Experimental Study of Active Vibration Control of Planar 3-RRR Flexible Parallel Robots Mechanism

Directory of Open Access Journals (Sweden)

Qinghua Zhang

2016-01-01

Full Text Available An active vibration control experiment of planar 3-RRR flexible parallel robots is implemented in this paper. Considering the direct and inverse piezoelectric effect of PZT material, a general motion equation is established. A strain rate feedback controller is designed based on the established general motion equation. Four control schemes are designed in this experiment: three passive flexible links are controlled at the same time, only passive flexible link 1 is controlled, only passive flexible link 2 is controlled, and only passive flexible link 3 is controlled. The experimental results show that only one flexible link controlled scheme  suppresses elastic vibration and cannot suppress the elastic vibration of the other flexible links, whereas when three passive flexible links are controlled at the same time, they are able to effectively suppress the elastic vibration of all of the flexible links. In general, the experiment verifies that a strain rate feedback controller is able to effectively suppress the elastic vibration of the flexible links of plane 3-RRR flexible parallel robots.

Robust on-off pulse control of flexible space vehicles

Science.gov (United States)

Wie, Bong; Sinha, Ravi

1993-01-01

The on-off reaction jet control system is often used for attitude and orbital maneuvering of various spacecraft. Future space vehicles such as the orbital transfer vehicles, orbital maneuvering vehicles, and space station will extensively use reaction jets for orbital maneuvering and attitude stabilization. The proposed robust fuel- and time-optimal control algorithm is used for a three-mass spacing model of flexible spacecraft. A fuel-efficient on-off control logic is developed for robust rest-to-rest maneuver of a flexible vehicle with minimum excitation of structural modes. The first part of this report is concerned with the problem of selecting a proper pair of jets for practical trade-offs among the maneuvering time, fuel consumption, structural mode excitation, and performance robustness. A time-optimal control problem subject to parameter robustness constraints is formulated and solved. The second part of this report deals with obtaining parameter insensitive fuel- and time- optimal control inputs by solving a constrained optimization problem subject to robustness constraints. It is shown that sensitivity to modeling errors can be significantly reduced by the proposed, robustified open-loop control approach. The final part of this report deals with sliding mode control design for uncertain flexible structures. The benchmark problem of a flexible structure is used as an example for the feedback sliding mode controller design with bounded control inputs and robustness to parameter variations is investigated.

Synergy of multi-scale toughening and protective mechanisms at hierarchical branch-stem interfaces

Science.gov (United States)

Müller, Ulrich; Gindl-Altmutter, Wolfgang; Konnerth, Johannes; Maier, Günther A.; Keckes, Jozef

2015-09-01

Biological materials possess a variety of artful interfaces whose size and properties are adapted to their hierarchical levels and functional requirements. Bone, nacre, and wood exhibit an impressive fracture resistance based mainly on small crystallite size, interface organic adhesives and hierarchical microstructure. Currently, little is known about mechanical concepts in macroscopic biological interfaces like the branch-stem junction with estimated 1014 instances on earth and sizes up to few meters. Here we demonstrate that the crack growth in the upper region of the branch-stem interface of conifer trees proceeds along a narrow predefined region of transversally loaded tracheids, denoted as sacrificial tissue, which fail upon critical bending moments on the branch. The specific arrangement of the tracheids allows disconnecting the overloaded branch from the stem in a controlled way by maintaining the stem integrity. The interface microstructure based on the sharply adjusted cell orientation and cell helical angle secures a zig-zag crack propagation path, mechanical interlock closing after the bending moment is removed, crack gap bridging and self-repairing by resin deposition. The multi-scale synergetic concepts allows for a controllable crack growth between stiff stem and flexible branch, as well as mechanical tree integrity, intact physiological functions and recovery after the cracking.

Dealing with Flexible Modes in 6 DOFs Robust Servo Control

NARCIS (Netherlands)

Oomen, T.A.E.; Bosgra, O.H.; Angelis, G.Z.

2007-01-01

Control of high performance multi-input multi-output electromechanical systems with flexible dynamics is investigated. Present feedforward and feedback control design approaches mainly focus on rigid-body plant behaviour. To achieve higher performance, flexible dynamics should be explicitly

New flexible thermal control material for long-life satellite

International Nuclear Information System (INIS)

Sasaki, Shigekuni; Hasuda, Yoshinori; Ichino, Toshihiro

1986-01-01

Flexible thermal control materials are light weight, cheap and excellent in the practical applicability, and are expected to be applied to future long life, large capacity satellites. However, the flexible thermal control materials used at present have the defect that either the space environment withstanding capability or the thermal control performance is poor. Therefore, the authors examined the flexible thermal control materials which are excellent in both these properties, and have developed the thermal control material PEI-OSR using polyether imide films as the substrate. In this study, while comparing with the FEP Teflon with silver vapor deposition, which has been used so far for short life satellites, the long term reliability of the PEI-OSR supposing the use for seven years was examined. As the results, the FEP Teflon with silver vapor deposition caused cracking and separation by irradiation and heat cycle test, and became unusable, but the PEI-OSR did not change its flexibility at all. Also the thermal control performance of the PEI-OSR after the test equivalent to seven years was superior to the initial performance of the Kaptone with aluminum vapor deposition, which has excellent space environment endurance, thus it was clarified that the PEI-OSR is the most excellent for this purpose. (Kako, I.)

RESEARCH AREA -- ARTIFICIAL INTELLIGENCE CONTROL (AIR POLLUTION TECHNOLOGY BRANCH, AIR POLLUTION PREVENTION AND CONTROL DIVISION, NRMRL)

Science.gov (United States)

The Air Pollution Technology Branch (APTB) of NRMRL's Air Pollution Prevention and Control Division in Research Triangle Park, NC, has conducted several research projects for evaluating the use of artificial intelligence (AI) to improve the control of pollution control systems an...

Experiments study on attitude coupling control method for flexible spacecraft

Science.gov (United States)

Wang, Jie; Li, Dongxu

2018-06-01

High pointing accuracy and stabilization are significant for spacecrafts to carry out Earth observing, laser communication and space exploration missions. However, when a spacecraft undergoes large angle maneuver, the excited elastic oscillation of flexible appendages, for instance, solar wing and onboard antenna, would downgrade the performance of the spacecraft platform. This paper proposes a coupling control method, which synthesizes the adaptive sliding mode controller and the positive position feedback (PPF) controller, to control the attitude and suppress the elastic vibration simultaneously. Because of its prominent performance for attitude tracking and stabilization, the proposed method is capable of slewing the flexible spacecraft with a large angle. Also, the method is robust to parametric uncertainties of the spacecraft model. Numerical simulations are carried out with a hub-plate system which undergoes a single-axis attitude maneuver. An attitude control testbed for the flexible spacecraft is established and experiments are conducted to validate the coupling control method. Both numerical and experimental results demonstrate that the method discussed above can effectively decrease the stabilization time and improve the attitude accuracy of the flexible spacecraft.

High Accuracy Attitude Control System Design for Satellite with Flexible Appendages

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Wenya Zhou

2014-01-01

Full Text Available In order to realize the high accuracy attitude control of satellite with flexible appendages, attitude control system consisting of the controller and structural filter was designed. When the low order vibration frequency of flexible appendages is approximating the bandwidth of attitude control system, the vibration signal will enter the control system through measurement device to bring impact on the accuracy or even the stability. In order to reduce the impact of vibration of appendages on the attitude control system, the structural filter is designed in terms of rejecting the vibration of flexible appendages. Considering the potential problem of in-orbit frequency variation of the flexible appendages, the design method for the adaptive notch filter is proposed based on the in-orbit identification technology. Finally, the simulation results are given to demonstrate the feasibility and effectiveness of the proposed design techniques.

Foreign Banks: Internal Control and Audit Weaknesses in U.S. Branches

National Research Council Canada - National Science Library

1997-01-01

.... Weaknesses in the branch's internal controls, including inadequate segregation of duties in trading and electronic funds transfer activities, had enabled an employee to trade illegally and to hide...

Modeling and control of flexible space structures

Science.gov (United States)

Wie, B.; Bryson, A. E., Jr.

1981-01-01

The effects of actuator and sensor locations on transfer function zeros are investigated, using uniform bars and beams as generic models of flexible space structures. It is shown how finite element codes may be used directly to calculate transfer function zeros. The impulse response predicted by finite-dimensional models is compared with the exact impulse response predicted by the infinite dimensional models. It is shown that some flexible structures behave as if there were a direct transmission between actuator and sensor (equal numbers of zeros and poles in the transfer function). Finally, natural damping models for a vibrating beam are investigated since natural damping has a strong influence on the appropriate active control logic for a flexible structure.

Module for the organization of a branch of the universal branch driver in the CAMAC standard

International Nuclear Information System (INIS)

Nguen Fuk; Smirnov, V.A.; Khmelevski, E.

1976-01-01

A module is elaborated for the organization of a branch of the universal branch driver in the CAMAC standard for the conjugation of a control crate trunk with a branch trunk. A block diagram of the module is described; its principal specifications are given. The universal branch driver system may accomodate up to 10 branch organization modules with one control source module

Kidney branching morphogenesis under the control of a ligand–receptor-based Turing mechanism

International Nuclear Information System (INIS)

Menshykau, Denis; Iber, Dagmar

2013-01-01

The main signalling proteins that control early kidney branching have been defined. Yet the underlying mechanism is still elusive. We have previously shown that a Schnakenberg-type Turing mechanism can recapitulate the branching and protein expression patterns in wild-type and mutant lungs, but it is unclear whether this mechanism would extend to other branched organs that are regulated by other proteins. Here, we show that the glial cell line-derived neurotrophic factor–RET regulatory interaction gives rise to a Schnakenberg-type Turing model that reproduces the observed budding of the ureteric bud from the Wolffian duct, its invasion into the mesenchyme and the observed branching pattern. The model also recapitulates all relevant protein expression patterns in wild-type and mutant mice. The lung and kidney models are both based on a particular receptor–ligand interaction and require (1) cooperative binding of ligand and receptor, (2) a lower diffusion coefficient for the receptor than for the ligand and (3) an increase in the receptor concentration in response to receptor–ligand binding (by enhanced transcription, more recycling or similar). These conditions are met also by other receptor–ligand systems. We propose that ligand–receptor-based Turing patterns represent a general mechanism to control branching morphogenesis and other developmental processes. (paper)

Real time control of the flexible dynamics of orbital launch vehicles

NARCIS (Netherlands)

Bos, van den J.; Steinbuch, M.; Gutierrez, H.M.

2011-01-01

During this traineeship the flexible dynamics of orbital launch vehicles are estimated and controlled in real time, using distributed fiber-Bragg sensor arrays for motion estimation and cold gas thrusters for control. The use of these cold-gas thrusters to actively control flexible modes is the main

Branched-Chain Aminotransferases Control TORC1 Signaling in Saccharomyces cerevisiae.

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Joanne M Kingsbury

2015-12-01

Full Text Available The conserved target of rapamycin complex 1 (TORC1 integrates nutrient signals to orchestrate cell growth and proliferation. Leucine availability is conveyed to control TORC1 activity via the leu-tRNA synthetase/EGOC-GTPase module in yeast and mammals, but the mechanisms sensing leucine remain only partially understood. We show here that both leucine and its α-ketoacid metabolite, α-ketoisocaproate, effectively activate the yeast TORC1 kinase via both EGOC GTPase-dependent and -independent mechanisms. Leucine and α-ketoisocaproate are interconverted by ubiquitous branched-chain aminotransferases (BCAT, which in yeast are represented by the mitochondrial and cytosolic enzymes Bat1 and Bat2, respectively. BCAT yeast mutants exhibit severely compromised TORC1 activity, which is partially restored by expression of Bat1 active site mutants, implicating both catalytic and structural roles of BCATs in TORC1 control. We find that Bat1 interacts with branched-chain amino acid metabolic enzymes and, in a leucine-dependent fashion, with the tricarboxylic acid (TCA-cycle enzyme aconitase. BCAT mutation perturbed TCA-cycle intermediate levels, consistent with a TCA-cycle block, and resulted in low ATP levels, activation of AMPK, and TORC1 inhibition. We propose the biosynthetic capacity of BCAT and its role in forming multicomplex metabolons connecting branched-chain amino acids and TCA-cycle metabolism governs TCA-cycle flux to activate TORC1 signaling. Because mammalian mitochondrial BCAT is known to form a supramolecular branched-chain α-keto acid dehydrogenase enzyme complex that links leucine metabolism to the TCA-cycle, these findings establish a precedent for understanding TORC1 signaling in mammals.

Robotic Control of a Traditional Flexible Endoscope for Therapy

NARCIS (Netherlands)

Ruiter, Jeroen; Bonnema, Gerrit Maarten; van der Voort, Mascha C.; Broeders, Ivo Adriaan Maria Johannes

2013-01-01

In therapeutic flexible endoscopy a team of physician and assistant(s) is required to control all independent translations and rotations of the flexible endoscope and its instruments. As a consequence the physician lacks valuable force feedback information on tissue interaction, communication errors

Environmental control of branching in petunia.

Science.gov (United States)

Drummond, Revel S M; Janssen, Bart J; Luo, Zhiwei; Oplaat, Carla; Ledger, Susan E; Wohlers, Mark W; Snowden, Kimberley C

2015-06-01

Plants alter their development in response to changes in their environment. This responsiveness has proven to be a successful evolutionary trait. Here, we tested the hypothesis that two key environmental factors, light and nutrition, are integrated within the axillary bud to promote or suppress the growth of the bud into a branch. Using petunia (Petunia hybrida) as a model for vegetative branching, we manipulated both light quality (as crowding and the red-to-far-red light ratio) and phosphate availability, such that the axillary bud at node 7 varied from deeply dormant to rapidly growing. In conjunction with the phenotypic characterization, we also monitored the state of the strigolactone (SL) pathway by quantifying SL-related gene transcripts. Mutants in the SL pathway inhibit but do not abolish the branching response to these environmental signals, and neither signal is dominant over the other, suggesting that the regulation of branching in response to the environment is complex. We have isolated three new putatively SL-related TCP (for Teosinte branched1, Cycloidia, and Proliferating cell factor) genes from petunia, and have identified that these TCP-type transcription factors may have roles in the SL signaling pathway both before and after the reception of the SL signal at the bud. We show that the abundance of the receptor transcript is regulated by light quality, such that axillary buds growing in added far-red light have greatly increased receptor transcript abundance. This suggests a mechanism whereby the impact of any SL signal reaching an axillary bud is modulated by the responsiveness of these cells to the signal. © 2015 American Society of Plant Biologists. All Rights Reserved.

Flexible AC transmission systems modelling and control

CERN Document Server

Zhang, Xiao-Ping; Pal, Bikash

2012-01-01

The extended and revised second edition of this successful monograph presents advanced modeling, analysis and control techniques of Flexible AC Transmission Systems (FACTS). The book covers comprehensively a range of power-system control problems: from steady-state voltage and power flow control, to voltage and reactive power control, to voltage stability control, to small signal stability control using FACTS controllers. In the six years since the first edition of the book has been published research on the FACTS has continued to flourish while renewable energy has developed into a mature and

Abscisic acid signaling is controlled by a BRANCHED1/HD-ZIP i cascade in Arabidopsis axillary buds

NARCIS (Netherlands)

Gonzalez-Grandio, Eduardo; Pajoro, Alice; Franco-Zorrilla, Jose M.; Tarancon, Carlos; Immink, Richard G.H.; Cubas, Pilar

2017-01-01

Shoot-branching patterns determine key aspects of plant life and are important targets for crop breeding. However, we are still largely ignorant of the genetic networks controlling locally themost important decision during branch development: whether the axillary bud, or branch primordium, grows out

Flexible spacecraft dynamics, control and guidance technologies by giovanni campolo

CERN Document Server

Mazzini, Leonardo

2016-01-01

This book is an up-to-date compendium on spacecraft attitude and orbit control (AOC) that offers a systematic and complete treatment of the subject with the aim of imparting the theoretical and practical knowledge that is required by designers, engineers, and researchers. After an introduction on the kinematics of the flexible and agile space vehicles, the modern architecture and functions of an AOC system are described and the main AOC modes reviewed with possible design solutions and examples. The dynamics of the flexible body in space are then considered using an original Lagrangian approach suitable for the control applications of large space flexible structures. Subsequent chapters address optimal control theory, attitude control methods, and orbit control applications, including the optimal orbital transfer with finite and infinite thrust. The theory is integrated with a description of current propulsion systems, with the focus especially on the new electric propulsion systems and state of the art senso...

Two-Link Flexible Manipulator Control Using Sliding Mode Control Based Linear Matrix Inequality

Science.gov (United States)

Zulfatman; Marzuki, Mohammad; Alif Mardiyah, Nur

2017-04-01

Two-link flexible manipulator is a manipulator robot which at least one of its arms is made of lightweight material and not rigid. Flexible robot manipulator has some advantages over the rigid robot manipulator, such as lighter, requires less power and costs, and to result greater payload. However, suitable control algorithm to maintain the two-link flexible robot manipulator in accurate positioning is very challenging. In this study, sliding mode control (SMC) was employed as robust control algorithm due to its insensitivity on the system parameter variations and the presence of disturbances when the system states are sliding on a sliding surface. SMC algorithm was combined with linear matrix inequality (LMI), which aims to reduce the effects of chattering coming from the oscillation of the state during sliding on the sliding surface. Stability of the control algorithm is guaranteed by Lyapunov function candidate. Based on simulation works, SMC based LMI resulted in better performance improvements despite the disturbances with significant chattering reduction. This was evident from the decline of the sum of squared tracking error (SSTE) and the sum of squared of control input (SSCI) indexes respectively 25.4% and 19.4%.

Advanced Branching Control and Characterization of Inorganic Semiconducting Nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Hughes, Steven Michael [Univ. of California, Berkeley, CA (United States)

2007-01-01

The ability to finely tune the size and shape of inorganic semiconducting nanocrystals is an area of great interest, as the more control one has, the more applications will be possible for their use. The first two basic shapes develped in nanocrystals were the sphere and the anistropic nanorod. the II_VI materials being used such as Cadmium Selenide (CdSe) and Cadmium Telluride (CdTe), exhibit polytypism, which allows them to form in either the hexagonally packed wurtzite or cubically packed zinc blende crystalline phase. The nanorods are wurtzite with the length of the rod growing along the c-axis. As this grows, stacking faults may form, which are layers of zinc blende in the otherwise wurtzite crystal. Using this polytypism, though, the first generation of branched crystals were developed in the form of the CdTe tetrapod. This is a nanocrystal that nucleates in the zincblend form, creating a tetrahedral core, on which four wurtzite arms are grown. This structure opened up the possibility of even more complex shapes and applications. This disseration investigates the advancement of branching control and further understanding the materials polytypism in the form of the stacking faults in nanorods.

Indirect control of flexible demand for power system applications

DEFF Research Database (Denmark)

Sossan, Fabrizio

This thesis addresses the topic of control of flexible demand to provide support to the operation of the electric power system. We focus on the indirect control approach, a framework that enables demand response by means of a consumption incentive signal. Initially, the concept of flexibility...... a shift in the consumption according to an indirect control signal. We present from simple control algorithms with a few requirements up to model predictive control strategies. The performance of the indirect control algorithms are compared by means of hardware-in-the-loop simulations using Power...... and storage in the operation of the future power system, we develop a model predictive control strategy for a smart building with the objective of supplying iii space heating and providing regulating power to the grid according to a dynamic electricity price. We named this application energy replacement...

A novel branched side-chain-type sulfonated polyimide membrane with flexible sulfoalkyl pendants and trifluoromethyl groups for vanadium redox flow batteries

Science.gov (United States)

Li, Jinchao; Liu, Suqin; He, Zhen; Zhou, Zhi

2017-04-01

A novel branched side-chain-type sulfonated polyimide (6F-s-bSPI) membrane with accessible branching agents of melamine, hydrophobic trifluoromethyl groups (sbnd CF3), and flexible sulfoalkyl pendants is prepared by a high-temperature polycondensation and post-sulfonation method for use in vanadium redox flow batteries (VRFBs). The chemical structure of the 6F-s-bSPI membrane is confirmed by ATR-FTIR and 1H NMR spectra. The physico-chemical properties of the as-prepared 6F-s-bSPI membrane are systematically investigated and found to be strongly related to the specially designed structure. The 6F-s-bSPI membrane offers a reduced cost and possesses a significantly lowered vanadium ion permeability (1.18 × 10-7 cm2 min-1) compared to the linear SPI (2.25 × 10-7 cm2 min-1) and commercial Nafion 115 (1.36 × 10-6 cm2 min-1) membranes, prolonging the self-discharge duration of the VRFBs. In addition, the VRFB assembled with a 6F-s-bSPI membrane shows higher coulombic (98.3%-99.7%) and energy efficiencies (88.4%-66.12%) than that with a SPI or Nafion 115 membrane under current densities ranging from 20 to 100 mA cm-2. Moreover, the VRFB with a 6F-s-bSPI membrane delivers a stable cycling performance over 100 cycles with no decline in coulombic and energy efficiencies. These results show that the branched side-chain-type structure is a promising design to prepare excellent proton conductive membranes.

Self-Tuning Vibration Control of a Rotational Flexible Timoshenko Arm Using Neural Networks

Directory of Open Access Journals (Sweden)

Minoru Sasaki

2012-01-01

Full Text Available A self-tuning vibration control of a rotational flexible arm using neural networks is presented. To the self-tuning control system, the control scheme consists of gain tuning neural networks and a variable-gain feedback controller. The neural networks are trained so as to make the root moment zero. In the process, the neural networks learn the optimal gain of the feedback controller. The feedback controller is designed based on Lyapunov's direct method. The feedback control of the vibration of the flexible system is derived by considering the time rate of change of the total energy of the system. This approach has the advantage over the conventional methods in the respect that it allows one to deal directly with the system's partial differential equations without resorting to approximations. Numerical and experimental results for the vibration control of a rotational flexible arm are discussed. It verifies that the proposed control system is effective at controlling flexible dynamical systems.

H infinity controller design to a rigid-flexible satellite with two vibration modes

International Nuclear Information System (INIS)

De Souza, A G; De Souza, L C G

2015-01-01

The satellite attitude control system (ACS) design becomes more complex when the satellite structure has components like, flexible solar panels, antennas and mechanical manipulators. These flexible structures can interact with the satellite rigid parts during translational and/or rotational manoeuvre damaging the ACS pointing accuracy. Although, a well-designed controller can suppress such disturbances quickly, the controller error pointing may be limited by the minimum time necessary to suppress such disturbances thus affecting the satellite attitude acquisition. This paper deals with the rigid-flexible satellite ACS design using the H infinity method. The rigid-flexible satellite is represented by a beam connected to a central rigid hub at one end and free at the other one. The equations of motions are obtained considering small flexible deformations and the Euler-Bernoulli hypothesis. The results of the simulations have shown that the H-infinity controller was able to control the rigid motion and suppress the vibrations. (paper)

Vibration control of a flexible structure with electromagnetic actuators

DEFF Research Database (Denmark)

Gruzman, Maurício; Santos, Ilmar

2016-01-01

This work presents the model of a shear-frame-type structure composed of six flexible beams and three rigid masses. Fixed on the ground, outside the structure, two voltage-controlled electromagnetic actuators are used for vibration control. To model the flexible beams, unidimensional finite...... elements were used. Nonlinear equations for the actuator electromagnetic force, noise in the position sensor, time delays for the control signal update and voltage saturation were also considered in the model. For controlling purposes, a discrete linear quadratic regulator combined with a predictive full......-order discrete linear observer was employed. Results of numerical simulations, where the structure is submitted to an impulsive disturbance force and to a harmonic force, show that the oscillations can be significantly reduced with the use of the electromagnetic actuators....

Flexibility of trunnion piping elbows

International Nuclear Information System (INIS)

Lewis, G.D.; Chao, Y.J.

1987-01-01

Flexibility factors and stress indices for piping component such as straight pipe, elbows, butt-welding tees, branch connections, and butt-welding reducers are contained in the code, but many of the less common piping components, like the trunnion elbow, do not have flexibility factors or stress indices defined. The purpose of this paper is to identify the in-plane and out-of-plane flexibility factors in accordance with code procedures for welded trunnions attached to the tangent centerlines of long radius elbows. This work utilized the finite element method as applicable to plates and shells for calculating the relative rotations of the trunnion elbow-ends for in-plane and out-of-plane elbow moment loadings. These rotations are used to derive the corresponding in-plane and out-of-plane flexibility factors. (orig./GL)

Flexibility and Control : An empirical study relating production flexibility to the design of performance management systems

NARCIS (Netherlands)

Van Veen-Dirks, P.M.G.

2002-01-01

A critical challenge facing organizations is the design of management control systems, which play a key role in evaluating the achievement of organizational and individual objectives. This thesis addresses the design of management control (performance management) systems in the current flexible

Controlled synthesis of ZnO branched nanorod arrays by hierarchical solution growth and application in dye-sensitized solar cells

International Nuclear Information System (INIS)

Fang Xiaoming; Peng Lihua; Shang Xiaoying; Zhang Zhengguo

2011-01-01

We demonstrate the controlled synthesis of ZnO branched nanorod arrays on fluorine-doped SnO 2 -coated glass substrates by the hierarchical solution growth method. In the secondary growth, the concentration of Zn(NO 3 ) 2 /hexamethylenetetramine plays an important role in controlling the morphology of the branched nanorod arrays, besides that of diaminopropane used as a structure-directing agent to induce the growth of branches. The population density and morphology of the branched nanorod arrays depend on those of the nanorod arrays obtained from the primary growth, which can be modulated though the concentration of Zn(NO 3 ) 2 /hexamethylenetetramine in the primary growth solution. The dye-sensitized ZnO branched nanorod arrays exhibit much stronger optical absorption as compared with its corresponding primary nanorod arrays, suggesting that the addition of the branches improves light harvesting. The dye-sensitized solar cell based on the optimized ZnO branched nanorod array reaches a conversion efficiency of 1.66% under the light radiation of 1000 W/m 2 . The branched nanorod arrays can also be applied in other application fields of ZnO.

Experimental Study of Flexible Plate Vibration Control by Using Two-Loop Sliding Mode Control Strategy

Science.gov (United States)

Yang, Jingyu; Lin, Jiahui; Liu, Yuejun; Yang, Kang; Zhou, Lanwei; Chen, Guoping

2017-08-01

It is well known that intelligent control theory has been used in many research fields, novel modeling method (DROMM) is used for flexible rectangular active vibration control, and then the validity of new model is confirmed by comparing finite element model with new model. In this paper, taking advantage of the dynamics of flexible rectangular plate, a two-loop sliding mode (TSM) MIMO approach is introduced for designing multiple-input multiple-output continuous vibration control system, which can overcome uncertainties, disturbances or unstable dynamics. An illustrative example is given in order to show the feasibility of the method. Numerical simulations and experiment confirm the effectiveness of the proposed TSM MIMO controller.

Distributed flow sensing for closed-loop speed control of a flexible fish robot.

Science.gov (United States)

Zhang, Feitian; Lagor, Francis D; Yeo, Derrick; Washington, Patrick; Paley, Derek A

2015-10-23

Flexibility plays an important role in fish behavior by enabling high maneuverability for predator avoidance and swimming in turbulent flow. This paper presents a novel flexible fish robot equipped with distributed pressure sensors for flow sensing. The body of the robot is molded from soft, hyperelastic material, which provides flexibility. Its Joukowski-foil shape is conducive to modeling the fluid analytically. A quasi-steady potential-flow model is adopted for real-time flow estimation, whereas a discrete-time vortex-shedding flow model is used for higher-fidelity simulation. The dynamics for the flexible fish robot yield a reduced model for one-dimensional swimming. A recursive Bayesian filter assimilates pressure measurements to estimate flow speed, angle of attack, and foil camber. The closed-loop speed-control strategy combines an inverse-mapping feedforward controller based on an average model derived for periodic actuation of angle-of-attack and a proportional-integral feedback controller utilizing the estimated flow information. Simulation and experimental results are presented to show the effectiveness of the estimation and control strategy. The paper provides a systematic approach to distributed flow sensing for closed-loop speed control of a flexible fish robot by regulating the flapping amplitude.

Improving Delay-Margin of Noncollocated Vibration Control of Piezo-Actuated Flexible Beams via a Fractional-Order Controller

Directory of Open Access Journals (Sweden)

Teerawat Sangpet

2014-01-01

Full Text Available Noncollocated control of flexible structures results in nonminimum-phase systems because the separation between the actuator and the sensor creates an input-output delay. The delay can deteriorate stability of closed-loop systems. This paper presents a simple approach to improve the delay-margin of the noncollocated vibration control of piezo-actuated flexible beams using a fractional-order controller. Results of real life experiments illustrate efficiency of the controller and show that the fractional-order controller has better stability robustness than the integer-order controller.

An Intelligent Control for the Distributed Flexible Network Photovoltaic System using Autonomous Control and Agent

Science.gov (United States)

Park, Sangsoo; Miura, Yushi; Ise, Toshifumi

This paper proposes an intelligent control for the distributed flexible network photovoltaic system using autonomous control and agent. The distributed flexible network photovoltaic system is composed of a secondary battery bank and a number of subsystems which have a solar array, a dc/dc converter and a load. The control mode of dc/dc converter can be selected based on local information by autonomous control. However, if only autonomous control using local information is applied, there are some problems associated with several cases such as voltage drop on long power lines. To overcome these problems, the authors propose introducing agents to improve control characteristics. The autonomous control with agents is called as intelligent control in this paper. The intelligent control scheme that employs the communication between agents is applied for the model system and proved with simulation using PSCAD/EMTDC.

Control of a flexible bracing manipulator: Integration of current research work to realize the bracing manipulator

Science.gov (United States)

Kwon, Dong-Soo

1991-01-01

All research results about flexible manipulator control were integrated to show a control scenario of a bracing manipulator. First, dynamic analysis of a flexible manipulator was done for modeling. Second, from the dynamic model, the inverse dynamic equation was derived, and the time domain inverse dynamic method was proposed for the calculation of the feedforward torque and the desired flexible coordinate trajectories. Third, a tracking controller was designed by combining the inverse dynamic feedforward control with the joint feedback control. The control scheme was applied to the tip position control of a single link flexible manipulator for zero and non-zero initial condition cases. Finally, the contact control scheme was added to the position tracking control. A control scenario of a bracing manipulator is provided and evaluated through simulation and experiment on a single link flexible manipulator.

The Proprotein Convertase KPC-1/Furin Controls Branching and Self-avoidance of Sensory Dendrites in Caenorhabditis elegans

Science.gov (United States)

Bülow, Hannes E.

2014-01-01

Animals sample their environment through sensory neurons with often elaborately branched endings named dendritic arbors. In a genetic screen for genes involved in the development of the highly arborized somatosensory PVD neuron in C. elegans, we have identified mutations in kpc-1, which encodes the homolog of the proprotein convertase furin. We show that kpc-1/furin is necessary to promote the formation of higher order dendritic branches in PVD and to ensure self-avoidance of sister branches, but is likely not required during maintenance of dendritic arbors. A reporter for kpc-1/furin is expressed in neurons (including PVD) and kpc-1/furin can function cell-autonomously in PVD neurons to control patterning of dendritic arbors. Moreover, we show that kpc-1/furin also regulates the development of other neurons in all major neuronal classes in C. elegans, including aspects of branching and extension of neurites as well as cell positioning. Our data suggest that these developmental functions require proteolytic activity of KPC-1/furin. Recently, the skin-derived MNR-1/menorin and the neural cell adhesion molecule SAX-7/L1CAM have been shown to act as a tripartite complex with the leucine rich transmembrane receptor DMA-1 on PVD mechanosensory to orchestrate the patterning of dendritic branches. Genetic analyses show that kpc-1/furin functions in a pathway with MNR-1/menorin, SAX-7/L1CAM and DMA-1 to control dendritic branch formation and extension of PVD neurons. We propose that KPC-1/furin acts in concert with the ‘menorin’ pathway to control branching and growth of somatosensory dendrites in PVD. PMID:25232734

Design, Prototyping and Control of a Flexible Cystoscope for Biomedical Applications

Science.gov (United States)

Sozer, Canberk; Ghorbani, Morteza; Alcan, Gokhan; Uvet, Huseyin; Unel, Mustafa; Kosar, Ali

2017-07-01

Kidney stone and prostate hyperplasia are very common urogenital diseases all over the world. To treat these diseases, one of the ESWL (Extracorporeal Shock Wave Lithotripsy), PCNL (Percutaneous Nephrolithotomy), cystoscopes or open surgery techniques can be used. Cystoscopes named devices are used for in-vivo intervention. A flexible or rigid cystoscope device is inserted into human body and operates on interested area. In this study, a flexible cystoscope prototype has been developed. The prototype is able to bend up to ±40°in X and Y axes, has a hydrodynamic cavitation probe for rounding sharp edges of kidney stone or resection of the filled prostate with hydrodynamic cavitation method and contains a waterproof medical camera to give visual feedback to the operator. The operator steers the flexible end-effector via joystick toward target region. This paper presents design, manufacturing, control and experimental setup of the tendon driven flexible cystoscope prototype. The prototype is 10 mm in outer diameter, 70 mm in flexible part only and 120 mm in total length with flexible part and rigid tube. The experimental results show that the prototype bending mechanism, control system, manufactured prototype parts and experimental setup function properly. A small piece of real kidney stone was broken in targeted area.

Controlling flow time delays in flexible manufacturing cells

NARCIS (Netherlands)

Slomp, J.; Caprihan, R.; Bokhorst, J. A. C.

2009-01-01

Flow time delays in Flexible Manufacturing Cells (FMCs) are caused by transport and clamping/reclamping activities. This paper shows how dynamic scheduling parameters may control the flow times of jobs and the available task windows for flow time delays.

Invasive Species Science Branch: research and management tools for controlling invasive species

Science.gov (United States)

Reed, Robert N.; Walters, Katie D.

2015-01-01

Invasive, nonnative species of plants, animals, and disease organisms adversely affect the ecosystems they enter. Like “biological wildfires,” they can quickly spread and affect nearly all terrestrial and aquatic ecosystems. Invasive species have become one of the greatest environmental challenges of the 21st century in economic, environmental, and human health costs, with an estimated effect in the United States of more than $120 billion per year. Managers of the Department of the Interior and other public and private lands often rank invasive species as their top resource management problem. The Invasive Species Science Branch of the Fort Collins Science Center provides research and technical assistance relating to management concerns for invasive species, including understanding how these species are introduced, identifying areas vulnerable to invasion, forecasting invasions, and developing control methods. To disseminate this information, branch scientists are developing platforms to share invasive species information with DOI cooperators, other agency partners, and the public. From these and other data, branch scientists are constructing models to understand and predict invasive species distributions for more effective management. The branch also has extensive herpetological and population biology expertise that is applied to harmful reptile invaders such as the Brown Treesnake on Guam and Burmese Python in Florida.

Nonlinear vibration with control for flexible and adaptive structures

CERN Document Server

Wagg, David

2015-01-01

This book provides a comprehensive discussion of nonlinear multi-modal structural vibration problems, and shows how vibration suppression can be applied to such systems by considering a sample set of relevant control techniques. It covers the basic principles of nonlinear vibrations that occur in flexible and/or adaptive structures, with an emphasis on engineering analysis and relevant control techniques. Understanding nonlinear vibrations is becoming increasingly important in a range of engineering applications, particularly in the design of flexible structures such as aircraft, satellites, bridges, and sports stadia. There is an increasing trend towards lighter structures, with increased slenderness, often made of new composite materials and requiring some form of deployment and/or active vibration control. There are also applications in the areas of robotics, mechatronics, micro electrical mechanical systems, non-destructive testing and related disciplines such as structural health monitoring. Two broader ...

Power control flexibilities for grid-connected multi-functional photovoltaic inverters

DEFF Research Database (Denmark)

Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

2014-01-01

to reduced cost of energy. To implement the advanced features, a flexible power controller is developed in this paper, which can be configured in the PV inverter and flexibly be changed from one to another. This power control strategy is based on the single-phase PQ theory, and it offers the possibilities...... of ancillary and intelligent services, like Low Voltage Ride-Through (LVRT), reactive power compensation, and reliability-oriented thermal management/control by PV systems is a key to attain higher utilization of solar energy. Those essential functionalities for the future PV inverters can contribute...... to generate appropriate references for the inner current control loop. The references depend on the system conditions and also specific demands from both system operators and customers. Besides, this power control strategy can be implemented in a commercial PV inverter as standardized functions, and also...

Current perspectives on shoot branching regulation

Directory of Open Access Journals (Sweden)

Cunquan YUAN,Lin XI,Yaping KOU,Yu ZHAO,Liangjun ZHAO

2015-03-01

Full Text Available Shoot branching is regulated by the complex interactions among hormones, development, and environmental factors. Recent studies into the regulatory mecha-nisms of shoot branching have focused on strigolactones, which is a new area of investigation in shoot branching regulation. Elucidation of the function of the D53 gene has allowed exploration of detailed mechanisms of action of strigolactones in regulating shoot branching. In addition, the recent discovery that sucrose is key for axillary bud release has challenged the established auxin theory, in which auxin is the principal agent in the control of apical dominance. These developments increase our understan-ding of branching control and indicate that regulation of shoot branching involves a complex network. Here, we first summarize advances in the systematic regulatory network of plant shoot branching based on current information. Then we describe recent developments in the synthesis and signal transduction of strigolactones. Based on these considerations, we further summarize the plant shoot branching regulatory network, including long distance systemic signals and local gene activity mediated by strigolactones following perception of external envi-ronmental signals, such as shading, in order to provide a comprehensive overview of plant shoot branching.

Design and Nonlinear Control of a 2-DOF Flexible Parallel Humanoid Arm Joint Robot

Directory of Open Access Journals (Sweden)

Leijie Jiang

2017-01-01

Full Text Available The paper focuses on the design and nonlinear control of the humanoid wrist/shoulder joint based on the cable-driven parallel mechanism which can realize roll and pitch movement. In view of the existence of the flexible parts in the mechanism, it is necessary to solve the vibration control of the flexible wrist/shoulder joint. In this paper, a cable-driven parallel robot platform is developed for the experiment study of the humanoid wrist/shoulder joint. And the dynamic model of the mechanism is formulated by using the coupling theory of the flexible body’s large global motion and small flexible deformation. Based on derived dynamics, antivibration control of the joint robot is studied with a nonlinear control method. Finally, simulations and experiments were performed to validate the feasibility of the developed parallel robot prototype and the proposed control scheme.

Dynamics and Control of a Flexible Solar Sail

OpenAIRE

Jiafu Liu; Siyuan Rong; Fan Shen; Naigang Cui

2014-01-01

Solar sail can merely make use of solar radiation pressure (SRP) force as the thrust for space missions. The attitude dynamics is obtained for the highly flexible solar sail with control vanes, sliding masses, and a gimbaled control boom. The vibration equations are derived considering the geometric nonlinearity of the sail structure subjected to the forces generated by the control vanes, solar radiation pressure (SRP), and sliding masses. Then the dynamic models for attitude/vibration contr...

Synthesis of branched polymers under continuous-flow microprocess: an improvement of the control of macromolecular architectures.

Science.gov (United States)

Bally, Florence; Serra, Christophe A; Brochon, Cyril; Hadziioannou, Georges

2011-11-15

Polymerization reactions can benefit from continuous-flow microprocess in terms of kinetics control, reactants mixing or simply efficiency when high-throughput screening experiments are carried out. In this work, we perform for the first time the synthesis of branched macromolecular architecture through a controlled/'living' polymerization technique, in tubular microreactor. Just by tuning process parameters, such as flow rates of the reactants, we manage to generate a library of polymers with various macromolecular characteristics. Compared to conventional batch process, polymerization kinetics shows a faster initiation step and more interestingly an improved branching efficiency. Due to reduced diffusion pathway, a characteristic of microsystems, it is thus possible to reach branched polymers exhibiting a denser architecture, and potentially a higher functionality for later applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Power Control Flexibilities for Grid-Connected Multi-Functional Photovoltaic Inverters

DEFF Research Database (Denmark)

Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

2016-01-01

and intelligent services, such as fault ride-through and reactive power compensation, is the key to attain higher utilisation of solar PV energy. Such functionalities for the future PV inverters can contribute to reduced cost of energy, and thus enable more cost-effective PV installations. To implement...... the advanced features, a flexible power controller is developed in this study, which can be configured in the PV inverter and flexibly change from one to another mode during operation. Based on the single-phase PQ theory, the control strategy offers the possibilities to generate appropriate references...... for the inner current control loop. The references depend on system conditions and also specific demands from both system operators and prosumers. Besides, this power control strategy can be implemented in commercial PV inverters as a standardised function, and also the operation modes can be achieved online...

A Vibration Control Method for the Flexible Arm Based on Energy Migration

Directory of Open Access Journals (Sweden)

Yushu Bian

2015-01-01

Full Text Available A vibration control method based on energy migration is proposed to decrease vibration response of the flexible arm undergoing rigid motion. A type of vibration absorber is suggested and gives rise to the inertial coupling between the modes of the flexible arm and the absorber. By analyzing 1 : 2 internal resonance, it is proved that the internal resonance can be successfully created and the exchange of vibration energy is existent. Due to the inertial coupling, the damping enhancement effect is revealed. Via the inertial coupling, vibration energy of the flexible arm can be dissipated by not only the damping of the vibration absorber but also its own enhanced damping, thereby effectively decreasing vibration. Through numerical simulations and analyses, it is proven that this method is feasible in controlling nonlinear vibration of the flexible arm undergoing rigid motion.

Neurobiology: motor control of flexible octopus arms.

Science.gov (United States)

Sumbre, Germán; Fiorito, Graziano; Flash, Tamar; Hochner, Binyamin

2005-02-10

Animals with rigid skeletons can rely on several mechanisms to simplify motor control--for example, they have skeletal joints that reduce the number of variables and degrees of freedom that need to be controlled. Here we show that when the octopus uses one of its long and highly flexible arms to transfer an object from one place to another, it employs a vertebrate-like strategy, temporarily reconfiguring its arm into a stiffened, articulated, quasi-jointed structure. This indicates that an articulated limb may provide an optimal solution for achieving precise, point-to-point movements.

Control module and module for priority set-up for the CAMAC universal branch driver

International Nuclear Information System (INIS)

Nguen Fuk; Smirnov, V.A.

1976-01-01

Control module of BKD-871 universal branch driver operates as a controller in the control crate. This module performs synchronous data transmission to (from) the computer and shapes time signals for A-type controllers. The following regimes of data block transmission may be organized with the help of the control module: address scanning regime; repeated reference regime; stop regime. A priority driving module is required for organization of simultaneous operation from several control sources

Active Vibration Suppression of a 3-DOF Flexible Parallel Manipulator Using Efficient Modal Control

Directory of Open Access Journals (Sweden)

Quan Zhang

2014-01-01

Full Text Available This paper addresses the dynamic modeling and efficient modal control of a planar parallel manipulator (PPM with three flexible linkages actuated by linear ultrasonic motors (LUSM. To achieve active vibration control, multiple lead zirconate titanate (PZT transducers are mounted on the flexible links as vibration sensors and actuators. Based on Lagrange’s equations, the dynamic model of the flexible links is derived with the dynamics of PZT actuators incorporated. Using the assumed mode method (AMM, the elastic motion of the flexible links are discretized under the assumptions of pinned-free boundary conditions, and the assumed mode shapes are validated through experimental modal test. Efficient modal control (EMC, in which the feedback forces in different modes are determined according to the vibration amplitude or energy of their own, is employed to control the PZT actuators to realize active vibration suppression. Modal filters are developed to extract the modal displacements and velocities from the vibration sensors. Numerical simulation and vibration control experiments are conducted to verify the proposed dynamic model and controller. The results show that the EMC method has the capability of suppressing multimode vibration simultaneously, and both the structural and residual vibrations of the flexible links are effectively suppressed using EMC approach.

Dynamics and control of robotic spacecrafts for the transportation of flexible elements

International Nuclear Information System (INIS)

Wen, Hao; Chen, Ti; Yu, Bensong; Jin, Dongping

2016-01-01

The technology of robotic spacecrafts has been identified as one of the most appealing solutions to the on-orbit construction of large space structures in future space missions. As a prerequisite of a successful on-orbit construction, it is needed to use small autonomous spacecrafts for the transportation of flexible elements. To this end, the paper presents an energy-based scheme to control a couple of robotic spacecrafts carrying a flexible slender structure to its desired position. The flexible structure is modelled as a long beam based on the formulation of absolute nodal coordinates to account for the geometrical nonlinearity due to large displacement. Meanwhile, the robotic spacecrafts are actuated on their rigid-body degrees of freedom and modelled as two rigid bodies attached to the flexible beam. The energy-based controller is designed using the technique of energy shaping and damping injection such that translational and rotational maneuvers can be achieved with the suppression of the flexible vibrations of the beam. Finally, numerical case studies are performed to demonstrate the proposed schemes. (paper)

Design a Fuzzy Logic Controller for a Rotary Flexible Joint Robotic Arm

Directory of Open Access Journals (Sweden)

Jalani Jamaludin

2018-01-01

Full Text Available The purpose of this research is to design a fuzzy logic feedback controller (FLC in order to control a desired tip angle position a rotary flexible joint robotic arm. The FLC is also employed to dampen the vibration emanated from a rotary flexible joint robotic arm when reaching a desired tip angle position. The performance of FLC is tested in simulation and experiment. It is found that the FLC is successfully designed, applied and tested. The results show that fuzzy logic controller performed satisfactorily control a desired tip angle position and reduce the oscillations.

Abscisic acid signaling is controlled by a BRANCHED1/HD-ZIP I cascade in Arabidopsis axillary buds.

Science.gov (United States)

González-Grandío, Eduardo; Pajoro, Alice; Franco-Zorrilla, José M; Tarancón, Carlos; Immink, Richard G H; Cubas, Pilar

2017-01-10

Shoot-branching patterns determine key aspects of plant life and are important targets for crop breeding. However, we are still largely ignorant of the genetic networks controlling locally the most important decision during branch development: whether the axillary bud, or branch primordium, grows out to give a lateral shoot or remains dormant. Here we show that, inside the buds, the TEOSINTE BRANCHED1, CYCLOIDEA, PCF (TCP) transcription factor BRANCHED1 (BRC1) binds to and positively regulates the transcription of three related Homeodomain leucine zipper protein (HD-ZIP)-encoding genes: HOMEOBOX PROTEIN 21 (HB21), HOMEOBOX PROTEIN 40 (HB40), and HOMEOBOX PROTEIN 53 (HB53). These three genes, together with BRC1, enhance 9-CIS-EPOXICAROTENOID DIOXIGENASE 3 (NCED3) expression, lead to abscisic acid accumulation, and trigger hormone response, thus causing suppression of bud development. This TCP/HD-ZIP genetic module seems to be conserved in dicot and monocotyledonous species to prevent branching under light-limiting conditions.

Adaptive precompensators for flexible-link manipulator control

Science.gov (United States)

Tzes, Anthony P.; Yurkovich, Stephen

1989-01-01

The application of input precompensators to flexible manipulators is considered. Frequency domain compensators color the input around the flexible mode locations, resulting in a bandstop or notch filter in cascade with the system. Time domain compensators apply a sequence of impulses at prespecified times related to the modal frequencies. The resulting control corresponds to a feedforward term that convolves in real-time the desired reference input with a sequence of impulses and produces a vibration-free output. An adaptive precompensator can be implemented by combining a frequency domain identification scheme which is used to estimate online the modal frequencies and subsequently update the bandstop interval or the spacing between the impulses. The combined adaptive input preshaping scheme provides the most rapid slew that results in a vibration-free output. Experimental results are presented to verify the results.

Experimental studies of control concepts for a parallel manipulator with flexible links

International Nuclear Information System (INIS)

Burkhardt, Markus; Eberhard, Peter; Seifried, Robert

2015-01-01

Control of flexible multibody systems, such as flexible manipulators, is a challenging task. This is especially true if end-effector trajectory tracking is aspired. On the one hand, these systems require a large number of generalized coordinates to describe their dynamical behavior accurately. On the other hand, only a small subset of these values can be measured or reconstructed on-the-fly. Hence, it is difficult, if not nearly impossible, to use a state controller. In addition, flexible systems are under actuated, i.e. they possess less control inputs than generalized coordinates. In case of a non-collocated output controller, which is the case for end-effector trajectory tracking, the closed loop of the system might lose passivity and is non-minimum phase. In order to achieve end-effector trajectory tracking, exact and approximate feed-forward controls can be applied. In this work, two different versions of such concepts are compared experimentally. These model-based concepts are computed off-line and they supply, next to the required input values, a C1 -continuous solution of the complete state vector which can be used for feedback control. If the system is non-minimum phase, a two-sided boundary value problem has to be solved and the solution includes a pre-actuation as well as a post-actuation phase. While the exact method incorporates all dynamical effects of the flexible multibody system, the approximate concepts neglect certain implications, for example the dynamical effects due to the flexibility. In addition to the presentation of the theoretical basics of the control approaches and the underlying models, this contribution addresses some of the crucial obstacles, which have to be overcome for the operation of the test bench, e.g., signal conditioning, state reconstruction and friction compensation. Since the installed sensors do not allow the direct measurement of the end effector position, image tracking is used to judge the quality of the different

Modeling and control of a hydraulically actuated flexible-prismatic link robot

International Nuclear Information System (INIS)

Love, L.; Kress, R.; Jansen, J.

