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Sample records for brushed dc motor

  1. Development of the Upgraded DC Brush Gear Motor for Spacebus Platforms

    Science.gov (United States)

    Berning, Robert H.; Viout, Olivier

    2010-01-01

    The obsolescence of materials and processes used in the manufacture of traditional DC brush gear motors has necessitated the development of an upgraded DC brush gear motor (UBGM). The current traditional DC brush gear motor (BGM) design was evaluated using Six-Sigma process to identify potential design and production process improvements. The development effort resulted in a qualified UBGM design which improved manufacturability and reduced production costs. Using Six-Sigma processes and incorporating lessons learned during the development process also improved motor performance for UBGM making it a more viable option for future use as a deployment mechanism in space flight applications.

  2. Implementation of Brushed DC Motor Control in LabVIEW FPGA

    Directory of Open Access Journals (Sweden)

    K. Lamár

    2013-12-01

    Full Text Available The paper introduces the fundamentals of motor control. It explains the basic equations and introduces the control diagram of the brushed DC motor. It introduces the four quadrant DC chopper circuit and the basic methods to operate it. After that, it explains the fundamentals of the current control of DC motors and its two basic methods: the pulse width modulation and the hysteresis current control. Finally it gives a short example of the practical implementation of the hysteresis current controller for the four quadrant DC chopper in LabVIEW FPGA.

  3. A Novel Method for Sensorless Speed Detection of Brushed DC Motors

    Directory of Open Access Journals (Sweden)

    Ernesto Vazquez-Sanchez

    2016-12-01

    Full Text Available Many motor applications require accurate speed measurement. For brushed dc motors, speed can be measured with conventional observers or sensorless observers. Sensorless observers have the advantage of not requiring any external devices to be attached to the motor. Instead, voltage and/or current are measured and used to estimate the speed. The sensorless observers are usually divided into two groups: those based on the dynamic model, and those based on the ripple component. This paper proposes a method that measures the current of brushed dc motors and analyses the position of its spectral components. From these spectral components, the method estimates the motor speed. Three tests, performed each with the speeds ranging from 2000 to 3000 rpm either at constant-speed, at slowly changing speeds, or at rapidly changing speeds, showed that the average error was below 1 rpm and that the deviation error was below 1.5 rpm. The proposed method: (i is a novel method that is not based on either the dynamic model or on the ripple component; (ii requires only the measurement of the current for the speed estimation; (iii can be used for brushed dc (direct current motors with a large number of coils; and (iv achieves a low error in the speed estimation.

  4. Characterization of Small DC Brushed and Brushless Motors

    Science.gov (United States)

    2013-03-01

    back EMF signals for a brushless motor. ............................13 Figure 11. Torque vs. RPM at various voltages, 100% throttle for an A05-3700...electrical power to mechanical power in the form of rotary motion. This electromechanical system is characterized by a few specific parameters that, if...of the magnets over the coils also creates a back electromotive force ( EMF ) on the unenergized stator, which is sensed by the speed controller to

  5. Brushed permanent magnet DC MLC motor operation in an external magnetic field.

    Science.gov (United States)

    Yun, J; St Aubin, J; Rathee, S; Fallone, B G

    2010-05-01

    Linac-MR systems for real-time image-guided radiotherapy will utilize the multileaf collimators (MLCs) to perform conformal radiotherapy and tumor tracking. The MLCs would be exposed to the external fringe magnetic fields of the linac-MR hybrid systems. Therefore, an experimental investigation of the effect of an external magnetic field on the brushed permanent magnet DC motors used in some MLC systems was performed. The changes in motor speed and current were measured for varying external magnetic field strengths up to 2000 G generated by an EEV electromagnet. These changes in motor characteristics were measured for three orientations of the motor in the external magnetic field, mimicking changes in motor orientations due to installation and/or collimator rotations. In addition, the functionality of the associated magnetic motor encoder was tested. The tested motors are used with the Varian 120 leaf Millennium MLC (Maxon Motor half leaf and full leaf motors) and the Varian 52 leaf MKII MLC (MicroMo Electronics leaf motor) including a carriage motor (MicroMo Electronics). In most cases, the magnetic encoder of the motors failed prior to any damage to the gearbox or the permanent magnet motor itself. This sets an upper limit of the external magnetic field strength on the motor function. The measured limits of the external magnetic fields were found to vary by the motor type. The leaf motor used with a Varian 52 leaf MKII MLC system tolerated up to 450 +/- 10 G. The carriage motor tolerated up to 2000 +/- 10 G field. The motors used with the Varian 120 leaf Millennium MLC system were found to tolerate a maximum of 600 +/- 10 G. The current Varian MLC system motors can be used for real-time image-guided radiotherapy coupled to a linac-MR system, provided the fringe magnetic fields at their locations are below the determined tolerance levels. With the fringe magnetic fields of linac-MR systems expected to be larger than the tolerance levels determined, some form of

  6. Teaching about operation of brushless DC motors

    OpenAIRE

    Čufar, Aleksandra

    2013-01-01

    Brush DC motor is being replaced by brushless DC motors on every area of application. My diploma thesis is a presentation of brushless DC motor, how it works and its application. Within first part we describe various electric motors and their application. There are several types of electric motors division. Last to be added is a brushless motor. Within second part of thesis we look into a brushless DC motor, how it works, its application and control. In the third part of thesis we construct a...

  7. Features of Running Brush Motors in Dry Nitrogen Environment When Using in Electrohydraulic Actuators

    Directory of Open Access Journals (Sweden)

    Y. A. Petrov

    2014-01-01

    Full Text Available The work concerns the constructive characteristics optimization of brushless D.C. (direct current motors used in electromechanical spacecraft drives.The spacecraft electromechanical drives and units use rather widely the brushless D.C. motors in which a motor commutator is replaced with more reliable semiconductor commutator controlled by the rotor position sensors. However, these motors are of low power.Electrohydraulic actuators (EHA use simple permanent-magnet motors (PMM of rather high power and commutator motors with graphite brush variable contacts.High reliability of brush motors, and, therefore a reliability of EHA in general, substantially depends on the quality of motor commutator operation. There are different reasons for a possible impact on the normal motor commutator operation. One of them is brush wear. Sparking brushes and burning commutator bars are possible in case brushes are poorly grinded to fit, brushes cannot freely move true in the brush holder box, and in case an incorrect force to clamp brushes to the commutator is chosen.It is established that drive wear resistance and operability depends on the gas environment composition being under sealed motor housing. In dry nitrogen environment brush wear suddenly raises because of the changing tribological performances of the commutator thus leading to essentially falling isolation resistance and no motor start.It is recommended to fill a space under sealed motor housing with air. Positive experience of operating spacecraft device containers with mobile electromechanical couples allowed us to find that in this case a dew point of filled air must be minus 20˚C.The paper offers an electromechanical alternative of design to the electrohydraulic actuators, with a ball-screw gear of the actuation mechanism, possessing a number of advantages.

  8. Numerical simulation of motor brush dynamic behavior; Motor brush kyodo no simulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Takasaki, K.; Yokota, M.; Ishii, T.; Kizuka, K.; Ina, K. [Calsonic Corp., Tokyo (Japan)

    1998-05-01

    A model that simulates automobile motor brush behavior is introduced, constructed with the aid of an ADAMS (Automatic Dynamic Analysis of Mechanical Systems) software program. The basic model is a commutation section consisting of a brush, holder, presser spring, and a commutator. The external forces imposed on the brush include the spring pressure on the brush, the impingement of commutator slits on the brush, the repulsion by and friction with the commutator segments, and the repulsion by and friction with the holder, and each of them is worked out by calculation. An experiment is performed to verify the appropriateness of the simulation and findings are collected, some of which are outlined below. The waveforms of oscillating acceleration on the real-time basis at a point on a commutator rotating at 1000rpm contains impingements of commutator slits occurring at intervals of 5 milliseconds and stabilization returning after approximately 3 oscillations after each impingement, and this is confirmed by the outcome of the experiment. The result of calculation performed on the real-time basis for the lateral and longitudinal oscillating acceleration on the brush with the rotor running at the same speed agrees roughly with the outcome of the experiment. 12 refs., 7 figs.

  9. Motor control for a brushless DC motor

    Science.gov (United States)

    Peterson, William J. (Inventor); Faulkner, Dennis T. (Inventor)

    1985-01-01

    This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.

  10. Summary of electric vehicle dc motor-controller tests

    Energy Technology Data Exchange (ETDEWEB)

    McBrien, E F; Tryon, H B

    1982-09-01

    Available performance data for production motors are usually of marginal value to the electric vehicle designer. To provide at least a partial remedy to this situation, tests of typical dc propulsion motors and controllers were conducted as part of the DOE Electric Vehicle Program. The objectives of this program were to evaluate the differences in the performance of dc motors when operating with chopper-type controllers and when operating on direct current; and to gain an understanding of the interactions between the motor and the controller which cause these differences. Toward this end, motor-controller tests performed by the NASA Lewis Research Center provided some of the first published data that quantified motor efficiency variations for both ripple-free (straight dc) and chopper modes of operation. Test and analysis work at the University of Pittsburgh explored motor-controller relationships in greater depth. And to provide additional data, 3E Vehicles tested two small motors, both on a dynamometer and in a vehicle, and the Eaton Corporation tested larger motors, using sophisticated instrumentation and digital processing techniques. All the motors tested were direct-current types. Of the separately excited types, seven were series wound and two were shunt wound. One self-excited permanent magnet type was also tested. Four of the series wound motors used brush shifting to obtain good commutation. In almost all cases, controller limitations constrained the test envelope so that the full capability of the motors could not be explored.

  11. Tachometers Derived From a Brushless DC Motor

    Science.gov (United States)

    Howard, David E.; Smith, Dennis A.

    2007-01-01

    The upper part of the figure illustrates the major functional blocks of a direction-sensitive analog tachometer circuit based on the use of an unexcited two-phase brushless dc motor as a rotation transducer. The primary advantages of this circuit over many older tachometer circuits include the following: Its output inherently varies linearly with the rate of rotation of the shaft. Unlike some tachometer circuits that rely on differentiation of voltages with respect to time, this circuit relies on integration, which results in signals that are less noisy. There is no need for an additional shaft-angle sensor, nor is there any need to supply electrical excitation to a shaft-angle sensor. There is no need for mechanical brushes (which tend to act as sources of electrical noise). The underlying concept and electrical design are relatively simple. This circuit processes the back-electromagnetic force (back-emf) outputs of the two motor phases into a voltage directly proportional to the instantaneous rate (sign magnitude) of rotation of the shaft. The processing in this circuit effects a straightforward combination of mathematical operations leading to a final operation based on the well-known trigonometric identity (sin x)2 + (cos x)2 = 1 for any value of x. The principle of operation of this circuit is closely related to that of the tachometer circuit described in Tachometer Derived From Brushless Shaft-Angle Resolver (MFS-28845), NASA Tech Briefs, Vol. 19, No. 3 (March 1995), page 39. However, the present circuit is simpler in some respects because there is no need for sinusoidal excitation of shaftangle- resolver windings.

  12. Independent Review Support for Phoenix Mars Mission Robotic Arm Brush Motor Failure

    Science.gov (United States)

    McManamen, John P.; Pellicciotti, Joseph; DeKramer, Cornelis; Dube, Michael J.; Peeler, Deborah; Muirhead, Brian K.; Sevilla, Donald R.; Sabahi, Dara; Knopp, Michael D.

    2007-01-01

    The Phoenix Project requested the NASA Engineering and Safety Center (NESC) perform an independent peer review of the Robotic Arm (RA) Direct Current (DC) motor brush anomalies that originated during the Mars Exploration Rover (MER) Project and recurred during the Phoenix Project. The request was to evaluate the Phoenix Project investigation efforts and provide an independent risk assessment. This includes a recommendation for additional work and assessment of the flight worthiness of the RA DC motors. Based on the investigation and findings contained within this report, the IRT concurs with the risk assessment Failure Cause / Corrective Action (FC/CA) by the project, "Failure Effect Rating "3"; Major Degradation or Total Loss of Function, Failure Cause/Corrective Action Rating Currently "4"; Unknown Cause, Uncertainty in Corrective Action."

  13. Pemodelan Sistem Kontrol Motor DC Dengan Temperatur Udara Sebagai Pemicu

    OpenAIRE

    Prabowo, Brilliant Adhi

    2008-01-01

    Motor dc lebih sering digunakan untuk beberapa kegiatan yang memerlukan pengaturan kecepatan daripada motor ac. Disamping pengontrolan kecepatan putar, sistem control motor dc juga mengatur arah putar rotor, searah jarum jam atau berlawanan dengan arah jarum jam. Salah satu sistem control motor dc adalah menggunakan Modulasi Lebar Pulsa (PWM) sebagai pemicu pada driver control seperti transistor H-Bridge. Penelitian ini bertujuan untuk merancang sistem control motor dc menggunakan suhu udar...

  14. Modeling and simulation for micro DC motor based on simulink

    Science.gov (United States)

    Shen, Hanxin; Lei, Qiao; Chen, Wenxiang

    2017-09-01

    The micro DC motor has a large market demand but there is a lack of theoretical research for it. Through detailed analysis of the commutation process of micro DC motor commutator, based on micro DC motor electromagnetic torque equation and mechanical torque equation, with the help of Simulink toolkit, a triangle connection micro DC motor simulation model is established. By using the model, a sample micro DC motor are simulated, and an experimental measurements has been carried on the sample micro DC motor. It is found that the simulation results are consistent with theoretical analysis and experimental results.

  15. Brushless dc motor uses electron beam switching tube as commutator

    Science.gov (United States)

    Studer, P.

    1965-01-01

    Electron beam switching tube eliminates physical contact between rotor and stator in brushless dc motor. The tube and associated circuitry control the output of a dc source to sequentially energize the motor stator windings.

  16. Embedded Based DC Motor Speed Control System

    Directory of Open Access Journals (Sweden)

    Chandrasekhar T.

    2010-10-01

    Full Text Available An embedded based DC motor speed control system using cygnal microcontroller (C8051F020 has been designed and developed. It is based on frequency domain technique. The principle is opto-coupler senses the speed of the motor in the form of TTL pulses, which is given to F/V (frequency to voltage converter. The output of the F/V converter voltage is fed to an inbuilt 12-bit ADC of cygnal microcontroller. The converted digital value applied in Liner equitation for converting back to frequency and speed is displayed on two lines LCD in RPM. Microcontroller is applied for PID control action to correct error in the form of voltage to the motor through built-in 12-bit D/A converter, PWM circuit, and actuator. The present study discusses the design, development, fabrication, and analysis of cygnal microcontroller based PID logic controller for DC motor speed control systems. Software is developed in ‘C’ language using Si-Lab IDE C-cross compiler. The paper deals with the hardware and software details.

  17. Variable Rail Voltage Control of a Brushless DC (BLDC) Motor

    Science.gov (United States)

    2013-01-01

    Variable Rail Voltage Control of a Brushless DC (BLDC) Motor by Yuan Chen, Joseph Conroy, and William Nothwang ARL-TR-6308 January 2013...TR-6308 January 2013 Variable Rail Voltage Control of a Brushless DC (BLDC) Motor Yuan Chen, Joseph Conroy, and William Nothwang Sensors...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Variable Rail Voltage Control of a Brushless DC (BLDC) Motor 5a. CONTRACT NUMBER 5b. GRANT

  18. Pemodelan Dan Pembuatan Simulasi Kestabilan Respon Transien Motor Dc Menggunakan Graphical User Interface (Gui) Pada Matlab

    OpenAIRE

    Nurun Nayiroh, Mokhamad Tirono

    2008-01-01

    Motor DC (Direct Current) adalah motor yang digerakkan oleh energi listrik DC. Salah satu jenis motor DC tersebut ialah motor DC magnet permanen yang banyak ditemui penggunaannya baik di industri maupun di rumah tangga. Terapan motor DC kebanyakan merupakan sistem yang memerlukan pengatur kecepatan. Tujuan penelitian adalah untuk menghasilkan respon transien yang stabil dan performansi yang baik pada sistem motor DC.Sistem motor DC dimodelkan berdasarkan persamaan kesetimbangan torsi dan pers...

  19. Rotor position sensor switches currents in brushless dc motors

    Science.gov (United States)

    1965-01-01

    Reluctance switch incorporated in an induction motor is used for sensing rotor position and switching armature circuits in a brushless dc motor. This device drives the solar array system of an unmanned space satellite.

  20. Artificial Intelligent Controller for a DC Motor

    Science.gov (United States)

    Delavari, Hadi; Ranjbar Noiey, Abolzafl; Minagar, Sara

    The Speed and position control of DC motors is addressed in this paper. An optimal intelligent control scheme is proposed for the system. Preliminary a PID controller is designed using Genetic Algorithms (GA). The proposed controller is implemented by using optimal integral state feedback control with GA and Kalman filter. In the proposed scheme, performance depends on choosing weighting matrices Q and R in the cost function, and accordingly GA is used to find these proper weighting matrices. In order to reduce the control performance degradation due to system parameters variation, a Kalman filter is gained. The performance of the proposed technique (ISF) is compared with PID controller. Computer simulation validates the effectiveness of the proposed scheme even in presence of uncertainties.

  1. Integrated-Circuit Controller For Brushless dc Motor

    Science.gov (United States)

    Le, Dong Tuan

    1994-01-01

    Generic circuit performs commutation-logic and power-switching functions for control of brushless dc motor. Controller includes commutation-logic and associated control circuitry, power supply, and inverters containing power transistors. Major advantages of controller are size, weight, and power consumption can be made less than other brushless-dc-motor controllers.

  2. Controller for computer control of brushless dc motors. [automobile engines

    Science.gov (United States)

    Hieda, L. S. (Inventor)

    1981-01-01

    A motor speed and torque controller for brushless d.c. motors provides an unusually smooth torque control arrangement. The controller provides a means for controlling a current waveform in each winding of a brushless dc motor by synchronization of an excitation pulse train from a programmable oscillator. Sensing of torque for synchronization is provided by a light beam chopper mounted on the motor rotor shaft. Speed and duty cycle are independently controlled by controlling the frequency and pulse width output of the programmable oscillator. A means is also provided so that current transitions from one motor winding to another is effected without abrupt changes in output torque.

  3. Pulse-Width-Modulating Driver for Brushless dc Motor

    Science.gov (United States)

    Salomon, Phil M.

    1991-01-01

    High-current pulse-width-modulating driver for brushless dc motor features optical coupling of timing signals from low-current control circuitry to high-current motor-driving circuitry. Provides high electrical isolation of motor-power supply, helping to prevent fast, high-current motor-driving pulses from being coupled through power supplies into control circuitry, where they interfere with low-current control signals.

  4. Mathematical modeling of electromechanical processes in a brushless DC motor

    Directory of Open Access Journals (Sweden)

    V.I. Tkachuk

    2014-03-01

    Full Text Available On the basis of initial assumptions, a mathematical model that describes electromechanical processes in a brushless DC electric motor with a salient-pole stator and permanent-magnet excitation is created.

  5. Mathematical modeling of electromechanical processes in a brushless DC motor

    OpenAIRE

    V.I. Tkachuk; V.I. Zhuk

    2014-01-01

    On the basis of initial assumptions, a mathematical model that describes electromechanical processes in a brushless DC electric motor with a salient-pole stator and permanent-magnet excitation is created.

  6. Universal Brushless-DC Motor Controller for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this SBIR is to adapt an initial prototype ultra-miniature high-performance brushless-DC-motor controller, code named 'Puck', for use by NASA across a...

  7. Summary on Sensorless permanent magnet Brushless DC Motor Control Strategies

    Directory of Open Access Journals (Sweden)

    Li Hai Xia

    2016-01-01

    Full Text Available This paper aims at discussing the development process and application of permanent magnet brushless DC motor. By referring to the related literatures, this thesis gives an overview of several common non-position sensor detection technologies, analyzing their strengths and weaknesses as well as a number of new and improved methods in practical applications. Besides, The application situation of the electric door with sensorless permanent magnet brushless DC motor was illustrated.

  8. A Hybrid Model of a Brushless DC Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Hansen, Hans Brink; Kallesøe, Carsten Skovmose

    2007-01-01

    This paper presents a novel approach to modeling of a Brush-Less Direct Current Motor (BLDCM) driven by an inverter using hybrid systems theory. Hybrid systems combine continuous and discrete (event-based) dynamics, which is exactly the case in an inverter-driven BLDCM. The model presented...... in this work consists of a general automaton with discrete states, combined with a set of continuous dynamic equations describing the electro-mechanical behavior of the motor. One of the significant benefits of this strategy is that the model describes the motor under all possible operating conditions...

  9. Brushless dc motors. [applications in non-space technology

    Science.gov (United States)

    1975-01-01

    Brushless dc motors were intensively developed and tested over several years before qualification as the prime movers for Apollo Spacecraft life support blowers, and for circulating oxygen in the lunar portable life support system. Knowledge gained through prototype development and critical testing has significantly influenced the technology employed, broadened markets and applications, and reduced the cost of present day motors.

  10. A brushless dc spin motor for momentum exchange altitude control

    Science.gov (United States)

    Stern, D.; Rosenlieb, J. W.

    1972-01-01

    Brushless dc spin motor is designed to use Hall effect probes as means of revolving rotor position and controlling motor winding currents. This results in 3 to 1 reduction in watt-hours required for wheel acceleration, a 2 to 1 reduction in power to run wheel, and a 10 to 1 reduction in the electronics size and weight.

  11. Design optimization of brushed permanent magnet D C motor by genetic algorithm

    CERN Document Server

    Amini, S

    2002-01-01

    Because of field winding replacement with permanent magnet in brushed permanent magnet D C (PMDC) motors, field losses are eliminated and the structure of the motor is more simple. Efficiency of these motors is therefore increased and the manufacturing process is simplified. Hence, these motors are commonly used in low power applications and their design and optimization is an important consideration. Genetic algorithms are proposed for design optimization of PMD motors because of their independence to objective function structure and its derivative. In this paper genetic algorithms are evaluated for PMDC motor design optimization. an introduction is first presented about PMDC motors, general design procedure and elements of their optimization. Genetic algorithms are then briefly described. Finally results of optimization by genetic algorithms are compared with the one obtained using a conventional method.

  12. Photovoltaic-wind hybrid system for permanent magnet DC motor

    Science.gov (United States)

    Nasir, M. N. M.; Lada, M. Y.; Baharom, M. F.; Jaafar, H. I.; Ramani, A. N.; Sulaima, M. F.

    2015-05-01

    Hybrid system of Photovoltaic (PV) - Wind turbine (WT) generation has more advantages and reliable compared to PV or wind turbine system alone. The aim of this paper is to model and design hybrid system of PV-WT supplying 100W permanent-magnet dc motor. To achieve the objective, both of PV and WT are connected to converter in order to get the same source of DC supply. Then both sources were combined and straightly connected to 100W permanent magnet dc motor. All the works in this paper is only applied in circuit simulator by using Matlab Simulink. The output produced from each converter is expected to be suit to the motor specification. The output produced from each renewable energy system is as expected to be high as it can support the motor if one of them is breakdown

  13. System For Characterizing Three-Phase Brushless dc Motors

    Science.gov (United States)

    Howard, David E.; Smith, Dennis A.

    1996-01-01

    System of electronic hardware and software developed to automate measurements and calculations needed to characterize electromechanical performances of three-phase brushless dc motors, associated shaft-angle sensors needed for commutation, and associated brushless tachometers. System quickly takes measurements on all three phases of motor, tachometer, and shaft-angle sensor simultaneously and processes measurements into performance data. Also useful in development and testing of motors with not only three phases but also two, four, or more phases.

  14. Controller for a High-Power, Brushless dc Motor

    Science.gov (United States)

    Fleming, David J.; Makdad, Terence A.

    1987-01-01

    Driving and braking torques controllable. Control circuit operates 7-kW, 45-lb-ft (61-N-m), three-phase, brushless dc motor in both motor and generator modes. In motor modes, energy from power source is pulse-width modulated to motor through modified "H-bridge" circuit, in generator mode, energy from motor is pulse-width modulated into bank of load resistors to provide variable braking torques. Circuit provides high-resolution torque control in both directions over wide range of speeds and torques. Tested successfully at bus voltages up to 200 Vdc and currents up to 45 A.

  15. 18-12 Salient-Pole structure Brushless dc Motor with an assisted dc Field coil: Design Optimization and Numerical Analysis on the Magnetic Field

    Directory of Open Access Journals (Sweden)

    Hassan Moradi CheshmehBeigi

    2015-12-01

    Full Text Available Abstract. This paper presents the design optimization and accurate electromagnetic field analysis of an 18-12 there phase Brushless dc motor (BLDCM by using a three-dimensional Finite-Element analysis. Proposed motor will provide a wide range of air-gap flux control by a dc assisted field winding which is replaced with the permanent magnet in the rotor structure. In proposed BLDCM a simple dc current control is used and no brushes or slip rings are required to perform this control. To achieve the required performance within a specified space envelope, the physical dimensions of the proposed configuration were optimized; subject to maximize the average output power. Proposed 18-12 BLDCM configuration has been compared with a 9-6 BLDCM configuration. To evaluate the motor performance, the numerical techniques have been utilized. In the numerical part, 3-D Finite Element (FE analysis has been carried out using a MagNet CAD package (Infolytica Corporation Ltd. for two type of BLDCM to confirm the accuracy and the efficacy of the proposed design procedure. The analysis results demonstrate the effectiveness of the proposed machine design methodology. Keywords: FE Analysis; Field analysis; Brushless Dc Motor ­­­

  16. Parameters identification of a permanent magnet DC motor

    Energy Technology Data Exchange (ETDEWEB)

    Salah, M. [Univ. College of Applied Science, Gaza, Palestine (Israel); Abdelati, M. [Islamic Univ. of Gaza, Gaza, Palestine (Israel)

    2010-03-09

    Due to precise, wide, simple, and continuous control characteristics, direct current (DC) motors have been commonly employed in many industrial applications such as electric vehicles, steel rolling mills, electric cranes, and robotic manipulators. Because of their lower cost and ease of controller implementation, DC motors are preferred over alternating current (AC) motors. System identification of DC motors is of great importance in control problems. Accurate mathematical models and their parameters are necessary when designing controllers. This paper addressed driver circuits and parameters identification of a permanent magnet DC motor. An experimental measurement of armature voltage, armature current and rotor speed were performed using a data acquisition module in order to identify the parameters of the motor. DAQ toolbox and Simulink in MATLAB were used to obtain test signals and perform analysis based on the nonlinear least square method. The extracted motor parameters produced consistent simulation results with experimental data. It was concluded that the proposed approach is simple, fast and accurate. 16 refs., 4 tabs., 9 figs.

  17. The Model of Brushless Dc Motor Drive

    Directory of Open Access Journals (Sweden)

    Aurelijus Pitrėnas

    2013-05-01

    Full Text Available The research considered the operation, control, mathematical and simulation models of BLDC motor. A simplified idealized simulation model was designed and tested using Matlab Simulink software package. The simulation model uses Hall effect sensor signals for determining the rotor position. Simulation was done for Maxon, EC-4 pole 22 BL A series motor. The obtained model testing results deviate from the data supplied by the motor manufacturer by as little as 0.2–10.6%; consequently, the implemented model is suitable for BLDC motor control study and research.Article in Lithuanian

  18. Forward and Reverse Motoring of DC Hoist Motor on Container Crane (CC) Operation

    OpenAIRE

    Rukmini; Nadjamuddin Harun

    2015-01-01

    Container cranes (CC) become the highest electric energy consumption equipment in container terminal. Therefore it is important to study and analyze the hoist motor as the largest motor on container crane operation to look for opportunities in use energy efficiently. Lifting and lowering the container as the fixed operation of CC. Lifting the container as forward operating of hoist motor and lowering the container as reverse operating of hoist motor. The type of DC motor have used...

  19. Hall effect encoding of brushless dc motors

    Science.gov (United States)

    Berard, C. A.; Furia, T. J.; Goldberg, E. A.; Greene, R. C.

    1970-01-01

    Encoding mechanism integral to the motor and using the permanent magnets embedded in the rotor eliminates the need for external devices to encode information relating the position and velocity of the rotating member.

  20. (PFC) converters feeding brushless DC motor drive

    African Journals Online (AJOL)

    DR OKE

    1Department of Electrical Engineering, Indian Institute of Technology Delhi, INDIA ... configurations of PFC converters feeding BLDC motor drive are presented as low ..... In future, it is expected for a continuing research in the quest of energy ...

  1. DC motors and servo-motors controlled by Raspberry Pi 2B

    Directory of Open Access Journals (Sweden)

    Šustek Michal

    2017-01-01

    Full Text Available The expanding capabilities of today’s microcontrollers and other devices lead to an increased utilization of these technologies in diverse fields. The automation and issue of remote control of moving objects belong to these fields. In this project, a microcontroller Raspberry Pi 2B was chosen for controlling DC motors and servo-motors. This paper provides basic insight into issue of controlling DC motors and servo-motors, connection between Raspberry and other components on breadboard and programming syntaxes for controlling motors in Python programming language.

  2. James Webb Space Telescope Deployment Brushless DC Motor Characteristics Analysis

    Science.gov (United States)

    Tran, Ahn N.

    2016-01-01

    A DC motor's performance is usually characterized by a series of tests, which are conducted by pass/fail criteria. In most cases, these tests are adequate to address the performance characteristics under environmental and loading effects with some uncertainties and decent power/torque margins. However, if the motor performance requirement is very stringent, a better understanding of the motor characteristics is required. The purpose of this paper is to establish a standard way to extract the torque components of the brushless motor and gear box characteristics of a high gear ratio geared motor from the composite geared motor testing and motor parameter measurement. These torque components include motor magnetic detent torque, Coulomb torque, viscous torque, windage torque, and gear tooth sliding torque. The Aerospace Corp bearing torque model and MPB torque models are used to predict the Coulomb torque of the motor rotor bearings and to model the viscous components. Gear tooth sliding friction torque is derived from the dynamo geared motor test data. With these torque data, the geared motor mechanical efficiency can be estimated and provide the overall performance of the geared motor versus several motor operating parameters such as speed, temperature, applied current, and transmitted power.

  3. High-temperature brushless DC motor controller

    Energy Technology Data Exchange (ETDEWEB)

    Cieslewski, Crzegorz; Lindblom, Scott C.; Maldonado, Frank J.; Eckert, Michael Nathan

    2017-05-16

    A motor control system for deployment in high temperature environments includes a controller; a first half-bridge circuit that includes a first high-side switching element and a first low-side switching element; a second half-bridge circuit that includes a second high-side switching element and a second low-side switching element; and a third half-bridge circuit that includes a third high-side switching element and a third; low-side switching element. The motor controller is arranged to apply a pulse width modulation (PWM) scheme to switch the first half-bridge circuit, second half-bridge circuit, and third half-bridge circuit to power a motor.

  4. (PFC) converters feeding brushless DC motor drive

    African Journals Online (AJOL)

    DR OKE

    BLDC motor finds applications in variety of appliances used in domestic and household purposes, electrical vehicles and transportation, aerospace applications, medical equipments, medium power industrial tools, heating ventilation and air- conditioning (HVAC), precise motion control and industrial automation [1-4].

  5. Hybrid Adaptive Observer for a Brushless DC Motor

    DEFF Research Database (Denmark)

    Niemczyk, Piotr; Porchez, Thomas; Bendtsen, Jan Dimon

    2008-01-01

    A novel hybrid adaptive observer for Brushless DC Motors (BLDCM) is presented. It uses two current measurements of BLDCM phases to estimate the angle and the speed of the rotor. The observer is designed on the basis of a hybrid model, which is also presented in this paper. The parameters of the o...

  6. control of a dc motor using fuzzy logic control algorithm

    African Journals Online (AJOL)

    user

    This study sought to establish the impact of a fuzzy logic controller (FLC) and a Proportional-Integral-Derivative (PID) controller in the control performance of an industrial type DC motor using MATLAB. The fuzzy logic controller was developed on the basis of Mamdani type fuzzy inference system (FIS). The centroid method ...

  7. Design of dual DC motor control system based on DSP

    Science.gov (United States)

    Shi, Peicheng; Wang, Suo; Xu, Zengwei; Xiao, Ping

    2017-08-01

    Multi-motor control systems are widely used in actual production and life, such as lifting stages, robots, printing systems. This paper through serial communication between PC and DSP, dual DC motor control system consisting of PC as the host computer, DSP as the lower computer with synchronous PWM speed regulation, commutation and selection functions is designed. It sends digital control instructions with host computer serial debugger to lower computer, to instruct the motor to complete corresponding actions. The hardware and software design of the control system are given, and feasibility and validity of the control system are verified by experiments. The expected design goal is achieved.

  8. Increasing Mud Pump Motor Reliability against Malfunctions of DC Motor Excitation System

    Science.gov (United States)

    Nikulin, O. V.; Shabanov, V. A.

    2017-10-01

    The most widely used drilling machinery, such as mud pumps, draw-works, and rotors, use direct-current (DC) motors with independent excitation as the electric drive. Drilling machinery drives operate in harsh ambient conditions, including those with the presence of moisture, dust and vibration, which increases the malfunction rate of both drilling equipment and their electric drives. One of the frequently encountered malfunctions are DC motor excitation coil faults, which disrupt the normal functioning of electric drives, often leading to shutdown of the drilling process. In a four-pole DC motor, the malfunction of one coil leads to lack of excitation current in just one coil pair, while the other pair remains functional. In this case, DC motors and drilling equipment can remain operational, which would allow for continuing the drilling process. This paper considers the possibility of operation of a DC motor on a drilling rig in those cases when one pair of excitation coils is non-functional, and describes the device for switching between the excitation coils and the auxiliary winding in a DC motor with independent excitation.

  9. Estimation of Nonlinear DC-Motor Models Using a Sensitivity Approach

    DEFF Research Database (Denmark)

    Knudsen, Morten; Jensen, J.G.

    1995-01-01

    A nonlinear model structure for a permanent magnet DC-motor, appropriate for simulation and controller design, is developed.......A nonlinear model structure for a permanent magnet DC-motor, appropriate for simulation and controller design, is developed....

  10. Rapid Control Prototyping Plataform for Didactic Plant Motor DC

    Directory of Open Access Journals (Sweden)

    Cristian Bazán-Orobio

    2013-06-01

    Full Text Available In this paper a design, implementation and validation of a Rapid Control Prototype platform for a plant based on a DC motor is proposed. This low-cost prototype provides of an electronic card (with a motor DC and sensors manipulated by PC with free software tools using Linux, Scilab / Scicos and RTAI-Lab. This RCP System allows developing speed -position control trainings by using different types of PID industrial controllers with anti – wind up and bump less transfer schemes. We develop a speed control application structured in four steps: identification, controller design, simulation and real time control, where there are pedagogical advantages of a platform that not only allows simulation but also real-time control of a plant.

  11. Perancangan HMI (Human Machine Interface Untuk Pengendalian Kecepatan Motor DC

    Directory of Open Access Journals (Sweden)

    Heri Haryanto

    2016-03-01

    Full Text Available HMI (Human Machine Interface adalah sistem yang menghubungkan antara manusia dan mesin. Sistem HMI berupa Graphic user interface (GUI pada suatu tampilan layar komputer yang akan dihadapi oleh operator mesin atau pengguna yang akan memonitoring dan mengendalikan kecepatan motor DC dengan metode PID secara real time. Penelitian dilakukan dengan merancang sebuah sistem HMI menggunakan software Labview 2009. Hasil pengujian sistem monitoring pengendalian motor DC pada fungsi tombol knop dan tombol on/off yang divisualisasikan sudah berperan sesuai dengan fungsinya dengan waktu sampling 70 ms. Kendali PID yang sesuai dengan karakteristik sistem yang telah dibuat adalah Kp =1 Ki =4 Kd =0.3 dengan time delay 0,49 detik, rise time sebesar 1,99 detik, settling time sebesar 2,24 detik, dan steady state error sebesar 1,76%

  12. Disc rotors with permanent magnets for brushless DC motor

    Science.gov (United States)

    Hawsey, Robert A.; Bailey, J. Milton

    1992-01-01

    A brushless dc permanent magnet motor drives an autonomous underwater vehe. In one embodiment, the motor comprises four substantially flat stators in stacked relationship, with pairs of the stators axially spaced, each of the stators comprising a tape-wound stator coil, and first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of permanent magnets embedded therein. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and a drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore in which the first shaft is disposed. Two different sets of bearings support the first and second shafts. In another embodiment, the motor comprises two ironless stators and pairs of rotors mounted on opposite sides of the stators and driven by counterrotating shafts.

  13. Active Wheatstone Bridge — A solution of tight speed dc motor control

    African Journals Online (AJOL)

    Very tight control of the speed of a d.c. motor drive may be achieved by incorporating the machine within a closed loop system. The employed feedback signal is proportional to the motor speed for comparison against a reference quantity. For armature-controlled d.c. motors the difference or error signal provides appropriate ...

  14. Low speed phaselock speed control system. [for brushless dc motor

    Science.gov (United States)

    Fulcher, R. W.; Sudey, J. (Inventor)

    1975-01-01

    A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry.

  15. Development of Electronic Circulating Pump by Axial Air-gap Type Brush less Motor for Boiler

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Uk; Lee, Chang Eon; Kim, Young Seok; Yim, Chang Soon [Inha University (Korea, Republic of); Kim, Dong Chun [Pyung Taek Technical Junior College (Korea, Republic of); Suh, Sung Won [Bupyung Technical High School (Korea, Republic of)

    1997-04-30

    Canned type household circulating pump in the country almost depends on the act of imports, however it has disadvantage of low efficiency because an air gap of between rotor and stator is large and when the boiler is not used in a period of summer, a can and a rotor become adhered each other. Accordingly the pump is impossible to drive the initial state, and a lifetime of the pump gets shortening. To overcome these defects a electronic circulating pump by axial air-gap type brush less motor which is completely depart from the general idea for the conventional pump is developed. This paper is verified through experiments that the developed pump has good performance for reduction of size and noise, retrenchment of cost, and improvement of efficiency in comparison with the conventional pump. (author). refs., figs., tabs.

  16. Speed Control Analysis of Brushless DC Motor Based on Maximum Amplitude DC Current Feedback

    Directory of Open Access Journals (Sweden)

    Hassan M.A.A.

    2014-07-01

    Full Text Available This paper describes an approach to develop accurate and simple current controlled modulation technique for brushless DC (BLDC motor drive. The approach is applied to control phase current based on generation of quasi-square wave current by using only one current controller for the three phases. Unlike the vector control method which is complicated to be implemented, this simple current modulation technique presents advantages such as phase currents are kept in balance and the current is controlled through only one dc signal which represent maximum amplitude value of trapezoidal current (Imax. This technique is performed with Proportional Integral (PI control algorithm and triangular carrier comparison method to generate Pulse Width Modulation (PWM signal. In addition, the PI speed controller is incorporated with the current controller to perform desirable speed operation of non-overshoot response. The performance and functionality of the BLDC motor driver are verified via simulation by using MATLAB/SIMULINK. The simulation results show the developed control system performs desirable speed operation of non-overshoot and good current waveforms.

  17. Graphical User Interface Aided Online Fault Diagnosis of Electric Motor - DC motor case study

    OpenAIRE

    POSTALCIOGLU OZGEN, S.

    2009-01-01

    This paper contains graphical user interface (GUI) aided online fault diagnosis for DC motor. The aim of the research is to prevent system faults. Online fault diagnosis has been studied. Design of fault diagnosis has two main levels: Level 1 comprises a traditional control loop; Level 2 contains knowledge based fault diagnosis. Fault diagnosis technique contains feature extraction module, feature cluster module and fault decision module. Wavelet analysis has been used for the feature extract...

  18. Torque control of a separate excitation DC motor for a dynamometer

    OpenAIRE

    Derges, Jonathan R.

    2010-01-01

    Approved for public release; distribution is unlimited In this thesis, the theory behind a separate-winding excitation direct current (DC) motor and profile of the motor's torque versus rotor speed is studied. The torque versus rotor speed profile results are predictably linear at a given armature voltage. Output torque of a separate-winding excitation DC motor is proportional to the armature current. From this theory, a program was written in Simulink with Xilinx embedded software to enab...

  19. Soft commutated direct current motor [summary of proposed paper

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, John S.

    1998-10-22

    A novel soft commutated direct current (DC) motor is introduced. The current of the commutated coil is intentionally drained before the brush disconnects the coil. This prevents the spark generation that normally occurs in conventional DC motors. A similar principle can be applied for DC generators.

  20. Three-Wheel Brush-Wheel Sampler

    Science.gov (United States)

    Duckworth, Geoffrey A.; Liu, Jun; Brown, Mark G.

    2010-01-01

    A new sampler is similar to a common snow blower, but is robust and effective in sample collection. The brush wheels are arranged in a triangle shape, each driven by a brushless DC motor and planetary gearhead embedded in the wheel shaft. Its speed can be varied from 800 - 2,000 rpm, depending on the surface regolith resistance. The sample-collecting flow path, and internal features, are designed based on flow dynamics, and the sample-collecting rates have consistently exceeded the requirement under various conditions that span the range of expected surface properties. The brush-wheel sampler (BWS) is designed so that the flow channel is the main body of the apparatus, and links the brush-wheel assembly to the sample canister. The combination of the three brush wheels, the sample flow path, and the canister location make sample collection, storage, and transfer an easier task.

  1. Dynamic modeling of brushless dc motors for aerospace actuation

    Science.gov (United States)

    Demerdash, N. A.; Nehl, T. W.

    1980-01-01

    A discrete time model for simulation of the dynamics of samarium cobalt-type permanent magnet brushless dc machines is presented. The simulation model includes modeling of the interaction between these machines and their attached power conditioners. These are transistorized conditioner units. This model is part of an overall discrete-time analysis of the dynamic performance of electromechanical actuators, which was conducted as part of prototype development of such actuators studied and built for NASA-Johnson Space Center as a prospective alternative to hydraulic actuators presently used in shuttle orbiter applications. The resulting numerical simulations of the various machine and power conditioner current and voltage waveforms gave excellent correlation to the actual waveforms collected from actual hardware experimental testing. These results, numerical and experimental, are presented here for machine motoring, regeneration and dynamic braking modes. Application of the resulting model to the determination of machine current and torque profiles during closed-loop actuator operation were also analyzed and the results are given here. These results are given in light of an overall view of the actuator system components. The applicability of this method of analysis to design optimization and trouble-shooting in such prototype development is also discussed in light of the results at hand.

  2. Electric vehicle motors and controllers

    Science.gov (United States)

    Secunde, R. R.

    1981-01-01

    Improved and advanced components being developed include electronically commutated permanent magnet motors of both drum and disk configuration, an unconventional brush commutated motor, and ac induction motors and various controllers. Test results on developmental motors, controllers, and combinations thereof indicate that efficiencies of 90% and higher for individual components, and 80% to 90% for motor/controller combinations can be obtained at rated power. The simplicity of the developmental motors and the potential for ultimately low cost electronics indicate that one or more of these approaches to electric vehicle propulsion may eventually displace presently used controllers and brush commutated dc motors.

  3. Research of subdivision driving technology for brushless DC motors in optical fiber positioning

    Science.gov (United States)

    Kan, Yi; Gu, Yonggang; Zhu, Ye; Zhai, Chao

    2016-07-01

    In fiber spectroscopic telescopes, optical fiber positioning units are used to position thousands of fibers on the focal plane quickly and precisely. Stepper motors are used in existing units, however, it has some inherent deficiencies, such as serious heating and low efficiency. In this work, the universally adopted subdivision driving technology for stepper motors is transplanted to brushless DC motors. It keeps the advantages of stepper motors such as high positioning accuracy and resolution, while overcomes the disadvantages mentioned above. Thus, this research mainly focuses on develop a novel subdivision driving technology for brushless DC motor. By the proving of experiments of online debug and subdivision speed and position, the proposed brushless DC motor subdivision technology can achieve the expected functions.

  4. Perancangan Zeta Converter yang dilengkapi Power Factor Correction pada Aplikasi Pengaturan Kecepatan Motor Brushless DC

    Directory of Open Access Journals (Sweden)

    Adhika Prajna Nandiwardhana

    2017-01-01

    Full Text Available Penggunaan motor brushless DC telah banyak digunakan dalam berbagai bidang seperti peralatan rumah tangga maupun industri dikarenakan motor ini memiliki struktur yang sederhana, efisiensi dan torsi yang tinggi, serta menggunakan konsep komutasi elektris yang berbeda dari motor DC lainnya. Namun pengoperasian pada umumnya yang menggunakan sumber AC, penyearah serta inverter membuat tingginya nilai harmonisa arus (THD sebesar 73,33% dan power factor sebesar 0,803 dimana nilai ini kurang baik dalam pengaplikasiannya. Pada penelitian ini akan dikaji mengenai proses power factor correction yang mereduksi harmonisa arus (THD sumber AC dengan menggunakan zeta converter dalam pengaplikasian motor brushless DC, serta pengoperasian motor dengan mengamati respon motor terhadap kecepatan referensi yang berubah-ubah dan mengamati kestabilan motor terhadap pembebanan yang bervariasi. Dalam menerapkan metode yang dilakukan pada penelitian ini, pengoperasian motor brushless DC yang telah dirancang dapat bekerja dengan baik meliputi respon motor yang dapat mengikuti kecepatan referensi yang berubah-ubah, serta kestabilan motor dalam mempertahankan kecepatannya pada pembebanan yang bervariasi. Proses power factor correction dapat meningkatkan kualitas daya pada berbagai kecepatan dan mode penerapan yang berbeda-beda, dimana peningkatan tersebut membuktikan kinerja yang baik dalam sistem ini dan memiliki nilai kualitas daya yang baik.

  5. Straight and chopped dc performance data for a General Electric 5BY436A1 dc shunt motor with a General Electric EV-1 controller

    Energy Technology Data Exchange (ETDEWEB)

    Edie, P C

    1981-10-01

    Both straight and chopped dc motor performance data for a General Electric 5BY436A1 motor with a General Electric EV-1 controller are presented in tabular and graphical formats. Effects of motor temperature and operating voltage are also shown. The maximum motor efficiency is approximately 85% at low operating temperatures in the straight dc mode. Chopper efficiency can be assumed to be 95% under all operating conditions. For equal speeds, the motor operated in the chopped mode develops slightly more torque and draws more current than it does in the straight dc mode.

  6. System and Method for Determining Rate of Rotation Using Brushless DC Motor

    Science.gov (United States)

    Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2000-01-01

    A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is squared. The squared outputs associated with each winding are combined, with the square root being taken of such combination, to produce a DC output proportional only to the rate of rotation of the motor's shaft.

  7. Rate of rotation measurement using back-EMFS associated with windings of a brushless DC motor

    Science.gov (United States)

    Howard, David E. (Inventor)

    2000-01-01

    A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is integrated and multiplied by the back-emf associated with an adjacent winding. The multiplied outputs associated with each winding are combined to produce a directionally sensitive DC output proportional only to the rate of rotation of the motor's shaft.

  8. AVR Microcontroller-based automated technique for analysis of DC motors

    Science.gov (United States)

    Kaur, P.; Chatterji, S.

    2014-01-01

    This paper provides essential information on the development of a 'dc motor test and analysis control card' using AVR series ATMega32 microcontroller. This card can be interfaced to PC and calculates parameters like motor losses, efficiency and plot characteristics for dc motors. Presently, there are different tests and methods available to evaluate motor parameters, but a single and universal user-friendly automated set-up has been discussed in this paper. It has been accomplished by designing a data acquisition and SCR bridge firing hardware based on AVR ATMega32 microcontroller. This hardware has the capability to drive the phase-controlled rectifiers and acquire real-time values of current, voltage, temperature and speed of motor. Various analyses feasible with the designed hardware are of immense importance for dc motor manufacturers and quality-sensitive users. Authors, through this paper aim to provide details of this AVR-based hardware which can be used for dc motor parameter analysis and also for motor control applications.

  9. Finite Control Set Model Predictive Speed Control of a DC Motor

    Directory of Open Access Journals (Sweden)

    Viktor Šlapák

    2016-01-01

    Full Text Available The paper describes the design procedure for a finite control set model predictive control (FCS-MPC of brushed permanent magnet DC (PMDC machine supplied from DC-DC converter. Full order linear Kalman filter is used for estimation of an unmeasured load torque and reduction of speed measurement noise. A new cost function has been introduced with a feedforward dynamic current component and a feedforward static load current component. The performance of the proposed control strategy is compared to the conventional PI-PWM cascade speed control through the experimental verification on the 250 W laboratory prototype. Obtained results show excellent dynamic behaviour and indicate possible energy savings of the proposed speed control.

  10. Permanent magnet brushless DC motor drives and controls

    CERN Document Server

    Xia, Chang-liang

    2012-01-01

    An advanced introduction to the simulation and hardware implementation of BLDC motor drives A thorough reference on the simulation and hardware implementation of BLDC motor drives, this book covers recent advances in the control of BLDC motor drives, including intelligent control, sensorless control, torque ripple reduction and hardware implementation. With the guidance of the expert author team, readers will understand the principle, modelling, design and control of BLDC motor drives. The advanced control methods and new achievements of BLDC motor drives, of interest to more a

  11. Research on Control System of Three - phase Brushless DC Motor for Electric Vehicle

    Science.gov (United States)

    Wang, Zhiwei; Jin, Hai; Guo, Jie; Su, Jie; Wang, Miao

    2017-12-01

    In order to study the three-phase brushless motor control system of electric vehicle, Freescale9S12XS128 chip is used as the control core, and the power MOSFET is used as the inverter device. The software is compiled by Codewarrior software. The speed control link adopts open-loop control, and the control chip collects the external sensor signal voltage Change control PWM signal output control three-phase brushless DC motor speed. The whole system consists of Hall position detection module, current detection module, power drive module and voltage detection module. The basic functions of three-phase brushless DC motor drive control are realized.

  12. The electric motor handbook

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, R.W.; Feltham, P. (eds.)

