well as reduce the extent of laborious experimental work. PMID:27045202

  7. A novel triple-actuating mechanism of an active air mount for vibration control of precision manufacturing machines: experimental work

    NASA Astrophysics Data System (ADS)

    Kim, Hyung-Tae; Kim, Cheol-Ho; Choi, Seung-Bok; Moon, Seok-Jun; Song, Won-Gil

    2014-07-01

    With the goal of vibration control and isolation in a clean room, we propose a new type of air mount which consists of pneumatic, electromagnetic (EM), and magnetorheological (MR) actuators. The air mount is installed below a semiconductor manufacturing machine to reduce the adverse effects caused by unwanted vibration. The proposed mechanism integrates the forces in a parallel connection of the three actuators. The MR part is designed to operate in an air spring in which the EM part is installed. The control logic is developed with a classical method and a switching mode to avoid operational mismatch among the forces developed. Based on extended microprocessors, a portable, embedded controller is installed to execute both nonlinear logic and digital communication with the peripherals. The pneumatic forces constantly support the heavy weight of an upper structure and maintain the level of the air mount. The MR damper handles the transient response, while the EM controller reduces the resonance response, which is switched mutually with a threshold. Vibration is detected by laser displacement sensors which have submicron resolution. The impact test results of three tons load weight demonstrate practical feasibility by showing that the proposed triple-actuating mechanism can reduce the transient response as well as the resonance in the air mount, resulting in accurate motion of the semiconductor manufacturing machine.

  8. Precision asteroseismology of the pulsating white dwarf GD 1212 using a two-wheel-controlled Kepler spacecraft

    SciTech Connect

    Hermes, J. J.; Charpinet, S.; Barclay, Thomas; Mullally, Fergal; Huber, Daniel; Still, Martin; Howell, Steve B.; Caldwell, Douglas A.; Haas, Michael R.; Bryson, Stephen T.; Pakštienė, E.; Kawaler, Steven D.; Bloemen, S.; Castanheira, Barbara G.; Winget, D. E.; Montgomery, M. H.; Van Grootel, V.

    2014-07-01

    We present a preliminary analysis of the cool pulsating white dwarf (WD) GD 1212, enabled by more than 11.5 days of space-based photometry obtained during an engineering test of the two-reaction-wheel-controlled Kepler spacecraft. We detect at least 19 independent pulsation modes, ranging from 828.2-1220.8 s, and at least 17 nonlinear combination frequencies of those independent pulsations. Our longest uninterrupted light curve, 9.0 days in length, evidences coherent difference frequencies at periods inaccessible from the ground, up to 14.5 hr, the longest-period signals ever detected in a pulsating WD. These results mark some of the first science to come from a two-wheel-controlled Kepler spacecraft, proving the capability for unprecedented discoveries afforded by extending Kepler observations to the ecliptic.

  9. Precise-Conductance Valve Insert

    NASA Technical Reports Server (NTRS)

    Outlaw, R. A.; Hoyt, R. F.

    1986-01-01

    Valve modification provides two operating modes fully open and small, precise leak. Copper insert with radially oriented holes allows small, controllable, precise effusion rate when valve closed or nearly unobstructed flow when valve open. Numerous applications in surface physics, vacuum physics, materials science, gas kinetics, thin films, and other areas of research requiring measured flows of gas into or out of system.

  10. State of the Field: Extreme Precision Radial Velocities

    NASA Astrophysics Data System (ADS)

    Fischer, Debra A.; Anglada-Escude, Guillem; Arriagada, Pamela; Baluev, Roman V.; Bean, Jacob L.; Bouchy, Francois; Buchhave, Lars A.; Carroll, Thorsten; Chakraborty, Abhijit; Crepp, Justin R.; Dawson, Rebekah I.; Diddams, Scott A.; Dumusque, Xavier; Eastman, Jason D.; Endl, Michael; Figueira, Pedro; Ford, Eric B.; Foreman-Mackey, Daniel; Fournier, Paul; Fűrész, Gabor; Gaudi, B. Scott; Gregory, Philip C.; Grundahl, Frank; Hatzes, Artie P.; Hébrard, Guillaume; Herrero, Enrique; Hogg, David W.; Howard, Andrew W.; Johnson, John A.; Jorden, Paul; Jurgenson, Colby A.; Latham, David W.; Laughlin, Greg; Loredo, Thomas J.; Lovis, Christophe; Mahadevan, Suvrath; McCracken, Tyler M.; Pepe, Francesco; Perez, Mario; Phillips, David F.; Plavchan, Peter P.; Prato, Lisa; Quirrenbach, Andreas; Reiners, Ansgar; Robertson, Paul; Santos, Nuno C.; Sawyer, David; Segransan, Damien; Sozzetti, Alessandro; Steinmetz, Tilo; Szentgyorgyi, Andrew; Udry, Stéphane; Valenti, Jeff A.; Wang, Sharon X.; Wittenmyer, Robert A.; Wright, Jason T.