1996-12-01

Most of the research related to flexible link manipulators to date has focused on single link, fixed length, single plane of vibration test beds. In addition, actuation has been predominantly based upon electromagnetic motors. Ironically, these elements are rarely found in the existing industrial long reach systems. This manuscript describes a new hydraulically actuated, long reach manipulator with a flexible prismatic link at Oak Ridge National Laboratory (ORNL). Focus is directed towards both modeling and control of hydraulic actuators as well as flexible links that have variable natural frequencies

Environmental Control of Branching in Petunia1[OPEN

Science.gov (United States)

Oplaat, Carla; Wohlers, Mark W.

2015-01-01

Plants alter their development in response to changes in their environment. This responsiveness has proven to be a successful evolutionary trait. Here, we tested the hypothesis that two key environmental factors, light and nutrition, are integrated within the axillary bud to promote or suppress the growth of the bud into a branch. Using petunia (Petunia hybrida) as a model for vegetative branching, we manipulated both light quality (as crowding and the red-to-far-red light ratio) and phosphate availability, such that the axillary bud at node 7 varied from deeply dormant to rapidly growing. In conjunction with the phenotypic characterization, we also monitored the state of the strigolactone (SL) pathway by quantifying SL-related gene transcripts. Mutants in the SL pathway inhibit but do not abolish the branching response to these environmental signals, and neither signal is dominant over the other, suggesting that the regulation of branching in response to the environment is complex. We have isolated three new putatively SL-related TCP (for Teosinte branched1, Cycloidia, and Proliferating cell factor) genes from petunia, and have identified that these TCP-type transcription factors may have roles in the SL signaling pathway both before and after the reception of the SL signal at the bud. We show that the abundance of the receptor transcript is regulated by light quality, such that axillary buds growing in added far-red light have greatly increased receptor transcript abundance. This suggests a mechanism whereby the impact of any SL signal reaching an axillary bud is modulated by the responsiveness of these cells to the signal. PMID:25911529

Control of flexible robots with prismatic joints and hydraulic drives

International Nuclear Information System (INIS)

Love, L.J.; Kress, R.L.; Jansen, J.F.

1997-01-01

The design and control of long-reach, flexible manipulators has been an active research topic for over 20 years. Most of the research to date has focused on single link, fixed length, single plane of vibration test beds. In addition, actuation has been predominantly based upon electromagnetic motors. Ironically, these elements are rarely found in the existing industrial long-reach systems. One example is the Modified Light Duty Utility Arm (MLDUA) designed and built by Spar Aerospace for Oak Ridge National Laboratory (ORNL). This arm operates in larger, underground waste storage tanks located at ORNL. The size and nature of the tanks require that the robot have a reach of approximately 15 ft and a payload capacity of 250 lb. In order to achieve these criteria, each joint is hydraulically actuated. Furthermore, the robot has a prismatic degree-of-freedom to ease deployment. When fully extended, the robot's first natural frequency is 1.76 Hz. Many of the projected tasks, coupled with the robot's flexibility, present an interesting problem. How will many of the existing flexure control algorithms perform on a hydraulic, long-reach manipulator with prismatic links? To minimize cost and risk of testing these algorithms on the MLDUA, the authors have designed a new test bed that contains many of the same elements. This manuscript described a new hydraulically actuated, long-reach manipulator with a flexible prismatic link at ORNL. Focus is directed toward both modeling and control of hydraulic actuators as well as flexible links that have variable natural frequencies

Attitude tracking control of flexible spacecraft with large amplitude slosh

Science.gov (United States)

Deng, Mingle; Yue, Baozeng

2017-12-01

This paper is focused on attitude tracking control of a spacecraft that is equipped with flexible appendage and partially filled liquid propellant tank. The large amplitude liquid slosh is included by using a moving pulsating ball model that is further improved to estimate the settling location of liquid in microgravity or a zero-g environment. The flexible appendage is modelled as a three-dimensional Bernoulli-Euler beam, and the assumed modal method is employed. A hybrid controller that combines sliding mode control with an adaptive algorithm is designed for spacecraft to perform attitude tracking. The proposed controller has proved to be asymptotically stable. A nonlinear model for the overall coupled system including spacecraft attitude dynamics, liquid slosh, structural vibration and control action is established. Numerical simulation results are presented to show the dynamic behaviors of the coupled system and to verify the effectiveness of the control approach when the spacecraft undergoes the disturbance produced by large amplitude slosh and appendage vibration. Lastly, the designed adaptive algorithm is found to be effective to improve the precision of attitude tracking.

Vibration Control of Flexible Mode for a Beam-Type Substrate Transport Robot

Directory of Open Access Journals (Sweden)

Cheol Hoon Park

2013-07-01

Full Text Available Beam-type substrate transport robots are widely used to handle substrates, especially in the solar cell manufacturing process. To reduce the takt time and increase productivity, accurate position control becomes increasingly important as the size of the substrate increases. However, the vibration caused by the flexible forks in beam-type robots interferes with accurate positioning, which results in long takt times in the manufacturing process. To minimize the vibration and transport substrates on the fork as fast as possible, the trajectories should be prevented from exciting the flexible modes of the forks. For this purpose, a fifth-order polynomial trajectory generator and input shaping were incorporated into the controller of the beam-type robot in this study. The flexible modes of the forks were identified by measuring the frequency response function (FRF, and the input shaping was designed so as not to excite the flexible modes. The controller was implemented by using MATLAB/xPC Target. In this paper, the design procedure of input shaping and its effectiveness for vibration attenuation in both “no load” and “load” cases is presented.

INCAP - Applying short-term flexibility to control inventories

OpenAIRE

Lödding , Hermann; Lohmann , Steffen

2011-01-01

Abstract Inventory Based Capacity Control (INCAP) is a very simple method that allows inventory levels to be effectively controlled by using short-term capacity flexibility in make-to-stock settings. Moreover, INCAP can be used for finished goods inventories as well as for semi-finished goods inventories. The basic idea is to define upper and lower inventory limits and to adjust capacities if the inventory level reaches either limit. Should the inventory fall below the lower limit,...

Flexible structure control experiments using a real-time workstation for computer-aided control engineering

Science.gov (United States)

Stieber, Michael E.

1989-01-01

A Real-Time Workstation for Computer-Aided Control Engineering has been developed jointly by the Communications Research Centre (CRC) and Ruhr-Universitaet Bochum (RUB), West Germany. The system is presently used for the development and experimental verification of control techniques for large space systems with significant structural flexibility. The Real-Time Workstation essentially is an implementation of RUB's extensive Computer-Aided Control Engineering package KEDDC on an INTEL micro-computer running under the RMS real-time operating system. The portable system supports system identification, analysis, control design and simulation, as well as the immediate implementation and test of control systems. The Real-Time Workstation is currently being used by CRC to study control/structure interaction on a ground-based structure called DAISY, whose design was inspired by a reflector antenna. DAISY emulates the dynamics of a large flexible spacecraft with the following characteristics: rigid body modes, many clustered vibration modes with low frequencies and extremely low damping. The Real-Time Workstation was found to be a very powerful tool for experimental studies, supporting control design and simulation, and conducting and evaluating tests withn one integrated environment.

Coordination and Control of Flexible Building Loads for Renewable Integration; Demonstrations using VOLTTRON

Energy Technology Data Exchange (ETDEWEB)

Hao, He [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liu, Guopeng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Sen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Katipamula, Srinivas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-10-31

Renewable energy resources such as wind and solar power have a high degree of uncertainty. Large-scale integration of these variable generation sources into the grid is a big challenge for power system operators. Buildings, in which we live and work, consume about 75% of the total electricity in the United States. They also have a large capacity of power flexibility due to their massive thermal capacitance. Therefore, they present a great opportunity to help the grid to manage power balance. In this report, we study coordination and control of flexible building loads for renewable integration. We first present the motivation and background, and conduct a literature review on building-to-grid integration. We also compile a catalog of flexible building loads that have great potential for renewable integration, and discuss their characteristics. We next collect solar generation data from a photovoltaic panel on Pacific Northwest National Laboratory campus, and conduct data analysis to study their characteristics. We find that solar generation output has a strong uncertainty, and the uncertainty occurs at almost all time scales. Additional data from other sources are also used to verify our study. We propose two transactive coordination strategies to manage flexible building loads for renewable integration. We prove the theories that support the two transactive coordination strategies and discuss their pros and cons. In this report, we select three types of flexible building loads—air-handling unit, rooftop unit, and a population of WHs—for which we demonstrate control of the flexible load to track a dispatch signal (e.g., renewable generation fluctuation) using experiment, simulation, or hardware-in-the-loop study. More specifically, we present the system description, model identification, controller design, test bed setup, and experiment results for each demonstration. We show that coordination and control of flexible loads has a great potential to integrate

Feedback tracking control for dynamic morphing of piezocomposite actuated flexible wings

Science.gov (United States)

Wang, Xiaoming; Zhou, Wenya; Wu, Zhigang

2018-03-01

Aerodynamic properties of flexible wings can be improved via shape morphing using piezocomposite materials. Dynamic shape control of flexible wings is investigated in this study by considering the interactions between structural dynamics, unsteady aerodynamics and piezo-actuations. A novel antisymmetric angle-ply bimorph configuration of piezocomposite actuators is presented to realize coupled bending-torsional shape control. The active aeroelastic model is derived using finite element method and Theodorsen unsteady aerodynamic loads. A time-varying linear quadratic Gaussian (LQG) tracking control system is designed to enhance aerodynamic lift with pre-defined trajectories. Proof-of-concept simulations of static and dynamic shape control are presented for a scaled high-aspect-ratio wing model. Vibrations of the wing and fluctuations in aerodynamic forces are caused by using the static voltages directly in dynamic shape control. The lift response has tracked the trajectories well with favorable dynamic morphing performance via feedback tracking control.

Development of a modular integrated control architecture for flexible manipulators. Final report

International Nuclear Information System (INIS)

Burks, B.L.; Battiston, G.

1994-01-01

In April 1994, ORNL and SPAR completed the joint development of a manipulator controls architecture for flexible structure controls under a CRADA between the two organizations. The CRADA project entailed design and development of a new architecture based upon the Modular Integrated Control Architecture (MICA) previously developed by ORNL. The new architecture, dubbed MICA-II, uses an object-oriented coding philosophy to provide a highly modular and expandable architecture for robotic manipulator control. This architecture can be readily ported to control of many different manipulator systems. The controller also provides a user friendly graphical operator interface and display of many forms of data including system diagnostics. The capabilities of MICA-II were demonstrated during oscillation damping experiments using the Flexible Beam Experimental Test Bed at Hanford

Model of rotary-actuated flexible beam with notch filter vibration suppression controller and torque feedforward load compensation controller

International Nuclear Information System (INIS)

Bills, K.C.; Kress, R.L.; Kwon, D.S.; Baker, C.P.

1994-01-01

This paper describes ORNL's development of an environment for the simulation of robotic manipulators. Simulation includes the modeling of kinematics, dynamics, sensors, actuators, control systems, operators, and environments. Models will be used for manipulator design, proposal evaluation, control system design and analysis, graphical preview of proposed motions, safety system development, and training. Of particular interest is the development of models for robotic manipulators having at least one flexible link. As a first application, models have been developed for the Pacific Northwest Laboratory's Flexible Beam Test Bed (PNL FBTB), which is a 1-Degree-of-Freedom, flexible arm with a hydraulic base actuator. ORNL transferred control algorithms developed for the PNL FBTB to controlling IGRIP models. A robust notch filter is running in IGRIP controlling a full dynamics model of the PNL test bed. Model results provide a reasonable match to the experimental results (quantitative results are being determined) and can run on ORNL's Onyx machine in approximately realtime. The flexible beam is modeled as six rigid sections with torsional springs between each segment. The spring constants were adjusted to match the physical response of the flexible beam model to the experimental results. The controller is able to improve performance on the model similar to the improvement seen on the experimental system. Some differences are apparent, most notably because the IGRIP model presently uses a different trajectory planner than the one used by ORNL on the PNL test bed. In the future, the trajectory planner will be modified so that the experiments and models are the same. The successful completion of this work provides the ability to link C code with IGRIP, thus allowing controllers to be developed, tested, and tuned in simulation and then ported directly to hardware systems using the C language

Efficient industrial burner control of a flexible burner management system; Effiziente industrielle Brennertechnik durch Einsatz flexibler Feuerungsautomaten

Energy Technology Data Exchange (ETDEWEB)

Hofmann, Ulrich; Saenger, Peter [Siemens AG, Rastatt (Germany)

2012-02-15

Compactness and flexibility of a burner control system is a very important issue. With a few types a wide range in different industrial applications should be covered. This paper presents different applications of a new burner control system: heating of cooling lines in glass industry, steam generation and air heating for a pistachio roastery and in grain dryers. (orig.)

Technical normalization in the geoinformatics branch

Directory of Open Access Journals (Sweden)

Bronislava Horáková

2006-09-01

Full Text Available A basic principle of the technical normalisation is to hold the market development by developing unified technical rules for all concerned subjects. The information and communication technological industry is characterised by certain specific features contrary to the traditional industry. These features bring to the normalisation domain new demands, mainly the flexibility enabling to reflect the rapidly development market of ICT elastic way. The goal of the paper is to provide a comprehensive overview of the current process of technical normalization in the geoinformatic branch

Optimum Aggregation and Control of Spatially Distributed Flexible Resources in Smart Grid

DEFF Research Database (Denmark)

Bhattarai, Bishnu Prasad; Mendaza, Iker Diaz de Cerio; Myers, Kurt S.

2018-01-01

system operators (DSOs) to make faster operational decisions. Moreover, the aggregation enables flexibility from small distributed flexible resources to be traded to different power and energy markets. A hierarchical control architecture comprising a combination of centralized and decentralized control...... is demonstrated through simulation of three operational scenarios in a real low voltage distribution system having high penetrations of electric vehicles and heat pumps. The simulation results demonstrated that the aggregation helps DSOs not only in taking faster operational decisions, but also in effectively...

Designing flexible, ''chemist-friendly'' software to control a radiochemistry autosynthesizer

International Nuclear Information System (INIS)

Feliu, A.L.

1989-01-01

To enhance the utility of process control software to control radiochemistry autosynthesizers used with short-lived positron-emitting isotopes, a scheme is proposed by which routine executive-level tasks, hardware control operations, and chemical procedures have been segregated. This strategy can lead to chemist-friendly control programs for any desired hardware configuration, as illustrated in new software designed to exploit the features and flexibility of the CTI/Siemens Chemical Process Control Unit. (author)

Multi-level Control Framework for Enhanced Flexibility of Active Distribution Network

DEFF Research Database (Denmark)

Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

2017-01-01

In this paper, the control objectives of future active distribution networks with high penetration of renewables and flexible loads are analyzed and reviewed. From a state of the art review, the important control objectives seen from the perspective of a distribution system operator are identifie......-ordination and management of the network assets at different voltage levels and geographical locations. The paper finally shows the applicability of the multi-level control architecture to some of the key challenges in the distribution system operation by relevant scenarios....... to be hosting capacity improvement, high reliable operation and cost effective network management. Based on this review and a state of the art review concerning future distribution network control methods, a multi-level control architecture is constructed for an active distribution network, which satisfies...... the selected control objectives and provides enhanced flexibility. The control architecture is supported by generation/load forecasting and distribution state estimation techniques to improve the controllability of the network. The multi-level control architecture consists of three levels of hierarchical...

To increase controllability of a large flexible antenna by modal optimization

Science.gov (United States)

Wang, Feng; Wang, Pengpeng; Jiang, Wenjian

2017-12-01

Large deployable antennas are widely used in aerospace engineering to meet the envelop limit of rocket fairing. The high flexibility and low damping of antenna has proposed critical requirement not only for stability control of the antenna itself, but also for attitude control of the satellite. This paper aims to increase controllability of a large flexible antenna by modal optimization. Firstly, Sensitivity analysis of antenna modal frequencies to stiffness of support structure and stiffness of scanning mechanism are conducted respectively. Secondly, Modal simulation results of antenna frequencies are given, influences of scanning angles on moment of inertia and modal frequencies are evaluated, and modal test is carried out to validate the simulation results. All the simulation and test results show that, after modal optimization the modal characteristic of the large deployable antenna meets the controllability requirement well.

Walking Flexibility after Hemispherectomy: Split-Belt Treadmill Adaptation and Feedback Control

Science.gov (United States)

Choi, Julia T.; Vining, Eileen P. G.; Reisman, Darcy S.; Bastian, Amy J.

2009-01-01

Walking flexibility depends on use of feedback or reactive control to respond to unexpected changes in the environment, and the ability to adapt feedforward or predictive control for sustained alterations. Recent work has demonstrated that cerebellar damage impairs feedforward adaptation, but not feedback control, during human split-belt treadmill…

The effects of the Bowen technique on hamstring flexibility over time: a randomised controlled trial.

Science.gov (United States)

Marr, Michelle; Baker, Julian; Lambon, Nicky; Perry, Jo

2011-07-01

The hamstring muscles are regularly implicated in recurrent injuries, movement dysfunction and low back pain. Links between limited flexibility and development of neuromusculoskeletal symptoms are frequently reported. The Bowen Technique is used to treat many conditions including lack of flexibility. The study set out to investigate the effect of the Bowen Technique on hamstring flexibility over time. An assessor-blind, prospective, randomised controlled trial was performed on 120 asymptomatic volunteers. Participants were randomly allocated into a control group or Bowen group. Three flexibility measurements occurred over one week, using an active knee extension test. The intervention group received a single Bowen treatment. A repeated measures univariate analysis of variance, across both groups for the three time periods, revealed significant within-subject and between-subject differences for the Bowen group. Continuing increases in flexibility levels were observed over one week. No significant change over time was noted for the control group. Copyright © 2010 Elsevier Ltd. All rights reserved.

Flexible and Safe Control of Mobile Surface Systems, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The primary innovation of this work is a novel approach for flexible and safe control of highly capable mobile surface systems, such as long-duration science rovers,...

Tool position tracking control of a nonlinear uncertain flexible robot ...

Indian Academy of Sciences (India)

Moreover, other different papers and thesis of flexible manipulators ... various applications is highly sensitive to variations of disturbance torque acting on ...... Dang X 2014 Robust adaptive sliding-mode control of condenser-cleaning mobile.

Numerical and Experimental Modal Control of Flexible Rotor Using Electromagnetic Actuator

Directory of Open Access Journals (Sweden)

Edson Hideki Koroishi

2014-01-01

Full Text Available The present work is dedicated to active modal control applied to flexible rotors. The effectiveness of the corresponding techniques for controlling a flexible rotor is tested numerically and experimentally. Two different approaches are used to determine the appropriate controllers. The first uses the linear quadratic regulator and the second approach is the fuzzy modal control. This paper is focused on the electromagnetic actuator, which in this case is part of a hybrid bearing. Due to numerical reasons it was necessary to reduce the size of the model of the rotating system so that the design of the controllers and estimator could be performed. The role of the Kalman estimator in the present contribution is to estimate the modal states of the system and to determine the displacement of the rotor at the position of the hybrid bearing. Finally, numerical and experimental results demonstrate the success of the methodology conveyed.

Flexible and Safe Control of Mobile Surface Systems, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The primary innovation of this work is a novel Petri net based approach for safe and flexible control of highly capable mobile surface systems, such as long-duration...

Synchronizing tracking control for flexible joint robots via estimated state feedback

NARCIS (Netherlands)

Rodriguez Angeles, A.; Nijmeijer, H.

2004-01-01

In this paper, we propose a synchronization controller for flexible joint robots, which are interconnected in a master-slave scheme. The synchronization controller is based on feedback linearization and only requires measurements of the master and slave link positions, since the velocities and

Modern Control Design for Flexible Wind Turbines

Energy Technology Data Exchange (ETDEWEB)

Wright, A. D.

2004-07-01

Control can improve energy capture and reduce dynamic loads in wind turbines. In the 1970s and 1980s, wind turbines used classical control designs to regulate power and speed. The methods used, however, were not always successful. Modern turbines are larger, mounted on taller towers, and more dynamically active than their predecessors. Control systems to regulate turbine power and maintain stable, closed-loop behavior in the presence of turbulent wind inflow will be critical for these designs. This report applies modern state-space control design methods to a two-bladed teetering hub upwind machine at the National Wind Technology Center (NWTC), which is managed by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado. The design objective is to regulate turbine speed and enhance damping in several low-damped flexible modes of the turbine. Starting with simple control algorithms based on linear models, complexity is added incrementally until the desired performance is firmly established.

Intelligent controller of a flexible hybrid robot machine for ITER assembly and maintenance

International Nuclear Information System (INIS)

Al-saedi, Mazin I.; Wu, Huapeng; Handroos, Heikki

2014-01-01

Highlights: • Studying flexible multibody dynamic of hybrid parallel robot. • Investigating fuzzy-PD controller to control a hybrid flexible hydraulically driven robot. • Investigating ANFIS-PD controller to control a hybrid flexible robot. Compare to traditional PID this method gives better performance. • Using the equilibrium of reaction forces between the parallel and serial parts of hybrid robot to control the serial part hydraulically driven. - Abstract: The assembly and maintenance of International Thermonuclear Experimental Reactor (ITER) vacuum vessel (VV) is highly challenging since the tasks performed by the robot involve welding, material handling, and machine cutting from inside the VV. To fulfill the tasks in ITER application, this paper presents a hybrid redundant manipulator with four DOFs provided by serial kinematic axes and six DOFs by parallel mechanism. Thus, in machining, to achieve greater end-effector trajectory tracking accuracy for surface quality, a robust control of the actuators for the flexible link has to be deduced. In this paper, the intelligent control of a hydraulically driven parallel robot part based on the dynamic model and two control schemes have been investigated: (1) fuzzy-PID self tuning controller composed of the conventional PID control and with fuzzy logic; (2) adaptive neuro-fuzzy inference system-PID (ANFIS-PID) self tuning of the gains of the PID controller, which are implemented independently to control each hydraulic cylinder of the parallel robot based on rod position predictions. The obtained results of the fuzzy-PID and ANFIS-PID self tuning controller can reduce more tracking errors than the conventional PID controller. Subsequently, the serial component of the hybrid robot can be analyzed using the equilibrium of reaction forces at the universal joint connections of the hexa-element. To achieve precise positional control of the end effector for maximum precision machining, the hydraulic cylinder should

Intelligent controller of a flexible hybrid robot machine for ITER assembly and maintenance

Energy Technology Data Exchange (ETDEWEB)

Al-saedi, Mazin I., E-mail: mazin.al-saedi@lut.fi; Wu, Huapeng; Handroos, Heikki

2014-10-15

Highlights: • Studying flexible multibody dynamic of hybrid parallel robot. • Investigating fuzzy-PD controller to control a hybrid flexible hydraulically driven robot. • Investigating ANFIS-PD controller to control a hybrid flexible robot. Compare to traditional PID this method gives better performance. • Using the equilibrium of reaction forces between the parallel and serial parts of hybrid robot to control the serial part hydraulically driven. - Abstract: The assembly and maintenance of International Thermonuclear Experimental Reactor (ITER) vacuum vessel (VV) is highly challenging since the tasks performed by the robot involve welding, material handling, and machine cutting from inside the VV. To fulfill the tasks in ITER application, this paper presents a hybrid redundant manipulator with four DOFs provided by serial kinematic axes and six DOFs by parallel mechanism. Thus, in machining, to achieve greater end-effector trajectory tracking accuracy for surface quality, a robust control of the actuators for the flexible link has to be deduced. In this paper, the intelligent control of a hydraulically driven parallel robot part based on the dynamic model and two control schemes have been investigated: (1) fuzzy-PID self tuning controller composed of the conventional PID control and with fuzzy logic; (2) adaptive neuro-fuzzy inference system-PID (ANFIS-PID) self tuning of the gains of the PID controller, which are implemented independently to control each hydraulic cylinder of the parallel robot based on rod position predictions. The obtained results of the fuzzy-PID and ANFIS-PID self tuning controller can reduce more tracking errors than the conventional PID controller. Subsequently, the serial component of the hybrid robot can be analyzed using the equilibrium of reaction forces at the universal joint connections of the hexa-element. To achieve precise positional control of the end effector for maximum precision machining, the hydraulic cylinder should

Design of Control System for Flexible Packaging Bags Palletizing Production Line Based on PLC

Science.gov (United States)

Zheng, Huiping; Chen, Lin; Zhao, Xiaoming; Liu, Zhanyang

Flexible packaging bags palletizing production line is to put the bags in the required area according to particular order and size, in order to finish handling, storage, loading and unloading, transportation and other logistics work of goods. Flexible packaging bags palletizing line is composed of turning bags mechanism, shaping mechanism, indexing mechanism, marshalling mechanism, pushing bags mechanism, pressing bags mechanism, laminating mechanism, elevator, tray warehouse, tray conveyor and loaded tray conveyor. Whether the whole production line can smoothly run depends on each of the above equipment and precision control among them. In this paper the technological process and the control logic of flexible packaging bags palletizing production line is introduced. Palletizing process of the production line realized automation by means of a control system based on programmable logic controller (PLC). It has the advantages of simple structure, reliable and easy maintenance etc.

Design of a Compact Actuation and Control System for Flexible Medical Robots.

Science.gov (United States)

Morimoto, Tania K; Hawkes, Elliot Wright; Okamura, Allison M

2017-07-01

Flexible medical robots can improve surgical procedures by decreasing invasiveness and increasing accessibility within the body. Using preoperative images, these robots can be designed to optimize a procedure for a particular patient. To minimize invasiveness and maximize biocompatibility, the actuation units of flexible medical robots should be placed fully outside the patient's body. In this letter, we present a novel, compact, lightweight, modular actuation, and control system for driving a class of these flexible robots, known as concentric tube robots. A key feature of the design is the use of three-dimensional printed waffle gears to enable compact control of two degrees of freedom within each module. We measure the precision and accuracy of a single actuation module and demonstrate the ability of an integrated set of three actuation modules to control six degrees of freedom. The integrated system drives a three-tube concentric tube robot to reach a final tip position that is on average less than 2 mm from a given target. In addition, we show a handheld manifestation of the device and present its potential applications.

Turing mechanism underlying a branching model for lung morphogenesis.

Science.gov (United States)

Xu, Hui; Sun, Mingzhu; Zhao, Xin

2017-01-01

The mammalian lung develops through branching morphogenesis. Two primary forms of branching, which occur in order, in the lung have been identified: tip bifurcation and side branching. However, the mechanisms of lung branching morphogenesis remain to be explored. In our previous study, a biological mechanism was presented for lung branching pattern formation through a branching model. Here, we provide a mathematical mechanism underlying the branching patterns. By decoupling the branching model, we demonstrated the existence of Turing instability. We performed Turing instability analysis to reveal the mathematical mechanism of the branching patterns. Our simulation results show that the Turing patterns underlying the branching patterns are spot patterns that exhibit high local morphogen concentration. The high local morphogen concentration induces the growth of branching. Furthermore, we found that the sparse spot patterns underlie the tip bifurcation patterns, while the dense spot patterns underlies the side branching patterns. The dispersion relation analysis shows that the Turing wavelength affects the branching structure. As the wavelength decreases, the spot patterns change from sparse to dense, the rate of tip bifurcation decreases and side branching eventually occurs instead. In the process of transformation, there may exists hybrid branching that mixes tip bifurcation and side branching. Since experimental studies have reported that branching mode switching from side branching to tip bifurcation in the lung is under genetic control, our simulation results suggest that genes control the switch of the branching mode by regulating the Turing wavelength. Our results provide a novel insight into and understanding of the formation of branching patterns in the lung and other biological systems.

COMPUTER SIMULATION OF LOCAL MOBILITY IN DENDRIMERS WITH ASYMMETRIC BRANCHING BY BROWNIAN DYNAMICS METHOD

Directory of Open Access Journals (Sweden)

O. V. Shavykin

2016-09-01

Full Text Available The Brownian dynamics method has been used to study the effect of the branching asymmetry on the local orientational mobility of segments and bonds in dendrimers in good solvent. “Coarse-grained” models of flexible dendrimers with different branching symmetry but with the same average segment length were considered. The frequency dependences of the rate of the spin-lattice relaxation nuclear magnetic resonance (NMR [1/T1H(H] for segments or bonds located at different distances from terminal monomers were calculated. After the exclusion of the contribution of the overall dendrimer rotation the position of the maxima of the frequency dependences [1/T1H(ωH] for different segments with the same length doesn’t depend on their location inside a dendrimer both for phantom models and for models with excluded volume interactions. This effect doesn’t depend also on the branching symmetry, but the position of the maximum [1/T1H(ωH] is determined by the segment length. For bonds inside segments the positions of the maximum [1/T1H(ωH] coincide for all models considered. Therefore, the obtained earlier conclusion about the weak influence of the excluded volume interactions on the local dynamics in the flexible symmetric dendrimers can be generalized for dendrimers with an asymmetric branching.

Tool position tracking control of a nonlinear uncertain flexible robot ...

Indian Academy of Sciences (India)

Robot manipulators have become progressively important in the field of flexible ... this research, tracking of tool position and minimization of motor torque are ...... and Menhaj M B 2013a Position and current control of a permanent-magnet syn-.

Stability Result For Dynamic Inversion Devised to Control Large Flexible Aircraft

Science.gov (United States)

Gregory, Irene M.

2001-01-01

High performance aircraft of the future will be designed lighter, more maneuverable, and operate over an ever expanding flight envelope. One of the largest differences from the flight control perspective between current and future advanced aircraft is elasticity. Over the last decade, dynamic inversion methodology has gained considerable popularity in application to highly maneuverable fighter aircraft, which were treated as rigid vehicles. This paper is an initial attempt to establish global stability results for dynamic inversion methodology as applied to a large, flexible aircraft. This work builds on a previous result for rigid fighter aircraft and adds a new level of complexity that is the flexible aircraft dynamics, which cannot be ignored even in the most basic flight control. The results arise from observations of the control laws designed for a new generation of the High-Speed Civil Transport aircraft.

Applying Student Team Achievement Divisions (STAD) Model on Material of Basic Programme Branch Control Structure to Increase Activity and Student Result

Science.gov (United States)

Akhrian Syahidi, Aulia; Asyikin, Arifin Noor; Asy’ari

2018-04-01

Based on my experience of teaching the material of branch control structure, it is found that the condition of the students is less active causing the low activity of the students on the attitude assessment during the learning process on the material of the branch control structure i.e. 2 students 6.45% percentage of good activity and 29 students percentage 93.55% enough and less activity. Then from the low activity resulted in low student learning outcomes based on a daily re-examination of branch control material, only 8 students 26% percentage reached KKM and 23 students 74% percent did not reach KKM. The purpose of this research is to increase the activity and learning outcomes of students of class X TKJ B SMK Muhammadiyah 1 Banjarmasin after applying STAD type cooperative learning model on the material of branch control structure. The research method used is Classroom Action Research. The study was conducted two cycles with six meetings. The subjects of this study were students of class X TKJ B with a total of 31 students consisting of 23 men and 8 women. The object of this study is the activity and student learning outcomes. Data collection techniques used are test and observation techniques. Data analysis technique used is a percentage and mean. The results of this study indicate that: an increase in activity and learning outcomes of students on the basic programming learning material branch control structure after applying STAD type cooperative learning model.

Modelling and Control of the Multi-Stage Cable Pulley-Driven Flexible-Joint Robot

Directory of Open Access Journals (Sweden)

Phongsaen Pitakwatchara

2014-07-01

Full Text Available This work is concerned with the task space impedance control of a robot driven through a multi-stage nonlinear flexible transmission system. Specifically, a two degrees-of-freedom cable pulley-driven flexible-joint robot is considered. Realistic modelling of the system is developed within the bond graph modelling framework. The model captures the nonlinear compliance behaviour of the multi-stage cable pulley transmission system, the spring effect of the augmented counterbalancing mechanism, the major loss throughout the system elements, and the typical inertial dynamics of the robot. Next, a task space impedance controller based on limited information about the angle and the current of the motors is designed. The motor current is used to infer the transmitted torque, by which the motor inertia may be modulated. The motor angle is employed to estimate the stationary distal robot link angle and the robot joint velocity. They are used in the controller to generate the desired damping force and to shape the potential energy of the flexible joint robot system to the desired configuration. Simulation and experimental results of the controlled system signify the competency of the proposed control law.

Multi-Time Scale Control of Demand Flexibility in Smart Distribution Networks

Directory of Open Access Journals (Sweden)

Bishnu P. Bhattarai

2017-01-01

Full Text Available This paper presents a multi-timescale control strategy to deploy electric vehicle (EV demand flexibility for simultaneously providing power balancing, grid congestion management, and economic benefits to participating actors. First, an EV charging problem is investigated from consumer, aggregator, and distribution system operator’s perspectives. A hierarchical control architecture (HCA comprising scheduling, coordinative, and adaptive layers is then designed to realize their coordinative goal. This is realized by integrating multi-time scale controls that work from a day-ahead scheduling up to real-time adaptive control. The performance of the developed method is investigated with high EV penetration in a typical residential distribution grid. The simulation results demonstrate that HCA efficiently utilizes demand flexibility stemming from EVs to solve grid unbalancing and congestions with simultaneous maximization of economic benefits to the participating actors. This is ensured by enabling EV participation in day-ahead, balancing, and regulation markets. For the given network configuration and pricing structure, HCA ensures the EV owners to get paid up to five times the cost they were paying without control.

Dynamic modeling and hierarchical compound control of a novel 2-DOF flexible parallel manipulator with multiple actuation modes

Science.gov (United States)

Liang, Dong; Song, Yimin; Sun, Tao; Jin, Xueying

2018-03-01

This paper addresses the problem of rigid-flexible coupling dynamic modeling and active control of a novel flexible parallel manipulator (PM) with multiple actuation modes. Firstly, based on the flexible multi-body dynamics theory, the rigid-flexible coupling dynamic model (RFDM) of system is developed by virtue of the augmented Lagrangian multipliers approach. For completeness, the mathematical models of permanent magnet synchronous motor (PMSM) and piezoelectric transducer (PZT) are further established and integrated with the RFDM of mechanical system to formulate the electromechanical coupling dynamic model (ECDM). To achieve the trajectory tracking and vibration suppression, a hierarchical compound control strategy is presented. Within this control strategy, the proportional-differential (PD) feedback controller is employed to realize the trajectory tracking of end-effector, while the strain and strain rate feedback (SSRF) controller is developed to restrain the vibration of the flexible links using PZT. Furthermore, the stability of the control algorithm is demonstrated based on the Lyapunov stability theory. Finally, two simulation case studies are performed to illustrate the effectiveness of the proposed approach. The results indicate that, under the redundant actuation mode, the hierarchical compound control strategy can guarantee the flexible PM achieves singularity-free motion and vibration attenuation within task workspace simultaneously. The systematic methodology proposed in this study can be conveniently extended for the dynamic modeling and efficient controller design of other flexible PMs, especially the emerging ones with multiple actuation modes.

Protein kinase A is involved in the control of morphology and branching during aerobic growth of Mucor circinelloides

DEFF Research Database (Denmark)

Lübbehüsen, Tina Louise; Polo, V.G.; Rossi, S.

2004-01-01

and colony morphology suggested a role for PKAR in the control of morphology and branching. Here strain KFA121, which overexpresses the M. circinelloides pkaR gene, was used to quantify growth and branching under different aerobic growth conditions in a flow-through cell by computerized image analysis....... An inverse relationship between the pkaR expression level in KFA121 and the hyphal growth unit length was observed in KFA121, suggesting a central role for PKAR in branching. A biochemical analysis of PKAR using antibodies and enzyme assay demonstrated that the level of PKAR is higher in KFA121 under...... indicate that cAMP-dependent PKA in M. circinelloides might be down-regulated during hyphal-tube emergence and that an increase in PKAR levels results in increased branching....

Nonlinear Economic Model Predictive Control Strategy for Active Smart Buildings

DEFF Research Database (Denmark)

Santos, Rui Mirra; Zong, Yi; Sousa, Joao M. C.

2016-01-01

Nowadays, the development of advanced and innovative intelligent control techniques for energy management in buildings is a key issue within the smart grid topic. A nonlinear economic model predictive control (EMPC) scheme, based on the branch-and-bound tree search used as optimization algorithm ...... controller is shown very reliable keeping the comfort levels in the two considered seasons and shifting the load away from peak hours in order to achieve the desired flexible electricity consumption.......Nowadays, the development of advanced and innovative intelligent control techniques for energy management in buildings is a key issue within the smart grid topic. A nonlinear economic model predictive control (EMPC) scheme, based on the branch-and-bound tree search used as optimization algorithm...

Controlling X-ray beam trajectory with a flexible hollow glass fibre

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Yoshihito, E-mail: yotanaka@riken.jp [RIKEN, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan); Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337 (Japan); Nakatani, Takashi; Onitsuka, Rena [Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337 (Japan); Sawada, Kei [RIKEN, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan); Takahashi, Isao [Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337 (Japan)

2014-01-01

X-ray beam trajectory control has been performed by using a 1.5 m-long flexible hollow glass fibre. A two-dimensional scan of a synchrotron radiation beam was demonstrated for X-ray absorption mapping. A metre-length flexible hollow glass fibre with 20 µm-bore and 1.5 mm-cladding diameters for transporting a synchrotron X-ray beam and controlling the trajectory has been examined. The large cladding diameter maintains a moderate curvature to satisfy the shallow glancing angle of total reflection. The observed transmission efficiency was more than 20% at 12.4 keV. As a demonstration, a wide-area scan of a synchrotron radiation beam was performed to identify the elements for a fixed metal film through its absorption spectra.

Controlling the unstable emission of a semiconductor laser subject to conventional optical feedback with a filtered feedback branch.

Science.gov (United States)

Ermakov, I V; Tronciu, V Z; Colet, Pere; Mirasso, Claudio R

2009-05-25

We show the advantages of controlling the unstable dynamics of a semiconductor laser subject to conventional optical feedback by means of a second filtered feedback branch. We give an overview of the analytical solutions of the double cavity feedback and show numerically that the region of stabilization is much larger when using a second branch with filtered feedback than when using a conventional feedback one.

Controlling the unstable emission of a semiconductor laser subject to conventional optical feedback with a filtered feedback branch

OpenAIRE

Ermakov, Ilya; Tronciu, Vasile; Colet, Pere; Mirasso, Claudio R.

2009-01-01

We show the advantages of controlling the unstable dynamics of a semiconductor laser subject to conventional optical feedback by means of a second filtered feedback branch. We give an overview of the analytical solutions of the double cavity feedback and show numerically that the region of stabilization is much larger when using a second branch with filtered feedback than when using a conventional feedback one.

Adaptive control for evaluation of flexibility benefits in microgrid systems

International Nuclear Information System (INIS)

Holjevac, Ninoslav; Capuder, Tomislav; Kuzle, Igor

2015-01-01

Aggregating groups of loads and generators at the same location with centralized control is known as the concept of microgrids. However, if those flexible producers and consumers do not have the ability to balance the variability and uncertainty of RES (renewable energy sources) production within them, from the system perspective they are seen as a source of imbalances and potential problems in maintaining the equilibrium of production and consumption. The papers main goal is to quantify the ability of microgrid components to provide flexibility. This flexibility is analysed from two perspectives, defining two operating principles of each microgrid: independently from the distribution grid and connected, interacting and responding to signals from the upstream system. Following on this, the paper presents two relevant cases. In the first part a deterministic model is developed based on MILP (Mixed Integer Linear programming) simulating the microgrid operation over one year period. This model is used to determine the optimal microgrid configuration with respect to the amount of unused energy, thus defining role and capability of different pieces of equipment and their size (RES (renewable energy sources) wind and solar, HS (heat storage), μCHP (micro combined heat and power plants) and EHP (electric heat pumps)). The second part of this paper further expands the model with MPC (Model Predictive Control) approach in order to capture the behaviour of microgrid interaction with the distribution grid, modelling uncertainties of forecasting RES production by stochastic programming. The model is capable to evaluate both the impact of variable energy production and consumption and the impact of energy balancing tariffs depending on the amount of balancing energy needed for the microgrid operation. - Highlights: • Integrated MILP (Mixed Integer Linear programming) formulation for optimal operation of developed microgrid model. • Determining operational flexibility of

Simultaneous control and piezoelectric insert optimization for manipulators with flexible link

OpenAIRE

Bottega, Valdecir; Pergher, Rejane; Fonseca, Jun S. O.

2009-01-01

This work proposes a tracking control model for a flexible link robotic manipulator using simultaneously motor torques and piezoelectric actuators. The dynamic model of manipulator is obtained in a closed form through the Lagrangian approach. The control uses the motor torques for the tracking control of the joints and also to reduce the low frequency vibration induced in the manipulator links. The stability of this control is guaranteed by the Lyapunov stability theory. Piezoelectric actuato...

A Comparison of the Views of Internal Controllers/Auditors and Branch/Call Center Personnel of the Banks for Operational Risk: A Case for Turkish Banking Sector

Directory of Open Access Journals (Sweden)

Sinemis Zengin

2016-10-01

Full Text Available The aim of this paper is to compare the views of internal controllers/auditors and branch/call center personnel of the banks with respect to the operational risk. Within this scope, we made two different surveys to the personnel in Turkish banks in order to achieve this objective. The first survey was conducted by 310 branch and call center personnel whereas 151 personnel in internal control and audit departments of the banks carried out the second survey. The major finding in this study is that there is a difference in the views of these two groups regarding the evaluation of operational risk. In general, internal controllers/auditors look at the operational risk more negatively than branch/call center personnel. The personnel who control and audit operations in the bank think that operational risk knowledge level of branch/call center personnel is less sufficient, operational risk levels are higher, the controls to avoid this risk are less efficient than branch/call center personnel consider.

Dynamic Beam Solutions for Real-Time Simulation and Control Development of Flexible Rockets

Science.gov (United States)

Su, Weihua; King, Cecilia K.; Clark, Scott R.; Griffin, Edwin D.; Suhey, Jeffrey D.; Wolf, Michael G.

2016-01-01

In this study, flexible rockets are structurally represented by linear beams. Both direct and indirect solutions of beam dynamic equations are sought to facilitate real-time simulation and control development for flexible rockets. The direct solution is completed by numerically integrate the beam structural dynamic equation using an explicit Newmark-based scheme, which allows for stable and fast transient solutions to the dynamics of flexile rockets. Furthermore, in the real-time operation, the bending strain of the beam is measured by fiber optical sensors (FOS) at intermittent locations along the span, while both angular velocity and translational acceleration are measured at a single point by the inertial measurement unit (IMU). Another study in this paper is to find the analytical and numerical solutions of the beam dynamics based on the limited measurement data to facilitate the real-time control development. Numerical studies demonstrate the accuracy of these real-time solutions to the beam dynamics. Such analytical and numerical solutions, when integrated with data processing and control algorithms and mechanisms, have the potential to increase launch availability by processing flight data into the flexible launch vehicle's control system.

Active control of flexible structures using a fuzzy logic algorithm

Science.gov (United States)

Cohen, Kelly; Weller, Tanchum; Ben-Asher, Joseph Z.

2002-08-01

This study deals with the development and application of an active control law for the vibration suppression of beam-like flexible structures experiencing transient disturbances. Collocated pairs of sensors/actuators provide active control of the structure. A design methodology for the closed-loop control algorithm based on fuzzy logic is proposed. First, the behavior of the open-loop system is observed. Then, the number and locations of collocated actuator/sensor pairs are selected. The proposed control law, which is based on the principles of passivity, commands the actuator to emulate the behavior of a dynamic vibration absorber. The absorber is tuned to a targeted frequency, whereas the damping coefficient of the dashpot is varied in a closed loop using a fuzzy logic based algorithm. This approach not only ensures inherent stability associated with passive absorbers, but also circumvents the phenomenon of modal spillover. The developed controller is applied to the AFWAL/FIB 10 bar truss. Simulated results using MATLAB© show that the closed-loop system exhibits fairly quick settling times and desirable performance, as well as robustness characteristics. To demonstrate the robustness of the control system to changes in the temporal dynamics of the flexible structure, the transient response to a considerably perturbed plant is simulated. The modal frequencies of the 10 bar truss were raised as well as lowered substantially, thereby significantly perturbing the natural frequencies of vibration. For these cases, too, the developed control law provides adequate settling times and rates of vibrational energy dissipation.

Singular formalism and admissible control of spacecraft with rotating flexible solar array

Directory of Open Access Journals (Sweden)

Lu Dongning

2014-02-01

Full Text Available This paper is concerned with the attitude control of a three-axis-stabilized spacecraft which consists of a central rigid body and a flexible sun-tracking solar array driven by a solar array drive assembly. Based on the linearization of the dynamics of the spacecraft and the modal identities about the flexible and rigid coupling matrices, the spacecraft attitude dynamics is reduced to a formally singular system with periodically varying parameters, which is quite different from a spacecraft with fixed appendages. In the framework of the singular control theory, the regularity and impulse-freeness of the singular system is analyzed and then admissible attitude controllers are designed by Lyapunov’s method. To improve the robustness against system uncertainties, an H∞ optimal control is designed by optimizing the H∞ norm of the system transfer function matrix. Comparative numerical experiments are performed to verify the theoretical results.

NASA Marshall Space Flight Center Controls Systems Design and Analysis Branch

Science.gov (United States)

Gilligan, Eric

2014-01-01

Marshall Space Flight Center maintains a critical national capability in the analysis of launch vehicle flight dynamics and flight certification of GN&C algorithms. MSFC analysts are domain experts in the areas of flexible-body dynamics and control-structure interaction, thrust vector control, sloshing propellant dynamics, and advanced statistical methods. Marshall's modeling and simulation expertise has supported manned spaceflight for over 50 years. Marshall's unparalleled capability in launch vehicle guidance, navigation, and control technology stems from its rich heritage in developing, integrating, and testing launch vehicle GN&C systems dating to the early Mercury-Redstone and Saturn vehicles. The Marshall team is continuously developing novel methods for design, including advanced techniques for large-scale optimization and analysis.

Activities of the Development Branch. 1978-1981

International Nuclear Information System (INIS)

Candame de Gallo, Rita; Marrapodi, M.R.E.; Baez, L.B.

1982-01-01

The activities carried out by the Development Branch from 1978 through 1981 are summarized. Subjects covered include: Metallurgy, Nuclear Fuels, Instrumentation and Control, Nuclear Reactors, as well as the various projects developed during this period and the administrative and technical activities of various groups belonging to this Branch. A list of publications by personnel of this Branch during the same period is also included. (C.A.K.) [es

A Flexible and Configurable Architecture for Automatic Control Remote Laboratories

Science.gov (United States)

Kalúz, Martin; García-Zubía, Javier; Fikar, Miroslav; Cirka, Luboš

2015-01-01

In this paper, we propose a novel approach in hardware and software architecture design for implementation of remote laboratories for automatic control. In our contribution, we show the solution with flexible connectivity at back-end, providing features of multipurpose usage with different types of experimental devices, and fully configurable…

Controlling flexible rotor vibrations using parametric excitation

Energy Technology Data Exchange (ETDEWEB)

Atepor, L, E-mail: katepor@yahoo.co [Department of Mechanical Engineering, University of Glasgow, G12 8QQ (United Kingdom)

2009-08-01

This paper presents both theoretical and experimental studies of an active vibration controller for vibration in a flexible rotor system. The paper shows that the vibration amplitude can be modified by introducing an axial parametric excitation. The perturbation method of multiple scales is used to solve the equations of motion. The steady-state responses, with and without the parametric excitation terms, is investigated. An experimental test machine uses a piezoelectric exciter mounted on the end of the shaft. The results show a reduction in the rotor response amplitude under principal parametric resonance, and some good correlation between theory and experiment.