    2004-05-01

    This handbook outlines the important role that electric motors play in modern society. It covers the field of motor applications from various motor types to their use and repair. It also presents practical applications of electric motors and methods on motor efficiency. More than half of all electricity generated, and 75 per cent of all industrial electricity consumption is consumed by electric motors. Electrical personnel must be aware of all factors involved in electric motors in order to choose and apply the appropriate size of electric motor. These factors include efficiency, sizing and proper application. The efficient use and maximum life expectancy of electric motors depends on proper motor protection, control and maintenance. This handbook includes articles from leading experts on electric motors in modern electrical systems. The content includes: design considerations; proper electric motor sizing techniques; optimal electric motor application; electric motor protection technology; electric motor control principles; electric motor maintenance and troubleshooting; induction electric motors; electric motor bearing currents; electric motor bearing lubrication; electromagnetism; electric motor enclosures; electric motor testing; electric motor repair; DC electric motor; electric motor starters; electric motor brushes; industrial electric motors; electric motor diagrams; AC electric motors; electric motor wiring; electric motor service; electric motor rewinding; electric motor winding; diagram of electric motor wiring; electric motor kit; and, troubleshooting electric motors. A directory of motor manufacturers and suppliers was also included. refs., tabs., figs.

  13. Development of a New Method for Assembling a Bipolar DC Motor as a Teaching Material

    Science.gov (United States)

    Matsumoto, Yuki; Sakaki, Kei; Sakaki, Mamoru

    2017-05-01

    A simple handmade motor is a commonly used teaching aid for explaining the theory of the DC motor in science classes around the world. Kits that can be used by children to craft a simple motor are commercially available, and videos of assembling these motors are easily found on the internet. Although the design of this motor is simple, it is unipolar, meaning that the rotor consists of a single dipole. Thus, the Lorentz force acts only on one side of the coil per revolution. This decreases the energy conversion efficiency and requires the learners to turn the rotor using their hands in order to initiate rotation.

  14. Analysis of Engine Propeller Matching of DC Motor as a Main Propulsion

    Directory of Open Access Journals (Sweden)

    Eddy Setyo Koenhardono

    2017-12-01

    Full Text Available The development of ship always searches through the most benefits system for reducing costs of propulsion system without increase pollution. Diesel propulsion system or also known as conventional propulsion system is efficient but requires high operating costs and increase high level of marine pollution. Electrical propulsion system is using electric motors as the prime mover of the propeller. There are 2 types of electric motors that will be used for research of electric propulsion system, there are; DC motors and three-phases induction motor. As the use of DC motor as a prime mover for this electrical propulsion system, this study determines the characteristic between voltage terminal with torque and also field current with torque. It results that torque produced by the DC motor is in the same magnitude with the speed (RPM. The higher the speed have shaped the value of the torque. The input and terminal voltages adjusts all variables and results. In this study, different field voltage creates different pattern of motor envelope. Its manner to propeller curve occurs total different results. With field voltage of 50 V, the ranges of motor envelope immoveable in the point of 150% of present speed and 160%. While field voltage of 60 V serves larger ranges of motor envelope which possible to reach further than 50 V curve.

  15. DC torque motor actuated anti-lock brake controller

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, P.D.; Kade, A.

    1989-02-21

    A wheel lock control system is described for limiting the brake pressure applied to the brake of a vehicle wheel traveling over a road surface, the system comprising: an actuator for controlling the brake pressure to the brake of the wheel, the actuator including a torque motor for generating a motor torque in response to motor current to control the applied brake pressure in accordance with the value of the motor torque, the motor torque having a value proportional to the value of the motor current; means for determining the tire torque tending to accelerate the wheel during the application of brake pressure; means for storing the value of motor current corresponding to the maximum determined value of tire torque; means for detecting an incipient wheel lockup condition; and means for establishing the motor current following a detected incipient wheel lockup condition at a value having a predetermined relationship to the stored value of motor current to control the brake pressure at a predetermined braking condition.

  16. performance characteristics of an armature voltage controlled dc motor

    African Journals Online (AJOL)

    Dr Obe

    types. To each of these two control arrangements is added an inner current controller loop. Using developed motor equations, the performance characteristics of a test motor are obtained by digital computer analysis. The results show that closed loop operation, with appropriate control gains, give improved speed regulation ...

  17. Neuro-Fuzzy DC Motor Speed Control Using Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Boumediene ALLAOUA

    2009-12-01

    Full Text Available This paper presents an application of Adaptive Neuro-Fuzzy Inference System (ANFIS control for DC motor speed optimized with swarm collective intelligence. First, the controller is designed according to Fuzzy rules such that the systems are fundamentally robust. Secondly, an adaptive Neuro-Fuzzy controller of the DC motor speed is then designed and simulated; the ANFIS has the advantage of expert knowledge of the Fuzzy inference system and the learning capability of neural networks. Finally, the ANFIS is optimized by Swarm Intelligence. Digital simulation results demonstrate that the deigned ANFIS-Swarm speed controller realize a good dynamic behavior of the DC motor, a perfect speed tracking with no overshoot, give better performance and high robustness than those obtained by the ANFIS alone.

  18. Research of Compound Control for DC Motor System Based on Global Sliding Mode Disturbance Observer

    Directory of Open Access Journals (Sweden)

    He Zhang

    2014-01-01

    Full Text Available Aiming at the problems of modeling errors, parameter variations, and load moment disturbances in DC motor control system, one global sliding mode disturbance observer (GSMDO is proposed based on the global sliding mode (GSM control theory. The output of GSMDO is used as the disturbance compensation in control system, which can improve the robust performance of DC motor control system. Based on the designed GSMDO in inner loop, one compound controller, composed of a feedback controller and a feedforward controller, is proposed in order to realize the position tracking of DC motor system. The gains of feedback controller are obtained by means of linear quadratic regulator (LQR optimal control theory. Simulation results present that the proposed control scheme possesses better tracking properties and stronger robustness against modeling errors, parameter variations, and friction moment disturbances. Moreover, its structure is simple; therefore it is easy to be implemented in engineering.

  19. Brushless DC Motor and Resolver for Venusian Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to the need for motors and actuators that can operate in the harsh venusian environment for extended periods of time, on the order of several hours to...

  20. Brushless DC Motor and Resolver for Venusian Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to the need for motors, actuators and sample acquisition system that can operate in the harsh Venusian environment for extended periods of time, on the...

  1. A Motor friendly Quasi-resonant DC-link Inverter

    OpenAIRE

    Kedarisetti, Jayalakshmi

    2012-01-01

    Feeding electrical motors by long cables using PWM inverters has become lately problematic due to developments in semiconductor technology. Most used in converters, insulated gate bipolar transistors IGBTs switch voltages with high gradients, about 10kV/μs. On one hand, faster switching transients lead to the reduction of switching losses and therefore, permissible higher switching frequencies, reduction of harmonics and audible noise at motors. On the other hand, bigger voltage gradients com...

  2. Static and dynamic wind turbine simulator using a converter controlled dc motor

    Energy Technology Data Exchange (ETDEWEB)

    Monfared, Mohammad; Rastegar, Hasan [Department of Electrical Engineering, Amirkabir University of Technology, Tehran (Iran); Madadi Kojabadi, Hossein [Department of Electrical Engineering, Sahand University of Technology, Tabriz 51335-1996 (Iran)

    2008-05-15

    This paper describes a new wind turbine simulator for dynamic conditions. The authors have developed an experimental platform to simulate the static and dynamic characteristics of real wind energy conversion system. This system consists of a 3 kW dc motor, which drives a synchronous generator. The converter is a 3 kW single-phase half-controlled converter. MATLAB/Simulink real time control software interfaced to I/O board and a converter controlled dc motor are used instead of a real wind turbine. A MATLAB/Simulink model is developed that obtains wind profiles and, by applying real wind turbine characteristics in dynamics and rotational speed of dc motor, calculates the command shaft torque of a real wind turbine. Based on the comparison between calculated torques with command one, the shaft torque of dc motor is regulated accordingly by controlling armature current demand of a single-phase half-controlled ac-dc converter. Simulation and experimental results confirm the effectiveness of proposed wind turbine simulator in emulating and therefore evaluating various turbines under a wide variety of wind conditions. (author)

  3. Incorporation of fractional-order dynamics into an existing PI/PID DC motor control loop.

    Science.gov (United States)

    Tepljakov, Aleksei; Gonzalez, Emmanuel A; Petlenkov, Eduard; Belikov, Juri; Monje, Concepción A; Petráš, Ivo

    2016-01-01

    The problem of changing the dynamics of an existing DC motor control system without the need of making internal changes is considered in the paper. In particular, this paper presents a method for incorporating fractional-order dynamics in an existing DC motor control system with internal PI or PID controller, through the addition of an external controller into the system and by tapping its original input and output signals. Experimental results based on the control of a real test plant from MATLAB/Simulink environment are presented, indicating the validity of the proposed approach. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Graphical User Interface Aided Online Fault Diagnosis of Electric Motor - DC motor case study

    Directory of Open Access Journals (Sweden)

    POSTALCIOGLU OZGEN, S.

    2009-10-01

    Full Text Available This paper contains graphical user interface (GUI aided online fault diagnosis for DC motor. The aim of the research is to prevent system faults. Online fault diagnosis has been studied. Design of fault diagnosis has two main levels: Level 1 comprises a traditional control loop; Level 2 contains knowledge based fault diagnosis. Fault diagnosis technique contains feature extraction module, feature cluster module and fault decision module. Wavelet analysis has been used for the feature extraction module. For the feature cluster module, fuzzy cluster has been applied. Faults effects are examined on the system using statistical analysis. In this study Fault Diagnosis technique obtains fault detection, identification and halting the system. In the meantime graphical user interface (GUI is opened when fault is detected. GUI shows the measurement value, fault time and fault type. This property gives some information about the system to the personnel. As seen from the simulation results, faults can be detected and identified as soon as fault appears. In summary, if the system has a fault diagnosis structure, system dangerous situations can be avoided.

  5. Brushless DC motor control system responsive to control signals generated by a computer or the like

    Science.gov (United States)

    Packard, D. T.

    1985-04-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The motor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor be regulated by applying a separate control signal and each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  6. Predictive diagnostic system for DC motor drives: Forest Products Project fact sheet

    Energy Technology Data Exchange (ETDEWEB)

    NREL

    2000-02-01

    This report is a fact sheet on new sensor and control technology written for the NICE3 Program. ENVATEC has addressed a major problem for paper producers with its ENVAIR 4000, a sensor and control technology that optimizes DC motor drive operations by simultaneously monitoring and analyzing eight inputs on DC motors. Attributes, such as motor air temperature, speed, vibration, relative humidity, presence of corrosive gases, airflow, and amperage, are measured for irregularities and then a signal is transmitted across the customer's facility on any network interface. This eliminates unscheduled motor shutdowns, thereby cutting energy costs tied to restarting. Based on successful prototype testing, the ENVAIR 4000 promises a 70% reduction in repair and replacement costs, an 80% reduction in unscheduled downtime and pulp waste, and a 43% drop in CO{sub 2} emissions.

  7. Adaptive fuzzy control of DC motors using state and output feedback

    Energy Technology Data Exchange (ETDEWEB)

    Rigatos, Gerasimos G. [Unit of Industrial Automation, Industrial Systems Institute, Stadiou str., 26504 Rion Patras (Greece)

    2009-11-15

    Conventional PID of state feedback controllers for DC motors have poor performance when changes of the motor or load dynamics take place. To handle this shortcoming adaptive fuzzy control of DC motors is proposed. Neuro-fuzzy networks are used to approximate the unknown motor dynamics. The information needed to generate the control signal comes from feedback of the full state vector or from feedback of only the system's output. In the latter case a state observer is used to estimate the parameters of the state vector. The stability of the closed-loop system is proved with the use of Lyapunov analysis. The performance of the proposed control approach is evaluated through simulation tests. (author)

  8. Optimal PID control of a brushless DC motor using PSO and BF techniques

    Directory of Open Access Journals (Sweden)

    H.E.A. Ibrahim

    2014-06-01

    Full Text Available This paper presents a Particle Swarm Optimization (PSO technique and bacterial foraging (BF technique for determining the optimal parameters of (PID controller for speed control of a brushless DC motor (BLDC where the (BLDC motor is modeled in simulink in Matlab. The proposed technique was more efficient in improving the step response characteristics as well as reducing the steady-state error, rise time, settling time and maximum overshoot.

  9. Simulation of Outer Rotor Permanent Magnet Brushless DC Motor Using Finite Element Method for Torque Improvement

    Directory of Open Access Journals (Sweden)

    Uma Devi Kumaravelu

    2012-01-01

    Full Text Available A method of simulation and modeling outer rotor permanent magnet brushless DC (ORPMBLDC motor under dynamic conditions using finite element method by FEMM 4.2 software package is presented. In the proposed simulation, the torque developed at various positions of the rotor, under a complete cycle of excitation of the stator, is analysed. A novel method of sinusoidal excitation is proposed to enhance the overall torque development of ORPMBLDC motor.

  10. Simulation of Outer Rotor Permanent Magnet Brushless DC Motor Using Finite Element Method for Torque Improvement

    OpenAIRE

    Uma Devi Kumaravelu; Sanavullah Mohamed Yakub

    2012-01-01

    A method of simulation and modeling outer rotor permanent magnet brushless DC (ORPMBLDC) motor under dynamic conditions using finite element method by FEMM 4.2 software package is presented. In the proposed simulation, the torque developed at various positions of the rotor, under a complete cycle of excitation of the stator, is analysed. A novel method of sinusoidal excitation is proposed to enhance the overall torque development of ORPMBLDC motor.

  11. Controlling the Dc-link Midpoint Potential in a Six-phase Motor-drive

    DEFF Research Database (Denmark)

    Bendixen, Flemming Buus; Blaabjerg, Frede; Rasmussen, Peter Omand

    2004-01-01

    Traditionally electrical motors have three phases, but multiphase motors have shown to improve motor performance and efficiency. This paper concentrates about the control algorithm for a six-phase induction motor with third harmonic current injection. The problem is that typically a seventh...... inverter branch and filter inductances is needed for stabilizing the midpoint potential of the series connected dc-capacitor link. A new control strategy that pre-calculates the allowed voltage ripple and controls the motor voltage accordingly (using two standard three phase inverter modules) is suggested....... With this new control strategy the seventh branch and an inductance can be saved. It also opens the possibility to use two standard three-phase inverters to supply the six-phase motor. An experimental setup is build and the theory is verified in the test case. The proposed control strategy works satisfactory...

  12. Control of a dc motor using fuzzy logic control algorithm | Usoro ...

    African Journals Online (AJOL)

    This study sought to establish the impact of a fuzzy logic controller (FLC) and a Proportional-Integral-Derivative (PID) controller in the control performance of an industrial type DC motor using MATLAB. The fuzzy logic controller was developed on the basis of Mamdani type fuzzy inference system (FIS). The centroid method ...

  13. Anti-control of chaos of single time-scale brushless DC motor.

    Science.gov (United States)

    Ge, Zheng-Ming; Chang, Ching-Ming; Chen, Yen-Sheng

    2006-09-15

    Anti-control of chaos of single time-scale brushless DC motors is studied in this paper. In order to analyse a variety of periodic and chaotic phenomena, we employ several numerical techniques such as phase portraits, bifurcation diagrams and Lyapunov exponents. Anti-control of chaos can be achieved by adding an external constant term or an external periodic term.

  14. Brushless DC motor control system responsive to control signals generated by a computer or the like

    Science.gov (United States)

    Packard, Douglas T. (Inventor); Schmitt, Donald E. (Inventor)

    1987-01-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The rotor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor may be regulated by applying a separate control signal to each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  15. Synchronization of the Fractional-Order Brushless DC Motors Chaotic System

    Directory of Open Access Journals (Sweden)

    Shiyun Shen

    2016-01-01

    Full Text Available Based on the extension of Lyapunov direct method for nonlinear fractional-order systems, chaos synchronization for the fractional-order Brushless DC motors (BLDCM is discussed. A chaos synchronization scheme is suggested. By means of Lyapunov candidate function, the theoretical proof of chaos synchronization is addressed. The numerical results show that the chaos synchronization scheme is valid.

  16. Synchronization of the Fractional-Order Brushless DC Motors Chaotic System

    OpenAIRE

    Shiyun Shen; Ping Zhou

    2016-01-01

    Based on the extension of Lyapunov direct method for nonlinear fractional-order systems, chaos synchronization for the fractional-order Brushless DC motors (BLDCM) is discussed. A chaos synchronization scheme is suggested. By means of Lyapunov candidate function, the theoretical proof of chaos synchronization is addressed. The numerical results show that the chaos synchronization scheme is valid.

  17. Low-Cost Undergraduate Control Systems Experiments Using Microcontroller-Based Control of a DC Motor

    Science.gov (United States)

    Gunasekaran, M.; Potluri, R.

    2012-01-01

    This paper presents low-cost experiments for a control systems laboratory module that is worth one and a third credits. The experiments are organized around the microcontroller-based control of a permanent magnet dc motor. The experimental setups were built in-house. Except for the operating system, the software used is primarily freeware or free…

  18. Novel Motion Sensorless Control of Single Phase Brushless D.C. PM Motor Drive, with experiments

    DEFF Research Database (Denmark)

    Lepure, Liviu Ioan; Boldea, Ion; Andreescu, Gheorghe Daniel

    2010-01-01

    A motion sensorless control for single phase permanent magnet brushless d.c. (PM-BLDC) motor drives, based on flux integration and prior knowledge of the PM flux/position characteristic is proposed here and an adequate correction algorithm is adopted, in order to increase the robustness to noise...

  19. Improved Analytical Model of a Permanent-Magnet Brushless DC Motor

    NARCIS (Netherlands)

    Kumar, P.; Bauer, P.

    2008-01-01

    In this paper, we develop a comprehensive model of a permanent-magnet brushless DC (BLDC) motor. An analytical model for determining instantaneous air-gap field density is developed. This instantaneous field distribution can be further used to determine the cogging torque, induced back electromotive

  20. Active Wheatstone Bridge — A solution of tight speed dc motor control

    African Journals Online (AJOL)

    This paper describes a technical application in which the armature of a d.c. motor is connected as one of the arms of a Wheatstone bridge, now becoming an active Wheatstone bridge. By analyzing the operation of the active Wheatstone bridge, its transfer function is derived. The active Wheatstone bridge is incorporated in ...

  1. Cheaper Synthesis Of Multipole-Brushless-dc-Motor Current

    Science.gov (United States)

    Alhorn, Dean C.; Howard, David E.

    1994-01-01

    Circuit converts output of single two-phase shaft-angle resolver to that of multi-speed three-phase shaft-angle resolver. Converter circuit applicable to generation of multispeed, multiphase shaft-angle-resolver signals from single two-phase shaft-angle resolver. Combination of converter circuit and single two-phase shaft-angle resolver offer advantages in cost, weight, size, and complexity. Design readily adaptable to two-phase motor.

  2. Implementation of FPGA based PID Controller for DC Motor Speed Control System

    Directory of Open Access Journals (Sweden)

    Savita SONOLI

    2010-03-01

    Full Text Available In this paper, the implementation of software module using ‘VHDL’ for Xilinx FPGA (XC3S400 based PID controller for DC motor speed control system is presented. The tools used for building and testing the software modules are Xilinx ISE 9.2i and ModelSim XE III 6.3c. Before verifying the design on FPGA the complete design is simulated using Modelsim Simulation tool. A test bench is written where the set speed can be changed for the motor. It is observed that the motor speed gradually changes to the set speed and locks to the set speed.

  3. Perancangan dan Pengujian Sistem Pengendali Sudut untuk Motor DC Brushless Menggunakan Kendali Algoritma P-D

    Directory of Open Access Journals (Sweden)

    Rizqi Andry Ardiansyah

    2017-08-01

    Full Text Available Many industrial applications use servo motor because of its accuracy and user-friendly, but by using it in an application, a higher cost is required.  To make an actuator with good precision and universal purpose but with lower cost, a position control system for brushless dc motor was built. To achieve a better precision in the position control for brushless DC motor, the system is utilized with a microcontroller ATmega 2560, an absolute encoder as a position sensor, and also Proportional-Derivative closed-loop control algorithm. In the final test, we obtained that the system worked well on average angular speed about 3.88º/ms and angle tolerance about 1º.

  4. Analysis and Stabilization of Chaos in Permanent Magnet DC Motor Driver

    Science.gov (United States)

    Tahir, Fadhil Rahma; Abdul-Hassan, Khalid M.; Abdullah, Mohammed Abbas; Pham, Viet-Thanh; Hoang, Thang Manh; Wang, Xiong

    In this paper, the nonlinear dynamics of permanent magnet (PM) DC motor drive with proportional (P) controller have been investigated. The drive system shows different dynamical behaviors; periodic, quasi-periodic, and chaotic behaviors, and those are characterized by using bifurcation diagram, phase portrait, and time series. The stability analysis of period-1 behavior is studied by using Filippov’s method, the analytic results show good agreement with simulation ones. Then, the stabilization of chaos to fixed point is carried out by using the sliding mode control (SMC). In addition, experimentally the nonlinear dynamics and the proposed stabilization method to PM DC motor drive system have been achieved by using a microcontroller. For the first time, it is noted that when the system is in chaotic dynamics, the vibration of the motor is increased approximately 400% compared with the system in periodic dynamical behavior.

  5. Characterization and enhancement of micro brushless DC motor response

    Science.gov (United States)

    Conroy, Joseph; Kehlenbeck, Andrew; Humbert, J. Sean; Nothwang, William

    2014-06-01

    Commercially available speed controllers, motors, and propellers typically comprise the powertrains of many micro aerial robotic systems, such as quadrotor vehicles. As on board state sensing and processing improves, actuation bandwidth is becoming a significant bottleneck that limits the performance of the entire closed loop system. The performance of the commercial products can be greatly enhanced through the implementation of classical control methods directly at the powertrain level. In this paper, reduced order open loop models for three representative commercially available powertrains were estimated and were compared with closed loop equivalents. Further performance improvement is realized by the addition of a static inverse to mitigate the steady state structured uncertainty of the system.

  6. Magnetic Circuit & Torque Analysis Of Brushless DC Motor

    Directory of Open Access Journals (Sweden)

    Arif J. Abbas

    2013-05-01

    Full Text Available       This work is concerned with magnetic and torque analysis of BLDCM and with development of a method of designing BLDCM that have symmetric winding on the rotor .make significant contribution to the rotor inductance position difficult. It is also show that the prediction detent torque can be extremely sensitive to the permanent magnet by altering magnet arc width. Finally, simple lumped models that allow one to predict motor performance and characteristics as a function of main dimension, magnet residual flux density and phase current are developed. These models are used as a basis for an approach to designing BLDCM

  7. Identification of the parameters of a DC motor state space model

    Directory of Open Access Journals (Sweden)

    Momir Ranislav Stanković

    2013-06-01

    Full Text Available A method for the identification of the DC state space model parameters based on the minimization of the error function using the least squares method is described in this paper. The algorithm is practically applied in the laboratory environment on an industrial DC motor. The verification of the results was performed by comparing the characteristic signals of real and modeled systems. The results show that the quality of the identification is satisfactory.   Introduction The identification of system parameters is the first step in the analysis and synthesis of control systems. Identification Quality strongly impacts on the results of all other computations. In the theory of automatic control, many methods of identification are developed. Which method will be applied depends on the characteristics of the system. In this paper, we described an identification algorithm based on the least squares method. A practical test of this algorithm of estimation is done on a DC motor.   parameter estimation with the least squares method   A DC motor is a second-order system described with two differential equations: one which describes electrical and one which describes mechanical parts of the motor. The idea is to analyse the motor as two first-order systems. The main signals are responses of two first order sub-systems on appropriate inputs. Using a discrete state-space model of the motor and applying the least square method on the recorded signals, we get straightforward equations for the computation of all the necessary parameters: Rr,  Lr ,  Je ,  Fe ,  Kme and Kem (Eykhoff, Wilsoons, 1974.   Experimental results   The practical application was realized in the laboratory where a DC middle-power motor was used as a control object. It is coupled with a DC generator which serves as a load. Generation of the input signals and measure of the responses were performed with the acquisition system based on the appropriate acquisition card and the MATLAB

  8. Speed response of brushless DC motor using fuzzy PID controller under varying load condition

    Directory of Open Access Journals (Sweden)

    Akash Varshney

    2017-09-01

    Full Text Available The increasing trend towards usage of precisely controlled, high torque, efficient and low noise motors for dedicated applications has attracted the attention of researcher in Brushless DC (BLDC motors. BLDC motors can act as an acceptable alternative to the conventional motors like Induction Motors, Switched Reluctance Motors etc. This paper presents a detailed study on the performance of a BLDC motor supplying different types of loads, and at the same time, deploying different control techniques. An advance Fuzzy PID controller is compared with the commonly used PID controller. The load variations considered are of the most common types, generally encountered in practice. A comparison has been carried out in this paper by observing the dynamic speed response of motor at the time of application as well as at the time of removal of the load. The BLDC motors suffer from a major drawback of having jerky behaviour at the time of load removal. The study reveals that irrespective of the type of controller used, the gradual load variation produces better results as against sudden load variations. It is further observed that in addition to other dynamic features, the jerks produced at the time of load removal also get improved to a large extent with Fuzzy PID controller.The speed torque characteristics unraveled the fact that the jerks are minimum at the time of gradual load removal with Fuzzy PID controller in place. An attempt has been made to define these jerks by ‘Perturbation Window’.

  9. Identification and adaptive neural network control of a DC motor system with dead-zone characteristics.

    Science.gov (United States)

    Peng, Jinzhu; Dubay, Rickey

    2011-10-01

    In this paper, an adaptive control approach based on the neural networks is presented to control a DC motor system with dead-zone characteristics (DZC), where two neural networks are proposed to formulate the traditional identification and control approaches. First, a Wiener-type neural network (WNN) is proposed to identify the motor DZC, which formulates the Wiener model with a linear dynamic block in cascade with a nonlinear static gain. Second, a feedforward neural network is proposed to formulate the traditional PID controller, termed as PID-type neural network (PIDNN), which is then used to control and compensate for the DZC. In this way, the DC motor system with DZC is identified by the WNN identifier, which provides model information to the PIDNN controller in order to make it adaptive. Back-propagation algorithms are used to train both neural networks. Also, stability and convergence analysis are conducted using the Lyapunov theorem. Finally, experiments on the DC motor system demonstrated accurate identification and good compensation for dead-zone with improved control performance over the conventional PID control. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  10. PID Fuzzy Logic Controller System for DC Motor Speed Control

    Directory of Open Access Journals (Sweden)

    H Samsul Bachri

    2010-10-01

    Full Text Available A good controller system must have resilience to disturbance and must be able to response quickly and accurately. Problem usually appears when PID controller system was built sensitively hence the system's respon to the disturbance will yield big overshot/undershot then the possibility of  oscillation to be happened is excelsior. When the controller system was built insensitively, the overshot/undershot will be  small but the recovery time will be longer. Hybrid controller system could overcome those problems by combining PID control system with fuzzy logic. The main control of this system is PID controller while the fuzzy logic acts to reduce an overshot/undershot and a recovery time. The fuzzy logic controller is designed with two input error and delta error and one output of the motor speed. The output of fuzzy logic controller should be only half of the PID controller for limiting entirely fuzzy output. This hybrid system design has a better respon time controller system than PID controller without fuzzy logic.

  11. A Design Study of Dual-Stator Permanent Magnet Brushless DC Motor

    Directory of Open Access Journals (Sweden)

    Yanliang Xu

    2013-11-01

    Full Text Available Dual-stator permanent magnet brushless DC Motor (DSBLDC features high efficiency and torque-density. As DSBLDC could operate in various states according to different winding connection modes, it is fully qualified for electric vehicle (EV drive. Unfortunately, due to the particular dual-stator structure, this kind of motor is difficult to be designed by available design methods. However, this paper demonstrates that a DSBLDC with series magnetic circuit structure can be regarded as being consisted of two independent BLDCs, i.e. an inner-rotor BLDC and an outer-rotor BLDC. Thus, the DSBLDC can be divided into two single-stator BLDCs. Based on this demonstration, the design method is verified by finite element analysis (FEA, and the basic design steps are given. Furthermore, experimental results of the prototype motor have verified the correction of the method, which also indicates that the motor with superior performance is adapted to EV drive.

  12. Four quadrant control circuit for a brushless three-phase dc motor

    Science.gov (United States)

    Nola, Frank J. (Inventor)

    1987-01-01

    A control circuit is provided for a brushless three-phase dc motor which affords four quadrant control from a single command. The control circuit probes acceleration of the motor in both clockwise and counterclockwise directions and braking and generation in both clockwise and counterclockwise directions. In addition to turning on individual transistors of the transistor pairs connected to the phase windings of the motor for 120 deg periods while the other transistor of that pair is off, the control circuit also provides, in a future mode of operation, turning the two transistors of each pair on and off alternately at a phase modulation frequency during such a 120 deg period. A feedback signal is derived which is proportional to the motor current and which has a polarity consistent with the command signal, such that negative feedback results.

  13. Genetic algorithm based design optimization of a permanent magnet brushless dc motor

    Science.gov (United States)

    Upadhyay, P. R.; Rajagopal, K. R.

    2005-05-01

    Genetic algorithm (GA) based design optimization of a permanent magnet brushless dc motor is presented in this paper. A 70 W, 350 rpm, ceiling fan motor with radial-filed configuration is designed by considering the efficiency as the objective function. Temperature-rise and motor weight are the constraints and the slot electric loading, magnet-fraction, slot-fraction, airgap, and airgap flux density are the design variables. The efficiency and the phase-inductance of the motor designed using the developed CAD program are improved by using the GA based optimization technique; from 84.75% and 5.55 mH to 86.06% and 2.4 mH, respectively.

  14. Numerical and Experimental Investigation of Heat Flow in Permanent Magnet Brushless DC Hub Motor

    DEFF Research Database (Denmark)

    Fasil, Muhammed; Plesner, Daniel; Walther, Jens Honore

    2014-01-01

    This paper investigates the heat dissipation in the hub motor of an electric two-wheeler using lumped parameter (LP), finite element (FE) and computational fluid dynamic (CFD) models. The motor uses external rotor permanent magnet brushless DC topology and nearly all of its losses are generated...... in the stator. The hub motor construction restricts the available conductive paths for heat dissipation from the stator to the ambient only through the shaft. In contrast to an internal rotor structure, where the stator winding losses are diffused via conduction, here convection plays a major role in loss...... dissipation. Therefore, a LP thermal model with improved convection modelling has been proposed to calculate the temperature of the components inside the hub motor. The developed model is validated with the FE thermal model and the test data. In addition, CFD tools has been used to accurately model...

  15. A vector modulated three-phase four-quadrant rectifier - Application to a dc motor drive

    Energy Technology Data Exchange (ETDEWEB)

    Jussila, Matti; Salo, Mika; Kaehkoenen, Lauri; Tuusa, Heikki

    2004-07-01

    This paper introduces a theory for a space vector modulation of a three-phase four-quadrant PWM rectifier (FQR). The presented vector modulation method is simple to realize with a microcontroller and it replaces the conventional modulation methods based on the analog technology. The FQR may be used to supply directly a dc load, e.g. a dc machine. The vector modulated FQR is tested in simulations supplying a 4.5 kW dc motor. The simulations show the benefits of the vector modulated FQR against thyristor converters: the supply currents are sinusoidal and the displacement power factor of the supply can be controlled. Furthermore the load current is smooth. (author)

  16. Estimation parameters and black box model of a brushless DC motor

    Directory of Open Access Journals (Sweden)

    José A. Becerra-Vargas

    2014-08-01

    Full Text Available The modeling of a process or a plant is vital for the design of its control system, since it allows predicting its dynamic and behavior under different circumstances, inputs, disturbances and noise. The main objective of this work is to identify which model is best for a permanent magnet brushless DC specific motor. For this, the mathematical model of a DC motor brushless PW16D, manufactured by Golden Motor, is presented and compared with its black box model; both are derived from experimental data. These data, the average applied voltage and the angular velocity, are acquired by a data acquisition card and imported to the computer. The constants of the mathematical model are estimated by a curve fitting algorithm based on non-linear least squares and pattern search using computational tool. To estimate the mathematical model constants by non-linear least square and search pattern, a goodness of fit of 84.88% and 80.48% respectively was obtained. The goodness of fit obtained by the black box model was 87.72%. The mathematical model presented slightly lower goodness of fit, but allowed to analyze the behavior of variables of interest such as the power consumption and the torque applied to the motor. Because of this, it is concluded that the mathematical model obtained by experimental data of the brushless motor PW16D, is better than its black box model.

  17. POSITION CONTROL OF BRUSHLESS DC MOTOR BASED ON DIGITAL SIGNAL PROCESSING

    Directory of Open Access Journals (Sweden)

    Çetin GENÇER

    2006-01-01

    Full Text Available Brushless DC Motors (BLDC have been used widely high performance control systems which are depended on to development of power electronic and control technology. In these motors to fed commutated supply, the control of position without oscilation has been required. In this study, position control of BLDC with digital signal processing has been implemented by a proportional-derivative (PD controller because of its simple structure. It has been seen that the controller which is proposed from simulation and experimental studies, has a quick dynamic responce with nonoscillation.

  18. Novel Position and Speed Estimator for PM Single Phase Brushless D.C. Motor Drives

    DEFF Research Database (Denmark)

    Lepure, Liviu I.; Andreescu, Gheorghe-Daniel; Iles, Doris

    2010-01-01

    A novel position and speed estimator for single phase permanent magnet brushless d.c. (PMBLDC) motor drives, based on flux integration and prior knowledge of ΨPM (θ) is proposed here and an adequate correction algorithm is adopted in order to increase the robustness to noise and to reduce...... the sensitivity to accuracy of flux linkage estimation. A speed and current close loop control is employed based on the Hall signal and the motor is controlled at different speeds in order to validate the proposed estimation algorithm with satisfying results. The position correction effect is analyzed...

  19. Demonstrative fractional order - PID controller based DC motor drive on digital platform.

    Science.gov (United States)

    Khubalkar, Swapnil W; Junghare, Anjali S; Aware, Mohan V; Chopade, Amit S; Das, Shantanu

    2017-09-21

    In industrial drives applications, fractional order controllers can exhibit phenomenal impact due to realization through digital implementation. Digital fractional order controllers have created wide scope as it possess the inherent advantages like robustness against the plant parameter variation. This paper provides brief design procedure of fractional order proportional-integral-derivative (FO-PID) controller through the indirect approach of approximation using constant phase technique. The new modified dynamic particle swarm optimization (IdPSO) technique is proposed to find controller parameters. The FO-PID controller is implemented using floating point digital signal processor. The building blocks are designed and assembled with all peripheral components for the 1.5kW industrial DC motor drive. The robust operation for parametric variation is ascertained by testing the controller with two separately excited DC motors with the same rating but different parameters. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Intelligent Controller Design for DC Motor Speed Control based on Fuzzy Logic-Genetic Algorithms Optimization

    OpenAIRE

    Allaoua, Boumediene; Laoufi, Abdellah; Gasbaoui, Brahim; Abdelfatah NASRI; Abdessalam ABDERRAHMANI

    2008-01-01

    In this paper, an intelligent controller of the DC (Direct current) Motor drive is designed using fuzzy logic-genetic algorithms optimization. First, a controller is designed according to fuzzy rules such that the systems are fundamentally robust. To obtain the globally optimal values, parameters of the fuzzy controller are improved by genetic algorithms optimization model. Computer MATLAB work space demonstrate that the fuzzy controller associated to the genetic algorithms approach became ve...

  1. speed control of dc motor on load using fuzzy logic controller

    African Journals Online (AJOL)

    HP

    This paper presents the development of a fuzzy logic controller for the driver DC motor in the lube oil system of the H25. Hitachi gas turbine generator. The turbine generator is required to run at an operating pressure of 1.5bar with the low and the high pressure trip points being 0.78 bar and 1.9 bar respectively. However ...

  2. Adaptive Neuro-Fuzzy Controller Experimental Design for DC Motor Connected to Unbalanced Load

    OpenAIRE

    Reza Nejati; Rahmat Hooshamnd

    2007-01-01

    In two recent decades, fuzzy controllers have been used in controlling different systems successfully. In this article, a new method is given for controlling of permanent magnetic DC motor connected to unbalanced load. Imbalance of load leads to machine vibrations, fluctuation of power, making exhaustion in machine shaft, and equipment depreciation. In this article neuro-fuzzy controllers are used for controlling unbalanced load. Because of non-linear nature of load and machine, machine fluct...

  3. speed control of dc motor on load using fuzzy logic controller

    African Journals Online (AJOL)

    This paper presents the development of a fuzzy logic controller for the driver DC motor in the lube oil system of the H25 Hitachi gas turbine generator. The turbine generator is required to run at an operating pressure of 1.5bar with the low and the high pressure trip points being 0.78 bar and 1.9 bar respectively. However, the ...

  4. The Impact of Grid Unbalances on the Reliability of DC-link Capacitors in a Motor Drive

    DEFF Research Database (Denmark)

    Wang, Huai; Davari, Pooya; Kumar, Dinesh

    2017-01-01

    and ripple currents are presented. The relationship between the DC-link capacitor lifetime and the level of unbalances and loads are discussed based on a 7.5 kW motor drive system. The results serve as a guideline to size the DC-link capacitors to be robust enough at the presence of grid unbalance conditions.......DC-link capacitor is one of the reliability-critical components in motor drive applications, which contributes to a considerable cost, size and failure. Its reliability performance depends on both inherent physical strength and external loading. The grid unbalances could alter the electro......-thermal stresses of key components in a motor drive. Therefore, this digest investigates the impact of grid voltage amplitude and phase unbalances on the lifetime of DC-link capacitors used in a standard three-phase motor drive. The theoretical stress models and experimental measurements of the capacitor voltages...

  5. A Modified High-Efficient Step-Up Sepic for DC Motor Drives

    Directory of Open Access Journals (Sweden)

    P. Dhanasekaran

    2013-12-01

    Full Text Available In this paper, Single-Ended Primary Inductor Converter (SEPIC fed DC motor is proposed. Soft-switching technique such as Zero-Voltage-Switching (ZVS and Zero-Current-Switching (ZCS operation plays a vital role in high voltage applications. Zero-Current-Switching (ZCS operation achieved due to resonance between the resonant inductor and the capacitor by using output diode and its reverse-recovery loss is subsequently reduced. Zero-Voltage-Switching (ZVS operation is achieved by using coupled inductor and auxiliary inductor. The model has been simulated through MATLAB/SIMULINK using Diode Bridge, SEPIC topology and closed loop DC motor load and it is modeled analytically. The proposed system is modeled with input side Diode Bridge Rectifier and SEPIC Topology with Proportional Integral (PI controller. The soft switching scheme for the proposed topology is developed with closed loop motor load. The motor voltage is achieved twice the rated voltage. The results are generated in MATLAB/SIMULINK and are shown.

  6. Primary control of a Mach scale swashplateless rotor using brushless DC motor actuated trailing edge flaps

    Science.gov (United States)

    Saxena, Anand

    The focus of this research was to demonstrate a four blade rotor trim in forward flight using integrated trailing edge flaps instead of using a swashplate controls. A compact brushless DC motor was evaluated as an on-blade actuator, with the possibility of achieving large trailing edge flap amplitudes. A control strategy to actuate the trailing edge flap at desired frequency and amplitude was developed and large trailing edge flap amplitudes from the motor (instead of rotational motion) were obtained. Once the actuator was tested on the bench-top, a lightweight mechanism was designed to incorporate the motor in the blade and actuate the trailing edge flaps. A six feet diameter, four bladed composite rotor with motor-flap system integrated into the NACA 0012 airfoil section was fabricated. Systematic testing was carried out for a range of load conditions, first in the vacuum chamber followed by hover tests. Large trailing edge flap deflections were observed during the hover testing, and a peak to peak trailing edge flap amplitude of 18 degree was achieved at 2000 rotor RPM with hover tip Mach number of 0.628. A closed loop controller was designed to demonstrate trailing edge flap mean position and the peak to peak amplitude control. Further, a soft pitch link was designed and fabricated, to replace the stiff pitch link and thereby reduce the torsional stiffness of the blade to 2/rev. This soft pitch link allowed for blade root pitch motion in response to the trailing edge flap inputs. Blade pitch response due to both steady as well as sinusoidal flap deflections were demonstrated. Finally, tests were performed in Glenn L. Martin wind tunnel using a model rotor rig to assess the performance of motor-flap system in forward flight. A swashplateless trim using brushless DC motor actuated trailing edge flaps was achieved for a rotor operating at 1200 RPM and an advance ratio of 0.28. Also, preliminary exploration was carried out to test the scalability of the motor

  7. On-Line Tracking Controller for Brushless DC Motor Drives Using Artificial Neural Networks

    Science.gov (United States)

    Rubaai, Ahmed

    1996-01-01

    A real-time control architecture is developed for time-varying nonlinear brushless dc motors operating in a high performance drives environment. The developed control architecture possesses the capabilities of simultaneous on-line identification and control. The dynamics of the motor are modeled on-line and controlled using an artificial neural network, as the system runs. The control architecture combines the experience and dependability of adaptive tracking systems with potential and promise of the neural computing technology. The sensitivity of real-time controller to parametric changes that occur during training is investigated. Such changes are usually manifested by rapid changes in the load of the brushless motor drives. This sudden change in the external load is simulated for the sigmoidal and sinusoidal reference tracks. The ability of the neuro-controller to maintain reasonable tracking accuracy in the presence of external noise is also verified for a number of desired reference trajectories.

  8. Torque ripple reduction of brushless DC motor based on adaptive input-output feedback linearization.

    Science.gov (United States)

    Shirvani Boroujeni, M; Markadeh, G R Arab; Soltani, J

    2017-09-01

    Torque ripple reduction of Brushless DC Motors (BLDCs) is an interesting subject in variable speed AC drives. In this paper at first, a mathematical expression for torque ripple harmonics is obtained. Then for a non-ideal BLDC motor with known harmonic contents of back-EMF, calculation of desired reference current amplitudes, which are required to eliminate some selected harmonics of torque ripple, are reviewed. In order to inject the reference harmonic currents to the motor windings, an Adaptive Input-Output Feedback Linearization (AIOFBL) control is proposed, which generates the reference voltages for three phases voltage source inverter in stationary reference frame. Experimental results are presented to show the capability and validity of the proposed control method and are compared with the vector control in Multi-Reference Frame (MRF) and Pseudo-Vector Control (P-VC) method results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  9. APPLICATION FEATURES OF FUZZY CONTROLLERS ON EXAMPLE OF DC MOTOR SPEED CONTROL

    Directory of Open Access Journals (Sweden)

    G. L. Demidova

    2016-09-01

    Full Text Available A prerequisite for the use of intelligent control methods, including algorithms of fuzzy logic, is increasing complexity in all industries, especially when parameters of technical systems while in operation vary in wide range. The paper provides comparative analysis of the basic types of common fuzzy direct action controllers on the example of speed control system in the DC motor drive. Design features of these types of fuzzy controllers are shown. Their comparison with traditional PI controller is carried out through the use of simulation, including the conditions of uncertainty expressed in changing of equivalent moment of inertia of the motor shaft. As a result, the conclusion about the feasibility of fuzzy PID-type controller application is made. The features of fuzzy controllers outlined in the paper can be summarized to more complex motor drive systems and to other non-linear systems that require the maintenance of any parameter within a given range.

  10. Soft-commutated direct current motor

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, J.S.

    1999-07-27

    A method and circuit is disclosed for soft-commutation of a direct current (DC) motor. An attenuation circuit is connected through auxiliary brushes A, A[prime], B and B[prime] to the commutator (16) to drain circuit from successive armature coils (15) before the main brushes (27, 28) disconnects from each of the coils (15). This prevents the spark generation that normally occurs in conventional DC motors. The attenuation circuit may also be connected before energization of the coil (15) for a soft turning on operation. 13 figs.

  11. Soft-commutated direct current motor

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, John S. (Oak Ridge, TN)

    1999-01-01

    A method and circuit is disclosed for soft-commutation of a direct current (DC) motor. An attenuation circuit is connected through auxiliary brushes A, A', B and B' to the commutator (16) to drain circuit from successive armature coils (15) before the main brushes (27, 28) disconnects from each of the coils (15). This prevents the spark generation that normally occurs in conventional DC motors. The attenuation circuit may also be connected before energization of the coil (15) for a soft turning on operation.

  12. The Impact of Grid Unbalances on the Reliability of DC-link Capacitors in a Motor Drive

    DEFF Research Database (Denmark)

    Wang, Huai; Davari, Pooya; Kumar, Dinesh

    2017-01-01

    DC-link capacitor is one of the reliability-critical components in motor drive applications, which contributes to a considerable cost, size and failure. Its reliability performance depends on both inherent physical strength and external loading. The grid unbalances could alter the electro...... and ripple currents are presented. The relationship between the DC-link capacitor lifetime and the level of unbalances and loads are discussed based on a 7.5 kW motor drive system. The results serve as a guideline to size the DC-link capacitors to be robust enough at the presence of grid unbalance conditions....

  13. Electric motors and drives. Pt. 15. D.c. motors. Part 1; Elektrische Maschinen und Antriebe. T. 15. Gleichstrommaschinen. T. 1

    Energy Technology Data Exchange (ETDEWEB)

    Biechl, H. [Werner-von-Siemens-Labor fuer Elektrische Antriebe und Mechatronik, Hochschule Kempten (Germany)

    2008-07-15

    This first contribution on d.c. motors starts by describing a very simple motor to illustrate its functional principle. The commutator, the starting and idle speed conditions are described. Some equations and characteristics are presented to illustrate the operating characteristics. (orig.)

  14. Efficiency consideration of DC link soft-switching inverters for motor drive applications

    Energy Technology Data Exchange (ETDEWEB)

    Lai, J.S.; Young, R.W.; McKeever, J.W.

    1994-12-31

    This paper critically evaluates efficiency of soft switching inverters including an actively clamped resonant dc link inverter and a clamped-mode resonant pole inverter. An analytical approach to evaluating efficiency of the clamped-mode soft switching inverter has been developed. The evaluation results are compared with that of the standard pulse-width-modulation (PWM) inverter. A 50-kW induction motor is used as the variable load, and the inverter efficiency is evaluated under different speed and torque conditions. The clamped-mode soft-switching inverter, although eliminating the switching loss, shows poor efficiency over the entire load range. Under low load conditions, the efficiency profile is even worse. The actively clamped resonant dc link inverter shows highest efficiency over the entire speed and torque range. However, its energy saving over the standard PWM inverter is marginal under full load or high speed conditions.

  15. Efficiency consideration of DC link soft-switching inverters for motor drive applications

    Science.gov (United States)

    Lai, J. S.; Young, R. W.; McKeever, J. W.

    ?his paper critically evaluates efficiency of soft switching inverters including an actively clamped resonant DC link inverter and a clamped-mode resonant pole inverter. An analytical approach to evaluating efficiency of the clamped-mode soft switching inverter has been developed. The evaluation results are compared with that of the standard pulse-width-modulation (PWM) inverter. A 50-kW induction motor is used as the variable load, and the inverter efficiency is evaluated under different speed and torque conditions. The clamped-mode soft-switching inverter, although eliminating the switching loss, shows poor efficiency over the entire load range. Under low load conditions, the efficiency profile is even worse. The actively clamped resonant DC link inverter shows highest efficiency over the entire speed and torque range. However, its energy saving over the standard PWM inverter is marginal under full load or high speed conditions.

  16. Test Platform for Advanced Digital Control of Brushless DC Motors (MSFC Center Director's Discretionary Fund)

    Science.gov (United States)

    Gwaltney, D. A.

    2002-01-01

    A FY 2001 Center Director's Discretionary Fund task to develop a test platform for the development, implementation. and evaluation of adaptive and other advanced control techniques for brushless DC (BLDC) motor-driven mechanisms is described. Important applications for BLDC motor-driven mechanisms are the translation of specimens in microgravity experiments and electromechanical actuation of nozzle and fuel valves in propulsion systems. Motor-driven aerocontrol surfaces are also being utilized in developmental X vehicles. The experimental test platform employs a linear translation stage that is mounted vertically and driven by a BLDC motor. Control approaches are implemented on a digital signal processor-based controller for real-time, closed-loop control of the stage carriage position. The goal of the effort is to explore the application of advanced control approaches that can enhance the performance of a motor-driven actuator over the performance obtained using linear control approaches with fixed gains. Adaptive controllers utilizing an exact model knowledge controller and a self-tuning controller are implemented and the control system performance is illustrated through the presentation of experimental results.

  17. Developing micro DC-brushless motor driver and position control for fiber positioners

    Science.gov (United States)

    Jenni, Laurent; Hörler, Philipp; Makarem, Laleh; Kneib, Jean-Paul; Gillet, Denis; Bleuler, Hannes; Bouri, Mohamed; Prada, Francisco; De Rivera, Guillermo; Sanchez, Justo

    2014-07-01

    In the large-scale, Dark Energy Spectroscopic Instrument (DESI), thousands of fiber positioners will be used. Those are robotic positioners, with two axis, and having the size of a pen. They are tightly packed on the focal plane of the telescope. Dedicated micro-robots have been developed and they use 4mm brushless DC motors. To simplify the implementation and reduce the space occupancy, each actuator will integrate its own electronic control board. This board will be used to communicate with the central trajectory generator, manage low level control tasks and motor current feeding. In this context, we present a solution for a highly compact electronic. This electronic is composed of two layers. The first is the power stage that can drive simultaneously two brushless motors. The second one consists of a fast microcontroller and deals with different control tasks: communication, acquisition of the hall sensor signals, commutation of the motors phases, and performing position and current regulation. A set of diagnostic functions are also implemented to detect failure in the motors or the sensors, and to sense abnormal load change that may be the result of two robots colliding.

  18. Analysis of Electric Propulsion Performance on Submersible with Motor DC, Supply Power 10260AH at Voltage 115VDC

    Directory of Open Access Journals (Sweden)

    Indra Ranu Kusuma

    2017-03-01

    Full Text Available Electric propulsion is the ship system using propulsion motor to replace performance of main engine. The application of diesel engine as propulsion system have some problems and weaknesses such as diesel engine unability to operate when submersible vessel is operating under sea. To overcome that problems in submersible vessel, alternative solution of ship propulsion is required. DC Motor can be used as this alternative solution. Submersible vessel use electric propulsion system with DC Motor because DC Motor has advantages of easy rotation setting and does not cause noise when submersible vessel is diving. This bachelor thesis will study the application of DC Motor as an electric propulsion system on submersible vessel with length 59,57 m in series and parallel circuit by simulation using MATLAB software. The simulation data obtained are rotation and torque of DC Motor. From these simulation, it can be concluded that parallel circuit rotation is greater than series circuit rotation. It caused the greater speed and lower power in parallel circuit. 