    2016-06-01

    The Second Workshop on Extreme Precision Radial Velocities defined circa 2015 the state of the art Doppler precision and identified the critical path challenges for reaching 10 cm s‑1 measurement precision. The presentations and discussion of key issues for instrumentation and data analysis and the workshop recommendations for achieving this bold precision are summarized here. Beginning with the High Accuracy Radial Velocity Planet Searcher spectrograph, technological advances for precision radial velocity (RV) measurements have focused on building extremely stable instruments. To reach still higher precision, future spectrometers will need to improve upon the state of the art, producing even higher fidelity spectra. This should be possible with improved environmental control, greater stability in the illumination of the spectrometer optics, better detectors, more precise wavelength calibration, and broader bandwidth spectra. Key data analysis challenges for the precision RV community include distinguishing center of mass (COM) Keplerian motion from photospheric velocities (time correlated noise) and the proper treatment of telluric contamination. Success here is coupled to the instrument design, but also requires the implementation of robust statistical and modeling techniques. COM velocities produce Doppler shifts that affect every line identically, while photospheric velocities produce line profile asymmetries with wavelength and temporal dependencies that are different from Keplerian signals. Exoplanets are an important subfield of astronomy and there has been an impressive rate of discovery over the past two decades. However, higher precision RV measurements are required to serve as a discovery technique for potentially habitable worlds, to confirm and characterize detections from transit missions, and to provide mass measurements for other space-based missions. The future of exoplanet science has very different trajectories depending on the precision that

  11. Adaptive and Effortful Control and Academic Self-efficacy Beliefs on Achievement: A Longitudinal Study of 1st through 3rd Graders

    PubMed Central

    Liew, Jeffrey; McTigue, Erin; Barrois, Lisa; Hughes, Jan

    2009-01-01

    The linkages between self-regulatory processes and achievement were examined across three years in 733 children beginning at 1st grade (M = 6.57 years, SD = .39 at 1st grade) who were identified as lower achieving in literacy. Accounting for consistencies in measures (from one year prior) and for influences of child’s age, gender, IQ, ethnicity and economic adversity on achievement, results indicate that adaptive/effortful control at 1st grade contributed to both academic self-efficacy beliefs at 2nd grade, and reading (but not math) achievement at 3rd grade. Although academic self-efficacy did not partially mediate the linkage between adaptive/effortful control and achievement, academic self-efficacy beliefs were positively correlated with reading and math. Results support the notion that early efforts to promote children’s self-regulatory skills would enhance future academic self-beliefs and achievement, particularly in literacy. PMID:19169387

  12. Precision Continuum Receivers for Astrophysical Applications

    NASA Technical Reports Server (NTRS)

    Wollack, Edward J.

    2011-01-01

    Cryogenically cooled HEMT (High Electron Mobility Transistor) amplifiers find widespread use in radioastronomy receivers. In recent years, these devices have also been commonly employed in broadband receivers for precision measurements of the Cosmic Microwave Background (CMB) radiation. In this setting, the combination of ultra-low-noise and low-spectral-resolution observations reinforce the importance achieving suitable control over the device environment to achieve fundamentally limited receiver performance. The influence of the intrinsic amplifier stability at low frequencies on data quality (e.g., achievable noise and residual temporal correlations), observational and calibration strategies, as well as architectural mitigation approaches in this setting will be discussed. The implications of device level 1/f fluctuations reported in the literature on system performance will be reviewed.