Dynamics and Control of a Flexible Solar Sail

Directory of Open Access Journals (Sweden)

Jiafu Liu

2014-01-01

Full Text Available Solar sail can merely make use of solar radiation pressure (SRP force as the thrust for space missions. The attitude dynamics is obtained for the highly flexible solar sail with control vanes, sliding masses, and a gimbaled control boom. The vibration equations are derived considering the geometric nonlinearity of the sail structure subjected to the forces generated by the control vanes, solar radiation pressure (SRP, and sliding masses. Then the dynamic models for attitude/vibration controller design and dynamic simulation are obtained, respectively. The linear quadratic regulator (LQR based and optimal proportional-integral (PI based controllers are designed for the coupled attitude/vibration models with constant disturbance torques caused by the center-of-mass (cm/center-of-pressure (cp offset, respectively. It can be concluded from the theoretical analysis and simulation results that the optimal PI based controller performs better than the LQR based controller from the view of eliminating the steady-state errors. The responses with and without the geometrical nonlinearity are performed, and the differences are observed and analyzed. And some suggestions are also presented.

Improving general flexibility with a mind-body approach: a randomized, controlled trial using neuro emotional Technique®.

Science.gov (United States)

Jensen, Anne M; Ramasamy, Adaikalavan; Hall, Michael W

2012-08-01

General flexibility is a key component of health, well-being, and general physical conditioning. Reduced flexibility has both physical and mental/emotional etiologies and can lead to musculoskeletal injuries and athletic underperformance. Few studies have tested the effectiveness of a mind-body therapy on general flexibility. The aim of this study was to investigate if Neuro Emotional Technique® (NET), a mind-body technique shown to be effective in reducing stress, can also improve general flexibility. The sit-and-reach test (SR) score was used as a measure of general flexibility. Forty-five healthy participants were recruited from the general population and assessed for their initial SR score before being randomly allocated to receive (a) two 20-minute sessions of NET (experimental group); (b) two 20-minute sessions of stretching instruction (active control group); or (c) no intervention or instruction (passive control group). After intervention, the participants were reassessed in a similar manner by the same blind assessor. The participants also answered questions about demographics, usual water and caffeine consumption, and activity level, and they completed an anxiety/mood psychometric preintervention and postintervention. The mean (SD) change in the SR score was +3.1 cm (2.5) in the NET group, +1.2 cm (2.3) in the active control group and +1.0 cm (2.6) in the passive control group. Although all the 3 groups showed some improvement, the improvement in the NET group was statistically significant when compared with that of either the passive controls (p = 0.015) or the active controls (p = 0.021). This study suggests that NET could provide an effective treatment in improving general flexibility. A larger study is required to confirm these findings and also to assess longer term effectiveness of this therapy on general flexibility.

A flexible architecture for advanced process control solutions

Science.gov (United States)

Faron, Kamyar; Iourovitski, Ilia

2005-05-01

Advanced Process Control (APC) is now mainstream practice in the semiconductor manufacturing industry. Over the past decade and a half APC has evolved from a "good idea", and "wouldn"t it be great" concept to mandatory manufacturing practice. APC developments have primarily dealt with two major thrusts, algorithms and infrastructure, and often the line between them has been blurred. The algorithms have evolved from very simple single variable solutions to sophisticated and cutting edge adaptive multivariable (input and output) solutions. Spending patterns in recent times have demanded that the economics of a comprehensive APC infrastructure be completely justified for any and all cost conscious manufacturers. There are studies suggesting integration costs as high as 60% of the total APC solution costs. Such cost prohibitive figures clearly diminish the return on APC investments. This has limited the acceptance and development of pure APC infrastructure solutions for many fabs. Modern APC solution architectures must satisfy the wide array of requirements from very manual R&D environments to very advanced and automated "lights out" manufacturing facilities. A majority of commercially available control solutions and most in house developed solutions lack important attributes of scalability, flexibility, and adaptability and hence require significant resources for integration, deployment, and maintenance. Many APC improvement efforts have been abandoned and delayed due to legacy systems and inadequate architectural design. Recent advancements (Service Oriented Architectures) in the software industry have delivered ideal technologies for delivering scalable, flexible, and reliable solutions that can seamlessly integrate into any fabs" existing system and business practices. In this publication we shall evaluate the various attributes of the architectures required by fabs and illustrate the benefits of a Service Oriented Architecture to satisfy these requirements. Blue

A user's guide to the Flexible Spacecraft Dynamics and Control Program

Science.gov (United States)

Fedor, J. V.

1984-01-01

A guide to the use of the Flexible Spacecraft Dynamics Program (FSD) is presented covering input requirements, control words, orbit generation, spacecraft description and simulation options, and output definition. The program can be used in dynamics and control analysis as well as in orbit support of deployment and control of spacecraft. The program is applicable to inertially oriented spinning, Earth oriented or gravity gradient stabilized spacecraft. Internal and external environmental effects can be simulated.

Quantifying demand flexibility of power-to-heat and thermal energy storage in the control of building heating systems

DEFF Research Database (Denmark)

Finck, Christian; Li, Rongling; Kramer, Rick

2018-01-01

restricted by power-to-heat conversion such as heat pumps and thermal energy storage possibilities of a building. To quantify building demand flexibility, it is essential to capture the dynamic response of the building energy system with thermal energy storage. To identify the maximum flexibility a building......’s energy system can provide, optimal control is required. In this paper, optimal control serves to determine in detail demand flexibility of an office building equipped with heat pump, electric heater, and thermal energy storage tanks. The demand flexibility is quantified using different performance...... of TES and power-to-heat in any case of charging, discharging or idle mode. A simulation case study is performed showing that a water tank, a phase change material tank, and a thermochemical material tank integrated with building heating system can be designed to provide flexibility with optimal control....

Branching structure and strain hardening of branched metallocene polyethylenes

International Nuclear Information System (INIS)

Torres, Enrique; Li, Si-Wan; Costeux, Stéphane; Dealy, John M.

2015-01-01

There have been a number of studies of a series of branched metallocene polyethylenes (BMPs) made in a solution, continuous stirred tank reactor (CSTR) polymerization. The materials studied vary in branching level in a systematic way, and the most highly branched members of the series exhibit mild strain hardening. An outstanding question is which types of branched molecules are responsible for strain hardening in extension. This question is explored here by use of polymerization and rheological models along with new data on the extensional flow behavior of the most highly branched members of the set. After reviewing all that is known about the effects of various branching structures in homogeneous polymers and comparing this with the structures predicted to be present in BMPs, it is concluded that in spite of their very low concentration, treelike molecules with branch-on-branch structure provide a large number of deeply buried inner segments that are essential for strain hardening in these polymers

Branching structure and strain hardening of branched metallocene polyethylenes

Energy Technology Data Exchange (ETDEWEB)

Torres, Enrique; Li, Si-Wan; Costeux, Stéphane; Dealy, John M., E-mail: john.dealy@mcgill.ca [Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 0C4 (Canada)

2015-09-15

There have been a number of studies of a series of branched metallocene polyethylenes (BMPs) made in a solution, continuous stirred tank reactor (CSTR) polymerization. The materials studied vary in branching level in a systematic way, and the most highly branched members of the series exhibit mild strain hardening. An outstanding question is which types of branched molecules are responsible for strain hardening in extension. This question is explored here by use of polymerization and rheological models along with new data on the extensional flow behavior of the most highly branched members of the set. After reviewing all that is known about the effects of various branching structures in homogeneous polymers and comparing this with the structures predicted to be present in BMPs, it is concluded that in spite of their very low concentration, treelike molecules with branch-on-branch structure provide a large number of deeply buried inner segments that are essential for strain hardening in these polymers.

Phase and gain control policies for robust active vibration control of flexible structures

International Nuclear Information System (INIS)

Zhang, K; Ichchou, M N; Scorletti, G; Mieyeville, F

2013-01-01

The interest of this paper is to develop a general and systematic robust control methodology for active vibration control of flexible structures. For this purpose, first phase and gain control policies are proposed to impose qualitative frequency-dependent requirements on the controller to consider a complete set of control objectives. Then the proposed control methodology is developed by employing phase and gain control policies in the dynamic output feedback H ∞  control: according to the set of control objectives, phase and gain control policies incorporate necessary weighting functions and determine them in a rational and systematic way; on the other hand, with the appropriate weighting functions efficient H ∞  control algorithms can automatically realize phase and gain control policies and generate a satisfactory H ∞  controller. The proposed control methodology can be used for both SISO and MIMO systems with collocated or non-collocated sensors and actuators. In this paper, it is validated on a non-collocated piezoelectric cantilever beam. Both numerical simulations and experimental results demonstrate the effectiveness of the proposed control methodology. (paper)

An investigation of cognitive 'branching' processes in major depression

Directory of Open Access Journals (Sweden)

Williams Steven CR

2009-11-01

Full Text Available Abstract Background Patients with depression demonstrate cognitive impairment on a wide range of cognitive tasks, particularly putative tasks of frontal lobe function. Recent models of frontal lobe function have argued that the frontal pole region is involved in cognitive branching, a process requiring holding in mind one goal while performing sub-goal processes. Evidence for this model comes from functional neuroimaging and frontal-pole lesion patients. We have utilised these new concepts to investigate the possibility that patients with depression are impaired at cognitive 'branching'. Methods 11 non-medicated patients with major depression were compared to 11 matched controls in a behavioural study on a task of cognitive 'branching'. In the version employed here, we recorded participant's performance as they learnt to perform the task. This involved participants completing a control condition, followed by a working memory condition, a dual-task condition and finally the branching condition, which integrates processes in the working memory and dual-task conditions. We also measured participants on a number of other cognitive tasks as well as mood-state before and after the branching experiment. Results Patients took longer to learn the first condition, but performed comparably to controls after six runs of the task. Overall, reaction times decreased with repeated exposure on the task conditions in controls, with this effect attenuated in patients. Importantly, no differences were found between patients and controls on the branching condition. There was, however, a significant change in mood-state with patients increasing in positive affect and decreasing in negative affect after the experiment. Conclusion We found no clear evidence of a fundamental impairment in anterior prefrontal 'branching processes' in patients with depression. Rather our data argue for a contextual learning impairment underlying cognitive dysfunction in this disorder. Our

An investigation of cognitive 'branching' processes in major depression.

Science.gov (United States)

Walsh, Nicholas D; Seal, Marc L; Williams, Steven C R; Mehta, Mitul A

2009-11-10

Patients with depression demonstrate cognitive impairment on a wide range of cognitive tasks, particularly putative tasks of frontal lobe function. Recent models of frontal lobe function have argued that the frontal pole region is involved in cognitive branching, a process requiring holding in mind one goal while performing sub-goal processes. Evidence for this model comes from functional neuroimaging and frontal-pole lesion patients. We have utilised these new concepts to investigate the possibility that patients with depression are impaired at cognitive 'branching'. 11 non-medicated patients with major depression were compared to 11 matched controls in a behavioural study on a task of cognitive 'branching'. In the version employed here, we recorded participant's performance as they learnt to perform the task. This involved participants completing a control condition, followed by a working memory condition, a dual-task condition and finally the branching condition, which integrates processes in the working memory and dual-task conditions. We also measured participants on a number of other cognitive tasks as well as mood-state before and after the branching experiment. Patients took longer to learn the first condition, but performed comparably to controls after six runs of the task. Overall, reaction times decreased with repeated exposure on the task conditions in controls, with this effect attenuated in patients. Importantly, no differences were found between patients and controls on the branching condition. There was, however, a significant change in mood-state with patients increasing in positive affect and decreasing in negative affect after the experiment. We found no clear evidence of a fundamental impairment in anterior prefrontal 'branching processes' in patients with depression. Rather our data argue for a contextual learning impairment underlying cognitive dysfunction in this disorder. Our data suggest that MDD patients are able to perform high

Dynamic modelling and adaptive robust tracking control of a space robot with two-link flexible manipulators under unknown disturbances

Science.gov (United States)

Yang, Xinxin; Ge, Shuzhi Sam; He, Wei

2018-04-01

In this paper, both the closed-form dynamics and adaptive robust tracking control of a space robot with two-link flexible manipulators under unknown disturbances are developed. The dynamic model of the system is described with assumed modes approach and Lagrangian method. The flexible manipulators are represented as Euler-Bernoulli beams. Based on singular perturbation technique, the displacements/joint angles and flexible modes are modelled as slow and fast variables, respectively. A sliding mode control is designed for trajectories tracking of the slow subsystem under unknown but bounded disturbances, and an adaptive sliding mode control is derived for slow subsystem under unknown slowly time-varying disturbances. An optimal linear quadratic regulator method is proposed for the fast subsystem to damp out the vibrations of the flexible manipulators. Theoretical analysis validates the stability of the proposed composite controller. Numerical simulation results demonstrate the performance of the closed-loop flexible space robot system.

On the concept of flexibility: A dual control perspective

NARCIS (Netherlands)

A.C.J. de Leeuw (A. C J); H.W. Volberda (Henk)

1996-01-01

textabstractOrganizational flexibility has recently received much attention from researchers, management consultants and practitioners. In general, the term 'flexibility' has a positive connotation: flexible organizations are the better ones. However, the meaning of flexibility as well as its

Stability control of a flexible maneuverable tethered space net robot

Science.gov (United States)

Zhang, Fan; Huang, Panfeng

2018-04-01

As a promising solution for active space debris capture and removal, a maneuverable Tethered Space Net Robot (TSNR) is proposed as an improved Space Tethered Net (TSN). In addition to the advantages inherit to the TSN, the TSNR's maneuverability expands the capture's potential. However, oscillations caused by the TSNR's flexibility and elasticity of make higher requests of the control scheme. Based on the dynamics model, a modified adaptive super-twisting sliding mode control scheme is proposed in this paper for TSNR stability control. The proposed continuous control force can effectively suppress oscillations. Theoretical verification and numerical simulations demonstrate that the desired trajectory can be tracked steadily and efficiently by employing the proposed control scheme.

On the concept of flexibility : A dual control perspective

NARCIS (Netherlands)

de Leeuw, A.C.J.; Volberda, H.W.

Organizational flexibility has recently received much attention from researchers, management consultants and practitioners, In general, the term 'flexibility' has a positive connotation: flexible organizations are the better ones. However, the meaning of flexibility as well as its relation to the

Optimal Sliding Mode Controllers for Attitude Stabilization of Flexible Spacecraft

Directory of Open Access Journals (Sweden)

Chutiphon Pukdeboon

2011-01-01

Full Text Available The robust optimal attitude control problem for a flexible spacecraft is considered. Two optimal sliding mode control laws that ensure the exponential convergence of the attitude control system are developed. Integral sliding mode control (ISMC is applied to combine the first-order sliding mode with optimal control and is used to control quaternion-based spacecraft attitude manoeuvres with external disturbances and an uncertainty inertia matrix. For the optimal control part the state-dependent Riccati equation (SDRE and optimal Lyapunov techniques are employed to solve the infinite-time nonlinear optimal control problem. The second method of Lyapunov is used to guarantee the stability of the attitude control system under the action of the proposed control laws. An example of multiaxial attitude manoeuvres is presented and simulation results are included to verify the usefulness of the developed controllers.

Soft control of scanning probe microscope with high flexibility.

Science.gov (United States)

Liu, Zhenghui; Guo, Yuzheng; Zhang, Zhaohui; Zhu, Xing

2007-01-01

Most commercial scanning probe microscopes have multiple embedded digital microprocessors and utilize complex software for system control, which is not easily obtained or modified by researchers wishing to perform novel and special applications. In this paper, we present a simple and flexible control solution that just depends on software running on a single-processor personal computer with real-time Linux operating system to carry out all the control tasks including negative feedback, tip moving, data processing and user interface. In this way, we fully exploit the potential of a personal computer in calculating and programming, enabling us to manipulate the scanning probe as required without any special digital control circuits and related technical know-how. This solution has been successfully applied to a homemade ultrahigh vacuum scanning tunneling microscope and a multiprobe scanning tunneling microscope.

On the concept of flexibility: A dual control perspective

OpenAIRE

Leeuw, A. C J; Volberda, Henk

1996-01-01

textabstractOrganizational flexibility has recently received much attention from researchers, management consultants and practitioners. In general, the term 'flexibility' has a positive connotation: flexible organizations are the better ones. However, the meaning of flexibility as well as its relation to the functioning of an organization is still ambiguous. This article develops a systematic and multidimensional picture of flexibility on the basis of views taken from the systems theory of co...

Energy Flexibility in Retail Buildings

DEFF Research Database (Denmark)

Ma, Zheng; Billanes, Joy Dalmacio; Kjærgaard, Mikkel Baun

2017-01-01

Retail buildings has an important role for demand side energy flexibility because of their high energy consumption, variety of energy flexibility resources, and centralized control via building control systems. Energy flexibility requires agreements and collaborations among different actors......), with the discussion of the stakeholders’ roles and their interrelation in delivering energy flexibility with the influential factors to the actual implementation of energy flexible operation of their buildings. Based on a literature analysis, the results cover stakeholders’ types and roles, perceptions (drivers......, barriers, and benefits), energy management activities and technology adoptions, and the stakeholders’ interaction for the energy flexibility in retail buildings....

Cravity modulation of the moss Tortula modica branching

Science.gov (United States)

Khorkavtsiv, Yaroslava; Kit, Nadja

Among various abiotic factors the sensor system of plants constantly perceives light and gravitation impulses and reacts on their action by photo- and gravitropisms. Tropisms play fundamental part in ontogenesis and determination of plant forms. Essentially important question is how light initiating phototropic bending modulates gravitropism. In contrast to flower plants, red light is phototropically active for mosses, and phytochromic system controls initiation of apical growth, branching and photomorphogenesis of mosses. The aim of this investigation was to analyse cell branching of protonemata Tortula modica Zander depending on the direction of light and gravitation vector. The influence of light and gravitation on the form of protonemal turf T. modica, branching and the angle of lateral branches relative to axis of mother cell growth has been investigated. As moss protonemata is not branched in the darkness, light is necessary for branching activation. Minimally low intensity of the red light (0.2 mmol (.) m (-2) ({) .}sec (-1) ) induced branching without visual display of phototropic growth. It has been established that unidirectional action of light and gravitation intensifies branching, and, on the contrary, perpendicularly oriented vectors of factors weaken branches formation. Besides, parallel oriented vectors initiated branching from both cell sides, but oppositely directed vectors initiated branching only from one side. Clinostate rotation the change of the vector gravity and causes uniform cell branching, hence, light and gravitation mutually influence the branching system form of the protonemata cell. It has been shown that the angle of lateral branches in darkness does not depend on the direction of light and gravitation action. After lighting the local growth of the cell wall took place mainly under the angle 90 (o) to the axes of mother cell growth. Then the angle gradually decreased and in 3-4 cell divisions the lateral branch grew under the angle

Demonstration of non-collocated vibration control of a flexible manipulator using electrical dynamic absorbers

International Nuclear Information System (INIS)

Kim, Sang-Myeong; Kim, Heungseob; Boo, Kwangsuck; Brennan, Michael J

2013-01-01

This paper describes an experimental study into the vibration control of a servo system comprising a servo motor and a flexible manipulator. Two modes of the system are controlled by using the servo motor and an accelerometer attached to the tip of the flexible manipulator. The control system is thus non-collocated. It consists of two electrical dynamic absorbers, each of which consists of a modal filter and, in case of an out-of-phase mode, a phase inverter. The experimental results show that each absorber acts as a mechanical dynamic vibration absorber attached to each mode and significantly reduces the settling time for the system response to a step input. (technical note)

Fabrication and performance evaluation of flexible heat pipes for potential thermal control of foldable electronics

International Nuclear Information System (INIS)

Yang, Chao; Chang, Chao; Song, Chengyi; Shang, Wen; Wu, Jianbo; Tao, Peng; Deng, Tao

2016-01-01

Highlights: • A flexible and high-performance heat pipe is fabricated. • Bending effect on thermal performance of flexible heat pipes is evaluated. • Theoretical analysis is carried out to reveal the change of thermal resistance with bending. • Thermal control of foldable electronics with flexible heat pipes is demonstrated. - Abstract: In this work, we report the fabrication and thermal performance evaluation of flexible heat pipes prepared by using a fluororubber tube as the connector in the adiabatic section and using strong base treated hydrophilic copper meshes as the wick structure. Deionized water was chosen as working fluid and three different filling ratios (10%, 20%, and 30%) of working fluid were loaded into the heat pipe to investigate its impact on thermal performance. The fabricated heat pipes can be easily bended from 0"o to 180"o in the horizontal operation mode and demonstrated consistently low thermal resistances after repeated bending. It was found that with optimized amount of working fluid, the thermal resistance of flexible heat pipes increased with larger bending angles. Theoretical analysis reveals that bending disturbs the normal vapor flow from evaporator to condenser in the heat pipe, thus leads to increased liquid–vapor interfacial thermal resistance in the evaporator section. The flexible heat pipes have been successfully applied for thermal control of foldable electronic devices showing superior uniform heat-transfer performance.

Association mapping in sunflower (Helianthus annuus L.) reveals independent control of apical vs. basal branching.

Science.gov (United States)

Nambeesan, Savithri U; Mandel, Jennifer R; Bowers, John E; Marek, Laura F; Ebert, Daniel; Corbi, Jonathan; Rieseberg, Loren H; Knapp, Steven J; Burke, John M

2015-03-11

Shoot branching is an important determinant of plant architecture and influences various aspects of growth and development. Selection on branching has also played an important role in the domestication of crop plants, including sunflower (Helianthus annuus L.). Here, we describe an investigation of the genetic basis of variation in branching in sunflower via association mapping in a diverse collection of cultivated sunflower lines. Detailed phenotypic analyses revealed extensive variation in the extent and type of branching within the focal population. After correcting for population structure and kinship, association analyses were performed using a genome-wide collection of SNPs to identify genomic regions that influence a variety of branching-related traits. This work resulted in the identification of multiple previously unidentified genomic regions that contribute to variation in branching. Genomic regions that were associated with apical and mid-apical branching were generally distinct from those associated with basal and mid-basal branching. Homologs of known branching genes from other study systems (i.e., Arabidopsis, rice, pea, and petunia) were also identified from the draft assembly of the sunflower genome and their map positions were compared to those of associations identified herein. Numerous candidate branching genes were found to map in close proximity to significant branching associations. In sunflower, variation in branching is genetically complex and overall branching patterns (i.e., apical vs. basal) were found to be influenced by distinct genomic regions. Moreover, numerous candidate branching genes mapped in close proximity to significant branching associations. Although the sunflower genome exhibits localized islands of elevated linkage disequilibrium (LD), these non-random associations are known to decay rapidly elsewhere. The subset of candidate genes that co-localized with significant associations in regions of low LD represents the most

A multi-mode operation control strategy for flexible microgrid based on sliding-mode direct voltage and hierarchical controls.

Science.gov (United States)

Zhang, Qinjin; Liu, Yancheng; Zhao, Youtao; Wang, Ning

2016-03-01

Multi-mode operation and transient stability are two problems that significantly affect flexible microgrid (MG). This paper proposes a multi-mode operation control strategy for flexible MG based on a three-layer hierarchical structure. The proposed structure is composed of autonomous, cooperative, and scheduling controllers. Autonomous controller is utilized to control the performance of the single micro-source inverter. An adaptive sliding-mode direct voltage loop and an improved droop power loop based on virtual negative impedance are presented respectively to enhance the system disturbance-rejection performance and the power sharing accuracy. Cooperative controller, which is composed of secondary voltage/frequency control and phase synchronization control, is designed to eliminate the voltage/frequency deviations produced by the autonomous controller and prepare for grid connection. Scheduling controller manages the power flow between the MG and the grid. The MG with the improved hierarchical control scheme can achieve seamless transitions from islanded to grid-connected mode and have a good transient performance. In addition the presented work can also optimize the power quality issues and improve the load power sharing accuracy between parallel VSIs. Finally, the transient performance and effectiveness of the proposed control scheme are evaluated by theoretical analysis and simulation results. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

LQG/LTR optimal attitude control of small flexible spacecraft using free-free boundary conditions

Science.gov (United States)

Fulton, Joseph M.

Due to the volume and power limitations of a small satellite, careful consideration must be taken while designing an attitude control system for 3-axis stabilization. Placing redundancy in the system proves difficult and utilizing power hungry, high accuracy, active actuators is not a viable option. Thus, it is customary to find dependable, passive actuators used in conjunction with small scale active control components. This document describes the application of Elastic Memory Composite materials in the construction of a flexible spacecraft appendage, such as a gravity gradient boom. Assumed modes methods are used with Finite Element Modeling information to obtain the equations of motion for the system while assuming free-free boundary conditions. A discussion is provided to illustrate how cantilever mode shapes are not always the best assumption when modeling small flexible spacecraft. A key point of interest is first resonant modes may be needed in the system design plant in spite of these modes being greater than one order of magnitude in frequency when compared to the crossover frequency of the controller. LQG/LTR optimal control techniques are implemented to compute attitude control gains while controller robustness considerations determine appropriate reduced order controllers and which flexible modes to include in the design model. Key satellite designer concerns in the areas of computer processor sizing, material uncertainty impacts on the system model, and system performance variations resulting from appendage length modifications are addressed.

Probing the molecular design of hyper-branched aryl polyesters towards lubricant applications.

Science.gov (United States)

Robinson, Joshua W; Zhou, Yan; Bhattacharya, Priyanka; Erck, Robert; Qu, Jun; Bays, J Timothy; Cosimbescu, Lelia

2016-01-05

We report novel polymeric materials that may be used as viscosity index improvers (VII) for lubricant applications. Our efforts included probing the comb-burst hyper-branched aryl polyester architecture for beneficial viscosity and friction behavior when utilized as an additive in a group I oil. The monomer was designed as to undergo polymerization via polycondensation within the architectural construct (AB2), typical of hyperbranched polymers. The monomer design was comprised of aliphatic arms (12 or 16 methylenes) to provide the necessary lipophilicity to achieve solubility in a non-polar medium. Once polymerized, via catalyst and heat, the surface alcohols were functionalized with fatty acids (lauric and palmitic). Controlling the aliphatic nature of the internal arms and peripheral end-groups provided four unique flexible polymer designs. Changing the reaction time and concentration provided opportunities to investigate the influence of molecular weight and branching density on oil-solubility, viscosity, and friction. Oil-solubility was found to decrease with fewer internal carbons, but the number of internal carbons appears to have little influence on the bulk solution viscosity. At concentrations of 2 wt % in a group I base oil, these polymer additives demonstrated an improved viscosity index and reduced friction coefficient, validating the basic approach.

Probing the molecular design of hyper-branched aryl polyesters towards lubricant applications

Science.gov (United States)

Robinson, Joshua W.; Zhou, Yan; Bhattacharya, Priyanka; Erck, Robert; Qu, Jun; Bays, J. Timothy; Cosimbescu, Lelia

2016-01-01

We report novel polymeric materials that may be used as viscosity index improvers (VII) for lubricant applications. Our efforts included probing the comb-burst hyper-branched aryl polyester architecture for beneficial viscosity and friction behavior when utilized as an additive in a group I oil. The monomer was designed as to undergo polymerization via polycondensation within the architectural construct (AB2), typical of hyperbranched polymers. The monomer design was comprised of aliphatic arms (12 or 16 methylenes) to provide the necessary lipophilicity to achieve solubility in a non-polar medium. Once polymerized, via catalyst and heat, the surface alcohols were functionalized with fatty acids (lauric and palmitic). Controlling the aliphatic nature of the internal arms and peripheral end-groups provided four unique flexible polymer designs. Changing the reaction time and concentration provided opportunities to investigate the influence of molecular weight and branching density on oil-solubility, viscosity, and friction. Oil-solubility was found to decrease with fewer internal carbons, but the number of internal carbons appears to have little influence on the bulk solution viscosity. At concentrations of 2 wt % in a group I base oil, these polymer additives demonstrated an improved viscosity index and reduced friction coefficient, validating the basic approach.

41 CFR 102-74.330 - What smoking restrictions apply to outside areas under Executive branch control?

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What smoking restrictions apply to outside areas under Executive branch control? 102-74.330 Section 102-74.330 Public... MANAGEMENT REGULATION REAL PROPERTY 74-FACILITY MANAGEMENT Facility Management Smoking § 102-74.330 What...

Control system design for flexible rotors supported by actively lubricated bearings

DEFF Research Database (Denmark)

Nicoletti, Rodrigo; Santos, Ilmar

2008-01-01

and keeping the lengths of the two eigenvalues constant in the real-imaginary plane. The methodology is applied to an industrial gas compressor supported by active tilting-pad journal bearings. The unbalance response functions and mode shapes of the flexible rotor with and without active control are presented...

Adaptive Jacobian Fuzzy Attitude Control for Flexible Spacecraft Combined Attitude and Sun Tracking System

Science.gov (United States)

Chak, Yew-Chung; Varatharajoo, Renuganth

2016-07-01

Many spacecraft attitude control systems today use reaction wheels to deliver precise torques to achieve three-axis attitude stabilization. However, irrecoverable mechanical failure of reaction wheels could potentially lead to mission interruption or total loss. The electrically-powered Solar Array Drive Assemblies (SADA) are usually installed in the pitch axis which rotate the solar arrays to track the Sun, can produce torques to compensate for the pitch-axis wheel failure. In addition, the attitude control of a flexible spacecraft poses a difficult problem. These difficulties include the strong nonlinear coupled dynamics between the rigid hub and flexible solar arrays, and the imprecisely known system parameters, such as inertia matrix, damping ratios, and flexible mode frequencies. In order to overcome these drawbacks, the adaptive Jacobian tracking fuzzy control is proposed for the combined attitude and sun-tracking control problem of a flexible spacecraft during attitude maneuvers in this work. For the adaptation of kinematic and dynamic uncertainties, the proposed scheme uses an adaptive sliding vector based on estimated attitude velocity via approximate Jacobian matrix. The unknown nonlinearities are approximated by deriving the fuzzy models with a set of linguistic If-Then rules using the idea of sector nonlinearity and local approximation in fuzzy partition spaces. The uncertain parameters of the estimated nonlinearities and the Jacobian matrix are being adjusted online by an adaptive law to realize feedback control. The attitude of the spacecraft can be directly controlled with the Jacobian feedback control when the attitude pointing trajectory is designed with respect to the spacecraft coordinate frame itself. A significant feature of this work is that the proposed adaptive Jacobian tracking scheme will result in not only the convergence of angular position and angular velocity tracking errors, but also the convergence of estimated angular velocity to

Age-dependent branching processes for surveillance of vaccine-preventable diseases with incubation period

Directory of Open Access Journals (Sweden)

Marusia N Bojkova

2010-10-01

Full Text Available The purpose of this paper is to review the recent results of the authors in the area of infectious disease modelling by means of branching stochastic processes. This is a new approach involving age-dependent branching models, which turned out to be more appropriate and flexible for describing the spread of an infection in a given population, than discrete time ones. Concretely, Bellman-Harris and Sevast’yanov’s branching processes are investigated. It is justified that the proposed models are proper candidates as models of infectious diseases with incubation period like measles, mumps, avian flu, etc. It is worth to notice that in general the developed methodology is applicable to the diseases that follow the so-called SIR (susceptible- infected-removed scheme in terms of epidemiological models. Two policies of extra-vaccination level are proposed and compared on the ground of simulation examples.

Controllable synthesis and sintering of silver nanoparticles for inkjet-printed flexible electronics

International Nuclear Information System (INIS)

Zhang, Zhiliang; Zhu, Weiyue

2015-01-01

An effective and facile strategy was developed to successfully synthesize nearly uniform silver nanoparticles (AgNPs) with particle size of <10 nm, and demonstrated to achieve the sintering of AgNPs at room temperature for inkjet-printed flexible electronics. In such system, a series of different chain-length alkylamines were exploited as capped molecules to controllable synthesis of uniform AgNPs with the mean nanoparticle size in rang of 8.6 ± 0.9, 8.9 ± 1.2 and 9.2 ± 1.6 nm, and these ultra-small nanoparticles were very favorable to attain an excellent printing fluency. Based on the as-synthesized AgNPs, a sequence of flexible electrocircuits was successfully fabricated by ink-jet printing technique. After the dipped treatment, the printed AgNPs were achieved to spontaneous coalescence and aggregation at room temperature induced by preferential dissolution of capped molecules on AgNPs surfaces into methanol solution. These aggregated AgNPs demonstrated superior controllability, excellent stability and low resistivity in the range of 31.6–26.5 μΩ cm, and would have enormous potential in the application to be tailored for assembly of optoelectronics devices. - Highlights: • Silver nanoparticles with particle size of <10 nm was controllably synthesized. • The sintering of silver nanoparticles was conducted at room temperature. • The resistivity was reached as low as 26.5 μΩ cm for flexible electronics

Positive affect and cognitive control: approach-motivation intensity influences the balance between cognitive flexibility and stability.

Science.gov (United States)

Liu, Ya; Wang, Zhenhong

2014-05-01

In most prior research, positive affect has been consistently found to promote cognitive flexibility. However, the motivational dimensional model of affect assumes that the influence of positive affect on cognitive processes is modulated by approach-motivation intensity. In the present study, we extended the motivational dimensional model to the domain of cognitive control by examining the effect of low- versus high-approach-motivated positive affect on the balance between cognitive flexibility and stability in an attentional-set-shifting paradigm. Results showed that low-approach-motivated positive affect promoted cognitive flexibility but also caused higher distractibility, whereas high-approach-motivated positive affect enhanced perseverance but simultaneously reduced distractibility. These results suggest that the balance between cognitive flexibility and stability is modulated by the approach-motivation intensity of positive affective states. Therefore, it is essential to incorporate motivational intensity into studies on the influence of affect on cognitive control.

Wing Shaping and Gust Load Controls of Flexible Aircraft: An LPV Approach

Science.gov (United States)

Hammerton, Jared R.; Su, Weihua; Zhu, Guoming; Swei, Sean Shan-Min

2018-01-01

In the proposed paper, the optimum wing shape of a highly flexible aircraft under varying flight conditions will be controlled by a linear parameter-varying approach. The optimum shape determined under multiple objectives, including flight performance, ride quality, and control effort, will be determined as well. This work is an extension of work done previously by the authors, and updates the existing optimization and utilizes the results to generate a robust flight controller.

Comprehensive modeling and control of flexible flapping wing micro air vehicles

Science.gov (United States)

Nogar, Stephen Michael

Flapping wing micro air vehicles hold significant promise due to the potential for improved aerodynamic efficiency, enhanced maneuverability and hover capability compared to fixed and rotary configurations. However, significant technical challenges exist to due the lightweight, highly integrated nature of the vehicle and coupling between the actuators, flexible wings and control system. Experimental and high fidelity analysis has demonstrated that aeroelastic effects can change the effective kinematics of the wing, reducing vehicle stability. However, many control studies for flapping wing vehicles do not consider these effects, and instead validate the control strategy with simple assumptions, including rigid wings, quasi-steady aerodynamics and no consideration of actuator dynamics. A control evaluation model that includes aeroelastic effects and actuator dynamics is developed. The structural model accounts for geometrically nonlinear behavior using an implicit condensation technique and the aerodynamic loads are found using a time accurate approach that includes quasi-steady, rotational, added mass and unsteady effects. Empirically based parameters in the model are fit using data obtained from a higher fidelity solver. The aeroelastic model and its ingredients are compared to experiments and computations using models of higher fidelity, and indicate reasonable agreement. The developed control evaluation model is implemented in a previously published, baseline controller that maintains stability using an asymmetric wingbeat, known as split-cycle, along with changing the flapping frequency and wing bias. The model-based controller determines the control inputs using a cycle-averaged, linear control design model, which assumes a rigid wing and no actuator dynamics. The introduction of unaccounted for dynamics significantly degrades the ability of the controller to track a reference trajectory, and in some cases destabilizes the vehicle. This demonstrates the

Induced chorioretinal venous anastomosis in experimental retinal branch vein occlusion.

OpenAIRE

McAllister, I L; Yu, D Y; Vijayasekaran, S; Barry, C; Constable, I

1992-01-01

Iatrogenic retinal vein to choroidal vein anastomoses were created using laser photocoagulation in six of seven dog eyes in which a partial branch retinal vein occlusion had previously been created photochemically. A similar attempt to create an anastomosis was made in six control eyes in which no branch vein occlusion was present. In the eyes in which a branch retinal vein had been created, a venous chorioretinal anastomosis appeared to be present by 3 to 6 weeks. In three control eyes simil...

Feedback-Controlled Lubrication for Reducing the Lateral Vibration of Flexible Rotors supported by Tilting-Pad Journal Bearings

DEFF Research Database (Denmark)

Salazar, Jorge Andrés González; Santos, Ilmar

2014-01-01

In this work, the feedback-controlled lubrication regime, based on a model-free designed proportional-derivative (PD) controller, is studied and experimentally tested in a flexible rotor mounted on an actively-lubricated tilting-pad journal bearing (active TPJB). With such a lubrication regime...... to experimentally characterized multi-input multi-output systems is used to determine the stabilizing PD gain domain. The main contribution of this work is to demonstrate the enhancement of the dynamic response of a flexible rotor-bearing system supported by an active TPJB by means of the feedback...... are used as actuators and the flexible rotor lateral movements as feedback control signals. To synthesise the PD controller gains an objective function is optimized in the stabilizing gain domain and then chosen from a subdomain imposed by the servovalves restrictions. The D-decomposition approach expanded...

Adaptive Neural Back-Stepping Control with Constrains for a Flexible Air-Breathing Hypersonic Vehicle

Directory of Open Access Journals (Sweden)

Pengfei Wang

2015-01-01

Full Text Available The design of an adaptive neural back-stepping control for a flexible air-breathing hypersonic vehicle (AHV in the presence of input constraint and aerodynamic uncertainty is discussed. Based on functional decomposition, the dynamics can be decomposed into the velocity subsystem and the altitude subsystem. To guarantee the exploited controller’s robustness with respect to parametric uncertainties, neural network (NN is applied to approximate the lumped uncertainty of each subsystem of AHV model. The exceptional contribution is that novel auxiliary systems are introduced to compensate both the tracking errors and desired control laws, based on which the explored controller can still provide effective tracking of velocity and altitude commands when the actuators are saturated. Finally, simulation studies are made to illustrate the effectiveness of the proposed control approach in spite of the flexible effects, system uncertainties, and varying disturbances.

High Performance, Robust Control of Flexible Space Structures: MSFC Center Director's Discretionary Fund

Science.gov (United States)

Whorton, M. S.

1998-01-01

Many spacecraft systems have ambitious objectives that place stringent requirements on control systems. Achievable performance is often limited because of difficulty of obtaining accurate models for flexible space structures. To achieve sufficiently high performance to accomplish mission objectives may require the ability to refine the control design model based on closed-loop test data and tune the controller based on the refined model. A control system design procedure is developed based on mixed H2/H(infinity) optimization to synthesize a set of controllers explicitly trading between nominal performance and robust stability. A homotopy algorithm is presented which generates a trajectory of gains that may be implemented to determine maximum achievable performance for a given model error bound. Examples show that a better balance between robustness and performance is obtained using the mixed H2/H(infinity) design method than either H2 or mu-synthesis control design. A second contribution is a new procedure for closed-loop system identification which refines parameters of a control design model in a canonical realization. Examples demonstrate convergence of the parameter estimation and improved performance realized by using the refined model for controller redesign. These developments result in an effective mechanism for achieving high-performance control of flexible space structures.

Finite Element Analysis for Active-force Control on Vibration of a Flexible Single-link Manipulator

Directory of Open Access Journals (Sweden)

Abdul Kadir Muhammad

2015-10-01

Full Text Available The purposes of this research are to formulate the equations of motion of the system, to develop computational codes by a finite element analysis in order to perform dynamics simulation with vibration control, to propose an effective control scheme using active-force (AF control a flexible single-link manipulator. The system used in this paper consists of an aluminum beam as a flexible link, a clamp-part, a servo motor to rotate the link and a piezoelectric actuator to control vibration. Computational codes on time history responses, FFT (Fast Fourier Transform processing and eigenvalues-eigenvectors analysis were developed to calculate dynamic behavior of the link. Furthermore, the AF control was designed to drive the piezoelectric actuator. Calculated results have revealed that the vibration of the system can be suppressed effectively.

Controlling Flexible Robot Arms Using High Speed Dynamics Process

Science.gov (United States)

Jain, Abhinandan (Inventor)

1996-01-01

A robot manipulator controller for a flexible manipulator arm having plural bodies connected at respective movable hinges and flexible in plural deformation modes corresponding to respective modal spatial influence vectors relating deformations of plural spaced nodes of respective bodies to the plural deformation modes, operates by computing articulated body quantities for each of the bodies from respective modal spatial influence vectors, obtaining specified body forces for each of the bodies, and computing modal deformation accelerations of the nodes and hinge accelerations of the hinges from the specified body forces, from the articulated body quantities and from the modal spatial influence vectors. In one embodiment of the invention, the controller further operates by comparing the accelerations thus computed to desired manipulator motion to determine a motion discrepancy, and correcting the specified body forces so as to reduce the motion discrepancy. The manipulator bodies and hinges are characterized by respective vectors of deformation and hinge configuration variables, and computing modal deformation accelerations and hinge accelerations is carried out for each one of the bodies beginning with the outermost body by computing a residual body force from a residual body force of a previous body and from the vector of deformation and hinge configuration variables, computing a resultant hinge acceleration from the body force, the residual body force and the articulated hinge inertia, and revising the residual body force modal body acceleration.

Finite Element Analysis for Active-force Control on Vibration of a Flexible Single-link Manipulator

Directory of Open Access Journals (Sweden)

Abdul Kadir Muhammad

2017-03-01

Full Text Available The purposes of this research are to formulate theequations of motion of the system, to develop computationalcodes by a finite element analysis in order to perform dynamicssimulation with vibration control, to propose an effective controlscheme using active-force (AF control a flexible single-linkmanipulator. The system used in this paper consists of analuminum beam as a flexible link, a clamp-part, a servo motor torotate the link and a piezoelectric actuator to control vibration.Computational codes on time history responses, FFT (FastFourier Transform processing and eigenvalues-eigenvectorsanalysis were developed to calculate dynamic behavior of thelink. Furthermore, the AF control was designed to drive thepiezoelectric actuator. Calculated results have revealed that thevibration of the system can be suppressed effectively

Command and Data Handling Branch Internship

Science.gov (United States)

Billings, Rachel Mae

2016-01-01

Modular Integrated Stackable Layers (MISL) is a computer system designed for simple, fast, and cost effective flexible reconfiguration in space environments such as the ISS and Orion projects for various uses. Existing applications include wireless and wired communications, data acquisition and instrumentation, and camera systems, and potential applications include bus protocol converters and subsystem control. MISL is based on Texas Instruments (TI)' MSP430 16-bit ultra-low-power microcontroller device. The purpose of my project was to integrate the MISL system with a liquid crystal display (LCD) touchscreen. The LCD, manufactured by Crystalfontz and part number CFAF320240F-035T-TS, is a 320 by 240 RGB resistive color screen including an optional carrier board. The vast majority of the project was done with Altium Designer, a tool for printed circuit board (PCB) schematic capture, 3D design, and FPGA (Field Programmable Gate Array) development. The new PCB was to allow the LCD to directly stack to the rest of MISL. Research was done with datasheets for the TI microcontroller and touchscreen display in order to meet desired hardware specifications. Documentation on prior MISL projects was also utilized. The initial step was to create a schematic for the LCD, power bus, and data bus connections between components. A layout was then designed with the required physical dimensions, routed traces and vias, power and ground planes, layer stacks, and other specified design rules such as plane clearance and hole size. Multiple consultation sessions were held with Hester Yim, the technical discipline lead for the Command and Data Handling Branch, and Christy Herring, the lead PCB layout designer in the Electronic Design and Manufacturing Branch in order to ensure proper configuration. At the moment, the PCB is awaiting revision by the latter-mentioned branch. Afterwards, the board will begin to undergo the manufacturing and testing process. Throughout the internship at

Development of Flexible Active Power Control Strategies for Grid-Connected Photovoltaic Inverters by Modifying MPPT Algorithms

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2017-01-01

As the penetration level of grid-connected PV systems increases, more advanced control functionality is demanded. In order to ensure smooth and friendly grid integration as well as enable more PV installations, the power generated by PV systems needs to be flexible and capable of: 1) limiting...... strategies for grid-connected PV inverters by modifying maximum power point tracking algorithms, where the PV power is regulated by changing the operating point of the PV system. In this way, no extra equipment is needed, being a cost-effective solution. Experiments on a 3-kW grid-connected PV system have...... the maximum feed-in power, 2) ensuring a smooth change rate, and 3) providing a power reserve. Besides, such flexible power control functionalities have to be achieved in a cost-effective way in order to ensure the competitiveness of solar energy. Therefore, this paper explores flexible active power control...

Tracking control of the hydraulically actuated flexible manipulator

International Nuclear Information System (INIS)

Kwon, D.S.; Babcock, S.M.; Burks, B.L.; Kress, R.L.

1995-01-01

The remediation of single-shell radioactive waste storage tanks is one of the urgent tasks of the Department of Energy that challenge state-of-the-art equipment and methods. The use of long-reach manipulators is being seriously considered for this remediation task. Because high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems are expected to use hydraulic actuators and to exhibit significant structural flexibility. The controller has been designed to compensate for the hydraulic actuator dynamics by using a load-compensated velocity feedforward loop and to increase the bandwidth by using a pressure feed backloop. Shaping filter techniques have been applied as a feedforward controller to avoid structural vibrations during operation. Among various types of shaping filter methods investigated an approach, referred to as a ''feedforward simulation filter'' that uses embedded simulation, has been presented

Composite Sliding Mode Control for a Free-Floating Space Rigid-Flexible Coupling Manipulator System

OpenAIRE

Congqing, Wang; Pengfei, Wu; Xin, Zhou; Xiwu, Pei

2013-01-01

The flexible space manipulator is a highly nonlinear and coupled dynamic system. This paper proposes a novel composite sliding mode control to deal with the vibration suppression and trajectory tracking of a free-floating space rigid-flexible coupling manipulator with a rigid payload. First, the dynamic equations of this system are established by using Lagrange and assumed mode methods and in the meantime this dynamic modelling allows consideration of the modelling errors, the external distur...

Rigid dietary control, flexible dietary control, and intuitive eating: Evidence for their differential relationship to disordered eating and body image concerns.

Science.gov (United States)

Linardon, Jake; Mitchell, Sarah

2017-08-01

This study aimed to replicate and extend from Tylka, Calogero, and Daníelsdóttir (2015) findings by examining the relationship between rigid control, flexible control, and intuitive eating on various indices of disordered eating (i.e., binge eating, disinhibition) and body image concerns (i.e., shape and weight over-evaluation, body checking, and weight-related exercise motivations). This study also examined whether the relationship between intuitive eating and outcomes was mediated by dichotomous thinking and body appreciation. Analysing data from a sample of 372 men and women recruited through the community, this study found that, in contrast to rigid dietary control, intuitive eating uniquely and consistently predicted lower levels of disordered eating and body image concerns. This intuitive eating-disordered eating relationship was mediated by low levels of dichotomous thinking and the intuitive eating-body image relationship was mediated by high levels of body appreciation. Flexible control predicted higher levels of body image concerns and lower levels of disordered eating only when rigid control was accounted for. Findings suggest that until the adaptive properties of flexible control are further elucidated, it may be beneficial to promote intuitive eating within public health approaches to eating disorder prevention. In addition to this, particular emphasis should also be made toward promoting body acceptance and eradicating a dichotomous thinking style around food and eating. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multistable decision switches for flexible control of epigenetic differentiation.

Directory of Open Access Journals (Sweden)

Raúl Guantes

2008-11-01

Full Text Available It is now recognized that molecular circuits with positive feedback can induce two different gene expression states (bistability under the very same cellular conditions. Whether, and how, cells make use of the coexistence of a larger number of stable states (multistability is however largely unknown. Here, we first examine how autoregulation, a common attribute of genetic master regulators, facilitates multistability in two-component circuits. A systematic exploration of these modules' parameter space reveals two classes of molecular switches, involving transitions in bistable (progression switches or multistable (decision switches regimes. We demonstrate the potential of decision switches for multifaceted stimulus processing, including strength, duration, and flexible discrimination. These tasks enhance response specificity, help to store short-term memories of recent signaling events, stabilize transient gene expression, and enable stochastic fate commitment. The relevance of these circuits is further supported by biological data, because we find them in numerous developmental scenarios. Indeed, many of the presented information-processing features of decision switches could ultimately demonstrate a more flexible control of epigenetic differentiation.

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

Science.gov (United States)

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.