  19. Spin coater based on brushless dc motor of hard disk drivers.

    OpenAIRE

    Bianchi, Rodrigo Fernando; Panssiera, M. F.; Lima, J. P. H.; Yagura, L.; Andrade, A. M.; Faria, Roberto Mendonça

    2006-01-01

    We have developed a novel programmable, low cost, spin coater to be used for applications where flat substrates are coated with an uniform thin layer of a desirable material. The equipment is built with dc brushless motor present in most of the hard disk drivers (HDDs). The system offers manual control, wide speed range (from 0 to 10,000 rpm), spin speed stability and compact size. The paper also describes the use of such equipment for the fabrication of thin poly(o-methoxyaniline) (POMA) fil...

  20. Extended Constant Power Speed Range of the Brushless DC Motor Through Dual Mode Inverter Control

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, J.S.

    2000-06-23

    The trapezoidal back electromotive force (emf) brushless direct current (dc) motor (BDCM) with surface-mounted magnets has high-power density and efficiency especially when rare-earth magnet materials are used. Traction applications, such as electric vehicles, could benefit significantly from the use of such motors. Unfortunately, a practical means for driving the motor over a constant power speed ratio (CPSR) of 5:1 or more has not yet been developed. A key feature of these motors is that they have low internal inductance. The phase advance method is effective in controlling the motor power over such a speed range, but the current at high speed may be several times greater than that required at the base speed. The increase in current during high-speed operation is due to the low motor inductance and the action of the bypass diodes of the inverter. The use of such a control would require increased current rating of the inverter semiconductors and additional cooling for the inverter, where the conduction losses increase proportionally with current, and especially for the motor, where the losses increase with the square of the current. The high current problems of phase advance can be mitigated by adding series inductance; however, this reduces power density, requires significant increase in supply voltage, and leaves the CPSR performance of the system highly sensitive to variations in the available voltage. A new inverter topology and control scheme has been developed that can drive low-inductance BDCMs over the CPSR that would be required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC). It is shown that the BDCM has an infinite CPSR when it is driven by the DMIC.

  1. DC Motor Drive for Small Autonomous Robots with Educational and Research Purpose

    Science.gov (United States)

    Krklješ, Damir; Babković, Kalman; Nagy, László; Borovac, Branislav; Nikolić, Milan

    Many student robot competitions have been established during the last decade. One of them, and the most popular in Europe, is the European competition EUROBOT. The basic aim of this competition is to promote the robotics among young people, mostly students and high school pupils. The additional outcome of the competition is the development of faculty curriculums that are based on this competition. Such curriculum has been developed at the Faculty of Technical Science in Novi Sad. The curriculum duration is two semesters. During the first semester the theoretical basis is presented to the students. During the second semester the students, divided into teams of three to five students, develop the robots which will take part in the incoming EUROBOT competition. Since the time for the robot development is short, the basic electronic kit is provided for the students. The basic parts of the kit are two DC motor drives dedicated to the robot locomotion. The drives will also be used in the research concerning the multi segment robot foot. This paper presents the DC motor drive and its features. The experimental results concerning speed and position regulations and also the current limiting is presented too.

  2. DC Brushless Motor Control Design and Preliminary Testing for Independent 4-Wheel Drive Rev-11 Robotic Platform

    Directory of Open Access Journals (Sweden)

    Roni Permana Saputra

    2012-03-01

    Full Text Available This paper discusses the design of control system for brushless DC motor using microcontroller ATMega 16 that will be applied to an independent 4-wheel drive Mobile Robot LIPI version 2 (REV-11. The control system consists of two parts which are brushless DC motor control module and supervisory control module that coordinates the desired command to the motor control module. To control the REV-11 platform, supervisory control transmit the reference data of speed and direction of motor to control the speed and direction of each actuator on the platform REV-11. From the test results it is concluded that the designed control system work properly to coordinate and control the speed and direction of motion of the actuator motor REV-11 platform. 

  3. Performances Comparison of Permanent Magnet Brushless DC and Doubly Salient Reluctance Motors for an Urban Electric Vehicle

    OpenAIRE

    Multon, Bernard; Hoang, Emmanuel; Camus, François

    1993-01-01

    International audience; In this paper, we carried out a dimensional parametric analysis of average torque and copper losses in the case of two synchronous brushless motors. These motors were, on the one hand, a Permanent-Magnet Brushless DC (PMBLDC) motor supplied by quasi-square currents, with surface magnet mounted rotor and trapezoidal e.m.f. waveform, and, on the other hand, a Doubly Salient Variable Reluctance (DSVR) motor fed by quasi-square currents at low speed, and by full wave squar...

  4. Capacitance Estimation Algorithm based on DC-Link Voltage Harmonics Using ANN in Three-Phase Motor Drive Systems

    DEFF Research Database (Denmark)

    Soliman, Hammam Abdelaal Hammam; Davari, Pooya; Wang, Huai

    2017-01-01

    to industry. In this digest, a condition monitoring methodology that estimates the capacitance value of the dc-link capacitor in a three phase Front-End diode bridge motor drive is proposed. The proposed software methodology is based on Artificial Neural Network (ANN) algorithm. The harmonics of the dc......-link voltage are used as training data to the Artificial Neural Network. Fast Fourier Transform (FFT) of the dc-link voltage is analysed in order to study the impact of capacitance variation on the harmonics order. Laboratory experiments are conducted to validate the proposed methodology and the error analysis...

  5. Highlighting the harmonic regime generated by electric locomotives equipped with DC motors

    Science.gov (United States)

    Baciu, I.; Cunţan, C. D.

    2018-01-01

    The paper presents the results of measurements made using the C.A. 8334 power quality analyzer on an electric locomotive equipped with DC motors. We carried out determinations of the current-voltage regime using a locomotive motor. The harmonic regime of the other motors being identical to the analysed one, we could easily deduce the effects caused by the entire locomotive. The data measured with the analyzer were firstly transferred into a computer system using the Qualistar software, followed by data processing in Excel, enabling therefore a graphical representation of the characteristic parameters of power quality. Based on the acquired data, we determined the power factor, as well as the active, reactive and apparent power. The measurements revealed high values of the current harmonics, fact that required some measures to be taken for reducing the values of these harmonics. For this, we ran a simulation using the PSCAD/EMTDC software, by introducing LC filters in tune with the harmonic frequencies. The result was a significant reduction in the harmonic regime, either in the harmonics values or the power factor and reactive power.

  6. Real Time Implementation of a DC Motor Speed Control by Fuzzy Logic Controller and PI Controller Using FPGA

    Directory of Open Access Journals (Sweden)

    G. Sakthivel

    2010-10-01

    Full Text Available Fuzzy logic control has met with growing interest in many motor control applications due to its non-linearity, handling features and independence of plant modelling. The hardware implementation of fuzzy logic controller (FLC on FPGA is very important because of the increasing number of fuzzy applications requiring highly parallel and high speed fuzzy processing. Implementation of a fuzzy logic controller and conventional PI controller on an FPGA using VHDL for DC motor speed control is presented in this paper. The proposed scheme is to improve tracking performance of D.C. motor as compared to the conventional (PI control strategy .This paper describes the hardware implementation of two inputs (error and change in error, one output fuzzy logic controller based on PI controller and conventional PI controller using VHDL. Real time implementation FLC and conventional PI controller is made on Spartan-3A DSP FPGA (XC3SD1800A FPGA for the speed control of DC motor. It is observed that fuzzy logic based controllers give better responses than the conventional PI controller for the speed control of dc motor.

  7. Proper Brushing

    Science.gov (United States)

    ... both the tooth surface and the gumline. Gently brush the outer tooth surfaces of 2-3 teeth using a vibrating ... along all of the inner tooth surfaces. Tilt brush vertically behind the front teeth. Make several up & down strokes using the front ...

  8. A Comparison Between Fuzzy-PSO Controller and PID-PSO Controller for Controlling a DC Motor

    OpenAIRE

    Ghareaghaji, Ali

    2015-01-01

    The Direct current motors are in different types and there are several methods for controlling of their speed. In this paper two ways for speed controlling suggested. First a fuzzy logic speed controller for DC motor is designed and it's parameter calculated by Particle Sward Optimization (PSO). The speed controller designed according to fuzzy rules, then for having better performance, the controller optimized with PSO. Secondly a PID controller that it's parameter find by PSO, is used for sp...

  9. Speed Digital Control of Brushless DC Motor Using dsPIC Controller

    Directory of Open Access Journals (Sweden)

    Gheorghe Băluţă

    2014-09-01

    Full Text Available This paper presents the digital control of the Brushless DC motor (BLDCM speed. The dsPICDEM MC1 development system (with the dsPIC30F6010A microcontroller and the dsPICDEM MC1L power module, manufactured by Microchip Company, were used. The control program was developed in C programming language. The graphical user interface was realized in LabVIEW 8.6 graphical programming language. For speed control, a digital controller PI type was implemented. Due to digital controller well chosen and well tuned, the system response at speed step variation is very good. Therewith, the experimental results obtained also show a good compensation of disturbance which does not happen in open-loop control.

  10. Dynamic modeling of brushless dc motor-power conditioner unit for electromechanical actuator application

    Science.gov (United States)

    Demerdash, N. A.; Nehl, T. W.

    1979-01-01

    A comprehensive digital model for the analysis of the dynamic-instantaneous performance of a power conditioner fed samarium-cobalt permanent magnet brushless DC motor is presented. The particular power conditioner-machine system at hand, for which this model was developed, is a component of an actual prototype electromechanical actuator built for NASA-JSC as a possible alternative to hydraulic actuators as part of feasibility studies for the shuttle orbiter applications. Excellent correlation between digital simulated and experimentally obtained performance data was achieved for this specific prototype. This is reported on in this paper. Details of one component of the model, its applications and the corresponding results are given in this paper.

  11. Dynamic Characteristic Analysis of Linear DC Motor by 3D EMCN Considering Input Voltage

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Kyung Ho; Yeom, Sang Bu [Changwon National University, Changwon(Korea); Hong, JUNG Pyo; Hur Jin; Kang Do Hyunc [Hanyang University(Seoul Campus), Seoul(Korea)

    2002-02-01

    In order to design the Linear DC Motor (LDM) With improved characteristics, transient and steady state analysis are required. Furthermore, 3D analysis is also needed to analyze the precise characteristics like thrust, time harmonics. This paper deals with the transient and dynamic characteristic analysis if LDM by coupling of external circuit and motion equation using 3D Equivalent Magnetic Circuit Network Method (EMCN). For the three dimensional analysis of electric machine, EMCN is very effective method that ensures high accuracy similar to FEM and short computation time. Also, The modeling by EMCN easily allows the mover to move with respect to the Sartre at each time Also, and the spatial moving step is determined by the solution of the mechanical motion equation and the computed electromagnetic thrust. The results are compared with experimental ones to clarify the usefulness and verify the accuracy of the proposed method. (author). 11 refs., 20 figs., 2 tabs.

  12. Harmonic Mitigation using 36-Pulse AC-DC Converter for Direct Torque Controlled Induction Motor Drives

    Directory of Open Access Journals (Sweden)

    R. Abdollahi

    2015-02-01

    Full Text Available This paper presents the design and analysis of a transformer based 36-pulse ac-dc converters which supplies direct torque controlled induction motor drives (DTCIMD's in order to have better power quality conditions at the point of common coupling. The converters output voltage is accomplished via two paralleled eighteen-pulse ac-dc converters each of them consisting of nine-phase diode bridge rectifier. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. The 36-pulse structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse and 36-pulse converters (Polygon, Fork, and Hexagon from view point of power quality indices. Results show that input current total harmonic distortion (THD is less than 4% for the 36-pulse topologies at variable loads. The Delta/Hexagon connected platform could simplify the resulted configuration for the converters and reducing the costs.

  13. POWER FACTOR CORRECTION IN PERMANENT MAGNET BRUSHLESS DC MOTOR DRIVE USING SINGLE-PHASE CUK CONVERTER

    Directory of Open Access Journals (Sweden)

    SANJEEV SINGH

    2010-12-01

    Full Text Available Permanent magnet brushless DC motor (PMBLDCM drives are being employed in many variable speed applications due to their high efficiency, silent operation, compact size, high reliability, ease of control, and low maintenance requirements. These drives have power quality problems and poor power factor at input AC mains as they are mostly fed through diode bridge rectifier based voltage source inverters. To overcome such problems a single-phase single-switch power factor correction AC-DC converter topology based on a Cuk converter is proposed to feed voltage source inverters based PMBLDCM. It focuses on the analysis, design and performance evaluation of the proposed PFC converter topology for a 1.5 kW, 1500 rpm, 400 V PMBLDCM drive used for an air-conditioning system. The proposed PFC converter topology is modelled and its performance is simulated in Matlab-Simulink environment and results show an improved power quality and good power factor in wide speed range of the drive.

  14. Novel Sensorless Six-Step Communication Strategy for a Surface Permanent Magnet Synchronous Motor with DC Link Measurement

    DEFF Research Database (Denmark)

    Munteanu, A.; Agarlita, S. C.; Blaabjerg, Frede

    2012-01-01

    The present paper introduces a novel six-step commutation strategy for sensorless control applied for a surface permanent magnet synchronous motor that implies only dc link measurement (battery current and battery voltage). The control strategy makes use of a modified I-f starting procedure...

  15. The Effect of Distributed Parameters on Conducted EMI from DC-Fed Motor Drive Systems in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Li Zhai

    2016-12-01

    Full Text Available The large dv/dt and di/dt outputs of power devices in DC-fed motor drive systems in electric vehicles (EVs always introduce conducted electromagnetic interference (EMI emissions and may lead to motor drive system energy transmission losses. The effect of distributed parameters on conducted EMI from the DC-fed high voltage motor drive systems in EVs is studied. A complete test for conducted EMI from the direct current fed(DC-fed alternating current (AC motor drive system in an electric vehicle (EV under load conditions is set up to measure the conducted EMI of high voltage DC cables and the EMI noise peaks due to resonances in a frequency range of 150 kHz–108 MHz. The distributed parameters of the motor can induce bearing currents under low frequency sine wave operation. However the impedance of the distributed parameters of the motor is very high at resonance frequencies of 500 kHz and 30 MHz, and the effect of the bearing current can be ignored, so the research mainly focuses on the distributed parameters in inverters and cables at 500 kHz and 30 MHz, not the effect of distributed parameters of the motor on resonances. The corresponding equivalent circuits for differential mode (DM and common mode (CM EMI at resonance frequencies of 500 kHz and 30 MHz are established to determine the EMI propagation paths and analyze the effect of distributed parameters on conducted EMI. The dominant distributed parameters of elements responsible for the appearing resonances at 500 kHz and 30 MHz are determined. The effect of the dominant distributed parameters on conducted EMI are presented and verified by simulation and experiment. The conduced voltage at frequencies from 150 kHz to 108 MHz can be mitigated to below the limit level-3 of CISPR25 by changing the dominant distributed parameters.

  16. Rotor Pole Shape Optimization of Permanent Magnet Brushless DC Motors Using the Reduced Basis Technique

    Directory of Open Access Journals (Sweden)

    GHOLAMIAN, A. S.

    2009-06-01

    Full Text Available In this paper, a magnet shape optimization method for reduction of cogging torque and torque ripple in Permanent Magnet (PM brushless DC motors is presented by using the reduced basis technique coupled by finite element and design of experiments methods. The primary objective of the method is to reduce the enormous number of design variables required to define the magnet shape. The reduced basis technique is a weighted combination of several basis shapes. The aim of the method is to find the best combination using the weights for each shape as the design variables. A multi-level design process is developed to find suitable basis shapes or trial shapes at each level that can be used in the reduced basis technique. Each level is treated as a separated optimization problem until the required objective is achieved. The experimental design of Taguchi method is used to build the approximation model and to perform optimization. This method is demonstrated on the magnet shape optimization of a 6-poles/18-slots PM BLDC motor.

  17. Capacitance Estimation Algorithm based on DC-Link Voltage Harmonics Using ANN in Three-Phase Motor Drive Systems

    DEFF Research Database (Denmark)

    Soliman, Hammam Abdelaal Hammam; Davari, Pooya; Wang, Huai

    2017-01-01

    to industry. In this digest, a condition monitoring methodology that estimates the capacitance value of the dc-link capacitor in a three phase Front-End diode bridge motor drive is proposed. The proposed software methodology is based on Artificial Neural Network (ANN) algorithm. The harmonics of the dc......-link voltage are used as training data to the Artificial Neural Network. Fast Fourier Transform (FFT) of the dc-link voltage is analysed in order to study the impact of capacitance variation on the harmonics order. Laboratory experiments are conducted to validate the proposed methodology and the error analysis......In modern design of power electronic converters, reliability of dc-link capacitors is one of the critical considered aspects. The industrial field have been attracted to the monitoring of their health condition and the estimation of their ageing process status. However, the existing condition...

  18. Effect of short circuited DC link capacitor of an AC–DC–AC inverter on the performance of induction motor

    Directory of Open Access Journals (Sweden)

    Hadeed Ahmed Sher

    2016-07-01

    Full Text Available Induction motors are widely used in industrial power plants due to their robustness, reliability and high performance under variable operating conditions in the electrical power system. Modern industrial progress is dependent on these ruggedly constructed induction motors. Almost every sophisticated process of the industry is based on induction motors. Most of these motors are controlled by means of inverters that change the line frequency. The change in parameters of inverter makes it possible to control the motor according to the design requirements. The reliability of inverter based motor control is an important issue for industrial applications and therefore, it becomes very vital for design engineers to have comprehensive analysis of the inverter fed induction machine. This paper investigates one of the faults that may occur on the DC link of an inverter fed induction motor. The effect of the capacitor short circuit is presented in this paper. It also deals with the effects of short circuited capacitor on freewheeling diode. DC link capacitors are well designed and even the probability of capacitor failure is high, it is always a rare case if they puncture, however this analysis will add to the reliability of the induction machine under variable operating condition.

  19. Modeling and optimal design of DC motors with permanent magnets: development of a tool and experimental validations; Modelisation et conception optimale de moteurs a courant continu a aimants permanents: developpement d'un outil et validations experimentales

    Energy Technology Data Exchange (ETDEWEB)

    Fassenet, M.

    2001-05-01

    This work deals with the study of low power electric motors manufactured in mass production by the car industry with particularly strong technical and economical constraints. The application concerns more precisely dc commutator motors with permanent magnet driving a fan in an engine cooling system. Faced with the multiplication of electrical system per car, the manufacturers objective is to, decrease each motor bulk and as far as possible to rise their efficiency. The aim of this thesis lies in the development of a software for optimisation and design assistance. A first phase concerns the development of an analytical model which allows, from motor geometry and the characterisation of its materials, to predict magnetic and electromechanical performances for a running point or on an operating range. The principal originality of the modelling is to take into account the phenomena related to commutation and more particularly the fact that some coils are short-circuited by brushes during the armature rotation. The results obtained by the analytical model are confirmed by numerical simulations and validated by experimental results on an automated bench developed in the laboratory. The results are in very good agreement and thus allow, in a second phase, the implementation of the analytical model in an optimising procedure PASCOSMA (optimisation software developed at the laboratory of electrical engineering of Grenoble) to generate a design application. The performances expected for a running point as well as the constraints on various parameters are introduced by a convivial user interface. Automatic design of the motor is realised by respecting all the constraints and by minimising the objective function. The optimisation procedure, applied to a. given motor, allowed an increase of 3.5 points of its efficiency with a reduction of 45% of its axial bulk, in accordance with the design specifications. This work is finalized by the product of an assistance software for

  20. The DC Motor Speed Controller Using AT89S52 Microcontroller to Rotate Stepper Motor Attached into Potentiometer in Variable Regulated Power Supply

    Directory of Open Access Journals (Sweden)

    Marhaposan Situmorang

    2011-06-01

    Full Text Available The DC motor speed controller using AT89S52 microcontroller with stepper motor attached into potentiometer in variable regulated power supply had been evaluated. The voltage across DC motor is varied using program subroutine in microcontroller. The reference speed was determined using keypad and actual speed measured using rotating disc with holes in optocoupler sensor. The actual speed in rpm was determined after running time base 1 second and substracted with reference speed. The error was used to turn right stepper motor if actual speed less than reference speed and vice versa. The number of step of stepper motor rotation in one cycle execution was varied using subroutine starting from 1 step, 3 step, 5 step and using approximation of difference value between actual speed and reference speed. It was observed that the best performance of controller was achieved if number of step of turning stepper motor was not constant but depending on the difference between actual speed and reference speed.

  1. Design and Performance Test of Axial Halbach Brushless DC Motor with Power Density 1.5 Kw/Kg

    Directory of Open Access Journals (Sweden)

    Kevin Dwi Prasetio

    2017-01-01

    Full Text Available Progress of technology on electric vehicle component sector is one reason the emergence of electric vehicles at the moment. Starting from battery which has a great current density up to the automatic control systems on electric vehicles. But there are still some shortcomings of this electric vehicle components, one of which is the low value of power density of existing electric motor in the market today.On vehicles such as electric cars when Race Car Contest, energy saving problems about power density of the driving motor is very vital. This is because the total weight of the vehicle has a huge influence on the vehicle efficiency is against it. The issue is one of the reasons of the research task. In this final task is done making the design, simulation, and architecture of the Axial Halbach Brushless DC Motor. Use of system configuration on the halbach magnet to avoid the use of iron as a material cantilever rotor. By changing the material of the cantilever rotor with lighter materials such as aluminum or even carbon fibre, the value of power density electric motors can be increased. Then using the litz wire on coil stator to reduce loss-power loss due to the barriers on the coil. Coreless stator on the system and to avoid the phenomenon of cogging at the time due to low rpm style attraction magnet with iron in the core material. While the creation process begins by determining the specifications of the Axial Halbach Brushless DC motors. Then go into the design phase of the mechanical and electrical design. Who then conducted simulations to help determine other parameters such as air gap, slot turn, and magnetic orientation. The process of making a component of stator and rotor after the simulation is completed. After all the components of the rotor and stator on assembly, mounting the hall sensor is carried out to the right to position obtained by reading the signals. After the motor can spin with good motor performance, testing can be done

  2. Implementation of PID Controller in MATLAB for Real Time DC Motor Speed Control System

    Directory of Open Access Journals (Sweden)

    Manjunatha Reddy H. K.

    2011-03-01

    Full Text Available In this paper the implementation of PIDC (proportional + integral + derivative controller in MATLAB environment for real time DC motor speed control is presented. The MATLAB environment is chosen because of availability of tool boxes which allows the effective way of implementation and analysis of the control system. The performance of PID controller for different inputs is studied. To establish a communication between PC and process parameter, an indigenous Analog to digital and digital to analog (AD-DA board is designed. This board consists of 12-bit A/D converter and 12-bit D/A converter to facilitate the data acquisition and control. In the present study Advantech make PCI-1751 DIOT card is used to interface AD-DA board to PC externally. The data between the AD-DA board and the PC is communicated through the script file written in MATLAB environment. By applying different standard test commands such as step, square, staircase and triangular, the performance of PID controller is studied. The PID controller provides better system response in terms of transient as well as steady-state performances. The controller parameters are manually tuned (kp=0.232, ki=0.078 and kd=0.035 and the results of the best tuned PID controller are presented.

  3. On Stability of Open-Loop Operation without Rotor Information for Brushless DC Motors

    Directory of Open Access Journals (Sweden)

    Zhong Wu

    2014-01-01

    Full Text Available Open-loop operation mode is often used to control the Brushless DC Motors (BLDCMs without rotor position sensors when the back electromotive force (EMF is too weak due to the very low rotor velocity. The rotor position information is not necessary in this mode and the stator windings are supplied with voltages under a certain ratio of the amplitude to the frequency. However, the rotor synchronization will be destroyed once if the commutation instant is inappropriate. In order to improve the reliability of the open-loop operation mode, a dynamic equation is established to represent the synchronization error between the rotor and the stator. Thereafter, the stability of the open-loop control mode is analyzed by using Lyapunov indirect method. Theoretical analysis indicates that the open-loop control mode is asymptotically stable only when the commutation instant of the stator current lags behind the ideal one suitably. Finally, theoretical analysis is verified through the experimental results of a certain BLDCM.

  4. Maximum torque per ampere control of sensorless induction motor drives with dc offset and parameter compensation

    Energy Technology Data Exchange (ETDEWEB)

    Markadeh, Gholamreza Arab [Faculty of Engineering, Shahrekord University, Shahrekord (Iran, Islamic Republic of); Hajian, Masood, E-mail: m.hajian@ec.iut.ac.i [Department of Electrical and Computer Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Soltani, Jafar; Hosseinia, Saeed [Department of Electrical and Computer Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    2010-07-15

    Field orientation control of induction machine (IM) drives is a well-known strategy which has a fast dynamic response. In this paper, the direct rotor flux field orientation control of speed sensorless IM drive is presented. A two level space vector modulation inverter is employed to generate the command stator voltage. In proposed control scheme, a maximum torque per ampere strategy is achieved using a so-called fast flux search method. Based on this method, for a given load torque and rotor speed, the magnitude of rotor reference flux is adjusted step by step until the effective value of stator current becomes minimized finally. In addition, using the IM fifth order model in the stationary reference frame, a nonlinear rotor flux observer is developed which is also capable of motor resistances and rotor speed simultaneously estimation. Moreover, a useful method is introduced for dc offset compensation which is a major problem of ac drives especially at low speeds. The proposed control idea is experimentally implemented in real time using a CPLD board synchronized with a personal computer. Simulation and experimental results are finally presented to confirm the validity and effectiveness of the proposed method.

  5. Fast response Antiwindup PI speed controller of Brushless DC motor drive: Modeling, simulation and implementation on DSP

    Directory of Open Access Journals (Sweden)

    Mohd Tariq

    2016-05-01

    Full Text Available Most of the Brushless DC (BLDC motors drive adopts proportional, integral and derivative (PID controller and pulse width modulation (PWM scheme for speed control. Hence, BLDC motor drive has strong saturation characteristics. The saturation results in a typical windup phenomenon. The paper presents an Antiwindup drive for BLDC motor. An Antiwindup controller (AWC has been used in the paper. AWC has been modeled in MATLAB/Simulink and comparison has been done between conventional PI controller and AWC at different starting loads. Dynamic characteristics of the BLDC motor drive have been examined and results are presented and discussed in detail in this paper. Details of DSP based experimental validation of the simulated results are also presented here.

  6. Real Time Speed Control of a DC Motor Based on its Integer and Non-Integer Models Using PWM Signal

    Directory of Open Access Journals (Sweden)

    A. W. Nasir

    2017-10-01

    Full Text Available This paper exploits the advantage of non-integer order modeling of a process over integer order, in those cases where the process model is required for control purpose. The present case deals with speed control of a DC motor. Based on the real time open loop response, DC motor is being modeled as integer and non-integer order first order plus delay system. Both these models are then separately used for determining two sets of Proportional-Integral-Derivative (PID controller parameters through Ziegler Nichols (ZN closed loop tuning method. In addition to this, a model based control technique i.e. Internal Model Control (IMC is also implemented using both integer and non-integer model respectively. For carrying out the real time speed control of DC motor, LabVIEW platform has been used. After going through the results, it is observed that the controller performance considerably improves, if non-integer order model is used for controller design rather than integer order model.

  7. Electromechanical properties of a disc-type salient-pole brushless DC motor with different pole numbers

    Energy Technology Data Exchange (ETDEWEB)

    Lukaniszyn, M.; Jagiela, M.; Wrobel, R.

    2003-04-16

    A brushless, permanent magnet, three-phase disc-type salient-pole DC motor with co-axial flux in the stator is considered. Electromechanical properties of a basic eight-pole motor are compared with those for a 16-pole one of the same volume, in order to contrast the two potential candidates for variable-speed, low-cost drives. As a basis of the comparative analysis, 3D FEM magnetic field modelling and circuit analysis considering an electronic commutator are employed. Increasing the number of poles results in unfavourable raising in the switching frequency. The eight-pole motor construction has been shown in simulations to have higher efficiency and lower power losses than its 16-pole counterpart. (Author)

  8. Diagnostics of DC and Induction Motors Based on the Analysis of Acoustic Signals

    Directory of Open Access Journals (Sweden)

    Glowacz A.

    2014-10-01

    Full Text Available In this paper, a non-invasive method of early fault diagnostics of electric motors was proposed. This method uses acoustic signals generated by electric motors. Essential features were extracted from acoustic signals of motors. A plan of study of acoustic signals of electric motors was proposed. Researches were carried out for faultless induction motor, induction motor with one faulty rotor bar, induction motor with two faulty rotor bars and flawless Direct Current, and Direct Current motor with shorted rotor coils. Researches were carried out for methods of signal processing: log area ratio coefficients, Multiple signal classification, Nearest Neighbor classifier and the Bayes classifier. A pattern creation process was carried out using 40 samples of sound. In the identification process 130 five-second test samples were used. The proposed approach will also reduce the costs of maintenance and the number of faulty motors in the industry.

  9. An enhanced Z-source inverter topology-based permanent magnet brushless DC motor drive speed control

    Science.gov (United States)

    Geno Peter, P.; Rajaram, M.

    2015-08-01

    In this paper, an enhanced Z-source inverter (ZSI) is introduced for controlling the speed of permanent magnet brushless DC motor (PMBLDCM) drive. It is the extension of the conventional ZSI and the elements used in the circuit are the same as those of the conventional ZSI, except that the position of Inverter Bridge and diode would be exchanged from the classical circuit diagram. This exchanged circuit avoids the startup path of the inrush current and hence reduces the inrush current and improves the motor efficiency. Different modes of enhanced ZSI are studied with PMBLDCM. The voltage polarity of Z-source capacitors in the proposed circuit is the same as that of the input voltage polarity. Furthermore, to get the same voltage boost, the capacitor voltage stress is reduced to a significant extent. The speed control capability of the proposed brushless DC motor drive is compared with that of the conventional ZSI. The proposed ZSI is implemented in MATLAB/Simulink working platform and the output performance is evaluated. Also, the performance of voltage ratio is analysed both by simulation and mathematical models. All these analyses are known to express the innovative features of the proposed system.

  10. Numerical simulation of dynamics of brushless dc motors for aerospace and other applications. Volume 1: Model development and applications, part B

    Science.gov (United States)

    Demerdash, N. A. O.; Nehl, T. W.

    1979-01-01

    A mathematical model was developed and computerized simulations were obtained for a brushless dc motor. Experimentally obtained oscillograms of the machine phase currents are presented and the corresponding current and voltage waveforms for various modes of operation of the motor are presented and discussed.

  11. Analytical modeling of the dynamics of brushless dc motors for aerospace applications: A conceptual framework

    Science.gov (United States)

    Demerdash, N. A. O.

    1976-01-01

    The modes of operation of the brushless d.c. machine and its corresponding characteristics (current flow, torque-position, etc.) are presented. The foundations and basic principles on which the preliminary numerical model is based, are discussed.

  12. Control electrónico de velocidad de un motor DC para vehículo eléctrico

    OpenAIRE

    Montalvo Ramírez, Luis; Banda Gamboa, Hugo A.

    1983-01-01

    Se presenta el análisis y diseño del circuito troceador tipo JONES, asÍ como del cir- cuito digital, que son empleados en el sistema electrónico que controla la velocidad del motor D.C. del vehículo eléctrico construido en la Politécnica Nacional. Los resultados experimentales obtenidos con el prototipo construido son presentados y analizados, llegándose a conclusiones muy importantes para el futuro desarrollo de estos sistemas.

  13. Diseño de un observador y un controlador de velocidad de un motor DC por modos deslizantes

    Directory of Open Access Journals (Sweden)

    Jesse Mauricio Beltrán Soto

    2014-07-01

    Full Text Available En este artículo se presenta una estructura de estimación y control de estados mediante modos deslizantes para un modelo lineal. Se presenta un sistema mecánico de un Motor DC, al cual se le diseñaran un observador y un controlador deslizante de primer y segundo orden. Los resultados se comparan con un diseño de un PID. Los dos diseños se prueban ante cambios de referencia, perturbaciones y ruido.

  14. FR noise associated with time varying arc current across brush and commutator in universal motors; Universal motor ni okeru seiryu arc to denji zatsuon

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S.; Kurihara, K.; Mase, H. [Ibaraki University, Ibaraki (Japan); Takahashi, K. [Hitachi Koki Co. Ltd., Tokyo (Japan)

    1998-06-01

    EMI in the universal motors remains as a very important problem to be solved and is conventionally evaluated by the remote measurement of noise figure at the distant point from the noise source. In order to clear the mechanism of noise generation in the universal motors, we try to measure the noise pattern near the noise source by using two coils which are installed for direct detection of the time varying arc current and the noise levels in the range of 0.15 - 5 MHz. The experimental results show that the noise levels depend on the time derivatives (di/dt) of the arc current and the wide spread of noise levels are caused by randomness of arc quenching. We also discuss the propagation of noise and the comparison with the conventional evaluation of EMI, using an appropriate procedure of the obtained experimental data. 9 refs., 18 figs.

  15. Desain dan Analisis Variabel Air Gap pada Motor Axial Flux Brushless DC Berbasis 3D Finite Element Method Untuk Aplikasi Kendaraan Listrik

    Directory of Open Access Journals (Sweden)

    Achmad Abdul Ghoni

    2015-12-01

    Full Text Available Seiring berjalannya waktu dibutuhkan pengembangan teknologi pada motor penggerak pada kendaraan yang beredar dipasaran. Karena sumber energi fosil merupakan energi yang tidak dapat diperbarui, maka pengembangan kendaraan dengan listrik sebagai sumber energi adalah solusi untuk penghematan energi dimasa depan. Salah satu jenis motor yang tepat untuk digunakan sebagai penggerak kendaraan akan dibahas pada tugas akhir ini, yaitu motor axial flux brushless DC. Pada tugas akhir ini dilakukan pembuatan desain dan analisis simulasi  variabel air gap pada motor axial flux brushless DC dengan rating daya output 12 kW, tegangan DC input 400 V, frekuensi 200 Hz, dan kecepatan 2388 rpm. Varasi variabel air gap dilakukan dengan cara membuat jarak air gap pada jari-jari dalam lebih lebar dibandingkan jari-jari luar. Variasi variabel air gap yang diberikan menghasilkan perubahan nilai pada beberapa parameter kelistrikan motor. Dari simulasi yang didapatkan variasi variabel air gap terbaik pada 1,5 mm dengan kompensasi penambahan ketebalan magnet permanen sebesar 5 mm. Hasil dari variabel air gap pada motor axial flux brushless DC adalah rating daya output yang meningkat menjadi 14,5 kW dengan efisiensi 78,8 persen dan core loss sebesar 356,2 W.

  16. Perancangan dan Implementasi Pengaturan Kecepatan Motor Brushless DC Menggunakan Metode Model Predictive Control (MPC

    Directory of Open Access Journals (Sweden)

    Fachrul Arifin

    2015-12-01

    Full Text Available Saat ini, penelitian dan pengembangan mobil listrik (electric vehicle sudah menjadi pusat perhatian bagi kalangan industri dan civitas academica. Sudah banyak kendaraan listrik yang sudah diproduksi secara massal di seluruh dunia. Beberapa dari kendaraan listrik tersebut menggunakan motor BLDC sebagai penggerak utamanya. Pada Tugas Akhir kali ini, salah satu kemampuan yang akan diteliti dan dianalisa adalah respon kecepatan motor BLDC pada mobil listrik saat mobil diberi suatu beban. Ketika mendapat pembebanan, respon kecepatan dari motor BLDC akan turun sehingga performa dari motor BLDC tidak sesuai dengan setpoint yang diharapkan. Oleh karena itu, dibutuhkan suatu kontroler yang dapat mengatasi permasalahan diatas dan melakukan pengaturan kerja pada motor BLDC agar bekerja sesuai dengan kebutuhan. Kontroler ini diharapkan mampu untuk mengembalikan respon kecepatan pada motor BLDC kembali kepada setpoint ketika motor BLDC diberi pembebanan. Penulis menggunakan metode kontroler Model Predictive Control (MPC yang dapat memprediksi perilaku sistem pada masa depan yang bergantung pada informasi sistem saat ini dan model state-space dari sistem. Berdasarkan hasil implementasi, kontroler MPC dapat memberikan respon yang sesuai dengan tracking setpoint yang diberikan dengan rata-rata nilai steady-state error sebesar 9,8% untuk semua parameter pembebanan.

  17. Controlling a Four-Quadrant Brushless Three-Phase dc Motor

    Science.gov (United States)

    Nola, F. J.

    1986-01-01

    Control circuit commutates windings of brushless, three-phase, permanent-magnet motor operating from power supply. With single analog command voltage, controller makes motor accelerate, drive steadily, or brake regeneratively, in clockwise or counterclockwise direction. Controller well suited for use with energy-storage flywheels, actuators for aircraft-control surfaces, cranes, industrial robots, and other electromechanical systems requiring bidirectional control or sudden stopping and reversal.

  18. Chaos control for the output-constrained system by using adaptive dynamic surface technology and application to the brushless DC motor

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Shaohua, E-mail: hua66com@163.com [The Jiangsu Key Laboratory of Advanced Manufacturing Technology, Huaiyin Institute of Technology, Huai’an 223003 (China); School of Automation, Chongqing University, Chongqing 400044 (China); Hou, Zhiwei; Chen, Zhong [The Jiangsu Key Laboratory of Advanced Manufacturing Technology, Huaiyin Institute of Technology, Huai’an 223003 (China)

    2015-12-15

    In this paper, chaos control is proposed for the output- constrained system with uncertain control gain and time delay and is applied to the brushless DC motor. Using the dynamic surface technology, the controller overcomes the repetitive differentiation of backstepping and boundedness hypothesis of pre-determined control gain by incorporating radial basis function neural network and adaptive technology. The tangent barrier Lyapunov function is employed for time-delay chaotic system to prevent constraint violation. It is proved that the proposed control approach can guarantee asymptotically stable in the sense of uniformly ultimate boundedness without constraint violation. Finally, the effectiveness of the proposed approach is demonstrated on the brushless DC motor example.

  19. Improved transistor-controlled and commutated brushless DC motors for electric vehicle propulsion

    Science.gov (United States)

    Demerdash, N. A.; Miller, R. H.; Nehl, T. W.; Nyamusa, T. A.

    1983-01-01

    The development, design, construction, and testing processes of two electronically (transistor) controlled and commutated permanent magnet brushless dc machine systems, for propulsion of electric vehicles are detailed. One machine system was designed and constructed using samarium cobalt for permanent magnets, which supply the rotor (field) excitation. Meanwhile, the other machine system was designed and constructed with strontium ferrite permanent magnets as the source of rotor (field) excitation. These machine systems were designed for continuous rated power output of 15 hp (11.2 kw), and a peak one minute rated power output of 35 hp (26.1 kw). Both power ratings are for a rated voltage of 115 volts dc, assuming a voltage drop in the source (battery) of about 5 volts. That is, an internal source voltage of 120 volts dc. Machine-power conditioner system computer-aided simulations were used extensively in the design process. These simulations relied heavily on the magnetic field analysis in these machines using the method of finite elements, as well as methods of modeling of the machine power conditioner system dynamic interaction. These simulation processes are detailed. Testing revealed that typical machine system efficiencies at 15 hp (11.2 kw) were about 88% and 84% for the samarium cobalt and strontium ferrite based machine systems, respectively. Both systems met the peak one minute rating of 35 hp.

  20. Development of a hermetically sealed brushless DC motor for a J-T cryocooler

    Science.gov (United States)

    Joscelyn, Edwin; Hochler, Irwin; Ferri, Andrew; Rott, Heinz; Soukaris, Ted

    1996-01-01

    This development was sponsored by Ball Aerospace for the Cryogenic On-Orbit LongLife Active Refrigerator (COOLLAR) program. The cryocooler is designed to cool objects to 65 K and operate in space for at least 7 years. The system also imports minimal impact to the spacecraft in terms of vibration and heat. The basic Joule-Thompson cycle involves compressing a working fluid, nitrogen in this case, at near-constant temperature from 17.2 KPa to 6.89 MPa. The nitrogen is then expanded through a Joule-Thompson valve. The pure nitrogen gas must be kept clean; therefore, any contamination from motor organic materials must be eliminated. This requirement drove the design towards sealing of the motor within a titanium housing without sacrificing motor performance. It is estimated that an unsealed motor would have contributed 1.65 g of contaminants, due to the organic insulation and potting materials, over the 7-year life. This paper describes the motor electrical and mechanical design, as well as the sealing difficulties encountered, along with their solutions.

  1. The speed control of DC motor under the load condition using PI and PID controllers

    Science.gov (United States)

    Corapsiz, Muhammed Reşit; Kahveci, Hakan

    2017-04-01

    In this study, it was aimed to compare PI (Proportional-Integral) and PID (Proportional-Integral-Derivative) controllers for speed control of Permanent Magnet Direct Current (PMDC) motor under both load and without load. For this purpose, firstly, the mathematical model was obtained from the dynamic equations of the PMDC motor and the obtained mathematical model was transferred to the simulation environment and modeled using Matlab/SIMULINK. Following the modeling process, PI and PID controller structures were formed, respectively. Secondly, after these structures were formed, the PMDC motor was run without any controller. Then, the control of the PMDC motor with no load was provided by using PI and PID controllers. Finally, the PMDC motor were loaded under the constant load (TL = 3 N.m.) for each condition and selected time period (t = 3 s). The obtained result for each control operations was comparatively given by observing effects of loading process on systems. When the obtained results were evaluated for each condition, it was observed that PID controller have the best performance with respect to PI controller.

  2. Cogging Torque Reduction in Brushless DC Motors Using Slot-Opening Shift

    Directory of Open Access Journals (Sweden)

    SAIED, S. A.

    2009-02-01

    Full Text Available In this paper, two new methods for the stator skew are introduced. In contrary with the conventional stator skew, this paper is concentrate on the slot-opening skew. The simula-tion result by finite element shows a considerable reduction in the cogging torque of the motors, the new methods are applied to. Moreover the simulations justify that the back-EMF shape remains trapezoidal for various skew angles in contrary with that in the conventional skew, this fact makes the method highly applicable in BLDC motors.

  3. Systematic Design of a Magnetically Levitated Brushless DC Motor for a Reversible Rotary Intra-Aortic Blood Pump.

    Science.gov (United States)

    Wang, Yaxin; Logan, Thomas G; Smith, P Alex; Hsu, Po-Lin; Cohn, William E; Xu, Liping; McMahon, Richard A

    2017-10-01

    The IntraVAD is a miniature intra-aortic ventricular assist device (VAD) designed to work in series with the compromised left ventricle. A reverse-rotation control (RRc) mode has been developed to increase myocardial perfusion and reduce ventricular volume. The RRc mode includes forward rotation in systole and reverse rotation in diastole, which requires the IntraVAD to periodically reverse its rotational direction in synchrony with the cardiac cycle. This periodic reversal leads to changes in pressure force over the impeller, which makes the entire system less stable. To eliminate the mechanical wear of a contact bearing and provide active control over the axial position of the rotor, a miniature magnetically levitated bearing (i.e., the PM-Coil module) composed of two concentric permanent magnetic (PM) rings and a pair of coils-one on each side-was proposed to provide passive radial and active axial rotor stabilization. In the early design stage, the numerical finite element method (FEM) was used to optimize the geometry of the brushless DC (BLDC) motor and the maglev module, but constructing a new model each time certain design parameters were adjusted required substantial computation time. Because the design criteria for the module had to be modified to account for the magnetic force produced by the motor and for the hemodynamic changes associated with pump operation, a simplified analytic expression was derived for the expected magnetic forces. Suitable bearings could then be designed capable of overcoming these forces without repeating the complicated FEM simulation for the motor. Using this method at the initial design stage can inform the design of the miniature maglev BLDC motor for the proposed pulsatile axial-flow VAD. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  4. Speed Control of Separately Excited D.C. Motor using Self-Tuned Parameters of PID Controller

    Directory of Open Access Journals (Sweden)

    A. K. Mansoor

    2013-05-01

    Full Text Available This paper presents a simulation and hardware implementation of a closed loop control of a separately excited D.C. motor using a self-tuning PID controller. The PID controller design is based on using the Field Programmable Analog Array (FPAA technology. Parameters tuning of the PID controller is achieved by using the genetic algorithm (GA. The FPAA controller based technology gives the advantage of low power, no quantization noise, high bandwidth and high speed response. The practical results show that a self-tuning controller can outperform a hand-tuned solution and demonstrate adaptability to plant drift; also it gives very acceptable results in the reduction of overshoot, stability time and the steady-state transient response of the controlled plant.

  5. Two-stage actuation system using DC motors and piezoelectric actuators for controllable industrial and automotive brakes and clutches

    Science.gov (United States)

    Neelakantan, Vijay A.; Washington, Gregory N.; Bucknor, Norman K.

    2005-05-01

    High bandwidth actuation systems that are capable of simultaneously producing relatively large forces and displacements are required for use in automobiles and other industrial applications. Conventional hydraulic actuation mechanisms used in automotive brakes and clutches are complex, inefficient and have poor control robustness. These lead to reduced fuel economy, controllability issues and other disadvantages. This paper involves the design, development, testing and control of a two-stage hybrid actuation mechanism by combining classical actuators like DC motors and advanced smart material actuators like piezoelectric actuators. The paper also discusses the development of a robust control methodology using the Internal Model Control (IMC) principle and emphasizes the robustness property of this control methodology by comparing and studying simulation and experimental results.

  6. Sliding mode controller gain adaptation and chattering reduction techniques for DSP-based PM DC motor drives

    DEFF Research Database (Denmark)

    Dal, Mehmet; Teodorescu, Remus

    2011-01-01

    In order to achieve and maintain the prospective benefits of sliding mode control (SMC) methodology, the phenomenon known as “chattering”, the main obstacle encountered in real-time applications, has to be suppressed. In this study, two promising switching control gain adaptation and chattering...... in order to find the best solution for chattering reduction. To find a practical solution a tunable low-pass filter (LPF) was used to average the discontinuous control term. The validity of the existing conditions for the gain adaptation methods are examined and observer gain value was determined through...... simulations. To demonstrate the effectiveness of each method, several experiments were performed on a DSP-based PM DC motor drive system. Then, the newly proposed combinations of these methods were implemented. The hardware implementation results are comparatively presented and discussed....

  7. Simulation to Implementation as Good Practices for Teaching Power Electronics to Undergraduate Students: Fuzzy Sliding Mode Control for DC Motors

    Directory of Open Access Journals (Sweden)

    Paul Cepeda

    2014-01-01

    Full Text Available How can students be given experience in the confused realities of engineering processes? How can undergraduate students be convinced that processes can be analyzed and improved? Computer simulations properly designed and applied could answer these challenges revolutionizing education in Power Electronics. In recent years, computer simulation has been commonly used in education to motivate students in their learning and help teachers to improve their teaching level. The present paper focuses on developing a speed controller for DC motors starting from theoretical aspects, passing through simulations, and finally reaching a control prototype. The control theory is based on a nonlinear technique known as Sliding Mode Control (SMC involving artificial intelligence for optimization such as Fuzzy Logic (FL, Adaptive Neurofuzzy Inference Systems (ANFIS, and Genetic Algorithms (GAs.

  8. ELECTRICAL AND ELECTRONIC INDUSTRIAL CONTROL. D-C MAGNETIC MOTOR CONTROL, UNIT 7, INSTRUCTOR'S GUIDE.

    Science.gov (United States)

    SUTTON, MACK C.

    THIS GUIDE IS FOR TEACHER USE IN DIRECTING INDIVIDUAL STUDY OF DIRECT CURRENT MAGNETIC MOTOR CONTROL IN ELECTRICAL-ELECTRONIC PROGRAMS. IT WAS DEVELOPED BY AN INSTRUCTIONAL MATERIALS SPECIALIST AND ADVISERS. EACH OF THE 15 INSTRUCTOR'S SHEETS GIVES THE LESSON SUBJECT, PURPOSE, INTRODUCTORY INFORMATION, REFERENCES, AND STEP-BY-STEP SOLUTIONS OF THE…

  9. Mathematical field models of brushless DC motors with permanent magnets and their comparative analysis

    Directory of Open Access Journals (Sweden)

    A.V. Matyuschenko

    2015-03-01

    Full Text Available By means of JMAG-Designer 12 the author performed a comparative analysis of the calculation of the EMF, cogging torque and electromagnetic torque of brushless motor with permanent magnets in two-dimensional and three-dimensional formulation of the problem.

  10. Variable Reluctance Rotating Shaft Sensor for DC Brushless Vernier Reluctance Motor

    OpenAIRE

    Multon, Bernard; Geoffroy, Marc; Desesquelles, Pierre-François

    1992-01-01

    International audience; In this paper, a variable Reluctance Rotating Shaft Sensor made with a stack of magnetic sheet a Switched Reluctance Motor is studied. The magnetic coupling are taken into eaccount and an 3D FE modelization is used. Synchronous demodulation is used to obtain position signals.

  11. Position and Speed Control of Brushless DC Motors Using Sensorless Techniques and Application Trends

    Directory of Open Access Journals (Sweden)

    Jaime Gómez-Gil

    2010-07-01

    Full Text Available This paper provides a technical review of position and speed sensorless methods for controlling Brushless Direct Current (BLDC motor drives, including the background analysis using sensors, limitations and advances. The performance and reliability of BLDC motor drivers have been improved because the conventional control and sensing techniques have been improved through sensorless technology. Then, in this paper sensorless advances are reviewed and recent developments in this area are introduced with their inherent advantages and drawbacks, including the analysis of practical implementation issues and applications. The study includes a deep overview of state-of-the-art back-EMF sensing methods, which includes Terminal Voltage Sensing, Third Harmonic Voltage Integration, Terminal Current Sensing, Back-EMF Integration and PWM strategies. Also, the most relevant techniques based on estimation and models are briefly analysed, such as Sliding-mode Observer, Extended Kalman Filter, Model Reference Adaptive System, Adaptive observers (Full-order and Pseudoreduced-order and Artificial Neural Networks.