  13. Cognition, academic achievement, and epilepsy in school-age children: a case-control study in a developing country.

    PubMed

    Melbourne Chambers, R; Morrison-Levy, N; Chang, S; Tapper, J; Walker, S; Tulloch-Reid, M

    2014-04-01

    We conducted a case-control study of 33 Jamaican children 7 to 12years old with uncomplicated epilepsy and 33 of their classroom peers matched for age and gender to determine whether epilepsy resulted in differences in cognitive ability and school achievement and if socioeconomic status or the environment had a moderating effect on any differences. Intelligence, language, memory, attention, executive function, and mathematics ability were assessed using selected tests from NEPSY, WISCR, TeaCh, WRAT3 - expanded, and Raven's Coloured Progressive Matrices. The child's environment at home was measured using the Middle Childhood HOME inventory. Socioeconomic status was determined from a combination of household, crowding, possessions, and sanitation. We compared the characteristics of the cases and controls and used random effects regression models (using the matched pair as the cluster) to examine the relationship between cognition and epilepsy. We found that there was no significant difference in IQ, but children with epilepsy had lower scores on tests of memory (p<0.05), language (p<0.05), and attention (p<0.01) compared with their controls. In random effects models, epilepsy status had a significant effect on memory (coefficient=-0.14, CI: -0.23, -0.05), language (coefficient=-0.13, CI: -0.23, -0.04), and mathematics ability (coefficient=-0.01, CI: -0.02, -0.00). Adjustment for the home environment and socioeconomic status and inclusion of interaction terms for these variables did not alter these effects. In conclusion, we found that epilepsy status in Jamaican children has a significant effect on performance on tests of memory, language, and mathematics and that this effect is not modified or explained by socioeconomic status or the child's home environment. PMID:24632351

  14. Blood pressure telemonitoring is useful to achieve blood pressure control in inadequately treated patients with arterial hypertension.

    PubMed

    Neumann, C L; Menne, J; Rieken, E M; Fischer, N; Weber, M H; Haller, H; Schulz, E G

    2011-12-01

    Failing to reach blood pressure (BP) goals is one of the main problems in hypertension management. Especially in high-risk patients, intensive monitoring including frequently office visits or new techniques to monitor home BP is required. A total of 60 patients with uncontrolled hypertension were included and randomized into a group with telemetric BP monitoring (TBPM) (n=30) and a control group receiving standard care (n=30). During the 3-month study period, patients received in addition to their antihypertensive pre-treatment up to 2 × 300 mg irbesartan to achieve the required target BP. All patients were instructed to measure their BP once daily in the morning. In the TBPM group automatic alerts were generated by the central database server using pre-defined algorithms and patients were subsequently contacted by the physician. At baseline mean 24-h ambulant BP monitoring (ABPM) was 143.3±11.1/82.6±9.9 mm Hg in the TBPM group and 141.4±12.6/82.1±6.5 mm Hg in the standard care group. During treatment mean systolic BP showed a more intensive decrease in the TBPM vs control group (-17.0±11.1 mm Hg vs -9.8±13.7 mm Hg; P=0.032). Patients in the TBPM group had a more pronounced night dipping and a higher reduction of mean pulse pressure than controls (-8.1±5.9 mm Hg vs -2.8±7.4 mm Hg, P=0.004). After 3 months, TBPM-treated patients were given a higher mean daily dose of irbesartan (375±187 mg vs 222±147 mg in controls; P=<0.001). We demonstrated that with TBPM a more effective and faster titration of the antihypertensive agent is possible. The alarm criteria chosen were useful to improve BP control. PMID:21228822

  15. Motion control of the wedge prisms in Risley-prism-based beam steering system for precise target tracking.

    PubMed

    Zhou, Yuan; Lu, Yafei; Hei, Mo; Liu, Guangcan; Fan, Dapeng

    2013-04-20

    Two exact inverse solutions of Risley prisms have been given by previous authors, based on which we calculate the gradients of the scan field that open a way to investigate the nonlinear relationship between the slewing rate of the beam and the required angular velocities of the two wedge prisms in the Risley-prism-based beam steering system for target tracking. The limited regions and singularity point at the center and the edge of the field of regard are discussed. It is found that the maximum required rotational velocities of the two prisms for target tracking are nearly the same and are dependent on the altitude angle. The central limited region is almost independent of the prism parameters. The control singularity at the crossing center path can be avoided by switching the two solutions. PMID:23669697

  16. Helium thrustor propulsion system for precise attitude control and drag compensation of the gravity Probe-B satellite

    NASA Astrophysics Data System (ADS)

    Chen, J. H.