Flexible supercapacitors with high areal capacitance based on hierarchical carbon tubular nanostructures

Science.gov (United States)

Zhang, Haitao; Su, Hai; Zhang, Lei; Zhang, Binbin; Chun, Fengjun; Chu, Xiang; He, Weidong; Yang, Weiqing

2016-11-01

Hierarchical structure design can greatly enhance the unique properties of primary material(s) but suffers from complicated preparation process and difficult self-assembly of materials with different dimensionalities. Here we report on the growth of single carbon tubular nanostructures with hierarchical structure (hCTNs) through a simple method based on direct conversion of carbon dioxide. Resorting to in-situ transformation and self-assembly of carbon micro/nano-structures, the obtained hCTNs are blood-like multichannel hierarchy composed of one large channel across the hCTNs and plenty of small branches connected to each other. Due to the unique pore structure and high surface area, these hCTN-based flexible supercapacitors possess the highest areal capacitance of ∼320 mF cm-2, as well as good rate-capability and excellent cycling stability (95% retention after 2500 cycles). It was established that this method can control the morphology, size, and density of hCTNs and effectively construct hCTNs well anchored to the various substrates. Our work unambiguously demonstrated the potential of hCTNs for large flexible supercapacitors and integrated energy management electronics.

DAMARIS – a flexible and open software platform for NMR spectrometer control

OpenAIRE

Gädke, Achim; Rosenstihl, Markus; Schmitt, Christopher; Stork, Holger; Nestle, Nikolaus

2016-01-01

Home-built NMR spectrometers with self-written control software have a long tradition in porous media research. Advantages of such spectrometers are not just lower costs but also more flexibility in developing new experiments (while commercial NMR systems are typically optimized for standard applications such as spectroscopy, imaging or quality control applications). Increasing complexity of computer operating systems, higher expectations with respect to user-friendliness and graphical use...

Reduction of interior sound fields in flexible cylinders by active vibration control

Science.gov (United States)

Jones, J. D.; Fuller, C. R.

1988-01-01

The mechanisms of interior sound reduction through active control of a thin flexible shell's vibrational response are presently evaluated in view of an analytical model. The noise source is a single exterior acoustic monopole. The active control model is evaluated for harmonic excitation; the results obtained indicate spatially-averaged noise reductions in excess of 20 dB over the source plane, for acoustic resonant conditions inside the cavity.

Gibberellin Promotes Shoot Branching in the Perennial Woody Plant Jatropha curcas.

Science.gov (United States)

Ni, Jun; Gao, Congcong; Chen, Mao-Sheng; Pan, Bang-Zhen; Ye, Kaiqin; Xu, Zeng-Fu

2015-08-01

Strigolactone (SL), auxin and cytokinin (CK) interact to regulate shoot branching. CK has long been considered to be the only key phytohormone to promote lateral bud outgrowth. Here we report that gibberellin also acts as a positive regulator in the control of shoot branching in the woody plant Jatropha curcas. We show that gibberellin and CK synergistically promote lateral bud outgrowth, and that both hormones influence the expression of putative branching regulators, J. curcas BRANCHED1 and BRANCHED2, which are key transcription factors maintaining bud dormancy. Moreover, treatment with paclobutrazol, an inhibitor of de novo gibberellin biosynthesis, significantly reduced the promotion of bud outgrowth by CK, suggesting that gibberellin is required for CK-mediated axillary bud outgrowth. In addition, SL, a plant hormone involved in the repression of shoot branching, acted antagonistically to both gibberellin and CK in the control of lateral bud outgrowth. Consistent with this, the expression of JcMAX2, a J. curcas homolog of Arabidopsis MORE AXILLARY GROWTH 2 encoding an F-box protein in the SL signaling pathway, was repressed by gibberellin and CK treatment. We also provide physiological evidence that gibberellin also induces shoot branching in many other trees, such as papaya, indicating that a more complicated regulatory network occurs in the control of shoot branching in some perennial woody plants. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

Robust high-precision attitude control for flexible spacecraft with improved mixed H2/H∞ control strategy under poles assignment constraint

Science.gov (United States)

Liu, Chuang; Ye, Dong; Shi, Keke; Sun, Zhaowei

2017-07-01

A novel improved mixed H2/H∞ control technique combined with poles assignment theory is presented to achieve attitude stabilization and vibration suppression simultaneously for flexible spacecraft in this paper. The flexible spacecraft dynamics system is described and transformed into corresponding state space form. Based on linear matrix inequalities (LMIs) scheme and poles assignment theory, the improved mixed H2/H∞ controller does not restrict the equivalence of the two Lyapunov variables involved in H2 and H∞ performance, which can reduce conservatives compared with traditional mixed H2/H∞ controller. Moreover, it can eliminate the coupling of Lyapunov matrix variables and system matrices by introducing slack variable that provides additional degree of freedom. Several simulations are performed to demonstrate the effectiveness and feasibility of the proposed method in this paper.

Lateral vibration control of a flexible overcritical rotor via an active gas bearing – Theoretical and experimental comparisons

DEFF Research Database (Denmark)

Pierart Vásquez, Fabián Gonzalo; Santos, Ilmar

2016-01-01

The lack of damping of radial gas bearings leads to high vibration levels of a rotor supported by this type of bearing when crossing resonant areas. This is even more relevant for flexible rotors, as studied in this work. In order to reduce these high vibration levels, an active gas bearing...... is proposed. The control action of this active bearing is selected based on two different strategies: a simple proportional integral derivative controller and an optimal controller. Both controllers are designed based on a theoretical model previously presented. The dynamics of the flexible rotor are modelled......-based controllers are compared against experimental results, showing good agreement. Theoretical and experimental results show a significant increase in the damping ratio of the system, enabling the flexible rotor to run safely across the critical speeds and up to 12,000rev/min, i.e. 50 percent over the second...

Stabilizing model predictive control of a gantry crane based on flexible set-membership constraints

NARCIS (Netherlands)

Iles, Sandor; Lazar, M.; Kolonic, Fetah; Jadranko, Matusko

2015-01-01

This paper presents a stabilizing distributed model predictive control of a gantry crane taking into account the variation of cable length. The proposed algorithm is based on the off-line computation of a sequence of 1-step controllable sets and a condition that enables flexible convergence towards

BATS, the readout control of UA1

Energy Technology Data Exchange (ETDEWEB)

Botlo, M.; Dorenbosch, J.; Jimack, M.; Szoncso, F.; Taurok, A.; Walzel, G. (European Organization for Nuclear Research, Geneva (Switzerland))

1991-04-15

A steadily rising luminosity and different readout architectures for the various detector systems of UA1 required a new data flow control to minimize the dead time. BATS, a finite state machine conceived around two microprocessors in a single VME crate, improved flexibility and reliability. Compatibility with BATS streamlined all readout branches. BATS also proved to be a valuable asset in spotting readout problems and previously undetected data flow bottlenecks. (orig.).

Pulsed positive corona streamer propagation and branching

International Nuclear Information System (INIS)

Veldhuizen, E.M. van; Rutgers, W.R.

2002-01-01

The propagation and branching of pulsed positive corona streamers in a short gap is observed with high resolution in space and time. The appearance of the pre-breakdown phenomena can be controlled by the electrode configuration, the gas composition and the impedance of the pulsed power circuit. In a point-wire gap the positive corona shows much more branching than in the parallel plane gap with a protrusion. In air, the branching is more pronounced than in argon. The pulsed power circuit appears to operate in two modes, either as an inductive circuit creating a lower number of thick streamers or as a resistive circuit giving a higher number of thin streamers. A possible cause for branching is electrostatic repulsion of two parts of the streamer head. The electric field at the streamer head is limited, the maximum values found are ∼170 kV cm -1 in air and ∼100 kV cm -1 in argon. At these maximum field strengths, the electrons have 5-10 eV energy, so the ionization is dominated by two-step processes. Differences between argon and ambient air in the field strength at which streamers propagate are ascribed to the difference in de-excitation processes in noble and molecular gases. The fact that the pulsed power circuit can control the streamer structure is important for applications, but this effect must also be taken into account in fundamental studies of streamer propagation and branching. (author)

Pulsed positive corona streamer propagation and branching

Energy Technology Data Exchange (ETDEWEB)

Veldhuizen, E.M. van [Department of Physics, Technische Universiteit Eindhoven, Eindhoven (Netherlands)]. E-mail: e.m.v.veldhuizen@tue.nl; Rutgers, W.R. [Department of Physics, Technische Universiteit Eindhoven, Eindhoven (Netherlands)

2002-09-07

The propagation and branching of pulsed positive corona streamers in a short gap is observed with high resolution in space and time. The appearance of the pre-breakdown phenomena can be controlled by the electrode configuration, the gas composition and the impedance of the pulsed power circuit. In a point-wire gap the positive corona shows much more branching than in the parallel plane gap with a protrusion. In air, the branching is more pronounced than in argon. The pulsed power circuit appears to operate in two modes, either as an inductive circuit creating a lower number of thick streamers or as a resistive circuit giving a higher number of thin streamers. A possible cause for branching is electrostatic repulsion of two parts of the streamer head. The electric field at the streamer head is limited, the maximum values found are {approx}170 kV cm{sup -1} in air and {approx}100 kV cm{sup -1} in argon. At these maximum field strengths, the electrons have 5-10 eV energy, so the ionization is dominated by two-step processes. Differences between argon and ambient air in the field strength at which streamers propagate are ascribed to the difference in de-excitation processes in noble and molecular gases. The fact that the pulsed power circuit can control the streamer structure is important for applications, but this effect must also be taken into account in fundamental studies of streamer propagation and branching. (author)

Summary of Guidelines for Infection Prevention and Control for Flexible Gastrointestinal Endoscopy

Directory of Open Access Journals (Sweden)

Lawrence Hookey

2013-01-01

Full Text Available BACKGROUND: High-quality processes to ensure infection prevention and control in the delivery of safe endoscopy services are essential. In 2010, the Public Health Agency of Canada and the Canadian Association of Gastroenterology (CAG developed a Canadian guideline for the reprocessing of flexible gastrointestinal endoscopy equipment.

[Branches of the National Institute of Hygiene].

Science.gov (United States)

Gromulska, Marta

2008-01-01

National Epidemiological Institute (National Institute of Hygiene, from 7th September 1923) was established in 1918 in Warsaw and acted at national level. Its actions in the field of diseases combat were supported by bacteriological stations and vaccine production in voivodeship cities, which were taken charge of by the state, and names "National Epidemiological Institutes". According to the ministers resolution from 6th July 1921,Epidemiological Institutes were merged to National Central Epidemiological Institutes (PZH), the epidemiological institutes outside Warsaw were named branches, which were to be located in every voivodeship city, according to the initial organizational resolutions. There were country branches of NCEI in: Cracow, Lwów, Lódź, Toruń, Lublin, and Wilno in the period 1919-1923. New branches in Poznań (1925), Gdynia(1934), Katowice (Voivodeship Institute of Hygiene (1936), Luck (1937), Stanisławów (1937), Kielce(1938), and Brześć/Bug (Municipal Station acting as branch of National Central Epidemiological Institute. Branches were subordinated to NCEI-PZH) in Warsaw where action plans and unified research and diagnostic method were established and annual meeting of the country branches managers took place. All branches cooperated with hospitals, national health services, district general practitioners and administration structure in control of infectious diseases. In 1938, the post of branch inspector was established, the first of whom was Feliks Przesmycki PhD. Branches cooperated also with University of Cracow, University of Lwów and University of Wilno. In 1935, National Institutes of Food Research was incorporated in PZH, Water Department was established, and these areas of activity began to develop in the branches accordingly. In 1938 there were 13 branches of PZH, and each had three divisions: bacteriological, food research and water research. Three branches in Cracow, Kielce and Lublin worked during World War II under German

ZeroSDN: A Message Bus for Flexible and Light-weight Network Control Distribution in SDN

OpenAIRE

Dürr, Frank; Kohler, Thomas; Grunert, Jonas; Kutzleb, Andre

2016-01-01

Recent years have seen an evolution of SDN control plane architectures, starting from simple monolithic controllers, over modular monolithic controllers, to distributed controllers. We observe, however, that today's distributed controllers still exhibit inflexibility with respect to the distribution of control logic. Therefore, we propose a novel architecture of a distributed SDN controller in this paper, providing maximum flexibility with respect to distribution. Our architecture splits cont...

Sleep Deprivation Diminishes Attentional Control Effectiveness and Impairs Flexible Adaptation to Changing Conditions.

Science.gov (United States)

Whitney, Paul; Hinson, John M; Satterfield, Brieann C; Grant, Devon A; Honn, Kimberly A; Van Dongen, Hans P A

2017-11-22

Insufficient sleep is a global public health problem resulting in catastrophic accidents, increased mortality, and hundreds of billions of dollars in lost productivity. Yet the effect of sleep deprivation (SD) on decision making and performance is often underestimated by fatigued individuals and is only beginning to be understood by scientists. The deleterious impact of SD is frequently attributed to lapses in vigilant attention, but this account fails to explain many SD-related problems, such as loss of situational awareness and perseveration. Using a laboratory study protocol, we show that SD individuals can maintain information in the focus of attention and anticipate likely correct responses, but their use of such a top-down attentional strategy is less effective at preventing errors caused by competing responses. Moreover, when the task environment requires flexibility, performance under SD suffers dramatically. The impairment in flexible shifting of attentional control we observed is distinct from lapses in vigilant attention, as corroborated by the specificity of the influence of a genetic biomarker, the dopaminergic polymorphism DRD2 C957T. Reduced effectiveness of top-down attentional control under SD, especially when conditions require flexibility, helps to explain maladaptive performance that is not readily explained by lapses in vigilant attention.

Input preshaping with frequency domain information for flexible-link manipulator control

Science.gov (United States)

Tzes, Anthony; Englehart, Matthew J.; Yurkovich, Stephen

1989-01-01

The application of an input preshaping scheme to flexible manipulators is considered. The resulting control corresponds to a feedforward term that convolves in real-time the desired reference input with a sequence of impulses and produces a vibration free output. The robustness of the algorithm with respect to injected disturbances and modal frequency variations is not satisfactory and can be improved by convolving the input with a longer sequence of impulses. The incorporation of the preshaping scheme to a closed-loop plant, using acceleration feedback, offers satisfactory disturbance rejection due to feedback and cancellation of the flexible mode effects due to the preshaping. A frequency domain identification scheme is used to estimate the modal frequencies on-line and subsequently update the spacing between the impulses. The combined adaptive input preshaping scheme provides the fastest possible slew that results in a vibration free output.

Self-organization principles result in robust control of flexible manufacturing systems

DEFF Research Database (Denmark)

Nature shows us in our daily life how robust, flexible and optimal self-organized modular constructions work in complex physical, chemical and biological systems, which successfully adapt to new and unexpected situations. A promising strategy is therefore to use such self-organization and pattern...... problems with several autonomous robots and several targets are considered as model of flexible manufacturing systems. Each manufacturing target has to be served in a given time interval by one and only one robot and the total working costs have to be minimized (or total winnings maximized). A specifically...... constructed dynamical system approach (coupled selection equations) is used which is based on pattern formation principles and results in fault resistant and robust behaviour. An important feature is that this type of control also guarantees feasiblitiy of the assignment solutions. In previous work...

Branches of the Facial Artery.

Science.gov (United States)

Hwang, Kun; Lee, Geun In; Park, Hye Jin

2015-06-01

The aim of this study is to review the name of the branches, to review the classification of the branching pattern, and to clarify a presence percentage of each branch of the facial artery, systematically. In a PubMed search, the search terms "facial," AND "artery," AND "classification OR variant OR pattern" were used. The IBM SPSS Statistics 20 system was used for statistical analysis. Among the 500 titles, 18 articles were selected and reviewed systematically. Most of the articles focused on "classification" according to the "terminal branch." Several authors classified the facial artery according to their terminal branches. Most of them, however, did not describe the definition of "terminal branch." There were confusions within the classifications. When the inferior labial artery was absent, 3 different types were used. The "alar branch" or "nasal branch" was used instead of the "lateral nasal branch." The angular branch was used to refer to several different branches. The presence as a percentage of each branch according to the branches in Gray's Anatomy (premasseteric, inferior labial, superior labial, lateral nasal, and angular) varied. No branch was used with 100% consistency. The superior labial branch was most frequently cited (95.7%, 382 arteries in 399 hemifaces). The angular branch (53.9%, 219 arteries in 406 hemifaces) and the premasseteric branch were least frequently cited (53.8%, 43 arteries in 80 hemifaces). There were significant differences among each of the 5 branches (P < 0.05) except between the angular branch and the premasseteric branch and between the superior labial branch and the inferior labial branch. The authors believe identifying the presence percentage of each branch will be helpful for surgical procedures.

Magnetic fish-robot based on multi-motion control of a flexible magnetic actuator.

Science.gov (United States)

Kim, Sung Hoon; Shin, Kyoosik; Hashi, Shuichiro; Ishiyama, Kazushi

2012-09-01

This paper presents a biologically inspired fish-robot driven by a single flexible magnetic actuator with a rotating magnetic field in a three-axis Helmholtz coil. Generally, magnetic fish-robots are powered by alternating and gradient magnetic fields, which provide a single motion such as bending the fish-robot's fins. On the other hand, a flexible magnetic actuator driven by an external rotating magnetic field can create several gaits such as the bending vibration, the twisting vibration, and their combination. Most magnetic fish-like micro-robots do not have pectoral fins on the side and are simply propelled by the tail fin. The proposed robot can swim and perform a variety of maneuvers with the addition of pectoral fins and control of the magnetic torque direction. In this paper, we find that the robot's dynamic actuation correlates with the magnetic actuator and the rotating magnetic field. The proposed robot is also equipped with new features, such as a total of six degrees of freedom, a new control method that stabilizes posture, three-dimensional swimming, a new velocity control, and new turning abilities.

Magnetic fish-robot based on multi-motion control of a flexible magnetic actuator

International Nuclear Information System (INIS)

Kim, Sung Hoon; Hashi, Shuichiro; Ishiyama, Kazushi; Shin, Kyoosik

2012-01-01

This paper presents a biologically inspired fish-robot driven by a single flexible magnetic actuator with a rotating magnetic field in a three-axis Helmholtz coil. Generally, magnetic fish-robots are powered by alternating and gradient magnetic fields, which provide a single motion such as bending the fish-robot's fins. On the other hand, a flexible magnetic actuator driven by an external rotating magnetic field can create several gaits such as the bending vibration, the twisting vibration, and their combination. Most magnetic fish-like micro-robots do not have pectoral fins on the side and are simply propelled by the tail fin. The proposed robot can swim and perform a variety of maneuvers with the addition of pectoral fins and control of the magnetic torque direction. In this paper, we find that the robot's dynamic actuation correlates with the magnetic actuator and the rotating magnetic field. The proposed robot is also equipped with new features, such as a total of six degrees of freedom, a new control method that stabilizes posture, three-dimensional swimming, a new velocity control, and new turning abilities. (paper)

Tillering and panicle branching genes in rice.

Science.gov (United States)

Liang, Wei-hong; Shang, Fei; Lin, Qun-ting; Lou, Chen; Zhang, Jing

2014-03-01

Rice (Oryza sativa L.) is one of the most important staple food crops in the world, and rice tillering and panicle branching are important traits determining grain yield. Since the gene MONOCULM 1 (MOC 1) was first characterized as a key regulator in controlling rice tillering and branching, great progress has been achieved in identifying important genes associated with grain yield, elucidating the genetic basis of yield-related traits. Some of these important genes were shown to be applicable for molecular breeding of high-yielding rice. This review focuses on recent advances, with emphasis on rice tillering and panicle branching genes, and their regulatory networks. Copyright © 2013 Elsevier B.V. All rights reserved.

Integral Manifold in System Design with Application to Flexible Link Robot Control

Science.gov (United States)

1988-06-01

environment. I am very grateful to my advisor . Professor Kokotovic. whose insight and guidance in my research work led me to the beginning of my...MANIFOLD IN SVSTEM DESIGN WITH RPLICATION TT 2Z2 FLEXIBLE LINK ROBO (U) ILLINOIS UNIV AT URBANA DECISION AND CONTROL LAB H C TSENG JUN 98

A stretchable polymer-carbon nanotube composite electrode for flexible lithium-ion batteries: porosity engineering by controlled phase separation

Energy Technology Data Exchange (ETDEWEB)

Lee, Hojun; Yoo, Jung-Keun; Jung, Yeon Sik [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of); Park, Jong-Hyun [Material R and D Department, LG Display Co., Ltd., Paju-si, Gyeonggi-do (Korea, Republic of); Kim, Jin Ho [Icheon Branch, Korea Institute of Ceramic Engineering and Technology, Icheon-si, Gyeonggi-do (Korea, Republic of); Kang, Kisuk [Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)

2012-08-15

Flexible energy-storage devices have attracted growing attention with the fast development of bendable electronic systems. However, it still remains a challenge to find reliable electrode materials with both high mechanical flexibility/toughness and excellent electron and lithium-ion conductivity. This paper reports the fabrication and characterization of highly porous, stretchable, and conductive polymer nanocomposites embedded with carbon nanotubes (CNTs) for application in flexible lithium-ion batteries. The systematic optimization of the porous morphology is performed by controllably inducing the phase separation of polymethylmethacrylate (PMMA) in polydimethylsiloxane (PDMS) and removing PMMA, in order to generate well-controlled pore networks. It is demonstrated that the porous CNT-embedded PDMS nanocomposites are capable of good electrochemical performance with mechanical flexibility, suggesting these nanocomposites could be outstanding anode candidates for use in flexible lithium-ion batteries. The optimization of the pore size and the volume fraction provides higher capacity by nearly seven-fold compared to a nonporous nanocomposite. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Novel adaptive neural control of flexible air-breathing hypersonic vehicles based on sliding mode differentiator

Directory of Open Access Journals (Sweden)

Bu Xiangwei

2015-08-01

Full Text Available A novel adaptive neural control strategy is exploited for the longitudinal dynamics of a generic flexible air-breathing hypersonic vehicle (FAHV. By utilizing functional decomposition method, the dynamics of FAHV is decomposed into the velocity subsystem and the altitude subsystem. For each subsystem, only one neural network is employed for the unknown function approximation. To further reduce the computational burden, minimal-learning parameter (MLP technology is used to estimate the norm of ideal weight vectors rather than their elements. By introducing sliding mode differentiator (SMD to estimate the newly defined variables, there is no need for the strict-feedback form and virtual controller. Hence the developed control law is considerably simpler than the ones derived from back-stepping scheme. Finally, simulation studies are made to illustrate the effectiveness of the proposed control approach in spite of the flexible effects, system uncertainties and varying disturbances.

Load and Flexibility Models for Distribution Grid Management

DEFF Research Database (Denmark)

Kouzelis, Konstantinos

to advanced metering and control infrastructure investments. These investments will transform distribution networks into smarter" grids which will facilitate flexible load/generation control in return for financial and reliability benefits to electricity consumers. The theoretical idea of modernising the grid...... involve lack of generic load forecasts, need for flexible load/generation estimation techniques from smart meter measurements, deficiencies in online load distribution observability, and, finally, energy market compatible control algorithms which treat consumer flexibility in a fair manner. These modules...... congestions, is proposed. In the first step, a central controller manages flexibility proactively, whereas in the second step a decentralised control scheme deals with flexibility reactively. Both controllers are designed in such a way, that compatibility with contemporary markets is assured, while special...

SlCCD7 controls strigolactone biosynthesis, shoot branching and mycorrhiza-induced apocarotenoid formation in tomato.

NARCIS (Netherlands)

Vogel, J.T.; Walter, M.H.; Giavalisco, P.; Lytovchenko, A.; Kohlen, W.; Charnikhova, T.; Simkin, A.J.; Goulet, C.; Strack, D.; Bouwmeester, H.J.; Fernie, A.R.; Klee, H.J.

2010-01-01

The regulation of shoot branching is an essential determinant of plant architecture, integrating multiple external and internal signals. One of the signaling pathways regulating branching involves the MAX (more axillary branches) genes. Two of the genes within this pathway, MAX3/CCD7 and MAX4/CCD8,

Controlling flexible robot arms using a high speed dynamics process

Science.gov (United States)

Jain, Abhinandan (Inventor); Rodriguez, Guillermo (Inventor)

1992-01-01

Described here is a robot controller for a flexible manipulator arm having plural bodies connected at respective movable hinges, and flexible in plural deformation modes. It is operated by computing articulated body qualities for each of the bodies from the respective modal spatial influence vectors, obtaining specified body forces for each of the bodies, and computing modal deformation accelerations of the nodes and hinge accelerations of the hinges from the specified body forces, from the articulated body quantities and from the modal spatial influence vectors. In one embodiment of the invention, the controller further operates by comparing the accelerations thus computed to desired manipulator motion to determine a motion discrepancy, and correcting the specified body forces so as to reduce the motion discrepancy. The manipulator bodies and hinges are characterized by respective vectors of deformation and hinge configuration variables. Computing modal deformation accelerations and hinge accelerations is carried out for each of the bodies, beginning with the outermost body by computing a residual body force from a residual body force of a previous body, computing a resultant hinge acceleration from the body force, and then, for each one of the bodies beginning with the innermost body, computing a modal body acceleration from a modal body acceleration of a previous body, computing a modal deformation acceleration and hinge acceleration from the resulting hinge acceleration and from the modal body acceleration.

Genetic algorithm based active vibration control for a moving flexible smart beam driven by a pneumatic rod cylinder

Science.gov (United States)

Qiu, Zhi-cheng; Shi, Ming-li; Wang, Bin; Xie, Zhuo-wei

2012-05-01

A rod cylinder based pneumatic driving scheme is proposed to suppress the vibration of a flexible smart beam. Pulse code modulation (PCM) method is employed to control the motion of the cylinder's piston rod for simultaneous positioning and vibration suppression. Firstly, the system dynamics model is derived using Hamilton principle. Its standard state-space representation is obtained for characteristic analysis, controller design, and simulation. Secondly, a genetic algorithm (GA) is applied to optimize and tune the control gain parameters adaptively based on the specific performance index. Numerical simulations are performed on the pneumatic driving elastic beam system, using the established model and controller with tuned gains by GA optimization process. Finally, an experimental setup for the flexible beam driven by a pneumatic rod cylinder is constructed. Experiments for suppressing vibrations of the flexible beam are conducted. Theoretical analysis, numerical simulation and experimental results demonstrate that the proposed pneumatic drive scheme and the adopted control algorithms are feasible. The large amplitude vibration of the first bending mode can be suppressed effectively.

Feedback-controlled lubrication for reducing the lateral vibration of flexible rotors supported by tilting-pad journal bearings

DEFF Research Database (Denmark)

Salazar, Jorge Andrés González; Santos, Ilmar

2015-01-01

function is optimized in the stabilizing gain domain and then chosen from a subdomain imposed by servovalve restrictions. This work demonstrates enhancements of the dynamic response of flexible rotor-bearing systems supported by an active tilting-pad journal bearing by means of the feedback......The feedback-controlled lubrication regime, based on a model-free designed proportional–derivative controller, is experimentally investigated in a flexible rotor mounted on an actively-lubricated tilting-pad journal bearing. With such a lubrication regime, both the resulting pressure distribution...

Planar rigid-flexible coupling spacecraft modeling and control considering solar array deployment and joint clearance

Science.gov (United States)

Li, Yuanyuan; Wang, Zilu; Wang, Cong; Huang, Wenhu

2018-01-01

Based on Nodal Coordinate Formulation (NCF) and Absolute Nodal Coordinate Formulation (ANCF), this paper establishes rigid-flexible coupling dynamic model of the spacecraft with large deployable solar arrays and multiple clearance joints to analyze and control the satellite attitude under deployment disturbance. Considering torque spring, close cable loop (CCL) configuration and latch mechanisms, a typical spacecraft composed of a rigid main-body described by NCF and two flexible panels described by ANCF is used as a demonstration case. Nonlinear contact force model and modified Coulomb friction model are selected to establish normal contact force and tangential friction model, respectively. Generalized elastic force are derived and all generalized forces are defined in the NCF-ANCF frame. The Newmark-β method is used to solve system equations of motion. The availability and superiority of the proposed model is verified through comparing with numerical co-simulations of Patran and ADAMS software. The numerical results reveal the effects of panel flexibility, joint clearance and their coupling on satellite attitude. The effects of clearance number, clearance size and clearance stiffness on satellite attitude are investigated. Furthermore, a proportional-differential (PD) attitude controller of spacecraft is designed to discuss the effect of attitude control on the dynamic responses of the whole system.

Attitude dynamics and control of spacecraft with a partially filled liquid tank and flexible panels

Science.gov (United States)

Liu, Feng; Yue, Baozeng; Zhao, Liangyu

2018-02-01

A liquid-filled flexible spacecraft is essentially a time-variant fully-coupled system, whose dynamics characteristics are closely associated with its motion features. This paper focuses on the mathematical modelling and attitude control of the spacecraft coupled with fuel sloshing dynamics and flexible solar panels vibration. The slosh motion is represented by a spherical pendulum, whose motion description method is improved by using split variable operation. Benefiting from this improvement, the nonlinear lateral sloshing and the rotary sloshing as well as the rigid motion of a liquid respect to the spacecraft can be approximately described. The assumed modes discretization method has been adopted to approximate the elastic displacements of the attached panels, and the coupled dynamics is derived by using the Lagrangian formulation. A variable substitution method is proposed to obtain the apparently-uncoupled mathematical model of the rigid-flexible-liquid spacecraft. After linearization, this model can be directly used for designing Lyapunov output-feedback attitude controller (OFAC). With only torque actuators, and attitude and rate sensors installed, this kind of attitude controller, as simulation results show, is capable of not only bringing the spacecraft to the desired orientation, but also suppressing the effect of flex and slosh on the attitude motion of the spacecraft.

Branch formation induced by microbeam irradiation of Adiantum protonemata

International Nuclear Information System (INIS)

Wada, M.

1998-01-01

Branches were induced in centrifuged Adiantum protonemal cells by partial irradiation with polarized red light. Nuclear behavior and microtubule pattern change during branch formation were investigated. A branch formed at any part where a red microbeam was focused along a long apical cell. The nucleus moved towards the irradiated area and remained there until a branch developed. The pattern of microtubules changed from parallel to oblique at the irradiated area and then a transverse arrangement of microtubules appeared on both sides of the area. It appeared as if the nucleus was suspended between two microtubule rings. This nuclear behavior and the changes in microtubule pattern were different from those observed during branch formation under whole cell irradiation. From the results of this work we suggest that there is an importance for precise control of experimental conditions

Detailed requirements and constraints for the control of flexibility

DEFF Research Database (Denmark)

Hänninen, Seppo; Kyritsis, Anastasios; Abdulhadi, Ibrahim

2015-01-01

between day-ahead production and consumption schedule and will leave energy markets with higher and less predictable need for balancing power. The actors involved in the future grid control are balance responsible Party (BRP), cell system operator (CSO), cell operational information system (COIS...... and voltage control now and in the future. Regarding the flexibility of electricity generation, gas turbines and other heat motors as reciprocating engines can be started quickest. The speed of power change is clearly the highest for heat motors and their minimum power is low. Also steam and combined heat...... and power plants can be utilised in the relatively quick increasing of the electricity generation. Slower power changes are possible also with the nuclear power but they cannot be carried out continuously. The regulation characteristics of hydro power are superb in comparison to the other electricity...

Fuzzy based attitude controller for flexible spacecraft with on/off thrusters

Science.gov (United States)

Knapp, Roger Glenn

1993-05-01

A fuzzy-based attitude controller is designed for attitude control of a generic spacecraft with on/off thrusters. The controller is comprised of packages of rules dedicated to addressing different objectives (e.g., disturbance rejection, low fuel consumption, avoiding the excitation of flexible appendages, etc.). These rule packages can be inserted or removed depending on the requirements of the particular spacecraft and are parameterized based on vehicle parameters such as inertia or operational parameters such as the maneuvering rate. Individual rule packages can be 'weighted' relative to each other to emphasize the importance of one objective relative to another. Finally, the fuzzy controller and rule packages are demonstrated using the high-fidelity Space Shuttle Interactive On-Orbit Simulator (IOS) while performing typical on-orbit operations and are subsequently compared with the existing shuttle flight control system performance.

Branched polynomial covering maps

DEFF Research Database (Denmark)

Hansen, Vagn Lundsgaard

2002-01-01

A Weierstrass polynomial with multiple roots in certain points leads to a branched covering map. With this as the guiding example, we formally define and study the notion of a branched polynomial covering map. We shall prove that many finite covering maps are polynomial outside a discrete branch ...... set. Particular studies are made of branched polynomial covering maps arising from Riemann surfaces and from knots in the 3-sphere. (C) 2001 Elsevier Science B.V. All rights reserved.......A Weierstrass polynomial with multiple roots in certain points leads to a branched covering map. With this as the guiding example, we formally define and study the notion of a branched polynomial covering map. We shall prove that many finite covering maps are polynomial outside a discrete branch...

Rethinking 'flexibilities' in the international drug control system-Potential, precedents and models for reforms.

Science.gov (United States)

Collins, John

2017-01-24

Much international drug policy debate centres on, what policies are permissible under the international drug treaties, whether member states are openly 'breaching' these treaties by changing national regulatory frameworks and shifting priorities away from a 'war on drugs' approach, and what 'flexibility' exists for policy reform and experimentation at national and local levels. Orthodox interpretations hold that the current system is a US-led 'prohibition regime' that was constructed in an extremely repressive and restrictive manner with almost no flexibility for significant national deviations. This paper challenges these orthodox interpretive frameworks and suggests no absolute and clear dichotomy between strict adherence and 'breaches' of the international treaties. This paper uses historical analysis to highlight the flaws in orthodox policy analyses, which assume a uniform interpretation, implementation and set of policy trajectories towards a 'prohibition regime' in the 20th century. It challenges some existing legal interpretations of the treaties through recourse to historical precedents of flexible interpretation and policy prioritisation. It then examines the legal justifications currently being formulated by member states to explain a shift towards policies which, until recently, have been viewed as outside the permissible scope of the conventions. It then examines a functionalist framework for understanding the likely contours of drug diplomacy in the post-UN General Assembly Special Session (UNGASS) 2016 era. The paper highlights that, contrary to current policy discourses, the international control system has always been implemented in a 'flexible' manner. It demonstrates that drug control goals were repeatedly subsumed to security, development, political stability and population welfare imperatives, or what we might now refer to under the umbrella of 'development issues.' The paper further demonstrates that policy prioritisation, inherent treaty

Multi-rate sensor fusion-based adaptive discrete finite-time synergetic control for flexible-joint mechanical systems

International Nuclear Information System (INIS)

Xue Guang-Yue; Ren Xue-Mei; Xia Yuan-Qing

2013-01-01

This paper proposes an adaptive discrete finite-time synergetic control (ADFTSC) scheme based on a multi-rate sensor fusion estimator for flexible-joint mechanical systems in the presence of unmeasured states and dynamic uncertainties. Multi-rate sensors are employed to observe the system states which cannot be directly obtained by encoders due to the existence of joint flexibilities. By using an extended Kalman filter (EKF), the finite-time synergetic controller is designed based on a sensor fusion estimator which estimates states and parameters of the mechanical system with multi-rate measurements. The proposed controller can guarantee the finite-time convergence of tracking errors by the theoretical derivation. Simulation and experimental studies are included to validate the effectiveness of the proposed approach. (general)

Dynamic Model of a Rotating Flexible Arm-Flexible Root Mechanism Driven by a Shaft Flexible in Torsion

Directory of Open Access Journals (Sweden)

S.Z. Ismail

2006-01-01

Full Text Available This paper presents a dynamic model of a rotating flexible beam carrying a payload at its tip. The model accounts for the driving shaft and the arm root flexibilities. The finite element method and the Lagrangian dynamics are used in deriving the equations of motion with the small deformation theory assumptions and the Euler-Bernoulli beam theory. The obtained model is a nonlinear-coupled system of differential equations. The model is simulated for different combinations of shaft and root flexibilities and arm properties. The simulation results showed that the root flexibility is an important factor that should be considered in association with the arm and shaft flexibilities, as its dynamics influence the motor motion. Moreover, the effect of system non-linearity on the dynamic behavior is investigated by simulating the equivalent linearized system and it was found to be an important factor that should be considered, particularly when designing a control strategy for practical implementation.

Advanced Durable Flexible Ultra Low Outgassing Thermal Control Coatings for NASA Science Missions, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Phase I program proposes to synthesize novel nanoengineered ultra low out gassing elastomers and formulate high temperature capable flexible thermal control...

Highly controllable and green reduction of graphene oxide to flexible graphene film with high strength

International Nuclear Information System (INIS)

Wan, Wubo; Zhao, Zongbin; Hu, Han; Gogotsi, Yury; Qiu, Jieshan

2013-01-01

Graphical abstract: Highly controllable and green reduction of GO to chemical converted graphene (CCG) was achieved with sodium citrate as a facile reductant. Self-assembly of the as-made CCG sheets results in a flexible CCG film, of which the tensile strength strongly depends on the deoxygenation degree of graphene sheets. - Highlights: • Graphene was synthesized by an effective and environmentally friendly approach. • We introduced a facile X-ray diffraction analysis method to investigate the reduction process from graphene oxide to graphene. • Flexible graphene films were prepared by self-assembly of the graphene sheets. • The strength of the graphene films depends on the reduction degree of graphene. - Abstract: Graphene film with high strength was fabricated by the assembly of graphene sheets derived from graphene oxide (GO) in an effective and environmentally friendly approach. Highly controllable reduction of GO to chemical converted graphene (CCG) was achieved with sodium citrate as a facile reductant, in which the reduction process was monitored by XRD analysis and UV–vis absorption spectra. Self-assembly of the as-made CCG sheets results in a flexible CCG film. This method may open an avenue to the easy and scalable preparation of graphene film with high strength which has promising potentials in many fields where strong, flexible and electrically conductive films are highly demanded

SU-F-J-10: Sliding Mode Control of a SMA Actuated Active Flexible Needle for Medical Procedures

International Nuclear Information System (INIS)

Podder, T

2016-01-01

Purpose: In medical interventional procedures such as brachytherapy, ablative therapies and biopsy precise steering and accurate placement of needles are very important for anatomical obstacle avoidance and accurate targeting. This study presents the efficacy of a sliding mode controller for Shape Memory Alloy (SMA) actuated flexible needle for medical procedures. Methods: Second order system dynamics of the SMA actuated active flexible needle was used for deriving the sliding mode control equations. Both proportional-integral-derivative (PID) and adaptive PID sliding mode control (APIDSMC) algorithms were developed and implemented. The flexible needle was attached at the end of a 6 DOF robotic system. Through LabView programming environment, the control commands were generated using the PID and APIDSMC algorithms. Experiments with artificial tissue mimicking phantom were performed to evaluate the performance of the controller. The actual needle tip position was obtained using an electromagnetic (EM) tracking sensor (Aurora, NDI, waterloo, Canada) at a sampling period of 1ms. During experiment, external disturbances were created applying force and thermal shock to investigate the robustness of the controllers. Results: The root mean square error (RMSE) values for APIDSMC and PID controllers were 0.75 mm and 0.92 mm, respectively, for sinusoidal reference input. In the presence of external disturbances, the APIDSMC controller showed much smoother and less overshooting response compared to that of the PID controller. Conclusion: Performance of the APIDSMC was superior to the PID controller. The APIDSMC was proved to be more effective controller in compensating the SMA uncertainties and external disturbances with clinically acceptable thresholds.

SU-F-J-10: Sliding Mode Control of a SMA Actuated Active Flexible Needle for Medical Procedures

Energy Technology Data Exchange (ETDEWEB)

Podder, T [University Hospitals Case Medical Center, Cleveland, OH (United States)

2016-06-15

Purpose: In medical interventional procedures such as brachytherapy, ablative therapies and biopsy precise steering and accurate placement of needles are very important for anatomical obstacle avoidance and accurate targeting. This study presents the efficacy of a sliding mode controller for Shape Memory Alloy (SMA) actuated flexible needle for medical procedures. Methods: Second order system dynamics of the SMA actuated active flexible needle was used for deriving the sliding mode control equations. Both proportional-integral-derivative (PID) and adaptive PID sliding mode control (APIDSMC) algorithms were developed and implemented. The flexible needle was attached at the end of a 6 DOF robotic system. Through LabView programming environment, the control commands were generated using the PID and APIDSMC algorithms. Experiments with artificial tissue mimicking phantom were performed to evaluate the performance of the controller. The actual needle tip position was obtained using an electromagnetic (EM) tracking sensor (Aurora, NDI, waterloo, Canada) at a sampling period of 1ms. During experiment, external disturbances were created applying force and thermal shock to investigate the robustness of the controllers. Results: The root mean square error (RMSE) values for APIDSMC and PID controllers were 0.75 mm and 0.92 mm, respectively, for sinusoidal reference input. In the presence of external disturbances, the APIDSMC controller showed much smoother and less overshooting response compared to that of the PID controller. Conclusion: Performance of the APIDSMC was superior to the PID controller. The APIDSMC was proved to be more effective controller in compensating the SMA uncertainties and external disturbances with clinically acceptable thresholds.

Fast multiprogrammable branch driver for Micral mini-computer

International Nuclear Information System (INIS)

Kaiser, J.; Lacroix, J.

1975-01-01

This branch driver allows in association with the stack memories of the minicomputer Micral, very fast exchanges with the 7 crates of a CAMAC branch. A CAMAC program (read, write and control commands) is loaded in the IK stack memory of the Micral and executed in sequence at a rate of 1,6μs per CAMAC command. After programm execution, data may be transferred directly on a magnetic tape

Branching habit and the allocation of reproductive resources in conifers.

Science.gov (United States)

Leslie, Andrew B

2012-09-01

Correlated relationships between branch thickness, branch density, and twig and leaf size have been used extensively to study the evolution of plant canopy architecture, but fewer studies have explored the impact of these relationships on the allocation of reproductive resources. This study quantifies pollen cone production in conifers, which have similar basic reproductive biology but vary dramatically in branching habit, in order to test how differences in branch diameter influence pollen cone size and the density with which they are deployed in the canopy. Measurements of canopy branch density, the number of cones per branch and cone size were used to estimate the amount of pollen cone tissues produced by 16 species in three major conifer clades. The number of pollen grains produced was also estimated using direct counts from individual pollen cones. The total amount of pollen cone tissues in the conifer canopy varied little among species and clades, although vegetative traits such as branch thickness, branch density and pollen cone size varied over several orders of magnitude. However, branching habit controls the way these tissues are deployed: taxa with small branches produce small pollen cones at a high density, while taxa with large branches produce large cones relatively sparsely. Conifers appear to invest similar amounts of energy in pollen production independent of branching habit. However, similar associations between branch thickness, branch density and pollen cone size are seen across conifers, including members of living and extinct groups not directly studied here. This suggests that reproductive features relating to pollen cone size are in large part a function of the evolution of vegetative morphology and branching habit.

GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome branching through gibberellic acid signaling in Arabidopsis.

Science.gov (United States)

An, Lijun; Zhou, Zhongjing; Su, Sha; Yan, An; Gan, Yinbo

2012-02-01

Cell differentiation generally corresponds to the cell cycle, typically forming a non-dividing cell with a unique differentiated morphology, and Arabidopsis trichome is an excellent model system to study all aspects of cell differentiation. Although gibberellic acid is reported to be involved in trichome branching in Arabidopsis, the mechanism for such signaling is unclear. Here, we demonstrated that GLABROUS INFLORESCENCE STEMS (GIS) is required for the control of trichome branching through gibberellic acid signaling. The phenotypes of a loss-of-function gis mutant and an overexpressor showed that GIS acted as a repressor to control trichome branching. Our results also show that GIS is not required for cell endoreduplication, and our molecular and genetic study results have shown that GIS functions downstream of the key regulator of trichome branching, STICHEL (STI), to control trichome branching through the endoreduplication-independent pathway. Furthermore, our results also suggest that GIS controls trichome branching in Arabidopsis through two different pathways and acts either upstream or downstream of the negative regulator of gibbellic acid signaling SPINDLY (SPY).

Modeling, Control, and Estimation of Flexible, Aerodynamic Structures

Science.gov (United States)

Ray, Cody W.

Engineers have long been inspired by nature’s flyers. Such animals navigate complex environments gracefully and efficiently by using a variety of evolutionary adaptations for high-performance flight. Biologists have discovered a variety of sensory adaptations that provide flow state feedback and allow flying animals to feel their way through flight. A specialized skeletal wing structure and plethora of robust, adaptable sensory systems together allow nature’s flyers to adapt to myriad flight conditions and regimes. In this work, motivated by biology and the successes of bio-inspired, engineered aerial vehicles, linear quadratic control of a flexible, morphing wing design is investigated, helping to pave the way for truly autonomous, mission-adaptive craft. The proposed control algorithm is demonstrated to morph a wing into desired positions. Furthermore, motivated specifically by the sensory adaptations organisms possess, this work transitions to an investigation of aircraft wing load identification using structural response as measured by distributed sensors. A novel, recursive estimation algorithm is utilized to recursively solve the inverse problem of load identification, providing both wing structural and aerodynamic states for use in a feedback control, mission-adaptive framework. The recursive load identification algorithm is demonstrated to provide accurate load estimate in both simulation and experiment.

A DHHC-type zinc finger protein gene regulates shoot branching in ...

African Journals Online (AJOL)

hope&shola

Arabidopsis. Key words: Arabidopsis, DHHC-type zinc finger protein, At5g04270, shoot branching. ..... and human HIP14 (Ducker et al., 2004), were isolated and identified to .... the control of branching in the rms1 mutant of pea. Plant Physiol.

Bio-Inspired Flexible Cellular Actuating Systems

Science.gov (United States)

2013-11-21

S. Hong, “Robust adaptive boundary control of a flexible marine riser with vessel dynamics,” Automatica, vol. 47, pp. 722–732, 2011. [22] D. H...conditionally accepted. [6] W. He, S. S. Ge, B. V. E. How, Y. S. Choo, and K. S. Hong, “Robust adaptive boundary control of a flexible marine riser ... flexible robotic actuators, often represented by a distributed parameter system or a partial differential equation. We establish a model-guided

Entanglement branching operator

Science.gov (United States)

Harada, Kenji

2018-01-01

We introduce an entanglement branching operator to split a composite entanglement flow in a tensor network which is a promising theoretical tool for many-body systems. We can optimize an entanglement branching operator by solving a minimization problem based on squeezing operators. The entanglement branching is a new useful operation to manipulate a tensor network. For example, finding a particular entanglement structure by an entanglement branching operator, we can improve a higher-order tensor renormalization group method to catch a proper renormalization flow in a tensor network space. This new method yields a new type of tensor network states. The second example is a many-body decomposition of a tensor by using an entanglement branching operator. We can use it for a perfect disentangling among tensors. Applying a many-body decomposition recursively, we conceptually derive projected entangled pair states from quantum states that satisfy the area law of entanglement entropy.

Medial branch neurotomy in low back pain

International Nuclear Information System (INIS)

Masala, Salvatore; Mammucari, Matteo; Simonetti, Giovanni; Nano, Giovanni; Marcia, Stefano

2012-01-01

This study aimed to assess the effectiveness of pulsed radiofrequency medial branch dorsal ramus neurotomy in patients with facet joint syndrome. From January 2008 to April 2010, 92 patients with facet joint syndrome diagnosed by strict inclusion criteria and controlled diagnostic blocks undergone medial branch neurotomy. We did not exclude patients with failed back surgery syndrome (FBSS). Electrodes (20G) with 5-mm active tip were placed under fluoroscopy guide parallel to medial branch. Patients were followed up by physical examination and by Visual Analog Scale and Oswestry Disability Index at 1, 6, and 12 months. In all cases, pain improvement was statistically significant and so quality of life. Three non-FBSS patients had to undergo a second neurotomy because of non-satisfactory pain decrease. Complications were reported in no case. Medial branch radiofrequency neurotomy has confirmed its well-established effectiveness in pain and quality of life improvement as long as strict inclusion criteria be fulfilled and nerve ablation be accomplished by parallel electrode positioning. This statement can be extended also to FBSS patients. (orig.)