  12. Position and speed control of brushless DC motors using sensorless techniques and application trends.

    Science.gov (United States)

    Gamazo-Real, José Carlos; Vázquez-Sánchez, Ernesto; Gómez-Gil, Jaime

    2010-01-01

    This paper provides a technical review of position and speed sensorless methods for controlling Brushless Direct Current (BLDC) motor drives, including the background analysis using sensors, limitations and advances. The performance and reliability of BLDC motor drivers have been improved because the conventional control and sensing techniques have been improved through sensorless technology. Then, in this paper sensorless advances are reviewed and recent developments in this area are introduced with their inherent advantages and drawbacks, including the analysis of practical implementation issues and applications. The study includes a deep overview of state-of-the-art back-EMF sensing methods, which includes Terminal Voltage Sensing, Third Harmonic Voltage Integration, Terminal Current Sensing, Back-EMF Integration and PWM strategies. Also, the most relevant techniques based on estimation and models are briefly analysed, such as Sliding-mode Observer, Extended Kalman Filter, Model Reference Adaptive System, Adaptive observers (Full-order and Pseudoreduced-order) and Artificial Neural Networks.

  13. Bidirectional DC/DC Converter

    Science.gov (United States)

    Pedersen, F.

    2008-09-01

    The presented bidirectional DC/DC converter design concept is a further development of an already existing converter used for low battery voltage operation.For low battery voltage operation a high efficient low parts count DC/DC converter was developed, and used in a satellite for the battery charge and battery discharge function.The converter consists in a bidirectional, non regulating DC/DC converter connected to a discharge regulating Buck converter and a charge regulating Buck converter.The Bidirectional non regulating DC/DC converter performs with relatively high efficiency even at relatively high currents, which here means up to 35Amps.This performance was obtained through the use of power MOSFET's with on- resistances of only a few mille Ohms connected to a special transformer allowing paralleling several transistor stages on the low voltage side of the transformer. The design is patent protected. Synchronous rectification leads to high efficiency at the low battery voltages considered, which was in the range 2,7- 4,3 Volt DC.The converter performs with low switching losses as zero voltage zero current switching is implemented in all switching positions of the converter.Now, the drive power needed, to switch a relatively large number of low Ohm , hence high drive capacitance, power MOSFET's using conventional drive techniques would limit the overall conversion efficiency.Therefore a resonant drive consuming considerable less power than a conventional drive circuit was implemented in the converter.To the originally built and patent protected bidirectional non regulating DC/DC converter, is added the functionality of regulation.Hereby the need for additional converter stages in form of a Charge Buck regulator and a Discharge Buck regulator is eliminated.The bidirectional DC/DC converter can be used in connection with batteries, motors, etc, where the bidirectional feature, simple design and high performance may be useful.

  14. Technology and Key Strategy of IE4 Permanent Magnet Brushless DC Motor Drive for Electric Vehicle Application

    Directory of Open Access Journals (Sweden)

    Nitin Subramonium A K

    2017-03-01

    Full Text Available Environmental protection and energy conservations are the main concern of 21st century Asia Pacific developing countries. This concern has compelled to design and develop zero pollution road transportation Electric Vehicles (EVs. The EV system consist of energy storage devices such as battery, fuel cell, ultra-capacitors along with electric propulsion, body of the vehicle and energy management system with the diversified technology of electrical, electronics, mechanical, automotive and chemical engineering. The objective of electric vehicle is to produce commercial viable range, efficient performance, and comfort with safety and reliable operations at cheaper price than its counterpart the Internal Combustion Engine Vehicle (ICEV. The PMBLDC motors are the present choice of automobile industries and researchers because of its high power density, compact size, reliability, with noise free and minimum maintenance requirements. The present state of art Permanent Magnet Brushless DC (PMBLDC Motor drive for the electric vehicle application is studied / reviewed in this paper.. In addition the study also reveals the advancement of the Power Processing Unit (PPU which consists of Microelectronics and Controls (Me and C to produce the super-premium efficiency PMBLDC drive system for EV applications.

  15. Electromagnetic-Thermal Integrated Design Optimization for Hypersonic Vehicle Short-Time Duty PM Brushless DC Motor

    Directory of Open Access Journals (Sweden)

    Quanwu Li

    2016-01-01

    Full Text Available High reliability is required for the permanent magnet brushless DC motor (PM-BLDCM in an electrical pump of hypersonic vehicle. The PM-BLDCM is a short-time duty motor with high-power-density. Since thermal equilibrium is not reached for the PM-BLDCM, the temperature distribution is not uniform and there is a risk of local overheating. The winding is a main heat source and its insulation is thermally sensitive, so reducing the winding temperature rise is the key to the improvement of the reliability. In order to reduce the winding temperature rise, an electromagnetic-thermal integrated design optimization method is proposed. The method is based on electromagnetic analysis and thermal transient analysis. The requirements and constraints of electromagnetic and thermal design are considered in this method. The split ratio and the maximum flux density in stator lamination, which are highly relevant to the windings temperature rise, are optimized analytically. The analytical results are verified by finite element analysis (FEA and experiments. The maximum error between the analytical and the FEA results is 4%. The errors between the analytical and measured windings temperature rise are less than 8%. It can be proved that the method can obtain the optimal design accurately to reduce the winding temperature rise.

  16. Control de velocidad de un motor DC mediante la utilización de un sensor magnético y microcontrolador

    OpenAIRE

    ESCRIVÀ ARLANDIS, JOAN

    2013-01-01

    Este proyecto presenta el diseño de un prototipo que permitirá el control total de la transmisión de potencia en un motor DC (corriente continua), de tal manera, que se pueda ajustar la respuesta de aceleración y frenado del motor mediante cuatro parámetros, ajustándose a las necesidades del usuario, que en la aplicación final se utilizará, para regular la respuesta, a través de un sensor magnético, que actuará como acelerador y freno. La transmisión de potencia al motor, se reali...

  17. Combined Discrete Space Voltage Vector with Direct Torque Control for Bearingless Brushless DC Motor and Closed-Loop Suspended Force Control

    Directory of Open Access Journals (Sweden)

    Weiran Wang

    2013-06-01

    Full Text Available In order to improve the performance of bearingless brushless DC motor, a closed-loop suspended force controller combining the discrete space voltage vector modulation is applied and the direct torque control is presented in this paper. Firstly, we increase the number of the control vector to reduce the torque ripple. Then, the suspending equation is constructed which is spired by the direct torque control algorithm. As a result, the closed-loop suspended force controller is built. The simulated and experimental results evaluate the performance of the proposed method. The more advantage is that the proposed algorithm can achieve the fast torque response, reduce the torque ripple, and follow ideal stator flux track. Furthermore, the motor which implants the closed-loop suspended force controller cannot onlyobtain the dynamic response rapidly and displacement control accurately, but also has the characteristics of bearingless brushless DC motor (such as simple structure, high energy efficiency, small volume and low failure rate.

  18. Aspects Concerning the Torque Ripple Control of the Brushless DC Motor

    Directory of Open Access Journals (Sweden)

    BALUTA, G.

    2013-05-01

    Full Text Available This paper deals with two advanced numerical structures to control the electromagnetic torque ripple of Brushless Direct Current Motors (BLDCM, indirectly achieved by phase currents control and directly by the Direct Torque Control (DTC technique. In DTC there was implemented an observer to increase the rudimentary transducer resolution, containing three Hall Effect sensors. The experimental results describe the evolution of torque in both situations of control and are obtained by applying a control strategy for an electric drive system with BLDCM with trapezoidal Back-EMF in Two-Phase Mode.

  19. Let the Brushing Games Begin

    Science.gov (United States)

    ... on bedtime brushing, technically speaking, your goal of brushing teeth is to clean food off of them, and ... adults we know make a regular habit of brushing their teeth throughout the day. Start having your child brush ...

  20. Gate Driver Circuit of Power Electronic Switches with Reduced Number of Isolated DC/DC Converter for a Switched Reluctance Motor

    Directory of Open Access Journals (Sweden)

    Ali Asghar Memon

    2013-04-01

    Full Text Available This paper presents a gate driver circuit for the switching devices used in the asymmetrical converter for a switched reluctance machine with reduced number of isolated dc/dc converters. Isolation required in the gate driver circuit of switching devices is indispensable. For the purpose of isolation different arrangements may be used such as pulse transformers. The dc/dc converter for isolation and powering the gate drive circuits is suitable, cheaper in cost and simple to implement. It is also significant that required number of isolation converters is much less than the switches used in converter. In addition, a simple logic circuit has been presented for producing the gate signals at correct phase sequence which is compared with the gated signals directly obtained from the encoder of an existing machine.

  1. DC Home Appliances for DC Distribution System

    Directory of Open Access Journals (Sweden)

    MUHAMMAD KAMRAN

    2017-10-01

    Full Text Available This paper strengthens the idea of DC distribution system for DC microgrid consisting of a building of 50 apartments. Since the war of currents AC system has been dominant because of the paucity of research in the protection of the DC system. Now with the advance research in power electronics material and components, generation of electricity is inherently DC as by solar PV, fuel cell and thermoelectric generator that eliminates the rectification process. Transformers are replaced by the power electronics buck-boost converters. DC circuit breakers have solved the protection problems for both DC transmission and distribution system. In this paper 308V DC microgrid is proposed and home appliances (DC internal are modified to operate on 48V DC from DC distribution line. Instead of using universal and induction motors in rotary appliances, BLDC (Brushless DC motors are proposed that are highly efficient with minimum electro-mechanical and no commutation losses. Proposed DC system reduces the power conversion stages, hence diminishes the associated power losses and standby losses that boost the overall system efficiency. So in view of all this a conventional AC system can be replaced by a DC system that has many advantages by cost as well as by performance

  2. A simple overlap angle control strategy for reducing commutation torque ripple in a brushless DC motor drive

    Directory of Open Access Journals (Sweden)

    Chetan K. Lad

    2017-08-01

    Full Text Available A commutation torque ripple is generated in a brushless DC motor due to a finite time taken for current transfer between outgoing phase and incoming phase due to the phase inductance. The effect of commutation ripple will be more severe for low voltage high current BLDC drives used for automotive applications. Direct Torque Control (DTC techniques are used to reduce the torque ripple. Two phase conduction with six voltage space vectors and three phase conduction with twelve voltage space vectors with DTC are used to reduce the torque ripple. Twelve Step DTC (TSDTC is capable of reducing torque ripple considerably but at the cost of increased inverter and winding losses. In Six Step DTC (SSDTC the torque ripple is higher than that of TSDTC but with reduced winding and inverter losses. In this paper an attempt has been made to strike a balance between torque ripple and losses. A novel Direct Torque Control with twelve voltage space vector with overlap angle control has been proposed. The proposed method is validated through simulation and experimental results.

  3. Design, implementation, and application of 150-degree commutation VSI to improve speed range of sensored BLDC motor

    Science.gov (United States)

    Ozgenel, Mehmet Cihat

    2017-09-01

    Permanent magnet brushless dc (BLDC) motors are very convenient for many applications such as industrial, medical, robotic, aerospace, small electric vehicles, and home applications because of their inherent satisfying dynamic characteristics. There are numerous studies about these motors and their control schemes such as sensorless control and different speed and torque control schemes. All electric motors need commutation in order to produce speed and torque. Commutation in brushed DC motors is performed by means of a brush and collector. In BLDC motors, commutation is provided electronically in contrast to the brushed dc motors. In BLDC motors, motor phase windings are energized according to the information of the rotor position by inverter transistors. Rotor position information is used for commutation. Therefore, rotor position information is required to produce speed and torque for BLDC motors. The easiest and cheapest way to obtain rotor position information is to use Hall-effect or optical sensors. BLDC motor manufacturers generally produce BLDC motors equipped with three Hall-effect position sensors. Having three position sensors on BLDC motors provides six-step commutation which ensures two phase windings are energized in each moment. The third phase is empty. In this study, all phase windings are energized in the same time. This commutation method is twelve-step or 150 degrees commutation. So that more speed can be achieved from the same BLDC motor by comparison with six-step commutation. In this paper, both six-step and twelve-step commutation methods applied to the same BLDC motor and obtained experimental results from this study were presented, examined, and discussed.

  4. AUTOMATED MEASURING COMPLEX FOR ACCEPTANCE TESTING OF DC AND UNDULATED-CURRENT TRACTION MOTORS

    Directory of Open Access Journals (Sweden)

    A. Yu. Drubetskyi

    2016-12-01

    Full Text Available Purpose. In the paper it is necessary: 1 to familiarize the reader with the modern classification of measurement and diagnostics, familiarize with problems of automating the measurement of basic parameters during program execution of qualification tests of traction motors; 2 to make recommendations to improve the measurement ac-curacy, reduce labor intensity of work for carrying out measurements, and reduce the requirements for the qualification of the staff; 3 to provide practical implementation of measurement system, built on the basis of the practical recommendations contained in the article. Methodology. The work presents the classification of measurement and diagnostic tools. The author considered a list of equipment that can be used in measurement systems, as well as third-party options for measuring complex and measuring complex using stand management system. Their functional schemes were proposed. The author compared the advantages and disadvantages of these schemes to make recommendations on areas of their optimal use. Findings. Having analyzed the functional scheme of measuring systems, it was found that the use of the control system microcontroller as a measuring complex is expedient if the measurements have largely a test process control function. The use of a third-party measuring complex is more appropriate in cases when it is required: to eliminate dependence on the stand management system, to provide high mobility and reduce the requirements for the qualification of the staff. Originality. The work presents a brief over-view of the measurement means. The author developed the functional schemes of measuring systems using stand management system and third-party measuring complex, proposed the criteria for evaluating their optimal use. Practical value. Based on the proposed functional diagram, the measuring system on National Instruments hard-ware and software basis was set up. The sensors by LEM Company were used as primary

  5. EMI performance comparison of two-level and three-level inverters in small dc-link capacitors based motor drives

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.

    2012-01-01

    The size of passive components in an adjustable speed drive can be reduced by using small dc-link capacitors. The EMI filter in the drive also consists of passive components. The size of the filter can be reduced by using a three-level inverter, which can have low output voltage distortion. However......, the three-level inverter based on small dc-link capacitors requires a PWM strategy to maintain neutral-point voltage balance. In this paper, the common mode voltage, which is the determining factor for the EMI filter size, is analyzed for a virtual-vector-based PWM strategy. The common mode voltage....... Results show that the conducted emission from the three-level inverter is lower than that of the two-level inverter. Thus, a three-level inverter requires a smaller EMI filter in motor drives with small dc-link capacitors....

  6. Desarrollo de un controlador para motores DC brushless basado en CompactRIO y LabVIEW de National Instruments para el estudio de nuevos algoritmos de control

    OpenAIRE

    García Haro, Juan Miguel

    2011-01-01

    Este proyecto que el CAR inició hace pocos años tiene como objetivo principal el estudio y desarrollo de nuevas tecnologías en el campo de actuación y control automático, que servirá de base para otras futuras investigaciones dentro del centro. La tecnología a la que se hace mención se refiere al control de actuadores basados en motores DC brushless (BLDC Motors) empleando el sistema de hardware embebido CompactRIO y programación LabVIEW de National Instruments. Tradicionalmente se emplea en ...

  7. Cross-Correlation of Motor Activity Signals from dc-Magnetoencephalography, Near-Infrared Spectroscopy, and Electromyography

    Directory of Open Access Journals (Sweden)

    Tilmann H. Sander

    2010-01-01

    Full Text Available Neuronal and vascular responses due to finger movements were synchronously measured using dc-magnetoencephalography (dcMEG and time-resolved near-infrared spectroscopy (trNIRS. The finger movements were monitored with electromyography (EMG. Cortical responses related to the finger movement sequence were extracted by independent component analysis from both the dcMEG and the trNIRS data. The temporal relations between EMG rate, dcMEG, and trNIRS responses were assessed pairwise using the cross-correlation function (CCF, which does not require epoch averaging. A positive lag on a scale of seconds was found for the maximum of the CCF between dcMEG and trNIRS. A zero lag is observed for the CCF between dcMEG and EMG. Additionally this CCF exhibits oscillations at the frequency of individual finger movements. These findings show that the dcMEG with a bandwidth up to 8 Hz records both slow and faster neuronal responses, whereas the vascular response is confirmed to change on a scale of seconds.

  8. Brushless three-phase synchronous motor using an armature winding both as load and DC exciting windings. Denkishi makisen ga chokuryu reiji makisen wo kaneta brushless sanso doki dendoki

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, F.; Fukami, T. (Kanazawa Institute of Technology, Ishikawa (Japan))

    1992-08-15

    In this paper, configuration of a brushless three-phase synchronous motor with no exciter is proposed. The applied technique is effective to simplify the conventional brushless synchronous motor configuration. A stator of the motor is equipped with a double-star connected armature winding with two neutral points for DC exciting. A cylindrical stator is equipped with a two-phase field winding, which is connected with shaft-mounted rectifiers. During the operation of the motor at synchronous speed, DC voltage is applied to the two neutral points of the armature winding for excitation of the rotor. At that time, the armature winding acts as a stator DC exciting winding and a load winding. This paper describes the principle and the characteristic analysis of the new motor as well as the experimental results of the 2kW test-motor. The experimental results almost agree with the analytical results, so that the favorable performance characteristics of the proposed motor were confirmed. For instance, the power factor of this motor can be controlled in a wide range by adjusting the stator DC exciting current. 9 refs., 8 figs., 1 tab.

  9. Unbalanced Magnetic Pull Effect on Stiffness Models of Active Magnetic Bearing due to Rotor Eccentricity in Brushless DC Motor Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Bangcheng Han

    2013-01-01

    Full Text Available We firstly report on an investigation into the unbalanced magnetic pull (UMP effect on the static stiffness models of radial active magnetic bearing (RAMB in brushless DC motor (BDCM in no-loaded and loaded conditions using the finite element method (FEM. The influences of the UMP on the force-control current, force-position, current stiffness, and position stiffness of RAMB are clarified in BDCM with 100 kW rated power. We found the position stiffness to be more susceptible to UMP. The primary source of UMP is the permanent magnets of BDCM. In addition, the performance of RAMB is affected by the UMP ripples during motor commutation and also periodically affected by the angular position of rotor. The characteristic curves of RAMB force versus control current (or rotor position and angular position of rotor affected by the UMP are given. The method is useful in design and optimization of RAMB in magnetically suspended BDCMs.

  10. High Temperature All Silicon-Carbide (SiC) DC Motor Drives for Venus Exploration Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project seeks to prove the feasibility of creating high-temperature silicon-carbide (SiC) based motor drives for...

  11. Comprehensive Performance Evaluation of a High Speed Brushless DC Motor Using an Improved Phase Variable Model(Special Issue to the Asia-Pacific Symposium on Applied Electromagnetics and Mechanics (APSAEM06))

    OpenAIRE

    Jiaxin, Chen; Youguang, Guo; Jianguo, Zhu; College of Electromechanical Engineering, Donghua University : Faculty of Engineering, University of Technology; Faculty of Engineering, University of Technology; Faculty of Engineering, University of Technology

    2007-01-01

    This paper presents the performance evaluation of a high-speed surface mounted PM brushless DC motor by using an improved phase variable model. Magnetic field finite element analyses are conducted to accurately calculate the key motor parameters such as air gap flux, back electromotive force and inductance, and their dependence on rotor position and magnetic saturation. Based on the numerical magnetic field solutions, a modified incremental energy method is applied to effectively calculate th...

  12. Polymer brushes: routes toward mechanosensitive surfaces.

    Science.gov (United States)

    Bünsow, Johanna; Kelby, Tim S; Huck, Wilhelm T S

    2010-03-16

    Soft nanotechnology involves both understanding the behavior of soft matter and using these components to build useful nanoscale structures and devices. However, molecular scale properties such as Brownian motion, diffusion, surface forces, and conformational flexibility dominate the chemistry and physics in soft nanotechnology, and therefore the design rules for generating functional structures from soft, self-assembled materials are still developing. Biological motors illustrate how wet nanoscale machines differ from their macroscopic counterparts. These molecular machines convert chemical energy into mechanical motion through an isothermal process: chemical reactions generate chemical potential and diffusion of ions, leading to conformational changes in proteins and the production of mechanical force. Because the actuation steps form a thermodynamic cycle that is reversible, the application of mechanical forces can also generate a chemical potential. This reverse process of mechanotransduction is the underlying sensing and signaling mechanism for a wide range of physiological phenomena such as hearing, touch, and growth of bone. Many of the biological systems that respond to mechanical stimuli do this via complex stress-activated ion channels or remodeling of the actin cytoskeleton. These biological actuation and mechanosensing processes are rather different from nano- and microelectromechanical systems (NEMS and MEMS) produced via semiconductor fabrication technologies. In our group, we are working to emulate biological mechanotransduction by systematically developing building blocks based on polymer brushes. In this soft nanotechnology approach to mechanotransduction, the chemical building blocks are polymer chains whose conformational changes and actuation can be investigated at a very basic level in polymer brushes, particularly polyelectrolyte brushes. Because these polymer brushes are easily accessible synthetically with control over parameters such as

  13. Closed loop performance of a brushless dc motor powered electromechanical actuator for flight control applications. [computerized simulation for Shuttle Orbiter applications

    Science.gov (United States)

    Demerdash, N. A.; Nehl, T. W.

    1980-01-01

    A comprehensive digital model for the analysis and possible optimization of the closed loop dynamic (instantaneous) performance of a power conditioner fed, brushless dc motor powered, electromechanical actuator system (EMA) is presented. This model was developed for the simulation of the dynamic performance of an actual prototype EMA built for NASA-JSC as a possible alternative to hydraulic actuators for consideration in Space Shuttle Orbiter applications. Excellent correlation was achieved between numerical model simulation and experimental test results obtained from the actual hardware. These results include: various current and voltage waveforms in the machine-power conditioner (MPC) unit, flap position as well as other control loop variables in response to step commands of change of flap position. These results with consequent conclusions are detailed in the paper.

  14. Endobiliary brush biopsy

    DEFF Research Database (Denmark)

    Adamsen, Sven; Olsen, Marianne; Jendresen, Marianne Bille

    2006-01-01

    OBJECTIVE: Obtaining cytological specimens by wire-guided endobiliary brushing at the time of endoscopic retrograde cholangiopancreatography (ERCP) is a convenient way to reach a diagnosis. Sensitivity for malignant disease is generally around 50% and specificity around 100%. The present study wa...

  15. Brushing Your Child's Teeth

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000769.htm Brushing Your Child's Teeth To use the sharing features on this page, ... M. Editorial team. Related MedlinePlus Health Topics ... among the first to achieve this important distinction for online health information and services. Learn ...

  16. Real Time Implementation of PID and Fuzzy PD Controllers for DC-Servo Motor Based on Lab View Environment

    OpenAIRE

    Safaa M. Z. Al-Ubaidi; Maher M. F. Algreer

    2012-01-01

    This paper presents an implementation of conventional PID (CPID) controller using Ziegler-Nichols rules and fuzzy PD (FPD) controller for position servo motor control based on Lab View (Laboratory Virtual Instrument Engineering Workbench Environment) through Data Acquisition (DAQ) Device PCI- 6521 of National Instrument's and Data Acquisition Accessory Board Model (CB-68LP).CPID controller is perhaps the most well-known and most widely used in industrial applications. However, it has been kno...

  17. Real Time Implementation of PID and Fuzzy PD Controllers for DC-Servo Motor Based on Lab View Environment

    Directory of Open Access Journals (Sweden)

    Safaa M. Z. Al-Ubaidi

    2012-06-01

    Full Text Available This paper presents an implementation of conventional PID (CPID controller using Ziegler-Nichols rules and fuzzy PD (FPD controller for position servo motor control based on Lab View (Laboratory Virtual Instrument Engineering Workbench Environment through Data Acquisition (DAQ Device PCI- 6521 of National Instrument's and Data Acquisition Accessory Board Model (CB-68LP.CPID controller is perhaps the most well-known and most widely used in industrial applications. However, it has been known that CPID controller generally don’t work well for non-linear systems, higher order and time-delayed linear system and particularly complex and vague system. To overcome these difficulties, this paper proposes to use the FPD controller for a servo motor system instead of CPID. The parameters of servo motor used are completely unknown. The FPD structure has two-input single-output and fairly similar characteristic to its conventional counterpart and provides good performance. Simple rules base are used for FPD (nine rules only. Performance evaluation was carried out via a comparison study for the proposed control scheme and other existing control scheme, such as CPID controller. The critical point for this experiment on position system is a steady state error and settling time.  The performance showing that the FPD has less settling time and zero steady state error over its CPID. The algorithms of FPD and CPID controllers are implemented using PID, Fuzzy Logic and simulation toolkits of the Lab View environment.

  18. Improved ITOS attitude control system with Hall generator brushless motor and earth-splitting technique

    Science.gov (United States)

    Peacock, W. M.

    1971-01-01

    The ITOS with an improved attitude control system is described. A Hall generator brushless dc torque motor will replace the brush dc torque motor on ITOS-I and ITOS-A (NOAA-1). The four attitude horizon sensors will be replaced with two CO2 sensors for better horizon definition. An earth horizon splitting technique will be used to keep the earth facing side of the satellite toward earth even if the desired circular orbit is not achieved. The external appearance of the pitch control subsystem differs from TIROS-M (ITOS-1) and ITOS-A (NOAA-1) in that two instead of one pitch control electronics (PCE) boxes are used. Two instead of four horizon sensors will be used and one instead of two mirrors will be used for sensor scanning. The brushless motor will eliminate the requirement for brushes, strain gages and the telemetry for the brush wear. A single rotating flywheel, supported by a single bearing provides the gyroscopic stability and the required momentum interchange to keep one side of the satellite facing the earth. Magnetic torquing against the earth's magnetic field eliminates the requirement for expendable propellants which would limit satellite life in orbit.

  19. DNA decontamination of fingerprint brushes.

    Science.gov (United States)

    Szkuta, Bianca; Oorschot, Roland A H van; Ballantyne, Kaye N

    2017-08-01

    Genetic profiling of DNA collected from fingerprints that have been exposed to various enhancement techniques is routine in many forensic laboratories. As a result of direct contact with fingermark residues during treatment, there is concern around the DNA contamination risk of dusting fingermarks with fingerprint brushes. Previous studies have demonstrated the potential for cross-contamination between evidentiary items through various mechanisms, highlighting the risk of using the same fingerprint brush to powder multiple surfaces within and between crime-scenes. Experiments were performed to assess the contamination risk of reused fingerprint brushes through the transfer of dried saliva and skin deposits from and to glass surfaces with new unused squirrel hair and fiberglass brushes. Additional new unused brushes and brushes previously used in casework were also tested for their ability to contaminate samples. In addition, the ability to eradicate DNA from used squirrel hair and fiberglass fingerprint brushes was assessed using a 1% sodium hypochlorite solution and a 5% solution of a commercially available alternative, Virkon. DNA profiling results from surfaces contacted by treated and untreated brushes were compared to determine the effectiveness of the devised cleaning protocol. Brush durability was also assessed over multiple wash/rinse/dry cycles with both agents. Varying amounts of DNA-containing material were collected and transferred by squirrel hair and fiberglass brushes, with detectability on the secondary surface dependent on the biological nature of the material being transferred. The impact of DNA contamination from dirty fingerprint brushes was most apparent in simulations involving the transfer of dried saliva and brushes previously used in casework, while minimal transfer of touch DNA was observed. Alarmingly, large quantities of DNA were found to reside on new unused squirrel hair brushes, while no DNA was detected on new unused fiberglass

  20. Bottle-Brush Brushes: Cylindrical Molecular Brushes of Poly(2-oxazoline) on Glassy Carbon

    KAUST Repository

    Zhang, Ning

    2009-07-28

    We report on the synthesis of brushes of bottle-brushes of poly(2-oxazoline)s on polished glassy carbon (GC) substrates. First, homogeneous and stable poly(2-isopropenyl-2-oxazoline) (PIPOx) brush layers with thicknesses up to 160 nm were created directly onto GC by the self-initiated photografting and photopolymerization (SIPGP) of 2-isopropenyl-2-oxazoline (IPOx). Kinetic studies reveal a linear increase in thickness with the polymerization time. In a second reaction, the pendant 2-oxazoline ring of the PIPOx brushes were used for the living cationic ring-opening polymerization (LCROP) with different substituted 2-oxazoline monomers to form the side chains. Also for the second surface-initiatedLCROPfrom the surface-bound macroinitiator brushes, the thickness increase with the polymerization time was found to be linear and reproducible. Characterization of the resulting bottle-brush brushes by FTIR spectroscopy,contact angle, and AFM indicates a high side chain grafting density and quantitative reactions. Finally, we have demonstrated the possibility of functionalizing the bottle-brush brushes side chain end groups with sterically demanding molecules. © 2009 American Chemical Society.

  1. Motor Music

    OpenAIRE

    Richards, John

    2014-01-01

    Motor Music II (2014) for small group and motors What happens when an AC or DC motor is plugged raw into a mixing desk or connected directly to a speaker? Motor Music II explores ‘low level’ instrument design and a reductionist approach. The piece also sets up a proposition concerning electronic music: ‘How can it be done simpler?’ The motor as ‘instrument’ encourages an objection-orientated approach to sound and music making: the motor itself has inherent musical qualities and po...

  2. Electrostatically anchored branched brush layers.

    Science.gov (United States)

    Liu, Xiaoyan; Dedinaite, Andra; Rutland, Mark; Thormann, Esben; Visnevskij, Ceslav; Makuska, Ricardas; Claesson, Per M

    2012-11-06

    A novel type of block copolymer has been synthesized. It consists of a linear cationic block and an uncharged bottle-brush block. The nonionic bottle-brush block contains 45 units long poly(ethylene oxide) side chains. This polymer was synthesized with the intention of creating branched brush layers firmly physisorbed to negatively charged surfaces via the cationic block, mimicking the architecture (but not the chemistry) of bottle-brush molecules suggested to be present on the cartilage surface, and contributing to the efficient lubrication of synovial joints. The adsorption properties of the diblock copolymer as well as of the two blocks separately were studied on silica surfaces using quartz crystal microbalance with dissipation monitoring (QCM-D) and optical reflectometry. The adsorption kinetics data highlight that the diblock copolymers initially adsorb preferentially parallel to the surface with both the cationic block and the uncharged bottle-brush block in contact with the surface. However, as the adsorption proceeds, a structural change occurs within the layer, and the PEO bottle-brush block extends toward solution, forming a surface-anchored branched brush layer. As the adsorption plateau is reached, the diblock copolymer layer is 46-48 nm thick, and the water content in the layer is above 90 wt %. The combination of strong electrostatic anchoring and highly hydrated branched brush structures provide strong steric repulsion, low friction forces, and high load bearing capacity. The strong electrostatic anchoring also provides high stability of preadsorbed layers under different ionic strength conditions.

  3. Drilling Deeper into tooth brushing skills: Is proactive interference an under-recognized factor in oral hygiene behavior change?

    Science.gov (United States)

    Thavarajah, Rooban; Kumar, Madan; Mohandoss, Anusa Arunachalam; Vernon, Lance T

    2015-09-01

    Proper tooth brushing is a seemingly simple motor activity that can promote oral health. Applying health theories, such as the Information-Motivation-Behavioral Skills (IMB) model, Motivational Interviewing (MI) and Integrated Health Coaching (IHC), may help optimize tooth brushing technique in those with suboptimal skills. Some motor activities, including tooth brushing, may over time become rote and unconscious actions, such that an existing habit can inhibit new learning, i.e., exert proactive interference on learning the new skill. Proactive interference may impede the acquisition of new tooth brushing skills; thus, in this report, we: (1) Review how the habit of tooth brushing is formed; (2) Postulate how proactive interference could impede the establishment of proper tooth brushing retraining; (3) Discuss the merits of this hypothesis; and (4) Provide guidance for future work in this topic within the context of an approach to behavior change that integrates IMB, MI and IHC methodology.

  4. A novel miniaturized zinc oxide/hydroxylated multiwalled carbon nanotubes as a stir-brush microextractor device for carbamate pesticides analysis

    Energy Technology Data Exchange (ETDEWEB)

    Makkliang, Fonthip; Kanatharana, Proespichaya [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thavarungkul, Panote [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thammakhet, Chongdee, E-mail: chongdee.t@psu.ac.th [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand)

    2016-04-21

    A novel miniaturized “stir-brush microextractor” was prepared using a zinc oxide/hydroxylated multiwalled carbon nanotubes (ZnO/MWCNTs–OH) coated stainless steel brush connected to a small dc motor. The synthesized zinc oxide on each strand of stainless steel had a flower-like nanostructure when observed by a scanning electron microscope (SEM). This structure produced a large surface area before it was coated with the hydroxylated multiwalled carbon nanotubes sorbent. Under optimal conditions, the developed device provided a good linearity for the extraction of carbofuran and carbaryl, in the range of 25–500 ng mL{sup −1} and 50–500 ng mL{sup −1}, respectively, with low limits of detection of 17.5 ± 2.0 ng mL{sup −1} and 13.0 ± 1.8 ng mL{sup −1}. It also provided a good stir-brush-to-stir-brush reproducibility (% relative standard deviation < 5.6%, n = 6). The device was applied for the extraction and preconcentration of carbamate pesticides in fruit and vegetable samples prior to analysis with a gas chromatograph coupled with a flame ionization detector (GC–FID). Carbofuran was found at 9.24 ± 0.93 ng g{sup −1} and carbaryl was detected at 7.05 ± 0.61 ng g{sup −1} with good recoveries in the range of 73.7 ± 10.0% to 108.4 ± 2.6% for carbofuran and 75.7 ± 10.0% to 111.7 ± 5.7% for carbaryl. - Highlights: • A brush as the sampling tool was first introduced. • A novel miniaturized and portable stir brush microextractor was developed for carbamate pesticides extraction. • Large surface area of ZnO flower-like nanostructure coated with MWCNTs–OH on each brush fiber was observed.

  5. Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller

    Directory of Open Access Journals (Sweden)

    Sreenivasappa Veeranna Bhupasandra

    2010-01-01

    Full Text Available In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the PWM controller.

  6. Polymer brushes: promises and challenges.

    Science.gov (United States)

    Yameen, Basit; Farrukh, Aleeza

    2013-08-01

    Surface-tethered polymers, or "polymer brushes", are emerging as key elements in the context of regulating the surface characteristics of materials. Their properties, such as biocompatibility, antifouling, colloidal stability, wettability, and corrosion resistance, play a vital role in ascertaining their potential applications. The availability of straightforward procedures for polymer brush synthesis, which are applicable to a wide range of monomers and are adaptable to a range of substrates, is a clear advantage over other surface-modification strategies. Herein, the important advancements that are pertinent to the fabrication of polymer brushes are outlined. Furthermore, an exhaustive up-to-date overview of the developments in different application domains, including smart drug-delivery systems, biosensing, antifouling, stimuli-responsive surfaces, and ion-conducting membranes, that benefit from the developments in the field of polymer brushes, is presented. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Quad-copter UAV BLDC Motor Control: Linear v/s non-linear control maps

    Directory of Open Access Journals (Sweden)

    Deep Parikh

    2015-08-01

    Full Text Available This paper presents some investigations and comparison of using linear versus non-linear static motor-control maps for the speed control of a BLDC (Brush Less Direct Current motors used in quad-copter UAV (Unmanned Aerial Vehicles. The motor-control map considered here is the inverse of the static map relating motor-speed output to motor-voltage input for a typical out-runner type Brushless DC Motors (BLDCM.  Traditionally, quad-copter BLDC motor speed control uses simple linear motor-control map defined by the motor-constant specification. However, practical BLDC motors show non-linear characteristic, particularly when operated across wide operating speed-range as is commonly required in quad-copter UAV flight operations. In this paper, our investigations to compare performance of linear versus non-linear motor-control maps are presented. The investigations cover simulation-based and experimental study of BLDC motor speed control systems for  quad-copter vehicle available. First the non-linear map relating rotor RPM to motor voltage for quad-copter BLDC motor is obtained experimentally using an optical speed encoder. The performance of the linear versus non-linear motor-control-maps for the speed control are studied. The investigations also cover study of time-responses for various standard test input-signals e.g. step, ramp and pulse inputs, applied as the reference speed-commands. Also, simple 2-degree of freedom test-bed is developed in our laboratory to help test the open-loop and closed-loop experimental investigations. The non-linear motor-control map is found to perform better in BLDC motor speed tracking control performance and thereby helping achieve better quad-copter roll-angle attitude control.

  8. In-orbit performance of the ITOS improved attitude control system with Hall generator brushless motor and earth-splitting technique

    Science.gov (United States)

    Peacock, W. M.

    1973-01-01

    The National Aeronautics and Space Administration (NASA), launched ITOS-D with an improved attitude control system. A Hall generator brushless dc torque motor replaced the brush dc torque motor on Tiros-M and ITOS-A. Two CO2 attitude horizon sensors and one mirror replaced the four wideband horizon sensors and two mirrors on ITOS-1 and NOAA-1. Redundant pitch-control electronic boxes containing additional electronic circuitry for earth-splitting and brushless motor electronics were used. A method of generating a spacecraft earth-facing side reference for comparison to the time occurrence of the earth-splitting pulse was used to automatically correct pitch-attitude error. A single rotating flywheel, supported by a single bearing, provided gyroscopic stability and the required momentum interchange to keep one side of the satellite facing the earth. Magnetic torquing against the earth's magnetic field eliminated the requirement for expendable propellants which would limit satellite life in orbit.

  9. Brushless direct-current motor with stationary armature and field

    Science.gov (United States)

    Studer, P. A.

    1970-01-01

    Electronically commutated dc motor has an active fixed field winding, and active fixed armature winding, and passive rotor. By use of brushless dc motor switching technique, motor provides continuous controllable and reversible torque without use of sliding contacts.

  10. Area Selective Polymer Brush Deposition.

    Science.gov (United States)

    Cummins, Cian; Shaw, Matthew T; Morris, Michael A

    2017-08-01

    Polymer brush films with chemical functionality to attach to site specific substrate areas are introduced for area selective deposition (ASD) application. It is demonstrated that polymer brushes with chemically defined end sites can be selectively bound to copper-specific regions of patterned copper/silica (Cu/SiO2 ) substrates. The process described overcomes various limitations of currently used technology including cost, complexity, and throughput, with potential implications for future electronic devices and nanomanufacturing. A comparative study of amine-terminated polystyrene and amine-terminated poly-2-vinyl pyridine polymer brushes (i.e., PS-NH2 and P2VP-NH2 ) with similar molecular weights display contrasting behavior on patterned Cu/SiO2 line features. Further, a thiol terminated poly-2-vinyl pyridine polymer brush (i.e., P2VP-SH) is investigated as a direct spin-on process to fabricate a metal oxide layer atop Cu areas only. The results presented here detail a novel methodology and open a new exciting process for ASD practices that can facilitate the precise deposition of dense metal, semiconductor, or dielectric films. We also discuss the applicability of polymer brushes to ASD uses going forward. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. DC + RSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne

    1996-01-01

    This document gives some initial ideas of how the Duration Calculus (DC) can be integrated with the RAISE Specification Language (RSL).......This document gives some initial ideas of how the Duration Calculus (DC) can be integrated with the RAISE Specification Language (RSL)....

  12. Determination of efficiencies, loss mechanisms, and performance degradation factors in chopper controlled dc vehical motors. Section 2: The time dependent finite element modeling of the electromagnetic field in electrical machines: Methods and applications. Ph.D. Thesis

    Science.gov (United States)

    Hamilton, H. B.; Strangas, E.

    1980-01-01

    The time dependent solution of the magnetic field is introduced as a method for accounting for the variation, in time, of the machine parameters in predicting and analyzing the performance of the electrical machines. The method of time dependent finite element was used in combination with an also time dependent construction of a grid for the air gap region. The Maxwell stress tensor was used to calculate the airgap torque from the magnetic vector potential distribution. Incremental inductances were defined and calculated as functions of time, depending on eddy currents and saturation. The currents in all the machine circuits were calculated in the time domain based on these inductances, which were continuously updated. The method was applied to a chopper controlled DC series motor used for electric vehicle drive, and to a salient pole sychronous motor with damper bars. Simulation results were compared to experimentally obtained ones.

  13. Bidirectional DC-DC converter fed drive for electric vehicle system

    African Journals Online (AJOL)

    ATHARVA

    During acceleration and normal modes the power flow is from battery to motor where as during braking or regenerative mode the kinetic energy of the motor is converted into electrical energy and fed back to battery. The DC-DC converter is required to perform mainly two functions: first to match the battery voltage to the ...

  14. 21 CFR 884.1100 - Endometrial brush.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Endometrial brush. 884.1100 Section 884.1100 Food... Endometrial brush. (a) Identification. An endometrial brush is a device designed to remove samples of the... endometrial cytology (cells). (b) Classification. Class II. The special controls for this device are: (1) FDA...

  15. 75 FR 13489 - Natural Bristle Paint Brushes and Brush Heads from the People's Republic of China: Final Results...

    Science.gov (United States)

    2010-03-22

    ... International Trade Administration (A-570-501) Natural Bristle Paint Brushes and Brush Heads from the People's... order on natural bristle paint brushes and brush heads from the People's Republic of China (``PRC...; Natural Bristle Paint Brushes and Brush Heads From the People's Republic of China, 51 FR 5580 (February 14...

  16. 75 FR 44939 - Natural Bristle Paint Brushes and Brush Heads from the People's Republic of China: Final Results...

    Science.gov (United States)

    2010-07-30

    ... Bristle Paint Brushes and Brush Heads from the People's Republic of China: Final Results of Changed... duty order on natural bristle paint brushes and brush heads from the People's Republic of China (``PRC... antidumping duty order on natural paint brushes and brush head in March 1986. See Antidumping Duty Order...

  17. Nanotribology of charged polymer brushes

    Science.gov (United States)

    Klein, Jacob

    Polymers at surfaces, whose modern understanding may be traced back to early work by Sam Edwards1, have become a paradigm for modification of surface properties, both as steric stabilizers and as remarkable boundary lubricants2. Charged polymer brushes are of particular interest, with both technological implications and especially biological relevance where most macromolecules are charged. In the context of biolubrication, relevant in areas from dry eye syndrome to osteoarthritis, charged polymer surface phases and their complexes with other macromolecules may play a central role. The hydration lubrication paradigm, where tenaciously-held yet fluid hydration shells surrounding ions or zwitterions serve as highly-efficient friction-reducing elements, has been invoked to understand the excellent lubrication provided both by ionized3 and by zwitterionic4 brushes. In this talk we describe recent advances in our understanding of the nanotribology of such charged brush systems. We consider interactions between charged end-grafted polymers, and how one may disentangle the steric from the electrostatic surface forces5. We examine the limits of lubrication by ionized brushes, both synthetic and of biological origins, and how highly-hydrated zwitterionic chains may provide extremely effective boundary lubrication6. Finally we describe how the lubrication of articular cartilage in the major joints, a tribosystem presenting some of the greatest challenges and opportunities, may be understood in terms of a supramolecular synergy between charged surface-attached polymers and zwitterionic groups7. Work supported by European Research Council (HydrationLube), Israel Science Foundation (ISF), Petroleum Research Fund of the American Chemical Society, ISF-NSF China Joint Program.

  18. Driver basado en procesador ARM 32 bits para un motor DC brushless de tres fases empleando la técnica de campo orientado

    OpenAIRE

    Flores Hornero, Pablo

    2017-01-01

    El siguiente proyecto consiste en el diseño y la implementación de un driver electrónico cuya principal función será la de realizar el control de un motor trifásico síncrono sin escobillas. Este tipo de motores son frecuentemente utilizados en la automatización de procesos industriales, por este motivo, el control de posición, velocidad y par de los mismos tiene vital importancia. Este proyecto nace sin un propósito de aplicación final concreta, simplemente pretende comprobar la validez de...

  19. DC electric springs with DC/DC converters

    DEFF Research Database (Denmark)

    Wang, Qingsong; Cheng, Ming; Jiang, Yunlei

    2016-01-01

    The concept of DC electric spring (DCES) was recently proposed to solve the stability issue caused by integrating intermittent renewable energy sources (RESs) to DC microgrids. In this paper, a new topology of DCES is proposed based on DC/DC converters. The proposed DCES consists of a bi-directio......The concept of DC electric spring (DCES) was recently proposed to solve the stability issue caused by integrating intermittent renewable energy sources (RESs) to DC microgrids. In this paper, a new topology of DCES is proposed based on DC/DC converters. The proposed DCES consists of a bi...

  20. Numerical simulation of dynamics of brushless dc motors for aerospace and other applications. Volume 2: User's guide to computer EMA model

    Science.gov (United States)

    Demerdash, N. A. O.; Nehl, T. W.

    1979-01-01

    A description and user's guide of the computer program developed to simulate the dynamics of an electromechanical actuator for aerospace applications are presented. The effects of the stator phase currents on the permanent magnets of the rotor are examined. The voltage and current waveforms present in the power conditioner network during the motoring, regenerative braking, and plugging modes of operation are presented and discussed.

  1. Numerical simulation of dynamics of brushless dc motors for aerospace and other applications. Volume 1: Model development and applications, part A

    Science.gov (United States)

    Demerdash, N. A. O.; Nehl, T. W.

    1979-01-01

    The development, fabrication and evaluation of a prototype electromechanical actuator (EMA) is discussed. Application of the EMA as a motor for control surfaces in aerospace flight is examined. A mathematical model of the EMA is developed for design optimization. Nonlinearities which complicate the mathematical model are discussed. The dynamics of the EMA from the underlying physical principles are determined and a discussion of similating the control logic by means of equivalent boolean expressions is presented.

  2. Diseño de controladores de tipo proporcional integral derivativo (PID) y difuso para la posición de un motor de corriente continua (DC)

    OpenAIRE

    Rairán Antolines, José Danilo; Guerrero Cifuentes, Cindy Estéfany; Mateus Pineda, Jaime Alfredo

    2010-01-01

    En este artículo se compara el desempeño de dos controladores —el proporcional integral derivativo (PID) y el difuso— sobre una plataforma comercial, utilizada normalmente en aeromodelismo, el servomotor Futaba S3004. Antes de realizar la identificación sobre el motor, se modifican el circuito de control, la etapa de potencia y el sensor. Enseguida se utiliza el método del lugar de las raíces para sintonizar el PID en el control de la posición angular. Las simulaciones y el control se realiza...

  3. Isolated step-down DC -DC converter for electric vehicles

    Science.gov (United States)

    Kukovinets, O. V.; Sidorov, K. M.; Yutt, V. E.

    2018-02-01

    Modern motor-vehicle industrial sector is moving rapidly now towards the electricity-driving cars production, improving their range and efficiency of components, and in particular the step-down DC/DC converter to supply the onboard circuit 12/24V of electric vehicle from the high-voltage battery. The purpose of this article - to identify the best circuitry topology to design an advanced step-down DC/DC converters with the smallest mass, volume, highest efficiency and power. And this will have a positive effect on driving distance of electric vehicle (EV). On the basis of computational research of existing and implemented circuit topologies of step-down DC/DC converters (serial resonant converter, full bridge with phase-shifting converter, LLC resonant converter) a comprehensive analysis was carried out on the following characteristics: specific volume, specific weight, power, efficiency. The data obtained was the basis for the best technical option - LLC resonant converter. The results can serve as a guide material in the process of components design of the traction equipment for electric vehicles, providing for the best technical solutions in the design and manufacturing of converting equipment, self-contained power supply systems and advanced driver assistance systems.

  4. Tooth brushing for oral prophylaxis

    Directory of Open Access Journals (Sweden)

    Haruaki Hayasaki, DDS, PhD

    2014-08-01

    Full Text Available Control of plaque and debris is essential for the prevention of inflammatory periodontal diseases and dental caries, because plaque is the primary etiological factor in the introduction and development of both of these infection-oriented diseases. Plaque removal with a toothbrush is the most frequently used method of oral hygiene. Powered toothbrushes were developed beginning in the 1960s and are now widely used in developed countries. The bristles of a toothbrush should be able to reach and clean efficiently most areas of the mouth, and recently the design of both manual and powered toothbrushes has focused on the ability to reach and clean interproximal tooth surfaces. An individual's tooth brushing behavior, including force, duration, motivation and motion, are also critical to tooth brushing efficacy. Dental floss and the type of toothpaste play additional important roles as auxiliary tools for oral prophylaxis. Dental professionals should help their care-receivers’ meet the requirements of oral hygiene to maintain their QOL. This article reviews these topics.

  5. An Integrated Multifunctional Bidirectional AC/DC and DC/DC Converter for Electric Vehicles Applications

    Directory of Open Access Journals (Sweden)

    Liwen Pan

    2016-06-01

    Full Text Available This paper presents an on-board vehicular battery charger that integrates bidirectional AC/DC converter and DC/DC converter to achieve high power density for application in electric vehicles (EVs. The integrated charger is able to transfer electrical energy between the battery pack and the electric traction system and to function as an AC/DC battery charger. The integrated charger topology is presented and the design of passive components is discussed. The control schemes are developed for motor drive system and battery-charging system with a power pulsation reduction circuit. Simulation results in MATLAB/Simulink and experiments on a 30-kW motor drive and 3.3-kW AC/DC charging prototype validate the performance of the proposed technology. In addition, power losses, efficiency comparison and thermal stress for the integrated charger are illustrated. The results of the analyses show the validity of the advanced integrated charger for electric vehicles.

  6. BSA adsorption on bimodal PEO brushes

    NARCIS (Netherlands)

    Bosker, WTE; Iakovlev, PA; Norde, W; Stuart, Martien A. Cohen

    2005-01-01

    BSA adsorption onto bimodal PEO brushes at a solid surface was measured using optical reflectometry. Bimodal brushes consist of long (N = 770) and short (N = 48) PEO chains and were prepared on PS surfaces, applying mixtures of PS29-PEO48 and PS37-PEO770 block copolymers and using the

  7. Step-Up DC-DC converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam P.; Gorji, Saman A.

    2017-01-01

    on the general law and framework of the development of next-generation step-up dc-dc converters, this paper aims to comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage...