    1984-09-01

    This thesis is concerned with: (1) the design and test of proportional helium thrustors, and (2) the optimal configuration of the thrustors for attitude control and drag compensation of the gravity probe-B spacecraft. The propellant for the helium thrustors is the constant boiloff waste gas from cryogenic liquid helium. Differential thrust is obtained by movement of a spool located between two opposing nozzles thus differentially restricting the helium flow. The design procedure and test results of a high bandwidth, low power, good linear electromagnetic actuator for the spool movement are presented. Test of the thrustor in a vacuum chamber to evaluate its performance has also been done. Two mathematical models are used to describe the helium flow through the thrustor under difficult flow conditions. The experimental data measured in the vacuum chamber and the computational results from the mathematical models are compared.

  17. Precise, motion-free polarization control in Second Harmonic Generation microscopy using a liquid crystal modulator in the infinity space.

    PubMed

    Lien, Chi-Hsiang; Tilbury, Karissa; Chen, Shean-Jen; Campagnola, Paul J

    2013-01-01

    Second Harmonic Generation (SHG) microscopy coupled with polarization analysis has great potential for use in tissue characterization, as molecular and supramolecular structural details can be extracted. Such measurements are difficult to perform quickly and accurately. Here we present a new method that uses a liquid crystal modulator (LCM) located in the infinity space of a SHG laser scanning microscope that allows the generation of any desired linear or circular polarization state. As the device contains no moving parts, polarization can be rotated accurately and faster than by manual or motorized control. The performance in terms of polarization purity was validated using Stokes vector polarimetry, and found to have minimal residual polarization ellipticity. SHG polarization imaging characteristics were validated against well-characterized specimens having cylindrical and/or linear symmetries. The LCM has a small footprint and can be implemented easily in any standard microscope and is cost effective relative to other technologies. PMID:24156059

  18. A widely tunable fiber ring laser with closed loop control based on high-precision stepper motor

    NASA Astrophysics Data System (ADS)

    Wang, Li-li; Xin, Xiang-jun; Zhu, Lin-wei

    2016-05-01

    A tunable single-longitudinal mode erbium-doped fiber ring laser based on stepper motor and closed loop control is proposed and demonstrated. The system consists of an erbium-doped fiber (EDF), a tunable fiber Bragg grating (FBG) filter and a wavelength detector. The characteristics of output laser, such as output power, power stability and 3-dB linewidth, are investigated in the operation range of 1 531—1 569 nm. The repeated experimental results of the fiber laser show that the 3-dB linewidth is less than 17 ps, the side-mode suppression ratio ( SMSR) is up to 60 dB, the output power is up to 1.37 dBm, and the power variation is less than 0.61 dB.

  19. Interactive Instructional Video-Tapes, Scholastic Aptitude, Cognitive Development and Locus of Control as Variables Influencing Science Achievement.

    ERIC Educational Resources Information Center

    Yeany, Russell H.; And Others

    Results are reported of a study that: (1) examined the relationships between university students' entry characteristics and achievement in biological science; and (2) assessed the effectiveness of interactive instructional video-tapes in improving science achievement. Among the variables examined as likely to predict achievement were scholastic…

  20. Ultra high vacuum high precision low background setup with temperature control for thermal desorption mass spectroscopy (TDA-MS) of hydrogen in metals.

    PubMed

    Merzlikin, Sergiy V; Borodin, S; Vogel, D; Rohwerder, M

    2015-05-01

    In this work, a newly developed UHV-based high precision low background setup for hydrogen thermal desorption analysis (TDA) of metallic samples is presented. Using an infrared heating with a low thermal capacity enables a precise control of the temperature and rapid cool down of the measurement chamber. This novel TDA-set up is superior in sensitivity to almost every standard hydrogen analyzer available commercially due to the special design of the measurement chamber, resulting in a very low hydrogen background. No effects of background drift characteristic as for carrier gas based TDA instruments were observed, ensuring linearity and reproducibility of the analysis. This setup will prove to be valuable for detailed investigations of hydrogen trapping sites in steels and other alloys. With a determined limit of detection of 5.9×10(-3)µg g(-1) hydrogen the developed instrument is able to determine extremely low hydrogen amounts even at very low hydrogen desorption rates. This work clearly demonstrates the great potential of ultra-high vacuum thermal desorption mass spectroscopy instrumentation. PMID:25702992