Medial branch neurotomy in low back pain

Energy Technology Data Exchange (ETDEWEB)

Masala, Salvatore; Mammucari, Matteo; Simonetti, Giovanni [Interventional Radiology and Radiotherapy University ' ' Tor Vergata' ' , Department of Diagnostic and Molecular Imaging, Rome (Italy); Nano, Giovanni [Interventional Radiology and Radiotherapy University ' ' Tor Vergata' ' , Department of Diagnostic and Molecular Imaging, Rome (Italy); University ' ' Tor Vergata' ' , Department of Radiology, Rome (Italy); Marcia, Stefano [S. Giovanni di Dio Hospital, Department of Diagnostic and Molecular Imaging, Cagliari (Italy)

2012-07-15

This study aimed to assess the effectiveness of pulsed radiofrequency medial branch dorsal ramus neurotomy in patients with facet joint syndrome. From January 2008 to April 2010, 92 patients with facet joint syndrome diagnosed by strict inclusion criteria and controlled diagnostic blocks undergone medial branch neurotomy. We did not exclude patients with failed back surgery syndrome (FBSS). Electrodes (20G) with 5-mm active tip were placed under fluoroscopy guide parallel to medial branch. Patients were followed up by physical examination and by Visual Analog Scale and Oswestry Disability Index at 1, 6, and 12 months. In all cases, pain improvement was statistically significant and so quality of life. Three non-FBSS patients had to undergo a second neurotomy because of non-satisfactory pain decrease. Complications were reported in no case. Medial branch radiofrequency neurotomy has confirmed its well-established effectiveness in pain and quality of life improvement as long as strict inclusion criteria be fulfilled and nerve ablation be accomplished by parallel electrode positioning. This statement can be extended also to FBSS patients. (orig.)

Conformational diversity of flexible ligand in metal-organic frameworks controlled by size-matching mixed ligands

International Nuclear Information System (INIS)

Hua, Xiu-Ni; Qin, Lan; Yan, Xiao-Zhi; Yu, Lei; Xie, Yi-Xin; Han, Lei

2015-01-01

Hydrothermal reactions of N-auxiliary flexible exo-bidentate ligand 1,3-bis(4-pyridyl)propane (bpp) and carboxylates ligands naphthalene-2,6-dicarboxylic acid (2,6-H_2ndc) or 4,4′-(hydroxymethylene)dibenzoic acid (H_2hmdb), in the presence of cadmium(II) salts have given rise to two novel metal-organic frameworks based on flexible ligands (FL-MOFs), namely, [Cd_2(2,6-ndc)_2(bpp)(DMF)]·2DMF (1) and [Cd_3(hmdb)_3(bpp)]·2DMF·2EtOH (2) (DMF=N,N-Dimethylformamide). Single-crystal X-ray diffraction analyses revealed that compound 1 exhibits a three-dimensional self-penetrating 6-connected framework based on dinuclear cluster second building unit. Compound 2 displays an infinite three-dimensional ‘Lucky Clover’ shape (2,10)-connected network based on the trinuclear cluster and V-shaped organic linkers. The flexible bpp ligand displays different conformations in 1 and 2, which are successfully controlled by size-matching mixed ligands during the self-assembly process. - Graphical abstract: Compound 1 exhibits a 3D self-penetrating 6-connected framework based on dinuclear cluster, and 2 displays an infinite 3D ‘Lucky Clover’ shape (2,10)-connected network based on the trinuclear cluster. The flexible 1,3-bis(4-pyridyl)propane ligand displays different conformations in 1 and 2, which successfully controlled by size-matching mixed ligands during the self-assembly process.

Conformational diversity of flexible ligand in metal-organic frameworks controlled by size-matching mixed ligands

Energy Technology Data Exchange (ETDEWEB)

Hua, Xiu-Ni; Qin, Lan; Yan, Xiao-Zhi; Yu, Lei; Xie, Yi-Xin; Han, Lei, E-mail: hanlei@nbu.edu.cn

2015-12-15

Hydrothermal reactions of N-auxiliary flexible exo-bidentate ligand 1,3-bis(4-pyridyl)propane (bpp) and carboxylates ligands naphthalene-2,6-dicarboxylic acid (2,6-H{sub 2}ndc) or 4,4′-(hydroxymethylene)dibenzoic acid (H{sub 2}hmdb), in the presence of cadmium(II) salts have given rise to two novel metal-organic frameworks based on flexible ligands (FL-MOFs), namely, [Cd{sub 2}(2,6-ndc){sub 2}(bpp)(DMF)]·2DMF (1) and [Cd{sub 3}(hmdb){sub 3}(bpp)]·2DMF·2EtOH (2) (DMF=N,N-Dimethylformamide). Single-crystal X-ray diffraction analyses revealed that compound 1 exhibits a three-dimensional self-penetrating 6-connected framework based on dinuclear cluster second building unit. Compound 2 displays an infinite three-dimensional ‘Lucky Clover’ shape (2,10)-connected network based on the trinuclear cluster and V-shaped organic linkers. The flexible bpp ligand displays different conformations in 1 and 2, which are successfully controlled by size-matching mixed ligands during the self-assembly process. - Graphical abstract: Compound 1 exhibits a 3D self-penetrating 6-connected framework based on dinuclear cluster, and 2 displays an infinite 3D ‘Lucky Clover’ shape (2,10)-connected network based on the trinuclear cluster. The flexible 1,3-bis(4-pyridyl)propane ligand displays different conformations in 1 and 2, which successfully controlled by size-matching mixed ligands during the self-assembly process.

Flexible distributed architecture for semiconductor process control and experimentation

Science.gov (United States)

Gower, Aaron E.; Boning, Duane S.; McIlrath, Michael B.

1997-01-01

Semiconductor fabrication requires an increasingly expensive and integrated set of tightly controlled processes, driving the need for a fabrication facility with fully computerized, networked processing equipment. We describe an integrated, open system architecture enabling distributed experimentation and process control for plasma etching. The system was developed at MIT's Microsystems Technology Laboratories and employs in-situ CCD interferometry based analysis in the sensor-feedback control of an Applied Materials Precision 5000 Plasma Etcher (AME5000). Our system supports accelerated, advanced research involving feedback control algorithms, and includes a distributed interface that utilizes the internet to make these fabrication capabilities available to remote users. The system architecture is both distributed and modular: specific implementation of any one task does not restrict the implementation of another. The low level architectural components include a host controller that communicates with the AME5000 equipment via SECS-II, and a host controller for the acquisition and analysis of the CCD sensor images. A cell controller (CC) manages communications between these equipment and sensor controllers. The CC is also responsible for process control decisions; algorithmic controllers may be integrated locally or via remote communications. Finally, a system server images connections from internet/intranet (web) based clients and uses a direct link with the CC to access the system. Each component communicates via a predefined set of TCP/IP socket based messages. This flexible architecture makes integration easier and more robust, and enables separate software components to run on the same or different computers independent of hardware or software platform.

Flexible CP-ABE Based Access Control on Encrypted Data for Mobile Users in Hybrid Cloud System

Institute of Scientific and Technical Information of China (English)

Wen-Min Li; Xue-Lei Li; Qiao-Yan Wen; Shuo Zhang; Hua Zhang

2017-01-01

In hybrid cloud computing, encrypted data access control can provide a fine-grained access method for orga-nizations to enact policies closer to organizational policies. This paper presents an improved CP-ABE (ciphertext-policy attribute-based encryption) scheme to construct an encrypted data access control solution that is suitable for mobile users in hybrid cloud system. In our improvement, we split the original decryption keys into a control key, a secret key and a set of transformation keys. The private cloud managed by the organization administrator takes charge of updating the transformation keys using the control key. It helps to handle the situation of flexible access management and attribute alteration. Meanwhile, the mobile user's single secret key remains unchanged as well as the ciphertext even if the data user's attribute has been revoked. In addition, we modify the access control list through adding the attributes with corresponding control key and transformation keys so as to manage user privileges depending upon the system version. Finally, the analysis shows that our scheme is secure, flexible and efficient to be applied in mobile hybrid cloud computing.

Remote-controlled flexible pose measurement system and method for a moving target in wind tunnel

Directory of Open Access Journals (Sweden)

Wei LIU

2018-01-01

Full Text Available The measurement of position and attitude parameters for the isolated target from a high-speed aircraft is a great challenge in the field of wind tunnel simulation technology. This paper proposes a remote-controlled flexible pose measurement system in wind tunnel conditions for the separation of a target from an aircraft. The position and attitude parameters of a moving object are obtained by utilizing a single camera with a focal length and camera orientation that can be changed based on different measurement conditions. Using this proposed system and method, both the flexibility and efficiency of the pose measurement system can be enhanced in wind tunnel conditions to meet the measurement requirements of different objects and experiments, which is also useful for the development of an intelligent position and attitude measurement system. The position and the focal length of the camera also can be controlled remotely during measurements to enlarge both the vertical and horizontal measurement range of this system. Experiments are conducted in the laboratory to measure the position and attitude of moving objects with high flexibility and efficiency, and the measurement precision of the measurement system is also verified through experiments.

Synthesis of copper hydroxide branched nanocages and their transformation to copper oxide

KAUST Repository

LaGrow, Alec P.

2014-08-21

Copper oxide nanostructures have been explored in the literature for their great promise in the areas of energy storage and catalysis, which can be controlled based on their shape. Herein we describe the synthesis of complex branched nanocages of copper hydroxide with an alternating stacked morphology. The size of the nanocages\\' core and the length of the branches can be controlled by the temperature and ratio of surfactant used, varying the length from 85 to 232 nm long, and varying the core size from 240 to 19 nm. The nanostructures\\' unique morphology forms by controlling the growth of an initial spherical seed, and the crystallization of the anisotropic arms. The Cu(OH)2 nanostructures can be converted to polycrystalline CuO branched nanocages and Cu2O nanoframes. We show that the branched nanocage morphology of CuO has markedly superior catalytic properties to previous reports with CuO nanomaterials, resulting in a rapid and efficient catalyst for C-S coupling. © 2014 American Chemical Society.

Modeling and control of lateral vibration of an axially translating flexible link

Energy Technology Data Exchange (ETDEWEB)

Shin, Heon Seop; Rhim, Sung Soo [Kyung Hee University, Yongin (Korea, Republic of)

2015-01-15

Manipulators used for the transportation of large panel-shape payloads often adopt long and slender links (or forks) with translational joins to carry the payloads. As the size of the payload increases, the length of the links also increases to hold the payload securely. The increased length of the link inevitably amplifies the effect of the flexure in the link. Intuitively, the translational motion of the link in its longitudinal direction should have no effect on the lateral vibration of the link because of the orthogonality between the direction of the translational motion and the lateral vibration. If, however, the link was flexible and translated horizontally (perpendicular to the gravitational field) the asymmetric deflection of the link caused by gravity would break the orthogonality between the two directions, and the longitudinal motion of the link would excite lateral motion in the link. In this paper, the lateral oscillatory motion of the flexible link in a large-scale solar cell panel handling robot is investigated where the links carry the panel in its longitudinal direction. The Newtonian approach in conjunction with the assumed modes method is used for derivation of the equation of motion for the flexible forks where non-zero control force is applied at the base of the link. The analysis illustrates the effect of longitudinal motion on the lateral vibration and dynamic stiffening effect (variation of the natural frequency) of the link due to the translational velocity. Lateral vibration behavior is simulated using the derived equations of the motion. A robust vibration control scheme, the input shaping filter technique, is implemented on the model and the effectiveness of the scheme is verified numerically.

Modeling and control of lateral vibration of an axially translating flexible link

International Nuclear Information System (INIS)

Shin, Heon Seop; Rhim, Sung Soo

2015-01-01

Manipulators used for the transportation of large panel-shape payloads often adopt long and slender links (or forks) with translational joins to carry the payloads. As the size of the payload increases, the length of the links also increases to hold the payload securely. The increased length of the link inevitably amplifies the effect of the flexure in the link. Intuitively, the translational motion of the link in its longitudinal direction should have no effect on the lateral vibration of the link because of the orthogonality between the direction of the translational motion and the lateral vibration. If, however, the link was flexible and translated horizontally (perpendicular to the gravitational field) the asymmetric deflection of the link caused by gravity would break the orthogonality between the two directions, and the longitudinal motion of the link would excite lateral motion in the link. In this paper, the lateral oscillatory motion of the flexible link in a large-scale solar cell panel handling robot is investigated where the links carry the panel in its longitudinal direction. The Newtonian approach in conjunction with the assumed modes method is used for derivation of the equation of motion for the flexible forks where non-zero control force is applied at the base of the link. The analysis illustrates the effect of longitudinal motion on the lateral vibration and dynamic stiffening effect (variation of the natural frequency) of the link due to the translational velocity. Lateral vibration behavior is simulated using the derived equations of the motion. A robust vibration control scheme, the input shaping filter technique, is implemented on the model and the effectiveness of the scheme is verified numerically.

Colloidal polymers with controlled sequence and branching constructed from magnetic field assembled nanoparticles.

Science.gov (United States)

Bannwarth, Markus B; Utech, Stefanie; Ebert, Sandro; Weitz, David A; Crespy, Daniel; Landfester, Katharina

2015-03-24

The assembly of nanoparticles into polymer-like architectures is challenging and usually requires highly defined colloidal building blocks. Here, we show that the broad size-distribution of a simple dispersion of magnetic nanocolloids can be exploited to obtain various polymer-like architectures. The particles are assembled under an external magnetic field and permanently linked by thermal sintering. The remarkable variety of polymer-analogue architectures that arises from this simple process ranges from statistical and block copolymer-like sequencing to branched chains and networks. This library of architectures can be realized by controlling the sequencing of the particles and the junction points via a size-dependent self-assembly of the single building blocks.

Emotional modulation of control dilemmas: the role of positive affect, reward, and dopamine in cognitive stability and flexibility.

Science.gov (United States)

Goschke, Thomas; Bolte, Annette

2014-09-01

Goal-directed action in changing environments requires a dynamic balance between complementary control modes, which serve antagonistic adaptive functions (e.g., to shield goals from competing responses and distracting information vs. to flexibly switch between goals and behavioral dispositions in response to significant changes). Too rigid goal shielding promotes stability but incurs a cost in terms of perseveration and reduced flexibility, whereas too weak goal shielding promotes flexibility but incurs a cost in terms of increased distractibility. While research on cognitive control has long been conducted relatively independently from the study of emotion and motivation, it is becoming increasingly clear that positive affect and reward play a central role in modulating cognitive control. In particular, evidence from the past decade suggests that positive affect not only influences the contents of cognitive processes, but also modulates the balance between complementary modes of cognitive control. In this article we review studies from the past decade that examined effects of induced positive affect on the balance between cognitive stability and flexibility with a focus on set switching and working memory maintenance and updating. Moreover, we review recent evidence indicating that task-irrelevant positive affect and performance-contingent rewards exert different and sometimes opposite effects on cognitive control modes, suggesting dissociations between emotional and motivational effects of positive affect. Finally, we critically review evidence for the popular hypothesis that effects of positive affect may be mediated by dopaminergic modulations of neural processing in prefrontal and striatal brain circuits, and we refine this "dopamine hypothesis of positive affect" by specifying distinct mechanisms by which dopamine may mediate effects of positive affect and reward on cognitive control. We conclude with a discussion of limitations of current research, point to

Tunable, Flexible, and Efficient Optimization of Control Pulses for Practical Qubits

Science.gov (United States)

Machnes, Shai; Assémat, Elie; Tannor, David; Wilhelm, Frank K.

2018-04-01

Quantum computation places very stringent demands on gate fidelities, and experimental implementations require both the controls and the resultant dynamics to conform to hardware-specific constraints. Superconducting qubits present the additional requirement that pulses must have simple parameterizations, so they can be further calibrated in the experiment, to compensate for uncertainties in system parameters. Other quantum technologies, such as sensing, require extremely high fidelities. We present a novel, conceptually simple and easy-to-implement gradient-based optimal control technique named gradient optimization of analytic controls (GOAT), which satisfies all the above requirements, unlike previous approaches. To demonstrate GOAT's capabilities, with emphasis on flexibility and ease of subsequent calibration, we optimize fast coherence-limited pulses for two leading superconducting qubits architectures—flux-tunable transmons and fixed-frequency transmons with tunable couplers.

Multi-Time Scale Control of Demand Flexibility in Smart Distribution Networks

DEFF Research Database (Denmark)

Bhattarai, Bishnu P.; Myers, Kurt S.; Bak-Jensen, Birgitte

2017-01-01

, and distribution system operator’s perspectives. A hierarchical control architecture (HCA) comprising scheduling, coordinative, and adaptive layers is then designed to realize their coordinative goal. This is realized by integrating multi-time scale controls that work from a day-ahead scheduling up to real-time...... adaptive control. The performance of the developed method is investigated with high EV penetration in a typical residential distribution grid. The simulation results demonstrate that HCA efficiently utilizes demand flexibility stemming from EVs to solve grid unbalancing and congestions with simultaneous...... maximization of economic benefits to the participating actors. This is ensured by enabling EV participation in day-ahead, balancing, and regulation markets. For the given network configuration and pricing structure, HCA ensures the EV owners to get paid up to five times the cost they were paying without...

Flexible nanovectors

International Nuclear Information System (INIS)

Pugno, Nicola M

2008-01-01

In this paper we show that the control of adhesion in highly flexible (a property that could be crucial for smart drug delivery but which is still ignored in the literature) nanovectors can help in smartly targeting and delivering the drug. The existence of and the conditions for activating and controlling a super-adhesive state are addressed. Even if such a state has never been observed in nanovectors, our calculations, as well as observations in spiders and geckos, suggest its existence and feasible control. Control of the competition between the drag and the adhesive force is exploited to improve the targeting ability and a hierarchical model is applied to describe a real vasculature. The high flexibility of the nanovector is used to smartly deliver the drug only during adhesion by nanopumping or, as a limiting case, by the new concept of 'adhesion induced nanovector implosion'; a liquid drop analogy is utilized for the calculations. Fast (pumping) and slow (diffusion) drug deliveries can thus be separately controlled by controlling the size and shape of the nanovector. Multiple stage nanovectors are also briefly discussed, mimicking aerospace vector strategies.

Flexible nanovectors

Science.gov (United States)

Pugno, Nicola M.

2008-11-01

In this paper we show that the control of adhesion in highly flexible (a property that could be crucial for smart drug delivery but which is still ignored in the literature) nanovectors can help in smartly targeting and delivering the drug. The existence of and the conditions for activating and controlling a super-adhesive state are addressed. Even if such a state has never been observed in nanovectors, our calculations, as well as observations in spiders and geckos, suggest its existence and feasible control. Control of the competition between the drag and the adhesive force is exploited to improve the targeting ability and a hierarchical model is applied to describe a real vasculature. The high flexibility of the nanovector is used to smartly deliver the drug only during adhesion by nanopumping or, as a limiting case, by the new concept of 'adhesion induced nanovector implosion'; a liquid drop analogy is utilized for the calculations. Fast (pumping) and slow (diffusion) drug deliveries can thus be separately controlled by controlling the size and shape of the nanovector. Multiple stage nanovectors are also briefly discussed, mimicking aerospace vector strategies.

Branched polynomial covering maps

DEFF Research Database (Denmark)

Hansen, Vagn Lundsgaard

1999-01-01

A Weierstrass polynomial with multiple roots in certain points leads to a branched covering map. With this as the guiding example, we formally define and study the notion of a branched polynomial covering map. We shall prove that many finite covering maps are polynomial outside a discrete branch...... set. Particular studies are made of branched polynomial covering maps arising from Riemann surfaces and from knots in the 3-sphere....

Control of a flexible beam actuated by macro-fiber composite patches: I. Modeling and feedforward trajectory control

International Nuclear Information System (INIS)

Schröck, Johannes; Meurer, Thomas; Kugi, Andreas

2011-01-01

This paper considers a systematic approach for motion planning and feedforward control design for a flexible cantilever actuated by piezoelectric macro-fiber composite (MFC) patches. For accurate feedforward tracking control, special attention has to be paid to the inherent nonlinear hysteresis and creep behavior of these actuators. In order to account for these effects an appropriate compensator is applied which allows us to perform the tracking controller design on the basis of a linear infinite-dimensional model. A detailed analysis of the nonlinear actuator behavior as well as the compensator design and the overall experimental validation is presented in the companion paper (Schröck et al 2011 Smart Mater. Struct. 20 015016). The governing equations of motion of the hysteresis and creep compensated cantilever are determined by means of the extended Hamilton's principle. This allows us to consider the influence of the bonded patch actuators on the mechanical properties of the underlying beam structure in a straightforward manner and results in a model with spatially varying system parameters. For the solution of the motion planning and feedforward control problem a flatness-based methodology is proposed. In a first step, the infinite-dimensional system of the MFC-actuated flexible cantilever is approximated by a finite-dimensional model, where all system variables, i.e. the states, input and output, can be parameterized in terms of a so-called flat output. In a second step, it is shown by numerical simulations that these parameterizations converge with increasing system order of the finite-dimensional model such that the feedforward control input can be directly calculated in order to realize prescribed output trajectories

Flexible position probe assembly

International Nuclear Information System (INIS)

Schmitz, J.J.

1977-01-01

The combination of a plurality of tubular transducer sections and a flexible supporting member extending through the tubular transducer sections forms a flexible elongated probe of a design suitable for monitoring the level of an element, such as a nuclear magnetically permeable control rod or liquid. 3 claims, 23 figures

Design and experimental evaluation of flexible manipulator control algorithms

International Nuclear Information System (INIS)

Kwon, D.S.; Hwang, D.H.; Babcock, S.M.; Kress, R.L.

1995-01-01

Within the Environmental Restoration and Waste Management Program of the US Department of Energy, the remediation of single-shell radioactive waste storage tanks is one of the areas that challenge state-of-the-art equipment and methods. The use of long-reach manipulators is being seriously considered for this task. Because of high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems are expected to use hydraulic actuators and to exhibit significant structural flexibility. The controller has been designed to compensate for the hydraulic actuator dynamics by using a load-compensated velocity feedforward loop and to increase the bandwidth by using an inner pressure feedback loop. Shaping filter techniques have been applied as feedforward controllers to avoid structural vibrations during operation. Various types of shaping filter methods have been investigated. Among them, a new approach, referred to as a ''feedforward simulation filter'' that uses embedded simulation, has been presented

Demand flexibility from residential heat pump

DEFF Research Database (Denmark)

Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

2014-01-01

Demand response (DR) is considered as a potentially effective tool to compensate generation intermittency imposed by renewable sources. Further, DR can instigate to offer optimum asset utilization and to avoid or delay the need for new infrastructure investment. Being a sizable load together...... with high thermal time constant, heat pumps (HP) can offer a great deal of flexibility in the future intelligent grids especially to compensate fluctuating generation. However, the HP flexibility is highly dependent on thermal demand profile, namely hot water and space heating demand. This paper proposes...... price based scheduling followed by a demand dispatch based central control and a local voltage based adaptive control, to realize HP demand flexibility. Two-step control architecture, namely local primary control encompassed by the central coordinative control, is proposed to implement...

Adaptive Finite-Time Control for a Flexible Hypersonic Vehicle with Actuator Fault

Directory of Open Access Journals (Sweden)

Jie Wang

2013-01-01

Full Text Available The problem of robust fault-tolerant tracking control is investigated. Simulation on the longitudinal model of a flexible air-breathing hypersonic vehicle (FAHV with actuator faults and uncertainties is conducted. In order to guarantee that the velocity and altitude track their desired commands in finite time with the partial loss of actuator effectiveness, an adaptive fault-tolerant control strategy is presented based on practical finite-time sliding mode method. The adaptive update laws are used to estimate the upper bound of uncertainties and the minimum value of actuator efficiency factor. Finally, simulation results show that the proposed control strategy is effective in rejecting uncertainties even in the presence of actuator faults.

Considerations of device and operational flexibility in FER

International Nuclear Information System (INIS)

Sugihara, Masayoshi; Miki, Nobuharu; Nishio, Satoshi; Yamada, Masao; Yamamoto, Shin

1988-01-01

Expected physics uncertainties in DT burning plasma of FER, which may not be removed completely at the start of construction or DT operation, are reviewed. Several possible device and operational flexibility scenarios to cope with these uncertainties are considered. They are (1) Plasma size enlargement scenario, (2) Plasma shape flexibility scenario, (3) Heating/Current drive/Control system flexibility scenario, (4) Impurity control system flexibility scenario and (5) Advanced operation scenario. Feasibility of these flexibility scenarios are examined and shown to be practicable. However, careful assessment of the physics data base is necessary at the start of construction and DT operation to proceed to actually implement these flexibilities in FER. (author)

Direct model reference adaptive control with application to flexible robots

Science.gov (United States)

Steinvorth, Rodrigo; Kaufman, Howard; Neat, Gregory W.

1992-01-01

A modification to a direct command generator tracker-based model reference adaptive control (MRAC) system is suggested in this paper. This modification incorporates a feedforward into the reference model's output as well as the plant's output. Its purpose is to eliminate the bounded model following error present in steady state when previous MRAC systems were used. The algorithm was evaluated using the dynamics for a single-link flexible-joint arm. The results of these simulations show a response with zero steady state model following error. These results encourage further use of MRAC for various types of nonlinear plants.

Force-controlled robotic assembly processes of rigid and flexible objects methodologies and applications

CERN Document Server

Ghalyan, Ibrahim Fahad Jasim

2016-01-01

This book provides comprehensive and integrated approaches for rigid and flexible object assembly. It presents comparison studies with the available force-guided robotic processes and covers contact-state modeling, scheme control strategies, and position searching algorithms. Further, it includes experimental validations for different assembly situations, including those for the assembly of industrial parts taken from the automotive industry. .

Improvement in the mechanical properties, proton conductivity, and methanol resistance of highly branched sulfonated poly(arylene ether)/graphene oxide grafted with flexible alkylsulfonated side chains nanocomposite membranes

Science.gov (United States)

Liu, Dong; Peng, Jinhua; Li, Zhuoyao; Liu, Bin; Wang, Lei

2018-02-01

Sulfonated polymer/graphene oxide (GO) nanocomposites exhibit excellent properties as proton exchange membranes. However, few investigations on highly branched sulfonated poly(arylene ether)s (HBSPE)/GO nanocomposites as proton exchange membranes are reported. In order to obtain HBSPE-based nanocomposite membranes with better dispersibility and properties, a novel GO containing flexible alkylsulfonated side chains (SGO) is designed and prepared for the first time in this work. The HBSPE/SGO nanocomposite membranes with excellent dispersibility are successfully prepared. The properties of these membranes, including the mechanical properties, ion-exchange capacity, water uptake, proton conductivity, and methanol resistance, are characterized. The nanocomposite membranes exhibit higher tensile strength (32.67 MPa), higher proton conductivity (0.39 S cm-1 at 80 °C) and lower methanol permeability (4.89 × 10-7 cm2 s-1) than the pristine membrane. The nanocomposite membranes also achieve a higher maximum power density (82.36 mW cm-2) than the pristine membrane (67.85 mW cm-2) in single-cell direct methanol fuel cell (DMFC) tests, demonstrating their considerable potential for applications in DMFCs.

Open-loop position tracking control of a piezoceramic flexible beam using a dynamic hysteresis compensator

International Nuclear Information System (INIS)

Nguyen, Phuong-Bac; Choi, Seung-Bok

2010-01-01

This paper proposes a novel hysteresis compensator to enhance control accuracy in open-loop position tracking control of a piezoceramic flexible beam. The proposed hysteresis compensator consists of two components: a rate-independent hysteresis compensator and a nonlinear filter. The compensator is formulated based on the inverse Preisach model, while the weight coefficients of the filter are identified adaptively using a recursive least square (RLS) algorithm. In this work, two dynamic hysteresis compensators (or rate-independent hysteresis compensators) are developed by adopting two different nonlinear filters: Volterra and bilinear filters. In order to demonstrate the improved control accuracy of the proposed dynamic compensators, a flexible beam associated with the piezoceramic actuator is modeled using the finite element method (FEM) and Euler–Bernoulli beam theory. The beam model is then integrated with the proposed hysteresis model to achieve accurate position tracking control at the tip of the beam. An experimental investigation on the tip position tracking control is undertaken by realizing three different hysteresis compensators: a rate-independent hysteresis compensator, a rate-dependent hysteresis compensator with a Volterra nonlinear filter and a rate-independent hysteresis compensator with a bilinear nonlinear filter. It is shown that the proposed dynamic hysteresis compensators can provide much better tracking control accuracy than conventional rate-independent hysteresis compensators

Can a pilates exercise program be effective on balance, flexibility and muscle endurance? A randomized controlled trial.

Science.gov (United States)

Kibar, Sibel; Yardimci, Fatma Ö; Evcik, Deniz; Ay, Saime; Alhan, Aslıhan; Manço, Miray; Ergin, Emine S

2016-10-01

This randomized controlled study aims to determine the effect of pilates mat exercises on dynamic and static balance, hamstring flexibility, abdominal muscle activity and endurance in healthy adults. Female healthy volunteer university students randomly assigned into two groups. Group 1 followed a pilates program for an hour two times a week. Group 2 continued daily activities as control group. Dynamic and static balance were evaluated by Sport Kinesthetic Ability Trainer (KAT) 4000 device. Hamstring flexibility and abdominal endurance were determined by sit-and-reach test, curl-up test respectively. Pressure biofeedback unit (PBU) was used to measure transversus abdominis and lumbar muscle activity. The physical activity of the participants was followed by International Physical Activity Questionnaire-Short Form. Twenty-three subjects in pilates group and 24 control subjects completed the study. In pilates group, statistical significant improvements were observed in curl-up, sit-and-reach test, PBU scores at sixth week (Ppilates group for sit-and-reach test (P=0.01) and PBU scores (Ppilates training program has been found to have beneficial effect on static balance, flexibility, abdominal muscle endurance, abdominal and lumbar muscle activity. These parameters have no effect on balance.

Programación y Control de Sistemas de Fabricación Flexibles: un Enfoque Holónico

Directory of Open Access Journals (Sweden)

J.A. Araúzo

2015-01-01

Full Text Available Resumen: Los sistemas de fabricación holónicos constituyen un nuevo paradigma de producción. Incluidos dentro de las metodologías distribuidas, proponen nuevos esquemas de gestión de la fabricación que combinan auto-organización, jerarquías dinámicas y relaciones horizontales. Este enfoque es más cercano a la naturaleza de los sistemas de fabricación que las aproximaciones clásicas, centralizadas o estrictamente jerárquicas y permiten modelar los sistemas productivos de forma más realista, facilitando la implementación de sistemas más flexibles, escalables y robustos. En este artículo proponemos un sistema de programación y control para sistemas de fabricación flexibles desarrollado según el paradigma holónico. El sistema se basa en una nueva arquitectura que integra dos niveles de decisión: uno de programación basado en subastas, donde cada holón realiza su propio programa local; y otro de lanzamiento y control, a través del cual se coordinan las actividades de los holones. A diferencia de otros trabajos, donde los programas locales son integrados en un programa global que centraliza el sistema, en el sistema propuesto no ocurre así. Es el mecanismo de lanzamiento y control el que integra los programas locales. Además, el prototipo desarrollado puede funcionar con diferentes grados de descentralización, lo que permite valorar las ventajas que proporciona nuestra aproximación mediante simulación. Abstract: Holonic Manufacturing Systems are a new manufacturing paradigm. They are included into distributed methodologies and propose new manufacturing management schemes that combine self-organization, dynamic hierarchies and horizontal relationships. This approach is closer to manufacturing system nature than centralized or strictly traditional hierarchical approaches. It allows modeling manufacturing systems in a more realistic way. So, it make easier to implement more flexible, scalable, responsiveness, reconfigurable

Finite-size scaling of survival probability in branching processes.

Science.gov (United States)

Garcia-Millan, Rosalba; Font-Clos, Francesc; Corral, Álvaro

2015-04-01

Branching processes pervade many models in statistical physics. We investigate the survival probability of a Galton-Watson branching process after a finite number of generations. We derive analytically the existence of finite-size scaling for the survival probability as a function of the control parameter and the maximum number of generations, obtaining the critical exponents as well as the exact scaling function, which is G(y)=2ye(y)/(e(y)-1), with y the rescaled distance to the critical point. Our findings are valid for any branching process of the Galton-Watson type, independently of the distribution of the number of offspring, provided its variance is finite. This proves the universal behavior of the finite-size effects in branching processes, including the universality of the metric factors. The direct relation to mean-field percolation is also discussed.

Multi-flexible-body analysis for application to wind turbine control design

Science.gov (United States)

Lee, Donghoon

The objective of the present research is to build a theoretical and computational framework for the aeroelastic analysis of flexible rotating systems, more specifically with special application to a wind turbine control design. The methodology is based on the integration of Kane's approach for the analysis of the multi-rigid-body subsystem and a mixed finite element method for the analysis of the flexible-body subsystem. The combined analysis is then strongly coupled with an aerodynamic model based on Blade Element Momentum theory for inflow model. The unified framework from the analysis of subsystems is represented as, in a symbolic manner, a set of nonlinear ordinary differential equations with time-variant, periodic coefficients, which describe the aeroelastic behavior of whole system. The framework can be directly applied to control design due to its symbolic characteristics. The solution procedures for the equations are presented for the study of nonlinear simulation, periodic steady-state solution, and Floquet stability of the linearized system about the steady-state solution. Finally the linear periodic system equation can be obtained with both system and control matrices as explicit functions of time, which can be directly applicable to control design. The structural model is validated by comparison of its results with those from software, some of which is commercial. The stability of the linearized system about periodic steady-state solution is different from that obtained about a constant steady-state solution, which have been conventional in the field of wind turbine dynamics. Parametric studies are performed on a wind turbine model with various pitch angles, precone angles, and rotor speeds. Combined with composite material, their effects on wind turbine aeroelastic stability are investigated. Finally it is suggested that the aeroelastic stability analysis and control design for the whole system is crucial for the design of wind turbines, and the

A Flexible Job Shop Scheduling Problem with Controllable Processing Times to Optimize Total Cost of Delay and Processing

Directory of Open Access Journals (Sweden)

Hadi Mokhtari

2015-11-01

Full Text Available In this paper, the flexible job shop scheduling problem with machine flexibility and controllable process times is studied. The main idea is that the processing times of operations may be controlled by consumptions of additional resources. The purpose of this paper to find the best trade-off between processing cost and delay cost in order to minimize the total costs. The proposed model, flexible job shop scheduling with controllable processing times (FJCPT, is formulated as an integer non-linear programming (INLP model and then it is converted into an integer linear programming (ILP model. Due to NP-hardness of FJCPT, conventional analytic optimization methods are not efficient. Hence, in order to solve the problem, a Scatter Search (SS, as an efficient metaheuristic method, is developed. To show the effectiveness of the proposed method, numerical experiments are conducted. The efficiency of the proposed algorithm is compared with that of a genetic algorithm (GA available in the literature for solving FJSP problem. The results showed that the proposed SS provide better solutions than the existing GA.

Participation of Flexible Loads in Load Frequency Control to Support High Wind Penetration

DEFF Research Database (Denmark)

Uslu, Umur; Zhang, Boyang; Pillai, Jayakrishnan Radhakrishna

2016-01-01

The increasing amount of fluctuating wind power penetration in power systems presents many challenges to its operation and control. The new wind power plants are replacing many of the conventional large power plants that ensure power balancing and ancillary services for stable and reliable...... operation of the grid. Therefore, new solutions for power balancing reserves have to be explored and utilized by the grid utilities. To meet these challenges, large sizable loads like alkaline electrolysers, heat pumps and electric vehicles which are gaining popularity can provide system support to the grid...... through their inherent flexibility and energy storage characteristics. This paper investigates the possibilities and potential of such flexible loads to participate in power system frequency regulation in a wind dominated power system. The results show that these consumption units provide better...

Neuro-Oncology Branch

Science.gov (United States)

... BTTC are experts in their respective fields. Neuro-Oncology Clinical Fellowship This is a joint program with ... can increase survival rates. Learn more... The Neuro-Oncology Branch welcomes Dr. Mark Gilbert as new Branch ...

H{sub 2}/H{infinity} control of flexible structures through linear matrix inequalities with pole placement

Energy Technology Data Exchange (ETDEWEB)

Lopes, Jean C. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

2009-07-01

The objective of this work is to apply the H2/H{infinity} control technique using linear matrix inequalities and pole placement constraints to the flexible structures control problem. The H2/H{infinity}control is a technique to design a controller with mixed features of the H2 and H{infinity} control formulations, such as, optimal dynamical performance and robust performance. The Linear Matrix Inequalities allow formulating the problem as a convex optimization problem, and additional constraints can be included such as the pole placement. The pole placement requirement comes from the necessity of adjusting the transient response of the plant and ensuring a specific behavior in terms of speed and damping responses. The mathematical model used for this study is related to a flexible beam, with an applied disturbance and an actuator in different positions. The state-space matrices of the structure were obtained using the finite element method with the Euler-Bernoulli formulation of beams. The results showed that the pole placement constraints can improve the performance of the controller H2/H{infinity}. The Matlab was used for the computational implementation. (author)

BranchAnalysis2D/3D automates morphometry analyses of branching structures.

Science.gov (United States)

Srinivasan, Aditya; Muñoz-Estrada, Jesús; Bourgeois, Justin R; Nalwalk, Julia W; Pumiglia, Kevin M; Sheen, Volney L; Ferland, Russell J

2018-01-15

Morphometric analyses of biological features have become increasingly common in recent years with such analyses being subject to a large degree of observer bias, variability, and time consumption. While commercial software packages exist to perform these analyses, they are expensive, require extensive user training, and are usually dependent on the observer tracing the morphology. To address these issues, we have developed a broadly applicable, no-cost ImageJ plugin we call 'BranchAnalysis2D/3D', to perform morphometric analyses of structures with branching morphologies, such as neuronal dendritic spines, vascular morphology, and primary cilia. Our BranchAnalysis2D/3D algorithm allows for rapid quantification of the length and thickness of branching morphologies, independent of user tracing, in both 2D and 3D data sets. We validated the performance of BranchAnalysis2D/3D against pre-existing software packages using trained human observers and images from brain and retina. We found that the BranchAnalysis2D/3D algorithm outputs results similar to available software (i.e., Metamorph, AngioTool, Neurolucida), while allowing faster analysis times and unbiased quantification. BranchAnalysis2D/3D allows inexperienced observers to output results like a trained observer but more efficiently, thereby increasing the consistency, speed, and reliability of morphometric analyses. Copyright © 2017 Elsevier B.V. All rights reserved.

Bundle Branch Block

Science.gov (United States)

... known cause. Causes can include: Left bundle branch block Heart attacks (myocardial infarction) Thickened, stiffened or weakened ... myocarditis) High blood pressure (hypertension) Right bundle branch block A heart abnormality that's present at birth (congenital) — ...

Pulse-train control of branching processes: Elimination of background and intruder state population

International Nuclear Information System (INIS)

Seidl, Markus; Uiberacker, Christoph; Jakubetz, Werner; Etinski, Mihajlo

2008-01-01

The authors introduce and describe pulse train control (PTC) of population branching in strongly coupled processes as a novel control tool for the separation of competing multiphoton processes. Control strategies are presented based on the different responses of processes with different photonicities and/or different frequency detunings to the pulse-to-pulse time delay and the pulse-to-pulse phase shift in pulse trains. The control efficiency is further enhanced by the property of pulse trains that complete population transfer can be obtained over an extended frequency range that replaces the resonance frequency of simple pulses. The possibility to freely tune the frequency assists the separation of the competing processes and reduces the number of subpulses required for full control. As a sample application, PTC of leaking multiphoton resonances is demonstrated by numerical simulations. In model systems exhibiting sizable background (intruder) state population if excited with single pulses, PTC leading to complete accumulation of population in the target state and elimination of background population is readily achieved. The analysis of the results reveals different mechanisms of control and provides clues on the mechanisms of the leaking process itself. In an alternative setup, pulse trains can be used as a phase-sensitive tool for level switching. By changing only the pulse-to-pulse phase shift of a train with otherwise unchanged parameters, population can be transferred to any of two different target states in a near-quantitative manner.

Hybrid adaptive ascent flight control for a flexible launch vehicle

Science.gov (United States)

Lefevre, Brian D.

hybrid adaptive flight controller, development of a Newton's method based online parameter update that is modified to include a step size which regulates the rate of change in the parameter estimates, comparison of the modified Newton's method and recursive least squares online parameter update algorithms, modification of the neural network's input structure to accommodate for the nature of the nonlinearities present in a launch vehicle's ascent flight, examination of both tracking error based and modeling error based neural network weight update laws, and integration of feedback filters for the purpose of preventing harmful interaction between the flight control system and flexible structural modes. To validate the hybrid adaptive controller, a high-fidelity Ares I ascent flight simulator and a classical gain-scheduled proportional-integral-derivative (PID) ascent flight controller were obtained from the NASA Marshall Space Flight Center. The classical PID flight controller is used as a benchmark when analyzing the performance of the hybrid adaptive flight controller. Simulations are conducted which model both nominal and off-nominal flight conditions with structural flexibility of the vehicle either enabled or disabled. First, rigid body ascent simulations are performed with the hybrid adaptive controller under nominal flight conditions for the purpose of selecting the update laws which drive the indirect and direct adaptive components. With the neural network disabled, the results revealed that the recursive least squares online parameter update caused high frequency oscillations to appear in the engine gimbal commands. This is highly undesirable for long and slender launch vehicles, such as the Ares I, because such oscillation of the rocket nozzle could excite unstable structural flex modes. In contrast, the modified Newton's method online parameter update produced smooth control signals and was thus selected for use in the hybrid adaptive launch vehicle flight

Poisson branching point processes

International Nuclear Information System (INIS)

Matsuo, K.; Teich, M.C.; Saleh, B.E.A.

1984-01-01

We investigate the statistical properties of a special branching point process. The initial process is assumed to be a homogeneous Poisson point process (HPP). The initiating events at each branching stage are carried forward to the following stage. In addition, each initiating event independently contributes a nonstationary Poisson point process (whose rate is a specified function) located at that point. The additional contributions from all points of a given stage constitute a doubly stochastic Poisson point process (DSPP) whose rate is a filtered version of the initiating point process at that stage. The process studied is a generalization of a Poisson branching process in which random time delays are permitted in the generation of events. Particular attention is given to the limit in which the number of branching stages is infinite while the average number of added events per event of the previous stage is infinitesimal. In the special case when the branching is instantaneous this limit of continuous branching corresponds to the well-known Yule--Furry process with an initial Poisson population. The Poisson branching point process provides a useful description for many problems in various scientific disciplines, such as the behavior of electron multipliers, neutron chain reactions, and cosmic ray showers

Shape-controlled synthesis of NIR absorbing branched gold nanoparticles and morphology stabilization with alkanethiols

International Nuclear Information System (INIS)

Van de Broek, B; Frederix, F; Bonroy, K; Jans, H; Jans, K; Borghs, G; Maes, G

2011-01-01

Gold nanoparticles are ideal candidates for clinical applications if their plasmon absorption band is situated in the near infrared region (NIR) of the electromagnetic spectrum. Various parameters, including the nanoparticle shape, strongly influence the position of this absorption band. The aim of this study is to produce stabilized NIR absorbing branched gold nanoparticles with potential for biomedical applications. Hereto, the synthesis procedure for branched gold nanoparticles is optimized varying the different synthesis parameters. By subsequent electroless gold plating the plasmon absorption band is shifted to 747.2 nm. The intrinsic unstable nature of the nanoparticles' morphology can be clearly observed by a spectral shift and limits their use in real applications. However, in this article we show how the stabilization of the branched structure can be successfully achieved by exchanging the initial capping agent for different alkanethiols and disulfides. Furthermore, when using alkanethiols/disulfides with poly(ethylene oxide) units incorporated, an increased stability of the gold nanoparticles is achieved in high salt concentrations up to 1 M and in a cell culture medium. These achievements open a plethora of opportunities for these stabilized branched gold nanoparticles in nanomedicine.

Reversibly Bistable Flexible Electronics

KAUST Repository

Alfaraj, Nasir

2015-05-01

Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

Towards an integration of process planning and production planning and control for flexible manufacturing systems

NARCIS (Netherlands)

Gaalman, GJC; Slomp, J; Suresh, NC

This introduction article attempts to present some major issues relating to the integration of process planning and production planning and control (PPC) for flexible manufacturing systems (FMSs). It shows that the performance of an FMS can be significantly improved and FMS capabilities more

Stochastic control and real options valuation of thermal storage-enabled demand response from flexible district energy systems

OpenAIRE

Kitapbayev, Yerkin; Moriarty, John; Mancarella, Pierluigi

2014-01-01

In district energy systems powered by Combined Heat and Power (CHP) plants, thermal storage can significantly increase CHP flexibility to respond to real time market signals and therefore improve the business case of such demand response schemes in a Smart Grid environment. However, main challenges remain as to what is the optimal way to control inter-temporal storage operation in the presence of uncertain market prices, and then how to value the investment into storage as flexibility enabler...

Does Enhancing Work-Time Control and Flexibility Reduce Turnover? A Naturally Occurring Experiment.

Science.gov (United States)

Moen, Phyllis; Kelly, Erin L; Hill, Rachelle

2011-02-01

We investigate the turnover effects of an organizational innovation (ROWE-Results Only Work Environment) aimed at moving away from standard time practices to focus on results rather than time spent at work. To model rates of turnover, we draw on survey data from a sample of employees at a corporate headquarters (N = 775) and institutional records of turnover over eight months following the ROWE implementation. We find the odds of turnover are indeed lower for employees participating in the ROWE initiative, which offers employees greater work-time control and flexibility, and that this is the case regardless of employees' gender, age, or family life stage. ROWE also moderates the turnover effects of organizational tenure and negative home-to-work spillover, physical symptoms, and job insecurity, with those in ROWE who report these situations generally less likely to leave the organization. Additionally, ROWE reduces turnover intentions among those remaining with the corporation. This research moves the "opting-out" argument from one of private troubles to an issue of greater employee work-time control and flexibility by showing that an organizational policy initiative can reduce turnover.

Branches of the landscape

International Nuclear Information System (INIS)

Dine, Michael; O'Neil, Deva; Sun Zheng

2005-01-01

With respect to the question of supersymmetry breaking, there are three branches of the flux landscape. On one of these, if one requires small cosmological constant, supersymmetry breaking is predominantly at the fundamental scale; on another, the distribution is roughly flat on a logarithmic scale; on the third, the preponderance of vacua are at very low scale. A priori, as we will explain, one can say little about the first branch. The vast majority of these states are not accessible even to crude, approximate analysis. On the other two branches one can hope to do better. But as a result of the lack of access to branch one, and our poor understanding of cosmology, we can at best conjecture about whether string theory predicts low energy supersymmetry or not. If we hypothesize that are on branch two or three, distinctive predictions may be possible. We comment of the status of naturalness within the landscape, deriving, for example, the statistics of the first branch from simple effective field theory reasoning

Control of trichome branching by Chromatin Assembly Factor-1

Directory of Open Access Journals (Sweden)

Hennig Lars

2008-05-01

Full Text Available Abstract Background Chromatin dynamics and stability are both required to control normal development of multicellular organisms. Chromatin assembly factor CAF-1 is a histone chaperone that facilitates chromatin formation and the maintenance of specific chromatin states. In plants and animals CAF-1 is essential for normal development, but it is poorly understood which developmental pathways require CAF-1 function. Results Mutations in all three CAF-1 subunits affect Arabidopsis trichome morphology and lack of CAF-1 function results in formation of trichomes with supernumerary branches. This phenotype can be partially alleviated by external sucrose. In contrast, other aspects of the CAF-1 mutant phenotype, such as defective meristem function and organ formation, are aggravated by external sucrose. Double mutant analyses revealed epistatic interactions between CAF-1 mutants and stichel, but non-epistatic interactions between CAF-1 mutants and glabra3 and kaktus. In addition, mutations in CAF-1 could partly suppress the strong overbranching and polyploidization phenotype of kaktus mutants. Conclusion CAF-1 is required for cell differentiation and regulates trichome development together with STICHEL in an endoreduplication-independent pathway. This function of CAF-1 can be partially substituted by application of exogenous sucrose. Finally, CAF-1 is also needed for the high degree of endoreduplication in kaktus mutants and thus for the realization of kaktus' extreme overbranching phenotype.

Study on color identification for monitoring and controlling fermentation process of branched chain amino acid

Science.gov (United States)

Ma, Lei; Wang, Yizhong; Chen, Ning; Liu, Tiegen; Xu, Qingyang; Kong, Fanzhi

2008-12-01

In this paper, a new method for monitoring and controlling fermentation process of branched chain amino acid (BCAA) was proposed based on color identification. The color image of fermentation broth of BCAA was firstly taken by a CCD camera. Then, it was changed from RGB color model to HIS color model. Its histograms of hue H and saturation S were calculated, which were used as the input of a designed BP network. The output of the BP network was the description of the color of fermentation broth of BCAA. After training, the color of fermentation broth was identified by the BP network according to the histograms of H and S of a fermentation broth image. Along with other parameters, the fermentation process of BCAA was monitored and controlled to start the stationary phase of fermentation soon. Experiments were conducted with satisfied results to show the feasibility and usefulness of color identification of fermentation broth in fermentation process control of BCAA.