  8. A prospective randomised study of dense Infinity cytological brush versus regularly used brush in pancreaticobiliary malignancy.

    Science.gov (United States)

    Kylänpää, Leena; Boyd, Sonja; Ristimäki, Ari; Lindström, Outi; Udd, Marianne; Halttunen, Jorma

    2016-01-01

    Endoscopic retrograde cholangiopancreatography (ERCP) with a cytological sample is a valuable tool in the diagnosis of the aetiology of biliary stricture. Our aim was to evaluate whether a more dense Infinity® cytological brush is more sensitive in diagnosing malignancy than the regularly used brush. We recruited 60 patients with a biliary stricture suspicious for malignancy for a randomised controlled trial. Patients were randomly assigned to an Infinity® brush group (n = 30) and a regularly used cytology brush group (n = 30). All the patients had verified cancer during follow-up. Crossing the brush over the stricture was possible in each case without dilatation of the biliary duct. Brush cytology yield was good or excellent in 86.7% of cases with the Infinity® brush and 96.7% with the regular brush (p = 0.161). The cytological sample showed clear malignancy in three patients (10.0%) in the Infinity® group and in 12 (40.0%) patients of the regular brush group (p = 0.007). The cytological diagnosis was highly suspicious for malignancy or malignant in 14 patients (46.7%) in the Infinity® group and in 23 patients (76.7%) in the regular brush group (p = 0.017). The result was benign in 10 patients (33.3%) in the Infinity® group and in four patients (13.6%) in the regular brush group (p = 0.067). With the standardised technique, the sensitivity of brush cytology is fairly good. The dense Infinity® brush does not show any advantage regarding sensitivity compared with the conventional cytology brush.

  9. Binary Polymer Brushes of Strongly Immiscible Polymers.

    Science.gov (United States)

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  10. [Tooth brushing in babies and toddlers].

    Science.gov (United States)

    de Groot-Nievaart, M A; Veerkamp, J S J

    2002-04-01

    The aim of this study was to investigate tooth brushing in toddlers and children younger than 4 years of age and the experiences of their parents. This study was performed in 3 towns in the middle of the Netherlands at the Office for Parent and Childcare. 99.4% of the children were brushed at least once a day during 0.5-1 minute. Tooth brushing is considered as a part of daily health care. Most children are cooperative and their parents enjoy brushing the teeth of their children. 17.5% of all parents experience problems with brushing teeth of their toddler or young child; 46% of them would like more information. But as the total number of children in a family increases, the parents' pleasure in brushing decreases. The Office for Parent and Childcare in the Netherlands has an important place in providing information on oral healthcare and especially tooth brushing for toddlers and children younger than 4 years of age. It would be useful to investigate how these healthcare workers get their dental information.

  11. Interfacial Friction and Adhesion of Polymer Brushes

    KAUST Repository

    Landherr, Lucas J. T.

    2011-08-02

    A bead-probe lateral force microscopy (LFM) technique is used to characterize the interfacial friction and adhesion properties of polymer brushes. Our measurements attempt to relate the physical structure and chemical characteristics of the brush to their properties as thin-film, tethered lubricants. Brushes are synthesized at several chain lengths and surface coverages from polymer chains of polydimethylsiloxane (PDMS), polystyrene (PS), and a poly(propylene glycol)-poly(ethylene glycol) block copolymer (PPG/PEG). At high surface coverage, PDMS brushes manifest friction coefficients (COFs) that are among the lowest recorded for a dry lubricant film (μ ≈ 0.0024) and close to 1 order of magnitude lower than the COF of a bare silicon surface. Brushes synthesized from higher molar mass chains exhibit higher friction forces than those created using lower molar mass polymers. Increased grafting density of chains in the brush significantly reduces the COF by creating a uniform surface of stretched chains with a decreased surface viscosity. Brushes with lower surface tension and interfacial shear stresses manifest the lowest COF. In particular, PDMS chains exhibit COFs lower than PS by a factor of 3.7 and lower than PPG/PEG by a factor of 4.7. A scaling analysis conducted on the surface coverage (δ) in relation to the fraction (ε) of the friction force developing from adhesion predicts a universal relation ε ∼ δ4/3, which is supported by our experimental data. © 2011 American Chemical Society.

  12. A resonant dc-dc power converter assembly

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a resonant DC-DC power converter assembly comprising a first resonant DC-DC power converter and a second resonant DC-DC power converter having identical circuit topologies. A first inductor of the first resonant DC-DC power converter and a second inductor of the s......The present invention relates to a resonant DC-DC power converter assembly comprising a first resonant DC-DC power converter and a second resonant DC-DC power converter having identical circuit topologies. A first inductor of the first resonant DC-DC power converter and a second inductor...

  13. Oral Health: Brush Up on Dental Care Basics

    Science.gov (United States)

    ... these brushing basics from the American Dental Association: Brush your teeth twice a day . When you brush, don't ... as a dental pick, pre-threaded flosser, tiny brushes that reach between teeth, a water flosser or wooden or silicone plaque ...

  14. A DC Transformer

    Science.gov (United States)

    Youngquist, Robert C.; Ihlefeld, Curtis M.; Starr, Stanley O.

    2013-01-01

    A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply can be stepped up (or down) with a corresponding step down (or up) in current. The basic theory for this device is developed, performance predictions are made, and the results from a small prototype are presented. Based on demonstrated technology in the literature, this de transformer should be scalable to low megawatt levels, but it is more suited to high current than high voltage applications. Significant development would be required before it could achieve the kilovolt levels needed for de power transmission.

  15. DC drive system for cine/pulse cameras

    Science.gov (United States)

    Gerlach, R. H.; Sharpsteen, J. T.; Solheim, C. D.; Stoap, L. J.

    1977-01-01

    Camera-drive functions are separated mechanically into two groups which are driven by two separate dc brushless motors. First motor, a 90 deg stepper, drives rotating shutter; second electronically commutated motor drives claw and film transport. Shutter is made of one piece but has two openings for slow and fast exposures.

  16. Brushless direct-current motors

    Science.gov (United States)

    Bahm, E. J.

    1970-01-01

    Survey results are presented on the use of unconventional motor windings and switching sequences to optimize performance of brushless dc motors. A motor was built, each coil terminal having a separate, accessible lead. With the shaft and all electronics excluded, length and outside diameter measured 1.25 and 0.75 in., respectively.

  17. Water driven turbine/brush pipe cleaner

    Science.gov (United States)

    Werlink, Rudy J. (Inventor)

    1995-01-01

    Assemblies are disclosed for cleaning the inside walls of pipes and tubes. A first embodiment includes a small turbine with angled blades axially mounted on one end of a standoff support. An O-ring for stabilizing the assembly within the pipe is mounted in a groove within the outer ring. A replaceable circular brush is fixedly mounted on the opposite end of the standoff support and can be used for cleaning tubes and pipes of various diameters, lengths and configurations. The turbine, standoff support, and brush spin in unison relative to a hub bearing that is fixedly attached to a wire upstream of the assembly. The nonrotating wire is for retaining the assembly in tension and enabling return of the assembly to the pipe entrance. The assembly is initially placed in the pipe or tube to be cleaned. A pressurized water or solution source is provided at a required flow-rate to propel the assembly through the pipe or tube. The upstream water pressure propels and spins the turbine, standoff support and brush. The rotating brush combined with the solution cleans the inside of the pipe. The solution flows out of the other end of the pipe with the brush rotation controlled by the flow-rate. A second embodiment is similar to the first embodiment but instead includes a circular shaped brush with ring backing mounted in the groove of the exterior ring of the turbine, and also reduces the size of the standoff support or eliminates the standoff support.

  18. Model Referans Uyarlanabilir Kontrole Dayalı Bulanık Kontrol Kullanımı ile DC Motor Sürücülerde Hız Kontrolünün Analiz ve Benzetimi

    Directory of Open Access Journals (Sweden)

    Ghazanfar SHAHGHOLIAN

    2016-09-01

    Full Text Available Bu makalede, model referans uyarlamalı kontrol (MRAC ve model referans bulanık uyarlanabilir kontrol (MRFAC için geleneksel performans sunulmuştur. Çalışmanın amaçları: a sistemin tanımlı referans model hızı ile motor hızının uyumunun arttırılması, b yükleme değişimi ve bozuklukları durumunda gürültünün azaltılması ve c sistemin kararlılığının arttırılması. Böylece, model referans uyarlamalı kontrol yerine uyarlanabilir olmayan veya geleneksel kontrol uygulanır.Ayrıca bulanık kontrolör, PI kontrolör gibi klasik kontrolörlerin yerine kullanılmıştır. Uyarlanır olmayan kontrolün işletimi ve model referans bulanık kontrol ve geleneksel uyarlanabilir kontrol, dc motor hızının türetilmesi ve ayarlanmasında çalışılmıştır. Ardından bunlar birbirleriyle karşılaştırılmıştır. Model referans ve bulanık kontrolör, tüm sistemin kararlılık güvencesine dayanarak tasarlanmıştır. Simülasyon, sabit ve değişken yükler ile yapılmıştır. Elde edilen sonuçlara göre, uyarlanabilir kontrol, uyarlanabilir olmayana göre daha gözdedir. Ayrıca bulanık uyarlanabilir kontrol geleneksel uyarlanabilir kontrolden daha tatmin edicidir.Simülasyonlar, Matlab-Simulink kullanılarak yapılmıştır

  19. Application of tooth brushing behavior to active rest.

    Science.gov (United States)

    Sadachi, Hidetoshi; Murakami, Yoshinori; Tonomura, Manabu; Yada, Yukihiro; Simoyama, Ichiro

    2010-01-01

    We evaluated the usefulness of tooth brushing with toothpaste as active rest using the flicker value as a physiological parameter and a subjective questionnaire as a psychological parameter. Seventeen healthy, right-handed subjects (12 males and 5 females) aged 22.5 +/- 1.5 yr (mean +/- standard deviation) were randomly divided into tooth brushing with toothpaste (N=9) and non-tooth brushing groups (N=8). The subjects performed a serial calculation task for 20 min using personal computers. Subsequently, the tooth brushing group brushed their teeth, and the flicker value and mood were compared before and after the tooth brushing. The flicker value significantly increased in the tooth brushing group compared with the non-tooth brushing group (pbrushing group, the incidence of a "feeling of being refreshed" significantly increased (pbrushing activated cerebral activity, producing refreshing effects. These results suggest the applicability of tooth brushing to active rest.

  20. Stratified polymer brushes from microcontact printing of polydopamine initiator on polymer brush surfaces.

    Science.gov (United States)

    Wei, Qiangbing; Yu, Bo; Wang, Xiaolong; Zhou, Feng

    2014-06-01

    Stratified polymer brushes are fabricated using microcontact printing (μCP) of initiator integrated polydopamine (PDOPBr) on polymer brush surfaces and the following surface initiated atom transfer radical polymerization (SI-ATRP). It is found that the surface energy, chemically active groups, and the antifouling ability of the polymer brushes affect transfer efficiency and adhesive stability of the polydopamine film. The stickiness of the PDOPBr pattern on polymer brush surfaces is stable enough to perform continuous μCP and SI-ATRP to prepare stratified polymer brushes with a 3D topography, which have broad applications in cell and protein patterning, biosensors, and hybrid surfaces. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Bidirectional Brush Seals: Post-Test Analysis

    Science.gov (United States)

    Hendricks, Robert C.; Wilson, Jack; Wu, Tom Y.; Flower, Ralph; Mullen, Robert L.

    1997-01-01

    A post-test analysis of a set of inside-diameter/outside-diameter (ID/OD) bidirectional brush seals used in three-port wave rotor tests was undertaken to determine brush bristle and configuration wear, pullout, and rotor coating wear. The results suggest that sharp changes in the pressure profiles were not well reflected in bristle tip configuration patterns or wear. Also, positive-to-negative changes in axial pressure gradients appeared to have little effect on the backing plates. Although the brushes had similar porosities, they had very different unpacked arrays. This difference could explain the departure of experimental data from computational fluid dynamics flow predictions for well-packed arrays at higher pressure drops. The rotor wear led to "car-track" scars (upper and lower wear bands) with a whipped surface between the bands. Those bands may have resulted from bristle stiffening at the fence and gap plates during alternate portions of the rotor cycle. Within the bristle response range the wear surface reflected the pressure distribution effect on bristle motion. No sacrificial metallurgical data were taken. The bristles did wear, with correspondingly more wear on the ID brush configurations than on the OD configurations; the complexity in constructing the ID brush was a factor.

  2. Soft switched DC-DC converter

    Science.gov (United States)

    Subramanian, K.; Kavitha, K. V. N.; Saravanan, K.

    2017-11-01

    A soft switched single switch isolated dc-dc conveys proposed in this paper. This converter works on the principle of zero current switching (zcs) and zero voltage switching (zvs). The circuit comprises lossless snubber with low rating. The switch works on zcs during turn on and zvs during turnoff. The diodes are based on zcs turn on and turnoff conditions. This paper presents the concept of soft switching and its applications to dc-dc converter. The losses due to soft switching and hard switching are compared.

  3. IGBT Based DC/DC Converter

    Directory of Open Access Journals (Sweden)

    M. Akherraz

    1997-12-01

    Full Text Available This paper presents an in-depth analytical and experimental investigation of an indirect DC-DC converter. The DC-AC conversion is a full bridge based on IGBT power modules, and the AC-DC conversion is done via a high  frequency AC link and a first diode bridge. The AC link, which consists of snubbing capacitors and a variable air-gap transformer, is analytically designed to fulfill Zero Voltage commutation requirement. The proposed converter is simulated using PSPICE and a prototype is designed built and tested in the laboratory. PSPICE simulation and experimental results are presented and compared.

  4. Pengaturan Kecepatan Putaran Motor Dc Berbasis Komputer

    OpenAIRE

    Anshori, Yusuf

    2009-01-01

    The development of industrial world needs an instrumentation automation that to support production process. For a true intelligent and flexible automated manufacturing system, the system should be able to respond to changing conditions by changing the manufacturing process all by itself. Computers can be programmed to "read" external conditions and to execute different parts of their programs depending on the sensed conditions. Computers will require additional interface cards like PPI 8255 a...

  5. Self-Assembling Brush Polymers Bearing Multisaccharides.

    Science.gov (United States)

    Lee, Jongchan; Kim, Jin Chul; Lee, Hoyeol; Song, Sungjin; Kim, Heesoo; Ree, Moonhor

    2017-06-01

    Three different series of brush polymers bearing glucosyl, maltosyl, or maltotriosyl moiety at the bristle end are successfully prepared by using cationic ring-opening polymerization and two sequential postmodification reactions. All brush polymers, except for the polymer containing 100 mol% maltotriosyl moiety, demonstrate the formation of multibilayer structure in films, always providing saccharide-enriched surface. These self-assembling features are remarkable, regarding the bulkiness of saccharide moieties and the kink in the bristle due to the triazole linker. The saccharide-enriched film surfaces reveal exceptionally high specific binding affinity to concanavalin A but suppress nonspecific binding of plasma proteins severely. Overall, the brush polymers bearing saccharide moieties of various kinds in this study are highly suitable materials for biomedical applications including biosensors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Parents' reasons for brushing or not brushing their child's teeth: a qualitative study.

    Science.gov (United States)

    Trubey, Rob J; Moore, Simon C; Chestnutt, Ivor G

    2014-03-01

    Despite recent improvements in oral health, dental caries remains a significant source of morbidity for young children. Research has shown that regular toothbrushing with fluoride toothpaste reduces the risk of dental caries, but the factors that influence parental decisions about whether or not to brush their infant children's teeth at home are poorly understood. To develop an in-depth understanding of the issues that parents face from socio-economically deprived areas when trying to brush their young children's teeth at home. Fifteen parents of children aged 3-6 years took part in semi-structured telephone interviews, discussing factors relating to brushing their child's teeth at home. Thematic analysis was used to develop three themes. Parents discussed the difficulty of brushing their children's teeth in the evening, due to changing day-to-day routines, and the subsequent difficulty of forming a toothbrushing habit. Motivating factors for brushing children's teeth were largely short term. Satisfaction with brushing frequency was influenced more by perceptions of how often other parents brushed children's teeth than by the 'twice a day' norm or health outcomes. Results are discussed in relation to research and theories from the psychology and behavioural economics literature, and comparisons are drawn with assumptions inherent in more traditional oral health promotion messages. © 2013 John Wiley & Sons Ltd, BSPD and IAPD.

  7. Dimeric assembly of enterocyte brush border enzymes

    DEFF Research Database (Denmark)

    Danielsen, E M

    1994-01-01

    The noncovalent, dimeric assembly of small intestinal brush border enzymes was studied by sedimentation analysis in density gradients of extracts of pulse-labeled pig jejunal mucosal explants. Like aminopeptidase N (EC 3.4.11.2), sucrase-isomaltase (EC 3.2.1.48-10), aminopeptidase A (EC 3...... appearance of the liposome-reconstituted enzyme [Norén et al. (1986) J. Biol. Chem. 261, 12306-12309], showing only the inner, membrane-anchored domains of the monomers to be in close contact with one another while the outer domains are far apart. In contrast to the other brush border enzymes studied...

  8. Interfacial properties of bottle-brush polyelectrolytes

    DEFF Research Database (Denmark)

    Claesson, P. M.; Naderi, A.; Iruthayaraj, J.

    2007-01-01

    This article is focused on interfacial properties of bottle brush polyelectrolytes, where side-chains are attached along a polymer backbone. This class of polymer has been much less studied than block copolymers, which is particularly true for bottle brush polyelectrolytes with a high graft density...... whereas on silica both electrostatic forces and interactions between silica and ethylene oxide chains drive the adsorption. On silica the adsorbed amount is very sensitive to solution ionic strength and pH. We also report on surface interactions and frictional forces obtained between surfaces coated...

  9. Antifouling Properties of Fluoropolymer Brushes toward Organic Polymers

    NARCIS (Netherlands)

    Wang, Zhanhua; Zuilhof, Han

    2016-01-01

    Fluoropolymer brushes are widely used to prevent nonspecific adsorption of commercial polymeric or biological materials due to their strongly hydrophobic character. Herein, a series of fluoropolymer brushes with different compositions, thicknesses and molecular architectures was prepared via

  10. Design and implementation of a bidirectional current-controlled voltage-regulated DC-DC switched-mode converter

    CSIR Research Space (South Africa)

    Coetzer, A

    2016-01-01

    Full Text Available The design and implementation of a bidirectional current-controlled voltage-regulated DC-DC converter is presented. The converter is required to connect a battery of electrochemical cells (the battery) to an asynchronous motor-drive unit via a...

  11. Synthesis and characterization of metal oxide nanorod brushes

    Indian Academy of Sciences (India)

    Nanorod brushes of -Al2O3, MoO3 and ZnO have been synthesized using amorphous carbon nanotube (-CNT) brushes as the starting material. The brushes of -Al2O3 and MoO3 are made up of single crystalline nanorods. In the case of ZnO brushes, the nanorod bristles are made by the fusion of 15–25 nm size ...

  12. Social ranking effects on tooth-brushing behaviour

    OpenAIRE

    Maltby, John; Paterson, Kevin; Day, Liz; Jones, Ceri; Kinnear, Hayley; Buchanan, Heather

    2016-01-01

    Objective: A tooth-brushing social rank hypothesis is tested suggesting tooth-brushing duration is influenced when individuals position their behaviour in a rank when comparing their behaviour with other individuals.\\ud Design: Study 1 used a correlation design, Study 2 used a semi-experimental design, and Study 3 used a randomized intervention design to examine the tooth-brushing social rank hypothesis in terms of self-reported attitudes, cognitions, and behaviour towards tooth-brushing dura...

  13. FreedomCAR Advanced Traction Drive Motor Development Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Ley, Josh (UQM Technologies, Inc.); Lutz, Jon (UQM Technologies, Inc.)

    2006-09-01

    The overall objective of this program is to design and develop an advanced traction motor that will meet the FreedomCAR and Vehicle Technologies (FCVT) 2010 goals and the traction motor technical targets. The motor specifications are given in Section 1.3. Other goals of the program include providing a cost study to ensure the motor can be developed within the cost targets needed for the automotive industry. The program has focused on using materials that are both high performance and low costs such that the performance can be met and cost targets are achieved. In addition, the motor technologies and machine design features must be compatible with high volume manufacturing and able to provide high reliability, efficiency, and ruggedness while simultaneously reducing weight and volume. Weight and volume reduction will become a major factor in reducing cost, material cost being the most significant part of manufacturing cost at high volume. Many motor technology categories have been considered in the past and present for traction drive applications, including: brushed direct current (DC), PM (PM) brushless dc (BLDC), alternating current (AC) induction, switched reluctance and synchronous reluctance machines. Of these machine technologies, PM BLDC has consistently demonstrated an advantage in terms of power density and efficiency. As rare earth magnet cost has declined, total cost may also be reduced over the other technologies. Of the many different configurations of PM BLDC machines, those which incorporate power production utilizing both magnetic torque as well as reluctance torque appear to have the most promise for traction applications. There are many different PM BLDC machine configurations which employ both of these torque producing mechanisms; however, most would fall into one of two categories--some use weaker magnets and rely more heavily on reluctance torque (reluctance-dominant PM machines), others use strong PMs and supplement with reluctance torque

  14. Brushes and soap : grafted polymers and their interactions with nanocolloids

    NARCIS (Netherlands)

    Currie, E.P.K.

    2000-01-01

    Layers of polymer chains end-attached to a grafting plane at high densities, so-called brushes, are a curious state of matter. The (average) monomer density within the brush is as high as in a semi-dilute polymer solution, resulting in a high osmotic pressure in the brush. Due to the

  15. Switching the Interpenetration of Confined Asymmetric Polymer Brushes

    NARCIS (Netherlands)

    Abbott, Stephen B.; de Vos, Wiebe Matthijs; Mears, Laura L.E.; Skoda, Maximilian W.A.; Dalgliesh, Robert; Edmondson, Steve; Richardson, Robert M.; Prescott, Stuart W.

    2016-01-01

    The interpenetration of two polymer brushes on approaching flat surfaces has been investigated. When compacting polymer brushes with an asymmetric charge on each surface, one neutral and the other weakly charged, we find that the brush interpenetration becomes a parameter that can be controlled by

  16. Increasing operational life of brush-contact device in the turbine generator due to using lubricating molybdenum disulphide brushes

    Science.gov (United States)

    Izotov, A. I.; Fominykh, A. A.; Nikulin, S. V.; Prokoshev, D. K.; Legoti, A. B.; Timina, N. V.

    2018-01-01

    A way of reducing irregular current distribution in multi-brush systems of sliding current transfer with its wear reduction due to installing lubricating molybdenum disulphide brushes on slip rings to ensure a greasing nano-sized cover on the slip ring surface is proposed. The authors give the results of industrial tests estimated on the performance effectiveness of lubricating brushes on slip rings of the TBB-320-2UZ-type turbine generator. The results showed that the lubricating brushes reduce a) the wear of 6110 OM+M and EG2AF+M brushes by 1.2 and 2.1 times respectively, b) current distribution irregularity in parallel operating brushes due to stabilizing the contact arc, and c) the temperature of the electrical brush-contact device due to the friction reduction in brushes.

  17. Speed Control of Bldc Motor Drive By Using Pid Controllers

    OpenAIRE

    Y.Narendra Kumar,; P.Eswara Rao

    2014-01-01

    This paper mainly deals with the Brushless DC (BLDC) motor speed driving systems have sprouted in various small scale and large scale applications like automobile industries, domestic appliances etc. This leads to the development in Brushless DC motor (BLDCM). The usage of BLDC Motor enhances various performance factors ranging from higher efficiency, higher torque in low-speed range, high power density ,low maintenance and less noise than other motors. The BLDC Motor can act ...

  18. Design and Testing of High Performance Brushes.

    Science.gov (United States)

    1982-03-01

    Electric Brushes SARA DILLICH AND DORIS KUHLMANN-WILSDORF Abi Vtcv-The brus resitance of silver graphite (Stackpole SG142, 75 TABLE I wt% All, 25 wt...the performance of Stackpole SG 142 sliding contacts themselves produce (75 w/o Ag, 25 w/o C) silver graphite heat and are thus prone to introduce

  19. Responsive polymer brushes for biomedical applications

    NARCIS (Netherlands)

    Akkilic, Namik; de Vos, Wiebe Matthijs; Zhang, Johnathan

    2015-01-01

    The development of biomedical devices, biosensors, and medical implants is critically dependent on the engineering of “smart” surfaces that can adapt or respond to their local environment. The responsive polymer brush can be considered one of the most promising systems to create such smart surfaces.

  20. Cigarette smoking, tooth brushing characteristics, and perceived ...

    African Journals Online (AJOL)

    This study was conducted among four hundred non-dental undergraduates of University of Benin, Benin City, Nigeria to assess the prevalence of cigarette smoking, tooth brushing characteristics, perceived efficacy in oral self-care and preventing gingivodental diseases among them. The result showed that the perceived ...

  1. Chinese Brush Calligraphy Character Retrieval and Learning

    Science.gov (United States)

    Zhuang, Yueting; Zhang, Xiafen; Lu, Weiming; Wu, Fei

    2007-01-01

    Chinese brush calligraphy is a valuable civilization legacy and a high art of scholarship. It is still popular in Chinese banners, newspaper mastheads, university names, and celebration gifts. There are Web sites that try to help people enjoy and learn Chinese calligraphy. However, there lacks advanced services such as content-based retrieval or…

  2. 76 FR 31462 - Airworthiness Directives; The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10...

    Science.gov (United States)

    2011-06-01

    ... Model DC-10-10, DC- 10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... Applicability (c) This AD applies to all The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10- 40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F airplanes...

  3. Sensorless Control of PM Synchronous Motors and Brushless DC Motors

    DEFF Research Database (Denmark)

    Montesinos, D.; Galceran, Samuel; Blaabjerg, Frede

    2005-01-01

    This paper provides a review of the literature addressing sensorless operation methods of PM brushless machines. The methods explained are state-of-the-art of open and closed loop control strategies. The closed loop review includes those methods based on voltage and current measurements, those me...

  4. FLYWHEEL AND A DC MACHINE

    Directory of Open Access Journals (Sweden)

    IVAN ALCALÁ

    2014-01-01

    Full Text Available Este artículo describe el análisis, modelado y simulación de un vehículo eléctrico (EV enfocado al desarrollo de un banco de pruebas para reproducir la dinámica del EV. El banco está formado por un drive de motor de inducción (IM acoplado directamente a una máquina de DC y a un volante de inercia a través de una transmisión. El volante de inercia y la máquina de DC reproducen la dinámica y las fuerzas que actúan en el vehículo. Se propone una metodología para diseñar un banco de pruebas de EV para estudiar el comportamiento de vehículos eléctricos cercano a las condiciones de operación reales. El análisis de las fuerzas en el EV en conjunto con la máquina DC define las condiciones de operación del EV. El modelado y la simulación son desarrollados en MATLAB/Simulink, el banco de pruebas implementado es controlado por un DSP. Finalmente, los resultados de simulación y experimentales obtenidos validan el funcionamiento del banco de prueba.

  5. Sensorless Control of Electric Motors with Kalman Filters: Applications to Robotic and Industrial Systems

    Directory of Open Access Journals (Sweden)

    Gerasimos G. Rigatos

    2011-12-01

    Full Text Available The paper studies sensorless control for DC and induction motors, using Kalman Filtering techniques. First the case of a DC motor is considered and Kalman Filter-based control is implemented. Next the nonlinear model of a field-oriented induction motor is examined and the motor

  6. Variable-frequency inverter controls torque, speed, and braking in ac induction motors

    Science.gov (United States)

    Nola, F. J.

    1974-01-01

    Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

  7. Fouling-resistant polymer brush coatings

    KAUST Repository

    Thérien-Aubin, Héloïse

    2011-11-01

    A major problem to be addressed with thin composite films used in processes such as coatings or water purification is the biofouling of the surface. To address this problem in a model system, functionalized polyaramide membranes containing an atom transfer radical polymerization (ATRP) initiator were synthesized as a versatile approach to easily modify the surface properties of the polyaramide. Poly(methacrylic acid) brushes were grown using surface initiated ATRP followed by the functionalization of the poly(methacrylic acid) brushes with different side-chains chosen to reduce adhesion between the membrane and foulant. The relation between membrane fouling and the physicochemical properties of the surface was investigated in detail. © 2011 Elsevier Ltd. All rights reserved.

  8. Antifouling polymer brushes displaying antithrombogenic surface properties

    Czech Academy of Sciences Publication Activity Database

    de los Santos Pereira, Andres; Sheikh, S.; Blaszykowski, C.; Pop-Georgievski, Ognen; Fedorov, K.; Thompson, M.; Rodriguez-Emmenegger, Cesar

    2016-01-01

    Roč. 17, č. 3 (2016), s. 1179-1185 ISSN 1525-7797 R&D Projects: GA ČR(CZ) GJ15-09368Y; GA MŠk(CZ) ED1.1.00/02.0109 Grant - others:OPPK(XE) CZ.2.16/3.1.00/21545 Program:OPPK Institutional support: RVO:61389013 Keywords : polymer brushes * surface characterization * antifouling surfaces Subject RIV: BO - Biophysics Impact factor: 5.246, year: 2016

  9. Torque-Summing Brushless Motor

    Science.gov (United States)

    Vaidya, J. G.

    1986-01-01

    Torque channels function cooperatively but electrically independent for reliability. Brushless, electronically-commutated dc motor sums electromagnetic torques on four channels and applies them to single shaft. Motor operates with any combination of channels and continues if one or more of channels fail electrically. Motor employs single stator and rotor and mechanically simple; however, each of channels electrically isolated from other so that failure of one does not adversely affect others.

  10. Metastatic urachal carcinoma in bronchial brush cytology

    Directory of Open Access Journals (Sweden)

    Fatima Zahra Aly

    2013-01-01

    Full Text Available Urachal carcinoma is rare comprising less than 1% of all bladder carcinomas. Metastases of urachal carcinoma have been reported to meninges, brain, ovary, lung, and maxilla. Cytologic features of metastatic urachal carcinoma have not been previously reported. We present a case of metastatic urachal adenocarcinoma in bronchial brushings and review the use of immunohistochemistry in its diagnosis. A 47-year-old female was seen initially in 2007 with adenocarcinoma of the bladder dome for which she underwent partial cystectomy. She presented in 2011 with a left lung mass and mediastinal adenopathy. Bronchoscopy showed an endobronchial lesion from which brushings were obtained. These showed numerous groups of columnar cells with medium sized nuclei and abundant cytoplasm. The cells were positive for CK20 and CDX2 and negative for CK7. The cytomorphological findings were similar to those in the previous resection specimen and concurrent biopsy. This is the first case report of bronchial brushings containing metastatic urachal carcinoma. No specific immunohistochemical profile is available for its diagnosis. The consideration of a second primary was a distinct possibility in this case due to the lapse of time from primary resection, absence of local disease, and lack of regional metastases.

  11. Dynamics of Brush-grafted Nanoparticles in Polymer Melts

    Science.gov (United States)

    Composto, Russell; Lin, Chia-Chun; Ohno, Kohji; Hore, Michael; Meth, Jeffrey; Clarke, Nigel; Winey, Karen

    2015-03-01

    Grafting a polymer brush to nanoparticles is an effective approach to achieve a good dispersion of nanoparticles in a polymer melt and the structure of this dispersion has been well studied. However, the interplay between the structure of the brush and nanoparticle diffusion is lacking. Here, we study the diffusion of poly (methyl methacrylate), or PMMA,-grafted iron oxide nanoparticles (core diameter=5nm) in PMMA melts. Different brush architectures are obtained by tuning brush molecular weight (16 and 21kg/mol), brush grafting density (0.17, 0.33 and 0.55 chains/nm2) and PMMA matrix molecular weight (4-70kg/mol). Preliminary results show that the diffusion of nanoparticles is slowed down relative to predictions of the classic Stokes-Einstein relation applied to a 5nm particle suggesting that the interpenetration between the brush and matrix influences nanoparticle mobility. Self-consistent field theory is performed to predict the structure of brush and matrix in the vicinity of the particle to quantify the effect of brush-matrix interpenetration. These experiments demonstrate that the structure of the brush could affect nanoparticle center of mass diffusion and the brush-nanoparticle interpenetration should be considered. Primary supports from NSF/EPSRC Materials World Network DMR 1210379 (KIW, RJC) and EP/5065373/1 (NC).

  12. DC-to-DC switching converter

    Science.gov (United States)

    Cuk, Slobodan M. (Inventor); Middlebrook, Robert D. (Inventor)

    1980-01-01

    A dc-to-dc converter having nonpulsating input and output current uses two inductances, one in series with the input source, the other in series with the output load. An electrical energy transferring device with storage, namely storage capacitance, is used with suitable switching means between the inductances to DC level conversion. For isolation between the source and load, the capacitance may be divided into two capacitors coupled by a transformer, and for reducing ripple, the inductances may be coupled. With proper design of the coupling between the inductances, the current ripple can be reduced to zero at either the input or the output, or the reduction achievable in that way may be divided between the input and output.

  13. Professional brushing study comparing the effectiveness of sonic brush heads with manual toothbrushes: a single blinded, randomized clinical trial.

    Science.gov (United States)

    Pelka, Anna-Kristina; Nagler, Tonia; Hopp, Imke; Petschelt, Anselm; Pelka, Matthias Anton

    2011-08-01

    The aim of this study was to evaluate the plaque removal efficacy of four toothbrushes: the Philips Sonicare Elite with medium and mini brush heads, the Elmex Sensitive, and the American Dental Association (ADA) reference toothbrush. This study was a randomized, controlled, investigator-blinded, four-brush crossover design study, which examined plaque removal following a consecutive repeated use. All brushes were used on each participant in a randomly assigned quadrant of the mouth. A total of 90 subjects participated in the study. Prior to the experiment, they received a professional prophylaxis and were requested to refrain from toothbrushing for 48 h. Teeth were professionally brushed consecutively for 10 to 90 s per quadrant. A Turesky-modified Quigley Hein Index score was assessed at baseline and after each brushing interval by one blinded investigator. Results showed reduction of mean plaque scores for all brushes with time from 10 to 90 s. After 30 s (2-min whole mouth equivalent) of brushing, the Sonicare brushes cleaned 19, the ADA brush 16, and the Elmex Sensitive 10 of in average 28 tooth surfaces. With time, the number of additional cleaned surfaces decreased. Time is an important variable in the evaluation of plaque-removing efficacy since absolute efficacy increases with time and differs per toothbrush. No differences could be found between the two brush heads of the Sonicare.

  14. DC-Link Compensation Method for Slim DC Link Drives Fed by Soft Grid

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Rosendahl Andersen, Henrik; Lazar, Radu

    2010-01-01

    Slim DC-link PWM (AC) drives for lowperformance applications are emerging on the market. Such drives equipped with a small DC-link capacitance exhibit instability tendencies, if installed on a soft line, giving a degraded performance. The total harmonic distortion (THD) and the partially weighted...... method, which ensures the stability of the slim DC-link on a soft grid. The proposed compensation method may be used for open- and closedloop control schemes, requiring a small overhead in the digital implementation.......Slim DC-link PWM (AC) drives for lowperformance applications are emerging on the market. Such drives equipped with a small DC-link capacitance exhibit instability tendencies, if installed on a soft line, giving a degraded performance. The total harmonic distortion (THD) and the partially weighted...... harmonic distortion (PWHD) of the line current are degraded, if resonance between the line impedance and the DC-link capacitance occurs. Likewise, the motor performance is affected negatively giving extra torque ripple, vibration and acoustic-noise emission. This paper proposes a novel DC-link compensation...

  15. [Clinical relevance of tooth brushing in relation to dental caries].

    Science.gov (United States)

    Pita-Fernández, Salvador; Pombo-Sánchez, Antonio; Suárez-Quintanilla, Juan; Novio-Mallón, Silvia; Rivas-Mundiña, Berta; Pértega-Díaz, Sonia

    2010-07-01

    To determine the impact and clinical relevance of tooth brushing on oral health. Prevalence study. Fontiñas Health Centre. (Santiago de Compostela, Spain). Prevalence study (n=281 children aged 5-14 years. Odontological examination according to WHO methodology, to determine the frequency of tooth brushing, frequency of sweet consumption and their impact on the prevalence of caries. Logistic regression and estimation of the relative prevalence difference (RPD) and the Number Needed to Treat in order to prevent one additional bad outcome (NNT). The children who never brush their teeth have a 40% (95% CI: 24.3%-57.8%) of early caries, while those who brush their teeth several times a day have 15.3% (95% CI: 9.4%-23.7%). An association between not brushing the teeth and caries in primary teeth (OR=2.3; 95% CI:1.05-5.3) was observed after adjusting for age, sweet consumption and visits to the dentist. The same occurred with final teeth (OR=3.9; 95% CI:1.4-10.3). The RPD was 62%(95% CI: 30%-79%), meaning that prevalence of caries is 62% lower in children who brush their teeth several times a day as compared to those who never brush their teeth. The NNT is 4 (95% CI: 2.4-14), so for every 4 children who brush their teeth several times a day, there is one less case of caries, compared to those who never brush their teeth. There is a dose-response relationship between prevalence of caries and brushing frequency. The same effect was observed with definitive caries: RPD=55% (95% CI:16%-76%), NNT=5 (95% CI:2.8-53.3). Tooth brushing is related to oral health, with a major clinical impact. The positive effect of tooth brushing was superior to that of a correct diet. 2009 Elsevier España, S.L. All rights reserved.

  16. Social ranking effects on tooth-brushing behaviour.

    Science.gov (United States)

    Maltby, John; Paterson, Kevin; Day, Liz; Jones, Ceri; Kinnear, Hayley; Buchanan, Heather

    2016-05-01

    A tooth-brushing social rank hypothesis is tested suggesting tooth-brushing duration is influenced when individuals position their behaviour in a rank when comparing their behaviour with other individuals. Study 1 used a correlation design, Study 2 used a semi-experimental design, and Study 3 used a randomized intervention design to examine the tooth-brushing social rank hypothesis in terms of self-reported attitudes, cognitions, and behaviour towards tooth-brushing duration. Study 1 surveyed participants to examine whether the perceived health benefits of tooth-brushing duration could be predicted from the ranking of each person's tooth-brushing duration. Study 2 tested whether manipulating the rank position of the tooth-brushing duration influenced participant-perceived health benefits of tooth-brushing duration. Study 3 used a longitudinal intervention method to examine whether messages relating to the rank positions of tooth-brushing durations causally influenced the self-report tooth-brushing duration. Study 1 demonstrates that perceptions of the health benefits from tooth-brushing duration are predicted by the perceptions of how that behaviour ranks in comparison to other people's behaviour. Study 2 demonstrates that the perceptions of the health benefits of tooth-brushing duration can be manipulated experimentally by changing the ranked position of a person's tooth-brushing duration. Study 3 experimentally demonstrates the possibility of increasing the length of time for which individuals clean their teeth by focusing on how they rank among their peers in terms of tooth-brushing duration. The effectiveness of interventions using social-ranking methods relative to those that emphasize comparisons made against group averages or normative guidelines are discussed. What is already known on this subject? Individual make judgements based on social rank information. Social rank information has been shown to influence positive health behaviours such as exercise

  17. Antifouling Properties of Fluoropolymer Brushes toward Organic Polymers: The Influence of Composition, Thickness, Brush Architecture, and Annealing.

    Science.gov (United States)

    Wang, Zhanhua; Zuilhof, Han

    2016-07-05

    Fluoropolymer brushes are widely used to prevent nonspecific adsorption of commercial polymeric or biological materials due to their strongly hydrophobic character. Herein, a series of fluoropolymer brushes with different compositions, thicknesses and molecular architectures was prepared via surface-initiated atom transfer radical polymerization (ATRP). Subsequently, the antifouling properties of these fluoropolymer brushes against organic polymers were studied in detail using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements and polystyrene as a representative fouling polymer. Among all of the molecular architectures studied, homopolymerized methacrylate-based fluoropolymer brushes (PMAF17) show the best antifouling properties. Annealing the fluoropolymer brushes improves the antifouling property dramatically due to the reregulated surface composition. These fluoropolymer brushes can be combined with, e.g., micro- and nanostructuring and other advanced materials properties to yield even better long-term antifouling behavior under harsh environments.

  18. Battery-driven motor arrangement. [design to prevent hydrogen explosions

    Energy Technology Data Exchange (ETDEWEB)

    Mabuchi, K.

    1976-01-15

    Hydrogen can escape from nickel--cadmium batteries. If they are used in conventional battery operated motor arrangements, there is then a danger of oxyhydrogen gas explosions if the hydrogen penetrates into spaces in which oxyhydrogen gas can be ignited by switch-on and switch-off arcs of electrical contacts or motor brushes. The present invention removes this danger by suitable construction of the battery--motor casing and the contacts.

  19. 75 FR 38943 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-30, DC...

    Science.gov (United States)

    2010-07-07

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10-40F Airplanes AGENCY... propose to adopt a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10- 40, and DC-10-40F airplanes. This proposed AD would require installing a support...

  20. 75 FR 63040 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-30, DC...

    Science.gov (United States)

    2010-10-14

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10-40F Airplanes AGENCY... (b) None. Applicability (c) This AD applies to McDonnell Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-30, DC-10-30F (KDC-10), DC-10-40, and DC-10- 40F airplanes, certificated in any category...

  1. Polymer absorption in dense polymer brushes vs. polymer adsorption on the brush-solvent interface

    Science.gov (United States)

    Milchev, Andrey; Binder, Kurt

    2014-06-01

    Molecular-dynamics simulations of a coarse-grained model of a dense brush of flexible polymers (of type A) interacting with a long flexible macromolecule (of type B) are presented, considering the case of an attractive AB interaction, while effective interactions between AA and BB pairs of monomers are repulsive. Varying the strength \\varepsilon_{AB} of the attraction between unlike monomers, an adsorption transition at some critical value \\varepsilon^c_{AB} is found, where the B-chain is bound to the brush-solvent interface, similar to the adsorption on a planar solid substrate. However, when \\varepsilon_{AB} is much higher than \\varepsilon^c_{AB} , the long macromolecule is gradually “sucked in” the brush, developing many pieces that are locally stretched in the z-direction perpendicular to the substrate, in order to fit between the brush chains. The resulting hairpin-like structures of the absorbed chain shows up via oscillatory decay of the bond vector autocorrelation function. Chain relaxation is only possible via reptation.

  2. Efficiency Characteristics of Low Power Hybrid Switched Reluctance Motor

    DEFF Research Database (Denmark)

    Jakobsen, Uffe; Ahn, Jin-Woo

    2009-01-01

    Switched reluctance motors (SRM) are usually considered inferior in terms of efficiency as compared to permanent magnet synchronous motors (PMSM) and brushless DC-motors (BLDC), but less costly. This article presents a test of a 70W hybrid switched reluctance motor (HSRM), that archieves a peak e...

  3. Effect of Frequency of Brushing Teeth on Plaque and Calculus Accumulation, and Gingivitis in Dogs.

    Science.gov (United States)

    Harvey, Colin; Serfilippi, Laurie; Barnvos, Donald

    2015-01-01

    The efficacy of brushing the teeth of beagle dogs in a randomized, controlled, blinded study design using a clearly-defined brushing technique was evaluated for 4 brushing frequencies: brushing daily, brushing every other day, brushing weekly and brushing every other week, compared with no brushing in a control group of dogs. All dogs were fed a standard dry kibble diet during the study. Standard plaque, calculus, and gingivitis indices were used to score the teeth. A 'clean tooth' model was used. No gingival or non-gingival lacerations or other signs of injury to oral tissues were found at the end of the 28 day trial period. Brushing more frequently had greater effectiveness in retarding accumulation of plaque and calculus, and reducing the severity of pre-existing gingivitis. Brushing daily or every other day produced statistically significant improved results compared with brushing weekly or every other week. Based on the results of this study, daily brushing is recommended.

  4. Higher Efficiency HVAC Motors

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Charles Joseph

    2018-02-13

    The objective of this project was to design and build a cost competitive, more efficient heating, ventilation, and air conditioning (HVAC) motor than what is currently available on the market. Though different potential motor architectures among QMP’s primary technology platforms were investigated and evaluated, including through the building of numerous prototypes, the project ultimately focused on scaling up QM Power, Inc.’s (QMP) Q-Sync permanent magnet synchronous motors from available sub-fractional horsepower (HP) sizes for commercial refrigeration fan applications to larger fractional horsepower sizes appropriate for HVAC applications, and to add multi-speed functionality. The more specific goal became the research, design, development, and testing of a prototype 1/2 HP Q-Sync motor that has at least two operating speeds and 87% peak efficiency compared to incumbent electronically commutated motors (EC or ECM, also known as brushless direct current (DC) motors), the heretofore highest efficiency HVACR fan motor solution, at approximately 82% peak efficiency. The resulting motor prototype built achieved these goals, hitting 90% efficiency and .95 power factor at full load and speed, and 80% efficiency and .7 power factor at half speed. Q-Sync, developed in part through a DOE SBIR grant (Award # DE-SC0006311), is a novel, patented motor technology that improves on electronically commutated permanent magnet motors through an advanced electronic circuit technology. It allows a motor to “sync” with the alternating current (AC) power flow. It does so by eliminating the constant, wasteful power conversions from AC to DC and back to AC through the synthetic creation of a new AC wave on the primary circuit board (PCB) by a process called pulse width modulation (PWM; aka electronic commutation) that is incessantly required to sustain motor operation in an EC permanent magnet motor. The Q-Sync circuit improves the power factor of the motor by removing all

  5. The Effects of a Brushing Procedure on Stereotypical Behavior

    Science.gov (United States)

    Davis, Tonya N.; Durand, Shannon; Chan, Jeffrey M.

    2011-01-01

    In this study we analyzed the effects of a brushing protocol on stereotyped behavior of a young boy with autism. First, a functional analysis was conducted which showed that the participant's stereotypy was maintained by automatic reinforcement. Next, the Wilbarger Protocol, a brushing intervention, was implemented. An ABA design was implemented…

  6. A Critique of the Brushing for Life Programme

    Science.gov (United States)

    Downer, Martin C.; Drugan, Caroline S.; Blinkhorn, Anthony S.

    2006-01-01

    Background and objective: Brushing for Life is intended to promote regular brushing of children's teeth with fluoride toothpaste. The programme is delivered by health visitors who provide toothbrushes, toothpaste and dental health education material at children's 8, 18 and 36 month development checks. The purpose of the present paper was to…

  7. Wildlife response to brush management: a contemporary evaluation

    Science.gov (United States)

    Brush management has been widely practiced with the general intent of curtailing or reversing the proliferation of shrubs and trees in grasslands and savannas. The traditional aim of brush management has been to increase livestock forage or to improve water yield. Its potential role for restoring h...

  8. Carbazole functionalized isocyanide brushes in heterojunction photovoltaic devices

    NARCIS (Netherlands)

    Lim, E.; Gao, F.; Schwartz, E.; Schwartz, E.; Cornelissen, Jeroen Johannes Lambertus Maria; Nolte, R.J.M.; Rowan, A.E.; Greenham, N.C.; Do, L.M.

    2012-01-01

    In this work, carbazole-containing polyisocyanide (PIACz) brushes were used for photovoltaic devices. A photovoltaic device was fabricated on top of the brushes by spin-coating a suitable acceptor and evaporating an Al cathode. Devices with a poly(N-vinylcarbazole) (PVK) bulk polymer were also

  9. Surface grafted polymer brushes: potential applications in dengue biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Baratela, Fernando Jose Costa; Higa, Olga Zazuco, E-mail: ozahiga@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Faria, Henrique Antonio Mendonca de; Queiroz, Alvaro Antonio Alencar de, E-mail: alencar@unifei.edu.br [Universidade Federal de Itajuba (UNIFEI), Itajuba, MG (Brazil). Instituto de Fisica e Quimica

    2013-07-01

    A polymer brush membrane-based ultrasensitive biosensor for dengue diagnosis was constructed using poly(hydroxyethyl methacrylate) (PHEMA) brushes immobilized onto low density polyethylene (LDPE) films. LDPE surface films were initially modified by Ar{sup +} ion irradiation to activate the polymer surface. Subsequently, graft polymerization of 2-hydroxyethyl methacrylate onto the activated LDPE surface was carried out under aqueous conditions to create patterned polymer brushes of PHEMA. The grafted PHEMA brushes were characterized by Fourier transform-infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis. The SEM observations showed that selective surface activation with Ar+ implantation and graft polymerization on the selectively activated surface had occurred. The PHEMA brushes were electrically characterized in the presence of concentrations of human immunoglobulin (IgG). The proposed amperometric biosensor was successfully used for determination of IgG in physiologic samples with excellent responses. (author)

  10. Polymer brushes on planar TiO2 substrates.

    Science.gov (United States)

    Yang, Jiming; Hou, Liman; Xu, Bin; Zhang, Ning; Liang, Yongjiu; Tian, Wenjing; Dong, Dewen

    2014-07-01

    A facile and universal method is presented for the preparation of polymer brushes on amorphous TiO2 film. Homogeneous and stable poly(methyl methacrylate), polystyrene, poly(4-vinylpyridine), and poly(N-vinyl imidazole) (PNVI) brushes up to 550 nm are directly created onto TiO2 via UV-induced photopolymerization of corresponding monomers. Kinetic studies reveal a linear increase in thickness with the polymerization time. Characterization of the resulting polymer brushes by FTIR spectroscopy, X-ray photoelectron spectroscopy, contact angle, and atomic force microscopy (AFM) indicates an efficient UV-grafting reaction. Finally, we have demonstrated the possibility in converting the PNVI brushes to poly(vinyl imidazolium bromide), i.e., poly(ionic liquid) brushes by polymer-analogous reactions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Tooth-brushing behaviour in 6-12 year olds.