Gust load alleviation wind tunnel tests of a large-aspect-ratio flexible wing with piezoelectric control

Directory of Open Access Journals (Sweden)

Ying Bi

2017-02-01

Full Text Available An active control technique utilizing piezoelectric actuators to alleviate gust-response loads of a large-aspect-ratio flexible wing is investigated. Piezoelectric materials have been extensively used for active vibration control of engineering structures. In this paper, piezoelectric materials further attempt to suppress the vibration of the aeroelastic wing caused by gust. The motion equation of the flexible wing with piezoelectric patches is obtained by Hamilton’s principle with the modal approach, and then numerical gust responses are analyzed, based on which a gust load alleviation (GLA control system is proposed. The gust load alleviation system employs classic proportional-integral-derivative (PID controllers which treat piezoelectric patches as control actuators and acceleration as the feedback signal. By a numerical method, the control mechanism that piezoelectric actuators can be used to alleviate gust-response loads is also analyzed qualitatively. Furthermore, through low-speed wind tunnel tests, the effectiveness of the gust load alleviation active control technology is validated. The test results agree well with the numerical results. Test results show that at a certain frequency range, the control scheme can effectively alleviate the z and x wingtip accelerations and the root bending moment of the wing to a certain extent. The control system gives satisfying gust load alleviation efficacy with the reduction rate being generally over 20%.

Review of ASME code criteria for control of primary loads on nuclear piping system branch connections and recommendations for additional development work

International Nuclear Information System (INIS)

Rodabaugh, E.C.; Gwaltney, R.C.; Moore, S.E.

1993-11-01

This report collects and uses available data to reexamine the criteria for controlling primary loads in nuclear piping branch connections as expressed in Section III of the ASME Boiler and Pressure Vessel Code. In particular, the primary load stress indices given in NB-3650 and NB-3683 are reexamined. The report concludes that the present usage of the stress indices in the criteria equations should be continued. However, the complex treatment of combined branch and run moments is not supported by available information. Therefore, it is recommended that this combined loading evaluation procedure be replaced for primary loads by the separate leg evaluation procedure specified in NC/ND-3653.3(c) and NC/ND-3653.3(d). No recommendation is made for fatigue or secondary load evaluations for Class 1 piping. Further work should be done on the development of better criteria for treatment of combined branch and run moment effects

Flexible Mode Control of Grid Connected Wind Energy Conversion System Using Wavelet

OpenAIRE

Jain, Bhavna; Singh, Sameer; Jain, Shailendra; Nema, R. K.

2015-01-01

Small wind turbine systems offer services to critical loads during grid faults and also connected back to grid in normal condition. The connection of a wind energy conversion system to the grid requires a robust phase locked loop (PLL) and continuous monitoring of the grid conditions such as overvoltage, undervoltage, overfrequency, underfrequency, and grid outages. This paper describes a flexible control operation to operate a small wind turbine in both stand-alone mode via planned islanding...

Short-term effects of customized arch support insoles on symptomatic flexible flatfoot in children: A randomized controlled trial.

Science.gov (United States)

Hsieh, Ru-Lan; Peng, Hui-Ling; Lee, Wen-Chung

2018-05-01

Limited evidence is available regarding the effects of insoles on pediatric flexible flatfoot because of the heterogeneity and low methodological quality of previous studies. The purpose of this prospective trial is to examine the short-term effects of customized arch support insoles on symptomatic flexible flatfoot in children by using the International Classification of Functioning, randomized controlled Disability, and Health (ICF) framework. This study was conducted in a rehabilitation outpatient clinic of a teaching hospital. Fifty-two children with symptomatic flexible flatfoot were included. The children in the treatment group wore customized arch support insoles for 12 weeks, whereas those in the control group did not wear the insoles. Both clinical and radiographic measurements, including the navicular drop, foot posture index, Beighton hypermobility score, talonavicular coverage angle, calcaneal inclination angle, and calcaneal-first metatarsal angle, were used for diagnosing flexible flatfoot. Physical activity (10-m normal and fast walking, stair ascent, stair descent, and chair rising), physical function, and psychometric properties (Pediatric Outcome Data Collection Instrument and Pediatric Quality of Life Inventory) were evaluated at the baseline and 12 weeks after the intervention. Compared with the control group, the treatment group exhibited significant improvement in pain/comfort (P = .048), physical health (P = .035), stair ascent time (P = .015), upper extremity and physical function (P = .016), and transfer and basic mobility (P = .042) during the intervention period. Children with flexible flatfoot who wore customized arch support insoles for 12 weeks exhibited significantly improved pain/comfort, physical health, stair ascent time, upper extremity and physical function, and transfer and basic mobility. These variables belong to the domains of body functions and structures and activity and participation in the ICF

Endurance performance and energy metabolism during exercise in mice with a muscle-specific defect in the control of branched-chain amino acid catabolism.

Science.gov (United States)

Xu, Minjun; Kitaura, Yasuyuki; Ishikawa, Takuya; Kadota, Yoshihiro; Terai, Chihaya; Shindo, Daichi; Morioka, Takashi; Ota, Miki; Morishita, Yukako; Ishihara, Kengo; Shimomura, Yoshiharu

2017-01-01

It is known that the catabolism of branched-chain amino acids (BCAAs) in skeletal muscle is suppressed under normal and sedentary conditions but is promoted by exercise. BCAA catabolism in muscle tissues is regulated by the branched-chain α-keto acid (BCKA) dehydrogenase complex, which is inactivated by phosphorylation by BCKA dehydrogenase kinase (BDK). In the present study, we used muscle-specific BDK deficient mice (BDK-mKO mice) to examine the effect of uncontrolled BCAA catabolism on endurance exercise performance and skeletal muscle energy metabolism. Untrained control and BDK-mKO mice showed the same performance; however, the endurance performance enhanced by 2 weeks of running training was somewhat, but significantly less in BDK-mKO mice than in control mice. Skeletal muscle of BDK-mKO mice had low levels of glycogen. Metabolome analysis showed that BCAA catabolism was greatly enhanced in the muscle of BDK-mKO mice and produced branched-chain acyl-carnitine, which induced perturbation of energy metabolism in the muscle. These results suggest that the tight regulation of BCAA catabolism in muscles is important for homeostasis of muscle energy metabolism and, at least in part, for adaptation to exercise training.

Endurance performance and energy metabolism during exercise in mice with a muscle-specific defect in the control of branched-chain amino acid catabolism.

Directory of Open Access Journals (Sweden)

Minjun Xu

Full Text Available It is known that the catabolism of branched-chain amino acids (BCAAs in skeletal muscle is suppressed under normal and sedentary conditions but is promoted by exercise. BCAA catabolism in muscle tissues is regulated by the branched-chain α-keto acid (BCKA dehydrogenase complex, which is inactivated by phosphorylation by BCKA dehydrogenase kinase (BDK. In the present study, we used muscle-specific BDK deficient mice (BDK-mKO mice to examine the effect of uncontrolled BCAA catabolism on endurance exercise performance and skeletal muscle energy metabolism. Untrained control and BDK-mKO mice showed the same performance; however, the endurance performance enhanced by 2 weeks of running training was somewhat, but significantly less in BDK-mKO mice than in control mice. Skeletal muscle of BDK-mKO mice had low levels of glycogen. Metabolome analysis showed that BCAA catabolism was greatly enhanced in the muscle of BDK-mKO mice and produced branched-chain acyl-carnitine, which induced perturbation of energy metabolism in the muscle. These results suggest that the tight regulation of BCAA catabolism in muscles is important for homeostasis of muscle energy metabolism and, at least in part, for adaptation to exercise training.

A Feed-Forward Control Realizing Fast Response for Three-Branch Interleaved DC-DC Converter in DC Microgrid

Directory of Open Access Journals (Sweden)

Haojie Wang

2016-07-01

Full Text Available It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC is proposed for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load changing. A prototype of the TIDC is developed and an experimental platform is built. The experiment results show that DC bus voltage sags or swells caused by load changing can be reduced and the time for voltage recovery can be decreased significantly with the proposed feed-forward control.

A Feed-Forward Control Realizing Fast Response for Three-Branch Interleaved DC-DC Converter in DC Microgrid

DEFF Research Database (Denmark)

Wang, Haojie; Han, Minxiao; Yan, Wenli

2016-01-01

It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC) is proposed...... for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load...... changing. A prototype of the TIDC is developed and an experimental platform is built. The experiment results show that DC bus voltage sags or swells caused by load changing can be reduced and the time for voltage recovery can be decreased significantly with the proposed feed-forward control....

Plexin A3 and turnout regulate motor axonal branch morphogenesis in zebrafish.

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Rajiv Sainath

Full Text Available During embryogenesis motor axons navigate to their target muscles, where individual motor axons develop complex branch morphologies. The mechanisms that control axonal branching morphogenesis have been studied intensively, yet it still remains unclear when branches begin to form or how branch locations are determined. Live cell imaging of individual zebrafish motor axons reveals that the first axonal branches are generated at the ventral extent of the myotome via bifurcation of the growth cone. Subsequent branches are generated by collateral branching restricted to their synaptic target field along the distal portion of the axon. This precisely timed and spatially restricted branching process is disrupted in turnout mutants we identified in a forward genetic screen. Molecular genetic mapping positioned the turnout mutation within a 300 kb region encompassing eight annotated genes, however sequence analysis of all eight open reading frames failed to unambiguously identify the turnout mutation. Chimeric analysis and single cell labeling reveal that turnout function is required cell non-autonomously for intraspinal motor axon guidance and peripheral branch formation. turnout mutant motor axons form the first branch on time via growth cone bifurcation, but unlike wild-type they form collateral branches precociously, when the growth cone is still navigating towards the ventral myotome. These precocious collateral branches emerge along the proximal region of the axon shaft typically devoid of branches, and they develop into stable, permanent branches. Furthermore, we find that null mutants of the guidance receptor plexin A3 display identical motor axon branching defects, and time lapse analysis reveals that precocious branch formation in turnout and plexin A3 mutants is due to increased stability of otherwise short-lived axonal protrusions. Thus, plexin A3 dependent intrinsic and turnout dependent extrinsic mechanisms suppress collateral branch

Stochastic control and real options valuation of thermal storage-enabled demand response from flexible district energy systems

International Nuclear Information System (INIS)

Kitapbayev, Yerkin; Moriarty, John; Mancarella, Pierluigi

2015-01-01

Highlights: • We calculate the real option value of flexibility from CHP-thermal storage. • Stochastic optimal feedback control problem is solved under uncertain market prices. • Efficient real-time numerical solutions combine simulation, regression and recursion. • Clear, interpretable feedback control maps are produced for each hour of the day. • We give a realistic UK case study using projected market gas and electricity prices. - Abstract: In district energy systems powered by Combined Heat and Power (CHP) plants, thermal storage can significantly increase CHP flexibility to respond to real time market signals and therefore improve the business case of such demand response schemes in a Smart Grid environment. However, main challenges remain as to what is the optimal way to control inter-temporal storage operation in the presence of uncertain market prices, and then how to value the investment into storage as flexibility enabler. In this outlook, the aim of this paper is to propose a model for optimal and dynamic control and long term valuation of CHP-thermal storage in the presence of uncertain market prices. The proposed model is formulated as a stochastic control problem and numerically solved through Least Squares Monte Carlo regression analysis, with integrated investment and operational timescale analysis equivalent to real options valuation models encountered in finance. Outputs are represented by clear and interpretable feedback control strategy maps for each hour of the day, thus suitable for real time demand response under uncertainty. Numerical applications to a realistic UK case study with projected market gas and electricity prices exemplify the proposed approach and quantify the robustness of the selected storage solutions

Application of partial differential equation modeling of the control/structural dynamics of flexible spacecraft

Science.gov (United States)

Taylor, Lawrence W., Jr.; Rajiyah, H.

1991-01-01

Partial differential equations for modeling the structural dynamics and control systems of flexible spacecraft are applied here in order to facilitate systems analysis and optimization of these spacecraft. Example applications are given, including the structural dynamics of SCOLE, the Solar Array Flight Experiment, the Mini-MAST truss, and the LACE satellite. The development of related software is briefly addressed.

Guest Editorial: Flexible Operation and Control for Medium Voltage Direct-Current (MVDC) Grid

DEFF Research Database (Denmark)

Li, Yong; Guerrero, Josep M.; Siano, Pierluigi

2017-01-01

We appreciate very much the support from the IET Power Electronics editorial board for this Special Issue on ‘Flexible Operation and Control for Medium Voltage Direct-Current (MVDC) Grid’. In this final version for publication, 15 papers have been selected for this Special Issue. Three papers...... relate to the topology of MVDC converter, four papers relate to the control of MVDC converter, four papers relate to the introduction of application fields of MVDC grid, and four papers relate to the semiconductor power device and drives towards the application in the medium- and high-voltage DC grid....

Electrostatics and Flexibility Drive Membrane Recognition and Early Penetration by Antimicrobial Peptide Dendrimer bH1

Energy Technology Data Exchange (ETDEWEB)

Ravi, Harish Kumar; Stach, Michaela; Soares, Thereza A.; Darbre, Tamis; Reymond, Jean-Louis; Cascella, Michele

2013-08-01

Molecular dynamics simulation of polycationic antimicrobial peptide dendrimer bH1 (Leu)8(DapLeu)4(DapPhe)2DapLys- NH2 binding to membranes suggest that electrostatic 10 interactions with the polyanionic lipopolysaccharide (LPS) and conformational flexibility of the 2,3-diaminopropanoic acid (Dap) branching units drive its selective insertion into microbial membranes.

Optimal reduction of flexible dynamic system

International Nuclear Information System (INIS)

Jankovic, J.

1994-01-01

Dynamic system reduction is basic procedure in various problems of active control synthesis of flexible structures. In this paper is presented direct method for system reduction by explicit extraction of modes included in reduced model form. Criterion for optimal system discrete approximation in synthesis reduced dynamic model is also presented. Subjected method of system decomposition is discussed in relation to the Schur method of solving matrix algebraic Riccati equation as condition for system reduction. By using exposed method procedure of flexible system reduction in addition with corresponding example is presented. Shown procedure is powerful in problems of active control synthesis of flexible system vibrations

Sistemas de controle administrativo no Franchising: aliando controle e flexibilidade estratégica Administrative control systems in Franchising: combining control and strategic flexibility

Directory of Open Access Journals (Sweden)

Maria Lúcia Simas Paulino

2011-03-01

Full Text Available O presente estudo objetivou verificar como o franqueador alia controle e flexibilidade estratégica, identificando os sistemas de controle que utiliza para monitorar, mensurar, avaliar incertezas, validar estratégias, promover mudanças, fazer emergir iniciativas estratégicas e contribuir com o aprendizado da rede, tendo em vista a melhoria contínua da posição competitiva da franquia. O referencial teórico teve como suporte o relacionamento entre franqueador e franqueado proposto na literatura, os custos de transação, a teoria de agência e os sistemas de controle administrativo definidos e categorizados por Simons (1994. Visando o cumprimento do objetivo proposto, utilizou-se a pesquisa do tipo exploratória e a estratégia de estudo de caso único tendo como unidade de análise a área de Marketing e Vendas de uma franqueadora. O instrumento de coleta de dados foi a entrevista semi-estruturada realizada com 4 executivos da área, escolhidos em razão dos temas pesquisados. Através da identificação dos sistemas de controle interativo utilizados pela franqueadora, verificou-se que ela agrega na administração estratégica da franquia, as abordagens gerenciais de minimização de custos e maximização de oportunidades, aliando controle e flexibilidade estratégica.This study aimed to verify how the franchisor combines control and strategic flexibility, identifying control systems it uses to monitor, measure, assess uncertainty, validate strategies, promote change, strategic initiatives to emerge and contribute to the learning network in order continuous improvement of the competitive position of the franchise. The theoretical framework was to support the relationship between franchiser and franchisee proposed in the literature, transaction costs, the agency theory and management control systems defined and categorized by Simons (1994. To fulfill the objective proposed, we used the exploratory research and the strategy of a single

THE FLEXIBILITY-AUTOMATION CORRESPONDENCE TO A VIRTUAL COMMERCIAL SOCIETY

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Liliana Doble

2012-01-01

Full Text Available Design and operation of FMS is based on system requirement can be as productive and flexible as necessary, i.e. obtaining controlled correspondence between the degree of flexibility and automation of system.The flexibility of a FMS (Flexible Manufacturing Systems is determined by two important criteria: Flexible hardware structure of the system; Flexible software structure. Flexible hardware structure of the CS system (calculation system is determined to its turn according to three components: Flexibility of technological subsystem; Flexibility subsystem of storage, transport and handling;Flexibility of informational subsystem.

Towards flexible decision support in thecontrol of animal epidemics

NARCIS (Netherlands)

Ge, L.; Mourits, M.C.M.; Huirne, R.B.M.

2007-01-01

Decision-making in the control of animal epidemics is a dynamic and flexible process. Facing uncertainties about the consequences of control options, flexible decision-making can avoid unnecessary control costs through learning and adjusting. While recognising the importance and complexity of

Direct adaptive fuzzy control of a translating piezoelectric flexible manipulator driven by a pneumatic rodless cylinder

Science.gov (United States)

Qiu, Zhi-cheng; Wang, Bin; Zhang, Xian-min; Han, Jian-da

2013-04-01

This study presents a novel translating piezoelectric flexible manipulator driven by a rodless cylinder. Simultaneous positioning control and vibration suppression of the flexible manipulator is accomplished by using a hybrid driving scheme composed of the pneumatic cylinder and a piezoelectric actuator. Pulse code modulation (PCM) method is utilized for the cylinder. First, the system dynamics model is derived, and its standard multiple input multiple output (MIMO) state-space representation is provided. Second, a composite proportional derivative (PD) control algorithms and a direct adaptive fuzzy control method are designed for the MIMO system. Also, a time delay compensation algorithm, bandstop and low-pass filters are utilized, under consideration of the control hysteresis and the caused high-frequency modal vibration due to the long stroke of the cylinder, gas compression and nonlinear factors of the pneumatic system. The convergence of the closed loop system is analyzed. Finally, experimental apparatus is constructed and experiments are conducted. The effectiveness of the designed controllers and the hybrid driving scheme is verified through simulation and experimental comparison studies. The numerical simulation and experimental results demonstrate that the proposed system scheme of employing the pneumatic drive and piezoelectric actuator can suppress the vibration and achieve the desired positioning location simultaneously. Furthermore, the adopted adaptive fuzzy control algorithms can significantly enhance the control performance.

Involved accounting and control in health care : Different perceptions of management accounting and control systems in the Dutch branch of nursing homes, homes for the elderly and homecare

NARCIS (Netherlands)

Wil van Erp

2014-01-01

The purpose of this study is to explore why and how Management Accounting and Control Systems (MACS) enact and are enacted upon in the Dutch branch of nursing homes, homes for the elderly and home care. In search for answers, this study chooses an actor-network theory (ANT) perspective combined with

Flexible System Integration and Advanced Hierarchical Control Architectures in the Microgrid Research Laboratory of Aalborg University

DEFF Research Database (Denmark)

Meng, Lexuan; Hernández, Adriana Carolina Luna; Diaz, Enrique Rodriguez

2016-01-01

This paper presents the system integration and hierarchical control implementation in an inverter-based microgrid research laboratory (MGRL) in Aalborg University, Denmark. MGRL aims to provide a flexible experimental platform for comprehensive studies of microgrids. The structure of the laborato...

The Direct Effect of Flexible Walls on Fontan Connection Fluid Dynamics

Science.gov (United States)

Tree, Mike; Fagan, Kiley; Yoganathan, Ajit

2014-11-01

The current standard treatment for sufferers of congenital heart defects is the palliative Fontan procedure. The Fontan procedure results in an anastomosis of major veins directly to the branched pulmonary arteries bypassing the dysfunctional ventricle. This total cavopulmonary connection (TCPC) extends life past birth, but Fontan patients still suffer long-term complications like decreased exercise capacity, protein-losing enteropathy, and pulmonary arteriovenous malformations (PAVM). These complications have direct ties to fluid dynamics within the connection. Previous experimental and computation studies of Fontan connection fluid dynamics employed rigid vessel models. More recent studies utilize flexible models, but a direct comparison of the fundamental fluid dynamics between rigid and flexible vessels only exists for a computational model, without a direct experimental validation. Thus, this study was a direct comparison of fluid dynamics within a rigid and two compliant idealized TCPCs. 2D particle image velocimetry measurements were collected at the connection center plane. Results include power loss, hepatic flow distribution, fluid shear stress, and flow structure recognition. The effect of flexible walls on these values and clinical impact will be discussed.

Multi-Objective Flight Control for Drag Minimization and Load Alleviation of High-Aspect Ratio Flexible Wing Aircraft

Science.gov (United States)

Nguyen, Nhan; Ting, Eric; Chaparro, Daniel; Drew, Michael; Swei, Sean

2017-01-01

As aircraft wings become much more flexible due to the use of light-weight composites material, adverse aerodynamics at off-design performance can result from changes in wing shapes due to aeroelastic deflections. Increased drag, hence increased fuel burn, is a potential consequence. Without means for aeroelastic compensation, the benefit of weight reduction from the use of light-weight material could be offset by less optimal aerodynamic performance at off-design flight conditions. Performance Adaptive Aeroelastic Wing (PAAW) technology can potentially address these technical challenges for future flexible wing transports. PAAW technology leverages multi-disciplinary solutions to maximize the aerodynamic performance payoff of future adaptive wing design, while addressing simultaneously operational constraints that can prevent the optimal aerodynamic performance from being realized. These operational constraints include reduced flutter margins, increased airframe responses to gust and maneuver loads, pilot handling qualities, and ride qualities. All of these constraints while seeking the optimal aerodynamic performance present themselves as a multi-objective flight control problem. The paper presents a multi-objective flight control approach based on a drag-cognizant optimal control method. A concept of virtual control, which was previously introduced, is implemented to address the pair-wise flap motion constraints imposed by the elastomer material. This method is shown to be able to satisfy the constraints. Real-time drag minimization control is considered to be an important consideration for PAAW technology. Drag minimization control has many technical challenges such as sensing and control. An initial outline of a real-time drag minimization control has already been developed and will be further investigated in the future. A simulation study of a multi-objective flight control for a flight path angle command with aeroelastic mode suppression and drag

Synthesis and characterization of an exact comb polyisoprene with three branches having the middle branch twice the molecular weight of the other two identical external branches

KAUST Repository

Ratkanthwar, Kedar

2013-01-01

An exact comb polyisoprene (PI) with three branches, with the middle branch having twice the molecular weight of the two other identical external branches, was synthesized by using anionic polymerization high vacuum techniques and appropriate chlorosilane chemistry. The synthetic approach involves (a) the selective replacement of the two chlorines of 4-(dichloromethylsilyl) diphenylethylene (DCMSDPE, key molecule) with identical PI chains by titration with PILi, (b) the addition of sec-BuLi to the double bond of DPE followed by the polymerization of isoprene from the newly created anionic site to form a 3-arm living star PI, (c) the selective replacement of the two chlorines of trichloromethylsilane with 3-arm star PI to form an H-shape intermediate, and (d) the replacement of the remaining chlorine of trichloromethylsilane by linear PI chains with double the molecular weight. All intermediate and final products were characterized via size exclusion chromatography, temperature gradient interaction chromatography and 1H-NMR spectroscopy. As expected, due to the inability to control the exact stoichiometry of the linking reactants, the main product (exact comb PI) is contaminated by a few by-products, despite the fact that anionic polymerization is the most efficient way to produce well-defined polymers. © 2013 The Royal Society of Chemistry.

Experimental analysis of flexibility change with different levels of power reduction by demand response activation on thermostat controlled loads

DEFF Research Database (Denmark)

Lakshmanan, Venkatachalam; Marinelli, Mattia; Hu, Junjie

2017-01-01

This paper studies the flexibility available with thermostatically controlled loads (TCLs) to provide power system services by demand response (DR) activation. Although the DR activation on TCLs can provide power system ancillary services, it is important to know how long such services can...... be provided for when different levels of power reduction are imposed. The flexibility change with different levels of power reduction is tested experimentally with domestic fridges used by real customers with unknown user interaction. The investigation quantifies the flexibility of household fridges...... and the impact of DR activation in terms of deviation in the average temperature. The maximum possible power reduction with the cluster of refrigerators is 67% and the available flexibility with the cluster of refrigerators is 10%. The resulting deviation in the average temperature is 14%....

The use of CAMAC with small computers in the TRIUMF control system

International Nuclear Information System (INIS)

Gurd, D.P.; Heywood, D.R.; Johnson, R.R.

1975-08-01

The TRIUMF control system uses several small computers. This allows tasks to be partitioned in hardware rather than by a complex operating system. This flexibility was especially convenient during the developmental stages of TRIUMF. The multi-mini approach also improves mean time to repair. All control system computers are to be interfaced simultaneously to a single CAMAC system of 35 crates on seven branches. Other computers, belonging to separate systems, communicate with the control system via parallel CAMAC-to-CAMAC links. Modularity at both the computer and controller levels, combined with CAMAC multisourcing, has allowed the introduction of considerable redundancy, thereby increasing overall system reliability. (author)

[Croatian Medical Association--Branch Zagreb].

Science.gov (United States)

Kaić, Zvonimir; Sain, Snjezana; Gulić, Mirjana; Mahovlić, Vjekoslav; Krznarić, Zeljko

2014-01-01

The available literature shows us that "Druztvo ljeciteljah u Zagrebus (the Society of Healers in Zagreb) was founded as far back as the year 1845 by a total of thirteen members. This data allows us to follow the role of doctors and health workers in Zagreb through their everyday profession, research, organizational and social work as well as management through a period of over one hundred to seventy years. The Branch Zagreb was active before the official establishment of subsidiaries of CMA which is evident from the minutes of the regular annual assembly of the Croatian Medical Association on 21 March 1948. Until the end of 1956, there was no clear division of labor, functions and competencies between the Branch and the Main Board. Their actions were instead consolidated and the Branch operated within and under the name of Croatian Medical Association. In that year the Branch became independent. The Branch Zagreb is the largest and one of the most active branches of the Croatian Medical Association. At the moment, the Branch brings together 3621 members, regular members--doctors of medicine (2497), doctors of dental medicine (384), retired physicians (710), and associate members (30 specialists with higher education who are not doctors). The Branch is especially accomplished in its activities in the area of professional development of its members and therefore organizes a series of scientific conferences in the framework of continuous education of physicians, allowing its members to acquire necessary points for the extension of their operating license. The choir "Zagrebacki lijecnici pjevaci" (Zagreb Physicians' Choir) of the Croatian Medical Music Society of the CMA and its activities are inseparable from the Branch Zagreb. The Branch is firmly linked to the parent body, the CMA, and thus has a visible impact on the strategy and the activities of the Association as a whole. Most professional societies of the CMA have their headquarters in Zagreb and this is

Adaptive Robust Sliding Mode Vibration Control of a Flexible Beam Using Piezoceramic Sensor and Actuator: An Experimental Study

Directory of Open Access Journals (Sweden)

Ruo Lin Wang

2014-01-01

Full Text Available This paper presents an experimental study of an adaptive robust sliding mode control scheme based on the Lyapunov’s direct method for active vibration control of a flexible beam using PZT (lead zirconate titanate sensor and actuator. PZT, a type of piezoceramic material, has the advantages of high reliability, high bandwidth, and solid state actuation and is adopted here in forms of surface-bond patches for vibration control. Two adaptive robust sliding mode controllers for vibration suppression are designed: one uses a discontinuous bang-bang robust compensator and the other uses a smooth compensator with a hyperbolic tangent function. Both controllers guarantee asymptotic stability, as proved by the Lyapunov’s direct method. Experimental results verified the effectiveness and the robustness of both adaptive sliding mode controllers. However, from the experimental results, the bang-bang robust compensator causes small-magnitude chattering because of the discontinuous switching actions. With the smooth compensator, vibration is quickly suppressed and no chattering is induced. Furthermore, the robustness of the controllers is successfully demonstrated with ensured effectiveness in vibration control when masses are added to the flexible beam.

Flexible software architecture for user-interface and machine control in laboratory automation.

Science.gov (United States)

Arutunian, E B; Meldrum, D R; Friedman, N A; Moody, S E

1998-10-01

We describe a modular, layered software architecture for automated laboratory instruments. The design consists of a sophisticated user interface, a machine controller and multiple individual hardware subsystems, each interacting through a client-server architecture built entirely on top of open Internet standards. In our implementation, the user-interface components are built as Java applets that are downloaded from a server integrated into the machine controller. The user-interface client can thereby provide laboratory personnel with a familiar environment for experiment design through a standard World Wide Web browser. Data management and security are seamlessly integrated at the machine-controller layer using QNX, a real-time operating system. This layer also controls hardware subsystems through a second client-server interface. This architecture has proven flexible and relatively easy to implement and allows users to operate laboratory automation instruments remotely through an Internet connection. The software architecture was implemented and demonstrated on the Acapella, an automated fluid-sample-processing system that is under development at the University of Washington.

Wavelength Tunable Flip-Flop Operation of a Modulated Grating Y-branch Laser

DEFF Research Database (Denmark)

An, Yi; Lorences Riesgo, Abel; Peucheret, Christophe

2012-01-01

Wavelength tunable flip-flop operation is experimentally demonstrated in a single modulated grating Y-branch laser for the first time. The control pulses have energies of 0.16-0.34 pJ and the switching time is about 200 ps.......Wavelength tunable flip-flop operation is experimentally demonstrated in a single modulated grating Y-branch laser for the first time. The control pulses have energies of 0.16-0.34 pJ and the switching time is about 200 ps....

Cognitive Flexibility in Obsessive Compulsive Disorder

DEFF Research Database (Denmark)

Jónsson, Hjalti; Salkovskis, Paul M.

BT for problems such as OCD requires a level of cognitive flexibility (that is the ability to take a different perspective on ones problems). It could be argued that problems in set shifting (by neuropsychological tests) might underpin problems in this area. Two assessments were used (1: perception...... of cognitive flexibility was assessed by questionnaire 2: neuropsychological evaluation of set shifting). This study will recruit three groups: OCD patients, anxious and healthy controls. Cognitive flexibility is measured using modified version of the Cognitive Flexibility Scale (Martin & Rubin, 1995......) and neuropsychological measures of cognitive flexibility (Wisconsin Cart Sorting Test, Trail Making Test A/B, The Brixton Test). IN addition to the group comparison, the relationship between perceived flexibility, set shifting and psychopathology will be investigated. The implications of the findings for treatment...

Robust Switching Control and Subspace Identification for Flutter of Flexible Wing

Directory of Open Access Journals (Sweden)

Yizhe Wang

2018-01-01

Full Text Available Active flutter suppression and subspace identification for a flexible wing model using micro fiber composite actuator were experimentally studied in a low speed wind tunnel. NACA0006 thin airfoil model was used for the experimental object to verify the performance of identification algorithm and designed controller. The equation of the fluid, vibration, and piezoelectric coupled motion was theoretically analyzed and experimentally identified under the open-loop and closed-loop condition by subspace method for controller design. A robust pole placement algorithm in terms of linear matrix inequality that accommodates the model uncertainty caused by identification deviation and flow speed variation was utilized to stabilize the divergent aeroelastic system. For further enlarging the flutter envelope, additional controllers were designed subject to the models beyond the flutter speed. Wind speed was measured online as the decision parameter of switching between the controllers. To ensure the stability of arbitrary switching, Common Lyapunov function method was applied to design the robust pole placement controllers for different models to ensure that the closed-loop system shared a common Lyapunov function. Wind tunnel result showed that the designed controllers could stabilize the time varying aeroelastic system over a wide range under arbitrary switching.

Controllable preparation of TiO2 nanowire arrays on titanium mesh for flexible dye-sensitized solar cells

International Nuclear Information System (INIS)

Liu, Wenwu; Lu, Hui; Zhang, Mei; Guo, Min

2015-01-01

Graphical abstract: TiO 2 nanowire arrays with controlled morphology and density have been synthesized on Ti mesh substrates by hydrothermal approach for flexible dye-sensitized solar cells which showed well photovoltaic efficiency of 3.42%. - Highlights: • Flexible titanium mesh was first used for hydrothermal preparation of TiO 2 NWAs. • The formation mechanism of the TiO 2 nanostructures was discussed. • The density, average diameter, and morphology of TiO 2 NWAs can be controlled. • The effects of the sensitization temperature and time on the properties were studied. - Abstract: TiO 2 nanowire arrays (NWAs) with an average diameter of 80 nm have been successfully synthesized on titanium (Ti) mesh substrates via hydrothermal method. The effects of preparing conditions such as concentration of NaOH solution, reaction time, and hydrothermal temperature on the growth of TiO 2 nanoarrays and its related photovoltaic properties were systematically investigated by scanning electron microscopy, X-ray diffraction, and photovoltaic properties test. The growth mechanism of the Ti mesh-supported TiO 2 nanostructures was discussed in detail. Moreover, a parametric study was performed to determine the optimized temperature and time of the dye sensitized process for the flexible dye-sensitized solar cell (DSSC). It is demonstrated that hydrothermal parameters had obvious influence on the morphology and growth density of the as-prepared TiO 2 nanoarrays. In addition, the performance of the flexible DSSC depended strongly on the sensitization temperature and time. By utilizing Ti mesh-supported TiO 2 NWAs (with a length of about 14 μm) as a photoanode, the flexible DSSC with a short circuit current density of 10.49 mA cm −2 , an open-circuit voltage of 0.69 V, and an overall power conversion efficiency of 3.42% was achieved

Ampicillin-Ester Bonded Branched Polymers: Characterization, Cyto-, Genotoxicity and Controlled Drug-Release Behaviour

Directory of Open Access Journals (Sweden)

Ewa Oledzka

2014-06-01

Full Text Available The development and characterization of novel macromolecular conjugates of ampicillin using branched biodegradable polymers has been described in this study. The conjugates have been prepared coupling the β-lactam antibiotic with branched polymer matrices based on the natural oligopeptide core. The cyto- and genotoxicity of the synthesized polymers were evaluated with a bacterial luminescence test, two protozoan assays and Salmonella typhimurium TA1535. The presence of a newly formed covalent bond between the drug and the polymer matrices was confirmed by 1H-NMR and FTIR studies. A drug content (15.6 and 10.2 mole % in the macromolecular conjugates has been determined. The obtained macromolecular products have been subjected to further in vitro release studies. The total percentage of ampicillin released after 21 days of incubation was nearly 60% and 14% and this resulted from the different physicochemical properties of the polymeric matrices. This is the first report on the application of branched biodegradable polymeric matrices for the covalent conjugation of ampicillin. The obtained results showed that the synthesized macromolecular drug-conjugates might slowly release the active drug molecule and improve the pharmacokinetics of ampicillin.

High speed CAMAC differential branch highway driver

International Nuclear Information System (INIS)

McMillan, D.E.; Nelson, R.O.; Poore, R.V.; Sunier, J.W.; Ross, J.J.

1979-01-01

A new CAMAC branch driver is described that incorporates several unusual features which combine to give reliable, high-speed performance. These include balanced line driver/receivers, stored CAMAC command lists, 8 DMA channels, pseudo LAMS, hardware priority encoding of LAMS, and hardware-implemented Q-controlled block transfers. 3 figures

Detecting Signatures of Positive Selection along Defined Branches of a Population Tree Using LSD.

Science.gov (United States)

Librado, Pablo; Orlando, Ludovic

2018-06-01

Identifying the genomic basis underlying local adaptation is paramount to evolutionary biology, and bears many applications in the fields of conservation biology, crop, and animal breeding, as well as personalized medicine. Although many approaches have been developed to detect signatures of positive selection within single populations and population pairs, the increasing wealth of high-throughput sequencing data requires improved methods capable of handling multiple, and ideally large number of, populations in a single analysis. In this study, we introduce LSD (levels of exclusively shared differences), a fast and flexible framework to perform genome-wide selection scans, along the internal and external branches of a given population tree. We use forward simulations to demonstrate that LSD can identify branches targeted by positive selection with remarkable sensitivity and specificity. We illustrate a range of potential applications by analyzing data from the 1000 Genomes Project and uncover a list of adaptive candidates accompanying the expansion of anatomically modern humans out of Africa and their spread to Europe.

Attitude and vibration control of a satellite containing flexible solar arrays by using reaction wheels, and piezoelectric transducers as sensors and actuators

Science.gov (United States)

da Fonseca, Ijar M.; Rade, Domingos A.; Goes, Luiz C. S.; de Paula Sales, Thiago

2017-10-01

The primary purpose of this paper is to provide insight into control-structure interaction for satellites comprising flexible appendages and internal moving components. The physical model considered herein aiming to attend such purpose is a rigid-flexible satellite consisting of a rigid platform containing two rotating flexible solar panels. The solar panels rotation is assumed to be in a sun-synchronous configuration mode. The panels contain surface-bonded piezoelectric patches that can be used either as sensors for the elastic displacements or as actuators to counteract the vibration motion. It is assumed that in the normal mode operation the satellite platform points towards the Earth while the solar arrays rotate so as to follow the Sun. The vehicle moves in a low Earth polar orbit. The technique used to obtain the mathematical model combines the Lagrangian formulation with the Finite Elements Method used to describe the dynamics of the solar panel. The gravity-gradient torque as well as the torque due to the interaction of the Earth magnetic field and the satellite internal residual magnetic moment is included as environmental perturbations. The actuators are three reaction wheels for attitude control and piezoelectric actuators to control the flexible motion of the solar arrays. Computer simulations are performed using the MATLAB® software package. The following on-orbit satellite operating configurations are object of analysis: i) Satellite pointing towards the Earth (Earth acquisition maneuver) by considering the initial conditions in the elastic displacement equal to zero, aiming the assessment of the flexible modes excitation by the referred maneuver; ii) the satellite pointing towards the Earth with the assumption of an initial condition different from zero for the flexible motion such that the attitude alterations are checked against the elastic motion disturbance; and iii) attitude acquisition accomplished by taking into account initial conditions

Single-crystalline self-branched anatase titania nanowires for dye-sensitized solar cells

Science.gov (United States)

Li, Zhenquan; Yang, Huang; Wu, Fei; Fu, Jianxun; Wang, Linjun; Yang, Weiguang

2017-03-01

The morphology of the anatase titania plays an important role in improving the photovoltaic performance in dye-sensitized solar cells. In this work, single-crystalline self-branched anatase TiO2 nanowires have been synthesized by hydrothermal method using TBAH and CTAB as morphology controlling agents. The obtained self-branched TiO2 nanowires dominated by a large percentage of (010) facets. The photovoltaic conversion efficiency (6.37%) of dye-sensitized solar cell (DSSC) based on the self-branched TiO2 nanowires shows a significant improvement (26.6%) compared to that of P25 TiO2 (5.03%). The enhanced performance of the self-branched TiO2 nanowires-based DSSC is due to heir large percent of exposed (010) facets which have strong dye adsorption capacity and effective charge transport of the self-branched 1D nanostructures.

Continuous high order sliding mode controller design for a flexible air-breathing hypersonic vehicle.

Science.gov (United States)

Wang, Jie; Zong, Qun; Su, Rui; Tian, Bailing

2014-05-01

This paper investigates the problem of tracking control with uncertainties for a flexible air-breathing hypersonic vehicle (FAHV). In order to overcome the analytical intractability of this model, an Input-Output linearization model is constructed for the purpose of feedback control design. Then, the continuous finite time convergence high order sliding mode controller is designed for the Input-Output linearization model without uncertainties. In addition, a nonlinear disturbance observer is applied to estimate the uncertainties in order to compensate the controller and disturbance suppression, where disturbance observer and controller synthesis design is obtained. Finally, the synthesis of controller and disturbance observer is used to achieve the tracking for the velocity and altitude of the FAHV and simulations are presented to illustrate the effectiveness of the control strategies. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Maxillofacial osseous reconstruction using the angular branch of the thoracodorsal vessels.

LENUS (Irish Health Repository)

Dolderer, Jürgen H

2010-09-01

Mandibular and maxillary resections can produce complex three-dimensional defects requiring skeletal, soft tissue, and epithelial reconstruction. The subscapular vascular axis offers a source of skin, bone, and muscle on a single pedicle for microvascular flap transfer. We reviewed four cases where the subscapular vascular pedicle was used as a source of tissue for complex facial reconstructions in maxillofacial defects. Reconstruction of these complex defects was performed with a latissimus dorsi muscle or myocutaneous flap in combination with the lateral border of the scapula, harvested on the angular branch of the thoracodorsal vessels. There were three cases of maxillectomy and one case of partial mandibulectomy for malignant tumors. In each case, the angular branch of the thoracodorsal artery supplied 6 to 8 cm of the lateral border of the scapula and a latissimus dorsi myocutaneous flap was used for soft tissue reconstruction. Follow-up ranged from 9 months to 3 years and in all cases there was successful bony union. Shoulder movement was normal. This series encourages the further use of subscapular axis flaps as flexible sources of combined myocutaneous and osseous flaps on a single vascular pedicle in cases of complex maxillofacial reconstruction.

Flexible MEMS: A novel technology to fabricate flexible sensors and electronics

Science.gov (United States)

Tu, Hongen

This dissertation presents the design and fabrication techniques used to fabricate flexible MEMS (Micro Electro Mechanical Systems) devices. MEMS devices and CMOS(Complementary Metal-Oxide-Semiconductor) circuits are traditionally fabricated on rigid substrates with inorganic semiconductor materials such as Silicon. However, it is highly desirable that functional elements like sensors, actuators or micro fluidic components to be fabricated on flexible substrates for a wide variety of applications. Due to the fact that flexible substrate is temperature sensitive, typically only low temperature materials, such as polymers, metals, and organic semiconductor materials, can be directly fabricated on flexible substrates. A novel technology based on XeF2(xenon difluoride) isotropic silicon etching and parylene conformal coating, which is able to monolithically incorporate high temperature materials and fluidic channels, was developed at Wayne State University. The technology was first implemented in the development of out-of-plane parylene microneedle arrays that can be individually addressed by integrated flexible micro-channels. These devices enable the delivery of chemicals with controlled temporal and spatial patterns and allow us to study neurotransmitter-based retinal prosthesis. The technology was further explored by adopting the conventional SOI-CMOS processes. High performance and high density CMOS circuits can be first fabricated on SOI wafers, and then be integrated into flexible substrates. Flexible p-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect-Transistors) were successfully integrated and tested. Integration of pressure sensors and flow sensors based on single crystal silicon has also been demonstrated. A novel smart yarn technology that enables the invisible integration of sensors and electronics into fabrics has been developed. The most significant advantage of this technology is its post-MEMS and post-CMOS compatibility. Various high

Spiral branches and star formation

International Nuclear Information System (INIS)

Zasov, A.V.

1974-01-01

Origin of spiral branches of galaxies and formation of stars in them are considered from the point of view of the theory of the gravitational gas condensation, one of comparatively young theories. Arguments are presented in favour of the stellar condensation theory. The concept of the star formation of gas is no longer a speculative hypothesis. This is a theory which assumes quantitative verification and explains qualitatively many facts observed. And still our knowledge on the nature of spiral branches is very poor. It still remains vague what processes give origin to spiral branches, why some galaxies have spirals and others have none. And shapes of spiral branches are diverse. Some cases are known when spiral branches spread outside boundaries of galaxies themselves. Such spirals arise exclusively in the region where there are two or some interacting galaxies. Only first steps have been made in the explanation of the galaxy spiral branches, and it is necessary to carry out new observations and new theoretical calculations

Consumer Central Energy Flexibility in Office Buildings

DEFF Research Database (Denmark)

Billanes, Joy Dalmacio; Ma, Zheng; Jørgensen, Bo Nørregaard

2017-01-01

Energy flexibility in buildings will play an important role in the smart energy system. Office buildings have more potentials to provide energy flexibility to the grid compared to other types of buildings, due to the existing building management, control systems and large energy consumption....... Consumers in office buildings (building owners/managers and occupants) take a main role for adopting and engaging in building energy flexibility. In this paper provides a systematic review of consumer central energy flexibility in office buildings with the discussion of social, technical and business...... can boost energy flexibility in the office buildings....

F2AC: A Lightweight, Fine-Grained, and Flexible Access Control Scheme for File Storage in Mobile Cloud Computing

Directory of Open Access Journals (Sweden)

Wei Ren

2016-01-01

Full Text Available Current file storage service models for cloud servers assume that users either belong to single layer with different privileges or cannot authorize privileges iteratively. Thus, the access control is not fine-grained and flexible. Besides, most access control methods at cloud servers mainly rely on computationally intensive cryptographic algorithms and, especially, may not be able to support highly dynamic ad hoc groups with addition and removal of group members. In this paper, we propose a scheme called F2AC, which is a lightweight, fine-grained, and flexible access control scheme for file storage in mobile cloud computing. F2AC can not only achieve iterative authorization, authentication with tailored policies, and access control for dynamically changing accessing groups, but also provide access privilege transition and revocation. A new access control model called directed tree with linked leaf model is proposed for further implementations in data structures and algorithms. The extensive analysis is given for justifying the soundness and completeness of F2AC.

Characterization of the Diameter, branch angle and longevity of axial branches of Nothofagusobliqua

Directory of Open Access Journals (Sweden)

Patricio Corvalán Vera

2017-08-01

Full Text Available The lack of knowledge about grow dynamics of the living tree crown of Nothofagusobliqua secondary growth forests strongly limits the objective formulation of silvicultural schemes oriented to the industrial production of high quality wood. Therefore, in this work, we described basic relationships between tree size, age and angle branches insertion and the crown. Considering a sample data of 59 dominant trees, distributed in different age conditions, we applied a combined analysis technique of stem analysis, steam taper analysis and thickest branch measurement in each decile of the total height. This approach allowed us to determine that there is a significant relationship between the steam diameter, the angle insertion and the age of the branch, as well as the size and age of the trees. Also, the thicker branches tend to have lower insertion angles, to be older, to be located at lower relative heights and to be located in larger diameter sections. Taking into consideration these relationships, it is possible to build new predicted branch models as tools for the development of silvicultural schemes to suit different log grade.

Branch prediction in the pentium family

DEFF Research Database (Denmark)

Fog, Agner

1998-01-01

How the branch prediction mechanism in the Pentium has been uncovered with all its quirks, and the incredibly more effective branch prediction in the later versions.......How the branch prediction mechanism in the Pentium has been uncovered with all its quirks, and the incredibly more effective branch prediction in the later versions....

Mode Adaptive Droop Control with Virtual Output Impedances for an Inverter-Based Flexible AC Microgrid

DEFF Research Database (Denmark)

Kim, Jaehong; Guerrero, Josep M.; Rodriguez, Pedro

2011-01-01

A decentralized power control method in a singlephase flexible acmicrogrid is proposed in this paper. Droop control is widely considered to be a good choice for managing the power flows between microgrid converters in a decentralized manner. In this work, to enhance the power loop dynamics, droop...... control combined with a derivative controller is used in islanded mode. In grid-connected mode, to strictly control the power factor in the point of common coupling (PCC), a droop method combined with an integral controller is adopted. Small-signal analysis of the proposed control is shown both...... in islanded and grid-connected mode. The proposed control scheme does not need any mode switching action. Thus, it is relatively simple in control for full mode of operation. Smooth transitions between the operation modes and the effectiveness of the proposed control scheme are evaluated through simulation...

Branching processes in biology

CERN Document Server

Kimmel, Marek

2015-01-01

This book provides a theoretical background of branching processes and discusses their biological applications. Branching processes are a well-developed and powerful set of tools in the field of applied probability. The range of applications considered includes molecular biology, cellular biology, human evolution and medicine. The branching processes discussed include Galton-Watson, Markov, Bellman-Harris, Multitype, and General Processes. As an aid to understanding specific examples, two introductory chapters, and two glossaries are included that provide background material in mathematics and in biology. The book will be of interest to scientists who work in quantitative modeling of biological systems, particularly probabilists, mathematical biologists, biostatisticians, cell biologists, molecular biologists, and bioinformaticians. The authors are a mathematician and cell biologist who have collaborated for more than a decade in the field of branching processes in biology for this new edition. This second ex...

Renal Branch Artery Stenosis

DEFF Research Database (Denmark)

Andersson, Zarah; Thisted, Ebbe; Andersen, Ulrik Bjørn

2017-01-01

Renovascular hypertension is a common cause of pediatric hypertension. In the fraction of cases that are unrelated to syndromes such as neurofibromatosis, patients with a solitary stenosis on a branch of the renal artery are common and can be diagnostically challenging. Imaging techniques...... that perform well in the diagnosis of main renal artery stenosis may fall short when it comes to branch artery stenosis. We report 2 cases that illustrate these difficulties and show that a branch artery stenosis may be overlooked even by the gold standard method, renal angiography....