    Science.gov (United States)

    Sandström, Anna; Cressey, Janet; Stecksén-Blicks, Christina

    2011-01-01

    A common clinical finding is that many schoolchildren display a nonacceptable oral hygiene. To evaluate the tooth-brushing behaviour in children aged 6-12 years. The study used a cross-sectional descriptive design. Children aged 6, 8, 10, and 12 years in an elementary school in a middle class area in Umeå, a city in northern Sweden, were invited and 82 (82%) consented. Visible plaque on buccal surfaces of incisors and canines was recorded from photographs of the participant's teeth before and after brushing using the scores of the Green and Vermillion Oral Hygiene Index. Brushing technique was recorded with a video camera. A questionnaire was used to collect data about oral hygiene habits at home. The ratio between the sum of plaque scores after and before brushing was statistically significantly higher in the 6-year-old group compared with the 10-year olds, (P brushing and the ratio between the sum of plaque scores after and before brushing (r = -0.31, P 0.05). Six-year olds spent statistically significantly less time for brushing than older children (P brushing was poor and averaged 19% for 6-year olds and 30% for older children. The results of brushing for children aged 8-12 years could benefit from increasing tooth-brushing time. Children could be given an increasing responsibility from 7 to 8 year of age but parental help is motivated up to 10 years of age. © 2010 The Authors. International Journal of Paediatric Dentistry © 2010 BSPD, IAPD and Blackwell Publishing Ltd.

  12. Three new DC-to-DC Single-Switch Converters

    Directory of Open Access Journals (Sweden)

    Barry W. Williams

    2017-06-01

    Full Text Available This paper presents a new family of three previously unidentified dc-to-dc converters, buck, boost, and buck-boost voltage-transfer-function topologies, which offer advantageous transformer coupling features and low capacitor dc voltage stressing. The three single-switch, single-diode, converters offer the same features as basic dc-to-dc converters, such as the buck function with continuous output current and the boost function with continuous input current. Converter time-domain simulations and experimental results (including transformer coupling support and extol the dc-to-dc converter concepts and analysis presented.

  13. Three new DC-to-DC Single-Switch Converters

    OpenAIRE

    Barry W. Williams; Mona Fouad Moussa

    2017-01-01

    This paper presents a new family of three previously unidentified dc-to-dc converters, buck, boost, and buck-boost voltage-transfer-function topologies, which offer advantageous transformer coupling features and low capacitor dc voltage stressing. The three single-switch, single-diode, converters offer the same features as basic dc-to-dc converters, such as the buck function with continuous output current and the boost function with continuous input current. Converter time-domain simulations ...

  14. Sensorless Control of Electric Motors with Kalman Filters: Applications to Robotic and Industrial Systems

    OpenAIRE

    Gerasimos G. Rigatos; Pierluigi Siano

    2011-01-01

    The paper studies sensorless control for DC and induction motors, using Kalman Filtering techniques. First the case of a DC motor is considered and Kalman Filter-based control is implemented. Next the nonlinear model of a field-oriented induction motor is examined and the motor's angular velocity is estimated by an Extended Kalman Filter which processes measurements of the rotor's angle. Sensorless control of the induction motor is again implemented through feedback of the estimated state vec...

  15. Comprehensive physical rehabilitation after injury brush

    Directory of Open Access Journals (Sweden)

    Kovalenko M.I.

    2012-08-01

    Full Text Available The influence of physical rehabilitation for patients after recovery efficiency injured hand. The study enrolled 36 patients after a hand injury, which was carried out surgery. Among patients were dominated women 66% and men 34% aged 25 to 50 years. To evaluate the effectiveness of rehabilitation programs used protractor Richter, centimeter tape, hand dynamometer, MHQ questionnaire and system of integral evaluation function brush. Survey of patients conducted at the clinical stage of rehabilitation for two weeks and before surgery. The efficiency effects of passive therapeutic exercises, massage and lymph drainage design for a hand operated device ARTROMOT-F. It is noted that physical rehabilitation for two weeks has greatly improved hand functions. Established to improve results core group of control by 21.8%, poor performance of the control group higher by 10.1% of the principal of, indicating the efficacy of the program.

  16. Macroion Interaction at Polyelectrolyte Brush Interfaces

    Science.gov (United States)

    Qu, Chen

    2015-03-01

    The effect of macroions, including synthetic polyelectrolytes, DNA and proteins, on the structure and surface properties of charged polymer thin films remains inadequately understood partially due to the complexity involving the hydrophobic effect and the conformational change of polymeric macroions. In this work, we explore a group of inorganic nanocluster based macroions, hydrophilic polyoxometalates (POMs) of robust nanocluster structure and carrying high surface charges (~ 2-42 negative charges) to investigate their interaction with surface tethered poly-2-vinylpyridine (P2VP) brush-like thin films immersed in aqueous solution. We observe the collapse of swollen P2VP chains by adding POM macroions of increased concentration by AFM, QCM and contact goniometer measurements, in sharp contrast to the increased chain stretching by adding monovalent salts. A careful comparison is made between distinct POMs based on their charge, size and chemical nature. These findings serve as a good reference for theoretical model modification and design of new mesoporous composite membranes.

  17. VALVE DIRECT CURRENT MOTOR ON THE BASIS OF THE SYNCHRONOUS MACHINE OF INVERSE DESIGN

    National Research Council Canada - National Science Library

    D. I. Morozov; I. S. Shevchenko

    2014-01-01

    .... It is shown that the switching frequency is determined by the armature rotation speed. Static mechanical characteristic of the rectifying DC machine is similar to that of the independent excitation of DC motor...

  18. VALVE DIRECT CURRENT MOTOR ON THE BASIS OF THE SYNCHRONOUS MACHINE OF INVERSE DESIGN

    Directory of Open Access Journals (Sweden)

    D. I. Morozov

    2014-12-01

    Full Text Available A mechanical collector of conventional DC machine is the element that limits the current and the armature speed and increases inertia. DC machine rectification realized on the basis of conventional DC machine is described; it externally rectifies the switch which is the analogue of the collector. The armature has a design similar to a phase-wound rotor of induction machine. It is shown that the switching frequency is determined by the armature rotation speed. Static mechanical characteristic of the rectifying DC machine is similar to that of the independent excitation of DC motor. The proposed variant of the DC motor is actually a synchronous machine of inverse design with armature regulation frequency. The motor is described as traditional salient pole synchronous machine. Starting dynamics simulation shows that the rectifying DC machine has better dynamic properties compared to the conventional DC motor due to overload capability and reduces the inertia of the armature

  19. Windshield wiper motor noise reduction; Jidoshayo waipa mota no soon teigen

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Y.; Ohashi, Y.; Ishikawa, M.; Teshirogi, I.; Sakakibara, M.; Aoki, K. [Jidosha Denki Kogyo Co. Ltd., Yokohama (Japan)

    1997-02-01

    Regarding automobile wipers, manual wipers were attached to a car in the beginning of 1916, pneumatic motor driven wipers were introduced in 1930, electric motor driven wipers appeared in 1950`s, and the existing style of wiper was perfected in 1957. The reduction of running noise of wiper motors in recent years has shown the most significant progress. In this article, the approaches towards reduction of running noise of wiper motors in recent years are described. First the basic structure of wiper motor is shown, then the sources of generation of vibration and the routes of its propagation are shown. The vibration from the direct current motor section consists of dynamic balance of rotor, vibration by fluctuation of magnetism, vibration due to the 3rd brush, brush noise, vibration from the reduction section and inversion noise. Their propagation routes are divided into radiation from the motor and propagation noise through body panels, and the respective evaluation methods are introduced. Concerning a method to reduce the running noise of motor, reduction of vibration of the direct current motor section (improvement of dynamic balance of rotor, reduction of vibrations by fluctuation of magnetism as well as the 3rd brush, and reduction of brush noise) and reduction of vibration from the reduction section are explained. 10 figs.

  20. 75 FR 68246 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-11-05

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F... to supersede an existing airworthiness directive (AD) that applies to all Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10- 10F, MD-10-30F, MD-11...

  1. 75 FR 20790 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-04-21

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F... (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F airplanes. This proposed AD would require...

  2. 75 FR 23571 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-05-04

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD...

  3. 75 FR 60602 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-10-01

    ... Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD...

  4. Three-port DC-DC converter with new integrated transformer for DC Distribution Systems

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Andersen, Michael A. E.

    2014-01-01

    A new integrated transformer for three-port dc-dc converter is proposed to overcome the power coupling effect existed in some known multiple inputs dc-dc converters. Orthogonal primary windings arrangement and in series connection of diagonal secondary Windings enables a fully power decoupling...

  5. A Robust Fuzzy Sliding Mode Controller Synthesis Applied on Boost DC-DC Converter Power Supply for Electric Vehicle Propulsion System

    Directory of Open Access Journals (Sweden)

    Boumediène Allaoua

    2013-01-01

    Full Text Available The development of electric vehicles power electronics system control comprising of DC-AC inverters and DC-DC converters takes a great interest of researchers in the modern industry. A DC-AC inverter supplies the high power electric vehicle motors torques of the propulsion system and utility loads, whereas a DC-DC converter supplies conventional low-power, low-voltage loads. However, the need for high power bidirectional DC-DC converters in future electric vehicles has led to the development of many new topologies of DC-DC converters. Nonlinear control of power converters is an active area of research in the fields of power electronics. This paper focuses on a fuzzy sliding mode strategy (FSMS as a control strategy for boost DC-DC converter power supply for electric vehicle. The proposed fuzzy controller specifies changes in the control signal based on the surface and the surface change knowledge to satisfy the sliding mode stability and attraction conditions. The performances of the proposed fuzzy sliding controller are compared to those obtained by a classical sliding mode controller. The satisfactory simulation results show the efficiency of the proposed control law which reduces the chattering phenomenon. Moreover, the obtained results prove the robustness of the proposed control law against variation of the load resistance and the input voltage of the studied converter.

  6. Rabbit antibodies reacting with brush border of rodent renal tubules

    Science.gov (United States)

    Ireton, H. J. C.; McGiven, A. R.

    1971-01-01

    The immunofluorescent staining characteristics of antibodies against rat and mouse kidney tubule brush border, produced in rabbits immunized with microsomal or mitochondrial fractions of rat kidney, were compared with those of human antibodies against mitochondria obtained from patients with biliary cirrhosis. With the rabbit antisera, brush border staining was confined to the epithelium of the proximal renal tubules while the human antimitochondrial sera stained proximal and distal tubules. Absorptions with a mitochondrial fraction prepared from rat liver inhibited the human serum activity but had no effect on brush border activity in the rabbit serum which was inhibited only by the rat kidney subcellular fractions. PMID:4931856

  7. SIMULATION MODELS OF HEAVY TRUCKS TRAFFIC CONTROL WITH ELECTRIC DC DRIVE

    Directory of Open Access Journals (Sweden)

    N. N. Hurski

    2015-01-01

    Full Text Available A model of the straight course of movement of the mobile machine with a traction electric motor DC. Traffic management controller provides a closed classical scheme with feedback. The mathematical model of the electric DC motor with the energy dissipation in the rotor bearings. Design scheme of mobile machines include speed dial controller, traction electric motor, gearbox, transmission and progressively moving mass on the elastic­dissipative wheel. The results of the simulation of the machine in the form of temporary processes of change control signals, voltage and current in the windings of the motor and traction power developed on the wheel.

  8. Adaptive Fuzzy Logic Controllers for DC Drives: A Survey of the State of the art

    Directory of Open Access Journals (Sweden)

    E. E. El-kholy

    2006-09-01

    Full Text Available Fuzzy Logic Control (FLC has gained a great demand in process control applications. Fuzzy Logic (FL technology enables the use of engineering experience and experimental results in designing an expert system capable of handling uncertain or fuzzy quantities. This paper presents a comprehensive review of FLC in the field of Direct Current (DC motor drive systems. Firstly, the principles of fuzzy logic theory will be briefly presented. Secondly, the employment of the FL techniques in a control system will be outlined. The concept of FLC can be extended for application to different DC motor drives such as: series, separately, shunt and permanent magnet DC motor. The limitations of FLC when applied to DC motor drives have been widely reported in the literature. This article also cites these limitations as well as the advancements in solving them through, for example, the genetic algorithms and the neural networks techniques.

  9. Overview of Multi-DC-Bus Solutions for DC Microgrids

    DEFF Research Database (Denmark)

    Ricchiuto, D.; Mastromauro, R.A.; Liserre, Marco

    2013-01-01

    DC Microgrids have recently received a lot of attention in the last years due to high penetration of renewable energy sources as well as distributed energy storage systems. In the future DC microgrids could be preferable respect to AC microgrids in terms of redundancy since multi-DC-Bus solutions...... could provide a continuative power supply to the loads. An overview of Multi-DC-Bus solutions is presented in this paper. The performances are compared on the basis of possible DC microgrid configurations, redundancy, different DC voltage levels....

  10. Brush Lettering II; Commercial and Advertising Art--Intermediate: 9185.01.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    This course outline has been prepared as a guide to help the student gain mastery in the proper brush techniques required for proficiency in brush lettering. The skills of Brush Lettering 1 are a prerequisite. Consisting of 135 clock hours, the course prepares the student to understand brush lettering for poster production and advertising layout.…

  11. Antimicrobial penetration in a dual-species oral biofilm after noncontact brushing : an in vitro study

    NARCIS (Netherlands)

    He, Y.; Peterson, B. W.; Ren, Y.; van der Mei, H. C.; Busscher, H. J.

    Oral biofilm is inevitably left behind, even after powered brushing. As a special feature, powered brushing removes biofilm in a noncontact mode. When the brushing distance becomes too large, biofilm is left behind. We hypothesize that biofilm left behind after brushing has different viscoelastic

  12. On the collapse transition of a polymer brush: the case of lateral mobility

    NARCIS (Netherlands)

    Leermakers, F.A.M.; Egorov, S.A.

    2013-01-01

    We consider a polymer brush composed of end-grafted polymer chains. Classical theory advocates that a worsening of the solvent quality results in a smooth decrease of the brush height from a swollen to a dense brush. We report that a homogeneous brush under poor solvent conditions can have a

  13. Power factor correction (PFC) converters feeding brushless DC ...

    African Journals Online (AJOL)

    This paper presents a comprehensive study of power factor correction (PFC) converters for feeding brushless DC (BLDC) motor drive. This work explores various configurations of PFC converters which are classified into five different categories of non-isolated, bridgeless (BL) non-isolated, isolated, BL-isolated PFC ...

  14. Electroosmotic Flow in Mixed Polymer Brush-Grafted Nanochannels

    Directory of Open Access Journals (Sweden)

    Qianqian Cao

    2016-12-01

    Full Text Available Mixed polymer brush-grafted nanochannels—where two distinct species of polymers are alternately grafted on the inner surface of nanochannels—are an interesting class of nanostructured hybrid materials. By using a coarse-grained molecular dynamics simulation method, we are able to simulate the electrokinetic transport dynamics of the fluid in such nanochannels as well as the conformational behaviors of the mixed polymer brush. We find that (1 the brush adopts vertically-layered and longitudinally-separated structures due to the coupling of electroosmotic flow (EOF and applied electric field; (2 the solvent quality affects the brush conformations and the transport properties of the EOF; (3 the EOF flux non-monotonically depends on the grafting density, although the EOF velocity in the central region of the channel monotonically depends on the grafting density.

  15. Superhydrophilic Polyelectrolyte Brush Layers with Imparted Anti-Icing Properties

    DEFF Research Database (Denmark)

    Chernyy, Sergey; Järn, Mikael; Shimizu, Kyoko

    2014-01-01

    (-), SO4(2-), and C12SO3(-) ions. By consecutive measurements of the strength of ice adhesion toward ion-incorporated polymer brushes on glass it was found that Li(+) ions reduce ice adhesion by 40% at -18 °C and 70% at -10 °C. Ag(+) ions reduce ice adhesion by 80% at -10 °C relative to unmodified glass......This work demonstrates the feasibility of superhydrophilic polyelectrolyte brush coatings for anti-icing applications. Five different types of ionic and nonionic polymer brush coatings of 25-100 nm thickness were formed on glass substrates using silane chemistry for surface premodification followed...... by polymerization via the SI-ATRP route. The cationic [2-(methacryloyloxy)ethyl]trimethylammonium chloride] and the anionic [poly(3-sulfopropyl methacrylate), poly(sodium methacrylate)] polyelectrolyte brushes were further exchanged with H(+), Li(+), Na(+), K(+), Ag(+), Ca(2+), La(3+), C16N(+), F(-), Cl(-), BF4...

  16. 75 FR 18237 - Natural Bristle Paint Brushes From China

    Science.gov (United States)

    2010-04-09

    ... paint brushes from China would be likely to lead to ] continuation or recurrence of material injury... information on this matter by contacting the Commission's TDD terminal on 202-205- 1810. Persons with mobility...

  17. Anthrax in Vintage Animal-hair Shaving Brushes

    Centers for Disease Control (CDC) Podcasts

    2017-08-08

    Dr. Kate Hendricks, a CDC anthrax expert, discusses anthrax in vintage shaving brushes.  Created: 8/8/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/8/2017.

  18. Astronauts Culbertson and Bursch brush their teeth on Discovery's middeck

    Science.gov (United States)

    1993-01-01

    Astronauts Frank L. Culbertson (right), mission commander, and Daniel W. Bursch, mission specialist, brush their teeth on Discovery's middeck. Two sleep restraints form part of the backdrop for the photograph.

  19. The study of functional parameter of the electric coal brushes

    Directory of Open Access Journals (Sweden)

    Claudia Staşac

    2008-05-01

    Full Text Available These paper present a study about the analyzeof the functional parameters of the electrical coal brush.The analyze was made with an experimental device, andthe results was prelucrate in MathCAD software.

  20. Influence of Geometry on Rotordynamic Coefficients of Brush Seal

    Science.gov (United States)

    Wei, Yuan; Dowell, Earl H.; Chen, Zhaobo; Jiao, Yinghou; Zhang, Zhouqiang

    2017-05-01

    It has been observed that the geometry of a brush seal has a significant effect on the sealing performance. However, the relationship between rotordynamic coefficients and geometry factors of the brush seal itself are rarely considered. In this article, the rotordynamic coefficients of a typical single-stage brush seal for different geometries and operating conditions were numerically analyzed using CFD RANS solutions coupled with a non-Darcian porous medium model. The reaction force which plays an essential role in rotordynamic coefficients was obtained by integrating the dynamic pressure distribution. The influence of the bristle pack thickness, fence height, clearance size and other working condition parameters on aerodynamic force, stiffness coefficients, and damping coefficients of brush seal were presented and compared. In addition, the effects of various geometric configurations on pressure and flow features were also discussed.

  1. Polyelectrolyte complexes of bottle brush copolymers : Solution and adsorption properties

    OpenAIRE

    Alexander, Shovsky

    2011-01-01

    The aim of this thesis work was to systematically investigate the physico-chemical properties of polyelectrolyte complexes (PECs) formed by bottle brush and linear polyelectrolytes in solution and at solid / liquid interfaces. Electrostatic self-assembly of oppositely charged macromolecules in aqueous solution is a versatile strategy to construction of functional nanostructures with easily controlled properties. Bottle brush architecture, introduced into the PEC, generates a number of distinc...

  2. DC arc weld starter

    Science.gov (United States)

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  3. Advanced AC Motor Control

    Energy Technology Data Exchange (ETDEWEB)

    Kazmierkowski, M.P. [Institute of Control and Industrial Electronics, Warsaw University of Technology, Warszawa (Poland)

    1997-12-31

    In this paper a review of control methods for high performance PWM inverter-fed induction motor drives is presented. Starting from the description of an induction motor by the help of the space vectors, three basic control strategic are discussed. As first, the most popular Field Oriented Control (FOC) is described. Secondly, the Direct Torque and Flux vector Control (DTFC) method, which - in contrast to FOC - depart from idea of coordinate transformation and analogy with DC motor, is briefly characterized. The last group is based on Feedback Linearization Control (FLC) and can be easy combined with sliding mode control. The simulation and experimental oscillograms that illustrate the performance of the discussed control strategies are shown. (orig.) 35 refs.

  4. Motor Neurons

    DEFF Research Database (Denmark)

    Hounsgaard, Jorn

    2017-01-01

    Motor neurons translate synaptic input from widely distributed premotor networks into patterns of action potentials that orchestrate motor unit force and motor behavior. Intercalated between the CNS and muscles, motor neurons add to and adjust the final motor command. The identity and functional...

  5. Cues to Action as Motivators for Children's Brushing.

    Science.gov (United States)

    Walker, Kimberly K; Steinfort, Erin L; Keyler, Maria J

    2015-01-01

    Dental caries is the most common chronic childhood disease. Home self-care procedures are the most important strategies to prevent tooth decay. Brushing is the most important single intervention for the prevention of tooth decay, yet compliance is not practiced and there is limited understanding of children's behavioral decisions. Guided by the Health Belief Model, this study consisted of eight focus groups with children in the second through fifth grades at three different socioeconomic-level school districts to determine the cues to action that are motivating or can motivate their brushing behavior. Results indicated children are primarily motivated to brush for aesthetic reasons, mainly due to viewed media pictures of "perfect" teeth. Other less commonly expressed motivations for brushing stemmed from interpersonal connections, such as relatives with dentures. Social media, on the other hand, played a key role in some children's understanding of more advanced oral health connections such as links between cardiovascular and oral disease, and smoking and oral cancer. These links were viewed as threatening to children to motivate better brushing. Additionally, the study found that home computers can be used as an external motivator to deliver tailored messages to encourage better brushing.

  6. The Unusual Conformational Behavior of Polyzwitterionic Brushes in Aqueous Solutions

    Science.gov (United States)

    Mao, Jun; Chen, Wei; Yuan, Guangcui; Yu, Jing; Tirrell, Matthew

    Polyzwitterions constitute a peculiar class of polyelectrolytes, which are electrically neutral polymers containing both a positive and a negative charge on each repeating unit. Surfaces coated with polyzwitterionic brushes are resistant to the nonspecific accumulation of proteins and microorganisms, making them excellent candidates for a wide range of antifouling applications, from biocompatible medical devices to marine coatings. The surrounding environment can dramatically influence the conformational behavior of polyzwitterionic brushes. High-density polyzwitterionic brushes poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) were synthesized using surface initiated atom-transfer radical polymerization, and neutron reflectivity (NR) measurements were performed to investigate the ionic strength dependence of the conformational behaviors of PMPC brushes in monovalent salt solutions. Despite the numerous observations of normal pure polyelectrolyte brushes, NR results showed that both the densely concentrated layer near the substrate surface and the relatively swollen layer into the solution have been observed in different q range in a single neutron reflectivity profile. These results will definitely help us to better understand the relationship between the solution behaviors of zwitterionic polymer brushes and their antifouling properties.

  7. Electrical Resistivity Tomography Reveals Upward Redistribution of Soil-Water by Coyote Brush in a Shrub-Grassland Ecotone

    Science.gov (United States)

    Manning, J. E.; Schulz, M. S.; Lambrecht, D. S.

    2016-12-01

    Species imbalance within many California plant assemblages may arise due to more intense wildfires as well as climate warming. Given this, coyote brush (Baccharis pilularis DC), a native evergreen shrub known as a ready colonizer of disturbed soil, may become more dominant. While prolonged spring soil moisture is required for seedling establishment, 1+ year-old coyote brush can withstand low soil water potentials (-1.2 MPa). Beyond this, little is known about its soil-water dynamics. Hydraulic redistribution of water within the soil profile by plant roots has been established in numerous species in the past 20 years. Recent quantification of the water quantity re-distributed by root systems are beginning to provide detail that could inform ET, weathering, and carbon cycling models. Electrical resistivity tomography (ERT) has been used to study soil hydraulics in natural as well as cropland settings. This study is the first known to use ERT to investigate hydraulic redistribution in coyote brush. One mid-size shrub surrounded by open grassland was selected at the study site, located on a coastal marine terrace west of Santa Cruz, CA. The soil profile, previously characterized with ERT and auger-based soil-water sampling, includes a clay-rich B horizon and is texturally non-uniform due to bioturbation to 0.6 meter. The 12-m ERT survey transect had 48 semi-permanent electrodes, with the 4-m wide shrub canopy at probes 16 to 32. Five repeats of evening and morning surveys were conducted. Heterogeneous texture and severe soil drying necessitated qualitative comparison across time. Overnight resistivity changes using differences plots of the modelled data revealed increased moisture beneath the shrub canopy during the night. Areas beyond the canopy—presumably outside the root zone—experienced variable overnight changes, with moisture increasing in the clay-rich horizon. Preliminary analysis suggests that coyote brush roots redistribute water upward within the soil

  8. Fuel pump with brushless motor for high vibration applications; Kraftstoffpumpe mit buerstenlosen Motor fuer Anwendungen mit starken Vibrationen

    Energy Technology Data Exchange (ETDEWEB)

    Muenchow, Frank [Federal-Mogul, Bad Camberg (Germany). Geschaeftsbereich Vehicle Safety and Protection; Harvey, Richard; Richards, Michael [Federal-Mogul Corporation, Logansport, IN (United States). Business Unit Vehicle Safety and Protection

    2012-03-15

    Electrifying components in commercial vehicles can be a challenge. High vibration levels, for instance, amplify carbon brush and commutator erosion in a conventional electric motor. To offer a solution Federal-Mogul has developed the brushless fuel pump. This BLDC pump has successfully passed 10,000 h of operation in B100 fuel. (orig.)

  9. What is the best predictor for oral cleanliness after brushing? Results from an observational cohort study.

    Science.gov (United States)

    Harnacke, Daniela; Winterfeld, Tobias; Erhardt, Jörg; Schlueter, Nadine; Ganss, Carolina; Margraf-Stiksrud, Jutta; Deinzer, Renate

    2015-01-01

    Brushing performance is an important factor for brushing success. Thus, observing brushing performance might help to explain deficits in oral hygiene. However, it is unknown how brushing behavior observed at one time relates to brushing capabilities observed at another time. The authors assessed the predictive validity of video-observed habitual brushing behavior for the capability to achieve oral cleanliness several weeks later. Study participants (N = 101) were video-recorded while cleaning their teeth. Two independent, calibrated examiners assessed brushing duration, evenness of distribution of brushing time across areas of the mouth as one indicator of brushing systematics, and duration of specific brushing movements. Weeks later (mean: 6.4 weeks; range: 1 to 24 weeks), 70 participants were asked to remove plaque to the best of their ability, and degree of oral cleanliness was assessed immediately afterward. A forward regression analysis was performed to assess the predictive values of brushing parameters. Regression analysis revealed that evenness of distribution of brushing time and duration of circling movements explained 20.8% of variance of oral cleanliness (P brushing time and duration of circling movements are aspects of observed habitual brushing behavior that predict brushing capabilities in terms of oral cleanliness.

  10. Early Oscillation Detection for DC/DC Converter Fault Diagnosis

    Science.gov (United States)

    Wang, Bright L.

    2011-01-01

    The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

  11. Efficiency Measurement Using a Motor-Dynamo Module

    Science.gov (United States)

    Ng, Pun-hon; Wong, Siu-ling; Mak, Se-yuen

    2009-01-01

    In this article, we describe a simple method which can be used to measure the efficiency of a low power dc motor, a motor-converted dynamo and a coupled motor-dynamo module as a function of the speed of rotation. The result can also be used to verify Faraday's law of electromagnetic induction. (Contains 1 table and 8 figures.)

  12. 75 FR 6160 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, DC-10-15, DC...

    Science.gov (United States)

    2010-02-08

    ... Douglas Corporation Model DC- 10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F Airplanes AGENCY: Federal Aviation... airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC- 10A and...

  13. Design of a kilowatt DC-DC converter

    Directory of Open Access Journals (Sweden)

    Liu Hongxing

    2017-01-01

    Full Text Available In view of the low power of traditional DC-DC converters, a DC-DC converter with a kilowatt power is designed. The input signal's frequency is 1 kHz and the duty cycle is 5%. The PWM signal controls the high-speed conduction or cut-off of the switch tube. The input DC voltage is 36V, and the output voltage is twice as high as the input voltage. The output power is greater than 1 KW; the circuit conversion efficiency is 87.21%.

  14. The Secretion and Action of Brush Border Enzymes in the Mammalian Small Intestine.

    Science.gov (United States)

    Hooton, Diane; Lentle, Roger; Monro, John; Wickham, Martin; Simpson, Robert

    2015-01-01

    Microvilli are conventionally regarded as an extension of the small intestinal absorptive surface, but they are also, as latterly discovered, a launching pad for brush border digestive enzymes. Recent work has demonstrated that motor elements of the microvillus cytoskeleton operate to displace the apical membrane toward the apex of the microvillus, where it vesiculates and is shed into the periapical space. Catalytically active brush border digestive enzymes remain incorporated within the membranes of these vesicles, which shifts the site of BB digestion from the surface of the enterocyte to the periapical space. This process enables nutrient hydrolysis to occur adjacent to the membrane in a pre-absorptive step. The characterization of BB digestive enzymes is influenced by the way in which these enzymes are anchored to the apical membranes of microvilli, their subsequent shedding in membrane vesicles, and their differing susceptibilities to cleavage from the component membranes. In addition, the presence of active intracellular components of these enzymes complicates their quantitative assay and the elucidation of their dynamics. This review summarizes the ontogeny and regulation of BB digestive enzymes and what is known of their kinetics and their action in the peripheral and axial regions of the small intestinal lumen.

  15. DC micro-grids

    OpenAIRE

    Mia, Gredelj

    2014-01-01

    The conventional electrical system in place today sees our electrical devices powered by AC mains. But as renewable technologies such as solar photovoltaic and wind power become more prevalent at a household level, DC micro-grids could be a cheaper and more efficient alternative. New lighting devices (LED) can reduce the electricity consumption substantially. Two alternatives are envisioned in this paper: A stand-alone alternative in which there is no grid connection, that would require local...

  16. Manipulating protein adsorption using a patchy protein-resistant brush.

    Science.gov (United States)

    Gon, Saugata; Bendersky, Marina; Ross, Jennifer L; Santore, Maria M

    2010-07-20

    Toward the development of surfaces for the precise manipulation of proteins, this study explores the fabrication and protein-interactive behavior of a new type of surface containing extremely small (on the order of 10 nm or less) flat adhesive "patches" or islands embedded in and partially concealed by a protein-repellant PEG (poly(ethylene glycol)) brush. The adsorption of fibrinogen, the model protein chosen to probe the biomaterial interactions of these surfaces, is very sensitive to the surface density of the adhesive patches, occurring only above a threshold. This suggests that two or more adhesive patches are needed to capture each protein. When the average spacing of the adhesive patches exceeds the fibrinogen length, no adsorption occurs because individual patches are too weakly binding for protein capture, as a result of being at least partially obstructed by the brush. The small size of the adhesive patches relative to the 47 nm fibrinogen length thus defines a limiting regime of surface design, distinct from surfaces where larger features can adhere single isolated proteins or multiple proteins together. The restricted protein-surface contact may comprise a means of preserving protein structure and function in the adsorbed state. This article demonstrates several additional interesting features of PEG brushes relevant to biomaterial design. First a moderate amount of adhesive material can be buried at the base of a brush without a measurable impact on the corona density. Second, a different amount of material at the base of a brush can be rendered ineffective to capturing adhesive proteins, despite a modest compromise of the brush corona. From this will follow insight into the design of patterned biomaterial surfaces, the bioactivity of the edges of patterned features, and an understanding of how flaws in brushes compromise protein resistance or allow access to small adhesive sites.

  17. Comparison of the kinetic friction of planar neutral and polyelectrolyte polymer brushes using molecular dynamics simulations.

    Science.gov (United States)

    Ou, Yangpeng; Sokoloff, Jeffrey B; Stevens, Mark J

    2012-01-01

    We have simulated the relative shear motion of both neutral and polyelectrolyte end-grafted polymer brushes using molecular dynamics. The flexible neutral polymer brush is treated as a bead-spring model, and the polyelectrolyte brush is treated the same way except that each bead is charged and there are counterions present to neutralize the charge. We investigated the friction coefficient, monomer density, and brush penetration for both polyelectrolyte and neutral brushes with both equal grafting density and equal normal force under good solvent conditions. We found that polyelectrolyte brushes had a smaller friction coefficient and monomer penetration than neutral polymer brushes with the identical grafting density and chain length, and the polyelectrolyte brushes supported a much higher normal load than the neutral brushes for the same degree of compression. Charged and neutral brushes with their grafting densities chosen so that they support the same load exhibited approximately the same degree of interpenetration, but the polyelectrolyte brush exhibited a significantly lower friction coefficient. We present evidence that the reason for this is that the extra normal force contribution provided by the counterion osmotic pressure that exists for polyelectrolyte brushes permits them to support the same load as an identical neutral polymer brush of higher grafting density. Because of the resulting lower monomer density for the charged brushes, fewer monomer collisions take place per unit time, resulting in a lower friction coefficient. © 2012 American Physical Society

  18. Robust method for stator current reconstruction from DC link in a ...

    African Journals Online (AJOL)

    ... induction motor drive, using a dSPACE 1104 controller board is presented to validate the proposed algorithm. Keywords: Algorithm, current-reconstruction, current-sensor, dc-link, hysteresis modulation, three-phase induction motor. International Journal of Engineering, Science and Technology, Vol. 2, No. 10, 2010, pp.

  19. The influence of tooth brushing time over saliva buffering capacity

    Directory of Open Access Journals (Sweden)

    Sri Mulyanti

    2014-11-01

    Full Text Available Saliva gives a considerable influence against the growth of dental caries as a natural defense against caries. the things very important about saliva are its flow rate and buffering capacity. the decrease in saliva flow rate might cause food retention that furthermore would turn into dental plaques, meanwhile it’s buffering capacity will play a considerable role in maintaining the saliva’s pH and remineralization process of the teeth. One of the mechanisms which are considered to be effective in preventing dental caries is teeth brushing which could change the pH of 5,6 to a normal level. And the right time of teeth brushing will provide an optimal result.The study aims to reveal the influence of teeth brushing time against saliva buffering capacity. The study is an analytic study using a quasi-experimental design. The samples of the study are 20 (twenty students of dentistry in Health Ministry of Bandung which was purposively selected the sample is divided into 3 groups. The first group is treated by brushing their teeth right after eating bread, the second and third group is treated 15 and 30 minutes after eating bread. The hypothesis uses Kruskal Wallis hypothesis continued by Mann Whitney test, strikethrough. The study reveals that the group brushed their teeth right after eating bread shows low category of saliva buffering is that 55% meanwhile those who brushed their teeth 15 and 30 minutes after eating bread exhibits the result as much as 65% and 25 % Thus the last group is included to those who have a medium risk of suffering from dental carries. The statistics of Kruskal Wallis test within the confidence level of 95% shows that there is an influence of teeth brushing time over the saliva buffering capacity with p<0,001. Mann Whitney test shows that the time of teeth brushing within 15 minutes after eating is better than the group who brush their teeth 30 minutes after eating.

  20. Dynamic Evolution Control for Fuel Cell DC-DC Converter

    Directory of Open Access Journals (Sweden)

    Ahmad Saudi Samosir

    2011-04-01

    Full Text Available Fuel cells are new alternative energy resource that has a great promise for distributed generation and electric vehicle application. However, fuel cells have a slow response due to their slow internal electromechanical and thermodynamic response. To optimize the fuel cell system performance, a fuel cell DC-DC converter with an appropriate controller which can regulate the power flow and automatically adjust the converter output voltage is needed. This paper proposes a new control technique for fuel cell DC-DC power converter. Design of the proposed control method for fuel cell DC-DC power converter is provided. A new approach for converter controllers synthesis based on dynamic evolution control theory is presented. In this paper, synthesis example of boost DC-DC converter is discussed. Performance of the proposed dynamic evolution control under step load variation condition is simulated under Matlab-Simulink environment. Simulation results show that the proposed techniques are capable for controlling fuel cell DC-DC converter.

  1. Endobiliary brush biopsy: Intra- and interobserver variation in cytological evaluation of brushings from bile duct strictures

    DEFF Research Database (Denmark)

    Adamsen, S; Olsen, M; Jendresen, MB

    2006-01-01

    OBJECTIVE: Obtaining cytological specimens by wire-guided endobiliary brushing at the time of endoscopic retrograde cholangiopancreatography (ERCP) is a convenient way to reach a diagnosis. Sensitivity for malignant disease is generally around 50% and specificity around 100%. The present study...... was designed to assess the reproducibility of the cytological examination. MATERIAL AND METHODS: Samples were obtained from 55 consecutive patients with biliary duct strictures that eventually turned out to be caused by malignant disease in 41 patients (73%). The cytology specimens were evaluated twice...... in different random order with an interval of at least 4 months by two pathologists blinded to the final diagnoses. Suitability for diagnosis (suitable, suboptimal or unsuitable) and cytologic diagnosis (benign, atypical, suspicious for malignancy and malignant cells) were registered. Kappa analysis...

  2. A new optimum topology switching dc-to-dc converter

    Science.gov (United States)

    Cuk, S.; Middlebrook, R. D.

    1977-01-01

    A novel switching dc-to-dc converter is presented, which has the same general conversion property (increase or decrease of the input dc voltage) as does the conventional buck-boost converter, and which offers through its new optimum topology higher efficiency, lower output voltage ripple, reduced EMI, smaller size and weight, and excellent dynamic response. One of its most significant advantages is that both input and output current are not pulsating but are continuous (essentially dc with small superimposed switching current ripple), thus resulting in a close approximation to the ideal physically nonrealizable dc-to-dc transformer. The converter retains the simplest possible structure with the minimum number of components which, when interconnected in its optimum topology, yield the maximum performance.

  3. A new tribological test for candidate brush seal materials evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Fellenstein, J.A. [Ohio Aerospace Inst. Cleveland, Ohio (United States); DellaCorte, C. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center

    1994-10-01

    A new tribological test for candidate brush seal materials evaluation has been developed. The sliding contact between the brush seal wires and their mating counterface journal is simulated by testing a small tuft of wire against the outside diameter of a high speed rotating shaft. The test configuration is similar to a standard block on ring geometry. The new tester provides the capability to measure both the friction and wear of candidate wire and counterface materials under controlled loading conditions in the gram to kilogram range. A wide test condition latitude of speeds (1 to 27 m/s), temperatures (25 to 700C), and loads (0.5 to 10 N) enables the simulation of many of the important tribological parameters found in turbine engine brush seals. This paper describes the new test rig and specimen configuration and presents initial data for candidate seal materials comparing tuft test results and wear surface morphology to field tested seal components.

  4. Surface Modification of Nonwoven fabrics by Atmospheric Brush Plasma

    Science.gov (United States)

    Oksuz, Lutfi; Uygun, Emre; Bozduman, Ferhat; Yurdabak Karaca, Gozde; Asan, Orkun Nuri; Uygun Oksuz, Aysegul

    2017-10-01

    Polypropylene nonwoven fabrics (PPNF) are used in disposable absorbent articles, such as diapers, feminine care products, wipes. PPNF need to be wettable by water or aqueous-based liquid. Plasma surface treatment/modification has turned out to be a well-accepted method since it offers superior surface property enhancement than other chemical methods. The cold plasma brush can most efficiently use the discharge power as well as the plasma gas for material and surface treatment. The very low power consumption of such an atmospheric argon plasma brush provides many unique advantages in practical application. The purpose of this study was to reveal the effectiveness of non-thermal atmospheric plasma brush in surface wettability and modification of two different nonwoven surfaces.

  5. Surface changes of enamel after brushing with charcoal toothpaste

    Science.gov (United States)

    Pertiwi, U. I.; Eriwati, Y. K.; Irawan, B.

    2017-08-01

    The aim of this study was to determine the surface roughness changes of tooth enamel after brushing with charcoal toothpaste. Thirty specimens were brushed using distilled water (the first group), Strong® Formula toothpaste (the second group), and Charcoal® Formula toothpaste for four minutes and 40 seconds (equivalent to one month) and for 14 minutes (equivalent to three months) using a soft fleece toothbrush with a mass of 150 gr. The roughness was measured using a surface roughness tester, and the results were tested with repeated ANOVA test and one-way ANOVA. The value of the surface roughness of tooth enamel was significantly different (p<0.05) after brushing for an equivalent of one month and an equivalent of three months. Using toothpaste containing charcoal can increase the surface roughness of tooth enamel.

  6. Polyacrylic acid polymer brushes as substrates for the incorporation of anthraquinone derivatives. Unprecedented application of decorated polymer brushes on organocatalysis

    Science.gov (United States)

    Ruiz-Muelle, Ana Belén; Contreras-Cáceres, Rafael; Oña-Burgos, Pascual; Rodríguez-Dieguez, Antonio; López-Romero, Juan Manuel; Fernández, Ignacio

    2018-01-01

    The synthesis of amino-terminated anthraquinone derivatives and their incorporation onto polymer brushes for the fabrication of silicon-based nanometric functional coatings are described for the first time. The general process involves the covalent grafting of anthraquinone 1 onto two different polymer-brushes by amidation reactions. They are composed by amino- and carboxy-terminated poly(acrylic acid) chains (PAA-NH2- and PAA-COOH, respectively) tethered by one end to an underlying silicon oxide (SiO2) substrate in a polymer brush configuration. A third substrate is fabricated by UV induced hydrosilylation reaction using undecenoic acid as adsorbate on hydrogen-terminated Si(111) surfaces. One- and two-dimensional nuclear magnetic resonance (NMR), FT-IR, MS and X-ray diffraction (XRD) were used to characterize anthraquinone 1. Ellipsometric and X-ray photoelectron spectroscopy (XPS) measurements demonstrated the presence of the polymer brushes on the silicon wafers, and atomic force microscopy (AFM) was used to study its surface morphology. The covalent linkage between anthraquinone and polymer brushes was proven by XPS and confocal fluorescence microscopy. The resulting surfaces were assayed in the heterogenous organocatalytic transformation of (1H)-indole into 3-benzyl indole with moderate yields but with high recyclability.

  7. Scientific Laboratory Platform for Testing the Electric Vehicle Equipped with DC Drive

    Directory of Open Access Journals (Sweden)

    Brazis V.

    2014-12-01

    Full Text Available The authors present a test platform for the low-power DC electric motor of a traction vehicle or a high-power motor scaled in the traction and braking modes. The load emulator of the traction drive is made using an induction motor controlled by a frequency converter. A microcontroller controls the bi-directional DC/DC converter and sends a speed reference signal to the frequency converter. The test bench is meant for determination of the power consumption by motor in various speed cycles, and will be used to demonstrate the operation of electric vehicle to students and to investigate the charging/discharging strategies of energy sources.

  8. PENGGUNAAN FUZZY LOGIC UNTUK KONTROL PARALLEL CONVERTER DC-DC

    Directory of Open Access Journals (Sweden)

    Bambang Prio Hartono

    2012-09-01

    Full Text Available Abstract: Using system fuzzy logic as control  technology have been used on low load dc-dc converter with combined parallel compiled  dc-dc converter can  obtain big load.   With existence of differrence of component parameter and each parallel compiled converter can obtained different current  and voltage output.  Function of controller  for to do adjustment, so that current which is applied  to  load by each converter  can be obtained  difference error as small as possible or same. The object of research is developing design of large signal dc-dc converter which is  combined with using  FLC so that  obtain  better performance.  To get better performance have been made plant model and simulation with CDE method.  The more systematic  system and design is needed to overcome bigger load  on dc-dc converter, so that parallel  compiled current master slave control system on dc-dc converter with using fuzzy logic  controller is used. Result of  research showed that error or difference of  current  which is applied to load can handled by fuzzy logic  controller.  Technic of current and voltage controller co to do adjustment current and voltage distribution  equally to load.  Distribution of iL1,iL2 and  output voltage Vo on dc-dc  converter with load 2,25 until  7,875 and voltage  100  until 120 volt,  load current beetwen  12 until 48, % relatif  error  Vo  0,4% until  0,9%.

  9. Insulation Coordination and Failure Mitigation Concerns for Roust Dc Electrical Power Systems (Preprint)

    Science.gov (United States)

    2014-05-01

    create light, powerful and controllable motors through dc brushless technology. Unfortunately, some complications are created by the presence of high...have been developed to qualify random-wound induction motors for use with pulse-width-modulated drives to control motor speed and/or torque. This...Systems (Type I) Used in Rotating Electrical Machines Fed From Voltage Converters—Qualification and Quality Control Tests, International Standard

  10. Direct Sensitivity Analysis of the DC-to-DC Converters

    Directory of Open Access Journals (Sweden)

    Elena Niculescu

    2009-05-01

    Full Text Available The mathematical principle of the directsensitivity analysis of the dynamic systems and itsapplication to the DC-to-DC PWM converters arepresented. The model of the dynamic system associatedto the PWM Sepic converter with parasitic includedand continuous conduction mode (CCM, and coupledinductors was used in this study. The modelling of theconverter and the state sensitivity analysis with respectto some parameters of the converter have beenperformed with MATLAB environment. The algorithmcarried out for computing the state sensitivity functionsof converter can be applied to other configurations ofDC-to-DC PWM converters, for the two operatingmodes (CCM and DCM, with parasitic included andwith coupled or separate inductors, regardless ofsystem order.

  11. A.c. commutator motors. Part II. Three-phase shunt motors; Wechselstrom-Kommutatormotoren. Teil II. Drehstrom-Nebenschlussmotoren

    Energy Technology Data Exchange (ETDEWEB)

    Kunze, G.

    2002-04-01

    Three-phase commutator motors are speed-controlled motors which have been used for many years in application where exact electronic contro is not required, although they are more complex than d.c. shunt motors. [German] Als drehzahlsteuerbarer Motor hat sich insbesondere in Anwendungen, bei denen es nicht auf exakte elektronische Steuerung ankommt, ueber viele Jahre hinweg auch der Drehstrom-Kommutatormotor einen Namen gemacht. Dessen Innenleben ist allerdings komplizierter als das des vergleichbaren Gleichstrom-Nebenschlussmotors. (orig.)

  12. Why Iranian adolescents do not brush their teeth: a qualitative study.

    Science.gov (United States)

    Pakpour, A H; Hidarnia, A; Hajizadeh, E; Kumar, S; Fridlund, B

    2012-05-01

    To explore and describe attitudes towards tooth-brushing among Iranian adolescents. A series of focus-group sessions were held with 37 Iranian adolescents in schools. The groups comprised five to eight adolescents. All focus-group discussions were tape-recorded and then transcribed verbatim. All transcripts, codes and categories were read several times to extract a theme. Data were analysed using a qualitative content analysis approach. Four major categories emerged from the analysis: brushing teeth is a necessary evil, parental influence on not brushing teeth, brushing teeth is insignificant, and brushing teeth is a health hazard. The theme identified in the latent content described that tooth-brushing is not part of the adolescents' activities of daily living. Health educators should stress on the engagement of parents, awareness of the adolescents on brushing techniques and causes of toothache, and address any misconceptions regarding tooth-brushing. © 2011 John Wiley & Sons A/S.

  13. Fiabilidad de un motor de corriente continua

    OpenAIRE

    Flotats Villagrasa, Carles

    2009-01-01

    El objetivo del proyecto “Fiabilidad de un motor de corriente continua” consiste en estudiar los modos de fallo de un motor DC empleado en un automatismo para poder determinar idóneamente el mantenimiento preventivo; en encontrar recomendaciones de uso y diseño para reducir la severidad de los fallos y en desarrollar soluciones para aquellos modos de difícil cuantificación. Como pasos previos, se da una introducción al producto que usará el motor y al motor en si mismo, a los modos de uso ...

  14. Effect of a non-thermal, atmospheric-pressure, plasma brush on conversion of model self-etch adhesive formulations compared to conventional photo-polymerization

    Science.gov (United States)

    Chen, Mingsheng; Zhang, Ying; Yao, Xiaomei; Li, Hao; Yu, Qingsong; Wang, Yong

    2012-01-01

    Objective To determine the effectiveness and efficiency of non-thermal, atmospheric plasmas for inducing polymerization of model dental self-etch adhesives. Methods The monomer mixtures used were bis-[2-(methacryloyloxy)ethyl] phosphate (2MP) and 2-hydroxyethyl methacrylate (HEMA), with mass ratios of 70/30, 50/50 and 30/70. Water was added to the above formulations: 10–30 wt%. These monomer/water mixtures were treated steadily for 40 s under a non-thermal atmospheric plasma brush working at temperatures from 32° to 35°C. For comparison, photo-initiators were added to the above formulations for photo-polymerization studies, which were light-cured for 40 s. The degree of conversion (DC) of both the plasma- and light-cured samples was measured using FTIR spectroscopy with an attenuated total reflectance attachment. Results The non-thermal plasma brush was effective in inducing polymerization of the model self-etch adhesives. The presence of water did not negatively affect the DC of plasma-cured samples. Indeed, DC values slightly increased, with increasing water content in adhesives: from 58.3% to 68.7% when the water content increased from 10% to 30% in the adhesives with a 50/50 (2MP/HEMA) mass ratio. Conversion values of the plasma-cured groups were higher than those of light-cured samples with the same mass ratio and water content. Spectral differences between the plasma- and light-cured groups indicate subtle structural distinctions in the resultant polymer networks. Significance This research if the first to demonstrate that the non-thermal plasma brush induces polymerization of model adhesives under clinical settings by direct/indirect energy transfer. This device shows promise for polymerization of dental composite restorations having enhanced properties and performance. PMID:23018084

  15. Stimuli-Responsive Polyelectrolyte Brushes As a Matrix for the Attachment of Gold Nanoparticles: The Effect of Brush Thickness on Particle Distribution

    Directory of Open Access Journals (Sweden)

    Stephanie Christau

    2014-06-01

    Full Text Available The effect of brush thickness on the loading of gold nanoparticles (AuNPs within stimuli-responsive poly-(N,N-(dimethylamino ethyl methacrylate (PDMAEMA polyelectrolyte brushes is reported. Atom transfer radical polymerization (ATRP was used to grow polymer brushes via a “grafting from” approach. The brush thickness was tuned by varying the polymerization time. Using a new type of sealed reactor, thick brushes were synthesized. A systematic study was performed by varying a single parameter (brush thickness, while keeping all other parameters constant. AuNPs of 13 nm in diameter were attached by incubation. X-ray reflectivity, electron scanning microscopy and ellipsometry were used to study the particle loading, particle distribution and interpenetration of the particles within the brush matrix. A model for the structure of the brush/particle hybrids was derived. The particle number densities of attached AuNPs depend on the brush thickness, as do the optical properties of the hybrids. An increasing particle number density was found for increasing brush thickness, due to an increased surface roughness.