Electronic Control on Linear versus Branched Alkylation of 2-/3-Aroylbenzofurans with Acrylates: Combined DFT and Synthetic Studies.

Science.gov (United States)

Srinivas, Kolluru; Dangat, Yuvraj; Kommagalla, Yadagiri; Vanka, Kumar; Ramana, Chepuri V

2017-06-01

Investigations on the factors that govern unusual branched alkylation of 2-aroylbenzofurans with acrylates by Ru-catalyzed carbonyl-directed C-H activation has been carried out by calculating the kinetics associated with the two key steps-the coordination of the acrylate with the intermediate ruthenacycle and the subsequent migratory insertion reaction-studied with the help of DFT calculations. Eight possible orientations for each mode of alkylation have been considered for the calculations. From these calculations, it has been understood that there is a synergistic operation of the steric and electronic effects favoring the branched alkylation. Further DFT investigations on the alkylation of the isomeric 3-aroylbenzofurans indicated a preference for the linear alkylation and this has been verified experimentally. Overall, the observed/calculated complementary selectivity in the alkylation of 2-/3-aroylbenzofurans with acrylates reveals that the substrate-dependent charge distribution of the Ru-C bond in the intermediate ruthenacycle is an important determining factor and thus the current work opens up a new domain of substrate design for controlling regioselectivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vegetation survey of PEN Branch wetlands

Energy Technology Data Exchange (ETDEWEB)

1991-01-01

A survey was conducted of vegetation along Pen Branch Creek at Savannah River Site (SRS) in support of K-Reactor restart. Plants were identified to species by overstory, understory, shrub, and groundcover strata. Abundance was also characterized and richness and diversity calculated. Based on woody species basal area, the Pen Branch delta was the most impacted, followed by the sections between the reactor and the delta. Species richness for shrub and groundcover strata were also lowest in the delta. No endangered plant species were found. Three upland pine areas were also sampled. In support of K Reactor restart, this report summarizes a study of the wetland vegetation along Pen Branch. Reactor effluent enters Indian Grove Branch and then flows into Pen Branch and the Pen Branch Delta.

Study on control schemes of flexible steering system of a multi-axle all-wheel-steering robot

Directory of Open Access Journals (Sweden)

Pingxia Zhang

2016-05-01

Full Text Available It is well known that a multi-axle wheeled robot possesses larger load capability and also higher drive performance. However, its steering flexibility is degraded due to the large number of wheels. In order to solve this problem, in this article, we proposed three control schemes based on the center of rotation or the steering angles of both the first- and last-axle wheels. To release these control schemes, steering mode selection and also the left wheel’s steering angle in a specific axle are added approaching a practical application. Thereafter, the remaining wheels’ steering angles can be calculated with the Ackerman steering theorem. In order to verify the control effects, a five-axle all-wheel-steering wheeled robot has been developed with the Bluetooth wireless monitor system. Based on the newly designed robot, validation experiments are carried out, such as lateral movement, situ rotation, and multi-mode steering within a narrow space. The results indicate that the proposed design in this article can ensure a more flexible and faster movement within a narrow space. It shows large potential in obstacle avoidance compared with the conventional partial-wheel steering mode.

A flexible dialogue with the computer in the control room of the Saclay's linac

International Nuclear Information System (INIS)

Bianchi, G.; Gourcy, G.; Gournay, J.F.; Jablonka, M.

1976-01-01

In the Control Room of the 600 MeV Electron Linac of Saclay (ALS) the use of a powerful visual display (including its own computer) allows to make very simple and flexible the dialogue of the operators with the main computer. As an example we describe a program permitting to select every number of parameters among 320 in order to assign them to one of the functions of the system. (author)

Highly efficient Cu(In,Ga)Se2 solar cells grown on flexible polymer films.

Science.gov (United States)

Chirilă, Adrian; Buecheler, Stephan; Pianezzi, Fabian; Bloesch, Patrick; Gretener, Christina; Uhl, Alexander R; Fella, Carolin; Kranz, Lukas; Perrenoud, Julian; Seyrling, Sieghard; Verma, Rajneesh; Nishiwaki, Shiro; Romanyuk, Yaroslav E; Bilger, Gerhard; Tiwari, Ayodhya N

2011-09-18

Solar cells based on polycrystalline Cu(In,Ga)Se(2) absorber layers have yielded the highest conversion efficiency among all thin-film technologies, and the use of flexible polymer films as substrates offers several advantages in lowering manufacturing costs. However, given that conversion efficiency is crucial for cost-competitiveness, it is necessary to develop devices on flexible substrates that perform as well as those obtained on rigid substrates. Such comparable performance has not previously been achieved, primarily because polymer films require much lower substrate temperatures during absorber deposition, generally resulting in much lower efficiencies. Here we identify a strong composition gradient in the absorber layer as the main reason for inferior performance and show that, by adjusting it appropriately, very high efficiencies can be obtained. This implies that future manufacturing of highly efficient flexible solar cells could lower the cost of solar electricity and thus become a significant branch of the photovoltaic industry.

Singularity and steering logic for control moment gyros on flexible space structures

Science.gov (United States)

Hu, Quan; Guo, Chuandong; Zhang, Jun

2017-08-01

Control moment gyros (CMGs) are a widely used device for generating control torques for spacecraft attitude control without expending propellant. Because of its effectiveness and cleanness, it has been considered to be mounted on a space structure for active vibration suppression. The resultant system is the so-called gyroelastic body. Since CMGs could exert both torque and modal force to the structure, it can also be used to simultaneously achieve attitude maneuver and vibration reduction of a flexible spacecraft. In this paper, we consider the singularity problem in such application of CMGs. The dynamics of an unconstrained gyroelastic body is established, from which the output equations of the CMGs are extracted. Then, torque singular state and modal force singular state are defined and visualized to demonstrate the singularity. Numerical examples of several typical CMGs configurations on a gyroelastic body are given. Finally, a steering law allowing output error is designed and applied to the vibration suppression of a plate with distributed CMGs.

Workforce flexibility - in defence of professional healthcare work.

Science.gov (United States)

Wise, Sarah; Duffield, Christine; Fry, Margaret; Roche, Michael

2017-06-19

Purpose The desirability of having a more flexible workforce is emphasised across many health systems yet this goal is as ambiguous as it is ubiquitous. In the absence of empirical studies in healthcare that have defined flexibility as an outcome, the purpose of this paper is to draw on classic management and sociological theory to reduce this ambiguity. Design/methodology/approach The paper uses the Weberian tool of "ideal types". Key workforce reforms are held against Atkinson's model of functional flexibility which aims to increase responsiveness and adaptability through multiskilling, autonomy and teams; and Taylorism which seeks stability and reduced costs through specialisation, fragmentation and management control. Findings Appeals to an amorphous goal of increasing workforce flexibility make an assumption that any reform will increase flexibility. However, this paper finds that the work of healthcare professionals already displays most of the essential features of functional flexibility but many widespread reforms are shifting healthcare work in a Taylorist direction. This contradiction is symptomatic of a failure to confront inevitable trade-offs in reform: between the benefits of specialisation and the costs of fragmentation; and between management control and professional autonomy. Originality/value The paper questions the conventional conception of "the problem" of workforce reform as primarily one of professional control over tasks. Holding reforms against the ideal types of Taylorism and functional flexibility is a simple, effective way the costs and benefits of workforce reform can be revealed.

Flexible Working and Couples' Coordination of Time Schedules

OpenAIRE

Bryan, Mark L.; Sevilla Sanz, Almudena

2014-01-01

Using previously unexploited data on time scheduling in the employment and household contexts, we investigate the effect of flexible working on couples' coordination of their daily work time schedules in the UK. We consider three distinct dimensions of flexible working: flexibility of daily start and finish times (flexitime), flexibility of work times over the year (annualised hours), and generalised control of working hours. We find that in couples with flexitime there is greater spouse sync...

Controllable preparation of TiO{sub 2} nanowire arrays on titanium mesh for flexible dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Liu, Wenwu; Lu, Hui; Zhang, Mei; Guo, Min, E-mail: guomin@ustb.edu.cn

2015-08-30

Graphical abstract: TiO{sub 2} nanowire arrays with controlled morphology and density have been synthesized on Ti mesh substrates by hydrothermal approach for flexible dye-sensitized solar cells which showed well photovoltaic efficiency of 3.42%. - Highlights: • Flexible titanium mesh was first used for hydrothermal preparation of TiO{sub 2} NWAs. • The formation mechanism of the TiO{sub 2} nanostructures was discussed. • The density, average diameter, and morphology of TiO{sub 2} NWAs can be controlled. • The effects of the sensitization temperature and time on the properties were studied. - Abstract: TiO{sub 2} nanowire arrays (NWAs) with an average diameter of 80 nm have been successfully synthesized on titanium (Ti) mesh substrates via hydrothermal method. The effects of preparing conditions such as concentration of NaOH solution, reaction time, and hydrothermal temperature on the growth of TiO{sub 2} nanoarrays and its related photovoltaic properties were systematically investigated by scanning electron microscopy, X-ray diffraction, and photovoltaic properties test. The growth mechanism of the Ti mesh-supported TiO{sub 2} nanostructures was discussed in detail. Moreover, a parametric study was performed to determine the optimized temperature and time of the dye sensitized process for the flexible dye-sensitized solar cell (DSSC). It is demonstrated that hydrothermal parameters had obvious influence on the morphology and growth density of the as-prepared TiO{sub 2} nanoarrays. In addition, the performance of the flexible DSSC depended strongly on the sensitization temperature and time. By utilizing Ti mesh-supported TiO{sub 2} NWAs (with a length of about 14 μm) as a photoanode, the flexible DSSC with a short circuit current density of 10.49 mA cm{sup −2}, an open-circuit voltage of 0.69 V, and an overall power conversion efficiency of 3.42% was achieved.

Dynamic pricing and inventory control with delivery flexibility

DEFF Research Database (Denmark)

Chen, Wen; He, Ying

2018-01-01

We study a multi-period inventory system with price-sensitive demand and uncertain supplier, focusing on the advantage of delivery flexibility. The optimal pricing and inventory replenishment decisions are explored. We also investigate the changes of marginal profit, optimal order quantities...

Color identification and fuzzy reasoning based monitoring and controlling of fermentation process of branched chain amino acid

Science.gov (United States)

Ma, Lei; Wang, Yizhong; Xu, Qingyang; Huang, Huafang; Zhang, Rui; Chen, Ning

2009-11-01

The main production method of branched chain amino acid (BCAA) is microbial fermentation. In this paper, to monitor and to control the fermentation process of BCAA, especially its logarithmic phase, parameters such as the color of fermentation broth, culture temperature, pH, revolution, dissolved oxygen, airflow rate, pressure, optical density, and residual glucose, are measured and/or controlled and/or adjusted. The color of fermentation broth is measured using the HIS color model and a BP neural network. The network's input is the histograms of hue H and saturation S, and output is the color description. Fermentation process parameters are adjusted using fuzzy reasoning, which is performed by inference rules. According to the practical situation of BCAA fermentation process, all parameters are divided into four grades, and different fuzzy rules are established.

Modeling and Analysis of an Air-Breathing Flexible Hypersonic Vehicle

Directory of Open Access Journals (Sweden)

Xi-bin Zhang

2014-01-01

Full Text Available By using light-weighted material in hypersonic vehicle, the vehicle body can be easily deformed. The mutual couplings in aerodynamics, flexible structure, and propulsion system will bring great challenges for vehicle modeling. In this work, engineering estimated method is used to calculate the aerodynamic forces, moments, and flexible modes to get the physics-based model of an air-breathing flexible hypersonic vehicle. The model, which contains flexible effects and viscous effects, can capture the physical characteristics of high-speed flight. To overcome the analytical intractability of the model, a simplified control-oriented model of the hypersonic vehicle is presented with curve fitting approximations. The control-oriented model can not only reduce the complexity of the model, but also retain aero-flexible structure-propulsion interactions of the physics-based model and can be applied for nonlinear control.

Architecture, Assembly, and Emerging Applications of Branched Functional Polyelectrolytes and Poly(ionic liquid)s.

Science.gov (United States)

Xu, Weinan; Ledin, Petr A; Shevchenko, Valery V; Tsukruk, Vladimir V

2015-06-17

Branched polyelectrolytes with cylindrical brush, dendritic, hyperbranched, grafted, and star architectures bearing ionizable functional groups possess complex and unique assembly behavior in solution at surfaces and interfaces as compared to their linear counterparts. This review summarizes the recent developments in the introduction of various architectures and understanding of the assembly behavior of branched polyelectrolytes with a focus on functional polyelectrolytes and poly(ionic liquid)s with responsive properties. The branched polyelectrolytes and poly(ionic liquid)s interact electrostatically with small molecules, linear polyelectrolytes, or other branched polyelectrolytes to form assemblies of hybrid nanoparticles, multilayer thin films, responsive microcapsules, and ion-conductive membranes. The branched structures lead to unconventional assemblies and complex hierarchical structures with responsive properties as summarized in this review. Finally, we discuss prospectives for emerging applications of branched polyelectrolytes and poly(ionic liquid)s for energy harvesting and storage, controlled delivery, chemical microreactors, adaptive surfaces, and ion-exchange membranes.

An artificial flexible robot arm based on pneumatic muscle actuators

Directory of Open Access Journals (Sweden)

Renn Jyh-Chyang

2017-01-01

Full Text Available The purpose of this paper is to develop a novel human-friendly artificial flexible robot arm using four parallel-connected pneumatic muscle actuators (PMAs. The PMA is a flexible silicone rubber actuator which has some behaviors nearest to the real biological muscle including translational and rotational motions. An inverse kinematic model for the motion control is also developed. Finally, from experiment results, it is proved that not only the axial contraction control of a single PMA but also the attitude control of the whole pneumatic flexible robot arm using PID controller are satisfactory.

Graphene as a flexible template for controlling magnetic interactions between metal atoms.

Science.gov (United States)

Lee, Sungwoo; Kim, Dongwook; Robertson, Alex W; Yoon, Euijoon; Hong, Suklyun; Ihm, Jisoon; Yu, Jaejun; Warner, Jamie H; Lee, Gun-Do

2017-03-01

Metal-doped graphene produces magnetic moments that have potential application in spintronics. Here we use density function theory computational methods to show how the magnetic interaction between metal atoms doped in graphene can be controlled by the degree of flexure in a graphene membrane. Bending graphene by flexing causes the distance between two substitutional Fe atoms covalently bonded in graphene to gradually increase and these results in the magnetic moment disappearing at a critical strain value. At the critical strain, a carbon atom can enter between the two Fe atoms and blocks the interaction between relevant orbitals of Fe atoms to quench the magnetic moment. The control of interactions between doped atoms by exploiting the mechanical flexibility of graphene is a unique approach to manipulating the magnetic properties and opens up new opportunities for mechanical-magnetic 2D device systems.

Mechanism and Growth of Flexible ZnO Nanostructure Arrays in a Facile Controlled Way

Directory of Open Access Journals (Sweden)

Yangping Sheng

2011-01-01

Full Text Available Nanostructure arrays-based flexible devices have revolutionary impacts on the application of traditional semiconductor devices. Here, a one-step method to synthesize flexible ZnO nanostructure arrays on Zn-plated flexible substrate in Zn(NO32/NH3⋅H2O solution system at 70–90∘C was developed. We found out that the decomposition of Zn(OH2 precipitations, formed in lower NH3⋅H2O concentration, in the bulk solution facilitates the formation of flower-like structure. In higher temperature, 90∘C, ZnO nanoplate arrays were synthesized by the hydrolysis of zinc hydroxide. Highly dense ZnO nanoparticale layer formed by the reaction of NH3⋅H2O with Zn plating layer in the initial self-seed process could improve the vertical alignment of the nanowires arrays. The diameter of ZnO nanowire arrays, from 200 nm to 60 nm, could be effectively controlled by changing the stability of Zn(NH342+ complex ions by varying the ratio of Zn(NO32 to NH3⋅H2O which further influence the release rate of Zn2+ ions. This is also conformed by different amounts of the Zn vacancy as determined by different UV emissions of the PL spectra in the range of 380–403 nm.

Health and psychosocial effects of flexible working hours.

Science.gov (United States)

Janssen, Daniela; Nachreiner, Friedhelm

2004-12-01

To examine whether any impairments in health and social lives can be found under different kinds of flexible working hours, and whether such effects are related to specific characteristics of these working hours. Two studies -- a company based survey (N=660) and an internet survey (N=528) -- have been conducted. The first one was a questionnaire study (paper and pencil) on employees working under some 'typical' kinds of different flexible working time arrangements in different companies and different occupational fields (health care, manufacturing, retail, administration, call centres). The second study was an internet-based survey, using an adaptation of the questionnaire from the first study. The results of both studies consistently show that high variability of working hours is associated with increased impairments in health and well-being and this is especially true if this variability is company controlled. These effects are less pronounced if variability is self-controlled; however, autonomy does not compensate the effects of variability. Recommendations for an appropriate design of flexible working hours should be developed in order to minimize any impairing effects on health and psychosocial well-being; these recommendations should include -- besides allowing for discretion in controlling one's (flexible) working hours -- that variability in flexible working hours should be kept low (or at least moderate), even if this variability is self-controlled.

Backstepping boundary control: an application to the suppression of flexible beam vibration

Science.gov (United States)

Boonkumkrong, Nipon; Asadamongkon, Pichai; Chinvorarat, Sinchai

2018-01-01

This paper presents a backstepping boundary control for vibration suppression of flexible beam. The applications are such as industrial robotic arms, space structures, etc. Most slender beams can be modelled using a shear beam. The shear beam is more complex than the conventional Euler-Bernoulli beam in that a shear deformation is additionally taken into account. At present, the application of this method in industry is rather limited, because the application of controllers to the beam is difficult. In this research, we use the shear beam with moving base as a model. The beam is cantilever type. This design method allows us to deal directly with the beam’s partial differential equations (PDEs) without resorting to approximations. An observer is used to estimate the deflections along the beam. Gain kernel of the system is calculated and then used in the control law design. The control setup is anti-collocation, i.e. a sensor is placed at the beam tip and an actuator is placed at the beam moving base. Finite difference equations are used to solve the PDEs and the partial integro-differential equations (PIDEs). Control parameters are varied to see their influences that affect the control performance. The results of the control are presented via computer simulation to verify that the control scheme is effective.

Flexibility in water management as an intra-organisational issue

NARCIS (Netherlands)

Wessel, van M.; Buuren, van R.; Woerkum, van C.

2015-01-01

This paper is a case study of a team of Dutch water managers who saw that to achieve flexibility in planning they needed to engage with organisational control requirements. Rather than approaching flexibility normatively, as much planning literature does, this paper presents a case of flexibility

Research on Control Strategy of Complex Systems through VSC-HVDC Grid Parallel Device

Directory of Open Access Journals (Sweden)

Xue Mei-Juan

2014-07-01

Full Text Available After the completion of grid parallel, the device can turn to be UPFC, STATCOM, SSSC, research on the conversion circuit and transform method by corresponding switching operation. Accomplish the grid parallel and comprehensive control of the tie-line and stable operation and control functions of grid after parallel. Defines the function select operation switch matrix and grid parallel system branch variable, forming a switch matrix to achieve corresponding function of the composite system. Formed a criterion of the selection means to choose control strategy according to the switch matrix, to accomplish corresponding function. Put the grid parallel, STATCOM, SSSC and UPFC together as a system, improve the stable operation and flexible control of the power system.

A randomized controlled trial: branched-chain amino acid levels and glucose metabolism in patients with obesity and sleep apnea.

Science.gov (United States)

Barceló, Antonia; Morell-Garcia, Daniel; Salord, Neus; Esquinas, Cristina; Pérez, Gerardo; Pérez, Antonio; Monasterio, Carmen; Gasa, Merce; Fortuna, Ana Maria; Montserrat, Josep Maria; Mayos, Mercedes

2017-12-01

There is evidence that changes in branched-chain amino acid (BCAA) levels may correlate with the efficacy of therapeutic interventions for affecting improvement in metabolic control. The objective of this study was to evaluate whether serum concentrations of BCAAs (leucine, isoleucine, valine) could mediate in insulin sensitivity and glucose tolerance after continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnea (OSA). A prospective randomized controlled trial of OSA patients with morbid obesity was conducted. Eighty patients were randomized into two groups: 38 received conservative treatment and 42 received CPAP treatment for 12 weeks. Plasma levels of BCAA, glucose tolerance and insulin resistance were evaluated at baseline and after treatment. After treatment, significant decreases of leucine levels were observed in both groups when compared with baseline levels (P fasting plasma glucose and glycosylated haemoglobin values only in the conservative group (P < 0.05). In summary, we found that the treatment with CPAP for 12 weeks caused similar changes in circulating BCAAs concentrations to conservative treatment and a differential metabolic response of CPAP and conservative treatment was observed between the relationship of BCAAs and glucose homeostasis. Additional studies are needed to determine the interplay between branched-chain amino acids and glucose metabolism in patients with sleep apnea. © 2017 European Sleep Research Society.

Adaptive super twisting vibration control of a flexible spacecraft with state rate estimation

Science.gov (United States)

Malekzadeh, Maryam; Karimpour, Hossein

2018-05-01

The robust attitude and vibration control of a flexible spacecraft trying to perform accurate maneuvers in spite of various sources of uncertainty is addressed here. Difficulties for achieving precise and stable pointing arise from noisy onboard sensors, parameters indeterminacy, outer disturbances as well as un-modeled or hidden dynamics interactions. Based on high-order sliding-mode methods, the non-minimum phase nature of the problem is dealt with through output redefinition. An adaptive super-twisting algorithm (ASTA) is incorporated with its observer counterpart on the system under consideration to get reliable attitude and vibration control in the presence of sensor noise and momentum coupling. The closed-loop efficiency is verified through simulations under various indeterminate situations and got compared to other methods.

Short Lives with Long-Lasting Effects: Filopodia Protrusions in Neuronal Branching Morphogenesis.

Directory of Open Access Journals (Sweden)

George Leondaritis

Full Text Available The branching behaviors of both dendrites and axons are part of a neuronal maturation process initiated by the generation of small and transient membrane protrusions. These are highly dynamic, actin-enriched structures, collectively called filopodia, which can mature in neurons to form stable branches. Consequently, the generation of filopodia protrusions is crucial during the formation of neuronal circuits and involves the precise control of an interplay between the plasma membrane and actin dynamics. In this issue of PLOS Biology, Hou and colleagues identify a Ca2+/CaM-dependent molecular machinery in dendrites that ensures proper targeting of branch formation by activation of the actin nucleator Cobl.

The efficiency of bank branches

OpenAIRE

Omid Takbiri; Mohammad Mohammadi; Bahman Naderi

2015-01-01

Banking industry has significant contribution in development of economies of developing countries. Most banks execute their operations through different branches. Therefore it is important to measure the relative efficiencies of these branches. Data envelopment analysis (DEA) is one of the most useful tools in measuring banks’ performance. The present paper aims to extract ranking pattern of banks based on performance evaluation using DEA analysis. In the present research, 120 bank branches o...

Controller design for flexible, distributed parameter mechanical arms via combined state space and frequency domain techniques

Science.gov (United States)

Book, W. J.; Majett, M.

1982-01-01

The potential benefits of the ability to control more flexible mechanical arms are discussed. A justification is made in terms of speed of movement. A new controller design procedure is then developed to provide this capability. It uses both a frequency domain representation and a state variable representation of the arm model. The frequency domain model is used to update the modal state variable model to insure decoupled states. The technique is applied to a simple example with encouraging results.

A Flexible framework for forward and inverse modeling of stormwater control measures

Science.gov (United States)

Aflaki, S.; Massoudieh, A.

2016-12-01

Models that allow for design considerations of green infrastructure (GI) practices to control stormwater runoff and associated contaminants have received considerable attention in recent years. While popular, generally, the GI models are relatively simplistic. However, GI model predictions are being relied upon by many municipalities and State/Local agencies to make decisions about grey vs. green infrastructure improvement planning. Adding complexity to GI modeling frameworks may preclude their use in simpler urban planning situations. Therefore, the goal here was to develop a sophisticated, yet flexible tool that could be used by design engineers and researchers to capture and explore the effect of design factors and properties of the media used in the performance of GI systems at a relatively small scale. We deemed it essential to have a flexible GI modeling tool that is capable of simulating GI system components and specific biophysical processes affecting contaminants such as reactions, and particle-associated transport accurately while maintaining a high degree of flexibly to account for the myriad of GI alternatives. The mathematical framework for a stand-alone GI performance assessment tool has been developed and will be demonstrated. The process-based model framework developed here can be used to model a diverse range of GI practices such as green roof, retention pond, bioretention, infiltration trench, permeable pavement and other custom-designed combinatory systems. Four demonstration applications covering a diverse range of systems will be presented. The example applications include a evaluating hydraulic performance of a complex bioretention system, hydraulic analysis of porous pavement system, flow colloid-facilitated transport, reactive transport and groundwater recharge underneath an infiltration pond and finally reactive transport and bed-sediment interactions in a wetland system will be presented.

Flexibility.

Science.gov (United States)

Humphrey, L. Dennis

1981-01-01

Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

Branch Development of Five-Year-Old Betula alnoides Plantations in Response to Planting Density

Directory of Open Access Journals (Sweden)

Chun-Sheng Wang

2018-01-01

Full Text Available Branch development in the lower part of stem is critical to both early stem growth and wood quality of the most valuable section of tree, and its regulation through planting density has always been greatly concerned. Here the effect of planting density on branch development was examined in a five-year-old plantation of Betula alnoides with six planting densities (625, 833, 1111, 1250, 1667, and 2500 stems per hectare (sph in Guangdong Province, South China. Branch quantity (number, proportion, and density, morphology (diameter, length, and angle, position (height and orientation, and branch status (dead or alive were investigated for 54 dominant or co-dominant trees under six treatments of planting density after the growth of each tree was measured. Factors influencing branch development were also explored by mixed modelling. The results showed that the mean tree heights of 1250 and 1667 sph treatments were higher than those of other planting density treatments. The quantity of live branches decreased with increasing planting density. However, planting density had no significant effect on the number of all branches, and there existed no remarkable difference in branch number and proportion among four orientations. As for branch morphology, only the largest branch diameter had a significantly negative correlation with planting density. In addition, high planting density significantly increased the height of the largest branch within the crown. Mixed effects models indicated that branch diameter, length, and angle were closely correlated with each other, and they were all in positively significant correlation to the branch height at the stem section below six meters. It was concluded that properly increasing planting density will promote natural pruning, improve early branch control, and be beneficial for wood production from the most valuable section of the stem.

Herbivore-induced volatiles in the perennial shrub, Vaccinium corymbosum, and their role in inter-branch signaling.

Science.gov (United States)

Rodriguez-Saona, Cesar R; Rodriguez-Saona, Luis E; Frost, Christopher J

2009-02-01

Herbivore feeding activates plant defenses at the site of damage as well as systemically. Systemic defenses can be induced internally by signals transported via phloem or xylem, or externally transmitted by volatiles emitted from the damaged tissues. We investigated the role of herbivore-induced plant volatiles (HIPVs) in activating a defense response between branches in blueberry plants. Blueberries are perennial shrubs that grow by initiating adventitious shoots from a basal crown, which produce new lateral branches. This type of growth constrains vascular connections between shoots and branches within plants. While we found that leaves within a branch were highly connected, vascular connectivity was limited between branches within shoots and absent between branches from different shoots. Larval feeding by gypsy moth, exogenous methyl jasmonate, and mechanical damage differentially induced volatile emissions in blueberry plants, and there was a positive correlation between amount of insect damage and volatile emission rates. Herbivore damage did not affect systemic defense induction when we isolated systemic branches from external exposure to HIPVs. Thus, internal signals were not capable of triggering systemic defenses among branches. However, exposure of branches to HIPVs from an adjacent branch decreased larval consumption by 70% compared to those exposed to volatiles from undamaged branches. This reduction in leaf consumption did not result in decreased volatile emissions, indicating that leaves became more responsive to herbivory (or "primed") after being exposed to HIPVs. Chemical profiles of leaves damaged by gypsy moth caterpillars, exposed to HIPVs, or non-damaged controls revealed that HIPV-exposed leaves had greater chemical similarities to damaged leaves than to control leaves. Insect-damaged leaves and young HIPV-exposed leaves had higher amounts of endogenous cis-jasmonic acid compared to undamaged and non-exposed leaves, respectively. Our results

Thermostat Controlled Loads Flexibility Assessment for Enabling Load Shifting – An Experimental Proof in a Low Voltage Grid

DEFF Research Database (Denmark)

Lakshmanan, Venkatachalam; Marinelli, Mattia; Kosek, Anna M.

2017-01-01

This paper investigates the usability of thermostat controlled domestic appliances for load shift in LV distribution grids. The proposed method uses refrigerators for the demonstration of adaptive load prediction to estimate its flexibility and perform scheduling based on load threshold limit. Tw...

A time domain inverse dynamic method for the end point tracking control of a flexible manipulator

Science.gov (United States)

Kwon, Dong-Soo; Book, Wayne J.

1991-01-01

The inverse dynamic equation of a flexible manipulator was solved in the time domain. By dividing the inverse system equation into the causal part and the anticausal part, we calculated the torque and the trajectories of all state variables for a given end point trajectory. The interpretation of this method in the frequency domain was explained in detail using the two-sided Laplace transform and the convolution integral. The open loop control of the inverse dynamic method shows an excellent result in simulation. For real applications, a practical control strategy is proposed by adding a feedback tracking control loop to the inverse dynamic feedforward control, and its good experimental performance is presented.

Quality control process improvement of flexible printed circuit board by FMEA

Science.gov (United States)

Krasaephol, Siwaporn; Chutima, Parames

2018-02-01

This research focuses on the quality control process improvement of Flexible Printed Circuit Board (FPCB), centred around model 7-Flex, by using Failure Mode and Effect Analysis (FMEA) method to decrease proportion of defective finished goods that are found at the final inspection process. Due to a number of defective units that were found at the final inspection process, high scraps may be escaped to customers. The problem comes from poor quality control process which is not efficient enough to filter defective products from in-process because there is no In-Process Quality Control (IPQC) or sampling inspection in the process. Therefore, the quality control process has to be improved by setting inspection gates and IPCQs at critical processes in order to filter the defective products. The critical processes are analysed by the FMEA method. IPQC is used for detecting defective products and reducing chances of defective finished goods escaped to the customers. Reducing proportion of defective finished goods also decreases scrap cost because finished goods incur higher scrap cost than work in-process. Moreover, defective products that are found during process can reflect the abnormal processes; therefore, engineers and operators should timely solve the problems. Improved quality control was implemented for 7-Flex production lines from July 2017 to September 2017. The result shows decreasing of the average proportion of defective finished goods and the average of Customer Manufacturers Lot Reject Rate (%LRR of CMs) equal to 4.5% and 4.1% respectively. Furthermore, cost saving of this quality control process equals to 100K Baht.

Dynamic Crack Branching - A Photoelastic Evaluation,

Science.gov (United States)

1982-05-01

0.41 mPai and a 0.18 MPa, and predicted a theoretical kinking angle of 84°whichagreed well with experimentally measured angle. After crack kinking...Consistent crack branching’at KIb = 2.04 MPaI -i- and r = 1.3 mm verified this crack branching criterion. The crack branching angle predicted by--.’ DD

Indirect intelligent sliding mode control of a shape memory alloy actuated flexible beam using hysteretic recurrent neural networks

International Nuclear Information System (INIS)

Hannen, Jennifer C; Buckner, Gregory D; Crews, John H

2012-01-01

This paper introduces an indirect intelligent sliding mode controller (IISMC) for shape memory alloy (SMA) actuators, specifically a flexible beam deflected by a single offset SMA tendon. The controller manipulates applied voltage, which alters SMA tendon temperature to track reference bending angles. A hysteretic recurrent neural network (HRNN) captures the nonlinear, hysteretic relationship between SMA temperature and bending angle. The variable structure control strategy provides robustness to model uncertainties and parameter variations, while effectively compensating for system nonlinearities, achieving superior tracking compared to an optimized PI controller. (paper)

High-bandwidth and flexible tracking control for precision motion with application to a piezo nanopositioner.

Science.gov (United States)

Feng, Zhao; Ling, Jie; Ming, Min; Xiao, Xiao-Hui

2017-08-01

For precision motion, high-bandwidth and flexible tracking are the two important issues for significant performance improvement. Iterative learning control (ILC) is an effective feedforward control method only for systems that operate strictly repetitively. Although projection ILC can track varying references, the performance is still limited by the fixed-bandwidth Q-filter, especially for triangular waves tracking commonly used in a piezo nanopositioner. In this paper, a wavelet transform-based linear time-varying (LTV) Q-filter design for projection ILC is proposed to compensate high-frequency errors and improve the ability to tracking varying references simultaneously. The LVT Q-filter is designed based on the modulus maximum of wavelet detail coefficients calculated by wavelet transform to determine the high-frequency locations of each iteration with the advantages of avoiding cross-terms and segmenting manually. The proposed approach was verified on a piezo nanopositioner. Experimental results indicate that the proposed approach can locate the high-frequency regions accurately and achieve the best performance under varying references compared with traditional frequency-domain and projection ILC with a fixed-bandwidth Q-filter, which validates that through implementing the LTV filter on projection ILC, high-bandwidth and flexible tracking can be achieved simultaneously by the proposed approach.

Tracking error constrained robust adaptive neural prescribed performance control for flexible hypersonic flight vehicle

Directory of Open Access Journals (Sweden)

Zhonghua Wu

2017-02-01

Full Text Available A robust adaptive neural control scheme based on a back-stepping technique is developed for the longitudinal dynamics of a flexible hypersonic flight vehicle, which is able to ensure the state tracking error being confined in the prescribed bounds, in spite of the existing model uncertainties and actuator constraints. Minimal learning parameter technique–based neural networks are used to estimate the model uncertainties; thus, the amount of online updated parameters is largely lessened, and the prior information of the aerodynamic parameters is dispensable. With the utilization of an assistant compensation system, the problem of actuator constraint is overcome. By combining the prescribed performance function and sliding mode differentiator into the neural back-stepping control design procedure, a composite state tracking error constrained adaptive neural control approach is presented, and a new type of adaptive law is constructed. As compared with other adaptive neural control designs for hypersonic flight vehicle, the proposed composite control scheme exhibits not only low-computation property but also strong robustness. Finally, two comparative simulations are performed to demonstrate the robustness of this neural prescribed performance controller.

Out-reach in-space technology experiments program: Control of flexible robot manipulators in zero gravity, experiment definition phase

Science.gov (United States)

Phillips, Warren F.

1989-01-01

The results obtained show that it is possible to control light-weight robots with flexible links in a manner that produces good response time and does not induce unacceptable link vibrations. However, deflections induced by gravity cause large static position errors with such a control system. For this reason, it is not possible to use this control system for controlling motion in the direction of gravity. The control system does, on the other hand, have potential for use in space. However, in-space experiments will be needed to verify its applicability to robots moving in three dimensions.

Flexibility of Knee Joint Muscles in Women with Knee Osteoarthritis and Healthy Controls

Directory of Open Access Journals (Sweden)

Sara Abolahrari Shirazi

2015-09-01

Full Text Available Background: Osteoarthritis is one of the most common diseases in synovial joints. Due to high loading forces during weight-bearing activities, the knee joint is prone to degenerative processes. This study aimed to compare the flexibility of muscles around the knee joint in patients with knee osteoarthritis with those of healthy individuals. Methods: Twenty-three women with bilateral knee osteoarthritis and 23 healthy women matched with the patient group for age, height and weight participated in this study. Flexibility of the quadriceps, hamstring, iliotibial band, adductor and gastrocnemius muscles was evaluated with a goniometric device. Pain intensity was assessed with a visual analogue scale. The data were analyzed with independent t-tests to compare the two groups, and Pearson correlation coefficient was calculated to correlate muscle flexibility and pain intensity. Results: significant lower flexibility of the bilateral quadriceps muscles was found in patients compared to healthy women (P<0.05. No significant differences were detected between groups regarding other muscles. Quadriceps flexibility correlated significantly with pain intensity in patients (P<0.001. Conclusion: In patients with osteoarthritis, quadriceps flexibility may be decreased although other muscles may remain unaffected. Quadriceps stretching is thus a potentially important component of treatment, which may influence pain reduction in these patients.

Influence of hinge point on flexible flap aerodynamic performance

International Nuclear Information System (INIS)

Zhao, H Y; Ye, Z; Wu, P; Li, C

2013-01-01

Large scale wind turbines lead to increasing blade lengths and weights, which presents new challenges for blade design. This paper selects NREL S809 airfoil, uses the parameterized technology to realize the flexible trailing edge deformation, researches the static aerodynamic characteristics of wind turbine blade airfoil with flexible deformation, and the dynamic aerodynamic characteristics in the process of continuous deformation, analyses the influence of hinge point position on flexible flap aerodynamic performance, in order to further realize the flexible wind turbine blade design and provides some references for the active control scheme. The results show that compared with the original airfoil, proper trailing edge deformation can improve the lift coefficient, reduce the drag coefficient, and thereby more efficiently realize flow field active control. With hinge point moving forward, total aerodynamic performance of flexible flap improves. Positive swing angle can push the transition point backward, thus postpones the occurrence of the transition phenomenon

Flexibility in radiation protection legislation -the UK approach

International Nuclear Information System (INIS)

Beaver, P.F.; Gill, J.R.

1980-01-01

The case for flexibility in the formulation of radiation protection legislation and that for precise invariable requirements which are applicable to all users of ionising radiations are presented. It is asserted that greater participation on the part of persons affected in the shaping of legislation brings with it a commitment to flexibility if consensus is to be achieved. The nature of the participative and consultative processes in the UK is described. The means by which flexibility will be inbuilt into future UK legislation are discussed, taking as examples, three particular areas: a) Notification of use of ionising radiations, where flexibility needs to be introduced to take care of improved knowledge of potential risk, the avoidance of bureaucratic procedures, and the wide variation in practice from one work activity to another; b) The definition of controlled areas, where flexibility is needed to cope with the wide range of potential use situations, yet if controlled areas are to be the route to defining Category A workers, where that flexibility must be restrained to ensure proper categorysation and effective enforcement; c) The criteria for the need to appoint and for the selection of radiation protection advisers where flexibility must be invoked to ensure that any particular task is matched by the quality of the radiation protection adviser concerned. It is concluded that the proposed UK legislation will achieve flexibility where this is appropriate and cost-effective and on the other hand demand adherence to strictly expressed levels of exposure where that is appropriate. (author)

Effects of Pilates Training on Lumbo-Pelvic Stability and Flexibility

Science.gov (United States)

Phrompaet, Sureeporn; Paungmali, Aatit; Pirunsan, Ubon; Sitilertpisan, Patraporn

2011-01-01

Purpose This study was performed to assess and compare the effects of Pilates exercise on flexibility and lumbo-pelvic movement control between the Pilates training and control groups. Methods A randomized single-blinded controlled design was utilized in the study. Forty healthy male and female volunteers (mean age 31.65±6.21 years) were randomly divided into Pilates-based training (20 subjects) and the control groups (20 subjects). The Pilates group attended 45-minute training sessions, 2 times per week, for a period of 8 weeks. Flexibility and lumbo-pelvic stability tests were determined as outcome measures using a standard “sit and reach test” and “pressure biofeedback” respectively at 0, 4 and 8 weeks of the study. Results The results showed that the Pilates training group improved flexibility significantly (PPilates group passing the lumbo-pelvic stability test at 4 and 8 weeks of training periods respectively. No subjects from the control group passed the test at any stages. Conclusions Pilates can be used as an adjunctive exercise program to improve flexibility, enhance control-mobility of trunk and pelvic segments. It may also prevent and attenuate the predisposition to axial musculoskeletal injury. PMID:22375213

Evaluation of flexible endoscope steering using haptic guidance

NARCIS (Netherlands)

Reilink, Rob; Stramigioli, Stefano; Kappers, Astrid M L; Misra, Sarthak

Background: Steering the tip of a flexible endoscope relies on the physician's dexterity and experience. For complex flexible endoscopes, conventional controls may be inadequate. Methods: A steering method based on a multi-degree-of-freedom haptic device is presented. Haptic cues are generated based

Evaluation of flexible endoscope steering using haptic guidance

NARCIS (Netherlands)

Reilink, Rob; Stramigioli, Stefano; Kappers, Astrid M.L.; Misra, Sarthak

2011-01-01

Background - Steering the tip of a flexible endoscope relies on the physician’s dexterity and experience. For complex flexible endoscopes, conventional controls may be inadequate. Methods - A steering method based on a multi-degree-of-freedom haptic device is presented. Haptic cues are generated

Tree Branching: Leonardo da Vinci's Rule versus Biomechanical Models

Science.gov (United States)

Minamino, Ryoko; Tateno, Masaki

2014-01-01

This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule. PMID:24714065

Tree branching: Leonardo da Vinci's rule versus biomechanical models.

Science.gov (United States)

Minamino, Ryoko; Tateno, Masaki

2014-01-01

This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule.

IEA EBC Annex 67 Energy Flexible Buildings

DEFF Research Database (Denmark)

Marszal, Anna Joanna; Jensen, Søren Østergaard

2016-01-01

know ledge on and demonstration of the Energy Flexibility Buildings can provide for the energy grids as well of to identify critical aspects and possible solutions to manage this Energy Flexibility. The paper discusses the background, the aims and the work plan of IEA (International Energy Agency) EBC......The foreseen large deployment of renewable energy sources may seriously affect the stability of energy grids. It will be necessary to control energy consumption to match instantaneous energy production. The built-in Energy Flexibility in buildings may be utilized for stabilizing the energy grids......, allowing for a larger roll out of renewable technologies. The Energy Flexibility of a building is the ability to manage its energy demand and generation according to local climate conditions, user needs and grid requirements. Energy Flexibility of buildings will thus allow for demand side management...

Folded plate assemblies with branching column supports : Interaction and control of overall shape

NARCIS (Netherlands)

Falk, A.; Turrin, M.; von Buelow, P.

2010-01-01

The work described in this paper aims at developing the interrelation and overall effects of interaction between a folded plate roof structure and a system of branching column supports. In the context of architectural performance it is of interest to discuss the effects of the material on

Additional chain-branching pathways in the low-temperature oxidation of branched alkanes

KAUST Repository

Wang, Zhandong

2015-12-31

Chain-branching reactions represent a general motif in chemistry, encountered in atmospheric chemistry, combustion, polymerization, and photochemistry; the nature and amount of radicals generated by chain-branching are decisive for the reaction progress, its energy signature, and the time towards its completion. In this study, experimental evidence for two new types of chain-branching reactions is presented, based upon detection of highly oxidized multifunctional molecules (HOM) formed during the gas-phase low-temperature oxidation of a branched alkane under conditions relevant to combustion. The oxidation of 2,5-dimethylhexane (DMH) in a jet-stirred reactor (JSR) was studied using synchrotron vacuum ultra-violet photoionization molecular beam mass spectrometry (SVUV-PI-MBMS). Specifically, species with four and five oxygen atoms were probed, having molecular formulas of C8H14O4 (e.g., diketo-hydroperoxide/keto-hydroperoxy cyclic ether) and C8H16O5 (e.g., keto-dihydroperoxide/dihydroperoxy cyclic ether), respectively. The formation of C8H16O5 species involves alternative isomerization of OOQOOH radicals via intramolecular H-atom migration, followed by third O2 addition, intramolecular isomerization, and OH release; C8H14O4 species are proposed to result from subsequent reactions of C8H16O5 species. The mechanistic pathways involving these species are related to those proposed as a source of low-volatility highly oxygenated species in Earth\\'s troposphere. At the higher temperatures relevant to auto-ignition, they can result in a net increase of hydroxyl radical production, so these are additional radical chain-branching pathways for ignition. The results presented herein extend the conceptual basis of reaction mechanisms used to predict the reaction behavior of ignition, and have implications on atmospheric gas-phase chemistry and the oxidative stability of organic substances. © 2015 The Combustion Institute.

Optimization of multi-branch switched diversity systems

KAUST Repository

Nam, Haewoon

2009-10-01

A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold, the optimal switching threshold is a function of both the average channel SNR and the number of diversity branches, where computing the optimal switching threshold is not a simple task when the number of diversity branches is high. The newly proposed multi-branch switched diversity system is based on a sequence of switching thresholds, instead of a single switching threshold, where a different diversity branch uses a different switching threshold for signal comparison. Thanks to the fact that each switching threshold in the sequence can be optimized only based on the number of the remaining diversity branches, the proposed system makes it easy to find these switching thresholds. Furthermore, some selected numerical and simulation results show that the proposed switched diversity system with the sequence of optimal switching thresholds outperforms the conventional system with the single optimal switching threshold. © 2009 IEEE.

Flexible voltage support control for three-phase distributed generation inverters under grid fault

DEFF Research Database (Denmark)

Camacho, Antonio; Castilla, Miguel; Miret, Jaume

2013-01-01

Operators describe the behavior of the energy source, regulating voltage limits and reactive power injection to remain connected and support the grid under fault. On the basis that different kinds of voltage sags require different voltage support strategies, a flexible control scheme for three phase grid...... connected inverters is proposed. In three phase balanced voltage sags, the inverter should inject reactive power in order to raise the voltage in all phases. In one or two phase faults, the main concern of the distributed generation inverter is to equalize voltages by reducing the negative symmetric...... sequence and clear the phase jump. Due to system limitations, a balance between these two extreme policies is mandatory. Thus, over-voltage and undervoltage can be avoided, and the proposed control scheme prevents disconnection while achieving the desired voltage support service. The main contribution...

Application of a passivity based control methodology for flexible joint robots to a simplified Space Shuttle RMS

Science.gov (United States)

Sicard, Pierre; Wen, John T.

1992-01-01

A passivity approach for the control design of flexible joint robots is applied to the rate control of a three-link arm modeled after the shoulder yaw joint of the Space Shuttle Remote Manipulator System (RMS). The system model includes friction and elastic joint couplings modeled as nonlinear springs. The basic structure of the proposed controller is the sum of a model-based feedforward and a model-independent feedback. A regulator approach with link state feedback is employed to define the desired motor state. Passivity theory is used to design a motor state-based controller to stabilize the error system formed by the feedforward. Simulation results show that greatly improved performance was obtained by using the proposed controller over the existing RMS controller.

Flexible Bronchoscopy.

Science.gov (United States)

Miller, Russell J; Casal, Roberto F; Lazarus, Donald R; Ost, David E; Eapen, George A

2018-03-01

Flexible bronchoscopy has changed the course of pulmonary medicine. As technology advances, the role of the flexible bronchoscope for both diagnostic and therapeutic indications is continually expanding. This article reviews the historical development of the flexible bronchoscopy, fundamental uses of the flexible bronchoscope as a tool to examine the central airways and obtain diagnostic tissue, and the indications, complications, and contraindications to flexible bronchoscopy. Copyright © 2017 Elsevier Inc. All rights reserved.

Auxin transport in the evolution of branching forms.

Science.gov (United States)

Harrison, C Jill

2017-07-01

Contents 545 I. 545 II. 546 III. 546 IV. 548 V. 548 VI. 549 VII. 549 Acknowledgements 549 References 549 SUMMARY: Branching is one of the most striking aspects of land plant architecture, affecting resource acquisition and yield. Polar auxin transport by PIN proteins is a primary determinant of flowering plant branching patterns regulating both branch initiation and branch outgrowth. Several lines of experimental evidence suggest that PIN-mediated polar auxin transport is a conserved regulator of branching in vascular plant sporophytes. However, the mechanisms of branching and auxin transport and relationships between the two are not well known outside the flowering plants, and the paradigm for PIN-regulated branching in flowering plants does not fit bryophyte gametophytes. The evidence reviewed here suggests that divergent auxin transport routes contributed to the diversification of branching forms in distinct land plant lineages. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Branch Width and Height Influence the Incorporation of Branches into Foraging Trails and Travel Speed in Leafcutter Ants Atta cephalotes (L.) (Hymenoptera: Formicidae).

Science.gov (United States)

Freeman, B M; Chaves-Campos, J

2016-06-01

Fallen branches are often incorporated into Atta cephalotes (L.) foraging trails to optimize leaf tissue transport rates and economize trail maintenance. Recent studies in lowlands show laden A. cephalotes travel faster across fallen branches than on ground, but more slowly ascending or descending a branch. The latter is likely because (1) it is difficult to travel up or downhill and (2) bottlenecks occur when branches are narrower than preceding trail. Hence, both branch height and width should determine whether branches decrease net travel times, but no study has evaluated it yet. Laden A. cephalotes were timed in relation to branch width and height across segments preceding, accessing, across, and departing a fallen branch in the highlands of Costa Rica. Ants traveled faster on branches than on cleared segments of trunk-trail, but accelerated when ascending or descending the branch-likely because of the absence of bottlenecks during the day in the highlands. Branch size did not affect ant speed in observed branches; the majority of which (22/24) varied from 11 to 120 mm in both height and width (average 66 mm in both cases). To determine whether ants exclude branches outside this range, ants were offered the choice between branches within this range and branches that were taller/wider than 120 mm. Ants strongly preferred the former. Our results indicate that A. cephalotes can adjust their speed to compensate for the difficulty of traveling on branch slopes. More generally, branch size should be considered when studying ant foraging efficiency.

Persistence-Based Branch Misprediction Bounds for WCET Analysis

DEFF Research Database (Denmark)

Puffitsch, Wolfgang

2015-01-01

Branch prediction is an important feature of pipelined processors to achieve high performance. However, it can lead to overly pessimistic worst-case execution time (WCET) bounds when being modeled too conservatively. This paper presents bounds on the number of branch mispredictions for local...... dynamic branch predictors. To handle interferences between branch instructions we use the notion of persistence, a concept that is also found in cache analyses. The bounds apply to branches in general, not only to branches that close a loop. Furthermore, the bounds can be easily integrated into integer...... linear programming formulations of the WCET problem. An evaluation on a number of benchmarks shows that with these bounds, dynamic branch prediction does not necessarily lead to higher WCET bounds than static prediction schemes....

Human spinal locomotor control is based on flexibly organized burst generators.

Science.gov (United States)

Danner, Simon M; Hofstoetter, Ursula S; Freundl, Brigitta; Binder, Heinrich; Mayr, Winfried; Rattay, Frank; Minassian, Karen

2015-03-01

samples of rhythmic patterns. The basic activation patterns can be interpreted as central drives implemented by spinal burst generators that impose specific spatiotemporally organized activation on the lumbosacral motor neuron pools. Our data thus imply that the human lumbar spinal cord circuits can form burst-generating elements that flexibly combine to obtain a wide range of locomotor outputs from a constant, repetitive input. It may be possible to use this flexibility to incorporate specific adaptations to gait and stance to improve locomotor control, even after severe central nervous system damage. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Customizing graphical user interface technology for spacecraft control centers

Science.gov (United States)

Beach, Edward; Giancola, Peter; Gibson, Steven; Mahmot, Ronald

1993-01-01

The Transportable Payload Operations Control Center (TPOCC) project is applying the latest in graphical user interface technology to the spacecraft control center environment. This project of the Mission Operations Division's (MOD) Control Center Systems Branch (CCSB) at NASA Goddard Space Flight Center (GSFC) has developed an architecture for control centers which makes use of a distributed processing approach and the latest in Unix workstation technology. The TPOCC project is committed to following industry standards and using commercial off-the-shelf (COTS) hardware and software components wherever possible to reduce development costs and to improve operational support. TPOCC's most successful use of commercial software products and standards has been in the development of its graphical user interface. This paper describes TPOCC's successful use and customization of four separate layers of commercial software products to create a flexible and powerful user interface that is uniquely suited to spacecraft monitoring and control.

Flexible Mode Control of Grid Connected Wind Energy Conversion System Using Wavelet

Directory of Open Access Journals (Sweden)

Bhavna Jain

2015-01-01

Full Text Available Small wind turbine systems offer services to critical loads during grid faults and also connected back to grid in normal condition. The connection of a wind energy conversion system to the grid requires a robust phase locked loop (PLL and continuous monitoring of the grid conditions such as overvoltage, undervoltage, overfrequency, underfrequency, and grid outages. This paper describes a flexible control operation to operate a small wind turbine in both stand-alone mode via planned islanding and grid connected mode as well. In particular, a proper monitoring and control algorithm is required for transition between the modes. A wavelet based energy function is used for detection of grid disturbances as well as recovery of grid so that transition between the modes is made. To obtain good power quality LCL filter is used to reduce ripples. PLL is used for synchronization whenever mode changes from stand-alone to grid connected. Simulation results from a 10 kW wind energy conversion system are included to show the usefulness of the proposed methods. The control method is tested by generated gate pulses for single phase bridge inverter using field programmable gate array (FPGA.

New developments in flexible cholesteric liquid crystal displays

Science.gov (United States)

Schneider, Tod; Davis, Donald J.; Franklin, Sean; Venkataraman, Nithya; McDaniel, Diaz; Nicholson, Forrest; Montbach, Erica; Khan, Asad; Doane, J. William

2007-02-01

Flexible Cholesteric liquid crystal displays have been rapidly maturing into a strong contender in the flexible display market. Encapsulation of the Cholesteric liquid crystal permits the use of flexible plastic substrates and roll-to-roll production. Recent advances include ultra-thin displays, laser-cut segmented displays of variable geometry, and smart card applications. Exciting technologies such as simultaneous laser-edge sealing and singulation enable high volume production, excellent quality control and non-traditional display geometries and formats.

Branched-chain fatty acid biosynthesis in a branched-chain amino acid aminotransferase mutant of Staphylococcus carnosus

DEFF Research Database (Denmark)

Beck, Hans Christian

2005-01-01

Fatty acid biosynthesis by a mutant strain of Staphylococcus carnosus deficient in branched-chain amino acid aminotransferase (IlvE) activity was analysed. This mutant was unable to produce the appropriate branched-chain alpha-ketoacid precursors for branched-chain fatty acid biosynthesis from...... in rich medium and growth in defined medium supplemented with 2-methylpropanoic acid lead to extensive alteration of the fatty acid composition in the cell membrane. In rich medium, a change from 51.7% to 17.1% anteiso-C15:0, and from 3.6% to 33.9% iso-C14:0 fatty acids as compared to the wild-type strain...... for 2-methylpropanoic acid production, revealing that the IlvE protein plays an important, but not essential role in the biosynthesis of branched-chain fatty acids and secondary metabolites in S. carnosus....

Flexible experimental FPGA based platform

DEFF Research Database (Denmark)

Andersen, Karsten Holm; Nymand, Morten

2016-01-01

This paper presents an experimental flexible Field Programmable Gate Array (FPGA) based platform for testing and verifying digital controlled dc-dc converters. The platform supports different types of control strategies, dc-dc converter topologies and switching frequencies. The controller platform...... interface supporting configuration and reading of setup parameters, controller status and the acquisition memory in a simple way. The FPGA based platform, provides an easy way within education or research to use different digital control strategies and different converter topologies controlled by an FPGA...

Silver nanocombs and branched nanowires formation in aqueous binary surfactants solution

International Nuclear Information System (INIS)

Umar, Akrajas Ali; Oyama, Munetaka; Salleh, Muhamad Mat; Majlis, Burhanuddin Yeop

2012-01-01

Branched nanocrystals, particularly nanocombs, are a unique 1D-morphology that is normally formed in polytypic materials, such as ZnO, and rarely occurs in the highly symmetric fcc metallic system. Here, we report the chemical synthesis of nanocombs of a highly symmetrical fcc silver system that is realized by reducing the silver ions in the presence of a mixture of silver nanoseeds and binary surfactants, namely cetyltrimethylammonium bromide (CTAB) and hexamethylenetetramine (hexamine or HMT), under an alkaline condition. The silver nanocombs feature a high-degree branching orientation toward a single direction with good branch-to-branch spacing. The nanocombs formation was very sensitive to the concentrations of CTAB, HMT and NaOH in the reaction in which, in a typical case, nanocombs or curly nanowires were produced by controlling the concentration of these chemicals in the reaction. We hypothesized that the branching could be due to: (i) a kind of polytypism in such highly symmetrical fcc nanocrystals that was enabled by a selective surfactant adhesion process on the growing crystalline plane and (ii) lattice defects or twinning induced growth redirection in the nanocrystals. The silver nanocombs might generate a peculiar characteristic that is probably superior to those produced by other morphologies, such as nanorods, nanowires, and so on. Thus, it should find extensive use in the currently existing applications.

Influence of inflow angle on flexible flap aerodynamic performance

International Nuclear Information System (INIS)

Zhao, H Y; Ye, Z; Li, Z M; Li, C

2013-01-01

Large scale wind turbines have larger blade lengths and weights, which creates new challenges for blade design. This paper selects NREL S809 airfoil, and uses the parameterized technology to realize the flexible trailing edge deformation, researches the dynamic aerodynamic characteristics in the process of continuous flexible deformation, analyses the influence of inflow angle on flexible flap aerodynamic performance, in order to further realize the flexible wind turbine blade design and provides some references for the active control scheme. The results show that compared with the original airfoil, proper trailing edge deformation can improve the lift coefficient, reduce the drag coefficient, and thereby more efficiently realize flow field active control. With inflow angle increases, dynamic lift-drag coefficient hysteresis loop shape deviation occurs, even turns into different shapes. Appropriate swing angle can improve the flap lift coefficient, but may cause early separation of flow. To improve the overall performance of wind turbine blades, different angular control should be used at different cross sections, in order to achieve the best performance

Strategy of Irrigation Branch in Russia

Science.gov (United States)

Zeyliger, A.; Ermolaeva, O.

2012-04-01

At this moment, at the starting time of the program on restoration of a large irrigation in Russia till 2020, the scientific and technical community of irrigation branch does not have clear vision on how to promote a development of irrigated agriculture and without repeating of mistakes having a place in the past. In many respects absence of a vision is connected to serious backlog of a scientific and technical and informational and technological level of development of domestic irrigation branch from advanced one. Namely such level of development is necessary for the resolving of new problems in new conditions of managing, and also for adequate answers to new challenges from climate and degradation of ground & water resources, as well as a rigorous requirement from an environment. In such important situation for irrigation branch when it is necessary quickly generate a scientific and technical politics for the current decade for maintenance of translation of irrigated agriculture in the Russian Federation on a new highly effective level of development, in our opinion, it is required to carry out open discussion of needs and requirements as well as a research for a adequate solutions. From political point of view a framework organized in FP6 DESIRE 037046 project is an example of good practice that can serve as methodical approach how to organize and develop such processes. From technical point of view a technology of operational management of irrigation at large scale presents a prospective alternative to the current type of management based on planning. From point of view ICT operational management demands creation of a new platform for the professional environment of activity. This platform should allow to perceive processes in real time, at their partial predictability on signals of a straight line and a feedback, within the framework of variability of decision making scenarious, at high resolution and the big ex-awning of sensor controls and the gauges

All change at the CERN UBS branch

CERN Multimedia

Antonella Del Rosso

2012-01-01

UBS branches across the country are being modernised, and the CERN branch is no exception. The Bulletin brings you a preview of the project, which will get under way in January 2013.   Mock-up of the renovated UBS branch. The changes at the UBS branch in CERN's Main Building will be no simple facelift. The entire bank will be renovated, transforming the present relatively confined premises into an open and attractive area. "The renovation of the UBS branches is part of a wider campaign designed to further enhance our customer relations," explains Ezio Mangia, the head of the CERN branch.  The UBS bank currently occupies three sets of premises in CERN's Main Building (two on the ground floor and one in the basement). "By the end of the work, which is scheduled to be completed by the middle of next year, CERN customers will benefit from a new area with open-plan counters and "hole-in-the-wall" machines accessible to...

Automated and comprehensive link engineering supporting branched, ring, and mesh network topologies

Science.gov (United States)

Farina, J.; Khomchenko, D.; Yevseyenko, D.; Meester, J.; Richter, A.

2016-02-01

Link design, while relatively easy in the past, can become quite cumbersome with complex channel plans and equipment configurations. The task of designing optical transport systems and selecting equipment is often performed by an applications or sales engineer using simple tools, such as custom Excel spreadsheets. Eventually, every individual has their own version of the spreadsheet as well as their own methodology for building the network. This approach becomes unmanageable very quickly and leads to mistakes, bending of the engineering rules and installations that do not perform as expected. We demonstrate a comprehensive planning environment, which offers an efficient approach to unify, control and expedite the design process by controlling libraries of equipment and engineering methodologies, automating the process and providing the analysis tools necessary to predict system performance throughout the system and for all channels. In addition to the placement of EDFAs and DCEs, performance analysis metrics are provided at every step of the way. Metrics that can be tracked include power, CD and OSNR, SPM, XPM, FWM and SBS. Automated routine steps assist in design aspects such as equalization, padding and gain setting for EDFAs, the placement of ROADMs and transceivers, and creating regeneration points. DWDM networks consisting of a large number of nodes and repeater huts, interconnected in linear, branched, mesh and ring network topologies, can be designed much faster when compared with conventional design methods. Using flexible templates for all major optical components, our technology-agnostic planning approach supports the constant advances in optical communications.

Prebiotic branched galacto-oligosaccharides (gos)

NARCIS (Netherlands)

Lammerts van Bueren-Brandt, Alica; Dijkhuizen, Lubbert

2018-01-01

The invention relates to galacto-oligosaccharide (GOS) compositions and the use thereof. Provided is the use of a GOS composition comprising branched and linear GOS species having a degree of polymerization (DP) of 3, wherein the branched DP3 GOS species are present in excess of linear DP3 GOS

Branching trajectory continual integral

International Nuclear Information System (INIS)

Maslov, V.P.; Chebotarev, A.M.

1980-01-01

Heuristic definition of the Feynman continual integral over branching trajectories is suggested which makes it possible to obtain in the closed form the solution of the Cauchy problem for the model Hartree equation. A number of properties of the solution is derived from an integral representation. In particular, the quasiclassical asymptotics, exact solution in the gaussian case and perturbation theory series are described. The existence theorem for the simpliest continual integral over branching trajectories is proved [ru

Flexible magnetic thin films and devices

Science.gov (United States)

Sheng, Ping; Wang, Baomin; Li, Runwei

2018-01-01

Flexible electronic devices are highly attractive for a variety of applications such as flexible circuit boards, solar cells, paper-like displays, and sensitive skin, due to their stretchable, biocompatible, light-weight, portable, and low cost properties. Due to magnetic devices being important parts of electronic devices, it is essential to study the magnetic properties of magnetic thin films and devices fabricated on flexible substrates. In this review, we mainly introduce the recent progress in flexible magnetic thin films and devices, including the study on the stress-dependent magnetic properties of magnetic thin films and devices, and controlling the properties of flexible magnetic films by stress-related multi-fields, and the design and fabrication of flexible magnetic devices. Project supported by the National Key R&D Program of China (No. 2016YFA0201102), the National Natural Science Foundation of China (Nos. 51571208, 51301191, 51525103, 11274321, 11474295, 51401230), the Youth Innovation Promotion Association of the Chinese Academy of Sciences (No. 2016270), the Key Research Program of the Chinese Academy of Sciences (No. KJZD-EW-M05), the Ningbo Major Project for Science and Technology (No. 2014B11011), the Ningbo Science and Technology Innovation Team (No. 2015B11001), and the Ningbo Natural Science Foundation (No. 2015A610110).

Human vagus nerve branching in the cervical region.

Directory of Open Access Journals (Sweden)

Niels Hammer

Full Text Available Vagus nerve stimulation is increasingly applied to treat epilepsy, psychiatric conditions and potentially chronic heart failure. After implanting vagus nerve electrodes to the cervical vagus nerve, side effects such as voice alterations and dyspnea or missing therapeutic effects are observed at different frequencies. Cervical vagus nerve branching might partly be responsible for these effects. However, vagus nerve branching has not yet been described in the context of vagus nerve stimulation.Branching of the cervical vagus nerve was investigated macroscopically in 35 body donors (66 cervical sides in the carotid sheath. After X-ray imaging for determining the vertebral levels of cervical vagus nerve branching, samples were removed to confirm histologically the nerve and to calculate cervical vagus nerve diameters and cross-sections.Cervical vagus nerve branching was observed in 29% of all cases (26% unilaterally, 3% bilaterally and proven histologically in all cases. Right-sided branching (22% was more common than left-sided branching (12% and occurred on the level of the fourth and fifth vertebra on the left and on the level of the second to fifth vertebra on the right side. Vagus nerves without branching were significantly larger than vagus nerves with branches, concerning their diameters (4.79 mm vs. 3.78 mm and cross-sections (7.24 mm2 vs. 5.28 mm2.Cervical vagus nerve branching is considerably more frequent than described previously. The side-dependent differences of vagus nerve branching may be linked to the asymmetric effects of the vagus nerve. Cervical vagus nerve branching should be taken into account when identifying main trunk of the vagus nerve for implanting electrodes to minimize potential side effects or lacking therapeutic benefits of vagus nerve stimulation.

Version control with Git

CERN Document Server

Loeliger, Jon

2012-01-01

Get up to speed on Git for tracking, branching, merging, and managing code revisions. Through a series of step-by-step tutorials, this practical guide takes you quickly from Git fundamentals to advanced techniques, and provides friendly yet rigorous advice for navigating the many functions of this open source version control system. This thoroughly revised edition also includes tips for manipulating trees, extended coverage of the reflog and stash, and a complete introduction to the GitHub repository. Git lets you manage code development in a virtually endless variety of ways, once you understand how to harness the system's flexibility. This book shows you how. Learn how to use Git for several real-world development scenarios ; Gain insight into Git's common-use cases, initial tasks, and basic functions ; Use the system for both centralized and distributed version control ; Learn how to manage merges, conflicts, patches, and diffs ; Apply advanced techniques such as rebasing, hooks, and ways to handle submodu...

Application of flexible scope in large testing laboratories

Directory of Open Access Journals (Sweden)

Carina Di Candia

2011-04-01

Full Text Available According as the international definition of Flexible Scope, a laboratory must demonstrate face with the accreditation body that it has the knowledge, experience and competence to work within the full range of its flexible scope, as well as possessing suitable laboratory environments and equipment. The laboratory must also demonstrate that it has a management system in place that can control its proposed approach while continuing to comply with the requirements of ISO 17025:2005. In case of UKAS (Unites Kingdom Accreditation Service, prior to offering accreditation for flexible scope they must have a high degree of confidence that the staff are technically competent and that the management system controlling certain key processes as development, review, validation and authorization.LATU apply these requirements since 2004 as "Unified Tests". Until this date, LATU was doing the same type of tests in different materials departments using different equipment, personal, and testing quality control. In order to that were defined cross disciplinary groups to analyze this topic approaching in personal competence and quality control tests improvement, and resource's decrease. For example, LATU has the Unified Test Tensile Strength accredited by UKAS in: corrugated and solid fiberboard, paper board, linerboard, cork plugs, plastic bags, plastic sheeting, paper, woven fabrics, plastic woven bags and woven plastic. As a result of the Unified Tests was generated a general unified manage procedure with unified criteria's, responsibilities and actions. Was written a unique testing procedure not only with the actual flexible scope and the flexibilities limits but also the compliance requirements of ISO 17025 and the accreditations body methodology. We could decrease the amount of documentation to control. Was defined the methodology and implemented periodicaly internal inter comparisons between departments in order to valid the unified tests and has a unique

Thermoelectric effects in disordered branched nanowires

Science.gov (United States)

Roslyak, Oleksiy; Piriatinskiy, Andrei

2013-03-01

We shall develop formalism of thermal and electrical transport in Si1 - x Gex and BiTe nanowires. The key feature of those nanowires is the possibility of dendrimer type branching. The branching tree can be of size comparable to the short wavelength of phonons and by far smaller than the long wavelength of conducting electrons. Hence it is expected that the branching may suppress thermal and let alone electrical conductance. We demonstrate that the morphology of branches strongly affects the electronic conductance. The effect is important to the class of materials known as thermoelectrics. The small size of the branching region makes large temperature and electrical gradients. On the other hand the smallness of the region would allow the electrical transport being ballistic. As usual for the mesoscopic systems we have to solve macroscopic (temperature) and microscopic ((electric potential, current)) equations self-consistently. Electronic conductance is studied via NEGF formalism on the irreducible electron transfer graph. We also investigate the figure of merit ZT as a measure of the suppressed electron conductance.

Adaptive fuzzy tracking control for a constrained flexible air-breathing hypersonic vehicle based on actuator compensation

Directory of Open Access Journals (Sweden)

Peng Fei Wang

2016-10-01

Full Text Available The design of an adaptive fuzzy tracking control for a flexible air-breathing hypersonic vehicle with actuator constraints is discussed. Based on functional decomposition methodology, velocity and altitude controllers are designed. Fuzzy logic systems are applied to approximate the lumped uncertainty of each subsystem of air-breathing hypersonic vehicle model. Every controllers contain only one adaptive parameter that needs to be updated online with a minimal-learning-parameter scheme. The back-stepping design is not demanded by converting the altitude subsystem into the normal output-feedback formulation, which predigests the design of a controller. The special contribution is that novel auxiliary systems are developed to compensate both the tracking errors and desired control laws, based on which the explored controller can still provide effective tracking of velocity and altitude commands when the inputs are saturated. Finally, reference trajectory tracking simulation shows the effectiveness of the proposed method in its application to air-breathing hypersonic vehicle control.

An automatic controlled apparatus of target chamber for atomic spectra and level lifetime measurements

International Nuclear Information System (INIS)

Zhao Mengchun; Yang Zhihu

1998-01-01

An automatically controlled apparatus of target chamber was made to measure spectra of the excited atoms and lifetime of the excited levels. The hardware is composed of nine parts including a computer and a step-motor, while the software consists of three branch programs. The maximum movable distance of target position is 65 cm with a step-length of 8.3 μm and a precision of +- 18 μm per 2 mm. On account of simple structure and double protection, the apparatus exhibits flexibility and reliability in years service

The role of psychological flexibility in a self-help acceptance and commitment therapy intervention for psychological distress in a randomized controlled trial.

Science.gov (United States)

Fledderus, Martine; Bohlmeijer, Ernst T; Fox, Jean-Paul; Schreurs, Karlein M G; Spinhoven, Philip

2013-03-01

This study examined the role of psychological flexibility, as a risk factor and as a process of change, in a self-help Acceptance and Commitment Therapy (ACT) intervention for adults with mild to moderate depression and anxiety. Participants were randomized to the self-help programme with e-mail support (n=250), or to a waiting list control group (n=126). All participants completed measures before and after the intervention to assess depression, anxiety and psychological flexibility. Participants in the experimental condition also completed these measures during the intervention (after three and six weeks) and at a three-month follow-up. With multilevel modelling, it was shown that the effects of the intervention on psychological distress were stronger for participants with higher levels of psychological flexibility. Furthermore, our study showed that improved psychological flexibility mediated the effects of the ACT intervention. With a cross-lagged panel design, it was shown that especially improvements in psychological flexibility in the last three sessions of the intervention were important for further reductions in anxiety. To conclude, our study showed the importance of targeting psychological flexibility during an ACT intervention for a reduction in depressive and anxiety symptoms. Copyright © 2012 Elsevier Ltd. All rights reserved.

Quantification of branching in model three-arm star polyethylene

KAUST Repository

Ramachandran, Ramnath; Beaucage, Gregory B.; Rai, Durgesh K.; Lohse, David J.; Sun, Thomas; Tsou, Andy; Norman, Alexander Iain; Hadjichristidis, Nikolaos

2012-01-01

The versatility of a novel scaling approach in quantifying the structure of model well-defined 3-arm star polyethylene molecules is presented. Many commercial polyethylenes have long side branches, and the nature and quantity of these branches varies widely among the various forms. For instance, low-density polyethylene (LDPE) is typically a highly branched structure with broad distributions in branch content, branch lengths and branch generation (in hyperbranched structures). This makes it difficult to accurately quantify the structure and the inherent structure-property relationships. To overcome this drawback, model well-defined hydrogenated polybutadiene (HPB) structures have been synthesized via anionic polymerization and hydrogenation to serve as model analogues to long-chain branched polyethylene. In this article, model 3-arm star polyethylene molecules are quantified using the scaling approach. Along with the long-chain branch content in polyethylene, the approach also provides unique measurements of long-chain branch length and hyperbranch content. Such detailed description facilitates better understanding of the effect of branching on the physical properties of polyethylene. © 2012 American Chemical Society.

Quantification of branching in model three-arm star polyethylene

KAUST Repository

Ramachandran, Ramnath

2012-01-24

The versatility of a novel scaling approach in quantifying the structure of model well-defined 3-arm star polyethylene molecules is presented. Many commercial polyethylenes have long side branches, and the nature and quantity of these branches varies widely among the various forms. For instance, low-density polyethylene (LDPE) is typically a highly branched structure with broad distributions in branch content, branch lengths and branch generation (in hyperbranched structures). This makes it difficult to accurately quantify the structure and the inherent structure-property relationships. To overcome this drawback, model well-defined hydrogenated polybutadiene (HPB) structures have been synthesized via anionic polymerization and hydrogenation to serve as model analogues to long-chain branched polyethylene. In this article, model 3-arm star polyethylene molecules are quantified using the scaling approach. Along with the long-chain branch content in polyethylene, the approach also provides unique measurements of long-chain branch length and hyperbranch content. Such detailed description facilitates better understanding of the effect of branching on the physical properties of polyethylene. © 2012 American Chemical Society.

Adaptive fiber optics collimator based on flexible hinges.

Science.gov (United States)

Zhi, Dong; Ma, Yanxing; Ma, Pengfei; Si, Lei; Wang, Xiaolin; Zhou, Pu

2014-08-20

In this manuscript, we present a new design for an adaptive fiber optics collimator (AFOC) based on flexible hinges by using piezoelectric stacks actuators for X-Y displacement. Different from traditional AFOC, the new structure is based on flexible hinges to drive the fiber end cap instead of naked fiber. We fabricated a real AFOC based on flexible hinges, and the end cap's deviation and resonance frequency of the device were measured. Experimental results show that this new AFOC can provide fast control of tip-tilt deviation of the laser beam emitting from the end cap. As a result, the fiber end cap can support much higher power than naked fiber, which makes the new structure ideal for tip-tilt controlling in a high-power fiber laser system.

Solution Coating of Superior Large-Area Flexible Perovskite Thin Films with Controlled Crystal Packing

KAUST Repository

Li, Jianbo

2017-05-08

Solution coating of organohalide lead perovskites offers great potential for achieving low-cost manufacturing of large-area flexible optoelectronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of crystal packing. Herein, this study reports using solution shearing to confine crystal nucleation and growth in large-area printed MAPbI3 thin films. Near single-crystalline perovskite microarrays are demonstrated with a high degree of controlled macroscopic alignment and crystal orientation, which exhibit significant improvements in optical and optoelectronic properties comparing with their random counterparts, spherulitic, and nanograined films. In particular, photodetectors based on the confined films showing intense anisotropy in charge transport are fabricated, and the device exhibits significantly improved performance in all aspects by one more orders of magnitude relative to their random counterparts. It is anticipated that perovskite films with controlled crystal packing may find applications in high-performance, large-area printed optoelectronics, and solar cells.

Solution Coating of Superior Large-Area Flexible Perovskite Thin Films with Controlled Crystal Packing

KAUST Repository

Li, Jianbo; Liu, Yucheng; Ren, Xiaodong; Yang, Zhou; Li, Ruipeng; Su, Hang; Yang, Xiaoming; Xu, Junzhuo; Xu, Hua; Hu, Jian-Yong; Amassian, Aram; Zhao, Kui; Liu, Shengzhong Frank

2017-01-01

Solution coating of organohalide lead perovskites offers great potential for achieving low-cost manufacturing of large-area flexible optoelectronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of crystal packing. Herein, this study reports using solution shearing to confine crystal nucleation and growth in large-area printed MAPbI3 thin films. Near single-crystalline perovskite microarrays are demonstrated with a high degree of controlled macroscopic alignment and crystal orientation, which exhibit significant improvements in optical and optoelectronic properties comparing with their random counterparts, spherulitic, and nanograined films. In particular, photodetectors based on the confined films showing intense anisotropy in charge transport are fabricated, and the device exhibits significantly improved performance in all aspects by one more orders of magnitude relative to their random counterparts. It is anticipated that perovskite films with controlled crystal packing may find applications in high-performance, large-area printed optoelectronics, and solar cells.

Bi-objective branch-and-cut algorithms

DEFF Research Database (Denmark)

Gadegaard, Sune Lauth; Ehrgott, Matthias; Nielsen, Lars Relund

Most real-world optimization problems are of a multi-objective nature, involving objectives which are conflicting and incomparable. Solving a multi-objective optimization problem requires a method which can generate the set of rational compromises between the objectives. In this paper, we propose...... are strengthened by cutting planes. In addition, we suggest an extension of the branching strategy "Pareto branching''. Extensive computational results obtained for the bi-objective single source capacitated facility location problem prove the effectiveness of the algorithms....... and compares it to an upper bound set. The implicit bound set based algorithm, on the other hand, fathoms branching nodes by generating a single point on the lower bound set for each local nadir point. We outline several approaches for fathoming branching nodes and we propose an updating scheme for the lower...

Geology of the Cane Branch and Helton Branch watershed areas, McCreary County, Kentucky

Science.gov (United States)

Lyons, Erwin J.

1957-01-01

Cane Branch and Helton Branch in McCreary County, Kentucky, are about 1.4 miles apart (fig. 1). Can Branch, which is about 2.1 miles long, emptied into Hughes Fork of Beaver Creek. Its watershed area of about 1.5 square miles lies largely in the Wiborf 7 1/2-minute quadrangle (SW/4 Cumberland Falls 15-minute quadrangle), but the downstream part of the area extends northward into the Hail 7 1/2-minute quadrangle (NW/4 Cumberland Falls 15-minute quadrangle). Helton Branch, which is about 1.1 miles long, has two tributaries and empties into Little Hurricane Fork of Beaver Creek. It drains an area of about 0.8 square mile of while about 0.5 square mile is in the Hail quadrangle and the remainder in the Wilborg quadrangle. The total relief in the Can Branch area is about 500 feet and in the Helton Branch area about 400 feet. Narrow, steep-sided to canyon-like valley and winding ridges, typical of the Pottsville escarpment region, are characteristic of both areas. Thick woods and dense undergrowth cover much of the two areas. Field mapping was done on U.S. Geological Survey 7 1/2-minute maps having a scale of 1:24,000 and a contour interval of 20 feet. Elevations of lithologic contacts were determined with a barometer and a hand level. Aerial photographs were used principally to trace the cliffs formed by sandstone and conglomerate ledges. Exposures, except for those of the cliff- and ledge-forming sandstone and conglomerates, are not abundant. The most complete stratigraphic sections (secs. 3 and 4, fig. 2) in the two areas are exposed in cuts of newly completed Forest Service roads, but the rick in the upper parts of the exposures is weathered. To supplement these sections, additional sections were measured in cuts along the railroad and main highways in nor near the watersheds.

Physiological pulmonary branch stenosis in newborns: 2D-echocardiographic and Doppler characteristics and 4 months follow up

Directory of Open Access Journals (Sweden)

Amer Yazdanparast

2004-02-01

Full Text Available Transient systolic murmurs in neonates and premature infants due to mild left (LPA and right (RPA pulmonary branch stenosis is recognized but follow up studies are lacking. A total of 32 neonates with murmur and 32 controls were evaluated echocardiographically at baseline and in four months follow up. Diameters of LPA and RPA were smaller in patients with murmur. Colour-coded Doppler showed turbulent flow in LPA and RPA in 93% of patients and flow velocities of both pulmonary branches were significantly higher than in controls. The follow up study at 4 months showed absent (23% or decreased murmur (76%. Echocardiographically, absolute and relative diameters of LPA and RPA increased whereas the ratio of main pulmonary artery/aorta did not change suggesting accelerated growth or dilatation of the pulmonary branches. Thus, transient systolic murmurs in neonates are associated with temporary relative hypoplasia of the pulmonary branches which showed increased growth leading to disappearance of the murmur in most cases within 4 months of life.

The effect of 60Co γ-rays irradiation on seeds and branches of Euonymus fortunei

International Nuclear Information System (INIS)

Ao Yan; Inner Mongolia Agriculture Univ., Huhhot; Zhang Guosheng; Lu Renqiang; Pan Qinghua

2006-01-01

Seeds and plant branches of Euonymus fortunei were irradiated with 60 Co γ-ray. The results showed that after irradiation, seed germination rate, emergence rate and surviving rate were restrained, and it was negatively correlated with irradiation dose increasing significantly. The first euphylis period was delayed compared with control. Seedling height decreased with the increase of irradiation dose. Semi-lethal dose of Euonymus fortunei seeds was 128.56 Gy. Branch irradiation could cause significantly number and length reduced, and it is correlated with irradiation dose increasing. The semi-lethal dose for Euonymus fortunei branches was 95.54 Gy. (authors)

Action of a diffusible target-derived chemoattractant on cortical axon branch induction and directed growth.

Science.gov (United States)

Sato, M; Lopez-Mascaraque, L; Heffner, C D; O'Leary, D D

1994-10-01

Cortical axons innervate their brainstem target, the basilar pons, by the initiation and extension of collateral branches interstitially along their length. To address whether a diffusible pons-derived chemoattractant controls these events, we used cocultures in collagen matrices and time-lapse microscopy. Pontine explants enhanced by 5-fold the de novo initiation of transient branches along cortical axons; most branches were directed toward pons. Of the branches extended toward pons, 2%-3% were stabilized; those extended away were not. Pontine explants also enhanced the stable bifurcation of growth cones and prompted directional changes by growth cone turning and collateral extension. These effects were distance dependent and mimicked by pons-conditioned medium. This evidence indicates that the pons activity promotes branch initiation interstitially along cortical axons, a novel property for a chemoattractant, and provides a directional cue for their growth. These findings suggest that the pons chemoattractant serves as a diffusible target-recognition molecule.

3rd Workshop on Branching Processes and their Applications

CERN Document Server

González, Miguel; Gutiérrez, Cristina; Martínez, Rodrigo; Minuesa, Carmen; Molina, Manuel; Mota, Manuel; Ramos, Alfonso; WBPA15

2016-01-01

This volume gathers papers originally presented at the 3rd Workshop on Branching Processes and their Applications (WBPA15), which was held from 7 to 10 April 2015 in Badajoz, Spain (http://branching.unex.es/wbpa15/index.htm). The papers address a broad range of theoretical and practical aspects of branching process theory. Further, they amply demonstrate that the theoretical research in this area remains vital and topical, as well as the relevance of branching concepts in the development of theoretical approaches to solving new problems in applied fields such as Epidemiology, Biology, Genetics, and, of course, Population Dynamics. The topics covered can broadly be classified into the following areas: 1. Coalescent Branching Processes 2. Branching Random Walks 3. Population Growth Models in Varying and Random Environments 4. Size/Density/Resource-Dependent Branching Models 5. Age-Dependent Branching Models 6. Special Branching Models 7. Applications in Epidemiology 8. Applications in Biology and Genetics Offer...

Control of 2D Flexible Structures by Confinement of Vibrations and Regulation of Their Energy Flow

Directory of Open Access Journals (Sweden)

Fakhreddine Landolsi

2009-01-01

Full Text Available In this paper, we investigate the control of 2D flexible structures by vibration confinement and the regulation of their energy flow along prespecified spatial paths. A discretized-model-based feedback strategy, aiming at confining and suppressing simultaneously the vibration, is proposed. It is assumed that the structure consists of parts that are sensitive to vibrations. The control design introduces a new pseudo-modal matrix derived from the computed eigenvectors of the discretized model. Simulations are presented to show the efficacy of the proposed control law. A parametric study is carried out to examine the effects of the different control parameters on the simultaneous confinement and suppression of vibrations. In addition, we conducted a set of simulations to investigate the flow control of vibrational energy during the confinement-suppression process. We found that the energy flow can be regulated via a set of control parameters for different confinement configurations.

Synthesis and characterization of branched fcc/hcp ruthenium nanostructures and their catalytic activity in ammonia borane hydrolysis

KAUST Repository

AlYami, Noktan

2018-01-30

Several systems have shown the ability to stabilize uncommon crystal structures during the synthesis of metallic nanoparticles. By tailoring the nanoparticle crystal structure, the physical and chemical properties of the particles can also be controlled. Herein, we first synthesized branched nanoparticles of mixed hcp/fcc ruthenium, which were formed using tungsten carbonyl [W(CO)6] as both a reducing agent and a source of carbon monoxide. The branched particles were formed from multiple particulates off a central core. High-resolution transmission electron microscopy (HRTEM) clearly showed that the branched structures consisted of aligned hcp crystal domains, a mixture of fcc and hcp crystal domains with several defects and misalignments, and particles that contained multiple cores and branches. Branched particles were also formed with molybdenum carbonyl [Mo(CO)6], and faceted particles of hcp and fcc particles were formed with Re2(CO)10 as a carbon monoxide source. Without metal carbonyls, small particles of spherical hcp ruthenium were produced, and their size could be controlled by the selection of the precursor. The ruthenium nanoparticles were tested for ammonia borane hydrolysis; the branched nanoparticles were more reactive for catalytic hydrogen evolution than the faceted hcp/fcc nanoparticles or the spherical hcp nanoparticles. This work showcases the potential of crystal phase engineering of transition metal nanoparticles by different carbon monoxide precursors for tailoring their catalytic reactivity.

Light-controlling, flexible and transparent ethanol gas sensor based on ZnO nanoparticles for wearable devices.

Science.gov (United States)

Zheng, Z Q; Yao, J D; Wang, B; Yang, G W

2015-06-16

In recent years, owing to the significant applications of health monitoring, wearable electronic devices such as smart watches, smart glass and wearable cameras have been growing rapidly. Gas sensor is an important part of wearable electronic devices for detecting pollutant, toxic, and combustible gases. However, in order to apply to wearable electronic devices, the gas sensor needs flexible, transparent, and working at room temperature, which are not available for traditional gas sensors. Here, we for the first time fabricate a light-controlling, flexible, transparent, and working at room-temperature ethanol gas sensor by using commercial ZnO nanoparticles. The fabricated sensor not only exhibits fast and excellent photoresponse, but also shows high sensing response to ethanol under UV irradiation. Meanwhile, its transmittance exceeds 62% in the visible spectral range, and the sensing performance keeps the same even bent it at a curvature angle of 90(o). Additionally, using commercial ZnO nanoparticles provides a facile and low-cost route to fabricate wearable electronic devices.

Simple feed-forward active control method for suppressing the shock response of a flexible cantilever beam

International Nuclear Information System (INIS)

Shin, Kihong; Pyo, Sangho; Lee, Young-Sup

2009-01-01

In this paper a 'simple' active control method (without using an error sensor and an adaptive algorithm) is proposed for reducing the residual vibration of a flexible cantilever beam excited by a shock impulse. It is assumed that the shock input can be measured and always occurs on the same point of the beam. In this case, it is shown that a much simpler active control strategy than conventional methods can be used if the system is well identified. The proposed method is verified experimentally with consideration of some practical aspects: the control performance with respect to the control point in time and the choice of frequency response function (FRF) estimators to cope with measurement noise. Experimental results show that a large attenuation of the residual vibration can be achieved using the proposed method. (technical note)

Novel prescribed performance neural control of a flexible air-breathing hypersonic vehicle with unknown initial errors.

Science.gov (United States)

Bu, Xiangwei; Wu, Xiaoyan; Zhu, Fujing; Huang, Jiaqi; Ma, Zhen; Zhang, Rui

2015-11-01

A novel prescribed performance neural controller with unknown initial errors is addressed for the longitudinal dynamic model of a flexible air-breathing hypersonic vehicle (FAHV) subject to parametric uncertainties. Different from traditional prescribed performance control (PPC) requiring that the initial errors have to be known accurately, this paper investigates the tracking control without accurate initial errors via exploiting a new performance function. A combined neural back-stepping and minimal learning parameter (MLP) technology is employed for exploring a prescribed performance controller that provides robust tracking of velocity and altitude reference trajectories. The highlight is that the transient performance of velocity and altitude tracking errors is satisfactory and the computational load of neural approximation is low. Finally, numerical simulation results from a nonlinear FAHV model demonstrate the efficacy of the proposed strategy. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Flexible benefits plans. Perceptions of their effectiveness.

Science.gov (United States)

Agho, A O

1995-01-01

Flexible benefits plans have been used in businesses since the 1970s to control healthcare costs and meet the needs of an increasingly diverse work force. More recently, healthcare organizations have begun to implement the flexible benefits concept. This study collected data from human resources executives at hospitals with and without flex plans to investigate how they perceive the effectiveness of and the problems associated with such plans.

Increasing flexibility of coal power plant by control system modifications

Directory of Open Access Journals (Sweden)

Marušić Ante

2016-01-01

Full Text Available Expanding implementation of intermittent renewable energy sources has already started to change the role of thermal power plants in energy systems across Europe. Traditionally base load plants are now forced to operate as peaking plants. A familiar transition in upcoming years is expected in Croatia and coal power plant operators are preparing accordingly. To evaluate cycling capabilities and control system operation for flexible operation of selected 210 MW coal plant, series of tests with different load gradients were performed and results were thoroughly analyzed. Two possible “bottlenecks” are identified, thermal stress in superheater header, and achievable ramping rate considering operational limitations of coal feeders, firing system and evaporator dynamics. Several unexpected readings were observed, usually caused by malfunctioning sensors and equipment, resulting in unexpected oscillations of superheated steam temperature. Based on superheater geometry and experimental data, maximal steam temperature gradient during ramping was evaluated. Since thermal stress was well inside the safety margins, the simulation model of the whole boiler was used to evaluate achievable ramping on electric side.

Coulomb branches with complex singularities

Science.gov (United States)

Argyres, Philip C.; Martone, Mario

2018-06-01

We construct 4d superconformal field theories (SCFTs) whose Coulomb branches have singular complex structures. This implies, in particular, that their Coulomb branch coordinate rings are not freely generated. Our construction also gives examples of distinct SCFTs which have identical moduli space (Coulomb, Higgs, and mixed branch) geometries. These SCFTs thus provide an interesting arena in which to test the relationship between moduli space geometries and conformal field theory data. We construct these SCFTs by gauging certain discrete global symmetries of N = 4 superYang-Mills (sYM) theories. In the simplest cases, these discrete symmetries are outer automorphisms of the sYM gauge group, and so these theories have lagrangian descriptions as N = 4 sYM theories with disconnected gauge groups.

Flexible Demand Control to Enhance the Dynamic Operation of Low Voltage Networks

DEFF Research Database (Denmark)

Diaz de Cerio Mendaza, Iker; Szczesny, Ireneusz Grzegorz; Pillai, Jayakrishnan Radhakrishna

2015-01-01

Moving towards a carbon free energy system has become an objective for many countries nowadays. Among other changes, the electrification of strategic sectors such as heating and transportation is inevitable. As a consequence, the current power system load will substantially increase...... for controlling the demand response of a low voltage grid. This is designed to; i) maximize the grid utilization, thereby reducing the need for reinforcement, ii) accommodate the maximum number of flexible loads and iii) satisfy the power and comfort requirements from each of the consumers in the network....... In this context, the nature of the expected loads (heat pumps, plug-in electric vehicles, etc.) makes the low voltage networks specially targeted. A promising solution to overcome the challenges resulting from their grid integration, is demand response. This paper introduces a hierarchical structure...

On flexibility

OpenAIRE

Weiss, Christoph R.; Briglauer, Wolfgang

2000-01-01

By building on theoretical work by Mills and Schumann (1985) and Ungern-Sternberg (1990) this paper provides evidence on the determinants of two dimensions of flexibility, the flexibility in adjusting aggregate output over time (tactical flexibility) as well as the ability to switch quickly between products (operational flexibility). Econometric analysis of a sample of 40.000 farms in Upper-Austria for the period 1980 to 1990 suggests that larger full-time farms operated by younger, better ed...

Conformations and solution properties of star-branched polyelectrolytes

NARCIS (Netherlands)

Borisov, O.V.; Zhulina, E.B.; Leermakers, F.A.M.; Ballauff, M.; Muller, A.H.E.

2011-01-01

Aqueous solutions of star-like polyelectrolytes (PEs) exhibit distinctive features that originate from the topological complexity of branched macromolecules. In a salt-free solution of branched PEs, mobile counterions preferentially localize in the intramolecular volume of branched macroions.

Design and fabrication of magnetically functionalized flexible micropillar arrays for rapid and controllable microfluidic mixing

KAUST Repository

Zhou, BingPu

2015-03-25

Magnetically functionalized PDMS-based micropillar arrays have been successfully designed, fabricated and implanted for controllable microfluidic mixing. The arrangement of PDMS micropillar arrays inside the microchannel can be flexibly controlled by an external magnetic field. As a consequence, the flow fields inside the microchannel can be regulated at will via magnetic activation conveniently. When a microchannel is implanted with such micropillar arrays, two microstreams can be mixed easily and controllably upon the simple application of an on/off magnetic signal. Mixing efficiencies based on micropillar arrays with different densities were investigated and compared. It was found that micropillar arrays with higher density (i.e. smaller pillar pitch) would render better mixing performance. Our microfluidic system is capable of generating highly reproducible results within many cycles of mixing/non-mixing conversion. We believe that the simple mixing-triggering method together with rapid and controllable mixing control will be extraordinarily valuable for various biological or chemical applications in the future. This journal is © The Royal Society of Chemistry 2015.

Design and fabrication of magnetically functionalized flexible micropillar arrays for rapid and controllable microfluidic mixing

KAUST Repository

Zhou, BingPu; Xu, Wei; Syed, Ahad; Chau, Yeungyeung; Chen, Longqing; Chew, Basil; Yassine, Omar; Wu, Xiaoxiao; Gao, Yibo; Zhang, Jingxian; Xiao, Xiao; Kosel, Jü rgen; Zhang, Xixiang; Yao, Zhaohui; Wen, Weijia

2015-01-01

Magnetically functionalized PDMS-based micropillar arrays have been successfully designed, fabricated and implanted for controllable microfluidic mixing. The arrangement of PDMS micropillar arrays inside the microchannel can be flexibly controlled by an external magnetic field. As a consequence, the flow fields inside the microchannel can be regulated at will via magnetic activation conveniently. When a microchannel is implanted with such micropillar arrays, two microstreams can be mixed easily and controllably upon the simple application of an on/off magnetic signal. Mixing efficiencies based on micropillar arrays with different densities were investigated and compared. It was found that micropillar arrays with higher density (i.e. smaller pillar pitch) would render better mixing performance. Our microfluidic system is capable of generating highly reproducible results within many cycles of mixing/non-mixing conversion. We believe that the simple mixing-triggering method together with rapid and controllable mixing control will be extraordinarily valuable for various biological or chemical applications in the future. This journal is © The Royal Society of Chemistry 2015.

Control over structure-specific flexibility improves anatomical accuracy for point-based deformable registration in bladder cancer radiotherapy.

Science.gov (United States)

Wognum, S; Bondar, L; Zolnay, A G; Chai, X; Hulshof, M C C M; Hoogeman, M S; Bel, A

2013-02-01

Future developments in image guided adaptive radiotherapy (IGART) for bladder cancer require accurate deformable image registration techniques for the precise assessment of tumor and bladder motion and deformation that occur as a result of large bladder volume changes during the course of radiotherapy treatment. The aim was to employ an extended version of a point-based deformable registration algorithm that allows control over tissue-specific flexibility in combination with the authors' unique patient dataset, in order to overcome two major challenges of bladder cancer registration, i.e., the difficulty in accounting for the difference in flexibility between the bladder wall and tumor and the lack of visible anatomical landmarks for validation. The registration algorithm used in the current study is an extension of the symmetric-thin plate splines-robust point matching (S-TPS-RPM) algorithm, a symmetric feature-based registration method. The S-TPS-RPM algorithm has been previously extended to allow control over the degree of flexibility of different structures via a weight parameter. The extended weighted S-TPS-RPM algorithm was tested and validated on CT data (planning- and four to five repeat-CTs) of five urinary bladder cancer patients who received lipiodol injections before radiotherapy. The performance of the weighted S-TPS-RPM method, applied to bladder and tumor structures simultaneously, was compared with a previous version of the S-TPS-RPM algorithm applied to bladder wall structure alone and with a simultaneous nonweighted S-TPS-RPM registration of the bladder and tumor structures. Performance was assessed in terms of anatomical and geometric accuracy. The anatomical accuracy was calculated as the residual distance error (RDE) of the lipiodol markers and the geometric accuracy was determined by the surface distance, surface coverage, and inverse consistency errors. Optimal parameter values for the flexibility and bladder weight parameters were determined

Control over structure-specific flexibility improves anatomical accuracy for point-based deformable registration in bladder cancer radiotherapy