  16. Stepper motor instabilities in an aerospace application

    Science.gov (United States)

    Kackley, Russell; Mccully, Sean

    1992-01-01

    Stepper motors are frequently used in positioning mechanisms because they have several advantages over ordinary DC motors. However, there is frequently no feedback loop and the motor may exhibit instabilities under some conditions. A stepper motor in an aerospace positioning mechanism was investigated. During testing, the motor exhibited unstable behavior, such as backrunning and forward running. The instability was dependent on voltage pulse characteristics, temperature, positioning angle, step rate, and interaction between the two motors in the system. Both testing and analysis results verified the instability. A special purpose FORTRAN code was written to simulate the system. This code was combined with another simpler code to show the performance of the system in the phase plane so that instability boundaries could be displayed along with the motor performance. The analysis was performed to verify that proposed modifications would produce stable performance before implementation in the hardware. Subsequent testing verified the analytic stability predictions.

  17. Brushing force of manual and sonic toothbrushes affects dental hard tissue abrasion

    OpenAIRE

    Wiegand, Annette; Burkhard, John Patrik Matthias; Eggmann, Florin; Attin, Thomas

    2013-01-01

    OBJECTIVES: This study aimed to determine the brushing forces applied during in vivo toothbrushing with manual and sonic toothbrushes and to analyse the effect of these brushing forces on abrasion of sound and eroded enamel and dentin in vitro. MATERIALS AND METHODS: Brushing forces of a manual and two sonic toothbrushes (low and high frequency mode) were measured in 27 adults before and after instruction of the respective brushing technique and statistically analysed by repeated measures ...

  18. Contaminated tooth brushes-potential threat to oral and general health

    OpenAIRE

    Rashmi Naik; B R Ahmed Mujib; Neethu Telagi; B S Anil; B R Spoorthi

    2015-01-01

    Background: Tooth brushing is most common method of maintaining oral hygiene. In removing plaque and other soft debris from the teeth, tooth brushes become contaminated with bacteria, blood, saliva and oral debris. These contaminated tooth brushes can be a source of infection. Aims and objectives: The aim of the present study was to evaluate the presence of microorganisms in the tooth brushes and to investigate the effect of disinfectants such as chlorhexidine gluconate, sodium hypochlorite a...

  19. DC Distribution Systems and Microgrids

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Anvari-Moghaddam, Amjad; Quintero, Juan Carlos Vasquez

    2017-01-01

    A qualitative overview of different hardware topologies and control systems for DC MGs has been presented in this chapter. Some challenges and design considerations of DC protections systems have also been discussed. Finally, applications of DC MGs in emerging smart grid applications have been su...... in different industries and gradually lead to new ways of rethinking of the future power distribution philosophies, especially with the emergence of SSTs. Research in DC systems, especially in the power electronics-based technologies will be highly attractive in the future....

  20. Integrated Multimotor Electrical DC Drive for Metallurgical Rolling Table

    Directory of Open Access Journals (Sweden)

    Gała Marek

    2015-06-01

    Full Text Available A drive system of a section of a metallurgical rolling table consisting of six dc motors, 2220 amperes of total current, fed from a single ABB reversible thyristor converter has been described in this paper. Autonomous excitation circuits of the motors are fed from independent thyristor converters working in the so called MULTIFEX system linked with a supervisory high power converter. There are presented schemes of the DSL communication realized by FEX excitation cards of the motors using the SDSC card of the DCS-800-S02 converter and logic control system based on a PLC controller. The parameterization of the DCS-800 converter and the DCF 803 excitation systems was conducted using the DriveWindow software tool. Significant waveforms of voltages, currents and the estimated motor velocity are described and presented for the idle run as well as during transporting sheets discharged from a pusher furnace.

  1. SCM Handbooks for dc-to-dc Converters

    Science.gov (United States)

    Lee, F.; Mohmoud, M.; Yu, Y.

    1984-01-01

    Two documents aid in design of control modules for dc-to-dc converters. Features of SCM include: Adaptive stability, power component stress limiting, implementation of various control laws, unified design approach. Analysis and quidelines contained in handbooks enable engineer to design SCM circuit and confidently predict resulting overall performance.

  2. Dc-To-Dc Converter Uses Reverse Conduction Of MOSFET's

    Science.gov (United States)

    Gruber, Robert P.; Gott, Robert W.

    1991-01-01

    In modified high-power, phase-controlled, full-bridge, pulse-width-modulated dc-to-dc converters, switching devices power metal oxide/semiconductor field-effect transistors (MOSFET's). Decreases dissipation of power during switching by eliminating approximately 0.7-V forward voltage drop in anti-parallel diodes. Energy-conversion efficiency increased.

  3. The Biomechanics and Motor Control of Tap Dancing.

    Science.gov (United States)

    Rocha, Priscila; McClelland, Jodie; Sparrow, Tony; Morris, Meg E

    2017-09-15

    Although tap dancing is a popular dance genre, little is known about the biomechanics and motor control of this complex motor skill. We conducted a detailed 3D kinematic analysis of movement timing, amplitude, and symmetry in three experienced female tap dancers. Kinematic analyzes of three basic tap dance steps (nerve beats, brush brush stamps, and heel ball walks) were undertaken. A 10-camera Vicon motion analysis system was used to collect the data. The results showed the feet and knees to play a major role in movement execution. Each step required at least 10° of ankle motion (range: 10° to 66.8°). Knee range of motion varied from 1.3° to 147.4°. For each of the dance steps the hips showed the smallest amplitude of movement, which was not greater than 21° in two out of the three dance steps. Analyzes of movement timing showed that each of the dance steps was fast, accurate, and well synchronized. The nerve beats took on average 0.50 seconds, the brush brush stamps 1.36 seconds, and the heel ball walks 4.03 seconds. A high degree of symmetry in total movement amplitude was evident at the ankles,knees, and hips for the nerve beats and heel ball walks. There was a mild degree of asymmetry at the hip for the brush brush stamp steps (symmetry index 90%). The results showed that experienced dancers had very high levels of proficiency in controlling movement amplitude, timing, and inter-limb coordination across the ankles, knees, and hips. This resulted in skilled, fast, and well executed dance steps.

  4. Brush Lettering I; Commercial and Advertising Art--Basic: 9183.05.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The course outline has been prepared as a guide to help the students gain mastery in the proper brush techniques required for efficiency in brush lettering. The student is first given an orientation to the materials and equipment used, and the preparation of tempera paints for brush lettering. After this introduction, the student is guided through…

  5. Enhanced stability of low fouling zwitterionic polymer brushes in seawater with diblock architecture

    NARCIS (Netherlands)

    Quintana, R.; Gosa, M.; Janczewski, D.; Kutnyanszky, E.; Vancso, Gyula J.

    2013-01-01

    The successful implementation of zwitterionic polymeric brushes as antifouling materials for marine applications is conditioned by the stability of the polymer chain and the brush-anchoring segment in seawater. Here we demonstrate that robust, antifouling, hydrophilic polysulfobetaine-based brushes

  6. Early Oscillation Detection Technique for Hybrid DC/DC Converters

    Science.gov (United States)

    Wang, Bright L.

    2011-01-01

    Oscillation or instability is a situation that must be avoided for reliable hybrid DC/DC converters. A real-time electronics measurement technique was developed to detect catastrophic oscillations at early stages for hybrid DC/DC converters. It is capable of identifying low-level oscillation and determining the degree of the oscillation at a unique frequency for every individual model of the converters without disturbing their normal operations. This technique is specially developed for space-used hybrid DC/DC converters, but it is also suitable for most of commercial and military switching-mode power supplies. This is a weak-electronic-signal detection technique to detect hybrid DC/DC converter oscillation presented as a specific noise signal at power input pins. It is based on principles of feedback control loop oscillation and RF signal modulations, and is realized by using signal power spectral analysis. On the power spectrum, a channel power amplitude at characteristic frequency (CPcf) and a channel power amplitude at switching frequency (CPsw) are chosen as oscillation level indicators. If the converter is stable, the CPcf is a very small pulse and the CPsw is a larger, clear, single pulse. At early stage of oscillation, the CPcf increases to a certain level and the CPsw shows a small pair of sideband pulses around it. If the converter oscillates, the CPcf reaches to a higher level and the CPsw shows more high-level sideband pulses. A comprehensive stability index (CSI) is adopted as a quantitative measure to accurately assign a degree of stability to a specific DC/DC converter. The CSI is a ratio of normal and abnormal power spectral density, and can be calculated using specified and measured CPcf and CPsw data. The novel and unique feature of this technique is the use of power channel amplitudes at characteristic frequency and switching frequency to evaluate stability and identify oscillations at an early stage without interfering with a DC/DC converter s

  7. Tooth brushing, tongue cleaning and snacking behaviour of dental ...

    African Journals Online (AJOL)

    2010-08-12

    Aug 12, 2010 ... Objective: To determine the tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students. Methods: A descriptive cross-sectional study of students of Federal School of Dental Therapy and. Technology Enugu, Nigeria. Self-administered questionnaire was used to ...

  8. Preoperative brush and impression cytology in ocular surface squamous neoplasms.

    Science.gov (United States)

    Ersöz, Canan; Yağmur, Meltem; Ersöz, T Reha; Yalaz, Müslime

    2003-01-01

    Preoperative cytologic diagnoses of ocular surface squamous neoplasms were evaluated and compared with histologic diagnoses. Impression cytology (Millipore filter paper) and brush cytology were applied to 32 patients who had conjunctival neoplasms. Papanicolaou-stained cytologic preparations and hematoxylin and eosin-stained histologic sections were examined by light microscopy. The brush technique was used on 27 patients; impression cytology was applied in 5 cases. Cytologic and histologic diagnoses were concordant in 26 cases. Squamous cell carcinoma or carcinoma in situ was diagnosed in 18 and dysplasia in 4 cases. Squamous metaplasia and normal-appearing conjunctival epithelial cells were diagnosed cytologically in four cases; of those histologic diagnoses, one was pterygium and three, conjunctival nevus. Four cases revealed discrepancies between the cytologic and histologic preparations. There was one false positive result, and one case was subconjunctival invasion of basal cell carcinoma of the eyelid. Impression and brush cytology are fast, cost-effective, reliable and noninvasive diagnostic tools for ocular surface squamous neoplasms. However, the brush technique has several advantages over impression cytology.

  9. Polymer brush-functionalized chitosan hydrogels as antifouling implant coatings

    Czech Academy of Sciences Publication Activity Database

    Buzzacchera, I.; Vorobii, M.; Kostina, N. Yu.; de los Santos Pereira, Andres; Riedel, Tomáš; Bruns, M.; Ogieglo, W.; Möller, M.; Wilson, C. J.; Rodriguez-Emmenegger, C.

    2017-01-01

    Roč. 18, č. 6 (2017), s. 1983-1992 ISSN 1525-7797 R&D Projects: GA ČR(CZ) GBP205/12/G118 Institutional support: RVO:61389013 Keywords : chitosan * hemocompatible * polymer brushes Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 5.246, year: 2016

  10. Tooth brushing, tongue cleaning and snacking behaviour of dental ...

    African Journals Online (AJOL)

    2010-08-12

    Aug 12, 2010 ... Objective: To determine the tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist ... Keywords: toothbrushing; tongue cleaning; snacking behaviour; dental auxiliary students; Nigeria. Received: 9 April 2010; .... patients are not able to achieve sufficient plaque removal.

  11. Bacterial adhesion and growth on a polymer brush-coating

    NARCIS (Netherlands)

    Nejadnik, M.R.; Mei, van der H.C.; Norde, W.; Busscher, H.J.

    2008-01-01

    Biomaterials-related infections pose serious problems in implant surgery, despite the development of non-adhesive coatings. Non-adhesive coatings, like polymer brush-coatings, have so far only been investigated with respect to preventing initial bacterial adhesion, but never with respect to effects

  12. Keep Kids' Mouths Healthy: Brush 2min2X

    Science.gov (United States)

    ... motions. Repeat this process for each and every tooth. Brushing and Flossing is Important Use fluoride Use Fluoride Fluoride is nature’s cavity fighter and occurs naturally in water and some foods. To help protect teeth from cavities, fluoride is added to dental products ...

  13. Organic monolayers and fluoropolymer brushes : functionalization, stability and tribology

    NARCIS (Netherlands)

    Bhairamadgi, N.S.

    2014-01-01

    This thesis deals with the adhesion and friction properties of densely grafted and covalently bound fluoropolymer brushes on silicon surfaces with varying thickness and fluorine content. A novel surface-functionalizing method is described using the thiol-yne click (TYC) reaction. The TYC reaction is

  14. Wetting phase diagrams of polyacid brush with a triple point.

    NARCIS (Netherlands)

    Mercurieva, A.A.; Iakovlev, P.A.; Zhulina, E.B.; Birshtein, T.M.; Leermakers, F.A.M.

    2006-01-01

    The (pre)wetting behavior of an annealed polyelectrolyte (PE) brush by an electrolyte solution that is strongly segregated from an apolar phase is analyzed. In this complex interface, there are interactions on various length scales. There are short-range interactions with the (uncharged) surface,

  15. Clickable antifouling polymer brushes for polymer pen lithography

    Czech Academy of Sciences Publication Activity Database

    Bog, U.; de los Santos Pereira, Andres; Mueller, S. L.; Havenridge, S.; Parrillo, Viviana; Bruns, M.; Holmes, A. E.; Rodriguez-Emmenegger, C.; Fuchs, H.; Hirtz, M.

    2017-01-01

    Roč. 9, č. 13 (2017), s. 12109-12117 ISSN 1944-8244 R&D Projects: GA ČR(CZ) GJ15-09368Y Institutional support: RVO:61389013 Keywords : antifouling * biofunctional interfaces * polymer brushes Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 7.504, year: 2016

  16. Self-organization of multivalent counterions in polyelectrolyte brushes

    Science.gov (United States)

    Wu, Jianzhong

    2013-03-01

    The structure and interfacial properties of a polyelectrolyte brush (PEB) depend on a broad range of parameters such as the polymer charge and grafting density, counterion valence, salt concentration, and solvent conditions. These properties are of fundamental importance in technological applications of PEBs including colloid stabilization, surface modification and lubrication, and in functioning of biological systems such as genome packaging in single-strand DNA/RNA viruses. Despite intensive studies by experiments, molecular simulations, and myriad analytical methods including scaling analyses, self-consistent-field theory, and most recently density functional theory, the behavior of PEBs in the presence of multivalent counterions remains poorly understood. In this talk, I will present a density functional method for polyelectrolyte brushes and discuss self-organization of multivalent counterions within highly charged polyelectrolyte brushes. The counterion-mediated attraction between polyions leads to a first-order phase transition similar to that for a neutral brush in a poor solvent. The self-organization of multivalent counterions results in a wavelike electrostatic potential and charge density that oscillate between positive and negative values.

  17. Tooth brushing, tongue cleaning and snacking behaviour of dental ...

    African Journals Online (AJOL)

    Objective: To determine the tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students. Methods: A descriptive cross-sectional study of students of Federal School of Dental Therapy and Technology Enugu, Nigeria. Self-administered questionnaire was used to obtain information on ...

  18. Immunoelectrophoretic studies on pig intestinal brush border proteins

    DEFF Research Database (Denmark)

    Danielsen, Erik Michael; Sjöström, H; Norén, O

    1977-01-01

    Brush borders were prepared from pig intestinal mucosa and the membrane proteins solubilized with either Triton X-100 or papain. Proteins, thus released, were used as antigens to raise antisera in rabbits. The immunoglobulin G fractions were isolated and shown by the double layer immunofluorescence...

  19. Development of a DC propulsion system for an electric vehicle

    Science.gov (United States)

    Kelledes, W. L.

    1984-01-01

    The suitability of the Eaton automatically shifted mechanical transaxle concept for use in a near-term dc powered electric vehicle is evaluated. A prototype dc propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the contractor's site. The system consisted of a two-axis, three-speed, automatically-shifted mechanical transaxle, 15.2 Kw rated, separately excited traction motor, and a transistorized motor controller with a single chopper providing limited armature current below motor base speed and full range field control above base speed at up to twice rated motor current. The controller utilized a microprocessor to perform motor and vehicle speed monitoring and shift sequencing by means of solenoids applying hydraulic pressure to the transaxle clutches. Bench dynamometer and track testing was performed. Track testing showed best system efficiency for steady-state cruising speeds of 65-80 Km/Hz (40-50 mph). Test results include acceleration, steady speed and SAE J227A/D cycle energy consumption, braking tests and coast down to characterize the vehicle road load.

  20. Hydrologic Effects of Brush Management in Central Texas

    Science.gov (United States)

    Banta, J. R.; Slattery, R.

    2011-12-01

    Encroachment of woody vegetation into traditional savanna grassland ecosystems in central Texas has largely been attributed to land use practices of settlers, most notably overgrazing and fire suppression. Implementing brush management practices (removing the woody vegetation and allowing native grasses to reestablish in the area), could potentially change the hydrology in a watershed. The U.S. Geological Survey, in cooperation with several local, State, and Federal cooperators, studied the hydrologic effects of ashe juniper (Juniperus ashei) removal as a brush management conservation practice in the Honey Creek State Natural Area in Comal County, Tex. Two adjacent watersheds of 104 and 159 hectares were used in a paired study. Rainfall, streamflow, evapotranspiration (Bowen ratio method), and water quality data were collected in both watersheds. Using a hydrologic mass balance approach, rainfall was allocated to surface-water runoff, evapotranspiration, and groundwater recharge. Groundwater recharge was not directly measured, but estimated as the residual of the hydrologic mass balance. After hydrologic data were collected in both watersheds for 3 years, approximately 80 percent of the woody vegetation (ashe juniper) was selectively removed from the 159 hectare watershed (treatment watershed). Brush management was not implemented in the other (reference) watershed. Hydrologic data were collected in both watersheds for six years after brush management implementation. The resulting data were examined for differences in the hydrologic budget between the reference and treatment watersheds as well as between pre- and post-brush management periods to assess effects of the treatment. Preliminary results indicate there are differences in the hydrologic budget as well as water quality between the watersheds during pre- and post-treatment periods.

  1. Clickable Antifouling Polymer Brushes for Polymer Pen Lithography.

    Science.gov (United States)

    Bog, Uwe; de Los Santos Pereira, Andres; Mueller, Summer L; Havenridge, Shana; Parrillo, Viviana; Bruns, Michael; Holmes, Andrea E; Rodriguez-Emmenegger, Cesar; Fuchs, Harald; Hirtz, Michael

    2017-04-05

    Protein-repellent reactive surfaces that promote localized specific binding are highly desirable for applications in the biomedical field. Nonspecific adhesion will compromise the function of bioactive surfaces, leading to ambiguous results of binding assays and negating the binding specificity of patterned cell-adhesive motives. Localized specific binding is often achieved by attaching a linker to the surface, and the other side of the linker is used to bind specifically to a desired functional agent, as e.g. proteins, antibodies, and fluorophores, depending on the function required by the application. We present a protein-repellent polymer brush enabling highly specific covalent surface immobilization of biorecognition elements by strain-promoted alkyne-azide cycloaddition click chemistry for selective protein adhesion. The protein-repellent polymer brush is functionalized by highly localized molecular binding sites in the low micrometer range using polymer pen lithography (PPL). Because of the massive parallelization of writing pens, the tunable PPL printed patterns can span over square centimeter areas. The selective binding of the protein streptavidin to these surface sites is demonstrated while the remaining polymer brush surface is resisting nonspecific adsorption without any prior blocking by bovine serum albumin (BSA). In contrast to the widely used BSA blocking, the reactive polymer brushes are able to significantly reduce nonspecific protein adsorption, which is the cause of biofouling. This was achieved for solutions of single proteins as well as complex biological fluids. The remarkable fouling resistance of the polymer brushes has the potential to improve the multiplexing capabilities of protein probes and therefore impact biomedical research and applications.

  2. The effect of brushing time and dentifrice on dental plaque removal in vivo.

    Science.gov (United States)

    Creeth, Jonathan E; Gallagher, Andrew; Sowinski, Joseph; Bowman, James; Barrett, Kathy; Lowe, Shirley; Patel, Kartik; Bosma, Mary Lynn

    2009-01-01

    Routine toothbrushing is the principal method by which individuals remove plaque and control plaque-related diseases, such as periodontitis and caries. Oral health care professionals generally recommend at least 2 minutes brushing with an appropriate technique, and yet the average brushing time in the general population is closer to 45 seconds. Our understanding of the relationship between brushing time and plaque removal, in an untutored general population using a conventional manual toothbrush and dentifrice, is limited. The role of dentifrice in plaque removal is also unclear. This study was undertaken to measure plaque removal during untutored brushing over timed periods between 30 and 180 seconds with 1.5 g dentifrice, using an Aquafresh Flex brush and Aquafresh Advanced dentifrice. Plaque removal after brushing without dentifrice was also determined (at the 60 second time point only). Forty-seven subjects participated in the study, in which plaque level was assessed using the Quigley-Hein (Turesky-modification) Index. Plaque removal increased with brushing time across the range studied, tending towards a maximum at longer brushing times. At the extremes, brushing for 180 seconds removed 55% more plaque than brushing for 30 seconds. Brushing for 120 seconds removed 26% more plaque than brushing for 45 seconds. The use of dentifrice did not increase plaque removal during 60 seconds of brushing. Oral health care professionals should reinforce efforts to persuade patients to brush for longer periods of time, as increasing brushing time to the consensus minimum of 2 minutes from a more typical 45 seconds increases plaque removal to an extent likely to provide clinically significant oral health benefits.

  3. Buried, Covalently Attached RGD Peptide Motifs in Poly(methacryllic) Brush Layers; The Effect of Brush Structure on Cell Adhesion

    NARCIS (Netherlands)

    Navarro, Melba; Benetti, Edmondo Maria; Zapotoczny, S.J.; Planell, Josep A.; Vancso, Gyula J.

    2008-01-01

    Iniferter-mediated surface-initiated photopolymerization was used to graft poly(methacrylic acid) (PMAA) brush layers obtained from surface-attached iniferters in self-assembled monolayers to a gold surface. The tethered chains were subsequently functionalized with the cell-adhesive

  4. Modular Power System Configured with Standard Product Hybrid DC-DC Converters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VPT proposes an innovative concept whereby complex, multiple-output, DC-DC converter systems can be configured through use of only 2 standard product hybrid DC-DC...

  5. Triple voltage dc-to-dc converter and method

    Science.gov (United States)

    Su, Gui-Jia

    2008-08-05

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  6. Bi-Directional DC-DC Converter for PHEV Applications

    Energy Technology Data Exchange (ETDEWEB)

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  7. Evaluation of multi-brush anode systems in microbial fuel cells

    KAUST Repository

    Lanas, Vanessa

    2013-11-01

    The packing density of anodes in microbial fuel cells (MFCs) was examined here using four different graphite fiber brush anode configurations. The impact of anodes on performance was studied in terms of carbon fiber length (brush diameter), the number of brushes connected in parallel, and the wire current collector gage. MFCs with different numbers of brushes (one, three or six) set perpendicular to the cathode all produced similar power densities (1200±40mW/m2) and coulombic efficiencies (60%±5%). Reducing the number of brushes by either disconnecting or removing them reduced power, demonstrating the importance of anode projected area covering the cathode, and therefore the need to match electrode projected areas to maintain high performance. Multi-brush reactors had the same COD removal as single-brush systems (90%). The use of smaller Ti wire gages did not affect power generation, which will enable the use of less metal, reducing material costs. © 2013 Elsevier Ltd.

  8. On-demand degrafting of polymer brushes prepared by controlled radical polymerization on flat silica substrates

    Science.gov (United States)

    Patil, Rohan; Srogl, Jiri; Kiserow, Douglas; Genzer, Jan

    2014-03-01

    Polymer brush degrafting refers to the removal of grafted polymer chains from the substrate without harming the polymer chemical structure. We grow poly(methyl methacrylate) (PMMA) brushes on flat silicon substrates using atom transfer radical polymerization (ATRP) and remove them from the surface by exposing the samples to tetrabutyl ammonium fluoride. We then analyze the polymer molecular weight of degrafted PMMA chains by size exclusion chromatography. The kinetics of PMMA brush degrafting exhibits double exponential behavior suggesting a transition from `brush' to `mushroom' regime. The dry brush thickness increases initially with increasing polymerization time. At longer reaction times, the thickness starts to plateau due to loss in the living nature of ATRP. We examine the relationship between the brush dry thickness and molecular weight and show that grafting density of the PMMA brush does not remain constant over the course of polymerization but reduces with time.

  9. Tooth brushing frequency and risk of new carious lesions.

    Science.gov (United States)

    Holmes, Richard D

    2016-12-01

    Data sourcesMedline, Embase, CINHAL and the Cochrane databases.Study selectionTwo reviewers selected studies, and case-control, prospective cohort, retrospective cohort and experimental trials evaluating the effect of toothbrushing frequency on the incidence or increment of new carious lesions were considered.Data extraction and synthesisTwo reviewers undertook data abstraction independently using pre-piloted forms. Study quality was assessed using a quality assessment tool for quantitative studies developed by the Effective Public Health Practice Project (EPHPP). Meta-analysis of caries outcomes was carried out using RefMan and meta-regressions undertaken to assess the influence of sample size, follow-up period, caries diagnosis level and study methodological quality.ResultsThirty-three studies were included of which 13 were considered to be methodologically strong, 14 moderate and six weak. Twenty-five studies contributed to the quantitative analysis. Compared with frequent brushers, self-reported infrequent brushers demonstrated a higher incidence of carious lesions, OR=1.50 (95%CI: 1.34 -1.69). The odds of having carious lesions differed little when subgroup analysis was conducted to compare the incidence between ≥2 times/d vs Brushing brushing, standardised mean difference [SMD] =0.34; (95%CI; 0.18 - 0.49). Overall, infrequent brushing was associated with an increment of carious lesions, SMD= 0.28; (95%CI; 0.13 - 0.44). Meta-analysis conducted with the type of dentition as subgroups found the effect of infrequent brushing on incidence and increment of carious lesions was higher in deciduous, OR=1.75; (95%CI; 1.49 - 2.06) than permanent dentition OR=1.39; (95% CI: 1.29 -1.49). Meta-regression indicated that none of the included variables influenced the effect estimate.ConclusionsIndividuals who state that they brush their teeth infrequently are at greater risk for the incidence or increment of new carious lesions than those brushing more frequently. The

  10. Early response of ponderosa pine to spacing and brush: observations on a 12-year-old plantation

    Science.gov (United States)

    William W. Oliver

    1979-01-01

    Ponderosa pine (Pinus ponderosa Laws.) was planted at five different spacings, from 6 by 6 to 18 by 18 feet, on a productive site in northern California. Spacing and brush effects on tree growth were evaluated both on plots where brush was allowed to develop and on plots kept free of brush. Competition between trees in brush-free plots began during...

  11. New propulsion components for electric vehicles

    Science.gov (United States)

    Secunde, R. R.

    1983-01-01

    Improved component technology is described. This includes electronically commutated permanent magnet motors of both drum and disk configurations, an unconventional brush commutated motor, ac induction motors, various controllers, transmissions and complete systems. One or more of these approaches to electric vehicle propulsion may eventually displace presently used controllers and brush commutated dc motors. Previously announced in STAR as N83-25982

  12. Step-Up DC-DC Power Converter

    DEFF Research Database (Denmark)

    2015-01-01

    capacitor coupled between the positive and negative input terminals and the secondary side circuit comprises an output capacitor chargeable to a converter output voltage between a first positive electrode and a second negative electrode. A switched energy storage network is configured for alternatingly...... being charged from the input voltage and discharged to the output capacitor through the galvanic isolation barrier in accordance with a switch control signal to produce the converter output voltage. The step-up DC-DC power converter comprises an electrical short-circuit connection across the galvanic......The present invention relates to a step-up DC-DC power converter which comprises a primary side circuit and a secondary side circuit coupled through a galvanic isolation barrier. The primary side circuit comprises a positive and a negative input terminal for receipt of an input voltage and an input...

  13. Active pre-filters for dc/dc Boost regulators

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Ramos-Paja

    2014-05-01

    Full Text Available This paper proposes an active pre-filter to mitigate the current harmonics generated by classical dc/dc Boost regulators, which generate current ripples proportional to the duty cycle. Therefore, high output voltage conditions, i.e., high voltage conversion ratios, produce high current harmonics that must be filtered to avoid damage or source losses. Traditionally, these current components are filtered using electrolytic capacitors, which introduce reliability problems because of their high failure rate. The solution introduced in this paper instead uses a dc/dc converter based on the parallel connection of the Boost canonical cells to filter the current ripples generated by the Boost regulator, improving the system reliability. This solution provides the additional benefits of improving the overall efficiency and the voltage conversion ratio. Finally, the solution is validated with simulations and experimental results.

  14. Fuzzy Control of DC-DC Converters with Input Constraint

    Directory of Open Access Journals (Sweden)

    D. Saifia

    2012-01-01

    Full Text Available This paper proposes a method for designing fuzzy control of DC-DC converters under actuator saturation. Because linear control design methods do not take into account the nonlinearity of the system, a T-S fuzzy model and a controller design approach is used. The designed control not only handles the external disturbance but also the saturation of duty cycle. The input constraint is first transformed into a symmetric saturation which is represented by a polytopic model. Stabilization conditions for the state feedback system of DC-DC converters under actuator saturation are established using the Lyapunov approach. The proposed method has been compared and verified with a simulation example.

  15. Decentralized Interleaving of Paralleled Dc-Dc Buck Converters

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sinha, Mohit [University of Minnesota; Dhople, Sairaj [University of Minnesota; Poon, Jason [University of California at Berkeley

    2017-08-21

    We present a decentralized control strategy that yields switch interleaving among parallel-connected dc-dc buck converters. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform and no communication between different controllers is needed. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work presents the first fully decentralized strategy for switch interleaving in paralleled dc-dc buck converters.

  16. Decentralized Interleaving of Paralleled Dc-Dc Buck Converters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sinha, Mohit [University of Minnesota; Dhople, Sairaj [University of Minnesota; Poon, Jason [University of California at Berkeley

    2017-09-01

    We present a decentralized control strategy that yields switch interleaving among parallel connected dc-dc buck converters without communication. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy for switch interleaving of paralleled dc-dc buck converters.

  17. RESONANT STEP-DOWN DC-DC POWER CONVERTERS

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a resonant step-down DC-DC power converter which comprises a primary side circuit and a secondary side circuit coupled through a galvanic isolation barrier. The primary side circuit comprises a positive and a negative input terminal for receipt of an input voltage...... charged from the input voltage and discharged to the output capacitor through the galvanic isolation barrier by a semiconductor switch arrangement in accordance with a switch control signal to produce the converter output voltage. The resonant step-down DC-DC power converter comprises an electrical short......-circuit connection across the galvanic isolation barrier connecting, in a first case, the second negative electrode of the output capacitor to the positive input terminal of the primary side circuit or, in a second case, connecting the second positive electrode of the output capacitor to the negative input terminal...

  18. Sensorless induction motor drive for electric vehicle application ...

    African Journals Online (AJOL)

    This approach is applied to an existing commercial utility electric vehicle where previously used direct current (DC) series motor was replaced by the new AC induction ... induction motor, field oriented control, sensorless control. International Journal of Engineering, Science and Technology, Vol. 2, No. 10, 2010, pp. 20-34 ...

  19. PMBLDC motor drive with power factor correction controller

    DEFF Research Database (Denmark)

    George, G.J.; Ramachandran, Rakesh; Arun, N.

    2012-01-01

    This paper presents a boost converter configuration, control scheme and design of single phase power factor controller for permanent magnet brushless DC motor (PMBLDCM) drive. PMBLDC motors are the latest choice of researchers, due to the high efficiency, silent operation, compact size, high...

  20. DC BLOWER MOTOR OPERATED COOLER WITH SOLAR PANEL

    OpenAIRE

    Krishan Kumar*, Naresh

    2016-01-01

    cooler with solar panel for residential Cooling is very important during the summer as well as in the life to maintain the food, fish, and many items at constant temperature to avoid the bad effect of viruses’. But air cooling is very important part during the summer for a man. Cooling process employs the different method to cool the air. Today air cooling methods are very expensive for AC coolers, air conditioning, fans and dehumidifiers. To running these products required Ac supply/el...

  1. Pulsewidth Modulated Speed Control of Brushless DC Motors.

    Science.gov (United States)

    1984-09-01

    voltaje across the inductor terminals, owing to a rapid rate of change in the inductor current. This induced voltage turns on diode Dr, whicn provides a... voltaje relation~zip as sho.w;. in ey uation 4.9: V il. + Ll) di/dt + Pi + K, *w (k2 !1- -4. .ii;the: !Lapiace trarnsl-orm o f e,,uation ~5vls 36 S I E

  2. Permanent magnet synchronous and brushless DC motor drives

    CERN Document Server

    Ramu, Krishnan

    2009-01-01

    Presents an introduction to machines, power devices, inverters, and control. This book covers pm synchronous machines, including modeling, implementation, control strategies, flux weakening operations, parameter sensitivity, sensorless control, and intelligent control applications.

  3. DC-Compensated Current Transformer.

    Science.gov (United States)

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-20

    Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component.

  4. A randomized clinical trial evaluating gingivitis and plaque reduction of an oscillating-rotating power brush with a new brush head with angled bristles versus a marketed sonic brush with self-adjusting technology.

    Science.gov (United States)

    Klukowska, Malgorzata; Grender, Julie M; Conde, Erinn; Ccahuana-Vasquez, Renzo Alberto; Ram Goyal, C

    2014-08-01

    To compare the efficacy of an oscillating-rotating power toothbrush with a novel brush head incorporating angled CrissCross bristles (Oral-B Pro 7000 SmartSeries and Oral-B CrossAction brush head) versus a marketed sonic toothbrush (Colgate ProClinical A1500 with the Triple Clean brush head) in the reduction of gingivitis and plaque over a 6-week period. This was a single center, randomized, open label, examiner-blind, 2-treatment, parallel group study. Study participants who met the entrance criteria were enrolled in the study and randomly assigned to one of the two toothbrush groups. Study participants brushed with their assigned toothbrush and a marketed fluoride dentifrice for 2 minutes twice daily at home for 6 weeks. Gingivitis and plaque were evaluated at baseline and Week 6. Gingivitis was assessed using the Modified Gingival Index (MGI) and Gingival Bleeding Index (GBI) and plaque was assessed using the Rustogi Modified Navy Plaque Index (RMNPI). Data was analyzed using the ANCOVA with baseline as the covariate. In total, 130 study participants were randomized to treatment resulting in 64 study participants per group completing the study. Both brushes produced statistically significant (P gingivitis and plaque measures relative to baseline. The oscillating-rotating,brush with the novel brush head demonstrated statistically significantly (P gingivitis measures, as well as whole mouth and interproximal plaque measures, compared to the sonic toothbrush. The benefit for the oscillating- rotating brush over the sonic brush was 21.3% for gingivitis, 35.7% for gingival bleeding, 34.7% for number of bleeding sites, 17.4% for whole mouth plaque, and 21.2% for interproximal plaque. There were no adverse events reported or observed for either brush.

  5. DC injection into low voltage AC networks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report summarises the results of a study investigating the impact of levels of injected DC current injections on a low voltage AC distribution network systems in order to recommend acceptable limits of DC from microgeneration. Relevant literature is reviewed, and the impact of DC levels in distribution transformers, transformer modelling, and instrumental transformers are discussed. The impact of DC in residual current devices (RCD) and in domestic electricity watt hour meters is examined along with DC enhanced corrosion, corrosion failure, and the measurement of DC current injection. Sources of DC injection outlined include DC from computer power supplies, network faults, geomagnetic phenomena, lighting circuits/dimmers, and embedded generators.

  6. Digital Control Technologies for Modular DC-DC Converters

    Science.gov (United States)

    Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

    2002-01-01

    Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.

  7. Comparative Study on Photovoltaic Pumping Systems Driven by Different Motors Optimized with Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Abdelhak Bouchakour

    2017-06-01

    Full Text Available This study investigates the performance of three different photovoltaic (PV water pumping systems driven by three types of motors, namely a separately excited DC motor (DCM, an asynchronous motor (ASM, and a permanent magnet synchronous motor (PMSM, via a DC/DC buck-boost converter coupled to a centrifugal pump. The purpose of this study is to implement a fast and robust control for this type of a nonlinear system, controlled by sliding mode (SM. This paper presents an SM control technique for controlling a DC/DC buck-boost converter to transfer the maximum power delivered by the PV generator. Each component is studied and analyzed to simulate the global system in MATLAB/SIMULINK. The three systems are then compared to determine the overall effectiveness of the proposed command. The study concludes that the ASM-driven PV system yields highly favorable results and requires less maintenance compared with other systems.

  8. R dump converter without DC link capacitor for an 8/6 SRM: experimental investigation.

    Science.gov (United States)

    Kavitha, Pasumalaithevan; Umamaheswari, Bhaskaran

    2015-01-01

    The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM) when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation.

  9. R Dump Converter without DC Link Capacitor for an 8/6 SRM: Experimental Investigation

    Directory of Open Access Journals (Sweden)

    Pasumalaithevan Kavitha

    2015-01-01

    Full Text Available The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation.

  10. R Dump Converter without DC Link Capacitor for an 8/6 SRM: Experimental Investigation

    Science.gov (United States)

    Kavitha, Pasumalaithevan; Umamaheswari, Bhaskaran

    2015-01-01

    The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM) when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation. PMID:25642452

  11. Brush reduces growth of thinned ponderosa pine in northern California

    Science.gov (United States)

    William W. Oliver

    1984-01-01

    The effects of tree spacing and brush competition were evaluated on a ponderosa pine (Pinus ponderosa Dougl. ex Laws. var. ponderosa) site of low productivity in California's North Coast Range. Eleven-year-old saplings were thinned to square spacings of 2.1, 2.4, 3.0, and 4.3 m (7, 8, 10, and 14 ft), and all, half, and none of...

  12. Assessment of Pain Response in Capsaicin-Induced Dynamic Mechanical Allodynia Using a Novel and Fully Automated Brushing Device

    Directory of Open Access Journals (Sweden)

    Kristian G du Jardin

    2013-01-01

    Full Text Available BACKGROUND: Dynamic mechanical allodynia is traditionally induced by manual brushing of the skin. Brushing force and speed have been shown to influence the intensity of brush-evoked pain. There are still limited data available with respect to the optimal stroke number, length, force, angle and speed. Therefore, an automated brushing device (ABD was developed, for which brushing angle and speed could be controlled to enable quantitative assessment of dynamic mechanical allodynia.

  13. DC Microgrids – Part I

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Lu, Xiaonan; Quintero, Juan Carlos Vasquez

    2016-01-01

    This paper presents a review of control strategies, stability analysis and stabilization techniques for DC microgrids (MGs). Overall control is systematically classified into local and coordinated control levels according to respective functionalities in each level. As opposed to local control...

  14. A Comparison of C-Shaped and Brush Armature Performance

    Science.gov (United States)

    Wild, Barbara; Alouahabi, Farid; Simicic, Dejan; Schneider, Markus; Hoffman, Ryan

    2017-07-01

    The most important part of a railgun launch package is the armature where the electromagnetic force is generated leading to the acceleration of the launch package. In case of metal armatures, the most commonly used armature types are the C-shape and the multi-fiber brush technology. However, rarely both armature types were systematically compared under similar experimental conditions. That is why we constructed launch packages based on the C-shaped and brush armature technology with comparable armature and payload mass. With these launch packages a series of experiments were performed in an energy range between 0.8 MJ and 1.13 MJ corresponding to a speed range between 950 m/s and 1400 m/s. The results of the experiments were then analyzed qualitatively and quantitatively. On the one hand our results show that the total losses are higher for the C-shaped armature technology than for the brush aramture technology. On the other hand our results show that launch packages based on the C-shaped technology convert better electrical energy into kinetic energy.

  15. Linking DC together with TRSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne Elisabeth; Yong, X.

    2000-01-01

    Duration Calculus (DC) is an interval-based real-time logic, which can be used in capturing and eliciting users' real-time requirements. The Timed RAISE Specification Language (TRSL) is an extension of the RAISE Specification Language with real-time features. This paper links DC and TRSL together...... approach for linking state-based real-time logics together with event-based, timed process algebra languages....

  16. How pre-school children learn to brush their teeth in Sharjah, United Arab Emirates.

    Science.gov (United States)

    Khadri, F A; Gopinath, V K; Hector, M P; Davenport, E S

    2010-05-01

    The objective of this cross-sectional study was to assess tooth brushing habits of pre-school children and to determine the role and amount of supervision given to them by their parents. One hundred pre-school children below 6 years were selected from Maternal and Child Health Center, Sharjah (United Arab Emirates, UAE). A standard piloted questionnaire was used to collect socio-demographic details and information on oral hygiene practise. Tooth brushing was stared at a mean age of 16 months. Thirty-seven per cent of the pre-schoolers used a toothbrush for cleaning their teeth and the brushing habits were mainly (70%) introduced by mothers. The majority (80%) of children's tooth brushing at the age of 3 years and above was supervised by mothers. Younger children were frequently supervised in tooth brushing than older children (P brushing at a mean age of 16 months. Mothers played a pivotal role in introducing and teaching the child how to brush. There was no positive correlation between the brushing behaviour of the mothers and their children. In most cases, the children's brushing was supervised by their mother when they were above 25 months of age. In children less than 12 months of age tooth brushing was not started at all.

  17. Boundary lubrication by brushed salivary conditioning films and their degree of glycosylation.

    Science.gov (United States)

    Veeregowda, Deepak H; van der Mei, Henny C; de Vries, Joop; Rutland, Mark W; Valle-Delgado, Juan J; Sharma, Prashant K; Busscher, Henk J

    2012-10-01

    Toothbrushing, though aimed at biofilm removal, also affects the lubricative function of adsorbed salivary conditioning films (SCFs). Different modes of brushing (manual, powered, rotary-oscillatory or sonically driven) influence the SCF in different ways. Our objectives were to compare boundary lubrication of SCFs after different modes of brushing and to explain their lubrication on the basis of their roughness, dehydrated layer thickness, and degree of glycosylation. A pilot study was performed to relate in vitro lubrication with mouthfeel in human volunteers. Coefficient of friction (COF) on 16-h-old SCFs after manual, rotary-oscillatory, and sonically driven brushing was measured using colloidal probe atomic force microscopy (AFM). AFM was also used to assess the roughness of SCFs prior to and after brushing. Dehydrated layer thicknesses and glycosylation of the SCFs were determined using X-ray photoelectron spectroscopy. Mouthfeel after manual and both modes of powered brushing were evaluated employing a split-mouth design. Compared with unbrushed and manually or sonically driven brushed SCFs, powered rotary-oscillatory brushing leads to deglycosylation of the SCF, loss of thickness, and a rougher film. Concurrently, the COF of a powered rotary-oscillatory brushed SCF increased. Volunteers reported a slightly preferred mouthfeel after sonic brushing as compared to powered rotating-oscillating brushing. Deglycosylation and roughness increase the COF on SCFs. Powered rotary-oscillatory brushing can deglycosylate a SCF, leading to a rougher film surface as compared with manual and sonic brushing, decreasing the lubricative function of the SCF. This is consistent with clinical mouthfeel evaluation after different modes of brushing.

  18. Two-phase induction motor drives

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Lungeanu, Florin; Skaug, Kenneth

    2004-01-01

    There is a continuous debate today concerning the ?motor of the future? for low-power applications requiring less than 1-2 kW. The specialists are focusing on superior motors [1] like brushless-dc, permanent-magnet synchronous, or electronically commutated types, because they show improvements...... in efficiency, reliability, torque-per-volume/mass ratio, maintenance, and service life. Despite this effort, the industry seems to be responding with manifest rigidity in changing standard induction motor solutions when considering the installed volume into the field, the investment in manufacturing base...

  19. High Temperature Silicon Carbide (SiC) Traction Motor Drive

    Science.gov (United States)

    2011-08-09

    board with integrated busbars is necessary. These arrays can be seen in Figure 13. In order to withstand the thermal environment within the motor...chassis isolation. Insulation of busbars , use of insulation barriers, careful orientation of components for optimum power flow, and selection and...motor drive. Busbar connections are provided for input DC power as well as output AC power to the motor. A single circular military style

  20. Comparative analysis of some brushless motors based on catalog data

    Directory of Open Access Journals (Sweden)

    Anton Kalapish

    2005-10-01

    Full Text Available Brushless motors (polyphased AC induction, synchronous and brushless DC motors have no alternatives in modern electric drives. They possess highly efficient and very wide range of speeds. The objective of this paper is to represent some relation between the basic parameters and magnitudes of electrical machines. This allows to be made a comparative analysis and a choice of motor concerning each particular case based not only on catalogue data or price for sale.

  1. Control of the Doubly Salient Permanent Magnet Switched Reluctance Motor

    OpenAIRE

    Merrifield, David Bruce

    2010-01-01

    The permanent magnet switched reluctance motor (PMSRM) is hybrid dc motor which has the potential to be more effect than the switched reluctance (SRM) and permanent magnet (PM) motors. The PMSRM has a both a salient rotor and stator with permanent magnets placed directly onto the face of common pole stators. The PMSRM is wound like the SRM and can be controlled by the same family of converters. The addition of permanent magnets creates nonlinearities in both the governing electrical and me...

  2. Motor teams :

    Indian Academy of Sciences (India)

    . Switch. Welte et al, 1998, Gross et al, 2002. Motion of Lipid droplets in Drosophila embryos. Page 7. • Stochastic transitions between two species of motor yields Bidirectional motion. • Tuning of single-motor parameters. • No need to invoke a ...

  3. Discriminatory bio-adhesion over nano-patterned polymer brushes

    Science.gov (United States)

    Gon, Saugata

    Surfaces functionalized with bio-molecular targeting agents are conventionally used for highly-specific protein and cell adhesion. This thesis explores an alternative approach: Small non-biological adhesive elements are placed on a surface randomly, with the rest of the surface rendered repulsive towards biomolecules and cells. While the adhesive elements themselves, for instance in solution, typically exhibit no selectivity for various compounds within an analyte suspension, selective adhesion of targeted objects or molecules results from their placement on the repulsive surface. The mechanism of selectivity relies on recognition of length scales of the surface distribution of adhesive elements relative to species in the analyte solution, along with the competition between attractions and repulsions between various species in the suspension and different parts of the collecting surface. The resulting binding selectivity can be exquisitely sharp; however, complex mixtures generally require the use of multiple surfaces to isolate the various species: Different components will be adhered, sharply, with changes in collector composition. The key feature of these surface designs is their lack of reliance on biomolecular fragments for specificity, focusing entirely on physicochemical principles at the lengthscales from 1 - 100 nm. This, along with a lack of formal patterning, provides the advantages of simplicity and cost effectiveness. This PhD thesis demonstrates these principles using a system in which cationic poly-L-lysine (PLL) patches (10 nm) are deposited randomly on a silica substrate and the remaining surface is passivated with a bio-compatible PEG brush. TIRF microscopy revealed that the patches were randomly arranged, not clustered. By precisely controlling the number of patches per unit area, the interfaces provide sharp selectivity for adhesion of proteins and bacterial cells. For instance, it was found that a critical density of patches (on the order of

  4. Molecular motors

    Science.gov (United States)

    Allemand, Jean François Desbiolles, Pierre

    2015-10-01

    How do we move? More precisely, what are the molecular mechanisms that can explain that our muscles, made of very small components can move at a osopic scale? To answer these questions we must introduce molecular motors. Those motors are proteins, or small protein assemblies that, in our cells, transform chemical energy into mechanical work. Then, like we could do for a oscopic motor, used in a car or in a fan, we are going to study the basic behavior of these molecular machines, present what are their energy sources, calculate their power, their yield. If molecular motors are crucial for our oscopic movements, we are going to see that they are also essential to cellular transport and that considering the activity of some enzymes as molecular motors bring some interesting new insights on their activity.

  5. Design of an Electric Commutated Frog-Leg Winding Permanent-Magnet DC Machine

    Directory of Open Access Journals (Sweden)

    Hang Zhang

    2014-03-01

    Full Text Available An electric commutated frog-leg winding permanent-magnet (PM DC machine is proposed in this paper. It has a semi-closed slotted stator with a classical type of mesh winding introduced from the conventional brushed DC machine and a polyphase electric commutation besides a PM excitation rotor and a circular arrayed Hall position sensor. Under the cooperation between the position sensor and the electric commutation, the proposed machine is basically operated on the same principle of the brushed one. Because of its simplex frog-leg winding, the combination between poles and slots is designed as 4/22, and the number of phases is set as 11. By applying an exact analytical method, which is verified comparable with the finite element analyses (FEA, to the prediction of its instantaneous magnetic field, electromotive force (EMF, cogging torque and output torque, it is well designed with a series of parameters in dimension aiming at the lowest cogging torque. A 230 W, 4-pole, and 22-slot new machine is prototyped and tested to verify the analysis.

  6. The Art and Science of Polymer Brushes: Recent Developments in Patterning and Characterization Approaches.

    Science.gov (United States)

    Panzarasa, Guido

    2017-06-28

    Polymer brushes are dense arrays of macromolecular chains tethered by one end at a surface. They are at the cutting edge of polymer nanotechnology since the dawn of controlled surface-initiated polymerization techniques unlocked new prospects for the synthesis of polymer brushes with tailorable properties. More recently, thanks to the growing interest in the use of brushes for the generation of functional surfaces, the need for advanced patterning and characterization approaches rapidly increased. Meeting these needs requires the contribution of experts from different disciplines: polymer chemistry, surface science, electrochemistry and particle physics. The focus of this review is to highlight recent developments in the field of polymer brushes, specifically the application of photocatalytic lithography as a versatile patterning strategy, the study of grafted-from polymer brushes by electrochemical methods and, most importantly, the introduction of positron annihilation spectroscopy as a powerful technique for the investigation of the structure of polymer brushes and of their composites with nanoparticles.

  7. Brushing abrasion of dentin: effect of diluent and dilution rate of toothpaste.

    Science.gov (United States)

    Turssi, Cecilia P; Messias, Danielle C F; Hara, Anderson Takeo; Hughes, Nathan; Garcia-Godoy, Franklin

    2010-10-01

    To determine whether toothpaste diluent type and dilution rate influence abrasion of dentin. Slabs of human root dentin (4 x 3 x 2 mm) were embedded in epoxy resin, ground and polished. Adhesive tape was placed on the specimen's surface leaving an exposed central area of 1 x 4 mm. Specimens (n = 15) were then brushed for 1,000 strokes in a reciprocal action brushing simulator using toothpaste that had been diluted in a carboxymethylcellulose-based artificial saliva (CMC) or deionized water (DW) from 1:1 to 1:4 (toothpaste:diluents, in weight). Control groups were brushed with undiluted toothpaste, CMC-based saliva or DW only. Brushing simulation was run at 300 g load at 37 degrees C. After brushing, adhesive tape was removed and wear analyzed by optical profilometry. One-way ANOVA (P diluent. Brushing with CMC- or DW-only caused the least abrasion.

  8. Atmel Microcontroller Based Soft Switched PWM ZVS Full Bridge DC to DC Converter

    Directory of Open Access Journals (Sweden)

    DEEPAK KUMAR NAYAK

    2010-12-01

    Full Text Available This paper deals with the simulation and implementation of soft switched PWM ZVS full bridge DC to DC converter. The 48V DC is efficiently reduced to 12V DC using a DC to DC converter. This converter has advantages like reduced switching losses, stresses and EMI. Input DC is converted into high frequency AC and it is stepped down to 12V level. Later it is rectified using a full wave rectifier. Laboratory model of microcontroller based DC to DC converter is fabricated and tested. The experimental results are compared with the simulation results.

  9. SIMULATION AND IMPLEMENTATION OF PID-ANN CONTROLLER FOR CHOPPER FED EMBEDDED PMDC MOTOR

    Directory of Open Access Journals (Sweden)

    M. Madheswaran

    2012-04-01

    Full Text Available The closed loop control of PMDC drive with an inner current controller and an outer PID-ANN (Proportional Integral Derivative – Artificial Neural Network based speed controller is designed and presented in this paper. Motor is fed by DC / DC buck converter (DC Chopper. The controller is used to change the duty cycle of the converter and thereby, the voltage fed to the PMDC motor to regulate the speed. The PID-ANN controller designed was evaluated by computer simulation and it was implemented using an 8051 based embedded system. This system will operate in forward motoring with variable speed.

  10. Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system.

    Science.gov (United States)

    Lillaney, Prasheel; Shin, Mihye; Hinshaw, Waldo; Bennett, N Robert; Pelc, Norbert; Fahrig, Rebecca

    2013-02-01

    Using hybrid x-ray∕MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also evaluated to determine

  11. Simulation and modelling of slip flow over surfaces grafted with polymer brushes and glycocalyx fibres

    OpenAIRE

    Deng, Mingge; Li, Xuejin; Liang, Haojun; Caswell, Bruce; Karniadakis, George Em

    2012-01-01

    Fabrication of functionalized surfaces using polymer brushes is a relatively simple process and parallels the presence of glycocalyx filaments coating the luminal surface of our vasculature. In this paper, we perform atomistic-like simulations based on dissipative particle dynamics (DPD) to study both polymer brushes and glycocalyx filaments subject to shear flow, and we apply mean-field theory to extract useful scaling arguments on their response. For polymer brushes, a weak shear flow has n...

  12. Tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students

    Directory of Open Access Journals (Sweden)

    Clement C. Azodo

    2010-08-01

    Full Text Available Objective: To determine the tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students. Methods: A descriptive cross-sectional study of students of Federal School of Dental Therapy and Technology Enugu, Nigeria. Self-administered questionnaire was used to obtain information on demography, frequency, duration and technique of tooth brushing and tongue cleaning as well as information on consumption of snacks. Results: A total of 242 students responded. Dental technology students made up 52.5% of the respondents and dental therapist in training made up 47.5%. Majority (63.2% of the respondents considered the strength of tooth brush when purchasing a tooth brush and 78.9% use tooth brushes with medium strength. Seven-tenth (71.9% of the respondents brush their teeth twice daily and 52.1% brush for 3–5 minutes. About one-third (30.2% brush their teeth in front of a mirror. Chewing stick was used by 51.7% of respondents in addition to the use of tooth brush. Tongue cleaning was done by 94.2% with only 9.5% using a tongue cleaner. Only 20.2% reported regular snacks consumption. Nine-tenth (90.4% of respondents were previously involved in educating others, apart from their colleagues, on tooth brushing. Conclusion: This survey revealed that most of the dental therapy and technology students had satisfactory tooth-brushing behaviour. The zeal to educate others about proper tooth brushing revealed in this study suggests that the students may be helpful in oral health promotion.

  13. Comparison between observed children's tooth brushing habits and those reported by mothers.

    Science.gov (United States)

    Martins, Carolina C; Oliveira, Maria J; Pordeus, Isabela A; Paiva, Saul M

    2011-09-03

    Information bias can occur in epidemiological studies and compromise scientific outcomes, especially when evaluating information given by a patient regarding their own health. The oral habits of children reported by their mothers are commonly used to evaluate tooth brushing practices and to estimate fluoride intake by children. The aim of the present study was to compare observed tooth-brushing habits of young children using fluoridated toothpaste with those reported by mothers. A sample of 201 mothers and their children (aged 24-48 months) from Montes Claros, Brazil, took part in a cross-sectional study. At day-care centres, the mothers answered a self-administered questionnaire on their child's tooth-brushing habits. The structured questionnaire had six items with two to three possible answers. An appointment was then made with each mother/child pair at day-care centres. The participants were asked to demonstrate the tooth-brushing practice as usually performed at home. A trained examiner observed and documented the procedure. Observed tooth brushing and that reported by mothers were compared for overall agreement using Cohen's Kappa coefficient and the McNemar test. Cohen's Kappa values comparing mothers' reports and tooth brushing observed by the examiner ranged from poor-to-good (0.00-0.75). There were statistically significant differences between observed tooth brushing habits and those reported by mothers (p brushed their teeth alone (33.8%) and those who did not rinse their mouths during brushing (42.0%) were higher than those reported by the mothers (12.1%, 18.9% and 6.5%, respectively; p brushing and mothers' reports. Moreover, the different methods of estimation resulted in differences in the frequencies of tooth brushing habits, indicative of reporting bias. Data regarding children's tooth-brushing habits as reported by mothers should be considered with caution in epidemiological surveys on fluoridated dentifrice use and the risk of dental fluorosis.

  14. An Experimental-Theoretical Analysis of Protein Adsorption on Peptidomimetic Polymer Brushes

    OpenAIRE

    Lau, K. H. Aaron; Ren, Chunlai; Park, Sung Hyun; Szleifer, Igal; Messersmith, Phillip B.

    2011-01-01

    Surface-grafted water soluble polymer brushes are being intensely investigated for preventing protein adsorption to improve biomedical device function, prevent marine fouling, and enable applications in biosensing and tissue engineering. In this contribution, we present an experimental-theoretical analysis of a peptidomimetic polymer brush system with regard to the critical brush density required for preventing protein adsorption at varying chain lengths. A mussel adhesive-inspired DOPA-Lys p...

  15. Tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students.

    Science.gov (United States)

    Azodo, Clement C; Ehizele, Adebola O; Umoh, Agnes; Ojehanon, Patrick I; Akhionbare, Osagie; Okechukwu, Robinson; Igbinosa, Lawrence

    2010-08-12

    To determine the tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students. A descriptive cross-sectional study of students of Federal School of Dental Therapy and Technology Enugu, Nigeria. Self-administered questionnaire was used to obtain information on demography, frequency, duration and technique of tooth brushing and tongue cleaning as well as information on consumption of snacks. A total of 242 students responded. Dental technology students made up 52.5% of the respondents and dental therapist in training made up 47.5%. Majority (63.2%) of the respondents considered the strength of tooth brush when purchasing a tooth brush and 78.9% use tooth brushes with medium strength. Seven-tenth (71.9%) of the respondents brush their teeth twice daily and 52.1% brush for 3-5 minutes. About one-third (30.2%) brush their teeth in front of a mirror. Chewing stick was used by 51.7% of respondents in addition to the use of tooth brush. Tongue cleaning was done by 94.2% with only 9.5% using a tongue cleaner. Only 20.2% reported regular snacks consumption. Nine-tenth (90.4%) of respondents were previously involved in educating others, apart from their colleagues, on tooth brushing. This survey revealed that most of the dental therapy and technology students had satisfactory tooth-brushing behaviour. The zeal to educate others about proper tooth brushing revealed in this study suggests that the students may be helpful in oral health promotion.

  16. High performance stepper motors for space mechanisms

    Science.gov (United States)

    Sega, Patrick; Estevenon, Christine

    1995-01-01

    Hybrid stepper motors are very well adapted to high performance space mechanisms. They are very simple to operate and are often used for accurate positioning and for smooth rotations. In order to fulfill these requirements, the motor torque, its harmonic content, and the magnetic parasitic torque have to be properly designed. Only finite element computations can provide enough accuracy to determine the toothed structures' magnetic permeance, whose derivative function leads to the torque. It is then possible to design motors with a maximum torque capability or with the most reduced torque harmonic content (less than 3 percent of fundamental). These later motors are dedicated to applications where a microstep or a synchronous mode is selected for minimal dynamic disturbances. In every case, the capability to convert electrical power into torque is much higher than on DC brushless motors.

  17. Very High Frequency Half Bridge DC/DC Converter

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    This paper presents the first, off chip, class DE (resonant half bridge) converter working in the Very High Frequency (VHF) range. The benefits of using half bridge circuits both in the inverter and rectifier part of a VHF resonant dc/dc converter are analyzed and design equations for all...... components in the power stage are given. The circuit has been simulated to verify the accuracy of the presented equations and an efficiency of 89% has been shown. A prototype has been implemented with self-oscillating resonant gate drives driving the switches. The prototype has been used to drive an LED...

  18. A SOFT SWITCHED INTERLEAVED HIGH GAIN DC-DC CONVERTER

    Directory of Open Access Journals (Sweden)

    SHESHIDHAR REDDY ADDULA

    2017-09-01

    Full Text Available In this paper, a novel soft-switched interleaved DC-DC converter which provides a high voltage gain of 12 is proposed. Voltage gain of the basic interleaved boost converter is extended by using diode-capacitor multiplier (DCM cells. The switches are operated at a nominal duty ratio of 0.5. The voltage stress on the power switches and diodes is only a fraction of the output voltage. To enhance the operating power conversion efficiency, the switches are turned ON at zero voltage condition. Experimental results of 18-216V, 100W prototype converter validate the operating principle and the advantageous features of the presented converter.

  19. Power flow analysis for DC voltage droop controlled DC microgrids

    DEFF Research Database (Denmark)

    Li, Chendan; Chaudhary, Sanjay; Dragicevic, Tomislav

    2014-01-01

    This paper proposes a new algorithm for power flow analysis in droop controlled DC microgrids. By considering the droop control in the power flow analysis for the DC microgrid, when compared with traditional methods, more accurate analysis results can be obtained. The algorithm verification...... is carried out by comparing the calculation results with detailed time domain simulation results. With the droop parameters as variables in the power flow analysis, their effects on power sharing and secondary voltage regulation can now be analytically studied, and specialized optimization in the upper level...... control can also be made accordingly. Case studies on power sharing and secondary voltage regulation are carried out using proposed power flow analysis....

  20. Pulse-width modulated DC-DC power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2008-01-01

    This book studies switch-mode power supplies (SMPS) in great detail. This type of converter changes an unregulated DC voltage into a high-frequency pulse-width modulated (PWM) voltage controlled by varying the duty cycle, then changes the PWM AC voltage to a regulated DC voltage at a high efficiency by rectification and filtering. Used to supply electronic circuits, this converter saves energy and space in the overall system. With concept-orientated explanations, this book offers state-of-the-art SMPS technology and promotes an understanding of the principle operations of PWM converters,

  1. Light-weight DC to very high voltage DC converter

    Science.gov (United States)

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  2. DC grid for home applications

    Science.gov (United States)

    Elangovan, D.; Archana, R.; Jayadeep, V. J.; Nithin, M.; Arunkumar, G.

    2017-11-01

    More than fifty percent Indian population do not have access to electricity in daily lives. The distance between the power generating stations and the distribution centers forms one of the main reasons for lack of electrification in rural and remote areas. Here lies the importance of decentralization of power generation through renewable energy resources. In the present world, electricity is predominantly powered by alternating current, but most day to day devices like LED lamps, computers and electrical vehicles, all run on DC power. By directly supplying DC to these loads, the number of power conversion stages was reduced, and overall system efficiency increases. Replacing existing AC network with DC is a humongous task, but with power electronic techniques, this project intends to implement DC grid at a household level in remote and rural areas. Proposed work was designed and simulated successfully for various loads amounting to 250 W through appropriate power electronic convertors. Maximum utilization of the renewable sources for domestic and commercial application was achieved with the proposed DC topology.

  3. Analysis of carbon fiber brush loading in anodes on startup and performance of microbial fuel cells

    KAUST Repository

    Hutchinson, Adam J.

    2011-11-01

    Flat carbon anodes placed near a cathode in a microbial fuel cell (MFC) are adversely affected by oxygen crossover, but graphite fiber brush anodes placed near the cathode produce high power densities. The impact of the brush size and electrode spacing was examined by varying the distance of the brush end from the cathode and solution conductivity in multiple MFCs. The startup time was increased from 8 ± 1 days with full brushes (all buffer concentrations) to 13 days (50 mM), 14 days (25 mM) and 21 days (8 mM) when 75% of the brush anode was removed. When MFCs were all first acclimated with a full brush, up to 65% of the brush material could be removed without appreciably altering maximum power. Electrochemical impedance spectroscopy (EIS) showed that the main source of internal resistance (IR) was diffusion resistance, which together with solution resistance reached 100 Ω. The IR using EIS compared well with that obtained using the polarization data slope method, indicating no major components of IR were missed. These results show that using full brush anodes avoids adverse effects of oxygen crossover during startup, although brushes are much larger than needed to sustain high power. © 2011 Elsevier B.V.

  4. Comparison of the transport characteristics of ceftibuten in rat renal and intestinal brush-border membranes.

    Science.gov (United States)

    Naasani, I; Sato, K; Iseki, K; Sugawara, M; Kobayashi, M; Miyazaki, K

    1995-09-12

    The transport characteristics of ceftibuten, a dianionic cephem antibiotic, in rat renal and intestinal brush-border membranes were compared. Ceftibuten transport was mediated by two transport systems in the renal brush-border membrane and by one transport system in the intestinal brush-border membrane. The apparent kinetic parameters for the uptake of ceftibuten by the renal brush-border membrane vesicles, respectively, were: Km1, Km2 values of 26 and 1946 microM and Vmax1, Vmax2 values of 105 and 1400 pmol/mg protein per 30 s. The apparent kinetic parameters for the uptake by the intestinal brush-border membrane vesicles were: Km of 425 microM and Vmax of 1701 pmol/mg protein per 30 s. In the renal brush-border membrane, L-Ala-L-Pro was partially competitive and competitive inhibitor for the uptake by the high and low affinity systems, respectively. However, L-Ala-L-Pro was a non-competitive inhibitor for the uptake by the intestinal brush-border membrane vesicles. L-Carnosine was a specific and competitive inhibitor for the high affinity system in the renal brush-border membrane, while it had no effect on the low affinity system of the kidney or on the transport system of the intestine. It was concluded that the transport characteristics of ceftibuten in the renal and intestinal brush-border membranes are similar in some aspects but they are not identical.

  5. Behavioral determinants of brushing young children's teeth: implications for anticipatory guidance.

    Science.gov (United States)

    Huebner, Colleen E; Riedy, Christine A

    2010-01-01

    The purposes of this study were to identify parents' motivation, support, and barriers to twice daily tooth-brushing of infants and preschool-age children and to discover new approaches to encourage this important health behavior. Qualitative interviews were conducted with 44 rural parents about tooth-brushing habits and experiences. Forty of 44 parents reported that they had begun to brush their child's teeth; 24 (55%) reported brushing twice a day or more. Parents who brushed twice a day, vs less often, were more likely to describe specific skills to overcome barriers; they expressed high self-efficacy and held high self-standards for brushing. Parents who brushed their children's teeth less than twice daily were more likely to: hold false beliefs about the benefits of twice daily tooth-brushing; report little normative pressure or social support for the behavior; have lower self-standards; describe more external constraints; and offer fewer ideas to overcome barriers. The findings support an integrative framework in which barriers and support for parents' twice daily brushing of their young children's teeth are multiple and vary among individuals. Knowledge of behavioral determinants specific to individual parents could strengthen anticipatory guidance and recommendations about at-home oral hygiene of young children.

  6. Behavioral Determinants of Brushing Young Children's Teeth: Implications for Anticipatory Guidance

    Science.gov (United States)

    Huebner, Colleen E.; Riedy, Christine A.

    2010-01-01

    Purpose The purposes of this study were to identify parents' motivation, support, and barriers to twice daily tooth-brushing of infants and preschool-age children and to discover new approaches to encourage this important health behavior. Methods Qualitative interviews were conducted with 44 rural parents about tooth-brushing habits and experiences. Results Forty of 44 parents reported that they had begun to brush their child's teeth; 24 (55%) reported brushing twice a day or more. Parents who brushed twice a day, vs less often, were more likely to describe specific skills to overcome barriers; they expressed high self-efficacy and held high self-standards for brushing. Parents who brushed their children's teeth less than twice daily were more likely to: hold false beliefs about the benefits of twice daily tooth-brushing; report little normative pressure or social support for the behavior; have lower self-standards; describe more external constraints; and offer fewer ideas to overcome barriers. Conclusions The findings support an integrative framework in which barriers and support for parents' twice daily brushing of their young children's teeth are multiple and vary among individuals. Knowledge of behavioral determinants specific to individual parents could strengthen anticipatory guidance and recommendations about at-home oral hygiene of young children. PMID:20298653

  7. An experimental-theoretical analysis of protein adsorption on peptidomimetic polymer brushes.

    Science.gov (United States)

    Lau, K H Aaron; Ren, Chunlai; Park, Sung Hyun; Szleifer, Igal; Messersmith, Phillip B

    2012-01-31

    Surface-grafted water-soluble polymer brushes are being intensely investigated for preventing protein adsorption to improve biomedical device function, prevent marine fouling, and enable applications in biosensing and tissue engineering. In this contribution, we present an experimental-theoretical analysis of a peptidomimetic polymer brush system with regard to the critical brush density required for preventing protein adsorption at varying chain lengths. A mussel adhesive-inspired DOPA-Lys (DOPA = 3,4-dihydroxy-phenylalanine; Lys = lysine) pentapeptide surface grafting motif enabled aqueous deposition of our peptidomimetic polypeptoid brushes over a wide range of chain densities. Critical densities of 0.88 nm(-2) for a relatively short polypeptoid 10-mer to 0.42 nm(-2) for a 50-mer were identified from measurements of protein adsorption. The experiments were also compared with the protein adsorption isotherms predicted by a molecular theory. Excellent agreements in terms of both the polymer brush structure and the critical chain density were obtained. Furthermore, atomic force microscopy (AFM) imaging is shown to be useful in verifying the critical brush density for preventing protein adsorption. The present coanalysis of experimental and theoretical results demonstrates the significance of characterizing the critical brush density in evaluating the performance of an antifouling polymer brush system. The high fidelity of the agreement between the experiments and molecular theory also indicate that the theoretical approach presented can aid in the practical design of antifouling polymer brush systems. © 2011 American Chemical Society

  8. Oral hygiene management of autistic population -an investigation of their tooth brushing-

    OpenAIRE

    田邊, 義浩; 石倉, 優香; 野田, 忠; Tanabe, Yoshihiro; Ishikura, Yuuka; Noda, Tadashi

    1996-01-01

    The purpose of this study was to know the factors influencing on tooth brushing of autistic population. The subjects were 17 utistic patients who commuted to a welfare institution in Niigata city, aged from 16 to 27 years old. The parents of the subjects were asked to answer a questionnaire about the way of tooth brushing in their family life. The subjects were tested for their understanding about the mean of tooth brushing by some series of picture cards of oral health, tooth brushing and de...

  9. Contaminated tooth brushes-potential threat to oral and general health.

    Science.gov (United States)

    Naik, Rashmi; Ahmed Mujib, B R; Telagi, Neethu; Anil, B S; Spoorthi, B R

    2015-01-01

    Tooth brushing is most common method of maintaining oral hygiene. In removing plaque and other soft debris from the teeth, tooth brushes become contaminated with bacteria, blood, saliva and oral debris. These contaminated tooth brushes can be a source of infection. The aim of the present study was to evaluate the presence of microorganisms in the tooth brushes and to investigate the effect of disinfectants such as chlorhexidine gluconate, sodium hypochlorite and water to decontaminate them. Twenty-one children were asked to brush their teeth for 5 days with a tooth brush. The tooth brushes were put in Robertson's Cooked Meat broth and were observed for growth of Streptococcal microorganisms. These tooth brushes were then placed in disinfectants such as 0.2% chlorhexidine gluconate (Group I), 1% sodium hypochlorite (Group II) and water (Group III) for 24 hrs and then cultured again. Reduction of growth of microorganisms was seen in Group I, Group II and remnants of growth seen in Group III. We conclude that the use of disinfectant for a tooth brush is a must for every individual at least at regular intervals.

  10. Contaminated tooth brushes-potential threat to oral and general health

    Directory of Open Access Journals (Sweden)

    Rashmi Naik

    2015-01-01

    Full Text Available Background: Tooth brushing is most common method of maintaining oral hygiene. In removing plaque and other soft debris from the teeth, tooth brushes become contaminated with bacteria, blood, saliva and oral debris. These contaminated tooth brushes can be a source of infection. Aims and objectives: The aim of the present study was to evaluate the presence of microorganisms in the tooth brushes and to investigate the effect of disinfectants such as chlorhexidine gluconate, sodium hypochlorite and water to decontaminate them. Materials and Methods: Twenty-one children were asked to brush their teeth for 5 days with a tooth brush. The tooth brushes were put in Robertson′s Cooked Meat broth and were observed for growth of Streptococcal microorganisms. These tooth brushes were then placed in disinfectants such as 0.2% chlorhexidine gluconate (Group I, 1% sodium hypochlorite (Group II and water (Group III for 24 hrs and then cultured again. Reduction of growth of microorganisms was seen in Group I, Group II and remnants of growth seen in Group III. Conclusion: We conclude that the use of disinfectant for a tooth brush is a must for every individual at least at regular intervals.

  11. Stepper motor

    Science.gov (United States)

    Dekramer, Cornelis

    1994-01-01

    The purpose of this document is to describe the more commonly used permanent magnet stepper motors for spaceflight. It will discuss the mechanical and electrical aspects of the devices, their torque behavior, those parameters which need to be controlled and measured, and test methods to be employed. It will also discuss torque margins, compare these to the existing margin requirements, and determine the applicability of these requirements. Finally it will attempt to generate a set of requirements which will be used in any stepper motor procurement and will fully characterize the stepper motor behavior in a consistent and repeatable fashion.

  12. Linking DC together with TRSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne; Yong, Xia

    1999-01-01

    for high-level specifications of real-time requirementsand TRSL for specifying real-time implementations in the form of timed communicating concurrent processes.In order to link DC and TRSL together in a well-founded way, we formally define what it means for a TRSL process to satisfy a DC requirement...... of constraints on the durations of states of the system, i.e. at a high level of abstraction.However, as a state-based logic, it lacks the ability to specifysequential programs and communicating concurrent processes at a concrete level. The Timed RAISE Specification Language (TRSL) [XG99] has this ability.......TRSL is a real-time extension of the RAISE Specification Language (RSL) [Rlg92] which together with its associated method [Rmg95]and tools has shown to be very useful in the industrial development of software systems. Therefore, a promising approach for the development of real-time systemscould be to use DC...

  13. Variable frequency inverter for ac induction motors with torque, speed and braking control

    Science.gov (United States)

    Nola, F. J. (Inventor)

    1975-01-01

    A variable frequency inverter was designed for driving an ac induction motor which varies the frequency and voltage to the motor windings in response to varying torque requirements for the motor so that the applied voltage amplitude and frequency are of optimal value for any motor load and speed requirement. The slip frequency of the motor is caused to vary proportionally to the torque and feedback is provided so that the most efficient operating voltage is applied to the motor. Winding current surge is limited and a controlled negative slip causes motor braking and return of load energy to a dc power source.

  14. Efficacy of oral brush biopsy in potentially malignant disorder management.

    Science.gov (United States)

    Goodson, M L; Smith, D R; Thomson, P J

    2017-11-01

    Oral potentially malignant disorders (PMD) harbour unpredictable risk for squamous cell carcinoma development. Current management requires tissue biopsy for histopathology characterisation, dysplasia grading and targeted intervention to "high-risk" lesions, although evidence-based guidelines are limited and diagnoses subjective. This study investigated the use of adjunctive oral brush biopsy techniques during the management of PMD in a UK hospital population. Retrospective review of a 310 PMD patient cohort presenting to Maxillofacial Surgery in Newcastle upon Tyne with new, single-site lesions between December 2009 and May 2014. Patients underwent Orcellex® brush biopsy and liquid-based cytology examination in addition to conventional biopsy techniques, with management proceeding along established care pathways. Patient demographics, cytology data, most significant histopathology diagnoses and clinical outcome were all documented at the study census date (31.12.15). A total of 170 male & 140 female patients (age range 18-91 years), exhibiting primarily leukoplakia (86.5%) at floor of mouth and ventrolateral tongue sites (44.9%), were identified. Management comprised: observation (49.7%), laser surgery (44.9%), antifungal treatment (3.5%) and Head & Neck clinic referral following cancer diagnosis (1.9%). Clinical outcomes were as follows: disease free (51.3%), persistent PMD (42.3%) and malignant transformation (6.4%). Histology and cytology diagnoses strongly correlated (r = .305). Treatment modality, lesion site, histology and cytology diagnoses were the best predictors of clinical outcome. Orcellex® brush cytology provides reliable diagnoses consistent with conventional histopathology and offers less invasive, adjunctive assessment appropriate for long-term monitoring of patients in specialist clinics. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. A Modified Tactile Brush Algorithm for Complex Touch Gestures

    Energy Technology Data Exchange (ETDEWEB)

    Ragan, Eric [Texas A& M University

    2015-01-01

    Several researchers have investigated phantom tactile sensation (i.e., the perception of a nonexistent actuator between two real actuators) and apparent tactile motion (i.e., the perception of a moving actuator due to time delays between onsets of multiple actuations). Prior work has focused primarily on determining appropriate Durations of Stimulation (DOS) and Stimulus Onset Asynchronies (SOA) for simple touch gestures, such as a single finger stroke. To expand upon this knowledge, we investigated complex touch gestures involving multiple, simultaneous points of contact, such as a whole hand touching the arm. To implement complex touch gestures, we modified the Tactile Brush algorithm to support rectangular areas of tactile stimulation.

  16. Galectin-4 and small intestinal brush border enzymes form clusters

    DEFF Research Database (Denmark)

    Danielsen, E M; van Deurs, B

    1997-01-01

    to galectin-4 to coimmunoprecipitate aminopeptidase N and sucrase-isomaltase. Furthermore, galectin-4 was released from microvillar, right-side-out vesicles as well as from mucosal explants by a brief wash with 100 mM lactose, confirming its extracellular localization. Galectin-4 is therefore secreted...... that galectin-4 is indeed an intestinal brush border protein; we also localized galectin-4 throughout the cell, mainly associated with membraneous structures, including small vesicles, and to the rootlets of microvillar actin filaments. This was confirmed by subcellular fractionation, showing about half...

  17. Foundations of DC plasma sources

    Science.gov (United States)

    Tomas Gudmundsson, Jon; Hecimovic, Ante

    2017-12-01

    A typical dc discharge is configured with the negative cathode at one end and a positive anode at the other end, separated by a gas filled gap, placed inside a long glass cylinder. A few hundred volts between the cathode and anode is required to maintain the discharge. The type of discharge that is formed between the two electrodes depends upon the pressure of the working gas, the nature of the working gas, the applied voltage and the geometry of the discharge. We discuss the current–voltage characteristics of the discharge as well as the distinct structure that develops in the glow discharge region. The dc glow discharge appears in the discharge current range from μA to mA at 0.5–300 Pa pressure. We discuss the various phenomena observed in the dc glow discharge, including the cathode region, the positive column, and striations. The dc glow discharge is maintained by the emission of secondary electrons from the cathode target due to the bombardment of ions. For decades, the dc glow discharge has been used as a sputter source. Then it is often operated as an obstructed abnormal glow discharge and the required applied voltage is in the range 2–5 kV. Typically, the cathode target (the material to be deposited) is connected to a negative voltage supply (dc or rf) and the substrate holder faces the target. The relatively high operating pressure, in the range from 2 to 4 Pa, high applied voltages, and the necessity to have a conductive target limit the application of dc glow discharge as a sputter source. In order to lower the discharge voltage and expand the operation pressure range, the lifetime of the electrons in target vicinity is increased through applying magnetic field, by adding permanent magnets behind the cathode target. This arrangement is coined the magnetron sputtering discharge. The various configurations of the magnetron sputtering discharge and its applications are described. Furthermore, the use of dc discharges for chemical analysis, the

  18. Modeling and analysis of fractional order DC-DC converter.

    Science.gov (United States)

    Radwan, Ahmed G; Emira, Ahmed A; AbdelAty, Amr M; Azar, Ahmed Taher

    2017-07-11

    Due to the non-idealities of commercial inductors, the demand for a better model that accurately describe their dynamic response is elevated. So, the fractional order models of Buck, Boost and Buck-Boost DC-DC converters are presented in this paper. The detailed analysis is made for the two most common modes of converter operation: Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM). Closed form time domain expressions are derived for inductor currents, voltage gain, average current, conduction time and power efficiency where the effect of the fractional order inductor is found to be strongly present. For example, the peak inductor current at steady state increases with decreasing the inductor order. Advanced Design Systems (ADS) circuit simulations are used to verify the derived formulas, where the fractional order inductor is simulated using Valsa Constant Phase Element (CPE) approximation and Generalized Impedance Converter (GIC). Different simulation results are introduced with good matching to the theoretical formulas for the three DC-DC converter topologies under different fractional orders. A comprehensive comparison with the recently published literature is presented to show the advantages and disadvantages of each approach. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    Science.gov (United States)

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  20. Control of AC–DC grid side converter with single AC current sensor

    Indian Academy of Sciences (India)

    Himanshu Misra

    2017-11-24

    Nov 24, 2017 ... Grid side converter; vector control; single current sensor; AC–DC conversion. 1. Introduction. Three-phase ... of sensors in any closed loop control. This will lead to primarily two main advantages: cost ... induction motor control was presented by Verma and group in [15]. In this paper, extended work of [14] is ...

  1. Plaque-removing efficacy of new and used manual toothbrushes--a professional brushing study.

    Science.gov (United States)

    Rosema, N A M; Hennequin-Hoenderdos, N L; Versteeg, P A; van Palenstein Helderman, W H; van der Velden, U; van der Weijden, G A

    2013-11-01

    The present study assessed whether 3-month-old used manual toothbrushes are less effective in reducing plaque scores compared with new toothbrushes with or without the use of dentifrice. The present study was performed employing a single-use, examiner-blinded, professional brushing model. Four brushing modalities were randomly allocated to one of four quadrants, that is, 3-month-old used toothbrushes and new toothbrushes both with and without the use of dentifrice. Prebrushing and post-brushing plaque scores (Quigley Hein plaque index) and gingival abrasion (GA) scores were obtained. A dental hygienist performed the professional brushing procedure. The 3-month-old used toothbrushes were assessed for wear. No significant differences were observed among the treatments with regard to the prebrushing scores. The post-brushing plaque scores ranged from 1.59 for the new brush with dentifrice to 1.76 for the old brush with dentifrice. There was a significant difference (P = 0.036) among the four treatments regarding the old brush with dentifrice, which removed less plaque than the other treatment modalities. Regarding GA scores, no significant differences were observed. With regard to toothbrush wear after 3 months of use, the scores varied widely among the individually evaluated brushes. The present study did not show a clinically relevant difference in plaque score reductions following a 2-minute brushing exercise among 3-month-old used and new manual toothbrushes. However, the wear rate of the brushes seemed to be the determining factor in loss of efficacy, rather than the age of the toothbrush. Furthermore, dentifrice did not show an additional effect on instant plaque removal. © 2013 John Wiley & Sons A/S.

  2. Brushing force of manual and sonic toothbrushes affects dental hard tissue abrasion.

    Science.gov (United States)

    Wiegand, Annette; Burkhard, John Patrik Matthias; Eggmann, Florin; Attin, Thomas

    2013-04-01

    This study aimed to determine the brushing forces applied during in vivo toothbrushing with manual and sonic toothbrushes and to analyse the effect of these brushing forces on abrasion of sound and eroded enamel and dentin in vitro. Brushing forces of a manual and two sonic toothbrushes (low and high frequency mode) were measured in 27 adults before and after instruction of the respective brushing technique and statistically analysed by repeated measures analysis of variance (ANOVA). In the in vitro experiment, sound and eroded enamel and dentin specimens (each subgroup n = 12) were brushed in an automatic brushing machine with the respective brushing forces using a fluoridated toothpaste slurry. Abrasion was determined by profilometry and statistically analysed by one-way ANOVA. Average brushing force of the manual toothbrush (1.6 ± 0.3 N) was significantly higher than for the sonic toothbrushes (0.9 ± 0.2 N), which were not significantly different from each other. Brushing force prior and after instruction of the brushing technique was not significantly different. The manual toothbrush caused highest abrasion of sound and eroded dentin, but lowest on sound enamel. No significant differences were detected on eroded enamel. Brushing forces of manual and sonic toothbrushes are different and affect their abrasive capacity. Patients with severe tooth wear and exposed and/or eroded dentin surfaces should use sonic toothbrushes to reduce abrasion, while patients without tooth wear or with erosive lesions confining only to enamel do not benefit from sonic toothbrushes with regard to abrasion.

  3. Efficacy of straight versus angled interdental brushes on interproximal tooth cleaning: a randomized controlled trial.

    Science.gov (United States)

    Jordan, R A; Hong, H M; Lucaciu, A; Zimmer, S

    2014-05-01

    To investigate interproximal biofilm reduction with an angled interdental brush as compared to a straight interdental brush (standard control) in a clinical, single-centre, single-blind, controlled, parallel-group trial. Recruitment and examinations of the subjects were performed at the Witten/Herdecke University School of Dental Medicine. 128 volunteers, aged 20-65 years, were recruited and stratified according to sex and age. Two groups with 64 subjects each used either straight (standard control) or angled (test group) handgripped interdental toothbrushes of the same bristle stiffness. After a 12-day home-care habituation period, participants received a professional tooth cleaning followed by a 48-h plaque regrowth period. At the intervention appointment, plaque was recorded with a fluorescent revelator and soft tissue damage was noted (T0 ). Interdental brushing was performed by the participant for 2 min, and clinical parameters were recorded again (T1 ). The primary efficacy end point was the difference in modified Proximal Plaque Index (mPPI) after brushing compared to baseline. Secondary efficacy end points were mPPI differences in subgroups (anterior vs. posterior teeth; vestibular vs. oral tooth surfaces). Safety end point was the Danser gingival abrasion index (DI). mPPI showed lower scores after brushing within all (sub)groups (P brushing efficacy (ΔT0  - T1 ) in subjects using straight interdental brushes was significantly higher as compared to angled interdental brushes (P brushes were significantly more effective in posterior teeth, when used from vestibular and from oral tooth surfaces (P teeth and concerning soft tissue damage. Straight interdental brushes may better remove plaque interproximally when compared to angled interdental brushes. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Tooth brushing motion patterns with manual and powered toothbrushes-a randomised video observation study.

    Science.gov (United States)

    Ganss, C; Duran, R; Winterfeld, T; Schlueter, N

    2018-03-01

    Systematic reviews have shown that powered toothbrushes (PTs) are more effective than manual toothbrushes (MTs), but with only minor effect sizes. Whether PTs are used adequately, however, has not been investigated so far. The aim of the present study was therefore to analyse motion habits with PT in comparison to MT toothbrushes by video observation. One hundred subjects were enrolled in this observational trial and brushed their teeth in randomised order with a MT and PT while being video-filmed, resulting in 95 analysable sets of recordings. Parameters of interest were brushing duration (s; median (min;max)), type of brushing strokes, area of brushing, changes between areas (n; median (min;max)) and brushing sequence. Brushing duration was 145 s (60;354) and 135 s (48;271) for PT and MT, respectively (p ≤ 0.001). Subjects brushed vestibular surfaces completely, but reached oral surfaces to a much lesser extent, regardless of the toothbrush type. With both toothbrushes, subjects moved frequently between areas (MT 35 (14;79); PT 33 (14;85); n.s.) and brushed predominantly with circling and horizontal strokes; with the PT, 50.5% of the subjects spent only brushing duration with passive brushing (positioning the brush head on the teeth with ≤2 movements/s). Intra-individual motion patterns were similar with both MT and PT, and most subjects persisted in their habitual motion patterns regardless of the toothbrush type. The use of PT and MT may need intensive training and supervision from oral hygiene educators in order to help subjects taking full advantage from these devices.

  5. Electric vehicle traction motors - The development of an advanced motor concept

    Science.gov (United States)

    Campbell, P.

    1980-01-01

    An axial-field permanent magnet traction motor is described, similar to several advanced motors that are being developed in the United States. This type of machine has several advantages over conventional dc motors, particularly in the electric vehicle application. The rapidly changing cost of magnetic materials, particularly cobalt, makes it important to study the utilization of permanent magnet materials in such machines. The impact of different magnets on machine design is evaluated, and the advantages of using iron powder composites in the armature are assessed.

  6. Scaling features of the tribology of polymer brushes of increasing grafting density around the mushroom-to-brush transition.

    Science.gov (United States)

    Mayoral, E; Klapp, J; Gama Goicochea, A

    2017-01-01

    Nonequilibrium coarse-grained, dissipative particle dynamics simulations of complex fluids, made up of polymer brushes tethered to planar surfaces immersed in a solvent yield nonmonotonic behavior of the friction coefficient as a function of the polymer grating density on the substrates, Γ, while the viscosity shows a monotonically increasing dependence on Γ. This effect is shown to be independent of the degree of polymerization, N, and the size of the system. It arises from the composition and the structure of the first particle layer adjacent to each surface that results from the confinement of the fluid. Whenever such layers are made up of as close a proportion of polymer beads to solvent particles as there are in the fluid, the friction coefficient shows a minimum, while for disparate proportions the friction coefficient grows. At the mushroom-to-brush transition (MBT) the viscosity scales with an exponent that depends on the characteristic exponent of the MBT (6/5) and the solvent quality exponent (ν=0.5, for θsolvent), but it is independent of the polymerization degree (N). On the other hand, the friction coefficient at the MBT scales as μ∼N^{6/5}, while the grafting density at the MBT scales as Γ∼N^{-6/5} when friction is minimal, in agreement with previous scaling theories. We argue these aspects are the result of cooperative phenomena that have important implications for the understanding of biological brushes and the design of microfluidics devices, among other applications of current academic and industrial interest.

  7. DC Microgrids—Part II

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Lu, Xiaonan; Quintero, Juan Carlos Vasquez

    2016-01-01

    . Closely coupled with protection, conflicting grounding objectives, e.g. minimization of stray current and common mode voltage are explained and several practical solutions are presented. Also, standardization efforts for DC systems are addressed. Finally, concluding remarks and important future research...

  8. Electricity-AC versus DC

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 10. Electricity - AC versus DC. D P Sen Gupta. General Article Volume 2 Issue 10 October 1997 pp 46-53. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/10/0046-0053. Author Affiliations.

  9. Voltage Weak DC Distribution Grids

    NARCIS (Netherlands)

    Hailu, T.G.; Mackay, L.J.; Ramirez Elizondo, L.M.; Ferreira, J.A.

    2017-01-01

    This paper describes the behavior of voltage weak DC distribution systems. These systems have relatively small system capacitance. The size of system capacitance, which stores energy, has a considerable effect on the value of fault currents, control complexity, and system reliability. A number of

  10. Graphene transistors with multifunctional polymer brushes for biosensing applications.

    Science.gov (United States)

    Hess, Lucas H; Lyuleeva, Alina; Blaschke, Benno M; Sachsenhauser, Matthias; Seifert, Max; Garrido, Jose A; Deubel, Frank

    2014-06-25

    Exhibiting a combination of exceptional structural and electronic properties, graphene has a great potential for the development of highly sensitive sensors. To date, many challenging chemical, biochemical, and biologic sensing tasks have been realized based on graphene. However, many of these sensors are rather unspecific. To overcome this problem, for instance, the sensor surface can be modified with analyte-specific transducers such as enzymes. One problem associated with the covalent attachment of such biomolecular systems is the introduction of crystal defects that have a deleterious impact on the electronic properties of the sensor. In this work, we present a versatile platform for biosensing applications based on polymer-modified CVD-grown graphene transistors. The functionalization method of graphene presented here allows one to integrate several functional groups within surface-bound polymer brushes without the introduction of additional defects. To demonstrate the potential of this polymer brush functionalization scaffold, we modified solution-gated graphene field-effect transistors with the enzyme acetylcholinesterase and a transducing group, allowing the detection of the neurotransmitter acetylcholine. Taking advantage of the transducing capability of graphene transistors and the versatility of polymer chemistry and enzyme biochemistry, this study presents a novel route for the fabrication of highly sensitive, multipurpose transistor sensors that can find application for a multitude of biologically relevant analytes.

  11. A novel music based tooth brushing system for blind children.

    Science.gov (United States)

    Shetty, V; Hegde, A M; Varghese, E; Shetty, V

    2013-01-01

    To assess the Oral Health Status (OHS) of visually impaired children in South India, to devise and implement a specially designed Oral Health Education (OHE) program for them and to assess its efficacy in improving their OHS. OHS of 98 institutionalized visually impaired children aged 6 to 14 years were evaluated at the start of the study (Pre-OHE level) using the Modified Gingival Index (MGI), the Turesky-Gilmore-Glickman modification of the Quigley Hein Plaque Index (MQHPI) and Streptococcus mutans colony count. Oral Health Education was imparted with the help of specially designed models and tooth-brushing taught with specially formulated music aided instructions in a song format. These parameters were re-evaluated after a period of reinforced (two weeks and one month) and non-reinforced (two months) tooth-brushing. Mean values of MGI and MQHPI showed a statistically very highly significant drop from the Pre-OHE level to the end of both the periods of reinforcement and non-reinforcement. There was a significant decrease in the S. mutans counts from the Pre-OHE levels to the period of non-reinforcement (p children was effective in improving their OHS significantly

  12. Rancang Bangun Graphical User Interface Untuk Pergerakan Motor Servo menggunakan Microsoft Visual Basic 2010 Express

    OpenAIRE

    Anggoro S Pramudyo

    2016-01-01

    Zaman sekarang ini teknologi sedang berkembang pesat dan robot-robot dirancang untuk dapat membantu pekerjaan dan tugas-tugas manusia. Motor servo merupakan salah satu jenis dari motor DC dan banyak diaplikasikan pada dunia robotik maupun peralatan lain, contohnya motor servo yang digunakan untuk robot berkaki. Dalam penggunaannya motor servo dapat bergerak karena ada sinyal yang dibangkitkan melalui sinyal PWM. Sinyal yang dihasilkan akan membentuk sudut sesuai nilai yang diberikan. Peneliti...

  13. Probing pH-responsive interactions between polymer brushes and hydrogels by neutron reflectivity.

    Science.gov (United States)

    Sudre, Guillaume; Hourdet, Dominique; Creton, Costantino; Cousin, Fabrice; Tran, Yvette

    2014-08-19

    We investigated the effect of specific interactions on the structure of interfaces between a brush and a hydrogel on the polymer chain length scale. We used a model system for which the interactions between the brush and the gel are switchable. We synthesized weak polyelectrolyte brushes of poly(acrylic acid) and hydrogels of polyacrylamide and poly(N,N-dimethylacrylamide) which interact solely when the poly(acrylic acid) is mainly in its acidic form. The monomer density profiles of the poly(acrylic acid) brush immersed in pure deuterium oxide (D2O) or in contact with a D2O-swollen gel were determined by neutron reflectivity. At pH 2 when the brush is in its neutral form, it interacts with the gel by hydrogen bonds while at pH 9 when the brush is a polyelectrolyte it is not interacting with the gel. Our results show that the presence of interactions with the gel at pH 2 increases the swelling ratio of the brush relative to that in pure D2O, meaning that the brushes exhibit conformations which are more extended from the surface than in the absence of interactions.

  14. A Low Cost Brush Deflection System for Bank Stabilization and Revegetation

    Science.gov (United States)

    Mary Elizabeth Meyer

    1989-01-01

    A series of brush deflectors were installed along an eroding, undercut streambank on Lindo Channel in Chico, California. Pieces of brush were wired to sets of metal fenceposts driven into the bank perpendicular to stream flow and at strategic points upstream. Dormant cuttings of riparian plants were added for revegetation and long-term bank protection. To date (two...

  15. Preparation and friction force microscopy measurements of immiscible, opposing polymer brushes

    NARCIS (Netherlands)

    de Beer, Sissi; Kutnyanszky, E.; Müser, M.H.; Vancso, Gyula J.

    2014-01-01

    Solvated polymer brushes are well known to lubricate high-pressure contacts, because they can sustain a positive normal load while maintaining low friction at the interface. Nevertheless, these systems can be sensitive to wear due to interdigitation of the opposing brushes. In a recent publication,

  16. Superhydrophilic polyelectrolyte brush layers with imparted anti-icing properties: effect of counter ions.

    Science.gov (United States)

    Chernyy, Sergey; Järn, Mikael; Shimizu, Kyoko; Swerin, Agne; Pedersen, Steen Uttrup; Daasbjerg, Kim; Makkonen, Lasse; Claesson, Per; Iruthayaraj, Joseph

    2014-05-14

    This work demonstrates the feasibility of superhydrophilic polyelectrolyte brush coatings for anti-icing applications. Five different types of ionic and nonionic polymer brush coatings of 25-100 nm thickness were formed on glass substrates using silane chemistry for surface premodification followed by polymerization via the SI-ATRP route. The cationic [2-(methacryloyloxy)ethyl]trimethylammonium chloride] and the anionic [poly(3-sulfopropyl methacrylate), poly(sodium methacrylate)] polyelectrolyte brushes were further exchanged with H+, Li+, Na+, K+, Ag+, Ca2+, La3+, C16N+, F-, Cl-, BF4-, SO4(2-), and C12SO3- ions. By consecutive measurements of the strength of ice adhesion toward ion-incorporated polymer brushes on glass it was found that Li+ ions reduce ice adhesion by 40% at -18 °C and 70% at -10 °C. Ag+ ions reduce ice adhesion by 80% at -10 °C relative to unmodified glass. In general, superhydrophilic polyelectrolyte brushes exhibit better anti-icing property at -10 °C compared to partially hydrophobic brushes such as poly(methyl methacrylate) and surfactant exchanged polyelectrolyte brushes. The data are interpreted using the concept of a quasi liquid layer (QLL) that is enhanced in the presence of highly hydrated ions at the interface. It is suggested that the ability of ions to coordinate water is directly related to the efficiency of a given anti-icing coating based on the polyelectrolyte brush concept.

  17. Preparation and Friction Force Microscopy Measurements of Immiscible, Opposing Polymer Brushes

    NARCIS (Netherlands)

    de Beer, Sissi; Kutnyanszky, E.; Müser, M.H.; Vancso, Gyula J.

    2014-01-01

    Solvated polymer brushes are well known to lubricate high-pressure contacts, because they can sustain a positive normal load while maintaining low friction at the interface. Nevertheless, these systems can be sensitive to wear due to interdigitation of the opposing brushes. In a recent publication,

  18. A PET activation study of brush-evoked allodynia in patients with nerve injury pain

    DEFF Research Database (Denmark)

    Witting, Nanna; Kupers, Ron; Svensson, Peter

    2006-01-01

    allodynia. Nine patients with peripheral nerve injury were scanned during rest, brush-evoked allodynia, and brushing of normal contralateral skin. PET data were analyzed for the whole group and for single subjects. Allodynic stimulation activated the contralateral orbitofrontal cortex (BA 11) in every...

  19. Small molecule pinocytosis and clathrin-dependent endocytosis at the intestinal brush border

    DEFF Research Database (Denmark)

    Danielsen, Erik Michael; Hansen, Gert H

    2016-01-01

    compartments, indicating the existence of two different uptake mechanisms operating simultaneously at the brush border. CTB is internalized by clathrin-dependent receptor mediated endocytosis, but surprisingly the toxin also caused a rapid disappearance from the apical cell surface of two major brush border...

  20. Friendship Network and Dental Brushing Behavior among Middle School Students: An Agent Based Modeling Approach.

    Science.gov (United States)

    Sadeghipour, Maryam; Khoshnevisan, Mohammad Hossein; Jafari, Afshin; Shariatpanahi, Seyed Peyman

    2017-01-01

    By using a standard questionnaire, the level of dental brushing frequency was assessed among 201 adolescent female middle school students in Tehran. The initial assessment was repeated after 5 months, in order to observe the dynamics in dental health behavior level. Logistic Regression model was used to evaluate the correlation among individuals' dental health behavior in their social network. A significant correlation on dental brushing habits was detected among groups of friends. This correlation was further spread over the network within the 5 months period. Moreover, it was identified that the average brushing level was improved within the 5 months period. Given that there was a significant correlation between social network's nodes' in-degree value, and brushing level, it was suggested that the observed improvement was partially due to more popularity of individuals with better tooth brushing habit. Agent Based Modeling (ABM) was used to demonstrate the dynamics of dental brushing frequency within a sample of friendship network. Two models with static and dynamic assumptions for the network structure were proposed. The model with dynamic network structure successfully described the dynamics of dental health behavior. Based on this model, on average, every 43 weeks a student changes her brushing habit due to learning from her friends. Finally, three training scenarios were tested by these models in order to evaluate their effectiveness. When training more popular students, considerable improvement in total students' brushing frequency was demonstrated by simulation results.